Ineffectiveness of probiotics in preventing recurrence after curative resection for Crohn's disease: a randomised controlled trial with Lactobacillus GG

Evaluating the Efficacy of Probiotics on Disease Progression, Quality of Life, and Nutritional Status Among Patients with Crohn's Disease: A Multicenter, Randomized, Single-Blinded Controlled Trial

BACKGROUND

There is growing interest in the role of gut microbiota in the pathophysiology of inflammatory bowel diseases (IBDs), including Crohn's disease (CD). Probiotics have been proposed as a potential adjunct therapy for these conditions by altering the intestinal environment, although studies on their effectiveness have yielded mixed results.

AIM

This study aims to evaluate the short-term (2 months) effects of a dietary supplement containing Lactobacilli, Bifidobacteria, and Lactococcus bacillus on disease progression, remission, quality of life, and nutritional intake in Lebanese patients with CD.

METHOD

A multicenter, randomized, single-blind controlled trial was conducted in 2 medical centers in Beirut from 1 April 2024 to 1 August 2024. Recruitment, prescreening, screening, enrollment, and protocol implementation were carried out at both centers. Data were collected from 21 patients with CD, who were randomly assigned to the control group (n = 10) and the intervention group (n = 11). At baseline and after two months, participants underwent clinical assessments, WHOQOL-BREF evaluation, and 24 h dietary recalls. Follow-up visits included surveys on disease progression, quality of life, adherence, and adverse events, along with repeat body composition and anthropometric measurements.

RESULTS

Probiotic supplementation over two months did not significantly alter symptoms, flares, or hospitalizations outcomes between the control and intervention groups. However, the intervention group experienced notable increases in body weight (p = 0.01), BMI (p = 0.01), body fat mass (p = 0.04), and arm muscle circumference (p = 0.01). Nutrient intake patterns differed, with the intervention group showing increased consumption of calcium, riboflavin, and folate compared to controls (p = 0.01, p = 0.04, p = 0.013, respectively). Probiotic supplementation led to significant within-group increases in dietary fiber (p = 0.01), total sugar (p = 0.02), and caffeine (p = 0.01) among the intervention participants. Adverse effects in the intervention group were mild, including nausea (18.2%) and abdominal discomfort (9.1%). QOL improved significantly in the intervention group, particularly in physical (p = 0.03), psychological (p = 0.04), and environmental domains (p = 0.003), while the control group exhibited improvements only in psychological health.

CONCLUSIONS

Overall, the findings suggest that probiotics can enhance body composition, nutrient intake, and certain aspects of QOL among CD patients, despite minimal impact on disease symptoms or dietary patterns.

Efficacy and safety of probiotics in IBD: An overview of systematic reviews and updated meta-analysis of randomized controlled trials

BACKGROUND AND OBJECTIVE

Probiotics show promise in inflammatory bowel disease (IBD), yet knowledge gaps persist. We performed an overview of systematic reviews and an updated metanalysis of randomized controlled trials (RCT) assessing the effect of probiotics on Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

MEDLINE, Web of Science, and the Cochrane Central Register of Controlled Trials were searched up to September 2023. Primary outcomes were clinical remission and recurrence; secondary outcomes included endoscopic response and remission, and adverse events. We calculated odds ratios (OR) using a random-effects model in R. The quality of systematic reviews was assessed using the AMSTAR-2; the trials' risk of bias was evaluated using the Cochrane Collaboration tool. Evidence certainty was rated using the GRADE framework.

RESULTS

Out of 2613 results, 67 studies (22 systematic reviews and 45 RCTs) met the eligibility criteria. In the updated meta-analysis, the OR for clinical remission in UC and CD was 2.00 (95% CI 1.28-3.11) and 1.61 (95% CI 0.21-12.50), respectively. The subgroup analysis suggested that combining 5-ASA and probiotics may be beneficial for inducing remission in mild-to-moderate UC (OR 2.35, 95% CI 1.29-4.28). Probiotics decreased the odds of recurrence in relapsing pouchitis (OR 0.03, 95% CI 0.00-0.25) and trended toward reducing clinical recurrence in inactive UC (OR 0.65, 95% CI 0.42-1.01). No protective effect against recurrence was identified for CD. Multi-strain formulations appear superior in achieving remission and preventing recurrence in UC. The use of probiotics was not associated with better endoscopic outcomes. Adverse events were similar to control. However, the overall certainty of evidence was low.

CONCLUSION

Probiotics, particularly multi-strain formulations, appear efficacious for the induction of clinical remission and the prevention of relapse in UC patients as well as for relapsing pouchitis. Notwithstanding, no significant effect was identified for CD. The favorable safety profile of probiotics was also highlighted.

Probiotics: are they beneficial?

There are wide-ranging probiotic choices in Australasia. We reviewed the efficacy of probiotics for the management of gastrointestinal (GI) conditions in adults and assessed relevance to clinical practice. The benefits of probiotics were inconsistent, with a strong consensus reached for only a few of the indications. As different species/strains and combinations differ in efficacy, results cannot be extrapolated from one to another. This review endorses specific probiotics for limited indications. Efficacy of most marketed probiotic formulations remains unstudied and unproven, warranting further research.

Management of Post-Operative Crohn's Disease: Knowns and Unknowns

Crohn's disease (CD) is a chronic inflammatory disorder of the gastrointestinal tract characterized by relapsing-remission phases. CD often requires surgical intervention during its course, mainly ileo-cecal/ileo-colonic resection. However, surgery in CD is not curative and post-operative recurrence (POR) can happen. The management of CD after surgery presents challenges. Ensuring timely, effective, and safe therapy to prevent POR is essential but difficult, considering that approximately 20-30% of subjects may not experience endoscopic POR and that 40-50% will only exhibit intermediate lesions, which carry a low risk of mid- and long-term clinical and surgical POR. Currently, there are two accepted intervention strategies: early post-operative prophylactic therapy (systematically or based on the patient's risk of recurrence) or starting therapy after confirming endoscopic POR 6-12 months after surgery (endoscopy-driven prophylactic therapy). The risk of overtreatment lies in exposing patients to undesired adverse events, along with the costs associated with medications. Conversely, undertreatment may lead to missed opportunities to prevent bowel damage and the necessity for additional surgery. This article aims to perform a comprehensive review regarding the optimal strategy to reduce the risk of POR in CD patients and the current therapeutic options.

Probiotics for inflammatory bowel disease: Is there sufficient evidence?

Inflammatory bowel disease (IBD) refers to chronic inflammatory disorders of the gut. Ulcerative colitis (UC) and Crohn's disease (CD) are two subtypes of IBD. Evidence suggests that the intestinal microbiota plays a role in the pathogenesis of IBD, so probiotics have garnered a lot of interest as a potential treatment or prevention for IBD. However, clinical evidence of the efficacy of probiotics is still debatable. We performed a literature review. An advanced search considered clinical studies on probiotic for IBD from inception to 2023 in PubMed, Embase, Cochrane Library, and Web of Science. In the treatment of UC with probiotics, only Escherichia coli Nissle 1917 for maintenance treatment of UC in remission, and Bifidobacterium and VSL#3 for induction of remission in patients with mild to moderately active UC have shown strong evidence. Currently, there are no definitive conclusions regarding the effectiveness of probiotics in CD. The mechanism of probiotic treatment for IBD may be related to reducing oxidative stress, repairing the intestinal barrier, regulating intestinal flora balance, and modulating intestinal immune response. Differences in the benefits of probiotics between CD and UC may be attributable to the different lesion extent and immune-mediated pathophysiology. More robust randomized clinical trials are required to validate the efficacy and safety of diverse probiotic strains in IBD.

