An experiment conducted by the lab of Berkeley bioengineering professor Irina Conboy showed that a single transfusion of blood from older mice to younger mice triggered cellular senescence in the younger animals.
Cellular senescence—when damaged cells cease to grow or reproduce—is a normal biological process. However, the accumulation of senescent cells as we age is associated with organ damage and chronic disease.
In the lab experiment, younger mice showed an increase in senescent cells in the kidneys, liver, and muscles two weeks after the transfusion. The young mice had also become weaker, as observed in strength tests.
The experiment shows that cellular senescence is not just a response to age or stress. It also provides new insights into the potential and limitations of therapies such as senolytic drugs that clear senescent cells from the body.
“Cell senescence is only part of the process of aging,” Conboy told the magazine New Scientist. “That opens new horizons and helps explain why senolytics so far in clinical trials were less successful than people hoped.”
Still, senolytics may improve health overall. In the abstract of the study, published in Nature Metabolism in July, the researchers conclude that “clearing senescence cells that accumulate with age rejuvenates old circulating blood and improves the health of multiple tissues.”
Humans looking for a readily available fountain of youth in the form of young blood will likely be disappointed. In 2019, the U.S. Food and Drug Administration stated that “there is no proven clinical benefit of infusion of plasma from young donors.” The procedure is currently strongly discouraged in the United States.