Reflux-related gastric mucosal injury is associated with increased mucosal histamine content in humans

Histopathological differences in pediatric duodenogastric reflux: a comparative study

The histopathological effects of duodenogastric reflux (DGR) in children remain poorly described. This study aimed to evaluate and compare the gastric histopathological findings of pediatric patients with endoscopically confirmed DGR gastritis and those without, to identify potential morphological changes associated with bile reflux in childhood. This retrospective study compared children with endoscopically confirmed DGR to age- and sex-matched controls without DGR. Gastric biopsy samples were re-evaluated by a single pathologist blinded to clinical data. Histopathological features, including inflammation severity, activity, fibrosis, vascular congestion, edema, foveolar hyperplasia, the presence of Helicobacter pylori, lymphoid aggregates, reactive gastropathy, intestinal metaplasia, and glandular atrophy were compared. Logistic regression was used to identify significant predictors of DGR. A total of 73 patients with DGR and 65 controls were included. Fibrosis (60.2% vs. 9.2%, p < 0.001), congestion (63.0% vs. 27.7%, p < 0.001), foveolar hyperplasia (32.9% vs. 6.2%, p < 0.001), and edema (24.7% vs. 6.2%, p = 0.003) were significantly more common in the DGR group. Logistic regression identified foveolar hyperplasia (OR 10.67), edema (OR 9.01), fibrosis (OR 6.98), and congestion (OR 5.85) as independent predictors of DGR.

CONCLUSION

Fibrosis, congestion, foveolar hyperplasia, and edema are significantly associated with DGR in pediatric patients and may serve as supportive histological markers for diagnosis.

WHAT IS KNOWN

• DGR in children lacks a standardized diagnostic method, with endoscopy and histopathology being commonly used. • Histopathological features such as foveolar hyperplasia and fibrosis are known in adults but less studied in children.

WHAT IS NEW

• This study identifies fibrosis, congestion, foveolar hyperplasia, and edema as significant histopathological markers in pediatric DGR. • It suggests that endoscopic findings, combined with histopathology, can aid in the diagnosis of DGR in children.

Continuous Gastric pH Monitoring in Children Facilitates Better Understanding of Gastroesophageal Reflux Disease: A Prospective Observational Study

Objectives: Gastroesophageal reflux disease (GERD) is commonly encountered in adults and children. A subset of patients with GERD are refractory to acid suppressants, implicating other factors in the refluxate. Duodenogastric reflux (DGR) produces similar symptoms through reflux of non-acidic duodenal content and the cytotoxic effect of bile in the esophageal mucosa. Various methods have been utilized to detect DGR using a Bilitec device or Hepatobiliary scintigraphy, amongst the most common, each with their own limitations. We aimed to use combined multichannel intraluminal impedance and pH (MII-pH) monitoring with an additional gastric pH sensor to collect information about acidic and non-acidic gastroesophageal refluxes and to assess whether continuous gastric pH measurement in children provides indirect evidence of DGR for better understanding of the symptoms. Methods: From 2022 through 2023, clinically symptomatic pediatric patients scheduled for esophagogastroduodenoscopy (EGD) and MII-pH at Arnold Palmer Hospital for Children in the United States were included (n = 26). Exclusions included patients taking acid suppressants prior to the start of this study. The data were analyzed for subjects completing at least 18 h of the study protocol. Results: Subjects with a normal pH impedance (n = 5) showed a median non-meal gastric pH of 1.8. Subjects with an abnormal pH impedance (n = 21) showed a median non-meal gastric pH of 2.2. Of the 26 subjects enrolled, the duration of non-meal gastric pH 4.0-7.0 was positively correlated with non-acidic gastroesophageal refluxes. Although all acidic reflux events occurred at gastric pH < 4.0, there was no correlation between the duration of non-meal gastric pH < 4.0 and impedance changes or reflux index. Conclusions: The results showed daily variability in the non-meal gastric pH of pediatric patients and a statistically significant correlation between its duration at pH 4.0 to 7.0 and non-acidic refluxes suggestive of the implication of DGR. Further research is required to assess this association with gastroesophageal reflux and dyspeptic symptoms to investigate the diagnostic tools and therapeutic interventions, including the role of prokinetics and surface protective agents for DGR.

