1 4274 146 MICROBIOTA IN INFLAMMATORY BOWEL DISEASE PATHOGENESIS AND THERAPY: IS IT ALL ABOUT DIET? INFLAMMATORY BOWEL DISEASE (IBD), INCLUDING ULCERATIVE COLITIS, CROHN'S DISEASE, AND UNCLASSIFIED IBD, CONTINUES TO CAUSE SIGNIFICANT MORBIDITY. WHILE ITS INCIDENCE IS INCREASING, NO CLEAR ETIOLOGY AND NO CURE HAVE YET BEEN DISCOVERED. RECENT FINDINGS SUGGEST THAT IBD MAY HAVE A MULTIFACTORIAL ETIOLOGY, WHERE COMPLEX INTERACTIONS BETWEEN GENETICS, EPIGENETICS, ENVIRONMENTAL FACTORS (INCLUDING DIET BUT ALSO INFECTIONS, ANTIBIOTICS, AND SANITATION), AND HOST IMMUNE SYSTEM LEAD TO ABNORMAL IMMUNE RESPONSES AND CHRONIC INFLAMMATION. OVER THE PAST YEARS, THE ROLE OF ALTERED GUT MICROBIOTA (IN BOTH COMPOSITION AND FUNCTION) IN IBD PATHOGENESIS HAS EMERGED AS AN OUTSTANDING AREA OF INTEREST. ACCORDING TO NEW FINDINGS, GUT DYSBIOSIS MAY APPEAR AS A KEY ELEMENT IN INITIATION OF INFLAMMATION IN IBD AND ITS COMPLICATIONS. MOREOVER, COMPLEX METAGENOMIC STUDIES PROVIDE POSSIBILITIES TO DISTINGUISH BETWEEN IBD TYPES AND APPRECIATE SEVERITY AND PROGNOSIS OF THE DISEASE, AS WELL AS RESPONSE TO THERAPY. THIS REVIEW PROVIDES AN UPDATED KNOWLEDGE OF RECENT FINDINGS LINKING ALTERED BACTERIAL COMPOSITION AND FUNCTIONS, VIRUSES, AND FUNGI TO IBD PATHOGENESIS. IT ALSO HIGHLIGHTS THE COMPLEX GENETIC, EPIGENETIC, IMMUNE, AND MICROBIAL INTERACTIONS IN RELATION TO ENVIRONMENTAL FACTORS (INCLUDING DIET). WE OVERVIEW THE ACTUAL OPTIONS TO MANIPULATE THE ALTERED MICROBIOTA, SUCH AS MODIFIED DIET, PROBIOTICS, PREBIOTICS, SYNBIOTICS, ANTIBIOTICS, AND FECAL TRANSPLANTATION. FUTURE POSSIBLE THERAPIES ARE ALSO INCLUDED. TARGETING ALTERED MICROBIOTA COULD BE THE NEXT THERAPEUTIC PERSONALIZED APPROACH, BUT MORE RESEARCH AND WELL-DESIGNED COMPARATIVE PROSPECTIVE STUDIES ARE REQUIRED TO FORMULATE ADEQUATE DIRECTIONS FOR PREVENTION AND THERAPY. 2015 2 3692 41 INFLAMMATORY BOWEL DISEASES: THE ROLE OF GUT MICROBIOTA. INFLAMMATORY BOWEL DISEASES (IBD) ARE CHRONIC MULTIFACTORIAL DISEASES CHARACTERIZED BY PARTIALLY UNCLEAR PATHOGENIC MECHANISMS INCLUDING CHANGES IN INTESTINAL MICROBIOTA. DESPITE THE MICROBIOTA, ALTERATION IS WELL ESTABLISHED IN IBD PATIENTS, AS REPORTED BY 16RNA SEQUENCING ANALYSIS, AN IMPORTANT GOAL IS TO DEFINE IF IT IS JUST A CONSEQUENCE OF THE DISEASE PROGRESSION OR A TRIGGER FACTOR OF THE DISEASE ITSELF. TO DATE, GUT MICROBIOTA COMPOSITION AND GUT MICROBIOTA-RELATED METABOLITES SEEM TO AFFECT THE HOST HEALTHY STATE BOTH BY MODULATING METABOLIC PATHWAYS OR ACTING ON THE EXPRESSION OF DIFFERENT GENES THROUGH EPIGENETIC EFFECTS. BECAUSE OF THIS, IT HAS BEEN SUGGESTED THAT INTESTINAL MICROBIOTA MIGHT REPRESENT A PROMISING THERAPEUTIC TARGET FOR IBD PATIENTS. THE AIM OF THIS REVIEW IS TO SUMMARIZE BOTH THE MOST RECENT ACQUISITIONS IN THE FIELD OF GUT MICROBIOTA AND ITS INVOLVEMENT IN INTESTINAL INFLAMMATION TOGETHER WITH THE AVAILABLE STRATEGIES FOR THE MODULATION OF MICROBIOTA, SUCH AS PREBIOTICS AND/OR PROBIOTICS ADMINISTRATION OR FECAL MICROBIOTA TRANSPLANTATION. 2020 3 566 45 BASES FOR THE ADEQUATE DEVELOPMENT OF NUTRITIONAL RECOMMENDATIONS FOR PATIENTS WITH INFLAMMATORY BOWEL DISEASE. INFLAMMATORY BOWEL DISEASE (IBD) IS A CHRONIC AND RELAPSING INFLAMMATORY CONDITION OF THE GASTROINTESTINAL TRACT; IT IS A HETEROGENEOUS AND MULTIFACTORIAL DISORDER RESULTING FROM A COMPLEX INTERPLAY BETWEEN GENETIC VARIATION, INTESTINAL MICROBIOTA, THE HOST IMMUNE SYSTEM AND ENVIRONMENTAL FACTORS SUCH AS DIET, DRUGS, BREASTFEEDING AND SMOKING. THE INTERACTIONS BETWEEN DIETARY NUTRIENTS AND INTESTINAL IMMUNITY ARE COMPLEX. THERE IS A COMPELLING ARGUMENT FOR ENVIRONMENTAL FACTORS SUCH AS DIET PLAYING A ROLE IN THE CAUSE AND COURSE OF IBD, GIVEN THAT THREE IMPORTANT FACTORS IN THE PATHOGENESIS OF IBD CAN BE MODULATED AND CONTROLLED BY DIET: INTESTINAL MICROBIOTA, THE IMMUNE SYSTEM AND EPITHELIAL BARRIER FUNCTION. THE AIM OF THIS REVIEW IS TO SUMMARIZE THE EPIDEMIOLOGICAL FINDINGS REGARDING DIET AND TO FOCUS ON THE EFFECTS THAT NUTRIENTS