Urinary angiotensinogen accurately reflects intrarenal Renin-Angiotensin system activity.
BACKGROUND
We recently reported that immunoreactivity of intrarenal angiotensinogen (AGT) is significantly increased in IgA nephropathy patients. Meanwhile, we have developed direct enzyme-linked immunosorbent assays to measure plasma and urinary AGT (UAGT) in humans. This study was performed to test the hypothesis that UAGT levels are increased in chronic glomerulonephritis patients.


METHODS
We analyzed 100 urine samples from 70 chronic glomerulonephritis patients (26 from IgA nephropathy, 24 from purpura nephritis, 8 from lupus nephritis, 7 from focal segmental glomerulosclerosis, and 5 from non-IgA mesangial proliferative glomerulonephritis) and 30 normal control subjects.


RESULTS
UAGT-creatinine ratio (UAGT/UCre) was correlated positively with diastolic blood pressure (p = 0.0326), urinary albumin-creatinine ratio (p < 0.0001), urinary protein-creatinine ratio (p < 0.0001) and urinary occult blood (p = 0.0094). UAGT/UCre was significantly increased in chronic glomerulonephritis patients not treated with renin-angiotensin system (RAS) blockers compared with control subjects (p < 0.0001). Importantly, glomerulonephritis patients treated with RAS blockers had a marked attenuation of this augmentation (p = 0.0021).


CONCLUSIONS
These data indicate that UAGT are increased in chronic glomerulonephritis patients and treatment with RAS blockers suppressed UAGT. The efficacy of RAS blockade to reduce the intrarenal RAS activity can be confirmed by measurement of UAGT in chronic glomerulonephritis patients.
Urushihara
Maki
M
Department of Physiology, and Hypertension and Renal Center of Excellence, Tulane University Health Sciences Center, New Orleans, LA 70112-2699, USA.
Kondo
Shuji
S
Kagami
Shoji
S
Kobori
Hiroyuki
H
D000293:Adolescent; D000328:Adult; D000808:Angiotensinogen / Q000652:urine*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005921:Glomerulonephritis / Q000503:physiopathology / Q000652:urine*; D006801:Humans; D007668:Kidney / Q000503:physiopathology; D008297:Male; D012084:Renin-Angiotensin System / Q000502:physiology*; D015203:Reproducibility of Results; D055815:Young Adult
D000808:Angiotensinogen