1 6323 129 THE ROLE OF A POTENTIAL BIOMARKER IN PATIENTS WITH MIGRAINE: REVIEW AND NEW INSIGHTS. INTRODUCTION: THE SEARCH FOR AN IDEAL BIOMARKER FOR MIGRAINE HAS PERSISTED FOR A LONG TIME. THERE IS PLENTIFUL EVIDENCE OF POTENTIAL BIOMARKERS FOR MIGRAINE FOUND IN CEREBROSPINAL FLUID, BLOOD, AND SALIVA.AREAS COVERED: HEREIN, THE AUTHORS HIGHLIGHT AND DISCUSS THE MOST PROMISING CANDIDATES IN THE LITERATURE. AN ELECTRONIC SEARCH WAS PERFORMED FOR STUDIES PUBLISHED BETWEEN 2010 AND 2020 IN MEDLINE, PUBMED, AND EMBASE, RELATED TO POTENTIAL BIOMARKERS IN MIGRAINE PATIENTS, FOUND IN CEREBROSPINAL FLUID, SALIVA, AND SERUM, FOCUSING ON BIOMARKERS THAT CAN BE RELATED TO TREATMENT AND CLINICAL OUTCOMES.EXPERT OPINION: AN IDEAL BIOMARKER, OR A PANEL OF BIOMARKERS, COULD REVOLUTIONIZE THE WAY WE ADDRESS AND PROPOSE TREATMENTS FOR THIS DISEASE. ONCE SEVERE PRESENTATIONS AND PHENOTYPES HAVE BEEN IDENTIFIED USING A RELIABLE BIOMARKER, PATIENTS COULD BE TREATED AT EARLIER DISEASE STAGES WITH MORE SPECIFIC MEDICATIONS. THE MOST IMPORTANT BIOMARKERS WITH THE MOST SIGNIFICANT LEVELS OF EVIDENCE COMPRISED CALCITONIN GENE-RELATED PEPTIDE (CGRP), GLUTAMATE, NERVE GROWTH FACTOR, SOME INFLAMMATORY (CRP, TNF-ALPHA, INTERLEUKINS) AND OXIDATIVE STRESS MARKERS. CGRP WAS ASSOCIATED WITH EPISODIC, CHRONIC MIGRAINE AND RESPONSE TO TREATMENT. PITUITARY ADENYLATE CYCLASE-ACTIVATING POLYPEPTIDE IS AN EMERGING NEUROPEPTIDE INVOLVED IN MIGRAINE DIAGNOSTICS AND SEVERITY. NEW GENETIC AND EPIGENETIC BIOMARKERS WILL BE CANDIDATES FOR FUTURE RESEARCH. 2021 2 638 53 BIOMARKERS ASSOCIATED WITH MIGRAINE AND THEIR POTENTIAL ROLE IN MIGRAINE MANAGEMENT. OBJECTIVE: THE FOCUS OF THIS REVIEW IS TO REVIEW POTENTIAL DIAGNOSTIC AND THERAPEUTIC BIOMARKERS ASSOCIATED WITH MIGRAINE. BACKGROUND: MIGRAINE HEADACHE IS A COMMON DISEASE THAT AFFECTS MILLIONS OF INDIVIDUALS WORLDWIDE. ALTHOUGH WELL-ACCEPTED DIAGNOSTIC CRITERIA EXIST FOR MIGRAINE, IT IS STILL A COMPLEX DISORDER THAT REMAINS BOTH UNDERDIAGNOSED AND MISDIAGNOSED. THE CAUSES OF MIGRAINE ARE LIKELY A MIX OF GENETIC, EPIGENETIC, AND ENVIRONMENTAL FACTORS THAT, TOGETHER WITH THE INDIVIDUAL'S LIFE HISTORY, TRANSLATE INTO THE OBSERVED CLINICAL HETEROGENEITY. INHERENT CLINICAL HETEROGENEITY IS AN OBSTACLE IN DEVELOPING MORE EFFECTIVE TREATMENTS. THE LACK OF APPROPRIATE BIOMARKERS IS ALSO AN IMPEDIMENT TO DEVELOPING MORE EFFECTIVE THERAPEUTIC/PREVENTIVE APPROACHES. ULTIMATELY, BIOMARKERS MAY FACILITATE THE GOAL OF INDIVIDUALIZED MEDICINE BY ENABLING CLINICIANS TO MORE ACCURATELY DIAGNOSE AND TREAT MIGRAINE AND OTHER TYPES OF HEADACHE. METHODS: A COMPREHENSIVE REVIEW WAS CONDUCTED OF PUBMED CITATIONS CONTAINING THE KEY WORD "MARKER" OR "BIOMARKER" COMBINED WITH "MIGRAINE" OR "HEADACHE." OTHER KEY WORDS INCLUDED "SERUM," "SALIVA," "CEREBROSPINAL FLUID," "GENES," "BLOOD," AND "INFLAMMATION." THE ONLY RESTRICTION WAS ENGLISH-LANGUAGE PUBLICATION. THE ABSTRACTS OF ALL ARTICLES MEETING THESE CRITERIA WERE REVIEWED, AND FULL TEXT WAS RETRIEVED AND EXAMINED FOR RELEVANT REFERENCES. RESULTS: DATA FROM HUMAN STUDIES HAVE BEGUN TO IDENTIFY GENETIC MUTATIONS/POLYMORPHISMS AND ALTERED LEVELS OF SPECIFIC PROINFLAMMATORY AND NEUROMODULATORY MOLECULES THAT STRONGLY CORRELATE WITH MIGRAINE AS WELL AS SYMPTOM SEVERITY. RESULTS FROM A SMALLER NUMBER OF STUDIES HAVE IDENTIFIED PARAMETERS, SUCH AS THE NEUROPEPTIDE CALCITONIN GENE-RELATED PEPTIDE (CGRP), WHICH ARE SIGNIFICANTLY ASSOCIATED WITH RESPONSE TO SPECIFIC TREATMENTS FOR ACUTE MIGRAINE ATTACKS AND PROPHYLAXIS. EPIGENETIC MECHANISMS MAY ALSO BE INVOLVED IN THE DEVELOPMENT OF MIGRAINE, AND UNDERSTANDING ENVIRONMENTALLY INDUCED GENETIC CHANGES ASSOCIATED WITH THIS DISEASE MAY EVENTUALLY GUIDE THE DEVELOPMENT OF THERAPIES CAPABLE OF REVERSING THESE PATHOPHYSIOLOGICAL CHANGES IN GENE FUNCTION. CONCLUSIONS: THE UNDERSTANDING OF THE ETIOLOGY OF MIGRAINE IS INCOMPLETE. ALTHOUGH THE IDENTIFICATION AND VALIDATION OF BIOMARKERS HAS GREATLY ADVANCED DIAGNOSTIC PRECISION AND MEASURES OF THERAPEUTIC EFFICACY IN OTHER DISEASES, THERE ARE NO CURRENTLY ACCEPTED BIOMARKERS FOR CHRONIC OR EPISODIC MIGRAINE. HOWEVER, THE CONTINUED INVESTIGATION AND IDENTIFICATION OF GENETIC, EPIGENETIC, AND MOLECULAR BIOMARKERS IS LIKELY TO FACILITATE THE GOAL OF INDIVIDUALIZING MEDICINE BY ENABLING CLINICIANS TO MORE ACCURATELY DIAGNOSE AND TREAT MIGRAINE AND OTHER HEADACHE DISORDERS. 