Association between gene polymorphisms and initial warfarin therapy in patients after heart valve surgery.

BACKGROUND: Warfarin is widely used for the prevention and treatment of thrombotic events. This study aimed to examine the influence of gene polymorphisms on the early stage of warfarin therapy in patients following heart valve surgery. METHODS: Nine single nucleotide polymorphisms were genotyped using microarray chips, categorizing patients into three groups: normal responders (Group I), sensitive responders (Group II), and highly sensitive responders (Group III). The primary clinical outcomes examined were time in therapeutic range (TTR) and international normalized ratio (INR) variability. To investigate potential influencing factors, a generalized linear regression model was employed. RESULTS: Among 734 patients, the prevalence of CYP2C9*3-1075A > C, CYP2C19*3-636G > A, and CYP2C19*17-806C > T variants were 11.2%, 9.9%, and 1.9% of patients, respectively. VKORC1-1639G > A or the linked -1173C > T variant was observed in 99.0% of the patients. Generalized linear model analysis revealed an impact of sensitivity grouping on INR variability. Compared to Group I, Group II showed higher TTR values (p = 0.023), while INR variability was poorer in Group II (p < 0.001) and Group III (p < 0.001). Individual gene analysis identified significant associations between CYP2C9*3-1075A > C (p < 0.001), VKORC1-1639G > A or the linked -1173 C > T (p = 0.009) and GGCX-3261G > A (p = 0.019) with INR variability. CONCLUSION: The genotypes of CYP2C9, VKORC1, and GGCX were found to have a significant impact on INR variability during the initial phase of warfarin therapy. However, no significant association was observed between TTR and gene polymorphisms. These findings suggest that focusing on INR variability is crucial in clinical practice, and preoperative detection of gene polymorphisms should be considered to assist in the initiation of warfarin therapy.

Genetic diversity of variants involved in drug response among Tunisian and Italian populations toward personalized medicine.

Adverse drug reactions (ADR) represent a significant contributor to morbidity and mortality, imposing a substantial financial burden. Genetic ancestry plays a crucial role in drug response. The aim of this study is to characterize the genetic variability of selected pharmacogenes involved with ADR in Tunisians and Italians, with a comparative analysis against global populations. A cohort of 135 healthy Tunisians and 737 Italians were genotyped using a SNP array. Variants located in 25 Very Important Pharmacogenes implicated in ADR were extracted from the genotyping data. Distribution analysis of common variants in Tunisian and Italian populations in comparison to 24 publicly available worldwide populations was performed using PLINK and R software. Results from Principle Component and ADMIXTURE analyses showed a high genetic similarity among Mediterranean populations, distinguishing them from Sub-Saharan African and Asian populations. The Fst comparative analysis identified 27 variants exhibiting significant differentiation between the studied populations. Among these variants, four SNPs rs622342, rs3846662, rs7294, rs5215 located in SLC22A1, HMGCR, VKORC1 and KCNJ11 genes respectively, are reported to be associated with ethnic variability in drug responses. In conclusion, correlating the frequencies of genotype risk variants with their associated ADRs would enhance drug outcomes and the implementation of personalized medicine in the studied populations.

Precision medicine in cardiovascular therapeutics: Evaluating the role of pharmacogenetic analysis prior to drug treatment.

Pharmacogenomics is the examination of how genetic variation influences drug metabolism and response, in terms of both efficacy and safety. In cardiovascular disease, patient-specific diplotypes determine phenotypes, thereby influencing the efficacy and safety of drug treatments, including statins, antiarrhythmics, anticoagulants and antiplatelets. Notably, polymorphisms in key genes, such as CYP2C9, CYP2C19, VKORC1 and SLCO1B1, significantly impact the outcomes of treatment with clopidogrel, warfarin and simvastatin. Furthermore, the CYP2C19 polymorphism influences the pharmacokinetics and safety of the novel hypertrophic cardiomyopathy inhibitor, mavacamten. In this review, we critically assess the clinical application of pharmacogenomics in cardiovascular disease and delineate present and future utilization of pharmacogenomics. This includes insights into identifying missing heritability, the integration of whole genome sequencing and the application of polygenic risk scores to enhance the precision of personalized drug therapy. Our discussion encompasses health economic analyses that underscore the cost benefits associated with pre-emptive genotyping for warfarin and clopidogrel treatments, albeit acknowledging the need for further research in this area. In summary, we contend that cardiovascular pharmacogenomic analyses are underpinned by a wealth of evidence, and implementation is already occurring for some of these gene-drug pairs, but as with any area of medicine, we need to continually gather more information to optimize the use of pharmacogenomics in clinical practice.

Model-Based Prediction of Irinotecan-Induced Grade 4 Neutropenia in Cancer Patients: Influence of Incorporating Germline Genetic Factors in the Model.

Neutropenia is the major dose-limiting toxicity of irinotecan-based therapy. The objective of this study was to assess whether inclusion of germline genetic variants into a population pharmacokinetic/pharmacodynamic model can improve prediction of irinotecan-induced grade 4 neutropenia and identify novel variants of clinical value. A semimechanistic population pharmacokinetic/pharmacodynamic model was used to predict neutrophil response over time in 197 patients receiving irinotecan. Covariate analysis was performed for demographic/clinical factors and 4,781 genetic variants in 84 drug response- and toxicity-related genes to identify covariates associated with neutrophil response. We evaluated the predictive value of the model for grade 4 neutropenia reflecting different clinical scenarios of available data on identified demographic/clinical covariates, baseline and post-treatment absolute neutrophil counts (ANCs), individual pharmacokinetics, and germline genetic variation. Adding 8 genetic identified covariates (rs10929302 (UGT1A1), rs1042482 (DPYD), rs2859101 (HLA-DQB3), rs61754806 (NR3C1), rs9266271 (HLA-B), rs7294 (VKORC1), rs1051713 (ALOX5), and ABCB1 rare variant burden) to a model using only baseline ANCs improved prediction of irinotecan-induced grade 4 neutropenia from area under the receiver operating characteristic curve (AUC-ROC) of 50-64% (95% confidence interval (CI), 54-74%). Individual pharmacokinetics further improved the prediction to 74% (95% CI, 64-84%). When weekly ANC was available, the identified covariates and individual pharmacokinetics yielded no additional contribution to the prediction. The model including only ANCs at baseline and at week 1 achieved an AUC-ROC of 78% (95% CI, 69-88%). Germline DNA genetic variants may contribute to the prediction of irinotecan-induced grade 4 neutropenia when incorporated into a population pharmacokinetic/pharmacodynamic model. This approach is generalizable to drugs that induce neutropenia and ultimately allows for personalized intervention to enhance patient safety.

Synergy of Mutation-Induced Effects in Human Vitamin K Epoxide Reductase: Perspectives and Challenges for Allo-Network Modulator Design.

The human Vitamin K Epoxide Reductase Complex (hVKORC1), a key enzyme transforming vitamin K into the form necessary for blood clotting, requires for its activation the reducing equivalents delivered by its redox partner through thiol-disulfide exchange reactions. The luminal loop (L-loop) is the principal mediator of hVKORC1 activation, and it is a region frequently harbouring numerous missense mutations. Four L-loop hVKORC1 mutants, suggested in vitro as either resistant (A41S, H68Y) or completely inactive (S52W, W59R), were studied in the oxidised state by numerical approaches (in silico). The DYNASOME and POCKETOME of each mutant were characterised and compared to the native protein, recently described as a modular protein composed of the structurally stable transmembrane domain (TMD) and the intrinsically disordered L-loop, exhibiting quasi-independent dynamics. The DYNASOME of mutants revealed that L-loop missense point mutations impact not only its folding and dynamics, but also those of the TMD, highlighting a strong mutation-specific interdependence between these domains. Another consequence of the mutation-induced effects manifests in the global changes (geometric, topological, and probabilistic) of the newly detected cryptic pockets and the alternation of the recognition properties of the L-loop with its redox protein. Based on our results, we postulate that (i) intra-protein allosteric regulation and (ii) the inherent allosteric regulation and cryptic pockets of each mutant depend on its DYNASOME; and (iii) the recognition of the redox protein by hVKORC1 (INTERACTOME) depend on their DYNASOME. This multifaceted description of proteins produces "omics" data sets, crucial for understanding the physiological processes of proteins and the pathologies caused by alteration of the protein properties at various "omics" levels. Additionally, such characterisation opens novel perspectives for the development of "allo-network drugs" essential for the treatment of blood disorders.

Association between polymorphisms of the VKORC1 and CYP2C9 genes and warfarin maintenance dose in Peruvian patients.

AIMS: The aim of this study was to investigate the association between VKORC1 and CYP2C9 genes polymorphisms and the maintenance dose of warfarin in Peruvian patients. METHODS: An observational study was conducted on outpatients from the Hospital Grau ESSALUD in Lima, Peru. The participants were selected using nonprobabilistic convenience sampling. Inclusion criteria required patients to have been on anticoagulation therapy for >3 months, maintain stable doses of warfarin (consistent dose for at least 3 outpatient visits), and maintain an international normalized ratio within the therapeutic range of 2.5-3.5. DNA samples were obtained from peripheral blood for gene analysis. RESULTS: Seventy patients (mean age of 69.6 ± 13.4 years, 45.7% female) were included in the study. The average weekly warfarin dose was 31.6 ± 15.2 mg. The genotypic frequencies of VKORC1 were as follows: 7.1% (95% confidence interval, 2.4-15.9) for AA; 44.3% (32.4-56.7) for GA; and 48.6% (36.4-60.8) for GG. No deviation from the Hardy-Weinberg equilibrium was observed in the variants studied (P = .56). The mean weekly warfarin doses for AA, GA and GG genotypes were 16.5 ± 2.9, 26.5 ± 9.5 and 37.9 ± 17.1 mg, respectively (P < .001). The genotypic frequencies of CYP2C9 were as follows: 82.8% (72.0-90.8) for CC (*1/*1); 4.3% (1.0-12.0) for CT (*1/*2); and 12.9% (6.1-23.0) for TT (*2/*2). We did not find a significant association between the CYP2C9 gene polymorphism and the dose of warfarin. CONCLUSIONS: The AA genotype of the VKORC1 gene was associated with a lower maintenance dose of warfarin in Peruvian patients.

New insights into the role of VKORC1 polymorphisms for optimal warfarin dose selection in Caribbean Hispanic patients through an external validation of a population PK/PD model.

Warfarin, an oral anticoagulant, has been used for decades to prevent thromboembolic events. The complex interplay between CYP2C9 and VKORC1 genotypes on warfarin PK and PD properties is not fully understood in special sub-groups of patients. This study aimed to externally validate a population pharmacokinetic/pharmacodynamic (PK/PD) model for the effect of warfarin on international normalized ratio (INR) and to evaluate optimal dosing strategies based on the selected covariates in Caribbean Hispanic patients. INR, and CYP2C9 and VKORC1 genotypes from 138 patients were used to develop a population PK/PD model in NONMEM. The structural definition of a previously published PD model for INR was implemented. A numerical evaluation of the parameter-covariate relationship was performed. Simulations were conducted to determine optimal dosing strategies for each genotype combinations, focusing on achieving therapeutic INR levels. Findings revealed elevated IC50 for G/G, G/A, and A/A VKORC1 haplotypes (11.76, 10.49, and 9.22 mg/L, respectively), in this population compared to previous reports. The model-guided dosing analysis recommended daily warfarin doses of 3-5 mg for most genotypes to maintain desired INR levels, although subjects with combination of CYP2C9 and VKORC1 genotypes * 2/* 2-, * 2/* 3- and * 2/* 5-A/A would require only 1 mg daily. This research underscores the potential of population PK/PD modeling to inform personalized warfarin dosing in populations typically underrepresented in clinical studies, potentially leading to improved treatment outcomes and patient safety. By integrating genetic factors and clinical data, this approach could pave the way for more effective and tailored anticoagulation therapy in diverse patient groups.

Kinetic-pharmacodynamic model of warfarin for prothrombin time-international normalized ratio in Japanese patients.

AIMS: Genotype-guided dosing algorithms can explain about half of the interindividual variability in prothrombin time-international normalized ratio (PT-INR) under warfarin treatment. This study aimed to refine a published kinetic-pharmacodynamic model and guide warfarin dosage for an optimal PT-INR based on renal function. METHODS: Using a retrospective cohort of adult patients (>20 years) who were administered warfarin and underwent PT-INR measurements, we refined the kinetic-pharmacodynamic model with age and the genotypes of cytochrome P450 2C9 and vitamin K epoxide reductase complex subunit 1 using the PRIOR subroutine in the nonlinear-mixed-effect modelling programme. We searched the significant covariates for parameters, such as the dose rate for 50% inhibition of coagulation (EDR50 ), using a stepwise forward and backward method. Monte Carlo simulation determined a required daily dose of warfarin with a target range of PT-INR (2.0-3.0 or 1.6-2.6) based on the significant covariates. RESULTS: A total of 350 patients with 2762 PT-INR measurements were enrolled (estimated glomerular filtration rate [eGFR]: 47.5 [range: 2.6-199.0] mL/min/1.73 m2 ). The final kinetic-pharmacodynamic model showed that the EDR50 changed power functionally with body surface area, serum albumin level and eGFR. Monte Carlo simulation revealed that a lower daily dose of warfarin was required to attain the target PT-INR range as eGFR decreased. CONCLUSIONS: Model-informed precision dosing of warfarin is a valuable approach for estimating its dosage in patients with renal impairment.

