Publications by authors named "Eric Blomme"

61 Publications

Chemical Toxicology and Medicinal Chemistry: A Special Issue Promoting Scientific Advances for Safer Medicines, Part 1.

Chem Res Toxicol 2020 01;33(1)

Department of Health Sciences and Technology ETH Zurich , 8092 Zurich , Switzerland.

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http://dx.doi.org/10.1021/acs.chemrestox.9b00496DOI Listing
January 2020

Managing the challenge of drug-induced liver injury: a roadmap for the development and deployment of preclinical predictive models.

Nat Rev Drug Discov 2020 02 20;19(2):131-148. Epub 2019 Nov 20.

Department of Molecular and Clinical Pharmacology, MRC Centre for Drug Safety Science, University of Liverpool, Liverpool, UK.

Drug-induced liver injury (DILI) is a patient-specific, temporal, multifactorial pathophysiological process that cannot yet be recapitulated in a single in vitro model. Current preclinical testing regimes for the detection of human DILI thus remain inadequate. A systematic and concerted research effort is required to address the deficiencies in current models and to present a defined approach towards the development of new or adapted model systems for DILI prediction. This Perspective defines the current status of available models and the mechanistic understanding of DILI, and proposes our vision of a roadmap for the development of predictive preclinical models of human DILI.
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http://dx.doi.org/10.1038/s41573-019-0048-xDOI Listing
February 2020

Drug Metabolism and Toxicology Special Issue Call for Papers.

Chem Res Toxicol 2019 06;32(6):943

Department of Health Sciences and Technology , Eidgenossische Technische Hochschule (ETH) Zurich , 8092 Zurich , Switzerland.

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http://dx.doi.org/10.1021/acs.chemrestox.9b00138DOI Listing
June 2019

Comparison of RNA-Seq and Microarray Gene Expression Platforms for the Toxicogenomic Evaluation of Liver From Short-Term Rat Toxicity Studies.

Front Genet 2018 22;9:636. Epub 2019 Jan 22.

Investigative Toxicology and Pathology, Global Preclinical Safety, AbbVie, North Chicago, IL, United States.

Gene expression profiling is a useful tool to predict and interrogate mechanisms of toxicity. RNA-Seq technology has emerged as an attractive alternative to traditional microarray platforms for conducting transcriptional profiling. The objective of this work was to compare both transcriptomic platforms to determine whether RNA-Seq offered significant advantages over microarrays for toxicogenomic studies. RNA samples from the livers of rats treated for 5 days with five tool hepatotoxicants (α-naphthylisothiocyanate/ANIT, carbon tetrachloride/CCl, methylenedianiline/MDA, acetaminophen/APAP, and diclofenac/DCLF) were analyzed with both gene expression platforms (RNA-Seq and microarray). Data were compared to determine any potential added scientific (i.e., better biological or toxicological insight) value offered by RNA-Seq compared to microarrays. RNA-Seq identified more differentially expressed protein-coding genes and provided a wider quantitative range of expression level changes when compared to microarrays. Both platforms identified a larger number of differentially expressed genes (DEGs) in livers of rats treated with ANIT, MDA, and CCl compared to APAP and DCLF, in agreement with the severity of histopathological findings. Approximately 78% of DEGs identified with microarrays overlapped with RNA-Seq data, with a Spearman's correlation of 0.7 to 0.83. Consistent with the mechanisms of toxicity of ANIT, APAP, MDA and CCl, both platforms identified dysregulation of liver relevant pathways such as Nrf2, cholesterol biosynthesis, eiF2, hepatic cholestasis, glutathione and LPS/IL-1 mediated RXR inhibition. RNA-Seq data showed additional DEGs that not only significantly enriched these pathways, but also suggested modulation of additional liver relevant pathways. In addition, RNA-Seq enabled the identification of non-coding DEGs that offer a potential for improved mechanistic clarity. Overall, these results indicate that RNA-Seq is an acceptable alternative platform to microarrays for rat toxicogenomic studies with several advantages. Because of its wider dynamic range as well as its ability to identify a larger number of DEGs, RNA-Seq may generate more insight into mechanisms of toxicity. However, more extensive reference data will be necessary to fully leverage these additional RNA-Seq data, especially for non-coding sequences.
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http://dx.doi.org/10.3389/fgene.2018.00636DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6349826PMC
January 2019

Use of toxicogenomics in drug safety evaluation: Current status and an industry perspective.

Regul Toxicol Pharmacol 2018 Jul 19;96:18-29. Epub 2018 Apr 19.

Novartis Pharma AG, Translational Medicine at the Novartis Institutes of Biomedical Research, Basel, Switzerland.

