1 1177 141 CONTROL OF BREATHING AND THE CIRCULATION IN HIGH-ALTITUDE MAMMALS AND BIRDS. HYPOXIA IS AN UNREMITTING STRESSOR AT HIGH ALTITUDES THAT PLACES A PREMIUM ON OXYGEN TRANSPORT BY THE RESPIRATORY AND CARDIOVASCULAR SYSTEMS. PHENOTYPIC PLASTICITY AND GENOTYPIC ADAPTATION AT VARIOUS STEPS IN THE O2 CASCADE COULD HELP OFFSET THE EFFECTS OF HYPOXIA ON CELLULAR O2 SUPPLY IN HIGH-ALTITUDE NATIVES. IN THIS REVIEW, WE WILL DISCUSS THE UNIQUE MECHANISMS BY WHICH VENTILATION, CARDIAC OUTPUT, AND BLOOD FLOW ARE CONTROLLED IN HIGH-ALTITUDE MAMMALS AND BIRDS. ACCLIMATIZATION TO HIGH ALTITUDES LEADS TO SOME CHANGES IN RESPIRATORY AND CARDIOVASCULAR CONTROL THAT INCREASE O2 TRANSPORT IN HYPOXIA (E.G., VENTILATORY ACCLIMATIZATION TO HYPOXIA). HOWEVER, ACCLIMATIZATION OR DEVELOPMENT IN HYPOXIA CAN ALSO MODIFY CARDIORESPIRATORY CONTROL IN WAYS THAT ARE MALADAPTIVE FOR O2 TRANSPORT. HYPOXIA RESPONSES THAT AROSE AS SHORT-TERM SOLUTIONS TO O2 DEPRIVATION (E.G., PERIPHERAL VASOCONSTRICTION) OR REGIONAL VARIATION IN O2 LEVELS IN THE LUNGS (I.E., HYPOXIC PULMONARY VASOCONSTRICTION) ARE DETRIMENTAL AT IN CHRONIC HIGH-ALTITUDE HYPOXIA. EVOLVED CHANGES IN CARDIORESPIRATORY CONTROL HAVE ARISEN IN MANY HIGH-ALTITUDE TAXA, INCLUDING INCREASES IN EFFECTIVE VENTILATION, ATTENUATION OF HYPOXIC PULMONARY VASOCONSTRICTION, AND CHANGES IN CATECHOLAMINE SENSITIVITY OF THE HEART AND SYSTEMIC VASCULATURE. PARALLEL EVOLUTION OF SOME OF THESE CHANGES IN INDEPENDENT HIGHLAND LINEAGES SUPPORTS THEIR ADAPTIVE SIGNIFICANCE. MUCH LESS IS KNOWN ABOUT THE GENOMIC BASES AND POTENTIAL INTERACTIVE EFFECTS OF ADAPTATION, ACCLIMATIZATION, DEVELOPMENTAL PLASTICITY, AND TRANS-GENERATIONAL EPIGENETIC TRANSFER ON CARDIORESPIRATORY CONTROL. FUTURE WORK TO UNDERSTAND THESE VARIOUS INFLUENCES ON BREATHING AND CIRCULATION IN HIGH-ALTITUDE NATIVES WILL HELP ELUCIDATE HOW COMPLEX PHYSIOLOGICAL SYSTEMS CAN BE PUSHED TO THEIR LIMITS TO MAINTAIN CELLULAR FUNCTION IN HYPOXIA. 2015 2 4109 38 MECHANISMS AND DRUG THERAPY OF PULMONARY HYPERTENSION AT HIGH ALTITUDE. PULMONARY VASOCONSTRICTION REPRESENTS A PHYSIOLOGICAL ADAPTIVE MECHANISM TO HIGH ALTITUDE. IF EXAGGERATED, HOWEVER, IT IS ASSOCIATED WITH IMPORTANT MORBIDITY AND MORTALITY. RECENT MECHANISTIC STUDIES USING SHORT-TERM ACUTE HIGH ALTITUDE EXPOSURE HAVE PROVIDED INSIGHT INTO THE IMPORTANCE OF DEFECTIVE VASCULAR ENDOTHELIAL AND RESPIRATORY EPITHELIAL NITRIC OXIDE (NO) SYNTHESIS, INCREASED ENDOTHELIN-1 BIOAVAILABILITY, AND OVERACTIVATION OF THE SYMPATHETIC NERVOUS SYSTEM IN CAUSING EXAGGERATED HYPOXIC PULMONARY HYPERTENSION IN HUMANS. BASED ON THESE STUDIES, DRUGS THAT INCREASE NO BIOAVAILABILITY, ATTENUATE ENDOTHELIN-1 INDUCED PULMONARY VASOCONSTRICTION, OR PREVENT EXAGGERATED SYMPATHETIC ACTIVATION HAVE BEEN SHOWN TO BE USEFUL FOR THE TREATMENT/PREVENTION OF EXAGGERATED PULMONARY HYPERTENSION DURING ACUTE SHORT-TERM HIGH ALTITUDE EXPOSURE. THE MECHANISMS UNDERPINNING CHRONIC PULMONARY HYPERTENSION IN HIGH ALTITUDE DWELLERS ARE LESS WELL UNDERSTOOD, BUT RECENT EVIDENCE SUGGESTS THAT THEY DIFFER IN SOME ASPECTS FROM THOSE INVOLVED IN SHORT-TERM ADAPTATION TO HIGH ALTITUDE. THESE DIFFERENCES HAVE CONSEQUENCES FOR THE CHOICE OF THE TREATMENT FOR CHRONIC PULMONARY HYPERTENSION AT HIGH ALTITUDE. FINALLY, RECENT DATA INDICATE THAT FETAL PROGRAMMING OF PULMONARY VASCULAR DYSFUNCTION IN OFFSPRING OF PREECLAMPSIA AND CHILDREN GENERATED BY ASSISTED REPRODUCTIVE TECHNOLOGIES REPRESENTS A NOVEL AND FREQUENT CAUSE OF PULMONARY HYPERTENSION AT HIGH ALTITUDE. IN ANIMAL MODELS OF FETAL PROGRAMMING OF HYPOXIC PULMONARY HYPERTENSION, EPIGENETIC MECHANISMS PLAY A ROLE, AND TARGETING OF THESE MECHANISMS WITH DRUGS LOWERS PULMONARY ARTERY PRESSURE. IF EPIGENETIC MECHANISMS ALSO ARE OPERATIONAL IN THE FETAL PROGRAMMING OF PULMONARY VASCULAR DYSFUNCTION IN HUMANS, SUCH DRUGS MAY BECOME NOVEL TOOLS FOR THE TREATMENT OF HYPOXIC PULMONARY HYPERTENSION. 