MDR1基因多态性对肾移植受者个体化应用他克莫司及预后的影响

目的 研究肾移植受者的多药耐药基因1(MDR1) C3435T和G2677T/A单核苷酸多态性(SNP)对他克莫司(Tac)个体化应用及受者预后的影响.方法 对127例移植肾功能稳定的肾移植受者进行随访,采用引物特异性聚合酶链反应技术分析其MDR1基因C3435T和G2677T/A的SNP,并监测受者全血Tac浓度谷值.结果 91例(71.65％)接受常规Tac三联免疫抑制治疗(非辅助治疗者),另36例受者(28.35％)需要辅助药物提高Tac浓度(辅助治疗者).3435C基因型者在辅助治疗者中占68.05％,在非辅助治疗者中占48.35％ (P＜0.01).非辅助治疗者中,MDR1G2677T/A、C3435T各基因型的血Tac浓度/剂量[单位为(μg/L)/(mg/kg)]的差异均无统计学意义(P＞0.05),C3435T-G2677T/A的单倍体分析也为相同结果(P＞0.05).4年随访期间,13例移植肾功能丧失,其中84.6％(11/13)的受者有MDR1 3435C基因位点,与移植肾功能正常者相比较,此基因型频率的差异无统计学意义(P＞0.05).结论 对于需要用辅助治疗升高Tac浓度的肾移植受者,其3435C基因型出现的几率高,C基因型受者可能倾向于发生移植肾功能丧失.     

肾移植受者CYP3A5基因多态性对术后他克莫司药物代谢的影响

目的 研究肾移植受者细胞色素P450 3A(CMP3A)酶系中的CYP3A5基因多态性对术后他克莫司(Tac)药物代谢的影响,并探讨测定CYP3A5基因型的方法 .方法 选取97例肾移植术后常规使用Tac+吗替麦考酚酯+泼尼松三联免疫抑制方案的受者.用焦磷酸测序法测定受者CYP3A5基因型;用均相酶扩大免疫分析法(EMIT)测定受者全血Tac浓度谷值(C0);比较不同基因型的受者肾移植术后第7天、第14天、1个月、3个月和6个月时的Tac C0,与Tac校正剂量的比值(Tac G0/Tac校正剂量).结果 焦磷酸测序法能够快速准确的测定肾移植受者CYP3A5基因型;97例肾移植受者CYP3A5基因型分别为:CYP3A5+1/*1型17例(17.5%),CYP3A5* 1/*3型35例(36.1%),CYP3A5*3/*3型45例(46.4%).CYP3A5*1/*1型和CYP3A5*1/*3型受者肾移植术后Tac G0/Tac校正剂量均显著低于CYP3A5*3/*3型受者.结论 肾移植受者CYP3A5基因型对Tac药物代谢具有显著的影响.采用焦磷酸法测定肾移植受者CYP3A5基因多态性,有助于确定不同个体移植术后理想的Tac起始剂量,实现Tac个体化用药.     

肾移植术后稳定期受者应用他克莫司的剂量及血药浓度个体差异的研究

他克莫司(Tac)的应用使肾移植受者临床疗效发牛了根本改善,但其较窄的治疗指数和不同个体间的高度差异一直困扰着临床医师.我们从药物基因组学角度分析了肾移植受者细胞色素酶P450-3A5(CYP3A5)和多药耐药基因((MI)R1)的基因多态性,并紧密结合肾移植术后稳定期受者的临床特点,采用多元线性同归分析方法对119例受者进行了研究,以探讨肾移植术后稳定期受者Tac应用剂量及血药浓度个体差异的原因.     

西罗莫司在肝移植术后免疫抑制中的效果及安全性

目的 探讨肝移植术后应用西罗莫司(SRL)的免疫抑制效果和安全性.方法 对21例以SRL作为免疫抑制维持治疗的肝移植受者进行了观察.其中术后直接应用SRL者6例(术前肾功能不全者2例、原发病为肿瘤者4例);因他克莫司(Tac)药物相关性因素替换为SRL者15例(Tac肾毒性4例、高度可疑Tae肝毒性8例、Tac用量过大仍不能达到预期血药浓度者3例).术后对21例受者平均随访25.4个月(6～42个月),评估SRL的临床免疫抑制效果及安全性.结果 随访期间,2例受者因药物副反应停药,药物耐受率为90.5%.发生急性排斥反应1例次,经治疗后痊愈,其余患者均获得良好的免疫抑制效果.Tac肾毒性患者肾功能改善3例;Tac肝毒性患者肝功能显著好转6例.结论 SRL作为受者肝移植术后的免疫抑制维持治疗是安全有效的.术后早期及时用SRL替换Tac可有效逆转后者所致的肝、肾毒性损害.     

