To live a hundred years is not that difficult, as some individuals prove. In theory, we could live for centuries. Many scientists are working on this dream, but so far there are not many successes. Does anyone your age have a chance to live hundreds of years? Will generations younger have such a chance? The issue of a long life and, what is important, a healthy life, worries many in the field of biology and medicine. Molecular biologists, geneticists, nutritionists strive for the ultimate goal - to delay the appearance of senile diseases, and then completely eradicate them.
And while reducing the burden of disease is a public health goal that motivates governments and medical communities to conduct research on aging, it is long life - the search for the elixir of eternal youth, immortality - that captures the imagination.
Aside from wars, famines, or major economic disasters, human life has grown steadily across the world over the past century. Life expectancy in Australia is around 83 years, the fourth highest in the world. These benefits are largely due to improved access to health care and its quality. We have yet to see the impact of treatments designed specifically to treat aging, and this could lead to increased life expectancy.
What the researchers are working on
Most of the so-called "herooprotective" compounds that are currently being developed mimic the effects of calorie restriction or exercise. Lifelong calorie restriction, cutting calorie intake by about 30% is one of the most powerful interventions known to extend lifespan.
Over the past twenty years, research on aging has sought to determine which genes and molecular pathways are turned on and off when dietary restriction and exercise increases. This led to the discovery of a number of pathways (called sirtuins, insulin / IGF-I signaling, mTOR and AMPK) that can be used to manipulate animals and prolong their lifespan. The antidiabetic drug metmorphine activates one of these and is also being tested as a health-promoting agent in old age.
Another way to prolong life is to remove the senescent, or old and damaged, cells that cause disease. But here's what is important: these paths can extend life by only 30%, so that from the "normal" life span of 83 years, we will only live one century.
Promotional video:
While living more than a hundred years will be a huge achievement anyway, it is not nearly the centuries that people dream of. To achieve this goal, old age biologists will have to go beyond limiting calories, altering metabolism, and flushing out old cells.
Possible future directions
Instead, we can look for inspiration in nature. The hydra jellyfish does not show noticeable biological aging and is functionally immortal, most likely due to the high content of stem cells that can replenish the adult body. Another species, Turritopsis dohrnii, the "immortal jellyfish", can transform an adult body into a youthful state, and then mature again, repeating this cycle almost indefinitely.
How do we fake the immortality of a jellyfish? To begin with, we could reprogram our "epigenomes," the constructs that keep different parts of our DNA code on and off. Curiously, we already know how to do this. There are only four genes, "Yamanaka factors", that turn adult cells into embryonic stem cells, like Benjamin Button, who turns from an old man into a baby.
In theory, incorporating these factors at the right time and in the right place could rejuvenate our bodies. In theory, we could live for centuries.
The problem is how to figure out when, where, how much and how much to include these Yamanaka factors. Overexposed and the organs can turn into a mass of undifferentiated embryonic stem cells that can grow into the wrong type of tissue. To underexpose - and there will be no effect. You need to find the right dose. Human testing would be too risky.
It should be remembered that extending life span is not in itself the same as extending quality of life or healthy years. There is no need to postpone death by making the periods of illness longer. The ultimate goal should be to reduce the amount of time people are unwell.
At some point before death, everyone crosses the threshold of independence, a healthy and active state, becomes dependent, sick and inactive. How much time we spend on overcoming this moment - this figure is different for everyone, but everyone agrees that it should be minimal in comparison with healthy years lived by a person.
Lifestyle changes, advances in technology and medicine are all aimed at maximizing the proportion of time spent living and delaying the (inevitable) occurrence of aging-related diseases. But to live for centuries is a dream for the time being.
Ilya Khel