The Gut Microbiome and the Triple Environmental Hit Concept of Inflammatory Bowel Disease Pathogenesis

Patient-derived organoid biobank identifies epigenetic dysregulation of intestinal epithelial MHC-I as a novel mechanism in severe Crohn's Disease

OBJECTIVE

Epigenetic mechanisms, including DNA methylation (DNAm), have been proposed to play a key role in Crohn's disease (CD) pathogenesis. However, the specific cell types and pathways affected as well as their potential impact on disease phenotype and outcome remain unknown. We set out to investigate the role of intestinal epithelial DNAm in CD pathogenesis.

DESIGN

We generated 312 intestinal epithelial organoids (IEOs) from mucosal biopsies of 168 patients with CD (n=72), UC (n=23) and healthy controls (n=73). We performed genome-wide molecular profiling including DNAm, bulk as well as single-cell RNA sequencing. Organoids were subjected to gene editing and the functional consequences of DNAm changes evaluated using an organoid-lymphocyte coculture and a nucleotide-binding oligomerisation domain, leucine-rich repeat and CARD domain containing 5 (NLRC5) dextran sulphate sodium (DSS) colitis knock-out mouse model.

RESULTS

We identified highly stable, CD-associated loss of DNAm at major histocompatibility complex (MHC) class 1 loci including NLRC5 and cognate gene upregulation. Single-cell RNA sequencing of primary mucosal tissue and IEOs confirmed the role of NLRC5 as transcriptional transactivator in the intestinal epithelium. Increased mucosal MHC-I and NLRC5 expression in adult and paediatric patients with CD was validated in additional cohorts and the functional role of MHC-I highlighted by demonstrating a relative protection from DSS-mediated mucosal inflammation in NLRC5-deficient mice. MHC-I DNAm in IEOs showed a significant correlation with CD disease phenotype and outcomes. Application of machine learning approaches enabled the development of a disease prognostic epigenetic molecular signature.

CONCLUSIONS

Our study has identified epigenetically regulated intestinal epithelial MHC-I as a novel mechanism in CD pathogenesis.

MYO5B and the Polygenic Landscape of Very Early-Onset Inflammatory Bowel Disease in an Ethnically Diverse Population

BACKGROUND

Genetic discovery in very early-onset inflammatory bowel disease (VEO-IBD) can elucidate not only the origins of VEO-IBD, but also later-onset inflammatory bowel disease. We aimed to investigate the polygenic origins of VEO-IBD in a cohort with a high proportion of Hispanic patients.

METHODS

Patients with VEO-IBD who underwent whole exome sequencing at our center were included. Genes were categorized as genes of interest (GOIs) (129 genes previously described to be associated with VEO-IBD) or non-GOIs. VEO-IBD "susceptibility" single nucleotide variants (SNVs) were identified through enrichment compared with gnomAD (Genome Aggregation Database) and ALFA (Allele Frequency Aggregator) and were scored by Combined Annotation Dependent Depletion for deleteriousness. Gene networks carrying susceptibility SNVs were created. Myosin 5b immunofluorescence was also studied.

RESULTS

Fifty-six patients met inclusion criteria, and 32.1% identified as Hispanic. Monogenic disease was infrequent (8.9%). Significant enrichment of GOI susceptibility SNVs was observed, notably in MYO5B, especially in Hispanics. MEFV, TNFAIP3, SH3TC2, and NCF2 were also central participants in the GOI networks. Myosin 5b immunofluorescence in colonic mucosa was significantly reduced in those with MYO5B susceptibility SNVs compared with control subjects. Seven genes (ESRRA, HLA-DQ1, RETSAT, PABPC1, PARP4, CCDC102A, and SUSD2) were central participants in the non-GOI networks.

CONCLUSIONS

Our results support the polygenic nature of VEO-IBD, in which key participants, like MYO5B, were identified through network analytics. Rare variant load within susceptibility genes may be relevant not only for the genetic origins of inflammatory bowel disease, but also for the age of disease onset. Our findings could guide future work in precision medicine.

