Biological ageing and the price of immortality
The quest for life
One of the biggest psychological struggles for adults is the concept of growing old and inevitably having to come to grips with our own mortality. Unfortunately the molecules in our body just aren’t stable in their current configuration, and as entropy tightens its grip our bodies break down and return to the soil from once we came. Despite this being the natural order of things we are fully prepared to fight off nature with a pointy stick to the bitter end.
If we ignore the financial aspect for now, in a sense it would be safe to say that the majority of medical research is geared towards one goal – to increase the longevity of the human race, and it seems to be working. Had you been born in 1850 you wouldn’t be expected to live past 45 years old. Although the increase in life expectancy has slowed slightly in the last few years it only takes one major medical breakthrough to drastically change life expectancy such as the discovery of penicillin and the development of vaccines.
Of course things have gotten a bit more high tech since the discovery of antibiotics. Advances in genetic research are allowing us to unlock the secrets of our own mortality. This is however a very slow process. This is because ageing doesn’t have a single cause. While there are many articles out there with gripping headlines such as “A Molecule That Turns on the Immortality Gene!” I can assure you that stopping the biological ageing process is not just a matter of flipping a magic switch within our genome on or off.
While we are good at treating diseases that come from an external source such as infectious diseases, pathologies associated with ageing such as cancer or neurodegenerative diseases are intrinsic; they can’t just be expelled from the body and this poses a greater challenge for medical research. This is not of course to disparage the efforts of the scientific community who work on these issues. Great advances in knowledge and potential treatments for these diseases are being made, but when it comes to the physical process of ageing, things get a bit trickier.
One of the most significant breakthroughs in our quest for the fountain of youth was the discovery of telomerase a protein that prevents the shortening of caps on the ends of our chromosomes called telomeres. These telomeres contain unused DNA which protects the rest of the DNA that we do need from damage. Each time a cell divides the proteins that replicate the DNA can’t make it all the way to the end of the chromosome so a little bit is lost each time. The presence of telomeres means that in a healthy cell only a little bit of the telomere is cut off each divide, leaving the rest of the DNA intact. Telomerase is present in high quantities in the cells of so called biologically immortal species such as Lobsters. Unfortunately telomerase isn’t present in human somatic cells.
This theory of anti-ageing makes sense as the telomeres in the cell shorten each time the cell divides. This means that the life span of a cell line is finite, as eventually the telomeres will diminish and trigger apoptosis where the cell essentially commits suicide for the greater good. This process is known as the Hayflick limit. If this is done inefficiently then DNA will be chipped away, damage will occur, and errors in our DNA will begin to emerge causing diseases such as cancer. In old age this becomes a more frequent occurrence and the body finds it difficult to replace these cells leading to the degradation of tissue.
The telomere theory of ageing however is incomplete. Other factors have been implicated in ageing such as oxidative stress, cell membrane degradation, intracellular and extracellular junk, and extracellular matrix stiffening to name a few. This isn’t to say that all these factors won’t be treatable in the future, but it would by no stretch be a magic pill. It would require multiple treatments and these would all have be done repeatedly to maintain this theoretical state of youth.
Immortality comes at a cost
Is there a limit to which we should be increasing our longevity? Both the ever increasing life expectancy we are facing and the hypothetical biological immortality scenario pose problems.
An increase in life expectancy doesn’t mean an absence of health problems or an increase in quality of life. Our ageing population is costing the National Health Service more and more every year and pushing up health insurance premiums in the US. On average people aged 65 cost the NHS two and a half times more than a 30 year old and people aged 85 cost over five times as much. In fact in the last 15 years life expectancy across 191 countries has gone up by 10.1 years but the average healthy life expectancy has only gone up by 6.1 years, meaning that people are living longer with illnesses. Additionally since people are living longer in old age, pensions need to last longer meaning they cost more, this also means that the age people need to be to collect their pension continually goes up. My current pension age is 68. If I were a tree surgeon could I be expected to be climbing trees and humping around logs at the age of 67? I would of course have the option of changing careers but it may be hard to enter a whole new area of work in my 60s when I would have to contend with well qualified applicants in their 20s and 30s.
If we were to hypothetically eradicate ageing all together it may decrease susceptibility to disease but is doesn’t make us immune, meaning people could be living permanently with debilitating or painful diseases, consequently health care may need to be provided for them permanently. Not only would this biological immortality lead to gross overpopulation but one can only assume that it wouldn’t come cheap. Who‘s going to pay for the cure for death for 7.4 billion people? There could be national schemes among the wealthier countries however I can’t imagine poverty stricken provinces forking out the cash to the slums. This would of course destroy the world economy as suddenly there are no poor people to exploit. After all who in the western world is going to make sneakers for £0.26 an hour?
I am of course being very sceptical about a strictly hypothetical situation, however I feel the immortality scenario reflects some issues that we are already facing both in our health service and in the way we think, both as scientists and as the public. It is easy to get swept away in the romance of promises for future immortality or curing the incurable, but what then? Life is fragile and we instinctively do whatever we can to protect it. But there may come a time when we have to make decisions about life that we haven’t had to before, and for this we should be prepared.
