Interrogation of the mammalian gut-brain axis using LC-MS/MS-based targeted metabolomics with in vitro bacterial and organoid cultures and in vivo gnotobiotic mouse models.

Interest in the communication between the gastrointestinal tract and central nervous system, known as the gut-brain axis, has prompted the development of quantitative analytical platforms to analyze microbe- and host-derived signals. This protocol enables investigations into connections between microbial colonization and intestinal and brain neurotransmitters and contains strategies for the comprehensive evaluation of metabolites in in vitro (organoids) and in vivo mouse model systems. Here we present an optimized workflow that includes procedures for preparing these gut-brain axis model systems: (stage 1) growth of microbes in defined media; (stage 2) microinjection of intestinal organoids; and (stage 3) generation of animal models including germ-free (no microbes), specific-pathogen-free (complete gut microbiota) and specific-pathogen-free re-conventionalized (germ-free mice associated with a complete gut microbiota from a specific-pathogen-free mouse), and Bifidobacterium dentium and Bacteroides ovatus mono-associated mice (germ-free mice colonized with a single gut microbe). We describe targeted liquid chromatography-tandem mass spectrometry-based metabolomics methods for analyzing microbially derived short-chain fatty acids and neurotransmitters from these samples. Unlike other protocols that commonly examine only stool samples, this protocol includes bacterial cultures, organoid cultures and in vivo samples, in addition to monitoring the metabolite content of stool samples. The incorporation of three experimental models (microbes, organoids and animals) enhances the impact of this protocol. The protocol requires 3 weeks of murine colonization with microbes and ~1-2 weeks for liquid chromatography-tandem mass spectrometry-based instrumental and quantitative analysis, and sample post-processing and normalization.

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.

National Trends in Hospitalization, Surgical Resection, and Comorbidities in Pediatric Inflammatory Bowel Disease in the United States, 2002-2015.

Background and Objective: Therapeutic options for pediatric inflammatory bowel disease (PIBD) have dramatically changed over the last 20 years. However, the impact of modern medical management on PIBD outcomes remains unclear. We aimed to fill this gap in the literature by using a large, validated, national database, to study the change in hospitalization rates, surgical rates, and postoperative complications in PIBD over the last decade. Methods: The National Inpatient Sample (NIS) Database and ICD-9-CM codes were utilized to identify inpatient admissions with a primary or secondary diagnosis of pediatric Crohn's disease (CD) or ulcerative colitis (UC) from 2002-2015. Trends in hospitalizations, comorbidities (including malnutrition and weight loss), surgical procedures, and postoperative complications were examined using joinpoint regression analysis, a statistical modeling approach to evaluate the extent to which the rate of a condition changes over time. Results: There were 119,282 admissions for PIBD during the study period. The annual incidence of hospitalization increased significantly over time for both CD (average annual percent change [AAPC] 6.0%) and UC (AAPC 7.2%). The rate of intestinal resection decreased in CD patients (AAPC -6.4%) while postoperative complications remained unchanged. However, comorbidities increased significantly in CD patients (AAPC 6.8%). For pediatric UC patients, postoperative complications (AAPC 6.7%), and comorbidities (AAPC 10.2%) increased significantly over time while intestinal resection rates remained stable. Intestinal resection rate in pediatric CD has decreased over time, but not in pediatric UC. Conclusion and Global Health Implications: Annual incidence of hospitalization and comorbidities continue to increase in PIBD. Intestinal resection rate in pediatric CD has decreased over time, but not in pediatric UC. Our findings emphasize the critical need for prevention and novel therapeutic options for this vulnerable patient population.

Bacteroides ovatus colonization influences the abundance of intestinal short chain fatty acids and neurotransmitters.

