American scientists have discovered that antihistamine treatment could help repair certain brain damage caused by multiple sclerosis.
- Multiple sclerosis is an autoimmune disease that affects the central nervous system.
- Multiple sclerosis patients lose the protective insulation that surrounds nerve fibers, myelin.
- Researchers have found that antihistamine treatment could restore myelin damage.
Multiple sclerosis is an autoimmune disease that affects the central nervous system. Lesions resulting from dysfunction of the immune system lead to motor, sensory, cognitive, visual and even sphincter deficiencies. Current treatments make it possible to reduce inflammatory flare-ups and improve patients’ quality of life, but they do not prevent the progression of the pathology.
Treatment for multiple sclerosis: repairing myelin
In a study published in the journal PNAS In 2023, researchers at the Neuroscience Institute at the University of California in San Francisco (United States) observed that clemastine, an over-the-counter antihistamine, could repair certain lesions caused by multiple sclerosis.
Multiple sclerosis patients lose myelin, the protective insulation that surrounds nerve fibers. In the brain, water trapped between thin layers of myelin cannot move as easily as water floating between brain cells. Because of this property of myelin, American scientists developed an imaging technique to examine myelin levels before and after taking clemastine. They called it the myelin water fraction, which characterizes the ratio of myelin water to the total amount of water in the brain.
Clemastine repairs myelin
For their study, the researchers recruited patients with multiple sclerosis. They divided them into two groups: the first received clemastine during the first three months of the study and the second group only received the drug between the third and fifth months.
The scientists then used the water fraction of myelin as a biomarker. They noticed that myelin water increased in the first group given the drug and that this increase continued after the treatment stopped. As for the second group, the myelin water fraction showed a reduction in myelin water in the first part of the study when the volunteers were on placebo, before experiencing an increase when the patients were benefited from clemastine.
For the authors of the study, this increase in myelin water after treatment is indicative of myelin repair in patients with multiple sclerosis. “This is the first example of brain repair documented by magnetic resonance imaging (MRI) for a chronic neurological disease”, said Dr. Ari Green, lead author of the study and medical director of the Multiple Sclerosis and Neuroinflammation Center at the University of California, San Francisco. Before adding: “Clemastine may only be partially effective at the doses we can use (…) This drug can be sedative, which can be particularly undesirable in patients with multiple sclerosis. We hope that better drugs will be developed, but clemastine turned out to be the tool to show that remyelination is possible.”
