Tagged: free radicals

A virtual reality for Parkinson’s: Keapstone

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In 2017, Parkinson’s UK – the largest charitable funder of Parkinson’s disease research in Europe – took a bold step forward in their efforts to find novel therapies.

In addition to funding a wide range of small and large academic research projects and supporting clinical trials, they have also decided to set up ‘virtual biotech’ companies – providing focused efforts to develop new drugs for Parkinson’s, targeting very specific therapeutic areas.

In today’s post we will look at the science behind their first virtual biotech company: Keapstone.


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A virtual world of bioscience. Source: Cast-Pharma

I have previously discussed the fantastic Parkinson’s-related research being conducted at Sheffield University (Click here to read that post). Particularly at the Sheffield Institute for Translational Neuroscience (SITraN) which was 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 other neurodegenerative disorders such as Parkinson’s and Alzheimer’s disease.

The research being conducted at the SITraN has given rise to multiple lines of research following up interesting drug candidates which are gradually being taken to the clinic for various conditions, including Parkinson’s.

It’s all very impressive.

And apparently I’m not the only one who thought it was impressive.

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Hey DJ, I-so-sit-rate!

The title of this post probably reads like the mad, drug-fuelled scream of a drunk Saturday night party animal, but the elements of it may be VERY important for a particular kind of Parkinson’s disease.

Mutations in a gene called DJ-1 can cause an early onset form of Parkinson’s disease. The protein of DJ-1 plays an important role in how cells handle oxidative stress – or the increase in damaging free radicals (explained below).

This week researchers announced that they have found an interesting new therapeutic target for people with DJ-1 associated Parkinson’s disease: A chemical called Isocitrate.

In this post, we will discuss what DJ-1 is involved with Parkinson’s disease, how isocitrate helps the situation, and what the results of new research mean for future therapeutic strategies.


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Source: Listchallenge

In 2017, we are not only observing the 200 year anniversary of the first description of Parkinson’s disease (by one Mr James Parkinson), but also the 20th anniversary of the discovery of the first genetic variation associated with the condition (Click here to read more about that). Our understanding of the genetics of Parkinson’s disease since 1997, has revolutionised the way we look at Parkinson’s disease and opened new doors that have aided us in our understanding.

During the last 20 years, we have identified numerous sections of DNA (these regions are called genes) where small errors in the genetic coding (mutations or variants) can result in an increased risk of developing Parkinson’s disease. As the graph below indicates, mutations in some of these genes are very rare, but infer a very high risk, while others are quite common but have a low risk of Parkinson’s disease.

The genetics of PD. Source: Journal of Parkinson’s disease

Some of the genetic mutation need to be provided by both the parents for Parkinson’s to develop (an ‘autosomal recessive‘ mutation – the yellow circles in the graph above); while in other cases the genetic variant needs only to be provided by one of the parents (an ‘autosomal dominant’ mutation – the blue circles). Many of the genetic mutations are very common and simply considered a region of increased risk (green circles).

Importantly, all of these genes provide the instructions for making a protein – which are the functional parts in a cell. And each of these proteins have specific roles in biological processes. These functions tell us a little bit about how Parkinson’s disease may be working. Each of them is a piece of the jigsaw puzzle that we are trying to finish. As you can see in the image below, many of the genes mentioned in the graph above give rise to proteins that are involved in different parts of the process of autophagy – or the waste disposal system of the cell. You may notice that some proteins, like SCNA (otherwise known as alpha synuclein), are involved in multiple steps in this process.

The process of autophagy. Source: Nature

In today’s post we are going to look at new research regarding just one of these genes/proteins. It is called DJ-1, also known as Parkinson disease protein 7 (or PARK7).

What is DJ-1?

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Glutathione – Getting the k’NAC’k of Parkinson’s disease

NAC

The image above presents a ‘before treatment’ (left) and ‘after treatment’ (right) brain scan image from a recent research report of a clinical study that looked at the use of Acetylcysteine (also known as N-acetylcysteine or simply NAC) in Parkinson’s disease.

DaTscan brain imaging technique allows us to look at the level of dopamine processing in an individual’s brain. Red areas representing a lot; blue areas – not so much. The image above represents a rather remarkable result and it certainly grabbed our attention here at the SoPD HQ (I have never seen anything like it!).

In today’s post, we will review the science behind this NAC and discuss what is happening with ongoing clinical trials.


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Source: The Register

Let me ask you a personal question:

Have you ever overdosed on Paracetamol?

Regardless of your answer to that question, one of the main treatments for Paracetamol overdose is administration of a drug called ‘Acetylcysteine’.

Why are you telling me this?

