Tissue engineering of human biliary epithelial cells on polyglycolic acid / polycaprolactone scaffolds maintains long-term phenotypic stability

The biliary tree is the target of damage in a number of important liver diseases. Although human biliary epithelial cells (hBECs) can be maintained in vitro for up to 8 weeks, using double-collagen gels, which offer a substantial improvement compared with conventional tissue culture plastic, such gels are unstable and, being only semisolid, they do not lend themselves readily to routine analysis. In this study we have investigated the behavior of primary hBECs on polyglycolic acid (PGA) fiber mesh scaffolds. Experiments showed that PGA fiber mesh scaffolds collapsed after 3 or 4 weeks; hence, in order to improve the integrity of the construct, we also developed a polycaprolactone (PCL)-stabilized PGA scaffold. Cells formed spheroidal aggregates while continuing to proliferate long term and expressing phenotypic stability. Aggregates spontaneously detached from the fibers and could either be left to attach to tissue culture plastic, after which cells spread out and continued to proliferate, or they could be reseeded onto fresh constructs, which then became recolonized and the same pattern of tissue formation was repeated. This behavior was observed even after 6 months and is of major significance because this culture model could therefore be used as a long-term strategy for growing, expanding, and exploiting hBECs for subsequent studies of bile duct morphogenesis and tissue engineering of artificial bile ducts.