Role of energy metabolism in drug-induced acute gastric mucosal injuries in humans

Multiomics-Based Biocargo Components Analysis in Enterococcus faecium Membrane Vesicles

Enterococcus spp. have been shown to have gastrointestinal tract protective functions; our recent results suggest that membrane vesicles (MVs) play an important role in the gastric protection of Enterococcus faecium (E. faecium). The specific function is determined by molecular compositions of MVs. To resolve biocargo components in E. faecium MVs (EfmMVs), MVs were isolated from E. faecium culture. Transcriptomics, label-free quantitative proteomics, and untargeted metabolomics were performed to obtain information about the complexity of ribonucleic acids (RNAs), proteins, and metabolites biocargo they carry, respectively. RNA-sequencing identified a total of 2122 transcripts. The top 20 transcripts accounted for 27.63% of total counts, which, including enzymes, participate in glycolysis, ribosomal proteins, DNA-directed RNA polymerases, protein-synthesizing relative enzymes, molecules associated with protein post-translational processing and transport, and peptidoglycan lyases. Label-free quantitative proteomics analysis identified a total of 711 proteins. The top 20 proteins accounted for 48.02% of all identified proteins, which including ribosomal proteins, enzymes participate in glycolysis, DNA-directed RNA polymerases, protein-synthesizing relative enzymes, peptidoglycan lyases, and autolysin. Untargeted metabolomics analysis identified a total of 519 metabolites. The top 20 metabolites accounted for 79.55% of all identified metabolites, which included amino acids, substrates, or products in the metabolism of amino acids, natural organic acids, products in the metabolism of organic acids, ketone compounds, and two other compounds. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses indicated that the identified biocargo components enriched in metabolism, genetic, and environmental information processing. Overall, we hope that the current exploration of multiple "-omics" analyses of this EfmMVs will provide useful information and further groundwork for future studies on E. faecium application.

Risk factors for bleeding esophagogastric varices

Bleeding from gastric varices (GVs) is generally considered more severe than that from esophageal varices (EVs) but occurs less frequently. We review the risk factors for bleeding EVs and GVs. GVs were divided into 2 groups: cardiac varices (CVs, Lg-c) and fundal varices (FVs), i.e., varices involving the fundus alone (Lg-f) or varices involving both the cardia and fundus (Lg-cf). Elevated pressure in the portal vein is a risk factor for bleeding EVs. The portal pressure in patients with GVs and a gastrorenal shunt is lower than that in patients with EVs. The large size of varices is a risk factor for bleeding EVs. Red color signs are elevated red areas that are important for predicting the risk of variceal bleeding, and red wale markings, dilated venules oriented longitudinally on the mucosal surface, have been considered to be the sign with the highest risk. Red color signs are rare in FVs, possibly because of the pronounced thickness of the mucosal layer. Bleeding EVs are not associated with use of antiulcer drugs or nonsteroidal anti-inflammatory drugs (NSAIDs). Although, in patients with bleeding GVs, "occasional" use of an oral NSAID is an important step leading to variceal hemorrhage, especially from FVs, even if the mucosa is protected by antiulcer drugs. Constipation, vomiting, severe coughing, and excessive consumption of alcohol may precipitate rupture of EVs.

Antibacterial and anti-atrophic effects of a highly soluble, acid stable UDCA formula in Helicobacter pylori-induced gastritis

Helicobacter pylori is one of the main causes of atrophic gastritis and gastric carcinogenesis. Gastritis can also occur in the absence of H. pylori as a result of bile reflux suggesting the eradication of H. pylori by bile acids. However, the bile salts are unable to eradicate H. pylori due to their low solubility and instability at acidic pH. This study examined the effect of a highly soluble and acid stable ursodeoxycholic acid (UDCA) formula on H. pylori-induced atrophic gastritis. The H. pylori infection decreased the body weight, mitochondrial membrane potential and ATP level in vivo. Surprisingly, H. pylori-induced expression of malate dehydrogenase (MDH), a key enzyme in the tricarboxylic acid cycle, at both the protein and mRNA levels. However, the UDCA formula repressed MDH expression and increased the membrane potential thereby increasing the ATP level and body weight in vivo. Moreover, UDCA scavenged the reactive oxygen species (ROS), increased the membrane potential, and inhibited apoptosis in AGS cells exposed to H(2)O(2) in vitro through the mitochondria-mediated pathway. Taken together, UDCA decreases the MDH and ROS levels, which can prevent apoptosis in H. pylori-induced gastritis.

Membrane-bound, ATP-dependent energy systems and tissue hypoxia in human gastric mucosa

1. The biochemical measurements of gastric mucosal ATP, ADP, AMP and cAMP offer excellent information on the extent of tissue oxygenation, when the observations are taken simultaneously from the same tissue sample. 2. Adenosine triphosphate is split by membrane-bound enzymes in two directions (to ADP and cAMP), while ADP and cAMP transform to AMP, supplying further energy liberation. 3. The liberated free energy modifies physiologically or pathophysiologically the functions of target organ cells. 4. Different drugs, hormones and mediators, have different effects on the regulation of ATP breakdown (into ADP vs cAMP). 5. The actual tissue level of ATP is a consequence of the equilibrium between the directions of ATP-ADP and ATP-cAMP breakdown, as well as of ATP resynthesis. 6. The biochemical measurement of the reduction in gastric mucosal ATP alone is not enough proof for the existence of tissue hypoxia, because demonstration of the simultaneous elevation of tissue lactate is also necessary.