Frequencies of VKORC1-1639G>A and rs397509427 in Patients on Warfarin and Healthy Syrian Subjects.

Background: Vitamin K epoxide reductase complex subunit 1 (VKORC1) gene encodes a key enzyme with multiple cellular activities, namely, the reduction of vitamin K to its active form. VKORC1-1639G>A (rs9923231) is a common single nucleotide polymorphism with a crucial impact on warfarin dosing and possibly other physiological functions. This study aimed at investigating the frequencies of VKORC1-1639G>A alleles and genotypes in Syrian healthy subjects and patients on warfarin for different indications. Methods: A total of 138 individuals were enrolled in this cross-sectional study. Genomic DNA was extracted from both patients on warfarin and healthy subjects, and polymerase chain reaction (PCR) specific amplicons were genotyped via standard sequencing which also allowed the detection of rs397509427. Comparisons of -1639G>A frequency with other populations were drawn. Results: Of 94 patients on warfarin, 53 (56.38%) were with idiopathic venous thromboembolism (VTE). Despite comparable frequencies of the -1639A allele (47% and 50%), the AA and GA genotypes were at disparate frequencies of 93.2% versus 79.8% in the healthy subjects (n = 44) versus patients on warfarin, respectively. Carriers of the GG genotype were at a four-fold increased risk of VTE in comparison with those of the AA and GA genotypes (odds ratio (OR) = 4, 95% CI = 1.105 - 13.6, P = 0.0469). All study subjects were wild-type for the rs397509427 variant. Conclusions: Our results prove a high -1639A prevalence in Syrian healthy subjects and patients on warfarin at frequencies comparable to other Mediterranean and Middle Eastern populations. The A allele carriers are at a lower VTE risk, whereas a global prevalence gradient of the G allele is suggested to be associated with VTE risk.

Acute kidney injury interacts with VKORC1 genotype on initiative warfarin dose among heart surgery recipients: a real-world research.

Patients who receive heart valve surgery need anticoagulation prophylaxis to reduce the risk of thrombosis. Warfarin often is a choice but its dosage varies due to gene and clinical factors. We aim to study, among them, if there is an interaction between acute kidney injury and two gene polymorphisms from this study. We extracted data of heart valve surgery recipients from the electronic health record (EHR) system of a medical center. The primary outcome is about the average daily dose of warfarin, measured as an additive interaction effect (INTadd) between acute kidney injury (AKI) and warfarin-related gene polymorphisms. The confounders, including age, sex, body surface area (BSA), comorbidities (i.e., atrial fibrillation [AF], hypertension [HTN], congestive heart failure [CHF]), serum albumin level, warfarin-relevant gene polymorphism (i.e., CYP2C9, VKORC1), prosthetic valve type (i.e., metal, bio), and warfarin history were controlled via a multivariate-linear regression model. The study included 200 patients, among whom 108 (54.00%) are female. Further, the mean age is 54.45 years, 31 (15.50%) have CHF, and 40 (20.00%) patients were prescribed concomitant amiodarone, which potentially overlays with the warfarin prophylaxis period. During the follow-up, AKI occurred in 30 (15.00%) patients. VKORC1 mutation (1639G>A) occurred in 25 (12.50%) patients and CYPC29 *2 or *3 mutations presented in 20 patients (10.00%). We found a significant additive interaction effect between AKI and VKORC1 (- 1.17, 95% CI - 1.82 to - 0.53, p = 0.0004). This result suggests it is probable that there is an interaction between acute kidney injury and the VKORC1 polymorphism for the warfarin dose during the initial period of anticoagulation prophylaxis.

Association among VKORC1 rs9923231, CYP4F2 rs2108622, GGCX rs11676382 polymorphisms and acute ischemic stroke.

