Recellularization of organs: what is the future for solid organ transplantation?

Allogeneic organ transplantation is burdened by donor shortage, graft rejection and adverse effects of lifelong immune suppression. Engineering bioartificial organs from acellular organ scaffolds and patient-derived cells are a new approach to potentially overcome these limitations.

Decellularized organs yield a scaffold of extracellular matrix on which cells can adhere, integrate and ultimately form functional tissue. Various cell sources are currently used to repopulate acellular scaffolds, however, all have limitations. Patient-derived pluripotent stem cells hold great promise for tissue and organ engineering, when robust and mature cells can be directed in a reliable and safe manner. Finally, to produce mature organotypic tissue from a nonfunctional seeded scaffold, cellular scaffolds are cultured under biomimetic conditions in vitro. Alternatively, organs may be implanted at an immature stage to harness the recipient's body's regenerative capacity. In proof of principle experiments to date, bioengineered small animal organs have shown rudimentary function and maintained patency for limited time when transplanted in vivo.

Recent advances in bioengineering organs raise the hope that we can overcome organ donor shortage and eliminate the need for livelong immunosuppression. However, significant challenges remain in generating mature large-scale donor-like bioartificial organs.