1 3106 133 GENOMICS AND THE RESPIRATORY EFFECTS OF AIR POLLUTION EXPOSURE. ADVERSE HEALTH EFFECTS FROM AIR POLLUTANTS REMAIN IMPORTANT, DESPITE IMPROVEMENT IN AIR QUALITY IN THE PAST FEW DECADES. THE EXACT MECHANISMS OF LUNG INJURY FROM EXPOSURE TO AIR POLLUTANTS ARE NOT YET FULLY UNDERSTOOD. STUDYING THE GENOME (E.G. SINGLE-NUCLEOTIDE POLYMORPHISMS (SNP) ), EPIGENOME (E.G. METHYLATION OF GENES), TRANSCRIPTOME (MRNA EXPRESSION) AND MICRORNAOME (MICRORNA EXPRESSION) HAS THE POTENTIAL TO IMPROVE OUR UNDERSTANDING OF THE ADVERSE EFFECTS OF AIR POLLUTANTS. GENOME-WIDE ASSOCIATION STUDIES OF SNP HAVE DETECTED SNP ASSOCIATED WITH RESPIRATORY PHENOTYPES; HOWEVER, TO DATE, ONLY CANDIDATE GENE STUDIES OF AIR POLLUTION EXPOSURE HAVE BEEN PERFORMED. CHANGES IN EPIGENETIC PROCESSES, SUCH DNA METHYLATION THAT LEADS TO GENE SILENCING WITHOUT ALTERING THE DNA SEQUENCE, OCCUR WITH AIR POLLUTANT EXPOSURE, ESPECIALLY GLOBAL AND GENE-SPECIFIC METHYLATION CHANGES. RESPIRATORY CELL LINE AND ANIMAL MODELS DEMONSTRATE DISTINCT GENE EXPRESSION SIGNATURES IN THE TRANSCRIPTOME, ARISING FROM EXPOSURE TO PARTICULATE MATTER OR OZONE. PARTICULATE MATTER AND OTHER ENVIRONMENTAL TOXINS ALTER EXPRESSION OF MICRORNA, WHICH ARE SHORT NON-CODING RNA THAT REGULATE GENE EXPRESSION. WHILE IT IS CLEARLY IMPORTANT TO CONTAIN RISING LEVELS OF AIR POLLUTION, STRATEGIES ALSO NEED TO BE DEVELOPED TO MINIMIZE THE DAMAGING EFFECTS OF AIR POLLUTANT EXPOSURE ON THE LUNG, ESPECIALLY FOR PATIENTS WITH CHRONIC LUNG DISEASE AND FOR PEOPLE AT RISK OF FUTURE LUNG DISEASE. CAREFUL STUDY OF GENOMIC RESPONSES WILL IMPROVE OUR UNDERSTANDING OF MECHANISMS OF LUNG INJURY FROM AIR POLLUTION AND ENABLE FUTURE CLINICAL TESTING OF INTERVENTIONS AGAINST THE TOXIC EFFECTS OF AIR POLLUTANTS. 2012 2 1324 37 DEOXYRIBONUCLEIC ACID (DNA) METHYLATION IN CHILDREN EXPOSED TO AIR POLLUTION: A POSSIBLE MECHANISM UNDERLYING RESPIRATORY HEALTH EFFECTS DEVELOPMENT. AIR POLLUTION IS A SUBSTANTIAL ENVIRONMENTAL THREAT TO CHILDREN AND ACTS AS ACUTE AND CHRONIC DISEASE RISK FACTORS ALIKE. SEVERAL STUDIES HAVE PREVIOUSLY EVALUATED EPIGENETIC MODIFICATIONS CONCERNING ITS EXPOSURE ACROSS VARIOUS LIFE STAGES. HOWEVER, FINDINGS ON EPIGENETIC MODIFICATIONS AS THE CONSEQUENCES OF AIR POLLUTION DURING CHILDHOOD ARE RATHER MINIMAL. THIS REVIEW EVALUATED HIGHLY RELEVANT STUDIES IN THE FIELD TO ANALYZE THE EXISTING LITERATURE REGARDING EXPOSURE TO AIR POLLUTION, WITH A FOCUS ON EPIGENETIC ALTERATIONS DURING CHILDHOOD AND THEIR CONNECTIONS WITH RESPIRATORY HEALTH EFFECTS. THE SEARCH WAS CONDUCTED USING READILY AVAILABLE ELECTRONIC DATABASES (PUBMED AND SCIENCEDIRECT) TO SCREEN FOR CHILDREN'S STUDIES ON EPIGENETIC MECHANISMS FOLLOWING EITHER PRE- OR POST-NATAL EXPOSURE TO AIR POLLUTANTS. STUDIES RELEVANT ENOUGH AND MATCHED THE PREDETERMINED CRITERIA WERE CHOSEN TO BE REVIEWED. NON-ENGLISH ARTICLES AND STUDIES THAT DID NOT REPORT BOTH AIR MONITORING AND EPIGENETIC OUTCOMES IN THE SAME ARTICLE WERE EXCLUDED. THE REVIEW FOUND THAT EPIGENETIC CHANGES HAVE BEEN LINKED WITH EXPOSURE TO AIR POLLUTANTS DURING EARLY LIFE WITH EVIDENCE AND REPORTS OF HOW THEY MAY DEREGULATE THE EPIGENOME BALANCE, THUS INDUCING DISEASE PROGRESSION IN THE FUTURE. EPIGENETIC STUDIES EVOLVE AS A PROMISING NEW APPROACH IN DECIPHERING THE UNDERLYING IMPACTS OF AIR POLLUTION ON DEOXYRIBONUCLEIC ACID (DNA) DUE TO LINKS ESTABLISHED BETWEEN SOME OF THESE EPIGENETIC MECHANISMS AND ILLNESSES. 