Association of celiac disease with eosinophilic esophagitis: Nationwide register-based cohort study with sibling analyses

Background

Celiac disease (CeD) is associated with several immune-mediated disorders, but it is unclear whether it is associated with eosinophilic esophagitis (EoE).

Objective

We sought to examine the risk of EoE in patients with biopsy-verified CeD compared with matched controls and siblings.

Methods

Using nationwide population-based histopathology data, we identified 27,338 patients with CeD diagnosed in the period 2002 to 2017 in Sweden. Patients with CeD were age- and sex-matched with up to 5 reference individuals (n = 134,987) from the general population. Cox Regression was used to estimate hazard ratios (HRs) for developing biopsy-verified EoE. In a secondary analysis, we used unaffected siblings of patients with CeD as comparators to adjust for intrafamilial confounding.

Results

The median age at CeD diagnosis was 27 years, and 63.3% were female patients. During a median follow-up of 8.1 years, 17 patients with CeD and 13 matched reference individuals were diagnosed with EoE. This corresponded to incidence rates of 0.08 versus 0.01 per 1000 person-years, respectively, and an adjusted HR for EoE of 6.65 (95% CI, 3.26-13.81). Compared with their siblings without CeD, patients with CeD were however at a no increased risk of EoE (HR, 1.39; 95% CI, 0.55-3.51).

Conclusions

In this study, individuals with CeD were at a 6.6-fold increased risk of later EoE compared with the general population. This association might be explained by an altered health-seeking behavior or through shared genetic or early environmental factors because the excess risk disappeared in sibling analyses.

An esophagus cell atlas reveals dynamic rewiring during active eosinophilic esophagitis and remission

Coordinated cell interactions within the esophagus maintain homeostasis, and disruption can lead to eosinophilic esophagitis (EoE), a chronic inflammatory disease with poorly understood pathogenesis. We profile 421,312 individual cells from the esophageal mucosa of 7 healthy and 15 EoE participants, revealing 60 cell subsets and functional alterations in cell states, compositions, and interactions that highlight previously unclear features of EoE. Active disease displays enrichment of ALOX15+ macrophages, PRDM16+ dendritic cells expressing the EoE risk gene ATP10A, and cycling mast cells, with concomitant reduction of TH17 cells. Ligand-receptor expression uncovers eosinophil recruitment programs, increased fibroblast interactions in disease, and IL-9+IL-4+IL-13+ TH2 and endothelial cells as potential mast cell interactors. Resolution of inflammation-associated signatures includes mast and CD4+ TRM cell contraction and cell type-specific downregulation of eosinophil chemoattractant, growth, and survival factors. These cellular alterations in EoE and remission advance our understanding of eosinophilic inflammation and opportunities for therapeutic intervention.

Eosinophilic esophagitis is associated with increased risk of later inflammatory bowel disease in a nationwide Swedish population cohort

BACKGROUND

Earlier studies on the possible association between eosinophilic esophagitis (EoE) and inflammatory bowel disease (IBD) have been contradictory.

METHODS

Patients with biopsy-verified EoE diagnosed between 1990 and 2017 in Sweden (n = 1587) were age- and sex-matched with up to five general population reference individuals (n = 7808). EoE was defined using pathology reports from all 28 pathology centers in Sweden (the ESPRESSO study). Multivariate Cox regression then estimated hazard ratios for future IBD. IBD was defined based on the international classification of disease codes and histopathology codes. In secondary analyses, sibling comparators were used to further reduce potential familial confounding. Additionally, we performed logistic regression examining earlier IBD in EoE.

RESULTS

During follow-up until 2020, 16 (0.01%) EoE patients and 21 (0.003%) general population reference individuals diagnosed with IBD, corresponding to a 3.5-fold increased risk of future IBD (aHR = 3.56; 95% CI 1.79-7.11). EoE was linked to Crohn's disease (aHR = 3.39 [95% CI 1.02-9.60]) but not to ulcerative colitis (aHR = 1.37; 95% CI 0.38-4.86). Compared to their siblings, patients with EoE were at a 2.48-fold increased risk of IBD (aHR = 2.48; 95% CI 0.92-6.70). Earlier IBD was 15 times more likely in EoE patients than in matched reference individuals (odds ratio, 15.39; 95% CI 7.68-33.59).

CONCLUSION

In this nationwide cohort study, EoE was associated with a 3.5-fold increased risk of later IBD diagnosis. This risk increase may be due to shared genetic or early environmental risk factors, but also surveillance bias could play a role.

Pregnancy Outcomes in Females with Eosinophilic Esophagitis: A Nationwide Population-Based Study

Introduction

Eosinophilic esophagitis (EoE) is a chronic, allergic inflammatory disease of the esophagus. It has a peak incidence in the 2nd and 3rd decades of life. Despite this, little is known about pregnancy outcomes in patients with EoE.

Methods

Using a validated histopathologic and nationwide population-based cohort for the diagnosis of EoE, we examined maternal and fetal outcomes, with preterm birth as the primary outcome, in females with EoE compared to matched controls. Odds ratios (ORs) were calculated using logistic regression.

Results

Between 1992 and 2016, we identified 19 females with EoE who gave birth to 23 children (reference births: n = 115). There was 1 (4.3%) preterm birth in the EoE cohort versus 8 (7.0%) in the reference cohort (OR = 0.60; 95% CI = 0.07-5.14). Secondary fetal outcomes included stillbirth, neonatal death, small for gestational age, low birth weight (LBW), and low Apgar score. Of these, LBW (<2,500 g) in patients with EoE compared to controls correlated to an OR of 12.42 (95% CI = 1.26-122.42); however, this finding was based on very low numbers. The remaining fetal outcomes were not significantly different between females with EoE and controls. Secondary pregnancy and maternal outcomes including induction of labor, instrumental delivery, gestational diabetes, or pre-eclampsia were not significantly different between patients with EoE and controls.

Discussion/Conclusion

Overall in this nationwide cohort study, we did not find increased association of preterm birth in patients with EoE.

Prior hospital-based infection and risk of eosinophilic esophagitis in a Swedish nationwide case-control study

BACKGROUND AND AIMS

Eosinophilic esophagitis (EoE) is an increasingly common, largely food allergen-driven disease characterized by dysphagia. Prior infections are known to associate with other loss of tolerance diseases such as autoimmunity. We aimed to determine if antecedent infection was associated with later EoE development.

METHODS

We performed a case-control study of all patients with biopsy-verified EoE diagnosed between 2000 and 2017 in Sweden (n = 1587) and matched to 5 general population controls (n = 7660). Cases were identified using histopathology codes from the Epidemiology Strengthened by histopathology Reports in Sweden study, a validated cohort of gastrointestinal pathology reports from all 28 pathology centers in Sweden. We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals for antecedent infections from patients seen at hospital-based outpatient clinics or inpatients. In secondary analyses, we compared EoE patients with their full siblings to further reduce residual confounding.

