Five-Year Efficacy and Safety of Ustekinumab Treatment in Crohn's Disease: The IM-UNITI Trial.

BACKGROUND & AIMS: The IM-UNITI study and long-term extension (LTE) evaluated the long-term efficacy, safety, and immunogenicity of subcutaneous ustekinumab maintenance therapy in patients with Crohn's disease. Here, we report the final results of IM-UNITI LTE through 5 years. METHODS: Patients completing safety and efficacy evaluations at week 44 of the maintenance study were eligible to participate in the LTE and continue the treatment they were receiving. Unblinding occurred after completion of maintenance study analyses (August 2015), and patients receiving placebo were discontinued from the study after unblinding. No dose adjustment occurred in the LTE. Efficacy assessments were conducted every 12 weeks until unblinding and at dosing visits thereafter through week 252. Serum ustekinumab concentrations and antidrug antibodies were evaluated through weeks 252 and 272, respectively. RESULTS: Using an intent-to-treat analysis of all patients randomized to ustekinumab at maintenance baseline, 34.4% of patients in the every-8-weeks group and 28.7% in the every-12-weeks group were in clinical remission at week 252. Corresponding remission rates among patients who entered the LTE were 54.9% and 45.2%. Overall, adverse event rates (per 100 patient-years) from maintenance week 0 through the final visit generally were similar in the placebo and combined ustekinumab groups for all adverse events (440.3 vs 327.6), serious adverse events (19.3 vs 17.5), infections (99.8 vs 93.8), and serious infections (3.9 vs 3.4). Serum ustekinumab concentrations were maintained throughout the LTE. Antidrug antibodies occurred in 5.8% of patients who received ustekinumab during induction and maintenance and continued in the LTE. CONCLUSIONS: Patients receiving subcutaneous ustekinumab maintained clinical remission through 5 years. No new safety signals were observed. ClinicalTrials.gov number NCT01369355.

Maintenance Golimumab Treatment in Pediatric UC Patients With Moderately to Severely Active UC: PURSUIT PEDS PK Long-Term Study Results.

Background: Long-term safety, pharmacokinetics, and efficacy of open-label golimumab therapy in children with moderate-severe ulcerative colitis were evaluated. Methods: Week-6 golimumab responders (Mayo score decrease of ≥30% and ≥3 points from baseline, rectal bleeding subscore of 0/1 or ≥1 decrease from baseline) entered the long-term extension at week 14 and received maintenance therapy (subcutaneous, q4w). Patients ≥45 kg could receive at-home treatments at week 18. Pharmacokinetic, safety, and efficacy results were summarized through week 126 (2 years). Results: Among 35 enrolled children, 21 (60%) responded at week 6 and 20 entered the long-term extension (median age of 14.5 years and median weight of 46.1 kg). Eleven of 20 patients (55%) completed 2 years of treatment. No anaphylactic or serum sickness-like reactions, opportunistic infections, malignancies, tuberculosis, or deaths occurred. The safety profile of golimumab from weeks 14 through 126 and that observed through week 14 was generally consistent. Median trough golimumab concentrations in evaluable patients were consistent from weeks 14 (1.39, interquartile range 0.67-3.60) through 102 (1.18, 0.78-2.16), but higher at week 110 (4.10, 1.30-4.81). The incidence of antigolimumab antibodies increased from 10% (2/20) at week 30 to 25.0% (5/20) at week 126; 1 patient had neutralizing antibodies. At week 110, 50% (10/20) of patients were in remission (ie, Pediatric Ulcerative Colitis Activity Index <10). Among all enrolled patients, 28.6% (10/35) achieved remission at week 110. Conclusions: Among children with ulcerative colitis who initially responded to golimumab induction and received q4w maintenance treatment in the long-term extension, 50% showed continued clinical benefit through 2 years. No new safety signals were observed.

KLF4 activates NFκB signaling and esophageal epithelial inflammation via the Rho-related GTP-binding protein RHOF.

