1 5450 146 REPRODUCTIVE TOXICITY OF COMBINED EFFECTS OF ENDOCRINE DISRUPTORS ON HUMAN REPRODUCTION. CONFLUENCE OF ENVIRONMENTAL, GENETIC, AND LIFESTYLE VARIABLES IS RESPONSIBLE FOR DETERIORATION OF HUMAN FECUNDITY. ENDOCRINE DISRUPTORS OR ENDOCRINE DISRUPTING CHEMICALS (EDCS) MAY BE FOUND IN A VARIETY OF FOODS, WATER, AIR, BEVERAGES, AND TOBACCO SMOKE. IT HAS BEEN DEMONSTRATED IN EXPERIMENTAL INVESTIGATIONS THAT A WIDE RANGE OF ENDOCRINE DISRUPTING CHEMICALS HAVE NEGATIVE EFFECTS ON HUMAN REPRODUCTIVE FUNCTION. HOWEVER, EVIDENCE ON THE REPRODUCTIVE CONSEQUENCES OF HUMAN EXPOSURE TO ENDOCRINE DISRUPTING CHEMICALS IS SPARSE AND/OR CONFLICTING IN THE SCIENTIFIC LITERATURE. THE COMBINED TOXICOLOGICAL ASSESSMENT IS A PRACTICAL METHOD FOR ASSESSING THE HAZARDS OF COCKTAILS OF CHEMICALS, CO-EXISTING IN THE ENVIRONMENT. THE CURRENT REVIEW PROVIDES A COMPREHENSIVE OVERVIEW OF STUDIES EMPHASIZING THE COMBINED TOXICITY OF ENDOCRINE DISRUPTING CHEMICALS ON HUMAN REPRODUCTION. ENDOCRINE DISRUPTING CHEMICALS INTERACT WITH EACH OTHER TO DISRUPT THE DIFFERENT ENDOCRINE AXES, RESULTING IN SEVERE GONADAL DYSFUNCTIONS. TRANSGENERATIONAL EPIGENETIC EFFECTS HAVE ALSO BEEN INDUCED IN GERM CELLS, MOSTLY THROUGH DNA METHYLATION AND EPIMUTATIONS. SIMILARLY, AFTER ACUTE OR CHRONIC EXPOSURE TO ENDOCRINE DISRUPTING CHEMICALS COMBINATIONS, INCREASED OXIDATIVE STRESS (OS), ELEVATED ANTIOXIDANT ENZYMATIC ACTIVITY, DISRUPTED REPRODUCTIVE CYCLE, AND REDUCED STEROIDOGENESIS ARE OFTEN REPORTED CONSEQUENCES. THE ARTICLE ALSO DISCUSSES THE CONCENTRATION ADDITION (CA) AND INDEPENDENT ACTION (IA) PREDICTION MODELS, WHICH REVEAL THE IMPORTANCE OF VARIOUS SYNERGISTIC ACTIONS OF ENDOCRINE DISRUPTING CHEMICALS MIXTURES. MORE CRUCIALLY, THIS EVIDENCE-BASED STUDY ADDRESSES THE RESEARCH LIMITATIONS AND INFORMATION GAPS, AS WELL AS PARTICULARLY PRESENTS THE FUTURE RESEARCH VIEWS ON COMBINED ENDOCRINE DISRUPTING CHEMICALS TOXICITY ON HUMAN REPRODUCTION. 2023 2 1644 39 DOES THE ENVIRONMENT AFFECT MENOPAUSE? A REVIEW OF THE EFFECTS OF ENDOCRINE DISRUPTING CHEMICALS ON MENOPAUSE. ENDOCRINE DISRUPTING CHEMICALS ARE WIDELY DISTRIBUTED IN OUR ENVIRONMENT. HUMANS ARE EXPOSED TO THESE COMPOUNDS NOT ONLY THROUGH THEIR OCCUPATIONS, BUT ALSO THROUGH DIETARY CONSUMPTION AND EXPOSURE TO CONTAMINATED WATER, PERSONAL CARE PRODUCTS AND TEXTILES. CHEMICALS THAT ARE PERSISTENT IN THE BODY AND IN OUR ENVIRONMENT INCLUDE DIOXINS AND POLYCHLORINATED BIPHENYLS. NON-PERSISTENT CHEMICALS INCLUDING BISPHENOL A, PHTHALATES AND PARABENS ARE EQUALLY AS IMPORTANT BECAUSE THEY ARE UBIQUITOUS IN OUR ENVIRONMENT. HEAVY METALS, INCLUDING LEAD AND CADMIUM, CAN ALSO HAVE ENDOCRINE DISRUPTING PROPERTIES. ALTHOUGH DIFFICULT TO STUDY DUE TO THEIR VARIETY OF SOURCES OF EXPOSURES AND MECHANISMS OF ACTION, THESE CHEMICALS HAVE BEEN ASSOCIATED WITH EARLY MENOPAUSE, INCREASED FREQUENCY OF VASOMOTOR SYMPTOMS, ALTERED STEROID HORMONE LEVELS AND MARKERS OF DIMINISHED OVARIAN RESERVE. UNDERSTANDING THE IMPACTS OF THESE EXPOSURES IS IMPORTANT GIVEN THE POTENTIAL FOR EPIGENETIC MODIFICATION, WHICH CAN ALTER GENE FUNCTION AND RESULT IN MULTI-GENERATIONAL EFFECTS. THIS REVIEW SUMMARIZES FINDINGS IN HUMANS AND ANIMALS OR CELL-BASED MODELS FROM THE PAST DECADE OF RESEARCH. CONTINUED RESEARCH IS NEEDED TO ASSESS THE EFFECTS OF MIXTURES OF CHEMICALS, CHRONIC EXPOSURES AND NEW COMPOUNDS THAT ARE CONTINUOUSLY BEING DEVELOPED AS REPLACEMENTS FOR TOXIC CHEMICALS THAT ARE BEING PHASED OUT. 2023 3 4805 44 OBESITY AND METABOLIC COMORBIDITIES: ENVIRONMENTAL DISEASES? OBESITY AND METABOLIC COMORBIDITIES REPRESENT INCREASING HEALTH PROBLEMS. ENDOCRINE DISRUPTING COMPOUNDS (EDCS) ARE EXOGENOUS AGENTS THAT CHANGE ENDOCRINE FUNCTION AND CAUSE ADVERSE HEALTH EFFECTS. MOST EDCS ARE SYNTHETIC CHEMICALS; SOME ARE NATURAL FOOD COMPONENTS AS PHYTOESTROGENS. PEOPLE ARE EXPOSED TO COMPLEX MIXTURES OF CHEMICALS THROUGHOUT THEIR LIVES. EDCS IMPACT HORMONE-DEPENDENT METABOLIC SYSTEMS AND BRAIN FUNCTION. LABORATORY AND HUMAN STUDIES PROVIDE COMPELLING EVIDENCE THAT HUMAN CHEMICAL CONTAMINATION CAN PLAY A ROLE IN OBESITY EPIDEMIC. CHEMICAL EXPOSURES MAY INCREASE THE RISK OF OBESITY BY ALTERING THE DIFFERENTIATION OF ADIPOCYTES. EDCS CAN ALTER METHYLATION PATTERNS AND NORMAL EPIGENETIC PROGRAMMING IN CELLS. OXIDATIVE STRESS MAY BE INDUCED BY