Toxicogenomics held great promise as an approach to enable early detection of toxicities induced by xenobiotics; however, there remain questions regarding the impact of the discipline on pharmaceutical nonclinical safety assessment. To understand the current state of toxicogenomics in the sector, an industry group surveyed companies to determine the frequency of toxicogenomics use in in vivo studies at various stages of drug discovery and development and to assess how toxicogenomics use has evolved over time. Survey data were compiled during 2016 from thirteen pharmaceutical companies. Toxicogenomic analyses were infrequently conducted in the development phase and when performed were done to address specific mechanistic questions. Prior to development, toxicogenomics use was more frequent; however, there were significant differences in approaches among companies. Across all phases, gaining mechanistic insight was the most frequent reason cited for pursing toxicogenomics with few companies using toxicogenomics to predict toxicities. These data were consistent with the commentary submitted in response to survey questions asking companies to describe the evolution of their toxicogenomics strategy. Overall, these survey data indicate that toxicogenomics is not widely used as a predictive tool in the pharmaceutical industry but is used regularly by some companies and serves a broader role in mechanistic investigations and as a complement to other technologies.
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http://dx.doi.org/10.1016/j.yrtph.2018.04.011DOI Listing
July 2018

Test systems in drug discovery for hazard identification and risk assessment of human drug-induced liver injury.

Expert Opin Drug Metab Toxicol 2017 Jul 28;13(7):767-782. Epub 2017 Jun 28.

o Institute of Translational Medicine , University of Liverpool , Liverpool , UK.

Introduction: The liver is an important target for drug-induced toxicities. Early detection of hepatotoxic drugs requires use of well-characterized test systems, yet current knowledge, gaps and limitations of tests employed remains an important issue for drug development. Areas Covered: The current state of the science, understanding and application of test systems in use for the detection of drug-induced cytotoxicity, mitochondrial toxicity, cholestasis and inflammation is summarized. The test systems highlighted herein cover mostly in vitro and some in vivo models and endpoint measurements used in the assessment of small molecule toxic liabilities. Opportunities for research efforts in areas necessitating the development of specific tests and improved mechanistic understanding are highlighted. Expert Opinion: Use of in vitro test systems for safety optimization will remain a core activity in drug discovery. Substantial inroads have been made with a number of assays established for human Drug-induced Liver Injury. There nevertheless remain significant gaps with a need for improved in vitro tools and novel tests to address specific mechanisms of human Drug-Induced Liver Injury. Progress in these areas will necessitate not only models fit for application, but also mechanistic understanding of how chemical insult on the liver occurs in order to identify translational and quantifiable readouts for decision-making.
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http://dx.doi.org/10.1080/17425255.2017.1341489DOI Listing
July 2017

Acyl glucuronide metabolites: Implications for drug safety assessment.

Toxicol Lett 2017 Apr 7;272:1-7. Epub 2017 Mar 7.

Abbvie, Development Sciences, Department of Preclinical Safety, United States.

Acyl glucuronides are important metabolites of compounds with carboxylic acid moieties and have unique properties that distinguish them from other phase 2 metabolites. In particular, in addition to being often unstable, acyl glucuronide metabolites can be chemically reactive leading to covalent binding with macromolecules and toxicity. While there is circumstantial evidence that drugs forming acyl glucuronide metabolites can be associated with rare, but severe idiosyncratic toxic reactions, many widely prescribed drugs with good safety records are also metabolized through acyl glucuronidation. Therefore, there is a need to understand the various factors that can affect the safety of acyl glucuronide-producing drugs including the rate of acyl glucuronide formation, the relative reactivity of the acyl glucuronide metabolite formed, the rate of elimination, potential proteins being targeted, and the rate of aglucuronidation. In this review, these factors are discussed and various approaches to de-risk the safety liabilities of acyl glucuronide metabolites are evaluated.
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http://dx.doi.org/10.1016/j.toxlet.2017.03.003DOI Listing
April 2017

Potential functional and pathological side effects related to off-target pharmacological activity.

J Pharmacol Toxicol Methods 2017 Sep 16;87:108-126. Epub 2017 Feb 16.

AbbVie Inc., 1 North Waukegan Road, North Chicago, IL 60064, USA.