Gut microbes can synthesize multiple neuro-active metabolites. We profiled neuro-active compounds produced by the gut commensal Bacteroides ovatus in vitro and in vivo by LC-MS/MS. We found that B. ovatus generates acetic acid, propionic acid, isobutyric acid, and isovaleric acid. In vitro, B. ovatus consumed tryptophan and glutamate and synthesized the neuro-active compounds glutamine and GABA. Consistent with our LC-MS/MS-based in vitro data, we observed elevated levels of acetic acid, propionic acid, isobutyric acid, and isovaleric acid in the intestines of B. ovatus mono-associated mice compared with germ-free controls. B. ovatus mono-association also increased the concentrations of intestinal GABA and decreased the concentrations of tryptophan and glutamine compared with germ-free controls. Computational network analysis revealed unique links between SCFAs, neuro-active compounds, and colonization status. These results highlight connections between microbial colonization and intestinal neurotransmitter concentrations, suggesting that B. ovatus selectively influences the presence of intestinal neurotransmitters.

Trends and Disparities in Pediatric Nonalcoholic Fatty Liver Disease-Associated Hospitalizations in the United States.

OBJECTIVE: Non-alcoholic fatty liver disease (NAFLD) represents a spectrum of disease characterized by accumulation of fat in the liver and is associated with co-morbidities linked to metabolic syndrome. The prevalence of NAFLD in children has increased in the United States over time and with marked racial differences observed in geographically limited studies. This study aims to provide a current, nation-wide analysis of temporal trends of pediatric NAFLD-related hospitalizations and associated co-morbidities as well as assess for racial/ethnic disparities. METHODS: A cross-sectional study was conducted using the National Inpatient Sample (NIS) from 2004 to 2018 and included NAFLD-associated hospitalizations of children ages 0-17 years of age based on ICD-9/10 diagnosis codes. Rates and patient characteristics analyzed via descriptive statistics and associations via survey logistic regression. Temporal trends assessed via joinpoint regression. RESULTS: There was an overall increase in pediatric NAFLD-associated hospitalizations with an average annual percent change (AAPC) of 6.6 with highest rates among Hispanic patients (AAPC = 11.1) compared to NH-White (AAPC = 4.1) and NH-Black (AAPC = 2.1). Analysis of race/ethnicity and NAFLD hospitalization showed an increased association in Hispanic patients (odds ratio [OR] = 1.64, 95% confidence interval [CI] = 1.51-1.77) and a decreased association in non-Hispanic (NH)-Black patients (OR = 0.49, 95% CI = 0.45-0.54) when compared to NH-White patients. CONCLUSION: Utilizing a nation-wide database we demonstrated significant increases in NAFLD-associated hospitalizations with highest prevalence and rates seen in Hispanic patients. In addition, sex and comorbidities showed notable correlation to these hospitalization rates displaying the need for further studies on these relationships and highlights the potential for interventions aimed at high-risk groups.

Fecal Microbiota Transplantation Commonly Failed in Children With Co-Morbidities.

OBJECTIVES: Fecal microbiota transplantation (FMT) is arguably the most effective treatment for recurrent Clostridioides difficile infection (rCDI). Clinical reports on pediatric FMT have not systematically evaluated microbiome restoration in patients with co-morbidities. Here, we determined whether FMT recipient age and underlying co-morbidity influenced clinical outcomes and microbiome restoration when treated from shared fecal donor sources. METHODS: Eighteen rCDI patients participating in a single-center, open-label prospective cohort study received fecal preparation from a self-designated (single case) or two universal donors. Twelve age-matched healthy children and four pediatric ulcerative colitis (UC) cases from an independent serial FMT trial, but with a shared fecal donor were examined as controls for microbiome restoration using 16S rRNA gene sequencing of longitudinal fecal specimens. RESULTS: FMT was significantly more effective in rCDI recipients without underlying chronic co-morbidities where fecal microbiome composition in post-transplant responders was restored to levels of healthy children. Microbiome reconstitution was not associated with symptomatic resolution in some rCDI patients who had co-morbidities. Significant elevation in Bacteroidaceae, Bifidobacteriaceae, Lachnospiraceae, Ruminococcaceae, and Erysipelotrichaceae was consistently observed in pediatric rCDI responders, while Enterobacteriaceae decreased, correlating with augmented complex carbohydrate degradation capacity. CONCLUSION: Recipient background disease was a significant risk factor influencing FMT outcomes. Special attention should be taken when considering FMT for pediatric rCDI patients with underlying co-morbidities.

