A recent study by researchers at the Cedars-Sinai Heart Institute has revealed that adult stem cells can actually repair the damage caused by a heart attack.
In an article for BBC News, health and science reporter James Gallagher explained that a heart attack occurs when the organ is starved of oxygen, as when a clot blocks the flow of blood to the heart. An attack leaves dead muscle within the heart, which is replaced with scar tissue as the organ heals. Because this scar tissue does not beat like heart muscle does, the heart's ability to pump blood around the body is reduced after a heart attack. 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."
The trial 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 sample of heart tissue was taken from each patient and 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."
In each pre-treatment patient, scar tissue accounted for an average of 24% of the left ventricle, a major chamber of the heart. This percentage went down to 16% after six months and 12% after a year, and 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."
Although experts agree that the results need further clarification and evidence, the discovery still marks an important milestone in stem cell research, which bodes well for the variety of companies involved in the industry.
Dr Eduardo Marban, one of the trial researchers, commented,
"While the primary goal of our study was to verify safety, we also looked for evidence that the treatment might dissolve scar and regrow lost heart muscle. This has never been accomplished before, despite a decade of cell therapy trials for patients with heart attacks. Now we have done it. The effects are substantial, and surprisingly larger in humans than they were in animal tests."
Professor Jeremy Pearson, associate medical director at the British Heart Foundation, added,
"It's the first time these scientists' potentially exciting work has been carried out in humans, and the results are very encouraging. These cells have been proven to form heart muscle in a petri dish but now they seem to be doing the same thing when injected back into the heart as part of an apparently safe procedure. It's early days, and this research will certainly need following up, but it could be great news for heart attack patients who face the debilitating symptoms of heart failure."