Inflammation and oxidative stress in gastroesophageal reflux disease

Gastroesophageal reflux disease and risk for arrhythmias: a Mendelian randomization analysis

Background

Clinical observations and epidemiological studies suggest a potential linkage between gastroesophageal reflux disease (GERD) and arrhythmias, yet the underlying mechanism remains elusive. This study investigates the causal relationship between GERD and four types of arrhythmia through a genetic lens, employing Mendelian randomization analysis to elucidate the directionality of these associations.

Methods

Selected single nucleotide polymorphisms (SNPs) from genome-wide association study (GWAS) data were utilized as instrumental variables. The inverse variance weighting (IVW) method, MR-Egger regression analysis, and the weighted median method were employed in two-sample Mendelian randomization analysis. Horizontal pleiotropy was detected and corrected using the MR-PRESSO test and MR-Egger regression. The stability and reliability of the Mendelian randomization results were assessed using the leave-one-out method, Cochran's Q test, and funnel plots. The causal relationship between GERD and four types of arrhythmias was evaluated using the odds ratio (OR).

Results

IVW results indicated that GERD could increase the risk of arrhythmias. A one standard deviation increases in the logarithmically transformed GERD score resulted in a 34% increase in the risk of arrhythmia (OR = 1.34; 95% CI 1.19-1.51; p = 1.66E-06). No significant correlation was found between GERD and other arrhythmias.

Conclusion

A causal relationship exists between GERD and arrhythmias, suggesting that GERD increases the risk of developing these arrhythmias.

The oral microbiome and oral and upper gastrointestinal diseases

Background

Microbiomes are essential components of the human body, and their populations are substantial. Under normal circumstances, microbiomes coexist harmoniously with the human body, but disturbances in this equilibrium can lead to various diseases. The oral microbiome is involved in the occurrence and development of many oral and gastrointestinal diseases. This review focuses on the relationship between oral microbiomes and oral and upper gastrointestinal diseases, and therapeutic strategies aiming to provide valuable insights for clinical prevention and treatment.

Methods

To identify relevant studies, we conducted searches in PubMed, Google Scholar, and Web of Science using keywords such as "oral microbiome," "oral flora, " "gastrointestinal disease, " without any date restrictions. Subsequently, the retrieved publications were subject to a narrative review.

Results

In this review, we found that oral microbiomes are closely related to oral and gastrointestinal diseases such as periodontitis, dental caries, reflux esophagitis, gastritis, and upper gastrointestinal tumors (mainly the malignant ones). Oral samples like saliva and buccal mucosa are not only easy to collect, but also display superior sample stability compared to gastrointestinal tissues. Consequently, analysis of the oral microbiome could potentially serve as an efficient preliminary screening method for high-risk groups before undergoing endoscopic examination. Besides, treatments based on the oral microbiomes could aid early diagnosis and treatment of these diseases.

Conclusions

Oral microbiomes are essential to oral and gastrointestinal diseases. Therapies centered on the oral microbiomes could facilitate the early detection and management of these conditions.

The relationship between oxidative balance scores and chronic diarrhea and constipation: a population-based study

BACKGROUND

Oxidative stress is closely related to gut health. Exposures to oxidative stress in one's diet and lifestyle can be evaluated by the oxidative balance score (OBS). However, the relationship between OBS and intestinal habits is unknown. This study aimed to investigate the relationships between OBS and intestinal habits (chronic diarrhea and chronic constipation) and the underlying mechanisms involved.

METHODS

Using data from the National Health and Nutrition Examination Survey (NHANES) database from 2005 to 2010, we included a total of 8065 participants. Twenty dietary and lifestyle factors were selected for the OBS calculates. Chronic constipation and chronic diarrhea were defined using the Bristol stool form scale (BSFS) types 1 and 2 and the BSFS 6 and 7, respectively. Multivariate logistic regression, subgroup analysis, and restricted cubic splines (RCS) analysis were used to evaluate the relationship between OBS and defecation habits. Finally, we used mediation analysis to explore the indirect effects of oxidative stress and inflammatory markers on these associations.

RESULTS

After adjusting for all the covariates, multivariate logistic regression analysis revealed that OBS was negatively correlated with diarrhea (OR = 0.57; 95%CI = 0.39-0.83; P = 0.008)and positively correlated with constipation (OR = 1.75; 95%CI = 1.19-2.25; P = 0.008). The RCS showed a nonlinear relationship between OBS and diarrhea (P for nonlinearity = 0.02) and a linear relationship between OBS and constipation (P for nonlinearity = 0.19). Mediation analysis showed that the C-reactive protein (CRP) concentration and white blood cell (WBC) count mediated the correlation between OBS and diarrhea by 6.28% and 6.53%, respectively (P < 0.05).

CONCLUSIONS

OBS is closely related to changes in patients' defecation habits. Oxidative stress and inflammation may play a role in the relationship between the two. This result emphasizes the importance of the public adjusting their lifestyle and dietary habits according to their own situation. However, further prospective studies are needed to analyze the relationship between oxidative stress and changes in defecation habits.

Mucosal neuroimmune mechanisms in gastro-oesophageal reflux disease (GORD) pathogenesis

Gastro-oesophageal reflux disease (GORD) is a chronic condition characterised by visceral pain in the distal oesophagus. The current first-line treatment for GORD is proton pump inhibitors (PPIs), however, PPIs are ineffective in a large cohort of patients and long-term use may have adverse effects. Emerging evidence suggests that nerve fibre number and location are likely to play interrelated roles in nociception in the oesophagus of GORD patients. Simultaneously, alterations in cells of the oesophageal mucosa, namely epithelial cells, mast cells, dendritic cells, and T lymphocytes, have been a focus of GORD research for several years. The oesophagus of GORD patients exhibits both macro- and micro-inflammation as a response to chronic acidic reflux at the epithelium. In other conditions of the GI tract, such as IBS and IBD, well-characterised bidirectional processes between immune cells and mucosal nerve fibres contribute to pathogenesis and symptom generation. Sensory alterations in these conditions such as nerve fibre outgrowth and hypersensitivity can be driven by inflammatory processes, which promote visceral pain signalling. This review will examine what is currently known of the molecular pathways linking inflammation and sensory perception leading to the development of GORD symptoms and explore potentially relevant mechanisms in other GI regions which may indicate new areas in GORD research.

Efficacy of an oral suspension containing xyloglucan and pea proteins on a murine model of gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is the most common foregut disease, affecting about 20% of the adult population. Esophageal epithelial barrier plays a fundamental role in the pathophysiology of GERD; however, pharmacological therapies mainly aim to reduce the acidity of the gastroesophageal environment rather than to protect esophageal tissue integrity. This study aims to evaluate the efficacy of an oral solution containing xyloglucan and pea proteins (XP) in reestablishing gastroesophageal tissue integrity and biochemical markers. To induce GERD, C57BL/6 mice were alternatively overfed and fasted for 56 days and then treated with XP, sodium alginate, omeprazole, or omeprazole+XP twice daily for 7 days. Gastric pain and inflammatory markers were evaluated after 3 and 7 days of treatment. After sacrifice, the esophagi and stomachs were surgically removed for macroscopic and histological examination. Gastric pain was significantly reduced at days 3 and 7 by XP, omeprazole, and omeprazole+XP, while alginates were ineffective at day 3. XP was able to diminish gastric macroscopic damage and demonstrated the same efficacy as omeprazole in reducing esophageal damage. XP significantly reduced histological damage, with an efficacy comparable to that of omeprazole, but superior to alginates. Inflammatory markers were significantly reduced by XP, with superior efficacy compared with alginates at day 7. Interestingly, XP was also able to significantly increase gastric pH. This study demonstrated that XP restored gastric homeostasis, improved esophageal integrity, and decreased inflammation and pain with a similar efficacy to omeprazole and greater than alginates.

Low Antioxidant Enzyme Levels and Oxidative Stress in Laryngopharyngeal Reflux (LPR) Patients

OBJECTIVE

Laryngopharyngeal reflux disease (LPR) is a characterized by symptoms different from gastroesophageal reflux disease (GERD). LPR can causes chronic mucosal inflammation which may lead to an increase in cytokine production, and a systemic decrease in antioxidant enzyme levels. Our aim in this study is to evaluate antioxidant enzyme levels in patients with LPR.

METHODS

Reflux Symptom Index (RSI) questionnaire, extraesophageal symptom questionnaire which is included in RSI and Reflux Finding Score (RFS) evaluation with 70° rigid laryngoscope were performed to patients who applied to the otolaryngology clinic with a typical LPR complaint, and 60 patients who had an RSI score above 13 and an RFS score above 7 were included in the study. Thirty people consisting of healthy volunteers were included in the control group. Antioxidant enzyme SOD, GSH-Px and CAT levels were measured in the blood serum of the patients and compared with the control group. Results obtained from biochemical tests were expressed as mean ± SE. Descriptive statistical methods (mean ± standard error) were used for the independent t test for the control and study group. P < 0.05 was considered statistically significant.

RESULTS

In the LPR group, 28 (46%) were women, 32 (53%) were men, and age range was 21-60, average age was 36.45 ± 1.147.There was no significant difference between LPR and control group in terms of age, gender and Body Mass Index (BMI). In the LPR group, the lowest score for RSI was 14 and the highest score was 39. The average RSI was 23.67. RFS ranges from 8-22. The mean RFS was 13.50. A highly significant statistical correlation was observed between RSI and total RFS (P < 0.001). There was a significant difference between the antioxidant enzyme levels of the control group and the LPR group. Antioxidant enzyme levels of the control group were SOD 274.10 ± 26.836 U / L, GSH-Px 174.20 ± 20.699 µU / mL and CAT 42.2898 ± 20.699 KU / L. Antioxidant enzyme level results of the LPR group were SOD 147 ± 14.022 U / L (P < 0.01), GSH-Px 88.28 ± 9.113 µU / mL (P < 0.01) and CAT 12.67 ± 0.799 KU / L (P < 0.001). The RSI results ranges from 4 to 39 and the RFS from 8 to 22. Antioxidant enzyme levels demonstrated fairly consistent reliability with individual variables from both RFS and RFS. There was also a highly significant statistical correlation between RSI and RFS.

