Qin Shi Huang, the first emperor of China who built the great wall of china desperately sought the elixir of immortality later in his life. As he grew older, he was terrified by the fear of death and was obsessed with the fabled elixir of youth. Unfortunately, he failed to find the elixir and died by mercury poisoning believing that mercury has the power of reversing the aging process. Now, more than 2000 years have passed since he died. The progress of science has made remarkable changes in our mode of living. Can scientists find the legendary elixir? If it cannot be found in nature, can we create the magical elixir ourselves?
What is aging?
We know intuitively what aging means, but what does it mean in the scientific term and how can we define ‘aging’? Scientists define aging as the intrinsic physiological process that declines body function and causes an increase in death rate. The mechanisms of aging are still not fully understood due to its complexity but scientists have recently made advances in this area. First, scientists have hypothesized the reasons why we age. In 1990, there was an effort to categorize 300 theories of aging by Zhores Medvedev and one of the main reasons is that cells can’t divide forever.
The Hayflick limit
In a laboratory in Philadephia, a young scientist Leonard Hayflick found out that our cells have a finite number of times – 40 to 60 times – to undergo cell division before they die and stop functioning. Once we run out of healthy and functioning cells in organs, we die. This means that we all have a biological clock that tells us when to die from the moment we are born. Why does this occur? Scientists believe that shortening of the telomeres accounts for this phenomenon. Telomeres protect DNA by acting as caps which prevent the chromosomes from deterioration. Telomeres are at the end of the chromosomes. As cells undergo cell division, telomere length gets shorter and shorter. When the cells run out of telomeres, DNA strands become susceptible to damage and this leads to cell death.
Not everything dies by aging
Does this mean that every living thing will die by aging? Not really. For example, cancer cells are biologically immortal under ideal conditions – which is not very good news for us. How about in living organisms? It turns out that some animals and plants are biologically immortal and do not die by aging. Hydra – a small, fresh-water invertebrate – is one of the organisms that does not age. In 1998, Martinez found out that Hydras do not exhibit evidence of aging. More recently scientists working at a biotech company founded by Google have discovered that naked mole rats defy the definition of aging; their death rates do not increase with age. So, by the same physiological mechanisms which hydras and naked mole rats use, can we live longer?
Unfortunately, we are neither hydra nor naked rat mole. Physiological systems of the human body are much more complicated. So, we can not exploit their physiological mechanisms. What if we can extend our telomeres and let cells divide more times? Wouldn’t we be able to live longer? The answer is a half yes. Telomerase is an enzyme that can fix and extend telomeres at the end of DNA strands. It is like a small machine that resets our biological clock. Telomerase can be found in some types of cells in our bodies – especially stem cell. It seems like a no brainer. Let’s get some telomerase and put it in a pill. Well, the problem is that’s what cancer cells do. That’s why cancer cells are biologically immortal. So, unless you want to get cancer, don’t put that extra telomerase in your body. According to Elizabeth Blackburn, nudging up telomerase could decrease aging effects, but it could also increase the risks of certain and rather nasty cancers. She mentioned that there are many websites marketing drugs saying that they can extend telomere, but the problem is those drugs could nudge up the risks of cancers. Here is a major dilemma, cancer or aging?
(Video – Ted: The science of cells that never get old by Elizabeth Blackburn)
So, there is no clear solution to aging yet. However, a journey of finding the elixir of immortality continues. Scientists keep on pouring tremendous efforts to understand aging and how to resolve the riddle of the true antiaging drug. Instead of making the drug, there could be other ways to approach the immortality. Netcome, a neuroscience startup that seeks to back up the human brain on the computer server. Biolife4D, a biotech company in Illinois, United States is trying to build human organs with stem cell technology and 3D bioprinting technology. Maybe in the near future, we will figure out an answer to the immortality.