Increased mammalian lifespan and a segmental and tissue-specific slowing of aging after genetic reduction of mTOR expression.
Level 5 - mechanism / opinion, no new human data
Preclinical animal model study.
PubMed 23994476 · doi:10.1016/j.celrep.2013.07.030
What was done
Researchers evaluated lifespan, metabolic parameters, and age-related tissue function in viable mechanistic target of rapamycin (mTOR) hypomorphic mice carrying two mTOR(Δ/Δ) alleles, which produce roughly 25% of wild-type mTOR expression.
What was found
The hypomorphic mice exhibited reduced mTORC1 and mTORC2 activity and an approximate 20% increase in median survival. The mice were smaller than wild-type controls but showed no alterations in normalized food intake, glucose homeostasis, or metabolic rate. Aging tissue biomarkers were reduced, and functional assessments revealed preserved function in many, but not all, organ systems.
Why it matters
This demonstrates that systemic genetic downregulation of mTOR expression extends mammalian lifespan and clarifies that the resulting protection against functional decline occurs in a tissue-specific, segmental manner.
Limits
The study was conducted entirely in an inbred mouse model. Sample sizes, sex-specific differences, and exact quantitative changes for specific tissue biomarkers were not reported in the abstract. Findings from lifelong genetic knockdown cannot be directly assumed to mirror pharmacological mTOR inhibition in adult humans.
Cited by
- supports Animals with higher mTOR activity have shorter lifespans than animals with less active mTOR.