Preconditioning in Ischemia-Reperfusion Lesion

Ischemic heart disease is characterized by a decrease in myocardial blood flow, which reduces the relationship between oxygen supply and demand. The condition has attracted the attention of the scientific community due to its high incidence, elevated morbidity and mortality, and high therapeutic cost. The treatment primarily relies on myocardial revascularization. Paradoxically, reperfusion and restoration of blood flow can cause additional damage, called myocardial ischemia-reperfusion (IR) injury. Several mechanisms are involved in the IR injury, such as ionic homeostasis change, intracellular calcium transient alteration, metabolic and mitochondrial dysfunction, inflammation, and reactive oxygen species increase.^, These factors may contribute to an increase in the myocardial necrosis size, post-ischemia heart failure, and death.

First identified in the mid-1980s, ischemic preconditioning is a process whereby repeated application of short periods of ischemia alternating with reperfusion protect the myocardium from longer ischemic insults, therefore reducing the infarction size.^, The beneficial effect of ischemic preconditioning was shown in angina patients; when evolving to myocardial infarction, they had a smaller infarcted area and a better clinical prognosis than previously asymptomatic patients.^, Additionally, preconditioning of rats with acute physical stress prior to the IR insult reduced infarct size and improved hemodynamic parameters.

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