Effects of genetic polymorphisms of CYP3A4, CYP3A5 and MDR1 on cyclosporine pharmacokinetics after renal transplantation

1. The calcineurin inhibitor cyclosporine is widely used to prevent allograft rejection after solid organ transplantation. It has a narrow therapeutic index and shows considerable interindividual differences in its pharmacokinetics. Interindividual differences in the activity and expression of the metabolising enzymes cytochrome P450 (CYP) 3A4 and 3A5 and the multidrug efflux pump P-glycoprotein (P-gp) contribute considerably to cyclosporine pharmacokinetics. Variability in the activity of CYP3A4, CYP3A5 and P-gp could be considered to result from genetic polymorphisms encoding their genes. 2. The aim of the present study was to evaluate retrospectively the effects of genetic polymorphisms of CYP3A4, CYP3A5 and MDR1 on cyclosporine dose adjusted trough blood concentration during the early period after renal transplantation in Chinese patients. 3. One hundred and six renal transplant recipients in China were genotyped by polymerase chain reaction-restriction fragment length polymorphism for CYP3A4*18A, CYP3A5*3 and MDR1 C3435T. Cyclosporine whole blood levels were measured by fluorescence polarization immunoassay. Dose-adjusted trough blood concentrations (C(0)) were determined and compared among the different genotype groups. 4. The frequency of the CYP3A4*18A, CYP3A5*3 and MDR1 C3435T variant alleles were 0.005 (95% confidence interval (CI) 0.048, 0.0049), 0.783 (95% CI 0.781, 0.785) and 0.528 (95% CI 0.526, 0.531), respectively, and these alleles exhibited incomplete linkage disequilibrium. The median cyclosporine dose-adjusted C(0) in CYP3A5*1/*1 genotype subjects (n = 6) was 14.8 ng/mL per mg per kg (range 11.1-26.8 ng/mL per mg per kg), in CYP3A5*1/*3 patients (n = 34) it was 23.7 ng/mL per mg per kg (range 9.0-61.0 ng/mL per mg per kg) and for CYP3A5*3/*3 patients (n = 66) it was 26.4 ng/mL per mg per kg (range 9.8-85.8 ng/mL per mg per kg; P = 0.012, Kruskal-Wallis test). Accordingly, cyclosporine dose-adjusted C0 was larger in CYP3A5 non-expressors than expressors in the first week after renal transplantation. In addition, wild-type homozygotes (n = 21) for MDR1 C3435T had a slight but significantly lower dose-adjusted C0 compared with heterozygotes (n = 58): 17.7 (10.3-60.8) versus 26.4 (9.0-67.3) ng/mL per mg per kg, respectively (P = 0.014, Mann-Whitney U-test). 5. In conclusion, the present study shows that genetic polymorphisms in CYP3A5 may be responsible, in part, for the large interindividual variability of cyclosporine pharmacokinetics during the early phase after renal transplantation in Chinese patients. Patients with the CYP3A5*3 variant genotype require a low dose of cyclosporine to reach target levels compared with those with the CYP3A5*1 allele.     

Association of MDR1, CYP3A4*18B, and CYP3A5*3 polymorphisms with cyclosporine pharmacokinetics in Chinese renal transplant recipients

Objective  The objective of this study was to retrospectively evaluate the effects of MDR1, CYP3A4*18B, and CYP3A5*3 genetic polymorphisms on cyclosporine A (CsA) pharmacokinetics in Chinese renal transplant patients during the first month after transplantation. Methods  A total of 103 renal transplant recipients receiving CsA were genotyped for MDR1 (C1236T, G2677T/A, and C3435T), CYP3A4*18B, and CYP3A5*3. The predose and 2-h postdose concentrations of CsA (C₀ and C₂, respectively) were determined by fluorescence polarization immunoassay, and their relationships with corresponding genotypes and haplotypes were investigated. Results  Patients with a CYP3A4*1/*1 genotype were found to have a higher dose-adjusted concentration compared with those with CYP3A4*18B/*18B, as follows: for C₂, 19.3% (P = 0.008) during days 8-15, 35.2% (P = 0.008) during days 16–30, and for C₀, 39.7% (P = 0.012) during days 16–30. The dose-adjusted C₀ was higher in patients with MDR1 1236CC compared with those with 1236TT in the first month postoperation. The dose-adjusted C₀ in patients with the CYP3A5*3/*3 genotype was 25.5% and 30.7% higher than those with the wild-type genotype during days 8–15 (P = 0.011) and days 16–30 (P = 0.015), respectively. Haplotype analysis revealed that the dose-adjusted C₀ was higher in the first month following surgery in carriers of haplotype MDR1 CAC than in noncarriers. Polymorphisms of MDR1 and CYP3A5*3 did not affect dose-adjusted C_2. Conclusion  The data suggests that the CYP3A4*18B genotype affects CsA pharmacokinetics during the first month following surgery in Chinese renal transplant recipients. Patients with CYP3A4*18B alleles may require higher doses of CsA to reach the target levels. Large prospective studies may be needed to further explore the impact of MDR1 and CYP3A5*3 polymorphisms on CsA pharmacokinetics in renal transplant recipients.     

