Polymorphisms in mTOR and Calcineurin Signaling Pathways Are Associated With Long-Term Clinical Outcomes in Kidney Transplant Recipients

Monitoring of immunosuppressive drugs, such as calcineurin and mTOR inhibitors, is essential to avoid undesirable kidney transplant outcomes. Polymorphisms in pharmacokinetics-related genes have been associated with variability in blood levels of immunosuppressive drugs and adverse effects, but influence of pharmacodynamics-related genes remains to be elucidated. The influence of polymorphisms in genes of the mTOR and calcineurin signaling pathways on long-term clinical outcomes was investigated in Brazilian kidney transplant recipients within the 1-year post-transplant. Two-hundred and sixty-nine kidney transplant recipients were enrolled at a kidney transplant center in São Paulo city, Brazil, and treated with tacrolimus plus everolimus or mycophenolate sodium (clinical trial NCT01354301). Clinical and laboratory data, including renal function parameters and drug blood levels were recorded. Genomic DNA was extracted from blood samples. Polymorphisms in MTOR rs1057079 (c.4731G>A), rs1135172 (c.1437T>C), and rs1064261 (c.2997C>T); PPP3CA rs3730251 (c.249G>A); FKBP1A rs6033557 (n.259+24936T>C); FKBP2 rs2159370 (c.-2110G>T); and FOXP3 rs3761548 (c.-23+2882A>C) and rs2232365 (c.-22-902A>G) were analyzed by real-time PCR. Frequencies of gene polymorphisms did not differ among the treatment groups. Analysis of primary outcomes showed that patients carrying MTOR c.1437CC and FOXP3 c.-23+2882CC genotypes had higher serum creatinine than non-carriers (p < 0.05) at 1-year post-transplant. MTOR c.4731G allele (AG+GG genotype) was associated with increased risk for acute rejection (OR = 3.53, 95% CI = 1.09–11.48, p = 0.037). Moreover, 1-year cumulative incidence of rejection was higher in MTOR c.4731G allele carriers compared to AA genotype carriers (p = 0.027). Individually, analysis of secondary outcomes revealed that FKBP2 c.-2110GG genotype carriers had higher risk of leukopenia, FKBP1A n.259+24936C allele carriers had increased risk of constipation, and FOXP3 c.-22-902A or c.-23+2882A allele had higher risk of gastrointestinal disorders (p < 0.05). However, these results were not maintained in the multivariable analysis after p-value adjustment. In conclusion, variants in genes of mTOR and calcineurin pathways are associated with long-term impaired renal function, increased risk of acute rejection, and, individually, with adverse events in Brazilian kidney transplant recipients

Polymorphisms in pharmacodynamics-related genes of tacrolimus and everolimus and their relationship with the response to immunosuppressant treatment, in kidney transplant recipients.

