Supplementing the body’s own thyroid hormone during a critical phase of multiple sclerosis may help repair the damage caused by the disease, according to new research.

The study showed that treating rats with a multiple sclerosis-like disease with thyroid hormone helped protect them from further nerve damage and sped up the repair of already damaged nerve fibers.

Researchers say if further studies confirm these results, thyroid hormone may be offered in conjunction with other multiple sclerosis treatments.

Thyroid Hormone May Ease MS

Multiple sclerosis is a disease that affects the nervous system and causes nerve fibers to become “unsheathed.” Myelin sheaths insulate the nerve fibers in the brain and spinal cord, and when these protective sheaths become damaged through what is thought to be immune system mediated inflammation, the results are a loss of movement and function.

In the new study, published in the Nov. 16 issue of the Proceedings of the National Academy of Sciences, researchers tested the effects of thyroid hormone treatment in rats with a multiple sclerosis-like disease. The disease in the rats was a model of “relapse remitting” multiple sclerosis, the most common form of the disease. It is characterized by flare-ups, followed by periods of recovery.

The study showed that in the rats with multiple sclerosis-like disease, treatment with thyroid hormone during a phase of early nerve damage resulted in protection of the myelin sheath in nerves. In addition, treatment with thyroid hormone accelerated the development of precursor cells into cells which can form new myelin sheaths in already damaged nerve fibers.

Researchers say the treatment appears to work by stimulating the development of cells known as OPCs. In multiple sclerosis, these cells fail to further develop into myelin-making cells.

But the study showed that when rats were treated with thyroid hormone at a point when a large number of these precursor cells were available, the treatment triggered these cells into action.

Researchers say the results suggest that thyroid hormone treatment may work as a safe and noninvasive addition to improve the effectiveness of other existing multiple sclerosis treatments.

By Jennifer Warner, reviewed by Brunilda Nazario, MD

SOURCE: Fernandez, M. Proceedings of the National Academy of Sciences, Nov. 16, 2004; vol 101: pp 16363-16368.