CYP2D6基因多态性对帕罗西汀在中国健康人药动学影响

目的研究中国健康人CYP2D6基因多态性对帕罗西汀药动学的影响。方法使用PCR-RFLP方法将23位志愿者分为3组:CYP2D6*1/*1组(n=5),CYP2D6*1/*10组(n=7),CYP2D6*10/*10组(n=11)。给予帕罗西汀20 mg单剂量口服,收集给药后96 h内的一系列血样,用LC-MS/MS法测定帕罗西汀的血药浓度并做药动学分析。结果与CYP2D6*1/*1组药动学参数相比,CYP2D6*1/*10组t_(max)、t1/2和CYP2D6*10/*10组t_(max)无显著差异(P>0.05);CYP2D6*1/*10、CYP2D6*10/*10组的ρ_(max)、AUC_(0-96 h)、AUC_(0-∞)、CL(F)、Vd和CYP2D6*10/*10组t_(1/2)均有显著差异(P<0.05或P<0.01)。结论 CYP2D6*10等位基因突变能引起代谢表型的改变,影响帕罗西汀在健康人的体内代谢。     

CYP2C9基因多态性对苯溴马隆药动学的影响

目的研究健康人体内不同细胞色素P450(CYP)2C9基因多态性对苯溴马隆药动学的影响。方法采用PCR-RFLP方法对120例健康志愿者进行了CYP2C9基因多态性筛查,其中20例参加苯溴马隆药动学试验。用高效液相色谱法检测受试者体内苯溴马隆的药动学参数,分析不同的CYP2C9基因分型药动学参数的差异。结果 120例志愿者中筛选出9例CYP2C9*1/*3杂合型突变体、1例CYP2C9*3/*3纯合型突变体和110例CYP2C9*1/*1野生型个体。9例CYP2C9*1/*3、1例CYP2C9*3/*3突变型(突变型组)和10例CYP2C9*1/*1(野生型组)志愿者参加了苯溴马隆的药动学试验。CYP2C9*3的等位基因频率为7.5%。突变型组的ρmax、t1/2、AUC0-24均高于野生型组,而CL/F低于野生型组,差异均具有统计学意义(P<0.05)。苯溴马隆给药24 h后,CYP2C9*1/*1野生型、CYP2C9*1/*3杂合突变型和CYP2C9*3/*3纯合突变型志愿者尿酸清除较服药前分别增加了130%、90%和75%,血尿酸浓度较服药前分别减少了60%、43%和41%;突变型组与野生型组相比,差异具有统计学意义(P<0.05)。结论 CYP2C9基因多态性对苯溴马隆的代谢具有显著的影响,苯溴马隆在CYP2C9*3突变个体的代谢显著低于CYP2C9*1野生型个体,检测突变型个体对指导临床个体化用药具有重要意义。     

CYP450基因多态性对口服降糖药药动学的影响

介绍了近年来细胞色素P450酶系基因多态性对口服降糖药药动学影响的相关研究,重点指出CYP 2C9*3可能显著降低酶活性,降低药物清除率,升高血药浓度,从而可能改变药效,说明了依基因型调整药物剂量的个体化治疗的必要性。     

CYP2D6*10基因多态性与比索洛尔药动学关系研究

目的:研究CYP2D6*10不同基因型对健康志愿者体内比索洛尔药动学的影响。方法:采用实时荧光测序法分析CYP2D6*10基因型。将24例健康志愿者分为CC、CT、TT基因型3组(n=8),受试者单剂量口服富马酸比索洛尔片5 mg后,采用高效液相色谱法测定血药浓度。结果:CC、CT、TT 3种基因型受试者之间主要药动学参数t1/2、cmax、AUC0-32 h分别为(8.25±1.80)、(7.70±1.18)、(8.19±1.86)h,(41.69±11.22)、(37.69±6.53)、(43.14±5.85)μg/L,(394.38±104.70)、(380.04±84.04)、(414.08±104.40)μg·h/L。通过t检验,3种基因型之间无显著性差异(P>0.05)。结论:比索洛尔药动学在个体间的差异与CYP2D6*10基因型无相关性。     

