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Lechleiter J, Hellmiss R, Duerson K, Ennulat D, David N, Clapham D, Peralta E. Distinct sequence elements control the specificity of G protein activation by muscarinic acetylcholine receptor subtypes. EMBO J 1990; 9:4381-90. [PMID: 2124972 PMCID: PMC552228 DOI: 10.1002/j.1460-2075.1990.tb07888.x] [Citation(s) in RCA: 140] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Relatively little is understood concerning the mechanisms by which subtypes of receptors, G proteins and effector enzymes interact to transduce specific signals. Through expression of normal, hybrid and deletion mutant receptors in Xenopus oocytes, we determined the G protein coupling characteristics of the functionally distinct m2 and m3 muscarinic acetylcholine receptor (mAChR) subtypes and identified the critical receptor sequences responsible for G protein specificity. Activation of a pertussis toxin insensitive G protein pathway, leading to a rapid and transient release of intracellular Ca2+ characteristic of the m3 receptor, could be specified by the transfer of as few as nine amino acids from the m3 to the m2 receptor. In a reciprocal manner, transfer of no more than 21 residues from the m2 to the m3 receptor was sufficient to specify activation of a pertussis toxin sensitive G protein coupled to a slow and oscillatory Ca2+ release pathway typical of the m2 subtype. Notably, these critical residues occur within the same region of the third cytoplasmic domain of functionally distinct mAChR subtypes.
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140 |
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Boone L, Meyer D, Cusick P, Ennulat D, Bolliger AP, Everds N, Meador V, Elliott G, Honor D, Bounous D, Jordan H. Selection and interpretation of clinical pathology indicators of hepatic injury in preclinical studies. Vet Clin Pathol 2005; 34:182-8. [PMID: 16134065 DOI: 10.1111/j.1939-165x.2005.tb00041.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This position paper delineates the expert recommendations of the Regulatory Affairs Committee of the American Society for Veterinary Clinical Pathology for the use of preclinical, clinical pathology endpoints in assessment of the potential for drug-induced hepatic injury in animals and humans. Development of these guidelines has been based on current recommendations in the relevant preclinical and human clinical trial literature; they are intended to provide a method for consistent and rigorous interpretation of liver-specific data for the identification of hepatic injury in preclinical studies and potential liability for hepatic injury in human patients.
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130 |
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Harpur E, Ennulat D, Hoffman D, Betton G, Gautier JC, Riefke B, Bounous D, Schuster K, Beushausen S, Guffroy M, Shaw M, Lock E, Pettit S. Biological Qualification of Biomarkers of Chemical-Induced Renal Toxicity in Two Strains of Male Rat. Toxicol Sci 2011; 122:235-52. [DOI: 10.1093/toxsci/kfr112] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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14 |
99 |
4
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Haley P, Perry R, Ennulat D, Frame S, Johnson C, Lapointe JM, Nyska A, Snyder P, Walker D, Walter G. STP position paper: best practice guideline for the routine pathology evaluation of the immune system. Toxicol Pathol 2005; 33:404-7; discussion 408. [PMID: 15805080 DOI: 10.1080/01926230590934304] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Practice Guideline |
20 |
97 |
5
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Gautier JC, Riefke B, Walter J, Kurth P, Mylecraine L, Guilpin V, Barlow N, Gury T, Hoffman D, Ennulat D, Schuster K, Harpur E, Pettit S. Evaluation of Novel Biomarkers of Nephrotoxicity in Two Strains of Rat Treated with Cisplatin. Toxicol Pathol 2010; 38:943-56. [DOI: 10.1177/0192623310379139] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Cisplatin is an anticancer agent that induces renal proximal tubule lesions in many species. Studies were conducted in Sprague-Dawley and Han-Wistar rats to evaluate the utility of novel preclinical biomarkers of nephrotoxicity for renal lesions caused by this compound. Groups of 10 males of each strain were given a single intraperitoneal injection of 0.3, 1, or 3 mg/kg cisplatin and were sacrificed on days 2, 3, and 5. The novel biomarkers α-glutathione-S-transferase (α-GST) (for proximal tubular injury), μ-glutathione-S-transferase (μ-GST) (for distal tubular injury), clusterin (for general kidney injury), and renal papillary antigen-1 (RPA-1) (for collecting duct injury) were measured in urine by enzyme immunoassay. Histologically, degeneration and necrosis of the S3 segment of the renal proximal tubule were observed on day 2 (Han-Wistar) and days 3 and 5 (both strains) at 1 and 3 mg/kg. Results showed that in both strains of rats, urinary α-GST and clusterin can be detected in urine soon after injury, are more sensitive than BUN and serum creatinine, and therefore are usable as noninvasive biomarkers of proximal tubule injury. Changes in both μ-GST or RPA-1 were considered to represent secondary minor effects of proximal tubular injury on distal segments of the nephron.