汉族肾移植受者稳定期CYP3A5*3基因多态性与血西罗莫司浓度的相关性

目的 探讨中国汉族稳定期肾移植受者CYP3A5*3和MDR1C3435T基因多态性与血西罗莫司浓度的相关性及个体间差异的影响因素.方法 以112例中国汉族稳定期肾移植受者为研究对象,记录受者性别、年龄、身高、体质量等,采用直接测序法检测CYP3A5*3和MDR1C3435T基因型,化学发光微粒子免疫检测法测定全血西罗莫司浓度谷值(C0).研究血西罗莫司浓度个体间差异的影响因素,比较CYP3A5*3和MDR1C3435T不同基因型受者间血西罗莫司浓度的差异.结果 112例中,CYP3A5*1/*1型10例,*1/*3型49例,*3/*3型53例,*1、*3等位基因的出现频率分别为30.81％和69.19％.MDR13435CC型31例,CT型60例,TT型21例,C、T等位基因的出现频率分别为54.46％和45.54％.受者CYP3A5*3基因型是血西罗莫司浓度的主要影响因素(P=0.000),性别、年龄、身高、术后时间、血肌酐、血红蛋白、联合应用环孢素A和MDR1C3435T基因型对血西罗莫司浓度均无影响(P＞0.05).*1/*1型受者C0·剂量-1·体质量-1为(0.0721±0.0202)μg·L-1·mg-1·kg-,*1/*3型受者为(0.1055±0.0395)μg· L-1 ·mg-1 ·kg-1,*3/*3型受者为(0.1395±0.0537)μg·L-1·mg-1 ·kg-1(P＜0.01).不同基因型受者C0·剂量-1·体质量-1的关系为*3/*3型＞*1/*3型＞*1/*1型,*1/*3型受者是*1/*1型的1.46倍,*3/*3型受者是*1/*1型的1.93倍.结论 汉族稳定期肾移植受者的CYP3A5*3基因多态性是其血西罗莫司浓度的主要影响因素,MDR1C3435T基因多态性则对其无影响.与CYP3A5* 3/*3型受者相比较,CYP3A5* 1/*1、*1/*3型受者为达到目标血药浓度需服用更高剂量的西罗莫司.     

肾移植受者新发高甘油三酯血症的危险因素：单中心分析

目的 探讨肾移植受者新发高甘油三酯血症（HTG）的危险因素。方法 回顾性分析149例肾移植受者的临床资料,根据术后血清甘油三酯（TG）水平,分为无HTG组（TG≤1.7 mmol/L,60例）与新发HTG组（TG>1.7 mmol/L,89例）。比较两组受者的一般资料,采用广义估计方程（GEE）分析肾移植受者发生HTG的危险因素,并应用多个回归方程验证。结果 两组受者一般资料差异均无统计学意义（均为P>0.05）。多因素分析结果显示,与低浓度Tac组受者相比,中浓度Tac组和高浓度Tac组的HTG发生率升高[中浓度Tac组比值比（OR） 3.11, 95%可信区间（CI） 1.22～7.93, P=0.018;高浓度Tac组OR5.11, 95%CI1.31～19.98,P=0.019]。与A型血受者相比,O型血受者新发HTG的风险增加（OR 2.77,95%CI 1.14～6.71,P=0.024）。随着术前球蛋白水平升高,受者新发HTG的风险降低（OR 0.93,95%CI 0.87～0.99,P=0.043）。术后3个月时,新发HTG组Tac血药浓度高于无HTG组,差...     

