MDR1基因C3435T多态性对替米沙坦血药浓度与药动学的影响

目的：探讨健康志愿者和高血压患者的多药耐药基因26（exon26）C3435T基因多态性对替米沙坦的血药浓度和药动学的影响。方法：采用聚合酶链反应（PCR）和限制性内切片段多态性（RFLP）的方法对19例健康志愿者和66例高血压患者进行MDR1基因分型。使用HPLC-MS法测定健康志愿者单剂量口服40mg替米沙坦48h内血药浓度和高血压患者的稳态血药浓度。比较不同基因型之间替米沙坦在健康志愿者的药物动力学的差异,和高血压患者的稳态血药浓度差异。结果：C3435T发生率在健康人群和高血压患者之间没有明显的差异,C3435T的3个不同基因型健康志愿者的Cmax,tmax,AUC0-48,AUC0-∞,CL差异无统计学意义（P〉0．05）。3个基因型的高血压患者的稳态血药浓度差异无统计学意义（P〉0．05）。结论：MDR1C3435T基因多态性对替米沙坦的血药浓度和药动学无影响。     

MDR1 C3435T多态性对关节置换术后镇痛药物使用量的影响

目的:探讨多药耐药基因1(MDR1)C3435T多态性对关节置换术后镇痛药物(地佐辛联合舒芬太尼)使用量的影响。方法:选取2014年1月-2016年2月在天津市人民医院和天津港口医院行关节置换术的患者300例,术后给予地佐辛+舒芬太尼联合镇痛。采用聚合酶链反应-限制性片段长度多态性分析法测定其MDR1 C3435T多态性,比较不同基因型患者术后视觉模拟量表(VAS)评分、镇静程度(Ramesy)评分、地佐辛+舒芬太尼的使用量,以及不良反应发生情况。结果:300例患者中,MDR1C3435T CC、CT和TT基因型分别有100例(33.3%)、102例(34.0%)和98例(32.7%),各基因型频率均符合Hardy-Weinberg平衡(P>0.05)。各基因型患者术后0、24、48 h VAS评分、Ramesy评分比较,差异均无统计学意义(P>0.05),且未见镇静过度者。CT、TT基因型患者术后0~24、>24~48 h地佐辛+舒芬太尼的使用量均显著低于CC基因型患者,差异均有统计学意义(P<0.05);而CT与TT基因型上述各时间段药物使用量比较,差异均无统计学意义(P>0.05)。TT基因型患者术后恶心呕吐(PONV)及总体不良反应发生率均显著低于CC、CT基因型患者,差异均有统计学意义(P<0.05);而CC与CT基因型患者PONV及总体不良反应发生率,以及各基因型患者瘙痒的发生率比较,差异均无统计学意义(P>0.05)。结论:在达到相似镇痛、镇静效果的前提下,MDR1C3435T突变型患者对地佐辛+舒芬太尼的耐受性更低,所需剂量更少,且不良反应发生率更低。该基因型可作为临床个体化治疗的参考指标。     

Human MDR1 polymorphism: G2677T/A and C3435T have no effect on MDR1 transport activities

The two most frequently observed single nucleotide polymorphisms (SNPs) of the human multidrug resistance 1 (MDR1) gene are 2677G/T/A (893Ala/Ser/Thr) and 3435C/T (no amino acid substitution). In this study, six forms of MDR1 cDNAs with the SNPs were expressed in LLC-PK1 cells and their transport activities were determined. Nearly identical amounts of the recombinant MDR1 proteins were expressed in the established cell lines using the Flp recombinase, which integrates a gene of interest at a specific genomic location. Four structurally diverse compounds: verapamil, digoxin, vinblastine and cyclosporin A, were examined for transcellular transport activities and intracellular accumulation. No significant differences were observed between cells expressing five polymorphic types of the MDR1 cDNAs (2677G/3435T, 2677A/3435C, 2677A/3435T, 2677T/3435C, 2677T/3435T) and cells expressing the wild-type (2677G/3435C). These results suggested that the two frequently observed MDR1 SNPs had no effect on the transport activities of MDR1 proteins expressed in LLC-PK1 cells in vitro, and other genetic or environmental factors might control the expression of MDR1 and the in vivo activity of MDR1.     

