1 1880 153 EMERGING STRATEGIES TO DISRUPT THE CENTRAL TGF-BETA AXIS IN KIDNEY FIBROSIS. CHRONIC KIDNEY DISEASE (CKD) AFFECTS MORE THAN 20 MILLION PEOPLE IN THE UNITED STATES AND THE GLOBAL BURDEN OF THIS DISORDER IS INCREASING. MANY AFFECTED INDIVIDUALS WILL PROGRESS TO END STAGE KIDNEY DISEASE NECESSITATING DIALYSIS OR TRANSPLANTATION. CKD IS ALSO A MAJOR INDEPENDENT CONTRIBUTOR TO THE RISK OF CARDIOVASCULAR MORBIDITY AND MORTALITY. TUBULOINTERSTITIAL FIBROSIS IS A FINAL COMMON PATHWAY FOR MOST CAUSES OF PROGRESSIVE CKD. CURRENTLY, THERE ARE NO CLINICALLY AVAILABLE THERAPIES TARGETING FIBROSIS THAT CAN SLOW THE DECLINE IN KIDNEY FUNCTION. ALTHOUGH IT HAS LONG BEEN KNOWN THAT TGF-BETA SIGNALING IS A CRITICAL MEDIATOR OF KIDNEY FIBROSIS, TRANSLATING THIS KNOWLEDGE TO THE CLINIC HAS BEEN CHALLENGING. IN THIS REVIEW, WE HIGHLIGHT SOME RECENT INSIGHTS INTO THE MECHANISMS OF TGF-BETA SIGNALING THAT TARGET ACTIVATION OF THIS CYTOKINE AT THE SITE OF INJURY OR SELECTIVELY INHIBIT PRO-FIBROTIC GENE EXPRESSION. MOLECULES DIRECTED AT THESE TARGETS HOLD THE PROMISE OF ATTAINING THERAPEUTIC EFFICACY WHILE LIMITING TOXICITY SEEN WITH GLOBAL INHIBITION OF TGF-BETA. KIDNEY INJURY HAS PROFOUND EPIGENETIC EFFECTS LEADING TO ALTERED EXPRESSION OF MORE THAN A THOUSAND GENES. WE DISCUSS HOW DRUGS TARGETING EPIGENETIC MODIFICATIONS, SOME OF WHICH ARE IN USE FOR CANCER THERAPY, HAVE THE POTENTIAL TO REPROGRAM GENE REGULATORY NETWORKS TO FAVOR ADAPTIVE REPAIR AND PREVENT FIBROSIS. THE LACK OF RELIABLE BIOMARKERS OF KIDNEY FIBROSIS IS A MAJOR LIMITATION IN DESIGNING CLINICAL TRIALS FOR TESTING CKD TREATMENTS. WE CONCLUDE BY REVIEWING RECENT ADVANCES IN FIBROSIS BIOMARKER DEVELOPMENT. 2019 2 5950 35 TARGETING THE PROGRESSION OF CHRONIC KIDNEY DISEASE. CHRONIC KIDNEY DISEASE (CKD) IS A DEVASTATING CONDITION THAT IS REACHING EPIDEMIC LEVELS OWING TO THE INCREASING PREVALENCE OF DIABETES MELLITUS, HYPERTENSION AND OBESITY, AS WELL AS AGEING OF THE POPULATION. REGARDLESS OF THE UNDERLYING AETIOLOGY, CKD IS SLOWLY PROGRESSIVE AND LEADS TO IRREVERSIBLE NEPHRON LOSS, END-STAGE RENAL DISEASE AND/OR PREMATURE DEATH. FACTORS THAT CONTRIBUTE TO CKD PROGRESSION INCLUDE PARENCHYMAL CELL LOSS, CHRONIC INFLAMMATION, FIBROSIS AND REDUCED REGENERATIVE CAPACITY OF THE KIDNEY. CURRENT THERAPIES HAVE LIMITED EFFECTIVENESS AND ONLY DELAY DISEASE PROGRESSION, UNDERSCORING THE NEED TO DEVELOP NOVEL THERAPEUTIC APPROACHES TO EITHER STOP OR REVERSE PROGRESSION. PRECLINICAL STUDIES HAVE IDENTIFIED SEVERAL APPROACHES THAT REDUCE FIBROSIS IN EXPERIMENTAL MODELS, INCLUDING TARGETING CYTOKINES, TRANSCRIPTION FACTORS, DEVELOPMENTAL AND SIGNALLING PATHWAYS AND EPIGENETIC MODULATORS, PARTICULARLY MICRORNAS. SOME OF THESE NEPHROPROTECTIVE STRATEGIES ARE NOW BEING TESTED IN CLINICAL TRIALS. LESSONS LEARNED FROM THE FAILURE OF CLINICAL STUDIES OF TRANSFORMING GROWTH FACTOR BETA1 (TGFBETA1) BLOCKADE UNDERSCORE THE NEED FOR ALTERNATIVE APPROACHES TO CKD THERAPY, AS STRATEGIES THAT TARGET A SINGLE PATHOGENIC PROCESS MAY RESULT IN UNEXPECTED NEGATIVE EFFECTS ON SIMULTANEOUSLY OCCURRING PROCESSES. ADDITIONAL PROMISING AVENUES INCLUDE PREVENTING TUBULAR CELL INJURY AND ANTI-FIBROTIC THERAPIES THAT TARGET ACTIVATED MYOFIBROBLASTS, THE MAIN COLLAGEN-PRODUCING CELLS. 2020 3 2211 37 EPIGENETIC MODIFICATIONS AND THE DEVELOPMENT OF KIDNEY GRAFT FIBROSIS. PURPOSE OF REVIEW: TO OUTLINE RECENT DISCOVERIES IN EPIGENETIC REGULATORY MECHANISMS THAT HAVE POTENTIAL IMPLICATIONS IN THE DEVELOPMENT OF RENAL FIBROSIS FOLLOWING KIDNEY TRANSPLANTATION. RECENT FINDINGS: THE CHARACTERIZATION OF RENAL FIBROSIS FOLLOWING KIDNEY TRANSPLANTATION HAS SHOWN TGFBETA/SMAD SIGNALING TO PLAY A MAJOR ROLE IN THE PROGRESSION TO CHRONIC ALLOGRAFT DYSFUNCTION. THE ONSET OF UNREGULATED PROINFLAMMATORY PATHWAYS ARE ONLY EXACERBATED BY THE DECLINE IN REGULATORY MECHANISMS LOST WITH PROGRESSIVE PATIENT AGE AND COMORBIDITIES SUCH AS HYPERTENSION AND