Role of neutrophils in myocardial ischemia and reperfusion.

In the intact organism, ischemic myocardial injury initiates an acute inflammatory response in which polymorphonuclear leukocytes (PMNs) are major participants. Evidence indicates that the interplaying inflammatory reactions are augmented by reperfusion and that accumulating PMNs can contribute to myocardial damage, eg, by release of oxygen-derived free radicals, proteases, and leukotrienes. In experimental models, interventions aimed at PMN inhibition can exert cardioprotective effects, and some of these strategies raise hope for future clinical applications. A greater understanding of the mechanisms involved in PMN-mediated myocardial damage is necessary for designing a rational approach to reduce the putative detrimental effects of PMNs without antagonizing their favorable consequences in tissue healing.