Influence of standard haemodialysis treatment on transcription of human serum- and glucocorticoid-inducible kinase SGK1 and taurine transporter TAUT in blood leukocytes.

BACKGROUND Standard haemodialysis (HD) rapidly alters osmolality and composition of extracellular fluid and, thus, challenges cell volume constancy. Cell volume-sensitive genes upregulated by osmotic cell shrinkage include those encoding for taurine transporter TAUT as well as for serum- and glucocorticoid-inducible kinase SGK1. METHODS Six HD patients were haemodialysed for 4 h with high-flux dialysers. Blood was drawn from the arterial section of the fistula immediately prior to start of HD and subsequently after 60, 120 and 240 min of HD treatment and, in addition, 120 min after HD treatment. Taurine plasma concentrations ([taurine]p) and erythrocytic taurine content ([taurine]e) were determined by high-performance liquid chromatography. SGK1 and TAUT transcript levels in leukocytes were quantified by real-time polymerase chain reaction. RESULTS The [taurine]p was significantly higher in HD patients before HD treatment when compared with healthy controls and it decreased significantly during 4 h of HD. The ratio of SGK1/GAPDH and of TAUT/GAPDH transcript levels increased significantly by 50% or 27%, respectively, during HD. CONCLUSIONS Standard HD treatment decreases plasma taurine concentration and upregulates leukocyte SGK1 and TAUT transcription. As SGK1 is a potent regulator of ion channels and transporters in nervous system, heart muscle and epithelial cells, the deranged regulation of SGK1 may contribute to acute side effects of HD treatment.