Understanding the regulatory mechanisms within esophageal epithelia is essential to gain insight into the pathogenesis of esophageal diseases, which are among the leading causes of morbidity and mortality throughout the world. The zinc-finger transcription factor Krüppel-like factor (KLF4) is implicated in a large number of cellular processes, such as proliferation, differentiation, and inflammation in esophageal epithelia. In murine esophageal epithelia, Klf4 overexpression causes chronic inflammation which is mediated by activation of NFκB signaling downstream of KLF4, and this esophageal inflammation produces epithelial hyperplasia and subsequent esophageal squamous cell cancer. Yet, while NFκB activation clearly promotes esophageal inflammation, the mechanisms by which NFκB signaling is activated in esophageal diseases are not well understood. Here, we demonstrate that the Rho-related GTP-binding protein RHOF is activated by KLF4 in esophageal keratinocytes, leading to the induction of NFκB signaling. Moreover, RHOF is required for NFκB activation by KLF4 in esophageal keratinocytes and is also important for esophageal keratinocyte proliferation and migration. Finally, we find that RHOF is upregulated in eosinophilic esophagitis, an important esophageal inflammatory disease in humans. Thus, RHOF activation of NFκB in esophageal keratinocytes provides a potentially important and clinically-relevant mechanism for esophageal inflammation and inflammation-mediated esophageal squamous cell cancer.

Unintended consequences of changes to lung allocation policy.

Organ allocation for transplantation aims to balance the principles of justice and medical utility to optimally utilize a scarce resource. To address practical considerations, the United States is divided into 58 donor service areas (DSA), each constituting the first unit of allocation. In November 2017, in response to a lawsuit in New York, an emergency action change to lung allocation policy replaced the DSA level of allocation for donor lungs with a 250 nautical mile circle around the donor hospital. Similar policy changes are being implemented for other organs including heart and liver. Findings from a recent US Department of Health and Human Services report, supplemented with data from our institution, suggest that the emergency policy has not resulted in a change in the type of patients undergoing lung transplantation (LT) or early postoperative outcomes. However, there has been a significant decline in local LT, where donor and recipient are in the same DSA. With procurement teams having to travel greater distances, organ ischemic time has increased and median organ cost has more than doubled. We propose potential solutions for consideration at this critical juncture in the field of transplantation. Policymakers should choose equitable and sustainable access for this lifesaving discipline.

Aspirin prevents NF-κB activation and CDX2 expression stimulated by acid and bile salts in oesophageal squamous cells of patients with Barrett's oesophagus.

OBJECTIVE: In previous studies using oesophageal squamous cells from patients with Barrett's oesophagus (normal oesophageal squamous (NES)-B cells) and from patients without Barrett's oesophagus (NES-G cells), we showed that acid and bile salts induced caudal-related homeobox transcription factor 2 (CDX2) expression only in NES-B cells. CDX2, a transcription factor required to form intestinal epithelium, is a target of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signalling, which can be inhibited by aspirin. We explored mechanisms underlying differences between NES-B and NES-G cells in CDX2 expression and effects of aspirin on that CDX2 expression. DESIGN: We exposed NES-B and NES-G cells to acid and bile salts, with and without aspirin, and evaluated effects on IκB-NF-κB-PKAc complex activation, p65 NF-κB subunit function, and CDX2 expression. RESULTS: In both NES-B and NES-G cells, acid and bile salts activated nicotinamide adenine dinucleotide phosphate oxidase to generate H2O2, which activated the IκB-NF-κB-PKAc complex. NES-B cells exhibited higher levels of phosphorylated IκB and p65 and greater NF-κB transcriptional activity than NES-G cells, indicating greater IκB-NF-κB-PKAc complex activation by acid and bile salts in NES-B cells, and p65 siRNA prevented their increased expression of CDX2. Aspirin blocked IκB phosphorylation, p65 nuclear translocation, CDX2 promoter activation and CDX2 expression induced by acid and bile salts in NES-B cells. CONCLUSIONS: Differences between NES-B and NES-G cells in NF-κB activation by acid and bile salts can account for their differences in CDX2 expression, and their CDX2 expression can be blocked by aspirin. These findings might explain why some patients with GORD develop Barrett's oesophagus while others do not, and why aspirin might protect against development of Barrett's oesophagus.

GUCY2C maintains intestinal LGR5+ stem cells by opposing ER stress.

