Antibiotic therapy in inflammatory bowel disease: a systematic review and meta-analysis

British Society of Gastroenterology consensus guidelines on the management of inflammatory bowel disease in adults

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.

British Society of Gastroenterology consensus guidelines on the management of inflammatory bowel disease in adults

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.

Strategies for developing pregnane X receptor antagonists: Implications from metabolism to cancer

Pregnane X receptor (PXR) is a ligand-activated nuclear receptor (NR) that was originally identified as a master regulator of xenobiotic detoxification. It regulates the expression of drug-metabolizing enzymes and transporters to control the degradation and excretion of endobiotics and xenobiotics, including therapeutic agents. The metabolism and disposition of drugs might compromise their efficacy and possibly cause drug toxicity and/or drug resistance. Because many drugs can promiscuously bind and activate PXR, PXR antagonists might have therapeutic value in preventing and overcoming drug-induced PXR-mediated drug toxicity and drug resistance. Furthermore, PXR is now known to have broader cellular functions, including the regulation of cell proliferation, and glucose and lipid metabolism. Thus, PXR might be involved in human diseases such as cancer and metabolic diseases. The importance of PXR antagonists is discussed in the context of the role of PXR in xenobiotic sensing and other disease-related pathways. This review focuses on the development of PXR antagonists, which has been hampered by the promiscuity of PXR ligand binding. However, substantial progress has been made in recent years, suggesting that it is feasible to develop selective PXR antagonists. We discuss the current status, challenges, and strategies in developing selective PXR antagonists. The strategies are based on the molecular mechanisms of antagonism in related NRs that can be applied to the design of PXR antagonists, primarily driven by structural information.

Microbial Signatures and Innate Immune Gene Expression in Lamina Propria Phagocytes of Inflammatory Bowel Disease Patients

BACKGROUND & AIMS

The interaction between intestinal microbiota and the immune system plays a vital role in inflammatory bowel disease (IBD). Although numerous deep-sequencing studies have suggested dysbiosis in IBD, identifying specific bacteria from the stool or mucosa that are responsible for disease susceptibility or severity has remained a challenge. Lamina propria phagocytes ideally are localized to interact with bacteria that are in close proximity to, or have invaded, the tissue. Thus, we examined the microbial populations associated with the lamina propria phagocytes in 20 Crohn's disease and 12 ulcerative colitis patients. Specifically, we aimed to address whether the phagocyte-associated microbiota differed from the mucosa-associated microbiota and whether this varied based on IBD type or the state of inflammation.

METHODS

16S ribosomal RNA gene sequencing and innate immune gene expression profiling was done on CD11b+ lamina propria phagocytes isolated from the biopsies obtained from IBD patients.

RESULTS

Phagocyte-associated microbiota was enriched in bacterial species belonging to phylum Proteobacteria, whereas species belonging to phylum Bacteroidetes were enriched in the mucosal microbiota of IBD patients. Disease type was the most influential factor in driving differences in the microbiota of both the mucosa and the lamina propria phagocytes, irrespective of inflammation state o`r anatomic location. Crohn's disease and ulcerative colitis specimens showed similar patterns of increased inflammatory gene expression in phagocytes isolated from inflamed areas compared with those isolated from uninflamed regions.

CONCLUSIONS

This pilot study shows the feasibility of using lamina propria phagocytes to characterize the microbiota in IBD patients. The approach used in this study can narrow the spectrum of potentially dysbiotic bacterial populations and clinically relevant gene expression signatures in IBD patients.

How to manage IBD in the 'elderly'

As the incidence of inflammatory bowel disease (IBD) rises and the global population ages, the number of older people living with these conditions will inevitably increase. The challenges posed by comorbid conditions, polypharmacy, the unintended consequences of long-term treatment and the real but often underestimated mismatch between chronological and biological ages underpin management. Significantly, there may be differences in disease characteristics, presentation and management of an older patient with IBD, together with other unique challenges. Importantly, clinical trials often exclude older patients, so treatment decisions are frequently pragmatic, extrapolated from a number of sources of evidence and perhaps primarily dictated by concerns around adverse effects. This review aimed to discuss the epidemiology, clinical features and considerations with management in older patients with IBD.

Inflammatory bowel diseases: interrelationships between dietary vitamin D, exposure to UV radiation and the fecal microbiome

Introduction: Environmental factors and an altered fecal microbiome are believed to be central to the pathogenesis of inflammatory bowel diseases (IBD). Vitamin D and ultraviolet radiation (UVR) are environmental factors that are associated by several pathways, including changes to the gastrointestinal microbiome, with the development and course of IBD.Area covered: This review explores the interaction of vitamin D, and UVR, with the intestinal innate and adaptive immune systems, and how they may influence the gut microbiome and the subsequent development, and progression, of IBD.Expert opinion: Vitamin D and UVR both regulate innate and adaptive immunity through a combination of common and independent mechanisms, with the overall effect being the promotion of immune tolerance. Vitamin D, and to a lesser extent UVR, can modify the gastrointestinal microbiome either directly, or through immune-mediated mechanisms and this may explain the effect on intestinal inflammation in animal models of IBD and some clinical studies. Thus, both vitamin D and UVR exposure can be considered potential 'master regulators' of gastrointestinal immunity, fine-tuning the complex interaction between genetics, host immunity and the gut microbiome. Further research and increased understanding of environment-host interactions is essential to achieving the ultimate goal of preventing and curing IBD.

The Functions and Therapeutic Potential of Heat Shock Proteins in Inflammatory Bowel Disease-An Update

Inflammatory bowel disease (IBD) is a multifactorial human intestinal disease that arises from numerous, yet incompletely defined, factors. Two main forms, Crohn's disease (CD) and ulcerative colitis (UC), lead to a chronic pathological form. Heat shock proteins (HSPs) are stress-responsive molecules involved in various pathophysiological processes. Several lines of evidence link the expression of HSPs to the development and prognosis of IBD. HSP90, HSP70 and HSP60 have been reported to contribute to IBD in different aspects. Moreover, induction and/or targeted inhibition of specific HSPs have been suggested to ameliorate the disease consequences. In the present review, we shed the light on the role of HSPs in IBD and their targeting to prevent further disease progression.

Life-long antimicrobial therapy: where is the evidence?

The decision to prescribe long-term or 'life-long' antibiotics in patients requires careful consideration by the treating clinician. While several guidelines exist to help assist in this decision, the long-term consequences are yet to be well studied. In this review, we aim to provide a summary of the available evidence for patient populations where long-term antibiotic therapy is currently recommended in clinical practice. We will also discuss the pitfalls of this approach, including medication adverse effects, economic cost and any possible contribution to the emerging epidemic of microbial resistance.

Sex-related Alterations of Gut Microbiota in the C57BL/6 Mouse Model of Inflammatory Bowel Disease

Background

Gut microbiota is closely associated with development and exacerbation of inflammatory bowel diseases (IBD). The aim of this study was to investigate differences in gut microbiota depending on sex and changes of gut microbiota during IBD developments.

Methods

16s rRNA metagenomic sequencing was performed for fecal materials from 8-week-old wild type (WT) and interleukin 10 (IL-10) knockout (KO) C57BL/6 mice of both sexes. Diversity indices, relative abundance of microbiota, and linear discriminant analysis effect size were examined to compare microbial communities between groups. Clustering of groups was performed by principal coordinates analysis (PCoA) and unweighted pair group method with arithmetic mean (UPGMA). Functional capabilities of microbiota were estimated using phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) based on Kyoto Encyclopedia of Genes and Genomes database.

Results

PCoA and UPGMA tree analysis of beta-diversity demonstrated significant differences in gut microbiota between male and female groups of WT mice, but not of IL-10 KO mice. Firmicutes to Bacteroides ratio was higher in male group than that in female group in both WT mice and IL-10 KO mice. Phylum Proteobacteria significantly increased in female IL-10 KO mice than that in female WT mice. At species level, Lactobacillus murinus, Bacteroides acidifaciens, and Helicobacter hepaticus significantly increased in IL-10 KO mice than in WT mice. The relative abundance of beta-glucuronidase (K01195) was higher in female IL-10 KO mice than that in female WT mice by PICRUSt.