2013 3 5038 26 PHARMACOGENETICS OF CHRONIC PAIN AND ITS TREATMENT. THIS PAPER REVIEWS THE IMPACT OF GENETIC VARIABILITY OF DRUG METABOLIZING ENZYMES, TRANSPORTERS, RECEPTORS, AND PATHWAYS INVOLVED IN CHRONIC PAIN PERCEPTION ON THE EFFICACY AND SAFETY OF ANALGESICS AND OTHER DRUGS USED FOR CHRONIC PAIN TREATMENT. SEVERAL CANDIDATE GENES HAVE BEEN IDENTIFIED IN THE LITERATURE, WHILE THERE IS USUALLY ONLY LIMITED CLINICAL EVIDENCE SUBSTANTIATING FOR THE PENETRATION OF THE TESTING FOR THESE CANDIDATE BIOMARKERS INTO THE CLINICAL PRACTICE. FURTHER, THE PAIN-PERCEPTION REGULATION AND MODULATION ARE STILL NOT FULLY UNDERSTOOD, AND THUS MORE COMPLEX KNOWLEDGE OF GENETIC AND EPIGENETIC BACKGROUND FOR ANALGESIA WILL BE NEEDED PRIOR TO THE CLINICAL USE OF THE CANDIDATE GENETIC BIOMARKERS. 2013 4 2029 33 EPIGENETIC CHANGES IN HEADACHE. INTRODUCTION: MULTIPLE FACTORS, INCLUDING BOTH GENETIC AND ENVIRONMENTAL MECHANISMS, APPEAR TO PLAY A ROLE IN THE AETIOLOGY OF HEADACHE. AN INTERESTING AREA OF STUDY IS THE POSSIBLE INVOLVEMENT OF EPIGENETIC MECHANISMS IN HEADACHE DEVELOPMENT AND THE TRANSFORMATION TO CHRONIC HEADACHE, AND THE POTENTIAL ROLE OF THESE FACTORS AS A THERAPEUTIC TARGET. METHODS: WE PERFORMED A LITERATURE REVIEW OF THE INVOLVEMENT OF DIFFERENT EPIGENETIC MECHANISMS IN HEADACHE, MAINLY USING THE MEDLINE/PUBMED DATABASE. TO THIS END, WE USED THE FOLLOWING ENGLISH SEARCH TERMS: HEADACHE, MIGRAINE, EPIGENETICS, DNA METHYLATION, HISTONES, NON-CODING RNA, AND MIRNA. RESULTS: A TOTAL OF 15 ENGLISH-LANGUAGE PUBLICATIONS RELATED TO THE ABOVE TERMS WERE OBTAINED. CONCLUSION: THERE IS LIMITED BUT CONSISTENT EVIDENCE OF THE RELATIONSHIP BETWEEN EPIGENETICS AND HEADACHE; IT IS THEREFORE ESSENTIAL TO CONTINUE RESEARCH OF EPIGENETIC CHANGES IN HEADACHE. THIS MAY HELP TO UNDERSTAND THE PATHOPHYSIOLOGY OF HEADACHE AND EVEN TO IDENTIFY CANDIDATE BIOMARKERS AND NEW, MORE EFFECTIVE, THERAPEUTIC TARGETS. 2021 5 728 39 CAN WE IDENTIFY PATIENTS WITH HIGH RISK OF OSTEOARTHRITIS PROGRESSION WHO WILL RESPOND TO TREATMENT? A FOCUS ON BIOMARKERS AND FRAILTY. OSTEOARTHRITIS (OA), A DISEASE AFFECTING DIFFERENT PATIENT PHENOTYPES, APPEARS AS AN OPTIMAL CANDIDATE FOR PERSONALIZED HEALTHCARE. THE AIM OF THE DISCUSSIONS OF THE EUROPEAN SOCIETY FOR CLINICAL AND ECONOMIC ASPECTS OF OSTEOPOROSIS AND OSTEOARTHRITIS (ESCEO) WORKING GROUP WAS TO EXPLORE THE VALUE OF MARKERS OF DIFFERENT SOURCES IN DEFINING DIFFERENT PHENOTYPES OF PATIENTS WITH OA. THE ESCEO ORGANIZED A SERIES OF MEETINGS TO EXPLORE THE POSSIBILITY OF IDENTIFYING PATIENTS WHO WOULD MOST BENEFIT FROM TREATMENT FOR OA, ON THE BASIS OF RECENT DATA AND EXPERT OPINION. IN THE FIRST MEETING, PATIENT PHENOTYPES WERE IDENTIFIED ACCORDING TO THE NUMBER OF AFFECTED JOINTS, BIOMECHANICAL FACTORS, AND THE PRESENCE OF LESIONS IN THE SUBCHONDRAL BONE. IN THE SECOND MEETING, SUMMARIZED IN THE PRESENT ARTICLE, THE WORKING GROUP EXPLORED OTHER MARKERS INVOLVED IN OA. PROFILES OF PATIENTS MAY BE DEFINED ACCORDING TO THEIR LEVEL OF PAIN, FUNCTIONAL LIMITATION, AND PRESENCE OF COEXISTENT CHRONIC CONDITIONS INCLUDING FRAILTY STATUS. A CONSIDERABLE AMOUNT OF DATA SUGGESTS THAT MAGNETIC RESONANCE IMAGING MAY ALSO ASSIST IN DELINEATING DIFFERENT PHENOTYPES OF PATIENTS WITH OA. AMONG MULTIPLE BIOCHEMICAL BIOMARKERS IDENTIFIED, NONE IS SUFFICIENTLY VALIDATED AND RECOGNIZED TO IDENTIFY PATIENTS WHO SHOULD BE TREATED. CONSIDERABLE EFFORTS ARE ALSO BEING MADE TO IDENTIFY GENETIC AND EPIGENETIC FACTORS INVOLVED IN OA, BUT RESULTS ARE STILL LIMITED. THE MANY POTENTIAL BIOMARKERS THAT COULD BE USED AS POTENTIAL STRATIFIERS ARE PROMISING, BUT MORE RESEARCH IS NEEDED TO CHARACTERIZE AND QUALIFY THE EXISTING BIOMARKERS AND TO IDENTIFY NEW CANDIDATES. 