1 5037 159 PHARMACOGENETICS IN PAIN TREATMENT. PAIN IS AN UNPLEASANT FEELING USUALLY RESULTING FROM TISSUE DAMAGE THAT CAN PERSIST ALONG WEEKS, MONTHS, OR EVEN YEARS AFTER THE INJURY, TURNING INTO PATHOLOGICAL CHRONIC PAIN, THE LEADING CAUSE OF DISABILITY. CURRENTLY, PHARMACOLOGY INTERVENTIONS ARE USUALLY THE FIRST-LINE THERAPY BUT THERE IS A HIGHLY VARIABLE ANALGESIC DRUG RESPONSE. PHARMACOGENETICS (PGX) OFFERS A MEANS TO IDENTIFY GENETIC BIOMARKERS THAT CAN PREDICT INDIVIDUAL ANALGESIC RESPONSE OPENING DOORS TO PRECISION MEDICINE. PGX ANALYZE THE WAY IN WHICH THE PRESENCE OF VARIATIONS IN THE DNA SEQUENCE (SINGLE-NUCLEOTIDE POLYMORPHISMS, SNPS) COULD BE RESPONSIBLE FOR PORTIONS OF THE POPULATION REACHING DIFFERENT LEVELS OF PAIN RELIEF (PHENOTYPE) DUE TO GENE INTERFERENCE IN THE DRUG MECHANISM OF ACTION (PHARMACODYNAMICS) AND/OR ITS CONCENTRATION AT THE PLACE OF ACTION (PHARMACOKINETICS). SNPS IN THE CYTOCHROME P450 ENZYMES GENES (CYP2D6) INFLUENCE METABOLISM OF CODEINE, TRAMADOL, HYDROCODONE, OXYCODONE, AND TRICYCLIC ANTIDEPRESSANTS. BLOOD CONCENTRATIONS OF SOME NSAIDS DEPEND ON CYP2C9 AND/OR CYP2C8 ACTIVITY. ADDITIONAL CANDIDATE GENES ENCODE FOR OPIOID RECEPTORS, TRANSPORTERS, AND OTHER MOLECULES IMPORTANT FOR PHARMACOTHERAPY IN PAIN MANAGEMENT. HOWEVER, PGX STUDIES ARE OFTEN CONTRADICTORY, SLOWING THE UPTAKE OF THIS INFORMATION. THIS IS LIKELY DUE, IN LARGE PART, TO A LACK OF ROBUST EVIDENCE DEMONSTRATING CLINICAL UTILITY AND TO ITS POLYGENIC RESPONSE MODULATED BY OTHER EXOGENOUS OR EPIGENETICS FACTORS. NOVEL THERAPIES, INCLUDING TARGETING OF EPIGENETIC CHANGES AND GENE THERAPY-BASED APPROACHES, BROADEN FUTURE OPTIONS TO IMPROVE UNDERSTANDING OF PAIN AND THE TREATMENT OF PEOPLE WHO SUFFER IT. 2018 2 6480 38 TOWARDS PRECISION MEDICINE IN GENERALIZED ANXIETY DISORDER: REVIEW OF GENETICS AND PHARMACO(EPI)GENETICS. GENERALIZED ANXIETY DISORDER (GAD) IS A PREVALENT AND CHRONIC MENTAL DISORDER THAT ELICITS WIDESPREAD FUNCTIONAL IMPAIRMENT. GIVEN THE HIGH DEGREE OF NON-RESPONSE/PARTIAL RESPONSE AMONG PATIENTS WITH GAD TO AVAILABLE PHARMACOLOGICAL TREATMENTS, THERE IS A STRONG NEED FOR NOVEL APPROACHES THAT CAN OPTIMIZE OUTCOMES, AND LEAD TO MEDICATIONS THAT ARE SAFER AND MORE EFFECTIVE. ALTHOUGH INVESTIGATIONS HAVE IDENTIFIED INTERESTING TARGETS PREDICTING TREATMENT RESPONSE THROUGH PHARMACOGENETICS (PGX), PHARMACO-EPIGENETICS, AND NEUROIMAGING METHODS, THESE STUDIES ARE OFTEN SOLITARY, NOT REPLICATED, AND CARRY SEVERAL LIMITATIONS. THIS REVIEW PROVIDES AN OVERVIEW OF THE CURRENT STATUS OF GAD GENETICS AND PGX AND PRESENTS POTENTIAL STRATEGIES TO IMPROVE TREATMENT RESPONSE BY COMBINING BETTER PHENOTYPING WITH PGX AND IMPROVED ANALYTICAL METHODS. THESE STRATEGIES CARRY THE DUAL BENEFIT OF DELIVERING DATA ON BIOMARKERS OF TREATMENT RESPONSE AS WELL AS POINTING TO DISEASE MECHANISMS THROUGH THE BIOLOGY OF THE MARKERS ASSOCIATED