克服胃肠道粘液屏障:依赖调节粘酶活性

The gastric glands contain parietal cells that secrete hydrochloric acid (HCl) for digestion. The cells secrete HCl because it is highly corrosive and essential for breaking down food. To achieve this, they secrete hydrogen and chloride ions into the lumen of the gastric glands, which combine to form HCl.
Within parietal cells, carbonic acid is first formed through the reaction of water and carbon dioxide. The dissociation of carbonic acid releases bicarbonate and hydrogen ions. The bicarbonate...

Peptic ulcer disease, commonly called PUD, represents a multifaceted condition characterized by disruptions in the lining of the gastrointestinal (GI)  tract. Central to the protection of the gastrointestinal lining is the mucosal-bicarbonate barrier. This physiological defense mechanism is a formidable shield against the corrosive effects of gastric acid and pepsin secretion in the stomach. Its role is pivotal in maintaining the structural integrity of the stomach's inner lining.

In the intricate landscape of the gastric lumen, excessive acid secretion disrupts the natural defense mechanisms, weakening the mucus-bicarbonate barrier. This vulnerability allows pepsin to infiltrate epithelial cells, digesting mucosal proteins and triggering erosion, leading to ulcer formation.
In this scenario, mucosal protective agents like sucralfate play an essential role. Sucralfate, a complex of sulfated sucrose and aluminum hydroxide, demonstrates its usefulness in acidic conditions,...

Peptic ulcers, often induced by H. pylori infections or NSAID usage, arise from disruptions in the delicate balance of gastric acid production. Peptic ulcers stem from heightened gastric acid levels due to H. pylori infections or NSAID use. The protective mucus layer diminishes in the presence of these factors, allowing gastric acid to erode the stomach lining and form ulcers.
Gastric acid, a potent cocktail of hydrogen and chloride ions, is produced in specialized parietal cells within the...

The gastric mucosa produces prostaglandins E2 (PGE2) and prostacyclin (PGI2), crucial in maintaining gastric health. They exert cytoprotective effects, including increasing bicarbonate secretion, releasing protective mucin, reducing gastric acid output, and preventing harmful vasoconstriction. These effects are mediated through various receptors, such as EP1, EP2, EP3, and EP4.
Non-steroidal anti-inflammatory drugs (NSAIDs) can induce peptic ulcers by inhibiting cyclooxygenase, decreasing...

The skin and mucous membranes serve as the primary line of defense against pathogens by providing both physical and chemical protection. These barriers are essential in preventing the entry and establishment of microbes, thereby maintaining the integrity of the host.
The outer layer of the skin, the epidermis, is a robust barrier comprising layers of closely packed keratinized cells. This dense arrangement prevents microbes from penetrating the body. The periodic shedding of epidermal cells...