2013 3 2023 30 EPIGENETIC CHANGES BY DNA METHYLATION IN CHRONIC AND INTERMITTENT HYPOXIA. DNA METHYLATION OF CYTOSINE RESIDUES IS A WELL-STUDIED EPIGENETIC CHANGE, WHICH REGULATES GENE TRANSCRIPTION BY ALTERING ACCESSIBILITY FOR TRANSCRIPTION FACTORS. HYPOXIA IS A PERVASIVE STIMULUS THAT AFFECTS MANY PHYSIOLOGICAL PROCESSES. THE CIRCULATORY AND RESPIRATORY SYSTEMS ADAPT TO CHRONIC SUSTAINED HYPOXIA, SUCH AS THAT ENCOUNTERED DURING A HIGH-ALTITUDE SOJOURN. MANY PEOPLE LIVING AT SEA LEVEL EXPERIENCE CHRONIC INTERMITTENT HYPOXIA (IH) DUE TO SLEEP APNEA, WHICH LEADS TO CARDIOVASCULAR AND RESPIRATORY MALADAPTATION. THIS ARTICLE PRESENTS A BRIEF UPDATE ON EMERGING EVIDENCE SUGGESTING THAT CHANGES IN DNA METHYLATION CONTRIBUTE TO PATHOLOGIES CAUSED BY CHRONIC IH AND POTENTIALLY MEDIATE ADAPTATIONS TO CHRONIC SUSTAINED HYPOXIA BY AFFECTING THE HYPOXIA-INDUCIBLE FACTOR (HIF) SIGNALING PATHWAY. 2017 4 2738 41 EXPOSOMES TO EXOSOMES: EXOSOMES AS TOOLS TO STUDY EPIGENETIC ADAPTIVE MECHANISMS IN HIGH-ALTITUDE HUMANS. HUMANS ON EARTH INHABIT A WIDE RANGE OF ENVIRONMENTAL CONDITIONS AND SOME ENVIRONMENTS ARE MORE CHALLENGING FOR HUMAN SURVIVAL THAN OTHERS. HOWEVER, MANY LIVING BEINGS, INCLUDING HUMANS, HAVE DEVELOPED ADAPTIVE MECHANISMS TO LIVE IN SUCH INHOSPITABLE, HARSH ENVIRONMENTS. AMONG DIFFERENT DIFFICULT ENVIRONMENTS, HIGH-ALTITUDE LIVING IS ESPECIALLY DEMANDING BECAUSE OF DIMINISHED PARTIAL PRESSURE OF OXYGEN AND RESULTING CHRONIC HYPOBARIC HYPOXIA. THIS RESULTS IN POOR BLOOD OXYGENATION AND REDUCES AEROBIC OXIDATIVE RESPIRATION IN THE MITOCHONDRIA, LEADING TO INCREASED REACTIVE OXYGEN SPECIES GENERATION AND ACTIVATION OF HYPOXIA-INDUCIBLE GENE EXPRESSION. GENETIC MECHANISMS IN THE ADAPTATION TO HIGH ALTITUDE IS WELL-STUDIED, BUT THERE ARE ONLY LIMITED STUDIES REGARDING THE ROLE OF EPIGENETIC MECHANISMS. THE PURPOSE OF THIS REVIEW IS TO UNDERSTAND THE EPIGENETIC MECHANISMS BEHIND HIGH-ALTITUDE ADAPTIVE AND MALADAPTIVE PHENOTYPES. HYPOBARIC HYPOXIA IS A FORM OF CELLULAR HYPOXIA, WHICH IS SIMILAR TO THE ONE SUFFERED BY CRITICALLY-ILL HYPOXEMIA PATIENTS. THUS, UNDERSTANDING THE ADAPTIVE EPIGENETIC SIGNALS OPERATING IN IN HIGH-ALTITUDE ADJUSTED INDIGENOUS POPULATIONS MAY HELP IN THERAPEUTICALLY MODULATING SIGNALING PATHWAYS IN HYPOXEMIA PATIENTS BY COPYING THE MOST SUCCESSFUL EPIGENOTYPE. IN ADDITION, WE HAVE SUMMARIZED THE CURRENT INFORMATION ABOUT EXOSOMES IN HYPOXIA RESEARCH AND PROSPECTS TO USE THEM AS DIAGNOSTIC TOOLS TO STUDY THE EPIGENOME OF HIGH-ALTITUDE ADAPTED HEALTHY OR MALADAPTED INDIVIDUALS. 2021 5 5048 46 PHARMACOLOGICAL APPROACHES IN EITHER INTERMITTENT OR PERMANENT HYPOXIA: A TALE OF TWO EXPOSURES. HYPOXIA INDUCES SEVERAL RESPONSES AT CARDIOVASCULAR, PULMONARY AND REPRODUCTIVE LEVELS, WHICH MAY LEAD TO CHRONIC DISEASES. THIS IS RELEVANT IN HUMAN POPULATIONS EXPOSED TO HIGH ALTITUDE (HA), IN EITHER CHRONIC CONTINUOUS (PERMANENT INHABITANTS) OR INTERMITTENT FASHION (HA WORKERS, TOURISTS AND MOUNTAINEERS). IN CHILE, IT IS ESTIMATED THAT 1.000.000 PEOPLE LIVE AT HIGHLANDS AND MORE THAN 55.000 WORK IN HA SHIFTS. INITIAL RESPONSES TO HYPOXIA ARE COMPENSATORY AND INDUCE ACTIVATION OF CARDIOPROTECTIVE MECHANISMS, SUCH AS THOSE SEEN UNDER INTERMITTENT HYPOBARIC (IH) HYPOXIA, EVENTS THAT COULD MEDIATE PRECONDITIONING. HOWEVER, WHENEVER HYPOXIA IS PROLONGED, THE CHRONIC ACTIVATION OF CELLULAR RESPONSES INDUCES LONG-LASTING MODIFICATIONS THAT MAY RESULT IN ACCLIMATIZATION OR PRODUCE MALADAPTIVE CHANGES WITH INCREASE IN CARDIOVASCULAR RISK. HA EXPOSURE DURING PREGNANCY INDUCES HYPOXIA AND OXIDATIVE STRESS, WHICH IN TURN MAY PROMOTE CELLULAR RESPONSES AND EPIGENETIC MODIFICATIONS RESULTING IN SEVERE IMPAIRMENT IN GROWTH