1 2808 149 FETAL PROGRAMMING OF HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS FUNCTION AND BEHAVIOR BY SYNTHETIC GLUCOCORTICOIDS. REDUCED FETAL GROWTH HAS BEEN CLOSELY ASSOCIATED WITH AN INCREASED RISK FOR THE DEVELOPMENT OF CHRONIC DISEASE IN LATER LIFE. ACCUMULATING EVIDENCE INDICATES THAT FETAL EXPOSURE TO EXCESS GLUCOCORTICOIDS REPRESENTS A CRITICAL MECHANISM UNDERLYING THIS ASSOCIATION. APPROXIMATELY 7% OF PREGNANT WOMEN ARE AT RISK OF PRETERM DELIVERY AND THESE WOMEN ARE ROUTINELY TREATED WITH SYNTHETIC GLUCOCORTICOIDS (SGC) BETWEEN 24 AND 34 OF WEEKS GESTATION TO IMPROVE NEONATAL OUTCOME. ANIMAL STUDIES HAVE DEMONSTRATED THAT MATERNALLY ADMINISTERED SGC CROSSES THE PLACENTA, AFFECTING FETAL HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) DEVELOPMENT, RESULTING IN CHANGES IN HPA AXIS FUNCTION THAT PERSIST THROUGHOUT LIFE. THESE CHANGES APPEAR TO BE MODULATED AT THE LEVEL OF GLUCOCORTICOID RECEPTORS (GR) AND MINERALOCORTICOID RECEPTORS (MR) IN THE BRAIN AND PITUITARY. AS THE HPA AXIS INTERACTS WITH MANY OTHER PHYSIOLOGICAL PATHWAYS, THE CHANGES IN ENDOCRINE FUNCTION ARE ALSO SEX-SPECIFIC AND AGE-DEPENDENT. ALTERATIONS IN BEHAVIOR, PARTICULARLY LOCOMOTION, IN ANIMALS EXPOSED TO SGC IN UTERO HAVE ALSO BEEN DEMONSTRATED. CONSISTENT WITH THE FINDING IN ANIMAL MODELS, EMERGING HUMAN DATA ARE INDICATING ATTENTION DEFICIT-HYPERACTIVITY DISORDER (ADHD)-LIKE SYMPTOMS IN CHILDREN EXPOSED TO REPEATED COURSES OF SGC IN UTERO. THIS BEHAVIORAL PHENOTYPE IS LIKELY LINKED TO ALTERATIONS IN DOPAMINE (DA) SIGNALING, SUGGESTING THAT SGC ARE ABLE TO PERMANENTLY MODIFY OR 'PROGRAM' THIS SYSTEM. FINALLY, IT IS EMERGING THAT CHANGES IN HPA AXIS FUNCTION AND BEHAVIOR FOLLOWING ANTENATAL EXPOSURE TO SGC ARE TRANSGENERATIONAL AND LIKELY INVOLVE EPIGENETIC MECHANISMS. A COMPREHENSIVE UNDERSTANDING OF THE ACUTE AND LONG-TERM IMPACT OF SGC EXPOSURE IN UTERO IS NECESSARY TO BEGIN TO DEVELOP RECOMMENDATIONS AND TREATMENT OPTIONS FOR PREGNANT WOMEN AT RISK OF PRETERM DELIVERY. 2008 2 6853 46 [NEUROBIOLOGY OF EARLY LIFE TRAUMATIC STRESS AND TRAUMA: PROLONGED NEUROENDOCRINE DYSREGULATION AS A NEURODEVELOPMENTAL RISK FACTOR]. EARLY LIFE STRESSORS DISPLAY A HIGH UNIVERSAL PREVALENCE AND CONSTITUTE A MAJOR PUBLIC HEALTH PROBLEM WITH TWO THIRDS OF YOUTH BEING EXPOSED TO POTENTIALLY TRAUMATIC EXPERIENCES BY THE AGE OF 17. TRAUMATIC STRESS EXPOSURE DURING CRITICAL PERIODS OF DEVELOPMENT MAY HAVE ESSENTIAL AND LONG-LASTING EFFECTS ON THE PHYSICAL AND MENTAL HEALTH OF INDIVIDUALS AND REPRESENTS A DEVELOPMENTAL RISK FACTOR MEDIATING RISK FOR DISEASE. EARLY-LIFE STRESS (ELS) AND CHILDHOOD TRAUMA (CT) CAN BOTH HAVE AN IMPACT ON SENSITIVE NEURONAL BRAIN NETWORKS INVOLVED IN STRESS REACTIONS, AND COULD EXERT A PROGRAMMING EFFECT ON GLUCOCORTICOID SIGNALING LEADING TO CHRONIC HYPER- OR HYPO-ACTIVATION OF THE STRESS SYSTEM. IN ADDITION, ALTERATIONS IN EMOTIONAL AND AUTONOMIC REACTIVITY, CIRCADIAN RHYTHM DISRUPTION, FUNCTIONAL AND STRUCTURAL CHANGES IN THE BRAIN, AS WELL AS IMMUNE AND METABOLIC DYSREGULATION HAVE BEEN LATELY IDENTIFIED AS IMPORTANT RISK FACTORS FOR A CHRONICALLY IMPAIRED HOMEOSTATIC BALANCE AFTER ELS/CT. FURTHERMORE, HUMAN GENETIC BACKGROUND AND EPIGENETIC MODIFICATIONS THROUGH STRESS-RELATED GENE EXPRESSION COULD INTERACT WITH THESE ALTERATIONS AND EXPLAIN INTER-INDIVIDUAL VARIATION IN VULNERABILITY OR RESILIENCE TO STRESS. THIS NARRATIVE REVIEW PRESENTS RELEVANT EVIDENCE FROM MAINLY HUMAN RESEARCH ON THE MOST ACKNOWLEDGED NEUROBIOLOGICAL ALLOSTATIC PATHWAYS EXERTING ENDURING ADVERSE EFFECTS OF ELS/CT EVEN DECADES LATER. FUTURE STUDIES SHOULD PROSPECTIVELY INVESTIGATE POTENTIAL CONFOUNDERS, THEIR TEMPORAL SEQUENCE AND COMBINED EFFECTS AT THE BIOLOGICAL LEVEL, WHILE CONSIDERING THE POTENTIALLY DELAYED TIME-FRAME FOR THE EXPRESSION OF THEIR EFFECTS. FINALLY, SCREENING STRATEGIES FOR ELS/CT AND TRAUMA NEED TO BE IMPROVED. INFORMATION ABOUT ELS/CT HISTORY AND THE NUMBER OF ADVERSE EXPERIENCES COULD HELP TO BETTER IDENTIFY THE INDIVIDUAL RISK FOR DISEASE DEVELOPMENT, PREDICT INDIVIDUAL TREATMENT RESPONSE AND DESIGN PREVENTION STRATEGIES TO REDUCE THE NEGATIVE EFFECTS OF ELS/CT. 