Urinary adiponectin excretion is increased in patients with overt diabetic nephropathy.
Adiponectin, a novel adipose-derived adipocytokine, has beneficial effects not only on improvement of insulin sensitivity but also on mitigation of vascular damage. To evaluate whether adiponectin is implicated in the pathogenesis of diabetic nephropathy characterized by microvascular damage, we examined urinary and serum adiponectin levels in type 2 diabetic patients with different stages of nephropathy. We first confirmed adiponectin is excreted into urine through Western blot analysis, followed by measurements of urinary and serum adiponectin levels by radioimmunoassay. Interestingly, urinary adiponectin excretion levels were markedly increased in patient group with overt nephropathy relative to the groups without nephropathy and with incipient nephropathy. Surprisingly, serum adiponectin levels were also elevated in patient group with overt nephropathy. Increased urinary adiponectin excretion may result from elevations in circulating adiponectin levels and enhanced filtration of circulating adiponectin through the damaged kidney. Furthermore, adiponectin synthesis in adipose tissue and its secretion into circulating blood may be enhanced to mitigate microvascular damage in the advanced stage of diabetic nephropathy.
Division of Endocrinology, Metabolism and Geriatric Medicine, Department of Internal Medicine, Akita University School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan. koshi@med.akita-u.ac.jp
Jun
J
Koshimura
Hiroki
H
Fujita
Takuma
T
Narita
Takashi
T
Shimotomai
Mihoko
M
Hosoba
Naomi
N
Yoshioka
Masafumi
M
Kakei
Hiromi
H
Fujishima
Seiki
S
Ito
D052242:Adiponectin; D000419:Albuminuria / Q000175:diagnosis; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D003928:Diabetic Nephropathies / Q000097:blood / Q000175:diagnosis / Q000652:urine*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D008875:Middle Aged; D011506:Proteins / Q000032:analysis*
D052242:Adiponectin; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins