Scientists grow heart tissue from embryonic stem cells

Scientists have grown human heart tissue in a test-tube using embryonic stem cells that have demonstrated yet again their potential to revolutionise transplant medicine.

Scientists have grown human heart tissue in a test-tube using embryonic stem cells that have demonstrated yet again their potential to revolutionise transplant medicine.

The "beating" muscle cells display many characteristics of fully functioning cardiac tissue and could one day be used to repair damaged hearts rather than relying on donor organs. A week ago, another team of scientists created kidney tissue from adult stem cells extracted from bone marrow.

But by yesterday, the US House of Representatives had voted to stop the cloning of human embryonic stem cells that could be used to treat incurable diseases with transplanted tissue.

The heart cells were grown by a team led by Lior Gepstein, of the Technion-Israel Institute of Technology in Haifa, using stem cells taken from embryos just a few days old. Tests showed the cells were cardiomyctes, the early muscle cells of the heart, which beat spontaneously and eventually develop into fully mature heart cells. "We compared the genes that are turned on or activated in these cells with the genes in known cardiomyctes," Dr Gepstein said.

"We looked at the proteins in the cells, and the cells' electrical activity as they regularly contracted. We also looked at the cells' structure under an electron microscope and at their chemical activity. Finally, we looked at how these cells respond to hormones like adrenalin, which causes heart muscles to contract faster."

The research has now been published in the Journal of Clinical Investigation.

Sir Charles George, the medical director of the British Heart Foundation, said: "A fascinating and important milestone has been reached. It gives real hope that people with heart disease may benefit from stem cell technology."

Professor Patrick Bateson, vice-president of the Royal Society, which strongly supports embryonic stem cell research, said: "If this is right, it's a very important advance, and will provide real uses for stem cells which people have been predicting for a long time."

The next step is to see whether these cells can rejuvenate and repair a damaged heart when they are injected into a patient with heart disease, Dr Gepstein said.

At the end of last month, 129 patients in Britain were waiting for new hearts and 82 for heart and lung transplants. There were 77 heart, and 20 heart and lung transplants during the year to the end of June.