AND DEVELOPMENT. SADLY, THIS CONDITION IS ACCOMPANIED WITH AN INCREASED FETAL AND NEONATAL MORBI-MORTALITY. FURTHER, DEVELOPMENTAL HYPOXIA MAY PROGRAM CARDIO-PULMONARY CIRCULATIONS LATER IN POSTNATAL LIFE, ENDING IN VASCULAR STRUCTURAL AND FUNCTIONAL ALTERATIONS WITH AUGMENTED RISK ON PULMONARY AND CARDIOVASCULAR FAILURE. ADDITIONALLY, PERMANENT HA INHABITANTS HAVE AUGMENTED RISK AND PREVALENCE OF CHRONIC HYPOXIC PULMONARY HYPERTENSION, RIGHT VENTRICULAR HYPERTROPHY AND CARDIOPULMONARY REMODELING. SIMILAR RESPONSES ARE SEEN IN ADULTS THAT ARE INTERMITTENTLY EXPOSED TO CHRONIC HYPOXIA (CH) SUCH AS SHIFT WORKERS IN HA AREAS. THE MECHANISMS INVOLVED DETERMINING THE IMMEDIATE, SHORT AND LONG-LASTING EFFECTS ARE STILL UNCLEAR. FOR SEVERAL YEARS, THE STUDY OF THE RESPONSES TO HYPOXIC INSULTS AND PHARMACOLOGICAL TARGETS HAS BEEN THE MOTIVATION OF OUR GROUP. THIS REVIEW DESCRIBES SOME OF THE MECHANISMS UNDERLYING HYPOXIC RESPONSES AND POTENTIAL THERAPEUTIC APPROACHES WITH ANTIOXIDANTS SUCH AS MELATONIN, ASCORBATE, OMEGA 3 (OMEGA3) OR COMPOUNDS THAT INCREASE THE NITRIC OXIDE (NO) BIOAVAILABILITY. 2015 6 2567 31 EPIGENETICS MODIFIERS: POTENTIAL HUB FOR UNDERSTANDING AND TREATING NEURODEVELOPMENTAL DISORDERS FROM HYPOXIC INJURY. BACKGROUND: THE FETAL BRAIN IS ADAPTED TO THE HYPOXIC CONDITIONS PRESENT DURING NORMAL IN UTERO DEVELOPMENT. RELATIVELY MORE HYPOXIC STATES, EITHER CHRONIC OR ACUTE, ARE PATHOLOGIC AND CAN LEAD TO SIGNIFICANT LONG-TERM NEURODEVELOPMENTAL SEQUELAE. IN UTERO HYPOXIC INJURY IS ASSOCIATED WITH NEONATAL MORTALITY AND MILLIONS OF LIVES LIVED WITH VARYING DEGREES OF DISABILITY. MAIN BODY: GENETIC STUDIES OF CHILDREN WITH NEURODEVELOPMENTAL DISEASE INDICATE THAT EPIGENETIC MODIFIERS REGULATING DNA METHYLATION AND HISTONE REMODELING ARE CRITICAL FOR NORMAL BRAIN DEVELOPMENT. EPIGENETIC MODIFIERS ARE ALSO REGULATED BY ENVIRONMENTAL STIMULI, SUCH AS HYPOXIA. INDEED, EPIGENETIC MODIFIERS THAT ARE MUTATED IN CHILDREN WITH GENETIC NEURODEVELOPMENTAL DISEASES ARE REGULATED BY HYPOXIA IN A NUMBER OF PRECLINICAL MODELS AND MAY BE PART OF THE MECHANISM FOR THE LONG-TERM NEURODEVELOPMENTAL SEQUELAE SEEM IN CHILDREN WITH HYPOXIC BRAIN INJURY. THUS, A COMPREHENSIVE UNDERSTANDING THE ROLE OF DNA METHYLATION AND HISTONE MODIFICATIONS IN HYPOXIC INJURY IS CRITICAL FOR DEVELOPING NOVEL STRATEGIES TO TREAT CHILDREN WITH HYPOXIC INJURY. CONCLUSIONS: THIS REVIEW FOCUSES ON OUR CURRENT UNDERSTANDING OF THE INTERSECTION BETWEEN EPIGENETICS, BRAIN DEVELOPMENT, AND HYPOXIA. OPPORTUNITIES FOR THE USE OF EPIGENETICS AS BIOMARKERS OF NEURODEVELOPMENTAL DISEASE AFTER HYPOXIC INJURY AND POTENTIAL CLINICAL EPIGENETICS TARGETS TO IMPROVE OUTCOMES AFTER INJURY ARE ALSO DISCUSSED. WHILE THERE HAVE BEEN MANY PUBLISHED STUDIES ON THE EPIGENETICS OF HYPOXIA, MORE ARE NEEDED IN THE DEVELOPING BRAIN IN ORDER TO DETERMINE WHICH EPIGENETIC PATHWAYS MAY BE MOST IMPORTANT FOR MITIGATING THE LONG-TERM CONSEQUENCES OF HYPOXIC BRAIN INJURY. 2020 7 3428 36 HUMANS AT HIGH ALTITUDE: HYPOXIA AND FETAL GROWTH. HIGH-ALTITUDE STUDIES OFFER INSIGHT INTO THE EVOLUTIONARY PROCESSES AND PHYSIOLOGICAL MECHANISMS AFFECTING THE EARLY PHASES OF THE HUMAN LIFESPAN. CHRONIC HYPOXIA SLOWS FETAL GROWTH AND REDUCES THE PREGNANCY-ASSOCIATED RISE IN UTERINE ARTERY (UA) BLOOD FLOW. MULTIGENERATIONAL VS. SHORTER-TERM HIGH-ALTITUDE RESIDENTS ARE PROTECTED FROM THE ALTITUDE-ASSOCIATED REDUCTIONS IN UA FLOW AND FETAL GROWTH. PRESENTLY UNKNOWN IS WHETHER THIS FETAL-GROWTH PROTECTION IS DUE TO THE GREATER DELIVERY OR METABOLISM OF OXYGEN, GLUCOSE OR OTHER SUBSTRATES OR TO OTHER CONSIDERATIONS SUCH AS MECHANICAL FACTORS PROTECTING FRAGILE FETAL VILLI, THE CREATION OF A RESERVE PROTECTING AGAINST ISCHEMIA/REPERFUSION INJURY, OR IMPROVED PLACENTAL O(2) TRANSFER AS THE RESULT OF NARROWING