The protein Alpha Synuclein has long been considered the bad-boy of Parkinson’s disease research. Possibly one of the main villains in the whole scheme of things.
New research suggests that it may be interfering with a neuroprotective pathway, leaving the affected cell more vulnerable to stress/toxins. But that same research has highlighted a novel beneficial feature of an old class of drugs: MAO-B inhibitors.
In today’s post we will outline the new research, discuss the results, and look at whether this new Trk warrants a re-think of MAO-B inhibitors.
The great Harry Houdini. Source: Wikipedia
I’m not sure about you, but I enjoy a good magic trick.
That exhilarating moment when you are left wondering just one thing: How do they do that?
(Seriously, at 4:40 a baguette comes out of thin air – how did he do that?)
Widely believed to have been one of the greatest magicians of all time (Source), Harry Houdini is still to this day revered among those who practise the ‘dark arts’.
Born Erik Weisz in Budapest (in 1874), Houdini arrived in the US in 1878. Fascinated with magic, in 1894, he launched his career as a professional magician and drew attention for his daring feats of escape. He renamed himself “Harry Houdini” – the first name being derived from his childhood nickname, “Ehrie,” and the last name paying homage to the great French magician Jean Eugène Robert-Houdin. In 1899, Houdini’s act caught the eye of Martin Beck, an entertainment manager, and from there the rest is history. Constantly upping the ante, his feats became bolder and more death defying.
And the crowds loved him.
From stage, he moved on to film – ultimately starting his own production company, Houdini Picture Corporation. In addition, he was a passionate debunker of psychics and mediums, his training in magic helping him to expose frauds (which turned him against his former friend Sir Arthur Conan Doyle, who believed deeply in spiritualism).
This is all very interesting, but what does any of it have to do with Parkinson’s?
In a recent post, I discussed research looking at foods that can influence the progression of Parkinson’s (see that post here). I am regularly asked about the topic of food and will endeavour to highlight more research along this line in future post.
In accordance with that statement, today we are going to discuss Cruciferous vegetables, and why we need a clinical trial of broccoli.
I’m not kidding.
There is growing research that a key component of broccoli and other cruciferous vegetables – called Glucoraphanin – could have beneficial effects on Parkinson’s disease. In today’s post, we will discuss what Glucoraphanin is, look at the research that has been conducted and consider why a clinical trial of broccoli would be a good thing for Parkinson’s disease.
Cruciferous vegetables. Source: Diagnosisdiet
Like most kids, when I was young I hated broccoli.
Man, I hated it. With such a passion!
Usually they were boiled or steamed to the point at which they have little or no nutritional value, and they largely became mush upon contact with my fork.
The stuff of my childhood nightmares. Source: Modernpaleo
As I have matured (my wife might debate that statement), my opinion has changed and I have come to appreciate broccoli. Our relationship has definitely improved.
In fact, I have developed a deep appreciation for all cruciferous vegetables.
And yeah, I know what you are going to ask:
What are cruciferous vegetables?
Cruciferous vegetables are vegetables of the Brassicaceae family (also called Cruciferae). They are a family of flowering plants commonly known as the mustards, the crucifers, or simply the cabbage family. They include cauliflower, cabbage, garden cress, bok choy, broccoli, brussels sprouts and similar green leaf vegetables.
Cruciferous vegetables. Source: Thetherapyshare
So what have Cruciferous vegetables got to do with Parkinson’s?
Well, it’s not the vegetables as such that are important. Rather, it is a particular chemical that this family of plants share – called Glucoraphanin – that is key.
What is Glucoraphanin?
The motor features of Parkinson’s disease can be managed with treatments that replace the chemical dopamine in the brain.
While there are many medically approved dopamine replacement drugs available for people affected by Parkinson’s disease, there also are more natural sources.
In today’s post we will look at the science and discuss the research supporting one of the most potent natural source for dopamine replacement treatment: Mucuna pruriens
When asked by colleagues and friends what is my ‘plan B’ (that is, if the career in academia does not play out – which is highly probable I might add – Click here to read more about the disastrous state of biomedical research careers), I answer that I have often considered throwing it all in and setting up a not-for-profit, non-governmental organisation to grow plantations of a tropical legume in strategic places around the world, which would provide the third-world with a cheap source of levodopa – the main treatment in the fight against Parkinson’s disease.
