1 236 126 ADENOMYOSIS: MECHANISMS AND PATHOGENESIS. ADENOMYOSIS IS A COMMON DISORDER OF THE UTERUS, AND IS ASSOCIATED WITH AN ENLARGED UTERUS, HEAVY MENSTRUAL BLEEDING (HMB), PELVIC PAIN, AND INFERTILITY. IT IS CHARACTERIZED BY ENDOMETRIAL EPITHELIAL CELLS AND STROMAL FIBROBLASTS ABNORMALLY FOUND IN THE MYOMETRIUM WHERE THEY ELICIT HYPERPLASIA AND HYPERTROPHY OF SURROUNDING SMOOTH MUSCLE CELLS. WHILE BOTH THE MECHANISTIC PROCESSES AND THE PATHOGENESIS OF ADENOMYOSIS ARE UNCERTAIN, SEVERAL THEORIES HAVE BEEN PUT FORWARD ADDRESSING HOW THIS DISEASE DEVELOPS. THESE INCLUDE INTRINSIC OR INDUCED (1) MICROTRAUMA OF THE ENDOMETRIAL-MYOMETRIAL INTERFACE; (2) ENHANCED INVASION OF ENDOMETRIUM INTO MYOMETRIUM; (3) METAPLASIA OF STEM CELLS IN MYOMETRIUM; (4) INFILTRATION OF ENDOMETRIAL CELLS IN RETROGRADE MENSTRUAL EFFLUENT INTO THE UTERINE WALL FROM THE SEROSAL SIDE; (5) INDUCTION OF ADENOMYOTIC LESIONS BY ABERRANT LOCAL STEROID AND PITUITARY HORMONES; AND (6) ABNORMAL UTERINE DEVELOPMENT IN RESPONSE TO GENETIC AND EPIGENETIC MODIFICATIONS. DYSMENORRHEA, HMB, AND INFERTILITY ARE LIKELY RESULTS OF INFLAMMATION, NEUROGENESIS, ANGIOGENESIS, AND CONTRACTILE ABNORMALITIES IN THE ENDOMETRIAL AND MYOMETRIAL COMPONENTS. ELUCIDATING MECHANISMS UNDERLYING THE PATHOGENESIS OF ADENOMYOSIS RAISE POSSIBILITIES TO DEVELOP TARGETED THERAPIES TO AMELIORATE SYMPTOMS BEYOND THE CURRENT AGENTS THAT ARE LARGELY INEFFECTIVE. HEREIN, WE ADDRESS THESE POSSIBLE ETIOLOGIES AND DATA THAT SUPPORT UNDERLYING MECHANISMS. 2020 2 5242 36 PROGESTERONE RESISTANCE IN ENDOMETRIOSIS: ORIGINS, CONSEQUENCES AND INTERVENTIONS. ENDOMETRIOSIS IS A COMMON CAUSE OF PELVIC PAIN AND AFFECTS UP TO 10% OF WOMEN OF REPRODUCTIVE AGE. ABERRANT PROGESTERONE SIGNALING IN THE ENDOMETRIUM PLAYS A SIGNIFICANT ROLE IN IMPAIRED DECIDUALIZATION AND ESTABLISHMENT OF ECTOPIC ENDOMETRIAL IMPLANTS. EUTOPIC ENDOMETRIAL CELLS FROM WOMEN WITH ENDOMETRIOSIS FAIL TO DOWNREGULATE GENES NEEDED FOR DECIDUALIZATION, SUCH AS THOSE INVOLVED IN CELL CYCLE REGULATION, LEADING TO UNBRIDLED PROLIFERATION. SEVERAL CAUSES OF PROGESTERONE RESISTANCE IN THE ENDOMETRIUM HAVE BEEN POSTULATED, INCLUDING CONGENITAL "PRECONDITIONING", WHEREBY THE IN UTERO ENVIRONMENT RENDERS INFANTS SUSCEPTIBLE TO NEONATAL UTERINE BLEEDING AND ENDOMETRIOSIS. PROGESTERONE ACTION IS CRUCIAL TO DECREASING INFLAMMATION IN THE ENDOMETRIUM, AND DEVIANT PROGESTERONE SIGNALING RESULTS IN A PROINFLAMMATORY PHENOTYPE. CONVERSELY, CHRONIC INFLAMMATION CAN INDUCE A PROGESTERONE-RESISTANT STATE. REPETITIVE RETROGRADE ENDOMETRIAL SHEDDING BEGETS CHRONIC PERITONEAL INFLAMMATION, WHICH FURTHER EXACERBATES PROGESTERONE RESISTANCE. GENETIC CAUSES OF PROGESTERONE RESISTANCE INCLUDE PROGESTERONE RECEPTOR GENE POLYMORPHISMS, ALTERED MICRORNA EXPRESSION, AND EPIGENETIC MODIFICATIONS TO PROGESTERONE RECEPTORS AND THEIR TARGETS. ENVIRONMENTAL TOXINS SUCH AS DIOXIN PLAY A POSSIBLE ROLE IN THE GENESIS OF ENDOMETRIOSIS BY PERMITTING AN INFLAMMATORY MILIEU. A CONSEQUENCE OF IMPAIRED PROGESTERONE ACTION IS THAT HORMONAL THERAPY IS RENDERED INEFFECTIVE FOR A SUBSET OF WOMEN WITH ENDOMETRIOSIS. SYNTHETIC PROGESTINS, SUCH AS DIENOGEST, MAY OVERCOME THIS PHENOMENON BY INCREASING PROGESTERONE RECEPTOR EXPRESSION AND DECREASING PROINFLAMMATORY CYTOKINES. OTHER MODALITIES INCLUDE HIGH DOSE DEPOT FORMULATIONS OF PROGESTINS, MEDICATED INTRAUTERINE DEVICES AND THE LIKELY ADVENT OF ORAL GNRH ANTAGONISTS. UNEARTHING ROOT CAUSES OF PROGESTERONE INACTION IN ENDOMETRIOSIS WILL AID IN THE DEVELOPMENT OF NOVEL THERAPEUTICS GEARED TOWARD PREVENTION AND TREATMENT. 