RESULTS

564 (35.7%) EoE patients and 1793 (23.4%) matched controls had an earlier record of infection. This corresponded to a 2-fold increased risk of infections in EoE patients (OR 2.01; 95%CI: 1.78-2.27). ORs for earlier gastrointestinal or respiratory infection were 2.73 (n = 128 EoE, 268 control; 95%CI: 2.17-3.41) and 1.89 (n = 305 EoE, 960 control; 95%CI: 1.63-2.20), respectively. Having an EoE diagnosis was linked to a 3.39-fold increased odds of sepsis (n = 14 EoE, 21 control; 95%CI: 1.68-6.65). Individuals with EoE were also more likely to have had an infection compared to their non-EoE siblings (n = 427 EoE, 593 control; OR = 1.57; 95%CI = 1.30-1.89).

CONCLUSION

In this nationwide cohort study, prior infection, was associated with subsequent EoE. Risks were particularly high after sepsis, and gastrointestinal or respiratory infections.

Single-cell profiling of environmental enteropathy reveals signatures of epithelial remodeling and immune activation

Environmental enteropathy (EE) is a subclinical condition of the small intestine that is highly prevalent in low- and middle-income countries. It is thought to be a key contributing factor to childhood malnutrition, growth stunting, and diminished oral vaccine responses. Although EE has been shown to be the by-product of a recurrent enteric infection, its full pathophysiology remains unclear. Here, we mapped the cellular and molecular correlates of EE by performing high-throughput, single-cell RNA-sequencing on 33 small intestinal biopsies from 11 adults with EE in Lusaka, Zambia (eight HIV-negative and three HIV-positive), six adults without EE in Boston, United States, and two adults in Durban, South Africa, which we complemented with published data from three additional individuals from the same clinical site. We analyzed previously defined bulk-transcriptomic signatures of reduced villus height and decreased microbial translocation in EE and showed that these signatures may be driven by an increased abundance of surface mucosal cells-a gastric-like subset previously implicated in epithelial repair in the gastrointestinal tract. In addition, we determined cell subsets whose fractional abundances associate with EE severity, small intestinal region, and HIV infection. Furthermore, by comparing duodenal EE samples with those from three control cohorts, we identified dysregulated WNT and MAPK signaling in the EE epithelium and increased proinflammatory cytokine gene expression in a T cell subset highly expressing a transcriptional signature of tissue-resident memory cells in the EE cohort. Together, our work elucidates epithelial and immune correlates of EE and nominates cellular and molecular targets for intervention.

Models and Tools for Investigating Eosinophilic Esophagitis at the Bench

Eosinophilic esophagitis (EoE) is an increasingly common food allergy disease of the esophagus that received its medical designation code in 2008. Despite this recency, great strides have been made in the understanding of EoE pathophysiology and type 2 immunity through basic and translational scientific investigations conducted at the bench. These advances have been critical to our understanding of disease mechanisms and generating new hypotheses, however, there currently is only one very recently approved FDA-approved therapy for EoE, leaving a great deal to be uncovered for patients with this disease. Here we review some of the innovative methods, models and tools that have contributed to the advances in EoE discovery and suggest future directions of investigation to expand upon this foundation.

Risk of fractures in individuals with eosinophilic esophagitis: nationwide population-based cohort study

BACKGROUND AND AIMS

Eosinophilic esophagitis (EoE) is an emerging, chronic immune-mediated disease for which swallowed topical steroids and proton pump inhibitors (PPIs) represent first-line treatments. Immune-mediated diseases, steroids, and PPI use have been linked to osteoporosis. We assessed the risk of fractures in patients with EoE and determined whether the most commonly used treatments for EoE were associated with increased fracture risk.

METHODS

We followed a nationwide cohort of 1263 individuals in Sweden with biopsy-verified EoE diagnosed between 2005 and 2016 for first-time fracture of any type. Age- and sex-matched reference individuals were retrieved from the Total Population Register (n = 5164). We estimated hazard ratios (HRs) for fracture in relation to EoE diagnosis, steroid exposure, and PPI use. In a separate analysis, we compared fracture risk among individuals with EoE to their siblings (n = 1394).

RESULTS

During 4521 person-years of follow-up, 69 individuals with EoE experienced a first-time fracture (15.3/1000 person-years) compared with 234 reference individuals (12.6/1000 person-years). After adjusting for age, sex, birth year, and county of residence, EoE was not associated with a statistically significantly increased risk of fractures (HR = 1.2, 95% CI = 0.9-1.6). Among EoE individuals, exposure to PPIs and swallowed steroids did not modify the risk of fracture (p for heterogeneity 0.20 and 0.07 respectively). There was no increased risk of fractures in EoE compared to EoE-free siblings.

CONCLUSION

The risk of fracture in EoE was not statistically significantly elevated compared to non-EoE reference individuals. Fracture risk in EoE was not modified by PPIs or steroid use.

Mortality and cancer in eosinophilic gastrointestinal disorders distal to the esophagus: nationwide cohort study 1990-2017

BACKGROUND

Eosinophilic gastrointestinal disorders (EGIDs) include inflammatory conditions with enteric infiltration of eosinophils and resulting symptoms. This study aims to examine a population-based sample of patients for prevalence, mortality, and cancer risk in EGIDs distal to the esophagus.

METHODS

Nationwide, population-based cohort study. EGID was identified through relevant biopsy codes from Sweden's all 28 pathology departments through the ESPRESSO cohort. Individuals with EGID were then matched to general population reference individuals with similar age and sex. Study participants were linked to Swedish healthcare registers. Through Cox regression, we calculated adjusted hazard ratios (aHRs) adjusting for sex, age, county, calendar period, and education.

RESULTS

In total, 2429 patients (56% female) were found to have EGID distal to the esophagus, representing a prevalence of about 1/4800 in the Swedish population. Mean age was 44 years with 11% children at the time of diagnosis. Mortality was increased 17% in patients with EGIDs compared to reference individuals (aHR = 1.17; 95%CI = 1.04-1.33). Excess mortality was seen in gastric and small bowel eosinophilic disease, but not colonic disease (aHR = 1.81; 95%CI = 1.32-2.48, aHR = 1.50; 95%CI = 1.18-1.89, and aHR = 0.99; 95%CI = 0.85-1.16, respectively). Cause specific mortality was driven by cancer-related death (aHR = 1.33; 95%CI = 1.05-1.69). However, this study failed to show an increase in incident cancers (aHR = 1.14; 95%CI = 0.96-1.35). Comparison of EGID individuals with their siblings yielded similar aHRs.

CONCLUSIONS

This study found an increased risk of death in patients with EGIDs distal to the esophagus, with cancer death driving the increase. Proximal gut disease seems to confer the greatest risk. There was no increase in incident cancers.

