Cholesterol, statins, and Parkinson’s disease

Eraser deleting the word Cholesterol

A new research report looking at the use of cholesterol-reducing drugs and the risk of developing Parkinson’s disease has just been published in the scientific journal Movement disorders.

The results of that study have led to some pretty startling headlines in the media, which have subsequently led to some pretty startled people who are currently taking the medication called statins.

In todays post, we will look at what statins are, what the study found, and discuss what it means for our understanding of Parkinson’s disease.


Cholesterol forming plaques (yellow) in the lining of arteries. Source: Healthguru

Cholesterol gets a lot of bad press.

Whether it’s high and low, the perfect balance of cholesterol in our blood seems to be critical to our overall health and sense of wellbeing. At least that is what we are constantly being told this by media and medical professionals alike.

But ask yourself this: Why? What exactly is cholesterol?

Good question. What is cholesterol?

Cholesterol (from the Greek ‘chole‘- bile and ‘stereos‘ – solid) is a waxy substance that is circulating our bodies. It is generated by the liver, but it is also found in many foods that we eat (for example, meats and egg yolks).


The chemical structure of Cholesterol. Source: Wikipedia

Cholesterol falls into one of three major classes of lipids – those three classes of lipids being TriglyceridesPhospholipids and Steroids (cholesterol is a steroid). Lipids are major components of the cell membranes and thus very important. Given that the name ‘lipids’ comes from the Greek lipos meaning fat, people often think of lipids simply as fats, but fats more accurately fall into just one class of lipids (Triglycerides).

Like many fats though, cholesterol dose not dissolve in water. As a result, it is transported within the blood system encased in a protein structure called a lipoprotein.


The structure of a lipoprotein; the purple C inside represents cholesterol. Source: Wikipedia

Lipoproteins have a very simple classification system based on their density:

  • very low density lipoprotein (VLDL)
  • low density lipoprotein (LDL)
  • intermediate density lipoprotein (IDL)
  • high density lipoprotein (HDL).

Now understand that all of these different types of lipoproteins contain cholesterol, but they are carrying it to different locations and this is why some of these are referred to as good and bad.

The first three types of lipoproteins carry newly synthesised cholesterol from the liver to various parts of the body, and thus too much of this activity would be bad as it results in an over supply of cholesterol clogging up different areas, such as the arteries.

LDLs, in particular, carry a lot of cholesterol (with approximately 50% of their contents being cholesterol, compared to only 20-30% in the other lipoproteins), and this is why LDLs are often referred to as ‘bad cholesterol’. High levels of LDLs can result in atherosclerosis (or the build-up of fatty material inside your arteries).

Progressive and painless, atherosclerosis develops as cholesterol silently and slowly accumulates in the wall of the artery, in clumps that are called plaques. White blood cells stream in to digest the LDL cholesterol, but over many years the toxic mess of cholesterol and cells becomes an ever enlarging plaque. If the plaque ever ruptures, it could cause clotting which would lead to a heart attack or stroke.


Source: MichelsonMedical

So yeah, some lipoproteins can be considered bad.

HDLs, on the other hand, collects cholesterol and other lipids from cells around the body and take them back to the liver. And this is why HDLs are sometimes referred to as “good cholesterol” because higher concentrations of HDLs are associated with lower rates of atherosclerosis progression (and hopefully regression).

But why is cholesterol important?

While cholesterol is usually associated with what is floating around in your bloodstream, it is also present (and very necessary) in every cell in your body. It helps to produce cell membranes, hormones, vitamin D, and the bile acids that help you digest fat.

It is particularly important for your brain, which contains approximately 25 percent of the cholesterol in your body. Numerous neurodegenerative conditions are associated with cholesterol disfunction (such as Alzheimer’s disease and Huntington’s disease – Click here for more on this). In addition, low levels of cholesterol is associated with violent behaviour (Click here to read more about this).

Are there any associations between cholesterol and Parkinson’s disease?

The associations between cholesterol and Parkinson’s disease is a topic of much debate. While there have been numerous studies investigating cholesterol levels in blood in people with Parkinson’s disease, the results have not been consistent (Click here for a good review on this topic).

Rather than looking at cholesterol directly, a lot of researchers have chosen to focus on the medication that is used to treat high levels of cholesterol – a class of drugs called statins.


Title: Prospective study of statin use and risk of Parkinson disease.
Authors: Gao X, Simon KC, Schwarzschild MA, Ascherio A.
Journal: Arch Neurol. 2012 Mar;69(3):380-4.
PMID: 22410446              (This article is OPEN ACCESS if you would like to read it)

In this study the researchers conduced a prospective study involving the medical details of 38 192 men and 90 874 women from two huge US databases: the Nurses’ Health Study (NHS) and the Health Professionals Follow-Up Study (HPFS).

NHS study was started in 1976 when 121,700 female registered nurses (aged 30 to 55 years) completed a mailed questionnaire. They provided an overview of their medical histories and health-related behaviours. The HPFS study was established in 1986, when 51,529 male health professionals (40 to 75 years) responded to a similar questionnaire. Both the NHS and the HPFS send out follow-up questionnaires every 2 years.

By analysing all of that data, the investigators found 644 cases of Parkinson’s disease (338 women and 306 men). They noticed that the risk of Parkinson’s disease was approximately 25% lower among people currently taking statins when compared to people not using statins. And this association was significant in statin users younger than 60 years of age (P = 0.02).

What are statins?

Also known as HMG-CoA reductase inhibitors, statins are a class of drug that inhibits/blocks an enzyme called 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase.

HMG-CoA reductase is the key enzyme regulating the production of cholesterol from mevalonic acid in the liver. By blocking this process statins help lower the total amount of cholesterol available in your bloodstream.


Source: Myelomacrowd

Statins are used to treat hypercholesterolemia (also called dyslipidemia) which is high levels of cholesterol in the blood. And they are one of the most widely prescribed classes of drugs currently available, with approximately 23 percent of adults in the US report using statin medications (Source).

Now, while the study above found an interesting association between statin use and a lower risk of Parkinson’s disease, the other research published on this topic has not been very consistent. In fact, a review in 2009 found a significant associations between statin use and lower risk of Parkinson’s disease was observed in only two out of five prospective studies (Click here to see that review).

New research published this week has attempted to clear up some of that inconsistency, by starting with a huge dataset and digging deep into the numbers.

So what new research has been published?


Title: Statins may facilitate Parkinson’s disease: Insight gained from a large, national claims database
Authors: Liu GD, Sterling NW, Kong L, Lewis MM, Mailman RB, Chen H, Leslie D, Huang X
Journal: Movement Disorder, 2017 Jun;32(6):913-917.
PMID: 28370314

Using the MarketScan Commercial Claims and Encounters database which catalogues the healthcare use and medical expenditures of more than 50 million employees and their family members each year, the researcher behind that study identified 30,343,035 individuals that fit their initial criteria (that being “all individuals in the database who had 1 year or more of continuous enrolment during January 1, 2008, to December 31, 2012, and were 40 years of age or older at any time during their enrolment”). From this group, the researcher found a total of 21,599 individuals who had been diagnosed with Parkinson’s disease.

In their initial analysis, the researchers found that Parkinson’s disease was positively associated with age, male gender, hypertension, coronary artery disease, and usage of cholesterol-lowering drugs (both statins and non-statins). The condition was negatively associated with hyperlipidemia (or high levels of cholesterol). This result suggests not only that people with higher levels of cholesterol have a reduced chance of developing Parkinson’s disease, but taking medication to lower cholesterol levels may actually increase ones risk of developing the condition.

One interesting finding in the data was the effect that different types of statins had on the association.

Statins can be classified into two basic groups: water soluble (or hydrophilic) and lipid soluble (or lipophilic) statins. Hydrophilic molecule have more favourable interactions with water than with oil, and vice versa for lipophilic molecules.


Hydrophilic vs lipophilic molecules. Source: Riken

Water soluble (Hydrophilic) statins include statins such as pravastatin and rosuvastatin; while all other available statins (eg. atorvastatin, cerivastatin, fluvastatin, lovastatin and simvastatin) are lipophilic.

In this new study, the researchers found that the association between statin use and increased risk of developing Parkinson’s disease was more pronounced for lipophilic statins (a statistically significant 58% increase – P < 0.0001), compared to hydrophilic statins (a non-significant 19% increase – P = 0.25). One possible explanation for this difference is that lipophilic statins (like simvastatin and atorvastatin) cross the blood-brain barrier more easily and may have more effect on the brain than hydrophilic ones.

The investigators also found that this association was most robust during the initial phase of statin treatment. That is to say, the researchers observed a 82% in risk of PD within 1 year of having started statin treatment, and only a 37% increase five years after starting statin treatment.; P < 0.0001). Given this finding, the investigators questioned whether statins may be playing a facilitatory role in the development of Parkinson’s disease – for example, statins may be “unmasking” the condition during its earliest stages.

So statins are bad then?

Can I answer this question with a diplomatic “I don’t know”?

It is difficult to really answer that question based on the results of just this one study. This is mostly because this new finding is in complete contrast to a lot of experimental research over the last few years which has shown statins to be neuroprotective in many models of Parkinson’s disease. Studies such as this one:

Title: Simvastatin inhibits the activation of p21ras and prevents the loss of dopaminergic neurons in a mouse model of Parkinson’s disease.
Authors: Ghosh A, Roy A, Matras J, Brahmachari S, Gendelman HE, Pahan K.
Journal: J Neurosci. 2009 Oct 28;29(43):13543-56.
PMID: 19864567              (This study is OPEN ACCESS if you would like to read it)

In this study, the researchers found that two statins (pravastatin and simvastatin – one hydrophilic and one lipophilic, respectively) both exhibited the ability to suppress the response of helper cells in the brain (called microglial) in a neurotoxin model of Parkinson’s disease. This microglial suppression resulted in a significant neuroprotective effect on the dopamine neurons in these animals.

Another study found more Parkinson’s disease relevant effects from statin treatment:


TItle: Lovastatin ameliorates alpha-synuclein accumulation and oxidation in transgenic mouse models of alpha-synucleinopathies.
Authors: Koob AO, Ubhi K, Paulsson JF, Kelly J, Rockenstein E, Mante M, Adame A, Masliah E.
Journal: Exp Neurol. 2010 Feb;221(2):267-74.
PMID: 19944097            (This study is OPEN ACCESS if you would like to read it)

In this study, the researchers treated two different types of genetically engineered mice (both sets of mice produce very high levels of alpha synuclein – the protein closely associated with Parkinson’s disease) with a statin called lovastatin. In both groups of alpha synuclein producing mice, lovastatin treatment resulted in significant reductions in the levels of cholesterol in their blood when compared to the saline-treated control mice. The treated mice also demonstrated a significant reduction in levels of alpha synuclein clustering (or aggregation) in the brain than untreated mice, and this reduction in alpha synuclein accumulation was associated with a lessening of pathological damage in the brain.

So statins may not be all bad?

One thing many of these studies fail to do is differentiate between whether statins are causing the trouble (or benefit) directly or whether simply lowering cholesterol levels is having a negative impact. That is to say, do statins actually do something else? Other than lowering cholesterol levels, are statins having additional activities that could cause good or bad things to happen?



Source: Liverissues

The recently published study we are reviewing in this post suggested that non-statin cholesterol medication is also positively associated with developing Parkinson’s disease. Thus it may be that statins are not bad, but rather the lowering of cholesterol levels that is. This raises the question of whether high levels of cholesterol are delaying the onset of Parkinson’s disease, and one can only wonder what a cholesterol-based process might be able to tell us about the development of Parkinson’s disease.

If the findings of this latest study are convincingly replicated by other groups, however, we may need to reconsider the use of statins not in our day-to-day clinical practice. At the very least, we will need to predetermine which individuals may be more susceptible to developing Parkinson’s disease following the initiation of statin treatment. It would actually be very interesting to go back to the original data set of this new study and investigate what addition medical features were shared between the people that developed Parkinson’s disease after starting statin treatment. For example, were they all glucose intolerant? One would hope that the investigators are currently doing this.

Are Statins currently being tested in the clinic for Parkinson’s disease?

(Oh boy! Tough question) Yes, they are.

There is currently a nation wide study being conducted in the UK called PD STAT.


The study is being co-ordinated by the Plymouth Hospitals NHS Trust (Devon). For more information, please see their website or click here for the NHS Clinical trials gateway website.

Is this dangerous given the results of the new research study?

(Oh boy! Even tougher question!)

Again, we are asking this question based on the results of one recent study. Replication with independent databases is required before definitive conclusions can be made.

There have, however, been previous clinical studies of statins in neurodegenerative conditions and these drugs have not exhibited any negative effects (that I am aware of). In fact, a clinical trial for multiple sclerosis published in 2014 indicated some positive results for sufferers taking simvastatin:

Title: Effect of high-dose simvastatin on brain atrophy and disability in secondary progressive multiple sclerosis (MS-STAT): a randomised, placebo-controlled, phase 2 trial.
Authors: Chataway J, Schuerer N, Alsanousi A, Chan D, MacManus D, Hunter K, Anderson V, Bangham CR, Clegg S, Nielsen C, Fox NC, Wilkie D, Nicholas JM, Calder VL, Greenwood J, Frost C, Nicholas R.
Journal: Lancet. 2014 Jun 28;383(9936):2213-21.
PMID: 24655729             (This article is OPEN ACCESS if you would like to read it)

In this double-blind clinical study (meaning that both the investigators and the subjects in the study were unaware of which treatment was being administered), 140 people with multiple sclerosis were randomly assigned to receive either the statin drug simvastatin (70 people; 40 mg per day for the first month and then 80 mg per day for the remainder of 18 months) or a placebo treatment (70 people).

Patients were seen at 1, 6, 12, and 24 months into the study, with telephone follow-up at months 3 and 18. MRI brain scans were also made at the start of the trial, and then again at 12 months and 25 months for comparative sake.

The results of the study indicate that high-dose simvastatin was well tolerated and reduced the rate of whole-brain shrinkage compared with the placebo treatment. The mean annualised shrinkage rate was significantly lower in patients in the simvastatin group. The researchers were very pleased with this result and are looking to conduct a larger phase III clinical trial.

Other studies have not demonstrated beneficial results from statin treatment, but they have also not observed a worsening of the disease conditions:

Title: A randomized, double-blind, placebo-controlled trial of simvastatin to treat Alzheimer disease.
Authors:Sano M, Bell KL, Galasko D, Galvin JE, Thomas RG, van Dyck CH, Aisen PS.
Journal: Neurology. 2011 Aug 9;77(6):556-63.
PMID: 21795660            (This article is OPEN ACCESS if you would like to read it)

In this study, the investigators recruited a total of 406 individuals were mild to moderate Alzheimer’s disease, and they were randomly assigned to two groups: 204 to simvastatin (20 mg/day, for 6 weeks then 40 mg per day for the remainder of 18 months) and 202 to placebo control treatment. While Simvastatin displayed no beneficial effects on the progression of symptoms in treated individuals with mild to moderate Alzheimer’s disease (other than significantly lowering of cholesterol levels), the treatment also exhibited no effect on worsening the disease.


So what does it all mean?

Research investigating cholesterol and its association with Parkinson’s disease has been going on for a long time. This week a research report involving a huge database was published which indicated that using cholesterol reducing medication could significantly increase one’s risk of developing Parkinson’s disease.

These results do not mean that someone being administered statins is automatically going to develop Parkinson’s disease, but – if the results are replicated – it may need to be something that physicians should consider before prescribing this class of drug.

Whether ongoing clinical trials of statins and Parkinson’s disease should be reconsidered is a subject for debate well above my pay grade (and only if the current results are replicated independently). It could be that statin treatment (or lowering of cholesterol) may have an ‘unmasking’ effect in some individuals, but does this mean that any beneficial effects in other individuals should be discounted? If preclinical data is correct, for example, statins may reduce alpha synuclein clustering in some people which could be beneficial in Parkinson’s.

As we have said above, further research is required in this area before definitive conclusions can be made. This is particularly important given the inconsistencies of the previous research results in the statin and Parkinson’s disease field of investigation.

EDITORIAL NOTE: The information provided by the SoPD website is for information and educational purposes only. Under no circumstances should it ever be considered medical or actionable advice. It is provided by research scientists, not medical practitioners. Any actions taken – based on what has been read on the website – are the sole responsibility of the reader. Any actions being contemplated by readers should firstly be discussed with a qualified healthcare professional who is aware of your medical history. While some of the information discussed in this post may cause concern, please speak with your medical physician before attempting any change in an existing treatment regime.

The banner for today’s post was sourced from HarvardHealth

Who am I but my BMI


New research was published last week that suggests people with a high body mass index (or BMI) have a reduced risk of developing Parkinson’s disease.

Really? How does that work?

In todays post we will discuss what body mass index is, review the results of the study and consider what this means for our understanding of Parkinson’s disease.

Human Skin Color Variation

Lots of variety. Source: Pinsdaddy

Humans being come in all sorts of different shapes and sizes.

Tall, short, skinny, obese….

The interesting aspect about some of these differences is the way they can make us vulnerable to certain diseases. For example, we have previously discussed how people with red hair have are 4 times more likely to develop Parkinson’s disease than dark haired people (Click here to read that post, and here for a follow up post).

And now we have new research suggesting that your body mass may also influence your risk of developing Parkinson’s disease.

What do you mean by body mass?

Your body mass is simply your weight.

It can be used to determine your approximate level of health by applying it to the body mass index.

And what is the body mass index?


The Body Mass Index. Source: Bioninja

The body mass index (or BMI) – also known as the Quetelet index – is a measure that is derived from the weight and height of an individual. Body mass index can be calculated according to the following formula:


That is simply your weight in kilograms divided by your height in metres squared.

For example, if you were a ridiculously tall (2.08 metres – 6 foot 8) Parkinson’s research scientist with bad hair and an approximate weight of 105kg (230 pounds), your BMI score would be 24.2 (time to put the laptop down and go for some walks). This was calculated by dividing 105 by 4.3 (2.08 x 2.08meters).


The authors BMI score. Source: NHS BMI Calculator

So what is the new research about BMI and Parkinson’s disease?

This is Dr Alastair Noyce:


He leads the PredictPD study (a really interesting longitudinal study to identify people at risk of Parkinson’s disease), which is based out of University College London. He is the lead author of the study.

And this is Prof Nick Wood:


He is the Galton Professor of Genetics, and the neuroscience programme director for Biomedical Research Centre at University College London. He has been at the forefront of many of the discoveries associated with the genetics of Parkinson’s disease, and he is the senior author of the study.