Allele and genotype frequency of MDR1 C3435T in Tamilian population

The allele and genotype frequencies of MDR1 C3435T polymorphism were determined in 185 unrelated healthy Tamilians. The genomic DNA was extracted from peripheral leucocytes using phenol chloroform method and genotyped by PCR-RFLP method. The frequencies of MDR1 C3435 and T3435 alleles in Tamilian population were 0.46 and 0.54 respectively. The distribution of T3435 in this population was found to be greater than Africans and almost similar to Caucasians and Orientals. The distribution of CC, CT and TT genotypes was 0.18, 0.56 and 0.26 respectively. The frequency distribution of the CC genotype was lower in them when compared with Chinese and Africans whereas CT genotype was higher in comparison with all the major ethnic groups.     

Meta-analysis of the influence of MDR1 C3435T polymorphism on digoxin pharmacokinetics and MDR1 gene expression

AIMS: Studies revealing conflicting results of the functional significance of MDR1 exon 26 C3435T SNP on the disposition of digoxin in different ethnic groups led us to perform a meta-analysis on published data investigating the influence of C3435T SNP on the pharmacokinetics of digoxin and the expression of MDR1. METHODS: Meta-analysis was performed on data from published studies investigating the influence of MDR1 C3435T SNP on digoxin pharmacokinetics, as well as MDR1 expression in Caucasian and Japanese populations. The following outcomes were included: exposures to digoxin measured by area under the concentration-time curve and maximum concentration, the mean intestinal MDR1 mRNA expression and P-gp expression in the absence of digoxin administration. RESULTS: The overall results of the meta-analysis in Caucasian and Japanese subjects suggested no major influence of the C3435T SNP on exposure levels of digoxin as determined by AUC(0-4 h) or AUC(0-24 h) although C(max) values for digoxin were lower in wild-type (CC) subjects compared with subjects harbouring TT genotypes. Subgroup analysis by ethnic populations showed the oral availability of digoxin to be lower in wild-type Caucasian populations compared with wild-type Japanese subjects. No causal relationships were detected between the C3435T SNP and MDR1 mRNA or protein expression. CONCLUSIONS: Our meta-analysis of available studies indicates that the synonymous MDR1 C3435T SNP does not affect the pharmacokinetics of digoxin and the expression of MDR1 mRNA. Future studies should focus on the impact of MDR1 haplotypes on the pharmacokinetics of MDR1 substrates rather than the C3435T SNP alone.     

MDR1C3435T基因多态性与芬太尼术后镇痛效应的关系

目的探索MDR1C3435T基因多态性与芬太尼术后镇痛效应的关系。方法术后随访患者并记录芬太尼镇痛使用量及不良反应发生情况,采用聚合酶链反应一限制性片段长度多态性（eCR-RFLP）技术对129例患者进行基因分型,比较不同基因型间芬太尼镇痛效应的差异。结果129例患者中、CC型51例（39．5％）、CT型57例（44．2％）、111型21例（16．3％）。CT型、TT型患者24h芬太尼镇痛使用量显著低于CC型（P〈0．05）,TT型患者48h芬太尼镇痛使用量显著低于CC型（P〈0．05）,CT型与CC型48h芬太尼镇痛量、不同基因型组间不良反应发生率差异无统计学意义。结论MDR1C3435T与术后不良反应无相关性,但与芬太尼术后镇痛使用量具有相关性,该基因型可能成为疼痛个体化治疗的参考指标。     

MDR1 C3435T基因多态性与胃溃疡患者治疗相关性分析

目的 分析MDR1 C3435T基因多态性与胃溃疡患者治疗的相关性.方法 回顾性分析2010年10月至2015年10月来我院就诊的胃溃疡患者共80名,其中Hp阳性患者47例,另选取80例健康体检者作为对照组,测定两组入选对象MDR1 C3435T基因多态性,比较不同基因型胃溃疡患者治疗后Hp阳性率和耐药率.结果 观察组(Hp阳性)患者3435TT基因型频率和T等位基因频率均明显高于观察组(Hp阴性)和对照组(P＜0.05);观察组(Hp阴性)患者3435TT基因型频率和T等位基因频率亦均明显高于对照组(P＜0.05).治疗后3435TT基因型患者Hp阳性率和耐药率均明显高于C3435T和CC3435基因型患者(P＜0.05).结论 MDR1 C3435T基因多态性与胃溃疡患者的治疗具有相关性,3435TT基因型患者较难根除Hp,耐药性较强.     

