Whether you like it or not, you are going to age. You are going to reach a point where you start forgetting your friends and family. With time, wrinkles will start gradually showing on your skin, your vision may also deteriorate. Many physical changes happen as you age, but what cause all these changes? What makes you age? Can we reverse aging? Can we prevent aging?
For many years, scientists struggled to solve this mystery. But they were able to come up with some reasonable theories that might explain this phenomenon.
Spontaneous Mutations:
This type of mutation occurs naturally, and is not as a result of exposure to mutagens. When such mutation happens, it may alter protein sequence which might cause a defect in the DNA. Some of the causes of spontaneous mutation are nuclear radiation – such as the one hit Nagasaki in Japan-, exposure to ultraviolet radiation which might cause skin cancer. Chemotherapy treatment of patients who have cancer, might also cause mutation. For low levels of radiation exposure, the biological effects are so small they may not be detected. Our body has repair mechanisms against damage induced by radiation as well as by chemical carcinogens. However, some patients get exposed to relatively high levels of ionizing radiation which might lead to the development of several types of cancers.
Free Radicals:
When body cells create energy (by the mitochondria), they also make unstable oxygen molecules called Free radicals. Free Radicals have a free electron which makes the molecule highly unstable. Free radicals are harmful if found in the body in a large quantity. But if we eat enough plants, then the Antioxidants (found in plants) would soak those free radicals and reduce the damage cause by them. Free radicals are known to Change DNA replication and fidelity, Decrease fluidity of lipids and break chromosomes. (Just to name few).
Wear & Tear:
As we get older, our body cells get damaged due to their use over time. Basically, our body systems wear out due to use and they can no longer function correctly. Osteoarthritis is classic example of wear and tear theory of aging.
Immune System:
Our immune system relies on many organs and cells to fight foreign objects that might enter our body. One of these cells is (T cells). Some of the T cells directly kill foreign particles. Others help coordinate other parts of the immune system, which are specialized to attack different types of infections. Even though the number of T cells in our body doest not decrease with aging, T cells function decreases. This would cause parts of the immune system to weaken. When the immune system gets weaker, it loses its ability to fight off infection as we age. Moreover, in a later age the immune system also seem to become less tolerant of the body’s own cells. Sometimes autoimmune disorders occur.
Cellular Senescence:
Hayflick
Senescence cells are the cells that lost the ability to reproduce themselves. when cells become senescent, their DNA get damaged or altered as a result, senescent cells secrete abnormally large amount of some proteins that are harmful to their neighbor cells, stimulating excessive growth and which might damage other cells. Cellular senescence is explained to us by the Hayflick’s phenomenon. Hayflick’s phenomenon or limit, say that normal diploid cells lose the ability to divide, normally after about 50 cell divisions in vitro.