2015 6 6458 42 TIME COURSE OF DNA METHYLATION IN PAIN CONDITIONS: FROM EXPERIMENTAL MODELS TO HUMANS. BACKGROUND AND OBJECTIVE: THROUGHOUT THE LAST DECADE, RESEARCH HAS UNCOVERED ASSOCIATIONS BETWEEN PAIN AND EPIGENETIC ALTERATIONS CAUSED BY ENVIRONMENTAL FACTORS. SPECIFICALLY, STUDIES HAVE DEMONSTRATED CORRELATIONS BETWEEN PAIN CONDITIONS AND ALTERED DNA METHYLATION PATTERNS. THUS, DNA METHYLATION HAS BEEN REVEALED AS A POSSIBLE MODULATOR OR CONTRIBUTOR TO PAIN CONDITIONS, PROVIDING A POTENTIAL THERAPEUTIC TARGET FOR TREATMENT BY DNA METHYLATION MODIFICATION. TO DEVELOP SUCH TREATMENTS, IT IS NECESSARY TO CLARIFY A WIDE NUMBER OF ASPECTS ON HOW DNA METHYLATION AFFECTS PAIN PERCEPTION; FIRST AND FOREMOST, THE TEMPORAL DYNAMICS. THE OBJECTIVE OF THE PRESENT REVIEW IS TO PROVIDE AN OVERVIEW OF CURRENT KNOWLEDGE ON TEMPORAL DYNAMICS OF DNA METHYLATION IN RESPONSE TO PAIN, AND TO INVESTIGATE IF A TIMEFRAME CAN BE ESTABLISHED BASED ON THE DATA OF CURRENTLY PUBLISHED STUDIES. DATABASES AND DATA TREATMENT: PUBMED, MEDLINE, GOOGLE SCHOLAR AND EMBASE WERE SEARCHED COMPREHENSIVELY FOR STUDIES OF DNA METHYLATION IN NEUROPATHIC, INFLAMMATORY AND ALTERNATIVE ANIMAL PAIN MODELS, AND IN CHRONIC PAIN PATIENTS INCLUDING COMPLEX REGIONAL PAIN SYNDROME, CHRONIC POSTSURGICAL PAIN, CHRONIC WIDESPREAD PAIN, FIBROMYALGIA AND CROHN'S DISEASE. RESULTS: WE IDENTIFIED 34 ARTICLES HIGHLIGHTING VARIATIONS IN TEMPORAL DYNAMICS OF DNA METHYLATION ACROSS SPECIES AND BETWEEN DIFFERENT TYPES OF PAIN. THESE STUDIES REPRESENT A STARTING POINT TO UNCOVER NEW INSIGHTS IN THE DNA METHYLATION TIME COURSE IN PAIN. CONCLUSIONS: NO TIMEFRAME CAN CURRENTLY BE MADE FOR THE DNA METHYLATION RESPONSE TO PAIN IN ANY OF THE REVIEWED CONDITIONS, HIGHLIGHTING AN IMPORTANT FOCUS AREA FOR FUTURE RESEARCH. 2021 7 6159 40 THE GENETICS AND EPIGENETICS OF FATIGUE. FATIGUE IS A COMMON SYMPTOM AND INCLUDES BOTH PHYSICAL AND MENTAL COMPONENTS. IT CAN BE ASSOCIATED WITH A VARIETY OF DIFFERENT SYNDROMES AND DISEASES, BUT IN MANY CASES IS NOT ASSOCIATED WITH OTHER COMORBID CONDITIONS. MOST HUMANS HAVE EXPERIENCED ACUTE FATIGUE IN RELATION TO DIFFERENT STRESSORS. ACUTE FATIGUE TYPICALLY DECREASES AS THE EFFECT OF THE TRIGGERING FACTOR IS REDUCED AND A NORMAL HOMEOSTATIC BALANCE IS RESTORED. FATIGUE THAT PERSISTS FOR 6 MONTHS OR MORE IS TERMED CHRONIC FATIGUE. CHRONIC FATIGUE (CF) IN COMBINATION WITH A MINIMUM OF 4 OF 8 SYMPTOMS AND THE ABSENCE OF DISEASES THAT COULD EXPLAIN THESE SYMPTOMS, CONSTITUTE THE CASE DEFINITION FOR CHRONIC FATIGUE SYNDROME. IN SPITE OF ITS PREVALENCE, THE BIOLOGY OF FATIGUE IS RELATIVELY POORLY UNDERSTOOD AND BIOLOGICAL MARKERS HAVE NOT YET BEEN IDENTIFIED. THIS LITERATURE SEARCH WAS PERFORMED IN PUBMED TO IDENTIFY RESEARCH ON THE GENETICS AND EPIGENETICS OF FATIGUE. PUBLICATIONS WERE INCLUDED IF FATIGUE WAS A MAJOR TOPIC AND THE TOPIC WAS COMBINED WITH GENETIC AND/OR EPIGENETIC MEASUREMENTS IN ADULT HUMANS. A TOTAL OF 40 PUBLICATIONS WERE IDENTIFIED. ALTHOUGH ALTERED FUNCTIONING IN THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS, THE SEROTONERGIC SYSTEM, AND ASSOCIATIONS WITH INFECTIOUS AGENTS HAVE BEEN IDENTIFIED, THE SEARCH FOR GENETIC OR EPIGENETIC MARKERS OF FATIGUE, EITHER IN THE CONTEXT OF CF OR CHRONIC FATIGUE SYNDROME (CFS) HAS BEEN RELATIVELY UNPRODUCTIVE OR, IN THE CASE OF EPIGENETICS, NONEXISTENT. ALTHOUGH SEVERAL STUDIES, BOTH HYPOTHESIS-TESTING AND HYPOTHESIS-GENERATING, HAVE BEEN PERFORMED TO SEARCH FOR BIOMARKERS, THEY HAVE MOSTLY BEEN UNDERPOWERED, RESTRICTED BY THE HETEROGENEITY OF THE PHENOTYPE, OR LIMITED BY AN UNSYSTEMATIC STUDY DESIGN. TO BE ABLE TO CONFIRM THE HYPOTHESIS THAT RISK FOR, OR LEVELS OF, FATIGUE ARE INFLUENCED BY THE GENETIC OR EPIGENETIC BACKGROUND OF AN INDIVIDUAL, STUDIES NEED TO BE BASED ON LARGER SAMPLE SIZES WITH A MORE CLEARLY DEFINED PHENOTYPE. STUDIES NEED TO FOCUS NOT ONLY ON THE INFLUENCE OF A SINGLE ASPECT SUCH AS SINGLE NUCLEOTIDE POLYMORPHISMS (SNPS) OR DIFFERENTIAL GENE EXPRESSION ON DISEASE RISK OR STATE, BUT ALSO ON THE SYSTEMS BIOLOGY BEHIND THE DISEASE IN COMBINATION WITH INFORMATION ON ENVIRONMENTAL INFLUENCES AND VALIDATION OF FINDINGS IN FUNCTIONAL STUDIES. 