Most pharmaceutical companies test their discovery-stage proprietary molecules in a battery of in vitro pharmacology assays to try to determine off-target interactions. During all phases of drug discovery and development, various questions arise regarding potential side effects associated with such off-target pharmacological activity. Here we present a scientific literature curation effort undertaken to determine and summarize the most likely functional and pathological outcomes associated with interactions at 70 receptors, enzymes, ion channels and transporters with established links to adverse effects. To that end, the scientific literature was reviewed using an on-line database, and the most commonly reported effects were summarized in tabular format. The resultant table should serve as a practical guide for research scientists and clinical investigators for the prediction and interpretation of adverse side effects associated with molecules interacting with components of this screening battery.
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http://dx.doi.org/10.1016/j.vascn.2017.02.020DOI Listing
September 2017

Key Challenges and Opportunities Associated with the Use of In Vitro Models to Detect Human DILI: Integrated Risk Assessment and Mitigation Plans.

Biomed Res Int 2016;2016:9737920. Epub 2016 Sep 5.

Genentech, 1 DNA Way, South San Francisco, CA 94080, USA.

Drug-induced liver injury (DILI) is a major cause of late-stage clinical drug attrition, market withdrawal, black-box warnings, and acute liver failure. Consequently, it has been an area of focus for toxicologists and clinicians for several decades. In spite of considerable efforts, limited improvements in DILI prediction have been made and efforts to improve existing preclinical models or develop new test systems remain a high priority. While prediction of intrinsic DILI has improved, identifying compounds with a risk for idiosyncratic DILI (iDILI) remains extremely challenging because of the lack of a clear mechanistic understanding and the multifactorial pathogenesis of idiosyncratic drug reactions. Well-defined clinical diagnostic criteria and risk factors are also missing. This paper summarizes key data interpretation challenges, practical considerations, model limitations, and the need for an integrated risk assessment. As demonstrated through selected initiatives to address other types of toxicities, opportunities exist however for improvement, especially through better concerted efforts at harmonization of current, emerging and novel in vitro systems or through the establishment of strategies for implementation of preclinical DILI models across the pharmaceutical industry. Perspectives on the incorporation of newer technologies and the value of precompetitive consortia to identify useful practices are also discussed.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5027328PMC
http://dx.doi.org/10.1155/2016/9737920DOI Listing
September 2016

Simultaneous measurement of arterial and left ventricular pressure in conscious freely moving rats by telemetry.

J Pharmacol Toxicol Methods 2016 May-Jun;79:23-33. Epub 2016 Jan 9.

Research and Development, Abbvie Inc., North Chicago, IL 60064, USA.

Comprehensive cardiovascular assessment in conscious rodents by utilizing telemetry has been limited by the restriction of current devices to one pressure channel. The purpose of this study was to test and validate a dual pressure transmitter that allows the simultaneous measurement of arterial pressure (AP) and left ventricular pressure (LVP) in conscious freely moving rats. Six rats were surgically implanted with dual pressure transmitters. Baseline hemodynamics and circadian rhythm were observed to return within 7days. AP, heart rate (HR), LVP and indices of left ventricular contractility were stable and demonstrated a prominent circadian rhythm over a two-week period of uninterrupted recordings. Administration of the vasodilator nifedipine produced the anticipated dose-dependent decrease in AP which was accompanied by a baroreflex mediated increase in HR and cardiac contractility. The negative inotrope verapamil produced the expected dose-dependent decreases in AP and cardiac contractility. Finally, a terminal validation of the dual pressure transmitter was performed under anesthesia by measuring AP and LVP simultaneously via telemetry and from a fluid filled arterial catheter and an intraventricular Millar catheter, respectively. A range of pressures and cardiac contractility were studied by administering sequential intravenous infusions of the positive inotrope dobutamine followed by verapamil. Linear regression analysis revealed a high level of agreement between pressures measured by the dual pressure transmitter and the exteriorized catheters. Histopathologic analysis of the heart revealed mild peri-catheter fibrosis. In conclusion, the simultaneous measurement of AP and LVP offers the potential for more detailed cardiovascular assessment in conscious rats.
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http://dx.doi.org/10.1016/j.vascn.2016.01.003DOI Listing
December 2016

Toxicology Strategies for Drug Discovery: Present and Future.

Chem Res Toxicol 2016 Apr 4;29(4):473-504. Epub 2015 Dec 4.

Drug Safety Research and Development, Pfizer , Eastern Point Road, Groton, Connecticut 06340, United States.

Attrition due to nonclinical safety represents a major issue for the productivity of pharmaceutical research and development (R&D) organizations, especially during the compound optimization stages of drug discovery and the early stages of clinical development. Focusing on decreasing nonclinical safety-related attrition is not a new concept, and various approaches have been experimented with over the last two decades. Front-loading testing funnels in Discovery with in vitro toxicity assays designed to rapidly identify unfavorable molecules was the approach adopted by most pharmaceutical R&D organizations a few years ago. However, this approach has also a non-negligible opportunity cost. Hence, significant refinements to the "fail early, fail often" paradigm have been proposed recently to reflect the complexity of accurately categorizing compounds with early data points without taking into account other important contextual aspects, in particular efficacious systemic and tissue exposures. This review provides an overview of toxicology approaches and models that can be used in pharmaceutical Discovery at the series/lead identification and lead optimization stages to guide and inform chemistry efforts, as well as a personal view on how to best use them to meet nonclinical safety-related attrition objectives consistent with a sustainable pharmaceutical R&D model. The scope of this review is limited to small molecules, as large molecules are associated with challenges that are quite different. Finally, a perspective on how several emerging technologies may impact toxicity evaluation is also provided.
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http://dx.doi.org/10.1021/acs.chemrestox.5b00407DOI Listing
April 2016

Veterinary oncology: Translating research advances into innovative therapeutic and diagnostic options.

Authors:
Eric A G Blomme

Vet J 2015 Aug 8;205(2):117-9. Epub 2015 Jun 8.

Scientific Editor, The Veterinary Journal. AbbVie Inc., North Chicago, IL, USA.. Electronic address:

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http://dx.doi.org/10.1016/j.tvjl.2015.06.005DOI Listing
August 2015

Targeted drug delivery in oncology: where drug discovery meets physics.

Vet J 2015 Aug 8;205(2):120-1. Epub 2015 May 8.

Scientific Editor, The Veterinary Journal; Senior Research Fellow, Investigative Toxicology and Pathology, AbbVie, North Chicago, IL, USA. Electronic address:

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http://dx.doi.org/10.1016/j.tvjl.2015.04.034DOI Listing
August 2015

Drug-drug interactions: an evolving science in need of experimental models and systems.

Authors:
Eric A Blomme

Vet J 2014 Jul 21;201(1):1-2. Epub 2014 Apr 21.

The Veterinary Journal. Electronic address:

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http://dx.doi.org/10.1016/j.tvjl.2014.04.014DOI Listing
July 2014

Circulating microRNA 122 in the methionine and choline-deficient mouse model of non-alcoholic steatohepatitis.

J Appl Toxicol 2014 Jun 12;34(6):726-32. Epub 2013 Nov 12.

Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ, 85721, USA.

Non-alcoholic steatohepatitis (NASH) is a progressive form of non-alcoholic fatty liver disease (NAFLD) and is a major cause of liver cirrhosis and hepatic failure. The methionine choline-deficient diet (MCD) is a frequently used hepatotoxicity animal model of NASH that induces hepatic transaminase (ALT, AST) elevations and hepatobiliary histological changes similar to those observed in human NASH. Liver-specific microRNA-122 (miR-122) has been shown as a key regulator of cholesterol and fatty acid metabolism in adult liver, and has recently been proposed as a sensitive and specific circulating biomarker of hepatic injury. The purpose of this study was to assess miR-122 serum levels in mice receiving an MCD diet for 0, 3, 7, 14, 28 and 56 days and compare the performance vs. routine clinical chemistry when benchmarked against the histopathological liver findings. MiR-122 levels were quantified in serum using RT-qPCR. Both miR-122 and ALT/AST levels were significantly elevated in serum at all timepoints. MiR-122 levels increased on average by 40-fold after 3 days of initiating the MCD diet, whereas ALT and AST changes were 4.8- and 3.3-fold, respectively. In general, miR-122 levels remained elevated across all time points, whereas the ALT/AST increases were less robust but correlated with the progressive severity of NASH as assessed by histopathology. In conclusion, serum levels of miR-122 can potentially be used as a sensitive biomarker for the early detection of hepatotoxicity and can aid in monitoring the extent of NAFLD-associated liver injury in mouse efficacy models.
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http://dx.doi.org/10.1002/jat.2960DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4004685PMC
June 2014

Cerebrospinal fluid biomarkers: exploiting advances in humans to improve veterinary care.

Vet J 2013 Aug 12;197(2):113-4. Epub 2013 Jun 12.

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http://dx.doi.org/10.1016/j.tvjl.2013.04.026DOI Listing
August 2013

Transcriptomic evaluation of canine suspension-shipped and pre-plated hepatocytes: comparison to liver.

Toxicol Mech Methods 2013 Sep 14;23(7):479-90. Epub 2013 Jun 14.

AbbVie Inc., 1 North Waukegan Road, North Chicago, IL 60064, USA.

