The UV/Visible Radiation Boundary Region (385–405 nm) Damages Skin Cells and Induces “dark” Cyclobutane Pyrimidine Dimers in Human Skin in vivo

Abstract

The adverse effects of terrestrial solar ultraviolet radiation (UVR) (~295–400 nm) on the skin are well documented, especially in the UVB region (~295–320 nm). The effects of very long-wave UVA (>380 nm) and visible radiation (≥400 nm) are much less known. Sunscreens have been beneficial in inhibiting a wide range of photodamage, however most formulations provide very little protection in the long wave UVA region (380–400 nm) and almost none from shortwave visible wavelengths (400–420 nm). We demonstrate photodamage in this region for a number of different endpoints including cell viability, DNA damage (delayed cyclobutane pyrimidine dimers), differential gene expression (for genes associated with inflammation, oxidative stress and photoageing) and induction of oxidizing species in vitro in HaCaT keratinocytes and in vivo in human volunteers. This work has implications for phototherapy and photoprotection.

Acetyl zingerone: An efficacious multifunctional ingredient for continued protection against ongoing DNA damage in melanocytes after sun exposure ends

“…A recent study in melanocytes [6] documented that CPDs continued to increase by 50% or more after irradiation ended, in the dark and independent of additional UVR photons. More recently, CPD formation in the dark (now referred to as dark-CPDs) was also reported to occur in keratinocytes not only in vitro but also in vivo in human skin at measurable levels within the first 2 h after exposure to UVA/visible radiation [7,8].…”

High‐energy visible light at ambient doses and intensities induces oxidative stress of skin—Protective effects of the antioxidant and Nrf2 inducer Licochalcone A in vitro and in vivo

“…In contrast to dermatology, the clinical relevance of high‐energy visible light (HEVIS) induced ROS effects on ocular tissues, in particular the retina, has been acknowledged much earlier, prompting questions regarding potentially harmful effects on sun‐exposed skin . Recently, UV/VIS (385‐405 nm) was reported to induce delayed CPD formation in vivo . In contrast to other wavelengths of VIS, HEVIS exposure leads to a significant decrease in viability of different skin cell lines and more pronounced shrinkage of the extracellular matrix (ECM) .…”

“…11,12 Recently, UV/VIS (385-405 nm) was reported to induce delayed CPD formation in vivo. 13 In contrast to other wavelengths of VIS, HEVIS exposure leads to a significant decrease in viability of different skin cell lines and more pronounced shrinkage of the extracellular matrix (ECM). [14][15][16] Like UVA, HEVIS appears to exert its effects mainly through the generation of ROS, accounting for a substantial part of the amount generated by natural midday sunlight in human skin.…”

Shining light on darker skins

“…One possible consequence of this is increased exposure to solar visible and infrared radiation. There is increasing evidence that these spectral regions have adverse effects on skin, especially photoageing …”