Postoperative small bowel Crohn's disease: how to diagnose, manage and treat.

PURPOSE OF REVIEW: Crohn's disease is a relapsing inflammatory condition and disease recurrence after surgery is common. Significant variation in clinical practice remains despite progress in management of postoperative Crohn's disease. In this review, we summarise current management strategies and guidelines, unmet needs, and research progress in this field. RECENT FINDINGS: There has been real progress in risk stratifying individuals' postsurgery and tailoring therapies based on their risk; this has been incorporated into current management guidelines in the USA, UK, and Europe. Furthermore, novel noninvasive monitoring tools such as intestinal ultrasound have shown high sensitivity and specificity at detecting disease recurrence and are an attractive point-of-care test. Recent studies are also investigating multiomic biomarkers to prognosticate postoperative Crohn's disease. However, given the heterogeneity within this condition, large multicentre clinical validation across all age groups is needed for clinical translation in the future. SUMMARY: Ongoing progress in research and the development of novel prognostic and noninvasive disease monitoring tools offers hope for personalised therapy tailored to individual recurrence risk in postoperative Crohn's disease.

Vedolizumab for induction and maintenance of remission in Crohn's disease.

BACKGROUND: Vedolizumab blocks inflammatory activity within the gastrointestinal tract. Systematic reviews have demonstrated the efficacy of vedolizumab in ulcerative colitis and inflammatory bowel disease in general. This systematic review and meta-analysis summarises the current evidence of vedolizumab in the induction and maintenance of remission in Crohn's disease. OBJECTIVES: To evaluate the benefits and harms of vedolizumab versus placebo for the induction and maintenance of remission in people with Crohn's disease. SEARCH METHODS: We used standard, extensive Cochrane search methods. The latest search date was 30 November 2022. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi-RCTs comparing vedolizumab to placebo for the induction or maintenance of remission in people with Crohn's disease. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. For induction studies, the primary outcome was 1. clinical remission, and secondary outcomes were rates of 2. clinical response, 3. adverse events, 4. serious adverse events, 5. surgery, 6. endoscopic remission and 7. endoscopic response. For maintenance studies, the primary outcome was 1. maintenance of clinical remission, and secondary outcomes were rates of 2. adverse events, 3. serious adverse events, 4. surgery, 5. endoscopic remission and 6. endoscopic response. We used GRADE to assess certainty of evidence. MAIN RESULTS: We analysed induction (4 trials, 1126 participants) and maintenance (3 trials, 894 participants) studies representing people across North America, Europe, Asia and Australasia separately. One maintenance trial administered subcutaneous vedolizumab whilst the other studies used the intravenous form. The mean age ranged between 32.6 and 38.6 years. Vedolizumab was superior to placebo for the induction of clinical remission (71 more per 1000 with clinical remission with vedolizumab; risk ratio (RR) 1.61, 95% confidence interval (CI) 1.20 to 2.17; number needed to treat for an additional beneficial outcome (NNTB) 13; 4 studies; high-certainty evidence) and superior to placebo for inducing clinical response (105 more per 1000 with clinical response with vedolizumab; RR 1.43, 95% CI 1.19 to 1.71; NNTB 8; 4 studies; high-certainty evidence). For the induction phase, vedolizumab may be equivalent to placebo for the development of serious adverse events (9 fewer serious adverse events per 1000 with vedolizumab; RR 0.91, 95% CI 0.62 to 1.33; 4 studies; low-certainty evidence) and probably equivalent to placebo for overall adverse events (6 fewer adverse events per 1000 with vedolizumab; RR 1.01, 95% CI 0.93 to 1.11; 4 studies; moderate-certainty evidence). Vedolizumab was superior to placebo for the maintenance of clinical remission (141 more per 1000 with maintenance of clinical remission with vedolizumab; RR 1.52, 95% CI 1.24 to 1.87; NNTB 7; 3 studies; high-certainty evidence). During the maintenance phase, vedolizumab may be equivalent to placebo for the development of serious adverse events (3 fewer serious adverse events per 1000 with vedolizumab; RR 0.98, 95% CI 0.68 to 1.39; 3 studies; low-certainty evidence) and probably equivalent to placebo for the development of overall adverse events (0 difference in adverse events per 1000; RR 1.00, 95% CI 0.94 to 1.07; 3 studies; moderate-certainty evidence). AUTHORS' CONCLUSIONS: High-certainty data across four induction and three maintenance trials demonstrate that vedolizumab is superior to placebo in the induction and maintenance of remission in Crohn's disease. Overall adverse events are probably similar and serious adverse events may be similar between vedolizumab and placebo during both induction and maintenance phases of treatment. Head-to-head research comparing the efficacy and safety of vedolizumab to other biological therapies is required.

