2016 Arte Poster Competition First Place Winner: Circadian Rhythm and UV-Induced Skin Damage: An In Vivo Study.

Exposure of the skin to ultraviolet (UV) irradiation causes many detrimental effects through mechanisms related to oxidative stress and DNA damage. Excessive oxidative stress can cause apoptosis and cellular dysfunction of epidermal cells leading to cellular senescence and connective tissue degradation. Direct and indirect damage to DNA predisposes the skin to cancer formation. Chronic UV exposure also leads to skin aging manifested as wrinkling, loss of skin tone, and decreased resilience. Fortunately, human skin has several natural mechanisms for combating UV-induced damage. The mechanisms operate on a diurnal rhythm, a cycle that repeats approximately every 24 hours. It is known that the circadian rhythm is involved in many skin physiologic processes, including water regulation and epidermal stem cell function. This study evaluated whether UV damage and the skin's natural mechanisms of inflammation and repair are also affected by circadian rhythm. We looked at UV-induced erythema on seven human subjects irradiated with simulated solar radiation in the morning (at 08:00 h) versus in the afternoon (at 16:00 h). Our data suggest that the same dose of UV radiation induces significantly more inflammation in the morning than in the afternoon. Changes in protein expression relevant to DNA damage, such as xeroderma pigmentosum, complementation group A (XPA), and cyclobutane pyrimidine dimers (CPD) from skin biopsies correlated with our clinical results. Both XPA and CPD levels were higher after the morning UV exposure compared with the afternoon exposure.

J Drugs Dermatol. 2016;15(9):1124-1130.

Concomitant mycosis fungoides and vitiligo: how mycosis fungoides may contribute to melanocyte destruction.

BACKGROUND: Few reports have described vitiligo developing in patients with cutaneous T-cell lymphoma (CTCL). OBJECTIVE: We sought to identify possible factors that might predispose patients with CTCL to vitiligo. METHODS: Patient demographics, CTCL disease characteristics and treatments were analyzed in 25 patients with CTCL who developed vitiligo. Cox proportional hazards modeling was used to identify associations of risk factors with the development of vitiligo. RESULTS: Younger age, later CTCL disease stage (stages IIB-IV) and presence of a CD8+CD4- mycosis fungoides phenotype were associated with the development of vitiligo. After adjusting for disease stage, increased risk of vitiligo was associated with methotrexate and CD4 antibody therapies (although the total number of patients with these was small), while decreased risk was associated with nitrogen mustard and PUVA therapies. CONCLUSIONS: No single feature was common to all of our patients, suggesting that multiple factors may contribute to the development of vitiligo in a patient-specific fashion.