Acute ischemic stroke is a major cause of morbidity and mortality worldwide, and genetic factors play a role in the risk of stroke. Single nucleotide polymorphisms (SNPs) in the VKORC1, CYP4F2, and GGCX genes have been linked to clinical outcomes, such as bleeding and cardiovascular diseases. This study aimed to investigate the association between specific polymorphisms in these genes and the risk of developing the first episode of acute ischemic stroke in patients without a known embolic source. This retrospective, cross-sectional, observational, analytical, case-control study included adult patients diagnosed with acute ischemic stroke. The SNPs in VKORC1 rs9923231, CYP4F2 rs2108622, GGCX rs11676382 genes were genotyped and analyzed together with the demographic and clinical factors of the 2 groups of patients. The presence of SNPs in VKORC1 or CYP4F2 genes significantly increased the risk of ischemic stroke in the context of smoking, arterial hypertension, and carotid plaque burden. The multivariate logistic model revealed that smoking (odds ratio [OR] = 3.920; P < .001), the presence of carotid plaques (OR = 2.661; P < .001) and low-density lipoprotein cholesterol values >77 mg/dL (OR = 2.574; P < .001) were independently associated with stroke. Polymorphisms in the VKORC1 and CYP4F2 genes may increase the risk of ischemic stroke in patients without a determined embolic source. Smoking, the presence of carotid plaques, and high low-density lipoprotein cholesterol levels were reconfirmed as important factors associated with ischemic stroke.

Exploring the complex relationship between vitamin K, gut microbiota, and warfarin variability in cardiac surgery patients.

BACKGROUND AND OBJECTIVES: Due to the high individual variability of anticoagulant warfarin, this study aimed to investigate the effects of vitamin K concentration and gut microbiota on individual variability of warfarin in 246 cardiac surgery patients. METHODS: The pharmacokinetics and pharmacodynamics (PKPD) model predicted international normalized ratio (INR) and warfarin concentration. Serum and fecal samples were collected to detect warfarin and vitamin K [VK1 and menaquinone-4 (MK4)] concentrations and gut microbiota diversity, respectively. In addition, the patient's medical records were reviewed for demographic characteristics, drug history, and CYP2C9, VKORC1, and CYP4F2 genotypes. RESULTS: The PKPD model predicted ideal values of 62.7% for S-warfarin, 70.4% for R-warfarin, and 76.4% for INR. The normal VK1 level was 1.34±1.12 nmol/ml (95% CI: 0.33-4.08 nmol/ml), and the normal MK4 level was 0.22±0.18 nmol/ml (95% CI: 0.07-0.63 nmol/ml). The MK4 to total vitamin K ratio was 16.5±9.8% (95% CI: 4.3-41.5%). The S-warfarin concentration of producing 50% of maximum anticoagulation and the half-life of prothrombin complex activity tended to increase with vitamin K. Further, Prevotella and Eubacterium of gut microbiota identified as the main bacteria associated with individual variability of warfarin. The results suggest that an increase in vitamin K concentration can decrease anticoagulation, and gut microbiota may influence warfarin anticoagulation through vitamin K2 synthesis. CONCLUSION: This study highlights the importance of considering vitamin K concentration and gut microbiota when prescribing warfarin. The findings may have significant implications for the personalized use of warfarin. Further research is needed to understand better the role of vitamin K and gut microbiota in warfarin anticoagulation.

Widespread distribution of rodenticide resistance-conferring mutations in the Vkorc1 gene among house mouse populations in Portuguese Macaronesian islands and Iberian Atlantic areas.

Growing evidence of widespread resistance to anticoagulant rodenticides (ARs) in house mice pose significant challenges to pest control efforts. First-generation ARs were introduced in the early 1950s but resistance to these emerged later that decade. Second-generation rodenticides were then developed, with resistance being reported in the late 1970s. Research has linked resistance to ARs with mutations in the Vkorc1 gene, leading to the use of more toxic and environmentally harmful compounds. In this study, 243 tail tips of house mice from mainland Portugal and Southern Spain, the Azores and Madeira archipelagos were analysed for all 3 exons of the Vkorc1 gene. Mutations L128S, Y139C, along with the so-called spretus genotype Vkorc1spr are considered responsible for reduced susceptibility of house mice to ARs. All these sequence variants were broadly detected throughout the sampling regions. Vkorc1spr was the most often recorded among mainland populations, whereas Y139C was nearly ubiquitous among the insular populations. In contrast, L128S was only detected in mainland Portugal and four islands of the Azores archipelago. All first generation ARs such as warfarin and coumatetralyl are deemed ineffective against all Vkorc1 variants identified in this study. Second-generation bromadiolone and difenacoum should also be discarded to control populations carrying Vkorc1spr, Y139C or L128S mutations. Inadequate use of ARs in regions where resistant animals have been found in large proportions will result in the spreading of rodenticide resistance among rodent populations through the positive selection of non-susceptible individuals. Consequently, ineffectiveness of rodent control will increase and potentiate environmental contamination, hazarding non-target wildlife through secondary poisoning. We highlight the need for Vkorc1 screening as a crucial tool in rodent management, aiding in the selection of the most appropriate control/eradication method in order to prevent misuse of these toxic biocides and the spread of rodenticide resistance among house mouse populations.