2010 8 6916 28 [WHAT IS MIGRAINE?]. MIGRAINE IS A MULTIFACTORIAL AND HETEROGENEOUS DISORDER. DIAGNOSTIC CRITERIA HAVE BEEN ESTABLISHED BY THE INTERNATIONAL HEADACHE SOCIETY, HOWEVER THESE ARE ONLY SUPPORTIVE IN TERMS OF DEFINITION. THE PATHOPHYSIOLOGY INVOLVES NEURONAL AND VASCULAR PHENOMENA. THE FORMER IS SUPPORTED BY THE CORTICAL SPREADING DEPRESSION BEING THE AURA CORRELATE AND BY BRAINSTEM AND HYPOTHALAMIC ACTIVATION DURING THE PAIN PHASE; THE LATTER IS SUGGESTED BY THE ASSOCIATION BETWEEN MIGRAINE AND CARDIOVASCULAR DISEASE AND FINDINGS OF PATHOLOGICAL VASOREACTIVITY AND ENDOTHELIAL DYSFUNCTION. TRIPTANS AND CALCITONIN GENE-RELATED PEPTIDE RECEPTOR ANTAGONISTS SHOW ONLY A RELATIVE MIGRAINE-SPECIFIC ACTION; UP TO 30% OF PATIENTS ARE NONRESPONDERS. DESPITE A CLEAR GENETIC COMPONENT, THE DISCOVERY OF SPECIFIC GENES FOR COMMON FORMS OF MIGRAINE REMAINS ELUSIVE. ELECTROPHYSIOLOGICAL STUDIES CONSISTENTLY INDICATE A CHARACTERISTIC "DYSHABITUATION" CONCURRING WITH CLINICAL FEATURES OF ALTERED SENSORY PERCEPTION. THE AGE- AND SEX-SPECIFIC PATTERN ALONG WITH THE EFFECT OF EXTERNAL FACTORS ON THE COURSE OF MIGRAINE ARGUE IN FAVOR OF THE INVOLVEMENT OF EPIGENETIC MECHANISMS. KNOWLEDGE ABOUT MIGRAINE IS STILL LIMITED, WHICH HAMPERS A DEFINITION. 2009 9 6846 26 [MIGRAINE: IGNITION OF THE BRAIN]. ALTHOUGH OUR KNOWLEDGE OF WHICH SYSTEMS ARE ACTIVATED DURING MIGRAINE IS REASONABLY COMPLETE, WHY THE SYSTEM IS ACTIVATED REMAINS UNKNOWN. INCORPORATING THE FINDINGS OBTAINED IN STUDIES ON PAIN IN GENERAL HAS ALLOWED A MORE INTEGRATED MODEL TO BE GENERATED. ACCORDING TO THIS NEW MODEL, THERE IS AN ANATOMICAL SUBSTRATE CONSISTING IN A COMPLEX FRAMEWORK OF PAIN THAT IS MADE UP NOT ONLY OF THE TRIGEMINOVASCULAR SYSTEM (END PATHWAY) BUT OF A NUMBER OF NETWORKS THAT ARE IN TURN CONNECTED TO ONE ANOTHER, LIKE THE NEUROLIMBIC, THE ASCENDING AND DESCENDING MODULATORY SYSTEM. THIS COMPLEX NETWORK IS RESPONSIBLE FOR MODULATING AND CONVEYING NOCICEPTIVE SIGNALS. IN PATIENTS WITH MIGRAINE, HYPEREXCITABILITY OF THIS FRAMEWORK IS CONDITIONED BY GENETIC AND EPIGENETIC ALTERATIONS. EPIGENETIC CHANGES ARE CHEMICAL MODIFICATIONS AFFECTING CHROMATIN, WHICH MODULATES THE ACTIVITY OF GENES WITHOUT MODIFYING THE DNA SEQUENCE, AND WHICH ARE CAPABLE OF MODULATING THE EXPRESSION OF GENES INVOLVED IN A NUMBER OF DIFFERENT ASPECTS, SUCH AS PLASTICITY, SYSTEM EXCITABILITY, MEMORY OF PAIN OR MOODS. IN TURN, THE PRESENCE OF EXTERNAL FACTORS (SUCH AS ENVIRONMENTAL CHANGES OR ALCOHOL) AND INTERNAL FACTORS (SUCH AS HORMONES OR SLEEP DISORDERS) CONTRIBUTE TO ACTIVATE THIS LOADED ANATOMICAL SUBSTRATE, RESULTING IN THE ATTACK OF MIGRAINE. 2013 10 3108 26 GENOMICS OF PAIN IN OSTEOARTHRITIS. OSTEOARTHRITIS (OA) ACCOUNTS FOR THE MAJORITY OF THE DISEASE BURDEN FOR MUSCULOSKELETAL DISORDERS AND IS ONE OF THE LEADING CAUSES OF DISABILITY WORLDWIDE. THIS DISABILITY IS THE RESULT NOT OF THE CARTILAGE LOSS THAT DEFINES OA RADIOGRAPHICALLY, BUT OF THE CHRONIC PAIN WHOSE PRESENCE DEFINES SYMPTOMATIC OA. IT IS BECOMING CLEAR THAT MANY GENES, EACH WITH A SMALL EFFECT SIZE, CONTRIBUTE TO THE RISK OF DEVELOPING OA. HOWEVER, THE GENETICS OF OA PAIN ARE ONLY JUST STARTING TO BE EXPLORED. THIS REVIEW WILL DESCRIBE THE FIRST GENES TO HAVE BEEN IDENTIFIED IN GENOMIC STUDIES OF OA PAIN, AS WELL AS THE POSSIBLE DUAL ROLES OF GENES PREVIOUSLY IDENTIFIED IN GENOMIC STUDIES OF OA IN THE CONTEXT OF PAIN. DIFFICULTIES ASSOCIATED WITH ATTEMPTING TO CHARACTERISE THE GENETICS OF OA PAIN WILL BE DISCUSSED AND PROMISING FUTURE AVENUES OF RESEARCH INTO GENETIC AND EPIGENETIC FACTORS AFFECTING OA PAIN DESCRIBED. 