Multiple sclerosis is a chronic neurological disease that affects the brain and spinal cord. In multiple sclerosis, an immune reaction breaks down the covering around neuronal axons, myelin. Depending on where in the brain or spinal cord this inflammation occurs, patients with multiple sclerosis may experience weakness, a lack of sensation, double vision, difficulty walking, difficulty with balance, problems with urination, dizziness, and/or pain. Over time, patients with multiple sclerosis require assistive devices such as canes or wheelchairs to get around, and some ultimately become bedridden.
Multiple sclerosis can be divided into 4 types:
Clinically isolated syndrome – The first episode of MS; about two-thirds of people with a clinically isolated syndrome of MS will go on to have one of the other types listed below
Relapsing-remitting – Patients have symptoms for a time, which resolve, but then eventually return
Secondary progressive – After some cycles of flare-ups and remissions, the disease is present all the time; some patients with relapsing-remitting disease develop secondary progressive MS
Primary progressive – Once symptoms start, they do not resolve but instead get progressively worse
Fortunately, there are some treatments that can change the course of multiple sclerosis. There are several disease-modifying agents available for people with relapsing-remitting disease and a few for progressive multiple sclerosis. These drugs can reduce the rate at which symptoms get worse or extend the length of time between flare-ups. Unfortunately, not everyone can tolerate these drugs, and, in others, the drugs are not very effective. None of these drugs is a cure for multiple sclerosis.
Researchers have turned to mesenchymal stem cells as a possible treatment for multiple sclerosis. These cells have the ability to regulate the immune system and support the nervous system. There have been so many clinical trials of stem cells in multiple sclerosis that researchers can now perform a meta-analysis on them. A meta-analysis is a special study in which all trials on a particular topic are combined and analyzed, i.e., a study of studies.
In their recent meta-analysis, Dr. Zhou and co-authors identified 9 clinical studies using mesenchymal stem cells to treat multiple sclerosis. They found that the rate of disease progression with stem cell treatment was 16% at 6 months and 35% at 1 year. This is a faster rate of decline than disease-modifying treatment, but better than no treatment at all. Importantly, the MS patients treated with stem cells had much more severe disease than average—it was a group for whom disease-modifying treatment had failed. From this perspective, stem cell treatment for MS was a great success.
Most patients had no evidence of disease activity at 6 months (72%) and 1 year (62%) after autologous mesenchymal stem cell treatment. This a substantial duration of time to be disease-free.
The authors noted that stem cells transplanted via the intrathecal route (i.e. directly in the cerebrospinal fluid) resulted in a slower progression of disability.
Taken together, these results are encouraging. The authors also concluded that mesenchymal stem cell treatment was safe. More work with larger patient groups are needed, but this is an exciting avenue of research.
Reference: Zhou, Y., et al. (2019). Autologous Mesenchymal Stem Cell Transplantation in Multiple Sclerosis: A Meta-Analysis. Stem Cells International. 2019, Volume 2019 |Article ID 8536785.