Theories of Aging
When theorizing the why and how of aging in relation to biology, I was most struck by Arbuthnott et al.’s (2016) discussion on evolutionary theory and aging. The authors’ main aim was to explain why mortality rate rises with aging. One thing that stood out for me throughout the discussion revolves around the fact that Senescent is a characteristic of life that occurs because selection is weak and cannot maintain the survival of an organism.
Arbuthnott et al. (2016) further emphasized that aging evolves since selection cannot effectively eradicate detrimental mutations that occur during late stage of life. This prompted me to conduct additional research regarding the same and the findings termed this as the mutation accumulation hypothesis. It emerged clearly from the discussion that aging shortens lifespan which, in turn, is shaped by selection for a high number of long-term reproductive events. In essence, aging is associated with the reduction in the force of natural selection as it relates to mutation that generates negative effects in later stage of life.
Another thing that struck me the most when theorizing the why and how of aging is that Senescent is a side effect of genes that are involved with fertility and fitness. In this regard, aging occurs because the advantages of enhanced fertility during middle stage of life are connected physically to prolonged deterioration of the body (Bengtson and Settersten, 2016). In other words, aging is linked to enhanced survivability during early stages of life but this correlation is not always consistent. In addition to this, there is underlying inflammation that interferes with the skin’s defence mechanism (Xu and Kirkland, 2016). This in turn weakens skin structure which leads to degradation of collagen and elastin.
Scientific Discoveries
Theories of stem cell aging hold that the senescent process is marked by the inability of different types of stem cells to plenish the tissues of an organism with healthy ones. Therefore, the scientific discovery that I find most compelling revolves around the theories of stem cells advanced by Sousa-Victor et al. (2016). The authors discussed how scientists have been able to rejuvenate old satellite cells such as those related to geriatric age. The aim has been to restore traits of youthfulness with the objective of maintaining human health during aging. The interventions that delay the process of aging prompted scholars to conduct further research on systematic regulators of immune homeostasis.
Another discovery that I find compelling revolves around how aging leads to the loss of tissue and skeletal muscle function. For instance, the authors noted that skeletal muscle has unmatched regenerative capacity that depends largely on its satellite cells. However, this capacity tends to reduce with aging and the recent scientific discoveries shows why this occurs. One discovery showed that degenerative capacity declines due to age-related environmental and autonomous changes.
Troubling Issues
Senescent, according to the theories of stem cell aging, occurs when the cells grow old due to factors such as DNA damage. However, the issue that I find most troubling is the use of stem cells to delay aging process as evidenced in the discussion by Sousa-Victor et al. (2016). The main issue of concern is that the focus is generally on achieving a healthy lifespan as opposed to total lifespan. Delayed aging will work only if there is prospect towards restoring people to a physically sound and healthy status.
Reference
Bengtson, V. L., & Settersten Jr, R. (Eds.). (2016). Handbook of theories of aging. Springer Publishing Company.