Effects of Milk and Dairy on the Risk and Course of Inflammatory Bowel Disease versus Patients' Dietary Beliefs and Practices: A Systematic Review

BACKGROUND

The role of the environment in the pathogenesis of inflammatory bowel disease (IBD) is undisputed, especially in light of numerous epidemiological data showing the increasing prevalence of IBD worldwide. Although no specific environmental factors have been identified, the diet has received the most attention as a potential modifier of the onset and course of IBD and as a therapeutic intervention. The Westernization of the diet is repeatedly cited as a crucial aspect of the change in IBD prevalence, but data on the impact of diet on the course of IBD are still limited and the effectiveness of dietary interventions remains uncertain. Milk remains one of the most discussed dietary agents in IBD.

MATERIALS AND METHODS

We performed a systematic review of the literature published between January 2010 and March 2024 on three databases, Pubmed, Web of Knowledge, and Embase, to assess the impact of milk and dairy products on the risk and course of IBD, as well as patients' dietary beliefs and practices.

RESULTS

We included 37 original studies in our review.

CONCLUSIONS

There is no clear evidence that milk and dairy products influence the incidence and course of IBD. The studies that assess this issue are characterized by great heterogeneity. Milk and dairy are among the most commonly excluded foods by patients with IBD, which may have clinical implications.

Gastrointestinal problems in a valproic acid-induced rat model of autism: From maternal intestinal health to offspring intestinal function

BACKGROUND

Autism spectrum disorder (ASD) is a developmental disorder characterized by social deficits and repetitive behavior. Gastrointestinal (GI) problems, such as constipation, diarrhea, and inflammatory bowel disease, commonly occur in patients with ASD. Previously, GI problems of ASD patients were attributed to intestinal inflammation and vertical mother-to-infant microbiome transmission.

AIM

To explore whether GI problems in ASD are related to maternal intestinal inflammation and gut microbiota abnormalities.

METHODS

An ASD rat model was developed using valproic acid (VPA). Enzyme-linked immunosorbent assay and fecal 16S rRNA sequencing were used to test GI changes.

RESULTS

VPA exposure during pregnancy led to pathological maternal intestinal changes, resulting in alterations in maternal gut microbiota. Additionally, the levels of inflammatory factors also increased. Moreover, prenatal exposure to VPA resulted in impaired duodenal motility in the offspring as well as increased levels of inflammatory factors.

CONCLUSION

GI problems in ASD may be associated with maternal intestinal inflammation and microbiota abnormality. Future research is required to find more evidence on the etiology and treatment of GI problems in ASD.

The Diagnosis of Intestinal Fibrosis in Crohn's Disease-Present and Future

Crohn's disease (CD) progresses with periods of remission and exacerbations. During exacerbations, chronic inflammation leads to tissue destruction. As a result, intestinal fibrosis may develop in response to the ongoing inflammatory process. Fibrosis in CD should be considered the result of the response of the intestinal wall (over) to the presence of inflammation in the deep structures of the intestinal wall. In the absence of ideal noninvasive methods, endoscopic evaluation in combination with biopsy, histopathological analysis, stool analysis, and blood analysis remains the gold standard for assessing both inflammation and fibrosis in CD. On the contrary, the ability to identify markers of intestinal fibrosis would help to develop new diagnostic and therapeutic methods to detect early stages of fibrosis. It is speculated that miRNAs may, in the future, become biomarkers for early noninvasive diagnosis in the treatment of intestinal fibrosis. The purpose of this review is to summarise existing diagnostic methods for Crohn's disease and present recent scientific reports on molecular testing.

Identifying a therapeutic window of opportunity for people living with primary sclerosing cholangitis: Embryology and the overlap of inflammatory bowel disease with immune-mediated liver injury

