Pre-operative visceral adipose tissue radiodensity is a potentially novel prognostic biomarker for early endoscopic post-operative recurrence in Crohn's disease

BACKGROUND

Evidence suggests inflammatory mesenteric fat is involved in post-operative recurrence (POR) of Crohn's disease (CD). However, its prognostic value is uncertain, in part, due to difficulties studying it non-invasively.

AIM

To evaluate the prognostic value of pre-operative radiographic mesenteric parameters for early endoscopic POR (ePOR).

METHODS

We conducted a retrospective cohort study of CD subjects ≥ 12 years who underwent ileocecal or small bowel resection between 1/1/2007 to 12/31/2021 with computerized tomography abdomen/pelvis ≤ 6 months pre-operatively and underwent ileocolonoscopy ≤ 15 months post-operatively. Visceral adipose tissue (VAT) volume (cm3), ratio of VAT:subcutaneous adipose tissue (SAT) volume, VAT radiodensity, and ratio of VAT:SAT radiodensity were generated semiautomatically. Mesenteric lymphadenopathy (LAD, largest lymph node > 10 mm) and severe vasa recta (VR) engorgement (diameter of the VR supplying diseased bowel ≥ 2 × VR supplying healthy bowel) were derived manually. The primary outcome was early ePOR (Rutgeert's score ≥ i2 on first endoscopy ≤ 15 months post-operatively) and the secondary outcome was ePOR severity (Rutgeert's score i0-4). Regression analyses were performed adjusting for demographic and disease-related characteristics to calculate adjusted odds ratio (aOR) and 95% confidence interval (CI).

RESULTS

Of the 139 subjects included, 45% of subjects developed early ePOR (n = 63). VAT radiodensity (aOR 0.59, 95%CI: 0.38-0.90) and VAT:SAT radiodensity (aOR 8.54, 95%CI: 1.48-49.28) were associated with early ePOR, whereas, VAT volume (aOR 1.23, 95%CI: 0.78-1.95), VAT:SAT volume (aOR 0.80, 95%CI: 0.53-1.20), severe VR engorgement (aOR 1.53, 95%CI: 0.64-3.66), and mesenteric LAD (aOR 1.59, 95%CI: 0.67-3.79) were not. Similar results were observed for severity of ePOR.

CONCLUSION

VAT radiodensity is potentially a novel non-invasive prognostic imaging marker to help risk stratify CD patients for POR.

Comprehensive Association Analyses of Extraintestinal Manifestations in Inflammatory Bowel Disease

BACKGROUND & AIMS

Patients with inflammatory bowel disease (IBD) frequently develop extraintestinal manifestations (EIMs) that contribute substantially to morbidity. We assembled the largest multicohort data set to date to investigate the clinical, serologic, and genetic factors associated with EIM complications in IBD.

METHODS

Data were available in 12,083 unrelated European ancestry IBD cases with presence or absence of EIMs (eg, ankylosing spondylitis [ankylosing spondylitis and sacroiliitis], primary sclerosing cholangitis [PSC], peripheral arthritis, and skin and ocular manifestations) across 4 cohorts (Cedars-Sinai Medical Center, National Institute for Diabetes and Digestive and Kidney Diseases IBD Genetics Consortium, Sinai Helmsley Alliance for Research Excellence Consortium, and Risk Stratification and Identification of Immunogenetic and Microbial Markers of Rapid Disease Progression in Children with Crohn's Disease cohort). Clinical and serologic parameters were analyzed by means of univariable and multivariable regression analyses using a mixed-effects model. Within-case logistic regression was performed to assess genetic associations.

RESULTS

Most EIMs occurred more commonly in female subjects (overall EIM: P = 9.0E-05, odds ratio [OR], 1.2; 95% CI, 1.1-1.4), with CD (especially colonic disease location; P = 9.8E-09, OR, 1.7; 95% CI, 1.4-2.0), and in subjects who required surgery (both CD and UC; P = 3.6E-19, OR, 1.7; 95% CI, 1.5-1.9). Smoking increased risk of EIMs except for PSC, where there was a "protective" effect. Multiple serologic associations were observed, including with PSC (IgG and IgA, perinuclear anti-nuclear cytoplasmic antibody; anti-Saccharomyces cerevisiae antibodies; and anti-flagellin) and any EIM (IgG and IgA, perinuclear anti-nuclear cytoplasmic antibody; anti-Saccharomyces cerevisiae antibodies; and anti-Pseudomonas fluorescens-associated sequence). We identified genome-wide significant associations within major histocompatibility complex (ankylosing spondylitis and sacroiliitis, P = 1.4E-15; OR, 2.5; 95% CI, 2.0-3.1; PSC, P = 2.7E-10; OR, 2.8; 95% CI, 2.0-3.8; ocular, P = 2E-08, OR, 3.6; 95% CI, 2.3-5.6; and overall EIM, P = 8.4E-09; OR, 2.2; 95% CI, 1.7-2.9) and CPEB4 (skin, P = 2.7E-08; OR, 1.5; 95% CI, 1.3-1.8). Genetic associations implicated tumor necrosis factor, JAK-STAT, and IL6 as potential targets for EIMs. Contrary to previous reports, only 2% of our subjects had multiple EIMs and most co-occurrences were negatively correlated.

CONCLUSIONS

We have identified demographic, clinical, and genetic associations with EIMs that revealed underlying mechanisms and implicated novel and existing drug targets-important steps toward a more personalized approach to IBD management.

Evolution of Symptoms After Ustekinumab Induction Therapy in Patients With Crohn's Disease

BACKGROUND & AIMS

Ustekinumab is an effective treatment of Crohn's disease (CD). Of interest to patients is knowing how soon symptoms may improve. We analyzed ustekinumab response dynamics from the ustekinumab CD trials.

METHODS

Patients with CD received intravenous induction with ustekinumab ∼6 mg/kg (n = 458) or placebo (n = 457). Week 8 ustekinumab responders received subcutaneous ustekinumab 90 mg as the first maintenance dose or as an extended induction dose for nonresponders. Patient-reported symptom changes (stool frequency, abdominal pain, general well-being) within the first 14 days and clinical outcomes through week 44 were evaluated using the CD Activity Index.

RESULTS

After ustekinumab infusion, stool frequency improvement was significantly (P < .05) greater than placebo on day 1 and for all patient-reported symptoms by day 10. In patients with no history of biologic failure or intolerance, cumulative clinical remission rates increased from 23.0% at week 3 to 55.5% at week 16 after the subcutaneous dose at week 8. Corresponding cumulative rates for patients with a history of biologic failure or intolerance increased from 12.9% to 24.1%. Neither change from baseline in CD Activity Index score nor week 8 ustekinumab pharmacokinetics were associated with week 16 response. Among all patients who received subcutaneous ustekinumab 90 mg q8w, up to 66.7% were in clinical response at week 44.

CONCLUSIONS

Ustekinumab induction provided symptom relief by day 1 post-infusion. Following ustekinumab infusion and a subcutaneous 90 mg injection, clinical outcomes continued to increase through week 16 and up to week 44. Regardless of week 8 clinical status or ustekinumab pharmacokinetics, patients should receive additional treatment at week 8.

CLINICALTRIALS

gov numbers, NCT01369329, NCT01369342, and NCT01369355.

Genetic coding variant in complement factor B (CFB) is associated with increased risk for perianal Crohn's disease and leads to impaired CFB cleavage and phagocytosis

OBJECTIVE

Perianal Crohn's disease (pCD) occurs in up to 40% of patients with CD and is associated with poor quality of life, limited treatment responses and poorly understood aetiology. We performed a genetic association study comparing CD subjects with and without perianal disease and subsequently performed functional follow-up studies for a pCD associated SNP in Complement Factor B (CFB).

DESIGN

Immunochip-based meta-analysis on 4056 pCD and 11 088 patients with CD from three independent cohorts was performed. Serological and clinical variables were analysed by regression analyses. Risk allele of rs4151651 was introduced into human CFB plasmid by site-directed mutagenesis. Binding of recombinant G252 or S252 CFB to C3b and its cleavage was determined in cell-free assays. Macrophage phagocytosis in presence of recombinant CFB or serum from CFB risk, or protective CD or healthy subjects was assessed by flow cytometry.

RESULTS

Perianal complications were associated with colonic involvement, OmpC and ASCA serology, and serology quartile sum score. We identified a genetic association for pCD (rs4151651), a non-synonymous SNP (G252S) in CFB, in all three cohorts. Recombinant S252 CFB had reduced binding to C3b, its cleavage was impaired, and complement-driven phagocytosis and cytokine secretion were reduced compared with G252 CFB. Serine 252 generates a de novo glycosylation site in CFB. Serum from homozygous risk patients displayed significantly decreased macrophage phagocytosis compared with non-risk serum.

CONCLUSION

pCD-associated rs4151651 in CFB is a loss-of-function mutation that impairs its cleavage, activation of alternative complement pathway, and pathogen phagocytosis thus implicating the alternative complement pathway and CFB in pCD aetiology.

Higher Intra-Abdominal Visceral Adipose Tissue Mass Is Associated With Lower Rates of Clinical and Endoscopic Remission in Patients With Inflammatory Bowel Diseases Initiating Biologic Therapy: Results of the Constellation Study

BACKGROUND & AIMS

We sought to assess the association between intra-abdominal visceral adipose tissue (IA-VAT) and response to 3 different biologic drugs in patients with inflammatory bowel disease (IBD) and to investigate its effects on inflammatory cytokine expression, pharmacokinetics, and intestinal microbiota.

METHODS

We prospectively enrolled subjects with active IBD initiating infliximab, vedolizumab, or ustekinumab and a healthy control group. Baseline body composition (including IA-VAT as percent of total body mass [IA-VAT%]) was measured using GE iDXA scan. Primary outcome was corticosteroid- free deep remission at weeks 14-16, defined as Harvey Bradshaw Index <5 for Crohn's disease and partial Mayo score <2 for ulcerative colitis, with a normal C-reactive protein and fecal calprotectin. Secondary outcomes were corticosteroid-free deep remission and endoscopic remission (Endoscopic Mayo Score ≤1 in ulcerative colitis or Simple Endoscopic Score for Crohn's disease ≤2) at weeks 30-46.

RESULTS

A total of 141 patients with IBD and 51 healthy controls were included. No differences in body composition parameters were seen between the IBD and healthy control cohorts. Patients with higher IA-VAT% were less likely to achieve corticosteroid-free deep remission (P < .001) or endoscopic remission (P = .02) vs those with lower IA-VAT%. Furthermore, nonresponders with high IA-VAT% had significantly higher serum interleukin-6 and tumor necrosis factor at baseline compared with responders and patients with low IA-VAT%. Drug pharmacokinetic properties and microbiota diversity were similar when comparing high and low IA-VAT% groups.

CONCLUSIONS

Higher IA-VAT% was independently associated with worse outcomes. This association could be driven at least partially by discrete differences in inflammatory cytokine expression.