Results of the Eighth Scientific Workshop of ECCO: Prevention and Treatment of Postoperative Recurrence in Patients With Crohn's Disease Undergoing an Ileocolonic Resection With Ileocolonic Anastomosis

Despite the introduction of biological therapies, an ileocolonic resection is often required in patients with Crohn's disease [CD]. Unfortunately, surgery is not curative, as many patients will develop postoperative recurrence [POR], eventually leading to further bowel damage and a decreased quality of life. The 8th Scientific Workshop of ECCO reviewed the available scientific data on both prevention and treatment of POR in patients with CD undergoing an ileocolonic resection, dealing with conventional and biological therapies, as well as non-medical interventions, including endoscopic and surgical approaches in case of POR. Based on the available data, an algorithm for the postoperative management in daily clinical practice was developed.

The interaction of bile acids and gut inflammation influences the pathogenesis of inflammatory bowel disease

Bile acids (BA) are amphipathic molecules originating from cholesterol in the liver and from microbiota-driven biotransformation in the colon. In the gut, BA play a key role in fat digestion and absorption and act as potent signaling molecules on the nuclear farnesoid X receptor (FXR) and membrane-associated G protein-coupled BA receptor-1 (GPBAR-1). BA are, therefore, involved in the maintenance of gut barrier integrity, gene expression, metabolic homeostasis, and microbiota profile and function. Disturbed BA homeostasis can activate pro-inflammatory pathways in the gut, while inflammatory bowel diseases (IBD) can induce gut dysbiosis and qualitative and/or quantitative changes of the BA pool. These factors contribute to impaired repair capacity of the mucosal barrier, due to chronic inflammation. A better understanding of BA-dependent mechanisms paves the way to innovative therapeutic tools by administering hydrophilic BA and FXR agonists and manipulating gut microbiota with probiotics and prebiotics. We discuss the translational value of pathophysiological and therapeutic evidence linking BA homeostasis to gut inflammation in IBD.

Tumorigenesis in Inflammatory Bowel Disease: Microbiota-Environment Interconnections

Colo-rectal cancer (CRC) is undoubtedly one of the most severe complications of inflammatory bowel diseases (IBD). While sporadic CRC develops from a typical adenoma-carcinoma sequence, IBD-related CRC follows different and less understood pathways and its pathophysiological mechanisms were not completely elucidated. In contrast to chronic inflammation, which is nowadays a well-recognised drive towards neoplastic transformation in IBD, only recently was gut microbiota demonstrated to interfere with both inflammation processes and immune-mediated anticancer surveillance. Moreover, the role of microbiota appears particularly complex and intriguing when also considering its multifaceted interactions with multiple environmental stimuli, notably chronic pathologies such as diabetes and obesity, lifestyle (diet, smoking) and vitamin intake. In this review, we presented a comprehensive overview on current evidence of the influence of gut microbiota on IBD-related CRC, in particular its mutual interconnections with the environment.

ESPEN guideline on Clinical Nutrition in inflammatory bowel disease

The present guideline is an update and extension of the ESPEN scientific guideline on Clinical Nutrition in Inflammatory Bowel Disease published first in 2017. The guideline has been rearranged according to the ESPEN practical guideline on Clinical Nutrition in Inflammatory Bowel Disease published in 2020. All recommendations have been checked and, if needed, revised based on new literature, before they underwent the ESPEN consensus procedure. Moreover, a new chapter on microbiota modulation as a new option in IBD treatment has been added. The number of recommendations has been increased to 71 recommendations in the guideline update. The guideline is aimed at professionals working in clinical practice, either in hospitals or in outpatient medicine, and treating patients with IBD. General aspects of care in patients with IBD, and specific aspects during active disease and in remission are addressed. All recommendations are equipped with evidence grades, consensus rates, short commentaries and links to cited literature.

Lactobacillus plantarum Metabolites Elicit Anticancer Effects by Inhibiting Autophagy-Related Responses

Lactobacillus plantarum (L. plantarum) is a probiotic that has emerged as novel therapeutic agents for managing various diseases, such as cancer, atopic dermatitis, inflammatory bowel disease, and infections. In this study, we investigated the potential mechanisms underlying the anticancer effect of the metabolites of L. plantarum. We cultured L. plantarum cells to obtain their metabolites, created several dilutions, and used these solutions to treat human colonic Caco-2 cells. Our results showed a 10% dilution of L. plantarum metabolites decreased cell viability and reduced the expression of autophagy-related proteins. Moreover, we found co-treatment with L. plantarum metabolites and chloroquine, a known autophagy inhibitor, had a synergistic effect on cytotoxicity and downregulation of autophagy-related protein expression. In conclusion, we showed the metabolites from the probiotic, L. plantarum, work synergistically with chloroquine in killing Caco-2 cells and downregulating the expression of autophagy-related proteins, suggesting the involvement of autophagy, rather than apoptosis, in their cytotoxic effect. Hence, this study provides new insights into new therapeutic methods via inhibiting autophagy.

The Role of Probiotics in Inducing and Maintaining Remission in Crohn's Disease and Ulcerative Colitis: A Systematic Review of the Literature

Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory diseases of the gastrointestinal tract affecting millions of patients worldwide. The gut microbiome partly determines the pathogenesis of both diseases. Even though probiotics have been widely used as a potential treatment, their efficacy in inducing and maintaining remission is still controversial. Our study aims to review the present-day literature about the possible role of probiotics in treating inflammatory bowel diseases in adults. This research was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. We included studies concerning adult patients who compared probiotics with placebo or non-probiotic intervention. We identified thirty-three studies, including 2713 patients from fourteen countries. The role of probiotics in Crohn's disease was examined in eleven studies. Only four studies presented statistically significant results in the remission of disease, primarily when used for three to six months. On the other hand, in twenty-one out of twenty-five studies, probiotics proved effective in achieving or maintaining remission in ulcerative colitis. Supplementation with Bifidobacterium sp. or a combination of probiotics is the most effective intervention, especially when compared with a placebo. There is strong evidence supporting the usage of probiotic supplementation in patients with ulcerative colitis, yet more research is needed to justify their efficacy in Crohn's disease.

The Potential Therapeutic Role of Lactobacillaceae rhamnosus for Treatment of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a heterogeneous group of diseases associated with chronic inflammation of the intestinal tract, and is highly prevalent worldwide. Although its origin is not yet fully understood, new evidence emphasizes that environmental factors, especially dietary factors and intestinal microbiota disorders are key triggers of IBD. Probiotics, such as Lactobacillaceae spp., play an essential role in human health as they exert beneficial effects on the composition of the human gastrointestinal microbial community and immune system. Probiotic-based therapies have been shown to be effective in alleviating IBD. Among these, Lactobacillaceae rhamnosus is one of the most widely used strains. L. rhamnosus is widely present in the intestines of healthy individuals; it regulates the intestinal immune system and reduces inflammation through a variety of mechanisms. The purpose of this study was to identify scientific evidence related to L. rhamnosus and IBD, review and summarize the results, and discuss the possible mechanisms of action as a starting point for future research on IBD treatment.

Factors associated with the prescription of probiotics in patients with inflammatory bowel disease: a cross-sectional study

BACKGRUOUND

Commensal bacteria play an important role in the pathogenesis of inflammatory bowel disease (IBD) and probiotics have been used as treatment options. We aimed to explore the current use of probiotics and factors associated with their prescription in patients with IBD.

