In the past decade, there have been fundamental advances in our understanding of genetic factors that contribute to the inflammatory bowel diseases (IBDs) Crohn’s disease and ulcerative colitis. The ...latest international collaborative studies have brought the number of IBD susceptibility gene loci to 163. However, genetic factors account for only a portion of overall disease variance, indicating a need to better explore gene-environment interactions in the development of IBD. Epigenetic factors can mediate interactions between the environment and the genome; their study could provide new insight into the pathogenesis of IBD. We review recent progress in identification of genetic factors associated with IBD and discuss epigenetic mechanisms that could affect development and progression of IBD.
Determining bacterial community structure in fecal samples through DNA sequencing is an important facet of intestinal health research. The impact of different commercially available DNA extraction ...kits upon bacterial community structures has received relatively little attention. The aim of this study was to analyze bacterial communities in volunteer and inflammatory bowel disease (IBD) patient fecal samples extracted using widely used DNA extraction kits in established gastrointestinal research laboratories.
Fecal samples from two healthy volunteers (H3 and H4) and two relapsing IBD patients (I1 and I2) were investigated. DNA extraction was undertaken using MoBio Powersoil and MP Biomedicals FastDNA SPIN Kit for Soil DNA extraction kits. PCR amplification for pyrosequencing of bacterial 16S rRNA genes was performed in both laboratories on all samples. Hierarchical clustering of sequencing data was done using the Yue and Clayton similarity coefficient.
DNA extracted using the FastDNA kit and the MoBio kit gave median DNA concentrations of 475 (interquartile range 228-561) and 22 (IQR 9-36) ng/µL respectively (p<0.0001). Hierarchical clustering of sequence data by Yue and Clayton coefficient revealed four clusters. Samples from individuals H3 and I2 clustered by patient; however, samples from patient I1 extracted with the MoBio kit clustered with samples from patient H4 rather than the other I1 samples. Linear modelling on relative abundance of common bacterial families revealed significant differences between kits; samples extracted with MoBio Powersoil showed significantly increased Bacteroidaceae, Ruminococcaceae and Porphyromonadaceae, and lower Enterobacteriaceae, Lachnospiraceae, Clostridiaceae, and Erysipelotrichaceae (p<0.05).
This study demonstrates significant differences in DNA yield and bacterial DNA composition when comparing DNA extracted from the same fecal sample with different extraction kits. This highlights the importance of ensuring that samples in a study are prepared with the same method, and the need for caution when cross-comparing studies that use different methods.
Ulcerative colitis and Crohn's disease are the principal forms of inflammatory bowel disease. Both represent chronic inflammation of the gastrointestinal tract, which displays heterogeneity in ...inflammatory and symptomatic burden between patients and within individuals over time. Optimal management relies on understanding and tailoring evidence-based interventions by clinicians in partnership with patients. This guideline for management of inflammatory bowel disease in adults over 16 years of age was developed by Stakeholders representing UK physicians (British Society of Gastroenterology), surgeons (Association of Coloproctology of Great Britain and Ireland), specialist nurses (Royal College of Nursing), paediatricians (British Society of Paediatric Gastroenterology, Hepatology and Nutrition), dietitians (British Dietetic Association), radiologists (British Society of Gastrointestinal and Abdominal Radiology), general practitioners (Primary Care Society for Gastroenterology) and patients (Crohn's and Colitis UK). A systematic review of 88 247 publications and a Delphi consensus process involving 81 multidisciplinary clinicians and patients was undertaken to develop 168 evidence- and expert opinion-based recommendations for pharmacological, non-pharmacological and surgical interventions, as well as optimal service delivery in the management of both ulcerative colitis and Crohn's disease. Comprehensive up-to-date guidance is provided regarding indications for, initiation and monitoring of immunosuppressive therapies, nutrition interventions, pre-, peri- and postoperative management, as well as structure and function of the multidisciplinary team and integration between primary and secondary care. Twenty research priorities to inform future clinical management are presented, alongside objective measurement of priority importance, determined by 2379 electronic survey responses from individuals living with ulcerative colitis and Crohn's disease, including patients, their families and friends.