And this is the study:


Title: Estimating the causal influence of body mass index on risk of Parkinson disease: A Mendelian randomisation study.
Authors: Noyce AJ, Kia DA, Hemani G, Nicolas A, Price TR, De Pablo-Fernandez E, Haycock PC, Lewis PA, Foltynie T, Davey Smith G; International Parkinson Disease Genomics Consortium, Schrag A, Lees AJ, Hardy J, Singleton A, Nalls MA, Pearce N, Lawlor DA, Wood NW.
Journal: PLoS Med. 2017 Jun 13;14(6):e1002314.
PMID: 28609445                 (This article is OPEN ACCESS if you would like to read it)

The researchers who published this study were interested in determining whether BMI and the future risk of Parkinson’s disease had any association (as you will see below there has previously been some disagreement about this). They began by collected data from the GIANT (Genetic Investigation of Anthropometric Traits) study. The GIANT study was a huge consortium that was set up identify regions or variations within DNA that could impact body size and shape (such as height and measures of obesity). They didn’t find very many, but the dataset represents an enormous resource for researchers to use (information about 2,554,637 genetic variants from 339,224 individuals of European descent).

They next collected all of the most recent data about genetic variations associated with Parkinson’s disease (7,782,514 genetic variants from 13,708 cases of Parkinson’s disease and 95,282 individuals acting as controls, pooled from 15 independent datasets of individuals of European descent).

Using these two sets of data, the researchers were able to determine any relationship between genetic variants and BMI, and any relationship between those same genetic variants and Parkinson’s disease. Using this approach, they could then determine an estimated change in the risk of Parkinson’s disease per unit change in BMI score.

And when they conducted that analysis, the researchers found genetic variants expected to increase ones BMI score higher by 5 were actually associated with an 18 percent lower risk of Parkinson’s disease. That is to say, higher BMI scores were associated with a lower risk of developing Parkinson’s disease – the odds ratio was 0.82 (1 being no difference) and the range of the odds was 0.69–0.98.

So does this mean I’m allowed to get fat? You know, to prevent Parkinson’s?

No. This would not be advisable.

One of the major limitations of this study (and many studies like it) is that individuals who have a higher BMI score have an increased risk of other diseases (heart disease, etc) which could result in an earlier death. They may die before they were eventually going to develop Parkinson’s disease. This ‘early death’ effect could result in individuals with a lower BMI being over-represented in the group of people diagnosed with Parkinson disease. This is called a “frailty effect”. In an attempt to reduce the possibility of a frailty effect in this study, the researchers conducted a further analysis (called ‘Frailty simulations’) to assess whether any associations they found were affected by mortality selection. This analysis suggested that the frailty effect could at least partially account for the association. That is to say, high BMI people dying earlier could partly explain the reduced frequency of Parkinson’s disease in that group.

In addition, there could also be subgroups within the low or high BMI population that could be affecting the data. The datasets used in the study lack of information about additional possible confounding variables. Confounding variables are factors that could influence the outcome of a study that haven’t been controlled for. In this study, for example, there was no information about smoking or coffee drinking, which have both been found to reduce risk of developing Parkinson’s disease. Perhaps a subset of cases in the high BMI group were serious smokers and coffee drinkers?

So, don’t go changing to a high cholesterol diet just yet.

How does this result compare to previous research on BMI and Parkinson’s disease?

It is fair to say that there has been a lack of consensus in this field of research.

There is certainly evidence to support the results of this new research report. Earlier this year, for example, researchers in Korea reported that brain imaging of 400 people recently diagnosed with Parkinson’s disease suggested a lower BMI might be closely associated with low density of dopaminergic neurons in the midbrain, a region badly affected in Parkinson’s disease (Click here to read more about that study).

But there is also some research that suggests that there no association between BMI and Parkinson’s disease, including this study which analysed data from multiple studies:

Title: Body Mass Index and Risk of Parkinson’s Disease: A Dose-Response Meta-Analysis of Prospective Studies.
Authors: Wang YL, Wang YT, Li JF, Zhang YZ, Yin HL, Han B.
Journal: PLoS One. 2015 Jun 29;10(6):e0131778.
PMID: 26121579              (This article is OPEN ACCESS if you would like to read it)

This study analysed data from 10 different studies and found no association between BMI and risk of developing Parkinson’s disease.

And then there have been studies which have found the opposite effect of the new study – that is lower BMI scores are associated with a lower risk of developing Parkinson’s disease (Click here and here to read more about those studies).

These previous studies, however, have all been observational studies. The beauty of this new research report is that they applied genetic analysis to the question, which has helped them to better define and characterise their population of interest. It will be interesting to see if future studies taking a similar approach can provide some kind of consensus here.

What about BMI after someone is diagnosed with Parkinson’s disease?

Here the picture becomes a little bit clearer.

Weight loss can be a common feature of Parkinson’s disease:

Title: Association Between Change in Body Mass Index, Unified Parkinson’s Disease Rating Scale Scores, and Survival Among Persons With Parkinson Disease: Secondary Analysis of Longitudinal Data From NINDS Exploratory Trials in Parkinson Disease Long-term Study 1.
Authors: Wills AM, Pérez A, Wang J, Su X, Morgan J, Rajan SS, Leehey MA, Pontone GM, Chou KL, Umeh C, Mari Z, Boyd J; NINDS Exploratory Trials in Parkinson Disease (NET-PD) Investigators.
Journal: JAMA Neurol. 2016 Mar;73(3):321-8.
PMID: 26751506             (This article is OPEN ACCESS if you would like to read it)

In this study, 1673 people with Parkinson’s disease were recruited and followed over 3-6 years. Of these participants, 158 (9.4%) experienced weight loss (or a decrease in BMI), while 233 (13.9%) experienced weight gain (an increase in BMI). The weight loss group demonstrated an increase in the Unified Parkinson’s Disease Rating Scale (UPDRS) motor score (which indicates a worsening of Parkinsonian features), while the weight gain group actually exhibited a subtle decrease in their motor scores (an improvement in Parkinson’s features).

And this association between wait loss and worsening disease state is supported in a second study:

Title: Weight loss and impact on quality of life in Parkinson’s disease.
Authors: Akbar U, He Y, Dai Y, Hack N, Malaty I, McFarland NR, Hess C, Schmidt P, Wu S, Okun MS.
Journal: PLoS One. 2015 May 4;10(5):e0124541.
PMID: 25938478              (This article is OPEN ACCESS if you would like to read it)

In this study of 1718 people with Parkinson’s disease, the researchers found that more rapid weight loss was associated with higher number of co-morbidities (other medical complications), older age, higher L-dopa usage, and decreased health-related quality of life.

Thus weight loss is something for everyone to keep an eye on.

IMPORTANT NOTE: Weight loss can become apparent with an increase in dykinesias, but this is generally due to increased activity levels increasing levels of metabolism.

What does it all mean?

Using very large datasets, researchers in London have recently found that higher BMI scores are associated with a lower risk of developing Parkinson’s disease. This result is very interesting, even if much of the effect could be accounted for by the early mortality problem in the high BMI group.

Exactly how high BMI could infer neuroprotection or reduced chance of incurring the condition is still to be determined, and understanding the mechanisms of this effect could provide new understanding about the disease. It is ill advised, however, to consider that increasing ones BMI as a practical strategy for reducing the risk of developing Parkinson’s disease.

The banner for todays post was sourced from themoderngladiator

BioRxiv – open access preprints


For the vast majority of the general population, science is consumed via mass media head lines and carefully edited summaries of the research.

The result of this simplified end product is an ignorance of the process that researchers need to deal with in order to get their research in the public domain.

As part of our efforts to educate the general public about the scientific research of Parkinson’s disease, it is necessary to also make them aware of that process, the issues associated with it, and how it is changing over time.

In todays post, we will look at how new research reports are being made available to the public domain before they are published.


Getting research into the public domain. Source: STAT

Every morning here at the SoPD, we look at what new research has entered the public domain over night and try to highlight some of the Parkinson’s disease relevant bits on our Twitter account (@ScienceofPD).

To the frustration of many of our followers, however, much of that research sits behind the pay-to-view walls of big publishing houses. One is allowed to read the abstract of the research report in most cases, but not the full report.

Given that charity money and tax payer dollars are paying for much of the research being conducted, and for the publication fee (approx. $1500 per report on average) to get the report into the journal, there is little debate as to the lack of public good in such a system. To make matter worse, many of the scientists doing the research can not access the published research reports, because their universities and research institutes can not afford the hefty access fees for all of the journals.


Source: Libguides

To be fair, the large publishing houses have recognised that this is not a sustainable business model, and they have put forward the development of open-access web-based science journals, such as Nature communications, Scientific reports, and Cell reports. But the fees for publishing in these journals can in some cases be higher than the closed access publications.

This is crazy. What can we do about it?

Well, there have been efforts for some time to improve the situation.

Projects like the Public Library of Science (or PLOS) have been very popular and are now becoming a real force on the scientific publishing landscape (they recently celebrated their 10 year anniversary and during that time they have published more than 165,000 research articles). But they too have costs associated with maintaining their service and publications fees can still be significant.


Is there an easier way of making this research available?

So this is Prof Paul Ginsparg.


Source: Wikipedia

Looks like the mad scientist type right? Don’t be fooled. He’s awesome! Prof Ginsparg is a professor of Physics and Computing & Information Science at Cornell University.

Back in 1991, he started a repository of pre-print publications in the field of physics. The repository was named, and it allowed physics researchers to share and comment on each others research reports before they were actually published.

The site slowly became an overnight sensation.

The number of manuscripts deposited at arXiv passed the half-million mark on October 3, 2008, the million manuscript mark by the end of 2014 (with a submission rate of more than 8,000 manuscripts per month). The site currently has 1,257,315 manuscripts that are freely available to access. A future nobel prize winning bit of research is probably in there!

Now, by their very nature, and in a very general sense, biomedical researchers are a jealous bunch.

For many years they looked on with envy at the hive of activity going on at arXiv and wished that they had something like it themselves. And now they do! In November 2013, Cold Spring Harbor Laboratory in New York launched BioRxiv.


Source: BioRxiv

And the website is very quickly becoming a popular destination: by April 21, 2017, >10,000 manuscript had been posted, at a current rate of over 800 manuscripts per month (Source).

Recently they got a huge nod of financial support from the Chan Zuckerberg Initiative – a foundation set up by Facebook founder Mark Zuckerberg and his wife Priscilla Chan to “advance human potential and promote equality in areas such as health, education, scientific research and energy” (Wikipedia).


Source: ChangZuckerberg

In April of this year, the Chan Zuckerberg Initiative announced a partnership with Cold Spring Harbor Laboratory to help support the site (Click here to see the press release).

So what is bioRxiv?

bioRxiv is a free OPEN ACCESS service that allows researchers to submit draft copies of scientific papers — called preprints — for their colleagues to read and comment on before they are actually published in peer-reviewed scientific journals.

Here are two videos explaining the idea:

Sounds great right?

To demonstrate how the bioRxiv process works, we have selected an interesting manuscript from the database that we would like to review here on the SoPD.

This is the article:


Title: In Vivo Phenotyping Of Parkinson-Specific Stem Cells Reveals Increased a-Synuclein Levels But No Spreading
Authors: Hemmer K, Smits LM, Bolognin S, Schwamborn JC
Database: BioRxiv
PMID: N/A                   (You can access the manuscript by clicking here)

In this study (which was posted on bioRxiv on the 19th May, 2017), the researchers have acquired skin cells from an 81 year old female with Parkinson’s disease who carries a mutation (G2019S) in the LRRK2 gene.

Mutations in the Leucine-rich repeat kinase 2 (or Lrrk2) gene are associated with an increased risk of developing Parkinson’s disease. The most common mutation of LRRK2 gene is G2019S, which is present in 5–6% of all familial cases of Parkinson’s disease, and is also present in 1–2% of all sporadic cases. We have previously discussed Lrrk2 (Click here to read that post).


The structure of Lrrk2 and where various mutations lie. Source: Intech

The skin cells were transformed using a bit of biological magic in induced pluripotent stem (or IPS) cells. We have previously discussed IPS cells and how they are created (Click here to read that post). By changing a subjects skin cell into a stem cell, researchers can grow the cell into any type of cell and then investigate a particular disease on a very individualised basis (the future of personalised medicine don’t you know).


IPS cell options available to Parkinson’s disease. Source: Nature

Using this IPS cell with a mutation in the LRRK2 gene, the researchers behind todays manuscript next grew the cells in culture and encouraged the cells to become dopamine producing cells (these are some of the most vulnerable cells in Parkinson’s disease). The investigators had previously shown that neurons grown in culture from cells with the G2019S mutation in the LRRK2 gene have elevated levels of of the Parkinson’s disease protein alpha Synuclein (Click here to read that OPEN ACCESS paper).

In this present study, the investigators wanted to know if these cells would also have elevated levels of alpha synuclein when transplanted into the brain. Their results indicate that the cells did. Next, the investigators wanted to use this transplantation model to see if the high levels of alpha synuclein in the transplanted cells would lead to the protein being passed to neighbouring cells.

Why did they want to do that?

One of the current theories regarding the mechanisms underlying the progressive spread of Parkinson’s disease is that the protein alpha synuclein is lead culprit. Under normal conditions, alpha synuclein usually floats around as an individual protein (or monomer), but sometime it starts to cluster (or aggregate) with other monomers of alpha synuclein and these form what we call oligomers. These oligomers are believed to be a toxic form of alpha synuclein that is being passed from cell to cell. And it ‘seeds’ the disease in each cell it is passed on to (Click here for a very good OPEN ACCESS review of this topic).

Mechanism of syunuclein propagation and fibrillization

The passing of alpha synuclein between brain cells. Source: Nature

There have been postmortem analysis studies of the brains from people with Parkinson’s who have had cell transplantation therapy back in the 1990s. The analysis shows that some of the transplanted cells have evidence of toxic alpha synuclein in them – some of those cells have Lewy bodies in them, suggesting that the disease has been passed on to the healthy introduced cells from the diseased brain (Click here for the OPEN ACCESS research report about this).

In the current bioRxiv study, the investigators wanted to ask the reverse question:

Can unhealthy, toxic alpha synuclein producing cells cause the disease to spread into a healthy brain?

So after transplanted the Lrrk2 mutant cells into the brains of mice, they waited 11 weeks to see if the alpha synuclein would be passed on to the surrounding brain. According to their results, the unhealthy alpha synuclein did not transfer. They found no increase in levels of alpha synuclein in the cells surrounding the transplanted cells. The researchers concluded that within the parameters of their experiment, Parkinson’s disease-associated alpha synuclein spreading was not detected.

Interesting. When will this manuscript be published in a scientific journal?

We have no idea.

One sad truth of the old system of publication is: it may never be.

And this illustrates one of the beautiful features of bioRxiv.

This manuscript is probably going through the peer-review process at a particular scientific journal at the moment in order for it to be properly published. It is a process that will take several months. Independent reviewers will provide a critique of the work and either agree that it is ready for publication, suggest improvements that should be made before it can be published, or reject it outright due to possible flaws or general lack of impact (depending on the calibre of the journal – the big journals seem to only want sexy science). It is a brutal procedure and some manuscripts never actually survive it to get published, thus depriving the world of what should be freely available research results.

And this is where bioRxiv provides us with a useful forum to present scientific biological research that may never reach publication. Perhaps the researchers never actually intended to publish their findings, and just wanted to let the world know that someone had attempted the experiment and these are the results they got (there is a terrible bias in the world of research publishing to only publish positive results).

The point is: with bioRxiv we can have free access to the research before it is published and we do not have to wait for the slow peer-review process.

And there is definitely some public good in that.

EDITORS NOTE HERE: We are not suggesting for a second that the peer-review process should be done away with. The peer-review process is an essential and necessary aspect of scientific research, which helps to limit fraud and inaccuracies in the science being conducted.

What does it all mean?

This post may be boring for some of our regular readers, but it is important for everyone to understand that there are powerful forces at work in the background of scientific research that will determine the future of how information is disseminated to both the research community and general population. It is useful to be aware of these changes.

We hope that some of our readers will be bold/adventurous and have a look at some of what is on offer in the BioRxiv database. Maybe not now, but in the future. It will hopefully become a tremendous resource.

And we certainly encourage fellow researchers to use it (most of the big journals now accept preprint manuscripts being made available on sites like bioRxiv – click here to see a list of the journals that accept this practise) and some journals also allow authors to submit their manuscript directly to a journal’s submission system through bioRxiv via the bioRxiv to Journals (B2J) initiative (Click here for a list of the journals accepting this practise).

The times they are a changing…

The banner for today’s post was sourced from ScienceMag

Are Dyskinesias days NAM-bered?


Addex Therapeutics and the Michael J Fox Foundation are preparing to initiate a new clinical trial testing a new drug called Dipraglurant on levodopa-induced dyskinesia (Source).

Dipraglurant is a mGluR5 negative allosteric modulator (don’t panic, it’s not as complicated as it sounds).

In today’s post, we’ll explain what all of that means and look at the science behind this new treatment.


An example of a person with dyskinesia. Source: JAMA Neurology

For anyone familiar with Parkinson’s disease, they will know that long term use of the treatment L-dopa can lead to two possible outcomes:

  1. The treatment loses it’s impact, requiring ever higher doses to be administered
  2. The appearance of dykinesias

Now, not everyone taking L-dopa will be affected by both of these outcomes, but people with young, onset Parkinson’s disease do seem to be at risk of developing L-dopa induced dykinesias.

What are Dyskinesias?

Dyskinesias (from Greek: dys – abnormal; and kinēsis – motion, movement) are simply a category of movement disorders that are characterised by involuntary muscle movements. And they are certainly not specific to Parkinson’s disease.

As we have suggested above, they are associated in Parkinson’s disease with long-term use of L-dopa.

Below is a video of two legends: the late Tom Isaacs (who co-founded the Cure Parkinson’s Trust) and David Sangster (he founded They were both diagnosed with Parkinson’s disease in their late 20’s. Tom, having lived with Parkinson’s for 20 years at the time of this video provides a good example of what dyskinesias look like:

As you can see, dyskinesias are a debilitating issue for anyone who suffers them.

How do dyskinesias develop in Parkinson’s disease?

Before being diagnosed and beginning a course of L-dopa, the locomotion parts of the brain in a person with Parkinson’s disease gradually becomes more and more inhibited. This increasing inhibition results in the slowness and difficulty in initiating movement that characterises this condition. A person with Parkinson’s may want to move, but they can’t.