2023 3 4999 39 PERINATAL PROGRAMMING OF CIRCADIAN CLOCK-STRESS CROSSTALK. AN INTACT COMMUNICATION BETWEEN CIRCADIAN CLOCKS AND THE STRESS SYSTEM IS IMPORTANT FOR MAINTAINING PHYSIOLOGICAL HOMEOSTASIS UNDER RESTING CONDITIONS AND IN RESPONSE TO EXTERNAL STIMULI. THERE IS ACCUMULATING EVIDENCE FOR A RECIPROCAL INTERACTION BETWEEN BOTH-FROM THE SYSTEMIC TO THE MOLECULAR LEVEL. DISRUPTION OF THIS INTERACTION BY EXTERNAL FACTORS SUCH AS SHIFTWORK, JETLAG, OR CHRONIC STRESS INCREASES THE RISK OF DEVELOPING METABOLIC, IMMUNE, OR MOOD DISORDERS. FROM EXPERIMENTS IN RODENTS, WE KNOW THAT BOTH SYSTEMS MATURATE DURING THE PERINATAL PERIOD. DURING THAT TIME, EXOGENOUS FACTORS SUCH AS STRESS OR ALTERATIONS IN THE EXTERNAL PHOTOPERIOD MAY CRITICALLY AFFECT-OR PROGRAM-PHYSIOLOGICAL FUNCTIONS LATER IN LIFE. THIS DEVELOPMENTAL PROGRAMMING PROCESS HAS BEEN ATTRIBUTED TO MATERNAL STRESS SIGNALS REACHING THE EMBRYO, WHICH LASTINGLY CHANGE GENE EXPRESSION THROUGH THE INDUCTION OF EPIGENETIC MECHANISMS. DESPITE THE WELL-KNOWN FUNCTION OF THE ADULT CIRCADIAN SYSTEM IN TEMPORAL COORDINATION OF PHYSIOLOGY AND BEHAVIOR, THE ROLE OF MATERNAL AND EMBRYONIC CIRCADIAN CLOCKS DURING PREGNANCY AND POSTNATAL DEVELOPMENT IS STILL POORLY DEFINED. A BETTER UNDERSTANDING OF THE CIRCADIAN-STRESS CROSSTALK AT DIFFERENT PERIODS OF DEVELOPMENT MAY HELP TO IMPROVE STRESS RESISTANCE AND DEVISE PREVENTIVE AND THERAPEUTIC STRATEGIES AGAINST CHRONIC STRESS-ASSOCIATED DISORDERS. 2018 4 1749 35 EARLY LIFE INTERVENTIONS CAN SHAPE AGING. IT IS WELL DOCUMENTED THAT THE ENVIRONMENT OF THE DEVELOPING FETUS, INCLUDING AVAILABILITY OF NUTRIENTS AND PRESENCE OF TOXINS, CAN HAVE MAJOR IMPACT ON ADULT PHENOTYPE, AGE-RELATED TRAITS AND RISK OF CHRONIC DISEASE. THERE IS ALSO ACCUMULATING EVIDENCE THAT POSTNATAL ENVIRONMENT CAN IMPACT ADULT CHARACTERISTICS RELATED TO EVOLUTIONARY FITNESS, HEALTH, AND AGING. TO DETERMINE WHETHER EARLY LIFE HORMONAL INTERVENTIONS CAN ALTER TRAJECTORY OF AGING, WE HAVE EXAMINED THE EFFECTS OF EARLY LIFE GROWTH HORMONE (GH) REPLACEMENT THERAPY IN PROP1(DF) (AMES DWARF) MICE WHICH ARE GH DEFICIENT AND REMARKABLY LONG LIVED. TWICE-DAILY GH INJECTIONS BETWEEN THE AGES OF TWO AND EIGHT WEEKS COMPLETELY NORMALIZED ("RESCUED") A NUMBER OF ADULT METABOLIC CHARACTERISTICS BELIEVED TO CONTRIBUTE TO EXTENDED LONGEVITY OF THESE MUTANTS. IMPORTANTLY, LONGEVITY OF AMES DWARF MICE WAS REDUCED BY EARLY LIFE GH TREATMENT. THIS WAS ASSOCIATED WITH HISTONE H3 MODIFICATIONS. WE CONCLUDE THAT THE TRAJECTORY OF MAMMALIAN AGING CAN BE MODIFIED BY EARLY LIFE INTERVENTIONS. MECHANISTIC LINKS AMONG INTERVENTIONS DURING POSTNATAL DEVELOPMENT, ADULT METABOLIC CHARACTERISTICS, AGING, AND LONGEVITY, APPARENTLY INVOLVE EPIGENETIC PHENOMENA. 2022 5 5810 34 STRESS & SLEEP: A RELATIONSHIP LASTING A LIFETIME. STRESS IS AN ADAPTATIVE RESPONSE AIMED AT RESTORING BODY HOMEOSTASIS. THE CLASSICAL NEUROENDOCRINE STRESS RESPONSE INVOLVING THE ACTIVATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS MODULATES MANY PHYSIOLOGICAL ASPECTS, SUCH AS THE WAKE-SLEEP CYCLE. IN THE PRESENT REVIEW, WE WILL FIRST REPORT A SERIES OF HUMAN AND RODENT STUDIES SHOWING THAT EACH ACTOR OF THE HPA AXIS HAS THE POTENTIAL TO INTERFERE WITH SLEEP HOMEOSTASIS AND, THEN, WE WILL HIGHLIGHT HOW ACUTE OR CHRONIC STRESS DIFFERENTLY MODULATES THE WAKE-SLEEP CYCLE. MOREOVER, WE WILL PRESENT NEW AND INTERESTING STUDIES DEALING WITH THE RELATIONSHIP BETWEEN SLEEP AND STRESS ON A DIFFERENT (LONGER) TIME SCALE. PARTICULARLY, WE WILL DISCUSS HOW THE EXPOSURE TO PERINATAL STRESS, PROBABLY THROUGH EPIGENETIC MODULATIONS, IS SUFFICIENT TO CAUSE PERSISTENT SLEEP DERANGEMENTS DURING ADULT LIFE. IN LIGHT OF THIS EVIDENCE, THE MAIN MESSAGE OF THE PRESENT REVIEW IS THAT THE COMPLEX RELATIONSHIP BETWEEN SLEEP AND STRESS CHANGES DRAMATICALLY ON THE BASIS OF THE TIME SCALE CONSIDERED AND, CONSEQUENTLY, "TIME" SHOULD BE CONSIDERED AS A CRITICAL FACTOR WHEN FACING THIS TOPIC. 