Microbiome-driven IBS metabotypes influence response to the low FODMAP diet: insights from the faecal volatome.

BACKGROUND: Irritable bowel syndrome (IBS) is a common and debilitating disorder manifesting with abdominal pain and bowel dysfunction. A mainstay of treatment is dietary modification, including restriction of FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols). A greater response to a low FODMAP diet has been reported in those with a distinct IBS microbiome termed IBS-P. We investigated whether this is linked to specific changes in the metabolome in IBS-P. METHODS: Solid phase microextraction gas chromatography-mass spectrometry was used to examine the faecal headspace of 56 IBS cases (each paired with a non-IBS household control) at baseline, and after four-weeks of a low FODMAP diet (39 pairs). 50% cases had the IBS-P microbial subtype, while the others had a microbiome that more resembled healthy controls (termed IBS-H). Clinical response to restriction of FODMAPs was measured with the IBS-symptom severity scale, from which a pain sub score was calculated. FINDINGS: Two distinct metabotypes were identified and mapped onto the microbial subtypes. IBS-P was characterised by a fermentative metabolic profile rich in short chain fatty acids (SCFAs). After FODMAP restriction significant reductions in SCFAs were observed in IBS-P. SCFA levels did not change significantly in the IBS-H group. The magnitude of pain and overall symptom improvement were significantly greater in IBS-P compared to IBS-H (p = 0.016 and p = 0.026, respectively). Using just five metabolites, a biomarker model could predict microbial subtype with accuracy (AUROC 0.797, sensitivity 78.6% (95% CI: 0.78-0.94), specificity 71.4% (95% CI: 0.55-0.88). INTERPRETATION: A metabotype high in SCFAs can be manipulated by restricting fermentable carbohydrate, and is associated with an enhanced clinical response to this dietary restriction. This implies that SCFAs harbour pro-nociceptive potential when produced in a specific IBS niche. By ascertaining metabotype, microbial subtype can be predicted with accuracy. This could allow targeted FODMAP restriction in those seemingly primed to respond best. FUNDING: This research was co-funded by Addenbrooke's Charitable Trust, Cambridge University Hospitals and the Wellcome Sanger Institute, and supported by the NIHR Cambridge Biomedical Research Centre (BRC-1215-20014).

Assessing 'response' to the low-FODMAP diet in irritable bowel syndrome: Should we be reporting harder primary endpoints?

BACKGROUND & AIMS: The low-FODMAP diet (LFD) has become almost synonymous with IBS care, yet the challenges associated with this rigorous therapeutic approach are often underacknowledged. Despite positive outcomes in RCTs, comparator groups frequently exhibit substantial response rates, raising questions about the definition of 'response'. Whilst the assessment of response in drug trials has evolved to utilize the more stringent FDA/EMA primary clinical endpoints, trials of the LFD have not yet followed. The aim of this article is to opine whether the current approach to the measurement of clinical response to the LFD in clinical trials should be reconsidered. METHODS: A comprehensive literature review of LFD clinical trials from the past decade was conducted, focusing on recorded response metrics for primary clinical endpoints. RESULTS: While response definitions vary, the 50-point IBS-SSS delta emerged as the predominant metric. Notably, no trials to date have adopted the more stringent primary clinical endpoints used in drug trials. Other response measures included binary response metrics (such as 'adequate clinical response'), changes in visual analogue scales or stool form/output, reductions in abdominal pain, as well as changes the magnitude of the IBS-SSS delta. Whether these metrics correspond to a clinically meaningful improvement for the patient is less clear, and as such aligning patient-clinician expectations can be challenging. CONCLUSIONS: A paradigm shift in the conceptualization of 'response' coupled with an emphasis on harder clinical endpoints in the context of clinical trials may serve to better justify the trade-off between symptom-improvement and the inherent challenges associated with this burdensome therapeutic approach.

Emerging uses of glucagon-like peptide 1 (GLP-1) receptor agonists following ileal resection: literature review and case examples.

