Growing the Heart – Stem Cells Hold the Key

Scientists in Britain have achieved a major breakthrough in tissue engineering – they have managed to grow part of a human heart from stem cells. This is the first time part of a human heart has been engineered in the laboratory.

The feat was achieved by heart surgeon Sir Magdi Yacoub and his team at the Harefield Hospital. The team consisted of physicists, pharmacologists, clinicians and cellular scientists. It took the research team 10 years in achieving this major step towards growing entire organs for transplant.

Stem cells are believed to be the building blocks to a variety of cells in the human body. In the opinion of many scientists working in this area, the ability of stem cells to grow into different tissues should make it possible to use them to repair organ damage and treat diseases.

Researchers have already achieved success in growing lesser complex organs like tendons, cartilages and bladders from stem cells. However all efforts at growing heart tissue had so far been unsuccessful. Sir Magdi, Professor of Cardiac Surgery at Imperial College London had been working on a way to grow heart tissue so as to reduce the shortage of donated hearts for patients.

For growing the cells, Sir Magdi’s team extracted stem cells from bone marrow and cultivated them into heart valve cells. They placed the extracted stem cells in special scaffolds formed from collagen. These cells then grew into 3 cm-wide discs of heart valve tissue. The tissue that has been grown works in the same way as human heart valves. The research team now plans on implanting these tissues into animals like sheep or pigs to assess how well they fare.

Based on their success, Sir Magdi believes doctors could be using artificially grown heart components in transplants within three years. He also believes that 10 years down-the-line it would be possible to produce a whole heart from stem cells. “It is an ambitious project but not impossible. If you want me to guess I’d say 10 years,” he stated.

Heart valves are much more complex than the artificial alternatives currently being used in surgery. They don’t simply open or close; they actually anticipate the changes in the method of blood flow and respond accordingly. Sir Magdi’s team hopes the valves they are growing will be equally sophisticated.

Theoretically speaking, a heart valve grown from a patient’s own cells would remove the necessity to administer drugs to stop the body from rejecting it. Such natural valves would also have the potential to last much longer than artificial valves, which need to be replaced after a few years.

Dr. Adrian Chester, a senior member of the research team said, “We are attempting to grow a valve that will be functional in adults and children and will be made entirely of living tissue. Hopefully it will be able to adapt to its environment, and then just sit there and function just as a normal valve functions under normal physiological conditions.” According to Dr. Chester their work could ultimately mean certain patients might never need a heart transplant.

Dr. Stephen Minger, a stem cell expert at London’s King’s College believes Sir Magdi’s team is at the forefront of tissue engineering for cardiac disease. “If the valves they’ve engineered prove successful in experimental animals, this could open the door to generating complex tissues from stem cells for a wide variety of clinical applications. But as they stress, this is very preliminary work and the direct translation to human is still some way off in the future.”

Professor John Martin of the British Heart Foundation, which supported the research said, “This opens the possibility that whole parts of the heart may be made in the laboratory from the patient’s own stem cells.” He said patients could benefit because using the tissue could prevent the need for a heart transplant.

Professor Martin added, “Although the work carried out at the Harefield Hospital is exciting, there is a long road to be travelled before patients awaiting heart transplants will benefit from this research.”

source:www.heartzine.com