title: Molecular effects of fractional ablative erbium:YAG laser treatment with multiple stacked pulses on standardized human three-dimensional organotypic skin models.
abstract: The molecular changes in gene expression following ablative laser treatment of skin lesions, such as atrophic scars and UV-damaged skin, are not completely understood. A standardized in vitro model of human skin, to study the effects of laser treatment on human skin, has been recently developed. Therefore, the aim of the investigation was to examine morphological and molecular changes caused by fractional ablative erbium:YAG laser treatment on an in vitro full-thickness 3D standardized organotypic model of human skin. A fractional ablative erbium:YAG laser was used to irradiate organotypic human 3D models. Laser treatments were performed at four different settings using a variety of stacked pulses with similar cumulative total energy fluence (60 J/cm2). Specimens were harvested at specified time points and real-time PCR (qRT-PCR) and microarray studies were performed. Frozen sections were examined histologically. Three days after erbium:YAG laser treatment, a significantly increased mRNA expression of matrix metalloproteinases and their inhibitors (MMP1, MMP2, MMP3, TIMP1, and TIMP2), chemokines (CXCL1, CXCL2, CXCL5, and CXCL6), and cytokines such as IL6, IL8, and IL24 could be detected. qRT-PCR studies confirmed the enhanced mRNA expression of IL6, IL8, IL24, CXCLs, and MMPs. In contrast, the mRNA expression of epidermal differentiation markers, such as keratin-associated protein 4, filaggrin, filaggrin 2, and loricrin, and antimicrobial peptides (S100A7A, S100A9, and S100A12) as well as CASP14, DSG2, IL18, and IL36β was reduced. Four different settings with similar cumulative doses have been tested (N10%, C10%, E10%, and W25%). These laser treatments resulted in different morphological changes and effects on gene regulations. Longer pulse durations (1000 μs) especially had the strongest impact on gene expression and resulted in an upregulation of genes, such as collagen-1A2, collagen-5A2, and collagen-6A2, as well as FGF2. Histologically, all treatment settings resulted in a complete regeneration of the epidermis 3 days after irradiation. Fractional ablative erbium:YAG laser treatment with a pulse stacking technique resulted in histological alterations and shifts in the expression of various genes related to epidermal differentiation, inflammation, and dermal remodeling depending on the treatment setting applied. A standardized in vitro 3D model of human skin proved to be a useful tool for exploring the effects of various laser settings both on skin morphology and gene expression during wound healing. It provides novel data on the gene expression and microscopic architecture of the exposed skin. This may enhance our understanding of laser treatment at a molecular level.
authors.affiliation: Department of Dermatology and Allergology, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany. lschmitt@ukaachen.de.
authors.forename: Laurenz
authors.identifier: http://orcid.org/0000-0003-0989-5587
authors.initials: L
authors.lastname: Schmitt
authors.affiliation: Department of Dermatology and Allergology, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany.
authors.forename: P M
authors.initials: PM
authors.lastname: Amann
authors.affiliation: Department of Dermatology and Allergology, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany.
authors.forename: Y
authors.initials: Y
authors.lastname: Marquardt
authors.affiliation: Department of Dermatology and Allergology, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Heise
authors.affiliation: Department of Dermatology and Allergology, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Czaja
authors.affiliation: Department of Dermatology and Allergology, Medical Faculty, Heinrich-Heine University, Düsseldorf, Germany.
authors.forename: P A
authors.initials: PA
authors.lastname: Gerber
authors.affiliation: Department of Oral and Maxillofacial Surgery, Medical Faculty, RWTH Aachen University, Aachen, Germany.|Interdisciplinary Center for Laser Medicine, Medical Faculty, RWTH Aachen University, Aachen, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Steiner
authors.affiliation: Department of Oral and Maxillofacial Surgery, Medical Faculty, RWTH Aachen University, Aachen, Germany.|Interdisciplinary Center for Laser Medicine, Medical Faculty, RWTH Aachen University, Aachen, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Hölzle
authors.affiliation: Department of Dermatology and Allergology, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany. JensMalte.Baron@post.rwth-aachen.de.|Interdisciplinary Center for Laser Medicine, Medical Faculty, RWTH Aachen University, Aachen, Germany. JensMalte.Baron@post.rwth-aachen.de.
authors.forename: Jens Malte
authors.initials: JM
authors.lastname: Baron
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation / Q000528:radiation effects; D018925:Chemokines / Q000235:genetics / Q000378:metabolism; D002648:Child; D020405:Dermis / Q000528:radiation effects; D000091344:Filaggrin Proteins; D005786:Gene Expression Regulation / Q000528:radiation effects; D006801:Humans; D053685:Laser Therapy / Q000379:methods; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D008297:Male; D008954:Models, Biological; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D012015:Reference Standards; D012867:Skin / Q000528:radiation effects*; D014945:Wound Healing / Q000528:radiation effects
chemical_list: D015415:Biomarkers; D018925:Chemokines; C000717249:FLG protein, human; C000717250:FLG2 protein, human; D000091344:Filaggrin Proteins; D012333:RNA, Messenger
keywords: Fractional erbium:YAG laser; Gene expression; Molecular effects; Organotypic skin equivalents; Resurfacing; Wound healing