WITH RESPONSE. OVERALL, THESE EFFORTS CAN SERVE TO IDENTIFY CLINICAL, GENETIC, AND EPIGENETIC FACTORS THAT CAN BE INCORPORATED INTO A PHARMACO(EPI)GENETIC TEST THAT MAY ULTIMATELY IMPROVE TREATMENT RESPONSE AND REDUCE THE SOCIOECONOMIC BURDEN OF GAD. 2019 3 5038 36 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 6130 30 THE EPIGENETIC REGULATION OF THE OPIOID SYSTEM: NEW INDIVIDUALIZED PROMPT PREVENTION AND TREATMENT STRATEGIES. THE MOST WELL-KNOWN PHYSIOLOGICAL EFFECT ASSOCIATED WITH OPIOD SYSTEM IS THEIR EFFICACY IN PAIN REDUCTION OR ANALGESIA, ALTHOUGH THEIR EFFECT ON A VARIETY OF OTHER PHYSIOLOGICAL AND PHYSIOPHOLOGICAL FUNCTIONS HAS BECOME APPARENT IN RECENT YEARS. THIS REVIEW IS AN ATTEMPT TO CLARIFY IN MORE DETAIL THE EPIGENETIC REGULATION OF OPIOID SYSTEM TO UNDERSTAND WITH MORE PRECISION THEIR TRANSCRIPTIONAL AND POSTTRANSCRIPTIONAL REGULATION IN MULTIPLE PYISIOLOGICAL AND PHARMACOLOGICAL CONTEXTS. THE OPIOID RECEPTORS SHOW AN EPIGENETIC REGULATION AND OPIOID PEPTIDE PRECURSORS BY METHYLATION, CHROMATIN REMODELING AND MICRORNA. ALTHOUGH THE OPIOID RECEPTOR PROMOTERS HAVE SIMILARITY BETWEEN THEM, THEY USE DIFFERENT EPIGENETIC REGULATION FORMS AND THEY EXHIBIT DIFFERENT PATTERN OF EXPRESSION DURING THE CELL DIFFERENTIATION. DNA METHYLATION IS ALSO CONFIRMED IN OPIOID PEPTIDE PRECURSORS, BEING IMPORTANT FOR GENE EXPRESSION AND TISSUE SPECIFICITY. UNDERSTANDING THE EPIGENETIC BASIS OF THOSE PHYSIOLOGICAL AND PHYSIOPATHOLOGICAL PROCESESS IS ESSENTIAL FOR THE DEVELOPMENT OF INDIVIDUALIZED PROMPT PREVENTION AND TREATMENT STRATEGIES. 2015 5 5042 53 PHARMACOGENOMICS IN PAIN TREATMENT. THE EXPERIENCE OF CHRONIC PAIN IS ONE OF THE COMMONEST REASONS FOR SEEKING MEDICAL ATTENTION, BEING A MAJOR ISSUE IN CLINICAL PRACTICE. WHILE PAIN IS A UNIVERSAL EXPERIENCE, ONLY A SMALL PROPORTION OF PEOPLE WHO FELT PAIN DEVELOP PAIN SYNDROMES. IN ADDITION, PAINKILLERS ARE ASSOCIATED WITH WIDE INTER-INDIVIDUAL VARIABILITY IN THE ANALGESIC RESPONSE. THIS MAY BE PARTLY EXPLAINED BY THE PRESENCE OF SINGLE NUCLEOTIDE POLYMORPHISMS IN GENES ENCODING MOLECULAR ENTITIES INVOLVED IN PHARMACODYNAMICS AND PHARMACOKINETICS. HOWEVER, UPTAKE OF THIS INFORMATION HAS BEEN SLOW DUE IN LARGE PART TO THE LACK OF ROBUST EVIDENCES DEMONSTRATING CLINICAL UTILITY. FURTHERMORE, NOVEL THERAPIES, INCLUDING TARGETING OF EPIGENETIC CHANGES AND GENE THERAPY-BASED APPROACHES ARE FURTHER BROADENING FUTURE OPTIONS FOR THE TREATMENT OF CHRONIC PAIN. THE AIM OF THIS ARTICLE IS TO REVIEW THE EVIDENCES BEHIND PHARMACOGENETICS (PGX) TO INDIVIDUALIZE THERAPY (BOOSTING THE EFFICACY AND MINIMIZING POTENTIAL TOXICITY) AND GENES IMPLICATED IN PAIN MEDICINE, IN TWO PARTS: (I) GENETIC VARIABILITY WITH PAIN SENSITIVITY AND ANALGESIC RESPONSE; AND (II) PHARMACOLOGICAL CONCEPTS APPLIED ON PGX. 2016 6 4631 33 NEUROGENETICS OF ACUTE AND CHRONIC OPIATE/OPIOID ABSTINENCE: