基因多态性对华法林抗凝治疗维持剂量的影响

目的研究中国汉族人群细胞色素P450酶4F2基因(cytochrome P-450 4F2.CYP4F2)多态性分布,并探讨其与华法林抗凝维持剂量的关系。方法采集112例心脏机械瓣膜置换术后服用华法林抗凝已达稳定剂量、凝血酶原时间国际标准化比值INR在目的范围(1.5-2.5)病人的外周血,采用用聚合酶链式反应(polymerase chain reaction,PCR)基因测序的方法检测CYP4F2 rs2108622基因位点的基因型和等位基因频率,探讨华法林抗凝维持剂量与该基因多态性的关系。结果在所有的样本中,CYP4F2 rs2108622基因共检出C(73.1%)和T(26.9%)2种等位基因,检出基因有CC、TT和CT 3种基因型,其基因频率分别为54.1%、41.2和4.7%,人群中CYP4F2 rs2108622基因多态性分布在性别和年龄上无差异;TT基因型患者所需华法林维持剂量最高(4.7±0.99)mg/d,其次为CT基因型患者(3.70±0.85)mg/d,最少的是CC基因型患者(2.46±0.75)mg/d。结论中国汉族人群CYP4F2 rs2108622基因位点具有遗传多态性,其基因型在华法林抗凝治疗中具有重要指导意义。     

基因多态性对华法林谷浓度及维持剂量的影响

目的 探讨VKORC1(-1639G/A)、CYP2C9*3、CYP4F2(rs2108622) 和CYP2C19*2 基因多态性在中国心房颤动群体中的表达,分析其对房颤患者华法林谷浓度及维持剂量的影响。 方法 收集75例房颤患者的华法林血样,采用HPLC-UV法测定其谷浓度,PCR-RFLP法检测VKORC1(-1639G/A)、CYP2C9*3、CYP4F2(rs2108622)和CYP2C19*2基因分型。明确基因多态性对华法林谷浓度及维持剂量的影响。结果 华法林稳态谷浓度在0.5~<1.0μg?mL-1 、1.0~2.0μg?mL-1 及超过2.0μg?mL-1范围时,其临床有效率（69.23%,82.6%,63.41%）显著高于0. 5μg?mL-1以下浓度范围(48.39%)（P<0.05）,且0.5~<1.0μg?mL-1 及超过2.0μg?mL-1浓度范围华法林的临床有效率相近（P>0.05）。VKORC1(-1639G/A)、CYP2C9*3、CYP4F2(rs2108622) 和CYP2C19*2等位基因频率分别为8.65%、7.35%、20%、30%。VKORC1位点AA型、CYP4F2位点CC型患者华法林稳态谷浓度分别低于AG/GG及 CT/TT型患者（P<0.01）,而CYP2C9*3、CYP2C19*2各基因型间对华法林稳态谷浓度无显著差异（P>0.05）。携带AG/GG、CT/ TT型和野生型（*1/*1）基因型的患者,华法林维持剂量分别高于携带AA型、CC型和杂合型（*1/*3）的患者（P <0.01）,而CYP2C19*2各基因型间与华法林维持剂量无显著差异（P >0.05）。结论 VKORC1(-1639G/A)、CYP2C9*3、CYP4F2(rs2108622) 和CYP2C19*2基因多态性显著影响房颤患者华法林的维持剂量,且VKORC1(-1639G/A)、CYP4F2(rs2108622)基因多态性与房颤患者华法林谷浓度密切相关。     

基因与临床因素对华法林剂量的影响研究

目的:探讨中国汉族人群相关基因多态性以及患者临床因素对华法林剂量的影响。方法:采用限制性片段长度多态性技术和碱基淬灭探针技术,检测197名心脏机械瓣膜置换术后患者的VKORC1rs9923231、CYP2C9rs1057910以及CYP4F2rs2108622单核苷酸多态性,结合患者临床特征,分析对华法林剂量的影响。结果:VKORC1rs9923231、CYP2C9rs1057910和CYP4F2rs2108622基因多态性及年龄、体质量对华法林剂量的影响在统计学上有显著性差异(P<0.05),并解释了45.2%的华法林剂量差异。结论:中国汉族人群VKORC1rs9923231、CYP2C9rs1057910和CYP4F2rs2108622以及体质量和年龄都是影响华法林剂量的因素。     

