Magnesium transport from aqueous solutions across Caco-2 cells - an experimental model for intestinal bioavailability studies. Physiological considerations and recommendations

The Caco-2 cell model is gaining more and more importance as an in vitro me thod to study intestinal nutrient bioavailability from foods. In a previous article we presented evidence that fractional Mg2+ transport from differen t aqueous solutions containing differing amounts of magnesium varies consid erably in some cases. In the present article we discuss the role of electro lytes, such as calcium and the anions HCO3-, SO42- and Cl-, in modulating m agnesium absorption. Another purpose of this manuscript is to give recommen dations, based mainly on physiological knowledge, which can be helpful when planning and conducting intestinal bioavailability studies using either th e Caco-2 culture system or other in vitro models in order to achieve nearly similar conditions as in vivo.