Gene therapy involves treating medical conditions at the level of DNA – that is, altering or enhancing the genetic code inside cells to provide therapeutic benefits rather than simply administering drugs. Usually this approach utilises specially engineered viruses to deliver the new DNA to particular cells in the body.
For Parkinson’s, gene therapy techniques have all involved direct injections of these engineered viruses into the brain – a procedure that requires brain surgery. This year, however, we have seen the EXTREMELY rapid development of a non-invasive approach to gene therapy for neurological condition, which could ultimately see viruses being injected in the arm and then travelling up to the brain where they will infect just the desired population of cells.
Last week, however, this approach hit a rather significant obstacle.
In today’s post, we will have a look at this gene therapy technology and review the new research that may slow down efforts to use this approach to help to cure Parkinson’s.
Gene therapy. Source: rdmag
When you get sick, the usual solution is to visit your doctor.
They will prescribe a medication for you to take, and then all things going well (fingers crossed/knock on wood) you will start to feel better. It is a rather simple and straight forward process, and it has largely worked well for most of us for quite some time.
As the overall population has started to live longer, however, we have begun to see more and more chronic conditions which require long-term treatment regimes. The “long-term” aspect of this means that some people are regularly taking medication as part of their daily lives. In many cases, these medications are taken multiple times per day.
A good example of this is Levodopa (also known as Sinemet or Madopar) which is the most common treatment for the chronic condition of Parkinson’s disease.
When you swallow your Levodopa pill, it is broken down in the gut, absorbed through the wall of the intestines, transported to the brain via our blood system, where it is converted into the chemical dopamine – the chemical that is lost in Parkinson’s disease. This conversion of Levodopa increases the levels of dopamine in your brain, which helps to alleviate the motor issues associated with Parkinson’s disease.
Levodopa. Source: Drugs
This pill form of treating a disease is only a temporary solution though. People with Parkinson’s – like other chronic conditions – need to take multiple tablets of Levodopa every day to keep their motor features under control. And long term this approach can result in other complications, such as Levodopa-induced dyskinesias in the case of Parkinson’s.
Yeah, but is there a better approach?
In this post we discuss several recently published research reports suggesting that Parkinson’s disease may be an autoimmune condition. “Autoimmunity” occurs when the defence system of the body starts attacks the body itself.
This new research does not explain what causes of Parkinson’s disease, but it could explain why certain brain cells are being lost in some people with Parkinson’s disease. And such information could point us towards novel therapeutic strategies.
The first issue of Nature. Source: SimpleWikipedia
The journal Nature was first published on 4th November 1869, by Alexander MacMillan. It hoped to “provide cultivated readers with an accessible forum for reading about advances in scientific knowledge.” It has subsequently become one of the most prestigious scientific journals in the world, with an online readership of approximately 3 million unique readers per month (almost as much as we have here at the SoPD).
Each Wednesday afternoon, researchers around the world await the weekly outpouring of new research from Nature. And this week a research report was published in Nature that could be big for the world of Parkinson’s disease. Really big!
On the 21st June, this report was published:
Title: T cells from patients with Parkinson’s disease recognize α-synuclein peptides
Authors: Sulzer D, Alcalay RN, Garretti F, Cote L, Kanter E, Agin-Liebes J, Liong C, McMurtrey C, Hildebrand WH, Mao X, Dawson VL, Dawson TM, Oseroff C, Pham J, Sidney J, Dillon MB, Carpenter C, Weiskopf D, Phillips E, Mallal S, Peters B, Frazier A, Lindestam Arlehamn CS, Sette A
Journal: Nature. 2017 Jun 21. doi: 10.1038/nature22815.
In their study, the investigators collected blood samples from 67 people with Parkinson’s disease and from 36 healthy patients (which were used as control samples). They then exposed the blood samples to fragments of proteins found in brain cells, including fragments of alpha synuclein – this is the protein that is so closely associated with Parkinson’s disease (it makes regular appearances on this blog).
What happened next was rather startling: the blood from the Parkinson’s patients had a strong reaction to two specific fragments of alpha synuclein, while the blood from the control subjects hardly reacted at all to these fragments.
In the image below, you will see the fragments listed along the bottom of the graph (protein fragments are labelled with combinations of alphabetical letters). The grey band on the plot indicates the two fragments that elicited a strong reaction from the blood cells – note the number of black dots (indicating PD samples) within the band, compared to the number of white dots (control samples). The numbers on the left side of the graph indicate the number of reacting cells per 100,000 blood cells.
The investigators concluded from this experiment that these alpha synuclein fragments may be acting as antigenic epitopes, which would drive immune responses in people with Parkinson’s disease and they decided to investigate this further.
