Effect of bifendate on the pharmacokinetics of cyclosporine in relation to the CYP3A4*18B genotype in healthy subjects

Antioxidant activity and hepatoprotective effect of 10 medicinal herbs on CCl4-induced liver injury in mice

BACKGROUND

Many natural products confer health benefits against diverse diseases through their antioxidant activities. Carbon tetrachloride (CCl₄) is often used in animal experiments to study the effects of substances on liver injury and the related mechanisms of action, among which oxidative stress is a major pathogenic factor.

AIM

To compare antioxidant and hepatoprotective activities of ten herbs and identify and quantify phytochemicals for the one with strongest hepatoprotection.

METHODS

The antioxidant activity of ten medicinal herbs was determined by both ferric-reducing antioxidant power and Trolox equivalent antioxidant capacity assays. The total phenolic and flavonoid contents were determined by Folin–Ciocalteu method and aluminum chloride colorimetry, respectively. Their effects on CCl₄-induced oxidative liver injury were evaluated and compared in a mouse model by administrating each water extract (0.15 g/mL, 10 mL/kg) once per day for seven consecutive days and a dose of CCl₄ solution in olive oil (8%, v/v, 10 mL/kg). The herb with the strongest hepatoprotective performance was analyzed for the detailed bioactive components by using high-performance liquid chromatography-electrospray ionization source-ion trap tandem mass spectrometry.

RESULTS

The results revealed that all tested herbs attenuated CCl₄-induced oxidative liver injury; each resulted in significant decreases in levels of serum alanine transaminase, aspartate transaminase, alkaline phosphatase, and triacylglycerols. In addition, most herbs restored hepatic superoxide dismutase and catalase activities, glutathione levels, and reduced malondialdehyde levels. Sanguisorba officinalis (S. officinalis) L., Coptis chinensis Franch., and Pueraria lobata (Willd.) Ohwi root were the three most effective herbs, and S. officinalis L. exhibited the strongest hepatoprotective effect. Nine active components were identified in S. officinalis L. Gallic acid and (+)-catechin were quantified (7.86 ± 0.45 mg/g and 8.19 ± 0.57 mg/g dried weight, respectively). Furthermore, the tested herbs displayed a range of in vitro antioxidant activities proportional to their phenolic content; the strongest activities were also found for S. officinalis L.

CONCLUSION

This study is of value to assist the selection of more effective natural products for direct consumption and the development of nutraceuticals or therapeutics to manage oxidative stress-related diseases.

Association Between CYP3A4 and CYP3A5 Genotypes and Cyclosporine's Blood Levels and Doses among Jordanian Kidney Transplanted Patients

BACKGROUND

Cyclosporine is used as an immunosuppressive agent in kidney transplantation. It has a narrow therapeutic window. Cyclosporine is predominantly metabolized by CYP3A4 and CYP3A5. The most common Single Nucleotide Polymorphisms (SNPs) affecting cyclosporine metabolism (CYP3A4*1B, CYP3A4*1G, CYP3A4*22 and CYP3A5*3) were investigated among Jordanian kidney transplanted patients to find out the genotypes and allele frequencies of these SNPs. Additionally, this study investigated whether genotypes of CYP3A4 and CYP3A5 affect C2 blood levels, dosing of cyclosporine and the prevalence of acute rejection.

METHODS

Blood samples of 109 adult patients taking cyclosporine as their primary immunosuppressant for kidney transplantation were collected from the Prince Hamzah Hospital, Amman, Jordan. Patients' first C2 blood levels and their first two given doses were collected. Patients were genotyped for the four SNPs using Polymerase Chain Reaction- restriction Fragment Length Polymorphism (PCR-RFLP) assay method.

RESULTS

Allele frequencies among Jordanian patients for CYP3A4*1B, CYP3A4*1G, CYP3A4*22 and CYP3A5*3 were 0.037, 0.399, 0.037 and 0.271, respectively. There was a significant association between CYP3A4*22 and mean difference in the second and first given doses (P=0.034). There was a big difference between CYP3A4*22 and the mean of the first C2 blood levels (P=0.063).

