Vitamin D could play a role in who gets multiple sclerosis.
Vitamin D3 insufficiency increases multiple sclerosis (MS) susceptibility in a gene and sex-dependent manner, a mouse study suggests.
The study with that finding, “Sex-Specific Gene-by-Vitamin D Interactions Regulate Susceptibility to Central Nervous System Autoimmunity,” by researchers at the University of Vermont, was published in the journal Frontiers in Immunology.
MS is a progressive, neurodegenerative, autoimmune disease. Previous studies have estimated that genetic factors account for a significant portion of MS risk, ranging from 20 to 30 percent, while the remaining risk factors are either environmental or a combination of gene-environment interactions.
There are several environmental risk factors thought to be associated with MS susceptibility, including Epstein-Barr virus (EBV) infection, low sunlight/ultraviolet (UV) radiation exposure, vitamin D3 deficiency, and smoking.
Vitamin D3 (VitD) insufficiency is one of the most-studied environmental MS risk factors. Interestingly, while previous studies reported a strong correlation between low VitD levels and higher MS risk in caucasian populations, this was not the case for blacks and hispanics, suggesting the involvement of a genetic component.
Indeed, several MS susceptibility genes are thought to be regulated by VitD, but the underlying mechanisms involved in the process are still unknown.
These effects also have been studied in animal models of MS. Dietary supplementation with VitD in younger mice and rat models of MS prevented these animals from developing experimental autoimmune encephalomyelitis (EAE), a condition that mimics the key pathological features of MS in humans.
Curiously, in these animals, VitD effects were observed only in females and seemed to require the presence of estrogen, suggesting the involvement of a sex-dependent mechanism.
However, ongoing clinical trials testing dietary VitD supplementation as a preventive or therapeutic strategy for MS in humans have failed, so far, to show a consistent benefit.
Now, researchers tested whether VitD levels can regulate the central nervous system autoimmune response in a gene and sex-dependent manner.
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