Can Aging Be Cured?

Thermodynamics doesn't say that "everything is bound to break down, and that we won't be able to predict all of the ways it can happen".

I guess you're referring to the second law of thermodynamics. It says that the entropy of the universe tends to increase. This is predictable and the lack of "negentropy" won't be an issue for a long time. The heat death of the universe is supposed to be on the order 10^100 years from now, so is not very relevant when talking about curing aging.

We're now learning how to "reset" the immune system.

1. Collect immune system "seed' cells.

2. Wipe out the existing immune system with chemo therapy drugs and other violence.

3. Inject the collected cells and let them build a new fresh immune system.

You now have lost all your immunities and will need to be revaccinated for everything. But any autoimmune disease like MS you had is probably also gone.

http://www.nih.gov/researchmatters/january2015/01122015reset...

> I suspect that "curing" aging will consist of extending the average lifespan a decade at a time, as we cure dozens of different conditions. Something as complex as a human body is always going to have some unforeseeable epiphenomenal mode of failure, given enough time.

There's a very foreseeable failure mode that this approach doesn't address at all.

Who'd win in a fight: a 150-pound 25-year-old guy or a 170-pound 75-year-old guy?

If you think the answer is "the 25-year-old", you've noticed a problem with aging that slowly extending lifespans doesn't solve. It's not just about whether you're alive or dead.

In other words, investing in future will actually make sense.

Considering how little progress we've made, I hardly think that our lifespans are the primary limiters in that venture. I mean you can travel to Mars in 8 months-3 years, yet we haven't.

Energy is our primary limitation right now. We have nuclear but are too afraid of launching large quantities of the raw materials into atmosphere in case of a catastrophic failure (and showering land OR sea with some heavy radioactive metal).

We also have fossil fuels which are very energy dense, but still heavy/expensive. And finally we have solar which has been a long-term popular form of spacecraft energy, but it doesn't provide enough to travel between planets YET.

Ultimately if we invented "infinite safe energy" tomorrow I don't see Mars or greater space exploration as being too big of a challenge. In particular as getting stuff into atmosphere is now energy-free, and your only limit is the cost of the raw materials.

I doubt that life-span would make much of a difference, and I would even suspect that overall, development would slow down with a longer life span even without aging of body and brain, as the 'caste of the old and powerful' will defend their old ways and suppress new radical ideas coming from the young, which will be in an even bigger minority then today. Just imagine what the world would look like if Stalin would still be alive, or if the government of East Germany wouldn't have entirely consisted of senile old fogeys, the iron curtain would very likely still be up.

Or not taking the cure.

You left out murder and war.

I doubt it will be awkward. It will be viewed that aging is a disease, that we have the cure now, so there's one less way to die. Getting rid of polio didn't make the other ways of dieing more awkward.

There is also a slow dissolution into a different state of being.

I imagine humans living long enough to begin augmenting their bodies and brains into a thing that no longer resembles the original being. Or even a form of life as we understand it today.

Or starvation.

Most lives already end with a disease. You don't die from old age.

Investing in things other than not-freaking-dying - now that's awkward.

Would have profound impact on how we value our own lives (and others). If you are 60 you might get a motorcycle because what the hell. Worse case you crash and lose 20-30 years of which only 10-15 are good. With aging out out the window you could have centuries to lose.

Telomeres are repeating sequences of nucleic acids that cap the ends of chromosomes in the cell nucleus and stop actual gene-coding DNA from being chopped off when a cell divides. The mechanisms of DNA replication require extra leg room at the ends of the strand, a trailing sequence that is not copied over to the new strand under assembly - and the primary role of telomeres is to be the part that is dropped on the floor. A little of their length is thus lost with every cell division. This shortening acts as a clock to count cell divisions, and cells with very short telomeres stop replicating - they either enter cellular senescence (which ideally then causes the immune system to destroy them) or destroy themselves directly via programmed cell death mechanisms.