Unraveling the Metabolic Requirements of the Gut Commensal Bacteroides ovatus.

Background: Bacteroidetes are the most common bacterial phylum in the mammalian intestine and the effects of several Bacteroides spp. on multiple facets of host physiology have been previously described. Of the Bacteroides spp., Bacteroides ovatus has recently garnered attention due to its beneficial effects in the context of intestinal inflammation. In this study, we aimed to examine model host intestinal physiological conditions and dietary modifications to characterize their effects on B. ovatus growth. Methods and Results: Using Biolog phenotypic microarrays, we evaluated 62 primary carbon sources and determined that B. ovatus ATCC 8384 can use the following carbohydrates as primary carbon sources: 10 disaccharides, 4 trisaccharides, 4 polysaccharides, 4 polymers, 3 L-linked sugars, 6 D-linked sugars, 5 amino-sugars, 6 alcohol sugars, and 15 organic acids. Proteomic profiling of B. ovatus bacteria revealed that a significant portion of the B. ovatus proteome contains proteins important for metabolism. Among the proteins, we found glycosyl hydrolase (GH) familes GH2, GH5, GH20, GH 43, GH88, GH92, and GH95. We also identified multiple proteins with antioxidant properties and reasoned that these proteins may support B. ovatus growth in the GI tract. Upon further testing, we showed that B. ovatus grew robustly in various pH, osmolarity, bile, ethanol, and H2O2 concentrations; indicating that B. ovatus is a well-adapted gut microbe. Conclusion: Taken together, we have demonstrated that key host and diet-derived changes in the intestinal environment influence B. ovatus growth. These data provide the framework for future work toward understanding how diet and lifestyle interventions may promote a beneficial environment for B. ovatus growth.

High Seroconversion Rate Against Severe Acute Respiratory Syndrome Coronavirus 2 in Symptomatic Pediatric Inflammatory Bowel Disease Patients.

ABSTRACT: Understanding coronavirus disease 2019 (COVID-19) in pediatric inflammatory bowel disease (PIBD) is important. We describe a single-center cohort of COVID-19 PIBD patients where seroconversion against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was examined.Immunosuppressed PIBD patients at Texas Children's Hospital who tested positive for SARS-CoV-2 by nasopharyngeal reverse transcriptase polymerase chain reaction were included in the study. The clinical course of IBD, concurrent medications, COVID-19 related symptoms, SARS-CoV-2 testing date, and SARS-CoV-2 immunoglobulin G (IgG) antibody testing date and result were examined. Of 14 SARS-CoV-2 positive PIBD patients, 12 were tested for qualitative anti-SARS-CoV-2 IgG (seven with transient COVID-19 symptoms, five asymptomatic). All symptomatic (7/7) and 60% of asymptomatic (3/5) patients seroconverted. No patients required hospitalization attributed to COVID-19.High rates of COVID-19 seroconversion occurred in immunosuppressed and symptomatic PIBD patients. More research to evaluate the significance of COVID-19 seroconversion is needed.

Bifidobacterium dentium-derived y-glutamylcysteine suppresses ER-mediated goblet cell stress and reduces TNBS-driven colonic inflammation.