CONCLUSION

There was a strong association between CYP3A4*22 and the mean difference between the second and first given doses. There was a trend of significant difference between the mean of the first C2 blood levels among heterozygous CYP3A4*22 patients. Pharmacogenomics may hold promise in assisting the prediction of the best cyclosporine dose and C2 blood level among Jordanian kidney transplant patients.

Pharmacokinetic and Pharmacogenetic Factors Contributing to Platelet Function Recovery After Single Dose of Ticagrelor in Healthy Subjects

Objectives: This study aimed to elucidate the contribution of candidate single nucleotide polymorphisms (SNPs) related to pharmacokinetics on the recovery of platelet function after single dose of ticagrelor was orally administered to healthy Chinese subjects.

Methods: The pharmacokinetic profiles of ticagrelor and its metabolite AR-C124910XX (M8), and the platelet aggregation (PA), were assessed after 180 mg of single-dose ticagrelor was orally administered to 51 healthy Chinese subjects. Effects of CYP2C19^*2, CYP2C19^*3, CYP3A5^*3, UGT1A1^*6, UGT1A1^*28, UGT2B7^*2, UGT2B7^*3, SLCO1B1 388A>G, and SLCO1B1 521T>C, on the pharmacokinetics of ticagrelor and M8, and platelet function recovery were investigated.

Results: The time to recover 50% of the maximum drug effect (RT₅₀) ranging from 36 to 126 h with 46.9% CV had a remarkable individual difference and was positively associated with the half-life (t_1/2) of M8 (r = 0.3901, P = 0.0067). The time of peak concentration (T_max) of ticagrelor for CYP2C19^*3 GG homozygotes was significantly higher than that of GA heterozygotes (P = 0.0027, FDR = 0.0243). Decreased peak concentration (C_max) of M8 was significantly associated with SLCO1B1 388A>G A allele (P = 0.0152, FDR = 0.1368). CYP2C19^*2 A was significantly related to decreased C_max of M8 (P = 0.0455, FDR = 0.2048). While, the influence of these nine SNPs on the recovery of platelet function was not significant.

Conclusion: Our study suggests that the elimination of M8 is an important factor in determining the recovery of platelet function. Although CYP2C19 and SLCO1B1 genetic variants were related to the pharmacokinetics of ticagrelor or M8, they did not show a significant effect on the platelet function recovery in this study.

Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT03092076, identifier: NCT03092076

Effects of CYP3A4*1G and CYP3A5*3 polymorphisms on pharmacokinetics of tylerdipine hydrochloride in healthy Chinese subjects

The aim of this analysis was to explore the influence of CYP3A4*1G and CYP3A5*3 polymorphisms on the pharmacokinetics of tylerdipine in healthy Chinese subjects. A total of 64 and 63 healthy Chinese subjects were included and identified as the genotypes of CYP3A4*1G and CYP3A5*3, respectively. Plasma samples were collected for up to 120 h post-dose to characterize the pharmacokinetic profile following single oral dose of the drug (5, 15, 20, 25 and 30 mg). Plasma levels were measured by a high-performance liquid chromatography-mass spectrometry (LC-MS/MS). The pharmacokinetic parameters were calculated using non-compartmental method. The maximum concentration (C_max) and the area under the curve (AUC_0-24 h) were all corrected by the dose given. In the wild-type group, the mean dose-corrected AUC_0-24 h was 1.35-fold larger than in CYP3A4*1G carriers (p = .018). Among the three CYP3A5 genotypes, there showed significantly difference (p = .008) in the t_1/2, but no significant difference was observed for the AUC_0-24 h and C_max. In subjects with the CYP3A5*3/*3 genotype, the mean t_1/2 was 1.35-fold higher than in CYP3A5*1/*1 group (p = .007). And the t_1/2 in CYP3A5*3 carriers also was 1.32-fold higher than in the wild-type group (p = .004). CYP3A4*1G and CYP3A5*3 polymorphisms may influence tylerdipine pharmacokinetic in healthy Chinese subjects.

