Melatonin, the same hormone that helps people fall asleep by regulating the body’s internal clock, may be helpful in treating multiple sclerosis, according to a study from Raúl Carrea Institute for Neurological Research in Buenos Aires. Neurologists Dr. Mauricio Farez and Dr. Francisco Quintana noticed that when melatonin levels are highest during the year (fall and winter), multiple sclerosis patients experience fewer flare-ups. In summer, when levels are lower, patients are highly affected by flare-ups.
“Our research explains something that wasn’t known before in terms of how multiple sclerosis is modulated by the environment,” said Dr. Quintana in a news release. Dr. Farez and Dr. Quintana’s research team conducted a study that looked at seasonal effects of melatonin on multiple sclerosis by following 139 patients over the course of a year. In the winter, relapses were found to be reduced by 32%.
To make a link between multiple sclerosis and melatonin, researchers tracked the levels of 6-SM, a component of melatonin. Levels of 6-SM dipped when flare-ups became more frequent. The study, “Melatonin Contributes to the Seasonality of Multiple Sclerosis Relapses,” was published in the journal Cell.
Investigating further, the research team applied melatonin to an experimental mice model of multiple sclerosis and looked at the response of T-cells, which are important mediators of flare-ups in multiple sclerosis. Upon melatonin treatment, the number of protective T-cells in the mice increased significantly, and harmful cell populations decreased.
The exact mechanism of how melatonin acts on T-cells to protect further damage in multiple sclerosis has yet to be clarified. Scientists are still researching how protective T-cells shield myelin from further destruction by the immune system.
Neurologist Dr. Lawrence Steinman at Stanford University cautions that research efforts in addition to those that focus on T-cells are necessary to continue understanding multiple sclerosis. “This group is enthusiastic about the role of [rogue T-cells], and so am I, but it’s only part of the story,” he said. Additionally, the research conducted by Dr. Farez and Dr. Quintana focused on only a subset of multiple sclerosis patients–those living in Buenos Aires, where the amount of seasonal daylight is different from other parts of the world.
The team further cautions that multiple sclerosis patients should not attempt to self-treat by using over-the-counter sleep aids (which contain melatonin) to reduce flare-ups. “We don’t want patients to see the study and misinterpret our results,” said Dr. Farez. “It’s a neat study and great data, but we still need to do a lot of work.” Doses, side effects, and overall treatment safety and efficacy need to be explored further before melatonin is recommended in multiple sclerosis therapy regimens.