CYP2C19 Polymorphisms In Patients Research Articles

Genetic variability in stroke patients: CYP2C19 polymorphisms unraveled

ObjectiveTo study the distribution characteristics of CYP2C19 polymorphisms in patients suffering from stroke in Han Chinese patients.MethodPCR and DNA microarray chip technology were used to detect the CYP2C19 genotype of 549 patients with stroke, and the genotype, allele frequency and metabolic type of patients with different sexes, ages and types of infarctions and the independent risk factors for clopidogrel resistance were analyzed.ResultsSix genotypes were detected in these 549 patients. A total of 233 (42.44%) patients had the heterozygous allele *1/*2, which was the most prevalent, followed by the homozygous wild-type allele *1/*1 (191, 34.79%). A total of 30 (5.46%) patients possessed the heterozygous allele *1/*3, and 65 (11.84%) patients had the homozygous mutant allele *2/*2. Twenty-nine (5.28%) patients had the compound heterozygous mutant allele *2/*3, and only 1 patient had the homozygous mutant allele *3/*3. The distribution of genotypes, alleles, and metabolic types did not change significantly (P > 0.05) by sex, age, or type of stroke. In addition, no independent risk factors for clopidogrel resistance were found in this analysis.ConclusionThe distribution of CYP2C19 genotypes, allele frequencies, and metabolic types in patients with stroke in Han Chinese patients were not correlated with sex, age, or infarction type. The possibilities of hyperglycemia, hypercholesterolemia, hypertriglyceridemia, hypo-HDL-cholesterolemia, hyper-LDL-cholesterolemia and high blood pressure were not statistically associated with CYP2C19 genotypes. CYP2C19 gene polymorphism detection is recommended for patients who are available, and during treatment, the CYP2C19 genotype can be used to guide personalized precise medication use in patients with stroke.

Individualized treatment with voriconazole in the Chinese population: Inflammation level as a novel marker for dose optimization.

The aim of this study was to explore the influence and possible mechanisms of pharmacokinetics-related gene polymorphisms, especially CYP2C19 polymorphisms, and non-genetic factors combined with the inflammatory status on the voriconazole (VRC) metabolism of the Chinese population. Clinical studies were performed by collecting more than one VRC trough concentration and C-reactive protein (CRP) level. A total of 265 blood samples were collected from 120 patients. Results of multiple regression analyses demonstrated that CYP2C19 genotypes and albumin (Alb) level remained predictors of Cmin ss/D in patients with no to mild inflammation (R2 = 0.12, P < .001). In addition, in patients with moderate to severe inflammation, it resulted in a significant model containing factors of CRP and total bilirubin (T-Bil) levels (R2 = 0.19, P < .001). In non-clinical studies, 32 rats were divided into control and inflammatory groups, and it was found that the mean residence time (MRT(0-t) ) of VRC in the inflammatory group was significantly longer than that in the control group (P < .001), which may be due to down-regulation of mRNA and protein expression of CYP2C19 (CYP2C6 in rats) through interleukin (IL)-6/signal transducer and activator of transcription (STAT) 3 pathway. Therefore, the effect of CYP2C19 polymorphisms on VRC metabolism may be masked by inflammatory status, which should be of more concern than CYP2C19 polymorphisms in patients with moderate to severe inflammation. Additionally, the impact of Alb and T-Bil on VRC metabolism should not be disregarded.

The correlation between platelet responsiveness to clopidogrel and CYP2C19 polymorphism in patients with peripheral vascular disease.

