From what I've heard/read telomere length as the anti-aging curing may be a bit overrated, because we actually want to prevent cognitive degeneration (who cares if you live longer if you can't think as well). There's a very interesting ongoing study called the Lothian Birth Cohort Study, where they tested cognitive functioning in 11 year olds born in Edinburgh in the years 1921 and 1936. In the late 1990s/early 2000s the individuals were tracked down (now in their 70-80s) and researchers did extensive, extensive testing to try to explain variances in cognitive functioning between their scores at age 11 and now (why did some people lose ability/others gain?)
I talked to the director of this massive study and he said there was no correlation with cognitive functioning and telomere length [1] and the entire thing may be a bit overrated. Interestingly enough though, he said there there was a strong correlation with DNA methylation[2] with increased methylation associated with worse cognitive aging.
Very interestingly, DNA methylation decreased for Scott after his time in space...
Regarding longevity, it's also worth noting that telomere shortening are a very effective anti cancer mechanism.
Cancer is the runway division of cells. Preventing cell division when the telomeres are too short ensures there is a finite number of times a cell can divide, meaning there is a finite number of times a cancer cell can divide. This helps prevent cancer from dividing indefinitely. Especially in older folks, we see how terrible cancer can be when those cells mutate and can regenerate telomere length, giving themselves unlimited division.
It's the physical trade-off we have with lengthening or preserving telomere length. They give all of our cells more divisions, good and bad. Since cancer is an exercise in the law of large numbers (how many random mutations will it take for it to hit a critical point in your DNA?), Longer lifespans with longer telomeres will inevitable also mean more aggressive cancers.
So if my intuition is applicable (which it's probably not)- it's longer because it stretches out, not because it's accumulating material? I assume that's not really possible though...
Sure. But the question assumed that the physical length can be variable depending on the environment. Even if that was the case, measurement of telomeres by the sequence themselves will be independent of environmental factor.
Maybe this is not the perfect analogy, but the character 'a' and the character 'A' might have different heights, but they still represent the same letter of the alphabet.
Off the top of my head: I wonder if astronauts are on lower calorie diets than usual.
Lowering calorie intake is one of the few well known ways that lifespan can be increased. Will have to see if there's any research correlating low calorie diets and telomere length.
There is also one sure-fire way to increase telomere length : get cancer.
So these people were in a thin metal cube, exposed to abnormal levels of ionizing radiation, ... and after that there was telomere lengthening ? I always heard that astronauts, given the groups they're selected from, have suspiciously short lifespans. Still somewhat above average, but these guys got selected from the creme de la creme. Half of them should live to 120, and that is definitely not happening. I've never seen a good study actually comparing it though.
According to several doctor friends of mine, balance is the best way to go for a long life. Being too thin will kill you, because once you're 65 or 70 or so you will lose the ability to quickly gain weight. A significant number of people dying from "natural causes" die as follows : they get infected with something stupid, like a flu virus. Or they break a hip or something. Either way, they get really under the weather. Result: they lose weight, a lot of weight, rapidly. If your weight falls under about 35 kg, odds of survival drop dramatically, and they die from "complications" (in practice: secondary infections resulting in metabolic exhaustion: your body simply cannot maintain the minimum energy level to keep you alive. On the plus side: very peaceful way to go, and likely quite comfortable too). Keep in mind it will take a year to work your way back from 40kg to 50kg at such an age, so the higher you go the more likely you'll drop back down due to another incident before recovering.
And of course, exercise only helps up to a normal level. If you spend 2 hours every day running, that is definitely in the "shortens lifespan" area. 10 minutes, probably very good for you. And of course, the obvious : exercise increases the odds of accidents happening. Accidents, even stupid ones, can kill.
> There is also one sure-fire way to increase telomere length : get cancer.
This badly needs a source.
This article from 2013 [1] says the opposite, that shorter telomeres are associated with cancer:
In recent years, shorter telomeres have become associated with a broad range of aging-related diseases, including many forms of cancer, stroke, vascular dementia, cardiovascular disease, obesity, osteoporosis and diabetes.
And another [2]:
"Telomere shortening is common in cancer, but the degree of shortening varies from one cancer cell to another within each patient, and this variability may give us a better idea of how prostate cancers behave."
Edit:
At the top since I think it may qualify my comments: I think there's a causation/correlation incongruity in this, the parent, and the grandparent posts. Telomere lengthening can lead to cancer; getting cancer is not necessarily a "sure-fire way to increase telomere length"
"Cancer" is an unbelievably broad term. Generally speaking, expression of telomerase and maintenance of telomeres is seen in (many) cancers. The background behind this is that as telomeres shorten with each cell replication, they get to a point where they are too short, and the cell stops dividing. Cancer occurs when cells that are not supposed to divide keep dividing.
>"According to several doctor friends of mine, balance is the best way to go for a long life."
From what I understand, this is just the "moderation is good, extremes are bad" meme. Similar things are recommended regarding diet composition etc. I usually read it as "we don't really know, so just do what everyone does".
>"And of course, exercise only helps up to a normal level."
What's normal? You think people only spent 10 minutes a day running, in the past?
