Progresos y retos de la Toxicología Genética / Progress and challenges of Genetic Toxicology

Resumen: Esta revisión resume los principales avances de la citogenética y proporciona una perspectiva sobre el futuro de la toxicología genética, desde el pasado, presente y futuro, tanto desde el punto de vista genético como epigenético. Los principios de la citogenética clásica han evolucionado con el tiempo, interactuando con enfoques de toxicología para dar lugar a la toxicología genética o mutagénesis ambiental. Actualmente, están surgiendo estudios toxicogenómicos basados en estudios de toxicología genética estándar, y uno de los principales objetivos de la toxicogenómica es detectar relaciones entre cambios en la expresión génica global y criterios de valoración toxicológicos, con el fin de comprender el papel de las interacciones gen-ambiente en la enfermedad. Para alcanzar este objetivo, la toxicogenómica combina la toxicología, la genética, tecnologías de perfiles moleculares de alto rendimiento como la transcriptómica, proteómica, metabolómica y la bioinformática. En este campo, muchas limitaciones restringen el papel de los nuevos hallazgos y enfoques. Por ejemplo, el costo de las nuevas tecnologías; sin embargo, su aplicación contribuirá a una mejor comprensión de las interacciones gen-ambiente y de esta manera, establecer políticas orientadas a prevenir riesgos para la salud, para que se viva una vida más saludable en un ambiente más favorable. (AU)

This review summarizes the main advances of cytogenetic and provides a perspective on the future of genetic toxicology, reviewing from past, present, and future, both genetics and epigenetic point of view. The principles of classical cytogenetics have evolved over time, interacting with toxicology approaches to give rise to genetic toxicology or environmental mutagenesis. Currently, toxicogenomic studies are emerging based on standard genetic toxicology studies, and one major goal of toxicogenomic is to detect relationships between changes in global gene expression and toxicological endpoints, in order to understand the role of gene-environment interactions in disease. To reach this goal, toxicogenomics combines toxicology, genetic, with genomics or other high throughput molecular profiling technologies such as transcriptomics, proteomics, metabolomics, and bioinformatics. In this field, many limitations are restricting the role of the novel findings and approaches. For example, the cost of new technologies; however, its application will contribute to a better understanding of gene-environment interactions and in this way, establish policies aimed at preventing health risks, so that a healthier life is lived in a friendlier environment. (AU)

Implementing organ-on-chip in a next-generation risk assessment of chemicals: a review.

Organ-on-chip (OoC) technology is full of engineering and biological challenges, but it has the potential to revolutionize the Next-Generation Risk Assessment of novel ingredients for consumer products and chemicals. A successful incorporation of OoC technology into the Next-Generation Risk Assessment toolbox depends on the robustness of the microfluidic devices and the organ tissue models used. Recent advances in standardized device manufacturing, organ tissue cultivation and growth protocols offer the ability to bridge the gaps towards the implementation of organ-on-chip technology. Next-Generation Risk Assessment is an exposure-led and hypothesis-driven tiered approach to risk assessment using detailed human exposure information and the application of appropriate new (non-animal) toxicological testing approaches. Organ-on-chip presents a promising in vitro approach by combining human cell culturing with dynamic microfluidics to improve physiological emulation. Here, we critically review commercial organ-on-chip devices, as well as recent tissue culture model studies of the skin, intestinal barrier and liver as the main metabolic organ to be used on-chip for Next-Generation Risk Assessment. Finally, microfluidically linked tissue combinations such as skin-liver and intestine-liver in organ-on-chip devices are reviewed as they form a relevant aspect for advancing toxicokinetic and toxicodynamic studies. We point to recent achievements and challenges to overcome, to advance non-animal, human-relevant safety studies.

Perspectives of future lung toxicology studies using human pluripotent stem cells.

