Pharmacogenomics
<em>Influence of CYP2B6 Pharmacogenetics on Stereoselective Inhibition and Induction of Bupropion Metabolism by Efavirenz in Healthy Volunteers</em>
J Pharmacol Exp Ther. 2022 Jul 7:JPET-AR-2022-001277. doi: 10.1124/jpet.122.001277. Online ahead of print.
ABSTRACT
We investigated the acute and chronic effects of efavirenz, a widely used antiretroviral drug, and CYP2B6 genotypes on the disposition of racemic and stereoisomers of bupropion (BUP) and its active metabolites, 4-hydroxyBUP, threohydroBUP and erythrohydroBUP. The primary objective of this study was to test how multiple processes unique to the efavirenz-CYP2B6 genotype interaction influence the extent of efavirenz-mediated drug-drug interaction (DDI) with the CYP2B6 probe substrate BUP. In a three-phase, sequential, open-label study, healthy volunteers (N=53) were administered a single 100 mg oral dose of BUP alone (control phase), with a single 600 mg oral efavirenz dose (inhibition phase), and after 17-days pretreatment with efavirenz (600 mg/day) (induction phase). Compared to the control phase, we show for the first time that efavirenz significantly decreases and chronically increases the exposure of hydroxyBUP and its diastereomers, respectively, and these interactions were CYP2B6 genotype dependent. Chronic efavirenz enhances the elimination of racemic BUP and its enantiomers as well as of threo- and erythro-hydroBUP and their diastereomers, suggesting additional novel mechanisms underlying efavirenz interaction with BUP. The effects of efavirenz and genotypes were nonstereospecific. In conclusion, acute and chronic administration of efavirenz inhibits and induces CYP2B6 activity. Efavirenz-BUP interaction is complex involving time- and CYP2B6 genotype-dependent inhibition and induction of primary and secondary metabolic pathways. Our findings highlight important implications to the safety and efficacy of BUP, study design considerations for future efavirenz interactions, and individualized drug therapy based on CYP2B6 genotypes. Significance Statement The effects of acute and chronic doses of efavirenz on the disposition of racemic and stereoisomers of BUP and its active metabolites were investigated in healthy volunteers. Efavirenz causes an acute inhibition, but chronic induction of CYP2B6 in a genotype dependent manner. Chronic efavirenz induces BUP reduction and the elimination of BUP active metabolites. Efavirenz's effects were non-stereospecific. These data reveal novel mechanisms underlying efavirenz DDI with BUP and provide important insights into time- and CYP2B6 genotype dependent DDIs.
PMID:35798386 | DOI:10.1124/jpet.122.001277
PharmVar GeneFocus: SLCO1B1
Clin Pharmacol Ther. 2022 Jul 7. doi: 10.1002/cpt.2705. Online ahead of print.
ABSTRACT
The Pharmacogene Variation Consortium (PharmVar) is now providing star (*) allele nomenclature for the highly polymorphic human SLCO1B1 gene encoding the organic anion transporting polypeptide 1B1 (OATP1B1) drug transporter. Genetic variation within the SLCO1B1 gene locus impacts drug transport, which can lead to altered pharmacokinetic profiles of several commonly prescribed drugs. Variable OATP1B1 function is of particular importance regarding hepatic uptake of statins and the risk of statin-associated musculoskeletal symptoms (SAMS). To introduce this important drug transporter gene into the PharmVar database and serve as a unified reference of haplotype variation moving forward, an international group of gene experts has performed an extensive review of all published SLCO1B1 star alleles. Previously published star alleles were self-assigned by authors and only loosely followed the star nomenclature system which was first developed for Cytochrome P450 genes. This nomenclature system has been standardized by PharmVar and is now applied to other important pharmacogenes such as SLCO1B1. In addition, data from the 1000 Genomes Project and investigator-submitted data were utilized to confirm existing haplotypes, fill knowledge gaps and/or define novel star alleles. The PharmVar-developed SLCO1B1 nomenclature has been incorporated by the Clinical Pharmacogenetics Implementation Consortium (CPIC) 2022 guideline on statin-associated musculoskeletal symptoms.
PMID:35797228 | DOI:10.1002/cpt.2705
Systematic review of mitochondrial genetic variation in attention-deficit/hyperactivity disorder
Eur Child Adolesc Psychiatry. 2022 Jul 7. doi: 10.1007/s00787-022-02030-6. Online ahead of print.