Long-lived multipotent stem cells (ISCs) at the base of intestinal crypts adjust their phenotypes to accommodate normal maintenance and post-injury regeneration of the epithelium. Their long life, lineage plasticity, and proliferative potential underlie the necessity for tight homeostatic regulation of the ISC compartment. In that context, the guanylate cyclase C (GUCY2C) receptor and its paracrine ligands regulate intestinal epithelial homeostasis, including proliferation, lineage commitment, and DNA damage repair. However, a role for this axis in maintaining ISCs remains unknown. Transgenic mice enabling analysis of ISCs (Lgr5-GFP) in the context of GUCY2C elimination (Gucy2c-/- ) were combined with immunodetection techniques and pharmacological treatments to define the role of the GUCY2C signaling axis in supporting ISCs. ISCs were reduced in Gucy2c-/- mice, associated with loss of active Lgr5+ cells but a reciprocal increase in reserve Bmi1+ cells. GUCY2C was expressed in crypt base Lgr5+ cells in which it mediates canonical cyclic (c) GMP-dependent signaling. Endoplasmic reticulum (ER) stress, typically absent from ISCs, was elevated throughout the crypt base in Gucy2c-/- mice. The chemical chaperone tauroursodeoxycholic acid resolved this ER stress and restored the balance of ISCs, an effect mimicked by the GUCY2C effector 8Br-cGMP. Reduced ISCs in Gucy2c-/- mice was associated with greater epithelial injury and impaired regeneration following sub-lethal doses of irradiation. These observations suggest that GUCY2C provides homeostatic signals that modulate ER stress and cell vulnerability as part of the machinery contributing to the integrity of ISCs.

Intestinal Enteroendocrine Lineage Cells Possess Homeostatic and Injury-Inducible Stem Cell Activity.

Several cell populations have been reported to possess intestinal stem cell (ISC) activity during homeostasis and injury-induced regeneration. Here, we explored inter-relationships between putative mouse ISC populations by comparative RNA-sequencing (RNA-seq). The transcriptomes of multiple cycling ISC populations closely resembled Lgr5+ ISCs, the most well-defined ISC pool, but Bmi1-GFP+ cells were distinct and enriched for enteroendocrine (EE) markers, including Prox1. Prox1-GFP+ cells exhibited sustained clonogenic growth in vitro, and lineage-tracing of Prox1+ cells revealed long-lived clones during homeostasis and after radiation-induced injury in vivo. Single-cell mRNA-seq revealed two subsets of Prox1-GFP+ cells, one of which resembled mature EE cells while the other displayed low-level EE gene expression but co-expressed tuft cell markers, Lgr5 and Ascl2, reminiscent of label-retaining secretory progenitors. Our data suggest that the EE lineage, including mature EE cells, comprises a reservoir of homeostatic and injury-inducible ISCs, extending our understanding of cellular plasticity and stemness.

Modeling Esophagitis Using Human Three-Dimensional Organotypic Culture System.

Esophagitis, whether caused by acid reflux, allergic responses, graft-versus-host disease, drugs, or infections, is a common condition of the gastrointestinal tract affecting nearly 20% of the US population. The instigating agent typically triggers an inflammatory response. The resulting inflammation is a risk factor for the development of esophageal strictures, Barrett esophagus, and esophageal adenocarcinoma. Research into the pathophysiology of these conditions has been limited by the availability of animal and human model systems. Three-dimensional organotypic tissue culture (OTC) is an innovative three-dimensional multicellular in vitro platform that recapitulates normal esophageal epithelial stratification and differentiation. We hypothesized that this platform can be used to model esophagitis to better understand the interactions between immune cells and the esophageal epithelium. We found that human immune cells remain viable and respond to cytokines when cultured under OTC conditions. The acute inflammatory environment induced in the OTC significantly affected the overlying epithelium, inducing a regenerative response marked by increased cell proliferation and epithelial hyperplasia. Moreover, oxidative stress from the acute inflammation induced DNA damage and strand breaks in epithelial cells, which could be reversed by antioxidant treatment. These findings support the importance of immune cell-mediated esophageal injury in esophagitis and confirms the utility of the OTC platform to characterize the underlying molecular events in esophagitis.

Mutual reinforcement between telomere capping and canonical Wnt signalling in the intestinal stem cell niche.

