New Discovery about Myelin Could Impact Multiple Sclerosis
Researchers have made a new discovery about myelin that could have a significant impact on how multiple sclerosis is viewed and treated. The finding concerns cells called oligodendrocytes, which have a crucial role in nervous system functioning.
Lab animals are traditionally used in research aimed at understanding the intricacies of human health and disease. Now a study of the human brain seems to turn current theories involving myelin and oligodendrocytes in mice and rats versus people on their ear.
Myelin is the protective sheathing on nerve fibers that facilitates the rapid transmission of nerve impulses. Oligodendrocytes are the building blocks of myelin in the central nervous system--the brain and spinal cord.
Up to now, research has shown that when the nerve cells in mice and rats need more myelin, oligodendrocytes are replaced. Therefore, investigators assumed the same was true in humans.
At Karolinska Institutet, a team of international experts have discovered that mice and men are not equal when it comes to myelin and oligodendrocytes. Based on the evaluation of the brains of 55 deceased individuals ranging in age from infancy to 92 years, researchers report the following:
- The majority of oligodendrocytes are immature at birth
- Oligodendrocytes mature rapidly until an individual is around age 5 years. Most of the cells have peaked by this age
- Carbon dating of the cells established that humans replace oligodendrocytes at a low rate of only 1 in 300 per year, a discovery that surprised the researchers
What the study findings mean
Previous work has shown that the body is capable of repairing myelin, but the process is slow. Scientists are also working on ways to fix myelin in MS patients, including research that involves the culturing of human placenta cells. In addition, there is at least one drug in the pipeline that focuses on reversing damage to myelin.
Experts have also shown that it is possible to increase myelin production and that more myelin is produced in the brain when people learn something new. This demonstrates the ability of the brain to respond and adapt to new situations, an ability referred to as brain plasticity.
The work by the Karolinska Institutet team has shown that the human brain and the mouse and rat brain do not work the same way regarding myelin manufacturing, as once thought. Thus the plasticity of the brain differs between mice and men.
This is good news, as noted by Jonas Frisen, one of the study’s authors and Professor of Stem Cell Research at the Department of Cell and Molecular Biology, because “We now have new basic knowledge to build upon.” Hopefully this new knowledge will lead to better ways to prevent, manage, and treat multiple sclerosis.