Combination Therapy With Immunomodulators Improves the Pharmacokinetics of Infliximab But Not Vedolizumab or Ustekinumab

BACKGROUND AND AIMS

The aim of this study was to assess how 6-thioguanine nucleotide (6-TGN) levels and use of oral methotrexate relate to the pharmacokinetics of biologics.

METHODS

This was a prospective cohort study including patients with inflammatory bowel diseases on maintenance doses of infliximab, vedolizumab, or ustekinumab on monotherapy or combination with a thiopurine or oral methotrexate. We collected 6-TGN concentrations, biomarker levels, and clinical and endoscopic disease activity. The primary outcomes were infliximab, vedolizumab, and ustekinumab concentrations as well as anti-drug antibodies (ADAs).

RESULTS

A total of 369 patients were recruited (113 infliximab, 133 vedolizumab, and 123 ustekinumab). Patients with 6-TGN levels ≥146 pmol per 8 × 108 red blood cells (RBCs), and those receiving combination therapy with thiopurine or oral methotrexate had significantly higher infliximab concentrations when compared with monotherapy (median levels of 17.4 μg/mL on thiopurine with 6-TGN ≥146 pmol per 8 × 108 RBCs, 17.1 on methotrexate, and 3.9 on infliximab monotherapy; P = .001 for both comparisons). However, there was no association between the use of immunomodulators and 6-TGN concentrations with vedolizumab (median levels of 8.8 on thiopurine with 6-TGN ≥152 pmol per 8 × 108 RBCs, 6.8 on methotrexate, and 10.5 on vedolizumab monotherapy; P > .05 for both comparisons) or ustekinumab median concentrations (median levels of 5.0 on thiopurine with 6-TGN ≥154 pmol per 8 × 108 RBCs, 5.2 on methotrexate and 7.0 on ustekinumab monotherapy; P > .05 for both comparisons). Fourteen (12%) patients had anti-infliximab antibodies, while 1 patient had ADAs in each of the other drug cohorts.

CONCLUSIONS

Achieving higher 6-TGN levels or the use of methotrexate improved the pharmacokinetics of infliximab. Conversely, these data do not support the use of combination therapy to augment pharmacokinetics with vedolizumab or ustekinumab.

DR3 Regulates Intestinal Epithelial Homeostasis and Regeneration After Intestinal Barrier Injury

BACKGROUND & AIMS

Tumor necrosis factor (TNF) superfamily member tumor necrosis factor-like protein 1A (TL1A) has been associated with the susceptibility and severity of inflammatory bowel diseases. However, the function of the tumor necrosis factor-like protein 1A and its receptor death receptor 3 (DR3) in the development of intestinal inflammation is incompletely understood. We investigated the role of DR3 expressed by intestinal epithelial cells (IECs) during intestinal homeostasis, tissue injury, and regeneration.

METHODS

Clinical phenotype and histologic inflammation were assessed in C57BL/6 (wild-type), Tl1a-/- and Dr3-/- mice in dextran sulfate sodium (DSS)-induced colitis. We generated mice with an IEC-specific deletion of DR3 (Dr3ΔIEC) and assessed intestinal inflammation and epithelial barrier repair. In vivo intestinal permeability was assessed by fluorescein isothiocyanate dextran uptake. Proliferation of IECs was analyzed by bromodeoxyuridine incorporation. Expression of DR3 messenger RNA was assessed by fluorescent in situ hybridization. Small intestinal organoids were used to determine ex vivo regenerative potential.

RESULTS

Dr3-/- mice developed more severe colonic inflammation than wild-type mice in DSS-induced colitis with significantly impaired IEC regeneration. Homeostatic proliferation of IECs was increased in Dr3-/- mice, but blunted during regeneration. Cellular localization and expression of the tight junction proteins Claudin-1 and zonula occludens-1 were altered, leading to increased homeostatic intestinal permeability. Dr3ΔIEC mice recapitulated the phenotype observed in Dr3-/- mice with increased intestinal permeability and IEC proliferation under homeostatic conditions and impaired tissue repair and increased bacterial translocation during DSS-induced colitis. Impaired regenerative potential and altered zonula occludens-1 localization also were observed in Dr3ΔIEC enteroids.

CONCLUSIONS

Our findings establish a novel function of DR3 in IEC homeostasis and postinjury regeneration independent of its established role in innate lymphoid cells and T-helper cells.

Diagnostic and therapeutic potential of RNASET2 in Crohn's disease: Disease-risk polymorphism modulates allelic-imbalance in expression and circulating protein levels and recombinant-RNASET2 attenuates pro-inflammatory cytokine secretion

Ribonuclease T2 gene (RNASET2) variants are associated in genome wide association studies (GWAS) with risk for several autoimmune diseases, including Crohn's disease (CD). In T cells, a functional and biological relationship exists between TNFSF15-mediated enhancement of IFN-γ production, mucosal inflammation and RNASET2. Disease risk variants are associated with decreased mRNA expression and clinical characteristics of severe CD; however, functional classifications of variants and underlying molecular mechanisms contributing to pathogenesis remain largely unknown. In this study we demonstrate that allelic imbalance of RNASET2 disease risk variant rs2149092 is associated with transcriptional and post-transcriptional mechanisms regulating transcription factor binding, promoter-transactivation and allele-specific expression. RNASET2 mRNA expression decreases in response to multiple modes of T cell activation and recovers following elimination of activator. In CD patients with severe disease necessitating surgical intervention, preoperative circulating RNASET2 protein levels were decreased compared to non-IBD subjects and rebounded post-operatively following removal of the inflamed region, with levels associated with allelic carriage. Furthermore, overexpression or treatment with recombinant RNASET2 significantly reduced IFN-γ secretion. These findings reveal that RNASET2 cis- and trans-acting variation contributed regulatory complexity and determined expression and provide a basis for linking genetic variation with CD pathobiology. These data may ultimately identify RNASET2 as an effective therapeutic target in a subset of CD patients with severe disease.

BATF3 Protects Against Metabolic Syndrome and Maintains Intestinal Epithelial Homeostasis

The intestinal immune system and microbiota are emerging as important contributors to the development of metabolic syndrome, but the role of intestinal dendritic cells (DCs) in this context is incompletely understood. BATF3 is a transcription factor essential in the development of mucosal conventional DCs type 1 (cDC1). We show that Batf3-/- mice developed metabolic syndrome and have altered localization of tight junction proteins in intestinal epithelial cells leading to increased intestinal permeability. Treatment with the glycolysis inhibitor 2-deoxy-D-glucose reduced intestinal inflammation and restored barrier function in obese Batf3-/- mice. High-fat diet further enhanced the metabolic phenotype and susceptibility to dextran sulfate sodium colitis in Batf3-/- mice. Antibiotic treatment of Batf3-/- mice prevented metabolic syndrome and impaired intestinal barrier function. Batf3-/- mice have altered IgA-coating of fecal bacteria and displayed microbial dysbiosis marked by decreased obesity protective Akkermansia muciniphila, and Bifidobacterium. Thus, BATF3 protects against metabolic syndrome and preserves intestinal epithelial barrier by maintaining beneficial microbiota.

Development of a Personalized Intestinal Fibrosis Model Using Human Intestinal Organoids Derived From Induced Pluripotent Stem Cells

BACKGROUND

Intestinal fibrosis is a serious complication of Crohn's disease. Numerous cell types including intestinal epithelial and mesenchymal cells are implicated in this process, yet studies are hampered by the lack of personalized in vitro models. Human intestinal organoids (HIOs) derived from induced pluripotent stem cells (iPSCs) contain these cell types, and our goal was to determine the feasibility of utilizing these to develop a personalized intestinal fibrosis model.

METHODS

iPSCs from 2 control individuals and 2 very early onset inflammatory bowel disease patients with stricturing complications were obtained and directed to form HIOs. Purified populations of epithelial and mesenchymal cells were derived from HIOs, and both types were treated with the profibrogenic cytokine transforming growth factor β (TGFβ). Quantitative polymerase chain reaction and RNA sequencing analysis were used to assay their responses.

RESULTS

In iPSC-derived mesenchymal cells, there was a significant increase in the expression of profibrotic genes (Col1a1, Col5a1, and TIMP1) in response to TGFβ. RNA sequencing analysis identified further profibrotic genes and demonstrated differential responses to this cytokine in each of the 4 lines. Increases in profibrotic gene expression (Col1a1, FN, TIMP1) along with genes associated with epithelial-mesenchymal transition (vimentin and N-cadherin) were observed in TGFβ -treated epithelial cells.

CONCLUSIONS

We demonstrate the feasibility of utilizing iPSC-HIO technology to model intestinal fibrotic responses in vitro. This now permits the generation of near unlimited quantities of patient-specific cells that could be used to reveal cell- and environmental-specific mechanisms underpinning intestinal fibrosis.

TNF-Like Ligand 1 Aberrance Aggravates Nonalcoholic Steatohepatitis via M1 Macrophage Polarization

Nonalcoholic steatohepatitis (NASH) is a progressive, chronic liver disease worldwide which imposes a large economic burden on society. M1/M2 macrophage balance destruction and recruitment of mononuclear immune cells to the liver play critical roles in NASH. Several studies have shown that the expression of TNF-like ligand 1 aberrance (TL1A) increased in macrophages associated with many inflammatory diseases, for example, inflammatory bowel disease, primary biliary cholangitis, and liver fibrosis. One recent research showed that weight, abdominal adipose, and liver leptin, one of the critical fat cytokines, were reduced in TL1A knockout mice. However, the functional and molecular regulatory mechanisms of TL1A on macrophage polarization and recruitment in NASH have yet to be clarified. The authors found that high fructose high fat diet and methionine-choline deficiency diet induced the expression of TL1A in macrophages of liver tissue from murine NASH models. Myeloid-specific TL1A overexpressed mice showed exacerbated steatohepatitis with increased hepatic lipid accumulation, inflammation, liver injury, and apoptosis. M1 macrophages' infiltration and the production of proinflammatory and chemotactic cytokines increased in liver of NASH mouse models with myeloid-specific TL1A overexpressed. Furthermore, this paper revealed that bone marrow-derived macrophages and Kupffer cells with overexpression of TL1A exacerbated the lipid accumulation and expression of proinflammatory factors in the murine primary hepatocytes after free fatty acid treatment in vitro. In conclusion, TL1A-mediated M1-type macrophage polarization and recruitment into the liver promoted steatohepatitis in murine NASH.

Preoperative Serum Vedolizumab Levels Do Not Impact Postoperative Outcomes in Inflammatory Bowel Disease

BACKGROUND

Vedolizumab has been proposed to lead to fewer postoperative complications because of its gut specificity. Studies, however, suggest an increased risk of surgical site infections, yet the data are conflicting.

OBJECTIVE

This study aimed to assess the effect of vedolizumab drug levels on postoperative outcomes in patients undergoing major abdominal surgery for IBD.