Alterations in Fecal Microbiomes and Serum Metabolomes of Fatigued Patients With Quiescent Inflammatory Bowel Diseases

BACKGROUND & AIMS

Fatigue is frequent and disabling in patients with inflammatory bowel diseases (IBD) but its mechanisms are poorly understood. We investigated alterations in fecal microbiomes and serum metabolomes and proteomes in patients with quiescent IBD, with vs without fatigue.

METHODS

We performed a prospective observational study of patients (44% women; mean age, 39.8 y) with clinically and endoscopically quiescent Crohn's disease (n = 106) or ulcerative colitis (n = 60) at a tertiary hospital, from March 2016 through December 2018. Fatigue was assessed using the functional assessment of chronic illness therapy-fatigue scoring system and defined as a score of 43 or less. We performed metabolomic analysis of serum samples using liquid chromatography-mass spectrometry methods and proteomic analysis using multiplex proximity extension assay (PEA) technology. Stool samples were obtained from 50 patients and analyzed by shotgun metagenomic sequencing on Illumina HiSeq platform.

RESULTS

Of the 166 study participants, 91 (55%) were fatigued. Serum samples from patients with fatigue (n = 59) did not have significant increases in levels of inflammatory cytokines compared with serum samples from nonfatigued patients (n = 72). We found a statistically significant difference in a cluster of 18 serum metabolites between patients with fatigue (n = 84) vs without fatigue (n = 72) (P = .033); serum samples from patients with fatigue had significant reductions in levels of methionine (P = .020), tryptophan (P = .042), proline (P = .017), and sarcosine (P = .047). Fecal samples from patients with fatigue had a less diverse gut microbiome, with significant reductions in butyrate-producing bacteria, including Faecalibacterium prausnitzii (P = .0002, q =.007) and Roseburia hominis (P = .0079, q = 0.105). This fatigue-like microbiome was associated with fatigue scales and correlated with progressive depletion of metabolites from serum samples.

CONCLUSIONS

In an analysis of fecal and serum samples from 166 patients with IBD, we found alterations in serum metabolites and fecal microbes that were associated with fatigue.

Validation of the diagnosis of eosinophilic esophagitis based on histopathology reports in Sweden

BACKGROUND

Eosinophilic esophagitis (EoE) is a relatively new diagnosis, where until recently a specific international classification of disease code was missing. One way to identify patients with EoE is to use histopathology codes. We validated the clinicopathological EoE diagnosis based on histopathology reports and patient charts to establish these data sources as the basis for a nationwide EoE patient cohort.

METHODS

Through the Epidemiology Strengthened by histoPathology Reports in Sweden (ESPRESSO) study, we randomly selected 165 patients from five Swedish health care regions with a histopathologic diagnosis of EoE. Patients were assigned a histopathology diagnosis of EoE if they had ≥15 eosinophils per high-power field or, in the absence of eosinophil quantification, the pathologist interpreted the biopsy as consistent with EoE. Patient charts were scrutinized to see if the other diagnostic criteria were fulfilled. Of the 131 received patient charts, 111 (85%) had sufficient information to be included in the study.

RESULTS

Of the 111 validated patients, 99 had EoE, corresponding to a positive predictive value of 89% (95% confidence interval = 82-94%). Dysphagia was the most common symptom (n = 78, 70%), followed by food impaction (n = 64, 58%) and feeding difficulties (n = 37, 33%). Twelve patients had coexisting asthma (11%) and 16 allergic rhinitis (14%). Seventeen patients underwent esophageal dilatation (15%), of which seven had more than one dilatation. Ninety-seven (87%) patients had a proton-pump inhibitor treatment ≤2 years before or after the diagnosis. Forty-two patients (38%) had been prescribed inhalation steroids and 64 (58%) had undergone esophageal radiology.

CONCLUSION

Histopathology reports from the ESPRESSO cohort with esophageal eosinophilic inflammation are suggestive of EoE.

Mortality in Eosinophilic Esophagitis - a nationwide, population-based matched cohort study from 2005 to 2017

BACKGROUND

There is a lack of knowledge about mortality in eosinophilic esophagitis (EoE). Therefore, this study aimed to examine the mortality in EoE.

METHODS

A nationwide, population-based matched cohort study was conducted of all EoE patients in Sweden diagnosed between July 2005 and December 2017. Individuals with EoE (n = 1,625) were identified through prospectively recorded histopathology codes from all gastrointestinal pathology reports in Sweden, representing 28 pathology departments (the ESPRESSO study). Each individual with EoE was then matched with up to five reference individuals from the general population (n = 8,003) for age, sex, year of birth, and place of residence. We used the Cox proportional hazard modeling to estimate the adjusted hazard ratio (aHR) and 95% confidence interval (95% CI) while adjusting for other potential confounders. In sensitivity analyses, mortality in EoE patients was compared with mortality in their siblings.

RESULTS

Through December 2017, 34 deaths were confirmed in EoE patients (4.60 per 1,000 person-years) compared with 165 in reference individuals (4.57 per 1,000 person-years). This rate corresponds to an aHR of 0.97 (95% CI = 0.67-1.40). HRs were similar in males (aHR = 1.00 [0.66-1.51]) and females (aHR = 0.92 [0.38-2.18]). We observed no increased risk in mortality due to esophageal or other gastrointestinal cancers in patients with EoE (aHR = 1.02 [0.51-2.02]).Mortality was similar in EoE patients and their siblings (aHR = 0.91 [0.44-1.85]).

CONCLUSION

In this nationwide, population-based matched cohort study in Sweden, there was no increased risk of death in patients with EoE compared with their siblings and the general population.

Assessment of Body Weight Changes in Patients with Inflammatory Bowel Diseases Initiating Biologic Therapy: A Prospective Cohort Study

BACKGROUND

Prior studies have inconsistently suggested that biologic therapy may be associated with weight gain in inflammatory bowel disease patients (IBD). Our aim was to compare weight gain across different biologic therapy classes with distinct mechanisms of action.

METHODS

This prospective cohort study recruited patients with moderate to severe IBD initiating outpatient biologic therapy with anti-TNF (infliximab, adalimumab), vedolizumab, or ustekinumab. Weight measurements were performed at weeks 0, 14, 30, and 54. Changes in weight between baseline and each of the follow-up visits were modeled as a continuous variable, and multivariate regression assessed the independent effect of therapeutic class on this outcome.

RESULTS

Our study enrolled 269 patients (163 CD, 106 UC) initiating biologic therapy [99 anti-TNF (37%), 122 vedolizumab (45%), 48 ustekinumab (18%)]. From baseline, the weight significantly increased at week 14 with a mean of 0.36 kg (± 3.8 kg, p = 0.004) and continued to increase compared to baseline with 0.96 kg (± 3.9 kg, p < 0.001) and 1.29 kg (± 4.2 kg, p < 0.001) at week 30 and 54, respectively. On univariate and multivariable analysis, no significant differences between any of the biologic therapies for weight gain were seen at any time point (weight gain anti-TNF: 0.31 kg, 1.06 kg, 1.33 kg; VDZ: 0.30 kg, 0.83 kg, 1.10 kg; UST: 0.63 kg, 1.21 kg, 2.31 kg at wk 14, wk 30, and wk 54, respectively). None of the disease activity parameters showed any statistical association with weight gain.

