RESUMO
<p><b>OBJECTIVE</b>To study the expression of COX-2 and pregnancy associate plasma protein A (PAPP-A) in coronary arteries and their relationship with acute coronary syndrome.</p><p><b>METHODS</b>Twenty-one autopsy cases with acute coronary syndrome encountered during the period from 2002 to 2007 were enrolled into the study. Another 21 autopsy cases without evidence of acute coronary syndrome were used as the controls. The right and left coronary arteries of each group were dissected, embedded and processed as paraffin sections. Immunohistochemical study for CD68 and alpha-actin was performed to highlight the presence of macrophages and smooth muscle cells, respectively. The expression of COX-2 and PAPP-A was evaluated.</p><p><b>RESULTS</b>In the acute coronary syndrome group, COX-2 was localized mainly in the cytoplasm of endothelial cells, macrophages and smooth muscle cells. COX-2 expression in the cytoplasm of smooth muscle cells (28.60%) was significantly higher than that in the control group (4.76%, chi(2) = 14.13, P< 0.05). There was a positive correlation on COX-2 and PAPP-A expression in smooth muscle cells of the media layer of coronary arteries in acute coronary syndrome group (r = 0.88, P < 0.05). The expression of PAPP-A in smooth muscle cells of the media layer in coronary arteries not associated with plaque formation, was higher than that when there were atherosclerotic plaques (chi(2) = 10.36, P < 0.05).</p><p><b>CONCLUSION</b>In coronary arteries, COX-2 and PAPP-A play certain roles in the pathogenesis of acute coronary syndrome.</p>