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Host – Dan Keller
Hello, and welcome to Episode Nineteen of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.
This week’s podcast features the second half of an interview with Dr. Samuel Ludwin. This time Dr. Ludwin and I discuss the implications of treating multiple sclerosis subtypes. But to begin, here is a brief summary of some of the latest developments on the MS Discovery Forum at msdiscovery.org.
This week we reported some good news: a large case-controlled study showed that there is no causal link between vaccines and multiple sclerosis. However, the study came with the caveat that there is some increased risk for developing MS in younger patients who receive vaccines. This increased risk is likely due to the vaccines triggering a pre-existing asymptomatic condition, the researchers said. The study, which was published in the journal JAMA Neurology, was most concerned with the role that vaccines for hepatitis B and human papillomavirus play in the long-term risk for developing MS.
We also reported on a new iPad app that will allow clinicians and MS patients to track their disease course. The app, called Bioscreen, is currently in beta-testing at the University of California, San Francisco. The developers, including Pierre-Antoine Gourraud who is on MSDF’s scientific advisory board, assert that Bioscreen has the potential to be a powerful tool for researchers, clinicians, and patients. At the core of the app is a dataset of around 600 patients who have been participating in a data collection survey for the past 10 years. Physicians can compare their patient’s disease course with other confirmed MS cases and use that information to influence their recommendations. The researchers also believe that patients’ ability to visualize their own disease in this way will improve adherence to medical recommendations and ultimately strengthen the bond between patient and physician.
Every week we publish at least one “Research Roundup” where we curate stories from around the web related to multiple sclerosis. Recently we published roundups about advances in spinal cord injury treatment, the recipe for selling the perfect bogus drug, and the report of a rare brain infection in a patient taking dimethyl fumarate, trade name Tecfidera. To view Research Roundups, go to the “News Briefs” section of the “News and Future Directions” tab at msdiscovery.org. Look for the blue Research Roundup logo and stay up-to-date with all the latest MS news.
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Now to the interview with Dr. Samuel Ludwin, a neuropathologist who is currently a visiting scientist at the Montreal Neurological Institute. Last week we aired an interview with Dr. Ludwin in which he discussed remyelination therapies. This week he speaks with MSDF about MS subtypes.
Interviewer – Dan Keller
Welcome, Dr. Ludwin. Let’s talk about some of the subgroups of multiple sclerosis, as has been proposed by Professor Hans Lassmann, and you wrote an editorial some time ago about it. First of all, can you tell me what subgroups he identified and what progress there has been made since then?
Interviewee – Samuel Ludwin
This is a very groundbreaking paper, very controversial, and over the years many people who have followed this particular pattern, others who’ve not been able to reproduce it and believe that the conclusions are not valid. However, what Claudia Lucchinetti and Hans Lassmann showed in a mammoth first-time examination of very acute lesions; they had access to a particularly unique group of specimens that are from both the Mayo Clinic and other areas, where very early lesions were examined. And in looking at this, they looked at patterns of tissue breakdown and the mechanisms of tissue breakdown, and essentially came up with four different categories. The two most important ones are very important to discuss because in the one, the features were very, very consistent with the kind of immune injury that one finds in experimental allergic encephalomyelitis where we know the damage has been caused by the injection of the antigen with a subsequent immune reaction to that antigen. And the other main group was one where there appeared to be a primary damage of some sort to the oligodendrocyte and then a subsequent immune reaction.
Now this is important for a couple of reasons, and the first is that there is a big debate going on in the multiple sclerosis literature or research as to whether the disease starts from the outside peripheral activation of immune cells and then homes in on the brain because they are cross-antigens or cross-antibodies or cross-cells, or whether the process actually starts with damage to something in the brain which subsequently sets off the – and this is called the “inside-out” or “outside-in” controversy at the same time. What this might mean, according to the way they have done the study – which was a very good one – was they suggested that there might be multiple mechanisms towards the end result of damage to oligodendrocytes and myelin, and subsequently the physical appearance of multiple sclerosis lesions.
