MICROENCAPSULATED HUMAN HEPATOMA (HEPG2) CELLS - IN-VITRO GROWTH AND PROTEIN RELEASE

The feasibility of a microencapsulation process ultimately for cell tr ansplantation was investigated by encapsulating human hepatoma (HepG2) cells in hydroxyethyl methacrylate-methyl methacrylate (HEMA-MMA) mem branes through an interfacial precipitation process. Changes in viabil ity and metabolic activity as well as protein secretion by the encapsu lated cells were studied in vitro. When encapsulated at either low or high density (1 or 5 x 10(6) cells/mL, respectively), HepG2 cells reta ined their active metabolic state and/or proliferated during the initi al 1-week period, after which a significant drop in cell viability was obtained. Encapsulation of a biological attachment substrate, Matrige l, along with the cells, however, resulted in rapid proliferation in b oth low and high density capsules with prolonged maintenance of an act ive metabolic state. The secretion of four model proteins (alpha1-acid glycoprotein, alpha1-antitrypsin, haptaglobin and fibrinogen) was dem onstrated during the 2-week study period for the Matrigel encapsulated cells. Furthermore, the encapsulated cells remained responsive to int erleukin 6 (IL6), a physiological stimulator of plasma protein secreti on, as determined by the elevated secretion of haptaglobin in response to IL6 treatment. We conclude that HEMA-MMA capsules, in the presence of an attachment substrate, provide a suitable environment for the gr owth and expression of differentiated functions of encapsulated hepato ma cells. (C) 1993 John Wiley & Sons, Inc.