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Mutation Research. Reviews in Mutation... 2020An underappreciated aspect of human mutagenicity biomonitoring is tissue specificity reflected in different assays, especially those that measure events that can only... (Review)
Review
An underappreciated aspect of human mutagenicity biomonitoring is tissue specificity reflected in different assays, especially those that measure events that can only occur in developing bone marrow (BM) cells. Reviewed here are 9 currently-employed human mutagenicity biomonitoring assays. Several assays measure chromosome-level events in circulating T-lymphocytes (T-cells), i.e., traditional analyses of aberrations, translocation studies involving chromosome painting and fluorescence in situ hybridization (FISH) and determinations of micronuclei (MN). Other T-cell assays measure gene mutations. i.e., hypoxanthine-guanine phosphoriboslytransferase (HPRT) and phosphoribosylinositol glycan class A (PIGA). In addition to the T-cell assays, also reviewed are those assays that measure events in peripheral blood cells that necessarily arose in BM cells, i.e., MN in reticulocytes; glycophorin A (GPA) gene mutations in red blood cells (RBCs), and PIGA gene mutations in RBC or granulocytes. This review considers only cell culture- or cytometry-based assays to describe endpoints measured, methods, optimal sampling times, and sample summaries of typical quantitative and qualitative results. However, to achieve its intended focus on the target cells where events occur, kinetics of the cells of peripheral blood that derive at some point from precursor cells are reviewed to identify body sites and tissues where the genotoxic events originate. Kinetics indicate that in normal adults, measured events in T-cells afford global assessments of in vivo mutagenicity but are not specific for BM effects. Therefore, an agent's capacity for inducing mutations in BM cells cannot be reliably inferred from T-cell assays as the magnitude of effect in BM, if any, is unknown. By contrast, chromosome or gene level mutations measured in RBCs/reticulocytes or granulocytes must originate in BM cells, i.e. in RBC or granulocyte precursors, thereby making them specific indicators for effects in BM. Assays of mutations arising directly in BM cells may quantitatively reflect the mutagenicity of potential leukemogenic agents.
Topics: Adult; Bone Marrow; Chromosome Aberrations; Erythrocytes; Glycophorins; Humans; In Situ Hybridization, Fluorescence; Mutagenicity Tests; Mutation; Reticulocytes
PubMed: 33339577
DOI: 10.1016/j.mrrev.2020.108341 -
Chemico-biological Interactions Aug 2022In recent years concerns over consumer exposure to mineral oil aromatic hydrocarbons (MOAH), especially those containing alkylated polycyclic aromatic hydrocarbons...
In recent years concerns over consumer exposure to mineral oil aromatic hydrocarbons (MOAH), especially those containing alkylated polycyclic aromatic hydrocarbons (PAHs), have emerged. This is especially due to the fact that some PAHs are known to be genotoxic and carcinogenic upon metabolic activation. However, available toxicological data on PAHs mainly relate to non-substituted PAHs with limited data on alkyl substituted PAHs. Therefore, the aim of the present study was to characterize in more detail the effect of alkyl substitution on the metabolism and mutagenicity of benzo[a]pyrene (B[a]P), a PAH known to be genotoxic and carcinogenic. To this end, the oxidative metabolism and mutagenicity of B[a]P and a series of its alkyl substituted analogues were quantified using in vitro microsomal incubations and the Ames test. The results obtained reveal that upon alkylation the metabolic oxidation shifts to the aliphatic side chain at the expense of aromatic ring oxidation. The overall metabolism, including metabolism via aromatic ring oxidation resulting potentially in bioactivation, was substantially reduced with elongation of the alkyl side chain, with metabolism of B[a]P with an alkyl substituent of >6 C atoms being seriously hampered. In the Ames test upon metabolic activation, the methyl substitution of B[a]P resulted in an increase or decrease of the mutagenic potency depending on the substitution position. The relevant pathways for mutagenicity of the selected monomethyl substituted B[a]P may involve the formation of a 7,8-dihydrodiol-9,10-epoxide, a 4,5-oxide and/or a benzylic alcohol as an oxidative side chain metabolite which subsequently may give rise to an unstable and reactive sulfate ester conjugate. It is concluded that alkylation of B[a]P does not systematically reduce its mutagenicity in spite of the metabolic shift from aromatic to side chain oxidation.
