G9a Modulates Lipid Metabolism in CD4 T Cells to Regulate Intestinal Inflammation.

BACKGROUND & AIMS: Although T-cell intrinsic expression of G9a has been associated with murine intestinal inflammation, mechanistic insight into the role of this methyltransferase in human T-cell differentiation is ill defined, and manipulation of G9a function for therapeutic use against inflammatory disorders is unexplored. METHODS: Human naive T cells were isolated from peripheral blood and differentiated in vitro in the presence of a G9a inhibitor (UNC0642) before being characterized via the transcriptome (RNA sequencing), chromatin accessibility (assay for transposase-accessible chromatin by sequencing), protein expression (cytometry by time of flight, flow cytometry), metabolism (mitochondrial stress test, ultrahigh performance liquid chromatography-tandem mas spectroscopy) and function (T-cell suppression assay). The in vivo role of G9a was assessed using 3 murine models. RESULTS: We discovered that pharmacologic inhibition of G9a enzymatic function in human CD4 T cells led to spontaneous generation of FOXP3+ T cells (G9a-inibitors-T regulatory cells [Tregs]) in vitro that faithfully reproduce human Tregs, functionally and phenotypically. Mechanistically, G9a inhibition altered the transcriptional regulation of genes involved in lipid biosynthesis in T cells, resulting in increased intracellular cholesterol. Metabolomic profiling of G9a-inibitors-Tregs confirmed elevated lipid pathways that support Treg development through oxidative phosphorylation and enhanced lipid membrane composition. Pharmacologic G9a inhibition promoted Treg expansion in vivo upon antigen (gliadin) stimulation and ameliorated acute trinitrobenzene sulfonic acid-induced colitis secondary to tissue-specific Treg development. Finally, Tregs lacking G9a expression (G9a-knockout Tregs) remain functional chronically and can rescue T-cell transfer-induced colitis. CONCLUSION: G9a inhibition promotes cholesterol metabolism in T cells, favoring a metabolic profile that facilitates Treg development in vitro and in vivo. Our data support the potential use of G9a inhibitors in the treatment of immune-mediated conditions including inflammatory bowel disease.

Imaging Evaluation of Inflammatory Bowel Disease Complications.

Inflammatory bowel disease (IBD) is a chronic inflammatory condition that can progress to fibrostenotic and penetrating complications. Cross-sectional imaging is often needed for accurate diagnosis of IBD complication and for planning the appropriate management strategy. Computed tomography enterography, magnetic resonance enterography, and IBD ultrasound have become key tools for clinicians and interventional endoscopists. This article highlights and discusses various radiologic imaging techniques and their application to the diagnosis and management of IBD complications.

The Impact of Alcohol in Inflammatory Bowel Diseases.

Several environmental factors have been implicated in the pathogenesis of inflammatory bowel diseases (IBD); however, the evidence for alcohol is sparse, as is its implications on disease activity and overall management. Here, we examine the available evidence for the effect of alcohol on IBD, including its association with the development of IBD, role in exacerbations, and potential medication interactions. Several mechanisms have been demonstrated to mediate the effects of ethanol in the gastrointestinal tract. Alcohol has been shown to alter the gut microbiome, disrupt intestinal barrier, and increase intestinal permeability, directly and indirectly promoting immune activation. Conversely, specific alcoholic beverages, notably red wine, may have anti-inflammatory properties capable of assisting in disease control and affecting disease monitoring. Nonetheless, most alcohol-mediated effects seem to facilitate intestinal inflammation and consequently impact disease onset, recurrence, and symptom control. Furthermore, alcohol use interferes with the metabolism of several medications leading to increased side effect profiles or even loss of effect. Notably, mesalamine, azathioprine, methotrexate, and biologic medications can all be affected by concomitant alcohol intake via a variety of mechanisms.

Cryptogenic multifocal ulcerous stenosing enteritis (CMUSE): a 20-year single-center clinical and radiologic experience.

