PROLIFERATIVE ACTIVITY IN PERIPHERAL AND CORONARY ATHEROSCLEROTIC PLAQUE AMONG PATIENTS UNDERGOING PERCUTANEOUS REVASCULARIZATION

We evaluated the proliferative activity of human atherosclerotic lesio ns associated with active symptoms of ischemia, by assessing the expre ssion of the proliferating cell nuclear antigen (PCNA). We confirmed i n vitro that PCNA, an essential component of the DNA synthesis machine ry, is selectively expressed in proliferating human vascular smooth mu scle cells. 37 atherosclerotic lesions (18 primary and 19 restenotic) retrieved by directional atherectomy from either coronary or periphera l arteries were then studied for the expression of PCNA, using in situ hybridization or immunohistochemistry. Among plaques studied by in si tu hybridization, 7 out of 11 primary and 11 out of 11 restenotic lesi ons contained PCNA-positive cells. The mean rate of proliferation (per cent of PCNA-positive cells) was 7.2+/-10.8% in primary lesions and 20 .6+/-18.2% in restenotic lesions (P < 0.05). Among specimens studied b y immunohistochemistry, five out of seven primary and eight out of eig ht restenotic lesions contained proliferating cells. The mean rate of proliferation was again higher in the restenotic (15.2+/-13.6%) than p rimary (3.6+/-3.5%) lesions (P < 0.05). Proliferating cells were detec ted as late as 1 yr after angioplasty. We conclude that cellular proli feration is a feature of atherosclerotic lesions which are associated with symptoms of ischemia, but that it is more prominent in restenosis compared to primary lesions. These findings have implications for the rapies aimed at limiting lesion growth, particularly after percutaneou s revascularization.