Critical telomere shortening (for example, secondary to partial telomerase deficiency in the rare disease dyskeratosis congenita) causes tissue pathology, but underlying mechanisms are not fully understood. Mice lacking telomerase (for example, mTR-/- telomerase RNA template mutants) provide a model for investigating pathogenesis. In such mice, after several generations of telomerase deficiency telomeres shorten to the point of uncapping, causing defects most pronounced in high-turnover tissues including intestinal epithelium. Here we show that late-generation mTR-/- mutants experience marked downregulation of Wnt pathway genes in intestinal crypt epithelia, including crypt base columnar stem cells and Paneth cells, and in underlying stroma. The importance of these changes was revealed by rescue of crypt apoptosis and Wnt pathway gene expression upon treatment with Wnt pathway agonists. Rescue was associated with reduced telomere-dysfunction-induced foci and anaphase bridges, indicating improved telomere capping. Thus a mutually reinforcing feedback loop exists between telomere capping and Wnt signalling, and telomere capping can be impacted by extracellular cues in a fashion independent of telomerase.

Intestinal Enteroids Model Guanylate Cyclase C-Dependent Secretion Induced by Heat-Stable Enterotoxins.

Enterotoxigenic Escherichia coli (ETEC) causes ∼20% of the acute infectious diarrhea (AID) episodes worldwide, often by producing heat-stable enterotoxins (STs), which are peptides structurally homologous to paracrine hormones of the intestinal guanylate cyclase C (GUCY2C) receptor. While molecular mechanisms mediating ST-induced intestinal secretion have been defined, advancements in therapeutics have been hampered for decades by the paucity of disease models that integrate molecular and functional endpoints amenable to high-throughput screening. Here, we reveal that mouse and human intestinal enteroids in three-dimensional ex vivo cultures express the components of the GUCY2C secretory signaling axis. ST and its structural analog, linaclotide, an FDA-approved oral secretagog, induced fluid accumulation quantified simultaneously in scores of enteroid lumens, recapitulating ETEC-induced intestinal secretion. Enteroid secretion depended on canonical molecular signaling events responsible for ETEC-induced diarrhea, including cyclic GMP (cGMP) produced by GUCY2C, activation of cGMP-dependent protein kinase (PKG), and opening of the cystic fibrosis transmembrane conductance regulator (CFTR). Importantly, pharmacological inhibition of CFTR abrogated enteroid fluid secretion, providing proof of concept for the utility of this model to screen antidiarrheal agents. Intestinal enteroids offer a unique model, integrating the GUCY2C signaling axis and luminal fluid secretion, to explore the pathophysiology of, and develop platforms for, high-throughput drug screening to identify novel compounds to prevent and treat ETEC diarrheal disease.

Association Between Germline Mutation in VSIG10L and Familial Barrett Neoplasia.

IMPORTANCE: Esophageal adenocarcinoma and its precursor lesion Barrett esophagus have seen a dramatic increase in incidence over the past 4 decades yet marked genetic heterogeneity of this disease has precluded advances in understanding its pathogenesis and improving treatment. OBJECTIVE: To identify novel disease susceptibility variants in a familial syndrome of esophageal adenocarcinoma and Barrett esophagus, termed familial Barrett esophagus, by using high-throughput sequencing in affected individuals from a large, multigenerational family. DESIGN, SETTING, AND PARTICIPANTS: We performed whole exome sequencing (WES) from peripheral lymphocyte DNA on 4 distant relatives from our multiplex, multigenerational familial Barrett esophagus family to identify candidate disease susceptibility variants. Gene variants were filtered, verified, and segregation analysis performed to identify a single candidate variant. Gene expression analysis was done with both quantitative real-time polymerase chain reaction and in situ RNA hybridization. A 3-dimensional organotypic cell culture model of esophageal maturation was utilized to determine the phenotypic effects of our gene variant. We used electron microscopy on esophageal mucosa from an affected family member carrying the gene variant to assess ultrastructural changes. MAIN OUTCOMES AND MEASURES: Identification of a novel, germline disease susceptibility variant in a previously uncharacterized gene. RESULTS: A multiplex, multigenerational family with 14 members affected (3 members with esophageal adenocarcinoma and 11 with Barrett esophagus) was identified, and whole-exome sequencing identified a germline mutation (S631G) at a highly conserved serine residue in the uncharacterized gene VSIG10L that segregated in affected members. Transfection of S631G variant into a 3-dimensional organotypic culture model of normal esophageal squamous cells dramatically inhibited epithelial maturation compared with the wild-type. VSIG10L exhibited high expression in normal squamous esophagus with marked loss of expression in Barrett-associated lesions. Electron microscopy of squamous esophageal mucosa harboring the S631G variant revealed dilated intercellular spaces and reduced desmosomes. CONCLUSIONS AND RELEVANCE: This study presents VSIG10L as a candidate familial Barrett esophagus susceptibility gene, with a putative role in maintaining normal esophageal homeostasis. Further research assessing VSIG10L function may reveal pathways important for esophageal maturation and the pathogenesis of Barrett esophagus and esophageal adenocarcinoma.