Patients' perceptions of faecal calprotectin testing in inflammatory bowel disease: results from a prospective multicentre patient-based survey.

INTRODUCTION: Despite its success, there appears to be practical issues with Faecal Calprotectin (FC) testing in Inflammatory Bowel Diseases (IBD), including sample collection, delivery and processing delays. Patients' perception and barriers to FC testing are yet to be explored in clinical practice. METHOD: A prospective patient survey was undertaken at IBD units in UK, Europe and Australia. A 9-point patient-based questionnaire was completed in clinic and included demographics, previous FC testing and FC sample difficulty rating score. Predictors of testing difficulty were derived using multivariable logistic regression analysis. RESULTS: A total of 585 patients with IBD completed the survey; 306 males with a median age of 43 years (IQR: 31-54). There were 446 patients (76%) who had prior FC testing experience. Of these, 37% (n = 165) rated FC testing difficult; 'sample collection' (n = 106; 67%) being the most common reason reported. Multivariable regression analysis identified age <49 years (odds ratio (OR): 2.5, CI:1.6-4.0), disease duration <35 months (OR 1.4, CI:0.9-2.1) and testing location (UK centre: OR 1.9, CI:1.2-3.1) as predictors of a difficult FC rating score. CONCLUSIONS: A total of 37% of patients find FC testing challenging, in particular those aged <49 years, disease duration <35 months. Further studies understanding and addressing these practical issues may aid higher FC uptake in clinic.

Withdrawal of immunosuppressant or biologic therapy for patients with quiescent Crohn's disease.

