Adult Stem Cells Build a New Heart

I reported on this story previously from a different angle, e.g. the need for using animals in basic medical research. But this picture is so amazing, that I thought the breakthrough was worth revisiting to discuss the biotechnological implications.

To recap: scientists created a new beating heart using cells from newborn mice and and hearts from dead rats. From the story:

[Doris] 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.

Have no fear, newborns would not be used in people:

To apply this method to people, the heart scaffolding could come from either human cadavers or pigs, Taylor says. Adult stem cells, such as those found in bone marrow, could be taken from patients awaiting transplants and used to grow the new heart.

If this worked in people, it would permit heart patients to receive custom made, immunologically compatible hearts for transplantation without the need for human cloning and fetal farming. Obviously, there is a long way to go still, but this sure seems pretty nifty.