Scientists in California, Colorado receive grants to study heart transplants in children

DALLAS, April 25, 2022 — Scientific research teams in California and Colorado have been awarded nearly $1.4 million in grants to study ways to improve pediatric heart transplant outcomes. These two research awards mark the latest round of funding for a joint $3 million scientific research initiative between the American Heart Association, the world’s leading voluntary organization focused on heart and brain health and research for all, and Enduring Hearts, a non-profit organization dedicated to funding innovative research aimed at improving the lives of children living with transplanted hearts.

The announcement comes during National Pediatric Transplant Week, April 24-30, 2022.

According to Enduring Hearts, more than 450 children undergo a heart transplant in the U.S. each year. Although medical advances have improved over the years, many of these children and their families still face a lifetime of challenges. More than 1 in 4 pediatric heart transplants will fail within five years, largely due to some type of organ rejection. The average pediatric heart transplant lasts only 17 years and currently less than 5% of those children will have the chance for a second transplant.

The two projects, each receiving nearly $700,000 for their three-year research studies, will focus on identifying how certain drugs work in improving heart transplant outcomes in children and how changes to medication can improve survival among these children.

  • Reducing Transplant Graft Dysfunction Through Targeted Immunosuppression at Stanford University School of Medicine in Stanford, Calif. – Led by Karim Sallam, M.D., an assistant professor of medicine, and Seth Hollander, M.D., a clinical associate professor and medical director for pediatric heart transplantation, this team will study how different immunosuppressant drugs that must be taken by transplant recipients affect the heart muscle.

The researchers will use a technology that can produce small human heart tissue clusters in the lab. They’ll treat the heart clusters with commonly used drugs that suppress the immune system and evaluate changes that cause the transplanted heart to not work properly (like scar tissue build up). They’ll also look for changes inside the cell that may be causing long term damage. This information can be combined with human heart tissue samples to understand how each medication affects the heart muscle. Through this study, the team hopes to determine if one drug is better at preventing damage to the transplant graft, one of most common reason for a transplant death or need for a new transplant. The results can also provide insight to help develop new medications to prevent damage to transplanted hearts.

  • Circulating Unconventional T Cells in Pediatric Heart Transplant Recipients: From Pathogenesis to Biomarker at Children’s Hospital Colorado and the University of Colorado School of Medicine in Denver – Led by Stephanie Nakano, M.D., an assistant professor of pediatrics, Jordan Abbott, M.D., an assistant professor of pediatrics and Laurent Gapin, Ph.D., a professor of immunology and microbiology, this team will study how much medication is optimal for the best outcomes in children who undergo heart transplants.

After a heart transplant, children need to take medications for the rest of their lives to prevent the immune system from attacking the transplanted heart. It is unclear exactly how much medication is needed and the exact amount can vary from person to person. If the immune system is suppressed too much, this may result in infections or cancer. If the immune system is not suppressed enough, this can cause damage to the transplanted heart. This team will be studying a recently identified population of immune cells called MAIT cells that are thought to play a unique role in the immune system. Their goal is to learn more about these immune cells and use them as a sensor to adjust the amount of medication each child needs. This may improve the lives of children with heart transplants by protecting the transplanted heart with fewer medication side effects.

“This cutting-edge research is crucial to improving the lives of children who have been given a new chance at life through the innovation of heart transplantation,” said American Heart Association President Donald M. Lloyd-Jones, M.D., Sc.M., FAHA, chair of the department of preventive medicine, the Eileen M. Foell Professor of Heart Research and professor of preventive medicine, medicine and pediatrics at Northwestern University’s Feinberg School of Medicine in Chicago. “We are excited about the immediate impact the findings from these projects can potentially make in real-world treatment for many of our most vulnerable survivors of heart disease.”

“As a result of this collaboration with the American Heart Association, Enduring Hearts is able to bring new science-based advances to address the unique needs of all children living with a heart transplant and their families," said Robert Boucek, M.D., Enduring Hearts Scientific Board Chair.

These new research projects will begin work on July 1, 2022.

About the American Heart Association

The American Heart Association is a relentless force for a world of longer, healthier lives. We are dedicated to ensuring equitable health in all communities. Through collaboration with numerous organizations, and powered by millions of volunteers, we fund innovative research, advocate for the public’s health and share lifesaving resources. The Dallas-based organization has been a leading source of health information for nearly a century. Connect with us on heart.orgFacebookTwitter or by calling 1-800-AHA-USA1.

The American Heart Association has funded more than $4.9 billion in cardiovascular research since 1949. The Association receives funding primarily from individuals; foundations and corporations (including pharmaceutical, device manufacturers and other companies) also make donations and fund specific Association programs and events. The Association has strict policies to prevent these relationships from influencing the science content. Revenues from pharmaceutical and biotech companies, device manufacturers and health insurance providers and the Association’s overall financial information are available here.

About Enduring Hearts

Enduring Hearts is a national nonprofit that launched in 2013 to fund innovative research globally to improve longevity and the quality of life for children living with a heart transplant.  Enduring Hearts has funded over $7.5M in targeted pediatric heart transplant research. Enduring Hearts provides a variety of programs to offer both tangible and educational support to families during their transplant. Connect with us on, Facebook or Twitter.


For Media Inquiries:

American Heart Association: Cathy Lewis,; 214-706-1324

Enduring Hearts: Carolyn Salvador:; 404-849-2257

For Public Inquiries: 1-800-AHA-USA1 (242-8721) and

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