1 4543 150 MUSCLE DYSFUNCTION IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE: UPDATE ON CAUSES AND BIOLOGICAL FINDINGS. RESPIRATORY AND/OR LIMB MUSCLE DYSFUNCTION, WHICH ARE FREQUENTLY OBSERVED IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) PATIENTS, CONTRIBUTE TO THEIR DISEASE PROGNOSIS IRRESPECTIVE OF THE LUNG FUNCTION. MUSCLE DYSFUNCTION IS CAUSED BY THE INTERACTION OF LOCAL AND SYSTEMIC FACTORS. THE KEY DELETERIOUS ETIOLOGIC FACTORS ARE PULMONARY HYPERINFLATION FOR THE RESPIRATORY MUSCLES AND DECONDITIONING SECONDARY TO REDUCED PHYSICAL ACTIVITY FOR LIMB MUSCLES. NONETHELESS, CIGARETTE SMOKE, SYSTEMIC INFLAMMATION, NUTRITIONAL ABNORMALITIES, EXERCISE, EXACERBATIONS, ANABOLIC INSUFFICIENCY, DRUGS AND COMORBIDITIES ALSO SEEM TO PLAY A RELEVANT ROLE. ALL THESE FACTORS MODIFY THE PHENOTYPE OF THE MUSCLES, THROUGH THE INDUCTION OF SEVERAL BIOLOGICAL PHENOMENA IN PATIENTS WITH COPD. WHILE RESPIRATORY MUSCLES IMPROVE THEIR AEROBIC PHENOTYPE (PERCENTAGE OF OXIDATIVE FIBERS, CAPILLARIZATION, MITOCHONDRIAL DENSITY, ENZYME ACTIVITY IN THE AEROBIC PATHWAYS, ETC.), LIMB MUSCLES EXHIBIT THE OPPOSITE PHENOTYPE. IN ADDITION, BOTH MUSCLE GROUPS SHOW OXIDATIVE STRESS, SIGNS OF DAMAGE AND EPIGENETIC CHANGES. HOWEVER, FIBER ATROPHY, INCREASED NUMBER OF INFLAMMATORY CELLS, ALTERED REGENERATIVE CAPACITY; SIGNS OF APOPTOSIS AND AUTOPHAGY, AND AN IMBALANCE BETWEEN PROTEIN SYNTHESIS AND BREAKDOWN ARE RATHER CHARACTERISTIC FEATURES OF THE LIMB MUSCLES, MOSTLY IN PATIENTS WITH REDUCED BODY WEIGHT. DESPITE THAT SIGNIFICANT PROGRESS HAS BEEN ACHIEVED IN THE LAST DECADES, FULL ELUCIDATION OF THE SPECIFIC ROLES OF THE TARGET BIOLOGICAL MECHANISMS INVOLVED IN COPD MUSCLE DYSFUNCTION IS STILL REQUIRED. SUCH AN ACHIEVEMENT WILL BE CRUCIAL TO ADEQUATELY TACKLE WITH THIS RELEVANT CLINICAL PROBLEM OF COPD PATIENTS IN THE NEAR-FUTURE. 2015 2 4410 49 MOLECULAR AND BIOLOGICAL PATHWAYS OF SKELETAL MUSCLE DYSFUNCTION IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE. CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) WILL BE A MAJOR LEADING CAUSE OF DEATH WORLDWIDE IN THE NEAR FUTURE. WEAKNESS AND ATROPHY OF THE QUADRICEPS ARE ASSOCIATED WITH A SIGNIFICANTLY POORER PROGNOSIS AND INCREASED MORTALITY IN COPD. DESPITE THAT SKELETAL MUSCLE DYSFUNCTION MAY AFFECT BOTH RESPIRATORY AND LIMB MUSCLE GROUPS IN COPD, THE LATTER ARE FREQUENTLY MORE SEVERELY AFFECTED. THEREFORE, MUSCLE DYSFUNCTION IN COPD IS A COMMON SYSTEMIC MANIFESTATION THAT SHOULD BE EVALUATED ON ROUTINE BASIS IN CLINICAL SETTINGS. IN THE PRESENT REVIEW, SEVERAL ASPECTS OF COPD MUSCLE DYSFUNCTION ARE BEING REVIEWED, WITH SPECIAL EMPHASIS ON THE UNDERLYING BIOLOGICAL MECHANISMS. FIGURES ON THE PREVALENCE OF COPD MUSCLE DYSFUNCTION AND THE MOST RELEVANT ETIOLOGIC CONTRIBUTORS ARE ALSO PROVIDED. DESPITE THAT ONGOING RESEARCH WILL SHED LIGHT INTO THE CONTRIBUTION OF ADDITIONAL MECHANISMS TO COPD MUSCLE DYSFUNCTION, CURRENT KNOWLEDGE POINTS TOWARD THE INVOLVEMENT OF A WIDE SPECTRUM OF CELLULAR AND MOLECULAR EVENTS THAT ARE DIFFERENTIALLY EXPRESSED IN RESPIRATORY AND LIMB MUSCLES. SUCH MECHANISMS ARE THOROUGHLY DESCRIBED IN THE ARTICLE. THE CONTRIBUTION OF EPIGENETIC EVENTS ON COPD MUSCLE DYSFUNCTION IS ALSO REVIEWED. WE CONCLUDE THAT IN VIEW OF THE LATEST DISCOVERIES, FROM NOW, ON NEW AVENUES OF RESEARCH SHOULD BE DESIGNED TO SPECIFICALLY TARGET CELLULAR MECHANISMS AND PATHWAYS THAT IMPAIR MUSCLE MASS AND FUNCTION IN COPD USING PHARMACOLOGICAL STRATEGIES AND/OR EXERCISE TRAINING MODALITIES. 