Small-scale study that injected stem cells into patients’ hearts during surgery offers hope to those with cardiac disease

Embryonic stem cells seen through a microscope
Embryonic stem cells seen through a microscope. The study saw a 40% reduction in the size of scarred tissue on the patients’ hearts.
Photograph: Mauricio Lima/AFP/Getty Images

People suffering from heart disease have been offered hope by a new study that suggests damaged tissue could be regenerated through a stem cell treatment injected into the heart during surgery.

The small-scale study, published in the Journal of Cardiovascular Translational Research, followed 11 patients who during bypass surgery had stem cells injected into their hearts near the site of tissue scars caused by heart attacks.

One of the trial’s most dramatic results was a 40% reduction in the size of scarred tissue. Such scarring occurs during a cardiac event such as a heart attack, and can increase the chances of further heart failure. The scarring was previously thought to be permanent and irreversible.

At the time of treatment, the patients were suffering heart failure and had a very high (70%) annual mortality rate. But 36 months after receiving the stem cell treatment all are still alive, and none have suffered a further cardiac event such as a heart attack or stroke, or had any readmissions for cardiac-related reasons.

According to the British Heart Foundation, while there are several treatments to help people with heart failure, there is no known cure, and in some cases a heart transplant may be the only option.

Twenty-four months after participants were injected with the stem cell treatment there was a 30% improvement in heart function, 40% reduction in scar size, and 70% improvement in quality of life, as judged by the Minnesota living with heart failure (MLHF) score.

“Quite frankly it was a big surprise to find the area of scar in the damaged heart got smaller,” said Prof Stephen Westaby from John Radcliffe hospital in Oxford, who undertook the research at AHEPA university hospital in Thessaloniki, Greece, with Kryiakos Anastasiadis and Polychronis Antonitsis.

Westaby began theorising about the impact of stem cells on regenerating heart tissue and reducing scarring after observing how scar tissue on the hearts of babies who have had heart attacks and undergone heart failure disappeared by the time they reached adolescence, suggesting that residual stem cells might be able to repair the damaged tissue.

“It’s an early study and it’s difficult to make large-scale predictions based on small studies,” said Ajan Reginald, the founder of Celixir, the company that produces the treatment. “But even in a small study you don’t expect to see results this dramatic.

“These are 11 patients who were in advanced heart failure, they had had a heart attack in the past, multiple heart attacks in many cases. The life expectancy for these patients is less than two years, we’re excited and honoured that these patients are still alive.”

Jeremy Pearson, the associate medical director at the British Heart Foundation (BHF), said: “This very small study suggests that targeted injection into the heart of carefully prepared cells from a healthy donor during bypass surgery, is safe. It is difficult to be sure that the cells had a beneficial effect because all patients were undergoing bypass surgery at the same time, which would usually improve heart function.

“A controlled trial with substantially more patients is needed to determine whether injection of these types of cells proves any more effective than previous attempts to improve heart function in this way, which have so far largely failed.”

Westaby conceded that the improvement in patients’ health was partly due to the heart bypass surgery those in the study were undergoing, and said the next study would include a control group who undergo bypass but do not receive stem cell treatment, to measure exactly what impact the treatment has.

“These patients came out of heart failure partly due to the bypass grafts of course, but we think it was partly due to the fact that they had a smaller area of scar [as a result of the stem cell treatment]. Certainly this finding of scar being reduced is quite fascinating,” he said.

Westaby will commence a large-scale controlled study later this year at the Royal Brompton hospital in London, and Celixir hopes to make the Heartcel treatment available to patients in 2018 or 2019.