The absence of in vitro platforms for human pulmonary toxicology studies is becoming an increasingly serious concern. The respiratory system has a dynamic mechanical structure that extends from the airways to the alveolar region. In addition, the epithelial, endothelial, stromal, and immune cells are highly organized in each region and interact with each other to function synergistically. These cells of varied lineage, particularly epithelial cells, have been difficult to use for long-term culture in vitro, thus limiting the development of useful experimental tools. This limitation has set a large distance between the bench and the bedside for analyzing the pathogenic mechanisms, the efficacy of candidate therapeutic agents, and the toxicity of compounds. Several researchers have proposed solutions to these problems by reporting on methods for generating human lung epithelial cells derived from pluripotent stem cells (PSCs). Moreover, the use of organoid culture, organ-on-a-chip, and material-based techniques have enabled the maintenance of functional PSC-derived lung epithelial cells as well as primary cells. The aforementioned technological advances have facilitated the in vitro recapitulation of genetic lung diseases and the detection of ameliorating or worsening effects of genetic and chemical interventions, thus indicating the future possibility of more sophisticated preclinical compound assessments in vitro. In this review, we will update the recent advances in lung cell culture methods, principally focusing on human PSC-derived lung epithelial organoid culture systems with the hope of their future application in toxicology studies.

Pioneer women in the development of toxicology in Brazil.

Women have always played an important role in the development of toxicology all over the world. Specifically in Brazil, toxicology has had greater female representation than other countries, but women's participation at high hierarchical levels is low. Although more than 62% of the members of the Brazilian Society of Toxicology are women, only 7 out of the 22 presidents have been women throughout its 48 years of existence. This article aims to celebrate women in the field of toxicology in Brazil, based on interviews with five of these scientists who have changed the field of toxicology in Brazil as we know it today, each in their specific sub-areas. These women are: Dr. Ester de Camargo Fonseca Moraes, Dr. Silvia Berlanga de Moraes Barros, Dr. Alice Aparecida da Matta Chasin, Dr. Gisela de Aragão Umbuzeiro, and Dr. Tania Marcourakis. They are not only pioneers but they are also examples of admirable persistence in fighting the adversities presented to them. They broke the glass ceiling and opened doors for future generations of women in science. We hope that this article helps inspire women in their careers in toxicology.

Pioneer women in the development of toxicology in Brazil

Women have always played an important role in the development of toxicology all over the world. Specifically in Brazil, toxicology has had greater female representation than other countries, but women's participation at high hierarchical levels is low. Although more than 62% of the members of the Brazilian Society of Toxicology are women, only 7 out of the 22 presidents have been women throughout its 48 years of existence. This article aims to celebrate women in the field of toxicology in Brazil, based on interviews with five of these scientists who have changed the field of toxicology in Brazil as we know it today, each in their specific sub-areas. These women are: Dr. Ester de Camargo Fonseca Moraes, Dr. Silvia Berlanga de Moraes Barros, Dr. Alice Aparecida da Matta Chasin, Dr. Gisela de Aragão Umbuzeiro, and Dr. Tania Marcourakis. They are not only pioneers but they are also examples of admirable persistence in fighting the adversities presented to them. They broke the glass ceiling and opened doors for future generations of women in science. We hope that this article helps inspire women in their careers in toxicology.

Rethinking Nano-TiO2 Safety: Overview of Toxic Effects in Humans and Aquatic Animals.

Titanium dioxide nanoparticles (nano-TiO2 ) are widely used in consumer products, raising environmental and health concerns. An overview of the toxic effects of nano-TiO2 on human and environmental health is provided. A meta-analysis is conducted to analyze the toxicity of nano-TiO2 to the liver, circulatory system, and DNA in humans. To assess the environmental impacts of nano-TiO2 , aquatic environments that receive high nano-TiO2 inputs are focused on, and the toxicity of nano-TiO2 to aquatic organisms is discussed with regard to the present and predicted environmental concentrations. Genotoxicity, damage to membranes, inflammation and oxidative stress emerge as the main mechanisms of nano-TiO2 toxicity. Furthermore, nano-TiO2 can bind with free radicals and signal molecules, and interfere with the biochemical reactions on plasmalemma. At the higher organizational level, nano-TiO2 toxicity is manifested as the negative effects on fitness-related organismal traits including feeding, reproduction and immunity in aquatic organisms. Bibliometric analysis reveals two major research hot spots including the molecular mechanisms of toxicity of nano-TiO2 and the combined effects of nano-TiO2 and other environmental factors such as light and pH. The possible measures to reduce the harmful effects of nano-TiO2 on humans and non-target organisms has emerged as an underexplored topic requiring further investigation.

Non-clinical combination toxicology studies: strategy, examples and future perspective.