Telomere length is more dynamic than this simple picture, however. In some cell populations, such as the various types of stem cell that maintain tissues and produce new cells to replace those lost or damaged, an enzyme called telomerase continually lengthens telomeres so as to allow a cell lineage to continue dividing indefinitely.

Ordinary, non-stem cell populations exhibit a range of telomere lengths, some short, some long. You might imagine that a population of cells replenished more frequently or recently by stem cells will have longer telomeres on average. A population that is receiving less support might have shorter telomeres. Researchers have shown that a higher proportion of short telomeres in white blood cells correlates well with ill health or stress, and somewhat correlates with age. Some more complex measures of telomere length, a step above just taking the average, have been shown to correlate well with age, however, and other techniques do a fair job of predicting future life expectancy in laboratory animals.

A few years back a brace of startup biotech companies were aiming to address aspects of aging by lengthening telomeres through the use of telomerase. None of that went anywhere, unfortunately, but it's possible that they were just too early - it is frequently the case that all of the first batch of companies in a new area of biotechnology fail. It's a tough business to be in. I was a skeptic at the time regarding their potential for success based on my expectation that telomere length will prove not to be a root cause of aging. It looks a lot more like a marker for (a consequence of) some of the responses to the root causes of aging, in particular the reduction in stem cell activity that is characteristic of old age.

Nonetheless, researchers are demonstrating extension of life in mice through telomerase these days, but it is as yet unknown as to exactly why this works. Perhaps it makes stem cells work harder to maintain tissues, perhaps there is just one critically limiting type of stem cell or tissue that benefits from more telomerase, or perhaps it involves other effects causes by increased levels of telomerase that have nothing to do with telomere length. It is worth bearing in mind that there are considerable differences in natural levels of telomerase and the resulting telomere dynamics between mice and people, however. Telomerase therapy is probably not something you'd want to just up and try without the research community first obtaining a much greater understanding of why it works to extend life in mice.

Why? Well, the risk of telomere lengthening in humans is cancer. Any mechanism that globally, or possibly even narrowly, extends telomere length in people will raise the risk of suffering cancer. The whole system of telomere dynamics and cellular senescence is intimately tied to the processes of cancer suppression, while all cancers evolve ways of lengthening their telomeres to allow unlimited cell division. Boosting your telomerase levels looks a lot more risky to me than, say, undergoing first generation stem cell transplants.

There continues to be a lot of activity in telomere research and development. The present brace of telomere-related biotech startups are commercializing ways to measure telomere length rather than extend it. The products are tests that will at first add another measure to inform patients on the state of their health, then possibly act as an effective biomarker of biological age, and perhaps later prove useful in further research if it turns out that telomerase-based therapies can be beneficial in humans.

Unfortunately, this "problem" was already solved a long time ago... by cancer cells ! [1]

It turns out that having immortal cells (by either avoiding death signals or by having "enhanced" replicative machinery is a great way to develop cancerous cells. So you have to carefully regulate the lifetime of the cell... which is what telomere are doing in the first place.

[1] Many many sources, but for instance the "Enabling Replicative Immortality" of Hanahan&Weinberg 2011, "The Hallmarks of Cancer: the next generation" http://www.sciencedirect.com/science/article/pii/S0092867411...

Do you have a deeper point—which I'm missing—or is this FUD?

Its a cause of death. We like to avoid those. And we know multicellular organisms exist that can maintain their telomeres and avoid senescence.

We are almost certainly going to be able to genetically engineer that into future people at some point, among a lot of other useful things. Dunno if we are going to manage to get gene therapy that can alter living humans so drastically before they die, though. And who knows when it will happen, just that it almost certainly will, unless we blow ourselves up.

Sometimes I feel we should cure living. I would prefer to live only 70 years but fully, having built good human relationships, knowing how to learn, rather than 100 unfulfilled ones.

You might be mistaking cause for a reason here.