Esomeprazole induces upper gastrointestinal tract transmucosal permeability increase

Long-term administration of omeprazole in mice: a study of behavior, inflammatory, and oxidative stress alterations with focus on central nervous system

Chronic use of omeprazole has been linked to central effects alongside with the global concern of increasing appearance of neuropsychiatric disorders. This study aimed to identifying behavioral, inflammatory, and oxidative stress alterations after long-term administration of omeprazole. C57BL/6 mice were divided in groups: OME and Sham, each received either solutions of omeprazole or vehicle, administered for 28 days by gavage. Results observed in the omeprazole-treated mice: Decrease in the crossing parameter in the open field, no change in the motor performance assessed by rotarod, an immobility time reduction in the forced swimming test, improved percentage of correct alternances in the Ymaze and an exploration time of the novel object reduction in the novel object recognition. Furthermore, a reduced weight gain and hippocampal weight were observed. There was an increase in the cytokine IL1-β levels in both prefrontal cortex (PFC) and serum, whereas TNF-α increased only in the PFC. Nitrite levels increased in the hippocampus (HP) and PFC, while malondialdehyde (MDA) and glutathione (GSH) levels decreased. These findings suggest that omeprazole improves depressive-like behavior and working memory, likely through the increase in nitrite and reduction in MDA levels in PFC and HP, whereas, the impairment of the recognition memory is more likely to be related to the reduced hippocampal weight. The diminished weight gain might be associated with the IL-1β increased levels in the peripheral blood. Altogether, omeprazole showed to have the potential to impact at central level and inflammatory and oxidative parameters might exert a role between it.

Gastric Acid Suppression Therapy and Its Association with Peritoneal Dialysis-Associated Peritonitis in the Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS)

Key Points

In a large multinational cohort of PD patients, any GAS use was not associated with an increased risk of all-organism peritonitis. For peritonitis, risks were particularly high among certain classes of organisms particularly for Gram-negative, enteric, and streptococcal peritonitis episodes. The association with enteric peritonitis appeared to be stronger among H2RA users.

Background

Peritonitis is a major peritoneal dialysis–related complication. We determined whether gastric acid suppression (GAS) (proton pump inhibitor [PPI] or histamine-2 receptor antagonists [H2RAs]) use was associated with all-cause and organism-specific peritonitis in peritoneal dialysis patients.

Methods

In the Peritoneal Dialysis Outcomes and Practice Patterns Study (595 facilities, eight countries, years 2014–2022), associations between GAS use and time to first episode of all-cause peritonitis were examined using Cox proportional hazards models. The primary exposure of interest was GAS and secondarily PPI or H2RA use. Secondary outcomes were organism-specific peritonitis, peritonitis cure rates, and death.

Results

Among patients (N =23,797) at study baseline, 6020 (25.3%) used PPIs, and 1382 (5.8%) used H2RAs. Overall risks of GAS use and peritonitis risk (adjusted hazard ratio [AHR]=1.05, 95% confidence interval [CI], 0.98 to 1.13]) and use of PPI (AHR 1.06 [95% CI, 0.99 to 1.14]) or H2RA (AHR 1.02 [95% CI, 0.88 to 1.18]) did not reach statistical significance. In organism-specific analyses, GAS users displayed higher peritonitis risks for Gram-negative (AHR 1.29, 95% CI, 1.05 to 1.57), Gram-positive (AHR 1.15, 95% CI, 1.01 to 1.31), culture-negative (AHR 1.20, 95% CI, 1.01 to 1.42), enteric (AHR 1.23, 95% CI, 1.03 to 1.48), and particularly Streptococcal (AHR 1.47, 95% CI, 1.15 to 1.89) peritonitis episodes. GAS was also associated with higher overall mortality (AHR 1.13 [95% CI, 1.05 to 1.22]).

Conclusion

The association between GAS use and peritonitis risk was weaker (hazard ratio [HR] 1.05 [0.98 to 1.13]) than for streptococcal (HR 1.57 [1.15 to 1.89]) and Gram-negative (HR 1.29 [1.05 to 1.57]) peritonitis. A better understanding of mechanisms surrounding the differential effects of GAS subtype on peritonitis risks is needed. Clinicians should be cautious when prescribing GAS. The impact of GAS deprescribing on peritonitis risk requires further evaluation.

Hospitalization Trends and Outcomes of Eosinophilic Esophagitis in the United States: A Decade-Long Nationwide Analysis

Background Eosinophilic esophagitis (EoE) is a chronic antigen-mediated esophageal disease characterized by infiltration of the esophageal mucosa by eosinophils. The prevalence of EoE continues to rise worldwide. However, certain aspects of the epidemiology and pathogenesis remain unclear. Methods This study examined the hospitalization trends of EoE using an extensive inpatient database in the United States, the National (Nationwide) Inpatient Sample (NIS), to identify hospitalizations between 2010 and 2019. We assessed patient demographics as well as hospital-specific variables using the NIS. We obtained the prevalence rate of EoE for each year and used joinpoint regression analysis to obtain trends after adjusting the rate for age and gender. We also sought to characterize the outcomes of these hospitalizations by obtaining the mortality rate, length of stay (LOS), and total hospital charges (THC). Results Of 305 million hospitalizations included in the study, 33,878 were for EoE. The prevalence rate per 100,000 hospitalizations of EoE increased from 6.6 in 2010 to 15.5 in 2019. The annual percentage change obtained from the joinpoint regression analysis was 13.3% from 2010 to 2014 and 7.2% from 2014 to 2019. Most of the hospitalizations were among the male gender and young adults. Almost 95% of hospitalizations across the study period were seen in urban hospitals. We did not notice any significant trend in the mortality rates or length of stay over the study period. The THC increased significantly across the study period. Conclusion There has been an upward trend in the average prevalence rate of EoE over the decade from 2010 to 2019 which almost parallels that of inflammatory bowel disease. This represents a significant burden of disease for a condition that was initially recognized in the late 20th century.

Rabeprazole destroyed gastric epithelial barrier function through FOXF1/STAT3-mediated ZO-1 expression

Rabeprazole is a representative of proton pump inhibitors and widely used in anti-ulcer treatment. However, the effect of Rabeprazole on gut barrier function remains to be identified. In this study, we show that ZO-1 expression is decreased in patients receiving Rabeprazole by immunofluorescence (IF) analysis. Western blotting (WB) and real-time PCR (qPCR) results demonstrate that Rabeprazole treatment leads to a significant downregulation of ZO-1 expression through inhibition of the FOXF1/STAT3 pathway, leading to destroy barrier function, which illustrates a novel pathway that Rabeprazole regulates barrier function in gastric epithelial cells. Mechanistically, Rabeprazole treatment led to a downregulation of STAT3 and FOXF1 phosphorylation, leading to inhibit nuclear translocation and decrease the binding of STAT3 and FOXF1 to ZO-1 promoter, respectively. Most important, endogenous FOXF1 interacted with STAT3, and this interaction was dramatically abolished by Rabeprazole stimulation. Overexpression of STAT3 and FOXF1 in GES-1 cells reversed the inhibitory effect of Rabeprazole on ZO-1 expression, respectively. These finding extended the function of Rabeprazole and established a previously unappreciated mechanism by which the Rabeprazole/FOXF1/STAT3 axis facilitated ZO-1 expression to regulate barrier function, and a comprehensive consideration and evaluation was required in treatment of patients.

Long-Term Use of Proton Pump Inhibitors Disrupts Intestinal Tight Junction Barrier and Exaggerates Experimental Colitis

BACKGROUND

Proton pump inhibitors [PPIs] are widely used to treat a number of gastro-oesophageal disorders. PPI-induced elevation in intragastric pH may alter gastrointestinal physiology. The tight junctions [TJs] residing at the apical intercellular contacts act as a paracellular barrier. TJ barrier dysfunction is an important pathogenic factor in inflammatory bowel disease [IBD]. Recent studies suggest that PPIs may promote disease flares in IBD patients. The role of PPIs in intestinal permeability is not clear.

AIM

The aim of the present study was to study the effect of PPIs on the intestinal TJ barrier function.

METHODS

Human intestinal epithelial cell culture and organoid models and mouse IBD models of dextran sodium sulphate [DSS] and spontaneous enterocolitis in IL-10-/- mice were used to study the role of PPIs in intestinal permeability.

