Potential impact of Helicobacter pylori-related metabolic syndrome on upper and lower gastrointestinal tract oncogenesis

Both Helicobacter pylori infection and metabolic syndrome present significant global public health burdens. Metabolic syndrome is closely related to insulin resistance, the major underlying mechanism responsible for metabolic abnormalities, and Helicobacter pylori infection has been proposed to be a contributing factor. There is growing evidence for a potential association between Helicobacter pylori infection and insulin resistance, metabolic syndrome and related morbidity, including abdominal obesity, type 2 diabetes mellitus, dyslipidemia, hypertension, all of which increase mortality related to cardio-cerebrovascular disease, neurodegenerative disorders, nonalcoholic fatty liver disease and malignancies. More specifically, insulin resistance, metabolic syndrome and hyperinsulinemia have been associated with upper and lower gastrointestinal tract oncogenesis. Apart from cardio-cerebrovascular, degenerative diseases and nonalcoholic fatty liver disease, a number of studies claim that Helicobacter pylori infection is implicated in metabolic syndrome-related Barrett's esophagus and esophageal adenocarcinoma development, gastric and duodenal ulcers and gastric oncogenesis as well as lower gastrointestinal tract oncogenesis. This review summarizes evidence on the potential impact of Helicobacter pylori-related metabolic syndrome on gastroesophageal reflux disease-Barrett's esophagus-esophageal adenocarcinoma, gastric atrophy-intestinal metaplasia-dysplasia-gastric cancer and colorectal adenoma-dysplasia-colorectal cancer sequences. Helicobacter pylori eradication might inhibit these oncogenic processes, and thus further studies are warranted.

A potential impact of Helicobacter pylori-related galectin-3 in neurodegeneration

Neurodegeneration represents a component of the central nervous system (CNS) diseases pathogenesis, either as a disability primary source in the frame of prototype neurodegenerative disorders, or as a secondary effect, following inflammation, hypoxia or neurotoxicity. Galectins are members of the lectin superfamily, a group of endogenous glycan-binding proteins, able to interact with glycosylated receptors expressed by several immune cell types. Glycan-lectin interactions play critical roles in the living systems by involving and mediating a variety of biologically important normal and pathological processes, including cell-cell signaling shaping cell communication, proliferation and migration, immune responses and fertilization, host-pathogen interactions and diseases such as neurodegenerative disorders and tumors. This review focuses in the role of Galectin-3 in shaping responses of the immune system against microbial agents, and concretely, Helicobacter pylori (Hp), thereby potentiating effect of the microbe in areas distant from the ordinary site of colonization, like the CNS. We hereby postulate that gastrointestinal Hp alterations in terms of immune cell functional phenotype, cytokine and chemokine secretion, may trigger systemic responses, thereby conferring implications for remote processes susceptible in immunity disequilibrium, namely, the CNS inflammation and/or neurodegeneration.

Site- and grade-specific diversity of LINE1 methylation pattern in gastroenteropancreatic neuroendocrine tumours

BACKGROUND

Recent data indicate that gastroenteropancreatic neuroendocrine tumours (GEP-NETs) have a hypomethylated long interspersed element (LINE1) promoter. To answer the question, of whether LINE1 may be of value in assessing the malignant potential of GEP-NETs, we analysed LINE1 methylation in different organs.

MATERIALS AND METHODS

A total of 58 GEP-NETs of gastric (n=14), pancreatic (n=15), small intestine (n=17), appendix (n=8), colorectal (n=4) and non-neoplastic tissues were analysed using DNA isolation, bisulphite-treatment and pyrosequencing.

RESULTS

LINE1 hypomethylation was detected in 50% of gastric, 100% pancreatic, 82% small intestine, 87.5% appendix and 100% colorectal NETs. G1 (p<0.001) and G2 (p<0.05) colorectal, and G1 (p<0.001) and G2 (p<0.001) pancreatic NETs exhibited significant LINE1 hypomethylation compared with non-neoplastic tissues. Higher rates of LINE1 hypomethylation in G2 pancreatic NETs than in G1 NETs (p<0.05) were observed. NETs exhibited a significantly lower frequency of hypomethylation in cases with lymph node metastases (p<0.05).

CONCLUSION

LINE1 hypomethylation may serve as a marker of tumour grade and lymph node metastasis.