Over the last decade, combination of drugs in all stages of pharmaceutical development has accelerated availability of promising new therapies for difficult to treat diseases. Safety assessment of combined drugs to be tested in humans can occur at a critical path prior to proceeding in clinical testing. A recent survey by The International Consortium for Innovation and Quality in Pharmaceutical Development (IQ DruSafe) summarized member companies' approaches to combination safety strategies. In addition, feedback from Health Authorities (HAs) support a case-by-case scientific approach in assessing combination products' safety in accordance with the International Council on Harmonization (ICH) guidelines. Here, we present Pfizer's drug combination safety approach for various therapeutic areas (TA) including inflammation and immunology, metabolic, and anti-cancer products. There is no one-size-fits-all approach; rather, our main considerations include: strength of the existing clinical safety data for the individual compounds, common target organs, the potential for a synergistic effect, potential drug-drug interaction, routes of administration of each product and disease indications. No formal toxicity studies are considered necessary for anti-cancer drugs, while safety endpoints may be collected in preclinical pharmacology studies especially when the combined drugs present a novel mechanism. Combination safety studies when conducted for non-cancer indications can range from 2 to 13-weeks in duration, conducted usually in rodents, with dosages of individual molecules within clinical pharmacologic ranges. A case-by-case strategy guided by scientific rationale and in close collaboration with HAs remains the best approach to decide on the design and conduct of combination safety studies.

Research trends in chemico-biological interactions: The golden jubilee (1969-2019).

Since its inception in 1969, Chemico-Biological Interactions (CBI) has persistently published high quality research articles. As part of the journal's golden anniversary (50 years), we performed an electronic search on Scopus to get all publications details. Based on citescore, ranking & percentile, CBI holds 21st position in the top 113 relevant journals (in 2018). CBI also completed publications of 8005 manuscripts in March 2020. The highest documents were articles (6972/87.09%) followed by conference papers (588/7.34%) and reviews (252/3.14%). The maximum number of publications (385) was recorded in 2019, followed by 366 (in 2010) and 336 in 2016. Furthermore, details of the top 50 countries, top 50 authors and top 20 institutes with total publications, h-index, total citations and without selfcitations (WSC) are provided. USA (2371), China (786) and United Kingdom (658) are the top three countries, O'Brien, P.J (48), Maser, E. (45) and Lockridge, O. (35) are the top three authors and Karolinska Institutet (144), Stockholm University (102) & Ministry of Education China (94) are the top three institutes involved in research publications. More than eighty-four thousand (84,000) key words were amassed from scopus and after critical analysis we proposed a common sequence and connectivity. The top 200 articles, 200 reviews and 200 conference papers were analyzed by Vosviewer for various parameters. While, the top three (3) research articles and reviews are briefly described. The bibliometric analyses confirm a noteworthy growth of CBI in research publications and scientometric performance.

Role of Artificial Intelligence and Machine Learning in Nanosafety.

Robotics and automation provide potentially paradigm shifting improvements in the way materials are synthesized and characterized, generating large, complex data sets that are ideal for modeling and analysis by modern machine learning (ML) methods. Nanomaterials have not yet fully captured the benefits of automation, so lag behind in the application of ML methods of data analysis. Here, some key developments in, and roadblocks to the application of ML methods are reviewed to model and predict potentially adverse biological and environmental effects of nanomaterials. This work focuses on the diverse ways a range of ML algorithms are applied to understand and predict nanomaterials properties, provides examples of the application of traditional ML and deep learning methods to nanosafety, and provides context and future perspectives on developments that are likely to occur, or need to occur in the near future that allow artificial intelligence to make a deeper contribution to nanosafety.

Understanding Nanomaterial Biotransformation: An Unmet Challenge to Achieving Predictive Nanotoxicology.

More than a decade has passed since the first concepts of predictive nanotoxicology were formulated. During this time, many advancements have been achieved in multiple disciplines, including the success stories of the fiber paradigm and the oxidative stress paradigm. However, important knowledge gaps are slowing down the development of predictive nanotoxicology and require a mutidisciplinary effort to be overcome. Among these gaps, understanding, reproducing, and modeling of nanomaterial biotransformation in biological environments is a central challenge, both in vitro and in silico. This dynamic and complex process is still a challenge for today's bioanalytics. This work explores and discusses selected approaches of the multidisciplinary efforts taken in the last decade and the challenges that remain unmet, in particular concerning nanomaterial biotransformation. It highlights some future advancements that, together, can help to understand such complex processes and accelerate the development of predictive nanotoxicology.

