Regression of naturally occurring atherosclerotic lesions in pigeon aorta by intestinal bypass surgery. Early changes in arterial cholesteryl ester metabolism.

Early changes in cholesteryl ester metabolism of the aorta during the regression of naturally occurring atherosclerotic lesions in pigeon aorta by ileal bypass surgery were examined. Three months after surgery, there was a decrease (50%) in the content of cholesteryl esters in the aorta. Increases in the activity of cholesteryl ester hypdrolase in the lysosomal (P less than 0.05) and the supernatant (P less than 0.01) fractions of the aorta also occurred at this time. There were no differences in the activity of cholesteryl ester synthetase and in the plasma levels of cholesterol and triglycerides between the ileal bypass group and the controls. These results suggest that ileal bypass surgery decreases the level of cholesteryl esters in the aorta, probably because of enhanced cholesteryl ester hydrolysis.

Age-related interrelationships of blood pressure and arterial sterol accumulation in spontaneously atherosclerosis-susceptible and atherosclerosis-resistant pigeons.

Interrelationships of arterial sterol accumulation and blood pressures were examined in age-matched White Carneau and Show Racer pigeons. It was found that the systolic blood pressure of White Carneaux changed from 155.0 mm Hg at nine months of age to 168.8 mm Hg at 17 months of age (P less than 0.005) while that of the Show Racers did not show any age-related increases. In White Carneaux, the total sterol content in the aorta increased by 43.6% from 9 months to 17 months of age (P less than 0.001) with major changes in the steryl ester fraction while no such changes were evident in the Show Racers. This indicates interrelationships of the arterial sterol content and blood pressure in the White Carneau pigeon.

Human intestinal specificity toward dietary sterols studied by balance methods.

Human intestinal specificity toward sterols was studied by a balance method in 10 hyperlipoproteinemic patients fed plant sterol mixture with chromium sesquioxide as fecal flow marker. The mean fecal recovery of campesterol (C28) was 20% less than that of beta-sitosterol (C29). This difference persisted when corrected for fecal flow (by marker recovery), indicating differences in their intestinal uptake (C28 greater than C29). The ratio of fecal cholesterol to its 5beta-reduction products was lower than that of beta-sitosterol in all patients; in vitro, 5beta-reduction of both sterols was similar. The recovery of sterols from patients was unrelated to their 5beta-reduction in the intestine.