BACKGROUND: Crohn's disease (CD) is a chronic, relapsing and remitting disease of the gastrointestinal tract that can cause significant morbidity and disability. Current treatment guidelines recommend early intervention with immunosuppressant or biological therapy in high-risk patients with a severe disease phenotype at presentation. The feasibility of therapeutic de-escalation once remission is achieved is a commonly encountered question in clinical practice, driven by patient and clinician concerns regarding safety, adverse events, cost and national regulations. Withdrawal of immunosuppressant and biologic drugs in patients with quiescent CD may limit adverse events and reduce healthcare costs. Alternatively, stopping these drug therapies may result in negative outcomes such as disease relapse, drug desensitization, bowel damage and need for surgery. OBJECTIVES: To assess the feasibility and safety of discontinuing immunosuppressant or biologic drugs, administered alone or in combination, in patients with quiescent CD. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase and the Cochrane IBD Group Specialized Register from inception to 19 December 2017. We also searched the reference lists of potentially relevant manuscripts and conference proceedings to identify additional studies. SELECTION CRITERIA: Randomized controlled trials (RCTs) and prospective cohort studies that followed patients for a minimum duration of six months after drug discontinuation were considered for inclusion. The patient population of interest was adults (> 18 years) with CD (as defined by conventional clinical, endoscopic or histologic criteria) who had achieved remission while receiving immunosuppressant or biologic drugs administered alone or in combination. Patients then discontinued the drug regimen following a period of maintenance therapy of at least six months. The comparison was usual care (i.e. continuation of the drug regimen). DATA COLLECTION AND ANALYSIS: The primary outcome measure was the proportion of patients who relapsed following discontinuation of immunosuppressant or biologic drugs, administered alone or in combination. Secondary outcomes included: the proportion of patients who responded to the reintroduction of immunosuppressant or biologic drugs, given as monotherapy or combination therapy; the proportion of patients who required surgery following relapse; the proportion of patients who required hospitalization for CD following relapse; the proportion of patients who developed new CD-related complications (e.g. fistula, abscesses, strictures) following relapse; the proportion of patients with elevated biomarkers of inflammation (CRP, fecal calprotectin) in those who stop and those who continue therapy; the proportion of patients with anti-drug antibodies and low serum trough drug levels; time to relapse; and the proportion of patients with adverse events, serious adverse events and withdrawal due to adverse events. For dichotomous outcomes, we calculated the risk ratio (RR) and 95% confidence interval (95% CI). Data were analyzed on an intention-to-treat basis where patients with missing outcome data were assumed to have relapsed. The overall quality of the evidence supporting the primary and secondary outcomes was assessed using the GRADE criteria. MAIN RESULTS: A total of six RCTs (326 patients) evaluating therapeutic discontinuation in patients with quiescent CD were eligible for inclusion. In four RCTs azathioprine monotherapy was discontinued, and in two RCTs azathioprine was discontinued from a combination therapy regimen consisting of azathioprine with infliximab. No studies of biologic monotherapy withdrawal were eligible for inclusion. The majority of studies received unclear or low risk of bias ratings, with the exception of three open-label RCTs, which were rated as high risk of bias for blinding. Four RCTs (215 participants) compared discontinuation to continuation of azathioprine monotherapy, while two studies (125 participants) compared discontinuation of azathioprine from a combination regimen to continuation of combination therapy. Continuation of azathioprine monotherapy was shown to be superior to withdrawal for risk of clinical relapse. Thirty-two per cent (36/111) of azathioprine withdrawal participants relapsed compared to 14% (14/104) of participants who continued with azathioprine therapy (RR 0.42, 95% CI 0.24 to 0.72, GRADE low quality evidence). However, it is uncertain if there are any between-group differences in new CD-related complications (RR 0.34, 95% CI 0.06 to 2.08, GRADE low quality evidence), adverse events (RR 0.88, 95% CI 0.67 to 1.17, GRADE low quality evidence), serious adverse events (RR 3.29, 95% CI 0.35 to 30.80, GRADE low quality evidence) or withdrawal due to adverse events (RR 2.59, 95% CI 0.35 to 19.04, GRADE low quality evidence). Common adverse events included infections, mild leukopenia, abdominal symptoms, arthralgias, headache and elevated liver enzymes. No differences between azathioprine withdrawal from combination therapy versus continuation of combination therapy were observed for clinical relapse. Among patients who continued combination therapy with azathioprine and infliximab, 48% (27/56) had a clinical relapse compared to 49% (27/55) of patients discontinued azathioprine but remained on infliximab (RR 1.02, 95% CI 0.68 to 1.52, P = 0.32; GRADE low quality evidence). The effects on adverse events (RR 1.11, 95% CI 0.44 to 2.81, GRADE low quality of evidence) or serious adverse events are uncertain (RR 1.00, 95% CI 0.21 to 4.66; GRADE very low quality of evidence). Common adverse events in the combination therapy studies included infections, liver test elevations, arthralgias and infusion reactions. AUTHORS' CONCLUSIONS: The effects of withdrawal of immunosuppressant therapy in people with quiescent Crohn's disease are uncertain. Low quality evidence suggests that continuing azathioprine monotherapy may be superior to withdrawal for avoiding clinical relapse, while very low quality evidence suggests that there may be no difference in clinical relapse rates between discontinuing azathioprine from a combination therapy regimen, compared to continuing combination therapy. It is unclear whether withdrawal of azathioprine, initially administered alone or in combination, impacts on the development of CD-related complications, adverse events, serious adverse events or withdrawal due to adverse events. Further high-quality research is needed in this area, particularly double-blind RCTs in which biologic therapy or an immunosuppressant other than azathioprine is withdrawn.

