Intraepidermal erbium:YAG laser resurfacing: Impact on the dermal matrix

Abstract

Various minimally invasive treatments enhance the skin's appearance. Little is known about the molecular mechanisms whereby treatments working at the epidermal level might alter the dermis. We sought to quantify the molecular changes that result from erbium:yttrium-aluminium-garnet (Er:YAG) laser microablative resurfacing. We performed biochemical analyses after intraepidermal Er:YAG laser resurfacing of 10 patients. Immunohistochemical analysis and polymerase chain reaction technology were utilized to measure key biomarkers. The basement membrane remained intact after intraepidermal microablation, as demonstrated by laminin γ2 immunostaining. Epidermal injury was demonstrated with acute up-regulation of keratin 16. An inflammatory response ensued as indicated by increases in cytokines interleukin 1 beta (IL-1β) and IL-8 as well as a substantial neutrophil infiltrate. Levels of cJun and JunB proteins, components of the transcription factor AP-1 complex, were also elevated. Up-regulation of extracellular matrix degrading proteinases matrix metalloproteinase 1 (MMP-1), MMP-3, and MMP-9 was noted. Atransient increase in keratinocyte proliferation, as indicated by staining for Ki67, was observed. Increased expression of type I and type III procollagen was demonstrated. The data presented are those that resulted from a single treatment session. Although microablation was confined to the uppermost epidermis, marked changes in epidermal and dermal structure and function were demonstrated after Er:YAG laser microablative resurfacing. We demonstrated substantial dermal matrix remodeling, including a degree of collagen production that compares favorably with some more invasive interventions. Dermal remodeling and stimulation of collagen production are associated with wrinkle reduction. Thus these results suggest that the skin's appearance may be enhanced by creating dermal changes through the use of superficially acting treatments.