Introduction: In vitro assays using rat and human hepatocytes are used for hepatotoxicity studies; however, in vitro methods are less established for canine hepatocytes. In particular, little is known about the effects of plating and culture on canine hepatocytes. The goal of this study was to conduct a descriptive analysis of an in vitro canine hepatocyte system to evaluate its utility and limitations. The study objectives were to determine if canine hepatocytes shipped in suspension or pre-plated were transcriptomically different from one another and their liver of origin, and to understand temporal transcriptomic changes.

Materials And Methods: Frozen canine liver samples were delivered on dry ice; hepatocytes from these livers were delivered in a cell/media suspension (S) or pre-plated (P). Hepatocytes were harvested at arrival and after up to 120 hr of culture in naïve media, or after 48 hr treatment with prototypical enzyme inducing xenobiotics (phenobarbital or rifampin).

Results: A global transcriptomic comparison between liver and hepatocyte preparations indicated that the transcriptome was affected post-plating; transporters and genes involved in xenobiotic metabolism were generally down-regulated. Basal mRNA levels of CYP3A12 and CYP2B11 decreased temporally; after 120 hr CYP3A12 levels decreased by 1000-fold. CYP3A12 and CYP2B11 induction after phenobarbital or rifampin treatment was robust in both cell types but stronger in S cells.

Conclusions: These results indicate that S and P hepatocytes cultured under the current conditions are appropriate for specific in vitro tests. Further characterization of endpoints should be conducted for a thorough understanding of the model's limitations.
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http://dx.doi.org/10.3109/15376516.2013.796031DOI Listing
September 2013

AhR activation underlies the CYP1A autoinduction by A-998679 in rats.

Front Genet 2012 26;3:213. Epub 2012 Oct 26.

Abbott Laboratories, Department of Cellular, Molecular, and Exploratory Toxicology Abbott Park, IL, USA.

Xenobiotic-mediated induction of cytochrome P450 (CYP) drug metabolizing enzymes (DMEs) is frequently encountered in drug discovery and can influence disposition, pharmacokinetic, and toxicity profiles. The CYP1A subfamily of DMEs plays a central role in the biotransformation of several drugs and environmental chemicals. Autoinduction of drugs through CYP3A enzymes is a common mechanism for their enhanced clearance. However, autoinduction via CYP1A is encountered less frequently. In this report, an experimental compound, A-998679 [3-(5-pyridin-3-yl-1,2,4-oxadiazol-3-yl) benzonitrile], was shown to enhance its own clearance via induction of Cyp1a1 and Cyp1a2. Rats were dosed for 5 days with 30, 100, and 200 mg/kg/day A-998679. During the dosing period, the compound's plasma AUC decreased at 30 mg/kg (95%) and 100 mg/kg (80%). Gene expression analysis and immunohistochemistry of the livers showed a large increase in the mRNA and protein levels of Cyp1a, which was involved in the biotransformation of A-998679. Induction of CYP1A was confirmed in primary rat, human, and dog hepatocytes. The compound also weakly inhibited CYP1A2 in human liver microsomes. A-998679 activated the aryl hydrocarbon receptor (AhR) in a luciferase gene reporter assay in HepG2 cells, upregulated expression of genes associated with AhR activation in rat liver and enhanced nuclear migration of AhR in HepG2 cells. Collectively these results demonstrate that A-998679 is an AhR activator that induces Cyp1a1 and Cyp1a2 expression, resulting in an autoinduction phenomenon. The unique properties of A-998679, along with its novel structure distinct from classical polycyclic aromatic hydrocarbons (PAHs), may warrant its further evaluation as a tool compound for use in studies involving AhR biology and CYP1A-related mechanisms of drug metabolism and toxicity.
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http://dx.doi.org/10.3389/fgene.2012.00213DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3481155PMC
November 2012

Computer-assisted imaging algorithms facilitate histomorphometric quantification of kidney damage in rodent renal failure models.

J Pathol Inform 2012 28;3:20. Epub 2012 Apr 28.

Investigative Toxicology and Pathology, Abbott Laboratories, 100 Abbott Park Rd, Abbott Park, IL 60064, USA.

Introduction: Surgical 5/6 nephrectomy and adenine-induced kidney failure in rats are frequently used models of progressive renal failure. In both models, rats develop significant morphological changes in the kidneys and quantification of these changes can be used to measure the efficacy of prophylactic or therapeutic approaches. In this study, the Aperio Genie Pattern Recognition technology, along with the Positive Pixel Count, Nuclear and Rare Event algorithms were used to quantify histological changes in both rat renal failure models.

