目的探究CYP3A4*1G基因型酶活性及多态性对椎管内分娩镇痛中舒芬太尼镇痛效果的影响。方法本研究选取30只10周龄雌性SD大鼠,根据CYP3A4*1G基因型不同分为GG基因型大鼠组、GA基因型大鼠组和AA基因型大鼠组,每组各10只。另选取2018年1—3...目的探究CYP3A4*1G基因型酶活性及多态性对椎管内分娩镇痛中舒芬太尼镇痛效果的影响。方法本研究选取30只10周龄雌性SD大鼠,根据CYP3A4*1G基因型不同分为GG基因型大鼠组、GA基因型大鼠组和AA基因型大鼠组,每组各10只。另选取2018年1—3月就诊于首都医科大学附属北京妇产医院且经产科医师评估可经阴道分娩的100例足月(≥37周)孕妇为研究对象,所有孕妇在最后1次产检时抽取外周静脉血2ml,检测其CYP3A4*1G基因型。根据CYP3A4*1G基因型不同将研究对象分为GG基因型孕妇组(57例)、GA基因型孕妇组(33例)和AA基因型孕妇组(10例)。比较分析不同基因型大鼠的CYP3A4*1G酶活性以及本研究中孕妇与东亚人群中的CYP3A4*1G基因型频率。比较分析各组孕妇不同时间点的舒芬太尼血药浓度,各组均采用随机数字表法抽取5例孕妇,采用高效液相色谱法检测蛛网膜下隙注入舒芬太尼后10min、15min和20min的血药浓度。比较分析各组孕妇于蛛网膜下隙注入舒芬太尼后0h、0.5h、1h和2h的视觉模拟评分法(visual analog score,VAS)评分。记录各组孕妇蛛网膜下隙注入舒芬太尼后1h内的不良反应发生情况。结果与GG基因型大鼠组比较,GA基因型大鼠组和AA基因型大鼠组的CYP3A4*1G酶活性均显著降低(P<0.05)。本研究中的等位基因频率和基因型频率与1000Genomes数据库和gnomAD数据库中的东亚人群比较差异均无显著性(P>0.05)。蛛网膜下隙注入舒芬太尼后10min,三组患者的舒芬太尼血药浓度比较差异均无显著性(P>0.05);蛛网膜下隙注入舒芬太尼后15min和20min,与GG基因型孕妇组比较,GA基因型孕妇组和AA基因型孕妇组的舒芬太尼血药浓度均显著升高(P<0.05)。由于AA基因型孕妇组的例数较少,达不到统计检验效能的要求,因此将AA基因型孕妇组(10例)和GA基因型孕妇组(33例)合并为突变组(43例)进行后续分析。在蛛网膜下隙注入舒芬太尼后的0.5h、1h和2h,突变组的VAS评分均显著低于GG基因型孕妇组(P<0.05)。蛛网膜下隙注入舒芬太尼后1h内,突变组恶心、呕吐、瘙痒和胎心监护异常的不良反应发生率显著高于GG基因型孕妇组(P<0.05)。结论CYP3A4*1G的GA亚型、AA亚型的酶活性显著低于GG亚型,且CYP3A4*1G的突变型均可增加椎管内分娩镇痛中舒芬太尼的血药浓度,从而加强舒芬太尼的镇痛效果,但同时不良反应发生率更高。展开更多
The cytochrome P450 enzyme CYP3A4 is highly expressed in the intestinal mucosa, where it plays a critical role in the first-pass metabolism of orally administered drugs and thereby influences systemic bioavailability ...The cytochrome P450 enzyme CYP3A4 is highly expressed in the intestinal mucosa, where it plays a critical role in the first-pass metabolism of orally administered drugs and thereby influences systemic bioavailability and drug re- sponse. For example, approximately 45% of an oral dose of the sedative/hypnotic agent midazolam can be inactiva- ted by CYP3A4-dependent 1 -and 4-hydroxylation, necessitating a higher oral dose than an intravenous dose to a- chieve adequate pharmacological response. Unfortunately, there is substantial inter- individual variability in the level of CYP3A4 expressed in the small intestine and this contributes to unpredictability in patient response to this drug and the many other high first-pass CYP3A4 substrates. Over the last 20 years, we have sought to identify and characterize genetic and environmental sources of variable intestinal CYP3A4 expression, with the goal of using that information to guide individual drug dosing decisions in clinical practice. Interestingly, unlike some of the other members of the drug-metabolizing human P450 family, there is only limited variation in the CYP3A4 gene and cod- ing or other highly deleterious variants are rare, despite the fact that CYP3A4 activity in vivo is thought to be highly heritable. More common variation, such as the CYP3A4 ＊ 1Gand CYP3A4 ＊ 22alleles, may influence gene expres- sion, but effect sizes are relatively small. Thus, much of our attention today is focused on the regulation of CYP3A4. With colleagues at St Jude Children＇s Research Hospital, we showed that vitamin D is an important reg- ulator of intestinal CYP3 A4 via a vitamin D receptor - mediated process and that its effects may be exerted predomi- nantly in the duodenum