Endogenous adipose-derived factors diminish coronary endothelial function via inhibition of nitric oxide synthase.
Adipocytokines may be the molecular link between obesity and vascular disease. However, the effects of these factors on coronary vascular function have not been discerned. Accordingly, the goal of this investigation was to delineate the mechanisms by which endogenous adipose-derived factors affect coronary vascular endothelial function. Both isolated canine coronary arteries and coronary blood flow in anesthetized dogs were studied with and without exposure to adipose tissue. Infusion of adipose-conditioned buffer directly into the coronary circulation did not change baseline hemodynamics; however, endothelial-dependent vasodilation to bradykinin was impaired both in vitro and in vivo. Coronary vasodilation to sodium nitroprusside was unaltered by adipose tissue. Oxygen radical formation did not cause the impairment because quantified dihydroethidium staining was decreased by adipose tissue and neither a superoxide dismutase mimetic nor catalase improved endothelial function. Inhibition of nitric oxide (NO) synthase with L-NAME diminished bradykinin-mediated relaxations and eliminated the subsequent vascular effects of adipose tissue. In vitro measurement of NO demonstrated that adipose tissue exposure quickly lowered baseline NO and abolished bradykinin-induced NO production. The results indicate that adipose tissue releases factor(s) that selectively impair endothelial-dependent dilation via inhibition of NO synthase-mediated NO production.
Payne
Gregory A
GA
Department of Cellular and Integrative Physiology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA.
Borbouse
Léna
L
Bratz
Ian N
IN
Roell
William C
WC
Bohlen
H Glenn
HG
Dick
Gregory M
GM
Tune
Johnathan D
JD
D054392:Adipokines / Q000378:metabolism*; D000273:Adipose Tissue / Q000201:enzymology*; D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects; D001920:Bradykinin / Q000494:pharmacology; D003326:Coronary Circulation / Q000187:drug effects; D003331:Coronary Vessels / Q000201:enzymology* / Q000473:pathology; D004285:Dogs; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009599:Nitroprusside / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
D054392:Adipokines; D004791:Enzyme Inhibitors; D017382:Reactive Oxygen Species; D014665:Vasodilator Agents; D009599:Nitroprusside; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D001920:Bradykinin; D019331:NG-Nitroarginine Methyl Ester