Evidence of taurine depletion and accumulation of cysteinesulfinic acid in chronic dialysis patients

Methionine, taurine and cysteinesulfinic acid (CSA) were determined by reversed-phase high-performance liquid chromatography (RP-HPLC) in plasma from ten patients treated with hemodialysis (HD) and eight patients treated with continuous ambulatory peritoneal dialysis (CAPD). The patients' data were compared with data obtained from ten healthy controls. Significant reductions in plasma taurine levels were observed in the HD patients (34 +/- 13 mu mol/liter, mean +/- SD) and the CAPD patients (47 +/- 12 mu mol/liter) compared to the controls (66 +/- 5 mu mol/liter), while the CSA levels were markedly higher in the HD patients (9.1 +/- 2.8 mu mol/liter) and the CAPD patients (9.1 +/- 2.4 mu mol/liter) than in the controls (0.79 +/- 0.15 mu mol/liter). A single HD treatment significantly reduced the plasma taurine and CSA concentrations (P < 0.01 and P < 0.001), respectively. The plasma methionine levels were normal in both patient groups. The finding of a low plasma taurine level and a large accumulation of CSA suggests that the metabolic conversion of CSA to taurine is impaired in uremic patients and this metabolic abnormality may cause taurine depletion.