1 3635 122 INCREASED DNA METHYLATION, CELLULAR SENESCENCE AND PREMATURE EPIGENETIC AGING IN GUINEA PIGS AND HUMANS WITH TUBERCULOSIS. BACKGROUND: TUBERCULOSIS (TB) IS THE ARCHETYPICAL CHRONIC INFECTION, WITH PATIENTS HAVING MONTHS OF SYMPTOMS BEFORE DIAGNOSIS. IN THE TWO YEARS AFTER SUCCESSFUL THERAPY, SURVIVORS OF TB HAVE A THREE-FOLD INCREASED RISK OF DEATH. METHODS: GUINEA PIGS WERE INFECTED WITH MYCOBACTERIUM TUBERCULOSIS (MTB) FOR 45 DAYS, FOLLOWED BY RRBS DNA METHYLATION ANALYSIS. IN HUMANS, NETWORK ANALYSIS OF DIFFERENTIALLY EXPRESSED GENES ACROSS THREE TB COHORTS WERE VISUALIZED AT THE PATHWAY-LEVEL. SERUM LEVELS OF INFLAMMATION WERE MEASURED BY ELISA. HORVATH (DNA METHYLATION) AND RNA-SEQ BIOLOGICAL CLOCKS WERE USED TO INVESTIGATE SHIFTS IN CHRONOLOGICAL AGE AMONG HUMANS WITH TB. RESULTS: GUINEA PIGS WITH TB DEMONSTRATED DNA HYPERMETHYLATION AND SHOWED SYSTEM-LEVEL SIMILARITY TO HUMANS WITH TB (P-VALUE = 0.002). THE TRANSCRIPTOME IN TB IN MULTIPLE COHORTS WAS ENRICHED FOR DNA METHYLATION AND CELLULAR SENESCENCE. SENESCENCE ASSOCIATED PROTEINS CXCL9, CXCL10, AND TNF WERE ELEVATED IN TB PATIENTS COMPARED TO HEALTHY CONTROLS. HUMANS WITH TB DEMONSTRATE 12.7 YEARS (95% CI: 7.5, 21.9) AND 14.38 YEARS (95% CI: 10.23-18.53) OF CELLULAR AGING AS MEASURED BY EPIGENETIC AND GENE EXPRESSION BASED CELLULAR CLOCKS, RESPECTIVELY. CONCLUSIONS: IN BOTH GUINEA PIGS AND HUMANS, TB PERTURBS EPIGENETIC PROCESSES, PROMOTING PREMATURE CELLULAR AGING AND INFLAMMATION, A PLAUSIBLE MEANS TO EXPLAIN THE LONG-TERM DETRIMENTAL HEALTH OUTCOMES AFTER TB. 2022 2 6311 27 THE RELATION BETWEEN DNA METHYLATION PATTERNS AND SERUM CYTOKINE LEVELS IN COMMUNITY-DWELLING ADULTS: A PRELIMINARY STUDY. BACKGROUND: THE LEVELS OF CIRCULATING CYTOKINES FLUCTUATE WITH AGE, ACUTE ILLNESS, AND CHRONIC DISEASE, AND ARE PREDICTIVE OF MORTALITY; THIS IS ALSO TRUE FOR PATTERNS OF DNA (CPG) METHYLATION. GIVEN THAT IMMUNE CELLS ARE PARTICULARLY SENSITIVE TO CHANGES IN THE CONCENTRATION OF CYTOKINES IN THEIR MICROENVIRONMENT, WE HYPOTHESIZED THAT SERUM LEVELS OF TNF, IL-6, IL-8 AND IL-10 WOULD CORRELATE WITH GENOME-WIDE ALTERATIONS IN THE DNA METHYLATION LEVELS OF BLOOD LEUKOCYTES. TO TEST THIS, WE EVALUATED COMMUNITY-DWELLING ADULTS (N = 14; 48-78 YEARS OLD) RECRUITED TO A PILOT STUDY FOR THE CANADIAN LONGITUDINAL STUDY ON AGING (CLSA), EXAMINING DNA METHYLATION PATTERNS IN PERIPHERAL BLOOD MONONUCLEAR CELLS USING THE ILLUMINA HUMANMETHYLATION 450 K BEADCHIP. RESULTS: WE SHOW THAT, APART FROM AGE, SERUM IL-10 LEVELS EXHIBITED THE MOST SUBSTANTIAL ASSOCIATION TO DNA METHYLATION PATTERNS, FOLLOWED BY TNF, IL-6 AND IL-8. FURTHERMORE, WHILE THE LEVELS OF THESE CYTOKINES WERE HIGHER IN ELDERLY ADULTS, NO ASSOCIATIONS WITH EPIGENETIC ACCELERATED AGING, DERIVED USING THE EPIGENETIC CLOCK, WERE OBSERVED. CONCLUSIONS: AS A PRELIMINARY STUDY WITH A SMALL SAMPLE SIZE, THE CONCLUSIONS DRAWN FROM THIS WORK MUST BE VIEWED WITH CAUTION; HOWEVER, OUR OBSERVATIONS ARE ENCOURAGING AND CERTAINLY WARRANT MORE SUITABLY POWERED STUDIES OF THIS RELATIONSHIP. 2017 3 1723 29 DYSREGULATION OF C-X-C MOTIF LIGAND 10 DURING AGING AND ASSOCIATION WITH COGNITIVE PERFORMANCE. CHRONIC LOW-GRADE INFLAMMATION DURING AGING (INFLAMMAGING) IS ASSOCIATED WITH COGNITIVE DECLINE AND NEURODEGENERATION; HOWEVER, THE MECHANISMS UNDERLYING INFLAMMAGING ARE UNCLEAR. WE STUDIED A POPULATION (N = 361) OF HEALTHY YOUNG AND OLD ADULTS FROM THE MYOAGE COHORT. PERIPHERAL LEVELS OF C-X-C MOTIF CHEMOKINE LIGAND 10 (CXCL10) WAS FOUND TO BE HIGHER IN OLDER ADULTS, COMPARED WITH YOUNG, AND NEGATIVELY ASSOCIATED WITH WORKING MEMORY PERFORMANCE. THIS COINCIDED WITH AN AGE-RELATED REDUCTION IN BLOOD DNA METHYLATION AT SPECIFIC CPGS WITHIN THE CXCL10 GENE PROMOTER. IN VITRO ANALYSIS SUPPORTED THE ROLE OF DNA METHYLATION IN REGULATING CXCL10 TRANSCRIPTION. A POLYMORPHISM (RS56061981) THAT ALTERED METHYLATION AT ONE OF THESE CPG SITES FURTHER ASSOCIATED WITH WORKING MEMORY PERFORMANCE IN 2 INDEPENDENT AGING COHORTS. STUDYING PREFRONTAL CORTEX SAMPLES, WE FOUND HIGHER CXCL10 PROTEIN LEVELS IN THOSE WITH ALZHEIMER'S DISEASE, COMPARED WITH AGED CONTROLS. THESE FINDINGS SUPPORT THE ASSOCIATION OF PERIPHERAL INFLAMMATION, AS DEMONSTRATED BY CXCL10, IN AGING AND COGNITIVE DECLINE. WE REVEAL AGE-RELATED EPIGENETIC AND GENETIC FACTORS WHICH CONTRIBUTE TO THE DYSREGULATION OF CXCL10. 