METHODS

This cross-sectional study was conducted on a single hospital-based cohort. Patients were eligible if they were ≥18 years old, visited the IBD clinic as an outpatient more than twice during the study period, and had a confirmed diagnosis of IBD. Patients were divided into two groups based on the prescription of probiotics. Clinical assessments were compared between the two groups.

RESULTS

In total, 217 patients were enrolled in this study. In patients with Crohn disease (CD), moderate or severe abdominal pain; prior use of methotrexate (MTX), iron, thiopurines, or biologics; history of IBD-related surgery; and stool frequency were independently associated with the prescription of probiotics. In patients with ulcerative colitis (UC), moderate or severe abdominal pain, hematochezia, stool frequency, and moderate or severe physician global assessment score were independently associated with the prescription of probiotics.

CONCLUSION

Increased disease activity may be associated with fewer prescriptions of probiotics in patients with IBD. However, physicians prescribed probiotics to control symptoms, such as abdominal pain and increased stool frequency in patients with UC and CD, and hematochezia in patients with UC. Additionally, the use of MTX and iron, and a history of IBD-related surgeries were associated with more frequent probiotic prescriptions in patients with CD.

Probiotics (Lactobacillus plantarum HNU082) Supplementation Relieves Ulcerative Colitis by Affecting Intestinal Barrier Functions, Immunity-Related Gene Expression, Gut Microbiota, and Metabolic Pathways in Mice

Probiotics can effectively improve ulcerative colitis (UC), but the mechanism is still unclear. Here, shotgun metagenome and transcriptome analyses were performed to explore the therapeutic effect and the mechanism of the probiotic Lactobacillus plantarum HNU082 (Lp082) on UC. The results showed that Lp082 treatment significantly ameliorated dextran sulfate sodium (DSS)-induced UC in mice, which was manifested as increases in body weight, water intake, food intake, and colon length and decreases in disease activity index (DAI), immune organ index, inflammatory factors, and histopathological scores after Lp082 intake. An in-depth study discovered that Lp082 could improve the intestinal mucosal barrier and relieve inflammation by cooptimizing the biological barrier, chemical barrier, mechanical barrier, and immune barrier. Specifically, Lp082 rebuilt the biological barrier by regulating the intestinal microbiome and increasing the production of short-chain fatty acids (SCFAs). Lp082 improved the chemical barrier by reducing intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule (VCAM) and increasing goblet cells and mucin2. Lp082 ameliorated the mechanical barrier by increasing zonula occludens-1 (ZO-1), zonula occludens-2 (ZO-2), and occludin while decreasing claudin-1 and claudin-2. Lp082 optimized the immune barrier by reducing the content of interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), myeloperoxidase (MPO), and interferon-γ (IFN-γ) and increasing IL-10, transforming growth factor-β1 (TGF-β1), and TGF-β2, inhibiting the NF-κB signaling pathway. Taken together, probiotic Lp082 can play a protective role in a DSS-induced colitis mouse model by protecting the intestinal mucosal barrier, attenuating the inflammatory response, and regulating microbial imbalance. This study provides support for the development of probiotic-based microbial products as an alternative treatment strategy for UC. IMPORTANCE Many studies have focused on the therapeutic effect of probiotics on ulcerative colitis (UC), but few studies have paid attention to the mechanism of probiotics, especially the therapeutic effect. This study suggests that Lp082 has a therapeutic effect on colitis in mice. Its mechanisms of action include protecting the mucosal barrier and actively modulating the gut microbiome, modulating inflammatory pathways, and reducing neutrophil infiltration. Our study enriches the mechanism and provides a new prospect for probiotics in the treatment of colitis, helps to deepen the understanding of the intestinal mucosal barrier, and provides guidance for the future probiotic treatment of human colitis.

Lactobacillus plantarum HNU082 alleviates dextran sulfate sodium-induced ulcerative colitis in mice through regulating gut microbiome

Probiotics have shown good efficacy in the prevention of ulcerative colitis (UC), but the specific mechanism remains unclear. Therefore, shotgun metagenomic and transcriptome analyses were performed to explore the preventive effect of a potential probiotic Lactobacillus plantarum HNU082 (Lp082) on UC and its specific mechanism. The results showed that Lp082 intervention ameliorated dextran sulfate sodium (DSS)-induced UC in mice, which was manifested in the increase in body weight, water intake, food intake, and colon length and the decrease in the DAI index, immune organ index, inflammatory factors and histopathological scores after Lp082 intake. The mechanism is deeply studied and it is discovered that Lp082 improves the intestinal mucosal barrier by co-optimizing biological barriers, chemical barriers, mechanical barriers, and immune barriers. Specifically, Lp082 improved the biological barrier by increasing the diversity, optimizing the species composition and the structure of the gut microbiota, increasing bacteria producing short chain fatty acids (SCFAs), and activating microbial metabolic pathways producing SCFAs so as to enhance the content of SCFAs. Lp082 optimized the chemical barrier by decreasing the mRNA expression of ICAM-1 and VCAM and by increasing the content of goblet cells and the mRNA expression and immunofluorescent protein content of mucin2. Lp082 ameliorated the mechanical barrier by decreasing the mRNA expression of claudin-1 and claudin-2, and by increasing the mRNA expression of ZO-1 and ZO-2 and the immunofluorescent protein content of ZO-1. Lp082 also optimized the immune barrier by increasing the mRNA expression of IL-10, TGF-β1, and TGF-β2 and by decreasing the mRNA expression and protein contents of IL-6, tumour necrosis factor-alpha (TNF-α) and myeloperoxidase (MPO). In addition, Lp082 can also regulate the metabolic pathways of inflammation and disease in mice, and notably, Lp082 inhibits the NF-κB signaling pathway by inhibiting NF-κB signaling molecules to alleviate UC. In conclusion, improving gut microbiota dysbiosis, protecting the intestinal mucosal barrier, regulating inflammatory and disease pathways, and affecting neutrophil infiltration are the potential mechanisms of probiotic Lp082 in alleviating UC. Our study enriches the mechanism and provides a new prospect for Lactobacillus plantarum HNU082 in the prevention of colitis, provides support for the development of probiotic-based microbial products as an alternative prevention strategy for UC, and provides guidance for the future probiotic prevention of human colitis.

The emerging microbiome-based approaches to IBD therapy: From SCFAs to urolithin A

Inflammatory bowel disease (IBD) is a group of chronic gastrointestinal inflammatory conditions which can be life-threatening, affecting both children and adults. Crohn's disease and ulcerative colitis are the two main forms of IBD. The pathogenesis of IBD is complex and involves genetic background, environmental factors, alteration in gut microbiota, aberrant immune responses (innate and adaptive), and their interactions, all of which provide clues to the identification of innovative diagnostic or prognostic biomarkers and the development of novel treatments. Gut microbiota provide significant benefits to its host, most notably via maintaining immunological homeostasis. Furthermore, changes in gut microbial populations may promote immunological dysregulation, resulting in autoimmune diseases, including IBD. Investigating the interaction between gut microbiota and immune system of the host may lead to a better understanding of the pathophysiology of IBD as well as the development of innovative immune- or microbe-based therapeutics. In this review we summarized the most recent findings on innovative therapeutics for IBD, including microbiome-based therapies such as fecal microbiota transplantation, probiotics, live biotherapeutic products, short-chain fatty acids, bile acids, and urolithin A.