Diagnostic Principles for Chronic Gastritis Associated with Duodenogastric Reflux

This article systematizes available data from the literature on biliary gastritis (BG) in order to increase the awareness of specialists about the latest possibilities for diagnosing the disease. BG occurs as a result of pathological duodenogastric reflux. In patients with a preserved duodenogastric junction, the dominant factor is represented by motor disorders of the upper digestive tract (primary biliary gastritis), while in patients recovering from surgical interventions it is represented by structural changes (secondary biliary gastritis). Progressive BG can lead to atrophy of the gastric mucosa, intestinal metaplasia, epithelial dysplasia, and eventually to gastric cancer. Diagnostic methods for BG are carried out to identify risk factors, exclude alarm symptoms and identify persistent motor disorders and pathological reflux (24 h pH-impedancemetry, hepatobiliary scintigraphy, 24 h monitoring of bilirubin content in the reflux using a Bilitec 2000 photometer), as well as to diagnose gastritis itself (esophagogastroduodenoscopy, morphological gastrobiopsy examination). The diagnosis of BG should be based on a multidisciplinary approach that combines a thorough analysis of a patient’s complaints, an anamnesis of the disease, and the results of endoscopic and histological research methods.

Diagnostic Principles for Chronic Gastritis Associated with Duodenogastric Reflux

This article systematizes available data from the literature on biliary gastritis (BG) in order to increase the awareness of specialists about the latest possibilities for diagnosing the disease. BG occurs as a result of pathological duodenogastric reflux. In patients with a preserved duodenogastric junction, the dominant factor is represented by motor disorders of the upper digestive tract (primary biliary gastritis), while in patients recovering from surgical interventions it is represented by structural changes (secondary biliary gastritis). Progressive BG can lead to atrophy of the gastric mucosa, intestinal metaplasia, epithelial dysplasia, and eventually to gastric cancer. Diagnostic methods for BG are carried out to identify risk factors, exclude alarm symptoms and identify persistent motor disorders and pathological reflux (24 h pH-impedancemetry, hepatobiliary scintigraphy, 24 h monitoring of bilirubin content in the reflux using a Bilitec 2000 photometer), as well as to diagnose gastritis itself (esophagogastroduodenoscopy, morphological gastrobiopsy examination). The diagnosis of BG should be based on a multidisciplinary approach that combines a thorough analysis of a patient's complaints, an anamnesis of the disease, and the results of endoscopic and histological research methods.

Alteration of gastric microbiota and transcriptome in a rat with gastric intestinal metaplasia induced by deoxycholic acid

Objective

Bile reflux plays a key role in the development of gastric intestinal metaplasia (GIM), an independent risk factor of gastric cancer. Here, we aimed to explore the biological mechanism of GIM induced by bile reflux in a rat model.

Methods

Rats were treated with 2% sodium salicylate and allowed to freely drink 20 mmol/L sodium deoxycholate for 12 weeks, and GIM was confirmed by histopathological analysis. Gastric microbiota was profiled according to the 16S rDNA V3-V4 region, gastric transcriptome was sequenced, and serum bile acids (BAs) were analyzed by targeted metabolomics. Spearman's correlation analysis was used in constructing the network among gastric microbiota, serum BAs, and gene profiles. Real-time polymerase chain reaction (RT-PCR) measured the expression levels of nine genes in the gastric transcriptome.

Results

In the stomach, deoxycholic acid (DCA) decreased the microbial diversity but promoted the abundances of several bacterial genera, such as Limosilactobacillus, Burkholderia-Caballeronia-Paraburkholderia, and Rikenellaceae RC9 gut group. Gastric transcriptome showed that the genes enriched in gastric acid secretion were significantly downregulated, whereas the genes enriched in fat digestion and absorption were obviously upregulated in GIM rats. The GIM rats had four promoted serum BAs, namely cholic acid (CA), DCA, taurocholic acid, and taurodeoxycholic acid. Further correlation analysis showed that the Rikenellaceae RC9 gut group was significantly positively correlated with DCA and RGD1311575 (capping protein-inhibiting regulator of actin dynamics), and RGD1311575 was positively correlated with Fabp1 (fatty acid-binding protein, liver), a key gene involved in fat digestion and absorption. Finally, the upregulated expression of Dgat1 (diacylglycerol acyltransferase 1) and Fabp1 related to fat digestion and absorption was identified by RT-PCR and IHC.

