Whitening Effects of Adipose-Derived Stem Cells: A Preliminary In Vivo Study

Many studies have reported various growth factors secreted from adipose-derived stem cells (ADSCs). In particular, regenerative effects in skin have received much attention in the clinical fields. The in vitro whitening effects of ADSCs have been reported. A previous study demonstrated that ADSCs secrete growth factors that inhibit both melanin synthesis and tyrosinase activity. This study aimed to investigate the in vivo whitening effect of ADSCs using mouse models. In the study, ADSCs were isolated from the adipose tissue of C57BL/6 mice and cultured. The ADSCs (1 × 10 6 cells in 30 μl of Hanks’ balanced salt solution [HBSS]) then were injected intradermally in the dorsal area of the right ear, and 30 μl of HBSS was injected on the left ear as a control. After 7 days, both ears were irradiated with ultraviolet B (UVB) (150 mJ/cm 2 ) three times at 2-day intervals. The sections of each ear were stained with hematoxylin-eosin, Fontana–Masson, and HMB-45 (a melanocytic cell-specific monoclonal antibody). The histologic parameters evaluated included inflammation (+/−), erosion (+/−), and melanin formation (graded on a scale of 1 to 3). No significant differences in inflammation or erosion were observed by hematoxylin and eosin staining (inflammation: p = 0.388; erosion: p = 0.355). However, significantly more melanin formation was observed in the control group than in the ADSC injection group by Fontana–Masson and HMB-45 staining (Fontana–Masson: p = 0.025; HMB-45: p = 0.015). The study findings suggest that ADSCs inhibit melanin formation induced by UV exposure. Potentially, ADSCs may be used as anti-aging agents, including skin whitening. Before human clinical studies can be conducted, further study is required to determine the mechanisms underlying the whitening effects of ADSCs and the safety of ADSC use. Level of Evidence II This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .