Liver cells, in particular the parenchymal hepatocytes, are widely used in the laboratory to assess the potential toxicity or efficacy of drugs. Hepatocytes inside the body have a nearly unlimited capacity for replication. When as much as two-thirds of a whole healthy liver is surgically removed, the hepatocytes within the liver remnant undergo rapid and extensive proliferation to restore liver mass completel.
In the other hand, 3D bioprinted human tissues can be constructed with precision from tiny building blocks made of living human cells, using a process that translates tissue-specific geometries and cellular components into 3D designs that can be executed by a device designed by the Californian company Organovo. Once built, the bioprinted tissues share many key features with native tissue, including tissue-like cellular density, presence of multiple cell types, and the development of key architectural and functional features associated with the target native tissue.
This image is a cross-section of bioprinted human liver tissue demonstrating compartmentalization between the hepatocytes (shown as blue nuclei), endothelial cells (red), and hepatic stellate cells (green)
The overall goal is to develop living, multi-cellular human tissues that can be maintained in the laboratory environment for extended periods of time and sampled serially for both functional and histological changes in response to injury, pathogens, or treatments.