RESULTS

PPIs increased TJ barrier permeability via an increase in a principal TJ regulator, myosin light chain kinase [MLCK] activity and expression, in a p38 MAPK-dependent manner. The PPI-induced increase in extracellular pH caused MLCK activation via p38 MAPK. Long-term PPI administration in mice exaggerated the increase in intestinal TJ permeability and disease severity in two independent models of DSS colitis and IL-10-/- enterocolitis. The TJ barrier disruption by PPIs was prevented in MLCK-/- mice. Human database studies revealed increased hospitalizations associated with PPI use in IBD patients.

CONCLUSIONS

Our results suggest that long-term use of PPIs increases intestinal TJ permeability and exaggerates experimental colitis via an increase in MLCK expression and activity.

Oral omeprazole and diclofenac intake is associated with increased faecal calprotectin levels: a randomised open-label clinical trial

BACKGROUND AND AIM

Nonsteroidal anti-inflammatory drugs and proton pump inhibitors are known to affect the diagnostics of gastrointestinal disorders. The aim of this study was to investigate to what extent omeprazole, diclofenac or co-administration of these affects faecal calprotectin levels and the normalisation interval after cessation.

METHODS

Participants received 20 mg omeprazole daily for 2 weeks in the first sequence, 50 mg oral diclofenac three times daily for 2 weeks in the second and co-administration of these for 2 weeks in the third, with washout periods in between. The first two sequences were randomised to a different order. Faecal calprotectin was measured on days 0, 4, 7, 14, 21, 28 and 35 and thereafter at 7-day intervals until normalisation in each sequence.

RESULTS

Thirty-two healthy volunteers were included. During drug intake, 39% on diclofenac (median 70.8 µg/g; range 50.2-1080 µg/g), 53% on omeprazole (median 85.3 µg/g; range 51.1-249 µg/g) and 69% on omeprazole + diclofenac (median 101.5 µg/g; range 51.5-532 µg/g) had faecal calprotectin levels above normal. In the diclofenac sequence, faecal calprotectin returned to normal in all participants within 2 weeks of cessation and in the omeprazole and co-administration sequences, within 3 weeks of cessation. No statistical significant difference was found with respect to drug order.

CONCLUSION

Short-term intake of omeprazole, diclofenac or co-administration appears to increase faecal calprotectin levels. In patients with increased faecal calprotectin on omeprazole alone or in combination with diclofenac, a repeated faecal calprotectin test is recommended at least 3 weeks after cessation. On diclofenac alone, it is sufficient to repeat the faecal calprotectin test 2 weeks after cessation.

Diagnosis and Management of Microscopic Colitis in Pediatric Patients

Microscopic colitis (MC) is an inflammatory disease of the colon, characterized by chronic watery diarrhea with distinguishing histologic findings despite normal endoscopic appearance of the colonic mucosa. MC is a common cause of diarrhea in older adults, though it has been infrequently reported in children and adolescents. As MC is rare in the pediatric population, and the clinical presentation is non-specific, increased awareness of this disease amongst pediatric clinicians and pathologists is essential for timely diagnosis, which requires performing colonoscopy with biopsy. The etiology of MC is incompletely understood, but current theories in pathogenesis inform management strategies. The goals of management in pediatric MC should be to achieve symptomatic improvement while minimizing adverse effects of treatment. Many patients who achieve clinical response have symptomatic recurrence after discontinuation of initial therapy, and may require maintenance medication therapy to sustain remission. This review aims to summarize the epidemiology and risk factors, clinical features, diagnosis, theories regarding pathogenesis, and suggested management approaches for MC in the pediatric population.

Are Proton Pump Inhibitors More Effective Than Histamine-2-Receptor Antagonists for Stress Ulcer Prophylaxis in Critically Ill Patients? A Systematic Review and Meta-Analysis of Cohort Studies

BACKGROUND

Histamine-2-receptor antagonists (H₂RAs) have been largely replaced by proton pump inhibitors (PPIs) for stress ulcer prophylaxis (SUP) despite the inconclusive evidence concerning comparative effectiveness.

OBJECTIVE

To compare the effectiveness of PPIs and H₂RAs on SUP in real-world setting.

METHODS

PubMed, Embase, and the Cochrane Library were searched from inception to September 19, 2021. We included cohort studies comparing PPIs with H₂RAs in critically ill adult patients and explicitly reporting the outcome of gastrointestinal (GI) bleeding or mortality. Newcastle-Ottawa Scale was used to assess potential risk of bias. We conducted a random-effects meta-analysis and only the studies with adjusted effect estimates were pooled. The Grading of Recommendations Assessment, Development, and Evaluation system was used to assess the overall quality of the evidence.

RESULTS

Thirteen cohort studies (N = 145 149) were eligible and 11 of them available for full texts were of low to moderate risk of bias. Meta-analysis of adjusted effect estimates indicated that PPIs were associated with a significantly higher risk of GI bleeding, compared with H₂RAs (8 studies, odds ratio [OR] = 1.98, 95% confidence interval [CI] = 1.30-3.01, low certainty). Post hoc pooling analysis also suggested that PPIs were associated with a slightly higher risk of mortality in comparison with H₂RAs (7 studies, OR = 1.27, 95% CI = 1.13-1.42, low certainty).

CONCLUSION AND RELEVANCE

The systematic review of cohort studies showed that PPIs were associated with higher risks of GI bleeding and mortality, although the certainty of evidence was low. Overall, we suggest not excluding H₂RAs for SUP, while further studies are essential for elucidating the risk stratification, optimal regimen, and specific duration.

Intestinal Barrier in Human Health and Disease

The intestinal mucosa provides a selective permeable barrier for nutrient absorption and protection from external factors. It consists of epithelial cells, immune cells and their secretions. The gut microbiota participates in regulating the integrity and function of the intestinal barrier in a homeostatic balance. Pathogens, xenobiotics and food can disrupt the intestinal barrier, promoting systemic inflammation and tissue damage. Genetic and immune factors predispose individuals to gut barrier dysfunction, and changes in the composition and function of the gut microbiota are central to this process. The progressive identification of these changes has led to the development of the concept of ‘leaky gut syndrome’ and ‘gut dysbiosis’, which underlie the relationship between intestinal barrier impairment, metabolic diseases and autoimmunity. Understanding the mechanisms underlying this process is an intriguing subject of research for the diagnosis and treatment of various intestinal and extraintestinal diseases.

Emerging incidence trends of eosinophilic esophagitis over 25 years: Results of a nationwide register-based pathology cohort

RATIONALE

Eosinophilic esophagitis (EoE) has emerged from a case-reportable illness in the early 1990s to a distinct clinicopathological entity. Increasing worldwide incidences have been observed, although due to various study designs estimates are inconsistent.

AIM

To determine population-based annual incidence rates over a time period of 25 years.

METHODS

A nationwide register-based pathology (PALGA) search was performed to identify reports describing esophageal eosinophilia between 1995 and 2019. EoE was identified if the diagnosis was confirmed by the pathologist. Crude incidence rates were estimated by the number of new EoE cases per year and matched with population data.

RESULTS

Between 1995 and 2019, 7361 unique patients' reports mentioned esophageal eosinophilia, of these 4061 were classified as EoE (71% male, mean age 37.9 ± 18.4 years). In total, 639 (16%) children (<18 years) were diagnosed. The EoE incidence increased from 0.01 in 1995 (95% CI: 0.0 - 0.04) to 3.16 (95% CI: 2.90 - 3.44) per 100.000 inhabitants in 2019. EoE was significantly more prevalent in males (OR 2.48 | 95% CI: 2.32 - 2.65; vs. females p < 0.001) and adults (OR 1.42 | 95% CI: 1.31 - 1.55; vs. children p < 0.001). Highest incidences were observed in 2019, being 4.37 (95% CI: 3.94 - 4.84) vs. 1.97 (95% CI: 1.68 - 2.29) per 100.000 males and females, respectively (p < 0.001). No seasonal variation was observed.

CONCLUSION

Over the past quarter century, the annual rates of newly diagnosed EoE patients raised dramatically and this increase has not reached a deceleration yet.

