A remarkable report was published on July 11, 2018 which some readers may have heard about. In this paper, James Kirkland (at Mayo Clinic) and his colleagues report in the journal, Nature Medicine, on a series of interesting experiments involving senescent cells in mice.
First, they tested the effects of transplanting a small number of senescent cells into young mice. These senescent cells caused a “persistent physical dysfunction”, and appeared to spread cellular senescence to other tissues. When senescent cells were transplanted into old mice, they observed similar results, as well as a shortening of the remaining lifespan in the old animals. These results suggest that the presence of senescent cells do indeed have a deleterious effect on function and lifespan, at least in mice.
Second, the research team administered to old mice, two chemicals known for their ability to eliminate senescent cells—a class of chemicals called “senolytics”. The two chemicals used were dasatinib and quercetin. Intermittent treatment with these two senolytics were associated with some remarkable effects, including:
- A reduction in naturally occurring senescent cells, and
- An increase in the remaining lifespan of the animals (compared to controls).
Moreover, when given to young mice who received a transplant of senescent cells, dasatinib and quercetin reversed the physical dysfunction associated with the transplant.
These findings are remarkable. There are not many interventions known to improve physical function and extend remaining lifespan when given to mice in old age.
Finally, there is a reasonable cause for concern over the idea of eliminating senescent cells in aging humans. In addition to being involved in aging, cellular senescence is also known to be involved in wound healing and organism development. Some researchers have expressed concern that eliminating senescent cells in older people might inhibit tissue maintenance and repair. The consistently positive results reported in the current study suggest that, at the very least, using this particular senolytic cocktail intermittently appears to have multiple benefits in old mice, and suggest that senolytics may be worth testing in aging humans.