EFFECTS OF SHEAR-STRESS ON METABOLIC FUNCTION OF THE COCULTURE SYSTEMOF HEPATOCYTE NONPARENCHYMAL CELLS FOR A BIOARTIFICIAL LIVER

To improve the culture conditions of hepatocytes for use as a bioartif icial liver, the effects of shear flow on the co-culture system of hep atocytes/nonparenchymal cells (NPC) were investigated. A flow chamber with a collagen coated rectangular glass plate, where hepatocytes (5 x 10(4) cell/cm(2)) and NPC (2 x 10(5) cell/cm(2)) were seeded, was use d to attain a shear stress of 4.7 dyne/cm(2). Concentrations of ammoni a and urea in the medium were measured daily during the 2 week experim ent. The metabolic activity of hepatocytes in the homotypic culture we re lower than those of the co-culture, especially when the cultivation time exceeded 1 week. In addition, the applied shear flow promoted ac tivity of the co-culture system. An enhancement in the rates of ammoni um removal and urea synthesis was obtained in the perfusion systems. M orphologic observation revealed that aggregates of hepatocytes formed abundantly in the perfusion system and hepatocytes developed a cuboid shape. This suggested that perfusion affected the function and morphol ogy of hepatocytes in the co-culture system. Shear flow could induce c ell-cell interactions and secretion of extracellular matrix through th e activation of NPC.