Highly polarized primary urothelial cells from human ureter grown as spheroid-like vesicles

Epithelial cells growing in vitro are frequently non-polarized and lack histophysiological characteristics. Furthermore, the quality of two-dimensional cell layers is limited by the physico-chemical properties of the support. Therefore, for an in vitro system to reflect the normal epithelial physiology, it is necessary to maintain the inner and outer geometrical configuration of the cells. In order to avoid the disadvantages of two-dimensional cultures we have established an in vitro model that closely resembles the in vivo situation. Human ureteral epithelial cells (HUEC) were used to prepare multicellular vesicles which maintain a geometrically intact cell organization that is not achieved in conventional cultures. Light and electron microscopy investigations showed the morphology of the cells to be similar to that in situ. HUEC vesicles are more in vivo-like than two-dimensional cultures and therefore represent a suitable model for a variety of research purposes including studies on the pathogenesis of micro-organisms.