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71 |
6
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Ennulat D, Walker D, Clemo F, Magid-Slav M, Ledieu D, Graham M, Botts S, Boone L. Effects of Hepatic Drug-metabolizing Enzyme Induction on Clinical Pathology Parameters in Animals and Man. Toxicol Pathol 2010; 38:810-28. [DOI: 10.1177/0192623310374332] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hepatic drug-metabolizing enzyme (DME) induction is an adaptive response associated with changes in preclinical species; this response can include increases in liver weight, hepatocellular hyperplasia and hypertrophy, and upregulated tissue expression of DMEs. Effects of DME induction on clinical pathology markers of hepatobiliary injury and function in animals as well as humans are not well established. This component of a multipart review of the comparative pathology of xenobiotically mediated induction of hepatic metabolizing enzymes reviews pertinent data from retrospective and prospective preclinical and clinical studies. Particular attention is given to studies with confirmation of DME induction and concurrent evaluation of liver and/or serum hepatobiliary marker enzyme activities and histopathology. These results collectively indicate that in the rat, when histologic findings are limited to hepatocellular hypertrophy, DME induction is not expected to be associated with consistent or substantive changes in serum or plasma activity of hepatobiliary marker enzymes such as alanine aminotransferase, alkaline phosphatase, and gamma glutamyltransferase. In the dog and the monkey, published studies also do not demonstrate a consistent relationship across DME-inducing agents and changes in these clinical pathology parameters. However, increased liver alkaline phosphatase or gamma glutamyltransferase activity in dogs treated with phenobarbital or corticosteroids suggests that direct or indirect induction of select hepatobiliary injury markers can occur both in the absence of liver injury and independently of induction of DME activity. Although correlations between tissue and serum levels of these hepatobiliary markers are limited and inconsistent, increases in serum/plasma activities that are substantial or involve changes in other markers generally reflect hepatobiliary insult rather than DME induction. Extrahepatic effects, including disruption of the hypothalamic-pituitary-thyroid axis, can also occur as a direct outcome of hepatic DME induction in humans and animals. Importantly, hepatic DME induction and associated changes in preclinical species are not necessarily predictive of the occurrence, magnitude, or enzyme induction profile in humans.
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Ennulat D, Magid-Slav M, Rehm S, Tatsuoka KS. Diagnostic performance of traditional hepatobiliary biomarkers of drug-induced liver injury in the rat. Toxicol Sci 2010; 116:397-412. [PMID: 20466777 DOI: 10.1093/toxsci/kfq144] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Nonclinical studies provide the opportunity to anchor biochemical with morphologic findings; however, liver injury is often complex and heterogeneous, confounding the ability to relate biochemical changes with specific patterns of injury. The aim of the current study was to compare diagnostic performance of hepatobiliary markers for specific manifestations of drug-induced liver injury in rat using data collected in a recent hepatic toxicogenomics initiative in which rats (n = 3205) were given 182 different treatments for 4 or 14 days. Diagnostic accuracy of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (Tbili), serum bile acids (SBA), alkaline phosphatase (ALP), gamma glutamyl transferase (GGT), total cholesterol (Chol), and triglycerides (Trig) was evaluated for specific types of liver histopathology by Receiver Operating Characteristic (ROC) analysis. To assess the relationship between biochemical and morphologic changes in the absence of hepatocellular necrosis, a second ROC analysis was performed on a subset of rats (n = 2504) given treatments (n = 152) that did not cause hepatocellular necrosis. In the initial analysis, ALT, AST, Tbili, and SBA had the greatest diagnostic utility for manifestations of hepatocellular necrosis and biliary injury, with comparable magnitude of area under the ROC curve and serum hepatobiliary marker changes for both. In the absence of hepatocellular necrosis, ALT increases were observed with biochemical or morphologic evidence of cholestasis. In both analyses, diagnostic utility of ALP and GGT for biliary injury was limited; however, ALP had modest diagnostic value for peroxisome proliferation, and ALT, AST, and total Chol had moderate diagnostic utility for phospholipidosis. None of the eight markers evaluated had diagnostic value for manifestations of hypertrophy, cytoplasmic rarefaction, inflammation, or lipidosis.