2018 4 2079 33 EPIGENETIC DNA METHYLATION CHANGES ASSOCIATED WITH HEADACHE CHRONIFICATION: A RETROSPECTIVE CASE-CONTROL STUDY. BACKGROUND THE BIOLOGICAL MECHANISMS OF HEADACHE CHRONIFICATION ARE POORLY UNDERSTOOD. WE AIMED TO IDENTIFY CHANGES IN DNA METHYLATION ASSOCIATED WITH THE TRANSFORMATION FROM EPISODIC TO CHRONIC HEADACHE. METHODS PARTICIPANTS WERE RECRUITED FROM THE POPULATION-BASED NORWEGIAN HUNT STUDY. THIRTY-SIX FEMALE HEADACHE PATIENTS WHO TRANSFORMED FROM EPISODIC TO CHRONIC HEADACHE BETWEEN BASELINE AND FOLLOW-UP 11 YEARS LATER WERE MATCHED AGAINST 35 CONTROLS WITH EPISODIC HEADACHE. DNA METHYLATION WAS QUANTIFIED AT 485,000 CPG SITES, AND CHANGES IN METHYLATION LEVEL AT THESE SITES WERE COMPARED BETWEEN CASES AND CONTROLS BY LINEAR REGRESSION ANALYSIS. DATA WERE ANALYZED IN TWO STAGES (STAGES 1 AND 2) AND IN A COMBINED META-ANALYSIS. RESULTS NONE OF THE TOP 20 CPG SITES IDENTIFIED IN STAGE 1 REPLICATED IN STAGE 2 AFTER MULTIPLE TESTING CORRECTION. IN THE COMBINED META-ANALYSIS THE STRONGEST ASSOCIATED CPG SITES WERE RELATED TO SH2D5 AND NPTX2, TWO BRAIN-EXPRESSED GENES INVOLVED IN THE REGULATION OF SYNAPTIC PLASTICITY. FUNCTIONAL ENRICHMENT ANALYSIS POINTED TO PROCESSES INCLUDING CALCIUM ION BINDING AND ESTROGEN RECEPTOR PATHWAYS. CONCLUSION IN THIS FIRST GENOME-WIDE STUDY OF DNA METHYLATION IN HEADACHE CHRONIFICATION SEVERAL POTENTIALLY IMPLICATED LOCI AND PROCESSES WERE IDENTIFIED. THE STUDY EXEMPLIFIES THE USE OF PROSPECTIVELY COLLECTED POPULATION COHORTS TO SEARCH FOR EPIGENETIC MECHANISMS OF DISEASE. 2018 5 2400 30 EPIGENETIC REPROGRAMMING OF IMMUNE CELLS IN WOMEN WITH PCOS IMPACT GENES CONTROLLING REPRODUCTIVE FUNCTION. CONTEXT: POLYCYSTIC OVARY SYNDROME (PCOS) IS A CHRONIC DISEASE AFFECTING REPRODUCTIVE FUNCTION AND WHOLE-BODY METABOLISM. ALTHOUGH THE ETIOLOGY IS UNCLEAR, EMERGING EVIDENCE INDICATES THAT THE EPIGENETICS MAY BE A CONTRIBUTING FACTOR. OBJECTIVE: TO DETERMINE THE ROLE OF GLOBAL AND GENOME-WIDE EPIGENETIC MODIFICATIONS IN SPECIFIC IMMUNE CELLS IN PCOS COMPARED WITH CONTROLS AND WHETHER THESE COULD BE RELATED TO CLINICAL FEATURES OF PCOS. DESIGN: CROSS-SECTIONAL STUDY. PARTICIPANTS: WOMEN WITH (N = 17) OR WITHOUT PCOS (N = 17). SETTING: RECRUITED FROM THE GENERAL COMMUNITY. MAIN OUTCOME MEASURES: ISOLATED PERIPHERAL BLOOD MONONUCLEAR CELLS WERE ANALYZED USING MULTICOLOR FLOW CYTOMETRY METHODS TO DETERMINE GLOBAL DNA METHYLATION LEVELS IN A CELL-SPECIFIC FASHION. TRANSCRIPTOMIC AND GENOME-WIDE DNA METHYLATION ANALYSES WERE PERFORMED ON T HELPER CELLS USING RNA SEQUENCING AND REDUCED REPRESENTATION BISULFITE SEQUENCING. RESULTS: WOMEN WITH PCOS HAD LOWER GLOBAL DNA METHYLATION IN MONOCYTES (P = 0.006) AND IN T HELPER (P = 0.004), T CYTOTOXIC (P = 0.004), AND B CELLS (P = 0.03). SPECIFIC GENOME-WIDE DNA METHYLATION ANALYSIS OF T HELPER CELLS FROM WOMEN WITH PCOS IDENTIFIED 5581 DIFFERENTIALLY METHYLATED CPG SITES. FUNCTIONAL GENE ONTOLOGY ENRICHMENT ANALYSIS SHOWED THAT GENES LOCATED AT THE PROXIMITY OF DIFFERENTIALLY METHYLATED CPG SITES BELONG TO PATHWAYS RELATED TO REPRODUCTIVE FUNCTION AND IMMUNE CELL FUNCTION. HOWEVER, THESE GENES WERE NOT ALTERED AT THE TRANSCRIPTOMIC LEVEL. CONCLUSIONS: IT WAS SHOWN THAT PCOS IS ASSOCIATED WITH GLOBAL AND GENE-SPECIFIC DNA METHYLATION REMODELING IN A CELL TYPE-SPECIFIC MANNER. FURTHER INVESTIGATION IS WARRANTED TO DETERMINE WHETHER EPIGENETIC REPROGRAMMING OF IMMUNE CELLS IS IMPORTANT IN DETERMINING THE DIFFERENT PHENOTYPES OF PCOS. 2019 6 2418 32 EPIGENETIC SIGNATURE OF CHRONIC LOW BACK PAIN IN HUMAN T CELLS. OBJECTIVE: DETERMINE IF CHRONIC LOW BACK PAIN (LBP) IS ASSOCIATED WITH DNA METHYLATION SIGNATURES IN HUMAN T CELLS THAT WILL REVEAL NOVEL