高脂饮食及CYP3A4基因多态性对西地那非在健康中国受试者体内药动学的影响

目的探讨高脂饮食及CYP3A4*1G(rs2242480)基因多态性对西地那非中国健康人体药动学的影响。方法 32例健康男性受试者分别接受空腹服药试验和高脂餐后服药试验。受试者单次口服西地那非片100 mg,液相色谱-串联质谱(LC-MS/MS)法测定给药后西地那非的血药浓度,采用非房室模型法计算西地那非的药动学参数。直接测序法检测CYP3A4*1G的基因分型。用χ~2检验(Fisher确切概率法)分析突变等位基因的分布是否符合Hardy-Weinberg平衡,独立样本t检验比较空腹与高脂餐后及各基因型个体的药动学参数。结果 31例完成了空腹服药试验,32例受试者完成了高脂餐后服药试验。与空腹状态相比,高脂饮食后t_(max)约推迟60 min,ρ_(max)约下降28%(P<0.05);t_(1/2)、AUC_(0-24)及AUC_(0-∞)均无显著差异(P>0.05)。完成基因分型的31例受试者中,野生型(CYP3A4*1/*1)17例,突变型(CYP3A4*1/*1G和CYP3A4*1G/*1G)共14例,突变等位基因的分布符合Hardy-Weinberg平衡(P>0.05),两组之间西地那非的药动学参数无显著差异(P>0.05)。结论高脂饮食导致西地那非的吸收速率减慢,但不影响其吸收程度;CYP3A4*1G基因多态性对西地那非药动学无明显影响。     

CYP2C19基因型对雷贝拉唑在健康人中药动学的影响

目的:研究雷贝拉唑在体内的代谢与CYP2C19酶的相关性,预测CYP2C19基因多态性对雷贝拉唑抑酸效应的影响。方法:采用开放、对照研究。根据PCR-RFLP方法确定的CYP2C19基因型将36例志愿者分为2组,CYP2C19强代谢型(EMs)组(n=24)及弱代谢型(PMs)组(n=12)。给予雷贝拉唑20mg单剂量口服,收集服药后12h的血样,用高效液相色谱(HPLC)法测定雷贝拉唑及其代谢产物硫醚雷贝拉唑、去甲基硫醚雷贝拉唑的血药浓度并作药动学分析。结果:硫醚雷贝拉唑的tmax和t1/2为EMs组(3.0±s0.6)h和(1.9±0.4)h;PMs组(3.6±0.9)h和(3.0±0.8)h,P<0.05和P<0.01,雷贝拉唑、硫醚雷贝拉唑以及去甲基硫醚雷贝拉唑的cmax,AUC,Cl/F2组差异均无显著意义。结论:雷贝拉唑的代谢主要不依赖于CYP2C19酶。     

CYP2D6*10基因多态性与泮托拉唑药动学关系研究

目的:研究泮托拉唑在不同CYP2D6*10基因型健康志愿者体内的药动学。方法:24名健康志愿者分为CC组、CT组、TT组;应用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)分析CYP2D6*10基因型。受试者均口服泮托拉唑肠溶胶囊(40mg)后,采用高效液相色谱法测定血药浓度。结果:CC组、CT组、TT组的t1/2分别为(1.78±0.34)、(1.51±0.64)、(2.05±0.37)h,cmax分别为(3.20±0.82)、(3.29±0.74)、(3.13±0.79)mg/L,AUC0-12h分别为(11.18±3.94)、(11.37±4.66)、(14.31±4.77)mg·h/L。通过t检验,t1/2、cmax、AUC0-12h3种基因型之间的差异均无统计学意义(P>0.05)。结论:泮托拉唑药动学在个体间的差异与CYP2D6*10基因型可能不相关。     