Because acetylcysteine is currently being assessed as a potential treatment for Parkinson’s disease.

Oh I see. Tell me more. What is acetylcysteine?

Acetylcysteine-2D-skeletalAcetylcysteine. Source: Wikimedia

Acetylcysteine (N-acetylcysteine or NAC – commercially named Mucomyst) is a prodrug – that is a compound that undergoes a transformation when ingested by the body and then begins exhibiting pharmacological effects. Acetylcysteine serves as a prodrug to a protein called L-cysteine, and – just as L-dopa is an intermediate in the production of dopamine – L-cysteine is an intermediate in the production of another protein called glutathione.

Take home message: Acetylcysteine allows for increased production of Glutathione.

What is glutathione?

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Glutathione. Source: Wikipedia

Glutathione (pronounced “gloota-thigh-own”) is a tripeptide (a string of three amino acids connected by peptide bonds) containing the amino acids glycine, glutamic acid, and cysteine. It is produced naturally in nearly all cells. In the brain, glutathione is concentrated in the helper cells (called astrocytes) and also in the branches of neurons, but not in the actual cell body of the neuron.

It functions as a potent antioxidant.

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Iron, life force, and Parkinson’s disease

pranaLogo

‘Prana’ is a Hindu Sanskrit word meaning “life force”.

An Australian biotech company has chosen this word for their name.

Recently Prana Biotechnology Ltd announced some exciting results from their Parkinson’s disease research programme.

In today’s post we will look at what the company is doing, the science underlying the business plan, and review the results they have so far.


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Source: ADPD2017

At the end of March, over 3000 researchers in the field of neurodegeneration gathered in the Austrian capital of Vienna for the 13th International Conference on Alzheimer’s and Parkinson’s Diseases and Related Neurological Disorders (also known as ADPD2017).

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The Vienna city hall. Source: EUtourists

A lot of interesting new research in the field of Parkinson’s disease was presented at the conference (we will look at some other presentation in future posts), but one was of particular interest to us here at SoPD HQ.

The poster entitled: Abstract: 104 – PBT434 prevents neuronal loss, motor function and cognitive impairment in preclinical models of movement disorders by modulation of intracellular iron’, was presented by Associate Professor David Finkelstein, of the Florey Institute of Neuroscience and Mental Health (Melbourne, Australia).

Unfortunately the ADPD2017 conference’s scientific programme search engine does not allow for individual abstracts to be linked to on the web so if you would like to read the abstract, you will need to click here for the search engine page and search for ‘PBT434’ or ‘Finkelstein’ in the appropriate boxes.

Prof Finkelstein was presenting preclinical research that had been conducted by an Australian biotech company called Prana Biotechnology Ltd.

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Source: Prana Biotechnology Ltd

What does the company do?

Prana Biotechnology Ltd has a large portfolio of over 1000 small chemical agents that they have termed ‘MPACs’ (or Metal Protein Attenuating Compounds). These compounds are designed to interrupt the interactions between particular metals and target proteins in the brain. The goal of this interruption is to prevent deterioration of brain cells in neurodegenerative conditions.

For Parkinson’s disease, the company is proposing a particular iron chelator they have called PBT434.

What is an iron chelator?

Iron chelator therapy involves the removal of excess iron from the body with special drugs. Chelate is from the Greek word ‘chela’ meaning “claw”.

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Chelator therapy. Source: Stanford

Iron overload in the body is a common medical problem, sometimes arising from disorders of increased iron absorption such as hereditary haemochromatosis. Iron chelator therapy represents one method of reducing the levels of iron in the body.

But why is iron overload a problem?

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Iron. Source: GlobalSpec

Good question. It involves the basic properties of iron.

Iron is a chemical element (symbol Fe). It has the atomic number 26 and by mass it is the most common element on Earth (it makes up much of Earth’s outer and inner core). It is absolutely essential for cellular life on this planet as it is involved with the interactions between proteins and enzymes, critical in the transport of oxygen, and required for the regulation of cell growth and differentiation.

So why then – as Rosalind asked in Shakespeare’s As You Like It – “can one desire too much of a good thing?”

Well, if you think back to high school chemistry class you may recall that there are these things called electrons. And if you have a really good memory, you will recall that the chemical hydrogen has one electron, while iron has 26 (hence the atomic number 26).

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The electrons of iron and hydrogen. Source: Hypertonicblog

Iron has a really interesting property: it has the ability to either donate or take electrons. And this ability to mediate electron transfer is one of the reasons why iron is so important in the body.

Iron’s ability to donate and accept electrons means that when there is a lot of iron present it can inadvertently cause the production of free radicals. We have previously discussed free radicals (Click here for that post), but basically a free radical is an unstable molecule – unstable because they are missing electrons.

