TL1A: A model for a precision medicine approach in the treatment of Crohn's disease and ulcerative colitis.

Inflammatory bowel disease (IBD) is a collective term for chronic inflammatory diseases of the intestinal tract. The term IBD encompasses two main forms, Crohn's disease (CD) and Ulcerative colitis (UC). CD is characterized by inflammation throughout the length of the gut, especially the ileum and colon, and is often complicated with fistulae and/or intestinal strictures.

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

Introduction: The maintenance of intestinal homeostasis depends on a complex interaction between the immune system, intestinal epithelial barrier, and microbiota. Alteration in one of these components could lead to the development of inflammatory bowel diseases (IBD). Variants within the autophagy gene have been implicated in susceptibility and severity of Crohn's disease (CD).

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).

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).

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.

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.

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 ().

Design: Immunochip-based meta-analysis on 4056 pCD and 11 088 patients with CD from three independent cohorts was performed.

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.

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.

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.

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 mice developed metabolic syndrome and have altered localization of tight junction proteins in intestinal epithelial cells leading to increased intestinal permeability.

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.

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.

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.

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.

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.

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.

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].

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.

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.

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.

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

Angiotensin-Converting Enzyme 2 ( ) 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 mRNA in ileum with demographic features that have been associated with poor outcomes in COVID-19 including age and raised BMI. was downregulated in CD compared to controls in independent cohorts.

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 model of intestinal permeability using induced pluripotent stem cell (iPSC)-derived human intestinal organoids (HIOs) and human colonic organoids (HCOs) to study barrier dysfunction.

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.

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.