and jejunum, where CYP3A4 expression is most prominent. We have postulated that variation in vitamin D levels and its regulation contribute to variation in intestinal CYP3A4 function. The metabo- lism of 25 - hydroxy vitamin D3 （25 OHD3 ） plays a central role in regulating the effects of the hormone in the body and involves both bioaetivation and catabolic processes. The contributions of CYP2R1, CYP27A1, CYP27B1 and CYP24A1 to these processes are well established. Less well defined is the contribution of enzymes like CYP3A4, SUET and UGT that are known primarily for their roles in drug metabolism, but that can also biotransform 25OHD3. We investigated the oxidation and conjugation of 25OHD3 by these enzymes to better understand their contribution to the regulation of 25OHD3 and to certain pathologies such as drug-induced osteomalaeia and altered drug clearance in patients with liver diseaseE4-61. Results from experiments with cultured primary human hepato- eytes indicate that 25OHD3 is rapidly cleared from hepatic tissue through sulfation by SULT2A1, glueuronidation by UGT1A4 and 4-hydroxylation by CYP3A4,with minimal 1 α- and 24-hydroxylation activity. Moreover, perturbation of the CYP3A4 pathway by inducers or inhibitors of the enzyme leads to metabolic switching. Metabolites from these processes circulate in blood, providing a means to test for changes in enzyme function in vivo. Results from studies conducted with healthy volunteers and patients being treated with rifampin for tuberculosis show selective induction of 25OHD3 oxidation to 4β,25（ OH）zD3 by the potent enzyme inducer, with no change in the efficiency of the lot- and 24-hydroxylation reactions. Interestingly, the inductive effect was most obvious in tuberculosis patients supple- mented with vitamin D3 , suggesting additional, positive effects of the hormone on CYP3A4 expression. Preliminary studies in patients with liver disease reveal changes in the sulfation pathway, with greater accumulation of 25OHD3- 3-sulfate in plasma in patients with mild and moderate forms of the disease, despite a reduction in 25OHD3 levels, and reductions in the parent molecule and all metabolites in plasma from patients with severe disease. This raises the possibility of a reduction in biliary secretion of 25OHD3 conjugates in patients with liver disease and accumula- tion in plasma until their synthesis is significantly compromised in late stages of the disease. This mayhelp explain a reduction in the expression of intestinal CYP3A4 that is also observed in patients with moderate and severe liver disease. Moreover, variation in the biliary secretion of 25OHD3 conjugates may contribute to differences in consti- tutive CYP3A4 expression in individuals with normal hepatic and intestinal function. These conjugates can be de- tected in human bile and are converted to 25OHD3 and 1,25（ OH）zD3 and induce the transcription of VDR target genes in an intestinal cell culture model. Ongoing studies suggest that genetic variation in vitamin D regulatory genes, the diet and sunlight exposure all contribute to inter-individual differences in systemic 25OHD3 concentra- tions. It remains to be seen whether these same factors affect intestinal CYP3A4 function and drug response and can be the target of new precision medicine tests in clinical practice.展开更多