DIABETES. HOWEVER, SIGNIFICANT DEVELOPMENTS IN THE RECOGNITION OF EPIGENETIC REGULATORY MARKERS UPSTREAM OF ABERRANT TGFBETA-SIGNALING HAS SIGNIFICANT CLINICAL POTENTIAL TO PROVIDE THERAPEUTIC TARGETS FOR THE TREATMENT OF RENAL FIBROSIS. IN ADDITION, DISCOVERIES IN EXTRACELLULAR VESICLES AND THE CHARACTERIZATION OF THEIR CARGO HAS LAID NEW FRAMEWORK FOR THE POTENTIAL TO EVALUATE PATIENT OUTCOMES INDEPENDENT OF INVASIVE BIOPSIES. SUMMARY: THE CURRENT REVIEW SUMMARIZES THE MAIN FINDINGS IN EPIGENETIC MACHINERY SPECIFIC TO THE DEVELOPMENT OF RENAL FIBROSIS AND HIGHLIGHTS THERAPEUTIC OPTIONS THAT HAVE SIGNIFICANT POTENTIAL TO TRANSLATE INTO CLINICAL PRACTICE. 2021 4 5258 38 PROGRESSION OF TUBULOINTERSTITIAL FIBROSIS AND THE CHRONIC KIDNEY DISEASE PHENOTYPE - ROLE OF RISK FACTORS AND EPIGENETICS. ALTHOUGH THE KIDNEY HAS CAPACITY TO REPAIR AFTER MILD INJURY, ONGOING OR SEVERE DAMAGE RESULTS IN SCARRING (FIBROSIS) AND AN ASSOCIATED PROGRESSIVE LOSS OF KIDNEY FUNCTION. HOWEVER, DESPITE ITS UNIVERSAL SIGNIFICANCE, EVIDENCE HIGHLIGHTS A POPULATION BASED HETEROGENEITY IN THE TRAJECTORY OF CHRONIC KIDNEY DISEASE (CKD) IN THESE PATIENTS. TO EXPLAIN THE HETEROGENEITY OF THE CKD PHENOTYPE REQUIRES AN UNDERSTANDING OF THE RELEVANT RISK FACTORS FOR FIBROSIS. THESE FACTORS INCLUDE BOTH THE EXTRINSIC NATURE OF INJURY, AND INTRINSIC FACTORS SUCH AS AGE, GENDER, GENETICS, AND PERPETUAL ACTIVATION OF FIBROBLASTS THROUGH PRIMING. IN MANY CASES AN ADDITIONAL LEVEL OF REGULATION IS PROVIDED BY EPIGENETIC MECHANISMS WHICH INTEGRATE THE VARIOUS PRO-FIBROTIC AND ANTI-FIBROTIC TRIGGERS IN FIBROGENESIS. IN THIS REVIEW WE THEREFORE EXAMINE THE VARIOUS MOLECULAR AND STRUCTURAL CHANGES OF FIBROSIS, AND HOW THEY ARE INFLUENCED BY EXTRINSIC AND INTRINSIC FACTORS. OUR AIM IS TO PROVIDE A UNIFYING HYPOTHESIS TO HELP EXPLAIN THE TRANSITION FROM ACUTE TO CKD. 2017 5 2286 31 EPIGENETIC REGULATION IN KIDNEY TRANSPLANTATION. KIDNEY TRANSPLANTATION IS A STANDARD CARE FOR END STAGE RENAL DISEASE, BUT IT IS ALSO ASSOCIATED WITH A COMPLEX PATHOGENESIS INCLUDING ISCHEMIA-REPERFUSION INJURY, INFLAMMATION, AND DEVELOPMENT OF FIBROSIS. OVER THE PAST DECADE, ACCUMULATING EVIDENCE HAS SUGGESTED A ROLE OF EPIGENETIC REGULATION IN KIDNEY TRANSPLANTATION, INVOLVING DNA METHYLATION, HISTONE MODIFICATION, AND VARIOUS KINDS OF NON-CODING RNAS. HERE, WE ANALYZE THESE RECENT STUDIES SUPPORTING THE ROLE OF EPIGENETIC REGULATION IN DIFFERENT PATHOLOGICAL PROCESSES OF KIDNEY TRANSPLANTATION, I.E., ISCHEMIA-REPERFUSION INJURY, ACUTE REJECTION, AND CHRONIC GRAFT PATHOLOGIES INCLUDING RENAL INTERSTITIAL FIBROSIS. FURTHER INVESTIGATION OF EPIGENETIC ALTERATIONS, THEIR PATHOLOGICAL ROLES AND UNDERLYING MECHANISMS IN KIDNEY TRANSPLANTATION MAY LEAD TO NEW STRATEGIES FOR THE DISCOVERY OF NOVEL DIAGNOSTIC BIOMARKERS AND THERAPEUTIC INTERVENTIONS. 2022 6 5660 43 SEX-SPECIFIC EPIGENETIC PROGRAMMING IN RENAL FIBROSIS AND INFLAMMATION. THE GROWING PREVALENCE OF HYPERTENSION, HEART DISEASE, DIABETES, AND OBESITY ALONG WITH AN AGING POPULATION, IS LEADING TO HIGHER INCIDENCE OF RENAL DISEASES IN THE SOCIETY. CHRONIC KIDNEY DISEASE (CKD) IS CHARACTERIZED MAINLY BY PERSISTENT INFLAMMATION, FIBROSIS, AND GRADUAL LOSS OF RENAL FUNCTION LEADING TO RENAL FAILURE. SEX IS A KNOWN CONTRIBUTOR TO THE DIFFERENCES IN INCIDENCE AND PROGRESSION OF CKD. EPIGENETIC PROGRAMMING IS AN ESSENTIAL REGULATOR OF RENAL PHYSIOLOGY AND IS CRITICALLY INVOLVED IN THE PATHOPHYSIOLOGY OF RENAL INJURY AND FIBROSIS. EPIGENETIC SIGNALING INTEGRATES INTRINSIC AND EXTRINSIC SIGNALS ONTO THE GENOME, AND VARIOUS ENVIRONMENTAL AND HORMONAL STIMULI, INCLUDING SEX HORMONES, WHICH REGULATE GENE EXPRESSION AND DOWNSTREAM CELLULAR RESPONSES. THE MOST EXTENSIVELY STUDIED EPIGENETIC ALTERATIONS THAT PLAY A CRITICAL ROLE IN RENAL DAMAGE INCLUDE HISTONE MODIFICATIONS AND DNA METHYLATION. NOTABLY, THESE EPIGENETIC ALTERATIONS ARE REVERSIBLE, MAKING THEM CANDIDATES FOR POTENTIAL THERAPEUTIC TARGETS FOR THE TREATMENT OF RENAL DISEASES. HERE, WE WILL SUMMARIZE THE CURRENT KNOWLEDGE ON SEX-DIFFERENCES IN EPIGENETIC MODULATION OF RENAL FIBROSIS AND INFLAMMATION AND HIGHLIGHT SOME POSSIBLE EPIGENETIC THERAPEUTIC STRATEGIES FOR CKD TREATMENT. 