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find Keyword "Cytochrome P450" 4 results
  • Influence of High Activity of CYP2C9 and VKORC on Warfarin Anticoagulation after Heart Valve Replacement

    ObjectiveTo investigate the influence of high activity of CYP2C9 (Cytochrome P450 proteins 2C9)and VKORC (Vitamin K epoxide reductase C)on warfarin anticoagulation of patients after heart valve replacement (HVR). MethodsFrom February 2010 to May 2013, 40 patients with high activity of CYP2C9 and VKORC underwent HVR in the Department of Cardiac Surgery, the First Affiliated Hospital of Zhengzhou University. There were 18 male and 22 female patients with their age of 40-51 (45.18±2.93)years. There were18 patients receiving mitral valve replacement (MVR), 14 patients receiving MVR and tricuspid valvuloplasty (TVP), and 8 patients receiving double valve replacement (DVR). Depen-ding on whether they received preoperative genetic polymorphism detection of CYP2C9 and VKORC1, all the patients were divided into 2 groups with 20 patients in each group. Patients in group A didn't receive preoperative genetic polymorphism detection of CYP2C9 and VKORC1, while patients in group B received preoperative genetic polymorphism detection of CYP2C9 and VKORC1. Postoperatively, periodic examination of international normalized ratio (INR)was performed to adjust warfarin dosage. Time to reach expected INR value and morbidity were collected. All the patients were followed up for 3-12 months after discharge. Monthly telephone follow-up was performed to record INR values, morbidity and general recovery. ResultsPostoperatively, in group A, 2 patients had cerebral infarction, 2 patients had popliteal artery throm-bosis, 1 patient had pulmonary embolism, and 1 patient had thrombosis in the annulus. Expected INR was achieved 15-20 days after warfarin treatment among the other 14 patients without thromboembolism. Three months after surgery, CYP2C9 and VKORC1 gene polymorphism was examined to find 17 patients with positive CYP2C9*1/*1 (*2CC/*3AA)and positive VKORC1-1639 GA, and 3 patients with positive CYP2C9*1/*1 (*2CC/*3AA)and positive VKORC1-1639 GG. In Group B, patients received aspirin (100 mg/d)and low molecular heparin (0.4 ml/d)in addition to warfarin since the second posto-perative day. Expected INR was achieved 5-9 days after warfarin treatment, and then aspirin and low molecular heparin were discontinued. During the 6 months follow-up period, no obvious thromboembolism was found, and only 1 patient had epistaxis who was cured with nasal tamponade. ConclusionPreoperative detection of genetic polymorphisms of CYP2C9 and VKORC1 can provide important guidance for warfarin anticoagulation after HVR.

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  • Research Progress in the Effects of Gene Polymorphisms on Warfarin Maintenance Doses

    Warfarin is one of the most frequently prescribed oral anticoagulant. Many researches have shown that the cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase complex 1 (VKORC1) genotypes have been strongly associated with warfarin maintenance doses. Warfarin maintenance doses can be accurately predicted by use of dosing algorithms including genetic and clinical information. Although several clinical trials demonstrated mixed results, calling into question the utility of this approach. The present data do not support genetic testing to guide warfarin maintenance doses, but in the setting where genotype data are available, use of this approach is reasonable. Ongoing trials are expected to provide more data, and more work is needed to define dosing algorithms that include appropriate variables in minority populations. All these work will further improve the clinical application of genotype-guided warfarin maintenance doses.

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  • Association between CYP1A1 rs4646903 polymorphisms and chronic obstructive pulmonary disease: a meta-analysis

    Objective To summarize the association between CYP1A1 rs4646903 polymorphisms and COPD risk. Methods Systematic literature search was conducted (up to January 2016) in five online databases, ie. PubMed, Embase, China National Knowledge Infrastructure (CNKI), VIP database, and WanFang databases. The strength of association was calculated by odds ratio (OR) and corresponding 95% confidence interval (CI). Results Six case-control studies with 1 050 cases and 1 202 controls were included. This study suggested a significant association between the CYP1A1 rs4646903 polymorphism and COPD risk (CC vs. TT: OR=1.63, 95%CI 1.17-2.27, P=0.004; CC vs. TC+TT: OR=1.62, 95%CI 1.19-2.20, P=0.002). However, there was no significant difference between allele model (C vs. T, OR=1.20, 95%CI 0.95-1.51, P=0.118) and dominant model (CC+TC vs. TT, OR=1.19, 95%CI 0.82-1.72, P=0.366). Conclusions The CYP1A1 rs4646903 polymorphisms might alter the susceptibility of COPD. More well-designed studies with larger sample size are warranted.

    Release date:2017-11-23 02:56 Export PDF Favorites Scan
  • Long term maintenance of cytochrome P450 activity in a cell sheet-based three-dimensional human hepatic model

    Primary human hepatocytes (PHH) are the gold standard of in vitro human liver model for drug screening. However, a problem of culturing PHH in vitro is the rapid decline of cytochrome P450 (CYP450) activity, which plays an important role in drug metabolism. In this study, thermo-responsive culture dishes were used to explore the conditions for murine embryonic 3T3-J2 fibroblasts to form cell sheet. Based on the cell sheet engineering technology, a three-dimensional (3D) “sandwich” co-culture system of 3T3-J2 cell sheet/PHH/collagen gel was constructed. The tissue structure and protein expression of the model section were observed by hematoxylin eosin staining and immunofluorescence staining respectively. Phenacetin and bupropion were used as substrates to determine the activity of CYP450. The contents of albumin and urea in the system were determined by enzyme linked immunosorbent assay (ELISA). The results showed that the complete 3T3-J2 cell sheet could be obtained when the cell seeding density was 1.5×106 /dish (35 mm dish) and the incubation time at low temperature was 60 min. Through cell sheet stacking, a 3D in vitro liver model was developed. Compared with the two-dimensional (2D) model, in the 3D model, the cell-cell and cell-matrix connections were tighter, the activities of cytochrome P450 CYP1A2 and cytochrome P450 CYP2B6 were significantly increased, and the secretion levels of albumin and urea were increased. These indexes could be maintained stably for 21 d. Therefore, cell sheet stacking is helpful to improve the level of liver function of 3D liver model. This model is expected to be used to predict the metabolism of low-clearance drugs in preclinical, which is of great significance for drug evaluation and other studies.

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