Ablative Fractional Laser Treatment Research Articles

Transcriptomic Analysis of Early-Stage Basal Cell Carcinomas in Murine Skin Following Topical Treatments With Ablative Fractional Laser and Vismodegib.

Recent studies have demonstrated that ablative fractional laser (AFL) can inhibit the hedgehog pathway, enhance immune infiltration and clear basal cell carcinomas (BCCs) in murine models. In this study, we applied RNA sequencing to further characterise the impact of AFL on the transcriptome of murine skin containing early-stage microscopic BCCs, contrasting it with the effects of topical application of the hedgehog inhibitor vismodegib. Our results showed that BCC induction in murine skin was primarily linked to gene upregulation (significantly upregulated genes: 277, significantly downregulated genes: 24). Characterisation of these genes with Ingenuity Pathway Analysis showed that tumour induction was associated with activation of BCC and Sonic Hedgehog signalling. Both AFL and vismodegib treatments reversed these changes, with vismodegib demonstrating superior performance by reversing most of the upregulated genes (AFL: 59/277; vismodegib: 180/277). Surprisingly, Ingenuity Pathway Analysis also revealed that both AFL and vismodegib treatments caused considerable immune cell infiltration. Based on gene set enrichment analysis and cell type deconvolution, AFL treatment resulted in the largest immune cell recruitment, which for both treatments primarily consisted of infiltrating neutrophils, macrophages and monocytes. In conclusion, the distinct effects observed in BCC skin following AFL and vismodegib treatment suggest key differences between the two interventions. Future applications of AFL or vismodegib treatments could leverage their individual effects, for example by combining the effect of AFL on the immune system with other topical treatments.

50289 Patient-reported levels of itch in hypertrophic scar before and after fractional ablative laser treatment

50289 Patient-reported levels of itch in hypertrophic scar before and after fractional ablative laser treatment

Efficacy and safety of a topical skincare regimen containing CE Ferulic serum and resveratrol BE serum following ablative fractional CO2 laser treatment: A prospective, randomized, split-face, controlled trial.

Ablative fractional CO2 laser is widely used to address various skin problems, but the treatment often leads to adverse effects such as erythema, dyspigmentation, and extended recovery periods, negatively impacting patients' quality of life. This study aimed to evaluate the efficacy and safety of a topical skincare regimen containing both CE Ferulic serum and Resveratrol BE night serum following fractional CO2 laser treatment in Chinese population. In this randomized, investigator-blinded, split-face, controlled trial, individuals aged 18-65 undergoing ablative CO2 laser treatment were randomly assigned to apply CE Ferulic plus resveratrol BE serum (CEF-RBE) to either side of face and normal saline (NS) to the other, for 14 consecutive days. The primary endpoint was erythema index (EI) on day 14, with key secondary endpoints including scabbing detachment time, percentage changes in EI and melanin index (MI), skin hydration, transepidermal water loss, skin sebum content, oedema, and overall subject satisfaction. The study included 51 patients, of whom 29 (56.9%) were female, with a mean (SD) age of 29.8 (5.39) years. On day 14, the CEF-RBE side exhibited significantly lower EI than the NS side (308.9 vs. 325.3, p = 0.034). The median (IQR) time (days) for complete scabbing detachment at the CEF-RBE side was 6.0 (5.0-8.0) compared to 6.5 (5.0-9.0) at NS side (p = 0.018). Additionally, the CEF-RBE side showed a 7.4% decrease in MI from baseline to day 14, while the NS side experienced a 0.2% increase (Δ = -7.6%, p = 0.044). Throughout the 14-day follow-up, the CEF-RBE side consistently displayed higher skin hydration than the NS side. The study highlighted the benefits of incorporating CEF-RBE following laser treatment in reducing erythema and hyperpigmentation, promoting wound healing, and maintaining skin hydration, although limitations such as contamination and adherence issues should be considered.