O monitoramento de imunossupressores, como os inibidores de calcineurina ou de mTOR, é essencial para evitar desfechos clínicos desfavoráveis, em receptores de transplante renal. Polimorfismos em genes envolvidos na farmacocinética têm sido associados com variabilidade na resposta a imunossupressores, porém o papel de polimorfismos em genes envolvidos na farmacodinâmica é pouco conhecido. O objetivo deste estudo foi investigar a influência de polimorfismos de MTOR, PPP3CA, FKBP1A, FKBP2 e FOXP3, genes envolvidos na farmacodinâmica de imunossupressores, sobre a resposta clínica a tacrolimo e everolimo, em receptores de transplante renal. Foram incluídos 269 pacientes do ensaio clínico original (NCT01354301), realizado no Hospital do Rim e Hipertensão da UNIFESP, e randomizados em três esquemas imunossupressores: tacrolimo 0,05 mg/kg/dia com everolimo 1,5 mg/dia (TAC5/EVR); tacrolimo 0,1 mg/kg/dia com everolimo 1,5 mg/dia (TAC10/EVR); e tacrolimo 0,1 mg/kg/dia com micofenolato de sódio (TAC10/MFS). Foram coletados dados clínicos e laboratoriais, tais como o monitoramento de imunossupressores e desfechos de eficácia de segurança. Os polimorfismos nos genes MTOR (c.4731G>A, c.1437T>C, c.2997C>T); PPP3CA (c.249G>A); FKBP1A (n.259+243936T>C); FBKP2 (c.-2110G>T) e FOXP3 (c.-23+2882A>C, c.-22-902A>G) foram analisados por PCR em tempo real. As frequências alélicas dos polimorfismos estudados foram similares às da população global do projeto 1000genomes. O tratamento com everolimo e tacrolimo em maior dose (TAC10/EVR) foi associado com menor taxa de filtração glomerular estimada (TFGe) e maior creatinina sérica. Enquanto que o tratamento com tacrolimo e micofenolato de sódio (TAC10/MFS) foi associado com maior número de episódios de infecção por citomegalovirus, no 1° ano pós-transplante. Com relação aos desfechos de eficácia, os portadores do genótipo CC de MTOR c.1437T>C e FOXP3 c-23+2882A>C apresentaram maiores concentrações de creatinina sérica, no 12° mês (pC foi associado com maior probabilidade de creatinina sérica aumentada (OR=1,75; IC95%=1,07-2,86; p=0,025). Os resultados da análise de regressão logística mostraram que o alelo MTOR c.4731G (genótipos AG+GG) foi associado com maior risco de rejeição aguda (OR=3,37; IC95%=1,10-10,30; p=0,033). Os portadores do alelo c.4731G apresentaram maior incidência cumulativa de episódios de rejeição, no 1° ano pós-transplante. Com relação aos desfechos de segurança, a variante FKBP2 c.-2110G>T (genótipo GG) foi associada com maior risco de leucopenia (OR=7,10; IC95%=1,81-27,87; p=0,025). O polimorfismo FKBP1A n.259+24936T>C (alelo C) foi associado com maior risco de constipação (OR=2,52; IC95%=1,13 - 5,61; p=0,024), enquanto que os polimorfismos FOXP3 c.-22-902A>G (alelo A) e c.-23+2882A>C (alelo A) foram associados, respectivamente, com maior risco de epigastralgia (OR=2,15; IC95%=1,01-4,56; p=0,047) e náuseas e/ou vômitos (OR=2,38; IC95%=1,05-5,38; p=0,038). O risco de apresentar dislipidemia foi maior nos portadores dos genótipos FKBP2 c.-21110GG (OR=1,92; IC95%=1,01-3,69; p=0,049) e FOXP3 c.-22-902GG (OR=2,06; IC95%=1,08-3,92; p=0,028). Em conclusão, os polimorfismos de genes MTOR, FKBP1A, FKBP2 e FOXP3 influenciam na função renal do enxerto e estão associados com risco de rejeição aguda e de eventos adversos, em receptores de transplante renal.The monitoring of immunosuppressive drugs, such as calcineurin and mTOR inhibitors, is essential to avoid undesirable kidney transplant outcomes. Polymorphisms in pharmacokinetics-related genes have been associated with variability in the response to immunosuppressive drugs, but the role of polymorphisms in pharmacodynamics-related genes is little known. The aim of this work was to investigate the influence of polymorphisms in MTOR, PPP3CA, FKBP1A, FKBP2 and FOXP3, genes involved in the pharmacodynamics of immunosuppressive drugs, on the clinical response to tacrolimus and everolimus in kidney transplant recipients. Two-hundred seventy-five kidney transplant recipients were included in this study, among the enrolled in the original clinical trial (NCT01354301) carried out at the Hospital do Rim e Hipertensão/UNIFESP, and randomized in three immunosuppressive treatments: tacrolimus 0.05 mg/kg/day with everolimus 1.5 mg/day (TAC5/EVR); tacrolimus 0.1 mg/kg/day with everolimus 1.5 mg/day (TAC10/EVR); and tacrolimus 0.1 mg/kg/day with sodium mycophenolate (TAC10/MFS). Clinical and laboratory data, including immunosuppressive drug monitoring, efficacy and safety outcomes, were recorded. Polymorphisms on the MTOR (c.4731G>A, c.1437T>C, c.2997C>T); PPP3CA (c.249G>A); FKBP1A (n.259+243936T>C); FBKP2 (c.-2110G>T) and FOXP3 (c.-23+2882A>C, c.-22-902A>G) genes were analyzed by real-time PCR. Allelic frequencies of the studied polymorphisms were similar to those of the global population reported by the 1000genomes project. Treatment with everolimus and high-dose tacrolimus (TAC10/EVR) was associated with lower estimated glomerular filtration rate (eGFR) and higher serum creatinine. Meanwhile treatment with tacrolimus and sodium mycophenolate (TAC10/MFS) was associated with higher number of cytomegalovirus infections, at 1-year post-transplantation. With regard to the kidney efficacy outcomes, the carriers of the CC genotype of MTOR c.1437T>C and FOXP3 c.-23+2882A>C had higher serum creatinine, at month 12 (pC polymorphism was associated with high likelihood of increased serum creatinine (OR=1.75, 95%IC=1.07-2.86, p=0.025). The results of the logistic regression analysis showed that the allele MTOR c.4731G (AG+GG genotypes) was associated with higher risk of acute rejection (OR=3.37, 95%IC=1.10-10.30, p=0.033). The carriers of the c.4731G allele showed higher cumulative incidence of acute rejection episodes at 1-year post-transplantation. With regard to kidney safety outcomes, the FKBP2 c.-2110G>T variant (GG genotype) was associated with higher risk of leucopenia (OR=7.10, 95%IC=1.81-27.87, p=0.025). The FKBP1A n.259+24936T>C (C allele) polymorphism was associated with higher risk of constipation (OR=2.52, 95%IC=1.13-5.61, p=0.024), whilst FOXP3 c.-22 902A>G (A allele) and c.-23+2882A>C (A allele) were associated, respectively, with higher risk of epigastric pain (OR=2.15, 95%IC=1.01-4.56, p=0.047) and nausea and/or vomiting (OR=2.38, 95%IC=1.05-5.38, p=0.038). The risk of developing dyslipidemia was higher in carriers of the genotypes FKBP2 c.-21110GG (OR=1.92, 95%CI=1.01-3.69, p=0.049) and FOXP3 c.-22-902GG (OR=2.06, 95%CI=1.08-3.92, p=0.028). In conclusion, the polymorphisms in the MTOR, FKBP1A, FKBP2 and FOXP3 genes influence renal graft function and are associated with risk of acute rejection and adverse events in renal transplant recipients