A research paper titled “Strehler-Mildvan correlation is a degenerate manifold of Gompertz fit” by the scientific team of a biotech company Gero has been published in the new issue of Journal of Theoretical Biology. It states that Strehler-Mildvan correlation has no real biological reasoning behind it and, therefore, there are no limitations to anti-aging interventions.
Strehler-Mildvan (SM) correlation was reported in 1960 in a now-famous and very well cited Science paper. It relates to the Mortality Rate Doubling Time (MRDT) and Initial Mortality Rate (IMR), two parameters of Gompertz mortality law. The original paper does not only introduce the empirical correlation, but also provides a sophisticated theory of aging behind it that is widely accepted among researchers. It says that if the mortality rate is reduced by any interventions at an earlier age, the MRDT goes down, i.e aging accelerates. This hypothesis leads to obstructions to anti-aging therapies development and makes optimal aging treatments impossible. Over years, quite a few researchers expressed doubts whether there was any biological meaning behind this correlation or not.
Gero team prefers to use evidence based science approach over machine learning techniques for anti-aging therapies design, focused on physical reasoning behind mortality dependence on biologically available signals, ranging from gene expression to locomotor activity. Trying to determine physical processes behind Strehler-Mildvan correlation, Dr. Peter Fedichev and his team noticed the fundamental disagreement between analytical considerations and possibility of SM correlation for Gompertz mortality law. In the paper, they showed that SM correlation arises naturally as a degenerate manifold of Gompertz fit.
Explaining these findings, Dr. Fedichev said: “We worked through the entire life histories of thousands of C.elegans that were genetically identical, and the results showed that this correlation was indeed a pure fitting artifact.” The problem is not as complicated for worm experiments, though it gets pretty tough if humans are involved (the ratio of Gompertz slope to IMR is too large). Thus it seems like SM correlation is an artifactual property of the fit, applied in a limit where the fit does not work, rather than a biological fact. Peter said, “Elimination of SM correlation from theories of aging is good news, because if it was not just negative correlation between Gompertz parameters, but the real dependence, it would have banned optimal anti-aging interventions and limited human possibilities to life extension.”