Pre-coating decellularized liver with HepG2-conditioned medium improves hepatic recellularization

Liver transplantation from compatible donors has been the main therapy available for patients with irreversible hepatic injuries. Due to the increasing shortage of organs suitable for transplantation, tissue engineering technologies are important alternatives or surrogate approaches for the future of human organ transplantations. New bioengineering tools have been designed to produce decellularized organs (i.e. scaffolds) which could be recellularized with human cells. Specifically, there is an unmet need for developing reproducible protocols for inducing better cellular spreading in decellularized liver scaffolds. The aim of the present work was to investigate the possibility to improve liver scaffold recellularization by pre-coating decellularized tissue scaffolds with HepG2-conditioned medium (CM). Furthermore, we evaluated the capability of commercial human liver cells (HepG2) to adhere to several types of extracellular matrices (ECM) as well as CM components. Wistar rat livers were decellularized and analyzed by histology, scanning electron microscopy (SEM), immunohistochemistry and residual DNA-content analysis. Human induced pluripotent stem cells (hiPSCs)-derived mesenchymal cells (hiMSCs), and human commercial hepatic (HepG2) and endothelial (HAEC) cells were used for liver scaffold recellularization with or without CM pre-coating. Recellularization occurred for up to 5 weeks. Hepatic tissues and CM were analyzed by proteomic assays. We show that integrity and anatomical organization of the hepatic ECM were maintained after decellularization, and proteomic analysis suggested that pre-coating with CM enriched the decellularized liver ECM. Pre-coating with HepG2-CM highly improved liver recellularization and revealed the positive effects of liver ECM and CM components association.