Researchers at Johns Hopkins found in mice with a rodent form of multiple sclerosis (MS), vitamin D appears to block damage-causing immune cells from migrating to the central nervous system, offering a potential explanation for why the so-called "sunshine vitamin" may prevent or ease symptoms of the neurodegenerative disease.
The quest to understand the role of the nutrient began with the observation that the disease is more prevalent in regions of the world farthest from the equator where there is less sunshine, the main natural source of vitamin D.
"With this research, we learned vitamin D might be working not by altering the function of damaging immune cells but by preventing their journey into the brain," study leader Anne R. Gocke, Ph.D., an assistant professor of neurology at the Johns Hopkins University School of Medicine, said.
For their study, Gocke and her colleagues simultaneously gave mice the rodent form of MS and a high dose of vitamin D. They found that this protected the mice from showing symptoms of the disease. The researchers still found a large number of T cells in the bloodstream of the mice, but very few in their brains and spinal cords.
Gocke said vitamin D may slow a process of making a sticky substance that allows the T cells to grab onto blood vessel walls, which allows the T cells to remain in circulation and keeps them from migrating to the brain.
Gocke says an important thing to consider with vitamin D treatment is that its immunosuppressive effects appear to be fleeting. Once vitamin D is withdrawn, MS-like flare-ups in mice can occur very quickly.
The upside is that if a patient developed an infection and the body appeared too immune-compromised to fight it, discontinuing the vitamin D temporarily could quickly allow the immune system to recover and attack the infection, she says.
The study is published in the National Academy of Sciences.
--ANI (Posted on 10-12-2013)