CYP3A4/5、ABCB1基因单倍型与中国肾移植患者他克莫司血药谷浓度相关性的研究

目的:探讨CYP3A4*18B、CYP3A5*3、ABCB1基因单倍型对中国肾移植患者术后一月内他克莫司谷浓度(C0/D)的影响。方法:采用限制性片段长度多态性技术分析46名肾移植患者CYP3A4*18B、CYP3A5*3、ABCB1(外显子C1236T、G2677A/T、C3435T)基因型,采用酶增强免疫测定技术测定患者C0值。结果:经分析患者CYP3A4*18B、CYP3A5*3、ABCB1(C1236T,G2677A/T,C3435T)等位基因频率分别为0.304、0.707、0.554、0.478和0.304,均符合HardyWeinberg平衡。CYP3A4-3A5、G2677A/T-C3435T及C1236T-C3435T间均表现为连锁不平衡。术后8~15、16~30天内CYP3A4*18B与患者FK506 C0/D值显著相关,野生型患者C0/D值分别为杂合及突变型患者的1.34和1.67倍。CYP3A5*3基因也与患者FK506 C0/D值显著相关。突变型患者C0/D值在术后1~7、8~15及16~30天时分别为野生及杂合型患者的1.56、1.98及1.99倍。单倍型分析发现CYP3A4/5单倍型GG型携带者C0/D值较非携带者在移植术后8~15、16~30天显著性增加1.43、1.77倍。未观察到ABCB1基因多态性及单倍型对FK506血药浓度的影响。结论:仅CYP3A4/5单倍型与他克莫司C0/D值显著相关,移植前对CYP3A4/5单倍型进行检测将有利于他克莫司给药剂量的调整。     

Progressive decline in tacrolimus clearance after renal transplantation is partially explained by decreasing CYP3A4 activity and increasing haematocrit

Aims

The long-term disposition of tacrolimus following kidney transplantation is characterized by a gradual decrease in dose requirements and increase in dose-corrected exposure. This phenomenon has been attributed to a progressive decline in cytochrome P450 3A4 (CYP3A4) activity, although this has never been demonstrated in vivo.

Methods

Sixty-five tacrolimus- and 10 cyclosporine-treated renal transplant recipients underwent pharmacokinetic testing at day 7 and months 1, 3, 6 and 12 after transplantation, including 8-h area under the concentration-time curve (AUC) for tacrolimus or cyclosporine and assessment of CYP3A4 activity using oral and intravenous midazolam (MDZ) drug probes.

Results

Tacrolimus clearance decreased gradually throughout the entire first year but only in CYP3A5*3/*3 homozygous recipients (25.6 ± 11.1 l h^–1 at day 7; 17 ± 9.1 l h^–1 at month 12; P < 0.001). In mixed model analysis, decreasing CYP3A4 activity, measured by apparent oral MDZ clearance (924 ± 443 ml min^–1 at day 7 vs. 730 ± 344 ml min^–1 at month 1; P < 0.001), explained 55.4% of the decline in tacrolimus clearance in the first month. CYP3A4 activity decreased by 18.9 ml min^–1 for every milligram of methylprednisolone dose tapering within the first month; beyond this point it remained stable. A gradual rise in haematocrit throughout the entire first year explained 31.7% of the decrease in tacrolimus clearance in the first month and 23.6% of the decrease between months 1 and 12. Cyclosporine clearance did not change over time.

Conclusions

The maturation of tacrolimus disposition in the first year after renal transplantation observed in CYP3A5*3/*3 homozygous patients can partly be explained by a (steroid tapering-related) decline in CYP3A4 activity and a progressive increase in haematocrit.     

