Original Article Serum cystatin C in mouse models: a reliable and precise marker for renal function and superior to serum creatinine

Background: Serum creatinine (SCR) and blood urea nitrogen (BUN) determine the glomerular filtration rate (GFR) improperly in acute renal failure. Serum cystatin C (CYS) has the potential to be a more precise marker for GFR. The aim of this study was to compare the sensitivity of SCR, BUN and CYS with respect to the detection of acute renal failure in mice. Methods: In an ischaemia reperfusion (I/R) injury model, mice suffered 60-min left kidney ischaemia and right nephrectomy. In a nephrectomy model, mice were nephrec-tomized to a different extent: from unilateral (3/6Nx) to bi-lateral nephrectomy (BiNx). Blood samples were collected 2, 12 or 24 h post-op. Results: SCR,BUN and CYS increased significantly in the I/R-model in comparison to sham mice and 3/6Nx mice at 12 and 24 h post-op (SCR P = 0.009; BUN P < 0.001 and CYS P < 0.004). There were no significant differences in all three markers between 3/6Nx and sham-operated mice. In graded nephrectomy, BUN and CYS showed already significantly the loss of kidney in 4/6Nx mice 12 h post-op [BUN (mg/dl): sham 26.4 ± 3.5, 4/6Nx 52.3 ± 13.4, P < 0.01; CYS (mg/l): sham 0.08 ± 0.03, 4/6Nx 0.15