THE A-V O(2) DIFFERENCE AND RAISING UTERINE P(V)O(2). PLACENTAL GROWTH AND DEVELOPMENT APPEAR TO BE NORMAL OR MODIFIED AT HIGH ALTITUDE IN WAYS LIKELY TO BENEFIT DIFFUSION. MUCH REMAINS TO BE LEARNED CONCERNING THE EFFECTS OF CHRONIC HYPOXIA ON EMBRYONIC DEVELOPMENT. FURTHER RESEARCH IS REQUIRED FOR IDENTIFYING THE FETOPLACENTAL AND MATERNAL MECHANISMS RESPONSIBLE FOR TRANSFORMING THE MATERNAL VASCULATURE AND REGULATING UA BLOOD FLOW AND FETAL GROWTH. GENOMIC AS WELL AS EPIGENETIC STUDIES ARE OPENING NEW AVENUES OF INVESTIGATION THAT CAN YIELD INSIGHTS INTO THE BASIC PATHWAYS AND EVOLUTIONARY PROCESSES INVOLVED. 2011 8 4197 31 METABOLIC PROFILES IN OVINE CAROTID ARTERIES WITH DEVELOPMENTAL MATURATION AND LONG-TERM HYPOXIA. BACKGROUND: LONG-TERM HYPOXIA (LTH) IS AN IMPORTANT STRESSOR RELATED TO HEALTH AND DISEASE DURING DEVELOPMENT. AT DIFFERENT TIME POINTS FROM FETUS TO ADULT, WE ARE EXPOSED TO HYPOXIC STRESS BECAUSE OF PLACENTAL INSUFFICIENCY, HIGH-ALTITUDE RESIDENCE, SMOKING, CHRONIC ANEMIA, PULMONARY, AND HEART DISORDERS, AS WELL AS CANCERS. INTRAUTERINE HYPOXIA CAN LEAD TO FETAL GROWTH RESTRICTION AND LONG-TERM SEQUELAE SUCH AS COGNITIVE IMPAIRMENTS, HYPERTENSION, CARDIOVASCULAR DISORDERS, DIABETES, AND SCHIZOPHRENIA. SIMILARLY, PROLONGED HYPOXIC EXPOSURE DURING ADULT LIFE CAN LEAD TO ACUTE MOUNTAIN SICKNESS, CHRONIC FATIGUE, CHRONIC HEADACHE, COGNITIVE IMPAIRMENT, ACUTE CEREBRAL AND/OR PULMONARY EDEMA, AND DEATH. AIM: LTH ALSO CAN LEAD TO ALTERATION IN METABOLITES SUCH AS FUMARATE, 2-OXOGLUTARATE, MALATE, AND LACTATE, WHICH ARE LINKED TO EPIGENETIC REGULATION OF GENE EXPRESSION. IMPORTANTLY, DURING THE INTRAUTERINE LIFE, A FETUS IS UNDER A RELATIVE HYPOXIC ENVIRONMENT, AS COMPARED TO NEWBORN OR ADULT. THUS, THE CHANGES IN GENE EXPRESSION WITH DEVELOPMENT FROM FETUS TO NEWBORN TO ADULT MAY BE AS A CONSEQUENCE OF UNDERLYING CHANGES IN THE METABOLIC PROFILE BECAUSE OF THE HYPOXIC ENVIRONMENT ALONG WITH DEVELOPMENTAL MATURATION. TO EXAMINE THIS POSSIBILITY, WE EXAMINED THE METABOLIC PROFILE IN CAROTID ARTERIES FROM NEAR-TERM FETUS, NEWBORN, AND ADULT SHEEP IN BOTH NORMOXIC AND LONG-TERM HYPOXIC ACCLIMATIZED GROUPS. RESULTS: OUR RESULTS DEMONSTRATE THAT LTH DIFFERENTIALLY REGULATED GLUCOSE METABOLISM, MITOCHONDRIAL METABOLISM, NICOTINAMIDE COFACTOR METABOLISM, OXIDATIVE STRESS AND ANTIOXIDANTS, MEMBRANE LIPID HYDROLYSIS, AND FREE FATTY ACID METABOLISM, EACH OF WHICH MAY PLAY A ROLE IN GENETIC-EPIGENETIC REGULATION. 2015 9 3814 30 INTRAUTERINE HYPOXIA AND EPIGENETIC PROGRAMMING IN LUNG DEVELOPMENT AND DISEASE. CLINICALLY, INTRAUTERINE HYPOXIA IS THE FOREMOST CAUSE OF PERINATAL MORBIDITY AND DEVELOPMENTAL PLASTICITY IN THE FETUS AND NEWBORN INFANT. UNDER HYPOXIA, DEVIATIONS OCCUR IN THE LUNG CELL EPIGENOME. EPIGENETIC MECHANISMS (E.G., DNA METHYLATION, HISTONE MODIFICATION, AND MIRNA EXPRESSION) CONTROL PHENOTYPIC PROGRAMMING AND ARE ASSOCIATED WITH PHYSIOLOGICAL RESPONSES AND THE RISK OF DEVELOPMENTAL DISORDERS, SUCH AS BRONCHOPULMONARY DYSPLASIA. THIS DEVELOPMENTAL DISORDER IS THE MOST FREQUENT CHRONIC PULMONARY COMPLICATION IN PRETERM LABOR. THE PATHOGENESIS OF THIS DISEASE INVOLVES MANY FACTORS, INCLUDING ABERRANT OXYGEN CONDITIONS AND MECHANICAL VENTILATION-MEDIATED LUNG INJURY, INFECTION/INFLAMMATION, AND EPIGENETIC/GENETIC RISK FACTORS. THIS REVIEW IS FOCUSED ON VARIOUS ASPECTS RELATED TO INTRAUTERINE HYPOXIA AND EPIGENETIC PROGRAMMING IN LUNG DEVELOPMENT AND DISEASE, SUMMARIZES OUR CURRENT KNOWLEDGE OF HYPOXIA-INDUCED EPIGENETIC PROGRAMMING AND DISCUSSES POTENTIAL THERAPEUTIC INTERVENTIONS FOR LUNG DISEASE. 