Coming soon: Artificial hearts!
A team, led by Dr Doris Taylor of the University of Minnesota, which is carrying the experiment, believes that the artificial organs could start beating within weeks, and would pave the way for livers, lungs or kidneys to be made to order.
To create the artificial hearts, the scientists have removed muscle cells from donor organs to leave behind tough hearts of connective tissue. Subsequently, they injected stem cells which multiplied and grew around the structure, turning into healthy heart cells, the `Daily Mail` reported.
"The hearts are growing, and we hope they will show signs of beating within the next weeks. There are many hurdles to overcome to generate a fully functioning heart, but my prediction is that it may one day be possible to grow entire organs for transplant," Dr Taylor was quoted as saying.
Patients given normal heart transplants must take drugs to suppress their immune systems for the rest of their lives. This can increase the risk of high blood pressure, kidney failure and diabetes.
If new hearts could be made using a patient`s own stem cells, it is less likely they would be rejected. The lab-grown organs have been created using these types of cells — the body`s immature "master cells" which have the ability to turn into different types of tissue.
The experiment follows a string of successes by the team trying to create spare body parts for transplants. They have already created beating rat and pig hearts. Although they were too weak to be used in animals, the work was an important step towards tailor-made organs.
In their latest research, reported at the American College of Cardiology`s annual conference in New Orleans, they created new organs using human hearts taken from dead bodies.
The scientists stripped the cells from the dead hearts with a powerful detergent, leaving "ghost heart" scaffolds made from the protein collagen. The "ghost hearts" were then injected with millions of stem cells, which had been extracted from patients and supplied with nutrients.
The stem cells recognised the collagen heart structure and began to turn into heart muscle cells. The hearts have yet to start beating – but if they do, they could be strong enough to pump blood, say the scientists.
However, the race to create a working heart faces many obstacles. One of the biggest is getting enough oxygen to the organ through a complex network of blood vessels.
Dr Taylor told `The Sunday Times`: "We are a long way off creating a heart for transplant, but we think we`ve opened a door to building any organ for human transplant."