Seeing is believing: Identifying remyelination in the central nervous system.

Remyelination is the regenerative process by which lost myelin sheaths are restored to demyelinated axons. It is a key target in the treatment of chronic demyelinating disorders such as multiple sclerosis (MS), in which inflammation results in destruction of myelin. In the central nervous system (CNS), remyelination typically requires the differentiation of oligodendrocyte progenitor cells (OPCs) into the myelinating oligodendrocytes (OL). Following successes in preclinical studies, several putative pro-regenerative therapies aimed at enhancing remyelination are under clinical investigation. However, there is a translational barrier in identifying successful outcomes: preclinical measures of remyelination do not translate well to clinical studies, and the paraclinical measures currently deployed in trials are challenging to apply to small rodent models of remyelination. Here, we describe the current approaches to identifying remyelination both in preclinical and clinical settings and highlight exciting translational candidates, which may help to bridge the current impasse.