EXERT ON THE INTESTINAL MUCOSA-MICROBIOTA-PERMEABILITY INTERACTION. THE NATURE OF THESE INTERACTIONS IN IBD IS INFLUENCED BY ALTERATIONS IN THE NUTRITIONAL METABOLISM OF THE GUT MICROBIOTA AND HOST CELLS THAT CAN INFLUENCE THE OUTCOME OF NUTRITIONAL INTERVENTION. A BETTER UNDERSTANDING OF DIET-HOST-MICROBIOTA INTERACTIONS IS ESSENTIAL FOR UNRAVELLING THE COMPLEX MOLECULAR BASIS OF EPIGENETIC, GENETIC AND ENVIRONMENTAL INTERACTIONS UNDERLYING IBD PATHOGENESIS AS WELL AS FOR OFFERING NEW THERAPEUTIC APPROACHES FOR THE TREATMENT OF IBD. 2019 4 1404 38 DIETARY COMPOSITION AND EFFECTS IN INFLAMMATORY BOWEL DISEASE. DRAMATIC CHANGES IN THE ENVIRONMENT AND HUMAN LIFESTYLE HAVE BEEN ASSOCIATED WITH THE RISE OF VARIOUS CHRONIC COMPLEX DISEASES, SUCH AS INFLAMMATORY BOWEL DISEASE (IBD). A DYSBIOTIC GUT MICROBIOTA HAS BEEN PROPOSED AS A CRUCIAL PATHOGENIC ELEMENT, CONTRIBUTING TO IMMUNE IMBALANCES AND FOSTERING A PROINFLAMMATORY MILIEU, WHICH MAY BE ASSOCIATED WITH DISEASE RELAPSES OR EVEN THE INITIATION OF IBD. IN ADDITION TO REPRESENTING IMPORTANT REGULATORS OF THE MUCOSAL IMMUNITY AND THE COMPOSITION OF THE GUT MICROBIOTA, FOOD COMPONENTS HAVE BEEN SHOWN TO BE POTENTIAL ENVIRONMENTAL TRIGGERS OF EPIGENETIC MODIFICATIONS. IN THE CONTEXT OF CHRONIC INTESTINAL INFLAMMATION, DIETARY HABITS AND SPECIFIC FOOD COMPONENTS HAVE BEEN IMPLICATED AS IMPORTANT MODULATORS OF EPIGENETIC MECHANISMS, INCLUDING DNA METHYLATION, WHICH MAY PREDISPOSE A PERSON TO THE INCREASED RISK OF THE INITIATION AND EVOLUTION OF IBD. THIS REVIEW PROVIDES NOVEL INSIGHTS ABOUT HOW DIETARY FACTORS MAY INTERACT WITH THE INTESTINAL MUCOSA AND MODULATE IMMUNE HOMEOSTASIS BY SHAPING THE INTESTINAL ECOSYSTEM, AS WELL AS THE POTENTIAL INFLUENCE OF DIET IN THE ETIOPATHOGENESIS AND MANAGEMENT OF IBD. 2019 5 2675 43 ETIOPATHOGENESIS OF INFLAMMATORY BOWEL DISEASE: TODAY AND TOMORROW. PURPOSE OF REVIEW: CROHN'S DISEASE AND ULCERATIVE COLITIS, THE TWO MAJOR FORMS OF INFLAMMATORY BOWEL DISEASE (IBD), REPRESENT CHRONIC DISEASES OF UNKNOWN CAUSE, AND THEY ARE REGARDED AS PROTOTYPICAL COMPLEX DISEASES. DESPITE ALL THE RECENT ADVANCES, A COMPLETE APPRECIATION OF THE PATHOGENESIS OF IBD IS STILL LIMITED. IN THIS REVIEW, WE PRESENT RECENT INFORMATION CONTRIBUTING TO A BETTER UNDERSTANDING OF MECHANISMS UNDERLYING IBD. RECENT FINDINGS: HERE, WE ATTEMPT TO HIGHLIGHT NOVEL ENVIRONMENTAL TRIGGERS, DATA ON THE GUT MICROBIOTA, ITS INTERACTION WITH THE HOST, AND THE POTENTIAL INFLUENCE OF DIET AND FOOD COMPONENTS. WE DISCUSS RECENT FINDINGS ON DEFECTIVE SIGNALING PATHWAYS AND THE POTENTIAL EFFECTS ON THE IMMUNE RESPONSE, AND WE PRESENT NEW DATA ON EPIGENETIC CHANGES, INFLAMMASOME, AND DAMAGE-ASSOCIATED MOLECULAR PATTERNS ASSOCIATED WITH IBD. SUMMARY: THE CONTINUING IDENTIFICATION OF SEVERAL EPIGENETIC, TRANSCRIPTOMIC, PROTEOMIC, AND METABOLOMIC ALTERATIONS IN PATIENTS WITH IBD REFLECTS THE COMPLEX NATURE OF THE DISEASE AND SUGGESTS THE NEED FOR INNOVATIVE APPROACHES SUCH AS SYSTEMS BIOLOGY FOR IDENTIFYING NOVEL RELEVANT TARGETS IN IBD. 2017 6 3541 39 IMMUNOEPIGENETIC REGULATION OF INFLAMMATORY BOWEL DISEASE: CURRENT INSIGHTS INTO NOVEL EPIGENETIC MODULATIONS OF THE SYSTEMIC IMMUNE RESPONSE. THE IMMUNE SYSTEM AND ENVIRONMENTAL FACTORS ARE INVOLVED IN VARIOUS DISEASES, SUCH AS INFLAMMATORY BOWEL DISEASE (IBD), THROUGH THEIR EFFECT ON GENETICS, WHICH MODULATES IMMUNE CELLS. IBD ENCOMPASSES TWO MAIN PHENOTYPES, CROHN'S DISEASE, AND ULCERATIVE COLITIS, WHICH ARE MANIFESTED AS CHRONIC AND SYSTEMIC RELAPSE-REMITTING GASTROINTESTINAL TRACT DISORDERS WITH RISING GLOBAL INCIDENCE AND PREVALENCE. THE PATHOPHYSIOLOGY OF IBD IS COMPLEX AND NOT FULLY UNDERSTOOD. EPIGENETIC RESEARCH HAS RESULTED IN VALUABLE INFORMATION FOR UNRAVELING THE ETIOLOGY OF THIS IMMUNE-MEDIATED DISEASE. THUS, THE MAIN OBJECTIVE OF THE PRESENT REVIEW IS TO SUMMARIZE THE CURRENT FINDINGS ON THE ROLE OF EPIGENETIC MECHANISMS IN IBD TO SHED LIGHT ON THEIR POTENTIAL CLINICAL RELEVANCE. THIS REVIEW FOCUSES