TREATING SYMPTOMS AND THE CAUSE. THIS REVIEW BEGINS WITH A COMPREHENSIVE HISTORY OF OPIOID DEPENDENCE AND TREATMENT IN THE UNITED STATES. THE FOCUS IS AN EVIDENCE-BASED TREATMENT MODEL FOR OPIOID/OPIATE DEPENDENT INDIVIDUALS. THE ROLE OF REWARD GENETIC POLYMORPHISMS AND THE EPIGENETIC MODIFICATIONS THAT LEAD TO VULNERABILITY TO USE AND MISUSE OF OPIATES/OPIOID TO TREAT PAIN ARE REVIEWED. THE NEUROCHEMICAL MECHANISMS OF ACUTE OPIATE WITHDRAWAL AND OPIATE/OPIOID REWARD MECHANISMS ARE EXPLORED WITH A GOAL OF IDENTIFYING SPECIFIC TREATMENT TARGETS. ALTERATIONS IN FUNCTIONAL BRAIN CONNECTIVITY BASED ON NEUROBIOLOGICAL MECHANISMS IN HEROIN DEPENDENCE AND ABSTINENCE ARE ALSO REVIEWED. A NEW CLINICAL MODEL AN ALTERNATIVE TO MERELY BLOCKING ACUTE WITHDRAWAL SYMPTOMS AS IDENTIFIED IN THE DSM -5 IS PROPOSED. GENETIC DIAGNOSIS AT THE ONSET OF DETOXIFICATION, TO DETERMINE RISK STRATIFICATION, AND IDENTIFY POLYMORPHIC GENE TARGETS FOR PHARMACEUTICAL AND NUTRACEUTICAL INTERVENTIONS, FOLLOWED BY THE SIMULTANEOUS INITIATION OF MEDICATION ASSISTED THERAPY (MAT), TO ENABLE PSYCHOLOGICAL EXTINCTION, AND STEADY PRO-DOPAMINERGIC THERAPY WITH THE GOAL OF DEVELOPING "DOPAMINE HOMEOSTASIS" IS RECOMMENDED. THE OBJECTIVE OF THESE INTERVENTIONS IS TO PREVENT FUTURE RELAPSE BY TREATING ALL "REWARD DEFICIENCY SYNDROME" (RDS) BEHAVIORS AND EVENTUALLY MAKE AN ADDICTION-FREE LIFE POSSIBLE. 2017 7 1984 29 EPIGENETIC ALTERATIONS IN PRESCRIPTION OPIOID MISUSE: NEW STRATEGIES FOR PRECISION PAIN MANAGEMENT. PRESCRIPTION OPIOIDS ARE USED FOR SOME CHRONIC PAIN CONDITIONS. HOWEVER, GENERALLY, LONG-TERM THERAPY HAS UNWANTED SIDE EFFECTS WHICH MAY TRIGGER ADDICTION, OVERDOSE, AND EVENTUALLY CAUSE DEATHS. OPIOID ADDICTION AND CHRONIC PAIN CONDITIONS HAVE BOTH BEEN ASSOCIATED WITH EVIDENCE OF GENETIC AND EPIGENETIC ALTERATIONS. DESPITE INTENSE RESEARCH INTEREST, MANY QUESTIONS ABOUT THE CONTRIBUTION OF EPIGENETIC CHANGES TO THIS TYPOLOGY OF ADDICTION VULNERABILITY AND DEVELOPMENT REMAIN UNANSWERED. THE AIM OF THIS REVIEW WAS TO SUMMARIZE THE EPIGENETIC MODIFICATIONS DETECTED IN SPECIFIC TISSUES OR BRAIN AREAS AND ASSOCIATED WITH OPIOID PRESCRIPTION AND MISUSE IN PATIENTS WHO HAVE INITIATED PRESCRIBED OPIOID MANAGEMENT FOR CHRONIC NON-CANCER PAIN. THE REVIEW CONSIDERS THE EFFECTS OF OPIOID EXPOSURE ON THE EPIGENOME IN CENTRAL AND PERIPHERAL TISSUES IN ANIMAL MODELS AND HUMAN SUBJECTS AND HIGHLIGHTS THE MECHANISMS IN WHICH OPIOID EPIGENETICS MAY BE INVOLVED. THIS WILL IMPROVE OUR CURRENT UNDERSTANDING, PROVIDE THE BASIS FOR TARGETED, PERSONALIZED PAIN MANAGEMENT, AND THUS BALANCE OPIOID RISKS AND BENEFITS IN MANAGING CHRONIC PAIN. 2021 8 2586 31 EPIGENETICS OF PAIN MEDIATORS. PURPOSE OF REVIEW: THE FIELD OF EPIGENETICS CONTINUES ITS INFLUENTIAL RISE AS A MEANS TO BETTER UNDERSTAND AN ORGANISM'S UNIQUE DEVELOPMENTAL IDENTITY OVER A LIFESPAN. WHEREAS A GENOME IS CONSTANT