title: Increased intestinal endotoxin absorption during enteric nematode but not protozoal infections through a mast cell-mediated mechanism.
abstract: It is known that hypersensitivity reactions in the gastrointestinal tract, which are primarily mediated by mast cells, are associated with a secretory response of the epithelium and often increased permeability to macromolecules. Studies to date have not examined the effects of hyperpermeability on the absorption of toxic substances normally present in the intestinal lumen such as bacterial LPS. In the present study, we observed that Strongyloides venezuelensis infection in mice decreases the mRNA expression of intestinal epithelial cell junctional molecules (occludin and zonula occludens 1) and increases portal endotoxin levels 4 h after intragastric administration of LPS (20 mg/kg body weight). Furthermore, an increase in the flux of immunoglobulin G into the intestinal lumen was observed 10 days postinfection (PI). An increased rate of LPS absorption was also seen in mice infected with Nippostrongylus brasiliensis on day 14 PI and rats concurrently infected with S. venezuelensis and N. brasiliensis on day 20 PI. On the other hand, infection with Eimeria vermiformis and Eimeria pragensis was not observed to enhance LPS absorption 4 h after intragastric administration of LPS (20 mg/kg body weight), although E. vermiformis infection did inhibit the epithelial cell mRNA expression of zonula occludens 1, but not occludin, on day 9 PI, resulting in a reduced immunoglobulin G flux than that produced by S. venezuelensis infection. Our results suggest that mastocytosis accompanying intestinal nematode infection increases the intestinal absorption of LPS into the portal circulation by suppressing the expression of tight junction molecules.
authors.affiliation: Veterinary Teaching Hospital and Parasitology, Faculty of Agriculture, University of Miyazaki, Gakuen-Kibanadai, Miyazaki, Japan.
authors.forename: Ayman Samir
authors.initials: AS
authors.lastname: Farid
authors.forename: Fumiko
authors.initials: F
authors.lastname: Jimi
authors.forename: Kyoko
authors.initials: K
authors.lastname: Inagaki-Ohara
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Horii
mesh_terms: D000818:Animals; D003048:Coccidiosis / Q000097:blood* / Q000150:complications; D004539:Eimeria; D006967:Hypersensitivity / Q000097:blood / Q000209:etiology; D007408:Intestinal Absorption / Q000187:drug effects; D008070:Lipopolysaccharides / Q000097:blood* / Q000494:pharmacology; D008297:Male; D008407:Mast Cells / Q000378:metabolism*; D008415:Mastocytosis / Q000097:blood* / Q000209:etiology; D008565:Membrane Proteins / Q000096:biosynthesis; D051379:Mice; D009559:Nippostrongylus; D062793:Occludin; D010750:Phosphoproteins / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D017206:Strongylida Infections / Q000097:blood* / Q000150:complications; D013321:Strongyloides; D013322:Strongyloidiasis / Q000097:blood* / Q000150:complications; D019108:Tight Junctions; D013997:Time Factors; D062826:Zonula Occludens-1 Protein
chemical_list: D008070:Lipopolysaccharides; D008565:Membrane Proteins; D062793:Occludin; C568986:Ocln protein, mouse; C568987:Ocln protein, rat; D010750:Phosphoproteins; C569043:Tjp1 protein, mouse; C569044:Tjp1 protein, rat; D062826:Zonula Occludens-1 Protein