Safety Considerations of Cancer Nanomedicine-A Key Step toward Translation.

The rate of translational effort of nanomedicine requires strategic planning of nanosafety research in order to enable clinical trials and safe use of nanomedicine in patients. Herein, the experiences that have emerged based on the safety data of classic liposomal formulations in the space of oncology are discussed, along with a description of the new challenges that need to be addressed according to the rapid expansion of nanomedicine platform beyond liposomes. It is valuable to consider the combined use of predictive toxicological assessment supported by deliberate investigation on aspects such as absorption, distribution, metabolism, and excretion (ADME) and toxicokinetic profiles, the risk that may be introduced during nanomanufacture, unique nanomaterials properties, and nonobvious nanosafety endpoints, for example. These efforts will allow the generation of investigational new drug-enabling safety data that can be incorporated into a rational infrastructure for regulatory decision-making. Since the safety assessment relates to nanomaterials, the investigation should cover the important physicochemical properties of the material that may lead to hazards when the nanomedicine product is utilized in humans.

Molecular Mechanisms, Characterization Methods, and Utilities of Nanoparticle Biotransformation in Nanosafety Assessments.

It is a big challenge to reveal the intrinsic cause of a nanotoxic effect due to diverse branches of signaling pathways induced by engineered nanomaterials (ENMs). Biotransformation of toxic ENMs involving biochemical reactions between nanoparticles (NPs) and biological systems has recently attracted substantial attention as it is regarded as the upstream signal in nanotoxicology pathways, the molecular initiating event (MIE). Considering that different exposure routes of ENMs may lead to different interfaces for the arising of biotransformation, this work summarizes the nano-bio interfaces and dose calculation in inhalation, dermal, ingestion, and injection exposures to humans. Then, five types of biotransformation are shown, including aggregation and agglomeration, corona formation, decomposition, recrystallization, and redox reactions. Besides, the characterization methods for investigation of biotransformation as well as the safe design of ENMs to improve the sustainable development of nanotechnology are also discussed. Finally, future perspectives on the implications of biotransformation in clinical translation of nanomedicine and commercialization of nanoproducts are provided.

21st Century Tools for Nanotoxicology: Transcriptomic Biomarker Panel and Precision-Cut Lung Slice Organ Mimic System for the Assessment of Nanomaterial-Induced Lung Fibrosis.

There is an urgent need for reliable toxicity assays to support the human health risk assessment of an ever increasing number of engineered nanomaterials (ENMs). Animal testing is not a suitable option for ENMs. Sensitive in vitro models and mechanism-based targeted in vitro assays that enable accurate prediction of in vivo responses are not yet available. In this proof-of-principle study, publicly available mouse lung transcriptomics data from studies investigating xenobiotic-induced lung diseases are used and a 17-gene biomarker panel (PFS17) applicable to the assessment of lung fibrosis is developed. The PFS17 is validated using a limited number of in vivo mouse lung transcriptomics datasets from studies investigating ENM-induced responses. In addition, an ex vivo precision-cut lung slice (PCLS) model is optimized for screening of potentially inflammogenic and pro-fibrotic ENMs. Using bleomycin and a multiwalled carbon nanotube, the practical application of the PCLS method as a sensitive alternative to whole animal tests to screen ENMs that may potentially induce inhalation toxicity is shown. Conditional to further optimization and validation, it is established that a combination of PFS17 and the ex vivo PCLS method will serve as a robust and sensitive approach to assess lung inflammation and fibrosis induced by ENMs.

The promise of toxicogenomics for genetic toxicology: past, present and future.