2016 3 2505 50 EPIGENETICS AND MUSCLE DYSFUNCTION IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE. CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) IS A COMMON, PREVENTABLE, AND TREATABLE DISEASE AND A MAJOR LEADING CAUSE OF MORBIDITY AND MORTALITY WORLDWIDE. IN COPD, COMORBIDITIES, ACUTE EXACERBATIONS, AND SYSTEMIC MANIFESTATIONS NEGATIVELY INFLUENCE DISEASE SEVERITY AND PROGRESSION REGARDLESS OF THE RESPIRATORY CONDITION. SKELETAL MUSCLE DYSFUNCTION, WHICH IS ONE OF THE COMMONEST SYSTEMIC MANIFESTATIONS IN PATIENTS WITH COPD, HAS A TREMENDOUS IMPACT ON THEIR EXERCISE CAPACITY AND QUALITY OF LIFE. SEVERAL PATHOPHYSIOLOGICAL AND MOLECULAR UNDERLYING MECHANISMS INCLUDING EPIGENETICS (THE PROCESS WHEREBY GENE EXPRESSION IS REGULATED BY HERITABLE MECHANISMS THAT DO NOT AFFECT DNA SEQUENCE) HAVE BEEN SHOWN TO PARTICIPATE IN THE ETIOLOGY OF COPD MUSCLE DYSFUNCTION. THE EPIGENETIC MODIFICATIONS IDENTIFIED SO FAR IN CELLS INCLUDE DNA METHYLATION, HISTONE ACETYLATION AND METHYLATION, AND NONCODING RNAS SUCH AS MICRORNAS. HEREIN, WE FIRST REVIEW THE ROLE OF EPIGENETIC MECHANISMS IN MUSCLE DEVELOPMENT AND ADAPTATION TO ENVIRONMENTAL FACTORS IN SEVERAL MODELS. MOREOVER, THE EPIGENETIC EVENTS REPORTED SO FAR TO BE POTENTIALLY INVOLVED IN MUSCLE DYSFUNCTION AND MASS LOSS OF PATIENTS WITH COPD ARE ALSO DISCUSSED. FURTHERMORE, THE DIFFERENT EXPRESSION PROFILE OF SEVERAL MUSCLE-ENRICHED MICRORNAS IN THE DIAPHRAGM AND VASTUS LATERALIS MUSCLES OF PATIENTS WITH COPD ARE ALSO REVIEWED FROM RESULTS RECENTLY OBTAINED IN OUR GROUP. THE ROLE OF PROTEIN HYPERACETYLATION IN ENHANCED MUSCLE PROTEIN CATABOLISM OF LIMB MUSCLES IS ALSO DISCUSSED. FUTURE RESEARCH SHOULD FOCUS ON THE FULL ELUCIDATION OF THE TRIGGERS OF EPIGENETIC MECHANISMS AND THEIR SPECIFIC DOWNSTREAM BIOLOGICAL PATHWAYS IN COPD MUSCLE DYSFUNCTION AND WASTING. 2015 4 2348 45 EPIGENETIC REGULATION OF MUSCLE PHENOTYPE AND ADAPTATION: A POTENTIAL ROLE IN COPD MUSCLE DYSFUNCTION. QUADRICEPS MUSCLE DYSFUNCTION OCCURS IN ONE-THIRD OF PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) IN VERY EARLY STAGES OF THEIR CONDITION, EVEN PRIOR TO THE DEVELOPMENT OF AIRWAY OBSTRUCTION. AMONG SEVERAL FACTORS, DECONDITIONING AND MUSCLE MASS LOSS ARE THE MOST RELEVANT CONTRIBUTING FACTORS LEADING TO THIS DYSFUNCTION. MOREOVER, EPIGENETICS, DEFINED AS THE PROCESS WHEREBY GENE EXPRESSION IS REGULATED BY HERITABLE MECHANISMS THAT DO NOT AFFECT DNA SEQUENCE, COULD BE INVOLVED IN THE SUSCEPTIBILITY TO MUSCLE DYSFUNCTION, PATHOGENESIS, AND PROGRESSION. HEREIN, WE REVIEW THE ROLE OF EPIGENETIC MECHANISMS IN MUSCLE DEVELOPMENT AND ADAPTATION TO ENVIRONMENTAL FACTORS SUCH AS IMMOBILIZATION AND EXERCISE, AND THEIR IMPLICATIONS IN THE PATHOPHYSIOLOGY AND SUSCEPTIBILITY TO MUSCLE DYSFUNCTION IN COPD. THE EPIGENETIC MODIFICATIONS IDENTIFIED SO FAR INCLUDE DNA METHYLATION, HISTONE ACETYLATION AND METHYLATION, AND NON-CODING RNAS SUCH AS MICRORNAS (MIRNAS). IN THE PRESENT REVIEW, WE DESCRIBE THE SPECIFIC CONTRIBUTION OF EPIGENETIC MECHANISMS TO THE REGULATION OF EMBRYONIC MYOGENESIS, MUSCLE STRUCTURE AND METABOLISM, IMMOBILIZATION, AND EXERCISE, AND IN MUSCLES OF COPD PATIENTS. EVENTS RELATED TO MUSCLE DEVELOPMENT AND REGENERATION AND THE RESPONSE TO EXERCISE AND IMMOBILIZATION ARE TIGHTLY REGULATED BY EPIGENETIC MECHANISMS. THESE ENVIRONMENTAL FACTORS PLAY A KEY ROLE IN THE OUTCOME OF MUSCLE MASS AND FUNCTION AS WELL AS IN THE SUSCEPTIBILITY TO MUSCLE DYSFUNCTION IN COPD. FUTURE RESEARCH REMAINS TO BE DONE TO SHED LIGHT ON THE SPECIFIC TARGET PATHWAYS OF MIRNA FUNCTION AND OTHER EPIGENETIC MECHANISMS IN THE SUSCEPTIBILITY, PATHOGENESIS, AND PROGRESSION OF COPD MUSCLE DYSFUNCTION. 