Pharmacology, Toxicology and Environmental Health Commons^™

Loss Of Palmitoylation Impacts The Interaction Between The Organic Anion Transporting Polypeptide (Oatp) 1b1 And Oatp1b3., Cecilia E. Villanueva, Whitney M. Nolte, Priscilla Flores-Ascencio, Bruno Hagenbuch

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The organic anion transporting polypeptide (OATP) 1B1 and OATP1B3 are hepatic transporters that mediate the uptake of numerous therapeutics like antibiotics and statins. Various post-translational modifications, eg, phosphorylation and glycosylation, have been shown to impact OATP1B1 and OATP1B3 function and localization. S-palmitoylation (also known as S-acylation or palmitoylation) is a reversible post-translational modification that adds palmitic acid (C16:0) to cysteine residues and can influence a protein's function, localization, and protein-protein interactions. In this study, we investigated and characterized palmitoylation in OATP1B1 and OATP1B3. Using site-directed mutagenesis and acyl-resin-assisted capture assays, residue Cys24 was identified as the palmitoylation site for both …

A Methotrexate Dashboard: Integrating Mtxpk.Org Into The Electronic Health Record To Facilitate Model-Informed Care For Pediatric Patients Receiving High-Dose Methotrexate., Zachary L. Taylor, Nieko Punt, Chris Jenkinson, Bill Vidonish, Jennifer Young, Maureen M. O'Brien, Laura Ramsey

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PURPOSE: The MTXPK.org webtool facilitates model-informed supportive care and glucarpidase use in patients receiving high-dose methotrexate, but its reliance on manual data entry limits workflow integration. We aimed to highlight how translational informatics can advance, automate, and enhance the usability of clinical decision support tools by embedding MTXPK.org within the electronic health record (EHR).

METHODS: A human factors study with 6 clinical providers guided iterative prototype development. MTXPK.org was rebuilt within the EHR using a 3-tier architecture with Fast Healthcare Interoperability Resources-based data retrieval, automated pharmacokinetic modeling, and interactive visualization.

RESULTS: Two rounds of prototyping with task-based evaluations and contextual …

Pharmacogenetic Hslco1b1*14-Guided Dosing Of Methotrexate In Transgenic Arthritic Mice Normalizes Exposure And Response., Felicia Gooden, Brennan D. Meier, Griffin D. Shaffer, Kim Gibson, Paul Toren, Nieko C. Punt, Sandhya Subash, Dilip K. Singh, Bhagwat Prasad, Laura Ramsey, Zachary L. Taylor

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Juvenile idiopathic arthritis (JIA) is a chronic autoimmune disease that negatively affects ~100,000 children under the age of 16 in the United States. About ~30% of these patients fail first-line drug therapy with low-dose methotrexate (MTX) due to poor tolerability or lack of efficacy. The SLCO1B1*14 allele is associated with increased MTX clearance and has been linked to reduced overall drug exposure and nonresponse to MTX in JIA patients. Herein, we describe transgenic hSLCO1B1*14 and hSLCO1B1*1 DBA1/J mSlco1b2 knock-out mice, which we used to assess arthritic response to MTX using the collagen-induced arthritis model. Mass spectrometry-based proteomics analysis revealed that …

The Clinical Pharmacogenetics Implementation Consortium's Consensus-Based Framework For Assigning Allele Function., Bailey M. Tibben, Andrea Gaedigk, Li Gong, Katrin Sangkuhl, Michelle Whirl-Carrillo, Mary V. Relling, Roseann S. Donnelly, Teri E. Klein, Kelly E. Caudle

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The Clinical Pharmacogenetics Implementation Consortium (CPIC) is dedicated to integrating pharmacogenetic testing into clinical practice by developing and disseminating peer-reviewed, evidence-based gene-drug clinical practice guidelines. A critical component of this effort is the assignment of clinical function to pharmacogene alleles, which informs the translation of genetic test results into actionable prescribing decisions. This technology review outlines the standardized procedures and framework used by CPIC to assign allele clinical functional status through the work of Pharmacogene Curation Expert Panels (PCEPs). These panels, comprising multidisciplinary experts, systematically review and evaluate evidence to assign functional status to pharmacogenetic haplotypes. The process includes rigorous …

Variability In Methotrexate Metabolites In A Cohort Of Jia Patients, Nuria Lara Castillo, Mara Becker, Marc Sudman, Susan Thompson, Laura Ramsey

Research Days

Background: Methotrexate (MTX) is the cornerstone disease-modifying anti-rheumatic drug for the treatment of Juvenile Idiopathic Arthritis (JIA). While most patients receiving MTX have a favorable outcome, approximately 30% do not respond, and several experience toxic events, suggesting interindividual difference. Furthermore, evaluation of MTX response takes several months, with the risk of missing the early “window of opportunity” for treatment. Predicting MTX response prior to administration would greatly benefit these patients and their treating physicians by saving valuable time during the early stages of the disease onset. MTX is a folate antagonist and, similar to folate, it undergoes polyglutamation inside the …

Visualizing Parcel-Level Lead Risk Using An Exterior Housing-Based Index., Neal J. Wilson, Ryan Allenbrand, Elizabeth Friedman, Kevin Kennedy, Amy Roberts, Stephen Simon

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Pediatric lead poisoning remains a persistent public health problem. Children in the US spend the preponderance of their time at home; thus, housing is an important social determinant of health. Improving health outcomes derived from housing-based sources involves differentiating the risks posed by the existing housing stock. In this paper, we developed a parcel-level lead risk index (LRI) based on external housing conditions and the year of home construction. The purpose of this study was to introduce a housing-based lead risk index (LRI), developed using retrospective data, to estimate parcel-by-parcel variation in housing-based lead risk. We described how the LRI …

Pediatric Flecainide Pharmacogenomics: A Roadmap To Delivering Precision-Based Care To Pediatrics Arrhythmias., Ronald Palmen, Mollie Walton, Jonathan B. Wagner

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Flecainide acetate is a Class 1c anti-arrhythmic with a potent sodium voltage gated channel blockade which is utilized for the second-line treatment of tachyarrhythmias in children and adults. Given its narrow therapeutic index, the individualization of drug therapy is of utmost importance for clinicians. Despite efforts to improve anti-arrhythmic drug therapy, there remain knowledge gaps regarding the impact of variation in the genes relevant to flecainide's disposition and response. This variability is compounded in developing children whose drug disposition and response pathways may remain immature. The purpose of this comprehensive review is to outline flecainide's disposition and response pathways while …

Pediatric Beta Blocker Therapy: A Comprehensive Review Of Development And Genetic Variation To Guide Precision-Based Therapy In Children, Adolescents, And Young Adults., Mollie Walton, Jonathan B. Wagner

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Beta adrenergic receptor antagonists, known as beta blockers, are one of the most prescribed medications in both pediatric and adult cardiology. Unfortunately, most of these agents utilized in the pediatric clinical setting are prescribed off-label. Despite regulatory efforts aimed at increasing pediatric drug labeling, a majority of pediatric cardiovascular drug agents continue to lack pediatric-specific data to inform precision dosing for children, adolescents, and young adults. Adding to this complexity is the contribution of development (ontogeny) and genetic variation towards the variability in drug disposition and response. In the absence of current prospective trials, the purpose of this comprehensive review …

Developing A National-Scale Exposure Index For Combined Environmental Hazards And Social Stressors And Applications To The Environmental Influences On Child Health Outcomes (Echo) Cohort., Sheena E. Martenies, Mingyu Zhang, Anne E. Corrigan, Anton Kvit, Timothy Shields, William Wheaton, Deana Around Him, Judy Aschner, Maria M. Talavera-Barber, Emily S. Barrett, Theresa M. Bastain, Casper Bendixsen, Carrie V. Breton, Nicole R. Bush, Ferdinand Cacho, Carlos A. Camargo, Kecia N. Carroll, Brian S. Carter, Andrea E. Cassidy-Bushrow, Whitney Cowell, Lisa A. Croen, Dana Dabelea, Cristiane S. Duarte, Anne L. Dunlop, Todd M. Everson, Rima Habre, Tina V. Hartert, Jennifer B. Helderman, Alison E. Hipwell, Margaret R. Karagas, Barry M. Lester, Kaja Z. Lewinn, Sheryl Magzamen, Rachel Morello-Frosch, Thomas G. O'Connor, Amy M. Padula, Michael Petriello, Sheela Sathyanarayana, Joseph B. Stanford, Tracey J. Woodruff, Rosalind J. Wright, Amii M. Kress, Program Collaborators For Environmental Influences On Child Health Outcomes

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Tools for assessing multiple exposures across several domains (e.g., physical, chemical, and social) are of growing importance in social and environmental epidemiology because of their value in uncovering disparities and their impact on health outcomes. Here we describe work done within the Environmental influences on Child Health Outcomes (ECHO)-wide Cohort Study to build a combined exposure index. Our index considered both environmental hazards and social stressors simultaneously with national coverage for a 10-year period. Our goal was to build this index and demonstrate its utility for assessing differences in exposure for pregnancies enrolled in the ECHO-wide Cohort Study. Our unitless …

Pharmacogenetic Testing For The Pediatric Gastroenterologist: Actionable Drug-Gene Pairs To Know., Tracy L. Sandritter, Rachel Chevalier, Rebecca Abt, Valentina Shakhnovich

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Gastroenterologists represent some of the earlier adopters of precision medicine through pharmacogenetic testing by embracing upfront genotyping for thiopurine S-methyltransferase nucleotide diphosphatase (TPMT) before prescribing 6-mercaptopurine or azathioprine for the treatment of inflammatory bowel disease. Over the last two decades, pharmacogenetic testing has become more readily available for other genes relevant to drug dose individualization. Common medications prescribed by gastroenterologists for conditions other than inflammatory bowel disease now have actionable guidelines, which can improve medication efficacy and safety; however, a clear understanding of how to interpret the results remains a challenge for many clinicians, precluding wide implementation of …

Climate Change Imperils Pediatric Health: Child Advocacy Through Fossil Fuel Divestment., Sandra H. Jee, Elizabeth Friedman, Ruth A. Etzel, Vi T. Nguyen, Todd L. Sack, Kathi J. Kemper

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Climate change poses an existential threat to children's health. Divestment of ownership stakes in fossil fuel companies is one tool available to pediatricians to address climate change. Pediatricians are trusted messengers regarding children's health and therefore bear a unique responsibility to advocate for climate and health policies that affect children. Among the impacts of climate change on pediatric patients are allergic rhinitis and asthma; heat-related illnesses; premature birth; injuries from severe storms and fires; vector-borne diseases; and mental illnesses. Children are disproportionately affected as well by climate-related displacement of populations, drought, water shortages, and famine. The human-generated burning of fossil …

Developmental Pharmacokinetics Of Indomethacin In Preterm Neonates: Severely Decreased Drug Clearance In The First Week Of Life., Wojciech Krzyzanski, Bradley Stockard, Andrea Gaedigk, Allison Scott, Whitney M. Nolte, Kim T. Gibson, J Steven Leeder, Tamorah Lewis

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Indomethacin is used commonly in preterm neonates for the prevention of intracranial hemorrhage and closure of an abnormally open cardiac vessel. Due to biomedical advances, the infants who receive this drug in the neonatal intensive care unit setting have become younger, smaller, and less mature (more preterm) at the time of treatment. To develop a pharmacokinetics (PK) model to aid future dosing, we designed a prospective cohort study to characterize indomethacin PK in a dynamically changing patient population. A population PK base model was created using NONMEM, and a covariate model was developed in a primary development cohort and subsequently …

Pharmacometabolomics Profiling Of Preterm Infants Validates Patterns Of Metabolism Associated With Response To Dexamethasone Treatment For Bronchopulmonary Dysplasia., Bradley Stockard, Cheri Gauldin, William E. Truog, Tamorah Lewis

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Bronchopulmonary dysplasia (BPD) is one of the most common health complications of premature birth. Corticosteroids are commonly used for treatment of BPD, but their use is challenging due to variability in treatment response. Previous pharmacometabolomics study has established patterns of metabolite levels with response to dexamethasone. We obtained additional patient samples for metabolomics analysis to find associations between the metabolome and dexamethasone response in a validation cohort. A total of 14 infants provided 15 plasma and 12 urine samples. The measure of treatment response was the calculated change in respiratory severity score (deltaRSS) from pre-to-post treatment. Each metabolite was assessed …

Pharmacometabolomics Profiling Of Preterm Infants Validates Patterns Of Metabolism Associated With Response To Dexamethasone Treatment For Bronchopulmonary Dysplasia, Bradley C. Stockard

Research Days

Background: Bronchopulmonary dysplasia (BPD) is one of the most common health complications of premature birth. Corticosteroids are commonly used for treatment of BPD, but their use is challenging due to variability in treatment response.

Objectives/Goal: Previous pharmacometabolomics study has established patterns of metabolite levels with response to dexamethasone. We obtained additional patient samples for metabolomics analysis to find associations between the metabolome and dexamethasone response in a validation cohort.

Methods/Design: 14 infants provided 15 plasma and 12 urine samples. The measure of treatment response was the calculated change in respiratory severity score (deltaRSS) from pre-to-post treatment. Each metabolite was assessed …

Case Report: Pharmacogenetics Applied To Precision Psychiatry Could Explain The Outcome Of A Patient With A New Cyp2d6 Genotype, Elena Marcos-Vadillo, Lorena Carrascal-Laso, Ignacio Ramos-Gallego, Andrea Gaedigk, Belén García-Berrocal, Eduardo Mayor-Toranzo, Alfonso Sevillano-Jiménez, Almudena Sánchez, María Isidoro-García, Manuel Franco-Martín

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Precision medicine applied to psychiatry provides new insight into the promising field of precision psychiatry. Psychotic disorders are heterogeneous, complex, chronic, and severe mental disorders. Not only does the prognosis and the course of the disease vary among patients suffering from psychotic disorders, but the treatment response varies as well. Although antipsychotic drugs are the cornerstone of the treatment of schizophrenia, many patients only partially respond to these drugs. Furthermore, patients often experience adverse events which can lead to poor treatment adherence. Interindividual variability in drug response could be related to age, gender, ethnicity, lifestyle factors, pharmacological interactions, obesity, and …

Ten Years Of Experience Support Pharmacogenetic Testing To Guide Individualized Drug Therapy., María Celsa Peña-Martín, Belén García-Berrocal, Almudena Sánchez-Martín, Elena Marcos-Vadillo, María Jesús García-Salgado, Santiago Sánchez, Carolina Lorenzo, David González-Parra, Francisco Sans, Manuel Franco, Andrea Gaedigk, María José Mateos-Sexmero, Catalina Sanz, María Isidoro-García

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Precision medicine utilizing the genetic information of genes involved in the metabolism and disposition of drugs can not only improve drug efficacy but also prevent or minimize adverse events. Polypharmacy is common among multimorbid patients and is associated with increased adverse events. One of the main objectives in health care is safe and efficacious drug therapy, which is directly correlated to the individual response to treatment. Precision medicine can increase drug safety in many scenarios, including polypharmacy. In this report, we share our experience utilizing precision medicine over the past ten years. Based on our experience using pharmacogenetic (PGx)-informed prescribing, …

Evaluation Of Placentation And The Role Of The Aryl Hydrocarbon Receptor Pathway In A Rat Model Of Dioxin Exposure., Khursheed Iqbal, Stephen H. Pierce, Keisuke Kozai, Pramod Dhakal, Regan L. Scott, Katherine F Roby, Carrie A. Vyhlidal, Michael J. Soares

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Background: Our environment is replete with chemicals that can affect embryonic and extraembryonic development. Dioxins, such as 2,3,7,8-tetrachlorodibenzo-p" role="presentation" style="box-sizing: inherit; display: inline-block; line-height: 0; font-size: 18.08px; overflow-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; margin: 0px; padding: 1px 0px; position: relative;">pp-dioxin (TCDD), are compounds affecting development through the aryl hydrocarbon receptor (AHR).

Objectives: The purpose of this investigation was to examine the effects of TCDD exposure on pregnancy and placentation and to evaluate roles for AHR and cytochrome P450 1A1 (CYP1A1) in TCDD action.

Methods: Actions …

Profiling Pretomanid As A Therapeutic Option For Tb Infection: Evidence To Date., Stephani L. Stancil, Fuad Mirzayev, Susan M. Abdel-Rahman

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Tuberculosis (TB) is the most deadly infectious disease globally. Although most individuals achieve a cure, a substantial portion develop multi-drug resistant TB which is exceedingly difficult to treat, and the number of effective agents is dwindling. Development of new anti-tubercular medications is imperative to combat existing drug resistance and accelerate global eradication of TB. Pretomanid (PA-824) represents one of the newest drug classes (ie, nitroimidazooxazines) approved in 2019 by the United States Food and Drug Administration as part of a multi-drug regimen (with bedaquiline and linezolid, BPaL) and recommended by the World Health Organization (WHO) to treat extensively-resistant (XR-TB) and …

Cyp2d6 Genetic Variation And Its Implication For Vivax Malaria Treatment In Madagascar, Rajeev K. Mehlotra, Andrea Gaedigk, Rosalind E. Howes, Tovonahary A. Rakotomanga, Arsene C. Ratsimbasoa, Peter A. Zimmerman

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Plasmodium vivax is one of the five human malaria parasite species, which has a wide geographical distribution and can cause severe disease and fatal outcomes. It has the ability to relapse from dormant liver stages (hypnozoites), weeks to months after clearance of the acute blood-stage infection. An 8-aminoquinoline drug primaquine (PQ) can clear the hypnozoites, and thus can be used as an anti-relapse therapeutic agent. Recently, a number of studies have found that its efficacy is compromised by polymorphisms in the cytochrome P450 2D6 (CYP2D6) gene; decreased or absence of CYP2D6 activity contributes to PQ therapeutic failure. The …

Efficacy Of Weight Reduction On Pediatric Nonalcoholic Fatty Liver Disease: Opportunities To Improve Treatment Outcomes Through Pharmacotherapy., Chance S. Friesen, Chelsea Hosey-Cojocari, Sherwin S. Chan, Iván L. Csanaky, Jonathan B. Wagner, Brooke Sweeney, Alec Friesen, Jason D. Fraser, Valentina Shakhnovich

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Obesity is the single greatest risk factor for nonalcoholic fatty liver disease (NAFLD). Without intervention, most pediatric patients with NAFLD continue to gain excessive weight, making early, effective weight loss intervention key for disease treatment and prevention of NAFLD progression. Unfortunately, outside of a closely monitored research setting, which is not representative of the real world, lifestyle modification success for weight loss in children is low. Bariatric surgery, though effective, is invasive and can worsen NAFLD postoperatively. Thus, there is an evolving and underutilized role for pharmacotherapy in children, both for weight reduction and NAFLD management. In this perspective article, …

Effect Of Crohn's Disease On Villous Length And Cyp3a4 Expression In The Pediatric Small Intestine., Carrie A. Vyhlidal, Brian D. Chapron, Atif Ahmed, Vivekanand Singh, Rebecca Casini, Valentina Shakhnovich