2021 10 1371 35 DEVELOPMENTAL ORIGINS OF HEALTH AND DISEASE: NEW INSIGHTS. EPIDEMIOLOGICAL AND ANIMAL STUDIES SHOW THAT SMALL CHANGES IN THE DEVELOPMENTAL ENVIRONMENT CAN INDUCE PHENOTYPIC CHANGES AFFECTING AN INDIVIDUAL'S RESPONSES TO THEIR LATER ENVIRONMENT. THESE MAY ALTER THE RISK OF CHRONIC DISEASE SUCH AS METABOLIC SYNDROME OR CARDIOVASCULAR DISEASE. RECENT RESEARCH SHOWS THAT ANIMALS EXPOSED TO SUCH A MISMATCH BETWEEN PRENATAL AND POSTNATAL ENVIRONMENT DEVELOP OBESITY, REDUCED ACTIVITY, LEPTIN AND INSULIN RESISTANCE, ELEVATED BLOOD PRESSURE AND VASCULAR ENDOTHELIAL DYSFUNCTION. EPIGENETIC PROCESSES ARE INVOLVED IN SUCH EFFECTS, TARGETED TO PROMOTER REGIONS OF SPECIFIC GENES IN SPECIFIC TISSUES. SUCH FINE CONTROL OF GENE EXPRESSION SUGGESTS THAT THE MECHANISMS HAVE BEEN RETAINED THROUGH EVOLUTION THROUGH THEIR ADAPTIVE ADVANTAGE, RATHER THAN REPRESENTING EXTREME EFFECTS OF DEVELOPMENTAL DISRUPTION AKIN TO TERATOGENESIS. THERE MAY BE ADAPTIVE ADVANTAGE IN A DEVELOPMENTAL CUE INDUCING A PHENOTYPIC CHANGE IN GENERATIONS BEYOND THE IMMEDIATE PREGNANCY, AND A RANGE OF DATA THAT SUPPORT THIS CONCEPT. IN ANIMALS, EPIGENETIC EFFECTS SUCH AS DNA METHYLATION CAN BE PASSED TO SUCCESSIVE GENERATIONS. ENVIRONMENTAL TOXINS, INCLUDING ENDOCRINE DISRUPTORS, MAY INDUCE GREATER RISK OF CHRONIC DISEASE, EVEN AT LOW EXPOSURE LEVELS, IF THEY AFFECT SUCH NORMAL DEVELOPMENTAL EPIGENETIC PROCESSES. APPROPRIATE INTERVENTIONS MAY HAVE LONG-TERM MULTIGENERATIONAL EFFECTS TO REDUCE THE RISK OF CHRONIC DISEASE. 2008 11 4125 32 MECHANISMS OF DISEASE: IN UTERO PROGRAMMING IN THE PATHOGENESIS OF HYPERTENSION. NUTRITIONAL AND OTHER ENVIRONMENTAL CUES DURING DEVELOPMENT CAN PERMANENTLY ALTER THE STRUCTURE, HOMEOSTATIC SYSTEMS, AND FUNCTIONS OF THE BODY. THIS PHENOMENON HAS BEEN REFERRED TO AS 'PROGRAMMING'. EPIDEMIOLOGICAL AND ANIMAL STUDIES SHOW THAT PROGRAMMED EFFECTS OPERATE WITHIN THE NORMAL RANGE OF GROWTH AND DEVELOPMENT, AND INFLUENCE THE RISK OF CHRONIC DISEASE IN ADULT LIFE. WE REVIEW THE EVIDENCE THAT THESE EFFECTS INCLUDE REDUCED NEPHRON NUMBER AND COMPENSATORY ADAPTATIONS, WHICH MIGHT LEAD TO HYPERTENSION, AND PERHAPS ACCELERATE THE DECLINE IN RENAL FUNCTION THAT ACCOMPANIES AGING. THESE PROCESSES MIGHT BE EXACERBATED BY PROGRAMMED CHANGES IN VASCULAR STRUCTURE AND FUNCTION, AND ALTERATIONS IN ENDOCRINE AND METABOLIC HOMEOSTASIS. PROGRAMMED EFFECTS MIGHT BE INITIATED AS EARLY AS THE PERICONCEPTUAL PHASE OF DEVELOPMENT, AND COULD INVOLVE EPIGENETIC CHANGES IN GENE EXPRESSION OR ALTERED STEM CELL ALLOCATION. BETTER UNDERSTANDING OF THESE PROCESSES COULD LEAD TO THE DEVELOPMENT OF NOVEL DIAGNOSTIC AND PREVENTIVE MEASURES, AND TO EARLY DETECTION OF AT-RISK INDIVIDUALS. BY MONITORING BLOOD PRESSURE, WEIGHT, AND RENAL FUNCTION IN CHILDREN, IT MIGHT BE POSSIBLE TO REDUCE THE RISK OF CARDIOVASCULAR AND RENAL DISEASE IN LATER LIFE. 2006 12 2499 25 EPIGENETICS AND EXERCISE. EPIGENETICS CAN BE DEFINED AS 'THE STRUCTURAL ADAPTATION OF CHROMOSOMAL REGIONS SO AS TO REGISTER, SIGNAL, OR PERPETUATE ALTERED ACTIVITY STATES.' INCREASED TRANSCRIPTION OF KEY REGULATORY, METABOLIC, AND MYOGENIC GENES IS AN EARLY RESPONSE TO EXERCISE AND IS IMPORTANT IN MEDIATING SUBSEQUENT ADAPTATIONS IN SKELETAL MUSCLE. DNA HYPOMETHYLATION AND HISTONE HYPERACETYLATION ARE EMERGING AS IMPORTANT CRUCIAL EVENTS FOR INCREASED TRANSCRIPTION. THE COMPLEX INTERACTIONS BETWEEN MULTIPLE EPIGENETIC MODIFICATIONS AND THEIR REGULATION BY METABOLIC CHANGES AND SIGNALING EVENTS DURING EXERCISE, WITH IMPLICATIONS FOR ENHANCED UNDERSTANDING OF THE ACUTE AND CHRONIC ADAPTATIONS TO EXERCISE, ARE QUESTIONS FOR FURTHER INVESTIGATION. 