EVIDENCE OF APOPTOSIS IN HUMAN CAROTID ATHEROMA

Purpose: Apoptosis is a morphologically distinct form of programmed ce ll death that plays a major role in cellular development and homeostas is. In this study, we examined the role that apoptosis may have in the pathogenesis of atherosclerosis. Methods: We examined immunohistochem ically 20 normal carotid arteries and the carotid arteries of 86 patie nts (mean age, 68 years; range, 52 to 80 years) who underwent atherect omy for primary atherosclerosis. The expression of two genes, BCL2, wh ich inhibits apoptosis, and BAX, which induces apoptosis, was examined and correlated to the presence of risk factors that included hyperten sion, smoking, hyperlipidemia, and diabetes mellitus. Results: BAX exp ression was found in 26 of 86 cases (30%), arid no immunoreactivity wa s found in the normal carotid specimens. BCL2 expression was not seen in any examined tissues (atherosclerotic or normal carotid arteries). Of the 26 patients who expressed the BAX gene, 22 were hypertensive (8 5%), and hypertension (> 160/95 mm Hg) was present in 25 of 60 patient s (41%) who did not express the BAX gene (p < 0.01). No significant co rrelation was found between the expression of the BAXgene and other ri sk factors (smoking, hyperlipidemia, diabetes mellitus) or presenting symptoms. Conclusions: In a significant number of stenosed carotid art eries (30%), we found no evidence of apoptosis suggested by the presen ce of BAX expression. Hypertension was more prevalent in those patient s with BAX gene expression than in those patients without BAX gene exp ression. BCL2 expression, which inhibits apoptosis, was not found. fur ther study of this phenomenon may contribute to the discovery of new t reatments for atherosclerosis.