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 triggers the aging process according to oxidative stress theory?
Oxidative damage leads to the upregulation of stress-related factors, triggering downstream events.
What are some cytokines expressed due to oxidative stress?
IL-1, IL-6, VEGF, TNF-alpha.
What is the effect of oxidative damage on cellular proteins?
It leads to the accumulation of damaged proteins that interfere with normal cellular function.
How does oxidative stress affect telomeres?
It modifies telomeres, leading to cellular senescence or apoptosis when they reach a critically short threshold.
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 are the typical features of extrinsic skin aging?
Deep wrinkles, laxity, coarseness, increased fragility, multiple telangiectases, and darker skin with mottled pigmentation.
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.
What role do oxidative stress and hypoxia-inducible factors play in the aging process of the skin?
Oxidative stress leads to the upregulation of stress-related factors, triggering downstream events that enable the aging process.
What are the intrinsic factors contributing to skin aging, and what are the observable changes in the skin?
Intrinsic skin aging is influenced by genetic and hormonal factors, leading to decreased collagen production, reduced blood flow, and loss of lipids.
What are the primary environmental factors that contribute to extrinsic skin aging, and what are its typical features?
The primary environmental factor is UV radiation, which causes photoaging. Typical features include deep wrinkles, laxity, coarseness, increased fragility, multiple telangiectases, and darker skin with mottled pigmentation.
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.
How does UV damage affect collagen in the skin?
It impacts collagen degradation and synthesis.
What is associated with a higher frequency of mitochondrial DNA mutations in photo-damaged skin?
Decreased mitochondrial function and generation of ROS.
What happens to the basement membrane following UV radiation exposure?
It becomes multilayered and partially disrupted.
What is the role of estrogen receptor signaling in skin aging?
It is a critical modulator of redox balance and oxidative stress.
What skin changes occur after menopause due to decreased estrogen levels?
Decreased collagen content, thinner skin, reduced elasticity, dryness, and increased wrinkling.
What happens to the epidermal turnover rate between the third and eighth decades of life?
It decreases by 30-50%.
What is the most pronounced histologic change in aged skin?
Flattening of the DEJ and loss of rete ridges.
How does aged skin’s stratum corneum change with age?
It has greater susceptibility to irritant contact dermatitis and severe xerosis.
What happens to drug permeability in aged skin?
There is altered drug permeability with reduced absorption of hydrophilic substances.
What decline contributes to impaired barrier function in intrinsically aged skin?
Decline of stratum corneum lipids.
What age-related change occurs in epidermal filaggrin levels?
There is a decrease in epidermal filaggrin.
What are the primary differences in the effects of UVA and UVB radiation on skin aging?
UVA penetrates to the lower dermis and is a larger contributor to skin aging, while UVB primarily causes direct DNA damage, inflammation, and immunosuppression.
How does UV radiation exposure affect collagen in the skin?
UV damage impacts collagen degradation and synthesis, leading to a higher frequency of mitochondrial DNA mutations.
What changes occur in the skin after menopause due to decreased estrogen levels?
Post-menopausal changes include decreased collagen content, thinner skin, reduced elasticity, dryness, and increased wrinkling.
What histological changes are observed in the epidermis as individuals age?
The most pronounced change is the flattening of the dermal-epidermal junction (DEJ) and loss of rete ridges.
How does the epidermal turnover rate change with age, and what are the implications for wound repair?
Between the third and eighth decades of life, the epidermal turnover rate decreases by 30-50%, coinciding with a deterioration of wound repair capacity.
What impact does aging have on the permeability of the stratum corneum?
Aged skin has altered drug permeability with reduced absorption of hydrophilic substances.
A postmenopausal woman complains of rapid skin aging. What hormonal changes are likely responsible?
Postmenopausal skin aging is associated with decreased estradiol levels.
A patient with photodamaged skin has a multilayered and partially disrupted basement membrane. What is the likely cause?
The likely cause is UV radiation exposure.
A patient with photodamaged skin has increased ROS generation. What is the impact of visible light on this process?
Visible light generates ROS in the skin, leading to the formation of oxidized DNA bases and increased pro-inflammatory cytokines.
What are the cellular changes associated with increased dryness and scaliness of older skin?
Cellular heterogeneity leading to epidermal dyscrasia characterized by reduced mitotic activity, lengthened cell cycle, and increased migration time.
How does aging affect collagen in the dermis?
Aging leads to biochemical changes in collagen resulting in increased rigidity and impaired wound healing.
What is solar elastosis and how does it relate to aging skin?
Solar elastosis is characterized by replacement of normal elastic fibers with a disordered mass of elastotic material, reflecting the impact of chronic sun exposure.
What changes occur in the ground substance of the skin with aging?
With aging, the ground substance is affected, leading to decreased interaction of protein and water.
What cellular changes contribute to increased dryness and scaliness of older skin?
Cellular heterogeneity results in epidermal dyscrasia, reduced mitotic activity, and increased migration time.
How does the density of melanocytes change in photodamaged skin with age?
Melanocytes double in density, but functional melanocyte numbers decline by up to 20% per decade.
What is the relationship between melanocyte decline and skin cancer risk in the elderly?
The decrease of melanocytes is associated with a decrease in protective melanin, leading to an elevated risk of skin cancer.
What happens to the incidence of melanocytic nevi with age?
The incidence of melanocytic nevi declines with age.
What age-related changes occur in the dermis regarding collagen?
There is increased rigidity and impaired wound healing due to a reduction of collagen types I and III.
How does aging affect the collagen-synthetic capacity of fibroblasts?
There is an age-dependent difference in the collagen-synthetic capacity of aging fibroblasts.
What is the effect of elevated MMP activity in chronically photodamaged skin?
Elevated MMP activity creates a microenvironment of fragmented collagen.
How does aging affect the collagen-synthetic capacity of fibroblasts?
There is an age-dependent difference in the collagen-synthetic capacity of aging fibroblasts, leading to lower collagen synthesis in intrinsically aged skin.
What is the effect of elevated MMP activity in chronically photodamaged skin?
Elevated MMP activity creates a microenvironment of fragmented collagen, impairing fibroblast function and leading to abnormal collagen homeostasis.