2019 13 2614 34 EPIGENETICS: NEW QUESTIONS ON THE RESPONSE TO HYPOXIA. REDUCTION IN OXYGEN LEVELS BELOW NORMAL CONCENTRATIONS PLAYS IMPORTANT ROLES IN DIFFERENT NORMAL AND PATHOLOGICAL CONDITIONS, SUCH AS DEVELOPMENT, TUMORIGENESIS, CHRONIC KIDNEY DISEASE AND STROKE. ORGANISMS EXPOSED TO HYPOXIA TRIGGER CHANGES AT BOTH CELLULAR AND SYSTEMIC LEVELS TO RECOVER OXYGEN HOMEOSTASIS. MOST OF THESE PROCESSES ARE MEDIATED BY HYPOXIA INDUCIBLE FACTORS, HIFS, A FAMILY OF TRANSCRIPTION FACTORS THAT DIRECTLY INDUCE THE EXPRESSION OF SEVERAL HUNDRED GENES IN MAMMALIAN CELLS. ALTHOUGH DIFFERENT ASPECTS OF HIF REGULATION ARE WELL KNOWN, IT IS STILL UNCLEAR BY WHICH PRECISE MECHANISM HIFS ACTIVATE TRANSCRIPTION OF THEIR TARGET GENES. CONCOMITANTLY, HYPOXIA PROVOKES A DRAMATIC DECREASE OF GENERAL TRANSCRIPTION THAT SEEMS TO RELY IN PART ON EPIGENETIC CHANGES THROUGH A POORLY UNDERSTOOD MECHANISM. IN THIS REVIEW WE DISCUSS THE CURRENT KNOWLEDGE ON CHROMATIN CHANGES INVOLVED IN HIF DEPENDENT GENE ACTIVATION, AS WELL AS ON OTHER EPIGENETIC CHANGES, NOT NECESSARILY LINKED TO HIF THAT TAKE PLACE UNDER HYPOXIC CONDITIONS. 2011 14 6183 37 THE IMPACT OF ENVIRONMENTAL FACTORS IN INFLUENCING EPIGENETICS RELATED TO OXIDATIVE STATES IN THE CARDIOVASCULAR SYSTEM. OXIDATIVE STATES EXERT A SIGNIFICANT INFLUENCE ON A WIDE RANGE OF BIOLOGICAL AND MOLECULAR PROCESSES AND FUNCTIONS. WHEN THEIR BALANCE IS SHIFTED TOWARDS ENHANCED AMOUNTS OF FREE RADICALS, PATHOLOGICAL PHENOMENA CAN OCCUR, AS THE GENERATION OF REACTIVE OXYGEN SPECIES (ROS) IN TISSUE MICROENVIRONMENT OR IN THE SYSTEMIC CIRCULATION CAN BE DETRIMENTAL. EPIDEMIC CHRONIC DISEASES OF WESTERN SOCIETIES, SUCH AS CARDIOVASCULAR DISEASE, OBESITY, AND DIABETES CORRELATE WITH THE IMBALANCE OF REDOX HOMEOSTASIS. CURRENT ADVANCES IN OUR UNDERSTANDING OF EPIGENETICS HAVE REVEALED A PARALLEL SCENARIO SHOWING THE INFLUENCE OF OXIDATIVE STRESS AS A MAJOR REGULATOR OF EPIGENETIC GENE REGULATION VIA MODIFICATION OF DNA METHYLATION, HISTONES, AND MICRORNAS. THIS HAS PROVIDED BOTH THE BIOLOGICAL LINK AND A POTENTIAL MOLECULAR EXPLANATION BETWEEN OXIDATIVE STRESS AND CARDIOVASCULAR/METABOLIC PHENOMENA. ACCORDINGLY, IN THIS REVIEW, WE WILL PROVIDE CURRENT INSIGHTS ON THE PHYSIOLOGICAL AND PATHOLOGICAL IMPACT OF CHANGES IN OXIDATIVE STATES ON CARDIOVASCULAR DISORDERS, BY SPECIFICALLY FOCUSING ON THE INFLUENCE OF EPIGENETIC REGULATION. A SPECIAL EMPHASIS WILL HIGHLIGHT THE EFFECT ON EPIGENETIC REGULATION OF HUMAN'S CURRENT LIFE HABITS, EXTERNAL AND ENVIRONMENTAL FACTORS, INCLUDING FOOD INTAKE, TOBACCO, AIR POLLUTION, AND ANTIOXIDANT-BASED APPROACHES. ADDITIONALLY, THE STRATEGY TO QUANTIFY OXIDATIVE STATES IN HUMANS IN ORDER TO DETERMINE WHICH BIOLOGICAL MARKER COULD BEST MATCH A SUBJECT'S PROFILE WILL BE DISCUSSED. 2017 15 2346 31 EPIGENETIC REGULATION OF METABOLISM AND INFLAMMATION BY CALORIE RESTRICTION. CHRONIC CALORIC RESTRICTION (CR) WITHOUT MALNUTRITION IS KNOWN TO AFFECT DIFFERENT CELLULAR PROCESSES SUCH AS STEM CELL FUNCTION, CELL SENESCENCE, INFLAMMATION, AND METABOLISM. DESPITE THE DIFFERENCES IN THE IMPLEMENTATION OF CR, THE REDUCTION OF CALORIES PRODUCES A WIDESPREAD BENEFICIAL EFFECT IN NONCOMMUNICABLE CHRONIC DISEASES, WHICH CAN BE EXPLAINED BY IMPROVEMENTS IN IMMUNO-METABOLIC ADAPTATION. CELLULAR ADAPTATION THAT OCCURS IN RESPONSE TO DIETARY PATTERNS CAN BE EXPLAINED BY ALTERATIONS IN EPIGENETIC MECHANISMS SUCH AS DNA METHYLATION, HISTONE MODIFICATIONS, AND MICRORNA. IN THIS REVIEW, WE DEFINE THESE MODIFICATIONS AND SYSTEMATICALLY SUMMARIZE THE CURRENT EVIDENCE RELATED TO CR AND THE EPIGENOME. WE THEN EXPLAIN THE SIGNIFICANCE OF GENOME-WIDE EPIGENETIC MODIFICATIONS IN THE CONTEXT OF DISEASE DEVELOPMENT. ALTHOUGH SUBSTANTIAL EVIDENCE EXISTS FOR THE WIDESPREAD EFFECT OF CR ON LONGEVITY, THERE IS NO CONSENSUS REGARDING THE EPIGENETIC REGULATIONS OF THE UNDERLYING CELLULAR MECHANISMS THAT LEAD TO IMPROVED HEALTH. WE PROVIDE COMPELLING EVIDENCE THAT CR PRODUCES LONG-LASTING EPIGENETIC EFFECTS THAT MEDIATE EXPRESSION OF GENES RELATED TO IMMUNO-METABOLIC PROCESSES. EPIGENETIC REPROGRAMMING OF THE UNDERLYING CHRONIC LOW-GRADE INFLAMMATION BY CR CAN LEAD TO IMMUNO-METABOLIC ADAPTATIONS THAT ENHANCE QUALITY OF LIFE, EXTEND LIFESPAN, AND DELAY CHRONIC DISEASE ONSET. 