Granulocyte Capillary Plugging in Myocardial Ischemia
In spite of the relatively small numbers in the circulation, leukocytes have in recent years been recognized as playing a significant role in microvascular perfusion. As a result of their large volume and stiffness, leukocytes have to deform on their passage through the microcirculation. This could lead to a situation where they not only impose a relatively large vascular resistance, but also may obstruct the capillary lumen. In contrast, erythrocytes deform easily at the entrance to capillaries and do not cause obstruction. In addition, granulocytes regularly become attached to the vascular endothelium and, if activated, may release a spectrum of toxic substances to the surrounding tissue, which may lead to membrane damage, cell dysfunction, changes in vascular smooth muscle tone, increased permeability, and other defects. The traditional view that granulocytes participate in the inflammatory reaction and antimicrobal defense may represent only a limited aspect of leukocyte activity. These cells may in fact be the key elements in cell injury, organ dysfunction, necrosis, and death.
KeywordsReperfusion Injury Xanthine Oxidase Capillary Network Stun Myocardium Postcapillary Venule
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