Abstract
Cylindrospermopsin (CYN) is a cyanotoxin produced by various cyanobacterial species. It is a water soluble zwitterion, stable at extreme temperatures and pH. Despite the main route of exposure to CYN is through drinking water and food, there is a lack of data concerning its intestinal absorption and the mechanisms implicated. The aim of this study was to characterize the mechanisms involved in the intestinal absorption of CYN, using Caco-2 human cell line as a model of the intestinal epithelium. The results obtained in the present work increases the limited knowledge regarding CYN transport across the intestinal epithelium and identifies the paracellular route as an important pathway in CYN absorption. A minor carrier-mediated transcellular transport has been evidenced. This transport is not affected by low temperatures, suggesting that an active mechanism is not involved. Moreover, the transport through the intestinal monolayer is H+ and GSH dependent and Na+independent. The transport characteristics elucidated in this study prepare the ground for future studies directed at identifying transporters involved in the intestinal absorption of this toxin.