2019 16 5471 29 RESPIRATORY MUSCLE SENESCENCE IN AGEING AND CHRONIC LUNG DISEASES. AGEING IS A PROGRESSIVE CONDITION THAT USUALLY LEADS TO THE LOSS OF PHYSIOLOGICAL PROPERTIES. THIS PROCESS IS ALSO PRESENT IN RESPIRATORY MUSCLES, WHICH ARE AFFECTED BY BOTH SENESCENT CHANGES OCCURRING IN THE WHOLE ORGANISM AND THOSE THAT ARE MORE SPECIFIC FOR MUSCLES. THE MECHANISMS OF THE LATTER CHANGES INCLUDE OXIDATIVE STRESS, DECREASE IN NEUROTROPHIC FACTORS AND DNA ABNORMALITIES. AGEING NORMALLY COEXISTS WITH COMORBIDITIES, INCLUDING RESPIRATORY DISEASES, WHICH FURTHER DETERIORATE THE STRUCTURE AND FUNCTION OF RESPIRATORY MUSCLES. IN THIS CONTEXT, CHANGES INTRINSIC TO AGEING BECOME ENHANCED BY MORE SPECIFIC FACTORS SUCH AS THE IMPAIRMENT IN LUNG MECHANICS AND GAS EXCHANGE, EXACERBATIONS AND HYPOXIA. HYPOXIA IN PARTICULAR HAS A DIRECT EFFECT ON MUSCLES, MAINLY THROUGH THE EXPRESSION OF INDUCIBLE FACTORS (HYPOXIC-INDUCIBLE FACTOR), AND CAN RESULT IN OXIDATIVE STRESS AND CHANGES IN DNA, DECREASE IN MITOCHONDRIAL BIOGENESIS AND DEFECTS IN THE TISSUE REPAIR MECHANISMS. INTENSE EXERCISE CAN ALSO CAUSE DAMAGE IN RESPIRATORY MUSCLES OF ELDERLY RESPIRATORY PATIENTS, BUT THIS CAN BE FOLLOWED BY TISSUE REPAIR AND REMODELLING. HOWEVER, AGEING INTERFERES WITH MUSCLE REPAIR BY TAMPERING WITH THE FUNCTION OF SATELLITE CELLS, MAINLY DUE TO OXIDATIVE STRESS, DNA DAMAGE AND EPIGENETIC MECHANISMS. IN ADDITION TO THE NORMAL PROCESS OF AGEING, STRESS-INDUCED PREMATURE SENESCENCE CAN ALSO OCCUR, INVOLVING CHANGES IN THE EXPRESSION OF MULTIPLE GENES BUT WITHOUT MODIFICATIONS IN TELOMERE LENGTH. 2020 17 6257 30 THE MOLECULAR BASIS OF TOLERANCE. TOLERANCE IS DEFINED AS THE DIMINISHED RESPONSE TO ALCOHOL OR OTHER DRUGS OVER THE COURSE OF REPEATED OR PROLONGED EXPOSURE. THIS MECHANISM ALLOWS PHYSIOLOGICAL PROCESSES TO ACHIEVE STABILITY IN A CONSTANTLY CHANGING ENVIRONMENT. THE ONSET OF TOLERANCE MAY OCCUR WITHIN MINUTES, DURING A SINGLE EXPOSURE TO ALCOHOL (I.E., ACUTE TOLERANCE), OR OVER LONGER TIMEFRAMES AND WITH PROLONGED EXPOSURE TO ALCOHOL (I.E., RAPID OR CHRONIC TOLERANCE). CHANGES IN TOLERANCE INDUCED BY ALCOHOL MAY AFFECT SEVERAL PROCESSES AT THE MOLECULAR, CELLULAR, OR BEHAVIORAL LEVEL. THESE EFFECTS OFTEN ARE INTERRELATED AND MAY BE DIFFICULT TO SEPARATE. THIS ARTICLE DESCRIBES CHANGES AT THE MOLECULAR LEVEL THAT ARE RELATED TO THE ONSET OF ACUTE, RAPID, OR CHRONIC TOLERANCE. IT FOCUSES ON NEURONAL MEMBRANE-BOUND CHANNELS AND THE FACTORS THAT AFFECT THEIR FUNCTION AND PRODUCTION, SUCH AS MODIFICATION OF PROTEIN SYNTHESIS AND ACTIVITY, INTERACTION WITH THE MEMBRANE LIPID MICROENVIRONMENT, EPIGENETIC EFFECTS ON CYTOPLASMIC REGULATION, AND GENE TRANSCRIPTION. ALSO CONSIDERED IS THE GENETICS OF TOLERANCE. 2008 18 4542 25 MURINE MODELS OF SLEEP APNEA: FUNCTIONAL IMPLICATIONS OF ALTERED MACROPHAGE POLARITY AND EPIGENETIC MODIFICATIONS IN ADIPOSE AND VASCULAR TISSUES. OBSTRUCTIVE SLEEP APNEA (OSA) IS A HIGHLY PREVALENT DISEASE ACROSS THE LIFESPAN, IS CHARACTERIZED BY CHRONIC INTERMITTENT HYPOXIA AND SLEEP FRAGMENTATION, AND HAS BEEN INDEPENDENTLY ASSOCIATED WITH SUBSTANTIAL CARDIOMETABOLIC MORBIDITY. HOWEVER, THE REVERSIBILITY OF END-ORGAN MORBIDITY WITH TREATMENT IS NOT ALWAYS APPARENT, SUGGESTING THAT BOTH TISSUE REMODELING AND EPIGENETIC MECHANISMS MAY BE OPERATIONALLY INVOLVED. HERE, WE REVIEW THE CUMULATIVE EVIDENCE FOCUSED AROUND MURINE MODELS OF OSA TO ILLUSTRATE THE TEMPORAL DEPENDENCIES OF CARDIOMETABOLIC DYSFUNCTION AND ITS REVERSIBILITY, AND MORE PARTICULARLY TO DISCUSS THE CRITICAL CONTRIBUTIONS OF TISSUE MACROPHAGES TO ADIPOSE TISSUE INSULIN RESISTANCE AND VASCULAR ATHEROGENESIS. IN ADDITION, WE DESCRIBE INITIAL FINDINGS POTENTIALLY