Systematic Review of Effects of Withdrawal of Immunomodulators or Biologic Agents From Patients With Inflammatory Bowel Disease.

Little is known about the optimal duration of therapy with an anti-tumor necrosis factor (TNF) agent and/or an immunomodulator for patients with inflammatory bowel disease (IBD). We performed a systematic search of the literature to identify studies reporting after de-escalation (drug cessation or dose reduction) of anti-TNF agents and/or immunomodulators in patients in remission from IBD. Studies were reviewed according to the type of IBD and drug. Rates of relapse, factors associated with relapse, and response to re-treatment were determined. Our search yielded 6315 unique citations; we analyzed findings from 69 studies (18 on de-escalation [drug cessation or dose reduction] of immunomodulator monotherapy, 8 on immunomodulator de-escalation from combination therapy, and 43 on de-escalation of anti-TNF agents, including 3 during pregnancy) comprising 4672 patients. Stopping immunomodulator monotherapy after a period of remission was associated with high rates of relapse in patients with Crohn's disease or ulcerative colitis (approximately 75% of patients experienced a relapse within 5 years after therapy was stopped). Most studies of patients with Crohn's disease who discontinued an immunomodulator after combination therapy found that rates of relapse did not differ from those of patients who continued taking the drug (55%-60% had disease relapse 24 months after they stopped taking the immunomodulator). The only study in patients with ulcerative colitis supported continued immunomodulator use. Approximately 50% of patients who discontinued anti-TNF agents after combination therapy maintained remission 24 months later, but the proportion in remission decreased with time. Markers of disease activity, poor prognostic factors, and complicated or relapsing disease course were associated with future relapse. In conclusion, based on a systematic review, 50% or more of patients with IBD who cease therapy have a disease relapse. Further studies are required to accurately identify subgroups of patients who are good candidates for discontinuation of treatment. The decision to withdraw a drug should be made for each individual based on patient preference, disease markers, consequences of relapse, safety, and cost.

Biomarkers in Search of Precision Medicine in IBD.

The completion of the human genome project in 2003 represented a major scientific landmark, ushering in a new era with hopes and expectations of fresh insights into disease mechanisms and treatments. In inflammatory bowel disease (IBD), many important discoveries soon followed, notably the identification of >200 genetic susceptibility loci and characterization of the gut microbiome. As "big data", driven by advances in technology, becomes increasingly available and affordable, individuals with IBD and clinicians alike yearn for tangible outcomes from the promise of "precision medicine"-precise diagnosis, monitoring, and treatment. Here, we provide a commentary on the prospects and challenges of precision medicine and biomarkers in IBD. We focus on the three key areas where precision IBD will have the most impact: (1) disease susceptibility, activity, and behavior; (2) prediction of drug response and adverse effects; and (3) identification of subphenotypic mechanisms to facilitate drug discovery and selection of new treatments in IBD.

Serum Calprotectin: A Novel Diagnostic and Prognostic Marker in Inflammatory Bowel Diseases.

OBJECTIVES: 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. METHODS: 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. RESULTS: SC correlated strongly with current biomarkers, including fecal calprotectin (FC) (n=50, ρ=0.50, P=1.6 × 10-4). 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 × 10-4) compared with other markers (C-reactive protein (CRP): OR 8.52 (95% CI: 2.75-28.63), P=2.80 × 10-4); 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. CONCLUSIONS: 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.

Risk stratification in acute upper GI bleeding: comparison of the AIMS65 score with the Glasgow-Blatchford and Rockall scoring systems.

