Warfarin genetic biomarkers in VKORC1 and CYP2C9*2 genes: Advancing personalized anticoagulant therapy using electrochemical genosensors

The genetic variants of vitamin K epoxide reductase complex (VKORC1) and in the cytochrome CYP2C9*2 genes have been identified to influence the anticoagulant warfarin and influence its plasmatic levels. Therefore, the pharmacogenetic information on these genes is useful for reducing warfarin adverse reaction. This work addresses the development of disposable electrochemical genosensors able of detecting single nucleotide polymorphism (SNP) in the VKORC1 and CYP2C9*2 genes. The genosensor methodology implied the immobilization of a mixed self-assembled monolayer (SAM) linear DNA-capture probe and mercaptohexanol (MCH) onto screen-printed gold electrodes (SPGE). To improve the genosensor’s selectivity and avoid strong secondary structures, that could hinder the hybridization efficiency, a sandwich format of the DNA allele was designed using a complementary fluorescein isothiocyanate-labelled signaling DNA probe and enzymatic amplification of the electrochemical signal. The developed electrochemical genosensors were able to discriminate between the two synthetic target DNA targets in both SNPs, as well as the targeted denatured genomic DNA. Several analytical parameters, such as DNA capture probe, 6-mercaptohexanol (as spacer) and antibody concentrations, as well as hybridization temperature and incubation time, were optimized. Using the best analytical conditions calibration curves employing increasing DNA target concentractions were ploted. Polymerase Chain Reaction (PCR), will be used for further validation of the electrochemical genosensor. Disposable electrochemical genosensors capable of detecting and distinguishing between two synthetic CYP2C9*2 and VKORC1 polymorphic sequences, with high selectivity and sensibility and in various concentrations, was developed. The functionality of these analytical approaches as alternative to the conventional genotyping methodologies can relieve the public health-care systems and, hopefully, prevent ADRs related to CDV episodes.info:eu-repo/semantics/publishedVersio

Development of electrochemical genosensors for the CYPC*2 gene polymorphism detection

Pharmacogenetic studies search for heritable genetic polymorphisms that influence responses to drug therapy. Pharmacogenetics has many possible applications in cardiovascular pharmacotherapy including screening for polymorphisms to choose agents with the greatest potential for efficacy and least risk of toxicity. Pharmacogenetics also informs dose adaptations for specific drugs in patients with aberrant metabolism. Cardiovascular diseases (CVD) are considered one of the leading causes of death worldwide. To prevent cardiovascular complications and further loss of life oral anticoagulants (e.g., warfarin) are frequently prescribed to patients. Nevertheless, warfarin therapeutic agent presents narrow therapeutic windows with well-documented health risks. Some of these dose-responses are a result of specific single-nucleotide polymorphism (SNP) genetic variations present in a patient´s DNA. Among them, determined SNP in the cytochrome P4502C9 (CYP2C9), namely the CYP2C9*2, gene has been identified as dose-response altering SNP. Therefore, the need for a rapid, selective, low-cost and in real time detection device is crucial before prescribing any anticoagulant. In this work an analytical approach based on electrochemical genosensor technique is under development to create a low-cost genotyping platform able to genotype SNPs related with the therapeutic response of warfarin. Analyzing public databases, two specific 71 bp DNA probes, one with adenine (TA) and other with guanine (TG) SNP genetic variation were selected and designed. The design of this electrochemical genosensor consists of ssDNA immobilization onto gold surfaces that act as the SNPs complementary probes. The hybridization reaction is performed in a sandwich format of the complementary ssDNA, using an enzymatic scheme to amplify the electrochemical signal. The electrochemical signal was performed by using chronoamperometric technique.info:eu-repo/semantics/publishedVersio

VKORC1 gene polymorphism as cardiovascular biomarker: Detection by electrochemical genosensors

Warfarin is an anticoagulant generally used to prevent cardiovascular diseases. Since of the low therapeutic index of warfarin and frequent complications of prevention or treatment, significant differences in individual doses of warfarin are needed to achieve prophylactic and therapeutic ranges. Recent studies have been reporting that genetic variants of vitamin K epoxide reductase complex (VKORC1) influence the response to warfarin and doses [9]. So, the genetic and pharmacogenetic information of the major cardiovascular diseases plays an important role in the identification of the cardiovascular risk factors and in the diagnosis and treatment of these conditions. This work addresses the development of a disposable electrochemical genosensor able of detecting single nucleotide polymorphism (SNP) in the VKORC1 gene. Analysing public databases, two specific 52 bp DNA probes, one with adenine (TA) and another with guanine (TG) SNP genetic variation were selected and selected and designed. The genosensor methodology implied the immobilization of a mixed self-assembled monolayer (SAM) linear VKORC1 DNA-capture probe and mercaptohexanol (MCH) onto screen-printed gold electrodes (SPGE). To improve the genosensor´s selectivity and avoid strong secondary structures, that could hinder the hybridization efficiency, a sandwich format of the VKORC1 allele was designed using a complementary fluorescein isothiocyanate-labelled signaling DNA probe and enzymatic amplification of the electrochemical signal. Preliminary studies indicate that differences in the electrochemical answers were obtained depending of the hybridization reaction format. In fact, higher electrochemical intensities were measured when the hybridization reaction was performed with a complementary DNA (without SNPs). These results suggested that the sensor is able to discriminate between the complementary DNA and single base mismatch targets having a great potential for the DNA polymorphism analysis.info:eu-repo/semantics/publishedVersio

Cytochrome P450 polymorphisms with impact in cardiovascular drugs metabolisms in European populations

The cytochrome P450 (CYP) enzymes constitute a large polymorphic family that play a huge role in the metabolism of endogenous compounds and in the metabolization of 70–80% of all clinically prescribed medications. Among them, the CYP2C9, CYP2C19, CYP2D6 and CYP4F2 genes are of clinical relevance, as they are highly polymorphic and implicated in the metabolism of several drugs. These genetic polymorphisms which induce variability in CYPs expression present qualitative and quantitative differences between ethnic groups and geographic regions. This review aims to evaluate the allele frequencies, genotypic distribution and predicted CYP2C9, CYP2C19, CYP2D6 and CYP4F2 genetic variants in the European countries. Therefore, a PubMed and a Web of Science search from 1989 to 2021 on the data on the polymorphic prevalence among European countries of the CYP2C9, CYP2C19, CYP2D6 and CYP4F2 genes was performed. After excluding the duplicates, a total of 1179 studies were found. The results were structured and presented in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The present paper is an overview on the frequency CYP genetic variations, facilitating the prediction of a patient's response to medication and, consequently, enabling the selection of personalized medicineThis work was funded by the Bilateral Cooperation FCT/CAPES 2018/2019 Processo 4.4.1.00 CAPES (CAPES-FCT2017484310P 200.137.174.210). This work was also supported by UIDB/50006/2020 and UIDP/50006/2020 by the Fundação para a Ciência e a Tecnologia (FCT)/Ministério da Ciência, Tecnologia e Ensino Superior (MCTES) through national funds. M. F. Barroso thanks FCT for the FCT Investigator (ref.2020.03107.CEECIND)info:eu-repo/semantics/publishedVersio

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.info:eu-repo/semantics/publishedVersio