title: Urinary angiotensinogen as a potential biomarker of intrarenal renin-angiotensin system activity in Chinese chronic kidney disease patients.
abstract: BACKGROUND
  Urinary angiotensinogen (AGT) mainly derives from the AGT produced in proximal tubular cells. Evidence exists that supports the correlation between urinary AGT and circulating AGT.
  
  
  OBJECTIVE
  To investigate the role of urinary AGT as a potential biomarker of intrarenal renin-angiotensin system activity in Chinese chronic kidney disease (CKD) patients.
  
  
  METHODS
  ELISA-based method used to quantify urinary AGT. Analyzed the relationship between urinary AGT and intrarenal angiotensin II (Ang II) activity in 128 CKD patients. ELISA was applied to measure the urinary and plasma renin activity, AGT, Ang II and aldosterone. Furthermore expression levels of intrarenal renin, AGT, Ang II and Ang II receptor were examined by immunohistochemistry staining (IHCS) in 72 CKD patients undergoing renal biopsy.
  
  
  RESULTS
  The logarithmic transformation Log(urinary AGT/UCre) levels showed a normal distribution. Therefore, Log(urinary AGT/UCre) levels were used for the analyses. Average urinary AGT was 2.02 ± 0.55 ng/(mg Cr). Hypertension, urinary protein, urinary Ang II and urinary type IV collagen (Col IV) positively correlated with urinary AGT. Estimated glomerular filtration rate (eGFR), urinary sodium and serum AGT negatively correlated with urinary AGT. Multiple regression analysis indicated that low serum AGT, high urinary protein, urinary Ang II and urinary Col IV correlated significantly with high urinary AGT.
  
  
  CONCLUSIONS
  We observed positive correlation between urinary AGT and positive IHCS area of AGT, Ang II and Ang II type 1 receptor in renal tissue. These data suggest that urinary AGT might be a potential biomarker of intrarenal Ang II activity in CKD patients.
authors.affiliation: Department of Urology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Ganhe Road 110, Shanghai, 200437, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Xu
authors.forename: B
authors.initials: B
authors.lastname: Xu
authors.forename: C
authors.initials: C
authors.lastname: Xu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000450:Aldosterone / Q000097:blood / Q000652:urine; D000804:Angiotensin II / Q000032:analysis* / Q000378:metabolism; D000808:Angiotensinogen / Q000032:analysis / Q000652:urine*; D044466:Asian People; D015415:Biomarkers / Q000652:urine; D002681:China; D024141:Collagen Type IV / Q000652:urine; D005260:Female; D006801:Humans; D006973:Hypertension / Q000652:urine*; D007668:Kidney / Q000737:chemistry; D008297:Male; D008875:Middle Aged; D011945:Receptors, Angiotensin / Q000032:analysis; D051436:Renal Insufficiency, Chronic / Q000652:urine*; D012083:Renin / Q000032:analysis* / Q000378:metabolism; D012084:Renin-Angiotensin System / Q000502:physiology*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D024141:Collagen Type IV; D011945:Receptors, Angiotensin; D000808:Angiotensinogen; D000804:Angiotensin II; D000450:Aldosterone; D012083:Renin