They are akinetic (from Greek: a-, not, without; and kinēsis – motion).


Drawing of an akinetic individual with Parkinson’s disease, by Sir William Richard Gowers
Source: Wikipedia

L-dopa tablets provide the brain with the precursor to the chemical dopamine. Dopamine producing cells are lost in Parkinson’s disease, so replacing the missing dopamine is one way to treat the motor features of the condition. Simply giving people pills of dopamine is a non-starter: dopamine is unstable, breaks down too quickly, and (strangely) has a very hard time getting into the brain. L-dopa, on the other hand, is very robust and has no problem getting into the brain.


Sinemet is L-dopa. Source: Drugs

Once inside the brain, L-dopa is quickly converted into dopamine. It is changed into dopamine by an enzyme called DOPA decarboxylase, and this change rapidly increases the levels of dopamine in the brain, allowing the locomotion parts of the brain to function more normally.


The chemical conversion of L-dopa to dopamine. Source: Nootrobox

In understanding this process, it is important to appreciate that when an L-dopa tablet is consumed and L-dopa enters the brain, there is a rapid increase in the levels of dopamine. A ‘spike’ in the supply of dopamine, if you will, and this will last for the next few hours, before the dopamine is used up.

As the effects of the L-dopa tablet wear off, another tablet will be required. This use of multiple L-dopa pills across the day gives rise to a wave-like shape to the dopamine levels in the brain over the course of the day (see the figure below). The first pill in the morning will quickly lift the levels of dopamine enough that the individual will no longer feel akinetic. This will allow them to be able to function with normal controlled movement for several hours before the L-dopa begins to wear off. As the L-dopa wears off, the dopamine levels in the brain drop back towards levels that will leave the person feeling akinetic and at this point another L-dopa tablet is required.


After several years of L-dopa use, many people with Parkinson’s disease will experience a weaker response to each tablet. They will also find that they have more time during which they will be unable to move (exhibiting akinesia). This is simply the result of the progression of Parkinson’s disease – L-dopa treats the motor features of the disease but only hides/masks the fact that the disease is still progressing.

To combat this shorter response time, the dose of L-dopa is increased. This will result in increasing levels of dopamine in the brain (as illustrated by the higher wave form over time in the image below). It will take more L-dopa medication induced dopamine to lift the individual out of the akinetic state.


This increasing of L-dopa dosage, however, is often associated with the gradual development of abnormal involuntary movements that appear when the levels of L-dopa induced dopamine are the highest.

These are the dyskinesias.

Are there different types of dyskinesias?

Yes there are.

Dyskinesias have been broken down into many different subtypes, but the two main types of dyskinesia are:

Chorea – these are involuntary, irregular, purposeless, and unsustained movements. To an observer, Chorea will look like a very disorganised/uncoordinated attempt at dancing (hence the name, from the Greek word ‘χορεία’ which means ‘dance’). While the overall activity of the body can appear continuous, the individual movements are brief, infrequent and isolated. Chorea can cause problems with maintaining a sustained muscle contraction,  which may result in affected people dropping things or even falling over.

Dystonia – these are sustained muscle contractions. They often occur at rest and can be either focal or generalized. Focal dystonias are involuntary contractions in a single body part, for example the upper facial area. Generalized dystonia, as the name suggests, are contraction affecting multiple body regions at the same time, typically the trunk, one or both legs, and another body part. The intensity of muscular movements in sufferers can fluctuate, and symptoms usually worsen during periods of fatigue or stress.

We have previously discussed the current treatment options for dyskinesias (click here to see that post).

Ok, so what clinical trials are Addex Therapeutics and the Michael J Fox Foundation preparing and why?

They are preparing to take a drug called Dipraglurant through phase III testing for L-dopa inducing dyskinesias in Parkinson’s disease. Dipraglurant is a mGluR5 negative allosteric modulator.

And yes, I know what you are going to ask next: what does any of that mean?

Ok, so mGluR5 (or Metabotropic glutamate receptor 5) is a G protein-coupled receptor. This is a structure that sits in the skin of a cell (the cell membrane), with one part exposed to the outside world – waiting for a chemical to bind to it – while another part is inside the cell, ready to act when the outside part is activated. The outside part of the structure is called the receptor.

Metabotropic receptors are a type of receptor that is indirectly linked with channels in cell membrane. These channels open and close, allowing specific elements to enter the cell. When a chemical (or agonist) binds to the receptor and it becomes activated, the part of the structure inside the cell will send a signal to the channel via a messenger (called a G-protein).

The chemical that binds to mGluR5 is the neurotransmitter glutamate.


Metabotropic glutamate receptor 5 activation. Source: Nature

But what about the “negative allosteric modulator” part of ‘mGluR5 negative allosteric modulator’

Good question.

This is the key part of this new approach. Allosteric modulators are a new class of orally available small molecule therapeutic agents. Traditionally, most marketed drugs bind directly to the same part of receptors that the body’s own natural occurring proteins attach to. But this means that those drugs are competing with those endogenous proteins, and this can limit the potential effect of the drug.

Allosteric modulators get around this problem by binding to a different parts of the receptor. And instead of simply turning on or off the receptor, allosteric modulators can either turn up the volume of the signal being sent by the receptor or decrease the signals. This means that when the body’s naturally occurring protein binds in the receptor, allosteric modulators can either amplify the effect or reduce it depending on which type of allosteric modulators is being administered.


How Allosteric modulators work. Source: Addrex Thereapeutics

There are two different types of allosteric modulators: positive and negative. And as the label suggests, positive allosteric modulators (or PAMs) increase the signal from the receptor while negative allosteric modulators (or NAMs) reduce the signal.

So Dipraglurant turns down the volume of the signal from the mGluR5 receptor?


By turning down the volume of the glutamate receptor mGluR5, researchers believe that we can reduce the severity of dyskinesias.

But hang on a second. Why are we looking at glutamate in dyskinesias? Isn’t dopamine the chemical of interest in Parkinson’s disease?

So almost 10 years ago, some researchers noticed something interesting in the brains of Parkinsonian monkeys that had developed dyskinesias:

Title: mGluR5 metabotropic glutamate receptors and dyskinesias in MPTP monkeys.
Authors: Samadi P, Grégoire L, Morissette M, Calon F, Hadj Tahar A, Dridi M, Belanger N, Meltzer LT, Bédard PJ, Di Paolo T.
Journal: Neurobiol Aging. 2008 Jul;29(7):1040-51.
PMID: 17353071

The researchers conducting this study induced Parkinson’s disease in monkeys using a neurotoxin called MPTP, and they then treated the monkeys with L-dopa until they began to develop dyskinesias. At this point when they looked in the brains of these monkeys, the researchers noticed a significant increase in the levels of mGluR5, which was associated with the dyskinesias. This finding led the researchers to speculate that reducing mGluR5 levels might reduce dyskinesias.

And it did!

Subsequent preclinical research indicated that targeting mGluR5 might be useful in treating dyskinesias, especially with negative allosteric modulators:

Title: The mGluR5 negative allosteric modulator dipraglurant reduces dyskinesia in the MPTP macaque model
Authors: Bezard E, Pioli EY, Li Q, Girard F, Mutel V, Keywood C, Tison F, Rascol O, Poli SM.
Journal: Mov Disord. 2014 Jul;29(8):1074-9.
PMID: 24865335

In this study, the researchers tested the efficacy of dipraglurant in Parkinsonian primates  that had developed L-dopa induced dyskinesias. They tested three different doses of the drug (3, 10, and 30 mg/kg).

Dipraglurant significantly reduced dyskinesias in the monkeys, with best effect being reached using the 30 mg/kg dose. Importantly, the dipraglurant treatment had no impact on the efficacy of L-dopa which was still being used to treat the monkeys Parkinson’s features.

This research lead to a clinical trials in man, and last year Addex Therapeutics published the results of their phase IIa clinical trial of Dipraglurant (also called ADX-48621):


Title: A Phase 2A Trial of the Novel mGluR5-Negative Allosteric Modulator Dipraglurant for Levodopa-Induced Dyskinesia in Parkinson’s Disease.
Authors: Tison F, Keywood C, Wakefield M, Durif F, Corvol JC, Eggert K, Lew M, Isaacson S, Bezard E, Poli SM, Goetz CG, Trenkwalder C, Rascol O.
Journal: Mov Disord. 2016 Sep;31(9):1373-80.
PMID: 27214664

The Phase IIa double-blind, placebo-controlled, randomised trial was a dose escalation study, conducted in 76 patients with Parkinson’s disease L-dopa-induced dyskinesia – 52 subjects were given dipraglurant and 24 received a placebo treatment. The dose escalation assessment of dipraglurant started at 50 mg once daily to 100 mg 3 times daily. The study was conducted over 4 weeks.

The investigators found that dipraglurant significantly reduced the dyskinesias on both day 1 of the study and on day 14, and this treatment did not result in any worsening of the Parkinsonian features. And remember that this was a double blind study, so both the investigators and the participants had no idea which treatment was being given to each subject. Thus little bias can influence the outcome, indicating that dipraglurant really is having a beneficial effect on dyskinesias.

The company suggested that dipraglurant’s efficacy in reducing L-dopa-induced dyskinesia warrants further investigations in a larger number of patients. And this is what the company is now doing with the help of the Michael J. Fox Foundation (MJFF). In addition, dipraglurant’s potential benefits on dystonia are also going to be investigated with support from the Dystonia Medical Research Foundation (DMRF).

And the really encouraging aspect of this research is that Addex Therapeutics are not the only research group achieving significant beneficial results for dykinesias using this treatment approach (click here to read about other NAM-based clinical studies for dyskinesias).

Fingers crossed for more positive results here.

What happens next?

L-dopa induced dyskinesias can be one of the most debilitating aspects of living with Parkinson’s disease, particularly for the early-onset forms of the condition. A great deal of research is being conducted in order to alleviate these complications, and we are now starting to see positive clinical results starting to flow from that research.

These results are using new type of therapeutic drug that are designed to increase or decrease the level of a signal occurring in a cell without interfering with the normal functioning of the chemicals controlling the activation of that signal.

This is really impressive biology.

The banner for today’s post was sourced from Steam

The Melanoma drug from MODAG


A build up of a protein called alpha synuclein inside neurons is one of the characteristic feature of the Parkinsonian brain. This protein is believed to be partly responsible for the loss of dopamine neurons in this condition.

A similar build up of alpha synuclein is also seen in the deadly skin cancer, Melanoma… but those cells don’t die (?!?)… in fact, they just keep on dividing.

Why is there this critical difference?

In today’s post we look at an interesting new study that may have solved this mystery.


A melanoma. Source: Huffington Post

Parkinson’s disease has a very strange relationship with the skin cancer melanoma.

As we have stated in previous posts (Click here, herehere and here to read those posts) people with Parkinson’s disease are 2-8 times more likely to develop melanoma than people without Parkinson’s (And this finding has been replicated a few times: Olsen et al, 2005; Olsen et al, 2006; Driver et al 2007; Gao et al 2009; Lo et al 2010; Bertoni et al 2010;Schwid et al 2010; Ferreira et al, 2010Inzelberg et al, 2011; Liu et al 2011; Kareus et al 2012; Wirdefeldt et al 2014; Catalá-López et al 2014; Constantinescu et al 2014; Ong et al 2014).

The truly baffling detail in this story, however, is that this relationship is reciprocal – if you have melanoma you are almost 3 times more likely to develop Parkinson’s disease than someone without melanoma (Source: Baade et al 2007; Gao et al 2009).

What is melanoma exactly?

Melanoma is a type of skin cancer.

It develops from the pigment-containing cells known as melanocytes. Melanocytes are melanin-producing cells located in the bottom layer (the stratum basale) of the skin’s outer layer (or epidermis).


The location of melanocytes in the skin. Source: Wikipedia

Melanocytes produce melanin, which is a pigment found in the skin, eyes, and hair. It is also found in the brain in certain types of cells, such as dopamine neurons (where it is referred to as neuromelanin).


Neuromelanin (brown) in dopamine neurons. Source: Schatz

Melanomas are usually caused by DNA damage resulting from exposure to ultraviolet radiation. Ultraviolet radiation from tanning beds increases the risk of melanoma (Source), as does excessive air travel (Source), or simply spending to much time sun bathing.

Approximately 2.2% of men and women will be diagnosed with melanoma at some point during their lives (Source). In women, melanomas most commonly occur on the legs, while in men they are most common on the back. Melanoma makes up 5% of all cancers (Source).

Generally, melanomas is one of the safer cancers, as it can usually be detected early by visual inspection. This cancer is made dangerous, however, by its ability to metastasise (or spread to other organs in the body).


The stages of melanoma. Source: Pathophys

Are there any genetic associations between Parkinson’s disease and melanoma?


When the common genetics mutations that increase the risk of both conditions were previously analysed, it was apparent that none of the known Parkinson’s mutations make someone more susceptible to melanoma, and likewise none of the melanoma-associated genetic mutations make a person vulnerable to Parkinson’s disease (Meng et al 2012;Dong et al 2014; Elincx-Benizri et al 2014).

In fact, researchers have only found very weak genetic connections between two conditions (Click here to read our previous post on this). It’s a real mystery.

Are there any other connections between Parkinson’s disease and melanoma?


Another shared feature of both Parkinson’s disease and melanoma is the build up of a protein called alpha synuclein. Alpha synuclein is believed to be one of the villains in Parkinson’s disease – building up inside a cell, becoming toxic, and eventually killing that cell.

But recently researchers noticed that melanoma also has a build up of alpha synuclein, but those cells don’t die:


Title: Parkinson’s disease-related protein, alpha-synuclein, in malignant melanoma
Authors: Matsuo Y, Kamitani T.
Journal: PLoS One. 2010 May 5;5(5):e10481.
PMID: 20463956               (This article is OPEN ACCESS if you would like to read it)

In this study, researchers from Japan found that alpha synuclein was detected in 86% of the primary and 85% of the metastatic melanoma. Understand that the protein is not detectable in the non-melanoma cancer cells.

So what is it doing in melanoma cells?

Recently, researchers from Germany believe that they have found the answer to this question:


Title: Treatment with diphenyl-pyrazole compound anle138b/c reveals that α-synuclein protects melanoma cells from autophagic cell death
Authors: Turriani E, Lázaro DF, Ryazanov S, Leonov A, Giese A, Schön M, Schön MP, Griesinger C, Outeiro TF, Arndt-Jovin DJ, Becker D
Journal: Proc Natl Acad Sci U S A. 2017 Jun 5. pii: 201700200. doi: 10.1073/pnas.1700200114
PMID: 28584093

In their study, the German researchers looked at levels of alpha synuclein in melanoma cells. They took the melanoma cells that produced the most alpha synuclein and treated those cells with a chemical that inhibits the toxic form of alpha synuclein (which results from the accumulation of the protein).

What they observed next was fascinating: the cell morphology (or physically) changed, leading to massive melanoma cell death. The investigators found that this cell death was caused by instability of mitochondria and a major dysfunction in the autophagy process.

Mitochondria, you may recall, are the power house of each cell. They keep the lights on. Without them, the lights go out and the cell dies.


Mitochondria and their location in the cell. Source: NCBI

Autophagy is the garbage disposal/recycling process within each cell, which is an absolutely essential function. Without autophagy, old proteins and mitochondria will pile up making the cell sick and eventually it dies. Through the process of autophagy, the cell can break down the old protein, clearing the way for fresh new proteins to do their job.


The process of autophagy. Source: Wormbook

Waste material inside a cell is collected in membranes that form sacs (called vesicles). These vesicles then bind to another sac (called a lysosome) which contains enzymes that will breakdown and degrade the waste material. The degraded waste material can then be recycled or disposed of by spitting it out of the cell.

What the German research have found is that the high levels of alpha synuclein keep the mitochondria stable and the autophagy process working at a level that helps to keeps the cancer cell alive.

Next, they replicated this cell culture research in mice with melanoma tumors. When the mice were treated with the chemical that inhibits the toxic form of alpha synuclein, the cancer cancer became malformed and the autophagy process was blocked.

The researchers concluded that “alpha synuclein, which in PD exerts severe toxic functions, promotes and thereby is highly beneficial to the survival of melanoma in its advanced stages”.

So what does all of this mean for Parkinson’s disease?

Well, this is where the story gets really interesting.

You may be pleased to know that the chemical (called Anle138b) which was used to inhibit the toxic form of alpha synuclein in the melanoma cells, also works in models of Parkinson’s disease:


Title: Anle138b: a novel oligomer modulator for disease-modifying therapy of neurodegenerative diseases such as prion and Parkinson’s disease.
Authors: Wagner J, Ryazanov S, Leonov A, Levin J, Shi S, Schmidt F, Prix C, Pan-Montojo F, Bertsch U, Mitteregger-Kretzschmar G, Geissen M, Eiden M, Leidel F, Hirschberger T, Deeg AA, Krauth JJ, Zinth W, Tavan P, Pilger J, Zweckstetter M, Frank T, Bähr M, Weishaupt JH, Uhr M, Urlaub H, Teichmann U, Samwer M, Bötzel K, Groschup M, Kretzschmar H, Griesinger C, Giese A.
Journal: Acta Neuropathol. 2013 Jun;125(6):795-813
PMID: 23604588              (This article is OPEN ACCESS if you would like to read it)

In this first study the researchers discovered Anle138b by conducted a large screening study to identify for molecules that could inhibit the toxic form of alpha synuclein.

They next tested Anle138b in both cell culture and rodent models of Parkinson’s disease and found it to be neuroprotective and very good at inhibiting the toxic form of alpha synuclein. And the treatment looks to be very effective. In the image below you can see dark staining of toxic alpha synuclein in the left panel from the brain of an untreated mouse, but very little staining in the right panel from an Anle138b treated mouse.



Toxic form of alpha synuclein (dark staining). Source: Max-Planck

Importantly, Anle138b does not interfere with normal behaviour of alpha synuclein in the mice (such as production of the protein, correct functioning, and eventual degradation/disposal of the protein), but it does act as an inhibitor of alpha synuclein clustering or aggregation (the toxic form of the protein). In addition, the investigators found no toxic effects of Anle138b in any of their experiments even after long-term high-dose treatment (more than one year).