AND UNCHANGING, AN EPIGENOME IS DYNAMIC AND ALTERABLE. EPIGENETIC CHANGES ARE IN RESPONSE TO INNUMERABLE INTERNAL AND EXTERNAL INFLUENCES INCLUDING ENVIRONMENTAL CHANGES SUCH AS DIET, EXERCISE, DISEASE, TOXINS, AND STRESS. EPIGENETICS IS OF PARTICULAR INTEREST IN THE MEDICAL RESEARCH COMMUNITY BOTH FOR THE POTENTIAL TO CAUSE DISEASE AND AS A TARGET FOR THERAPEUTIC INTERVENTIONS. THIS ARTICLE PROVIDES A SUCCINCT EXPLANATION OF THE POTENTIAL FOR EPIGENETICS TO INFLUENCE THE UNDERSTANDING OF PAIN AS WELL AS A REVIEW OF RELEVANT RESEARCH ON THE TOPIC. RECENT FINDINGS: STUDIES ON EPIGENETICS AND PAIN REMAIN LARGELY PRECLINICAL AND INVESTIGATE THE THEORETICAL ABILITY OF EPIGENETICS TO ALTER THE NOCICEPTIVE PATHWAYS BOTH IN THE PERIPHERY AND CENTRALLY. SIGNIFICANT EVIDENCE NOW EXISTS FOR THE ABILITY OF EPIGENETICS TO MODIFY BROADLY CATEGORIZED PAIN TYPES, INCLUDING INFLAMMATORY, NEUROPATHIC, VISCERAL, AND CANCER RELATED. SUMMARY: BOTH PATIENTS AND PROVIDERS RECOGNIZE THAT NOVEL MEDICATIONS FOR THE TREATMENT OF BOTH ACUTE AND CHRONIC PAIN CONDITIONS ARE SORELY NEEDED. THE UNDERSTANDING OF EPIGENETICS AND ITS INFLUENCE ON NOCICEPTION REMAINS IN RELATIVE INFANCY BUT EARLY EVIDENCE IS STRONG FOR POTENTIAL THERAPEUTIC BENEFITS TO TREAT THESE CONDITIONS. 2018 9 6226 20 THE LINK BETWEEN EPIGENETICS, PAIN SENSITIVITY AND CHRONIC PAIN. INCREASING EVIDENCE SUGGESTS AN ASSOCIATION BETWEEN GENE EXPRESSION AND CLINICAL PAIN. EPIGENETIC MODIFICATIONS ARE THE MAIN MODULATORS OF GENE EXPRESSION OR PROTEIN TRANSLATION IN RESPONSE TO ENVIRONMENTAL STIMULI AND PATHOPHYSIOLOGICAL CONDITIONS. PRECLINICAL AND CLINICAL STUDIES INDICATE THAT EPIGENETIC MODIFICATIONS COULD ALSO IMPACT THE DEVELOPMENT OF PAIN, THE TRANSITION FROM ACUTE TO CHRONIC PAIN, AND THE MAINTENANCE HEREOF. 2022 10 1686 43 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 11 1676 35 DRUG ADDICTION: FROM BENCH TO BEDSIDE. DRUG ADDICTION IS RESPONSIBLE FOR MILLIONS OF DEATHS PER YEAR AROUND THE WORLD. STILL, ITS MANAGEMENT AS A CHRONIC DISEASE IS SHADOWED BY MISCONCEPTIONS FROM THE GENERAL PUBLIC. INDEED, DRUG CONSUMERS ARE OFTEN LABELLED AS "WEAK", "IMMORAL" OR "DEPRAVED". CONSEQUENTLY, DRUG ADDICTION IS OFTEN PERCEIVED AS AN INDIVIDUAL PROBLEM AND NOT SOCIETAL. IN TECHNICAL TERMS, DRUG ADDICTION IS DEFINED AS A CHRONIC, RELAPSING DISEASE RESULTING FROM SUSTAINED EFFECTS OF DRUGS ON THE BRAIN. THROUGH A BETTER CHARACTERISATION OF THE CEREBRAL CIRCUITS INVOLVED, AND THE LONG-TERM MODIFICATIONS OF THE BRAIN INDUCED BY ADDICTIVE DRUGS ADMINISTRATIONS, FIRST, WE MIGHT BE ABLE TO CHANGE THE WAY THE GENERAL PUBLIC SEE THE PATIENT WHO IS SUFFERING FROM DRUG ADDICTION, AND SECOND, WE MIGHT BE ABLE TO FIND NEW TREATMENTS TO NORMALISE THE ALTERED BRAIN HOMEOSTASIS. IN THIS REVIEW, WE SYNTHETISE THE CONTRIBUTION OF FUNDAMENTAL RESEARCH TO THE UNDERSTANDING DRUG ADDICTION AND ITS CONTRIBUTION