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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.

Antioxidants can help try and restore the balance, but in the case of iron overload iron doctors will prescribe chelator treatment to deal with the situation more efficiently. By soaking up excess iron, we can limit the amount of damage caused by the surplus of iron.

So what research has been done regarding iron content and the Parkinsonian brain?

Actually, quite a lot.

In 1968, Dr Kenneth Earle used an X-ray based technique to examine the amount of iron in the substantia nigra of people with Parkinson’s disease (Source). The substantial nigra is one of the regions in the brain most badly damaged by the condition – it is where most of the brain’s dopamine neurones resided.

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The dark pigmented dopamine neurons in the substantia nigra are reduced in the Parkinson’s disease brain (right). Source:Memorangapp

Earle examined 11 samples and compared them to unknown number of control samples and his results were a little startling:

The concentration of iron in Parkinsonian samples was two times higher than that of the control samples.

Since that first study, approximately 30 investigations have been made into levels of iron in the Parkinsonian brain. Eleven of those studies have replicated the Earle study by looking at postmortem tissue. They have used different techniques and the results have varied somewhat:

  • Sofic et al. (1988)                             1.8x increase in iron levels
  • Dexter et al. (1989)                         1.3x increase in iron levels
  • Uitti et al. (1989)                              1.1x increase in iron levels
  • Riederer et al 1989                         1.3x increase in iron levels
  • Griffiths and Crossman (1993)     2.0x increase in iron levels
  • Mann et al. (1994)                           1.6x increase in iron levels
  • Loeffler et al. (1995)                       0.9   (lower)
  • Galazka-Friedman et al., 1996     1.0   (no difference)
  • Wypijewska et al. (2010)               1.0   (no difference)
  • Visanji et al, 2013                            1.7x increase in iron levels

Overall, however, there does appear to be a trend in the direction of higher levels of iron in the Parkinsonian brains. A recent meta-analysis of all this data confirmed this assessment as well as noting an increase in the caudate putamen (the region of the brain where the dopamine neuron branches release their dopamine – Click here for that study).

Brain imaging of iron (using transcranial sonography and magnetic resonance imaging (MRI)) has also demonstrated a strong correlation between iron levels in the substantia nigra region and Parkinson’s disease severity/duration (Click here and here to read more on this).

Thus, there appears to be an increase of iron in the regions most affected by Parkinson’s disease and this finding has lead researchers to ask whether reducing this increase in iron may help in the treatment of Parkinson’s disease.

How could iron overload be bad in Parkinson’s disease?

Well in addition to causing the production of free radicals, there are many possible ways in which iron accumulation could be aggravating cell loss in Parkinson’s disease.

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Possible causes and consequences of iron overload in Parkinson’s disease. Source: Hindawi

High levels of iron can cause the oxidation of dopamine, which results in the production of hydrogen peroxide (H2O– a reactive oxygen species – the stuff that is used to bleach hair and is also used as a propellant in rocketry!). This reaction can cause further oxidative stress that can then lead to a range of consequences including protein misfolding, lipid peroxidation (which can cause the accumulation of the Parkinson’s associated protein alpha synuclein), mitochondrial dysfunction, and activation of immune cells in the brain.

And this is just a taster of the consequences.

For further reading on this topic we recommend two very good reviews – click here and here.

Ok, so iron overload is bad, but what was the research presented in Austria?

The abstract:

Title: PBT434 prevents neuronal loss, motor function and cognitive impairment in preclinical models of movement disorders by modulation of intracellular iron
Authors: D. Finkelstein, P. Adlard, E. Gautier, J. Parsons, P. Huggins, K. Barnham, R. Cherny
Location: C01.a Posters – Theme C – Alpha-Synucleinopathies

The researchers at Prana Biotechnology Ltd assessed the potential of one of their candidate drugs, PBT434, in both cell culture and animal models of Parkinson’s disease. The PBT434 drug was selected for further investigation based on its performance in cell culture assays designed to test the inhibition of oxidative stress and iron-mediated aggregation of Parkinson’s associated proteins like alpha synuclein.

PBT434 significantly reduced the accumulation of alpha synuclein and markers of oxidative stress, and prevented neuronal loss.

The investigators also demonstrated that orally administered PBT434 readily crossed the blood brain barrier and entered the brain. In addition the drug was well-tolerated in the experimental animals and improved motor function in toxin-induced (MPTP and 6-hydroxydopamine) and transgenic mouse models of Parkinson’s disease (alpha synuclein -A53T and tau – rTg4510).