2013 5 4047 46 MAIN PATHOGENIC MECHANISMS AND RECENT ADVANCES IN COPD PERIPHERAL SKELETAL MUSCLE WASTING. CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) IS A WORLDWIDE PREVALENT RESPIRATORY DISEASE MAINLY CAUSED BY TOBACCO SMOKE EXPOSURE. COPD IS NOW CONSIDERED AS A SYSTEMIC DISEASE WITH SEVERAL COMORBIDITIES. AMONG THEM, SKELETAL MUSCLE DYSFUNCTION AFFECTS AROUND 20% OF COPD PATIENTS AND IS ASSOCIATED WITH HIGHER MORBIDITY AND MORTALITY. ALTHOUGH THE HISTOLOGICAL ALTERATIONS ARE WELL CHARACTERIZED, INCLUDING MYOFIBER ATROPHY, A DECREASED PROPORTION OF SLOW-TWITCH MYOFIBERS, AND A DECREASED CAPILLARIZATION AND OXIDATIVE PHOSPHORYLATION CAPACITY, THE MOLECULAR BASIS FOR MUSCLE ATROPHY IS COMPLEX AND REMAINS PARTLY UNKNOWN. MAJOR DIFFICULTIES LIE IN PATIENT HETEROGENEITY, ACCESSING PATIENTS' SAMPLES, AND COMPLEX MULTIFACTORIAL PROCESS INCLUDING EXTRINSIC MECHANISMS, SUCH AS TOBACCO SMOKE OR DISUSE, AND INTRINSIC MECHANISMS, SUCH AS OXIDATIVE STRESS, HYPOXIA, OR SYSTEMIC INFLAMMATION. MUSCLE WASTING IS ALSO A HIGHLY DYNAMIC PROCESS WHOSE INVESTIGATION IS HAMPERED BY THE DIFFERENTIAL PROTEIN REGULATION ACCORDING TO THE STAGE OF ATROPHY. IN THIS REVIEW, WE REPORT AND DISCUSS RECENT DATA REGARDING THE MOLECULAR ALTERATIONS IN COPD LEADING TO IMPAIRED MUSCLE MASS, INCLUDING INFLAMMATION, HYPOXIA AND HYPERCAPNIA, MITOCHONDRIAL DYSFUNCTION, DIVERSE METABOLIC CHANGES SUCH AS OXIDATIVE AND NITROSATIVE STRESS AND GENETIC AND EPIGENETIC MODIFICATIONS, ALL LEADING TO AN IMPAIRED ANABOLIC/CATABOLIC BALANCE IN THE MYOCYTE. WE RECAPITULATE DATA CONCERNING SKELETAL MUSCLE DYSFUNCTION OBTAINED IN THE DIFFERENT RODENT MODELS OF COPD. FINALLY, WE PROPOSE SEVERAL PATHWAYS THAT SHOULD BE INVESTIGATED IN COPD SKELETAL MUSCLE DYSFUNCTION IN THE FUTURE. 2023 6 5471 45 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 7 1188 41 COPD: A MULTIFACTORIAL SYSTEMIC DISEASE. CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) HAS TRADITIONALLY BEEN CONSIDERED A DISEASE OF THE LUNGS SECONDARY TO CIGARETTE SMOKING AND CHARACTERIZED BY AIRFLOW OBSTRUCTION DUE TO ABNORMALITIES OF BOTH AIRWAY (BRONCHITIS) AND LUNG PARENCHYMA (EMPHYSEMA). IT IS NOW WELL KNOWN THAT COPD IS ASSOCIATED WITH SIGNIFICANT SYSTEMIC ABNORMALITIES, SUCH AS RENAL AND HORMONAL ABNORMALITIES, MALNUTRITION, MUSCLE WASTING, OSTEOPOROSIS, AND ANEMIA. HOWEVER, IT IS STILL UNCLEAR WHETHER THEY REPRESENT CONSEQUENCES OF THE PULMONARY DISORDER, OR WHETHER COPD SHOULD BE CONSIDERED AS A SYSTEMIC DISEASE. THESE SYSTEMIC ABNORMALITIES HAVE BEEN ATTRIBUTED TO AN INCREASED LEVEL OF SYSTEMIC INFLAMMATION. CHRONIC INFLAMMATION, HOWEVER, MAY NOT BE THE ONLY CAUSE OF THE SYSTEMIC EFFECTS OF COPD. RECENT DATA FROM HUMANS AND ANIMAL MODELS SUPPORT THE VIEW THAT EMPHYSEMA MAY BE A VASCULAR DISEASE. OTHER STUDIES HAVE HIGHLIGHTED THE ROLE OF REPAIR FAILURE, BONE MARROW ABNORMALITY, GENETIC AND EPIGENETIC FACTORS, IMMUNOLOGICAL DISORDERS AND INFECTIONS AS POTENTIAL CAUSES OF COPD SYSTEMIC MANIFESTATIONS. BASED ON THIS NEW EVIDENCE, IT IS REASONABLE TO CONSIDER COPD, AND EMPHYSEMA IN PARTICULAR, AS 'A DISEASE WITH A SIGNIFICANT SYSTEMIC COMPONENT' IF NOT A 'SYSTEMIC DISEASE' PER SE. THE AIM OF THIS REVIEW IS TO GIVE AN OVERVIEW OF THE MOST RELEVANT AND INNOVATIVE HYPOTHESIS ABOUT THE EXTRAPULMONARY MANIFESTATIONS OF COPD. 2011 8 6834 38 [IMMUNOPATHOLOGY OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE]. CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) IS A COMMON, PREVENTABLE AND TREATABLE CONDITION THAT HAS A COMPLEX PATHOPHYSIOLOGY AND AN EVEN MORE COMPLEX IMMUNOPATHOLOGICAL PROCESS. THE PURPOSE OF THIS REVIEW WAS TO ANALYZE COPD IMMUNOPATHOLOGICAL ASPECTS, WHICH WAS ADDRESSED BY UNDERTAKING A LITERATURE SEARCH FOR THE MOST RELEVANT DOCUMENTS INDEXED IN THE PUBMED DATABASE OVER THE LAST 10 YEARS. DIFFERENT CONCLUSIONS COULD BE DRAWN: IN COPD IMMUNOPATHOLOGY THERE ARE IMMUNE AND NON-IMMUNE INFLAMMATORY CHANGES WITH OXIDATIVE STRESS IMBALANCE, THERE ARE ALTERATIONS IN THE PROTEASE/ANTI-PROTEASE RATIO CAUSED BY DIRECT AND INDIRECT GENETIC AND EPIGENETIC-ENVIRONMENTAL DEFECTS; COPD PRODUCES IRREVERSIBLE TISSUE DAMAGE AND CHRONIC INFLAMMATION WITH TISSUE REPAIR ALTERATION, WHICH INDUCES CHRONIC OBSTRUCTION OF THE AIRWAY, BRONCHITIS AND SYSTEMIC DAMAGE. MOST COMMON RESULTING COMORBIDITIES INCLUDE CARDIOVASCULAR DISEASE, METABOLIC SYNDROME, OSTEOPOROSIS, DEPRESSION, MUSCULOSKELETAL DYSFUNCTION, INCREASED BIOLOGICAL AGE, LUNG CANCER AND OTHER TYPES OF MALIGNANCIES. IN THE CONCEPTION OF COPD, RECOGNIZING THAT IT IS A NON-TRANSMITTABLE AND PREVENTABLE DISEASE IS INDISPENSABLE. 