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Lensen JFM, Hyttilä-Hopponen M, Karlsson S, Kuosmanen T, Lehtimäki J, Leino T. Characterization of Urothelial Inclusions in Male Wistar Han Rats Treated Orally With the Novel α2A-Adrenoceptor Agonist Tasipimidine. Toxicol Pathol 2021; 49:1232-1242. [PMID: 34238057 DOI: 10.1177/01926233211027471] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Intracellular inclusions were observed in urinary bladder epithelium of male Wistar rats, following oral treatment with high doses of the α2A-adrenoceptor agonist tasipimidine for 28 days. No cell death or inflammation was associated with the brightly eosinophilic inclusions. Electron microscopy (EM) studies showed that the inclusions represented intact or fragmented red blood cells (RBC) resulting from erythrophagocytosis, further supported by the presence of iron in urothelial cells. In addition, scattered iron-positive macrophages were observed in the submucosa and muscle layer, indicating microvascular leakage, as no major hemorrhage was evident. Despite the presence of inclusions, the urothelium showed normal uroplakin III distribution, normal cell turnover, and an absence of α-2u-globulin. It is, therefore, concluded that the inclusions were not associated with urothelial damage or increased renewal of the epithelium. This finding shows also that urothelial cells have the capability to phagocytize and break down RBCs originating from submucosal microvascular leakage. Similar changes were not observed in tasipimidine-treated beagle dogs (28 days), suggesting these findings were rat specific. The leakage of RBCs into the urothelium is suggested to be a consequence of exaggerated pharmacology leading to vasoconstriction of submucosal blood vessels in combination with transient increased bladder distension and pressure.
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Affiliation(s)
| | | | | | | | | | - Tiina Leino
- Orion Corporation, Orion Pharma, Espoo, Finland
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2
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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: 9] [Impact Index Per Article: 3.0] [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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Affiliation(s)
- Leslie A Obert
- 549350GlaxoSmithKline (GSK), Nonclinical Safety, Collegeville, PA, USA
| | - Susan A Elmore
- Cellular and Molecular Pathology Branch, National Toxicology Program (NTP), 6857National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Daniela Ennulat
- 549350GlaxoSmithKline (GSK), Nonclinical Safety, Collegeville, PA, USA
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3
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Tseng CH, Tseng FH. Peroxisome proliferator-activated receptor agonists and bladder cancer: lessons from animal studies. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, ENVIRONMENTAL CARCINOGENESIS & ECOTOXICOLOGY REVIEWS 2012; 30:368-402. [PMID: 23167631 DOI: 10.1080/10590501.2012.735519] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
This article reviews available animal studies on the possible link between the use of peroxisome proliferator-activated receptor (PPAR) agonists and bladder cancer, with further discussion on the possible implications to humans. Carcinogenicity studies suggest that the PPARγ agonist pioglitazone and dual PPARα/γ agonists such as ragaglitazar, muraglitazar, and naveglitazar may increase the risk of bladder cancer in a dose-responsive pattern in rats. It is interesting that bladder cancer related to PPAR agonists shows remarkable species- and sex-specificity and has a predilection to occur in the ventral dome of bladder in rodents. While male rats treated with pioglitazone or muraglitazar have a higher propensity to develop bladder cancer than female rats, mice of both sexes do not develop bladder cancer even when exposed to very high doses. Direct genotoxicity or cytotoxicity of PPAR agonists is unlikely to be the mode of action because most of the parent compounds or their metabolites of the PPAR agonists are neither mutagenic nor genotoxic, and they are rarely excreted in the urine; but a receptor-mediated PPAR effect cannot be excluded. Some suggest a "urolithiasis hypothesis" referring to the formation of urinary solids and calculi, which subsequently causes bladder necrosis, regenerative proliferation, hypertrophy, and cancer. However, whether these animal findings could have human relevance is not yet fully understood. Some argue that the urolithiasis-induced bladder cancer might be rat-specific and would probably not be applicable to humans. An effect of increased urinary growth factors induced by PPAR agonists has also been proposed, but this requires more investigations. Before fully clarified, a balance between the risks and benefits of the use of pioglitazone, an approved oral antidiabetic agent that has recently been linked to an increased but not yet confirmed risk of bladder cancer in humans, should be justified for individual use.
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Affiliation(s)
- Chin-Hsiao Tseng
- Department of Internal Medicine, National Taiwan University College of Medicine, Taipei, Taiwan.