And in a follow up study, the drug was effective even if it was given after the disease model had started:


Title: The oligomer modulator anle138b inhibits disease progression in a Parkinson mouse model even with treatment started after disease onset
Authors: Levin J, Schmidt F, Boehm C, Prix C, Bötzel K, Ryazanov S, Leonov A, Griesinger C, Giese A.
Journal: Acta Neuropathol. 2014 May;127(5):779-80.
PMID: 24615514                (This article is OPEN ACCESS if you would like to read it)

During the first study, the researchers had started Anle138b treatment in the mouse model of Parkinson’s disease at a very young age. In this study, however, the investigators began treatment only as the symptoms were starting to show, and Anle138b was found to significantly improve the overall survival of the mice.

One particularly interesting aspect of Anle138b function in the brain is that it does not appear to change the level of the autophagy suggesting that the biological effects of treatment with Anle138b is cell-type–specific (Click here to read more about this). In cancer cells, it is having a different effect to that in brain cells. These differences in effect may also relate to disease conditions though, as Anle138b was not neuroprotective in a mouse model of Multiple System Atrophy (MSA; Click here to read more about this).

Is Anle138b being tested in the clinic?

Not yet.

Ludwig-Maximilians-Universität München and the Max Planck Institute for Biophysical Chemistry (Göttingen) have spun off a company called MODAG GmbH that is looking to advance Anle138b to the clinic (Click here for the press release). The Michael J Fox Foundation are helping to fund more preclinical development of this treatment (Click here to read more about this).

We will be watching their progress with interest.

What does it all mean?

Summing up: There are many mysteries surrounding Parkinson’s disease, but some researchers from Germany may have just solved one of them and at the same time developed a potentially useful new treatment.

They have discovered that the Parkinson’s associated protein, alpha synuclein, which is produced in large amounts in the skin cancer melanoma, is actually playing an important role in keeping those cancer cells alive. By finding a molecule that can block the build up of alpha synuclein, they have not only found a treatment for melanoma, but also potentially one for Parkinson’s disease.

And given that both diseases are closely associated, this could be seen as a great step forward. Two birds with one stone as the saying goes.

The banner for today’s post was sourced from Wikipedia

Flu jabs and Parkinson’s disease


Our apologies to anyone who is squeamish about needles, but this is generally how most people get their seasonal flu vaccination.

Why are we talking about flu vaccines?

Because new research, published last week, suggests everyone should be going out and getting them in the hope of reducing our risk of Parkinson’s disease.

In today’s post we will review the research, exactly what a flu vaccine is, and how it relates to Parkinson’s disease.


Electron micro photograph of Influenza viruses. Source: Neuro-hemin

Long time readers of the SoPD blog will know that I have a particular fascination with theories regarding a viral or microbial role in the development of Parkinson’s disease (the ‘idiopathic’ – or arising spontaneously – variety at least).


Numerous reasons. For example:

  • The targeted nature of the condition (why are only selective groups of cells are lost in the brain during the early stages of the condition?)
  • The unexplained protein aggregation (eg. Lewy bodies; could they be a cellular defensive mechanism against viruses/microbes – Click here to read more on this idea)
  • The asymmetry of the onset (why do tremors start on only one side of the body in most cases?)

And we have previously discussed research here on the website regarding possible associations between Parkinson’s disease and and various types of viruses (including Hepatitis C, Herpes Simplex, and Influenza).

Today we re-visit influenza as new research has been published on this topic.

What is influenza?

Influenza is a single-stranded, RNA virus of the orthomyxovirus family of viruses.


A schematic of the influenza virus. Source: CDC

It is the virus that causes ‘the flu’ – (runny nose, sore throat, coughing, and fatigue) – with the symptom arising two days after exposure and lasting for about a week. In humans, there are three types of influenza viruses, called Type A, Type B, and Type C. Type A are the most virulent in humans. The influenza virus behind both of the outbreaks in the 1918 pandemic was a Type A.


Schematic of Influenza virus. Source: Bcm

As the image above indicates, the influenza virus has a rounded shape, with “HA” (hemagglutinin) and “NA” (neuraminidases) proteins on the outer surface of the virus. The HA protein allows the virus to stick to the outer membrane of a cell. The virus can then infect the host cell and start the process of reproduction – making more copies of itself. The NA protein is required for the virus to exit the host cell and go on to infect other cells. Different influenza viruses have different combinations of hemagglutinin and neuraminidase proteins, hence the numbering. For example, the Type A virus that caused the outbreaks in the 1918 pandemic was called H1N1.

Inside the influenza virus, there are there are eight pieces (segments) of RNA, hence the fact that influenza is an RNA virus. Some viruses have DNA while others have RNA. The 8 segments of RNA provide the information that is required for making new copies of the virus. Each of these segments provides the instructions for making one or more proteins of the virus (eg. segment 4 contains the instructions to make the HA protein).


The 8 segments of RNA in influenza. Source: URMC

The Influenza virus is one of the most changeable viruses we are aware of, which makes it such a tricky beast to deal with. Influenza uses two techniques to change over time. They are called shift and drift.

Shifting is an sudden change in the virus, which produces a completely new combination of the HA and NA proteins. Virus shift can take place when a person or animal is infected with two different subtypes of influenza. When new viral particles are generated inside the cell, there is a mix of both subtypes of virus which gives rise to an all new type of virus.


An example of viral shift. Source: Bcm

Drifting is the process of random genetic mutation. Gradual, continuous, spontaneous changes that occur when the virus makes small “mistakes” during the replication of its RNA. These mistakes can results in a slight difference in the HA or NA proteins, and although those changes are small, they can be significant enough that the human immune system will no longer recognise and attack the virus. This is why you can repeatedly get the flu and why flu vaccines must be administered each year to combat new forms of circulating influenza virus.

What is a flu jab exactly?

Seasonal flu vaccination is a treatment that is given each year to minimise the risk of being infected by an influenza virus.

The ‘seasonal’ part of the label refers to the fact that the flu vaccine changes each year. Most flu vaccines target three strains of the viruses (and are thus called ‘Trivalent flu vaccines’) which are selected each year based on data collected by various health organisations around the world.

The three chosen viruses for a particular year are traditionally injected into and grown in hens’ eggs, then harvested and purified before the viral particles are chemically deactivated. The three dead viruses are then pooled together and packaged as a vaccine. As you can see in the image below, the process of vaccine production is laborious and takes a full year:


The process of vaccine production. Source: Linkedin

By injecting people with the dead viruses from three different strains of the influenza virus, however, the immune system has the chance to build up a defence against those viruses without the risk of the individual becoming infected (the dead viruses in the vaccine can not infect cells).

Flu vaccines cause the immune system to produce antibodies which are used by the immune system to help defend the body against future attacks from viruses. These antibodies generally take about two weeks to develop in the body after vaccination.

As we have said most injected flu vaccines protect against three types of flu virus. Generally each of the three viruses is taken from the following strains:

  • Influenza A (H1N1) – the strain of flu that caused the swine flu pandemic in 2009.
  • Influenza A (H3N2) – a strain of flu that mainly affects the elderly and people at risk with long term health conditions. In 2016/17 the vaccine contains an A/Hong Kong/4801/2014 H3N2-like virus.
  • Influenza B – a strain of flu that particularly affects children. In 2016/17 the vaccine contains B/Brisbane/60/2008-like virus.

How effective are the vaccines?

Well, it really depends on which strains of influenza are going to affect the most people each year, and this can vary greatly. Overall, however, research from the Centers for Disease Control and Prevention (or CDC) suggests that the seasonal flu vaccine reduces the chance of getting sick by approximately 50% (Source). Not bad when you think about it.

Ok, so are there actually any connections between influenza and Parkinson’s disease?

This question is up for debate.

There are certainly some tentative associations between influenza and Parkinson’s disease. Early on, those connections were coincidental, but more recently research is suggesting that there could be a closer relationship.


Between January 1918 and December 1920 there were two outbreaks of an influenza virus during an event that became known as the 1918 flu pandemic. Approximately 500 million people across the globe were infected by the H1N1 influenza virus, and this resulted in 50 to 100 million deaths (basically 3-5% of the world’s population). Given that is occurred during World War 1, censors limited the media coverage of the pandemic in many countries in order to maintain morale. The Spanish media were not censored, however, and this is why the 1918 pandemic is often referred to as the ‘Spanish flu’.


1918 Spanish flu. Source: Chronicle

At the same time that H1N1 was causing havoc, a Romanian born neurologist named Constantin von Economo reported a number of unusual symptoms which were referred to as encephalitis lethargica (EL). This disease left victims in a statue-like condition, speechless and motionless.


Constantin von Economo. Source: Wikipedia

By 1926, EL had spread around the world, with nearly five million people being affected. Many of those who survived never returned to their pre-existing state of health. They were left frozen in an immobile state.


An individual with encephalitis lethargica. Source: Baillement

Historically, it was believed that EL was caused by the influenza virus from the 1918 Spanish influenza pandemic. This was largely due to a temporal association (things happening at approximately the same time) and the finding of influenza antigens in some of the suffers of EL (Click here to read more about this).

And then there were also the observations of Dr Oliver Sacks:


Amazing guy! Dr Oliver Sacks. Source: Pensologosou

During the late 1960s, while employed as a neurologist at Beth Abraham Hospital’s chronic-care facility in New York, Dr Sacks began working with a group of survivors of EL, who had been left immobile by the condition. He treated these individuals with L-dopa (the standard treatment for Parkinson’s disease now, but it was still experimental at the time) and he observed them become miraculously reanimated. The sufferers went from being completely motionless to suddenly active and mobile. Unfortunately the beneficial effects were very short lived.

You may be familiar with Dr Sack’s book about his experience of treating these patients. It is called ‘Awakenings’ and it was turned into a film starring actors Robin Williams and Robert De Niro.


Robin Williams and Robert De Niro in Awakenings. Source: Pinterest

More recent, postmortem analysis of the brains of EL patients found an absence of influenza RNA – click here for more on this), which has led many researchers to simply reject the association between influenza and EL. The evidence supporting this rejection, however, has also been questioned (click here to read more on this), leaving the question of an association between influenza and EL still open for debate.

I think it’s fair to say that we genuinely do not know what caused EL. Whether it was influenza or not is still be undecided.

Ok, so that was the coincidental evidence. Has there been a more direct connection between influenza and Parkinson’s disease?

This is Dr Richard J Smeyne:


Source: Researchgate

Nice guy.

He is a research faculty member in the Department of Developmental Neurobiology at St. Jude Children’s Research Hospital (Memphis, Tennessee).

He has had a strong interest in what role viruses like influenza could be playing in the development of Parkinson’s disease, and his research group has published several interesting research reports on this topic, including:


Title: Highly pathogenic H5N1 influenza virus can enter the central nervous system and induce neuroinflammation and neurodegeneration.
Author: Jang H, Boltz D, Sturm-Ramirez K, Shepherd KR, Jiao Y, Webster R, Smeyne RJ.
Journal: Proc Natl Acad Sci U S A. 2009 Aug 18;106(33):14063-8.
PMID: 19667183                 (This article is OPEN ACCESS if you would like to read it)

Dr Smeyne and his colleagues found in this study that when they injected the highly infectious A/Vietnam/1203/04 (H5N1) influenza virus into mice, the virus progressed from the periphery (outside the brain) into the brain itself, where it induced Parkinson’s disease-like symptoms.

The virus also caused a significant increase in the accumulation of the Parkinson’s disease-associated protein Alpha Synuclein. In addition, they witnessed the loss of dopamine neurons in the midbrain of the mice at 60 days after the infection – that cell loss resembling what is observed in the brains of people with Parkinson’s disease.

Naturally this got the researchers rather excited!

In a follow up study on H5N1, however, these same researchers found that the Parkinson’s disease-like symptoms that they observed were actually only temporary:


Title: Inflammatory effects of highly pathogenic H5N1 influenza virus infection in the CNS of mice.
Authors: Jang H, Boltz D, McClaren J, Pani AK, Smeyne M, Korff A, Webster R, Smeyne RJ.
Journal: Journal for Neuroscience, 2012 Feb 1;32(5):1545-59.
PMID: 22302798                   (This article is OPEN ACCESS if you would like to read it)

Dr Smeyne and colleagues repeated the 2009 study and had a closer look at what was happening to the dopamine neurons that were disappearing at 60 days post infection with the virus. When they looked at mice at 90 days post infection, they found that the number of dopamine neurons had returned to their normal number. This pattern was also observed in a region of the brain called the striatum, where the dopamine neurons release their dopamine. The levels of dopamine dropped soon after infection, but rose back to normal by 90 days post infection.

How does that work?

The results suggest that rather than developing new dopamine neurons in some kind of miraculous regenerative process, the dopamine neurons that were infected by the virus simply stopped producing dopamine while they dealt with the viral infection. Once the crisis was over, the dopamine neurons went back to life as normal. And because the researcher use chemicals in the production of dopamine to identify the dopamine neurons, they mistakenly thought that the cells had died when they couldn’t see those chemicals.

One interesting observation from the study was that H5N1 infection in mice induced a long-lasting inflammatory response in brain. The resident helper cells, called microglia, became activated by the infection, but remained active long after the dopamine neurons returned to normal service. The investigators speculated as to whether this activation may be a contributing factor in the development of neurodegenerative disorders.

And this is an interesting idea.

In a follow up study, they investigated this further by looking another influenza viruse that doesn’t actually infect cells in the brain:


Title: Induction of microglia activation after infection with the non-neurotropic A/CA/04/2009 H1N1 influenza virus.
Author: Sadasivan S, Zanin M, O’Brien K, Schultz-Cherry S, Smeyne RJ.
Journal: PLoS One. 2015 Apr 10;10(4):e0124047.
PMID: 25861024                (This article is OPEN ACCESS if you would like to read it)

In this study, a different type of influenza (H1N1) was tested, and while it did not infect the brain, it did cause the microglia cells to flare up and become activated. And again, this activation was sustained for a long period after the infection (at least 90 days).

This is a really interesting finding and relates to the idea of a “double hit” theory of Parkinson’s disease, in which the virus doesn’t necessarily cause Parkinson’s disease but may play a supplemental or distractionary role, grabbing the attention of the immune system while some other toxic agent is also attacking the body. Or perhaps simply weakening the immune system by forcing it to fight on multiple fronts. Alone the two would not cause as much damage, but in combination they could deal a terrible blow.

So what was the flu vaccine research published last week?

Again, from Dr Smeyne’s research group, this report looked whether the combination of an influenza virus infection plus a toxic agent gave a worse outcome than just the toxic agent by itself. An interesting idea for a study, but then the investigators threw in another component: what effect would a influenza vaccine have in such an experiment. And the results are interesting:


Title: Synergistic effects of influenza and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) can be eliminated by the use of influenza therapeutics: experimental evidence for the multi-hit hypothesis
Authors: Sadasivan S, Sharp B, Schultz-Cherry S, & Smeyne RJ
Journal: npj Parkinson’s Disease 3, 18
PMID: N/A                    (This article is OPEN ACCESS if you would like to read it)

What the researchers found was that H1N1-infected mice that were treated with a neurotoxin (called MPTP – a toxin that specifically kills dopamine neurons) exhibit a 20% greater loss of dopamine neurons than mice that were treated with MPTP alone.

And this increase in dopamine neuron loss was completely eliminated by giving the mice the influenza vaccination. The researchers concluded that the results demonstrate that multiple insults (such as a viral infection and a toxin) can enhance the impact, and may even be significant in allowing an individual to cross a particular threshold for developing a disease.

It’s an intriguing idea.

Have epidemiologists (population data researchers) ever investigated a connection between Parkinson’s disease and influenza?

Good question.

And yes they have:

Title: Parkinson’s disease or Parkinson symptoms following seasonal influenza.
Authors: Toovey S, Jick SS, Meier CR.
Journal: Influenza Other Respir Viruses. 2011 Sep;5(5):328-33.
PMID: 21668692            (This article is OPEN ACCESS if you would like to read it)

In this first study, the researcher used the UK‐based General Practice Research Database to perform a case–control analysis (that means they compare an affected population with an unaffected ‘control’ population. They identified individual cases who had developed an ‘incident diagnosis’ of Parkinson’s disease or Parkinson’s like symptoms between 1994 and March 2007. For each of those case files identified, they matched them with at least four age matched control case files for comparative sake.

Their analysis found that the risk of developing Parkinson’s disease was not associated with previous influenza infections. BUT, they did find that Influenza was associated with Parkinson’s‐like symptoms such as tremor, particularly in the month after an infection. One can’t help but wonder if the dopamine neurons stopped producing dopamine during that period while they dealt with the viral infection.

But of course, I’m only speculating here… and it’s not like there was a second study suggesting that there is actually an association between Parkinson’s disease and influenza.

A year after that first study, a second study was published:

Journal: Association of Parkinson’s disease with infections and occupational exposure to possible vectors.
Authors: Harris MA, Tsui JK, Marion SA, Shen H, Teschke K.
Journal: Movement Disorder. 2012 Aug;27(9):1111-7.
PMID: 22753266

This second study reported that there is actually an association between Parkinson’s disease and influenza.

This investigation was also a case-control study, but it was based in British Columbia, Canada. The researchers recruited 403 individuals detected by their use of antiparkinsonian medications and matched them with 405 control subjects selected from the universal health insurance plan. Severe influenza was associated with Parkinson’s disease at an odds ratio of 2.01 (1 being no difference) and the range of the odds was 1.16-3.48. That’s pretty significant.

Interestingly, the effect is reduced when the reports of infection were restricted to those occurring within 10 years before diagnosis. This observation would suggest that early life infections may have more impact than previously thought.

Curiously, the researchers also found that exposure to certain animals (cats odds ration of 2.06; range 1.09-3.92) and cattle (2.23; range 1.22-4.09) was also associated with developing Parkinson’s disease.

Time to get rid of the pet cow.


Source: RSPB

Do any other neurodegenerative condition have associations with influenza?

In the limited literature search that we conducted, we only found reports dealing with influenza and Alzheimer’s disease.

Large studies suggest that Alzheimer’s is not associated with influenza (click here to read more on this). Interestingly, the Alzheimer’s associated protein beta amyloid has been shown to inhibit influenza A viruses (Click here to read that report), which may partly explain the lack of any association.

Influenza does have a mild association, however, with depression (Click here to see that report).

So what does it all mean?

A viral theory for Parkinson’s disease has existed since the great epidemic of 1918. Recent evidence points towards several viruses potentially having some involvement in the development of this neurodegenerative condition. And recent evidence suggests that influenza in particular could be particularly influential.

In 1938, Jonas Salk and Thomas Francis developed the first vaccine against flu viruses. It could be interesting for epidemiologists to go back and see if regular flu vaccination usage (if such data exists) reduces the risk of developing Parkinson’s disease.