乳腺癌患者CYP2D6基因多态性对他莫昔芬疗效影响的系统评价

目的 系统评价CYP2D6基因多态性对他莫昔芬(Tam)参与治疗乳腺癌患者的无病生存期(DFS)和总生存期(OS)的影响,评价其作为Tam疗效预测指标及指导个体化用药的可行性。方法 计算机检索Cochrane Library、Pub Med、Embase、中国知网、中国生物医学文献数据库、维普全文数据库、万方等数据库,并手工检索相关文献,查找关于CYP2D6基因型及Tam治疗乳腺癌患者以DFS、OS为结局指标的文献。检索时间为1995年1月至2016年10月。采用Rev Man5.3软件进行Meta分析。结果 共纳入文献26篇,其中22篇为英文文献,4篇为中文文献,共包含12 602例患者。Meta分析结果显示,与未携带CYP2D6突变基因患者相比,携带CYP2D6突变基因的患者具有更短的DFS[HR=1.44,95%CI(1.18~1.76),P=0.000 3]和OS[HR=1.20,95%CI(1.07~1.35),P=0.002]。结论 乳腺癌患者经Tam治疗后,携带CYP2D6突变基因患者比未携带CYP2D6突变基因的患者具有更短的DFS和OS,可在临床使用Tam治疗前测定CYP2D6基因多态性,促进个体化给药。     

CYP2D6在印度卡纳塔克邦和安得拉邦人群中的遗传多态性(英文)

AIM: To study the prevalence of cytochrome P-450 2D6 (CYP2D6) polymorphism in Kamataka ( KA) and Andhra Pradesh (AP) population. METHODS: Two hundred and eleven healthy human volunteers participated in the study (100 from KA and 111 from AP). At bed time, after voiding their bladder, the volunteers ingested 30 mg of dextromethorphan hydrobromide (DM). Urine samples were collected for 8 h. DM and its metabolite dextrorphan ( DT) were estimated in the urine using HPLC. The metabolic ratio (DM/DT) was used for phenotyping. RESULTS: The prevalence of poor metabolisers (PM) in KA is 4 % and AP is 1.8 %. CONCLUSION: The frequency of PM phenotype in South Indian population is in between the Western and Oriental population.     

A novel polymorphism in ABCB1 gene, CYP2B6*6 and sex predict single-dose efavirenz population pharmacokinetics in Ugandans

AIMS

Efavirenz exhibits pharmacokinetic variability causing varied clinical response. The aim was to develop an integrated population pharmacokinetic/pharmacogenetic model and investigate the impact of genetic variations, sex, demographic and biochemical variables on single-dose efavirenz pharmacokinetics among Ugandan subjects, using nonmem.

METHODS

Efavirenz plasma concentrations (n= 402) from 121 healthy subjects were quantified by high-performance liquid chromatography. Subjects were genotyped for 30 single nucleotide polymorphisms (SNPs), of which six were novel SNPs in CYP2B6, CYP3A5 and ABCB1. The efavirenz pharmacokinetics was described by a two-compartment model with zero- followed by first-order absorption.

RESULTS

Apparent oral clearance (95% confidence interval) was 4 l h l⁻¹ (3.5, 4.5) in extensive metabolizers. In the final model, incorporating multiple covariates, statistical significance was found only for CYP2B6*6 and CYP2B6*11 on apparent oral clearance as well as ABCB1 (rs3842) on the relative bioavailability. Subjects homozygous for CYP2B6*6 (G516T, A785G) and *11 displayed 21 and 20% lower apparent oral clearance, respectively. Efavirenz relative bioavailability was 26% higher in subjects homozygous for ABCB1 (rs3842). The apparent peripheral volume of distribution was twofold higher in women compared with men.

CONCLUSIONS

The model identified the four factors CYP2B6*6, CYP2B6*11, a novel variant allele in ABCB1 (rs3842) and sex as major predictors of efavirenz plasma exposure in a healthy Ugandan population after single-dose administration. Use of mixed-effects modelling allowed the analysis and integration of multiple pharmacogenetic and demographic covariates in a pharmacokinetic population model.     

