Mending Broken Hearts

How regenerative medicine can repair heart defects in children 

It’s an unimaginable scenario for an expectant parent: A routine ultrasound reveals your unborn baby has a life-threatening heart defect. Doctors can likely repair his fragile, malformed heart, but your child will face years of difficult operations and the possibility of lifelong complications.

This is a reality that patient families face every day at Children’s Hospital Colorado. But what if there was a better, less invasive way to repair congenital heart defects — one that would allow children to safely heal without multiple open heart surgeries? 

Imagine if doctors could use emerging technologies to 3D print the damaged components of a patient’s heart — making valves, ventricles, even the entire organ — and then quite literally bring those parts to life by infusing them with the child’s own healthy stem cells. These bioengineered parts would then be implanted in patients and become living, functional tissue, helping to repair heart defects permanently.

You might think this sounds like something out of a science fiction novel. And yet in a laboratory on the Anschutz Medical Campus, these astonishing innovations are already well on their way to becoming a reality.

Regenerating hearts

Congenital heart defects are the most common form of birth defects. Children’s Colorado’s patient survival rates are among the best in the nation, but many children still face a long, painful road to recovery. Tragically, despite doctors’ best efforts, some die prematurely.

With the help of donors, the future is looking brighter for children born with heart problems. Children’s Colorado physician-scientists are on the brink of new breakthroughs in regenerative medicine that could radically change the way we repair congenital heart defects. This promising area of research seeks to repair or replace damaged tissue with living, functional cells.   

“For 30 years, there hasn’t been any real technological change to how these defects are repaired,” says Dr. Jeffrey Jacot, a researcher with the University of Colorado Department of Bioengineering. “I think regenerative medicine is going to change that.”

Creating living tissue

Pediatric heart surgeon Dr. James Jaggers, Co-Medical Director of the Children’s Colorado Heart Institute and The Barton-Elliman Chair in Pediatric Cardiothoracic Surgery, often uses synthetic patches to correct conditions like hypoplastic left heart syndrome and other heart defects. Synthetic patches are currently the best available option, but they have many limitations.

“The problem with synthetic patches is that they aren’t living,” Dr. Jaggers said. “They don’t contract like the human heart does. They don’t have electrical activity like the human heart. And they don’t grow with children as they get older.”

Repairing defects with synthetic material means children typically have to undergo multiple open-heart surgeries throughout their childhood to fully repair a defect. Dr. Jaggers believes that advances in regenerative medicine could change that.

Here’s how it would work: When a baby is born with a congenital heart defect, doctors would harvest the child’s amniotic stem cells during delivery. Those cells could then be genetically transformed into the variety of cells that make up the human heart. Researchers such as Dr. Jacot could then weave those cells into a so-called “living” heart patch, which Dr. Jaggers could implant to repair the child’s heart.

Unlike a synthetic heart patch, the living patch would beat like a real heart and grow as the patient grows.

“Living heart patches will give full cardiac function back to these infants with heart defects, possibly allowing them to avoid the need for multiple operations,” said Dr. Jacot. 

Researchers believe these remarkable innovations could benefit patients within five years. Much of the technology already exists, and the team has proven that they can generate beating heart cells from amniotic fluid. For patients like Oliver, it’s feasible — even likely — that tissue engineered in a lab on the Anschutz Medical Campus will soon help to cure their damaged hearts, potentially eliminating the need for future surgeries. 

Eventually, with support from visionary philanthropists, Dr. Jaggers and others hope to take the research beyond living patches to rebuild entire chambers of the heart. These advancements could have dramatic implications for heart transplant patients. Gifts from generous donors like Carol and Tom Fullerton, the Millisor family, The Boedecker Foundation and many others make the groundbreaking research at the Children’s Colorado Heart Institute possible.

“Someday we may be able to 3D print heart components and infuse them with living cells harvested from the patient,” said Dr. Jaggers. “We could then implant those parts to repair defects.”

A history-making surgery

These life-saving discoveries are becoming closer to reality. Just recently, Children’s Colorado joined a consortium led by the Mayo Clinic to advance cell-based research for congenital heart defects. The partnership is already yielding promising results.

“Earlier this year, a mother delivered a baby with hypoplastic left heart syndrome at our hospital. She allowed us to collect the baby’s cord blood to send to Mayo Clinic for processing,” said Dr. Jaggers.

A few months later, during the patient’s second heart surgery, Dr. Jaggers injected the baby’s stem cells directly into the baby’s heart muscle in a first-of-its-kind, history-making procedure aimed at strengthening the child’s heart.

“Early results show that the function of the heart is pretty significantly improved in the short-term after the injections of these stem cells,” said Dr. Jaggers.

For many children with complex heart defects, the organ may eventually simply “wear out.” The ultimate goal of stem cell injections is to strengthen and improve heart function to the point that some patients can delay — or even avoid — a heart transplant.

It’s a trailblazing concept — one that Dr. Jaggers calls a “game changer” for his patients. With ongoing philanthropic support, Children’s Colorado researchers will continue to develop life-saving breakthroughs that today’s innovators are only beginning to imagine.