title: Urinary angiotensinogen is a marker for tubular injuries in patients with type 2 diabetes.
abstract: OBJECTIVE
  Urinary angiotensinogen has been reported as a marker for the activation of intrarenal renin-angiotensin system (RAS) in various kidney diseases. To investigate the importance of urinary angiotensinogen in diabetic nephropathy, we compared the urinary levels of angiotensinogen, albumin, and α1-microglobulin.
  
  
  METHODS
  Japanese patients with type 2 diabetes at various stages of nephropathy (n=85) were enrolled, and we measured albumin/creatinine ratio (ACR) and urinary excretion of angiotensinogen and α1-microglobulin. We also compared the clinical data of the patients treated with or without angiotensin II receptor blockers or angiotensin-converting enzyme inhibitors (RAS inhibitors [+], n=51; RAS inhibitors [-], n=34).
  
  
  RESULTS
  Urinary angiotensinogen levels positively correlated with ACR (r=0.367, P=3.84×10(-4)) and urinary α1-microglobulin (r=0.734, P=1.32 × 10(-15)), while they negatively correlated with estimated glomerular filtration ratio (eGFR) (r=-0.350, P=1.02 × 10(-3)) and high-density lipoprotein cholesterol (r=-0.216, P=0.049). Multiple regression analysis was carried out to predict urinary angiotensinogen levels by employing eGFR, ACR, and urinary α1-microglobulin as independent variables; only urinary α1-microglobulin entered the regression equation at a significant level. Although ACR was higher in the RAS inhibitors (+) group, urinary α1-microglobulin and angiotensinogen did not show significant increase in the RAS inhibitors (+) group.
  
  
  CONCLUSIONS
  Urinary angiotensinogen is well correlated with urinary α1-microglobulin and reflected the tubular injuries which may be associated with the intrarenal RAS activation in patients with type 2 diabetes.
authors.affiliation: Department of Medicine and Clinical Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Terami
authors.forename: Jun
authors.initials: J
authors.lastname: Wada
authors.forename: Kentaro
authors.initials: K
authors.lastname: Inoue
authors.forename: Atsuko
authors.initials: A
authors.lastname: Nakatsuka
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ogawa
authors.forename: Sanae
authors.initials: S
authors.lastname: Teshigawara
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Murakami
authors.forename: Akihiro
authors.initials: A
authors.lastname: Katayama
authors.forename: Jun
authors.initials: J
authors.lastname: Eguchi
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Makino
keywords: albumin; angiotensinogen; diabetic nephropathy; renin–angiotensin system; urinary biomarkers; α1-microglobulin