The relationship between renal volume, serum and urine uromodulin levels and existing renal function in living kidney donors

Uromodulin is known as an indicator of nephron mass and tubular function. The aim of this study was to investigate the relationship between serum uromodulin (Sumod), urine uromodulin (Uumod) and remaining kidney volume and function in living kidney donors (LKD). One hundred LKD (Mean age 52.46±10.38, 65 women) were included in the study. Kidney volumes were assessed by preoperative abdominal computed tomography and by magnetic resonance imaging at the last clinic visit. Uromodulin levels were measured in blood and urine by uromodulin human ELISA kit (Brno, Czech Republic; RD191163200R). Average follow-up was 63.23±56.82 months. 16 donors had chronic kidney disease (CKD) during the follow up. There was a correlation between Sumod and glomerular filtration rate (GFR) (r=0.29, P=0.006), creatinine (r=-0.25, P=0.02) and age (r=-0.36, P<0.001). Sumod levels of 16 patients with CKD was lower than those without CKD (78.12±34.19 vs. 94.03±32.55 ng/ml, P=0.047). A strong correlation between Uumod and GFR was found in patients with CKD (r=0.64, P=0.007). Uumod level changed in parallel with the follow-up period (r=0.28, P=0.006). A negative correlation between Uumod and proteinuria difference was demonstrated (r=-0.32, P=0.002). The remaining kidney was found to be enlarged by 22%. The increase in volume correlated with GFR (r=0.34, P=0.001) and follow-up time (r=0.37, P<0.001). There was no relationship among Sumod, Uumod and remaining kidney volume. Kidney function in LKD were associated with Sumod, Uumod and remaining kidney volume. Uumod was a better indicator of kidney function in donors who developed CKD. Key words: Uromodulin, Tamm-Horsfall protein, kidney volume, living kidney donor, renal transplantation