CYP3A4,CYP3A5和MDR1基因多态性对环孢素处置的影响

环孢素是一个广泛用于器官移植患者的免疫抑制剂,具有治疗指数窄,不同个体间药代动力学差异较大的特点。它主要通过肝脏和小肠的CYP3A4和CYP3A5代谢;同时它又是药物转运体的底物。不同个体间药物代谢酶和转运体活性的差异可能是造成不同器官移植患者环孢素药代动力学差异的主要原因。而遗传因素即编码药物代谢酶和转运体基因序列的差异可能是其产生活性差异的分子机制。因此,从编码药物代谢酶和转运体的基因入手,可能会为器官移植患者提供最优的治疗方案。     

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

1. 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.

2. 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.

3. 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).

4. CYP3A4*1G and CYP3A5*3 polymorphisms may influence tylerdipine pharmacokinetic in healthy Chinese subjects.

     

Recipient ABCB1, donor and recipient CYP3A5 genotypes influence tacrolimus pharmacokinetics in liver transplant cases

BackgroundEffective immunosuppression through optimization of trough levels tacrolimus reduces post-transplant mortality rate in liver transplant cases.MethodsMeta-analysis was carried out to evaluate how donor/recipient CYP3A5 (n = 678) and recipient ABCB1 (n = 318) genotypes influence tacrolimus pharmacokinetics till one-month of transplantation.ResultsThe donor CYP3A5*3/*3 genotype exhibited higher concentration/dose (C/D) ratio of tacrolimus in week 1 (mean difference: 65.04, 95% CI: 15.30–114.79 ng/ml/mg/kg), week 2 (mean difference: 21.7, 95% CI: 12.6–30.9 ng/ml/mg/kg) and week 4 (mean difference: 43.28, 95% CI: 17.09 – 69.49 ng/ml/mg/kg) compared to *1/*1 and *1/*3 genotypes. The recipient CYP3A5 *3/*3 genotype did not showed significant difference in tacrolimus C/D ratio in week 1 compared to other two genotypes. However, week 2 (mean difference: 44.16, 95% CI: 3.68–84.65 ng/ml/mg/kg) and week 4 (mean difference: 43.74, 95% CI: 12.50–75.00 ng/ml/mg/kg) availability was higher in *3/*3 mutant recipients. However, the recipient ABCB1 3435 C > T polymorphism has no significant influence on tacrolimus pharmacokinetics till one month of transplant.ConclusionsThe donor and recipient CYP3A5*3 polymorphism influences tacrolimus pharmacokinetics in the first month post-transplantation, whereas the association with recipient ABCB1 3435 C > T is inconclusive.     

Ethnic differences in the distribution of CYP3A5 gene polymorphisms

The genetic polymorphism affecting the CYP3A5 enzyme is responsible for interindividual and interethnic variability in the metabolism of CYP3A5 substrates. The full extent of the CYP3A5 genetic polymorphism was analysed in French Caucasian, Gabonese and Tunisian populations using a polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) strategy. In the three populations, eight, 17 and ten single nucleotide polymorphisms (SNPs), respectively, were identified, among which nine correspond to rare new mutations. Also identified were 16 alleles including eight new allelic variants. Significant differences were observed in the distribution of these alleles. Particularly, the frequency of the CYP3A5*3C null allele in French Caucasians (81.3%) and in Tunisians (80.0%) is higher than in the Gabonese population (12.5%) (p?相似文献   