Methods: Analysis was performed on digitized slides of whole kidney sagittal sections stained with either hematoxylin and eosin or immunohistochemistry with an anti-nestin antibody to identify glomeruli, regenerating tubular epithelium, and tubulointerstitial myofibroblasts. An anti-polymorphonuclear neutrophil (PMN) antibody was also used to investigate neutrophil tissue infiltration.

Results: Image analysis allowed for rapid and accurate quantification of relevant histopathologic changes such as increased cellularity and expansion of glomeruli, renal tubular dilatation, and degeneration, tissue inflammation, and mineral aggregation. The algorithms provided reliable and consistent results in both control and experimental groups and presented a quantifiable degree of damage associated with each model.

Conclusion: These algorithms represent useful tools for the uniform and reproducible characterization of common histomorphologic features of renal injury in rats.
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http://dx.doi.org/10.4103/2153-3539.95456DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3352620PMC
October 2012

N-vinylpyrrolidone dimer, a novel formulation excipient, causes hepatic and thyroid hypertrophy through the induction of hepatic microsomal enzymes in rats.

Toxicol Lett 2012 Jan 20;208(1):82-91. Epub 2011 Oct 20.

Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, IL, USA.

N-vinylpyrrolidone dimer (VPD) is a novel experimental formulation excipient intended for preclinical toxicology studies. In a previous 4-week toxicity study, VPD induced dose-dependent hepatocellular and thyroid gland hypertrophy in Sprague-Dawley (SD) rats. The objectives of the current investigation were to define the underlying molecular mechanisms of these changes. Two separate studies were conducted using male SD rats, daily doses of 300, 1000 or 3,000 mg/kg of VPD, and a positive control (phenobarbital at 75 mg/kg/day): (1) a 28-day study to monitor thyroid hormone levels after 7 and 28 days of dosing; (2) a 5-day study to evaluate hepatic and thyroid gland transcriptomic changes, as well as hepatic UGT activity levels. At VPD dosages of 300 mg/kg/day and higher, 2-fold increases of serum thyroid stimulating hormone (TSH) levels were observed in male SD rats after 28 days of dosing, while serum thyroxine (T4) and triiodothyronine (T3) levels were unchanged. Liver UGT enzyme activity levels were increased in VPD-treated rats after 5 days. In addition, in the 5-day study, VPD caused increased hepatic mRNA levels of a panel of drug metabolizing enzymes (DMEs) and transporters, including Cyp3a1, Cyp2b1, Ugt 2b1, and Abcc3. Similar patterns of induction were observed in primary rat hepatocytes exposed to VPD. Transcriptomic changes in the thyroid gland were identified for genes involved in thyroid hormone biosynthesis and in the FAK, PTEN, and Wnt/β-catenin signaling pathways. Collectively, these data indicate that VPD acts as an inducer of hepatic DMEs in SD rats and that this likely leads to enhanced peripheral metabolism of T3/T4, resulting in a feedback response characterized by increased serum TSH levels, and thyroid gland hypertrophy and hyperplasia.
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http://dx.doi.org/10.1016/j.toxlet.2011.10.012DOI Listing
January 2012

Global transcriptomic profiling using small volumes of whole blood: a cost-effective method for translational genomic biomarker identification in small animals.

Int J Mol Sci 2011 13;12(4):2502-17. Epub 2011 Apr 13.

Global Pharmaceutical Research and Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, Il 60064, USA; E-Mails: (M.M.F.); (A.C.D.); (P.M.J.); (M.J.L.); (E.A.G.B.).

Blood is an ideal tissue for the identification of novel genomic biomarkers for toxicity or efficacy. However, using blood for transcriptomic profiling presents significant technical challenges due to the transcriptomic changes induced by ex vivo handling and the interference of highly abundant globin mRNA. Most whole blood RNA stabilization and isolation methods also require significant volumes of blood, limiting their effective use in small animal species, such as rodents. To overcome these challenges, a QIAzol-based RNA stabilization and isolation method (QSI) was developed to isolate sufficient amounts of high quality total RNA from 25 to 500 μL of rat whole blood. The method was compared to the standard PAXgene Blood RNA System using blood collected from rats exposed to saline or lipopolysaccharide (LPS). The QSI method yielded an average of 54 ng total RNA per μL of rat whole blood with an average RNA Integrity Number (RIN) of 9, a performance comparable with the standard PAXgene method. Total RNA samples were further processed using the NuGEN Ovation Whole Blood Solution system and cDNA was hybridized to Affymetrix Rat Genome 230 2.0 Arrays. The microarray QC parameters using RNA isolated with the QSI method were within the acceptable range for microarray analysis. The transcriptomic profiles were highly correlated with those using RNA isolated with the PAXgene method and were consistent with expected LPS-induced inflammatory responses. The present study demonstrated that the QSI method coupled with NuGEN Ovation Whole Blood Solution system is cost-effective and particularly suitable for transcriptomic profiling of minimal volumes of whole blood, typical of those obtained with small animal species.
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http://dx.doi.org/10.3390/ijms12042502DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3127131PMC
January 2015

Comparison of TNFα to lipopolysaccharide as an inflammagen to characterize the idiosyncratic hepatotoxicity potential of drugs: Trovafloxacin as an example.