ABSTRACT
The global prevalence of attention-deficit/hyperactivity disorder (ADHD) is estimated to be between 6% and 7% in children worldwide. The pathophysiology of this heterogeneous neurodevelopmental disorder remains unknown. Mitochondrial dysfunction has been proposed as a possible contributing factor to the etiology of ADHD. There is limited literature available to help our understanding of this hypothesis, and thus we conducted a systematic review of the number and quality of studies pertaining to mitochondrial genetic alterations in ADHD. A systematic search was conducted in the relevant databases Medline (PubMed) and Embase up to March 2021. Inclusion criteria included randomized control trials, cross-sectional studies, and case-control studies. This search resulted in a total of 507 articles that emerged from the search criteria. Of these results, 10 primary research articles were selected for in depth review based on the inclusion and exclusion criteria. These studies all reported on mitochondrial genetic variation in ADHD cases such as increased copy number, single-nucleotide polymorphisms, and haplogroup associations. This initial review of the experimental literature suggests mitochondrial genetic variation, in both the mitochondrial DNA and nuclear-encoded mitochondrial genes, may indeed contribute to ADHD pathophysiology. The studies reviewed here provide promising evidence for future research to further examine the mitochondrial genetics contributing to ADHD pathophysiology. We suggest that expansion of investigations into mitochondrial mechanisms may have potential to inform new treatment options for ADHD.
PMID:35796884 | DOI:10.1007/s00787-022-02030-6
Current and future physiologically based pharmacokinetic (PBPK) modeling approaches to optimize pharmacotherapy in preterm neonates
Expert Opin Drug Metab Toxicol. 2022 Jul 7. doi: 10.1080/17425255.2022.2099836. Online ahead of print.
ABSTRACT
INTRODUCTION: There is a need for structured approaches to inform on pharmacotherapy in preterm neonates. With their proven track record up to regulatory acceptance, physiologically based pharmacokinetic (PBPK) modeling and simulation provide such a structured approach, and hold the promise to support drug development in preterm neonates.
AREAS COVERED: Compared to the general and pediatric use of PBPK modeling, its use to inform pharmacotherapy in preterms is limited. Using a systematic search (PBPK + preterm), we retained 25 records (20 research papers, 2 letters, 3 abstracts). We subsequently collated the published information on PBPK software packages (PK-Sim®, Simcyp®), and their applications and optimization efforts in preterm neonates. It is encouraging that these applications cover a broad range of scenarios (pharmacokinetic-dynamic analyses, drug-drug interactions, developmental pharmacogenetics, lactation related exposure) and compounds (small molecules, proteins). Furthermore, specific compartments (cerebrospinal fluid, tissue) or (patho)physiologic processes (cardiac output, biliary excretion, first pass metabolism) are considered.
EXPERT OPINION: Knowledge gaps exist, giving rise to various levels of model uncertainty in PBPK applications in preterm neonates. To improve this setting, we need cross talk between clinicians and modelers to generate and integrate knowledge (PK datasets, system knowledge, maturational physiology and pathophysiology) to further refine PBPK models.
PMID:35796504 | DOI:10.1080/17425255.2022.2099836
The Impact of Pharmacogenetics on Pharmacokinetics and Pharmacodynamics in Neonates and Infants: A Systematic Review
Pharmgenomics Pers Med. 2022 Jun 30;15:675-696. doi: 10.2147/PGPM.S350205. eCollection 2022.
ABSTRACT
In neonates, pharmacogenetics has an additional layer of complexity. This is because in addition to genetic variability in genes that code for proteins relevant to clinical pharmacology, there are rapidly maturational changes in these proteins. Consequently, pharmacotherapy in neonates has unique challenges. To provide a contemporary overview on pharmacogenetics in neonates, we conducted a systematic review to identify, describe and quantify the impact of pharmacogenetics on pharmacokinetics and -dynamics in neonates and infants (PROSPERO, CRD42022302029). The search was performed in Medline, Embase, Web of Science and Cochrane, and was extended by a PubMed search on the 'top 100 Medicines' (medicine + newborn/infant + pharmacogen*) prescribed to neonates. Following study selection (including data in infants, PGx related) and quality assessment (Newcastle-Ottawa scale, Joanna Briggs Institute tool), 55/789 records were retained. Retained records relate to metabolizing enzymes involved in phase I [cytochrome P450 (CYP1A2, CYP2A6, CYP2B6, CYP2C8/C9/C18, CYP2C19, CYP2D6, CYP3A5, CYP2E1)], phase II [glutathione-S-transferases, N-acetyl transferases, UDP-glucuronosyl-transferase], transporters [ATP-binding cassette transporters, organic cation transporters], or receptor/post-receptor mechanisms [opioid related receptor and post-receptor mechanisms, tumor necrosis factor, mitogen-activated protein kinase 8, vitamin binding protein diplotypes, corticotrophin-releasing hormone receptor-1, nuclear receptor subfamily-1, vitamin K epoxide reductase complex-1, and angiotensin converting enzyme variants]. Based on the available overview, we conclude that the majority of reported pharmacogenetic studies explore and extrapolate observations already described in older populations. Researchers commonly try to quantify the impact of these polymorphisms in small datasets of neonates or infants. In a next step, pharmacogenetic studies in neonatal life should go beyond confirmation of these associations and explore the impact of pharmacogenetics as a covariate limited to maturation of neonatal life (ie, fetal malformations, breastfeeding or clinical syndromes). The challenge is to identify the specific factors, genetic and non-genetic, that contribute to the best benefit/risk balance.
