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Simvastatin improves chylomicron remnant removal in familial combined hyperlipidemia without changing chylomicron
M C Cabezas1, T W de Bruin, L A Kock
1Department of Internal Medicine, University Hospital, Utrecht, The Netherlands.
Insights
Simvastatin treatment improved lipid profiles in familial combined hyperlipidemia (FCH) patients by reducing cholesterol and apolipoprotein B. However, it did not significantly alter postprandial chylomicron remnant clearance in FCH subjects.
Area of Science:
- Cardiovascular Medicine
- Lipid Metabolism
- Pharmacology
Background:
- Familial combined hyperlipidemia (FCH) is a common genetic dyslipidemia.
- The impact of HMG-CoA reductase inhibitors on postprandial lipoprotein metabolism in FCH is not well understood.
- Atherogenic chylomicron remnant clearance is a key factor in cardiovascular disease.
Purpose of the Study:
- To investigate the effect of simvastatin on postprandial chylomicron remnant clearance in patients with FCH.
- To assess the impact of simvastatin on overall postprandial lipoprotein metabolism in FCH.
- To evaluate changes in key lipoprotein parameters and enzyme activities.
Main Methods:
- A study involving nine normolipidemic controls and seven FCH patients.
- Oral vitamin A-fat load test (24 hours, 50 g/m2) administered before and after simvastatin treatment.
- Measurement of plasma lipids, apolipoproteins, retinyl palmitate, and postheparin lipoprotein lipase (LPL) and hepatic lipase (HL) activities.
Main Results:
- Simvastatin significantly reduced plasma cholesterol (16%) and apolipoprotein B (19%) in FCH patients.
- Plasma apo E levels decreased by 29%, while very-low-density lipoprotein (VLDL) levels were reduced.
- Postprandial chylomicron remnant clearance, measured by retinyl palmitate levels, did not change significantly with simvastatin treatment.
Conclusions:
- Simvastatin effectively improves fasting lipid profiles in FCH patients.
- Despite improvements in fasting lipids, simvastatin does not significantly enhance postprandial chylomicron remnant clearance in FCH.
- Further research is needed to fully elucidate the role of statins in postprandial lipid metabolism in FCH.
Abstract:
It is unknown whether the clearance of atherogenic chylomicron remnants and the postprandial lipoprotein metabolism in general can be improved by 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors in subjects with familial combined hyperlipidemia (FCH). Therefore, the postprandial chylomicron remnant clearance was studied in nine normolipidemic untreated controls and seven FCH patients before and after treatment with simvastatin using an oral vitamin A-fat load (24 hours, 50 g/m2). Treatment with simvastatin reduced plasma cholesterol level by 16% (mean +/- SEM, 8.1 +/- 0.8 v 6.8 +/- 0.8 mmol/L; P < .05) and plasma apolipoprotein (apo) B level by 19% (1.6 +/- 0.2 v 1.3 +/- 0.2 g/L; P < .05). Plasma apo E level (89.6 +/- 21.0 mg/L) was reduced by 29% (63.5 +/- 14.1 mg/L; P < .05). High-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) levels did not change; consequently, the reductions seen had been due to a decrease in very-low-density lipoprotein (VLDL) levels. Fasting plasma triglyceride (30% reduction) and plasma apo C-II (31% reduction) levels did not change significantly. Mean postheparin plasma lipoprotein lipase (LPL) activity increased by 13% after treatment (90.4 +/- 19.8 v 102.6 +/- 20.3 mU/mL; P < .05), but hepatic lipase (HL) activity was not altered. The clearance of chylomicrons (Sf > 1,000), expressed as the area under the 24-hour retinyl palmitate curve, did not change with simvastatin (52.8 +/- 12.9 v 51.8 +/- 13.4 h.mg-1/L).(ABSTRACT TRUNCATED AT 250 WORDS)