Conclusions

Our results suggest that microbiota-host interactions might differ between sexes during development of IBD.

Efficacy of Combination Antibiotic Therapy for Refractory Pediatric Inflammatory Bowel Disease

BACKGROUND

Recent studies have shown that oral combination antibiotics may improve disease course in refractory inflammatory bowel disease (IBD). Here, we describe the use of combination oral antibiotics as salvage therapy in refractory ulcerative colitis (UC), Crohn's colitis, and IBD-unclassified (IBD-U) at a large pediatric IBD center.

METHODS

Clinical response, disease activity indices, adverse events, and clinical outcomes were measured up to 1 year after antibiotic treatment in this retrospective cohort study of children with medically refractory IBD colitis.

RESULTS

Sixty-three patients with refractory UC, Crohn's colitis, and IBD-U (median age [interquartile range {IQR}], 15.3 [11.2-16.5] years; median disease duration [IQR], 1.2 [0.41-4.6] years) received a combination of 3 or 4 oral antibiotics (most commonly amoxicillin, metronidazole, and either doxycycline or ciprofloxacin) for a median (IQR) of 29 (21-58) days. Thirty-four patients (54%) were deemed corticosteroid-refractory or -dependent, with the majority (62/63) having a previous or present loss of response or primary nonresponse to anti-tumor necrosis factor alpha (anti-TNFα) therapy. Use of combination antibiotics led to a significant decrease in median Pediatric Ulcerative Colitis Activity Index (PUCAI) score (IQR) from 55 (40-65) to 10 (0-40; P < 0.0001) over 3 ± 1 weeks, with 25/63 (39.7%) patients achieving clinical remission (PUCAI <10 points). The clinical benefits of oral antibiotics were independent of anti-TNFα therapy optimization. Among children entering clinical remission (n = 25), only 1 patient required surgery at 1-year follow-up, vs 10 patients in the nonresponder group. Negative predictors of response to combination antibiotics were exposure to doxycycline (odds ratio [OR], 0.25; 95% CI, 0.08-0.76) and PUCAI ≥65 at baseline (OR, 0.2; 95% CI, 0.05-0.74).

CONCLUSIONS

Oral combination antibiotics appears to be an effective rescue and steroid-sparing therapy to induce remission in the short term in patients failing a biologic.

Diet-induced remission in chronic enteropathy is associated with altered microbial community structure and synthesis of secondary bile acids

BACKGROUND

The microbiome has been implicated in the initiation and persistence of inflammatory bowel disease. Despite the fact that diet is one of the most potent modulators of microbiome composition and function and that dietary intervention is the first-line therapy for treating pediatric Crohn's disease, the relationships between diet-induced remission, enteropathy, and microbiome are poorly understood. Here, we leverage a naturally-occurring canine model of chronic inflammatory enteropathy that exhibits robust remission following nutritional therapy, to perform a longitudinal study that integrates clinical monitoring, 16S rRNA gene amplicon sequencing, metagenomic sequencing, metabolomic profiling, and whole genome sequencing to investigate the relationship between therapeutic diet, microbiome, and disease.

RESULTS

We show that remission induced by a hydrolyzed protein diet is accompanied by alterations in microbial community structure marked by decreased abundance of pathobionts (e.g., Escherichia coli and Clostridium perfringens), reduced severity of dysbiosis, and increased levels of the secondary bile acids, lithocholic and deoxycholic acid. Physiologic levels of these bile acids inhibited the growth of E. coli and C. perfringens isolates, in vitro. Metagenomic analysis and whole genome sequencing identified the bile acid producer Clostridium hiranonis as elevated after dietary therapy and a likely source of secondary bile acids during remission. When C. hiranonis was administered to mice, levels of deoxycholic acid were preserved and pathology associated with DSS colitis was ameliorated. Finally, a closely related bile acid producer, Clostridium scindens, was associated with diet-induced remission in human pediatric Crohn's disease.

CONCLUSIONS

These data highlight that remission induced by a hydrolyzed protein diet is associated with improved microbiota structure, an expansion of bile acid-producing clostridia, and increased levels of secondary bile acids. Our observations from clinical studies of exclusive enteral nutrition in human Crohn's disease, along with our in vitro inhibition assays and in vivo studies in mice, suggest that this may be a conserved response to diet therapy with the potential to ameliorate disease. These findings provide insight into diet-induced remission of gastrointestinal disease and could help guide the rational design of more effective therapeutic diets.

A challenge in diagnosis and management of ulcerative colitis in elderly patient with atypical presentation: A reported case

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Diagnosis of severe UC constitutes a difficult task in elderly patient.

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CT imaging can help physicians exclude non-surgical condition.

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Severe UC should be kept in mind in elderly patients with new onset abdominal pain.

Introduction

Recognition of elderly-onset ulcerative colitis (UC) remains poor as the differential diagnosis in older patients with acute abdominal pain and bloody diarrhea is extensive and UC is generally not the obvious cause. A typical presentation in an elderly patient with acute severe UC can mimic surgical abdomen.

Presentation of case

An 80-year-old female had been presented with high grade fever, abdominal pain and diarrhoea. Physical examination showed sign of peritonitis and severe hypotension. A provisional diagnosis of perforated sigmoid diverticulitis was made. However, at the theater, there was only turbid yellowish ascites at cal-de-sac. Consequently, colonoscopy was performed and revealed continuous and circumferential erythematous with friable mucosa and multiple shallow ulcer along upper left side colon. Histologic examination of the colonic tissue was consistent with UC.

Discussion

As UC is uncommon in Thailand and clinical features of elderly-onset UC are much more non-specific; as a result, misdiagnosis at initial presentation is more common in elderly patients (60%) than that in younger population (15%). These might result in an unnecessary exploratory laparotomy; however, computed tomography scan can reduce the risk of that event.

Conclusion

The diagnosis of severe acute UC in elderly patients with acute abdomen had been complicated by the distinctive physiology of this aged group with atypical presentation and markedly unreliable physical examination. Eventually, severe UC should always be kept in mind with a circumstance of abdominal pain in geriatric population.

The evolution of the use of faecal microbiota transplantation and emerging therapeutic indications

Developments in high-throughput microbial genomic sequencing and other systems biology techniques have given novel insight into the potential contribution of the gut microbiota to health and disease. As a result, an increasing number of diseases have been characterised by distinctive changes in the composition and functionality of the gut microbiota; however, whether such changes are cause, consequence, or incidental to the disease in question remains largely uncertain. Restoration of the gut microbiota to a premorbid state is a key novel therapeutic approach of interest, and faecal microbiota transplantation-the transfer of prescreened stool from healthy donors into the gastrointestinal tract of patients-is gaining increasing importance in both the clinical and research settings. At present, faecal microbiota transplantation is only recommended in the treatment of recurrent Clostridioides difficile infection, although a large number of trials are ongoing worldwide exploring other potential therapeutic indications.

Canadian Association of Gastroenterology Clinical Practice Guideline for the Medical Management of Pediatric Luminal Crohn's Disease

BACKGROUND & AIMS

We aim to provide guidance for medical treatment of luminal Crohn's disease in children.

METHODS

We performed a systematic search of publication databases to identify studies of medical management of pediatric Crohn's disease. Quality of evidence and strength of recommendations were rated according to the GRADE (Grading of Recommendation Assessment, Development, and Evaluation) approach. We developed statements through an iterative online platform and then finalized and voted on them.

RESULTS

The consensus includes 25 statements focused on medical treatment options. Consensus was not reached, and no recommendations were made, for 14 additional statements, largely due to lack of evidence. The group suggested corticosteroid therapies (including budesonide for mild to moderate disease). The group suggested exclusive enteral nutrition for induction therapy and biologic tumor necrosis factor antagonists for induction and maintenance therapy at diagnosis or at early stages of severe disease, and for patients failed by steroid and immunosuppressant induction therapies. The group recommended against the use of oral 5-aminosalicylate for induction or maintenance therapy in patients with moderate disease, and recommended against thiopurines for induction therapy, corticosteroids for maintenance therapy, and cannabis in any role. The group was unable to clearly define the role of concomitant immunosuppressants during initiation therapy with a biologic agent, although thiopurine combinations are not recommended for male patients. No consensus was reached on the role of aminosalicylates in treatment of patients with mild disease, antibiotics or vedolizumab for induction or maintenance therapy, or methotrexate for induction therapy. Patients in clinical remission who are receiving immunomodulators should be assessed for mucosal healing within 1 year of treatment initiation.