文摘目的探究CYP3A4*1G基因型酶活性及多态性对椎管内分娩镇痛中舒芬太尼镇痛效果的影响。方法本研究选取30只10周龄雌性SD大鼠,根据CYP3A4*1G基因型不同分为GG基因型大鼠组、GA基因型大鼠组和AA基因型大鼠组,每组各10只。另选取2018年1—3月就诊于首都医科大学附属北京妇产医院且经产科医师评估可经阴道分娩的100例足月(≥37周)孕妇为研究对象,所有孕妇在最后1次产检时抽取外周静脉血2ml,检测其CYP3A4*1G基因型。根据CYP3A4*1G基因型不同将研究对象分为GG基因型孕妇组(57例)、GA基因型孕妇组(33例)和AA基因型孕妇组(10例)。比较分析不同基因型大鼠的CYP3A4*1G酶活性以及本研究中孕妇与东亚人群中的CYP3A4*1G基因型频率。比较分析各组孕妇不同时间点的舒芬太尼血药浓度,各组均采用随机数字表法抽取5例孕妇,采用高效液相色谱法检测蛛网膜下隙注入舒芬太尼后10min、15min和20min的血药浓度。比较分析各组孕妇于蛛网膜下隙注入舒芬太尼后0h、0.5h、1h和2h的视觉模拟评分法(visual analog score,VAS)评分。记录各组孕妇蛛网膜下隙注入舒芬太尼后1h内的不良反应发生情况。结果与GG基因型大鼠组比较,GA基因型大鼠组和AA基因型大鼠组的CYP3A4*1G酶活性均显著降低(P<0.05)。本研究中的等位基因频率和基因型频率与1000Genomes数据库和gnomAD数据库中的东亚人群比较差异均无显著性(P>0.05)。蛛网膜下隙注入舒芬太尼后10min,三组患者的舒芬太尼血药浓度比较差异均无显著性(P>0.05);蛛网膜下隙注入舒芬太尼后15min和20min,与GG基因型孕妇组比较,GA基因型孕妇组和AA基因型孕妇组的舒芬太尼血药浓度均显著升高(P<0.05)。由于AA基因型孕妇组的例数较少,达不到统计检验效能的要求,因此将AA基因型孕妇组(10例)和GA基因型孕妇组(33例)合并为突变组(43例)进行后续分析。在蛛网膜下隙注入舒芬太尼后的0.5h、1h和2h,突变组的VAS评分均显著低于GG基因型孕妇组(P<0.05)。蛛网膜下隙注入舒芬太尼后1h内,突变组恶心、呕吐、瘙痒和胎心监护异常的不良反应发生率显著高于GG基因型孕妇组(P<0.05)。结论CYP3A4*1G的GA亚型、AA亚型的酶活性显著低于GG亚型,且CYP3A4*1G的突变型均可增加椎管内分娩镇痛中舒芬太尼的血药浓度,从而加强舒芬太尼的镇痛效果,但同时不良反应发生率更高。
文摘The cytochrome P450 enzyme CYP3A4 is highly expressed in the intestinal mucosa, where it plays a critical role in the first-pass metabolism of orally administered drugs and thereby influences systemic bioavailability and drug re- sponse. For example, approximately 45% of an oral dose of the sedative/hypnotic agent midazolam can be inactiva- ted by CYP3A4-dependent 1 -and 4-hydroxylation, necessitating a higher oral dose than an intravenous dose to a- chieve adequate pharmacological response. Unfortunately, there is substantial inter- individual variability in the level of CYP3A4 expressed in the small intestine and this contributes to unpredictability in patient response to this drug and the many other high first-pass CYP3A4 substrates. Over the last 20 years, we have sought to identify and characterize genetic and environmental sources of variable intestinal CYP3A4 expression, with the goal of using that information to guide individual drug dosing decisions in clinical practice. Interestingly, unlike some of the other members of the drug-metabolizing human P450 family, there is only limited variation in the CYP3A4 gene and cod- ing or other highly deleterious variants are rare, despite the fact that CYP3A4 activity in vivo is thought to be highly heritable. More common variation, such as the CYP3A4 ＊ 1Gand CYP3A4 ＊ 22alleles, may influence gene expres- sion, but effect sizes are relatively small. Thus, much of our attention today is focused on the regulation of CYP3A4. With colleagues at St Jude Children＇s Research Hospital, we showed that vitamin D is an important reg- ulator of intestinal CYP3 A4 via a vitamin D receptor - mediated process and that its effects may be exerted predomi- nantly in the duodenum and jejunum, where CYP3A4 expression is most prominent. We have postulated that variation in vitamin D levels and its regulation contribute to variation in intestinal CYP3A4 