北方地区老年患者VKORC1、CYP2C9、CYP4F2基因多态性对华法林抗凝效果的影响

目的:观察VKORC1、CYP2C9、CYP4F2基因多态性对北方地区机械瓣膜置换术后老年患者(60~75岁)华法林抗凝作用的影响。方法:研究纳入68例在北京安贞医院接受机械瓣膜置换术后华法林抗凝治疗的北方地区老年患者,同期入组68例接受瓣膜置换术后中青年患者(18~59岁),用Illumina SNP Golden Gate芯片技术检测患者VKORC1、CYP2C9、CYP4F2单核苷酸多态位点,随机抽取20%样本用Sanger法直接测序验证,统计分析各组患者华法林抗凝指标差异和老年组患者3种基因位点多态性与华法林稳定剂量的相关性。结果:136例患者VKORC1 rs9923231、CYP2C9 rs1057910、CYP4F2 rs2108622基因分布符合遗传平衡,老年组患者华法林日均稳定剂量(2.89±1.00)mg·d~(-1)显著低于中青年组(3.29±0.90)mg·d~(-1)(P<0.05)。老年患者携带VKORC1 rs9923231 CT突变型患者华法林稳定剂量(3.56±0.89)mg·d~(-1)显著高于TT纯合型患者(2.72±0.96)mg·d~(-1)(P<0.01)。老年组CYP2C9、CYP4F2各基因型组间华法林剂量无统计学差异(P>0.05)结论:老年患者服用华法林剂量明显减低,建议老年患者服用华法林时考虑检测VKORC1基因。     

VKORC1、CYP2C9、CYP4F2、EPHX1基因多态性对华法林剂量的影响

目的:探讨中国汉族人群VKORC1、CYP2C9、CYP4F2和EPHX1基因多态性对华法林剂量的影响。方法:采用限制性片段多态性技术和碱基淬灭探针技术检测197名心脏机械瓣膜置换术后患者的VKO RC1-1639G>A、CYP2C9 1075A>C、CYP4F2 rs2108622和EPHX1 rs2292566的基因多态性,结合患者的临床特征,分析各因素对华法林剂量的影响。结果:VKO RC1-1639G>A、CYP2C9 1075A>C、CYP4F2 rs2108622、EPHX1 rs2292566基因多态性以及体重和年龄分别解释了30.2%、7.0%、2.8%、3.6%、1.9%和1.7%的华法林个体剂量差异,多因素联合可解释46.7%的华法林个体剂量差异。结论:VKORC1-1639G>A和CYP2C9 1075A>C基因多态性是影响华法林稳定剂量重要的遗传因素;CYP4F2 rs2108622和EPHX1 rs2292566基因多态性以及年龄、体重对华法林的稳定剂量有影响,但较小。     

CYP2C9*3和CYP4F2 rs2108622基因多态性对中国华法林治疗患者过度抗凝和出血并发症的影响:一项队列研究

本研究通过回顾性队列研究,明确CYP2C9*3和CYP4F2 rs2108622基因多态性对华法林治疗相关的过度抗凝和出血并发症的影响.共纳入196例患者,其中男性80例,平均年龄50.8±10.7岁,平均随访26.9±11.8个月.患者行心脏瓣膜置换术后且服用华法林3个月以上,目标国际标准化比值(INR)控制在1.8...     

基因多态性对华法林剂量影响的研究进展

目的:了解基因多态性对华法林剂量的影响以及其在临床的应用研究,以期为华法林的精准用药提供参考。方法:查阅近年来国内外相关文献,对华法林基因多态性以及其在临床的应用研究进行归纳和总结。结果与结论:影响华法林剂量的主要基因为细胞色素P450(CYP)2C9和维生素K氧化物还原酶复合体1(VKORC1)。华法林主要由CYP2C9酶完成代谢,与其代谢最密切的突变型为CYP2C9*2和CYP2C9*3。携带CYP2C9*2、CYP2C9*3等位基因的患者比野生型CYP2C9*1/*1患者有更高的过度抗凝和出血风险,提示携带CYP2C9*2、CYP2C9*3等位基因的患者所需华法林的剂量低于野生型CYP2C9*1/*1患者。VKORC1的酶活性直接影响华法林的抗凝效果,VKORC1基因与华法林早期治疗的影响较大。CYP4F2、γ-谷氨酰基羟化酶(GGCX)、载体蛋白E(APOE)、微粒体环氧化物水纤酶编码基因(EPHX1)等基因与华法林的剂量均呈现一定的相关性。华法林基因检测的临床应用主要依据FDA建议的基因多态性与华法林初始剂量对照表和剂量计算公式,但与华法林的给药剂量相关的两项临床研究结果并不一致,检测基因并结合计算公式将华法林应用于临床是否具有意义仍存在争议。     