CONCLUSIONS

Evidence-based medical treatment of Crohn's disease in children is recommended, with thorough ongoing assessments to define treatment success.

Canadian Association of Gastroenterology Clinical Practice Guideline for the Medical Management of Pediatric Luminal Crohn's Disease

BACKGROUND & AIMS

We aim to provide guidance for medical treatment of luminal Crohn's disease in children.

METHODS

We performed a systematic search of publication databases to identify studies of medical management of pediatric Crohn's disease. Quality of evidence and strength of recommendations were rated according to the GRADE (Grading of Recommendation Assessment, Development, and Evaluation) approach. We developed statements through an iterative online platform and then finalized and voted on them.

RESULTS

The consensus includes 25 statements focused on medical treatment options. Consensus was not reached, and no recommendations were made, for 14 additional statements, largely due to lack of evidence. The group suggested corticosteroid therapies (including budesonide for mild to moderate disease). The group suggested exclusive enteral nutrition for induction therapy and biologic tumor necrosis factor antagonists for induction and maintenance therapy at diagnosis or at early stages of severe disease, and for patients failed by steroid and immunosuppressant induction therapies. The group recommended against the use of oral 5-aminosalicylate for induction or maintenance therapy in patients with moderate disease, and recommended against thiopurines for induction therapy, corticosteroids for maintenance therapy, and cannabis in any role. The group was unable to clearly define the role of concomitant immunosuppressants during initiation therapy with a biologic agent, although thiopurine combinations are not recommended for male patients. No consensus was reached on the role of aminosalicylates in treatment of patients with mild disease, antibiotics or vedolizumab for induction or maintenance therapy, or methotrexate for induction therapy. Patients in clinical remission who are receiving immunomodulators should be assessed for mucosal healing within 1 year of treatment initiation.

CONCLUSIONS

Evidence-based medical treatment of Crohn's disease in children is recommended, with thorough ongoing assessments to define treatment success.

Canadian Association of Gastroenterology Clinical Practice Guideline for the Management of Luminal Crohn's Disease

BACKGROUND & AIMS

Crohn's disease (CD) is a lifelong illness with substantial morbidity, although new therapies and treatment paradigms have been developed. We provide guidance for treatment of ambulatory patients with mild to severe active luminal CD.

METHODS

We performed a systematic review to identify published studies of the management of CD. The quality of evidence and strength of recommendations were rated according to the Grading of Recommendation Assessment, Development and Evaluation (GRADE) approach. Statements were developed through an iterative online platform and then finalized and voted on by a group of specialists.

RESULTS

The consensus includes 41 statements focused on 6 main drug classes: antibiotics, 5-aminosalicylate, corticosteroids, immunosuppressants, biologic therapies, and other therapies. The group suggested against the use of antibiotics or 5-aminosalicylate as induction or maintenance therapies. Corticosteroid therapies (including budesonide) can be used as induction, but not maintenance therapies. Among immunosuppressants, thiopurines should not be used for induction, but can be used for maintenance therapy for selected low-risk patients. Parenteral methotrexate was proposed for induction and maintenance therapy in patients with corticosteroid-dependent CD. Biologic agents, including tumor necrosis factor antagonists, vedolizumab, and ustekinumab, were recommended for patients failed by conventional induction therapies and as maintenance therapy. The consensus group was unable to clearly define the role of concomitant immunosuppressant therapies in initiation of treatment with a biologic agent.

CONCLUSIONS

Optimal management of CD requires careful patient assessment, acknowledgement of patient preferences, evidence-based use of existing therapies, and thorough assessment to define treatment success.

Cecropin A Alleviates Inflammation Through Modulating the Gut Microbiota of C57BL/6 Mice With DSS-Induced IBD

The present study is undertaken to assess the alleviating effects of antimicrobial peptide cecropin A on inflammatory bowel disease (IBD) in C57BL/6 mice and changes in the gut microbiota, compared to an antibiotic gentamicin. Different doses of cecropin A were intraperitoneally injected into C57BL/6 mice for 5 days to determine the safe doses. The injection doses at ≤ 15 mg/kg showed no negative impact on the liver, heart, spleen, and kidney. The severe and moderate IBD mice model was successfully established via supplementation of 4 or 2.5% dextran sulfate sodium (DSS) in drinking water for 5 days. The severe IBD model was used to ensure the optimal therapeutic dose of cecropin A. Survival rate, body weight and disease activity index (DAI) scores were measured. Administration of 15 mg/kg, not 5 mg/kg cecropin A, for 5 days increased survival rate and decreased body weight loss of mice. The moderate IBD model was applied to investigate the mechanisms for cecropin A to alleviate inflammation in comparison to gentamicin. The mice were treated with 15 mg/kg cecropin A or 5 mg/kg gentamicin for 3 days. The levels of cytokines and related proteins in the colon were detected by ELISA and Western blotting. The microbiota in cecum contents were analyzed using 16S rRNA gene sequencing. The results showed that cecropin A and gentamicin relieved body weight loss, DAI, and gut mucosa disruption, while decreasing tumor necrosis factor-α (TNF-α), interlukin-1β (IL-1β), and interlukin-6 (IL-6) induced by DSS. In addition, cecropin A and gentamicin showed different effects on the gut microbiota structure. Both cecropin A and gentamicin decreased DSS-induced enrichment of Bacteroidaceae and Enterobacteriaceae. However, cecropin A showed a selective enrichment of Lactobacillus in contrast to gentamicin, which demonstrated a selective effect on Desulfovibrionaceae and Ruminococcaceae. Cecropin A alleviates IBD through decreasing harmful gut microflora and specifically enhancing beneficial gut microflora. The mechanism of this effect is different from gentamicin.

Mechanism-Based Treatment Strategies for IBD: Cytokines, Cell Adhesion Molecules, JAK Inhibitors, Gut Flora, and More

Background

Although TNF inhibitors revolutionized the therapy of inflammatory bowel disease (IBD), we have been reaching a point where other therapies with different mechanisms of action are necessary. A rising number of elderly IBD patients with contraindications to established therapies and a growing group of patients losing response to anti-TNF therapy compel us to find safer, better-tolerated, and, ideally, personalized treatment options. However, in order to choose the right drug to fit a patient, it is indispensable to understand the pathomechanism involved in IBD.

Summary

The aim of this review is to explain the inflammatory signaling pathways in IBD and how to inhibit them with current and future therapeutic approaches. Next to biologic agents targeting inflammatory cytokines (anti-TNF agents, anti-IL-12/-23 agents, and specific inhibitors of IL-23), biologics blocking leukocyte trafficking to the gut (anti-integrin antibodies) are available nowadays. More recently, small molecules inhibiting the JAK-STAT pathway (JAK inhibitors) or preventing lymphocyte trafficking (sphingosine-1-phosphate modulators) have been approved or are under investigation. Furthermore, modifying the microbiota has potential therapeutic effects on IBD, and autologous hematopoietic or mesenchymal stem cell transplantation may be considered for a highly selected group of IBD patients.

Key Message

Physicians should understand the different mechanisms of action of the potential therapies for IBD to select the right drug for the right patient.

Host-derived fecal microRNAs can indicate gut microbiota healthiness and ability to induce inflammation

Disruption of intestine-microbiota symbiosis can result in chronic gut inflammation. We hypothesize that assessing the initial inflammatory potential of the microbiota in patients is essential and that host-derived miRNAs, which can be found in feces, could fulfill this function. We investigated whether the gut microbiota composition impacts the fecal miRNA profile and thereby indicates its ability to influence intestinal inflammation.

Methods: We used high-throughput qPCR to compare fecal miRNA profile between germ-free and conventional mice. Conventionalization of germfree mice by various colitogenic and non-colitogenic microbiotas (IL10^-/- and TLR5^-/- associated microbiota) was performed.