ON THE LATEST EVIDENCE REGARDING PERIPHERAL BLOOD MONONUCLEAR CELLS AND EPIGENETIC CHANGES IN HISTONE MODIFICATION, DNA METHYLATION, AND TELOMERE SHORTENING IN IBD. THE VARIOUS IDENTIFIED EPIGENETIC DNA PROFILES WITH CLINICAL VALUE IN IBD COULD BE USED AS BIOMARKERS FOR MORE ACCURATELY PREDICTING DISEASE DEVELOPMENT, TREATMENT RESPONSE, AND THERAPY-RELATED ADVERSE EVENTS. ULTIMATELY, THE INFORMATION PRESENTED HERE COULD BE OF POTENTIAL RELEVANCE FOR FUTURE CLINICAL PRACTICE IN DEVELOPING MORE EFFICIENT AND PRECISE MEDICINE TO IMPROVE THE QUALITY OF LIFE FOR PATIENTS WITH IBD. 2023 7 5540 38 ROLE OF DIET AND GUT MICROBIOTA ON COLORECTAL CANCER IMMUNOMODULATION. COLORECTAL CANCER (CRC) IS ONE OF THE MOST COMMONLY DIAGNOSED CANCERS, AND IT IS CHARACTERIZED BY GENETIC AND EPIGENETIC ALTERATIONS, AS WELL AS BY INFLAMMATORY CELL INFILTRATION AMONG MALIGNANT AND STROMAL CELLS. HOWEVER, THIS DYNAMIC INFILTRATION CAN BE INFLUENCED BY THE MICROENVIRONMENT TO PROMOTE TUMOR PROLIFERATION, SURVIVAL AND METASTASIS OR CANCER INHIBITION. IN PARTICULAR, THE CANCER MICROENVIRONMENT METABOLITES CAN REGULATE THE INFLAMMATORY CELLS TO INDUCE A CHRONIC INFLAMMATORY RESPONSE THAT CAN BE A PREDISPOSING CONDITION FOR CRC RETENTION. IN ADDITION, SOME NUTRITIONAL COMPONENTS MIGHT CONTRIBUTE TO A CHRONIC INFLAMMATORY CONDITION BY REGULATING VARIOUS IMMUNE AND INFLAMMATORY PATHWAYS. BESIDES THAT, DIET STRONGLY MODULATES THE GUT MICROBIOTA COMPOSITION, WHICH HAS A KEY ROLE IN MAINTAINING GUT HOMEOSTASIS AND IS ASSOCIATED WITH THE MODULATION OF HOST INFLAMMATORY AND IMMUNE RESPONSES. THEREFORE, DIET HAS A FUNDAMENTAL ROLE IN CRC INITIATION, PROGRESSION AND PREVENTION. IN PARTICULAR, FUNCTIONAL FOODS SUCH AS PROBIOTICS, PREBIOTICS AND SYMBIOTICS CAN HAVE A POTENTIALLY POSITIVE EFFECT ON HEALTH BEYOND BASIC NUTRITION AND HAVE ANTI-INFLAMMATORY EFFECTS. IN THIS REVIEW, WE DISCUSS THE INFLUENCE OF DIET ON GUT MICROBIOTA COMPOSITION, FOCUSING ON ITS ROLE ON GUT INFLAMMATION AND IMMUNITY. FINALLY, WE DESCRIBE THE POTENTIAL BENEFITS OF USING PROBIOTICS AND PREBIOTICS TO MODULATE THE HOST INFLAMMATORY RESPONSE, AS WELL AS ITS APPLICATION IN CRC PREVENTION AND TREATMENT. 2019 8 3585 41 IMPACT OF THE EXPOSOME ON THE EPIGENOME IN INFLAMMATORY BOWEL DISEASE PATIENTS AND ANIMAL MODELS. INFLAMMATORY BOWEL DISEASES (IBD) ARE CHRONIC INFLAMMATORY DISORDERS OF THE GASTROINTESTINAL TRACT THAT ENCOMPASS TWO MAIN PHENOTYPES, NAMELY CROHN'S DISEASE AND ULCERATIVE COLITIS. THESE CONDITIONS OCCUR IN GENETICALLY PREDISPOSED INDIVIDUALS IN RESPONSE TO ENVIRONMENTAL FACTORS. EPIGENETICS, ACTING BY DNA METHYLATION, POST-TRANSLATIONAL HISTONES MODIFICATIONS OR BY NON-CODING RNAS, COULD EXPLAIN HOW THE EXPOSOME (OR ALL ENVIRONMENTAL INFLUENCES OVER THE LIFE COURSE, FROM CONCEPTION TO DEATH) COULD INFLUENCE THE GENE EXPRESSION TO CONTRIBUTE TO INTESTINAL INFLAMMATION. WE PERFORMED A SCOPING SEARCH USING MEDLINE TO IDENTIFY ALL THE ELEMENTS OF THE EXPOSOME THAT MAY PLAY A ROLE IN INTESTINAL INFLAMMATION THROUGH EPIGENETIC MODIFICATIONS, AS WELL AS THE UNDERLYING MECHANISMS. THE ENVIRONMENTAL FACTORS EPIGENETICALLY INFLUENCING THE OCCURRENCE OF INTESTINAL INFLAMMATION ARE THE MATERNAL LIFESTYLE (MAINLY DIET, THE OCCURRENCE OF INFECTION DURING PREGNANCY AND SMOKING); BREASTFEEDING; MICROBIOTA; DIET (INCLUDING A LOW-FIBER DIET, HIGH-FAT DIET AND DEFICIENCY IN MICRONUTRIENTS); SMOKING HABITS, VITAMIN D AND DRUGS (E.G., IBD TREATMENTS, ANTIBIOTICS AND PROBIOTICS). INFLUENCED BY BOTH MICROBIOTA AND DIET, SHORT-CHAIN FATTY ACIDS ARE GUT MICROBIOTA-DERIVED METABOLITES RESULTING FROM THE ANAEROBIC FERMENTATION OF NON-DIGESTIBLE DIETARY FIBERS, PLAYING AN EPIGENETICALLY MEDIATED ROLE IN THE INTEGRITY OF THE EPITHELIAL BARRIER AND IN THE DEFENSE AGAINST INVADING MICROORGANISMS. ALTHOUGH THE IMPACT OF SOME ENVIRONMENTAL FACTORS HAS BEEN IDENTIFIED, THE EXPOSOME-INDUCED EPIMUTATIONS IN IBD REMAIN A LARGELY UNDEREXPLORED FIELD. HOW THESE ENVIRONMENTAL EXPOSURES INDUCE EPIGENETIC MODIFICATIONS (IN TERMS OF DURATION, FREQUENCY AND THE TIMING AT WHICH THEY OCCUR) AND HOW OTHER ENVIRONMENTAL FACTORS ASSOCIATED WITH IBD MODULATE EPIGENETICS DESERVE TO BE FURTHER INVESTIGATED. 