2017 9 4901 28 OXIDATIVE, INFLAMMATORY, GENETIC, AND EPIGENETIC BIOMARKERS ASSOCIATED WITH CHRONIC OBSTRUCTIVE PULMONARY DISORDER. A LARGE BODY OF EVIDENCE INDICATES THAT CHRONIC OBSTRUCTIVE PULMONARY DISORDER (COPD) IS ACCOMPANIED BY OXIDATIVE STRESS AND INFLAMMATORY AND GENETIC PATHWAYS. EPIDEMIOLOGICAL STUDIES INDICATE THAT COPD IS A MAJOR CAUSE OF MORTALITY AND MORBIDITY IN THE WORLD. RECENT RESEARCH DEVELOPMENT IN COPD FOCUSES ON ACCELERATED AGING AND VARIOUS OXIDATIVE STRESS BIOMARKERS. IT INVOLVES THE CLINICAL MANIFESTATION OF THE DISEASE PROCESS AND MAY ALSO CONTAIN BIOCHEMICAL, IMMUNOLOGICAL, PHYSIOLOGICAL, MORPHOLOGICAL, AND GENETIC ASPECTS THAT ADD TO THE PROGRESSIVENESS OF THE DISEASE. HEREIN, WE SUMMARIZE FINDINGS THAT HIGHLIGHT THE ROLE OF DIMENSIONS OF COPD IN THE INVESTIGATION OF OXIDATIVE STRESS, INFLAMMATORY RESPONSES, GENETIC AND EPIGENETIC STUDIES, AND PHARMACOLOGICAL AND DIETARY ANTIOXIDANT INTERVENTION. 2019 10 288 48 AGING AND INDUCED SENESCENCE AS FACTORS IN THE PATHOGENESIS OF LUNG EMPHYSEMA. CLASSICALLY, THE DEVELOPMENT OF EMPHYSEMA IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE IS BELIEVED TO INVOLVE INFLAMMATION INDUCED BY CIGARETTE SMOKE AND LEUKOCYTE ACTIVATION, INCLUDING OXIDANT-ANTIOXIDANT AND PROTEASE-ANTIPROTEASE IMBALANCES. WHILE THERE IS SUBSTANTIAL EVIDENCE FOR THIS, ADDITIONAL ASPECTS HAVE BEEN SUGGESTED BY A NUMBER OF CLINICAL AND EXPERIMENTAL OBSERVATIONS. SMOKERS EXHIBIT SIGNS OF PREMATURE AGING, PARTICULARLY OBVIOUS IN THE SKIN. THE LINK BETWEEN AGING AND CHRONIC DISEASE IS WELL-KNOWN, E.G., FOR THE BRAIN AND MUSCULOSKELETAL OR CARDIOVASCULAR SYSTEM, AS WELL AS THE CLINICAL LINK BETWEEN MALNUTRITION AND EMPHYSEMA, AND THE EXPERIMENTAL LINK TO CALORIC RESTRICTION. INTERESTINGLY, THIS INTERVENTION ALSO INCREASES LIFESPAN, IN PARALLEL WITH ALTERATIONS IN METABOLISM, OXIDANT BURDEN AND ENDOCRINE SIGNALING. OF SPECIAL INTEREST IS THE OBSERVATION THAT, EVEN IN THE ABSENCE OF AN INFLAMMATORY ENVIRONMENT, LUNG FIBROBLASTS FROM PATIENTS WITH EMPHYSEMA SHOW PERSISTENT ALTERATIONS, POSSIBLY BASED ON EPIGENETIC MECHANISMS. THE IMPORTANCE OF THESE MECHANISMS FOR CELLULAR REPROGRAMMING AND RESPONSE PATTERNS, INDIVIDUAL RISK PROFILE AND THERAPEUTIC OPTIONS IS BECOMING INCREASINGLY RECOGNIZED. THE SAME APPLIES TO CELLULAR SENESCENCE. RECENT FINDINGS FROM PATIENTS AND EXPERIMENTAL MODELS OPEN NOVEL VIEWS INTO THE ARENA OF GENE-ENVIRONMENT INTERACTIONS, INCLUDING THE ROLE OF SYSTEMIC ALTERATIONS, CELLULAR STRESS, TELOMERES, CDK INHIBITORS SUCH AS P16, P21, PRB, PI3K, MTOR, FOXO TRANSCRIPTION FACTORS, HISTONE MODIFICATIONS, AND SIRTUINS. THIS ARTICLE AIMS TO OUTLINE THIS EMERGING PICTURE AND TO STIMULATE THE IDENTIFICATION OF CHALLENGING QUESTIONS. SUCH INSIGHTS ALSO BEAR IMPLICATIONS FOR THE LONG-TERM COURSE OF THE DISEASE IN RELATION TO EXISTING OR FUTURE THERAPIES AND THE EXPLORATION OF POTENTIAL LUNG REGENERATION. 2008 11 971 37 CHRONIC OBSTRUCTIVE PULMONARY DISEASE AND THE HALLMARKS OF AGING. AGING IS CHARACTERIZED BY PROGRESSIVE DETERIORATION OF PHYSIOLOGICAL INTEGRITY, DECLINE IN HOMEOSTASIS, AND DEGENERATION OF THE TISSUES THAT OCCURS AFTER THE REPRODUCTIVE PHASE OF LIFE IS COMPLETE, LEADING TO IMPAIRED FUNCTION. THIS DETERIORATION IS AN IMPORTANT RISK FACTOR FOR CHRONIC LUNG PATHOLOGIES SUCH AS CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). COPD IS A DISEASE THAT DEVELOPS GRADUALLY. EMPHYSEMATOUS CHANGES IN THE LUNG TAKE YEARS TO DEVELOP AFTER EXPOSURE TO CIGARETTE SMOKE; HENCE, THE VAST MAJORITY OF PATIENTS ARE ELDERLY. THERE HAS BEEN A DRAMATIC INCREASE IN THE LIFE EXPECTANCY OF THE GENERAL