FK506 and nerve regeneration: past, present, and future

Promoting neurological recovery requires strategies that simultaneously provide protection to injured neurons and increase the numbers of neurons that extend axons while inducing more rapid and extensive axon regeneration across long nerve gaps. An agent that facilitates the speed and success of reinnervation will have direct applicability to the clinical management of severe peripheral nerve injuries. The immunosuppressive drug FK506 has been proven to have neuroprotective and neurotrophic actions in experimental models, increasing neurite elongation and accelerating the rate of nerve regeneration in vitro and in vivo. This review examines the role played by FK506, with primary focus on its role as a neurotrophic agent and its potential clinical use as a promoter of neurological recovery following peripheral nerve injuries.