CONCLUSION

There was no difference in weight gain among the different biologic therapeutic classes.

Effect of Low-dose and Standard-dose Aspirin on PGE2 Biosynthesis Among Individuals with Colorectal Adenomas: A Randomized Clinical Trial

Low-dose aspirin is recommended by the U.S. Preventive Services Task Force for primary prevention of colorectal cancer in certain individuals. However, broader implementation will require improved precision prevention approaches to identify those most likely to benefit. The major urinary metabolite of PGE2, 11α-hydroxy-9,15-dioxo-2,3,4,5-tetranor-prostane-1,20-dioic acid (PGE-M), is a biomarker for colorectal cancer risk, but it is unknown whether PGE-M is modifiable by aspirin in individuals at risk for colorectal cancer. Adults (N = 180) who recently underwent adenoma resection and did not regularly use aspirin or NSAIDs were recruited to a double-blind, placebo-controlled, randomized trial of aspirin at 81 or 325 mg/day for 8-12 weeks. The primary outcome was postintervention change in urinary PGE-M as measured by LC/MS. A total of 169 participants provided paired urine samples for analysis. Baseline PGE-M excretion was 15.9 ± 14.6 (mean ± S.D, ng/mg creatinine). Aspirin significantly reduced PGE-M excretion (-4.7 ± 14.8) compared with no decrease (0.8 ± 11.8) in the placebo group (P = 0.015; mean duration of treatment = 68.9 days). Aspirin significantly reduced PGE-M levels in participants receiving either 81 (-15%; P = 0.018) or 325 mg/day (-28%; P < 0.0001) compared with placebo. In 40% and 50% of the individuals randomized to 81 or 325 mg/day aspirin, respectively, PGE-M reduction reached a threshold expected to prevent recurrence in 10% of individuals. These results support that aspirin significantly reduces elevated levels of PGE-M in those at increased colorectal cancer risk to levels consistent with lower risk for recurrent neoplasia and underscore the potential utility of PGE-M as a precision chemoprevention biomarker. The ASPIRED trial is registered as NCT02394769.

Intra- and Inter-cellular Rewiring of the Human Colon during Ulcerative Colitis

Genome-wide association studies (GWAS) have revealed risk alleles for ulcerative colitis (UC). To understand their cell type specificities and pathways of action, we generate an atlas of 366,650 cells from the colon mucosa of 18 UC patients and 12 healthy individuals, revealing 51 epithelial, stromal, and immune cell subsets, including BEST4⁺ enterocytes, microfold-like cells, and IL13RA2⁺IL11⁺ inflammatory fibroblasts, which we associate with resistance to anti-TNF treatment. Inflammatory fibroblasts, inflammatory monocytes, microfold-like cells, and T cells that co-express CD8 and IL-17 expand with disease, forming intercellular interaction hubs. Many UC risk genes are cell type specific and co-regulated within relatively few gene modules, suggesting convergence onto limited sets of cell types and pathways. Using this observation, we nominate and infer functions for specific risk genes across GWAS loci. Our work provides a framework for interrogating complex human diseases and mapping risk variants to cell types and pathways.

Longitudinal Trajectory of Fatigue With Initiation of Biologic Therapy in Inflammatory Bowel Diseases: A Prospective Cohort Study

BACKGROUNDS AND AIMS

Fatigue is prevalent in patients with inflammatory bowel diseases [IBD]. Biologic therapy is effective in achieving symptomatic and endoscopic remission, but its impact on fatigue is less well established. Our aim is to define the longitudinal trajectory of fatigue over 1 year in patients initiating biologic therapy.

METHODS

This prospective cohort enrolled patients diagnosed with Crohn's disease [CD] or ulcerative colitis [UC] initiating biologic therapy with infliximab, adalimumab, ustekinumab, or vedolizumab. Fatigue was quantified using the seven-point fatigue question in the Short Inflammatory Bowel Disease Questionnaire [SIBDQ]. A score of ≤4 for this question was used to define fatigue. Multivariable regression models adjusting for relevant confounders examined the independent association between attaining clinical remission and resolution of fatigue.

RESULTS

Our study included 326 patients [206 CD, 120 UC] initiating biologic therapy [144 anti-tumour necrosis factor, 129 vedolizumab, 63 ustekinumab]. A total of 61% of the included patients reported significant fatigue at baseline. This was associated with female gender, depressive symptoms, active disease, and disturbed sleep [p < 0.001]. Among the 198 patients who were fatigued at therapy initiation, 86 [70%], 55 [63%], and 44 [61%] remained fatigued at Week 14, 30, and 54, respectively. At each of these time points, achieving clinical remission was associated with lower likelihood of persistent fatigue. However, despite achieving remission, 35%, 30%, and 28% of patients experienced persistent fatigue at Week 14, 30, and 54, respectively.

CONCLUSIONS

Fatigue is common in IBD. Though biologic therapy improves fatigue parallel symptomatic improvement, a significant proportion continue to experience persistent fatigue up to 1 year.

A miniaturized, tethered, spectrally-encoded confocal endomicroscopy capsule

BACKGROUND AND OBJECTIVE

The tethered spectrally-encoded confocal endomicroscopy (SECM) capsule is an imaging device that once swallowed by an unsedated patient can visualize cellular morphologic changes associated with gastrointestinal (GI) tract diseases in vivo. Recently, we demonstrated a tethered SECM capsule for counting esophageal eosinophils in patients with eosinophilic esophagitis (EoE) in vivo. Yet, the current tethered SECM capsule is far too long to be widely utilized for imaging pediatric patients, who constitute a major portion of the EoE patient population. In this paper, we present a new tethered SECM capsule that is 33% shorter, has an easier and repeatable fabrication process, and produces images with reduced speckle noise.

MATERIALS AND METHODS

The smaller SECM capsule utilized a miniature condenser to increase the fiber numerical aperture and reduce the capsule length. A custom 3D-printed holder was developed to enable easy and repeatable device fabrication. A dual-clad fiber (DCF) was used to reduce speckle noise.

RESULTS

The fabricated SECM capsule (length = 20 mm; diameter = 7 mm) had a similar size and shape to a pediatric dietary supplement pill. The new capsule achieved optical sectioning thickness of 13.2 μm with a small performance variation between devices of 1.7 μm. Confocal images of human esophagus obtained in vivo showed the capability of this new device to clearly resolve microstructural epithelial details with reduced speckle noise.