Primary sclerosing cholangitis (PSC) is a variably progressive, fibrosis-causing autoimmune disorder of the intrahepatic and extrahepatic bile ducts of unclear etiology. PSC is commonly (in 60%-90% of cases) associated with an inflammatory bowel disease (IBD) like PSC-IBD and less commonly with an autoimmune hepatitis (AIH) like PSC-AIH or AIH-overlap disorder. Hepatologists and Gastroenterologists often consider these combined conditions as distinctly different from the classical forms in isolation. Here, we review recent epidemiologic observations and highlight that PSC-IBD and PSC-AIH overlap appear to represent aspects of a common PSC clinico-pathological pathway and manifest in an age-of-presentation-dependent manner. Particularly from the pediatric experience, we hypothesize that all cases of PSC likely originate from a complex "Early PSC"-"IBD"-"AIH" overlap in which PSC defines the uniquely and variably associated "AIH" and "IBD" components along an individualized lifetime continuum. We speculate that a distinctly unique, "diverticular autoimmunity" against the embryonic cecal- and hepatic diverticulum-derived tissues may be the origin of this combined syndrome, where "AIH" and "IBD" variably commence then variably fade while PSC progresses with age. Our hypothesis provides an explanation for the age-dependent variation in the presentation and progression of PSC. This is critical for the optimal targeting of studies into PSC etiopathogenesis and emphasizes the concept of a "developmental window of opportunity for therapeutic mitigation" in what is currently recognized as an irreversible disease process. The discovery of such a window would be critically important for the targeting of interventions, both the administration of current therapies and therapeutic trial planning.

NOD2 Polymorphisms May Direct a Crohn Disease Phenotype in Patients With Very Early-Onset Inflammatory Bowel Disease

NOD2/CARD15 was the first susceptibility gene recognized for adult-onset Crohn's (or Crohn) disease (CD). Recessive inheritance of NOD2 polymorphisms has been implicated as a mechanistic driver of pediatric-onset CD. In patients with very early-onset inflammatory bowel disease (VEO-IBD), however, the clinical relevance of NOD2 polymorphisms has not been fully established. Ten VEO-IBD patients with NOD2 polymorphisms ( NOD2 +) were compared to 16 VEO-IBD patients without genetic variants in NOD2 or any other VEO-IBD susceptibility genes ( NOD2 -). The majority of NOD2 + patients exhibited a CD-like phenotype (90%), linear growth impairment (90%), and arthropathy (60%), all of which were significantly more common than in the NOD2 - group ( P = 0.037, P = 0.004, P = 0.026, respectively). We propose that the presence of NOD2 polymorphisms in patients with VEO-IBD might confer a CD-like phenotype, linear growth impairment, and arthropathy. These findings should be validated in larger cohorts and may guide precision medicine for patients with VEO-IBD in the future.

Gut Microbiota Composition Changes following Discontinuation of Exclusive Enteral Nutrition in Children with Crohn's Disease

This study aims to determine changes in the intestinal microbiota of children with Crohn's disease (CD) before and during exclusive enteral nutrition (EEN) and after its discontinuation. A total of 14 newly diagnosed children with CD (median age 16.0 years; 43% female) were included in this study. Patients were initially treated with EEN and were followed for one year after EEN discontinuation. Stool samples were taken at the time of diagnosis (before EEN introduction), the second day of EEN, the last day of EEN, and every two months for one year after the discontinuation of EEN. A molecular approach targeting 16S ribosomal RNA was used for analysing the gut microbiota. No change was found in the Shannon diversity index before, during, and after EEN cessation (HhaI-digestion p = 0.82; MspI-digestion p = 0.87). According to the PCO, on the basis of the dissimilarity matrices of OTUs, a clear separation of patients at different time points, forming two clusters (before and during EEN as opposed to after EEN), was evident. No clear separation was noted between patients who achieved sustained remission as opposed to those who did not achieve sustained remission during EEN and at the follow-up. In conclusion, a distinct change in the microbiota composition already occurred after two months of EEN discontinuation and remained mostly unchanged over a year of follow-up.

Personalised azithromycin+metronidazole (PAZAZ), in combination with standard induction therapy, to achieve a faecal microbiome community structure and metagenome changes associated with sustained remission in paediatric Crohn's disease (CD): protocol of a pilot study

INTRODUCTION

Early relapse in Crohn's disease (CD) is associated with a more severe disease course. The microbiome plays a crucial role, yet strategies targeting the microbiome are underrepresented in current guidelines. We hypothesise that early manipulation of the microbiome will improve clinical response to standard-of-care (SOC) induction therapy in patients with a relapse-associated microbiome profile. We describe the protocol of a pilot study assessing feasibility of treatment allocation based on baseline faecal microbiome profiles.