2023 7 2195 43 EPIGENETIC MODIFICATION MECHANISMS INVOLVED IN INFLAMMATION AND FIBROSIS IN RENAL PATHOLOGY. THE GROWING INCIDENCE OF OBESITY, HYPERTENSION, AND DIABETES, COUPLED WITH THE AGING OF THE POPULATION, IS INCREASING THE PREVALENCE OF RENAL DISEASES IN OUR SOCIETY. CHRONIC KIDNEY DISEASE (CKD) IS CHARACTERIZED BY PERSISTENT INFLAMMATION, FIBROSIS, AND LOSS OF RENAL FUNCTION LEADING TO END-STAGE RENAL DISEASE. NOWADAYS, CKD TREATMENT HAS LIMITED EFFECTIVENESS UNDERSCORING THE IMPORTANCE OF THE DEVELOPMENT OF INNOVATIVE THERAPEUTIC OPTIONS. RECENT STUDIES HAVE IDENTIFIED HOW EPIGENETIC MODIFICATIONS PARTICIPATE IN THE SUSCEPTIBILITY TO CKD AND HAVE EXPLAINED HOW THE ENVIRONMENT INTERACTS WITH THE RENAL CELL EPIGENOME TO CONTRIBUTE TO RENAL DAMAGE. EPIGENETIC MECHANISMS REGULATE CRITICAL PROCESSES INVOLVED IN GENE REGULATION AND DOWNSTREAM CELLULAR RESPONSES. THE MOST RELEVANT EPIGENETIC MODIFICATIONS THAT PLAY A CRITICAL ROLE IN RENAL DAMAGE INCLUDE DNA METHYLATION, HISTONE MODIFICATIONS, AND CHANGES IN MIRNA LEVELS. IMPORTANTLY, THESE EPIGENETIC MODIFICATIONS ARE REVERSIBLE AND, THEREFORE, A SOURCE OF POTENTIAL THERAPEUTIC TARGETS. HERE, WE WILL EXPLAIN HOW EPIGENETIC MECHANISMS MAY REGULATE ESSENTIAL PROCESSES INVOLVED IN RENAL PATHOLOGY AND HIGHLIGHT SOME POSSIBLE EPIGENETIC THERAPEUTIC STRATEGIES FOR CKD TREATMENT. 2018 8 2154 46 EPIGENETIC MECHANISMS AND KIDNEY DISEASES. IN RECENT YEARS, MOLECULAR RESEARCH HAS BROUGHT TO LIGHT A SERIES OF MECHANISMS INVOLVED IN THE REGULATION OF GENE FUNCTION WITHOUT ALTERING THE DNA SEQUENCE. THESE MECHANISMS ARE DESCRIBED WITH THE TERM "EPIGENETICS" AND INCLUDE MODIFICATIONS IN THE STRUCTURE OF THE HUMAN GENOME, LEADING TO HERITABLE AND POTENTIALLY REVERSIBLE CHANGES IN GENE EXPRESSION. THERE IS NOW INCREASING EVIDENCE SUGGESTING THAT SEVERAL CHARACTERISTIC FEATURES OF CHRONIC KIDNEY DISEASE SUCH AS HYPERHOMOCYSTEINEMIA, SUBCLINICAL INFLAMMATION, INCREASED OXIDATIVE STRESS AND OTHERS MAY AFFECT THE HUMAN EPIGENOME. IN ADDITION, ANIMAL STUDIES HAVE SUGGESTED A POSSIBLE LINK BETWEEN NUTRITION AND ENVIRONMENTAL EXPOSURE DURING THE PERICONCEPTIONAL PERIOD AND EPIGENETIC CHANGES IN THE EXPRESSION OF MAJOR GENES IMPLICATED IN KIDNEY ORGANOGENESIS; THESE CHANGES RESULT IN A DIMINISHED NUMBER OF NEPHRONS IN THE DEVELOPING KIDNEY, WHICH PREDISPOSES TO AN INCREASED RISK FOR HYPERTENSION AND CHRONIC KIDNEY DISEASE IN FUTURE LIFE. THE UNDERSTANDING OF THE ROLE OF EPIGENETIC PHENOMENA IN THE PATHOGENESIS OF CHRONIC KIDNEY DISEASE OPENS NEW AVENUES FOR FUTURE THERAPEUTIC STRATEGIES, THROUGH THE DEVELOPMENT OF PHARMACEUTICAL AGENTS THAT TARGET DIRECTLY WITH THE CHANGES IN THE HUMAN EPIGENOME. SUCH EPIGENETIC DRUGS ARE ALREADY IN CLINICAL USE FOR THE TREATMENT OF CANCER AS WELL AS UNDER INVESTIGATION FOR THE USE IN OTHER DISEASES. THIS REVIEW WILL SUMMARIZE THE EXISTING DATA ON THE LINK BETWEEN EPIGENETIC MECHANISMS AND CHRONIC UREMIC MILIEU, AS WELL AS THE PROMISING RESULTS OF ONGOING RESEARCH IN THE FIELD OF EPIGENETIC DRUGS THAT COULD REPRESENT ADDITIONAL OPTIONS IN OUR THERAPEUTIC ARMAMENTARIUM FOR PATIENTS WITH CHRONIC KIDNEY DISEASE. 