Slow down multiple sclerosis
Scientists have learned how to stop multiple sclerosis
Scientists have discovered a molecule whose blocking slows down the development of multiple sclerosis, a dangerous autoimmune disease that leads to disability. The results of the study are published in the journal Science Translational Medicine (Michel et al., Activated leukocyte cell adhesion molecule regulates B lymphocyte migration across central nervous system barriers).
Multiple sclerosis is a chronic autoimmune disease in which the myelin sheath of nerve fibers of the brain and spinal cord is affected. The disease in its initial stage manifests itself in the form of symptoms such as fatigue, impaired coordination, vision problems, cognitive impairment and mood changes. The progressive course can lead to partial paralysis and disability.
In a healthy person, the brain is protected from the ingress of toxins and microorganisms circulating in the blood through the hemato-encephalic barrier (BBB) between the circulatory and central nervous systems. The same physiological mechanism prevents the cells of the immune system – lymphocytes - from entering the nervous tissue.
However, in people with multiple sclerosis, the BBB becomes permeable. A large number of lymphocytes enter the brain and disrupt its tissues, destroying the myelin sheath, which protects neurons and ensures the transmission of nerve impulses. As a result, numerous foci of chronic inflammatory demyelination arise – plaques of multiple sclerosis, composed of anti-myelin antibodies synthesized by B-lymphocytes.
Existing anti-B-cell drugs reduce the activity of lymphocytes and, thus, inhibit the development of the disease.
Canadian scientists from the Research Center of the University Hospital of Montreal, with the assistance of their American colleagues from the University of Pennsylvania, found that the ALCAM molecule (activated leukocyte cell adhesion molecule) accelerates the development of multiple sclerosis.
"In our study, we show for the first time that the ALCAM molecule expressed by B cells controls their entry into the brain through blood vessels. This allows lymphocytes to migrate to the other side of the hemato-encephalic barrier in mice and humans, – the words of the head of the study Alexander Prat (Alexandre Prat) are quoted in the press release of the hospital. "By blocking this molecule in mice, we were able to reduce the influx of B cells into their brains and, as a result, slow down the progression of the disease."
Vessels of the brain affected by multiple sclerosis. On the left – before the suppression of the ALCAM molecule, on the right – after the suppression. Purple colored B-lymphocytes. A drawing from an article by Michel et al.
Scientists conducted experiments on live mice and on human cells in the laboratory. The results showed that in the B cells of people with multiple sclerosis, the ALCAM molecule is expressed at higher levels, and blocking ALCAM in mice stopped the progression of the disease.
The authors believe that their discovery could lead to the creation of anti-ALCAM drugs and the development of new treatments for multiple sclerosis.
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