Int J Mol Sci 2010 Nov 18;11(11):4697-714. Epub 2010 Nov 18.

Department of Cellular, Molecular, & Exploratory Toxicology, Abbott Laboratories; Abbott Park, IL 60064, USA; E-Mails: (A.C.D.); (J.F.W.); (E.A.G.B.).

Idiosyncratic drug reactions (IDRs) are poorly understood, unpredictable, and not detected in preclinical studies. Although the cause of these reactions is likely multi-factorial, one hypothesis is that an underlying inflammatory state lowers the tolerance to a xenobiotic. Previously used in an inflammation IDR model, bacterial lipopolysaccharide (LPS) is heterogeneous in nature, making development of standardized testing protocols difficult. Here, the use of rat tumor necrosis factor-α (TNFα) to replace LPS as an inflammatory stimulus was investigated. Sprague-Dawley rats were treated with separate preparations of LPS or TNFα, and hepatic transcriptomic effects were compared. TNFα showed enhanced consistency at the transcriptomic level compared to LPS. TNFα and LPS regulated similar biochemical pathways, although LPS was associated with more robust inflammatory signaling than TNFα. Rats were then codosed with TNFα and trovafloxacin (TVX), an IDR-associated drug, and evaluated by liver histopathology, clinical chemistry, and gene expression analysis. TNFα/TVX induced unique gene expression changes that clustered separately from TNFα/levofloxacin, a drug not associated with IDRs. TNFα/TVX cotreatment led to autoinduction of TNFα resulting in potentiation of underlying gene expression stress signals. Comparison of TNFα/TVX and LPS/TVX gene expression profiles revealed similarities in the regulation of biochemical pathways. In conclusion, TNFα could be used in lieu of LPS as an inflammatory stimulus in this model of IDRs.
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http://dx.doi.org/10.3390/ijms11114697DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3000109PMC
November 2010

Role of cytochrome P450c17α in dibromoacetic acid-induced testicular toxicity in rats.

Arch Toxicol 2011 May 3;85(5):513-23. Epub 2010 Nov 3.

Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, IL 60064, USA.

Dibromoacetic acid (DBAA), a by-product formed during disinfection of drinking water, alters spermatogenesis in rats through defective spermiation. The mechanism underlying this toxicity is not fully understood. In this study, gene expression data generated with microarrays from testes were used to generate a mechanistic understanding of DBAA-induced testicular toxicity. Testes were collected from male Sprague-Dawley rats dosed orally for 1 and 4 days with DBAA at 250 mg/kg/day. At both time points, DBAA administration induced delayed spermiation in Stage X tubules and regulated the expression of a small number of genes, including a mild but consistent downregulation of cytochrome P450c17α (CYP17) mRNA, an enzyme expressed by Leydig cells and essential for the production of testicular androgens. Downregulation of CYP17 was confirmed at the protein level and its biological significance was substantiated by demonstrating reduced testicular testosterone levels in DBAA-dosed rats. Furthermore, testosterone production by human chorionic gonadotrophin (hCG)-stimulated rat primary Leydig cells was reduced following treatment with 100 μM DBAA. Collectively, these results indicate that DBAA can directly target rat Leydig cells and downregulate testicular CYP17 expression with a resulting decreased testicular testosterone production. This disruption of testicular steroidogenesis is likely to contribute to the mechanism of failed spermiation observed in rats following exposure to DBAA.
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http://dx.doi.org/10.1007/s00204-010-0600-2DOI Listing
May 2011

In vitro micronucleus screening of pharmaceutical candidates by flow cytometry in Chinese hamster V79 cells.

Environ Mol Mutagen 2011 Jun 20;52(5):355-62. Epub 2010 Oct 20.

Abbott Laboratories, Illinois, USA.