MECHANISMS AND POTENTIAL THERAPEUTIC TARGETS AND EXPLORE THE FEASIBILITY OF EPIGENETIC DIAGNOSTIC MARKERS FOR PAIN-RELATED PATHOPHYSIOLOGY. METHODS: GENOME-WIDE DNA METHYLATION ANALYSIS OF 850,000 CPG SITES IN WOMEN AND MEN WITH CHRONIC LBP AND PAIN-FREE CONTROLS WAS PERFORMED. T CELLS WERE ISOLATED (DISCOVERY COHORT, N = 32) AND USED TO IDENTIFY DIFFERENTIALLY METHYLATED CPG SITES, AND GENE ONTOLOGIES AND MOLECULAR PATHWAYS WERE IDENTIFIED. A POLYGENIC DNA METHYLATION SCORE FOR LBP WAS GENERATED IN BOTH WOMEN AND MEN. VALIDATION WAS PERFORMED IN AN INDEPENDENT COHORT (VALIDATION COHORT, N = 63) OF CHRONIC LBP AND HEALTHY CONTROLS. RESULTS: ANALYSIS WITH THE DISCOVERY COHORT REVEALED A TOTAL OF 2,496 AND 419 DIFFERENTIALLY METHYLATED CPGS IN WOMEN AND MEN, RESPECTIVELY. IN WOMEN, MOST OF THESE SITES WERE HYPOMETHYLATED AND ENRICHED IN GENES WITH FUNCTIONS IN THE EXTRACELLULAR MATRIX, IN THE IMMUNE SYSTEM (IE, CYTOKINES), OR IN EPIGENETIC PROCESSES. IN MEN, A UNIQUE CHRONIC LBP DNA METHYLATION SIGNATURE WAS IDENTIFIED CHARACTERIZED BY SIGNIFICANT ENRICHMENT FOR GENES FROM THE MAJOR HISTOCOMPATIBILITY COMPLEX. SEX-SPECIFIC POLYGENIC DNA METHYLATION SCORES WERE GENERATED TO ESTIMATE THE PAIN STATUS OF EACH INDIVIDUAL AND CONFIRMED IN THE VALIDATION COHORT USING PYROSEQUENCING. CONCLUSION: THIS STUDY REVEALS SEX-SPECIFIC DNA METHYLATION SIGNATURES IN HUMAN T CELLS THAT DISCRIMINATES CHRONIC LBP PARTICIPANTS FROM HEALTHY CONTROLS. 2021 7 3 36 "EPIGENOME-WIDE METHYLATION PROFILE OF CHRONIC KIDNEY DISEASE-DERIVED ARTERIAL DNA UNCOVERS NOVEL PATHWAYS IN DISEASE-ASSOCIATED CARDIOVASCULAR PATHOLOGY.". CHRONIC KIDNEY DISEASE (CKD) RELATED CARDIOVASCULAR DISEASE (CVD) IS CHARACTERIZED BY VASCULAR REMODELLING WITH WELL-ESTABLISHED STRUCTURAL AND FUNCTIONAL CHANGES IN THE VASCULAR WALL SUCH AS ARTERIAL STIFFNESS, MATRIX DEPOSITION, AND CALCIFICATION. THESE PHENOTYPIC CHANGES RESEMBLE PATHOLOGY SEEN IN AGEING, AND ARE LIKELY TO BE MEDIATED BY SUSTAINED ALTERATIONS IN GENE EXPRESSION, WHICH MAY BE CAUSED BY EPIGENETIC CHANGES SUCH AS TISSUE-SPECIFIC DNA METHYLATION. WE AIMED TO INVESTIGATE TISSUE SPECIFIC CHANGES IN DNA METHYLATION THAT OCCUR IN CKD-RELATED CVD. GENOME-WIDE DNA METHYLATION CHANGES WERE EXAMINED IN BISULPHITE CONVERTED GENOMIC DNA ISOLATED FROM THE VASCULAR MEDIA OF CKD AND HEALTHY ARTERIES. METHYLATION-SPECIFIC PCR WAS USED TO VALIDATE THE ARRAY DATA, AND THE ASSOCIATION BETWEEN DNA METHYLATION AND GENE AND PROTEIN EXPRESSION WAS EXAMINED. THE DNA METHYLATION AGE WAS COMPARED TO THE CHRONOLOGICAL AGE IN BOTH CASES AND CONTROLS. THREE HUNDRED AND NINETEEN DIFFERENTIALLY METHYLATED REGIONS (DMR) WERE IDENTIFIED SPREAD ACROSS THE GENOME. PATHWAY ANALYSIS REVEALED THAT DMRS ASSOCIATED WITH GENES WERE INVOLVED IN EMBRYONIC AND VASCULAR DEVELOPMENT, AND SIGNALLING PATHWAYS SUCH AS TGFBETA AND FGF. EXPRESSION OF TOP DIFFERENTIALLY METHYLATED GENE HOXA5 SHOWED A SIGNIFICANT NEGATIVE CORRELATION WITH DNA METHYLATION. INTERESTINGLY, DNA METHYLATION AGE AND CHRONOLOGICAL AGE WERE HIGHLY CORRELATED, BUT THERE WAS NO EVIDENCE OF ACCELERATED AGE-RELATED DNA METHYLATION IN THE ARTERIES OF CKD PATIENTS. IN CONCLUSION, WE DEMONSTRATED THAT DIFFERENTIAL DNA METHYLATION IN THE ARTERIAL TISSUE OF CKD PATIENTS REPRESENTS A POTENTIAL MEDIATOR OF ARTERIAL PATHOLOGY AND MAY BE USED TO UNCOVER NOVEL PATHWAYS IN THE GENESIS OF CKD-ASSOCIATED COMPLICATIONS. 2021 8 1497 29 DNA METHYLATION AGE IS ACCELERATED IN ALCOHOL DEPENDENCE. ALCOHOL DEPENDENCE (ALC) IS A CHRONIC, RELAPSING DISORDER THAT INCREASES THE BURDEN OF CHRONIC DISEASE AND SIGNIFICANTLY CONTRIBUTES TO NUMEROUS PREMATURE DEATHS EACH YEAR. PREVIOUS RESEARCH SUGGESTS THAT CHRONIC, HEAVY ALCOHOL CONSUMPTION IS ASSOCIATED WITH DIFFERENTIAL DNA METHYLATION PATTERNS. IN ADDITION, DNA METHYLATION LEVELS AT CERTAIN CPG SITES HAVE BEEN CORRELATED WITH AGE. WE USED AN EPIGENETIC CLOCK TO INVESTIGATE THE POTENTIAL ROLE OF EXCESSIVE ALCOHOL CONSUMPTION IN EPIGENETIC AGING. WE EXPLORED THIS QUESTION IN FIVE INDEPENDENT