Environmental Effects of Endocrine-Disrupting Chemicals: A Special Focus on Phthalates and Bisphenol A

Several environmental chemicals are classified as endocrine-disrupting chemicals (EDCs). Many of them have an impact on reproductive functions and sex hormones because of their estrogenic and/or antiandrogenic properties. Phthalates and bisphenol A (BPA) are two well-known EDCs. They are abundant in the environment. Phthalates are usually classified as antiandrogens, whereas BPA is considered as estrogen-like EDC and xenoestrogen. Other than their endocrine-disrupting effects, these two chemicals are also known to have genotoxic and epigenetic effects. Besides, they are hepatotoxic and have substantial effects on other organs/systems (thyroid, kidney, neuroendocrine system, immune system, etc.). In this chapter, we will mainly focus on the toxic effects of different phthalate esters and BPA by discussing their availability in the environment, mechanism and mode of actions, their biotransformation and reproductive effects, and their effects on other systems (hepatic, renal, etc.). Besides, we discuss epidemiological studies that are conducted to reveal their effects on the reproductive and endocrine systems. This chapter provides the readers a compact piece of knowledge on these abundant substances and helps them to understand the action of these substances at the molecular and cellular levels

Antioksidansi i spojevi selenija inhibiraju toksično djelovanje 3,5-dimetilaminofenola na epitelne bubrežne stanice u ljudi

Exposure to alkyl anilines may lead to bladder cancer, which is the second most frequent cancer of the urogenital tract. 3,5-dimethylaniline is highly used in industry. Studies on its primary metabolite 3,5-dimethylaminophenol (3,5-DMAP) showed that this compound causes oxidative stress, changes antioxidant enzyme activities, and leads to death of different mammalian cells. However, there is no in vitro study to show the direct effects of 3,5-DMAP on human bladder and urothelial cells. Selenocompounds are suggested to decrease oxidative stress caused by some chemicals, and selenium supplementation was shown to reduce the risk of bladder cancer. The main aim of this study was to investigate whether selenocompounds organic selenomethionine (SM, 10 μmol/L) or inorganic sodium selenite (SS, 30 nmol/L) could reduce oxidative stress, DNA damage, and apoptosis in UROtsa cells exposed to 3,5-DMAP. 3,5-DMAP caused a dose-dependent increase in intracellular generation of reactive oxygen species, and its dose of 50 μmol/L caused lipid peroxidation, protein oxidation, and changes in antioxidant enzyme activities in different cellular fractions. The comet assay also showed single-strand DNA breaks induced by the 3,5-DMAP dose of 50 μmol/L, but no changes in double-strand DNA breaks. Apoptosis was also triggered. Both selenocompounds provided partial protection against the cellular toxicity of 3,5-DMAP. Low selenium status along with exposure to alkyl anilines can be a major factor in the development of bladder cancer. More mechanistic studies are needed to specify the role of selenium in bladder cancer.Izloženost alkilnim anilinima može uzrokovati rak mokraćnoga mjehura, koji je drugi po redu po učestalosti raka mokraćnospolnog sustava. 3,5-dimetilanilin često se rabi u industrijskoj proizvodnji, a istraživanja njegova primarnog metabolita, 3,5-dimetilaminofenola (3,5-DMAP), pokazuju da on uzrokuje oksidacijski stres i promjene u aktivnosti antioksidacijskih enzima te u konačnici dovodi do smrti raznih stanica u sisavaca. Dosad, međutim, nije provedeno nijedno istraživanje njegovih izravnih učinaka na epitelne stanice mokraćnoga mjehura i bubrega u ljudi. Za spojeve selenija smatra se da smanjuju oksidacijski stres različitih kemikalija te da dopuna prehrane selenijem smanjuje rizik od raka mokraćnoga mjehura. Primarni je cilj ovoga istraživanja bio utvrditi može li organski spoj selenija selenometionin (SM, 10 μmol/L), odnosno anorganski spoj natrijev selenit (SS, 30 nmol/L], smanjiti oksidacijski stres, oštećenje DNA i apoptozu u UROtsa stanicama izloženima 3,5-dimetilaminofenolu. Jednosatna izloženost stanica 3,5-DMAP-u dovela je do povećanja razina reaktivnih kisikovih spojeva (ROS), lipidne peroksidacije, oksidacije bjelančevina te do promjena u aktivnosti antioksidacijskih enzima u staničnoj citoplazmi i jezgri, ovisno o primijenjenoj dozi. Osim toga, komet-testom su utvrđeni jednolančani, ali ne i dvolančani lomovi DNA. Također, 3,5-DMAP uzrokovao je apoptozu stanica. Oba su spoja selenija pružila djelomičnu zaštitu od njegova toksičnoga djelovanja. Nedostatak selenija pri izloženosti alkilnim anilinskim spojevima stoga može odigrati značajnu ulogu u nastanku raka mokraćnog mjehura. Potrebna su daljnja istraživanja mehanizama djelovanja selenija u njegovu sprječavanju

