For a nonhuman donor organ to function adequately in a human host, it must be anatomically similar (so as to allow for surgical implantation), function well in the human setting and not be rejected. (Graft rejection is a risk all transplant recipients face, however it is particularly challenging when the donor organ originates from a nonhuman source.)
We will know relatively soon whether the audacious operation restores Bennett’s health. While his recovery is uncertain and perhaps even a long shot, what is certain is that the door to using bioengineered nonhuman organs has been opened — and with it, the promise of an almost unlimited supply of donor organs could follow. While the road ahead is surely filled with new physiological, technical and even ethical challenges, we may one day look at this courageous procedure the way we now look at Dr. Christaan Barnard’s first heart transplant.