1
|
Toxicological and Nutraceutical Screening Assays of Some Artificial Sweeteners. Processes (Basel) 2022. [DOI: 10.3390/pr10020410] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Artificial sweeteners are food additives worldwide used instead of fructose or glucose in many diet beverages. Furthermore, diet beverages intake has been increasing every year. Thus, some food agencies should regulate it based on toxicological studies. Debates and controversial results are demonstrated, and authority can revise its decision on the basis of new data reporting toxicological effects since cyclamate has been forbidden in some countries. Therefore, the aim of this study was to report new data about the toxicity of acesulfame-k, aspartame, and cyclamate, which are useful for authority agencies, determining the toxic potential and nutraceutical capabilities of these compounds. The toxicity, antitoxicity, genotoxicity, antigenotoxicity, and life expectancy assays were carried out in Drosophila as an in vivo model. In addition, in vitro HL-60 line cell was used to evaluate the chemopreventive activity determining the cytotoxic effect and the capability of producing DNA damage due to internucleosomal fragmentation or DNA strand breaks. Furthermore, the methylated status of these cancer cells treated with the tested compounds was assayed as a cancer therapy. Our results demonstrated that all tested compounds were neither toxic nor genotoxic, whereas these compounds resulted in antigenotoxic and cytotoxic substances, except for cyclamate. Aspartame showed antitoxic effects in Drosophila. All tested compounds decreased the quality of life of this in vivo organism model. Acesulfame-k, aspartame, and cyclamate induced DNA damage in the HL-60 cell line in the comet assay, and acesulfame-k generally increased the methylation status. In conclusion, all tested artificial sweeteners were safe compounds at assayed concentrations since toxicity and genotoxicity were not significantly induced in flies. Moreover, Aspartame and Cyclamate showed protective activity against a genotoxin in Drosophila Regarding nutraceutical potential, acesulfame-k and aspartame could be demonstrated to be chemopreventive due to the cytotoxicity activity shown by these compounds. According to DNA fragmentation and comet assays, a necrotic way could be the main mechanism of death cells induced by acesulfame-k and aspartame. Finally, Acesulfame-K hypermethylated repetitive elements, which are hypomethylated in cancer cells resulting in a benefit to humans.
Collapse
|
2
|
Gentry R, Thompson CM, Franzen A, Salley J, Albertini R, Lu K, Greene T. Using mechanistic information to support evidence integration and synthesis: a case study with inhaled formaldehyde and leukemia. Crit Rev Toxicol 2021; 50:885-918. [PMID: 33538218 DOI: 10.1080/10408444.2020.1854678] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Formaldehyde is one of the most comprehensively studied chemicals, with over 30 years of research focused on understanding the development of cancer following inhalation. The causal conclusions regarding the potential for leukemia are largely based on the epidemiological literature, with little consideration of cancer bioassays, dosimetry studies, and mechanistic research, which challenge the biological plausibility of the disease. Recent reanalyzes of the epidemiological literature have also raised significant questions related to the purported associations between formaldehyde and leukemia. Because of this, considerable scientific debate and uncertainty remain on whether there is a causal association between formaldehyde inhalation exposure and leukemia. Further complexity in evaluating this association is related to the endogenous production of formaldehyde. Multiple modes of action (MOA) have been postulated for the development of leukemia following formaldehyde inhalation that includes unsupported hypotheses of direct or indirect toxicity to the target cell population. Herein, the available evidence relevant to evaluating the postulated MOAs for leukemia following formaldehyde inhalation exposure is organized in the IPCS MOA Framework. The integration of all the available evidence clearly highlights the limited amount of data that support any of the postulated MOAs and demonstrates a significant amount of research supporting the null hypothesis that there is no causal association between formaldehyde inhalation exposure and leukemia. These analyses result in a lack of confidence in any of the postulated MOAs, increasing confidence in the conclusion that there is a lack of biological plausibility for a causal association between formaldehyde inhalation exposure and leukemia.
