Helicobacter pylori infection associates with a mucosal downregulation of ghrelin, negative regulator of Th1-cell responses

Ghrelin regulating liver activity and its potential effects on liver fibrosis and Echinococcosis

Ghrelin widely exists in the central nervous system and peripheral organs, and has biological activities such as maintaining energy homeostasis, regulating lipid metabolism, cell proliferation, immune response, gastrointestinal physiological activities, cognition, memory, circadian rhythm and reward effects. In many benign liver diseases, it may play a hepatoprotective role against steatosis, chronic inflammation, oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress and apoptosis, and improve liver cell autophagy and immune response to improve disease progression. However, the role of Ghrelin in liver Echinococcosis is currently unclear. This review systematically summarizes the molecular mechanisms by which Ghrelin regulates liver growth metabolism, immune-inflammation, fibrogenesis, proliferation and apoptosis, as well as its protective effects in liver fibrosis diseases, and further proposes the role of Ghrelin in liver Echinococcosis infection. During the infectious process, it may promote the parasitism and survival of parasites on the host by improving the immune-inflammatory microenvironment and fibrosis state, thereby accelerating disease progression. However, there is currently a lack of targeted in vitro and in vivo experimental evidence for this viewpoint.

Gastric organoids: Advancing the study of H. pylori pathogenesis and inflammation

For decades, traditional in vitro and in vivo models used for the study of Helicobacter pylori infection have relied heavily on the use of gastric cancer cell lines and rodents. Major challenges faced by these methods have been the inability to study cancer initiation in already cancerous cell lines, and the difficulty in translating results obtained in animal models due to genetic differences. These challenges have prevented a thorough understanding of the pathogenesis of disease and slowed the development of cancer therapies and a suitable vaccine against the pathogen. In recent years, the development of gastric organoids has provided great advantages over the traditional in vivo and in vitro models due to their similarities to the human stomach in vivo, their ease of use, and the capacity for long-term culture. This review discusses the advantages and limitations of existing in vivo and in vitro models of H. pylori infection, and how gastric organoids have been applied to study H. pylori pathogenesis, with a focus on how the pathogen interacts with the gastric epithelium, inflammatory processes, epithelial repair, and cancer initiation. The potential applications of organoids to address more complex questions on the role of hormones, vaccine-induced immunity are also discussed.

Changes in ghrelin, substance P and vasoactive intestinal peptide levels in the gastroduodenal mucosa of patients with morbid obesity

AIMS

The aim of the study was to assess changes in levels of substance P (SP), vasoactive intestinal peptide (VIP) and ghrelin in the gastroduodenal mucosa of obese individuals, which has not been studied before.

METHODS

Forty-six patients with a body mass index (BMI) of >40 kg/m² and 20 patients with a BMI of 18-25 kg/m² were included in the study. VIP and SP levels in the fundus, antrum and duodenal mucosa were measured in freshly frozen tissues using enzyme-linked immunosorbent assay (ELISA). Fasting levels of ghrelin in blood were also measured with ELISA. Tissue levels of ghrelin were assessed by immunohistochemical staining, and immunoreactivity scores were used for ghrelin evaluation in tissues.

RESULTS

Antrum SP levels were higher in the obese group than in the control group. A significant number of obese patients had low VIP levels in the fundus and antrum. Intense ghrelin staining was observed in a limited number of cells in the mucosal area of the gastric fundus that was similar in the control and patient groups. In the antrum and duodenum, ghrelin staining was low in all the samples examined.

CONCLUSION

Here, we found that SP levels are increased, while VIP levels are decreased in the antrum of morbidly obese individuals. Previous studies show that SP increases gastroduodenal motility, that VIP slows it down, and that the gastric emptying rate is higher in obese individuals, preventing negative feedback mechanisms upon food intake. Therefore, increases in SP and decreases in VIP levels in the antrum may contribute to obesity by accelerating gastric emptying.

Population screening and treatment of Helicobacter pylori infection

Helicobacter pylori is an important human pathogen, associated with a substantial burden from both malignant and non-malignant diseases. The bacterium is classed as a human carcinogen, being strongly linked with gastric cancer, the third most common cause of cancer death worldwide and is also associated with common conditions such as dyspepsia and peptic ulcer. Eradication of H. pylori reduces the incidence of gastric cancer and peptic ulcer, as well as the prevalence and costs of managing dyspepsia. Economic analyses suggest that eradication of H. pylori as a means of controlling gastric cancer is cost-effective in high-risk populations. Even in populations at low risk of gastric cancer, there might be other benefits arising from screening and treatment, owing to the effects on non-malignant upper gastrointestinal diseases. However, public health authorities have been slow to consider the benefits of population-based screening and treatment as a means of reducing the morbidity and mortality associated with the infection. There are also concerns about widespread use of eradication therapy, including antimicrobial resistance and a rise in the prevalence of diseases that are negatively associated with H. pylori, such as GERD, Barrett oesophagus, asthma and obesity. This Review summarizes these issues.

