Recellularization is a transplant preparation process that begins by stripping living cells from donor tissue - such as a heart valve, an entire heart, a trachea, and so forth - to leave behind the extracellular matrix as a scaffold. That scaffold is then seeded with the transplant recipient's own cells, which grow throughout its structure to reform the original tissue. This has proven to be an excellent way to prepare transplants that will not trigger immune rejection, even for xenotransplantation between species. In recent years, we've seen a number of successful recellularized transplants in humans:
Recellularization work is becoming more widespread in the laboratory. Numerous groups are now incorporating this strategy into their own research programs, such as the bone tissue engineers I mentioned not so long ago. But today let me point out a group who are working to generate blood vessels via this methodology:
Using adult stem cells, researchers have created functional blood vessels that could one day replace synthetic grafts often required in various vascular bypass surgeries
"It was our idea to create a more biological conduit that would avoid the problems of synthetic grafts and give patients a better alternative," said McIlhenny. "The significant finding is that we can build a blood vessel from donor tissue and an animal's own adult stem cells. Potentially, patients requiring bypass surgery could receive optimized grafts that would reduce their future complications."
Researchers grew rabbit adult stem cells on human vein scaffolds in the laboratory. The team removed all cells from sections of human saphenous veins, which left a tube consisting only of the protein scaffolding that supported the cells. Because the scaffolding contains no cells; there is less risk the immune system will reject it.
Great shortages and delays exist for people who need organ transplants - largely imposed by regulatory bodies and laws that forbid an open market in body parts or paid agreements between donor and recipient. So organs that might otherwise have been used go to the grave, and funds that might have benefited the deceased's next of kin are spent on other things; yet another way in which unelected bureaucrats destroy value and ensure suffering in the field of medicine. One way in which recellularization might alleviate these human-caused issues is by opening the door to safe and widespread use of animal organs for transplant.