OBJECTIVE: The purpose of this article is to describe clinical and imaging characteristics of confirmed cases of cryptogenic multifocal ulcerous stenosing enteritis (CMUSE). METHODS: Retrospective review of electronic medical records identified patients considered for a diagnosis CMUSE over 20-years in a single large tertiary center. Clinical data were abstracted and diagnosis was confirmed based on published criteria. Two GI radiologists reviewed CT and MR enterography (CTE/MRE) exams in consensus of confirmed patients to characterize the imaging features of CMUSE. RESULTS: Eight patients with confirmed CMUSE diagnosis were included for image review, and 9 CTEs and 1 MRE were analyzed. Most patients were males (75%) with a median age at diagnosis of 59.5 years (25-71) presenting with iron deficiency anemia (75%). Patients were commonly refractory (87.5%) to their first therapy, including steroids, with half being refractory to surgical intervention. Major imaging features included multiple (≥ 5; 88%; 7/8), short (< 2 cm; 100%; 8/8), circumferential (100%; 8/8) strictures with moderate wall thickening (6-9 cm), and stratified hyper enhancement (100%; 8/8) located in the ileum (100%; 8/8). Median proximal small bowel dilation was 2.95 cm (2.5-4.1 cm). No CMUSE cases demonstrated penetrating disease (e.g., abscess, fistula). CONCLUSION: CT and MR enterography are invaluable tools in the multidisciplinary diagnostic evaluation of CMUSE, a rare cause of small bowel strictures with overlapping clinical and imaging features of Crohn's disease and NSAID enteropathy.

Certolizumab Trough Levels and Antibodies in Crohn Disease: A Single-Center Experience.

Background: Certolizumab pegol (CZP) has been successfully used for the treatment of Crohn disease (CD); however, real-world data regarding the utility of CZP trough levels (CTLs) are lacking. We aimed to correlate CTL with CD outcomes and to determine frequency of CZP antibodies. Methods: Retrospective evaluation of all CD patients on maintenance CZP with CTL obtained between 2016 and 2019. Outcomes included: median CTL, presence of anti-CZP antibodies, biochemical response (BR), clinical response (CR), radiologic response (RR), radiologic healing (RH), and mucosal healing (MH). Results: Seventy-seven CD patients were included. Median CTL was 18.9 µg/mL (interquartile range, 7.6-35.4). Twenty-three patients (27.3%) had positive antibody levels, with lower median CTL compared to patients with no antibodies (0.0 vs 29.8; P < 0.0001). Median CTL levels were higher in patients with vs without CR (30.4 vs 10.3 µg/mL; P = 0.0015) and RR (29.6 vs 5.8 µg/mL; P = 0.006). CZP dosing at least every 2 weeks was associated with higher odds of achieving MH (odds ratio, 3.2; 95% confidence interval, 1.03-9.97). CTL resulted in change in clinical management in 62.7% of cases and presence of CMZ antibodies was associated with an odds ratio of 5.83 (95% confidence interval, 1.57-21.73) of change in management. Receiver operating characteristic curve and quartile analysis suggested that CTL >19 µg/mL is associated with increased rates of CR and RR. Conclusions: Higher CTL was significantly associated with CR and RR. The rate of CZP antibodies was 27.3%. Our data suggest maintenance CTL of ≥19 µg/mL should be achieved in order to optimize outcomes in clinical practice.

The Impact of Vedolizumab on Pre-Existing Extraintestinal Manifestations of Inflammatory Bowel Disease: A Multicenter Study.