But until such data is published, however, perhaps it would be wise to go and get a flu vaccine shot.

The banner for today’s post was sourced from the HuntingtonPost

New stem cell transplantation trial for Parkinson’s proposed in China


We have been contacted by some readers asking about a new stem cell transplantation clinical trial for Parkinson’s disease about to start in China (see the Nature journal editorial regarding this new trial by clicking here).

While this is an exciting development, there have been some concerns raised in the research community regarding this trial.

In today’s post, we will discuss what is planned and what it will mean for stem cell transplantation research.


Brain surgery. Source Bionews-tx

Parkinson’s disease is a progressive neurodegenerative condition.

This means that cells in the brain are slowly being lost over time. What makes the condition particularly interesting is that certain types of brain cells are more affected than others. The classic example of this is the dopamine neurons in an area of the brain called the substantia nigra, which resides in the midbrain.


The number of dark pigmented dopamine cells in the substantia nigra are reduced in the Parkinson’s disease brain (right). Source: Adapted from Memorangapp

Approximately 50% of the dopamine neurons in the midbrain have been lost by the time a person is diagnosed with Parkinson’s disease (note the lack of dark colouration in the substantia nigra of the Parkinsonian brain in the image above), and as the condition progresses the motor features – associated with the loss of dopamine neurons – gradually get worse. This is why dopamine replacement treatments (like L-dopa) are used for controlling the motor symptoms of Parkinson’s disease.

A lot of research effort is being spent on finding disease slowing/halting treatments, but these will leave many people who have already been diagnosed with Parkinson’s disease still dealing with the condition. What those individuals will require is a therapy that will be able to replace the lost cells (particularly the dopamine neurons). And researchers are also spending a great deal of time and effort on findings ways to do this. One of the most viable approaches at present is cell transplantation therapy. This approach involves actually injecting cells back into the brain to adopt the functions of the lost cells.

How does cell transplantation work?

We have discussed the history of cell transplantation in a previous post (Click here to read that post), and today we are simply going to focus on the ways this experimental treatment is being taken forward in the clinic.

Many different types of cells have been tested in cell transplantation experiments for Parkinson’s disease (Click here for a review of this topic), but to date the cells that have given the best results have been those dissected from the developing midbrain of aborted embryos.

This now old fashioned approach to cell transplantation involved dissecting out the region of the developing dopamine neurons from a donor embryo, breaking up the tissue into small pieces that could be passed through a tiny syringe, and then injecting those cells into the brain of a person with Parkinson’s disease.


The old cell transplantation process for Parkinson’s disease. Source: The Lancet

Critically, the people receiving this sort of transplant would require ‘immunosuppression treatment’ for long periods of time after the surgery. This additional treatment involves taking drugs that suppress the immune system’s ability to defend the body from foreign agents. This step is necessary, however, in order to stop the body’s immune system from attacking the transplanted cells (which would not be considered ‘self’ by the immune system), allowing those cells to have time to mature, integrate into the brain and produce dopamine.

The transplanted cells are injected into an area of the brain called the putamen. This is one of the main regions of the brain where the dopamine neurons of the substantia nigra release their dopamine. The image below demonstrates the loss of dopamine (the dark staining) over time as a result of Parkinson’s disease (PD):


The loss of dopamine in the putamen as Parkinson’s disease progresses. Source: Brain

In cell transplant procedures for Parkinson’s disease, multiple injections are usually made in the putamen, allowing for deposits in different areas of the structure. These multiple sites allow for the transplanted cells to produce dopamine in the entire extent of the putamen. And ideally, the cells should remain localised to the putamen, so that they are not producing dopamine in areas of the brain where it is not desired (possibly leading to side effects).


Targeting transplants into the putamen. Source: Intechopen

Postmortem analysis – of the brains of individuals who have previously received transplants of dopamine neurons and then subsequently died from natural causes – has revealed that the transplanted cells can survive the surgical procedure and integrate into the host brain. In the image below, you can see rich brown areas of the putamen in panel A. These brown areas are the dopamine producing cells (stained in brown). A magnified image of individual dopamine producing neurons can be seen in panel B:

Microsoft Word - Li W-Revision-Final.docx

Transplanted dopamine neurons. Source: Sciencedirect

The transplanted cells take several years to develop into mature neurons after the transplantation surgery, and the benefits of the transplantation technique may not be apparent for some time (2-3 years on average). Once mature, however, it has also been demonstrated (using brain imaging techniques) that these transplanted cells can produce dopamine. As you can see in the images below, there is less dopamine being processed (indicated in red) in the putamen of the Parkinsonian brain on the left than the brain on the right (several years after bi-lateral – both sides of the brain – transplants):


Brain imaging of dopamine processing before and after transplantation. Source: NIH

Sounds like a great therapy for Parkinson’s disease right?

So why aren’t we doing it???

Two reasons:

1. The tissue used in the old approach for cell transplantation in Parkinson’s disease was dissected from embryonic brains. Obviously there are serious ethical and moral problems with using this kind of tissue. There is also a difficult problem of supply: tissue from at least 3 embryos is required for transplanting each side of the brain (6 embryos in total). Given these issues, researchers have focused their attention on a less controversial and more abundant supply of cells: brain cells derived from embryonic stem cells (the new approach to cell transplantation).


Human embryonic stem cells. Source: Wikipedia

2. The second reason why cell transplantation is not more widely available is that in the mid 1990’s, the US National Institutes of Health (NIH) provided funding for the two placebo-controlled, double blind studies to be conducted to test the efficacy of the approach. Unfortunately, both studies failed to demonstrate any beneficial effects on Parkinson’s disease features.

In addition, many (15% – 50%) of transplanted subjects developed what are called ‘graft-induced dyskinesias’. This involves the subjects display uncontrollable/erratic movement (or dyskinesias) as a result of the transplanted cells. Interestingly, patients under 60 years of age did show signs of improvement on when assessed both clinically (using the UPDRS-III) and when assessed using brain imaging techniques (increased F-dopa uptake on PET).

Both of the NIH trials have been criticised by experts in the field for various procedural failings that could have contributed to the failures. But the overall negative results left a dark shadow over the technique for the better part of a decade. Researchers struggled to get funding for their research.

And this is the reason why many researchers are now urging caution with any new attempts at cell transplantation clinical trials in Parkinson’s disease – any further failures will really harm the field, if not kill if off completely.

Are there any clinical trials for cell transplantation in Parkinson’s disease currently being conducted?

Yes, there are currently two:

Firstly there is the Transeuro being conducted in Europe.


The Transeuro trial. Source: Transeuro

The Transeuro trial is an open label study, involving 40 subjects, transplanted in different sites across Europe. They will receive immunosuppression for at least 12 months post surgery, and the end point of the study will be 3 years post surgery, with success being based on brain imaging of dopamine release from the transplanted cells (PET scans). Based on the results of the previous NIH funding double blind clinical studies discussed above, only subject under 65 years of age have been enrolled in the study.


The European consortium behind the Transeuro trial. Source: Transeuro

In addition to testing the efficacy of the cell transplantation approach for Parkinson’s disease, another goal of the Transeuro trial is to optimise the surgical procedures with the aim of ultimately shifting over to an embryonic stem cells oriented technique in the near future with the proposed G-Force embryonic stem cell trials planned for 2018 (the Transeuro is testing the old approach to cell transplantation).

The second clinical study of cell transplantation for Parkinson’s disease is being conducted in Melbourne (Australia), by an American company called International Stem Cell Corporation.


This study is taking the new approach to cell transplantation, but the company is using a different type of stem cell to produce dopamine neurons in the Parkinsonian brain.

Specifically, the researchers will be transplanting human parthenogenetic stem cells-derived neural stem cells (hpNSC). These hpNSCs come from an unfertilized egg – that is to say, no sperm cell is involved. The female egg cell is chemically encouraged to start dividing and then it becoming a collection of cells that is called a blastocyst, which ultimately go on to contain embryonic stem cell-like cells.


The process of attaining embryonic stem cells. Source: Howstuffworks

This process is called ‘Parthenogenesis’, and it’s not actually as crazy as it sounds as it occurs naturally in some plants and animals (Click here to read more about this). Proponents of the parthenogenic approach suggest that this is a more ethical way of generating ES cells as it does not result in the destruction of a viable organism.

Regular readers of this blog will be aware that we are extremely concerned about this particular trial (Click here and here to read previous posts about this). Specifically, we worry that there is limited preclinical data from the company supporting the efficacy of these hpNSC cells being used in the clinical study (for example, researchers from the company report that the hpNSC cells they inject spread well beyond the region of interest in the company’s own published preclinical research – not an appropriate property for any cells being taken to the clinic). We have also expressed concerns regarding the researchers leading the study making completely inappropriate disclosures about the study while the study is ongoing (Click here to read more about this). Such comments only serve the interests of the company behind the study. And this last concern has been raised again with a quote in the Nature editorial about the Chinese trial:

“Russell Kern, chief scientific officer of the International Stem Cell Corporation in Carlsbad, California, which is providing the cells for and managing the Australian trial, says that in preclinical work, 97% of them became dopamine-releasing cells” (Source)

We are unaware of any preclinical data produced by Dr Kern and International Stem Cell Corporation…or ANY other research lab in the world that has achieved 97% dopamine-releasing cells. We (and others) would be interested in learning more about Dr Kerns amazing claim.

The International Stem Cell Corporation clinical trial is ongoing. For more details about this second ongoing clinical trial, please click here.

So what do we know about the new clinical study?

The clinical trial (Titled: A Phase I/II, Open-Label Study to Assess the Safety and Efficacy of Striatum Transplantation of Human Embryonic Stem Cells-derived Neural Precursor Cells in Patients With Parkinson’s Disease) will take place at the First Affiliated Hospital of Zhengzhou University in Henan province.

The researchers are planning to inject neuronal-precursor cells derived from embryonic stem cell into the brains of individuals with Parkinson’s disease. They have 10 subjects that they have found to be well matched to the cells that they will be injecting, which will help to limit the chance of the cells being rejected by the body.

In testing the safety and efficacy of these cells, the trial will have two primary outcome measures:
  1. Incidence of treatment-emergent adverse events, as assessed by brain imaging and blood examination at 6 months post transplant.
  2. Number of subjects with adverse events (such as the evidence of transplant failure or rejection)

In addition to these, there will also be a series of secondary outcome measures, which will include:

  1. Change in Unified Parkinson’s Disease Rating Scale (UPDRS) score at 12 months post surgery, when compared to baseline scores. Each subject was independently rated by two observers at each study visit and a mean score was calculated for analysis.
  2. Change in DATscan brain imaging at 12 months when compared to a baseline brain scan taken before surgery. DATscan imaging provides an indication of dopamine processing.
  3. Change in Hoehn and Yahr Stage at 12 months, compared to baseline scores. The Hoehn and Yahr scale is a commonly used system for Parkinson’s disease.

The trial will be a single group, non-randomized analysis of the safety and efficacy of the cells. The estimated date of completion is December 2020.

Why are some researchers concerned about the study?

Professor Qi Zhou, a stem-cell specialist at the Chinese Academy of Sciences Institute of Zoology will be leading the study and he has a REALLY impressive track record in the field of stem cell biology. His team undertaking this study have a great deal of experience working with embryonic stem cells, having published some extremely impressive research on this topic. But, (and it’s a big but) they have published a limited amount of research in peer-reviewed journals on cell transplantation in models of Parkinson’s disease. Lorenz Studer is one of the leading scientists in this field, was quoted in an editorial in the journal Nature this week:

“Lorenz Studer, a stem-cell biologist at the Memorial Sloan Kettering Cancer Center in New York City who has spent years characterizing such neurons ahead of his own planned clinical trials, says that “support is not very strong” for the use of precursor cells. “I am somewhat surprised and concerned, as I have not seen any peer-reviewed preclinical data on this approach,” he says.” (Source)

In addition to the lack of published research by the team undertaking the trial, the research community is also worried about the type of cells that are going to be transplanted in this clinical trial. Most of the research groups heading towards clinical trials in this area are all pushing embryonic stem cells towards a semi-differentiated state. That is, they are working on recipes that help the embryonic stem cells grow to the point that they have almost become dopamine neurons. Prof Zhou and his colleagues, however, are planning to transplant a much less differentiated type of cell called a neural-precursor cell in their transplants.


Neuronal-precursor cells. Source: Wired

Neuronal-precursors are very early stage brain cells. They are most likely being used in the study because they will survive the transplantation procedure better than a more mature neurons which would be more sensitive to the process – thus hopefully increasing the yield of surviving cells. But we are not sure how the investigators are planning to orient the cells towards becoming dopamine neurons at such an early stage of their development. Neuronal-precursors could basically become any kind of brain cell. How are the researchers committing them to become dopamine neurons?

Are these concerns justified?

We feel that there are justified reasons for concern.

While Prof Zhou and his colleagues have a great deal of experience with embryonic stem cells and have published very impressive research on that topic, the preclinical data for this trial is limited. In 2015, the research group published this report:

Title: Lmx1a enhances the effect of iNSCs in a PD model
Authors: Wu J, Sheng C, Liu Z, Jia W, Wang B, Li M, Fu L, Ren Z, An J, Sang L, Song G, Wu Y, Xu Y, Wang S, Chen Z, Zhou Q, Zhang YA.
Journal: Stem Cell Res. 2015 Jan;14(1):1-9.
PMID: 25460246              (This article is OPEN ACCESS if you would like to read it)

In this study, the researchers engineered embryonic stem cells to over-produce a protein called LMX1A to help produce dopamine neurons. LMX1A is required for the development of dopamine neurons (Click here to read more about this). The investigators then grew these cells in cell culture and compared their ability to develop into dopamine neurons against embryonic stem cells with normal levels of LMX1A. After 14 days in cell culture, 16% of the LMX1A cells were dopamine neurons, compared to only 5% of the control cells.

When the investigators transplanted these cells into a mouse model of Parkinson’s disease, they found that the behavioural recovery in the mice did not differ from the control injected mice, and when they looked at the brains of the mice 11 weeks after transplantation “very few engrafted cells had survived”.

In addition to this previously published work, the Chinese team do have unpublished research on 15 monkeys that have undergone the neuronal-precursor cell transplantation procedure having had Parkinson’s disease induced using a neurotoxin. The researchers have admitted that they initially did not see any improvements in movement (which is expected given the slow maturation of the cells). At the end of the first year, however, they examined the brains of some of the monkeys and they found that the transplanted stem cells had turned into dopamine-releasing cells (exactly what percentage of the cells were dopamine neurons is yet to be announced). The monkey study has been running for several years now and they have seen a 50% improvement in the motor ability of the remaining monkeys, supported by brain imaging data. The publication of this research is in preparation, but it probably won’t be available until after the trial has started.

So yes, there is a limited amount of preclinical research supporting the clinical trial.

As for concerns regarding the type of cells that are going to be transplanted:

Embryonic stem cells have robust tumour forming potential. If you inject them into the brain of mice, there is the potential for them to develop into dopamine neurons, but also tumours:

Title: Embryonic stem cells develop into functional dopaminergic neurons after transplantation in a Parkinson rat model
Authors: Bjorklund LM, Sánchez-Pernaute R, Chung S, Andersson T, Chen IY, McNaught KS, Brownell AL, Jenkins BG, Wahlestedt C, Kim KS, Isacson O.
Journal: Proc Natl Acad Sci U S A. 2002 Feb 19;99(4):2344-9.
PMID: 11782534               (This article is OPEN ACCESS if you want to read it)

In this study, the researchers found that of the twenty-five rats that received embryonic stem cell injections into their brains to correct the modelled Parkinson’s disease, five rats died before completed behavioural assessment and the investigators found teratoma-like tumours in their brains – less than 16 weeks after the cells had been transplanted.


A teratoma (white spot) inside a human brain. Source: Radiopaedia

Given this risk of tumour formation, research groups in the cell transplantation field have been trying to push the embryonic stem cells as far away from their original pluripotent state and as close to a dopamine fate as possible without producing mature dopamine neurons which will not survive the transplantation procedure very well.

Prof Zhou’s less mature neuronal-precursor cells are closer to embryonic stem cells than dopamine neurons on this spectrum than the kinds of cells other research groups are testing in cell transplantation experiments. As a result, we are curious to know what precautions the investigators are taking to limit the possibility of an undifferentiated, still pluripotent embryonic stem cell from slipping into this study (the consequences could be disastrous). And given their results from the LMX1A study described above, we are wondering how they are planning to push the cells towards a dopamine fate. If they do not have answers to this issues, they should not be rushing to the clinic with these cells.

So yes, there are reasons for concern regarding the cells that the researchers plan to use in this clinical trial.

And, as with the International Stem Cell Corporation stem cell trial in Australia, we also worry that the follow up-period (or endpoint in the study) of 12 months is not long enough to determine the efficacy of these cells in improving Parkinson’s rating scores and brain imaging results. All of the previous clinical research in this field indicates that the transplanted cells require years of maturation before their dopamine production has an observable impact on the participant. Using 12 months as an end point for this study is tempting a negative result when the long term outcome could be positive.

As we mentioned above, any negative outcomes for these studies could have dire consequences for the field as a whole.

So what does it all mean?

Embryonic stem cells hold huge potential in the field of regenerative medicine. Their ability to become any cell type in the body means that if we can learn how to control them correctly, these cells could represent a fantastic new tool for future cell replacement therapies in conditions like Parkinson’s disease.

Strong demand for such therapies from groups like the Parkinsonian community, has resulted in research groups rushing to the clinic with different approaches using these cells. Concerns as to whether such approaches are ready for the clinic are warranted, if only because mistakes by individual research groups/consortiums in the past have caused delays for everyone in the field.

While China is very keen (and should be encouraged) to take bold steps in its ambition to be a world leader in this field, open and transparent access to extensive preclinical research would help assuage concerns within the research community that prudent care is being taken heading forward.

We’ll keep you aware of developments in this clinical trial.

EDITORIAL NOTE No.1 – It is important for all readers of this post to appreciate that cell transplantation for Parkinson’s disease is still experimental. Anyone declaring otherwise (or selling a procedure based on this approach) should not be trusted. While we appreciate the desperate desire of the Parkinson’s community to treat the disease ‘by any means possible’, bad or poor outcomes at the clinical trial stage for this technology could have serious consequences for the individuals receiving the procedure and negative ramifications for all future research in the stem cell transplantation area. 

