Occurrence of trans fatty acids in rats fed a trans-free diet: a free radical-mediated formation?
Trans isomers of unsaturated fatty acids are absorbed from the diet, due to their presence in diary fat and hydrogenated vegetable oils, and health concern has risen due to their effects on lipid risk factors in cardiovascular diseases. On the basis of the efficiency of the thiyl-radical-catalyzed cis/trans isomerization in vitro and the presence of many sulfur-containing compounds in the cell, the aim of this study was to demonstrate that trans geometry of lipid double bonds can be endogenously generated within membrane phospholipids. The study reports trans fatty acids occurrence in tissue and erythrocyte phospholipids of young adult rats fed a diet completely free of trans isomers. Results show that tissues are differently prone to the endogenous isomerization and that, following a free radical attack, trans fatty acids can reach very high amounts. The effectiveness of this process is considerably inhibited in the presence of all-trans retinol, confirming previous data in model membranes. Our results suggest that geometrical isomerization of unsaturated fatty acids, which causes a structural modification of membrane lipids and may influence basic membrane properties and vital biochemical functions, can occur under radical stress conditions and could be efficiently prevented by vitamin A.
Zambonin
Laura
L
Dipartimento di Biochimica, Università di Bologna, Via Irnerio 48, 40126 Bologna, Italy.
Ferreri
Carla
C
Cabrini
Luciana
L
Prata
Cecilia
C
Chatgilialoglu
Chryssostomos
C
Landi
Laura
L
D000818:Animals; D002251:Carbon Tetrachloride / Q000633:toxicity; D002462:Cell Membrane / Q000737:chemistry* / Q000187:drug effects / Q000528:radiation effects; D004032:Diet; D005609:Free Radicals / Q000009:adverse effects* / Q000378:metabolism / Q000528:radiation effects; D005720:Gamma Rays; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D010743:Phospholipids / Q000737:chemistry* / Q000528:radiation effects; D051381:Rats; D017208:Rats, Wistar; D013237:Stereoisomerism; D044242:Trans Fatty Acids / Q000378:metabolism* / Q000528:radiation effects
D005609:Free Radicals; D010743:Phospholipids; D044242:Trans Fatty Acids; D002251:Carbon Tetrachloride