Systematic Review and Meta-analysis of Peripheral Blood DNA Methylation Studies in Inflammatory Bowel Disease

BACKGROUND AND AIMS

Over the past decade, the DNA methylome has been increasingly studied in peripheral blood of inflammatory bowel disease [IBD] patients. However, a comprehensive summary and meta-analysis of peripheral blood leukocyte [PBL] DNA methylation studies has thus far not been conducted. Here, we systematically reviewed all available literature up to February 2022 and summarized the observations by means of meta-analysis.

METHODS

We conducted a systematic search and critical appraisal of IBD-associated DNA methylation studies in PBL using the biomarker-based cross-sectional studies [BIOCROSS] tool. Subsequently, we performed meta-analyses on the summary statistics obtained from epigenome-wide association studies [EWAS] that included patients with Crohn's disease [CD], ulcerative colitis [UC] and/or healthy controls [HC].

RESULTS

Altogether, we included 15 studies for systematic review. Critical appraisal revealed large methodological and outcome heterogeneity between studies. Summary statistics were obtained from four studies based on a cumulative 552 samples [177 CD, 132 UC and 243 HC]. Consistent differential methylation was identified for 256 differentially methylated probes [DMPs; Bonferroni-adjusted p ≤ 0.05] when comparing CD with HC and 103 when comparing UC with HC. Comparing IBD [CD + UC] with HC resulted in 224 DMPs. Importantly, several of the previously identified DMPs, such as VMP1/TMEM49/MIR21 and RPS6KA2, were consistently differentially methylated across all studies.

CONCLUSION

Methodological homogenization of IBD epigenetic studies is needed to allow for easier aggregation and independent validation. Nonetheless, we were able to confirm previous observations. Our results can serve as the basis for future IBD epigenetic biomarker research in PBL.

Natural History and Risk Stratification of Recurrent Crohn's Disease After Ileocolonic Resection: A Multicenter Retrospective Cohort Study

BACKGROUND

Prediction of endoscopic postoperative recurrence (POR) and prophylactic treatment based on clinical risk profile have thus far been inconclusive. This study aimed to examine the association between clinical risk profile and the development of endoscopic POR in a Crohn's disease population without postoperative treatment and to identify individual risk factors of endoscopic POR.

METHODS

Medical records of 142 patients with Crohn's disease during follow-up after ileocecal or ileocolonic resection without prophylactic treatment at 3 referral centers were reviewed. Endoscopic POR was defined as a modified Rutgeerts score ≥i2b. Clinical risk profiles were distilled from current guidelines. Both uni- and multivariate logistic regression analysis were used to assess the relationship between risk profiles and endoscopic POR.

RESULTS

Endoscopic POR was observed in 68 out of 142 (47.9%) patients. Active smoking postsurgery (odds ratio [OR], 3.01; 95% confidence interval [CI], 1.24-7.34; P = 0.02), a Montreal classification of A3 (OR, 3.05; 95% CI, 1.07-8.69; P = 0.04), and previous bowel resections (OR, 2.58; 95% CI, 1.07-6.22; P = 0.03) were significantly associated with endoscopic POR. No significant association was observed between endoscopic POR and any guideline defined as a high-/low-risk profile. However, patients with a combination of any 3 or more European Crohns & Colitis Organisation- (OR, 4.87; 95% CI, 1.30-18.29; P = 0.02) or British Society of Gastroenterology-defined (OR 3.16; 95% CI, 1.05-9.49; P = 0.04) risk factors showed increased odds of developing endoscopic POR.

CONCLUSIONS

Our results suggest that patients with a combination of any 3 or more European Crohns & Colitis Organisation- or British Society of Gastroenterology-defined risk factors would probably benefit from immediate prophylactic treatment.

Long-term Temporal Stability of Peripheral Blood DNA Methylation Profiles in Patients With Inflammatory Bowel Disease

BACKGROUND & AIMS

There is great current interest in the potential application of DNA methylation alterations in peripheral blood leukocytes (PBLs) as biomarkers of susceptibility, progression, and treatment response in inflammatory bowel disease (IBD). However, the intra-individual stability of PBL methylation in IBD has not been characterized. Here, we studied the long-term stability of all probes located on the Illumina HumanMethylation EPIC BeadChip array.