MANY OF THESE CHEMICALS, AND ACCUMULATING EVIDENCE INDICATES THAT IT PLAYS IMPORTANT ROLES IN THE ETIOLOGY OF CHRONIC DISEASES. THE INDIVIDUAL SENSITIVITY TO CHEMICALS IS VARIABLE, DEPENDING ON ENVIRONMENT AND ABILITY TO METABOLIZE HAZARDOUS CHEMICALS. A NUMBER OF GENES, ESPECIALLY THOSE REPRESENTING ANTIOXIDANT AND DETOXIFICATION PATHWAYS, HAVE POTENTIAL APPLICATION AS BIOMARKERS OF RISK ASSESSMENT. THE POTENTIAL HEALTH EFFECTS OF COMBINED EXPOSURES MAKE THE RISK ASSESSMENT PROCESS MORE COMPLEX COMPARED TO THE ASSESSMENT OF SINGLE CHEMICALS. TECHNIQUES AND METHODS NEED TO BE FURTHER DEVELOPED TO FILL DATA GAPS AND INCREASE THE KNOWLEDGE ON HARMFUL EXPOSURE COMBINATIONS. 2013 4 5493 21 REVIEW OF IN VITRO TEST SYSTEMS USING DNA DAMAGE AND REPAIR FOR SCREENING OF CHEMICAL CARCINOGENS. CHEMICAL CARCINOGENS ARE MECHANISTICALLY CLASSIFIED AS GENOTOXIC WHICH INTERACT DIRECTLY WITH DNA, AND EPIGENETIC WHICH CAUSE CHRONIC TISSUE INJURY, HORMONAL IMBALANCE, AND PROMOTIONAL EFFECTS. THIS REVIEW EVALUATES IN VITRO TESTS FOR THEIR CONTRIBUTION TO A BATTERY FOR IDENTIFYING GENOTOXIC CHEMICAL CARCINOGENS. IN ADDITION TO BACTERIAL MUTAGENIC ASSAYS, NONSPECIFIC DNA DAMAGE/REPAIR TESTS ARE RECOMMENDED FOR SCREENING CHEMICALS, IN PARTICULAR THE HEPATOCYTE PRIMARY CULTURE/DNA REPAIR TEST. 1979 5 567 29 BASIC PROPERTIES AND MOLECULAR MECHANISMS OF EXOGENOUS CHEMICAL CARCINOGENS. EXOGENOUS CHEMICAL CARCINOGENESIS IS AN EXTREMELY COMPLEX MULTIFACTORIAL PROCESS DURING WHICH GENE-ENVIRONMENT INTERACTIONS INVOLVING CHRONIC EXPOSURE TO EXOGENOUS CHEMICAL CARCINOGENS (ECCS) AND POLYMORPHISMS OF CANCER SUSCEPTIBILITY GENES ADD FURTHER COMPLEXITY. WE DESCRIBE THE PROPERTIES AND MOLECULAR MECHANISMS OF ECCS THAT CONTRIBUTE TO INDUCE AND GENERATE CANCER. A BASIC AND SPECIFIC PROPERTY OF MANY LIPOPHILIC ORGANIC ECCS INCLUDING POLYCYCLIC AROMATIC HYDROCARBONS AND POLYHALOGENATED AROMATIC HYDROCARBONS IS THEIR ABILITY TO BIOACCUMULATE IN THE ADIPOSE TISSUE FROM WHERE THEY MAY BE RELEASED IN THE BLOOD CIRCULATION AND TARGET PERIPHERAL TISSUES FOR CARCINOGENESIS. MANY ORGANIC ECCS ARE PROCARCINOGENS AND CONSEQUENTLY NEED TO BE ACTIVATED BY THE CYTOCHROME P450 (CYP) SYSTEM AND/OR OTHER ENZYMES BEFORE THEY CAN ADDUCT DNA AND PROTEINS. BECAUSE THEY CONTRIBUTE NOT ONLY TO THE COCARCINOGENIC AND PROMOTING EFFECTS OF MANY AROMATIC POLLUTANTS BUT ALSO TO THEIR MUTAGENIC EFFECTS, THE ARYL HYDROCARBON RECEPTOR-ACTIVATING AND THE INDUCIBLE CYP SYSTEMS ARE CENTRAL TO EXOGENOUS CHEMICAL CARCINOGENESIS. ANOTHER BASIC PROPERTY OF ECCS IS THEIR ABILITY TO INDUCE STABLE AND BULKY DNA ADDUCTS THAT CANNOT BE SIMPLY REPAIRED BY THE DIFFERENT REPAIR SYSTEMS. IN ADDITION, FOLLOWING ECC EXPOSURE, MUTAGENESIS MAY ALSO BE CAUSED INDIRECTLY BY FREE-RADICAL PRODUCTION AND BY EPIGENETIC ALTERATIONS. AS A RESULT OF COMPLEX MOLECULAR INTERPLAYS, DIRECT AND/OR INDIRECT MUTAGENESIS MAY ESPECIALLY ACCOUNT FOR THE CARCINOGENIC EFFECTS OF MANY EXOGENOUS METALS AND METALLOIDS. BECAUSE OF THESE MOLECULAR PROPERTIES AND ACTION MECHANISMS, WE CONCLUDE THAT ECCS COULD BE MAJOR CONTRIBUTORS TO HUMAN CANCER, WITH OBVIOUSLY GREAT PUBLIC HEALTH CONSEQUENCES. 2010 6 1767 39 EARLY-LIFE EXPOSURE TO ENDOCRINE DISRUPTING CHEMICALS AND LATER-LIFE HEALTH OUTCOMES: AN EPIGENETIC BRIDGE? A GROWING BODY OF EVIDENCE DEMONSTRATES THAT ADVERSE EVENTS EARLY IN DEVELOPMENT, AND PARTICULARLY DURING INTRAUTERINE LIFE, MAY PROGRAM RISKS FOR DISEASES IN ADULT LIFE. INCREASING EVIDENCE HAS BEEN ACCUMULATED INDICATING THE IMPORTANT ROLE OF EPIGENETIC REGULATION INCLUDING DNA METHYLATION, HISTONE MODIFICATIONS AND MIRNAS IN DEVELOPMENTAL PROGRAMMING. AMONG THE ENVIRONMENTAL FACTORS WHICH PLAY AN IMPORTANT ROLE IN PROGRAMMING OF CHRONIC PATHOLOGIES, THE ENDOCRINE-DISRUPTING CHEMICALS (EDCS) THAT HAVE ESTROGENIC, ANTI-ESTROGENIC, AND ANTI-ANDROGENIC ACTIVITY ARE OF SPECIFIC CONCERN BECAUSE THE DEVELOPING ORGANISM IS EXTREMELY SENSITIVE TO PERTURBATION BY SUBSTANCES WITH HORMONE-LIKE ACTIVITY. AMONG EDCS, THERE ARE MANY SUBSTANCES THAT ARE CONSTANTLY PRESENT IN THE MODERN HUMAN ENVIRONMENT OR ARE IN WIDESPREAD USE, INCLUDING DIOXIN AND DIOXIN-LIKE COMPOUNDS, PHTHALATES, AGRICULTURAL PESTICIDES, POLYCHLORINATED BIPHENYLS, INDUSTRIAL SOLVENTS, PHARMACEUTICALS, AND HEAVY METALS. APART FROM THEIR COMMON ENDOCRINE ACTIVE PROPERTIES, SEVERAL EDCS HAVE BEEN SHOWN TO DISRUPT DEVELOPMENTAL EPIGENOMIC PROGRAMMING. THE PURPOSE OF THIS REVIEW IS TO PROVIDE A SUMMARY OF RECENT RESEARCH FINDINGS WHICH INDICATE THAT EXPOSURE TO EDCS DURING IN-UTERO AND/OR NEONATAL DEVELOPMENT CAN CAUSE LONG-TERM HEALTH OUTCOMES VIA MECHANISMS OF EPIGENETIC MEMORY. 