title: Urinary angiotensinogen reflects the activity of intrarenal renin-angiotensin system in patients with IgA nephropathy.
abstract: BACKGROUND
  A potential contribution of local activation of the renin-angiotensin system (RAS) to the pathogenesis of renal injury has been indicated by evidence for blood pressure-independent renoprotective effects of angiotensin II (AngII) receptor blockers (ARBs). The present study was performed to test the hypothesis that urinary angiotensinogen provides a specific index of intrarenal RAS status in patients with immunoglobulin A (IgA) nephropathy.
  
  
  METHODS
  This paper is a survey of urine specimens from three groups: healthy volunteers, patients with IgA nephropathy and patients with minor glomerular abnormality (MGA). Patients with hypertension, diabetes, reduced glomerular filtration rate and/or who were under any medication were excluded from this study. Urinary angiotensinogen levels were measured by a sandwich enzyme-linked immunosorbent assay system.
  
  
  RESULTS
  Urinary angiotensinogen levels were not different between healthy volunteers and patients with MGA. However, urinary angiotensinogen levels, renal tissue angiotensinogen expression and AngII immunoreactivity were significantly higher in patients with IgA nephropathy than in patients with MGA. Baseline urinary angiotensinogen levels were positively correlated with renal angiotensinogen gene expression and AngII immunoreactivity but not with plasma renin activity or the urinary protein excretion rate. In patients with IgA nephropathy, treatment with an ARB, valsartan (40 mg/day), significantly increased renal plasma flow and decreased filtration fraction, which were associated with reductions in urinary angiotensinogen levels.
  
  
  CONCLUSIONS
  These data indicate that urinary angiotensinogen is a powerful tool for determining intrarenal RAS status and associated renal derangement in patients with IgA nephropathy.
authors.affiliation: Department of Pharmacology, Kagawa University Medical School, Kagawa, Japan. akira@kms.ac.jp
authors.forename: Akira
authors.initials: A
authors.lastname: Nishiyama
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Konishi
authors.forename: Naro
authors.initials: N
authors.lastname: Ohashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Morikawa
authors.forename: Maki
authors.initials: M
authors.lastname: Urushihara
authors.forename: Isseki
authors.initials: I
authors.lastname: Maeda
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hamada
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Kishida
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Hitomi
authors.forename: Nobuo
authors.initials: N
authors.lastname: Shirahashi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kobori
authors.forename: Masahito
authors.initials: M
authors.lastname: Imanishi
mesh_terms: D000808:Angiotensinogen / Q000652:urine*; D015415:Biomarkers / Q000652:urine*; D001794:Blood Pressure; D016022:Case-Control Studies; D003404:Creatinine / Q000652:urine; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005919:Glomerular Filtration Rate; D005922:Glomerulonephritis, IGA / Q000503:physiopathology* / Q000652:urine*; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D012084:Renin-Angiotensin System / Q000502:physiology*
chemical_list: D015415:Biomarkers; D000808:Angiotensinogen; D003404:Creatinine