That is the long term objective of much stem cell research. Entire organs need to grow “in situ” with all the other organs so as to form properly, but “bits” such as heart valves and ligaments should be possible.
Isn’t that cool? Scientists have actually managed to grow a functional rat kidney from stem cells, and transplanted it into a live rat! Granted, it didn’t exactly come from a single stem cell in a petri dish – this kidney was grown onto the protein skeleton of another kidney. What this means is that, even if the cells in your kidney are diseased and dying, you can take that bad kidney out, take away all the cells so that just the protein frame is left, and then regrow the organ using new cells. Using the protein frame is a handy way of telling cells where to go – in the future we could probably figure out a way to build an organ from scratch, but for now this is a great way to make whole organs, rather than just the ‘parts’ that Peter mentioned.
The coolest thing about growing organs from stem cells is that you wouldn’t grow them from just anyone’s stem cells – you’d grow them from YOUR stem cells, so that the organ would be 100% yours. The way we do it now, transplanting organs from other people, means that your immune system often starts attacking it, because it thinks the organ is invading your body! That means people who get transplants have to take immunosuppressant drugs for the rest of their lives (which leaves them vulnerable to all sorts of other diseases), and even then the precious transplanted organ will only last for 5 to 10 years before it gets too damaged to work anymore. An organ grown from your own stem cells would get rid of all these problems, because your immune system would be perfectly happy to protect one of your own!
Scientists are really not far away from doing this, at least with parts of organs- its the main point of doing stem cell research.
A stem cell is one which has not decided what it is going to grow into- it is ‘unspecialized’. This means that under the right conditions we can tell them what to grow into and give them a hand to do that.
if we could grow organs it would save patients the agony of having to wait for a donor, as the organ could be grown from their own stem cells.