Collapse
Affiliation(s)
| | | | | | | | - Richard Albertini
- Independent Consultant, Emeritus Professor, University of Vermont, Burlington, Vermont, USA
| | - Kun Lu
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | | |
Collapse
|
3
|
Gürler M, Martz W, Taştekin B, Najafova T, Dettmeyer RB. Estimates of Non-Alcoholic Food-Derived Ethanol and Methanol Exposure in Human. J Anal Toxicol 2020; 46:bkaa198. [PMID: 33382066 DOI: 10.1093/jat/bkaa198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 11/02/2020] [Accepted: 12/30/2020] [Indexed: 11/14/2022] Open
Abstract
Food-derived alcohol is almost not in question due to its low concentration. Nevertheless, could it pose a problem for some risk groups and forensic cases? To answer this, we aimed to simultaneously evaluate ethanol and methanol ingredients of a variety of non-alcoholic foods in two different countries and estimate their possible health and forensic consequences. Alcohols in foods were analysed by headspace gas chromatography (HS-GC). Human average acute daily food consumptions and food-derived blood alcohol concentrations (BAC) were determined by using the data of the EFSA Nutrition Survey. Methanol and ethanol ingredients of similar foods varied between the two cities. Most foods produce higher methanol concentrations than the Maximum Allowable Dose Level (23 mg). Especially fruit juices lead to the critical level of ethanol for children (6.0 mg/kg bw). Based on the results, adult daily intake of selected food groups does not bear ethanol that exceeds the legal limit of BAC or the limit not allowed by the religious and does not lead to acute alcohol toxicity. But these low levels of ethanol and methanol consumed via non-alcoholic foods for life can raise the vulnerability to chronic health problems (cancer, liver cirrhosis, Alzheimer's disease, autism, ocular toxicity, alterations in fetal development), and may lead to positive ethanol metabolite results (e. g. Ethyl glucuronide) when a low cut-off level is used. Therefore, studies on the alcohol contents of various natural and processed non-alcoholic foods along with their effects on humans, and new regulations on labeling the food products and conscious food consumption are in particular importance. It would also be important to consider unintentional alcohol consumption via non-alcoholic foods in the evaluation of clinical and forensic cases.
Collapse
Affiliation(s)
- Mukaddes Gürler
- Department of Medical Biochemistry, and Alcohol and Substance Research Center, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Walter Martz
- Institute of Forensic Medicine, FB11 Medicine, Justus-Liebig-University, Giessen, Germany
| | - Burak Taştekin
- Department of Forensic Medicine, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Tahmina Najafova
- Department of Medical Biochemistry, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Reinhard B Dettmeyer
- Institute of Forensic Medicine, FB11 Medicine, Justus-Liebig-University, Giessen, Germany
| |
Collapse
|
4
|
Andersen ME, Gentry PR, Swenberg JA, Mundt KA, White KW, Thompson C, Bus J, Sherman JH, Greim H, Bolt H, Marsh GM, Checkoway H, Coggon D, Clewell HJ. Considerations for refining the risk assessment process for formaldehyde: Results from an interdisciplinary workshop. Regul Toxicol Pharmacol 2019; 106:210-223. [PMID: 31059732 DOI: 10.1016/j.yrtph.2019.04.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 04/17/2019] [Accepted: 04/21/2019] [Indexed: 01/06/2023]
Abstract
Anticipating the need to evaluate and integrate scientific evidence to inform new risk assessments or to update existing risk assessments, the Formaldehyde Panel of the American Chemistry Council (ACC), in collaboration with the University of North Carolina, convened a workshop: "Understanding Potential Human Health Cancer Risk - From Data Integration to Risk Evaluation" in October 2017. Twenty-four (24) invited-experts participated with expertise in epidemiology, toxicology, science integration and risk evaluation. Including members of the organizing committee, there were 29 participants. The meeting included eleven presentations encompassing an introduction and three sessions: (1) "integrating the formaldehyde science on nasal/nasopharyngeal carcinogenicity and potential for causality"; (2) "integrating the formaldehyde science on lymphohematopoietic cancer and potential for causality; and, (3) "formaldehyde research-data suitable for risk assessment". Here we describe key points from the presentations on epidemiology, toxicology and mechanistic studies that should inform decisions about the potential carcinogenicity of formaldehyde in humans and the discussions about approaches for structuring an integrated, comprehensive risk assessment for formaldehyde. We also note challenges expected when attempting to reconcile divergent results observed from research conducted within and across different scientific disciplines - especially toxicology and epidemiology - and in integrating diverse, multi-disciplinary mechanistic evidence.