EDITORIAL NOTE No.2 – the author of this blog is associated with research groups conducting the current Transeuro transplantation trials and the proposed G-Force embryonic stem cell trials planned for 2018. He has endeavoured to present an unbiased coverage of the news surrounding the current clinical trials, though he shares the concerns of the Parkinson’s scientific community that the research supporting the current Australian trial is lacking in its thoroughness and will potentially jeopardise future work in this area. He is also concerned by the lack of peer-reviewed published research on cell transplantation in models of Parkinson’s disease for the proposed clinical studies in China. 

The banner for today’s post was sourced from Ozy

Oleuropein – “surely the richest gift of heaven?”


The title of this post is a play on a Thomas Jefferson quote (“the olive tree is surely the richest gift of heaven“). Jefferson, the third President of the United States (1801 to 1809), was apparently quite the lover of food. During the Revolutionary War, while he was a U.S. envoy to France, Jefferson travelled the country. In Aix-en-Provence, he developed an admiration for olive trees, calling them “the most interesting plant in existence”.

Being huge food lovers ourselves, we here at the SoPD wholeheartedly agree with Jefferson. But we also think that olives are interesting for another reason:

They contain a chemical called Oleuropein.

In today’s post we’ll explore what is known about this chemical and discuss what it could mean for Parkinson’s disease.


Olives. Source: Gardeningknowhow

The olive, also known by the botanical name ‘Olea europaea,’ is an evergreen tree that is native to the Mediterranean, Asia and Africa, but now found around the world. It has a rich history of economic and symbolic importance within western civilisation. And the fruit of the tree also tastes good, either by themselves or in a salad or pasta dish.

Traditional diets of people living around the Mediterranean sea are very rich in extra-virgin olive oil. Olives are an excellent source of ‘good’ fatty acids (monounsaturated and di-unsaturated), antioxidants and vitamins. Indeed, research has shown that the traditional Mediterranean diet reduces the risk of heart disease (Click here to read more on this).


Olive oil. Source: Bonzonosvilla

There are also chemicals within the olive fruit that may have very positive benefits for Parkinson’s disease.

But before you rush out and gorge yourself on olives, we have one small piece of advice:

The chemical is called Oleuropein, and it is usually removed from olives due to its bitterness.

What is Oleuropein?

Oleuropein is a ‘phenylethanoid’ – a type of phenolic compound that is found in the leaf and the fruit of the olive. Phenolic compounds are produced by plants as a protective measure against different kinds of stress.


Oleuropein. Source: Wikipedia

The main phenolic compounds found in olives are hydroxytyrosol and oleuropein – both of which give extra-virgin olive oil its bitter taste and both have demonstrated neuroprotective effects.

More research has been done on oleuropein so we will focus on it here (for more on hydroxytyrosol – please click here).

Oleuropein has been found to have many interesting properties, such as:


The many properties of oleuropein. Source: Mdpi

What neuroprotective research has been done on Oleuropein?

Thus far, most of the research addressing this question has been conducted on models of Alzheimer’s disease. The first study


Title: Oleuropein aglycone protects transgenic C. elegans strains expressing Aβ42 by reducing plaque load and motor deficit.
Authors: Diomede L, Rigacci S, Romeo M, Stefani M, Salmona M.
Journal: PLoS One. 2013;8(3):e58893.
PMID: 23520540                 (This article is OPEN ACCESS if you would like to read it)

The Italian researchers who conducted this study treated a microscopic worm model of Alzheimer’s disease with oleuropein aglycone. We should not that oleuropein aglycone is a hydrolysis product of oleuropein (a hydrolysis product is a chemical compound that is broken apart by the addition of water). The microscopic worm used in the study are called Caenorhabditis elegans:


Caenorhabditis elegans – cute huh? Source: Nematode

Caenorhabditis elegans (or simply C. Elegans) are tiny creatures that are widely used in biology because they can be easily genetically manipulated and their nervous system is very simple and well mapped out (they have just 302 neurons and 56 glial cells!). The particular strain of C. elegans used in this first study produced enormous amounts of a protein called Aβ42.

Amyloid beta (or Aβ) is the bad boy/trouble maker of Alzheimer’s disease; considered to be critically involved in the condition. A fragment of this protein (called Aβ42) begins clustering in the brains of people with Alzheimer’s disease. This clustering of Aβ42 goes on to form the plaques that are so characteristic of the Alzheimer’s affected brain.

The Italian researchers conducting this study had previously shown that oleuropein can inhibit the ability of Aβ42 to aggregate in cells growing in culture dishes (Click here to read more about that study), and they wanted to see if oleuropein had the same properties in actual live animals. So they chose the C. Elegans that had been genetically engineered to produce a lot of Aβ42 to test this idea.

In the C. Elegans that produce a lot of Aβ42 gradually become paralysed and their lives are shortened. By treating these worms with oleuropein, however, the Italian researchers found that there was less aggregation of Aβ42 (though the levels of the protein stayed the same), resulting in less plaque formation, and improved mobility (>50% reduction in paralysis) and survival compared to untreated Aβ42 producing C. Elegans.

Encouraged by this result, the researchers next moved on to studies in mice:


Title: The polyphenol oleuropein aglycone protects TgCRND8 mice against Aß plaque pathology.
Authors: Grossi C, Rigacci S, Ambrosini S, Ed Dami T, Luccarini I, Traini C, Failli P, Berti A, Casamenti F, Stefani M.
Journal: PLoS One. 2013 Aug 8;8(8):e71702.
PMID: 23951225                   (This article is OPEN ACCESS if you would like to read it)

For this study, the Italian researchers used the genetically engineered TgCRND8 mice. These mice have a mutant form of amyloid precursor protein (which, similar to Aβ42, is associated with Alzheimer’s disease). In the brains of these mice, amyloid clustering begins at 3 months of age, and dense plaques are evident from 5 months of age. The mice also exhibit a clear learning impairment from 3 months of age.

By treating these mice with oleuropein aglycone, the researchers observed a remarkable reduction in plaques in the brain, and those that were present appeared less compact and “fluffy” (their very technical description, not ours). In addition, there was a reduction in the activation of astrocytes and microglia (the helper cells in the brain), indicating a healthier environment.

These same researchers have observed the same results in a rat model of Alzheimer’s disease in a report published the next year (Click here to read more about this).

Interestingly, the oleuropein treated TgCRND8 mice also displayed a major increase in autophagy activity. As we discussed in our previous post (Click here to read that post), autophagy is the rubbish disposal/recycling system of each cell, and increasing the activity of this system can help to keep cells health (particularly if there is a lot of a genetically engineered protein present!).

The Italian researchers repeated this study, and published the results this year, with an interesting twist:


Title: Oleuropein aglycone and polyphenols from olive mill waste water ameliorate cognitive deficits and neuropathology.
Authors: Pantano D, Luccarini I, Nardiello P, Servili M, Stefani M, Casamenti F.
Journal: Br J Clin Pharmacol. 2017 Jan;83(1):54-62.
PMID: 27131215

In this study, the researchers tested the same genetically engineered mice, but with two different treatments:

  1.  Two much lower doses of oleuropein (4 and 100 times lower)
  2.  A mixture of polyphenols from olive mill concentrated waste water

The lowest dose of oleuropein (100 times less oleuropein than the previous study) did not provide any significant improvements for the mice, but the intermediate dose (only 4 times less oleuropein than the previous study) did provide significant benefits. These result indicate that there is a dose-dependent range to the beneficial properties of oleuropein.

The researchers also observed very similar beneficial effects from the mice drinking a mixture of polyphenols from olive mill concentrated waste water. Given these results, the investigators are now seeking to design appropriate conditions to perform a clinical trial to assess better the possible use of oleuropein (or a mix of olive polyphenols) against Alzheimer’s disease.

Ok, but what research has been done with oleuropein and Parkinson’s disease?

Unfortunately, not much.

A research group in Iran has looked at the effect of oleuropein in aged rodents and found an interesting result:

Title: Antioxidant role of oleuropein on midbrain and dopaminergic neurons of substantia nigra in aged rats.
Authors: Sarbishegi M, Mehraein F, Soleimani M.
Journal: Iran Biomed J. 2014;18(1):16-22.
PMID: 24375158                 (This article is OPEN ACCESS if you would like to read it)

In this study, the investigators took twenty aged rats (18-month-old) and randomly assigned them to two groups: a treatment group (which received a daily dose of 50 mg/kg of oleuropein for 6 months) and a control group (which received just water). Following these treatments, the investigators found an increase in the activity of anti-oxidant agents (such as superoxide dismutase, catalase and glutathione) in the treatment group compared to control group. The treated rats also had significantly more dopamine neurons in the region of the brain affected by Parkinson’s disease (the substantia nigra). The investigators concluded that oleuropein consumption in a daily diet may be useful in reducing oxidative stress damage by increasing the antioxidant activity in the brain.

This first study was followed more recently by a report from a group in Quebec (Canada) who investigated oleuropein use in a cell culture model of Parkinson’s disease:

Title: Oleuropein Prevents Neuronal Death, Mitigates Mitochondrial Superoxide Production and Modulates Autophagy in a Dopaminergic Cellular Model.
Authors: Achour I, Arel-Dubeau AM, Renaud J, Legrand M, Attard E, Germain M, Martinoli MG.
Journal: Int J Mol Sci. 2016 Aug 9;17(8).
PMID: 27517912              (This article is OPEN ACCESS if you would like to read it)

The researcher conducting this study wanted to determine if oleuropein could prevent neuronal degeneration in a cellular model of Parkinson’s disease. They exposed cells to the neurotoxin 6-hydroxydopamine (6-OHDA) and then investigated mitochondrial oxidative stress and autophagy.

What is mitochondrial oxidative stress?

Mitochondria are the power house of each cell. They keep the lights on. Without them, the lights go out and the cell dies.


Mitochondria and their location in the cell. Source: NCBI

Oxidative stress results from too much oxidation. Oxidation is the loss of electrons from a molecule, which in turn destabilises the molecule. Think of iron rusting. Rust is the oxidation of iron – in the presence of oxygen and water, iron molecules will lose electrons over time. Given enough time, this results in the complete break down of objects made of iron.


Rust, the oxidation of metal. Source: TravelwithKevinandRuth

The exact same thing happens in biology. Molecules in your body go through a similar process of oxidation – losing electrons and becoming unstable. This chemical reaction leads to the production of what we call free radicals, which can then go on to damage cells. A free radical is an unstable molecule – unstable because they are missing electrons.


How free radicals and antioxidants work. Source: h2miraclewater

In an unstable format, free radicals bounce all over the place, reacting quickly with other molecules, trying to capture the much needed electron to re-gain stability. Free radicals will literally attack the nearest stable molecule, to steal an electron. This leads to the “attacked” molecule becoming a free radical itself, and thus a chain reaction is started. Inside a living cell this can cause terrible damage, ultimately killing the cell.

Now if this oxidative process starts in the mitochondria, it can be very bad for a cell.

And what is autophagy?

Yes, the researchers also looked at autophagy levels in their cells. Autophagy is an absolutely essential function in a cell. Without autophagy, old proteins and mitochondria will pile up making the cell sick and eventually it dies. Through the process of autophagy, the cell can break down the old protein, clearing the way for fresh new proteins to do their job.

Think of autophagy as the waste disposal/recycling process of the cell.


The process of autophagy. Source: Wormbook

Waste material inside a cell is collected in membranes that form sacs (called vesicles). These vesicles then bind to another sac (called a lysosome) which contains enzymes that will breakdown and degrade the waste material. The degraded waste material can then be recycled or disposed of by spitting it out of the cell.

Ok, so what did the researchers find?

Well, by pretreating the their cells with oleuropein 3 hours before exposing them to the neurotoxin, the investigators found a significant neuroprotective effect. There was a significant reduction in mitochondrial production of free radicals, and the investigators found an important role for oleuropein in the regulation of autophagy.

And the good news is that other research groups have observed similar beneficial effects of oleuropein in cell culture models of Parkinson’s disease (Click here to read more about that).

The bad news is: that is all the published research on oleuropein and Parkinson’s disease we could find (and we would be happy to be corrected on this if people are aware of other reports!).

So what does Oleuropein do in the brain?

This is a good question, but with so little research done in this area, it is hard to answer.

We know that oleuropein is well absorbed by the human body and that it is relatively stable (Click here to read more on this). In addition, it can cross the blood-brain-barrier – in rodents at least (Click here to read more on that).

Obviously (based on the research we described above), we know that oleuropein has anti-oxidant promoting activities. In addition, it appears to be doing something with regards to autophagy. And it may be regulating autophagy by acting as an inhibitor of mammalian target of rapamycin (mTOR) activation.

What is mTOR?

mTOR is a protein that binds with other proteins to form the nexus of a signalling pathway which integrates both intracellular and extracellular signals (such asnutrients, growth factors, and cellular energy status) and then serves as one of the central instructors of how the cell should respond.

For example, insulin can signal to mTOR the status of glucose levels in the body. mTOR also deals with infectious or cellular stress-causing agents, thus it could be involved in a cells response to conditions like Parkinson’s disease.


Factors that activate mTOR. Source: Selfhacked

One important property of mTOR is its ability to block autophagy (the recycling process of the cell that we discussed above). Recently, the Italian researchers whose work we reviewed above, found that oleuropein can activate autophagy by blocking the mTOR pathway:


Title: Oleuropein aglycone induces autophagy via the AMPK/mTOR signalling pathway: a mechanistic insight.
Authors: Rigacci S, Miceli C, Nediani C, Berti A, Cascella R, Pantano D, Nardiello P, Luccarini I, Casamenti F, Stefani M.
Journal: Oncotarget. 2015 Nov 3;6(34):35344-57.
PMID: 26474288                (This article is OPEN ACCESS if you would like to read it)

The researchers conducting this study found that treatment with oleuropein caused an increase in autophagy in both cell culture and in a mouse model of Alzheimer’s disease, and they demonstrated that it achieved this by blocking the mTOR pathway.

Has anyone ever looked at oleuropein in the clinic?

No, not to our knowledge (and we are happy to be corrected on this).

There have been six clinical trials of olive leaf extract (the majority of which is oleuropien), but none of them have been focused on any neurological conditions.


So oleuropein is safe then?

It is a widely available supplement that a lot of people use to help lower bad cholesterol and blood pressure, so yes it can be considered safe. But any decision to experiment with oleuropein should only be made in consultation with your regular medically trained physician.

Why? Because there are always caveats.

Importantly, individuals with low blood pressure and diabetes may suffer even lower blood pressure and blood glucose levels as a result of consumption of oleuropein. Oleuropein may also interact with other pharmaceutical drugs that are designed to lower blood pressure or regulate diabetes. Such interactions could be dangerous.

And this is a particularly important factor for Parkinson’s disease as up to 30% of people with Parkinson’s may be glucose intolerant (Click here to see our post on Parkinson’s & diabetes).

Those who experience symptoms such as headache, nausea, flu-like symptoms, fainting, dizziness, and other life threatening symptoms should medical attention immediately.

What does it all mean?

We are grateful to regular reader (Don) who brought oleuropein to our attention. It is a very interesting chemical and we are definitely intrigued by it. We would certainly like to see more research on oleuropein in models of Parkinson’s disease.

Attentive readers will have noticed that most of the research discussed above have been conducted in the last 5-10 years. This suggests that oleuropein research is still in its infancy, particularly with regards to research on neurological conditions. And we hope that by reporting on it here, we will be bringing it to the attention of researchers.

Oleuropein is extracted from all parts of the olive tree (the leaves, bark, root, and fruit). It forms part of the defence system of the olive tree against stress or infection. Perhaps we could apply some of its interesting properties to Parkinson’s disease.

EDITORIAL NOTE:  Under absolutely no circumstances should anyone reading the material on this website consider it medical advice. The information provided here is for educational purposes only. Before considering or attempting any change in your treatment regime, PLEASE consult with your doctor or neurologist. While some of the drugs and supplements discussed on this website are clinically available, they may have serious side effects. We urge caution and professional consultation before altering any treatment regime. SoPD can not be held responsible for any actions taken based on the information provided here. 

The banner for this post was sourced from jrbenjamin

James: That essay


In her excellent book – ‘The Enlightened Mr. Parkinson: The Pioneering Life of a Forgotten English Surgeon’ (Icon Books Ltd) – Dr Cherry Lewis wrote that the earliest reference to Mr James Parkinson’s ‘An Essay on the Shaking Palsy’ was an advert placed in the Morning Chronicle of Saturday 31st May (1817), under a list of books “published this day”.

Given this information, we searched the Britishnewspaperarchive online and captured the image presented above.

Today is the 200th anniversary of the publication of ‘An Essay on the Shaking Palsy’.

In this post, we continue our four part series on the man behind the disease by discussing the ‘Essay’ on the 200th anniversary of its publication.


The opening of Waterloo Bridge on the 18th of June 1817. Source: Thames

A few weeks before the opening of the Waterloo Bridge, James Parkinson published the booklet that would go on to immortalise him in the annals of medicine. An Essay on the Shaking Palsy, which spans 66 pages, was published by Sherwood, Neely and Jones of London, and printed by Whittingham and Rowland in 1817.

At the date of printing it sold for 3 shillings (approx. £9 or US$12).

Much has been written about the essay, and we here at the SoPD feel that we have little to actually add to the conversation. Thus our post today will simply provide an overview of the book (a highlights package, if you will), summarising it for those who do not have time to read its entirety (a full copy of the essay can be found by clicking here).


Source: Project Gutenberg

The Essay begins with a preface and is then divided into five chapters, labeled:






The preface

In the preface of the book, James gave his reasons for actually writing it. Basically, he wanted to make others aware of what he considered a previously un-described condition.

At the heart of the preface is a paragraph, which reads:

“The disease is of long duration: to connect, therefore, the symptoms which occur in its later stages with those which mark its commencement, requires a continuance of observation of the same case, or at least a correct history of its symptoms, even for several years. Of both these advantages the writer has had the opportunities of availing himself; and has hence been led particularly to observe several other cases in which the disease existed in different stages of its progress. By these repeated observations, he hoped that he had been led to a probable conjecture as to the nature of the malady, and that analogy had suggested such means as might be productive of relief, and perhaps even of cure, if employed before the disease had been too long established. He therefore considered it to be a duty to submit his opinions to the examination of others, even in their present state of immaturity and imperfection.”

At the end of the preface, James hopes that friends to humanity and medical science…might be excited to extend their researches to this malady”. And in that situation James would “think himself fully rewarded by having excited the attention of those, who may point out the most appropriate means of relieving a tedious and most distressing malady”. 