2020 6 678 42 BRAIN DEVELOPMENT UNDER STRESS: HYPOTHESES OF GLUCOCORTICOID ACTIONS REVISITED. ONE OF THE CONUNDRUMS IN TODAY'S STRESS RESEARCH IS WHY SOME INDIVIDUALS FLOURISH AND OTHERS PERISH UNDER SIMILAR STRESSFUL CONDITIONS. IT IS RECOGNIZED THAT THIS INDIVIDUAL VARIABILITY IN ADAPTATION TO STRESS DEPENDS ON THE OUTCOME OF THE INTERACTION OF GENETIC AND COGNITIVE/EMOTIONAL INPUTS IN WHICH GLUCOCORTICOID HORMONES AND RECEPTORS PLAY A CRUCIAL ROLE. HENCE ONE APPROACH TOWARDS UNDERSTANDING INDIVIDUAL VARIATION IN STRESS COPING IS HOW GLUCOCORTICOID ACTIONS CAN CHANGE FROM PROTECTIVE TO HARMFUL. TO ADDRESS THIS QUESTION WE FOCUS ON FOUR HYPOTHESES THAT ARE CONNECTED AND NOT MUTUAL EXCLUSIVE. FIRST, THE CLASSICAL GLUCOCORTICOID CASCADE HYPOTHESIS, IN WHICH THE INABILITY TO COPE WITH CHRONIC STRESS CAUSES A VICIOUS CYCLE OF EXCESS GLUCOCORTICOID AND DOWNREGULATION OF GLUCOCORTICOID RECEPTORS (GR) IN THE HIPPOCAMPUS TRIGGERING A FEED-FORWARD CASCADE OF DEGENERATION AND DISEASE. SECOND, THE BALANCE HYPOTHESIS, WHICH TAKES ALSO THE LIMBIC MINERALOCORTICOID RECEPTORS (MR) INTO ACCOUNT AND PROPOSES THAT AN INTEGRAL LIMBIC MR:GR IMBALANCE IS CAUSAL TO ALTERED PROCESSING OF INFORMATION IN CIRCUITS UNDERLYING FEAR, REWARD, SOCIAL BEHAVIOUR AND RESILIENCE, DYSREGULATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS AND IMPAIRMENT OF BEHAVIOURAL ADAPTATION. THE MR:GR BALANCE IS ALTERED BY GENE VARIANTS OF THESE RECEPTOR COMPLEXES AND EXPERIENCE-RELATED FACTORS, WHICH CAN INDUCE LASTING EPIGENETIC CHANGES IN THE EXPRESSION OF THESE RECEPTORS. A PARTICULAR POTENT EPIGENETIC STIMULUS IS THE MATERNAL ENVIRONMENT WHICH IS FUNDAMENTAL FOR THE MATERNAL MEDIATION HYPOTHESIS. THE OUTCOME OF PERINATAL GENE X ENVIRONMENT INTERACTION, AND THUS OF MR:GR-MEDIATED FUNCTIONS DEPENDS HOWEVER, ON THE DEGREE OF 'MATCHING' WITH ENVIRONMENTAL DEMANDS IN LATER LIFE. THE PREDICTIVE ADAPTATION HYPOTHESIS THEREFORE PRESENTS A CONCEPTUAL FRAMEWORK TO EXAMINE THE ROLE OF GLUCOCORTICOIDS IN UNDERSTANDING INDIVIDUAL PHENOTYPIC DIFFERENCES IN STRESS-RELATED BEHAVIOURS OVER THE LIFESPAN. 2010 7 5160 42 PREADOLESCENT ADVERSITY PROGRAMS A DISRUPTED MATERNAL STRESS REACTIVITY IN HUMANS AND MICE. BACKGROUND: ADVERSE CHILDHOOD EXPERIENCES (ACES) ARE ONE OF THE GREATEST PREDICTORS OF AFFECTIVE DISORDERS FOR WOMEN. PERIODS OF DYNAMIC HORMONAL FLUX, INCLUDING PREGNANCY, EXACERBATE THE RISK FOR AFFECTIVE DISTURBANCE AND PROMOTE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS DYSREGULATION, A KEY FEATURE OF AFFECTIVE DISORDERS. LITTLE IS UNDERSTOOD AS TO HOW STRESS EXPERIENCED IN LATE CHILDHOOD, DEFINED AS PREADOLESCENCE, ALTERS THE PROGRAMMING UNIQUE TO THIS PERIOD OF BRAIN MATURATION AND ITS INTERACTION WITH THE HORMONAL CHANGES OF PREGNANCY AND POSTPARTUM. METHODS: PREADOLESCENT FEMALE MICE WERE EXPOSED TO CHRONIC STRESS AND EXAMINED FOR CHANGES IN THEIR HPA AXIS DURING PREGNANCY AND POSTPARTUM, INCLUDING ASSESSMENT OF MATERNAL-SPECIFIC STRESS RESPONSIVENESS AND TRANSCRIPTOMICS OF THE PARAVENTRICULAR NUCLEUS OF THE HYPOTHALAMUS. TRANSLATIONALLY, PREGNANT WOMEN WITH LOW OR HIGH ACES WERE EXAMINED FOR THEIR MATERNAL STRESS RESPONSIVENESS. RESULTS: AS PREDICTED, PREADOLESCENT STRESS IN MICE RESULTED IN A SIGNIFICANT BLUNTING OF THE CORTICOSTERONE RESPONSE DURING PREGNANCY. TRANSCRIPTOMIC ANALYSIS OF THE PARAVENTRICULAR NUCLEUS REVEALED WIDESPREAD CHANGES IN EXPRESSION OF IMMEDIATE EARLY GENES AND THEIR TARGETS, SUPPORTING THE LIKELY INVOLVEMENT OF AN UPSTREAM EPIGENETIC MECHANISM. CRITICALLY, IN OUR HUMAN STUDIES, THE HIGH ACE WOMEN SHOWED A SIGNIFICANT BLUNTING OF THE HPA RESPONSE. CONCLUSIONS: THIS UNIQUE MOUSE MODEL RECAPITULATES A CLINICAL OUTCOME OF A HYPORESPONSIVE HPA STRESS AXIS, AN IMPORTANT FEATURE OF AFFECTIVE DISORDERS, DURING A DYNAMIC HORMONAL PERIOD, AND SUGGESTS INVOLVEMENT OF TRANSCRIPTIONAL REGULATION IN THE HYPOTHALAMUS. THESE STUDIES IDENTIFY A NOVEL MOUSE MODEL OF FEMALE ACES THAT CAN BE USED TO EXAMINE HOW ADDITIONAL LIFE ADVERSITY MAY PROVOKE DISEASE RISK OR RESILIENCE. 