Effect of nutritional vitamin A deficiency on lipid metabolism in the rat heart: Its relation to PPAR gene expression

VEGA VA; ANZULOVICH AC; VARAS SM; BONOMI MR; GIMÉNEZ MS; OLIVEROS L

NUTRITION

Elsevier Inc.

Año: 2009 vol. 25 p. 828 - 838

0899-9007

Objective: We studied the effect of dietary vitamin A deprivation on lipid composition and mRNA expression of regulatory enzymes involved in rat heart energetic lipid metabolism and its relation to the expression of peroxisome proliferator-activated receptor (PPAR) and retinoid X receptor (RXR) genes. Methods: Male Wistar 21-d-old rats were fed for 3 mo with a vitamin A–free diet (vitamin A–deficient group) and the same diet plus 8 mg of retinol palmitate per kilogram of diet (control group). One group of deficient animals received the control diet 15 d before sacrifice (vitamin A–refed group). Heart ventricular and mitochondrial lipid contents were determined. Lipid synthesis was measured using radioactive precursors and acetyl-coenzyme A carboxylase and mitochondrial carnitine palmitoyltransferase-I (CPT-I) activities using radioactive substrates. Fatty acid composition of mitochondrial phospholipids was analyzed by gas–liquid chromatography. Heart expression of acetyl-coenzyme A carboxylase, CPT-I, PPAR-, PPAR-[1], RXR-, and RXR-[1] was assessed by reverse transcriptase polymerase chain reaction, and CPT-I expression was also measured by real-time polymerase chain reaction. Results: Vitamin A deficiency induced changes in heart ventricular lipid content and synthesis. Mitochondrial cardiolipin decreased and the proportion of phospholipids/saturated fatty acids increased. Heart activity and mRNA levels of CPT-I and expression of PPAR- and PPAR-[1] genes were enhanced, whereas acetyl-coenzyme A carboxylase activity diminished. Furthermore, vitamin A deficiency decreased heart mRNA levels of RXRs. Vitamin A refeeding reverted most of the observed changes. Conclusion: Lipid metabolism is significantly modified in hearts of vitamin A–deficient rats. Alteration of mitochondrial energetic processes by modifying the activity and gene expressions of the regulatory enzymes is associated with a high PPAR expression induced by vitamin A deprivation. © 2009 Published by Elsevier Inc.