Article states they had fewer biomarkers of aging, and showed less age-associated obesity, fraility, and metabolic decline. So their "youth" period extended longer.
Actually the point of healthspan vs lifespan is made in the introduction -- it was a justification for using mice for this study, which have clear health phenotypes that are analogous to humans.
I'm basically skeptical of any longevity study in mice or yeast or C. Elegans because I think humans already have superior longevity factors over other animals because of our culture: we can live 3x reproductive age and still contribute to the survival of our descendants and our tribe.
Metabolic adaptations that prolong the life of mice might be just bringing them closer to where we are as opposed to something that would work for us.
Unmodified C elegans can certainly live to 3x reproductive age, fwiw. These are all simplistic model organisms by definition but many nearly identical proteins are found in humans and there’s value to studying their structure and function in a very well-known environment. I wouldn’t take it as “just delete IL11 and you’ll live to 130!” but the fact that it’s presented that way is more the fault of marketing departments and science writers.
The only significant, deleterious phenotype in il-11 KO mice is the inability to sustain pregnancy. So far it seems to have a very high safety profile.
