DURHAM, N.C. — Doctors at Duke Health say they have performed a heart transplant on a 6-month-old boy in a way that could change how organ transplants are done in the future.
The new technique could make transplants more durable and successful by reducing the body’s instinct to reject the donated organ and the need for medications to prevent rejection.
That’s because along with the tiny donated heart, Easton Sinnamon also received cultured tissue from the thymus gland of the same donor. The thymus stimulates production of T cells that fight off foreign substances in the body, and doctors expect that by implanting tissue from the donor’s thymus Easton’s immune system will recognize the heart as his own.
Dr. Joseph Turek, Duke’s chief of pediatric cardiac surgery and a member of the team that performed the procedure, said it could be repeated with other organs such as kidneys and livers.
“This could affect thousands and thousands of patients who need transplants down the road,” he said in a virtual press briefing Monday.
A congenital heart defect
Easton was born last winter with a congenital defect that kept one of his heart valves from closing. The problem had been diagnosed before he was born, so Easton’s parents, Kaitlyn and Brandon Sinnamon, were prepared for his open heart surgery when he was just 5 days old.
The surgery was only partly successful, and doctors decided Easton would need a new heart if he was going to survive.
Doctors also learned that Easton’s immune system was not functioning properly, preventing him from fighting off infections. That made him a candidate for a process developed at Duke in which thymus tissue is cultured and implanted in children born without a thymus gland.
So Easton became the first patient in the world to receive both a new heart and thymus tissue from a single donor. The heart transplant took place at Duke University Hospital last Aug. 6; two weeks later his defective thymus was replaced by cultured thymus tissue from the heart donor.
Easton has been receiving medications to suppress his immune system, to prevent his body from rejecting the heart. But Turek said doctors expect the new thymus tissue will help his body tolerate the new organ, allowing them to wean him off those medications in the coming year.
“I think he has a good chance of developing tolerance based upon what his T cells are doing right now,” Turek said.
Speaking from their home near Asheboro on Monday, Kaitlyn and Brandon Sinnamon took turns holding Easton and describing what it was like to bring him home after months in the hospital. He still receives food and medications through a feeding tube but has the smiling, chubby face of a healthy 1-year-old.
“The way that he was in the hospital, it was an amazing feeling bringing him home,” Brandon said.
‘This transplant could last decades’
A typical transplanted heart remains functioning for only about 10 to 15 years, in part because of the body’s attempts to reject it, Turek said. The medications needed to prevent that from happening also take a toll on the body, causing kidney problems, infections and sometimes cancer.
The hope is that transplanting new thymus tissue along with the organ will help the body accept the organ without years of medications.
“The idea is if you don’t have all these episodes of rejection, potentially this transplant could last decades,” he said.
More research is needed to learn how to make these transplants work in patients with healthy immune systems. The key, Turek says, is the process of culturing thymus cells that Duke licensed to Durham-based Enzyvant Therapeutics and which allows the body to essentially form a new immune system.
Turek said he doesn’t think it will be long before doctors are able to repeat Easton’s experience with other patients, including those with healthy immune systems.
In a video put out by Duke, Kaitlyn Sinnamon spoke about how her son’s ordeal may help others someday.
“I hope that as he gets older he gets to be proud of his scars,” she said, “and know that he not only got to save his own life but got to save other people’s lives as well.”
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