Molecular mechanisms of nonablative fractionated laser resurfacing

The Effect of Fractional Carbon Dioxide Laser on Melanogenesis in Human Melanocytes and Vitiligo Mouse Models

Introduction

Vitiligo is an acquired skin pigmentation disorder, the cause of which is poorly understood. Researchers in this field are dedicated to exploring novel treatments for achieving re-pigmentation.

Methods

Mice were randomly selected and divided into control, model, and model+laser groups. Evaluate the impact of different levels of carbon dioxide laser irradiation on tyrosinase activity, melanocyte viability, and melanin content.

Results

In this study, it was found that the cell viability and melanin content were significantly enhanced in human melanocytes after treatment with different energy densities of fractional carbon dioxide laser. In addition, laser-treated vitiligo mouse models showed mild pathological changes.

Discussion

Therefore, we believe that fractional carbon dioxide laser may be a potential adjunctive modality for treating vitiligo.

Increased susceptibility to ischemia causes exacerbated response to microinjuries in the cirrhotic liver

Fractional laser ablation is a technique developed in dermatology to induce remodeling of skin scars by creating a dense pattern of microinjuries. Despite remarkable clinical results, this technique has yet to be tested for scars in other tissues. As a first step toward determining the suitability of this technique, we aimed to (1) characterize the response to microinjuries in the healthy and cirrhotic liver, and (2) determine the underlying cause for any differences in response. Healthy and cirrhotic rats were treated with a fractional laser then euthanized from 0 h up to 14 days after treatment. Differential expression was assessed using RNAseq with a difference-in-differences model. Spatial maps of tissue oxygenation were acquired with hyperspectral imaging and disruptions in blood supply were assessed with tomato lectin perfusion. Healthy rats showed little damage beyond the initial microinjury and healed completely by 7 days without scarring. In cirrhotic rats, hepatocytes surrounding microinjury sites died 4-6 h after ablation, resulting in enlarged and heterogeneous zones of cell death. Hepatocytes near blood vessels were spared, particularly near the highly vascularized septa. Gene sets related to ischemia and angiogenesis were enriched at 4 h. Laser-treated regions had reduced oxygen saturation and broadly disrupted perfusion of nodule microvasculature, which matched the zones of cell death. Our results demonstrate that the cirrhotic liver has an exacerbated response to microinjuries and increased susceptibility to ischemia from microvascular damage, likely related to the vascular derangements that occur during cirrhosis development. Modifications to the fractional laser tool, such as using a femtosecond laser or reducing the spot size, may be able to prevent large disruptions of perfusion and enable further development of a laser-induced microinjury treatment for cirrhosis.

Dynamic panoramic presentation of skin function after fractional CO2 laser treatment

Fractional CO2 laser, as a typical ablative laser, has been used to assist in the treatment of many skin diseases, such as photoaging, atrophic scar, hypertrophic scar, superficial pigmentation, vitiligo, and so on. However, the dynamic changes in skin function after fractional CO2 laser treatment are still unclear. This study explored the changes in local skin function and possible regulatory mechanisms after fractional CO2 laser treatment for 1, 3, 5, and 7 days through transcriptome high-throughput sequencing. The results showed that fractional CO2 laser tended to transform the "lesions" into "normal skin", regulate the skin barrier, coordinate the rearrangement of collagen, enhance the local microvascular circulation, activate the immune system to secrete a large number of cytokines, and act as an auxiliary tool to assist drug transport. In conclusion, according to the basic principle of destruction before reconstruction, fractional CO2 laser plays a key role of balancer in skin reconstruction.

LASER treatment in gynaecology -A randomized controlled trial in women with symptomatic lichen sclerosus

OBJECTIVE

Aim of our study was to evaluate the therapeutic effect of laser treatment in vulvar lichen sclerosus, mainly the reduction of existing symptoms as itching, burning and pain. We asked about the different outcome by using different application doses.

STUDY DESIGN

We conducted a prospective randomized double-blind dose-controlled trial in our dysplasia unit specializing vulvar disorders. 67patients with active LS were included. LS was confirmed by biopsy or by the validated CSS (clinical scoring system of vulvar LS). Computer generated randomization resulted in two groups, each group received a different application dose.(LDG- low dose group, NDG- normal dose group) During the study period of 18 weeks all participants received three laser applications in three subsequent sessions of three weeks. Two follow-ups six and twelve weeks after the first application was performed. At every visit, the participants filled in the VAS (visual analogue scale) for recording the actual vulvar symptoms as itching burning or pain on a range from 0 to 10.

RESULTS

Before treatment the mean VAS-Score was 4.3 (STD ± 2.4) in the NDG and 5.1(±2.6) in the LDG. After 18 weeks, the mean reduction was -2.4 (±2.3) for NDG and -2.7 (±2.8) for LDG. Four patients (two of each group) reported more pain after than before treatment. Both groups show significant lower VAS-Scores 18 weeks after the treatment than before therapy (p < 0.0001). The reduction of symptoms after 18 weeks between NDG and LDG was not significant (p = 0.6244).