2022 9 3920 35 LINKING IMMUNITY, EPIGENETICS, AND CANCER IN INFLAMMATORY BOWEL DISEASE. MOST OF WHAT IS KNOWN ABOUT THE PATHOGENESIS OF INFLAMMATORY BOWEL DISEASE (IBD) PERTAINS TO COMPLEX INTERPLAY BETWEEN HOST GENETICS, IMMUNITY, AND ENVIRONMENTAL FACTORS. EPIGENETIC MODIFICATIONS PLAY PIVOTAL ROLES IN INTESTINAL IMMUNITY AND MUCOSAL HOMEOSTASIS AS WELL AS MEDIATING GENE-ENVIRONMENT INTERACTIONS. IN THIS ARTICLE, WE PROVIDE A HISTORICAL ACCOUNT OF EPIGENETIC RESEARCH EITHER DIRECTLY RELATED OR PERTINENT TO THE PATHOGENESIS AND MANAGEMENT OF IBD. WE FURTHER COLLATE EMERGING EVIDENCE SUPPORTING ROLES FOR EPIGENETIC MECHANISMS IN RELEVANT ASPECTS OF IBD BIOLOGY, INCLUDING DEREGULATED IMMUNITY, HOST-PATHOGEN RECOGNITION AND MUCOSAL INTEGRITY. FINALLY, WE HIGHLIGHT KEY EPIGENETIC MECHANISMS THAT LINK CHRONIC INFLAMMATION TO SPECIFIC IBD COMORBIDITIES, INCLUDING COLITIS-ASSOCIATED CANCER AND DISCUSS THEIR POTENTIAL UTILITY AS NOVEL BIOMARKERS OR PHARMACOLOGIC TARGETS IN IBD THERAPY. 2014 10 3016 45 GENETICS AND EPIGENETICS OF IBD. INFLAMMATORY BOWEL DISEASES (IBD) ARE CHRONIC INTERMITTENT INFLAMMATORY DISORDERS OF THE GASTROINTESTINAL TRACT OF UNKNOWN ETIOLOGY BUT A CLEAR GENETIC PREDISPOSITION. PROMPTED BY THE FIRST INVESTIGATIONS ON IBD FAMILIES AND TWINS, THE GENETIC AND EPIGENETIC STUDIES HAVE PRODUCED AN UNPRECEDENTED AMOUNT OF INFORMATION IN COMPARISON WITH OTHER IMMUNE-MEDIATED OR COMPLEX DISEASES. NEW INFLAMMATORY PATHWAYS AND POSSIBLE MECHANISMS OF ACTION HAVE BEEN DISCLOSED, POTENTIALLY LEADING TO NEW-TARGETED THERAPY. HOWEVER, THE IDENTIFICATION OF GENETIC MARKERS DUE TO THE GREAT DISEASE HETEROGENEITY AND THE OVERWHELMING CONTRIBUTION OF ENVIRONMENTAL RISK FACTORS HAS NOT MODIFIED YET THE DISEASE MANAGEMENT. THE POSSIBILITY FOR THE FUTURE OF A BETTER PREDICTION OF DISEASE COURSE, RESPONSE TO THERAPY AND THERAPY-RELATED ADVERSE EVENTS MAY ALLOW A MORE EFFICIENT AND PERSONALIZED STRATEGY. THIS REVIEW WILL FOCUS ON MORE RECENT DISCOVERIES THAT MAY POTENTIALLY BE OF RELEVANCE IN DAILY CLINICAL PRACTICE. 2020 11 3172 45 GUT MICROBIOTA AND RISK OF DEVELOPING CELIAC DISEASE. GUT MICROBIOTA SHAPES THE DEVELOPMENT OF THE MUCOSAL IMMUNE SYSTEM AND MAY PROVIDE PROTECTION AGAINST IMMUNE-MEDIATED DISEASES. CELIAC DISEASE (CD) IS A CHRONIC INFLAMMATORY CONDITION TRIGGERED BY DIETARY GLUTEN PROTEINS, RECENTLY ASSOCIATED WITH GUT MICROBIOTA ALTERATIONS IN CROSS-SECTIONAL STUDIES COMPARING PATIENTS AND CONTROLS. WHETHER OR NOT THESE DIFFERENCES ARE CAUSALLY RELATED TO THE DISEASE HAS YET TO BE ELUCIDATED, BUT EVALUATION OF SPECIFIC BACTERIA ISOLATED FROM CD PATIENTS IN EXPERIMENTAL MODELS SUGGESTS THAT THEY CAN PROMOTE AN ADVERSE RESPONSE TO DIETARY GLUTEN, WHEREAS OTHER COMMENSAL BACTERIA CAN BE PROTECTIVE. GENETIC AND ENVIRONMENTAL FACTORS ASSOCIATED WITH INCREASED CD RISK HAVE ALSO BEEN LINKED TO SHIFTS IN THE GUT MICROBIOTA COMPOSITION IN INFANTS EARLY IN LIFE. EPIGENETIC MECHANISMS ALSO SEEM TO PLAY AN IMPORTANT ROLE IN MODULATING GUT MICROBIOTA COMPOSITION AND FUNCTION AND, THEORETICALLY, COULD ALSO INFLUENCE CD RISK. HERE, WE REVIEW THE CURRENT KNOWLEDGE ON HOW HOST GENETICS, ENVIRONMENTAL FACTORS, AND EPIGENETIC MODIFICATIONS COULD MODULATE GUT MICROBIOTA FUNCTIONALITY AND HOW THIS MAY INFLUENCE CD RISK. GREATER UNDERSTANDING OF THE ROLE OF THIS TRIAD IN CD ONSET AND PATHOGENESIS WILL BE VALUABLE IN DESIGNING PROOF-OF CONCEPT INTERVENTIONS IN THE GUT ECOSYSTEM, WITH A VIEW TO IMPROVING CD MANAGEMENT. 