Luminal Nalpha-methyl histamine stimulates gastric acid secretion in duodenal ulcer patients via releasing gastrin

Evolutionary aspects of gastrointestinal tract microbiome-host interaction underlying gastrointestinal barrier integrity

In the host sustenance and homeostasis, the microbiome is a key component in the functional system. Throughout ontogenetic development, microbiome including that of the gastrointestinal tract (GIT) is the vital factor that ensures not only host functioning, but also its interaction with environment. To uncover the mechanisms underlying GIT microbiome showing a decisive influence on host organism, a systematic approach is needed, because diverse microorganisms are predominantly localized in different parts of the GIT. Recently, a new interdisciplinary direction of science, nanobioinformatics that has been extensively developed considers gene networks as the major object of study representing a coordinated group of genes that functionally account for formation and phenotypic disclosure of various host traits. Here, an important place should be provided to the genetically determined level of the gastrointestinal tract microbiome, its interaction at the level of the host food systems. There have been increasing evidence indicating that the microbiome is directly involved in the pathogenesis of host diseases showing a multi-layered interaction with host metabolic and immune systems. At the same time, the microbial community is unevenly distributed throughout the gastrointestinal tract, and its different portions are variously active while interacting with the host immune system. The architecture of interaction between the microbiome and host cells is extremely complex, and the interaction of individual cells, at the same time, varies greatly. Bacteria colonizing the crypts of the small intestine regulate enterocyte proliferation by affecting DNA replication and gene expression, while bacteria at the tip of the intestinal villi mediate gene expression responsible for metabolism and immune response. Enterocytes and Paneth cells, in turn, regulate the vital activity of the community of microorganisms through the production of polysaccharides (carbohydrates) and antibacterial factors on their surface. Thus, the integrity of the gastrointestinal barrier (GIB) is maintained, which protects the body from infections and inflammation, while violation of its integrity leads to a number of diseases. It has been shown that depending on the dominance of certain types of bacteria the microbiome can maintain or disrupt GIB integrity. The structural and functional GIB integrity is important for body homeostasis. To date, at least 50 proteins have been characterized as being involved in the structural and functional integrability of tight junctions between gastrointestinal tract epithelial cells. The current review comprehensively discusses such issues and presents original research carried out at various facilities of translational biomedicine.

Helicobacter pylori: Perturbation and restoration of gut microbiome

Alternate remedies with natural products provides unlimited opportunities for new drug development. These can be either as pure compounds or as standardized set of compounds. The phytochemicals and secondary metabolites are in great demand for screening bioactive compounds and plays an important role towards drug development. Natural products have many advantages over to synthetic chemical drugs. Helicobacter pylori (H. pylori) a Gram-negative bacteria has been classified as Class I carcinogen by World Health Organization in 1994. Current treatment regimens for H. pylori is ‘triple therapy’ administrated for two weeks which includes a combination of two antibiotics like Amoxicillin and Clarithromycin and a proton pump inhibitor (PPI) like Lansoprazole, and for ‘quadruple therapy’ in addition to antibiotics and a PPI, Bismuth is used. Antibiotic resistance can be named as the main factor for failure of treatment of H. pylori infection. The need of the hour is to develop a herbal remedy that could combat the growth of H. pylori. Probiotics can also be used as ‘feasible’ tool for H. pylori infection management. Present review is an attempt to briefly discuss about the pathogenicity, genetic predisposition, perturbation of gut microbiota due to antibiotic treatment and restoration of healthy gut microbiota with phytochemicals and probiotics.

Factors Related to Upper Gastrointestinal Symptom Generation in 2275 Helicobacter pylori Seroprevalent Adults

BACKGROUND AND AIM

Upper gastrointestinal (UGI) symptoms are common; however, the role of Helicobacter pylori and gastric corpus atrophy in the generation of these symptoms is controversial. The aim of this study was to determine the risk factors for UGI symptoms in adults in an endemic area of H. pylori infection.

METHODS

Korean adults who completed questionnaires on the day of serum anti-H. pylori IgG and pepsinogen (PG) assays before UGI endoscopy were included. Gastric corpus atrophy was based on the criteria of a serum PG I/II ratio <3.0 and a PG I <70 ng/ml.

RESULTS

Of the 2275 included subjects, 723 (31.8%) had at least one UGI symptom. A total of 374 (16.4%) subjects had multiple symptoms without significant correlations between the symptoms (λ < 0.2). The H. pylori serology assay was positive in 1382 (60.7%) subjects, and gastric corpus atrophy was present in 291 (12.8%). Neither H. pylori seropositivity (p = 0.077) nor gastric corpus atrophy (p = 0.138) was related to the presence of UGI symptoms. Female gender and smoking were independent risk factors for heartburn and upper abdominal pain (all p < 0.001). Furthermore, female gender was the only independent risk factor for multiple UGI symptoms (p < 0.001), globus sensation (p < 0.001), early satiety (p < 0.001), epigastric soreness (p = 0.001), and chest discomfort (p = 0.003).

