Glenn John S. Guerrero
Carlo Martin P. Selera
Mr. Angelo O. Tubac
March 17, 2011
EFFECTS OF STRESS ON SKIN DETERIORATION
The skin provides the first line of defense between the body's interior and harmful environmental insults by well-established physical and biochemical mechanisms. Physical protection mechanisms include the relatively impermeable barrier the skin provides. The skin can, to some extent, repel and absorb insults such as chemicals and ultraviolet light so that while the skin may be damaged, the underlying tissue is preserved. Biochemical mechanisms include the innate and acquired immune systems. The continuous mutilation, however disables the tissues to redevelop and will lead to the skin deterioration. Deterioration of skin leads to changes in dermal thickness and elasticity due to increased crosslinking of collagen. Epidermal regeneration increases in activity while metabolism, sweat glands, and vascularization, all decrease in activity. The damage from internal and external factors is progressive and cumulative and results in the appearance of deterioration associated with aged skin. Structurally, Denda, M. affirmed that the mechanisms of skin deterioration involve a gradual and progressive process that begins from birth (314). Internal factors that contribute to skin aging include toxic metabolic byproducts, autoimmune diseases, and genetic predisposition. The consequences of internal deterioration can be observed over the entire body from the skin to the internal organs. While the mechanisms of internal deterioration are not completely understood, somatic mutation has been shown to be a contributing factor. Under the somatic mutation theory, cells gradually lose their youthful characteristics and their capacity to divide by the accumulation of mutations (errors) in their genetic code. These mutations may be caused by free radicals or alkylating agents generated in metabolism that lead to unrepaired DNA damage. Over time, mutations accumulate in the body until the cell can no longer divide or produce functional proteins. Related to the somatic mutation theory, both internal and external factors contribute to oxidative stress, which in turn results in DNA damage. In humans, oxidative stress and DNA damage is caused by factors such as hyperbaric oxygen, gamma radiation, ultraviolet radiation, ozone, peroxides, free radicals, alkylating agents, and redox cycling drugs. While total oxidative stress and DNA damage may be reduced by living in a low pollution environment and avoiding sunlight, they cannot be eliminated. Some factors like ionizing radiation are present in all environments at a low level and other factors are byproducts of metabolism and cannot be totally eliminated. Further, urban environments have high levels of ground level pollution from a variety of sources that are not likely to be reduced in the near future. However, while DNA damage cannot be avoided, not all DNA damage leads to mutations. DNA damage does not necessarily lead to mutation because a normal cell contains diverse and effective systems for repairing damaged DNA. There are at least 50, and possibly more than 100 genes involved in DNA repair. The importance of good DNA repair in retarding skin deterioration is most noticeable in patients that suffer from DNA repair defects such as xeroderma pigmentosum (XP). XP have early and accelerated skin deterioration, clearly demonstrating the importance of DNA repair to reducing deterioration of the skin. In addition to DNA repair, a normal cell also has systems that invoke "programmed cell death" by a process termed apoptosis. The process of apoptosis effectively "erases" cells damaged beyond the point of repair. These natural defense mechanisms of the skin have been ignored by current methods of preventing skin deterioration. Obviously, external factors such as chemical and physical agents in the environment can cause DNA damage that leads to skin...