Endoplasmic reticulum (ER) stress compromises the secretion of MUC2 from goblet cells and has been linked with inflammatory bowel disease (IBD). Although Bifidobacterium can beneficially modulate mucin production, little work has been done investigating the effects of Bifidobacterium on goblet cell ER stress. We hypothesized that secreted factors from Bifidobacterium dentium downregulate ER stress genes and modulates the unfolded protein response (UPR) to promote MUC2 secretion. We identified by mass spectrometry that B. dentium secretes the antioxidant γ-glutamylcysteine, which we speculate dampens ER stress-mediated ROS and minimizes ER stress phenotypes. B. dentium cell-free supernatant and γ-glutamylcysteine were taken up by human colonic T84 cells, increased glutathione levels, and reduced ROS generated by the ER-stressors thapsigargin and tunicamycin. Moreover, B. dentium supernatant and γ-glutamylcysteine were able to suppress NF-kB activation and IL-8 secretion. We found that B. dentium supernatant, γ-glutamylcysteine, and the positive control IL-10 attenuated the induction of UPR genes GRP78, CHOP, and sXBP1. To examine ER stress in vivo, we first examined mono-association of B. dentium in germ-free mice which increased MUC2 and IL-10 levels compared to germ-free controls. However, no changes were observed in ER stress-related genes, indicating that B. dentium can promote mucus secretion without inducing ER stress. In a TNBS-mediated ER stress model, we observed increased levels of UPR genes and pro-inflammatory cytokines in TNBS treated mice, which were reduced with addition of live B. dentium or γ-glutamylcysteine. We also observed increased colonic and serum levels of IL-10 in B. dentium- and γ-glutamylcysteine-treated mice compared to vehicle control. Immunostaining revealed retention of goblet cells and mucus secretion in both B. dentium- and γ-glutamylcysteine-treated animals. Collectively, these data demonstrate positive modulation of the UPR and MUC2 production by B. dentium-secreted compounds.

Bacteroides ovatus Promotes IL-22 Production and Reduces Trinitrobenzene Sulfonic Acid-Driven Colonic Inflammation.

The intestinal microbiota influences the development and function of the mucosal immune system. However, the exact mechanisms by which commensal microbes modulate immunity is not clear. We previously demonstrated that commensal Bacteroides ovatus ATCC 8384 reduces mucosal inflammation. Herein, we aimed to identify immunomodulatory pathways employed by B. ovatus. In germ-free mice, mono-association with B. ovatus shifted the CD11b+/CD11c+ and CD103+/CD11c+ dendritic cell populations. Because indole compounds are known to modulate dendritic cells, B. ovatus cell-free supernatant was screened for tryptophan metabolites by liquid chromatography-tandem mass spectrometry and larger quantities of indole-3-acetic acid were detected. Analysis of cecal and fecal samples from germ-free and B. ovatus mono-associated mice confirmed that B. ovatus could elevate indole-3-acetic acid concentrations in vivo. Indole metabolites have previously been shown to stimulate immune cells to secrete the reparative cytokine IL-22. Addition of B. ovatus cell-free supernatant to immature bone marrow-derived dendritic cells stimulated IL-22 secretion. The ability of IL-22 to drive repair in the intestinal epithelium was confirmed using a physiologically relevant human intestinal enteroid model. Finally, B. ovatus shifted the immune cell populations in trinitrobenzene sulfonic acid-treated mice and up-regulated colonic IL-22 expression, effects that correlated with decreased inflammation. Our data suggest that B. ovatus-produced indole-3-acetic acid promotes IL-22 production by immune cells, yielding beneficial effects on colitis.

Immunomodulation of dendritic cells by Lactobacillus reuteri surface components and metabolites.

