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Biomonitoring of genotoxic effects for human exposure to nanomaterials: The challenge ahead
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Abstracts / Toxicology Letters 258S (2016) S2–S10
CEC 5: In vivo chemical genotoxin exposure and DNA damage in humans measured using the lymphocyte cytokinesis-block micronucleus (CBMN) assay CEC5-1 Pesticides and herbicides – Results of a systematic review of human exposure studies using the lymphocyte CBMN assay Claudia Bolognesi 1,∗ , Nina Holland 2 1
Environmental Carcinogenesis Unit, IRCCS AUO San Martino IST – National Cancer Research Institute, Genova, Italy 2 Nina Holland, School of Public Health, University of California, Berkeley, CA, USA Pesticides are widely used around the world, and hundreds of millions of people are exposed annually in occupational and environmental settings. Growing number of epidemiological and experimental studies indicate the occupational and environmental pesticide exposure as a contributing risk factor for cancer, neurodegenerative and neurodevelopmental disorders, respiratory diseases and diabetes. The pesticides exert their toxic effects through different modes of action related or not to their mechanism of action against “pest”. Experimental data revealed that many agrochemical active substances possess genotoxic properties. Assessment of genotoxicity of pesticides and biomonitoring their effects in exposed populations are critical for a better regulation and protection. A systematic review of the literature was carried out focusing on the application of the cytokinesis-block micronucleus assay in human lymphocytes (L-CBMN), a validated method for assessment of DNA damage induced by both clastogenic and aneuploidogenic mechanisms. A total of 55 full-text articles, related to 49 studies were retrieved including populations exposed to pesticides in different settings, such as chemical plant workers, pesticide sprayers, floriculturists, agricultural workers and nonoccupationally exposed groups. Majority of studies (36 out of 49) reported positive findings with L-CBMN assay. Subjects working in greenhouses or during intensive spraying season and having acute exposure, showed consistent increases in MN frequency. A decreased level of pesticide-induced genotoxicity was associated with the proper use of personal protection. Overall, this analysis confirmed that L-CBMN is an excellent tool for pesticide biomonitoring, and can validate the effects of educational and intervention programs on reducing exposure and genetic damage. http://dx.doi.org/10.1016/j.toxlet.2016.06.1085 CEC5-2 Heavy metals: Results of a systematic review of human exposure studies using the lymphocytes micronucleus assay Siegfried Knasmueller ∗ , Miroslav Miˇsík, Michael Kundi, Georg Wultsch, Armen Nersesyan Institute of Cancer Research, Department of Internal Medicine I, Medical University of Vienna, Vienna, Austria Millions of humans are exposed occupationally and environmentally to metals such as arsenic, cadmium, chromium, lead, mercury and vanadium. We evaluated the literature to find out if these metals act in humans as genotoxic carcinogens and if their effects can be detected in micronucleus assays with lymphocytes and in other genotoxicity assays. Numerous studies showed that arsenic, cadmium and chromium (VI) cause cancer and damage of
the genetic material via direct and indirect mechanisms including inhibition of DNA repair processes. Induction of DNA damage by these metals in exposed humans can be detected in MN assays with lymphocytes, i.e. almost all available studies yielded positive results. For vanadium only one human MN study has been published in which a positive effect was found; evidence for its carcinogenic properties is at present confined to data from animal experiments. For cadmium, there is an evidence that it causes cancer in humans but results of human and animal genotoxicity studies yielded conflicting results. Possibly, modes of action other than induction of DNA instability lead to malignant transformation of cells. Taken together, the existing data provide clear evidence that the MN assays with lymphocytes reflect the exposure of humans to different genotoxic metals (except cadmium) and comparisons with results obtained with other test systems in the same studies (MN assays with exfoliated cells, CA analyses, SCGE experiments) show that the findings correlate in general well with data from MN tests with lymphocytes. http://dx.doi.org/10.1016/j.toxlet.2016.06.1086 CEC5-3 Exposure to petroleum, petroleum derivatives PAHs and traffic fumes – Results of a systematic review of human studies using the lymphocyte CBMN assay Radim Sram Institute of Experimental Medicine AS CR, Prague, Czech Republic http://dx.doi.org/10.1016/j.toxlet.2016.06.1087 CEC5-4 Biomonitoring of genotoxic effects for human exposure to nanomaterials: The challenge ahead Laetitia Gonzalez, Micheline Kirsch Volders ∗ Laboratory of Cell Genetics, Vrije Universiteit Brussel, Brussels, Belgium Exposures to nanomaterials (NMs) are likely to increase over the next years, as their production is steadily rising. Therefore, there