细胞色素P450酶4F2基因多态性对华法林剂量影响的研究

目的：探讨中国苏南地区心脏机械瓣膜置换术后汉族人群细胞色素P450酶4F2（CYP4F2）基因rs2108622多态性对华法林剂量的影响,为以后利用基因多态性指导临床合理用药提供进一步理论依据。方法：采用碱基淬灭探针技术,检测197名心脏机械瓣膜置换术后患者的CYP4F2 rs2108622的基因型,分析与华法林剂量的相关性及影响。结果：CYP4F2 rs2108622基因多态性检测有115例CC型纯合子,73例CT型杂合子,9例TT型突变纯合子;等位基因频率为C 76.9%,T 23.1%;CC型患者华法林的平均稳定剂量为（2.51&#177;0.82）mg&#183;d^-1,CT型为（2.74&#177;0.96）mg&#183;d^-1,TT型为（3.20&#177;1.22）mg&#183;d^-1,采用方差分析方法得到各组间华法林剂量差异P值小于0.05,有显著性差异。结论：在苏南地区心脏机械瓣膜置换术后汉族人群中,CYP4F2 rs2108622基因多态性与华法林剂量相关性有显著性差异,对华法林剂量有影响。     

POR基因多态性与华法林维持剂量关系的研究

目的探讨POR基因多态性与华法林维持剂量的相关性。方法共纳入185例中国汉族人工心脏机械瓣膜置换术患者,采用Sequenom MassARRAYSystem检测VKORC1及POR相关SNPs,采用PCR-RFLP法检测CYP2C9*3基因型。采用ANOVA或t检验考察目的 SNPs与患者华法林维持剂量的关系。结果在CYP2C9*1*1携带者中,POR rs17685 T等位基因携带者(TT型和CT型)华法林维持剂量明显高于CC型携带者(3.50±1.07)mg·d-1vs(3.14±0.94)mg·d-1,P=0.03。在CYP2C9*1*1及VKORC1 rs9934438 GA/GG携带者中,POR rs17685 T等位基因携带者(TT型和CT型)的华法林维持剂量明显高于CC型携带者(4.76±0.90)mg·d-1vs(4.08±1.03)mg·d-1,P=0.04。未发现POR rs2868177与华法林维持剂量存在相关性。结论在中国汉族人工心脏机械瓣膜置换术患者中,POR rs17685 T突变与华法林剂量上调相关,该基因型检测将有助于指导华法林的临床合理应用。     

CYP2C9和VKORC1基因多态性对心脏瓣膜置换术后华法林维持剂量和抗凝效果的影响

目的:探讨CYP2C9和VKORC1基因多态性对华法林稳定维持剂量和抗凝治疗的影响,为建立心脏机械瓣膜置换术后患者的华法林个体化给药模型提供依据。方法:应用聚合酶链式反应-限制性片段长度多态性(PCR-RFLP)方法检测福州地区119例心脏机械瓣膜置换术后患者CYP2C9*3、CYP2C9-65G/C和VKORC1-1639A/G基因多态性。收集性别、年龄、体质量信息,同时记录华法林的稳定维持剂量、达标天数,观察抗凝过量、不良反应等指标。结果:CYP2C9*3和CYP2C9-65G/C基因型与低华法林维持剂量相关,VKORC1-1639A/G基因型与高华法林维持剂量相关。CYP2C9杂合体组患者抗凝过量危险性增加,但出血的危险性没有增加;携带CYP2C9和VKORC1突变等位基因的患者,抗凝达稳态时间延长。结论:患者用药前进行CYP2C9和VKORC1基因型检查,预测华法林用药剂量,可减少抗凝过量的发生,缩短剂量调整的时间。     

