Since 2007, a handful of research teams across the world have been capable of reprogramming human adult cells into induced pluripotent cells (iPSC), which have similar characteristics and potential to human embryonic stem cells (hESC). This kind of reprogramming makes it possible to reform all human cell types without the ethical restrictions related to using embryonic stem cells. Until now, research results demonstrated that senescence (the final stage of cellular aging) was an obstacle blocking the use of this technique for therapeutic applications in elderly patients. INSERM (France) scientists, led by Jean-Marc Lemaitre, have overcome this obstacle. The researchers have successfully rejuvenated cells from elderly donors, some over 100 years old, thus demonstrating the reversibility of the cellular aging process.  The team applied a “cocktail" of six factors, to senescent cells, programmed into functional iPSC cells, and found that they re-acquired the characteristics of embryonic pluripotent stem cells. In particular, they recovered their capacity for self-renewal and their former differentiation potential, and do not preserve any traces of previous aging. Writing that: “Here we demonstrate, using an optimized protocol, that cellular senescence is not a limit to reprogramming and that age-related cellular physiology is reversible,” the study authors submit that: “we show that our iPSCs generated from senescent and centenarian cells have reset telomere size, gene expression profiles, oxidative stress, and mitochondrial metabolism, and are indistinguishable from hESCs. [We] show that senescent and centenarian-derived pluripotent stem cells are able to redifferentiate into fully rejuvenated cells. These results provide new insights into iPSC technology and pave the way for regenerative medicine for aged patients.