function. The metabo- lism of 25 - hydroxy vitamin D3 （25 OHD3 ） plays a central role in regulating the effects of the hormone in the body and involves both bioaetivation and catabolic processes. The contributions of CYP2R1, CYP27A1, CYP27B1 and CYP24A1 to these processes are well established. Less well defined is the contribution of enzymes like CYP3A4, SUET and UGT that are known primarily for their roles in drug metabolism, but that can also biotransform 25OHD3. We investigated the oxidation and conjugation of 25OHD3 by these enzymes to better understand their contribution to the regulation of 25OHD3 and to certain pathologies such as drug-induced osteomalaeia and altered drug clearance in patients with liver diseaseE4-61. Results from experiments with cultured primary human hepato- eytes indicate that 25OHD3 is rapidly cleared from hepatic tissue through sulfation by SULT2A1, glueuronidation by UGT1A4 and 4-hydroxylation by CYP3A4,with minimal 1 α- and 24-hydroxylation activity. Moreover, perturbation of the CYP3A4 pathway by inducers or inhibitors of the enzyme leads to metabolic switching. Metabolites from these processes circulate in blood, providing a means to test for changes in enzyme function in vivo. Results from studies conducted with healthy volunteers and patients being treated with rifampin for tuberculosis show selective induction of 25OHD3 oxidation to 4β,25（ OH）zD3 by the potent enzyme inducer, with no change in the efficiency of the lot- and 24-hydroxylation reactions. Interestingly, the inductive effect was most obvious in tuberculosis patients supple- mented with vitamin D3 , suggesting additional, positive effects of the hormone on CYP3A4 expression. Preliminary studies in patients with liver disease reveal changes in the sulfation pathway, with greater accumulation of 25OHD3- 3-sulfate in plasma in patients with mild and moderate forms of the disease, despite a reduction in 25OHD3 levels, and reductions in the parent molecule and all metabolites in plasma from patients with severe disease. This raises the possibility of a reduction in biliary secretion of 25OHD3 conjugates in patients with liver disease and accumula- tion in plasma until their synthesis is significantly compromised in late stages of the disease. This mayhelp explain a reduction in the expression of intestinal CYP3A4 that is also observed in patients with moderate and severe liver disease. Moreover, variation in the biliary secretion of 25OHD3 conjugates may contribute to differences in consti- tutive CYP3A4 expression in individuals with normal hepatic and intestinal function. These conjugates can be de- tected in human bile and are converted to 25OHD3 and 1,25（ OH）zD3 and induce the transcription of VDR target genes in an intestinal cell culture model. Ongoing studies suggest that genetic variation in vitamin D regulatory genes, the diet and sunlight exposure all contribute to inter-individual differences in systemic 25OHD3 concentra- tions. It remains to be seen whether these same factors affect intestinal CYP3A4 function and drug response and can be the target of new precision medicine tests in clinical practice.