BACKGROUND: Lactic acid bacteria are commensal members of the gut microbiota and are postulated to promote host health. Secreted factors and cell surface components from Lactobacillus species have been shown to modulate the host immune system. However, the precise role of L. reuteri secreted factors and surface proteins in influencing dendritic cells (DCs) remains uncharacterized. HYPOTHESIS: We hypothesize that L. reuteri secreted factors will promote DC maturation, skewing cells toward an anti-inflammatory phenotype. In acute colitis, we speculate that L. reuteri promotes IL-10 and dampens pro-inflammatory cytokine production, thereby improving colitis. METHODS & RESULTS: Mouse bone marrow-derived DCs were differentiated into immature dendritic cells (iDCs) via IL-4 and GM-CSF stimulation. iDCs exposed to L. reuteri secreted factors or UV-irradiated bacteria exhibited greater expression of DC maturation markers CD83 and CD86 by flow cytometry. Additionally, L. reuteri stimulated DCs exhibited phenotypic maturation as denoted by cytokine production, including anti-inflammatory IL-10. Using mouse colonic organoids, we found that the microinjection of L. reuteri secreted metabolites and UV-irradiated bacteria was able to promote IL-10 production by DCs, indicating potential epithelial-immune cross-talk. In a TNBS-model of acute colitis, L. reuteri administration significantly improved histological scoring, colonic cytokine mRNA, serum cytokines, and bolstered IL-10 production. CONCLUSIONS: Overall these data demonstrate that both L. reuteri secreted factors and its bacterial components are able to promote DC maturation. This work points to the specific role of L. reuteri in modulating intestinal DCs. NEW & NOTEWORTHY: Lactobacillus reuteri colonizes the mammalian gastrointestinal tract and exerts beneficial effects on host health. However, the mechanisms behind these effects have not been fully explored. In this article, we identified that L. reuteri ATTC PTA 6475 metabolites and surface components promote dendritic cell maturation and IL-10 production. In acute colitis, we also demonstrate that L. reuteri can promote IL-10 and suppress inflammation. These findings may represent a crucial mechanism for maintaining intestinal immune homeostasis.

Human-Derived Bifidobacterium dentium Modulates the Mammalian Serotonergic System and Gut-Brain Axis.

BACKGROUND & AIMS: The human gut microbiota can regulate production of serotonin (5-hydroxytryptamine [5-HT]) from enterochromaffin cells. However, the mechanisms underlying microbial-induced serotonin signaling are not well understood. METHODS: Adult germ-free mice were treated with sterile media, live Bifidobacterium dentium, heat-killed B dentium, or live Bacteroides ovatus. Mouse and human enteroids were used to assess the effects of B dentium metabolites on 5-HT release from enterochromaffin cells. In vitro and in vivo short-chain fatty acids and 5-HT levels were assessed by mass spectrometry. Expression of tryptophan hydroxylase, short-chain fatty acid receptor free fatty acid receptor 2, 5-HT receptors, and the 5-HT re-uptake transporter (serotonin transporter) were assessed by quantitative polymerase chain reaction and immunostaining. RNA in situ hybridization assessed 5-HT-receptor expression in the brain, and 5-HT-receptor-dependent behavior was evaluated using the marble burying test. RESULTS: B dentium mono-associated mice showed increased fecal acetate. This finding corresponded with increased intestinal 5-HT concentrations and increased expression of 5-HT receptors 2a, 4, and serotonin transporter. These effects were absent in B ovatus-treated mice. Application of acetate and B dentium-secreted products stimulated 5-HT release in mouse and human enteroids. In situ hybridization of brain tissue also showed significantly increased hippocampal expression of 5-HT-receptor 2a in B dentium-treated mice relative to germ-free controls. Functionally, B dentium colonization normalized species-typical repetitive and anxiety-like behaviors previously shown to be linked to 5-HT-receptor 2a. CONCLUSIONS: These data suggest that B dentium, and the bacterial metabolite acetate, are capable of regulating key components of the serotonergic system in multiple host tissues, and are associated with a functional change in adult behavior.

Progression to colectomy in the era of biologics: A single center experience with pediatric ulcerative colitis.

