Influence of IL-18 and IL-10 Polymorphisms on Tacrolimus Elimination in Chinese Lung Transplant Patients

Genotype-Guided Model for Prediction of Tacrolimus Initial Dosing After Lung Transplantation

The determination of the appropriate initial dose for tacrolimus is crucial in achieving the target concentration promptly and avoiding adverse effects and poor prognosis. However, the trial-and-error approach is still common practice. This study aimed to establish a prediction model for an initial dosing algorithm of tacrolimus in patients receiving a lung transplant. A total of 210 lung transplant recipients were enrolled, and 26 single nucleotide polymorphisms (SNP) from 18 genes that could potentially affect tacrolimus pharmacokinetics were genotyped. Associations between SNPs and tacrolimus concentration/dose ratio were analyzed. SNPs that remained significant in pharmacogenomic analysis were further combined with clinical factors to construct a prediction model for tacrolimus initial dose. The dose needed to reach steady state tacrolimus concentrations and achieve the target range was used to validate model prediction efficiency. Our final model consisted of 7 predictors-CYP3A5 rs776746, SLCO1B3 rs4149117, SLC2A2 rs1499821, NFATc4 rs1955915, alanine aminotransferase, direct bilirubin, and hematocrit-and explained 41.4% variance in the tacrolimus concentration/dose ratio. It achieved an area under the receiver operating characteristic curve of 0.804 (95% confidence interval, 0.746-0.861). The Hosmer-Lemeshow test yielded a nonsignificant P value of .790, suggesting good fit of the model. The predicted dose exhibited good correlation with the observed dose in the early postoperative period (r = 0.748, P less than .001). Our study provided a genotype-guided prediction model for tacrolimus initial dose, which may help to guide individualized dosing of tacrolimus in the lung transplant population in clinical practice.

A Physiologically Based Pharmacokinetic Approach to Recommend an Individual Dose of Tacrolimus in Adult Heart Transplant Recipients

Tacrolimus is the principal immunosuppressive drug which is administered after heart transplantation. Managing tacrolimus therapy is challenging due to a narrow therapeutic index and wide pharmacokinetic (PK) variability. We aimed to establish a physiologically based pharmacokinetic (PBPK) model of tacrolimus in adult heart transplant recipients to optimize dose regimens in clinical practice. A 15-compartment full-PBPK model (Simbiology® Simulator, version 5.8.2) was developed using clinical observations from 115 heart transplant recipients. This study detected 20 genotypes associated with tacrolimus metabolism. CYP3A5*3 (rs776746), CYP3A4*18B (rs2242480), and IL-10 G-1082A (rs1800896) were identified as significant genetic covariates in tacrolimus pharmacokinetics. The PBPK model was evaluated using goodness-of-fit (GOF) and external evaluation. The predicted peak blood concentration (Cmax) and area under the drug concentration-time curve (AUC) were all within a two-fold value of the observations (fold error of 0.68-1.22 for Cmax and 0.72-1.16 for AUC). The patients with the CYP3A5*3/*3 genotype had a 1.60-fold increase in predicted AUC compared to the patients with the CYP3A5*1 allele, and the ratio of the AUC with voriconazole to alone was 5.80 when using the PBPK model. Based on the simulation results, the tacrolimus dosing regimen after heart transplantation was optimized. This is the first PBPK model used to predict the PK of tacrolimus in adult heart transplant recipients, and it can serve as a starting point for research on immunosuppressive drug therapy in heart transplant patients.

Influence of CYP3A5, IL-10 polymorphisms and metabolism rate on tacrolimus exposure in renal post-transplant recipients

Aim: To investigate the influence of CYP3A5 and IL-10 polymorphisms on tarcolimus metabolism and renal function for renal transplantation recipients at a stable period. Methods: CYP3A5 and IL-10 polymorphisms, together with other clinical factors, were collected for 149 renal transplantation patients at postoperative stable period. Statistics analysis was performed to explore key factors affecting tarcolimus metabolism. Results: CYP3A5 6986A >G and IL-10 -819C >T significantly impacted tacrolimus metabolism (p < 0.001). CYP3A5 6986A >G G allele and IL-10 -819C >T T allele were associated with poorer tacrolimus metabolic capability. Patients with various tacrolimus metabolism rates presented little difference in renal functions at stable period. Conclusion: Genotyping of CYP3A5 and IL-10 might benefit the precision dosage of tacrolimus for renal transplantation recipients.