BACKGROUND: There are limited data on how vedolizumab (VDZ) impacts extraintestinal manifestations (EIMs) in inflammatory bowel disease (IBD). The aim of this study was to determine the clinical outcomes of EIMs after initiation of VDZ for patients with IBD. METHODS: A multicenter retrospective study of patients with IBD who received at least 1 dose of VDZ between January 1, 2014 and August 1, 2019 was conducted. The primary outcome was the rate of worsening EIMs after VDZ. Secondary outcomes were factors associated with worsening EIMs and peripheral arthritis (PA) specifically after VDZ. RESULTS: A total of 201 patients with IBD (72.6% with Crohn disease; median age 38.4 years (interquartile range, 29-52.4 years); 62.2% female) with EIMs before VDZ treatment were included. The most common type of EIM before VDZ was peripheral arthritis (PA) (68.2%). Worsening of EIMs after VDZ occurred in 34.8% of patients. There were no statistically significant differences between the worsened EIM (n = 70) and the stable EIM (n = 131) groups in term of age, IBD subtype, or previous and current medical therapy. We found that PA was significantly more common in the worsening EIM group (84.3% vs 59.6%; P < 0.01). Worsening of EIMs was associated with a higher rate of discontinuation of VDZ during study follow-up when compared with the stable EIM group (61.4% vs 44%; P = 0.02). Treatment using VDZ was discontinued specifically because of EIMs in 9.5% of patients. CONCLUSIONS: Almost one-third of patients had worsening EIMs after VDZ, which resulted in VDZ discontinuation in approximately 10% of patients. Previous biologic use or concurrent immunosuppressant or corticosteroid therapy did not predict EIM course after VDZ.

SMAD4 mutation and the combined juvenile polyposis and hereditary hemorrhage telangiectasia syndrome: a single center experience.

PURPOSE: Mutations of the SMAD4 gene can result in a distinct syndrome with combined clinical features of both juvenile polyposis syndrome (JPS) and hereditary hemorrhagic telangiectasia (HHT). Even though it is known that patients with the overlap syndrome are at increased risk for colorectal malignancies and bleeding, the outcomes of this patient population have not been extensively studied. METHODS: Retrospective study aiming to describe the phenotype and clinical outcomes of patients with genetically confirmed JP-HHT combined syndrome in a single large tertiary center in North America. RESULTS: A total of 22 patients were identified, the majority females (59%) with a median age diagnosis at 24 years. Polyps were more commonly seen in the lower gastrointestinal (GI) tract, and tubular adenomas were seen in 50%. Epistaxis and pulmonary arteriovenous malformations (AVM) were the most common manifestations of HHT, with a median Curacao score of 3 [1-4]. Hospitalization for gastrointestinal bleeding and cerebrovascular events occurred at a rate of 28% and 4%, respectively. Two patients had GI malignancies, one rectal and one small bowel adenocarcinoma. Overall mortality was 14%. CONCLUSIONS: Patients with the combined JP-HHT syndrome remain at risk for life-threatening vascular complications and gastrointestinal malignancies; close follow-up is necessary to minimize morbidity and mortality in this patient population.

Patient participation in medical student teaching: a survey of hospital patients.

BACKGROUND: Despite the common practice of involving in-patients in the teaching of medical students little is known about the experience for patients. This study investigated inpatients' willingness, motivations and experience with participation in medical student bedside teaching. METHODS: In-patients at a tertiary hospital who participated in medical student teaching answered a 22 question survey. The survey examined the motivations, impact and overall experience for these patients. RESULTS: During July and August of 2019, 111 patients aged 19-93 years completed the survey. Most patients who were approached by preceptors to participate in teaching agreed to participate (74%). Ninety-six percent of patients felt like they could have said no if they had not wanted to participate in medical student teaching. Ninety percent of patients valued the time they spent with students. CONCLUSIONS: Most hospital inpatients are willing to participate in medical student teaching in order to be helpful, and most have a positive experience. Preceptors in undergraduate medical education should prioritize a quality informed consent process and understand that the teaching experience can be mutually productive for patients and students.

Deregulation of Long Intergenic Non-coding RNAs in CD4+ T Cells of Lamina Propria in Crohn's Disease Through Transcriptome Profiling.