The effect of combined red, blue, and near-infrared light-emitting diode (LED) photobiomodulation therapy on speed of wound healing after superficial ablative fractional resurfacing

Objective of the study is to assess the effects of wound healing with a commercially available light emitting diode (LED) photo biomodulation (PBM) device that emits three wavelengths (465, 640 and 880nm) after ablative fractional laser (AFL) treatment to healthy skin on the bilateral inner biceps. We conducted a prospective intraindividual randomized controlled study with 25 volunteers. AFL treatment was performed on healthy skin of the bilateral inner biceps. Subjects applied the LED light device for 30 min to the assigned bicep 3 times a week over 4 weeks, beginning on day 0. Subjects were followed up on days 2, 4, 6, 9, 13, 20 and 27 for treatment with the PBM device, clinical digital photography of the test and control sites, and in-person subject assessment, with follow ups on days 34 and 55 for clinical photography and assessment. Three blinded evaluators were asked to determine which bicep healed faster between day 0 to day 13. Pain, discomfort, and itch were also assessed. The three blinded evaluators chose the treatment arm as the faster healed arm in greater than 50% of the images, although the results were not statistically significant. There was no statistically significant difference between test and control arms in terms of pain, discomfort and itch. In conclusion, PBM therapy has the potential to improve wound healing. In this study, a three wavelength PBM device resulted in some subjects achieving faster healing after AFL but the results were not statistically significant.

Ablative fractional CO2 laser treatment promotes wound healing phenotype in skin macrophages.

Ablative fractional laser (AFL) treatment is a well-established method for reducing signs of skin photoaging. However, the biological mechanisms underlying AFL-induced healing responses and skin rejuvenation remain largely unknown. It is known that macrophages play an important role in orchestrating healing, normalization, and remodeling processes in skin. Macrophage phenotypes are characterized by inflammatory markers, including arginase-1 (Arg1), major histocompatibility class II molecules (MHC II), and CD206. This study aims to explore AFL's effect on macrophage phenotype by evaluating changes in inflammatory markers and the potential concurrent accumulation of Arg1 in the skin. Mice (n = 9) received a single AFL treatment on the left side of the back skin (100 mJ/microbeam, 5% density) while the right side of the back remained untreated as control. Treated and untreated skin from each mouse were collected Day 5 posttreatment for flow cytometry and histology analysis. Flow cytometry evaluated the immune infiltration of macrophages and the expression of macrophage inflammatory markers (Arg1, MHC II, and CD206). In addition, Arg1 presence in the skin was evaluated through antibody staining of histology samples and quantification was performed using QuPath image analysis software. Following AFL, the number of macrophages increased 11-fold (p = 0.0053). Phenotype analysis of AFL-treated skin revealed an increase in the percentage of macrophages positive for Arg1 (p < 0.0001) and a decrease in the percentage of macrophages positive for MHC II (p < 0.0001) compared to untreated skin. No significant differences were observed in percentage of CD206-positive macrophages (p = 0.8952). Visualization of AFL-treated skin demonstrated a distinct pattern of Arg1 accumulation that correlated with the microscopic treatment zones (MTZ). Quantification of the percentage of Arg1-positive area in epidermis and dermis showed a significant increase from 3.5% ± 1.2% to 5.2% ± 1.7 (p = 0.0232) and an increase from 2.2% ± 1.2% to 9.6% ± 3.3 (p < 0.0001) in whole skin samples. AFL treatment polarizes macrophages toward a wound healing phenotype and induces Arg1 accumulation in the MTZ. We propose that the polarized wound healing macrophages are a major source for the increased Arg1 levels observed in the skin following treatment.

Efficacy and safety of bipolar fractional radiofrequency vs. 2940-nm Er:YAG ablative fractional laser in striae distensae treatment: A split abdomen study.

Striae distensae (SD) is a challenging cosmetic condition. Ablative fractional laser (AFL) is an effective method for treating SD. Recently, fractional radiofrequency (FRF) has been shown to be a promising treatment for SD; however, few studies have shown the differences between FRF and AFL in the treatment of SD. This study aimed to evaluate and compare the clinical efficacy and safety of bipolar FRF with 2940-nm erbium yttrium aluminum garnet (Er:YAG) AFL in the treatment of SD. Twenty volunteers with abdominal SD were enrolled in this study. One half of the abdomen was treated with 2940-nm Er:YAG AFL, whereas the other half was treated with bipolar FRF, with three sessions at 4-week intervals. Photographic evaluations of clinical improvement were conducted by two independent investigators before and after treatment, and the patients provided self-assessments. Two participants underwent three punch biopsies, one before treatment and two obtained from bilateral representative skin lesions on the abdomen 3 months following the final treatment. Clinical improvements were observed in SD on both sides of the abdomen after the two treatments. Post-treatment skin biopsies revealed increased thickness in the epidermis and dermis, and higher collagen and elastin density compared to those at the baseline. No statistically significant differences were observed in the clinical outcomes between the two treatment approaches. The efficacy and safety of bipolar FRF treatment are comparable to those of 2940-nm Er:YAG AFL treatment, providing an alternative and effective treatment for SD.