PMID:35795337 | PMC:PMC9252316 | DOI:10.2147/PGPM.S350205
Gut microbiota composition in colorectal cancer patients is genetically regulated
Sci Rep. 2022 Jul 6;12(1):11424. doi: 10.1038/s41598-022-15230-6.
ABSTRACT
The risk of colorectal cancer (CRC) depends on environmental and genetic factors. Among environmental factors, an imbalance in the gut microbiota can increase CRC risk. Also, microbiota is influenced by host genetics. However, it is not known if germline variants influence CRC development by modulating microbiota composition. We investigated germline variants associated with the abundance of bacterial populations in the normal (non-involved) colorectal mucosa of 93 CRC patients and evaluated their possible role in disease. Using a multivariable linear regression, we assessed the association between germline variants identified by genome wide genotyping and bacteria abundances determined by 16S rRNA gene sequencing. We identified 37 germline variants associated with the abundance of the genera Bacteroides, Ruminococcus, Akkermansia, Faecalibacterium and Gemmiger and with alpha diversity. These variants are correlated with the expression of 58 genes involved in inflammatory responses, cell adhesion, apoptosis and barrier integrity. Genes and bacteria appear to be involved in the same processes. In fact, expression of the pro-inflammatory genes GAL, GSDMD and LY6H was correlated with the abundance of Bacteroides, which has pro-inflammatory properties; abundance of the anti-inflammatory genus Faecalibacterium correlated with expression of KAZN, with barrier-enhancing functions. Both the microbiota composition and local inflammation are regulated, at least partially, by the same germline variants. These variants may regulate the microenvironment in which bacteria grow and predispose to the development of cancer. Identification of these variants is the first step to identifying higher-risk individuals and proposing tailored preventive treatments that increase beneficial bacterial populations.
PMID:35794137 | DOI:10.1038/s41598-022-15230-6
Influence of glutathione-S-transferase A1*B allele on the metabolism of the aromatase inhibitor, exemestane, in human liver cytosols and in patients treated with exemestane
J Pharmacol Exp Ther. 2022 Jul 6:JPET-AR-2022-001232. doi: 10.1124/jpet.122.001232. Online ahead of print.
ABSTRACT
Exemestane (EXE) is used to treat post-menopausal women diagnosed with estrogen receptor positive (ER+) breast cancer. A major mode of metabolism of EXE and its active metabolite, 17β-dihydroexemestane (17β-DHE), is via glutathionylation by glutathione-S-transferase (GST) enzymes. The goal of the present study was to investigate the effects of genetic variation in EXE-metabolizing GST enzymes on overall EXE metabolism. Ex vivo assays examining human liver cytosols (HLC) from 75 subjects revealed the GSTA1 *B/*B genotype was associated with significant decreases in EXE-GS (P=0.034) and DHE-GS (P=0.014) formation. In the plasma of 68 ER+ breast cancer patients treated with EXE, the GSTA1 *B*B genotype was associated with significant decreases in both EXE-cys (29%, P=0.0056) and DHE-cys (34%, P=0.032) as compared to patients with the GSTA1*A*A genotype, with significant decreases in EXE-cys (Ptrend=0.0067) and DHE-cys (Ptrend=0.028) observed in patients with increasing numbers of the GSTA1*B allele. A near-significant (Ptrend=0.060) trend was also observed for urinary EXE-cys levels from the same patients. In contrast, plasma and urinary DHE-Gluc levels were significantly increased (36%, P=0.00097 and 52%, P=0.0089; respectively) in patients with the GSTA1 *B*B genotype. No significant correlations were observed between the GSTM1 null genotype and EXE metabolite levels. These data suggest that the GSTA1*B allele is associated with interindividual differences in EXE metabolism and may play a role in interindividual variability in overall response to EXE. Significance Statement The present study is the first comprehensive pharmacogenomic investigation examining the role of genetic variability in GST enzymes on exemestane metabolism. The GSTA1 *B*B genotype was found to contribute to interindividual differences in the metabolism of EXE both ex vivo and in clinical samples from patients taking EXE for the treatment of ER+ breast cancer. GSTA1 is a major hepatic phase II metabolizing enzyme in EXE metabolism, the GSTA1*B allele may be an important biomarker for treatment outcomes and toxicities.
