Hydrogen sulfide: a rescue molecule for mucosal defence and repair

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,...

Sulfur is an essential element in biological systems, contributing to synthesizing key biomolecules, including amino acids such as cysteine and methionine, and cofactors such as coenzyme A and biotin. Microorganisms primarily assimilate sulfur as sulfate (SO₄²⁻) from the environment, which must undergo a series of biochemical transformations before it can be incorporated into cellular components. As sulfate is highly oxidized, it must undergo assimilatory sulfate reduction to become...

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. Bicarbonate,...

Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.

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...

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...