Researchers from the renowned Mayo Clinic have succeeded in granting mice longer and healthier lives by deactivating worn-out senescent cells. The results of their study have been published in Nature this week. The findings could have significant implications for the way we will treat age-related morbidity in humans in the near future.
Senescent cells are cells that have lost their ability to divide due to ageing. As animals and people age, these cells start to accumulate in the body, where they release molecules that can be harmful for nearby tissue. Approximately 1 to 2 percent of our body cells turn senescent as we age. Senescent cells are suspected to contribute to all kinds of age-related health ailments, such as kidney failure and type 2 diabetes.
The researchers conducted an experiment in which middle-aged mice were treated to remove or deactivate these senescent cells. Compared to an untreated control group, the treated mice lived approximately 20 to 30 % longer, which constitutes a drastic increase in lifespan (the equivalent of reaching the age of 100 for humans). And not only did the treated mice live longer, by eliminating the senescent cells these mice also stayed healthier; they developed cancer at a later age, their kidneys functioned better, their hearts were more resilient to stress, they were less prone to develop cataract and they remained active and energetic at an old age.
Implications for humans
As stated before, the findings could have important implications for the human ageing process. If similar treatments could be successfully tailored for application in human subjects, this could potentially decrease the age-induced burden of disease. It has to be noted that the mice used in the experiment are not ordinary mice, but genetically altered specimens whose senescent cells were made particularly susceptible for elimination. Still, the researchers argue that in the near future it might be possible to use a therapy to target senescent cells in humans. While this does not imply immortality is within reach – as there are many other factors which contribute to the ageing process – it will still enable people to live longer and above all healthier lives on average.
Jan van Deursen, a molecular biologist at the Mayo Clinic in Rochester, Minnesota, states that the findings are particularly promising for treating patients with typical old-age health ailments linked to the accumulation of senescent cells, such as arthritis. Another interesting patient group could be people that have undergone chemotherapy for cancer, leading to an increase in senescent cells.
Australian professor of old age medicine Andrea Maier thinks that within a couple of years the first cautious clinical trials might take place with human subjects. She does warn that the expectations might be too high. Even though the results are promising, she argues that scientists are still trying to figure out where exactly the senescent cells are located in humans.