Manipulation of Gut Microbiota as a Key Target for Crohn's Disease

Crohn's disease (CD) is an inflammatory bowel disease (IBD) sub-type characterized by transmural chronic inflammation of the gastrointestinal tract. Research indicates a complex CD etiology involving genetic predisposition and immune dysregulation in response to environmental triggers. The chronic mucosal inflammation has been associated with a dysregulated state, or dysbiosis, of the gut microbiome (bacteria), mycobiome (fungi), virome (bacteriophages and viruses), and archeaome (archaea) further affecting the interkingdom syntrophic relationships and host metabolism. Microbiota dysbiosis in CD is largely described by an increase in facultative anaerobic pathobionts at the expense of strict anaerobic Firmicutes, such as Faecalibacterium prausnitzii. In the mycobiome, reduced fungal diversity and fungal-bacteria interactions, along with a significantly increased abundance of Candida spp. and a decrease in Saccharomyces cerevisiae are well documented. Virome analysis also indicates a significant decrease in phage diversity, but an overall increase in phages infecting bacterial groups associated with intestinal inflammation. Finally, an increase in methanogenic archaea such as Methanosphaera stadtmanae exhibits high immunogenic potential and is associated with CD etiology. Common anti-inflammatory medications used in CD management (amino-salicylates, immunomodulators, and biologics) could also directly or indirectly affect the gut microbiome in CD. Other medications often used concomitantly in IBD, such as antibiotics, antidepressants, oral contraceptives, opioids, and proton pump inhibitors, have shown to alter the gut microbiota and account for increased susceptibility to disease onset or worsening of disease progression. In contrast, some environmental modifications through alternative therapies including fecal microbiota transplant (FMT), diet and dietary supplements with prebiotics, probiotics, and synbiotics have shown potential protective effects by reversing microbiota dysbiosis or by directly promoting beneficial microbes, together with minimal long-term adverse effects. In this review, we discuss the different approaches to modulating the global consortium of bacteria, fungi, viruses, and archaea in patients with CD through therapies that include antibiotics, probiotics, prebiotics, synbiotics, personalized diets, and FMT. We hope to provide evidence to encourage clinicians and researchers to incorporate these therapies into CD treatment options, along with making them aware of the limitations of these therapies, and indicate where more research is needed.

Complementary and Alternative Medicine in Crohn's Disease

Complementary and alternative medicine (CAM) is a growing entity within inflammatory bowel disease (IBD). CAM includes mind-based therapies, body-based therapies, supplements, vitamins, and probiotics. Limitations currently exist for health care providers as it pertains to IBD and CAM that stem from knowledge gaps, conflicting reports, limited oversight, and a lack of well-organized clinical data. Even without well-described data, patients are turning to these forms of therapy at increasing rates. It is imperative that the ongoing review of CAM therapies is performed, and future trials are performed to better understand efficacy as well as adverse effects related to these therapies.

Inflammatory Bowel Disease Therapeutics: A Focus on Probiotic Engineering

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of gastrointestinal (GI) tract with dysregulated mucosal immune functions and disturbed commensal ecosystem of the intestinal lumen. IBD is categorized into two major subsets: Crohn's disease (CD) and ulcerative colitis (UC). Though advent of biologics has shifted the treatment with relatively longer remission compared to small molecule pharmaceuticals, patients still suffer from long-term complications. Since gut-microbiome is now accepted as another human organ holding potential for long-lasting human health, probiotics, and its engineering hold great promises to treat several previously untreatable chronic inflammatory conditions including IBD. Several emerging biological engineering tools have unlimited potential to manipulate probiotic bacterial system. These can produce useful therapeutic biologics with a goal to either ameliorate and/or treat previously untreatable chronic inflammatory conditions. As gut-microbiome is diverse and vary in different ethnic, geographic, and cultural human population, it will be important to develop vision for personalized probiotic treatment and develop the technology thereof to make personalized probiotic options a reality. The aim of this review paper is to present an overview of the current knowledge on both pharmacological and nonpharmacological IBD treatment modalities with a special emphasis on probiotic strains that are developed through the probiotic engineering. These engineered probiotics contain the most anti-inflammatory cytokines found within the human immune response and are currently being used to treat the intestinal inflammation in IBD for the IBD treatment.

Mining the Microbiome and Microbiota-Derived Molecules in Inflammatory Bowel Disease

The intestinal microbiota is a complex community that consists of an ecosystem with a dynamic interplay between bacteria, fungi, archaea, and viruses. Recent advances in model systems have revealed that the gut microbiome is critical for maintaining homeostasis through metabolic digestive function, immune regulation, and intestinal barrier integrity. Taxonomic shifts in the intestinal microbiota are strongly correlated with a multitude of human diseases, including inflammatory bowel disease (IBD). However, many of these studies have been descriptive, and thus the understanding of the cause and effect relationship often remains unclear. Using non-human experimental model systems such as gnotobiotic mice, probiotic mono-colonization, or prebiotic supplementation, researchers have defined numerous species-level functions of the intestinal microbiota that have produced therapeutic candidates for IBD. Despite these advances, the molecular mechanisms responsible for the function of much of the microbiota and the interplay with host cellular processes remain areas of tremendous research potential. In particular, future research will need to unlock the functional molecular units of the microbiota in order to utilize this untapped resource of bioactive molecules for therapy. This review will highlight the advances and remaining challenges of microbiota-based functional studies and therapeutic discovery, specifically in IBD. One of the limiting factors for reviewing this topic is the nascent development of this area with information on some drug candidates still under early commercial development. We will also highlight the current and evolving strategies, including in the biotech industry, used for the discovery of microbiota-derived bioactive molecules in health and disease.

The Relationship Between Endoscopic and Clinical Recurrence in Postoperative Crohn's Disease: A Systematic Review and Meta-analysis

BACKGROUND AND AIMS

We aimed to quantify the magnitude of the association between endoscopic recurrence and clinical recurrence [symptom relapse] in patients with postoperative Crohn's disease.

METHODS

Databases were searched to October 2, 2020, for randomised controlled trials [RCTs] and cohort studies of adult patients with Crohn's disease with ileocolonic resection and anastomosis. Summary effect estimates for the association between clinical recurrence and endoscopic recurrence were quantified by risk ratios [RR] and 95% confidence intervals [95% CI]. Mixed-effects meta-regression evaluated the role of confounders. Spearman correlation coefficients were calculated to assess the relationship between these outcomes as endpoints in RCTs. An exploratory mixed-effects meta-regression model with the logit of the rate of clinical recurrence as the outcome and the rate of endoscopic recurrence as a predictor was also evaluated.

RESULTS

In all, 37 studies [N = 4053] were included. For eight RCTs with available data, the RR for clinical recurrence for patients who experienced endoscopic recurrence was 10.77 [95% CI 4.08 to 28.40; GRADE moderate certainty evidence]; the corresponding estimate from 11 cohort studies was 21.33 [95% CI 9.55 to 47.66; GRADE low certainty evidence]. A single cohort study showed a linear relationship between Rutgeerts score and clinical recurrence risk. There was a strong correlation between endoscopic recurrence and clinical recurrence treatment effect estimates as trial outcomes [weighted Spearman correlation coefficient 0.51].

CONCLUSIONS

The associations between endoscopic recurrence and subsequent clinical recurrence lend support to the choice of endoscopic recurrence to monitor postoperative disease activity and as a primary endpoint in clinical trials of postoperative Crohn's disease.