肾移植受者术后早期他克莫司用药剂量及浓度个体差异的研究

目的 探讨肾移植受者术后早期他克莫司(FK506)剂量及浓度个体差异的原因.方法 肾移植术后早期采用FK506、霉酚酸酯及激素三联免疫抑制剂的受者118例,记录性别、年龄、身高,术后第3、7、14、30天分别记录体质量、FK506剂量,激素剂量、腹泻、血脂、肝功、肾功、白蛋白、血细胞比容等指标,测定每例患者细胞色素酶P450-3A5(CYP3A5)和多药耐药基因1(MDRl)3435、2677、1236位点基因多态性及不同时期FK506全血谷浓度,以FK506浓度/(剂量X体表面积)为因变量分别进行多元线性回归分析.结果 多元线性回归模型的拟合度偏低,修正R2值在术后第3、7、14、30天分别为0.284、0.267、0.417、0.324.药物基因组学因素有MDR1 2677、MDRl 1236、MDR1 3435且变化剧烈,不同个体达到相同FK506浓度所需剂量突变型纯合子＜杂合子＜野生型纯合子.非药物基因组学因素在术后第3天为年龄、白蛋白和高密度脂蛋白胆固醇,第7天为白蛋白、年龄和血清肌酐,第14天为激素剂量和天冬氨酸转氨酶,上述影响因素均与FK506浓度/(剂量×体表面积)呈正相关.结论 肾移植术后早期受者FK506剂量及浓度个体差异的原因主要是术后用药和受者剧烈的内环境变化,并与受者MDR1基因多态性、年龄、白蛋白、移植肾功能恢复情况、血脂和肝功能有关,术前应充分透析,尽可能改善患者一般情况,术后应当尽量避免使用对FK506吸收和代谢干扰大的药物.     

MDR基因多态性对肾移植受者环孢素A急性肾毒性发生率的影响

目的 探讨供、受者细胞膜P-糖蛋白(P-gp)的编码基因(MDR基因)多态性对肾移植受者环孢素A(CsA)急性肾毒性发生率的影响.方法 采用聚合酶链反应/限制性片段长度多态性(PCR/RFLP)方法分析173例肾移植供、受者MDR基因外显子26(exon26)基因型;分别以供者和受者exon26基因型进行分组,观测术后3个月内受者血尿素氮、血肌酐和24 h尿量等指标与供、受者exon26基因型之间的关系.结果 供者和受者exon26基因型均为CC、CT和TT三种类型.173例供者中,CC、CT和TTr型比例分别为:28.3%(49/173)、41.6%(72/173)和30.0%(52/173);173例受者中,CC、CT和TT基因型比例分别为:27.7%(48/173)、40.5%(70/173)和31.8%(55/173).供、受者间exon26基因型的类型和分布比例相似,差异无统计学意义(P>0.05).肾移植术后,共有48例受者符合CsA急性肾毒性诊断标准.按受者CC、CT、TT型分组时,各组受者CsA急性肾毒性的发生率分别为25.0%(12/48)、41.7%(20/48)和33.3%(16/48),各组间比较,差异无统计学意义(P>0.05);按供者CC、CT和TT基因型分组时,各组受者术后CsA急性肾毒性的发生率分别为14.6%(7/48)、50.0%(24/48)和35.4%(17/48),CC与CT和TT型之间比较,差异有统计学意义(P<0.05).而且.受者CC型组肾功能异常发生率明显高于供者CC型组(P<0.05).结论 MDR基因多态性对肾移植受者CsA急性肾毒性发生率具有明显的影响,而发挥作用是供者MDR基因多态性.     

CYP3A5基因多态性对中国肾移植受者他克莫司血药浓度和疗效的影响

目的研究CYP3A5基因多态性对肾移植受者他克莫司（FK506）血药浓度／剂量比（blood drag concentration／dose,C／D）,术后急性排斥反应（AR）及不良反应发生率的影响。方法采用聚合酶链反应-限制性片段长度多态性技术检测’肾移植受者CYP3A5基因型,并以直接测序法进行验证。比较不同基因型患者之间的FK506C／D值,AR、不良反应的发生率。结果肾移植术后3个月内,＊3／＊3基因型患者FK506的C／D值为149±59,明显高于＊1／＊1基因型和＊1／＊3基因型患者的78±24和90±42（均为P〈0．05）;移植术后3个月内＊1／＊1基因型患者的AR发生率与＊1／＊3基因型和＊3／＊3基因型患者的AR发生率比较差异无统计学意义。＊1／＊1基因型和＊1／＊3基因型患者比较,＊3／＊3基因型患者术后肝功能异常、药物肾毒性不良反应的发生率较高（均为P〈0．05）。结论CYP3A5基因多态性对服用FK506肾移植患者的C／D值、肝功能异常、药物肾毒性有一定影响。CYP3A5＊3／＊3基因型患者的FK506的C／D值、肝功能异常和药物肾毒性不良反应的发生率较高。     

