Living to 1,000
“This means that all parts of the project should be fully working in mice within just 10 years and we might take only another 10 years to get them all working in humans. When we get these therapies, we will no longer all get frail and decrepit and dependent as we get older, and eventually succumb to the innumerable ghastly progressive diseases of old age. We will still die, of course – from crossing the road carelessly, being bitten by snakes, catching a new flu variant etcetera – but not in the drawn-out way in which most of us die at present. So, will this happen in time for some people alive today? Probably. Since these therapies repair accumulated damage, they are applicable to people in middle age or older who have a fair amount of that damage. I think the first person to live to 1,000 might be 60 already. It is very complicated, because ageing is. There are seven major types of molecular and cellular damage that eventually become bad for us – including cells being lost without replacement and mutations in our chromosomes. Each of these things is potentially fixable by technology that either already exists or is in active development. The length of life will be much more variable than now, when most people die at a narrow range of ages (65 to 90 or so), because people won’t be getting frailer as time passes. The average age will be in the region of a few thousand years. If you are a reasonably risk-aware teenager today in an affluent, non-violent neighbourhood, you have a risk of dying in the next year of well under one in 1,000, which means that if you stayed that way forever you would have a 50/50 chance of living to over 1,000. And remember, none of that time would be lived in frailty and debility and dependence – you would be youthful, both physically and mentally, right up to the day you mis-time the speed of that oncoming lorry.”
Longevity Escape Velocity
“The key conclusion of the logic I’ve set out above is that there is a threshold rate of biomedical progress that will allow us to stave off aging indefinitely, and that that rate is implausible for mice but entirely plausible for humans. If we can make rejuvenation therapies work well enough to give us time to make then work better, that will give us enough additional time to make them work better still, which will … you get the idea. This will allow us to escape age-related decline indefinitely, however old we become in purely chronological terms. I think the term “longevity escape velocity” (LEV) sums that up pretty well.”
SENS (Strategies for Engineered Negligible Senescence)
“There are certain species of rockfish, whales, turtles, and other animals that are known to live for hundreds of years without showing any signs of aging—a phenomenon known to biogerontologists as “negligible senescence.” No one knows for sure how long these animals can live for, but we know that they can live for over two hundred years without showing any observed increase in mortality or any decrease in reproductive capacity due to age. Striking examples are a 109 year old female rockfish that was captured in the wild while swimming around with fertilized eggs, and a hundred-plus year old male whale that was harpooned while having sex.
Q: What is negligible senescence?
Guerin: Basically, this refers to an animal species that doesn’t show any significant signs of aging as it grows older. Unlike humans and most other mammals, there’s no decrease in reproduction after maturity. There’s also no notable increase in mortality rate with age, but that’s a little harder to prove. I’ve been talking with a statistician and he’s asking, how do you know? To do a study of this type would take a couple of hundred years to complete. But compared to us there’s no noted increase in mortality rate. I mean, if you are ninety years old, you’re much more likely to die next year then you are if you’re only twenty years old. But we don’t seem to see any increase in mortality with rockfish and several of these other animals over time.
Q: So we don’t know if these animals are simply aging more slowly or not at all? Since we have haven’t found any rockfish or whales that live for four hundred years, that might suggest that there is a certain limit on how long they can live.
Guerin: Well, we just do not know. We honestly do not know. It really is unfortunate that there is so little known in this field. Ecologists have never thought of this in the terms that gerontologists are now thinking of it in. But this other group of organisms, those that possess what Finch termed “negligible senescence,” they don’t seem to be showing the classical signs of aging that we’re used to. So, who is to say the longest they could live? As an example, in Finch’s book that was published in 1990, at that time the longest lived whale was—I believe it was a Blue Whale—something like 108 years old. That’s like, okay, well that’s not so startling. Humans live longer than that. We’re mammals. They’re mammals. We live longer. Then a study was done on bowhead whales, and they found that out of forty whales sampled, four of them were over a hundred years old, and one of them was over two hundred years old. And they didn’t die of old age either—they were harpooned.”
“In humans, telomerase levels decline later in life and are only found in some types of tissue, but in lobsters, telomerase is found in all types of tissue. That likely accounts for lobsters’ ability to grow throughout their lives. And because lobsters’ skeletons are on the outside and the molting process allows them to periodically shed their exoskeletons in favor of a new, larger one, their constant growth isn’t a problem. With a steady, evenly distributed supply of telomerase, lobsters don’t approach the Hayflick limit, which means that their cells stay pristine, young and dividing. Related animal species with vastly different life spans are also a point of interest. Conventional mice live only three years, but naked mole rats can live for 28. Other animals being studied include whales, bats, rockfish, zebrafish and clams, the oldest of which, a quahog clam, lived to be 220 years old. In many of these animals, the rate of telomere deterioration corresponds with their lifespan. The longer the telomeres last, the longer the animals live. Studying these creatures may tell us much about human aging and lead to treatments for aging-related diseases. If one day humans discover an important new treatment for cancer, it may be due to one of these creatures — or to the 200-pound lobster living peacefully in a tank at Boston University.”
“For the past 21 years, across the limitless expanse of the North Pacific, a lonely whale has been singing, calling for a response. There has been none, and there never will. Picked up first in 1989 by NOAA hydrophones, the call is clearly a whale, but different than all other known species. Different enough that no other whale has responded in all this time. Hypotheses vary, but the mental image is definitely haunting.”