CONCLUSION

We found that the antioxidant enzymes SOD, GPX and catalase enzyme levels were significantly lower in LPR patients. Treatment modalities to reduce oxidative stress (OS) in LPR should be investigated.

TRPV1 is a risk factor for sleep disturbance in patients with gastro-oesophageal reflux disease: a case control study

BACKGROUND/AIMS

Gastro-oesophageal reflux disease (GORD) is a chronic high-morbidity disease with a bidirectional relationship with sleep disturbance (SD) that may occur via the transient receptor potential vanilloid type 1 receptor (TRPV1) in the oesophageal mucosa. Yet the related mechanism was still unclear, the aim of this study is to investigate whether TRPV1 is associated with the presence of SD in GORD patients.

METHODS

A case-control study was performed. After the screening, A total of 88 subjects were assigned to GORD without sleep disturbance (GORD + NOSD, n = 28), GORD comorbid sleep disturbance (GORD + SD, n = 30) and matched healthy controls (n = 30). Mucosal tissue was obtained from the participants by digestive endoscopy, the levels of TRPV1 expressed in the oesophageal mucosa were detected via RT-qPCR and western blot in different groups, and the correlation between GORD and SD were also analysed.

RESULTS

In this study, we found that the Gastroesophageal Reflux Disease Diagnostic Questionnaire (GerdQ) scores was positively correlated with Pittsburgh Sleep Quality Index (PSQI) scores but negatively correlated with total sleep time (TST). We also found that the level of TRPV1 expressed in the oesophageal mucosa of GORD + SD was significantly higher than GORD + NOSD patients, and they were all higher than healthy controls.

CONCLUSION

The current study suggested a closer link exists between GORD and sleep disturbance, and TRPV1 in oesophageal mucosa may be a crucial factor affecting sleep in GORD patients.

The Relationship between Gastroesophageal Reflux Disease and Chronic Kidney Disease

Gastroesophageal reflux disease (GERD) is commonly seen in patients with chronic kidney disease (CKD), although data on the relationship between these conditions are still limited. We aimed to explore whether CKD is related to a higher prevalence of GERD and its complications. National Inpatient Sample data were used in this retrospective analysis, including 7,159,694 patients. Patients who had a diagnosis of GERD with and without CKD were compared with patients without GERD. Complications associated with GERD that were analyzed included Barrett's esophagus and esophageal stricture. Risk factors of GERD were used for variable adjustment analysis. Different stages of CKD were evaluated in patients with and without GERD. Bivariate analyses were performed using the chi-squared test or Fisher exact test (2-tailed) for categorical variables as appropriate to assess the difference. There were significantly different demographic characteristics between GERD patients with and without CKD regarding age, sex, race, and other co-mobilities. Interestingly, a greater prevalence of GERD was seen in CKD patients (23.5%) compared to non-CKD patients (14.8%), and this increased prevalence was consistently seen in all CKD stages. CKD patients also had 1.70 higher odds of risk of having GERD compared with non-CKD after adjustment. The association between different stages of CKD and GERD showed a similar trend. Interestingly, patients with early-stage CKD were found to have a higher prevalence and odds of risk of esophageal stricture and Barrett's esophagus than non-CKD patients. CKD is associated with a high prevalence of GERD and its complications.

Risk of Periodontitis in Patients with Gastroesophageal Reflux Disease: A Nationwide Retrospective Cohort Study

Background: Gastroesophageal reflux disease (GERD) is the most common digestive clinical problem worldwide that affects approximately 20% of the adult populations in Western countries. Poor oral hygiene has been reported to be associated with GERD as an atypical clinical complication. However, evidence showing the relationship between GERD and the risk of periodontitis is less clear. The present study aimed to use a retrospective cohort study design to further clarify the association between GERD and the subsequent risk of periodontitis. Methods: The risk of periodontitis in patients with GERD was investigated by analyzing epidemiological data from the Taiwan National Health Insurance Research Database from 2008 to 2018. We selected 20,125 participants with a minimum age of 40 years in the GERD group and 1:1 propensity-matched these with non-GERD individuals by sex, age, and comorbidities. The incidence of periodontitis was determined at the end of 2018. A Cox proportional hazards regression model was used to evaluate the risk of periodontitis in patients with GERD. Results: The overall incidence rate of the periodontitis risk was 1.38-fold higher (30.0 vs. 21.7/1000 person years, adjusted hazard ratio (aHR) = 1.36, 95% confidence interval (CI) = 1.28−1.45) in patients with GERD than in those without GERD. After stratified analyses for sex, age, and comorbidity, patients with GERD had a higher risk of periodontitis for age (aHR = 1.31, 95% CI = 1.20−1.42 for 40−54 years and aHR = 1.42, 95% CI =1.28−1.57 for 55−69 years), sex (aHR = 1.40, 95% CI = 1.28−1.54 for men and aHR = 1.33, 95% CI = 1.23−1.45 for women), and presence (aHR = 1.36, 95% CI = 1.27−1.45) and absence (aHR = 1.40, 95% CI = 1.21−1.62) of comorbidity than those without GERD. Among the GERD cohort, the risk for periodontitis was increased with an increasing number of emergency room visits (≥ 1 vs. <1, aHR = 5.19, 95% CI = 2.16−12.5). Conclusions: Our results revealed that patients with GERD have a higher risk of periodontitis development than those without GERD. Clinicians should pay more attention to identifying and managing periodontitis in patients with GERD.

Objectively confirmed gastroesophageal reflux disease and risk of atrial fibrillation: a population-based cohort study in Sweden

OBJECTIVE

This study aimed to determine the risk of atrial fibrillation in patients with objectively confirmed GERD.

METHODS

This was a nationwide population-based cohort study between 2005 and 2018, including the majority ( n = 8 421 115) of all Swedish adult residents (≥18 years). Within this cohort, the exposed group were all individuals with a diagnosis of esophagitis or Barrett's esophagus, and the unexposed group was made up of five times as many individuals without any GERD, matched by age, sex, and calendar year. The outcome was the first diagnosis of atrial fibrillation. Cox regression provided hazard ratios (HRs) with 95% confidence intervals (CIs), adjusted for confounders.

RESULTS

Among 118 013 individuals with esophagitis or Barrett's esophagus and 590 065 without GERD, 7042 (6.0%) and 40 962 (6.9%) developed atrial fibrillation, respectively. The risk of atrial fibrillation among patients with GERD was 13% increased within the first year of diagnosis (HR, 1.13; 95% CI, 1.06-1.20), but was not increased after that. Among individuals aged less than 60 years, the HR of atrial fibrillation was 55% increased within the first year of diagnosis (HR, 1.55; 95% CI, 1.27-1.88), and this association remained increased after the first year (HR, 1.14; 95% CI, 1.06-1.22). No association was found in older participants (≥60 years). Results were similar in men and women.

CONCLUSION

This large population-based cohort study indicates that objectively determined GERD increases the risk of atrial fibrillation shortly after diagnosis in men and women younger than 60 years.

NF-κB: A novel therapeutic pathway for gastroesophageal reflux disease?

Although gastroesophageal reflux disease (GERD), a common chronic disease in clinical practice, has been widely studied, its potential adverse impact on patients is still a significant clinical concern. It is necessary to understand the pathogenesis of the disease and choose appropriate treatment according to its mechanism. The pathogenesis of GERD is diverse and complex. As the traditional treatment methods are expensive and ineffective in alleviating symptoms in some patients, new treatment options need to be explored. Our previous study suggested that the activation of nuclear factor-kappa beta (NF-κB) in esophageal mucosa may be related to the injury of epithelial barrier function caused by reflux. Based on the literature and our previous study results, it is speculated that inhibition of NF-κB activation may block the insult of GERD on the esophageal mucosal barrier. NF-κB may play an important role in the development of GERD. This article reviews the pathogenesis of GERD and the relationship between NF-κB and GERD, in order to provide new strategies for the treatment of GERD.

Molecular Mechanism of the Effect of Zhizhu Pill on Gastroesophageal Reflux Disease Based on Network Pharmacology and Molecular Docking

Background

To investigate the pharmacological mechanism of Zhizhu pill (ZZP) against gastroesophageal reflux disease (GERD), network pharmacology in combination with molecular docking was applied in this study.

Methods

Active compounds of ZZP and target genes related to GERD were identified through public databases. Subsequently, the obtained data were used as a basis for further network pharmacological analysis to explore the potential key active compounds, core targets, and biological processes involved in ZZP against GERD. Finally, the results predicted by network pharmacology were validated by molecular docking.

Results

Twenty active components of ZZP were identified to act on 59 targets related to GERD. Enrichment analysis revealed that multiple biological processes including response to oxygen levels, response to oxidative stress, and response to reactive oxygen species were involved in the GERD ZZP treatment with ZZP. ZZP had an impact on the prognosis of GERD mainly through the HIF-1 signaling pathway, PI3K-Akt signaling pathway, and pathways in cancer. Further analysis identified the key components and core targets of ZZP against GERD, of which nobiletin, didymin, luteolin, and naringenin were key components, and PPARG, MMP9, JUN, TP53, PTGS2, EGFR, MAPK3, CASP3, AKT1, and VEGFA were the core targets. Molecular docking verified the stable bonds formed between the key components and the core targets.