MDR1 C3435T基因多态性对环孢素体内代谢影响的荟萃分析

目的 过荟萃分析进一步观察MDR1 3435T 基因多态性对于环孢素体内代谢的影响。方法 过Pubmed搜索C3435T基因多态性对于环孢素体内代谢影响的相关文献，提取AUC0-4，AUC0-12，AUC0-inf,Cmax,CL/F,和C0等药物动力学参数，使用STATA9.1软件进行荟萃分析。结果 共有14篇参考文献，包括1036名受试者符合本次荟萃分析的入选争件，荟萃分析显示在C3435T野生型杂合子（CC）中，AUC0-12低于其他基因型的受试者。在白种人中，C3435T野生型杂合子（CC）携带者的C0低于其他基因型的白种受试者。其他药物动力学参数在C3435T各基因型之间未见显著差异。结论本荟萃分析没有发现MDR1 C3435T基因多态性对于环孢素体内代谢有较大的影响，但是观察指标的选择是观察结果差异的原因之一；MDR1 C3435T表型和基因型的相关性可能存在种族差异．     

Frequency of the C1236T, G2677T/A and C3435T MDR1 gene polymorphisms in the Serbian population

The multi-drug resistance 1 (MDR1) gene encodes for a P-glycoprotein (PGP), which acts as a gate-keeper against various kinds of xenobiotics. Several single nucleotide polymorphisms (SNPs) in the MDR1 gene that may influence PGP level and function have been identified. The aim of this study was to simultaneously analyze the three most important MDR1 SNPs, C3435T, G2677T/A and C1236T, in the Serbian population and to compare the results with those published for other ethnic groups. A group of 158 unrelated, healthy subjects was included in the present study. For determination of MDR1 SNPs, a multiplexed mutagenically separated PCR was performed. The genotype frequency of the analyzed MDR1 SNPs was as follows: 3435 nt - 0.19 (CC), 0.54 (CT) and 0.27 (TT); 2677 nt - 0.26 (GG), 0.52 (GT), 0.15 (TT), 0.03 (GA) and 0.064 (TA), and 1236 nt - 0.23 (CC), 0.61 (CT) and 0.16 (TT). Our results for the Serbian population could be relevant for further investigation of drugs that are substrates of PGPand for studies of interethnic diversity in MDR1 polymorphism frequency.     

Meta-analysis of the effect of MDR1 C3435T polymorphism on cyclosporine pharmacokinetics

The published data revealed conflicting results of the polymorphism of MDR1 exon 26 SNP C3435T on the pharmacokinetics of cyclosporine; thus, the aim was to conduct a meta-analysis of significant magnitude to investigate the influence of SNP C3435T on the pharmacokinetics of cyclosporine. A literature search was conducted to locate the relevant papers by using the PubMed electronic source from 1997 and onwards. The pharmacokinetic parameters, including AUC(0-4), AUC(0-12), AUC(0-inf), C(max), CL/F and trough concentration (C(0)), were extracted and a meta-analysis was performed by using Stata version 9.1. A total of 14 papers concerning 1036 individuals were included in the meta-analysis. The overall results showed no major influence of SNP C3435T on the pharmacokinetic parameters, including AUC(0-4), AUC(0-inf), CL/F, C(max) and C(0), although AUC(0-12) was lower in subjects with CC genotype. A subanalysis by ethnic population showed that C(0) was lower in Caucasian individuals harbouring CC genotype. In conclusion, our meta-analysis of available studies has thus far failed to demonstrate a definitive correlation between the SNP C3435T in MDR1 gene and alterations in P-glycoprotein function that can result in altered pharmacokinetics of cyclosporine, although it was indicated in this meta-analysis that the carrier of CC genotype of the SNP C3435T of MDR1 had lower cyclosporine exposure presented as AUC(0-12) than those with at least one T allele. There seems to be ethnic differences in the relationship between the SNP C3435T of MDR1 and cyclosporine pharmacokinetics.     

