Fractional Laser Resurfacing Treats Photoaging by Promoting Neocollegenesis and Cutaneous Edema

BACKGROUND: Laser resurfacing is a common treatment for photoaging. This treatment creates skin incisions that initiate the wound healing cascade, including reorganization of the collagen matrix, in a dermal remodeling process that can last up to 12 months. OBJECTIVE: We compared the effects of nonablative and ablative Erbium fractional laser resurfacing on dermal content and arrangement of Collagen Types I and III, and on fibroblast activation. METHODS: Ten female patients (50-63 years) with Fitzpatrick Skin Types I-IV and clinical signs of photoaging underwent two types of Erbium fractional laser resurfacing (nonablative, 1540nm; ablative, 2940nm) on opposite sides of the face. Skin biopsies were obtained pretreatment and three months post-treatment. Morphometric analysis was performed using Picrosirius staining for overall collagen, and immunohistochemistry for Collagen Types I and III. Finally, hematoxylin and eosin staining was used to identify fibroblast activation. RESULTS: Both laser treatments induced reorganization of Collagen Types I and III and demonstrated signs of fibroblast activation. However, morphometric analysis of Picrosirius staining revealed that, after both treatments, there was a lower density of collagen fibers, which is characteristic of edema. CONCLUSION: At three months after laser resurfacing, skin lifting in photoaged skin likely resulted from new collagen deposition but also from edema.