UHPLC-MS/MS method for the determination of azithromycin in human plasma of pediatric patients

The determination of azithromycin in human plasma of pediatric patients was performed with a ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) assay. A simple sample preparation of protein precipitation was used and the separation was achieved on a C18 column by the gradient mixture of mobile phase A ( 0.1% acetic acid and 3 mM ammonium acetate in water) and the mobile phase B (0.1% acetic acid and 3 mM ammonium acetate in the solution of acetonitrile, methanol and water, 47.5/47.5/5, V/V/V). The multiple reaction monitoring (MRM) mode was adopted to monitor the precursor-to-product ion transitions of m/z 749.6→m/z 591.5 for azithromycin and m/z 753.6→m/z 595.5 for azithromycin-¹³ C-d3 (IS) at positive ionization mode. The calibration curve ranged between 0.5 ng·mL^-1 and 500.0 ng·mL^-1 and the correlation coefficient was greater than 0.99. The intra- and inter-batch precision was less than 13.7%. Accuracy determined at four concentrations ranged from 99.5% to 110.8%. The extraction recoveries were more than 95% and the matrix effects were 98% - 100%. The stability under various conditions were acceptable with the accuracy deviation within 9.2%. In conclusion, our method was simple, sensitive and reliable for quantification of azithromycin in plasma among pediatric patients.

Impact of Genetic Polymorphisms at the Promoter area of IL-10 Gene on Tacrolimus Level in Jordanian Renal Transplantation Recipients

Background Tacrolimus is a widely used immunosuppressant that prevents the solid organ transplant rejection. The pharmacokinetics of Tacrolimus show considerable variability. interleukin-10 (IL-10), in the host’s immune response after transplantation contributes to the variable CYP3A-dependent drug disposition of Tacrolimus. In current study, our aim is to evaluate the impact of single nucleotide polymorphisms (SNP) in the promoter region of of IL-10 on Tacrolimus dose requirements and the Dose Adjusted Concentration (DAC) of Tacrolimus among kidney transplantation recipients.  Methods Blood levels of Tacrolimus were measured using Micorparticle Enzyme Immunoassay (MEIA) for six months post-transplantation. Genotyping analysis was utilized using specific Polymerase Chain Reaction (PCR) followed by sequencing methods for 98 Jordanian kidney transplant recipients. Results Genotyping frequencies of IL-10 (-592) were (CC/CA/AA: 38, 46.7, 15.2%); IL-10 (-819) were (CC/CT/TT: 40.4, 44.1, 15.1%); and IL-10 (-1082) were (AA/AG/GG: 42.6, 44.7, 12.8%). The impact of IL-10 (-1082) on Tacrolimus DAC was gender dependent. Men carrying at least one A allele had significantly lower DAC than men carrying GG genotyping only in the first month post-transplantation [88.2±32.1 vs. 117.5±22.5 ng/ml per mg/kg/day, p=0.04].. Conclusion Our current study showed that the interaction between gender and IL-10 -1082 affects Tacrolimus DAC in Jordanian kidney transplantation recipients during the first month post-transplantation.

The impact of cytochrome P450 3A5 genotype on early tacrolimus metabolism and clinical outcomes in lung transplant recipients