METHODS AND ANALYSIS

This is a 52-week, multicentre, randomised, controlled, open-label, add-on pilot study to test the feasibility of a larger multicontinent trial evaluating the efficacy of adjuvant antibiotic therapy in 20 paediatric patients with mild-to-moderate-CD (10<PCDAI≤37.5; PCDAI, Pediatric Crohn's Disease Activity Index). SOC induction treatment will be Crohn's Disease Exclusion Diet+Partial Enteral Nutrition (CDED+PEN). Relapse-associated microbiome signatures will be evaluated using 16S rRNA gene sequencing and a previously generated Bayesian predictive model (BioMiCo) based on baseline stool. At week 4, patients in remission with relapse-associated signatures (group A) will be randomised to CDED+antibiotics (A2) or CDED+PEN alone (A1). Patients in remission without this signature will continue CDED+PEN alone (B). Patients not in remission will receive CDED+antibiotics regardless of their microbiome signature (C). Subjects in group A2 or C will receive a combination of azithromycin 7.5 mg/kg (weeks 4-8: 5 days/week; weeks 9-12: 3 days/week) with metronidazole 20 mg/kg/day (weeks 4-12). Primary outcomes will assess feasibility of treatment allocation and possible efficacy to sustain remission (PCDAI≤10, no need for reinduction). Exploratory outcomes will include changes in PCDAI, inflammatory markers and patient-reported outcomes. We will additionally explore changes in faecal microbiome taxonomic composition between groups.

ETHICS AND DISSEMINATION

This study was approved by METC-AMC and CCMO (Netherlands) and IWK Health Centre (Canada). The first version of this protocol was approved by North Carolina Children's Hospital (USA), Wolfson Medical Centre (Israel). The FDA (USA), Health Canada and Ministry of Health (Israel) have reviewed and approved the protocol. Results will be published in international peer-reviewed journals and summaries will be provided to the funders and participants.

TRIAL REGISTRATION NUMBER

NCT04186247.

Disturbed Pediatric Gut Microbiome Maturation in the Developmental Origins of Subsequent Chronic Disease

The microbiome is known to play an important role in the development and maintenance of human health. During early childhood the gut microbiome undergoes a rapid evolution, making this developmental window most susceptible to microbial manipulation and, therefore, most vulnerable to environmental stimuli. Such stimuli may induce persistent alterations (or dysbiosis) in microbiome and/or host physiology, thereby resulting in susceptibility to subsequent disease development. This phenomenon is frequently described as "the microbial developmental origins of disease." In this topic of the month, we call attention to the microbial developmental origins of disease by examining the potential for childhood antibiotic exposures and appendectomy (ie, inducers of dysbiosis) to influence the pathogenesis of certain multifactorial, common diseases (eg, celiac disease, inflammatory bowel disease, obesity), especially those with increasing incidence worldwide. We conclude that fully appreciating the critical components in the microbial developmental origins of common chronic disorders is a major task ahead of pediatric gastroenterologists in the 21st century. Such information will be key in working to prevent numerous common and emerging disorders.

Genetic and Epigenetic Etiology of Inflammatory Bowel Disease: An Update

Inflammatory bowel disease (IBD) is a chronic disease with periods of exacerbation and remission of the disease. The etiology of IBD is not fully understood. Many studies point to the presence of genetic, immunological, environmental, and microbiological factors and the interactions between them in the occurrence of IBD. The review looks at genetic factors in the context of both IBD predisposition and pharmacogenetics.

Racial and Ethnic Variation in Presentation, Diagnosis, Treatment, and Outcome of Pediatric Crohn Disease: A Single Center Study

OBJECTIVES

Disparities in health care for racial/ethnic minority children in the United States who are burdened by pediatric Crohn's disease (PCD) are not well understood.

METHODS

A retrospective review of the Texas Children's Hospital ImproveCareNow database from 2007 to 2015 was performed. CD patients with a minimum of 2-year follow-up were included if the onset of symptoms attributable to inflammatory bowel disease was clearly documented. We primarily aimed to identify race and ethnicity associations in diagnostic delay, presentation, treatment, and 2-year outcomes. We also examined early versus late diagnosis (ie, over 6 months from disease onset) associations with these variables unrelated to race/ethnicity.