METHODS

We followed a cohort of 46 adult patients with IBD (36 Crohn's disease [CD], 10 ulcerative colitis [UC]; median age, 44 years; interquartile range [IQR] 27-56 years; 50% female) that received standard care follow-up at the Amsterdam University Medical Centers. Paired PBL samples were collected at 2 time points with a median of 7 years (range, 2-9 years) in between. Differential methylation and intra-class correlation (ICC) analyses were used to identify time-associated differences and temporally stable CpGs, respectively.

RESULTS

Around 60% of all EPIC array loci presented poor intra-individual stability (ICC <0.50); 78.114 (≈9%) showed good (ICC, 0.75-0.89), and 41.274 (≈5%) showed excellent (ICC ≥0.90) stability, between both measured time points. Focusing on previously identified consistently differentially methylated positions indicated that 22 CD-, 11 UC-, and 24 IBD-associated loci demonstrated high stability (ICC ≥0.75) over time; of these, we observed a marked stability of CpG loci associated to the HLA genes.

CONCLUSIONS

Our data provide insight into the long-term stability of the PBL DNA methylome within an IBD context, facilitating the selection of biologically relevant and robust IBD-associated epigenetic biomarkers with increased potential for independent validation. These data also have potential implications in understanding disease pathogenesis.

Benefit of risk-stratified prophylactic treatment on clinical outcome in post-operative Crohn's disease

BACKGROUND AND AIMS

While immediate post-operative treatment has shown effectiveness in reducing endoscopic post-operative recurrence (POR), evidence regarding the clinical benefit is limited. We compared rates of clinical POR in Crohn's disease (CD) patients receiving immediate prophylactic treatment with patients receiving endoscopy-driven treatment.

METHODS

We retrospectively collected data from 376 consecutive CD patients that underwent an ileocecal resection with anastomosis between 2007 and 2018 with at least 3 years of follow-up at 3 sites. Subsequently, high- and low-risk patients categorized by established guidelines who underwent endoscopy within 12 months postoperatively were grouped according to a prophylactic- or endoscopy-driven approach and compared for incidence and time till endoscopic- and clinical POR.

RESULTS

Prophylactic treatment reduced rates of- and time till endoscopic POR within 1 year in high-risk (HR 0.48, 95% CI 0.27-0.86, p=0.04, NNT=5) but not low-risk (HR 0.90, 95%CI 0.32-2.56, p=0.85) patients. Conversely, no significant differences in clinical POR within 3 years between prophylactic- and endoscopy-driven low-risk (HR 1.17, 95%CI 0.41-3.29, p=0.75) and high-risk patients were observed (HR 1.06, 95%CI 0.63-1.79, p=0.82, NNT=22). However, a large numerical albeit not statistical significant difference in 3 year clinical POR (28.6% vs. 62.5%, p=0.11) in a subset of high-risk patients with ≥3 or more ECCO-defined risk factors was observed, indicating a cumulative effect of having multiple risk factors.

CONCLUSION

Our observations favor step-up treatment guided by early endoscopic evaluation with prophylactic treatment reserved for carefully selected high-risk patients in order to avoid potential overtreatment of a significant number of patients.

Peripheral Blood DNA Methylation Signatures and Response to Tofacitinib in Moderate-to-severe Ulcerative Colitis

INTRODUCTION

Predictive biomarkers for treatment efficacy of ulcerative colitis [UC] treatments are lacking. Here, we performed a longitudinal study investigating the association and potential predictive power of genome-wide peripheral blood [PB] DNA methylation signatures and response to tofacitinib treatment in UC.

METHODS

We recruited moderate-to-severe UC patients starting tofacitinib treatment, and measured PB DNA methylation profiles at baseline [T1], after 8 weeks [T2], and in a subset [n = 8] after a median of 20 weeks [T3] using the Illumina Infinium HumanMethylation EPIC BeadChip. After 8 weeks, we distinguished responders [R] from non-responders [NR] based on a centrally read endoscopic response [decrease in endoscopic Mayo score ≥1 or Ulcerative Colitis Endoscopic Index of Severity ≥2] combined with corticosteroid-free clinical and/or biochemical response. T1 PB samples were used for biomarker identification, and T2 and publicly available intraclass correlation [ICC] data were used for stability analyses. RNA-sequencing was performed to understand the downstream effects of the predictor CpG loci.