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4
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Han ZZ, Koo KH, Kim KH, Bae JS, Shin SH, Kim HS, Kim JH, Heo HS, Gil KH, Lee JY, Kim KH, Kang BH, Lee HK, Choi HY, Li YC, Yeon SH, Lee JY, Song SW. Acute and 90-day subchronic toxicity studies of Silk peptide E5K6, in Sprague-Dawley rats. Food Chem Toxicol 2011; 49:2408-14. [PMID: 21729733 DOI: 10.1016/j.fct.2011.06.058] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 06/18/2011] [Accepted: 06/19/2011] [Indexed: 01/11/2023]
Abstract
Acute and 90-day subchronic oral toxicity studies of Silk peptide E5K6 were performed in Sprague-Dawley rats. In the acute toxicity study, Silk peptide E5K6 was administered orally to male and female rats at a single dose of 2000 and 5000 mg/kg. Mortality, clinical signs and body weight changes were monitored for 14 days. There were no treatment-related changes in these parameters. Therefore, the Approximate Lethal Dose (ALD) of Silk peptide E5K6 in male and female rats is higher than 5000 mg/kg. In the subchronic toxicity study, Silk peptide E5K6 was administered orally to male and female rats for 90 days at a single dose of 500, 1000, and 2000 mg/kg. There were no toxicologically significant changes in clinical signs, body weight, food and water consumptions, ophthalmoscopic examination, urinalysis, hematological and serum biochemical examinations, necropsy findings, organ weights and histopathological examination of all of the animals treated with Silk peptide E5K6. These results suggest that the oral No Observed Adverse-Effect Level (NOAEL) of Silk peptide E5K6 is greater than 2000 mg/kg/day in both sexes and the target organs were not established.
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Affiliation(s)
- Zhong-Ze Han
- Preclinical Research Center, ChemOn Inc., 334 Jeil-ri, Yangji-myeon, Cheoin-gu, Yongin-si, Gyeonggi-do 449-826, Republic of Korea
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5
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Sato K, Awasaki Y, Kandori H, Tanakamaru ZY, Nagai H, Baron D, Yamamoto M. Suppressive effects of acid-forming diet against the tumorigenic potential of pioglitazone hydrochloride in the urinary bladder of male rats. Toxicol Appl Pharmacol 2011; 251:234-44. [PMID: 21255596 DOI: 10.1016/j.taap.2011.01.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 01/06/2011] [Accepted: 01/07/2011] [Indexed: 10/18/2022]
Abstract
Pioglitazone hydrochloride (PIO), a peroxisome proliferator-activated receptor gamma (PPARγ) agonist, was administered orally for 85 weeks at 16 mg/kg/day to male rats fed either a diet containing 1.5% ammonium chloride (acid-forming diet) or a control diet to investigate the effects of urinary acidification induced by the acid-forming diet on the tumorigenic potential of PIO in the urinary bladder. The surviving animals at the end of the administration period were followed to the end of the 2-year study period without changes in the diet and were subjected to terminal necropsy on Week 104. The number of urinary microcrystals, evaluated by manual counting with light microscopy and by an objective method with a laser diffraction particle size analyzer, was increased by PIO on Weeks 12 and 25 and the increases were markedly suppressed by urinary acidification. Urinary citrate was decreased by PIO throughout the study period, but no changes were seen in urinary oxalate at any timepoint. The incidences of PIO-treated males bearing at least one of the advanced proliferative changes consisting of papillary hyperplasia, nodular hyperplasia, papilloma or carcinoma were significantly decreased from 11 of 82 males fed the control diet to 2 of 80 males fed the acid-forming diet. The acid-forming diet did not show any effects on the toxicokinetic parameters of PIO and its metabolites. Microcrystalluria appears to be involved in the development of the advanced stage proliferative lesions in bladder tumorigenesis induced by PIO in male rats.
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Affiliation(s)
- Keiichiro Sato
- Development Research Center, Takeda Pharmaceutical Company Limited, Osaka 532-8686, Japan.