We previously reported a high concordance of in vitro micronucleus (MNvit) results obtained by flow cytometry to the known cytogenetic activity often commercially available compounds mentioned as validation compounds in an early draft of the OECD MNvit TG487 [Bryce et al., 2010; Organization for Economic Co-operation and Development(OECD), 2007]. The current study investigated this method in Chinese hamster V79 cells with pharmaceutical compounds of unknown genotoxic potential. Twenty-five compounds from several therapeutic areas such as oncology, neuroscience and immunological research were tested in the flow cytometry assay, and for comparison using the cytokinesis-block microscopy assay. Five of these 25 compounds were considered positive for micronucleus induction by the microscopy assessment. In all cases, the results from the flow cytometry assess ment matched the results of the microscopy assay. Thus, flow cytometry is a viable method for assessing the aneugenic/clastogenic potential of pharmaceutical drug candidates. The flow method offered several advantages over traditional microscopy. For instance, the ratio of micronuclei (MN) to 10,000 nuclei was evaluated in less than 2 min vs.15 min to manually assess 600 binucleate cells. Evaluation by flow cytometry can be automated,freeing resources and eliminating scorer fatigue.The assay may also provide for mechanistic understanding of MN formation based on size and the ratio of nuclei with sub-2N DNA content, allowing for discrimination between aneugenic and clastogenic compounds.
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http://dx.doi.org/10.1002/em.20631DOI Listing
June 2011

Assessing renal function: some significant improvements on the horizon.

Authors:
Eric A G Blomme

Vet J 2011 May 23;188(2):128-9. Epub 2010 Aug 23.

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http://dx.doi.org/10.1016/j.tvjl.2010.07.014DOI Listing
May 2011

Liver transcriptomic changes associated with ritonavir-induced hyperlipidemia in sensitive and resistant strains of rats.

Vet J 2010 Jul 23;185(1):75-82. Epub 2010 May 23.

Abbott Laboratories, Abbott Park, IL, USA.

Ritonavir (RTV) and other protease inhibitors (PIs) used for the treatment of human immunodeficiency virus (HIV) infection are associated with elevated serum triglycerides (TG) and cholesterol in some patients. A rat strain (Sprague-Dawley or SD) commonly used in toxicology studies is not sensitive to RTV-induced hyperlipidemia, making mechanistic studies and the identification of novel, lipid-neutral PIs challenging. The objective of this study was to identify a rat strain that mirrors human PI-associated hyperlipidemia. RTV was administered at 100 mg/kg/day for 5 days to a panel of 14 rat strains estimated to cover approximately 86% of the known genetic variance in rats. Increased serum TG and cholesterol levels occurred only in two rat strains, including LEW x BN rats. Livers from LEW x BN (sensitive) and SD (resistant) rats were then evaluated using microarrays to investigate differences in the transcriptomic response to RTV. Several genes, including some involved in bile acid biosynthesis, gluconeogenesis, and carbohydrate metabolism, were differentially regulated between the two strains. In particular, cytochrome P450 7A1 (CYP7A1), a key enzyme for cholesterol metabolism, was down-regulated in the sensitive and up-regulated in resistant rats. Collectively, these results demonstrate the utility of a genetically diverse rat panel to identify strains with clinical relevance for a particular adverse effect. Furthermore, the genome-wide transcriptomic analysis suggests that RTV-induced hyperlipidemia is at least in part due to changes in hepatic lipid biosynthesis and metabolism. These findings will facilitate the discovery of novel, lipid-neutral HIV PIs and the identification of relevant biomarkers for this adverse event.
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http://dx.doi.org/10.1016/j.tvjl.2010.04.017DOI Listing
July 2010

Renal biomarker qualification submission: a dialog between the FDA-EMEA and Predictive Safety Testing Consortium.

Nat Biotechnol 2010 May 10;28(5):455-62. Epub 2010 May 10.

Novartis Pharma AG, Basel, Switzerland.

The first formal qualification of safety biomarkers for regulatory decision making marks a milestone in the application of biomarkers to drug development. Following submission of drug toxicity studies and analyses of biomarker performance to the Food and Drug Administration (FDA) and European Medicines Agency (EMEA) by the Predictive Safety Testing Consortium's (PSTC) Nephrotoxicity Working Group, seven renal safety biomarkers have been qualified for limited use in nonclinical and clinical drug development to help guide safety assessments. This was a pilot process, and the experience gained will both facilitate better understanding of how the qualification process will probably evolve and clarify the minimal requirements necessary to evaluate the performance of biomarkers of organ injury within specific contexts.
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http://dx.doi.org/10.1038/nbt.1625DOI Listing
May 2010

Theranostics in veterinary medicine: where are we heading?

Vet J 2010 Sep 1;185(3):237-8. Epub 2009 Nov 1.

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http://dx.doi.org/10.1016/j.tvjl.2009.09.021DOI Listing
September 2010