COHORTS, INCLUDING DNA METHYLATION DATA DERIVED FROM DATASETS FROM BLOOD (N = 129, N = 329), LIVER (N = 92, N = 49), AND POSTMORTEM PREFRONTAL CORTEX (N = 46). ONE BLOOD DATASET AND ONE LIVER TISSUE DATASET OF INDIVIDUALS WITH ALC EXHIBITED POSITIVE AGE ACCELERATION (P < 0.0001 AND P = 0.0069, RESPECTIVELY), WHEREAS THE OTHER BLOOD AND LIVER TISSUE DATASETS BOTH EXHIBITED TRENDS OF POSITIVE AGE ACCELERATION THAT WERE NOT SIGNIFICANT (P = 0.83 AND P = 0.57, RESPECTIVELY). PREFRONTAL CORTEX TISSUE EXHIBITED A TREND OF NEGATIVE AGE ACCELERATION (P = 0.19). THESE RESULTS SUGGEST THAT EXCESSIVE ALCOHOL CONSUMPTION MAY BE ASSOCIATED WITH EPIGENETIC AGING IN A TISSUE-SPECIFIC MANNER AND WARRANTS FURTHER INVESTIGATION USING MULTIPLE TISSUE SAMPLES FROM THE SAME INDIVIDUALS. 2018 9 3387 22 HOMOCYSTEINE ASSOCIATED GENOMIC DNA HYPERMETHYLATION IN PATIENTS WITH CHRONIC ALCOHOLISM. HIGHER PLASMA HOMOCYSTEINE CONCENTRATIONS CAN INFLUENCE GENOMIC DNA METHYLATION IN PERIPHERAL BLOOD CELLS. IN THE PRESENT CONTROLLED STUDY WE OBSERVED A SIGNIFICANT INCREASE (10%) OF GENOMIC DNA METHYLATION IN PATIENTS WITH ALCOHOLISM (T = -3.16, DF = 158, P = 0.002) WHICH WAS SIGNIFICANTLY ASSOCIATED WITH THEIR ELEVATED HOMOCYSTEINE LEVELS (MULTIPLE LINEAR REGRESSION, P < 0.001). SINCE METHYLATION OF DNA IS AN IMPORTANT EPIGENETIC FACTOR IN REGULATION OF GENE EXPRESSION THESE FINDINGS MAY HAVE IMPORTANT IMPLICATIONS FOR A POSSIBLE SUBSEQUENT DERANGEMENT OF EPIGENETIC CONTROL THESE PATIENTS. 2004 10 2766 30 EXPRESSION, POLYMORPHISM AND METHYLATION PATTERN OF INTERLEUKIN-6 IN PERIODONTAL TISSUES. PERIODONTITIS IS CONSIDERED AN INFLAMMATORY DISORDER OF BACTERIAL ETIOLOGY THAT RESULTS IN PERIODONTAL TISSUE DESTRUCTION, AS A RESULT OF COMPLEX INTERACTIONS BETWEEN PERIODONTAL PATHOGENS, HOST AND IMMUNE RESPONSE. GENETIC AND EPIGENETIC MECHANISMS MAY MODULATE THE INDIVIDUAL RESPONSE SINCE IT IS ABLE TO INFLUENCE THE GENE EXPRESSION. THE AIM OF THIS STUDY WAS TO EVALUATE THE IMPACT OF -174 G/C POLYMORPHISM AND THE METHYLATION STATUS OF THE PROMOTER REGION OF IL-6 GENE ON THE EXPRESSION OF IL-6 IN GINGIVAL SAMPLES FROM INDIVIDUALS WITH CHRONIC PERIODONTITIS. GINGIVAL BIOPSIES WERE COLLECTED FROM 21 PATIENTS WITH CHRONIC PERIODONTITIS AND 21 CONTROLS. HISTOLOGIC SECTIONS STAINED BY HEMATOXYLIN-EOSIN WERE USED FOR HISTOPATHOLOGICAL EVALUATION. THE IL-6 GENE EXPRESSION WAS ASSESSED BY QUANTITATIVE REAL-TIME PCR. THE POLYMORPHISM IL-6 -174 C/G WAS STUDIED BY POLYMERASE CHAIN REACTION (PCR) AMPLIFICATION AND RESTRICTION ENDONUCLEASE DIGESTION (HSPII). METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION WAS USED TO VERIFY THE DNA METHYLATION PATTERN. THE NUMBER OF INFLAMMATORY CELLS IN TISSUE FRAGMENTS FROM INDIVIDUALS WITH CHRONIC PERIODONTITIS WAS HIGHER THAN IN THE CONTROL GROUP AND THE INFLAMMATORY INFILTRATE WAS PREDOMINANTLY MONONUCLEAR. THE EXPRESSION OF IL-6 WAS HIGHER IN THE GROUP WITH PERIODONTITIS. IN POLYMORPHISM ASSAY, NO STATISTICAL DIFFERENCE IN THE DISTRIBUTION OF GENOTYPES AND ALLELES IN BOTH GROUPS WERE OBSERVED. THE MOST OF SAMPLES WERE PARTIALLY METHYLATED. NO DIFFERENCE WAS OBSERVED IN METHYLATION PATTERN FROM TWO DIFFERENT REGIONS OF THE IL-6 GENE AMONG GROUPS. THE HIGH EXPRESSION OF IL-6 IS AN IMPORTANT FACTOR RELATED TO CHRONIC PERIODONTITIS, BUT WAS NOT ASSOCIATED WITH METHYLATION STATUS OR THE -174 (G/C) GENETIC POLYMORPHISM, SUGGESTING THAT OTHER MECHANISMS ARE INVOLVED IN THIS GENE TRANSCRIPTION REGULATION. 