MASSIVE CULTURE OF HUMAN LIVER-CANCER CELLS IN A NEWLY DEVELOPED RADIAL FLOW BIOREACTOR SYSTEM - ULTRAFINE STRUCTURE OF FUNCTIONALLY ENHANCED HEPATOCARCINOMA CELL-LINES

With a view to initiating clinical trials, cell morphology and functio n for a newly developed artificial liver support system employing high ly functional human liver cell line, FLC-7, cultured in a radial flow bioreactor were compared to cells grown in a conventional monolayer cu lture. The radial flow bioreactor consists of a vertically extended cy lindrical matrix comprised of porous glass bead microcarriers through which liquid medium flows from the periphery in toward the central axi s generating a beneficial concentration gradient of oxygen and nutrien ts, while preventing excessive shear stresses or buildup of waste prod ucts. The three-dimensional culture system supports high-density (1.1 x 10(8) cells/ml-matrix), large scale cultures (4.4 x 10(10) cells/400 ml-bioreactor) with long-term viability. Scanning and transmission el ectron microscopy (SEM and TEM) revealed that cells cultured in a mono layer system were flattened and extended with numerous cytoplasmic pro jections. Cells in the three-dimensional culture were spherical and co vered with microvillilike processes resembling liver cells in vivo. Th e cells were solidly attached on the surfaces and within the pores of the microcarriers in highly dense colonies. The spherical cells remain ed in close contact with adjacent cells, while circulation of liquid m edium flowed fi eely through spaces between cells. FLC-7 cells produce d albumin at a rate of 6.41 mu g/24 h/10(6) cells. Alpha-fetoprotein I :AFP) production dropped neatly threefold in comparison to monolayer c ultures. Results demonstrated that the new artificial liver support sy stems (ALSS) provides a superior three-dimensional culture environment that allows cells to perform at naturally functioning levels.