Damage caused by a heart attack has been healed using stem cells gathered from the patient’s own heart, according to doctors in the US. The authors said there was also an “unprecedented” increase in new heart muscle.
The British Heart Foundation said it was “early days”, but could “be great news for heart attack patients”.
As the heart heals, the dead muscle is replaced with scar tissue, but because this does not beat like heart muscle the ability to pump blood around the body is reduced.
Doctors around the world are looking at ways of “regenerating” the heart to replace the scar tissue with beating muscle. Stem cells, which can transform into any other type of specialised cell, figure prominently in their plans.
This trial, at the Cedars-Sinai Heart Institute, was designed to test the safety of using stem cells taken from a heart attack patient’s own heart.
Within a month of a heart attack, a tube was inserted into a vein in the patient’s neck and was pushed down towards the heart. A sample of heart tissue, about “half the size of a raisin”, was taken.
This was taken to the laboratory where the stem cells were isolated and grown. Up to 25 million of these stem cells were then put into the arteries surrounding the heart.
Twenty five patients took part in the trial. Before the treatment, scar tissue accounted for an average of 24% of their left ventricle, a major chamber of the heart. It went down to 16% after six months and 12% after a year.
Healthy heart muscle appeared to take its place. The study said the cells, “have an unprecedented ability to reduce scar and simultaneously stimulate the regrowth of healthy [heart] tissue”.
Prof Anthony Mathur, who is co-ordinating a stem cell trial involving 3,000 heart attack patients, said that even if the study found an increase in ejection fraction then it would be the source of much debate.
He argued that as it was a proof-of-concept study, with a small group of patients, “proving it is safe and feasible is all you can ask”.
“The findings would be very interesting, but obviously they need further clarification and evidence,” he added.