RESULTS

In total, 16 R and 15 NR patients, with a median disease duration of 7 [4-12] years and overall comparable patient characteristics at baseline, were analysed. We identified a panel of 53 differentially methylated positions [DMPs] associated with response to tofacitinib [AUROC 0.74]. Most DMPs [77%] demonstrated both short- and long-term hyperstability [ICC ≥0.90], irrespective of inflammatory status. Gene expression analysis showed lower FGFR2 [pBH = 0.011] and LRPAP1 [pBH = 0.020], and higher OR2L13 [pBH = 0.016] expression at T1 in R compared with NR.

CONCLUSION

Our observations demonstrate the utility of genome-wide PB DNA methylation signatures to predict response to tofacitinib.

Novel DNA methylome biomarkers associated with adalimumab response in rheumatoid arthritis patients

Background and aims

Rheumatoid arthritis (RA) patients are currently treated with biological agents mostly aimed at cytokine blockade, such as tumor necrosis factor-alpha (TNFα). Currently, there are no biomarkers to predict therapy response to these agents. Here, we aimed to predict response to adalimumab (ADA) treatment in RA patients using DNA methylation in peripheral blood (PBL).

Methods

DNA methylation profiling on whole peripheral blood from 92 RA patients before the start of ADA treatment was determined using Illumina HumanMethylationEPIC BeadChip array. After 6 months, treatment response was assessed according to the European Alliance of Associations for Rheumatology (EULAR) criteria for disease activity. Patients were classified as responders (Disease Activity Score in 28 Joints (DAS28) < 3.2 or decrease of 1.2 points) or as non-responders (DAS28 > 5.1 or decrease of less than 0.6 points). Machine learning models were built through stability-selected gradient boosting to predict response prior to ADA treatment with predictor DNA methylation markers.

Results

Of the 94 RA patients, we classified 49 and 43 patients as responders and non-responders, respectively. We were capable of differentiating responders from non-responders with a high performance (area under the curve (AUC) 0.76) using a panel of 27 CpGs. These classifier CpGs are annotated to genes involved in immunological and pathophysiological pathways related to RA such as T-cell signaling, B-cell pathology, and angiogenesis.

Conclusion

Our findings indicate that the DNA methylome of PBL provides discriminative capabilities in discerning responders and non-responders to ADA treatment and may therefore serve as a tool for therapy prediction.

The Clinical Relevance of an Inflamed Appendix in Crohn's Disease

BACKGROUND AND AIMS

An appendectomy for appendiceal inflammation has been suggested to ameliorate the clinical course of patients with ulcerative colitis [UC]. In contrast, for Crohn's disease [CD] an inverse association has been suggested with a higher incidence of CD and worse prognosis after appendectomy. The aim of this study was to analyse the clinical relevance of an inflamed appendix in CD patients undergoing ileocaecal resection [ICR].

METHODS

All consecutive patients undergoing primary ICR between 2007 and 2018 were considered for inclusion. Microscopic data of available appendiceal resection specimens [n = 99] were revised by a dedicated inflammatory bowel disease [IBD] pathologist and scored as inflamed or not inflamed. Eighteen patients had a previous appendectomy. Pathological findings were correlated with disease characteristics and recurrence rates [clinical, endoscopic, and intervention-related].

RESULTS

In total 117 patients were included, 77 [65.8%] females, with a median age of 30 years (interquartile range [IQR] 24-43), and a median follow up of 102 months [IQR 76-114]. Of patients without previous appendectomy [n = 99], 39% had an inflamed appendix. No significant differences in disease characteristics [eg, disease location, behaviour, time to surgery] or prognosis could be demonstrated between the two groups. In contrast, previous appendectomy [n = 18] was associated with penetrating disease and numerically shorter disease duration at the time of resection. Furthermore, a trend was seen towards a stronger association with postoperative recurrence.

CONCLUSION

The current study could not confirm a different prognosis for CD patients with and without an inflamed appendix. In contrast, in patients with a previous appendectomy, a trend was seen towards increased postoperative recurrence, which might be related to the higher incidence of penetrating disease.