Collapse
Affiliation(s)
- Melvin E Andersen
- ScitoVation LLC, 100 Capitola Drive, Drive 106, Durham, NC, 27713, USA.
| | | | - James A Swenberg
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
| | - Kenneth A Mundt
- Ramboll US Corporation, Amherst, MA (currently with Cardno Chemrisk, Boston, MA, USA
| | | | | | - James Bus
- Center for Toxicology and Mechanistic Biology, Exponent, Alexandria, VA, USA
| | | | | | - Hermann Bolt
- Leibniz Institute for Working Environment and Human Factors (IfADo), Dortmund, Germany
| | - Gary M Marsh
- Department of Biostatistics, Center for Occupational Biostatistics and Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Harvey Checkoway
- University of California, San Diego, Department of Family Medicine and Public Health, USA
| | - David Coggon
- MRC Lifecourse Epidemiology Unit, University of Southampton, United Kingdom
| | - Harvey J Clewell
- Ramboll US Corporation, 6 Davis Drive, Suite 13, Research Triangle Park, NC, 27709, USA
| |
Collapse
|
5
|
Shibui Y, Fujitani S, Iwata H, Lynch B, Roberts A. Histological analyses of the Ishii (1981) rat carcinogenicity study of aspartame and comparison with the Ramazzini Institute studies. Regul Toxicol Pharmacol 2019; 102:23-29. [DOI: 10.1016/j.yrtph.2018.12.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 12/14/2018] [Accepted: 12/15/2018] [Indexed: 10/27/2022]
|
6
|
Min YS, Choi H, Yoo CI, Ahn YS. Cancer mortality in Korean workers occupationally exposed to methanol: a cohort study. Int Arch Occup Environ Health 2018; 92:551-557. [PMID: 30535884 DOI: 10.1007/s00420-018-1389-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 11/24/2018] [Indexed: 11/24/2022]
Abstract
PURPOSE Recently, the international agency for research on cancer recommended that methanol should be recognized as a medium-priority, human cancer risk. Therefore, we performed an epidemiological study to evaluate the relationship between methanol exposure and the cancer mortality of Korean workers occupationally exposed to methanol. METHODS The study cohort was composed of methanol-exposed 25,218 male workers, data on whom were available from the Korea Occupational Safety and Health Agency; all participants underwent methanol-associated medical check-ups at least once between January 2000 and December 2004. The durations of methanol exposure were categorized as < 10, 10-20, and ≥ 20 years. Workplace methanol exposure levels for each worker were divided into three grades. We compared their standardized cancer mortality rates (SMRs) to those of the general population. Intra-cohort hazard ratios were estimated using a Cox's proportional hazards model. RESULTS We found no positive association between methanol exposure and cancer mortality. In terms of all cancer mortality, methanol-exposed workers exhibited significantly lower SMRs than the general population. In terms of other cancer mortality, no significant difference or trend was evident as a function of duration of methanol exposure. CONCLUSIONS Although we found no significant correlation between methanol exposure and cancer mortality, we believe the work is meaningful; this is the first, large-scale, human epidemiological study. The carcinogenic potential of methanol remains an open question, and studies with longer-term follow-up periods are needed.
Collapse
Affiliation(s)
- Young-Sun Min
- Department of Occupational and Environmental Medicine, Dongguk University Gyeongju Hospital, Gyeongju, South Korea
| | - Hongsuk Choi
- Department of Occupational and Environmental Medicine, Dongguk University Gyeongju Hospital, Gyeongju, South Korea
| | - Cheol-In Yoo
- Department of Occupational and Environmental Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, South Korea
| | - Yeon-Soon Ahn
- Department of Preventive Medicine, Institute Occupational and Environmental Medicine, Yonsei University Wonju College of Medicine, Wonju, South Korea.