RESULTS

One hundred and sixty-six PCD patients [57.8% non-Hispanic White (NH-White), 18.1% African American (AA), and 15.7% Hispanic] met selection criteria. Time to diagnosis was shorter in Hispanic patients ( P < 0.01) and they were older at diagnosis than NH-White patients ( P = 0.0164). AA patients (33%, P < 0.01) and Hispanic patients (35%, P < 0.05) had lower rates of granuloma detection than NH-White patients (63%). AA patients had lower rates of steroid-free remission (SFR) at 2 years than NH-White patients ( P < 0.05). Higher ESR and lower hemoglobin levels were associated with early diagnosis ( P < 0.01). Early diagnosis was associated with higher rates of surgery within 2 years of diagnosis ( P < 0.05). Diagnostic fecal calprotectin levels inversely associated with SFR at 2 years ( P < 0.05). Early use of biologics positively, and early use of corticosteroids negatively correlated with 2-year SFR ( P < 0.05).

CONCLUSIONS

Race and ethnicity may influence the diagnosis, treatment, and outcomes of PCD. This recognition presents a nidus toward establishing equity in PCD care.

The Role of the Urban Exposome in the Increasing Global Rates of Pediatric Inflammatory Bowel Disease

Pediatric inflammatory bowel disease (IBD) is becoming increasingly common around the world, rapidly accelerating in regions undergoing rapid economic development. IBD is more common among those living in cities, and the association between the urban environment and IBD incidence is strongest in children. The "urban exposome" is defined as the totality of environmental exposures associated with urban living: air pollution, water contamination, green and blue space, nighttime light, noise, and availability of pre-processed and packaged foods. Investigation of the role of the urban exposome and IBD is in its infancy. Existing research has reached heterogeneous conclusions, and most studies have focused specifically on adult-onset disease and environmental exposures in isolation rather than the interaction between exposures. By better understanding the impact of the urban exposome on pediatric IBD, we can work to minimize these exposures and decrease the future burden of IBD in children.

Impact of the Exposome on the Epigenome in Inflammatory Bowel Disease Patients and Animal Models

Inflammatory bowel diseases (IBD) are chronic inflammatory disorders of the gastrointestinal tract that encompass two main phenotypes, namely Crohn's disease and ulcerative colitis. These conditions occur in genetically predisposed individuals in response to environmental factors. Epigenetics, acting by DNA methylation, post-translational histones modifications or by non-coding RNAs, could explain how the exposome (or all environmental influences over the life course, from conception to death) could influence the gene expression to contribute to intestinal inflammation. We performed a scoping search using Medline to identify all the elements of the exposome that may play a role in intestinal inflammation through epigenetic modifications, as well as the underlying mechanisms. The environmental factors epigenetically influencing the occurrence of intestinal inflammation are the maternal lifestyle (mainly diet, the occurrence of infection during pregnancy and smoking); breastfeeding; microbiota; diet (including a low-fiber diet, high-fat diet and deficiency in micronutrients); smoking habits, vitamin D and drugs (e.g., IBD treatments, antibiotics and probiotics). Influenced by both microbiota and diet, short-chain fatty acids are gut microbiota-derived metabolites resulting from the anaerobic fermentation of non-digestible dietary fibers, playing an epigenetically mediated role in the integrity of the epithelial barrier and in the defense against invading microorganisms. Although the impact of some environmental factors has been identified, the exposome-induced epimutations in IBD remain a largely underexplored field. How these environmental exposures induce epigenetic modifications (in terms of duration, frequency and the timing at which they occur) and how other environmental factors associated with IBD modulate epigenetics deserve to be further investigated.

Maternal Lactobacillus reuteri supplementation shifts the intestinal microbiome in mice and provides protection from experimental colitis in female offspring

The purpose of our experiment was to explore how stochastic (inter-individual variation) gut microbiome composition may link to inflammatory bowel disease (IBD) susceptibility and guide the development of a perinatal preventative probiotic. Dextran sodium sulfate (DSS) was introduced to C57BL/BJ mice to induce acute colitis as a model of IBD. Potentially protective bacteria were identified using a discovery-validation cohort approach toward stochastic DSS susceptibility. Lactobacilli (two different cocktails of L. reuteri and L. johnsonii strains) or control media were supplemented by mouth to dams prior to delivery and during lactation (i.e., perinatal probiotic). The pups were evaluated for DSS susceptibility at young adulthood. Fecal Lactobacillus was increased in the DSS-resistant mice in both the discovery and validation cohorts. Maternal supplementation of female offspring with an L. reuteri cocktail (strains 6798-1, 6798-jm, and 6798-cm) induced progressive microbiome separation and protection against colitis by young adulthood. Maternal supplementation of L. reuteri could confer protection against DSS colitis in young adult female mice. This work is the first to exploit stochastic mammalian microbiome variation to guide microbial therapeutic identification. Our findings underscore neonatal microbiome plasticity and set the stage for the potential development of perinatally deliverable protective probiotics against human IBD.

