insomniacs and world travelers use both melatonin a hormone that regulates the body's internal clock to help them fall asleep and get some extra shuteye. Now, a new study shows that the "sleep hormone" may also provide relief to patients with multiple sclerosis (MS), a debilitating neurological disorder that can quickly morph remission in attacks that the last days, months, even years.
MS is a rare disease in which the immune own body cells attack neurons by eating away their protective layer, fat. This layer, the "myelin sheath" -insulates the portion of the neuron that transmits signals, such as flexible plastic protects the telephone cables. In patients with multiple sclerosis, the damaged sheath off the cell-cell communication, knocking out the vision, balance and muscle coordination, while altering the thinking and memory. The cause of MS is still unknown, and scientists suspect that environmental factors such as low vitamin D, obesity and viral infections could contribute.
Another environmental factor could be changes in the seasons. Mauricio Farez, a neurologist at the Institute Raúl Carrea for Neurological Research in Buenos Aires, and colleagues suspected as much when they noticed that fewer multiple sclerosis relapses occurred in the fall and winter time of year that melatonin production is at its peak.
melatonin levels depend on sun exposure, so that seasonal changes cause hormone fluctuate; less sunlight in fall and winter increases melatonin, while more sun in spring and summer decreases.
To test the "seasonal" effect of melatonin on MS patients, researchers followed 139 MS patients for a year, monitoring the rates and levels of a small molecule in melatonin relapse called SM-6. They saw that during the fall and winter, relapse rates of patients was 32% lower than in the rest of the year, when melatonin levels naturally plunge.
Think of the immune system probably played a key role, scientists hypothesized that the increase in melatonin has led to increased advocacy organizations called regulatory T cells, which work by secreting proteins protective that prevent rogue immune cells in check. At the same time, the active melatonin a protein that blocks the production of harmful T cells. The researchers then confirmed their hypothesis in mice: When animals dosed with melatonin, rodents increased production of protective T cells and reduced their levels of harmful cells. The team has seen similar effects on human cells in the laboratory, it makes online account today Cell . "Our research explains something that has not been experienced before in terms of how MS is modulated by the environment," says co-author Francisco Quintana, a neurologist at Ann Romney Centre for disease neurological at Brigham and Women's hospital in Boston.
Although the results are a step in the right direction, the link between melatonin and the immune system still lacks some important details. Researchers have yet to identify, for example, how helper T cells protect the myelin sheath misguided immune attack. Farez said he and his colleagues plan to explore this process in the future.
But other researchers caution against too absorbed in a single mechanism of an extremely complicated disease. "This group is enthusiastic about the role of [rogue cell] Th17, and me too, but it is only part of the story," said Lawrence Steinman, a neurologist at Stanford University in Palo Alto, California who specializes in MS.
Monitoring of clinical research should target a larger population, more inclusive, experts say. The current study included only patients in Buenos Aires. Farez said a diversified geographic sample is important to ensure melatonin has the same effects on patients in locations with different amounts of the light of day season.
But the main concern of the team has not to do with the experimental setup. It must give way to training on the effects of the publication of this research. Melatonin is widely available as a helper over-the-counter sleep, and they fear that some MS patients can use the hormone as an additional treatment. "We do not want patients to see the study and misinterpret our results," says Farez. "It's a neat and big data study, but we still need to do much work."
Learn more about melatonin and MS remission on Science Signaling site.
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