2017 3 2669 39 ESTROGEN- AND PROGESTERONE (P4)-MEDIATED EPIGENETIC MODIFICATIONS OF ENDOMETRIAL STROMAL CELLS (ENSCS) AND/OR MESENCHYMAL STEM/STROMAL CELLS (MSCS) IN THE ETIOPATHOGENESIS OF ENDOMETRIOSIS. ENDOMETRIOSIS IS A COMMON CHRONIC INFLAMMATORY CONDITION IN WHICH ENDOMETRIAL TISSUE APPEARS OUTSIDE THE UTERINE CAVITY. BECAUSE ECTOPIC ENDOMETRIOSIS CELLS EXPRESS BOTH ESTROGEN AND PROGESTERONE (P4) RECEPTORS, THEY GROW AND UNDERGO CYCLIC PROLIFERATION AND BREAKDOWN SIMILAR TO THE ENDOMETRIUM. THIS DEBILITATING GYNECOLOGICAL DISEASE AFFECTS UP TO 15% OF REPRODUCTIVE AGED WOMEN. DESPITE MANY YEARS OF RESEARCH, THE ETIOPATHOGENESIS OF ENDOMETRIAL LESIONS REMAINS UNCLEAR. RETROGRADE TRANSPORT OF THE VIABLE MENSTRUAL ENDOMETRIAL CELLS WITH RETAINED ABILITY FOR ATTACHMENT WITHIN THE PELVIC CAVITY, PROLIFERATION, DIFFERENTIATION AND SUBSEQUENT INVASION INTO THE SURROUNDING TISSUE CONSTITUTES THE RATIONALE FOR WIDELY ACCEPTED IMPLANTATION THEORY. ACCORDINGLY, THE MOST ABUNDANT CELLS IN THE ENDOMETRIUM ARE ENDOMETRIAL STROMAL CELLS (ENSCS). THESE CELLS CONSTITUTE A PARTICULAR POPULATION WITH CLONOGENIC ACTIVITY THAT RESEMBLES PROPERTIES OF MESENCHYMAL STEM/STROMAL CELLS (MSCS). THUS, A SIGNIFICANT ROLE OF STEM CELL-BASED DYSFUNCTION IN FORMATION OF THE INITIAL ENDOMETRIAL LESIONS IS SUSPECTED. THERE IS INCREASING EVIDENCE THAT THE ROLE OF EPIGENETIC MECHANISMS AND PROCESSES IN ENDOMETRIOSIS HAVE BEEN UNDERESTIMATED. THE IMPORTANCE OF EXCESS ESTROGEN EXPOSURE AND P4 RESISTANCE IN EPIGENETIC HOMEOSTASIS FAILURE IN THE ENDOMETRIAL/ENDOMETRIOTIC TISSUE ARE CRUCIAL. EPIGENETIC ALTERATIONS REGARDING TRANSCRIPTION FACTORS OF ESTROGEN AND P4 SIGNALING PATHWAYS IN MSCS ARE ROBUST IN ENDOMETRIOTIC TISSUE. THUS, PERSPECTIVES FOR THE FUTURE MAY INCLUDE MSCS AND ENSCS AS THE TARGETS OF EPIGENETIC THERAPIES IN THE PREVENTION AND TREATMENT OF ENDOMETRIOSIS. HERE, WE REVIEWED THE CURRENT KNOWN CHANGES IN THE EPIGENETIC BACKGROUND OF ENSCS AND MSCS DUE TO ESTROGEN/P4 IMBALANCES IN THE CONTEXT OF ETIOPATHOGENESIS OF ENDOMETRIOSIS. GRAPHICAL ABSTRACT. 2021 4 1891 36 ENDOMETRIOSIS. PELVIC ENDOMETRIOSIS IS A COMPLEX SYNDROME CHARACTERIZED BY AN ESTROGEN-DEPENDENT CHRONIC INFLAMMATORY PROCESS THAT AFFECTS PRIMARILY PELVIC TISSUES, INCLUDING THE OVARIES. IT IS CAUSED WHEN SHED ENDOMETRIAL TISSUE TRAVELS RETROGRADE INTO THE LOWER ABDOMINAL CAVITY. ENDOMETRIOSIS IS THE MOST COMMON CAUSE OF CHRONIC PELVIC PAIN IN WOMEN AND IS ASSOCIATED WITH INFERTILITY. THE UNDERLYING PATHOLOGIC MECHANISMS IN THE INTRACAVITARY ENDOMETRIUM AND EXTRAUTERINE ENDOMETRIOTIC TISSUE INVOLVE DEFECTIVELY PROGRAMMED ENDOMETRIAL MESENCHYMAL PROGENITOR/STEM CELLS. ALTHOUGH ENDOMETRIOTIC STROMAL CELLS, WHICH COMPOSE THE BULK OF ENDOMETRIOTIC LESIONS, DO NOT CARRY SOMATIC MUTATIONS, THEY DEMONSTRATE SPECIFIC EPIGENETIC ABNORMALITIES THAT ALTER EXPRESSION OF KEY TRANSCRIPTION FACTORS. FOR EXAMPLE, GATA-BINDING FACTOR-6 OVEREXPRESSION TRANSFORMS AN ENDOMETRIAL STROMAL CELL TO AN ENDOMETRIOTIC PHENOTYPE, AND STEROIDOGENIC FACTOR-1 OVEREXPRESSION CAUSES EXCESSIVE PRODUCTION OF ESTROGEN, WHICH DRIVES INFLAMMATION VIA PATHOLOGICALLY HIGH LEVELS OF ESTROGEN RECEPTOR-BETA. PROGESTERONE RECEPTOR DEFICIENCY CAUSES PROGESTERONE RESISTANCE. POPULATIONS OF ENDOMETRIAL AND ENDOMETRIOTIC EPITHELIAL CELLS ALSO HARBOR MULTIPLE CANCER DRIVER MUTATIONS, SUCH AS KRAS, WHICH MAY BE ASSOCIATED WITH THE ESTABLISHMENT OF PELVIC ENDOMETRIOSIS OR OVARIAN CANCER. IT IS NOT KNOWN HOW INTERACTIONS BETWEEN EPIGENOMICALLY DEFECTIVE STROMAL CELLS AND THE MUTATED GENES IN EPITHELIAL CELLS CONTRIBUTE TO THE PATHOGENESIS OF ENDOMETRIOSIS. ENDOMETRIOSIS-ASSOCIATED PELVIC PAIN IS MANAGED BY SUPPRESSION OF OVULATORY MENSES AND ESTROGEN PRODUCTION, CYCLOOXYGENASE INHIBITORS, AND SURGICAL REMOVAL OF PELVIC LESIONS, AND IN VITRO FERTILIZATION IS FREQUENTLY USED TO OVERCOME INFERTILITY. ALTHOUGH NOVEL TARGETED TREATMENTS ARE BECOMING AVAILABLE, AS ENDOMETRIOSIS PATHOPHYSIOLOGY IS BETTER UNDERSTOOD, PREVENTIVE APPROACHES SUCH AS LONG-TERM OVULATION SUPPRESSION MAY PLAY A CRITICAL ROLE IN THE FUTURE. 