Topographic Analysis of Proliferative Activity in Carotid Endarterectomy Specimens by Immunocytochemical Detection of the Cell Cycle–Related Antigen Ki-67

Background On the basis of contradictory results found in animal experiments and coronary atherectomy tissue, there is an ongoing debate about the significance of cellular proliferation in human atherosclerosis. In the present prospective study, the cell cycle–related antigen Ki-67 was detected for topographic determination of cell turnover in distinct regions of human carotid endarterectomy specimens harvested en bloc by surgical biopsy. Methods and Results After en bloc resection, serial sections of 26 consecutive carotid lesions were analyzed by histomorphological examination and immunohistochemistry. Thereby, 319 high-power fields were attributed to separate plaque regions defined as follows: distal boundary of the lesion with normal intima, plaque shoulder, core region, and diffuse intimal thickening. Endothelial cells, smooth muscle cells, T cells, and macrophages were identified by immunostaining of factor VIII–related protein, α-actin, CD68, and CD45R0. An overall proliferation index of 0.49±1.05%...