Probiotics, Prebiotics and Synbiotics in Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD), which include Crohn's disease (CD) and ulcerative colitis (UC), are chronic inflammatory diseases of the digestive tract with periods of remission and relapses. The etiopathogenesis of IBD is multifactorial and has not been fully understood. Hence, only symptomatic treatment of these diseases is possible. The current pharmacological treatment has variable efficacy and is associated with the risk of significant side effects. Therefore, there is a constant need to search for new types of therapies with a high safety profile. Considering that the qualitative and quantitative profile of the gastrointestinal microbiome is often different in patients with IBD than in healthy individuals, there is a need for looking for therapies aimed at restoring intestinal microbiome homeostasis. Thus, the use of strictly defined probiotics, prebiotics and synbiotics may become an alternative form of IBD therapy. There is evidence that treatment with certain probiotic strains, e.g., VSL#3 and Escherischia coli Nissle 1917, is an effective form of therapy to induce remission in patients with mild to moderate UC. So far, the effectiveness of the use of probiotics, prebiotics and synbiotics in inducing or maintaining remission in patients with CD has not been confirmed. There are also reports of possible beneficial effects of fecal microbiota transplantation (FMT) on the course of IBD, especially UC. Further, well-planned studies on a large group of patients are needed to determine the role of specific probiotic strains, prebiotics, synbiotics and FMT in the treatment of IBD in adults and in children.

Medical therapies for postoperative Crohn's disease

Postoperative recurrence of Crohn's disease is common and requires a multidisciplinary approach between surgeons and gastroenterologists in the perioperative and postoperative period to improve outcomes in this patient population. Endoscopic recurrence precedes clinical and surgical recurrence and endoscopic monitoring is crucial to guide postoperative management. Risk stratification of patients is recommended to guide early prophylactic management, and follow-up endoscopic monitoring can guide intensification of therapy. This review summarizes evidence behind postoperative recurrence rates, disease monitoring techniques, nonbiologic and biologic therapies available to prevent and treat postoperative recurrence, risk factors associated with recurrence, and postoperative management strategies guided by endoscopic monitoring.

Gut microbiome a promising target for management of respiratory diseases

The intestinal microbial flora has risen to be one of the important etiological factors in the development of diseases like colorectal cancer, obesity, diabetes, inflammatory bowel disease, anxiety and Parkinson's. The emergence of the association between bacterial flora and lungs led to the discovery of the gut-lung axis. Dysbiosis of several species of colonic bacteria such as Firmicutes and Bacteroidetes and transfer of these bacteria from gut to lungs via lymphatic and systemic circulation are associated with several respiratory diseases such as lung cancer, asthma, tuberculosis, cystic fibrosis, etc. Current therapies for dysbiosis include use of probiotics, prebiotics and synbiotics to restore the balance between various species of beneficial bacteria. Various approaches like nanotechnology and microencapsulation have been explored to increase the permeability and viability of probiotics in the body. The need of the day is comprehensive study of mechanisms behind dysbiosis, translocation of microbiota from gut to lung through various channels and new technology for evaluating treatment to correct this dysbiosis which in turn can be used to manage various respiratory diseases. Microfluidics and organ on chip model are emerging technologies that can satisfy these needs. This review gives an overview of colonic commensals in lung pathology and novel systems that help in alleviating symptoms of lung diseases. We have also hypothesized new models to help in understanding bacterial pathways involved in the gut-lung axis as well as act as a futuristic approach in finding treatment of respiratory diseases caused by dysbiosis.

Gut Microbiota Profiles and Microbial-Based Therapies in Post-operative Crohn's Disease: A Systematic Review

Background and Aims: Gut microbiota recolonization after intestinal resection had been reported to be associated with post-operative recurrence in Crohn's disease (CD). However, the results of different studies are inconsistent and even contradictory. In addition, knowledge on the efficacy of microbial-based therapies in preventing post-operative recurrence of CD is limited. Therefore, the aim of this review was to investigate gut microbiota profiles in patients with CD before and after surgery and evaluate microbial-based therapies in preventing post-operative recurrence. Methods: Electronic databases were searched from inception to 31 June 2020 using predefined terms. Studies that investigated gut microbiota pre- and post-intestinal resection, and microbial-based therapies in preventing post-operative recurrence, were eligible. Study quality was assessed using either the Newcastle-Ottawa scale or Jadad scoring system. Results: Twelve studies investigating gut microbiota of CD patients suffering from operation, and other 12 studies evaluating the efficacy of antibiotics and probiotics, were included in our review. The mucosa-associated microbiota in surgical biopsy of CD patients is significantly distinct from that in normal mucosa from healthy subjects. Gut microbiota recolonization following surgery might be associated with post-operative recurrence in CD patients. Furthermore, CD patients with post-operative recurrence presented a gain in pro-inflammatory pathogenic bacteria and a loss in short-chain fatty acid-producing bacteria before and after surgery. However, no consistent bacteria or metabolites were found to predict the post-operative recurrence of CD. Additionally, microbial-based therapies are deficient and present restricted widespread clinical utility due to several deficiencies. Conclusion: Recurrence-associated bacteria observed pre- and post- operation might be promising in preventing the post-operative recurrence of CD. Furthermore, potential microbe biomarkers for predicting subsequent disease recurrence should be validated with larger sample sizes using more rigorous and standardized methodologies.

Prevention of Postoperative Recurrence in CD: Tailoring Treatment to Patient Profile

Crohn's disease (CD) is an immune-mediated condition characterized by the transmural inflammation of the gut tissue, associated with progressive bowel damage often leading to surgical intervention. As operative resection of the damaged segment is not curative, a majority of patients undergoing intestinal resections for complicated CD present disease recurrence within 3 years after the intervention. Postoperative recurrence can be defined as endoscopic, clinical, radiological or surgical. Endoscopic recurrence rates within 1 year exceed 60% and the severity, according to the Rutgeerts' score, is associated with worse prognosis and can predict clinical recurrence (in up to 1/3 of the patients). Most importantly, about 50% of patients will undergo a reoperation after 10 years of their first intestinal resection. Therefore, the prevention of postoperative recurrence in CD remains a challenge in clinical practice and should be properly managed. We aim to summarize the most recent data on the definition, risk factors, assessment and treatment of postoperative CD recurrence.

Probiotic Lactobacillus and Bifidobacterium Strains Counteract Adherent-Invasive Escherichia coli (AIEC) Virulence and Hamper IL-23/Th17 Axis in Ulcerative Colitis, but Not in Crohn's Disease

Hypersecretion of proinflammatory cytokines and dysregulated activation of the IL-23/Th17 axis in response to intestinal microbiota dysbiosis are key factors in the pathogenesis of inflammatory bowel diseases (IBD). In this work, we studied how Lactobacillus and Bifidobacterium strains affect AIEC-LF82 virulence mechanisms and the consequent inflammatory response linked to the CCR6–CCL20 and IL-23/Th17 axes in Crohn’s disease (CD) and ulcerative colitis (UC) patients. All Lactobacillus and Bifidobacterium strains significantly reduced the LF82 adhesion and persistence within HT29 intestinal epithelial cells, inhibiting IL-8 secretion while not affecting the CCR6–CCL20 axis. Moreover, they significantly reduced LF82 survival within macrophages and dendritic cells, reducing the secretion of polarizing cytokines related to the IL-23/Th17 axis, both in healthy donors (HD) and UC patients. In CD patients, however, only B. breve Bbr8 strain was able to slightly reduce the LF82 persistence within dendritic cells, thus hampering the IL-23/Th17 axis. In addition, probiotic strains were able to modulate the AIEC-induced inflammation in HD, reducing TNF-α and increasing IL-10 secretion by macrophages, but failed to do so in IBD patients. Interestingly, the probiotic strains studied in this work were all able to interfere with the IL-23/Th17 axis in UC patients, but not in CD patients. The different interaction mechanisms of probiotic strains with innate immune cells from UC and CD patients compared to HD suggest that testing on CD-derived immune cells may be pivotal for the identification of novel probiotic strains that could be effective also for CD patients.