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Changes in absorptive capacity and first-pass metabolism in the small intestine affect oral drug bioavailability. Characterization of such changes as a consequence of inflammation is important for developing physiologically-based pharmacokinetic (PBPK) models for inflammatory bowel disease. We sought to elucidate the impact of small intestinal Crohn's disease (CD) on villous length and CYP3A4 expression in children. Freshly frozen duodenal and terminal ileum (TI) biopsies from 107 children (1-19 years) with and without CD were evaluated for active inflammation. Villous length and CYP3A4 mRNA/protein expression were compared among regions of active and inactive inflammation in CD and controls. A twofold reduction …

Utilization Of The Naranjo Scale To Evaluate Adverse Drug Reactions At A Free-Standing Children's Hospital., Madhavi Murali, Sarah Suppes, Keith Feldman, Jennifer Goldman

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The relationship between the Naranjo scaling system and pediatric adverse drug reactions (ADR) is poorly understood. We performed a retrospective review of 1,676 pediatric ADRs documented at our hospital from 2014-2018. We evaluated patient demographics, implicated medication, ADR severity, calculated Naranjo score, associated symptoms, and location within the hospital in which the ADR was documented. ADR severity was poorly correlated with Naranjo interpretation. Out of the 10 Naranjo scale questions, 4 had a response of "unknown" greater than 85% of the time. Cardiovascular and oncological/immunologic agents were more likely to have a probable or definite Naranjo interpretation compared to antimicrobials. …

Retrospective Review Of Pharmacogenetic Testing At An Academic Children's Hospital., Timothy A. Roberts, Jennifer A. Wagner, Tracy L. Sandritter, Benjamin T. Black, Andrea Gaedigk, Stephani L. Stancil

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There is limited evidence to support pharmacogenetic (PGx) testing in children. We conducted a retrospective review of PGx testing among 452 patients at an academic children's hospital to determine the potential utility of PGx in diseases of childhood and to identify targets for future pediatric pharmacogenetic research. An actionable gene-drug pair associated with the 28 genes tested (Clinical Pharmacogenetics Implementation Consortium (CPIC) level A or B, Pharmacogenomics Knowledge Base (PharmGKB) level 1A or B, or US Food and Drug Administration (FDA) recommendation and a PharmGKB level) was present in 98.7% of patients. We identified 203 actionable gene-drug-diagnosis groups based on …

Effect Of Intrauterine Smoke Exposure On Microrna-15a Expression In Human Lung Development And Subsequent Asthma Risk., Sunita Sharma, Alvin T. Kho, Divya Chhabra, Kathleen Haley, Carrie A. Vyhlidal, R Gaedigk, J Steven Leeder, Kelan G. Tantisira, Benjamin Raby, Scott T. Weiss

Manuscripts, Articles, Book Chapters and Other Papers

Background: In utero smoke (IUS) exposure is associated with asthma susceptibility.

Objective: We sought to test the hypothesis that changes in miRNA expression by IUS exposure during human lung development is associated with asthma susceptibility.

Methods: Gene expression was profiled from 53 IUS unexposed and 51 IUS exposed human fetal lung tissues. We tested for the differential expression of miRNAs across post-conception age and by IUS using linear models with covariate adjustment. We tested the IUS-associated miRNAs for association with their gene expression targets using pair-wise inverse correlation. Using our mouse model, we investigated the persistence of the IUS-associated miRNA …

Transfer Learning Enables Prediction Of Cyp2d6 Haplotype Function., Gregory Mcinnes, Rachel Dalton, Katrin Sangkuhl, Michelle Whirl-Carrillo, Seung-Been Lee, Philip S. Tsao, Andrea Gaedigk, Russ B. Altman, Erica L. Woodahl

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Cytochrome P450 2D6 (CYP2D6) is a highly polymorphic gene whose protein product metabolizes more than 20% of clinically used drugs. Genetic variations in CYP2D6 are responsible for interindividual heterogeneity in drug response that can lead to drug toxicity and ineffective treatment, making CYP2D6 one of the most important pharmacogenes. Prediction of CYP2D6 phenotype relies on curation of literature-derived functional studies to assign a functional status to CYP2D6 haplotypes. As the number of large-scale sequencing efforts grows, new haplotypes continue to be discovered, and assignment of function is challenging to maintain. To address this challenge, we have trained a convolutional neural …

