Interleukin 21 Drives a Hypermetabolic State and CD4+ T-Cell-Associated Pathogenicity in Chronic Intestinal Inflammation

BACKGROUND & AIMS

Incapacitated regulatory T cells (Tregs) contribute to immune-mediated diseases. Inflammatory Tregs are evident during human inflammatory bowel disease; however, mechanisms driving the development of these cells and their function are not well understood. Therefore, we investigated the role of cellular metabolism in Tregs relevant to gut homeostasis.

METHODS

Using human Tregs, we performed mitochondrial ultrastructural studies via electron microscopy and confocal imaging, biochemical and protein analyses using proximity ligation assay, immunoblotting, mass cytometry and fluorescence-activated cell sorting, metabolomics, gene expression analysis, and real-time metabolic profiling utilizing the Seahorse XF analyzer. We used a Crohn's disease single-cell RNA sequencing dataset to infer the therapeutic relevance of targeting metabolic pathways in inflammatory Tregs. We examined the superior functionality of genetically modified Tregs in CD4+ T-cell-induced murine colitis models.

RESULTS

Mitochondria-endoplasmic reticulum appositions, known to mediate pyruvate entry into mitochondria via voltage-dependent anion channel 1 (VDAC1), are abundant in Tregs. VDAC1 inhibition perturbed pyruvate metabolism, eliciting sensitization to other inflammatory signals reversible by membrane-permeable methyl pyruvate supplementation. Notably, interleukin (IL) 21 diminished mitochondria-endoplasmic reticulum appositions, resulting in enhanced enzymatic function of glycogen synthase kinase 3 β, a putative negative regulator of VDAC1, and a hypermetabolic state that amplified Treg inflammatory response. Methyl pyruvate and glycogen synthase kinase 3 β pharmacologic inhibitor (LY2090314) reversed IL21-induced metabolic rewiring and inflammatory state. Moreover, IL21-induced metabolic genes in Tregs in vitro were enriched in human Crohn's disease intestinal Tregs. Adoptively transferred Il21r-/- Tregs efficiently rescued murine colitis in contrast to wild-type Tregs.

CONCLUSIONS

IL21 triggers metabolic dysfunction associated with Treg inflammatory response. Inhibiting IL21-induced metabolism in Tregs may mitigate CD4+ T-cell-driven chronic intestinal inflammation.

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.

Treg donation of sIL-6R to promote intestinal integrity and repair

IBD affects roughly 1.6 million US adults, with its prevalence increasing since the late 1990s. Characterized by unchecked intestinal inflammation, multiple proinflammatory cytokines including IL6 have been implicated as critical factors in this pathology. It has been established that EZH2 is a gene involved in the production of specific histone methyltransferase enzymes, as well as in the differentiation of Treg cells. The association between the Treg master transcription factor, Foxp3 and EZH2 results in the suppressive function of Tregs, with our previous work revealing impairment of this interaction under the influence of IL6 signaling in an inflamed intestinal setting. We investigated this further in a murine preventative T cell transfer model of colitis that involved injecting donor Treg cells that lacked IL6Ra, into immunocompromised mice. Histological scoring of the mice receiving the IL6Rko Tregs revealed a resolved inflammatory milieu and flow cytometric analysis of cells isolated from the spleens and MLNs showed increased Foxp3+ expression when compared to mice that received WT Tregs. Foxp3IL6Rako mice were subjected to a DSS model of colitis to further characterize the absence of the IL6R on Treg function in the intestinal milieu. Exacerbated signs of colitis were observed through histology and colon shortening of the conditional knockout mice when compared to their WT counterparts. We postulate that Tregs could be acting as a donor of sILR to promote intestinal integrity and healing. Further experiments will be conducted to define a role for the IL6R in the development of Foxp3+ cells, along with outlining the instrumental process of sIL6R donation in the intestinal milieu.

Supported by Mayo Clinic Graduate School for Biomedical Sciences

Metabolic Dysfunction Governs Regulatory T Cell Inflammatory Response during Inflammatory Bowel Disease

Background

Significant proportion of inflammatory bowel disease (IBD) patients respond inconsistently to therapies, underscoring disease complexity. Interleukin 21 (IL21) is highly expressed during IBD. In addition to T helper (Th) cells, inflammatory regulatory T cells (Tregs) have been linked to refractory IBD. Thus, we explored the metabolic role of IL21 in inducing Treg dysfunction and IBD.