2011 9 4668 42 NEW INSIGHTS INTO MOLECULAR MECHANISMS OF EPIGENETIC REGULATION IN KIDNEY DISEASE. THE NUMBER OF PATIENTS WITH KIDNEY FAILURE HAS INCREASED IN RECENT YEARS. DIFFERENT FACTORS CONTRIBUTE TO THE PROGRESSION OF CHRONIC KIDNEY DISEASE, INCLUDING GLOMERULAR SCLEROSIS, ATHEROSCLEROSIS OF THE RENAL ARTERIES AND TUBULOINTERSTITIAL FIBROSIS. TUBULOINTERSTITIAL INJURY IS INDUCED BY HYPOXIA AND OTHER INFLAMMATORY SIGNALS, LEADING TO FIBROBLAST ACTIVATION. TECHNOLOGICAL ADVANCES USING HIGH-THROUGHPUT SEQUENCING HAS ENABLED THE DETERMINATION OF THE EXPRESSION PROFILE OF ALMOST ALL GENES, REVEALING THAT GENE EXPRESSION IS INTRICATELY REGULATED BY DNA METHYLATION, HISTONE MODIFICATION, CHANGES IN CHROMOSOME CONFORMATION, LONG NON-CODING RNAS AND MICRORNAS. THESE EPIGENETIC MODIFICATIONS ARE STORED AS CELLULAR EPIGENETIC MEMORY. EPIGENETIC MEMORY LEADS TO ADULT-ONSET DISEASE OR AGEING IN THE LONG TERM AND MAY POSSIBLY PLAY AN IMPORTANT ROLE IN THE KIDNEY DISEASE PROCESS. HEREIN WE EMPHASIZE THE IMPORTANCE OF CLARIFYING THE MOLECULAR MECHANISMS UNDERLYING EPIGENETIC MODIFICATIONS BECAUSE THIS MAY LEAD TO THE DEVELOPMENT OF NEW THERAPEUTIC TARGETS IN KIDNEY DISEASE. 2016 10 97 33 A PRIMER ON THE EPIGENETICS OF KIDNEY FIBROSIS. DESPITE EXTENSIVE KNOWLEDGE OF THE VARIOUS MOLECULAR PATHWAYS THAT CONTRIBUTE TO TUBULOINTERSTITIAL FIBROSIS, IT REMAINS AN UNSOLVED QUESTION WHY THE PROGRESSION RATE OF CHRONIC KIDNEY DISEASE VARIES SUBSTANTIALLY FROM PATIENT TO PATIENT, EVEN AMONG PATIENTS WITH COMMON UNDERLYING NEPHROPATHIES AND COMORBIDITIES. POSSIBLE EXPLANATIONS FOR DIFFERENT SUSCEPTIBILITIES OF INDIVIDUAL PATIENTS TO DEVELOP END-STAGE RENAL FAILURE INCLUDE GENETIC OR EPIGENETIC VARIATIONS, WHICH MODIFY HOW INDIVIDUAL PATIENTS RESPOND TO KIDNEY INJURY. HERE WE REVIEW PRINCIPLES OF EPIGENETIC MECHANISMS IN CONTEXT OF CHRONIC KIDNEY DISEASE AND DISCUSS HOW SUCH INSIGHTS MAY BE UTILIZED FOR FUTURE THERAPEUTIC STRATEGIES AND MAY LEAD TO NOVEL DIAGNOSTIC TOOLS IN THE FUTURE. 2012 11 4882 30 OVERVIEW OF THE CELLULAR AND MOLECULAR BASIS OF KIDNEY FIBROSIS. THE COMMON PATHOGENETIC PATHWAY OF PROGRESSIVE INJURY IN PATIENTS WITH CHRONIC KIDNEY DISEASE (CKD) IS EPITOMIZED AS NORMAL KIDNEY PARENCHYMAL DESTRUCTION DUE TO SCARRING (FIBROSIS). UNDERSTANDING THE FUNDAMENTAL PATHWAYS THAT LEAD TO RENAL FIBROSIS IS ESSENTIAL IN ORDER TO DEVELOP BETTER THERAPEUTIC OPTIONS FOR HUMAN CKD. ALTHOUGH COMPLEX, FOUR CELLULAR RESPONSES ARE PIVOTAL. (1) AN INTERSTITIAL INFLAMMATORY RESPONSE THAT HAS MULTIPLE CONSEQUENCES-SOME HARMFUL AND OTHERS HEALING. (2) THE APPEARANCE OF A UNIQUE INTERSTITIAL CELL POPULATION OF MYOFIBROBLASTS, PRIMARILY DERIVED FROM KIDNEY STROMAL CELLS (FIBROBLASTS AND PERICYTES), THAT ARE THE PRIMARY SOURCE OF THE VARIOUS EXTRACELLULAR MATRIX PROTEINS THAT FORM INTERSTITIAL SCARS. (3) TUBULAR EPITHELIAL CELLS THAT HAVE VARIABLE AND TIME-DEPENDENT ROLES AS EARLY RESPONDERS TO INJURY AND LATER AS VICTIMS OF FIBROSIS DUE TO THE LOSS OF THEIR REGENERATIVE ABILITIES. (4) LOSS OF INTERSTITIAL CAPILLARY INTEGRITY THAT COMPROMISES OXYGEN DELIVERY AND LEADS TO A VICIOUS CASCADE OF HYPOXIA-OXIDANT STRESS THAT ACCENTUATES INJURY AND FIBROSIS. IN THE ABSENCE OF ADEQUATE ANGIOGENIC RESPONSES, A HEALTHY INTERSTITIAL CAPILLARY NETWORK IS NOT MAINTAINED. THE FIBROTIC 'SCAR' THAT TYPIFIES CKD IS AN INTERESTING CONSORTIUM OF MULTIFUNCTIONAL MACROMOLECULES THAT NOT ONLY CHANGE IN COMPOSITION AND STRUCTURE OVER TIME, BUT CAN BE DEGRADED VIA EXTRACELLULAR AND INTRACELLULAR PROTEASES. ALTHOUGH TRANSFORMING GROWTH FACTOR BETA APPEARS TO BE THE PRIMARY DRIVER OF KIDNEY FIBROSIS, A VAST ARRAY OF ADDITIONAL MOLECULES MAY HAVE MODULATING ROLES. THE IMPORTANCE OF GENETIC AND EPIGENETIC FACTORS IS INCREASINGLY APPRECIATED. AN INTRIGUING BUT INCOMPLETELY UNDERSTOOD CARDIORENAL SYNDROME UNDERLIES THE HIGH MORBIDITY AND MORTALITY RATES THAT DEVELOP IN ASSOCIATION WITH PROGRESSIVE KIDNEY FIBROSIS. 