BACKGROUND: The aetiology of Crohn's disease [CD] involves immune dysregulation in a genetically susceptible individual. Genome-wide association studies [GWAS] have identified 200 loci associated with CD, ulcerative colitis, or both, most of which fall within non-coding DNA regions. Long non-coding RNAs [lncRNAs] regulate gene expression by diverse mechanisms and have been associated with disease activity in inflammatory bowel disease. However, disease-associated lncRNAs have not been characterised in pathogenic immune cell populations. METHODS: Terminal ileal samples were obtained from 22 CD patients and 13 controls. RNA from lamina propria CD4+ T cells was sequenced and long intergenic non-coding RNAs [lincRNAs] were detected. Overall expression patterns, differential expression [DE], and pathway and gene enrichment analyses were performed. Knockdown of novel lincRNAs XLOC_000261 and XLOC_000014 was performed. Expression of Th1 or Th17-associated transcription factors, T-bet and RORγt, respectively, was assessed by flow cytometry. RESULTS: A total of 6402 lincRNAs were expressed, 960 of which were novel. Unsupervised clustering and principal component analysis showed that the lincRNA expression discriminated patients from controls. A total of 1792 lincRNAs were DE, and 295 [79 novel; 216 known] mapped to 267 of 5727 DE protein-coding genes. The novel lincRNAs were enriched in inflammatory and Notch signalling pathways [p <0.05]. Furthermore, DE lincRNAs in CD patients were more frequently found in DNA regions with known inflammatory bowel disease [IBD]-associated loci. The novel lincRNA XLOC_000261 negatively regulated RORγt expression in Th17 cells. CONCLUSIONS: We describe a novel set of DE lincRNAs in CD-associated CD4+ cells and demonstrate that novel lincRNA XLOC_000261 appears to negatively regulate RORγt protein expression in Th17 cells.

Mechanisms of Disease: Inflammatory Bowel Diseases.

Inflammatory bowel diseases (IBDs), represented by Crohn disease and ulcerative colitis, are associated with major morbidity in Western countries and with increasing incidence in the developing world. Although analysis of the genome of patients with IBD, especially through genome-wide association studies, has unraveled multiple pathways involved in IBD pathogenesis, only part of IBD heritability has been explained by genetic studies. This finding has revealed that environmental factors also play a major role in promoting intestinal inflammation, mostly through their effects in the composition of the microbiome. However, in order for microbial dysbiosis to result in uncontrolled intestinal inflammation, the intestinal barrier formed by intestinal epithelial cells and the innate immune system should also be compromised. Finally, activation of the immune system depends on the working balance between effector and regulatory cells present in the intestinal mucosa, which have also been found to be dysregulated in this patient population. Therefore, IBD pathogenesis is a result of the interplay of genetic susceptibility and environmental impact on the microbiome that through a weakened intestinal barrier will lead to inappropriate intestinal immune activation. In this article, we will review the mechanisms proposed to cause IBD from the genetic, environmental, intestinal barrier, and immunologic perspectives.

Vedolizumab Drug Level Correlation With Clinical Remission, Biomarker Normalization, and Mucosal Healing in Inflammatory Bowel Disease.