BACKGROUND/PURPOSE: Clinical outcomes in pediatric ulcerative colitis (UC) in the era of biologic agents are poorly defined. We aimed to describe risk factors for colectomy in pediatric UC in the era of infliximab therapy. METHODS: We reviewed 217 pediatric patients at Texas Children's Hospital with newly diagnosed UC between 2003 and 2015; 117 had a minimum of 5 years of follow-up. Extent of disease at diagnosis, medication exposure, the presence of extraintestinal manifestations (EIMs), and need for surgery were noted. RESULTS: Average length of follow up was 5.02 ±â€¯2.27 years. Forty-two percent presented with pancolitis. Infliximab was used in 39%, immunomodulators in 65%, and steroids in 89% of patients. EIMs occurred in 24.9% of patients. The cumulative rate of colectomy was 12.9% at 5 years. Children presenting as E2 (Paris Classification) and children prescribed oral steroid monotherapy at diagnosis progressed to surgery faster than any other group. Of the children who received infliximab, females and children less than 5 years old were less likely to respond to therapy. CONCLUSIONS: The natural course of pediatric UC remains aggressive despite the addition of infliximab to the standard of care and suggests a need for early aggressive clinical intervention. LEVEL-OF-EVIDENCE RATING: Level IV.

Diagnostic delay and colectomy risk in pediatric ulcerative colitis.

BACKGROUND/PURPOSE: Diagnostic delay or time to diagnosis, and its relationship with colectomy risk has been studied in adult Inflammatory Bowel Disease (IBD), but rarely in pediatric IBD (PIBD), especially pediatric ulcerative colitis (P-UC), which often has a more severe course than adult UC. This study compared the relationship between diagnostic delay and colectomy in P-UC. METHODS: The medical records of P-UC patients, ages <18 years, diagnosed at Texas Children's Hospital from 2012 to 2018 were examined. We identified 106 P-UC patients, where the onset of symptoms of IBD (i.e. fever, diarrhea, blood in stool, weight loss, abdominal pain) could be clearly identified. RESULTS: Twenty (20 = 18.9%) patients progressed to colectomy, and 86 did not. There was no significant difference in diagnostic delay between the patients undergoing colectomy with UC (C-UC) and those with no colectomy (NC-UC) (p = 0.2192). The median (C-UC = 7.1 weeks; NC-UC = 11.9 weeks) and mean (C-UC = 16.5 weeks±4.7; NC-UC = 20.1 ±â€¯2.6) diagnostic delay actually tended to be shorter in C-UC compared to NC-UC. Fecal calprotectin levels were significantly higher (p = 0.0228) in C-UC than NC-UC patients at diagnosis. CONCLUSIONS: Shorter time to diagnosis may reflect disease severity at the time of disease onset and also a more aggressive subsequent course of P-UC. The significantly higher level of fecal calprotectin in the C-UC patients at diagnosis provided biologic/biochemical support for our conclusion. LEVELS OF EVIDENCE: Prognosis study, Level III evidence.

Fecal microbiota transplantation in a toddler after heart transplant was a safe and effective treatment for recurrent Clostridiodes difficile infection: A case report.

Pediatric recipients of SOT have a significantly increased risk of Clostridiodes (formerly Clostridium) difficile infection (CDI), which is associated with adverse outcomes after SOT. Alterations to the intestinal microbiota community structure increase the risk of CDI. FMT is a safe and effective treatment for recurrent CDI in immunocompetent children and adults. While there are increasing data that FMT in immunosuppressed patients is safe and effective without increased risk of infection, data regarding safety and efficacy of FMT in children after SOT are limited. To our knowledge, we report the youngest immunocompromised patient to undergo FMT and the third overall case of FMT in a child after HTx. Our patient presented with five episodes of rCDI in 6 months, and 16S rRNA genetic analysis revealed significant loss of overall microbiota community structure and diversity prior to FMT compared with a donor and a healthy, age-matched control. After FMT, marked and prolonged (at least 16 months) shifts in the recipient microbiota community structure and diversity were evident, approaching that of donor and healthy, age-matched control. FMT was well tolerated, restored microbial diversity without any graft or transplant complications, and prevented further rCDI episodes after more than 4 years of follow-up.

Bacteroides ovatus ATCC 8483 monotherapy is superior to traditional fecal transplant and multi-strain bacteriotherapy in a murine colitis model.