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6
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Li Y, McLaren MC, McMartin KE. Involvement of urinary proteins in the rat strain difference in sensitivity to ethylene glycol-induced renal toxicity. Am J Physiol Renal Physiol 2010; 299:F605-15. [DOI: 10.1152/ajprenal.00419.2009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ethylene glycol (EG) exposure is a common model for kidney stones, because animals accumulate calcium oxalate monohydrate (COM) in kidneys. Wistar rats are more sensitive to EG than Fischer 344 (F344) rats, with greater COM deposition in kidneys. The mechanisms by which COM accumulates differently among strains are poorly understood. Urinary proteins inhibit COM adhesion to renal cells, which could alter COM deposition in kidneys. We hypothesize that COM accumulates more in Wistar rat kidneys because of lower levels of inhibitory proteins in urine. Wistar and F344 rats were treated with 0.75% EG in drinking water for 8 wk. Twenty-four-hour urine was collected every 2 wk for analysis of urinary proteins. Similar studies were conducted for 2 wk using 2% hydroxyproline (HP) as an alternative oxalate source. Total urinary protein was higher in F344 than Wistar rats at all times. Tamm-Horsfall protein was not different between strains. Osteopontin (OPN) levels in Wistar urine and kidney tissue were higher and were further increased by EG treatment. This increase in OPN occurred before renal COM accumulation. Untreated F344 rats showed greater CD45 and ED-1 staining in kidneys than untreated Wistars; in contrast, EG treatment increased CD45 and ED-1 staining in Wistars more than in F344 rats, indicating macrophage infiltration. This increase occurred in parallel with the increase in OPN and before COM accumulation. Like EG, HP induced markedly greater oxalate concentrations in the plasma and urine of Wistar rats compared with F344 rats. These results suggest that OPN upregulation and macrophage infiltration do not completely protect against COM accumulation and may be a response to crystal retention. Because the two oxalate precursors, EG and HP, produced similar elevations of oxalate, the strain difference in COM accumulation may result more so from metabolic differences between strains than from differences in urinary proteins or inflammatory responses.
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Affiliation(s)
- Yan Li
- Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, Louisiana
| | - Marie C. McLaren
- Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, Louisiana
| | - Kenneth E. McMartin
- Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, Louisiana
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7
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Tannehill-Gregg SH, Dominick MA, Reisinger AJ, Moehlenkamp JD, Waites CR, Stock DA, Sanderson TP, Cohen SM, Arnold LL, Schilling BE. Strain-related Differences in Urine Composition of Male Rats of Potential Relevance to Urolithiasis. Toxicol Pathol 2009; 37:293-305. [DOI: 10.1177/0192623309332990] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In carcinogenicity studies with PPAR γ and α/γ agonists, urinary bladder tumors have been reported in Harlan Sprague-Dawley (HSD) and Charles River Sprague-Dawley (SD) but not Wistar (WI) rats, with urolithiasis purported to be the inciting event. In two 3-month studies, the authors investigated strain-related differences in urine composition by sampling urine multiple times daily. Urine pH, electrolytes, creatinine, protein, citrate and oxalate levels, and serum citrate were assessed; urine sediment was analyzed by scanning electron microscopy and energy dispersive x-ray spectroscopy. HSD rats had significantly higher urine calcium than SD or WI rats, primarily as calcium phosphate-containing precipitate. When compared to SD rats, HSD rats had lower urine volume, higher urine protein, and a comparable (week 4) to lower (week 13) burden of MgNH4PO4 aggregates. Relative to WI rats, HSD rats had higher urine protein and magnesium and lower serum and urine citrate. Overall, the susceptibility to urolithiasis in male rats was HSD > SD > WI; this was likely due to strain-related differences in the amount of urine protein (a nidus for crystal formation), lithogenic ions, citrate (an inhibitor of lithogenesis), and/or volume. Strain-related differences in urine composition need to be considered when interpreting the outcome of studies with compounds that alter urine composition.