2016 12 1395 49 DIET AND MICROBIOME IN THE BEGINNING OF THE SEQUENCE OF GUT INFLAMMATION. INFLAMMATORY BOWEL DISEASE (IBD) IS A CHRONIC INFLAMMATORY CONDITION OF THE GASTROINTESTINAL TRACT DUE, AT LEAST PARTIALLY, TO AN ABERRANT AND EXCESSIVE MUCOSAL IMMUNE RESPONSE TO GUT BACTERIA IN GENETICALLY-PREDISPOSED INDIVIDUALS UNDER CERTAIN ENVIRONMENTAL FACTORS. THE INCIDENCE OF IBD IS RISING IN WESTERN AND NEWLY INDUSTRIALIZED COUNTRIES, PARALLELING THE INCREASE OF WESTERNIZED DIETARY PATTERNS, THROUGH NEW ANTIGENS, EPITHELIAL FUNCTION AND PERMEABILITY, EPIGENETIC MECHANISMS (E.G., DNA METHYLATION), AND ALTERATION OF THE GUT MICROBIOME. ALTERATION IN THE COMPOSITION AND FUNCTIONALITY OF THE GUT MICROBIOME (INCLUDING BACTERIA, VIRUSES AND FUNGI) SEEMS TO BE A NUCLEAR PATHOGENIC FACTOR. THE MICROBIOME ITSELF IS DYNAMIC, AND THE CHANGES IN FOOD QUALITY, DIETARY HABITS, LIVING CONDITIONS AND HYGIENE OF THESE WESTERN SOCIETIES, COULD INTERACT IN A COMPLEX MANNER AS MODULATORS OF DYSBIOSIS, THEREBY INFLUENCING THE ACTIVATION OF IMMUNE CELLS' PROMOTING INFLAMMATION. THE MICROBIOME PRODUCES DIVERSE SMALL MOLECULES VIA SEVERAL METABOLIC WAYS, WITH THE FIBER-DERIVED SHORT-CHAIN FATTY ACIDS (I.E., BUTYRATE) AS MAIN ELEMENTS AND HAVING ANTI-INFLAMMATORY EFFECTS. THESE METABOLITES AND SOME MICRONUTRIENTS OF THE DIET (I.E., VITAMINS, FOLIC ACID, BETA CAROTENE AND TRACE ELEMENTS) ARE REGULATORS OF INNATE AND ADAPTIVE INTESTINAL IMMUNE HOMEOSTASIS. AN EXCESSIVE AND UNHEALTHY CONSUMPTION OF SUGAR, ANIMAL FAT AND A LOW-VEGETABLE AND -FIBER DIET ARE RISK FACTORS FOR IBD APPEARANCE. FURTHERMORE, METABOLISM OF NUTRIENTS IN INTESTINAL EPITHELIUM AND IN GUT MICROBIOTA IS ALTERED BY INFLAMMATION, CHANGING THE DEMAND FOR NUTRIENTS NEEDED FOR HOMEOSTASIS. THIS ROLE OF FOOD AND A REDUCED GUT MICROBIAL DIVERSITY IN CAUSING IBD MIGHT ALSO HAVE A PROPHYLACTIC OR THERAPEUTIC ROLE FOR IBD. THE RELATIONSHIP BETWEEN DIETARY INTAKE, SYMPTOMS, AND BOWEL INFLAMMATION COULD LEAD TO DIETARY AND LIFESTYLE RECOMMENDATIONS, INCLUDING DIETS WITH ABUNDANT FRUITS, VEGETABLES, OLIVE OIL AND OILY FISH, WHICH HAVE ANTI-INFLAMMATORY EFFECTS AND COULD PREVENT DYSBIOSIS AND IBD. DIETARY MODULATION AND APPROPRIATE EXCLUSION DIETS MIGHT BE A NEW COMPLEMENTARY MANAGEMENT FOR TREATMENT AT DISEASE FLARES AND IN REFRACTORY PATIENTS, EVEN REDUCING COMPLICATIONS, HOSPITALIZATIONS AND SURGERY, THROUGH MODIFYING THE LUMINAL INTESTINAL ENVIRONMENT. 2021 13 4692 57 NEWS FROM THE "5TH INTERNATIONAL MEETING ON INFLAMMATORY BOWEL DISEASES" CAPRI 2010. AT THE "5TH INTERNATIONAL MEETING ON INFLAMMATORY BOWEL DISEASES SELECTED TOPICS OF INFLAMMATORY BOWEL DISEASE (IBD), INCLUDING THE ENVIRONMENT, GENETICS, THE GUT FLORA, THE CELL RESPONSE AND IMMUNOMODULATION WERE DISCUSSED IN ORDER TO BETTER UNDERSTAND SPECIFIC CLINICAL AND THERAPEUTIC ASPECTS. THE INCIDENCE OF IBD CONTINUES TO RISE, BOTH IN LOW AND IN HIGH-INCIDENCE AREAS. IT IS BELIEVED THAT FACTORS ASSOCIATED WITH 'WESTERNIZATION' MAY BE CONDITIONING THE EXPRESSION OF THESE DISORDERS. THE INCREASED INCIDENCE OF IBD AMONG MIGRANTS FROM LOW-INCIDENCE TO HIGH-INCIDENCE AREAS WITHIN THE SAME GENERATION SUGGESTS A STRONG ENVIRONMENTAL INFLUENCE. THE DEVELOPMENT OF GENOME-WIDE ASSOCIATION SCANNING (GWAS) TECHNOLOGIES HAS LEAD TO THE DISCOVERY OF MORE THAN 100 IBD LOCI. SOME, AS THE TH 17 PATHWAY GENES, ARE SHARED BETWEEN CROHN'S DISEASE (CD) AND ULCERATIVE COLITIS (UC), WHILE OTHER ARE IBD SUBTYPE-SPECIFIC (AUTOPHAGY GENES, EPITHELIAL BARRIER GENES). DISEASE-SPECIFIC THERAPIES TARGETING THESE PATHWAYS SHOULD BE DEVELOPED. EPIGENETIC REGULATION OF THE INFLAMMATORY RESPONSE ALSO APPEARS TO PLAY AN IMPORTANT ROLE IN THE PATHOGENESIS OF IBD. THE IMPORTANCE OF GUT FLORA IN INTESTINAL HOMEOSTASIS AND INFLAMMATION WAS REINFORCED, THE CONCEPTS OF EUBIOSIS AND DYSBIOSIS WERE INTRODUCED, AND SOME STRATEGIES FOR REVERTING DYSBIOSIS TO A HOMEOSTATIC STATE OF EUBIOSIS WERE PROPOSED. THE CURRENT STATUS OF STUDIES ON THE HUMAN GUT MICROBIOTA METAGENOME, METAPROTOME, AND METABOLOME WAS ALSO PRESENTED. THE CELL RESPONSE IN INFLAMMATION, INCLUDING ENDOPLASMIC RETICULUM (ER) STRESS RESPONSES, AUTOPHAGY AND INFLAMMASOME-DEPENDENT EVENTS WERE RELATED TO IBD PATHOGENESIS. IT WAS SUGGESTED THAT INFLAMMATION-ASSOCIATED