POPULATION, RESULTING IN AN INCREASED BURDEN OF CHRONIC LUNG DISEASES. THERE IS GROWING EVIDENCE THAT MOLECULAR MECHANISMS INVOLVED IN AGING MAY ALSO PLAY A ROLE IN COPD PATHOGENESIS. RECENTLY, THE NINE HALLMARKS OF AGING WERE IDENTIFIED. IN THIS ARTICLE, WE WILL REVIEW THE NINE HALLMARKS OF AGING AND HOW EACH HALLMARK CONTRIBUTES TO THE PATHOGENESIS OF COPD. 2018 12 4974 32 PATHOPHYSIOLOGICAL MECHANISMS LEADING TO MUSCLE LOSS IN CHRONIC KIDNEY DISEASE. LOSS OF MUSCLE PROTEINS IS A DELETERIOUS CONSEQUENCE OF CHRONIC KIDNEY DISEASE (CKD) THAT CAUSES A DECREASE IN MUSCLE STRENGTH AND FUNCTION, AND CAN LEAD TO A REDUCTION IN QUALITY OF LIFE AND INCREASED RISK OF MORBIDITY AND MORTALITY. THE EFFECTIVENESS OF CURRENT TREATMENT STRATEGIES IN PREVENTING OR REVERSING MUSCLE PROTEIN LOSSES IS LIMITED. THE LIMITATIONS LARGELY STEM FROM THE SYSTEMIC NATURE OF DISEASES SUCH AS CKD, WHICH STIMULATE SKELETAL MUSCLE PROTEIN DEGRADATION PATHWAYS WHILE SIMULTANEOUSLY ACTIVATING MECHANISMS THAT IMPAIR MUSCLE PROTEIN SYNTHESIS AND REPAIR. STIMULI THAT INITIATE MUSCLE PROTEIN LOSS INCLUDE METABOLIC ACIDOSIS, INSULIN AND IGF1 RESISTANCE, CHANGES IN HORMONES, CYTOKINES, INFLAMMATORY PROCESSES AND DECREASED APPETITE. A GROWING BODY OF EVIDENCE SUGGESTS THAT SIGNALLING MOLECULES SECRETED FROM MUSCLE CAN ENTER THE CIRCULATION AND SUBSEQUENTLY INTERACT WITH RECIPIENT ORGANS, INCLUDING THE KIDNEYS, WHILE CONVERSELY, PATHOLOGICAL EVENTS IN THE KIDNEY CAN ADVERSELY INFLUENCE PROTEIN METABOLISM IN SKELETAL MUSCLE, DEMONSTRATING THE EXISTENCE OF CROSSTALK BETWEEN KIDNEY AND MUSCLE. TOGETHER, THESE SIGNALS, WHETHER DIRECT OR INDIRECT, INDUCE CHANGES IN THE LEVELS OF REGULATORY AND EFFECTOR PROTEINS VIA ALTERATIONS IN MRNAS, MICRORNAS AND CHROMATIN EPIGENETIC RESPONSES. ADVANCES IN OUR UNDERSTANDING OF THE SIGNALS AND PROCESSES THAT MEDIATE MUSCLE LOSS IN CKD AND OTHER MUSCLE WASTING CONDITIONS WILL SUPPORT THE FUTURE DEVELOPMENT OF THERAPEUTIC STRATEGIES TO REDUCE MUSCLE LOSS. 2022 13 6880 45 [RESEARCH PROGRESS OF LUNG AGING IN CHRONIC RESPIRATORY DISEASES]. CELL AGING IS AN EXTREMELY COMPLEX PROCESS, WHICH IS CHARACTERIZED BY MITOCHONDRIAL STRUCTURAL DYSFUNCTION, TELOMERE SHORTENING, INFLAMMATORY MICROENVIRONMENT, PROTEIN HOMEOSTASIS IMBALANCE, EPIGENETIC CHANGES, ABNORMAL DNA DAMAGE AND REPAIR, ETC. AGING IS USUALLY ACCOMPANIED BY STRUCTURAL AND FUNCTIONAL DAMAGE OF TISSUES AND ORGANS WHICH FURTHER INDUCES THE OCCURRENCE AND DEVELOPMENT OF AGING-RELATED DISEASES. AGING INCLUDES PHYSIOLOGICAL AGING CAUSED BY INCREASED AGE AND PATHOLOGICAL AGING INDUCED BY A VARIETY OF FACTORS. NOTEWORTHY, AS A TARGET ORGAN DIRECTLY CONTACTING WITH THE OUTSIDE AIR, LUNG IS MORE PRONE TO VARIOUS STIMULI, CAUSING PATHOLOGICAL PREMATURE AGING WHICH IS LUNG AGING. STUDIES HAVE FOUND THAT THERE IS A CERTAIN PROPORTION OF SENESCENT CELLS IN THE LUNGS OF MOST CHRONIC RESPIRATORY DISEASES. HOWEVER, THE UNDERLYING MECHANISM BY WHICH THESE SENESCENT CELLS INDUCE LUNG SENESCENCE AND THEIR ROLE IN CHRONIC RESPIRATORY DISEASES IS STILL OBSCURE. THIS PAPER FOCUSES ON THE CAUSES AND CLASSIFICATION OF LUNG AGING, THE INTERNAL MECHANISM OF LUNG AGING INVOLVED IN CHRONIC RESPIRATORY DISEASES, AND THE APPLICATION OF ANTI-AGING TREATMENTS IN CHRONIC RESPIRATORY DISEASES. WE HOPE TO PROVIDE NEW RESEARCH IDEAS AND THEORETICAL BASIS FOR THE CLINICAL PREVENTION AND TREATMENT IN CHRONIC RESPIRATORY DISEASES. 