These results are in agreement with previous studies that have looked at iron chelator therapy in models of Parkinson’s disease (Click here, here and here for some examples)

Interestingly, PBT434 also demonstrated neuroprotective properties in animal models of multiple systems atrophy (or MSA). Suggesting that perhaps iron chelation could be a broad neuroprotective approach.

The researchers concluded that this preclinical data demonstrates the efficacy of PBT434 as a clinical candidate for Parkinson’s disease. PBT434 shows a strong toxicology profile and favourable therapeutic activity.  Prana is preparing its pre-clinical development package for PBT434 to initiate human clinical trials.

Does Prana have any other drugs in clinical trials?

Yes, they do.

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Source: Prana

Prana Biotechnology has another product called PBT2.

The company currently has two clinical trial programs for PBT2 focused on two other neurodegenerative diseases: Alzheimer’s disease and Huntington’s disease.

The Alzheimer’s study was called the IMAGINE Trial, but (there is always a ‘but’) recently PBT2 failed to meet its primary endpoint (significantly reducing levels of beta-amyloid  – the perceived bad guy in Alzheimer’s disease) in a phase III trial of mild Alzheimer’s disease. PBT2 was, however, shown to be safe and very well tolerated over the 52 week trial, with no difference in the occurrence of adverse events between the placebo and treated groups.

In addition, there was less atrophy (shrinkage) in the brains of those patients treated with PBT2 when compared to control brains, 2.6% and 4.0%, respectively (based on brain imaging).  The company is tracking measures of brain volume and cognition in a 12 month extension study. It could be interesting to continue that follow up long term to evaluate the consequences of long term use of this drug on Alzheimer’s disease – even if the effect is minimal, any drug that can slow the disease down is useful and could be used in conjunction with other neuroprotective medications.

For Huntington’s disease, the company is also using the PBT2 drug and this study has had a bit more success. The study, called Reach2HD, was a six month phase II clinical trial in 109 patients with early to mid-stage Huntington’s disease, across 20 sites in the US and Australia. The company was aiming to assess the safety profile of this drug in this particular condition, as well as determining the motor and behavioural benefits.

In the ReachHD study, PBT2 showed signs of improving some aspects of cognitive function in the study, which potentially represents a major event for a disease for which there is very little in the way of medical treatments.

For a full description of the PBT2 trials, see this wikipedia page on the topic.

Is Prana the only research group working on iron chelators technology for Parkinson’s disease?

No.

There is a large EU-based consortium called FAIR PARK II, which is running a five year trial (2015 – 2020) of the iron chelator deferiprone (also known as Ferriprox). The study is a multi-centre, placebo-controlled, randomised clinical trial involving 338 people with recently diagnosed Parkinson’s disease.

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The population will be divided into two group (169 subjects each). They will then be assigned either deferiprone (15 mg/kg twice a day) or a placebo. Each subject will be given 9-months of treatment followed by a 1-month post-treatment monitoring period, in order to assess the disease-modifying effect of deferiprone (versus placebo).

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Deferiprone. Source: SGPharma

As far as we are aware, this FAIR PARK II clinical trial is still recruiting participants – please click here to read more about this – thus it will most likely be some time before we hear the results of this study.

Are there natural sources of chelators?

Yes there are. In fact, many natural antioxidants exert some chelating activities.

Prominent among the natural sources of chelators: Green tea has components of plant extracts, such as epigallocatechin gallate (EGCG – which we have previously discussed in regards to Parkinson’s disease, click here to read that post) which possess structures which infer metal chelating properties.

As we have said before people, drink more green tea!

cup and teapot of linden tea and flowers isolated on white

Anyone fancy a cuppa? Source: Expertrain

So what does it all mean?

Summing up: We do not know what causes Parkinson’s disease. Most of our experimental treatments are focused on the biological events that occur in the brain around and after the time of diagnosis. These include an apparent accumulation of iron in affected brain regions.

Research groups are currently experimenting with drugs that reduce the levels of iron in the brain as a potential treatment for Parkinson’s disease. Preclinical data certainly look positive. We will now have to wait and see if those results translate into the human.

Previous clinical trials of metal chelators in neurodegeneration have had mixed success in demonstrating positive benefits. It may well be, however, that this treatment approach should be used in conjunction with other neuroprotective approaches – as a supplement. It will be interesting to see how Prana Biotechnology’s drug PBT434 fares in human clinical trials for Parkinson’s disease.

Stay tuned for more on this.


UPDATE – 3rd May 2017

Today the results of a double-blind, phase II clinical trial of iron chelator deferiprone in Parkinson’s disease were published. The results of the study indicate a mildly positive effect (though not statistically significant) after 6 months of daily treatment.