Following ileal resection, the combination of severe bile acid (BA) malabsorption, rapid small bowel transit and unrestricted upper gastrointestinal (GI) secretion results in severe diarrhoea that can prove refractory to pharmacological therapies. While established therapies, including BA sequestrants and antidiarrhoeal drugs seek to ameliorate symptoms, they do not target the underlying pathophysiological mechanisms in this patient group. Their use can also be limited by both intolerance and adverse effects. The novel use of glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) in these patients may allow restoration of the physiological negative feedback mechanisms lost in ileal resection and reduce diarrhoea by prolonging small bowel transit time, limiting upper GI secretions and perhaps by inhibiting hepatic BA synthesis. While recent evidence supports the use of GLP-1 RAs as a safe and effective therapy for bile acid diarrhoea (BAD), it remains uncertain whether those with severe BAD and subsequent short bowel syndrome secondary to extensive ileal resection will benefit. Here, we present three cases of severe diarrhoea secondary to extensive ileal resection in which the use of the GLP-1 RA, liraglutide, was well tolerated and resulted in an objective improvement in diarrhoeal symptoms. We further provide a narrative review of the emerging evidence base supporting the use of GLP therapies in this challenging condition.

Experience and opinions relating to pregnancy in patients with chronic intestinal failure: an international survey.

Introduction: Pregnancy in patients with chronic intestinal failure (CIF) is a relatively rare occurrence but is an important contemporary topic given both the increasing use of home parenteral nutrition (HPN) and the demographics of patients with CIF. Method: An opinion-based survey was produced in a multidisciplinary manner, which was then distributed internationally, via the European Society for Clinical Nutrition and Metabolism network, using a web-based survey tool for healthcare professionals with a specialist interest in the management of CIF. Results: Seventy specialists from 11 countries completed the survey. Fifty-four per cent of the respondents reported some experience of managing pregnancy in patients with CIF. However, 60% stated that they did not feel that it was their role to discuss the topic of pregnancy with their patients, with fewer than 10% stating that they routinely did so. Respondents felt that an individualised approach was required when considering alterations to parenteral support prior to conception, during pregnancy and in the postnatal period. Most respondents also felt there was no increased risk of catheter-related blood stream infections, while catheter-related thrombosis was deemed to be the most significant HPN-related complication for pregnant women. Conclusion: This study reports a variable experience, knowledge and confidence of healthcare professionals when considering pregnancy in patients with CIF. The risk of HPN-related complication was felt to be greater during pregnancy, with an individualised approach being the preferred route for most aspects of care. The findings support the need for an international registry and subsequent consensus guidelines for the management of pregnancy in CIF.

Vitamin D Receptor Antagonist MeTC7 Inhibits PD-L1.

Small-molecule inhibitors of PD-L1 are postulated to control immune evasion in tumors similar to antibodies that target the PD-L1/PD-1 immune checkpoint axis. However, the identity of targetable PD-L1 inducers is required to develop small-molecule PD-L1 inhibitors. In this study, using chromatin immunoprecipitation (ChIP) assay and siRNA, we demonstrate that vitamin D/VDR regulates PD-L1 expression in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) cells. We have examined whether a VDR antagonist, MeTC7, can inhibit PD-L1. To ensure that MeTC7 inhibits VDR/PD-L1 without off-target effects, we examined competitive inhibition of VDR by MeTC7, utilizing ligand-dependent dimerization of VDR-RXR, RXR-RXR, and VDR-coactivators in a mammalian 2-hybrid (M2H) assay. MeTC7 inhibits VDR selectively, suppresses PD-L1 expression sparing PD-L2, and inhibits the cell viability, clonogenicity, and xenograft growth of AML cells. MeTC7 blocks AML/mesenchymal stem cells (MSCs) adhesion and increases the efferocytotic efficiency of THP-1 AML cells. Additionally, utilizing a syngeneic colorectal cancer model in which VDR/PD-L1 co-upregulation occurs in vivo under radiation therapy (RT), MeTC7 inhibits PD-L1 and enhances intra-tumoral CD8+T cells expressing lymphoid activation antigen-CD69. Taken together, MeTC7 is a promising small-molecule inhibitor of PD-L1 with clinical potential.

Disease Recurrence and Long-term Outcomes Following the Development of Intestinal Failure in Crohn's Disease: Over 20 Years of Experience from a National Reference Centre.

