A theory suggesting that young organs could rejuvenate older recipients has been challenged by new research. The study, led by Jesse Poganik at Brigham and Women’s Hospital in Boston, found that transplanted hearts, regardless of the donor’s age, quickly adopt the biological age of the recipient.
The idea that young organs might reverse aging gained traction from experiments where young and old mice were physically connected, resulting in the rejuvenation of the older mice. However, Poganik’s team discovered that this effect doesn’t translate to organ transplants.
Mice and human heart transplants reveal age adaptation
In the study, mice received a second heart implanted in their necks, allowing for comparison with their original hearts. Some young mice received middle-aged hearts, while some middle-aged mice received young hearts. Contrary to expectations, the transplanted hearts adopted the biological age of the recipient, with young hearts aging and old hearts rejuvenating.
This finding was supported by data from human heart transplants. Heart tissue samples from recipients, stored for decades, showed that donor hearts, regardless of age, quickly matched the biological age of the recipient.
The research suggests that the recipient’s body environment, possibly influenced by the immune system, plays a significant role in determining the biological age of the transplanted organ.
Implications for transplantation and aging research
Poganik’s findings could encourage the use of older donor hearts, which are often discarded due to assumed inferior function. This is particularly relevant as machines preserving organs before transplantation are already improving the viability of older organs.
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The study also highlights the complexity of aging. If organs age differently by various measures, understanding the full picture of biological aging becomes more challenging. This complexity makes the complete reversal of aging an unlikely prospect, according to Poganik.
While some aspects of biological age may be reversible, others likely are not. The research shows the detailed nature of aging and the limitations of organ transplantation as a means to achieve rejuvenation.
The study was published online at bioRxiv, contributing to the ongoing exploration of aging and its potential reversal.
The Role of the Immune System in Organ Aging
The study’s findings suggest that the recipient’s immune system may play a key role in determining the biological age of a transplanted organ. João Pedro de Magalhães, an aging researcher at the University of Birmingham, proposes that immune cells circulating in the blood could influence aging markers in the new organ.
Implications for Organ Donation and Aging Research
This finding is particularly relevant as machines used to preserve organs before transplantation are already improving the viability of older organs.
