Skin cells from patients with advanced heart failure were turned into beating heart cells in a dish that were young and healthy. Video: Lior Gepstein European Heart Journal

Scientists have turned skin tissue from heart attack patients into fresh, beating heart cells in a first step towards a new therapy for the condition.

The procedure may eventually help scores of people who survive heart attacks but are severely debilitated by damage to the organ.

By creating new heart cells from a patient's own tissues, doctors avoid the risk of the cells being rejected by the immune system once they are transplanted.

Though the cells were not considered safe enough to put back into patients, they appeared healthy in the laboratory and beat in time with other cells when implanted into rats.

"We have shown that it's possible to take skin cells from an elderly patient with advanced heart failure and end up with his own beating cells in a laboratory dish that are healthy and young – the equivalent to the stage his heart cells were in when he was just born," said Lior Gepstein, a cardiologist at Technion-Israel Institute of Technology in Haifa.

The technique was first demonstrated with human cells in 2007, when two teams of scientists, Shinya Yamanaka in Japan, and James Thomson in the US, identified "pluripotency" genes that could wind back the clock for adult cells to a younger stage of development.

In the new study, researchers led by Gepstein took skin cells from two men, aged 51 and 61, who had survived heart attacks, and reprogrammed them into an immature state by infecting them with a virus that carried three pluripotency genes.

The scientists then grew these "induced pluripotent stem cells" into fresh heart muscle, and removed the virus and extra genes used in the procedure.

The cells looked healthy in a Petri dish and crucially, when injected into rat hearts, were woven into the organ and worked alongside the muscle cells already there.

"What was interesting was the cells could integrate with the rat tissue and contract in synchrony. If you put the cells in and they beat with a completely different timing, you wouldn't see any improvement in heart function and may even cause a dangerous arrhythmia," Gepstein told the Guardian. The work appears in the European Heart Journal.

The technique must overcome major hurdles before doctors can begin clinical trials, but the latest work has boosted confidence that it has potential to help patients. Further experiments to investigate whether the procedure is safe and effective are expected to take up to 10 years, the team said.

One concern is that reprogrammed cells might grow into tumours when implanted in patients, unless they are carefully screened beforehand. A further complication is that heart attacks cause the growth of scar tissue that might have to be removed for replacement cells to improve heart function.

Making enough cells quickly enough will be another hurdle. In the latest study, researchers injected a few million cells into rats, but a heart attack kills off around a quarter of the four billion muscle cells in the human heart. It took two weeks to make heart cells from skin tissue, so patients could not be treated soon after suffering an attack, Gepstein said.

"More people are surviving following a heart attack than ever before and therefore the number of people living with a damaged heart and heart failure is increasing," said Nicholas Mills, a consultant cardiologist at Edinburgh University. "Unfortunately, the body has only very limited capacity to repair the heart following a heart attack. There is therefore an urgent need to develop effective and safe treatments to regenerate the heart."

"This technology needs to be refined before it can be used for the treatment of patients with heart failure, but these findings are encouraging and take us a step closer to our goal of identifying an effective means of repairing the heart and limiting the consequences of heart failure," he added.

Tim Nelson, who works on regenerative medicine at the Mayo Clinic in Minnesota, said the work improved scientists' understanding of how induced pluripotent stem cells might be used to treat humans with heart disease. "These bioengineered cells have been demonstrated to integrate into the host heart tissue and not disrupt normal electrical activity. This is an important feature required to translate this technology towards clinical applications," he said.