Plan B: A legume plantation. Source: Tropicalforages
The response to my answer is generally one of silent wonder – that is: me silently wondering if they think I’m crazy, and them silently wondering what on earth I’m talking about.
As romantic as the concept sounds, there is an element of truth to my Plan B idea.
I have read many news stories and journal articles about the lack of treatment options for those people with Parkinson’s disease living in the developing world.
Hospital facilities in the rural Africa. Source: ParkinsonsLife
Some of the research articles on this topic provide a terribly stark image of the contrast between people suffering from Parkinson’s disease in the developing world versus the modernised world. A fantastic example of this research is the work being done by the dedicated researchers at the Parkinson Institute in Milan (Italy), who have been conducting the “Parkinson’s disease in Africa collaboration project”.
The researchers at the Parkinson Institute in Milan. Source: Parkinson Institute
The project is an assessment of the socio-demographic, epidemiological, clinical features and genetic causes of Parkinson’s disease in people attending the neurology out-patients clinic of the Korle Bu Teaching and Comboni hospitals. Their work has resulted in several really interesting research reports, such as this one:
Title: The modern pre-levodopa era of Parkinson’s disease: insights into motor complications from sub-Saharan Africa.
Authors: Cilia R, Akpalu A, Sarfo FS, Cham M, Amboni M, Cereda E, Fabbri M, Adjei P, Akassi J, Bonetti A, Pezzoli G.
Journal: Brain. 2014 Oct;137(Pt 10):2731-42.
PMID: 25034897 (This article is OPEN ACCESS if you would like to read it)
In this study, the researchers collected data in Ghana between December 2008 and November 2012, and each subject was followed-up for at least 6 months after the initiation of Levodopa therapy. In total, 91 Ghanaians were diagnosed with Parkinson’s disease (58 males, average age at onset 60 ± 11 years), and they were compared to 2282 Italian people with Parkinson’s disease who were recruited during the same period. In long-term follow up, 32 Ghanaians with Parkinson’s disease were assessed (with an average follow period of 2.6 years).
There are some interesting details in the results of the study, such as:
- Although Levodopa therapy was generally delayed – due to availability and affordability – in Ghana (average disease duration before Levodopa treatment was 4.2 years in Ghana versus just 2.4 years in Italy), the actual disease duration – as determined by the occurrence of motor fluctuations and the onset of dyskinesias – was similar in the two populations.
- The motor fluctuations were similar in the two populations, with a slightly lower risk of dyskinesias in Ghanaians.
- Levodopa daily doses were higher in Italians, but this difference was no longer significant after adjusting for body weight.
- Ghanaian Parkinson’s sufferers who developed dyskinesias were younger at onset than those who did not.
Reading these sorts of research reports, I am often left baffled by the modern business world’s approach to medicine. I am also left wondering how an individual’s experience of Parkinson’s disease in some of these developing nations would be improved if a cheap alternative to the dopamine replacement therapies was available.
Are any cheap alternatives available?
In addition to looking at current Parkinson’s disease research on this website, I like to look at where technological advances are taking us with regards to future therapies.
In July of this year, I wrote about a new class of engineered viruses that could potentially allow us to treat conditions like Parkinson’s disease using a non-invasive, gene therapy approach (Click here to read that post). At the time I considered this technology way off at some point in the distant future. Blue sky research. “Let’s wait and see” – sort of thing.
So imagine my surprise when an Italian research group last weekend published a new research report in which they used this futurist technology to correct a mouse model of Parkinson’s disease. Suddenly the distant future is feeling not so ‘distant’.
In today’s post we will review and discuss the results, and look at what happens next.
Technological progress – looking inside the brain. Source: Digitial Trends
I have said several times in the past that the pace of Parkinson’s disease research at the moment is overwhelming.
So much is happening so quickly that it is quite simply difficult to keep up. Not just here on the blog, but also with regards to the ever increasing number of research articles in the “need to read” pile on my desk. It’s mad. It’s crazy. Just as I manage to digest something new from one area of research, two or three other publications pop up in different areas.
But it is the shear speed with which things are moving now in the field of Parkinson’s research that is really mind boggling!
Take for example the case of Squalamine.
In February of this year, researchers published an article outlining how a drug derived from the spiny dogfish could completely suppress the toxic effect of the Parkinson’s associated protein Alpha Synuclein (Click here to read that post).