Conclusions

The results of this study predict that the therapeutic effects of ZZP in GERD are mediated at least in part via PPARG, MMP9, JUN, TP53, PTGS2, EGFR, MAPK3, CASP3, AKT1, and VEGFA. These results may be useful in providing an experimental basis and new ideas for further research on ZZP in GERD.

Effectiveness of Nutritional Ingredients on Upper Gastrointestinal Conditions and Symptoms: A Narrative Review

Nutritional ingredients, including various fibers, herbs, and botanicals, have been historically used for various ailments. Their enduring appeal is predicated on the desire both for more natural approaches to health and to mitigate potential side effects of more mainstream treatments. Their use in individuals experiencing upper gastrointestinal (GI) complaints is of particular interest in the scientific space as well as the consumer market but requires review to better understand their potential effectiveness. The aim of this paper is to review the published scientific literature on nutritional ingredients for the management of upper GI complaints. We selected nutritional ingredients on the basis of mentions within the published literature and familiarity with recurrent components of consumer products currently marketed. A predefined literature search was conducted in Embase, Medline, Derwent drug file, ToXfile, and PubMed databases with specific nutritional ingredients and search terms related to upper GI health along with a manual search for each ingredient. Of our literature search, 16 human clinical studies including nine ingredients met our inclusion criteria and were assessed in this review. Products of interest within these studies subsumed the categories of botanicals, including fiber and combinations, and non-botanical extracts. Although there are a few ingredients with robust scientific evidence, such as ginger and a combination of peppermint and caraway oil, there are others, such as melatonin and marine alginate, with moderate evidence, and still others with limited scientific substantiation, such as galactomannan, fenugreek, and zinc-l-carnosine. Importantly, the paucity of high-quality data for the majority of the ingredients analyzed herein suggests ample opportunity for further study. In particular, trials with appropriate controls examining dose-response using standardized extracts and testing for specific benefits would yield precise and effective data to aid those with upper GI symptoms and conditions.

Pathophysiology of Pediatric Gastroesophageal Reflux Disease: Similarities and Differences With Adults

Gastroesophageal reflux (GOR) is defined as "the passage of gastric contents into the esophagus with or without regurgitation and vomiting" and gastroesophageal reflux disease (GORD) is defined "when GOR leads to troublesome symptoms affecting the daily functioning and/or complications." This definition was first developed in 2006 by the Montreal consensus group (1) and later on adopted by pediatric gastroenterology societies such as ESPGHAN and NASPGHAN in 2009 (2). The definition of gastroesophageal reflux reveals little about its pathophysiology and is focused on symptomatology. In this way, it acts as an umbrella term for the multifactorial causes of the disease and the various phenotypes encountered; from functional heartburn to hypersensitive esophagus and nonerosive reflux disease, to erosive esophagitis and Barrett's esophagus. This article is devoted to the pathophysiology of pediatric GORD in comparison to adult GORD and is divided in 2 parts. In the first part, we will systematically describe the different mechanisms for the generation and clearance of reflux events, while on the second part we will discuss the mechanisms involved in symptoms generation. Finally, we will discuss the similarities and differences between pediatric and adult GORD.

Nitric oxide and inducible nitric oxide synthase levels in EE and NERD patients

Aim

This article aimed to evaluate nitric oxide (NO) and nitric oxide synthase (iNOS) markers in patients with erosive esophagitis (EE) and those with non-erosive reflux disease (NERD) and compare them with the control group.

Background

Gastro-esophageal reflux disease (GERD) is one of the most common disturbances of the upper digestive tract. Inducible nitric oxide synthase (iNOS) is expressed in esophageal adenocarcinoma. NO, the product of this enzyme, has been implicated in the pathogenesis of this condition. Nevertheless, the data on whether iNOS and NO are expressed in the early stages of GERD is conflicting.

Methods

In this study, tissue samples were obtained from fifty-four patients (27 with erosive esophagitis and 27 with non-erosive reflux disease) and 27 controls. Tissue concentrations of nitrite, nitrate, and iNOS were measured using Enzyme-Linked Immune-sorbent Assay (ELISA). The Bradford method was used to determine the protein concentration of samples. The results were analyzed by SPSS software (version 22.0). In multiple comparisons, the Tukey test was performed, and p < 0.05 was considered as the level of significance.

Results

Tissue amounts of iNOS were significantly higher (p= 0.001) in EE patients compared with the control group. There was a significant difference (p= 0.01) in this factor between EE patients and patients with NERD. Moreover, tissue levels of nitrite and nitrate were significantly higher (p = 0.001) in patient groups compared with the control group.

Conclusion

It was observed that NO and iNOS protein were increased in human esophagitis tissue. The results indicated that nitric oxide and iNOS levels are useful and effective markers in the pathogenesis of GERD. While the results are not certain, it is thought that a link exists between the expressions of iNOS and disease progression.

IκB Kinase-β Regulates Neutrophil Recruitment Through Activation of STAT3 Signaling in the Esophagus

BACKGROUND & AIMS

The epithelial barrier is the host's first line of defense against damage to the underlying tissue. Upon injury, the epithelium plays a critical role in inflammation. The IκB kinase β (IKKβ)/nuclear factor-κB pathway was shown to be active in the esophageal epithelium of patients with esophageal disease. However, the complex mechanisms by which IKKβ signaling regulates esophageal disease pathogenesis remain unknown. Our prior work has shown that expression of a constitutively active form of IKKβ specifically in esophageal epithelia of mice (Ikkβca^{Esophageal Epithelial Cell-Knockin (EEC-KI)}) is sufficient to cause esophagitis.

METHODS

We generated ED-L2/Cre;Rosa26-Ikkβca^+/L;Stat3^L/L (Ikkβca^EEC-KI;Stat3^{Esophageal Epithelial Cell Knockout (EEC-KO)}) mice, in which the ED-L2 promoter activates Cre recombinase in the esophageal epithelium, leading to constitutive activation of IKKβ and loss of Stat3. Esophageal epithelial tissues were collected and analyzed by immunostaining, RNA sequencing, quantitative real-time polymerase chain reaction assays, flow cytometry, and Western blot. Ikkβca^EEC-KI mice were treated with neutralizing antibodies against interleukin (IL)23p19 and IL12p40.

RESULTS

Here, we report that Ikkβca^EEC-KI mice have increased activation of epithelial Janus kinase 2/STAT3 signaling. Stat3 deletion in Ikkβca^EEC-KI mice attenuated the neutrophil infiltration observed in Ikkβca^EEC-KI mice and resulted in decreased expression of genes related to immune cell recruitment and activity. Blocking experiments in Ikkβca^EEC-KI mice showed that STAT3 activation and subsequent neutrophil recruitment are dependent on IL23 secretion.

CONCLUSIONS

Our study establishes a novel interplay between IKKβ and STAT3 signaling in epithelial cells of the esophagus, where IKKβ/IL23/STAT3 signaling controls neutrophil recruitment during the onset of inflammation. GEO accession number: GSE154129.

Global burden and epidemiology of Barrett oesophagus and oesophageal cancer

Oesophageal cancer is a global health problem; in 2018 there were more than 572,000 people newly diagnosed with oesophageal cancer worldwide. There are two main histological subtypes of oesophageal cancer, oesophageal adenocarcinoma (EAC) and oesophageal squamous cell carcinoma (ESCC), and there has been a dramatic shift in its epidemiology. While the incidence of EAC and its precursor lesion, Barrett oesophagus, has increased in Western populations over the past four decades, the incidence of ESCC has declined in most parts of the world over the same period. ESCC still accounts for the vast majority of all oesophageal cancer cases diagnosed worldwide each year. Prognosis for patients with oesophageal cancer is strongly related to stage at diagnosis. As most patients are diagnosed with late-stage disease, overall 5-year survival for oesophageal cancer remains <20%. Knowledge of epidemiology and risk factors for oesophageal cancer is essential for public health and clinical decisions about risk stratification, screening and prevention. The goal of this Review is to establish the current epidemiology of oesophageal cancer, with a particular focus on the Western world and the increasing incidence of EAC and Barrett oesophagus.

Do patients with gastroesophageal reflux disease exhibit compromised bone quality prior to proton pump inhibitor therapy?

Patients with gastroesophageal reflux disease (GERD) are routinely treated with proton pump inhibitors (PPIs), despite many reports of increased fracture risk associated with PPI use. Notably, the skeletal properties in patients with GERD prior to PPI therapy have not been addressed. We hypothesized that PPI-naïve GERD patients have bone impairment, and that short-term treatment with PPI has minimal skeletal effects. To test this, 17 (12 men/5 women) GERD patients age 32–73 years, not previously exposed to PPI, and 17 age- and sex-matched controls were enrolled from September 2010 to December 2012. Bone mineral density (BMD) at lumbar spine, femoral neck, total hip, and trabecular bone score (TBS) at the lumbar spine, a marker of bone microarchitecture, were measured by dual X-ray absorptiometry. Markers of bone turnover and calcium homeostasis, and gastric hormones were analyzed. The same parameters were measured after three months of treatment with the PPI pantoprazole. The GERD patients displayed a significantly lower TBS at baseline than controls (1.31 ± 0.11 vs. 1.43 ± 0.07, p = 0.0006). Total hip and femoral neck BMD were lower in patients compared to controls, however, not significantly (p = 0.09 and 0.12, respectively). CTX was non-significantly higher in GERD patients at baseline (p = 0.11). After three months, changes in BMD, TBS and CTX did not differ between the groups. In conclusion, this is the first report demonstrating compromised bone quality and inferior BMD in PPI-naïve GERD patients. Treatment with pantoprazole did not influence bone parameters, indicating that short-term use with this PPI is safe for the skeleton.

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Previous studies have reported an increased fracture risk in PPI users.

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Patients with GERD had compromised bone quality before starting PPI.