Warfarin pharmacogenetics in a black Zimbabwean cohort: an observational prospective study.

Aim: A prospective observational study was conducted to evaluate the feasibility of implementing clinical guidelines for warfarin dosing in black Zimbabwean patients. Methods: CYP2C9*5, CYP2C9*6, CYP2C9*8 and CYP2C9*11 and VKORC1 c. 1639 G>A variations were observed in 62 study patients. Results & Conclusion: Overall, 39/62 (62.90%) participants did not receive a warfarin starting dose as would have been recommended by Clinical Pharmacogenetics Implementation Consortium guidelines. US FDA and Dutch Pharmacogenetics Working Group guidelines are based on CYP2C9*2 and CYP2C9*3 only, hence, unlikely useful in this cohort, where such variants were not detected. Clinical Pharmacogenetics Implementation Consortium guidelines, on the other hand, have a specific recommendation on the African-specific variants CYP2C9*5, CYP2C9*6 and CYP2C9*11, and are hence suitable for implementation in Zimbabwe and would help optimize warfarin doses in patients in the study cohort.

Optimisation of warfarin-dosing algorithms for Han Chinese patients with CYP2C9*13 variants.

BACKGROUND: Existing pharmacogenetic algorithms cannot fully explain warfarin dose variability in all patients. CYP2C9*13 is an important allelic variant in the Han Chinese population. However, adjustment of warfarin dosing in CYP2C9*13 variant carriers remains unclear. To the best of our knowledge, this study is the first to assess the effects of adjusting warfarin dosages in Han Chinese patients harbouring CYP2C9*13 variants. METHODS: In total, 971 warfarin-treated Han Chinese patients with atrial fibrillation were enrolled in this study. Clinical data were collected, and CYP2C9*2, *3, *13 and VKORC1-1639 G > A variants were genotyped. We quantitatively analysed the effect of CYP2C9*13 on warfarin maintenance dose and provided multiplicative adjustments for CYP2C9*13 using validated pharmacogenetic algorithms. RESULTS: Approximately 0.6% of the Han Chinese population carried CYP2C9*13 variant, and the genotype frequency was between those of CYP2C9*2 and CYP2C9*3. The warfarin maintenance doses were significantly reduced in CYP2C9*13 carriers. When CYP2C9*13 variants were not considered, the pharmacogenetic algorithms overestimated warfarin maintenance doses by 1.03-1.16 mg/d on average. The actual warfarin dose in CYP2C9*13 variant carriers was approximately 40% lower than the algorithm-predicted dose. Adjusting the warfarin-dosing algorithm according to the CYP2C9*13 allele could reduce the dose prediction error. CONCLUSION: Our study showed that the algorithm-predicted doses should be lowered for CYP2C9*13 carriers. Inclusion of the CYP2C9*13 variant in the warfarin-dosing algorithm tends to predict the warfarin maintenance dose more accurately and improves the efficacy and safety of warfarin administration in Han Chinese patients.

Frequency of polymorphisms in the CYP2C9, VKORC1, and CYP4F2 genes related to the metabolism of Warfarin in healthy donors from Cali, Colombia.

