FORMATION OF PORCINE HEPATOCYTE SPHEROIDS FOR USE IN A BIOARTIFICIAL LIVER

Xenogeneic hepatocytes have recently been used in a bioartificial live r device as a potential short-term extracorporeal support of acute liv er failure. Scaling up the system requires large quantities of viable and highly active cells. Hepatocytes grown as spheroids manifest highe r metabolic activities for longer time periods as compared to those in monolayer cultures, Use of hepatocyte spheroids for application in a bioartificial liver can possibly alleviate the need of scaling up. Por cine hepatocytes when cultured under stirred conditions, form multicel lular spheroids in a defined culture medium, Spheroids were formed 24 h after cell inoculation with an efficiency of 80-90% and a mean diame ter of about 135 mu m. Scanning electron microscopy revealed numerous microvilli projecting from the entire surface of the spheroids. Transm ission electron microscopy revealed differentiated hepatocytes which d isplayed well-developed cytoplasmic structures separated by bile canal iculus-like structures. The morphological studies show a resemblance b etween cells in the spheroids and in the liver in vivo. Ureagenesis by spheroids was twice as active and was sustained for a longer culture period than that by hepatocytes cultured as monolayers, Preparation of porcine hepatocyte spheroids in an agitated vessel is simple efficien t and reproducible. It will allow for preparation of large quantities of spheroids to be employed in a bioartificial liver device as well as in liver metabolism studies.