The humble dogfish. Source: Discovery
And then in May (JUST 3 MONTHS LATER!!!), a biotech company called Enterin Inc. announced that they had just enrolled their first patient in the RASMET study: a Phase 1/2a randomised, controlled, multi-center clinical study evaluating a synthetic version of squalamine (called MSI-1436) in people with Parkinson’s disease. The study will enrol 50 patients over a 9-to-12-month period (Click here for the press release).
Wow! That is fast.
Yeah, I thought so too, but then this last weekend a group in Italy published new research that completely changed my ideas on the meaning of the word ‘fast’. Regular readers will recall that in July I discussed amazing new technology that may one day allow us to inject a virus into a person’s arm and then that virus will make it’s way up to the brain and only infect the cells that we want to have a treatment delivered to. This represents non-invasive (as no surgery is required), gene therapy (correcting a medical condition with the delivery of DNA rather than medication). This new study used the same virus we discussed in July.
In my previous post, we briefly reviewed the results of the phase II double-blind, randomised clinical trial of Exenatide in Parkinson’s disease. The study indicates a statistically significant effect on motor symptom scores after being treated with the drug.
Over the last few days, there have been many discussions about the results, what they mean for the Parkinson’s community, and where things go from here, which have led to further questions.
In this post I would like to address several matters that have arisen which I did not discuss in the previous post, but that I believe are important.
I found out about the Exenatide announcement – via whispers online – on the afternoon of the release. And it was in a mad rush when I got home that night that I wrote up the post explaining what Exenatide is. I published the post the following evening however because I could not access the research report from home (seriously guys, biggest finding in a long time and it’s not OPEN ACCESS?!?!?) and I had to wait until I got to work the next day to actually view the publication.
I was not really happy with the rushed effort though and decided to follow up that post. In addition, there has been A LOT of discussion about the results over the weekend and I thought it might be good to bring aspects of those different discussion together here. The individual topics are listed below, in no particular order of importance:
1. Size of the effect
There are two considerations here.
Firstly, there have been many comments about the actual size of the effect in the results of the study itself. When people have taken a deeper look at the findings, they have come back with questions regarding those findings.
And second, there have also been some comments about the size of the effect that this result has already had on the Parkinson’s community, which has been considerable (and possibly disproportionate to the actual result).
The size of the effect in the results
The results of the study suggested that Exenatide had a positive effect on the motor-related symptoms of Parkinson’s over the course of the 60 week trial. This is what the published report says, it is also what all of the media headlines have said, and it sounds really great right?
The main point folks keep raising, however, is that the actual size of the positive effect is limited to just the motor features of Parkinson’s disease. If one ignores the Unified Parkinson’s Disease Rating Scale (UPDRS) motor scores and focuses on the secondary measures, there isn’t much to talk about. In fact, there were no statistically significant differences in any of the secondary outcome measures. These included:
For many people diagnosed with Parkinson’s disease, one of the scariest prospects of the condition that they face is the possibility of developing dyskinesias.
Dyskinesias are involuntary movements that can develop after long term use of the primary treatment of Parkinson’s disease: Levodopa
In todays post I discuss one experimental strategy for dealing with this debilitating aspect of Parkinson’s disease.
Dyskinesia. Source: JAMA Neurology
There is a normal course of events with Parkinson’s disease (and yes, I am grossly generalising here).
First comes the shock of the diagnosis.
This is generally followed by the roller coaster of various emotions (including disbelief, sadness, anger, denial).
Then comes the period during which one will try to familiarise oneself with the condition (reading books, searching online, joining Facebook groups), and this usually leads to awareness of some of the realities of the condition.
One of those realities (especially for people with early onset Parkinson’s disease) are dyskinesias.
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 I have suggested in the summary at the top, they are associated in Parkinson’s disease with long-term use of Levodopa (also known as Sinemet or Madopar).
Sinemet is Levodopa. Source: Drugs
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.
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. 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?
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.
A major trend in experimental medicine at present is ‘immunotherapy‘ – stimulating or reprogramming the immune system to help fight particular diseases.
A research group in Nebraska have attempted to use this approach for Parkinson’s disease, and recently they have published some very interesting clinical trial results.
In today’s post, we will discuss the science and review the results of their research.
Nebraska. Source: The Toast
Here at the SoPD HQ, we like surprises.