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Affiliation(s)
- Sarah H. Tannehill-Gregg
- Bristol-Myers Squibb Research & Development, Department of Drug Safety Evaluation, Mount Vernon, Indiana, USA
| | - Mark A. Dominick
- Bristol-Myers Squibb Research & Development, Department of Drug Safety Evaluation, Mount Vernon, Indiana, USA
| | - Amy J. Reisinger
- Bristol-Myers Squibb Research & Development, Department of Drug Safety Evaluation, Mount Vernon, Indiana, USA
| | - Jeffrey D. Moehlenkamp
- Bristol-Myers Squibb Research & Development, Department of Drug Safety Evaluation, Mount Vernon, Indiana, USA
| | - C. Robbie Waites
- Bristol-Myers Squibb Research & Development, Department of Drug Safety Evaluation, Mount Vernon, Indiana, USA
- SABIC Innovative Plastics, Mount Vernon, Indiana, USA
| | - David A. Stock
- Bristol-Myers Squibb Research & Development, Department of Global Biometric Sciences, Wallingford, Connecticut, USA
| | - Thomas P. Sanderson
- Bristol-Myers Squibb Research & Development, Department of Drug Safety Evaluation, Mount Vernon, Indiana, USA
| | - Samuel M. Cohen
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Lora L. Arnold
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Beth E. Schilling
- Bristol-Myers Squibb Research & Development, Department of Drug Safety Evaluation, Mount Vernon, Indiana, USA
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8
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Cohen SM, Ohnishi T, Clark NM, He J, Arnold LL. Investigations of rodent urinary bladder carcinogens: collection, processing, and evaluation of urine and bladders. Toxicol Pathol 2007; 35:337-47. [PMID: 17455081 DOI: 10.1080/01926230701197115] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Examination of the urine and the bladder epithelium are essential to the investigation of mechanisms of urinary bladder carcinogens in rodents. However, urine and bladder tissue specimens must be collected and processed properly if accurate data are to be derived. The optimum specimen for analysis of urinary constituents is fresh void urine collected from nonfasting animals. Fasting the animal prior to urine collection changes the normal composition, including pH. Many of the normal urinary constituents can influence the mode of action of bladder carcinogens, especially for non-genotoxic agents. Light microscopy is routinely used to examine the bladder epithelium. However, it is often necessary to use more sensitive techniques, such as scanning electron microscopy (SEM) to detect subtle cytotoxic changes in the superficial cell layer of the urothelium, and bromodeoxyuridine (BrdU) incorporation, PCNA, or Ki-67 immunohistochemistry to determine the labeling index for cell proliferation. The urinary bladder must be handled gently and inflated with fixative in situ before the animal dies to avoid artifactual autolytic damage to the bladder epithelium that is visible by SEM and may be mistaken for treatment-related changes. The purpose of this paper is to provide information for the proper collection and examination of urine and the urinary bladder.
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Affiliation(s)
- Samuel M Cohen
- Department of Pathology and Microbiology, and the Eppley Institute for Cancer Research, University of Nebraska Medical Center, Omaha, NE 68198-3135, USA.
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9
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Tannehill-Gregg SH, Sanderson TP, Minnema D, Voelker R, Ulland B, Cohen SM, Arnold LL, Schilling BE, Waites CR, Dominick MA. Rodent Carcinogenicity Profile of the Antidiabetic Dual PPAR α and γ Agonist Muraglitazar. Toxicol Sci 2007; 98:258-70. [PMID: 17426106 DOI: 10.1093/toxsci/kfm083] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The carcinogenic potential of muraglitazar, a dual human peroxisome proliferator-activated receptor alpha/gamma agonist, was evaluated in 2-year studies in mice (1, 5, 20, and 40 mg/kg) and rats (1, 5, 30, and 50 mg/kg). Benign gallbladder adenomas occurred at low incidences in male mice at 20 and 40 mg/kg (area under the curve [AUC] exposures > or = 62 times human exposure at 5 mg/day) and were considered drug related due to an increased incidence of gallbladder mucosal hyperplasia at these doses. There was a dose-related increased incidence of transitional cell papilloma and carcinoma of the urinary bladder in male rats at 5, 30, and 50 mg/kg (AUC exposures > or = 8 times human exposure at 5 mg/day). At 30 and 50 mg/kg, the urinary bladder tumors were accompanied by evidence of increased urine solids. Subsequent investigative studies established that the urinary bladder carcinogenic effect was mediated by urolithiasis rather than a direct pharmacologic effect on urothelium. Incidences of subcutaneous liposarcoma in male rats and subcutaneous lipoma in female rats were increased at 50 mg/kg (AUC exposures > or = 48 times human exposure at 5 mg/day) and attributed, in part, to persistent pharmacologic stimulation of preadipocytes. Toxicologically relevant nonneoplastic changes in target tissues included thinning of cortical bone in mice and hyperplastic and metaplastic adipocyte changes in mice and rats. Considering that muraglitazar is nongenotoxic, the observed tumorigenic effects in mice and rats have no established clinical relevance since they occurred at either clinically nonrelevant exposures (gallbladder and adipose tumors) or by a species-specific mechanism (urinary bladder tumors).
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Affiliation(s)
- Sarah H Tannehill-Gregg
- Bristol-Myers Squibb Pharmaceutical Research Institute, Department of Drug Safety Evaluation Mt. Vernon, Indiana 47721, USA.
