Numbers of cells and cell proliferation in intima of different human arteries

Increased cell proliferation in early atherosclerotic lesions is recognized as an essential event of atherogenesis but the levels of cell proliferation in different stages of atherosclerotic plague formation in different types of human large arteries are still insufficiently studied. In the present work, we studied intima thickness and proliferation of newly "infiltrates" hematogenous and resident cells in atherosclerotic lesions of the carotid and coronary arteries and compared these parameters with those in the aorta, reported by us in earlier publication. Analysis of intima thickness and proliferation in grossly unaffected intima and in different types pf atherosclerotic lesions (initial lesions, fatty streaks, lipofibrous, plaques, and fibrous plaque) revealed that although there were similar tendencies in the change of the infiltration levels of hematogenous cells and proliferation in different types of arteries, there were significant quantitative differences between different types of arteries. Hematogenous cells in lipofibrous plaques of the coronary and carotid arteries were found to account for a third and almost for a half of the total cell population, respectively, while atherosclerotic lesions in the aorta, as it has been shown by us earlier, to contain no more than 15% ofhematogenous cells. This suggests that the contribution of hematogenous cells to the development of atherosclerosis in the carotid and the coronary artery appears to be more significant than that in the aorta. Despite the differences in numbers of accumulating hematogenous cells in the intima, a similar "bell-shaped" dependence of cell numbers on the lesion type, involved in the following sequence: unaffected intima-initial lesions-fatty streaks-lipofibrous plaques-fibrous plaques, was detected in the coronary and carotid arteries. The visualization of proliferating cells (PCNA-positive) in atherosclerotic and unaffected zones of the coronary and carotid arteries revealed similar patterns. The maximum numbers of PCNA-positive resident cells were identified in lipofibrous plaques. The changes in the total cell numbers were accompanied by the changes in the numbers of both proliferating resident cells and proliferating hematogenous cells.     

The number of cells and the cell proliferation in intima of various human arteries

Increased cell proliferation at the early stages of an atherosclerotic lesion is considered an important stage of development of this pathology, but the degree of the proliferation at various stages of formation of atherosclerotic plaque in various human large arteries so far has been studied insufficiently. In the present work, we studied the thickness of intima and proliferation of the newly “infiltrated” hematogenic and resident cells in atherosclerotic lesion of carotid and coronary arteries; a comparison is also made with similar results obtained on the aorta and presented in our earlier publications. Analysis of thickness of intima and of proliferation in normal intima and at various stages of atherosclerotic lesion (initial stages, lipid strips, lipofibrous plaques, fibrous plaques) showed that, in spite of similar tendencies toward changing the level of infiltration of hematogenic cells and proliferation in various types of arteries, there exist significant quantitative differences between various types of arteries. Thus, it is found that hematogenic cells in lipofibrous plaques of coronary and carotid arteries account for one-third and almost half of the total cell population, respectively, whereas the atherosclerosis-lesioned sites of the aorta, as we showed earlier, contain no more than 15% of hematogenic cells. This allows one to think that the contribution of hemopoietic cells to development of atherosclerosis in carotid and coronary arteries is greater than in the aorta. In spite of differences in the number of the hemopoietic cells accumulating in intima, an analogous bell-shaped dependence of the number of cells on the type of lesion (in the sequence normal intima-initial stages of pathology-lipid strips-lipofibrous plaques-fibrous plaques) was shown for coronary and carotid arteries. Visualization of proliferating (PCNA-positive) cells in atherosclerosed and normal (unchanged) zones of coronary and carotid arteries revealed a similar picture. The maximum number of PCNA-positive resident cells was found in lipofibrous plaques. Changes of the total number of cells were accompanied by a change in the number of proliferating resident and proliferating hematogenic cells.     

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