Probiotics and Probiotic-Derived Functional Factors-Mechanistic Insights Into Applications for Intestinal Homeostasis

Advances in our understanding of the contribution of the gut microbiota to human health and the correlation of dysbiosis with diseases, including chronic intestinal conditions such as inflammatory bowel disease (IBD), have driven mechanistic investigations of probiotics in intestinal homeostasis and potential clinical applications. Probiotics have been shown to promote intestinal health by maintaining and restoring epithelial function, ensuring mucosal immune homeostasis, and inhibiting pathogenic bacteria. Recent findings reveal an approach for defining previously unrecognized probiotic-derived soluble factors as potential mechanisms of probiotic action. This review focuses on the impact of probiotics and probiotic-derived functional factors, including probiotic products and metabolites by probiotics, on the cellular responses and signaling pathways involved in maintaining intestinal homeostasis. Although there is limited information regarding the translation of probiotic treatment outcomes from in vitro and animal studies to clinical applications, potential approaches for increasing the clinical efficacy of probiotics for IBD, such as those based on probiotic-derived factors, are highlighted in this review. In this era of precision medicine and targeted therapies, more basic, preclinical, and clinical evidence is needed to clarify the efficacy of probiotics in maintaining intestinal health and preventing and treating disease.

Anti-Inflammatory and Gut Microbiota Modulatory Effect of Lactobacillus rhamnosus Strain LDTM 7511 in a Dextran Sulfate Sodium-Induced Colitis Murine Model

Inflammatory bowel disease (IBD) is a group of conditions involving chronic relapsing-remitting inflammation of the gastrointestinal tract with an unknown etiology. Although the cause-effect relationship between gut microbiota and IBD has not been clearly established, emerging evidence from experimental models supports the idea that gut microbes play a fundamental role in the pathogenesis of IBD. As microbiome-based therapeutics for IBD, the beneficial effects of probiotics have been found in animal colitis models and IBD patients. In this study, based on the dextran sulfate sodium (DSS)-induced colitis mouse model, we investigated Lactobacillus rhamnosus strain LDTM 7511 originating from Korean infant feces as a putative probiotic strain for IBD. The strain LDTM 7511 not only alleviated the release of inflammatory mediators, but also induced the transition of gut microbiota from dysbiotic conditions, exhibiting the opposite pattern in the abundance of DSS colitis-associated bacterial taxa to the DSS group. Our findings suggest that the strain LDTM 7511 has the potential to be used as a probiotic treatment for IBD patients in comparison to L. rhamnosus GG (ATCC 53103), which has been frequently used for IBD studies.

Complementary and alternative medications in the management of inflammatory bowel disease

The use of complementary and alternative medications (CAM), products, and therapies not considered to be part of conventional medicine is common among patients with inflammatory bowel disease (IBD). Patients often turn to these therapies as they are considered natural and safe, with significant benefit reported beyond disease control. There is emerging evidence that some of these therapies may have anti-inflammatory activity; however, robust evidence for their efficacy in modulating disease activity is currently lacking. Patients often avoid discussing the use of CAM with their physicians, which may lead to drug interactions and/or reduced adherence with conventional therapy. It is important for physicians to be aware of the commonly used CAM and current evidence behind these therapies in order to better counsel their patients about their use in the management of IBD. This narrative review provides an overview of the evidence of the more commonly used CAM in patients with IBD.

Effectiveness of probiotics, prebiotics, and prebiotic-like components in common functional foods

The bioactive ingredients in commonly consumed foods include, but are not limited to, prebiotics, prebiotic-like components, probiotics, and postbiotics. The bioactive ingredients in functional foods have also been associated with beneficial effects on human health. For example, they aid in shaping of gut microflora and promotion of immunity. These functional components also contribute in preventing serious diseases such as cardiovascular malfunction and tumorigenesis. However, the specific mechanisms of these positive influences on human health are still under investigation. In this review, we aim to emphasize the major contents of probiotics, prebiotics, and prebiotic-like components commonly found in consumable functional foods, and we present an overview of direct and indirect benefits they provide on human health. The major contributors are certain families of metabolites, specifically short-chain fatty acids and polyunsaturated fatty acids produced by probiotics, and prebiotics, or prebiotic-like components such as flavonoids, polyphenols, and vitamins that are found in functional foods. These functional ingredients in foods influence the gut microbiota by stimulating the growth of beneficial microbes and the production of beneficial metabolites that, in turn, have direct benefits to the host, while also providing protection from pathogens and maintaining a balanced gut ecosystem. The complex interactions that arise among functional food ingredients, human physiology, the gut microbiota, and their respective metabolic pathways have been found to minimize several factors that contribute to the incidence of chronic disease, such as inflammation oxidative stress.

Perioperative Dietary Therapy in Inflammatory Bowel Disease

BACKGROUND AND AIMS

The incidence of inflammatory bowel disease [IBD] is rising worldwide and no cure is available. Many patients require surgery and they often present with nutritional deficiencies. Although randomised controlled trials of dietary therapy are lacking, expert IBD centres have long-established interdisciplinary care, including tailored nutritional therapy, to optimise clinical outcomes and resource utilisation. This topical review aims to share expertise and offers current practice recommendations to optimise outcomes of IBD patients who undergo surgery.

METHODS

A consensus expert panel consisting of dietitians, surgeons, and gastroenterologists, convened by the European Crohn's and Colitis Organisation, performed a systematic literature review. Nutritional evaluation and dietary needs, perioperative optimis ation, surgical complications, long-term needs, and special situations were critically appraised. Statements were developed using a Delphi methodology incorporating three successive rounds. Current practice positions were set when ≥80% of participants agreed on a recommendation.

RESULTS

A total of 26 current practice positions were formulated which address the needs of IBD patients perioperatively and in the long term following surgery. Routine screening, perioperative optimisation by oral, enteral, or parenteral nutrition, dietary fibre, and supplements were reviewed. IBD-specific situations, including management of patients with a restorative proctocolectomy, an ostomy, strictures, or short-bowel syndrome, were addressed.

CONCLUSIONS

Perioperative dietary therapy improves the outcomes of IBD patients who undergo a surgical procedure. This topical review shares interdisciplinary expertise and provides guidance to optimise the outcomes of patients with Crohn's disease and ulcerative colitis. taking advantage of contemporary nutrition science.

Disease managing capacities and mechanisms of host effects of lactic acid bacteria

Consumption of lactic acid bacteria (LAB) has been suggested to confer health-promoting effects on the host. However, effects of LABs have been reported to be species- and strain-specific and the mechanisms involved are subjects of discussion. Here, the possible mechanisms by which LABs induce antipathogenic, gut barrier enhancing and immune modulating effects in consumers are reviewed. Specific strains for which it has been proven that health is improved by these mechanisms are discussed. However, most strains probably act via several or combinations of mechanisms depending on which effector molecules they express. Current insight is that these effector molecules are either present on the cell wall of LAB or are excreted. These molecules are reviewed as well as the ligand binding receptors in the host. Also postbiotics are discussed. Finally, we provide an overview of the efficacy of LABs in combating infections caused by Helicobacter pylori, Salmonella, Escherichia coli, Streptococcus pneumoniae, and influenza virus, in controlling gut inflammatory diseases, in managing allergic disorders, and in alleviating cancer.

