Dietary green tea catechins protect dermal elasic fibers from UV-induced remodeling

Cutaneous photoaging is associated with dermal elastic fiber remodeling; daily photoprotection is therefore essential to prevent ultraviolet (UV)‐induced skin damage. Green tea (C sinensis), rich in polyphenol catechins (GTC), have been reported to have significant skin benefits in vitro and in vivo. We have performed a double‐blind randomised controlled trial to assess whether systemic GTC supplementation can protect dermal elastic fibers from acute UV exposure. Healthy white Caucasians (n=50; 18‐65 years) were randomized (1:1) to 12 weeks daily oral supplement (1080mg GTC with 100mg viatmin C) or placebo (maltodextrin). Biopsies were taken from skin exposed to 3xMED of solar simulated radiation (SSR) and unexposed skin at baseline and post‐supplementation; compliance was confirmed by urinary GTC metabolite analysis. Dermal elastic fibers were identified via histology and immunohistochemistry, their distribution assessed in the papillary dermis (from the dermal‐epidermal junction to a depth of 100mum) by image analysis. Differences between UV‐exposed and unexposed skin were analysed by paired t‐test. A total of 44 subjects completed the study, being compliant with supplementation and providing all skin samples. At baseline, SSR induced a significant overall loss of elastic fiber components (P= 0.001), and specifically fibulins‐2 and ‐5. Post‐supplementation, UV‐mediated loss of fibulin‐5 remained significant in the placebo group with mean (SD) % fiber area 19.4 (3.8) and 17.7 (4.1) in unexposed and UV‐exposed skin resectively (P=0.01), whilst in the active group fibulin‐5 was protected with % fiber area 18.1 (4.0) and 17.1 (2.7) in unexposed and UV‐exposed skin respectively (P= 0.30). Hence, acute SSR exposure results in elastic fiber remodeling similar to that observed in chronically photoaged skin. Furthermore, in a randomized control trial, dietary GTC protected fibulin‐5 microfibrils in the papillary dermis from UV‐mediated degradation.