Chapter 1

In the first chapter, James begins with a description of the Shaking Palsy (or ‘Paralysis agitans’ as he called it), that resembles modern Parkinson’s disease almost perfectly:

“Involuntary tremulous motion, with lessened muscular power, in parts not in action and even when supported; with a propensity to bend the trunk forwards, and to pass from a walking to a running pace: the senses and intellects being uninjured.”

He then moves on to provide a breakdown of the features that make up this condition, which includes a history of tremor that takes into account the works of Aelius “Galen” GalenusSylvius de la Boë, and Johann Juncker.

James starts by noting the slow progress of the condition:

“So slight and nearly imperceptible are the first inroads of this malady, and so extremely slow is its progress, that it rarely happens, that the patient can form any recollection of the precise period of its commencement. The first symptoms perceived are, a slight sense of weakness, with a proneness to trembling in some particular part; sometimes in the head, but most commonly in one of the hands and arms.”

How familiar does this sound?

And please remember, James was describing this condition for the first time based only on his own observations of just six individuals (three from a distance). His attention to detail was amazing, taking into account so many different aspects of the condition (from the obvious motor features to issues with bowel movements). And he noted it all down in the essay.

He continues by describing the progress of the condition over time:

“But as the malady proceeds,….The propensity to lean forward becomes invincible, and the patient is thereby forced to step on the toes and fore part of the feet, whilst the upper part of the body is thrown so far forward as to render it difficult to avoid falling on the face.”

His description took into account the entire history of the condition, starting from the appearance of the first features and finishing with the late stages of the disease:

“As the disease proceeds towards its last stage, the trunk is almost permanently bowed, the muscular power is more decidedly diminished, and the tremulous agitation becomes violent….As the debility increases and the influence of the will over the muscles fades away, the tremulous agitation becomes more vehement. It now seldom leaves him for a moment;”

After describing the basic clinical appearance of the condition, James then immediately moves on to each of the six cases he based his description on.

Case I was the first encounter of this condition for James. It was also probably one of the case that James was most familiar with as he wrote “every circumstance occurred which has been mentioned in the preceding history”. In his writing of Case I, however, James was rather brief:

Case I

“The subject of this case was a man rather more than fifty years of age, who had industriously followed the business of a gardener, leading a life of remarkable temperance and sobriety. The commencement of the malady was first manifested by a slight trembling of the left hand and arm, a circumstance which he was disposed to attribute to his having been engaged for several days in a kind of employment requiring considerable exertion of that limb. Although repeatedly questioned, he could recollect no other circumstance which he could consider as having been likely to have occasioned his malady.”

The “next case” (as James wrote it, indicating that the cases are presented in chronological order), Case II, was a man that James casually met with in the street.

Case II

“It was a man sixty-two years of age; the greater part of whose life had been spent as an attendant at a magistrate’s office. He had suffered from the disease about eight or ten years. All the extremities were considerably agitated, the speech was very much interrupted, and the body much bowed and shaken. He walked almost entirely on the fore part of his feet, and would have fallen every step if he had not been supported by his stick. He described the disease as having come on very gradually,…”

Case II attributed his condition to his choice of lifestyle (“irregularities in mode of living and indulgence in spiritous liquors,”), which James did not give any credit. This was probably because much of the rest of the city partook in such a lifestyle without the emergence of the disease. Ever the humanitarian, though, James points towards the unfortunate situation that these individuals found themselves:

“He was the inmate of a poor-house of a distant parish, and being fully assured of the incurable nature of his complaint, declined making any attempts for relief.”

The third case was also “noticed casually in the street“. James did interact with the man though, determining that he had been a sailor who attributed his condition to having been for many months in a Spanish prison:

Case III.

“The subject…was a man of about sixty-five years of age, of a remarkable athletic frame. The agitation of the limbs, and indeed of the head and of the whole body, was too vehement to allow it to be designated as trembling. He was entirely unable to walk; the body being so bowed, and the head thrown so forward, as to oblige him to go on a continued run, and to employ his stick every five or six steps to force him more into an upright posture, by projecting the point of it with great force against the pavement.”

The 4th case was a gentleman (of about fifty-five years of age) who presented himself to James. He claimed that he had first experienced the trembling of the arms about five years before. In this case, we see the nature of the medical treatments during that period (that being a preference for blood letting):

Case IV.

“His application was on account of a considerable degree of inflammation over the lower ribs on the left side, which terminated in the formation of matter beneath the fascia. About a pint was removed on making the necessary opening; and a considerable quantity discharged daily for two or three weeks. On his recovery from this, no change appeared to have taken place in his original complaint; and the opportunity of learning its future progress was lost by his removal to a distant part of the country”

Case V was the subject that James had the least amount of information about and observed the gentleman only from a distance (it is curious to note that all of these cases were males – who have a higher risk of developing Parkinson’s disease – click here for more on this):

Case V.

“…one of the characteristic symptoms of this malady, the inability for motion, except in a running pace, appeared to exist in an extraordinary degree. It seemed to be necessary that the gentleman should be supported by his attendant, standing before him with a hand placed on each shoulder, until, by gently swaying backward and forward, he had placed himself in equipoise; when, giving the word, he would start in a running pace, the attendant sliding from before him and running forward, being ready to receive him and prevent his falling, after his having run about twenty paces”

Case VI may have been the individual that spurred James to write his essay as it was one “which presented itself to observation since those above-mentioned,”. Thus, James had the benefit of hindsight and all the information that he had gained from the previous cases, when he was confronted with Case VI and he could make a thorough study of the individual. In case VI, James also hints at the indiscriminate nature of the condition, afflicting people from all sorts of backgrounds.

Case VI.

“The gentleman who was the subject of it is seventy-two years of age. He has led a life of temperance, and has never been exposed to any particular situation or circumstance which he can conceive likely to have occasioned, or disposed to this complaint; which he rather seems to regard as incidental upon his advanced age, than as an object of medical attention….About eleven or twelve, or perhaps more, years ago, he first perceived weakness in the left hand and arm, and soon after found the trembling commence. In about three years afterwards the right arm became affected in a similar manner: and soon afterwards the convulsive motions affected the whole body, and began to interrupt the speech…Of late years the action of the bowels had been very much retarded;…”

James notes with Case VI that the gentleman had the capacity to temporarily control his situation by his own will:

“…he, being then just come in from a walk, with every limb shaking, threw himself rather violently into a chair, and said, ‘Now I am as well as ever I was in my life.’ The shaking completely stopped; but returned within two minutes”

At the end of the section on CaseVI, James notes some input from the wife of the gentleman:

“…if whilst walking he felt much apprehension from the difficulty of raising his feet, if he saw a rising pebble in his path? he avowed, in a strong manner, his alarm on such occasions; and it was observed by his wife, that she believed, that in walking across the room, he would consider as a difficulty the having to step over a pin”

Having finished reading Chapter 1, it is truly remarkable to recall that James was describing what he thought was a previously unrecognised condition. Remarkable because of the depth and scope he provides. It is difficult to put oneself in his shoes, given that we are now so familiar with the disease. But it does Mr Parkinson great credit both as a surgeon and a writer that what he is describing feels so familiar.

Chapter 2

Here James returns to the cardinal features of the condition as he sees them, starting with the tremor:

1. Involuntary tremulous motion, with lessened voluntary muscular power, in parts, not in action, and even supported.

In this first section, James breaks down the different types of tremor in an effort to better understand this condition he is describing.

“It is necessary that the peculiar nature of this tremulous motion should be ascertained, as well for the sake of giving to it its proper designation, as for assisting in forming probable conjectures, as to the nature of the malady, which it helps to characterise”

And again, James cites the works of Galen and Sylvius de la Boë.


Galen. Source: thefamouspeople

“The separation of palpitation of the limbs (Palmos of Galen, Tremor Coactus of de la Boë) from tremor, is the more necessary to be insisted on, since the distinction may assist in leading to a knowledge of the seat of the disease.”


de la Boë. Source: Wikipedia

James concludes that the tremor associated with his new condition is distinct given that the tremor is nearly constant or “induced immediately on bringing the parts into action”

The second characteristic feature of this newly described condition, according to James, is the gait and posture:

2. A propensity to bend the trunk forwards, and to pass from a walking to a running pace.

Here James discusses the works of François Boissier de Sauvages de Lacroix (1706 – 1767), a French physician and botanist who is credited with establishing a methodical nosology for diseases (a classification system).


de Sauvage. Source: Homeoint

“Mons. de Sauvages attributes this complaint to a want of flexibility in the muscular fibres. Hence, he supposes, that the patients make shorter steps, and strive with a more than common exertion or impetus to overcome the resistance; walking with a quick and hastened step, as if hurried along against their will”

It is a demonstration of Mr Parkinson’s studious nature and high general level of intelligence that he was so familiar with the works of de Sauvage – it is a simple task for us modern folk to simply ‘google’ anything we don’t know or are curious about. Where did James go to find his background research for his Esssay?

Having clearly outlined the features of the condition, James next moves to Chapter 3 where he attempts to differentiate this condition from other maladies.

Chapter 3

James did not want to have this new condition he was describing confused with other diseases, hence the meticulous description of the symptoms/features.

“…it is necessary to show that it is a disease which does not accord with any which are marked in the systematic arrangements of nosologists; and that the name by which it is here distinguished has been hitherto vaguely applied to diseases very different from each other, as well as from that to which it is now appropriated”

James’ choice of name for the new condition was ‘Shaking palsy’, but he noted that this label had been used several times before. For example, one Dr. Charlton had used the label in describing a particular case:

“Another case, which the Doctor designates as ‘A Shaking Palsy,’ apparently from worms, he describes thus, “A poor boy, about twelve or thirteen years of age, was seized with a Shaking Palsy. His legs became useless, and together with his head and hands, were in continual agitation; after many weeks trial of various remedies, my assistance was desired…His bowels being cleared, I ordered him a grain of Opium a day in the gum pill; and in three or four days the shaking had nearly left him.” By pursuing this plan, the medicine proving a vermifuge, he could soon walk, and was restored to perfect health”

Given the level of detail that James goes into in other chapters, it is fair to say that chapter 3 is light reading. But it finishes strong as James describes the truly distinguishing feature of his version of Shaking palsy – that being the resting state nature of the tremor:

“If the trembling limb be supported, and none of its muscles be called into action, the trembling will cease. In the real Shaking Palsy the reverse of this takes place, the agitation continues in full force whilst the limb is at rest and unemployed;”

And it was this feature for James that could be used to distinguish it from other conditions.

Chapter 4

In Chapter 4, James tries to understand the cause of the condition, but right up front he acknowledges that this is a rather difficult task:

“Unaided by previous inquiries immediately directed to this disease, and not having had the advantage, in a single case, of that light which anatomical examination yields, opinions and not facts can only be offered”

In addition, James notes that “Cases illustrative of the nature and cause of this malady are very rare”

He does an admirable job in his endeavour here, however, by looking at previously reported cases of other diseases that share some similarities with this new condition. And James actually describes cases that he himself has dealt with (albeit by informally), but he takes pains to point out that these cases are different to the new conditions that he is describing in this essay. For example:

“…the unhappy subject of this malady was casually met in the street, shifting himself along, seated in a chair; the convulsive motions having ceased, and the limbs having become totally inert, and insensible to any impulse of the will”

In this case, the man had been treated with mercury for a venereal infection (click here to read more about early mercury treatments) many years before, which had left him with convulsive movements restricted to the legs.

Using this case study approach, however, James proposes that the disease is targeting or affecting an area of the brain stem called the medulla oblongata (which is affected in Parkinson’s disease, and is actually not too far from the midbrain where the significant loss of the dopamine neurons gives rise to the motor features of Parkinson’s disease).


Location of the midbrain and medulla in the human brain. Source: Wikipedia

Chapter 5

In chapter 5, James expresses hope that a successful treatment is almost at hand:

“…there appears to be sufficient reason for hoping that some remedial process may ere long be discovered, by which, at least, the progress of the disease may be stopped”

Exactly 200 years on, I think it is fair to say that James was a bit too optimistic in nature, but we are certainly a lot closer now to stopping the disease than he was then.

James was instructive in how he thought it was best to attack the condition. He divides the condition into two halves, early and late, based on the spread of the motor features from individual limbs to other areas of the body. And he is rather certain that early diagnosis was essential if there was to be any chance of cure.

He also thought that the condition simply required some reverse engineering:

“…it seems as if we were able to trace the order and mode in which the morbid changes may proceed in this disease”

But his thoughts on how to treat the disease were largely based on the medical practises of the time (as they are today):

“…blood should be first taken from the upper part of the neck,…After which vesicatories should be applied to the same part, and a purulent discharge obtained by appropriate use of the Sabine Liniment; having recourse to the application of a fresh blister, when from the diminution of the discharging surface, pus is not secreted in a sufficient quantity”

He provides further thoughts on this treatment, but then offers the caveat that this is merely an opinion:

“Until we are better informed respecting the nature of this disease, the employment of internal medicines is scarcely warrantable;”

James also then comments on the insidious nature and the slow progress of the disease, as it:

“Seldom occurring before the age of fifty, and frequently yielding but little inconvenience for several months, it is generally considered as the irremediable diminution of the nervous influence, naturally resulting from declining life; and remedies therefore are seldom sought for”

And this leaves the sufferer focusing on:

“The weakened powers of the muscles in the affected parts is so prominent a symptom, as to be very liable to mislead the inattentive, who may regard the disease as a mere consequence of constitutional debility. If this notion be pursued, and tonic medicines, and highly nutritious diet be directed, no benefit is likely to be thus obtained; since the disease depends not on general weakness, but merely on the interruption of the flow of the nervous influence to the affected parts”

This is very insightful of James. He understood that it was not the weakness felt in the muscles that was paramount in this condition, but rather a dysfunction in the brain.

He concludes the essay with the following:

“To such researches the healing art is already much indebted for the enlargement of its powers of lessening the evils of suffering humanity. Little is the public aware of the obligations it owes to those who, led by professional ardour, and the dictates of duty, have devoted themselves to these pursuits, under circumstances most unpleasant and forbidding. Every person of consideration and feeling, may judge of the advantages yielded by the philanthropic exertions of a Howard; but how few can estimate the benefits bestowed on mankind, by the labours of a Morgagni, Hunter, or Baillie.


Regarding the last line, I may be displaying my ignorance here with regards to ‘a Howard’, but I suspect James is referring to John Howard (1726 – 1790), an English philanthropist of James’ era:


John Howard. Source: Wikipedia

Although, “a Howard” is also an old slang term used to describe a man (any man) of great character!


Giovanni Battista MorgagniSource: Wikipedia

Giovanni Battista Morgagni (1682 – 1771) was an Italian anatomist, who is generally regarded as the father of modern anatomical pathology.


John Hunter. Source: Wikipedia

John Hunter (1728 – 1793) was a Scottish surgeon – one of the most distinguished scientists/surgeons of his day. He was an early advocate of careful observation and scientific method in medicine, and James personally learned a great deal from him. Between October 1785 and April 1786, James attended the evening lectures provided by Hunter. James wrote down the lectures verbatim (in shorthand) and his notes were later published by his son John (“Hunterian Reminiscences, Being The Substance Of A Course Of Lectures On The Principles And Practice Of Surgery Delivered By John Hunter In The Year 1785″ – a precious resource given that Hunter’s own notes were later destroyed by fire).

Matthew Baille FRS (1761-1823)

Matthew BaillieSource: Wikipedia

Matthew Baillie was another Scottish physician and pathologist. A pupil of his uncle, John Hunter (above), Ballie provided us with the first systematic study of pathology. James was certainly familiar with Ballie, as he cited his works.

For further reading on An Essay on the Shaking Palsy we recommend a review written by Prof Brian Hurwitz (King’s College London) called Urban Observation and Sentiment in James Parkinson’s Essay on the Shaking Palsy (1817) which provides fantastic insight into James, the age he lived in, the essay itself, and the reception of the essay (Click here to read that review).

This post was written in observation of the 200 year anniversary of the publishing of the Essay on the Shaking Palsy. It is part two in a four part series on the life of Mr James Parkinson (click here for part one). In the third instalment, we will look at his life’s work, before the fourth part looks at his final years and his legacy.

The banner for today’s post was sourced from the Britishnewspaperarchive

Sheffield: flies, fish and a Tigar


When people in England think of the city of Sheffield, quite often images of a great industrial past will come to mind.

They usually don’t think of the flies, fish and (yes) a Tigar (no, not a typo!) that are influencing Parkinson’s disease research in the city.

In today’s post we will look at how the re-invention of a city could have a major impact on Parkinson’s disease.


The industrial heritage of Sheffield. Source: SIMT

It is no under statement to say that the history of Sheffield – a city in South Yorkshire, England –  is forged in steel.

In his 1724 book, “A tour thro’ the whole island of Great Britain, the author Daniel Defoe wrote of Sheffield:

“Here they make all sorts of cutlery-ware, but especially that of edged-tools, knives, razors, axes, &. and nails; and here the only mill of the sort, which was in use in England for some time was set up, for turning their grindstones, though now ’tis grown more common”

Sheffield has a long history of metal work, thanks largely to its geology: The city is surrounded by fast-flowing rivers and hills containing many of the essential raw materials such as coal and iron ore.

And given this fortunate circumstance and an industrious culture, the city of Sheffield particularly prospered during the industrial revolution of the mid-late 1800s (as is evident from the population growth during that period).


The population of Sheffield over time. Source: Wikipedia

But traditional manufacturing in Sheffield (along with many other areas in the UK) declined during the 20th century and the city has been forced to re-invent itself in the early 21st century. And this time, rather than taking advantage of their physical assets, the city is focusing on its mental resources.

Great. Interesting stuff. Really. But what does this have to do with flies, fish and Parkinson’s disease???

Indeed. Let’s get down to business.


The Sheffield Institute for Translational Neuroscience (SITraN) was officially opened in 2010 by Her Majesty The Queen. It is the first European Institute purpose-built and dedicated to basic and clinical research into Motor Neuron Disease as well as related neurodegenerative disorders such as Parkinson’s and Alzheimer’s disease.

Since its opening, the institute has published some pretty impressive research, particularly in the field of Parkinson’s disease.

And here is where we get to the flies:


Pink flies. Source: Wallpapersinhq

We have previously discussed “Pink” flies and their critical role in Parkinson’s research (Click here to read that post).

Today we are going to talk about Lrrk2 flies.

What is Lrrk2?

This is Sergey Brin.


He’s a dude.

One of the founders of the search engine company “Google”. Having changed the world, he is now turning his attention to other projects.

One of those other projects is close to our hearts: Parkinson’s disease.