Genetic association studies have identified 215 risk loci for inflammatory bowel disease, thereby uncovering fundamental aspects of its molecular biology. We performed a genome-wide association study ...of 25,305 individuals and conducted a meta-analysis with published summary statistics, yielding a total sample size of 59,957 subjects. We identified 25 new susceptibility loci, 3 of which contain integrin genes that encode proteins in pathways that have been identified as important therapeutic targets in inflammatory bowel disease. The associated variants are correlated with expression changes in response to immune stimulus at two of these genes (ITGA4 and ITGB8) and at previously implicated loci (ITGAL and ICAM1). In all four cases, the expression-increasing allele also increases disease risk. We also identified likely causal missense variants in a gene implicated in primary immune deficiency, PLCG2, and a negative regulator of inflammation, SLAMF8. Our results demonstrate that new associations at common variants continue to identify genes relevant to therapeutic target identification and prioritization.
Aims
Hypophosphataemia is an increasingly recognized side‐effect of ferric carboxymaltose (FCM) and possibly iron isomaltoside/ferric derisomaltose (IIM), which are used to treat iron deficiency. The ...aim of this study was to determine frequency, severity, duration and risk factors of incident hypophosphataemia after treatment with FCM and IIM.
Methods
A systematic literature search for articles indexed in EMBASE, PubMed and Web of Science in years 2005–2020 was carried out using the search terms ‘ferric carboxymaltose’ OR ‘iron isomaltoside’. Prospective clinical trials reporting outcomes on hypophosphataemia rate, mean nadir serum phosphate and/or change in mean serum phosphate from baseline were selected. Hypophosphataemia rate and severity were compared for studies on IIM vs. FCM after stratification for chronic kidney disease. Meta‐regression analysis was used to investigate risk factors for hypophosphataemia.
Results
Across the 42 clinical trials included in the meta‐analysis, FCM induced a significantly higher incidence of hypophosphataemia than IIM (47%, 95% CI 36–58% vs. 4%, 95% CI 2–5%), and significantly greater mean decreases in serum phosphate (0.40 vs. 0.06 mmol/L). Hypophosphataemia persisted at the end of the study periods (maximum 3 months) in up to 45% of patients treated with FCM. Meta‐regression analysis identified low baseline serum ferritin and transferrin saturation, and normal kidney function as significant predictors of hypophosphataemia.
Conclusion
FCM is associated with a high risk of hypophosphataemia, which does not resolve for at least 3 months in a large proportion of affected patients. More severe iron deficiency and normal kidney function are risk factors for hypophosphataemia.
There is an unmet need for novel blood-based biomarkers that offer timely and accurate diagnostic and prognostic testing in inflammatory bowel diseases (IBD). We aimed to investigate the diagnostic ...and prognostic utility of serum calprotectin (SC) in IBD.
A total of 171 patients (n=96 IBD, n=75 non-IBD) were prospectively recruited. A multi-biomarker model was derived using multivariable logistic regression analysis. Cox proportional hazards model was derived to assess the contribution of each variable to disease outcomes.
SC correlated strongly with current biomarkers, including fecal calprotectin (FC) (n=50, ρ=0.50, P=1.6 × 10
). SC was the strongest individual predictor of IBD diagnosis (odds ratio (OR): 9.37 (95% confidence interval (CI): 2.82-34.68), P=4.00 × 10
) compared with other markers (C-reactive protein (CRP): OR 8.52 (95% CI: 2.75-28.63), P=2.80 × 10
); albumin: OR 6.12 (95% CI: 1.82-22.16), P=0.004). In a subset of 50 patients with paired SC and FC, the area under receiver operating characteristic discriminating IBD from controls was better for FC than for SC (0.99, (95% CI 0.87-1.00) and 0.87 (95% CI:0.78-0.97), respectively; P=0.01). At follow-up (median 342 days; interquartile range: 88-563), SC predicted treatment escalation and/or surgery in IBD (hazard ratio (HR) 2.7, 95% CI: 1.1-4.9), in particular Crohn's disease (CD) (HR 4.2, 95% CI 1.2-15.3). A model incorporating SC and either CRP or albumin has a positive likelihood ratio of 24.14 for IBD. At 1 year, our prognostic model can predict treatment escalation in IBD in 65% of cases (95% CI: 43-79%) and 80% (95% CI: 31-94%) in CD if ≥2 blood marker criteria are met.
A diagnostic and prognostic model that combines SC and other blood-based biomarkers accurately predicts the inflammatory burden in IBD and has the potential to predict disease and its outcomes. Our data warrant further detailed exploration and validation in large multicenter cohorts.