| |
Collapse
|
7
|
Critical review of the current literature on the safety of sucralose. Food Chem Toxicol 2017; 106:324-355. [DOI: 10.1016/j.fct.2017.05.047] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 05/06/2017] [Accepted: 05/22/2017] [Indexed: 01/24/2023]
|
8
|
Albertini RJ, Kaden DA. Do chromosome changes in blood cells implicate formaldehyde as a leukemogen? Crit Rev Toxicol 2016; 47:145-184. [DOI: 10.1080/10408444.2016.1211987] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|
9
|
Bogen KT, Heilman JM. Reassessment of MTBE cancer potency considering modes of action for MTBE and its metabolites. Crit Rev Toxicol 2016; 45 Suppl 1:1-56. [PMID: 26414780 DOI: 10.3109/10408444.2015.1052367] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
A 1999 California state agency cancer potency (CP) evaluation of methyl tert-butyl ether (MTBE) assumed linear risk extrapolations from tumor data were plausible because of limited evidence that MTBE or its metabolites could damage DNA, and based such extrapolations on data from rat gavage and rat and mouse inhalation studies indicating elevated tumor rates in male rat kidney, male rat Leydig interstitial cells, and female rat leukemia/lymphomas. More recent data bearing on MTBE cancer potency include a rodent cancer bioassay of MTBE in drinking water; several new studies of MTBE genotoxicity; several similar evaluations of MTBE metabolites, formaldehyde, and tert-butyl alcohol or TBA; and updated evaluations of carcinogenic mode(s) of action (MOAs) of MTBE and MTBE metabolite's. The lymphoma/leukemia data used in the California assessment were recently declared unreliable by the U.S. Environmental Protection Agency (EPA). Updated characterizations of MTBE CP, and its uncertainty, are currently needed to address a variety of decision goals concerning historical and current MTBE contamination. To this end, an extensive review of data sets bearing on MTBE and metabolite genotoxicity, cytotoxicity, and tumorigenicity was applied to reassess MTBE CP and related uncertainty in view of MOA considerations. Adopting the traditional approach that cytotoxicity-driven cancer MOAs are inoperative at very low, non-cytotoxic dose levels, it was determined that MTBE most likely does not increase cancer risk unless chronic exposures induce target-tissue toxicity, including in sensitive individuals. However, the corresponding expected (or plausible upper bound) CP for MTBE conditional on a hypothetical linear (e.g., genotoxic) MOA was estimated to be ∼2 × 10(-5) (or 0.003) per mg MTBE per kg body weight per day for adults exposed chronically over a lifetime. Based on this conservative estimate of CP, if MTBE is carcinogenic to humans, it is among the weakest 10% of chemical carcinogens evaluated by EPA.
Collapse
|
10
|
Gift JS, Caldwell JC, Jinot J, Evans MV, Cote I, Vandenberg JJ. Scientific considerations for evaluating cancer bioassays conducted by the Ramazzini Institute. ENVIRONMENTAL HEALTH PERSPECTIVES 2013; 121:1253-63. [PMID: 24045135 PMCID: PMC3852791 DOI: 10.1289/ehp.1306661] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Accepted: 09/13/2013] [Indexed: 05/05/2023]
Abstract
BACKGROUND The Ramazzini Institute (RI) has completed nearly 400 cancer bioassays on > 200 compounds. The European Food Safety Authority (EFSA) and others have suggested that study design and protocol differences between the RI and other laboratories by may contribute to controversy regarding cancer hazard findings, principally findings on lymphoma/leukemia diagnoses. OBJECTIVE We aimed to evaluate RI study design, protocol differences, and accuracy of tumor diagnoses for their impact on carcinogenic hazard characterization. METHODS We analyzed the findings from a recent Pathology Working Group (PWG) review of RI procedures and tumor diagnoses, evaluated consistency of RI and other laboratory findings for chemicals identified by the RI as positive for lymphoma/leukemia, and examined evidence for a number of other issues raised regarding RI bioassays. The RI cancer bioassay design and protocols were evaluated in the context of relevant risk assessment guidance from international authorities. DISCUSSION Although the PWG identified close agreement with RI diagnoses for most tumor types, it did not find close agreement for lymphoma/leukemia of the respiratory tract or for neoplasms of the inner ear and cranium. Here we discuss a) the implications of the PWG findings, particularly lymphoma diagnostic issues; b) differences between RI studies and those from other laboratories that are relevant to evaluating RI cancer bioassays; and c) future work that may help resolve some concerns. CONCLUSIONS We concluded that a) issues related to respiratory tract infections have complicated diagnoses at that site (i.e., lymphoma/leukemia), as well as for neoplasms of the inner ear and cranium, and b) there is consistency and value in RI studies for identification of other chemical-related neoplasia.