2021 3 396 44 AN UPDATE ON EPIGENETICS AND CHILDHOOD RESPIRATORY DISEASES. EPIGENETIC MECHANISMS, DEFINED AS CHANGES IN PHENOTYPE OR GENE EXPRESSION CAUSED BY MECHANISMS OTHER THAN CHANGES IN THE UNDERLYING DNA SEQUENCE, HAVE BEEN PROPOSED TO CONSTITUTE A LINK BETWEEN GENETIC AND ENVIRONMENTAL FACTORS THAT AFFECT COMPLEX DISEASES. RECENT STUDIES SHOW THAT DNA METHYLATION, ONE OF THE KEY EPIGENETIC MECHANISMS, IS ALTERED IN CHILDREN EXPOSED TO AIR POLLUTANTS AND ENVIRONMENTAL TOBACCO SMOKE EARLY IN LIFE. SEVERAL CANDIDATE GENE STUDIES ON EPIGENETICS HAVE BEEN PUBLISHED TO DATE, BUT IT IS ONLY RECENTLY THAT GLOBAL METHYLATION ANALYSES HAVE BEEN PERFORMED FOR RESPIRATORY DISORDERS SUCH AS ASTHMA AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE. HOWEVER, LARGE-SCALE STUDIES WITH ADEQUATE POWER ARE YET TO BE PRESENTED IN CHILDREN, AND IMPLICATIONS FOR CLINICAL USE REMAIN TO BE EVALUATED. IN THIS REVIEW, WE SUMMARIZE THE RECENT ADVANCES IN EPIGENETICS AND RESPIRATORY DISORDERS IN CHILDREN, WITH A MAIN FOCUS ON METHODOLOGICAL CHALLENGES AND ANALYSES RELATED TO PHENOTYPE AND EXPOSURE USING GLOBAL METHYLATION APPROACHES. 2014 4 4266 37 MICRO-RNAS: CROSSROADS BETWEEN THE EXPOSURE TO ENVIRONMENTAL PARTICULATE POLLUTION AND THE OBSTRUCTIVE PULMONARY DISEASE. ENVIRONMENTAL POLLUTION HAS REACHED A GLOBAL ECHO AND REPRESENTS A SERIOUS PROBLEM FOR HUMAN HEALTH. AIR POLLUTION ENCOMPASSES A SET OF HAZARDOUS SUBSTANCES, SUCH AS PARTICULATE MATTER AND HEAVY METALS (E.G., CADMIUM, LEAD, AND ARSENIC), AND HAS A STRONG IMPACT ON THE ENVIRONMENT BY AFFECTING GROUNDWATER, SOIL, AND AIR. AN ADAPTIVE RESPONSE TO ENVIRONMENTAL CUES IS ESSENTIAL FOR HUMAN SURVIVAL, WHICH IS ASSOCIATED WITH THE INDUCTION OF ADAPTIVE PHENOTYPES. THE EPIGENETIC MECHANISMS REGULATING THE EXPRESSION PATTERNS OF SEVERAL GENES ARE PROMISING CANDIDATES TO PROVIDE MECHANISTIC AND PROGNOSTIC INSIGHTS INTO THIS. MICRO-RNAS (MIRNAS) FULFIL THESE FEATURES GIVEN THEIR ABILITY TO RESPOND TO ENVIRONMENTAL FACTORS AND THEIR CRITICAL ROLE IN DETERMINING PHENOTYPES. THESE MOLECULES ARE PRESENT IN EXTRACELLULAR FLUIDS, AND THEIR EXPRESSION PATTERNS ARE ORGAN-, TISSUE-, OR CELL-SPECIFIC. MOREOVER, THE EXPERIMENTAL SETTINGS FOR THEIR QUANTITATIVE AND QUALITATIVE ANALYSIS ARE ROBUST, STANDARDIZED, AND INEXPENSIVE. IN THIS REVIEW, WE PROVIDE AN UPDATE ON THE ROLE OF MIRNAS AS SUITABLE TOOLS FOR UNDERSTANDING THE MECHANISMS BEHIND THE PHYSIOPATHOLOGICAL RESPONSE TO TOXICANTS AND THE PROGNOSTIC VALUE OF THEIR EXPRESSION PATTERN ASSOCIABLE WITH SPECIFIC EXPOSURES. WE LOOK AT THE MECHANISTIC EVIDENCE ASSOCIABLE TO THE ROLE OF MIRNAS IN THE PROCESSES LEADING TO ENVIRONMENTAL-INDUCED PULMONARY DISEASE (I.E., CHRONIC OBSTRUCTIVE PULMONARY DISEASE). 2020 5 6781 45 [BREATHING: AMBIENT AIR POLLUTION AND HEALTH - PART III]. THE THIRD PART OF THE DGP STATEMENT INTRODUCES THE CURRENT BODY OF KNOWLEDGE ON LESS STUDIED HEALTH OUTCOMES ASSOCIATED WITH EXPOSURE TO AMBIENT AIR POLLUTION: THE NEGATIVE IMPACT ON METABOLISM LEADING TO IMPAIRED GLUCOSE TOLERANCE AND DIABETES AS WELL AS CONTRIBUTION TO THE DEVELOPMENT OF NEURODEGENERATIVE DISORDERS AND DELAYED COGNITIVE FUNCTION IN CHILDREN. FURTHERMORE, PRENATAL EXPOSURE AND ADVERSE EFFECTS ON MOTHER AND CHILD ARE ADDRESSED. FINALLY, THE CURRENTLY DISCUSSED BIOLOGICAL MECHANISMS UNDERLYING VARIOUS HEALTH EFFECTS ASSOCIATED WITH EXPOSURE TO AIR POLLUTION ARE DESCRIBED.DIFFERING, BUT OFTEN COMPLEMENTARY BIOLOGICAL MECHANISMS CREATE THE BASIS FOR THE DIVERSE HEALTH OUTCOMES CAUSED BY AIR POLLUTION. OXIDATIVE STRESS AND A SUBCLINICAL INFLAMMATORY RESPONSE IN THE LUNGS AND ON A SYSTEMIC LEVEL ("LOW-GRADE SYSTEMIC INFLAMMATION") ARE CONSIDERED TO BE KEY MECHANISMS. THEY PROMOTE SECONDARY ALTERATIONS IN THE BODY, SUCH AS VASCULAR OR METABOLIC PROCESSES, AND MAY ALSO RESULT IN THE CURRENTLY STUDIED EPIGENETIC PHENOMENA OR NEUROINFLAMMATION. IN THIS CONTEXT, THE HEALTH SIGNIFICANCE OF SOLUBLE PARTICULATE MATTER AND THE ROLE OF ULTRAFINE PARTICLES TRANSLOCATED ACROSS BIOLOGICAL MEMBRANES INTO BLOOD VESSEL AND TRANSPORTED VIA THE CIRCULATION TO SECONDARY TARGET ORGANS, SUCH AS LIVER, BRAIN OR THE FETUS, ARE INTENSIVELY DISCUSSED.DIABETES IS ONE OF THE LEADING CHRONIC DISEASES WORLDWIDE, WITH A PREVALENCE OF ALMOST 14 % IN GERMANY. ALTHOUGH LIFESTYLE FACTORS ARE THE MAIN CAUSES, CURRENT EVIDENCE SUGGESTS THAT LONG-TERM EXPOSURE TO AIR POLLUTION MAY ADDITIONALLY INCREASE THE RISK FOR TYPE 2 DIABETES. SUPPORTING EVIDENCE FOR A CAUSAL ROLE OF AIR