Biological effect of laser-assisted scar healing (LASH) on standardized human three-dimensional wound healing skin models using fractional non-ablative 1540 nm Er:Glass or 1550 nm diode lasers.

PURPOSE: In postoperative wound healing after surgical operations or ablative laser treatments, recent studies suggest the timely use of non-ablative fractional laser treatments with the aim to improve wound healing and prevent pathological scar formation. However, the underlying molecular mechanisms are poorly understood. The aim of this study was to investigate the effects of laser-assisted scar healing (LASH) at the molecular level and to combine it with already established wound healing-promoting local treatments. METHODS: We irradiated full-thickness 3D skin models with a fractional ablative Er:YAG laser to set standardized lesions to the epidermal and upper dermal layer. Subsequently, LASH was induced by irradiating the models with either a fractional non-ablative 1540 nm Er:Glass or 1550 nm diode laser. In addition, we tested the combination of non-ablative fractional laser treatment and topical aftercare with a dexpanthenol-containing ointment (DCO). RESULTS: Histological analysis revealed that models irradiated with the 1540 nm Er:Glass or 1550 nm diode laser exhibited accelerated but not complete wound closure after 16 h. In contrast, additional topical posttreatment with DCO resulted in complete wound closure. At gene expression level, both non-ablative laser systems showed similar effects on epidermal differentiation and mild anti-inflammatory properties. The additional posttreatment with DCO enhanced the wound-healing effects of LASH, especially the upregulation of epidermal differentiation markers and anti-inflammatory cytokines at the gene expression level. CONCLUSION: This in vitro study deciphers the biological effects of LASH with a fractional non-ablative 1540 nm Er:Glass or a 1550 nm diode laser in 3D skin models. These data help to better understand the biological properties of the LASH technique and is important to optimize its application.

Therapy of pathological scars.

A scar develops following the appearance of a deep tissue defect as part of the physiological wound healing process. The initial inflammatory response is followed by proliferation of connective tissue cells, which form fibrosis as a final tissue substitute. Disorders can occur at all stages of the process and are most commonly manifested as impaired wound healing or the formation of atrophic and hypertrophic scars or keloids. The focus of this article is on the treatment of pathologic scars, which are an indication for therapy due to functional limitations, complaints, and stigmatization, among other reasons. Conservative medical, physical, surgical and laser therapeutic approaches are pursued. The basis for this is an understanding of the pathophysiological mechanisms and factors influencing the choice of therapy, as well as an interdisciplinary and interprofessional therapeutic approach.