Results: We identified 12 fecal miRNAs impacted by the presence of a microbiota. Conventionalization of germfree mice by various colitogenic and non-colitogenic microbiotas associated with the development of intestinal inflammation (IL10^-/- and TLR5^-/- associated microbiota) yielded distinctively altered fecal miRNA profiles compared to that of mice receiving a “healthy” microbiota. Correlation analysis revealed the existence of interactions between the 12 abovementioned miRNAs and specific microbiota members.

Conclusion: These results showed that fecal miRNA profile can be differentially and specifically impacted by microbiota composition, and that miRNA could importantly serve as markers of the colitogenic potential of the microbiota. This is particularly relevant to assess individual state of the microbiota in patients with dysbiosis-related disorders, such as IBD and potentially determine their ability to respond to therapeutics.

Genetic Factors and the Intestinal Microbiome Guide Development of Microbe-Based Therapies for Inflammatory Bowel Diseases

The intestinal microbiota is a dynamic community of bacteria, fungi, and viruses that mediates mucosal homeostasis and physiology. Imbalances in the microbiome and aberrant immune responses to gut bacteria can disrupt homeostasis and are associated with inflammatory bowel diseases (IBDs) in humans and colitis in mice. We review genetic variants associated with IBD and their effects on the intestinal microbiome, the immune response, and disease pathogenesis. The intestinal microbiome, which includes microbial antigens, adjuvants, and metabolic products, affects the development and function of the intestinal mucosa, influencing inflammatory responses in the gut. Therefore, strategies to manipulate the microbiome might be used in treatment of IBD. We review microbe-based therapies for IBD and the potential to engineer patients' intestinal microbiota. We discuss how studies of patients with IBD and mouse models have advanced our understanding of the interactions between genetic factors and the gut microbiome, and challenges to the development of microbe-based therapies for IBD.

Validation studies for germ-free Smad3-/- mice as a bio-assay to test the causative role of fecal microbiomes in IBD

While the association between microbiomes and inflammatory bowel disease (IBD) is well known, establishing causal relationships between the two is difficult in humans. Germ-free (GF) mice genetically susceptible to IBD can address this question. Smad3^-/- mice with defective transforming growth factor ß signaling are a model of IBD and colon cancer. They develop IBD upon colonization with Helicobacter under specific pathogen-free conditions, suggesting a role of the microbiome in IBD in this model. Thus, we rederived Smad3^-/- mice GF to determine the potential of using these mice for testing the causative role of microbiomes in IBD. We found that fecal microbiomes from mice with IBD cause more severe gut inflammation in GF Smad3^-/- and wild type mice compared to microbiomes from healthy mice and that Helicobacter induces gut inflammation within the context of other microbiomes but not by itself. Unexpectedly, GF Smad3^+/+ and Smad3^+/- mice given IBD microbiomes develop IBD despite their lack of disease in SPF conditions upon Helicobacter infection. This was not unique to the background strain of our Smad3 model (129); both wild type C57BL/6 and 129 strains developed IBD upon fecal transfer. However, wild type Swiss Webster stock was not susceptible, indicating that the genetic background of recipient mice influences the severity of IBD following fecal transfer. Our data suggest that the microbiome is an independent risk factor contributing to IBD development, and careful characterization of new GF models is needed to understand potential sources of confounding factors influencing microbiome studies in these mice.

Dysregulation of Intestinal Epithelial Cell RIPK Pathways Promotes Chronic Inflammation in the IBD Gut

Crohn's disease (CD) and ulcerative colitis (UC) are common intestinal bowel diseases (IBD) characterized by intestinal epithelial injury including extensive epithelial cell death, mucosal erosion, ulceration, and crypt abscess formation. Several factors including activated signaling pathways, microbial dysbiosis, and immune deregulation contribute to disease progression. Although most research efforts to date have focused on immune cells, it is becoming increasingly clear that intestinal epithelial cells (IEC) are important players in IBD pathogenesis. Aberrant or exacerbated responses to how IEC sense IBD-associated microbes, respond to TNF stimulation, and regenerate and heal the injured mucosa are critical to the integrity of the intestinal barrier. The role of several genes and pathways in which single nucleotide polymorphisms (SNP) showed strong association with IBD has recently been studied in the context of IEC. In patients with IBD, it has been shown that the expression of specific dysregulated genes in IECs plays an important role in TNF-induced cell death and microbial sensing. Among them, the NF-κB pathway and its target gene TNFAIP3 promote TNF-induced and receptor interacting protein kinase (RIPK1)-dependent intestinal epithelial cell death. On the other hand, RIPK2 functions as a key signaling protein in host defense responses induced by activation of the cytosolic microbial sensors nucleotide-binding oligomerization domain-containing proteins 1 and 2 (NOD1 and NOD2). The RIPK2-mediated signaling pathway leads to the activation of NF-κB and MAP kinases that induce autophagy following infection. This article will review these dysregulated RIPK pathways in IEC and their role in promoting chronic inflammation. It will also highlight future research directions and therapeutic approaches involving RIPKs in IBD.

A Distinct Gut Microbiota Exists Within Crohn's Disease-Related Perianal Fistulae

BACKGROUND

Gut bacteria are strongly suspected to play a key role in the pathogenesis of Crohn's disease (CD). Studies have demonstrated alterations in the gut microbiota in this patient population. The purpose of this study was to characterize the gut microbiota of fistulizing perianal CD.

MATERIALS AND METHODS

Stool and fistula samples were obtained from patients undergoing surgery for CD-related anorectal fistulae. Microbial compositions of matched stool and fistula samples were characterized using 16S rRNA gene profiling. The effect of sample type, patient gender, disease classification (Montreal A/B), disease activity (Harvey Bradshaw Index), antibiotic use, and presence of active proctitis on microbial composition was assessed.

RESULTS

Samples were obtained from 18 patients. Bacteroides was the most abundant genera across all samples collected, followed by Streptococcus and Bifidobacterium. Bifidobacterium was present at significantly higher levels in fecal samples than fistula samples, whereas Achromobacter and Corynebacterium were present at significantly higher levels in fistula samples. Antibiotic, but not thiopurine or antitumor necrosis factor medication, exposure affected the gut microbial composition. Patient gender, disease classification, disease activity, and presence of active proctitis did not alter stool or fistula microbiota.

CONCLUSIONS

Our data show that the gut microbiota within CD-related anorectal fistulae is distinct from that in stool samples obtained from the same patients. We also observe a dysbiosis in patients treated with antibiotics compared with those not treated with antibiotics.

A Comprehensive Review of the Diagnosis and Pharmacological Management of Crohn's Disease in the Elderly Population

Crohn's disease (CD) in the elderly is rising in prevalence, which is related to an increase in its incidence and improving life expectancies. There are differences in the presentation, natural history, and treatment of CD between adult-onset patients who progress to older age and patients who are initially diagnosed at an older age. Presentation at an older age may also delay or make diagnosis challenging due to accumulating co-morbidities that mimic inflammatory bowel disease. Differences exist between adult- and older-onset disease, yet many guidelines do not specifically distinguish the management of these two distinct populations. Identifying patients at high risk for progression or aggressive disease is particularly important as elderly patients may respond differently to medical and surgical treatment, and may be at higher risk for adverse effects. Despite newer agents being approved for CD, the data regarding efficacy and safety in the elderly are currently limited. Balancing symptom management with risks of medical and surgical therapy is an ongoing challenge and requires special consideration in these two distinct populations.

Microbiota-nourishing Immunity and Its Relevance for Ulcerative Colitis

An imbalance in our microbiota may contribute to many human diseases, but the mechanistic underpinnings of dysbiosis remain poorly understood. We argue that dysbiosis is secondary to a defect in microbiota-nourishing immunity, a part of our immune system that balances the microbiota to attain colonization resistance against environmental exposure to microorganisms. We discuss this new hypothesis and its implications for ulcerative colitis, an inflammatory bowel disease of the large intestine.

