Genotoxicity - A Predictable Risk to Our Actual World

SOLONESKI, S.; LARRAMENDY, M. L.

Genotoxicity - A Predictable Risk to Our Actual World

INTECH Publisher

Lugar: Rijeka; Año: 2018; p. 7 - 9

In the actual world, living species today are inevitably exposed to numerous chemical, physical and biological agents. These entities are called xenobiotics, a term derived from the Greek words ξένος (xenos) = foreigner, stranger and βίος (bios, vios) = life, plus the Greek suffix for adjectives -τικός, -ή, -ό (tic). They are typically human-made and, in most cases, are necessary in order to preserve and improve the quality of both human and the environmental health. It is estimated that humans are exposed to between one and three million different xenobiotics throughout our life cycle. These agents frequently have unexpected consequences to living organisms, however. Our understanding of how these agents can cause genetic alterations to DNA and their role in the different biological systems continues to be an area of intense interest in sectors including health, disease, pharmaceutical, environment, industry, agriculture, food, among others. The large number of untested environmental agents makes it vital that priorities are established for evaluating DNA damage inducers. Although the genotoxicity of many xenobiotics is well known even today, interest in understanding the mechanisms of action in many xenobiotics is being continuously stimulated by their continual re-evaluation. The purpose of genotoxicity is to determine whether the substance, product or environmental agent can cause genetic alterations in somatic and/or germ line cells, and then to establish the potential risk of these xenobiotics for humans and environmental organisms. Whereas DNA damage in somatic cells has been associated with degenerative conditions such as aging and cancer, it is related in germinal cells to an increased risk of infertility, spontaneous abortion or genetic and chromosomal defects in offspring that result in genetic diseases. In general terms, most of these xenobiotics are metabolised in the body to produce less toxicity. After being metabolised, however, most can be chemically reactive, leading to toxicity, potentially more toxic, and, in some cases, are carcinogenic. Carcinogenicity from various environmental causes is a major public concern because cancer is the leading cause of death in many places worldwide. Without knowledge of the genotoxic properties of the many xenobiotics, the evaluation of responses in living organisms, including humans, is difficult, and consequently the regulation of environmental genotoxicants is a complex and hard process. Accurate identification of the different classes of environmental genotoxicants would permit regulatory international scientific agencies to use this information in a variety of legislative decisions to establish priorities of public and scientific concern. Although a vast literature is available on genotoxicology, this book contains important investigations into the diverse chemical hazards encountered in both anthropogenic and natural environments, and provides valuable information about the genotoxicity of several xenobiotics that can negatively affect the health of humans and ecosystems. Organised into six chapters, this volume begins with an overview of the current advantages and disadvantages of the use of cytotoxicity and its viability in in vitro bioassays for toxicity screening. Readers are introduced to this subject to help them select the most suitable cytotoxicity and viability tests for study. The second chapter provides genotoxic information on assessment by in vitro comet assay, and by cell-free DNA quantification damage methodologies and their correlation with the enhanced inflammatory state observed in end-stage renal disease patients. The third chapter describes a study employing the retinal cells of the zebrafish Danio rerio as an in vivo model to characterise the toxic effect exerted by the synthetic pyrethroid insecticide cypermethrin, using histology, immunofluorescence, comet assay, enzyme activity and gene expression studies. The fourth chapter is an update regarding the use of the quantitative structure-activity relationships (QSAR) model, which applies multivariate statistical methods to correlate structural or molecular descriptors of known carcinogen compounds in the assessment of the carcinogenic risk of environmental chemicals. The fifth chapter is an interesting discussion about the role of extremely low frequency electromagnetic fields (EMF) on human genotoxicity, focusing on the interaction of very-low and extremely-low EMF frequencies on living systems. Finally, this book includes a chapter discussing the effects of the environmental exposure of children and pregnant women to agrochemicals, stressing their genotoxic potential in these particular human populations. The editors of Genotoxicology ? a predictable risk of our actual world are enormously grateful to all the contributing authors for sharing their knowledge and insights in this book project. They have made an extensive effort to gather the information included in every chapter. This book is designed to provide an overview of the different genotoxicants and their effects on living organisms, including humans. The contributions made by the specialists in this field of research are gratefully acknowledged. We hope that the information presented in this book will meet the expectations and needs of all those interested in the different aspects of the genotoxicity field. The publication of this book is of great importance to those scientists, pharmacologists, physicians, and veterinarians as well as engineers, teachers, graduate students, and administrators of environmental programmes, who make use of these investigations to understand both the basic and applied genotoxic aspects of known and new xenobiotics, and to guide them in their future investigations.