DESIGN

This was a retrospective study of a prospectively maintained database.

SETTING

Patients were operated on by a single surgeon at an academic medical center.

PATIENTS

A total of 72 patients with IBD undergoing major abdominal surgery were included.

INTERVENTIONS

Patients were exposed preoperatively to vedolizumab.

MAIN OUTCOME MEASURES

The primary outcome measured was the postoperative morbidity in patients who had IBD with detectable vs undetectable vedolizumab levels.

RESULTS

A total of 72 patients were included in the study. Thirty-eight patients had detectable vedolizumab levels (>1.6 μg/mL), and 34 had undetectable vedolizumab levels. The overall rate of complications was 39%, and ileus was the most common complication. There were no significant differences in clinical variables between the detectable and undetectable vedolizumab level patient groups except for the time between the last dose and surgery (p < 0.01). There were 42 patients in the ulcerative colitis cohort; 48% had an undetectable vedolizumab level and 52% had a detectable vedolizumab level. There were no differences in any postoperative morbidity between ulcerative colitis groups. The Crohn's cohort had 27 patients; 48% had an undetectable vedolizumab levels and 52% had a detectable vedolizumab level. There was a significantly lower incidence of postoperative ileus in patients who had Crohn's disease with detectable vedolizumab levels compared with patients with an undetectable vedolizumab level (p < 0.04).

LIMITATIONS

Limitations include a low overall patient population and a high rate of stoma formation.

CONCLUSIONS

Serum vedolizumab levels do not influence postoperative morbidity in IBD. Vedolizumab may reduce the incidence of postoperative ileus in patients with Crohn's disease. See Video Abstract at http://links.lww.com/DCR/B574.

LOS NIVELES DE VEDOLIZUMAB EN SUERO PREOPERATORIO, NO AFECTAN LOS RESULTADOS POSTOPERATORIOS EN LA ENFERMEDAD INFLAMATORIA INTESTINAL

ANTECEDENTES:Se ha propuesto que el vedolizumab presenta menos complicaciones postoperatorias debido a su especificidad intestinal. Sin embargo, estudios sugieren un mayor riesgo de infecciones en el sitio quirúrgico, aunque los datos son contradictorios.OBJETIVO:Evaluar el efecto en los niveles del fármaco vedolizumab, en resultados postoperatorios de pacientes sometidos a cirugía mayor abdominal, por enfermedad inflamatoria intestinal.DISEÑO:Estudio retrospectivo de una base de datos mantenida prospectivamente.ENTORNO CLÍNICO:Pacientes intervenidos por un solo cirujano en un centro médico académico.PACIENTES:Un total de 72 pacientes con enfermedad inflamatoria intestinal sometidos a cirugía mayor abdominal.INTERVENCIONES:Exposición preoperatoria a vedolizumab.PRINCIPALES MEDIDAS DE VALORACIÓN:Morbilidad postoperatoria en pacientes con enfermedad inflamatoria intestinal, con niveles detectables versus no detectables de vedolizumab.RESULTADOS:Se incluyó en el estudio a un total de 72 pacientes. Treinta y ocho pacientes tuvieron niveles detectables de vedolizumab (> 1,6 mcg / ml) y 34 con niveles no detectables de vedolizumab. La tasa global de complicaciones fue del 39% y el íleo fue la complicación más común. No hubo diferencias significativas en las variables clínicas entre los grupos de pacientes con niveles detectables y no detectables de vedolizumab, excepto por el intervalo de tiempo entre la última dosis y la cirugía (p <.01). La cohorte de colitis ulcerosa tuvo 42 pacientes, el 48% con un nivel no detectable de vedolizumab y el 52% un nivel detectable de vedolizumab. No hubo diferencias en ninguna morbilidad postoperatoria entre los grupos de colitis ulcerosa. La cohorte de Crohn tuvo 27 pacientes, 48% con niveles no detectables de vedolizumab y el 52% con niveles detectables de vedolizumab. Hubo una incidencia significativamente menor de íleo postoperatorio en pacientes de Crohn con niveles detectables de vedolizumab, comparados con los pacientes con un nivel no detectable de vedolizumab (p <0,04).LIMITACIONES:Las limitaciones incluyen una baja población general de pacientes y una alta tasa de formación de estomas.CONCLUSIONES:Los niveles séricos de vedolizumab no influyen en la morbilidad postoperatoria de la enfermedad inflamatoria intestinal. Vedolizumab puede reducir la incidencia de íleo postoperatorio en pacientes de Crohn. Consulte Video Resumen en http://links.lww.com/DCR/B574.

Antitumour necrosis factor therapy is associated with de novo Crohn's disease after ileal pouch-anal anastomosis

AIM

Tumour necrosis factor inhibitors (TNFi) have revolutionized the management of moderate to severe ulcerative colitis (UC) since their approval for UC in 2005. However, many patients ultimately require surgery with ileal pouch-anal anastomosis (IPAA). Development of de novo Crohn's disease (CD) following IPAA is an increasingly common and devastating complication, sometimes progressing to pouch failure. The aim of this study was to evaluate the association of preoperative TNFi exposure and the development of de novo CD after IPAA.

METHOD

A prospective single-centre inflammatory bowel disease (IBD) registry was searched for consecutive patients with UC undergoing IPAA during a 25-year period ending July 2018. Patients with preoperative CD or IBD-unclassified were excluded. De novo CD was diagnosed upon endoscopic evidence of five or more mucosal ulcers proximal to the ileal pouch any time after surgery and/or pouch fistula occurring more than three months after ileostomy closure.

RESULTS

The study cohort consisted of 400 patients with a median follow-up of 44.0 (IQR 11-113) months. Sixty-two (16%) patients developed de novo CD 28.0 (IQR 6-67) months following ileostomy closure. Survival analysis of TNFi era patients revealed a significant increase in de novo CD risk in those with preoperative TNFi exposure. Multivariable proportional hazards modelling revealed two independent predictors for de novo CD development: older age was protective (HR 0.89 per 5-year increase; P = 0.009) and preoperative TNFi exposure was hazardous (HR 2.10; P = 0.011).

CONCLUSION

This prospective study is the first to suggest an association between preoperative TNFi exposure and the development of de novo CD.

Effect and Mechanism of TL1A Expression on Epithelial-Mesenchymal Transition during Chronic Colitis-Related Intestinal Fibrosis

BACKGROUND AND AIMS

Recent evidences reveal that epithelial to mesenchymal transition (EMT) exacerbates the process of intestinal fibrosis. Tumor necrosis factor-like ligand 1A (TL1A) is a member of the tumor necrosis family (TNF), which can take part in the development of colonic inflammation and fibrosis by regulating immune response or inflammatory factors. The purpose of this study was to elucidate the possible contribution of TL1A in onset and progression of intestinal inflammation and fibrosis through EMT.

METHODS

Colonic specimens were obtained from patients with inflammatory bowel disease (IBD) and control individuals. The expression levels of TL1A and EMT-related markers in intestinal tissues were evaluated. Furthermore, the human colorectal adenocarcinoma cell line, HT-29, was stimulated with TL1A, anti-TL1A antibody, or BMP-7 to assess EMT process. In addition, transgenic mice expressing high levels of TL1A in lymphoid cells were used to further investigate the mechanism of TL1A in intestinal fibrosis.

RESULTS

High levels of TL1A expression were detected in the intestinal specimens of patients with ulcerative colitis and Crohn's disease and were negatively associated with the expression of an epithelial marker (E-cadherin), while it was positively associated with the expression of interstitial markers (FSP1 and α-SMA). Transgenic mice with high expression of TL1A were more sensitive to dextran sodium sulfate and exhibited severe intestinal inflammation and fibrosis. Additionally, the TGF-β1/Smad3 pathway may be involved in TL1A-induced EMT, and the expression of IL-13 and EMT-related transcriptional molecules (e.g., ZEB1 and Snail1) was increased in the intestinal specimens of the transgenic mice. Furthermore, TL1A-induced EMT can be influenced by anti-TL1A antibody or BMP-7 in vitro.

CONCLUSIONS

TL1A participates in the formation and process of EMT in intestinal fibrosis. This new knowledge enables us to better understand the pathogenesis of intestinal fibrosis and identify new therapeutic targets for its treatment.

Altered Intestinal ACE2 Levels Are Associated With Inflammation, Severe Disease, and Response to Anti-Cytokine Therapy in Inflammatory Bowel Disease

BACKGROUND AND AIMS

The host receptor for severe acute respiratory syndrome coronavirus 2, angiotensin-converting enzyme 2 (ACE2), is highly expressed in small bowel (SB). Our aim was to identify factors influencing intestinal ACE2 expression in Crohn's disease (CD), ulcerative colitis (UC), and non-inflammatory bowel disease (IBD) controls.

METHODS

Using bulk RNA sequencing or microarray transcriptomics from tissue samples (4 SB and 2 colonic cohorts; n = 495; n = 387 UC; n = 94 non-IBD), we analyzed the relationship between ACE2 with demographics and disease activity and prognosis. We examined the outcome of anti-tumor necrosis factor and anti-interleukin-12/interleukin-23 treatment on SB and colonic ACE2 expression in 3 clinical trials. Univariate and multivariate regression models were fitted.

RESULTS

ACE2 levels were consistently reduced in SB CD and elevated in colonic UC compared with non-IBD controls. Elevated SB ACE2 was also associated with demographic features (age and elevated body mass index) associated with poor coronavirus disease 2019 outcomes. Within CD, SB ACE2 was reduced in patients subsequently developing complicated disease. Within UC, colonic ACE2 was elevated in active disease and in patients subsequently requiring anti-tumor necrosis factor rescue therapy. SB and colonic ACE2 expression in active CD and UC were restored by anti-cytokine therapy, most notably in responders.

CONCLUSIONS

Reduced SB but elevated colonic ACE2 levels in IBD are associated with inflammation and severe disease, but normalized after anti-cytokine therapy, suggesting compartmentalization of ACE2-related biology in SB and colonic inflammation. The restoration of ACE2 expression with anti-cytokine therapy might be important in the context of severe acute respiratory syndrome coronavirus 2 infection and potentially explain reports of reduced morbidity from coronavirus disease 2019 in IBD patients treated with anti-cytokines.

