Hypergastrinemia

Gastrin activates autophagy and increases migration and survival of gastric adenocarcinoma cells

BACKGROUND

The peptide hormone gastrin exerts a growth-promoting effect in both normal and malignant gastrointestinal tissue. Gastrin mediates its effect via the cholecystokinin 2 receptor (CCKBR/CCK2R). Although a substantial part of the gastric adenocarcinomas express gastrin and CCKBR, the role of gastrin in tumor development is not completely understood. Autophagy has been implicated in mechanisms governing cytoprotection, tumor growth, and contributes to chemoresistance. This study explores the role of autophagy in response to gastrin in gastric adenocarcinoma cell lines.

METHODS

Immunoblotting, survival assays and the xCELLigence system were used to study gastrin induced autophagy. Chemical inhibitors of autophagy were utilized to assess the role of this process in the regulation of cellular responses induced by gastrin. Further, knockdown studies using siRNA and immunoblotting were performed to explore the signaling pathways that activate autophagy in response to gastrin treatment.

RESULTS

We demonstrate that gastrin increases the expression of the autophagy markers MAP1LC3B-II and SQSTM1 in gastric adenocarcinoma cells. Gastrin induces autophagy via activation of the STK11-PRKAA2-ULK1 and that this signaling pathway is involved in increased migration and cell survival. Furthermore, gastrin mediated increase in survival of cells treated with cisplatin is partially dependent on induced autophagy.

CONCLUSION

This study reveals a novel role of gastrin in the regulation of autophagy. It also opens up new avenues in the treatment of gastric cancer by targeting CCKBR mediated signaling and/or autophagy in combination with conventional cytostatic drugs.

Insights into gastric neuroendocrine tumors burden

Type 1 gastric neuroendocrine tumors (gNETs) are usually small lesions, restricted to mucosal and sub-mucosal layers of corpus and fundus, with low aggressive behavior, for the majority of cases. Nevertheless, some cases present aggressive behavior. The increasing incidence of gNETs brings together a new relevant problem: how to identify potentially aggressive type 1 gNETs. The challenging problem seems to be finding out signs or features able to predict potentially aggressive cases, allowing a tailored approach, since the involved societies dedicated to provide guidelines for management of these neoplasms apparently failed in producing staging systems able to accurately predict prognosis of these tumors. Additionally, it is also important to try to find out explanations for increasing incidence, as well as to identify potential targets aiming to reach better control of this neoplasia. Here, we discuss potential pathways implicated in aggressive behavior, as well as new strategies to improve clinical management of these tumors.

Hemorrhage from Extra-Antral Gastric Antral Vascular Ectasia in a Patient with Duodenal Heterotopic Gastric Mucosa

Gastric antral vascular ectasias (GAVE) have been increasingly recognized as an uncommon cause of chronic gastrointestinal bleeding and anemia, although their underlying pathogenesis is not completely well understood. Heterotopic gastric mucosa (HGM) has been reported to occur at various sites along the gastrointestinal tract and although relatively common, it is often asymptomatic. We report a case of a 60-year-old woman with a prior history of GAVE who developed melena and symptomatic anemia during her hospitalization following cardiac catheterization. Initial EGD demonstrated nonbleeding antral GAVE and a newly discovered duodenal mass. Duodenal mass biopsies were ultimately notable for HGM along with histologic features of extra-antral GAVE. The patient required blood transfusions and consequently had a small bowel endoscopy notable for fresh blood in the proximal small bowel. The patient underwent a small bowel push enteroscopy which demonstrated active bleeding of the duodenal mass and overlying oozing GAVE, which was cauterized with Argon-Plasma Coagulation with adequate hemostasis. We present for the first time a novel association between GAVE and HGM. Our case illustrates that extra-antral GAVE may occur with HGM in the duodenum. We explore potential mechanisms by which HGM may be involved in the pathogenesis of GAVE.