Other people have challenged this and suggested that maybe it is a question of timing, and the mechanism is the same in all patients, but we’re looking at a different kind of progression and timing. And that controversy is still being discussed, as is the inside-out, outside-in phenomenon. But when you look at some of the things that might be causing these inside-out or their type 3 pattern where the primary damage could be in the oligodendrocyte, there are many reasons that the mechanism could be due to either stroke-like causes such as a lack of oxygen or blood flow that damages the oligodendrocyte, possibly certain infections that may target the oligodendrocyte. And we know that there are many mouse models where you can target oligodendrocytes with certain viruses. And those overlap very significantly with mechanisms of tissue damage in other diseases.
So it is a very important paper because it has set people thinking about multiple mechanisms. The fallout from this is that, in fact, when you have different mechanisms of causing disease, there are potentially different ways of treating it. And if you have a primary immune-based phenomenon from the outside, antiinflammatories as are given on disease-modifying therapies are perhaps the way to go, whereas if you’ve got something that is damaging it from the inside and some other cause, we need to elucidate what that cause is and go straight for that particular cause. In addition, what we are trying to find out is whether we can predict what sort of pattern has caused the disease, either with imaging or with biomarkers, and be able to do this without biopsies and other things so that patients can be treated accordingly. It’s an advance on perhaps what we might call personalized medicine in multiple sclerosis.
MSDF
Are there imaging or clinical correlates of these different types of processes? You’re not going to do a biopsy on most people.
Dr. Ludwin
No, there isn’t. But in fact, there are some therapeutic differences. For instance, in the type 2 pattern, which is the autoimmune pattern or the outside-in pattern, these patients respond very well to plasmapheresis where one is removing the offending gammaglobulin. And patients with the type 3, which is the main oligodendrocyte-based pattern of the disease, they don’t respond to that well. And that’s perhaps the best clinical differentiation that we know at the moment that helps us. A lot of the data is not clear. They based a lot of the data on the fact that they felt that every patient had a uniform pattern in the lesions. Other people have questioned this and found that there might be a multitude of different kind of patterns in the same patient, and therefore it supported modifications of the same inherent cause.
MSDF
Does the efficacy of plasmapheresis correlate with the presence of oligoclonal bands in the CSF, or that’s not a correlation?
Dr. Ludwin
There doesn’t seem to be a correlation, leastwise I know. Certainly plasmapheresis where we know that there is antibody, such as in neuromyelitis optica is more effective as a treatment early for diseases where we know that there is circulating antibody, but patients will have oligoclonal banding, I think, in both patterns.
MSDF
You’d alluded to damage to the oligodendrocyte in one of these forms as the primary dysfunction or lesion. Does that imply that something is being exposed, an antigen that might be reacted to, or how is that leading to damage?
Dr. Ludwin
Absolutely, that if you get damage to a tissue, various proteins are being broken down and antigenic epitopes are being exposed, which then are transported back to the peripheral lymphoid tissue for reactions to take place. I mean, there are counter-arguments to this. One can ask why, with a lot of trauma injury, a lot of stroke injury which is far more common than MS, why you don’t get a secondary immune response to that, even though we know many people with the genetic makeup makes them susceptible to MS or exist in the normal population, and almost certainly some of them have strokes. So there are questions on both sides and arguments. And we know from other experiments that you can induce circulating antigens with tissue destruction of any cause, and potentially these are circulating to be able to produce reactive antibodies in the periphery.
MSDF
I think Lassmann showed that even in healthy people you can find CNS antigens in the cervical draining lymph nodes, which raises the same question you just brought up; why do some people have a reaction and some not?
Dr. Ludwin
Absolutely, and there are now all sorts of theories coming out of the genetics that there are multiple genes, each having a small effect, but in totality may be adding up to a genetic defect that will allow some of these circulating cells to suddenly start having an effect.
MSDF
Now it seems, in terms of thinking of personalized medicine, so much of it is empiric – what works works, and you try something else if it doesn’t. Is there a possibility of any harm from these treatments to people for whom it doesn’t work? Do you have to be very concerned about also first not do harm, especially considering you can’t tell the difference among these types from the start?