2014 12 2982 41 GENETIC CONSIDERATIONS IN PEDIATRIC CHRONIC KIDNEY DISEASE. CHRONIC KIDNEY DISEASE (CKD) IN CHILDREN IS AN IRREVERSIBLE PROCESS THAT, IN SOME CASES, MAY LEAD TO END-STAGE RENAL DISEASE. THE MAJORITY OF CHILDREN WITH CKD HAVE A CONGENITAL DISORDER OF THE KIDNEY OR UROLOGICAL TRACT ARISING FROM BIRTH. THERE IS STRONG EVIDENCE FOR BOTH A GENETIC AND EPIGENETIC COMPONENT TO PROGRESSION OF CKD. UTILIZATION OF GENE-MAPPING STRATEGIES, RANGING FROM GENOME-WIDE ASSOCIATION STUDIES TO SINGLE-NUCLEOTIDE POLYMORPHISM ANALYSIS, SERVES TO IDENTIFY POTENTIAL GENETIC VARIANTS THAT MAY LEND TO DISEASE VARIATION. GENOME-WIDE ASSOCIATION STUDIES EVALUATING POPULATION-BASED DATA HAVE IDENTIFIED DIFFERENT LOCI ASSOCIATED WITH CKD PROGRESSION. ANALYSIS OF SINGLE-NUCLEOTIDE POLYMORPHISMS ON AN INDIVIDUAL LEVEL SUGGESTS THAT SECONDARY SYSTEMIC SEQUELAE OF CKD ARE CLOSELY RELATED TO DYSFUNCTION OF THE CARDIOVASCULAR-INFLAMMATORY AXIS AND MAY LEAD TO ADVANCED CARDIOVASCULAR DISEASE THROUGH ABNORMAL VASCULAR CALCIFICATION AND ACTIVATION OF THE RENIN-ANGIOTENSIN SYSTEM. SIMILARLY, GENETIC VARIANTS AFFECTING CYTOKINE CONTROL, FIBROSIS, AND PARENCHYMAL DEVELOPMENT MAY MODULATE CKD THROUGH DEVELOPMENT AND ACCELERATION OF RENAL INTERSTITIAL FIBROSIS. EPIGENETIC STUDIES EVALUATE MODIFICATION OF THE GENOME THROUGH DNA METHYLATION, HISTONE MODIFICATION, OR RNA INTERFERENCE, WHICH MAY BE DIRECTLY INFLUENCED BY EXTERNAL OR ENVIRONMENTAL FACTORS DIRECTING GENOMIC EXPRESSION. LASTLY, IMPROVED UNDERSTANDING OF THE GENETIC AND EPIGENETIC CONTRIBUTION TO CKD PROGRESSION MAY ALLOW PROVIDERS TO IDENTIFY A POPULATION AT ACCELERATED RISK FOR DISEASE PROGRESSION AND APPLY NOVEL THERAPIES TARGETED AT THE GENETIC MECHANISM OF DISEASE. 2016 13 1170 53 CONTRIBUTION OF GENETICS AND EPIGENETICS TO PROGRESSION OF KIDNEY FIBROSIS. CHRONIC KIDNEY DISEASE (CKD) WHICH CAN LEAD TO END-STAGE RENAL FAILURE REMAINS A PRINCIPAL CHALLENGE IN NEPHROLOGY. WHILE MECHANISTIC STUDIES PROVIDED EXTENSIVE INSIGHTS INTO THE COMMON PATHWAYS OF FIBROGENESIS WHICH UNDERLIE THE PROGRESSION OF CKD, THESE PRE-CLINICAL STUDIES FAIL TO FULLY EXPLAIN THE VASTLY DIFFERENT PROGRESSION SLOPES OF INDIVIDUAL PATIENTS. RECENT STUDIES PROVIDE EVIDENCE THAT GENETIC POLYMORPHISMS AND EPIGENETIC VARIATIONS DETERMINE THE INDIVIDUAL SUSCEPTIBILITY OF PATIENTS TO DEVELOP CHRONIC PROGRESSIVE KIDNEY DISEASE. HERE, WE REVIEW RECENT INSIGHTS THAT WERE PROVIDED BY GENOME-WIDE ASSOCIATION STUDIES (GWASS), GENE-LINKAGE STUDIES AND EPIGENOME ANALYSIS. THE PROGRESSION OF CKD TOWARDS END-STAGE RENAL FAILURE REMAINS A PRINCIPAL UNSOLVED PROBLEM IN NEPHROLOGY AS EFFECTIVE THERAPIES AND PREDICTIVE TESTS ARE STILL NOT AVAILABLE [ 1, 2]. CHRONIC PROGRESSIVE KIDNEY DISEASE IS CAUSED BY A WIDE RANGE OF DISEASES, WITH DIABETES MELLITUS, HYPERTENSION AND PRIMARY GLOMERULOPATHIES BEING THE MOST COMMON CAUSES IN THE WESTERN WORLD [ 3]. INFECTIONS, PHYSICAL OBSTRUCTION, INTERSTITIAL NEPHRITIDES AND GENETIC CYSTIC KIDNEY DISEASES ARE ALSO COMMON CAUSES OF END-STAGE RENAL DISEASE (ESRD) [ 3]. REGARDLESS OF THE PRIMARY UNDERLYING DISEASE, CHRONICALLY INJURED KIDNEYS ARE HISTOMORPHOLOGICALLY CHARACTERIZED BY TUBULOINTERSTITIAL FIBROSIS [ 1]. IN FACT, THE EXTENT OF TUBULOINTERSTITIAL FIBROSIS IS THE BEST PREDICTOR FOR KIDNEY SURVIVAL, IRRESPECTIVE OF THE UNDERLYING DISEASE. FOR THIS REASON, FIBROSIS IS CONSIDERED THE COMMON PATHWAY OF CHRONIC PROGRESSIVE KIDNEY DISEASE [ 1]. FIBROGENESIS IS A PATHOLOGICAL SCARRING PROCESS WHICH INVOLVES ACCUMULATION OF ACTIVATED FIBROBLASTS, EXCESSIVE DEPOSITION OF EXTRACELLULAR MATRIX, FAILED REGENERATION OF TUBULAR EPITHELIUM, MICROVASCULAR RAREFACTION AND (MOSTLY STERILE) INFLAMMATION [ 4]. FIBROGENESIS DEPENDS ON A COMPLEX INTERACTION OF THE INVOLVED CELL TYPES WHICH IS ORCHESTRATED BY AN EXTENSIVE NETWORK OF GROWTH FACTORS AND SIGNALLING PATHWAYS (WHICH ARE REVIEWED EXTENSIVELY ELSEWHERE) [ 1]. IN VIEW OF THE DETAILED MECHANISTIC KNOWLEDGE OF THE PATHWAYS THAT ORCHESTRATE RENAL FIBROGENESIS, IT IS PUZZLING WHY PROGRESSION RATES OF CKD DIFFER DRAMATICALLY AMONG PATIENTS WITH IDENTICAL UNDERLYING DISEASES [ 1, 2]. THE FIBROTIC PATHWAYS ARE KNOWN, BUT THE SWITCHES THAT CONTROL THEIR INTENSITIES AND WHICH DETERMINE THE SPEED AT WHICH FIBROSIS MOVES ALONG THE PROGRESSION SLOPE ARE NOT YET UNDERSTOOD [ 1, 2]. THE CONCEPT THAT GENETIC POLYMORPHISMS ARE THE BASIS FOR INDIVIDUAL PROGRESSION RATES OF CKD IS AN