title: Hypoadiponectinemia is associated with impaired endothelium-dependent vasodilation.
abstract: Adiponectin may have an antiatherogenic effect by reducing endothelial activation. We hypothesized that plasma adiponectin levels were correlated with endothelial function. Plasma adiponectin level was determined by an in-house RIA assay using a rabbit polyclonal antibody in 73 type 2 diabetic patients and 73 controls. Endothelium-dependent and independent vasodilation of the brachial artery was measured by high-resolution vascular ultrasound. Plasma adiponectin level was lower in diabetic patients than in controls (4.73 +/- 1.96 vs. 7.69 +/- 2.80 microg/ml, respectively; P < 0.001), and they also had impaired endothelium-dependent (5.6 +/- 3.6 vs. 8.6 +/- 4.5%, respectively; P < 0.001) and -independent vasodilation (13.3 +/- 4.9 vs. 16.5 +/- 5.6%, respectively; P < 0.001). Plasma adiponectin correlated with endothelium-dependent vasodilation in controls (P = 0.02) and diabetic patients (P = 0.04). On general linear-model univariate analysis, brachial artery diameter, the presence of diabetes, plasma adiponectin, and high-density lipoprotein were significant independent determinants of endothelium-dependent vasodilation. In vitro experiments showed that endothelial cells expressed adiponectin receptors, and adiponectin increased nitric oxide production in human aortic endothelial cells. In conclusion, low plasma adiponectin level is associated with impaired endothelium-dependent vasodilation, and the association is independent of diabetes mellitus. Adiponectin may act as a link between adipose tissue and the vasculature.
authors.affiliation: Department of Medicine, University of Hong Kong. kcbtan@hkucc.hku.hk
authors.forename: K C B
authors.initials: KC
authors.lastname: Tan
authors.forename: A
authors.initials: A
authors.lastname: Xu
authors.forename: W S
authors.initials: WS
authors.lastname: Chow
authors.forename: M C W
authors.initials: MC
authors.lastname: Lam
authors.forename: V H G
authors.initials: VH
authors.lastname: Ai
authors.forename: S C F
authors.initials: SC
authors.lastname: Tam
authors.forename: K S L
authors.initials: KS
authors.lastname: Lam
mesh_terms: D052242:Adiponectin; D001011:Aorta / Q000166:cytology / Q000378:metabolism; D001916:Brachial Artery / Q000503:physiopathology; D016022:Case-Control Studies; D002478:Cells, Cultured; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008075:Lipoproteins, HDL / Q000097:blood; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000096:biosynthesis; D011506:Proteins / Q000378:metabolism* / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000378:metabolism; D014463:Ultrasonography; D014664:Vasodilation
chemical_list: D052242:Adiponectin; D036341:Intercellular Signaling Peptides and Proteins; D008075:Lipoproteins, HDL; D011506:Proteins; D011956:Receptors, Cell Surface; D009569:Nitric Oxide