New stem cell patches could repair babies’ heart defects permanently

British researchers are developing patches made of stem cells to repair congenital heart defects — and if they work as hoped, the patches could eliminate the need for thousands of children to undergo repeated heart surgeries throughout their lives. 

The challenge: Congenital heart defects — problems with the structure of the heart, such as holes or improperly sized valves — are the most common type of birth defect, affecting about 1% of newborns.

Every year in the US, about 10,000 babies are born with congenital heart defects so severe that they won’t survive without heart surgery or some other intervention in their first year of life — a surgeon might need to repair a hole with a patch, for example, or replace a faulty heart valve.

“We are trying to create living tissue … that will grow with the child.”

Massimo Caputo

Sometimes a child’s immune system will reject these foreign materials, and they’ll need to undergo surgery again, in as little as a few months. Even if that doesn’t happen, surgeons will need to replace the materials with larger versions as the child grows.

Each of these surgeries can mean weeks in the hospital, an increased risk of infection, and immeasurable stress on the child and their loved ones. 

The patient: Massimo Caputo, a professor of congenital heart surgery at the University of Bristol, is now developing a better kind of patch for heart defects, inspired by his treatment of an infant named Finley.

About two years ago, when Finley was just four days old, he underwent surgery at Bristol Royal Hospital for Children to repair a congenital heart defect. There were complications following the surgery, though, and the baby was left reliant on machines to keep his heart pumping.

When Finley was two months old, doctors told his parents there was nothing else they could do to help him. That’s when Caputo reached out to propose injecting donated stem cells right into Finley’s heart — something that had never been done before. 

“[Caputo] warned us that he couldn’t predict what the outcome would be,” said Melissa Hudd, Finley’s mother. “But we had absolutely nothing to lose. We had to try and give Finley every possible chance to live.”

Caputo was given permission to perform the surgery under compassionate grounds, and Hudd said she started to see a change in her son within two weeks. At six months, he went home from the hospital for the first time, reliant only on a machine that helps him breathe at night.

“We can’t thank Massimo enough,” said Hudd. “I believe, if it wasn’t for the stem cell treatment, then Finley wouldn’t be here with us today.”

Looking ahead: Caputo is now using funding from the British Heart Foundation (BHF) to develop patches to repair congenital heart defects using stem cells sourced from donated placentas. 

These cells can be 3D bioprinted into whatever shape and size is needed to repair a valve abnormality or mend a hole. After the patch is sewn into place via surgery, the cells should help repair the child’s heart tissue — without putting them at risk of rejection.

“We are trying to create living tissue, whether it’s a valve or a blood vessel or a patch, that will grow with the child, and that does not deteriorate,” said Caputo. 

“It could offer a solution that means their heart is mended once and forever in a single operation, preventing people from facing a future of repeated surgeries and giving them the gift of a happier and healthier life,” added Sonya Babu-Narayan, associate medical director at the BHF.

The stem cell patches have already worked effectively and safely in animals, and Caputo hopes to launch clinical trials within the next two years.

“The stem cell plasters Massimo is now developing sound incredible,” said Hudd. “If they could give the gift of life and save other families from the emotional turmoil of their children having repeated open-heart surgeries, then that would be life-changing.”

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