Influencing Factors And Population Pharmacokinetics Of Cyclosporine In Children With Aplastic Anemia

Objective:Taking the patients with aplastic anemia as the research object,the influencing factors of blood concentration of cyclosporine?CsA?in patients were explored,and the gene polymorphisms of drug metabolizing enzymes?CYP3A4,CYP3A5,CYP3AP1?,transporter?ABCB1?and its upstream regulators?PXR,POR and FOXP3?which maybe affect the blood concentration of cyclosporine were investigated,and the risk factors for abnormal changes blood concentration of CsA were clarified.To establish a population pharmacokinetic?PPK?model for children and adults,and to compare the differences of pharmacokinetic parameters among different groups,so as to provide reference for rational drug use in clinic.Methods:Patients with aplastic anemia who took CsA and regularly monitored their blood concentration were collected from Shengjing Hospital Affiliated to China Medical University.The serum concentration of CsA in patients with aplasti anemia was determined by enzymatic amplification immunoassay and divided in to three groups:high serum concentration group,normal serum concentration group and low serum concentration group.Nonlinear mixed effect model?NON-MEM?was used to establish the PPK model of children and adults respectively.PK model was used to investigate the effects of demographic information,dosage,blood routine,blood biochemistry and combination of drugs on CSA blood concentration and pharmacokinetic parameters.The final model was validated by Bootstrap method.DNA was extracted by blood DNA extraction kit,and polymerase chain reaction-restriction fragment length polymorphism?PCR-RFLP?and matrix-assisted laser lysis were used.MALDI-TOF MS technique was used to genotype the target gene loci in some subjects;the distribution frequency of the above SNP loci in patients with aplastic anemia was investigated,and the correlation between the above SNP loci and CSA blood concentration was analyzed;the above data were analyzed by chisquare test,One-Way ANOVA variance analysis and multiple linear regression analysis.Results:The influencing factors of serum CsA co ncentration in 192 children with aplastic anemia were studied.The influence of age and combined use of stanozolol on serum CsA concentration in children with aplastic anemia was statistically significant?P<0.05?,but there was no significant difference in gender,combined use of stanozolol,blood routine and liver and kidney function indexes?P>0.05?.The allele frequencies of CYP3A4?rs2242480?,CYP3A5?rs776746?,CYP3-AP1?rs217780?,ABCB1?rs1128503,rs2032582,rs1045642,rs28373093,rs77870-82?,PXR?rs3814055,rs2276707,rs6785049?,POR?rs1057868,rs2868177?,FO-XP3?rs3761548?were 25.52%,28.65%,5.73%,36.98%,36.48%,47.40%,respectively.41.15%,28.13%,46.87%,44.79%,41.15%,44.27%,17.71%.The standardized blood concentration of CYP3A5?rs776746?homozygous mutant?TT?was lower than that of wild type?CC?and heterozygous mutant?CT??P<0.05?.There was no significant difference in the standardized blood concentration of CYP3A4,CYP3AP1,ABCB1,PXR,POR and FOXP3 genotypes in children with aplastic anemia?P>0.05?.The PPK model formula for children with aplastic anemia was CL/F=73.5?T-AMT/135?^0.65?AST/24?^-0.3?CREA/40?^-0.24?0.09?^{T BIL/10},V/F=6870?TAMT/135?^0.89.The PPK model formula of adult aplastic anemia patients was CL/F=48.9?TAMT/193?^0.49,V/F=2790?TAMT/193?^-0.71.Bootstrap method shows that the model is stable and reliable,external validation shows that the final model has good prediction ability.Conclusion:This study found that age and combined use of stanozolol can affect the serum concentration of CsA in children with aplastic anemia.Therefore,the dosage should be strictly controlled when combined use of CsA and stanozolol in children with aplastic anemia in order to avoid adverse reactions.The gene polymorphism of CYP3A5,a drug metabolizing enzyme of CsA,has a significant effect on the blood concentration of children with aplastic anemia.The blood concentration of TT children with CYP3A5 gene mutation is significantly lower than that of CC and CT children.This difference has clinical application value for the precise treatment of CsA.There are significant differences between adult and child aplastic anemia patients in PPK model:serum creatinine,total bilirubin level and glutamic oxaloacetic transaminase only have significant effects on clearance rate of children with aplastic anemia,but have no effect on adults.Therefore,children and adults with aplastic anemia should individually adjust the dosage after taking CsA to improve the effect of drug treatment.