Clinical relevance of urinary angiotensinogen and renin as potential biomarkers in patients with overt proteinuria

Comparison of intrarenal renin‐angiotensin system activity in diabetic versus non‐diabetic patients with overt proteinuria

“…Recently, research has focused on local RAS activity, including intrarenal RAS activity . uAGT and uRenin are considered as adequate markers of intrarenal RAS activity, and our recent study demonstrates that uRenin is a relevant marker of intrarenal RAS activity, especially in overt proteinuria . Also, Heuvel et al .…”

“…3,24 Recently, research has focused on local RAS activity, including intrarenal RAS activity. [24][25][26] uAGT and uRenin are considered as adequate markers of intrarenal RAS activity, [13][14][15] and our recent study demonstrates that uRenin is a relevant marker of intrarenal RAS activity, especially in overt proteinuria. 15 Also, Heuvel et al revealed that renal RAS activation is reflected by increased uRenin levels in patients with diabetes and decreased uRenin levels following RAS blockade.…”

“…The plasma and urinary renin activities were assessed using renin radioimmunoassay beads (TFB, Tokyo, Japan) and a Cobra-II Gamma Counter (Packard Bioscience), according to the manufacturers' protocols, as previously reported. 15 Briefly, for the urine samples, the detection limit of the enzymatic-kinetic assay was 0.10 ng angiotensin I/mL/h, and the angiotensin I-generating activities were converted to renin concentrations based on a correspondence of 1 ng angiotensin I/mL/h to 2.6 pg human renin/mL. 15,23 The urine samples were concentrated five fold with Amicon Ultra-10 centrifugal filter devices (Millipore, Cork, Ireland), before the samples were applied to the assay.…”

“…Several previous studies have shown the presence of RAS components in the kidney and demonstrated that urinary angiotensinogen (uAGT) and urinary renin (uRenin) directly reflect the activity of intrarenal RAS. [13][14][15] Based on the evidence that activation of RAS is a key pathophysiologic mechanism, and the benefit of RAS blockers from the early phase before onset of overt proteinuria in DN, we hypothesized that intrarenal RAS is more activated in DN compared to NDN in patients with overt proteinuria. 16,17 To date, however, there have been no studies comparing intrarenal RAS activity quantitatively between DN and NDN, especially in patients with overt proteinuria.…”

The Relationship Between Proteinuria and Urinary Angiotensinogen Levels in Patients with Nephrotic Syndrome

“…Although the authors indicated that AGT is produced even by kidney, this correlation between serum and urinary AGT levels in the presence of nephrotic-range proteinuria was interpreted in favor of glomerular injury. Therefore AGT could be non-specifically excreted in the urine as albumin, since those two molecules had similar molecular weights (39). However, a similar study with IgAN patients, reporting a positive correlation between urinary AGT levels and proteinuria, showed that AGT mRNA level in renal tissue was high in harmony with urinary AGT.…”