2019 5 6237 31 THE MAIN THEORIES ON THE PATHOGENESIS OF ENDOMETRIOSIS. ENDOMETRIOSIS IS A COMPLEX DISEASE, WHICH IS DEFINED BY ABNORMAL GROWTH OF ENDOMETRIAL TISSUE OUTSIDE THE UTERUS. IT AFFECTS ABOUT 10% OF WOMEN OF REPRODUCTIVE AGE ALL OVER THE WORLD. ENDOMETRIOSIS CAUSES SYMPTOMS THAT NOTABLY WORSEN PATIENT'S WELL-BEING-SUCH AS SEVERE PELVIC PAIN, DYSFUNCTION OF THE ORGANS OF PELVIC CAVITY, INFERTILITY AND SECONDARY MENTAL ISSUES. THE DIAGNOSIS OF ENDOMETRIOSIS IS QUITE OFTEN DELAYED BECAUSE OF NONSPECIFIC MANIFESTATIONS. SINCE THE DISEASE WAS DEFINED, SEVERAL DIFFERENT PATHOGENETIC PATHWAYS HAVE BEEN CONSIDERED, INCLUDING RETROGRADE MENSTRUATION, BENIGN METASTASIS, IMMUNE DYSREGULATION, COELOMIC METAPLASIA, HORMONAL DISBALANCE, INVOLVEMENT OF STEM CELLS AND ALTERATIONS IN EPIGENETIC REGULATION, BUT THE TRUE PATHOGENESIS OF ENDOMETRIOSIS REMAINS POORLY UNDERSTOOD. THE KNOWLEDGE OF THE EXACT MECHANISM OF THE ORIGIN AND PROGRESSION OF THIS DISEASE IS SIGNIFICANT FOR THE APPROPRIATE TREATMENT. THEREFORE, THIS REVIEW REPORTS THE MAIN PATHOGENETIC THEORIES OF ENDOMETRIOSIS BASED ON CURRENT STUDIES. 2023 6 4956 28 PATHOGENESIS OF ENDOMETRIOSIS: FOCUS ON ADENOGENESIS-RELATED FACTORS. ENDOMETRIOSIS CAN BE DEFINED AS THE PRESENCE OF THE ENDOMETRIUM OUTSIDE THE UTERINE CAVITY. IT AFFECTS APPROXIMATELY 10% OF WOMEN OF REPRODUCTIVE AGE AND CAUSES INFERTILITY, CHRONIC PAIN, AND DETERIORATION OF THE QUALITY OF LIFE. SINCE THE IDENTIFICATION OF THE DISEASE, VARIOUS PATHOGENETIC MECHANISMS HAVE BEEN PROPOSED, SUCH AS RETROGRADE MENSTRUATION, COELOMIC METAPLASIA, HORMONAL IMBALANCE, STEM CELL INVOLVEMENT, AND ALTERATIONS IN EPIGENETIC REGULATION. HOWEVER, THE UNDERLYING PATHOGENESIS OF ENDOMETRIOSIS REMAINS INADEQUATELY UNDERSTOOD. ELUCIDATION OF THE PRECISE MECHANISM OF THE DEVELOPMENT AND PROGRESSION OF ENDOMETRIOSIS IS CRUCIAL FOR EFFECTIVE TREATMENT. THIS REVIEW PRESENTS THE MAJOR PATHOGENETIC THEORIES OF ENDOMETRIOSIS BASED ON CURRENT RESEARCH STUDIES WITH A MAJOR FOCUS ON THE POTENTIAL ROLE OF UTERINE FACTORS. 2023 7 1892 23 ENDOMETRIOSIS: EPIDEMIOLOGY, CLASSIFICATION, PATHOGENESIS, TREATMENT AND GENETICS (REVIEW OF LITERATURE). ENDOMETRIOSIS IS A "MYSTERIOUS" DISEASE AND ITS EXACT CAUSE HAS NOT YET BEEN ESTABLISHED. AMONG THE ETIOLOGICAL FACTORS, CONGENITAL, ENVIRONMENTAL, EPIGENETIC, AUTOIMMUNE AND ALLERGIC FACTORS ARE LISTED. IT IS BELIEVED THAT THE PRIMARY MECHANISM OF THE FORMATION OF ENDOMETRIOSIS FOCI IS RETROGRADE MENSTRUATION, I.E., THE PASSAGE OF MENSTRUAL BLOOD THROUGH THE FALLOPIAN TUBES INTO THE PERITONEAL CAVITY AND IMPLANTATION OF EXFOLIATED ENDOMETRIAL CELLS. HOWEVER, SINCE THIS MECHANISM IS ALSO OBSERVED IN HEALTHY WOMEN, OTHER FACTORS MUST ALSO BE INVOLVED IN THE FORMATION OF ENDOMETRIOSIS FOCI. ENDOMETRIOSIS IS IN MANY WOMEN THE CAUSE OF INFERTILITY, CHRONIC PAIN AND THE DETERIORATION OF THE QUALITY OF LIFE. IT ALSO REPRESENTS A SIGNIFICANT FINANCIAL BURDEN ON HEALTH SYSTEMS. THE ARTICLE PRESENTS A REVIEW OF THE LITERATURE ON ENDOMETRIOSIS-A DISEASE AFFECTING WOMEN THROUGHOUT THE WORLD. 2021 8 4310 32 MICRORNAS AND PROGESTERONE RECEPTOR SIGNALING IN ENDOMETRIOSIS PATHOPHYSIOLOGY. ENDOMETRIOSIS IS A SIGNIFICANT DISEASE CHARACTERIZED BY INFERTILITY AND PELVIC PAIN IN WHICH ENDOMETRIAL STROMAL AND GLANDULAR TISSUE GROW IN ECTOPIC LOCATIONS. ALTERED RESPONSIVENESS TO PROGESTERONE IS A CONTRIBUTING FACTOR TO ENDOMETRIOSIS PATHOPHYSIOLOGY, BUT THE PRECISE MECHANISMS ARE POORLY UNDERSTOOD. PROGESTERONE RESISTANCE INFLUENCES BOTH THE EUTOPIC AND ECTOPIC (ENDOMETRIOTIC LESION) ENDOMETRIUM. AN INABILITY OF THE EUTOPIC ENDOMETRIUM TO PROPERLY RESPOND TO PROGESTERONE IS BELIEVED TO CONTRIBUTE TO THE INFERTILITY ASSOCIATED WITH THE DISEASE, WHILE AN ALTERED RESPONSIVENESS OF ENDOMETRIOTIC LESION TISSUE MAY CONTRIBUTE TO THE SURVIVAL OF THE ECTOPIC TISSUE AND ASSOCIATED SYMPTOMS. WOMEN WITH ENDOMETRIOSIS EXPRESS ALTERED LEVELS OF SEVERAL ENDOMETRIAL