2013 11 2815 36 FIBROMYALGIA: GENETICS AND EPIGENETICS INSIGHTS MAY PROVIDE THE BASIS FOR THE DEVELOPMENT OF DIAGNOSTIC BIOMARKERS. FIBROMYALGIA IS A DISEASE CHARACTERIZED BY CHRONIC WIDESPREAD PAIN WITH ADDITIONAL SYMPTOMS, SUCH AS JOINT STIFFNESS, FATIGUE, SLEEP DISTURBANCE, COGNITIVE DYSFUNCTION, AND DEPRESSION. CURRENTLY, FIBROMYALGIA DIAGNOSIS IS BASED EXCLUSIVELY ON A COMPREHENSIVE CLINICAL ASSESSMENT, ACCORDING TO 2016 ACR CRITERIA, BUT VALIDATED BIOLOGICAL BIOMARKERS ASSOCIATED WITH FIBROMYALGIA HAVE NOT YET BEEN IDENTIFIED. GENOME-WIDE ASSOCIATION STUDIES INVESTIGATED GENES POTENTIALLY INVOLVED IN FIBROMYALGIA PATHOGENESIS HIGHLIGHTING THAT GENETIC FACTORS ARE POSSIBLY RESPONSIBLE FOR UP TO 50% OF THE DISEASE SUSCEPTIBILITY. POTENTIAL CANDIDATE GENES FOUND ASSOCIATED TO FIBROMYALGIA ARE SLC64A4, TRPV2, MYT1L, AND NRXN3. FURTHERMORE, A GENE-ENVIRONMENTAL INTERACTION HAS BEEN PROPOSED AS TRIGGERING MECHANISM, THROUGH EPIGENETIC ALTERATIONS: IN PARTICULAR, FIBROMYALGIA APPEARS TO BE CHARACTERIZED BY A HYPOMETHYLATED DNA PATTERN, IN GENES IMPLICATED IN STRESS RESPONSE, DNA REPAIR, AUTONOMIC SYSTEM RESPONSE, AND SUBCORTICAL NEURONAL ABNORMALITIES. DIFFERENCES IN THE GENOME-WIDE EXPRESSION PROFILE OF MICRORNAS WERE FOUND AMONG MULTIPLE TISSUES, INDICATING THE INVOLVEMENT OF DISTINCT PROCESSES IN FIBROMYALGIA PATHOGENESIS. FURTHER STUDIES SHOULD BE DEDICATED TO STRENGTH THESE PRELIMINARY FINDINGS, IN LARGER MULTICENTER COHORTS, TO IDENTIFY RELIABLE DIRECTIONS FOR BIOMARKER RESEARCH AND CLINICAL PRACTICE. 2019 12 2108 40 EPIGENETIC FACTORS RELATED TO LOW BACK PAIN: A SYSTEMATIC REVIEW OF THE CURRENT LITERATURE. LOW BACK PAIN (LBP) IS ONE OF THE MOST COMMON CAUSES OF PAIN AND DISABILITY. AT PRESENT, TREATMENT AND INTERVENTIONS FOR ACUTE AND CHRONIC LOW BACK PAIN OFTEN FAIL TO PROVIDE SUFFICIENT LEVELS OF PAIN RELIEF, AND FULL FUNCTIONAL RESTORATION CAN BE CHALLENGING. CONSIDERING THE SIGNIFICANT SOCIO-ECONOMIC BURDEN AND RISK-TO-BENEFIT RATIO OF MEDICAL AND SURGICAL INTERVENTION IN LOW BACK PAIN PATIENTS, THE IDENTIFICATION OF RELIABLE BIOMARKERS SUCH AS EPIGENETIC FACTORS ASSOCIATED WITH LOW BACK PAIN COULD BE USEFUL IN CLINICAL PRACTICE. THE AIM OF THIS STUDY WAS TO REVIEW THE AVAILABLE LITERATURE REGARDING THE EPIGENETIC FACTORS ASSOCIATED WITH LOW BACK PAIN. THIS REVIEW WAS CARRIED OUT IN ACCORDANCE WITH PREFERENTIAL REPORTING ITEMS FOR SYSTEMATIC REVIEWS AND META-ANALYSES (PRISMA) GUIDELINES. THE SEARCH WAS CARRIED OUT IN OCTOBER 2022. ONLY PEER-REVIEWED ARTICLES WERE CONSIDERED FOR INCLUSION. FOURTEEN STUDIES WERE INCLUDED AND SHOWED PROMISING RESULTS IN TERMS OF RELIABLE MARKERS. EPIGENETIC MARKERS FOR LBP HAVE THE POTENTIAL TO SIGNIFICANTLY MODIFY DISEASE MANAGEMENT. MOST RECENT EVIDENCE SUGGESTS THAT EPIGENETICS IS A MORE PROMISING FIELD FOR THE IDENTIFICATION OF FACTORS ASSOCIATED WITH LBP, OFFERING A RATIONALE FOR FURTHER INVESTIGATION IN THIS FIELD WITH THE LONG-TERM GOAL OF FINDING EPIGENETIC BIOMARKERS THAT COULD CONSTITUTE BIOLOGICAL TARGETS FOR DISEASE MANAGEMENT AND TREATMENT. 2023 13 2611 32 EPIGENETICS: A PROMISING PARADIGM FOR BETTER UNDERSTANDING AND MANAGING PAIN. EPIGENETIC REGULATION OF GENE EXPRESSION IS A RAPIDLY GROWING AREA OF RESEARCH. CONSIDERING THE LONGEVITY AND PLASTICITY OF NEURONS, THE STUDIES ON EPIGENETIC PATHWAYS IN THE NERVOUS SYSTEM SHOULD BE OF SPECIAL INTEREST FOR BOTH EPIGENETICISTS AND NEUROSCIENTISTS. ACTIVATION OR INACTIVATION OF DIFFERENT EPIGENETIC PATHWAYS BECOMES MORE PRONOUNCED WHEN THE CELLS EXPERIENCE RAPID CHANGES IN THEIR ENVIRONMENT, AND SUCH CHANGES CAN BE EASILY CAUSED BY INJURY AND INFLAMMATION, RESULTING IN PAIN PERCEPTION OR DISTORTION OF PAIN PERCEPTION (EG, HYPERALGESIA). THEREFORE, IN THIS REGARD, THE FIELD OF PAIN IS AT AN ADVANTAGE TO STUDY THE EPIGENETIC PATHWAYS. MORE IMPORTANTLY, UNDERSTANDING PAIN FROM AN EPIGENETICS POINT OF VIEW WOULD PROVIDE A NEW PARADIGM FOR DEVELOPING DRUGS OR STRATEGIES FOR PAIN MANAGEMENT. IN THIS REVIEW, WE INTRODUCE BASIC CONCEPTS OF EPIGENETICS, INCLUDING CHROMATIN DYNAMICS, HISTONE MODIFICATIONS, DNA METHYLATION, AND RNA-INDUCED GENE SILENCING. IN ADDITION, WE PROVIDE EVIDENCE FROM PUBLISHED STUDIES SUGGESTING WIDE IMPLICATION