• Biotherapeutics

    Collaboration brings innovative regenerative therapies to babies with rare heart defect

A collaboration bringing together regional centers and advocacy groups to accelerate innovation and discovery is expanding, bringing clinical trials and expertise to more patients with Hypoplastic Left Heart Syndrome (HLHS) across the country. Led by Mayo Clinic’s Todd and Karen Wanek Family Program for HLHS, the collaboration began in 2017 and now has 10 members. Nine are hospitals and one is an advocacy group for patients and families.

HLHS is a rare and complex form of congenital heart disease in which the left side of a child's heart is severely underdeveloped. Today, standard treatment for people with HLHS includes three staged surgeries that enable the right ventricle to pump blood to the entire body. While many patients are able to live relatively normal lives as a result, there's often a need for treatment later in life. Approximately half of all patients will still need a heart transplant by age 10. 

“The consortium allows for a decrease in the amount of time from research and discovery to the clinical application of innovative cell-based therapies,” says Tim Nelson, M.D., Ph.D., director of the Todd and Karen Wanek Family Program for Hypoplastic Left Heart Syndrome.

The program works with hospitals across the U.S. to develop innovative cell-based research opportunities to transform the lives of people living with HLHS.

Regenerative medicine strategies have the potential to be an additional treatment for the management of critical congenital heart disease. Using stem cells of different types and from various sources — including autologous cells (from the patient's own body) — regenerative therapies may stimulate cardiac tissue to grow stronger and heal faster after surgery. 

Consortium members include Children's of Alabama, Children's Hospital Colorado, Children's Hospital Los Angeles, Children's Minnesota, The Children's Hospital at OU Medicine, Children's Hospital of Philadelphia, Cincinnati Children's, Mayo Clinic, and Ochsner Hospital for Children, as well as the advocacy group Sisters by Heart.

To date, 71 patients have been treated on four regenerative therapy clinical trials sponsored by the program. A Phase IIb study is currently open at six hospitals across the U.S.  During the second of three surgeries to repair the heart, stem cells from the baby’s own umbilical cord blood are injected into the heart muscle to help it grow stronger. New studies are in development to include other single ventricle-dependent heart defects, as well as to use stem cells during other planned surgeries. 

“By entering into this collaboration, we are making it possible for all children with HLHS to be able to participate in groundbreaking cell-based treatments, no matter their location,” says Dr. Nelson.

To learn more, visit the Mayo Clinic’s Todd and Karen Wanek Family Program for Hypoplastic Left Heart Syndrome website.


The HLHS Program is a highly comprehensive program advancing causes and cures for congenital heart disease, in particular hypoplastic left heart syndrome. The program takes a multifaceted research approach that includes imaging and outcomes, human genetics, and regenerative medicine. The Center for Regenerative Medicine is a champion of regenerative approaches to medical conditions such as those within the HLHS Consortium.