Iron uptake in aluminium overload: in vivo and in vitro studies

In this study we have evaluated the haematological consequences of chronic aluminium (Al) overload. We have also investigated 'in vivo' whether aluminium overload may modulate gastrointestinal iron (Fe) absorption and 'in vitro' whether the presence of aluminium may influence the cellular uptake of iron. The in vivo studies were performed in rats with normal renal function and the in vitro experiments were done using the rat intestinal epithelial cell line RIE-1. The results demonstrate that aluminium deposit in tissues even with normal renal function. The intraperitoneal aluminium loading resulted in serum and tissue aluminium increases comparable with concentrations found in aluminium-intoxicated renal patients. The aluminium intoxication was accompanied by a microcytic anaemia with a haematological pattern similar to that observed in iron-deficiency anaemia. Nevertheless, iron absorption was significantly reduced despite an increased total iron binding capacity (TIBC). In addition, aluminium was also able to reduce in vitro cellular uptake of iron in the RIE-1 intestinal cell line. These experimental results demonstrate that aluminium interferes with iron absorption and iron transfer, and suggest that these mechanisms may be responsible for maintaining and even increasing the anaemia observed in aluminium overload.