Microbial antigens and endotoxins (LPS/PAMPs)

Microbial antigens and endotoxins in the gut lumen are a heterogeneous group of molecules, primarily pathogen-associated molecular patterns (PAMPs) such as lipopolysaccharides (LPS), flagellin, and peptidoglycans, derived from the resident intestinal microbiota (NCBI, 2023). These molecules serve as potent triggers for the innate immune system, primarily through the activation of Toll-like receptors (TLRs) on intestinal epithelial cells and systemic immune cells (PubMed, 2022). In healthy individuals, the intestinal mucosal barrier effectively sequesters these antigens within the lumen; however, barrier dysfunction—often termed "leaky gut"—allows for their translocation into the portal circulation, leading to systemic inflammation (StatPearls, 2023). This translocation is a key driver in the progression of chronic inflammatory diseases, including nonalcoholic steatohepatitis (NASH), cirrhosis, and chronic kidney disease (CKD) (NIH, 2021). Therapeutic interventions targeting these luminal components include oral adsorbents like AST-120, which sequester endotoxins to prevent absorption, and enzymatic agents like alkaline phosphatase that neutralize the toxic lipid A moiety of LPS (Journal of Hepatology, 2020). Additionally, oral immunoglobulins are utilized to bind and neutralize these microbial products, thereby reducing the inflammatory burden on the host (Clinical and Experimental Gastroenterology, 2014).

Other names

EndotoxinsLipopolysaccharidesGut-derived PAMPsMicrobial-associated molecular patternsMAMPsBacterial endotoxinsIntestinal microbial products

Sequestration and adsorption of microbial products within the gastrointestinal tract to prevent systemic translocation; enzymatic neutralization of endotoxin toxicity via dephosphorylation; antibody-mediated binding and neutralization of luminal antigens.