PROGESTERONE TARGET GENES WHICH MAY BE DUE TO THE ABNORMAL EXPRESSION AND/OR FUNCTION OF PROGESTERONE RECEPTORS AND/OR CHAPERONE PROTEINS, AS WELL AS INFLAMMATION, GENETICS, AND EPIGENETICS. MIRNAS ARE A CLASS OF EPIGENETIC MODULATORS PROPOSED TO PLAY A ROLE IN ENDOMETRIOSIS PATHOPHYSIOLOGY, INCLUDING THE MODULATION OF PROGESTERONE SIGNALING. IN THIS PAPER, WE SUMMARIZE THE ROLE OF PROGESTERONE RECEPTORS AND PROGESTERONE SIGNALING IN ENDOMETRIOSIS PATHOPHYSIOLOGY, REVIEW MIRNAS, WHICH ARE OVER-EXPRESSED IN ENDOMETRIOSIS TISSUES AND FLUIDS, AND FOLLOW THIS WITH A DISCUSSION ON THE POTENTIAL REGULATION OF KEY PROGESTERONE SIGNALING COMPONENTS BY THESE MIRNAS, CONCLUDING WITH SUGGESTIONS FOR FUTURE RESEARCH ENDEAVORS IN THIS AREA. 2022 9 4950 31 PATHOGENESIS OF ADENOMYOSIS: AN UPDATE ON MOLECULAR MECHANISMS. ADENOMYOSIS IS A UTERINE DISORDER BECOMING MORE COMMONLY DIAGNOSED IN WOMEN OF REPRODUCTIVE AGE BECAUSE OF DIAGNOSTIC IMAGING ADVANCEMENTS. THE NEW EPIDEMIOLOGICAL SCENARIO AND THE CLINICAL EVIDENCE OF PELVIC PAIN, ABNORMAL UTERINE BLEEDING AND INFERTILITY ARE CHANGING THE CLASSIC PERSPECTIVE OF ADENOMYOSIS AS A PREMENOPAUSAL DISEASE. IN THE LAST DECADE, THE EVALUATION OF MULTIPLE MOLECULAR MEDIATORS HAS IMPROVED OUR KNOWLEDGE OF PATHOGENIC MECHANISMS OF ADENOMYOSIS, SUPPORTING THAT THIS IS AN INDEPENDENT DISEASE FROM ENDOMETRIOSIS. ALTHOUGH THEY SHARE COMMON GENETIC MUTATIONS AND EPIGENETIC CHANGES IN SEX STEROID HORMONE RECEPTORS AND SIMILAR INFLAMMATORY MEDIATORS, AN INCREASING NUMBER OF RECENT STUDIES HAVE SHOWN PATHOGENIC PATHWAYS SPECIFIC FOR ADENOMYOSIS. A PUBMED SEARCH UP TO OCTOBER 2016 SUMMARIZES THE KEY MEDIATORS OF PAIN, ABNORMAL UTERINE BLEEDING AND INFERTILITY IN ADENOMYOSIS, INCLUDING SEX STEROID HORMONE RECEPTORS, INFLAMMATORY MOLECULES, EXTRACELLULAR MATRIX ENZYMES, GROWTH FACTORS AND NEUROANGIOGENIC FACTORS. 2017 10 4688 25 NEW UNDERSTANDING OF DIAGNOSIS, TREATMENT AND PREVENTION OF ENDOMETRIOSIS. FOR 100 YEARS, PELVIC ENDOMETRIOSIS HAS BEEN CONSIDERED TO ORIGINATE FROM THE IMPLANTATION OF ENDOMETRIAL CELLS FOLLOWING RETROGRADE MENSTRUATION OR METAPLASIA. SINCE SOME OBSERVATIONS, SUCH AS THE CLONAL ASPECT, THE BIOCHEMICAL VARIABILITY OF LESIONS AND ENDOMETRIOSIS IN WOMEN WITHOUT ENDOMETRIUM, THE GENETIC-EPIGENETIC (G-E) THEORY DESCRIBES THAT ENDOMETRIOSIS ONLY BEGINS AFTER A SERIES OF CUMULATIVE G-E CELLULAR CHANGES. THIS EXPLAINS THAT THE ENDOMETRIOTIC MAY ORIGINATE FROM ANY PLURIPOTENT CELL APART FROM THE ENDOMETRIUM, THAT 'ENDOMETRIUM-LIKE CELLS' CAN HARBOUR IMPORTANT G-E DIFFERENCES, AND THAT THE RISK IS HIGHER IN PREDISPOSED WOMEN WITH MORE INHERITED INCIDENTS. A CONSEQUENCE IS A HIGH RISK AFTER PUBERTY WHICH DECREASES PROGRESSIVELY THEREAFTER. CONSIDERING A 10-YEAR DELAY BETWEEN INITIATION AND PERFORMING A LAPAROSCOPY, THIS WAS OBSERVED IN THE UNITED ARAB EMIRATES, BELGIUM, FRANCE AND USA. THE SUBSEQUENT GROWTH VARIES WITH THE G-E CHANGES AND THE ENVIRONMENT BUT IS SELF-LIMITING PROBABLY BECAUSE OF THE IMMUNOLOGIC REACTION AND FIBROSIS. THAT EACH LESION HAS A DIFFERENT SET OF G-E INCIDENTS EXPLAINS THE VARIABILITY OF PAIN AND THE RESPONSE TO HORMONAL TREATMENT. NEW LESIONS MAY DEVELOP, BUT RECURRENCES AFTER SURGICAL EXCISION ARE RARE. THE FIBROSIS AROUND ENDOMETRIOSIS BELONGS TO THE BODY AND DOES NOT NEED TO BE REMOVED. THIS SUGGESTS CONSERVATIVE EXCISION OR MINIMAL BOWEL WITHOUT SAFETY MARGINS AND SUPERFICIAL TREATMENT OF OVARIAN ENDOMETRIOSIS. THIS G-E CONCEPT ALSO SUGGESTS PREVENTION BY DECREASING OXIDATIVE STRESS FROM RETROGRADE MENSTRUATION OR THE PERITONEAL MICROBIOME. THIS SUGGESTS THE PREVENTION OF VAGINAL INFECTIONS AND CHANGES IN THE GASTROINTESTINAL MICROBIOTA THROUGH FOOD INTAKE AND EXERCISE. IN CONCLUSION, A HIGHER RISK OF INITIATING ENDOMETRIOSIS DURING ADOLESCENCE WAS OBSERVED IN UAE, FRANCE, BELGIUM AND USA. THIS NEW UNDERSTANDING AND THE LIMITED GROWTH OPENS PERSPECTIVES FOR EARLIER DIAGNOSIS AND BETTER TREATMENT. 