Picture of Healthy Axons

Myelin is the fatty covering that surrounds axons in the spinal cord and brain. It is this protective coating that permits electrical impulses to be conducted, much like the insulation surrounding an electrical cord. Myelin can be damaged or lost either through traumatic injury (such as a spinal cord injury) or by disease (such as multiple sclerosis). When myelin is destroyed or damaged, the ability of the nerves to conduct electrical impulses to and from the brain is disrupted, much like a wire whose insulation has been stripped.

Picture of Demyelinated Axons

Demyelinated axons lose the ability to conduct impulses and this can eventually lead to the degeneration of nerve fibers. Acorda has several therapies in development that act to counter the affects of demyelination axons. Fampridine SR permits the axon to transmit impulses again, even in a demyelinated state, resulting in increased neurological function.

Picture of Partially Remyelinated Axons

The cells that make myelin, called “oligodendrocytes” have a strictly limited capacity to repair areas of damage in the adult nervous system. Acorda is working to develop treatments using two molecules that increase this capacity for remyelination, Glial Growth Factor-2, or GGF2, and the antibody rHIgM22. Both these agents have been shown in animal studies to stimulated oligodendrocytes and increase repair of areas of demyelination. Under the action of a remyelinating agent, the oligodendrocyte puts out new extensions that wrap surrounding nerve fibers in fatty layers of membrane to form new myelin. This process helps to restore electrical conduction and may also serve to protect the exposed nerve fiber from further damage.

Other compounds such as GGF2 and M1 have shown the ability to stimulate the regrowth of myelin in animal models.