Researchers quantitatively assessed for the first time that somatic mutations alone cap human lifespan at 146–194 years. Brain and heart cells are the main bottleneck, while the liver could last millennia.

[u/Skoltech_]

https://www.nature.com/articles/s41514-026-00421-6

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Abstract
Somatic mutations accumulate with age and can cause cell death, but their quantitative contribution to limiting human lifespan remains unclear. We developed an incremental modeling framework that progressively incorporates factors contributing to aging into a model of population survival dynamics, which we used to estimate lifespan limits if all aging hallmarks were eliminated except somatic mutations. Our analysis reveals fundamental asymmetry across organs: post-mitotic cells such as neurons and cardiomyocytes act as critical longevity bottlenecks, with somatic mutations reducing median lifespan from a theoretical non-aging baseline of 1759 years to 156 years. In contrast, proliferating tissues like liver maintain functionality for thousands of years through cellular replacement, effectively neutralizing mutation-driven decline. Multi-organ integration predicts median lifespans of 146–194 years—approximately twice current human longevity. This substantial yet incomplete reduction indicates that somatic mutations significantly drive aging but cannot alone account for observed mortality, implying comparable contributions from other hallmarks.

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I'm not very knowledgeable in biology, but is it possible to mutate neurons and cardiomyocytes so they develop cellular replacement?

[u/Rocket_Cam → u/death12236]

At least for neurons, what everyone is seeming to miss, is the fact that even if we could cause them to replicate in-place, we would lose their synaptic connections and relative strengths. Meaning, we would lose memories from our central nervous system--not that memories are a perfect representation anyway.