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Three months treatment with pantoprazole did not influence bone parameters.

Gene expression profiling of inflammatory cytokines in esophageal biopsies of different phenotypes of gastroesophageal reflux disease: a cross-sectional study

BACKGROUND

The clinical endoscopic phenotypes of gastroesophageal reflux disease (GERD) are classified as Barrett's esophagus (BE), erosive esophagitis (EE) and non-erosive gastroesophageal reflux disease (NERD). NERD is subclassified as abnormal acid exposure (AAE) and normal acid exposure (NAE) based on pH monitoring study results. The aim of this study was to characterize genes involved in the pathophysiology and immune response of GERD.

METHODS

This is an observational and cross-sectional study. All patients with BE, EE, AAE, and NAE and a control group were subjected to superior endoscopy (with biopsies of esophageal mucosa). Relative mRNA quantification of cytokine and target genes was conducted by quantitative Polymerase Chain Reaction (RT-qPCR). Changes in the expression of genes associated with inflammation were assessed for each disease phenotype. Statistical analysis of differential gene expression was performed using the Mann-Whitney U non-parametric test. A p value < 0.05 was considered significant.

RESULTS

A total of 82 patients were included and were divided into the following groups: Group BE, 16 (19.51%); Group EE, 23 (28.04%); Group AAE, 13 (15.86%); NAE 13 (15.86%); and Control Group, 17 (20.73%). Compared with the control group, patients with BE exhibited increased IL-8 expression (p < 0.05) and increased levels of IL-10, MMP-3, and MMP-9. Patients with EE exhibited increased levels of IL-1B, IL-6 and IL-10 (p < 0.05), and patients with AAE exhibited increased expression of IL-1B, IL-6, IFN-γ and TNF-α (p < 0.05). AAE exhibited increased IL-1B and TNF-α expression compared with NAE (p < 0.05).

CONCLUSION

This study demonstrates the differential expression of mediators of inflammation in the esophageal mucosa of patients with different GERD endoscopic phenotypes. IL-1B and TNF-α could be useful to differentially diagnose AAE and NAE in the non-erosive phenotype using endoscopic biopsies.

Non-surgical animal model of gastroesophageal reflux disease by overeating induced in mice

Previous animal models of gastroesophageal reflux disease (GERD) were not physiological and required a variety of surgical procedures. Therefore, the animal model developed by conditions that are similar to the pathogenesis of GERD is necessary. The aim is to establish a non-surgical animal model with GERD caused by overeating induced in mice. To induce mice to overeat, we designed dietary control protocols including repetitive fasting and feeding. The esophageal tissues were evaluated with GERD markers to prove the establishment of a GERD animal model. Mice fasted every other day (group 2) showed more pronounced overeating feature and demonstrated evident changes similar to the macroscopic and microscopic findings of GERD, the expressions of inducible nitric oxide synthase and substance P were stronger. The higher frequency of fasting and overeating could cause GERD effectively. The dietary control can make mice overeat, which elicits the change of lower esophageal mucosa similar to GERD. Thus, the overeating-induced mouse may be used as a GERD mouse model.

Mucosal pathogenesis in gastro-esophageal reflux disease

BACKGROUND

Despite gastro-esophageal reflux disease affecting up to 20% of Western populations, relatively little is known about the molecular mechanisms underlying its most troublesome symptom: heartburn. Recent findings have unveiled the role of components of the esophageal mucosa in the pathogenesis of GERD including sensory nociceptive nerves and inflammatory mediators. Erosive esophagitis was long believed to develop as a result of acid injury at the esophageal lumen, but novel concepts suggest the generation of reflux-induced esophageal injury as a result of cytokine-mediated inflammation. Moreover, the localization and characterization of mucosal afferent nerves vary between GERD phenotypes and could explain the heterogeneity of symptom perception between patients who experience similar levels of acid reflux.

PURPOSE

The purpose of this review is to consider the crosstalk of different factors of the esophageal mucosa in the pathogenesis of GERD, with a particular focus on mucosal innervation and molecular basis of acid-induced cytokine response. We discuss the current understanding of the mucosal response to acid injury, the nociceptive role of acid-sensitive receptors expressed in the esophageal mucosa, and the role of esophageal epithelial cells in initiating the onset of erosive esophagitis.

Protective and regenerative effects of a novel medical device against esophageal mucosal damage using in vitro and ex vivo models

Gastroesophageal reflux disease (GERD) is a common digestive disorder that causes esophagitis and injuries to the esophageal mucosa. GERD symptoms are recurrent during pregnancy and their treatment is focused on lifestyle changes and nonprescription medicines. The aim of this study was to characterize the mechanism of action of a new patented medical device, an oral formulation containing hyaluronic acid, rice extract, and amino acids dispersed in a bioadhesive polymer matrix, by assessing its protective effects in in vitro and ex vivo models of esophageal mucosa damage. Acidic bile salts and pepsin cocktail (BSC) added to CP-A and COLO-680 N esophagus cells were used as an in vitro GERD model to evaluate the binding capacities, anti-inflammatory effects and reparative properties of the investigational product (IP) in comparison to a viscous control. Our results showed that the IP prevents cell permeability and tight junction dysfunction induced by BSC. Furthermore, the IP was also able to down-regulate IL-6 and IL-8 mRNA expression induced by BSC stimulation and to promote tissue repair and wound healing. The results were confirmed by ex vivo experiments in excised rat esophagi through the quantification of Evans Blue permeability assay. These experiments provided evidence that the IP is able to bind to the human esophagus cells, preventing the damage caused by gastroesophageal reflux, showing potential anti-irritative, soothing, and reparative properties.

Gastroesophageal Reflux and Its Association With Atrial Fibrillation: A Traditional Review

Atrial fibrillation (AF) is a common arrhythmia, and gastroesophageal reflux disease (GERD) is a common gastroenterology disease; both are highly encountered daily in clinical practice. Since both share common predisposing factors, we can conclude that there is a link between them. To date, the precise mechanism of reflux disease as a possible cause of atrial fibrillation remains uncertain. However, some possibilities can be postulated, such as the inflammation process, and sympathovagal imbalance represents the main factors for how GERD can initiate AF. Vigorous aerobic exercise in healthy people can bring about acidic esophageal reflux, which is a common risk factor for AF. Various inflammatory markers such as C-reaction protein (CRP) and interleukins have been a central role in initiating AF. A large hiatal hernia (HH) can cause direct compression on the left atrium that is possibly predisposing to atrial arrhythmogenesis. It has been sporadically reported that using a proton pump inhibitor to treat GERD in patients with coexisting AF has a noticeable effect on decreasing symptoms of AF and recurrence with less cost and side effects.

Rebamipide using in gastroesophageal reflux disease treatment

Rebamipide is a mucoprotective drug which was developed in Japan in 1990. The therapeutic effect of rebamipide based on the induction of cyclooxygenase-2 and increasing level of prostaglandins, inhibition of oxygen free radicals production, epidermal growth factor stimulation, vascular endothelial growth factor, nitric oxide, and decreasing of lipid peroxidation and neutrophils migration. The combination of proton pump inhibitors and rebamipide is more effective in relieving of gastroesophageal reflux disease symptoms and reducing recurrence rate of disease. Using rebamipide in the treatment of gastroesophageal reflux disease is justified because this drug has a unique mechanism of action, which eliminating the main stages of pathogenesis of the disease.

Carbon Monoxide Being Hydrogen Sulfide and Nitric Oxide Molecular Sibling, as Endogenous and Exogenous Modulator of Oxidative Stress and Antioxidative Mechanisms in the Digestive System

Oxidative stress reflects an imbalance between oxidants and antioxidants in favor of the oxidants capable of evoking tissue damage. Like hydrogen sulfide (H₂S) and nitric oxide (NO), carbon monoxide (CO) is an endogenous gaseous mediator recently implicated in the physiology of the gastrointestinal (GI) tract. CO is produced in mammalian tissues as a byproduct of heme degradation catalyzed by the heme oxygenase (HO) enzymes. Among the three enzymatic isoforms, heme oxygenase-1 (HO-1) is induced under conditions of oxidative stress or tissue injury and plays a beneficial role in the mechanism of protection against inflammation, ischemia/reperfusion (I/R), and many other injuries. According to recently published data, increased endogenous CO production by inducible HO-1, its delivery by novel pharmacological CO-releasing agents, or even the direct inhalation of CO has been considered a promising alternative in future experimental and clinical therapies against various GI disorders. However, the exact mechanisms underlying behind these CO-mediated beneficial actions are not fully explained and experimental as well as clinical studies on the mechanism of CO-induced protection are awaited. For instance, in a variety of experimental models related to gastric mucosal damage, HO-1/CO pathway and CO-releasing agents seem to prevent gastric damage mainly by reduction of lipid peroxidation and/or increased level of enzymatic antioxidants, such as superoxide dismutase (SOD) or glutathione peroxidase (GPx). Many studies have also revealed that HO-1/CO can serve as a potential defensive pathway against oxidative stress observed in the liver and pancreas. Moreover, increased CO levels after treatment with CO donors have been reported to protect the gut against formation of acute GI lesions mainly by the regulation of reactive oxygen species (ROS) production and the antioxidative activity. In this review, we focused on the role of H₂S and NO molecular sibling, CO/HO pathway, and therapeutic potential of CO-releasing pharmacological tools in the regulation of oxidative stress-induced damage within the GI tract with a special emphasis on the esophagus, stomach, and intestines and also two solid and important metabolic abdominal organs, the liver and pancreas.