Impact of Overlapping Functional Gastrointestinal Disorders on the Quality of Life in Patients With Gastroesophageal Reflux Disease

Gastroesophageal reflux disease (GERD) and functional gastrointestinal disorders (FGIDs), including irritable bowel syndrome and functional dyspepsia, are common afflictions within the general population. Both conditions have a considerable impact on the daily health related quality of life (HRQoL) of affected individuals. Risk factors surrounding any impaired HRQoL in patients with GERD involve those of younger age, obesity, an increase in reflux symptom frequency, and overlapping FGIDs. The risk factors for subjects experiencing an overlap in FGIDs and GERD involve those who are female, younger age, cigarette smoking, non-erosive reflux disease, more GERD symptoms, and psychological performances including anxiety, somatization, and more frequent healthcareseeking behavior. The overlap of GERD and FGIDs is associated with a worsening of both physical and mental health, an increase in bothersome symptoms, impaired functional capacity, and a higher likelihood of consulting a physician. Acid secretion suppressors could offer therapeutic efficacy to some patients experiencing overlapping GERD and FGIDs.

Proton Pump Inhibitors Reduce Duodenal Eosinophilia, Mast Cells, and Permeability in Patients With Functional Dyspepsia

BACKGROUND & AIMS

Despite the growing recognition of duodenal alterations in the pathophysiology of functional dyspepsia (FD), the effect and mechanism of proton pump inhibitors (PPIs) or first-line therapy remain unclear. We studied duodenal and systemic alterations in relation to PPI therapy in patients with FD and healthy volunteers (HVs).

METHODS

We performed a prospective interventional study assessing symptoms (Patient Assessment of Gastrointestinal Symptom Severity Index), duodenal alterations, and systemic factors in patients with FD ("FD-starters") and HVs before and after PPI therapy (pantoprazole 40 mg once daily for 4 weeks). Duodenal mucosal eosinophils, mast cells and permeability were quantified. Luminal pH and bile salts were determined in duodenal aspirates. Procedures were also performed in PPI-refractory patients with FD ("FD-stoppers") before and 8 weeks after PPI withdrawal. Between- and within-group changes from baseline and associations with duodenal or systemic factors were analyzed using linear mixed models.

RESULTS

The study was completed by 30 HV, 27 FD-starters, and 18 FD-stoppers. Symptoms and duodenal eosinophils, mast cells (all, P < .0001), and paracellular passage (P = .02) were significantly higher in FD-starters vs HVs and reduced with PPI therapy. Symptoms and duodenal immune cells also decreased in FD-stoppers off PPIs. In contrast, immune cells and permeability increased in HVs on PPIs. Dyspeptic symptoms correlated with eosinophils before and during PPI therapy, and increased eosinophils and permeability in HVs on PPIs were associated with changes in bile salts.

CONCLUSIONS

We provide the first prospective evidence for eosinophil-reducing effects as a therapeutic mechanism of PPIs in FD, with differential effects in HVs pointing to a role of luminal changes. ClinicalTrials.gov, Number: NCT03545243.

Infant acid suppression use is associated with the development of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is an esophageal allergic inflammatory disorder often presenting with infant/toddler gastroesophageal reflux symptoms refractory to treatment, including acid suppression trials with histamine H2 antagonists and proton pump inhibitors. We propose to evaluate the impact of infant acid suppressant exposure in EoE. Geisinger's pediatric EoE cases were matched to controls (1:5 EoE case control ratio) using age, race, sex, and ages at other diagnoses of asthma, eczema, and environmental allergies, totaling 526 EoE cases and 2,630 controls. Comparisons between EoE cases and matched controls were tested with regard to rates of acid suppression use with H2 antagonists and PPIs during infancy. Our analyses found the use of acid suppression in infancy was positively associated with EoE: PPI (5.7% EoE cases vs. 1.6% controls; P < 0.0001), H2 antagonists (8.8% EoE cases vs. 4.5% controls; P < 0.0001). Additionally, analysis of EoE cases using acid suppression during infancy indicated a likelihood for the diagnosis with EoE at an earlier age. Early acid suppression use in infants is significantly associated with the diagnosis of EoE in childhood in this well-matched retrospective cohort study. The potential link warrants additional investigation. Our study further reinforces the evidence-based stewardship of acid suppressant use, especially in our most vulnerable populations.

Proton pump inhibitors enhance intestinal permeability via dysbiosis of gut microbiota under stressed conditions in mice

BACKGROUND

Intestinal permeability and psychological stress are considered the key mechanism(s) in functional dyspepsia (FD). Although proton pump inhibitors (PPIs) are commonly used for the treatment of FD, the effect of PPIs on intestinal permeability has not been elucidated. This study investigated the effect of PPI on intestinal permeability under stressed conditions.

METHODS

C57BL/6J mice were subjected to water avoidance stress (WAS) and administered rabeprazole (40 mg/kg) or vehicle treatment (VT). We then evaluated intestinal permeability both in vivo and ex vivo using plasma fluorescein isothiocyanate-dextran and by assessing the paracellular permeability and transepithelial electrical resistance (TEER) in an Ussing chamber, respectively. Furthermore, we evaluated the effect of PPI-treated fecal microbiota transplant (FMT) on intestinal permeability in vivo. Microbiota profiles of donor feces were assessed by 16S rRNA gene analysis using MiSeq and QIIME2.

KEY RESULTS

In the WAS treatment, PPI significantly enhanced intestinal permeability in vivo compared to that in VT. Moreover, PPI significantly increased paracellular permeability and decreased TEER in the duodenum and jejunum, respectively, compared to those in VT under stressed conditions. Moreover, both vasoactive intestinal peptide (VIP) receptor antagonist and ketotifen significantly reversed the effect of PPI on intestinal permeability. Furthermore, PPI-treated FMT significantly increased the intestinal permeability in vivo compared to that in vehicle-treated FMT. Proton pump inhibitors treatment altered the gut microbiota composition, indicating that PPI induced dysbiosis.

CONCLUSIONS AND INFERENCES

Under stressed conditions, PPI enhances intestinal permeability via dysbiosis of gut microbiota. Vasoactive intestinal peptide and mast cells are also implicated in the underlying mechanisms.

Impact of Gastroesophageal Reflux Disease on Mucosal Immunity and Atopic Disorders

Atopic disorders and gastroesophageal reflux disease (GERD) are some of the most common medical conditions treated by primary care physicians and specialists alike. The observation that atopic disorders, like asthma, allergic rhinitis and sinusitis, food allergies, atopic dermatitis, contact dermatitis, and eosinophilic esophagitis are common comorbidities in patients with GERD raises the question of the nature of the relationship that may exist between GERD and atopic disorders. In this article, we review the pathophysiology of GERD, its effect on the immune system, the effect of acid-blocking medications on allergic responses, as well as several common atopic conditions that have been associated with GERD including asthma, chronic rhinosinusitis (CRS), allergic rhinitis (AR), atopic dermatitis (AD), contact dermatitis (CD), food allergies, proton pump inhibitor (PPI)-responsive esophageal eosinophilia (PPI-REE), and eosinophilic esophagitis (EoE). In each condition, the evidence of a causal link is not definitive. Although the relationship between asthma and GERD remains controversial, evidence suggests that a subset of asthma patients with documented GERD may experience improved asthma control following appropriate treatment of GERD. The relationship of GERD to allergic rhinitis and chronic sinusitis is weak; however, studies support the concept that treatment of frequent episodes of GERD can have a positive effect on rhinitis and sinusitis overall. The relationship between allergic sensitization and GERD is likely bidirectional. GERD may induce changes in the mucosal immune system that may favor the development of food allergy and allergic sensitization to aeroallergens; however, the underlying mechanisms have not been established.

Early Life Risk Factors in Pediatric EoE: Could We Prevent This Modern Disease?