TO POTENTIAL NOVEL THERAPEUTICS. MOSTLY BASED ON DRUG-INDUCED MODIFICATIONS OF SYNAPTIC PLASTICITY AND EPIGENETIC MECHANISMS (AND THEIR BEHAVIOURAL CORRELATES) AND AFTER DEMONSTRATION OF THEIR REVERSIBILITY, WE TRIED TO HIGHLIGHT PROMISING THERAPEUTICS. WE ALSO UNDERLINE THE SPECIFIC TEMPORAL DYNAMICS AND PSYCHOSOCIAL ASPECTS OF THIS COMPLEX PSYCHIATRIC DISEASE ADDING PARAMETERS TO BE CONSIDERED IN CLINICAL TRIALS AND PAVING THE WAY TO TEST NEW THERAPEUTIC VENUES. 2021 12 2611 34 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 13 2993 29 GENETIC PAIN LOSS DISORDERS. GENETIC PAIN LOSS INCLUDES CONGENITAL INSENSITIVITY TO PAIN (CIP), HEREDITARY SENSORY NEUROPATHIES AND, IF AUTONOMIC NERVES ARE INVOLVED, HEREDITARY SENSORY AND AUTONOMIC NEUROPATHY (HSAN). THIS HETEROGENEOUS GROUP OF DISORDERS HIGHLIGHTS THE ESSENTIAL ROLE OF NOCICEPTION IN PROTECTING AGAINST TISSUE DAMAGE. PATIENTS WITH GENETIC PAIN LOSS HAVE RECURRENT INJURIES, BURNS AND POORLY HEALING WOUNDS AS DISEASE HALLMARKS. CIP AND HSAN ARE CAUSED BY PATHOGENIC GENETIC VARIANTS IN >20 GENES THAT LEAD TO DEVELOPMENTAL DEFECTS, NEURODEGENERATION OR ALTERED NEURONAL EXCITABILITY OF PERIPHERAL DAMAGE-SENSING NEURONS. THESE GENETIC VARIANTS LEAD TO HYPERACTIVITY OF SODIUM CHANNELS, DISTURBED HAEM METABOLISM, ALTERED CLATHRIN-MEDIATED TRANSPORT AND IMPAIRED GENE REGULATORY MECHANISMS AFFECTING EPIGENETIC MARKS, LONG NON-CODING RNAS AND REPETITIVE ELEMENTS. THERAPIES FOR PAIN LOSS DISORDERS ARE MAINLY SYMPTOMATIC BUT THE FIRST TARGETED THERAPIES ARE BEING TESTED. CONVERSELY, CHRONIC PAIN REMAINS ONE OF THE GREATEST UNRESOLVED MEDICAL CHALLENGES, AND THE GENES AND MECHANISMS ASSOCIATED WITH PAIN LOSS OFFER NEW TARGETS FOR ANALGESICS. GIVEN THE PROGRESS THAT HAS BEEN MADE, THE COMING YEARS ARE PROMISING BOTH IN TERMS OF TARGETED TREATMENTS FOR PAIN LOSS DISORDERS AND THE DEVELOPMENT OF INNOVATIVE PAIN MEDICINES BASED ON KNOWLEDGE OF THESE GENETIC DISEASES. 2022 14 5447 35 REPOSITIONING LIDOCAINE AS AN ANTICANCER DRUG: THE ROLE BEYOND ANESTHESIA. WHILE CANCER TREATMENT HAS IMPROVED DRAMATICALLY, IT HAS ALSO ENCOUNTERED MANY CRITICAL CHALLENGES, SUCH AS DISEASE RECURRENCE, METASTASIS, AND DRUG RESISTANCE, MAKING NEW DRUGS WITH NOVEL MECHANISMS AN URGENT CLINICAL NEED. THE TERM "DRUG REPOSITIONING," ALSO KNOWN AS OLD DRUGS FOR NEW USES, HAS EMERGED AS ONE PRACTICAL STRATEGY TO DEVELOP NEW ANTICANCER DRUGS. ANESTHETICS HAVE BEEN WIDELY USED IN SURGICAL PROCEDURES TO REDUCE THE EXCRUCIATING PAIN. LIDOCAINE, ONE OF THE MOST-USED LOCAL ANESTHETICS IN CLINICAL SETTINGS, HAS BEEN FOUND TO SHOW MULTI-ACTIVITIES, INCLUDING POTENTIAL IN CANCER TREATMENT. GROWING EVIDENCE SHOWS THAT LIDOCAINE MAY NOT ONLY WORK AS A CHEMOSENSITIZER THAT SENSITIZES OTHER CONVENTIONAL CHEMOTHERAPEUTICS TO CERTAIN RESISTANT CANCER CELLS, BUT ALSO COULD SUPPRESS CANCER CELLS GROWTH BY SINGLE USE