Scientists Make Progress in Growing Organs From Stem Cells

Progress in tissue engineering: "scientists have created human kidneys from stem cells ... The artificial organs were created in a laboratory using human amniotic fluid and animal foetal cells. They are currently half a centimetre in length - the same size as kidneys found in an unborn baby. [Scientists] hope they will grow into full-size organs when transplanted into a human. ... It sounds a bit science fiction-like but it's not. The idea is to start with human stem cells and end up with a functioning organ. We have made pretty good progress with that. We can make something that has the complexity of a normal, foetal kidney ... The research team hope that doctors will eventually be able to collect amniotic fluid, which surrounds the growing embryo in the womb, when a baby is born. This will then be stored by scientists in case that person develops kidney disease later in life. The fluid can then be used to create a matching kidney. Creating an organ using a patient's own stem cells solves the problem of having to use powerful immuno suppressant drugs to stop the body rejecting a another person's kidney. ... the technology could be ready for use on humans in around 10 years." By which time it will probably be unnecessary to collect amniotic fluid, as the signals and chemicals it provides will be understood and reproduced

Growing lungs and other organs for transplant is still in the future, but scientists are working toward that goal. In North Carolina, a 3D printer builds prototype kidneys. In several labs, scientists study how to build on the internal scaffolding of hearts, lungs, livers and kidneys of people and pigs to make custom-made implants.

Cell replacement has also worked for kidneys. recently reported that lab-made kidneys in rats didn't perform as well as regular kidneys. But, he said, just a "good enough organ" could get somebody off dialysis. He has just started testing the approach with transplants in pigs.

it is also working to grow human cells on human and pig heart scaffolds for study in the laboratory.

There are plenty of challenges with this organ-building approach. One is getting the right cells to build the organ. 

Others look to stem cells from bone marrow or body fat that could be nudged into becoming the right kinds of cells for particular organs. In the near term, organs might instead be built with donor cells stored in a lab, and the organ recipient would still need anti-rejection drugs.