Modeling Intestinal Epithelial Response to Interferon-γ in Induced Pluripotent Stem Cell-Derived Human Intestinal Organoids

Human intestinal organoids (HIOs) are increasingly being used to model intestinal responses to various stimuli, yet few studies have confirmed the fidelity of this modeling system. Given that the interferon-gamma (IFN-γ) response has been well characterized in various other cell types, our goal was to characterize the response to IFN-γ in HIOs derived from induced pluripotent stem cells (iPSCs). To achieve this, iPSCs were directed to form HIOs and subsequently treated with IFN-γ. Our results demonstrate that IFN-γ phosphorylates STAT1 but has little effect on the expression or localization of tight and adherens junction proteins in HIOs. However, transcriptomic profiling by microarray revealed numerous upregulated genes such as IDO1, GBP1, CXCL9, CXCL10 and CXCL11, which have previously been shown to be upregulated in other cell types in response to IFN-γ. Notably, "Response to Interferon Gamma" was determined to be one of the most significantly upregulated gene sets in IFN-γ-treated HIOs using gene set enrichment analysis. Interestingly, similar genes and pathways were upregulated in publicly available datasets contrasting the gene expression of in vivo biopsy tissue from patients with IBD against healthy controls. These data confirm that the iPSC-derived HIO modeling system represents an appropriate platform to evaluate the effects of various stimuli and specific environmental factors responsible for the alterations in the intestinal epithelium seen in various gastrointestinal conditions such as inflammatory bowel disease.

Pre-pouch Ileitis is Associated with Development of Crohn's Disease-like Complications and Pouch Failure

BACKGROUND AND AIMS

It is unclear whether pre-pouch ileitis heralds an aggressive inflammatory pouch disease in patients with ileal pouch-anal anastomosis [IPAA]. We compared outcomes of patients with pouchitis and concomitant pre-pouch ileitis with those with pouchitis alone.

METHODS

Patients undergoing IPAA surgery for inflammatory bowel disease, who subsequently developed pouchitis with concomitant pre-pouch ileitis [pre-pouch ileitis group], were matched by year of IPAA surgery and preoperative diagnosis [ulcerative colitis or inflammatory bowel disease-unclassified] with patients who developed pouchitis alone [pouchitis group]. Primary outcomes were development of Crohn's disease [CD]-like complications [non-anastomotic strictures or perianal disease >6 months after ileostomy closure] and pouch failure. Secondary outcomes were need for surgical/endoscopic interventions and immunosuppressive therapy. Log-rank testing was used to compare outcome-free survival, and Cox regression was performed to identify predictors of outcomes.

RESULTS

There were 66 patients in each group. CD-like complications and pouch failure developed in 36.4% and 7.6% patients in the pre-pouch ileitis group and 10.6% and 1.5% in pouchitis group, respectively. CD-like complications-free survival [log-rank p = 0.0002] and pouch failure-free survival [log-rank p = 0.046] were significantly lower in the pre-pouch ileitis group. The pre-pouch ileitis group had a higher risk of requiring surgical/endoscopic interventions [log-rank p = 0.0005] and immunosuppressive therapy [log-rank p <0.0001]. Pre-pouch ileitis was independently associated with an increased risk of CD-like complications (hazard ratio [HR] 3.8; p = 0.0007), need for surgical/endoscopic interventions [HR 4.1; p = 0.002], and immunosuppressive therapy [HR 5.0; p = 0.0002].

CONCLUSIONS

Pre-pouch ileitis is associated with a higher risk of complicated disease and pouch failure than pouchitis. It should be considered a feature of CD.

TL1A primed dendritic cells activation exacerbated chronic murine colitis

AIMS

Tumor necrosis factor-like ligand 1A (TL1A) has been proved to activate adaptive immunity in inflammatory bowel disease (IBD). However, its role in the regulation of intestinal dendritic cells (DCs) has not been fully characterized. This study aims to investigate the modulation of TL1A in DCs activation in murine colitis.

MATERIALS AND METHODS

Myeloid TL1A-Transgenic C57BL/6 mice and wild-type (WT) mice were administrated with dextran sulfate sodium (DSS) to explore the effects of TL1A in murine colitis. Bone marrow-derived DCs (BMDCs) were isolated to detect the ability of antigen phagocytosis and presentation. The expression of nuclear factor-κB (NF-κB) pathway and chemokines receptors (CCRs) was assessed by real-time PCR and Western blot.

KEY FINDINGS

Myeloid cells with constitutive TL1A expression developed worsened murine colitis with exacerbated T_H1/T_H17 cytokine responses. Intestinal DCs from TL1A transgenic mice expressed high levels of costimulatory molecules (CD80 and CD86) with increased pro-inflammatory cytokines of IL-1β, TNF-α and IL-12/23 p40. Mechanistic studies showed that TL1A enhanced the phagocytotic ability of BMDCs. Moreover, TL1A enhanced the capacity of antigen process and presentation in BMDCs. Besides, TL1A induced the phosphorylation of NF-κB(p65) and IκBα. Meanwhile, higher expression of CCR2, CCR5, CCR7, and CX3CR1 was observed both in vivo and in vitro.

SIGNIFICANCE

TL1A exacerbated DSS-induced chronic experimental colitis, probably through activation and migration of dendritic cells, and therefore increasing the secretion of pro-inflammatory cytokines.

Direct signaling of TL1A-DR3 on fibroblasts induces intestinal fibrosis in vivo

Tumor necrosis factor-like cytokine 1A (TL1A, TNFSF15) is implicated in inflammatory bowel disease, modulating the location and severity of inflammation and fibrosis. TL1A expression is increased in inflamed mucosa and associated with fibrostenosing Crohn's disease. Tl1a-overexpression in mice causes spontaneous ileitis, and exacerbates induced proximal colitis and fibrosis. Intestinal fibroblasts express Death-receptor 3 (DR3; the only know receptor for TL1A) and stimulation with TL1A induces activation in vitro. However, the contribution of direct TL1A-DR3 activation on fibroblasts to fibrosis in vivo remains unknown. TL1A overexpressing naïve T cells were transferred into Rag-/- , Rag-/- mice lacking DR3 in all cell types (Rag-/-Dr3-/-), or Rag-/- mice lacking DR3 only on fibroblasts (Rag-/-Dr3∆Col1a2) to induce colitis and fibrosis, assessed by clinical disease activity index, intestinal inflammation, and collagen deposition. Rag-/- mice developed overt colitis with intestinal fibrostenosis. In contrast, Rag-/-Dr3-/- demonstrated decreased inflammation and fibrosis. Despite similar clinical disease and inflammation as Rag-/-, Rag-/-Dr3∆Col1a2 exhibited reduced intestinal fibrosis and attenuated fibroblast activation and migration. RNA-Sequencing of TL1A-stimulated fibroblasts identified Rho signal transduction as a major pathway activated by TL1A and inhibition of this pathway modulated TL1A-mediated fibroblast functions. Thus, direct TL1A signaling on fibroblasts promotes intestinal fibrosis in vivo. These results provide novel insight into profibrotic pathways mediated by TL1A paralleling its pro-inflammatory effects.

Toll-like receptor 7 protects against intestinal inflammation and restricts the development of tissue-resident memory CD8+ T cells

The maintenance of intestinal homeostasis depends on a complex interaction between microbiota, intestinal epithelial barrier, and the immune system. Alteration in of one of these components could lead to the development of inflammatory bowel diseases (IBD). Norovirus infection of mice with a mutation in the Crohn’s disease susceptibility gene Atg16L1 induces intestinal inflammation. Moreover, persistent norovirus infection leads to intestinal virus-specific CD8+ T cells responses. However, the role of the enteric virome in IBD is still poorly understood. Toll-like receptor 7 (TLR7) recognizes single-stranded RNA viruses. Here, we investigate the role of TLR7 in intestinal homeostasis and inflammation. At steady state, Tlr7−/− mice have an approx. 10-fold increase in small and large intestinal lamina propria (LP) granzyme B+ tissue-resident memory (Trm) CD8+ T cells compared to WT mice (WT: 5.5, Tlr7−/−: 59.5 %, p &lt; 0.005), reminiscent of persistent norovirus infection. Furthermore, Tlr7−/− mice were more susceptible to dextran sulfate sodium (DSS) colitis with more severe inflammation (Histoscore: WT: 7.6, Tlr7−/−: 12.7, p &lt; 0.005), increased disease activity index (WT: 5.5, Tlr7−/−: 7.4, p &lt; 0.05), and increased secretion of IFNg (WT: 5.2, Tlr7−/−: 24.2 ng/ml, p &lt; 0.005) and TNFα (WT: 108.6, Tlr7−/−: 191.8 pg/ml, p &lt; 0.05). Increased colonic inflammation was associated with increased LP Trm CD8+ T cells (WT: 3.9, Tlr7−/−: 42.0 %, p &lt; 0.005). Our data shows that TLR7-deficiency promotes the development of LP Trm CD8+ T cells and increases susceptibility to DSS colitis. In conclusion, TLR7 plays an important role in maintaining immune response to intestinal viruses and protects against development of colitis.

Reduced expression of COVID-19 host receptor, ACE2 is associated with small bowel inflammation, more severe disease, and response to anti-TNF therapy in Crohn's disease

Angiotensin-Converting Enzyme 2 ( ACE2 ) has been identified as the host receptor for SARS-coronavirus 2 (SARS-CoV-2) which has infected millions world-wide and likely caused hundreds of thousands of deaths. Utilizing transcriptomic data from four cohorts taken from Crohn's disease (CD) and non-inflammatory bowel disease (IBD) subjects, we observed evidence of increased ACE2 mRNA in ileum with demographic features that have been associated with poor outcomes in COVID-19 including age and raised BMI. ACE2 was downregulated in CD compared to controls in independent cohorts. Within CD, ACE2 expression was reduced in inflamed ileal tissue and also remarkably, from uninvolved tissue in patients with a worse prognosis in both adult and pediatric cohorts. In active CD, small bowel ACE2 expression was restored by anti-TNF therapy particularly in anti-TNF responders. Collectively our data suggest that ACE2 downregulation is associated with inflammation and worse outcomes in CD.

Development of Physiologically Responsive Human iPSC-Derived Intestinal Epithelium to Study Barrier Dysfunction in IBD

In inflammatory bowel disease (IBD), the intestinal epithelium is characterized by increased permeability both in active disease and remission states. The genetic underpinnings of this increased intestinal permeability are largely unstudied, in part due to a lack of appropriate modelling systems. Our aim is to develop an in vitro model of intestinal permeability using induced pluripotent stem cell (iPSC)-derived human intestinal organoids (HIOs) and human colonic organoids (HCOs) to study barrier dysfunction. iPSCs were generated from healthy controls, adult onset IBD, and very early onset IBD (VEO-IBD) patients and differentiated into HIOs and HCOs. EpCAM+ selected cells were seeded onto Transwell inserts and barrier integrity studies were carried out in the presence or absence of pro-inflammatory cytokines TNFα and IFNγ. Quantitative real-time PCR (qRT-PCR), transmission electron microscopy (TEM), and immunofluorescence were used to determine altered tight and adherens junction protein expression or localization. Differentiation to HCO indicated an increased gene expression of CDX2, CD147, and CA2, and increased basal transepithelial electrical resistance compared to HIO. Permeability studies were carried out in HIO- and HCO-derived epithelium, and permeability of FD4 was significantly increased when exposed to TNFα and IFNγ. TEM and immunofluorescence imaging indicated a mislocalization of E-cadherin and ZO-1 in TNFα and IFNγ challenged organoids with a corresponding decrease in mRNA expression. Comparisons between HIO- and HCO-epithelium show a difference in gene expression, electrophysiology, and morphology: both are responsive to TNFα and IFNγ stimulation resulting in enhanced permeability, and changes in tight and adherens junction architecture. This data indicate that iPSC-derived HIOs and HCOs constitute an appropriate physiologically responsive model to study barrier dysfunction and the role of the epithelium in IBD and VEO-IBD.