Eosinophilic esophagitis (EoE) is a chronic antigen-mediated inflammatory disease that affects the esophagus. In the last 20 years, a large number of epidemiological studies showed a significant increase in the incidence and prevalence of EoE, especially in developed countries. This phenomenon might correlate to the overall increase in pediatric allergic diseases or might be a result of improved medical awareness and knowledge through modern diagnostic instruments. Since 1993, when EoE was first recognized as a distinct clinical entity, several signs of progress in the pathophysiology of EoE were achieved. However, a few studies reported data on early risk factors for pediatric EoE and how these factors may interfere with genes. Currently, the most defined risk factors for EoE are male sex, Caucasian race, and atopic comorbidities. Other putative risk factors may include alterations in epithelial barrier function and fibrous remodeling, esophageal dysbiosis, variation in the nature and timing of oral antigen exposure, and early prescription of proton pump inhibitors and antibiotics. Notably, the timing and nature of food antigen exposure may be fundamental in inducing or reversing immune tolerance, but no studies are reported. This review summarized the current evidence on the risk factors that might contribute to the increasing development of EoE, focusing on the possible preventive role of early interventions.

Food Allergies and Ageing

All over the world, there is an increase in the overall survival of the population and the number of elderly people. The incidence of allergic reactions is also rising worldwide. Until recently, allergies, and in particular food allergies (FAs), was regarded as a pediatric problem, since some of them start in early childhood and may spontaneously disappear in adulthood. It is being discovered that, on the contrary, these problems are increasingly affecting even the elderly. Along with other diseases that are considered characteristics of advanced age, such as cardiovascular, dysmetabolic, autoimmune, neurodegenerative, and oncological diseases, even FAs are increasingly frequent in the elderly. An FA is a pleiomorphic and multifactorial disease, characterized by an abnormal immune response and an impaired gut barrier function. The elderly exhibit distinct FA phenotypes, and diagnosis is difficult due to frequent co-morbidities and uncertainty in the interpretation of in vitro and in vivo tests. Several factors render the elderly susceptible to FAs, including the physiological changes of aging, a decline in gut barrier function, the skewing of adaptive immunity to a Th2 response, dysregulation of innate immune cells, and age-related changes of gut microbiota. Aging is accompanied by a progressive remodeling of immune system functions, leading to an increased pro-inflammatory status where type 1 cytokines are quantitatively dominant. However, serum Immunoglobulin E (IgE) levels and T helper type 2 (Th2 cytokine production have also been found to be increased in the elderly, suggesting that the type 2 cytokine pattern is not necessarily defective in older age. Dysfunctional dendritic cells in the gut, defects in secretory IgA, and decreased T regulatory function in the elderly also play important roles in FA development. We address herein the main immunologic aspects of aging according to the presence of FAs.

Acute haemodynamic changes during haemodialysis do not exacerbate gut hyperpermeability

INTRODUCTION

The gastrointestinal tract is a potential source of inflammation in dialysis patients. In vitro studies suggest breakdown of the gut barrier in uraemia leading to increased intestinal permeability and it is hypothesised that haemodialysis exacerbates this problem due to mesenteric ischaemia induced by blood volume changes during treatment.

METHOD

The effect of haemodialysis on intestinal permeability was studied in ten haemodialysis patients and compared with five controls. Intestinal permeability was assessed by measuring the differential absorption of four orally administered sugar probes which provides an index of small and whole bowel permeability. A multi-sugar solution (containing lactulose, rhamnose, sucralose and erythritol) was orally administered after an overnight fast. Plasma levels of all sugar probes were measured hourly for 10 h post-administration. In haemodialysis patients, the procedure was carried out twice - once on a non-dialysis day and once immediately after haemodialysis.

RESULTS

Area under curve (AUC) for lactulose:rhamnose (L:R) ratio and sucralose:erythritol (S:E) ratio was similar post-dialysis and on non-dialysis days. AUC for L:R was higher in haemodialysis patients compared with controls (0.071 vs. 0.034, P=0.001), AUC for S:E ratio was not significantly different. Levels of lactulose, sucralose and erythritol were elevated and retained longer in haemodialysis patients compared with controls due to dependence of sugars on kidney function for clearance.

CONCLUSION

We found no significant acute changes in intestinal permeability in relation to the haemodialysis procedure. Valid comparison of intestinal permeability between controls and haemodialysis patients was not possible due to the strong influence of kidney function on sugar levels.

Eosinophilic esophagitis: novel concepts regarding pathogenesis and clinical manifestations

This report explores two hypotheses regarding eosinophilic esophagitis (EoE): (1) that the use of proton pump inhibitors (PPIs) might contribute to the pathogenesis of EoE by preventing peptic digestion of food allergens, by increasing gastric mucosal permeability to enable gastric absorption of those undegraded food allergens, and by causing microbial dysbiosis, and (2) that EoE, like eosinophilic gastroenteritis, might have mucosal-predominant and muscle-predominant forms, and that the muscle-predominant form of EoE might cause a variety of esophageal motility disorders including achalasia.

Gastroesophageal reflux disease, functional dyspepsia and irritable bowel syndrome: common overlapping gastrointestinal disorders

Several studies have indicated an overlap between gastroesophageal reflux disease (GERD) and various functional gastrointestinal disorders (FGIDs). The overlapping conditions reported have mainly been functional dyspepsia (FD) and irritable bowel syndrome (IBS). The available literature is frequently based on symptomatic questionnaires or endoscopic procedures to diagnose GERD. Rarely, among patients with heartburn, pathophysiological evaluations have been considered to differentiate those with proven GERD from those without. Moreover, both GERD and IBS or FD showed enormous heterogeneity in terms of the criteria and diagnostic procedures used. The GERD-IBS overlap ranges from 3-79% in questionnaire-based studies and from 10-74% when GERD has been diagnosed endoscopically. The prevalence of functional dyspepsia (after normal upper endoscopy) is 12-15% and an overlap with GERD has been reported frequently. Only a few studies have considered a potential overlap between functional heartburn (FH) and IBS using a 24-h pH-metry or impedance-pH evaluation. Similar data has been reported for an overlap between FH and FD. Recently, a revision of the Rome criteria for esophageal FGIDs identified both FH and hypersensitive esophagus (HE) as potential functional esophageal disorders. This might increase the potential overlap between different FGIDs, with FH and HE rather than with GERD. The aim of the present review article was to appraise and discuss the current evidence supporting the possible concomitance of GERD with IBS and FD in the same patients and to evaluate how various GERD treatments could impact on the quality of life of these patients.

Environmental factors and eosinophilic esophagitis

The incidence and prevalence of eosinophilic esophagitis (EoE) have markedly increased over the past 2 decades, outpacing increased detection of the disease. Although genetic susceptibility markers for EoE have begun to be elucidated, the rate at which EoE has increased in incidence suggests environmental factors predominate. Despite many advances in understanding of the pathogenesis of EoE, the cause of EoE is unknown. This article reviews the emerging data related to environmental risk factors for EoE. Many of these environmental factors are rooted in the theoretical framework of the hygiene hypothesis, specifically mediation of disease development through dysbiosis. Other hypotheses are based on associations that have been observed in studies of non-EoE allergic disease. We describe the evidence that early-life exposures, including antibiotic use, acid suppression, and cesarean delivery, can increase the risk of disease. We also describe the evidence that infectious agents, such as Helicobacter pylori, are inversely associated with disease. Current evidence on geographic risk factors, such as population density, climate zone, and seasonality, is reviewed. We also describe behavioral factors that have been evaluated. Limitations of the existing research are discussed, and recommendations for future areas of research, including assessment of gene-environment interaction, are presented.

Speculation as to why the Frequency of Eosinophilic Esophagitis Is Increasing

PURPOSE OF REVIEW

The frequency of eosinophilic esophagitis (EoE), an immune/antigen-mediated disorder first described in 1993, has been increasing rapidly. The purpose of this review is to consider hypotheses proposed to explain this increase and to speculate on their validity.

RECENT FINDINGS

The hygiene hypothesis attributes the rise of EoE to modern hygienic conditions resulting in fewer childhood infections with microbes that might have protected against allergy development. Microbial dysbiosis, a change in the microbiome's composition and diversity caused by a modern affluent lifestyle, also might contribute to allergic conditions. Environmental factors including modern chemicals contaminating crops, livestock treated with hormones and antibiotics, food additives and processing changes, and pollutants in the air and water conceivably might predispose to EoE. One intriguing hypothesis attributes increasing EoE to increasing use of acid-suppressive medications like proton pump inhibitors, which might prevent peptic digestion of food allergens, increase gastric permeability, and alter the microbiome to favor food allergy development. In a recent pediatric case-control study, use of acid suppressants in infancy was by far the single strongest risk factor identified for later development of EoE. It remains unclear which, if any, of the above factors underlies the rising frequency of EoE. These factors need not be mutually exclusive, and the cause of EoE may well be multifactorial.