2014 7 1857 29 ELIMINATION OF PERSISTENT TOXICANTS FROM THE HUMAN BODY. THERE IS COMPELLING EVIDENCE THAT VARIOUS CHEMICAL AGENTS ARE IMPORTANT DETERMINANTS OF MYRIAD HEALTH AFFLICTIONS--SEVERAL XENOBIOTICS HAVE THE POTENTIAL TO DISRUPT REPRODUCTIVE, DEVELOPMENTAL, AND NEUROLOGICAL PROCESSES AND SOME AGENTS IN COMMON USE HAVE CARCINOGENIC, EPIGENETIC, ENDOCRINE-DISRUPTING, AND IMMUNE-ALTERING ACTION. SOME TOXICANTS APPEAR TO HAVE BIOLOGICAL EFFECT AT MINISCULE LEVELS AND CERTAIN CHEMICAL COMPOUNDS ARE PERSISTENT AND BIOACCUMULATIVE WITHIN THE HUMAN BODY. DESPITE ESCALATING PUBLIC HEALTH MEASURES TO PRECLUDE FURTHER EXPOSURES, MANY PEOPLE THROUGHOUT THE WORLD HAVE ALREADY ACCRUED A SIGNIFICANT BODY BURDEN OF TOXICANTS, PLACING THEM AT POTENTIAL HEALTH RISK. AS A RESULT, INCREASING DISCUSSION IS UNDERWAY ABOUT POSSIBLE INTERVENTIONS TO FACILITATE ELIMINATION OF PERSISTENT TOXICANTS FROM THE HUMAN ORGANISM IN ORDER TO OBVIATE HEALTH AFFLICTION AND TO POTENTIALLY AMELIORATE CHRONIC DEGENERATIVE ILLNESS. AN OVERVIEW OF THE CLINICAL ASPECTS OF DETOXIFICATION IS PRESENTED WITH DISCUSSION OF ESTABLISHED AND EMERGING INTERVENTIONS FOR THE ELIMINATION OF PERSISTENT XENOBIOTICS. POTENTIAL THERAPIES TO CIRCUMVENT ENTEROHEPATIC RECIRCULATION AND A CASE REPORT HIGHLIGHTING A CLINICAL OUTCOME ASSOCIATED WITH DETOXIFICATION ARE ALSO PRESENTED FOR CONSIDERATION. 2011 8 1352 35 DEVELOPMENT AND APPLICATION OF THE ADVERSE OUTCOME PATHWAY FRAMEWORK FOR UNDERSTANDING AND PREDICTING CHRONIC TOXICITY: I. CHALLENGES AND RESEARCH NEEDS IN ECOTOXICOLOGY. TO ELUCIDATE THE EFFECTS OF CHEMICALS ON POPULATIONS OF DIFFERENT SPECIES IN THE ENVIRONMENT, EFFICIENT TESTING AND MODELING APPROACHES ARE NEEDED THAT CONSIDER MULTIPLE STRESSORS AND ALLOW RELIABLE EXTRAPOLATION OF RESPONSES ACROSS SPECIES. AN ADVERSE OUTCOME PATHWAY (AOP) IS A CONCEPT THAT PROVIDES A FRAMEWORK FOR ORGANIZING KNOWLEDGE ABOUT THE PROGRESSION OF TOXICITY EVENTS ACROSS SCALES OF BIOLOGICAL ORGANIZATION THAT LEAD TO ADVERSE OUTCOMES RELEVANT FOR RISK ASSESSMENT. IN THIS PAPER, WE FOCUS ON EXPLORING HOW THE AOP CONCEPT CAN BE USED TO GUIDE RESEARCH AIMED AT IMPROVING BOTH OUR UNDERSTANDING OF CHRONIC TOXICITY, INCLUDING DELAYED TOXICITY AS WELL AS EPIGENETIC AND TRANSGENERATIONAL EFFECTS OF CHEMICALS, AND OUR ABILITY TO PREDICT ADVERSE OUTCOMES. A BETTER UNDERSTANDING OF THE INFLUENCE OF SUBTLE TOXICITY ON INDIVIDUAL AND POPULATION FITNESS WOULD SUPPORT A BROADER INTEGRATION OF SUBLETHAL ENDPOINTS INTO RISK ASSESSMENT FRAMEWORKS. DETAILED MECHANISTIC KNOWLEDGE WOULD FACILITATE THE DEVELOPMENT OF ALTERNATIVE TESTING METHODS AS WELL AS HELP PRIORITIZE HIGHER TIER TOXICITY TESTING. WE ARGUE THAT TARGETED DEVELOPMENT OF AOPS SUPPORTS BOTH OF THESE ASPECTS BY PROMOTING THE ELUCIDATION OF MOLECULAR MECHANISMS AND THEIR CONTRIBUTION TO RELEVANT TOXICITY OUTCOMES ACROSS BIOLOGICAL SCALES. WE FURTHER DISCUSS INFORMATION REQUIREMENTS AND CHALLENGES IN APPLICATION OF AOPS FOR CHEMICAL- AND SITE-SPECIFIC RISK ASSESSMENT AND FOR EXTRAPOLATION ACROSS SPECIES. WE PROVIDE RECOMMENDATIONS FOR POTENTIAL EXTENSION OF THE AOP FRAMEWORK TO INCORPORATE INFORMATION ON EXPOSURE, TOXICOKINETICS AND SITUATION-SPECIFIC ECOLOGICAL CONTEXTS, AND DISCUSS COMMON INTERFACES THAT CAN BE EMPLOYED TO COUPLE AOPS WITH COMPUTATIONAL MODELING APPROACHES AND WITH EVOLUTIONARY LIFE HISTORY THEORY. THE EXTENDED AOP FRAMEWORK CAN SERVE AS A VENUE FOR INTEGRATION OF KNOWLEDGE DERIVED FROM VARIOUS SOURCES, INCLUDING EMPIRICAL DATA AS WELL AS MOLECULAR, QUANTITATIVE AND EVOLUTIONARY-BASED MODELS DESCRIBING SPECIES RESPONSES TO TOXICANTS. THIS WILL ALLOW A MORE EFFICIENT APPLICATION OF AOP KNOWLEDGE FOR QUANTITATIVE CHEMICAL- AND SITE-SPECIFIC RISK ASSESSMENT AS WELL AS FOR EXTRAPOLATION ACROSS SPECIES IN THE FUTURE. 