THORACIC AORTA PROSTACYCLIN PRODUCTION IS NOT ALTERED DURING EARLY ATHEROSCLEROSIS DEVELOPMENT IN YOUNG SWINE

Decreased prostacyclin synthesis by atherosclerotic vascular tissue ha s been demonstrated in both adult animal models and man. The purpose o f this study was to determine whether the decrease in prostacyclin syn thesis by the vessel wall was evident during the initial stages of ath erosclerosis development and thus a potential contributor to atherogen esis. Thirty-two Yucatan miniature swine entered the study at 3 months of age and were placed on either an atherogenic or regular diet for 1 0, 30, 90, or 180 days. At that time, the thoracic and abdominal aorta were harvested. Pairs of discs were punched out of the distal thoraci c aorta and placed in Krebs Henseleit HEPES buffer, The buffer was the n exchanged for either fresh buffer or stimulated with calcium ionopho re A23187 (10(-4) M). Aliquots were collected at 10 min for analysis o f prostacyclin production by radioimmunoassay of its stable metabolite 6-keto-prostaglandin F-1 alpha. Thoracic aorta sections were prepared for atherosclerosis assessment by light microscopy, and the abdominal aorta was stained with Sudan N. No significant differences were noted between the diet groups at 10 and 30 days. After 90 days, a significa nt difference was noted (P < 0.05) between the diet groups with regard to (ii the early development of atherosclerosis in the thoracic aorta and (2) the percent of abdominal aorta surface area sudanophilically stained. However, no differences (P > 0.05) were noted between the die t groups with regard to the basal and stimulated rates of prostacyclin production. Our findings showed that prostacyclin synthesis was not a ltered during the initial development or early progression of aortic a therosclerosis induced by hypercholesteralemia.