Early destructive effect of sunlight on human skin.
TL;DR: The facial skin of white persons has been assessed throughout the human life span for the severity of elasticfiber changes as an indicator of sunlight damage, and sunlight, not innate aging, is mainly responsible for the worst manifestation of senile skin.
Abstract: The facial skin of white persons has been assessed throughout the human life span for the severity of elasticfiber changes as an indicator of sunlight damage. Elastic hyperplasia began as early as the first decade and was clearly evident in a majority of young adults before the age of 30. Beyond the fourth decade most persons had serious elastic-tissue abnormalities culminating in massive degeneration. The elastotic changes were quite advanced before the extensiveness of the damage became visible clinically. The unexposed skin of the buttock exhibited only a slight increase in elastic fibers in old age. The degree of elastic-tissue damage in different regions of the face was in relation to the amount of sunlight these received, greatest on the ear rim and cheek, least under the chin and eyebrows. Sunlight, not innate aging, is mainly responsible for the worst manifestation of senile skin.
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TL;DR: Drusen associated with aging and age‐related macular degeneration contain proteins common to extracellular deposits associated with atherosclerosis, elastosis, amyloidosis, and dense deposit disease.
Abstract: Age-related macular degeneration (AMD), a blinding disorder that compromises central vision, is characterized by the accumulation of extracellular deposits, termed drusen, between the retinal pigmented epithelium and the choroid. Recent studies in this laboratory revealed that vitronectin is a major component of drusen. Because vitronectin is also a constituent of abnormal deposits associated with a variety of diseases, drusen from human donor eyes were examined for compositional similarities with other extracellular disease deposits. Thirty-four antibodies to 29 different proteins or protein complexes were tested for immunoreactivity with hard and soft drusen phenotypes. These analyses provide a partial profile of the molecular composition of drusen. Serum amyloid P component, apolipoprotein E, immunoglobulin light chains, Factor X, and complement proteins (C5 and C5b-9 complex) were identified in all drusen phenotypes. Transcripts encoding some of these molecules were also found to be synthesized by the retina, retinal pigmented epithelium, and/or choroid. The compositional similarity between drusen and other disease deposits may be significant in view of the recently established correlation between AMD and atherosclerosis. This study suggests that similar pathways may be involved in the etiologies of AMD and other age-related diseases.
911 citations
Cites background from "Early destructive effect of sunligh..."
...Whereas sun-exposed skin typically develops elastotic lesions by the second decade of life, these accumulations are less common and severe in sun-protected areas of the skin (62)....
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TL;DR: It was concluded that topical tretinoin is capable of at least partly reversing the structural damages of excessive sunlight exposure and may be useful in decelerating the photoaging process.
Abstract: Daily topical application of 0.05% tretinoin in a cream base was compared with its vehicle with regard to moderation of photoaging changes of the face and forearms. In comparison with the control tissue, tretinoin-treated tissue examined by light and electron microscopy showed the following effects: replacement of the atrophic epidermis by hyperplasia, elimination of dysplasia and atypia, eradication of microscopic actinic keratoses, uniform dispersion of melanin granules, new collagen formation in the papillary dermis, new vessel formation (angiogenesis), and exfoliation of retained horn in the follicles. Physiologic studies demonstrated: increased blood flow and dermal clearance, increased transepidermal water loss, and greater permeability and reactivity. It was concluded that topical tretinoin is capable of at least partly reversing the structural damages of excessive sunlight exposure and may be useful in decelerating the photoaging process.
569 citations
TL;DR: It is indicated that naturally aged, sun-protected skin and photoaged skin share important molecular features including connective tissue damage, elevated matrix metalloproteinase levels, and reduced collagen production.
543 citations
TL;DR: A definition of the skin aging exposome is proposed, based on a summary of the existing scientific evidence for the role of exposomes factors in skin aging and future research needs which concern knowledge about the interaction of distinct exposomal factors with each other and the resulting net effects on skin aging are identified.