Topics: Benzo(a)pyrene; Carcinogens; Mutagenesis; Mutagenicity Tests; Mutagens; Polycyclic Aromatic Hydrocarbons
PubMed: 35671827
DOI: 10.1016/j.cbi.2022.110007 -
Environmental Science & Technology May 2014With the growing number of new exhaust after-treatment systems, fuels and fuel additives for internal combustion engines, efficient and reliable methods for detecting... (Comparative Study)
Comparative Study
With the growing number of new exhaust after-treatment systems, fuels and fuel additives for internal combustion engines, efficient and reliable methods for detecting exhaust genotoxicity and mutagenicity are needed to avoid the widespread application of technologies with undesirable effects toward public health. In a commonly used approach, organic extracts of particulates rather than complete exhaust is used for genotoxicity/mutagenicity assessment, which may reduce the reliability of the results. In the present study, we assessed the mutagenicity and the genotoxicity of complete diesel exhaust compared to an organic exhaust particle extract from the same diesel exhaust in a bacterial and a eukaryotic system, that is, a complex human lung cell model. Both, complete exhaust and organic extract were found to act mutagenic/genotoxic, but the amplitudes of the effects differed considerably. Furthermore, our data indicate that the nature of the mutagenicity may not be identical for complete exhaust and particle extracts. Because in addition, differences between the responses of the different biological systems were found, we suggest that a comprehensive assessment of exhaust toxicity is preferably performed with complete exhaust and with biological systems representative for the organisms and organs of interest (i.e., human lungs) and not only with the Ames test.
Topics: DNA Damage; Gene Expression Profiling; Humans; Lung; Mutagenicity Tests; Mutagens; Particulate Matter; Reproducibility of Results; Salmonella typhimurium; Vehicle Emissions
PubMed: 24697289
DOI: 10.1021/es4056033 -
Genes & Genetic Systems Apr 2023Chromosomal damage occurs both endogenously and exogenously and is a crucial factor in the induction of carcinogenesis. Chemically induced chromosomal damage is mainly... (Review)
Review
Chromosomal damage occurs both endogenously and exogenously and is a crucial factor in the induction of carcinogenesis. Chemically induced chromosomal damage is mainly exogenous. The OECD has developed methods to detect chemicals that induce chromosomal damage so as to identify hazardous substances and limit their exposure to humans. The development and improvement of in vitro mammalian cell methods have been the focus of recent research, as these techniques have higher throughput than in vivo animal methods and are cruelty-free. In vitro mammalian cell methods are highly sensitive and widely used. Nevertheless, they have a high frequency of misleading positive test results, causing the wastage of vital raw materials and pharmaceutical agents, and necessitating additional in vivo animal tests. Therefore, the improvement of in vitro mammalian cell methods is required. Novel methodologies have been proposed and developed for robust animal-free evaluation. As they include omics and AI approaches that use big data, they may enable objective, multidirectional interpretation when applied in combination with current in vitro experimental techniques. We review the existing approaches toward improving chromosome damage detection and introduce innovative techniques that facilitate animal-free testing. The current and latest evaluation methods can support the protection of public health as well as the development of promising chemicals that enrich our lives.
Topics: Animals; Humans; Mutagenicity Tests; Public Health; Carcinogenesis; DNA Damage; Chromosomes; Mammals
PubMed: 36754383
DOI: 10.1266/ggs.22-00058 -
Mutation Research. Genetic Toxicology... Dec 2019The bacterial reverse mutation test is a mainstay for evaluation of mutagenicity predicting the carcinogenic potential of a test substance and is recommended by...
The bacterial reverse mutation test is a mainstay for evaluation of mutagenicity predicting the carcinogenic potential of a test substance and is recommended by regulatory agencies across the globe. The popularity of the test is due, in part, to the relatively low cost, rapid results and small amount of test material required compared to most other toxicological tests as well as the near universal acceptance of the toxicological significance of a clear positive or negative result. Most laboratories follow the Organization for Economic Cooperation and Development Test Guideline 471 (TG471) or national guidelines based on TG471. Regulatory agencies in most countries are obligated to consider results from tests which meet the recommendations laid out in TG471. Nonetheless, laboratories unfamiliar with the test sometimes have trouble generating reliable, reproducible results. TG471 is a test guideline, not a detailed test protocol. A group of experts from regulatory agencies and laboratories which use the assay has assembled here a set of recommendations which if followed, will allow an inexperienced laboratory to acquire proficiency in assay conduct. These include recommendations for how to create a cell bank for the 5 Salmonella typhimurium/Escherichia coli strains and develop a laboratory protocol to reliably culture each strain to ensure each culture has the characteristics which allow adequate sensitivity for detection of mutagens using the test as described in TG471. By testing compounds on the provided lists of positive and negative test substances, the laboratory will have surmounted many of the problems commonly encountered during routine testing of unknown chemicals and will have gained the experience necessary to prepare the detailed protocol needed for performing the test under Good Laboratory Procedures and the laboratory will have generated the historical positive and negative control databases which are needed for test reports which adhere to TG471.