2017 8 1639 27 DOES EPIGENETIC 'MEMORY' OF EARLY-LIFE STRESS PREDISPOSE TO CHRONIC PAIN IN LATER LIFE? A POTENTIAL ROLE FOR THE STRESS REGULATOR FKBP5. ANIMAL BEHAVIOURS ARE AFFECTED NOT ONLY BY INHERITED GENES BUT ALSO BY ENVIRONMENTAL EXPERIENCES. FOR EXAMPLE, IN BOTH RATS AND HUMANS, STRESSFUL EARLY-LIFE EVENTS SUCH AS BEING REARED BY AN INATTENTIVE MOTHER CAN LEAVE A LASTING TRACE AND AFFECT LATER STRESS RESPONSE IN ADULT LIFE. THIS IS OWING TO A CHEMICAL TRACE LEFT ON THE CHROMATIN ATTRIBUTED TO SO-CALLED EPIGENETIC MECHANISMS. SUCH AN EPIGENETIC TRACE OFTEN HAS CONSEQUENCES, SOMETIMES LONG-LASTING, ON THE FUNCTIONING OF OUR GENES, THEREBY ALLOWING INDIVIDUALS TO RAPIDLY ADAPT TO A NEW ENVIRONMENT. ONE GENE UNDER SUCH EPIGENETIC CONTROL IS FKBP5, THE GENE THAT ENCODES THE PROTEIN FKPB51, A CRUCIAL REGULATOR OF THE STRESS AXIS AND A SIGNIFICANT DRIVER OF CHRONIC PAIN STATES. IN THIS ARTICLE, WE WILL DISCUSS THE POSSIBILITY THAT EXPOSURE TO STRESS COULD DRIVE THE SUSCEPTIBLY TO CHRONIC PAIN VIA EPIGENETIC MODIFICATIONS OF GENES WITHIN THE STRESS AXIS SUCH AS FKBP5. THE POSSIBILITY THAT SUCH MODIFICATIONS, AND THEREFORE, THE SUSCEPTIBILITY TO CHRONIC PAIN, COULD BE TRANSMITTED ACROSS GENERATIONS IN MAMMALS AND WHETHER SUCH MECHANISMS MAY BE EVOLUTIONARILY CONSERVED ACROSS PHYLA WILL ALSO BE DEBATED. THIS ARTICLE IS PART OF THE THEO MURPHY MEETING ISSUE 'EVOLUTION OF MECHANISMS AND BEHAVIOUR IMPORTANT FOR PAIN'. 2019 9 1774 35 EARLY-LIFE STRESS: FROM NEUROENDOCRINE MECHANISMS TO STRESS-RELATED DISORDERS. STRESS EXPOSURE IS HIGHLY PREVALENT IN THE GENERAL POPULATION; HOWEVER, THE EXPERIENCE OF STRESS DURING VULNERABLE PERIODS OF DEVELOPMENT HAS SUBSTANTIAL AND PERMANENT EFFECTS ON BRAIN STRUCTURE AND FUNCTION AND PHYSICAL HEALTH IN ADULTHOOD. STRESS, THE STATE OF THREATENED HOMEOSTASIS, IS GENERALLY ASSOCIATED WITH A TIME-LIMITED ACTIVATION OF THE STRESS SYSTEM, I.E., THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS AND THE AROUSAL/SYMPATHETIC NERVOUS SYSTEM, TAILORED TO THE STRESSFUL STIMULUS ALSO KNOWN AS THE STRESSOR. ON THE OTHER HAND, CHRONIC STRESS MAY BE ASSOCIATED WITH LINGERING HYPER- OR HYPOSECRETION OF MEDIATORS OF THE STRESS SYSTEM. THIS CHRONIC CONDITION IS CALLED DYSHOMEOSTASIS, ALLOSTASIS, OR CACOSTASIS AND IS ASSOCIATED WITH INCREASED MENTAL AND PHYSICAL MORBIDITY IN THE LONG TERM. STRESSFUL OR TRAUMATIC EXPERIENCES DURING FETAL LIFE, EARLY CHILDHOOD, AND ADOLESCENCE HAVE BEEN RELATED TO PERSISTENT NEUROENDOCRINE AND EPIGENETIC CHANGES. FURTHER, BRAIN STRUCTURES INVOLVED IN THE STRESS RESPONSE, SUCH AS THOSE OF THE STRESS SYSTEM, THE HIPPOCAMPUS, AND THE AMYGDALA, MAY BE PROGRAMMED EARLY ON FOR A LIFE OF ADVERSITY. 2018 10 1364 44 DEVELOPMENTAL NEUROENDOCRINOLOGY OF EARLY-LIFE STRESS: IMPACT ON CHILD DEVELOPMENT AND BEHAVIOR. OUR INTERNAL BALANCE, OR HOMEOSTASIS, IS THREATENED OR PERCEIVED AS THREATENED BY STRESSFUL STIMULI, THE STRESSORS. THE STRESS SYSTEM IS A HIGHLY CONSERVED SYSTEM THAT ADJUSTS HOMEOSTASIS TO THE RESTING STATE. THROUGH THE CONCURRENT ACTIVATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS AND THE LOCUS COERULEUS/NOREPINEPHRINE-AUTONOMIC NERVOUS SYSTEMS, THE STRESS SYSTEM PROVIDES THE APPROPRIATE PHYSICAL AND BEHAVIORAL RESPONSES, COLLECTIVELY TERMED AS "STRESS RESPONSE", TO RESTORE HOMEOSTASIS. IF THE STRESS RESPONSE IS PROLONGED, EXCESSIVE OR EVEN INADEQUATE, SEVERAL ACUTE OR CHRONIC STRESS-RELATED PATHOLOGIC CONDITIONS MAY DEVELOP IN CHILDHOOD, ADOLESCENCE AND ADULT LIFE. ON THE OTHER HAND, EARLY-LIFE EXPOSURE TO STRESSORS HAS BEEN RECOGNIZED AS A MAJOR CONTRIBUTING FACTOR UNDERLYING THE PATHOGENESIS OF NON-COMMUNICABLE DISORDERS, INCLUDING NEURODEVELOPMENTAL DISORDERS. ACCUMULATING EVIDENCE SUGGESTS THAT EARLY-LIFE STRESS HAS BEEN ASSOCIATED WITH AN INCREASED RISK FOR ATTENTION DEFICIT HYPERACTIVITY DISORDER AND AUTISM SPECTRUM DISORDER IN THE OFFSPRING, ALTHOUGH FINDINGS ARE STILL CONTROVERSIAL. NEVERTHELESS, AT THE MOLECULAR LEVEL, EARLY-LIFE STRESSORS ALTER THE CHEMICAL STRUCTURE OF CYTOSINES LOCAT- ED IN THE REGULATORY REGIONS OF GENES, MOSTLY THROUGH THE ADDITION OF METHYL GROUPS. THESE EPIGENETIC MODIFICATIONS RESULT IN THE SUPPRESSION OF GENE EXPRESSION WITHOUT CHANGING THE DNA SEQUENCE. IN ADDITION TO DNA METHYLATION, SEVERAL LINES OF EVIDENCE SUPPORT THE ROLE OF NON-CODING RNAS IN THE EVOLVING FIELD OF EPIGENETICS. IN THIS REVIEW ARTICLE, WE PRESENT THE ANATOMICAL AND FUNCTIONAL COMPO- NENTS OF THE STRESS SYSTEM, DISCUSS THE PROPER, IN TERMS OF QUALITY AND QUANTITY, STRESS RESPONSE, AND PROVIDE AN UPDATE ON THE IMPACT OF EARLY-LIFE STRESS ON CHILD DEVELOPMENT AND BEHAVIOR. 