Improvement of Inflammation through Antioxidant Pathway of Gardeniae Fructus 50% EtOH Extract (GE) from Acute Reflux Esophagitis Rats

Gardeniae Fructus 50% EtOH extract (GE) is a traditional herb that has been used to treat a variety of diseases. In this study, we investigate the antioxidant, anti-inflammatory, and antiapoptotic properties of GE on acute reflux-induced esophagitis (RE) model in rats. 2,2′-Azino-bis (3-ethylbenzothiazolin-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays were performed to determine the antioxidant activity of GE. GE was given orally at 50 and 100 mg/kg body weight 1h 30 min prior to RE induction. And its effect was assessed in comparison with RE control and normal groups. The administration of the extract of the GE showed remarkable protection of mucosal damage in esophageal tissue, and the histologic observation showed that the gastric lesion was improved. Increased reactive oxygen species (ROS) levels in the serum were diminished by GE treatment. The antioxidative biomarkers including nuclear factor-erythroid 2-related factor 2 (Nrf-2), heme oxygenase-1 (HO-1), superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPX) were significantly increased. GE administration significantly reduced the inflammatory protein expression through MAPK-related signaling pathways and the nuclear factor-kappa B (NF-κB) pathway. These results suggest that GE protects the esophagus mucosal membrane by attenuating oxidative stress and inflammatory response under reflux esophagitis condition through the antioxidant pathway. Therefore, it is suggested that GE may be a potential remedy for the treatment of reflux esophagitis.

Effect of Acid Suppression on Peripheral T-Lymphocyte Subsets and Immunohistochemical Esophageal Mucosal Changes in Patients With Gastroesophageal Reflux Disease

BACKGROUND AND AIMS

Gastroesophageal reflux disease (GERD) is a common prevalent disease. We aimed to assess the dynamic changes in the peripheral T lymphocytes and lymphocytes infiltrating the esophageal mucosa after treatment with proton-pump inhibitor (PPI) in patients with GERD.

PATIENTS AND METHODS

A total of 200 patients who presented with upper GIT symptoms were included in this prospective study. All patients were subjected to full history taking, clinical examination, and complete blood count. Upper endoscopy was performed to detect the grade of GERD, followed by 4 quadrant biopsies before and 1 month after acid suppressive drug therapy. Histopathologic and immunohistochemical examination were carried out for all biopsies. Flow cytometry analysis for the peripheral T lymphocytes and cytokine profile assay before therapy and after therapy were also carried out.

RESULTS

In total, 200 patients comprising 132 male individuals (66%) and 68 female individuals (34%) with a mean age of 47.9±18.3 were included. The risk factors for development of GERD were smoking in 87 (43.5%), spicy food intake in 26 (13%), analgesics in 46 (23%), excessive tea and coffee in 35 (17.5%), and nondetected risk factors in 6 (3%). Endoscopic examination using Los Angeles grading system revealed that 102 patients (51%) were grade A, 57 patients (28.5%) were grade B, 38 patients (19%) were grade C, and 3 patients (1.5%) were grade D. No statistically significant differences could be detected in HGB levels and WBC, PLT, monocyte, granulocyte, and eosinophil counts before and after treatment with PPI. Histopathologic examination of esophageal biopsies showed significant posttreatment improvement in 132 cases (66%); however, 66 cases (33%) including the 2 cases (1%) of Barrett's esophagus showed nonsignificant pathologic improvement compared with the pretreatment picture. Immunohistochemical staining of esophageal biopsies with CD3 (T-cell marker) and CD20 (B-cell marker), before and 1 month after treatment, showed the presence of a very large number of infiltrating B cells in the esophageal mucosa (700±30/10 HPF) with large aggregations; in contrast, T-cell infiltration appeared less marked (570±23/10 HPF), and they formed smaller aggregates than those of B cells in pretreated patients, with P<0.01. However, 1 month after treatment with PPI, esophageal biopsies revealed a marked decrease in the number of both B (10±2/10 HPF) and T (290±12/HPF) cells in 66% of patients, with a P<0.01 in comparison with the pretherapy pattern. However, the remaining 33% of patients still showed a significantly high number of T cells (490±28/HPF), with a P <0.05 in comparison with the responder group that formed small aggregates with larger cell sizes, indicating their activation. Cytokine profiles before and after treatment revealed significant posttreatment reduction in their levels in the 132 cases with improvement in their clinical manifestations, and endoscopic and histopathologic findings, but there is no obvious change in the measured cytokine levels in 66 patients who simultaneously had no improvement in their endoscopic, histopathologic findings and mild improvement in their clinical manifestations. Moreover, significant posttreatment reduction of IL-8 and IL-1β in the 98 (49%) patients with Los Angeles grading B, C, and D was observed. With regard to serum levels of IL-10 and IL-4, there were no statistically significant differences before and after treatment with PPI. Peripheral blood immunologic parameters revealed a statistically significant reduction of the total CD3 absolute count, T-helper lymphocyte (CD4/CD3) percentage, T-helper lymphocyte absolute count, and the percentage and absolute cytotoxic T-lymphocyte count (CD8/CD3) after treatment with PPI. Moreover, the same significant difference of peripheral blood lymphocytes was detected after exclusion of patients with Los Angeles grade A, which may be considered normal.

CONCLUSIONS

Acid-induced T-cell-related cytokine production plays an important role in inflammation occurring in patients with GERD. Mucosal and peripheral inflammation reduces with PPI use.

The emerging role of epigenetic modifiers in repair of DNA damage associated with chronic inflammatory diseases

At sites of chronic inflammation epithelial cells are exposed to high levels of reactive oxygen species (ROS), which can contribute to the initiation and development of many different human cancers. Aberrant epigenetic alterations that cause transcriptional silencing of tumor suppressor genes are also implicated in many diseases associated with inflammation, including cancer. However, it is not clear how altered epigenetic gene silencing is initiated during chronic inflammation. The high level of ROS at sites of inflammation is known to induce oxidative DNA damage in surrounding epithelial cells. Furthermore, DNA damage is known to trigger several responses, including recruitment of DNA repair proteins, transcriptional repression, chromatin modifications and other cell signaling events. Recruitment of epigenetic modifiers to chromatin in response to DNA damage results in transient covalent modifications to chromatin such as histone ubiquitination, acetylation and methylation and DNA methylation. DNA damage also alters non-coding RNA expression. All of these alterations have the potential to alter gene expression at sites of damage. Typically, these modifications and gene transcription are restored back to normal once the repair of the DNA damage is completed. However, chronic inflammation may induce sustained DNA damage and DNA damage responses that result in these transient covalent chromatin modifications becoming mitotically stable epigenetic alterations. Understanding how epigenetic alterations are initiated during chronic inflammation will allow us to develop pharmaceutical strategies to prevent or treat chronic inflammation-induced cancer. This review will focus on types of DNA damage and epigenetic alterations associated with chronic inflammatory diseases, the types of DNA damage and transient covalent chromatin modifications induced by inflammation and oxidative DNA damage and how these modifications may result in epigenetic alterations.

Association of atrial fibrillation and gastroesophageal reflux disease: Natural and therapeutic linkage of the two common diseases

Atrial fibrillation (AF) is a common arrhythmia and gastroesophageal reflux disease (GERD) is popular in Japan. The two common diseases share several predisposing factors such as lifestyle and senescence, and inflammation and oxidative stress play an important role in their development and progression. Incidental cases of AF treated successfully by proton pump inhibitor (PPI) applied for coexisting GERD have been sporadically reported. An increasing evidence indicates that GERD induces the initiation and the perpetuation of AF. This is caused by the autonomic nerve influence, mechanical compression, and propagation of local inflammation due to proximity of left atrium (LA) and lower esophagus. Meanwhile, AF also develops GERD by mechanical and inflammatory actions of LA characterized by remodeling and inflammation. The robust association of AF with GERD is not limited to their natural interaction, i.e., pharmacological or nonpharmacological treatment of AF is reported to aggravate GERD. Many cardiac drugs (anticoagulants, calcium antagonists, and nitrates) induce esophageal mucosal damage and lower esophageal sphincter relaxation promoting acid reflux. These drugs are frequently prescribed in patients with AF for stroke prevention, rate control, and for coexisting coronary heart disease. Catheter ablation also yields both GERD and esophageal thermal injury, which is a precursor lesion of atrioesophageal fistula. The notion that AF and GERD are mutually interdependent is widely and empirically recognized. However, mechanistic link of the two common diseases and objective evaluation of PPI as an adjunctive AF treatment warrant future large-scale prospective trials.

Dichloromethane Extracts of Geranium Koreanum Kom. Alleviates Esophagus Damage in Acute Reflux Esophagitis-Induced Rats by Anti-Inflammatory Activities

Reflux esophagitis (RE) is a gastrointestinal disease caused by the reflux of gastric acid and stomach contents, and it leads to esophageal damage. Therefore, it is necessary to study the improvement of esophageal damage on a RE-induced model. The present study was accomplished to demonstrate the protective effects of a dichloromethane fraction of Geranium koreanum (DGK) plant on esophageal damage in an acute RE rat model. First, we examined the potential of anti-inflammatory effects of various fractions measured by cell cytotoxicity, morphological changes and nitric oxide (NO) production on lipopolysaccharide (LPS)-induced Raw 264.7 macrophage cells. Then, to evaluate the protective effects on RE, rats were partitioned into the following groups: normal control, RE-induced control and RE rats pre-treated with DGK 100 and 200 mg/kg body weight. The esophageal mucosal ulcer ratio was measured by the Image J program and histological changes were examined using a hematoxylin and eosin staining of the esophageal mucosa. The expression of pro-inflammatory proteins, cytokines and tight junction proteins involved in the esophageal mucosal damage were investigated using Western blotting and an enzyme-linked immunosorbent assay (ELISA) kit with esophagus tissue. DGK chemical profile and phenolic contents were analyzed by liquid chromatography-mass spectrometry (LC-MS/MS). The results showed that DGK exhibited anti-inflammatory effects against LPS-stimulated cells by significantly inhibiting NO production. Additionally, the results in vivo showed that improvement effects of DGK on esophageal mucosal damage. The expression of inflammatory proteins involved in nuclear factor κB (NF-κB) signaling pathways and tight junction protein (claudin-4 and -5) were significantly decreased in esophageal mucosa. We found the potential of DGK as source of replacement therapy products for inflammatory and RE disease.