2013 11 2633 35 EPIGENOME-WIDE DNA METHYLATION PATTERNS ASSOCIATED WITH FATIGUE IN PRIMARY SJOGREN'S SYNDROME. OBJECTIVE: CHRONIC FATIGUE IS A COMMON, DISABLING AND POORLY UNDERSTOOD PHENOMENON. RECENT STUDIES INDICATE THAT EPIGENETIC MECHANISMS MAY BE INVOLVED IN THE EXPRESSION OF FATIGUE, A PROMINENT FEATURE OF PRIMARY SS (PSS). THE AIM OF THIS STUDY WAS TO INVESTIGATE WHETHER DNA METHYLATION PROFILES OF WHOLE BLOOD ARE ASSOCIATED WITH FATIGUE IN PATIENTS WITH PSS. METHODS: FORTY-EIGHT PSS PATIENTS WITH HIGH (N = 24) OR LOW (N = 24) FATIGUE AS MEASURED BY A VISUAL ANALOGUE SCALE WERE INCLUDED. GENOME-WIDE DNA METHYLATION WAS INVESTIGATED USING THE ILLUMINA HUMANMETHYLATION450 BEADCHIP ARRAY. AFTER QUALITY CONTROL, A TOTAL OF 383 358 CYTOSINE-PHOSPHATE-GUANINE (CPG) SITES REMAINED FOR FURTHER ANALYSIS. AGE, SEX AND DIFFERENTIAL CELL COUNT ESTIMATES WERE INCLUDED AS COVARIATES IN THE ASSOCIATION MODEL. A FALSE DISCOVERY RATE-CORRECTED P < 0.05 WAS CONSIDERED SIGNIFICANT, AND A CUT-OFF OF 3% AVERAGE DIFFERENCE IN METHYLATION LEVELS BETWEEN HIGH- AND LOW-FATIGUE PATIENTS WAS APPLIED. RESULTS: A TOTAL OF 251 DIFFERENTIALLY METHYLATED CPG SITES WERE ASSOCIATED WITH FATIGUE. THE CPG SITE WITH THE MOST PRONOUNCED HYPOMETHYLATION IN PSS HIGH FATIGUE ANNOTATED TO THE SBF2-ANTISENSE RNA1 GENE. THE MOST DISTINCT HYPERMETHYLATION WAS OBSERVED AT A CPG SITE ANNOTATED TO THE LYMPHOTOXIN ALPHA GENE. FUNCTIONAL PATHWAY ANALYSIS OF GENES WITH DIFFERENTLY METHYLATED CPG SITES IN SUBJECTS WITH HIGH VS LOW FATIGUE REVEALED ENRICHMENT IN SEVERAL PATHWAYS ASSOCIATED WITH INNATE AND ADAPTIVE IMMUNITY. CONCLUSION: SOME GENES INVOLVED IN REGULATION OF THE IMMUNE SYSTEM AND IN INFLAMMATION ARE DIFFERENTLY METHYLATED IN PSS PATIENTS WITH HIGH VS LOW FATIGUE. THESE FINDINGS POINT TO FUNCTIONAL NETWORKS THAT MAY UNDERLIE FATIGUE. EPIGENETIC CHANGES COULD CONSTITUTE A FATIGUE-REGULATING MECHANISM IN PSS. 2016 12 1589 35 DNA METHYLATION PROFILING IN A CIGARETTE SMOKE-EXPOSED MOUSE MODEL OF AIRWAY INFLAMMATION. PURPOSE: DNA METHYLATION, A MAJOR EPIGENETIC MODIFICATION, HAS BEEN DOCUMENTED TO PLAY AN IMPORTANT ROLE IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD). IN THIS STUDY, WE AIMED TO PROFILE THE DNA METHYLATION PATTERNS IN A MOUSE MODEL OF AIRWAY INFLAMMATION INDUCED BY CIGARETTE SMOKE (CS), A FOREMOST RISK FACTOR OF COPD. MATERIAL AND METHODS: TO ESTABLISH A MODEL OF AIRWAY INFLAMMATION, WILD-TYPE MICE WERE EXPOSED TO MAINSTREAM CS OR ROOM AIR FOR 2 HOURS TWICE DAILY, 6 DAYS PER WEEK FOR CONSECUTIVE 4 WEEKS. LUNG TISSUES OF THE MICE WERE COLLECTED FOR GENOME-WIDE DNA METHYLATION ANALYSIS BY LIQUID HYBRIDIZATION CAPTURE-BASED BISULFITE SEQUENCING, WHICH WERE USED FOR INTERSECTION ANALYSIS WITH GENE EXPRESSION BY CDNA MICROARRAY TO IDENTIFY CANDIDATE METHYLATED GENES. THEN, FUNCTIONAL ENRICHMENT ANALYSES WITH PROTEIN-PROTEIN INTERACTION (PPI) NETWORK REGARDING THESE GENES WERE CONDUCTED TO EXPLORE THE POTENTIAL MECHANISMS. RESULTS: AFTER 4-WEEK CS EXPOSURE, THE LEVEL OF DNA METHYLATION ACCOMPANIED BY A SUBACUTE AIRWAY INFLAMMATION WAS MARKEDLY ENHANCED, AND 2002 DIFFERENTIALLY METHYLATED GENES (DMGS) WERE ANNOTATED, INCLUDING 565 DMGS CONTAINED METHYLATIONS IN GENE PROMOTERS, WHICH WERE USED FOR INTERSECTION WITH THE DIFFERENTIALLY EXPRESSED GENES. THEN, 135 CANDIDATE METHYLATED GENES WERE FURTHER SELECTED BY THE INTERSECTION, AMONG WHICH 58 GENES WITH FUNCTIONAL METHYLATED MODIFICATION WERE FINALLY IDENTIFIED. FURTHER ANALYSES REVEALED CANDIDATE METHYLATED GENES WERE SIGNIFICANTLY ENRICHED IN A COMPLICATED NETWORK OF SIGNALS AND PROCESSES, INCLUDING INTERLEUKINS, TOLL-LIKE RECEPTORS, T-CELLS DIFFERENTIATION, OXIDATIVE STRESS, MAST CELLS ACTIVATION, STEM CELLS PROLIFERATION, ETC., AS WELL AS THE 58 FUNCTIONAL METHYLATED GENES WERE PARTIALLY LOCATED AT KEY POSITIONS IN PPI NETWORK, ESPECIALLY CXCL1, DDX58 AND JAK3. CONCLUSION: THIS STUDY SUGGESTS CS EXPOSURE SIGNIFICANTLY ENHANCES DNA METHYLATED LEVEL, AND THE POTENTIAL FUNCTIONAL METHYLATED GENES ARE CLOSELY RELATED TO COMPLICATED INFLAMMATORY-IMMUNE RESPONSES, WHICH MAY PROVIDE SOME NEW EXPERIMENTAL EVIDENCE IN UNDERSTANDING THE EPIGENETIC MECHANISMS OF CS-INDUCED AIRWAY INFLAMMATION IN COPD. 2022 13 274 24 AGE-RELATED CHANGES IN DNA METHYLATION AFFECT RENAL HISTOLOGY AND POST-TRANSPLANT FIBROSIS. DURING AGEING, KIDNEY FUNCTION DECREASES DUE TO RENAL TUBULAR ATROPHY, INTERSTITIAL FIBROSIS, GLOMERULOSCLEROSIS AND ARTERIOSCLEROSIS. RECENTLY, CHANGES IN DNA METHYLATION WERE SHOWN TO CONTRIBUTE TO VARIOUS AGEING PROCESSES. HOWEVER, IT IS UNKNOWN WHETHER SUCH