肺移植患者术后使用他克莫司1年CYP3A5、CYP3A4、ABCB1、POR~*28基因多态性与他克莫司个体化用药的关系研究

目的:研究肺移植患者术后使用他克莫司1年CYP3A5、CYP3A4、ABCB1、POR*28基因多态性与他克莫司给药剂量(D)和稳态血药浓度/给药剂量比值(c0/D)的关系。方法:采用回顾性分析方法,选取2017年5月-2018年5月期间在中日友好医院接受肺移植术的46例受试者为研究对象,统计受试者术后使用他克莫司1年后他克莫司的c0和D,并计算c0/D。收集受试者CYP3A5(rs776746)、CYP3A4(rs2242480、rs28371759)、ABCB1(rs1045642、rs2032582、rs1128503)和POR*28(rs1057868)位点的基因型,对基因多态性与D、c0/D的关系进行统计学分析。结果:本研究中涉及位点的基因型频率均符合Hardy-Weinberg平衡(P>0.05)。维持他克莫司c0在治疗窗范围内的条件下,受试者的CYP3A5(rs776746)和CYP3A4(rs2242480)基因型多态性对他克莫司的D、c0/D有显著影响(P<0.05);其他位点各基因型之间的D、c0/D差异均无统计学意义(P>0.05)。联合CYP3A5(rs776746)和CYP3A4(rs2242480)两个位点分析受试者CYP3A代谢型发现,同时携带CYP3A5(rs776746)*1和CYP3A4(rs2242480)*1G等位基因的快代谢型受试者与只携带CYP3A5(rs776746)*1或CYP3A4(rs2242480)*1G等位基因的正常代谢型受试者和不携带CYP3A5(rs776746)*1和CYP3A4(rs2242480)*1G等位基因的慢代谢受试者比较,D、c0/D差异具有统计学意义(P<0.05),其中快代谢型受试者的他克莫司D最高,慢代谢型受试者的他克莫司D最低。结论:检测CYP3A5(rs776746)和CYP3A4(rs2242480)基因多态性对肺移植患者术后使用他克莫司1年后他克莫司的个体化给药具有指导意义。     

CYP3A5~*3和CYP3A4~*18B基因多态性对肾移植患者环孢素药代动力学的影响

目的回顾性研究肾脏移植后1mon,CYP3A5*3和CYP3A4*18B基因多态性对CsA药代动力学参数的影响。方法采用PCR-RFLP方法分析了63名肾脏移植患者CYP3A5*3和CYP3A4*18B基因型;荧光偏正免疫法用于检测肾移植患者静脉全血中的CsA浓度。结果在63名肾移植患者中,CYP3A5*3和CYP3A4*18B突变等位基因发生频率分别为0.770(95CI:0.767～0.773),0.235(95CI:0.235～0.241),而且这些等位基因表现出完全连锁不平衡。在移植术后1mon内,携带CYP3A4*1/*1野生型纯合子患者的C0以及剂量校正谷血浓度(C0/D)均明显高于携带CYP3A4*1/*18B杂合子或CYP3A4*18B/*18B突变型纯合子患者(P<0.05,Mann-WhitneyUtest);CYP3A5*1/*1基因型组的给药剂量明显高于CYP3A5*1/*3或CYP3A5*3/*3基因型组(P=0.004<0.01,Kruakal-Wallistest);CYP34*18B和CYP3A5*3联合考虑,对于CYP3A5表达组,同样发现C0、C0/D在CYP3A4*1/*1组C0以及C0/D均明显高于CYP3A4*1/*18B或CYP3A4*18B/*18B组(P<0.05,Mann-WhitneyUtest);而其他药动学参数在CYP3A5*3及CYP3A4*18B各组间相比差异则没有统计学意义。结论CYP3A5*3和(或)CYP3A4*18B基因多态性对肾移植后1monCsA药代动力学有一定影响,移植前CYP3A5*3基因型的分析仍需进一步研究。     

CYP3A5/3A4多态性对肾移植患者术后早期他克莫司剂量的影响

目的：探索肾移植患者术后早期遗传因素与他克莫司（ FK506）个体化给药的规律,并探讨各单倍型患者在术后不同时间所需剂量的个体差异。方法：观察113例肾移植术后常规应用他克莫司+霉酚酸酯+泼尼松三联免疫抑制治疗的患者,记录术后早期（3、5、7和14 d）FK506全血谷浓度（ C0）和剂量（ D,每日每 kg 体重剂量）,测定每个患者CYP3A5及 CYP3A4基因多态性。采用酶联免疫吸附法（ELISA）监测患者术后 FK506的 C0,DNA 直接测序法测定患者CYP3A5*3、CYP3A4*18B 基因多态性。在此基础上,根据患者基因型进行分组,比较不同基因型患者 FK506的 C0、D 及C0／ D。结果：113例肾移植患者 CYP3A5*3和 CYP3A4*18B 突变等位基因发生的频率分别为73.0%和30.5%,各基因频率达到遗传平衡。CYP3A5不表达组（CYP3A5*3／*3）的 C0／ D 是 CYP3A5表达组（CYP3A5*1）的2.1~2.5倍（P ﹤0.05）;CYP3A4不表达组（CYP3A4*1／*1）的 C0／ D 是 CYP3A4表达组（CYP3A4*18B）的1.3~1.7倍（P ﹤0.05）;对于CYP3A5- CYP3A4单倍型,GG - GG 组的 C0／ D 是 AA - AA 组的2.0~2.8倍（P ﹤0.05）。各基因型患者达目标靶浓度的人数比例随术后时间延长逐步增加,而 AA - AA 组达靶浓度人数比例始终最少（ P ﹤0.05）。结论：CYP3A5*3和CYP3A4*18B基因多态性对肾移植术后 FK506的药动学有显著影响,肾移植术前可通过对患者单独进行 CYP3A5基因型的测定来确定术后早期 FK506初始剂量,从而实现个体化用药。     

