Fucoidan
Se-Kwon Kim in Marine Biochemistry, 2023
According to the hepatology data, blood clots generated against providing aspirin without fucoidan (Figure 12.2B), showing that the ulcer existed in the stomach tissue. There are no blood clots in the different performances (Figure 12.2A without aspirin and Figure 12.2C with aspirin and fucoidan). It indicates that because fucoidan does not affect the stomach tissue lining, it can prevent gastric ulcers by building a barrier in the mucosa. A thick mucus coating is particularly common on the mucous membrane, synthesized by high cylindrical epithelial cells. The gastric mucosa is a polypeptide with two purposes: it lubricates food masses to facilitate transportation within the stomach and acts as a protective coating on the lining epithelium of the stomach cavity. This protective barrier protects the stomach from being digested by its protein-lysine enzymes. It can migrate from the underlying mucosa into the surface layer according to bicarbonate secretion. The acidity of the mucous layer, or hydrogen ion concentration, is balanced in the vicinity of the epithelium and becomes acidic toward the luminal layer. While gastrointestinal mucus is excluded from the surface epithelium, little pits termed foveolae gastrique can be observed with a magnifying glass (Sinurat & Rosmawaty, 2015).
Fat Digestion and Absorption
Margit Hamosh in Lingual and Gastric Lipases: Their Role in Fat Digestion, 2020
The hydrolysis of fat in the stomach is important not only for the emulsificati m of fat. Its other functions are to promote further fat digestion in the intestine and to provide a rapid energy source in the form of short- and medium-chain fatty acids, which are absorbed directly through the gastric mucosa.51-53 This process is facilitated by the higher rates of release of short- and medium-chain fatty acids from dietary triglycerides (especially those from milk, in which these fatty acids occupy the Sn3 position,58 the preferred site of action of lingual lipase58-60). Short- and medium-chain fatty acids have pKa values of about 4.8 in water;61 however, because they are hydrophylic, they are fairly soluble in both ionized and unionized states.19 These fatty acids are thus able to leave the surface of the oil droplets and are absorbed by passive diffusion through the gastric mucosa in several species,51, 52, 63, 64 including man53 (Figure 3).
Stomach and duodenum
Professor Sir Norman Williams, Professor P. Ronan O’Connell, Professor Andrew W. McCaskie in Bailey & Love's Short Practice of Surgery, 2018
The gastric mucous layer is essential to the integrity of the gastric mucosa. It is a viscid layer of mucopolysaccharides produced by the mucus-producing cells of the stomach and the pyloric glands. Gastric mucus is an important physiological barrier to protect the gastric mucosa from mechanical damage, and also the effects of acid and pepsin. Its considerable buffering capacity is enhanced by the presence of bicarbonate ions within the mucus. Many factors can lead to the breakdown of this gastric mucous barrier. These include bile, non-steroidal anti-inflammatory drugs (NSAIDs), alcohol, trauma and shock. Tonometry studies have shown that, of the entire gastrointestinal tract, the stomach is the most sensitive to ischaemia following a hypovolaemic insult and also the slowest to recover. This may explain the high incidence of stress ulceration in the stomach.
Formononetin inhibits inflammation and promotes gastric mucosal angiogenesis in gastric ulcer rats through regulating NF-κB signaling pathway
Published in Journal of Receptors and Signal Transduction, 2022
Lanjie Yi, Yan Lu, Shun Yu, Qian Cheng, Lanjuan Yi
The gastric mucosa is a thin and fragile mucosal tissue that exists on the inner wall of the stomach, like a natural ‘barrier’ to protect the safety of the stomach wall. It has a dynamic balance mechanism of injury and self-repair, which protects the normal operation of the stomach [16]. Gastric ulcer is a localized deep necrotic lesion involving the entire mucosal thickness and muscular mucosa [17]. The healing of gastric ulcer requires the reconstruction of epithelial structure and underlying connective tissue. CD34, a member of cadherin family, is a highly glycosylated i-type transmembrane glycoprotein, which plays an important role in mediating cell adhesion [18]. ZO-1 and occludin are indispensable components of tight junctions regulated by pro-inflammatory cytokines and growth factors [19,20]. Our study shown that formononetin could increase the levels of CD34, tight junction proteins (ZO-1 and occludin) in a dose-dependent manner. The healing of gastric ulcers includes the formation of granulation tissue, contraction of ulcer tissue, angiogenesis and re-epithelialization. Neovasculature and reepithelialization of ulcer wounds play a great role for gastric ulcer healing [9]. Endothelin-1 (ET-1) is an extremely potent vasoconstrictor peptide originally isolated from endothelial cells [21]. Experimental and clinical evidence has demonstrated that VEGF plays a vital role in the formation of choroidal neovascularization and may have a synergistic effect with NO in ulcerative colitis [22,23]. The results of this study also showed that formononetin can promote gastric mucosal angiogenesis in gastric ulcer rats.
