Acute effects of fractional laser on photo-aged skin

Association of Early Clinical Response to Laser Rejuvenation of Photoaged Skin with Increased Lipid Metabolism and Restoration of Skin Barrier Function

Laser resurfacing treatments for photoaged skin have improved dramatically over the past decades, but few studies have examined the molecular mechanisms underlying differences in clinical response. Seventeen white female participants with moderate-to-severe photoaging received nonablative fractional laser treatment on the face and forearm once monthly for 6 months. Biopsies for microarray analysis were performed at baseline and 7 days after facial treatment and at baseline and 1, 7, 14, and 29 days after forearm treatment in each participant, resulting in 119 total samples. Participants were stratified into fast (n = 11) and slow (n = 6) responders on the basis of the presence of clinical improvement after the first treatment. Microarray analysis revealed the upregulation of genes associated with matrix metalloproteinases, collagen and extracellular components, TGF-β signaling, double-stranded RNA signaling, and retinoic acid synthesis after treatment that did not differ significantly between fast and slow responders. Cluster and enrichment analyses suggested significantly greater activation of lipid metabolism and keratinocyte differentiation in fast responders, who showed greater upregulation of acyltransferases, fatty acid elongases, fatty acid 2-hydroxylase, fatty acid desaturases, and specific keratins that may contribute to epidermal barrier function. These results create, to our knowledge, a previously unreported atlas of molecular changes that correlate with improvements in photoaging after laser therapy.

Neutrophils and their extracellular traps impair ablative fractional carbon dioxide laser-induced dermal remolding in mice

OBJECTIVES

Ablative fractional CO₂ laser (AFL) therapy is an effective intervention to induce dermal remodeling. AFL treatment of the skin triggers the recruitment of immune cells, with neutrophils dominating the early phase. However, the role of recruited neutrophils in AFL-induced microinjuries and their subsequent dermal remodeling capacity remains elusive.

MATERIALS AND METHODS

A mouse model of AFL-induced dermal remodeling was established. RNA sequencing was used to identify the prominent features of AFL-treated tissues. Histological analysis, including H&E and Masson staining, ultrastructure observation by transmission microscopy, immunofluorescence, and quantitative real-time polymerase chain reaction were used for dermal remodeling analysis. Moreover, AFL-treated mice were intraperitoneally injected with anti-mouse Ly6G antibodies to deplete neutrophils. Neutrophil extracellular traps (NETs) were explored using immunofluorescence, transmission microscopy, and in vitro coculture experiments.

RESULTS

Dermal remodeling, characterized by an increased number of CD31-positve vessels and elevated messenger RNA (mRNA) expression of genes encoding transforming growth factor-β (TGF-β), collagen I, and collagen III, was observed at 15 days after AFL treatment. In the AFL-induced inflammation phase, RNA sequencing identified neutrophil chemotaxis, and degranulation genes were significantly enriched. Histology and immunofluorescence staining of human and mouse tissues harvested at Day 1 after AFL treatment revealed significant neutrophil infiltration surrounding thermal-induced microinjuries. Neutrophil depletion decreased the expression of stress-related genes such as S100A8 and S100A9 in the early phase following AFL treatment. Importantly, neutrophil depletion enhanced dermal remodeling at Day 15, as reflected by enrichment of the extracellular matrix and collagen biosynthesis genes based on RNA sequencing. Moreover, increased collagen I, collagen III, and TGF-β mRNA expression, increased cell proliferation, and vascularity were observed. Interestingly, NETs, which could be induced by AFL-treated fibroblasts in vitro, were identified in both human and mouse tissues on Day 1 after AFL treatment.

CONCLUSIONS

AFL-treated human and mouse skin recruited a large number of neutrophils. The neutrophil surge impaired dermal remodeling in mice. The microenvironment and fibroblast functional modulation mediated by neutrophil degranulation and NET formation were determined to be the underlying mechanisms. Our results indicate that modification of infiltrated neutrophil activity might be a potential therapeutic target for AFL-induced dermal remodeling.

Fractional microneedle radiofrequency device and fractional erbium-doped glass 1,565-nm device treatment of human facial photoaging: a prospective, split-face, random clinical trial