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10
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Dominick MA, White MR, Sanderson TP, Van Vleet T, Cohen SM, Arnold LE, Cano M, Tannehill-Gregg S, Moehlenkamp JD, Waites CR, Schilling BE. Urothelial carcinogenesis in the urinary bladder of male rats treated with muraglitazar, a PPAR alpha/gamma agonist: Evidence for urolithiasis as the inciting event in the mode of action. Toxicol Pathol 2007; 34:903-20. [PMID: 17178691 DOI: 10.1080/01926230601072327] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Muraglitazar, a PPARalpha/gamma agonist, dose-dependently increased urinary bladder tumors in male Harlan Sprague-Dawley (HSD) rats administered 5, 30, or 50 mg/kg/day for up to 2 years. To determine the mode of tumor development, male HSD rats were treated daily for up to 21 months at doses of 0, 1, or 50 mg/kg while being fed either a normal or 1% NH4Cl-acidified diet. Muraglitazar-associated, time-dependent changes in urine composition, urothelial mitogenesis and apoptosis, and urothelial morphology were assessed. In control and treated rats fed a normal diet, urine pH was generally > or = 6.5, which facilitates formation of calcium-and magnesium-containing solids, particularly in the presence of other prolithogenic changes in rat urine. Urinary citrate, an inhibitor of lithogenesis, and soluble calcium concentrations were dose dependently decreased in association with increased calcium phosphate precipitate, crystals and/or microcalculi; magnesium ammonium phosphate crystals and aggregates; and calcium oxalate-containing thin, rod-like crystals. Morphologically, sustained urothelial cytotoxicity and proliferation with a ventral bladder predilection were noted in treated rats by month 1 and urinary carcinomas with a similar distribution occurred by month 9. Urothelial apoptotic rates were unaffected by muraglitazar treatment or diet. In muraglitazar-treated rats fed an acidified diet, urine pH was invariably < 6.5, which inhibited formation of calcium-and magnesium-containing solids. Moreover, dietary acidification prevented the urothelial cytotoxic, proliferative, and tumorigenic responses. Collectively, these data support an indirect pharmacologic mode of urinary bladder tumor development involving alterations in urine composition that predispose to urolithiasis and associated decreases in urine-soluble calcium concentrations.
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Affiliation(s)
- Mark A Dominick
- Department of Drug Safety Evaluation, Bristol-Myers Squibb Co., Evansville, Indiana 47721, USA.
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11
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Van Vleet TR, White MR, Sanderson TP, Cohen SM, Cano M, Arnold LL, Waites CR, Schilling BE, Mitroka J, Dominick MA. Subchronic Urinary Bladder Effects of Muraglitazar in Male Rats1. Toxicol Sci 2006; 96:58-71. [PMID: 17132713 DOI: 10.1093/toxsci/kfl176] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Muraglitazar, a PPARalpha/gamma dual agonist, was dosed orally to rats once daily for 13 weeks to evaluate urinary and urothelial changes of potential relevance to urinary bladder tumorigenesis. Groups of 17 young or aged rats per sex were fed a normal or 1% NH4Cl-supplemented diet and were dosed with 0, 1, or 50 mg/kg muraglitazar. Lithogenic ions and sediment were profiled from freshly voided urine samples collected 24 h after dosing, and drug exposures were measured. Urinary citrate, oxalate, and epidermal growth factor (EGF) were assayed from 18-h urine collections. Urothelium was assessed by light microscopy, scanning electron microscopy, and BrdU and TUNEL immunohistochemistry. When fed a normal diet, urine pH was higher in males (above 6.5). Urine volume/body weight was greater in females. Urine soluble/total calcium and magnesium and phosphorus/creatinine ratios were lower in male rats fed a normal diet. Urine citrate levels were decreased and oxalate was increased in young male rats treated with 50 mg/kg muraglitazar compared to age/sex/diet-matched controls. No changes in urine sediment were detected 24 h after dosing. In young male rats treated with 50 mg/kg on normal diet, multifocal urothelial necrosis and proliferation were observed, whereas urothelial apoptosis and urine EGF levels were unchanged compared to age/sex/diet-matched controls. Urothelial necrosis and proliferation were not correlated to systemic or urinary drug exposures and were prevented by dietary acidification. These data suggest that muraglitazar-associated changes in urine composition predispose to urothelial cytotoxicity and proliferation in the urinary bladder of young male rats and that urine sediment must be profiled at multiple daily timepoints to fully qualify drug-induced changes in urine composition.
