Investigation of in vitro functionality of liver microtissues produced by co-culture of mesenchymal stem cells, endothelial and hepatic cell line

There is an urgent need for reliable in vitro liver models to assess the mechanisms of human diseases, and impact of newly developed drugs or toxins. Previously showed that co-culture of hepatocytes with non-parenchymal cells and presence of extracellular matrix (ECM) improve the in vitro functionality of hepatocytes. Aim of this study was to develop a reproducible method for scalable generation of liver microtissues.

In this experimental study, liver microtissues with 500um diameter generated through co-culturing of Huh-7, human mesenchymal stem cells and human umbilical vein endothelial cells in a composite hydrogel of liver-ECM and alginate. Cell viability, capability for glycogen storage and cytochrome P450 enzyme activity were evaluated on day 28. Hepatic-specific genes (ALB and SULT1A1) on days 1 and 14, and albumin and urea secretion on days 1, 7, 14, 21 and 28 were assessed. Furthermore, the microtissue sensitivity to acute toxicity of Metformin, Diclofenac and ethanol were investigated. Two-dimensional cultured Huh-7 was considered as control group.

Most cells in the microtissues were alive up to day 28, accumulated glycogen and have cytochrome inducibility 7-fold more than the basic activity. In comparison to control, ALB and SULT1A1 genes upregulated (p<0.05) on day 14, also albumin and urea secretion increased (p<0.05), in all sampling time, in microtissues. Furthermore, microtissues have more sensitivity (p<0.05) to some concentrations of the drugs and ethanol, compared to control.

It seems that the liver microtissues may considered as an appropriate and functional in vitro model for liver.