Urinary angiotensinogen reflects the activity of intrarenal renin―angiotensin system in patients with IgA nephropathy

• Published in: Nephrology, dialysis, transplantation Vol. 26; no. 1; pp. 170 - 177
• Main Authors: NISHIYAMA, Akira, KONISHI, Yoshio, KOBORI, Hiroyuki, IMANISHI, Masahito, OHASHI, Naro, MORIKAWA, Takashi, URUSHIHARA, Maki, MAEDA, Isseki, HAMADA, Masahiro, KISHIDA, Masatsugu, HITOMI, Hirofumi, SHIRAHASHI, Nobuo
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01-01-2011
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Angiotensinogen - urine; Biological and medical sciences; Biomarkers - urine; Blood Pressure; Case-Control Studies; Creatinine - urine; Emergency and intensive care: renal failure. Dialysis management; Enzyme-Linked Immunosorbent Assay; Female; Glomerular Filtration Rate; Glomerulonephritis; Glomerulonephritis, IGA - physiopathology; Glomerulonephritis, IGA - urine; Humans; Immunoenzyme Techniques; Intensive care medicine; Male; Medical sciences; Middle Aged; Nephrology. Urinary tract diseases; Nephropathies. Renovascular diseases. Renal failure; Original; Renin-Angiotensin System - physiology; Kidney disease; Human; Imidazole derivatives; Tetrazole derivatives; IgA; Urinary system disease; Valsartan; Hemodialysis; Peptide hormone; angiotensinogen; urinary biomarker; Extrarenal dialysis; Octapeptide; Renin angiotensin system; Nephropathy; IgA nephropathy; Biphenyl derivatives; Aminoacid; Renal failure; Antihypertensive agent; Sartan derivatives; Angiotensin antagonist; Valine derivatives; Angiotensin II
• ISSN: 0931-0509; 1460-2385
• DOI: 10.1093/ndt/gfq371

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.
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.
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.
These data indicate that urinary angiotensinogen is a powerful tool for determining intrarenal RAS status and associated renal derangement in patients with IgA nephropathy.