Cellular proliferation in complicated versus uncomplicated atherosclerotic lesions: Total cell population, foam cells and newly formed microvessels

Although cellular proliferation is a key component in the progression of atherosclerosis, research so far has been focused primarily on VSMCs. In this study we attempted to evaluate overall proliferation rates in general, as well as foam cells and the endothelial cells lining newly formed plaque microvessels in particular. For this purpose, cellular proliferation was assessed through immunohistochemical staining for PCNA in 10 fresh human carotid artery samples received from patients undergoing carotid endarterectomy. Overall proliferative activity was found significantly higher (P ≤ 0.01) among complicated type VI lesions compared to uncomplicated type V lesions. A similar assessment focused on foam cells alone also revealed a significantly higher (P ≤ 0.05) proliferative index among complicated lesions. On the other hand, the proliferation rate for the endothelial cells lining the interior walls of newly formed microvessels was harder to properly assess, since only two of the uncomplicated lesions bore signs of neovascularization. Still, both of these samples displayed proliferation rates similar to those of the complicated type VI lesions. Thus, it seems that, although total cell population and foam cells are probably affected by the stimulating factors that are expressed during acute events, the same does not apply to the endothelial cells lining plaque vessels.