Urinary adiponectin excretion: a novel marker for vascular damage in type 2 diabetes.
OBJECTIVE
Markers reliably identifying vascular damage and risk in diabetic patients are rare, and reports on associations of serum adiponectin with macrovascular disease have been inconsistent. In contrast to existing data on serum adiponectin, this study assesses whether urinary adiponectin excretion might represent a more consistent vascular damage marker in type 2 diabetes.


METHODS
Adiponectin distribution in human kidney biopsies was assessed by immunohistochemistry, and urinary adiponectin isoforms were characterized by Western blot analysis. Total urinary adiponectin excretion rate was measured in 156 patients with type 2 diabetes who had a history of diabetic nephropathy and 40 healthy control subjects using enzyme-linked immunosorbent assay. Atherosclerotic burden was assessed by common carotid artery intima-media-thickness (IMT).


RESULTS
A homogenous staining of adiponectin was found on the endothelial surface of glomerular capillaries and intrarenal arterioles in nondiabetic kidneys, whereas staining was decreased in diabetic nephropathy. Low-molecular adiponectin isoforms ( approximately 30-70 kDa) were detected in urine by Western blot analysis. Urinary adiponectin was significantly increased in type 2 diabetes (7.68 +/- 14.26 vs. control subjects: 2.91 +/- 3.85 microg/g creatinine, P = 0.008). Among type 2 diabetic patients, adiponectinuria was associated with IMT (r = 0.479, P < 0.001) and proved to be a powerful independent predictor of IMT (beta = 0.360, P < 0.001) in multivariable regression analyses. In a risk prediction model including variables of the UK Prospective Diabetes Study coronary heart disease risk engine urinary adiponectin, but not the albumin excretion rate, added significant value for the prediction of increased IMT (P = 0.007).


CONCLUSIONS
Quantification of urinary adiponectin excretion appears to be an independent indicator of vascular damage potentially identifying an increased risk for vascular events.
von Eynatten
Maximilian
M
Department of Nephrology, Technische Universitat Muenchen, Munich, Germany. maximilian.eynatten@lrz.tum.de
Liu
Dan
D
Hock
Cornelia
C
Oikonomou
Dimitrios
D
Baumann
Marcus
M
Allolio
Bruno
B
Korosoglou
Grigorios
G
Morcos
Michael
M
Campean
Valentina
V
Amann
Kerstin
K
Lutz
Jens
J
Heemann
Uwe
U
Nawroth
Peter P
PP
Bierhaus
Angelika
A
Humpert
Per M
PM
D052242:Adiponectin / Q000652:urine; D000368:Aged; D015415:Biomarkers / Q000652:urine*; D001706:Biopsy; D015153:Blotting, Western; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000652:urine; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000652:urine*; D003925:Diabetic Angiopathies / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000652:urine*; D003928:Diabetic Nephropathies / Q000453:epidemiology / Q000473:pathology / Q000652:urine; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007668:Kidney / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012307:Risk Factors; D014463:Ultrasonography
C499918:ADIPOQ protein, human; D052242:Adiponectin; D015415:Biomarkers