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Research Support, Non-U.S. Gov't |
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Gore ER, Gower J, Kurali E, Sui JL, Bynum J, Ennulat D, Herzyk DJ. Primary antibody response to keyhole limpet hemocyanin in rat as a model for immunotoxicity evaluation. Toxicology 2004; 197:23-35. [PMID: 15003331 DOI: 10.1016/j.tox.2003.12.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2003] [Accepted: 12/04/2003] [Indexed: 11/17/2022]
Abstract
To address current regulatory expectations on immunotoxicity testing of new chemicals, we describe an animal model that measures the primary antibody response to the T-cell dependent antigen, keyhole limpet hemocyanin (KLH). Single immunization with KLH by either footpad (300microg/rat) or intravenous (300microg/kg) route in Sprague Dawley rats resulted in increased germinal center formation in the spleen and a robust anti-KLH IgM (70-388microg/ml) and IgG (230-470microg/ml) antibody response with peak detection on Days 5 and 14 post-immunization, respectively. Subcutaneous immunization with KLH (300microg/kg) resulted in a much weaker anti-KLH IgM and IgG (< or =20microg/ml) antibody response with no detectable increase in splenic germinal center formation. The utility of a rat KLH immunization model in detecting immunosuppression was evaluated with the known immunosuppressive drugs: cyclosporin, azathioprine and prednisolone. Rats, treated with drug at a maximum tolerated dose, were immunized with KLH by footpad or intravenous injection and serum samples were collected at various intervals up to 2 weeks post-immunization. Additional study parameters included terminal body weight, hematology and/or histopathology. All three drugs inhibited the IgM (60%) and IgG (> or =90%) antibody responses in the absence of overt toxicity based on evaluation of the standard toxicology parameters. In conclusion, measurement of a rat primary antibody response to KLH by ELISA is a reliable and readily standardized method for assessing immunotoxicity of pharmaceuticals.
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Gilmartin AG, Groy A, Gore ER, Atkins C, Long ER, Montoute MN, Wu Z, Halsey W, McNulty DE, Ennulat D, Rueda L, Pappalardi MB, Kruger RG, McCabe MT, Raoof A, Butlin R, Stowell A, Cockerill M, Waddell I, Ogilvie D, Luengo J, Jordan A, Benowitz AB. In vitro and in vivo induction of fetal hemoglobin with a reversible and selective DNMT1 inhibitor. Haematologica 2021; 106:1979-1987. [PMID: 32586904 PMCID: PMC8252945 DOI: 10.3324/haematol.2020.248658] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 06/18/2020] [Indexed: 12/20/2022] Open
Abstract
Pharmacological induction of fetal hemoglobin (HbF) expression is an effective therapeutic strategy for the management of beta-hemoglobinopathies such as sickle cell disease. DNA methyltransferase (DNMT) inhibitors 5-azacytidine (5-aza) and 5-aza-2'-deoxycytidine (decitabine) have been shown to induce fetal hemoglobin expression in both preclinical models and clinical studies, but are not currently approved for the management of hemoglobinopathies. We report here the discovery of a novel class of orally bioavailable DNMT1-selective inhibitors as exemplified by GSK3482364. This molecule potently inhibits the methyltransferase activity of DNMT1, but not DNMT family members DNMT3A or DNMT3B. In contrast with cytidine analog DNMT inhibitors, the DNMT1 inhibitory mechanism of GSK3482364 does not require DNA incorporation and is reversible. In cultured human erythroid progenitor cells (EPCs), GSK3482364 decreased overall DNA methylation resulting in de-repression of the gamma globin genes HBG1 and HBG2 and increased HbF expression. In a transgenic mouse model of sickle cell disease, orally administered GSK3482364 caused significant increases in both HbF levels and in the percentage HbF-expressing erythrocytes, with good overall tolerability. We conclude that in these preclinical models, selective, reversible inhibition of DNMT1 is sufficient for the induction of HbF, and is well-tolerated. We anticipate that GSK3482364 will be a useful tool molecule for the further study of selective DNMT1 inhibition both in vitro and in vivo.