Conclusion

DCA-induced GIM enhanced gastric fat digestion and absorption function and impaired gastric acid secretion function. The DCA-Rikenellaceae RC9 gut group-RGD1311575/Fabp1 axis might play a key role in the mechanism of bile reflux-related GIM.

Roles and action mechanisms of bile acid-induced gastric intestinal metaplasia: a review

Gastric intestinal metaplasia (IM) is a precancerous lesion that increases the risk of subsequent gastric cancer (GC) development. Therefore, the mechanism of IM has been the focus of basic and clinical research. Helicobacter pylori (H. pylori) infection has been recognized as the main pathogenesis of gastric IM. However, more and more studies have shown that chronic inflammation of gastric mucosa caused by bile reflux is the key pathogenic factor of gastric IM. Bile reflux activates the expression of IM biomarkers via the bile acid receptor. In addition, microRNAs, exosomes, and epigenetics are also involved in the occurrence and development of bile acid-induced gastric IM. Currently, the relevant research is still very few. The molecular mechanism of the phenotypic transformation of gastrointestinal epithelial cells induced by bile acids has not been fully understood. This article mainly reviews the physiology and pathology of bile acid, mechanism of gastric IM induced by bile acid, bile acid receptors, and so on, in order to provide reference for further research.

Histological features of the gastric mucosa in children with primary bile reflux gastritis

BACKGROUND

Bile reflux is one of the primary factors involved in the pathogenesis of gastric mucosal lesions in patients with chronic gastritis; however, little is known about the exact histological features of bile reflux and its contributions to gastric mucosal lesions in this disease, especially in children with primary bile reflux gastritis (BRG). The aim of this study was to investigate the classic histological changes of the gastric mucosa in children with primary BRG.

METHODS

The Bilitec 2000 was used for 24 h monitoring of gastric bile in 59 children with upper gastrointestinal symptoms. The histological characteristics of the gastric mucosa were examined and scored.

RESULTS

Thirteen of the 59 patients had a helicobacter pylori infection and were excluded; therefore, 46 cases were included in this study. The positive rate of pathological duodenogastric reflux was significantly higher in patients with foveolar hyperplasia than those without foveolar hyperplasia; however, the rate was significantly lower in patients with vascular congestion than those without vascular congestion. The longest reflux time and the total percentage time of bile reflux were significantly lower in patients with vascular congestion than those without vascular congestion. A total of 9 types of histological changes were analyzed using a binary logistic regression. Foveolar hyperplasia and vascular congestion in the superficial layer became significant variables in the last step of the stepwise regression.

CONCLUSIONS

Foveolar hyperplasia was associated with the severity of bile reflux, suggesting that it is a histological feature of primary BRG in children, while vascular congestion may be a protective factor.

Gastric reddish streaks in the intact stomach: endoscopic feature of reactive gastropathy

The pathogenesis of reddish streaks in the intact stomach is unclear. Sixty-three functional dyspeptic patients with gastric reddish streaks were recruited for the study. Fifty-five patients (group I) had only reddish streaks while nine patients (group II) had additional lesions such as reddish patches or spots randomly scattered throughout the stomach. Updated Sydney system and parameters of reactive gastropathy were used to score the biopsy specimens from reddish streaks separately. Helicobacter pylori infection rate was found to be markedly lower in group I than group II patients (13% vs 89%, P < 0.001). H. pylori-infected patients had higher scores for acute and chronic inflammation (P < 0.001) and foveolar hyperplasia (P < 0.005) than non-infected patients, while other parameters for gastritis and gastropathy were similar between infected and non-infected patients. In H. pylori-non-infected patients all biopsy specimens had at least one histological feature of reactive gastropathy. Bile reflux was observed in 54% of patients (34/63). Only 7.9% used non-steroidal anti-inflammatory drugs and 4.9% drank alcohol. The present data indicate that the fundamental histological features of gastric reddish streaks are reactive gastropathy with low H. pylori infection, and are probably enterogastric reflux related in etiology. Coincidental H. pylori infection increased acute and chronic inflammatory cell infiltration, and enhanced the grade of foveolar hyperplasia.