Association study of ABCB1 and CYP3A5 gene polymorphisms with sirolimus trough concentration and dose requirements in Chinese renal transplant recipients

The objective of this study was to investigate the possible association of the ABCB1 gene C3435 T polymorphism and the CYP3A5 gene A6986G polymorphism with sirolimus (SRL) trough concentration and dose requirements in Chinese stable renal transplant recipients. Blood samples were collected from 105 healthy volunteers and 50 renal transplant patients, whose polymorphisms of the ABCB1 and CYP3A5 genes were determined by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP). Plasma concentrations of SRL were determined with HPLC. The allele frequencies of the ABCB1 mutation in Chinese healthy volunteers and renal transplant recipients were 51.0% and 44.0% (p>0.05), while the allele frequencies of the CYP3A5 mutation were 72.9% and 71.0% (p>0.05). The SRL concentration/dose ratio (C/D) in patients with CYP3A5 (*)3/(*)3 were significantly higher than that of those with (*)1 allele (p<0.05). However, no significant differences were observed between C/D and ABCB1 SNPs (p>0.05). These results confirm that when treated with a SRL-based therapy and low-dose steroids, patients carrying the CYP3A5(*)1 allele required significantly more SRL to achieve adequate blood trough concentrations. In patients with SRL-based therapy, genotyping of the CYP3A5 genes may help to optimize the SRL management in renal transplant recipients.     

CYP3A5 polymorphism affects the increase in CYP3A activity after living kidney transplantation in patients with end stage renal disease

AimsIt has been reported that cytochrome P450 (CYP)3A activity increases significantly in patients with end stage renal disease (ESRD) after kidney transplantation, with wide interindividual variability in the degree of increase. The aim of this study was to evaluate the influence of CYP3A5 polymorphism on the increase in CYP3A activity after living kidney transplantation, by measuring the plasma concentration of 4β‐hydroxycholesterol.MethodsThis prospective study recruited 22 patients with ESRD who underwent a first living kidney allograft transplantation, comprising 12 patients with CYP3A5*1 allele (CYP3A5*1/*1 or *1/*3) and 10 patients without CYP3A5*1 allele (CYP3A5*3/*3).ResultsNo significant difference in estimated glomerular filtration rate over time was observed between patients with the CYP3A5*1 allele and patients without the CYP3A5*1 allele, suggesting that the degrees of recovery in renal function after living kidney transplantation were similar in the two groups. However, plasma concentrations of 4β‐hydroxycholesterol on days 90 (57.1 ± 13.4 vs. 39.5 ± 10.8 ng ml⁻¹) and 180 (55.0 ± 14.5 vs. 42.4 ± 12.6 ng ml⁻¹) after living kidney transplantation were significantly higher in the presence of the CYP3A5*1 allele than in the absence of the CYP3A5*1 allele [P = 0.0034 (95% confidence interval of difference 6.55, 28.6) and P = 0.043 (95% confidence interval of difference 0.47, 24.8), respectively], suggesting that CYP3A activity may increase markedly associated with recovery of renal function in patients with the CYP3A5*1 allele.ConclusionsThese findings suggest that the presence of the CYP3A5*1 allele contributes to marked elevation of CYP3A activity associated with recovery of renal function after kidney transplantation.     

