Iron absorption by CaCo 2 cells cultivated in serum‐free medium as in vitro model of the human intestinal epithelial barrier

Abstract

A cell culture system consisting of confluent monolayer of human enterocyte-like CaCo 2 cells, cultivated in a serum-free nutritive medium, on microporous synthetic membranes has been used as an in vitro model of the intestinal epithelial barrier. The uptake of 55ferric citrate, as well as the transepithelial passage from the apical to the basolateral pole, have been studied. CaCo 2 cells accumulate iron in a time- and concentration-dependent process, largely specific from the apical pole. When 55ferric citrate is added at the apical pole, radioiron appears at the basal pole and the clearance rate is approximately four times higher than in the opposite direction; the amounts of 55Fe increase with the concentration in iron citrate and the duration of incubation. At least two concurrent mechanisms could be involved in iron absorption across monolayers of CaCo 2 cells. A first route would correspond to a paracellular passage of the metal from the apical to the basal pole. The second route would involve a selective intake of iron at the apical pole and could require a reduction of ferric iron, prior to the entry. Iron accumulated by the cells would, for a minor part, be stored within ferritin, whereas the major part would be excreted at the basolateral pole, either as low molecular weight material of undetermined chemical composition but from which iron is easily mobilized by apotransferrin or associated with neosynthesized apotransferrin. Vesicular transport and protein synthesis seem to be required.

Role of two recently cloned rat liver GSH transporters in the ubiquitous transport of GSH in mammalian cells.

“…HepG2 cells are derived from a human hepatoblastoma and retain many of the differentiated features of mature hepatocytes (9). CaCo-2 cells are derived from a human colon carcinoma and have been a useful model for the study of intestinal epithelial function (10)(11)(12)(13). MDCK cells are derived from distal tubular cells of a canine kidney which exhibit polarized functions (14,15), Cos-1 cells, derived from kidney of a monkey, exhibit fibroblast-like characteristics, and HeLa cells are derived from a human cervical carcinoma.…”

Synthesis and evaluation of RGD peptidomimetics aimed at surface bioderivatization of polymer substrates

“…4,6 In our laboratory, we use microporous membranes obtained by a track-etching process which allows the preparation of capillary-pore' membranes 57 with very uniform, nearly perfectly round cylindrical pores. Such membranes are made from homogeneous 10±20 mm thick polymer ®lm precursors in two steps, consisting of bombardment with heavy ions (Ar +9 ) accelerated in a cyclotron, followed by immersion into an appropriate solution of reagents which preferentially etches the tracks, leading to the creation of pores.…”

“…The aqueous phase was extracted with ethyl acetate (4Â150 mL). The organic phases were dried over MgSO 4 …”

“…The mixture was vigorously shaked during 72 h (fresh catalyst was added three times). After ®ltration and concentration, the residue was dissolved in CHCl 3 , dried over MgSO 4 and concentrated under vacuum. The residue was dissolved in CF 3 CO 2 H (2 mL) and left for 2.5 h at 20 C. After evaporation, the residue was dissolved in water and extracted with CHCl 3 .…”

Effects of Amino Acids and Dipeptides on the Uptake and Transport of Iron by Caco-2 Cells Cultured in Serum-Free Medium.

“…The quantity of iron taken up by cells was calculated from the specific radioactivity of the test solution and is presented as pmol/insert (Halleux & Schneider, 1994;Han et a/, 1995). showed that the iron uptake increased by more than 50% when the molar ratio of Fe3+ : NTA was decreased from I : 2 to I : 1.…”