POLLUTION IS PROVIDED BY STUDIES ADDRESSING THE REGULATION OF THE BLOOD GLUCOSE LEVELS IN METABOLICALLY HEALTHY PARTICIPANTS, INSULIN SENSITIVITY, OR PREGNANCY-RELATED DIABETES. EXPERIMENTAL STUDIES PROVIDE FURTHER SUPPORT FOR PLAUSIBLE BIOLOGICAL MECHANISMS. HOWEVER, PROSPECTIVE STUDIES ARE NEEDED TO GAIN MORE EVIDENCE, TAKING MULTIPLE LIFESTYLE AND ENVIRONMENTAL FACTORS, SUCH AS GREEN SPACE AND NOISE, AND AN IMPROVED INDIVIDUAL EXPOSURE ASSESSMENT INTO ACCOUNT.THE AGING POPULATION HAS AN INCREASED RISK OF NEURODEGENERATIVE DISEASES. FIRST STUDIES POINT TOWARDS A CONTRIBUTION OF CHRONIC EXPOSURE TO AIR POLLUTION, SPECIFICALLY BY PARTICULATE MATTER. SEVERAL STUDIES REPORT ITS ASSOCIATION WITH DECREASED NEUROCOGNITIVE CAPACITY OR AN INCREASED PREVALENCE OF DEMENTIA OR ALZHEIMER'S DISEASE IN ADULTS. HOWEVER, THE STUDIES ARE INHOMOGENEOUS REGARDING DESIGN, EXPOSURE AND OUTCOME, LEADING TO INCONSISTENT RESULTS. WITH RESPECT TO THE INFLUENCE ON NEUROCOGNITIVE DEVELOPMENT OF CHILDREN, FIRST STUDIES SUGGEST AN ASSOCIATION BETWEEN THE LEVEL OF AIR POLLUTION, E. G. AT SCHOOL, AND DELAYED COGNITIVE DEVELOPMENT.EVEN THOUGH THE EVIDENCE FOR THE DIFFERENT BIOLOGICAL ENDPOINTS DURING PREGNANCY IS STILL HETEROGENEOUS, THE STUDIES GENERALLY POINT TOWARDS AN ADVERSE IMPACT OF AIR POLLUTION ON THE MATERNAL AND FETAL ORGANISMS. THE STRONGEST EVIDENCE EXISTS FOR LOW BIRTH WEIGHT, WITH SMALL EFFECT SIZES OF ONLY SOME GRAMS, AND FOR A HIGHER INCIDENCE OF REDUCED BIRTH WEIGHT (< 2500 G). AN INCREASED RISK FOR GESTATIONAL HYPERTENSION AND PREECLAMPSIA UNDERSCORES THE POSSIBLE IMPACT OF EXPOSURE TO AIR POLLUTION ON THE MATERNAL ORGANISM. HOWEVER, THE CURRENT BODY OF EVIDENCE DOES NOT YET ALLOW A FINAL CONCLUSION ON THE INFLUENCE OF INTRAUTERINE EXPOSURE TO AIR POLLUTION REGARDING EARLY CHILDHOOD LUNG FUNCTION AND DEVELOPMENT OF ALLERGIES, PARTICULARLY IN LIGHT OF THE FACT THAT IT IS HARD TO DISTINGUISH IN EPIDEMIOLOGICAL STUDIES BETWEEN THE EFFECTS OF PRE- AND POSTNATAL EXPOSURE. 2019 6 5434 29 RELATIONSHIP BETWEEN ENVIRONMENTAL EXPOSURES IN CHILDREN AND ADULT LUNG DISEASE: THE CASE FOR OUTDOOR EXPOSURES. THERE IS A GROWING UNDERSTANDING THAT CHRONIC RESPIRATORY DISEASES IN ADULTS HAVE THEIR ORIGINS IN EARLY LIFE. ADVERSE ENVIRONMENTAL EXPOSURES OCCURRING IN VULNERABLE PERIODS DURING LUNG GROWTH AND DEVELOPMENT IN THE FETAL PERIOD AND IN EARLY CHILDHOOD THAT ALTER LUNG STRUCTURE AND LIMIT THE GROWTH IN LUNG FUNCTION MAY HAVE LIFELONG CONSEQUENCES. EVIDENCE IS INCREASING THAT EXPOSURE TO THE AMBIENT ENVIRONMENT, INCLUDING AIR POLLUTANTS, PERSISTENT TOXIC SUBSTANCES, WATER POLLUTANTS AND RESPIRATORY VIRAL INFECTIONS, CAN INHIBIT LUNG FUNCTION GROWTH AND PREDISPOSE TO CHRONIC NON-MALIGNANT LUNG DISEASES. THESE EXPOSURES GENERALLY INTERACT WITH A GENETIC PREDISPOSITION, AND GENE-ENVIRONMENT INTERACTIONS AND EPIGENETIC PHENOMENA ARE ATTRACTING CONSIDERABLE STUDY. AN UNDERSTANDING OF HOW AMBIENT EXPOSURES IMPACT ON NORMAL LUNG GROWTH AND DEVELOPMENT WILL AID IN UNDERSTANDING OF HOW CHRONIC RESPIRATORY DISEASES OF ADULTS DEVELOP AND MAY LEAD TO NEW PREVENTATIVE STRATEGIES. 2010 7 4317 35 MICRORNAS AS REGULATORS OF AIRBORNE POLLUTION-INDUCED LUNG INFLAMMATION AND CARCINOGENESIS. THE INCREASING INCIDENCE OF PULMONARY INFLAMMATION AND LUNG CANCER, AS WELL AS EXACERBATION OF PRE-EXISTING CHRONIC LUNG DISEASES BY EXPOSURE TO AIRBORNE POLLUTANTS, E.G., PARTICULATE MATTER AND CIGARETTE SMOKE, IS BECOMING A MAJOR PUBLIC HEALTH CONCERN IN THE WORLD. HOWEVER, THE EXACT MECHANISMS OF PULMONARY INJURY FROM EXPOSURE TO THESE AIRBORNE INSULTS HAVE NOT BEEN FULLY ELUCIDATED. NEVERTHELESS, ACCUMULATING EVIDENCE SUGGESTS THAT MICRORNAS (MIRNAS) MAY PLAY A UNIQUE ROLE IN THE REGULATION OF AIRBORNE AGENT-INDUCED LUNG INFLAMMATION AND CARCINOGENESIS. SINCE EPIGENETIC MODIFICATIONS ARE HERITABLE AND REVERSIBLE, THIS MAY PROVIDE A NEW INSIGHT INTO THE RELATIONSHIP OF MIRNAS AND ENVIRONMENTAL POLLUTION-RELATED LUNG DISORDERS. THE AIM OF THIS REVIEW WAS TO UPDATE OUR EXISTING KNOWLEDGE REGARDING THE MECHANISMS BY WHICH AIRBORNE POLLUTANTS ALTERING MIRNA PROFILES IN THE LUNG, SPECIFICALLY FOR CIGARETTE SMOKE AND AIRBORNE PARTICULATE MATTER, AND THE POTENTIAL BIOLOGICAL ROLES OF MIRNAS IN THE INITIATION OF PULMONARY INFLAMMATION AND LUNG CANCER, AS WELL AS THE REGULATION OF UNDERLYING GENETIC SUSCEPTIBILITY TO THESE ENVIRONMENTAL STRESSORS. 