Several patients undergoing endovascular intervention and bypass surgery present with high platelet reactivity following clopidogrel treatment. We aimed to determine the frequency of the genetic polymorphism of CYP2C19*2 and the contribution of this polymorphism along with other clinical parameters to clopidogrel response in an Egyptian population. A total of 50 patients receiving clopidogrel at a maintenance dose of 75 mg daily post vascular intervention from January 1, 2019, to May 30, 2020, were enrolled in this study. Clopidogrel resistance was determined through platelet aggregation analysis using Chrono-Log® platelet aggregometer. Single-nucleotide polymorphism (SNP) genotyping was performed using quantitative real-time polymerase chain reaction (QRT-PCR). The incidence of clopidogrel resistance among this Egyptian population is about 22%. Univariate analysis demonstrated that CYP2C19*2 genotype (p = 0.001), high body mass index (BMI; p = 0.025), diabetes (p = 0.037), high fasting blood glucose (FBG) level (p = 0.037), and high glycosylated hemoglobin (HbA1c) level (p = 0.004) were significantly associated with clopidogrel resistance. Multivariate analysis showed that CYP2C19*2 genotype (odds ratio (OR), 927.71; 95% confidence interval (CI), 1.915-449496.2; p = 0.030) and high BMI (OR, 1.789; 95% CI, 1.044-3.064; p = 0.034) were the most powerful predictors of clopidogrel resistance. Clopidogrel resistance in patients with peripheral vascular disease is associated with the presence of CYP2C19*2 allele, obesity, and diabetes; these factors should be considered prior to clopidogrel administration.

3480 Association of Clopidogrel Resistance Determinants and MACE Ocurrence in Peripheral Arterial Disease

OBJECTIVES/SPECIFIC AIMS: The study aims to identify the short and long-term associations of HTPR and presence of CYP2C19 polymorphism in the occurrence of major adverse cardiovascular events (MACE). The primary outcome of the study will be the presence of MACE including stent thrombosis, need for revascularization, acute limb ischemia events, myocardial infarction and death in relation to the presence of HTPR and CYP2C19 polymorphism. Secondary outcomes will include the prevalence of HTPR and CYP2C19 polymorphism in patients with PAD, and association with other medications including aspirin and cilostazol. METHODS/STUDY POPULATION: Patients above 21 years of age with the diagnosis of PAD using clopidogrel therapy for at least for seven days will be recruited at the University of Puerto Rico District Hospital and Cardiovascular Hospital of Puerto Rico and the Caribbean. RESULTS/ANTICIPATED RESULTS: A total of 200 patients from Puertorrican, Dominican and Cuban ethnicity will be expected to be recruited. The most common comorbidities will include, coronary artery disease, hypertension, dyslipidemia, and diabetes mellitus type 2. No significant distr DISCUSSION/SIGNIFICANCE OF IMPACT: The status quo as it pertains to resistance to clopidogrel in PAD patients is to improve antiplatelet resistance using antiplatelet therapy guided by platelet assays in order to reduce MACE occurrence. Although HTPR and presence of CYP2C19 polymorphisms have been studied on the PAD population, currently there is no gold standard test for measuring antiplatelet resistance. In that regard, this study will expect to identify the contribution that HTPR and CYP2C19 polymorphism might have on MACE in patients with PAD. In this way, the results will allow identification of abnormality parameters in HTPR and CYP2C19 testing in relation to the impact on risk of having MACE. Once the association of these variables with MACE is established, testing for clopidogrel resistance could become a potential strategy to optimize antiplatelet therapy and reduce the impact that MACE have in this population.

Clinical Role of CYP2C19 Polymorphisms in Patients with Congenital Adrenal Hyperplasia Due to 21-hydroxylase Deficiency.

Extraadrenal enzymes such as CYP2C19 may participate in residual 21-hydroxylation of progesterone leading to milder phenotypes of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21OHD). Among 94 21OHD patients 28 were homozygous or compound heterozygous for severe CYP21A2 mutations. We have reviewed their clinical phenotype and obtained information on maintenance doses of hydrocortisone and fludrocortisone. All patients were genotyped for CYP2C19*2 and CYP2C19*17 alleles. Eleven patients with CYP2C19*1/*17 genotype had all salt-wasting 21OHD. Among 17 patients with CYP2C19 genotypes leading to normal or decreased CYP2C19 activity, 15 had salt-wasting, one had simple virilizing and one had non-classical 21OHD. CYP2C19*1/*17 genotype was associated with lower maintenance dose of fludrocortisone (p = 0.04), but not of hydrocortisone (p > 0.05). Increased CYP2C19 activity could slightly ameliorate mineralocorticoid deficiency in 21OHD.

