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Hello, and welcome to Episode Thirty of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.
This week’s podcast features an interview with Dr. Seema Tiwari-Woodruff about estrogen in animal models of MS. But to begin, here’s a brief summary of some of the latest developments on the MS Discovery Forum at msdiscovery.org.
Last week, we reported on the results of another clinical trial for hematopoietic stem cell transplantation in relapsing-remitting MS. Compared to the “halt-MS” trial, which we reported on in January, this study used a less aggressive conditioning approach. Patients involved in the study demonstrated improvement in EDSS scores, and eighty percent of them were relapse-free at four years. The results raised important questions about how to prep MS patients for the transplant. Visit our “News and Future Directions” section to read the full story.
A recent study published in the Multiple Sclerosis Journal demonstrated a potential new way to monitor lesion repair using standard MRI techniques. Clinical trials usually look for new lesions in brain scans to monitor drug efficacy. Lead author, Daniel Reich, told MSDF it’s more important than ever to be able to visualize changes in tissue since drug development is shifting towards neuroprotection and repair.
We’re also pleased to announce that Daniel Reich is one of two new members of our Scientific Advisory Board. Dr. Reich is the director of the Translational Neuroradiology Unit in the National Institute of Neurological Disorders and Stroke, part of NIH. Our other new board member is Deborah Backus, an expert on rehabilitation who is Director of Multiple Sclerosis Research at the Shepherd Center in Atlanta, Georgia. Read their full bios in our “Who We Are” section under the “About Us” tab.
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Now to the interview. Dr. Tiwari-Woodruff is an associate professor of biomedical sciences at the University of California, Riverside. She met with MSDF editor-in-chief, Bob Finn, to talk about her research on estrogen and multiple sclerosis.
Interviewer – Robert Finn
Dr. Tiwari-Woodruff, welcome.
Interviewee – Seema Tiwari-Woodruff
Thank you.
MSDF
So what is the connection between estrogen and MS?
Dr. Tiwari-Woodruff
It’s an interesting connection between estrogen and MS, because estrogen is actually a part of life in a way that our brains require it, our bodies require it at every moment of our life, I should say. Many years ago it was found that relapsing-remitting patients had less relapses when they were pregnant, and the causes of that was potentially estrogens – high levels of them – or progesterone or vitamin D. Many researchers went ahead and looked at those high levels of pregnancy estrogens called estriol and found that high levels of estriol were the reason why these women patients had lower levels of MS symptoms.
So eventually down the line, estrogens were parsed out of which estrogen was better. And it turns out that one type of estrogen, which is the estrogen of the alpha, is more immunomodulatory – it actually suppresses the immune response – and that is probably what makes MS symptoms better versus estrogens of the beta ligand was known not to have that much immunomodulatory effect; instead, it was actually directly neuroprotective. So estrogens of the alpha and beta both seem to have an effect on various cell types which are involved in multiple sclerosis.
MSDF
So if estrogen seems to be protective in pregnant women with MS, why not just use estrogen, or an analog like estriol or estradiol, as a treatment?
Dr. Tiwari-Woodruff
That’s a very good question. And, first, these therapies were thought that we were going to use those first, and a lot of clinical trials were going through with that. But what happens with high levels of estrogen is there are two things which are important to know. One is they have a feminizing effect, and the second one is they have a preponderance for causing uterine cancer or breast cancer. So you don’t want to stimulate those two types of cancer. So high levels of estrogen could be dangerous in that aspect. So that is why we don’t want to use that as potential therapy.
MSDF
So you’ve done a lot of work with a specific estrogen receptor agonist called indazole chloride. First, tell me how you came upon this compound.
Dr. Tiwari-Woodruff
So estrogens of the beta ligands are not just being looked at for multiple sclerosis, they were being looked at as a potential therapeutic for menopause – hot flashes included – rheumatoid arthritis, and other impairments like prostate cancer, etc. So there were quite a few chemists who were coming up with various different types of estrogen receptor beta ligands. So while I was doing my work with mouse models of MS in generic estrogen receptor beta ligand, which was the DPN – diarylpropionitrile – a study came out which was actually on indazole chloride which was developed by a chemist, John Katzenellenbogen; he’s done a lot of work on developing these molecules. And this particular compound showed that it decreased activation of astrocytes and microglia; this was published in Cell a few years back. And we met at a meeting, John Katzenellenbogen and myself – we were giving a talk at the same time in a meeting in Stockholm – and we decided to talk to each other. And he said, “Your research is very intriguing on estrogen receptor beta ligand, would you like to try this out?” And that’s how I got my hands on the indazole chloride. And we did some preliminary studies and showed good results. Then we decided to embark on a full-fledged study which was published in PNAS.
