Biochemistry - Aging Process

Aging is the process in which our body grows older, with observable side effects. Much of our research today has been focused on how to counter these effects of aging. Firstly, however, it is important to know the exact effects that aging may have on our bodies.

For most of us, when we think of aging, we think of grey hair, wrinkled skin, or a feeling of weariness. However, in reality, aging is a combination of several factors. Genetics have much to do with the process of aging and how long a person may live. When people start to age, “...our cells become less efficient and our bodies become less able to carry out their normal functions. Muscles lose strength, hearing and vision become less acute, reflex times slow down, lung capacity decreases, and the heart's ability to pump blood may be affected. In addition, the immune system weakens, making it less able to fight infection and disease”. Scientists have two theories about how our bodies age. One of these theories is that people have, planned in their genetics, how long they are expected to live and when they will die. Support for this theory has included experiments in which cells have been shown that cells will only replicate about 50 times before they die. The idea is that after they’ve stopped their divisions, the body begins to wear down and eventually die. Another theory has been that natural life processes wear down our bodies, such as ultraviolet radiation from the sun, X-rays, and chemical toxins. Mutations may also occur in our bodies. If the DNA is damaged or is being replicated, repair mechanisms that are put in place may fail, and mutations may occur. Some other processes that may contribute to aging/death are protein damage from cross linkages, or faulty bonds that may form in proteins (See Figure 1). One of these proteins is collagen, which is a type of connective tissue which helps support organs and blood vessels. This could also be caused by a buildup of free-radicals (normal chemical products from the usage of oxygen).

Figure 1

Some of the common effects of aging on the body include effects on people’s digestive system, nervous system, skin, and skeletal system. In the digestive system, there may be a loss of teeth. However, this is usually due to neglect, not aging. The production of hydrochloric acid in the stomach for digestion also decreases with age, which may result in a slight increase in fat absorption. In the nervous system, as people grow older, our productions of neurons have decreased. For the elderly, their neurons may begin to degenerate, which leads to a loss of memory sometimes. There may also be impairments in sensory organs as well, like loss of sight, hearing, smell, etc. As people grow older, their ability to remain focused or switch the focus of their eyes gradually decreases. Therefore, night vision is reduced in the elderly and they need more light to see. Hearing is usually affected also, as the elderly cannot hear as many high pitched noises. Usually, they will hear at tones at or under 10,000 cycles per second. Their smell is usually affected by other outside factors, like, for example, if they’d been a smoker or around someone who smokes. Finally, their taste is eventually affected as they experience a loss of taste buds as cells stop dividing.

Current research is undergoing progress as new techniques are being discovered to reduce the effects of aging. Teet Seene and Priit Kaasik published their article, “Age-Associated Changes in Skeletal Muscle Regeneration: Effect of Exercise”, a study conducted in November of 2015. They researched the effects of muscle proteins on aging and how they could potentially be harnessed to alleviate the process. The article details that, “Skeletal muscle fibers have a remarkable capacity to regenerate, and this depends on the number of satellite cells under the basal lamina of fibers and their oxidative capacity”. A decrease in satellite cells may lead to an increase in the response time of the patients, as observed in the lab by experimenting on rats. These satellite cells may be eventually harnessed to help the effects of aging. The buildup of these cells are due to a combination of both external and internal factors which affect skeletal muscle regeneration. According to scientists Seene and Kaasik, “Aging induced sarcopenia is a result of decreased synthesis and increased degradation of myofibrillar proteins, which leads to the slower turnover rate of muscle proteins, especially contractile proteins, and this, in turn, leads to the decrease in muscle strength”. Basically, sarcopenia, which is the eventual loss of muscle is due to an imbalance between the proteins of the body and the process of degeneration. Exercise would increase the body’s muscle oxidative capacity and contractile properties. One can read more at the url, http://file.scirp.org/pdf/AAR_2015112315001729.pdf, or under the article title.

References: 

http://www.scienceclarified.com/A-Al/Aging-and-Death.html

https://www.britannica.com/science/human-aging

http://file.scirp.org/pdf/AAR_2015112315001729.pdf

Picture: 

http://daltonlab.iqm.unicamp.br/figuras/XL_MS.jpg