Antioxidant Activity of Myrtus communis L. and Myrtus nivellei Batt. & Trab. Extracts: A Brief Review

Myrtus communis L. (myrtle) and Myrtus nivellei Batt. & Trab. (Saharan myrtle) have been used in folk medicine for alleviating some ailments. M. communis is largely distributed in the Mediterranean Basin, whereas M. nivellei is confined in specific zones of the central Saharan mountains. The chemical composition and antioxidant activity of berry and leaf extracts isolated from myrtle are deeply documented, whereas those isolated from Saharan myrtle extracts are less studied. In both species, the major groups of constituents include gallic acid derivatives, flavonols, flavonol derivatives, and hydroxybenzoic acids. In coloured berries, anthocyanins are also present. In M. nivellei extracts are reported for some compounds not described in M. communis so far: 2-hydroxy-1,8-cineole-β-d-glucopyranoside, 2-hydroxy-1,8-cineole 2-O-α-l-arabinofuranosyl (1→6)-β-d-glucopyranoside, rugosin A, and rugosin B. Berries and leaves extracts of both species had antioxidant activity. Comparative studies of the antioxidant activity between leaf and berry myrtle extracts revealed that leaf extracts are best antioxidants, which can be assigned to the galloyl derivatives, flavonols, and flavonols derivatives, although the ratio of these groups of compounds might also have an important role in the antioxidant activity. The anthocyanins present in myrtle berries seem to possess weak antioxidant activity. The antioxidant activity of sample extracts depended on various factors: harvesting time, storage, extraction solvent, extraction type, and plant part used, among other factors. Leaf extracts of myrtle revealed to possess anti-inflammatory activity in several models used. This property has been attributed either to the flavonoids and/or hydrolysable tannins, nevertheless nonprenylated acylphloroglucinols (e.g., myrtucommulone and semimyrtucommulone) have also revealed a remarkable role in that activity. The biological activities of myrtle extracts found so far may direct its use towards for stabilizing complex lipid systems, as prebiotic in food formulations, and as novel therapeutic for the management of inflammation.

Protease-mediated Inflammation: An In Vitro Human Keratinocyte-based Screening Tool for Anti-inflammatory Drug Nanocarrier Systems

Background:

Refined encapsulation approaches in dermatotherapy gain increased interest. There is need of reproducible in vitro systems representing disease features to screen drug delivery systems for preclinical assessment. Inflammatory human skin diseases are commonly accompanied by abnormal epidermal differentiation and barrier impairment. Serine proteases (SPs) and their inhibitors play a critical role in such dysfunctional differentiation. SPs also initiate cellular pathways via activation of protease-activated receptors, which contribute to inflammation. Thus, function and activity of SPs should be considered for the design of new therapies of such disorders.

Objectives:

Herein, we established a novel simplified cell culture model, based on SP-mediated inflammation suitable to assess nanocarriers loaded with anti-inflammatory drugs.

Methods:

SP-mediated inflammation and the regulatory effect of free or encapsulated dexamethasone were determined by measuring interleukin-6 and interleukin-8 in culture medium of HaCaT (human adult low calcium temperature)-keratinocytes. Additionally, radical formation was analyzed by electron paramagnetic resonance spectroscopy. Cellular uptake of core-multishell nanocarriers was investigated by fluorescence microscopy. Cytotoxicity of all additives was determined by a viability assay.

Results:

SP-Stimulation of keratinocytes resulted in increased radical production and release of inflammatory cytokines without affecting cell viability. Induced inflammation was successfully downregulated by addition of free or encapsulated dexamethasone.

Conclusion:

SP-addition can be used as inflammatory stimulus in cell culture to mimic effects of aberrant enzymatic activities found in skin of atopic dermatitis patients. The set-up is appropriate as a preliminary test to examine the effectiveness of new molecules or delivery-systems to counteract serine protease-mediated inflammatory processes prior to skin studies.

Role of NRF2 in protection of the gastrointestinal tract against oxidative stress

The gastrointestinal tract is exposed to a variety of noxious factors, such as Helicobacter pylori, nonsteroidal anti-inflammatory drugs, gastric acid, ischemia-reperfusion, and mental stresses. Theses stressors generate free radicals within gastrointestinal tissues, causing organ injury and functional disturbance. Although the gastrointestinal tract can withstand such oxidative stresses to some extent by enhancing its antioxidant system via nuclear factor erythroid 2-related factor 2-Kelch-like erythroid cell-derived protein with CNC homology-associated protein 1-mediated pathways, acute or chronic exposure to oxidative stress can cause several gastrointestinal tract disorders, such as inflammation, ulcers, cancers, and various functional disturbances. Recent studies have demonstrated that some natural compounds and drugs can upregulate the nuclear factor erythroid 2-related factor 2-mediated antioxidant system, ameliorating or preventing these disorders. Although these compounds may be useful as chemopreventive agents, sufficient evidence for their clinical efficacy has not yet been provided. In addition, it is important to note that excessive nuclear factor erythroid 2-related factor 2 stimulation can be harmful to human health, especially from the standpoint of tumor biology.

Modulation of the oxidative plasmatic state in gastroesophageal reflux disease with the addition of rich water molecular hydrogen: A new biological vision

Gastroesophageal reflux disease (GERD), a clinical condition characterized by reflux of gastroduodenal contents in the oesophagus, has proved to demonstrate a strong link between oxidative stress and the development of GERD. Proton pump inhibitors (PPIs) have been universally accepted as first-line therapy for management of GERD. The potential benefits of electrolysed reduced water (ERW), rich in molecular hydrogen, in improving symptoms and systemic oxidative stress associated with GERD was assessed. The study was performed on 84 GERD patients undergoing control treatment (PPI + tap water) or experimental treatment (PPI + ERW) for 3 months. These patients were subjected to the GERD-Health Related Quality of Life Questionnaire as well as derivatives reactive oxigen metabolites (d-ROMs) test, biological antioxidant potential (BAP) test, superoxide anion, nitric oxide and malondialdehyde assays, which were all performed as a proxy for the oxidative/nitrosative stress and the antioxidant potential status. Spearman's correlation coefficient was used to evaluate the correlation between scores and laboratory parameters. Overall results demonstrated that an optimal oxidative balance can be restored and GERD symptoms can be reduced rapidly via the integration of ERW in GERD patients. The relative variation of heartburn and regurgitation score was significantly correlated with laboratory parameters. Thus, in the selected patients, combination treatment with PPI and ERW improves the cellular redox state leading to the improvement of the quality of life as demonstrated by the correlation analysis between laboratory parameters and GERD symptoms.

A novel murine model of esophageal nonerosive reflux disease: from inflammation to impairment in mucosal integrity

Nonerosive reflux disease (NERD) is a highly prevalent phenotype of the gastroesophageal reflux disease. In this study, we developed a novel murine model of NERD in mice with microscopic inflammation and impairment in the epithelial esophageal barrier. Female Swiss mice were subjected to the following surgical procedure: the transitional region between the forestomach and the glandular portion of the stomach was ligated, and a nontoxic ring was placed around the duodenum near the pylorus. The control group underwent sham surgery. The animals were euthanized at 1, 3, 7, and 14 days after surgery. Survival and body weight were monitored daily. Esophageal wet weight, macroscopic lesion, histopathological alterations, myeloperoxidase (MPO) activity, cytokine levels, transepithelial electrical resistance (TEER), and mucosal permeability were evaluated. The survival rate was 78% at 14 days, with mild loss in body weight. Surgery did not induce erosive esophagitis but instead induced microscopic inflammation and increased esophageal wet weight, IL-6, keratinocyte-derived cytokine (KC) levels, and MPO activity with maximal peak between 3 and 7 days and resolution at 14 days postsurgery. Epithelial esophageal barrier was evaluated in operated mice at 7 and 14 days postsurgery; a decrease in TEER and increase in the esophageal epithelial permeability were observed compared with the sham-operated group. In addition, the inhibition of acid secretion with omeprazole significantly prevented the esophageal inflammation and impairment of barrier function at 7 days postsurgery. Thus we established a novel experimental model of NERD in mice, which can contribute to understanding the pathophysiological events associated with NERD.NEW & NOTEWORTHY In this study, we standardized an experimental model of nonerosive reflux disease (NERD) in mice. This model involves an acute inflammatory response followed by impaired esophageal mucosal integrity, even in the absence of inflammation. Thus this model can serve for evaluation of pathophysiological aspects of NERD and open new perspectives for therapeutic strategies for patients with this disorder.

Medicinal Plants for Management of Gastroesophageal Reflux Disease: A Review of Animal and Human Studies

OBJECTIVES

Gastroesophageal reflux disease (GERD) is a prevalent gastrointestinal disease that causes troublesome symptoms and/or complications. The major therapeutic strategy for GERD focuses mainly on symptom alleviation using proton pump inhibitors (PPIs), which does not produce a perfect response in all patients. An approach with new therapeutic agents for GERD seems to be essential. The aim of this study was to review animal and human studies investigating the effect of medicinal plants in GERD as well as mechanisms underlying their therapeutic effects.

METHODS

Medline, Scopus, and Cochrane Central Register of Controlled Trials were searched for animal or human studies. The data collected covered January 1966-October 2015.

