High-fat feeding reduces endothelium-dependent vasodilation in rats: differential mechanisms for saturated and unsaturated fatty acids?
1. Chronic feeding with a high-fat diet can cause metabolic syndrome in rodents similar to humans, but the role of saturated versus unsaturated fats in vascular tension remains unclear. 2. The present study shows that rats on a diet rich in either saturated or unsaturated fat had higher blood pressure compared with chow-fed rats (approximately 130 vs 100 mmHg, respectively), along with hyperlipidaemia and insulin resistance. Compared with responses of phenylephrine-preconstricted artery segments from chow-fed rats, vasorelaxation of isolated renal arteries from high-fat fed rats was reduced substantially (> 50%) in response to acetylcholine (0.01-10 micromol/L) and moderately to nitroprusside (>or=1 micromol/L) at low concentrations. Acetylcholine-induced vasorelaxation of arteries from high-fat fed rats was also more sensitive to inhibition by the nitric oxide (NO) synthase inhibitors NG-nitro-L-arginine and methylene blue. 3. In human umbilical vein endothelial cells, the production of NO and endothelin-1 was significantly inhibited by unsaturated fatty acids. In comparison, saturated fatty acids stimulated endothelin-1 production without altering NO production. 4. The data indicate that both saturated and unsaturated high-fat feeding may result in an increase in blood pressure owing to reduced endothelium-dependent vasorelaxation in the arterial system. The impaired endothelium-dependent vasorelaxation induced by saturated and unsaturated fatty acids may involve different mechanisms.
Song
Guang-Yao
GY
Institute of Geriatric Medicine, General Hospital of Hebei Province, Shijiazhuang, Hebei, China. sguangyao@sohu.com
Gao
Yu
Y
Di
Yu-Wei
YW
Pan
Li-Li
LL
Zhou
Yu
Y
Ye
Ji-Ming
JM
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002478:Cells, Cultured; D002784:Cholesterol / Q000097:blood; D018752:Diet, Fat-Restricted; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D019332:Endothelin-1 / Q000235:genetics / Q000378:metabolism; D005227:Fatty Acids / Q000008:administration & dosage / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000139:chemically induced / Q000503:physiopathology*; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012077:Renal Artery / Q000187:drug effects* / Q000503:physiopathology; D014280:Triglycerides / Q000097:blood; D014664:Vasodilation; D014665:Vasodilator Agents / Q000494:pharmacology
D019332:Endothelin-1; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D012333:RNA, Messenger; D014280:Triglycerides; D014665:Vasodilator Agents; D009569:Nitric Oxide; D002784:Cholesterol; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; D000109:Acetylcholine