Alleles in the VKORC1, CYP2C9, and CYP4F2 genes can influence Warfarin dose requirement. We aimed to determine the frequency of the polymorphisms in these genes in healthy individuals from Cali, Colombia. Observational study where total blood was collected from 107 healthy donors who attended a higher educational institution in Cali, Colombia. Sanger sequencing of exons 2, 3, 5, and 7 of the CYP2C9 gene; the common promoter region of CYP (rs12777823); exon 11 of CPY4F2 and the polymorphism c.-1639G > A in the VKORC1 gene promoter was performed. CYP2C9*2, CYP2C9*3, CYP2C9*8, CYP2C9*9, CYP2C9*11, CYP4F2*3, rs12777823, and VKORC1*2 were detected. The latter had the highest frequency with 80 (74.8%) participants in a heterozygous or homozygous state. The least frequent allele was CYP2C9*11 with only 1 carrier. Combined haplotypes (VKORC1 *1/*2 or *2/*2 and CYP2C9 *1/*2 or *2/*2) were identified in 14 (13.7%) subjects. Both frequencies found in the VKORC1 and CYP2C9 alleles were similar to the ones reported for Latin Americans of European and Native American Ancestry. VKORC1*2 allele, the main genetic contributor to Warfarin dosing requirement, was the variant with the highest frequency (74.8% subjects, with a frequency of the alternative allele (A) of 50%). Our findings provide researchers with a greater insight regarding the frequency of common polymorphisms that affect anticoagulation treatment in the Cali (Colombia) population.

FREQUENCY OF VKORC1 AND CYP2C9 GENES POLYMORPHISM IN ABKHAZIAN POPULATION.

The aim of the research was to study the frequency of VKROC1 and CYP2C9 genes different alleles for healthy donors and for patients with thrombosis, in Abkhazian population and to reveal the interdependence of the studied genes products in the treatment of thrombosis with warfarin. Warfarin is an anticoagulant, causing the inactivation of the VKORC1 gene product, which is one of the clotting factors. The protein product of CYP2C9 gene is involved in the metabolism of warfarin. Genotyping of blood samples for studied genes alleles was carried out using a tube scanner (ESE Quant Tube Scaner), allowing to identify SNPs. With the highest frequency in the studied group of healthy donors of Abkhazian population, by VKROC1 gene found Heterozygous (AG genotype) (74,5 %). The distribution of homozygous of "wild" (GG) and mutant genotype (AA) accounted for 13,5% and 11,8%, respectively. In the group of patients with Thrombosis, wild-type homozygotes accounted for 32.5%, which is significantly high compared to the control group. The percentage of heterozygotes was significantly lower than in the control group and accounted 56,25%. as for the homozygous mutant genotype, it was practically the same as in control group (11,2%). Regarding the rate of polymorphic variants of the CYP2C9 gene, quite large differences between diseased and healthy individuals were detected according to some of them. CYP2C9 *1/*1 genotype (wild- type homozygote) was observed in 32.9% of healthy individuals, while the same genotype was detected in only 14.5% of patients with thrombosis. The percentage of CYP2C9 *1/*2 genotype was slightly different between healthy and thrombotic subjects and corresponded to 27.5% in healthy individuals and 30.4% in thrombotic patients. CYP2C9 *1/*3 genotype accounted for 16.1% in healthy individuals. The mentioned indicator was significantly different from the similar indicator of patients with thrombosis, which corresponded to 24.1%. The largest difference between the percentages was observed according to the CYP2C9 *2/*3 (mutant heterozygote) genotype. In healthy individuals, this rate corresponded to 40.3%, and in thrombotic individuals - 11.4%. The CYP2C9 *2/*2 genotype was not observed in any of the study groups, while the percentage of CYP2C9 *3/*3 (mutant homozygous) individuals did not differ and amounted to 1.6% (in healthy individuals) and 1.2% (in thrombotic patients). VKORC1 and / or CYP2C9 genes polymorphisms are presented in a number of clinical dosing algorithms and in prospective clinical trials. In conclusion, it should be noted that the present work revealed a significant variability of genotypes between the groups of patients with thrombosis and healthy individuals, in Abkhazian population. The results obtained in determining the polymorphic variants of the VKORC1 and CYP2C9 genes, studied by us, should be taken into account when using algorithms to determine the optimal dosage for warfarin treatment in thrombotic individuals of the Abkhazian population, both during treatment and for the prevention of thrombosis.

Regulation of VKORC1L1 is critical for p53-mediated tumor suppression through vitamin K metabolism.