Efficacy and safety of voriconazole and CYP2C19 polymorphism for optimised dosage regimens in patients with invasive fungal infections

The aim of this study was to determine an optimum voriconazole target concentration, to study the influence of CYP2C19 gene status on metabolism of voriconazole and to identify a dose-adjustment strategy for voriconazole according to CYP2C19 polymorphism in patients with invasive fungal infections. A total of 328 voriconazole trough plasma concentrations (Cmin) were collected and monitored from 144 patients. Information on efficacy and safety was obtained. Voriconazole therapy was effective in 81.9% of patients (118/144), and 12.5% (18/144) exhibited signs of hepatotoxicity. The relationships between voriconazole Cmin and clinical response and hepatotoxicity were explored using logistic regression, and a target clinical Cmin range of 1.5–4mg/L was identified. Values of voriconazole Cmin and the ratio of Cmin to concentration of voriconazole-N-oxide (Cmin/CN) of poor metabolisers (PMs) were significantly higher than extensive metabolisers and intermediate metabolisers. Model-based simulations showed that PM patients could be safely and effectively treated with 200mg twice daily orally or intravenously, and non-PM patients with 300mg twice daily orally or 200mg twice daily intravenously. This study highlighted that voriconazole Cmin and Cmin/CN are strongly influenced by CYP2C19 polymorphism, and gene-adjusted dosing is important to achieve therapeutic levels that maximise therapeutic response and minimise hepatotoxicity.

Genetic Variations in the Xenobiotic-Metabolizing Enzymes CYP1A1, CYP1A2, CYP2C9, CYP2C19 and Susceptibility to Colorectal Cancer Among Turkish People

Cytochrome P450 (CYP) enzymes are genetically polymorphic and play key roles in the metabolism of xenobiotics. Colorectal cancer (CRC) is one of the most common malignant tumors in Turkey as well as in the world. In this study, it was aimed both to evaluate the effects of CYP variants on the susceptibility to CRC and to predict the individual response of the Turkish people to xenobiotics metabolized by CYP enzymes. For that, we assessed the association of CYP1A1, CYP1A2, CYP2C9, and CYP2C19 polymorphisms in patients with CRC in the Turkish population through a case-control study. Distributions of the variants were determined in 104 patients with CRC and 183 healthy volunteers. As results, CYP1A1 6235T/C was significantly associated with CRC risk (odds ratio [OR]=2.53; 95% confidence interval [CI]=0.99-6.45; p=0.046). In a haplotype-based analysis, CYP1A1 haplotype C6235-A2455 might be associated with the development of CRC (OR=2.70; 95% CI=0.58-5.90; p=0.046). We believe that the findings are the first results of CYP allele distributions in the Turkish population and provide an understanding of the epidemiological studies that correlate therapeutic approaches and etiology of CRC especially in Turkish patients.

The effectiveness of clopidogrel in the prevention of thrombotic complications in patients with acute coronary syndrome and genetic factors

This review article presents the current views on genotyping during administration of clopidogrel - an antiplatelet drug from the class of thienopyridines, for patients with acute coronary syndrome. Highlighted were the data on genetic disorders affecting the absorption and metabolism of clopidogrel. The gene ABCB1 (MDR1) encodes the intestinal transporter P-glycoprotein. The variability of this gene may affect the bioavailability of clopidogrel. However, data on the relationship between C3435T polymorphism of ABCB1 gene and the expression of P-glycoprotein still remain controversial. Differences in the effects of C3435T may reflect the differences in the frequency of ABCB1 polymorphism among ethnic groups and the complex of effects of different polymorphisms in the same gene within a haplotype, or confounding factors of the environment. The most important role in the metabolism of clopidogrel is played by cytochrome P-450 (iso-enzyme CYP2C19). Several large studies have confirmed the prognostic significance of CYP2C19 polymorphism in patients receiving clopidogrel. In a recent meta-analysis of nine pharmacogenetic studies of clopidogrel, which included 9685 patients with acute coronary syndrome, revealed was a significant association between the homozygous and heterozygous alleles with reduced CYP2C19 function and an increased risk of death due to cardiovascular disease, myocardial infarction or stroke. Two large randomized studies of CYP2C19 genotyping did not reveal any relationship between its variants and the occurrence of cardiovascular events in patients with acute coronary syndrome or atrial fibrillation. Thus, in genetic studies of the antiplatelet effectiveness of clopidogrel, there are many uncertainties; domestic data on this subject is extremely scarce.

