British researchers have developed a biodegradable gel to repair damage caused by a heart attack in a breakthrough that could improve the health of millions of survivors worldwide.

There are more than 100,000 hospital admissions every year due to heart attacks in the UK alone – one every five minutes. Medical advances mean more people than ever before survive, with 1.4 million Britons alive today after experiencing a heart attack. But hearts have a very limited ability to regenerate, meaning survivors are left at risk of heart failure and other health problems.

Now after years of efforts searching for solutions to help the heart repair itself, researchers at the University of Manchester have created a gel that can be injected directly into the beating heart – effectively working as a scaffold to help injected cells grow new tissue.

Until now, when cells have been injected into the heart to reduce the risk of heart failure, only 1% have stayed in place and survived. But the gel can hold them in place as they graft on to the heart.

“While it’s still early days, the potential this new technology has in helping to repair failing hearts after a heart attack is huge,” said Katharine King, who led the research backed by the British Heart Foundation (BHF). “We’re confident that this gel will be an effective option for future cell-based therapies to help the damaged heart to regenerate.

To prove the technology could work, researchers showed the gel can support growth of normal heart muscle tissue. When they added human cells reprogrammed to become heart muscle cells into the gel, they were able to grow in a dish for three weeks and the cells started to spontaneously beat.

Echocardiograms (ultrasounds of the heart) and electrocardiograms (ECGs, which measure the electrical activity of the heart) on mice confirmed the safety of the gel. To gain more knowledge, researchers will test the gel after mice have a heart attack to show they develop new muscle tissue.

The study is being presented at the British Cardiovascular Society conference in Manchester.

Prof James Leiper, an associate medical director at the BHF, said: “We’ve come so far in our ability to treat heart attacks and today more people than ever survive. However, this also means that more people are surviving with damaged hearts and are at risk of developing heart failure.

“This new injectable technology harnesses the natural properties of peptides to potentially solve one of the problems that has hindered this type of therapy for years. If the benefits are replicated in further research and then in patients, these gels could become a significant component of future treatments to repair the damage caused by heart attacks.”

Separate research being presented at the same conference found that obesity can drive hearts to fail and weaken their structure.

The largest study of its kind on 490,000 people found that those with a higher body mass index (BMI) and waist-to-hip ratio had about a 30% increased risk of heart failure. This risk occurred regardless of other risks for heart failure such as diabetes, high blood pressure and high cholesterol.

Dr Zahra Raisi-Estabragh, from Queen Mary University of London, who supervised the study, said: “We already know that obesity increases the risk of heart and circulatory diseases that can go on to cause heart failure. But now we have revealed that obesity itself could be a driver of hearts starting to fail.”