In vitro models of the liver fail to precisely recapitulate the complex structures of hepatic lobules, which consist of diverse cell types in which hepatocytes develop and function. However, the development of light-assisted 3D bioprinting has enabled the design of digital masks that allow distinct cell types to be assembled in precise tissue architecture.

Researchers used such a method to build a 3D triculture model of the human liver in which hepatic progenitor cells derived from human induced pluripotent stem cell (hiPSC) are localized to hexagonal lobules within a photopolymerizable gel matrix using one mask, followed by localization of two types of supporting cells to the surrounding spaces using a second mask.

The hiPSC-derived hepatic progenitor cells (hiPSC-HPCs) grown in 3D triculture expressed hepatic markers at higher levels than those grown in either 2D triculture or 3D hiPSC-HPC monoculture, suggesting that 3D triculture enabled greater hepatocyte maturation than the two other methods.

Cells grown in 3D triculture also secreted relatively greater amounts of albumin and urea and expressed higher levels of key cytochrome P450 enzymes, which metabolize drugs in the liver.

According to the authors, the triculture model has potential applications for personalized medicine, drug screening, and translational studies.

http://www.pnas.org/content/early/2016/02/04/1524510113