Purpose: Genetic polymorphisms have been associated with variation in the metabolism of tacrolimus (TAC) in kidney transplant patients. This study is aimed at assessing the impact of allelic variants of CYP3A5 and PPARA genes on the pharmacokinetics (PK) of TAC in Brazilian kidney transplant recipients in the first-year post-transplant.
Methods: A total of 127 patients were included for genetic evaluation. Genomic DNA was isolated from peripheral blood and real-time PCR was used to analyze the main polymorphisms described for the genes CYP3A5 (rs776746; C > G) and PPARA (rs4823613; A > G and rs4253728; G > A).
Results: CYP3A5 expressors showed a lower Co/dose ratio than non-expressors, with the median values of this parameter <1.01 ng/mL/mg in the first group at all evaluated times. Additionally, PPARA variant homozygotes had a lower Co/D ratio than wild allele carriers in the 12-month post-transplant period, with a median value of 0.65 ng/mL/mg. In the CYP3A5 expressers, the presence of the variant homozygous genotype PPARA was associated with a lower value of Co/D compared with the other genotypic groups at month 12.
Conclusion: In the population under study, polymorphisms on CYP3A5 and PPARA were identified as determining and independent factors associated with the reduction of Co/D of TAC. Thus, the genotyping of these genetic variants may be a useful tool for the individualized prescription of TAC in kidney transplant patients.
Keywords: CYP3A5; Co/D ratio; Kidney transplantation; PPARA; Pharmacokinetics; Tacrolimus.