Autophagy levels are elevated in barrett's esophagus and promote cell survival from acid and oxidative stress.

Autophagy is a highly conserved mechanism that is activated during cellular stress. We hypothesized that autophagy may be induced by acid reflux, which causes injury, and inflammation, and therefore, contributes to the pathogenesis of Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC). Currently, the role of autophagy in BE and EAC is poorly studied. We quantitatively define autophagy levels in human BE cell lines, a transgenic mouse model of BE, and human BE, and EAC biopsies. Human non-dysplastic BE had the highest basal number of autophagic vesicles (AVs), while AVs were reduced in normal squamous cells and dysplastic BE cells, and nearly absent in EAC. To demonstrate a functional role for autophagy in BE pathogenesis, normal squamous (STR), non-dysplastic BE (CPA), dysplastic BE (CPD), and EAC (OE19) cell lines were exposed to an acid pulse (pH 3.5) followed by incubation in the presence or absence of chloroquine, an autophagy inhibitor. Acid exposure increased reactive oxygen species (ROS) levels in STR and CPA cells. Chloroquine alone had a small impact on intracellular ROS or cell survival. However, combination of chloroquine with the acid pulse resulted in a significant increase in ROS levels at 6 h in STR and CPA cells, and increased cell death in all cell lines. These findings establish increased numbers of AVs in human BE compared to normal squamous or EAC, and suggest that autophagy functions to improve cell survival after acid reflux injury. Autophagy may thus play a critical role in BE pathogenesis and progression. © 2015 Wiley Periodicals, Inc.

Immature myeloid progenitors promote disease progression in a mouse model of Barrett's-like metaplasia.

Cdx2, an intestine specific transcription factor, is expressed in Barrett's esophagus (BE). We sought to determine if esophageal Cdx2 expression would accelerate the onset of metaplasia in the L2-IL-1ß transgenic mouse model for Barrett's-like metaplasia. The K14-Cdx2::L2-IL-1ß double transgenic mice had half as many metaplastic nodules as control L2-IL-1ß mice. This effect was not due to a reduction in esophageal IL-1ß mRNA levels nor diminished systemic inflammation. The diminished metaplasia was due to an increase in apoptosis in the K14-Cdx2::L2-IL-1ß mice. Fluorescence activated cell sorting of immune cells infiltrating the metaplasia identified a population of CD11b+Gr-1+ cells that are significantly reduced in K14-Cdx2::L2-IL-1ß mice. These cells have features of immature granulocytes and have immune-suppressing capacity. We demonstrate that the apoptosis in K14-Cdx2::L2-IL-1ß mice is CD8+ T cell dependent, which CD11b+Gr-1+ cells are known to inhibit. Lastly, we show that key regulators of CD11b+Gr-1+ cell development, IL-17 and S100A9, are significantly diminished in the esophagus of K14-Cdx2::L2-IL-1ß double transgenic mice. We conclude that metaplasia development in this mouse model for Barrett's-like metaplasia requires suppression of CD8+ cell dependent apoptosis, likely mediated by immune-suppressing CD11b+Gr-1+ immature myeloid cells.

Quality indicators for the management of Barrett's esophagus, dysplasia, and esophageal adenocarcinoma: international consensus recommendations from the American Gastroenterological Association Symposium.