Here, we identified vitamin K epoxide reductase complex subunit 1 like 1 (VKORC1L1) as a potent ferroptosis repressor. VKORC1L1 protects cells from ferroptosis by generating the reduced form of vitamin K, a potent radical-trapping antioxidant, to counteract phospholipid peroxides independent of the canonical GSH/GPX4 mechanism. Notably, we found that VKORC1L1 is also a direct transcriptional target of p53. Activation of p53 induces downregulation of VKORC1L1 expression, thus sensitizing cells to ferroptosis for tumor suppression. Interestingly, a small molecular inhibitor of VKORC1L1, warfarin, is widely prescribed as an FDA-approved anticoagulant drug. Moreover, warfarin represses tumor growth by promoting ferroptosis in both immunodeficient and immunocompetent mouse models. Thus, by downregulating VKORC1L1, p53 executes the tumor suppression function by activating an important ferroptosis pathway involved in vitamin K metabolism. Our study also reveals that warfarin is a potential repurposing drug in cancer therapy, particularly for tumors with high levels of VKORC1L1 expression.

Genetic Factors Influencing Warfarin Dose in Han Chinese Population: A Systematic Review and Meta-Analysis of Cohort Studies.

OBJECTIVE: To investigate the association of single nucleotide polymorphisms (SNPs) of various genes known to influence mean daily warfarin dose (MDWD) in the Han Chinese population. METHODS: The study is a systematic review and meta-analysis. Selected studies retrieved by searching Pubmed, Embase (Ovid), Medline, CNKI, Wanfang data, and SinoMed (from their inception to 31 August 2022) for the cohort studies assessing genetic variations that may possibly influence MDWD in Chinese patients were included. RESULT: A total of 46 studies including a total of 10,102 Han Chinese adult patients were finally included in the meta-analysis. The impact of 20 single nucleotide polymorphisms (SNPs) in 8 genes on MDWD was analyzed. The significant impact of some of these SNPs on MDWD requirements was demonstrated. Patients with CYP4F2 rs2108622 TT, EPHX1 rs2260863 GC, or NQO1 rs1800566 TT genotype required more than 10% higher MDWD. Furthermore, patients with ABCB1 rs2032582 GT or GG, or CALU rs2290228 TT genotype required more than 10% lower MDWD. Subgroup analysis showed that patients with EPHX1 rs2260863 GC genotype required 7% lower MDWD after heart valve replacement (HVR). CONCLUSION: This is the first systematic review and meta-analysis assessing the association between single nucleotide polymorphisms (SNPs) of various genes known to influence MDWD besides CYP2C9 and VKORC1 in the Han Chinese population. CYP4F2 (rs2108622), GGCX (rs12714145), EPHX1 (rs2292566 and rs2260863), ABCB1 (rs2032582), NQO1 (rs1800566), and CALU (rs2290228) SNPs might be moderate factors affecting MDWD requirements. REGISTERED INFORMATION: PROSPERO International Prospective Register of Systematic Reviews (CRD42022355130).

Development of an electrochemical DNA-based biosensor for the detection of the cardiovascular pharmacogenetic-altering SNP CYP2C9*3.

Cardiovascular diseases are among the major causes of mortality and morbidity. Warfarin is often prescribed for these disorders, an anticoagulant with inter and intra-dosage variability dose required to achieve the target international normalized ratio. Warfarin presents a narrow therapeutic index, and due to its variability, it can often be associated with the risk of hemorrhage, or in other patients, thromboembolism. Single-nucleotide polymorphisms are included in the causes that contribute to this variability. The Cytochrome P450 (CYP) 2C9*3 genetic polymorphism modifies its enzymatic activity, and hence warfarin's plasmatic concentration. Thus, the need for a selective, rapid, low-cost, and real-time detection device is crucial before prescribing warfarin. In this work, a disposable electrochemical DNA-based biosensor capable of detecting CYP2C9*3 polymorphism was developed. By analyzing genomic databases, two specific 78 base pairs DNA probes; one with the wild-type adenine (Target-A) and another with the cytosine (Target-C) single-nucleotide genetic variation were designed. The biosensor implied the immobilization on screen-printed gold electrodes of a self-assembled monolayer composed by mercaptohexanol and a linear CYP2C9*3 DNA-capture probe. To improve the selectivity and avoid secondary structures a sandwich format of the CYP2C9*3 allele was designed using complementary fluorescein isothiocyanate-labeled signaling DNA probe and enzymatic amplification of the electrochemical signal. Chronoamperometric measurements were performed at a range of 0.015-1.00 nM for both DNA targets achieving limit of detection of 42 p.m. The developed DNA-based biosensor was able to discriminate between the two synthetic target DNA targets, as well as the targeted denatured genomic DNA, extracted from volunteers genotyped as non-variant homozygous (A/A) and heterozygous (A/C) of the CYP2C9*3 polymorphism.