Microneedle fractional radiofrequency (MFR) and non-ablative 1565 nm fractional laser (NAFL) have recently been introduced as new techniques to address the growing concern of facial photoaging. In this prospective randomized split-face study, we wanted to compare the safety and efficacy of MFR with that of NAFL for the treatment of facial photoaging in Asian patients. Fifteen healthy Chinese patients were enrolled for this randomized split-face study. Each patient underwent three sessions of treatment with MFR and NAFL on opposite sides of their face, one month apart. A blinded outcome assessment of the photoaging severity was performed by two independent plastic surgeons on a 5-point visual analogue scale (VAS, 0-4). Patient satisfaction was also scored based on a 5-point VAS (0 = dissatisfaction, 4 = extremely satisfied). Sagging of the nasolabial groove was evaluated using the Antera 3D camera, facial wrinkles and pores using the VISIA skin analysis system. Any adverse events that occurred during the study were also evaluated. Based on the VAS scores and results from the Antera 3D and VISIA, it was noted that there was a significant improvement in facial skin laxity, wrinkles, and pores, and lesser sagging of the nasolabial groove on both the MFR and NAFL sides of the face, compared with that of the baseline. Most patients were satisfied with the treatment and reported tolerable pain and crusting. Although no significant differences were observed between the MFR and NAFL treatments, the NAFL treatment resulted in a shorter downtime(4.56 ± 2.72d) than the MFR treatment(6.96 ± 3.27d). This study confirms the efficacy of MFR and NAFL treatments for facial skin rejuvenation in Asian patients. Furthermore, the therapies were found to be safe and well-tolerated. Our findings suggest that NAFL may be a more convenient treatment modality for facial photoaging because of its shorter downtime. However, sagging of the nasolabial groove was more improved by the MFR treatment than by the NAFL treatment.

Transcriptomic analysis of human skin wound healing and rejuvenation following ablative fractional laser treatment

Ablative fractional laser treatment is considered the gold standard for skin rejuvenation. In order to understand how fractional laser works to rejuvenate skin, we performed microarray profiling on skin biopsies to identify temporal and dose-response changes in gene expression following fractional laser treatment. The backs of 14 women were treated with ablative fractional laser (Fraxel®) and 4 mm punch biopsies were collected from an untreated site and at the treated sites 1, 3, 7, 14, 21 and 28 days after the single treatment. In addition, in order to understand the effect that multiple fractional laser treatments have on skin rejuvenation, several sites were treated sequentially with either 1, 2, 3, or 4 treatments (with 28 days between treatments) followed by the collection of 4 mm punch biopsies. RNA was extracted from the biopsies, analyzed using Affymetrix U219 chips and gene expression was compared between untreated and treated sites. We observed dramatic changes in gene expression as early as 1 day after fractional laser treatment with changes remaining elevated even after 1 month. Analysis of individual genes demonstrated significant and time related changes in inflammatory, epidermal, and dermal genes, with dermal genes linked to extracellular matrix formation changing at later time points following fractional laser treatment. When comparing the age-related changes in skin gene expression to those induced by fractional laser, it was observed that fractional laser treatment reverses many of the changes in the aging gene expression. Finally, multiple fractional laser treatments, which cover different regions of a treatment area, resulted in a sustained or increased dermal remodeling response, with many genes either differentially regulated or continuously upregulated, supporting previous observations that maximal skin rejuvenation requires multiple fractional laser treatments. In conclusion, fractional laser treatment of human skin activates a number of biological processes involved in wound healing and tissue regeneration.

Targeted heat activation of HSP promoters in the skin of mammalian animals and humans

The use of highly inducible HSP promoters for exerting spatial and/or temporal control over the expression of therapeutic transgenes has long been discussed. Localized and time-limited induction of the heat shock response may potentially also be of medical interest. However, such applications would require targeted delivery of heat doses capable of activating HSP promoters in tissues or organs of interest. Accessible areas, including the skin and tissues immediately underneath it, may be most readily targeted. A few applications for heat-directed or heat-controlled therapy in the skin might involve expression of proteins to restore or protect normal skin function, protein antigens for vaccination/immunotherapy, vaccine viruses or even systemically active proteins, e.g., cytokines and chemokines. A review of the literature relating to localized heat activation of HSP promoters and HSP genes in the skin revealed that a multitude of different technologies has been explored in small animal models. In contrast, we uncovered few publications that examine HSP promoter activation in human skin. None of these publications has a therapeutic focus. We present herein two, clinically relevant, developments of heating technologies that effectively activate HSP promoters in targeted regions of human skin. The first development advances a system that is capable of reliably activating HSP promoters in human scalp, in particular in hair follicles. The second development outlines a simple, robust, and inexpensive methodology for locally activating HSP promoters in small, defined skin areas.

Objective evaluation of the efficacy of a non-ablative fractional 1565 nm laser for the treatment of deliberate self-harm scars

Scars resulting from deliberate self-harm (DSH) represent therapeutically challenging forms of scarring due to their highly variable patterns, with no official therapeutic guidelines available. In this pilot study, we aimed to evaluate the effectiveness and safety of a non-ablative fractional Er:glass 1565 nm laser, as a potential new, minimal-invasive approach for the improvement of DSH scars. Sixteen Caucasians suffering from mature DSH scars were included in this clinical study. Patients received a total of three treatments using a non-ablative fractional 1565 nm Er:glass laser every 4 weeks, employing two passes (300 μbeams/cm², 40 mJ, onto the scar; 150 μbeams/cm², 50 mJ, overall area). Measurements included questionnaires (DLQI, POSAS), digital photography, and objective three-dimensional analysis using PRIMOS and VECTRA software at baseline, 1 and 6 months after treatment. PRIMOS objective measurements showed highly significant changes in scar surface with a reduction of atrophic lesions by 27.5% at 6 months follow-up (FU), a decrease in scar height by 42.7% at 6 months FU, resulting in an overall diminished skin irregularity dropping from 678.3 μm at baseline to 441.6 μm throughout the course of the study (p = <0.001 respectively). Improvements in objective measurements were supported by clinical evaluation of scar parameters and showed a strong correlation with enhanced life quality of treated patients. Procedures were well-tolerated, with no lasting negative side effects and little to no downtime. The use of a fractional non-ablative 1565 nm Er:glass laser represents a promising and safe approach for the therapy of DSH scars. Although these scars will never fully resolve, their appearance can be significantly improved to a cosmetically and socially more acceptable appearance.