DCD供者CYP3A5基因型对肝移植受者术后他克莫司个体化用药的指导意义

目的 研究心脏死亡器官捐赠(DCD)供者的CYP3A5基因型对肝移植受者术后早期Tac起始用量的指导意义,为Tac的使用提供个体化方案.方法 选择2010年3月至2013年3月接受DCD供肝移植,且与供者CYP3A5基因型不相同的受者36例,将受者分为实验组和对照组.两组受者术后均采用Tac+吗替麦考酚酯+泼尼松的三联免疫抑制方案,实验组受者根据供者CYP3A5基因型的不同调整Tac的起始用量,对照组受者按照传统方法经验给药.两组受者吗替麦考酚酯和泼尼松的使用无差别.结果 术后7d,实验组受者的血Tac浓度为(7.47±1.83)μg/L,达目标血Tac浓度的受者占72.2％(13/18),对照组为(8.68±5.14)μg/L,达目标血Tac浓度的受者占38.9％(7/18),两组比较,差异有统计学意义(P＜0.05).实验组需要调整Tac剂量的受者占22.2％,而对照组受者占55.6％,两组比较,差异有统计学意义(P＜0.05).术后3个月内,实验组与对照组急性排斥反应发生率分别为22.2％(4/18)和27.8％(5/18),Tac不良反应发生率分别为11.1％(2/18)和22.2％(4/18),实验组均低于对照组,但差异均无统计学意义(P＞0.05).结论 根据DCD供者CYP3A5基因型的不同,可以科学调整Tac的初始剂量,使肝移植受者术后尽早达到目标血Tac浓度,减少排斥反应发生率和降低Tac不良反应,实现Tac的个体化用药.     

Influence of CYP3A5 and MDR1 (ABCB1) polymorphisms on the pharmacokinetics of tacrolimus in renal transplant recipients

BACKGROUND: A body-weight-based dose of tacrolimus often results in marked individual diversity of blood drug concentration. Tacrolimus is a substrate for cytochrome P450 (CYP) 3A5 and p-glycoprotein encoded by CYP3A5 and MDR1 (ABCB1), respectively, having multiple single nucleotide polymorphisms. In this study, we genotyped CYP3A5 A6986G, MDR1 G2677(A/T), and C3435T polymorphisms and investigated the association between these polymorphisms and the pharmacokinetics of tacrolimus in renal transplant recipients. METHODS: Thirty consecutive recipients were enrolled in this study. The pharmacokinetics of tacrolimus was analyzed on day 28 after transplant, when the daily dose was adjusted to the target trough level of 10-15 ng/mL. The polymerase chain reaction-restriction fragment length polymorphism and direct sequence method were used for genotyping the CYP3A5 and MDR1 polymorphisms, respectively. RESULTS: The single tacrolimus dose per body weight was significantly higher in CYP3A5 *1 carriers than CYP3A5 *3/*3 carriers (0.143+/-0.050 vs. 0.078+/-0.031 mg/kg, P<0.001). The dose-adjusted trough level and the area under the concentration-time curve (AUC0-12) were significantly lower in CYP3A5 *1 carriers than CYP3A5 *3/*3 carriers (0.040+/-0.014 vs. 0.057+/-0.024 ng/mL/mg/kg, P=0.015 and 0.583+/-0.162 vs. 0.899+/-0.319 ng.hr/mL/mg/kg, P=0.004), respectively. The MDR1 polymorphism was not associated with any pharmacokinetic parameters. CONCLUSIONS: Kidney transplant recipients with the CYP3A5 *1 allele required a higher daily tacrolimus dose compared with those with the CYP3A5 *3/*3 genotype to maintain both the target trough level and AUC0-12, suggesting that this polymorphism is useful for determining the appropriate dose of tacrolimus.     

