Doctors produce heart valve from living cells
Swiss researchers have produced the first artificial heart valve made of living tissue, offering new hope to children born with defective hearts.
Unlike synthetic heart valves, the new valve will grow with the child, avoiding years of risky operations.
A team at the Tissue Engineering Laboratory of Zurich University Hospital’s Clinic for Heart and Blood Vessel Surgery succeeded in implanting the heart valve in a sheep. Trials on humans are not expected for a couple of years.
The implications of a heart valve made of living tissue are far-reaching for cardiac patients, especially children.
Dr Simon Hoerstrup, one of team’s research directors, said the new valve would be made from the patient’s own cells.
Self repair
“Nowadays, if someone needs a heart valve replacement, they get a prosthesis made of dead or artificial matter,” he told swissinfo.
“The idea of tissue engineering is that we can construct a heart valve from the patient’s own cells so that you have a living heart valve.”
At present patients receive artificial heart valves made of plastic or metal.
Dr Hoerstrup explained that although these valves have the advantage of being durable, there can be severe side affects due to the special medication that is often needed to thin the blood.
“The big advantage of a living heart valve is that it is living tissue, so it can repair itself, ” he explained.
“These living cells have the potential to repair the heart valve on an ongoing basis, which is important because in a lifetime of about 70 years, a heart normally beats about two to three billion times and this is an enormous challenge for this tissue.”
New hope for children
The discovery is being seen as a major breakthrough for the future treatment of children born with defective hearts.
According to Hoestrup, damaged or diseased heart valves affect up to one per cent of all newborns.
Children normally receive mechanical valve replacements. But because children’s organs grow so rapidly, these devices frequently need to be replaced, leading to potentially risky multiple operations throughout childhood.
“The big advantage for a baby is that you can construct the heart valve at once and then in the best cases, no re-operation is needed,” said Hoerstrup.
Human trials
He said tests on animals had produced very promising results after only a few months, adding that it should be possible to develop a living heart valve for humans by tissue engineering.
Hoerstrup revealed that the team would be undertaking experiments on animals to determine the long-term effects of living heart valves before starting clinical trials on people.
“A clinical application is certainly a couple of years ahead but we are coming closer year by year,” he said.
swissinfo, Isobel Johnson
A heart has four valves, which act like one-way doors to keep blood moving in one direction through the heart.
A defective heart valve is one that fails either to close or to open fully.
Heart valve disease usually affects people over 60.
The condition can be present at birth (congenital heart disease), the child being born with valves made of two parts rather than the usual three.
Diseased valves are usually replaced by manufactured valves or animal valves.
There is a 5% chance of a patient dying after valve replacement surgery.
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