Disabling conditions result when the myelin sheathing of nerves is sufficiently degraded, such as via a malfunctioning immune system attacking the body's own tissues, as is the case for multiple sclerosis. All of us suffer loss of myelin with aging to some degree however, due to damage and dysfunction in the oligodendrocyte cell populations responsible for maintaining myelin. There is evidence for this specific issue to contribute to age-related cognitive decline. Thus treatments that focus on boosting remyelination are of general interest: if safe, they should probably be applied to every older person, not just those with conditions such as multiple sclerosis.
Glial cells play several key roles in the central nervous system, including supplying oxygen to neurons and forming myelin - the protective, fatty substance that protects the nerve cells' axons. In multiple sclerosis (MS), glial cells called oligodendrocytes are attacked by the immune system, causing a breakdown of myelin that disrupts the signals between nerve cells and results in a loss of motor and sensory functions.
Researchers are developing a method for regenerating myelin with progenitor glial cells. When they transplanted the cells into mouse models of MS, the cells transformed into new oligodendrocytes and restored myelin. Now, a company that was spun out last year, Oscine Therapeutics, is preparing the cell therapy for human clinical trials in MS and other glial diseases.
In the mouse study, researchers showed that after transplantation, the human glial progenitor cells migrated to damaged areas of the brain. After they created new oligodendrocytes, myelation was restored, as was motor function. Much of the regenerative medicine research in MS is focused on restoring myelin, and several different approaches are under investigation. Last year, researchers reported that when they implanted stem cells with the surface protein CD34 into mouse models of MS, the cells grew into myelin-forming glial cells. Other experimental approaches to regenerating myelin include using microRNAs and reprogrammed skin cells.