title: Cholesterol efflux and the effect of combined treatment with niacin and chromium on aorta of hyperlipidemic rat.
abstract: Endothelial cells may play a potential role in cholesterol efflux from peripheral tissues to liver. Cholesterol efflux from cells is essential for activation of the reverse cholesterol transport pathway and cardiovascular health. One of the cholesterol transporters is steroidogenic acute regulatory protein (StAR) which promotes intramitochondrial delivery of cholesterol to the cholesterol side-chain cleavage system. The aim of the present study was to determine the effects of a niacin-chromium complex on aortas of hyperlipidemic rats and on the cholesterol efflux from aorta endothelial cells by examination under light and transmission electron microscopes and evaluating the StAR immunoreactivity, respectively. Aorta lipid peroxidation (LPO) and glutathione (GSH) levels were determined by spectrophotometric methods. After treating hyperlipidemic animals with the complex, the StAR immunoreactivity in endothelial cells increased to achieve cholesterol homeostasis and efflux. Combined treatment with niacin and chromium resulted in an inhibition in the mast cell secretion and a decrease in lipid vacuole size in unilocular adipose tissue surrounding aorta, as well as in a decrease in morphological degenerations observing in aorta of hyperlipidemic rats. Aorta LPO levels increased and GSH levels decreased in the hyperlipidemic group, whereas treatment with niacin and chromium reversed these effects. In conclusion, this study reveals that combined treatment with niacin and chromium prevents the morphological and biochemical changes observed in thoracic aorta of hyperlipidemic rats, and may regulate effectively cardiovascular diseases inducing an increase in StAR levels on endothelial cells.
authors.affiliation: Faculty of Science, Department of Biology, Zoology Section, Istanbul University, Vezneciler, 34459 Istanbul, Turkey. songulsuren@yahoo.com
authors.forename: Songul
authors.initials: S
authors.lastname: Suren Castillo
authors.forename: M Mutluhan
authors.initials: MM
authors.lastname: Doger
authors.forename: Sehnaz
authors.initials: S
authors.lastname: Bolkent
authors.forename: Refiye
authors.initials: R
authors.lastname: Yanardag
mesh_terms: D000273:Adipose Tissue / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure; D000818:Animals; D001011:Aorta / Q000187:drug effects* / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D002784:Cholesterol / Q000378:metabolism*; D002857:Chromium / Q000494:pharmacology*; D004357:Drug Synergism; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D005260:Female; D005978:Glutathione / Q000378:metabolism; D006949:Hyperlipidemias / Q000378:metabolism* / Q000473:pathology*; D007150:Immunohistochemistry; D015227:Lipid Peroxidation / Q000187:drug effects; D008407:Mast Cells / Q000187:drug effects; D008854:Microscopy, Electron; D009525:Niacin / Q000494:pharmacology*; D010750:Phosphoproteins / Q000378:metabolism; D051381:Rats; D017540:Tunica Media / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: D010750:Phosphoproteins; D000098682:Steroidogenic Acute Regulatory Protein; D002857:Chromium; D009525:Niacin; D002784:Cholesterol; D005978:Glutathione