The Protective Effects of Ischemic Postconditioning against Stroke: From Rapid to Delayed and Remote Postconditioning

The author reviews the protective effects of ischemic postconditioning, a recently emerging strategy with broad implications in the search for new treatments in stroke and myocardial ischemic injury. Ischemic postconditioning, which refers to a series of brief ischemia and reperfusion cycles applied immediately at the site of the ischemic organ after reperfusion, results in reduced infarction in both cerebral and myocardial ischemia. Conventional postconditioning induced within a few minutes after reperfusion is arbitrarily defined as rapid postconditioning. In contrast, postconditioning performed hours to days after stroke is defined as delayed postconditioning. In addition, postconditioning can be mimicked using anesthetics or other pharmacological agents as stimuli to protect against ischemia/reperfusion injury or performed in a distant organ, which is known as remote postconditioning. In this article, the author discusses the conceptual origin of classical rapid ischemic postconditioning and its evolution into a term that represents a broad range of stimuli or triggers, including delayed postconditioning, pharmacological postconditioning, and remote postconditioning. Thereafter, various in vivo and in vitro models of postconditioning and its potential protective mechanisms are discussed. Since the concept of postconditioning is so closely associated with that of preconditioning and both share some common protective mechanisms, whether a combination of preconditioning and postconditioning offers greater protection than preconditioning or postconditioning alone is also discussed.