IMPLICATING EPIGENETIC ALTERATIONS IN BOTH THE EMERGENCE OF THE CARDIOMETABOLIC MORBIDITY OF OSA, AND IN ITS REVERSIBILITY WITH TREATMENT. WE ANTICIPATE THAT IMPROVED UNDERSTANDING OF MACROPHAGE BIOLOGY AND EPIGENETICS IN THE CONTEXT OF INTERMITTENT HYPOXIA AND SLEEP FRAGMENTATION WILL LEAD TO DISCOVERY OF NOVEL THERAPEUTIC TARGETS AND IMPROVED CARDIOVASCULAR AND METABOLIC OUTCOMES IN OSA. 2018 19 5252 27 PROGRAMMING AND REGULATION OF METABOLIC HOMEOSTASIS. EVIDENCE IS PRESENTED THAT THE RATE AND EQUILIBRIUM CONSTANTS IN MITOCHONDRIAL OXIDATIVE PHOSPHORYLATION SET AND MAINTAIN METABOLIC HOMEOSTASIS IN EUKARYOTIC CELLS. THESE INTERNAL CONSTANTS DETERMINE THE ENERGY STATE ([ATP]/[ADP][PI]), AND THE ENERGY STATE MAINTAINS HOMEOSTASIS THROUGH A BIDIRECTIONAL SENSORY/SIGNALING CONTROL NETWORK THAT REACHES EVERY ASPECT OF CELLULAR METABOLISM. THE ENERGY STATE IS MAINTAINED WITH HIGH PRECISION (TO APPROXIMATELY 1 PART IN 10(10)), AND THE CONTROL SYSTEM CAN RESPOND TO TRANSIENT CHANGES IN ENERGY DEMAND (ATP UTILIZATION) OF MORE THAN 100 TIMES THE RESTING RATE. EPIGENETIC AND ENVIRONMENTAL FACTORS ARE ABLE TO "FINE-TUNE" THE PROGRAMMED SET POINT OVER A NARROW RANGE TO MEET THE SPECIAL NEEDS ASSOCIATED WITH CELL DIFFERENTIATION AND CHRONIC CHANGES IN METABOLIC REQUIREMENTS. THE RESULT IS ROBUST ACROSS-PLATFORM CONTROL OF METABOLISM, WHICH IS ESSENTIAL TO CELLULAR DIFFERENTIATION AND THE EVOLUTION OF COMPLEX ORGANISMS. A MODEL OF OXIDATIVE PHOSPHORYLATION IS PRESENTED, FOR WHICH THE STEADY-STATE RATE EXPRESSION HAS BEEN DERIVED AND COMPUTER PROGRAMMED. THE BEHAVIOR OF OXIDATIVE PHOSPHORYLATION PREDICTED BY THE MODEL IS SHOWN TO FIT THE EXPERIMENTAL DATA AVAILABLE FOR ISOLATED MITOCHONDRIA AS WELL AS FOR CELLS AND TISSUES. THIS INCLUDES MEASUREMENTS FROM SEVERAL DIFFERENT MAMMALIAN TISSUES AS WELL AS FROM INSECT FLIGHT MUSCLE AND PLANTS. THE RESPIRATORY CHAIN AND OXIDATIVE PHOSPHORYLATION IS REMARKABLY SIMILAR FOR ALL HIGHER PLANTS AND ANIMALS. THIS IS CONSISTENT WITH THE EFFICIENT SYNTHESIS OF ATP AND PRECISE CONTROL OF METABOLIC HOMEOSTASIS PROVIDED BY OXIDATIVE PHOSPHORYLATION BEING A KEY TO CELLULAR DIFFERENTIATION AND THE EVOLUTION OF STRUCTURES WITH SPECIALIZED FUNCTION. 2015 20 231 34 ADAPTIVE CARDIORESPIRATORY CHANGES TO CHRONIC CONTINUOUS AND INTERMITTENT HYPOXIA. THIS CHAPTER REVIEWS CARDIORESPIRATORY ADAPTATIONS TO CHRONIC HYPOXIA (CH) EXPERIENCED AT HIGH ALTITUDE AND CARDIORESPIRATORY PATHOLOGIES ELICITED BY CHRONIC INTERMITTENT HYPOXIA (CIH) OCCURRING WITH OBSTRUCTIVE SLEEP APNEA (OSA). SHORT-TERM CH INCREASES BREATHING (VENTILATORY ACCLIMATIZATION TO HYPOXIA) AND BLOOD PRESSURE (BP) THROUGH CAROTID BODY (CB) CHEMO REFLEX. HYPERPLASIA OF GLOMUS CELLS, ALTERATIONS IN ION CHANNELS, AND RECRUITMENT OF ADDITIONAL EXCITATORY MOLECULES ARE IMPLICATED IN THE HEIGHTENED CB CHEMO REFLEX BY CH. TRANSCRIPTIONAL ACTIVATION OF HYPOXIA-INDUCIBLE FACTORS (HIF-1 AND 2) IS A MAJOR MOLECULAR MECHANISM UNDERLYING RESPIRATORY ADAPTATIONS TO SHORT-TERM CH. HIGH-ALTITUDE NATIVES EXPERIENCING LONG-TERM CH EXHIBIT BLUNTED HYPOXIC VENTILATORY RESPONSE (HVR) AND REDUCED BP DUE TO DESENSITIZATION OF CB RESPONSE TO HYPOXIA AND IMPAIRED PROCESSING OF CB SENSORY INFORMATION AT THE CENTRAL NERVOUS SYSTEM. VENTILATORY CHANGES EVOKED BY LONG-TERM CH ARE NOT READILY REVERSED AFTER RETURN TO SEA LEVEL. OSA PATIENTS AND RODENTS SUBJECTED TO CIH EXHIBIT HEIGHTENED CB CHEMO REFLEX, INCREASED HYPOXIC VENTILATORY RESPONSE, AND HYPERTENSION. INCREASED GENERATION OF REACTIVE OXYGEN SPECIES (ROS) IS A MAJOR CELLULAR MECHANISM UNDERLYING CIH-INDUCED ENHANCED CB CHEMO REFLEX AND THE ENSUING CARDIORESPIRATORY PATHOLOGIES. ROS GENERATION BY CIH IS MEDIATED BY NONTRANSCRIPTIONAL, DISRUPTED HIF-1 AND HIF-2-DEPENDENT TRANSCRIPTIONS AS WELL AS EPIGENETIC MECHANISMS. 2022