Endothelial injury and leukocyte adherence in Häutchen preparations from coronary arteries and aorta of cynomolgus monkeys.

The aim was to describe the production of en face preparations (Häutchens) of the endothelium from the aorta and the coronary arteries of cynomolgus monkeys (Macaca fascicularis), to describe the morphology of the endothelium and to estimate endothelial injury. The present study describes, for the first time, the application of this technique to the coronary arteries. Numerous leukocytes (peroxidase-positive and -negative cells) were observed on the endothelium and a positive correlation between the numbers of adherent leukocytes and injured endothelial cells was found. A relatively leukocyte-independent measure of endothelial injury in the aorta was obtained by counting areas with a restricted number of leukocytes. The results indicated an even distribution and a relatively low frequency of injured endothelial cells along the arterial tree. The percentage of injured endothelial cells in LAD and LCX was 0.18 and 0.16, and in non-branched and circumostial areas of the descending thoracic aorta the corresponding figures were 0.22 and 0.28. There were, on average, 344 and 236 adherent leukocytes/mm2 in the non-branched and circumostial areas of the descending thoracic aorta, respectively, compared to 13 in the LAD and 23 in the LCX. Proportionally more peroxidase-positive leukocytes (possibly granulocytes) were found on the coronary endothelium than on the aortic endothelium, and the peroxidase-positive cells were preferentially located around small artery branches in the coronary arteries. The foregoing data provide an estimate of the distribution and frequency of endothelial injury and adherent leukocytes at pathobiologically relevant arterial sites in unmanipulated cynomolgus monkeys, an animal frequently used in atherosclerosis research.