OBVIOUS AND ATTRACTIVE ONE. DISTINCT SUSCEPTIBILITIES OF DIFFERENT MOUSE AND RAT STRAINS TO EXPERIMENTAL CKD ARE A STRONG TESTAMENT OF THE IMPACT OF GENETIC VARIATIONS ON RENAL FIBROGENESIS. IDENTIFICATION OF THE UNDERLYING GENETIC POLYMORPHISMS AND MECHANISTIC PROOF OF THEIR INVOLVEMENT IN THE PROGRESSION OF CKD, HOWEVER, IS AN ONGOING CHALLENGE. THERE ARE TWO BASIC APPROACHES: ONE STRATEGY IS TO PERFORM UNBIASED SCREENING TO IDENTIFY GENES WHICH ARE ASSOCIATED WITH CHRONIC PROGRESSIVE KIDNEY DISEASE AND TO THEN PROVE THEIR MECHANISTIC RELEVANCE IN EXPERIMENTAL STUDIES ('GENOTYPE TO PHENOTYPE APPROACH'). THE SECOND STRATEGY IS TO SELECTIVELY ANALYSE POLYMORPHISMS OF GENES WHICH HAVE BEEN IDENTIFIED IN MECHANISTIC STUDIES AS DRIVERS OF RENAL FIBROGENESIS WITH REGARD TO THEIR ASSOCIATION WITH CKD (PHENOTYPE TO GENOTYPE APPROACH). THE PUZZLING OBSERVATION, HOWEVER, IS THAT GENETIC ANALYSIS AND MECHANISTIC STUDIES SO FAR RARELY COMPLEMENT EACH OTHER. THE CURRENT STATE OF AFFAIRS IS REVIEWED IN MORE DETAIL BELOW. 2014 14 5364 49 RECENT ADVANCES IN EPIGENETICS OF AGE-RELATED KIDNEY DISEASES. RENAL AGING HAS ATTRACTED INCREASING ATTENTION IN TODAY'S AGING SOCIETY, AS ELDERLY PEOPLE WITH ADVANCED AGE ARE MORE SUSCEPTIBLE TO VARIOUS KIDNEY DISORDERS SUCH AS ACUTE KIDNEY INJURY (AKI) AND CHRONIC KIDNEY DISEASE (CKD). THERE IS NO CLEAR-CUT UNIVERSAL MECHANISM FOR IDENTIFYING AGE-RELATED KIDNEY DISEASES, AND THEREFORE, THEY POSE A CONSIDERABLE MEDICAL AND PUBLIC HEALTH CHALLENGE. EPIGENETICS REFERS TO THE STUDY OF HERITABLE MODIFICATIONS IN THE REGULATION OF GENE EXPRESSION THAT DO NOT REQUIRE CHANGES IN THE UNDERLYING GENOMIC DNA SEQUENCE. A VARIETY OF EPIGENETIC MODIFIERS SUCH AS HISTONE DEACETYLASES (HDAC) INHIBITORS AND DNA METHYLTRANSFERASE (DNMT) INHIBITORS HAVE BEEN PROPOSED AS POTENTIAL BIOMARKERS AND THERAPEUTIC TARGETS IN NUMEROUS FIELDS INCLUDING CARDIOVASCULAR DISEASES, IMMUNE SYSTEM DISEASE, NERVOUS SYSTEM DISEASES, AND NEOPLASMS. ACCUMULATING EVIDENCE IN RECENT YEARS INDICATES THAT EPIGENETIC MODIFICATIONS HAVE BEEN IMPLICATED IN RENAL AGING. HOWEVER, NO PREVIOUS SYSTEMATIC REVIEW HAS BEEN PERFORMED TO SYSTEMATICALLY GENERALIZE THE RELATIONSHIP BETWEEN EPIGENETICS AND AGE-RELATED KIDNEY DISEASES. IN THIS REVIEW, WE AIM TO SUMMARIZE THE RECENT ADVANCES IN EPIGENETIC MECHANISMS OF AGE-RELATED KIDNEY DISEASES AS WELL AS DISCUSS THE APPLICATION OF EPIGENETIC MODIFIERS AS POTENTIAL BIOMARKERS AND THERAPEUTIC TARGETS IN THE FIELD OF AGE-RELATED KIDNEY DISEASES. IN SUMMARY, THE MAIN TYPES OF EPIGENETIC PROCESSES INCLUDING DNA METHYLATION, HISTONE MODIFICATIONS, NON-CODING RNA (NCRNA) MODULATION HAVE ALL BEEN IMPLICATED IN THE PROGRESSION OF AGE-RELATED KIDNEY DISEASES, AND THERAPEUTIC TARGETING OF THESE PROCESSES WILL YIELD NOVEL THERAPEUTIC STRATEGIES FOR THE PREVENTION AND/OR TREATMENT OF AGE-RELATED KIDNEY DISEASES. 2022 15 2542 41 EPIGENETICS IN KIDNEY DISEASES. EPIGENETICS EXAMINES HERITABLE CHANGES IN DNA AND ITS ASSOCIATED PROTEINS EXCEPT MUTATIONS IN GENE SEQUENCE. EPIGENETIC REGULATION PLAYS FUNDAMENTAL ROLES IN KIDNEY CELL BIOLOGY THROUGH THE ACTION OF DNA METHYLATION, CHROMATIN MODIFICATION VIA EPIGENETIC REGULATORS AND NON-CODING RNA SPECIES. KIDNEY DISEASES, INCLUDING ACUTE KIDNEY INJURY, CHRONIC KIDNEY DISEASE, DIABETIC KIDNEY DISEASE AND RENAL FIBROSIS ARE MULTISTEP PROCESSES ASSOCIATED WITH NUMEROUS MOLECULAR ALTERATIONS EVEN IN INDIVIDUAL KIDNEY CELLS. EPIGENETIC ALTERATIONS, INCLUDING ANOMALOUS DNA METHYLATION, ABERRANT HISTONE ALTERATIONS AND CHANGES OF MICRORNA EXPRESSION ALL CONTRIBUTE TO KIDNEY PATHOGENESIS. THESE CHANGES ALTER THE GENOME-WIDE EPIGENETIC SIGNATURES AND DISRUPT ESSENTIAL PATHWAYS THAT PROTECT RENAL CELLS FROM UNCONTROLLED GROWTH, APOPTOSIS AND DEVELOPMENT OF OTHER RENAL ASSOCIATED SYNDROMES. MOLECULAR CHANGES IMPACT CELLULAR FUNCTION WITHIN KIDNEY CELLS AND ITS MICROENVIRONMENT TO DRIVE AND MAINTAIN DISEASE