Bioreactors for Liver Tissue Engineering

A cute liver failure (ALF) patients have a high risk of mortality. The elective treatment for ALF still is orthotopic liver transplantation. Donor organ scarcity and the associated high costs make transplantation possible for only about one third of the patients on the transplantation waiting list. Engineering a biological liver substitute is an interesting alternative to the traditional ALF therapy. Cells seeded in three-dimensional scaffolds made of bioresorbable biomaterials might be implanted in vivo to replace part of, or the whole, liver and integrate with time. Twoor three-dimensional nonimplantable constructs may be used ex vivo for the EC support of ALF patients until a tissue compatible organ is available or the patient’s own liver heals. Non-implantable three-dimensional constructs may be also useful to investigate liver cell metabolism or as an alternative to animal tests for drug screening or toxicity assessment in vitro. Over the years, research has mainly focused on the development of new culture techniques or new immortalized hepatic cell lines. A major obstacle to the generation of functional substitutes is the limited understanding of the role of specific physicalchemical parameters on tissue development. Bioreactors provide controlled environmental conditions to improve the quality of tissue and to study liver cell metabolism. This review focuses on the bioreactors that have been proposed to develop enhanced biological liver substitutes or study liver cell metabolism.