Ablative fractional laser treatment reduces hedgehog pathway gene expression in murine basal cell carcinomas

This study aimed to investigate the impact of ablative fractional laser (AFL) on hedgehog pathway gene expression in murine microscopic basal cell carcinomas (BCCs) and compare these results to the effect of topical treatment with vismodegib, an FDA-approved hedgehog inhibitor. In 25 mice, 1 cm2 skin test sites (n = 44) containing microscopic BCCs were exposed to one of three interventions: a single CO2 AFL treatment (1 pulse, 40 mJ/microbeam, wavelength 10.6 μm, 5% density, pulse rate 250 Hz, n = 12), eight topical vismodegib treatments (3.8 mg/mL, n = 8), or combination of AFL and vismodegib treatments (n = 9). Untreated controls were included for comparison (n = 15). After 4 days, skin samples were analyzed for hedgehog gene expression (Gli1, Gli2, and Ptch1) by qPCR and vismodegib concentrations by liquid chromatography mass spectrometry (data analyzed with two-tailed t-tests and linear regression). A single treatment with AFL monotherapy significantly reduced hedgehog gene expression compared to untreated controls (Gli1 72.4% reduction, p = 0.003; Gli2 55.2%, p = 0.010; Ptch1 70.9%, p < 0.001). Vismodegib treatment also reduced hedgehog gene expression (Gli1 91.6%; Gli2 83.3%; Ptch1 83.0%), significantly surpassing AFL monotherapy for two out of three genes (Gli1, p = 0.017; Gli2, p = 0.007; Ptch1, p = 0.15). AFL and vismodegib combination mirrored the effects of vismodegib monotherapy (Gli1, p = 0.424; Gli2, p = 0.289; Ptch1, p = 0.593), possibly due to comparable cutaneous vismodegib concentrations (mean ± SD, vismodegib monotherapy 850 ± 475 µmol/L; combination 1036 ± 824 µmol/L; p = 0.573). In conclusion, a single AFL treatment significantly reduced hedgehog gene expression in murine BCCs mimicking the effects of eight topical applications of vismodegib. Further studies are needed to assess whether AFL can be utilized for BCC treatment, either as monotherapy or in combination with other drugs.

Efficacy of erbium yttrium aluminium garnet laser on post-traumatic scars among Indian population – A non-randomized study

Objectives: The post-trauma scar is a common problem; it can produce physical and psychological difficulties to the patient. The use of ablative and non-ablative lasers based on the fractional approach is emerging as a method to treat scars. However, very limited data are available of the same in patients of South India. In this study, the authors demonstrated the efficacy of ablative fractional resurfacing (AFR) for traumatic scars using a 2940-nm erbium: yttrium-aluminum-garnet (Er: YAG) laser for the treatment of post-traumatic scars in patients of south India. Material and Methods: Seventy-three scars were enrolled in adults of age between 18 and 60 years. Each scar was treated four times at 1-month intervals with a fractional ablative 2940-nm Er: YAG laser using the same parameters. Pre-treatment evaluation before the initiation of the treatment and post-treatment evaluation was performed 1 month after the fourth treatment session of laser. The scar was evaluated using Vancouver scar scale (VSS). Results: All 73 scars completed the study. After ablative fractional laser treatment, all treated portions of the scars showed improvements, as demonstrated by the VSS. Conclusion: This study shows that ablative fractional application of Er: YAG laser treatment of scars reduces scars fairly. The authors suggest that treatment using AFR can be a adjuvant scar management method for improving the quality of life of patients with post-traumatic scars in patients of south India.

In vivo characterization of laser-assisted delivery of hyaluronic acid using multiphoton fluorescence lifetime imaging.