CHANGES ALSO CONTRIBUTE TO AGE-RELATED KIDNEY DYSFUNCTION. TO ASSESS THIS, WE PROFILED GENOME-WIDE CHANGES IN DNA METHYLATION (OVER 800 000 CPG SITES) IN 95 RENAL BIOPSIES OBTAINED PRIOR TO KIDNEY TRANSPLANTATION FROM DONORS AGED 16 TO 73 YEARS. DONOR AGE SIGNIFICANTLY ASSOCIATED WITH THE METHYLATION OF 92 778 CPGS (FALSE DISCOVERY RATE UNDER 0.05), CORRESPONDING TO 10 285 DIFFERENTIALLY METHYLATED REGIONS. THESE REGIONS WERE MOST FREQUENTLY LOCATED IN GENES INVOLVED IN THE WNT/BETA-CATENIN SIGNALING PATHWAY. USING AN INDEPENDENT COHORT OF 67 BIOPSIES, WE AUTONOMOUSLY VALIDATED THESE FINDINGS. INTERESTINGLY, THE METHYLATION STATUS OF THESE 92 778 AGE-RELATED CPGS WAS ASSOCIATED WITH GLOMERULOSCLEROSIS (34.4% OF CPGS AT A FALSE DISCOVERY RATE UNDER 0.05) AND INTERSTITIAL FIBROSIS (0.9%) AND GRAFT FUNCTION AT ONE YEAR AFTER TRANSPLANTATION, BUT NOT WITH TUBULAR ATROPHY AND ARTERIOSCLEROSIS. NO ASSOCIATION WAS OBSERVED WITH ANY OF THESE PATHOLOGIES AT THE TIME OF TRANSPLANTATION (0% AT A FALSE DISCOVERY RATE UNDER 0.05). THUS, AGE-ASSOCIATED CHANGES IN DNA METHYLATION AT THE TIME OF TRANSPLANTATION PREDICT FUTURE INJURY OF TRANSPLANTED KIDNEYS. SPECIFICALLY, OUR EPIGENOME-WIDE ASSOCIATION STUDY DEMONSTRATES THAT EPIGENETIC RENAL AGEING IS IMPLICATED IN PROGRESSIVE FIBROSIS IN BOTH THE GLOMERULUS AND THE INTERSTITIUM. 2019 14 1345 31 DETECTION OF DIFFERENTIALLY METHYLATED REGIONS USING BAYES FACTOR FOR ORDINAL GROUP RESPONSES. RESEARCHERS IN GENOMICS ARE INCREASINGLY INTERESTED IN EPIGENETIC FACTORS SUCH AS DNA METHYLATION, BECAUSE THEY PLAY AN IMPORTANT ROLE IN REGULATING GENE EXPRESSION WITHOUT CHANGES IN THE DNA SEQUENCE. THERE HAVE BEEN SIGNIFICANT ADVANCES IN DEVELOPING STATISTICAL METHODS TO DETECT DIFFERENTIALLY METHYLATED REGIONS (DMRS) ASSOCIATED WITH BINARY DISEASE STATUS. MOST OF THESE METHODS ARE BEING DEVELOPED FOR DETECTING DIFFERENTIAL METHYLATION RATES BETWEEN CASES AND CONTROLS. WE CONSIDER MULTIPLE SEVERITY LEVELS OF DISEASE, AND DEVELOP A BAYESIAN STATISTICAL METHOD TO DETECT THE REGION WITH INCREASING (OR DECREASING) METHYLATION RATES AS THE DISEASE SEVERITY INCREASES. PATIENTS ARE CLASSIFIED INTO MORE THAN TWO GROUPS, BASED ON THE DISEASE SEVERITY (E.G., STAGES OF CANCER), AND DMRS ARE DETECTED BY USING MOVING WINDOWS ALONG THE GENOME. WITHIN EACH WINDOW, THE BAYES FACTOR IS CALCULATED TO TEST THE HYPOTHESIS OF MONOTONIC INCREASE IN METHYLATION RATES CORRESPONDING TO SEVERITY OF THE DISEASE VERSUS NO DIFFERENCE. A MIXED-EFFECT MODEL IS USED TO INCORPORATE THE CORRELATION OF METHYLATION RATES OF NEARBY CPG SITES IN THE REGION. RESULTS FROM EXTENSIVE SIMULATION INDICATE THAT OUR PROPOSED METHOD IS STATISTICALLY VALID AND REASONABLY POWERFUL. WE DEMONSTRATE OUR APPROACH ON A BISULFITE SEQUENCING DATASET FROM A CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) STUDY. 2019 15 1537 30 DNA METHYLATION IN ADOLESCENTS WITH ANXIETY DISORDER: A LONGITUDINAL STUDY. ANXIETY DISORDERS (AD) TYPICALLY MANIFEST IN CHILDREN AND ADOLESCENTS AND MIGHT PERSIST INTO ADULTHOOD. HOWEVER, THERE ARE STILL FEW DATA CONCERNING EPIGENETIC MECHANISMS ASSOCIATED WITH ONSET, PERSISTENCE OR REMISSION OF AD OVER TIME. WE INVESTIGATED A COHORT OF ADOLESCENTS AND YOUNG ADULTS AT BASELINE (AGE; 13.19 +/- 2.38) AND AFTER 5 YEARS AND CLASSIFIED THEM ACCORDING TO THE AD DIAGNOSIS AND THEIR LONGITUDINAL TRAJECTORIES INTO 4 GROUPS: (1) TYPICALLY DEVELOPING COMPARISONS (TDC; CONTROL GROUP, N = 14); (2) INCIDENT (AD IN THE SECOND EVALUATION ONLY, N = 11); (3) PERSISTENT (AD IN BOTH EVALUATIONS, N = 14) AND (4) REMITTENT (AD IN THE FIRST EVALUATION ONLY, N = 8). DNA METHYLATION WAS EVALUATED WITH THE INFINIUM HUMANMETHYLATION450 BEADCHIP FROM SALIVA SAMPLES COLLECTED AT BOTH EVALUATIONS. GENE SET ENRICHMENT ANALYSIS WAS APPLIED TO CONSIDER BIOLOGICAL PATHWAYS. WE FOUND DECREASED DNA METHYLATION IN TDC GROUP WHILE THE CHRONIC CASES OF AD PRESENTED HYPERMETHYLATION IN CENTRAL NERVOUS SYSTEM DEVELOPMENT PATHWAYS. MOREOVER, WE SHOWED THAT THIS PERSISTENT GROUP ALSO