2015 9 1919 37 ENVIRONMENTAL ENDOCRINE DISRUPTORS: NEW DIABETOGENS? THE PREVALENCE OF TYPE-2 DIABETES HAS DRAMATICALLY INCREASED WORLDWIDE DURING THE LAST FEW DECADES. WHILE LIFESTYLE FACTORS (SEDENTARINESS, NOXIOUS FOOD), TOGETHER WITH GENETIC SUSCEPTIBILITY, ARE WELL-KNOWN ACTORS, THERE IS ACCUMULATING EVIDENCE SUGGESTING THAT ENDOCRINE DISRUPTING CHEMICALS (EDCS) MAY ALSO PLAY A PATHOPHYSIOLOGICAL ROLE IN THE OCCURRENCE OF METABOLIC DISEASES. BOTH EXPERIMENTAL AND EPIDEMIOLOGICAL EVIDENCE SUPPORT A ROLE FOR EARLY AND CHRONIC EXPOSURE TO LOW DOSES OF CHEMICAL POLLUTANTS WITH ENDOCRINE AND METABOLIC DISRUPTING EFFECTS. MOST ARE PRESENT IN THE FOOD CHAIN AND ACCUMULATE IN THE FAT MASS AFTER ABSORPTION. IN RODENTS, BISPHENOL A STIMULATES SYNTHESIS AND SECRETION OF PANCREATIC BETA CELLS AND DISTURBS INSULIN SIGNALING IN LIVER, MUSCLE AND ADIPOSE TISSUE THROUGH EPIGENETIC CHANGES LEADING TO INSULIN RESISTANCE AND BETA CELL IMPAIRMENT. IN HUMANS, EPIDEMIOLOGICAL REPORTS SHOW STATISTICAL LINK BETWEEN EXPOSURE TO PESTICIDES, POLYCHLORINATED BISPHENYLS, BISPHENOL A, PHTHALATES, DIOXINS OR AROMATIC POLYCYCLIC HYDROCARBIDES OR HEAVY METALS AND DT2 AFTER ACUTE ACCIDENTAL RELEASES OR EARLY IN LIFE AND/OR CHRONIC, LOW DOSES EXPOSURE. MORE PROSPECTIVE, LONGITUDINAL STUDIES ARE NEEDED TO DETERMINE THE IMPORTANCE OF SUCH ENVIRONMENTAL RISK FACTORS. 2017 10 1106 72 COMBINED TOXICITY OF ENDOCRINE-DISRUPTING CHEMICALS: A REVIEW. THE COMBINED TOXICOLOGICAL ASSESSMENT PROVIDES A REALISTIC APPROACH FOR HAZARD EVALUATION OF CHEMICAL COCKTAILS THAT CO-EXISTED IN THE ENVIRONMENT. THIS REVIEW PROVIDES A HOLISTIC INSIGHT INTO THE STUDIES HIGHLIGHTING THE MIXTURE TOXICITY OF THE ENDOCRINE-DISRUPTING CHEMICALS (EDCS), ESPECIALLY FOCUSING ON THE SCREENING OF BIOCHEMICAL PATHWAYS AND OTHER TOXICOGENETIC ENDPOINTS. REVIEWED LITERATURE SHOWED THAT NUMEROUS MULTIPLEXED TOXICOGENOMIC TECHNIQUES WERE APPLIED TO DETERMINE REPRODUCTIVE EFFECTS IN VERTEBRATES, BUT LIMITED STUDIES WERE FOUND IN NON-MAMMALIAN SPECIES AFTER MIXTURE CHEMICAL EXPOSURE. FURTHER, WE FOUND THAT THE EXPERIMENTAL DESIGN AND CONCENTRATION SELECTION ARE THE TWO IMPORTANT PARAMETERS IN MIXTURE TOXICITY STUDIES THAT SHOULD BE TIME- AND COST-EFFECTIVE, HIGHLY PRECISE, AND ENVIRONMENTALLY RELEVANT. A SUMMARY OF EDC MIXTURES AFFECTING THE THYROID AXIS, ESTROGEN AXIS, ANDROGEN AXIS, GROWTH STRESS, AND IMMUNE SYSTEM VIA IN VIVO BIOASSAYS WAS ALSO PRESENTED. IT IS INTERESTING TO MENTION THAT MAJORITY OF ESTROGENIC EFFECTS OF THE MIXTURES WERE SEX-DEPENDENT, PARTICULARLY OBSERVED IN MALE FISH AS COMPARED TO FEMALE FISH. FURTHER, THE ANDROGEN AXIS WAS PERTURBED WITH SERIOUS MALFORMATIONS IN MALE RAT TESTIS (EPIDIDYMAL OR GUBERNACULAR LESIONS, AND DECIDUOUS SPERMATIDS). ALSO, TRANSGENERATIONAL EPIGENETIC EFFECTS WERE PROMOTED IN THE F(3) AND F(4) GENERATIONS IN THE FORM OF DNA METHYLATION EPIMUTATIONS IN SPERM, INCREASING POLYCYSTIC OVARIES AND REDUCING THE OFFSPRING. SIMILARLY, INCREASED OXIDATIVE STRESS, HIGH ANTIOXIDANT ENZYMATIC ACTIVITIES, DISTURBED ESTROUS CYCLE, AND DECREASED STEROIDOGENESIS WERE THE COMMONLY FOUND EFFECTS AFTER ACUTE OR CHRONIC EXPOSURE TO EDC MIXTURES. IMPORTANTLY, THE CONCENTRATION ADDITION (CA) AND INDEPENDENT ACTION (IA) MODELS BECAME MORE PREVALENT AND SUITABLE PREDICTIVE MODELS TO UNVEIL THE PROMINENCE OF SYNERGISTIC ESTROGENIC AND ANTI-ANDROGENIC EFFECTS OF CHEMICAL MIXTURES. MORE IMPORTANTLY, THIS REVIEW ENCOMPASSES THE RESEARCH CHALLENGES AND GAPS IN THE EXISTING KNOWLEDGE AND SPECIFIC FUTURE RESEARCH PERSPECTIVES ON COMBINED TOXICITY. 2021 11 835 34 CHEMICAL CARCINOGEN MECHANISMS OF ACTION AND IMPLICATIONS FOR TESTING METHODOLOGY. CHEMICAL CARCINOGENS ARE OF TWO DISTINCT TYPES, DNA-REACTIVE AND EPIGENETIC. TESTING METHODOLOGY CAN BE DIRECTED TOWARD DETECTING EFFECTS OF BOTH TYPES OF CARCINOGEN. CARCINOGENS OF THE DNA-REACTIVE TYPE ARE DEFINED BY THE FORMATION OF COVALENTLY BOUND DNA ADDUCTS. THESE CHEMICALS HAVE STRUCTURES THAT YIELD ELECTROPHILIC REACTANTS EITHER DIRECTLY OR AFTER BIOACTIVATION. THESE AGENTS CAUSE GENOMIC ALTERATION IN THE STRUCTURE OR FUNCTION OF DNA IN THE TARGET CELL. IN ADDITION, THESE COMPOUNDS CAN EXERT OTHER CELLULAR AND TISSUE EPIGENETIC EFFECTS, SUCH AS CELL PROLIFERATION AND GROWTH PROMOTION. CARCINOGENS OF THE EPIGENETIC (PARAGENETIC) TYPE, IN CONTRAST, DO NOT REACT WITH DNA, BUT RATHER DISPLAY CELLULAR EFFECTS SUCH AS NEOPLASM GROWTH PROMOTION, CYTOTOXICITY, INHIBITION OF TISSUE GROWTH REGULATION, PEROXISOME