AT DIFFERENT DOSES OR CONCENTRATIONS. LIDOCAINE COULD SUPPRESS CANCER CELL GROWTH IN VITRO AND IN VIVO VIA MULTIPLE MECHANISMS, SUCH AS REGULATING EPIGENETIC CHANGES AND PROMOTING PRO-APOPTOSIS PATHWAYS, AS WELL AS REGULATING ABC TRANSPORTERS, METASTASIS, AND ANGIOGENESIS, ETC., PROVIDING VALUABLE INFORMATION FOR ITS FURTHER APPLICATION IN CANCER TREATMENT AND FOR NEW DRUG DISCOVERY. IN ADDITION, LIDOCAINE IS NOW UNDER CLINICAL TRIALS TO TREAT CERTAIN TYPES OF CANCER. IN THE CURRENT REVIEW, WE SUMMARIZE THE RESEARCH AND ANALYZE THE UNDERLYING MECHANISMS, AND ADDRESS KEY ISSUES IN THIS AREA. 2020 15 6846 34 [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 16 3418 34 HUMAN HEALTH CONSEQUENCES OF ENVIRONMENTALLY-MODULATED GENE EXPRESSION: POTENTIAL ROLES OF ELF-EMF INDUCED EPIGENETIC VERSUS MUTAGENIC MECHANISMS OF DISEASE. IN ORDER TO DETERMINE IF THERE MIGHT BE BIOLOGICAL AND HEALTH CONSEQUENCES AFTER EXPOSURES TO EXTREMELY-LOW FREQUENCY ELECTROMAGNETIC FIELDS (ELF-EMF), EITHER EXPERIMENTALLY OR EPIDEMIOLOGICALLY, MECHANISTIC UNDERSTANDING OF THE POTENTIAL MEANS BY WHICH ANY ENVIRONMENTAL AGENT CAN AFFECT CELLS IN A MULTICELLULAR ORGANISM HAS TO BE REVIEWED. THE GOAL OF THIS LIMITED REVIEW IS TO DEMONSTRATE THAT, WHILE THE PREVAILING PARADIGM OF THE ENVIRONMENTALLY-INDUCED ACUTE AND CHRONIC DISEASES INVOLVES EITHER CELL KILLING (CYTOTOXICITY) OR GENE/CHROMOSOME MUTATIONS (GENOTOXICITY), ALTERATION OF THE EXPRESSION OF GENETIC INFORMATION AT THE TRANSCRIPTIONAL (TURNING GENES "ON" OR "OFF"), TRANSLATIONAL (STABILIZING OR DE-STABILIZING THE GENETIC MESSAGE), OR POSTTRANSLATIONAL (ALTERING THE GENE PRODUCT OR PROTEIN) LEVELS HAS THE POTENTIAL TO CONTRIBUTE TO VARIOUS DISEASES. THIS LATTER MECHANISM, "EPIGENETIC" TOXICITY, UNLIKE THE FORMER TWO WHICH ARE IRREVERSIBLE, IS CHARACTERIZED BY THRESHOLD-LIKE ACTION, MULTIPLE BIOCHEMICAL PATHWAYS AND CHRONIC, REGULAR EXPOSURES TO BE EFFECTIVE. ULTIMATELY, EPIGENETIC TOXICANTS AFFECT ONE OF FOUR POTENTIAL CELL STATES, NAMELY ALTERATION OF CELL PROLIFERATION, CELL DIFFERENTIATION, PROGRAMMED CELL DEATH (APOPTOSIS) OR ADAPTIVE RESPONSES OF DIFFERENTIATED CELLS. 2000 17 789 35 CELLULAR AND MOLECULAR MECHANISMS DRIVING NEUROPATHIC PAIN: RECENT ADVANCEMENTS AND CHALLENGES. CURRENT PHARMACOTHERAPEUTICS FOR NEUROPATHIC PAIN OFFER ONLY SYMPTOMATIC RELIEF WITHOUT TREATING THE UNDERLYING PATHOPHYSIOLOGY. ADDITIONALLY, THEY ARE ASSOCIATED WITH VARIOUS DOSE-LIMITING SIDE EFFECTS. PAIN RESEARCH IN THE PAST FEW DECADES HAS REVOLVED AROUND THE ROLE OF OXIDATIVE-NITROSATIVE STRESS, PROTEIN KINASES, GLIAL CELL ACTIVATION, AND INFLAMMATORY SIGNALING CASCADES BUT HAS FAILED TO PRODUCE SPECIFIC AND EFFECTIVE THERAPIES. AREAS COVERED: THIS REVIEW FOCUSES ON RECENT ADVANCES IN CELLULAR AND MOLECULAR MECHANISMS OF NEUROPATHIC PAIN THAT MAY BE TRANSLATED INTO FUTURE THERAPIES. WE DISCUSS EMERGING