Can we prolong our lifespan and even achieve immortality?

[ChrisVer]

Probably this has been asked before...but...
If we know what are the causes of our death by age, why can't we overcome them, prolong our lifespan and even achieve immortality?

 

[Guco]

Death from old age does not have a single cause. It is simply a by-product of the fact that from an evolutionary point of view, there is no significant advantage to invest in indefinite lifespan.
Any evolutionary change that adds to longevity always requires investment and past a certain point any additional lifespan will be less beneficial than other meaningful ways to use that energy, such as increased fertility or reduced mortality from cancer. This means that there are many processes in our body that simply did not evolve to be indefinite (and some may even have evolved to be definite) and will at some point break down. To 'fix' all those processes would require biotechnology that we simply do not have at this point. So I think you overestimate the current state of technology. But I see no reason why we couldn't attain biological immortality at some point in the future.

 

[Pythagorean]

The cause of natural death (non-injury, non-violent, non-congenital) is ultimately the result of a very complicated system breaking down. There are multiple sources of failure. Knowing the causes isn't enough though, we'd have to know the exact mechanisms of the causes and we'd have to know a method to control the system in a protective way. This would require molecular-level manipulations in a live subject that we aren't capable of. One example: cancer metastasizes - that is to say it spreads through the body. We have no way of detecting and isolating all those cancer cells without harming the patient - lots of people are working on the problem, but you have to realize that cancer is an umbrella term for many different kinds of failure in programmed cell death. Depending on what kind of cancer and what kind of tissue it is, different molecular pathways are failing and would require different techniques to detect and treat. People are working on the problem and have made some advancements, but nothing has led to a "cure for cancer", yet.

 

[jim mcnamara]

Take another point of view: natural selection works on the principle of differential survival of offspring, based on genetic traits. No death == we would all still be Archaea, like cyanobacteria (kinda like refrigerator parasites) -- that first emerged 3+ billion years ago. No death -> no change.

The no death scenario is impossible, really:

Because the environment has limits. Those limits restrict resources, some beasties are better at getting resources so the less successful beasties die out. Rinse, repeat several hundred trillion times every billion years, and voila - you get Lady Gaga, Math and Physics, and other assorted oddities, including of course, humans, mammals, and every other wee beastie. Evolution is analogous to Conway's Life. Or Langston's Ant. Take a set of very simple rules. Iterate ad nauseum and you end up with complexity where there seemed to be none. Emergence.

 

[quantumfunction]

Good question and I was thinking about things along a similar line.

Why can't we repair our bodies after death? Say someone dies of a heart attack, why can't we just repair the damage or give them a new heart like we repair a car or a TV set. When a person dies, what has died biologically that prevents someone from repairing the damage and resuscitating the person that died? I remember reading something about blocking the death signal for stroke patients, could it be that simple?

 

[GTOM]

Good question and I was thinking about things along a similar line.

Why can't we repair our bodies after death? Say someone dies of a heart attack, why can't we just repair the damage or give them a new heart like we repair a car or a TV set. When a person dies, what has died biologically that prevents someone from repairing the damage and resuscitating the person that died? I remember reading something about blocking the death signal for stroke patients, could it be that simple?

What has died biologically, like the brain?

 

[Ryan_m_b]

Good question and I was thinking about things along a similar line.

Why can't we repair our bodies after death? Say someone dies of a heart attack, why can't we just repair the damage or give them a new heart like we repair a car or a TV set. When a person dies, what has died biologically that prevents someone from repairing the damage and resuscitating the person that died? I remember reading something about blocking the death signal for stroke patients, could it be that simple?

We can't just replace body parts because we don't know how yet. Getting a group of cells to replicate, form the right tissue types, form the right 3d structures and do so in a manner that is totally healthy is beyond us right now. The field of regenerative medicine is looking into creating new organs and tissues but it's still in its infancy (if you're interested though I suggest looking it up). Even if we could replace any organ on demand we probably still wouldn't solve aging though like any medicine it would increase life expectancy. There are a host of other processes that may be difficult to understand, let alone overcome. Like DNA damage, epigenetic factors, damage to non-replacable parts (i.e. the brain).

