Archive · 29 Sep 2026
Young Bodies May Rejuvenate Transplanted Hearts, Preliminary Study Finds
Scientists studied whether a transplanted heart changes as it lives inside a new body.
They used hearts from young, middle-aged, and old mice.
Each heart was placed into mice of different ages.
After several months, the hearts showed signs of becoming more like the age of their new bodies.
Young hearts in older mice appeared to age faster.
Older hearts in young mice showed signs of becoming younger biologically.
Researchers also examined 11 human heart transplants with large age differences.
Those cases showed patterns similar to the mouse experiments.
The study is still a preliminary report and scientists do not yet know exactly why this happens.
Harvard University researchers reported that transplanted hearts can shift biologically toward the recipient’s age.
In mice, young hearts aged faster in older bodies, while older hearts showed signs of rejuvenation in younger bodies.
Researchers studied hearts from mice aged three months, one year, and 1.5 years after transplantation.
The age-related changes were observed four to six months after transplantation through tissue and genetic analysis.
An analysis of 11 age-disparate human heart transplants at Brigham and Women’s Hospital showed similar effects, but the study has not yet been peer-reviewed.
- Who
- Researchers at Harvard University studied transplanted hearts in mice and examined 11 human transplant cases at Brigham and Women’s Hospital.
- What
- The study found that a transplanted heart’s biological age may shift toward the age of its recipient.
- When
- The mouse hearts were examined four to six months after transplantation; the report is preliminary and has not yet been peer-reviewed.
- Where
- The experiments were conducted in mice, while human transplant data came from Brigham and Women’s Hospital in Boston.
- Why
- Researchers aimed to understand how donor hearts adapt biologically after being placed in recipients of different ages.
- Study status
- Posted on bioRxiv and not yet peer-reviewed
- Researchers
- Researchers at Harvard University
- Animal model
- Mice aged three months, one year, and 1.5 years
- Main finding
- Donor-heart biological age shifted closer to the recipient’s age
- Human data
- 11 heart-transplant cases with significant age gaps
- Observation period
- Four to six months after transplantation in the mouse experiments
- Human hospital
- Brigham and Women’s Hospital in Boston