Cyp2d6 Predicts Plasma Donepezil Concentrations In A Cohort Of Thai Patients With Mild To Moderate Dementia., Monpat Chamnanphon, Sorawit Wainipitapong, Teeravut Wiwattarangkul, Phenphichcha Chuchuen, Kunathip Nissaipan, Weeraya Phaisal, Sookjaroen Tangwongchai, Chonlaphat Sukasem, Supeecha Wittayalertpanya, Andrea Gaedigk, Daruj Aniwattanapong, Pajaree Chariyavilaskul

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Purpose: Donepezil, a drug frequently used to treat dementia, is mainly metabolized by cytochrome P450 2D6 (CYP2D6). This study investigated the relationships between CYP2D6 genotype and activity scores as well as predicted phenotype of plasma donepezil concentrations in 86 Thai dementia participants.

Materials and methods: CYP2D6 was genotyped using bead-chip technology (Luminex xTAG® v.3). Steady-state trough plasma donepezil concentrations were measured using high-performance liquid chromatography.

Results: Sixteen genotypes were found but the most frequent genotypes detected among our participants were CYP2D6*10/*10 (27.9%) and *1/*10 (26.7%). One-third of the participants had an activity score of 1.25 which predicted that they were …

Ontogeny Related Changes In The Pediatric Liver Metabolome., Christopher M. Wilson, Qian Li, R Gaedigk, Chengpeng Bi, Saskia N. De Wildt, J Steven Leeder, Brooke L. Fridley

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Background: A major challenge in implementing personalized medicine in pediatrics is identifying appropriate drug dosages for children. The majority of drug dosing studies have been based on adult populations, often with modification of the dosing for children based on size and weight. However, the growth and development experienced by children between birth and adulthood represents a dynamically changing biological system, with implications for effective drug dosing, efficacy as well as potential drug toxicity. The purpose of this study was to apply a metabolomics approach to gain preliminary insights into the ontogeny of liver function from newborn to adolescent.

Methods: Metabolites …

Medicine And Media: The Ranitidine Debate., Jennifer A. Wagner, Jennifer Colombo

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Ranitidine has been the topic of recent media reports. Current findings, confirmed by the US Food and Drug Administration, indicate that some ranitidine products contain a substance that may be carcinogenic. Providers and patients require additional information on the risks of continuing therapy vs. the benefits of the medication. This article comments on what is currently known about the evolving situation of elevated N-nitrosodimethylamine levels in ranitidine and the limits of the existing information to assess best practices.

Indomethacin Exposure Is Associated With Birthweight In Extremely Preterm Infants: Non-Standard Exposure With Standard Weight-Based Dosing, Bradley C. Stockard

Research Days

No abstract provided.

Long-Distance Phasing Of A Tentative "Enhancer" Single-Nucleotide Polymorphism With Yp2d6 Star Allele Definitions, Erin C. Boone, Wendy Y. Wang, R Gaedigk, Mariana Cherner, Anick Bérard, J Steven Leeder, Neil A. Miller, Andrea Gaedigk

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Background: The CYP2D6 gene locus has been extensively studied over decades, yet a portion of variability in CYP2D6 activity cannot be explained by known sequence variations within the gene, copy number variation, or structural rearrangements. It was proposed that rs5758550, located 116 kb downstream of the CYP2D6 gene locus, increases gene expression and thus contributes to variability in CYP2D6 activity. This finding has, however, not been validated. The purpose of the study was to address a major technological barrier, i.e., experimentally linking rs5758550, also referred to as the "enhancer" single-nucleotide polymorphism (SNP), to CYP2D6 haplotypes >100 kb away. To overcome …