PROLIFERATION, ENDOCRINE MODIFICATION, IMMUNOSUPPRESSION AND/OR SUSTAINED TISSUE ISCHEMIA THAT CAN BE THE BASIS FOR INCREASES IN NEOPLASIA. THEIR CHEMICAL STRUCTURE IS SUCH THAT THEY DO NOT GIVE RISE TO A REACTIVE ELECTROPHILE. THE TESTING METHODOLOGIES TO IDENTIFY EITHER TYPE FOLLOW A DECISION POINT APPROACH DESIGNED TO IDENTIFY POTENTIAL CARCINOGENICITY AND YIELD MECHANISTIC INFORMATION ON THE PRODUCTION OF EFFECTS THAT UNDERLIE CARCINOGENICITY. IT HAS 5 STAGES FOCUSING ON THE CHEMICAL STRUCTURE, DNA-REACTIVITY, EPIGENETIC EFFECTS, LIMITED BIOASSAYS AND FINALLY THE APPLICATION OF THE ACCELERATED BIOASSAY (ABA). ABA REQUIRES 40 WEEKS AND APPLIES THE USE OF SENSITIVE MARKERS FOR INDUCTION OF NEOPLASIA IN COMPARISON TO POSITIVE CONTROL COMPOUNDS FOR IMPORTANT ORGANS IN HUMAN CARCINOGENESIS. IT ENABLES DATA ACQUISITION OF THE ENTIRE CARCINOGENIC PROCESS DIRECTED TOWARD DEVELOPING MECHANISTIC INFORMATION. THE ABA HAS THE POTENTIAL TO REPLACE THE CHRONIC BIOASSAY IN RODENTS IN SOME CIRCUMSTANCES AND CAN SERVE AS AN ALTERNATIVE TO A CHRONIC BIOASSAY IN A SECOND SPECIES. 1996 12 108 40 A REVIEW OF THE PROTECTIVE EFFECT OF MELATONIN IN PESTICIDE-INDUCED TOXICITY. PESTICIDES ARE AMONG THE MOST IMPORTANT CHEMICALS USED IN AGRICULTURE SECTOR. HOWEVER, THEIR EXTENSIVE USE HAS POLLUTED THE ENVIRONMENT AND INCREASED HUMAN VULNERABILITY TO VARIOUS CHRONIC DISEASES. PESTICIDE EXPOSURE CAUSES GENETIC AND EPIGENETIC MODIFICATIONS, ENDOCRINE DISRUPTION, MITOCHONDRIAL DYSFUNCTION AND OXIDATIVE STRESS. AREAS COVERED: THIS REVIEW IS BASED ON THE LITERATURE STUDIES CURRENTLY REPORTED ON PESTICIDE-INDUCED TOXICITY AND THE PROTECTIVE ROLE OF MELATONIN. SCIENTIFIC DATABASES SUCH AS PUBMED, SCOPUS AND WEB OF SCIENCE WERE SEARCHED USING KEYWORDS 'PESTICIDE' AND 'MELATONIN' UP TO JANUARY 2016. FULL LENGTH ARTICLES RELATED TO ANIMAL AND HUMAN EXPOSURE WERE RETRIEVED. A TOTAL NUMBER OF 181 RECORDS WERE OBTAINED, AND AFTER EXCLUDING THE DUPLICATES, 97 PAPERS WERE FURTHER SCREENED ON THE BASIS OF RELEVANCE TO THE TOPIC. EXPERT OPINION: MELATONIN AS A BROAD-SPECTRUM ANTIOXIDANT IS ABLE TO PENETRATE CELLULAR COMPARTMENTS SPECIFICALLY THE MITOCHONDRIA. IT IS A POTENT FREE RADICAL SCAVENGER WITH LOW TOXICITY AND DESIRABLE SOLUBILITY IN ORGANIC AND AQUEOUS PHASES. WE ARE OF THE OPINION THAT MELATONIN IS A PROMISING AGENT IN MINIMIZING ORGAN INJURIES INDUCED BY PESTICIDES. 2017 13 4541 43 MULTISYSTEMIC ALTERATIONS IN HUMANS INDUCED BY BISPHENOL A AND PHTHALATES: EXPERIMENTAL, EPIDEMIOLOGICAL AND CLINICAL STUDIES REVEAL THE NEED TO CHANGE HEALTH POLICIES. A VAST AMOUNT OF EVIDENCE INDICATES THAT BISPHENOL A (BPA) AND PHTHALATES ARE WIDELY DISTRIBUTED IN THE ENVIRONMENT SINCE THESE COMPOUNDS ARE MASS-PRODUCED FOR THE MANUFACTURE OF PLASTICS AND PLASTICIZERS. THESE COMPOUNDS BELONG TO A LARGE GROUP OF SUBSTANCES TERMED ENDOCRINE-DISRUPTING CHEMICALS (EDC). IT IS WELL KNOWN THAT HUMANS AND LIVING ORGANISMS ARE UNAVOIDABLY AND UNINTENTIONALLY EXPOSED TO BPA AND PHTHALATES FROM FOOD PACKAGING MATERIALS AND MANY OTHER EVERYDAY PRODUCTS. BPA AND PHTHALATES EXERT THEIR EFFECT BY INTERFERING WITH HORMONE SYNTHESIS, BIOAVAILABILITY, AND ACTION, THEREBY ALTERING CELLULAR PROLIFERATION AND DIFFERENTIATION, TISSUE DEVELOPMENT, AND THE REGULATION OF SEVERAL PHYSIOLOGICAL PROCESSES. IN FACT, THESE EDC CAN ALTER FETAL PROGRAMMING AT AN EPIGENETIC LEVEL, WHICH CAN BE TRANSGENERATIONAL TRANSMITTED AND MAY BE INVOLVED IN THE DEVELOPMENT OF VARIOUS CHRONIC PATHOLOGIES LATER IN THE ADULTHOOD, INCLUDING METABOLIC, REPRODUCTIVE AND DEGENERATIVE DISEASES, AND CERTAIN TYPES OF CANCER. IN THIS REVIEW, WE DESCRIBE THE MOST RECENT PROPOSED MECHANISMS OF ACTION OF THESE EDC AND OFFER A COMPELLING SELECTION OF EXPERIMENTAL, EPIDEMIOLOGICAL AND CLINICAL STUDIES, WHICH SHOW EVIDENCE OF HOW EXPOSURE TO THESE POLLUTANTS AFFECTS OUR HEALTH DURING DEVELOPMENT, AND THEIR ASSOCIATION WITH A WIDE RANGE OF REPRODUCTIVE, METABOLIC AND NEUROLOGICAL DISEASES, AS WELL AS HORMONE-RELATED CANCERS. WE STRESS THE IMPORTANCE OF CONCERN IN THE GENERAL POPULATION AND THE URGENT NEED FOR THE MEDICAL HEALTH CARE SYSTEM TO CLOSELY MONITOR EDC LEVELS IN THE POPULATION DUE TO UNAVOIDABLE AND INVOLUNTARY EXPOSURE TO THESE POLLUTANTS AND THEIR IMPACT ON HUMAN HEALTH. 