2022 11 4957 36 PATHOGENESIS OF ENDOMETRIOSIS: THE GENETIC/EPIGENETIC THEORY. OBJECTIVE: TO STUDY THE PATHOPHYSIOLOGY OF ENDOMETRIOSIS. DESIGN: OVERVIEW OF OBSERVATIONS ON ENDOMETRIOSIS. SETTING: NOT APPLICABLE. PATIENT(S): NONE. INTERVENTIONS(S): NONE. MAIN OUTCOME MEASURE(S): THE HYPOTHESIS IS COMPATIBLE WITH ALL OBSERVATIONS. RESULT(S): ENDOMETRIOSIS, ENDOMETRIUM-LIKE TISSUE OUTSIDE THE UTERUS, HAS A VARIABLE MACROSCOPIC APPEARANCE AND A POORLY UNDERSTOOD NATURAL HISTORY. IT IS A HEREDITARY AND HETEROGENEOUS DISEASE WITH MANY BIOCHEMICAL CHANGES IN THE LESIONS, WHICH ARE CLONAL IN ORIGIN. IT IS ASSOCIATED WITH PAIN, INFERTILITY, ADENOMYOSIS, AND CHANGES IN THE JUNCTIONAL ZONE, PLACENTATION, IMMUNOLOGY, PLASMA, PERITONEAL FLUID, AND CHRONIC INFLAMMATION OF THE PERITONEAL CAVITY. THE SAMPSON HYPOTHESIS OF IMPLANTED ENDOMETRIAL CELLS FOLLOWING RETROGRADE MENSTRUATION, ANGIOGENIC SPREAD, LYMPHOGENIC SPREAD, OR THE METAPLASIA THEORY CANNOT EXPLAIN ALL OBSERVATIONS IF METAPLASIA IS DEFINED AS CELLS WITH REVERSIBLE CHANGES AND AN ABNORMAL BEHAVIOR/MORPHOLOGY DUE TO THE ABNORMAL ENVIRONMENT. WE PROPOSE A POLYGENETIC/POLYEPIGENETIC MECHANISM. THE SET OF GENETIC AND EPIGENETIC INCIDENTS TRANSMITTED AT BIRTH COULD EXPLAIN THE HEREDITARY ASPECTS, THE PREDISPOSITION, AND THE ENDOMETRIOSIS-ASSOCIATED CHANGES IN THE ENDOMETRIUM, IMMUNOLOGY, AND PLACENTATION. TO DEVELOP TYPICAL, CYSTIC OVARIAN OR DEEP ENDOMETRIOSIS LESIONS, A VARIABLE SERIES OF ADDITIONAL TRANSMISSIBLE GENETIC AND EPIGENETIC INCIDENTS ARE REQUIRED TO OCCUR IN A CELL WHICH MAY VARY FROM ENDOMETRIAL TO STEM CELLS. SUBTLE LESIONS ARE VIEWED AS ENDOMETRIUM IN A DIFFERENT ENVIRONMENT UNTIL ADDITIONAL INCIDENTS OCCUR. TYPICAL CYSTIC OVARIAN OR DEEP ENDOMETRIOSIS LESIONS ARE HETEROGENEOUS AND REPRESENT THREE DIFFERENT DISEASES. CONCLUSION(S): THE GENETIC EPIGENETIC THEORY IS COMPATIBLE WITH ALL OBSERVATIONS ON ENDOMETRIOSIS. IMPLICATIONS FOR TREATMENT AND PREVENTION ARE DISCUSSED. 2019 12 5241 30 PROGESTERONE RESISTANCE IN ENDOMETRIOSIS: CURRENT EVIDENCE AND PUTATIVE MECHANISMS. ENDOMETRIOSIS IS AN ESTROGEN-DEPENDENT DISEASE CHARACTERIZED BY THE GROWTH OF ENDOMETRIAL-LIKE TISSUE OUTSIDE THE UTERUS. PROGESTINS ARE CURRENTLY THE MOST COMMONLY USED TREATMENT FOR ENDOMETRIOSIS BECAUSE OF THEIR EXCELLENT THERAPEUTIC EFFECTS AND LIMITED SIDE EFFECTS. HOWEVER, PROGESTINS HAVE BEEN UNSUCCESSFUL IN SOME SYMPTOMATIC PATIENTS. THE INABILITY OF THE ENDOMETRIUM TO RESPOND PROPERLY TO PROGESTERONE IS KNOWN AS PROGESTERONE RESISTANCE. AN INCREASING BODY OF EVIDENCE SUGGESTS THE LOSS OF PROGESTERONE SIGNALING AND THE EXISTENCE OF PROGESTERONE RESISTANCE IN ENDOMETRIOSIS. THE MECHANISMS OF PROGESTERONE RESISTANCE HAVE RECEIVED CONSIDERABLE SCHOLARLY ATTENTION IN RECENT YEARS. ABNORMAL PGR SIGNALING, CHRONIC INFLAMMATION, ABERRANT GENE EXPRESSION, EPIGENETIC ALTERATIONS, AND ENVIRONMENTAL TOXINS ARE CONSIDERED POTENTIAL MOLECULAR CAUSES OF PROGESTERONE RESISTANCE IN ENDOMETRIOSIS. THE GENERAL OBJECTIVE OF THIS REVIEW WAS TO SUMMARIZE THE EVIDENCE AND MECHANISMS OF PROGESTERONE RESISTANCE. A DEEPER UNDERSTANDING OF HOW THESE MECHANISMS CONTRIBUTE TO PROGESTERONE RESISTANCE MAY HELP DEVELOP A NOVEL THERAPEUTIC REGIMEN FOR WOMEN WITH ENDOMETRIOSIS BY REVERSING PROGESTERONE RESISTANCE. 