Young organs may not rejuvenate transplant recipients, study finds

Researchers at Brigham and Women's Hospital transplanted extra hearts into young and middle-aged mice and found the donor organ quickly adopted the recipient's biological age. Biopsies from human heart transplants showed the same pattern.

• Young hearts aged and old hearts rejuvenated inside the recipient
• Effect confirmed in decades of stored human heart biopsy samples
• Other organs and blood of the mice showed no changes after transplant
• Finding could expand use of hearts from older donors