BACKGROUND AND AIMS: The American College of Gastroenterology recommends early risk stratification in patients presenting with upper GI bleeding (UGIB). The AIMS65 score is a risk stratification score previously validated to predict inpatient mortality. The aim of this study was to validate the AIMS65 score as a predictor of inpatient mortality in patients with acute UGIB and to compare it with established pre- and postendoscopy risk scores. METHODS: ICD-10 (International Classification of Diseases, Tenth Revision) codes identified patients presenting with UGIB requiring endoscopy. All patients were risk stratified by using the AIMS65, Glasgow-Blatchford score (GBS), pre-endoscopy Rockall, and full Rockall scores. The primary outcome was inpatient mortality. Secondary outcomes were a composite endpoint of inpatient mortality, rebleeding, and endoscopic, radiologic, or surgical intervention; blood transfusion requirement; intensive care unit (ICU) admission; rebleeding; and hospital length of stay. The area under the receiver-operating characteristic curve (AUROC) was calculated for each score. RESULTS: Of the 424 study patients, 18 (4.2%) died and 69 (16%) achieved the composite endpoint. The AIMS65 score was superior to both the GBS (AUROC, 0.80 vs 0.76, P < .027) and the pre-endoscopy Rockall score (0.74, P = .001) and equivalent to the full Rockall score (0.78, P = .18) in predicting inpatient mortality. The AIMS65 score was superior to all other scores in predicting the need for ICU admission and length of hospital stay. AIMS65, GBS, and full Rockall scores were equivalent (AUROCs, 0.63 vs 0.62 vs 0.63, respectively) and superior to pre-endoscopy Rockall (AUROC, 0.55) in predicting the composite endpoint. GBS was superior to all other scores for predicting blood transfusion. CONCLUSION: The AIMS65 score is a simple risk stratification score for UGIB with accuracy superior to that of GBS and pre-endoscopy Rockall scores in predicting in-hospital mortality and the need for ICU admission.

Suspected acute hemolytic transfusion reaction mediated by anti-Di(a).

Anti-Di(a) can mediate hemolytic disease of the fetus and newborn, but it is unclear if it can cause hemolytic transfusion reactions (HTRs). To date, there has only been one report of a possible immediate HTR attributed to anti-Di(a). Our case report details an immediate HTR due to anti-Di(a) in a patient with pre-existing liver failure. This reaction triggered multi-organ failure, and the patient subsequently died. This case also highlights the importance of considering HTRs even when routine antibody screening has been unremarkable, particularly when electronic crossmatch is used, because of the potential for an alloantibody against a low-prevalence antigen.

Bacillus Subtilis (BG01-4TM) Improves Self-Reported Symptoms for Constipation, Indigestion, and Dyspepsia: A Phase 1/2A Randomized Controlled Trial.

BACKGROUND: Functional gastrointestinal disorders (FGIDs) are common, difficult-to-manage conditions. Probiotics are emerging as a dietary component that influence gastrointestinal (GI) health. We conducted a double-blinded randomised controlled trial of a proprietary strain of deactivated Bacillus subtilis (BG01-4™) high in branched-chain fatty acids (BCFA) to treat self-reported FGID. METHODS: Participants (n = 67) completed a four-week intervention of BG01-4™ (n = 34) or placebo (n = 33). The Gastrointestinal Symptom Rating Scale (GSRS) served as the outcome measure, collected prior to, at two weeks, and at four weeks after completion of the intervention. RESULTS: At four weeks, one of three primary outcomes, constipation in the experimental group, was improved by 33% compared to placebo (15%); both other primary outcomes, Total GSRS and diarrhoea, were significantly improved in both the experimental and placebo groups (32%/26% and 20%/22%, respectively). The pre-planned secondary outcome, indigestion, was improved at four weeks (32%) but compared to the placebo (21%) was not significant (p = 0.079). Exploratory analysis, however, revealed that clusters for constipation (18% improvement, p < 0.001), indigestion (11% improvement, p = 0.04), and dyspepsia (10% improvement, p = 0.04) were significantly improved in the intervention group compared to the placebo. CONCLUSIONS: These initial findings suggest that in people with self-reported FGID, BG01-4™ improves specific symptoms of constipation and related GI dysfunction. Longer-term confirmatory studies for this intervention are warranted. TRIAL REGISTRATION: This study was registered prospectively (25 October 2021) at the Australian New Zealand Clinical Trials Registry (ACTRN12621001441808p).

