ALTERATIONS IN LIPID METABOLISM OF RAT AORTA. EFFECTS OF VITAMIN A DEFICIENCY

LAURA V. GATICA; VERÓNICA A. VEGA; FANNY ZIRULNIK; LILIANA B. OLIVEROS; MARÍA S. GIMÉNEZ

JOURNAL OF VASCULAR RESEARCH.

Karger

Lugar: Munich, Germany; Año: 2006 vol. 43 p. 602 - 610

1018-1172

Antioxidants are known to reduce cardiovascular disease by reducing the concentration of free radicals in the vessel wall and by preventing the oxidative modification of low density lipoproteins. The prooxidative effect of vitamin A- deficient diet in aorta has been previously demonstrated by us. In this study, the lipid metabolism in the aorta of rats fed on a vitamin A deficient diet was evaluated. Vitamin A deficiency induced a hypolipidemic effect (lower serum triglyceride and cholesterol levels) and a decreased serum paraoxonase/arylesterase- 1 (PON-1) activity. In aorta, the concentrations of triglycerides, total cholesterol, free and esterified cholesterol, and phospholipids were increased in vitamin A-deficient rats. The phospholipid compositions showed an increase of phosphatidylcholine (PC), phosphatidylinositol plus phosphalidylserine and phosphatidylethanolamine, a decrease of sphingomyelin, and no change in phosphatidylglycerol. In aorta, the triglycerides increase was associated to an increased fatty acid synthesis and mRNA expression of diacylglycerol acyltransferase-1 (DGAT-1). The increased PC content was attributed to an increased synthesis, as measured by [methyl- 14C]-choline incorporation into PC and high CTP:phosphocholine cytidylyltransferasealpha mRNA expression. The cholesterol synthesis, evaluated by [1-14C]-acetate incorporated into cholesterol, and mRNA expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG- CoAR), did not change. The lipoprotein lipase (LPL) and lectin-like oxidized LDL receptor-1 (LOX-1) mRNA expression levels increased in aorta of vitamin A- deficient animals. The incorporation of vitamin A into the diet of vitamin Adeficient rats reverted all the changes observed. These results indicate that a vitamin Adeficient diet, in addition to having a prooxidative effect, alters the aorta lipid metabolism.