And when several readers contacted us about some interesting results from a new clinical trial for Parkinson’s disease that we knew nothing about, we were rather ‘OMG! What a fantastic surprise!’ about it.
The results stem from a clinical trial that has taken a rather different approach to tackling Parkinson’s disease: boosting the immune system to help fight off the condition. And rather than simply covering up the symptoms, the drug being tested may actually slow down the condition.
You may have heard about this trial as the results of this clinical study have attracted the attention of the media:
So what was the new clinical trial all about?
Let’s start with the context of the study. You see, it took place in the great US state of Nebraska.
Interesting place Nebraska.
Nebraska (in red). Source: Wikipedia
And home to the largest porch swing in the world (holds 18 adults or 24 children – amazing).
The world’s largest swing chair. Source: Pinterest
Nebraska is also one of the top agricultural states in the USA, with about 93% of the land being used for farming. And approximately 40% of the state’s population (750,000 out of 1.8 million) lives in those rural areas. As a result of this largely rural population, there are probably a lot of people in Nebraska being exposed to pesticide and insecticides (in the air they breath and the water they drink).
This exposure is believed to be one of the reasons why Nebraska has one of the highest rates of Parkinson’s disease in the USA.
There are approximately 330 people per 100,000 of the general population living with Parkinson’s Disease in Nebraska (Click here for more on this). Compare that with just 180 people per 100,000 of the UK general population having Parkinson’s Disease (Click here for more on this).
As a result of this statistic, Parkinson’s disease is taken very seriously in Nebraska.
There is also a lot of Parkinson’s disease research being conducted there.
And this brings us to the clinical study results we are going to discuss:
Title:Evaluation of the safety and immunomodulatory effects of sargramostim in a randomized, double-blind phase 1 clinical Parkinson’s disease trial
Authors: Gendelman HE, Zhang Y, Santamaria P, Olson KE, Schutt CR, Bhatti D, Shetty BLD, Lu Y, Estes KA, Standaert DG, Heinrichs-Graham E, Larson L, Meza JL, Follett M, Forsberg E, Siuzdak G, Wilson TW, Peterson C, & Mosley RL
Journal: npj Parkinson’s Disease (2017) 3, 10.
PMID: N/A (This article is OPEN ACCESS if you would like to read it)
For this randomised, double-blind phase 1 clinical trial, the researchers enrolled 20 people with Parkinson’s disease and 17 age-matched non-Parkinsonian control subjects. The people with Parkinson’s disease ranged in age from 53 to 76 years (mean age of 64) and they had had symptoms for 3–14 years (the mean was 7 years). Both the Parkinson’s disease group and control group were monitored for 2 months before the trial started in order to establish baseline measurements and profiles.
The Parkinson’s disease group were then randomly assigned into two equal sized groups (10 subjects each) and they were then self-administered (by self-injection) either sargramostim (6 μg/kg/day) or a placebo control solution (saline) for 56 days (click here to see the details of the clinical trial).
Hang on a second, what is Sargramostim?
Sargramostim (marketed by the pharmaceutical company Genzyme under the tradename ‘Leukine’) is an Food and Drug Administration (FDA) -approved recombinant granulocyte macrophage colony-stimulating factor (GM-CSF) that functions as an immunostimulator.
What…on earth…..does any of that….actually mean?
Ok, so Food and Drug Administration (FDA) -approved means that this drug is safe to use in humans. Sargramostim is currently widely used in bone marrow transplantation procedures, to stimulate the production of new blood cells.
‘Recombinant‘ basically means that we are talking about an artificially produced protein.
‘Granulocyte macrophage colony-stimulating factor‘ is an actual protein that our bodies produce. GM-CSF is a small protein that is secreted by various types of cells in our body, and it functions as a cytokine. And yes, I know what you are going to ask:
What’s a cytokine?
Cytokines (from the Greek: kýtos meaning ‘container, body, cell’; and kī́nēsis meaning ‘movement’) are small proteins that are secreted by certain cells in the body and they have an effect on other cells. Cytokines are a method of communication for cells.
How cytokines work. Source: SBS
Granulocyte macrophage colony-stimulating factor is secreted by various cells around the body to communicate with the immune system that something is wrong. In it’s actually function, GM-CSF acts as a white blood cell growth factor, or a stimulant of white blood cell production.
GM-CSF stimulates blood stem cells into production. Source: Oxymed
Why are white blood cells important?