Antitumour necrosis factor (anti-TNF) drugs impair protective immunity following pneumococcal, influenza and viral hepatitis vaccination and increase the risk of serious respiratory infections. We ...sought to determine whether infliximab-treated patients with IBD have attenuated serological responses to SARS-CoV-2 infections.
Antibody responses in participants treated with infliximab were compared with a reference cohort treated with vedolizumab, a gut-selective anti-integrin α4β7 monoclonal antibody that is not associated with impaired vaccine responses or increased susceptibility to systemic infections. 6935 patients were recruited from 92 UK hospitals between 22 September and 23 December 2020.
Rates of symptomatic and proven SARS-CoV-2 infection were similar between groups. Seroprevalence was lower in infliximab-treated than vedolizumab-treated patients (3.4% (161/4685) vs 6.0% (134/2250), p<0.0001). Multivariable logistic regression analyses confirmed that infliximab (vs vedolizumab; OR 0.66 (95% CI 0.51 to 0.87), p=0.0027) and immunomodulator use (OR 0.70 (95% CI 0.53 to 0.92), p=0.012) were independently associated with lower seropositivity. In patients with confirmed SARS-CoV-2 infection, seroconversion was observed in fewer infliximab-treated than vedolizumab-treated patients (48% (39/81) vs 83% (30/36), p=0.00044) and the magnitude of anti-SARS-CoV-2 reactivity was lower (median 0.8 cut-off index (0.2-5.6) vs 37.0 (15.2-76.1), p<0.0001).
Infliximab is associated with attenuated serological responses to SARS-CoV-2 that were further blunted by immunomodulators used as concomitant therapy. Impaired serological responses to SARS-CoV-2 infection might have important implications for global public health policy and individual anti-TNF-treated patients. Serological testing and virus surveillance should be considered to detect suboptimal vaccine responses, persistent infection and viral evolution to inform public health policy.
ISRCTN45176516.
The COVID-19 pandemic is putting unprecedented pressures on healthcare systems globally. Early insights have been made possible by rapid sharing of data from China and Italy. In the UK, we have ...rapidly mobilised inflammatory bowel disease (IBD) centres in order that preparations can be made to protect our patients and the clinical services they rely on. This is a novel coronavirus; much is unknown as to how it will affect people with IBD. We also lack information about the impact of different immunosuppressive medications. To address this uncertainty, the British Society of Gastroenterology (BSG) COVID-19 IBD Working Group has used the best available data and expert opinion to generate a risk grid that groups patients into highest, moderate and lowest risk categories. This grid allows patients to be instructed to follow the UK government's advice for shielding, stringent and standard advice regarding social distancing, respectively. Further considerations are given to service provision, medical and surgical therapy, endoscopy, imaging and clinical trials.
The COVID-19 pandemic has raised considerable concerns that patients with inflammatory bowel disease (IBD), particularly those treated with immunosuppressive therapies, may have an increased risk of ...SARS-CoV-2 acquisition, develop worse outcomes following COVID-19, and have suboptimal vaccine response compared with the general population. In this review, we summarise data on the risk of COVID-19 and associated outcomes, and latest guidance on SARS-CoV-2 vaccines in patients with IBD. Emerging evidence suggests that commonly used medications for IBD, such as corticosteroids but not biologicals, were associated with adverse outcomes to COVID-19. There has been no increased risk of de novo, or delayed, IBD diagnoses, however, an overall decrease in endoscopy procedures has led to a rise in the number of missed endoscopic-detected cancers during the pandemic. The impact of IBD medication on vaccine response has been a research priority recently. Data suggest that patients with IBD treated with antitumour necrosis factor (TNF) medications had attenuated humoral responses to SARS-CoV-2 vaccines, and more rapid antibody decay, compared with non-anti-TNF-treated patients. Reassuringly, rates of breakthrough infections and hospitalisations in all patients who received vaccines, irrespective of IBD treatment, remained low. International guidelines recommend that all patients with IBD treated with immunosuppressive therapies should receive, at any point during their treatment cycle, three primary doses of SARS-CoV-2 vaccines with a further booster dose as soon as possible. Future research should focus on our understanding of the rate of antibody decay in biological-treated patients, which patients require additional doses of SARS-CoV-2 vaccine, the long-term risks of COVID-19 on IBD disease course and activity, and the potential risk of long COVID-19 in patients with IBD.
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