ILC3 function as a double-edged sword in inflammatory bowel diseases

Inflammatory bowel diseases (IBD), composed mainly of Crohn's disease (CD) and ulcerative colitis (UC), are strongly implicated in the development of intestinal inflammation lesions. Its exact etiology and pathogenesis are still undetermined. Recently accumulating evidence supports that group 3 innate lymphoid cells (ILC3) are responsible for gastrointestinal mucosal homeostasis through moderate generation of IL-22, IL-17, and GM-CSF in the physiological state. ILC3 contribute to the progression and aggravation of IBD while both IL-22 and IL-17, along with IFN-γ, are overexpressed by the dysregulation of NCR- ILC3 or NCR+ ILC3 function and the bias of NCR+ ILC3 towards ILC1 as well as regulatory ILC dysfunction in the pathological state. Herein, we feature the group 3 innate lymphoid cells' development, biological function, maintenance of gut homeostasis, mediation of IBD occurrence, and potential application to IBD therapy.

Antibiotics and probiotics in inflammatory bowel disease: when to use them?

Antibiotics and probiotics are often used as adjunctive therapy in inflammatory bowel disease. However, data are limited and randomised controlled trials are too inconsistent to provide generalised recommendations for their use in all patients with ulcerative colitis or Crohn's disease. Antibiotics are best used in the management of infectious complications and fistulas in Crohn's disease and, perhaps, in reducing the intensity of inflammation in luminal disease. Ciprofloxacin, metronidazole and rifaximin have been most widely used and studied. On the other hand, there appears to be a limited role for antibiotics in ulcerative colitis (UC). Probiotics are most effective in pouchitis, and may have a role in the initial therapy and maintenance of remission in mild UC; the probiotic cocktail VSL#3 has been the most widely studied. There is scant evidence of efficacy for probiotics in Crohn's disease.

Escherichia coli Pathobionts Associated with Inflammatory Bowel Disease

Gut bacteria play a key role in initiating and maintaining the inflammatory process in the gut tissues of inflammatory bowel disease (IBD) patients, by supplying antigens or other stimulatory factors that trigger immune cell activation. Changes in the composition of the intestinal microbiota in IBD patients compared to that in healthy controls and a reduced diversity of intestinal microbial species are linked to the pathogenesis of IBD. Adherent invasive Escherichia coli (AIEC) has been linked to Crohn's disease (CD) patients, while diffusely adherent E. coli (DAEC) has been associated with ulcerative colitis (UC). Bacteriological analysis of intestinal biopsy specimens and fecal samples from IBD patients shows an increased number of E. coli strains belonging to the B2 phylogenetic group, which are typically known as extraintestinal pathogenic E. coli (ExPEC). Results from studies of both cell cultures and animal models reveal pathogenic features of these E. coli pathobionts, which may link them to IBD pathogenesis. This suggests that IBD-associated E. coli strains play a facilitative role during IBD flares. In this review, we explain IBD-associated E. coli and its role in IBD pathogenesis.

Epithelial-microbial diplomacy: escalating border tensions drive inflammation in inflammatory bowel disease

Inflammatory bowel diseases (IBD) are chronic conditions of the gastrointestinal tract-the main site of host-microbial interaction in the body. Development of IBD is not due to a single event but rather is a multifactorial process where a patient’s genetic background, behavioral habits, and environmental exposures contribute to disease pathogenesis. IBD patients exhibit alterations to gut bacterial populations “dysbiosis” due to the inflammatory microenvironment, however whether this alteration of the gut microbiota precedes inflammation has not been confirmed. Emerging evidence has highlighted the important role of gut microbes in developing measured immune responses and modulating other host responses such as metabolism. Much of the work on the gut microbiota has been correlative and there is an increasing need to understand the intimate relationship between host and microbe. In this review, we highlight how commensal and pathogenic bacteria interact with host intestinal epithelial cells and explore how altered microenvironments impact these connections.

Induction and maintenance treatment of inflammatory bowel disease: A comprehensive review

Ulcerative colitis (UC) and Crohn's disease (CD) are the two major types of inflammatory bowel disease (IBD). We conducted a comprehensive review of meta-analyses to summarize the reported effectiveness of different drugs for IBD. We performed a literature search and a total of 110 meta-analyses from 66 articles were summarized and re-analyzed (62 in UC and 48 in CD). In summary, 5-ASA was more effective than placebo in both induction and maintenance treatment of UC, but there were conflicting results on the effect of 5-ASA on the induction treatment or relapse of CD. The use of immunomodulatory agents in the induction or maintenance phase of UC and CD using immunomodulators appeared to be more effective than placebo, but the results were impacted by small number of patients, discordant results with the largest study and risk of biases. Anti-TNF-α and anti-integrin therapeutic antibodies in both, induction and maintenance, showed a better efficacy than placebo in a large proportion of patients analyzed. Other agents, such as probiotics, antibiotics, omega-3, were shown to be more effective than placebo, but the same issues arose as stated above with the use of immunomodulatory agents. In conclusion, we performed a comprehensive review of meta-analysis on comparative efficacy of pharmacotherapy used in the management of IBD. Our review will augment our understanding of the treatment of UC and CD by providing a guideline for interpreting the statistically significant findings and discusses the optimal choice for IBD treatment.

The Multifactorial Etiopathogeneses Interplay of Inflammatory Bowel Disease: An Overview

The gastrointestinal system where inflammatory bowel disease occurs is central to the immune system where the innate and the adaptive/acquired immune systems are balanced in interactions with gut microbes under homeostasis conditions. This article overviews the high-throughput research screening on multifactorial interplay between genetic risk factors, the intestinal microbiota, urbanization, modernization, Westernization, the environmental influences and immune responses in the etiopathogenesis of inflammatory bowel disease in humans. Inflammatory bowel disease is an expensive multifactorial debilitating disease that affects thousands new people annually worldwide with no known etiology or cure. The conservative therapeutics focus on the established pathology where the immune dysfunction and gut injury have already happened but do not preclude or delay the progression. Inflammatory bowel disease is evolving globally and has become a global emergence disease. It is largely known to be a disease in industrial-urbanized societies attributed to modernization and Westernized lifestyle associated with environmental factors to genetically susceptible individuals with determined failure to process certain commensal antigens. In the developing nations, increasing incidence and prevalence of inflammatory bowel disease (IBD) has been associated with rapid urbanization, modernization and Westernization of the population. In summary, there are identified multiple associations to host exposures potentiating the landscape risk hazards of inflammatory bowel disease trigger, that include: Western life-style and diet, host genetics, altered innate and/or acquired/adaptive host immune responses, early-life microbiota exposure, change in microbiome symbiotic relationship (dysbiosis/dysbacteriosis), pollution, changing hygiene status, socioeconomic status and several other environmental factors have long-standing effects/influence tolerance. The ongoing multipronged robotic studies on gut microbiota composition disparate patterns between the rural vs. urban locations may help elucidate and better understand the contribution of microbiome disciplines/ecology and evolutionary biology in potentially protecting against the development of inflammatory bowel disease.

Antibiotics for induction and maintenance of remission in Crohn's disease

BACKGROUND

Several antibiotics have been evaluated in Crohn's disease (CD), however randomised controlled trials (RCTs) have produced conflicting results.

OBJECTIVES

To assess the efficacy and safety of antibiotics for induction and maintenance of remission in CD.

SEARCH METHODS

We searched MEDLINE, Embase, CENTRAL, the Cochrane IBD Group Specialized Register and Clinicaltrials.gov database from inception to 28 February 2018. We also searched reference lists and conference proceedings.

SELECTION CRITERIA

RCTs comparing antibiotics to placebo or an active comparator in adult (> 15 years) CD patients were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors screened search results and extracted data. Bias was evaluated using the Cochrane risk of bias tool. The primary outcomes were failure to achieve clinical remission and relapse. Secondary outcomes included clinical response, endoscopic response, endoscopic remission, endoscopic relapse, histologic response, histologic remission, adverse events (AEs), serious AEs, withdrawal due to AEs and quality of life. Remission is commonly defined as a Crohn's disease activity index (CDAI) of < 150. Clinical response is commonly defined as a decrease in CDAI from baseline of 70 or 100 points. Relapse is defined as a CDAI > 150. For studies that enrolled participants with fistulizing CD, response was defined as a 50% reduction in draining fistulas. Remission was defined as complete closure of fistulas. We calculated the risk ratio (RR) and corresponding 95% confidence interval (95% CI) for dichotomous outcomes. We calculated the mean difference (MD) and corresponding 95% CI for continuous outcomes. GRADE was used to assess the certainty of the evidence.

