According to Inserm, with approximately 2,500 new cases diagnosed each year in France, multiple sclerosis is the leading cause of severe non-traumatic disability in young adults. In France, it affects over 100,000 people according to the Ministry of Solidarity and Health. It is an autoimmune disease that affects the central nervous system (ie the brain and spinal cord): cells of the immune system, dormant, turn on their own camp and attack the body. Myelin that surrounds and protects our nerve fibers. These well-known “plaques”, caused by lesions, prevent nerve fibers from properly transmitting messages sent by the brain to the rest of the body, and vice versa. Depending on their location, the results can be motor, sensory, cognitive or visual.

To date, there is no cure for this disease. There are many treatments that can improve the quality of life of patients, but despite ongoing research, nothing is curative. Researchers at the University of Geneva (UNIGE) in Switzerland have tackled the problem by trying to devise a strategy to prevent immune cells in affected organisms from breaking down the myelin in nerve fibers.

life history theory

First proposed in the 1950s, the “theory of life history” or “of life stories” is part of the field of evolutionary biology, and is integrated into the action of natural selection. It seeks to explain the evolution of living organisms to guarantee their reproductive success and, therefore, the survival of their species in general.

Depending on the environment in which an organism is located, its energy resources will not necessarily be allocated to the same things because it will not have the same preferences for survival: for example, under optimal conditions an animal will lose its energy. devoted to growth and reproduction. . Whereas in contrast, in an unfavorable environment, the maintenance of the organism would be preferred (eg by saving as much energy as possible, or by establishing a defense mechanism). Various “life stories”, hence.

The UNIGE team used this principle to tackle the problem of multiple sclerosis: since it is an autoimmune disease, would it be possible to reduce it by depriving the system of immunity from its energy resources?

redistribute energy to ease symptoms

According to their results, published in the journal cell metabolism, the answer is yes ! In the rats they studied, suffering from the counterpart of multiple sclerosis, exposing the body to cold (about 10 °C) for two weeks made it possible to force redistribution of its energy resources. Instead of dedicating them to the immune system, the mice helped maintain their body temperature by increasing their metabolism. Study co-author Doron Merkler explains that “The animals had no difficulty maintaining their body temperature at a normal level, but, alone, the symptoms of locomotor disorders decreased dramatically, from the inability to walk on their hind legs to mild paralysis of their legs. . Ask.” Fewer resources, less immune system activity, fewer lesions, fewer symptoms: CQFD for UNIGE researchers.

They will now look at the potential clinical applications of their discovery. The work’s lead author, Mirko Trzekovsky, specifies that “While the concept of prioritizing the thermogenic response over the immune response is clearly protective against autoimmunity, it should be noted that cold exposure increases susceptibility to certain infections.” Thus, their results “May be useful for understanding not only neuroinflammation, but also other infectious or immune-mediated diseases, which will need to be further researched.”