Multiple sclerosis is an inflammatory autoimmune disease whereby the patient’s immune system destroys the protective sheath (called myelin) that envelops and protects the nerves. As a result, the flow of information in the brain and spinal cord is interrupted. Ultimately, the actual nerve cells are affected and die. Patients with multiple sclerosis show a variety of symptoms involving the nervous system, including spasms, difficulty walking, bladder and bowel problems and fatigue.
There are two concurrent components to any successful therapeutic approach to multiple sclerosis. One is to prevent damage to the central nervous system by interfering with inflammation and/or the immune system’s attack on the nerves; the other is to repair the existing damage.
Stem cells are potentially useful in both components. Clinical trials in which patients have received transplants of blood stem cells from their own bone marrow or blood have shown some benefits: a proportion of patients did not progress in the disease; others showed no improvement and others regressed. In all trials, participants went through intensive treatments to suppress their immune systems before being given the transplants.
Research using animal models has shown that it is possible to re-myelinate damaged nerves, by transplanting very young ensheathing cells (so-called precursor cells), made from embryonic stem cellsi or adult neural (brain) stem cells. However, other animal studies show that the improvements seen after injecting neural stem cells are due mainly to effects of the cells on suppressing inflammation and may, therefore, not be long-lasting. Furthermore, the inflammatory environment could destroy the transplanted ensheathing cells, which would make it necessary to treat patients with immunosupressant or anti-inflammatory drugs.
Scientists know that in the early stages of multiple sclerosis, the existing myelinating cells are able to offer some spontaneous remyelination. An important area of research is focused on finding ways to enhance remyelination from these cells.
Relevant links:
The European Multiple Sclerosis Platform
The Multiple Sclerosis Society
Multiple Sclerosis Trust
The National Insitute of Neurological Disorders and Stroke