Protective effect of valerian extract capsule (VEC) on ethanol- and indomethacin-induced gastric mucosa injury and ameliorative effect of VEC on gastrointestinal motility disorder
Published in Pharmaceutical Biology, 2022
Yuan Feng, Wan Dai, Junyu Ke, Yong Cui, Shuang Li, Jingjing Ma, Wenfeng Guo, Gang Chen, Ning Li, Yanwu Li
Gastrointestinal (GI) diseases, such as peptic ulcer, chronic gastritis, and functional dyspepsia, are highly prevalent and generally considered to be a leading cause of the incidence of several other concomitant diseases. GI mucosal as a barrier plays a pivotal role in the protection of digestive organs and the damage of gastric mucosa is considered the early stage of gastric ulcer (Woolf and Rose 2021). Previous studies reported that gastric mucosa damage is attributable to multiple factors including chemical factors (smoking, drinking, and drugs), physical factors (improper diet), inflammation, intestinal bacterium, and phycological stress (Padol et al. 2012; Haj Kheder et al. 2018; Zhou and Zhang 2019; Woolf and Rose 2021). Among the various reasons contributing to gastric injury, non-steroidal anti-inflammatory drugs (NSAIDs) indomethacin can depress the expression of cyclooxygenases (COXs) and increase the free radical formation and excessive generation of inflammatory mediators, thus inducing gastric mucosal damage or gastric ulcer (Abd EI-Rady et al. 2021). In addition, alcohol is another common risk factor for GI disease. Excessive drinking may cause the appearance of bleeding or stomach ulcers by rupturing the gastric mucosa barrier and inducing inflammatory cell infiltration (Ostaff et al. 2015). Recently, the animal models of gastric injuries induced by indomethacin and ethanol have been widely used to investigate the underlying pathophysiological and evaluate the protective effects of herbal medicines against gastric ulcers and gastritis (Dejban et al. 2020).
Ultra-structural study of the indomethacin-induced apoptosis and autophagy in rat gastric parietal cells
Published in Ultrastructural Pathology, 2020
Sahar M Gebril, Yuko Ito, Eman E. Abu-Dief, Mahmoud Rezk Abdelwahed Hussein, Hoda M Elsayed, Asmaa Naser Mohammad, Usama M Abdelaal, Kazuhide Higuchi
Parietal cells (PCs) are the most predominant cell type in the gastric mucosa. They are responsible for acid secretion, and they are frequent in the isthmus and the neck of the gastric glands.9,10 Ultra-structurally, PCs have unique characteristics such as microvilli lacking the glycocalyx coat, intracellular canaliculi (ICC), numerous large mitochondria and limited protein synthetic apparatus, the rough endoplasmic reticulum (RER), and the Golgi bodies.11 The secretory activity of PCs alternates according to the physiological phases of feeding or fasting.12During fasting the PCs undergo membrane recruitment of ICC membrane into the cytoplasm with the formation of tubulovesicles (tbv) that will be ready to be added to the membrane on activation.13,14 During feeding, PCs have wide ICC with highly folded membrane studded with H +. K+ -ATPase subunits (proton pumps) for active acid formation.15,16