The Pathogenic Roles of IL-22 in Colitis: Its Transcription Regulation by Musculin in T Helper Subsets and Innate Lymphoid Cells

IL-22 plays a crucial role in promoting inflammation, antimicrobial immunity and tissue repair at barrier surfaces. The role of IL-22 in colitis is still controversial: while IL-22 has a protective effect on gut epithelium in acute injuries, it also enhances colitis in a context-dependent manner. Here, we summarize the Yin and Yang of IL-22 in colitis. Particularly, we emphasize the role of innate lymphoid cells (ILCs) in IL-22 production and regulation. A previously underappreciated transcription factor, Musculin (MSC), has been recently identified to be expressed in not only Th17 cells, but also RORγt+/Id2+ IL-22-producing group 3 ILCs in the gut of naïve mice. We hypothesize that the co-expression and interaction of MSC with the key transcription repressor Id2 in developing lymphoid cells (e.g., in LTi cells) and ILC precursors might fine tune the developmental programs or regulate the plasticity of adaptive Th subset and innate ILCs. The much-elevated expression of IL-22 in MSC-/- ILC3s suggests that MSC may function as: 1) a transcription suppressor for cytokines, particularly for IL-22, and/or 2) a gatekeeper for specific lineages of Th cells and innate ILCs as well. Amelioration of colitis symptoms in MSC-/- mice by IL-22-blocking agent IL-22BP-Fc suggests a counterintuitive pathogenic role of IL-22 in the absence of MSC as a checkpoint. The theory that exuberant production of IL-22 under pathological conditions (e.g., in human inflammatory bowel disease, IBD) may cause epithelial inflammation due to endoplasmic reticulum (ER) stress response is worth further investigation. Rheostatic regulation of IL-22 may be of therapeutic value to restore homeostatic balance and promote intestinal health in human colitis.

Machine Learning Prediction Model for Inflammatory Bowel Disease Based on Laboratory Markers. Working Model in a Discovery Cohort Study

Inflammatory bowel disease (IBD) is a chronic, incurable disease involving the gastrointestinal tract. It is characterized by complex, unclear pathogenesis, increased prevalence worldwide, and a wide spectrum of extraintestinal manifestations and comorbidities. Recognition of IBD remains challenging and delays in disease diagnosis still poses a significant clinical problem as it negatively impacts disease outcome. The main diagnostic tool in IBD continues to be invasive endoscopy. We aimed to create an IBD machine learning prediction model based on routinely performed blood, urine, and fecal tests. Based on historical patients’ data (702 medical records: 319 records from 180 patients with ulcerative colitis (UC) and 383 records from 192 patients with Crohn’s disease (CD)), and using a few simple machine learning classificators, we optimized necessary hyperparameters in order to get reliable few-features prediction models separately for CD and UC. Most robust classificators belonging to the random forest family obtained 97% and 91% mean average precision for CD and UC, respectively. For comparison, the commonly used one-parameter approach based on the C-reactive protein (CRP) level demonstrated only 81% and 61% average precision for CD and UC, respectively. Results of our study suggest that machine learning prediction models based on basic blood, urine, and fecal markers may with high accuracy support the diagnosis of IBD. However, the test requires validation in a prospective cohort.

