Extracorporeal liver assist devices (ELAD) combine liver epithelial cells with hollow fiber polymer membranes. One of the two major competing versions of ELAD uses malignant cells lacking many liver specific phenotypic traits, particularly detoxification pathways. The other provides a population of freshly isolated porcine hepatocytes (with other contaminant cells) that require constant quality control measures. Ideal ELAD cells should offer both exquisite ammonia metabolism and excellent P450 activity. MultiCell Associates has developed a proprietary cell line (HepLiu), from normal adult porcine hepatocytes. These cells display hepatocyte markers, are non-tumorigenic, retain P45O activity, are both easily propagated in culture and amenable to fast delivery due to their excellent cryogenic characteristics. The long term goal of this proposal is the commercialization of the HepLiu cell line for liver support. This project creates a new cell line, HepLiu GS, through the stable integration of the glutamine synthetase (GS) gene into the HepLiu genome to confer ammonia metabolizing activity in addition to their ability to detoxify benzodiazepine-like substances. As modified, HepLiu GS will become a potent biological agent to treat hepatic coma. The phase II continuation of this project entails a comprehensive plan of characterization, testing and scale up to prepare the HepLiu GS cell line for worldwide commercialization. PROPOSED COMMERCIAL APPLICATIONS: Whole liver transplantation is the only treatment available to treat acute liver failure patients but inavailability of transplantable organs annually results in the deaths of nearly 2000 patients awaiting transplant. Current liver support to extend the viable waiting period of these patients is based on fresh porcine hepatocytes. As a cost effective alternative to these cells, MCA proposes to use a proprietary porcine cell line in liver assist devices. The United States LAD market targeted by MCA represents $875 million annually and world wide may be as high as $2 billion.