RESULTS

A total of 22 studies were included in this review, of which nine were animal studies and 13 were human studies. Ceratonia siliqua as a medicinal plant and rikkunshito as a multicomponent herbal preparation were the most frequently studied herbal medicines in GERD. Antioxidant and anti-inflammatory activities were the main mechanisms demonstrated in animal studies for ameliorating the effects of medicinal plants in GERD. Other mechanisms include downregulation of genes encoding inflammatory proteins, improvement of barrier function and gastric mucus, a decrease in gastric acid, and induction of tonic contractions of the lower esophageal sphincter. All herbal preparations used in human studies have led to the alleviation of symptoms related to GERD. Myrtus communis and Cydonia oblonga showed marked reduction in GERD symptoms comparable to omeprazole. The therapeutic effect of Cydonia oblonga persisted after discontinuation of the drug. Tongjlang and rikkunshito showed therapeutic effects for non-erosive reflux disease (NERD) where PPIs failed to show a promising effect. Studies on Ceratonia siliqua have been solely focused on regurgitation in infants, and a remarkable decrease in the number of regurgitations was demonstrated.

CONCLUSION

The multiple mechanisms of action of medicinal plants in GERD other than anti-secretory properties appear to provide more efficient treatment and helped to manage the histopathological changes associated with this disorder. Further studies are needed to understand the effects of medicinal plants on GERD better.

Contribution of immunomodulators to gastroesophageal reflux disease and its complications: stromal cells, interleukin 4, and adiponectin

Gastroesophageal reflux disease (GERD) has become the most commonly seen gastrointestinal disorder in outpatient clinics. In the United States, around 20% of the general population experience heartburn on a weekly basis. Although clinical complaints can be mild or moderate, patients with GERD may develop further complications, such as peptic strictures, Barrett's esophagus (BE), and even esophageal adenocarcinoma. Pathologically, GERD is developed as a result of chronic and enhanced exposure of the esophageal epithelium to noxious gastric refluxate. In this review article, we provide an overview of GERD and then focus on the roles of stromal cells, interleukin 4, and adiponectin in GERD and BE. The importance of inflammation and immunomodulators in GERD pathogenesis is highlighted. Targeting the immunomodulators or inflammation in general may improve the therapeutic outcome of GERD, in particular, in those refractory to proton pump inhibitors.

Antioxidant and Anti-Inflammatory Effects of Rhei Rhizoma and Coptidis Rhizoma Mixture on Reflux Esophagitis in Rats

The purpose of this study was to investigate the antioxidant and anti-inflammatory effects of the combined extract of Rhei rhizoma and Coptidis rhizoma (RC-mix) in experimental model of acute reflux esophagitis. The antioxidant activity was assessed by in vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. RC-mix was given at 100, 200, and 400 mg/kg body weight 2 h prior to induction of reflux esophagitis (RE). After 5 h, the effects of RC-mix treated rats were compared with those of normal and control rats. The representative flavonoid contents of RC-mix, such as sennoside A, epiberberine, coptisine, palmatine, and berberine, were detected using HPLC. The elevated esophageal mucosa damage was markedly ameliorated by RC-mix treatment in a dose-dependent manner. Furthermore, the administration of RC-mix reduced the increase of serum reactive oxygen species (ROS) and peroxynitrite (ONOO(-)). The improvement of superoxide dismutase (SOD) and heme oxygenase-1 (HO-1) levels were marked in the group given RC-mix. Moreover, the elevation of inflammatory mediators and cytokines by nuclear factor-kappa B (NF-κB) activation in control rats decreased by RC-mix pretreatment. These results indicate that RC-mix treatment reduces the pathological states of esophagitis via regulating NF-κB mediated inflammation related to oxidative stress.

Esophageal Epithelial-Derived IL-33 Is Upregulated in Patients with Heartburn

Background

Interleukin-33 (IL-33) is a tissue-derived cytokine that is constitutively expressed in epithelial cells of tissues exposed to the environment and plays a role in sensing damage caused by inflammatory diseases. IL-33 acts as both a traditional cytokine and as a chromatin-associated nuclear factor in both innate and adaptive immunity. We recently showed that IL-33 in esophageal mucosa is upregulated in reflux esophagitis. However, IL-33 expression in patients with heartburn without mucosal injury and its relationship with intercellular space (ICS) have never been examined. We therefore examined the expression of cytokines and ICS in patients with heartburn.

Methods

The expression of IL-33 in the middle and distal esophageal mucosa of patients with heartburn without mucosal break and control samples was examined using real-time RT-PCR and immunofluorescence. The mRNA expression of IL-6, IL-8, MCP-1, and RANTES, and ICS was also analyzed.

Results

IL-33 expression and the mean ICS were significantly increased in the mucosa of patients with heartburn compared to that of the control. IL-33 and ICS were not different between the patients who were taking a PPI and those who were not. The upregulated IL-33 expression in the heartburn group was located in the nuclei of the basal cell layer. Although IL-6, IL-8, MCP-1 and RANTES levels were not different between control and patients with heartburn samples, IL-33 mRNA levels were still significantly correlated with IL-6, IL-8, or MCP-1 mRNA levels.

Conclusion

Nuclear IL-33 is upregulated in patients with heartburn. Upregulated IL-33 in heartburn patients is related to the symptoms.

Efficacy and safety of Aloe vera syrup for the treatment of gastroesophageal reflux disease: a pilot randomized positive-controlled trial

OBJECTIVE

To investigate the use of Aloe vera (A. vera) for the treatment of gastroesophageal reflux disease (GERD) symptoms and compare its effects with those of omeprazole and ranitidine.

METHODS

In this pilot, randomized controlled trial, 79 subjects were allocated to A. vera syrup (standardized to 5.0 mg polysaccharide per mL of syrup) at a dose of 10 mL/d, omeprazole capsule (20 g/d) or ranitidine tablet (150 mg in a fasted state in the morning and 150 mg 30 min before sleep at night) for a period of 4 weeks. The frequencies of eight main symptoms of GERD (heartburn, food regurgitation, flatulence, belching, dysphagia, nausea, vomiting and acid regurgitation) were assessed at weeks 2 and 4 of the trial.

RESULTS

A. vera was safe and well tolerated and reduced the frequencies of all the assessed GERD symptoms, with no adverse events requiring withdrawal.

CONCLUSION

A. vera may provide a safe and effective treatment for reducing the symptoms of GERD.

The epidemic of oesophageal carcinoma: Where are we now?

Since the early 1970s, the incidence of oesophageal adenocarcinoma has increased dramatically in most Western populations. In contrast, the incidence of oesophageal squamous-cell carcinoma has decreased in these same populations. Epidemiological studies conducted over the past decade have provided great insights into the etiology of oesophageal cancer. These studies have identified gastro-oesophageal reflux disease, obesity and cigarette smoking as risk factors for oesophageal adenocarcinoma, while use of nonsteroidal anti-inflammatory drugs and infection with Helicobacter pylori are associated with reduced risk of oesophageal adenocarcinoma. For oesophageal squamous-cell carcinoma, alcohol and cigarette smoking are the two major risk factors underlying most cases. This review combines a synthesis of these studies with an analysis of data from the United States National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program to discuss the change in incidence of oesophageal cancer and summarize current knowledge of risk factors.

Choline and Cystine Deficient Diets in Animal Models with Hepatocellular Injury: Evaluation of Oxidative Stress and Expression of RAGE, TNF-α, and IL-1β

This study aims to evaluate the effects of diets deficient in choline and/or cystine on hepatocellular injury in animal models (young male Wistar rats, aged 21 days), by monitoring some of the oxidative stress biomarkers and the expression of RAGE, TNF-α, and IL-1β. The animals were divided into 6 groups (n = 10) and submitted to different diets over 30 days: AIN-93 diet (standard, St), AIN-93 choline deficient (CD) diet and AIN-93 choline and cystine deficient (CCD) diet, in the pellet (pl) and powder (pw) diet forms. Independently of the diet form, AIN-93 diet already led to hepatic steatosis and CD/CCD diets provoked hepatic damage. The increase of lipid peroxidation, represented by the evaluation of thiobarbituric acid reactive species, associated with the decrease of levels of antioxidant enzymes, were the parameters with higher significance toward redox profile in this model of hepatic injury. Regarding inflammation, in relation to TNF-α, higher levels were evidenced in CD_(pl), while, for IL-1β, no significant alteration was detected. RAGE expression was practically the same in all groups, with exception of CCD_(pw) versus CCD_(pl). These results together confirm that AIN-93 causes hepatic steatosis and choline and/or cysteine deficiencies produce important hepatic injury associated with oxidative stress and inflammatory profiles.

Effect of lycopene against gastroesophageal reflux disease in experimental animals

BACKGROUND

Lycopene is a robust antioxidant with significant antiulcer activity. Henceforth, the present study was ventured to elucidate the effect of lycopene on experimental esophagitis.

METHODS

Groups of rats were subjected to forestomach and pylorus ligation with subsequent treatment with lycopene (50 and 100 mg/kg, po) and pantoprazole (30 mg/kg, po).

RESULTS

Treatment with lycopene evidenced sententious physiological protection when scrutinized for pH, acidity (total and free), volume of gastric juices and esophagitis index. Lycopene further embarked diminishing effect on oxidative stress through synchronising lipid and protein peroxidation along with regulating the enzymatic activity of SOD and catalase. Lycopene also modified the levels of immunoregulatory cytokines (IL- 1β and IL-6) favourably. The dose dependent efficacy of lycopene in the current experimental condition was also attested when exemplified morphologically through scanning electron microscopy.

CONCLUSION

From the current line of evidences, it was concluded that lycopene can impart momentous protection against experimental esophagitis by wrapping up the reactive oxygen species and through dual inhibition of the arachidonic acid pathway.

