Acute Effects of Fractional Laser on Photo-Aged Skin.

Background Nonablative fractional photothermolysis ( FP) laser treatment has shown clinical efficacy on photo-aged skin. Few studies have examined the molecular responses to FP. Objective To characterize the dynamic alterations involved in dermal matrix remodeling after FP laser treatment. Methods A single multipass FP treatment was performed. Baseline, day 1, and day 7 biopsies were obtained. Biopsies were sectioned and stained for histology and immunofluorescence confocal microscopic. Heat shock protein-70 ( HSP-70) and matrix metalloproteinase-1 ( MMP-1) expression and extracellular matrix ( ECM) autofluorescence were examined. Quantitative real-time polymerase chain reaction ( qRT- PCR) experiments were performed probing for collagen 1A1 ( COL1A1) and COL3A1. Results All three patients were Caucasian women aged 49, 62, and 64 with Fitzpatrick skin types II, III, and IV. Transient neutrophilic infiltration found on day 1. Protein expression of HSP-70 and MMP-1 were up-regulated on day 1, reverting to baseline by day 7. ECM autofluorescence decreased from baseline to day 7. qRT- PCR showed a minor decrease in COL1A1 and COL3A1 messenger RNA 1 day after treatment. Variable results between patients receiving equal treatment were evident. [ABSTRACT FROM AUTHOR]