Background and aims: Bacteriotherapy aimed at addressing dysbiosis may be therapeutic for Inflammatory Bowel Diseases (IBDs). We sought to determine if defined Bacteroides-based bacteriotherapy could be an effective and consistent alternative to fecal microbiota transplantation (FMT) in a murine model of IBD. Methods: We induced experimental colitis in 8- 12-week-old C57BL/6 mice using 2-3% dextran sodium sulfate. Mice were simultaneously treated by oral gavage with a triple-Bacteroides cocktail, individual Bacteroides strains, FMT using stool from healthy donor mice, or their own stool as a control. Survival, weight loss and markers of inflammation (histology, serum amyloid A, cytokine production) were correlated to 16S rRNA gene profiling of fecal and mucosal microbiomes. Results: Triple-Bacteroides combination therapy was more protective against weight loss and mortality than traditional FMT therapy. B. ovatus ATCC8483 was more effective than any individual strain, or a combination of strains, in preventing weight loss, decreasing histological damage, dampening inflammatory response, and stimulating epithelial recovery. Irrespective of the treatment group, overall Bacteroides abundance associated with treatment success and decreased cytokine production while the presence of Akkermansia correlated with treatment failure. However, the therapeutic benefit associated with high Bacteroides abundance was negated in the presence of Streptococcus. Conclusions: Bacteroides ovatus monotherapy was more consistent and effective than traditional FMT at ameliorating colitis and stimulating epithelial recovery in a murine model of IBD. Given the tolerability of Bacteroides ovatus ATCC 8483 in an active, on-going human study, this therapy may be repurposed for the management of IBD in a clinically expedient timeline.

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

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

Granulomatous Upper Gastrointestinal Inflammation in Pediatric Ulcerative Colitis.

OBJECTIVES: Differentiating ulcerative colitis (UC) and Crohn disease (CD) can be clinically challenging, especially in children. Granulomatous inflammation has traditionally been attributed to CD. Crypt-associated giant cells and granulomas, however, have been observed in colonic biopsies of patients with UC. This phenomenon has not been described in the upper gastrointestinal (UGI) tract with UC. METHODS: Seven pediatric patients with UC with granulomatous UGI (gUGI) lesions were identified. Diagnosis of UC was based on symptoms, clinical course, laboratory results, imaging, and endoscopy. We compared the gUGI patients to a large cohort of pediatric patients with UC (n = 149). RESULTS: All fully evaluated cases were associated with bloody diarrhea and moderate to severe pancolitis. Gastric and/or duodenal biopsies demonstrated giant cells or granulomas near gland destruction. Small bowel imaging did not reveal any involvement. The majority of cases responded to standard medical therapies, except for 2 patients (28.6%) who required total colectomy. Acute severe, refractory colitis (ie, colectomy within 1 month of presentation) was significantly more common in the gUGI group than the large pediatric UC group (28.6% vs 1.3%, Fisher exact P = 0.01). CONCLUSIONS: This is the first report of pediatric UC-associated granulomatous inflammation in the UGI tract. We speculate that these lesions represent extracolonic manifestations of intense colonic disease. These atypical findings expand the diagnostic considerations that should be incorporated during the differentiation between UC and CD in the pediatric age group.

Inflammatory Bowel Disease and Immune Thrombocytopenic Purpura: Combined Immune Dysregulation in an Adolescent.

Concomitant inflammatory bowel disease (IBD) and immune thrombocytopenic purpura (ITP) is a rare phenomenon. A shared immunologic pathway leading to mucosal inflammation and platelet destruction has been proposed. We report a case of a 14-year-old male who presented with abdominal pain, hematochezia, weight loss, and thrombocytopenia. Endoscopic and hematologic evaluations led to the diagnosis of ulcerative colitis (UC) and ITP, respectively. Initial treatment of his UC resulted in improvement in both gastrointestinal symptoms and platelet count. Management of this case, however, was complicated by inconsistent correlation between UC symptoms and platelet count throughout his clinical course. The co-occurrence of IBD and ITP is an important entity, albeit rare, which needs to be considered when evaluating a patient with hematochezia and thrombocytopenia.