The inhibitory effect of PIK-75 on inflammatory mediator response induced by hydrogen peroxide in feline esophageal epithelial cells

Isoform-selective inhibitors of phosphoinositide 3-kinase (PI3K) activation have an anti-inflammatory effect by reducing proinflammatory cytokines. Cultured feline esophageal epithelial cells (EEC) of passages 3~4 were treated with hydrogen peroxide and PIK-75. The cell viability was measured by a MTT incorporation assay. The distribution of PI3K isoforms, p-Akt, IL-1β, and IL-8 was inferred from Western blots. The release of IL-6 was determined by ELISA. The cell morphology was not considerably different from nontreated cells if the cells were pretreated with PIK-75 and treated with 300 μM hydrogen peroxide. The density of p110α of PI3K was increased, but that of other types was not affected after the treatment with hydrogen peroxide. The density of p-Akt, when the cells were exposed to PIK-75 and hydrogen peroxide, was diminished dose dependently more than that of hydrogen peroxide treatment only. The decrease of p-Akt showed an inhibition of PI3K by PIK-75. PIK-75 dose dependently reduced the expression of IL-1β, IL-8, and the level of IL-6 compared with hydrogen peroxide treatment only. These results suggest evidence that p110α mediates esophageal inflammation and that PIK-75 has an anti-inflammatory effect by reducing proinflammatory cytokines on feline esophageal epithelial cultured cells.

Nrf2 deficiency impairs the barrier function of mouse oesophageal epithelium

OBJECTIVE

As a major cellular defence mechanism, the Nrf2/Keap1 pathway regulates expression of genes involved in detoxification and stress response. Here we hypothesise that Nrf2 is involved in oesophageal barrier function and plays a protective role against gastro-oesophageal reflux disease (GERD).

DESIGN

Human oesophageal biopsy samples, mouse surgical models and Nrf2(-/-) mice were used to assess the role of the Nrf2/Keap1 pathway in oesophageal barrier function. Trans-epithelial electrical resistance (TEER) was measured with mini-Ussing chambers. HE staining and transmission electron microscopy were used to examine tissue morphology, while gene microarray, immunohistochemistry, western blotting and chromatin immunoprecipitation (ChIP) analysis were used to assess gene expression.

RESULTS

Nrf2 was expressed in normal oesophageal epithelium and activated in GERD of both humans and mice. Nrf2 deficiency and gastro-oesophageal reflux in mice, alone or in combination, reduced TEER and increased intercellular space in oesophageal epithelium. Nrf2 target genes and gene sets associated with oxidoreductase activity, mitochondrial biogenesis and energy production were downregulated in the oesophageal epithelium of Nrf2(-/-) mice. Consistent with the antioxidative function of Nrf2, a DNA oxidative damage marker (8OHdG) dramatically increased in oesophageal epithelial cells of Nrf2(-/-) mice compared with those of wild-type mice. Interestingly, ATP biogenesis, Cox IV (a mitochondrial protein) and Claudin 4 (Cldn4) expression were downregulated in the oesophageal epithelium of Nrf2(-/-) mice, suggesting that energy-dependent tight junction integrity was subject to Nrf2 regulation. ChIP analysis confirmed the binding of Nrf2 to Cldn4 promoter.

CONCLUSIONS

Nrf2 deficiency impairs oesophageal barrier function through disrupting energy-dependent tight junction.

Protective effects of D-002 on experimentally induced gastroesophageal reflux in rats

AIM: To investigate the effects of beeswax alcohols (D-002) on the esophageal damage induced by gastroesophageal reflux (GER) in rats.

METHODS: Sixty male rats were randomized into six groups (10 rats/group): a negative control and five groups with experimentally induced GER: a positive vehicle control, three treated with D-002 (25, 100 and 200 mg/kg, respectively), and one with omeprazole 10 mg/kg. All treatments were given by gastric gavage. One hour after dosing, GER was produced by simultaneous ligation of the pyloric end and the forestomach. Esophageal lesions index (ELI), gastric secretion volume and acidity, and esophageal malondialdehyde (MDA) and sulfhydryl (SH) group concentrations were measured. Statistical significance was considered at P < 0.05.

RESULTS: As compared to the negative control, the positive control group exhibited increased ELI (5.2 ± 0.33 vs 0 ± 0, P = 0.0003), gastric secretion volume (2.69 ± 0.09 vs 0.1 ± 0.0, P = 0.0003) and acidity (238 ± 19.37 vs 120.0 ± 5.77, P = 0.001), and esophageal concentrations of MDA (2.56 ± 0.1 vs 1.76 ± 0.28, P = 0.001) and SH groups (1.02 ± 0.05 vs 0.56 ± 0.08, P = 0.0003). D-002 (25, 100 and 200 mg/kg) reduced ELI (3.36 ± 0.31, 2.90 ± 0.46 and 2.8 ± 0.23, respectively) vs the positive control (5.2 ± 0.33) (P = 0.004; P = 0.002; P = 0.001, respectively). There were no significant changes in acidity with D-002 treatment, and only the highest dose reduced the volume of the gastric secretion (1.92 ± 0.25) vs the positive control (2.69 ± 0.09, P = 0.013). D-002 (25, 100 and 200 mg/kg) lowered the esophageal MDA (2.05 ± 0.16, 1.98 ± 0.22 and 1.93 ± 0.22, respectively) (P = 0.01; P = 0.03; P = 0.03, respectively) and SH group concentration (0.87 ± 0.06, 0.79 ± 0.08 and 0.77 ± 0.06, respectively) (P = 0.04; P = 0.04; P = 0.02) vs the positive control (2.56 ± 0.10 and 1.02 ± 0.05, respectively). Omeprazole decreased ELI (2.54 ± 0.47), gastric secretion volume (1.97 ± 0.14) and acidity (158.5 ± 22.79), esophageal MDA (1.87 ± 0.13) and SH group (0.72 ± 0.05) concentrations vs the positive control (P = 0.002; P = 0.001; P = 0.02; P = 0.003; P = 0.002, respectively).

CONCLUSION: Acute oral administration of D-002 decreased macroscopic esophageal lesions and oxidative stress in rats with experimentally induced GER, without modifying gastric secretion acidity.

How good is the neosquamous epithelium?

BACKGROUND/AIMS

Endoscopic radiofrequency ablation of dysplastic Barrett's esophagus (BE) combined with proton pump inhibitor therapy is commonly utilized for preventing progression of dysplastic BE to esophageal adenocarcinoma. Fundamental to the success of this and all ablative approaches is the healing of the ablated areas of BE with a stratified squamous epithelium referred to as 'neosquamous epithelium' (NSE). Although NSE appears 'normal' endoscopically, the reemergence of BE over time in the previously ablated segments raises the question of the health and integrity of NSE.

METHODS

The health of NSE was recently investigated in endoscopic biopsies in vitro in a group of patients after ablation while on proton pump inhibitors. Biopsies of NSE were compared to upper squamous epithelium (USE) from the same patients morphologically (light microscopy) and with respect to barrier function by measuring electrical resistance and fluorescein flux in mini-Ussing chambers.

RESULTS

Compared to USE, NSE exhibited dilated intercellular spaces and inflammation and defective barrier function by low electrical resistance and high fluorescein flux. Moreover, NSE exhibited downregulation of claudin-4, a highly expressed protein in squamous tight junctions.

CONCLUSION

NSE has defective barrier function in part due to downregulation of claudin-4. Since downregulation of claudin-4 increases paracellular permeability to cations, e.g. hydrogen ions, NSE is more vulnerable to attack and damage by acidic and weakly acidic refluxates--a phenomenon that may contribute in part to the reemergence of BE.

NFkB and Nrf2 in esophageal epithelial barrier function

The stratified squamous epithelium of the esophagus forms a tight protective barrier. Defects of the barrier function contribute to gastroesophageal reflux disease (GERD), which is manifested as damage to the esophageal epithelium due to exposure to the gastrointestinal refluxate. In this review, we discuss the involvement of NFkB and Nrf2 in esophageal epithelial barrier function. Understanding these molecular pathways in the esophagus may help us develop therapeutic strategies to improve clinical outcomes in patients with GERD.

Role of nociceptors/neuropeptides in the pathogenesis of visceral hypersensitivity of nonerosive reflux disease

BACKGROUND AND AIMS

Esophageal visceral hypersensitivity has been proposed to be a pathogenesis of heartburn in nonerosive reflux disease (NERD), but its further mechanisms are unclear. Recently, it has been suggested that nociceptors and neuropeptides control sensory and pain mechanisms. Therefore, the objective of the present study was to estimate expression of acid-sensitive nociceptors such as transient receptor potential vanilloid 1 (TRPV1) and acid-sensing ion channel 3, protease-activated receptor 2 (PAR2), neuropeptides such as substance P and calcitonin-gene-related peptide, and their receptors such as neurokinin 1 receptor (NK1R) and receptor activity-modifying protein 1 in the esophageal mucosa of NERD patients.

METHODS

Biopsy samples were taken from NERD patients and healthy control subjects without heartburn. The expression level of nociceptors, neuropeptides, and their receptors were assessed by real-time RT-PCR and enzyme immunoassay. Localization of substance P and CGRP in the esophageal mucosa was determined by immunohistochemical staining.

RESULTS

Expression of mRNA for TRPV1 and PAR2 was significantly elevated in the esophageal mucosa of NERD patients. Substance P protein level and its receptor NK1R mRNA also increased in NERD patients. A positive correlation between the substance P protein level and reflux symptoms was observed. Immunohistochemical study revealed the presence of substance P-positive nerves in the lamina propria of the esophagus.

CONCLUSIONS

These findings suggest that visceral hypersensitivity in NERD patients is involved in neurogenic inflammation showing the increase in both substance P release and NK1R expression, which may be associated with the activation of TRPV1 and PAR2.