2015 8 1014 33 CIGARETTE SMOKING AND DNA METHYLATION. DNA METHYLATION IS THE MOST STUDIED EPIGENETIC MODIFICATION, CAPABLE OF CONTROLLING GENE EXPRESSION IN THE CONTEXTS OF NORMAL TRAITS OR DISEASES. IT IS HIGHLY DYNAMIC DURING EARLY EMBRYOGENESIS AND REMAINS RELATIVELY STABLE THROUGHOUT LIFE, AND SUCH PATTERNS ARE INTRICATELY RELATED TO HUMAN DEVELOPMENT. DNA METHYLATION IS A QUANTITATIVE TRAIT DETERMINED BY A COMPLEX INTERPLAY OF GENETIC AND ENVIRONMENTAL FACTORS. GENETIC VARIANTS AT A SPECIFIC LOCUS CAN INFLUENCE BOTH REGIONAL AND DISTANT DNA METHYLATION. THE ENVIRONMENT CAN HAVE VARYING EFFECTS ON DNA METHYLATION DEPENDING ON WHEN THE EXPOSURE OCCURS, SUCH AS DURING PRENATAL LIFE OR DURING ADULTHOOD. IN PARTICULAR, CIGARETTE SMOKING IN THE CONTEXT OF BOTH CURRENT SMOKING AND PRENATAL EXPOSURE IS A STRONG MODIFIER OF DNA METHYLATION. EPIGENOME-WIDE ASSOCIATION STUDIES HAVE UNCOVERED CANDIDATE GENES ASSOCIATED WITH CIGARETTE SMOKING THAT HAVE BIOLOGICALLY RELEVANT FUNCTIONS IN THE ETIOLOGY OF SMOKING-RELATED DISEASES. AS SUCH, DNA METHYLATION IS A POTENTIAL MECHANISTIC LINK BETWEEN CURRENT SMOKING AND CANCER, AS WELL AS PRENATAL CIGARETTE-SMOKE EXPOSURE AND THE DEVELOPMENT OF ADULT CHRONIC DISEASES. 2013 9 228 45 ADAPTATION OF THE HUMAN POPULATION TO THE ENVIRONMENT: CURRENT KNOWLEDGE, CLUES FROM CZECH CYTOGENETIC AND "OMICS" BIOMONITORING STUDIES AND POSSIBLE MECHANISMS. THE HUMAN POPULATION IS CONTINUALLY EXPOSED TO NUMEROUS HARMFUL ENVIRONMENTAL STRESSORS, CAUSING NEGATIVE HEALTH EFFECTS AND/OR DEREGULATION OF BIOMARKER LEVELS. HOWEVER, STUDIES REPORTING NO OR EVEN POSITIVE IMPACTS OF SOME STRESSORS ON HUMANS ARE ALSO SOMETIMES PUBLISHED. THE MAIN AIM OF THIS REVIEW IS TO PROVIDE A COMPREHENSIVE OVERVIEW OF THE LAST DECADE OF CZECH BIOMONITORING RESEARCH, CONCERNING THE EFFECT OF VARIOUS LEVELS OF AIR POLLUTION (BENZO[A]PYRENE) AND RADIATION (URANIUM, X-RAY EXAMINATION AND NATURAL RADON BACKGROUND), ON THE DIFFERENTLY EXPOSED POPULATION GROUPS. BECAUSE SOME RESULTS OBTAINED FROM CYTOGENETIC STUDIES WERE OPPOSITE THAN HYPOTHESIZED, WE HAVE SEARCHED FOR A MEANINGFUL INTERPRETATION IN GENOMIC/EPIGENETIC STUDIES. A DETAILED ANALYSIS OF OUR DATA SUPPORTED BY THE STUDIES OF OTHERS AND CURRENT EPIGENETIC KNOWLEDGE, LEADS TO A HYPOTHESIS OF THE VERSATILE MECHANISM OF ADAPTATION TO ENVIRONMENTAL STRESSORS VIA DNA METHYLATION SETTINGS WHICH MAY EVEN ORIGINATE IN PRENATAL DEVELOPMENT, AND HELP TO REDUCE THE RESULTING DNA DAMAGE LEVELS. THIS HYPOTHESIS IS FULLY IN AGREEMENT WITH UNEXPECTED DATA FROM OUR STUDIES (E.G. LOWER LEVELS OF DNA DAMAGE IN SUBJECTS FROM HIGHLY POLLUTED REGIONS THAN IN CONTROLS OR IN SUBJECTS EXPOSED REPEATEDLY TO A POLLUTANT THAN IN THOSE WITHOUT PREVIOUS EXPOSURE), AND IS ALSO SUPPORTED BY DIFFERENCES IN DNA METHYLATION PATTERNS IN GROUPS FROM REGIONS WITH VARIOUS LEVELS OF POLLUTION. IN LIGHT OF THE ADAPTATION HYPOTHESIS, THE FOLLOWING POINTS MAY BE SUGGESTED FOR FUTURE RESEARCH: (I) THE CHRONIC AND ACUTE EXPOSURE OF STUDY SUBJECTS SHOULD BE DISTINGUISHED; (II) THE EXPOSURE HISTORY SHOULD BE MAPPED INCLUDING PLACE OF RESIDENCE DURING THE LIFE AND PRENATAL DEVELOPMENT; (III) CHANGES OF EPIGENETIC MARKERS SHOULD BE MONITORED OVER TIME. IN SUMMARY, INVESTIGATION OF HUMAN ADAPTATION TO THE ENVIRONMENT, ONE OF THE MOST IMPORTANT PROCESSES OF SURVIVAL, IS A NEW CHALLENGE FOR FUTURE RESEARCH IN THE FIELD OF HUMAN BIOMONITORING THAT MAY CHANGE OUR VIEW ON THE RESULTS OF BIOMARKER ANALYSES AND POTENTIAL NEGATIVE HEALTH IMPACTS OF THE ENVIRONMENT. 