Gallstones increase the prevalence of Barrett's esophagus

PURPOSE

Bile and acid exposures are thought to be major risk factors for Barrett's esophagus in Western countries. The association of gallstones with Barrett's esophagus has not been fully evaluated. The present study was designed as a case-control study for determining the possible factors associated with endoscopically suspected esophageal metaplasia (ESEM), defined as an endoscopic finding suggestive of Barrett's esophagus, in Japanese patients.

METHODS

A total of 528 patients with ESEM were allocated to the case group, while 528 age- and gender-matched patients without ESEM were allocated to the control group. Findings on esophagogastroduodenoscopy and clinical background factors were compared using a multivariate logistic regression model.

RESULTS

The presence of gallstones and hiatus hernia and the severity of gastric mucosal atrophy were independently associated with the presence of ESEM [odds ratio (OR) 1.67, 95% confidence interval (CI) 1.03-2.69; OR 2.75, 95% CI 1.75-4.33; OR 1.25, 95% CI 1.01-5.6, respectively]. Compared with subjects with neither gastric corpus atrophy nor gallstones, although subjects with gallstones alone were not associated with the presence of ESEM (OR 1.59, 95% CI 0.87-2.92), having both gastric corpus atrophy and gallstones was strongly associated with the presence of ESEM (OR 2.94, 95% CI 1.40-6.17).

CONCLUSIONS

The presence of gallstones was independently associated with the presence of ESEM in the Japanese outpatient population, suggesting a causal association of distal esophageal bile exposure with the development of ESEM. Further studies are needed to confirm our findings in cases with histologically confirmed Barrett's esophagus.

The Role of Cyclooxygenase-2 in Mediating the Effects of Histamine on Cell Proliferation and Vascular Endothelial Growth Factor Production in Colorectal Cancer

PURPOSE

Activity of histidine decarboxylase, the key enzyme in the synthesis of histamine, has been shown to be increased in several types of human tumors. We attempted to establish whether the possible involvement of histidine decarboxylase and histamine in colorectal carcinogenesis might be mediated by the activation of the cyclooxygenase-2 (COX-2) pathway.

EXPERIMENTAL DESIGN

Expression/activity of histidine decarboxylase, histamine content, and prostaglandin E2 (PGE2) production were analyzed in 33 colorectal cancer samples and in the HT29, Caco-2, and HCT116 colon cancer cell lines. The effects of histamine, celecoxib, and H1, H2, and H4 receptor antagonists on COX-2 expression/activity, cell proliferation, and vascular endothelial growth factor (VEGF) production were assessed in the three colon cancer lines that showed different constitutive COX-2 expression.

RESULTS

We showed the up-regulation of histidine decarboxylase protein expression and activity in the tumor specimens when compared with normal colonic mucosa. Histidine decarboxylase activity and histamine content were also significantly higher in metastatic tumors than in nonmetastatic ones. These variables significantly correlated with tumor PGE(2) production. The administration of histamine increased COX-2 expression/activity, cell proliferation, and VEGF production in the COX-2-positive HT29 and Caco-2 cells. Treatment with either H2/H4 receptor antagonists or celecoxib prevented these effects. Histamine had no effect on both the COX-2 pathway and VEGF production in the COX-2-negative HCT116 cells.

CONCLUSIONS

Our data showed that histamine exerts both a proproliferative and a proangiogenic effect via H2/H4 receptor activation. These effects are likely to be mediated by increasing COX-2-related PGE2 production in COX-2-expressing colon cancer cells.