PHENOTYPE. IN THIS CHAPTER, WE BRIEFLY SUMMARIZE EPIGENETIC MECHANISMS IN FOUR KIDNEY DISEASES INCLUDING ACUTE KIDNEY INJURY, CHRONIC KIDNEY DISEASE, DIABETIC KIDNEY DISEASE AND RENAL FIBROSIS. WE PRIMARILY FOCUS ON CURRENT KNOWLEDGE ABOUT THE GENOME-WIDE PROFILING OF DNA METHYLATION AND HISTONE MODIFICATION, AND EPIGENETIC REGULATION ON SPECIFIC GENE(S) IN THE PATHOPHYSIOLOGY OF THESE DISEASES AND THE TRANSLATIONAL POTENTIAL OF IDENTIFYING NEW BIOMARKERS AND TREATMENT FOR PREVENTION AND THERAPY. INCORPORATING EPIGENOMIC TESTING INTO CLINICAL RESEARCH IS ESSENTIAL TO ELUCIDATE NOVEL EPIGENETIC BIOMARKERS AND DEVELOP PRECISION MEDICINE USING EMERGING THERAPIES. 2021 16 4389 36 MODELING EPIGENETIC MODIFICATIONS IN RENAL DEVELOPMENT AND DISEASE WITH ORGANOIDS AND GENOME EDITING. UNDERSTANDING EPIGENETIC MECHANISMS IS CRUCIAL TO OUR COMPREHENSION OF GENE REGULATION IN DEVELOPMENT AND DISEASE. IN THE PAST DECADES, DIFFERENT STUDIES HAVE SHOWN THE ROLE OF EPIGENETIC MODIFICATIONS AND MODIFIERS IN RENAL DISEASE, ESPECIALLY DURING ITS PROGRESSION TOWARDS CHRONIC AND END-STAGE RENAL DISEASE. THUS, THE IDENTIFICATION OF GENETIC VARIATION ASSOCIATED WITH CHRONIC KIDNEY DISEASE HAS RESULTED IN BETTER CLINICAL MANAGEMENT OF PATIENTS. DESPITE THE IMPORTANCE OF THESE FINDINGS, THE TRANSLATION OF GENOTYPE-PHENOTYPE DATA INTO GENE-BASED MEDICINE IN CHRONIC KIDNEY DISEASE POPULATIONS STILL LACKS FAITHFUL CELLULAR OR ANIMAL MODELS THAT RECAPITULATE THE KEY ASPECTS OF THE HUMAN KIDNEY. THE LATEST ADVANCES IN THE FIELD OF STEM CELLS HAVE SHOWN THAT IT IS POSSIBLE TO EMULATE KIDNEY DEVELOPMENT AND FUNCTION WITH ORGANOIDS DERIVED FROM HUMAN PLURIPOTENT STEM CELLS. THESE HAVE SUCCESSFULLY RECAPITULATED NOT ONLY KIDNEY DIFFERENTIATION, BUT ALSO THE SPECIFIC PHENOTYPICAL TRAITS RELATED TO KIDNEY FUNCTION. THE COMBINATION OF THIS METHODOLOGY WITH CRISPR/CAS9 GENOME EDITING HAS ALREADY HELPED RESEARCHERS TO MODEL DIFFERENT GENETIC KIDNEY DISORDERS. NOWADAYS, CRISPR/CAS9-BASED APPROACHES ALSO ALLOW EPIGENETIC MODIFICATIONS, AND THUS REPRESENT AN UNPRECEDENTED TOOL FOR THE SCREENING OF GENETIC VARIANTS, EPIGENETIC MODIFICATIONS OR EVEN CHANGES IN CHROMATIN STRUCTURE THAT ARE ALTERED IN RENAL DISEASE. IN THIS REVIEW, WE DISCUSS THESE TECHNICAL ADVANCES IN KIDNEY MODELING, AND OFFER AN OVERVIEW OF THE ROLE OF EPIGENETIC REGULATION IN KIDNEY DEVELOPMENT AND DISEASE. 2018 17 1977 35 EPIGENETIC ALTERATIONS IN ACUTE KIDNEY INJURY. ACUTE KIDNEY INJURY (AKI) IS A RISK FACTOR FOR CHRONIC KIDNEY DISEASE AND DEATH. DESPITE PROGRESS MADE IN UNDERSTANDING THE CELLULAR AND MOLECULAR BASIS OF AKI PATHOGENESIS THERE HAS BEEN NO IMPROVEMENT IN THE HIGH MORTALITY RATE FROM THIS DISEASE IN DECADES. EPIGENETICS IS ONE OF THE MOST INTENSIVELY STUDIED FIELDS OF BIOLOGY TODAY AND REPRESENTS A NEW PARADIGM FOR UNDERSTANDING THE PATHOPHYSIOLOGY OF DISEASE. ALTHOUGH EPIGENETICS OF AKI IS A NASCENT FIELD, THE AVAILABLE INFORMATION ALREADY IS PROVIDING COMPELLING EVIDENCE THAT CHROMATIN BIOLOGY PLAYS A CRITICAL ROLE IN THIS DISEASE. IN THIS ARTICLE WE EXPLORE WHAT IS KNOWN ABOUT THE CONTRIBUTION OF EPIGENETIC MECHANISMS TO THE PATHOPHYSIOLOGY OF AKI AND HOW THIS KNOWLEDGE ALREADY IS GUIDING THE DEVELOPMENT OF NEW DIAGNOSTIC TOOLS AND EPIGENETIC THERAPIES. 2013 18 6446 51 THERAPEUTIC INSIGHTS IN CHRONIC KIDNEY DISEASE PROGRESSION. CHRONIC KIDNEY DISEASE (CKD) HAS BEEN RECOGNIZED AS A LEADING PUBLIC HEALTH PROBLEM WORLDWIDE. THROUGH ITS EFFECT ON CARDIOVASCULAR RISK AND END-STAGE KIDNEY DISEASE, CKD DIRECTLY AFFECTS THE GLOBAL BURDEN OF MORBIDITY AND MORTALITY. CLASSICAL OPTIMAL MANAGEMENT OF CKD INCLUDES BLOOD PRESSURE CONTROL, TREATMENT OF ALBUMINURIA WITH ANGIOTENSIN-CONVERTING ENZYME INHIBITORS OR ANGIOTENSIN II RECEPTOR BLOCKERS, AVOIDANCE OF POTENTIAL NEPHROTOXINS AND OBESITY, DRUG DOSING ADJUSTMENTS, AND CARDIOVASCULAR RISK REDUCTION. DIABETES MIGHT ACCOUNT FOR MORE THAN HALF OF CKD BURDEN, AND OBESITY