ESPEN practical guideline: Clinical Nutrition in inflammatory bowel disease

The present guideline is the first of a new series of "practical guidelines" based on more detailed scientific guidelines produced by ESPEN during the last few years. The guidelines have been shortened and now include flow charts that connect the individual recommendations to logical care pathways and allow rapid navigation through the guideline. The purpose of the present practical guideline is to provide an easy-to-use tool to guide nutritional support and primary nutritional therapy in inflammatory bowel disease (IBD). The guideline is aimed at professionals working in clinical practice, either in hospitals or in outpatient medicine, and treating patients with IBD. In 40 recommendations, general aspects of care in patients with IBD, and specific aspects during active disease and in remission are addressed. All recommendations are equipped with evidence grades, consensus rates, short commentaries and links to cited literature.

Prebiotics and Probiotics in Inflammatory Bowel Disease: Where are we now and where are we going?

The incidence, prevalence, and cost of care associated with diagnosis and management of inflammatory bowel disease are on the rise. The role of gut microbiota in the causation of Crohn's disease and ulcerative colitis has not been established yet. Nevertheless, several animal models and human studies point towards the association. Targeting intestinal dysbiosis for remission induction, maintenance, and relapse prevention is an attractive treatment approach with minimal adverse effects. However, the data is still conflicting. The purpose of this article is to provide the most comprehensive and updated review on the utility of prebiotics and probiotics in the management of active Crohn's disease and ulcerative colitis/pouchitis and their role in the remission induction, maintenance, and relapse prevention. A thorough literature review was performed on PubMed, Ovid Medline, and EMBASE using the terms "prebiotics AND ulcerative colitis", "probiotics AND ulcerative colitis", "prebiotics AND Crohn's disease", "probiotics AND Crohn's disease", "probiotics AND acute pouchitis", "probiotics AND chronic pouchitis" and "prebiotics AND pouchitis". Observational studies and clinical trials conducted on humans and published in the English language were included. A total of 71 clinical trials evaluating the utility of prebiotics and probiotics in the management of inflammatory bowel disease were reviewed and the findings were summarized. Most of these studies on probiotics evaluated lactobacillus, De Simone Formulation or Escherichia coli Nissle 1917 and there is some evidence supporting these agents for induction and maintenance of remission in ulcerative colitis and prevention of pouchitis relapse with minimal adverse effects. The efficacy of prebiotics such as fructooligosaccharides and Plantago ovata seeds in ulcerative colitis are inconclusive and the data regarding the utility of prebiotics in pouchitis is limited. The results of the clinical trials for remission induction and maintenance in active Crohn's disease or post-operative relapse with probiotics and prebiotics are inadequate and not very convincing. Prebiotics and probiotics are safe, effective and have great therapeutic potential. However, better designed clinical trials in the multicenter setting with a large sample and long duration of intervention are needed to identify the specific strain or combination of probiotics and prebiotics which will be more beneficial and effective in patients with inflammatory bowel disease.

Side Effects Associated with Probiotic Use in Adult Patients with Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Probiotics demonstrated to be effective in the treatment of inflammatory bowel disease (IBD). However, the safety profile of probiotics is insufficiently explored. In the present systematic review and meta-analysis, we examined the occurrence of side effects related to probiotic/synbiotic use in randomized controlled trials (RCTs) of IBD patients as compared with placebo. Eligible RCTs in adult patients with IBD were identified by accessing the Medline database via PubMed, EMBASE, CENTRAL and the Cochrane central register of controlled trials up to December 2018. Occurrence of side effects was retrieved and recorded. Data were pooled and the relative risks (RRs) with their 95% confidence intervals (CIs) were calculated. The low-moderate study heterogeneity, assessed by the I2 statistic, allowed to use of a fixed-effects modelling for meta-analysis. Nine RCTs among 2337, including 826 patients (442 treated with probiotics/symbiotic and 384 with placebo) were analyzed. Eight were double-blind RCTs, and six enrolled ulcerative colitis (UC) patients. Although the risk for the overall side effects (RR 1.35, 95%CI 0.93-1.94; I2 = 25%) and for gastrointestinal symptoms (RR 1.78, 95%CI 0.99-3.20; I2 = 20%) was higher in IBD patients taking probiotics than in those exposed to placebo, statistical significance was achieved only for abdominal pain (RR 2.59, 95%CI 1.28-5.22; I2 = 40%). In conclusion, despite the small number of RCTs and the variety of probiotic used and schedule across studies, these findings highlight the level of research effort still required to identify the most appropriate use of probiotics in IBD.

Microbiota modulation-based therapy for luminal GI disorders: current applications of probiotics and fecal microbiota transplantation

Introduction: Alteration in the intestinal microbiota also termed as intestinal dysbiosis has been demonstrated in numerous gastrointestinal disorders linked to aberrant immune processes, acquisition of pathogenic organisms and often administration of antibiotics. Restoration of microbiota through probiotics and fecal microbiota transplantation (FMT) has gained tremendous popularity among researchers in the prevention and treatment of gastrointestinal diseases.Areas covered: In this review, studies testing the safety and efficacy of probiotics and FMT for the treatment of various infectious and inflammatory luminal gastrointestinal diseases are reviewed. Randomized control studies are given priority while important uncontrolled studies are also highlighted.Expert opinion: Probiotics have demonstrated efficacy in the prevention of antibiotic-associated diarrhea and in the eradication of Helicobacter pylori infection. Their utility in the primary and secondary prevention of Clostridioides difficile infection is debatable. The future of medicine should bring forth a personalized approach to probiotic use. FMT has revolutionized the treatment of recurrent CDI as well as severe and fulminant CDI. At the same time, it has galvanized gut microbiota research in the last decade. While FMT in ulcerative colitis appears promising, further studies on the durability and long-term safety are needed before it can be recommended in clinical practice.

Treatment-Specific Composition of the Gut Microbiota Is Associated With Disease Remission in a Pediatric Crohn's Disease Cohort

BACKGROUND

The beneficial effects of antibiotics in Crohn's disease (CD) depend in part on the gut microbiota but are inadequately understood. We investigated the impact of metronidazole (MET) and metronidazole plus azithromycin (MET+AZ) on the microbiota in pediatric CD and the use of microbiota features as classifiers or predictors of disease remission.

METHODS

16S rRNA-based microbiota profiling was performed on stool samples from 67 patients in a multinational, randomized, controlled, longitudinal, 12-week trial of MET vs MET+AZ in children with mild to moderate CD. Profiles were analyzed together with disease activity, and then used to construct random forest models to classify remission or predict treatment response.

RESULTS

Both MET and MET+AZ significantly decreased diversity of the microbiota and caused large treatment-specific shifts in microbiota structure at week 4. Disease remission was associated with a treatment-specific microbiota configuration. Random forest models constructed from microbiota profiles before and during antibiotic treatment with metronidazole accurately classified disease remission in this treatment group (area under the curve [AUC], 0.879; 95% confidence interval, 0.683-0.9877; sensitivity, 0.7778; specificity, 1.000; P < 0.001). A random forest model trained on pre-antibiotic microbiota profiles predicted disease remission at week 4 with modest accuracy (AUC, 0.8; P = 0.24).

CONCLUSIONS

MET and MET+AZ antibiotic regimens in pediatric CD lead to distinct gut microbiota structures at remission. It may be possible to classify and predict remission based in part on microbiota profiles, but larger cohorts will be needed to realize this goal.

