A new mouse study by University of Florida Health researchers shows that multiple sclerosis can be inhibited or even reversed by using a gene therapy that stops the immune response caused by the disease in its tracks.

What is multiple sclerosis?

Multiple sclerosis (MS) is an autoimmune disease, affects around 2.3 million people worldwide and is the most common neurological disease in young adults. The average life expectancy for people with MS is around 6 to 7 years lower than the norm[1].

This lifelong condition begins when the immune system attacks the myelin sheath surrounding nerve fibres, making them misfire, which leads to a wide variety of symptoms, including visual problems, arm or leg movement difficulty, and issues with sensation, speech or balance.

MS can potentially be cured by clearing out the entire adult immune system and waiting for it to re-establish itself again. Removing the dysfunctional immune cells that cause the autoimmune condition can halt the disease, though replacing the entire immune system is a risky procedure. This is an extreme approach, but as we do not know exactly where the problem begins, it is one of the few ways to deal with it.







A new approach to MS

The new study saw researchers combining a brain-protein gene with an existing MS medication in mice[2]. The mice which had MS were treated with this combination, and a near-complete remission of the disease was observed.

Using a harmless virus known as an adeno-associated virus, the team was able to deliver a gene responsible for a brain protein into the livers of the mice. The virus released its payload, causing the production of regulatory T Cells, which then suppressed the dysfunctional immune cells responsible for causing MS.

The researchers also combined this therapy with rapamycin — a drug used to prevent organ transplant rejection — to further increase its effectiveness. The combination was even better at allowing the proliferation of helpful regulatory T cells while, at the same time, preventing an increase of problematic effector T cells.

Of the mouse groups that were given rapamycin and the gene therapy, 71 percent and 80 percent, respectively, went into near-complete remission after experiencing hind-limb paralysis. This shows that the combination can be effective at stopping rapidly progressing paralysis caused by MS.







Using other animal models of MS, the researchers are now conducting further clinical studies to increase their understanding of the disease and its mechanisms and, ultimately, to refine the technique. Dr. Hoffman, the lead researcher, is extremely optimistic that the gene therapy can be effective in humans.

Conclusion

While the connection to autoimmune diseases, such as MS and aging, may not be immediately clear, what we learn from this could potentially translate. The aging immune system suffers from an increasing level of dysfunction, which could potentially be eliminated by removing all immune cells, removing the cells causing problems, or even just altering the behaviour of the problematic cells.

Completely removing the immune system is the least elegant approach to dealing with age-related immune dysfunction and autoimmune diseases; however, given the gap in current knowledge, it is the easier option. It is, however, not without considerable risk.

Targeting the problem cells for removal and altering their behaviour are the more refined approaches, and this is the direction in which researchers are moving. Once the holes in our understanding are filled, we will be able to precisely deal with these cells, and, ultimately, this is the elegant solution.







This area of research, while focused on autoimmune diseases, has the potential to be applied to aging, so we will be keeping a close watch on progress in this area.

Literature

[1] Sadovnick, A. D., Ebers, G. C., Wilson, R. W., & Paty, D. W. (1992). Life expectancy in patients attending multiple sclerosis clinics. Neurology, 42(5), 991-991.

[2] Keeler, G. D., Kumar, S., Palaschak, B., Silverberg, E. L., Markusic, D. M., Jones, N. T., & Hoffman, B. E. (2017). Gene Therapy-Induced Antigen-Specific Tregs Inhibit Neuro-inflammation and Reverse Disease in a Mouse Model of Multiple Sclerosis. Molecular Therapy.