The Role of H. pylori CagA in Regulating Hormones of Functional Dyspepsia Patients

Helicobacter pylori (H. pylori, Hp) colonizes the stomachs of approximately 20%–80% of humans throughout the world. The Word Healthy Organization (WHO) classified H. pylori as a group 1 carcinogenic factor in 1994. Recently, an increasing number of studies has shown an association between H. pylori infection and various extragastric diseases. Functional dyspepsia (FD) is considered a biopsychosocial disorder with multifactorial pathogenesis, and studies have shown that infection with CagA-positive H. pylori strains could explain some of the symptoms of functional dyspepsia. Moreover, CagA-positive H. pylori strains have been shown to affect the secretion of several hormones, including 5-HT, ghrelin, dopamine, and gastrin, and altered levels of these hormones might be the cause of the psychological disorders of functional dyspepsia patients. This review describes the mutual effects of H. pylori and hormones in functional dyspepsia and provides new insight into the pathogenesis of functional dyspepsia.

Impact of Helicobacter pylori infection on serum and gastric tissue nucleobindin 2/nesfatin-1 levels

AIM: To investigate the impact of Helicobacter pylori (H. pylori) infection on serum and gastric tissue levels of nucleobindin2 (NUCB2)/nesfatin-1 in humans.

METHODS: Serum and mucosal samples were collected from 83 asymptomatic volunteers who received gastroscopy and had H. pylori infection confirmed by ¹³C breath test, rapid urease test and Warth-Starry staining. The subjects were divided into an H. pylori positive group and an H. pylori negative group. Serum NUCB2/nesfatin-1 concentration was measured by enzyme-linked immunosorbent assay (ELISA) and the expression of NUCB2 mRNA in gastric mucosa was detected by real-time quantitative polymerase chain reaction.

RESULTS: Serum NUCB2/nesfatin-1 concentrations in the H. pylori positive and negative groups did not differ significantly (2.298 ng/mL ± 0.275 ng/mL vs 2.267 ng/mL ± 0.201 ng/mL, P > 0.05). The expression level of NUCB2 mRNA in the H. pylori positive group was significantly higher than that in the H. pylori negative group (1.336 ± 0.324 vs 0.914 ± 0.171, P < 0.01).

CONCLUSION: H. pylori infection induces the upregulation of NUCB2 mRNA in the gastric mucosa, but has no effect on serum NUCB2/nesfatin-1 concentration.

Ghrelin receptor modulates T helper cells during intestinal inflammation

BACKGROUND

The orexigenic peptide ghrelin has anti-inflammatory properties in colitis, however, the mechanism of action and the immune cells targeted remain still to be elucidated. Here, we assessed the possible effect of ghrelin on T helper (Th) cells in a T cell transfer model of chronic colitis.

METHODS

Disease was induced in the recombination activating gene 1 knockout mice (Rag1(-/-) ) by adoptive transfer of naïve Th cells from ghrelin receptor knockout mice (GRLN-R(-/-) ) or littermate wild-type (WT) mice. The course and severity of colitis was assessed by monitoring body weight, diarrhea score, histological analysis, gene expression, and flow cytometry analysis. The possible effects of ghrelin on Th cell proliferation, polarization, and apoptosis was examined in vitro.

KEY RESULTS

Our data showed that Rag1(-/-) mice injected with GRLN-R(-/-) Th cells displayed increased severity of colitis compared to mice injected with WT Th cells. In addition, Rag1(-/-) mice injected with GRLN-R(-/-) Th cells had significantly higher intestinal inflammation and increased accumulation of Th1 and Th17 cells in the colon. In vitro, ghrelin directly affected proliferation of Th cells and induced apoptosis whereas it did not influence Th cell polarization.

CONCLUSION & INFERENCES

Our observations suggest that ghrelin modulates Th effector cells in the gut controlling proliferation and inducing apoptosis. Our findings further support the use of ghrelin as a novel therapeutic option to treat intestinal inflammatory diseases.

Immunity, inflammation, and vaccines for Helicobacter pylori

Helicobacter pylori colonizes mucosa, activates Toll-like and Nod-like receptors, and usually elicits a gastric T-helper 1/17 (Th1/Th17) type of immune response. Among several bacterial factors, the secreted peptidyl prolyl cis, trans-isomerase of H. pylori represents a key factor driving Th17 inflammation. A complex and fascinating balance between H. pylori and host factors takes part in the gastric niche and is responsible for the chronicity of the infection. Novel insights into the innate and adaptive responses against H. pylori, dealing with gastric epithelial cells, cytokines, and immune evasion have been elucidated over the past year and are discussed for the development of an effective vaccine.

Impairment of ghrelin synthesis in Helicobacter pylori-colonized stomach: New clues for the pathogenesis of H. pylori-related gastric inflammation

Ghrelin, the ligand of growth hormone secretagogue receptor 1a, takes part in several functions of the digestive system, including regulation of appetite, energy homeostasis, gastric acid secretion and motility. Ghrelin has also immunoregulatory properties and is supposed to inhibit some inflammatory pathways that can mediate gastric damage. Interestingly, ghrelin synthesis is reduced in the gastric mucosa of patients with Helicobacter pylori (H. pylori) infection, a worldwide condition inducing a T helper (Th)1/Th17 cell response-driven gastritis, which may evolve towards gastric atrophy and cancer. In this article, we review the available data on the expression of ghrelin in H. pylori infection and discuss how the defective ghrelin synthesis may contribute to sustain the ongoing inflammatory response in this disease.