The ins and outs of engineering functional tissues and organs: evaluating the in-vitro and in-situ processes

For many disorders that result in loss of organ function, the only curative treatment is organ transplantation. However, this approach is severely limited by the shortage of donor organs. Tissue engineering has emerged as an alternative solution to this issue. This review discusses the concept of tissue engineering from a technical viewpoint and summarizes the state of the art as well as the current shortcomings, with the aim of identifying the key lessons that we can learn to further advance the engineering of functional tissues and organs.

A plethora of tissue-engineering strategies have been recently developed. Notably, these strategies put different emphases on the in-vitro and in-situ processes (i.e. preimplantation and postimplantation) that take place during tissue formation. Biophysical and biomechanical interactions between the cells and the scaffold/biomaterial play a crucial role in all steps and have started to be exploited to steer tissue regeneration.

Recent works have demonstrated the need to better understand the in-vitro and in-situ processes during tissue formation, in order to regenerate complex, functional organs with desired cellular organization and tissue architecture. A concerted effort from both fundamental and tissue-specific research has the potential to accelerate progress in the field.