Stem cells could grow into new hearts

It is the ultimate cure for diseased hearts. When the muscle softly beating behind the ribcage starts to fail – grow a new one.

Professor Magdi Yacoub, Britain's best-known cardiac surgeon, who pioneered heart transplants in the 1980s, champions a new approach to heart surgery involving patients growing their own heart tissue to replace damaged parts of the existing organ.

Using stem cells taken from bone marrow, Professor Yacoub says heart valves and muscles can be grown in the laboratory ready for transplant within six weeks. The technique, which could ultimately be used to grow a complete new ventricle (pumping chamber), could be ready for human trials within three to five years.

Professor Yacoub retired from operating in 2001, but has continued his research at the Heart Science Centre at Harefield hospital, Middlesex. In today's special issue of the Royal Society journal, Philosophical Transactions B, titled Bioengineering the heart, Professor Yacoub charts the progress of research in his own centre and worldwide towards achieving the goal of growing a new heart.

The first stage is to grow new heart valves, which it is estimated will be needed for 80,000 people worldwide by 2020. Valve replacements are currently obtained either from pigs or made artificially from metal, but they do not work as well as human valves and wear out after 10 to 15 years.

Heart muscles could also be grown from stem cells in the laboratory. They would be especially valuable in young people, who would otherwise face a series of operations throughout their lifetime as their replacement valves wear out. A valve obtained from stem cells would grow and repair like the patient's own heart tissue.