Low-Dose Metronidazole is Associated With a Decreased Rate of Endoscopic Recurrence of Crohn's Disease After Ileal Resection: A Retrospective Cohort Study

BACKGROUND AND AIMS

Recurrence of Crohn's disease after surgical resection and primary anastomosis is an important clinical challenge. Previous studies have demonstrated the benefit of imidazole antibiotics, but have been limited by adverse events and medication intolerance. We evaluated whether administration of low-dose metronidazole [250 mg three times per day] for 3 months reduces endoscopic postoperative recurrence rates.

METHODS

We performed a retrospective cohort study of patients with Crohn's disease who underwent ileal resection with a primary anastomosis and subsequently received care at our center. We compared the cases who received low-dose metronidazole for 3 months with control patients who did not receive this therapy. Data collected included demographics, risk factors for recurrence, and medications before and after surgery. The primary end point was the number of patients with ≥i2 [Rutgeerts] endoscopic recurrence by 12 months. Variables found to be predictive in univariate analysis at p < 0.10 were introduced in the Cox model for multivariate analysis.

RESULTS

In all, 70 patients with Crohn's disease [35 cases and 35 controls] met inclusion criteria. Risk factors for Crohn's recurrence were similar between groups. The number of patients with ≥i2 endoscopic recurrence within 12 months following ileal resection was significantly lower in the metronidazole group [7 of 35 patients; 20%] compared with the number in the control group [19 of 35 patients; 54.3%] [p = 0.0058]. Eight participants [22.9%] in the metronidazole group experienced adverse events, and 3 of these patients [8.6%] discontinued the therapy.

CONCLUSION

Low-dose metronidazole reduces endoscopic recurrence of Crohn's disease postoperatively and is well tolerated. This intervention should be considered as a therapy option following ileocolonic resection.

Interventions for maintenance of surgically induced remission in Crohn's disease: a network meta-analysis

BACKGROUND

Crohn's disease (CD) is a chronic disease of the gut. About 75% of people with CD undergo surgery at least once in their lifetime to induce remission. However, as there is no known cure for the disease, patients usually experience a recurrence even after surgery. Different interventions are routinely used in maintaining postsurgical remission. There is currently no consensus on which treatment is the most effective.

OBJECTIVES

To assess the effects and harms of interventions for the maintenance of surgically induced remission in Crohn's disease and rank the treatments in order of effectiveness.

SEARCH METHODS

We searched the Cochrane IBD Group Specialized Register, CENTRAL, MEDLINE, and Embase from inception to 15 January 2019. We also searched reference lists of relevant articles, abstracts from major gastroenterology meetings, ClinicalTrials.gov, and the WHO ICTRP. There was no restriction on language, date, or publication status.

SELECTION CRITERIA

We considered for inclusion randomised controlled trials (RCTs) that compared different interventions used for maintaining surgically induced remission in people with CD who were in postsurgical remission. Participants had to have received maintenance treatment for at least three months. We excluded studies assessing enteral diet, diet manipulation, herbal medicine, and nutritional supplementation.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected relevant studies, extracted data, and assessed the risk of bias. Any disagreements were resolved by discussion or by arbitration of a third review author when necessary. We conducted a network meta-analysis (NMA) using a Bayesian approach through Markov Chain Monte Carlo (MCMC) simulation. For the pairwise comparisons carried out in Review Manager 5, we calculated risk ratios (RR) with their corresponding 95% confidence intervals (95% CI). For the NMA, we presented hazard ratios (HR) with corresponding 95% credible intervals (95% CrI) and reported ranking probabilities for each intervention. For the NMA, we focused on three main outcomes: clinical relapse, endoscopic relapse, and withdrawals due to adverse events. Data were insufficient to assess time to relapse and histologic relapse. Adverse events and serious adverse events were not sufficiently or objectively reported to permit an NMA. We used CINeMA (Confidence in Network Meta-Analysis) methods to evaluate our confidence in the findings within networks, and GRADE for entire networks.

MAIN RESULTS

We included 35 RCTs (3249 participants) in the review. The average age of study participants ranged between 33.6 and 38.8 years. Risk of bias was high in 18 studies, low in four studies, and unclear in 13 studies. Of the 35 included RCTs, 26 studies (2581 participants; 9 interventions) were considered eligible for inclusion in the NMA. The interventions studied included 5-aminosalicylic acid (5-ASA), adalimumab, antibiotics, budesonide, infliximab, probiotics, purine analogues, sulfasalazine, and a combination of sulfasalazine and prednisolone. This resulted in 30 direct contrasts, which informed 102 mixed-treatment contrasts.The evidence for the clinical relapse network (21 studies; 2245 participants) and endoscopic relapse (12 studies; 1128 participants) were of low certainty while the evidence for withdrawal due to adverse events (15 studies; 1498 participants) was of very low certainty. This assessment was due to high risk of bias in most of the studies, inconsistency, and imprecision across networks. We mainly judged individual contrasts as of low or very low certainty, except 5-ASA versus placebo, the evidence for which was judged as of moderate certainty.We ranked the treatments based on effectiveness and the certainty of the evidence. For clinical relapse, the five most highly ranked treatments were adalimumab, infliximab, budesonide, 5-ASA, and purine analogues. We found some evidence that adalimumab (HR 0.11, 95% Crl 0.02 to 0.33; low-certainty evidence) and 5-ASA may reduce the probability of clinical relapse compared to placebo (HR 0.69, 95% Crl 0.53 to 0.87; moderate-certainty evidence). However, budesonide may not be effective in preventing clinical relapse (HR 0.66, 95% CrI 0.27 to 1.34; low-certainty evidence). We are less confident about the effectiveness of infliximab (HR 0.36, 95% CrI 0.02 to 1.74; very low-certainty evidence) and purine analogues (HR 0.75, 95% CrI 0.55 to 1.00; low-certainty evidence). It was unclear whether the other interventions reduced the probability of a clinical relapse, as the certainty of the evidence was very low.Due to high risk of bias and limited data across the network, we are uncertain about the effectiveness of interventions for preventing endoscopic relapse. Whilst there might be some evidence of prevention of endoscopic relapse with adalimumab (HR 0.10, 95% CrI 0.01 to 0.32; low-certainty evidence), no other intervention studied appeared to be effective.Due to high risk of bias and limited data across the network, we are uncertain about the effectiveness of interventions for preventing withdrawal due to adverse events. Withdrawal due to adverse events appeared to be least likely with sulfasalazine (HR 1.96, 95% Crl 0.00 to 8.90; very low-certainty evidence) and most likely with antibiotics (HR 53.92, 95% Crl 0.43 to 259.80; very low-certainty evidence). When considering the network as a whole, two adverse events leading to study withdrawal (i.e. pancreatitis and leukopenia) occurred in more than 1% of participants treated with an intervention. Pancreatitis occurred in 2.8% (11/399) of purine analogue participants compared to 0.17% (2/1210) of all other groups studied. Leukopenia occurred in 2.5% (10/399) of purine analogue participants compared to 0.08% (1/1210) of all other groups studied.

AUTHORS' CONCLUSIONS

Due to low-certainty evidence in the networks, we are unable to draw conclusions on which treatment is most effective for preventing clinical relapse and endoscopic relapse. Evidence on the safety of the interventions was inconclusive, however cases of pancreatitis and leukopenia from purine analogues were evident in the studies. Larger trials are needed to further understand the effect of the interventions on endoscopic relapse.