TARGETS SUCH AS WNT SIGNALING MECHANISMS, THE TETRAHYDROBIOPTERIN PATHWAY, MRG RECEPTORS, ENDOGENOUS LIPID MEDIATORS, MICRO-RNAS AND THEIR ROLES IN PAIN REGULATION. RECENT EVIDENCE IS ALSO PRESENTED REGARDING GENETIC AND EPIGENETIC MECHANISMS OF PAIN MODULATION. EXPERT OPINION: DURING CHRONIC NEUROPATHIC PAIN, MALADAPTATION OCCURS IN THE PERIPHERAL AND CENTRAL NERVOUS SYSTEMS, INCLUDING A SHIFT IN MICROGLIAL PHENOTYPE FROM A SURVEILLANCE STATE TO AN ACTIVATED STATE. MICROGLIAL ACTIVATION LEADS TO AN ALTERED EXPRESSION OF CELL SURFACE PROTEINS, GROWTH FACTORS, AND INTRACELLULAR SIGNALING MOLECULES THAT CONTRIBUTE TO DEVELOPMENT OF A NEUROINFLAMMATORY CASCADE AND CHRONIC PAIN SENSITIZATION. SPECIFIC TARGETING OF THESE CELLULAR AND MOLECULAR MECHANISMS MAY PROVIDE THE KEY TO DEVELOPMENT OF EFFECTIVE NEUROPATHIC PAIN THERAPIES THAT HAVE MINIMAL SIDE EFFECTS. 2018 18 2551 44 EPIGENETICS IN PAIN AND ANALGESIA: AN IMMINENT RESEARCH FIELD. HERITABLE PHENOTYPES RESULTING FROM ENVIRONMENT-CAUSED CHANGES IN A CHROMOSOME WITHOUT ALTERATIONS IN THE DNA SEQUENCE ARE INCREASINGLY RECOGNIZED AS A BASIS OF PERSONALIZED THERAPY. EPIGENETIC MECHANISMS INCLUDE COVALENT MODIFICATIONS OF THE DNA (METHYLATION) OR OF THE DNA-PACKAGING HISTONES (E.G., DEACETYLATION OR PHOSPHORYLATION). IN ADDITION, REGULATORY NON-CODING RNA MOLECULES (MICRO-RNAS) EXERT EPIGENETIC ACTIONS. THIS LEADS TO DISRUPTION OR OTHERWISE MODIFIED EXPRESSION OF GENES. ENVIRONMENTAL INFLUENCES SUCH AS NUTRITIONAL FACTORS, EXPOSURE TO CHEMICALS OR DRUGS, BUT ALSO SOCIAL FACTORS APPEAR TO EXERT EPIGENETIC ACTIONS. HISTONE MODIFICATIONS AND DNA METHYLATION ARE ASSOCIATED WITH THE SUBJECT'S AGE. EPIGENETIC MECHANISMS CAN SILENCE THE EXPRESSION OF PRO- OR ANTINOCICEPTIVE GENES. TO THE EPIGENETIC CONTROL OF NOCICEPTION ADDS ITS CONTROL OF THE PHARMACODYNAMICS OR PHARMACOKINETICS OF ANALGESICS BY EPIGENETIC CONTROL OF DRUG TARGETS AND ANALGESICS METABOLIZING ENZYMES. ALTHOUGH EPIGENETICS-BASED STRATEGIES FOR PAIN THERAPY ARE NOT YET AVAILABLE, EXPERIMENTS IN RODENTS SUGGEST THAT RNA INTERFERENCE MAY BECOME A NEW THERAPY APPROACH FOR NEUROPATHIC AND OTHER PAIN. ANOTHER EPIGENETIC APPROACH TO ANALGESIC TREATMENT EMPLOYS INHIBITORS OF HISTONE DEACETYLASE THAT ACT ON THE EPIGENOME BY INDIRECTLY REMODELING THE SPATIAL CONFORMATION OF THE CHROMATIN. FINALLY, EPIGENETIC TECHNIQUES SUCH AS RNA INTERFERENCE HAVE BEEN EMPLOYED IN PAIN RESEARCH TO PROOF THE CONTRIBUTION OF CERTAIN PROTEINS TO NOCICEPTION. THUS, THE NEW FIELD OF EPIGENETICS BECOMES INCREASINGLY USED IN RESEARCH AND MANAGEMENT OF PAIN AND WILL COMPLEMENT GENETICS. THIS ARTICLE INTRODUCES EPIGENETICS TO PAIN AND SUMMARIZES THE CURRENT AND FUTURE UTILITY. 