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Title: Brain iron chelation by deferiprone in a phase 2 randomised double-blinded placebo controlled clinical trial in Parkinson’s disease
Authors: Martin-Bastida A, Ward RJ, Newbould R, Piccini P, Sharp D, Kabba C, Patel MC, Spino M, Connelly J, Tricta F, Crichton RR & Dexter DT
Journal: Scientific Reports (2017), 7, 1398.
PMID: 28469157        (This article is OPEN ACCESS if you would like to read it)

In this Phase 2 randomised, double-blinded, placebo controlled clinical trial, the researchers recruited 22 people with early stage Parkinson’s disease (disease duration of less than 5 years; 12 males and 10 females; aged 50–75 years). They were randomly assigned to either a placebo group (8 participants), or one of two deferiprone treated groups: 20mg/kg per day (7 participants) or 30mg/kg per day (7 participants). The treatment was two daily oral doses (taken morning and evening), and administered for 6 months with neurological examinations, brain imaging and blood sample collections being conducted at 0, 3 and 6 months.

Deferiprone therapy was well tolerated and brain imaging indicated clearance of iron from various parts of the brain in the treatment group compared to the placebo group. Interestingly, the 30mg/kg deferiprone treated group demonstrated a trend for improvement in motor-UPDRS scores and quality of life (although this was not statistically significance). The researchers concluded that “more extensive clinical trials into the potential benefits of iron chelation in PD”.

Given the size of the groups (7 people) and the length of the treatment period (only 6 months) in this study it is not really a surprise that the researchers did not see a major effect. That said, it is very intriguing that they did see a trend towards motor score benefits in the  30mg/kg deferiprone group – remembering that this is a double blind study (so even the investigators were blind as to which group the subjects were in).

We will now wait to see what the FAIR PARK II clinical trial finds.


UPDATE: 28th June 2017

Today, the research that Prana biotechnology Ltd was presenting in Vienna earlier this year was published:

Prana

Title: The novel compound PBT434 prevents iron mediated neurodegeneration and alpha-synuclein toxicity in multiple models of Parkinson’s disease.
Authors: Finkelstein DI, Billings JL, Adlard PA, Ayton S, Sedjahtera A, Masters CL, Wilkins S, Shackleford DM, Charman SA, Bal W, Zawisza IA, Kurowska E, Gundlach AL, Ma S, Bush AI, Hare DJ, Doble PA, Crawford S, Gautier EC, Parsons J, Huggins P, Barnham KJ, Cherny RA.
Journal: Acta Neuropathol Commun. 2017 Jun 28;5(1):53.
PMID: 28659169             (This article is OPEN ACCESS if you would like to read it)

The results suggest that PBT434 is far less potent than deferiprone or deferoxamine at lowering cellular iron levels, but this weakness is compensated by the reduced levels of alpha synuclein accumulation in models of Parkinson’s disease. PBT434 certainly appears to be neuroprotective demonstrating improvements in motor function, neuropathology and biochemical markers of disease state in three different animal models of Parkinson’s disease.

The researchers provide little information as to when the company will be exploring clinical trials for this drug, but in the press release associated with the publication, Dr David Stamler (Prana’s Chief Medical Officer and Senior Vice President, Clinical Development) was quoted saying that they “are eager to begin clinical testing of PBT434”. We’ll keep an eye to the ground for any further news.


FULL DISCLOSURE: Prana Biotechnology Ltd is an Australasian biotechnology company that is publicly listed on the ASX. The information presented here is for educational purposes. Under no circumstances should investment decisions be made based on the information provided here. The SoPD website has no financial or beneficial connection to either company. We have not been approached/contacted by the company to produce this post, nor have we alerted them to its production. We are simply presenting this information here as we thought the science of what the company is doing might be of interest to other readers. 

In addition, under absolutely no circumstances should anyone reading this material consider it medical advice. The material provided here is for educational purposes only. Before considering or attempting any change in your treatment regime, PLEASE consult with your doctor or neurologist. Metal chelators are clinically available medications, but it is not without side effects (for more on this, see this website). We urge caution and professional consultation before altering a 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 Prana

NRF2 and Parkinson’s disease

nrf2-effects-on-cells

Over the Christmas festive period an interesting study was published in the journal Proceedings of the National Academy of Sciences (PNAS). It was about a protein called Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2) that has some impressive properties that could be good for Parkinson’s disease.

In today’s post we will review the results of the study and discuss what they mean for Parkinson’s disease.


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We are going to be talking about free radicals. Source: PRIMOH2

Antioxidants are one of those subjects that is often discussed, but not well understood. So before we review the study that was published last week, let’s first have a look at what we mean when we talk about antioxidants.