2021 14 3566 42 IMPACT OF HEAVY METALS ON THE FEMALE REPRODUCTIVE SYSTEM. INTRODUCTION: IT HAS BEEN RECOGNIZED THAT ENVIRONMENTAL POLLUTION CAN AFFECT THE QUALITY OF HEALTH OF THE HUMAN POPULATION. HEAVY METALS ARE AMONG THE GROUP OF HIGHLY EMITTED CONTAMINANTS AND THEIR ADVERSE EFFECT OF LIVING ORGANISMS HAS BEEN WIDELY STUDIED IN RECENT DECADES. LIFESTYLE AND QUALITY OF THE AMBIENT ENVIRONMENT ARE AMONG THESE FACTORS WHICH CAN MAINLY CONTRIBUTE TO THE HEAVY METALS EXPOSURE IN HUMANS. OBJECTIVE: A REVIEW OF LITERATURE LINKING HEAVY METALS AND THE FEMALE REPRODUCTIVE SYSTEM AND DESCRIPTION OF THE POSSIBLE ASSOCIATIONS WITH EMISSION AND EXPOSURE OF HEAVY METALS AND IMPAIRMENTS OF FEMALE REPRODUCTIVE SYSTEM ACCORDING TO CURRENT KNOWLEDGE. RESULTS: THE POTENTIAL HEALTH DISORDERS CAUSED BY CHRONIC OR ACUTE HEAVY METALS TOXICITY INCLUDE IMMUNODEFICIENCY, OSTEOPOROSIS, NEURODEGENERATION AND ORGAN FAILURES. POTENTIAL LINKAGES OF HEAVY METALS CONCENTRATION FOUND IN DIFFERENT HUMAN ORGANS AND BLOOD WITH OESTROGEN-DEPENDENT DISEASES SUCH AS BREAST CANCER, ENDOMETRIAL CANCER, ENDOMETRIOSIS AND SPONTANEOUS ABORTIONS, AS WELL AS PRE-TERM DELIVERIES, STILLBIRTHS AND HYPOTROPHY, HAVE ALSO BEEN REPORTED. CONCLUSIONS: ENVIRONMENTAL DETERIORATION CAN LEAD TO THE ELEVATED RISK OF HUMAN EXPOSURE TO HEAVY METALS, AND CONSEQUENTLY, HEALTH IMPLICATIONS INCLUDING DISTURBANCES IN REPRODUCTION. IT IS THEREFORE IMPORTANT TO CONTINUE THE INVESTIGATIONS ON METAL-INDUCED MECHANISMS OF FERTILITY IMPAIRMENT ON THE GENETIC, EPIGENETIC AND BIOCHEMICAL LEVEL. 2015 15 4881 33 OVERVIEW OF THE CARDIOVASCULAR EFFECTS OF ENVIRONMENTAL METALS: NEW PRECLINICAL AND CLINICAL INSIGHTS. ENVIRONMENTAL CAUSES OF CARDIOVASCULAR DISEASES (CVDS) ARE GLOBAL HEALTH ISSUES. IN PARTICULAR, AN ASSOCIATION BETWEEN METAL EXPOSURE AND CVDS HAS BECOME EVIDENT BUT CAUSAL EVIDENCE STILL LACKS. THEREFORE, THIS SYMPOSIUM AT THE SOCIETY OF TOXICOLOGY 2022 ANNUAL MEETING ADDRESSED EPIDEMIOLOGICAL, CLINICAL, PRE-CLINICAL ANIMAL MODEL-DERIVED AND MECHANISM-BASED EVIDENCE BY FIVE PRESENTATIONS: 1) AN EPIDEMIOLOGIC STUDY ON POTENTIAL CVD RISKS OF INDIVIDUALS EXPOSED OCCUPATIONALLY AND ENVIRONMENTALLY TO HEAVY METALS; 2) BOTH PRESENTATIONS OF THE SECOND AND THIRD WERE CLINICAL STUDIES FOCUSING ON THE POTENTIAL LINK BETWEEN HEAVY METALS AND PULMONARY ARTERIAL HYPERTENSION (PAH), BY PRESENTING ALTERED BLOOD METAL CONCENTRATIONS OF BOTH NON-ESSENTIAL AND ESSENTIAL METALS IN THE PATIENTS WITH PAH AND POTENTIAL THERAPEUTIC APPROACHES; 3) ARSENIC-INDUCED ATHEROSCLEROSIS VIA INFLAMMATORY CELLS IN MOUSE MODEL; 4) PATHOGENIC EFFECTS ON THE HEART BY ADULT CHRONIC EXPOSURE TO VERY LOW-DOSE CADMIUM VIA EPIGENETIC MECHANISMS AND WHOLE LIFE EXPOSURE TO LOW DOSE CADMIUM VIA EXACERBATING HIGH-FAT-DIET-LIPOTOXICITY. THIS SYMPOSIUM HAS BROUGHT EPIDEMIOLOGISTS, THERAPEUTIC INDUSTRY, PHYSICIANS, AND TRANSLATIONAL SCIENTISTS TOGETHER TO DISCUSS THE HEALTH RISKS OF OCCUPATIONAL AND ENVIRONMENTAL EXPOSURE TO HEAVY METALS THROUGH DIRECT CARDIOTOXICITY AND INDIRECT DISRUPTION OF HOMEOSTATIC MECHANISMS REGULATING ESSENTIAL METALS, AS WELL AS LIPID LEVELS. THE DATA SUMMARIZED BY THE PRESENTERS INFERS A POTENTIAL CAUSAL LINK BETWEEN MULTIPLE METALS AND CVDS AND DEFINES DIFFERENCES AND COMMONALITIES. THEREFORE, SUMMARY OF THESE PRESENTATIONS MAY ACCELERATE THE DEVELOPMENT OF EFFICIENT PREVENTIVE AND THERAPEUTIC STRATEGIES BY FACILITATING COLLABORATIONS AMONG MULTIDISCIPLINARY INVESTIGATORS. 2022 16 633 33 BIOLOGICAL EFFECTS AND EPIDEMIOLOGICAL CONSEQUENCES OF ARSENIC EXPOSURE, AND REAGENTS THAT CAN AMELIORATE ARSENIC DAMAGE IN VIVO. THROUGH CONTAMINATED DIET, WATER, AND OTHER FORMS OF ENVIRONMENTAL EXPOSURE, ARSENIC AFFECTS HUMAN HEALTH. THERE ARE MANY U.S. AND WORLDWIDE "HOT SPOTS" WHERE THE ARSENIC LEVEL IN PUBLIC WATER EXCEEDS THE MAXIMUM EXPOSURE LIMIT. THE BIOLOGICAL EFFECTS OF CHRONIC ARSENIC EXPOSURE INCLUDE GENERATION OF REACTIVE OXYGEN SPECIES (ROS), LEADING TO OXIDATIVE STRESS AND DNA DAMAGE, EPIGENETIC DNA MODIFICATION, INDUCTION OF GENOMIC INSTABILITY, AND INFLAMMATION AND IMMUNOMODULATION, ALL OF WHICH CAN INITIATE CARCINOGENESIS. HIGH ARSENIC EXPOSURE IS EPIDEMIOLOGICALLY ASSOCIATED WITH SKIN, LUNG, BLADDER, LIVER, KIDNEY AND PANCREATIC CANCER, AND CARDIOVASCULAR, NEURONAL, AND OTHER DISEASES. THIS REVIEW BRIEFLY SUMMARIZES THE BIOLOGICAL EFFECTS OF ARSENIC EXPOSURE AND EPIDEMIOLOGICAL CANCER STUDIES WORLDWIDE, AND PROVIDES AN OVERVIEW FOR EMERGING RODENT-BASED STUDIES OF REAGENTS THAT CAN AMELIORATE THE EFFECTS OF ARSENIC EXPOSURE IN VIVO. THESE REAGENTS MAY BE TRANSLATED TO HUMAN POPULATIONS FOR DISEASE PREVENTION. WE PROPOSE THE IMPORTANCE OF DEVELOPING A BIOMARKER-BASED PRECISION PREVENTION APPROACH FOR THE HEALTH ISSUES ASSOCIATED WITH ARSENIC EXPOSURE THAT AFFECTS MILLIONS OF PEOPLE WORLDWIDE. 