MAIN RESULTS

Thirteen RCTs (N = 1303 participants) were eligible. Two trials were rated as high risk of bias (no blinding). Seven trials were rated as unclear risk of bias and four trials were rated as low risk of bias. Comparisons included ciprofloxacin (500 mg twice daily) versus placebo, rifaximin (800 to 2400 mg daily) versus placebo, metronidazole (400 mg to 500 mg twice daily) versus placebo, clarithromycin (1 g/day) versus placebo, cotrimoxazole (960 mg twice daily) versus placebo, ciprofloxacin (500 mg twice daily) and metronidazole (250 mg four time daily) versus methylprednisolone (0.7 to 1 mg/kg daily), ciprofloxacin (500 mg daily), metronidazole (500 mg daily) and budesonide (9 mg daily) versus placebo with budesonide (9 mg daily), ciprofloxacin (500 mg twice daily) versus mesalazine (2 g twice daily), ciprofloxacin (500 mg twice daily) with adalimumab versus placebo with adalimumab, ciprofloxacin (500 mg twice daily) with infliximab versus placebo with infliximab, clarithromycin (750 mg daily) and antimycobacterial versus placebo, and metronidazole (400 mg twice daily) and cotrimoxazole (960 mg twice daily) versus placebo. We pooled all antibiotics as a class versus placebo and antibiotics with anti-tumour necrosis factor (anti-TNF) versus placebo with anti-TNF.The effect of individual antibiotics on CD was generally uncertain due to imprecision. When we pooled antibiotics as a class, 55% (289/524) of antibiotic participants failed to achieve remission at 6 to 10 weeks compared with 64% (149/231) of placebo participants (RR 0.86, 95% CI 0.76 to 0.98; 7 studies; high certainty evidence). At 10 to 14 weeks, 41% (174/428) of antibiotic participants failed to achieve a clinical response compared to 49% (93/189) of placebo participants (RR 0.77, 95% CI 0.64 to 0.93; 5 studies; moderate certainty evidence). The effect of antibiotics on relapse in uncertain. Forty-five per cent (37/83) of antibiotic participants relapsed at 52 weeks compared to 57% (41/72) of placebo participants (RR 0.87, 95% CI 0.52 to 1.47; 2 studies; low certainty evidence). Relapse of endoscopic remission was not reported in the included studies. Antibiotics do not appear to increase the risk of AEs. Thirty-eight per cent (214/568) of antibiotic participants had at least one adverse event compared to 45% (128/284) of placebo participants (RR 0.87, 95% CI 0.75 to 1.02; 9 studies; high certainty evidence). The effect of antibiotics on serious AEs and withdrawal due to AEs was uncertain. Two per cent (6/377) of antibiotic participants had at least one adverse event compared to 0.7% (1/143) of placebo participants (RR 1.70, 95% CI 0.29 to 10.01; 3 studies; low certainty evidence). Nine per cent (53/569) of antibiotic participants withdrew due to AEs compared to 12% (36/289) of placebo participants (RR 0.86, 95% CI 0.57 to 1.29; 9 studies; low certainty evidence) is uncertain. Common adverse events in the studies included gastrointestinal upset, upper respiratory tract infection, abscess formation and headache, change in taste and paraesthesiaWhen we pooled antibiotics used with anti-TNF, 21% (10/48) of patients on combination therapy failed to achieve a clinical response(50% closure of fistulas) or remission (closure of fistulas) at week 12 compared with 36% (19/52) of placebo and anti-TNF participants (RR 0.57, 95% CI 0.29 to 1.10; 2 studies; low certainty evidence). These studies did not assess the effect of antibiotics and anti-TNF on clinical or endoscopic relapse. Seventy-seven per cent (37/48) of antibiotics and anti-TNF participants had an AE compared to 83% (43/52) of anti-TNF and placebo participants (RR 0.93, 95% CI 0.76 to 1.12; 2 studies, moderate certainty evidence). The effect of antibiotics and anti-TNF on withdrawal due to AEs is uncertain. Six per cent (3/48) of antibiotics and anti-TNF participants withdrew due to an AE compared to 8% (4/52) of anti-TNF and placebo participants (RR 0.82, 95% CI 0.19 to 3.45; 2 studies, low certainty evidence). Common adverse events included nausea, vomiting, upper respiratory tract infections, change in taste, fatigue and headache AUTHORS' CONCLUSIONS: Moderate to high quality evidence suggests that any benefit provided by antibiotics in active CD is likely to be modest and may not be clinically meaningful. High quality evidence suggests that there is no increased risk of adverse events with antibiotics compared to placebo. The effect of antibiotics on the risk of serious adverse events is uncertain. The effect of antibiotics on maintenance of remission in CD is uncertain. Thus, no firm conclusions regarding the efficacy and safety of antibiotics for maintenance of remission in CD can be drawn. More research is needed to determine the efficacy and safety of antibiotics as therapy in CD.

AGA Clinical Practice Update on Functional Gastrointestinal Symptoms in Patients With Inflammatory Bowel Disease: Expert Review

DESCRIPTION

The purpose of this clinical practice update review is to describe key principles in the diagnosis and management of functional gastrointestinal (GI) symptoms in patients with inflammatory bowel disease (IBD).

METHODS

The evidence and best practices summarized in this manuscript are based on relevant scientific publications, systematic reviews, and expert opinion where applicable. Best practice advice 1: A stepwise approach to rule-out ongoing inflammatory activity should be followed in IBD patients with persistent GI symptoms (measurement of fecal calprotectin, endoscopy with biopsy, cross-sectional imaging). Best practice advice 2: In those patients with indeterminate fecal calprotectin levels and mild symptoms, clinicians may consider serial calprotectin monitoring to facilitate anticipatory management. Best practice advice 3: Anatomic abnormalities or structural complications should be considered in patients with obstructive symptoms including abdominal distention, pain, nausea and vomiting, obstipation or constipation. Best practice advice 4: Alternative pathophysiologic mechanisms should be considered and evaluated (small intestinal bacterial overgrowth, bile acid diarrhea, carbohydrate intolerance, chronic pancreatitis) based on predominant symptom patterns. Best practice advice 5: A low FODMAP diet may be offered for management of functional GI symptoms in IBD with careful attention to nutritional adequacy. Best practice advice 6: Psychological therapies (cognitive behavioural therapy, hypnotherapy, mindfulness therapy) should be considered in IBD patients with functional symptoms. Best practice advice 7: Osmotic and stimulant laxative should be offered to IBD patients with chronic constipation. Best practice advice 8: Hypomotility agents or bile-acid sequestrants may be used for chronic diarrhea in quiescent IBD. Best practice advice 9: Antispasmodics, neuropathic-directed agents, and anti-depressants should be used for functional pain in IBD while use of opiates should be avoided. Best practice advice 10: Probiotics may be considered for treatment of functional symptoms in IBD. Best practice advice 11: Pelvic floor therapy should be offered to IBD patients with evidence of an underlying defecatory disorder. Best practice advice 12: Until further evidence is available, fecal microbiota transplant should not be offered for treatment of functional GI symptoms in IBD. Best practice advice 13: Physical exercise should be encourage in IBD patients with functional GI symptoms. Best practice advice 14: Until further evidence is available, complementary and alternative therapies should not be routinely offered for functional symptoms in IBD. This Clinical Practice Update was produced by the AGA Institute.