Laser-assisted drug delivery (LADD) is a treatment method to enhance the penetration of pharmaceuticals through the skin. The aim of the present study is to track hyaluronic acid (HA) and analyse its effect on human skin invivo after ablative fractional laser (AFL) treatment. Healthy male and female subjects were recruited. Four areas were marked on their forearms of each volunteer, and each area was assigned to one of the following treatment options: AFL + HA, AFL only, HA only or untreated control. A carbon dioxide laser was used for the AFL treatment. Follow-up measurements were scheduled 30 min and 30 days after treatment using multiphoton tomography equipped with fluorescence lifetime imaging (MPT-FLIM). A total of 11 subjects completed the study. By detecting fluorescence lifetimes, the HA and the anaesthetic ointment were clearly distinguishable from surrounding tissue. After AFL treatment, HA could be visualized in all epidermal and upper dermal layers. In contrast, HA in intact skin was only detected in the superficial layers at distinctly lower levels. The applied HA gel seemed to have beneficial properties for the wound healing process after laser treatment. LADD has proven to be a fast and effective method to increase HA uptake into the skin, allowing for improved hydration and skin rejuvenation over time. Furthermore, LADD could be a beneficial treatment option in laser resurfacing. MPT-FLIM proved to be an appropriate diagnostic tool for drug delivery tracking and monitoring of treatment response for individualized therapy adjustment.

SMOOTH protocol: A pilot randomised prospective intra-patient single-blinded observational study for examining the mechanistic basis of ablative fractional carbon dioxide laser therapy in treating hypertrophic scarring.

Burn injuries are the fourth most common type of trauma and are associated with substantial morbidity and mortality. The impact of burn injury is clinically significant as burn injuries often give rise to exuberant scarring. Hypertrophic scarring (HTS) is a particular concern as up to 70% of burns patients develop HTS. Laser therapy is used for treating HTS and has shown positive clinical outcomes, although the mechanisms remain unclear limiting approaches to improve its effectiveness. Emerging evidence has shown that fibroblasts and senescent cells are important modifiers of scarring. This study aims to investigate the cellular kinetics in HTS after laser therapy, with a focus on the association of scar reduction with the presence of senescent cells. We will conduct a multicentre, intra-patient, single-blinded, randomised controlled longitudinal pilot study with parallel assignments to achieve this objective. 60 participants will be recruited to receive 3 interventional ablative fractional CO2 laser treatments over a 12-month period. Each participant will have two scars randomly allocated to receive either laser treatment or standard care. Biopsies will be obtained from laser-treated, scarred-no treatment and non-scarred tissues for immune-histological staining to investigate the longitudinal kinetics of p16INK4A+-senescent cells and fibroblast subpopulations (CD90+/Thy1+ and αSMA+). Combined subjective scar assessments including Modified Vancouver Scar Scale, Patient and Observer Scar Assessment Scale and Brisbane Burn Scar Impact Profile; and objective assessment tools including 3D-Vectra-H1 photography, DermaScan® Cortex, Cutometer® and ColoriMeter®DSMIII will be used to evaluate clinical outcomes. These will then be used to investigate the association between senescent cells and scar reduction after laser therapy. This study will also collect blood samples to explore the systemic biomarkers associated with the response to laser therapy. This study will provide an improved understanding of mechanisms potentially mediating scar reduction with laser treatment, which will enable better designs of laser treatment regimens for those living with HTS. ClinicalTrials.gov: NCT04736251.

41296 Fluorescence visualization of doxycycline distribution following ablative fractional laser treatment

41296 Fluorescence visualization of doxycycline distribution following ablative fractional laser treatment

Efficacy of Ablative Fractional Carbon Dioxide Laser Alone and Combined with Platelet-Rich Plasma in the Treatment of Androgenetic Alopecia

Abstract Androgenetic alopecia (AGA) is a common form of hair loss in both men and women. In men, this condition is also known as male-pattern baldness. Fractional CO2 laser treatment has effectively induced hair regrowth through the wound-healing process. Platelet-rich plasma (PRP) ensures local delivery of growth factors, modification of the inflammatory response, and stimulation of cell proliferation and differentiation within the target tissue. PRP therefore showed a beneficial effect in treatment of AGA. Aim of the Study The aim of this study is to evaluate and compare the efficacy and safety of ablative carbon dioxide (CO2) fractional laser alone or combined with platelets rich plasma therapy in the treatment of Male Androgenetic Alopecia. Patients and Methods The study included 35 patients suffering from AGA. All patients will receive bilateral ablative fractional CO2 laser treatment on the alopecic scalp and the right or left side of the scalp will be randomly selected to be covered with platelet-rich plasma and the other half of the scalp will be covered with saline after the laser at the same session. Results Combined ablative fractional CO2 laser treatment and platelet-rich plasma showed statistically significant improvement compared to ablative fractional CO2 laser alone.