2017 17 4652 33 NEUROPROTECTION WITH NATURAL ANTIOXIDANTS AND NUTRACEUTICALS IN THE CONTEXT OF BRAIN CELL DEGENERATION: THE EPIGENETIC CONNECTION. BIOACTIVE ANTIOXIDANT AGENTS PRESENT IN SELECTED PLANTS ARE KNOWN TO PROVIDE THE FIRST LINE OF BIOLOGICAL DEFENSE AGAINST OXIDATIVE STRESS. IN PARTICULAR, SOLUBLE VITAMIN C, E, CAROTENOIDS AND PHENOLIC COMPOUNDS HAVE DEMONSTRATED CRUCIAL BIOLOGICAL EFFECTS IN CELLS AGAINST OXIDATIVE DAMAGE, PREVENTING PREVALENT CHRONIC DISEASES, SUCH AS DIABETES, CANCER AND CARDIOVASCULAR DISEASE. THE REPORTED WIDE RANGE OF EFFECTS THAT INCLUDED ANTI-AGING, ANTI-ATHEROSCLEROSIS, ANTI-INFLAMMATORY AND ANTICANCER ACTIVITY WERE STUDIED AGAINST DEGENERATIVE PATHOLOGIES OF THE BRAIN. VITAMINS AND DIFFERENT PHYTOCHEMICALS ARE IMPORTANT EPIGENETIC MODIFIERS THAT PREVENT NEURODEGENERATION. IN ORDER TO EXPLORE THE POTENTIAL ANTIOXIDANT SOURCES IN FUNCTIONAL FOODS AND NUTRACEUTICALS AGAINST NEURODEGENERATION, THE PRESENT PAPER AIMS TO SHOW A COMPREHENSIVE ASSESSMENT OF ANTIOXIDANT ACTIVITY AT CHEMICAL AND CELLULAR LEVELS. THE EFFECTS OF THE DIFFERENT BIOACTIVE COMPOUNDS AVAILABLE AND THEIR ANTIOXIDANT ACTIVITY THROUGH AN EPIGENETIC POINT OF VIEW ARE ALSO DISCUSSED. 2019 18 548 37 AUTISM SPECTRUM DISORDER AT THE CROSSROAD BETWEEN GENES AND ENVIRONMENT: CONTRIBUTIONS, CONVERGENCES, AND INTERACTIONS IN ASD DEVELOPMENTAL PATHOPHYSIOLOGY. THE COMPLEX PATHOPHYSIOLOGY OF AUTISM SPECTRUM DISORDER ENCOMPASSES INTERACTIONS BETWEEN GENETIC AND ENVIRONMENTAL FACTORS. ON THE ONE HAND, HUNDREDS OF GENES, CONVERGING AT THE FUNCTIONAL LEVEL ON SELECTIVE BIOLOGICAL DOMAINS SUCH AS EPIGENETIC REGULATION AND SYNAPTIC FUNCTION, HAVE BEEN IDENTIFIED TO BE EITHER CAUSATIVE OR RISK FACTORS OF AUTISM. ON THE OTHER HAND, EXPOSURE TO CHEMICALS THAT ARE WIDESPREAD IN THE ENVIRONMENT, SUCH AS ENDOCRINE DISRUPTORS, HAS BEEN ASSOCIATED WITH ADVERSE EFFECTS ON HUMAN HEALTH, INCLUDING NEURODEVELOPMENTAL DISORDERS. INTERESTINGLY, EXPERIMENTAL RESULTS SUGGEST AN OVERLAP IN THE REGULATORY PATHWAYS PERTURBED BY GENETIC MUTATIONS AND ENVIRONMENTAL FACTORS, DEPICTING CONVERGENCES AND COMPLEX INTERPLAYS BETWEEN GENETIC SUSCEPTIBILITY AND TOXIC INSULTS. THE PERVASIVE NATURE OF CHEMICAL EXPOSURE POSES PIVOTAL CHALLENGES FOR NEUROTOXICOLOGICAL STUDIES, REGULATORY AGENCIES, AND POLICY MAKERS. THIS HIGHLIGHTS AN EMERGING NEED OF DEVELOPING NEW INTEGRATIVE MODELS, INCLUDING BIOMONITORING, EPIDEMIOLOGY, EXPERIMENTAL, AND COMPUTATIONAL TOOLS, ABLE TO CAPTURE REAL-LIFE SCENARIOS ENCOMPASSING THE INTERACTION BETWEEN CHRONIC EXPOSURE TO MIXTURE OF SUBSTANCES AND INDIVIDUALS' GENETIC BACKGROUNDS. IN THIS REVIEW, WE ADDRESS THE INTERTWINED ROLES OF GENETIC LESIONS AND ENVIRONMENTAL INSULTS. SPECIFICALLY, WE OUTLINE THE TRANSFORMATIVE POTENTIAL OF STEM CELL MODELS, COUPLED WITH OMICS ANALYTICAL APPROACHES AT INCREASINGLY SINGLE CELL RESOLUTION, AS CONVERGING TOOLS TO EXPERIMENTALLY DISSECT THE PATHOGENIC MECHANISMS UNDERLYING NEURODEVELOPMENTAL DISORDERS, AS WELL AS TO IMPROVE DEVELOPMENTAL NEUROTOXICOLOGY RISK ASSESSMENT. 2020 19 2790 40 FACTORS TO CONSIDER IN THE USE OF STEM CELLS FOR PHARMACEUTIC DRUG DEVELOPMENT AND FOR CHEMICAL SAFETY ASSESSMENT. GIVEN THE REALITY OF THE INADEQUACIES OF CURRENT CONCEPTS OF THE MECHANISMS OF CHEMICAL TOXICITIES, OF THE VARIOUS ASSAYS TO PREDICT TOXICITIES FROM CURRENT MOLECULAR, BIOCHEMICAL, IN VITRO AND ANIMAL BIOASSAYS, AND OF THE FAILURE TO GENERATE EFFICACIOUS AND SAFE CHEMICALS FOR MEDICINES, FOOD SUPPLEMENTS, INDUSTRIAL, CONSUMER AND AGRICULTURAL CHEMICALS, THE RECENT NAS REPORT, "TOXICITY TESTING IN THE 21ST CENTURY: A VISION AND A STRATEGY", HAS DRAWN ATTENTION TO A RENEWED EXAMINATION OF WHAT NEEDS TO BE DONE TO IMPROVE OUR CURRENT APPROACH FOR BETTER ASSESSMENT OF POTENTIAL RISK TO HUMAN HEALTH. THIS "COMMENTARY" PROVIDES A MAJOR PARADIGM CHALLENGE TO THE