2023 13 3820 25 INTRODUCTION TO PRECLINICAL EVIDENCE FROM ANIMAL MODELS OF ENDOMETRIOSIS. ENDOMETRIOSIS, THE PRESENCE AND GROWTH OF UTERINE ENDOMETRIAL GLANDULAR EPITHELIAL AND STROMA CELLS OUTSIDE THE UTERINE CAVITY, CAUSES PAIN AND INFERTILITY IN WOMEN AND GIRLS OF REPRODUCTIVE AGE. AS RANDOMIZED, DOUBLE-BLINDED, CONTROLLED STUDIES OF ENDOMETRIOSIS IN WOMEN ARE IMPRACTICAL AND AT TIMES ETHICALLY PROHIBITIVE, ANIMAL MODELS FOR ENDOMETRIOSIS AROSE AS AN IMPORTANT ADJUNCT TO GAIN MECHANISTIC INSIGHTS INTO THE ETIOLOGY AND PATHOPHYSIOLOGICAL MECHANISMS OF THIS PERPLEXING DISORDER. A MORE THOROUGH UNDERSTANDING OF ENDOMETRIOSIS IN WOMEN MAY HELP DEVELOP NOVEL NONINVASIVE DIAGNOSTICS, CLASSIFICATION SYSTEMS, THERAPEUTIC REGIMES, AND EVEN PREVENTATIVE METHODS FOR THE MANAGEMENT OF ENDOMETRIOSIS. THIS CHAPTER IS INTENDED TO INTRODUCE A BRIEF HISTORICAL BACKGROUND, BIOLOGICAL AND EPIDEMIOLOGICAL ASPECTS, THE MAJOR SYMPTOMS, THE EFFECTS OF ENDOCRINE-DISRUPTING CHEMICALS, AND AN EXAMPLE OF AN EPIGENETIC FACTOR OF ENDOMETRIOSIS IN WOMEN. 2020 14 1114 38 COMMONALITIES AND DISPARITIES BETWEEN ENDOMETRIOSIS AND CHRONIC ENDOMETRITIS: THERAPEUTIC POTENTIAL OF NOVEL ANTIBIOTIC TREATMENT STRATEGY AGAINST ECTOPIC ENDOMETRIUM. CHRONIC ENDOMETRITIS (CE) IS A LOCAL MUCOSAL INFLAMMATORY DISORDER OF THE UTERINE LINING, WHICH IS HISTOPATHOLOGICALLY RECOGNIZED AS THE UNUSUAL INFILTRATION OF CD138(+) PLASMACYTES INTO THE ENDOMETRIAL STROMAL COMPARTMENT. ACCUMULATING BODY OF RESEARCH DOCUMENTED THAT CE IS ASSOCIATED WITH FEMALE INFERTILITY AND SEVERAL OBSTETRIC/NEONATAL COMPLICATIONS. THE MAJOR CAUSE OF CE IS THOUGHT TO BE INTRAUTERINE INFECTION REPRESENTED BY COMMON BACTERIA (ESCHERICHIA COLI, ENTEROCOCCUS FAECALIS, STREPTOCOCCUS, AND STAPHYLOCOCCUS), MYCOPLASMA/UREAPLASMA, AND MYCOBACTERIUM. ADDITIONALLY, LOCAL DYSBIOSIS IN THE FEMALE REPRODUCTIVE TRACT MAY BE INVOLVED IN THE ONSET AND DEVELOPMENT OF CE. ANTIBIOTIC TREATMENTS AGAINST THESE MICROORGANISMS ARE EFFECTIVE IN THE ELIMINATION OF ENDOMETRIAL STROMAL PLASMACYTES IN THE AFFECTED PATIENTS. MEANWHILE, ENDOMETRIOSIS IS A COMMON FEMALE REPRODUCTIVE TRACT DISEASE CHARACTERIZED BY ENDOMETRIOTIC TISSUES (ECTOPIC ENDOMETRIUM) GROWING OUTSIDE THE UTERUS AND POTENTIALLY CAUSES CHRONIC PELVIC SYMPTOMS (DYSMENORRHEA, DYSPAREUNIA, DYSCHEZIA, AND DYSURIA), INFERTILITY, AND OVARIAN CANCERS. ENDOMETRIOSIS INVOLVES ENDOCRINOLOGICAL, GENETIC, AND EPIGENETIC FACTORS IN ITS ETIOLOGY AND PATHOGENESIS. RECENT STUDIES FOCUS ON IMMUNOLOGICAL, INFLAMMATORY, AND INFECTIOUS ASPECTS OF ENDOMETRIOSIS AND DEMONSTRATE SEVERAL COMMON CHARACTERISTICS BETWEEN ENDOMETRIOSIS AND CE. THIS REVIEW AIMED TO BETTER UNDERSTAND THE IMMUNOLOGICAL AND MICROBIAL BACKGROUNDS UNDERLYING ENDOMETRIOSIS AND CE AND LOOK INTO THE THERAPEUTIC POTENTIAL OF THE NOVEL ANTIBIOTIC TREATMENT STRATEGY AGAINST ENDOMETRIOSIS IN LIGHT OF ENDOMETRIAL INFECTIOUS DISEASE. 2023 15 146 37 ABERRANT ENDOMETRIAL DNA METHYLOME AND ASSOCIATED GENE EXPRESSION IN WOMEN WITH ENDOMETRIOSIS. ENDOMETRIOSIS IS AN ESTROGEN-DEPENDENT, PROGESTERONE-RESISTANT DISORDER LARGELY DERIVED FROM RETROGRADE TRANSPLANTATION OF MENSTRUAL TISSUE/CELLS INTO THE PELVIS, ELICITING AN INFLAMMATORY RESPONSE, PELVIC PAIN, AND INFERTILITY. EUTOPIC ENDOMETRIUM (WITHIN THE UTERUS), GIVING RISE TO PELVIC DISEASE, DISPLAYS CYCLE-DEPENDENT TRANSCRIPTOMIC, PROTEOMIC, AND SIGNALING ABNORMALITIES, AND ALTHOUGH ITS DNA METHYLATION PROFILES DYNAMICALLY CHANGE ACROSS THE CYCLE IN HEALTHY WOMEN, STUDIES IN ENDOMETRIOSIS ARE LIMITED. HEREIN, WE INVESTIGATED THE DNA METHYLOME AND ASSOCIATED GENE EXPRESSION IN THREE PHASES OF THE CYCLE IN EUTOPIC ENDOMETRIUM OF WOMEN WITH SEVERE ENDOMETRIOSIS VERSUS CONTROLS, MATCHED FOR ETHNICITY, MEDICATIONS, SMOKING, AND NO RECENT CONTRACEPTIVE STEROID USE. GENOME-WIDE DNA METHYLATION AND GENE EXPRESSION WERE COASSESSED IN EACH SAMPLE. CYCLE PHASE WAS DETERMINED BY HISTOLOGY, SERUM HORMONE LEVELS, AND UNSUPERVISED PRINCIPAL COMPONENT AND HIERARCHICAL CLUSTER ANALYSES OF MICROARRAY DATA. ALTERED ENDOMETRIAL DNA METHYLATION IN ENDOMETRIOSIS WAS MOST PROMINENT IN THE MIDSECRETORY PHASE (PEAK PROGESTERONE), WITH DISRUPTION OF THE NORMAL PATTERN OF CYCLE-DEPENDENT DNA METHYLATION CHANGES, INCLUDING A BIAS TOWARD METHYLATION OF CPG ISLANDS, SUGGESTING WIDE-RANGE ABNORMALITIES OF THE CHROMATIN REMODELING MACHINERY IN ENDOMETRIOSIS. DNA METHYLATION CHANGES WERE ASSOCIATED WITH ALTERED GENE EXPRESSION RELEVANT TO ENDOMETRIAL FUNCTION/DYSFUNCTION, INCLUDING CELL PROLIFERATION, INFLAMMATION/IMMUNE RESPONSE, ANGIOGENESIS, AND STEROID HORMONE RESPONSE. THE DATA PROVIDE INSIGHT INTO EPIGENETIC REPROGRAMMING AND STEROID HORMONE ACTIONS IN ENDOMETRIUM CONTRIBUTING TO THE PATHOGENESIS AND PATHOPHYSIOLOGY OF ENDOMETRIOSIS. 