Cosmetic therapies for Chinese patients with acne taking concomitant or recent intake of oral isotretinoin: A retrospective study.

The current standard recommendation is to initiate the cosmetic therapies after discontinuing taking oral isotretinoin for at least 6 months. However, this recommendation has been questioned in several recent publications, and it is difficult to operate in clinical practice as early initiation of effective treatment is desirable for patients with acne sequelae. The purpose of this study is to evaluate the efficacy and safety of chemical peeling and light/laser or radiofrequency treatments combined with oral isotretinoin for patients with acne vulgaris and acne scars. A retrospective study of 511 patients on/or recently administered with isotretinoin treated with glycolic acid, intense pulsed light, nonablative fractional laser, fractional radiofrequency, and ablative carbon dioxide laser. A total of 1352 interventions were performed. The medical follow-up lasted for at least 1 year. The efficacy and safety of different procedures were evaluated. A total of 511 patients, who were treated with isotretinoin orally or stopped for <6 months, received 477 sessions of glycolic acid chemical peeling treatment, 588 sessions of intense pulsed light treatment, 61 sessions of nonablative fractional laser treatment, 101 sessions of fractional radiofrequency treatment, and 125 sessions of ablative fractional carbon dioxide laser treatment. No hypertrophic scars and keloids were found, and the incidence of serious adverse reactions such as scarring, erythema, blisters, and postinflammatory hyperpigmentation did not increase. It is safe to perform skin procedures in patients with acne and acne scars during or after discontinuation of isotretinoin for <6 months. Invasive treatments such as ablative fractional carbon dioxide laser treatment can be performed, as appropriate, by an experienced physician. The guideline of avoiding chemical and physical procedures in such patients taking oral isotretinoin should to revised.

Characterization of an ablative fractional CO2 laser-induced wound-healing model based on in vitro 3D reconstructed skin.

This study describes the development and characterization of a novel in vitro wound-healing model based on a full-thickness reconstructed skin by exposing the tissue to fractional ablative laser treatment. A 3D full-thickness skin model was fabricated and treated with fractional ablative CO2 laser. Wound-healing process was characterized by HE staining, noninvasive OCT imaging, immunostaining, as well as transepidermal water loss measurement. Cytokines and proteins involved in the inflammatory and dermal remodeling process were studied by ELISA and protein array assays. Fractional ablative CO2 treatment induced a wound zone of 9 mm in diameter, containing 56 micro-wounds with 200 μm diameter and 500-700 μm in depth on reconstructed full-thickness skin model. HE staining revealed a typical wound morphology and healing process with migration of keratinocytes, formation and extrusion of necrotic tissue, and cell inclusion in dermis, which correlates with clinical observations. Based on OCT and TEWL measurements, the re-epithelialization took place over 2 days. Laser-triggered keratinocytes proliferation and differentiation were demonstrated by activated Ki67 and Filaggrin expression respectively. Injury-invoked cytokine ICAM-1 showed instant upregulation on Day 1. Decreased epidermis thickness and depression of IGFBP-2 protein level synergistically indicated the unavoidable thermal side effects from laser treatment. Downregulated DKK-1 protein level and upregulation of α-SMA together implicated the risk of potential fibrosis post-laser treatment. This in vitro laser wounded reconstructed skin model captured the key events of wound-healing process, could be used to investigate the mechanisms of wound-healing triggered by a commonly used beauty procedure, and also provides a valuable tool for evaluating the efficacy of novel actives for the post-procedure application.

Combination of Fractional Microneedling Radiofrequency and Ablative Fractional Laser versus Ablative Fractional Laser Alone for Acne and Acne Scars.