Effects of Azithromycin on Behavior, Pathologic Signs, and Changes in Cytokines, Chemokines, and Neutrophil Migration in C57BL/6 Mice Exposed to Dextran Sulfate Sodium

Here we characterized the murine dextran sulfate sodium (DSS) model of acute colitis. Specifically, we evaluated azithromycin and metronidazole treatment regimens to assess their effects on animal wellbeing, pathologic changes, barrier function, cytokine and chemokine profiles, and neutrophil migration in colon tissue. Azithromycin treatment significantly reduced the severity of colitis, as assessed through body weight change, water consumption, macroscopic lesions, and animal behaviors (activity level, climbing, and grooming), but did not alter food consumption or feeding behavior. Mucosal barrier function (evaluated by using FITC-labeled dextran) was decreased after DSS exposure; azithromycin did not significantly alter barrier function in mice with colitis, whereas metronidazole exacerbated the colitis-related deficit in barrier function. In addition, metronidazole appeared to exacerbate disease as assessed through water consumption and animal behaviors (overall activity, climbing, grooming, and drinking) but had no effect on weight loss, macroscopic lesions, or eating behavior. Pathologic changes were typical for DSS treatment. Antibiotic treatment resulted in reduced levels of proinflammatory cytokines and chemokines and decreased neutrophil adhesion and emigration in DSS-exposed mice. The results highlight the importance of clinical and behavioral assessments in addition to laboratory evaluation as tools to evaluate animal welfare and therapeutic efficacy in disease models. Data from this study suggest that azithromycin may convey some benefits in the mouse DSS colitis model through modulation of the immune response, including neutrophil migration into tissues, whereas metronidazole may exacerbate colitis.

Azithromycin and metronidazole versus metronidazole-based therapy for the induction of remission in mild to moderate paediatric Crohn's disease : a randomised controlled trial

OBJECTIVE

Crohn's disease (CD) pathogenesis associated with dysbiosis and presence of pathobionts in the lumen, intracellular compartments and epithelial biofilms. Azithromycin is active in all three compartments. Our goal was to evaluate if azithromycin-based therapy can improve response and induce remission compared with metronidazole alone in paediatric CD.

DESIGN

This blinded randomised controlled trial allocated children 5-18 years with 10<Pediatric Crohn's Disease Activity Index (PCDAI)≤40 to azithromycin 7.5 mg/kg, 5 days/week for 4 weeks and 3 days/week for another 4 weeks with metronidazole 20 mg/kg/day (group 1) or metronidazole alone (group 2), daily for 8 weeks. Failures from group 2 were offered azithromycin as open label. The primary end point was response defined by a decrease in PCDAI>12.5 or remission using intention to treat analysis.

RESULTS

73 patients (mean age 13.8±3.1 years) were enrolled, 35 to group 1 and 38 to group 2. Response and remission rates at week 8 were identical 23/35 (66%) in group 1 and 17/38 (45%) and 15/38 (39%) in group 2 (P=0.07 and P=0.025, respectively). The needed to treat for remission was 3.7. Faecal calprotectin declined significantly in group 1 (P=0.003) but not in group 2 (p=0.33), and was lower at week 8 (P=0.052). Additional therapy was required in 6/35(17%) from group 1 versus 16/38(42%) in group 2 (P=0.027) by week 8. Among 12 failures in group 2, open-label azithromycin led to remission in 10/12 (83%).

CONCLUSIONS

The combination of azithromycin and metronidazole failed to improve response but was superior for induction of remission and reduction in calprotectin.

TRIAL REGISTRATION NUMBER

NCT01596894.

Effect of Fecal Microbiota Transplantation on 8-Week Remission in Patients With Ulcerative Colitis: A Randomized Clinical Trial

IMPORTANCE

High-intensity, aerobically prepared fecal microbiota transplantation (FMT) has demonstrated efficacy in treating active ulcerative colitis (UC). FMT protocols involving anaerobic stool processing methods may enhance microbial viability and allow efficacy with a lower treatment intensity.

OBJECTIVE

To assess the efficacy of a short duration of FMT therapy to induce remission in UC using anaerobically prepared stool.

DESIGN, SETTING, AND PARTICIPANTS

A total of 73 adults with mild to moderately active UC were enrolled in a multicenter, randomized, double-blind clinical trial in 3 Australian tertiary referral centers between June 2013 and June 2016, with 12-month follow-up until June 2017.

INTERVENTIONS

Patients were randomized to receive either anaerobically prepared pooled donor FMT (n = 38) or autologous FMT (n = 35) via colonoscopy followed by 2 enemas over 7 days. Open-label therapy was offered to autologous FMT participants at 8 weeks and they were followed up for 12 months.

MAIN OUTCOMES AND MEASURES

The primary outcome was steroid-free remission of UC, defined as a total Mayo score of ≤2 with an endoscopic Mayo score of 1 or less at week 8. Total Mayo score ranges from 0 to 12 (0 = no disease and 12 = most severe disease). Steroid-free remission of UC was reassessed at 12 months. Secondary clinical outcomes included adverse events.

RESULTS

Among 73 patients who were randomized (mean age, 39 years; women, 33 [45%]), 69 (95%) completed the trial. The primary outcome was achieved in 12 of the 38 participants (32%) receiving pooled donor FMT compared with 3 of the 35 (9%) receiving autologous FMT (difference, 23% [95% CI, 4%-42%]; odds ratio, 5.0 [95% CI, 1.2-20.1]; P = .03). Five of the 12 participants (42%) who achieved the primary end point at week 8 following donor FMT maintained remission at 12 months. There were 3 serious adverse events in the donor FMT group and 2 in the autologous FMT group.

CONCLUSIONS AND RELEVANCE

In this preliminary study of adults with mild to moderate UC, 1-week treatment with anaerobically prepared donor FMT compared with autologous FMT resulted in a higher likelihood of remission at 8 weeks. Further research is needed to assess longer-term maintenance of remission and safety.

TRIAL REGISTRATION

anzctr.org.au Identifier: ACTRN12613000236796.

Escherichia coli promotes DSS‑induced murine colitis recovery through activation of the TLR4/NF‑κB signaling pathway

Increasing evidence suggests that intestinal microbiota have critical function in the pathogenesis of inflammatory bowel disease. This present study investigated the effects of Escherichia coli (E. coli) in mice with dextran sulfate sodium (DSS)-induced colitis. Furthermore, Toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) gene expression was measured by reverse transcription-quantitative polymerase chain reaction. In total, two experiments were performed. In the first experiment, four groups were established in BALB/c mice: i) Group A, control (no treatments); ii) group B, DSS-induced colitis; iii) group C, DSS-induced colitis bacteria depleted (BD) mice; and iv) group D, E. coli-treated DSS-induced colitis BD mice. In the second experiment, there were three groups: i) Group A1, control C57BL/6 mice; ii) group B1, E. coli-treated DSS-induced colitis BD C57BL/6 mice; and iii) E. coli-treated DSS-induced colitis BD TLR4^−/− mice. Clinical outcomes, colon and immune histopathology and tissue myeloperoxidase activity were assessed. Mice with DSS-induced colitis that were treated with E. coli exhibited enhanced recovery, with significantly improved clinical and histological scores compared with the DSS only group. The mRNA expression of TLR4 and NF-κB in the E. coli-treated group was also significantly higher. These effects were abolished in TLR4^−/− mice, suggesting that E. coli may have promoted recovery through the TLR4 pathway. The present study indicated that E. coli promoted recovery from DSS-induced colitis in mice, potentially through activation of the TLR4/NF-κB signaling pathway.

Dysbiosis of the Gut Microbiota on the Inflammatory Background due to Lack of Suppressor of Cytokine Signalling-1 in Mice

Background

Both environmental and genetic factors have been implicated in the induction of autoimmune disease. Therefore, it is important to understand the pathophysiological significance of the gut microbiota and host genetic background that contribute to an autoimmune disease such as inflammatory bowel disease (IBD). We have previously reported that mice deficient for suppressor of cytokine signaling-1 (SOCS1), in which SOCS1 expression was restored in T and B cells on an SOCS1^-/- background (SOCS1^-/-Tg mice), developed systemic autoimmune diseases accompanied by spontaneous colitis.

Methods

To investigate whether the proinflammatory genetic background affects the gut microbiota, we used SOCS1^-/-Tg mice as a model of spontaneous chronic colitis. Fecal samples were collected from SOCS1^-/-Tg mice and SOCS1^+/+Tg (control) mice at 1 and 6 months of age, and the fecal bacterial 16S ribosomal RNA genes were sequenced using the Illumina MiSeq platform.