2011 19 2000 28 EPIGENETIC AND NON-CODING REGULATION OF ALCOHOL ABUSE AND ADDICTION. ALCOHOL USE DISORDER IS A CHRONIC DEBILITATED CONDITION ADVERSELY AFFECTING THE LIVES OF MILLIONS OF INDIVIDUALS THROUGHOUT THE MODERN WORLD. INDIVIDUALS SUFFERING FROM AN ALCOHOL USE DISORDER DIAGNOSIS FREQUENTLY HAVE SERIOUS COOCCURRING CONDITIONS, WHICH OFTEN FURTHER EXACERBATES PROBLEMATIC DRINKING BEHAVIOR. COMPREHENDING THE BIOCHEMICAL PROCESSES UNDERLYING THE PROGRESSION AND PERPETUATION OF DISEASE IS ESSENTIAL FOR MITIGATING MALADAPTIVE BEHAVIOR IN ORDER TO RESTORE BOTH PHYSIOLOGICAL AND PSYCHOLOGICAL HEALTH. THE RANGE OF CELLULAR AND BIOLOGICAL SYSTEMS CONTRIBUTING TO, AND AFFECTED BY, ALCOHOL USE DISORDER AND OTHER COMORBID DISORDERS NECESSITATES A FUNDAMENTAL GRASP OF INTRICATE FUNCTIONAL RELATIONSHIPS THAT GOVERN MOLECULAR BIOLOGY. EPIGENETIC FACTORS ARE RECOGNIZED AS ESSENTIAL MEDIATORS OF CELLULAR BEHAVIOR, ORCHESTRATING A SYMPHONY OF GENE EXPRESSION CHANGES WITHIN MULTICELLULAR ENVIRONMENTS THAT ARE ULTIMATELY RESPONSIBLE FOR DIRECTING HUMAN BEHAVIOR. UNDERSTANDING THE EPIGENETIC AND TRANSCRIPTIONAL REGULATORY MECHANISMS INVOLVED IN THE PATHOGENESIS OF DISEASE IS IMPORTANT FOR IMPROVING AVAILABLE PHARMACOTHERAPIES AND REDUCING THE INCIDENCE OF ALCOHOL ABUSE AND COOCCURRING CONDITIONS. 2021 20 1688 29 DUAL BET/HDAC INHIBITION TO RELIEVE NEUROPATHIC PAIN: RECENT ADVANCES, PERSPECTIVES, AND FUTURE OPPORTUNITIES. DESPITE THE INTENSE RESEARCH ON DEVELOPING NEW THERAPIES FOR NEUROPATHIC PAIN STATES, AVAILABLE TREATMENTS HAVE LIMITED EFFICACY AND UNFAVORABLE SAFETY PROFILES. EPIGENETIC ALTERATIONS HAVE A GREAT INFLUENCE ON THE DEVELOPMENT OF CANCER AND NEUROLOGICAL DISEASES, AS WELL AS NEUROPATHIC PAIN. HISTONE ACETYLATION HAS PREVAILED AS ONE OF THE WELL INVESTIGATED EPIGENETIC MODIFICATIONS IN THESE DISEASES. ALTERED SPINAL ACTIVITY OF HISTONE DEACETYLASE (HDAC) AND BROMO AND EXTRA TERMINAL DOMAIN (BET) HAVE BEEN DESCRIBED IN NEUROPATHIC PAIN MODELS AND RESTORATION OF THESE ABERRANT EPIGENETIC MODIFICATIONS SHOWED PAIN-RELIEVING ACTIVITY. OVER THE LAST DECADES HDACS AND BETS HAVE BEEN THE FOCUS OF DRUG DISCOVERY STUDIES, LEADING TO THE DEVELOPMENT OF NUMEROUS SMALL-MOLECULE INHIBITORS. CLINICAL TRIALS TO EVALUATE THEIR ANTICANCER ACTIVITY SHOWED GOOD EFFICACY BUT RAISED TOXICITY CONCERNS THAT LIMITED TRANSLATION TO THE CLINIC. TO MAXIMIZE ACTIVITY AND MINIMIZE TOXICITY, THESE COMPOUNDS CAN BE APPLIED IN COMBINATION OF SUB-MAXIMAL DOSES TO PRODUCE ADDITIVE OR SYNERGISTIC INTERACTIONS (COMBINATION THERAPY). RECENTLY, OF PARTICULAR INTEREST, DUAL BET/HDAC INHIBITORS (MULTI-TARGET DRUGS) HAVE BEEN DEVELOPED TO ASSURE SIMULTANEOUS MODULATION OF BET AND HDAC ACTIVITY BY A SINGLE MOLECULE. THIS REVIEW WILL SUMMARIZE THE MOST RECENT ADVANCES WITH THESE STRATEGIES, DESCRIBING ADVANTAGES AND LIMITATIONS OF SINGLE DRUG TREATMENT VS COMBINATION REGIMENS. THIS REVIEW WILL ALSO PROVIDE A FOCUS ON DUAL BET/HDAC DRUG DISCOVERY INVESTIGATIONS AS FUTURE THERAPEUTIC OPPORTUNITY FOR HUMAN THERAPY OF NEUROPATHIC PAIN. 2021