Emerging Comorbidities in Inflammatory Bowel Disease: Eating Disorders, Alcohol and Narcotics Misuse

Inflammatory bowel disease (IBD) is a chronic and potentially devastating condition of the digestive tract which is exemplified by increasing prevalence worldwide, byzantine pathogenesis with a poorly defined role of the environmental factors, and complex clinical demonstration. As a systemic disease, IBD may progress with a wide spectrum of extraintestinal manifestations (EMs) and comorbidities affecting different organs and systems, from anaemia, undernutrition, and cancer to those which are often neglected like anxiety and depression. Evolving IBD epidemiology and changing environment are reflected by an expanding list of IBD-related comorbidities. In contrast to the well-established role of smoking the connection between alcohol and IBD is still debatable on many levels, from pathogenesis to complications. Furthermore, little is known about narcotics use in IBD patients, even if there are obvious factors that may predispose them to narcotics as well as alcohol misuse. Last but not least, the question arises what is the prevalence of eating disorders in IBD. In our paper, we aimed to discuss the current knowledge on alcohol and drugs misuse and eating disorders as emerging extraintestinal comorbidities in IBD.

Updates and Challenges in Fecal Microbiota Transplantation for Clostridioides difficile Infection in Children

Fecal microbiota transplantation (FMT) is currently the most effective but loosely regulated therapy, for recurrent Clostridioides difficile infection (rCDI) in pediatrics. Over the last 2 years, there have been mounting challenges in the ability to provide FMT to pediatric patients. Firstly, an Food and Drug Administration (FDA) safety alert in 2019 reported transmission of a multidrug resistant organism from FMT donor to recipient resulting in the death of 1 patient. Secondly, the coronavirus disease 2019 (COVID-19) pandemic induced further safety and regulatory challenges. Biotherapeutics are promising and more readily regulated treatment options for rCDI, which may replace FMT in the near future for adults upon regulatory agency approvals. Such approvals, however, are expected to be significantly delayed for children, raising concerns for limited access to effective treatment for children with rCDI. In this commentary, we discuss the recent challenges and future directions of FMT and microbial therapeutics in children with rCDI.

Antibiotics in pediatric inflammatory bowel diseases: a systematic review

Introduction: Current therapies in pediatric Inflammatory Bowel Diseases (IBD) target the immune system and often fail to sustain long-term remission. There is a high need for development of alternative treatment strategies such as antibiotics in pediatric IBD.Areas covered: This study systematically assessed efficacy and safety of antibiotics in pediatric IBD. CENTRAL, EMBASE, and Medline were searched for Randomized Controlled Trials (RCTs). Quality assessment was conducted with the Cochrane risk-of-bias tool.Expert opinion: Two RCTs (n = 101, 4.4-18 years, 43% male) were included. Both studies had overall low risk of bias. In mild-to-moderate Crohn's disease, azithromycin+metronidazole (AZ+MET) (n = 35) compared to metronidazole (MET) alone (n = 38) did not induce a significantly different response (PCDAI drop ≥12.5 or remission) (p = 0.07). For induction of remission (PCDAI≤10), AZ+MET was more effective than MET (p = 0.025). In Acute Severe Colitis, mean 5-day-PUCAI was significantly lower in the antibiotic (vancomycin, amoxicillin, metronidazole, doxycycline)+intravenous-corticosteroids group (AB+IVCS) (n = 16) compared to IVCS alone (n=12) (p = 0.037), whereas remission (PUCAI<10) did not differ (p = 0.61). No significant drug-related adverse events were reported. Results of this systematic review of antibiotic use highlight the lack of evidence in pediatric IBD. More evidence is needed before widespread implementation in daily practice.

Acute Experimental Barrier Injury Triggers Ulcerative Colitis-Specific Innate Hyperresponsiveness and Ulcerative Colitis-Type Microbiome Changes in Humans

BACKGROUND AND AIMS

The trigger hypothesis opens the possibility of anti-flare initiation therapies by stating that ulcerative colitis (UC) flares originate from inadequate responses to acute mucosal injuries. However, experimental evidence is restricted by a limited use of suitable human models. We thus aimed to investigate the acute mucosal barrier injury responses in humans with and without UC using an experimental injury model.

METHODS

A standardized mucosal break was inflicted in the sigmoid colon of 19 patients with UC in endoscopic and histological remission and 20 control subjects. Postinjury responses were assessed repeatedly by high-resolution imaging and sampling to perform Geboes scoring, RNA sequencing, and injury niche microbiota 16S ribosomal RNA gene sequencing.