is an urgent need for the implementation of human biomonitoring studies of genotoxic effects after NM exposures in order to monitor and assure safety for workers and the general population. In this review, most commonly used biomarkers of early genetic effects were analyzed for their adequacy after NM exposures. An in depth analysis of the ex vivo/in vitro lymphocyte MN assay was performed. The known factors determining the NMs tissue/cellular targets and the modes of action of NMs were summarized. The main pending questions are whether (1) lymphocytes are a NM target or an adequate surrogate tissue, (2) whether the buccal MN assay might be more suitable for NM exposures via inhalation or ingestion, as buccal cells might be exposed more directly. While the current state-of-the-art does not allow for drawing firm conclusions, major research gaps are identified and some cautious recommendations can be formulated. Therefore, in vitro and in vivo studies should be conducted comparing methodologies side-byside in the same subjects and for different types of NMs. The ex vivo/in vitro MN assay in its automated version, allowing objective analysis of large cohorts and detection of direct and indirect genotoxic effects, remains a valuable candidate for human biomonitoring to NM exposure. Considering the potential cancer risk from
Abstracts / Toxicology Letters 258S (2016) S2–S10
exposure to NMs there is an urgent need to define and implement scientifically sound biomonitoring methods and programme for exposure to NMs. http://dx.doi.org/10.1016/j.toxlet.2016.06.1088 CEC5-5 All other chemicals – Results of systematic reviews of human exposure studies using the lymphocyte CBMN assay Stefano Bonassi Clinical and Molecular Epidemiology, IRCCS San Raffaele Pisana, Rome, Italy http://dx.doi.org/10.1016/j.toxlet.2016.06.1089 CEC 6: Green toxicology – A complementary ‘qua non’ activity for the sustainable development of chemicals and drugs in the 21st century
The campaign against polluting chemicals in textile production was initiated by Greenpeace in 2011. Now a number of major international brands and retailers, according to Greenpeace some 10 per cent of the global retail fashion industry, are committed to eliminate toxic chemicals from supply chains and to achieve zero discharge by 2020, with 11 priority chemical groups being eliminated in products and discharge released from the supply chain as well as publicly disclosing wastewater discharge data. The Zero Discharge of Hazardous Chemicals Group developed and published new processes and program documents to implement sustainable chemistry and best practices in the textile and footwear industry to protect consumers, workers and the environment. Their joint roadmap includes specific commitments and timelines to realise the shared goal. The group of brands committed to deliver work products in three focus areas, specifically chemical hazard assessment to prioritize chemicals of concern and to publish a list of chemicals for immediate further action for phase out or research. The research list contains chemicals where a safer alternative may not exist and ZDHC will phase these chemicals out once an acceptable alternative has been identified. http://dx.doi.org/10.1016/j.toxlet.2016.06.1164
CEC6-1 Twenty first century toxicology and safer chemical design
CEC6-3 Green toxicology and chemistry: Hand in glove
Thomas Hartung ∗
Bennard Van Ravenzwaay ∗ , Hennicke Kamp, Robert Landsiedel, Tzutzuy Ramirez
Johns Hopkins Bloomberg School of Public Health, United States A mechanistic, molecular research has evolved over the last decades, in parallel to the biotechnology and informatics revolution and their commercialization over the last decades. This has made such technologies broadly available, standardized and useful. This includes novel approaches toward a more organo-typic cell culture, which opens new avenues to replicate human physiology in the test tube. High-content methods such as omics technologies allow to deduce pathways of toxicity. Large curated datasets (big data) from the curation of existing data and high-throughput testing increasingly allow mining and prediction of effects of untested substances. These developments are often referred to as Twenty-first Century Toxicology. They are typically applied at the late, regulatory testing stages of product development. However, under the concept of Green Toxicology, they can help the benign design and early decision taking as to the development of certain substances to products avoiding failures in traditional regulatory tests and the market. The lecture summarizes the lessons learned from the development, validation and acceptance of alternative methods for the creation of such new approaches for Green Toxicology. http://dx.doi.org/10.1016/j.toxlet.2016.06.1163 CEC6-2 How the Greenpeace Detox campaign drives the fashion industry towards sustainable supply chains Anne Bonhoff ∗ UL Environment The fashion industry has long been regarded as one of the most ecologically harmful industries. Over 2000 different chemicals are used by the fashion and textile industry as well as large amounts of water and subsequent discharge into waterways.