BACKGROUND AND AIMS: Intestinal failure [IF] is a recognised complication of Crohn's disease [CD]. The aim of this study was to identify factors predicting the development and recurrence of CD in patients with IF [CD-IF], and their long-term outcomes. METHODS: This was a cohort study of adults with CD-IF admitted to a national UK IF reference centre between 2000 and 2021. Patients were followed from discharge with home parenteral nutrition [HPN] until death or February 28, 2021. RESULTS: In all, 124 patients were included; 47 [37.9%] changed disease location and 55 [44.4%] changed disease behaviour between CD and CD-IF diagnosis, with increased upper gastrointestinal involvement [4.0% vs 22.6% patients], p <0.001. Following IF diagnosis, 29/124 [23.4%] patients commenced CD prophylactic medical therapy; 18 [62.1%] had a history of stricturing or penetrating small bowel disease; and nine [31.0%] had ileocolonic phenotype brought back into continuity. The cumulative incidence of disease recurrence was 2.4% at 1 year, 16.3% at 5 years and 27.2% at 10 years; colon-in-continuity and prophylactic treatment were associated with an increased likelihood of disease recurrence. Catheter-related bloodstream infection [CRBSI] rate was 0.32 episodes/1000 catheter days, with no association between medical therapy and CRBSI rate. CONCLUSIONS: This is the largest series reporting disease behaviour and long-term outcomes in CD-IF and the first describing prophylactic therapy use. The incidence of disease recurrence was low. Immunosuppressive therapy appears to be safe in HPN-dependent patients with no increased risk of CRBSI. The management of CD-IF needs to be tailored to the patient's surgical disease history alongside disease phenotype.

Long-term survival following fungal catheter-related bloodstream infection for patients with intestinal failure receiving home parenteral support.

BACKGROUND: A fungal-related catheter-related bloodstream infection (CRBSI) is less frequent than those induced by bacteria. In the past, a single episode of fungal CRBSI has been used as a marker of home parenteral nutrition (HPN) failure and thus a possible indication for intestinal transplantation. METHODS: Survival outcomes were assessed from a prospectively maintained database of patients initiated on HPN for underlying chronic intestinal failure between 1993 and 2018, with a censoring date of December 31, 2020. Cox regression was performed to assess predictors of mortality with univariable and multivariable analysis. RESULTS: A total of 1008 patients were included in the study, with a total of 1 364 595 catheter days. There were 513 CRBSI events recorded in 262 patients, equating to a CRBSI rate of 0.38/1000 catheter days. A total of 38/262 (14.5%) patients had at least one episode of fungal CRBSI, whereas 216/262 (82.4%) had at least one bacterial but no fungal CRBSI. The median time between HPN initiation and the first CRBSI episode was 20.6 months (95% confidence interval, 16.5-24.1). Episodes of fungal or bacterial CRBSI and the number of CRBSI episodes were not associated with increased mortality. Overall, 15 CRBSI-related deaths were observed in the observation period (0.01 CRBSI deaths/1000 catheter days), two of these were fungal in origin. CONCLUSION: The occurrence of a fungal CRBSI does not increase the risk of death compared with patients who have bacterial CRBSI or those without a CRBSI event.

Treatment adaptations and outcomes of patients experiencing inflammatory bowel disease flares during the early COVID-19 pandemic: the PREPARE-IBD multicentre cohort study.

BACKGROUND: The COVID-19 pandemic offered a unique opportunity to understand inflammatory bowel disease (IBD) management during unexpected disruption. This could help to guide practice overall. AIMS: To compare prescribing behaviour for IBD flares and outcomes during the early pandemic with pre-pandemic findings METHODS: We performed an observational cohort study comprising patients who contacted IBD teams for symptomatic flares between March and June 2020 in 60 National Health Service trusts in the United Kingdom. Data were compared with a pre-pandemic cohort after propensity-matching for age and physician global assessment of disease activity. RESULTS: We included 1864 patients in each of the pandemic and pre-pandemic cohorts. The principal findings were reduced systemic corticosteroid prescription during the pandemic in Crohn's disease (prednisolone: pandemic 26.5% vs. 37.1%; p < 0.001) and ulcerative colitis (UC) (prednisolone: pandemic 33.5% vs. 40.7%, p < 0.001), with increases in poorly bioavailable oral corticosteroids in Crohn's (pandemic 15.6% vs. 6.8%; p < 0.001) and UC (pandemic 11.8% vs. 5.2%; p < 0.001). Ustekinumab (Crohn's and UC) and vedolizumab (UC) treatment also significantly increased. Three-month steroid-free remission in each period was similar in Crohn's (pandemic 28.4% vs. 32.1%; p = 0.17) and UC (pandemic 36.4% vs. 40.2%; p = 0.095). Patients experiencing a flare and suspected COVID-19 were more likely to have moderately-to-severely active disease at 3 months than those with a flare alone. CONCLUSIONS: Despite treatment adaptations during the pandemic, steroid-free outcomes were comparable with pre-pandemic levels, although concurrent flare and suspected COVID-19 caused worse outcomes. These findings have implications for IBD management during future pandemics and for standard practice.