CONCLUSIONS

In an H. pylori seroprevalent population, female gender is the most common risk factor followed by smoking for UGI symptom generation. Neither H. pylori seropositivity nor gastric corpus atrophy is an independent risk factor for UGI symptom generation.

Medicinal plants in the treatment of Helicobacter pylori infections

CONTEXT

Helicobacter pylori is a small, spiral, Gram-negative bacillus that plays a role in the pathogenesis of a number of diseases ranging from asymptomatic gastritis to gastric cancer. Schedule compliance, antibiotic drug resistance, and side-effects of triple or quadruple therapy have led to research for novel candidates from plants.

OBJECTIVE

The purpose of this paper is to review the most potent medicinal plants of recently published literature with anti-H. pylori activity. For centuries, herbals have been used by traditional healers around the world to treat various gastrointestinal tract disorders such as dyspepsia, gastritis, and peptic ulcer disease. The mechanism of action by which these botanicals exert their therapeutic properties has not been completely and clearly elucidated. Anti-H. pylori properties may be one of the possible mechanisms by which gastroprotective herbs treat gastrointestinal tract disorders.

MATERIALS AND METHODS

Electronic databases such as PubMed, Google scholar, EBSCO, and local databases were explored for medicinal plants with anti-H. pylori properties between 1984 and 2013 using key words "medicinal plants" and "Helicobacter pylori" or "anti-Helicobacter pylori".

RESULTS

A total of 43 medicinal plant species belonging to 27 families including Amaryllidaceae, Anacardiaceae, Apiaceae, Apocynaceae, Asclepiadoideae, Asteraceae, Bignoniaceae, Clusiaceae, Chancapiedra, Combretaceae, Cyperaceae, Euphorbiaceae, Fabaceae, Geraniaceae, Lamiaceae, Lauraceae, Lythraceae, Menispermaceae, Myristicaceae, Myrtaceae, Oleaceae, Papaveraceae, Plumbaginaceae, Poaceae, Ranunculaceae, Rosaceae, and Theaceae were studied as herbs with potent anti-H. pylori effects.

CONCLUSION

Traditional folk medicinal use of some of these plants to treat gastric infections is substantiated by the antibacterial activity of their extracts against H. pylori.

Modulating the cytokine response to treat Helicobacter gastritis

The conventional view of gastric acid secretion is that a negative feedback mechanism arises in response to high acidity, such that somatostatin keeps G-cells and parietal cells from producing more gastrin and acid, respectively. When the stomach becomes infected, for example with Helicobacter pylori (H. pylori), the feedback mechanism is impaired. In animal models, our laboratory has demonstrated that other types of bacteria besides H. pylori can cause gastritis. For example, under conditions of low acidity, gastritis is secondary to bacterial overgrowth, not production of excessive acid, thus suggesting a new paradigm for the regulation of gastric acid secretion under inflammatory conditions. Cytokines, released during the gastric inflammatory response, including IFN gamma, TNF alpha and IL-1 beta stimulate the G-cell to produce gastrin. Gastrin in turn triggers the release of acid, and hypergastrinemia suppresses somatostatin, the inhibitor of acid. The overall response results in maximal gastric acid output that acts as the stomach's most important anti-microbial agent. The increased acid secretion by the stomach in the presence of H. pylori seems to be part of the innate immune response, in that gastrin and somatostatin are reciprocally regulated by Th1 or Th2 cytokines, respectively. In a mouse model, we showed that octreotide, a somatostatin, analog, is an efficacious treatment for Helicobacter gastritis. In humans, octreotide might accelerate recovery from H. pylori infection, reducing the duration of antibiotic therapy.

Neuroendocrinology of gastric H+ and duodenal HCO3- secretion: the role of brain-gut axis

Gastric H+ and duodenal HCO3- secretions are precisely regulated by neuro-hormonal mechanisms at central and peripheral levels to match the rate of these secretions with the type of stimulation of sensory receptors in the head area (sight, smell, taste, etc.) and in the gastro-intestinal system. Two-way communication pathways operate between the brain and the gut, each comprising afferent fibers signaling sensory information from the gut to the brain and efferent fibers transmitting signals in opposite direction. Short intramural and long extramural reflexes are triggered as well as various gut hormones are released by feeding that "cooperate" with the "brain-gut axis" in the alteration of exocrine and endocrine gastro-duodenal secretion, motility and blood circulation. The malfunction of gastric or duodenal secretory mechanisms may lead to disturbances of gastric H+-pepsin or duodenal mucus-HCO3- secretion and to gastro-duodenal disorders and diseases. This review presents recent advances in pathophysiological mechanisms underlying gastro-duodenal secretory disorders.