2017 10 301 38 AIR POLLUTION ASSOCIATED EPIGENETIC MODIFICATIONS: TRANSGENERATIONAL INHERITANCE AND UNDERLYING MOLECULAR MECHANISMS. AIR POLLUTION IS ONE OF THE LEADING CAUSES OF DEATHS IN SOUTHEAST ASIAN COUNTRIES INCLUDING INDIA. EXPOSURE TO AIR POLLUTANTS AFFECTS VITAL CELLULAR MECHANISMS AND IS INTIMATELY LINKED WITH THE ETIOLOGY OF A NUMBER OF CHRONIC DISEASES. EARLIER WORK FROM OUR LABORATORY HAS SHOWN THAT AIRBORNE PARTICULATE MATTER DISTURBS THE MITOCHONDRIAL MACHINERY AND CAUSES SIGNIFICANT DAMAGE TO THE EPIGENOME. MITOCHONDRIAL REACTIVE OXYGEN SPECIES POSSESS THE ABILITY TO TRIGGER REDOX-SENSITIVE SIGNALING MECHANISMS AND INDUCE IRREVERSIBLE EPIGENOMIC CHANGES. THE ELECTROPHILIC NATURE OF REACTIVE METABOLITES CAN DIRECTLY RESULT IN DEPROTONATION OF CYTOSINE AT C-5 POSITION OR INTERFERE WITH THE DNA METHYLTRANSFERASES ACTIVITY TO CAUSE ALTERATIONS IN DNA METHYLATION. IN ADDITION, IT ALSO PERTURBS LEVEL OF CELLULAR METABOLITES CRITICALLY INVOLVED IN DIFFERENT EPIGENETIC PROCESSES LIKE ACETYLATION AND METHYLATION OF HISTONE CODE AND DNA HYPO OR HYPERMETHYLATION. INTERESTINGLY, THESE MODIFICATIONS MAY PERSIST THROUGH DOWNSTREAM GENERATIONS AND RESULT IN THE TRANSGENERATIONAL EPIGENOMIC INHERITANCE. THIS PHENOMENON OF SUBSEQUENT TRANSFER OF EPIGENETIC MODIFICATIONS IS MAINLY ASSOCIATED WITH THE GERM CELLS AND RELIES ON THE GERMLINE STABILITY OF THE EPIGENETIC STATES. OVERALL, THE RECENT LITERATURE SUPPORTS, AND ARGUABLY STRENGTHENS, THE CONTENTION THAT AIR POLLUTION MIGHT CONTRIBUTE TO TRANSMISSION OF EPIMUTATIONS FROM GAMETES TO ZYGOTES BY INVOLVING MITOCHONDRIAL DNA, PARENTAL ALLELE IMPRINTING, HISTONE WITHHOLDING AND NON-CODING RNAS. HOWEVER, LARGER PROSPECTIVE STUDIES USING INNOVATIVE, INTEGRATED EPIGENOME-WIDE METABOLOMIC STRATEGY ARE HIGHLY WARRANTED TO ASSESS THE AIR POLLUTION INDUCED TRANSGENERATIONAL EPIGENETIC INHERITANCE AND ASSOCIATED HUMAN HEALTH EFFECTS. 2019 11 299 42 AIR POLLUTION AND DNA METHYLATION: EFFECTS OF EXPOSURE IN HUMANS. AIR POLLUTION EXPOSURE IS ESTIMATED TO CONTRIBUTE TO APPROXIMATELY SEVEN MILLION EARLY DEATHS EVERY YEAR WORLDWIDE AND MORE THAN 3% OF DISABILITY-ADJUSTED LIFE YEARS LOST. AIR POLLUTION HAS NUMEROUS HARMFUL EFFECTS ON HEALTH AND CONTRIBUTES TO THE DEVELOPMENT AND MORBIDITY OF CARDIOVASCULAR DISEASE, METABOLIC DISORDERS, AND A NUMBER OF LUNG PATHOLOGIES, INCLUDING ASTHMA AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). EMERGING DATA INDICATE THAT AIR POLLUTION EXPOSURE MODULATES THE EPIGENETIC MARK, DNA METHYLATION (DNAM), AND THAT THESE CHANGES MIGHT IN TURN INFLUENCE INFLAMMATION, DISEASE DEVELOPMENT, AND EXACERBATION RISK. SEVERAL TRAFFIC-RELATED AIR POLLUTION (TRAP) COMPONENTS, INCLUDING PARTICULATE MATTER (PM), BLACK CARBON (BC), OZONE (O(3)), NITROGEN OXIDES (NO(X)), AND POLYAROMATIC HYDROCARBONS (PAHS), HAVE BEEN ASSOCIATED WITH CHANGES IN DNAM; TYPICALLY LOWERING DNAM AFTER EXPOSURE. EFFECTS OF AIR POLLUTION ON DNAM HAVE BEEN OBSERVED ACROSS THE HUMAN LIFESPAN, BUT IT IS NOT YET CLEAR WHETHER EARLY LIFE DEVELOPMENTAL SENSITIVITY OR THE ACCUMULATION OF EXPOSURES HAVE THE MOST SIGNIFICANT EFFECTS ON HEALTH. AIR POLLUTION EXPOSURE-ASSOCIATED DNAM PATTERNS ARE OFTEN CORRELATED WITH LONG-TERM NEGATIVE RESPIRATORY HEALTH OUTCOMES, INCLUDING THE DEVELOPMENT OF LUNG DISEASES, A FOCUS IN THIS REVIEW. RECENTLY, INTERVENTIONS SUCH AS EXERCISE AND B VITAMINS HAVE BEEN PROPOSED TO REDUCE THE IMPACT OF AIR POLLUTION ON DNAM AND HEALTH. ULTIMATELY, IMPROVED KNOWLEDGE OF HOW EXPOSURE-INDUCED CHANGE IN DNAM IMPACTS HEALTH, BOTH ACUTELY AND CHRONICALLY, MAY ENABLE PREVENTATIVE AND REMEDIAL STRATEGIES TO REDUCE MORBIDITY IN POLLUTED ENVIRONMENTS. 