A leisurely life that begins with the possession of a game character

(This chapter has no plot advancement, so you can skip it)

If you are interested in searching for relevant information on the Internet, you can find all kinds of anti-aging secrets and information. Some are based on feudal superstition, some are based on various scientific methods, and some are based on various psychological therapies. Immortality has always been a deep pursuit in people's bones.

According to research, all settings of the human biological body cannot support low-level immortality that removes the natural lifespan limit. It is too far away from the situation where one cannot die, has no lifespan limit and cannot be killed.

For example, after putting aside all unexpected situations, the two biggest enemies of modern immortality are cancer and neurodegenerative diseases.

The essence of cancer is the infinite division of diseased cells. As long as cells are dividing, there is always a chance of errors. Although the probability of cancer cells being generated is low, if the time is extended to the perspective of immortality, cancer is 100% likely to occur.

In fact, there is no need for immortality. The average human life expectancy is 70-80 years old. Cancer has become a social problem, and 30% of people will get cancer once in their lifetime.

We don't have to live very long. As long as people can live to 150 years old, cancer will become a hurdle that no one can avoid.

Cancer treatment and immortality are contradictory in terms of current technology and theory. The renewal of human body cells is accomplished by the continuous division of stem cells.

Human stem cells have a limit to the number of times they can divide. At a certain point, most stem cells can no longer divide, which causes the body's cell renewal to fail to keep up, which is the main cause of aging.

Problems such as wrinkled skin, weak organs, osteoporosis, low immunity, etc. in the elderly are all caused by the fact that the number of stem cell divisions has reached the limit and the body is seriously lacking in healthy and energetic stem cells to repair tissues and organs.

The limit on the number of times human stem cells can divide means that the theoretical maximum human lifespan is no more than 150 years. In reality, since no one can live a perfect life without ever coming into contact with harmful substances, for most people, living without illness or disaster at the age of 120 is already the limit.

The simplest way to break through the lifespan limit is to extend the maximum number of stem cell divisions, or simply remove the upper limit on the number of divisions.

Why do stem cells have a limit to the number of divisions? It is because there is a structure called telomere at the end of the chromosome.

The principle of eukaryotic DNA replication is that the double-stranded DNA will be damaged during the replication process. Telomeres are meaningless repeated fragments at the edge of DNA, and damage will not cause any problems for telomeres.

So it can be understood that telomeres are like tires installed on DNA. Every time you drive, it is the tires that wear out, not the wheel hubs.

But the length of the telomeres is not infinite. When the tires are worn out, the wheels, chassis, and body will be worn out... It doesn't have to be the body that is worn out. When it reaches the chassis, the car will fall down.

So there is a limit to the number of times DNA can be replicated, and there is a limit to the number of times stem cells can divide. To break this limit, whether it is to increase the length of telomeres or directly remove the limit on telomere length, it is essentially related to one thing, telomerase.

Telomerase is a protein that can increase the length of telomeres. Just like the tires of a car can grow by themselves, with telomerase, telomeres can be lengthened. If cells produce telomerase themselves, telomeres can be lengthened at any time, indefinitely, and never shortened.

The inheritance of single-celled organisms, the rebirth of fertilized eggs, and the immortal HeLa cells all involve the role of telomerase.

About a dozen years ago, many people thought that telomerase drugs were miracle drugs. At that time, the shocking headlines in newspapers and magazines read: Shocking! Scientists say humans can live 1200 years! Scientists announce immortality technology!

However, at present, human beings have only a superficial understanding of telomerase. So superficial that we only know that it is very likely to cause cancer. Similarly, the principle of many anti-cancer drugs is to inhibit telomerase or resist division.

It takes two steps for ordinary somatic cells to become cancer cells.

The first step is that due to mutation, cells that have functions but cannot divide become cells that lose some functions but can divide. This step may involve many gene mutations that accumulate continuously, but it can be understood as one step.

The second step is to activate telomerase and acquire the ability to divide indefinitely. For stem cells to become cancer cells, it only takes one step, which is to activate telomerase and acquire the ability to divide indefinitely.

The most terrifying thing about cancer is not the tumor, but the fact that the tumor can divide and evolve infinitely. The concept of infinity is very important. As long as it is finite, there is always a way to eliminate it. But when it is infinite, it becomes difficult.

Telomerase is like a key that opens the door. The first thing that comes is not eternal life, but the devil of cancer.

Before humans are able to tame cancer and completely control this devil, the key of telomerase cannot be used casually.

There is also neurodegenerative diseases. Suppose one day, humans temporarily conquer cancer and can use telomerase as a key with caution.

Everyone can break through the 150-year limit and live to over 200 years old. Then we have to face the second level: neurodegenerative diseases.

Neurodegenerative disease is a general term, the most famous of which is Alzheimer's disease, commonly known as senile dementia.

The longest-lived cells in the human body are nerve cells, especially the central nervous system cells, which are the cerebrum, cerebellum, brainstem and spinal cord. The same cells are present at birth and remain at death, with almost no replacement.

In recent years, some research on neural stem cells has proved that neural stem cells exist. But their effectiveness is minimal. Moreover, for an adult who wants to live forever, his or her personality, memory, thoughts, and habits are the most important parts of the soul.

All this information is stored in the synapses. If you replace new cells, there is a high probability that most of the information will be lost.

With current technology, brain-computer interfaces can only read some thoughts or some very basic information pathways, such as desire, fear, excitement and other instinctive things. It is still a long way to go to directly write information.

So it is highly likely that in the world mentioned above where everyone can live to be 150 years old, people will at least start out using their original biological brains. They will still have the same configuration and parts as when they were born, and they will still have the same configuration and parts after they are 150 years old.

At this time, a person of that age is an "old man" whose cells are constantly renewed, full of vitality, and who has a 150-year-old brain.

Theoretically, nerve cells have an infinite lifespan. Or in other words, all cells have an infinite lifespan, but for the sake of overall planning, multicellular organisms force some body cells to undergo programmed death, while nerve cells do not have to die.

But can nerve cells really live forever? Neurodegenerative diseases come into play.

Right now, no one knows why neurodegenerative diseases occur. No one knows the cause, no one knows how it starts, no one knows how it really works.

There are some theories, such as garbage accumulated in cells and accumulation of misfolded proteins, but they are all superficial, and no one knows the real principle.