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research-article |
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41 |
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Burkhardt JE, Pandher K, Solter PF, Troth SP, Boyce RW, Zabka TS, Ennulat D. Recommendations for the evaluation of pathology data in nonclinical safety biomarker qualification studies. Toxicol Pathol 2012; 39:1129-37. [PMID: 22116771 DOI: 10.1177/0192623311422082] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A set of best practices for the conduct of histopathology evaluation in nonclinical safety studies was endorsed by the Society of Toxicologic Pathology (STP) in 2004. These best practices indicate that the study pathologist should have knowledge of the treatment group and access to all available study-related data for the animal from which the tissue was obtained. A new set of best practices for the conduct of histopathology review for safety biomarker qualification for nonclinical studies has been endorsed by the STP and is summarized in this document. These best practices are generally similar to those for nonclinical safety studies, specifically that the pathologist be "unblinded" or have access to study data. Although histopathology evaluation in biomarker qualification studies must be performed without knowledge of novel biomarker data, the study pathologist(s) should be involved in the attendant meta-analyses of these data. Blinded evaluation is an experimental tool in biomarker qualification studies that is appropriate only when well-defined criteria for specific histopathologic findings are identified prior to blinded review. Additionally, this paper also considers the management of bias, the use of a tiered evaluation approach, the importance of using qualified pathologists and standard reporting, and the management of spontaneous findings.
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Journal Article |
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27 |
11
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Phillips JA, Holder DJ, Ennulat D, Gautier JC, Sauer JM, Yang Y, McDuffie E, Sonee M, Gu YZ, Troth SP, Lynch K, Hamlin D, Peters DG, Brees D, Walker EG. Rat Urinary Osteopontin and Neutrophil Gelatinase-Associated Lipocalin Improve Certainty of Detecting Drug-Induced Kidney Injury. Toxicol Sci 2016; 151:214-23. [DOI: 10.1093/toxsci/kfw038] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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Ennulat D, Adler S. Recent Successes in the Identification, Development, and Qualification of Translational Biomarkers. Toxicol Pathol 2014; 43:62-9. [DOI: 10.1177/0192623314554840] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The development of novel safety or efficacy biomarkers has increasingly been used to improve safety monitoring and minimize attrition during drug development; however, for new biomarkers, the failure rate can equal or exceed that of new chemical entities. Drug-induced kidney injury is recognized to occur throughout the drug development process, with histopathology considered to be the gold standard for preclinical toxicologic screening. Renal biomarkers used clinically are primarily biomarkers of renal function and are considered insensitive for the detection of drug-induced kidney injury during first-in-man studies, particularly for compounds known to induce renal injury in preclinical species. Recent efforts by public–private partnerships have led to unprecedented success in the identification, development, and qualification of several new translatable biomarkers of kidney injury in the rat. To optimize the chance of success in current and future biomarker efforts in preclinical species and man, selection and development of biomarkers should emphasize biological considerations including marker variability and biology in both health and disease. The research to support the qualification of novel renal safety markers for routine use in the clinical setting is currently underway, and results from this work are greatly anticipated.
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Van Biervliet J, de Lahunta A, Ennulat D, Oglesbee M, Summers B. Acquired cervical scoliosis in six horses associated with dorsal grey column chronic myelitis. Equine Vet J 2010; 36:86-92. [PMID: 14756379 DOI: 10.2746/0425164044864624] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Obert LA, Elmore SA, Ennulat D, Frazier KS. A Review of Specific Biomarkers of Chronic Renal Injury and Their Potential Application in Nonclinical Safety Assessment Studies. Toxicol Pathol 2021; 49:996-1023. [PMID: 33576319 DOI: 10.1177/0192623320985045] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A host of novel renal biomarkers have been developed over the past few decades which have enhanced monitoring of renal disease and drug-induced kidney injury in both preclinical studies and in humans. Since chronic kidney disease (CKD) and acute kidney injury (AKI) share similar underlying mechanisms and the tubulointerstitial compartment has a functional role in the progression of CKD, urinary biomarkers of AKI may provide predictive information in chronic renal disease. Numerous studies have explored whether the recent AKI biomarkers could improve upon the standard clinical biomarkers, estimated glomerular filtration rate (eGFR), and urinary albumin to creatinine ratio, for predicting outcomes in CKD patients. This review is an introduction to alternative assays that can be utilized in chronic (>3 months duration) nonclinical safety studies to provide information on renal dysfunction and to demonstrate specific situations where these assays could be utilized in nonclinical drug development. Novel biomarkers such as symmetrical dimethyl arginine, dickkopf homolog 3, and cystatin C predict chronic renal injury in animals, act as surrogates for GFR, and may predict changes in GFR in patients over time, ultimately providing a bridge from preclinical to clinical renal monitoring.