Adverse reactions and rational use of proton pump inhibitors

Proton pump inhibitors (PPIs) are a class of important drugs for treating acid related diseases, such as gastroesophageal reflux diseases (GERD), peptic ulcer, Zollinger-Ellison syndrome, and upper gastrointestinal bleeding. When combined with other drugs, PPIs can be used for the eradication of Helicobacter pylori. Short-term use of PPIs can cause allergic reactions, adverse reactions of the hematologic system, the digestive system and the nervous system and so on. Long-term use of PPIs can cause a series of new safety issues, such as increased risk of infection, vitamin B₁₂ deficiency caused by the lack of nutrients, fractures, hypomagnesemia, occurrence or development of atrophic gastritis, interstitial nephritis, microscopic colitis, increased risk of serious skin allergy and so on. However, inappropriate use and off-label use of PPIs, and even abuse of PPIs are very common worldwide. Therefore, clinical rational use of PPIs should be emphasized among the relevant national administration departments, clinicians and pharmacists.

Metabolic and histopathological effects of sleeve gastrectomy and gastric plication: an experimental rodent model

Introduction

Obesity has recently become a major health problem, and researchers have been directed to work toward the development of surgical techniques, with new mediators playing an important role in nutrition. Gastric plication (GP) and sleeve gastrectomy (SG) have become popular recently. These are widely used techniques in bariatric surgery.

Objectives

In this study, we aimed to compare the efficiency of SG and GP techniques on rats.

Methods

Wistar-Hannover rats (n=18) were divided into three equal groups, namely SG, GP, and control. Blood samples were taken before the operation and on the 30th day after the operation. The weights of all rats were recorded both on first day and the 30th day after the operation. Serum gastrin, ghrelin, and leptin levels were also measured on the same days. For histopathological examination, gastrectomy was performed after the animals were sacrificed.

Results

Average weight loss was 10% for the SG group and 6.5% for the GP group. One month after the operations, the decrease in the ghrelin and leptin levels of GP and SG groups was significant compared with the levels of the control group. Gastrin levels of the SG group increased significantly compared with those of the control group. Histopathological examination revealed that there was significant decrease in the ghrelin and leptin levels of the GP and SG groups compared with those of the control group. Foveolar hyperplasia (FH), cystic glandular dilatation, and fibrosis were significantly higher in the GP and SG groups compared with the control group.

Conclusion

Although GP is not as effective as SG in terms of weight loss, it provides the same effectiveness in decreasing ghrelin and leptin levels. Histopathological findings revealed that FH, fibrosis, and the cystic glandular dilatation development rates were similar.

Neurochemical Plasticity of the Coeliac-Superior Mesenteric Ganglion Complex Neurons Projecting to the Prepyloric Area of the Porcine Stomach following Hyperacidity

This study was designed to determine neurochemical properties of the coeliac-superior mesenteric ganglion (CSMG) neurons supplying the prepyloric area of the porcine stomach in physiological state and following experimentally induced hyperacidity. To localize sympathetic neurons innervating the studied area of stomach, the neuronal retrograde tracer Fast Blue (FB) was applied to control animals and hydrochloric acid infusion (HCl) groups. After 23 days, animals of the HCl group were reintroduced into a state of general anesthesia and intragastrically given 5 mL/kg of body weight of 0.25 M aqueous solution of hydrochloric acid. On the 28th day, all animals were sacrificed. The CSMG complexes were then collected and processed for double-labeling immunofluorescence. In the control animals, FB-positive perikarya displayed immunoreactivity to tyrosine hydroxylase (TH), dopamine β-hydroxylase (DβH), neuropeptide Y (NPY), and galanin (GAL). Experimentally induced gastric hyperacidity changed the neurochemical phenotype of the studied neurons. An upregulated expression of GAL and NPY and the de novo synthesis of neuronal nitric oxide synthase (nNOS) and leu5-enkephalin (LENK) as well as downregulated expression of TH and DβH in the stomach-projecting neurons were observed. These findings enrich existing knowledge about the participation of these active substances in adaptive mechanism(s) of the sympathetic neurons during pathological processes within the gastrointestinal tract.