Adiponectin is associated with vascular function independent of insulin sensitivity.
OBJECTIVE
Adiponectin has been proposed to play important roles in the regulation of energy homeostasis and insulin sensitivity. In experimental studies, adiponectin has also been found to inhibit vascular smooth muscle cell proliferation. Decreased adiponectin levels have been described in patients with coronary artery disease, and circulating adiponectin predicts cardiovascular death in patients with renal failure. Because adiponectin appears to influence both insulin sensitivity and vessel wall physiology, we examined insulin sensitivity and vascular function in relation with circulating adiponectin.


METHODS
We studied brachial artery vascular reactivity (high-resolution external ultrasound) and insulin sensitivity (minimal model) in 68 healthy subjects. Brachial artery vascular reactivity was also determined in 52 patients with altered glucose tolerance: 30 subjects with impaired fasting glucose (IFG) or glucose intolerance (GIT) and 22 patients with type 2 diabetes.


RESULTS
Circulating adiponectin concentration was significantly associated with insulin sensitivity (r=0.29, P=0.02) and with fasting serum triglycerides (r=-0.29, P=0.02) in healthy subjects. In the latter, adiponectin levels were positively associated with arterial vasodilation in response to nitroglycerin (endothelium-independent vasodilation [EIVD], r=0.41, P=0.002) but not with flux-induced, endothelium-dependent vasodilation (EDVD) (r=0.007, P=NS). In contrast, EIVD was not significantly associated with adiponectin in subjects with IFG, GIT, or type 2 diabetes (r < or =0.10, P=NS). In a multiple linear regression analysis to predict EIVD in healthy subjects, age (P=0.012), sex (P=0.042), and adiponectin concentration (P=0.045), but not BMI, insulin sensitivity, or fasting triglycerides, contributed to 39% of EIVD variance.


CONCLUSIONS
Serum adiponectin concentration appears to be significantly associated with vascular function in apparently healthy humans. This association seems to be independent of its link with insulin sensitivity.
Unitat de Diabetologia, Endocrinologia i Nutricio and Servei de Medicina Interna, University Hospital of Girona Dr Josep Trueta, Girona, Spain. uden.jmfernandezreal@htrueta.scs.es
José-Manuel
JM
Fernández-Real
Antoni
A
Castro
Gabriel
G
Vázquez
Roser
R
Casamitjana
Abel
A
López-Bermejo
Georgina
G
Peñarroja
Wifredo
W
Ricart
D052242:Adiponectin; D015415:Biomarkers / Q000097:blood; D001794:Blood Pressure; D015992:Body Mass Index; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000502:physiology* / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D005260:Female; D018149:Glucose Intolerance / Q000503:physiopathology*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000000981:diagnostic imaging / Q000502:physiology* / Q000503:physiopathology; D011506:Proteins / Q000032:analysis*; D012016:Reference Values; D012907:Smoking; D014463:Ultrasonography
D052242:Adiponectin; D015415:Biomarkers; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins