Alteration of extracellular matrix modulators after nonablative laser therapy in skin rejuvenation

Background: Nonablative laser therapy is widely practised for skin rejuvenation, which stimulates collagen production and dermal matrix remodelling. Matrix remodelling is primarily modulated by a coordinated action of matrix metalloproteinases (MMPs) and their inhibitors, but the effects of nonablative lasers on these matrix modulators are not fully investigated. Objectives: To evaluate the changes in matrix modulators, such as MMP-1, MMP-2, MMP-3, MMP-9 and MT1-MMP, and their inhibitors (TIMP-1, TIMP-2 and RECK in particular), after nonablative laser treatments of human facial skin. Methods: Twenty-four adult volunteers received a series of four nonablative laser treatments separated by 3-week intervals on facial skin. Two-millimetre skin punch biopsies were obtained at baseline and 3 weeks after the last treatment. Results: Nonablative laser treatments led to a robust increase in two major dermal matrix components, type I collagen and tropoelastin. Among MMPs tested, levels of MMP-2 mRNA were statistically significantly increased, but the amount of active MMP-2 was rather reduced. More importantly, the expression level of RECK was significantly enhanced by laser treatments. Conclusions: Clinical outcomes following nonablative laser treatments may result not only from increased biosynthesis but also from decreased degradation, via an induction of RECK expression, of matrix proteins.