Title of article :
Labile complexes facilitate cadmium uptake by Caco-2 cells Original Research Article
Author/Authors :
L. Verheyen، نويسنده , , F. Degryse، نويسنده , , T. Niewold، نويسنده , , E. Smolders، نويسنده ,
Issue Information :
دوهفته نامه با شماره پیاپی سال 2012
Pages :
10
From page :
90
To page :
99
Abstract :
The Free Ion Activity Model (FIAM) predicts that metal uptake in biota is related to the free ion activity in the external solution and that metal complexes do not contribute. However, studies with plants have shown that labile metal complexes enhance metal bioavailability when the uptake is rate-limited by transport of the free ion in solution to the uptake site. Here, the role of labile complexes of Cd on metal bioavailability was assessed using Caco-2 cells, the cell model for intestinal absorption. At low Cd2 + concentration (1 nM), the CdCln2 − n complexes contributed to the uptake almost to the same extent as the free ion. At large Cd2+ concentration (10 μM), the contribution of the complexes was much smaller. At constant Cd2+ concentration, Cd intake in the cells from solutions containing synthetic ligands such as EDTA increased as the dissociation rate of the cadmium complexes increased, and correlated well with the Cd diffusion flux in solution measured with the Diffusive Gradient in Thin Films technique (DGT). The Cd intake fluxes in the cells were well predicted assuming that the specific uptake is limited by diffusion of the free Cd2+ ion to the cell surface. Our results underline that speciation of Cd has a major effect on its uptake by intestinal cells, but the availability is not simply related to the free ion concentration. Labile complexes of Cd enhance metal bioavailability in these cells, likely by alleviating diffusive limitations.
Keywords :
FIAM , Complexes , Metal uptake , Speciation , Caco-2 cells
Journal title :
Science of the Total Environment
Serial Year :
2012
Journal title :
Science of the Total Environment
Record number :
989512
Link To Document :
بازگشت