Extracorporeal liver support: porcine or human cell based systems?

Initial results of the clinical use of primary porcine liver cells for extracorporeal liver support are being reviewed as the cell source is controversial. According to Eurotransplant data 20-25% of explanted donor livers are not transplanted, due to factors such as steatosis or cirrhosis. This number corresponds to the number of patients with acute liver failure who require bridging therapy to transplantation. Primary human liver cells from transplant discards can be isolated, purified and maintained in bioreactors and provide an alternative for cell-based extracorporeal liver support therapy. A four-compartment bioreactor enables recovery from preservation and isolation injury in a three-dimensional network of interwoven capillary membranes with integrated oxygenation, rendering the liver cells from these discarded donor organs viable for clinical utilization. Patient contact with additional animal-derived biomatrix and fetal calf serum can be avoided. The initiation of an in vitro cultivation phase allows cell stabilization, quality control, and immediate availability of a characterized system without cryopreservation. The hypothesis of this paper is that with appropriate logistics and four-compartment bioreactor technology, cells from human liver transplant discards can serve the demand for cell-based therapy, including extracorporeal liver support.