Topics: Efficiency, Organizational; Escherichia coli; Laboratories; Mutagenicity Tests; Salmonella typhimurium
PubMed: 31708077
DOI: 10.1016/j.mrgentox.2019.07.005 -
Toxicology Letters Sep 2018Skin tumors have been observed in C3H/HeJ mice following treatment with high and strongly irritating concentrations of 2-ethylhexyl acrylate (2-EHA). Dermal... (Review)
Review
Skin tumors have been observed in C3H/HeJ mice following treatment with high and strongly irritating concentrations of 2-ethylhexyl acrylate (2-EHA). Dermal carcinogenicity studies performed with 2-EHA are reviewed, contrasting the results in two mouse strains (C3H/HeJ and NMRI) under different dosing regimens. Application of contemporary evaluation criteria to the existing dermal carcinogenicity dataset demonstrates that 2-EHA induces skin tumors only at concentrations exceeding an maximum tolerated dose (MTD) and in the immune-dysregulated C3H/HeJ mouse model. Overall, the available chronic toxicity and genotoxicity data on 2-EHA support a non-genotoxic chemical irritant mechanism, whereby chronic irritation leads to inflammation, tissue injury, and wound repair, the latter of which is disrupted in C3H/HeJ mice and leads to tumor formation. Tumor response information in excess of an MTD should not be considered in a human hazard or risk assessment paradigm. For the purposes of an appropriate hazard assessment, 2-EHA did not cause or initiate dermal carcinogenesis in an immune competent (NMRI) mouse model, and, even in the immune compromised C3H/HeJ model, did not induce skin tumors at doses which did not exceed the MTD.
Topics: Acrylates; Air Pollutants, Occupational; Animals; Carcinogenesis; Dose-Response Relationship, Drug; Guidelines as Topic; Humans; Immunocompromised Host; Maximum Tolerated Dose; Mutagenicity Tests; Reproducibility of Results; Risk Assessment; Skin; Skin Neoplasms; Species Specificity; Toxicity Tests, Acute; Toxicity Tests, Chronic
PubMed: 29775721
DOI: 10.1016/j.toxlet.2018.05.016 -
Mutation Research Feb 2011Isatin (1H-indole-2,3-dione) is a synthetically versatile substrate used for the synthesis of heterocyclic compounds and as a raw material for drug synthesis. Isatin and...
Isatin (1H-indole-2,3-dione) is a synthetically versatile substrate used for the synthesis of heterocyclic compounds and as a raw material for drug synthesis. Isatin and its derivatives demonstrate anticonvulsant, antibacterial, antifungal, antiviral, and anticancer properties. We evaluated the genotoxic and mutagenic effects of acute (24h) and repeated (14d) exposure to isatin in vivo, using the comet assay and the micronucleus test. Three doses (50, 100, and 150mg/kgb.w.) were administered to mice via gavage. Doses were selected according to the LD(50) of isatin, estimated in a preliminary test to be 1g/kgb.w. To evaluate the results, parametric (ANOVA/Tukey) and non-parametric (Kruskal-Wallis/Dunn's post hoc test) tests were used, according to the nature of the data distribution. At all doses (50, 100 and 150mg/kgb.w.), after acute treatment with isatin, alterations in DNA migration (comet assay) were not observed and mutagenic effects were not seen (micronucleus test on peripheral blood cells). After repeated doses, only the highest dose of isatin (150mg/kgb.w.) induced alterations in the DNA that gave rise to micronuclei in the bone marrow and peripheral blood cells of the mice. Our results show that the mutagenic and genotoxic effects of isatin depend on dose and on period of exposure.