2019 12 2849 27 FROM AIR POLLUTION TO CARDIOVASCULAR DISEASES: THE EMERGING ROLE OF EPIGENETICS. THE ASSOCIATION BETWEEN AIR POLLUTION AND A WIDE-RANGING SPECTRUM OF ACUTE AND CHRONIC DISORDERS-INCLUDING CARDIOVASCULAR DISEASES-IS WIDELY ACKNOWLEDGED. EXPOSURE TO AIRBORNE POLLUTANTS TRIGGERS HARMFUL MECHANISMS SUCH AS OXIDATIVE STRESS AND SYSTEMIC INFLAMMATION, WHICH LEAD TO INCREASED INCIDENCE OF MYOCARDIAL INFARCTION, ARTERIAL HYPERTENSION, STROKE, AND HEART FAILURE. SUSTAINED EFFORTS HAVE BEEN MADE IN RECENT YEARS TO DISCOVER HOW ENVIRONMENTAL EXPOSURES AFFECT HUMAN HEALTH THROUGH EPIGENETIC PHENOMENA, SUCH AS DNA METHYLATION, HISTONE MODIFICATIONS AND NON-CODING RNA-MEDIATED GENE REGULATION. THIS REVIEW SUMMARIZES THE CURRENT EVIDENCES ON THE RELATIONSHIP BETWEEN AIR POLLUTION EXPOSURE, EPIGENETIC ALTERATIONS AND CARDIOVASCULAR IMPACT, IN VIEW OF PRESENT IMPLICATIONS AND FUTURE PERSPECTIVES. 2020 13 360 25 AMBIENT AIR POLLUTION AND BIOMARKERS OF HEALTH EFFECT. RECENTLY, THE AIR POLLUTION SITUATION OF OUR COUNTRY IS VERY SERIOUS ALONG WITH THE DEVELOPMENT OF URBANIZATION AND INDUSTRIALIZATION. STUDIES INDICATE THAT THE EXPOSURE OF AIR POLLUTION CAN CAUSE A RISE OF INCIDENCE AND MORTALITY OF MANY DISEASES, SUCH AS CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD), ASTHMA, MYOCARDIAL INFARCTION, AND SO ON. HOWEVER, THERE IS NOW GROWING EVIDENCE SHOWING THAT SIGNIFICANT AIR POLLUTION EXPOSURES ARE ASSOCIATED WITH EARLY BIOMARKERS IN VARIOUS SYSTEMS OF THE BODY. IN ORDER TO BETTER PREVENT AND CONTROL THE DAMAGE EFFECT OF AIR POLLUTION, THIS ARTICLE SUMMARIZES COMPREHENSIVELY EPIDEMIOLOGICAL STUDIES ABOUT THE BAD EFFECTS ON THE BIOMARKERS OF RESPIRATORY SYSTEM, CARDIOVASCULAR SYSTEM, AND GENETIC AND EPIGENETIC SYSTEM EXPOSURE TO AMBIENT AIR POLLUTION. 2017 14 754 36 CARDIOVASCULAR ADAPTATIONS TO PARTICLE INHALATION EXPOSURE: MOLECULAR MECHANISMS OF THE TOXICOLOGY. AMBIENT AIR, OCCUPATIONAL SETTINGS, AND THE USE AND DISTRIBUTION OF CONSUMER PRODUCTS ALL SERVE AS CONDUITS FOR TOXICANT EXPOSURE THROUGH INHALATION. WHILE THE PULMONARY SYSTEM REMAINS A PRIMARY TARGET FOLLOWING INHALATION EXPOSURE, CARDIOVASCULAR IMPLICATIONS ARE EXCEPTIONALLY CULPABLE FOR INCREASED MORBIDITY AND MORTALITY. THE EPIDEMIOLOGICAL EVIDENCE FOR CARDIOVASCULAR DYSFUNCTION RESULTING FROM ACUTE OR CHRONIC INHALATION EXPOSURE TO PARTICULATE MATTER HAS BEEN WELL DOCUMENTED, BUT THE MECHANISMS DRIVING THE RESULTING DISTURBANCES REMAIN ELUSIVE. IN THE CURRENT REVIEW, WE AIM TO SUMMARIZE THE CELLULAR AND MOLECULAR MECHANISMS THAT ARE DIRECTLY LINKED TO CARDIOVASCULAR HEALTH FOLLOWING EXPOSURE TO A VARIETY OF INHALED TOXICANTS. THE PURPOSE OF THIS REVIEW IS TO PROVIDE A COMPREHENSIVE OVERVIEW OF THE BIOCHEMICAL CHANGES IN THE CARDIOVASCULAR SYSTEM FOLLOWING PARTICLE INHALATION EXPOSURE AND TO HIGHLIGHT POTENTIAL BIOMARKERS THAT EXIST ACROSS MULTIPLE EXPOSURE PARADIGMS. WE ATTEMPT TO INTEGRATE THESE MOLECULAR SIGNATURES IN AN EFFORT TO PROVIDE DIRECTION FOR FUTURE INVESTIGATIONS. THIS REVIEW ALSO CHARACTERIZES HOW MOLECULAR RESPONSES ARE MODIFIED IN AT-RISK POPULATIONS, SPECIFICALLY THE IMPACT OF ENVIRONMENTAL EXPOSURE DURING CRITICAL WINDOWS OF DEVELOPMENT. MATERNAL EXPOSURE TO PARTICULATE MATTER DURING GESTATION CAN LEAD TO FETAL EPIGENETIC REPROGRAMMING, RESULTING IN LONG-TERM DEFICITS TO THE CARDIOVASCULAR SYSTEM. IN BOTH DIRECT AND INDIRECT (GESTATIONAL) EXPOSURES, CONNECTING THE BIOCHEMICAL MECHANISMS WITH FUNCTIONAL DEFICITS OUTLINES PATHWAYS THAT CAN BE TARGETED FOR FUTURE THERAPEUTIC INTERVENTION. ULTIMATELY, FUTURE INVESTIGATIONS INTEGRATING "OMICS"-BASED APPROACHES WILL BETTER ELUCIDATE THE MECHANISMS THAT ARE ALTERED BY XENOBIOTIC INHALATION EXPOSURE, IDENTIFY BIOMARKERS, AND GUIDE IN CLINICAL DECISION MAKING. 