Today there was a lot of Parkinson’s related activity in the news… well, more than usual at least.
Overnight there was the publication of a blood test for Parkinson’s disease, which looks very sensitive. And this afternoon, Acorda Therapeutics announced positive data for their phase three trial.
In this post, we’ll look at what it all means.
Blood cells. Source: Reference.com
Today we found out about an interesting new study from scientists at Lund University (Sweden), where they are developing a test that can differentiate between different types of Parkinsonisms (See our last post about this) using a simple blood test.
We have previously reported about an Australian research group working on a blood test for Parkinson’s disease, but they had not determined whether their test could differentiate between different kinds of neurodegenerative conditions (such as Alzheimer’s disease). And this is where the Swedish study has gone one step further…
Title: Blood-based NfL: A biomarker for differential diagnosis of parkinsonian disorder
Authors: Hansson O, Janelidze S, Hall S, Magdalinou N, Lees AJ, Andreasson U, Norgren N, Linder J, Forsgren L, Constantinescu R, Zetterberg H, Blennow K, & For the Swedish BioFINDER study
Journal: Neurology, Published online before print February 8, 2017
PMID: N/A (This article is OPEN ACCESS if you would like to read it)
The research group in Lund had previously demonstrated that they could differentiate between people with Parkinson’s disease and other types of Parkinsonism to an accuracy of 93% (Click here to read more on this). That is a pretty impressive success rate – equal to basic clinical diagnostic success rates (click here for more on this).
The difference was demonstrated in the levels of a particular protein, neurofilament light chain (or Nfl). NfL is a scaffolding protein, important to the cytoskeleton of neurons. Thus when cells die and break up, Nfl could be released. This would explain the rise in Nfl following injury to the brain. Other groups (in Germany and Switzerland) have also recently published data suggesting that Nfl could be a good biomarker of disease progression (Click here to read more on this).
There was just one problem: that success rate we were talking about above, it required cerebrospinal fluid. That’s the liquid surrounding your brain and spinal cord, which can only be accessed via a lumbar puncture – a painful and difficult to perform procedure.
Lumbar puncture. Source: Lymphomas Assoc.
Not a popular idea.
This led the Swedish researchers to test a more user friendly approach: blood.
In the current study, the researchers took blood samples from three sets of subjects:
- A Lund set (278 people, including 171 people with Parkinson’s disease (PD), 30 people with Multiple system atrophy (MSA), 19 people with Progressive Supranuclear Palsy (PSP), 5 people with corticobasal syndrome (CBS), and 53 people who were neurologically healthy (controls).
- A London set (117 people, including 20 people with PD, 30 people with MSA, 29 people with PSP, 12 people with CBS, and 26 neurologically healthy controls
- An early disease set (109 people, including 53 people with PD, 28 people with MSA, 22 people with PSP, 6 people with CBS). All of the early disease set had a disease duration less than 3 years.
When the researchers looked at the levels of NfL in blood, they found that they could distinguish between people with PD and people with PSP, MSA, and CBS with an accuracy of 80-90% – again a very impressive number!
One curious aspect of this finding, however, is that the levels of Nfl in people with PD are very similar to controls. So while this protein could be used to differentiate between PD and other Parkinsonisms, it may not be a great diagnostic aid for determining PD verses non-PD/healthy control.
In addition, what could the difference in levels of Nfl between PD and other Parkinsonisms tell us about the diseases themselves? Does PD have less cell death, or a more controlled and orderly cell death (such as apoptosis) than the other Parkinsonisms? These are questions that can be examined in follow up work.
Like we said at the top, it’s been a busy day for Parkinson’s disease: Good news today for Acorda Therapeutics, Inc.
They announced positive Phase 3 clinical trial results for their inhalable L-dopa treatment, called CVT-301, which demonstrated a statistically significant improvement in motor function in people with Parkinson’s disease experiencing OFF periods.
We have previously discussed the technology and the idea behind this approach to treating Parkinson’s disease (Click here for that post).
The ARCUS inhalation technology. Source: ParkinsonsLife
Basically, the inhaler contains capsules of L-dopa, which are designed to break open so that the powder can escape. By sucking on the inhaler (see image below), the open capsule starts spinning, releasing the levodopa into the air and subsequently into the lungs. The lungs allow for quicker access to the blood system and thus, the L-dopa can get to the brain faster. This approach will be particularly useful for people with Parkinson’s disease who have trouble swallowing pills/tablets – a common issue.
The Phase 3, double-blind, placebo-controlled clinical trial evaluated the efficacy and safety of CVT-301 when compared with a placebo in people with Parkinson’s disease who experience motor fluctuations (OFF periods). There were a total of 339 study participants, who were randomised and received either CVT-301 or placebo. Participants self-administered the treatment (up to five times daily) for 12 weeks.
