“As dermatologists, we all have patients who are quite diligent in terms of sun protection, especially folks who have had skin cancers,” Dr. Chien says. But despite their efforts, sometimes these patients may present with a tan or sunburn. To date, most attention has targeted ultraviolet (UV) light, particularly UVB. In addition to UVB, the CTReP is exploring the impact of visible light (VL) on the skin.
“Actually, 40% of the radiation that reaches our Earth atmosphere consists of visible light. But there are no products out there that effectively protect against visible light,” Dr. Chien says. The center recruited volunteers to undergo localized VL irradiation of the lower back.
“Then we tracked the patients over time, checking for pigmentation, redness and blistering,” Dr. Chien says.
VL induced hyperpigmentation in dark skin but not light skin, she says. At 24 hours post-treatment, genes involved in oxidation, immune response and pigmentation were upregulated in VL-exposed skin. One week post-treatment, VL-induced pigmentation that occurred in dark skin correlated with increases in chemokine (C-C motif) ligand 18 (CCL18) and tyrosinase gene expression.1
The CTReP also has investigated whether oral or topical broccoli sprout extract can protect against sun-induced erythema and in ammation. These studies aim to provide additional and possibly more effective photoprotection methods for patients.
Dr. Chien reports no relevant fi nancial interests. The CTReP has received grants from Galderma, Johnson & Johnson, L’Oreal, Kyocera, Lutronic, Mela Sciences, Pfizer, SkinMedica, Unilever and Walgreens Boots Alliance.
1. Rainer B, Qi J, Martin J, et al. Visible light-induced hyperpigmentation in human skin in vivo occurs in dark, but not in light skin, and is associated with differential induction of CCL18 and tyrosinase genes. Society for Investigative Dermatology Annual Meeting. May 6-9, 2015. Atlanta.
2. Sheu M. Biomarkers activated with fractionated laser. Photomedicine Society Annual Meeting. February 28, 2019. Washington, D.C.
3. OkoyeGA,Rainer BM,Leung SG, et al. Improvingacnekeloidalis nuchae with targeted ultraviolet B treatment: a prospective, randomized, split-scalp comparison study. Br J Dermatol.2014;171(5):1156-63.