EFFICIENT INDUCTION OF HEPATOCYTE SPHEROIDS IN A SUSPENSION-CULTURE USING A WATER-SOLUBLE SYNTHETIC-POLYMER AS AN ARTIFICIAL MATRIX

The preparation of hepatocyte spheroids by adding a water-soluble synt hetic polymer as an artificial matrix was performed in a cell suspensi on system. Cell-aggregation was promoted without cytotoxicity by addin g Eudragit (a copolymer of methacrylic acid and methylmethacrylate) to the culture medium. Spheroid-like cell aggregates, whose liver functi ons were enhanced, were effectively formed in the presence of 0.1% Eud ragit, independent of the cultural substratum. Moreover, the mass prep aration of spheroids could be achieved with a high production yield by means of a suspension culture in a spinner flask. In this case, the p olymer protected the cells from damage due to agitation. The spheroids induced with Eudragit expressed high liver functions, such as albumin secretion, ammonia removal, and urea synthesis. On histological obser vation, the spheroids showed a well-developed cell adhesion apparatus and bile canaliculi, In addition, a higher calcium ion concentration i n the cells of spheroids was observed compared with in monolayer cells .