Treatment of facial photodamage and rhytides using a novel 1,565 nm non-ablative fractional erbium-doped fiber laser

BACKGROUND AND OBJECTIVE

Non-ablative fractional lasers (NAFL) generate microscopic non-contiguous columns of thermal injury in the dermis, resulting in collagen remodeling. This manuscript details our experience with a novel 1,565 nm scanned, erbium-doped fiber NAFL for the treatment of facial photodamage.

STUDY DESIGN/MATERIALS AND METHODS

A prospective, open-label clinical trial was conducted at two clinical sites in the United States on 16 female subjects with a mean age of 49.6 years, Fitzpatrick skin types II to IV, and a baseline Fitzpatrick-Goldman Wrinkle and Elastosis Score (FGWES) of 3-6. Each subject received three treatments at 4-5 week intervals with follow-up assessments at 1, 3, and 6 months after the last treatment.

RESULTS

The mean FGWES demonstrated a statistically significant decrease from baseline both at 3 months (-0.58 ± 0.23, P = 0.02) and 6 months (-0.66 ± 0.22, P = 0.008) after the last treatment. Fifty percent (95%CI [24.21%, 68.49%]) of subjects showed a significant (at least 1 grade) improvement in FGWES from baseline at 3-month follow-up. At least 72% of subjects perceived the results as "moderate" to "very good" at 3 months post-treatment, with comparable satisfaction rates. Treatments were not associated with a high level of pain or discomfort and typical downtime was less than 2 days. No unexpected adverse events or serious adverse events were reported.

CONCLUSION

The 1,565 nm erbium-doped scanned NAFL is an effective treatment for facial wrinkles with a favorable recovery and side effect profile.

Histologic comparison of microscopic treatment zones induced by fractional lasers and radiofrequency

INTRODUCTION

Fractional photothermolysis induces microscopic, localized thermal injury in the skin surrounded by undamaged viable tissue in order to promote wound healing.

OBJECTIVE

This study evaluated acute histologic changes following each single pass of various fractional lasers and radiofrequency (RF).

METHODS

Three male domestic swine were used. We used fractional Erbium:glass (Er:glass), Erbium:yttrium-aluminum-garnet (Er:YAG), CO2 lasers, and fractional ablative microplasma RF. We analyzed features and average values of the diameter, depth, and vertical sectional areas treated with each kind of laser and RF.

RESULTS

The microscopic treatment zone (MTZ) of fractional Er:glass resulted in separation of dermoepidermal junction with no ablative zone. Fractional Er:YAG provided the most superficial and broad MTZ with little thermal collateral damage. Fractional CO2 resulted in a narrow and deep "cone"-like MTZ. Fractional RF resulted in a superficial and broad "crater"-like MTZ.

CONCLUSIONS

This study provides the first comparison of MTZs induced by various fractional lasers and RF. These data provide basic information on proper laser and RF options. We think that these findings could be a good reference for information about fractional laser-assisted drug delivery.

Effects of long-pulsed 1,064-nm neodymium-doped yttrium aluminum garnet laser on dermal collagen remodeling in hairless mice

BACKGROUND

Nonablative lasers are used for dermal collagen remodeling. Although clinical improvements have been reported using various laser devices, the mechanism of dermal collagen remodeling remains unknown.

OBJECTIVE

To investigate the effects of energy fluences of the long-pulsed neodymium-doped yttrium aluminum garnet (Nd:YAG) nonablative laser on dermal collagen remodeling and evaluate the dermal collagen remodeling mechanism.

MATERIALS AND METHODS

Hairless mice were pretreated with ultraviolet B irradiation to produce photo-damage. The laser treatment used a long-pulse 1,064-nm Nd:YAG laser at energy fluences of 20, 40, and 60 J/cm(2) . The amount of dermal collagen and expressions of transforming growth factor beta (TGF-β), matrix metalloproteinase-1 (MMP-1), and tissue inhibitor of metalloproteinase-1 (TIMP-1) of laser treated skin were compared with those of nontreated control skin.

RESULTS

The long-pulse Nd:YAG laser treatment increased dermal collagen and significantly increased TGF-β expression. The expression of MMP-1 decreased with low energy fluence. The expression of TIMP-1 was not significantly different.

CONCLUSION

Long-pulsed 1,064-nm Nd:YAG laser increases the dermal collagen in association with the increased expression of TGF-β.