Dr. Ludwin
Yeah, I think that it’s too early to apply personalized medicine to patients in this particular area in the different types. If you’re looking at personalized medicine that, you know, we treat patients as individuals, or we should, because a lot of the therapy is based on empiric choice and anecdotal experience sometimes with the clinician, and there’s no absolute algorithm that everybody uses to treat a patient. So in that sense, we already do practice it. But you’re quite right, a lot of that is anecdotal or empirical rather than mechanistic.
The do no harm is a very interesting point also, because you mustn’t forget that basically multiple sclerosis is an inflammatory disease, and very frequently we tend to look at inflammation as being something that’s bad. But the reason the body mounts an inflammatory infiltrate is usually to cure something or to clean up something that is attacking it from the outside. So in any kind of these interferences, we have to choose a very find balance between stopping an inflammatory infiltrate or reaction that may be doing a lot of good for the patient, while preventing it from its worst excesses.
And here, empiricism comes in quite well at the moment; we know which of these drugs that we give are more likely to give side effects, we know more about side effects than we do about potential for not allowing growth. We will stop a particular cytokine or block a particular protein in its action, but I think we should always be aware that the protein, if it’s a normal one and not abnormal protein, may be there for a reason and the patients will do worse if they don’t have this mess cleaned up, so to speak.
MSDF
We’re also finding today that we’re almost living in a proinflammatory environment; it has repercussions in heart disease, dental disease, MS, fat is proinflammatory. So do all these things add to the risk in MS if there’s other inflammatory processes going on?
Dr. Ludwin
Well, it’s not only the inflammatory processes that’s going on, it’s the things that are causing them. As you’re right, we are now discovering that things like salt, fast foods, the changes in the microbiota all tend to make us more proinflammatory. And certainly in experimental animals and now some human studies, it has been shown that experimental immune disease is worsened by a high salt intake which leads to increased salt in the tissues, as well as being prevented by some of these diseases. If you change the gut microbiota in many of these diseases from normal commensals into something that may be pathogenic, you will set off inflammatory autoimmune disease. It’s been shown very beautifully in ulcerative colitis and Crohn’s disease, and the same thing is now being looked at very strongly in multiple sclerosis, so certainly a proinflammatory environment.
On the other hand, it should be remembered that there’s certain kind of infections that produce a reaction that may very well be protective, and there’s some evidence that some of the parasites produce a factor and we believe it could be related to a particular type of protective T-cell that will then allow for patients to become resistant to multiple sclerosis. And there’s some very good data from South America that populations who’ve been exposed to parasites and have them are actually more resistant to multiple sclerosis, because the parasite has induced a protective antiinflammatory molecule in the cell as well. So it’s a very complex balance and we’re gradually discovering more and more about where this balance lies.
MSDF
Might the prevalence of parasites account, at least in part, for the geographic distribution of MS?
Dr. Ludwin
Well, parasites are just one part of it. There is a very strong feeling, and it comes back to also the gut microbiota – but it’s more than just gut microbiota; it’s environment microbiota – that this has a major role. And for many years, it wasn’t just parasites. People in the Third World had a much lower incidence of multiple sclerosis, and this could have been also from genetic reasons or from susceptibility. But it was not just for multiple sclerosis. All autoimmune disease was much lower in frequency in these populations, and the theory was that most of the people who grew up in developing countries were exposed to large numbers of bacteria and they developed robust immune systems, normal-functioning immune systems that could help them deal with it. And the theory is that in developed countries, the over-usage of antibiotics has aborted normal immune responses, and so in response to that autoantibodies are created and we are suffering the consequence of living too clean a life. And so I think if you look at that argument, it’s not just multiple sclerosis, it really has been mooted for the inflammatory bowel disease, juvenile diabetes, rheumatoid arthritis, and other immune diseases as well.
MSDF
Thank you, this has been very good.
Dr. Ludwin
Pleasure.
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Thank you for listening to Episode Nineteen of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Robert Finn. Msdiscovery.org is part of the non-profit Accelerated Cure Project for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is vice president of scientific operations.
Msdiscovery.org aims to focus attention on what is known and not yet known about the causes of MS and related conditions, their pathological mechanisms, and potential ways to intervene. By communicating this information in a way that builds bridges among different disciplines, we hope to open new routes toward significant clinical advances.
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