What if we could rejuvenate?

The secret of youth would not be found in the fountain of youth or the philosopher’s stone, but in proteins and cells. These are more specifically the proteins involved in the onset of embryonic development and induced pluripotent stem cells, or more simply iPS (for “induced pluripotent stem cells”).

It is to the Japanese researcher Shinya Yamanaka that we owe the discovery of these cells, which earned him the Nobel Prize for Medicine in 2012. His achievement: “take virtually any cell from an adult and genetically reprogram it to make it pluripotent, i.e. capable of infinitely multiplying and differentiating into all the cell types that make up an adult organism, such as a embryonic stem cell”exposes Inserm.

Reverse aging without inducing pluripotency

It is on the basis of this work that scientists from the stanford university medical school (USA) conducted their research. “When iPS cells are made from adult cells, they become both younger and pluripotentexplains Vittorio Sebastiano, an assistant professor at Stanford University, in a article published on the institution’s website. We wondered for a while if it might be possible to simply turn the aging clock back without inducing pluripotency..”

The researcher and his colleagues had arrived at this questioning during previous work. They created iPS cells from adult cells by repeatedly exposing them for two weeks to proteins important in early embryonic development. A process that had been made possible by the daily introduction of short-lived messenger RNA (ribonucleic acid) into adult cells. These messengers contained the instructions to produce “Yamanaka proteins”, used in the reprogramming of cells into iPS cells. Result: the proteins had pushed the cells back to a younger stage, while making them pluripotent.

One and a half to three and a half year younger cells

During their news study — whose results have been published in the scientific journal Nature — the researchers exposed the human cells to the Yamanaka proteins for only four days instead of two weeks, so as not to induce pluripotency. This paid off: cells from older people showed signs of age reversal and were younger, on average one and a half to three and a half years, than untreated cells, also from people elderly. The peak is at three and a half years for skin cells and seven and a half years for blood vessel cells.

“Our latest and most important experiment was conducted on muscle stem cellsexplains Vittorio Sebastiano. Although they are naturally endowed with the ability to self-renew, this ability diminishes with age. We asked ourselves: can we also rejuvenate stem cells and have a long-term effect?” The researchers therefore treated stem cells from old mice, before reintroducing them into the animals’ bodies. Result: they regained the muscle strength of younger mice.

“Potential therapeutic implications for aging”

Researchers are now exploring the possibility of treating cells and tissues without removing them from the body. Although he assures that he remains “a lot of work to do”, Vittorio Sebastiano is optimistic and hopes that one day it will be possible to “reboot entire tissues”. In their study, the researchers estimate that their results “represent a significant advance towards the goal of reversing cellular aging and have potential therapeutic implications for aging and age-related diseases.”