Will human life expectancy double by 2050?

I just read Raymond McCauley’s views and arguments on the Internet. Let me share my own views.

One way to extend lifespan is to delay cell aging. This requires cells to be exposed to as little adverse environments as possible, and also partly explains why high-quality lifestyle habits such as quitting smoking and drinking can prolong life. However, on the one hand, it is sometimes difficult to find a completely "ideal" environment, such as an environment that is completely free of pathogens. On the other hand, even in this environment, some cells will still undergo apoptosis (although it may be a little slower than in the natural state). For example, the lifespan of B cells is between a few days to more than ten days, and the lifespan of T cells will be longer. Same for several years. Although some cells (such as neurons) are not easy to die, or their "natural lifespan" is longer than a person's own lifespan, due to the "barrel principle", when an important organ or system's cells are almost completely lost, the person's Just "dying".

The second method is to promote cell proliferation or tissue "regeneration". However, the number of proliferations of the cells themselves also has corresponding limits, which has also been confirmed during in vitro subculture: too many cells will become less and less likely to be passed on. Some of these cells may even develop into cancer cells. On the other hand, in the process of human growth and development, some cells have partially or completely lost their ability to divide after differentiation. Generally speaking, the higher the degree of differentiation, the lower the ability to divide.

One direction of current biological research is "reverse differentiation", which is to induce differentiated cells to return to an undifferentiated state (stem cells). It is said that certain progress has been made in this aspect.