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Affiliation(s)
- Terry R Van Vleet
- Departments of Drug Safety Evaluation, Bristol-Myers Squibb Company, Mt Vernon, Indiana 47721, USA
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12
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Cohen SM. Effects of PPARgamma and combined agonists on the urinary tract of rats and other species. Toxicol Sci 2005; 87:322-7. [PMID: 16049269 DOI: 10.1093/toxsci/kfi266] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Samuel M Cohen
- University of Nebraska Medical Center, Department of Pathology and Microbiology, Omaha, 68198-3135, USA.
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13
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Cohen SM, Johansson SL, Arnold LL, Lawson TA. Urinary tract calculi and thresholds in carcinogenesis. Food Chem Toxicol 2002; 40:793-9. [PMID: 11983274 DOI: 10.1016/s0278-6915(02)00020-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Numerous chemicals administered to rodents at relatively high doses produce urinary tract calculi, resulting in erosions or ulcerations of the urothelium, consequent regenerative hyperplasia, and ultimately tumors. This is a high-dose (threshold) phenomenon, which appears to occur more readily in rodents than in primates, including humans. Several anatomic and urinary physiologic differences between rodents and humans affect the quantitative extrapolation from results in rodent bioassays to human risk assessment. For most chemicals producing tumors by this mode of action, human exposures are significantly lower than would be expected to be required for production of calculi, and therefore pose no carcinogenic hazard to humans.
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Affiliation(s)
- S M Cohen
- Department of Pathology and Microbiology, University of Nebraska Medical Center, 983135 Nebraska Medical Center, Omaha, NE 68198-3135, USA.
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14
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Arnold LL, Cano M, St John MK, Healy CE, Cohen SM. Effect of sulfosulfuron on the urine and urothelium of male rats. Toxicol Pathol 2001; 29:344-52. [PMID: 11444256 DOI: 10.1080/019262301316905309] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Sulfosulfuron, developed as a herbicide, caused increased microcrystalluria and the formation of urinary tract calculi when fed to male and female rats in a chronic 2-year study at doses of 5,000 ppm and 20,000 ppm. Hyperplasia was also seen in urinary bladders at 5,000 ppm and 20,000 ppm, almost exclusively in the presence of observable calculi/microcalculi. Urinary bladder tumors were found in 2 females in the 5000 ppm group, both in the presence of calculi. No increased microcrystalluria, calculi, or tumors were found at doses of 500 ppm and lower. In the current study, 5 groups of male Sprague-Dawley rats were fed sulfosulfuron at doses of 50, 500, 5,000, and 20,000 ppm for 10 weeks. Ten animals were co-administered 5,000 ppm sulfosulfuron with 12,300 ppm NH4Cl to determine if inhibition of the formation of calculi would prevent any urothelial effects of treatment with sulfosulfuron. Ten animals in the control group and in the high-dose sulfosulfuron group were fed only basal diet for an additional 10 weeks to determine if the effects of sulfosulfuron on the bladder epithelium were reversible. There was an increased incidence of microcrystalluria observed at 5,000 and 20,000 ppm. There was no increase in microcrystalluria observed in the urine of rats co-administered sulfosulfuron and NH4Cl. Urinary bladder calculi were found in the bladder of 1 animal fed 20,000 ppm. Examination by light microscopy showed diffuse papillary/nodular hyperplasia of the bladder epithelium in this animal. No increased microcrystalluria was observed after withdrawal of the chemical from the diet and the bladder epithelium was normal by light microscopy. The hyperplastic effects associated with the feeding of high doses of sulfosulfuron occur only with the appearance of urinary tract calculi. Based on these results and anatomical differences between rats and humans, it may be concluded that the hyperplastic and carcinogenic effects of sulfosulfuron in rats are high-dose, threshold phenomena that are not likely to occur in humans under environmentally relevant exposures.
