Analysis of Systemic Epigenetic Alterations in Inflammatory Bowel Disease: Defining Geographical, Genetic and Immune-Inflammatory influences on the Circulating Methylome.

BackgroundEpigenetic alterations may provide valuable insights into gene-environment interactions in the pathogenesis of inflammatory bowel disease [IBD].MethodsGenome-wide methylation was measured from peripheral blood using the Illumina 450k platform in a case-control study in an inception cohort (295 controls, 154 Crohn's disease [CD], 161 ulcerative colitis [UC], 28 IBD unclassified [IBD-U)] with covariates of age, sex and cell counts, deconvoluted by the Houseman method. Genotyping was performed using Illumina HumanOmniExpressExome-8 BeadChips and gene expression using the Ion AmpliSeq Human Gene Expression Core Panel. Treatment escalation was characterized by the need for biological agents or surgery after initial disease remission.ResultsA total of 137 differentially methylated positions [DMPs] were identified in IBD, including VMP1/MIR21 [p = 9.11 × 10-15] and RPS6KA2 [6.43 × 10-13], with consistency seen across Scandinavia and the UK. Dysregulated loci demonstrate strong genetic influence, notably VMP1 [p = 1.53 × 10-15]. Age acceleration is seen in IBD [coefficient 0.94, p ConclusionThese data demonstrate consistent epigenetic alterations at diagnosis in European patients with IBD, providing insights into the pathogenetic importance and translational potential of epigenetic mapping in complex disease.