Decellularization is the process of taking an existing organ and stripping its cells, leaving the intricate skeleton of the extracellular matrix intact. That can then be repopulated by a patient's own cells to recreate a donor organ for transplant, though only a few organs have been successfully rebuilt in this way so far. As a technique this has many advantages over simple transplants: it removes the possibility of immune rejection, makes the use of animal organs practical, and rehabilitates donor organs that would otherwise be unsuitable:
[Perhaps a fifth of the] kidneys from deceased donors are thrown away each year due to damage. A paper [published] earlier this month suggests that they could be put to use as raw material for engineering new kidneys. The study's authors treated discarded human kidneys with a detergent, which cleared the organ of cells and left only the cells' extracellular matrices. The eventual plan is to grow the patients' own cells on the scaffold, producing a kidney that the patients would be less likely to reject than an ordinary transplant. "These kidneys maintain their innate three-dimensional architecture, their basic biochemistry, as well as their vessel network system."
The scientists tested the scaffold for antigens that might cause a patient to reject the organ and found that they had been eliminated along with the cells. When the researchers transplanted the modified kidneys into pigs and connected their vasculature to the pigs' circulatory systems, blood pumped through the kidneys at normal pressure. "With about 100,000 people in the U.S. awaiting kidney transplants, it is devastating when an organ is donated but cannot be used. These discarded organs may represent an ideal platform for investigations aimed at manufacturing kidneys for transplant."