Intense pulsed light enhances transforming growth factor beta1/Smad3 signaling in acne-prone skin

Abstract

Recently, much interest has been generated in the use of intense pulsed light (IPL) sources in the treatment of various skin conditions. However, the underlying mechanism for its therapeutic action has not been elucidated. To investigate the effect of IPL on the in vivo expression of transforming growth factor beta1 (TGF-β1) and on the immunolocalization of Smad3 in biopsies obtained from perilesional skin in patients with mild-to-moderate inflammatory acne vulgaris. Biopsies obtained from 20 patients with inflammatory acne vulgaris at baseline (B1) and post-IPL treatment (B2=48h after first treatment and B3=1week after final treatment) were immunohistochemically analyzed to determine the expression of TGF-β1 and the immunolocalization of Smad3. Digital images were semiquantitatively assessed using image analysis software. Intense pulsed light elicited a consistent increase in epidermal TGF-β1 expression (B2 vs. B1: P=0.004 and B3 vs. B1: P=0.007). Furthermore, it resulted in enhanced nuclear immunolocalization of Smad3 (B2 vs. B1: epidermis, P=0.000055 and dermis, P=0.014; B3 vs. B1: epidermis, P=0.00024 and dermis, P=0.008). Intense pulsed light upregulates TGF-β1/Smad3 signaling in perilesional skin obtained from patients with mild-to-moderate inflammatory acne vulgaris. Further experiments on lesional skin and downstream effects are warranted to determine whether it may play a role in IPL-induced resolution of acne vulgaris.