Safety and effectiveness of ustekinumab in elderly Crohn's disease patients.

OBJECTIVE: Anti-tumour necrosis factor (TNF) agents are associated with increased infection risk among elderly IBD patients, but little is known about non anti-TNF biologics in this cohort. We examined the safety and effectiveness of ustekinumab in elderly Crohn's patients. METHODS: This retrospective multi-centre cohort study included Crohn's patients ≥60-years old who commenced ustekinumab. We recorded Harvey-Bradshaw index (HBI), concomitant steroid therapy, treatment persistence and new infections or malignancies. Primary outcome was serious infections requiring hospitalisation. RESULTS: Seventy patients were included, with median age of 68 years. 43 (61.4%) had prior anti-TNF exposure, and 15 (21.4%) vedolizumab. Median treatment duration was 12 months, totalling 84 patient-years. Nine serious infections were reported, incidence 106.7/1000 patient-years. Systemic steroids were associated with increased risk of serious infections [odds ratio (OR) 7.83, 95% confidence interval (CI): 1.44-44.32, P = 0.02]. There were 27 "non-serious" infections; 321.4/1000 patient-years. Charlson co-morbidity index (OR 1.49, 95% CI: 1.05-2.12, P = 0.03) and steroid exposure (OR 44.10, 95% CI: 1.75-1112.10, P = 0.02) increased non-serious infection risk (P &lt; 0.05). Mean HBI improved from 8.13 to 4.64 at 6 months and 4.10 at last follow up (P &lt; 0.0001). 12-month treatment persistence was 55.7% (N = 39); 34 (48.6%) were steroid-free. CONCLUSION: Ustekinumab was safe and effective in a cohort of elderly Crohn's disease patients. Infections were mostly mild, not resulting in therapy discontinuation. Serious infection risk was comparable to previously reported rates with anti-TNF agents. Steroid exposure was associated with an increased serious infection risk.

Management of home parenteral nutrition catheter-related bloodstream infections in hospitals outside of a specialized intestinal failure center.

INTRODUCTION: Catheter-related bloodstream infections (CRBSIs) remain the commonest complication associated with home parenteral nutrition (HPN). Although the management outcomes of CRBSIs have been extensively reported by specialized intestinal failure (IF) centers, there are minimal data reporting CRBSI outcomes for HPN-dependent patients admitted to nonspecialized hospitals. METHOD: This was an observational study from a prospectively maintained database of CRBSIs in HPN-dependent patients managed outside of a specialized IF center. RESULTS: Three hundred and six patients from a total cohort of 1066 HPN-dependent patients suffered from 489 CRBSI events from 2003 to 2021; after 2017, 71 of these events were managed at the patient's local, nonspecialized hospital and the remainder at the specialized IF center. From 2017 to 2021, salvage of the central venous catheter (CVC) with antimicrobial therapy was attempted in 32 out of 71 (45.1%) patients admitted to the nonspecialized hospital, with successful salvage recorded in 23 (71.8%) cases. Notably, CVC salvage was attempted more commonly (77 out of 103 [74.8%]; P = 0.004 vs nonspecialized hospital), with a better salvage success rate (64 out of 77 [83.1%] P = 0.01 vs nonspecialized hospital) in patients who were admitted to the specialized IF center. CONCLUSION: In some instances, CRBSIs can be effectively managed when patients presenting to a nonspecialized hospital; however, overall salvage is more likely to be successful in the specialized setting. Further development of clinical and educational networks between IF centers and patients' local hospitals aimed at standardizing care may lead to improved CRBSI outcomes.

