In the aging orchestra of the body, every musician once played their part cleanly. With age, some musicians do not leave the stage but stay and start playing out of tune, and so loudly that they drown out their neighbors. These cells, which have stopped dividing but have not died, release dozens of inflammatory molecules, and this noise accelerates the aging of healthy tissues. Scientists have long sought a way to calm such musicians without throwing them out of the orchestra, because completely removing senescent cells can be risky.
The authors of a new study tried an approach that can be compared to a short rehearsal under a strict conductor. They briefly switched on in senescent cells four proteins known as Yamanaka factors, which are capable of turning any cell back into a stem cell. But instead of a full conversion, they gave only short pulses: three times for two days over six days. The second option was chemical: the cells were treated with a cocktail of two substances, tranylcypromine and RepSox.
The result turned out to be unexpectedly elegant. The cells did not return fully to a young state and did not start dividing again, but their behavior changed: the inflammatory noise subsided, the mitochondria (the cell's power stations) worked properly again, and the cell's readiness for programmed death, should it become dangerous, was restored. In other words, the conductor did not expel the old musicians but made them play more quietly and in better harmony, without letting them multiply again.
Senescent cells don't just passively grow decrepit: they actively release dozens of inflammatory molecules, and this "secretory phenotype" can accelerate the aging of neighboring healthy cells. In this study, the secretome of treated cells lost the ability to attract macrophages and induce senescence in neighbors, even though the cells themselves remained old by classical markers.
Not published on arXiv. Here are its page, the PDF and the formalization: you can check it yourself, not only read our account.