Role of CYP2C19 polymorphisms in patients with endometriosis

Aim. To investigate the association of CYP2C19 genotypes with endometriosis.Methods. The study included 100 women who underwent laparotomy or laparoscopy: 50 patients with endometriosis diagnosed with surgery and histopathology, and 50 control subjects who had no evidence of endometriosis during exploratory laparotomy or laparoscopy. Genomic DNA of subjects was extracted from the whole blood using High Pure PCR template preparation kit. Genotyping of CYP2C19 polymorphisms were detected by using a LightCycler CYP2C19 mutation detection kit in a real-time PCR, and were compared between the two groups.Results. Logistic regression analyses showed that the CYP2C19*2 heterozygote genotype was associated with a significantly increased risk of endometriosis. The odds ratio of endometriosis for the CYP2C19*2 heterozygote genotype was 3.165 (p = 0.023) compared with the control group. CYP2C19*3 genotype was detected as wild in all subjects in the endometriosis and control groups.Conclusion. Our results suggest that CYP2C19*2 heterozygote genotype has higher risk of developing endometriosis. Therefore, CYP2C19*2 allele gene polymorphisms may be associated with genetic susceptibility of endometriosis.

Cytochrome P450 polymorphisms in patients with Behcet's disease

Although the etiopathogenesis of Behcet's disease (BD) remains unknown, increased neutrophil functions such as chemotaxis, phagocytosis and excessive production of reactive oxygen species, including superoxide anion, may be responsible for the oxidative tissue damage observed in BD. Cytochrome P-450 are a multigene family of enzymes involved in the detoxification and occasional activation of a wide variety of chemicals. Our aim was to investigate CYP2C9 and CYP2C19 polymorphisms in patients with BD. Sixty-two subjects with BD and 107 healthy control subjects were enrolled in the study. Polymorphisms of CYP2C9 and CYP2C19 were performed by real-time PCR with a LightCycler instrument. We researched associations between CYP polymorphisms and BD. The frequencies of wild-type and heterozygous CYP2C19*2 genotypes were 66.1% and 33.9% in the patients and 83.2% and 16.8% in the controls, respectively. There was a 2.53-fold increased risk of Behcet's disease in individuals with the CYP2C19*2 heterozygous genotype (OR = 2.53; 95% CI, 1.22-5.25) when compared with the control group. But the CYP2C9*2, CYP2C9*3 and CYP2C19*3 gene polymorphisms were not related to an increased risk of developing BD. We observed that patients with BD presented with a higher prevalence of the heterozygous CYP2C19*2 genotype. Hereditary deficiencies of this enzyme activity may lead to an imbalance between pro- and antioxidant systems, resulting in the formation of excessive reactive oxygen species.

CYP2C19 Polymorphisms in Patients with Gastric and Colorectal Carcinoma

It has been reported that up to 80% of human cancers arise as a consequence of environmental exposure and host susceptibility factors. Environmental carcinogens are predominantly metabolized by the cytochrome P450 (CYP) superfamily of drug- or xenobiotic-metabolizing enzymes. Genetic variations in these enzymes affect individuals' susceptibility to carcinogens. The aim of this study was to evaluate the relationship between CYP2C19 polymorphism and susceptibility to these cancers by means of CYP2C19 genotyping among Turkish subjects. DNAof subjects were isolated from leukocytes by high pure template preparation kit (Roche Diagnostics, GmbH, Mannheim, Germany) and genotypes were detected by LightCycler CYP2C19 Mutation Detection Kit by real-time PCR with LightCycler instrument (Roche Diagnostics, cat. no. 3113914). Being male was associated with a 3.5-fold (OR: 4.27, CI: 2.27-8.05) and 4.27-fold (OR: 3.50, CI: 1.948-6.301) risk for colorectal and gastric carcinoma, respectively. The CYP2C19*3 heterozygote genotype was not found in either gastric or colorectal carcinoma patients. Although the frequency of CYP2C19*2 heterozygote genotype is high in patients with gastric and colorectal carcinoma, it is not significantly associated with cancer (OR: 1.79, CI: 0.829-3.865 and OR: 1.998, CI: 0.961-4.154, respectively). Although the frequency of CYP2C19*2 heterozygote genotype is high in our patients with gastric and colorectal carcinoma, there is no the relationship between CYP2C19 polymorphism and susceptibility to these cancer.