A proinflammatory peptide from Helicobacter pylori activates monocytes to induce lymphocyte dysfunction and apoptosis

Infection with Helicobacter pylori causes chronic gastritis, which is characterized by a dense mucosal infiltration by inflammatory cells such as monocytes/macrophages. H. pylori-induced inflammation is a risk factor for the development of gastric adenocarcinoma, but the mechanisms involved in H. pylori-associated carcinogenesis are poorly understood. A cecropin-like H. pylori peptide, Hp(2-20), was found to be a monocyte chemoattractant and activated the monocyte NADPH-oxidase to produce oxygen radicals. The receptors mediating monocyte activation were identified as FPRL1 and the monocyte-specific orphan receptor FPRL2. Hp(2-20)-activated monocytes inhibited lymphocytes with antitumor properties, such as CD56+ natural killer (NK) cells and CD3epsilon+ T cells. The changes observed in NK cells and T cells--a reduced antitumor cytotoxicity, downregulation of CD3zeta expression, and apoptosis--were mediated by Hp(2-20)-induced oxygen radicals. Histamine, a gastric mucosal constituent, rescued NK cells and T cells from inhibition and apoptosis by suppressing Hp(2-20)-induced oxygen radical formation. We conclude that H. pylori expression of this monocyte-activating peptide contributes to its ability to attract and activate monocytes and reduces the function and viability of antineoplastic lymphocytes. These novel mechanisms may be subject to local, histaminergic regulation in the gastric mucosa.

Analysis of the optical properties of bile

Invasive bile determination is very useful in the diagnosis of many gastric pathologies. At the moment, this measurement is performed with Bilitec 2000, an optical fiber sensor, that is based on absorption by bilirubin. Nevertheless, erroneous evaluations are possible, due to the different configurations which the bilirubin molecule can adopt. The optical behavior of human samples of pure bile and bile+gastric juice has been examined using an optical fiber spectrophotometer and two suitably modified Bilitec 2000 units. A protocol has been established for the treatment of biological fluids, in order to make it possible to study the behavior of their optical properties as a function of pH and concentration without causing any alteration in the samples. The analysis of pH dependence evidenced the presence of different calibration curves at different pH values: the self-aggregation of the bilirubin molecules observed in pure bile samples was almost totally absent in the gastric samples. Measurements carried out on Bilitec 2000 showed that the most appropriate wavelength for bilirubin detection in the stomach should be 470 nm.

Duodenogastric reflux: clinical and therapeutic aspects

BACKGROUND

Duodenogastric reflux is believed to cause damage to gastric mucosa. Most reports on this disorder concern adult patients.

PATIENTS AND METHODS

1120 children with abdominal pain were studied; endoscopic features of duodenogastric reflux were found in 92 patients. To confirm the diagnosis of duodenogastric reflux, cholescintigraphy (Tc99-HEPIDA) was performed. Children with confirmed duodenogastric reflux by scintigraphy were given a prokinetic drug (cisapride).

RESULTS

Endoscopic features of duodenogastric reflux were found in 92 children; the diagnosis was confirmed by scintigraphy in 59 patients. There was no significant difference in the severity of inflammation in gastric mucosa compared with the control group, whereas significantly fewer of these patients were infected with Helicobacter pylori. There was no correlation between regions of isotope accumulation and inflammatory lesions in the stomach. The prokinetic drug (cisapride) helped eliminate or greatly reduce duodenogastric reflux in children.

CONCLUSIONS

When endoscopic features of duodenogastric reflux are found the final diagnosis should be based on an examination that does not itself influence the motility of the gastrointestinal tract: cholescintigraphy seems to be a useful method. However, because the use of milk as a test meal affects the scintigraphic image, there was no correlation between the area of isotope accumulation and the localisation of inflammatory lesions in the stomach. Duodenogastric reflux seems to be less important as a cause of inflammatory lesions than other factors (such as genetic predisposition, stress, etc). Prokinetic drugs have a beneficial influence on treatment results in children with inflammatory lesions of gastric mucosa with duodenogastric reflux.