Speculation as to why the Frequency of Eosinophilic Esophagitis Is Increasing

PURPOSE OF REVIEW

The frequency of eosinophilic esophagitis (EoE), an immune/antigen-mediated disorder first described in 1993, has been increasing rapidly. The purpose of this review is to consider hypotheses proposed to explain this increase and to speculate on their validity.

RECENT FINDINGS

The hygiene hypothesis attributes the rise of EoE to modern hygienic conditions resulting in fewer childhood infections with microbes that might have protected against allergy development. Microbial dysbiosis, a change in the microbiome's composition and diversity caused by a modern affluent lifestyle, also might contribute to allergic conditions. Environmental factors including modern chemicals contaminating crops, livestock treated with hormones and antibiotics, food additives and processing changes, and pollutants in the air and water conceivably might predispose to EoE. One intriguing hypothesis attributes increasing EoE to increasing use of acid-suppressive medications like proton pump inhibitors, which might prevent peptic digestion of food allergens, increase gastric permeability, and alter the microbiome to favor food allergy development. In a recent pediatric case-control study, use of acid suppressants in infancy was by far the single strongest risk factor identified for later development of EoE. It remains unclear which, if any, of the above factors underlies the rising frequency of EoE. These factors need not be mutually exclusive, and the cause of EoE may well be multifactorial.

Helicobacter pylori infection and occurrence of celiac disease in subjects HLA-DQ2/DQ8 positive: A prospective study

BACKGROUND

Celiac disease (CD) occurs in subjects positive for HLA-DQ2 and/or DQ8 gene loci at any age following ingestion of gluten-containing food. An increased permeability of the mucosa allows interactions between gliadin macromolecules and genetic factors. It has been observed that Helicobacter pylori has the ability to modulate the integrity of the duodenal epithelium. We aimed to determine whether H. pylori infection may enhance the occurrence of CD in genetically susceptible subjects.

MATERIALS AND METHODS

This was a prospective observational study. Patients undergoing upper endoscopy for any reason and positive for HLA-DQ2 and/or DQ8 haplotypes with or without CD were included. H. pylori infection was defined as a positive gastric histopathology and/or 13C-urea breath test. Prevalence of infection was compared between enrolled subjects with and without CD. Multiple logistic regression analysis, adjusting odds ratios for patient age, gender, smoking habit, residency, body mass index, and assumption of nonsteroidal anti-inflammatory drugs (NSAIDs) and proton-pump inhibitors (PPIs) were performed.

RESULTS

A total of 397 genetically susceptible individuals (mean age: 37.7 ± 15.3 years; 86% women) were enrolled between October 2014 and October 2017. There were 265 (68%) patients with a diagnosis of CD. Overall, the prevalence of H. pylori infection was 33% and was similar in patients with and without CD (32% vs 36%). Adjustment for all covariates did not reveal any significant association, although adjusted odds ratio (OR) for CD was higher in female (OR = 1.302), in patients H. pylori positive (OR = 1.277), followed by use of NSAIDs (OR = 1.126), respectively. The use of PPIs appeared to be mildly protective against CD (OR = 0.644).

CONCLUSION

Our study did not reveal any significant relationship between H. pylori and CD risk, even taking into account other confounders. More importantly, our findings do not support a "protective" role of H. pylori infection against CD, as previously reported. Therefore, there are no reasons to avoid eradication of H. pylori also in subject genetically susceptible for CD.

Acid-Suppressive Therapy and Risk of Infections: Pros and Cons

This narrative review summarises the benefits, risks and appropriate use of acid-suppressing drugs (ASDs), proton pump inhibitors and histamine-2 receptor antagonists, advocating a rationale balanced and individualised approach aimed to minimise any serious adverse consequences. It focuses on current controversies on the potential of ASDs to contribute to infections-bacterial, parasitic, fungal, protozoan and viral, particularly in the elderly, comprehensively and critically discusses the growing body of observational literature linking ASD use to a variety of enteric, respiratory, skin and systemic infectious diseases and complications (Clostridium difficile diarrhoea, pneumonia, spontaneous bacterial peritonitis, septicaemia and other). The proposed pathogenic mechanisms of ASD-associated infections (related and unrelated to the inhibition of gastric acid secretion, alterations of the gut microbiome and immunity), and drug-drug interactions are also described. Both probiotics use and correcting vitamin D status may have a significant protective effect decreasing the incidence of ASD-associated infections, especially in the elderly. Despite the limitations of the existing data, the importance of individualised therapy and caution in long-term ASD use considering the balance of benefits and potential harms, factors that may predispose to and actions that may prevent/attenuate adverse effects is evident. A six-step practical algorithm for ASD therapy based on the best available evidence is presented.

Eosinophilic esophagitis. The North against the South? A bio-economic-social mechanistic approach and clinical implications

Eosinophilic esophagitis is a chronic antigen-mediated disease characterized by esophageal symptoms, esophageal eosinophilia, and the absence of response to proton pump inhibitors. It is the most frequent cause of dysphagia and food impaction in adults. Its incidence and prevalence is very high in the developed countries (USA, Europe, Australia), where its connotation is that of an emerging epidemic. While studies have been published with large case series in the developed countries, those published in Latin America are small or consist of isolated case reports. The differences in the prevalence of the disease between the developed and developing regions are unknown. Genetic or racial causes have been cited. Nevertheless, the epidemic nature of the disease suggests that environmental causes are the most powerful. Based on the published hypotheses, as well as on epidemiologic studies, the present review discusses some of the possible causes of the disparity in the prevalence of eosinophilic esophagitis between the two types of countries. The 'hygiene hypothesis' is reviewed, together with the possible relation of Helicobacter pylori, intestinal parasites, and modifications of the esophageal microbiota in patients with eosinophilic esophagitis. In reference to studies conducted in the United States, the clinical behavior and progression of eosinophilic esophagitis in Hispanics is reviewed and a possible predominant phenotype in Mexican and other Latin American patients is discussed. Finally, based on the above, an algorithm for studying the disease in the Latin American countries is proposed.

The intestinal barrier: a fundamental role in health and disease

The gastrointestinal mucosa constitutes a critical barrier where millions of microbes and environmental antigens come in close contact with the host immune system. Intestinal barrier defects have been associated with a broad range of diseases and therefore denote a new therapeutic target. Areas covered: This review is based on an extensive literature search in PubMed of how the intestinal barrier contributes to health and as a trigger for disease. It discusses the anatomy of the intestinal barrier and explains the available methods to evaluate its function. Also reviewed is the importance of diet and lifestyle factors on intestinal barrier function, and three prototypes of chronic diseases (inflammatory bowel disease, celiac disease and nonalcoholic fatty liver disease) that have been linked to barrier defects are discussed. Expert commentary: The intestinal barrier has been investigated by various methods, but correlation of results across studies is difficult, representing a major shortcoming in the field. New upcoming techniques and research on the effect of barrier-restoring therapeutics may improve our current understanding of the gut barrier, and provide a step forward towards personalised medicine.

The impact of acid suppression medications and non-steroidal anti-inflammatory drugs on clinical and histologic features in celiac disease

INTRODUCTION

The prevalence of celiac disease (CD) in the US has increased in past decades, as has use of proton pump inhibitors (PPIs), histamine-2-receptor antagonists (H2RAs), aspirin (ASA) and nonsteroidal anti-inflammatory drugs (NSAIDs). We aimed to measure the association between medication use and distribution of villous flattening (VF) among newly diagnosed CD patients.

METHODS

We performed a cross-sectional study of adult patients with newly-diagnosed CD at two institutions. We collected data on regular use of these medications, clinical presentation, CD serologic status, and distribution of VF. We compared current ASA/NSAID users to non-users, and current PPI/H2RA users to non-users, with regard to these clinical characteristics.

