The Protective Role of Adiponectin against Cerebral Ischemic Injury—Evidence from in vivo and in vitro Studies

Adiponectin (APN) is an adipokine abundant in circulation. Its main physiological function is involved
in insulin sensitivity and regulation of metabolism of glucose and lipids. Besides, it has pleiotropic
effects including anti-inflammation, anti-atherosclerosis, anti-thrombosis, promotion of endothelial
repair, and angiogenesis which are protective in endothelial injury, atherosclerosis, and
cardiovascular diseases. Evidence from current in vivo and in vitro studies indicate adiponectin has a
pivotal role against cerebral ischemic injury. Adiponectin is found in vascular endothelium after
cerebral ischemic injury due to exogenous accumulation from the circulation but not endogenous
production in ischemic brain tissues. Adiponectin alleviates cerebral ischemic injury through multimechanisms,
including eNOS-dependent mechanism, anti-inflammation, anti-oxidation, antiapoptosis,
and promotion of angiogenesis. Furthermore, APN-gene modified cell therapy can alleviate
cerebral ischemic injury. Among adiponectin isoforms, the globular adiponectin is mostly studied and
proved to be beneficial in the treatment of cerebral ischemic injury. Since adiponectin is secreted
naturally by human adipocytes with a relatively large amount in the peripheral circulation and has
multi-mechanisms against cerebral ischemic injury, it is of great potential in the application of clinical
treatment of ischemic stroke in the future.