Collapse
Affiliation(s)
- Jeffrey S Gift
- National Center for Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
| | | | | | | | | | | |
Collapse
|
11
|
Wang SP, Hu XX, Meng QW, Muhammad SA, Chen RR, Li F, Li GQ. The involvement of several enzymes in methanol detoxification in Drosophila melanogaster adults. Comp Biochem Physiol B Biochem Mol Biol 2013; 166:7-14. [DOI: 10.1016/j.cbpb.2013.05.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 05/30/2013] [Accepted: 05/31/2013] [Indexed: 12/15/2022]
|
12
|
Schernhammer ES, Bertrand KA, Birmann BM, Sampson L, Willett WC, Feskanich D. Consumption of artificial sweetener- and sugar-containing soda and risk of lymphoma and leukemia in men and women. Am J Clin Nutr 2012; 96:1419-28. [PMID: 23097267 PMCID: PMC3497928 DOI: 10.3945/ajcn.111.030833] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Despite safety reports of the artificial sweetener aspartame, health-related concerns remain. OBJECTIVE We prospectively evaluated whether the consumption of aspartame- and sugar-containing soda is associated with risk of hematopoetic cancers. DESIGN We repeatedly assessed diet in the Nurses' Health Study (NHS) and Health Professionals Follow-Up Study (HPFS). Over 22 y, we identified 1324 non-Hodgkin lymphomas (NHLs), 285 multiple myelomas, and 339 leukemias. We calculated incidence RRs and 95% CIs by using Cox proportional hazards models. RESULTS When the 2 cohorts were combined, there was no significant association between soda intake and risks of NHL and multiple myeloma. However, in men, ≥1 daily serving of diet soda increased risks of NHL (RR: 1.31; 95% CI: 1.01, 1.72) and multiple myeloma (RR: 2.02; 95% CI: 1.20, 3.40) in comparison with men who did not consume diet soda. We observed no increased risks of NHL and multiple myeloma in women. We also observed an unexpected elevated risk of NHL (RR: 1.66; 95% CI: 1.10, 2.51) with a higher consumption of regular, sugar-sweetened soda in men but not in women. In contrast, when sexes were analyzed separately with limited power, neither regular nor diet soda increased risk of leukemia but were associated with increased leukemia risk when data for men and women were combined (RR for consumption of ≥1 serving of diet soda/d when the 2 cohorts were pooled: 1.42; 95% CI: 1.00, 2.02). CONCLUSION Although our findings preserve the possibility of a detrimental effect of a constituent of diet soda, such as aspartame, on select cancers, the inconsistent sex effects and occurrence of an apparent cancer risk in individuals who consume regular soda do not permit the ruling out of chance as an explanation.
Collapse
Affiliation(s)
- Eva S Schernhammer
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
| | | | | | | | | | | |
Collapse
|
13
|
Wang SP, He GL, Chen RR, Li F, Li GQ. The involvement of cytochrome P450 monooxygenases in methanol elimination in Drosophila melanogaster larvae. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2012; 79:264-275. [PMID: 22508581 DOI: 10.1002/arch.21021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Methanol is one of the most common short-chain alcohols in fermenting fruits, the natural food of the fruit fly, Drosophila melanogaster. The larvae cope continuously with methanol at various concentrations in order to survive and develop. In the present article, we found toxicities of dietary methanol and formaldehyde were enhanced by piperonyl butoxide, but not by 3-amino-1, 2, 4-triazole, 4-methylpyrazole, diethylmeleate, and triphenyl phosphate, when assessing by the combination index method. These results reveal that cytochrome P450 monooxygenases (CYPs), rather than catalases, alcohol dehydrogenases, glutathione S-transferases, and esterases, participate in methanol metabolism. Moreover, methanol exposure dramatically increased CYP activity. The ratios of the CYP activities in treated larvae to those in control reached, respectively, up to 3.0-, 3.9-, and 2.7-fold, at methanol concentrations of 22.6, 27.9, and 34.5 mg/g diet. In addition, methanol exposure greatly up-regulated the mRNA expression level of five Cyp genes, which were Cyp304a1, Cyp9f2, Cyp28a5, Cyp4d2, and Cyp4e2. Their resulting proteins were suggested as the candidate enzymes for methanol metabolism in D. melanogaster larvae.