Prevalence of NUDT15 Genetic Variants and Incidence of Thiopurine-induced Leukopenia in Inflammatory Bowel Disease: A Systematic Review and Meta-analysis.

BACKGROUND AND AIMS: Nudix hydrolase 15 [NUDT15] genetic variants confer an increased risk of thiopurine-induced leukopenia [TIL]; however, their global prevalence in inflammatory bowel disease [IBD] patients is unknown. We aimed to evaluate the global prevalence of NUDT15 variants in IBD patients and incidence of TIL in these patients. METHODS: Six databases were searched from inception until July 2022. Studies reporting the frequency of any NUDT15 variant and/or frequency of leukopenia in adult IBD patients with these variants were included. A random effects model was performed to estimate the pooled prevalence of variants, incidence of early [≤8 weeks] and late [>8 weeks] leukopenia, and relative risk of developing leukopenia. RESULTS: Twenty studies comprising 5232 patients were included. The pooled prevalence of the *1/*3 c.415C > T C/T diplotype was 13% (95% confidence interval [CI]: 10-18%), *3/*3 c.415C > T T/T diplotype was 2% [95% CI: 1-2%], *1/*5 c.52G > A G/A diplotype was 2% [95% CI: 1-3%], and *1/*6 c.36_37insGGAGTC ins/- diplotype was 7% [95% CI: 4-12%]. The pooled prevalence of *1/*3 was high in Japanese [20%, 95% CI: 16-24%] and Chinese patients [18%, 95% CI: 12-27%]. The incidence of early leukopenia was 20% [95% CI: 16-26%] in *1/*3 patients, 99% [95% CI: 7-100%] in *3/*3 patients, and 49% [95% CI: 29-69%] in *1/*6 patients. The incidence of late leukopenia was 36% [95% CI: 26-49%] in *1/*3 patients. CONCLUSIONS: NUDT15 variants are common and strongly predict TIL in IBD patients. Pre-treatment NUDT15 genotyping should be considered particularly in Asian populations, to guide thiopurine dosing and prevent myelotoxicity.

Risk of COVID 19 in patients with inflammatory bowel diseases compared to a control population.

BACKGROUND: It is unclear whether patients with inflammatory bowel disease (IBD) are at increased risk of COVID-19. OBJECTIVES: This observational study compared the prevalence of COVID-19 symptoms, diagnosis and hospitalization in IBD patients with a control population with non-inflammatory bowel disorders. METHODS: This multicentre study, included 2733 outpatients (1397 IBD patients and 1336 controls), from eight major gastrointestinal centres in Lombardy, Italy. Patients were invited to complete a web-based questionnaire regarding demographic, historical and clinical features over the previous 6 weeks. The prevalence of COVID-19 symptoms, diagnosis and hospitalization for COVID-19 was assessed. RESULTS: 1810 patients (64%) responded to the questionnaire (941 IBD patients and 869 controls). IBD patients were significantly younger and of male sex than controls. NSAID use and smoking were more frequent in controls. IBD patients were more likely treated with vitamin-D and vaccinated for influenza. Highly probable COVID-19 on the basis of symptoms and signs was less frequent in the IBD group (3.8% vs 6.3%; OR:0.45, 95%CI:0.28-0.75). IBD patients had a lower rate of nasopharyngeal swab-PCR confirmed diagnosis (0.2% vs 1.2%; OR:0.14, 95%CI:0.03-0.67). There was no difference in hospitalization between the groups (0.1% vs 0.6%; OR:0.14, 95%CI:0.02-1.17). CONCLUSION: IBD patients do not have an increased risk of COVID-19 specific symptoms or more severe disease compared with a control group of gastroenterology patients.

Precision medicine in inflammatory bowel disease: concept, progress and challenges.