PMID:35793834 | DOI:10.1124/jpet.122.001232
Challenges Related to the Use of Next-Generation Sequencing for the Optimization of Drug Therapy
Handb Exp Pharmacol. 2022 Jul 7. doi: 10.1007/164_2022_596. Online ahead of print.
ABSTRACT
Over the last decade, next-generation sequencing (NGS) methods have become increasingly used in various areas of human genomics. In routine clinical care, their use is already implemented in oncology to profile the mutational landscape of a tumor, as well as in rare disease diagnostics. However, its utilization in pharmacogenomics is largely lacking behind. Recent population-scale genome data has revealed that human pharmacogenes carry a plethora of rare genetic variations that are not interrogated by conventional array-based profiling methods and it is estimated that these variants could explain around 30% of the genetically encoded functional pharmacogenetic variability.To interpret the impact of such variants on drug response a multitude of computational tools have been developed, but, while there have been major advancements, it remains to be shown whether their accuracy is sufficient to improve personalized pharmacogenetic recommendations in robust trials. In addition, conventional short-read sequencing methods face difficulties in the interrogation of complex pharmacogenes and high NGS test costs require stringent evaluations of cost-effectiveness to decide about reimbursement by national healthcare programs. Here, we illustrate current challenges and discuss future directions toward the clinical implementation of NGS to inform genotype-guided decision-making.
PMID:35792943 | DOI:10.1007/164_2022_596
Effect of cytochrome P450 inhibition on toxicity of diclofenac in chickens: Unravelling toxicity in Gyps vultures
Onderstepoort J Vet Res. 2022 Jun 14;89(1):e1-e8. doi: 10.4102/ojvr.v89i1.1978.
ABSTRACT
Diclofenac was responsible for the decimation of Gyps vulture species on the Indian subcontinent during the 1980s and 1990s. Gyps vultures are extremely sensitive (the lethal dose 50 [LD50] ~ 0.1 mg/kg - 0.2 mg/kg), with toxicity appearing to be linked to metabolic deficiency, demonstrated by the long T1/2 (~12 h - 17 h). This is in striking comparison to the domestic chicken (Gallus gallus domesticus), in which the LD50 is ~10 mg/kg and the T1/2 is ~1 h. The phase 1 cytochrome P450 (CYP) 2C subfamily has been cited as a possible reason for metabolic deficiency. The aim of this study was to determine if CYP2C9 homolog pharmacogenomic differences amongst avian species is driving diclofenac toxicity in Gyps vultures. We exposed each of 10 CYP-inhibited test group chickens to a unique dose of diclofenac (as per the Organisation for Economic Co-operation and Development [OECD] toxicity testing guidelines) and compared the toxicity and pharmacokinetic results to control group birds that received no CYP inhibitor. Although no differences were noted in the LD50 values for each group (11.92 mg/kg in the CYP-inhibited test group and 11.58 mg/kg in the control group), the pharmacokinetic profile of the test group was suggestive of partial inhibition of CYP metabolism. Evaluation of the metabolite peaks produced also suggested partial metabolic inhibition in test group birds, as they produced lower amounts of metabolites for one of the three peaks demonstrated and had higher diclofenac exposure. This pilot study supports the hypothesis that CYP metabolism is varied amongst bird species and may explain the higher resilience to diclofenac in the chicken versus vultures.
PMID:35792606 | DOI:10.4102/ojvr.v89i1.1978
Identify Multiple Gene-Drug Common Modules Via Constrained Graph Matching
IEEE J Biomed Health Inform. 2022 Jul 5;PP. doi: 10.1109/JBHI.2022.3188503. Online ahead of print.
ABSTRACT
Identifying gene-drug interactions is vital to understanding biological mechanisms and achieving precise drug repurposing. High-throughput technologies produce a large amount of pharmacological and genomic data, providing an opportunity to explore the associations between oncogenic genes and therapeutic drugs. However, most studies only focus on "one-to-one" or "one-to-many" interactions, ignoring the multivariate patterns between genes and drugs. In this article, a high-order graph matching model with hypergraph constraints is proposed to discover the gene-drug common regulatory modules. Moreover, the prior knowledge is formulated into hypergraph constraints to reveal their multiple correspondences, penalizing the tensor matching process. The experimental results on the synthetic data demonstrate the proposed model is robust to noise contamination and outlier corruption, achieving a better performance than four state-of-the-art methods. We then evaluate the statistical power of our proposed method on the pharmacogenomics data. Our identified gene-drug common modules not only show significantly enriched pathways associated with cancer but also manifest the highly close gene-drug interactions.