RESULTS

Of 148 patients with newly-diagnosed CD, current users of ASA/NSAIDs were older than non-users (47 vs 39 years, p=0.003) and users of PPI/H2RAs were older than non-users (48 vs 39 years, p=0.004). PPI/H2RA users comprised 12% of seropositive patients, compared to 55% of seronegative patients (p<0.01). Patient gender and distribution of villous flattening in the bulb and distal duodenum did not differ by PPI/H2RA or ASA/NSAID use.

CONCLUSIONS

PPI/H2RA use was associated with seronegative CD. Given the effect of these medications on gastric milieu, the impact of these drugs on presentation and course of CD deserves further investigation.

Drug Exposure and the Risk of Microscopic Colitis: A Critical Update

A variety of luminal antigens, including a wide range of drugs, have been associated with the still little-known pathophysiology of microscopic colitis (MC), with variable evidence suggesting causality. This article aims to review the aspects related to drugs as potential triggers of MC; to discuss the most commonly identified associations between drugs and MC; and to analyze the limitations of the studies currently available. A literature search was performed in PubMed combining the search terms 'drug exposure', 'drug consumption', and 'risk factors' with 'microscopic colitis', 'lymphocytic colitis', and 'collagenous colitis', with no language restrictions. Reference lists of retrieved documents were also reviewed. A handful of case-control studies have demonstrated significant associations between some commonly used drugs and a higher risk of developing MC. No universally accepted criteria for establishing cause-effect relationships in adverse reactions to drugs are available, but several methods that can be applied to MC, can provide degrees of the likelihood of an association. A high probability imputation in the development of MC as a drug adverse effect has only been demonstrated for individual cases by applying chronological (challenge, de-challenge, and relapse with re-challenge) and semiological criteria. Several case-control studies have shown significant associations between exposure to drugs and MC, but the variability in their design, the reference populations used, and the definitions for drug exposure considered require specific analyses. It can be concluded that drug exposure and MC as a likely cause-effect relationship has only been described for a handful of drugs and in individual cases.

The efficacy of human placenta-derived mesenchymal stem cells on radiation enteropathy along with proteomic biomarkers predicting a favorable response

BACKGROUND

Radiation enteropathy is a common complication in patients with abdominopelvic cancer, but no treatment has yet been established. Stem cell therapy may be a viable therapeutic option because intestinal stem cells are highly vulnerable to ionizing radiation (IR) and stem cell loss explains its intractability to general treatment. Here, we investigated either prophylactic or therapeutic efficacy of human placenta-derived mesenchymal stem cells (hPDSCs) against radiation enteropathy and could identify biomarkers predicting a favorable response to stem cell therapy.

METHODS

We challenged a radiation-induced enteropathy model with hPDSCs. After sacrifice, we checked the gross anatomy of small intestine, histology gross, and analyzed that, accompanied with molecular changes implicated in this model.

RESULTS

hPDSCs significantly improved the outcome of mice induced with either radiation enteropathy or lethal radiation syndrome (P < 0.01). hPDSCs exerted inhibitory actions on inflammatory cytokines, the re-establishment of epithelium homeostasis was completed with increasing endogenous restorative processes as assessed with increased levels of proliferative markers in the hPDSCs group, and a significant inhibition of IR-induced apoptosis. The preservation of cells expressing lysozyme, and Musashi-1 were significantly increased in the hPDSC treatment group. Both preventive and therapeutic efficacies of hPDSCs were noted against IR-induced enteropathy. Label-free quantification was used to identify biomarkers which predict favorable responses after hPDSC treatment, and finally glutathione S-transferase-mu type, interleukin-10, and peroxiredoxin-2 were validated as proteomic biomarkers predicting a favorable response to hPDSCs in radiation enteropathy.

CONCLUSIONS

hPDSCs may be a useful prophylactic and therapeutic cell therapy for radiation enteropathy.

Endoscopy-Guided Evaluation of Duodenal Mucosal Permeability in Functional Dyspepsia

Objectives:

The pathophysiology of functional dyspepsia (FD) is not fully understood. Impaired duodenal mucosal integrity characterized by increased mucosal permeability and/or low-grade inflammation was reported as potentially important etiologies. We aimed to determine the utility of a recently developed simple catheterization method to measure mucosal admittance (MA), the inverse of mucosal impedance, for evaluation of duodenal mucosal permeability in patients with FD.

Methods:

We conducted two prospective studies. In the first study, duodenal MA of 23 subjects was determined by catheterization during upper endoscopy, and transepithelial electrical resistance (TEER) of duodenal biopsy samples in Ussing chambers was measured to assess the correlation between MA and TEER. In the second study, duodenal MA of 21 patients with FD fulfilling the Rome III criteria was compared with that of 23 healthy subjects.

Results:

The mean MA and TEER values were 367.5±134.7 and 24.5±3.7 Ω cm², respectively. There was a significant negative correlation between MA and TEER (r=−0.67, P=0.0004, Pearson's correlation coefficient). The mean MA in patients with FD was significantly higher than that in healthy subjects (455.7±137.3 vs. 352.1±66.9, P=0.002, unpaired t-test). No procedure-related complications were present.

Conclusions:

We demonstrated the presence of increased duodenal mucosal permeability in patients with FD by MA measurement using a simple catheterization method during upper endoscopy.

Factors associated with villus atrophy in symptomatic coeliac disease patients on a gluten-free diet

BACKGROUND

Duodenal injury persists in some coeliac disease patients despite gluten-free diet, and is associated with adverse outcomes.

AIM

To determine the prevalence and clinical risk factors for persistent villus atrophy among symptomatic coeliac disease patients.

METHODS

A nested cross-sectional analysis was performed on coeliac disease patients with self-reported moderate or severe symptoms while following a gluten-free diet, who underwent protocol-mandated duodenal biopsy upon enrolment in the CeliAction clinical trial. Demographic factors, symptom type, medication use, and serology were examined to determine predictors of persistent villus atrophy.

RESULTS

Of 1345 symptomatic patients, 511 (38%, 95% CI, 35-41%) were found to have active coeliac disease with persistent villus atrophy, defined as average villus height to crypt depth ratio ≤2.0. On multivariable analysis, older age (OR, 5.1 for ≥70 vs. 18-29 years, 95% CI, 2.5-10.4) was a risk factor while longer duration on gluten-free diet was protective (OR, 0.37, 95% CI, 0.24-0.55 for 4-5.9 vs. 1-1.9 years). Villus atrophy was associated with use of proton-pump inhibitors (PPIs; OR, 1.6, 95% CI, 1.1-2.3), non-steroidal anti-inflammatory drugs (NSAIDs; OR, 1.64, 95% CI, 1.2-2.2), and selective serotonin reuptake inhibitors (SSRIs; OR, 1.74, 95% CI, 1.2-2.5). Symptoms were not associated with villus atrophy after adjusting for covariates. Conclusions A majority of symptomatic coeliac disease patients did not have active disease on follow-up histology. Symptoms were poorly predictive of persistent mucosal injury. The impact of NSAIDs, PPIs, and SSRIs on mucosal healing in coeliac disease warrants further study.

Genetic ablation or pharmacologic inhibition of autophagy mitigated NSAID-associated gastric damages

Non-steroidal anti-inflammatory drug (NSAID)-associated endoplasmic reticulum (ER) stress (a cyclooxygenase-2-independent mechanism) and consequent autophagic cell death are responsible for NSAID-associated gastric damage. Therefore, alleviating cytotoxicity executed via ER stress and autophagy can be a strategy to prevent NSAID-associated gastric damage. Here, we explored whether genetic or pharmacologic inhibition of autophagy can mitigate NSAID-associated gastric damage in in vitro and in vivo models. To examine the effects of genetic inhibition of NSAID-associated autophagy, we administered indomethacin to RGM1 gastric mucosal cells transfected with shPERK, siLC3B, or shATG5 and microtubule-associated protein light chain 3B knock-out (LC3B^-/-) mice. 3-Methyladenine (3-MA) or chloroquine (CQ) was used for pharmacologic inhibition of autophagy in both models. Indomethacin administration increased the expression of ER stress proteins including GRP78, ATF6, and CHOP. Indomethacin provoked the appearance of autophagic vesicles with the increased expression of ATG5 and LC3B-II. Genetic ablation of various ER stress genes significantly attenuated indomethacin-induced autophagy and apoptosis (p < 0.01), whereas knock-down of either ATG5 or LC3B significantly reduced indomethacin-induced cytotoxicity (p < 0.01). Testing each of the genes implicated in ER stress and autophagy showed that indomethacin leads to gastric cell apoptosis through autophagy induction consequent to ER stress. Pharmacological inhibition of autophagy with either 3-MA or CQ in rats or genetic ablation of LC3B in mice all had a significant rescuing effect against indomethacin-associated gastric damage (p < 0.01) and a decrease in molecular markers of autophagic and apoptotic gastric cells. In conclusion, preemptive autophagy inhibition can be a potential strategy to mitigate NSAID-associated gastric damage.