2016 16 1889 28 ENDOMETRIOSIS MALIGNANT TRANSFORMATION: EPIGENETICS AS A PROBABLE MECHANISM IN OVARIAN TUMORIGENESIS. ENDOMETRIOSIS, DEFINED AS THE PRESENCE OF ECTOPIC ENDOMETRIAL GLANDS AND STROMA OUTSIDE THE UTERINE CAVITY, IS A CHRONIC, HORMONE-DEPENDENT GYNECOLOGIC DISEASE AFFECTING MILLIONS OF WOMEN ACROSS THE WORLD, WITH SYMPTOMS INCLUDING CHRONIC PELVIC PAIN, DYSMENORRHEA, DYSPAREUNIA, DYSURIA, AND SUBFERTILITY. IN ADDITION, THERE IS WELL-ESTABLISHED EVIDENCE THAT, ALTHOUGH ENDOMETRIOSIS IS CONSIDERED BENIGN, IT IS ASSOCIATED WITH AN INCREASED RISK OF MALIGNANT TRANSFORMATION, WITH THE INVOLVEMENT OF VARIOUS MECHANISMS OF DEVELOPMENT. MORE AND MORE EVIDENCE REVEALS AN IMPORTANT CONTRIBUTION OF EPIGENETIC MODIFICATION NOT ONLY IN ENDOMETRIOSIS BUT ALSO IN MECHANISMS OF ENDOMETRIOSIS MALIGNANT TRANSFORMATION, INCLUDING DNA METHYLATION AND DEMETHYLATION, HISTONE MODIFICATIONS, AND MIRNA ABERRANT EXPRESSIONS. IN THIS PRESENT REVIEW, WE MAINLY SUMMARIZE THE RESEARCH PROGRESS ABOUT THE CURRENT KNOWLEDGE REGARDING THE EPIGENETIC MODIFICATIONS OF THE RELATIONS BETWEEN ENDOMETRIOSIS MALIGNANT TRANSFORMATION AND OVARIAN CANCER IN AN EFFORT TO IDENTIFY SOME RISK FACTORS PROBABLY ASSOCIATED WITH ECTOPIC ENDOMETRIUM TRANSFORMATION. 2018 17 2602 27 EPIGENETICS, ENDOMETRIOSIS AND SEX STEROID RECEPTORS: AN UPDATE ON THE EPIGENETIC REGULATORY MECHANISMS OF ESTROGEN AND PROGESTERONE RECEPTORS IN PATIENTS WITH ENDOMETRIOSIS. ENDOMETRIOSIS IS A BENIGN GYNECOLOGICAL DISEASE AFFECTING APPROXIMATELY 10% OF REPRODUCTIVE-AGED WOMEN AND IS DEFINED AS THE PRESENCE OF ENDOMETRIAL GLANDS AND STROMA OUTSIDE THE UTERINE CAVITY. ENDOMETRIOSIS CAN CAUSE A VARIETY OF HEALTH PROBLEMS, FROM PELVIC DISCOMFORT TO CATAMENIAL PNEUMOTHORAX, BUT IT'S MAINLY LINKED WITH SEVERE AND CHRONIC PELVIC PAIN, DYSMENORRHEA, AND DEEP DYSPAREUNIA, AS WELL AS REPRODUCTIVE ISSUES. THE PATHOGENESIS OF ENDOMETRIOSIS INVOLVES AN ENDOCRINE DYSFUNCTION, WITH ESTROGEN DEPENDENCY AND PROGESTERONE RESISTANCE, AND INFLAMMATORY MECHANISM ACTIVATION, TOGETHER WITH IMPAIRED CELL PROLIFERATION AND NEUROANGIOGENESIS. THE PRESENT CHAPTER AIMS TO DISCUSS THE MAIN EPIGENETIC MECHANISMS RELATED TO ESTROGEN RECEPTORS (ERS) AND PROGESTERONE RECEPTORS (PRS) IN PATIENTS WITH ENDOMETRIOSIS. THERE ARE NUMEROUS EPIGENETIC MECHANISMS PARTICIPATING IN ENDOMETRIOSIS, REGULATING THE EXPRESSION OF THE GENES ENCODING THESE RECEPTORS BOTH INDIRECTLY, THROUGH THE REGULATION OF TRANSCRIPTION FACTORS, AND DIRECTLY, THROUGH DNA METHYLATION, HISTONE MODIFICATIONS, MICRO RNAS AND LONG NONCODING RNAS. THIS REPRESENTS AN OPEN FIELD OF INVESTIGATION, WHICH MAY LEAD TO IMPORTANT CLINICAL IMPLICATIONS SUCH AS THE DEVELOPMENT OF EPIGENETIC DRUGS FOR THE TREATMENT OF ENDOMETRIOSIS AND THE IDENTIFICATION OF SPECIFIC AND EARLY BIOMARKERS FOR THE DISEASE. 2023 18 6272 29 THE ORIGIN AND PATHOGENESIS OF ENDOMETRIOSIS. RECENT MOLECULAR GENETIC FINDINGS ON ENDOMETRIOSIS AND NORMAL ENDOMETRIUM SUGGEST A MODIFIED MODEL IN WHICH CIRCULATING EPITHELIAL PROGENITOR OR STEM CELLS INTENDED TO REGENERATE UTERINE ENDOMETRIUM AFTER MENSTRUATION MAY BECOME OVERREACTIVE AND TRAPPED OUTSIDE THE UTERUS. THESE TRAPPED EPITHELIUM-COMMITTED PROGENITOR CELLS FORM NASCENT GLANDS THROUGH CLONAL EXPANSION AND RECRUIT POLYCLONAL STROMAL CELLS, LEADING TO THE ESTABLISHMENT OF DEEP INFILTRATING ENDOMETRIOSIS. ONCE FORMED, THE ECTOPIC TISSUE BECOMES SUBJECT TO IMMUNE SURVEILLANCE, RESULTING IN CHRONIC INFLAMMATION. THE INFLAMMATORY RESPONSE