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BASF SE, Ludwigshafen, Germany Reducing risks for humans and environment is the core of green chemistry and toxicity testing is a prerequisite for this. A further ethical based sustainability pillar is reduction of animal testing. At first glance these two may appear to be unrelated or even a contradiction. Animal testing enables the assessment of toxic effects and helps to develop less toxic compounds. However, animal testing comes late during development of new chemicals. The reason for this is the amount of test substance needed for animal testing. Even a limited safety testing program requires up to 0.5 kg of compound. For newly designed compounds, with complex structures, such amounts are difficult to synthesize. Moreover, in order to efficiently develop new compounds that fulfill specific requirements and are of lesser toxicity, many different structures need to be evaluated. “on–target” testing requires only one assay, for “off-target” specifications (reduced toxicity) many tests are needed. With alternative, in vitro, methods, test substance demand is greatly reduced. With only a few grams of compound many tests can be performed. Therefore, these green toxicological methods are enablers for green chemistry. Moreover, in vitro testing results can be used to develop predictive in silico tools. With such computational methods, chemists can identify alerts early and learn to avoid the synthesis of toxic compounds. Any new in vitro method for (eco)toxicity testing we will get one step closer towards an integrated process of gaining early toxicological information and adapting substance synthesis leading to the efficient development of green chemicals. http://dx.doi.org/10.1016/j.toxlet.2016.06.1165
Abstracts / Toxicology Letters 258S (2016) S2–S10
CEC 5: In vivo chemical genotoxin exposure and DNA damage in humans measured using the lymphocyte cytokinesis-block micronucleus (CBMN) assay CEC5-1 Pesticides and herbicides – Results of a systematic review of human exposure studies using the lymphocyte CBMN assay Claudia Bolognesi 1,∗ , Nina Holland 2 1
Environmental Carcinogenesis Unit, IRCCS AUO San Martino IST – National Cancer Research Institute, Genova, Italy 2 Nina Holland, School of Public Health, University of California, Berkeley, CA, USA Pesticides are widely used around the world, and hundreds of millions of people are exposed annually in occupational and environmental settings. Growing number of epidemiological and experimental studies indicate the occupational and environmental pesticide exposure as a contributing risk factor for cancer, neurodegenerative and neurodevelopmental disorders, respiratory diseases and diabetes. The pesticides exert their toxic effects through different modes of action related or not to their mechanism of action against “pest”. Experimental data revealed that many agrochemical active substances possess genotoxic properties. Assessment of genotoxicity of pesticides and biomonitoring their effects in exposed populations are critical for a better regulation and protection. A systematic review of the literature was carried out focusing on the application of the cytokinesis-block micronucleus assay in human lymphocytes (L-CBMN), a validated method for assessment of DNA damage induced by both clastogenic and aneuploidogenic mechanisms. A total of 55 full-text articles, related to 49 studies were retrieved including populations exposed to pesticides in different settings, such as chemical plant workers, pesticide sprayers, floriculturists, agricultural workers and nonoccupationally exposed groups. Majority of studies (36 out of 49) reported positive findings with L-CBMN assay. Subjects working in greenhouses or during intensive spraying season and having acute exposure, showed consistent increases in MN frequency. A decreased level of pesticide-induced genotoxicity was associated with the proper use of personal protection. Overall, this analysis confirmed that L-CBMN is an excellent tool for pesticide biomonitoring, and can validate the effects of educational and intervention programs on reducing exposure and genetic damage. http://dx.doi.org/10.1016/j.toxlet.2016.06.1085 CEC5-2 Heavy metals: Results of a systematic review of human exposure studies using the lymphocytes micronucleus assay Siegfried Knasmueller ∗ , Miroslav Miˇsík, Michael Kundi, Georg Wultsch, Armen Nersesyan Institute of Cancer Research, Department of Internal Medicine I, Medical University of Vienna, Vienna, Austria Millions of humans are exposed occupationally and environmentally to metals such as arsenic, cadmium, chromium, lead, mercury and vanadium. We evaluated the literature to find out if these metals act in humans as genotoxic carcinogens and if their effects can be detected in micronucleus assays with lymphocytes and in other genotoxicity assays. Numerous studies showed that arsenic, cadmium and chromium (VI) cause cancer and damage of