The results were determined by assessment of motor score, as measured by the unified Parkinson’s disease rating scale III (UPDRS III) which measures Parkinson’s motor impairment. The primary endpoint of the study was the amount of change in UPDRS motor score at Week 12 at 30 minutes post-treatment. The change in score for CVT-301 was -9.83 compared to -5.91 for placebo (p=0.009). A negative score indicates an improvement in overall motor ability, suggesting that CVT-301 significantly improved motor score.
The company will next release 12-month data from these studies in the next few months, and then plans to file a New Drug Application (NDA) with the Food and Drug Administration (FDA) in the United States by the middle of the year and file a Marketing Authorization Application (MAA) in Europe by the end of 2017. This timeline will depend on some long-term safety studies – the amount of L-dopa used in these inhalers is very high and the company needs to be sure that this is not having any adverse effects.
All going well we will see the L-dopa inhaler reaching the clinic soon.
The banner for today’s post was sourced from the Huffington Post
Donating blood helps to save lives. And an awful lot of blood is needed on a daily basis: In the England alone, over 6,000 blood donations are required every day to treat patients.
There has been concerns over the years about what can be transmitted via blood donation (from donor to recipient). The good news is that we now know that Parkinson’s disease is not.
Today’s post looks at recent research investigating this issue and discusses the implications of the findings.
Blood transfusions save lifes. Source: New York Times
The average adult human carries approx. 10 pints (about 6 litres) of blood in his body. So much blood, that we actually have an excess – we can survive with a little less. And this allows us to donate blood to blood banks on a regular basis (approx. every 8 weeks). Roughly 1 pint can be given during each blood donation and our bodies will have no trouble replacing it all.
These donations can be used in blood transfusions, replacing blood that has been lost via accident or during surgical procedures. It may surprise you that blood transfusion (from human to human) has been practised for some time. The very first blood transfusion was performed by an obstetrician named Dr. James Blundell in the late 1820’s.
Dr. James Blundell. Source: Wikpedia
The exact date of that first procedure is the subject of debate, but Blundell wrote up his experience in the journal Lancet in 1829:
Blundell’s article in the journal Lancet. Source: Wikipedia
Since that time, blood transfusions have gradually become an everyday occurrence at hospitals all over the world. And as we suggested above a lot of blood is used on a daily basis, keeping people alive. Determining whether each donation of blood is safe to use is obviously a critical step in this process, and all donated blood is tested for HIV, hepatitis B and C, syphilis and other infectious diseases before it is released to hospitals. But for a long time there has been a lingering concern that not everything is being detected and filtered out.
In fact there has been a serious concern that some neurodegenerative conditions like Alzheimer’s and Parkinson’s disease may be transmissible. If these diseases are being caused by ‘prion-like behaviour’ from the particular proteins involved with these conditions (eg. beta amyloid and alpha synuclein, respectively), then there is a very real possibility that such rogue proteins could be transferred via blood transfusions.
This was a concern (note the past tense) until July of this year when this research report was published (with a rather mis-leading title):
Title: Transmission of neurodegenerative disorders through blood transfusion. A cohort study
Authors: Edgren G, Hjalgrim H, Rostgaard K, Lambert P, Wikman A, Norda R, Titlestad KE, Erikstrup C, Ullum H, Melbye M, Busch MP, Nyrén O.
Journal: Ann Intern Med. 2016 Sep 6;165(5):316-24.
The researchers in this study took all of the data from the enormous nationwide registers of blood transfusions in Sweden and Denmark – collectively almost 1.5 million people have received transfusions in these two countries between 1968 and 2012 – and compared the medical records of the recipients to those of the donors (you have to love the Scandinavians for the medical databases!). Approximately 3% of the recipients received a blood transfusion from a donor who was diagnosed with one of the neurodegenerative diseases included in this study (Alzheimer’s, Parkinson’s and Motor neurone disease (or Amyotrophic lateral sclerosis – ALS). There was absolutely no evidence of transmission of any of these diseases.
For the statistic lovers amongst you, the hazard ratio for dementia in recipients of blood from donors with dementia versus recipients of blood from healthy donors was 1.04 (95% CI, 0.99 to 1.09). Estimates for individual diseases, Alzheimer disease and Parkinson disease were 0.99 (CI, 0.85 to 1.15) and 0.94 (CI, 0.78 to 1.14), respectively.
These statistics mean that if Parkinson’s disease is being transmitted via a blood transfusion, it is an extremely rare event.
So what does this mean for our understanding of Parkinson’s disease?