MSDF
So you used indazole chloride in two different mouse models of MS, and you used it both prophylactically and in mice that are already showing symptoms. What did you find?
Dr. Tiwari-Woodruff
So prophylactically when you use a compound, you are actually trying to see if you can inhibit the symptoms which are going to come up when you induce a disease, and that is all good. But when you are talking about patients who come to see the doctor, they’re always coming in with symptoms, so they already have the disease ongoing. So the second paradigm where you give the drug when the disease symptoms are already there is closer to what humans are going to be able to see. So the nice thing about indazole chloride was that, prophylactically, definitely it made the mice better, but therapeutically also; they were able to decrease the disease symptoms by nearly 50%.
MSDF
What is the significance of the fact that it seems to work on two different mouse models of MS?
Dr. Tiwari-Woodruff
So when you’re looking at a drug especially in a disease like multiple sclerosis which has two major components – one is inflammatory component and another one is a neurodegenerative component – if you can show that this drug is working in one way or both ways would be very useful for developing better drugs or better treatments. So what we did was when we treated the mice with indazole chloride, in one mouse model which is the experimental autoimmune encephalomyelitis which contains both the inflammatory and the neurodegenerative component, we saw a decrease in the disease symptoms. But we couldn’t tell if the indazole chloride was working in the inflammatory component or the neurodegeneration component, because it showed effect on both.
So we went to a second mouse model which is the toxic cuprizone diet model which doesn’t have a primary inflammatory component. The disease starts with oligodendrocytes, the cells which make the myelin. They die when you feed this diet to the mice, so they have massive demyelination in regions of the brain. When we gave the drug during the remyelination phase, we found that indazole chloride was able to remyelinate the axons better when the drug was present versus when it was absent. So this actually showed us that indazole chloride has two arms to it. One, it inhibits the inflammatory component and the second, it inhibits the neurodegenerative component independent of the inflammatory component.
MSDF
Is it also sort of confirmatory? The EAE is not a perfect model of MS and neither is the cuprizone mouse model, but does it make you feel better that these two completely different models are showing similar effects?
Dr. Tiwari-Woodruff
Absolutely, you really hit the point where… We are always looking for the best model for multiple sclerosis, but because the disease is so complex no one model can be said that it’s 100% mimicking multiple sclerosis. So for us to see that demyelination which occurs both in EAE and the cuprizone model was improved – we actually saw remyelination in both models – really gave us hope that this drug could be directly acting on oligodendrocytes which are forming the myelin, which is the cause of major mode of dysfunction in multiple sclerosis.
MSDF
So does indazole chloride help these mice a little bit, or does it help them a lot?
Dr. Tiwari-Woodruff
So that’s a very good question. Similar to what you might see in the patient population, in the mouse model of MS, especially in the EAE model, the disease is not consistent. So the lesions which appear in the brain of EAE animals are very diverse, unlike the cuprizone model where the demyelination is very consistent. So when you’re looking at these mice, especially in the EAE cohort, if the animal is really, really sick, you actually see the disease symptoms go down just a little bit. But if the animals were sick to the middle level, they actually showed a bigger difference, they showed better recovery. And we hypothesize that the axons which have been injured to the point of no return, if the axons have been demyelinated and injured, it doesn’t matter now when you give them therapeutic drugs, these are not going to improve. So there are certain number of axons in the brain which drop out and we don’t see recovery in those. But said that, overall we still saw a significant increase with indazole chloride treatment in both models.
MSDF
Have you done histology?
Dr. Tiwari-Woodruff
Yes. We’ve done histology, we’ve done electron microscopy. And we do one more thing my lab is very good at, we do electrophysiology. Because one of the things we always think is when you look at remyelination you can see myelin coming up, but is the myelin functional? If the axons can conduct faster or better, then you know that the myelin which has covered the axons is functional. So we do all three. And we also include behavioral testing. So one of the tests we included which a lot of people use is a Rota rod; it’s a motor test to show that the mice can stay on the Rota rod much longer after treatment with indazole versus just the vehicle.
MSDF
Do you see any side effects?