CONCLUSIONS

We expect that the smaller size and better image performance of this new SECM capsule will greatly facilitate the clinical adoption of this technology in pediatric patients and will enable more accurate assessment of EoE-suspected tissues. Lasers Surg. Med. 51:452-458, 2019. © 2019 Wiley Periodicals, Inc.

Second-Look Endoscopy in Hospitalized Severe Ulcerative Colitis: A Retrospective Cohort Study

BACKGROUND

Acute severe ulcerative colitis (ASUC) is a serious complication of ulcerative colitis (UC). Management of partial responders to steroids or rescue therapy remains challenging. Whether there is a role for re-look sigmoidoscopic evaluation in disease management is unknown.

METHODS

Our study cohort consisted of patients who underwent 2 sigmoidoscopic procedures during the same index hospitalization for ASUC at our center. Reasons for repeat endoscopic evaluation and endoscopic and histologic severity of inflammation during both procedures were noted. Multivariable regression models were performed to identify predictors of improvement at the second endoscopic assessment and to determine the independent effect of such an improvement on in-hospital colectomy and at 3, 6, and 12 months.

RESULTS

Our study included 49 patients (mean age, 42 years; 52% women). Just under one-third of patients (30%) were noted to have improved endoscopic appearance at the second sigmoidoscopy, at a median of 9 days after initial exam. None of the patients who had improvement on the second endoscopy underwent in-hospital colectomy, compared with 46% of those with worsening or persistent disease (P = 0.002). Similar differences in the improved group persisted at 3 months (P = 0.007) and 6 months (P = 0.027). Histologic severity at the first endoscopy was associated with increased risk of colectomy in-hospital (odds ratio, 3.8; 95% confidence interval, 1.02-14.21) and at 3 and 6 months.

CONCLUSIONS

After a median interval of 9 days, endoscopic improvement was noted in 30% of patients with ASUC undergoing a second sigmoidoscopy, which predicted lower rates of colectomy in-hospital and at 3 and 6 months.

Increased frequency of systemic pro-inflammatory Vδ1+ γδ T cells in HIV elite controllers correlates with gut viral load

γδ T cells predominate in the intestinal mucosa and help maintain gut homeostasis and mucosal immunity. Although HIV infection significantly alters these cells, what drives these perturbations is unclear. Growing evidence suggests that impaired intestinal immune function in HIV leads to chronic immune activation and disease progression. This occurs even in HIV controllers - individuals with undetectable HIV viremia without antiretroviral therapy (ART). We show that Vδ1⁺ cells, a subset of γδ T cells described as being important in intestinal barrier function, increase in frequency in HIV-infected individuals, including HIV controllers. These cells resemble terminally differentiated effector memory cells, producing the pro-inflammatory cytokines IFNγ, TNFα, and MIP-1β upon stimulation. Importantly, pro-inflammatory Vδ1⁺ cell frequency correlates with levels of HIV RNA in intestinal tissue but not in plasma. This study supports a model in which local viral replication in the gut in HIV controllers disrupts the phenotype and function of Vδ1⁺ cells, a cell type involved in the maintenance of epithelial barrier integrity, and may thereby contribute to systemic immune activation and HIV disease progression.

Long-Term Outcomes of Immunosuppression-Naïve Steroid Responders Following Hospitalization for Ulcerative Colitis

BACKGROUND

Requirement for hospitalization in ulcerative colitis (UC) is a marker of severity of disease. However, the paradigm of when to escalate therapy in such patients and the benefits of early immunomodulator initiation is less well established.

AIM

To examine the benefits of early therapy escalation in immunosuppression-naïve patients hospitalized with severe ulcerative colitis responsive to steroids.

METHODS

We identified hospitalized UC patients who were immunosuppression naïve at index hospitalization and responded to intravenous steroids, not requiring medical or surgical rescue therapy. The 'therapy escalated' group comprised of those who were initiated on immunomodulators within 3 months of hospitalization. The need for colectomy at 12 months was compared to the 'not escalated' group who remained on non-immunosuppressive therapy.

RESULTS

Among 133 immunosuppressive naïve patients hospitalized for ulcerative colitis, 13 (9.8%) who responded to intravenous steroids and did not require rescue therapy underwent colectomy by 1 year. Among 123 patients who escalated to either immunomodulators (n = 46, 37%) or remained on non-immunosuppressive therapy (92% on 5-ASA), there was no difference in the need for colectomy at 1 year (10.8 vs. 7.8%; multivariate OR 1.29, 95% CI 0.35-4.74). There was also no difference in the time to colectomy between the two groups (p = 0.55).

CONCLUSION

Immunosuppression-naïve ASUC patients who respond to intravenous steroids remain at risk for colectomy. Immunomodulator initiation by 3 months did not reduce risk of colectomy at 1 year. There is an important need for prospective studies identifying thresholds for therapy escalation in UC.

Genetic Markers Predict Primary Nonresponse and Durable Response to Anti-Tumor Necrosis Factor Therapy in Ulcerative Colitis

BACKGROUND

Despite a high nonresponse rate, predictors of response to anti-tumor necrosis factor (anti-TNF) therapy in ulcerative colitis (UC) remain limited. We aim to determine clinical and genetic predictors of primary nonresponse (PNR) and durable response (DR) to anti-TNF therapy in a large prospective UC cohort.

METHODS

Using the Illumina Immunochip, candidate polymorphisms associated with clinical outcomes of PNR and DR were separately evaluated and combined into weighted genetic risk scores. Combined genetic and clinical multivariable models for PNR and DR were compared with clinical predictive models using area under the receiver operating characteristic (AUROC) curves. Models were internally (DR) or externally (PNR) validated. Multivariable logistic regression was utilized to assess the association of genetic risk scores with infliximab levels and antibodies.

RESULTS

Of 231 patients, 28 (12%) experienced PNR and 120 (52%) experienced DR. There was no significant difference in clinical features between primary nonresponders and responders. Eight alleles were associated with PNR. A combined clinical-genetic model (AUROC, 0.87) more accurately predicted PNR compared with a clinical-only model (AUROC, 0.57; P < 0.0001). In an external cohort of 131 patients, increasing tertiles of PNR genetic risk score correlated with increased risk of PNR (P = 0.052). Twelve candidate loci were associated with DR. Genetic risk score quartiles for DR demonstrated a strong dose-response relationship in predicting treatment duration. Genetic risk scores for PNR and DR were not associated with infliximab levels or antibody formation.

CONCLUSION

Genetic polymorphisms enhance prediction of PNR and DR to anti-TNF therapy in patients with UC.

Differences in Clinical Course, Genetics, and the Microbiome Between Familial and Sporadic Inflammatory Bowel Diseases

BACKGROUND AND AIM

Family history is the strongest risk factor for developing Crohn's disease [CD] or ulcerative colitis [UC]. We investigated whether the proximity of relationship with the affected relative and concordance for type of inflammatory bowel disease [IBD] modifies the effect of family history on phenotype and disease severity.