ER STRESS RESPONSES MAY BE A COMMON TRAIT IN THE PATHOGENESIS OF VARIOUS CHRONIC IMMUNE AND METABOLIC DISEASES. HOW INNATE AND ADAPTIVE IMMUNITY SIGNALING EVENTS CAN PERPETUATE CHRONIC INFLAMMATION WAS DISCUSSED EXTENSIVELY. SIGNAL TRANSDUCTION PATHWAYS PROVIDE INTRACELLULAR MECHANISMS BY WHICH CELLS RESPOND AND ADAPT TO MULTIPLE ENVIRONMENTAL STRESSES. THE IDENTIFICATION OF THESE SIGNALS HAS LED TO A GREATER MECHANISTIC UNDERSTANDING OF IBD PATHOGENESIS AND POINTED TO POTENTIALLY NEW THERAPEUTIC TARGETS. A CRITICAL ANALYSIS OF CLINICAL TRIALS AND OF RISK-BENEFIT OF BIOLOGICAL THERAPY WAS PRESENTED. THE PROBLEM OF EPSTEIN-BARR VIRUS (EBV) AND LYMPHOMA IN IBD WAS EXTENSIVELY DISCUSSED. LYMPHOMAS CAN DEVELOP IN INTESTINAL SEGMENTS AFFECTED BY IBD AND ARE IN MOST CASES ASSOCIATED WITH EBV. THE REASONS OF TREATMENT FAILURE WERE ALSO ANALYZED BOTH FROM BASIC AND CLINICAL POINTS OF VIEW. TWO VERY INTERESTING PRESENTATIONS ON THE INTEGRATION OF RESEARCH AND CLINICAL CARE IN THE NEAR FUTURE CLOSED THE MEETING. THESE PRESENTATIONS WERE FOCUSED ON MACROTRENDS AFFECTING HEALTHCARE DELIVERY AND RESEARCH, AND THE NEED TO INNOVATE TRADITIONAL INFRASTRUCTURES TO DEAL WITH THESE CHANGING TRENDS AS WELL AS NEW OPPORTUNITIES TO ACCELERATE SCIENTIFIC KNOWLEDGE. 2010 14 2952 24 GENETIC AND EPIGENETIC ETIOLOGY OF INFLAMMATORY BOWEL DISEASE: AN UPDATE. INFLAMMATORY BOWEL DISEASE (IBD) IS A CHRONIC DISEASE WITH PERIODS OF EXACERBATION AND REMISSION OF THE DISEASE. THE ETIOLOGY OF IBD IS NOT FULLY UNDERSTOOD. MANY STUDIES POINT TO THE PRESENCE OF GENETIC, IMMUNOLOGICAL, ENVIRONMENTAL, AND MICROBIOLOGICAL FACTORS AND THE INTERACTIONS BETWEEN THEM IN THE OCCURRENCE OF IBD. THE REVIEW LOOKS AT GENETIC FACTORS IN THE CONTEXT OF BOTH IBD PREDISPOSITION AND PHARMACOGENETICS. 2022 15 3029 37 GENETICS OF INFLAMMATORY BOWEL DISEASES: A COMPARISON BETWEEN WESTERN AND EASTERN PERSPECTIVES. INFLAMMATORY BOWEL DISEASE (IBD) IS A CHRONIC RELAPSING INTESTINAL INFLAMMATORY DISORDER WITH UNIDENTIFIED CAUSES. CURRENTLY, STUDIES INDICATE THAT IBD RESULTS FROM A COMPLEX INTERPLAY BETWEEN VARIOUS GENETIC AND ENVIRONMENTAL FACTORS THAT PRODUCE INTESTINAL INFLAMMATION. HOWEVER, THESE FACTORS MAY DIFFER FOR ASIANS AND CAUCASIANS. THUS, DIFFERENCES IN EPIDEMIOLOGY, GENETIC VARIANTS, AND CLINICAL PHENOTYPES OF IBD HAVE BEEN OBSERVED BETWEEN THE TWO POPULATIONS. UNDERSTANDING THE DISCREPANCIES BETWEEN DATA FROM POPULATIONS WITH DIFFERENT GENETIC BACKGROUNDS AND ENVIRONMENTAL FACTORS MAY REVEAL FUNDAMENTAL ASPECTS OF IBD PATHOGENESIS. ACCORDINGLY, THIS REVIEW WILL SUMMARIZE THE CURRENT KNOWLEDGE OF IBD GENETICS STUDIED IN ASIAN COUNTRIES AND COMPARE IT WITH THAT FROM WESTERN COUNTRIES, WITH SPECIAL FOCUS ON INNATE BACTERIAL SENSING, AUTOPHAGY, AND THE INTERLEUKIN-23 RECEPTOR-T HELPER CELL 17 PATHWAY. THE EPIGENETIC NATURE OF IBD PATHOGENESIS AS WELL AS THE PHARMACOGENETICS RELATED TO THE USE OF IMMUNOMODULATORS WILL ALSO BE BRIEFLY COVERED. 2013 16 5558 43 ROLE OF GUT MICROBIOTA IN THE AETIOLOGY OF OBESITY: PROPOSED MECHANISMS AND REVIEW OF THE LITERATURE. THE AETIOLOGY OF OBESITY HAS BEEN ATTRIBUTED TO SEVERAL FACTORS (ENVIRONMENTAL, DIETARY, LIFESTYLE, HOST, AND GENETIC FACTORS); HOWEVER NONE OF THESE FULLY EXPLAIN THE INCREASE IN THE PREVALENCE OF OBESITY WORLDWIDE. GUT MICROBIOTA LOCATED AT THE INTERFACE OF HOST AND ENVIRONMENT IN THE GUT ARE A NEW AREA OF RESEARCH BEING EXPLORED TO EXPLAIN THE EXCESS ACCUMULATION OF ENERGY IN OBESE INDIVIDUALS AND MAY BE A POTENTIAL TARGET FOR THERAPEUTIC MANIPULATION TO REDUCE HOST ENERGY STORAGE. SEVERAL MECHANISMS HAVE BEEN SUGGESTED TO EXPLAIN THE ROLE OF GUT MICROBIOTA IN THE AETIOLOGY OF OBESITY SUCH AS SHORT CHAIN FATTY ACID PRODUCTION, STIMULATION OF HORMONES, CHRONIC LOW-GRADE INFLAMMATION, LIPOPROTEIN AND BILE ACID METABOLISM, AND INCREASED ENDOCANNABINOID RECEPTOR SYSTEM TONE. HOWEVER, EVIDENCE FROM ANIMAL AND HUMAN STUDIES CLEARLY INDICATES CONTROVERSIES IN DETERMINING THE CAUSE OR EFFECT RELATIONSHIP BETWEEN THE GUT MICROBIOTA AND OBESITY. METAGENOMICS BASED STUDIES INDICATE THAT FUNCTIONALITY RATHER THAN THE COMPOSITION OF GUT MICROBIOTA MAY BE IMPORTANT. FURTHER MECHANISTIC STUDIES CONTROLLING FOR ENVIRONMENTAL AND EPIGENETIC FACTORS ARE THEREFORE REQUIRED TO HELP UNRAVEL OBESITY PATHOGENESIS. 