Collapse
Affiliation(s)
- Shu-Ping Wang
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | | | | | | | | |
Collapse
|
14
|
Scientific Opinion on the evaluation of the substances currently on the list in the Annex to Commission Directive 96/3/EC as acceptable previous cargoes for edible fats and oils - Part I of III. EFSA J 2011. [DOI: 10.2903/j.efsa.2011.2482] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
|
15
|
Lu K, Gul H, Upton PB, Moeller BC, Swenberg JA. Formation of hydroxymethyl DNA adducts in rats orally exposed to stable isotope labeled methanol. Toxicol Sci 2011; 126:28-38. [PMID: 22157354 DOI: 10.1093/toxsci/kfr328] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Methanol is a large volume industrial chemical and widely used solvent and fuel additive. Methanol's well known toxicity and use in a wide spectrum of applications has raised long-standing environmental issues over its safety, including its carcinogenicity. Methanol has not been listed as a carcinogen by any regulatory agency; however, there are debates about its carcinogenic potential. Formaldehyde, a metabolite of methanol, has been proposed to be responsible for the carcinogenesis of methanol. Formaldehyde is a known carcinogen and actively targets DNA and protein, causing diverse DNA and protein damage. However, formaldehyde-induced DNA adducts arising from the metabolism of methanol have not been reported previously, largely due to the absence of suitable DNA biomarkers and the inability to differentiate what was due to methanol compared with the substantial background of endogenous formaldehyde. Recently, we developed a unique approach combining highly sensitive liquid chromatography-mass spectrometry methods and exposure to stable isotope labeled chemicals to simultaneously quantify formaldehyde-specific endogenous and exogenous DNA adducts. In this study, rats were exposed daily to 500 or 2000 mg/kg [¹³CD₄]-methanol by gavage for 5 days. Our data demonstrate that labeled formaldehyde arising from [¹³CD₄]-methanol induced hydroxymethyl DNA adducts in multiple tissues in a dose-dependent manner. The results also demonstrated that the number of exogenous DNA adducts was lower than the number of endogenous hydroxymethyl DNA adducts in all tissues of rats administered 500 mg/kg per day for 5 days, a lethal dose to humans, even after incorporating an average factor of 4 for reduced metabolism due to isotope effects of deuterium-labeled methanol into account.
Collapse
Affiliation(s)
- Kun Lu
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | | | | | | | | |
Collapse
|
16
|
Bailey LA, Prueitt RL, Rhomberg LR. Hypothesis-Based Weight-of-Evidence evaluation of methanol as a human carcinogen. Regul Toxicol Pharmacol 2011; 62:278-91. [PMID: 22166730 DOI: 10.1016/j.yrtph.2011.11.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 11/09/2011] [Accepted: 11/28/2011] [Indexed: 02/07/2023]
Abstract
Recent scientific debate has focused on the potential for exposure to methanol to cause lymphomas in humans. The concern stems from a few animal studies reporting an association, although evidence suggests the studies may have been confounded by chronic respiratory infection. Although the toxicological evidence for methanol carcinogenesis is weak, two modes of action have been put forth, one involving metabolism of methanol to formaldehyde, followed by formaldehyde induction of lymphoma, and another involving oxidative stress caused by hydrogen peroxide release during catalase-induced metabolism of methanol to formaldehyde. In this article, we apply our Hypothesis-Based Weight-of-Evidence (HBWoE) approach to evaluate the evidence regarding methanol exposure and lymphoma, attending to how human, animal, and mode-of-action results inform one another, tracing the logic of inference within and across all studies, and articulating how one could account for the suite of available observations. Upon comparison of alternative proposals regarding what causal processes may have led to the array of observations as we see them, we conclude that the apparent association between methanol exposure and lymphoma in some animal studies is weak and strains biological plausibility, and is better interpreted as due to confounding or to a mechanism not relevant in humans.