PMID:35788454 | DOI:10.1109/JBHI.2022.3188503
JAK Inhibition as a New Treatment Strategy for Patients with COVID-19
Biochem Pharmacol. 2022 Jul 1:115162. doi: 10.1016/j.bcp.2022.115162. Online ahead of print.
ABSTRACT
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic continues to spread globally. The rapid dispersion of coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 drives an urgent need for effective treatments, especially for patients who develop severe pneumonia. The excessive and uncontrolled release of pro-inflammatory cytokines has proved to be an essential factor in the rapidity of disease progression, and some cytokines are significantly associated with adverse outcomes. Most of the upregulated cytokines signal through the Janus kinase-signal transducer and activator of transcription (JAK/STAT) pathway. Therefore, blocking the exaggerated release of cytokines, including IL-2, IL-6, TNF-α, and IFNα/β/γ, by inhibiting JAK/STAT signaling will, presumably, offer favorable pharmacodynamics and present an attractive prospect. JAK inhibitors (JAKi) can also inhibit members of the numb-associated kinase (NAK) family, including AP2-associated kinase 1 (AAK1) and cyclin G-associated kinase (GAK), which regulate the angiotensin-converting enzyme 2 (ACE-2) transmembrane protein and are involved in host viral endocytosis. According to the data released from current clinical trials, JAKi treatment can effectively control the dysregulated cytokine storm and improve clinical outcomes regarding mortality, ICU admission, and discharge. There are still some concerns surrounding thromboembolic events, opportunistic infection such as herpes zoster virus reactivation, and repression of the host's type-I IFN-dependent immune repair for both viral and bacterial infection. However, the current JAKi clinical trials of COVID-19 raised no new safety concerns except a slightly increased risk of herpes virus infection. In the updated WHO guideline, Baricitinb is strongly recommended as an alternative to IL-6 receptor blockers, particularly in combination with corticosteroids, in patients with severe or critical COVID-19. Future studies will explore the application of JAKi to COVID-19 treatment in greater detail, such as the optimal timing and course of JAKi treatment, individualized medication strategies based on pharmacogenomics, and the effect of combined medications.
PMID:35787993 | DOI:10.1016/j.bcp.2022.115162
Integrated Analysis of Expression Profile and Potential Pathogenic Mechanism of Temporal Lobe Epilepsy With Hippocampal Sclerosis
Front Neurosci. 2022 Jun 16;16:892022. doi: 10.3389/fnins.2022.892022. eCollection 2022.
ABSTRACT
OBJECTIVE: To investigate the potential pathogenic mechanism of temporal lobe epilepsy with hippocampal sclerosis (TLE+HS) by analyzing the expression profiles of microRNA/ mRNA/ lncRNA/ DNA methylation in brain tissues.
METHODS: Brain tissues of six patients with TLE+HS and nine of normal temporal or parietal cortices (NTP) of patients undergoing internal decompression for traumatic brain injury (TBI) were collected. The total RNA was dephosphorylated, labeled, and hybridized to the Agilent Human miRNA Microarray, Release 19.0, 8 × 60K. The cDNA was labeled and hybridized to the Agilent LncRNA+mRNA Human Gene Expression Microarray V3.0,4 × 180K. For methylation detection, the DNA was labeled and hybridized to the Illumina 450K Infinium Methylation BeadChip. The raw data was extracted from hybridized images using Agilent Feature Extraction, and quantile normalization was performed using the Agilent GeneSpring. P-value < 0.05 and absolute fold change >2 were considered the threshold of differential expression data. Data analyses were performed using R and Bioconductor. BrainSpan database was used to screen for signatures that were not differentially expressed in normal human hippocampus and cortex (data from BrainSpan), but differentially expressed in TLE+HS' hippocampus and NTP' cortex (data from our cohort). The strategy "Guilt by association" was used to predict the prospective roles of each important hub mRNA, miRNA, or lncRNA.
RESULTS: A significantly negative correlation (r < -0.5) was found between 116 pairs of microRNA/mRNA, differentially expressed in six patients with TLE+HS and nine of NTP. We examined this regulation network's intersection with target gene prediction results and built a lncRNA-microRNA-Gene regulatory network with structural, and functional significance. Meanwhile, we found that the disorder of FGFR3, hsa-miR-486-5p, and lnc-KCNH5-1 plays a key vital role in developing TLE+HS.
PMID:35784838 | PMC:PMC9243442 | DOI:10.3389/fnins.2022.892022
Importance of Rare <em>DPYD</em> Genetic Polymorphisms for 5-Fluorouracil Therapy in the Japanese Population
Front Pharmacol. 2022 Jun 15;13:930470. doi: 10.3389/fphar.2022.930470. eCollection 2022.