Epithelial endoplasmic reticulum stress orchestrates a protective IgA response

Immunoglobulin A (IgA) is the major secretory immunoglobulin isotype found at mucosal surfaces, where it regulates microbial commensalism and excludes luminal factors from contacting intestinal epithelial cells (IECs). IgA is induced by both T cell-dependent and -independent (TI) pathways. However, little is known about TI regulation. We report that IEC endoplasmic reticulum (ER) stress induces a polyreactive IgA response, which is protective against enteric inflammation. IEC ER stress causes TI and microbiota-independent expansion and activation of peritoneal B1b cells, which culminates in increased lamina propria and luminal IgA. Increased numbers of IgA-producing plasma cells were observed in healthy humans with defective autophagy, who are known to exhibit IEC ER stress. Upon ER stress, IECs communicate signals to the peritoneum that induce a barrier-protective TI IgA response.

Ileal Gene Expression Data from Crohn's Disease Small Bowel Resections Indicate Distinct Clinical Subgroups

BACKGROUND AND AIMS

Heterogeneity in Crohn's disease [CD] provides a challenge for the development of effective therapies. Our goal was to define a unique molecular signature for severe, refractory CD to enable precision therapy approaches to disease treatment and to facilitate earlier intervention in complicated disease.

METHODS

We analysed clinical metadata, genetics, and transcriptomics from uninvolved ileal tissue from CD patients who underwent a single small bowel resection. We determined transcriptional risk scores, cellular signatures, and mechanistic pathways that define patient subsets in refractory CD.

RESULTS

Within refractory CD, we found three CD patient subgroups [CD1, CD2, and CD3]. Compared with CD1, CD3 was enriched for subjects with increased disease recurrence after first surgery [OR = 6.78, p = 0.04], enhanced occurrence of second surgery [OR = 5.07, p = 0.016], and presence of perianal CD [OR = 3.61, p = 0.036]. The proportion of patients with recurrence-free survival was smaller in CD3 than in CD1 (p = 0.02, median survival time [months] in CD1 = 10 and CD3 = 6). Overlaying differential gene expression between CD1 and CD3 on CD subgroup-associated genetic polymorphisms identified 174 genes representing both genetic and biological differences between the CD subgroups. Pathway analyses using this unique gene signature indicated eukaryotic initiation factor 2 [eIF2] and cyclic adenosine monophosphate [cAMP] signalling to be dominant pathways associated with CD3. Furthermore, the severe, refractory subset, CD3, was associated with a higher transcriptional risk score and enriched with eosinophil and natural killer T [NKT] cell gene signatures.

CONCLUSION

We characterized a subset of severe, refractory CD patients who may need more aggressive treatment after first resection and who are likely to benefit from targeted therapy based on their genotype and tissue gene expression signature.

A role for BATF3 in TH9 differentiation and T-cell-driven mucosal pathologies

T helper 9 (T_H9) cells are important for the development of inflammatory and allergic diseases. The T_H9 transcriptional network converges signals from cytokines and antigen presentation but is incompletely understood. Here, we identified TL1A, a member of the TNF superfamily, as a strong inducer of mouse and human T_H9 differentiation. Mechanistically, TL1A induced the expression of the transcription factors BATF and BATF3 and facilitated their binding to the Il9 promoter leading to enhanced secretion of IL-9. BATF- and BATF3-deficiencies impaired IL-9 secretion under T_H9 and T_H9-TL1A-polarizing conditions. In vivo, using a T-cell transfer model, we demonstrated that TL1A promoted IL-9-dependent, T_H9 cell-induced intestinal and lung inflammation. Neutralizing IL-9 antibodies attenuated TL1A-driven mucosal inflammation. Batf3^-/- T_H9-TL1A cells induced reduced inflammation and cytokine expression in vivo compared to WT cells. Our results demonstrate that TL1A promotes T_H9 cell differentiation and function and define a role for BATF3 in T-cell-driven mucosal inflammation.

Malassezia Is Associated with Crohn's Disease and Exacerbates Colitis in Mouse Models

Inflammatory bowel disease (IBD) is characterized by alterations in the intestinal microbiota and altered immune responses to gut microbiota. Evidence is accumulating that IBD is influenced by not only commensal bacteria but also commensal fungi. We characterized fungi directly associated with the intestinal mucosa in healthy people and Crohn's disease patients and identified fungi specifically abundant in patients. One of these, the common skin resident fungus Malassezia restricta, is also linked to the presence of an IBD-associated polymorphism in the gene for CARD9, a signaling adaptor important for anti-fungal defense. M. restricta elicits innate inflammatory responses largely through CARD9 and is recognized by Crohn's disease patient anti-fungal antibodies. This yeast elicits strong inflammatory cytokine production from innate cells harboring the IBD-linked polymorphism in CARD9 and exacerbates colitis via CARD9 in mouse models of disease. Collectively, these results suggest that targeting specific commensal fungi may be a therapeutic strategy for IBD.

Microbiota-Induced TNF-like Ligand 1A Drives Group 3 Innate Lymphoid Cell-Mediated Barrier Protection and Intestinal T Cell Activation during Colitis

Inflammatory bowel disease (IBD) results from a dysregulated interaction between the microbiota and a genetically susceptible host. Genetic studies have linked TNFSF15 polymorphisms and its protein TNF-like ligand 1A (TL1A) with IBD, but the functional role of TL1A is not known. Here, we found that adherent IBD-associated microbiota induced TL1A release from CX3CR1+ mononuclear phagocytes (MNPs). Using cell-specific genetic deletion models, we identified an essential role for CX3CR1+MNP-derived TL1A in driving group 3 innate lymphoid cell (ILC3) production of interleukin-22 and mucosal healing during acute colitis. In contrast to this protective role in acute colitis, TL1A-dependent expression of co-stimulatory molecule OX40L in MHCII+ ILC3s during colitis led to co-stimulation of antigen-specific T cells that was required for chronic T cell colitis. These results identify a role for ILC3s in activating intestinal T cells and reveal a central role for TL1A in promoting ILC3 barrier immunity during colitis.

Late-Onset Crohn's Disease Is A Subgroup Distinct in Genetic and Behavioral Risk Factors With UC-Like Characteristics

BACKGROUND

Age of onset is linked to variations in clinical phenotypes and natural history in Crohn's disease (CD). We aim to define etiologically more homogenous subgroups in CD based on ages of onset.

METHODS

We examined the distribution of CD polygenetic risk score (PRS) across ages of diagnosis in a Caucasian cohort of 2344 independent CD patients. We identified subgroups with a distinct distribution of PRS and compared those groups in genetics, demographic characteristics, clinical subphenotypes, and serological markers. The results were replicated in an independent cohort of 13,065 CD patients from the International Inflammatory Bowel Diseases Genetic Consortium (IIBDGC).

RESULTS

We identified a late-onset (LO) subgroup in CD (age at diagnosis ≥ 55 years) with significantly lower PRS compared with the intermediate group (age at diagnosis between 5 and 55 years) in both cohorts. Smoking cessation, a risk factor for ulcerative colitis (UC) and protective factor for CD, had a higher rate in this LO subgroup in comparison with the intermediate group. We also compared the LO group with the intermediate group, and, consistent with previous reports, the LO group more often had colonic CD, had less penetrating disease behavior, and had less need for surgery. Serological analysis showed that LO CD patients were more antineutrophil cytoplasmic antibody positive and less antisaccharomyces cerevisiae antibody positive compared with the intermediate group. Variance component analysis indicated that overall genetic contribution to LO CD was lower relative to the middle group, and genetic heterogeneity testing indicated that LO CD was different from the middle group in underlying genetic architecture.

CONCLUSIONS

Late-onset CD is subgroup distinct in genetic and behavioral risk factors with UC-like characteristics. 10.1093/ibd/izy148_video1izy148.video15791413461001.

Plasma N-Glycan Signatures Are Associated With Features of Inflammatory Bowel Diseases

BACKGROUND & AIMS

Biomarkers are needed for early detection of Crohn's disease (CD) and ulcerative colitis (UC) or to predict patient outcomes. Glycosylation is a common and complex posttranslational modification of proteins that affects their structure and activity. We compared plasma N-glycosylation profiles between patients with CD or UC and healthy individuals (controls).

METHODS

We analyzed the total plasma N-glycomes of 2635 patients with inflammatory bowel diseases and 996 controls by mass spectrometry with a linkage-specific sialic acid derivatization technique. Plasma samples were acquired from 2 hospitals in Italy (discovery cohort, 1989 patients with inflammatory bowel disease [IBD] and 570 controls) and 1 medical center in the United States (validation cohort, 646 cases of IBD and 426 controls). Sixty-three glycoforms met our criteria for relative quantification and were extracted from the raw data with the software MassyTools. Common features shared by the glycan compositions were combined in 78 derived traits, including the number of antennae of complex-type glycans and levels of fucosylation, bisection, galactosylation, and sialylation. Associations of plasma N-glycomes with age, sex, CD, UC, and IBD-related parameters such as disease location, surgery and medication, level of C-reactive protein, and sedimentation rate were tested by linear and logistic regression.

RESULTS

Plasma samples from patients with IBD had a higher abundance of large-size glycans compared with controls, a decreased relative abundance of hybrid and high-mannose structures, lower fucosylation, lower galactosylation, and higher sialylation (α2,3- and α2,6-linked). We could discriminate plasma from patients with CD from that of patients with UC based on higher bisection, lower galactosylation, and higher sialylation (α2,3-linked). Glycosylation patterns were associated with disease location and progression, the need for a more potent medication, and surgery. These results were replicated in a large independent cohort.

CONCLUSIONS

We performed high-throughput analysis to compare total plasma N-glycomes of individuals with vs without IBD and to identify patterns associated with disease features and the need for treatment. These profiles might be used in diagnosis and for predicting patients' responses to treatment.

Serological, genetic and clinical associations with increased health-care resource utilization in inflammatory bowel disease

OBJECTIVE

Inflammatory bowel diseases (IBD) are associated with significant morbidity and economic burden. The variable course of IBD creates a need for predictors of clinical outcomes and health resource utilization (HRU) to guide treatment decisions. We aimed to identify clinical, serological or genetic markers associated with inpatient resource utilization in patients with ulcerative colitis (UC) and Crohn's disease (CD).

