Colony-forming capacity of porcine liver epithelial cells in culture.

Previously, we reported the presence of certain nonparenchymal epithelial cells (NPECs) in adult porcine livers that demonstrate differentiation patterns including an emergence of duct-like structures (DLSs) in the colonies. In the present study, we examined the effect of supplements to the NAIR-1 medium (Dulbecco modified Eagle medium [DMEM]-F12 containing 5% fetal bovine serum [FBS] and 11 supplements) used in these cultures on formation of DLSs-emerged colonies (type I colonies). No type I colonies were observed in the cultures of the nonparenchymal cell fraction when Roswell Park Memorial Institute-1640 medium or DMEM-F12 (1:1) supplemented with 5% FBS was used as the culture medium. NAIR-1 medium without each component did not produce any significant results. No type I colonies were formed when epidermal growth factor, and hydrocortisone and insulin mixture (A) or nicotinamide and l-ascorbic acid phosphate magnesium salt (Asc2P) mixture (B) was added to the DMEM-F12 medium supplemented with 5% FBS. However, when a combination of A and B was added, colonies were formed at a significant level. Together, the number of type I colonies was increased in the combination of A and B containing a higher concentration of Asc2P. We conclude that NPECs need a mixture of Asc2P and other components as supplements for type 1 colony formation.