• Bio-chemical cues
• Chemotactic ability
• Clinical therapies
• Native micro-environment
• Non-immune biomaterials and grafts
• Tissue-inks

• R01 EB020640 NIBIB NIH HHS
• R01 EB030060 NIBIB NIH HHS

Liver transplantation is the only curative therapy for end stage liver disease, but is limited by the organ shortage, and is associated with the adverse consequences of immunosuppression. Repopulation of decellularised whole organ scaffolds with appropriate cells of recipient origin offers a theoretically attractive solution, allowing reliable and timely organ sourcing without the need for immunosuppression. Decellularisation methodologies vary widely but seek to address the conflicting objectives of removing the cellular component of tissues whilst keeping the 3D structure of the extra-cellular matrix intact, as well as retaining the instructive cell fate determining biochemicals contained therein. Liver scaffold recellularisation has progressed from small rodent in vitro studies to large animal in vivo perfusion models, using a wide range of cell types including primary cells, cell lines, foetal stem cells, and induced pluripotent stem cells. Within these models, a limited but measurable degree of physiologically significant hepatocyte function has been reported with demonstrable ammonia metabolism in vivo. Biliary repopulation and function have been restricted by challenges relating to the culture and propagations of cholangiocytes, though advances in organoid culture may help address this. Hepatic vasculature repopulation has enabled sustainable blood perfusion in vivo, but with cell types that would limit clinical applications, and which have not been shown to have the specific functions of liver sinusoidal endothelial cells. Minority cell groups such as Kupffer cells and stellate cells have not been repopulated. Bioengineering by repopulation of decellularised scaffolds has significantly progressed, but there remain significant experimental challenges to be addressed before therapeutic applications may be envisaged.

• Regenerative
• Bioengineering
• Scaffolds
• Liver
• Decellularisation
• Recellularisation

• chemical hepatotoxicity
• in vitro
• organoids
• rat
• toxicologic pathologist

• Decellularization
• Extracellular matrix
• Liver engineering
• Organ engineering

• Biomaterials
• Extracellular matrix
• Liver tissue engineering
• Liver transplantation
• Regenerative medicine
• Whole organ decellularization

The burden of liver diseases continues to grow worldwide, and liver transplantation is the only option for patients with end-stage liver disease. This procedure is limited by critical issues, including the low availability of donor organs; thus, novel therapeutic strategies are greatly needed. Recently, bioengineering approaches using decellularized liver scaffolds have been proposed as a novel strategy to overcome these challenges. The aim of this systematic literature review was to identify the major advances in the field of bioengineering using decellularized liver scaffolds and to identify obstacles and challenges for clinical application. The main findings of the articles and each contribution for technique optimization were highlighted, including the protocols of perfusion and decellularization, duration, demonstration of quality control—scaffold acellularity, matrix composition, and preservation of growth factors—and tissue functionality after recellularization. In previous years, many advances have been made as this technique has evolved from studies in animal models to human livers. As the field develops and this promising technique has become much more feasible, many challenges remain, including the selection of appropriate cell types for recellularization, route of cell administration, cell-seeding protocol, and scalability that must be standardized prior to clinical application.

• Articular cartilage
• Cartilage repair
• Chondrogenesis
• Decellularization
• Devitalization
• Elastic cartilage
• Extracellular cartilage matrix
• Fibrocartilage
• Mesenchymal stromal cells
• Recellularization

This protocol describes the generation of a three-dimensional (3D) ex vivo liver model and its application to the study and development of viral vector systems. The model is obtained by repopulating the extracellular matrix of a decellularized rat liver with a human hepatocyte cell line. The model permits studies in a vascularized 3D cell system, replacing potentially harmful experiments with living animals. Another advantage is the humanized nature of the model, which is closer to human physiology than animal models.

In this study, we demonstrate the transduction of this liver model with a viral vector derived from adeno-associated viruses (AAV vector). The perfusion circuit that supplies the 3D liver model with media provides an easy means to apply the vector. The system permits monitoring of the major metabolic parameters of the liver. For final analysis, tissue samples can be taken to determine the extent of recellularization by histological techniques. Distribution of the virus vector and expression of the delivered transgene can be analyzed by quantitative PCR (qPCR), Western blotting and immunohistochemistry. Numerous applications of the vector model in basic research and in the development of gene therapeutic applications can be envisioned, including the development of novel antiviral therapeutics, cancer research, and the study of viral vectors and their potential side effects.