Folato Natural na Pele Humana
publicado em 09/04/2020
Steven W. Bailey e June E. Ayling
University of South Alabama, Mobile, AL, EUA
O folato natural predominante na pele, o 5-MTHF, é intrinsecamente estável sob UV, mas pode degradar se os fotosensibilizadores estiverem presentes. O 5-MTHF submicromolar protege o DNA contra a oxidação, e os níveis de ascorbato presentes na pele ajudam a manter o folato nela. Níveis de folato diminuídos influenciam a taxa de dano do DNA. Este artigo explora como o reforço de folatos antes da exposição à UV pode proteger a pele contra danos ao DNA.
The predominant natural folate in skin, 5-MTHF, is intrinsically stable under UV but can degrade if photosensitizers are present. Sub-micromolar 5-MTHF protects DNA against oxidation, and ascorbate levels in skin help maintain this folate. Diminished folate levels impact the rate of DNA damage, thus this article explores how reinforcing skin folates prior to UV exposure could protect against DNA damage.
El folato natural predominante en la piel, 5-MTHF, es intrínsecamente estable bajo la radiación ultravioleta, pero puede degradarse si los fotosensibilizadores están presentes. El 5-MTHF submicromolar protege el ADN contra la oxidación y los niveles de ascorbato en la piel ayudan a mantener este ácido fólico. La disminución de los niveles de folato afecta la tasa de daño en el ADN, por lo que este artículo explora cómo reforzar los folatos, antes de la exposición a los rayos UV, podría proteger la piel contra el daño del ADN.
Estabilidade do Folato UV e à Fotossensibilização
Efeito do Folato no Dano ao DNA induzido por UV
Mecanismo de 5-MTHF com Fotossensibilizante
Degradação do Folato da Pele por UV
O risco de desenvolver câncer de pele está fortemente relacionado com a exposição ao Sol.1 Tanto a radiação UVB quanto a UVA, a qual penetra mais profundamente na pele, são componentes da radiação solar que estimulam a progressão do melanoma.2 Além disso, as lâmpadas usadas nas modernas câmaras de bronzeamento, que usam predominantemente UVA, às vezes são mais intensas do que a luz solar natural. Na verdade, o carcinoma de célula basal e de célula escamosa, e o melanoma já foram associados ao uso de câmaras de bronzeamento.3-7
Vários mecanismos inerentes à pele ajudam a mitigar as lesões causadas a ela pela radiação UV. O primeiro deles é o bloqueio físico realizado pela pigmentação. É sabido que pessoas com pele mais escura estão sob risco muito menor de formação de câncer de pele do que indivíduos de pele mais clara. No entanto, a penetração de UVB nas camadas basais da epiderme é necessária para que ocorra a fotoconversão do 7-de-hidrocolesterol em pró-vitamina D3. Uma hipótese defende a tese de que a necessidade da produção adequada de vitamina D tenha levado à mudança de pele mais escura para pele mais clara em populações que migraram da África para locais que ficam em latitudes mais ao norte, onde a exposição anual à UV é menos intensa.20 Por outro lado, as pessoas com menos melanina que migraram para latitudes mais próximas a linha do equador, por exemplo, norte da Austrália, passaram a apresentar taxas muito mais elevadas de câncer de pele.
Além da pigmentação, os mecanismos de reparo do DNA formam outra classe de proteção inerente que visa prevenir danos permanentes causados pela radiação. Lesões ao DNA podem ser induzidas por UVA em culturas de células e na pele
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