CURRENT CONCEPTS OF HOW CHEMICALS INDUCE TOXICITIES AND HOW THESE VARIOUS MECHANISMS OF TOXICITIES CAN CONTRIBUTE TO THE PATHOGENESIS OF SOME HUMAN DISEASES, SUCH AS BIRTH DEFECTS AND CANCER. IN CONCORDANCE WITH THE NAS REPORT TO TAKE "... ADVANTAGE OF THE ON-GOING REVOLUTION IN BIOLOGY AND BIOTECHNOLOGY", THIS "COMMENTARY" SUPPORTS THE USE OF HUMAN EMBRYONIC AND ADULT STEM CELLS, GROWN IN VITRO UNDER SIMULATED "IN VIVO NICHE CONDITIONS". THE HUMAN BEING SHOULD BE VIEWED "AS GREATER THAN THE SUM OF ITS PARTS". HOMEOSTATIC CONTROL OF THE "EMERGENT PROPERTIES" OF THE HUMAN HIERARCHY, NEEDED TO MAINTAIN HUMAN HEALTH, REQUIRES COMPLEX INTEGRATION OF ENDOGENOUS AND EXOGENOUS SIGNALING MOLECULES THAT CONTROL CELL PROLIFERATION, DIFFERENTIATION, APOPTOSIS AND SENESCENCE OF STEM, PROGENITOR AND DIFFERENTIATED CELLS. CURRENTLY, IN VITRO TOXICITY ASSAYS (MUTAGENESIS, CYTOTOXICITY, EPIGENETIC MODULATION), DONE ON 2-DIMENSIONAL PRIMARY RODENT OR HUMAN CELLS (WHICH ARE ALWAYS MIXTURES OF CELLS), ON IMMORTALIZED OR TUMORIGENIC RODENT OR HUMAN CELL LINES DO NOT REPRESENT NORMAL HUMAN CELLS IN VIVO [WHICH DO NOT GROW ON PLASTIC AND WHICH ARE IN MICRO-ENVIRONMENTS REPRESENTING 3 DIMENSIONS AND CONSTANTLY INTERACTING FACTORS]. IN ADDITION, WITH THE KNOWN GENETIC, GENDER, AND DEVELOPMENTAL STATE OF CELLS IN VIVO, ANY IN VITRO TOXICITY ASSAY WILL NEED TO MIMIC THESE CONDITIONS IN VITRO. MORE SPECIFICALLY, WHILE TISSUES CONTAIN A FEW STEM CELLS, MANY PROGENITOR/TRANSIT CELLS AND TERMINALLY DIFFERENTIATED CELLS, IT SHOULD BE OBVIOUS THAT BOTH EMBRYONIC AND ADULT STEM CELLS WOULD BE CRITICAL "TARGET" CELLS FOR TOXICITY TESTING. THE ULTIMATE POTENTIAL FOR IN VITRO TESTING OF HUMAN STEM CELLS WILL TO TRY TO MIMIC A 3-D IN VITRO MICRO-ENVIRONMENT ON MULTIPLE "ORGAN-SPECIFIC AND MULTIPLE GENOTYPIC/GENDER "ADULT STEM CELLS. THE ROLE OF STEM CELLS IN MANY CHRONIC DISEASES, SUCH AS CANCER, BIRTH DEFECTS, AND POSSIBLY ADULT DISEASES AFTER PRE-NATAL AND EARLY POST-NATAL EXPOSURES (BARKER HYPOTHESIS), DEMANDS TOXICITY STUDIES OF STEM CELLS. WHILE ALTERATION OF GENE EXPRESSION ("TOXICO-EPIGENOMICS") IS A LEGITIMATE ENDPOINT OF THESE TOXICITY STUDIES, ALTERATION OF THE QUANTITY OF STEM CELLS DURING DEVELOPMENT MUST BE SERIOUS CONSIDERED. IF THE FUTURE UTILITY OF HUMAN STEM CELLS PROVES TO BE VALID, THE ELIMINATION OF LESS RELEVANT, EXPENSIVE AND TIME-CONSUMING RODENT AND 2-D HUMAN IN VITRO ASSAYS WILL BE ELIMINATED. 2010 20 1157 34 CONTAMINANT METALS AS CARDIOVASCULAR RISK FACTORS: A SCIENTIFIC STATEMENT FROM THE AMERICAN HEART ASSOCIATION. EXPOSURE TO ENVIRONMENTAL POLLUTANTS IS LINKED TO INCREASED RISK OF CARDIOVASCULAR DISEASE. BEYOND THE EXTENSIVE EVIDENCE FOR PARTICULATE AIR POLLUTION, ACCUMULATING EVIDENCE SUPPORTS THAT EXPOSURE TO NONESSENTIAL METALS SUCH AS LEAD, CADMIUM, AND ARSENIC IS A SIGNIFICANT CONTRIBUTOR TO CARDIOVASCULAR DISEASE WORLDWIDE. HUMANS ARE EXPOSED TO METALS THROUGH AIR, WATER, SOIL, AND FOOD AND EXTENSIVE INDUSTRIAL AND PUBLIC USE. CONTAMINANT METALS INTERFERE WITH CRITICAL INTRACELLULAR REACTIONS AND FUNCTIONS LEADING TO OXIDATIVE STRESS AND CHRONIC INFLAMMATION THAT RESULT IN ENDOTHELIAL DYSFUNCTION, HYPERTENSION, EPIGENETIC DYSREGULATION, DYSLIPIDEMIA, AND CHANGES IN MYOCARDIAL EXCITATION AND CONTRACTILE FUNCTION. LEAD, CADMIUM, AND ARSENIC HAVE BEEN LINKED TO SUBCLINICAL ATHEROSCLEROSIS, CORONARY ARTERY STENOSIS, AND CALCIFICATION AS WELL AS TO INCREASED RISK OF ISCHEMIC HEART DISEASE AND STROKE, LEFT VENTRICULAR HYPERTROPHY AND HEART FAILURE, AND PERIPHERAL ARTERY DISEASE. EPIDEMIOLOGICAL STUDIES SHOW THAT EXPOSURE TO LEAD, CADMIUM, OR ARSENIC IS ASSOCIATED WITH CARDIOVASCULAR DEATH MOSTLY ATTRIBUTABLE TO ISCHEMIC HEART DISEASE. PUBLIC HEALTH MEASURES REDUCING METAL EXPOSURE ARE ASSOCIATED WITH REDUCTIONS IN CARDIOVASCULAR DISEASE DEATH. POPULATIONS OF COLOR AND LOW SOCIOECONOMIC MEANS ARE MORE COMMONLY EXPOSED TO METALS AND THEREFORE AT GREATER RISK OF METAL-INDUCED CARDIOVASCULAR DISEASE. TOGETHER WITH STRENGTHENING PUBLIC HEALTH MEASURES TO PREVENT METAL EXPOSURES, DEVELOPMENT OF MORE SENSITIVE AND SELECTIVE MEASUREMENT MODALITIES, CLINICAL MONITORING OF METAL EXPOSURES, AND THE DEVELOPMENT OF METAL CHELATION THERAPIES COULD FURTHER DIMINISH THE BURDEN OF CARDIOVASCULAR DISEASE ATTRIBUTABLE TO METAL EXPOSURE. 2023