|Skin in Health and Disease|
Skin aging and accumulating skin deformities can be attributed to intrinsic and environmental factors. Makrantonaki et al described the environmental aging effects on the skin: “Aging is a complex process not only influenced by inherited but also by several environmental factors. It is characterized by a progressive loss of function in multiple tissues, which leads to an increased probability of death. On the other hand, several morphological and histological changes are registered in aged skin that is mostly dependent on the cumulative exposure in environmental aging promoters, such as ultraviolet radiation. Sex hormones, thyroid and growth hormones play a role in maintaining youthful skin conditions and skin aging accelerates with decreased hormone production. The two worst environmental aging factors are tobacco smoking and ultraviolet light from the sun. Smoking tobacco accelerates skin aging. The most obvious effect is increased and premature wrinkling of facial skin. We assume that our readers do not smoke or will quit smoking as soon as possible if they are genuinely interested in their health.
The intrinsic aging factors begin with an aging program in DNA that we cannot avoid. Some people are blessed with good genes that allow them to look younger longer as long as they pursue a healthy lifestyle. Others are not so lucky and develop gray hair and skin wrinkling earlier in life.
Repeated exposure to UV radiation from the sun causes premature skin aging. Photoaging is becoming more important as people live longer with increased sun exposure associated with leisure time, outdoor recreational sports, sun bathing and holes in the ozone layer. Photo-damage begins in infancy; 50% of an individual's ultraviolet light exposure occurs before the age of 18 years. An epidemic of the most dangerous skin cancer, malignant melanoma, is already underway. Some predict that skin cancer will become the most common type of cancer and malignant melanoma will become the leading cause of death from skin cancer.
Photoaging is characterized by wrinkles, mottled pigmentation, dry and rough skin, and loss of skin tone. A deficiency of superficial dermal collagen is one cause of photoaging. In one study, the degradation of endogenous type I collagen fibrils was increased by 58 percent in irradiated skin, as compared with nonirradiated skin. Collagenase and gelatinase activity remained maximally elevated (4.4 and 2.3 times, respectively) for seven days with four exposures to ultraviolet irradiation, delivered at two-day intervals, as compared with base-line levels. Multiple exposures to ultraviolet irradiation lead to sustained elevations of matrix metalloproteinases that degrade skin collagen and may contribute to photoaging. Treatment with topical Tretinoin inhibits irradiation-induced proteinases but not their endogenous inhibitor.
The third large factor is nutrition; bad food choices over a lifetime can accelerate skin aging and add a variety of disease conditions that spoil skin appearance. The fourth factor is infection. Skin is the largest tissue area that is normally host to a dense population of microorganisms. A symbiotic relationship exists with most microorganisms as long the skin maintains its surface defenses without interruption. Any breach of surface defenses allows microorganisms to invade and proliferate in the deeper layers of the skin or pass through the skin and invade the body. The most common skin disorders involve infection with bacteria, fungi and viruses. Chronic infection will cause skin deformity in the form of inflammation, scarring pigmentation and accelerated aging.
Retinoids Vitamin A analogues have many effects on skin growth and some have been used to reduce wrinkling. Retin-A was the first popular agent intended for acne treatment but widely sought as a cosmetic agent. The alpha hydroxy acids came next - these are acids common in many plants that peel the surface layers of the skin. Vitamin C, collagen, beta hydroxy acids, vitamin E, elastin and liposome have appeared in numerous skin products with claims that are not readily substantiated. The net effect of most surface treatment with agents of any type is that little or nothing changes. The rejuvenating cream has not yet been discovered. Vitamin C and E have great promise for long-term antiaging effects but they are best taken orally rather than applied to the surface, although there is room for both to be added to sunscreen lotions to reduce photo-damage
Estrogen deficiency is a skin-aging factor in peri- and post-menopausal women. Estrogen treatment with estradiol and the estriol for 6 months improved elasticity and firmness of the skin and the wrinkle depth and pore sizes had decreased up to 100%. Skin moisture increased along with significant increases in the numbers of collagen fibers at the end of the treatment period.