Melatonin May Play a Role in Seasonal MS Relapses

Melatonin improves symptoms in mice and reduces levels of specific T cells

THURSDAY, Sept. 10, 2015 (HealthDay News) -- Higher levels of melatonin are linked to a lower incidence of multiple sclerosis (MS) relapses during the darker months of fall and winter, new research suggests. The study is published in the Sept. 10 issue of Cell.

Francisco Quintana, Ph.D., a researcher from Brigham and Women's Hospital in Boston and associate professor of neurology at Harvard Medical School, and colleagues studied a group of 139 patients with relapsing-remitting MS. The authors found that participants experienced a 32 percent reduction in relapses during fall and winter compared to spring and summer.

The researchers also gave daily injections of melatonin to mice with an autoimmune disease mimicking several key features of MS. The melatonin improved symptoms in the mice and reduced levels of specific T cells (Th17 cells), restoring a healthy balance of T cells in the brain, spinal cord, and organs involved in immune response, the researchers said.

The new research suggests a stronger basis for melatonin's role in controlling seasonal MS flare-ups compared to vitamin D, Quintana told HealthDay. Vitamin D is thought to help cut the frequency of MS flare-ups in spring and summer -- when natural melatonin levels are lower -- due to its anti-inflammatory effects. But "it looks that melatonin has the better association," Quintana added. "The two of them [melatonin and vitamin D] contribute to control disease activity, but specifically with regards to seasonal changes, melatonin plays a stronger role than vitamin D in MS."

The study was supported in part by grants from pharmaceutical companies.

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