British scientists grow part of a human heart from stem cells

Here's one of those "isn't-science-brilliant" stories, pure and simple. We've heard about the potential for stem cell research for soooo long now and work has been going reasonably steadily - everything from extracting stem cells from various sources, working out how to turn them into useful tissues to navigating a tricky ethical minefield.

A story I wrote for the Guardian this week describes work by Professor Sir Magdi Yacoub of Harefield Hospital and Imperial College. His research team has been working for more than a decade to grow heart tissue for transplants.

The follow-up to the story, by other newspapers and broadcast outlets, interviewed patients and scientists to guage how excited they were about the work - I heard someone on the Today programme this morning talking about how her daughter had just had heart surgery and that work like Prof Yacoub's gives her hope for her child's future. remarkable stuff, I though but I leave you to judge for yourself...

A British research team led by the world's leading heart surgeon has grown part of a human heart from stem cells for the first time. If animal trials scheduled for later this year prove successful, replacement tissue could be used in transplants for the hundreds of thousands of people suffering from heart disease within three years.

Sir Magdi Yacoub, a professor of cardiac surgery at Imperial College London, has worked on ways to tackle the shortage of donated hearts for transplant for more than a decade. 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; by 2010, it is estimated that 600,000 people around the world will need replacement heart valves. "You can see the common pathway of death and suffering is heart failure," said Prof Yacoub. "Reversing heart failure could have a major impact."

Growing replacement tissue from stem cells is one of the principal goals of biology. If a damaged part of the body can be replaced by tissue that is genetically matched to the patient, there is no chance of rejection. So far, scientists have grown tendons, cartilages and bladders, but none of these has the complexity of organs, which are three-dimensional structures of dozens of different types of cells.

To crack the problem, Prof Yacoub assembled a team of physicists, biologists, engineers, pharmacologists, cellular scientists and clinicians. Their task - to characterise how every bit of the heart works - has so far taken 10 years. The progress of his team and that of colleagues around the world will be published in August in a special edition of the journal Philosophical Transactions of the Royal Society.

Prof Yacoub said his team's latest work had brought the goal of growing a whole, beating human heart closer. "It is an ambitious project but not impossible. If you want me to guess I'd say 10 years. 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, many 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," said Prof Yacoub.

Adrian Chester, one of the lead scientists at the Harefield centre, has focused on characterising the valves in the heart. "You have mediators in blood or released locally in the valve that can make parts of the valve contract and relax. That work has then extended into looking at the incidence of nerves in the valve - these can cause the types of contractions and relaxations in a very specific way."

By using chemical and physical nudges, the scientists first coaxed stem cells extracted from bone marrow to grow into heart valve cells. By placing these cells into scaffolds made of collagen, Dr Chester and his colleague Patricia Taylor then grew small 3cm-wide discs of heart valve tissue. Later this year, that 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, Prof 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.

Growing a suitably-sized piece of tissue from a patient's own stem cells would take around a month but he said that most people would not need such individualised treatment. A store of ready-grown tissue made from a wide variety of stem cells could provide good matches for the majority of the population.

Prof Yacoub's inspiration has come not only from other scientists but also from an unexpected source - the celebrated British artist, Antony Gormley, who has donated a sculpture to the heart science centre. "We need a lot of experts from different fields but we also need a lot of imagination and a lot of understanding of how form interacts with function," said Prof Yacoub. "Art gives a lot of inspiration and beauty. And beauty is part of science."

Mr Gormley, who has also contributed to the upcoming special issue of the Philosophical Transactions of the Royal Society with an article on the relationship between form and function in sculpture, said he admired the universalism with which Prof Yacoub approached his work. "He manages to do the Robin Hood job in a very important way for the benefit of all humanity. I found in him a fellow traveller in terms of trying to do things at the fringes of the possible with the highest levels of input in terms of technology and intelligence. Everybody breathes air, everybody pumps blood."

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Luddites and moralists

From time to time, the stem cells wars flare up. The US famously doesn't allow public money to be spent on this research (mostly because of George Bush's ideological objections) but I thought the UK was a always a bit more sensible. Well, not any more. The government wants to ban the creation of hybrid animal-human embryos as a source of stem cells in its new white paper on fertility legislation. Why? Because the public says so, apparently.

It's pig-headed ignorance from the government and, if their attempts to ban the work are successful, what a horrible mistake it will be. (An interesting addendum to all this - a new source of stem cells from amniotic fluid.)

A ban on the use of hybrid embryos will be the consequence of ill conceived pressure

Thursday January 11, 2007
The Guardian

The honeymoon for British stem cell scientists is coming to an end. What began as a model partnership between researchers and the government in how to navigate a controversial area is at risk of disintegrating into a messy divorce, a split fuelled by misconceptions, a Luddite fear of technology and more than a whiff of inappropriate political pressure.

Two research teams in London find out today whether they will be allowed to create animal-human hybrid embryos as part of their work. Informally, they have already been told by the Human Fertilisation and Embryology Authority (HFEA) that their application is unlikely to succeed, despite it being allowed under current regulations. Last week several scientists got together to express deep concerns about the impending decision and delivered a stark message: banning the creation of hybrids will stifle development of treatments for diseases such as diabetes and Parkinson's.

In the US, where public funding of stem cell research has been curtailed by George Bush's ideological objections, such a move might not have caused much of a storm. But in the UK it is unprecedented. The HFEA's ethical stance on fertility and stem cell research is well respected and its decisions have always taken into account the latest scientific thinking.

The scientists' argument is one of necessity - to make any headway in stem cell work, researchers need raw materials. This means as many stem cells as they can lay their hands on and, typically, these come from the fertilised embryos left over from IVF treatments that are donated for research. But this resource is very small and animal eggs are much easier to come by.

In making the hybrid, the animal egg is hollowed of all genetic information and replaced with the nucleus of a human cell. The resulting cell is then induced to divide and eventually becomes an early-stage embryo. Genetically, the hybrid is 99.5% human and the embryo is terminated before it reaches 14 days' old, at which time it is a ball of cells no bigger than a pinhead. The stem cells exist inside this early-stage embryo, ready to be extracted for research.

But when public health minister Caroline Flint unveiled the white paper on fertility research last month, the clause on animal-human hybrid embryos flew in the face of all of the scientific advice, proposing that it should not be allowed. Flint cited a preceding consultation as justification for the government's reversal of support. But the extent to which these sorts of consultations can be hijacked by pressure groups is well known.

There are also inadvertent victims in this sudden government hostility. Last year, scientists created a model of Down's syndrome by fusing human cells with embryonic stem cells from mice. The resulting animals were hailed as a crucial tool in the study of a condition that affects 60,000 people in the UK alone. Were the government to get its way, the Down's mouse would fall foul of the new legislation.

If the HFEA confirms today that it will not allow scientists to create hybrids, the spotlight will shift to the authority. Why does an independent scientific agency feel the need to prevent hybrid research? Indeed, why is it going against its own advice on the issue?

The only conceivable explanation is that the HFEA is feeling undue political pressure from its host department. The Department of Health seems to have made its decision based on a misconception about public unease over hybrid research. It is difficult not to conclude that the HFEA is worried that funds will be cut off if it doesn't fall into line.

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