title: Relationship between serum irisin levels and urinary albumin excretion in patients with type 2 diabetes.
abstract: OBJECTIVE
  Irisin is first discovered as a potential mediator of obesity related energy homeostasis. Recent studies indicate that irisin is associated with endothelial dysfunction and atherosclerosis in patients with type 2 diabetes. Our objective was to examine the relationship between irisin and urinary albumin excretion in patients with type 2 diabetes.
  
  
  METHODS
  100 newly diagnosed patients with type 2 diabetes and 100 healthy subjects were selected. Serum irisin levels were measured by ELISA, and urine albumin was measured by radioimmunoassay. High resolution ultrasound was used to measure brachial artery diameter at rest, after reactive hyperemia (flow-mediated arterial dilation, FMD) and after sublingual glyceryltrinitrate.
  
  
  RESULTS
  Patients with type 2 diabetes presented decreased irisin levels when compared to controls (14.12±3.93 versus 28.98±2.56ng/ml, P=0.015).Serum irisin levels in the microalbuminuric and macroalbuminuria subgroup were 9.89±1.56ng/ml and 5.67±1.89ng/ml, respectively, which were significantly lower than those in the normoalbuminuria (15.97±3.12ng/ml). In comparison to microalbuminuric subgroup, macroalbuminuria subgroup had lower levels of irisin. By dividing the distribution of serum irisin levels into quartiles, FMD was increased gradually with the increase of serum irisin levels (P<0.001). Multiple stepwise linear regression analysis showed that FMD (β=0.75, P=0.002), 2-hBG (β=-0.25, P=0.038) and UAE (β=-0.87, P=0.008) were significantly associated with irisin. Pearson's correlation analyses showed a negative correlation between irisin and logUAE (r=-0.57) and between FMD and logUAE (r=-0.47), and positive correlations between irisin and FMD (r=0.51).
  
  
  CONCLUSIONS
  Decreased plasma levels of irisin seem to be associated with UAE and FMD in patients with type 2 diabetes.
authors.affiliation: Department of Endocrinology, Dongguan People's Hospital, Dongguan 523000, Guangdong Province, P. R. China. Electronic address: hello_vanwang@sina.com.
authors.forename: Hao-hua
authors.initials: HH
authors.lastname: Wang
authors.affiliation: Department of Endocrinology, Dongguan People's Hospital, Dongguan 523000, Guangdong Province, P. R. China.
authors.forename: Xiu-wei
authors.initials: XW
authors.lastname: Zhang
authors.affiliation: Department of Endocrinology, Dongguan People's Hospital, Dongguan 523000, Guangdong Province, P. R. China.
authors.forename: Wei-kun
authors.initials: WK
authors.lastname: Chen
authors.affiliation: Department of Endocrinology, Dongguan People's Hospital, Dongguan 523000, Guangdong Province, P. R. China.
authors.forename: Qiu-xia
authors.initials: QX
authors.lastname: Huang
authors.affiliation: Department of Endocrinology, Dongguan People's Hospital, Dongguan 523000, Guangdong Province, P. R. China.
authors.forename: Qiao-qiong
authors.initials: QQ
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D000418:Albumins / Q000378:metabolism; D000419:Albuminuria / Q000097:blood / Q000150:complications / Q000453:epidemiology / Q000652:urine*; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology / Q000652:urine*; D005260:Female; D005353:Fibronectins / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D014463:Ultrasonography; D014664:Vasodilation
chemical_list: D000418:Albumins; C577593:FNDC5 protein, human; D005353:Fibronectins
keywords: Atherosclerosis; Endothelial function; Irisin; Type 2 diabetes; Urinary albumin excretion