Effect of CYP2B6*6 and CYP2C19*2 genotype on chlorpyrifos metabolism

Chlorpyrifos (CPF) is a widely used organophosphorus (OP) pesticide. CPF is bioactivated by cytochrome P450s (CYPs) to the potent cholinesterase inhibitor chlorpyrifos oxon (CPF-O) or detoxified to 3,5,6-trichloro-2-pyridinol (TCPy). Human CYP2B6 has the highest reported Vmax)/Km (intrinsic clearance--CL(int)) for bioactivation while CYP2C19 has the highest reported CL(int) for detoxification of CPF. In this study, 22 human liver microsomes (HLMs) genotyped for common variants of these enzymes (CYP2B6*6 and CYP2C19*2) were incubated with 10 μM and 0.5 μM CPF and assayed for metabolite production. While no differences in metabolite production were observed in homozygous CYP2C19*2 HLMs, homozygous CYP2B6*6 specimens produced significantly less CPF-O than wild-type specimens at 10 μM (mean 144 and 446 pmol/min/mg, respectively). This correlated with reduced expression of CYP2B6 protein (mean 4.86 and 30.1 pmol/mg, for CYP2B6*6 and *1, respectively). Additionally, CYP2B6*1 and CYP2B6*6 were over-expressed in mammalian COS-1 cells to assess for the first time the impact of the CYP2B6*6 variant on the kinetic parameters of CPF bioactivation. The Vmax for CYP2B6*6 (1.05×10? pmol/min/nmol CYP2B6) was significantly higher than that of CYP2B6*1 (4.13×10? pmol/min/nmol CYP2B6) but the K(m) values did not differ (1.97 μM for CYP2B6*6 and 1.84 μM for CYP2B6*1) resulting in CL(int) rates of 53.5 and 22.5 nL/min/nmol CYP2B6 for *6 and *1, respectively. These data suggest that CYP2B6*6 has increased specific activity but reduced capacity to bioactivate CPF in HLMs compared to wild-type due to reduced hepatic protein expression, indicating that individuals with this genotype may be less susceptible to CPF toxicity.     

CYP2D6^＊10B基因型对中国人普罗帕酮对映体药动学的影响

AIM: To study the relationship between genotype of CYP2D6*10B and pharmacokinetics of propafenone enantiomers. METHODS: Genotype of 17 healthy Chinese HAN subjects was determined by an allele specific amplification method. The blood samples (0-15 h) of the subjects were taken after oral administration of a single dose (400 mg) of propafenone hydrochloride. Concentrations of propafenone enantiomers in plasma were measured by a reverse-phase HPLC with precolumn derivatization. RESULTS: Seventeen subjects characterized for CYP2D6*10B genotype included (*1/*1) (n=4), (*1/*10) (n=5) and (*10/*10) (n=8). The metabolic ratios (lg MR) of the three genotypes were -2.68+/-0.23, -2.2+/-0.7, and -1.1+/-0.5, respectively. The AUC of the three groups were (1534+/-334), (1891+/-793), (3171+/-1075) microg.h.L(-1) for S-enantiomer and (1136+/-345), (1467+/-817), (2277+/-745) microg.h.L(-1) for R-enantiomer, respectively. The AUC of propafenone enantiomers in *10/*10 is about 1.5-2 times of that of *1/*10 group or *1/*1 group, and the CL of both enantiomers in *10/*10 is only half of that of *1/*10 group or *1/*1 group (P<0.05). CONCLUSION: CYP2D6*10B alleles induce the declined activity of CYP2D6 and impair the metabolism of propafenone.     