Well, we already know that you can’t catch Parkinson’s disease from your spouse (Click here to read more on this) and there is a lot of other evidence to suggest that Parkinson’s disease is not contagious (Click here to read more on this). So this is one less thing for carers, family members and friends to worry about.
But if Parkinson’s disease is not caused by some contagious agent, this knowledge has major implications for our understanding of the disease. Previous lab-based research has pointed toward a ‘Prion’-like nature to alpha synuclein (the protein most associated with Parkinson’s disease. Prions being small infectious agents made up entirely of protein material, that can lead to disease that is similar to viral infection. And researchers actually found that if you inject specific types of alpha synuclein into the muscles of mice, those animals would start to develop cell loss in the brain (Click here to read more about this).
If Parkinson’s disease is a ‘prion’ condition, then we have to ask one important question: why isn’t it being transmitted via blood transfusion? Alpha synuclein is certainly found in the blood of people with Parkinson’s disease.
It could be that an infectious agent initiated the condition many years ago and it has very slowly been developing (similar to chronic infections resulting from Hepatitis – click here to read more on this).
Research like we have reviewed today may result in a serious re-think of our theory of Parkinson’s disease.
The banner for today’s post was sourced from CampusCluj
Last week there was a press release from La Trobe University in Melbourne, Australia regarding the development of a new blood test for Parkinson’s disease. The announcement is a little bit odd as the results of the study are still being peer-reviewed (press announcements usually come after the publication of results). But the Parkinson’s community is excited by the idea of new diagnostic aids, especially those that can maybe tell us something new about the disease.
In this post, we will review what we know at present, and we will follow up this post once the results are eventually published.
As we have previously written, the diagnosis of Parkinson’s is rather difficult, with a 10-15% error rate becoming apparent when brains are analysed at the postmortem stage. Thus any new diagnostic tools/tests that can aid in this effort would be greatly appreciated.
A group at La Trobe University in Melbourne have been studying the blood of people with neurodegenerative conditions, and have now announced that they may have a blood test for Parkinson’s disease.
The La Trobe University team: (left to right) Professor Paul Fisher, Dr Sarah Annesley and Dr Danuta Loesch-Mdzewska. Source: La trobe
So what do we know thus far?
The test has been conducted on blood taken from a total of 38 people (29 people with Parkinson’s disease and 9 in a control group). Professor Paul Fisher – one of the lead scientists in the study – has reported that the tests have proven ‘very reliable’.
What does the test measure?
The test is apparently looking at the mitochondria in the blood cells.
And what are mitochondria?
A mitochondrion (singular) is a small structure inside a cell that is responsible for respiration and energy production. It is one of the powerhouses of the cell. Cells have lots of mitochondria (plural) because cells need lots of energy. But when the mitochondria start failing, the cell dies. As the mitochondria fails, they send out toxic chemical signals that tell the cell to begin shutting down.
A schematic of a mitochondria, and where they are inside a cell. Source: Shmoop
The researchers at La Trobe found in their blood tests that there was no damage to the mitochondria of patients with Parkinson’s disease. That in itself is an interesting observation, but what they found next has larger implications:
“Based on the current literature we were expecting reduced oxygen consumption in the mitochondria, which leads to a buildup of toxic byproducts, but what we saw was the exact opposite,” Prof Fisher was quoted as saying. “We were able to show the mitochondria were perfectly normal but were working four times as hard, which also leads to increased production of poisonous byproducts to occur.”
A test that can measure these ‘hyperactive’ mitochondria is very useful as it can both identify people with Parkinson’s disease, but it may also help us to better understand the condition. Prof Fisher and his colleagues, in addition to taking the test forward, are also trying to understand the underlying mechanisms of the ‘hyperactive mitochondria’ – what is causing them to become the way they are.
What is going to happen now?
The scientists at La Trobe would like to repeat and expand on the results (after they are published), and the Michael J Fox foundation and Shake It Up Australia have given La Trobe University more than $640,000 to further develop the research. The plan is to now test 100 subjects – 70 people with Parkinson’s disease and a control group of 30. Prof Fisher is hoping that a test may be available for the clinic in five years time.
What about other neurodegenerative conditions?
So here’s the catch with the information provided thus far – the researchers have not had the funding to test whether this hyperactivity in the mitochondria is occurring exclusively in people with Parkinson’s. That is to say, they haven’t tested whether the effect is also present in people with other neurodegenerative diseases, such as Alzheimer’s, Huntington’s, or ALS. And this is where a little bit of the excitement comes out of the announcement.
But even if the hyperactivity in the mitochondria is shared between certain neurodegenerative diseases, a test highlighting the effect would still be very useful, especially if it can aid us in early detection of these conditions.
As we said above, we will be following this story closely and will report back here as and when information becomes available.