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Review |
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24 |
15
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Case Reports |
27 |
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Betton GR, Ennulat D, Hoffman D, Gautier JC, Harpur E, Pettit S. Biomarkers of Collecting Duct Injury in Han-Wistar and Sprague-Dawley Rats Treated with N-Phenylanthranilic Acid. Toxicol Pathol 2012; 40:682-94. [DOI: 10.1177/0192623311436174] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
N-phenylanthranilic acid is a chloride channel blocker that causes renal papillary necrosis in rats. Studies were conducted in two strains of male rats to evaluate novel biomarkers of nephrotoxicity. Han-Wistar rats were given daily oral doses of 50, 350, or up to 700 mg/kg/day of NPAA, and Sprague-Dawley rats were given 50 or 400 mg/kg/day of NPAA. Rats were euthanized on days 8 and 15. The candidate kidney injury biomarkers renal papillary antigen-1 (RPA-1, for collecting duct injury), clusterin (for general kidney injury), α-glutathione-S-transferase (a proximal tubular marker), and µ-glutathione-S-transferase (a distal tubular marker) were measured in urine by enzyme immunoassay. Characteristic degeneration and necrosis of the collecting duct and renal papilla were observed in Han-Wistar rats at the high dose on day 8 and at the mid and high doses on day 15, and in Sprague-Dawley rats given the high dose on days 8 and 15. Increases in urinary RPA-1, and to a lesser extent urine clusterin, were generally associated with the presence of collecting duct injury and were more sensitive than BUN and serum creatinine. On the other hand, decreases in α-glutathione-S-transferase without proximal tubule lesions in both strains and decreases in µ-glutathione-S-transferase in Sprague-Dawley rats only were not associated with morphological proximal or distal tubule abnormalities, so both were of less utility. It was concluded that RPA-1 is a new biomarker with utility in the detection of collecting duct injury in papillary necrosis in male rats.
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Bassage LH, Habecker PL, Russell EA, Ennulat D. Colic in a horse associated with a massive cystic duplication of the ascending colon. Equine Vet J 2000; 32:565-8. [PMID: 11093634 DOI: 10.2746/042516400777584677] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Case Reports |
25 |
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18
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Hailey JR, Nold JB, Brown RH, Cullen JM, Holder JC, Jordan HL, Ennulat D, Miller RT. Biliary Proliferative Lesions in the Sprague-Dawley Rat. Toxicol Pathol 2013; 42:844-54. [DOI: 10.1177/0192623313499976] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Whether biliary proliferative lesions in nonclinical species are predictive of potential hepatotoxicity in humans depends, at least in part, on the nature and severity of such changes in the nonclinical species. We reviewed published literature (clinical and nonclinical) and experimental data from rat toxicology studies conducted by GlaxoSmithKline and the National Institute of Environmental Health Sciences’ National Toxicology Program in an effort to better characterize the relative risk of hepatobiliary effects in humans. Available evidence supports the interpretation that minimal “typical” appearing bile duct hyperplasia limited to the portal triads may be considered non-adverse in the rat and is of little to no concern to humans. The toxicological relevance of mild to moderate “typical” hyperplasia is less certain, and may be considered adverse in the rat and potentially pose a risk for humans, particularly if accompanied by evidence of hepatobiliary injury or functional compromise. In addition, any proliferative lesion that includes atypical or dysplastic epithelial changes, oval cell proliferation, and/or significant extension beyond the portal tracts is considered more ominous and may be considered adverse in the rat.