2020 15 2282 37 EPIGENETIC REGULATION IN EXPOSOME-INDUCED TUMORIGENESIS: EMERGING ROLES OF NCRNAS. ENVIRONMENTAL FACTORS, INCLUDING POLLUTANTS AND LIFESTYLE, CONSTITUTE A SIGNIFICANT ROLE IN SEVERE, CHRONIC PATHOLOGIES WITH AN ESSENTIAL SOCIETAL, ECONOMIC BURDEN. THE MEASUREMENT OF ALL ENVIRONMENTAL EXPOSURES AND ASSESSING THEIR CORRELATION WITH EFFECTS ON INDIVIDUAL HEALTH IS DEFINED AS THE EXPOSOME, WHICH INTERACTS WITH OUR UNIQUE CHARACTERISTICS SUCH AS GENETICS, PHYSIOLOGY, AND EPIGENETICS. EPIGENETICS INVESTIGATES MODIFICATIONS IN THE EXPRESSION OF GENES THAT DO NOT DEPEND ON THE UNDERLYING DNA SEQUENCE. SOME STUDIES HAVE CONFIRMED THAT ENVIRONMENTAL FACTORS MAY PROMOTE DISEASE IN INDIVIDUALS OR SUBSEQUENT PROGENY THROUGH EPIGENETIC ALTERATIONS. VARIATIONS IN THE EPIGENETIC MACHINERY CAUSE A SPECTRUM OF DIFFERENT DISORDERS SINCE THESE MECHANISMS ARE MORE SENSITIVE TO THE ENVIRONMENT THAN THE GENOME, DUE TO THE INHERENT REVERSIBLE NATURE OF THE EPIGENETIC LANDSCAPE. SEVERAL EPIGENETIC MECHANISMS, INCLUDING MODIFICATIONS IN DNA (E.G., METHYLATION), HISTONES, AND NONCODING RNAS CAN CHANGE GENOME EXPRESSION UNDER THE EXOGENOUS INFLUENCE. NOTABLY, THE ROLE OF LONG NONCODING RNAS IN EPIGENETIC PROCESSES HAS NOT BEEN WELL EXPLORED IN THE CONTEXT OF EXPOSOME-INDUCED TUMORIGENESIS. IN THE PRESENT REVIEW, OUR SCOPE IS TO PROVIDE RELEVANT EVIDENCE INDICATING THAT EPIGENETIC ALTERATIONS MEDIATE THOSE DETRIMENTAL EFFECTS CAUSED BY EXPOSURE TO ENVIRONMENTAL TOXICANTS, FOCUSING MAINLY ON A MULTI-STEP REGULATION BY DIVERSE NONCODING RNAS SUBTYPES. 2022 16 3100 38 GENOMIC IMPACT OF CIGARETTE SMOKE, WITH APPLICATION TO THREE SMOKING-RELATED DISEASES. THERE IS CONSIDERABLE EVIDENCE THAT INHALED TOXICANTS SUCH AS CIGARETTE SMOKE CAN CAUSE BOTH IRREVERSIBLE CHANGES TO THE GENETIC MATERIAL (DNA MUTATIONS) AND PUTATIVELY REVERSIBLE CHANGES TO THE EPIGENETIC LANDSCAPE (CHANGES IN THE DNA METHYLATION AND CHROMATIN MODIFICATION STATE). THE DISEASES THAT ARE BELIEVED TO INVOLVE GENETIC AND EPIGENETIC PERTURBATIONS INCLUDE LUNG CANCER, CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD), AND CARDIOVASCULAR DISEASE (CVD), ALL OF WHICH ARE STRONGLY LINKED EPIDEMIOLOGICALLY TO CIGARETTE SMOKING. IN THIS REVIEW, WE HIGHLIGHT THE SIGNIFICANCE OF GENOMICS AND EPIGENOMICS IN THESE MAJOR SMOKING-RELATED DISEASES. WE ALSO SUMMARIZE THE IN VITRO AND IN VIVO FINDINGS ON THE SPECIFIC PERTURBATIONS THAT SMOKE AND ITS CONSTITUENT COMPOUNDS CAN INFLICT UPON THE GENOME, PARTICULARLY ON THE PULMONARY SYSTEM. FINALLY, WE REVIEW STATE-OF-THE-ART GENOMICS AND NEW TECHNIQUES SUCH AS HIGH-THROUGHPUT SEQUENCING AND GENOME-WIDE CHROMATIN ASSAYS, RAPIDLY EVOLVING TECHNIQUES WHICH HAVE ALLOWED EPIGENETIC CHANGES TO BE CHARACTERIZED AT THE GENOME LEVEL. THESE TECHNIQUES HAVE THE POTENTIAL TO SIGNIFICANTLY IMPROVE OUR UNDERSTANDING OF THE SPECIFIC MECHANISMS BY WHICH EXPOSURE TO ENVIRONMENTAL CHEMICALS CAUSES DISEASE. SUCH MECHANISTIC KNOWLEDGE PROVIDES A VARIETY OF OPPORTUNITIES FOR ENHANCED PRODUCT SAFETY ASSESSMENT AND THE DISCOVERY OF NOVEL THERAPEUTIC INTERVENTIONS. 2012 17 2648 37 EPIGENOMIC TARGETS FOR THE TREATMENT OF RESPIRATORY DISEASE. BACKGROUND: A NUMBER OF PROCESSES LEAD TO EPIGENETIC AND EPIGENOMIC MODIFICATIONS. OBJECTIVE: TO ADDRESS THE IMPORTANCE OF EPIGENOMICS IN RESPIRATORY DISEASE. METHODS: STUDIES OF EPIGENOMICS WERE ANALYSED IN RELATION TO CHRONIC RESPIRATORY DISEASES. RESULTS/CONCLUSION: IN LUNG CANCER AND MESOTHELIOMA, A NUMBER OF GENES INVOLVED IN CARCINOGENESIS HAVE BEEN DEMONSTRATED TO BE HYPERMETHYLATED, IMPLICATING EPIGENOMIC CHANGES IN THE AETIOLOGY OF THESE CANCERS. HYPERMETHYLATED GENES HAVE ALSO BEEN ASSOCIATED WITH LUNG CANCER RECURRENCE, INDICATING EPIGENOMIC REGULATION OF METASTASIS. IN AIRWAY DISEASES, MODULATION OF HISTONE FUNCTION MAY ACTIVATE INFLAMMATORY MECHANISMS IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE PATIENTS AND LEAD TO RELATIVE STEROID RESISTANCE. THERE IS EMERGING EVIDENCE FOR THE ROLE OF EPIGENETIC CHANGES IN CHRONIC LUNG DISEASES SUCH AS ASTHMA, INCLUDING RESPONSES TO ENVIRONMENTAL EXPOSURES IN UTERO AND TO THE EFFECTS OF AIR POLLUTION. INSIGHT INTO EPIGENOMICS WILL LEAD TO THE DEVELOPMENT OF NOVEL BIOMARKERS AND TREATMENT TARGETS IN RESPIRATORY DISEASES. 