2022 14 4029 35 LUNGS, BONE MARROW, AND ADIPOSE TISSUE. A NETWORK APPROACH TO THE PATHOBIOLOGY OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE. PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) OFTEN SUFFER OTHER CONCOMITANT DISORDERS, SUCH AS CARDIOVASCULAR DISEASES AND METABOLIC DISORDERS, THAT INFLUENCE SIGNIFICANTLY (AND INDEPENDENTLY OF LUNG FUNCTION) THEIR HEALTH STATUS AND PROGNOSIS. THUS, COPD IS NOT A SINGLE ORGAN CONDITION, AND DISTURBANCES OF A COMPLEX NETWORK OF INTERORGAN CONNECTED RESPONSES OCCUR AND MODULATE THE NATURAL HISTORY OF THE DISEASE. HERE, WE PROPOSE A NOVEL HYPOTHESIS THAT CONSIDERS A VASCULARLY CONNECTED NETWORK WITH (1) THE LUNGS AS THE MAIN EXTERNAL SENSOR OF THE SYSTEM AND A MAJOR SOURCE OF "DANGER SIGNALS"; (2) THE ENDOTHELIUM AS AN INTERNAL SENSOR OF THE SYSTEM (ALSO A POTENTIAL TARGET TISSUE); AND (3) TWO KEY RESPONDING ELEMENTS, BONE MARROW AND ADIPOSE TISSUE, WHICH PRODUCE BOTH INFLAMMATORY AND REPAIR SIGNALS. ACCORDING TO THE MODEL, THE DEVELOPMENT OF COPD, AND ASSOCIATED MULTIMORBIDITIES (HERE WE FOCUS ON CARDIOVASCULAR DISEASE AS AN IMPORTANT EXAMPLE), DEPEND ON THE MANNER IN WHICH THE VASCULAR CONNECTED NETWORK RESPONDS, ADAPTS, OR FAILS TO ADAPT (DICTATED BY THE GENETIC AND EPIGENETIC BACKGROUND OF THE INDIVIDUAL) TO THE INHALATION OF PARTICLES AND GASES, MAINLY IN CIGARETTE SMOKE. THE CAVEATS AND LIMITATIONS OF THE HYPOTHESIS, AS WELL AS THE EXPERIMENTAL AND CLINICAL RESEARCH NEEDED TO TEST AND EXPLORE THE PROPOSED MODEL, ARE ALSO BRIEFLY DISCUSSED. 2013 15 4122 43 MECHANISMS OF DEVELOPMENT OF MULTIMORBIDITY IN THE ELDERLY. IN AGEING POPULATIONS MANY PATIENTS HAVE MULTIPLE DISEASES CHARACTERISED BY ACCELERATION OF THE NORMAL AGEING PROCESS. BETTER UNDERSTANDING OF THE SIGNALLING PATHWAYS AND CELLULAR EVENTS INVOLVED IN AGEING SHOWS THAT THESE ARE CHARACTERISTIC OF MANY CHRONIC DEGENERATIVE DISEASES, SUCH AS CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD), CHRONIC CARDIOVASCULAR AND METABOLIC DISEASES, AND NEURODEGENERATION. COMMON MECHANISMS HAVE NOW BEEN IDENTIFIED IN THESE DISEASES, WHICH SHOW EVIDENCE OF CELLULAR SENESCENCE WITH TELOMERE SHORTENING, ACTIVATION OF PI3K-AKT-MTOR SIGNALLING, IMPAIRED AUTOPHAGY, MITOCHONDRIAL DYSFUNCTION, STEM CELL EXHAUSTION, EPIGENETIC CHANGES, ABNORMAL MICRORNA PROFILES, IMMUNOSENESCENCE AND LOW GRADE CHRONIC INFLAMMATION ("INFLAMMAGING"). MANY OF THESE PATHWAYS ARE DRIVEN BY CHRONIC OXIDATIVE STRESS. THERE IS ALSO A REDUCTION IN ANTI-AGEING MOLECULES, SUCH AS SIRTUINS AND KLOTHO, WHICH FURTHER ACCELERATES THE AGEING PROCESS. UNDERSTANDING THESE MOLECULAR MECHANISMS HAS IDENTIFIED SEVERAL NOVEL THERAPEUTIC TARGETS AND SEVERAL DRUGS HAVE ALREADY BEEN DEVELOPED THAT MAY SLOW THE AGEING PROCESS, AS WELL AS LIFESTYLE INTERVENTIONS, SUCH AS DIET AND PHYSICAL ACTIVITY. THIS INDICATES THAT IN THE FUTURE NEW TREATMENT APPROACHES MAY TARGET THE COMMON PATHWAYS INVOLVED IN MULTIMORBIDITY AND THIS AREA OF RESEARCH SHOULD BE GIVEN HIGH PRIORITY. THUS, COPD SHOULD BE CONSIDERED AS A COMPONENT OF MULTIMORBIDITY AND COMMON DISEASE PATHWAYS, PARTICULARLY ACCELERATED AGEING, SHOULD BE TARGETED. 2015 16 4112 42 MECHANISMS CONTRIBUTING TO THE COMORBIDITY OF COPD AND LUNG CANCER. LUNG CANCER AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) OFTEN CO-OCCUR, AND INDIVIDUALS WITH COPD ARE AT A HIGHER RISK OF DEVELOPING LUNG CANCER. WHILE THE UNDERLYING MECHANISM FOR THIS RISK IS NOT WELL UNDERSTOOD, ITS MAJOR CONTRIBUTING FACTORS HAVE BEEN PROPOSED TO INCLUDE GENOMIC, IMMUNE, AND MICROENVIRONMENT DYSREGULATION. HERE, WE REVIEW THE EVIDENCE AND SIGNIFICANT STUDIES THAT EXPLORE THE MECHANISMS UNDERLYING THE HEIGHTENED LUNG CANCER RISK IN PEOPLE WITH COPD. GENETIC AND EPIGENETIC CHANGES, AS WELL AS THE ABERRANT EXPRESSION OF NON-CODING RNAS, PREDISPOSE THE LUNG EPITHELIUM TO CARCINOGENESIS BY ALTERING THE EXPRESSION OF CANCER- AND IMMUNE-RELATED GENES. OXIDATIVE STRESS GENERATED BY TOBACCO SMOKING PLAYS A ROLE IN REDUCING GENOMIC INTEGRITY, PROMOTING EPITHELIAL-MESENCHYMAL-TRANSITION, AND GENERATING A CHRONIC INFLAMMATORY ENVIRONMENT. THIS LEADS TO ABNORMAL IMMUNE RESPONSES THAT PROMOTE CANCER DEVELOPMENT, THOUGH NOT ALL SMOKERS DEVELOP LUNG CANCER. SEX DIFFERENCES IN THE METABOLISM OF TOBACCO SMOKE PREDISPOSE FEMALES TO DEVELOPING COPD AND