What is an antioxidant?

An antioxidant is simply a molecule that prevents the oxidation of other molecules.

OK, but what does that mean?

Well, the cells in your body are made of molecules. Molecules are combinations atoms of one or more elements joined by chemical bonds. Atoms consist of a nucleus, neutrons, protons and electrons.

Oxidation is simply 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.

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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.

What is a free radical?

A free radical is an unstable molecule – unstable because it is missing electrons. They react quickly with other molecules, trying to capture the needed electron to re-gain stability. Free radicals will literally attack the nearest stable molecule, stealing 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.

Antioxidants are thus the good guys in this situation. They are molecules that neutralize free radicals by donating one of their own electrons. The antioxidant don’t become free radicals by donating an electron because by their very nature they are stable with or without that extra electron.

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How free radicals and antioxidants work. Source: h2miraclewater

Interesting, but what does all this have to do with this new gene Nrf2?

Well, Nrf2 is a ‘transcription factor’ with some interesting properties.

What is a transcription factor?

So you remember your high school science class when some adult at the front of the class was talking about biology 101 – DNA gives rise to RNA, RNA gives rise to protein.

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The basic of biology. Source: Youtube

Ultimately this is a circular cycle, because the protein that is produced using RNA is required at all levels of this process. Some of the protein is required for making RNA from DNA, while other proteins are required for making protein from the RNA instructions.

A transcription factor is a protein that is involved in the process of converting (or transcribing) DNA into RNA.

Now, a transcription factor can be an ‘activator’ of transcription – that is initiating or helping the process of generating RNA from DNA.

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An example of a transciptional activator. Source: Khan Academy

Or it can be a repressor of transcription – blocking the machinery (required for generating RNA) from doing it’s work.

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An example of a transciptional repressor. Source: Khan Academy

Nrf2 is an activator of transcription. When it binds to DNA to aids in the production of RNA, which then results in specific proteins being produced.

And this is where Nrf2 gets interesting.

You see, Nrf2 binds to antioxidant response elements (ARE).

What are ARE?

Antioxidant response elements (ARE) are regions of DNA is commonly found in the regulatory region of genes encoding various antioxidant and cytoprotective enzymes.

The regulatory region of genes is the section of DNA where transcription is initiated for each gene. They are pieces of DNA that a transcription factor like Nrf2 binds to and activates the production of RNA.

ARE are particularly interesting because these regions reside in the regulatory regions of genes that encode naturally occurring antioxidant and protective proteins. And given that antioxidants and protective proteins are generally considered a good thing for sick/dying cells, you can see why Nrf2 is an interesting protein to investigate.

By binding to ARE, Nrf2 is directly encouraging the production of naturally occurring antioxidant and protective proteins. And this is why a lot of people are excited by Nrf2 and call it the ‘next big thing’.

So what did the new research study report?

Well, this is where the story gets really interesting.

The researchers in the new study found that Nrf2 has some additional features that may be completely unrelated to the antioxidant properties:

nrf2

Title: Nrf2 mitigates LRRK2- and α-synuclein-induced neurodegeneration by modulating proteostasis.
Authors: Skibinski G, Hwang V, Ando DM, Daub A, Lee AK, Ravisankar A, Modan S, Finucane MM, Shaby BA, Finkbeiner S.
Journal: Proc Natl Acad Sci U S A. 2016 Dec 27. pii: 201522872.
PMID: 28028237

The researchers wanted to determine what effect introducing exaggerated amounts of Nrf2 into cell culture models of Parkinson’s disease would have on the behaviour and survival of the cells. There were two types of cell culture models of Parkinson’s disease used in the study: one produced a lot of the Parkinson’s associated protein alpha synuclein (normal un-mutated) and the other cell culture model involved two mutations in the Lrrk2 gene (we have previously discussed Lrrk2 – click here to read that post).

The researchers had previously demonstrated that both of these cell culture models of Parkinson’s disease exhibited increased levels of cell death when compared with normal cells. In the current study, when the researchers artificially exaggerated the amounts of  Nrf2 in both sets of cell cultures, they found that not only did Nrf2 reduce Lrrk2 and alpha-synuclein toxicity in cell culture, but it also influenced alpha-synuclein protein regulation, by increasing the degradation of the protein. This means that Nrf2 increased the disposal of the unnecessary excess of alpha synuclein.

