Cadmium uptake is not affected by iron in an experimental model of the neonatal small intestinal epithelium

Abstract

The aim of the present study was to examine if iron (Fe) affects cadmium (Cd) uptake in partially differentiated Caco‐2 cells, as an in vitro model of the neonatal small intestinal epithelium. Caco‐2 cells were allowed to differentiate 7 or 21 days post‐confluency (DPC) in control (CM) or Fe supplemented (FeM) media. At both time points, 109Cd and 59Fe uptake was examined and quantitative gene expressions of DMT1 and DMT1‐IRE measured. DMT1 protein was also localized using an antibody recognizing both DMT1 and DMT1‐IRE. Our results showed that 109Cd uptake was not affected by FeM 7 DPC, whereas a reduction in 109Cd uptake was observed in FeM treated cells 21 DPC. 59Fe uptake showed the same characteristics. FeM neither affected DMT1 gene expression at 7 nor 21 DPC, whereas DMT1‐IRE mRNA was downregulated by FeM at both 7 and 21 DPC. In 7 DPC cells DMT1‐protein only exhibited intracellular localization. However, in 21 DPC cells DMT1 was also detected at the apical membrane. The results obtained in the present study supports the hypothesis that there are developmental differences in the handling of both Cd and Fe in neonates (7 DPC Caco‐2 cells) as compared to adults (21 DPC Caco‐2 cells), which may be related to the function and cellular localization of DMT1. Furthermore, the experimental model used herein constitutes a promising system for more detailed studies concerning these developmental differences.