ABSTRACT
Dihydropyrimidine dehydrogenase (DPD), encoded by the DPYD gene, is the rate-limiting enzyme in 5-fluorouracil (5-FU) degradation. In Caucasians, four DPYD risk variants are recognized to be responsible for interindividual variations in the development of 5-FU toxicity. However, these risk variants have not been identified in Asian populations. Recently, 41 DPYD allelic variants, including 15 novel single nucleotide variants, were identified in 3,554 Japanese individuals by analyzing their whole-genome sequences; however, the effects of these variants on DPD enzymatic activity remain unknown. In the present study, an in vitro analysis was performed on 41 DPD allelic variants and three DPD risk variants to elucidate the changes in enzymatic activity. Wild-type and 44 DPD-variant proteins were heterologously expressed in 293FT cells. DPD expression levels and dimerization of DPD were determined by immunoblotting after SDS-PAGE and blue native PAGE, respectively. The enzymatic activity of DPD was evaluated by quantification of dihydro-5-FU, a metabolite of 5-FU, using high-performance liquid chromatography-tandem mass spectrometry. Moreover, we used 3D simulation modeling to analyze the effect of amino acid substitutions on the conformation of DPD. Among the 41 DPD variants, seven exhibited drastically decreased intrinsic clearance (CL int ) compared to the wild-type protein. Moreover, R353C and G926V exhibited no enzymatic activity, and the band patterns observed in the immunoblots after blue native PAGE indicated that DPD dimerization is required for its enzymatic activity. Our data suggest that these variants may contribute to the significant inter-individual variability observed in the pharmacokinetics and pharmacodynamics of 5-FU. In our study, nine DPD variants exhibited drastically decreased or no enzymatic activity due to dimerization inhibition or conformational changes in each domain. Especially, the rare DPYD variants, although at very low frequencies, may serve as important pharmacogenomic markers associated with the severe 5-FU toxicity in Japanese population.
PMID:35784703 | PMC:PMC9242541 | DOI:10.3389/fphar.2022.930470
Why We Need to Take a Closer Look at Genetic Contributions to CYP3A Activity
Front Pharmacol. 2022 Jun 16;13:912618. doi: 10.3389/fphar.2022.912618. eCollection 2022.
ABSTRACT
Cytochrome P450 3A (CYP3A) subfamily enzymes are involved in the metabolism of 40% of drugs in clinical use. Twin studies have indicated that 66% of the variability in CYP3A4 activity is hereditary. Yet, the complexity of the CYP3A locus and the lack of distinct drug metabolizer phenotypes has limited the identification and clinical application of CYP3A genetic variants compared to other Cytochrome P450 enzymes. In recent years evidence has emerged indicating that a substantial part of the missing heritability is caused by low frequency genetic variation. In this review, we outline the current pharmacogenomics knowledge of CYP3A activity and discuss potential future directions to improve our genetic knowledge and ability to explain CYP3A variability.
PMID:35784699 | PMC:PMC9243486 | DOI:10.3389/fphar.2022.912618
Pharmacogenetics: A Precision Medicine Approach to Combatting the Opioid Epidemic
J Am Coll Clin Pharm. 2022 Feb;5(2):239-250. doi: 10.1002/jac5.1582. Epub 2021 Dec 19.
ABSTRACT
Ineffective pain control is the most commonly cited reason for misuse of prescription opioids and is influenced by genetics. In particular, the gene encoding the CYP2D6 enzyme, which metabolizes some of the most commonly prescribed opioids (e.g., tramadol, hydrocodone) to their more potent forms, is highly polymorphic and can lead to reduced concentrations of the active metabolites and decreased opioid effectiveness. Consideration of the CYP2D6 genotype may allow for predicting opioid response and identifying patients who are likely to respond well to lower potency opioids as well as those who may derive greater pain relief from non-opioid analgesics versus certain opioids. There is emerging evidence that a CYP2D6-guided approach to pain management improves pain control and reduces opioid consumption and thus may be a promising means for combating opioid misuse. Clinical practice guidelines are available for select opioids and other analgesics to support medication and dose selection based on pharmacogenetic data. This article describes the evidence supporting genotype-guided pain management as a means of improving pain control and reducing opioid misuse and clinical recommendations for genotype-guided analgesic prescribing. In addition, a "how to" guide using patient case examples is provided to demystify the process for implementing pharmacogenetics-guided pain management in order to optimize analgesia and minimize adverse effects. Optimizing pain management through genotype-guided approaches may ultimately provide safer and more effective therapy for pain control while decreasing the risk for opioid misuse.