OF DIFFERENT EPIGENETIC PATHWAYS WITHIN PAIN PATHWAYS. PERSPECTIVE: THIS ARTICLE PROVIDES A BRIEF OVERVIEW OF EPIGENETIC PATHWAYS FOR GENE REGULATION AND HIGHLIGHTS THEIR INVOLVEMENT IN PAIN. OUR GOAL IS TO EXPOSE THE READERS TO THESE CONCEPTS SO THAT PAIN-RELATED PHENOTYPES CAN BE INVESTIGATED FROM THE EPIGENETIC POINT OF VIEW. 2013 14 2523 39 EPIGENETICS AND THE TRANSITION FROM ACUTE TO CHRONIC PAIN. OBJECTIVE: THE OBJECTIVE OF THIS STUDY WAS TO REVIEW THE EPIGENETIC MODIFICATIONS INVOLVED IN THE TRANSITION FROM ACUTE TO CHRONIC PAIN AND TO IDENTIFY POTENTIAL TARGETS FOR THE DEVELOPMENT OF NOVEL, INDIVIDUALIZED PAIN THERAPEUTICS. BACKGROUND: EPIGENETICS IS THE STUDY OF HERITABLE MODIFICATIONS IN GENE EXPRESSION AND PHENOTYPE THAT DO NOT REQUIRE A CHANGE IN GENETIC SEQUENCE TO MANIFEST THEIR EFFECTS. ENVIRONMENTAL TOXINS, MEDICATIONS, DIET, AND PSYCHOLOGICAL STRESSES CAN ALTER EPIGENETIC PROCESSES SUCH AS DNA METHYLATION, HISTONE ACETYLATION, AND RNA INTERFERENCE. AS EPIGENETIC MODIFICATIONS POTENTIALLY PLAY AN IMPORTANT ROLE IN INFLAMMATORY CYTOKINE METABOLISM, STEROID RESPONSIVENESS, AND OPIOID SENSITIVITY, THEY ARE LIKELY KEY FACTORS IN THE DEVELOPMENT OF CHRONIC PAIN. ALTHOUGH OUR KNOWLEDGE OF THE HUMAN GENETIC CODE AND DISEASE-ASSOCIATED POLYMORPHISMS HAS GROWN SIGNIFICANTLY IN THE PAST DECADE, WE HAVE NOT YET BEEN ABLE TO ELUCIDATE THE MECHANISMS THAT LEAD TO THE DEVELOPMENT OF PERSISTENT PAIN AFTER NERVE INJURY OR SURGERY. DESIGN: THIS IS A FOCUSED LITERATURE REVIEW OF EPIGENETIC SCIENCE AND ITS RELATIONSHIP TO CHRONIC PAIN. RESULTS: SIGNIFICANT LABORATORY AND CLINICAL DATA SUPPORT THE NOTION THAT EPIGENETIC MODIFICATIONS ARE AFFECTED BY THE ENVIRONMENT AND LEAD TO DIFFERENTIAL GENE EXPRESSION. SIMILAR TO MECHANISMS INVOLVED IN THE DEVELOPMENT OF CANCER, NEURODEGENERATIVE DISEASE, AND INFLAMMATORY DISORDERS, THE LITERATURE ENDORSES AN IMPORTANT POTENTIAL ROLE FOR EPIGENETICS IN CHRONIC PAIN. CONCLUSIONS: EPIGENETIC ANALYSIS MAY IDENTIFY MECHANISMS CRITICAL TO THE DEVELOPMENT OF CHRONIC PAIN AFTER INJURY, AND MAY PROVIDE NEW PATHWAYS AND TARGET MECHANISMS FOR FUTURE DRUG DEVELOPMENT AND INDIVIDUALIZED MEDICINE. 2012 15 1686 29 DRUGGING THE PAIN EPIGENOME. MORE THAN 20% OF ADULTS WORLDWIDE EXPERIENCE DIFFERENT TYPES OF CHRONIC PAIN, WHICH ARE FREQUENTLY ASSOCIATED WITH SEVERAL COMORBIDITIES AND A DECREASE IN QUALITY OF LIFE. SEVERAL APPROVED PAINKILLERS ARE AVAILABLE, BUT CURRENT ANALGESICS ARE OFTEN HAMPERED BY INSUFFICIENT EFFICACY AND/OR SEVERE ADVERSE EFFECTS. CONSEQUENTLY, NOVEL STRATEGIES FOR SAFE, HIGHLY EFFICACIOUS TREATMENTS ARE HIGHLY DESIRABLE, PARTICULARLY FOR CHRONIC PAIN. EPIGENETIC MECHANISMS SUCH AS DNA METHYLATION, HISTONE MODIFICATIONS AND MICRORNAS (MIRNAS) STRONGLY AFFECT THE REGULATION OF GENE EXPRESSION, POTENTIALLY FOR LONG PERIODS OVER YEARS OR EVEN GENERATIONS, AND HAVE BEEN ASSOCIATED WITH PATHOPHYSIOLOGICAL PAIN. SEVERAL STUDIES, MOSTLY IN ANIMALS, REVEALED THAT INHIBITORS OF DNA METHYLATION, ACTIVATORS AND INHIBITORS OF HISTONE MODIFICATION AND MODULATORS OF MIRNAS REVERSE A NUMBER OF PATHOLOGICAL CHANGES IN THE PAIN EPIGENOME, WHICH ARE ASSOCIATED WITH ALTERED EXPRESSION OF PAIN-RELEVANT GENES. THIS EPIGENETIC MODULATION MIGHT THEN REDUCE THE NOCICEPTIVE RESPONSE AND PROVIDE NOVEL THERAPEUTIC OPTIONS FOR ANALGESIC THERAPY OF CHRONIC PAIN STATES. HOWEVER, A NUMBER OF CHALLENGES, SUCH AS NONSPECIFIC EFFECTS AND POOR DELIVERY TO TARGET CELLS AND TISSUES, HINDER THE RAPID DEVELOPMENT OF SUCH ANALGESICS. IN THIS REVIEW, WE CRITICALLY SUMMARIZE DATA ON EPIGENETICS AND PAIN, FOCUSING ON CHALLENGES IN CLINICAL DEVELOPMENT AS WELL AS POSSIBLE NEW APPROACHES TO THE DRUG MODULATION OF THE PAIN EPIGENOME. 