ACCUMULATING DAMAGE FROM OXIDATIVE STRESS THAT POSES A RISK FOR THE DEVELOPMENT OF LUNG CANCER. DYSREGULATION OF THE LUNG MICROENVIRONMENT AND MICROBIOME CONTRIBUTES TO CHRONIC INFLAMMATION, WHICH IS OBSERVED IN COPD AND KNOWN TO FACILITATE CANCER INITIATION IN VARIOUS TUMOR TYPES. FURTHER, THERE IS A NEED TO BETTER CHARACTERIZE AND IDENTIFY THE PROPORTION OF INDIVIDUALS WITH COPD WHO ARE AT A HIGH RISK FOR DEVELOPING LUNG CANCER. WE EVALUATE POSSIBLE NOVEL AND INDIVIDUALIZED SCREENING STRATEGIES, INCLUDING BIOMARKERS IDENTIFIED IN GENETIC STUDIES AND EXHALED BREATH CONDENSATE ANALYSIS. WE ALSO DISCUSS THE USE OF CORTICOSTEROIDS AND STATINS AS CHEMOPREVENTIVE AGENTS TO PREVENT LUNG CANCER. IT IS CRUCIAL THAT WE OPTIMIZE THE CURRENT METHODS FOR THE EARLY DETECTION AND MANAGEMENT OF LUNG CANCER AND COPD IN ORDER TO IMPROVE THE HEALTH OUTCOMES FOR A LARGE AFFECTED POPULATION. 2023 17 2859 38 FROM SMOKING TO COPD--CURRENT APPROACHES. CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) REMAINS A LEADING CAUSE OF DEATH ALL OVER THE WORLD. EVEN THOUGH IT IS THE MOST INTENSELY STUDIED DISEASE INDUCED BY CIGARETTE SMOKING THERE ARE STILL INCOMPLETE RESEARCHES CONCERNING ITS PATHOPHYSIOLOGY AND TREATMENT. SO FAR IT HAS BEEN DETERMINED THE DELETERIOUS EFFECTS OF THE SECRETED MOLECULES DIVERSITY AND SOME FEASIBLE THERAPIES FOR THEIR DIMINUTION. ACCORDING TO CURRENT STUDIES MORE RELEVANCE GAINS THE POSSIBLE AUTOIMMUNE ORIGIN OF COPD AND THE EPIGENETIC MODIFICATIONS. THE IDEA OF AUTOIMMUNITY IN SMOKING INDUCED COPD BEGAN TO BE SPECULATED WITH THE DISCOVERY OF AUTOANTIBODIES IN PATIENT'S SERUM, BUT THERE ARE SOME STUDIES WHO CONSIDER ANTIBODY COMPLEXES THAT RESIDE IN THE LUNG TISSUE AS MORE RELEVANT FOR FUTURE RESEARCH. BY DEVELOPING THE AUTOIMMUNE ASPECT OF COPD IT WILL BECOME POSSIBLE TO SELECT MORE PRECISE TREATMENT STRATEGIES. THE IMPORTANCE OF EPIGENETIC CHANGES IN THIS FIELD MIGHT BE APPRECIATED STARTING WITH THE FACT OF AN EXISTING CONNECTION BETWEEN EPIGENETIC MODIFICATIONS INDUCED BY MATERNAL SMOKING AND LATTER COPD DEVELOPMENT. THIS EXPLAINS THE TENDENCY TOWARD DIFFERENT DRUGS CAPABLE OF RESTORING THESE TRANSFORMATIONS SUCH AS DEACETYLATION AGENTS EXPECTED ALSO TO PREVENT STEROID RESISTANCE. NEVERTHELESS SMOKING CESSATION REMAINS AS THE INDISPENSABLE APPROACH FOR COPD TREATMENT AND PREVENTION. 2016 18 4953 46 PATHOGENESIS OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) INDUCED BY CIGARETTE SMOKE. CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) IS A COMMON RESPIRATORY DISEASE THAT IS CHARACTERIZED BY FUNCTIONAL AND STRUCTURAL ALTERATIONS PRIMARILY CAUSED BY LONG-TERM INHALATION OF HARMFUL PARTICLES. CIGARETTE SMOKE (CS) INDUCES AIRWAY INFLAMMATION IN COPD, WHICH IS KNOWN TO PERSIST EVEN AFTER SMOKING CESSATION. THIS REVIEW DISCUSSES THE BASIC PATHOGENESIS OF COPD, WITH PARTICULAR FOCUS ON AN ENDOGENOUS PROTECTIVE MECHANISM AGAINST OXIDATIVE STRESS VIA NRF2, ALTERED IMMUNE RESPONSE OF THE AIRWAY INFLAMMATORY CELLS, EXAGGERATED CELLULAR SENESCENCE OF THE LUNG STRUCTURAL CELLS, AND CELL DEATH WITH EXPANDED INFLAMMATION. RECENTLY, CS-INDUCED MITOCHONDRIA AUTOPHAGY IS REPORTED TO INITIATE PROGRAMMED NECROSIS (NECROPTOSIS). NECROPTOSIS IS A NEW CONCEPT OF CELL DEATH WHICH IS DRIVEN BY A DEFINED MOLECULAR PATHWAY ALONG WITH EXAGGERATED INFLAMMATION. THIS NEW CELL DEATH MECHANISM IS OF IMPORTANCE DUE TO ITS ABILITY TO PRODUCE MORE INFLAMMATORY SUBSTANCES DURING THE PROCESS OF EPITHELIAL DEATH, CONTRIBUTING TO PERSISTENT AIRWAY INFLAMMATION THAT CANNOT BE EXPLAINED BY APOPTOSIS-DERIVED CELL DEATH. AUTOPHAGY IS AN AUTO-CELL COMPONENT DEGRADATION SYSTEM EXECUTED BY LYSOSOMES THAT CONTROLS PROTEIN AND ORGANELLE DEGRADATION FOR SUCCESSFUL HOMEOSTASIS. AS WELL AS IN THE PROCESS OF NECROPTOSIS, AUTOPHAGY IS ALSO OBSERVED DURING CELLULAR SENESCENCE. AGING OF THE LUNGS RESULTS IN