中国人群CYP2D6基因多态性对美托洛尔药代动力学的影响

目的：研究中国人群CYP2D6基因多态性对美托洛尔药代动力学的影响。方法：使用基因芯片技术测定中国健康志愿者CYP2D6的基因型,按照分型结果将志愿者分为四组,第1组：CYP2D6＊2W＊10W,第2组：CYP2D6＊2H＊10W或CYP2D6＊2M＊10W,第3组：CYP2D6＊2M＊10H,第4组：CYP2D6＊2M＊10M,每组筛选10人,共40人。各组志愿者单次口服100mg美托洛尔后,使用HPLC方法测定血和尿中美托洛尔及其代谢产物α-羟基美托洛尔（HM）的浓度,研究其在不同基因型志愿者体内的药代过程。结果：第2组美托洛尔及其HM的主要药动学参数与第1组相比均没有统计学差异。第3组美托洛尔的t1/2、AUC、Cmax显著高于第1组（P〈0.05）;而HM的t1/2延长47.3%,AUC降低56.0%（P〈0.05）。第4组美托洛尔的t1/2、AUC、Cmax均显著高于第1组（P〈0.05）和第3组（P〈0.05）;HM的t1/2、AUC、Cmax与第1组和第3组相比均有统计学差异（P〈0.05）,且呈现基因剂量效应。第3组和第4组的口服清除率和肾清除率均低于第1组,而0-24h代谢比率分别为第1组的1.82倍和3.96倍。结论：CYP2D6＊2对于美托洛尔的药代动力学过程没有影响;但CYP2D6＊10可降低酶活性,且CYP2D6＊10纯合子变异比杂合子变异对美托洛尔药代动力学的影响更大,呈现基因剂量效应。     

中国人群细胞色素P4502D6基因多态性对曲马多药代动力学的影响

目的 研究中国人群CYP2D6基因多态性对曲马多(镇痛药)药代动力学的影响.方法 不同基因型中国健康志愿者随机分为4组:第1组CYP2D6*2W*10W,第2组:CYP2D6*2M*10W,第3组:CYP2D6*2M*10H,第4组:CYP2D6*2M*10M.各组单次口服曲马多100 mg后,用高效液相色荧光检测法测定血和尿中曲马多及其M1代谢产物O-去甲基曲马多(M1)的浓度,研究不同基因型对曲马多药代动力学的影响.结果 第2组曲马多及其M1的主要药代动力学参数与第1组相比没有显著性差异;第3组与第1组、第4组与第1组、第4组与第3组比较,主要药代动力学参数均有显著性差异(P<0.05),且呈基因剂量效应.结论 CYP2D6*2对于曲马多的药代动力学过程没有影响;但CYP2D6*10可降低酶活性,且CYP2D6*10纯合子变异较杂合子变异对曲马多药代动力学的影响更大,呈基因剂量效应.     

Effects of the CYP2B6*6 allele on catalytic properties and inhibition of CYP2B6 in vitro: implication for the mechanism of reduced efavirenz metabolism and other CYP2B6 substrates in vivo

The mechanism by which CYP2B6*6 allele alters drug metabolism in vitro and in vivo is not fully understood. To test the hypothesis that altered substrate binding and/or catalytic properties contribute to its functional consequences, efavirenz 8-hydroxylation and bupropion 4-hydroxylation were determined in CYP2B6.1 and CYP2B6.6 proteins expressed without and with cytochrome b5 (Cyt b5) and in human liver microsomes (HLMs) obtained from liver tissues genotyped for the CYP2B6*6 allele. The susceptibility of the variant protein to inhibition was also tested in HLMs. Significantly higher V(max) and K(m) values for 8-hydroxyefavirenz formation and ～2-fold lower intrinsic clearance (Cl(int)) were noted in expressed CYP2B6.6 protein (-b5) compared with that of CYP2B6.1 protein (-b5); this effect was abolished by Cyt b5. The V(max) and Cl(int) values for 4-hydroxybupropion formation were significantly higher in CYP2B6.6 than in CYP2B6.1 protein, with no difference in K(m), whereas coexpression with Cyt b5 reversed the genetic effect on these kinetic parameters. In HLMs, CYP2B6*6/*6 genotype was associated with markedly lower V(max) (and moderate increase in K(m)) and thus lower Cl(int) values for efavirenz and bupropion metabolism, but no difference in catalytic properties was noted between CYP2B6*1/*1 and CYP2B6*1/*6 genotypes. Inhibition of efavirenz 8-hydroxylation by voriconazole was significantly greater in HLMs with the CYP2B6*6 allele (K(i) = 1.6 ± 0.8 μM) than HLMs with CYP2B6*1/*1 genotype (K(i) = 3.0 ± 1.1 μM). In conclusion, our data suggest the CYP2B6*6 allele influences metabolic activity by altering substrate binding and catalytic activity in a substrate- and Cyt b5-dependent manner. It may also confer susceptibility to inhibition.