the genetic material via direct and indirect mechanisms including inhibition of DNA repair processes. Induction of DNA damage by these metals in exposed humans can be detected in MN assays with lymphocytes, i.e. almost all available studies yielded positive results. For vanadium only one human MN study has been published in which a positive effect was found; evidence for its carcinogenic properties is at present confined to data from animal experiments. For cadmium, there is an evidence that it causes cancer in humans but results of human and animal genotoxicity studies yielded conflicting results. Possibly, modes of action other than induction of DNA instability lead to malignant transformation of cells. Taken together, the existing data provide clear evidence that the MN assays with lymphocytes reflect the exposure of humans to different genotoxic metals (except cadmium) and comparisons with results obtained with other test systems in the same studies (MN assays with exfoliated cells, CA analyses, SCGE experiments) show that the findings correlate in general well with data from MN tests with lymphocytes. http://dx.doi.org/10.1016/j.toxlet.2016.06.1086 CEC5-3 Exposure to petroleum, petroleum derivatives PAHs and traffic fumes – Results of a systematic review of human studies using the lymphocyte CBMN assay Radim Sram Institute of Experimental Medicine AS CR, Prague, Czech Republic http://dx.doi.org/10.1016/j.toxlet.2016.06.1087 CEC5-4 Biomonitoring of genotoxic effects for human exposure to nanomaterials: The challenge ahead Laetitia Gonzalez, Micheline Kirsch Volders ∗ Laboratory of Cell Genetics, Vrije Universiteit Brussel, Brussels, Belgium Exposures to nanomaterials (NMs) are likely to increase over the next years, as their production is steadily rising. Therefore, there is an urgent need for the implementation of human biomonitoring studies of genotoxic effects after NM exposures in order to monitor and assure safety for workers and the general population. In this review, most commonly used biomarkers of early genetic effects were analyzed for their adequacy after NM exposures. An in depth analysis of the ex vivo/in vitro lymphocyte MN assay was performed. The known factors determining the NMs tissue/cellular targets and the modes of action of NMs were summarized. The main pending questions are whether (1) lymphocytes are a NM target or an adequate surrogate tissue, (2) whether the buccal MN assay might be more suitable for NM exposures via inhalation or ingestion, as buccal cells might be exposed more directly. While the current state-of-the-art does not allow for drawing firm conclusions, major research gaps are identified and some cautious recommendations can be formulated. Therefore, in vitro and in vivo studies should be conducted comparing methodologies side-byside in the same subjects and for different types of NMs. The ex vivo/in vitro MN assay in its automated version, allowing objective analysis of large cohorts and detection of direct and indirect genotoxic effects, remains a valuable candidate for human biomonitoring to NM exposure. Considering the potential cancer risk from
Abstracts / Toxicology Letters 258S (2016) S2–S10
exposure to NMs there is an urgent need to define and implement scientifically sound biomonitoring methods and programme for exposure to NMs. http://dx.doi.org/10.1016/j.toxlet.2016.06.1088 CEC5-5 All other chemicals – Results of systematic reviews of human exposure studies using the lymphocyte CBMN assay Stefano Bonassi Clinical and Molecular Epidemiology, IRCCS San Raffaele Pisana, Rome, Italy http://dx.doi.org/10.1016/j.toxlet.2016.06.1089 CEC 6: Green toxicology – A complementary ‘qua non’ activity for the sustainable development of chemicals and drugs in the 21st century