1 hour is 10 km at a leisurely pace. If I go for a run in the morning, and in the evening, I'm very confident that I'll have better chances to live longer than someone who runs less than 2 km a day. Running ultramarathons will shorten your life, maybe. But not a jog or two.
---editing to add details after googling around a bit---
Intensity of physical exercise is measured in metabolic equivalents (MET)[1]. There is also a table with MET values for common activities.
I looked at some studies, but most are not interesting. One[2] defines "vigorous PA" like this:
Assessments of vigorous physical activity were based on a single set of intensity categories applied at all three time points; these were: 1) walking, 2) alternately walking and jogging, 3) jogging (light running), and 4) running. Vigorous activity was defined as levels 2, 3, or 4 (all more intensive than normal walking), performed at least 3–5 times/month in 1975 and 1981, or at least for 30 min each week in 1990.
(so - not useful)
However, I found another one[3], which has this to say:
Several of us have recently analyzed 55,000 individuals (13,000 runners) from the ACLS database during nearly 15-year follow-up to assess the impact of running on CVD and allcause mortality.11 Compared with nonrunners, runners had a reduction in all-cause and CVD mortality of 30% and 45%, respectively, with an average increase in survival of 3.0 and 4.1 years for all-cause and CVD-related survival, respectively, after adjusting for lifestyle factors (eg, smoking and obesity) and medical conditions (eg, HTN and T2DM). Persistent runners appeared to receive the full benefit from mortality reduction, whereas those who started running but stopped or those who were not running at baseline but subsequently started running appeared to receive nearly half of the benefit received from CVD and all-cause mortality reduction. These results are impressive, though perhaps not surprising when considered in the context of the data outlined in previous sections, showing myriad health benefits of running.
However, when assessing doses of running, somewhat surprising results were found. Runners generally had considerably higher levels of CRF than did nonrunners, and moreover, CRF levels in runners progressively increased with increasing doses of running (Figure 2).11 Most evidence indicates better survival with estimated MET levels greater than 10,23-25 although some evidence indicates progressively better survival with even higher CRF levels.45 When 13,000 runners were divided into quintiles of running doses (miles per week, times per week, minutes per week, and speed), no significant differences in the benefits were noted for any of the running groups.Infact,runnersinquintile1(eg,<6 miles/wk, 1-2 times/wk, <51 min/wk, <6 mph) received the full benefits from running with regard to reduction in CVD and all-cause mortality (Figure 3).11 These results suggest that maximal benefits of running occur at quite modest jogging doses and that runners in quintile 1 have almost similar benefits of running compared with those in quintile 2 to quintile 4 and have a slight, nonstatistically significant trend toward greater benefitcomparedwith those in quintile 5. However, in contrast to the results of the Copenhagen City Heart Study,14 our results, from a larger sample with much better statistical power, indicated that runners with high doses of running in quintile 5 still had significantly better CVD and all-cause survival compared with nonrunners.11 However, these higher doses of running were not necessary to achieve maximal reduction in CVD and allcause mortality.11-14
Aren't both of those activities more endemic in generally healthy people anyway (tend to live longer)? It'd be a bit of a stretch to say that it'll improve the genetic variables effecting your lifespan.
I'd characterize the research so far as suggestive, but not conclusive. It's fairly well supported that caloric restriction extends the lives of many rodent species. There have been two primate studies, both finding health benefits but only one finding longevity. No human trials have produced results yet to my knowledge.
In Elysium, living in space wasn't directly connected to a longer lifespan. It just so happened that the elite segment of the population was able to afford both.
The NASA article [1] gives a little more background, and offers another explanation:
Bailey found Scott’s telomeres on the ends of chromosomes in his
white blood cells increased in length while in space.
This could be linked to increased exercise and reduced caloric
intake during the mission.
I have no idea what the significance of telomere is (googled it but really want a TL;DR version). Can someone explain this preliminary result in layman's terms?
Telomeres protect your DNA from degeneration during cell division. As you age, your telomeres get shorter and shorter, and ultimately lead to cell division not producing viable cells anymore.
Quoting wikipedia:
> During chromosome replication, the enzymes that duplicate DNA cannot continue their duplication all the way to the end of a chromosome, so in each duplication the end of the chromosome is shortened [...] The telomeres are disposable buffers at the ends of chromosomes which are truncated during cell division; their presence protects the genes before them on the chromosome from being truncated instead.
> Telomere shortening is associated with aging, mortality and aging-related diseases. In 2003, Richard Cawthon discovered that those with longer telomeres lead longer lives than those with short telomeres. However, it is not known whether short telomeres are just a sign of cellular age or actually contribute to the aging process.
The human body has a mechanism to reset telomere length during reproduction; i.e., babies are born with "full length" telomeres.
Can anyone shed light on why this mechanism is so hard to trigger in an adult? What are the technical difficulties in artifically lengthening telomeres?
I'm no biologist, but from what I understand the body actually does maintain telomeres over time, it just doesn't keep up with the loss from cell division over a lifetime.
Purely speculating, death to "old age" is rare in nature so the process merely has to be "good enough" for our genes to compete rather than perfect enough for immortality.
To be slightly more precise and because this is a very well established mechanism that gets overridden in quite a few circumstances : this is a "death clock" built into your DNA. One of several, but rather obvious and thus well known. A number of cell functions in your body are exempt from this death clock, most obviously the reproductive cells.
It causes your body to (very) slowly lose the ability to grow new cells. Also cells with shorter telomeres "senescence", which is sort of like aging : they become slower, and more brittle.
Amongst the advantages this has is that it protects against cells that increase their metabolism too high and against cells that rapidly divide (by having them senescence and die). The obvious disadvantage: it eventually kills you.
It seems likely, given that this mechanism is "deliberate" and definitely under the control of your DNA, that you live longer and more successfully with aging than without.
> It seems likely, given that this mechanism is "deliberate" and definitely under the control of your DNA, that you live longer and more successfully with aging than without.
Not necessarily "you" but perhaps the species as a whole. Without the aging and inevitable death our ancestors may have evolved slower.
When a cell divides, the very ends of the DNA cannot be copied. Rather than lose genetic material on every division, there is a cap of DNA at the end whose sole purpose is to be lost without ill harm when cell division occurs--this cap is the telomere.
Clearly, as you age, telomeres would shrink to nothingness. However, there is a mechanism to add more DNA to telomeres... which seems to be off for most cells. So it's thought that shortening telomeres is a cause of cellular aging, and lengthening them is thought to be able to halt or reverse cellular aging and hence aging in general.
The actual biology experiments generally seem to suggest more "we don't really know what's going on here."
In short, what's being said is "going to space seems to show an improvement in a metric that we really, really hope is correlated with increased longevity."
If telomere length reduction correlates with aging, then the flight twin (Scott) aged less rapidly. Not everyone agrees that telomere length is a reliable aging indicator.
Another really interesting result was in DNA methylation, a gene activity regulation process [1].
Scott's DNA methylation decreased during flight while his Earthbound twin's methylation increased during that time. After Scott's return to Earth, DNA methylation in both twins returned to baseline level. The last result puzzles me.
Shorter telomeres are correlated with aging, stress, and a higher incidence of cancer. We're no entirely sure whether short telomeres can increase the chance of cancer or whether other things that can cause cancer tend to decrease telomere length or what but whichever way it goes short telomeres are a good sign in terms of health.
Time dilation is never the fountain of youth. You don't experience any more time. Yes, you live to a later calendar year, but if that's at the price of having fewer seconds per calendar year in which to live, what's the point?
Interesting results. But were twins needed for this discovery? I would imagine the the telomere length change could have been discovered by pre-mission, in-mission, and post-mission sampling. I'm guessing this was discovered in this study because of the in-depth DNA sampling, not due to having a twin to compare to.
The twins were used because they are doing a wide variety of genomic testing. One serves as a baseline. So twins will give a low variance between candidates.
My understanding (https://www.ucsf.edu/news/2013/09/108886/lifestyle-changes-m...) is that telomeres can lengthen due to diet, exercise, etc., so having a twin on earth with a similar diet and exercise regimen would be worthwhile to account for as many variables as possible.
I'm not sure of the exact details in this case, but having a twin as a baseline will likely to useful in a number of ways. Things change over time - how much did Scott's telomere length change in comparison to before he went to space and in comparison to his brother?
I recall this being an element in Heinlein's "The Moon is a Harsh Mistress". The lunar colonists live much longer than their 'Earthworm' counterparts because of the low gravity.
As the original submitter: it seems like this post, although a duplicate, was generating further engaging and informative discussion beyond that discussed in the previous post, arguably more than the previous post (on the basis of number of comments within the first hour being equivalent to number of comments over the course of the 24 hour lifetime of the previous post). Not sure if this was you, but marking as duplicate has effectively killed that discussion by making the post disappear.
As the HN policy around reposts is somewhat subjective "If a story has had significant attention in the last year or so, we kill reposts as duplicates. If not, a small number of reposts is ok," I'd contend that marking as dupe in this case wasn't the right move. While the post from yesterday did get significant attention, that post moved past the front page, and today's repost resulted in meaningful and engaging further discussion. Unfortunately now that discussion is most probably dead, as is the discussion on yesterday's post, where new comment activity has stalled.
Furthermore, my intent with this submission was to highlight a specific finding of the research that is not the emphasis of the previous post (namely, the unexpected result involving telomere length). The discussion on this post generally focused on that result, whereas the discussion on the previous post did not.
I think this could be solved by having the [dupe] tag link back to the original. I've seen a few posts marked as dupe and it's sometimes difficult to trace down the original.
I talked to the director of this massive study and he said there was no correlation with cognitive functioning and telomere length [1] and the entire thing may be a bit overrated. Interestingly enough though, he said there there was a strong correlation with DNA methylation[2] with increased methylation associated with worse cognitive aging.
Very interestingly, DNA methylation decreased for Scott after his time in space...
[1] https://www.ncbi.nlm.nih.gov/pubmed/21194798 [2] https://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin/study.cgi?...