Transplanted hearts adopt recipient's biological age, studies find

September 25, 2026 at 02:00 PM1 min

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New research on heart transplants in mice and humans shows transplanted hearts quickly adopt the biological age of the recipient, regardless of the donor's age. The findings challenge the 'replacement' theory of longevity, which suggests young organs could rejuvenate older recipients. The study, led by Jesse Poganik at Brigham and Women's Hospital, used molecular aging clocks to assess biological age.

Key Facts

Jesse Poganik at Brigham and Women's Hospital in Boston led the study on heart transplants in mice.
In human heart transplants, most recipients are about 20 years older than their donors, according to hospital records assessed by Poganik.
The team used three molecular 'aging clocks' to estimate the biological ages of tissues and whole organisms in mice.
Previous work by other team members found that young mice receiving old hearts experienced a buildup of senescent cells in other organs.

The Study

Jesse Poganik and colleagues at Brigham and Women's Hospital performed heart transplants in mice to investigate whether young organs could rejuvenate older recipients. In the mouse experiments, some young adult mice received a heart from a middle-aged donor, while middle-aged mice received young hearts. The transplanted hearts were implanted in the neck, allowing scientists to compare the new hearts with the existing ones. The team used three molecular aging clocks to estimate the biological ages of tissues and whole organisms.

Findings

The aging clocks accurately predicted the chronological age of mice that did not receive new hearts. Poganik expected a reciprocal effect, such as young hearts benefiting older animals, but the results did not show this. In previous work by other team members, young mice that received old hearts experienced a buildup of senescent cells in their other organs. The new findings suggest that transplanted hearts adopt the biological age of the recipient, regardless of the donor's age.