PRESENTED HYPERMETHYLATION WHILE THE OTHER THREE GROUPS WERE ASSOCIATED WITH HYPOMETHYLATION IN NERVOUS SYSTEM DEVELOPMENT PATHWAY. INCIDENCE AND REMISSION GROUPS WERE ASSOCIATED WITH INCREASED AND DECREASED METHYLATION IN NEURON DEVELOPMENT PATHWAYS, RESPECTIVELY. LARGER STUDIES ARE LIKELY TO DETECT SPECIFIC GENES RELEVANT TO AD. 2018 16 4255 28 METHYLOME-WIDE ANALYSIS OF CHRONIC HIV INFECTION REVEALS FIVE-YEAR INCREASE IN BIOLOGICAL AGE AND EPIGENETIC TARGETING OF HLA. HIV-INFECTED INDIVIDUALS ARE LIVING LONGER ON ANTIRETROVIRAL THERAPY, BUT MANY PATIENTS DISPLAY SIGNS THAT IN SOME WAYS RESEMBLE PREMATURE AGING. TO INVESTIGATE AND QUANTIFY THE IMPACT OF CHRONIC HIV INFECTION ON AGING, WE REPORT A GLOBAL ANALYSIS OF THE WHOLE-BLOOD DNA METHYLOMES OF 137 HIV+ INDIVIDUALS UNDER SUSTAINED THERAPY ALONG WITH 44 MATCHED HIV- INDIVIDUALS. FIRST, WE DEVELOP AND VALIDATE EPIGENETIC MODELS OF AGING THAT ARE INDEPENDENT OF BLOOD CELL COMPOSITION. USING THESE MODELS, WE FIND THAT BOTH CHRONIC AND RECENT HIV INFECTION LEAD TO AN AVERAGE AGING ADVANCEMENT OF 4.9 YEARS, INCREASING EXPECTED MORTALITY RISK BY 19%. IN ADDITION, SUSTAINED INFECTION RESULTS IN GLOBAL DEREGULATION OF THE METHYLOME ACROSS >80,000 CPGS AND SPECIFIC HYPOMETHYLATION OF THE REGION ENCODING THE HUMAN LEUKOCYTE ANTIGEN LOCUS (HLA). WE FIND THAT DECREASED HLA METHYLATION IS PREDICTIVE OF LOWER CD4 / CD8 T CELL RATIO, LINKING MOLECULAR AGING, EPIGENETIC REGULATION, AND DISEASE PROGRESSION. 2016 17 6083 34 THE EFFECT OF SMOKING ON DNA METHYLATION OF PERIPHERAL BLOOD MONONUCLEAR CELLS FROM AFRICAN AMERICAN WOMEN. BACKGROUND: REGULAR SMOKING IS ASSOCIATED WITH A WIDE VARIETY OF SYNDROMES WITH PROMINENT INFLAMMATORY COMPONENTS SUCH AS CANCER, OBESITY AND TYPE 2 DIABETES. HEAVY REGULAR SMOKING IS ALSO ASSOCIATED WITH CHANGES IN THE DNA METHYLATION OF PERIPHERAL MONONUCLEAR CELLS. HOWEVER, IN YOUNGER SMOKERS, INFLAMMATORY EPIGENETIC FINDINGS ARE LARGELY ABSENT WHICH SUGGESTS THE INFLAMMATORY RESPONSE(S) TO SMOKING MAY BE DOSE DEPENDENT. TO HELP UNDERSTAND WHETHER PERIPHERAL MONONUCLEAR CELLS HAVE A ROLE IN MEDIATING THESE RESPONSES IN OLDER SMOKERS WITH HIGHER CUMULATIVE SMOKE EXPOSURE, WE EXAMINED GENOME-WIDE DNA METHYLATION IN A GROUP OF WELL CHARACTERIZED ADULT AFRICAN AMERICAN SUBJECTS INFORMATIVE FOR SMOKING, AS WELL AS SERUM C-REACTIVE PROTEIN (CRP) AND INTERLEUKIN-6 RECEPTOR (IL6R) LEVELS. IN ADDITION, COMPLEMENTARY BIOINFORMATIC ANALYSES WERE CONDUCTED TO DELINEATE POSSIBLE PATHWAYS AFFECTED BY LONG-TERM SMOKING. RESULTS: GENOME-WIDE DNA METHYLATION ANALYSIS WITH RESPECT TO SMOKING STATUS YIELDED 910 SIGNIFICANT LOCI AFTER BENJAMINI-HOCHBERG CORRECTION. IN PARTICULAR, TWO LOCI FROM THE AHRR GENE (CG05575921 AND CG23576855) AND ONE LOCUS FROM THE GPR15 GENE (CG19859270) WERE IDENTIFIED AS HIGHLY SIGNIFICANTLY DIFFERENTIALLY METHYLATED BETWEEN SMOKERS AND NON-SMOKERS. THE BIOINFORMATIC ANALYSES SHOWED THAT LONG-TERM CHRONIC SMOKING IS ASSOCIATED WITH ALTERED PROMOTER DNA METHYLATION OF GENES CODING FOR PROTEINS MAPPING TO CRITICAL SUB-NETWORKS MODERATING INFLAMMATION, IMMUNE FUNCTION, AND COAGULATION. CONCLUSIONS: WE CONCLUDE THAT CHRONIC REGULAR SMOKING IS ASSOCIATED WITH CHANGES IN PERIPHERAL MONONUCLEAR CELL METHYLATION SIGNATURE WHICH PERTURB INFLAMMATORY AND IMMUNE FUNCTION PATHWAYS AND MAY CONTRIBUTE TO INCREASED VULNERABILITY FOR COMPLEX ILLNESSES WITH INFLAMMATORY COMPONENTS. 2014 18 287 24 AGING AND CHRONIC SUN EXPOSURE CAUSE DISTINCT EPIGENETIC CHANGES IN HUMAN SKIN. EPIGENETIC CHANGES ARE WIDELY CONSIDERED TO PLAY AN IMPORTANT ROLE IN AGING, BUT EXPERIMENTAL EVIDENCE TO SUPPORT THIS HYPOTHESIS HAS BEEN SCARCE. WE HAVE USED ARRAY-BASED ANALYSIS TO DETERMINE GENOME-SCALE DNA METHYLATION PATTERNS FROM HUMAN SKIN SAMPLES AND TO INVESTIGATE THE EFFECTS OF AGING, CHRONIC SUN EXPOSURE, AND TISSUE VARIATION. OUR RESULTS REVEAL A HIGH DEGREE OF TISSUE SPECIFICITY IN THE METHYLATION PATTERNS AND ALSO SHOWED VERY LITTLE INTERINDIVIDUAL VARIATION WITHIN TISSUES. DATA STRATIFICATION BY AGE REVEALED THAT DNA FROM OLDER INDIVIDUALS WAS CHARACTERIZED BY A SPECIFIC HYPERMETHYLATION PATTERN AFFECTING LESS THAN 1% OF THE MARKERS ANALYZED. INTERESTINGLY, STRATIFICATION BY SUN EXPOSURE PRODUCED A FUNDAMENTALLY DIFFERENT PATTERN WITH A SIGNIFICANT TREND TOWARDS HYPOMETHYLATION. OUR RESULTS THUS IDENTIFY DEFINED AGE-RELATED DNA METHYLATION CHANGES AND SUGGEST THAT THESE ALTERATIONS MIGHT CONTRIBUTE TO THE PHENOTYPIC CHANGES ASSOCIATED WITH SKIN AGING. 