Tacrolimus Elimination in Four Patients With a CYP3A5*3/*3 CYP3A4*22/*22 Genotype Combination

Cytochrome P450 3A5 (CYP3A5) and cytochrome P450 3A4 (CYP3A4) are the predominate enzymes responsible for tacrolimus metabolism. The presence of CYP3A4 and CYP3A5 genetic variants significantly affects tacrolimus clearance and dose requirements. CYP3A5*3 is a loss‐of‐function variant resulting in no CYP3A5 enzyme production. CYP3A4*22 is a variant that reduces production of functional CYP3A4 protein. Caucasians commonly carry these variant alleles but are very rarely homozygous for both CYP3A5*3 and CYP3A4*22. This report describes four kidney transplant recipients who carry a rare genotype combination (CYP3A5*3/*3 and CYP3A4*22/*22). These patients were identified from a larger cohort of Caucasian kidney transplant recipients (n=1366). To understand the significance of this genotype combination on tacrolimus troughs and doses, we compared these patients to recipients without this combination. Patients homozygous for both variants are at risk for profound reductions in metabolism of CYP3A substrates. A 342% and a 90.6% increase in the median dose‐normalized trough was observed, when the CYP3A5*3/*3 and CYP3A4*22/*22 genotype combination was compared to the CYP3A5*1/*1 and CYP3A4*1/*1 genotype combination and the CYP3A5*3/*3 and CYP3A4*1/*1 genotype combination, respectively. These four individuals only required on average 2.5 mg/day of tacrolimus. Knowledge of these genotypes would be useful in selecting appropriate tacrolimus doses to avoid overexposure.     

CYP3A5、ABCB1基因多态性对中国肾移植患者服用他克莫司剂量和血药浓度的影响

目的：研究肾移植患者CYP3A5、ABCB1基因多态性对肾移植术后患者他克莫司（TAC）血药浓度及给药剂量的影响。方法：采集83例中国肾移植患者术后3个月内TAC的常规监测的谷浓度（C0）。测定受试者CYP3A5*3（rs776746）、ABCB1 1236C＞ T（rs1128503）、2677G＞ T/A（rs2032582）、3435C＞ T（rs1045642）位点的基因型,分析基因多态性对TAC的C0、剂量的影响。结果：患者CYP3A5、ABCB1基因型频率均符合Hardy-Weinberg平衡（P ＞ 0.05）。在移植后3个月期间,CYP3A5*3/*3型患者相较于携带*1等位基因患者,具有更高的C0和更低的剂量（P ＜ 0.05）。ABCB1 2677GG基因型的C0显著低于GT、GA、AA、TT、AT型（P ＜ 0.05）;3435CT型的C0显著高于CC、TT型（P ＜ 0.05）。根据ABCB1的单倍型进行分组,并与CYP3A5进行了联合分析,结果发现,发现CYP3A5*1/*1与*1/*3组与*3/*3组中,不同ABCB1单倍型对TAC血药浓度影响的差异无统计学意义。术后随时间延长,CYP3A5*3/*3型患者的TAC剂量逐步降低,而携带*1基因患者的剂量则呈增加趋势。结论：CYP3A5比ABCB1基因多态性对肾移植受者TAC血药浓度的影响更显著,若达到相同的血药浓度,CYP3A5*3/*3型患者每日所服用的剂量更低。根据CYP3A5基因型制定给药方案,有助于尽早达到浓度标准,达到精准治疗的目标。     

Pharmacokinetics of midazolam in CYP3A4- and CYP3A5-genotyped subjects

Objective We investigated whether differences in pharmacokinetics of midazolam, a CYP3A probe, could be demonstrated between subjects with different CYP3A4 and CYP3A5 genotypes.Methods Plasma concentrations of midazolam, and of total (conjugated + unconjugated) 1OH-midazolam, and 4OH-midazolam were measured after the oral administration of 7.5 mg or of 75 µg of midazolam in 21 healthy subjects.Results CYP3A5*7, CYP3A4*1E, CYP3A4*2, CYP3A4*4, CYP3A4*5, CYP3A4*6, CYP3A4*8, CYP3A4*11, CYP3A4*12, CYP3A4*13, CYP3A4*17 and CYP3A4*18 alleles were not identified in the 21 subjects. CYP3A5*3, CYP3A5*6, CYP3A4*1B and CYP3A4*1F alleles were identified in 20, 1, 4 and 2 subjects, respectively. No statistically significant differences were observed for the AUC_inf values between the different genotypes after the 75-µg or the 7.5-mg dose.Conclusion Presently, CYP3A4 and CYP3A5 genotyping methods do not sufficiently reflect the inter-individual variability of CYP3A activity.     