In addition, Nrf2 also promoted the collection of free-floating mutant Lrrk2 and bundling it up into dense ‘inclusion bodies’ – dense clusters which are similar to the Lewy bodies of Parkinson’s disease but inclusion bodies are not associated with cell death. The scientists concluded that excessive levels of Nrf2 help to make the cells healthier and that this could represent a new target for future therapies of Parkinson’s disease. The researchers acknowledge that the ARE-related features of Nrf2 may be also playing a beneficial role in the cells, but this is the first time the alpha synuclein and Lrrk2 features have been identified.

Sounds great. Are there any catches?

Yes, a very interesting one.

The response of Nrf2 is time-dependent. The researchers found that over stimulation with Nrf2 leads to natural compensation from cells that eventually limits the activity of Nrf2. In other words, too much of a good thing loses it’s affect over time. Biology is one giant balancing act and sometimes when one factor is artificially introduced, cells will compensate regardless of whether it’s a good thing or not.

The researchers suggested that this issue could potentially be over come by periodic use of Nrf2, rather than simply chronic (or continuous) use of the protein. This still needs to be determined, however, in follow up experiments.

What does it all mean?

This new study provides us with new data relating to a protein that has been seen as holding great promise in the treatment of neurodegenerative conditions (not just Parkinson’s disease). The new research, however, demonstrates some interesting characteristic of Nrf2 specific to two Parkinson’s disease related genes.

Nrf2 has been considered a drug target for some time and agents targeting this protein have been patented and are under investigation (Click here to read more on this). We will be keeping an eye out for these compounds and we’ll report here the results of any research being conducted on them.


Interesting side note here:

We have previously discussed the treatments for Parkinson’s disease that were prescribed in India over 2000 years ago (Click here for that post). Outlined in the ancient texts, called the ‘Ayurveda’ (/aɪ.ərˈveɪdə/; Sanskrit for “the science of life” or “Life-knowledge”) was the use of the seeds of Mucuna pruriens in treating conditions of tremor. The seeds of this tropical legume we now know have extremely high levels of L-dopa in them (L-dopa being the standard therapy for Parkinson’s disease in modern medicine).

Here’s the interesting bit:

A second popular Ayurvedic treatment that is popular for Parkinson’s disease is Curcumin.

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Tumeric. Source: Cerebrum

Curcumin is an active component of turmeric (Curcuma longa), a dietary spice used in Indian cuisine and medicine. Curcumin exhibits antioxidant, anti-inflammatory and anti-cancer properties, crosses the blood-brain barrier and there are numerous studies that indicate neuroprotective properties in various models of neurological disorders.

Curcumin has also been shown to activate Nrf2 (Click here , here and here for more on this).

It has also been shown to prevent the aggregation of alpha synuclein (click here for more on this).

We are always amazed at the curious little connection with ancient remedies that can be found in modern research and medical practice, and we thought we’d share this one here.


EDITORIAL NOTE: The content provided by the Science of Parkinson’s website is for information purposes only. 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. The information provided on this website should under no circumstances be considered medical advice, and any actions taken by readers should firstly be discussed with a qualified healthcare professional.


The banner for today’s post was sourced from NRF2 science

The benefits (???) of Antioxidants

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It seems everyday we read stories in the media about the benefits of these things called antioxidants. We are repeatedly told that we ‘need more antioxidants in our diet’, because they will help to stave off debilitating conditions like Parkinson’s disease.

Last week, however, a study was published which indicates that this may not be the case.

In todays post we look at antioxidants and their impact on Parkinson’s disease.


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Berries are a wonderful source of antioxidants. Source: Steroidal

Antioxidants are one of those subjects that is often discussed, but not well understood. So before we review the study that was published last week, let’s first have a look at what we mean when we talk about antioxidants.

What is an antioxidant?

An antioxidant is simply a molecule that prevents the oxidation of other molecules.

OK, but what does that mean?

Well, the cells in your body are made of molecules. Molecules are combinations atoms of one or more elements joined by chemical bonds. Atoms consist of a nucleus, neutrons, protons and electrons.

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.

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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.

What is a free radical?

A free radical is an unstable molecule – unstable because they are missing electrons. They react quickly with other molecules, trying to capture the needed electron to re-gain stability. Free radicals will literally attack the nearest stable molecule, stealing 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.

Antioxidants are thus the good guys in this situation. They are molecules that neutralize free radicals by donating one of their own electrons. The antioxidant don’t become free radicals by donating an electron because by their very nature they are stable with or without that extra electron.

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How free radicals and antioxidants work. Source: h2miraclewater

What are good sources of antioxidants?

While human being are pretty poor at producing antioxidants, plants produce LOTS! Thus vegetables and fruits are a fantastic source of antioxidants.