Background Tacrolimus (Tac) is the cornerstone of immunosuppressant therapy after lung transplantation (LTx). It shows great inter-individual variability in pharmacokinetics, which could partly be explained by pharmacogenetic factors. Aim We aim to investigate the influence of cytochrome P450 3A5 (CYP3A5) genotypes on early post-LTx Tac metabolism and whether it is affected by concomitant use of azole antifungals. Also, we explored the association between CYP3A5 genotype and clinical outcomes. Method 90 recipients who underwent LTx from 2017 to 2019 were enrolled in the study. The effect of CYP3A5 genotype on Tac metabolism and interaction with azole antifungals were assessed during week 1-4 after transplantation. Associations between CYP3A5 genotype and the incidence of acute kidney injury (AKI), length of hospital stay and mortality were analyzed. ResultsCYP3A5*1 carriers had lower dose adjusted concentration (C/D) than CYP3A5*3/*3 group at all time points (p < 0.05). The dose ratio of CYP3A5*1 carriers to CYP3A5*3/*3 was between 1.3 and 2.4 when comparable concentrations were reached. Use of azole antifungals did not blunt the effect of CYP3A5 genotypes on Tac metabolism. Logistic regression showed Tac concentration ≥ 7.5 ng/mL at week 1 was associated with higher incidence of AKI. No statistically significant difference was found between CYP3A5 genotypes and the length of hospital stay. Kaplan-Meier analysis showed no statistically significant difference between 30-day or 1-year mortality and CYP3A5 genotype. Conclusion CYP3A5 genotype could affect Tac metabolism early after LTx. However, it had no influence on the incidence of AKI, length of hospital stay and mortality.

Distinct Effects of Inflammation on Cytochrome P450 Regulation and Drug Metabolism: Lessons from Experimental Models and a Potential Role for Pharmacogenetics

Personalized medicine strives to optimize drug treatment for the individual patient by taking into account both genetic and non-genetic factors for drug response. Inflammation is one of the non-genetic factors that has been shown to greatly affect the metabolism of drugs—primarily through inhibition of cytochrome P450 (CYP450) drug-metabolizing enzymes—and hence contribute to the mismatch between the genotype predicted drug response and the actual phenotype, a phenomenon called phenoconversion. This review focuses on inflammation-induced drug metabolism alterations. In particular, we discuss the evidence assembled through human in-vitro models on the effect of inflammatory mediators on clinically relevant CYP450 isoform levels and their metabolizing capacity. We also present an overview of the current understanding of the mechanistic pathways via which inflammation in hepatocytes may modulate hepatic functions that are critical for drug metabolism. Furthermore, since large inter-individual variability in response to inflammation is observed in human in-vitro models and clinical studies, we evaluate the potential role of pharmacogenetic variability in the inflammatory signaling cascade and how this can modulate the outcome of inflammation on drug metabolism and response.

Tacrolimus and Sirolimus Once Daily Monotherapy Regimen as a Safe and Effective Long-Term Maintenance Immunosuppressive Therapy in Pediatric Liver Transplantation

BACKGROUND

Long-term efficiency of attenuated immunosuppressive therapies is not well characterized in pediatric liver transplantation (LT).

OBJECTIVE

To assess the efficiency of tacrolimus once daily (TAC-OD) and sirolimus once daily (SLR-OD) immunosuppression in pediatric LT.

METHODS

We retrospectively evaluated 59 children who underwent LT in our center during 2002 to 2016. Those including children who underwent planned decrease in immunosuppressant dose (stable clinical conditions after 2 years of LT), and those who underwent unplanned decrease in immunosuppressant dose (because of complications such as post-transplant lymphoproliferative disorder [PTLD] and renal failure).

RESULTS

25 of 59 children underwent planned decrease in immunosuppressant dosage (mean±SD duration of 4.5±1.8, range: 3-11 years); 34 had unplanned decrease (mean±SD of 1.3±0.6, range: 0.5-2.6 years). 19 of 25 children with planned conversion received TAC-OD; 6 received SLR-OD (22 with 1 mg/day dose, and 3 with 1 mg every two days). Of 34 children with unplanned conversion, 27 received TAC-OD, 7 SLR-OD (25 children with 1 mg/day, 7 with 1 mg every two days, 1 with 0.5 mg/day TAC, and 1 with 0.5 mg TAC every two days). We found no adverse events including acute or chronic graft rejection, renal insufficiency, infections, PTLDs, or cardiovascular thrombotic events after initiation of the modified immunosuppression in none of the groups.

CONCLUSION

TAC-OD or SLR-OD monotherapies are safe and effective for long-term management of LT children with either stable clinical conditions or those with LT complications.