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Burkhardt JE, Ennulat D, Pandher K, Solter PF, Troth SP, Boyce RW, Zabka TS. Topic of histopathology blinding in nonclinical safety biomarker qualification studies. Toxicol Pathol 2010; 38:666-7. [PMID: 20530250 DOI: 10.1177/0192623310371221] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Letter |
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Ramaiah L, Hinrichs MJ, Skuba EV, Iverson WO, Ennulat D. Interpreting and Integrating Clinical and Anatomic Pathology Results. Toxicol Pathol 2016; 45:223-237. [DOI: 10.1177/0192623316677068] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The continuing education course on integrating clinical and anatomical pathology data was designed to communicate the importance of using a weight of evidence approach to interpret safety findings in toxicology studies. This approach is necessary, as neither clinical nor anatomic pathology data can be relied upon in isolation to fully understand the relationship between study findings and the test article. Basic principles for correlating anatomic pathology and clinical pathology findings and for integrating these with other study end points were reviewed. To highlight these relationships, a series of case examples, presented jointly by a clinical pathologist and an anatomic pathologist, were used to illustrate the collaborative effort required between clinical and anatomical pathologists. In addition, the diagnostic utility of traditional liver biomarkers was discussed using results from a meta-analysis of rat hepatobiliary marker and histopathology data. This discussion also included examples of traditional and novel liver and renal biomarker data implementation in nonclinical toxicology studies to illustrate the relationship between discrete changes in biochemistry and tissue morphology.
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Ramaiah L, Tomlinson L, Tripathi NK, Cregar LC, Vitsky A, Beust BV, Barlow VG, Reagan WJ, Ennulat D. Principles for Assessing Adversity in Toxicologic Clinical Pathology. Toxicol Pathol 2017; 45:260-266. [DOI: 10.1177/0192623316681646] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
There is limited direction in the literature or regulatory guidance on determination of adversity for clinical pathology (CP) biomarkers in preclinical safety studies. Toxicologic clinical pathologists representing the American Society for Veterinary Clinical Pathology—Regulatory Affairs Committee and Society of Toxicologic Pathology—Clinical Pathology Interest Group identified principles, overall approach, and unique considerations for assessing adversity in CP data interpretation to provide a consensus opinion. Emphasized is the need for pathophysiologic context and a weight-of-evidence approach. Most CP biomarkers do not have the potential to be adverse in isolation, regardless of magnitude of change. Rather, they quantify or describe the impact of effects, provide adjunct or supportive information regarding a process or pathogenesis, and provide translational biomarkers of effect. Most often, CP changes are part of a constellation of findings that collectively are adverse. Thus, most CP changes must be interpreted in conjunction with other study findings and require contextual and integrative interpretation. Exceptions include critical CP changes without correlates that indicate a health risk in the tested species. Overall, CP changes should not be interpreted in isolation and their adversity is best addressed with an integrated approach.
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Tomlinson L, Ramaiah L, Tripathi NK, Barlow VG, Vitsky A, Poitout-Belissent FM, Bounous DI, Ennulat D. STP Best Practices for Evaluating Clinical Pathology in Pharmaceutical Recovery Studies. Toxicol Pathol 2016; 44:163-72. [DOI: 10.1177/0192623315624165] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The Society of Toxicologic Pathology formed a working group in collaboration with the American Society for Veterinary Clinical Pathology to provide recommendations for the appropriate inclusion of clinical pathology evaluation in recovery arms of nonclinical toxicity studies but not on when to perform recovery studies. Evaluation of the recovery of clinical pathology findings is not required routinely but provides useful information on risk assessment in nonclinical toxicity studies and is recommended when the ability of the organ to recover is uncertain. The study design generally requires inclusion of concurrent controls to separate procedure-related changes from test article–related changes, but return of clinical pathology values toward baseline may be sufficient in some cases. Evaluation of either a select or full panel of standard hematology, coagulation, and serum and urine chemistry biomarkers can be scientifically justified. It is also acceptable to redesignate dosing phase animals to the recovery phase or vice versa to optimize data interpretation. Assessment of delayed toxicity during the recovery phase is not required but may be appropriate in development programs with unique concerns. Evaluation of the recovery of clinical pathology data for vaccine development is required and, for efficacy markers, is recommended if it furthers pharmacologic understanding.
