Why Do We Age?

Did you know that there are certain species on the face of the Earth that are truly and literally immortal? Yep. They never die. Of old age that is. I am not talking about some microscopic bacterial life or stubborn viruses in existence. No. Real animals. Take these two: turtles and lobsters. They literally don't age. When it comes to first one, I can't resist not to quote article in below refs* I read online - to the logical suspicion of endless turtle lifespan and why in aftermath they don't crawl everywhere we look today, they answer: "Of course they die, otherwise we'd be swimming in turtles, but the weird thing is, they never seem to die of old age. It's always a disease, or a falling boulder, or Master Shredder". And this is a real truth actually, including 'Master Shredder' who might be just a metaphor for us killing turtles for food or purses and belts or whatever we do with dead turtles. Joking aside, the very research of big turtles shows no evidence that their body change or mature after they pass teenage years. They are literally capable of sexual reproduction until the end of time. And again the glimpse from the noted article stating the obvious: "They can breed and lay eggs until the day they drop dead and that means that, technically, a turtle can live and have sex forever". The same is with lobsters - well I am not sure about the sex thing, but they don't age either. Just grow bigger and bigger and bigger until they finish their lifespan in i.e. kitchen of some fancy restaurant. When they got so big that their shell can't sustain them anymore, they just get out and start growing a new one. I am sure somewhere out there in the bottom of some sea or ocean there are lobsters today old enough that are actually living witnesses of Darwin's "Beagle" sailing out for her historical voyage around the world in the early nineteenth century.


I am sure by now you already started growing an ultimate regret of why on Earth you didn't born on one of Galápagos islands, hatched out from some egg and spend eternity in practicing marshal arts - and instead ended up to be a human. But seriously the title's question is real and open for scientific discussion. And for theatrical purpose let me repeat it: "Why do we age?" And ultimately die? Surely, if we find out why, the next question is of course, can we cheat it? Expand it? Live forever? If we find out that is possible, third question in the row imposes. Should we do it?

But, before we dive into deeper thoughts and evaluate leading theories and hypotheses, I remember when I started with a blog, one of my early small post in humor thread was couple of famous quotes about life itself. As far as I remember, many of them were really a plain and intelligent jokes but the one said by Ronnie D. Laing, a Scottish scholar who dedicated his life in research of mental illness and psychosis, was probably hitting the target in the bullseye. He said: "Life is a sexually transmitted disease and the mortality rate is one hundred percent." If we extract the humor from this one-liner, what we really get is, perhaps, the ultimate truth. Reaching yours or mine old age, or death itself, might be nothing else than a genetic disease, in a stretched form of the definition of the word 'disease', and we might be able to do something about it.


Well, contrary to lobsters and turtles (and some other 'immortal' species like certain type of whales, seashells, sponges, hydras, etc), we are mammals, pretty different kind of anim.. ahem, species. We are different in many ways, genetically speaking and comparing to, for example, reptiles we cannot re-grow our teeth or entire body parts as well, and our DNA, as it seems has limited regeneration ability that fades with years and ultimately got exhausted the moment before death. For those lucky to die of old age.

Two leading theories are posted until today. First, it was proposed that living organism have some sort of genetic expiration time, written in DNA. In other words, we are all combination of genes of our parents and their parents and parents before them, all the way back in history of our families and this lucky mixture of genes, written in all of our cells are built to last only limited period of time. Even though this theory seems so unbelievable and far-fetched, it is actually hinted in labs. In some genetic research of worms, altering their genome and some specific genes, 'produced' the worms who actually lived four times longer then their unaffected peers.


If those genes with encoded expiration date really exists, finding and re-writing them might be able to increase our lifespans. However, the second theory is much more appealing and easier to understand. It simply says that our cells dies at the end of the cycle due to too much damage they suffer over the time. To simplify it, there are two types of DNA in our cells, nucleus DNA, that defines us, located in the cores of cells and mtDNA, residing outside nucleus and in special parts of the cells called mitochondria. While nucleus code is used during the cell's division to produce another cell with the same DNA, mtDNA is there mainly to produce energy for the cells from the food we consume. And both DNAs can be damaged in time due to various factors and as time passes over years and decades the damages become more severe and in the end of the process we know as aging entire organism dies. If we focus on mtDNA first, it's logical that these 'power plants' of our cells endure way too bigger pressure than their fellow DNA in nucleus, as they are in the first front lines hit by influences of the food we eat. From that food they produce energy and in the process a very bad byproduct called ROS or 'Reactive Oxygen Species' or simply 'free radicals', which are variety of oxygen based molecules that are very dangerous for the power plant itself and very capable to ultimately damage the cell and mtDNA to the point of full destruction in the process of unwanted mutations. Basically if you are now thinking that special sort of diet or simply eating less food would give you longer life, think again. In fact, if you do so, it is logical that more DNA in mitochondria will survive over time in their intact form, but on the other side restricted diet in lab animals shows that they grow slowly than normal, reproduce less than normal, and with endangered immune systems than usual. We need food. It is essential. So, don't stop eating but try to do it properly and in the most healthy way possible. But the theory of lifespan directly related to the healthy mtDNA is proven in poor lab mice in which scientists encoded a faster genetic mutation of mitochondrial DNA which resulted in faster aging and shorter lifespan - they actually lived three times shorter than their 'normal' friends and cousins. So oxygen is bad and ultimately kills you. And yet we cannot live without breathing, can we? A paradox of creation, especially if you are a believer.

