Effect Of CYP3A5,CYP3A4 And MDR1 Gene Polymorphism On Tacrolimus Metabolism After Pediatric Liver Transplantation

Objective:To explore the blood concentration characteristics of tacrolimus after pediatric liver transplantation;to analyze the effect of CYP3A5*3（rs776746）gene on tacrolimus metabolism in this population;to analyze the effect of MDR1 3435C>T（rs1045642）gene on tacrolimus metabolism after transplantation in this population;to analysis of the effect of CYP3A4*18B（rs2242480）gene on the post-operative tacrolimus metabolism in this population;provide a reliable theoretical basis and early research basis for future precise medication.Method:1.According to the inclusion and exclusion criteria,select the children with liver transplantation in Tianjin First Central Hospital from June 2016 to June 2019;collect blood samples of liver transplant recipients and donors,and test the recipients and donors CYP3A5*3（rs776746）,MDR1 3435C>T（rs1045642）,CYP3A4*18B（rs2242480）genes by Sanger sequencing;chemiluminescent microparticle immunoassay（CMIA）was used to monitor patients’postoperative tacrolimus concentration（C₀）;patients were collected demographic information,daily dose of tacrolimus,C₀and physiological and biochemical information of patients within 3months after surgery;study the postoperative tacrolimus C₀characteristics,gene distribution of recipients and donors CYP3A5,MDR1,CYP3A4.2.The effect of CYP3A5*3（rs776746）gene on tacrolimus metabolism after pediatric liver transplantation:group patients based on CYP3A5 genotype;collect the daily dose and C₀of tacrolimus administered within 3 months after surgery and weight（WT）;according to the postoperative time,the C₀/D of patients were divided into four groups:week 1,week 2,week 3,and≥4 weeks;the C₀/D of 4 groups of patients with different genotypes were compared,and analysis the effect of CYP3A5gene for patients after the operation on tacrolimus metabolism,P<0.05 was considered statistically significant.3.The effect of MDR1 3435C>T（rs1045642）gene on tacrolimus metabolism after pediatric liver transplantation:the recipient/donor is divided into recipient/donor total slow metabolism（GG/GG）,recipient fast metabolism/donor slow metabolism（AG/GG）,recipient slow metabolism/donor fast metabolism（GG/AG）,recipient/donor fast metabolism（AA/AA,AA/AG,AG/AA,AG/AG）according to the CYP3A5 gene,denoted as R/D-S,R-F/D-S,R-S/D-F,R/D-F;collect the patient’s daily dose of tacrolimus,C₀and body weight（WT）within 3 months after the operation;Postoperative C₀/D was divided into four groups according to the postoperative time:week 1,week 2,week 3,and≥4 weeks;compare the differences of C₀/D in patients with different genotypes,and analyze the effect of MDR1 gene on tacrolimus metabolism in patients after treatment.P<0.05 was considered statistically significant.4.The effect of CYP3A4*18B（rs2242480）gene on tacrolimus metabolism after pediatric liver transplantation:collect the daily dose and C₀of tacrolimus administered within 3 months after surgery and weight（WT）;according to the postoperative time,the C₀/D of patients were divided into four groups:week 1,week2,week 3,and≥4 weeks;the C₀/D of 4 groups of patients with different genotypes were compared,and analysis the effect of CYP3A4 gene for patients after the operation on tacrolimus metabolism,P<0.05 was considered statistically significant.Results:1.This study collected a total of 180 subjects related to pediatric liver transplant recipients and donors.There was no significant difference in C₀value at different time periods after the operation,and the overall trend increased first and then decreased.There was a significant difference in C₀/D at different time periods after the operation（P<0.05）,the average C₀/D of the patients was the highest at the first week,the average at the second week was less than the first week,the average at the third week was less than the second week,4 weeks and later was the smallest.180subjects were tested for CYP3A5*3（rs776746）,CYP3A4*18B（rs2242480）,MDR13435C>T（rs1045642）,the frequency of the recipient（donor）CYP3A5 alleles G and A were 67.78%（73.89%）,32.22%（26.11%）.The frequency of CYP3A4 alleles G and A in recipients（donors）was 73.89%（72.78%）and 26.11%（27.22%）,respectively.The frequency of MDR1 allele C and T in the recipient（donor）was62.78%（57.78）and 37.22%（42.22%）.2.The CYP3A5 gene of the recipient and donor will affect the metabolism of tacrolimus after operation.Among the three genotypes of GG,AG,and AA,the metabolic capacity of the patients will increase in turn.In the early postoperative period,the recipients of the three