Turn skin cells into nerve cells to repair the damage caused by multiple sclerosis and some leukodystrophies, is the challenge taken up by the ICM scientists. These extremely encouraging results would enable the consideration of a cell therapy from the affected patients’ own cells.
In myelin disorders such as multiple sclerosis, the destruction of the myelin protective coating that surrounds the axons (extensions of neurons and threads to nerve impulses), impairs the transfer of information to nerve tissue and can lead to motor, sensory, balance, and visual disorders… Although a capacity for the renewal of the myelin exists, this process is still ineffective in the SEP.
Find ways to make myelin in order to restore damaged nerve connections is one of the major focuses of Anne Baron Van Evercooren (Inserm/ICM) and her team. Scientists have generated nerve cells from skin cells (fibroblasts). These skin cells taken from the adult are initially reprogrammed in order to give pluripotent stem cells (cells capable of giving any type of cell, or IPS) and then neural stem cells at the origin of neurons and glial cells. A particular type of glial cells, called oligodendrocyte is responsible for the production of myelin.
In an experimental model of multiple sclerosis, scientists have showed that these cells reprogrammed from fibroblasts differentiate into mature oligodendrocytes and migrate to demyelinated areas of the spinal cord. Once there, they remyelinate the damaged axons, restore the nodes of Ranvier (which are essential to the transmission of nerve signals) and increase the conduction velocity of nerve messages, as effectively as cells derived from the central nervous system.
Skin cells could therefore be used as an autologous (within an individual), and customised source of nerve cells aimed at producing myelin. This major breakthrough in the field of myelin disorders such as multiple sclerosis opens up very promising opportunities to lead to a functional recovery in patients.