丙型肝炎病毒感染的危险因素病例对照研究

目的:应用病例对照研究的方法分析丙型肝炎病毒感染的危险因素。方法:RT-PCR法定性测定HCV RNA,EIA法检测抗HCV。危险因素分析采用病例对照研究方法(病例数:对照数=1:4),用单因素分析筛选出危险因素,再应用多因素logistic回归分析确定危险因素。结果:单因素分析筛选出的危险因素有输血、静脉吸毒、纹身、流产、暴露性伤口缝合术、性伴有肝炎病史者、未用避孕套并性伴数多于1位者、社会经济贫困者、未婚怀孕者、与有丙肝病史的性伴共用生活用品者。多因素logistic回归分析确定的高危因素分别为输血、静脉吸毒、未用避孕套并性伴数多于1位。结论:输血、静脉吸毒、多于1个性伴而不用避孕套的性行为是丙型肝炎病毒感染的直接危险因素。     

Effect of the MDR1 C3435T variant and P-glycoprotein induction on dicloxacillin pharmacokinetics

This study investigated 2 hypotheses about genotype-phenotype relationships for the efflux transporter, P-glycoprotein: (1) the presence of a synonymous C3435T variant in exon 26 of the MDR1 gene correlates to higher plasma concentrations of a P-glycoprotein substrate, dicloxacillin, and (2) the effects of genotypic differences decrease under conditions of P-glycoprotein induction by rifampin. Eighteen healthy volunteers received two 1-g doses of dicloxacillin, one on the 1st study day and the other on the 11th day of rifampin dosing (600 mg daily). Dicloxacillin and its 5-hydroxymethyl metabolite were analyzed using liquid chromatography/tandem mass spectrometry. Mean dicloxacillin C(max) measurements were 30.5 +/- 13.5, 33.3 +/- 4.7, and 31.1 +/- 12.8 mug/mL in individuals with the CC, CT, and TT genotype at position 3435 in exon 26 of the MDR1 gene. Following rifampin dosing, the mean dicloxacillin C(max) across genotypes decreased from 31.4 +/- 10.8 to 22.9 +/- 7.0 microg/mL (P < .05), whereas the mean oral clearance increased from 235 +/- 82 to 297 +/- 71 mL/min (P < .001), and the mean absorption time increased from 0.71 +/- 0.55 to 1.34 +/- 0.77 h (P < .05). Rifampin treatment increased the formation clearance, C(max), and AUC of the 5-hydroxymethyl metabolite by 135%, 119%, and 59%, respectively. The C3435T variant had no effect on dicloxacillin pharmacokinetics. The data suggested that rifampin induced intestinal P-glycoprotein and increased dicloxacillin metabolism.     

MDR1基因C3435T多态性对重症肌无力患者环孢素血药浓度的影响

目的 :研究MDR1基因C3435T多态性与重症肌无力患者环孢素药物动力学的关系。方法 :采用荧光PCR的方法检测 96名重症肌无力 (MG)患者MDR1C3435T基因型 ,其中临床资料较全的 73名 ,对其环孢素用药的血药检测结果与基因型结果分析。结果 :重症肌无力患者MDR1C3435T的分布频率接近 1:1;野生型 3435CC患者的环孢素全血谷浓度高于杂合型和突变型 (P <0 .0 5 ) ,杂合型与突变型之间无明显差异。结论 :药物遗传学研究对环孢素治疗重症肌无力患者的临床合理用药有指导意义。     

Effect of ABCB1 C3435T Polymorphism on Pharmacokinetics of Antipsychotics and Antidepressants