2017 16 1248 32 CURRENT EVIDENCE FOR BIOLOGICAL BIOMARKERS AND MECHANISMS UNDERLYING ACUTE TO CHRONIC PAIN TRANSITION ACROSS THE PEDIATRIC AGE SPECTRUM. CHRONIC PAIN IS HIGHLY PREVALENT IN THE PEDIATRIC POPULATION. MANY FACTORS ARE INVOLVED IN THE TRANSITION FROM ACUTE TO CHRONIC PAIN. CURRENTLY, THERE ARE CONCEPTUAL MODELS PROPOSED, BUT THEY LACK A MECHANISTICALLY SOUND INTEGRATED THEORY CONSIDERING THE STAGES OF CHILD DEVELOPMENT. OBJECTIVE BIOMARKERS ARE CRITICALLY NEEDED FOR THE DIAGNOSIS, RISK STRATIFICATION, AND PROGNOSIS OF THE PATHOLOGICAL STAGES OF PAIN CHRONIFICATION. IN THIS ARTICLE, WE SUMMARIZE THE CURRENT EVIDENCE ON MECHANISMS AND BIOMARKERS OF ACUTE TO CHRONIC PAIN TRANSITIONS IN INFANTS AND CHILDREN THROUGH THE DEVELOPMENTAL LENS. THE GOAL IS TO IDENTIFY GAPS AND OUTLINE FUTURE DIRECTIONS FOR BASIC AND CLINICAL RESEARCH TOWARD A DEVELOPMENTALLY INFORMED THEORY OF PAIN CHRONIFICATION IN THE PEDIATRIC POPULATION. AT THE OUTSET, THE IMPORTANCE OF OBJECTIVE BIOMARKERS FOR CHRONIFICATION OF PAIN IN CHILDREN IS OUTLINED, FOLLOWED BY A SUMMARY OF THE CURRENT EVIDENCE ON THE MECHANISMS OF ACUTE TO CHRONIC PAIN TRANSITION IN ADULTS, IN ORDER TO CONTRAST WITH THE DEVELOPMENTAL MECHANISMS OF PAIN CHRONIFICATION IN THE PEDIATRIC POPULATION. EVIDENCE IS PRESENTED TO SHOW THAT CHRONIC PAIN MAY HAVE ITS ORIGIN FROM INSULTS EARLY IN LIFE, WHICH PRIME THE CHILD FOR THE DEVELOPMENT OF CHRONIC PAIN IN LATER LIFE. FURTHERMORE, AVAILABLE GENETIC, EPIGENETIC, PSYCHOPHYSICAL, ELECTROPHYSIOLOGICAL, NEUROIMAGING, NEUROIMMUNE, AND SEX MECHANISMS ARE DESCRIBED IN INFANTS AND OLDER CHILDREN. IN CONCLUSION, FUTURE DIRECTIONS ARE DISCUSSED WITH A FOCUS ON RESEARCH GAPS, TRANSLATIONAL AND CLINICAL IMPLICATIONS. UTILIZATION OF DEVELOPMENTAL MECHANISMS FRAMEWORK TO INFORM CLINICAL DECISION-MAKING AND STRATEGIES FOR PREVENTION AND MANAGEMENT OF ACUTE TO CHRONIC PAIN TRANSITIONS IN CHILDREN, IS HIGHLIGHTED. 2023 17 1736 31 EARLY DETECTION AND PREVENTION OF SCHIZOPHRENIC PSYCHOSIS-A REVIEW. PSYCHOTIC DISORDERS OFTEN RUN A CHRONIC COURSE AND ARE ASSOCIATED WITH A CONSIDERABLE EMOTIONAL AND SOCIAL IMPACT FOR PATIENTS AND THEIR RELATIVES. THEREFORE, EARLY RECOGNITION, COMBINED WITH THE POSSIBILITY OF PREVENTIVE INTERVENTION, IS URGENTLY WARRANTED SINCE THE DURATION OF UNTREATED PSYCHOSIS (DUP) SIGNIFICANTLY DETERMINES THE FURTHER COURSE OF THE DISEASE. IN ADDITION TO ESTABLISHED DIAGNOSTIC TOOLS, NEUROBIOLOGICAL FACTORS IN THE DEVELOPMENT OF SCHIZOPHRENIC PSYCHOSES ARE INCREASINGLY BEING INVESTIGATED. IT IS SHOWN THAT NUMEROUS MOLECULAR ALTERATIONS ALREADY EXIST BEFORE THE CLINICAL ONSET OF THE DISEASE. AS SCHIZOPHRENIC PSYCHOSES ARE NOT ELICITED BY A SINGLE MUTATION IN THE DEOXYRIBONUCLEIC ACID (DNA) SEQUENCE, EPIGENETICS LIKELY CONSTITUTE THE MISSING LINK BETWEEN ENVIRONMENTAL INFLUENCES AND DISEASE DEVELOPMENT AND COULD POTENTIALLY SERVE AS A BIOMARKER. THE RESULTS FROM TRANSCRIPTOMIC AND PROTEOMIC STUDIES POINT TO A DYSREGULATED IMMUNE SYSTEM, LIKELY EVOKED BY EPIGENETIC ALTERATIONS. DESPITE THE INCREASING KNOWLEDGE OF THE NEUROBIOLOGICAL MECHANISMS INVOLVED IN THE DEVELOPMENT OF PSYCHOTIC DISORDERS, FURTHER RESEARCH EFFORTS WITH LARGE POPULATION-BASED STUDY DESIGNS ARE NEEDED TO IDENTIFY SUITABLE BIOMARKERS. IN CONCLUSION, A COMBINATION OF BLOOD EXAMINATIONS, FUNCTIONAL IMAGING TECHNIQUES, ELECTROENCEPHALOGRAPHY (EEG) INVESTIGATIONS AND POLYGENIC RISK SCORES SHOULD BE CONSIDERED AS THE BASIS FOR PREDICTING HOW SUBJECTS WILL TRANSITION INTO MANIFEST PSYCHOSIS. 2021 18 2534 37 EPIGENETICS IN BIPOLAR DISORDER: A CRITICAL REVIEW OF THE LITERATURE. INTRODUCTION: BIPOLAR DISORDER (BD) IS A CHRONIC, DISABLING DISEASE CHARACTERISED BY ALTERNATE MOOD EPISODES, SWITCHING THROUGH DEPRESSIVE AND MANIC/HYPOMANIC PHASES. MOOD STABILIZERS, IN PARTICULAR LITHIUM SALTS, CONSTITUTE THE CORNERSTONE OF THE TREATMENT IN THE ACUTE PHASE AS WELL AS FOR THE PREVENTION OF RECURRENCES. THE PATHOPHYSIOLOGY OF BD AND THE MECHANISMS OF ACTION OF MOOD STABILIZERS REMAIN LARGELY UNKNOWN BUT SEVERAL PIECES OF EVIDENCE POINT TO GENE X ENVIRONMENT INTERACTIONS. EPIGENETICS, DEFINED AS THE REGULATION OF GENE EXPRESSION WITHOUT GENETIC CHANGES, COULD BE THE MOLECULAR SUBSTRATE OF THESE INTERACTIONS. IN THIS LITERATURE REVIEW, WE SUMMARIZE THE MAIN EPIGENETIC FINDINGS ASSOCIATED WITH BD