THE ACQUISITION OF SENESCENCE-ASSOCIATED SECRETORY PHENOTYPES (SASP) THAT ARE KNOWN TO SECRETE INFLAMMATORY CYTOKINES, CHEMOKINES, GROWTH FACTORS, AND MATRIX METALLOPROTEINASES RESULTING IN CHRONIC LOW-GRADE INFLAMMATION. IN FUTURE RESEARCH, WE INTEND TO HIGHLIGHT THE GENETIC AND EPIGENETIC APPROACHES THAT CAN FACILITATE THE UNDERSTANDING OF DISEASE SUSCEPTIBILITY. THE GOAL OF PRECISION MEDICINE IS TO ESTABLISH MORE ACCURATE DIAGNOSIS AND TREATMENT METHODS BASED ON THE PATIENT-SPECIFIC PATHOGENIC CHARACTERISTICS. THIS REVIEW PROVIDES INSIGHTS INTO CS-INDUCED COPD PATHOGENESIS, WHICH CONTRIBUTES TO A VERY COMPLEX DISEASE. INVESTIGATING THE MECHANISM OF DEVELOPING COPD, ALONG WITH THE AVAILABILITY OF THE PARTICULAR INHIBITORS, WILL LEAD TO NEW THERAPEUTIC APPROACHES IN COPD TREATMENT. 2019 19 4445 35 MOLECULAR LINKS BETWEEN COPD AND LUNG CANCER: NEW TARGETS FOR DRUG DISCOVERY? COPD AND LUNG CANCER ARE LEADING CAUSES OF MORBIDITY AND MORTALITY WORLDWIDE, AND THEY SHARE A COMMON ENVIRONMENTAL RISK FACTOR IN CIGARETTE SMOKE EXPOSURE AND A GENETIC PREDISPOSITION REPRESENTED BY THEIR INCIDENCE IN ONLY A FRACTION OF SMOKERS. THIS REFLECTS THE ABILITY OF CIGARETTE SMOKE TO INDUCE AN INFLAMMATORY RESPONSE IN THE AIRWAYS OF SUSCEPTIBLE SMOKERS. MOREOVER, COPD COULD BE A DRIVING FACTOR IN LUNG CANCER, BY INCREASING OXIDATIVE STRESS AND THE RESULTING DNA DAMAGE AND REPRESSION OF THE DNA REPAIR MECHANISMS, CHRONIC EXPOSURE TO PRO-INFLAMMATORY CYTOKINES, REPRESSION OF INNATE IMMUNITY AND INCREASED CELLULAR PROLIFERATION. AREAS COVERED: WE HAVE FOCUSED OUR REVIEW ON THE POTENTIAL PATHOGENIC MOLECULAR LINKS BETWEEN TOBACCO SMOKING-RELATED COPD AND LUNG CANCER AND THE POTENTIAL MOLECULAR TARGETS FOR NEW DRUG DEVELOPMENT BY UNDERSTANDING THE COMMON SIGNALING PATHWAYS INVOLVED IN COPD AND LUNG CANCER. EXPERT COMMENTARY: RESEARCH IN THIS FIELD IS MOSTLY LIMITED TO ANIMAL MODELS OR SMALL CLINICAL TRIALS. LARGE CLINICAL TRIALS ARE NEEDED BUT MOSTLY COMBINED MODELS OF COPD AND LUNG CANCER ARE NECESSARY TO INVESTIGATE THE PROCESSES CAUSED BY CHRONIC INFLAMMATION, INCLUDING GENETIC AND EPIGENETIC ALTERATION, AND THE EXPRESSION OF INFLAMMATORY MEDIATORS THAT LINK COPD AND LUNG CANCER, TO IDENTIFY NEW MOLECULAR THERAPEUTIC TARGETS. 2019 20 4896 41 OXIDATIVE STRESS IN AIRWAY DISEASES. AIRWAY OXIDATIVE STRESS IS BROADLY DEFINED AS AN IMBALANCE BETWEEN PROOXIDATIVE AND ANTIOXIDATIVE PROCESSES IN THE AIRWAY. GIVEN ITS DIRECT EXPOSURE TO THE ENVIRONMENT, THE LUNG HAS SEVERAL MECHANISMS TO PREVENT AN EXCESSIVE DEGREE OF OXIDATIVE STRESS. BOTH ENZYMATIC AND NONENZYMATIC SYSTEMS CAN BUFFER A WIDE RANGE OF REACTIVE OXIDATIVE SPECIES AND OTHER COMPOUNDS WITH OXIDATIVE POTENTIAL. IN DISEASES LIKE ASTHMA AND CHRONIC OBSTRUCTIVE LUNG DISEASE, AIRWAY OXIDATIVE STRESS CAN OCCUR FROM A NUMBER OF SOURCES, INCLUDING GREATER EXPOSURE TO ENVIRONMENTAL PROOXIDANTS, AIRWAY INFILTRATION OF INFLAMMATORY CELLS, METABOLIC DEREGULATION, AND REDUCED LEVELS OF ANTIOXIDANTS. AIRWAY OXIDATIVE STRESS HAS BEEN ASSOCIATED WITH WORSE DISEASE SEVERITY, REDUCED LUNG FUNCTION, AND EPIGENETIC CHANGES THAT CAN DIMINISH RESPONSE TO STEROIDS. ALTHOUGH OXIDATIVE STRESS HAS BEEN LINKED TO A WIDE RANGE OF ADVERSE BIOLOGICAL EFFECTS, IT HAS ALSO BEEN ASSOCIATED WITH ADAPTIVE RESPONSES AND WITH RESOLUTION OF INFLAMMATION. THEREFORE, MORE THAN BEING AN IMBALANCE WITH A PREDICTABLE THRESHOLD AFTER WHICH DISEASE OR INJURY ENSUES, OXIDATIVE STRESS IS A DYNAMIC AND CONTINUOUS PROCESS. THIS MIGHT EXPLAIN WHY SUPPLEMENTING ANTIOXIDANTS HAS LARGELY FAILED TO IMPROVE DISEASES SUCH AS ASTHMA AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE. HOWEVER, THE THERAPEUTIC POTENTIAL OF ANTIOXIDANTS COULD BE GREATLY IMPROVED BY TAKING AN APPROACH THAT CONSIDERS INDIVIDUAL AND ENVIRONMENTAL RISK FACTORS, INSTEAD OF TREATING OXIDATIVE AIRWAY STRESS BROADLY. 2013