By Fiona MacRae
A tiny beating "heart in a dish" has been grown by Israeli scientists in a world first which will offer hope to millions of cardiac patients.
Such laboratory-reared tissue could one day be used to repair heart attack damage, prolonging and improving the quality of life of tens of thousands of individuals each year.
It could also cut the need for transplants, and, if used to test drugs, reduce the risk of dangerous side-effects when new medicines are finally introduced to patients.
Researcher Lior Gepstein, a cardiologist, said, "This could have a huge impact. Heart failure is a huge problem. It is responsible for more hospitalisation than all forms of cancer combined."
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The Israeli research team used human embryonic stem cells - blank cells with the ability to turn into specialised tissue types.
Crucially, they found a way of persuading the different types of cell which form the heart to grow and work together.
The result was a tiny piece of heart muscle - less than one centimetre square, but threaded with minute blood vessels to resemble the complex tissue of the human heart.
It has a beat, continually contracting and relaxing in the same way as heart muscle.
The generation of blood vessels improves the possibility of success of any tissue grafts, because the heart needs a large and ready supply of oxygen.
The researchers hope to refine the technique to create sections big enough to take the place of muscle scarred by heart attack. The ultimate hope is to reduce the need for transplants.
Fellow researcher Dr Shulamit Levenberg, a biomedical engineer, said, "If we could sew a large enough piece of tissue on to a human heart to maintain a good circulation, there would probably be no need for many transplants."
The first human trials using sections of grown tissue could start within 10 years. Other applications could become reality even sooner.
Gepstein said, "We test drugs on animals, but we would get more reliable results if we tested them on actual human tissues."
Use of such lab-grown tissue could avert disasters such as the "Elephant Man" case in England last March in which drug trial volunteers experienced horrendous side effects.
The researchers, from the Technion-Israel Institute of Technology in Haifa, found a way to coax stem cells into turning into three types of cell.
These cells - heart muscle cells along with endothelial cells and fibroblasts, both of which are key in blood vessel formation - were seeded on to a biodegradable framework. Within a matter of weeks, they had grown and fused.
Gepstein said, "It is like a miniature heart in a dish."
Their creation is now being grafted on to rats' hearts to find out how well it fuses with natural tissue. So far, the scientists have only managed to make a few million cells - a fraction of the billion or so needed to repair the damage done by a severe heart attack.
Even if they do succeed in growing tissue of a practical size, it may be rejected when transplanted into the body.
A way round this would be to create banks of stem cells, which could provide a match for most of those in need of new tissue.
Reliance on embryonic stem cells is likely to disgust those who oppose the use of cells derived from unborn babies in medical research.
However, the work was welcomed by British experts. Prof Jeremy Pearson, of the British Heart Foundation said, "We might even be able to grow heart valves, blood vessels, or even whole hearts.
"To use stem cells to repair damaged hearts we need to get them working together - forming tissue in which cells are organised and able to beat in rhythm. These researchers have for the first time achieved this." - Daily Mail
- This article was originally published on page 13 of Tribune on March 19, 2007
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