KEY MESSAGES

NSAID administration triggered ER stress and subsequent autophagy. Inhibition of autophagy resulted in attenuated NSAID-associated cytotoxicity. Autophagy inhibitors represent a novel strategy to prevent NSAID-associated gastric damage.

Human Intestinal Barrier Function in Health and Disease

The gastrointestinal tract consists of an enormous surface area that is optimized to efficiently absorb nutrients, water, and electrolytes from food. At the same time, it needs to provide a tight barrier against the ingress of harmful substances, and protect against a reaction to omnipresent harmless compounds. A dysfunctional intestinal barrier is associated with various diseases and disorders. In this review, the role of intestinal permeability in common disorders such as infections with intestinal pathogens, inflammatory bowel disease, irritable bowel syndrome, obesity, celiac disease, non-celiac gluten sensitivity, and food allergies will be discussed. In addition, the effect of the frequently prescribed drugs proton pump inhibitors and non-steroidal anti-inflammatory drugs on intestinal permeability, as well as commonly used methods to assess barrier function will be reviewed.

Association Between Proton Pump Inhibitors and Microscopic Colitis

Objective: Microscopic colitis (MC) is a chronic inflammatory disease of the colon that is characterized by chronic, watery, nonbloody diarrhea. Concern regarding a potential association between proton-pump inhibitors (PPIs) and MC has recently emerged. We sought to systematically review and summarize the evidence for the potential association between PPIs and MC. Data Sources: We systematically searched EMBASE, MEDLINE, Cochrane Database of Systematic Reviews, International Pharmaceutical Abstracts, and Google Scholar using the terms proton-pump inhibitors (omeprazole, lansoprazole, dexlansoprazole, rabeprazole, pantoprazole, or esomeprazole), microscopic colitis, collagenous colitis, and lymphocytic colitis. Study Selection: Full-text, English-language reports of case reports/series, observational studies, experimental studies, and systematic reviews/meta-analyses published between January 2000 to August 2016 were included. Bibliographies from pertinent publications were reviewed for additional references. Outcome was defined as the development of biopsy-confirmed MC. Data Extraction/Synthesis: A total of 19 publications were identified: 5 case control studies and 14 case reports/series (encompassing a total of 32 cases). All studies were limited by small sample sizes. Risk of MC by dose or specific PPI agent was not investigated in any of the studies. A review of the current body of evidence reveals a possible association between PPIs and MC. Conclusions: There is a need for large observational studies of high quality to examine the differential effect of specific PPIs and whether the magnitude of association is dose dependent. Given their widespread use, clinicians should routinely question whether patients are receiving unnecessary treatment with PPIs and discontinue therapy where appropriate.

An Overview of the Diagnosis and Management of Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic inflammatory condition characterized by symptoms of esophageal dysfunction and eosinophilic infiltration of the esophageal mucosa. The diagnosis requires esophageal biopsies demonstrating at least 15 eosinophils per high-powered field following a course of high-dose proton pump inhibitors. Management of EoE consists of the three Ds: drugs, dietary therapy, and esophageal dilation. In this review, we discuss the epidemiology, pathogenesis, diagnosis, and treatment of EoE to include the role of emerging therapies.

Acid suppression therapy and allergic reactions

The development of pharmaceutical agents such as sucralfate, histamine 2 (H2) receptor blockers and proton pump inhibitors (PPIs) reducing gastric acidity has been a mile stone for treatment of dyspeptic disorders. However, due to current prescription habits resulting in overuse of these potent drugs as well as over-the-counter (OTC) availability associated with self-medication, substantial health concern is related to the mechanisms of drug action as well as known side effects influencing gastrointestinal physiology. More than a decade ago the first study appeared reporting an association between anti-ulcer drug intake and food allergy development. Ever since this first report several experimental as well as human studies verified this correlation, demonstrating that acid suppressive drugs not only influence the sensitization capacity of orally ingested proteins, but also represent a risk factor for food allergy patients. Additionally, gastric acid suppression was reported to increase the risk for development of drug hypersensitivity reactions. These consequences of anti-ulcer drug intake might on the one hand be associated with direct influence of these drugs on immune responses. On the other hand reduction of gastric acidity leads to impaired gastrointestinal protein degradation. Nevertheless, also disruption of the gastrointestinal barrier function, changes in microbiome or lack of tolerogenic peptic digests might contribute to the connection between anti-ulcer drug intake and allergic reaction. Therefore, these drugs should only be prescribed based on a precise gastroenterological diagnosis taking into consideration allergological mechanisms to ensure patients' safety.

Environmental and infectious factors in eosinophilic esophagitis

Identifying possible environmental or infectious etiologic factors for eosinophilic esophagitis (EoE) may offer insight into opportunities for disease prevention and treatment. We reviewed the current literature to assess environmental and infectious factors evaluated in EoE. Few studies have been conducted, however a consistent inverse association between EoE and H. pylori has been described. Several studies suggest a weak association between season and EoE diagnosis, but the evidence is inconclusive. EoE has also been associated with early life factors, including Cesarean delivery and antibiotic use. Larger studies are needed to evaluate these associations more thoroughly. Several papers have speculated the potential for anti-secretory agents to contribute to EoE. This has not been formerly evaluated. In summary, there is significant opportunity in the future to advance our understanding of possible environmental etiologic factors for EoE.

Clinical predictors associated with proton pump inhibitor-induced hypomagnesemia

There is increasing evidence and case reports regarding proton pump inhibitor (PPI)-induced hypomagnesemia. Our study aimed to clarify the relationship between PPI use and serum magnesium levels and to specify high-risk patients. We retrospectively studied 112 consecutive patients aged 20 years or older who were treated with PPI for ≥30 days and whose serum magnesium levels were available for the PPI treatment period. We compared the mean level of serum magnesium of the enrolled patients with PPI treatment with matched controls. There were no significant differences between the matched PPI users (n = 105) and nonusers (n = 210) in the magnesium levels (0.85 ± 0.09 vs. 0.86 ± 0.16 mM, P = 0.297). In a subgroup analysis of a PPI user group, hypomagnesemia could be observed in 32 patients but not in 80 patients. In multivariate analyses, PPI use for >1 year, age less than 45 years, and concurrent cisplatin or carboplatin use were significantly associated with PPI-induced hypomagnesemia {P = 0.042, odds ratio [OR; 95% confidence interval (CI)]: 5.388 [1.056-27.493]; P = 0.007, OR [95% CI]: 4.710 [1.523-14.571]; P = 0.007, OR [95% CI]: 13.404 [2.066-86.952], respectively} after adjusting for confounders. This study shows that long-term PPI use is associated with hypomagnesemia in hospitalized adult patients. Therefore, serum magnesium levels should be checked before the initiation of PPI treatment and during the treatment period in patients, particularly those concurrently using platinum-based chemotherapy or who are expected to use PPI for long periods.

Urinary Sugars--A Biomarker of Total Sugars Intake

Measurement error in self-reported sugars intake may explain the lack of consistency in the epidemiologic evidence on the association between sugars and disease risk. This review describes the development and applications of a biomarker of sugars intake, informs its future use and recommends directions for future research. Recently, 24 h urinary sucrose and fructose were suggested as a predictive biomarker for total sugars intake, based on findings from three highly controlled feeding studies conducted in the United Kingdom. From this work, a calibration equation for the biomarker that provides an unbiased measure of sugars intake was generated that has since been used in two US-based studies with free-living individuals to assess measurement error in dietary self-reports and to develop regression calibration equations that could be used in future diet-disease analyses. Further applications of the biomarker include its use as a surrogate measure of intake in diet-disease association studies. Although this biomarker has great potential and exhibits favorable characteristics, available data come from a few controlled studies with limited sample sizes conducted in the UK. Larger feeding studies conducted in different populations are needed to further explore biomarker characteristics and stability of its biases, compare its performance, and generate a unique, or population-specific biomarker calibration equations to be applied in future studies. A validated sugars biomarker is critical for informed interpretation of sugars-disease association studies.