Impact of CYP3A5 and MDR1(ABCB1) C3435T polymorphisms on the pharmacokinetics of tacrolimus in renal transplant recipients

OBJECTIVE: The objective of this study was to assess the influence of CYP3A5 and MDR1 genetic polymorphisms on tacrolimus pharmacokinetics in Japanese renal transplant recipients. METHOD: The pharmacokinetic parameters of tacrolimus were calculated in steady-state on day 28 after transplantation. Polymerase chain reaction-restriction fragment length polymorphism and direct sequence methods were used for CYP3A5 and MDR1 polymorphisms, respectively. RESULTS: The dose-adjusted area under the concentration-time curve (AUC0-12) was significantly lower among CYP3A5*1 carriers than those bearing CYP3A5*3/*3. (0.570 +/- 0.105 vs 0.865 +/- 0.343 ng.h/mL per mg/kg, P = .00322). The daily tacrolimus dose per body weight was significantly higher in CYP3A5*1 carriers than those of CYP3A5*3/*3 carriers (0.271 +/- 0.110 vs 0.150 +/- 0.056 mg/kg, P = .00016). In this study, a distinction was made between carriers of CYP3A5*1/*1+*1/*3 and CYP3A5*3/*3 to investigate the influence of the MDR1 C3435T mutation on tacrolimus pharmacokinetics. The MDR1 C3435T polymorphisms did not affect any tacrolimus pharmacokinetic parameter in either group. CONCLUSIONS: Renal transplant recipients who were CYP3A5*1 carriers required a higher dose of tacrolimus than CYP3A5*3/*3, indicating a significantly lower dose-adjusted AUC0-12 of tacrolimus. In contrast, MDR1 C3435T polymorphism was not an important factor in tacrolimus pharmacokinetics.     

ABCB1 genotype of the donor but not of the recipient is a major risk factor for cyclosporine-related nephrotoxicity after renal transplantation

Cyclosporine (CsA) nephrotoxicity is a severe complication in organ transplantation because it leads to impaired renal function and chronic allograft nephropathy, which is a major predictor of graft loss. Animal models and in vivo studies indicate that the transmembrane efflux pump P-glycoprotein contributes substantially to CsA nephrotoxicity. It was hypothesized that the TT genotype at the ABCB1 3435C-->T polymorphism, which is associated with decreased expression of P-glycoprotein in renal tissue, is a risk factor for developing CsA nephrotoxicity. In a case-control study, 18 of 97 patients developed CsA nephrotoxicity and showed complete recovery of renal function in all cases when switched to a calcineurin inhibitor-free regimen. Both recipients and donors were genotyped for ABCB1 polymorphisms at the positions 3435C-->T and 2677G-->T/A. For controlling for population stratification, two additional polymorphisms, CYP2D6*4 and CYP3A5*3, with intermediate allelic frequencies were studied. The P-glycoprotein low expressor genotype 3435TT only of renal organ donors but not of the recipients was overrepresented in patients with CsA nephrotoxicity as compared with patients without toxicity (chi2 = 10.5; P = 0.005). CsA dosage, trough levels, and the concentration per dose ratio were not different between the patient groups. In a multivariate model that included several other nongenetic covariates, only the donor's ABCB1 3435TT genotype was strongly associated with CsA nephrotoxicity (odds ratio, 13.4; 95% confidence interval, 1.2 to 148; P = 0.034). A dominant role of the donor's ABCB1 genotype was identified for development of CsA nephrotoxicity. This suggests that P-glycoprotein is an important factor in CsA nephrotoxicity.     

Influence of CYP3A5 and MDR1(ABCB1) polymorphisms on the pharmacokinetics of tacrolimus in Chinese renal transplant recipients

The aims of this study were to investigate the influence of CYP3A5 and MDR1 genetic polymorphisms on tacrolimus pharmacokinetics in Chinese renal transplant recipients, so as to help rational administration in clinical practice. We calculated pharmacokinetic parameters of tacrolimus from blood concentrations in steady state at day 28. Polymerase chain reaction restriction fragment length polymorphisms were used for CYP3A5 and MDR1 analysis. The results showed that the dose-adjusted area under the concentration time curve (AUC_0-12) and renal clearance showed a significant difference between CYP3A5*1 carriers and the CYP3A5*3/*3 genotype (P < .01). In the following study, a distinction was made between carriers of CYP3A5*1/ vs CYP3A5*3/*3 seeking to investigate the influence of the MDR13435T>C polymorphism on tacrolimus pharmacokinetics. MDR1 3435T>C polymorphism did not affect any tacrolimus pharmacokinetic parameter in either group. Renal transplant recipients who were CYP3A5*1 carriers required a higher dose of tacrolimus than CYP3A5*3/*3, indicating a significantly lower dose-adjusted AUC_0-12 of tacrolimus. In contrast, MDR1 3435T>C polymorphism was not an important factor in tacrolimus pharmacokinetics. Pharmacogenetic methods may be used prospectively to aid dose selection and individualize immunosuppressive therapy.     