Methods

Human Tregs and Th cells were subjected to transcriptional profiling and metabolic phenotyping. Colitis was induced in Rag1−/− mice by naïve CD4 T cell adoptive transfer.

Results

IL21 stimulation of human Tregs induced glycolysis and OXPHOS. In agreement, IL21 enhanced the expression of genes associated with glycolysis, anabolism, and OXPHOS, leading to inflammatory cytokine production. Mechanistically, we found disruption to mitochondrial integrity with concomitant activation of glycogen synthase kinase 3 (GSK3) β, a kinase known to prevent mitochondrial pyruvate metabolism. IL21-induced GSK3β activation was accompanied by pyruvate and lactate buildup. Notably, GSK3 inhibition or supplementation with membrane-permeable methyl pyruvate abrogated metabolic wiring of and inflammatory responses by IL21-stimulated Tregs and effector Th cells. These results suggest that impaired mitochondrial pyruvate metabolism is a feature of inflammatory CD4 T cells. Lastly, GSK3 inhibition prevented pathogenic CD4 T cell-induced colitis in mice, as evidenced by reduced Mouse Colon Histology Index and serum inflammatory cytokines.

Conclusions

IL21 engages Tregs in a hypermetabolic state that augments inflammatory cytokine production. Therefore, desensitizing CD4 T cells to IL21 may also augment Treg function during IBD.

Supported by NIDDK award K01DK124358, the Center for Cell Signaling in Gastroenterology (P30DK084567), and the Mayo Clinic Center for Biomedical Discovery.

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.

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.

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.

Alcohol Use in Patients With Inflammatory Bowel Disease

Alcohol consumption is common in patients with inflammatory bowel disease (IBD), but alcohol has been reported to be the most-avoided diet item by this patient population. This article explores the available evidence for the impact that alcohol use has on IBD development, relapse, symptom control, and medication interactions. Although evidence linking the consumption of alcoholic beverages and the development of new-onset IBD is controversial, prospective research has reported that alcohol use is associated with a higher risk of relapse. Moreover, patients with IBD report worse gastrointestinal symptoms following alcohol consumption. On the other hand, alcoholic beverages such as red wine may have anti-inflammatory properties capable of assisting in disease control, although they may also have a negative effect on disease monitoring, namely fecal calprotectin levels. Importantly, the use of alcohol can interfere with the metabolism of several medications, leading to increased adverse events or even loss of efficacy. In the available literature, alcohol use in patients with IBD trends toward harmful effects; however, more research is needed to provide confident recommendations.

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.

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.

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.

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.

Rituximab Maintenance Therapy Reduces Rate of Relapse of Pancreaticobiliary Immunoglobulin G4-related Disease

BACKGROUND & AIMS

IgG4-related disease (IgG4-RD), a multi-organ fibroinflammatory syndrome, typically responds to steroids. However, some cases are steroid resistant, and pancreaticobiliary IgG4-RD commonly relapses after steroid withdrawal. Rituximab induces remission of IgG4-RD, but the need for and safety of maintenance rituximab treatment are unknown. We compared outcomes of patients with pancreaticobiliary IgG4-RD treated with or without maintenance rituximab therapy.

METHODS

We performed a retrospective study of patients with pancreaticobiliary IgG4-RD treated with rituximab at the Mayo Clinic in Rochester, Minnesota, from January 2005 through December 2015. The cohort was divided into patients who received only rituximab induction therapy (group 1, n = 14) and patients who received rituximab induction followed by maintenance therapy (group 2, n = 29). We collected data on recurrence of IgG4-RD symptoms and findings, as well as information on evaluations, treatment, and adverse events.

RESULTS

Median follow-up times were similar between group 1 (34 mo) and group 2 (27 mo) (P = .99). Thirty-seven patients (86%) were in steroid-free remission 6 months after rituximab initiation. A higher proportion of patients in group 1 had disease relapse (3-year event rate, 45%) than in group 2 (3-year event rate, 11%) (P = .034). Younger age, higher IgG4 responder index score after induction therapy, and increased serum levels of alkaline phosphatase at baseline or after rituximab induction were associated with relapse. Infections developed in 6 of 43 patients, all in group 2 (P = .067 vs group 1); all but 1 occurred during maintenance therapy.

