The early human trials of recellularized transplants continue to go well: "A 10-year-old British boy has become the first child to undergo a windpipe transplant with an organ crafted from his own stem cells. ... The world's first tissue-engineered windpipe transplant was done in Spain in 2008 but with a shorter graft. Doctors say the boy is doing well and breathing normally. ... In order to build him a new airway, doctors took a donor trachea, stripped it down to the collagen scaffolding, and then injected stem cells taken from his bone marrow. The organ was then implanted in the boy and over the next month, doctors expect the stem cells to transform into specialised cells which form the inside and outside of the trachea. ... more clinical trials were needed to prove the technique worked but that the team was also thinking about transplanting other organs, such as the oesophagus. ... The advantage of the new approach is that it can be performed quickly and cheaply and so if successful it could be made available to large numbers of patients at relatively low cost." The downside of recellularization is that it doesn't eliminate the need for a donor organ - but it does open up the possibility of using animal organs instead of human organs, with no threat of rejection, and it certainly contributes to advancing the state of the art. I expect to see recellularized heart transplants tested in humans within the next few years.