IS THE MOST IMPORTANT PROMPTED FACTOR FOR THIS DISEASE. NEW ANTIHYPERGLYCEMIC DRUGS, SUCH AS SODIUM-GLUCOSE-COTRANSPORTER 2 INHIBITORS HAVE SHOWN TO SLOW THE DECLINE OF GFR, BRINGING ADDITIONAL BENEFIT IN WEIGHT REDUCTION, CARDIOVASCULAR, AND OTHER KIDNEY OUTCOMES. ON THE OTHER HAND, A NEW GENERATION OF NON-STEROIDAL MINERALOCORTICOID RECEPTOR ANTAGONIST HAS RECENTLY BEEN DEVELOPED TO OBTAIN A SELECTIVE RECEPTOR INHIBITION REDUCING SIDE EFFECTS LIKE HYPERKALEMIA AND THEREBY MAKING THE DRUGS SUITABLE FOR ADMINISTRATION TO CKD PATIENTS. MOREOVER, TWO NEW POTASSIUM-LOWERING THERAPIES HAVE SHOWN TO IMPROVE TOLERANCE, ALLOWING FOR HIGHER DOSAGE OF RENIN-ANGIOTENSIN SYSTEM INHIBITORS AND THEREFORE ENHANCING THEIR NEPHROPROTECTIVE EFFECT. REGARDLESS OF ITS CAUSE, CKD IS CHARACTERIZED BY REDUCED RENAL REGENERATION CAPACITY, MICROVASCULAR DAMAGE, OXIDATIVE STRESS AND INFLAMMATION, RESULTING IN FIBROSIS AND PROGRESSIVE, AND IRREVERSIBLE NEPHRON LOSS. THEREFORE, A HOLISTIC APPROACH SHOULD BE TAKEN TARGETING THE DIVERSE PROCESSES AND BIOLOGICAL CONTEXTS THAT ARE ASSOCIATED WITH CKD PROGRESSION. TO DATE, THERAPEUTIC INTERVENTIONS WHEN TUBULOINTERSTITIAL FIBROSIS IS ALREADY ESTABLISHED HAVE PROVED TO BE INSUFFICIENT, THUS RESEARCH EFFORT SHOULD FOCUS ON UNRAVELING EARLY DISEASE MECHANISMS. AN ARRAY OF NOVEL THERAPEUTIC APPROACHES TARGETING EPIGENETIC REGULATORS ARE NOW UNDERGOING PHASE II OR PHASE III TRIALS AND MIGHT PROVIDE A SIMULTANEOUS REGULATORY ACTIVITY THAT COORDINATELY REGULATE DIFFERENT ASPECTS OF CKD PROGRESSION. 2021 19 2193 52 EPIGENETIC MODIFICATION DRIVES ACUTE KIDNEY INJURY-TO-CHRONIC KIDNEY DISEASE PROGRESSION. ACUTE KIDNEY INJURY (AKI) IS A COMMON CLINICAL CRITICAL DISEASE. DUE TO ITS HIGH MORBIDITY, INCREASING RISK OF COMPLICATIONS, HIGH MORTALITY RATE, AND HIGH MEDICAL COSTS, IT HAS BECOME A GLOBAL CONCERN FOR HUMAN HEALTH PROBLEMS. INITIALLY, RESEARCHERS BELIEVED THAT KIDNEYS HAVE A STRONG ABILITY TO REGENERATE AND REPAIR, BUT STUDIES OVER THE PAST 20 YEARS HAVE FOUND THAT KIDNEYS DAMAGED BY AKI ARE OFTEN INCOMPLETE OR EVEN UNABLE TO REPAIR. EVEN WHEN SERUM CREATININE RETURNS TO BASELINE LEVELS, RENAL STRUCTURAL DAMAGE PERSISTS FOR A LONG TIME, LEADING TO THE DEVELOPMENT OF CHRONIC KIDNEY DISEASE (CKD). THE MECHANISM OF AKI-TO-CKD TRANSITION HAS NOT BEEN FULLY ELUCIDATED. AS AN IMPORTANT REGULATOR OF GENE EXPRESSION, EPIGENETIC MODIFICATIONS, SUCH AS HISTONE MODIFICATION, DNA METHYLATION, AND NONCODING RNAS, MAY PLAY AN IMPORTANT ROLE IN THIS PROCESS. ALTERATIONS IN EPIGENETIC MODIFICATION ARE INDUCED BY HYPOXIA, THUS PROMOTING THE EXPRESSION OF INFLAMMATORY FACTOR-RELATED GENES AND COLLAGEN SECRETION. THIS REVIEW ELABORATED THE ROLE OF EPIGENETIC MODIFICATIONS IN AKI-TO-CKD PROGRESSION, THE DIAGNOSTIC VALUE OF EPIGENETIC MODIFICATIONS BIOMARKERS IN AKI CHRONIC OUTCOME, AND THE POTENTIAL ROLE OF TARGETING EPIGENETIC MODIFICATIONS IN THE PREVENTION AND TREATMENT OF AKI TO CKD, IN ORDER TO PROVIDE IDEAS FOR THE SUBSEQUENT ESTABLISHMENT OF TARGETED THERAPEUTIC STRATEGIES TO PREVENT THE PROGRESSION OF RENAL TUBULAR-INTERSTITIAL FIBROSIS. 2021 20 5370 27 RECENT ADVANCES IN UNDERSTANDING OF CHRONIC KIDNEY DISEASE. CHRONIC KIDNEY DISEASE (CKD) IS DEFINED AS ANY CONDITION THAT CAUSES REDUCED KIDNEY FUNCTION OVER A PERIOD OF TIME. FIBROSIS, TUBULAR ATROPHY AND INTERSTITIAL INFLAMMATION ARE THE HALLMARK OF PATHOLOGICAL FEATURES IN CKD. REGARDLESS OF INITIAL INSULT, CKD HAS SOME COMMON PATHWAYS LEADING CKD TO END-STAGE KIDNEY DISEASE, INCLUDING HYPOXIA IN THE TUBULOINTERSTITIUM AND PROTEINURIA. RECENT ADVANCES IN GENOME EDITING TECHNOLOGIES AND STEM CELL RESEARCH GIVE GREAT INSIGHTS TO UNDERSTAND THE PATHOGENESIS OF CKD, INCLUDING IDENTIFICATIONS OF THE ORIGINS OF RENAL MYOFIBROBLASTS AND TUBULAR EPITHELIAL CELLS UPON INJURY. ENVIRONMENTAL FACTORS SUCH AS HYPOXIA, OXIDATIVE STRESS, AND EPIGENETIC FACTORS IN RELATION TO CKD ARE ALSO DISCUSSED. 2015