1. Alterations of the pigmentation system in the aging process
- Author
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Mauro Picardo, Barbara Bellei, Federica Papaccio, Jin Wook Lee, and Hee Young Kang
- Subjects
0301 basic medicine ,Senescence ,Photoaging ,Skin Pigmentation ,Human skin ,Dermatology ,Vitiligo ,Environment ,Biology ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,0302 clinical medicine ,Hyperpigmentation ,Stress, Physiological ,medicine ,Animals ,Humans ,Hypopigmentation ,integumentary system ,Dermis ,medicine.disease ,Phenotype ,Intrinsic and extrinsic aging ,Skin Aging ,Cell biology ,030104 developmental biology ,Oncology ,030220 oncology & carcinogenesis ,medicine.symptom ,Homeostasis - Abstract
Human skin aging is a natural phenomenon that results from continuous exposure to intrinsic (time, genetic factors, hormones) as well as extrinsic factors (UV exposure, pollution, tobacco). In areas that are frequently exposed to the sun, photoaging blends with the process of intrinsic aging, resulting in an increased senescent cells number and consequently accelerating the aging process. The severity of photodamage depends on constitutional factors, including skin phototype (skin color, tanning capacity), intensity, and duration of sunlight/UV exposure. Aging affects nearly every aspect of cutaneous biology, including pigmentation. Clinically, the phenotype of age pigmented skin has a mottled, uneven color, primarily due to age spots, with or without hypopigmentation. Uneven pigmentation might be attributed to the hyperactivation of melanocytes, altered distribution of pigment, and turnover. In addition to direct damage to pigment-producing cells, photodamage alters the physiological crosstalk between keratinocytes, fibroblasts, endothelial cells, and melanocytes responsible for natural pigmentation homeostasis. Interestingly, age-independent diffuse expression of senescence-associated markers in the dermal and epidermal compartment is also associated with vitiligo, suggesting that premature senescence plays an important role in the pathology.
- Published
- 2021