METHOD

This cross-sectional study included patients with a confirmed diagnosis of IBD in a clinical registry. Family history of IBD was assessed by a questionnaire ascertaining presence of disease in a first-first-degree, second-second-degree or distant relative. Our primary outcomes were disease phenotype as per the Montreal classification and severity measured by need for immunomodulator, biologic, or surgical therapy. Genotyping was performed on the Immunochip and faecal samples were subjected to 16S rRNA microbiome sequencing.

RESULTS

Our study included 2136 patients with IBD [1197 CD, 939 UC]. Just under one-third [32%] of cases ere familial IBD [17% first-degree, 21% second-degree]. Familial IBD was diagnosed at an earlier age, both in CD [26 vs 28 years, p = 0.0006] and UC [29 vs 32 years, p = 0.01]. Among CD patients, a positive family history for CD was associated with an increased risk for complicated disease in the presence of an affected family member (odds ratio [OR] 1.48, 95% confidence interval [CI] 1.07-2.03). However, this effect was significant only for first-degree relatives [OR 1.82, 95% CI 1.19-2.78].

CONCLUSIONS

A family history of CD in first-degree relatives was associated with complicated CD. Family history discordant for type of IBD or in distant relatives did not influence disease phenotype or natural history.

Gut Microbiome Function Predicts Response to Anti-integrin Biologic Therapy in Inflammatory Bowel Diseases

The gut microbiome plays a central role in inflammatory bowel diseases (IBDs) pathogenesis and propagation. To determine whether the gut microbiome may predict responses to IBD therapy, we conducted a prospective study with Crohn's disease (CD) or ulcerative colitis (UC) patients initiating anti-integrin therapy (vedolizumab). Disease activity and stool metagenomes at baseline, and weeks 14, 30, and 54 after therapy initiation were assessed. Community α-diversity was significantly higher, and Roseburia inulinivorans and a Burkholderiales species were more abundant at baseline among CD patients achieving week 14 remission. Several significant associations were identified with microbial function; 13 pathways including branched chain amino acid synthesis were significantly enriched in baseline samples from CD patients achieving remission. A neural network algorithm, vedoNet, incorporating microbiome and clinical data, provided highest classifying power for clinical remission. We hypothesize that the trajectory of early microbiome changes may be a marker of response to IBD treatment.

Attaching-and-Effacing Pathogens Exploit Junction Regulatory Activities of N-WASP and SNX9 to Disrupt the Intestinal Barrier

BACKGROUND & AIMS

Neural Wiskott-Aldrich Syndrome protein (N-WASP) is a key regulator of the actin cytoskeleton in epithelial tissues and is poised to mediate cytoskeletal-dependent aspects of apical junction complex (AJC) homeostasis. Attaching-and-effacing (AE) pathogens disrupt this homeostasis through translocation of the effector molecule early secreted antigenic target-6 (ESX)-1 secretion-associated protein F (EspF). Although the mechanisms underlying AJC disruption by EspF are unknown, EspF contains putative binding sites for N-WASP and the endocytic regulator sorting nexin 9 (SNX9). We hypothesized that N-WASP regulates AJC integrity and AE pathogens use EspF to induce junction disassembly through an N-WASP- and SNX9-dependent pathway.

METHODS

We analyzed mice with intestine-specific N-WASP deletion and generated cell lines with N-WASP and SNX9 depletion for dynamic functional assays. We generated EPEC and Citrobacter rodentium strains complemented with EspF bearing point mutations abolishing N-WASP and SNX9 binding to investigate the requirement for these interactions.

RESULTS

Mice lacking N-WASP in the intestinal epithelium showed spontaneously increased permeability, abnormal AJC morphology, and mislocalization of occludin. N-WASP depletion in epithelial cell lines led to impaired assembly and disassembly of tight junctions in response to changes in extracellular calcium. Cells lacking N-WASP or SNX9 supported actin pedestals and type III secretion, but were resistant to EPEC-induced AJC disassembly and loss of transepithelial resistance. We found that during in vivo infection with AE pathogens, EspF must bind both N-WASP and SNX9 to disrupt AJCs and induce intestinal barrier dysfunction.

CONCLUSIONS

Overall, these studies show that N-WASP critically regulates AJC homeostasis, and the AE pathogen effector EspF specifically exploits both N-WASP and SNX9 to disrupt intestinal barrier integrity during infection.

Clinical Predictors and Natural History of Disease Extension in Patients with Ulcerative Proctitis

BACKGROUND

A proportion of patients with initial presentation of ulcerative proctitis (UP) progress to more extensive colitis. We sought to characterize the natural history and identify clinical predictors of extension in UP.

METHODS

We performed a retrospective cohort study of participants with a new diagnosis of UP from January 2000 to December 2015. We used Cox proportional hazard modeling to identify predictors of disease extension.

RESULTS

We identified 169 new cases of UP with a median age of diagnosis of 40 years (range: 16-91 yr) and a median follow-up of 4.3 years (range: 3.3-15.1 yr). Fifty-three (31%) patients developed extension over the follow-up time. Compared with nonextenders, the need for immunosuppressive or biologic therapy was significantly higher among extenders (34% versus 2.6%, P < 0.001). In multivariable analyses, compared with UP cases with body mass index <25, the adjusted hazard ratios of extension were 1.75 (95% confidence interval [CI], 0.95-3.23) and 2.77 (95% CI, 1.07-7.14) among overweight and obese patients, respectively (Ptrend = 0.03). Similarly, patients with a history of appendectomy or endoscopic finding of moderate to severe disease had a higher risk of extension (adjusted hazard ratio = 2.74, 95% CI, 1.07-7.01 and 1.96, 95% CI, 1.05-3.67, respectively).

CONCLUSIONS

In a retrospective cohort study, we show that appendectomy, body mass index, and endoscopic activity at the time of diagnosis of proctitis are associated with an increased risk of extension. In addition, our data suggest that extenders are more likely to require immunosuppressive or biologic therapy.

Dietary Iron and Heme Iron Consumption, Genetic Susceptibility, and Risk of Crohn's Disease and Ulcerative Colitis

BACKGROUND

Dietary iron and heme, likely through their effect on gut commensal bacteria and colonic barrier function, have been shown to modulate colonic inflammation in animal models of colitis. Nonetheless, the link between dietary total and heme iron and risk of Crohn's disease (CD) and ulcerative colitis (UC) has not been previously explored.

METHODS

We conducted a prospective cohort study of 165,331 U.S. women enrolled in the Nurses' Health Study and Nurses' Health Study II. Dietary information was collected using a validated food frequency questionnaire at baseline (1984) and updated every 2 to 4 years. Self-reported CD and UC diagnoses were confirmed through medical records review. We used Cox proportional hazard models to calculate hazard ratios and 95% confidence intervals while adjusting for potential confounders. In a case-control study nested within these cohorts, we evaluated the interaction between single-nucleotide polymorphisms associated with genome-wide susceptibility to CD and UC and dietary total and heme iron intake on risk of CD and UC using logistic regression modeling.

