Current drug development is usually based on the principle to test new substances in two-dimensional (2D) cell culture and subsequently characterize them in an animal model. This procedure, however, has several drawbacks. Cells in a 2D cell culture do not represent the physiology of cells in a three-dimensional (3D) tissue, as they, for example, differ in their gene expression patterns. Animal models have the disadvantage that the animal cells differ from human cells. In addition, in vivo experiments are usually associated with unethical suffering of the animals.
To solve these problems, 3D organ models are being developed. In these models, cells are cultivated in the natural 3D environment. It is possible to employ human cells, and the use of animal models can be avoided. Great advancements were made with the development of additive manufacturing (3D bioprinting) technologies. The aim of the project is to produce a liver model by 3D printing. The liver is the main organ for the metabolization of exogenous substances. In addition, it is the target of numerous viruses of high medical relevance (e.g. hepatitis B and C viruses and adenoviruses).
In the project, the three-dimensional vascular structure of the liver will be printed and repopulated with human cells. To this end, a liver was explanted from a mouse. For the sake of animal welfare, it was explanted from a mouse that was left over from another animal experiment and was sacrificed anyway, so that no additional animal was needed. The explanted liver was decellularized (Figure 1A) and plastinated (Figure 1B) for spatial digitalization by CT scan (Figure 1C).