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Affiliation(s)
- L L Arnold
- Department of Pathology/Microbiology and the Eppley Cancer Center, University of Nebraska Medical Center, Omaha 68198-3135, USA
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Cohen SM, Arnold LL, Cano M, Ito M, Garland EM, Shaw RA. Calcium phosphate-containing precipitate and the carcinogenicity of sodium salts in rats. Carcinogenesis 2000; 21:783-92. [PMID: 10753216 DOI: 10.1093/carcin/21.4.783] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Sodium saccharin, ascorbate and other sodium salts fed at high doses to rats produce urinary bladder urothelial cytotoxicity with consequent regenerative hyperplasia. For sodium salts that have been tested, tumor activity is enhanced when administered either alone or after a brief exposure to a known genotoxic bladder carcinogen. These sodium salts alter urinary composition of rats resulting in formation of an amorphous precipitate. We examined the precipitate to ascertain its composition and further delineate the basis for its formation in rat urine. Using scanning electron microscopy with attached X-ray energy dispersive spectroscopy, the principal elements present were calcium, phosphorus, minor amounts of silicon and sulfur. Smaller elements are not detectable by this method. Infrared analyses demonstrated that calcium phosphate was in the tribasic form and silicon was most likely in the form of silica. Small amounts of saccharin were present in the precipitate from rats fed sodium saccharin (<5%), but ascorbate was not detectable in the precipitate from rats fed similar doses of sodium ascorbate. Large amounts of urea and mucopolysaccharide, apparently chondroitin sulfate, were detected in the precipitate by infrared analysis. Chemical analyses confirmed the presence of large amounts of calcium phosphate with variably small amounts of magnesium, possibly present as magnesium ammonium phosphate crystals, present in urine even in controls. Small amounts of protein, including albumin and alpha(2u)-globulin, were also detected (<5% of the precipitate). Calcium phosphate is an essential ingredient of the medium for tissue culture of epithelial cells, but when present at high concentrations (>5 mM) it precipitates and becomes cytotoxic. The nature of the precipitate reflects the unique composition of rat urine and helps to explain the basis for the species specificity of the cytotoxic and proliferative effects of high doses of these sodium salts.
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Affiliation(s)
- S M Cohen
- Department of Pathology and Microbiology, The Eppley Institute for Research on Cancer, University of Nebraska Medical Center, Omaha, Nebraska 68198-3135, USA.
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Li W, Wanibuchi H, Salim EI, Yamamoto S, Yoshida K, Endo G, Fukushima S. Promotion of NCI-Black-Reiter male rat bladder carcinogenesis by dimethylarsinic acid an organic arsenic compound. Cancer Lett 1998; 134:29-36. [PMID: 10381127 DOI: 10.1016/s0304-3835(98)00237-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Dimethylarsinic acid (DMAA) is a major metabolite of inorganic arsenicals in mammals. In the present study, we investigated its promoting effects on urinary bladder carcinogenesis in NCI-Black-Reiter (NBR) rats, which lack alpha2u-globulin synthesizing ability. Male 9-14-week-old NBR rats were treated sequentially with 0.05% N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) for 4 weeks and then given 100 ppm DMAA in their drinking water (group 1) for 32 weeks. Induction of preneoplastic lesions (papillary or nodular hyperplasia) in this DMAA-treated group was significantly increased as compared to the carcinogen alone control group (P < 0.01). The development of carcinomas was also enhanced and a significant increase in the 5-bromo-2'-deoxyuridine (BrdU) labeling index of the urinary bladder epithelial cells was observed for the DMAA treatment group. These results indicate that DMAA has promoting effects on urinary bladder carcinogenesis even in NBR rats, so its effects are not dependent on the presence of alpha2u-globulin.
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Affiliation(s)
- W Li
- First Department of Pathology, Osaka City University Medical School, Osaka, Japan
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Takayama S, Sieber SM, Adamson RH, Thorgeirsson UP, Dalgard DW, Arnold LL, Cano M, Eklund S, Cohen SM. Long-term feeding of sodium saccharin to nonhuman primates: implications for urinary tract cancer. J Natl Cancer Inst 1998; 90:19-25. [PMID: 9428778 DOI: 10.1093/jnci/90.1.19] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND It was observed in the early 1970s that saccharin produced bladder cancer in rats. However, it has been unclear whether sodium saccharin when consumed by humans poses a substantial carcinogenic hazard. Numerous epidemiologic studies have not shown any evidence of increased urothelial proliferation associated with ingestion of sodium saccharin. PURPOSE Our purpose was to determine the effects of long-term feeding of sodium saccharin to three species of nonhuman primates. METHODS Twenty monkeys of three species (six African green, seven rhesus, six cynomolgus, and one hybrid [of rhesus male and cynomolgus female parentage]) were treated with sodium saccharin (25 mg in the diet/kg body weight daily for 5 days a week) beginning within 24 hours after birth and continuing for up to 24 years. Sixteen monkeys (seven rhesus and nine cynomolgus) served as controls. During their last 2 years of life, urine was collected from selected treated and control animals and evaluated for various urinary chemistries and for the presence of calculi, microcrystalluria, and precipitate. Urinary bladders were examined by light microscopy and by scanning electron microscopy. RESULTS Sodium saccharin treatment had no effect on the urine or urothelium in any of these monkeys. There was no evidence of increased urothelial cell proliferation, and there was no evidence of formation of solid material in the urine. CONCLUSION Although the dose of sodium saccharin administered to these monkeys was only five to 10 times the allowable daily intake for humans, the results provide additional evidence that sodium saccharin is without a carcinogenic effect on the primate urinary tract.
