Post-stroke recovery: the role of activity-dependent release of brain-derived neurotrophic factor.

Stroke remains the leading cause of long-term disability with no pharmacological approaches available to limit the degree of damage or aid in recovery. Considerable effort has been made to minimize neuronal damage using neuroprotective compounds. However, attempts have so far failed to translate into the clinic. Brain-derived neurotrophic factor (BDNF) and its receptor tropomyosin-related kinase type B are actively produced throughout the brain and are involved in regulating neuronal activity and normal day-to-day function. Further, BDNF has been shown to play a role in both protection and recovery of functions after stroke. This review focuses on the endogenous release of BDNF as well as activity-induced (pharmacological and physical) elevation in BDNF, and the role this plays during both acute (hours to days) and subacute (days to weeks) periods after stroke. Exogenous administration has previously been shown not to cross the blood-brain barrier; therefore, we have focused this review on approaches that allow us to directly stimulate, using pharmacological therapies and mimetics, physical activity and potential drug delivery systems that can be used to administer BDNF. Finally, we also discuss the role of BDNF polymorphisms and the influence of epigenetic regulation of BDNF on post-stroke recovery.