Results

Gut microbial diversity was significantly reduced and the intestinal bacterial community composition changed in SOCS1^-/-Tg mice in comparison with the control mice. Interestingly, the population of Prevotella species, which is known to be elevated in ulcerative colitis and colorectal cancer patients, was significantly increased in SOCS1^-/-Tg mice regardless of age.

Conclusion

Taken together, these results suggest that the proinflammatory genetic background owing to SOCS1 deficiency causes dysbiosis of the gut microbiota, which in turn generates a procolitogenic environment.

Antibiotics in inflammatory bowel diseases: do we know what we're doing?

Despite the revolution in inflammatory bowel disease (IBD) treatment over the past two decades with the advent of biological therapies, there remains a substantial proportion of patients with inadequate or unsustained response to existent therapies. The overwhelming focus of IBD therapeutics has been targeting mucosal immunity, however with the developing evidence base pointing to the role of gut microbes in the inflammatory process, renewed focus should be placed on the impact of manipulating the microbiome in IBD management. This review provides an overview of the evidence implicating bacteria in the pathogenesis of gut inflammation in IBD and provides an overview of the evidence of antibiotics in IBD treatment. We also suggest a potential role of antibiotics in clinical practice based on available evidence and clinical experience.

The Microbiome in Patients With Inflammatory Diseases

Microbial dysbiosis characterized by alterations in the structure and function of the gut microbiome has long been implicated in the pathogenesis of inflammatory bowel disease (IBD). To date, most human IBD microbiome studies are focused on microbial composition rather than function, however, with the latest technical advancements complemented by the rapidly dropping costs, studies focusing on the functional aspects of microbial dysbiosis are on the rise. Several compelling and complimentary pieces of evidence support the notion that the gut microbiome and their metabolites play an important role in the development of IBD. Data from preclinical studies overwhelmingly support the notion that changes in the gut microbiome causally underlie IBD pathogenesis. Hence, there is considerable interest in modulating the state and function of the gut microbiome to achieve therapeutic benefits. While the causal potential of the gut microbiome remains an active area of current research in the clinical setting, accumulating correlative evidence support the view that microbial dysbiosis parallels increased incidence of IBD. In this review, we intend to provide a brief overview of the current human IBD microbiome findings, describe the cause-effect relationships between the gut microbiome and IBD, and discuss the possibility of using microbiome-based approaches in the diagnosis, therapy, and management of disease. In addition, the potential role of microbiome-based interventions in the treatment of human IBD is also discussed.

Clinical Practice Guideline for the Medical Management of Perianal Fistulizing Crohn's Disease: The Toronto Consensus

BACKGROUND

Fistulas occur in about 25% of patients with Crohn's disease (CD) and can be difficult to treat. The aim of this consensus was to provide guidance for the management of patients with perianal fistulizing CD.

METHODS

A systematic literature search identified studies on the management of fistulizing CD. The quality of evidence and strength of recommendations were rated according to the Grading of Recommendation Assessment, Development and Evaluation (GRADE) approach. Statements were developed through an iterative online platform using a modified Delphi process, then finalized, and voted on by a group of specialists.

RESULTS

The quality of evidence for treatment of fistulizing CD was generally of very low quality, and because of the scarcity of good randomized controlled trials (RCTs), these consensus statements generally provide conditional suggestions (5 of 7 statements). Imaging and surgical consultations were recommended in the initial assessment of patients with active fistulizing CD, particularly those with complicated disease. Antibiotic therapy is useful for initial symptom control. Antitumor necrosis factor (anti-TNF) therapy was recommended to induce symptomatic response, and continued use was suggested to achieve and maintain complete remission. The use of concomitant immunosuppressant therapies may be useful to optimize pharmacokinetic parameters when initiating anti-TNF therapy. When there has been an inadequate symptomatic response to medical management strategies, surgical therapy may provide effective fistula healing for some patients.

CONCLUSIONS

Optimal management of perianal fistulizing CD requires a collaborative effort between gastroenterologists and surgeons and may include the evidence-based use of existing therapies, as well as surgical assessments and interventions when needed. 10.1093/ibd/izy247_video1izy247.video15978518763001.

Stress Triggers Flare of Inflammatory Bowel Disease in Children and Adults

Inflammatory bowel disease (IBD) is an idiopathic inflammatory disease characterized by chronic and relapsing manifestations. It is noteworthy that the prevalence of IBD is gradually increasing in both children and adults. Currently, the pathogenesis of IBD remains to be completely elucidated. IBD is believed to occur through interactions among genetics, environmental factors, and the gut microbiota. However, the relapsing and remitting course of IBD underlines the importance of other modifiers, such as psychological stress. Growing evidence from clinical and experimental studies suggests that stress acts as a promoting or relapsing factor for IBD. Importantly, recent studies have reported an increasing incidence of anxiety or depression in both children and adults with IBD. In this article, we review the mechanisms by which stress affects IBD, such as via impaired intestinal barrier function, disturbance of the gut microbiota, intestinal dysmotility, and immune and neuroendocrine dysfunction. With regard to both children and adults, we provide recent evidence to describe how stress can affect IBD at various stages. Furthermore, we emphasize the importance of mental healing and discuss the value of approaches targeting stress in clinical management to develop enhanced strategies for the prevention and treatment of IBD.

Colonocyte metabolism shapes the gut microbiota

An imbalance in the colonic microbiota might underlie many human diseases, but the mechanisms that maintain homeostasis remain elusive. Recent insights suggest that colonocyte metabolism functions as a control switch, mediating a shift between homeostatic and dysbiotic communities. During homeostasis, colonocyte metabolism is directed toward oxidative phosphorylation, resulting in high epithelial oxygen consumption. The consequent epithelial hypoxia helps to maintain a microbial community dominated by obligate anaerobic bacteria, which provide benefit by converting fiber into fermentation products absorbed by the host. Conditions that alter the metabolism of the colonic epithelium increase epithelial oxygenation, thereby driving an expansion of facultative anaerobic bacteria, a hallmark of dysbiosis in the colon. Enteric pathogens subvert colonocyte metabolism to escape niche protection conferred by the gut microbiota. The reverse strategy, a metabolic reprogramming to restore colonocyte hypoxia, represents a promising new therapeutic approach for rebalancing the colonic microbiota in a broad spectrum of human diseases.

Pharmacological Approach to the Management of Crohn's Disease Patients with Perianal Disease

Perianal localization of Crohn's disease involves significant morbidity, affects quality of life and results in an increased use of healthcare resources. Medical and surgical therapies contribute to its management. The objective of this review is to address the current understanding in the management of perianal Crohn's disease, with the main focus in reviewing pharmacological therapies, including stem cells. In complex fistulas, once local sepsis has been controlled by surgical drainage and/or antibiotics, anti-TNF drugs (infliximab, adalimumab) are the first-line therapy, with or without associated immunomodulators. Combining surgery and anti-TNF therapy has additional benefits for healing. However, response is inadequate in up to half of cases. A possible role of new biological drugs in this context (vedolizumab, ustekinumab) is an area of ongoing investigation, as is the local application of autologous or allogeneic mesenchymal stem cells. These are non-hematopoietic multipotent cells with anti-inflammatory and immunomodulatory properties, the use of which may successfully treat refractory patients, and seem to be a promising and safe alternative to achieving fistula healing in Crohn's disease, without known systemic effects.

Development of the Pediatric Gut Microbiome: Impact on Health and Disease

The intestinal microbiota are important in human growth and development. Microbial composition may yield insights into the temporal development of microbial communities and vulnerabilities to disorders of microbial ecology such as recurrent Clostridium difficile infection. Discoveries of key microbiome features of carbohydrate and amino acid metabolism are lending new insights into possible therapies or preventative strategies for inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). In this review, we summarize the current understanding of the development of the pediatric gastrointestinal microbiome, the influence of the microbiome on the developing brain through the gut-brain axis, and the impact of dysbiosis on disease development. Dysbiosis is explored in the context of pediatric allergy and asthma, recurrent C. difficile infection, IBD, IBS, and metabolic disorders. The central premise is that the human intestinal microbiome plays a vital role in health and disease, beginning in the prenatal period and extending throughout childhood.