ORCHESTRATED BY NUCLEAR FACTOR-KAPPAB SIGNALING IS EXACERBATED BY ABERRATIONS IN THE ESTROGEN RECEPTOR-BETA AND PROGESTERONE RECEPTOR PATHWAYS, WHICH ARE ALSO AFFECTED BY LOCAL INFLAMMATION, FORMING A DYSREGULATED INFLAMMATION-HORMONAL LOOP. GLANDULAR EPITHELIUM WITHIN ENDOMETRIOTIC TISSUE HARBORS CANCER-ASSOCIATED MUTATIONS THAT ARE FREQUENTLY DETECTED IN ENDOMETRIOSIS-RELATED OVARIAN CANCERS. IN THIS REVIEW, WE SUMMARIZE RECENT ADVANCES THAT HAVE ILLUMINATED THE ORIGIN AND PATHOGENESIS OF ENDOMETRIOSIS AND HAVE PROVIDED NEW AVENUES FOR RESEARCH THAT PROMISE TO IMPROVE THE EARLY DIAGNOSIS AND MANAGEMENT OF ENDOMETRIOSIS. 2020 19 3999 28 LOSS OF HDAC3 RESULTS IN NONRECEPTIVE ENDOMETRIUM AND FEMALE INFERTILITY. ENDOMETRIOSIS IS A DISEASE IN WHICH TISSUE THAT NORMALLY GROWS INSIDE THE UTERUS GROWS OUTSIDE THE UTERUS AND CAUSES CHRONIC PELVIC PAIN AND INFERTILITY. HOWEVER, THE EXACT MECHANISMS OF THE PATHOGENESIS OF ENDOMETRIOSIS-ASSOCIATED INFERTILITY ARE UNKNOWN. EPIGENETIC DYSREGULATION HAS RECENTLY BEEN IMPLICATED IN INFERTILITY. HERE, WE REPORT A REDUCTION OF HISTONE DEACETYLASE 3 (HDAC3) PROTEIN AMOUNTS IN EUTOPIC ENDOMETRIUM OF INFERTILE WOMEN WITH ENDOMETRIOSIS COMPARED TO A CONTROL GROUP. TO INVESTIGATE THE EFFECT OF HDAC3 LOSS IN THE UTERUS, WE GENERATED MICE WITH CONDITIONAL ABLATION OF HDAC3 IN PROGESTERONE RECEPTOR (PGR)-POSITIVE CELLS (PGR(CRE/+)HDAC3(F/F) ; HDAC3(D/D) ). LOSS OF HDAC3 IN THE UTERUS OF MICE RESULTS IN INFERTILITY DUE TO IMPLANTATION FAILURE AND DECIDUALIZATION DEFECT. EXPRESSION MICROARRAY AND CHIP-SEQ ANALYSES IDENTIFIED COL1A1 AND COL1A2 AS DIRECT TARGETS OF HDAC3 IN BOTH MICE AND HUMANS. REDUCTION OF HDAC3 ABROGATED DECIDUALIZATION IN A PRIMARY CULTURE OF HUMAN ENDOMETRIAL STROMAL CELLS (HESCS) SIMILAR TO THAT OBSERVED IN INFERTILE PATIENTS WITH ENDOMETRIOSIS. WHEREAS ATTENUATION OF HDAC3 RESULTED IN P300 RECRUITMENT TO COL1A1 AND COL1A2 GENES IN THE UTERUS OF MICE AS WELL AS HESCS, INHIBITION OF P300 PERMITTED HESCS TO UNDERGO DECIDUALIZATION. COLLECTIVELY, WE FOUND ATTENUATION OF HDAC3 AND OVEREXPRESSION OF COLLAGEN TYPE I IN THE EUTOPIC ENDOMETRIUM OF INFERTILE PATIENTS WITH ENDOMETRIOSIS. HDAC3 LOSS CAUSED A DEFECT OF DECIDUALIZATION THROUGH THE ABERRANT TRANSCRIPTIONAL ACTIVATION OF COL1A1 AND COL1A2 GENES IN MICE AND COL1A1 AND COL1A2 GENES IN HUMANS. OUR RESULTS SUGGEST THAT HDAC3 IS CRITICAL FOR ENDOMETRIAL RECEPTIVITY AND DECIDUALIZATION. 2019 20 3509 20 IDENTIFYING MECHANISMS OF ENDOMETRIOSIS-ASSOCIATED REDUCED FECUNDITY IN A RAT MODEL: NOVEL INSIGHTS TOWARD UNDERSTANDING HUMAN INFERTILITY. THE EXISTENCE OF ENDOMETRIOSIS HAS BEEN KNOWN SINCE AT LEAST THE NINETEENTH CENTURY, YET THE LACK OF UNDERSTANDING OF CAUSES OF INFERTILITY AND THEREFORE INADEQUATE TREATMENT APPROACHES IN ENDOMETRIOSIS CREATES A SIGNIFICANT CHALLENGE IN REPRODUCTIVE MEDICINE. WOMEN WORLDWIDE SUFFER NOT ONLY PAIN AND INFERTILITY BUT ALSO ECONOMICAL, SOCIETAL, AND PHYSIOLOGICAL BURDENS. STUDIES OF REPRODUCTIVE EVENTS IN WOMEN ARE DIFFICULT TO CONDUCT DUE TO A HOST OF CONFOUNDING PERSONAL AND ENVIRONMENTAL FACTORS AND ETHICALLY LIMITED DUE TO THE VERY NATURE OF WORKING WITH REPRODUCTIVE TISSUES AND CELLS, ESPECIALLY EMBRYOS. ANIMAL MODELS ARE A VIABLE ADJUNCT TO STUDY MECHANISMS CAUSING HUMAN REPRODUCTIVE ANOMALIES AND INFERTILITY IN ENDOMETRIOSIS. THIS CHAPTER DISCUSSES REPRODUCTIVE ANOMALIES CAUSING INFERTILITY IN ENDOMETRIOSIS AND WELL-ESTABLISHED ANIMAL MODELS WHICH HELP DECIPHER THE PROBLEMS AND LEAD TO HERETOFORE UNKNOWN NONSURGICAL, NONHORMONAL METHODS TO MANAGE ENDOMETRIOSIS IN WOMEN. IN ADDITION, STUDIES OF EFFECTS OF DEVELOPMENTAL EXPOSURE TO ENDOMETRIOSIS ARE REVEALING FOR THE FIRST TIME, IN BOTH FEMALE AND MALE OFFSPRING, TRANSGENERATIONAL SUBFERTILITY IN A RAT MODEL PROVIDING INSIGHTS INTO THE FAMILIAL NATURE OF ENDOMETRIOSIS AND POSSIBLE EPIGENETIC INVOLVEMENT. 2020