METHODS

Patients with IBD with available genetic and serological data who had at least one emergency department visit or hospitalization in a 3-year period were included. The primary outcome measure was HRU, as measured by the All Patient Refined Diagnosis Related Group classification system. Univariate and multivariate linear and logistic regression models were used to identify the associations with HRU.

RESULTS

Altogether 858 (562 CD and 296 UC) patients were included. Anti-CBir1 seropositivity (P = 0.002, effect size [ES]: 0.762, 95% confidence interval [CI] 0.512-1.012) and low socioeconomic status (P = 0.005, ES: 1.620 [95% CI 1.091-2.149]) were independently associated with a high HRU. CD diagnosis (P = 0.006, ES: -0.701 [95% CI -0.959 to -0.443]) was independently associated with a low inpatient HRU.

CONCLUSION

In patients with IBD who required at least one emergency department visit or hospitalization, anti-CBir1 antibody status may be a useful biomarker of HRU when formulating management strategies to reduce disease complications and resource utilization.

Enhanced Utilization of Induced Pluripotent Stem Cell-Derived Human Intestinal Organoids Using Microengineered Chips

BACKGROUND AND AIMS

Human intestinal organoids derived from induced pluripotent stem cells have tremendous potential to elucidate the intestinal epithelium's role in health and disease, but it is difficult to directly assay these complex structures. This study sought to make this technology more amenable for study by obtaining epithelial cells from induced pluripotent stem cell-derived human intestinal organoids and incorporating them into small microengineered Chips. We then investigated if these cells within the Chip were polarized, had the 4 major intestinal epithelial subtypes, and were biologically responsive to exogenous stimuli.

METHODS

Epithelial cells were positively selected from human intestinal organoids and were incorporated into the Chip. The effect of continuous media flow was examined. Immunocytochemistry and in situ hybridization were used to demonstrate that the epithelial cells were polarized and possessed the major intestinal epithelial subtypes. To assess if the incorporated cells were biologically responsive, Western blot analysis and quantitative polymerase chain reaction were used to assess the effects of interferon (IFN)-γ, and fluorescein isothiocyanate-dextran 4 kDa permeation was used to assess the effects of IFN-γ and tumor necrosis factor-α on barrier function.

RESULTS

The optimal cell seeding density and flow rate were established. The continuous administration of flow resulted in the formation of polarized intestinal folds that contained Paneth cells, goblet cells, enterocytes, and enteroendocrine cells along with transit-amplifying and LGR5⁺ stem cells. Administration of IFN-γ for 1 hour resulted in the phosphorylation of STAT1, whereas exposure for 3 days resulted in a significant upregulation of IFN-γ related genes. Administration of IFN-γ and tumor necrosis factor-α for 3 days resulted in an increase in intestinal permeability.

CONCLUSIONS

We demonstrate that the Intestine-Chip is polarized, contains all the intestinal epithelial subtypes, and is biologically responsive to exogenous stimuli. This represents a more amenable platform to use organoid technology and will be highly applicable to personalized medicine and a wide range of gastrointestinal conditions.

TL1A blocking ameliorates intestinal fibrosis in the T cell transfer model of chronic colitis in mice

Tumor necrosis factor like cytokine 1A (TL1A) is a member of the TNF superfamily. Accumulating evidence demonstrated the importance of TL1A in the pathogenesis of inflammatory bowel disease (IBD) and suggested a potential role of TL1A blocking in IBD therapy. Here we aimed to explore whether the anti-TL1A antibody could ameliorate intestinal inflammation and fibrosis in IBD. A T cell transfer model of chronic colitis was induced by intraperitoneal injection of CD4⁺CD45RB^high naive T cells isolated from either C57BL/6 wild type (WT) mice or LCK-CD2-Tl1a-GFP transgenic (L-Tg) mice into recombinase activating gene-1-deficient (RAG^-/-) mice. The colitis model mice were treated prophylactically or therapeutically with anti-Tl1a antibody or IgG isotype control. Haematoxylin and eosin staining (H&E staining), Masson's trichrome staining (MT staining) and sirius red staining were used to detect histopathological changes in colonic tissue; immunohistochemical staining was used to detect the expressions of collagen I, collagen III, TIMP1, vimentin, α-SMA and TGF-β1/Smad3. Results showed that anti-Tl1a antibody could reduce intestinal inflammation and fibrosis by inhibiting the activation of intestinal fibroblasts and reducing the collagen synthesis in the T cell transfer model of chronic colitis. The mechanism may be related to the inhibition of TGF-1/Smad3 signaling pathway.

Association of Ribonuclease T2 Gene Polymorphisms With Decreased Expression and Clinical Characteristics of Severity in Crohn's Disease

BACKGROUND & AIMS

Variants in the tumor necrosis factor superfamily member 15 gene (TNFSF15, also called TL1A) have been associated with risk for inflammatory bowel disease (IBD). TL1A affects expression of multiple cytokines to promote mucosal inflammation. Little is known about the TL1A-response pathways that regulate cytokine expression. We investigated T-cell gene expression patterns to determine the mechanisms by which TL1A regulates cytokine production, and whether these associate with outcomes of patients with Crohn's disease (CD).

METHODS

Peripheral T cells isolated from normal donors were cultured with TL1A. We performed gene expression profile analysis by RNA sequencing of subsets of interferon gamma (IFNG)-producing and non-producing cells purified by flow cytometry. Unsupervised hierarchical clustering analysis was used to identify gene expression differences between these subsets. Ribonuclease T2 gene (RNASET2) expression and methylation were assessed by quantitative trait loci analyses. Clinical characteristics of patients (complications, resistance to therapy, and recurrence time) were associated with single nucleotide polymorphisms in RNASET2. We performed motif screening to identify polymorphisms that disrupt transcription factor binding sites. Levels of RNASET2 were knocked down with small interfering RNA in CD4⁺ T cells and the effect on protein expression was determined by proteomic analysis and cytokine production. Cell aggregation was measured by flow cytometry.

RESULTS

We identified 764 genes with at least a 2-fold difference in TL1A-mediated expression between IFNG-secreting and non-secreting T cells (P < 1 × 10^-5). Many of these genes were located near IBD susceptibility variants. RNASET2 was the only IBD risk-associated gene with >5-fold down-regulation in the IFNG-secreting subset. RNASET2 disease risk variants were associated with decreased expression in peripheral and mucosal tissues and DNA hypermethylation in CD patients requiring surgical intervention. RNASET2 disease risk variants were associated in CD patients with more complicated disease or resistance to therapy, defined in part by failed response to treatment, increased length of intestinal resection, shorter time to repeat surgery, and high Rutgeerts score (>2) in postoperative endoscopy. The RNASET2 variant rs2149092 was predicted to disrupt a consensus binding site for the transcription factor ETS within an enhancer region. Expression of RNASET2 correlated with expression of ETS. RNASET2 knockdown in T cells increased expression of IFNG and intercellular adhesion molecule 1 (ICAM1) and induced T-cell aggregation. A blocking antibody against (ILFA1), disrupting the lymphocyte function-associated antigen 1-intercellular adhesion molecule 1 interaction, reduced T-cell production of IFNG.

CONCLUSIONS

We identified decreased expression of RNASET2 as a component of TL1A-mediated increase in production of IFNG and as a potential biomarker for patients with severe CD. Further study of the role of RNASET2 in regulating mucosal inflammation may lead to development of novel therapeutic targets.

Re: Genome-Wide Association Study Identifies African-Specific Susceptibility Loci in African Americans With Inflammatory Bowel Disease

BACKGROUND & AIMS

The inflammatory bowel diseases (IBD) ulcerative colitis (UC) and Crohn’s disease (CD) cause significant morbidity and are increasing in prevalence among all populations, including African Americans. More than 200 susceptibility loci have been identified in populations of predominantly European ancestry, but few loci have been associated with IBD in other ethnicities.

METHODS

We performed 2 high-density, genome-wide scans comprising 2345 cases of African Americans with IBD (1646 with CD, 583 with UC, and 116 inflammatory bowel disease unclassified) and 5002 individuals without IBD (controls, identified from the Health Retirement Study and Kaiser Permanente database). Single-nucleotide polymorphisms (SNPs) associated at P < 5.0 × 10⁻⁸ in meta-analysis with a nominal evidence (P < .05) in each scan were considered to have genome-wide significance.

RESULTS

We detected SNPs at HLA-DRB1, and African-specific SNPs at ZNF649 and LSAMP, with associations of genome-wide significance for UC. We detected SNPs at USP25 with associations of genome-wide significance for IBD. No associations of genome-wide significance were detected for CD. In addition, 9 genes previously associated with IBD contained SNPs with significant evidence for replication (P < 1.6 × 10⁻⁶): ADCY3, CXCR6, HLA-DRB1 to HLA-DQA1 (genome-wide signifi-cance on conditioning), IL12B, PTGER4, and TNC for IBD; IL23R, PTGER4, and SNX20 (in strong linkage disequilibrium with NOD2) for CD; and KCNQ2 (near TNFRSF6B) for UC. Several of these genes, such as TNC (near TNFSF15), CXCR6, and genes associated with IBD at the HLA locus, contained SNPs with unique association patterns with African-specific alleles.

CONCLUSIONS

We performed a genome-wide association study of African Americans with IBD and identified loci associated with UC in only this population; we also replicated IBD, CD, and UC loci identified in European populations. The detection of variants associated with IBD risk in only people of African descent demonstrates the importance of studying the genetics of IBD and other complex diseases in populations beyond those of European ancestry.

The TNF family member TL1A induces IL-22 secretion in committed human Th17 cells via IL-9 induction

TL1A contributes to the pathogenesis of several chronic inflammatory diseases, including those of the bowel by enhancing TH1, TH17, and TH2 responses. TL1A mediates a strong costimulation of these TH subsets, particularly of mucosal CCR9+ T cells. However, the signaling pathways that TL1A induces in different TH subsets are incompletely understood. We investigated the function of TL1A on human TH17 cells. TL1A, together with TGF-β, IL-6, and IL-23, enhanced the secretion of IL-17 and IFN-γ from human CD4+ memory T cells. TL1A induced expression of the transcription factors BATF and T-bet that correlated with the secretion of IL-17 and IFN-γ. In contrast, TL1A alone induced high levels of IL-22 in memory CD4+ T cells and committed TH17 cells. However, TL1A did not enhance expression of IL-17A in TH17 cells. Expression of the transcription factor aryl hydrocarbon receptor, which regulates the expression of IL-22 was not affected by TL1A. Transcriptome analysis of TH17 cells revealed increased expression of IL-9 in response to TL1A. Blocking IL-9 receptor antibodies abrogated TL1A-induced IL-22 secretion. Furthermore, TL1A increased IL-9 production by peripheral TH17 cells isolated from patients with Crohn's disease. These data suggest that TL1A differentially induces expression of TH17 effector cytokines IL-17, -9, and -22 and provides a potential target for therapeutic intervention in TH17-driven chronic inflammatory diseases.