 

[ChrisVer]

I don't know because I am a physicist (probably) and not a biologist or anything similar to medicine. However it seems really weird to me, that we are able to manipulate the elementary particles, and on the other hand, yet we are unable to manipulate larger structures like molecules or groups of molecules in any way that would lead to a living person...
Of course the stochastism grows at this level (like the cancer cells that were mentioned - which we are unable to track down and destroy them individually without causing harm to the patient). We have been able to produce populations of cells that can regenerate artificially (that's what medicine/pharmacy science is all about) but it's still a weird we haven't been able to take this into a larger step. I wonder whether the philosophy of bioethics is to blame here, or our lack of technology ... or my amateur approach on the topic.

 

[Ryan_m_b]

No offence intended here but it is your amateur approach/level of understanding. It's one thing to manipulate one elementary particle, it's quite another to manipulate an emergent construct of billions of atoms. The complexity of a single cell is vast and we still are a long way from fully understanding how everything works (we've not even properly characterised every biomolecule within humans). On top of that understanding and repairing are two very different things. We've got a very good understanding of how cancer forms but that hasn't made dealing with it easy, on the contrary we've found scores of ways that we can't treat the disease. And for the record we can't take cells and regenerate them artificially, we can culture cells but that's just persuading them to replicate outside the body. No regeneration involved. To make them regenerate indefinitely we need to deliberately make them cancerous so that we can study the same cell lines over long periods of time.

If you're interested in the subject I'd suggest looking into an intro to biology course, there are plenty available freely online as well as lecture series on youtube. If you're approaching it from a perspective of not understanding basic cell biology it will be hard to grasp the detail of regenerative medicine.

 

[fluidistic]

Probably this has been asked before...but...
If we know what are the causes of our death by age, why can't we overcome them, prolong our lifespan and even achieve immortality?

If we remove the effects of getting older and "freeze" our metabolism at around 25 years of age, we would still live only around 800 years in average, due to accidents, suicides and illnesses. That is extremely far from immortality.
To achieve this 800 years number one can assume that death is a Poisson process and that the probability to die at any age is not null, due to accidents, etc.
I assumed the probability to die at age 25 to be around 0.1% which is not far from reality.

In short, to achieve immortality we would need to remove accidents, cancers, heart diseases, suicides, murders and also freeze our metabolism in the sense of not getting older. You are asking why can't we overcome these events that kill us. Because it is hard/impossible and I assume we are mostly working on it although not everywhere on Earth.

 

[ChrisVer]

you are putting external factors which don't determine the immortality of the organism but its accidental death. If someone can be immortal and live for example a life expectancy of 1,000,000 years, he can as well die at the age of 30 by a bullet in his head - this doesn't rule out that he could live for 1M years.

 

[Pythagorean]

For clarity, that's usually distinguished from the colloquial usage of "immortal" by calling it "biological immortality"

 

[Evo]

Unfortunately this is behind a paywall everywhere I've checked.

The Cell Biology of Human Aging
When normal human cells grow in laboratory glassware, they eventually lose the ability to function and divide. The timing of this loss may well represent the limit of the human life span

http://www.scientificamerican.com/article/the-cell-biology-of-human-aging/

Not all cells in the human body renew either, another thing to think about.

 

[Ygggdrasil]

Here's a good (but fairly technical) review article from the journal Cell talking about some of the biological mechanisms of aging. It should be freely available to non-subscribers:

Aging is characterized by a progressive loss of physiological integrity, leading to impaired function and increased vulnerability to death. This deterioration is the primary risk factor for major human pathologies, including cancer, diabetes, cardiovascular disorders, and neurodegenerative diseases. Aging research has experienced an unprecedented advance over recent years, particularly with the discovery that the rate of aging is controlled, at least to some extent, by genetic pathways and biochemical processes conserved in evolution. This Review enumerates nine tentative hallmarks that represent common denominators of aging in different organisms, with special emphasis on mammalian aging. These hallmarks are: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication. A major challenge is to dissect the interconnectedness between the candidate hallmarks and their relative contributions to aging, with the final goal of identifying pharmaceutical targets to improve human health during aging, with minimal side effects.

López-Otín et al. (2013) The Hallmarks of Aging. Cell 153: 1194. http://dx.doi.org/10.1016/j.cell.2013.05.039