genotypes showed significant differences between the two weeks（P<0.05）,and their C₀/D values were:GG>AG>AA.The CYP3A5gene of donors had significant differences in C0/D values between GG and AG patients at 1 week,2 weeks,3 weeks,and≥4 weeks after operation（P<0.05）.There were significant differences between the R/D-S group and the R/D-F group at the 1st,2nd,and 3rd postoperative days（P<0.05）;There were significant difference between the R-S/D-F group and the R/D-F group at the 1st and 2nd week postoperatively（P<0.05）;R-F/D--S group and R/D-F group at 1 week after operation had significant difference（P<0.05）;R-F/D-S group and R/D-S at 2 weeks after operation,≥4 weeks after operation between the R-S/D-F and the R/D-S group≥4 weeks after operation had significant differences in C₀/D values（P<0.05）.3.The MDR1 genotype of the recipient will affect the metabolism of tacrolimus after operation.The C₀/D of CT-type patients was significantly higher than that of CC-type patients at 3 weeks after surgery（P=0.0087）.The R/D-S subgroup analysis results showed that the C₀/D value of patients with CC type at week 2 was significantly lower than that of patients with CT type（P<0.05）,and showed the same trend at week 3 and was close to significance.In the R/D-F subgroup,the significant difference was observed between the second and third weeks（P<0.05）.4.The CYP3A4 gene of the recipient and donor will affect the metabolism of tacrolimus after operation.Among the three genotypes of GG,AG,and AA,the metabolic capacity will increase in turn.At 1 and 2 weeks after surgery,the C₀/D values of recipients with GG type and those with AG and AA type were significantly different（P<0.05）.The C₀/D value of GG patients was significantly higher than that of AG and AA patients（P<0.05）.There was a statistically significant difference between AA and AG patients in the first week after surgery（P<0.05）.The CYP3A4gene of donors was significantly higher than that of patients with GG type C0/D in the four time periods during the first,second,third and≥4 weeks after operation（P<0.05）.Conclusion:1.After operation in children with liver transplantation,the C₀/D value gradually decreases with the increase of postoperative time,which indicates that the patient’s metabolic capacity for tacrolimus gradually increases.This is basically consistent with the recovery of liver function and the development of physiological functions in children with liver transplantation.2.Recipients and donors CYP3A5 will affect the metabolism of tacrolimus.Among them,GG type is slow metabolism type,AG and AA are fast metabolism type,AA type patients have the fastest metabolism.In the early postoperative period,the transplanted liver is dysfunction,the recipient CYP3A5 gene plays an important role in tacrolimus metabolism,the recipient AA homozygous patients C₀/D compared with other patients there is twice the gap.These results are basically consistent with other existing studies.The CYP3A5 gene polymorphism in recipients and donors is an important reason for the individual differences in tacrolimus metabolism in patients.3.The recipient MDR1 genotype has a certain effect on the metabolism of tacrolimus in early postoperative pediatric liver transplantation patients.CC genotype patients have a stronger metabolic capacity for tacrolimus than CT and TT patients.However,CYP3A5 has a greater weighting effect on tacrolimus metabolism,and it is easy to mask the effect of MDR1 gene.For the CYP3A5 R/D-F group,the baseline C0/D value was lower,and the effect of MDR1 gene on the C₀/D value of the patients was more obvious,which reflected the intestinal MDR1 of recipients of R/D-F group has an obvious effect of tacrolimus metabolism.The clinical need to pay attention to the recipient/donor full fast metabolism（AA/AA,AA/AG,AG/AA,AG/AG）population,consider the influence of MDR1 gene,adjust the dosage regimen reasonably,and avoid the occurrence of adverse events.4.Recipient and donor CYP3A4 will affect the metabolism of tacrolimus by the patient.Hepatic dysfunction will occur in the first and second weeks after the operation,and the recipient CYP3A4 will play a relatively large role at this time;The donor liver function is restored,and the donor CYP3A4 still has an effect on the long-term tacrolimus metabolism.But in general,the CYP3A4 gene in the early postoperative recipients is the main factor affecting the metabolic capacity of tacrolimus.Because the recipient’s CYP3A4 gene is mainly expressed in the small intestine of the patient,the intestinal function of the patient is important for the metabolism of tacrolimus.