CYP4F2、CYP2C9和VKORC1基因多态性对中国汉族非瓣膜性房颤患者使用华法林剂量的影响

目的：探讨CYP4F2等基因多态性及临床特征对中国汉族非瓣膜性房颤患者华法林剂量的影响。方法：采用连接酶检测反应（LDR）检测CYP2C9＊3、VKORC11173和CYP4F2的基因型。多元线性回归分析CYP4F2等基因多态性及临床特征对中国汉族非瓣膜性房颤患者华法林剂量个体差异的影响。结果：CYP4F2TT患者的华法林剂量显著高于野生型患者（[3.04±0.98）mgvs.（2.60±0.84）mg,P=0.034）];CYP2C9＊3、VKORC11173和CYP4F2的基因多态性、年龄、体重、血栓史、联合应用胺碘酮以及β受体阻滞药解释了51.7%的华法林剂量个体差异,其中CYP4F2的基因多态性的贡献率为4.8%。结论：CYP4F2的基因多态性对中国汉族非瓣膜性房颤患者的华法林剂量有显著影响;基于临床特征与基因多态性的个体化给药方案可能有助于进一步提高非瓣膜性房颤患者的抗凝安全性。     

华法林抗凝个体化治疗研究进展

华法林是临床使用最多的口服抗凝药,其治疗窗窄,剂量个体差异大,容易发生出血或栓塞的风险,如何准确地调整华法林剂量一直是其抗凝治疗的关键及研究热点。多种因素均会影响华法林剂量,尤其是遗传因素（主要是CYP2C9、VKORC1及CYP4F2基因）。近十年来,基于药物基因组学的剂量预测模型和药代动力学药效学的快速发展,为华法林个体化治疗提供了新的契机。该文结合国内外各种华法林稳定剂量预测模型研究,总结影响华法林剂量相关因素的最新研究进展,旨在为华法林个体化治疗提供参考和指导依据。     

Influence of CYP4F2 rs2108622 (V433M) on warfarin dose requirement in Asian patients

Warfarin exhibits wide interpatient variability in dosing requirements. Recent studies have shown a novel polymorphism (rs2108622, V433M) in the CYP4F2 gene to be associated with variability in warfarin requirements in Caucasians. The purpose of this study was to evaluate the impact of rs2108622 on warfarin dose requirements in the Asian population. The mean warfarin dose was found to be significantly lower in patients carrying homozygous wild-type allele CC when compared with patients carrying variant alleles CT and TT (CC vs CT+TT: 3.0 mg/day vs 3.75 mg/day, p = 0.033). In patients harboring VKORC1 diplotypes associated with low warfarin requirements, a linear regression model which included age, weight, CYP2C9 and CYP4F2 variants accounted for 38% of the variability in warfarin dose. Approximately 11% of the dose variation was explained by CYP4F2 rs2108622 (p = 0.004). The influence of rs2108622 in patients harboring VKORC1 diplotypes associated with high warfarin requirements was not significant. This study suggests that CYP4F2 rs2108622 may significantly affect warfarin dose requirements in carriers of VKORC1 low-dose-associated diplotypes.     

CYP4F2 rs2108622: a minor significant genetic factor of warfarin dose in Han Chinese patients with mechanical heart valve replacement

AIMS

The objective of this study was to assess the effect of the CYP4F2 on the daily stable warfarin dose requirement in Han Chinese patients with mechanical heart valve replacement (MHVR).

METHODS

From March 2007 to November 2008, 222 Han Chinese MHVR patients were recruited in our study. VKORC1 3673G>A, 5417G>T, CYP2C9*3 and CYP4F2 rs2108622 were genotyped by using the polymerase chain reaction restriction fragment length polymorphism method (PCR-RFLP). Polymorphisms of VKORC1 9041G>A were detected by direct sequencing. Multiple linear regression analysis was used to investigate the contribution of CYP4F2.

RESULTS

The CYP4F2 rs2108622 CT/TT group took a significantly higher stable warfarin dose (3.2 mg day⁻¹) than the CC group (2.9 mg day⁻¹, 95% CI 0.2, 1.0, P= 0.033). The multiple linear regression model included VKORC1 3673G>A, CYP2C9, CYP4F2 genotypes and clinical characteristics. The model could explain 56.1% of the variance in stable warfarin dose in Han Chinese patients with MHVR. CYP4F2 contributed about 4% to the variance in the warfarin dose. There was no variation in the SNPs of VKORC1 5417G>T.

CONCLUSION

CYP4F2 is a minor significant factor of individual variability in the stable warfarin dose in Han Chinese patients with MHVR. The effect of CYP2C9 and VKORC1 genotypes on variability in the stable warfarin dose had also been confirmed.     