CYP3A4、3A5基因多态性对肾移植患者术后他克莫司浓度/剂量比值的影响

摘 要 目的:探讨CYP3A4*18B(82266G>A,rs2242480)、CYP3A5*3(6986A>G,rs776746)位点的基因多态性对肾移植术后服用他克莫司（FK506）用药的指导作用。方法: 采用PCR RFLP(聚合酶链反应 限制性片段长度多态性)方法对280名肾移植患者进行CYP3A4*18B、CYP3A5*3基因型检测,利用化学发光微粒子免疫分析技术（CMIA）检测肾移植患者FK506血浓度,比较不同基因型患者之间FK506血药谷浓度/剂量*体质量(C₀/D)比值。 结果:280例肾移植患者中,CYP3A4*18B和CYP3A5*3基因型的突变频率分别为29.1%和69.3%。CYP3A4*18B/*18B基因型肾移植患者术后1个月,3个月FK506的C₀及C₀/D值显著低于CYP3A4*1/*1、CYP3A4*1/*18B基因型（P<0.05）。CYP3A5*3/*3基因型肾移植患者术后7日,1个月FK506的C₀及C₀/D值显著高于CYP3A5*1/*1、CYP3A5*1/*3基因型（P<0.05）。将CYP3A4*18B和CYP3A5*3进行单倍体基因型组合分析,用药后15 d、1个月,GG-GG基因型组的C₀明显高于AA-GG基因型组（P<0.05）;用药后6月,GG-GG、GA-GG、GA-AG基因型组的C₀均明显高于AA GG基因型组（P<0.05）。结论: CYP3A4*18B和CYP3A5*3基因多态性对肾移植患者的FK506血药浓度及其C₀/D值有一定影响,患者在使用FK506前进行CYP3A4*18B和CYP3A5*3基因型检测,对预测FK506用药剂量有一定的指导作用。     

CYP3A5和MDR1基因型对尿毒症患者肾移植术后早期他克莫司血药浓度和肌酐水平的影响

目的 评价真实临床实践中CYP3A5(CYP3A5*3,6986A>G)及MDR1(C3435>T,G2677>T/A,C1236>T)基因多态性对尿毒症患者接受肾移植术后早期他克莫司血药浓度的影响及其最佳治疗浓度。方法 以入选2013～2017年单中心的131例首次肾移植术且术后以他克莫司为基础进行三联免疫治疗的患者为对象,开展回顾性研究,考察患者基因多态性对他克莫司的日剂量、血药浓度、血药浓度/剂量比值和肌酐水平的影响。结果 在维持他克莫司靶浓度（10～15 ng/ml）的前提下,肾移植术后4周内基因型为CYP3A5*3/*3(GG)肾移植受者的给药剂量低于基因型CYP3A5*1/*1(AA)和CYP3A5*1/*3(AG)。患者血药浓度在10～13 ng/ml内时,其血肌酐水平最接近正常值。结论 CYP3A5基因多态性影响肾移植受者他克莫司的血药浓度,未发现MDR1基因多态性对他克莫司血药浓度的影响。早期肾移植血药浓度控制在10～13 ng/ml时,患者移植肾功能最接近正常人肾功能水平。     

三氯乙烯对3种细胞色素P450酶基因表达的影响

目的 探讨三氯乙烯（Trichloroethylene,TCE)对人体淋巴细胞瘤细胞株（MCL-5）中3种细胞色素P450酶基因（CYP1A1、CYP2E1、CYP3A4）表达的影响,并研究剂量反应关系和时间反应关系,方法 用常规的细胞培养方法,0.5、1.0、1.5、2.0mmol/L TCE处理细胞12、24、48、72h。利用提纯RNA和cDNA的药盒,合成cDNA,然后逆转录聚合酶反应（RT-PCR）表达3种CYP450基因,以β-Actin作为内对照,分析不同处理剂量和时间时基因表达的强度。结果 在MCL-5细胞株中都有基本的表达,CYP1A1表达在用1.0、1.5、2.0mmol/LTCE处理48h后有被上调的趋势,而且上调趋势随处理时间延长耐加强;CYP2E1、CYP3A4表达不受TCE处理时间长短的影响。3种CYP450酶基因的表达受TCE剂量的影响。3随0.5mol/L,1.0、1.5、2.0mmol/L剂量的增加有上调的趋势,结论 TCE对CYP450酶系统中的CYP2E1、CYP1A1、CYP3A4基因有明显的诱导作用。这些基因被诱导后的结果。可能会导致相对应酶活性的增加,同时加强对TCE的代谢,使TCE的代谢产物增加。