2 replies to this topic

[reason]

In this day and age, the big advantage provided by conducting studies of aging in short-lived, small species such as nematodes is that it is cost-effective to build increasingly sophisticated processes of automation for such research. Gathering very detailed data on large numbers of individuals becomes possible, and this allows for greater introspection into the mechanisms of aging through statistical methods. The results here are quite interesting, for example, and could not be obtained from mammals given current budgets and constraints on technology:

In order to study life span dynamics at the population level, researchers constructed the Lifespan Machine, a device comprising 50 off-the-shelf flatbed scanners purchased from an office supplies store. Each scanner has been retooled to record 16 petri dishes every hour, totaling 800 dishes and 30,000 nematode worms. The scanners capture images at 3,200 dots per inch, which is a resolution high enough to detect movements of eight micrometers, or about 12 percent of the width of an average worm. The researchers subjected the worms to interventions as diverse as temperature changes, oxidative stress, changes in diet and genetic manipulations that altered, for example, insulin growth factor signaling. The Lifespan Machine recorded how long it took the worms to die under each condition. The researchers then aggregated the data, generated life span distribution curves for each intervention and compared results.

The life span distributions provided considerably more information than just changes in average life span. The research team measured variations arising in ostensibly identical individuals, looking at how many worms died young versus how many made it to old age under each condition. This comprehensive view was important for capturing the dynamics and randomness in the aging process. In one sense, the findings were not surprising: different circumstances produced different life spans. Turning up the heat caused the worms to die quickly, and turning it up higher only increased that rate. Pictured as bell-shaped distributions, certain interventions produced a thinner, high-peaked bell, while others resulted in a more drawn-out and protracted bell.

Despite these obvious differences, the researchers found an unexpected uniformity among the curves. The various interventions seemed to affect the duration of life in the same way across all individuals in the same population, regardless of whether chance or randomness had a short or long life in store for them. No matter which genetic process or environmental factor the researchers targeted, all molecular causes of death seemed to be affected at once and to the same extent. These findings suggest that aging does not have a single discrete molecular cause but is rather a systemic process involving many components within a complex biological network. Perturb any node in the system, and you affect the whole thing.

Link: http://hms.harvard.e...bes-cause-aging

View the full article at FightAging

[resveratrol_guy]

I would say that this experiment provides false proof of what might be termed the "survival curve paradox", which is that greater expected lifespan implies greater time in senescence. In other words, it is actually impossible to create a lifelong intervention which "squares the curve" without reducing expected lifespan. Practically speaking, this means that fasting, pterostilbene, oxaloacetate, and the myriad of other life extension techniques, while they may succeed in helping us live longer, will also extend our suffering.

 

But the deception here is by way of study design. The investigators appear to have made various interventions -- temperature, diet, genetic changes, and so forth -- which remained contant throughout the lives of all the worms in any given petri dish. What they did not do is temporally hybridize these interventions by, say, providing minimal food and low temperature until late in life, followed by excessive calories and high temperature.

 

What I'm getting at, taken to its extreme, is that the only way to resolve the survival curve paradox is to commit suicide. Of course, a survey of global statistics makes it obvious that this route is generally unacceptable to most of humanity. Additionally, doing so may prevent one from obtaining cryonic suspension due to contractual stipulations. But perhaps there's a more acceptable alternative, namely, leading an increasingly happy-go-lucky life with increasing age.

 

When I was 21, a catastrophic error in judgment landed me on my back on a grassy slope, facing up to the sky, with my bicycle smashed into a cement drain a few meters below me. I could neither breathe nor see for many seconds. Despite what you might think, the experience was in no way depressing or terrifying, although in those seconds which seemed like eons, I assumed that I was on the precipice of death. To my astonishment, I walked away minutes later, with only a cut on my face and a headache to testify to the event. Looking back through the fortunate eyes of a surviver, I can nonetheless confirm that it would have been a far superior way to go than via any of the chronic diseases that plague us on a daily basis.

 

So if you want to live longer and "square the curve", then I suggest taking up skydiving, underwater cinamatography, spelunking, and mountaineering late in life. Then you can share your experiences with the rest of us, enhance your social relevance, and most importantly, increase your chances of avoiding senescence. Just the same, I appreciate those of us who tolerate senescence in order to wring the very last seconds out of the hourglass of life, in order to maximize the benefits of one's honed talents on society.

[corb]

I would say that this experiment provides false proof of what might be termed the "survival curve paradox", which is that greater expected lifespan implies greater time in senescence

 

I wouldn't write it off as false so easily.
What they did was continuously treat the worms with aging slowing interventions.

In this case it only makes sense that the curve will elongate with the lifespan and naturally will lengthen the time required for a crash.

 

It just goes to show aging slowing interventions are just generally undesirable.

Maybe they are the only easily available "treatments" for aging now - sure, easy to research as well - ok, still ultimately undesirable and as reason likes to point out - a waste of time and money.