Gastrin stimulates gastric mast cells in rabbits

In a previous study we demonstrated that in human gastric mucosa tryptase was localized only in mast cells and that its levels were correlated with serum gastrin, suggesting a link between gastrin action and mucosal mast cell function. The aim of the present study was to discover whether pentagastrin injection could stimulate gastric mucosal mast cells in rabbits. Ten female rabbits (group S) were injected s.c. with pentagastrin (10 mu g/kg); another group of ten animals (group C) was injected s.c. with an equal volume of saline solution. One hour after the injection the rabbits were sacrificed and their stomachs removed. Antrum (A), corpus (C) and fundus (F) mucosal homogenates were assayed for total protein, tryptase, pepsinogen A (PGA), histamine and gastrin. Histamine tissue levels were significantly lower in group S than in group C in the antrum (Mann-Whitney test: U = 82, P < 0.01) and in the corpus (U = 83, P < 0.005). Tryptase levels were significantly higher in group S than in group C in all gastric areas (antrum: U = 95, P < 0.001; corpus: U = 85, P < 0.005 and fundus: U = 75, P < 0.05). Total protein, PGA and gastrin did not vary significantly between groups. In group C, no significant correlations were found among the five parameters. In group S, corpus tryptase was correlated with fundus tryptase (Spearman's r = 0.831, P < 0.01). The same relationship was observed for histamine (r = 0.672, P < 0.05). In group S, antrum gastrin was inversely correlated with antrum tryptase (r = -0.903, P < 0.001), and with corpus PGA (r = -0.806, P < 0.05). This study demonstrates that bolus pentagastrin administration stimulates gastric mucosal mast cells in the rabbit.

Gastric mucosal histamine storing cells. Evidence for different roles of mast cells and enterochromaffin-like cells in humans

Gastric mucosal histamine content, enterochromaffin-like cell density, and mast cell density were studied in 13 subjects under omeprazole therapy, 13 partially gastrectomized subjects with a Billroth II reconstruction, 10 partially gastrectomized subjects with a Roux-en-Y reconstruction, and 9 control subjects. Histamine content was significantly greater both in the subjects with higher gastrinemic levels (omeprazole-treated subjects) and those with more abundant enterogastric reflux (Billroth II subjects) than in controls. Enterochromaffin-like cell density was significantly greater in the omeprazole subjects than in each of the other groups. Mast cell density was significantly greater in Billroth II subjects than in controls. Serum gastrin levels, mucosal histamine content, and enterochromaffin-like cell density were positively correlated. Gastrin was not correlated to mast cell density. These results support the existence of different control pathways for enterochromaffin-like and mast cells. Moreover, they suggest that enterochromaffin-like cells and mast cells are involved in the regulation of gastric secretion and in gastric mucosal injury-repair mechanisms, respectively, due to histamine release.

Helicobacter pylori potentiates histamine release from rat serosal mast cells induced by bile acids

In the present study we have experimentally addressed the effects of Helicobacter pylori on the bile acid capability of histamine release. Bile acids alone were confirmed to be able to induce in vitro histamine release from rat serosal and mucosal mast cells. On the contrary, no significant histamine release was obtained when incubating any Helicobacter pylori preparations alone with mast cells. However, histamine release induced by bile acids was significantly enhanced, without any significant increase in lactate dehydrogenase activity, when whole washed or formalin-killed bacterial cells or crude cell walls were incubated with mast cells in the presence of cholic (0.3 mM), deoxycholic (0.3 mM), or lithocholic (0.3 mM) acids, chenodeoxycholylglycine (0.3 mM), and deoxycholyltaurine (3 mM). The electron microscopic features of mast cells incubated with Helicobacter pylori were consistent with an exocytotic secretion. The release of histamine induced by 0.3 mM deoxycholic acid in the presence of Helicobacter pylori was inhibited by the preincubation of the cells with dimaprit (an H2 agonist) and potentiated by the H2 antagonist, ranitidine. The current results suggest a link between human Helicobacter pylori infection and histamine release and a possible involvement of gastric mucosal mast cells in the pathogenesis of Helicobacter pylori-associated gastritis.