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Charge effects on chylomicron clearance in rats
M J Callow1, B C Mortimer, T G Redgrave
1Department of Physiology, University of Western Australia, Nedlands, Perth.
Biochemistry and Molecular Biology International
|April 1, 1993
Summary
Dietary cholesterol and cholic acid (CCA) impaired rat plasma clearance of lipid emulsions. Heparin improved clearance in CCA-fed rats, suggesting charge interactions are key in chylomicron metabolism.
Area of Science:
- Lipid metabolism
- Biochemistry
- Physiology
Background:
- Dietary cholesterol and bile acids influence lipid metabolism.
- Chylomicron clearance is essential for dietary fat transport.
- Defective chylomicron remnant uptake can lead to hyperlipidemia.
Purpose of the Study:
- To investigate the impact of a cholesterol/cholic acid (CCA) diet on chylomicron-like emulsion clearance in rats.
- To explore the role of charge interactions in chylomicron metabolism.
Main Methods:
- Rats were fed either a standard chow or a diet enriched with cholesterol/cholic acid (CCA).
- Labeled chylomicron-like emulsions were administered, and their plasma clearance was measured.
- Heparin, lactoferrin, or poly-arginine were injected to assess their effects on emulsion clearance.
- Lipoprotein fractions were analyzed for apolipoprotein E enrichment.
Main Results:
- CCA-fed rats exhibited defective plasma clearance of lipid emulsions compared to chow-fed rats.
- Heparin injection significantly improved emulsion clearance in CCA-fed rats, enriching remnant and HDL lipoproteins with apolipoprotein E.
- Lactoferrin and poly-arginine inhibited emulsion and chylomicron lipid removal in chow-fed rats, with poly-arginine affecting both cholesteryl oleate and triolein.
Conclusions:
- Dietary cholesterol/cholic acid (CCA) impairs chylomicron clearance.
- Charge interactions play a significant role in both lipolysis and remnant uptake during chylomicron metabolism.
- Heparin's ability to improve clearance suggests modulation of charge-dependent interactions.