2016 17 4365 35 MIRNA MOLECULES-LATE BREAKING TREATMENT FOR INFLAMMATORY BOWEL DISEASES? MICRORNAS (MIRNAS) ARE A GROUP OF NON-CODING RNAS THAT PLAY A CRITICAL ROLE IN REGULATING EPIGENETIC MECHANISMS IN INFLAMMATION-RELATED DISEASES. INFLAMMATORY BOWEL DISEASES (IBDS), WHICH PRIMARILY INCLUDE ULCERATIVE COLITIS (UC) AND CROHN'S DISEASE (CD), ARE CHARACTERIZED BY CHRONIC RECURRENT INFLAMMATION OF INTESTINAL TISSUES. DUE TO THE MULTIFACTORIAL ETIOLOGY OF THESE DISEASES, THE DEVELOPMENT OF INNOVATIVE TREATMENT STRATEGIES THAT CAN EFFECTIVELY MAINTAIN REMISSION AND ALLEVIATE DISEASE SYMPTOMS IS A MAJOR CHALLENGE. IN RECENT YEARS, EVIDENCE FOR THE REGULATORY ROLE OF MIRNAS IN THE PATHOGENETIC MECHANISMS OF VARIOUS DISEASES, INCLUDING IBD, HAS BEEN ACCUMULATING. IN LIGHT OF THESE FINDINGS, MIRNAS REPRESENT POTENTIAL INNOVATIVE CANDIDATES FOR THERAPEUTIC APPLICATION IN IBD. IN THIS REVIEW, WE DISCUSS RECENT FINDINGS ON THE ROLE OF MIRNAS IN REGULATING INFLAMMATORY RESPONSES, MAINTAINING INTESTINAL BARRIER INTEGRITY, AND DEVELOPING FIBROSIS IN CLINICAL AND EXPERIMENTAL IBD. THE FOCUS IS ON THE EXISTING LITERATURE, INDICATING POTENTIAL THERAPEUTIC APPLICATION OF MIRNAS IN BOTH PRECLINICAL EXPERIMENTAL IBD MODELS AND TRANSLATIONAL DATA IN THE CONTEXT OF CLINICAL IBD. TO DATE, A LARGE AND DIVERSE DATA SET, WHICH IS GROWING RAPIDLY, SUPPORTS THE POTENTIAL USE OF MIRNA-BASED THERAPIES IN CLINICAL PRACTICE, ALTHOUGH MANY QUESTIONS REMAIN UNANSWERED. 2023 18 1168 48 CONTRIBUTION OF EPITHELIAL AND GUT MICROBIOME INFLAMMATORY BIOMARKERS TO THE IMPROVEMENT OF COLORECTAL CANCER PATIENTS' STRATIFICATION. IN ORDER TO ENSURE THAT PRIMARY ENDPOINTS OF CLINICAL STUDIES ARE ATTAINED, THE PATIENTS' STRATIFICATION IS AN IMPORTANT ASPECT. SELECTION CRITERIA INCLUDE AGE, GENDER, AND ALSO SPECIFIC BIOMARKERS, SUCH AS INFLAMMATION SCORES. THESE CRITERIA ARE NOT SUFFICIENT TO ACHIEVE A STRAIGHTFORWARD SELECTION, HOWEVER, IN CASE OF MULTIFACTORIAL DISEASES, WITH UNKNOWN OR PARTIALLY IDENTIFIED MECHANISMS, OCCASIONALLY INCLUDING HOST FACTORS, AND THE MICROBIOME. IN THESE CASES, THE EFFICACY OF INTERVENTIONS IS DIFFICULT TO PREDICT, AND AS A RESULT, THE SELECTION OF SUBJECTS IS OFTEN RANDOM. COLORECTAL CANCER (CRC) IS A HIGHLY HETEROGENEOUS DISEASE, WITH VARIABLE CLINICAL FEATURES, OUTCOMES, AND RESPONSE TO THERAPY; THE CRC ONSET AND PROGRESS INVOLVES MULTIPLE SEQUENTIAL STEPS WITH ACCUMULATION OF GENETIC ALTERATIONS, NAMELY, MUTATIONS, GENE AMPLIFICATION, AND EPIGENETIC CHANGES. THE GUT MICROBES, EITHER EUBIOTIC OR DYSBIOTIC, COULD INFLUENCE THE CRC EVOLUTION THROUGH A COMPLEX AND VERSATILE CROSSTALK WITH THE INTESTINAL AND IMMUNE CELLS, PERMANENTLY CHANGING THE TUMOR MICROENVIRONMENT. THERE HAVE BEEN SIGNIFICANT ADVANCES IN THE DEVELOPMENT OF PERSONALIZED APPROACHES FOR CRC SCREENING, TREATMENT, AND POTENTIAL PREVENTION. ADVANCES IN MOLECULAR TECHNIQUES BRING NEW CRITERIA FOR PATIENTS' STRATIFICATION-MUTATIONAL ANALYSIS AT THE TIME OF DIAGNOSIS TO GUIDE TREATMENT, FOR EXAMPLE. GUT MICROBIOME HAS EMERGED AS THE MAIN TRIGGER OF GUT MUCOSAL HOMEOSTASIS. THIS MAY IMPACT CANCER SUSCEPTIBILITY THROUGH MAINTENANCE OF THE EPITHELIAL/MUCUS BARRIER AND PRODUCTION OF PROTECTIVE METABOLITES, SUCH AS SHORT-CHAIN FATTY ACIDS (SCFAS) VIA INTERACTIONS WITH THE HOSTS' DIET AND METABOLISM. MICROBIOME DYSBIOSIS LEADS TO THE ENRICHMENT OF CANCER-PROMOTING BACTERIAL POPULATIONS, LOSS OF PROTECTIVE POPULATIONS OR MAINTAINING AN INFLAMMATORY CHRONIC STATE, ALL OF WHICH CONTRIBUTE TO THE DEVELOPMENT AND PROGRESSION OF CRC. MEANWHILE, VARIATIONS IN PATIENT RESPONSES TO ANTI-CANCER IMMUNO- AND CHEMOTHERAPIES WERE ALSO LINKED TO INTER-INDIVIDUAL DIFFERENCES IN INTESTINE MICROBIOMES. THE AUTHORS AIM TO HIGHLIGHT THE CONTRIBUTION OF EPITHELIAL AND GUT MICROBIOME INFLAMMATORY BIOMARKERS IN THE IMPROVEMENT OF CRC PATIENTS' STRATIFICATION TOWARDS A PERSONALIZED APPROACH OF EARLY DIAGNOSIS AND TREATMENT. 