Fractional microneedle radiofrequency (FMR) systems are used to treat inflammatory acne and scarring. Nonetheless, few controlled studies have combined this treatment with the traditional ablative fractional laser (AFL). We aimed to assess the safety and efficacy of the combination of FMR and AFL versus AFL alone in treating acne and acne scars. In this 20-week, randomized, split-face study, 23 Korean patients with facial acne and acne scars underwent FMR and AFL treatments. One half of each patient's face was randomly assigned to receive FMR+AFL, whereas the other half received AFL alone. Treatments were administered in three consecutive sessions at 4-week intervals. This study investigated the severity of inflammatory acne, acne scars, individual lesion counts, depressed scar volumes, as well as patient and physician satisfaction. In addition, five patients underwent skin biopsy, and sebum output was measured. The FMR+AFL treatment demonstrated superior efficacy compared to AFL alone in terms of inflammatory acne and acne scar grading, lesion counts, and subjective satisfaction. The side effects were minimal and well-tolerated in both groups. Immunohistochemical findings from skin biopsy samples revealed that the application of FMR+AFL could induce an inhibitory effect on sebum secretion at the molecular level. FMR combined with AFL is a well-tolerated and effective treatment modality for inflammatory acne and acne scarring.

Repeated exposure to fractional CO2 laser delays squamous cell carcinoma formation and prevents clinical and subclinical photodamage visualized by line-field confocal optical coherence tomography and histology.

Ablative fractional laser (AFL) is a well-established modality for treating ultraviolet radiation (UVR)-induced skin photodamage. We aimed to investigate the potential of AFL to delay squamous cell carcinoma(SCC) formation and prevent photodamage in a preclinical UVR-induced SCC model. Hairless C3.Cg-Hrhr /TifBomTac mice (n = 50) were exposed to UVR three timesweekly throughout the study. UV-exposed mice were randomized to two groups that received dorsal CO2 AFL (10 mJ/mb, 10% density) or no treatment. AFL was performed every other week for a total of 16 weeks (nine treatments in total). The primary outcome was time to tumor occurrence. In a subset of mice on Day 150, prevention of clinical photodamage was assessed by examination of skin tightness and dyspigmentation. Concomitantly, assessment of subclinical photoprevention based on normalization of keratinocyte dysplasia, dermo-fiber morphology (collagen and elastin fibers), and skin thickness, was performed using line-field confocal optical coherence tomography (LC-OCT) and histology. Repeated AFL treatments delayed SCC tumor development compared to UVR control mice by 12, 19, and 30 days for first, second, and third tumors, respectively (p ≤ 0.0017). Compared to UVR controls, AFL prevented photodamage both clinically and subclinically, based on LC-OCT and histology. In the epidermal layer, AFL imparted photopreventative effects including reduced dyspigmentation and keratinocyte dysplasia (1 vs. 2.5, p = 0.0079) and partial normalization of the epidermal thickness (p < 0.0001). In the dermis, AFL led to twofold greater skin tightness (p = 0.0079), improved dermo-fiber structure, and dermal thickness (p = 0.0011). In conclusion, repeated AFL treatments of UVR-exposed skin significantly delayed SCC tumor formation and prevented clinical and imaging-assessed subclinical signs of photodamage, indicating a potential for AFL in prevention strategies for SCC and photodamage in high-risk populations.

609 Available non-invasive skin probes distinguish between normal skin and hypertrophic scar but not laser-treated scar

IntroductionSkin fibrosis is the most under-studied fibrotic condition, and as such, there are limited treatment options for hypertrophic scar (HTS). HTS is difficult to study because scars improve over time, thus making the distinction between natural improvements and interventions difficult. In addition, clinical, histologic, cellular, and molecular outcome metrics are not agreed upon among providers/researchers. It was hypothesized that a set of non-invasive skin probes would be able to distinguish between HTS and normal skin (NS), but not between HTS before and after treatment with fractional ablative laser, despite histologic-level evidence showing improvement with treatment.MethodsWounds were created and HTS were allowed to form (n=8 scars). At Day 77, HTS and NS (n=4) were assessed with non-invasive skin probes measuring elasticity and trans-epidermal water loss (TEWL). HTS were then treated with CO2 fractional ablative laser (FLSR) at 70 mJ, 250Hz, and 1% density. The same data, sample collection, and FLSR treatment was carried out at weeks 1, 2, 3 and 4. Formalin-fixed biopsies were processed and stained with H&E, Herovici, Masson’s Trichrome, and Picrosirius red stains. Collagen type and architecture were qualitatively evaluated. Rete ridge ratio (RRR) was calculated from H&E stains.ResultsAll stains distinguished between HTS and NS with ease. Herovici stain showed differences in collagen architecture and collagen type after treatment with FLSR. Pre laser treatment, elasticity was different between HTS and NS (290.50±32.90 N/m vs. 90.92±5.61 N/m, p< 0.001). However, elasticity did not change after FLSR at 1, 2, 3, or 4 weeks (248.17±48.54, 215.54±44.68, 295.29±37.5, 290.79±30.17, p >0.05). RRR was different between HTS and NS (1.22±0.11 vs. 1.51±0.03, p=0.08). FLSR induced a significant increase in RRR in HTSs (pre=1.3±0.1 vs. week 4=1.9±0.1, p< 0.05). Pre-treatment, TEWL was different between HTS and NS (12.96±1.99 g/m2h vs. 8.72±1.11 g/m2h, p=0.09). However, TEWL did not change after FLSR at 1, 2, 3, or 4 weeks (15.95±1.99, 20.35± 3.15, 15.9±1.96, 14.01±2.22, p >0.05).ConclusionsOutcome metrics that non-invasively measure the qualities of scar are critical for HTS research to evaluate treatment effectiveness. Currently available technologies distinguish between NS and HTS well. However, they are inadequate to distinguish scars pre- and post-treatment despite evidence at the histologic level that changes occur. New technologies should be developed that are able to more effectively demonstrate changes to HTS after treatment.