2023 11 2471 30 EPIGENETIC TRANSGENERATIONAL INHERITANCE OF ALTERED STRESS RESPONSES. ANCESTRAL ENVIRONMENTAL EXPOSURES HAVE PREVIOUSLY BEEN SHOWN TO PROMOTE EPIGENETIC TRANSGENERATIONAL INHERITANCE AND INFLUENCE ALL ASPECTS OF AN INDIVIDUAL'S LIFE HISTORY. IN ADDITION, PROXIMATE LIFE EVENTS SUCH AS CHRONIC STRESS HAVE DOCUMENTED EFFECTS ON THE DEVELOPMENT OF PHYSIOLOGICAL, NEURAL, AND BEHAVIORAL PHENOTYPES IN ADULTHOOD. WE USED A SYSTEMS BIOLOGY APPROACH TO INVESTIGATE IN MALE RATS THE INTERACTION OF THE ANCESTRAL MODIFICATIONS CARRIED TRANSGENERATIONALLY IN THE GERM LINE AND THE PROXIMATE MODIFICATIONS INVOLVING CHRONIC RESTRAINT STRESS DURING ADOLESCENCE. WE FIND THAT A SINGLE EXPOSURE TO A COMMON-USE FUNGICIDE (VINCLOZOLIN) THREE GENERATIONS REMOVED ALTERS THE PHYSIOLOGY, BEHAVIOR, METABOLIC ACTIVITY, AND TRANSCRIPTOME IN DISCRETE BRAIN NUCLEI IN DESCENDANT MALES, CAUSING THEM TO RESPOND DIFFERENTLY TO CHRONIC RESTRAINT STRESS. THIS ALTERATION OF BASELINE BRAIN DEVELOPMENT PROMOTES A CHANGE IN NEURAL GENOMIC ACTIVITY THAT CORRELATES WITH CHANGES IN PHYSIOLOGY AND BEHAVIOR, REVEALING THE INTERACTION OF GENETICS, ENVIRONMENT, AND EPIGENETIC TRANSGENERATIONAL INHERITANCE IN THE SHAPING OF THE ADULT PHENOTYPE. THIS IS AN IMPORTANT DEMONSTRATION IN AN ANIMAL THAT ANCESTRAL EXPOSURE TO AN ENVIRONMENTAL COMPOUND MODIFIES HOW DESCENDANTS OF THESE PROGENITOR INDIVIDUALS PERCEIVE AND RESPOND TO A STRESS CHALLENGE EXPERIENCED DURING THEIR OWN LIFE HISTORY. 2012 12 4995 35 PERINATAL ENVIRONMENT AND ITS INFLUENCES ON METABOLIC PROGRAMMING OF OFFSPRING. THE INTRAUTERINE ENVIRONMENT SUPPORTS THE DEVELOPMENT AND HEALTH OF OFFSPRING. PERTURBATIONS TO THIS ENVIRONMENT CAN HAVE DETRIMENTAL EFFECTS ON THE FETUS THAT HAVE PERSISTENT PATHOLOGICAL CONSEQUENCES THROUGH ADOLESCENCE AND ADULTHOOD. THE DEVELOPMENTAL ORIGINS OF THE HEALTH AND DISEASE CONCEPT, ALSO KNOWN AS THE "BARKER HYPOTHESIS", HAS BEEN PUT FORTH TO DESCRIBE THE INCREASED INCIDENCE OF CHRONIC DISEASE SUCH AS CARDIOVASCULAR DISEASE AND DIABETES IN HUMANS AND ANIMALS EXPOSED TO A LESS THAN IDEAL INTRAUTERINE ENVIRONMENT. MATERNAL INFECTION, POOR OR EXCESS NUTRITION, AND STRESSFUL EVENTS CAN NEGATIVELY INFLUENCE THE DEVELOPMENT OF DIFFERENT CELL TYPES, TISSUES AND ORGAN SYSTEMS ULTIMATELY PREDISPOSING THE ORGANISM TO PATHOLOGICAL CONDITIONS. ALTHOUGH THERE ARE A VARIETY OF CONDITIONS ASSOCIATED TO EXPOSURE TO ALTERED INTRAUTERINE ENVIRONMENTS, THE FOCUS OF THIS REVIEW WILL BE ON THE CONSEQUENCES OF STRESS AND HIGH FAT DIET DURING THE PRE- AND PERINATAL PERIODS AND ASSOCIATED OUTCOMES RELATED TO OBESITY AND OTHER METABOLIC CONDITIONS. WE FURTHER DISCUSS POSSIBLE NEUROENDOCRINE AND EPIGENETIC MECHANISMS RESPONSIBLE FOR THE METABOLIC PROGRAMMING OF OFFSPRING. THE PAPER REPRESENTS AN INVITED REVIEW BY A SYMPOSIUM, AWARD WINNER OR KEYNOTE SPEAKER AT THE SOCIETY FOR THE STUDY OF INGESTIVE BEHAVIOR [SSIB] ANNUAL MEETING IN PORTLAND, JULY 2009. 2010 13 1162 27 CONTRASTING EFFECTS OF ACUTE AND CHRONIC STRESS ON THE TRANSCRIPTOME, EPIGENOME, AND IMMUNE RESPONSE OF ATLANTIC SALMON. STRESS EXPERIENCED DURING EARLY LIFE MAY HAVE LASTING EFFECTS ON THE IMMUNE SYSTEM, WITH IMPACTS ON HEALTH AND DISEASE DEPENDENT ON THE NATURE AND DURATION OF THE STRESSOR. THE EPIGENOME IS ESPECIALLY SENSITIVE TO ENVIRONMENTAL STIMULI DURING EARLY LIFE AND REPRESENTS A POTENTIAL MECHANISM THROUGH WHICH STRESS MAY CAUSE LONG-LASTING HEALTH EFFECTS. HOWEVER, THE EXTENT TO WHICH THE EPIGENOME RESPONDS DIFFERENTLY TO CHRONIC VS ACUTE STRESSORS IS UNCLEAR, ESPECIALLY FOR NON-MAMMALIAN SPECIES. WE EXAMINED THE EFFECTS OF ACUTE STRESS (COLD-SHOCK DURING EMBRYOGENESIS) AND CHRONIC STRESS (ABSENCE OF TANK ENRICHMENT DURING LARVAL-STAGE) ON GLOBAL GENE EXPRESSION (USING RNA-SEQ) AND DNA METHYLATION (USING RRBS) IN THE GILLS OF ATLANTIC SALMON (SALMO SALAR) FOUR MONTHS AFTER HATCHING. CHRONIC STRESS INDUCED PRONOUNCED TRANSCRIPTIONAL DIFFERENCES, WHILE ACUTE STRESS CAUSED FEW LASTING TRANSCRIPTIONAL