Certain Environmental Conditions May Trigger Demyelination, Onset of MS

Certain environmental conditions may trigger the structural changes found in myelin sheaths during the onset of multiple sclerosis (MS), according to a new study.

The study, published in the Proceedings of the National Academy of Sciences, examines the effect of environmental conditions, such as salinity and temperature, on myelin sheaths.

MS, a chronic inflammatory autoimmune disease, leads to the destruction of myelin sheaths, which are the protective layers surrounding the axons. Although the etiology of the disease is still unknown, previous studies have suggested that changes in the structure of myelin sheaths can contribute to the development of MS. Additionally, prior research has suggested that environmental factors may play a role in onset of the disease.

For the study, the researchers used X-ray scattering and cryogenic transmission electron microscopy (cryoTEM) to track and measure the myelin sheaths in healthy and diseased animal models. They observed that changes in salinity and temperature caused the myelin membrane to make a transition between a healthy stack of lamellas to diseased inverted hexagonal phase, according to the study.

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When affected by various environmental conditions, the myelin sheaths undergo structural transitions at the molecular level, which can create structural instabilities that allow the immune system to attack neurons, according to the researchers. “Due to the proximity of cytoplasmic myelin membrane to structural phase transition, minor alterations in the local environment conditions can have devastating results,” they wrote in the study.

Additionally, the study authors found that these phase transitions have different transition points that depend on the lipid’s compositions and are ion specific.

“Current therapeutic approaches have focused on the autoimmune response without identifying the culprit,” lead study author Roy Beck, professor at Tel Aviv University’s School of Physics and Astronomy, said in a press release. “We have found that under certain environmental conditions, such as elevated salinity and temperature, myelin sheaths protecting neurons undergo structural transition consistent with pathological myelin structures in multiple sclerosis.”

The researchers concluded that local environmental conditions are critical for myelin function and may play a role in causing MS, signaling opportunities for early diagnosis and avoiding the onset of demyelination.

References

Shaharabani R, Ram-On M, Talmon Y, et al. Pathological transitions in myelin membranes driven by environmental and multiple sclerosis conditions. PNAS. 2018.

https://doi.org/10.1073/pnas.1804275115

Environmental Factors May Trigger Onset of Multiple Sclerosis [news release]. Tel Aviv University’s website. https://www.aftau.org/weblog-medicine--health?&storyid4704=2410&ncs4704=3. Accessed October 16, 2018.