Photoaging of the skin from phenotype to mechanisms

Introduction to skin aging

“…ROS induces gene expression pathways result in increased degradation of collagen and accumulation of elastin. 123 ROS not only directly destroys interstitial collagen, but also inactivates tissue inhibitors of matrix-metalloproteases and induces the synthesis and activation of matrix degrading metalloproteases. 123 Hormones have also been shown to play a role as post-menopausal hormone changes are responsible for a rapid worsening of skin structure and functions, and these can be at least partially repaired by HRT or local estrogen treatment.…”

“…123 ROS not only directly destroys interstitial collagen, but also inactivates tissue inhibitors of matrix-metalloproteases and induces the synthesis and activation of matrix degrading metalloproteases. 123 Hormones have also been shown to play a role as post-menopausal hormone changes are responsible for a rapid worsening of skin structure and functions, and these can be at least partially repaired by HRT or local estrogen treatment. 113,124 Mitochondrial DNA incurs regular DNA damage due to repeated constitutional oxidative stress, and in particular deletion of a specific length of DNA called common deletion that is 10 times more common in photodamaged than in sun-protected skin.…”

A Definitive Role of Ornithine Decarboxylase in Photocarcinogenesis

“…Oral consumption of ␣-difluoromethylornithine, an irreversible specific inhibitor of ODC, in the drinking water (1% w/v) to the transgenic mice resulted in complete prevention of UVB-mediated tumorigenesis and a substantial decrease in the formation of pigmented cysts Excessive exposure of skin to ultraviolet (UV) light, particularly in the middle wavelength range (UVB; 290 to 320 nm), elicits a variety of adverse effects that include skin aging, cutaneous inflammation, erythema, immunosuppression, cell death, and skin cancer. [1][2][3][4][5][6] More than a million new cases of nonmelanoma skin cancers, which include basal cell carcinoma and squamous cell carcinoma (both derived from epidermal keratinocytes), are diagnosed annually in the United States. 6,7 Unlike chemically induced skin carcinogenesis, UV is a complete carcinogen with both tumor-initiating as well as tumorpromoting effects.…”

Fotoprotetores derivados de produtos naturais: perspectivas de mercado e interações entre o setor produtivo e centros de pesquisa

“…A radiação UVC é absorvida pelo oxigênio e pelo ozônio na estratosfera, enquanto que apesar de representarem uma baixa porcentagem da luz solar que atinge a superfície da Terra, as radiações UVB e UVA são importantes do ponto de vista biológico, pois podem causar diversos efeitos como, por exemplo, o desencadeamento de estresse oxidativo às células. 2 Estas radiações podem ser danosas a várias biomoléculas como, por exemplo DNA, proteínas e lipídeos, causando disfunções estruturais e funcionais. 3 A pele é o órgão mais externo e, consequentemente, a interface entre o corpo e o meio ambiente.…”