The development of and adherence to quality indicators in gastroenterology, as in all of medicine, is increasing in importance to ensure that patients receive consistent high-quality care. In addition, government-based and private insurers will be expecting documentation of the parameters by which we measure quality, which will likely affect reimbursements. Barrett's esophagus remains a particularly important disease entity for which we should maintain up-to-date guidelines, given its commonality, potentially lethal outcomes, and controversies regarding screening and surveillance. To achieve this goal, a relatively large group of international experts was assembled and, using the modified Delphi method, evaluated the validity of multiple candidate quality indicators for the diagnosis and management of Barrett's esophagus. Several candidate quality indicators achieved >80% agreement. These statements are intended to serve as a consensus on candidate quality indicators for those who treat patients with Barrett's esophagus.

Culturing adult stem cells from mouse small intestinal crypts.

In recent years, the study of primary cells in culture has evolved from an extraphysiological, two-dimensional platform to novel, three-dimensional platforms in which the addition of matrix components and/or supporting cells provide an ex vivo niche. Such studies have provided the basis on which to study more advanced physiological processes in detail, including multilayered, long-term cultures, epithelial-stromal interactions, and stem cell behaviors that more closely recapitulate normal morphology than two-dimensional culture. Various techniques for three-dimensional organotypic culture and crypt culture of primary cells from mouse and human small intestine and colon have been described. These methods have allowed for the study of specific stem cell characteristics, including survival, self-renewal, and long-term growth in culture, as well as the ability to propagate all the appropriate progenitor and postmitotic lineages. These assays have become a widely accepted functional measure of "stemness" and, in combination with lineage-tracing experiments in various genetically engineered mouse models, have been critical in the identification of specific markers of intestinal stem cells. In this protocol we draw upon recently described methods for the isolation and culture of mouse small intestinal enterospheres/enteroids from isolated crypts and/or single cells. Cultures of murine colon epithelium, as well as human small intestine and colon, require additional growth factors not discussed here. The description provided here represents current knowledge, and it is possible, if not likely, that modifications in the future will emerge.

Mechanisms of Barrett's oesophagus: intestinal differentiation, stem cells, and tissue models.

Barrett's oesophagus (BE) is defined as any metaplastic columnar epithelium in the distal oesophagus which replaces normal squamous epithelium and which predisposes to cancer development. It is this second requirement, the predisposition to cancer, which makes this condition both clinically highly relevant and an important area for ongoing research. While BE has been defined pathologically since the 1950's (Allison and Johnstone, Thorax 1955), and identified as a risk factor for esophageal adenocarcinoma since the 1970's (Naef A.P., et al J Thorac Cardiovasc Surg. 1975), our understanding of the molecular events giving rise to this condition remains limited. Herein we will examine what is known about the intestinal features of BE and how well it recapitulates the intestinal epithelium, including stem identity and function. Finally, we will explore laboratory models of this condition presently in use and under development, to identify new insights they may provide into this important clinical condition.

Modeling human gastrointestinal inflammatory diseases using microphysiological culture systems.

Gastrointestinal illnesses are a significant health burden for the US population, with 40 million office visits each year for gastrointestinal complaints and nearly 250,000 deaths. Acute and chronic inflammations are a common element of many gastrointestinal diseases. Inflammatory processes may be initiated by a chemical injury (acid reflux in the esophagus), an infectious agent (Helicobacter pylori infection in the stomach), autoimmune processes (graft versus host disease after bone marrow transplantation), or idiopathic (as in the case of inflammatory bowel diseases). Inflammation in these settings can contribute to acute complaints (pain, bleeding, obstruction, and diarrhea) as well as chronic sequelae including strictures and cancer. Research into the pathophysiology of these conditions has been limited by the availability of primary human tissues or appropriate animal models that attempt to physiologically model the human disease. With the many recent advances in tissue engineering and primary human cell culture systems, it is conceivable that these approaches can be adapted to develop novel human ex vivo systems that incorporate many human cell types to recapitulate in vivo growth and differentiation in inflammatory microphysiological environments. Such an advance in technology would improve our understanding of human disease progression and enhance our ability to test for disease prevention strategies and novel therapeutics. We will review current models for the inflammatory and immunological aspects of Barrett's esophagus, acute graft versus host disease, and inflammatory bowel disease and explore recent advances in culture methodologies that make these novel microphysiological research systems possible.