2021 19 3017 34 GENETICS AND EPIGENETICS OF INFLAMMATORY BOWEL DISEASE. THE RELEVANCE OF GENETIC AND EPIGENETIC ALTERATIONS IN THE PATHOGENESIS OF INFLAMMATORY BOWEL DISEASE (IBD) IS STILL POORLY UNDERSTOOD. SO FAR, 240 RISK GENE LOCI HAVE BEEN ASSOCIATED WITH IBD. THEY ARE MAINLY INVOLVED IN REGULATING INNATE AND ADAPTIVE IMMUNITY, AS WELL AS MAINTAINING INTESTINAL EPITHELIAL BARRIER FUNCTION. HOWEVER, THE FUNCTIONAL CONSEQUENCES OF THE IDENTIFIED GENETIC POLYMORPHISMS FOR IBD PATHOGENESIS IN VIVO ARE OFTEN UNKNOWN. EVEN LESS IS KNOWN ABOUT THE ROLE FOR EPIGENETIC MODIFICATIONS IN IBD PATHOGENESIS. THOUGH A NUMBER OF EPIGENETIC EVENTS SEEM TO BE CAUSATIVELY INVOLVED IBD PATHOGENESIS, OUR KNOWLEDGE ABOUT THE FUNCTIONAL RELEVANCE OF THOSE EPIGENETIC MODIFICATIONS IS SCANTY. THIS OPENS UP A BROAD RESEARCH FIELD THAT GENERATES NOVEL INSIGHTS INTO THE PATHOPHYSIOLOGY OF INTESTINAL AND CHRONIC INFLAMMATORY DISEASE. PATTERNS OF DNA METHYLATION AND HISTONE MODIFICATIONS MIGHT SERVE NOT ONLY AS BIOMARKERS OF DISEASE ACTIVITY OR DISEASE COURSE, BUT ALSO AS NEW TARGETS IN THERAPEUTIC INTERVENTIONS IN IBD PATIENTS. 2018 20 2617 43 EPIGENOME TARGETING BY PROBIOTIC METABOLITES. BACKGROUND: THE INTESTINAL MICROBIOTA PLAYS AN IMPORTANT ROLE IN IMMUNE DEVELOPMENT AND HOMEOSTASIS. A DISTURBED MICROBIOTA DURING EARLY INFANCY IS ASSOCIATED WITH AN INCREASED RISK OF DEVELOPING INFLAMMATORY AND ALLERGIC DISEASES LATER IN LIFE. THE MECHANISMS UNDERLYING THESE EFFECTS ARE POORLY UNDERSTOOD BUT ARE LIKELY TO INVOLVE ALTERATIONS IN MICROBIAL PRODUCTION OF FERMENTATION-DERIVED METABOLITES, WHICH HAVE POTENT IMMUNE MODULATING PROPERTIES AND ARE REQUIRED FOR MAINTENANCE OF HEALTHY MUCOSAL IMMUNE RESPONSES. PROBIOTICS ARE BENEFICIAL BACTERIA THAT HAVE THE CAPACITY TO ALTER THE COMPOSITION OF BACTERIAL SPECIES IN THE INTESTINE THAT CAN IN TURN INFLUENCE THE PRODUCTION OF FERMENTATION-DERIVED METABOLITES. PRINCIPAL AMONG THESE METABOLITES ARE THE SHORT-CHAIN FATTY ACIDS BUTYRATE AND ACETATE THAT HAVE POTENT ANTI-INFLAMMATORY ACTIVITIES IMPORTANT IN REGULATING IMMUNE FUNCTION AT THE INTESTINAL MUCOSAL SURFACE. THEREFORE STRATEGIES AIMED AT RESTORING THE MICROBIOTA PROFILE MAY BE EFFECTIVE IN THE PREVENTION OR TREATMENT OF ALLERGIC AND INFLAMMATORY DISEASES. PRESENTATION OF THE HYPOTHESIS: PROBIOTIC BACTERIA HAVE DIVERSE EFFECTS INCLUDING ALTERING MICROBIOTA COMPOSITION, REGULATING EPITHELIAL CELL BARRIER FUNCTION AND MODULATING OF IMMUNE RESPONSES. THE PRECISE MOLECULAR MECHANISMS MEDIATING THESE PROBIOTIC EFFECTS ARE NOT WELL UNDERSTOOD. SHORT-CHAIN FATTY ACIDS SUCH AS BUTYRATE ARE A CLASS OF HISTONE DEACETYLASE INHIBITORS IMPORTANT IN THE EPIGENETIC CONTROL OF HOST CELL RESPONSES. IT IS HYPOTHESIZED THAT THE BIOLOGICAL FUNCTION OF PROBIOTICS MAY BE A RESULT OF EPIGENETIC MODIFICATIONS THAT MAY EXPLAIN THE WIDE RANGE OF EFFECTS OBSERVED. STUDIES DELINEATING THE EFFECTS OF PROBIOTICS ON SHORT-CHAIN FATTY ACID PRODUCTION AND THE EPIGENETIC ACTIONS OF SHORT-CHAIN FATTY ACIDS WILL ASSIST IN UNDERSTANDING THE ASSOCIATION BETWEEN MICROBIOTA AND ALLERGIC OR AUTOIMMUNE DISORDERS. TESTING THE HYPOTHESIS: WE PROPOSE THAT TREATMENT WITH SPECIFIC PROBIOTIC BACTERIA UNDER IN VIVO CONDITIONS WOULD OFFER THE IDEAL CONDITIONS TO EXAMINE THE MICROBIOLOGICAL, IMMUNOLOGICAL AND EPIGENETIC MECHANISMS OF ACTION. ADVANCES IN EPIGENETIC TECHNOLOGY NOW ALLOW INVESTIGATORS TO BETTER UNDERSTAND THE COMPLEX BIOLOGICAL PROPERTIES OF PROBIOTICS AND THEIR METABOLITES. IMPLICATIONS OF THE HYPOTHESIS: DETERMINING THE PRECISE MECHANISMS OF PROBIOTIC ACTION WILL LEAD TO MORE SPECIFIC AND EFFICACIOUS THERAPEUTIC STRATEGIES IN THE PREVENTION OR TREATMENT OF CHRONIC INFLAMMATORY CONDITIONS. 2010