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Affiliation(s)
- S Takayama
- Division of Basic Sciences, National Cancer Institute, Bethesda, MD 20892, USA
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Abstract
Urinary bladder carcinogenesis in rodents bears numerous similarities to the diseases in humans. In rats, the process progresses through the morphologic stages of simple hyperplasia, papillary and nodular hyperplasia, papilloma, noninvasive, and invasive carcinoma. In mice, the pathogenesis can be similar or can follow a sequence of marked dysplasia with or without hyperplasia, leading to carcinoma in situ and ultimately to high-grade invasive carcinoma. Although the papillary and nonpapillary diseases appear to be related in rodents and in humans, they are distinct morphologically, biologically, and molecularly. Numerous classes of genotoxic chemicals have been identified as bladder carcinogens in rodents, and some of these have also been identified as carcinogenic in humans, most notably, aromatic amines, nitrosamines, and cyclophosphamide. In contrast, nongenotoxic chemicals appear to be highly specific with respect to species, strain, diet, agent, dose, and mechanism. For some, it is unclear whether the results at high doses in rodents can be extrapolated to low doses or to humans, e.g., chemicals that cause bladder cancer only at high doses related to the formation of calculi. Numerous observations in rodents can assist in identifying possible mechanisms involved for these nongenotoxic chemicals and therefore can be important for a rational evaluation of human risk.
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Affiliation(s)
- S M Cohen
- University of Nebraska Medical Center, Department of Pathology and Microbiology, Omaha 68198-3135, USA
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Cohen SM, Masui T, Garland EM, Arnold LL. Effects of diet on urinary bladder carcinogenesis and cancer prevention. J Nutr 1997; 127:826S-829S. [PMID: 9164246 DOI: 10.1093/jn/127.5.826s] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Urine plays a major role in bladder carcinogenesis, acting as a transport mechanism for carcinogens, containing several growth factors stimulating cell proliferation, and indirectly affecting chemicals by alterations in concentrations of normal urinary components such as electrolytes, water and proteins. These latter effects are greatly modified by diet composition and consumption and also by water consumption. Several examples of these effects are presented.
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Affiliation(s)
- S M Cohen
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha
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Murai T, Mori S, Hosono M, Takashima A, Machino S, Oohara T, Yamashita H, Makino S, Matsuda T, Wanibuchi H, Fukushima S. Strain differences in sensitivity to the promoting effect of sodium L-ascorbate in a two-stage rat urinary bladder carcinogenesis model. Jpn J Cancer Res 1997; 88:245-53. [PMID: 9140108 PMCID: PMC5921381 DOI: 10.1111/j.1349-7006.1997.tb00374.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Rat strain differences in sensitivity to the promoting effect of sodium L-ascorbate (SA) on the development of urinary bladder tumors were investigated. In experiment 1, WS/Shi (WS), ODS/Shiod/od (ODS), and LEW/Crj (LEW) rats were initiated with 0.05% N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) in their drinking water and subsequently given basal Oriental MF diet (M) with or without a 5% SA supplement. In LEW rats the SA treatment increased the induction of neoplastic lesions in the urinary bladder, whereas WS and ODS animals proved unresponsive to its promoting effects. In experiment 2, WS and F344 rats were maintained on two kinds of commercial basal diets, M and CLEA CA-1 (C), during administration of SA, since dietary factors can influence promoting effects. Feeding M during the promotion period in F344 rats yielded significantly more neoplastic lesions than feeding C, but in WS rats no such dietary influence was apparent. In experiment 3, strain differences in biosynthesis of alpha-2u-globulin (alpha 1a-g) were assessed because both alpha 2a-g in the urine and administration of sodium salts of organic acids such as SA have been reported to be involved in tumor promotion. Immunohistochemical analysis of renal tubules and Western blotting analysis of urine revealed the presence of alpha 2a-g in all three strains examined. These data suggest that differences in susceptibility to promotion are due to genetic factors rather than dietary factors and the ability to synthesize alpha 2a-g.
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Affiliation(s)
- T Murai
- First Department of Pathology, Osaka City University Medical School
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