Seasonal paradox – why MS symptoms may improve as days get shorter

A new approach regarding Melatonin for MS Symptom Seasonal Variations

Harvard-affiliated researchers from the Ann Romney Center for Neurologic Diseases at BWH wanted to understand why symptoms of multiple sclerosis change with the seasons, improving as the days get shorter. They have found an explanation that could lead to a deeper understanding of the disease and more targeted treatment options for patients.

Multiple sclerosis is a disease that affects the central nervous system, including the brain, optic nerves, and spinal cord.

Why do symptoms of multiple sclerosis (MS) seem to get better in the winter and worse in the summer?

By looking first broadly at possible environmental factors and then deeply at preclinical models of MS, the research team found that melatonin, a hormone involved in regulating a person’s sleep-wake cycle may influence MS disease activity. The team carried out some tests and found that during the fall and winter, the group of 139 relapsing remitting MS patients they studied experienced a significant improvement in symptoms, a phenomenon that has been observed in previous studies. The team then explored a variety of environmental factors that have been proposed as possibly linked to MS symptoms, including vitamin D levels, UV incidence, and upper respiratory tract infections.

The factor that was consistently associated with severity of MS symptoms was melatonin. Melatonin levels are known to correlate with the durations of days. During the longer days of the spring and summer, levels are lower and during the shorter days of the fall and winter, levels are higher. Based on this observation, the team tested this lead in the lab, studying the role that melatonin may play on a cellular level.

Using both a mouse model and human cells, they investigated the effects of melatonin on certain types of cells known to play a role in the immune response that leads to MS symptoms.

The team found that melatonin affected the roles of two kinds of cells that are important in MS disease progression, pathogenic T cells, which directly attack and destroy tissue, and regulatory T cells, which are supposed to keep pathogenic T cells in check. They found that melatonin has a protective effect .It dampens the immune response and helps keep the bad guys or pathogenic T cells at bay. Although melatonin is available over the counter, it has significant drawbacks, including causing unwanted drowsiness.

The researchers caution that this work does not mean that MS patients should start taking supplements of melatonin, an imperfect drug.

Instead, this new approach, which takes its lead from environmental observations, can be seen as a first step toward better and more targeted therapies.

The team is currently working to establish a pilot clinical trial to study the effects of targeting melatonin signaling in MS patients and identify additional mechanisms of action.

 

For more information please visit:

www.harvard.edu

 

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