PMID:35784584 | PMC:PMC9248444 | DOI:10.1002/jac5.1582
Non-effectiveness of Ivermectin on Inpatients and Outpatients With COVID-19; Results of Two Randomized, Double-Blinded, Placebo-Controlled Clinical Trials
Front Med (Lausanne). 2022 Jun 16;9:919708. doi: 10.3389/fmed.2022.919708. eCollection 2022.
ABSTRACT
BACKGROUND: Ivermectin which was widely considered as a potential treatment for COVID-19, showed uncertain clinical benefit in many clinical trials. Performing large-scale clinical trials to evaluate the effectiveness of this drug in the midst of the pandemic, while difficult, has been urgently needed.
METHODS: We performed two large multicenter randomized, double-blind, placebo-controlled clinical trials evaluating the effectiveness of ivermectin in treating inpatients and outpatients with COVID-19 infection. The intervention group received ivermectin, 0.4mg/kg of body weight per day for 3 days. In the control group, placebo tablets were used for 3 days.
RESULTS: Data for 609 inpatients and 549 outpatients were analyzed. In hospitalized patients, complete recovery was significantly higher in the ivermectin group (37%) compared to placebo group (28%; RR, 1.32 [95% CI, 1.04-1.66]; p-value = 0.02). On the other hand, the length of hospital stay was significantly longer in the ivermectin group with a mean of 7.98 ± 4.4 days compared to the placebo receiving group with a mean of 7.16 ± 3.2 days (RR, 0.80 [95% CI, 0.15-1.45]; p-value = 0.02). In outpatients, the mean duration of fever was significantly shorter (2.02 ± 0.11 days) in the ivermectin group versus (2.41 ± 0.13 days) placebo group with p value = 0.020. On the day seventh of treatment, fever (p-value = 0.040), cough (p-value = 0.019), and weakness (p-value = 0.002) were significantly higher in the placebo group compared to the ivermectin group. Among all outpatients, 7% in ivermectin group and 5% in placebo group needed to be hospitalized (RR, 1.36 [95% CI, 0.65-2.84]; p-value = 0.41). Also, the result of RT-PCR on day five after treatment was negative for 26% of patients in the ivermectin group versus 32% in the placebo group (RR, 0.81 [95% CI, 0.60-1.09]; p-value = 0.16).
CONCLUSION: Our data showed, ivermectin, compared with placebo, did not have a significant potential effect on clinical improvement, reduced admission in ICU, need for invasive ventilation, and death in hospitalized patients; likewise, no evidence was found to support the prescription of ivermectin on recovery, reduced hospitalization and increased negative RT-PCR assay for SARS-CoV-2 5 days after treatment in outpatients. Our findings do not support the use of ivermectin to treat mild to severe forms of COVID-19.
CLINICAL TRIAL REGISTRATION: www.irct.ir IRCT20111224008507N5 and IRCT20111224008507N4.
PMID:35783616 | PMC:PMC9244711 | DOI:10.3389/fmed.2022.919708
New modular platform based on multi-adjuvanted amphiphilic chitosan nanoparticles for efficient lipopeptide vaccine delivery against group A streptococcus
Asian J Pharm Sci. 2022 May;17(3):435-446. doi: 10.1016/j.ajps.2022.04.002. Epub 2022 Apr 30.
ABSTRACT
An effective vaccine against group A streptococcus (GAS) is highly desirable for definitive control of GAS infections. In the present study, two variants of amphiphilic chitosan nanoparticles-based GAS vaccines were developed. The vaccines were primarily composed of encapsulated KLH protein (a source of T helper cell epitopes) and lipidated M-protein derived B cell peptide epitope (lipoJ14) within the amphiphilic structure of nanoparticles. The only difference between them was one of the nanoparticles vaccines received additional surface coating with poly (I:C). The formulated vaccines exhibited nanosized particles within the range of 220-240 nm. Cellular uptake study showed that nanoparticles vaccine without additional poly (I:C) coating has greater uptake by dendritic cells and macrophages compared to nanoparticles vaccine that was functionalized with poly (I:C). Both vaccines were found to be safe in mice and showed negligible cytotoxicity against HEK293 cells. Upon immunization in mice, both nanoparticle vaccines produced high antigen-specific antibodies titres that were regulated by a balanced Th1 and Th2 response compared to physical mixture. These antibodies elicited high opsonic activity against the tested GAS strains. Overall, our data demonstrated that amphiphilic chitosan nanoparticles platform induced a potent immune response even without additional inclusion of poly (I:C).
PMID:35782331 | PMC:PMC9237632 | DOI:10.1016/j.ajps.2022.04.002
The clinically relevant CYP2C8*3 and CYP2C9*2 haplotype is inherited from Neandertals
Pharmacogenomics J. 2022 Jul 2. doi: 10.1038/s41397-022-00284-6. Online ahead of print.