RESULTS

Through 2011, over 3,038,049 person-years of follow-up, we documented 261 incident cases of CD and 321 incident cases of UC. Dietary heme iron was nonsignificantly associated with increased risk of UC (Ptrend = 0.12). This association seemed to be modified by the UC susceptibility locus, rs1801274, a coding variant in the FcγRIIA gene (Pinteraction = 7.00E-05). In contrast, there was no association between dietary heme iron and risk of CD (Ptrend = 0.67). We also did not observe an association between total dietary intake of iron and risk of CD or UC (All Ptrend > 0.35).

CONCLUSION

In 2 large prospective cohort studies, dietary total and heme iron were not associated with risk of CD or UC. Our suggestive finding that the association between dietary heme iron intake and risk of UC may be modified by a coding variant in FcγRIIA gene warrants additional investigation.

The impact of co-existing immune-mediated diseases on phenotype and outcomes in inflammatory bowel diseases

BACKGROUND

Inflammatory bowel diseases lead to progressive bowel damage and need for surgery. While the increase in prevalence of other immune-mediated diseases in IBD is well recognised, the impact of this on the natural history of IBD is unknown.

AIM

To determine the impact of concomitant immune-mediated diseases on phenotypes and outcomes in IBD.

METHODS

Patients with IBD enrolled in a prospective registry were queried about the presence of other immune-mediated diseases, defined as those where immune dysregulation plays a role in pathogenesis. Demographics and disease-related information were obtained. Subjects also completed measures of quality of life. Multivariable regression models compared disease phenotype and outcomes of IBD patients with and without other immune-mediated diseases.

RESULTS

The cohort included 2145 IBD patients among whom 458 (21%) had another immune-mediated disease. There was no difference in CD phenotype between the two groups. UC patients were more likely to have pancolitis in the presence of another immune-mediated disease (62%) compared to those without (52%, P = 0.02). IBD patients with another immune-mediated disease had higher rates of needing anti-TNF biologics [Odds ratio (OR) 1.31, 95% CI 1.05-1.63] and surgery (OR 1.26, 95% CI 0.99-1.61). The presence of another immune-mediated disease was also associated with lower disease-specific and general physical quality of life.

CONCLUSIONS

The presence of another immune-mediated disease in IBD patients was associated with higher likelihood of pancolonic involvement in UC, and a modest increase in need for IBD-related surgery and anti-TNF biological therapy. Such patients also experienced worse quality of life.

Older Age- and Health-related Quality of Life in Inflammatory Bowel Diseases

BACKGROUND

The burden of inflammatory bowel disease (IBD) in the older population is increasing. Older-onset disease is associated with reduced use of immunosuppressive medications. In addition, older patients may be more vulnerable to the effect of disease-related symptoms and consequently may experience worse health-related quality of life (HRQoL) compared with younger patients.

METHODS

This prospective study included a cohort of patients with Crohn's disease and ulcerative colitis recruited from a single center. All patients completed the Short Inflammatory Bowel Disease Questionnaire (SIBDQ) and the short form-12 (SF-12) questionnaire yielding general physical health (PCS) and mental health component scale subscores (MCS). Patients older than 60 years were compared with those younger than 60 years using multivariable regression analysis.

RESULTS

Our study included 1607 patients, among whom 186 were older than 60 at the time of assessment. Older patients were more likely to have isolated colonic disease and less likely to use immunosuppressive therapy. On multivariable analysis, older patients with IBD had higher SIBDQ (2.34, 95% confidence interval, 0.82-3.87) and SF-12 mental subscores (3.78, 95% confidence interval, 2.26-5.30), but lower physical HRQoL (-1.80, 95% confidence interval, -3.21 to -0.38). There was no difference in the SIBDQ and PCS scores between older patients and newly diagnosed IBD or with established disease.

CONCLUSIONS

Older age was associated with modestly higher SIBDQ and mental HRQoL scores, but lower physical HRQoL. Comprehensive care of the older patient with IBD should include assessment of factors impairing physical quality of life to ensure appropriate interventions.

ASPirin Intervention for the REDuction of colorectal cancer risk (ASPIRED): a study protocol for a randomized controlled trial

BACKGROUND

Although aspirin is recommended for the prevention of colorectal cancer, the specific individuals for whom the benefits outweigh the risks are not clearly defined. Moreover, the precise mechanisms by which aspirin reduces the risk of cancer are unclear. We recently launched the ASPirin Intervention for the REDuction of colorectal cancer risk (ASPIRED) trial to address these uncertainties.

METHODS/DESIGN

ASPIRED is a prospective, double-blind, multidose, placebo-controlled, biomarker clinical trial of aspirin use in individuals previously diagnosed with colorectal adenoma. Individuals (n = 180) will be randomized in a 1:1:1 ratio to low-dose (81 mg/day) or standard-dose (325 mg/day) aspirin or placebo. At two study visits, participants will provide lifestyle, dietary and biometric data in addition to urine, saliva and blood specimens. Stool, grossly normal colorectal mucosal biopsies and cytology brushings will be collected during a flexible sigmoidoscopy without bowel preparation. The study will examine the effect of aspirin on urinary prostaglandin metabolites (PGE-M; primary endpoint), plasma inflammatory markers (macrophage inhibitory cytokine-1 (MIC-1)), colonic expression of transcription factor binding (transcription factor 7-like 2 (TCF7L2)), colonocyte gene expression, including hydroxyprostaglandin dehydrogenase 15-(NAD) (HPGD) and those that encode Wnt signaling proteins, colonic cellular nanocytology and oral and gut microbial composition and function.

DISCUSSION

Aspirin may prevent colorectal cancer through multiple, interrelated mechanisms. The ASPIRED trial will scrutinize these pathways and investigate putative mechanistically based risk-stratification biomarkers.

TRIAL REGISTRATION

This protocol is registered with the U.S. National Institutes of Health trial registry, ClinicalTrials.gov, under the identifier NCT02394769 . Registered on 16 March 2015.

Identification and Characterization of a Novel Association between Dietary Potassium and Risk of Crohn's Disease and Ulcerative Colitis

Background

Recent animal studies have identified that dietary salt intake may modify the risk and progression of autoimmune disorders through modulation of the IL-23/T_H17 pathway, which is critical in the pathogenesis of ulcerative colitis (UC) and Crohn’s disease (CD).