Defective ATG16L1-mediated removal of IRE1α drives Crohn's disease-like ileitis

ATG16L1^T300A, a major risk polymorphism in Crohn's disease (CD), causes impaired autophagy, but it has remained unclear how this predisposes to CD. In this study, we report that mice with Atg16l1 deletion in intestinal epithelial cells (IECs) spontaneously develop transmural ileitis phenocopying ileal CD in an age-dependent manner, driven by the endoplasmic reticulum (ER) stress sensor IRE1α. IRE1α accumulates in Paneth cells of Atg16l1^ΔIEC mice, and humans homozygous for ATG16L1^T300A exhibit a corresponding increase of IRE1α in intestinal epithelial crypts. In contrast to a protective role of the IRE1β isoform, hyperactivated IRE1α also drives a similar ileitis developing earlier in life in Atg16l1;Xbp1^ΔIEC mice, in which ER stress is induced by deletion of the unfolded protein response transcription factor XBP1. The selective autophagy receptor optineurin interacts with IRE1α, and optineurin deficiency amplifies IRE1α levels during ER stress. Furthermore, although dysbiosis of the ileal microbiota is present in Atg16l1;Xbp1^ΔIEC mice as predicted from impaired Paneth cell antimicrobial function, such structural alteration of the microbiota does not trigger ileitis but, rather, aggravates dextran sodium sulfate-induced colitis. Hence, we conclude that defective autophagy in IECs may predispose to CD ileitis via impaired clearance of IRE1α aggregates during ER stress at this site.

Myeloid ATG16L1 Facilitates Host-Bacteria Interactions in Maintaining Intestinal Homeostasis

Intact ATG16L1 plays an essential role in Paneth cell function and intestinal homeostasis. However, the functional consequences of ATG16L1 deficiency in myeloid cells, particularly macrophages, are not fully characterized. We generated mice with Atg16l1 deficiency in myeloid and dendritic cells and showed that mice with myeloid Atg16l1 deficiency had exacerbated colitis in two acute and one chronic model of colitis with increased proinflammatory to anti-inflammatory macrophage ratios, production of proinflammatory cytokines, and numbers of IgA-coated intestinal microbes. Mechanistic analyses using primary murine macrophages showed that Atg16l1 deficiency led to increased reactive oxygen species production, impaired mitophagy, reduced microbial killing, impaired processing of MHC class II Ags, and altered intracellular trafficking to the lysosomal compartments. Increased production of reactive oxygen species and reduced microbial killing may be general features of the myeloid compartment, as they were also observed in Atg16l1-deficient primary murine neutrophils. A missense polymorphism (Thr³⁰⁰Ala) in the essential autophagy gene ATG16L1 is associated with Crohn disease (CD). Previous studies showed that this polymorphism leads to enhanced cleavage of ATG16L1 T300A protein and thus reduced autophagy. Similar findings were shown in primary human macrophages from controls and a population of CD patients carrying the Atg16l1 T300A risk variant and who were controlled for NOD2 CD-associated variants. This study revealed that ATG16L1 deficiency led to alterations in macrophage function that contribute to the severity of CD.

Genome-Wide Association Study Identifies African-Specific Susceptibility Loci in African Americans With Inflammatory Bowel Disease

BACKGROUND & AIMS

The inflammatory bowel diseases (IBD) ulcerative colitis (UC) and Crohn's disease (CD) cause significant morbidity and are increasing in prevalence among all populations, including African Americans. More than 200 susceptibility loci have been identified in populations of predominantly European ancestry, but few loci have been associated with IBD in other ethnicities.

METHODS

We performed 2 high-density, genome-wide scans comprising 2345 cases of African Americans with IBD (1646 with CD, 583 with UC, and 116 inflammatory bowel disease unclassified) and 5002 individuals without IBD (controls, identified from the Health Retirement Study and Kaiser Permanente database). Single-nucleotide polymorphisms (SNPs) associated at P < 5.0 × 10^-8 in meta-analysis with a nominal evidence (P < .05) in each scan were considered to have genome-wide significance.

RESULTS

We detected SNPs at HLA-DRB1, and African-specific SNPs at ZNF649 and LSAMP, with associations of genome-wide significance for UC. We detected SNPs at USP25 with associations of genome-wide significance for IBD. No associations of genome-wide significance were detected for CD. In addition, 9 genes previously associated with IBD contained SNPs with significant evidence for replication (P < 1.6 × 10^-6): ADCY3, CXCR6, HLA-DRB1 to HLA-DQA1 (genome-wide significance on conditioning), IL12B,PTGER4, and TNC for IBD; IL23R, PTGER4, and SNX20 (in strong linkage disequilibrium with NOD2) for CD; and KCNQ2 (near TNFRSF6B) for UC. Several of these genes, such as TNC (near TNFSF15), CXCR6, and genes associated with IBD at the HLA locus, contained SNPs with unique association patterns with African-specific alleles.

CONCLUSIONS

We performed a genome-wide association study of African Americans with IBD and identified loci associated with UC in only this population; we also replicated IBD, CD, and UC loci identified in European populations. The detection of variants associated with IBD risk in only people of African descent demonstrates the importance of studying the genetics of IBD and other complex diseases in populations beyond those of European ancestry.

A Randomized, Double-Blind, Placebo-Controlled Phase 2 Study of Brodalumab in Patients With Moderate-to-Severe Crohn's Disease

OBJECTIVES

To assess the safety and efficacy of brodalumab, a human anti-interleukin-17 receptor monoclonal antibody, in patients with moderate-to-severe Crohn's disease (CD).

METHODS

Phase 2, randomized, double-blind, placebo-controlled, dose-ranging study in patients with moderate-to-severe CD and evidence of active inflammation. Patients were randomized 1:1:1:1 to receive brodalumab (210, 350, or 700 mg at baseline and week 4) or placebo. The primary end point was proportion of patients achieving Crohn's disease activity index (CDAI) remission (≤150) at week 6. Secondary end points included proportion of patients with CDAI response (reduction from baseline of ≥100) at week 6 and change from baseline in CDAI at week 6.

RESULTS

The study was terminated early based on an imbalance in worsening CD in active treatment groups. At the time of termination, 130 patients had been randomized. At week 6, remission rates were 3% (210 mg), 15% (350 mg), 9% (700 mg), and 3% (placebo) and CDAI response occurred in 16% (210 mg), 27% (350 mg), 15% (700 mg), and 13% (placebo) of patients. Mean change in CDAI at week 6 was -8.7 (95.3) (210 mg), -35.4 (105.6) (350 mg), -0.6 (105.9) (700 mg), and -28.2 (86.0) (placebo). Besides worsening of CD, overall incidences of adverse events were similar across treatment groups.

CONCLUSIONS

Treatment with brodalumab resulted in a disproportionate number of cases of worsening CD in patients with active CD and no evidence of meaningful efficacy. These analyses did not suggest additional safety risks of brodalumab beyond worsening of CD symptoms in patients with active CD.

A Pleiotropic Missense Variant in SLC39A8 Is Associated With Crohn's Disease and Human Gut Microbiome Composition

BACKGROUND & AIMS

Genome-wide association studies have identified 200 inflammatory bowel disease (IBD) loci, but the genetic architecture of Crohn's disease (CD) and ulcerative colitis remain incompletely defined. Here, we aimed to identify novel associations between IBD and functional genetic variants using the Illumina ExomeChip (San Diego, CA).

METHODS

Genotyping was performed in 10,523 IBD cases and 5726 non-IBD controls. There were 91,713 functional single-nucleotide polymorphism loci in coding regions analyzed. A novel identified association was replicated further in 2 independent cohorts. We further examined the association of the identified single-nucleotide polymorphism with microbiota from 338 mucosal lavage samples in the Mucosal Luminal Interface cohort measured using 16S sequencing.

RESULTS

We identified an association between CD and a missense variant encoding alanine or threonine at position 391 in the zinc transporter solute carrier family 39, member 8 protein (SLC39A8 alanine 391 threonine, rs13107325) and replicated the association with CD in 2 replication cohorts (combined meta-analysis P = 5.55 × 10(-13)). This variant has been associated previously with distinct phenotypes including obesity, lipid levels, blood pressure, and schizophrenia. We subsequently determined that the CD risk allele was associated with altered colonic mucosal microbiome composition in both healthy controls (P = .009) and CD cases (P = .0009). Moreover, microbes depleted in healthy carriers strongly overlap with those reduced in CD patients (P = 9.24 × 10(-16)) and overweight individuals (P = 6.73 × 10(-16)).

CONCLUSIONS

Our results suggest that an SLC39A8-dependent shift in the gut microbiome could explain its pleiotropic effects on multiple complex diseases including CD.

Gene-microbiota interactions contribute to the pathogenesis of inflammatory bowel disease

Inflammatory bowel disease (IBD) is associated with risk variants in the human genome and dysbiosis of the gut microbiome, though unifying principles for these findings remain largely undescribed. The human commensal Bacteroides fragilis delivers immunomodulatory molecules to immune cells via secretion of outer membrane vesicles (OMVs). We reveal that OMVs require IBD-associated genes, ATG16L1 and NOD2, to activate a noncanonical autophagy pathway during protection from colitis. ATG16L1-deficient dendritic cells do not induce regulatory T cells (T(regs)) to suppress mucosal inflammation. Immune cells from human subjects with a major risk variant in ATG16L1 are defective in T(reg) responses to OMVs. We propose that polymorphisms in susceptibility genes promote disease through defects in "sensing" protective signals from the microbiome, defining a potentially critical gene-environment etiology for IBD.

Cytokine and anti-cytokine therapies in prevention or treatment of fibrosis in IBD

The frequency of fibrosing Crohn's disease (CD) is significant, with approximately 40% of CD patients with ileal disease developing clinically apparent strictures throughout their lifetime. Although strictures may be subdivided into fibrotic, inflammatory, or mixed forms, despite immunosuppressive therapy in CD patients in the form of steroids or immunomodulators, the frequency of fibrostenosing complications has still remained significant. A vast number of genetic and epigenetic variables are thought to contribute to fibrostenosing disease, including those that affect cytokine biology, and therefore highlight the complexity of disease, but also shed light on targetable pathways. Exclusively targeting fibrosis may be difficult, however, because of the relatively slow evolution of fibrosis in CD, and the potential adverse effects of inhibiting pathways involved in tissue repair and mucosal healing. Acknowledging these caveats, cytokine-targeted therapy has become the mainstay of treatment for many inflammatory conditions and is being evaluated for fibrotic disorders. The question of whether anti-cytokine therapy will prove useful for intestinal fibrosis is, therefore, acutely relevant. This review will highlight some of the current therapeutics targeting cytokines involved in fibrosis.

A validated web-based tool to display individualised Crohn's disease predicted outcomes based on clinical, serologic and genetic variables

BACKGROUND

Early treatment for Crohn's disease (CD) with immunomodulators and/or anti-TNF agents improves outcomes in comparison to a slower 'step up' algorithm. However, there remains a limited ability to identify those who would benefit most from early intensive therapy.