2010 19 3652 27 INDIVIDUAL DNA METHYLATION PATTERN SHIFTS IN NANOPARTICLES-EXPOSED WORKERS ANALYZED IN FOUR CONSECUTIVE YEARS. A DNA METHYLATION PATTERN REPRESENTS AN ORIGINAL PLAN OF THE FUNCTION SETTINGS OF INDIVIDUAL CELLS AND TISSUES. THE BASIC STRATEGIES OF ITS DEVELOPMENT AND CHANGES DURING THE HUMAN LIFETIME ARE KNOWN, BUT THE DETAILS RELATED TO ITS MODIFICATION OVER THE YEARS ON AN INDIVIDUAL BASIS HAVE NOT YET BEEN STUDIED. MOREOVER, CURRENT EVIDENCE SHOWS THAT ENVIRONMENTAL EXPOSURE COULD GENERATE CHANGES IN DNA METHYLATION SETTINGS AND, SUBSEQUENTLY, THE FUNCTION OF GENES. IN THIS STUDY, WE ANALYZED THE EFFECT OF CHRONIC EXPOSURE TO NANOPARTICLES (NP) IN OCCUPATIONALLY EXPOSED WORKERS REPEATEDLY SAMPLED IN FOUR CONSECUTIVE YEARS (2016-2019). A DETAILED METHYLATION PATTERN ANALYSIS OF 14 PERSONS (10 EXPOSED AND 4 CONTROLS) WAS PERFORMED ON AN INDIVIDUAL BASIS. A MICROARRAY-BASED APPROACH USING CHIPS, ALLOWING THE ASSESSMENT OF MORE THAN 850 K CPG LOCI, WAS USED. INDIVIDUAL DNA METHYLATION PATTERNS WERE COMPARED BY PRINCIPAL COMPONENT ANALYSIS (PCA). THE RESULTS SHOW THE SHIFT IN DNA METHYLATION PATTERNS IN INDIVIDUAL YEARS IN ALL THE EXPOSED AND CONTROL SUBJECTS. THE OVERALL RANGE OF DIFFERENCES VARIED BETWEEN THE YEARS IN INDIVIDUAL PERSONS. THE DIFFERENCES BETWEEN THE FIRST AND LAST YEAR OF EXAMINATION (A THREE-YEAR TIME PERIOD) SEEM TO BE CONSISTENTLY GREATER IN THE NP-EXPOSED SUBJECTS IN COMPARISON WITH THE CONTROLS. THE SELECTED 14 MOST DIFFERENTLY METHYLATED CG LOCI WERE RELATIVELY STABLE IN THE CHRONICALLY EXPOSED SUBJECTS. IN SUMMARY, THE SPECIFIC TYPE OF LONG-TERM EXPOSURE CAN CONTRIBUTE TO THE FIXING OF RELEVANT EPIGENETIC CHANGES RELATED TO A SPECIFIC ENVIRONMENT AS, E.G., NP INHALATION. 2021 20 1506 35 DNA METHYLATION AND IMMUNE CELL MARKERS DEMONSTRATE EVIDENCE OF ACCELERATED AGING IN PATIENTS WITH CHRONIC HEPATITIS B VIRUS OR HEPATITIS C VIRUS, WITH OR WITHOUT HUMAN IMMUNODEFICIENCT VIRUS CO-INFECTION. BACKGROUND: SEVERAL CHRONIC DISEASES ACCELERATE BIOLOGICAL AGING. WE INVESTIGATED AGE ACCELERATION AND THE ASSOCIATION BETWEEN PERIPHERAL BLOOD DNA METHYLATION (DNAM) AND IMMUNE CELL MARKERS IN PATIENTS CHRONICALLY INFECTED WITH THE HEPATITIS B VIRUS (HBV) OR THE HEPATITIS C VIRUS (HCV) WITH AND WITHOUT HUMAN IMMUNODEFICIENCY VIRUS (HIV) CO-INFECTION. METHODS: AGE ACCELERATION WAS MEASURED AS THE DIFFERENCE BETWEEN EPIGENETIC AGE (HORVATH CLOCK) AND CHRONOLOGICAL AGE. THE IMMUNE MARKER MODEL OF AGE ACCELERATION WAS DEVELOPED USING ELASTIC NET REGRESSION TO SELECT BOTH THE IMMUNE MARKERS AND THEIR ASSOCIATED WEIGHTS IN THE FINAL LINEAR MODEL. RESULTS: PATIENTS WITH CHRONIC HBV (N = 51) HAD A SIGNIFICANTLY HIGHER MEDIAN EPIGENETIC AGE COMPARED TO CHRONOLOGICAL AGE (AGE ACCELERATED) (P < .001). IN PATIENTS WITH CHRONIC HCV INFECTION (N = 63), AGE ACCELERATION WAS ASSOCIATED WITH LIVER FIBROSIS AS ASSESSED BY HISTOLOGY (P < .05), OR PRESENCE OF HIV CO-INFECTION (P < .05), BUT NOT HCV MONO-INFECTION. AGE ACCELERATION DEFINED BY IMMUNE MARKERS WAS CONCORDANT WITH AGE ACCELERATION BY DNA METHYLATION (CORRELATION COEFFICIENT = .59 IN HBV; P = .0025). ONE-YEAR TREATMENT OF HBV PATIENTS WITH NUCLEOSIDE THERAPY WAS ASSOCIATED WITH A MODEST REDUCTION IN AGE ACCELERATION, AS MEASURED USING THE IMMUNE MARKER MODEL (-.65 YEARS, P = .018). CONCLUSION: OUR FINDINGS SUGGEST THAT PATIENTS WITH CHRONIC VIRAL HEPATITIS HAVE ACCELERATED EPIGENETIC AGING, THAT IMMUNE MARKERS DEFINE BIOLOGICAL AGE, AND HAVE THE POTENTIAL TO ASSESS THE EFFECTS OF THERAPEUTIC INTERVENTION ON AGE ACCELERATION. 2021