The campaign against polluting chemicals in textile production was initiated by Greenpeace in 2011. Now a number of major international brands and retailers, according to Greenpeace some 10 per cent of the global retail fashion industry, are committed to eliminate toxic chemicals from supply chains and to achieve zero discharge by 2020, with 11 priority chemical groups being eliminated in products and discharge released from the supply chain as well as publicly disclosing wastewater discharge data. The Zero Discharge of Hazardous Chemicals Group developed and published new processes and program documents to implement sustainable chemistry and best practices in the textile and footwear industry to protect consumers, workers and the environment. Their joint roadmap includes specific commitments and timelines to realise the shared goal. The group of brands committed to deliver work products in three focus areas, specifically chemical hazard assessment to prioritize chemicals of concern and to publish a list of chemicals for immediate further action for phase out or research. The research list contains chemicals where a safer alternative may not exist and ZDHC will phase these chemicals out once an acceptable alternative has been identified. http://dx.doi.org/10.1016/j.toxlet.2016.06.1164
CEC6-1 Twenty first century toxicology and safer chemical design
CEC6-3 Green toxicology and chemistry: Hand in glove
Thomas Hartung ∗
Bennard Van Ravenzwaay ∗ , Hennicke Kamp, Robert Landsiedel, Tzutzuy Ramirez
Johns Hopkins Bloomberg School of Public Health, United States A mechanistic, molecular research has evolved over the last decades, in parallel to the biotechnology and informatics revolution and their commercialization over the last decades. This has made such technologies broadly available, standardized and useful. This includes novel approaches toward a more organo-typic cell culture, which opens new avenues to replicate human physiology in the test tube. High-content methods such as omics technologies allow to deduce pathways of toxicity. Large curated datasets (big data) from the curation of existing data and high-throughput testing increasingly allow mining and prediction of effects of untested substances. These developments are often referred to as Twenty-first Century Toxicology. They are typically applied at the late, regulatory testing stages of product development. However, under the concept of Green Toxicology, they can help the benign design and early decision taking as to the development of certain substances to products avoiding failures in traditional regulatory tests and the market. The lecture summarizes the lessons learned from the development, validation and acceptance of alternative methods for the creation of such new approaches for Green Toxicology. http://dx.doi.org/10.1016/j.toxlet.2016.06.1163 CEC6-2 How the Greenpeace Detox campaign drives the fashion industry towards sustainable supply chains Anne Bonhoff ∗ UL Environment The fashion industry has long been regarded as one of the most ecologically harmful industries. Over 2000 different chemicals are used by the fashion and textile industry as well as large amounts of water and subsequent discharge into waterways.
S9
BASF SE, Ludwigshafen, Germany Reducing risks for humans and environment is the core of green chemistry and toxicity testing is a prerequisite for this. A further ethical based sustainability pillar is reduction of animal testing. At first glance these two may appear to be unrelated or even a contradiction. Animal testing enables the assessment of toxic effects and helps to develop less toxic compounds. However, animal testing comes late during development of new chemicals. The reason for this is the amount of test substance needed for animal testing. Even a limited safety testing program requires up to 0.5 kg of compound. For newly designed compounds, with complex structures, such amounts are difficult to synthesize. Moreover, in order to efficiently develop new compounds that fulfill specific requirements and are of lesser toxicity, many different structures need to be evaluated. “on–target” testing requires only one assay, for “off-target” specifications (reduced toxicity) many tests are needed. With alternative, in vitro, methods, test substance demand is greatly reduced. With only a few grams of compound many tests can be performed. Therefore, these green toxicological methods are enablers for green chemistry. Moreover, in vitro testing results can be used to develop predictive in silico tools. With such computational methods, chemists can identify alerts early and learn to avoid the synthesis of toxic compounds. Any new in vitro method for (eco)toxicity testing we will get one step closer towards an integrated process of gaining early toxicological information and adapting substance synthesis leading to the efficient development of green chemicals. http://dx.doi.org/10.1016/j.toxlet.2016.06.1165