Construction of three-dimensional liver tissue models by cell accumulation technique and maintaining their metabolic functions for long-term culture without medium change.

Abstract

Three-dimensional (3D) hepatocyte cultures have attracted much attention to obtain high biological functions of hepatocyte for pharmaceutical drug assessment. However, maintaining the high functions for over one month is still a key challenge although many approaches have been reported. In this study, we demonstrate for the first time simple and rapid construction of 3D-hepatocyte constructs by our cell accumulation technique and their high biological functions for one month, without any medium change. The human hepatocyte carcinoma (HepG2) cells were coated with ∼ 7 nm-sized extracellular matrix (ECM) films consisting of fibronectin (FN) and gelatin (G), and then incubated in cell culture insert to construct 3D-tissue constructs for 24 h. The thickness of obtained 3D-HepG2 constructs was easily controlled by altering seeding cell number and the maximum is over 100 μm. When a large volume of culture media was employed, the 3D-constructs showed higher mRNA expression of albumin and some cytochrome P450 (CYP) enzymes as compared to general two-dimensional (2D) culture. Surprisingly, their high cell viabilities (over 80%) and high mRNA expressions were successfully maintained without medium change for at least 27 days. These results demonstrate novel easy and rapid technique to construct 3D-human liver tissue models which can maintain their high functions and viability for 1 month without medium change.