대학신문방송국

How to Overcome Aging

By Lee Woo-seung Cub Reporter, Junior of Mechanical Engineering

Everyone knows that health is very important in our lives. However, many people overlook the importance of health until they lose it. Today, the average person lives to be much older than those who lived decades ago. This may sound like very good news, but the time to live with disease has increased as well. Recently, scientists have been trying to shift their focus from "Life span" extension to "Health span" extension. This means that we can increase our time on earth while being free from disease. To do this, scientists have put a lot of effort into finding the root cause of conditions that have a negative effect on our health. As a result, over the past few years, research on aging has made tremendous advances to the point where clinical trials are possible in the near future. 

SENESCENT CELLS

There are three issues that would be good for you to know about aging, the first is "senescent cells." Every cell has an expiration date. Cells copy chromosomes when they divide. Because of the way this works, they lose a tiny bit of DNA at the ends. This could be catastrophic, so to protect against this we have long segments of DNA called telomeres. However, this also shrinks with cell division. In some cells, after a number of divisions, the telomeres are gone and they are unable to function properly. These cells are what we call senescent cells. Senescent cells stay around and don’t die. The older you get, the more of them are inside you. The problem here is that senescent cells damage surrounding tissue and cause various diseases, resulting in aging. Is there any way we can get rid of these senescent cells? Scientists have applied genetic modifications to mice that can kill aging cells on their own. Older mice without senescent cells were more active. Their hearts and kidneys worked better, and they were less prone to cancer. While most cells are designed to kill themselves when they are heavily damaged, senescent cells are not. This is because proteins in the cells command suicide, but senescent cells do not produce enough protein. In a late 2016 study, protein was injected into mice. The injection killed 80% of the senescent cells and the mice became very healthy. As a result, there are a number of new companies looking at treatments involving senescent cells. 

STEM CELLS

The second is the "stem cell.” Stem cells are everywhere in the body and replicate to supply new cells. Stem cells are needed for an embryo that is not yet fully grown to develop properly. However, they are also necessary for the adult body to supplement new cells. In a stem cell experiment, scientists took the stem cells from a young mouse and gave them to an old mouse. As a result, the new stem cells injected into the old mouse helped the metabolism, causing the old mouse to find vitality. In another study, embryonic cells were injected directly into the heart of an old mouse. As a result, this mouse lived longer than ever before, and hair in missing areas grew anew.

NAD

Cells are made of hundreds of millions of parts. All these parts constantly need to be destroyed, cleaned up, and rebuilt. However, as we get older, the efficiency of these processes decreases and eventually do not meet the production our bodies need. One of these parts is NAD, short for nicotinamide adenine dinucleotidea, a coenzyme that plays a role in maintaining the metabolism. At age 50, we only have about half as much NAD in our bodies as we did at age 20. Decrease in NAD causes various diseases. But, NAD can’t enter cells so we can’t get it as a pill. Scientists noticed that other more flexible substances could enter cells and would then turn into NAD inside. In 2016, multiple trials on mice showed that they boosted the multiplication of skin, brain, and muscle stem cells. Therefore, scientists expect that NAD will serve as the first real age resistor for humans.

WHAT SHOULD WE DO? 

As described, there are various ways to prevent aging. Killing senescent cells, using stem cells to fill the void, and controlling the metabolism of healthy cells using drugs are some of the ways scientists are researching. However, one of the biggest problems is that so far it's only been applied to mice. There is no guarantee that any of these experiments will have the same effect on humans. What this shows is that we should not expect a breakthrough any time soon, so we should continue to work to ensure successful aging.