Ambulatory care management of 69 patients with acute severe ulcerative colitis in comparison to 695 inpatients: insights from a multicentre UK cohort study.

INTRODUCTION: Acute severe ulcerative colitis (ASUC) traditionally requires inpatient hospital management for intravenous therapies and/or colectomy. Ambulatory ASUC care has not yet been evaluated in large cohorts. AIMS: We used data from PROTECT, a UK multicentre observational COVID-19 inflammatory bowel disease study, to report the extent, safety and effectiveness of ASUC ambulatory pathways. METHODS: Adults (≥18 years old) meeting Truelove and Witts criteria between 1 January 2019-1 June 2019 and 1 March 2020-30 June 2020 were recruited to PROTECT. We used demographic, disease phenotype, treatment outcomes and 3-month follow-up data. Primary outcome was rate of colectomy during the index ASUC episode. Secondary outcomes included corticosteroid response, time to and rate of rescue or primary induction therapy, response to rescue or primary induction therapy, time to colectomy, mortality, duration of inpatient treatment and hospital readmission and colectomy within 3 months of index flare. We compared outcomes in three cohorts: (1) patients treated entirely in inpatient setting; ambulatory patients subdivided into; (2) patients managed as ambulatory from diagnosis and (3) patients hospitalised and subsequently discharged to ambulatory care for continued intravenous steroids. RESULTS: 37% (22/60) participating hospitals used ambulatory pathways. Of 764 eligible patients, 695 (91%) patients received entirely inpatient care, 15 (2%) patients were managed as ambulatory from diagnosis and 54 (7%) patients were discharged to ambulatory pathways. Aside from younger age in patients treated as ambulatory from diagnosis, no significant differences in disease or patient phenotype were observed. The rate of colectomy (15.0% (104/695) vs 13.3% (2/15) vs 13.0% (7/54), respectively, p=0.96) and secondary outcomes were similar among all three cohorts. Stool culture and flexible sigmoidoscopy were less frequently performed in ambulatory cohorts. Forty per cent of patients treated as ambulatory from diagnosis required subsequent hospital admission. CONCLUSIONS: In a post hoc analysis of one of the largest ASUC cohorts collected to date, we report an emerging UK ambulatory practice which challenges treatment paradigms. However, our analysis remains underpowered to detect key outcome measures and further studies exploring clinical and cost-effectiveness as well as patient and physician acceptability are needed. TRIAL REGISTRATION NUMBER: NCT04411784.

How to manage: acute severe colitis.

Acute severe ulcerative colitis (ASUC) is a medical emergency which is associated with significant morbidity and a mortality rate of 1%. ASUC requires prompt recognition and treatment. Optimal management includes admission to a specialist gastrointestinal unit and joint management with colorectal surgeons. Patients need to be screened for concomitant infections and thromboprophylaxis should be administered to mitigate against the elevated risk of thromboembolism. Corticosteroids are still the preferred initial medical therapy but approximately 30%-40% of patients fail steroid therapy and require rescue medical therapy with either infliximab or cyclosporine. Emergency colectomy is required in a timely manner for patients who fail rescue medical therapy to minimise the risk of adverse post-operative outcomes. We discuss current and emerging evidence in the management of ASUC and outline management approaches for clinicians involved in managing ASUC.

Nutritional considerations in severe primary chronic small intestinal dysmotility.

PURPOSE OF REVIEW: To provide an update on the recent evidence underpinning the approach to nutritional care in patients with severe primary chronic small bowel dysmotility. RECENT FINDINGS: Patients with severe chronic small intestinal dysmotility suffer nutritional and nonnutritional morbidity, both as a result of their underlying polysymptomatic, poorly understood condition and the interventions required. A proportion require artificial nutrition support; however, this is associated with impaired quality of life and associated complications. The approach to nutritional support must therefore engage a multidisciplinary team (MDT) to ensure that decisions to escalate beyond oral nutrition reflect individualised risk-benefit discussions while adopting a holistic approach to symptom management. Since nutritional outcomes are worse in those with the chronic intestinal pseudo-obstruction (CIPO) phenotype, differentiation into CIPO and non-CIPO subgroups, using a pragmatic diagnostic approach rather than invasive/poorly tolerated investigations, can be an important step in achieving nutritional care tailored to the individual. SUMMARY: Malnutrition in patients with severe chronic small intestinal dysmotility is multifactorial. Early engagement of a broad team that includes dietitians, psychologists and pain management experts is crucial to achieving the most beneficial and least harmful patient-centred nutritional care outcomes.

