Abstract

3D Bioprinting of Human Hepatic Tissue Models

Hector Martínez, Chief Technology Officer, CELLINK

In this study, we evaluate the bioprintability of human liver ECM under physiological conditions to assess the in vitro biocompatibility with human hepatic cells and to model liver fibrosis in vitro. Human hepatic cell lines (HepG2 and LX2) were gently mixed with HEP X™ bioink using a CELLMIXER® directly into a cartridge before bioprinting. Tissue printing was performed in a BIO X 3D printer under physiological conditions. Bioprinted tissues were maintained in 3D culture up to 14 days and exposed to TGFß1 for 6 days in order to promote an in vitro fibrogenic process. The resultant bioprinted liver tissue was analysed by viability assay, histology and gene and protein expression. The combination of human liver ECM bioink with liver cell types resulted in an increased cell viability and proliferation compared to control bioink. Pro-fibrogenic genes and proteins including aSMA (p<0.001) and pro-COL1 (p<0.001) were up-regulated in the LX2-laden constructs after 6 days of TGFß1 exposure. HepG2-laden constructs showed spontaneous formation of spheroids after 14 days in culture with up-regulation of albumin gene expression and protein secretion after 14 days compared to 7 days (p<0.001). This is the first report describing the bioprinting of human hepatic tissue using human liver ECM as bioink. This is a key advance in the development of cell-instructive bioinks for the study of liver disease and for the development of 3D hepatic tissue for transplantation.