Toxicogenomics, the application of genomics to toxicology, was described as 'a new era' for toxicology. Standard toxicity tests typically involve a number of short-term bioassays that are costly, time consuming, require large numbers of animals and generally focus on a single end point. Toxicogenomics was heralded as a way to improve the efficiency of toxicity testing by assessing gene regulation across the genome, allowing rapid classification of compounds based on characteristic expression profiles. Gene expression microarrays could measure and characterise genome-wide gene expression changes in a single study and while transcriptomic profiles that can discriminate between genotoxic and non-genotoxic carcinogens have been identified, challenges with the approach limited its application. As such, toxicogenomics did not transform the field of genetic toxicology in the way it was predicted. More recently, next generation sequencing (NGS) technologies have revolutionised genomics owing to the fact that hundreds of billions of base pairs can be sequenced simultaneously cheaper and quicker than traditional Sanger methods. In relation to genetic toxicology, and thousands of cancer genomes have been sequenced with single-base substitution mutational signatures identified, and mutation signatures have been identified following treatment of cells with known or suspected environmental carcinogens. RNAseq has been applied to detect transcriptional changes following treatment with genotoxins; modified RNAseq protocols have been developed to identify adducts in the genome and Duplex sequencing is an example of a technique that has recently been developed to accurately detect mutation. Machine learning, including MutationSeq and SomaticSeq, has also been applied to somatic mutation detection and improvements in automation and/or the application of machine learning algorithms may allow high-throughput mutation sequencing in the future. This review will discuss the initial promise of transcriptomics for genetic toxicology, and how the development of NGS technologies and new machine learning algorithms may finally realise that promise.

[Advances in the application of clinical toxicology in the treatment of acute poisoning].

Acute poisoning is a component of emergency medicine and a key public health problem in clinical toxicology. In recent years, the research and development of industrial chemicals and drugs have developed rapidly, and the incidence of acute drug poisoning has been increasing. It is very important to strengthen the application research of clinical toxicology in acute poisoning, to identify rare and new toxic drugs, and to create conditions for rapid detection of toxic substances. Therefore, this article reviews the types of acute poisoning, the epidemiological characteristics, the detection technology and significance of clinical toxicology, the role of clinical toxicology in the treatment of acute poisoning and its application.

Bibliometric profile of global scientific research on digoxin toxicity (1849-2015).

Digoxin is a cardiac glycoside derived from the common foxglove digitalis purpurea and has been available for several centuries as a medicinal agent. Despite extensive patient experience over many years, there remains some controversy regarding the possibility that digoxin might have a deleterious effect on survival. This study was constructed to assess trends in digoxin toxicity research using well-established qualitative and quantitative bibliometric indicators. The current study is based on publications that have been indexed in Scopus. Articles referring to the subject of digoxin toxicity between 1849 and 2015 were assessed according to the document type, publication language, countries/territories, institutions, journal, impact factors, total number of citations, h-index, average number of citations per publication, and international collaborations. There were 2900 publications that included 2542 (87.7%) original research articles, while 5.3% were reviews and 4.6% letters. The country of origin was the USA in 849 publications, Germany in 241, the UK in 150, and France in 143. The USA and the UK had the highest number of international collaborations. The average number of citations per publications related to digoxin toxicity was 8.1, and the h-index was 59. The USA and Canada had the highest h-indices by country at 46 and 22, respectively. This study presents the first bibliometric analysis on digoxin toxicity publications. The USA was the most important contributors to digoxin toxicity literature with the greatest international collaboration, largest number of articles and highest h-index, followed by Germany and the UK. There has been a trend towards reduced publication numbers related to digoxin toxicity at global level, although it is still an important issue and we present the current research themes related to digoxin toxicity that were identified.

Vision of a near future: Bridging the human health-environment divide. Toward an integrated strategy to understand mechanisms across species for chemical safety assessment.

There is a growing recognition that application of mechanistic approaches to understand cross-species shared molecular targets and pathway conservation in the context of hazard characterization, provide significant opportunities in risk assessment (RA) for both human health and environmental safety. Specifically, it has been recognized that a more comprehensive and reliable understanding of similarities and differences in biological pathways across a variety of species will better enable cross-species extrapolation of potential adverse toxicological effects. Ultimately, this would also advance the generation and use of mechanistic data for both human health and environmental RA. A workshop brought together representatives from industry, academia and government to discuss how to improve the use of existing data, and to generate new NAMs data to derive better mechanistic understanding between humans and environmentally-relevant species, ultimately resulting in holistic chemical safety decisions. Thanks to a thorough dialogue among all participants, key challenges, current gaps and research needs were identified, and potential solutions proposed. This discussion highlighted the common objective to progress toward more predictive, mechanistically based, data-driven and animal-free chemical safety assessments. Overall, the participants recognized that there is no single approach which would provide all the answers for bridging the gap between mechanism-based human health and environmental RA, but acknowledged we now have the incentive, tools and data availability to address this concept, maximizing the potential for improvements in both human health and environmental RA.