Dr. Tiwari-Woodruff
So that’s interesting. We did not see any side effects in these mice. Agreed, we treated them up to 60 days, we haven’t treated them longer than that, plus we were giving them at a 5 mg/kg/day concentration. So we didn’t see any kind of toxicity. But said that, we still need to do those studies in a thorough way before we can safely say that they had no side effects.
MSDF
So what’s next in the development of indazole chloride as a potential MS treatment?
Dr. Tiwari-Woodruff
So indazole chloride is a good target. And while these studies were going on last year, John Katzenellenbogen and myself, we were talking about how are we going to proceed with this because we were seeing really good results; this is even before I published the paper. And he said what would you like to do? And one of the things we said was is it possible to make better analogs of this compound which are going to be more specific, could be used in a lower concentration and may have a better therapeutic outcome?
So he came up with four analogs which he has sent to me, and we did some preliminary studies to see if they were toxic to cells in culture, because that’s the first thing you do. And they have no toxicity in cells, they actually have shown to behave well with proliferation – depreciation of the cell – and we haven’t seen more cell death or less cell death with them. So we are very excited about that. So coming next month, we are actually going to start treatment of EAE animals, and once that goes through the goal is to do toxicity studies on the two best compounds and see if we can find a company so we can have a backing on these drugs for potential human trials. It’s a couple years from now, at least – it could be even more – but we are actually moving in that direction.
MSDF
Dr. David Baker in a commentary on his multiple sclerosis research blog seemed less than enthusiastic about indazole chloride. He suggested that many compounds seem to work similarly in mouse models. How do you respond to that criticism?
Dr. Tiwari-Woodruff
So Dr. Baker has a very good point on saying that there could be many compounds which are good in EAE but they fizzle out and they don’t go up to clinical trial. I disagree on one point where it comes to indazole chloride, because we have precedence of estrogens showing good therapeutic indication in humans; there were clinical trials done in UCLA where they showed that there was improvement with estriol treatment. And estriol does target both ER-alpha and ER-beta – ER-beta a little more than ER-alpha – so I’m very confident that what we are seeing with estrogen receptor beta is not a fluke. And because it’s a steroid and a small molecule, it does not seem to have a lot of toxicity involved which could be somewhat which is brand new. So we’ll see. I hope Dr. Baker’s wrong and we do manage to get this drug to human patients and we see therapeutic efficacy in them.
MSDF
Dr. Baker also said that a critical experiment had not yet been done. And let me quote from his blog post. He said, “The development of demyelination should be allowed to occur after this damage has abated, then punitive remyelinating drugs should be given.” How do you respond to that?
Dr. Tiwari-Woodruff
Very good point made by Dr. Baker, but I have actually addressed those in the PNAS paper. We part off particularly this aspect of the disease. So the prophylactic treatment was before the disease started; that is what he’s mentioning in the blog. The second part is what is important where EAE disease was induced, and after peak disease had occurred we gave the drug, indazole chloride. At the peak disease, we actually see increased inflammation, but alongside with that we see demyelination and axon degeneration. So the damage has already started. The drug treatment after that is what caused the disease to get better. We saw increased conduction, we saw increased remyelination, and less axon damage.
Similar to that, we also did the experiment in cuprizone. The treatment paradigm was as such: We actually had nine week of demyelination ongoing in the cuprizone model, which is very chronic; it’s chronically ongoing where you have quite a bit of damage of the axons and you have acute demyelination. During the remyelination phases where we gave the drug either to one group and vehicle to the other group, what we saw was that the drug treatment, indazole chloride, actually increased remyelination and decreased axon damage. So I think Dr. Baker was trying to make a point on we haven’t done the right experiment, but I think we have done the right experiment. And further research with indazole chloride will let us know if this is a good drug or not.
MSDF
Dr. Tiwari-Woodruff, is there anything you’d like to add?
Dr. Tiwari-Woodruff
I would like to add one more thing. We have actually looked at indazole chloride in optic neuritis – EAE-induced optic neuritis – and we are going to be publishing a paper fairly soon showing that in optic neuritis we see less inflammation in the retina and increased remyelination in the optic nerve. So I’m very confident that it’s not just a phenomenology in one part of the brain which we picked last time – it was the corpus callosum – that we see increased remyelination and decreased damage caused by EAE with treatment of indazole chloride.
MSDF
Well, thank you very much.
Dr. Tiwari-Woodruff
Thank you.
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Thank you for listening to Episode Thirty 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 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.
We’re interested in your opinions. Please join the discussion on one of our online forums or send comments, criticisms, and suggestions to editor@msdiscovery.org.
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