EFFECTS. HOWEVER, BOTH ACUTE AND CHRONIC STRESS CAUSED LASTING AND CONTRASTING CHANGES IN THE METHYLOME. CRUCIALLY, WE FOUND THAT ACUTE STRESS ENHANCED TRANSCRIPTIONAL IMMUNE RESPONSE TO A PATHOGENIC CHALLENGE (BACTERIAL LIPOPOLYSACCHARIDE, LPS), WHILE CHRONIC STRESS SUPPRESSED IT. WE IDENTIFIED STRESS-INDUCED CHANGES IN PROMOTER AND GENE-BODY METHYLATION THAT WERE ASSOCIATED WITH ALTERED EXPRESSION FOR A SMALL PROPORTION OF IMMUNE-RELATED GENES, AND EVIDENCE OF WIDER EPIGENETIC REGULATION WITHIN SIGNALLING PATHWAYS INVOLVED IN IMMUNE RESPONSE. OUR RESULTS SUGGEST THAT STRESS CAN AFFECT IMMUNO-COMPETENCE THROUGH EPIGENETIC MECHANISMS, AND HIGHLIGHT THE MARKEDLY DIFFERENT EFFECTS OF CHRONIC LARVAL AND ACUTE EMBRYONIC STRESS. THIS KNOWLEDGE COULD BE USED TO HARNESS THE STIMULATORY EFFECTS OF ACUTE STRESS ON IMMUNITY, PAVING THE WAY FOR IMPROVED STRESS AND DISEASE MANAGEMENT THROUGH EPIGENETIC CONDITIONING. 2018 14 5705 28 SINGLE-CELL TRANSCRIPTIONAL CHANGES IN HYPOTHALAMIC CORTICOTROPIN-RELEASING FACTOR-EXPRESSING NEURONS AFTER EARLY-LIFE ADVERSITY INFORM ENDURING ALTERATIONS IN VULNERABILITIES TO STRESS. BACKGROUND: MENTAL HEALTH AND VULNERABILITIES TO NEUROPSYCHIATRIC DISORDERS INVOLVE THE INTERPLAY OF GENES AND ENVIRONMENT, PARTICULARLY DURING SENSITIVE DEVELOPMENTAL PERIODS. EARLY-LIFE ADVERSITY (ELA) AND STRESS PROMOTE VULNERABILITIES TO STRESS-RELATED AFFECTIVE DISORDERS, YET IT IS UNKNOWN HOW TRANSIENT ELA DICTATES LIFELONG NEUROENDOCRINE AND BEHAVIORAL REACTIONS TO STRESS. THE POPULATION OF HYPOTHALAMIC CORTICOTROPIN-RELEASING FACTOR (CRF)-EXPRESSING NEURONS THAT REGULATE STRESS RESPONSES IS A PROMISING CANDIDATE TO MEDIATE THE LONG-LASTING INFLUENCES OF ELA ON STRESS-RELATED BEHAVIORAL AND HORMONAL RESPONSES VIA ENDURING TRANSCRIPTIONAL AND EPIGENETIC MECHANISMS. METHODS: CAPITALIZING ON A WELL-CHARACTERIZED MODEL OF ELA, WE EXAMINED ELA-INDUCED CHANGES IN GENE EXPRESSION PROFILES OF CRF-EXPRESSING NEURONS IN THE HYPOTHALAMIC PARAVENTRICULAR NUCLEUS OF DEVELOPING MALE MICE. WE USED SINGLE-CELL RNA SEQUENCING ON ISOLATED CRF-EXPRESSING NEURONS. WE DETERMINED THE ENDURING FUNCTIONAL CONSEQUENCES OF TRANSCRIPTIONAL CHANGES ON STRESS REACTIVITY IN ADULT ELA MICE, INCLUDING HORMONAL RESPONSES TO ACUTE STRESS, ADRENAL WEIGHTS AS A MEASURE OF CHRONIC STRESS, AND BEHAVIORS IN THE LOOMING SHADOW THREAT TASK. RESULTS: SINGLE-CELL TRANSCRIPTOMICS IDENTIFIED DISTINCT AND NOVEL CRF-EXPRESSING NEURONAL POPULATIONS, CHARACTERIZED BY BOTH THEIR GENE EXPRESSION REPERTOIRE AND THEIR NEUROTRANSMITTER PROFILES. ELA-PROVOKED EXPRESSION CHANGES WERE SELECTIVE TO SPECIFIC SUBPOPULATIONS AND AFFECTED GENES INVOLVED IN NEURONAL DIFFERENTIATION, SYNAPSE FORMATION, ENERGY METABOLISM, AND CELLULAR RESPONSES TO STRESS AND INJURY. IMPORTANTLY, THESE EXPRESSION CHANGES WERE IMPACTFUL, APPARENT FROM ADRENAL HYPERTROPHY AND AUGMENTED BEHAVIORAL RESPONSES TO STRESS IN ADULTHOOD. CONCLUSIONS: WE UNCOVER A NOVEL REPERTOIRE OF STRESS-REGULATING CRF CELL TYPES DIFFERENTIALLY AFFECTED BY ELA AND RESULTING IN AUGMENTED STRESS VULNERABILITY, WITH RELEVANCE TO THE ORIGINS OF STRESS-RELATED AFFECTIVE DISORDERS. 2023 15 4627 30 NEUROENDOCRINOLOGICAL AND EPIGENETIC MECHANISMS SUBSERVING AUTONOMIC IMBALANCE AND HPA DYSFUNCTION IN THE METABOLIC SYNDROME. IMPACT OF ENVIRONMENTAL STRESS UPON PATHOPHYSIOLOGY OF THE METABOLIC SYNDROME (METS) HAS BEEN SUBSTANTIATED BY EPIDEMIOLOGICAL, PSYCHOPHYSIOLOGICAL, AND ENDOCRINOLOGICAL STUDIES. THIS REVIEW DISCUSSES RECENT ADVANCES IN THE UNDERSTANDING OF CAUSATIVE ROLES OF NUTRITIONAL FACTORS, SYMPATHOMEDULLO-ADRENAL (SMA) AND HYPOTHALAMIC-PITUITARY ADRENOCORTICAL (HPA) AXES, AND ADIPOSE TISSUE CHRONIC LOW-GRADE INFLAMMATION PROCESSES IN METS. DISTURBANCES IN THE NEUROENDOCRINE SYSTEMS FOR LEPTIN, MELANOCORTIN, AND NEUROPEPTIDE Y (NPY)/AGOUTI-RELATED PROTEIN SYSTEMS HAVE BEEN FOUND RESULTING DIRECTLY IN METS-LIKE CONDITIONS. THE REVIEW IDENTIFIES CANDIDATE RISK GENES FROM FACTORS SHOWN CRITICAL FOR THE FUNCTIONING OF EACH OF THESE NEUROENDOCRINE SIGNALING CASCADES. IN ITS META-ANALYTIC PART, RECENT STUDIES IN EPIGENETIC MODIFICATION (HISTONE