Collapse
Affiliation(s)
- Lisa A Bailey
- Gradient, 20 University Road, Cambridge, MA 02138, USA.
| | | | | |
Collapse
|
17
|
|
18
|
Methanol exposure does not produce oxidatively damaged DNA in lung, liver or kidney of adult mice, rabbits or primates. Toxicol Appl Pharmacol 2011; 250:147-53. [DOI: 10.1016/j.taap.2010.10.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Revised: 09/02/2010] [Accepted: 10/05/2010] [Indexed: 12/20/2022]
|
19
|
Sweeting JN, Siu M, Wiley MJ, Wells PG. Species- and strain-dependent teratogenicity of methanol in rabbits and mice. Reprod Toxicol 2011; 31:50-8. [DOI: 10.1016/j.reprotox.2010.09.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 09/11/2010] [Accepted: 09/28/2010] [Indexed: 10/18/2022]
|
20
|
McCallum GP, Siu M, Ondovcik SL, Sweeting JN, Wells PG. Methanol exposure does not lead to accumulation of oxidative DNA damage in bone marrow and spleen of mice, rabbits or primates. Mol Carcinog 2010; 50:163-72. [DOI: 10.1002/mc.20701] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 10/08/2010] [Accepted: 10/12/2010] [Indexed: 12/12/2022]
|
21
|
Sweeting JN, Siu M, McCallum GP, Miller L, Wells PG. Species differences in methanol and formic acid pharmacokinetics in mice, rabbits and primates. Toxicol Appl Pharmacol 2010; 247:28-35. [PMID: 20510256 DOI: 10.1016/j.taap.2010.05.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 05/12/2010] [Accepted: 05/15/2010] [Indexed: 11/30/2022]
Abstract
Methanol (MeOH) is metabolized primarily by alcohol dehydrogenase in humans, but by catalase in rodents, with species variations in the pharmacokinetics of its formic acid (FA) metabolite. The teratogenic potential of MeOH in humans is unknown, and its teratogenicity in rodents may not accurately reflect human developmental risk due to differential species metabolism, as for some other teratogens. To determine if human MeOH metabolism might be better reflected in rabbits than rodents, the plasma pharmacokinetics of MeOH and FA were compared in male CD-1 mice, New Zealand white rabbits and cynomolgus monkeys over time (24, 48 and 6h, respectively) following a single intraperitoneal injection of 0.5 or 2g/kg MeOH or its saline vehicle. Following the high dose, MeOH exhibited saturated elimination kinetics in all 3 species, with similar peak concentrations and a 2.5-fold higher clearance in mice than rabbits. FA accumulation within 6h in primates was 5-fold and 43-fold higher than in rabbits and mice respectively, with accumulation being 10-fold higher in rabbits than mice. Over 48 h, FA accumulation was nearly 5-fold higher in rabbits than mice. Low-dose MeOH in mice and rabbits resulted in similarly saturated MeOH elimination in both species, but with approximately 2-fold higher clearance rates in mice. FA accumulation was 3.8-fold higher in rabbits than mice. Rabbits more closely than mice reflected primates for in vivo MeOH metabolism, and particularly FA accumulation, suggesting that developmental studies in rabbits may be useful for assessing potential human teratological risk.
Collapse
Affiliation(s)
- J Nicole Sweeting
- Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | | | | | | | | |
Collapse
|
22
|
Kimura N, Shimizu H, Eldawoody H, Nakayama T, Saito A, Tominaga T, Takahashi A. Effect of olmesartan and pravastatin on experimental cerebral aneurysms in rats. Brain Res 2010; 1322:144-52. [DOI: 10.1016/j.brainres.2010.01.044] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Revised: 01/16/2010] [Accepted: 01/20/2010] [Indexed: 12/30/2022]
|