In 1996, Sergey’s mother started experiencing numbness in her hands. Initially it was believed to be RSI (Repetitive strain injury). But then her left leg started to drag. In 1999, following a series of tests, Sergey’s mother was diagnosed with Parkinson’s disease. It was not the first time the family had been affected by the condition: Sergey’s late aunt had also had Parkinson’s disease.

Both Sergey and his mother have had their DNA scanned for mutations that increase the risk of Parkinson’s disease. And they discovered that they were both carrying a mutation on the 12th chromosome, in a gene called PARK8 – one of the Parkinson’s disease associated genes. Autosomal dominant mutations (meaning if you have just one copy of the mutated gene) in the PARK8 gene dramatically increase one’s risk of developing Parkinson’s disease.

PARK8 provides the instructions for making an enzyme called Leucine-rich repeat kinase 2 (or Lrrk2).


The structure of Lrrk2. Source: Wikipedia

Also known as ‘Dardarin (from the Basque word “dardara” which means trembling), Lrrk2 has many functions within a cell – from helping to move things around inside the cell to helping to keep the power on (involved with mitochondrial function).


Source: Researchgate

NOTE: Curiously, mutations in the PARK8 gene are also associated with Crohn’s disease (Click here and here for more on this) – though the mutation is in a different location for PD.

Now, not everyone with this particular mutation will go on to develop Parkinson’s disease, and Sergey has decided that his chances are 50:50. But he does not appear to be taking any chances though. Being one of the founders of a large company like Google, has left Sergey with considerable resources at his disposal. And he has chosen to focus some of those resources on Lrrk2 research (call it an insurance  policy). He has done this via considerable donations to groups like the Michael J Fox foundation.


Actor Michael J Fox was diagnosed at age 30. Source: MJFox foundation

So just as Pink flies derive their name from mutations in the Parkinson’s associated Pink1 gene, Lrrk2 flies have mutations in the Lrrk2 gene.

So what have the researchers at Sheffield done with the Lrrk2 flies?

In 2013, the Sheffield researchers published an interesting research report:


Title: Ursocholanic acid rescues mitochondrial function in common forms of familial Parkinson’s disease
Authors: Mortiboys H, Aasly J, Bandmann O.
Journal: Brain. 2013 Oct;136(Pt 10):3038-50.
PMID: 24000005

In this study, the investigators took 2000 drugs (including 1040 licensed drugs and 580 naturally occurring compounds) and conducted a massive screen to identify drugs that could rescue mitochondrial dysfunction in PARK2 (Pink1) mutant cells.

Mitochondria are the power house of each cell. They keep the lights on. Without them, the lights go out and the cell dies.


Mitochondria and their location in the cell. Source: NCBI

In certain genetic forms of Parkinson’s disease (such as those associated with mutations in the PARK2 gene), the mitochondria in cells becomes dysfunctional and may not be disposed of properly (Click here to read our previous post related to this).

In their huge screen of 2000 drugs, the researchers in Sheffield identified 15 drugs that could rescue the mitochondria dysfunction in the PARK2 skins cells. Of those 15 compounds, two were chosen for further functional studies. They were:

  • Ursocholanic acid
  • Dehydro(11,12)ursolic acid lactone

Neither ursocholanic acid nor dehydro(11,12)ursolic acid lactone are FDA-licensed drugs. We have little if any information regarding their use in humans. Given this situation, the researchers turned their attention to the chemically related bile acid ‘ursodeoxycholic acid’, which has been in clinical use for more than 30 years.

What is Ursodeoxycholic Acid?

Ursodeoxycholic Acid (or UDCA) is a drug that is used to to improve bile flow and reduce gallstone formation. In the USA it is also known as ‘ursodiol’.


Ursodiol. Source: Wikimedia

Bile is a fluid that is made and released by your liver, and it stored in the gallbladder. Its function is to help us with digestion. UDCA occurs naturally in bile – it is basically a bile acid and can therefore be useful in dissolving gallstones. UDCA has been licensed for the treatment of patients since 1980. UDCA also reduces cholesterol absorption.

So what did the Sheffield researchers find with UDCA?

The researchers tested UDCA on mitochondrial function in PARK2 skin cells, and they found that the drug rescued the cells. They then tested UDCA on skin cells from people with Parkinson’s disease who had mutations in the PARK8 (Lrrk2) gene (G2019S).

The researchers had previously found impaired mitochondrial function and morphology in skin cells taken from people with PARK8 associated Parkinson’s disease (Click here to read more about this), and other groups had reported similar findings (Click here for more on this).

And when they treated the Lrrk2 cells with UDCA, guess what happened?

UDCA was able to rescue the mitochondrial effect in those cells as well!

Obviously these results excited the Sheffield scientists and they set up a collaboration with researchers at York University and from Norway, to look at the potential of UDCA in rescuing the fate of Lrrk2 flies. The results of that study were published two years ago:


Title: UDCA exerts beneficial effect on mitochondrial dysfunction in Lrrk2 (G2019S) carriers and in vivo.
Authors: Mortiboys H, Furmston R, Bronstad G, Aasly J, Elliott C, Bandmann O.
Journal: Neurology. 2015 Sep 8;85(10):846-52.
PMID: 26253449        (This article is OPEN ACCESS if you would like to read it).

The researchers tested UDCA on flies (or drosophila) with specific Lrrk2 mutations (G2019S) display a progressive loss of photoreceptor cell function in their eyes. The mitochondria in the photoreceptor are swollen and disorganised. When the investigators treated the flies with UDCA, they found approximately 70% rescue of the photoreceptor cells function.

The researchers in Sheffield concluded that UDCA has a marked rescue effect on cells from a Parkinson’s disease-associated gene mutation model, and they proposed that “mitochondrial rescue agents may be a promising novel strategy for disease-modifying therapy in Lrrk2-related PD, either given alone or in combination with Lrrk2 kinase inhibitors” (for more information about the Lrrk2 inhibitors they refer, click here).

And the good news regarding this line of research: other research groups have also observed similar beneficial effects with UDCA in models of Parkinson’s disease:


Title: Ursodeoxycholic acid suppresses mitochondria-dependent programmed cell death induced by sodium nitroprusside in SH-SY5Y cells.
Authors: Chun HS, Low WC.
Journal: Toxicology. 2012 Feb 26;292(2-3):105-12.
PMID: 22178905

This research group also demonstrated that UDCA could reduce cell death in a cellular model of Parkinson’s disease.

And this study was followed by another one from a different research group, which involved testing UDCA in animals:


Title: Ursodeoxycholic Acid Ameliorates Apoptotic Cascade in the Rotenone Model of Parkinson’s Disease: Modulation of Mitochondrial Perturbations.
Authors: Abdelkader NF, Safar MM, Salem HA.
Title: Mol Neurobiol. 2016 Mar;53(2):810-7.
PMID: 25502462

These researchers found UDCA rescued a rodent model of Parkinson’s disease (involving the neurotoxin rotenone). UDCA not only improved mitochondrial performance in the rats, but also demonstrated anti-inflammatory and anti-cell death properties.

Given all this research, the Sheffield researchers are now keen to test UDCA in clinical trials for Parkinson’s disease.

Has anyone tested UDCA in the clinic for Parkinson’s disease?

Not that we are aware of, but two groups are interested in attempting it.


Firstly, the University of Minnesota – Clinical and Translational Science Institute has registered a trial (Click here to read more about this). This trial will not, however, be testing efficacy of the drug on Parkinson’s symptoms. It will focus on measuring UDCA levels in individuals after four weeks of repeated high doses of oral UDCA (50mg/kg/day), and determining the bioenergetic profile and ATPase activity in those participants. Basically, they want to see if UDCA is safe and active in people with Parkinson’s disease.

The CurePD trust (in the UK) is also currently seeking to run a clinical trial for UDCA (Click here for more on this). The group are currently organising the funding for that trial.


EDITOR’S NOTE HERE: Before we move on, the team at the SoPD would like to say that while UDCA is a clinically available drug, it is still experimental for Parkinson’s disease. There is no indication yet that it has beneficial effects in people with Parkinson’s disease. In addition, UDCA is also is known to have side effects, which include flu symptoms, nausea, diarrhea, and back pain. And individuals have been known to have allergic reactions to UDCA treatment (Click here and here for more on the side effects of UDCA). Thus we must impress caution on anyone planning to experiment with this drug. Before attempting any kind of change in a current treatment regime, PLEASE discuss your plans with a medically qualified physician who is familiar with your case history.

Ok, so that was the flies research, what about the fish? And the… uh, tigar?

Yes. The fish are called Zebrafish (or Danio rerio).

They are a tropical freshwater fish that is widely used in biological research.


Biology researchers love these little guys because their genome has been fully sequenced and they has well characterised and testable behaviours. In addition, their development is very rapid (3 months), and its embryos are large and transparent.

And the researchers at Sheffield are using these fish to study Parkinson’s disease.

How did they do that?


Title: TigarB causes mitochondrial dysfunction and neuronal loss in Pink1 deficiency
Authors: Flinn LJ, Keatinge M, Bretaud S, Mortiboys H, Matsui H, De Felice E, Woodroof HI, Brown L, McTighe A, Soellner R, Allen CE, Heath PR, Milo M, Muqit MM, Reichert AS, Köster RW, Ingham PW, Bandmann O.
Journal: Ann Neurol. 2013 Dec;74(6):837-47.
24027110        (This article is OPEN ACCESS if you would like to read it)

Firstly, the group at Sheffield generated zebrafish that had a mutation in the Parkinson’s associated gene ‘PARK6’. This gene provides the plans for the production of a protein called Pink1 (we have previously discussed Pink1 – click here to read more on this).

In normal healthy cells, the Pink1 protein is absorbed by mitochondria and eventually degraded as it is not used. In unhealthy cells, however, this process becomes inhibited and Pink1 starts to accumulate on the outer surface of the mitochondria. Sitting on the surface, it starts grabbing another Parkinson’s associated protein called Parkin. This pairing is a signal to the cell that this particular mitochondria is not healthy and needs to be removed.


Pink1 and Parkin in normal (right) and unhealthy (left) situations. Source: Hindawi

The process by which mitochondria are removed is called mitophagy. Mitophagy is part of the autophagy process, which is an absolutely essential function in a cell. Without autophagy, old proteins and mitochondria will pile up making the cell sick and eventually it dies. Through the process of autophagy, the cell can break down the old protein, clearing the way for fresh new proteins to do their job.

Think of autophagy as the waste disposal/recycling process of the cell.


The process of autophagy. Source: Wormbook

Waste material inside a cell is collected in membranes that form sacs (called vesicles). These vesicles then bind to another sac (called a lysosome) which contains enzymes that will breakdown and degrade the waste material. The degraded waste material can then be recycled or disposed of by spitting it out of the cell.

In the case of a PARK6 mutations, Pink1 protein can not function properly with Parkin and the autophagy process breaks down. As a result, the old or unhealthy mitochondria start to pile up in the cell, resulting in the cell getting sick and dying.

Now back to the Zebrafish.

When the Sheffield researchers mutated PARK6 in the zebrafish, they noticed that the fish had a very early and persistent loss of dopamine neurons in their brains. These fish also had enlarged, unhealthy mitochondria and reduced mitochondrial activity.

Given this result, the investigators next wanted to identify which genes have increased or decreased levels of activity as a result of this genetic manipulation. They identified 108 genes that were higher in the PARK6 mutant, and 146 genes had lower activity.

One gene in particular had activity levels 12 times higher in the PARK6 mutant fish than the normal zebrafish.

The name of that gene? TP53-Induced Glycolysis And Apoptosis Regulator (or Tigar).

What is Tigar?

Tigar is a gene that provides the instructions for making a protein that is activated by p53 (also known as TP53).

What does that mean?

p53 is a protein that has three major functions: controlling cell division, DNA repair, and apoptosis (or cell death). p53 performs these functions as a transcriptional activator (that is a protein that binds to DNA and helps produce RNA (the process of transcription) – see our previous post explaining this).


p53 protein structure, bound to DNA (in gold). Source: Wikipedia

In regulating the cell division, p53 prevents cells from dividing too much and in this role it is known as a tumour suppression – it suppresses the emergence of cancerous tumours. Genetic mutations in the p53 gene result in run away cell division, and (surprise!) as many as 50% of all human tumours contain mutations in the p53 gene.


Cancer vs no cancer. Source: Khan Academy

In DNA repair, p53 is sometimes called “the guardian of the genome” as it prevents mutations and helps to conserve stability in the genome. This function also serves to prevent the development of cancer, by helping to repair potentially cancer causing mutations….and in this role it is known as a tumour suppression. Obviously, if there is a mutation in the p53 gene, less DNA repair will occur – increasing the risk of cancer occurring.

And finally, in cell death, p53 plays a critical role in telling a cell when to die. And (continuing with the cancer theme), if there is a mutation in the p53 gene, fewer cells will be told to die – increasing the risk of cancer occurring. And in this role p53 is known as a tumour suppression.

In normal cells, the levels of p53 protein are usually low. When a cell suffers DNA damage and stress, there is often an increase in the amount of p53 protein. If this increases past a particular threshold, then the cell will be instructed to die.

If you haven’t guessed yet, p53 is a major player inside most cell, and it controls the activity of a lot of genes.

And one of those genes is Tigar.

But what does Tigar actually do?

So we have explained the “TP53-Induced” part of the “TP53-Induced Glycolysis And Apoptosis Regulator” name, let’s now focus on the “Glycolysis And Apoptosis Regulator”

Tigar is an interesting protein because it is an enzyme that primarily functions as a regulator of the breaking down of glucose (“Glycolysis” involves the conversion of glucose into a chemical called pyruvate). In addition to this role, however, Tigar acts in preventing cell death (or apoptosis).

Increased levels of Tigar protects cells from oxidative-stress induced apoptosis, by decreasing the levels of free radicals. In this way, it promotes anti-oxidant activities.

But hang on a second, anti-oxidant activity should be good for the cell right? Why are the dopamine cells are dying if Tigar levels are increasing in the PARK6 mutants?

Fantastic question!

The answer: TIGAR is also a negative regulator of a process called mitophagy. As we discussed above, mitophagy is the process of removing mitochondria by autophagy. Increases in the levels of TIGAR blocks mitophagy in a cell, and results in an increased number of swollen and unhealthy mitochondria in those cells (Click here to read more about this). These swollen mitochondria are comparable to the enlarged mitochondria identified the PARK6 zebrafish by the Sheffield researchers.

And the researchers believe that this may be the cause of the cell death in the PARK6 zebrafish – the double impact of PARK6 and Tigar induced problems with mitophagy.

NOTE: Problems with mitophagy is believed to be an important mechanism in the development of early-onset Parkinson’s disease (Click here for a recent review on this)

Ok, and what did the Sheffield researchers do next?

Given that there was such a huge increase in Tigar levels in the PARK6 zebrafish, the investigators decided to reduce Tigar levels in the PARK6 zebrafish to see what impact this would have on the fish (and their mitochondria).

Remarkably, reductions of Tigar levels resulted in complete rescue of the dopamine neurons in the PARK6 fish. It also increased mitochondrial activity in those cells, and reduced the activation of the microglia cells, which can also play a role in the removal of sick cells in the brain.

The researchers concluded that the results demonstrate that TIGAR is “a promising novel target for disease‐modifying therapy in Pink1‐related Parkinson’s disease”.

And what are the researchers planning to do next with Tigar?

Prof Oliver Bandmann, the senior scientist who ran the study, has said that they “need to finish studying TIGAR levels in the brains of people with Parkinson’s and want to better understand how this protein is involved in maintaining the cell batteries – called ‘mitochondria'” (Source).

Our guess is that the group will also be conducting studies looking at Tigar reduction in rodent models of Parkinson’s disease to determine if this is a viable target in mammals. If Tigar reduction in rodents is found to be effective, the researchers will probably turn their attention to drug screening studies to identify currently available drugs that can reduce the activity of Tigar. Such a drug would provide us with yet another potential treatment for Parkinson’s disease.

We’ll be keeping an eye out for these pieces of research.

This is all very interesting. What does the future hold for Parkinson’s research in Sheffield?

Well, in a word: Keapstone.


In March, the University of Sheffield and Parkinson’s UK have launched a new £1 million virtual biotech company called “Keapstone Therapeutics” (see the press release by clicking here).


Source: Parkinson’s UK

The goal of the company – the first of its kind – is to combine world-leading research from the University with funding and expertise from the charity to help develop revolutionary drugs for Parkinson’s disease.

What is virtual about it? The biotech won’t be building its own labs, employing a team of specialist laboratory scientists, or buying any high-tech equipment (which would all be incredibly expensive). Rather they will form partnerships with groups that do specific tasks the best.

Here is a video of Dr Author Roach (director of Research at Parkinson’s UK) explaining the idea behind this endeavour:

By seeking a collaboration with Sheffield in the creation of a spin-out biotech company, Parkinson’s UK is not only acknowledging Sheffield’s track record, but also making an investment in their future research. While we cannot be entirely sure of what the long-term future holds for Parkinson’s research in Sheffield, we do know that Keapstone will be an important aspect of it in the immediate future.

Could this be a model for the future of Parkinson’s disease research? Only time will tell. We will have a closer look at Keapstone Therapeutics in an upcoming post.

Click here to learn more about the virtual biotech project.

So what does it all mean?

In 2017, we here at the SoPD have decided to begin highlighting some of the Parkinson’s disease research centres as an addition feature on the blog. We have not been approached by the research group in Sheffield or the University itself, and our selection of this city as our first case study was based purely on the fact that we really like what is happening there with regards to Parkinson’s research!

The research group in Sheffield has undertaken multiple lines of research which could potentially providing us with several novel treatment options for Parkinson’s disease. These lines of research have focused not only on clinically available drugs, but also identifying novel targets. We like what they are doing and will keep a close eye on progress there.

And over the next year we will select additional centres of Parkinson’s research based on the same criteria (us liking what they are doing). Our next case study will be the Van Andel Research Institute in Grand Rapids, Michigan (we would hate to be accused of having a UK bias).

EDITORIAL NOTE:  Under absolutely no circumstances should anyone reading the material on this website consider it medical advice. The information provided here is for educational purposes only. Before considering or attempting any change in your treatment regime, PLEASE consult with your doctor or neurologist. While some of the drugs discussed on this website are clinically available, they may have serious side effects. We urge caution and professional consultation before altering any treatment regime. SoPD can not be held responsible for any actions taken based on the information provided here. 

The banner for today’s post was sourced from TotalProduceLocal