While red blood cells are principally involved with the delivery of oxygen to the various parts of the body, the white blood cells (also referred to as leukocytes or leucocytes), are the cells of your immune system that protect your body against both infectious disease and foreign invaders.
6 types of white blood cells. Source: Stfranciscare
GM-CSF stimulates blood stem cells to produce more neutrophils, eosinophils, basophils, and monocytes (all types of white blood cells – see image above). Monocytes then migrate towards the tissue affected by the injury or disease, where they then mature into macrophages and dendritic cells (Macrophages are large, specialised cells that are responsible for removing damaged target cells).
Once at the site of trouble, macrophages produce pro-inflammatory neurotoxins that help to destroy unhealthy or damaged cells, making them easier to engulf and dispose of. The problem is that those released neurotoxins can also damage surrounding healthy cells.
Given that GM-CSF stimulates this kind of activity, you are probably wondering why researchers would be giving Sargramostim to folks with Parkinson’s disease.
But GM-CSF also does something else that is really interesting:
GM-CSF stimulates regulatory T (Treg) cells.
What are regulatory T cells?
Regulatory T (Treg) cells maintain order in the immune system. They do this by enforcing a dominant negative regulation on other immune cells, particularly other T-cells.
T-cells are a type of white blood cell that circulate around our bodies, scanning for cellular abnormalities and infections.
Think of T-cells as the inquisitive neighbours curious about and snooping around a local crime scene, and then imagine that Treg cells are the police telling them “nothing to see here, move along”.
Tregs maintaining order. Source: Keywordsuggestions
Treg cells are particularly important for calming down effector T cells (or T-eff cells). These are several different types of T cell types that ‘actively’ respond to a stimulus. They include:
- Helper T cells (TH cells) which assist other white blood cells in the immunological process
- Killer T cells which destroy virus-infected cells, tumor cells, and are involve in transplant rejection.
The normal situation in the body is to have a balance between T-eff cells and Treg cells. If there are too many T-eff cells, there is increased chances of autoimmunity – or the immune system attacking healthy cells.
A delicate balance between healthy and autoimmune disease. Source: Researchgate
Too many Treg cells is not a good situation either, however, as they would leave the immune system suppressed and individuals vulnerable to disease.
How are Treg cells involved with Parkinson’s disease?
So, in Parkinson’s disease, researchers believe that the build up of the Parkinson’s associated protein, alpha synuclein may be toxic and killing certain cells in the brain (such as the dopamine neurons). When the cell dies and the alpha synuclein is released into the surrounding environment of the brain, it most likely does two things:
- irritates and activates the resident immune cells, called microglia
- activates the wider immune system, resulting in T-cell infiltration of the brain
The T-cells snoop around, detect that something isn’t quite right and then release their own cytokines which further activates the microglia. The microglia then release pro-inflammatory toxic chemicals which indiscriminately damage the unhealthy and healthy cells in the local area.
A.) The normal situation in PD; B.) the situation after GM-CSF treatment. Source: NCBI
Now the hypothesis is that GM-CSF may be able mediate this degenerative cycle by stimulating the induction of Treg cells, which can calm the activated microglia down, return it to a resting state and the healthy surrounding neurons survive intact.
Is there any research evidence for this effect in models of Parkinson’s disease?
Yes there is.
The group in Nebraska have actually been working ‘pre-clinically’ on this idea for some time:
Title: Neuroprotective activities of CD4+CD25+ regulatory T cells in an animal model ofParkinson’s disease.
Authors: Reynolds AD, Banerjee R, Liu J, Gendelman HE, Mosley RL.
Journal: J Leukoc Biol. 2007 Nov;82(5):1083-94.
In this study, the researchers demonstrated that by increasing the number of activated Treg cells in neurotoxin (MPTP)-injected mice, they could produce a greater than 90% level of protection of the dopamine neurons when compared to mice that did not receive the increase of Treg cells.
The Treg cells were found to mediate this neuroprotection through suppression of the microglial response to the neurotoxin. The investigators concluded that their data strongly supported the use of immunomodulation as a strategy for treating Parkinson’s.
They next extended these findings by looking at whether GM-CSF could provide neuroprotection in the same model of Parkinson’s disease:
Title: GM-CSF induces neuroprotective and anti-inflammatory responses in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine intoxicated mice.
