British scientists grow human heart valve from stem cells
by FIONA MACRAE
2nd April 2007
Sir Magdi Yacoub has performed more heart transplants than anyone else in the world
A British research team has grown a human heart valve from stem cells in a world first.
If animal tests later this year prove successful, replacement tissue could be used in transplants within three years for hundreds of thousands of people suffering from heart disease.
The world's leading heart surgeon Sir Magdi Yacoub, a professor of cardiac surgery at Imperial College London, led the breakthrough, which has taken a decade to achieve.
His team at the heart science centre at Harefield hospital have grown tissue that works in the same way as the valves in human hearts, a significant step towards the goal of growing whole replacement hearts from stem cells.
According to the World Health Organisation, 15 million people died of cardiovascular disease in 2005 and by 2010, it is estimated that 600,000 people around the world will need replacement heart valves.
Prof Yacoub said: "You can see the common pathway of death and suffering is heart failure. Reversing failure could have a major impact."
If animal tests later this year prove successful, replacement tissue could be used in transplants within three years
The scientists first coaxed stem cells extracted from bone marrow to grow into heart valve cells by using chemical and physical nudges.
Then, by placing these cells into scaffolds made of collagen, they grew small 3cm wide discs of heart valve tissue.
Later this year the tissue will be implanted into animals - probably sheep or pigs - and monitored to see how well it works as part of a circulatory system.
If that trial works well, Dr Yacoub is optimistic that the replacement heart tissue, which can be grown into the shape of a human heart valve using specially designed collagen scaffolds, could be used in patients within three to five years.
So far, scientists have grown tendons, cartilages and bladders, but none of these has the complexity of organs.
To solve the problem, Prof Yacoub assembled a team of physicists, biologists, engineers, pharmolocogists, cellular scientists and clinicians.
It has so far taken them 10 years to characterise how every bit of the heart works.
Prof Yacoub said his team's latest work had brought the goal of growing a whole, beating heart closer.
"It is an ambitious project but not impossible. If you want me to guess I'd say ten years," he said.
"But experience has shown that the progress that is happening nowadays makes it possible to achieve milestones in a shorter time. I wouldn't be surprised if it was some day sooner than we think."
Currently people suffering from heart valve disease have artificial replacement valves.
Though they save lives, the artificial valves are far from perfect. They perform none of the more sophisticated functions of living tissue, children need their valves replaced as they grow, and patients need a lifetime of drugs to prevent complications after surgery.
"The way a living valve functions, it anticipates haemodynamic events and responds and changes its shape and size. It's completely different from an artificial valve which will just open and shut. The heart muscle itself will appreciate something which will make it free to contract properly," Prof Yacoub told the Guardian.
Last month scientists in Israel grew a tiny piece of heart muscle - less than one centimetre square - which was threaded with minute blood vessels to closely resemble the complex tissue of the human heart.
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 in the UK alone each
www.dailymail.co.uk . . .
by FIONA MACRAE
2nd April 2007
Sir Magdi Yacoub has performed more heart transplants than anyone else in the world
A British research team has grown a human heart valve from stem cells in a world first.
If animal tests later this year prove successful, replacement tissue could be used in transplants within three years for hundreds of thousands of people suffering from heart disease.
The world's leading heart surgeon Sir Magdi Yacoub, a professor of cardiac surgery at Imperial College London, led the breakthrough, which has taken a decade to achieve.
His team at the heart science centre at Harefield hospital have grown tissue that works in the same way as the valves in human hearts, a significant step towards the goal of growing whole replacement hearts from stem cells.
According to the World Health Organisation, 15 million people died of cardiovascular disease in 2005 and by 2010, it is estimated that 600,000 people around the world will need replacement heart valves.
Prof Yacoub said: "You can see the common pathway of death and suffering is heart failure. Reversing failure could have a major impact."
If animal tests later this year prove successful, replacement tissue could be used in transplants within three years
The scientists first coaxed stem cells extracted from bone marrow to grow into heart valve cells by using chemical and physical nudges.
Then, by placing these cells into scaffolds made of collagen, they grew small 3cm wide discs of heart valve tissue.
Later this year the tissue will be implanted into animals - probably sheep or pigs - and monitored to see how well it works as part of a circulatory system.
If that trial works well, Dr Yacoub is optimistic that the replacement heart tissue, which can be grown into the shape of a human heart valve using specially designed collagen scaffolds, could be used in patients within three to five years.
So far, scientists have grown tendons, cartilages and bladders, but none of these has the complexity of organs.
To solve the problem, Prof Yacoub assembled a team of physicists, biologists, engineers, pharmolocogists, cellular scientists and clinicians.
It has so far taken them 10 years to characterise how every bit of the heart works.
Prof Yacoub said his team's latest work had brought the goal of growing a whole, beating heart closer.
"It is an ambitious project but not impossible. If you want me to guess I'd say ten years," he said.
"But experience has shown that the progress that is happening nowadays makes it possible to achieve milestones in a shorter time. I wouldn't be surprised if it was some day sooner than we think."
Currently people suffering from heart valve disease have artificial replacement valves.
Though they save lives, the artificial valves are far from perfect. They perform none of the more sophisticated functions of living tissue, children need their valves replaced as they grow, and patients need a lifetime of drugs to prevent complications after surgery.
"The way a living valve functions, it anticipates haemodynamic events and responds and changes its shape and size. It's completely different from an artificial valve which will just open and shut. The heart muscle itself will appreciate something which will make it free to contract properly," Prof Yacoub told the Guardian.
Last month scientists in Israel grew a tiny piece of heart muscle - less than one centimetre square - which was threaded with minute blood vessels to closely resemble the complex tissue of the human heart.
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 in the UK alone each
www.dailymail.co.uk . . .
