Stem cell research could cure heart attack damage

A PILL that enables damaged hearts to repair themselves could be a reality within 10 years, thanks to a British stem cell breakthrough.

Scientists have discovered that a natural embryo molecule can awaken dormant repair cells in adult hearts.

In future, it could form the basis of a drug that helps damaged heart muscle be rebuilt after a heart attack.

Tests on mice showed it was possible to improve the pumping efficiency of damaged hearts by 25%.

Even half that level of benefit could transform the lives of millions of people suffering the after-effects of a heart attack.

Professor Peter Weissberg, medical director of the British Heart Foundation, which funded the research led by University College London scientists, said: “Even five years ago, people would have said this is science fiction, science fantasy.”

Until recently, experts agreed the heart was inherently irreparable. Once damaged, it stayed damaged.

Then research on the changes that occur in embryos developing in the womb led to a rethink.

Scientists learned stem cells which build the heart in the embryo are present in adults, but dormant.

The breakthrough discovery was that a peptide — a protein building block — called thymosin beta 4 (Tbeta4) which is normally active in the embryo could “re-awaken” the adult stem cells.

Scientists found they could “prime” the hearts of healthy mice for repair by injecting them with Tbeta4.

A “booster” dose of the peptide after a subsequent heart attack reactivated the stem cells and marshalled them into action. Not only did they build new heart muscle, but the cells were electrically “bonded” with existing muscle and able to contract in sync with the rest of the organ.

The results were published online in the journal Nature.

Researchers are looking at ways of tweaking the process to make it more efficient — possibly by finding more powerful alternative molecules with a similar effect to Tbeta4.

At a conservative estimate, they believe a practical treatment could be available in 10 years.

This might be an injection or a pill given to people known to be at risk of a heart attack. They could be patients who suffer from angina chest pains, individuals with high blood pressure or high cholesterol, or those whose close relatives have had heart trouble.

Study leader Professor Paul Riley, from the UCL Institute of Child Health, said: “I could envisage a patient known to be at risk of a heart attack — either because of family history or warning signs spotted by their GP — taking an oral tablet, along the lines of a [cholesterol lowering] statin, which would prime their heart so that if they had a heart attack, the damage could be repaired.”

Increasing numbers of people are surviving heart attacks, but then living with the debilitating effects of damage-induced heart failure.

Heart failure occurs when the heart can no longer pump sufficient blood around the body, so that even walking a few steps can be exhausting.

Boosting heart performance even a little would make all the difference, said Prof Weissberg.

“You may turn a patient from somebody who’s breathless and gasping for their breath while they’re sat in a chair to somebody who can sit comfortably in a chair,” he said. “A relatively small improvement in heart performance will have a major impact on quality of life and that’s the real hope here.”

The treatment might also work when administered for the first time straight after a heart attack, rather than at an earlier stage.

However, it does not offer hope for patients with inherited heart failure conditions such as cardiomyopathy caused by faulty genes.

Prof Riley’s team is now investigating whether the stem cells can be stimulated even further by other molecules or drugs that have already been developed.

One US biotech company, RegeneRX, has already produced a number of experimental Tbeta4-based treatments, including a skin gel to promote wound healing, and eye drops for corneal conditions.