Microalbuminuria is associated with impaired arterial and venous endothelium-dependent vasodilation in patients with Type 2 diabetes.
BACKGROUND
Microalbuminuria in Type 2 diabetes is associated with arterial endothelial dysfunction, but the venous bed was never evaluated.


OBJECTIVE
To study the endothelial function in the venous and arterial bed in patients with Type 2 diabetes with normoalbuminuria or microalbuminuria.


METHODS
We evaluated 28 patients with Type 2 diabetes, glycated hemoglobin (HbA(₁c)) <7.5%, who were classified as normo- (albuminuria <30 mg/24 h; no.=16) or microalbuminuric (albuminuria 30-300 mg/24 h; no.=12). Venous and arterial endothelial function were assessed by the dorsal hand vein technique (venodilation by acetylcholine) and brachial artery flow-mediated vasodilation, respectively.


RESULTS
Patients were normotensive (systolic arterial pressure: 131.1±10.6 mmHg) and on good metabolic control (HbA(₁c): 6.6±0.6%). Microalbuminuric patients presented impaired venous (32.9±17.4 vs 59.3±26.5%; p=0.004) and arterial vasodilation (1.8±0.9 vs 5.1±2.4; p<0.001), as compared to normoalbuminuric patients. There was a negative correlation between acetylcholine-induced venodilation and albuminuria (r=-0.62; p<0.001) and HbA(₁c) (r=-0.41; p=0.032). The same was observed between flow mediated arterial vasodilation and albuminuria (r=-0.49; p=0.007) and HbA(₁c) (r=-0.44; p=0.019). Venous and arterial vasodilation was positively correlated (r=0.50; p=0.007).


CONCLUSIONS
Both venous and arterial endothelial function are impaired in Type 2 microalbuminuric diabetics, in spite of good metabolic control, suggesting that other factors are involved in its pathogenesis.
Silva
A M V
AM
Department of Physiology, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
Schaan
B D
BD
Signori
L U
LU
Plentz
R D M
RD
Moreno
H
H
Bertoluci
M C
MC
Irigoyen
M C
MC
D000328:Adult; D000368:Aged; D000419:Albuminuria / Q000150:complications* / Q000453:epidemiology / Q000503:physiopathology; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000453:epidemiology / Q000503:physiopathology*; D003925:Diabetic Angiopathies / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D003935:Diagnostic Techniques, Cardiovascular; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D006225:Hand / Q000098:blood supply; D006801:Humans; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow; D014463:Ultrasonography; D014664:Vasodilation / Q000502:physiology; D014680:Veins / Q000503:physiopathology