2009 18 528 44 ASTHMA EPIGENETICS. ASTHMA IS THE MOST COMMON CHRONIC DISEASE OF CHILDHOOD, AND A GROWING BODY OF EVIDENCE INDICATES THAT EPIGENETIC VARIATIONS MAY MEDIATE THE EFFECTS OF ENVIRONMENTAL EXPOSURES ON THE DEVELOPMENT AND NATURAL HISTORY OF ASTHMA. EPIGENETICS IS THE STUDY OF MITOTICALLY OR MEIOTICALLY HERITABLE CHANGES IN GENE EXPRESSION THAT OCCUR WITHOUT DIRECTLY ALTERING THE DNA SEQUENCE. DNA METHYLATION, HISTONE MODIFICATIONS AND MICRORNAS ARE MAJOR EPIGENETIC VARIATIONS IN HUMANS THAT ARE CURRENTLY BEING INVESTIGATED FOR ASTHMA ETIOLOGY AND NATURAL HISTORY. DNA METHYLATION RESULTS FROM ADDITION OF A METHYL GROUP TO THE 5 POSITION OF A CYTOSINE RING AND OCCURS ALMOST EXCLUSIVELY ON A CYTOSINE IN A CPG DINUCLEOTIDE. HISTONE MODIFICATIONS INVOLVE POSTTRANSLATIONAL MODIFICATIONS SUCH AS ACETYLATION, METHYLATION, PHOSPHORYLATION AND UBIQUITINATION ON THE TAILS OF CORE HISTONES. MICRORNAS ARE SHORT ~22 NUCLEOTIDE LONG, NON-CODING, SINGLE-STRANDED RNAS THAT BINDS TO COMPLEMENTARY SEQUENCES IN THE TARGET MRNAS, USUALLY RESULTING IN GENE SILENCING. WHILE MANY STUDIES HAVE DOCUMENTED RELATIONSHIPS OF ENVIRONMENTAL EXPOSURES THAT HAVE BEEN IMPLICATED IN ASTHMA ETIOLOGY WITH EPIGENETIC ALTERATIONS, TO DATE, FEW STUDIES HAVE DIRECTLY LINKED EPIGENETIC VARIATIONS WITH ASTHMA DEVELOPMENT. THERE ARE SEVERAL METHODOLOGICAL CHALLENGES IN STUDYING THE EPIGENETICS OF ASTHMA. IN THIS CHAPTER, THE INFLUENCE OF EPIGENETIC VARIATIONS ON ASTHMA PATHOPHYSIOLOGY, METHODOLOGICAL CONCERNS IN CONDUCTING EPIGENETIC RESEARCH AND FUTURE DIRECTION OF ASTHMA EPIGENETICS RESEARCH ARE DISCUSSED. 2014 19 4767 30 NUCLEAR AND MITOCHONDRIAL DNA ALTERATIONS IN NEWBORNS WITH PRENATAL EXPOSURE TO CIGARETTE SMOKE. NEWBORNS EXPOSED TO MATERNAL CIGARETTE SMOKE (CS) IN UTERO HAVE AN INCREASED RISK OF DEVELOPING CHRONIC DISEASES, CANCER, AND ACQUIRING DECREASED COGNITIVE FUNCTION IN ADULTHOOD. ALTHOUGH THE LITERATURE REPORTS MANY DELETERIOUS EFFECTS ASSOCIATED WITH MATERNAL CIGARETTE SMOKING ON THE FETUS, THE MOLECULAR ALTERATIONS AND MECHANISMS OF ACTION ARE NOT YET CLEAR. SMOKING MAY ACT DIRECTLY ON NUCLEAR DNA BY INDUCING MUTATIONS OR EPIGENETIC MODIFICATIONS. RECENT STUDIES ALSO INDICATE THAT SMOKING MAY ACT ON MITOCHONDRIAL DNA BY INDUCING A CHANGE IN THE NUMBER OF COPIES TO MAKE UP FOR THE DAMAGE CAUSED BY SMOKING ON THE RESPIRATORY CHAIN AND LACK OF ENERGY. IN ADDITION, INDIVIDUAL GENETIC SUSCEPTIBILITY PLAYS A SIGNIFICANT ROLE IN DETERMINING THE EFFECTS OF SMOKING DURING DEVELOPMENT. FURTHERMORE, PRIOR EXPOSURE OF PATERNAL AND MATERNAL GAMETES TO CIGARETTE SMOKE MAY AFFECT THE HEALTH OF THE DEVELOPING INDIVIDUAL, NOT ONLY THE IN UTERO EXPOSURE. THIS REVIEW EXAMINES THE GENETIC AND EPIGENETIC ALTERATIONS IN NUCLEAR AND MITOCHONDRIAL DNA ASSOCIATED WITH SMOKE EXPOSURE DURING THE MOST SENSITIVE PERIODS OF DEVELOPMENT (PRIOR TO CONCEPTION, PRENATAL AND EARLY POSTNATAL) AND ASSESSES HOW SUCH CHANGES MAY HAVE CONSEQUENCES FOR BOTH FETAL GROWTH AND DEVELOPMENT. 2015 20 1546 25 DNA METHYLATION IN NASAL EPITHELIUM: STRENGTHS AND LIMITATIONS OF AN EMERGENT BIOMARKER FOR CHILDHOOD ASTHMA. ASTHMA IS ONE OF THE MOST WIDESPREAD CHRONIC RESPIRATORY CONDITIONS. THIS DISEASE PRIMARILY DEVELOPS IN CHILDHOOD AND IS INFLUENCED BY DIFFERENT FACTORS, MAINLY GENETICS AND ENVIRONMENTAL FACTORS. DNA METHYLATION IS AN EPIGENETIC MECHANISM WHICH MAY REPRESENT A BRIDGE BETWEEN THESE TWO FACTORS, PROVIDING A TOOL TO COMPREHEND THE INTERACTION BETWEEN GENETICS AND ENVIRONMENT. MOST EPIDEMIOLOGICAL STUDIES IN THIS FIELD HAVE BEEN CONDUCTED USING BLOOD SAMPLES, ALTHOUGH DNA METHYLATION MARKS IN BLOOD MAY NOT BE RELIABLE FOR DRAWING EXHAUSTIVE CONCLUSIONS ABOUT DNA METHYLATION IN THE AIRWAYS. BECAUSE OF THE ROLE OF NASAL EPITHELIUM IN ASTHMA AND THE TISSUE SPECIFICITY OF DNA METHYLATION, STUDYING THE RELATIONSHIP BETWEEN DNA METHYLATION AND CHILDHOOD ASTHMA MIGHT REVEAL CRUCIAL INFORMATION ABOUT THIS WIDESPREAD RESPIRATORY DISEASE. THE PURPOSE OF THIS REVIEW IS TO DESCRIBE CURRENT FINDINGS IN THIS FIELD OF RESEARCH. WE WILL PRESENT A VIEWPOINT OF SELECTED STUDIES, CONSIDER STRENGTHS AND LIMITATIONS, AND PROPOSE FUTURE RESEARCH IN THIS AREA. 2020