CONCLUSIONS

In a retrospective study of patients with pancreaticobiliary IgG4-RD, we found rituximab maintenance therapy prolongs remission. Relapses are uncommon among patients receiving maintenance therapy, but maintenance therapy may increase risk of infection. Patients with factors that predict relapse could be candidates for rituximab maintenance therapy.

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.

Outcomes of repeat balloon assisted enteroscopy in small-bowel bleeding

BACKGROUND/AIMS

 The rate of recurrent small-bowel bleeding (SBB) remains high despite the advent of balloon assisted enteroscopy (BAE). The study aims were to determine: (1) the diagnostic and therapeutic yields, and adverse event rate of repeat BAE in SBB, and (2) the predictors of a positive repeat BAE.

METHODS

 A retrospective review of a BAE database was conducted. Patients who had > 1 BAE for SBB were included. Primary outcomes were diagnostic yield, therapeutic yield, and adverse events of repeat BAE. Secondary outcomes were predictors of a positive repeat BAE.

RESULTS

 A total of 175 patients (55 % men; mean age 64.1 ± 16.3 years) were included. The diagnostic and therapeutic yields of repeat BAE were 55 % and 42 %, respectively. Repeat BAE adverse events occurred in 5 % with self-limited abdominal pain being most common. Patients with a positive repeat BAE were significantly older than the negative group (68.6 ± 13.9 vs. 60.9 ± 17.1; P  = 0.001) and were more likely to have cardiac comorbidities (OR 2.4, 95 %CI: 1.3 - 4.6; P  = 0.01), chronic kidney disease (OR 2.3, 95 %CI: 1.1 - 4.9; P  = 0.04), chronic obstructive pulmonary disease (OR 3.3, 95 %CI: 1.3 - 8.1; P  = 0.01), positive initial BAE (OR 3.6, 95 %CI: 1.9 - 6.8; P  < 0.001), and antegrade procedure (OR 3.3, 95 %CI: 1.7 - 6.1; P  < 0.001). On multivariate analysis, a positive initial BAE and antegrade route were the only significant predictive factors.

CONCLUSIONS

 Performing a repeat BAE for SBB appears safe and provided modest yields. A positive initial BAE and antegrade route were predictive of a positive repeat BAE.

Gastrointestinal Bleeding Secondary to Iliac Artery Pseudoaneurysm in a Patient With Remote Pancreas Transplant: A Case Report

BACKGROUND

Vascular complications represent the most common cause of early graft failure after pancreatic transplantation (PT). Pseudoaneurysms are uncommon vascular complications that usually present within the first year post transplantation.

CASE REPORT

A 49-year-old man with history of type 1 diabetes mellitus presented for evaluation with a 2-day history of painless hematochezia. He had undergone PT 4 years prior to presentation, which failed due to acute cellular rejection after 1 year. Both extended upper endoscopy and colonoscopy did not identify an active bleeding source. After an episode of massive hematochezia, he became hemodynamically unstable with peritoneal signs noted on physical examination. An abdominal angiogram was unable to identify active hemorrhage, and the patient was transferred to the operating room for open laparotomy. Exploration revealed a right common iliac artery pseudoaneurysm eroding into the pancreatic-ileal anastomosis, which required initial digital compression for initial hemostasis. After combined endovascular procedure with ballooning and stenting of the right iliac artery, optimal hemostasis was achieved without further episodes of hematochezia.

DISCUSSION

Gastrointestinal bleeding (GIB) has been reported to occur in 11% of enteric-drained PT. Even though infectious causes have been reported, culprits are more commonly associated with vascular or enteric surgical anastomosis and usually occur within the early postoperative course. Here we report an uncommon cause of GIB, a late complication of PT, and review important points associated with the management of GIB, anatomy of PT, and potential etiologies for early and late GIB in the setting of PT.

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.