METHYLATION, ACETYLATION, PHOSPHORYLATION, UBIQUITINATION) AND POSTTRANSCRIPTIONAL GENE REGULATION BY MICRORNAS ARE EVALUATED. SEVERAL STUDIES SUGGEST MODIFICATION MECHANISMS OF EARLY LIFE STRESS (ELS) AND DIET-INDUCED OBESITY (DIO) PROGRAMMING IN THE HYPOTHALAMIC REGIONS WITH POPULATIONS OF POMC-EXPRESSING NEURONS. EPIGENETIC MODIFICATIONS WERE FOUND IN CORTISOL (HERE HSD11B1 EXPRESSION), MELANOCORTIN, LEPTIN, NPY, AND ADIPONECTIN GENES. WITH RESPECT TO ADIPOSITY GENES, EPIGENETIC MODIFICATIONS WERE DOCUMENTED FOR FAT MASS GENE CLUSTER APOA1/C3/A4/A5, AND THE LIPOLYSIS GENE LIPE. WITH REGARD TO INFLAMMATORY, IMMUNE AND SUBCELLULAR METABOLISM, PPARG, NKBF1, TNFA, TCF7C2, AND THOSE GENES EXPRESSING CYTOCHROME P450 FAMILY ENZYMES INVOLVED IN STEROIDOGENESIS AND IN HEPATIC LIPOPROTEINS WERE DOCUMENTED FOR EPIGENETIC MODIFICATIONS. 2016 16 2000 30 EPIGENETIC AND NON-CODING REGULATION OF ALCOHOL ABUSE AND ADDICTION. ALCOHOL USE DISORDER IS A CHRONIC DEBILITATED CONDITION ADVERSELY AFFECTING THE LIVES OF MILLIONS OF INDIVIDUALS THROUGHOUT THE MODERN WORLD. INDIVIDUALS SUFFERING FROM AN ALCOHOL USE DISORDER DIAGNOSIS FREQUENTLY HAVE SERIOUS COOCCURRING CONDITIONS, WHICH OFTEN FURTHER EXACERBATES PROBLEMATIC DRINKING BEHAVIOR. COMPREHENDING THE BIOCHEMICAL PROCESSES UNDERLYING THE PROGRESSION AND PERPETUATION OF DISEASE IS ESSENTIAL FOR MITIGATING MALADAPTIVE BEHAVIOR IN ORDER TO RESTORE BOTH PHYSIOLOGICAL AND PSYCHOLOGICAL HEALTH. THE RANGE OF CELLULAR AND BIOLOGICAL SYSTEMS CONTRIBUTING TO, AND AFFECTED BY, ALCOHOL USE DISORDER AND OTHER COMORBID DISORDERS NECESSITATES A FUNDAMENTAL GRASP OF INTRICATE FUNCTIONAL RELATIONSHIPS THAT GOVERN MOLECULAR BIOLOGY. EPIGENETIC FACTORS ARE RECOGNIZED AS ESSENTIAL MEDIATORS OF CELLULAR BEHAVIOR, ORCHESTRATING A SYMPHONY OF GENE EXPRESSION CHANGES WITHIN MULTICELLULAR ENVIRONMENTS THAT ARE ULTIMATELY RESPONSIBLE FOR DIRECTING HUMAN BEHAVIOR. UNDERSTANDING THE EPIGENETIC AND TRANSCRIPTIONAL REGULATORY MECHANISMS INVOLVED IN THE PATHOGENESIS OF DISEASE IS IMPORTANT FOR IMPROVING AVAILABLE PHARMACOTHERAPIES AND REDUCING THE INCIDENCE OF ALCOHOL ABUSE AND COOCCURRING CONDITIONS. 2021 17 2913 31 GENE REGULATORY MECHANISMS UNDERLYING SEX DIFFERENCES IN BRAIN DEVELOPMENT AND PSYCHIATRIC DISEASE. THE SEXUAL DIFFERENTIATION OF THE MAMMALIAN NERVOUS SYSTEM REQUIRES THE PRECISE COORDINATION OF THE TEMPORAL AND SPATIAL REGULATION OF GENE EXPRESSION IN DIVERSE CELL TYPES. SEX HORMONES ACT AT MULTIPLE DEVELOPMENTAL TIME POINTS TO SPECIFY SEX-TYPICAL DIFFERENTIATION DURING EMBRYONIC AND EARLY DEVELOPMENT AND TO COORDINATE SUBSEQUENT RESPONSES TO GONADAL HORMONES LATER IN LIFE BY ESTABLISHING SEX-TYPICAL PATTERNS OF EPIGENETIC MODIFICATIONS ACROSS THE GENOME. THUS, MUTATIONS ASSOCIATED WITH NEUROPSYCHIATRIC CONDITIONS MAY RESULT IN SEXUALLY DIMORPHIC SYMPTOMS BY ACTING ON DIFFERENT NEURAL SUBSTRATES OR CHROMATIN LANDSCAPES IN MALES AND FEMALES. FINALLY, AS STRESS HORMONE SIGNALING MAY DIRECTLY ALTER THE MOLECULAR MACHINERY THAT INTERACTS WITH SEX HORMONE RECEPTORS TO REGULATE GENE EXPRESSION, THE CONTRIBUTION OF CHRONIC STRESS TO THE PATHOGENESIS OR PRESENTATION OF MENTAL ILLNESS MAY BE ADDITIONALLY DIFFERENT BETWEEN THE SEXES. HERE, WE REVIEW THE MECHANISMS THAT CONTRIBUTE TO SEXUAL DIFFERENTIATION IN THE MAMMALIAN NERVOUS SYSTEM AND CONSIDER SOME OF THE IMPLICATIONS OF THESE PROCESSES FOR SEX DIFFERENCES IN NEUROPSYCHIATRIC CONDITIONS. 2018 18 6755 40 WILL WIDESPREAD SYNTHETIC OPIOID CONSUMPTION INDUCE EPIGENETIC CONSEQUENCES IN FUTURE GENERATIONS? A GROWING NUMBER OF EVIDENCE DEMONSTRATES THAT ANCESTRAL EXPOSURE TO XENOBIOTICS (POLLUTANTS, DRUGS OF ABUSE, ETC.) CAN PERTURB THE PHYSIOLOGY AND BEHAVIOR OF DESCENDANTS. BOTH MATERNAL AND PATERNAL TRANSMISSION OF PHENOTYPE ACROSS GENERATIONS HAS BEEN PROVED, DEMONSTRATING THAT PARENTAL DRUG HISTORY MAY HAVE SIGNIFICANT IMPLICATIONS FOR SUBSEQUENT GENERATIONS. IN THE LAST YEARS, THE BURDEN OF NOVEL SYNTHETIC OPIOID (NSO) CONSUMPTION, DUE TO INCREASED MEDICAL PRESCRIPTION OF PAIN MEDICATIONS AND TO EASIER ACCESSIBILITY OF THESE SUBSTANCES ON ILLEGAL MARKET, IS RAISING NEW QUESTIONS FIRST IN TERM OF PUBLIC HEALTH, BUT ALSO