P‐glycoprotein, encoded by ABCB1, is an ATP‐dependent drug efflux pump which exports substances outside the cell. Some studies described connections between C3435T polymorphism T allele and lower P‐glycoprotein expression; therefore, homozygous T/T could show higher plasma levels. Our aim was to evaluate the effect of C3435T on pharmacokinetics of 4 antipsychotics (olanzapine, quetiapine, risperidone and aripiprazole) and 4 antidepressants (trazodone, sertraline, agomelatine and citalopram). The study included 473 healthy volunteers receiving a single oral dose of one of these drugs, genotyped by real‐time PCR. Multivariate analysis was performed to adjust the effect of sex and genotype of the main cytochrome P450 enzymes. C3435T polymorphism had an effect on olanzapine pharmacokinetics, as T/T individuals showed lower clearance and volume of distribution. T/T individuals showed lower T_1/2 of 9‐OH‐risperidone, but this difference disappeared after multivariate correction. T/T homozygous individuals showed lower dehydro‐aripiprazole and trazodone area under the concentration‐time curve, along with lower half‐life and higher clearance of trazodone. C/T genotype was associated to higher citalopram maximum concentration. C3435T had no effect on quetiapine, sertraline or agomelatine pharmacokinetics. C3435T can affect the elimination of some drugs in different ways. Regarding risperidone, trazodone and dehydro‐aripiprazole, we observed enhanced elimination while it was reduced in olanzapine and citalopram. However, in quetiapine, aripiprazole, sertraline and agomelatine, no changes were detected. These results suggest that P‐glycoprotein polymorphisms could affect CNS drugs disposition, but the genetic factor that alters its activity is still unknown. This fact leads to consider the analysis of ABCB1 haplotypes instead of individual variants.     

MDR1 C3435T polymorphism is predictive of later onset of ulcerative colitis in Japanese

Recently, a silent polymorphism of C3435T of the MDR1 gene, encoding the multidrug resistant transporter MDR1/P-glycoprotein, has been found to be associated with susceptibility to ulcerative colitis (UC), but this remains controversial. This study was conducted to find a possible reason for the discrepancies, and it was suggested that the age of onset was important for the association, namely, C3435T was predictive of susceptibility to later onset UC, but not for early onset UC. Linkage disequilibrium of C3435T with T-129C, C1236T and G2677A, T was suggested to be altered in UC, but the analysis of their haplotype provided no advantage in terms of prediction over that with only C3435T. The effect of C3435T on susceptibility could not be explained by that on mRNA expression in rectal mucosa, but it was greater in the C(3435)-noncarriers in the early onset group, allowing the individualization of steroid-based pharmacotherapy.     

Frequency of C3435T single nucleotide MDR1 genetic polymorphism in an Asian population: phenotypic-genotypic correlates

AIMS: To investigate the frequency of the single nucleotide polymorphism C3435T in exon 26 of the MDR1 gene in Asians and to determine the functional significance of this SNP with the clinical pharmacokinetics of oral cyclosporin (Neoral) in 10 stable heart transplant patients. METHODS: The MDR1 C3435T polymorphism was investigated in 290 healthy Asian subjects (98 Chinese, 99 Malays and 93 Indians). We also compared the MDR1 polymorphism between the Asian population studied here and the published data on Africans and Caucasians. The clinical relevance of this SNP on oral bioavailability of a known P-gp substrate, cyclosporin, was assessed in 10 stable Chinese heart transplant patients. RESULTS: The homozygous TT genotype was observed in 32%, 28% and 43% of Chinese, Malays and Indians. The homozygous CC genotype was found in 25% of Chinese and Malays compared with 18% of Indians. The Indians had a lower frequency of the C allele [0.38 (0.31-0.45)] compared with the Chinese [0.46 (0.39-0.53)] and Malays [0.48 (0.42-0.55)]. Chi-squared test showed that the distribution of allele frequencies between the Malays and Indians differed significantly (P = 0.04). In this Asian population, the overall distribution of genotypes (CC, CT and TT) and allele frequencies were significantly different from those in Africans (P < 0.001). The results were also significant when the Chinese, Malays and Indians were compared separately with the African group (P < 0.001). Compared with the Caucasian data, the overall distribution of genotype and allele frequencies in the Asian population were also significantly different (P < or = 0.05). However, when each Asian ethnic group was compared separately with the Caucasians, only the Indians were found to be significantly different (P < or = 0.004). Genotypic-phenotypic correlations of this SNP were assessed in 10 stable Chinese heart transplant patients. The median AUC(0,4 h) was 11% lower in patients with CC genotype compared with subjects with TT genotype. However, the interpatient variability in AUC(0,4 h) was high in patients, especially in those with CC genotype. CONCLUSIONS: The distribution of the SNP C3435T in exon 26 in the Chinese and Malay population was found to be similar to the Caucasians whereas the Indians were different. The Asian population also differed significantly from the African and Caucasian population in the distribution of the C3435T SNP. The low frequency of the T allele in the Indian population implies lower expression of P-gp and may have important therapeutic and prognostic implications for use of P-gp dependent drugs in individuals of Indian origin.     

