Inevitable aging? You got it wrong!
Is that true that aging is inevitable? Drs Paul Nelson and Joanna Masel, the authors of a recent PNAS paper “Intercellular competition and the inevitability of multicellular aging”, claim that aging cannot be fought. The scientific team of a biotech company Gero focused on research against aging strongly disagrees with this conclusion.
Peter Fedichev, Ph.D., the author of a paper cited by Nelson and Masel in the original publication, explains why aging can be stopped.
Our colleagues make a good point, suggesting that competition among cells of a multicellular organism leads to its inescapable degradation and death. The most important example of this process is cancer cells outplaying other cells of a body and taking control over its resources until they cease to exist.
The original study proposes a very reasonable model describing how cellular composition of an organism evolve with age and concludes that aging is inevitable. At the same time, the authors acknowledge that the concept of negligible senescence “is not without theoretical justification” and cite our paper, suggesting that “gene networks can be indefinitely stable if cellular repair mechanisms are sufficiently effective”.
They point out that repair systems also break up with age, thus becoming less efficient in older organisms. We discuss this positive feedback loop in our work as the reason for the exponential increase of probability of death with age observed in most species. For instance, in humans aging manifests itself as the increasing all-cause-mortality risk that doubles every eight years (also known as Gompertz mortality law).
The thing is, repair systems come in many flavors and are certainly not limited to cellular repair mechanisms. Nelson and Masel specifically mention the immune system and cancer suppression genes, suggesting that “such mechanisms might significantly slow aging, perhaps even to negligible rates”. Their model “does not inform the magnitude of the age-related decline, only its inevitability”. By saying that they imply the possibility of a situation when the body cellular composition stabilizes, or, in other words, the organism does not age.
But even the absence of aging would not guarantee immortality. Studies of non-aging animals show that they still develop terminal diseases and eventually die of it. And yet these animals do not age in the commonly accepted way. Instead, they die young after a long life (naked mole rats survive for up to 28 years — eight times longer than mice of a same size). Their disease risks and mortality are age-independent.
There is no theoretical or practical reason why humans could not reach negligible senescence — a fancy way to say “stopped aging”. Instead, it is highly possible that prospective therapies would allow eliminating age-related changes, easing the burden of diseases and putting a break on the productivity decrease and human suffering associated with age. We will live longer while staying young, healthy and productive.
At Gero, we believe that engineering of negligible senescence in human populations is one of the most important technological and humanitarian problems of our time. We work closely with the most prominent minds in the field to find its solution.