Effects of omeprazole on intragastric pH and plasma gastrin are dependent on the CYP2C19 polymorphism

Background & Aims: Omeprazole is metabolized by cytochrome P450 (CYP2C19). The activity of this enzyme is polymorphic, with incidences of poor metabolizers (PMs), heterozygous extensive metabolizers (EMs), and homozygous EMs in white populations of 3%, 30%, and 67%, respectively. The importance of the CYP2C19 polymorphism for the effects of omeprazole on intragastric pH and plasma gastrin concentrations has been investigated. Methods: Twenty-five white patients were genotyped for CYP2C19 by allele-specific polymerase chain reaction amplification, and their Helicobacter pylori status was assessed by serology and with immunoblot analysis. Intragastric pH was monitored over 24 hours, and meal-stimulated plasma gastrin concentration was measured over 4 hours (AUC 4h) before (day 0) and during (day 8) treatment with 20 mg omeprazole once daily. Results: Eleven patients were homozygous for the wild-type allele (wt/wt), 12 were heterozygous EMs (wt/mut), and 2 were PMs (mut/mut). Median (95% confidence interval) 24-hour intragastric pH in the heterozygous EM group was 5.5 (range, 5.1–5.9) compared with 3.1 (range, 2.7–3.6) in homozygous EMs (P < 0.0001) at day 8. The percentage of time with intragastric pH > 4 at day 8 was significantly higher in the wt/mut than wt/wt group (72.4% vs. 37.1%; P < 0.0001). H. pylori status had less influence than CYP2C19 on intragastric acidity. Omeprazole treatment increased meal-stimulated plasma gastrin concentrations from day 0 to day 8 in the homozygous EMs and heterozygous EMs by 16% (NS) and 157% (P = 0.002), respectively. In heterozygous EMs, the gastrin increase was more pronounced in the H. pylori–positive group (226%) than H. pylori–negative group (80%; P = 0.02). Conclusions: The effects of omeprazole on intragastric pH and plasma gastrin are dependent on the CYP2C19 polymorphism in patients with acid-related disorders.GASTROENTEROLOGY 2000;119:670-676

Alternative control limits for zero ideal characteristics: G.E. Meek and K.A. Dunning, (Univ of Akron, Ohio, USA)

The aim of this study was to determine an optimum voriconazole target concentration, to study the influence of CYP2C19 gene status on metabolism of voriconazole and to identify a dose-adjustment strategy for voriconazole according to CYP2C19 polymorphism in patients with invasive fungal infections. A total of 328 voriconazole trough plasma concentrations (Cmin) were collected and monitored from 144 patients. Information on efficacy and safety was obtained. Voriconazole therapy was effective in 81.9% of patients (118/144), and 12.5% (18/144) exhibited signs of hepatotoxicity. The relationships between voriconazole Cmin and clinical response and hepatotoxicity were explored using logistic regression, and a target clinical Cmin range of 1.5–4 mg/L was identified. Values of voriconazole Cmin and the ratio of Cmin to concentration of voriconazole-N-oxide (Cmin/CN) of poor metabolisers (PMs) were significantly higher than extensive metabolisers and intermediate metabolisers. Model-based simulations showed that PM patients could be safely and effectively treated with 200 mg twice daily orally or intravenously, and non-PM patients with 300 mg twice daily orally or 200 mg twice daily intravenously. This study highlighted that voriconazole Cmin and Cmin/CN are strongly influenced by CYP2C19 polymorphism, and gene-adjusted dosing is important to achieve therapeutic levels that maximise therapeutic response and minimise hepatotoxicity.