Assessment, endoscopy, and treatment in patients with acute severe ulcerative colitis during the COVID-19 pandemic (PROTECT-ASUC): a multicentre, observational, case-control study.

BACKGROUND: There is a paucity of evidence to support safe and effective management of patients with acute severe ulcerative colitis during the COVID-19 pandemic. We sought to identify alterations to established conventional evidence-based management of acute severe ulcerative colitis during the early COVID-19 pandemic, the effect on outcomes, and any associations with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and severe COVID-19 outcomes. METHODS: The PROTECT-ASUC study was a multicentre, observational, case-control study in 60 acute secondary care hospitals throughout the UK. We included adults (≥18 years) with either ulcerative colitis or inflammatory bowel disease unclassified, who presented with acute severe ulcerative colitis and fulfilled the Truelove and Witts criteria. Cases and controls were identified as either admitted or managed in emergency ambulatory care settings between March 1, 2020, and June 30, 2020 (COVID-19 pandemic period cohort), or between Jan 1, 2019, and June 30, 2019 (historical control cohort), respectively. The primary outcome was the proportion of patients with acute severe ulcerative colitis receiving rescue therapy (including primary induction) or colectomy. The study is registered with ClinicalTrials.gov, NCT04411784. FINDINGS: We included 782 patients (398 in the pandemic period cohort and 384 in the historical control cohort) who met the Truelove and Witts criteria for acute severe ulcerative colitis. The proportion of patients receiving rescue therapy (including primary induction) or surgery was higher during the pandemic period than in the historical period (217 [55%] of 393 patients vs 159 [42%] of 380 patients; p=0·00024) and the time to rescue therapy was shorter in the pandemic cohort than in the historical cohort (p=0·0026). This difference was driven by a greater use of rescue and primary induction therapies with biologicals, ciclosporin, or tofacitinib in the COVID-19 pandemic period cohort than in the historical control period cohort (177 [46%] of 387 patients in the COVID-19 cohort vs 134 [36%] of 373 patients in the historical cohort; p=0·0064). During the pandemic, more patients received ambulatory (outpatient) intravenous steroids (51 [13%] of 385 patients vs 19 [5%] of 360 patients; p=0·00023). Fewer patients received thiopurines (29 [7%] of 398 patients vs 46 [12%] of 384; p=0·029) and 5-aminosalicylic acids (67 [17%] of 398 patients vs 98 [26%] of 384; p=0·0037) during the pandemic than in the historical control period. Colectomy rates were similar between the pandemic and historical control groups (64 [16%] of 389 vs 50 [13%] of 375; p=0·26); however, laparoscopic surgery was less frequently performed during the pandemic period (34 [53%] of 64] vs 38 [76%] of 50; p=0·018). Five (2%) of 253 patients tested positive for SARS-CoV-2 during hospital treatment. Two (2%) of 103 patients re-tested for SARS-CoV-2 during the 3-month follow-up were positive 5 days and 12 days, respectively, after discharge from index admission. Both recovered without serious outcomes. INTERPRETATION: The COVID-19 pandemic altered practice patterns of gastroenterologists and colorectal surgeons in the management of acute severe ulcerative colitis but was associated with similar outcomes to a historical cohort. Despite continued use of high-dose corticosteroids and biologicals, the incidence of COVID-19 within 3 months was low and not associated with adverse COVID-19 outcomes. FUNDING: None.

Infliximab in acute severe colitis: getting the right dose.

Acute severe colitis is a medical emergency and requires prompt treatment with intravenous steroids. Infliximab is typically used as rescue therapy in those who fail to respond to corticosteroids. This article outlines the altered pharmacokinetics of infliximab in acute severe UC and summarised the latest published data surrounding accelerated infliximab dosing.