Spontaneous intramural small bowel hematoma in a patient with acute myeloid leukaemia receiving chemotherapy and nilotinib

Spontaneous intramural small bowel hematoma (SISBH) is a rare, acute abdominal condition, with increasing incidence in recent years. Excessive anticoagulation with vitamin K antagonists is the most common aetiology. We report the case of a large acute jejunal intramural hematoma in a patient with newly diagnosed acute myeloid leukaemia receiving chemotherapy and nilotinib. The patient presented with abdominal pain, haematochezia, acute anaemia and thrombocytopenia. CT of the abdomen and pelvis revealed SISBH. The patient was managed conservatively with supportive management and cessation of nilotinib therapy. The patient's symptoms improved, with subsequent CT imaging confirming resolution. This case highlights an uncommon cause of gastrointestinal bleed usually diagnosed only after radiological imaging. A correct diagnosis is important as SISBH usually responds to conservative measures, and may obviate the patient from unnecessary invasive investigations.

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.

Targeted Approaches Applied to Uncommon Diseases: A Case of Salivary Duct Carcinoma Metastatic to the Brain Treated with the Multikinase Inhibitor Neratinib

Salivary duct carcinoma is a rare malignancy associated with hormone receptor and human epidermal growth factor receptor 2 (HER2) overexpression. Local surgical control is the cornerstone of therapy, but a subset of patients develops metastatic disease portending a poor prognosis and limited management options. Intracranial metastases are an uncommon manifestation and present a therapeutic challenge. We report the case of a 31-year-old male who presented with facial pain and swelling subsequently diagnosed with salivary duct carcinoma. Our patient underwent extensive locoregional resection and analysis of the tumor tissue demonstrated evidence of androgen receptor expression and HER2 overexpression. His course was complicated by metastatic extra- and intracranial recurrence despite combined modality treatment with radiation and chemotherapy followed by anti-HER2 monoclonal antibody therapy and androgen deprivation therapy. After exhausting standard treatment options, he received experimental therapy with a new small-molecule tyrosine kinase inhibitor, neratinib, with evidence of a transient clinical response and no significant adverse effects. This case exemplifies the potential and limitations of targeted therapy, particularly when applied to patients with rare diseases and presentations.

Initial presentation of CNS-restricted acute lymphoblastic B cell leukaemia as peripheral polyneuropathy

We report a case of a 58-year-old woman who presented with a 1-month course of progressive lower and upper extremity weakness in addition to binocular diplopia. Diagnostic lumbar puncture revealed atypical lymphoid cells with 28% blasts. Immunophenotype was consistent with B cell acute lymphoblastic leukaemia (B-ALL). Further work up showed no systemic involvement but extensive thoracolumbar-sacral leptomeningeal disease. The patient was treated with several courses of intrathecal and systemic chemotherapy followed by craniospinal irradiation for consolidation. There was initial steady improvement in neurological symptoms and leptomeningeal disease, the latter being ascertained through radiological studies and cerebrospinal fluid examination. After 10 months of response, the patient relapsed with central nervous system (CNS) and systemic disease. B-ALL is a rare precursor lymphoid neoplasm that generally presents with systemic disease. While CNS involvement is not uncommon, isolated involvement of this compartment without systemic disease is exceedingly rare.

The temperature of water ingested ad libitum does not influence performance during a 40-km self-paced cycling trial in the heat

AIM

The aim of the present study was to evaluate the effects of the temperature of ingested water on performance during a 40-km self-paced cycling trial in the heat (35º C and 60% relative humidity).

METHODS

The study was randomized, counterbalanced, crossover and single-blinded. Ten well-trained male cycling athletes (cyclists, mountain bikers or triathletes) who were non-acclimatized to heat were subjected to four experimental situations divided into two sets. In the first set, the participants performed two trials, during which they were given either cold (10º C) or warm water (37º C) ad libitum. In these situations, the volume and timing of the water ingestion (when each bolus was ingested) were recorded and replicated in the second set, but the water temperature was reversed.

RESULTS

The performance times were unaffected by the water intake volume (P=0.425), but the water at a temperature of 37º C tended to induce lower performance times (P=0.078) during the trials (AL10=93.0±3.5 min; AL37=94.4±4.1 min; SC10=93.4±4.0; SC37=97.4±4.3 min). The water intake was greater when the water was cold (P<0.05), but the temperature did not affect the heat storage rate, rectal temperature, mean skin temperature, heart rate, blood glucose level, sweat loss, sweat rate, perceived exertion rate or plasma volume changes. However, a significant reduction in the plasma volume change from pre- to postexercise was observed (P<0.01).

CONCLUSION

The performance, thermoregulatory, cardiovascular and metabolic responses during a 40-km self-paced cycling trial in the heat were unaffected by different water temperatures.