AIM

To develop a validated, individualised, web-based tool for patients and clinicians to visualise individualised risks for developing Crohn's disease complications.

METHODS

A well-characterised cohort of adult patients with CD was analysed. Available data included: demographics; clinical characteristics; serologic immune responses; NOD2 status; time from diagnosis to complication; and medication exposure. Cox proportional analyses were performed to model the probability of developing a CD complication over time. The Cox model was validated externally in two independent CD cohorts. Using system dynamics analysis (SDA), these results were transformed into a simple graphical web-based display to show patients their individualised probability of developing a complication over a 3-year period.

RESULTS

Two hundered and forty three CD patients were included in the final model of which 142 experienced a complication. Significant variables in the multivariate Cox model included small bowel disease (HR 2.12, CI 1.05-4.29), left colonic disease (HR 0.73, CI 0.49-1.09), perianal disease (HR 4.12, CI 1.01-16.88), ASCA (HR 1.35, CI 1.16-1.58), Cbir (HR 1.29, CI 1.07-1.55), ANCA (HR 0.77, CI 0.62-0.95), and the NOD2 frameshift mutation/SNP13 (HR 2.13, CI 1.33-3.40). The Harrell's C (concordance index for predictive accuracy of the model) = 0.73. When applied to the two external validation cohorts (adult n = 109, pediatric n = 392), the concordance index was 0.73 and 0.75, respectively, for adult and pediatric patients.

CONCLUSIONS

A validated, web-based tool has been developed to display an individualised predicted outcome for adult patients with Crohn's disease based on clinical, serologic and genetic variables. This tool can be used to help providers and patients make personalised decisions about treatment options.

Ocular Manifestations in Inflammatory Bowel Disease Are Associated with Other Extra-intestinal Manifestations, Gender, and Genes Implicated in Other Immune-related Traits

BACKGROUND

There has been considerable progress in identifying inflammatory bowel disease [IBD] susceptibility genes but little progress in examining the role of genetic variation in the development of the extra-intestinal manifestations [EIMs] of IBD. This study identified clinical, serological, and genetic factors associated with ocular EIMs [O-EIMs] in IBD.

METHODS

We performed a retrospective case-control study of IBD patients, comparing those with and without O-EIMs using the Cedars-Sinai IBD Research Repository and the NIDDK IBD Genetics Consortium Repository. Genotyping was performed using Illumina whole genome platforms.

RESULTS

In all, 124 cases and 3328 controls with available clinical data were identified; 103 cases and 2808 controls had genetic data available. Erythema nodosum and peripheral arthritis particularly were common in patients with O-EIMs [p = 2.77 x 10(-13) and p = 2.58 x 10(-13), respectively] with increasing odds ratios for O-EIMs with each additional non-ocular-EIM [for ≥ 2 EIMs, odds ratio 14.72]. Nominal association with O-EIMs was observed at several known IBD susceptibility single nuclear polymorphisms. One locus, containing RBM19, achieved genome-wide level of significance for association with O-EIMs.

CONCLUSIONS

In IBD, O-EIMs co-occur with musculoskeletal and skin manifestations and, in this study, are nominally associated with known IBD loci. Additional cohorts are needed to verify these results and identify additional genes.

Characterization of genetic loci that affect susceptibility to inflammatory bowel diseases in African Americans

BACKGROUND & AIMS

Inflammatory bowel disease (IBD) has familial aggregation in African Americans (AAs), but little is known about the molecular genetic susceptibility. Mapping studies using the Immunochip genotyping array expand the number of susceptibility loci for IBD in Caucasians to 163, but the contribution of the 163 loci and European admixture to IBD risk in AAs is unclear. We performed a genetic mapping study using the Immunochip to determine whether IBD susceptibility loci in Caucasians also affect risk in AAs and identify new associated loci.

METHODS

We recruited AAs with IBD and without IBD (controls) from 34 IBD centers in the United States; additional controls were collected from 4 other Immunochip studies. Association and admixture loci were mapped for 1088 patients with Crohn's disease, 361 with ulcerative colitis, 62 with IBD type unknown, and 1797 controls; 130,241 autosomal single-nucleotide polymorphisms (SNPs) were analyzed.

RESULTS

The strongest associations were observed between ulcerative colitis and HLA rs9271366 (P = 7.5 × 10(-6)), Crohn's disease and 5p13.1 rs4286721 (P = 3.5 × 10(-6)), and IBD and KAT2A rs730086 (P = 2.3 × 10(-6)). Additional suggestive associations (P < 4.2 × 10(-5)) were observed between Crohn's disease and IBD and African-specific SNPs in STAT5A and STAT3; between IBD and SNPs in IL23R, IL12B, and C2orf43; and between ulcerative colitis and SNPs near HDAC11 and near LINC00994. The latter 3 loci have not been previously associated with IBD, but require replication. Established Caucasian associations were replicated in AAs (P < 3.1 × 10(-4)) at NOD2, IL23R, 5p15.3, and IKZF3. Significant admixture (P < 3.9 × 10(-4)) was observed for 17q12-17q21.31 (IZKF3 through STAT3), 10q11.23-10q21.2, 15q22.2-15q23, and 16p12.2-16p12.1. Network analyses showed significant enrichment (false discovery rate <1 × 10(-5)) in genes that encode members of the JAK-STAT, cytokine, and chemokine signaling pathways, as well those involved in pathogenesis of measles.

CONCLUSIONS

In a genetic analysis of 3308 AA IBD cases and controls, we found that many variants associated with IBD in Caucasians also showed association evidence with these diseases in AAs; we also found evidence for variants and loci not previously associated with IBD. The complex genetic factors that determine risk for or protection against IBD in different populations require further study.

Long-term outcomes of thalidomide in refractory Crohn's disease

BACKGROUND

Several open-label and retrospective studies have indicated that thalidomide may be beneficial in patients with refractory Crohn's disease (CD).

AIM

To report our long-term experience with the use of thalidomide for adults with refractory Crohn's disease.

METHODS

We conducted a retrospective study of long-term clinical and safety outcomes among adults treated with thalidomide for refractory Crohn's disease. Response was defined as a clinician's assessment of improvement after at least 7 days treatment of one or more of the following: bowel movement frequency, fistula output, rectal bleeding, abdominal pain, extraintestinal manifestations, or well-being. Remission required all of the following: <3 stools/day, no bleeding, abdominal pain or extraintestinal manifestations and increased well-being.

RESULTS

Thirty-seven adults with refractory Crohn's disease were treated with thalidomide for a median of 4.4 months and followed up for a median of 58 months. Clinical response and remission rates were 54% and 19%, respectively. About 40% of patients were able to stop steroids. Response rates were higher for those treated with more than 50 mg/day (85%) than for those treated with a maximum of 50 mg/day (40%; P = 0.01). An adverse event occurred in 68% of patients. Approximately one-third of patients (38%) experienced neuropathy.

CONCLUSIONS

Thalidomide appears to be safe and effective in some patients with refractory Crohn's disease. Although side effects may limit long-term use, thalidomide has potential to induce significant clinical responses.

Microbiota activation and regulation of innate and adaptive immunity

The human host has coevolved with the collective of bacteria species, termed microbiota, in a complex fashion that affects both innate and adaptive immunity. Differential regulation of regulatory T-cell and effector T-cell responses are a direct result of specific microbial species present within the gut, and this relationship is subject to dysregulation during inflammation and disease. The microbiota varies widely between individuals and has a profound effect on how one reacts to various environmental stimuli, particularly if a person is genetically predisposed to an immune-mediated inflammatory disorder such as inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC). Approximately, half of all CD patients have elevated antibodies to CBir1, a microbiota flagellin common to mice and humans, demonstrating flagellins as immunodominant antigens in the intestines. This review focuses on the use of flagellins as probes to study microbiota-specific responses in the context of health and disease as well as probes of innate and adaptive responses employed by the host to deal with the overwhelming bacterial presence of the microbiota.

Inhibition of a novel fibrogenic factor Tl1a reverses established colonic fibrosis

Intestinal fibrostenosis is among the hallmarks of severe Crohn's disease. Patients with certain TNFSF15 (gene name for TL1A) variants over-express TL1A and have a higher risk of developing strictures in the small intestine. In addition, sustained Tl1a expression in mice leads to small and large intestinal fibrostenosis under colitogenic conditions. The aim of this study was to determine whether established murine colonic fibrosis could be reversed with Tl1a antibody (Ab). Treatment with neutralizing Tl1a Ab reversed colonic fibrosis back to the original pre-inflamed levels, potentially as a result of lowered expression of connective tissue growth factor, Il31Ra, transforming growth factor β1 and insulin-like growth factor-1. In addition, blocking Tl1a function by either neutralizing Tl1a Ab or deletion of death domain receptor 3 (Dr3) reduced the number of fibroblasts and myofibroblasts, the primary cell types that mediate tissue fibrosis. Primary intestinal myofibroblasts expressed Dr3 and functionally responded to direct Tl1a signaling by increasing collagen and Il31Ra expression. These data demonstrated a direct role for TL1A-DR3 signaling in tissue fibrosis and that modulation of TL1A-DR3 signaling could inhibit gut fibrosis.

Reliable generation of induced pluripotent stem cells from human lymphoblastoid cell lines

Patient-specific induced pluripotent stem cells (iPSCs) hold great promise for many applications, including disease modeling to elucidate mechanisms involved in disease pathogenesis, drug screening, and ultimately regenerative medicine therapies. A frequently used starting source of cells for reprogramming has been dermal fibroblasts isolated from skin biopsies. However, numerous repositories containing lymphoblastoid cell lines (LCLs) generated from a wide array of patients also exist in abundance. To date, this rich bioresource has been severely underused for iPSC generation. We first attempted to create iPSCs from LCLs using two existing methods but were unsuccessful. Here we report a new and more reliable method for LCL reprogramming using episomal plasmids expressing pluripotency factors and p53 shRNA in combination with small molecules. The LCL-derived iPSCs (LCL-iPSCs) exhibited identical characteristics to fibroblast-derived iPSCs (fib-iPSCs), wherein they retained their genotype, exhibited a normal pluripotency profile, and readily differentiated into all three germ-layer cell types. As expected, they also maintained rearrangement of the heavy chain immunoglobulin locus. Importantly, we also show efficient iPSC generation from LCLs of patients with spinal muscular atrophy and inflammatory bowel disease. These LCL-iPSCs retained the disease mutation and could differentiate into neurons, spinal motor neurons, and intestinal organoids, all of which were virtually indistinguishable from differentiated cells derived from fib-iPSCs. This method for reliably deriving iPSCs from patient LCLs paves the way for using invaluable worldwide LCL repositories to generate new human iPSC lines, thus providing an enormous bioresource for disease modeling, drug discovery, and regenerative medicine applications.