“Some animals exhibit a remarkable lack of aging, prompting the question: can humans achieve the same? The pursuit of immortality hinges on how we define it. It remains a distant fantasy if we envision immortality as an eternal, indestructible existence akin to comic book heroes. However, if we redefine it as the preservation of vitality, resistance to diseases, and the absence of age-related mortality, then the answer changes to ‘yes.’
This distinction may seem semantic, but it’s crucial. The former is a realm of science fiction, while the latter aligns with biological realities selected by evolution in certain species—an idea known as ‘negligible senescence.’ In fact, some animals are already living out this concept.
The encouraging news is that with the development of appropriate technologies, humans may enjoy significantly extended, healthy lifespans. Achieving negligible senescence, where age-related decline in survival traits, disease rates, and mortality doesn’t occur, might not be beyond our reach thanks to medical science and technology advances.
Senescence and negligible senescence:
Senescence refers to the gradual deterioration associated with aging, evident in most species. More precisely, senescence entails a decline in survival traits like strength, mobility, and senses, accompanied by increased mortality rates and reduced reproductive capabilities as individuals age. Humans and most animals experience a sharp increase in mortality rates beyond reproductive maturity.
However, some species defy this norm, aging much slower and demonstrating remarkable longevity. A few even exhibit negligible senescence, retaining their survival traits, mortality rates, and reproductive capabilities as they age.
For example:
- Rougheye rockfish: 205 years
- Aldabra Giant Tortoise: 255 years
- Lobsters (presumed negligible senescence): 100+ years
- Naked mole rat: 28 years
- Sea anemones: 60–80 years
- Freshwater pearl mussel: 210–250 years
- Ocean Quahog clam: 507 years
- Greenland Shark: 400 years
- Lake sturgeon (presumed negligible senescence): 152 years
- Clams like Panopea generosa (presumed negligible senescence): 160 years
- Hydra (biological immortality): No lifespan limit
Can we achieve negligible senescence?
While lobsters benefit from negligible senescence naturally, the same cannot be said for humans. Evolution would take too long to select such traits in us. Instead, researchers are exploring direct methods to harness the longevity mechanisms observed in creatures like the naked mole rat. They’ve successfully transferred these mechanisms to mice, opening the door for potential applications in humans.
Scientists like Dr. Aubrey de Grey propose an engineering approach to aging through repair-based strategies known as SENS (Strategies for Engineered Negligible Senescence). The Hallmarks of Aging, introduced in 2013, have further guided researchers in understanding and targeting the processes underlying aging.
Should humans achieve negligible senescence through SENS or other approaches, it could spell the end of age-related diseases and ill health—a noble aspiration indeed.
Negligible senescence doesn’t imply invincibility:
It’s essential to note that species with negligible senescence, while resistant to aging, are still vulnerable to predation, accidents, starvation, environmental shifts, and diseases. Consequently, very old individuals of these species are rare, especially in the wild. Determining their exact maximum lifespans often requires sacrificing them to examine deep tissues and bone markings.
In the quest for negligible senescence in humans, we face the challenge of multicellular aging, which isn’t easily circumvented.
The inevitability of multicellular aging:
In 2017, the media sparked debate by misinterpreting a research paper that suggested humans couldn’t achieve negligible senescence. However, the study merely emphasized that aging damage is inevitable but didn’t rule out potential interventions by future medicine.
Similarly, a 2021 study on the ‘invariant rate of aging’ was misconstrued, with the press incorrectly asserting that aging is unstoppable. In truth, this research revealed that, eventually, environmental improvements alone won’t further extend human lifespans, necessitating medical interventions targeting aging processes.
In conclusion, there’s a distinction between Hollywood-style immortality and achievable negligible senescence, which is a plausible goal in the coming decades. Nature has shown us that negligible senescence is possible, and we now have a more comprehensive understanding of aging. Interest in combating aging has grown within academia and investment circles. With defined targets and evolving knowledge, the prospect of extending healthy lifespans seems more promising than ever.”
reference
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[8] Nelson, P., & Masel, J. (2017). Intercellular competition and the inevitability of multicellular aging. Proceedings of the National Academy of Sciences, 201618854.
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