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Ennulat D, Ringenberg M, Frazier KS. Toxicologic Pathology Forum Opinion Paper*: Recommendations for a Tiered Approach to Nonclinical Mechanistic Nephrotoxicity Evaluation. Toxicol Pathol 2018; 46:636-646. [DOI: 10.1177/0192623318788302] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Nephrotoxicity is one of the more common causes of attrition in nonclinical drug development. Like most tissues, the kidney has a limited number of ways of responding to toxicological insults from diverse mechanistic pathways, which can limit the ability to determine mechanisms of renal injury using the assays routinely performed in preclinical toxicologic studies. In situations where the renal injury is unusual in morphology or if a therapeutic margin is low, additional investigative techniques may be needed to identify a potential mechanism of toxicity in order to inform clinical risk assessment or establish human relevance and translatability of the toxicity. While routine microscopic evaluation can suggest a specific pathogenesis, understanding the mechanism of renal injury often requires additional hypothesis-driven investigations and specialized techniques to obtain the data necessary to identify a nephrotoxic mechanism. Nonclinical mechanistic investigations can be resource-intensive and often yield limited new information. Although there are multiple avenues to investigate renal toxicity, no single mechanistic study or prescriptive battery of tests will identify the pathophysiologic basis for every potential mechanism of renal injury. To aid the nonclinical investigator, we outline a tiered approach for prioritizing investigations to provide a rational and linear road map for the exploration of mechanisms of drug-induced kidney injury. [Box: see text]
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Botts S, Ennulat D, Francke-Carroll S, Graham M, Maronpot RR, Mohutsky M. Introduction to Hepatic Drug Metabolizing Enzyme Induction in Drug Safety Evaluation Studies. Toxicol Pathol 2010; 38:796-8. [DOI: 10.1177/0192623310374330] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The following three articles represent the output of a combined effort initiated by the Scientific Regulatory Policy Committee of the Society of Toxicologic Pathology to provide a unified review of current scientific practices and relevant literature and provide suggestions regarding the recognition, interpretation, and risk assessment of hepatic drug metabolizing enzyme (DME) induction studies. The core objective was to provide a review that the scientific community including pathologists, regulatory scientists, toxicologists, investigative scientists, and others would find valuable for managing, designing, and interpreting toxicity studies supporting regulatory filings. Three working groups composed of scientists from industry, academia, and regulatory agencies were convened to review the available literature on important aspects of the interpretation and risk assessment of hepatic microsomal DME enzyme induction in three publications. The three reviews are as follows: “Effects of Hepatic Drug Metabolizing Enzyme Induction on Clinical Pathology Parameters in Animals and Man,” Toxicol Pathol “Hepatic Drug Metabolizing Enzyme Induction: Microscopic and Ultrastructural Appearance,” Toxicol Pathol “Hepatic Drug Metabolizing Enzyme Induction and Implications for Preclinical and Clinical Risk Assessment,” Toxicol Pathol The purpose of this introduction is not to summarize the articles but rather to frame the series and to provide a common mechanistic introduction.
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Cadilla R, Deaton DN, Do Y, Elkins PA, Ennulat D, Guss JH, Holt J, Jeune MR, King AG, Klapwijk JC, Kramer HF, Kramer NJ, Laffan SB, Masuria PI, McDougal AV, Mortenson PN, Musetti C, Peckham GE, Pietrak BL, Poole C, Price DJ, Rendina AR, Sati G, Saxty G, Shearer BG, Shewchuk LM, Sneddon HF, Stewart EL, Stuart JD, Thomas DN, Thomson SA, Ward P, Wilson JW, Xu T, Youngman MA. The exploration of aza-quinolines as hematopoietic prostaglandin D synthase (H-PGDS) inhibitors with low brain exposure. Bioorg Med Chem 2020; 28:115791. [PMID: 33059303 DOI: 10.1016/j.bmc.2020.115791] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 09/18/2020] [Accepted: 09/24/2020] [Indexed: 12/15/2022]
Abstract
GlaxoSmithKline and Astex Pharmaceuticals recently disclosed the discovery of the potent H-PGDS inhibitor GSK2894631A 1a (IC50 = 9.9 nM) as part of a fragment-based drug discovery collaboration with Astex Pharmaceuticals. This molecule exhibited good murine pharmacokinetics, allowing it to be utilized to explore H-PGDS pharmacology in vivo. Yet, with prolonged dosing at higher concentrations, 1a induced CNS toxicity. Looking to attenuate brain penetration in this series, aza-quinolines, were prepared with the intent of increasing polar surface area. Nitrogen substitutions at the 6- and 8-positions of the quinoline were discovered to be tolerated by the enzyme. Subsequent structure activity studies in these aza-quinoline scaffolds led to the identification of 1,8-naphthyridine 1y (IC50 = 9.4 nM) as a potent peripherally restricted H-PGDS inhibitor. Compound 1y is efficacious in four in vivo inflammatory models and exhibits no CNS toxicity.
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