Influx of neutrophils into the walls of large epicardial coronary arteries in response to ischemia/reperfusion.

Abstract

Background. There are several clinical situations in which large epicardial coronary arteries are deprived of blood flow, such as occurs when an obstructing thrombus or embolus lodges within a vessel or during coronary dissection. There is little information concerning the effect of flow deprivation on large epicardial coronary arteries.Methods and Results. We studied a model in which a segment of a large epicardial coronary artery was deprived of blood flow using both proximal and distal clamps for 3 hours followed by reperfusion. On examination by light microscopy of cross sections of the arteries, 19±t6 neutrophils were present in the intima of ischemic/reperfused vessels, whereas only a mean of 4±3 (SEM) were present in the intima of nonischemic vessels (p<0.02). On average, there were 17±9 neutrophils just under the elastic lamina in ischemic/reperfused vessels versus none in the nonischemic vessels (p<0.05); there were 16± 10 neutrophils present within the media of ischemic/reperfused vessels, and none (p<0.05) in the nonischemic vessels. Electron microscopic analysis revealed that neutrophils in the ischemic/reperfused vessels were often "sandwiched" between the endothelial cells and the elastic lamina. Ultrastructural abnormalities within the myocardium also revealed damage to the microvasculature, including the presence of neutrophils within the vessels and erythrocyte stasis. To rule out the possibility that

Detection of Acutely Impaired Microvascular Reperfusion After Infarct Angioplasty With Magnetic Resonance Imaging

“…17 Previously, the lack of recovery in the region of infarction despite restoration of patency to the IRA has been attributed largely to "reperfusion injury" mediated through myocardial apoptosis, 18 the generation of free radicals, 19 and associated inflammatory response. 20 Our findings extend previous work highlighting impaired microvascular perfusion in AMI despite conventionally successful reperfusion therapy, with a low likelihood of recovery of function in these affected regions. Many of the proposed mediators, such as microvascular spasm, 21 platelet plugging, and distal embolization, are treatable in the acute period.…”

Estrogen Modulates Inflammatory Mediator Expression and Neutrophil Chemotaxis in Injured Arteries

“…28,29 These acute-injury responses may play important roles in many pathological conditions, including acute coronary syndromes, as demonstrated by experimental and autopsy histological studies that show neutrophil infiltration. 30,31 An intervention that attenuates the processes that lead to acute neutrophil recruitment might have far-reaching vasoprotective implications.…”

Relationship of admission hematological indexes with myocardial reperfusion abnormalities in acute ST segment elevation myocardial infarction patients treated with primary percutaneous coronary interventions

“…Adhesion of platelets to circulating myeloid leukocytes in vitro and in vivo is related to platelet activation (26). It is known that reperfusion of the ischemic myocardium often leads to rapid accumulation and adhesion of leukocytes to the endothelium, which are supposed to be the initial steps of leukocyte-mediated reperfusion injury (27,28). We might speculate that patients with a higher MPV have a higher potential for platelet-leukocyte interaction and thus, are more prone to platelet-activated, leukocyte-mediated reperfusion injury.…”