ABSTRACT
Genetic variation in genes encoding cytochrome P450 enzymes influences the metabolism of drugs and endogenous compounds. The locus containing the cytochrome genes CYP2C8 and CYP2C9 on chromosome 10 exhibits linkage disequilibrium between the CYP2C8*3 and CYP2C9*2 alleles, forming a haplotype of ~300 kilobases. This haplotype is associated with altered metabolism of several drugs, most notably reduced metabolism of warfarin and phenytoin, leading to toxicity at otherwise therapeutic doses. Here we show that this haplotype is inherited from Neandertals.
PMID:35780191 | DOI:10.1038/s41397-022-00284-6
Gut microbiota and host Cyp450s co-contribute to pharmacokinetic variability in mice with non-alcoholic steatohepatitis: Effects vary from drug to drug
J Adv Res. 2022 Jul;39:319-332. doi: 10.1016/j.jare.2021.10.004. Epub 2021 Oct 18.
ABSTRACT
INTRODUCTION: Pharmacokinetic variability in disease state is common in clinical practice, but its underlying mechanism remains unclear. Recently, gut microbiota has been considered to be pharmacokinetically equivalent to the host liver. Although some studies have explored the roles of gut microbiota and host Cyp450s in drug pharmacokinetics, few have explored their effects on pharmacokinetic variability, especially in disease states.
OBJECTIVES: In this study, we aim to investigate the effects of gut microbiota and host Cyp450s on pharmacokinetic variability in mice with non-alcoholic steatohepatitis (NASH), and to elucidate the contribution of gut microbiota and host Cyp450s to pharmacokinetic variability in this setting.
METHODS: The pharmacokinetic variability of mice with NASH was explored under intragastric and intravenous administrations of a cocktail mixture of omeprazole, phenacetin, midazolam, tolbutamide, chlorzoxazone, and metoprolol, after which the results were compared with those obtained from the control group. Thereafter, the pharmacokinetic variabilities of all drugs and their relations to the changes in gut microbiota and host Cyp450s were compared and analyzed.
RESULTS: The exposures of all drugs, except metoprolol, significantly increased in the NASH group under intragastric administration. However, no significant increase in the exposure of all drugs, except tolbutamide, was observed in the NASH group under intravenous administration. The pharmacokinetic variabilities of phenacetin, midazolam, omeprazole, and chlorzoxazone were mainly associated with decreased elimination activity in the gut microbiota. By contrast, the pharmacokinetic variability of tolbutamide was mainly related to the change in the host Cyp2c65. Notably, gut microbiota and host Cyp450s exerted minimal effects on the pharmacokinetic variability of metoprolol.
CONCLUSION: Gut microbiota and host Cyp450s co-contribute to the pharmacokinetic variability in mice with NASH, and the degree of contribution varies from drug to drug. The present findings provide new insights into the explanation of pharmacokinetic variability in disease states.
PMID:35777915 | DOI:10.1016/j.jare.2021.10.004
Customized 3D-printed hollow capsular device filled with norfloxacin-loaded micropellets for controlled-release delivery
Drug Deliv Transl Res. 2022 Jul 1. doi: 10.1007/s13346-022-01198-3. Online ahead of print.
ABSTRACT
Pharmacotherapy has become more focused on the personalized treatment of patients with various diseases. This field of pharmacology and pharmacogenomics focuses on developing drug delivery systems designed to address the unique characteristics of individual patients. Three-dimensional printing technology can be used to fabricate personalized drug delivery systems with desired release properties according to patient needs. Norfloxacin (NOR)-loaded micropellets (MPs) were fabricated and filled inside a stereolithography (SLA) 3D printing technology-mediated hollow capsular device in accordance with a standard size of 09 (8.4 mm length × 2.70 mm diameter). The prepared 3D-printed hollow capsular device filled with pristine NOR and NOR-loaded MPs were characterized in terms of both in vitro and in vivo means. MPs with the particle size distribution of 1540.0 ± 26 µm showed 95.63 ± 2.0% NOR content with pellet-shaped surface morphology. The in vitro release profile showed an initial lag phase of approximately 30 min, followed by the sustained release of NOR from MPs from the 3D-printed hollow capsular device. The pharmacokinetic profile showed prolonged Tmax, AUC, and evidence of good RBA of NOR compared to pure NOR after a single oral administration in the experimental animal model. The overall results confirm the feasibility of SLA-mediated 3D printing technology for preparing customized solid oral unit dosage carriers that can be filled with pure NOR- and NOR-loaded MPs with controlled-release delivery features.
PMID:35776385 | DOI:10.1007/s13346-022-01198-3