Authors: Kosloski LM, Kosmacek EA, Olson KE, Mosley RL, Gendelman HE.
Journal: J Neuroimmunol. 2013 Dec 15;265(1-2):1-10.
PMID: 24210793 (This article is OPEN ACCESS if you would like to read it)
In this study, the researchers gave GM-CSF prior to the neurotoxin (MPTP) which kills dopamine neurons. GM-CSF freely cross the blood-brain barrier which inhibits a lot of other drugs from entering the brain. This treatment protected the dopamine neurons and the investigators found increased Treg induction and reduced activation of the microglia cells.
This neuroprotective effect could also transferred between animals. Treg cells from GM-CSF treated mice were transferred to MPTP-treated mice and neuroprotection of the dopamine neurons was observed in those animals. The researchers concluded that the results provide evidence that GM-CSF modulation of the immune system could be of clinical benefit for people with Parkinson’s disease.
And they are not the only investigators who have demonstrated this. In addition to the work produced by the Nebraskan research team, other research groups have also observed beneficial effects of GM-CSF in models of Parkinson’s disease (Click here, here and here to read some of those reports).
In fact, for a very good OPEN ACCESS review on the topic of immunomodulation for Parkinson’s disease – click here.
And with all of this research backing them, the team in Nebraska decided to move GM-CSF towards the clinic with a small phase I clinical trial.
The Nebraska team: Dr Howard Gendelman, Dr Pamela Santamaria & Prof R. Lee Mosley. Source: Omaha
What did they find in the clinical trial?
In their randomized, double-blind, phase 1 clinical trial of 20 people with Parkinson’s disease taking either sargramostim (10 subjects) or a placebo control solution (10 subjects) for 56 days, the researchers found that Sargramostim firstly increases the the induction of Treg cells, and mediated suppression of the immune cells
More importantly, the sargramostim treated group demonstrated a modest improvement in their motor performance scores after 6 and 8 weeks of treatment when compared with the placebo group. The study was not large enough in size or duration for robust conclusions to be made, but the deviation between the two groups in motor scores in intriguing. This is particularly curious given that the sargramostim treatment group returned to a similar level of performance as the control (placebo) group at the 8 week assessment when they were no longer on sargramostim:
Change in motor scores of the participants. Source: Nature
One of the interesting features of this study was that the participants were a mixed bunch with regards to their Parkinson’s disease. The participants ranged in age from 53 to 76 years (mean age of 64) and they had had symptoms for 3–14 years (the mean was 7 years). It would be interesting to know (in a larger study) if there is any difference in the effect of this treatment based on length of time since diagnosis.
Another interesting aspect of the study is that it was double-blind. It is rather rare for a phase I clinical study to be double-blind, as they are usually just testing safety and tolerance. But given that sargramostim is used in the clinic already, the investigators had more flexibility with the study design. The double blind nature of the results only makes the findings more intriguing though.
The next step in this research is to plan a larger clinical study in 1-2 years time. The delay is caused by the desire for that trial to focus on an oral tablet (currently Sargramostim is only administered via an injection – not a popular route!). Those follow up studies will require groups taking different doses of the drug to get a better idea of effective dosages.
So what does it all mean?
Artificial modulation of the immune system represents tremendous opportunities for not only Parkinson’s disease, but also other conditions such as Alzheimer’s disease and amyotrophic lateral sclerosis. Recently, some researchers have concluded a clinical study of immunomodulation for Parkinson’s disease after almost 20 years of preclinical experimentation. The results are very interesting and may provide us with a novel method of treating the condition.
We here at the SoPD will be interested to see if Sargramostim makes it through the clinical testing process alone (as a “mono-therapy”) for Parkinson’s disease, or whether it will be used in combination with other drugs. One potential issue for this approach is that it leaves the individual with a suppressed immune system to defend them against other infectious agents.
Having said that, the fact that this approach may work could also tell us a great deal about the nature of Parkinson’s disease itself, and raising the idea that the body’s immune response could be involved with the progression of this neurodegenerative condition. We already know from several studies that certain anti-inflammation drugs (particularly Ibuprofen) can help to lower the risk of developing Parkinson’s disease (Click here for more on Ibuprofen).
Perhaps while we wait for the pill version of Sargramostim, a separate Ibuprofen study could be conducted to determine if this drug could slow down the progression of the disease.
The banner for today’s post was sourced from Diamond