Donated hearts for lifesaving transplants are scarce, but now researchers may have hit upon a way to generate the blood-pumping organs in the lab–at least in rats. The approach, which involves transplanting cells from a newborn rat onto the framework of an adult heart, produced an organ that could beat and pump fluid. Further refinement will be necessary before the technique is ready for people, but it could also generate other organs.
Taylor’s team started with a heart removed from an adult rat. The researchers soaked it in chemicals to remove the living cells, leaving behind a “skeleton” composed of the heart’s nonliving structural tissues, which are made of proteins and other molecules. Onto this scaffolding the researchers placed heart cells from a newborn rat, which are not stem cells but can give rise to multiple types of tissue. The cells took to their new home and after 8 days had assembled into a functioning heart that beat and pumped fluid, the researchers reported online 13 January in Nature Medicine. The new organ had only 2% of the pumping force of an adult heart, but Taylor says that she and her colleagues have since repeated the procedure with about 40 hearts and found that they can produce a stronger organ by adding more cells and giving them more time to grow.