RESULTS

UC patients had more severe endoscopic postinjury inflammation than did control subjects (P < .01), an elevated modified Geboes score (P < .05), a rapid induction of innate response gene sets (P < .05) and antimicrobial peptides (P < .01), and engagement of neutrophils (P < .01). Innate lymphoid cell type 3 (ILC3) markers were increased preinjury (P < .01), and ILC3 activating cytokines were highly induced postinjury, resulting in an increase in ILC3-type cytokine interleukin-17A. Across groups, the postinjury mucosal microbiome had higher bacterial load (P < .0001) and lower α-diversity (P < .05).

CONCLUSIONS

UC patients in remission respond to mucosal breaks by an innate hyperresponse engaging resident regulatory ILC3s and a subsequent adaptive activation. The postinjury inflammatory bowel disease-like microbiota diversity decrease is irrespective of diagnosis, suggesting that the dysbiosis is secondary to host injury responses. We provide a model for the study of flare initiation in the search for antitrigger-directed therapies.

An Immunologic Compatibility Testing Was Not Useful for Donor Selection in Fecal Microbiota Transplantation for Ulcerative Colitis

Fecal microbiota transplantation (FMT) is an effective procedure against Clostridioides difficile infection (CDI), with promising but still suboptimal performance in other diseases, such as ulcerative colitis (UC). The recipient’s mucosal immune response against the donor’s microbiota could be relevant factor in the effectiveness of FMT. Our aim was to design and validate an individualized immune-based test to optimize the fecal donor selection for FMT. First, we performed an in vitro validation of the test by co-culturing lymphocytes obtained from the small intestine mucosa of organ donor cadavers (n=7) and microbe-associated molecular patterns (MAMPs) obtained from the feces of 19 healthy donors. The inflammatory response was determined by interleukin supernatant quantification using the Cytometric Bead Array kit (B&D). We then conducted a clinical pilot study with 4 patients with UC using immunocompetent cells extracted from rectal biopsies and MAMPs from 3 donor candidates. We employed the test results to guide donor selection for FMT, which was performed by colonoscopy followed by 4 booster instillations by enema in the following month. The microbiome engraftment was assessed by 16S rDNA massive sequencing in feces, and the patients were clinically followed-up for 16 weeks. The results demonstrated that IL-6, IL-8, and IL-1ß were the most variable markers, although we observed a general tolerance to the microbial insults. Clinical and colonoscopy remission of the patients with UC was not achieved after 16 weeks, although FMT provoked enrichment of the Bacteroidota phylum and Prevotella genus, with a decrease in the Actinobacteriota phylum and Agathobacter genus. The most relevant result was the lack of Akkermansia engraftment in UC. In summary, the clinical success of FMT in patients with UC appears not to be influenced by donor selection based on the explored recipient’s local immunological response to FMT, suggesting that this approach would not be valid for FMT fecal donor optimization in such patients.

Machine Learning Classification of Inflammatory Bowel Disease in Children Based on a Large Real-World Pediatric Cohort CEDATA-GPGE® Registry

Introduction: The rising incidence of pediatric inflammatory bowel diseases (PIBD) facilitates the need for new methods of improving diagnosis latency, quality of care and documentation. Machine learning models have shown to be applicable to classifying PIBD when using histological data or extensive serology. This study aims to evaluate the performance of algorithms based on promptly available data more suited to clinical applications.

Methods: Data of inflammatory locations of the bowels from initial and follow-up visitations is extracted from the CEDATA-GPGE registry and two follow-up sets are split off containing only input from 2017 and 2018. Pre-processing excludes patients in remission and encodes the categorical data numerically. For classification of PIBD diagnosis, a support vector machine (SVM), a random forest algorithm (RF), extreme gradient boosting (XGBoost), a dense neural network (DNN) and a convolutional neural network (CNN) are employed. As best performer, a convolutional neural network is further improved using grid optimization.

Results: The achieved accuracy of the optimized neural network reaches up to 90.57% on data inserted into the registry in 2018. Less performant methods reach 88.78% for the DNN down to 83.94% for the XGBoost. The accuracy of prediction for the 2018 follow-up dataset is higher than those for older datasets. Neural networks yield a higher standard deviation with 3.45 for the CNN compared to 0.83–0.86 of the support vector machine and ensemble methods.

Discussion: The displayed accuracy of the convolutional neural network proofs the viability of machine learning classification in PIBD diagnostics using only timely available data.