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Sources of antioxidants (no. 3 is our favourite). Source: DrAxe

The Oxygen radical absorbance capacity (ORAC) score mentioned in the figure above is a method of measuring the antioxidant capacity of various substances. For comparative sake, a piece of tofu has an ORAC score of approximately 90, a beef steak has an ORAC score of approximately 10, and a ‘Redbull’ energy drink has an ORAC score of 0 (as they all have very few antioxidants – Source:Superfoodly).

A source of major antioxidants are vitamins (such as beta-carotene, vitamin C, and vitamin E). Vitamins are essential nutrients that our bodies needs (in small amounts) to function properly. Many of them are also potent antioxidants.

Vitamin C (or ascorbic acid), in particular, is a powerful antioxidant and it is found in both animals and plants. Unfortunately for humans, however, one of the enzymes needed to make ascorbic acid was lost by a genetic mutation during primate evolution, and so we must obtain it from our diet (eat lots of oranges folks).

How could antioxidants work for Parkinson’s disease?

 

Postmortem analysis of the brains of people who had Parkinson’s disease has revealed numerous signs of oxidative damage, and this has lead to many researchers hypothesising that oxidation is a key component of the disease.

So what research was published last week?

The results of this study:

titlegts

Title: Intake of antioxidant vitamins and risk of parkinson’s disease.
Authors: Hughes KC, Gao X, Kim IY, Rimm EB, Wang M, Weisskopf MG, Schwarzschild MA, Ascherio A.
Journal: Movement Disorders. 2016 Oct 27. doi: 10.1002/mds.26819.
PMID: 27787934

In this study, the investigators wanted to look at the consumption of antioxidant vitamins and the risk of developing Parkinson’s disease. In order to do this, they needed large pools of medical data that they could analyse. They used the databases from the Nurses’ Health Study (NHS) and the Health Professionals Follow-Up Study (HPFS) in the USA.

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.

The investigators in the current study, removed the data from people who reported ‘implausible total energy intake at baseline (<660 or >3,500 kcal/day for women and <800 or >4,200 kcal/day for men)’, missed reporting for any survey, or had a diagnosis of Parkinson’s disease at the start of the study. This left them with the survey results of 80,750 women and 48,672 men to analyse.

From these pools of subjects, they found a total of 1036 people with Parkinson’s disease (554 in HPFS and 482 in NHS). When the investigators looked at antioxidant vitamin consumption, they found that vitamin E was not associated with an increased or decreased risk of Parkinson’s disease. Vitamin C intake showed indications of reducing the risk of developing Parkinson’s, but this not significant.

The investigators concluded that their results do not support the hypothesis that consumption of antioxidant vitamins reduces the risk of Parkinson’s disease.

What about other Parkinson’s disease research on antioxidants?

There have been several clinical trials for antioxidants and Parkinson’s disease. Of particular interest has been the research surrounding Coenzyme Q10 (also known as ubiquinone and ubidecarenone).Coenzyme Q10 is an antioxidant that exhibited positive preclinical results for Parkinson’s disease, and this led to several large clinical trials:

coenzym

Title: A randomized clinical trial of high-dosage coenzyme Q10 in early Parkinson disease: no evidence of benefit.
Authors: Parkinson Study Group QE3 Investigators., Beal MF, et al.
Journal: JAMA Neurol. 2014 May;71(5):543-52.
PMID: 24664227

This article reported the results of a phase III randomized, placebo-controlled, double-blind clinical trial at 67 North American sites, consisting of 600 participants. While Coenzyme Q10 was safe and well tolerated by the subjects in the study, it demonstrated no evidence of clinical benefit.

One justified critique of this study, however, was the variety of subjects with Parkinson’s disease involved in the study. It has been suggested that a clinical trial should be performed with coenzyme Q10 in people with Parkinson’s disease who have a proven mutation in the PINK1 gene as these are the subjects who are most likely to benefit from this approach. That would be an interesting trial.

So what does it all mean?

Well, the study published last week needs to be replicated with another large database before any serious conclusions can be made. For all the hype around antioxidants, however, there is a worrying lack of supporting evidence that they actually have any effect (in the case of lung cancer there are even suggestions that some vitamin antioxidants could exacerbate the situation – click here for more on this).

The results of the study reviewed above do suggest that our view of oxidation in Parkinson’s disease needs to be re-addressed. It may be that oxidation may simply be an end step in the condition, and trying to block it with antioxidants is fruitless.

It should be noted that we are not suggesting here that people should stop taking antioxidants – they are an important part of any balanced diet, necessary for normal biological functioning. We are simply presenting the evidence that some of the hype surrounding their potential is unfounded.

As usual, as more information comes to hand, we shall present it here. Watch this space.


The banner for todays post was sourced from Pinkhope