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 is able to block the brain inflammation typical of multiple sclerosis caused by the action of T lymphocytes on neurons. Indeed, in laboratory mice, it appears to interfere with the migration of immune cells from lymph nodes to the central nervous system.
New studies may shed light on the role of vitamin D supplementation in the prevention and treatment of the disease. This emerges from a study conducted by researchers at 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 disease symptoms have emerged in recent years when it was observed that multiple sclerosis has a high prevalence in countries far from the equator and therefore from the sun.
Vitamin D, in fact, besides being contained in foods, can be synthesized in the human body from a precursor present in the skin, 7-dehydrocholesterol, under 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 fundamental role in the absorption of calcium and phosphorus at the intestinal level, regulate the growth, development and mineralization of bones, and modulate the functioning of the immune system.
Precisely for this last aspect, vitamin D brings numerous benefits in case of various diseases including multiple sclerosis. This is an autoimmune disease involving the myelin sheath, that is, the lamellar layer surrounding the axons of neurons, formed by membranes of specialized cells called Schwann cells. The role of myelin is to insulate the nerves and, above all, speed up the transmission of the nerve impulse necessary for movement, speech, and various other functions.
With the onset of the disease, T helper lymphocytes destroy the myelin causing typical symptoms of sclerosis, such as blurred vision, weakness, and motor difficulties.
Supplementation blocks the journey of lymphocytes to the nervous system
During the study, researchers led by Anne Groke administered the murine form of the disease to laboratory mice and high doses of vitamin D, as the bioactive metabolite 25(OH)D (25-hydroxycholecalciferol), and observed that the animals did not show symptoms of the disease. Analyzing the T helper lymphocytes, they found them activated and in high concentrations in the bloodstream but far from the spinal cord and brain.
The researchers therefore hypothesized that vitamin D does not directly interfere with brain inflammation, but acts by blocking the travel of autoimmune cells towards the nervous system, keeping them away from the sites targeted by the damage.
A rapid and reversible action
The researchers also state that the immunosuppressive effect of vitamin D supplementation arises very quickly and disappears just as rapidly. Therefore, if a patient contracts an infection, stopping vitamin D administration can quickly restore immune system activation, necessary to fight the ongoing infection. The importance of this is clear, considering that current immunosuppressive drugs used to treat the disease need at least 6-12 weeks to be completely eliminated from the body.
It remains to be clarified through further studies whether the effect and mechanisms described in laboratory animals are the same in humans. To stay updated on the latest scientific research on Omega-3, 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