Risk of spontaneous bacterial peritonitis associated with gastric Acid suppression

The primary objective of this study was to determine the association between the use of gastric acid suppressants (GAS) and the risk of developing spontaneous bacterial peritonitis (SBP) in patients with advanced liver cirrhosis (LC). A case-control study nested within a cohort of 480,000 representatives of Taiwan National Health Insurance beneficiaries was carried out. A case was matched with 100 controls on age, gender, and index date of SBP diagnosis. GAS use was identified from the 1-year period before the index date. Conditional logistic regression analysis was used to adjust for various unbalanced covariates between users and nonusers of GAS. A total of 947 cases of SBP were identified among the 86,418 patients with advanced LC. A significant increased risk of developing SBP was found to be associated with current (within 30 days), and recent (within 30-90 day) use of 2 different classes of GAS: proton pump inhibitors (PPIs) and histamine 2 receptor antagonists (H2RAs). The confounder adjusted rate ratio (aRR) for the current use of PPIs was 2.77 (95% CI: 1.90-4.04) and H2RAs was 2.62 (95% CI: 2.00-3.42). The risk of SBP attenuated for the recent use of PPIs (aRR: 2.20, 95%CI: 1.60-3.02) or H2RAs (aRR: 1.72, 95% CI: 1.25-2.37). In addition, sensitivity analysis using hospitalized SBP as the primary outcome showed a similar risk for the current use of PPIs (aRR, 3.24; 95% CI: 2.08-5.05) and H2RAs (aRR 2.43; 95% CI 1.71-3.46). Furthermore, higher cumulative days of gastric acid suppression were associated with a higher risk of SBP (trend P < 0.0001). To conclude, exposure to GAS was associated with an increased risk of SBP in patients with advanced LC. The association was more pronounced in current PPI users compared with nonusers.

Increased risk of microscopic colitis with use of proton pump inhibitors and non-steroidal anti-inflammatory drugs

OBJECTIVES

Microscopic colitis (MC) is characterized by chronic watery diarrhea. Recently, several drugs were reported to increase the risk of MC. However, studies lacked a clear exposure definition, did not address duration relationships, and did not take important biases into account. We estimated the risk of MC during drug use.

METHODS

This is a population-based nested case-control study using a Dutch primary care database (1999-2013). Incident MC cases (aged ≥18 years) were matched to community-based and colonoscopy-negative controls on age, sex, and primary care practice. Drug use was assessed within 1 and 2 years before the index date. Adjusted odds ratios (OR) were calculated by conditional logistic regression.

RESULTS

From the source population of 1,458,410 subjects, 218 cases were matched to 15,045 community controls and 475 colonoscopy-negative controls. Current use (≤3 months) of proton pump inhibitors (PPIs), nonsteroidal anti-inflammatory drugs (NSAIDs), selective serotonin reuptake inhibitors, low-dose aspirin, angiotensin-converting enzyme (ACE) inhibitors and beta-blockers significantly increased the risk of MC compared with never use in community controls. Adjusted ORs ranged from 2.5 (95% confidence interval (CI): 1.5-4.2) for ACE inhibitors to 7.3 (95% CI: 4.5-12.1) for PPIs in the year prior to the index date. After accounting for diagnostic delay, only use of NSAIDs, PPIs, low-dose aspirin, and ACE inhibitors increased the risk of MC. Compared with colonoscopy controls, only use of PPIs (OR-adjusted 10.6; 1.8-64.2) and NSAIDs (OR-adjusted 5.6; 1.2-27.0) increased the risk of MC.

CONCLUSIONS

NSAIDs and PPIs are associated with an increased risk of MC. The association of MC with use of the other drugs is probably explained by worsening of diarrhea/symptoms rather than increasing the risk of MC itself.

Association between recent use of proton pump inhibitors and nontyphoid salmonellosis: a nested case-control study

BACKGROUND

The association between proton pump inhibitors (PPIs) and nontyphoid salmonellosis (NTS) continues to be debated. The current study was designed to determine the association between use of oral PPIs and the diagnosis of NTS.

METHODS

The Taiwan National Health Insurance Research Database from 2000 to 2010 was searched for cases of NTS, defined by the International Classification of Disease, Ninth revision, Clinical Modification. A nested case-control study in hospitalized population was conducted using 4 controls for each case patient (14 736 case patients and 58 944 controls), matched for age, month and year of entry, Charlson comorbidity index score, and well-known predisposing factors for NTS, including autoimmune diseases, acquired immunodeficiency syndrome, diabetes, cirrhosis, transplantation, gastrointestinal operations or diseases, and malignancies.

RESULTS

Persons with NTS had a higher rate of using oral PPIs within the prior year (adjusted odds ratio [OR], 2.09; 95% confidence interval [CI], 1.95-2.24; P < .001). The association was greatest for current PPI use (adjusted OR, 5.39; 95% CI, 4.79-6.06; P < .001). Although use of H2-receptor antagonists (adjusted OR, 1.84; 95% CI, 1.71-1.98), antibiotics (5.21; 4.81-5.64), steroids (3.18; 2.99-3.39), and nonsteroidal anti-inflammatory drugs (2.37; 2.26-2.48) within the 30 days were also associated with NTS, the linkage between PPI use and NTS remained significant in the subgroup without these medications.

CONCLUSIONS

The use of oral PPIs was associated with the occurrence of NTS. The risk waned with time after discontinuation.

Small intestinal permeability is increased in diarrhoea predominant IBS, while alterations in gastroduodenal permeability in all IBS subtypes are largely attributable to confounders

BACKGROUND

Intestinal permeability has been studied in small groups of IBS patients with contrasting findings.

AIMS

To assess intestinal permeability at different sites of the GI tract in different subtypes of well-characterised IBS patients and healthy controls (HC), and to assess potential confounding factors.

METHODS

IBS patients and HC underwent a multi-sugar test to assess site-specific intestinal permeability. Sucrose excretion and lactulose/rhamnose ratio in 0-5 h urine indicated gastroduodenal and small intestinal permeability, respectively. Sucralose/erythritol ratio in 0-24 h and 5-24 h urine indicated whole gut and colonic permeability, respectively. Linear regression analysis was used to assess the association between IBS groups and intestinal permeability and to adjust for age, sex, BMI, anxiety or depression, smoking, alcohol intake and use of medication.

RESULTS

Ninety-one IBS patients, i.e. 37% IBS-D, 23% IBS-C, 33% IBS-M and 7% IBS-U and 94 HC were enrolled. Urinary sucrose excretion was significantly increased in the total IBS group [μmol, median (Q1;Q3): 5.26 (1.82;11.03) vs. 2.44 (0.91;5.85), P < 0.05], as well as in IBS-C and IBS-D vs. HC. However, differences attenuated when adjusting for confounders. The lactulose/rhamnose ratio was increased in IBS-D vs. HC [0.023 (0.013;0.038) vs. 0.014 (0.008;0.025), P < 0.05], which remained significant after adjustment for confounders. No difference was found in 0-24 and 5-24 h sucralose/erythritol ratio between groups.

CONCLUSIONS

Small intestinal permeability is increased in patients with IBS-D compared to healthy controls, irrespective of confounding factors. Adjustment for confounders is necessary when studying intestinal permeability, especially in a heterogeneous disorder such as IBS.

Eosinophilic esophagitis: interactions with gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) and eosinophilic esophagitis (EoE) are not mutually exclusive. The notion that GERD and EoE can be distinguished by the response to proton pump inhibitor (PPI) treatment is based on the mistaken assumption that gastric acid suppression is the only important therapeutic effect of PPIs, and therefore only GERD can respond to PPIs. We believe that a clinical or histologic response to PPIs does not rule in GERD or rule out EoE. We recommend a trial of PPI therapy for patients with symptomatic esophageal eosinophilia, even if the diagnosis of EoE seems clear-cut.