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April 29, 2025
A pioneering team at Children’s Hospital Los Angeles (CHLA) has become the first in the world to demonstrate the potential of using genetically engineered pig hearts as a temporary “bridge” to heart transplant for critically ill infants. This innovative approach could offer new hope to babies with severe heart conditions, particularly those suffering from single-ventricle heart disease-a group with extremely limited options and high mortality rates while waiting for a suitable human donor.
Addressing a Critical Need
While ventricular assist devices (VADs) have been used to support many patients awaiting heart transplants, they are often ineffective for infants with single-ventricle heart disease. Only about 30% of these babies survive three months on a VAD, largely due to complications such as strokes, bleeding, and infections. “A machine cannot constantly adapt to the physiology like an actual heart,” explained Dr. John David Cleveland, lead researcher and congenital heart surgeon at CHLA’s Heart Institute.
The new research suggests that genetically engineered pig hearts could serve as a more adaptive and potentially safer temporary solution, giving these vulnerable infants a better chance of surviving until a human heart becomes available. Dr. Cleveland added, “Not only could the outcomes be better, but a pig heart could potentially allow babies to go home while they wait for a human heart, as opposed to being connected to a VAD in the hospital.”
Promising Preclinical Results
Supported by an R33 Catalyze grant from the National Institutes of Health, the CHLA-led team has spent five years developing and testing this approach. In their preclinical studies, they transplanted genetically modified pig hearts into 14 young baboons. Eight of these baboons survived for several months, with one living for an unprecedented 620 days-nearly 21 months. This marks the longest survival of a nonhuman primate with a pig heart to date.
The team also achieved a world-first by successfully replacing a functioning pig heart xenograft with a same-species heart in two baboons, demonstrating the feasibility of transitioning from a pig heart to a human heart when a suitable donor becomes available.
Advances in Science and Medicine
The field of xenotransplantation has advanced significantly since the 1984 case of “Baby Fae,” who received a baboon heart but survived only 21 days due to organ rejection. Today’s genetically engineered organs are designed to be more compatible with the human immune system, and new immunosuppressive medications, like the investigational anti-CD40L antibody tegoprubart, are improving the chances that foreign organs will be accepted by the body.
The researchers are also working with Yucatan miniature swine, a breed that grows more slowly and is better suited for pediatric patients. Intriguingly, the team’s studies suggest that infants may be more likely than adults to accept pig organs, as young children lack the antibodies that typically trigger rejection.
Looking Ahead
While the research is still in its early stages, the results are promising. “We still have more research to do. But our hope is that we can eventually offer these babies a much better chance to live,” said Dr. Cleveland.
If successful, this approach could revolutionize the way critically ill infants are supported while waiting for a heart transplant, potentially allowing them to spend more time at home and improving their chances of survival.
Disclaimer:
This article is based on preliminary research findings presented by Children’s Hospital Los Angeles and published by Medical Xpress on April 28, 2025. The use of genetically engineered pig hearts as a bridge to transplant in human babies is still in the experimental stage and has not yet been approved for clinical use. Further research and regulatory review are necessary before this approach can be considered a standard treatment. For more details, see the original article at Medical Xpress.
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