Multiple sclerosis: Vitamin D supplementation may block the action of autoimmune lymphocytes

Multiple sclerosis: autoimmune lymphocytes blocked thanks to vitamin D supplements. Here's how

Vitamin D can block brain inflammation, typical of multiple sclerosis, due to the action of T lymphocytes on neurons. It in fact, in laboratory mice, appears to interfere with the migration of immune cells from the lymph nodes to the central nervous system. 

New studies may therefore shed light on the role of vitamin D supplementation in the prevention and treatment of the disease. This is the finding of a study conducted by researchers at the Johns Hopkins University School of Medicine in Baltimore, USA, and published in the journal PNAS.

Vitamin D: an important regulator of the immune system

The positive effects of vitamin D on the symptoms of the disease emerged in the past few years when it was observed that multiple sclerosis had a high prevalence in countries far from the equator and thus the sun. 

Vitamin D, in fact, besides being contained in foods, can be synthesized in the human body from a precursor found in the skin, 7-dehydrocholesterol, by the action of sunlight. The vitamin exists in several forms, the most common being D2 of plant origin, and D3 of animal origin. Both play a key role in 'absorption of calcium and phosphorus in the intestines, regulate bone growth, development, and mineralization, and modulate the functioning of the immune system. 

Precisely because of this last aspect, the vitamin brings numerous benefits in the case of various diseases including multiple sclerosis. This is an autoimmune disease, which involves the myelin sheath-that is, the lamellar layer, which surrounds the axons of neurons, formed by membranes of specialized cells called Schwan cells. The myelin's job is to isolate nerves and, more importantly, to speed up the transmission of the nerve impulse necessary for movement, speech and a variety of other functions. 

As the disease develops, T helper lymphocytes destroy myelin, causing the typical symptoms of sclerosis, such as blurred vision, weakness and motor difficulties.

Supplementation blocks lymphocyte travel to the nervous system

During the study, the researchers, led by Anne Groke, administered the murine form of the disease and high doses of vitamin D as the bioactive metabolite 25(OH)D (25-hydroxycholecalciferol) to laboratory mice, and observed that the animals, however, did not show symptoms of the disease. When they analyzed T Helper lymphocytes, they were found to be activated and in high concentrations in the bloodstream but well away from the spinal cord and brain. 

The researchers therefore hypothesized that the vitamin does not directly interfere with brain inflammation, but acts by blocking the travel, to the nervous system, of autoimmune cells by keeping them away from the target sites of damage.

Rapid and reversible action

Researchers also claim that the immunosuppressive effect of vitamin D supplementation explodes very quickly and just as quickly disappears If therefore a patient is affected by an infection, discontinuation of vitamin D administration can quickly bring back the activation of the immune system, which is necessary to fight the ongoing infection. The importance of this is readily apparent when one considers that the current immunosuppressive drugs used to treat the disease, need at least 6-12 weeks to be totally eliminated from the body. 

It now remains to be clarified through further studies whether the effect and mechanisms described in laboratory guinea pigs are the same in humans. To stay up to date with the latest news from Omega-3 scientific research, subscribe to our newsletter.

Source: Grishkan IV, Fairchild AN, Calabresi PA, Gocke AR. "1,25-Dihydroxyvitamin D3 selectively and reversibly impairs T helper-cell CNS localization. ".Proc Natl Acad Sci U S A. 2013 Dec 24;110(52):21101-6