Methods

We conducted a prospective study of U.S. women enrolled in the Nurses’ Health Study (NHS) and NHSII who provided detailed and validated information on diet and lifestyle beginning in 1984 in NHS and 1991 in NHSII. We confirmed incident cases of UC and CD reported through 2010 in NHS and 2011 in NHSII. We used Cox proportional hazards models to calculate hazard ratios and 95% confidence intervals. In a case–control study nested within these cohorts, we evaluated the interaction between single nucleotide polymorphisms (SNPs) in genes involved in T_H17 pathway and dietary potassium on risk of CD and UC. In a cohort of healthy volunteers, we also assessed the effect of supplemental potassium on development of naïve and memory T cells, differentiated with TGFβ1 or T_H17 conditions.

Results

Among a total of 194,711 women over a follow-up of 3,220,247 person-years, we documented 273 cases of CD and 335 cases of UC. Dietary intake of potassium (P_trend = 0.005) but not sodium (P_trend = 0.44) was inversely associated with risk of CD. Although, both dietary potassium and sodium were not significantly associated with risk of UC, there was a suggestion of an inverse association with dietary potassium (P_trend = 0.08). The association of potassium with risk of CD and UC appeared to be modified by loci involved in the T_H17 pathway that have previously been associated with susceptibility to CD, particularly SNP rs7657746 (IL21) (P_interaction = 0.004 and 0.01, respectively). In vitro, potassium enhanced the expression of Foxp3 in both naïve and memory CD4+ T cells via activating Smad2/3 and inhibiting Smad7 in T_H17 cells.

Conclusion

Dietary potassium is inversely associated with risk of CD with both in vitro and gene–environment interaction data suggesting a potential role for potassium in regulating immune tolerance through its effect on Tregs and T_H17 pathway.

Implementation and adherence to osteoporosis screening guidelines among coeliac disease patients

BACKGROUND

There are no studies evaluating the implementation of American Gastroenterological Association (AGA) guidelines on osteoporosis screening in coeliac disease.

AIMS

To investigate implementation of osteoporosis screening guidelines in coeliac disease patients and determine how often bone mineral density (BMD) assessment leads to therapeutic intervention.

METHODS

We screened all patients with biopsy-proven coeliac disease at our center from 2003 to 2013 and collected data on indication and results of dual energy X-ray absorptiometry scanning (DXA) and therapeutic interventions.

RESULTS

Of 222 adults with coeliac, only 80 (36%) underwent DXA after their diagnosis. Of those, 43 had DXA for osteoporosis screening specifically related to their coeliac diagnosis. Of these 43 patients, 28 (65.1%) had low BMD. A therapeutic intervention was made in the majority of these patients (21/28, 75%). Of 330 pediatric coeliac cases, 52 (15.8%) had DXA specifically in the context of the coeliac disease diagnosis with only 5 being complicated coeliac disease. Of these, 3 (5.8%) had low BMD and only 2 underwent therapeutic intervention.

CONCLUSIONS

Osteoporosis screening guidelines are not followed in the majority of patients with coeliac disease but, when followed, frequently lead to therapeutic intervention. Osteoporosis screening guidelines in coeliac disease need to be updated, strengthened and publicized.

Hepatic Injury in Nonalcoholic Steatohepatitis Contributes to Altered Intestinal Permeability

BACKGROUND & AIMS

Emerging data suggest that changes in intestinal permeability and increased gut microbial translocation contribute to the inflammatory pathway involved in nonalcoholic steatohepatitis (NASH) development. Numerous studies have investigated the association between increased intestinal permeability and NASH. Our meta-analysis of this association investigates the underlying mechanism.

METHODS

A meta-analysis was performed to compare the rates of increased intestinal permeability in patients with NASH and healthy controls. To further address the underlying mechanism of action, we studied changes in intestinal permeability in a diet-induced (methionine-and-choline-deficient; MCD) murine model of NASH. In vitro studies were also performed to investigate the effect of MCD culture medium at the cellular level on hepatocytes, Kupffer cells, and intestinal epithelial cells.

RESULTS

Nonalcoholic fatty liver disease (NAFLD) patients, and in particular those with NASH, are more likely to have increased intestinal permeability compared with healthy controls. We correlate this clinical observation with in vivo data showing mice fed an MCD diet develop intestinal permeability changes after an initial phase of liver injury and tumor necrosis factor-α (TNFα) induction. In vitro studies reveal that MCD medium induces hepatic injury and TNFα production yet has no direct effect on intestinal epithelial cells. Although these data suggest a role for hepatic TNFα in altering intestinal permeability, we found that mice genetically resistant to TNFα-myosin light chain kinase (MLCK)-induced intestinal permeability changes fed an MCD diet still develop increased permeability and liver injury.

CONCLUSIONS

Our clinical and experimental results strengthen the association between intestinal permeability increases and NASH and also suggest that an early phase of hepatic injury and inflammation contributes to altered intestinal permeability in a fashion independent of TNFα and MLCK.

The ability of an attaching and effacing pathogen to trigger localized actin assembly contributes to virulence by promoting mucosal attachment

Enterohaemorrhagic Escherichia coli (EHEC) colonizes the intestine and causes bloody diarrhoea and kidney failure by producing Shiga toxin. Upon binding intestinal cells, EHEC triggers a change in host cell shape, generating actin 'pedestals' beneath bound bacteria. To investigate the importance of pedestal formation to disease, we infected genetically engineered mice incapable of supporting pedestal formation by an EHEC-like mouse pathogen, or wild type mice with a mutant of that pathogen incapable of generating pedestals. We found that pedestal formation promotes attachment of bacteria to the intestinal mucosa and vastly increases the severity of Shiga toxin-mediated disease.

Neural Wiskott-Aldrich syndrome protein modulates Wnt signaling and is required for hair follicle cycling in mice

The Rho family GTPases Cdc42 and Rac1 are critical regulators of the actin cytoskeleton and are essential for skin and hair function. Wiskott-Aldrich syndrome family proteins act downstream of these GTPases, controlling actin assembly and cytoskeletal reorganization, but their role in epithelial cells has not been characterized in vivo. Here, we used a conditional knockout approach to assess the role of neural Wiskott-Aldrich syndrome protein (N-WASP), the ubiquitously expressed Wiskott-Aldrich syndrome-like (WASL) protein, in mouse skin. We found that N-WASP deficiency in mouse skin led to severe alopecia, epidermal hyperproliferation, and ulceration, without obvious effects on epidermal differentiation and wound healing. Further analysis revealed that the observed alopecia was likely the result of a progressive and ultimately nearly complete block in hair follicle (HF) cycling by 5 months of age. N-WASP deficiency also led to abnormal proliferation of skin progenitor cells, resulting in their depletion over time. Furthermore, N-WASP deficiency in vitro and in vivo correlated with decreased GSK-3beta phosphorylation, decreased nuclear localization of beta-catenin in follicular keratinocytes, and decreased Wnt-dependent transcription. Our results indicate a critical role for N-WASP in skin function and HF cycling and identify a link between N-WASP and Wnt signaling. We therefore propose that N-WASP acts as a positive regulator of beta-catenin-dependent transcription, modulating differentiation of HF progenitor cells.