Impact of Genetic Factors (CYP2C9, VKORC1 and CYP4F2) on Warfarin Dose Requirement in the Turkish Population

Warfarin has a narrow therapeutic index and displays marked person‐to‐person variation in dose requirement. Functional polymorphisms at candidate genes can therefore offer utility as biomarkers to individualize warfarin treatment. The main objective of this study was to determine whether and to what extent variability in warfarin dose requirements was determined by polymorphisms in CYP2C9, VKORC1, CYP4F2 (rs2108622) and EPHX1 (rs2292566) in the Turkish population. Patients (n = 107) who had stable doses and international normalized ratio (INRs) at their last three consecutive visits were registered. Their demographic factors, concurrent medications, warfarin‐related bleedings or thromboembolisms, smoking, alcohol intake and weekly green vegetable consumption were recorded. From a blood sample, DNA was isolated and genotyped by real‐time PCR for polymorphisms of CYP2C9, VKORC1, CYP4F2 and EPHX1. A regression analysis was used to determine the independent effects of genetic and non‐genetic factors on warfarin dose optimization. In our study, in addition to age, genetic variants of CYP2C9, VKORC1 and CYP4F2 were found to be significant predictor variables for the maintenance dose for warfarin, explaining 39.3% of dose variability. VKORC1 and CYP2C9 genotypes remain predictor variables of the warfarin dose, and we first found that CYP4F2 (rs2108622) contributes to dose variability in the Turkish population as well. These observations may be of benefit to future translation research with a view to global personalized medicine in regions hitherto understudied such as the Turkish population so as to rationalize initial warfarin dose and reduce the burden of frequent INR measurements.     

Role of pharmacogenomics in the management of traditional and novel oral anticoagulants

Warfarin is the most commonly prescribed oral anticoagulant. However, it remains a difficult drug to manage mostly because of its narrow therapeutic index and wide interpatient variability in anticoagulant effects. Over the past decade, there has been substantial progress in our understanding of genetic contributions to variable warfarin response, particularly with regard to warfarin dose requirements. The genes encoding for cytochrome P450 (CYP) 2C9 (CYP2C9) and vitamin K epoxide reductase complex subunit 1 (VKORC1) are the major genetic determinants of warfarin pharmacokinetics and pharmacodynamics, respectively. Numerous studies have demonstrated significant contributions of these genes to warfarin dose requirements. The CYP2C9 gene has also been associated with bleeding risk with warfarin. The CYP4F2 gene influences vitamin K availability and makes minor contributions to warfarin dose requirements. Less is known about genes influencing warfarin response in African-American patients compared with other racial groups, but this is the focus of ongoing research. Several warfarin pharmacogenetic dosing algorithms and United States Food and Drug Administration-cleared genotyping tests are available for clinical use. Clinical trials are ongoing to determine the clinical utility and cost-effectiveness of genotypeguided warfarin dosing. Results from these trials will likely influence clinical uptake and third party payer reimbursement for genotype-guided warfarin therapy. There is still a lack of pharmacogenetic data for the newly approved oral anticoagulants, dabigatran and rivaroxaban, and with other oral anticoagulants in the research and development pipeline. These data, once known, could be of great importance as routine monitoring parameters for these agents are not available.     

中国人群CYP4F2基因多态性对华法林抗凝作用的影响

目的:研究中国人群中CYP4F2基因多态性对华法林抗凝作用的影响。方法:本研究纳入我院应用华法林进行抗凝治疗的患者,对患者CYP4F2基因多态性位点用连接酶检测反应进行检测,以国际标准化比值(INR)作为监测指标,统计学分析基因位点的多态性与华法林用药剂量个体间差异的相关性。结果:207例样品中,CYP4F2基因突变率为22.2%,其中杂合子分型为35.7%,且达到遗传平衡。不同基因分型组间的华法林剂量未见显著性差异,但是携带T的患者华法林稳定剂量有逐步升高的趋势。结论:CYP4F2基因多态性对华法林稳定期剂量有影响但不显著。     

Phenylbutazone-warfarin interaction in the dog.

The administration of phenylbutazone together with warfarin to dogs resulted in an elevation of the free fraction of warfarin in the plasma from 2-6 to 8-0% thus providing direct support for the notion that phenylbutazone induced inhibition of warfarin binding to plasma proteins. This inhibition as evaluated by a kinetic method was accompanied by a two-fold decrease in the plasma half-life of warfarin from 18-4 h in control animals to 9-6 h in phenylbutazone-treated animals. Marked increases in warfarin-induced hypoprothrombinaemia were observed when at doses up to 8 mg kg-1 (orally) it was given with phenylbutazone (50 mg kg-1, orally). The unbound fraction of warfarin in canine plasma ranged from 1-7 to 4-3% indicating individual differences in the extent of the plasma binding of warfarin in the dog.