What about nucleus DNA in our cells? Are they also causing aging in the process of mutation? Yes, due to mutation of nucleus DNA cells ends in cancerous or non-cancerous state which is pretty much a defect and cell's death. During an organism growth, cells divide in the process called 'mitosis' - one cell by using code in nucleus DNA divides into two new cells which are exact replicas of the parent cell. Even after organism fully matured into its adult stage, cells still continue to divide for the purposes of reproduction and replacement of lost or dead cells. However as it seems, both resulting cells are not really and exactly the same as their predecessor cell. Yes, the code in chromosomes are the same, but the ending caps of the chromosome structure are getting shorter after each division. These caps are called 'telomeres' and their main purpose is to protect the end of the chromosome from connection with other chromosomes. After numerous division of the cells, telomeres runs out and this is pretty much the end of it. The cells are after that doomed. But this is not the end of all the ways of one cell doomsday scenario. According to Aubrey de Grey, one of the leading scientists in Biogerontology, the scientific sub-field of gerontology concerned with the biological aging process, over the years the cells accumulate various molecules that are no longer useful and potentially harmful. And not just within the cells, but also in the space outside cells. Those molecules are scientifically called 'intracellular and extracellular aggregates' but their real name are 'junk molecules' and like the name suggests, the more of accumulation of junk, the more dysfunctional the organism becomes. Dr. Aubrey de Grey proposed even more processes, on the cell level, influential in aging and thanks to his research and entire scientific mainstream, which is still ongoing research, we definitely understand it more then ever.


Benjamin Franklin once said that in this world nothing can be said to be certain, except for death and taxes. I, for one, would definitely like to see the end of death and taxes for sure, and even though it is very hard to imagine a world without taxes, the death after all might be very different story. Well, understanding the aging is one thing and finding the cure for it is surely another, not to mention manufacturing a 'cheating-death' pill is not really in the realm of possibility anytime soon. Even the 'genetic pill' that will be able to slow down aging or the one capable of reverse-engineering that would replace mythical fountain of youth (or Lazarus Pit from DC Comics franchise) are far away from the horizon. However, what is on the horizon and even much closer is the effort and research. Last year Google announced a plan to invest lots of money into California Life Company, aka Calico and if you go to their website first thing you will see is their motto "We're tackling aging, one of life’s greatest mysteries." If you dive into current stage of IT leading entrepreneurs and futurist, it seems they all are sharing the same enthusiasm in the "curing death" realm and I can't help myself but stating similarity with the A.G. Riddle's new novel called "Departure", which pretty much influenced me to write this post, even though I was planning it for a while. I will not spoil the reading for you, but in the nutshell, one of the background story in it is dealing with immortality which, in one way or another, resulted in end of civilization as we know it. I am encouraging you to read the book - it is definitely one of the best novels of the year in sci-fi realm. In short and in the aftermath related to immortality, one of the leading characters from the novel, Sabrina Schröder was portrayed giving TED talk about cheating death and why we should avoid it in great scales. That's all I would say, sorry but you would have to read entire book to understand everything. I will just say that I hope Riddle's 'Titans' are not prediction for 'Googlers' or 'Applers' or 'Calicos' or whatever the name they come up with in the upcoming breakthroughs in aging research.

As for me, I am sure I wouldn't mind to prolong life a bit, or a little bit, or a 'frakking' long bit, but avoiding death is raising lots of other dilemmas in morality and everything else. It could be handy on a long inter-stellar voyages though but it is not far from the truth that reproducing and further evolution of humans would be in real danger if everybody took the immortality pill and if we stuck in current stage of evolution without offspring of any kind. Morality issues of a potential cloning of a human being and making it immortal might not be too different.


Extending the lifespan is a very different story. I would always take the red pill and jump into rabbit hole without hesitation. The life is way too short. After all, lifespan is something nature and evolution are working on for centuries. People in the past lived shorter than we are living today and people of the future might live way above 100 years in average. If we learn to push and help a little with science, I would definitely be aboard.

Refs:
http://www.calicolabs.com/
http://www.medicaldaily.com/cure-aging-google-plunks
http://www.telegraph.co.uk/.../trying-to-cure-ageing.html
https://en.wikipedia.org/wiki/R._D._Laing
http://genetics.thetech.org/original_news/news10
http://www.todayifoundout.com/index.php/2014/05/age/
http://www.agriddle.com/departure/sabrina
http://www.agriddle.com/Departure
* http://www.cracked.com/animals-that-are-immortal.html
http://www.aboutdarwin.com/voyage/voyage03.html

Image credits:
http://nocamels.com/2013/12/stop-aging-to-prevent-alzheimers/
http://nocamels.com/2015/06/genetic-sequencing-evolution-cancer-brca1/