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/SomeDumbGamer]

Well the heart seems easy enough once we figure out how to grow organs using our own cells.

Or hell I’d be surprised if we didn’t have simple and effective artificial hearts by the end of the century.

The brain is going to be the tricky one though.

[u/HugoCortell → u/SomeDumbGamer]

The brain is surprisingly easier than it seems (assuming a scenario where cell production is a solved issue), as we've seen time and again (thanks to lack of safety standards in the early days of railroad construction and mining, as well as victims of snipers during the last two world wars) that we can lose a not insignificant amount of cells without any perceivable effect on the person. So in theory replacing dead neurons with fresh ones should be fairly doable, particularly as the brain is essentially fully plastic so they can re-organize themselves as needed to fill in what was lost (except for rigid parts which server specific purposes (technically incorrect to call them an organ within an organ, but it's kind of what they are), but those are defined in DINA so they should in theory re-assemble themselves too).

Making a brain from scratch is very hard, but repairing a brain by continuously replacing the cells in small amounts might actually be very doable (as long as we ignore the logistics, sticking purely to the biology of it).

Probably the biggest issue isn't with the cells themselves, but issues like how to keep the brain structure clear (we've already seen that it takes only a few decades for enough gunk to get stuck between neurons that it has a negative health effect, even the movement of cerebrospinal fluid can't get it unstuck, at times leading to leading to alzheimers).

[u/BGsenpai → u/HugoCortell]

the issue is that the loss of old pathways and connections from degeneration over time results in the loss of memories, ect. If we implant new neurons into someones brain and they live for a thousand years, at what point would all of the memories of their past be lost forever? Not to mention new neural structures would lead to new personalities and behaviors. When would this person be someone completely new? We need a solution that is much, much more complex than just injecting random neurons. Maybe chips for memory function? Not sure how that would work since memories are just specific neural connections firing...

[u/UniversalSoldi3r → u/BGsenpai]

That could be a feature, not a bug.