Effect of CYP3A4∗1G and CYP3A5∗3 Polymorphisms on Pharmacokinetics and Pharmacodynamics of Ticagrelor in Healthy Chinese Subjects

Ticagrelor is the first reversible, direct-acting, potent P2Y₁₂ receptor antagonist in management of acute coronary syndromes. It is rapidly absorbed and extensively metabolized. AR-C124910XX, the major active metabolite, antagonizes the P2Y₁₂ receptor at approximately equal potency. The metabolism of ticagrelor to AR-C124910XX involves CYP3A4 and CYP3A5. CYP3A polymorphisms have been well documented, and CYP3A4^∗1G (g.20230G>A, rs2242480) and CYP3A5^∗3 (g.6986A>G, rs776746) are the most important single nucleotide polymorphisms in Chinese. Genetic differences in CYP3A4 and CYP3A5 expression in human volunteers and patients might affect the clearance of ticagrelor or AR-C124910XX in vivo resulting in subsequent variable patient response. Thus, this study is designed to explore the effects of CYP3A4^∗1G and CYP3A5^∗3 polymorphisms on the pharmacokinetics and pharmcodynamics of ticagrelor in healthy Chinese subjects. The results indicated that the CYP3A4^∗1G polymorphism significantly influenced the pharmacokinetics of AR-C124910XX, and it may be more important than CYP3A5^∗3 with respect to influencing ticagrelor pharmacokinetics by increasing CYP3A4 activity. However, the significant effect of CYP3A4^∗1G polymorphism on AR-C124910XX plasma levels did not translate into detectable effect on inhibition of platelet aggregation. Therefore, it seems not necessary to adjust the dosage of ticagrelor according to the CYP3A4 or 3A5 genotype.

Clinical implementation of pharmacogenetics in kidney transplantation: calcineurin inhibitors in the starting blocks

Pharmacogenetics has generated many expectations for its potential to individualize therapy proactively and improve medical care. However, despite the huge amount of reported genetic associations with either pharmacokinetics or pharmacodynamics of drugs, the translation into patient care is still slow. In fact, strong evidence for a substantial clinical benefit of pharmacogenetic testing is still limited, with a few exceptions. In kidney transplantation, established pharmacogenetic discoveries are being investigated for application in the clinic to improve efficacy and to limit toxicity associated with the use of immunosuppressive drugs, especially the frequently used calcineurin inhibitors (CNIs) tacrolimus and ciclosporin. The purpose of the present review is to picture the current status of CNI pharmacogenetics and to discuss the most promising leads that have been followed so far.

CYP3A4*22: promising newly identified CYP3A4 variant allele for personalizing pharmacotherapy

Many studies have attempted to explain the interindividual variability observed in drug metabolism by assessing the impact of SNPs in genes implicated in drug absorption, distribution, metabolism and excretion pathways. Particular attention has been paid to the CYP450s. CYP3A4 is the main CYP isoform in human liver and intestine and is involved in the metabolism of many drugs. Its activity, however, is characterized by widespread variation in the general population, which is thought to have a genetic basis. A new CYP3A4 allele (CYP3A4*22; rs35599367 C>T in intron 6) with a frequency of 5-7% in the Caucasian population was recently discovered through its association with low hepatic CYP3A4 expression and CYP3A4 activity, and showing effects on statin, tacrolimus and cyclosporine metabolism. This review will summarize the current literature on phenotypes linked to this new promising CYP3A4 genetic marker SNP and discusses the potential clinical relevance.

Association of CYP3A polymorphisms with the pharmacokinetics of cyclosporine A in early post-renal transplant recipients in China

AIM

To evaluate retrospectively the association of cytochrome P450 3A (CYP3A) and ATP-binding cassette sub-family B member 1 (ABCB1) gene polymorphisms with the pharmacokinetics of cyclosporine A (CsA) in Chinese renal transplant patients.

METHODS

One hundred and twenty-six renal transplant patients were recruited. Blood samples were collected, and corresponding clinical indices were recorded on the seventh day after the procedure. The patients were genotyped for CYP3A4*1G, CYP3A5*3C, ABCB1 1236 C>T, ABCB1 2677 G>T/A, and ABCB1 3435 C>T polymorphisms. Whole blood trough concentrations of CsA at time zero (C(0)) were measured before the drug administration. A multiple regression model was developed to analyze the effects of genetic factors on the CsA dose-adjusted C(0) (C(0)/dose) based on several clinical indices.