Crohn's disease and ulcerative colitis are increasingly prevalent, relapsing and remitting inflammatory bowel diseases (IBDs) with variable disease courses and complications. Their aetiology remains unclear but current evidence shows an increasingly complex pathophysiology broadly centring on the genome, exposome, microbiome and immunome. Our increased understanding of disease pathogenesis is providing an ever-expanding arsenal of therapeutic options, but these can be expensive and patients can lose response or never respond to certain therapies. Therefore, there is now a growing need to personalise therapies on the basis of the underlying disease biology and a desire to shift our approach from "reactive" management driven by disease complications to "proactive" care with an aim to prevent disease sequelae. Precision medicine is the tailoring of medical treatment to the individual patient, encompassing a multitude of data-driven (and multi-omic) approaches to foster accurate clinical decision-making. In IBD, precision medicine would have significant benefits, enabling timely therapy that is both effective and appropriate for the individual. In this review, we summarise some of the key areas of progress towards precision medicine, including predicting disease susceptibility and its course, personalising therapies in IBD and monitoring response to therapy. We also highlight some of the challenges to be overcome in order to deliver this approach.

Controversies in Inflammatory Bowel Disease: Exploring Clinical Dilemmas Using Cochrane Reviews.

A symposium organized by the Cochrane IBD Group and presented at the 2017 Digestive Disease Week annual meeting reviewed the recent literature on several controversial topics in inflammatory bowel disease (IBD) management including the efficacy of oral aminosalicylates for induction and maintenance of Crohn's disease (CD), the feasibility of drug withdrawal in patients with quiescent CD, and strategies for detecting colon cancer in patients with IBD. This article summarizes the data presented at that session.

Mitochondrial DNA Is a Pro-Inflammatory Damage-Associated Molecular Pattern Released During Active IBD.

Background: Due to common evolutionary origins, mitochondrial DNA (mtDNA) shares many similarities with immunogenic bacterial DNA. MtDNA is recognized as a pro-inflammatory damage-associated molecular pattern (DAMP) with a pathogenic role in several inflammatory diseases. We hypothesised that mtDNA is released during active disease, serving as a key pro-inflammatory factor in inflammatory bowel disease (IBD). Methods: Between 2014 and 2015, we collected plasma separated within 2 hours of sampling from 97 prospectively recruited IBD patients (67 ulcerative colitis [UC] and 30 Crohn's disease [CD]) and 40 non-IBD controls. We measured circulating mtDNA using quantitative polymerase chain reaction (amplifying mitochondria COXIII/ND2 genes) and also in mouse colitis induced by dextran sulfate-sodium (DSS). We used a mass spectometry approach to detect free plasma mitochondrial formylated peptides. Furthermore, we examined for mitochondrial damage using electron microscopy (EM) and TLR9 expression, the target for mtDNA, in human intestinal IBD mucosa. Results: Plasma mtDNA levels were increased in UC and CD (both P < 0.0001) compared with non-IBD controls. These levels were significantly correlated to blood (C-reactive protein, albumin, white cell count), clinical and endoscopic markers of severity, and disease activity. In active UC, we identified 5 mitochondrial formylated peptides (the most abundant being fMMYALF with known chemoattractant function) in plasma. We observed mitochondrial damage in inflamed UC mucosa and significantly higher fecal MtDNA levels (vs non-IBD controls [P < 0.0001]), which supports gut mucosal mitochondrial DAMP release as the primary source. In parallel, plasma mtDNA levels increased during induction of acute DSS colitis and were associated with more severe colitis (P < 0.05). In active IBD, TLR9+ lamina propria inflammatory cells were significantly higher in UC and CD compared with controls (P < 0.05). Conclusions: We present the first evidence to show that mtDNA is released during active IBD. MtDNA is a potential mechanistic biomarker, and our data point to mtDNA-TLR9 as a therapeutic target in IBD. 10.1093/ibd/izy095_videoizy095.video5776747659001.