Lack of effect of captopril on the metabolism of an artificial lipid emulsion similar to chylomicrons in hypertensive hypercholesterolemic patients

OBJECTIVE: To assess the effect of captopril, an angiotensin-converting enzyme inhibitor, on the metabolism of chylomicrons and their remnants and the possible alterations in the concentrations of plasma lipids caused by the drug in hypertensive hypercholesterolemic individuals. METHODS: The metabolism of chylomicrons was tested with the method of artificial lipid emulsion of chylomicrons labeled with ³H-cholesteryl oleate. The emulsion was injected intravenously in 10 patients with mild-moderate arterial hypertension before and 45 days after treatment with captopril (50 mg/day). After injection, blood samples were collected during 60 minutes at pre-established time intervals for determining the decay curve, the fractional catabolic rate (FCR in min-1), and the plasma residence time of the artificial lipid emulsion by analyzing different compartments. The plasma concentrations of the lipids were also assessed before and after treatment. RESULTS: The fractional catabolic rate (min-1) of the lipid emulsion before and after treatment with captopril (0.012±0.003 and 0.011±0.003, respectively; p=0.85, n.s.) and the plasma residence time of the emulsion (83.3±20.8 and 90.9±22.5 min, n.s.) did not change, but the total cholesterol and LDL-C levels decreased by 7% and 10%, respectively (p=0.02). The concentrations of HDL-C, triglycerides, Lp(a), and apolipoproteins AI and B did not change. CONCLUSION: Treatment with captopril, evaluated with the artificial lipid emulsion method, does not cause deleterious changes in the metabolism of chylomicrons and their remnants.