Strategies for achieving and monitoring myelin repair

Vitamins E and D3 attenuate demyelination and potentiate remyelination processes of hippocampal formation of rats following local injection of ethidium bromide

Cognitive deficits have been observed in patients with multiple sclerosis (MS) due to hippocampal insults. Antioxidant vitamins D and E are suggested for patients suffering from neurodegenerative diseases like MS, while their mechanisms of action are not well understood. Here, we have tried to study the effects of these vitamins on demyelination, cell death, and remyelination of rat hippocampus following local ethidium bromide (EB) injection. Animals received 100 mg/kg vitamin E or 5 microg/kg of vitamin D3 for 2, 7, or 28 days. The extent of demyelination, myelin staining intensity, and expression of myelin basic protein and caspase-3 were investigated using histological and immunoblotting verification. Administration of EB alone caused demyelination, cell death, and afterward an endogenous repair. Vitamins E and D3 reduced the EB-induced damage and increased the endogenous remyelination of hippocampus. Although the anti-apoptotic effect of these vitamins and protection against demyelination were predictable based on their antioxidant effect, our results indicated the positive effect of vitamins E and D3 on process of remyelination by endogenous progenitor cells and supported their possible therapeutic effects in the context of demyelinating diseases like MS.

Protecting axons in multiple sclerosis

Typically patients with multiple sclerosis (MS) experience acute episodes of neurological dysfunction, which recover followed, at a later stage, by slow and insidious accumulation of disability (disease progression). Disease progression reflects axon damage and loss within the central nervous system. However, the precise mechanism of axon injury in MS is not clear. Inflammation occurring during acute relapses undoubtedly causes some degree of acute axon damage, but epidemiological data and treatment studies have suggested that inflammation alone is not the sole cause of axonopathy. Indeed, there appears to be dissociation between inflammation and disease progression once a certain level of clinical disability has been reached because immune suppression in patients who have established disease progression does not halt the slow decrease of function. The slow and insidious loss of neurological function that occurs during the progressive phase of the disease implies a degenerative process. Whether axon drop-out occurs at these later stages because of previous inflammatory damage to axons; because of low grade inflammation causing damage to already vulnerable demyelinated axons; because of loss of trophic environment for axons to survive; or as part of a completely independent neurodegenerative process is not clear. Understanding disease mechanisms involved in the axonopathy of MS allows for the development of rational therapies for disease progression.