Abstract 15893: Associations Between Serum Adiponectin, Vascular O2- Generation and NO Bioavailability In Patients With Coronary Atherosclerosis
Background: Evidence suggests that adiponectin, an adipokine produced by adipose tissue, may have an anti-inflammatory and antioxidant role in human atherosclerosis. However, very little is known regarding its role in the regulation of vascular function in patients with atherosclerosis. We examined the impact of circulating adiponectin on vascular superoxide (O2-) generation and nitric oxide (NO) bioavailability in human arteries and veins.
Methods: The study population consisted of 320 patients with coronary atherosclerosis (CAD) undergoing elective coronary bypass operation. Endothelial function was estimated in the brachial artery by flow mediated dilation (FMD), and adiponectin levels were measured in blood obtained preoperatively. Vascular O2- was measured in saphenous veins (SV) and mammary arteries (IMA) in the presence or absence of LNAME (an endothelial nitric oxide synthase (eNOS) inhibitor). NO bioavailability was also estimated in SV segments ex vivo, by determining the vasorelaxations in response to acetylcholine (ACh).
Results: Circulating adiponectin was positively associated with FMD (r=0.310, p=0.032) and vasorelaxations of SV segments in response to ACh (Fig.A). Importantly, adiponectin was negatively associated with vascular O2- in both SV and IMA (Fig. B), while low adiponectin was associated with more LNAME inhibitable O2- in SV and IMA, suggesting more eNOS uncoupling (Fig. C).
Conclusions: This is the first study demonstrating that adiponectin has a direct impact on NO bioavailability in human vessels, by improving eNOS coupling and suppressing vascular O2- generation in patients with atherosclerosis. These novel findings suggest that adiponectin may be directly involved in the regulation of vascular redox state in humans.
- © 2010 by American Heart Association, Inc.