Impact of genetic polymorphisms on tacrolimus pharmacokinetics and the clinical outcome of renal transplantation

We retrospectively examined the association of polymorphisms in the CYP3A, CYP2J2, CYP2C8, and ABCB1 genes with pharmacokinetic (PKs) and pharmacodynamic (PDs) parameters of tacrolimus in 103 renal transplant recipients for a period of 1 year. CYP3A5 expressers had lower predose concentrations (C(0) )/dose and higher dose requirements than nonexpressers throughout the study. Among CYP3A5*1 carriers, those also carrying the CYP3A4*1B allele showed the lowest C(0) /dose, as compared with CYP3A4*1/CYP3A5*3 carriers (54.28±26.45, 59.12±24.00, 62.43±41.12, and 57.01±17.34 vs. 112.37± 76.60, 123.21±59.57, 163.34±76.23, and 183.07±107.82 at 1 week, 1 month, 5 months, and 1 year after transplantation). In addition, CYP3A4*1B/CYP3A5*1 carriers showed significantly lower dose-corrected exposure than CYP3A4*1/CYP3A5*1 carriers 1 year after transplantation (57.01±17.34 vs. 100.09±24.78; P=0.016). Only the ABCB1 TGC (3435-2677-1236) haplotype showed a consistent association with PDs (nephrotoxicity; OR=4.73; CI: 1.3-16.7; P=0.02). Our findings indicate that the CYP3A4*1B-CYP3A5*1 haplotype may have a more profound impact in tacrolimus PKs than the CYP3A5*1 allele. This study does not support a critical role of the CYP450 or ABCB1 single nucleotide polymorphisms in the occurrence of toxicity or acute rejection in renal transplant recipients treated with tacrolimus.     

Resource utilization among kidney transplant recipients

BACKGROUND: Hospitalization consumes a significant portion of the end-stage renal disease (ESRD) program, which includes kidney transplant recipients. Identification of kidney transplant recipients at risk of increased resource utilization could lead to appropriate interventions to attenuate the complications related to kidney transplant, which may reduce resource utilization. METHODS: This retrospective cohort study of kidney transplant recipients was performed to identify risk factors for hospital utilization. The study population consisted of patients who received kidney transplant at our center between October 1990 and September 1999 and were followed in the outpatient clinic. RESULTS: Of the 220 patients, 171 (78%) were hospitalized during a median follow-up of 36 months. The number of hospitalizations, hospital days, and outpatient visits per patient-year at risk were 1.1, 6.3, and 21.6, respectively. Infection episodes were the leading cause of hospitalization. In a multivariate regression analysis, cytomegalovirus (CMV)-positive status of donor (RR 1.58; 95% CI 1.15, 2.18) and a higher number of hospital days during the transplant hospitalization (RR 1.10 per 7 days increase; 95% CI 1.03, 1.19) were associated with a higher risk of hospitalization, while higher serum albumin (RR 0.84 per 0.5 g/dL increase; 95% CI 0.73, 0.97), higher hematocrit (RR 0.95 per 1% increase; 95% CI 0.92, 0.98), higher glomerular filtration rate (GFR) (RR 0.91 per 10 mL/min/1.73 m2; 95% CI 0.85, 0.99), and an increased interval since transplant (RR 0.84 per 6 months increase; 95% CI 0.75, 0.93) were associated with a lower risk of hospitalization. CMV-positive status of the donor (RR 1.11; 95% CI 1.00, 1.21) and presence of cardiovascular disease (RR 1.12; 95% CI 1.00, 1.24) were associated with a higher risk of outpatient visits, while Caucasian race (RR 0.82; 95% CI 0.73, 0.94), higher serum albumin (RR 0.88 per 0.5 g/dL increase; 95% CI 0.84, 0.93), higher hematocrit (RR 0.96 per 1% increase; 95% CI 0.95, 0.97), and an increased interval since transplant (RR 0.79 per 6 months increase; 95% CI 0.76, 0.83) were associated with a lower risk of outpatient visits. CONCLUSION: Identification of risk factors associated with increase resource utilization among kidney transplant recipients could aid in the development of targeted interventions to improve clinical and economic outcomes.     