Treatment of acne scars with fractional carbon dioxide laser in Asians: a retrospective study to search for predicting factors associated with efficacy.

Ablative fractional laser treatment has been extensively used for resurfacing atrophic acne scars. However, few studies have investigated how the parameters set during laser procedures affect efficacy. In this retrospective study, we examined the relationship between efficacy and Fitzpatrick skin type, gender, age, follow-up duration, energy, and treatment sessions utilizing ablative fractional carbon dioxide (CO2) laser in Asians with Fitzpatrick skin types III-IV. We then analyzed the relationship between outcome and adverse effects including hyperpigmentation. Three blinded dermatologists used the ECCA (Echelle d'Evaluation Clinique des Cicatrices d'Acnluation Clinique des Cicospectively review 82 of 1034 patients who presented at our institution for atrophic acne scar treatment between August 2013 and August 2019. Factors associated with efficacy, including age, gender, Fitzpatrick skin type, energy, treatment sessions, follow-up duration, and pigmentation, were analyzed. 82 patients met inclusion criteria. Patients underwent one to three CO2 laser treatment sessions. Parameter settings for individual patients were consistent across treatments. Mean ECCA scores decreased from 102.70 ± 24.95 to 87.28 ± 24.48 (p ≤ 0.001). The number of treatment sessions and duration of pigmentation lasting shorter than 3months positively correlated with better outcomes. All patients had erythema, which lasted longer than 3months in 16 patients (19.51%). Post-inflammatory hyperpigmentation (PIH) affected 60 patients (73.17%) and lasted longer than 3months in 26 patients (31.71%). One patient experienced hypopigmentation (1.22%), while 8 experienced acne flare-up (9.76%). Post-laser scars occurred in 2 patients (2.44%). Our data suggest that in atrophic acne scar treatment in Asians using fractional CO2 laser, 3 treatment sessions and duration of hyperpigmentation within 3months have better outcomes regardless of energy, gender, age, Fitzpatrick skin type, follow-up duration, and disease course.

Laser Treatment of Hypopigmentation in Scars: A Review.

Despite history of multiple treatment modalities, repigmentation of hypopigmented scars remains a difficult clinical problem. The purpose of this review is to evaluate the literature on laser and combination laser plus adjunct topical therapy for hypopigmented burn and traumatic scars. A search on PubMed and on Oxford Academic was conducted with additional relevant literature obtained from reference lists. Treatment regimens that address hypopigmentation within scars were reviewed. A combination of nonablative fractional or ablative fractional laser treatment with topical prostaglandin analogue with or without topical retinoid were found to result in superior repigmentation. Reliable improvement of hypopigmentation in scars after laser treatment is challenging. Laser can achieve success in some cases. Ultraviolet laser can achieve modest repigmentation; however, results are short-lived and require continued re-treatment. Modest improvement in pigmentation is seen with nonablative fractional laser or ablative fractional laser alone and enhanced repigmentation is demonstrated when combining fractional laser resurfacing with topical application of synthetic prostaglandin analogues and other known modulators of melanogenesis.

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.