RESULTS

The CYP3A5*3C polymorphism influenced the C(0) and C(0)/dose of CsA, which were significantly higher in patients with the GG genotype than in patients with the AA or GA genotypes. No significant differences were detected for other SNPs (CYP3A4*1G, ABCB1 1236 C>T, ABCB1 2677 G>T/A, and ABCB1 3435 C>T). In a univariate analysis using Pearson's correlation test, age, hemoglobin, blood urea nitrogen and blood creatinine levels were significantly correlated with the log-transformed CsA C(0)/dose. In the multiple regression model, CYP3A5*3C, age, hemoglobin and blood creatinine level were associated with the log-transformed CsA C(0)/dose.

CONCLUSION

CYP3A5*3C correlates with the C(0)/dose of CsA on the seventh day after renal transplantation. The allele is a putative indicator for the optimal CsA dosage in the early phase of renal transplantation in the Chinese population.

Effect of CYP3A and ABCB1 single nucleotide polymorphisms on the pharmacokinetics and pharmacodynamics of calcineurin inhibitors: Part I

The calcineurin inhibitors ciclosporin (cyclosporine) and tacrolimus are immunosuppressant drugs used for the prevention of organ rejection following transplantation. Both agents are metabolic substrates for cytochrome P450 (CYP) 3A enzymes--in particular, CYP3A4 and CYP3A5--and are transported out of cells via P-glycoprotein (ABCB1). Several single nucleotide polymorphisms (SNPs) have been identified in the genes encoding for CYP3A4, CYP3A5 and P-glycoprotein, including CYP3A4 -392A>G (rs2740574), CYP3A5 6986A>G (rs776746), ABCB1 3435C>T (rs1045642), ABCB1 1236C>T (rs1128503) and ABCB1 2677G>T/A (rs2032582). The aim of this review is to provide the clinician with an extensive overview of the recent literature on the known effects of these SNPs on the pharmacokinetics of ciclosporin and tacrolimus in solid-organ transplant recipients. Literature searches were performed, and all relevant primary research articles were critiqued and summarized. Influence of the CYP3A4 -392A>G SNP on the pharmacokinetics of either ciclosporin or tacrolimus appears limited. Variability in CYP3A4 expression due to environmental factors is likely to be more important than patient genotype. Influence of the CYP3A5 6986A>G SNP on the pharmacokinetics of ciclosporin is also uncertain and likely to be small. CYP3A4 may play a more dominant role than CYP3A5 in the metabolism of ciclosporin. The CYP3A5 6986A>G SNP has a well established influence on the pharmacokinetics of tacrolimus. Several studies in kidney, heart and liver transplant recipients have reported an approximate halving of tacrolimus dose-adjusted trough concentrations and doubling of tacrolimus dose requirements in heterozygous or homozygous carriers of a CYP3A5*1 wild-type allele compared with homozygous carriers of a CYP3A5*3 variant allele. Carriers of a CYP3A5*1 allele take a longer time to reach target blood tacrolimus concentrations. Influence of ABCB1 3435C>T, 1236C>T and 2677G>T/A SNPs on the pharmacokinetics of ciclosporin and tacrolimus remains uncertain, with inconsistent results. Genetic linkage between the three variant genotypes suggests that the pharmacokinetic effects are complex and not related to any one ABCB1 SNP. It is likely that these polymorphisms exert a small but combined effect, which is additive to the effects of the CYP3A5 6986A>G SNP. In liver transplant patients, recipient and donor liver genotypes may act together in determining overall drug disposition, hence the importance of assessing both. Studies with low patient numbers may account for many inconsistent results to date. Meta-analyses of the current data should help resolve some discrepancies. The majority of studies have only evaluated the effects of individual SNPs; however, multiple polymorphisms may interact to produce a combined effect. Further haplotype analyses are likely to be useful. It is not yet clear whether pharmacogenetic profiling of calcineurin inhibitors will be a useful clinical tool for personalizing immunosuppressant therapy.