Heart cells 'can learn to heal'

Cells in the heart's outer layer can be guided deeper inside by a specific protein in order to help repair a failing adult heart, new research has revealed.

A study by scientists at University College London, published in 'Nature', showed how thymosin beta 4, a protein already known for its ability to reduce muscle cell loss after heart attack, could instruct the heart to heal itself.

The potential repair cells are known as progenitors - they are similar to stem cells in that they are blank cells that can change into different cell types depending on the signals they receive in the body.

A team from UCL, led by Dr Paul Riley, said that they had discovered that thymosin beta 4 could stimulate new blood vessel generation from progenitor cells from the outermost layer of the adult heart.

It had previously been thought that cells within the adult heart are in a state of permanent rest and that any progenitor cells that can contribute to heart tissue repair travel into the heart from the bone marrow.

Dr Riley's team studied mice bred to lack thymosin beta 4 in their hearts.

They found that the hearts of these mice did not develop normally, the heart muscle showed early signs of tissue loss and blood vessel development.

The team said that, without thymosin beta 4, the progenitor cells failed to move deeper into the heart and change into the cells needed to build healthy blood vessels and sustain muscle tissue.

Dr Riley said: "We found that, when treated with thymosin beta 4, these adult cells have as much potential as embryonic cells to create healthy heart tissue."

He said that using thymosin beta 4 would make it possible to better repair damaged adult hearts.

He added: ‘‘Our research has shown that blood vessel regeneration is still possible in the adult heart. In the future if we can figure out how to direct the progenitor cells using thymosin beta 4, there could be potential for therapy based on the patients’ own heart cells. This approach would bypass the risk of immune system rejection, a major problem with the use of stem cell transplants from another source. And, it has the added benefit that the cells are already located in the right place - within the heart itself. All these cells need is the appropriate instructions to guide them towards new blood vessel formation that will help in the repair of muscle damage following a heart attack.’’

The British Heart Foundation and the Medical Research Council funded the research.

Professor Jeremy Pearson, Associate Medical Director at the British Heart Foundation, said: "These results are important and exciting. By identifying for the first time a molecule that can cause cells in the adult heart to form new blood vessels, Dr Riley’s group have taken a large step towards practical therapy to encourage damaged hearts to repair themselves, a goal that researchers are urgently aiming for.”

Professor Colin Blakemore, Chief Executive of the Medical Research Council, said: "Finding out how this protein helps to heal the heart offers enormous potential in fighting heart disease, which kills more than 105,000 people in the UK every year. This is an excellent example of the way in which first-class research, at the most basic molecular level, can produce opportunities for translation into innovative new treatments that should help patients and improve their lives.”

(KMcA/EF)