Strategies for blood-brain barrier rejuvenation and repair

Blood-brain barrier (BBB) dysfunction is a hallmark of many diseases of the brain, including those that represent the largest healthcare burden (for example, Alzheimer disease and stroke). Despite this, rejuvenation and repair of the BBB is not a mainstream concept. During life, the BBB is subjected to perturbations and stresses from a wide range of endogenous or exogenous sources, which can promote brain health or can lead to brain pathologies. The BBB supports many functions that are critical for central nervous system homeostasis and so there are many mechanisms of dysfunction, and hence many targets for intervention. Furthermore, many mechanisms are shared among diseases and disease subtypes, resulting in the potential for common strategies for BBB repair. In this Review, we consider the BBB as a therapeutic target and discuss approaches to its repair and protection in specific disease states and during normal ageing.