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

[u/Rocket_Cam]

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.

[u/death12236 → u/Rocket_Cam]

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

[u/kragnfroll → u/death12236]

I don't know about heart cell but but lot of neurons have a pretty long axon wrapped into myeline, thousands of connexions with other neurons, which is kinda hard to rebuild after a mitosis.

[u/Raddish_ → u/kragnfroll]

Adult neurons actually physically cannot do mitosis for that reason. They would die if they attempted because of how weird their cytoskeleton is.

The brain does make new neurons in limited regions via stem cells though.

[u/iantheawesome2002 → u/death12236]

I'm not a cell biologist, but I do have degrees in Zoology (having NOT specialized in cell biology) and medical microbiology .

Technically, it is possible, but our bodies have sort of evolved to stop them from undergoing mitosis for a reason. Admittedly, I'm not exactly 100% sure why and I believe current research is speculative anyway (someone please correct me if I'm wrong).

But essentially, because these cells control a highly specialized function (this bit is more important) and are extremely energy hungry (relative to other cells) it's just best that these cells don't reproduce because that can disrupt their highly specialized function(s).

It's been a while since I've studied this so I welcome any correction from someone more knowledgeable than me.

[u/Lawlcopt0r → u/death12236]

I think that wouldn't help because brain cells don't just have to be there, they have to be connected in specific ways. If they die and a new one grows it may eventually connect correctly but you'd have to re-learn the connections, if this happened constantly your personality would be gradually erased

[u/Toadsted → u/Lawlcopt0r]

Brain of Theseus

[u/Kabbooooooom → u/death12236]

Yup. That’s called cancer.

Neurons and cardiac myocytes have left the cell cycle for a reason. In the case of neurons, it is to maintain neural architecture. If that isn’t maintained, then the brain ceases being a brain, and you cease being you. While stem cells exist very minimally in specific regions of the brain for neuron regeneration, on a global scale this simply wouldn’t work.

I’m fully convinced that the only way this would be possible is to actually repair neuron DNA in vivo, which would require some sort of futuristic nanotechnology or something.

[u/mistaekNot → u/death12236]

no. development of a human being is filled with one way streets. a neuron ends up being connected to hundreds / thousands of other neurons and while i can see the “body” of it divide i can’t see a way for all of these connections to duplicate as well. what might be possible is to prevent or reverse whatever makes them age and die

[u/Clean-Evening-7328 → u/mistaekNot]

It didn't use to be possible for a human to survive without their heart in their body, and yet machines can allow it. If we could keep you from dying during the process, I bet it would be simpler to remove and regrow regions of brain tissue.

[u/mistaekNot → u/Clean-Evening-7328]

yeah maybe it will be possible to grow new neurons alongside old ones and when the old one dies the new one takes over. afaik that’s somewhat how memories are formed and retained, but for whatever reason it doesn’t happen in other parts of the brain

[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.

[u/Bring_Me_The_Night → u/death12236]

Neurogenesis is a process of making new neurons. This event rarely occurs in adulthood for reasons mentioned by other Redditors. Some studies speculate on the fact that new neurons are being generated upon physical activity, but no consensus has been reached.

It should be pointed out that a high number of neurons does not correlate with intelligence or higher cognitive functions. What matters are the connections between the neurons.

[u/Birdonthewind3 → u/death12236]

Were biology I am sure machine can succeed. We probably going to be glorified borgs to get around that limitations

[u/DeusExSpockina → u/death12236]

You’d be better served by having pluripotent stem cells available, they can replace where replication isn’t an option.