106: Skin Aging Flashcards
What is the role of oxidative damage in the aging process of the skin?
Oxidative damage leads to the upregulation of stress-related factors, triggering downstream events that enable the aging process. This includes the activation of hypoxia-inducible factors and nuclear factor kB, which promote the expression of pro-inflammatory cytokines such as IL-1, IL-6, VEGF, and TNF-alpha.
What are the intrinsic factors that contribute to skin aging?
Intrinsic skin aging refers to the unavoidable physiological changes influenced by genetic and hormonal factors. Key changes include decreased collagen production, reduced blood flow, lowered amounts of lipids, and loss of rete ridges.
How does extrinsic aging differ from intrinsic aging of the skin?
Extrinsic aging is caused by environmental factors, primarily UV radiation, leading to physiological and histological changes in the skin. Intrinsic aging is due to genetics and hormones.
What are the typical features of photoaging caused by UV radiation?
Photoaging results in deep wrinkles, skin laxity, coarseness, increased fragility, multiple telangiectases, and darker skin with mottled pigmentation.
What is the significance of telomere modification in the context of oxidative stress and aging?
Oxidative stress modifies telomeres, leading to cellular senescence or apoptosis when they reach a critically short threshold.
What is the effect of oxidative damage on cellular proteins?
It leads to the accumulation of damaged proteins that interfere with normal cellular function.
What is intrinsic skin aging?
It refers to the unavoidable physiologic changes of the skin influenced by genetic and hormonal factors.
What are some changes associated with intrinsic skin aging?
Decreased collagen production, reduced blood flow, lowered amounts of lipids, and loss of rete ridges.
What is the most powerful source of extrinsic aging?
UV radiation.
What is photoaging?
UV radiation-mediated structural and functional changes of the skin.
What are some exogenous factors contributing to extrinsic skin aging?
Cigarette smoking, diet, chemical exposure, trauma, and air pollutants.
How does extrinsic skin aging differ from intrinsic skin aging in terms of intervention?
Extrinsic skin aging is more amenable to intervention and preventive measures.
Why is extrinsic skin aging considered more amenable to intervention compared to intrinsic aging?
Extrinsic skin aging is primarily caused by environmental factors, which can be modified through preventive measures.
A 65-year-old patient presents with dry, pale skin and fine wrinkles. What intrinsic factors contribute to these changes?
Intrinsic skin aging is influenced by genetic and hormonal factors, leading to decreased collagen production, reduced blood flow, lowered lipid amounts, and loss of rete ridges.
What percentage of UV radiation that reaches the earth’s surface is UVA and what is its significance in skin aging?
More than 95% of UV radiation that reaches the earth’s surface is UVA, which penetrates to the lower dermis and is considered a larger contributor to skin aging.
What are the effects of UVB radiation on the skin?
UVB radiation only penetrates into the epidermis and upper dermis, serving as a chief source of direct DNA damage, inflammation, and immunosuppression.
How does UV damage affect collagen in the skin?
UV damage impacts collagen degradation and synthesis, leading to the production of elastotic material in the skin.
What is the relationship between photo-damaged skin and mitochondrial DNA mutations?
Photo-damaged skin is associated with a higher frequency of mitochondrial DNA mutations that result in decreased mitochondrial function and generation of reactive oxygen species (ROS).
What changes occur in the epidermis between the third and eighth decades of life?
The epidermal turnover rate decreases by 30-50%, coinciding with deterioration of wound repair capacity and overall thinning of unexposed epidermis by 10-50%.
What is the most pronounced histologic change observed in aged skin?
The most pronounced and consistent histologic change of aged skin is the flattening of the dermal-epidermal junction (DEJ) and loss of rete ridges.
How does estrogen affect skin aging post-menopause?
After menopause, levels of estradiol drop, leading to rapid onset of skin aging characterized by decreased collagen content, thinner skin, reduced elasticity, dryness, and increased wrinkling.
What impact does aging have on the permeability of the stratum corneum?
Aged skin has altered drug permeability with reduced absorption of hydrophilic substances, and there is an impaired barrier partly due to a decline in stratum corneum lipids.
What percentage of UV radiation that reaches the Earth’s surface is UVA?
More than 95%.
What is the primary effect of UVB radiation on the skin?
It is a chief source of direct DNA damage, inflammation, and immunosuppression.