ABOUT THE CONSEQUENCES OF THE PARENTAL USE OF THESE DRUGS ON FUTURE GENERATIONS. BESIDES BEING ASSOCIATED TO THE NEONATAL ABSTINENCE SYNDROME, IN UTERO EXPOSURE TO OPIOIDS HAS AN IMPACT ON NEURONAL DEVELOPMENT WITH LONG-TERM REPERCUSSIONS THAT ARE POTENTIALLY TRANSMITTED TO SUBSEQUENT GENERATIONS. IN ADDITION, RECENT REPORTS SUGGEST THAT OPIOID USE EVEN BEFORE CONCEPTION INFLUENCES THE REACTIVITY TO OPIOIDS OF THE PROGENY AND THE FOLLOWING GENERATIONS, LIKELY THROUGH EPIGENETIC MECHANISMS. THIS REVIEW DESCRIBES THE CURRENT KNOWLEDGE ABOUT THE TRANSGENERATIONAL EFFECTS OF OPIOID CONSUMPTION. WE SUMMARIZE THE PRECLINICAL AND CLINICAL FINDINGS SHOWING THE IMPLICATIONS FOR THE SUBSEQUENT GENERATIONS OF PARENTAL EXPOSURE TO OPIOIDS EARLIER IN LIFE. LIMITATIONS OF THE EXISTING DATA ON NSOS AND NEW PERSPECTIVES OF THE RESEARCH ARE ALSO DISCUSSED, AS WELL AS CLINICAL AND FORENSIC CONSEQUENCES. 2018 19 5091 32 PLACENTAL DISEASES ASSOCIATED WITH ASSISTED REPRODUCTIVE TECHNOLOGY. THE PLACENTA DEVELOPS FROM THE OUTER TROPHOBLASTIC LAYER FOLLOWING THE DIFFERENTIATION OF THE FERTILIZED OVUM AND IS THEREFORE MORE SUSCEPTIBLE TO EPIGENETIC REGULATORY CHANGES CAUSED BY ENVIRONMENTAL INTERVENTIONS AND INFLUENCES DURING ASSISTED REPRODUCTIVE TECHNOLOGY. FURTHERMORE, THE PLACENTA REGULATES THE DEVELOPMENT OF THE FETAL HEART, BRAIN, KIDNEYS, BONES, AND OTHER TISSUES AND ORGANS [1]. PLACENTAL DYSPLASIA LEADS TO POOR PERINATAL OUTCOMES AS WELL AS LONG-TERM HEALTH RISKS LATER IN LIFE, INCLUDING NEURODEVELOPMENTAL DISORDERS, TUMORS, AND ADULT METABOLIC SYNDROME [2,3]. IN VIEW OF THE DECISIVE ROLE OF THE PLACENTA DURING INTRAUTERINE FETAL DEVELOPMENT, GRAHAM J. BURTON, AN EXPERT IN PLACENTOLOGY FROM THE UNIVERSITY OF CAMBRIDGE, FORMALLY PROPOSED THE THEORY OF "PLACENTA-DERIVED CHRONIC DISEASES" IN 2018 BASED ON EMBRYONIC-DERIVED DISEASES [4]. IN THIS REVIEW, WE SUMMARIZED THE CHANGES IN PLACENTAL MORPHOLOGY AND STRUCTURE, GROWTH DYNAMICS, IMPRINTED AND NON-IMPRINTED GENES, AND OTHER ASPECTS ATTRIBUTABLE TO ASSISTED REPRODUCTION TECHNOLOGY. OUR REVIEW PROVIDES A THEORETICAL BASIS FOR FURTHER RESEARCH ON PLACENTAL CHANGES CAUSED BY ASSISTED REPRODUCTIVE TECHNOLOGY THAT ARE MOST STRONGLY ASSOCIATED WITH AN INCREASED RISK OF NEONATAL LONG-TERM DISEASES. 2021 20 1766 37 EARLY-LIFE EXPERIENCES AND THE DEVELOPMENT OF ADULT DISEASES WITH A FOCUS ON MENTAL ILLNESS: THE HUMAN BIRTH THEORY. IN MAMMALS, EARLY ADVERSE EXPERIENCES, INCLUDING MOTHER-PUP INTERACTIONS, SHAPE THE RESPONSE OF AN INDIVIDUAL TO CHRONIC STRESS OR TO STRESS-RELATED DISEASES DURING ADULT LIFE. THIS HAS LED TO THE ELABORATION OF THE THEORY OF THE DEVELOPMENTAL ORIGINS OF HEALTH AND DISEASE, IN PARTICULAR ADULT DISEASES SUCH AS CARDIOVASCULAR AND METABOLIC DISORDERS. IN ADDITION, IN HUMANS, AS STATED BY MASSIMO FAGIOLI'S HUMAN BIRTH THEORY, BIRTH IS HEALTHY AND EQUAL FOR ALL INDIVIDUALS, SO THAT MENTAL ILLNESS DEVELOP EXCLUSIVELY IN THE POSTNATAL PERIOD BECAUSE OF THE QUALITY OF THE RELATIONSHIP IN THE FIRST YEAR OF LIFE. THUS, THIS REVIEW FOCUSES ON THE IMPORTANCE OF PROGRAMMING DURING THE EARLY DEVELOPMENTAL PERIOD ON THE MANIFESTATION OF ADULT DISEASES IN BOTH ANIMAL MODELS AND HUMANS. CONSIDERING THE OBVIOUS DIFFERENCES BETWEEN ANIMALS AND HUMANS WE CANNOT SYSTEMATICALLY MOVE FROM ANIMAL MODELS TO HUMANS. CONSEQUENTLY, IN THE FIRST PART OF THIS REVIEW, WE WILL DISCUSS HOW ANIMAL MODELS CAN BE USED TO DISSECT THE INFLUENCE OF ADVERSE EVENTS OCCURRING DURING THE PRENATAL AND POSTNATAL PERIODS ON THE DEVELOPMENTAL TRAJECTORIES OF THE OFFSPRING, AND IN THE SECOND PART, WE WILL DISCUSS THE ROLE OF POSTNATAL CRITICAL PERIODS ON THE DEVELOPMENT OF MENTAL DISEASES IN HUMANS. EPIGENETIC MECHANISMS THAT CAUSE REVERSIBLE MODIFICATIONS IN GENE EXPRESSION, DRIVING THE DEVELOPMENT OF A PATHOLOGICAL PHENOTYPE IN RESPONSE TO A NEGATIVE EARLY POSTNATAL ENVIRONMENT, MAY LIE AT THE CORE OF THIS PROGRAMMING, THEREBY PROVIDING POTENTIAL NEW THERAPEUTIC TARGETS. THE CONCEPT OF THE HUMAN BIRTH THEORY LEADS TO A COMPREHENSION OF THE MENTAL ILLNESS AS A PATHOLOGY OF THE HUMAN RELATIONSHIP IMMEDIATELY AFTER BIRTH AND DURING THE FIRST YEAR OF LIFE. 2017