The influence of proteinuria on tubular transport of Na+, K+, CL

Functional and structural damages of tubulointerstitium are caused by proteinuria. The aim of this study was to assess the influence of different proteinuria levels on Na+, K+, Cl- tubular transport. We examined 50 patients (24 males, 26 females), mean age 46.50 +/- 13.08 years, with mean creatinine clearance of 87.29 +/- 31.17 mL/min. They were separated in three groups, depending on proteinuria value. The first group with proteinuria less than 0.3 g/24 h included 19 persons (7 males, 12 females), mean age 45.12 +/- 13.28 years, with mean creatinine clearance of 94.27 +/- 34.70 mL/min. The second group of 18 patients (8 males, 10 females), mean age 45.39 +/- 12.64 years, had proteinuria of 0.3-3.0 g/24 h and mean creatinine clearance of 90.07 +/- 31.89 mL/min. The third group had proteinuria level higher than 3.0 g/24 h and mean creatinine clearance of 73.25 +/- 20.44 mL/min. It included 13 patients (9 males, 4 females), mean age 50.08 +/- 13.73 years. As a parameter of proteinuria influence on tubular transport of Na+, K+ and Cl-, fractional excretion of these electrolytes, was studied. Student's T test, Mann Whitney U test and c2 test were used for statistical analysis. No statistically significant influence of proteinuria was found on Na+, K+ and Cl tubular transport.