Effective Removal Of Protein-bound Uraemic Toxins By Different Blood Purification Strategies

[Objective]To study the effective of removal protein-bound uremic toxins in serum of maintenance hemodialysis patients with different blood purification strategies.[Method]One hundred and thirty-six MHD patients were selected,and after 4 weeks of wa shout period,then divided into 4 groups,randomly: low-flux hemodialysis(LFHD)group,high-flux hemodialysis(HFHD) group,hemodiafiltration(HDF) group and hemoperfusion combined with hemoperfusion(HP) group.Collected the serum before and after each treatment and the dialysate in LFHD,HFHD and HDF group at the same time.In addition,hemoperfusion apparatus in HP group were also collec ted.Using rotary evaporation to extract the protein-bound toxins in apparatus.At last determined the concentrations of hippuric acid(HA),p-cresyl sulphate(PCS), indoxyl sulfate(IS), 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid(CMPF) in these collected samples with high performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS) method.Calculated the cleanrance rate of these to xins, and determine the mass of the 4 kinds of toxins in dialysate and hemoperfusion apparatus so as to observation the effect on removal of protein-bound toxins with different blood purification strategies.We also measured the total and free concentrations of HA,PCS,IS and CMPF before and after hemodialysis in low-flux hemodialysis group, and calculate the protein binding rate of each toxins before and after dialysis.[Result]As for HA in serum, the concentrations of MHD patients were significantly decreased in each group(P<0.01), the reduction rate were(58.40±19.40)%,(62.74±18.39)%,(64.39±14.30)% and(58.97±14.13)% in LFHD,HFHD,HDF and HP group respectively. The reduction rate were no difference in LFHD,HFHD,HDF and HP group(P>0.05).As for PCS in serum, the concentrations of MHD patients were significantly decreased in each group(P<0.01), the reduction rate were(31.66±11.75)%,(31.62±19.87)%,(41.70±10.24)% and(45.37±15.39)% in LFHD,HFHD,HDF and HP group respectively.The reduction rate in HDF group and HD+HP group were significantly higher than that of LFHD group(P<0.01, P<0.01) and HFHD group(P<0.05, P<0.01).As for IS in serum, the concentrations of MHD patients were significantly decreased in each group(P<0.01), the reduction rate were(33.76±16.12)%,(37.83±21.24)%,(47.11±13.90)% and(48.62±16.31)% in LFHD,HFHD,HDF and HP group,respectively. The reduction rate in HDF group and HD+HP group were significantly higher than that of LFHD group(P<0.05,P<0.05) and HFHD group(P<0.05,P<0.05).As for CMPF in serum, the concentrations of MHD patients were decreased in HDF and HP group(P<0.05,P<0.01), the reduction rate were(-15.50±21.76)%,(-12.70±28.19)%,(8.46±4.63)% and(30.37±15.05)% in LFHD,HFHD,HDF and HP group, respectively.The reduction rate in HDF group and HD+HP group were significantly higher than that of LFHD group(P<0.01, P<0.01) and HFHD group(P<0.01, P<0.01).The reduction rate in HD+HP group was higher than HDF group(P<0.01).The total solute removal of HA were(115.75±82.74)mg,(127.60±73.66)mg,(146.39±80.57)mg and(110.88±60.83)mg in LFHD,HFHD,HDF and HP group,respectively.The total solute removal(TSR) of HA in HDF group was higher than LFHD group(P<0.05) and HD+HP group(P<0.01).The TSR of PCS were(28.75±9.96)mg,(31.40±20.50)mg,(81.09±39.65)mg and(74.12±32.60)mg in LFHD,HFHD, HDF and HD+HP group,respectively.The TSR removl of PCS in HDF group and HP group were significantly higher than LFHD group(P<0.01, P<0.01) and HFHD group(P<0.05 P<0.05).The TSR of IS were(29.38±19.50)mg,(33.93±13.63)mg,(79.85±38.60)mg and(70.08±31.39)mg in LFHD,HFHD, HDF and HP group,respectively.The TSR of IS in HDF group and HP group were significantly higher than LFHD group(P<0.01, P<0.01) and HFHD group(P<0.01, P<0.01).In LFHD and HFHD group,the concentration of CMPF in dialyate cannot detect,which were(3.67±1.59)mg and(8.44±6.58)mg in HDF and HD+HP group,respectively.The TSR of CMPF in HD+HP group was higher than HDF group(P<0.01).The total and free concentration of HA in LFHD group were(30.85±10.74) mg/L and(12.43±8.24) mg/L before dialysis respectively. And the protein binding rate of HA was(54.56±8.87)%. The total and free concentration of HA after dialysis were(13.31±11.78) mg/L and(6.29±3.68) mg/L,respectively.And the protein binding rate was(55.13±9.22)%. The total and free concentration of PCS were(28.51±16.61) mg/L and(0.82±0.60) mg/L before dialysis respectively. And the protein binding rate of was(95.86±2.87)%.The total and free concentrations of PCS after dialysis were(17.29±9.23) mg/L and(0.31±0.19) mg/L,respectively.And the protein binding rate was(95.73±3.15)%. The total and free concentration of IS were(30.33±15.00) mg/L and(1.54±0.98) mg/L before dialysis. And the protein binding rate was(95.56±1.59)%..The total and free concentrations of IS after dialysis were(19.78±10.95) mg/L and(0.35±0.22) mg/L, the protein binding rate was(95.16±1.68)%.Compared with other three kinds of toxins, CMPF is a highly protein-bound toxin.The total and free concentration before dialysis were(20.33±17) mg/L and(0.01±0.00) mg/L, the protein binding rate was(99.89±0.01)%.After dialysis the total and free concentration were(22.16±18.90) mg/L and(0.01±0.00) mg/L, the protein binding rate was(99.99±0.01)%.There was no difference in the protein binding rate between the four toxins before and after dialysis(P>0.05).[Conclusion](1)LFHD,HFHD,HDF and HP can remove part of the protein-bound toxins, but the removal effective were different.(2)The four strategies to remove low affinity to human serum albumin protein-bound toxin were no significant difference between each other, and close to small molecule toxins.(3)The four strategies to remove middle affinity to human serum albumin protein-bound toxins have significant difference between each other, HDF and HP were superior to HFHD and LFHD.(4)HFHD and LFHD were hardly to remove high affinity to human serum albumin protein-bound toxins,while HDF and HP can be partially removed, but the HP is the best.