BACKGROUND/AIMS: The clinical utility of vedolizumab (VDZ) trough levels (VTLs) in inflammatory bowel disease (IBD) is not well defined. The aims of this study are to determine the median VTLs and frequency of detected antibodies, the correlation of VTLs with C-reactive protein (CRP) and mucosal healing (MH), and the change in clinical management based on VTLs. METHODS: A cross-sectional study of IBD patients treated with VDZ with VTLs checked between July 1, 2016, and March 1, 2017, was conducted. Mucosal healing was defined as absence of mucosal ulcers in Crohn's disease (CD) and Mayo endoscopic score ≤1 for ulcerative colitis (UC). Normal CRP was defined as ≤8 mg/L. RESULTS: A total of 171 patients (62% CD, 31% UC, 7% indeterminate colitis) were included. Median VTLs was 15.3 ug/mL (range, 0-60), and 1 patient had detectable antibodies to VDZ. Patients with a normal CRP had a median VTLs of 17.3 ug/mL vs 10.7 ug/mL in high CRP patients (P = 0.046). This was noted in CD (20.3 vs 10.4 ug/mL; P = 0.005) but not in UC patients (14.4 vs 20.8; P = 0.72). Mucosal healing was achieved in 35% of patients (37 of 105); among these, median VTLs was 13.7 ug/mL vs 16.1 ug/mL in patients who did not achieve MH (P = 0.64). Vedolizumab trough levels resulted in a change in clinical management in 73%. CONCLUSIONS: Our cohort showed a low rate of immunogenicity to VDZ and an association between VTLs and CRP in CD but not in UC patients. No relationship between VTLs and MH was detected. Vedolizumab trough level measurements altered management in approximately three fourths of patients.

Role of Diagnostic Preoperative Upper Gastrointestinal Endoscopy in Radiologically Confirmed Gastric Volvulus.

BACKGROUND AND AIMS: Gastric volvulus (GV) is a life-threatening condition that warrants prompt diagnosis and treatment. GV is a radiologic diagnosis. The role of preoperative upper gastrointestinal endoscopy (UGIE) for individuals with radiologically confirmed GV is poorly defined. Our objective was to assess the diagnostic yield of UGIE in the preoperative evaluation of patients presenting with radiologically confirmed GV. METHODS: Retrospective review of all adult patients undergoing surgery for GV between July 1996 and August 2016 has been carried out. We performed analyses evaluating diagnostic yield of preoperative UGIE and compared outcomes in patients who did and did not undergo preoperative UGIE. Outcomes were diagnostic yield of preoperative UGIE, length of hospital stay, postoperative complications, and mortality at 30 days and 1 year. RESULTS: In the preoperative UGIE group, the diagnostic yield was 34.6% (27/78). The most common endoscopic findings were erosive esophagitis (13/27) and clean based gastric or duodenal ulcers (5/27). There were no cases of esophago-gastric malignancy. Three patients had ulcers with stigmata of recent bleeding, and three patients had features suggestive of gastric ischemia. Endoscopic findings did not influence surgical management. There was no statistically significant difference in mortality between patients who did and did not undergo preoperative UGIE, both at 30 days (0 vs. 2.5%) and 1 year (3.8 vs. 7.5%). CONCLUSION: Among patients with radiologically confirmed GV, preoperative UGIE rarely demonstrates clinically significant findings and can potentially delay definitive surgical intervention.

Isolated hepatic non-obstructive sinusoidal dilatation, 20-year single center experience.

AIM: To characterize isolated non-obstructive sinusoidal dilatation (SD) by identifying associated conditions, laboratory findings, and histological patterns. METHODS: Retrospectively reviewed 491 patients with SD between 1995 and 2015. Patients with obstruction at the level of the small/large hepatic veins, portal veins, or right-sided heart failure were excluded along with history of cirrhosis, hepatic malignancy, liver transplant, or absence of electrocardiogram/cardiac echocardiogram. Liver histology was reviewed for extent of SD, fibrosis, red blood cell extravasation, nodular regenerative hyperplasia, hepatic peliosis, and hepatocellular plate atrophy (HPA). RESULTS: We identified 88 patients with non-obstructive SD. Inflammatory conditions (32%) were the most common cause. The most common pattern of liver abnormalities was cholestatic (76%). Majority (78%) had localized SD to Zone III. Medication-related SD had higher proportion of portal hypertension (53%), ascites (58%), and median AST (113 U/L) and ALT (90 U/L) levels. Nineteen patients in our study died within one-year after diagnosis of SD, majority from complications related to underlying diseases. CONCLUSION: Significant proportion of SD and HPA exist without impaired hepatic venous outflow. Isolated SD on liver biopsy, in the absence of congestive hepatopathy, requires further evaluation and portal hypertension should be rule out.

