Non-specific esterase activity during regression of swine aortic atherosclerosis

Non-specific esterase (NSE) activity has been studied by light and electron microscopic enzyme histochemistry in lesion and non-lesion areas of swine abdominal aortas in a sequential study of the regression of atherosclerosis. On the light microscope level, no activity was demonstrable in normal artery but in atherosclerotic lesions it was seen in round cells, elongate cells and foamy cells. Ultrahistochemistry identified these reactive cells as macrophages, smooth muscle cells and foam cells of undetermined origin. Since NSE has been shown to hydrolyze cholesteryl oleate, it is possible that histochemical demonstration of NSE activity may be, in part, localization of cholesteryl ester hydrolase activity.