霉酚酸酯药代动力学与多重耐药基因1多态性的相关性研究

目的 研究肾移植受者术后早期霉酚酸酯(MMF)的药代动力学与人类多重耐药基因1(MDRI)多态性的相关性.方法 选择初次肾移植的汉族受者28例,肾移植术后2周时,于口服MMF之前及服药后0.5、1、1.5、2、4、6、8、10、12 h共10个时间点分别采集外周血,以高效液相色谱(HPLC)法测定全血霉酚酸酯(MMF)的活性成分霉酚酸(MPA)的浓度,直接观察其峰值浓度(Cmax)和达峰时间(Tmax).应用Winnolin 3.1软件计算MPA 0～12 h药物时间一浓度曲线下面积(AUC)和平均滞留时间(MRT).同时从外周血提取基因组DNA,应用多聚酶链反应-限制性片断长度多态性(PCR-RFLP)测定MDR1第12、21、26号外显子C1236 T、G2677 T/A、C3435 T单核苷酸多态性(SNP).比较3个SNP位点的不同基因型、单倍型间MMF药代动力学参数的差异;比较MPA高暴露组(MPA AUC≥60 mg·h-1·L-1)与MPA低暴露组(MPA AUC＜60 mg·h-1·L-1)间MDR1多态性差异.结果 MDR1第12、21、26号外显子SNP位点突变型纯合子基因型(1236 TT、2677 TT/AA、3435 TT)频率分别为0.368、0.184和0.211.1236 TT基因型受者MPA AUC水平显著高于1236 cc/CT受者,分别为(65.36±11.51)mg·h-1·L-1和(53.33±13.77)mg·h-1·L-1(P=0.032).MPA高暴露组第12号外显子SNP位点上,TT基因型频率显著高于低暴露组,分别为66.7%和15.8%(P=0.013,OR=2.526);T等位基因频率有高于低暴露组的趋势,分别为83.3%和53.3%(P=0.072).结论 具有MDR1第12号外显子TT等位基因的受者,肾移植早期MPA AUC显著高于同一位点其他基因型受者,是MPA高暴露的危险个体.     

Reduced Variability of Tacrolimus Trough Level in Once-Daily Tacrolimus-Based Taiwanese Kidney Transplant Recipients With High-Expressive Genotype of Cytochrome P450 3A5

Background

Our previous study results indicated that conversion from twice-daily Prograf to once-daily Advagraf associated with lower variability of tacrolimus blood trough level. Some factors, such as frequency of interaction by food exposure, expression of cytochrome P450 3A5 genetic polymorphism, and other interactions of unknown factors, could be the reasons for the change of variability. We aimed to clarify the impact of cytochrome P450 3A5 genetic polymorphism on the variability of tacrolimus blood trough level in Taiwanese kidney transplant recipients.

Methods

We collected blood samples from kidney transplant recipients to prepare DNA and then performed single-nucleotide polymorphism genotyping by using the restriction fragment length polymorphism.

Results

We found that 79 (52.7%) of 150 kidney transplant recipients had the low-expressive genotype (CYP3A5*3/*3), whereas the other 71 (47.3%) kidney transplant recipients had high-expressive genotype (CYP3A5*1/*1 and CYP3A5*1/*3). The prevalence of high-expressive genotype is higher than previous reports from western countries. Compared with the patients with high-expressive genotype, the average dose-normalized trough level of tacrolimus was significantly higher in patients with low-expressive genotype. Interestingly, when patients converted from twice-daily Prograf to once-daily Advagraf, the percent coefficient of variation of tacrolimus trough level was significantly decreased in patients with high-expressive genotype.

Conclusion

This study suggested that there is a potential benefit for kidney transplant recipients with cytochrome P450 3A5 high-expressive genotype (*1/*1 or *1/*3) to convert from Prograf to once-daily Advagraf.