ABSTRACT
Objective To compare the levels of indoxyl sulfate (IS) and p-cresyl sulfate (PCS), representative substances of serum protein-bound toxins,between patients undergoing peritoneal dialysis (PD) and healthy volunteers, and to explore the factors influencing the levels of serum IS and PCS. Methods Limosis vein blood (3 mL) were collected from 72 PD patients in Peritoneal Dialysis Center and 24 healthy voluteers in Physical Examination in Changzheng Hospital of Second Military Medical University from Feb. 2015 to Jul. 2015. The concentrations of serum total IS,total PCS,free IS and free PCS were detected by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ES--MS/MS) method. The relationship between IS, PCS and age, gender, small molecule toxins,adequacy of PD, residual renal function,nutritional status and C-reaction protein (CRP) in PD patients were analyzed by simple correlation andmultivariable linear regression analysis. Results The concentrations of serum total IS and total PCS in PD patients were significantly lower than those in healthy volunteers (P<0. 001). Compared with PD patients without residual renal function (RRF), the concentration of serum total IS was significantly lower in PD patients with RRF (P = 0. 001). Serum total IS was positively correlated with free IS (r=0. 719,P<0. 01) and dialysis duration (r=0. 306,P<0. 01),while tt was negatively correlated with residual renal Kt/V (r=-0. 372, P<0. 01),residual renal creatinine clearance rate (Ccr) (r=-0. 515,P<0. 01),and residual renal estimated glomerular filtration rate (eGFR) (r=-0. 495,P<0 01). Serum free IS was negatively correlated with residual renal Ccr (r=-0. 430, P〈0. 01) and residual renal eGFR (r= -0. 431,P〈0. 01). Serum total IS and free IS were not related to age,hemoglobin or CRP.conclusion serum level is negatively correlated with RRF. But not with age, hemoglobin or CRP, suggesting that proection of RRF is conducive to the removal of serum IS in parients undergoing PD.