AND RESPONSE TO MOOD STABILIZERS. METHODS: WE SEARCHED PUBMED, AND EMBASE DATABASES AND CLASSIFIED THE ARTICLES DEPENDING ON THE EPIGENETIC MECHANISMS (DNA METHYLATION, HISTONE MODIFICATIONS AND NON-CODING RNAS). RESULTS: WE PRESENT THE DIFFERENT EPIGENETIC MODIFICATIONS ASSOCIATED WITH BD OR WITH MOOD-STABILIZERS. THE MAJOR REPORTED MECHANISMS WERE DNA METHYLATION, HISTONE METHYLATION AND ACETYLATION, AND NON-CODING RNAS. OVERALL, THE ASSESSMENTS ARE POORLY HARMONIZED AND THE RESULTS ARE MORE LIMITED THAN IN OTHER PSYCHIATRIC DISORDERS (E.G. SCHIZOPHRENIA). HOWEVER, THE NATURE OF BD AND ITS TREATMENT OFFER EXCELLENT OPPORTUNITIES FOR EPIGENETIC RESEARCH: CLEAR IMPACT OF ENVIRONMENTAL FACTORS, CLINICAL VARIATION BETWEEN MANIC OR DEPRESSIVE EPISODES RESULTING IN POSSIBLE IDENTIFICATION OF STATE AND TRAITS BIOMARKERS, DOCUMENTED IMPACT OF MOOD-STABILIZERS ON THE EPIGENOME. CONCLUSION: EPIGENETIC IS A GROWING AND PROMISING FIELD IN BD THAT MAY SHED LIGHT ON ITS PATHOPHYSIOLOGY OR BE USEFUL AS BIOMARKERS OF RESPONSE TO MOOD-STABILIZER. 2021 19 4830 29 OLD AND NEW BIOMARKERS ASSOCIATED WITH ENDOTHELIAL DYSFUNCTION IN CHRONIC HYPERGLYCEMIA. CHRONIC HYPERGLYCEMIA AND VASCULAR DAMAGE ARE STRICTLY RELATED. BIOMARKERS OF VASCULAR DAMAGE HAVE BEEN INTENSIVELY STUDIED IN THE RECENT YEARS IN THE QUEST OF RELIABLE CARDIOVASCULAR RISK ASSESSMENT TOOLS ABLE TO FACILITATE RISK STRATIFICATION AND EARLY DETECTION OF VASCULAR IMPAIRMENT. THE PRESENT STUDY IS A NARRATIVE REVIEW WITH THE AIM OF REVISING THE AVAILABLE EVIDENCE ON CURRENT AND NOVEL MARKERS OF HYPERGLYCEMIA-INDUCED VASCULAR DAMAGE. AFTER A DISCUSSION OF CLASSIC TOOLS USED TO INVESTIGATE ENDOTHELIAL DYSFUNCTION, WE PROVIDE AN IN-DEPTH DESCRIPTION OF NOVEL CIRCULATING BIOMARKERS (CHEMOKINES, EXTRACELLULAR VESICLES, AND EPIGENETIC AND METABOLOMIC BIOMARKERS). APPROPRIATE USE OF A SINGLE AS WELL AS A CLUSTER OF THE DISCUSSED BIOMARKERS MIGHT ENABLE IN A NEAR FUTURE (A) THE PROMPT IDENTIFICATION OF TARGETED AND CUSTOMIZED TREATMENT STRATEGIES AND (B) THE FOLLOW-UP OF CARDIOVASCULAR TREATMENT EFFICACY OVER TIME IN CLINICAL RESEARCH AND/OR IN CLINICAL PRACTICE. 2021 20 641 43 BIOMARKERS OF MAJOR DEPRESSIVE DISORDER: KNOWING IS HALF THE BATTLE. MAJOR DEPRESSIVE DISORDER (MDD) IS A HETEROGENEOUS DISEASE WHICH IS WHY THERE ARE CURRENTLY NO SPECIFIC METHODS TO ACCURATELY TEST THE SEVERITY, ENDOPHENOTYPE OR THERAPY RESPONSE. THIS LACK OF PROGRESS IS PARTLY ATTRIBUTED TO THE COM-PLEXITY AND VARIABILITY OF DEPRESSION, IN ASSOCIATION WITH ANALYTICAL VARIABILITY OF CLINICAL LITERATURE AND THE WIDE NUMBER OF THEORETICALLY COMPLEX BIOMARKERS. THE LITERATURE ACCESSIBLE, INDICATES THAT MARKERS INVOLVED IN INFLAMMATORY, NEURO-TROPHIC AND METABOLIC PROCESSES AND COMPONENTS OF NEUROTRANSMITTERS AND NEUROENDOCRINE SYSTEMS ARE RATHER STRONG INDICATORS TO BE CONSIDERED CLINICALLY AND CAN BE MEASURED THROUGH GENETIC AND EPIGENETIC, TRANSCRIPTOMIC AND PROTEOMIC, METABOLOMICS AND NEUROIMAGING ASSESSMENTS. PROMISING BIOLOGIC SYSTEMS/MARKERS FOUND WERE I.E., GROWTH BIOMARKERS, ENDOCRINE MARKERS, OXIDANT STRESS MARKERS, PROTEOMIC AND CHRONIC INFLAMMATORY MARKERS, ARE DISCUSSED IN THIS REVIEW. SEVERAL LINES OF EVIDENCE SUGGEST THAT A PORTION OF MDD IS A DOPAMINE AGONIST-RESPONSIVE SUBTYPE. THIS REVIEW ANALYZES CONCISE REPORTS ON THE PATHOPHYSIOLOGICAL BIOMARKERS OF MDD AND THERAPEUTIC REACTIONS VIA PERIPHERAL DEVELOPMENTAL FACTORS, INFLAMMATIVE CYTOKINES, ENDOCRINE FACTORS AND METABOLIC MARKERS. VARIOUS LITERATURES ALSO SUPPORT THAT ENDOCRINE AND METABOLISM CHANGES ARE ASSOCIATED WITH MDD. ACCUMULATING EVIDENCE SUGGESTS THAT AT LEAST A PORTION OF MDD PATIENTS SHOW CHARACTERISTICS PATHOLOGICAL CHANGES REGARDING DIFFERENT CLINICAL PATHOLOGICAL BIOMARKERS. BY THIS REVIEW WE SUM UP ALL THE DIFFERENT BIOMARKERS PLAYING AN IMPORTANT ROLE IN THE DETECTION OR TREATMENT OF THE DIFFERENT PATIENTS SUFFERING FROM MDD. THE REVIEW ALSO GIVES AN OVERVIEW OF DIFFERENT BIOMARKER'S PLAYING A POTENTIAL ROLE IN MODULATING EFFECT OF MDD. 2021