431 citations
Cites background from "Early destructive effect of sunligh..."
...Albert Kligman first suggested in 1969 that apart from intrinsic aging factors, sun exposure causes skin damage and aging [9]....
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TL;DR: The objective is to review present state-of-the-art knowledge pertaining to mechanisms involved in skin aging, with specific focus on the dermal collagen matrix.
Abstract: Skin appearance is a primary indicator of age. During the last decade, substantial progress has been made toward understanding underlying mechanisms of human skin aging. This understanding provides the basis for current use and new development of antiaging treatments. Our objective is to review present state-of-the-art knowledge pertaining to mechanisms involved in skin aging, with specific focus on the dermal collagen matrix. A major feature of aged skin is fragmentation of the dermal collagen matrix. Fragmentation results from actions of specific enzymes (matrix metalloproteinases) and impairs the structural integrity of the dermis. Fibroblasts that produce and organize the collagen matrix cannot attach to fragmented collagen. Loss of attachment prevents fibroblasts from receiving mechanical information from their support, and they collapse. Stretch is critical for normal balanced production of collagen and collagen-degrading enzymes. In aged skin, collapsed fibroblasts produce low levels of collagen and high levels of collagen-degrading enzymes. This imbalance advances the aging process in a self-perpetuating, never-ending deleterious cycle. Clinically proven antiaging treatments such as topical retinoic acid, carbon dioxide laser resurfacing, and intradermal injection of cross-linked hyaluronic acid stimulate production of new, undamaged collagen. Attachment of fibroblasts to this new collagen allows stretch, which in turn balances collagen production and degradation and thereby slows the aging process. Collagen fragmentation is responsible for loss of structural integrity and impairment of fibroblast function in aged human skin. Treatments that stimulate production of new, nonfragmented collagen should provide substantial improvement to the appearance and health of aged skin.
413 citations
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TL;DR: Aged unexposed human skin has decreased hexosamine, decreased solubility of dermal collagen, and increased hydroxyproline, but the identity of the histopathologic changes in chronically sun-damaged skin (actinic elastosis) has been debated for many years.
274 citations
261 citations
TL;DR: There is now considerable evidence that sunlight is responsible for most of the visible degenerative changes that occur with the passage of time.
Abstract: AGING IS an interesting subject which is receiving increasing attention in many fields. There is an ever-enlarging body of information which indicates that many of the phenomena which were previously regarded as "natural" processes resulting from old age are actually due to specific disease processes. The changes occurring with arteriosclerosis are prime examples. Factors contributing to aging and premature aging of the skin have not received adequate attention. There is now considerable evidence that sunlight is responsible for most of the visible degenerative changes that occur with the passage of time. The laxity and folding of the skin resulting from weight loss should not be confused with aging of the skin, although these occur most frequently in elderly, debilitated people. In Simmond's disease and in Werner's and related syndromes, patients may appear to be prematurely aged and the skin is found to be atrophie; but few studies of the skin
40 citations
01 Jan 1965
TL;DR: Covered aged skin shows marked differences histochemically and biochemically from exposed aged skin, and with aging there is a decrease of non fibrous protein and of soluble collagen, although the total collagen increases.
Abstract: Synopsis--The changes in human Caucasian skin commonly believed to be due to aging are primarily the effects of prolonged repeated damage to the skin from the sun. Covered aged skin shows marked differences histochemically and biochemically from exposed aged skin. With aging there is a decrease of non fibrous protein and of soluble collagen, although the total collagen increases. The total aci• mucopolysaccharides decrease, especially hyaluronic acid. In chronically sun-damaged skin (actinic elastosis) there is little change in the amount of extractable soluble collagen. The insoluble collagen content is reduced to one-third of that of control skin, and there is an increase in an elastin-like protein. Total acid mucopolysaccharides increase in actinic elastosis, especially hyaluronic acid.
14 citations