Oncogenes and Carcinogenesis

Oncogenes are mutated and/or overexpressed at high levels in tumor cells. Tumors of the lung, breast, pancreas, and colon may display specific oncogenetic features. These tumors have been largely associated with exposure to environmental carcinogens and a variety of biological agents, including viruses. These carcinogens can induce specific genetic and epigenetic alterations in these tissues, leading to aberrant functioning of oncogenes and tumor suppressor genes. On the microRNAs (miRNAs) there are significant modifiers of both transcription and translation of oncogenes in carcinogenesis. In the last 50 years, several oncogenes and microRNAs related to these oncogenes have been identified in different types of human cancers. It is now clear that high expression of oncogenes, DNA damage response, and regulation of the cell cycle are related to the circadian clock. This book will mainly focus on the expressions of different oncogenes in breast, colon, and lung cancers. Moreover, readers will gain qualified scientific knowledge of the alterations in miRNAs in different types of cancers and the effects of the circadian clock on the expression of oncogenes in carcinogenesis

Toxicity Of Acrylamide And Evaluation Of Its Exposure In Baby Foods

Contaminants are a vast subject area of food safety and quality and can be present in our food chain from raw materials to finished products. Acrylamide, an alpha,beta-unsaturated (conjugated) reactive molecule, can be detected as a contaminant in several foodstuffs including baby foods and infant formulas. It is anticipated that children will generally have intakes that are two to three times those of adults when expressed on a body-weight basis. Though exposure to acrylamide is inevitable, it is necessary to protect infant and children from high exposure. The present review focuses on the several adverse health effects of acrylamide including mutagenicity, genotoxicity, carcinogenicity, neurotoxicity and reproductive toxicity, and the possible outcomes of childhood exposure from baby foods and infant formulas.WoSScopu

Glutathione in Health and Disease

Reduced glutathione (GSH) is the most important thiol in living organisms. It is the key component of antioxidant system and serves as a free radical scavenger. There is a cycle of GSH in biological systems and this cycle provides higher intracellular levels of GSH. GSH depletion and apparent oxidative stress may cause toxicity and can affect the general well-being of the organism. GSH was shown to be preventive against aging, cancer, heart disease, infections and dementia. This book is mainly focused on GSH in health and disease. The readers will gain qualified scientific knowledge on the diverse functions of GSH, the importance of GSH status against oxidative stress and the interaction between GSH and nervous system-related infections from this book

Bisphenol A Exposure and Health Risks

Bisphenol A (BPA) is a synthetic compound for hardening and clearing polycarbonate plastics. BPA is mainly classified as an estrogen-like endocrine-disrupting chemical. In the last decade, attention has arisen in scientific communities that it is not safe to use this chemical in mainly polycarbonate plastics. Exposure to BPA starts in prenatal period, which is the critical period for its toxic effects on different organs. Throughout this book, the readers will obtain information on the effects of BPA on different systems. They will also get information on the prenatal and postnatal effects of BPA. We believe that readers will get qualified scientific knowledge and a general overview of the toxic effects of BPA exposure and its consequences from this book

Toxicological Evaluation Of Weight Loss Patches: Review

Obesity is defined as increased amount of energy sources stored as body fat in mammalians and human beings, to the extent that it may have adverse effects on health. It is very common around the world and a leading cause of morbidity and mortality. Excessive intake of calories, lack of exercise and genetic predisposition are the main causes, however, medical treatment and psychiatric conditions may infrequently result in obesity. There are many commercial products on the market to prevent obesity. Many products are effective when used together with diet and physical exercise, however, some are claimed to be effective without changing the lifestyle. Obesity bands are self adhesive transdermal products that are replaced every day or week, and are reported to help losing weight. These products contain herbal mixtures. The most common ingredients are combinations of Fucus vesiculosis, Guarana and Garcina cambogia. These patches may result in adverse effects when used inappropriately. Adverse effects may be serious in sensitive patients. In addition to adverse effects, they may cause delay in treatment. Since use of weight loss patches may prevent the treatment of obesity-related disorders that can be treated by diet, exercise and medical treatment, their usage may not be justified. Current review evaluates the ingredients of weight loss patches and toxicological results associated with use of these products.WoSScopu