1: Eur J Pharm Sci. 2007 Apr;30(5):380-391. Epub 2007 Jan 13. An improved in vitro model of human intestinal follicle-associated epithelium to study nanoparticle transport by M cells. des Rieux A, Fievez V, Theate I, Mast J, Preat V, Schneider YJ. Universite catholique de Louvain, Unite de Pharmacie Galenique, Avenue E. Mounier, 73-20, 1200 Brussels, Belgium; Laboratoire de Biochimie cellulaire, Institut des Sciences de la Vie, Universite catholique de Louvain, Croix du Sud, 5, 1348 Louvain-La-Neuve, Belgium. An alternative in vitro model of human follicle-associated epithelium (FAE) to study nanoparticle transport mechanisms by M cells was developed and characterized. The previous in vitro model of human FAE has been improved by inverting inserts after Caco-2 cell seeding. Raji and M cells were identified only in inverted co-culture cell monolayers by immunohistochemistry, confocal microscopy, and electron microscopy. The M cell conversion rate evaluated by scanning electron microscopy ranged between 15 and 30% of cells. Transport of 200nm carboxylated polystyrene nanoparticles was higher and more reproducible in the inverted model. Nanoparticle transport was temperature-dependent, not affected by the presence of EGTA or by potassium depletion, but inhibited by EIPA or nystatin, suggesting that it occurs most likely by macropinocytosis. The inverted model appears more physiologic, functional and reproducible than the normally oriented model. PMID: 17291730 [PubMed - as supplied by publisher] Related Links Transport of nanoparticles across an in vitro model of the human intestinal follicle associated epithelium. [Eur J Pharm Sci. 2005] PMID:15946828 Identification of cell adhesion molecules in the human follicle-associated epithelium that improve nanoparticle uptake into the Peyer's patches. [J Pharmacol Exp Ther. 2006] PMID:16914557 Helodermin-loaded nanoparticles: Characterization and transport across an in vitro model of the follicle-associated epithelium. [J Control Release. 2007] PMID:17292503 Transport of chitosan microparticles for mucosal vaccine delivery in a human intestinal M-cell model. [J Drug Target. 2002] PMID:12575734 Cell culture modeling of specialized tissue: identification of genes expressed specifically by follicle-associated epithelium of Peyer's patch by expression profiling of Caco-2/Raji co-cultures. [Int Immunol. 2004] PMID:14688064