Outcomes of endoscopic intervention for overt GI bleeding in severe thrombocytopenia.

BACKGROUND AND AIMS: Gastrointestinal bleeding (GIB) in the setting of thrombocytopenia raises concerns about endoscopic procedure risk. We aimed to assess the safety and outcomes of endoscopy for overt GIB in the setting of severe thrombocytopenia in liver cirrhosis (LC) and non-liver cirrhosis (NLC). METHODS: This is a retrospective study on inpatients who underwent endoscopy within 24 hours of presentation for overt GIB with a platelet count (PC) of 20 to <50 × 103/mL. Outcomes included diagnostic and therapeutic yields, procedural adverse events, packed red blood cell (pRBC) and platelet transfusions, recurrent bleeding rate, and all-cause and GIB-related mortality. RESULTS: One hundred forty-four patients were identified. The median PC was 41 × 103/mL and 61% had LC. The diagnostic yield was 68% (LC = 61%, NLC = 79%, P = .04). Therapeutic yield was 60% (59% vs 60%, P = 1.00). The initial hemostasis rate was 94% with one adverse event. The median number of pRBC and platelet transfusions decreased after intervention in the entire cohort. Recurrent bleeding rates were 22% at 1 month and 30% at 1 year, with no differences between groups. An increased international normalized ratio (INR) >2 was a predictor of recurrent bleeding. All-cause mortality was 19% at 1 month and 37% at 1 year, whereas GIB-associated mortality in our cohort was only 3% at 1 month and 4% at 1 year, with no significant difference between LC and NLC. Predictors of mortality were INR >2, activated partial thromboplastin time >38 seconds, hypotension, intensive care unit admission, and pulmonary comorbidities. CONCLUSION: In this study cohort, we observed that endoscopy for overt GIB in the setting of severe thrombocytopenia in patients with LC and NLC appears safe, has moderate diagnostic and therapeutic yields with high initial hemostasis rate, and is associated with a significant decrease in pRBC and platelet transfusions. Recurrent bleeding and all-cause mortality rates remain high.

The Role of Histone Methyltransferases and Long Non-coding RNAs in the Regulation of T Cell Fate Decisions.

T cell lineage decisions are critical for the development of proper immune responses to pathogens as well as important for the resolution of inflammatory responses. This differentiation process relies on a combination of intrinsic and extrinsic factors converging upon epigenetic regulation of transcriptional networks relevant to specific T cell lineages. As these biochemical modifications represent therapeutic opportunities in cancer biology and autoimmunity, implications of writers and readers of epigenetic marks to immune cell differentiation and function are highly relevant. Given the ready adoption of histone methyltransferase inhibitors in the clinic, we focus this review on the role of three histone modifying complexes: PRC-1, PRC-2, and G9A in modulating T cell fate decisions. Furthermore, we explore the role of long non-coding RNAs in regulating these processes, and discuss recent advances and challenges of implementing epigenetic therapies into clinical practice.

Targeting Specific Immunologic Pathways in Crohn's Disease.

Understanding the immunologic pathways in intestinal inflammation is crucial for the development of new therapies that can maximize patient response and minimize toxicity. Targeting integrins and cytokines is intended to control leukocyte migration to effector sites or inhibit the action of proinflammatory cytokines. New approaches to preventing leukocyte migration may target integrin receptors expressed on the intestinal vascular endothelium. The interleukin (IL)-12/IL-23 pathway has been a therapeutic target of interest in controlling active Crohn's disease (CD). New therapeutic approaches in CD may involve the enhancement of anti-inflammatory cytokine pathways and modulation of cellular responses and intranuclear signals associated with intestinal inflammation.