Topics: Animals; Bone Marrow Cells; Comet Assay; DNA Damage; Dose-Response Relationship, Drug; Female; Isatin; Leukocytes; Male; Mice; Micronucleus Tests; Microscopy, Fluorescence; Mutagenicity Tests; Reticulocytes; Time Factors
PubMed: 21111845
DOI: 10.1016/j.mrgentox.2010.11.006 -
Journal of Food and Drug Analysis Mar 2014Titanium dioxide nanoparticles (TiO(2)-NPs, <100 nm) are increasingly being used in pharmaceuticals and cosmetics due to the unique properties derived from their small... (Review)
Review
Titanium dioxide nanoparticles (TiO(2)-NPs, <100 nm) are increasingly being used in pharmaceuticals and cosmetics due to the unique properties derived from their small sizes. However, their large surface-area to mass ratio and high redox potential may negatively impact human health and the environment. TiO(2)-NPs can cause inflammation, pulmonary damage, fibrosis, and lung tumors and they are possibly carcinogenic to humans. Because cancer is a disease involving mutation, there are a large number of studies on the genotoxicity of TiO(2)-NPs. In this article, we review the results that have been reported in the literature, with a focus on data generated from the standard genotoxicity assays. The data include genotoxicity results from the Ames test, in vitro and in vivo Comet assay, in vitro and in vivo micronucleus assay, sister chromatid exchange assay, mammalian cell hypoxanthine-guanine phosphoribosyl transferase gene assay, the wing somatic mutation and recombination assay, and the mouse phosphatidylinositol glycan, class A gene assay. Inconsistent results have been found in these assays, with both positive and negative responses being reported. The in vitro systems for assessing the genotoxicity of TiO(2)-NPs have generated a greater number of positive results than the in vivo systems, and tests for DNA and chromosome damage have produced more positive results than the assays measuring gene mutation. Nearly all tests for measuring the mutagenicity of TiO(2)-NPs were negative. The current data indicate that the genotoxicity of TiO(2)-NPs is mediated mainly through the generation of oxidative stress in cells.
Topics: Animals; DNA Damage; Humans; Metal Nanoparticles; Mutagenicity Tests; Titanium
PubMed: 24673907
DOI: 10.1016/j.jfda.2014.01.008 -
Food and Chemical Toxicology : An... Aug 2017The assessment of genotoxicity represents an essential component of the safety assessment of all types of substances. Several in vitro tests are available at different... (Review)
Review
The assessment of genotoxicity represents an essential component of the safety assessment of all types of substances. Several in vitro tests are available at different stages of development and acceptance, yet they are not considered at present sufficient to fully replace animal tests needed to evaluate the safety of substances. For an overall improvement of the traditional genotoxicity testing paradigm, several recent activities have taken place. These include the improvement of existing tests, the development of novel tests, as well as, the establishment and exploration of approaches to optimise in vitro testing accuracy. Furthermore, useful tools, such as databases or reference chemical lists have been developed to support advances in this field.
Topics: Animals; DNA; DNA Damage; Humans; Mutagenicity Tests; Mutagens
PubMed: 27554597
DOI: 10.1016/j.fct.2016.08.024 -
The Journal of Toxicological Sciences Dec 2009Mutagenicity of fucoxanthinol (FXOH), the major compound after oral ingestion of fucoxanthin (FX), was evaluated by in vitro Ames test, and of FX by in vivo micronucleus...
Mutagenicity of fucoxanthinol (FXOH), the major compound after oral ingestion of fucoxanthin (FX), was evaluated by in vitro Ames test, and of FX by in vivo micronucleus test. In in vitro Ames test, bacterial reverse mutation was examined by using Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537, and Escherichia coli WP2uvrA/pKM101, with or without metabolic activation by S9 mix in the preincubation method, and mutagenicity of FXOH was found to be negative in all cases. In in vivo micronucleus test, mice were orally administered with FX at doses of 500, 1,000 and 2,000 mg/kg, and the bone marrow cells were taken 24 hr after the administration to observe the incidence of micronucleus cells, and mutagenicity of FX was found to be negative at all doses. Based on the data of the present study it can be presumed that orally administered FX is a safe compound in terms of mutagenicity under the experimental conditions employed here.
Topics: Administration, Oral; Animals; Female; In Vitro Techniques; Male; Mice; Mice, Inbred ICR; Micronucleus Tests; Mutagenicity Tests; Rats; Rats, Sprague-Dawley; Undaria; Xanthophylls; beta Carotene
PubMed: 19952505
DOI: 10.2131/jts.34.693