Detection of MDR1 single nucleotide polymorphisms C3435T and G2677T using real-time polymerase chain reaction: MDR1 single nucleotide polymorphism genotyping assay

The objective of this study was to develop a real-time polymerase chain reaction (PCR) method to detect MDR1 (human multidrug resistance gene) single nucleotide polymorphisms (SNPs) C3435T and G2677T. C3435T and G2677T are linked to MDR1 ^*2, which is associated with enhanced efflux activity in vitro. Using the Smart Cycler, an allele-specific real-time PCR-based genotyping method was developed to detect C3435T and G2677T. The MDR1 genotype of human genomic DNA templates was determined by direct DNA sequencing. PCR reactions for genotyping C3435T and G2677T by using allele-specific primers were conducted in separate tubes. An additional nucleotide mismatch at the third position from the 3′ end of each allele-specific primer was used to abrogate nonspecific PCR amplification. The fluorescence emitted by SYBR Green I was monitored to detect formation of specific PCRproducts. PCR growth curves exceeding the threshold cycle were considered positive. Fluorescence melt-curve analysis was used to corroborate results from PCR growth curves. Using PCR growth curves, our assay accurately determined hetero- and homozygosity for C3435T and G2677T. Genotype assignments based on PCR growth curve, melt-curve analysis, agarose gel electrophoresis, and direct DNA sequencing results of PCR products were in perfect agreement. We have developed a rapid MDR1 genotyping method that can be used to assess the contribution of MDR1 ^*2 to pharmacokinetic and pharmacodynamic variability of P-glycoprotein substrates.     

MDR1 C3435T基因多态性与肾移植患者他克莫司血药浓度关系的Meta分析

目的:系统评价多药耐药基因1(MDR1)C3435T基因多态性与肾移植患者他克莫司(FK506)血药浓度的关系,为器官移植术后免疫抑制剂的精准化治疗提供循证参考。方法:计算机检索数据库Embase、Science Direct、Pubmed、CNKI、Wan fang、Conchrane,Clinicaltrials.gov,检索年限为1990年1月至2016年10月,检索语种为中文和英文,收集有关MDR1C3435T基因多态性与肾移植患者FK506血药浓度关系的研究。对纳入的研究进行资料提取与质量评价。用Cochrane提供Revman 5.3软件进行Meta分析。结果:有8项研究纳入此次Meta分析,共827例患者。Meta分析结果显示,MDR1C3435T基因型中CT型患者在肾移植术后1周[MD=-16.93,95%CI(-27.67,-6.19),P=0.002]、1月[MD=-18.09,95%CI(-26.41,-9.78),P<0.0001]、6月[MD=-15.52,95%CI(-25.18,-5.85),P=0.002]时,血药浓度高于同期CC型患者;TT型患者在肾移植术后1周[MD=-30.76,95%CI(-53.04,-8.48),P=0.007]、1月[MD=-25.92,95%CI(-48.34,-3.51),P=0.02]、3月[MD=-33.77,95%CI(-48.74,-18.80),P <0.00001]、6月[MD=-22.25,95%CI(-32.97,-11.53),P<0.0001]、12月[MD=-22.74,95%CI(-42.76,-2.72),P=0.03]时,血药浓度高于同期CC型患者;TT型患者在肾移植术后3月[MD=-18.81,95%CI(-34.30,-3.33),P=0.002]时,血药浓度高于同期CT型患者。结论:MDR1C3435T基因多态性与FK506血药浓度/剂量存在相关性,且血药浓度的关系是携带者(CT型或者TT型)>非携带者(CC型)。在肾移植术后不同时期内,根据MDR1C3435T基因多态性与FK506血药浓度/剂量存在的相关性,做基因检测可以在短时间内达到有效血药浓度。由于纳入研究数量较少、样本量不大、该结论有待大样本、高质量研究进一步证实。