CONCLUSION

Laser treatment with the microablative CO2 laser leads to a significant improvement for symptoms of LS. A higher dosage of laser radiation shows no benefit concerning the symptoms. We have not observed any serious adverse events during this study.

Scar Management and Dyschromia: A Summary Report from the 2021 American Burn Association State of the Science Meeting

Burn scars, and in particular, hypertrophic scars, are a challenging yet common outcome for survivors of burn injuries. In 2021, the American Burn Association brought together experts in burn care and research to discuss critical topics related to burns, including burn scars, at its State of the Science conference. Clinicians and researchers with burn scar expertise, as well as burn patients, industry representatives, and other interested stakeholders met to discuss issues related to burn scars and discuss priorities for future burn scar research. The various preventative strategies and treatment modalities currently utilized for burn scars were discussed, including relatively noninvasive therapies such as massage, compression, and silicone sheeting, as well as medical interventions such as corticosteroid injection and laser therapies. A common theme that emerged is that the efficacy of current therapies for specific patient populations is not clear, and further research is needed to improve upon these treatments and develop more effective strategies to suppress scar formation. This will necessitate quantitative analyses of outcomes and would benefit from creation of scar biobanks and shared data resources. In addition, outcomes of importance to patients, such as scar dyschromia, must be given greater attention by clinicians and researchers to improve overall quality of life in burn survivors. Herein we summarize the main topics of discussion from this meeting and offer recommendations for areas where further research and development are needed.

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.

Early acne scar intervention with 1064 nm picosecond laser in patients receiving oral isotretinoin: a randomized split-face controlled pilot study

Early acne scar intervention is important. Oral isotretinoin is widely used in patients with moderate to severe acne. Picosecond laser has shown a promising effect on scar clearance. However, there is a lack of reports on the efficacy and safety of early acne scar management by using 1064-nm picosecond laser in patients receiving low-dose oral isotretinoin. Twenty-four patients with atrophic acne scars of Fitzpatrick skin type III to V were enrolled. All patients were receiving low-dose oral isotretinoin (0.12-0.22 mg/kg/day) during the treatment. The face of the participants was randomly assigned to receive 2 sessions of fractional picosecond 1064 nm Nd: YAG laser (FxPico) treatment and 2 follow-ups, with an interval of 1 month (month 0-3). Clinical efficacy and safety were assessed by photographs, ECCA grading scale, the number of scar lesions melanin and erythema indexes (MI and EI), TEWL, DLQI, and patient satisfaction and the adverse events were recorded on every visit. FxPico significantly decreased the ECCA score and showed higher improvement in the ECCA score. FxPico treated side achieved a significant reduction in all acne scar types, while only boxcar scars and rolling scars showed higher improvement. TEWL but not MI or EI were significantly improved. DLQI and patient satisfaction were higher with the FxPico-treated side than control side. No adverse effects were observed and all the side effects observed were temporary and tolerable. Early intervention by FxPico on patients receiving low-dose oral isotretinoin is a safe and effective modality to improve atrophic acne scars.

Review of Lasers and Energy-Based Devices for Skin Rejuvenation and Scar Treatment With Histologic Correlations

BACKGROUND

Lasers and energy-based devices (EBD) are popular treatments for skin rejuvenation and resurfacing. Achieving desired outcomes and avoiding complications require understanding the effects of these devices at a histologic level. Currently, no comprehensive review summarizing the histologic effects of laser and energy-based treatments exists.

OBJECTIVE

To describe how lasers and EBD alter skin histology and improve the overall understanding of these devices.

MATERIALS AND METHODS

A PubMed search was conducted for studies with histologic analysis of fractional picosecond laser, fractional radiofrequency microneedling, nonablative lasers, and ablative lasers.

RESULTS

Fractional picosecond lasers induce intraepidermal and/or dermal vacuoles from laser-induced optical breakdown. Fractional radiofrequency microneedling delivers thermal energy to the dermis while sparing the epidermis, making it safer for patients with darker skin phototypes. Fractional nonablative lasers induce conical zones of coagulation of the epidermis and upper dermis. Ablative lasers vaporize the stratum corneum down to the dermis. Traditional ablative lasers cause diffuse vaporization while fractional ablative lasers generate columns of tissue ablation.

CONCLUSION

Lasers and EBD are effective for skin resurfacing and rejuvenation and have different mechanisms with disparate targets in the skin. Safe and effective use of devices requires understanding the histologic laser-tissue interaction.

Molecular Features of Hypertrophic Scars After Thermal Injury: Is There a Biologic Basis for Laser Therapy?

Significance: Hypertrophic scars (HTS) and keloids are common after thermal injuries and other trauma to deep regions of dermis of the skin. These abnormal scars can cause contractures and the thick masses of scar tissue that result in functional and cosmetic impairment. Management of these dermal fibrotic conditions includes a wide range of medical and surgical treatments, which can be time consuming, only partially effective, and often uncomfortable for patients. Recent Advances: The molecular pathophysiology of HTS has become more understood over the past two decades, where thermal injury to the reticular dermis results in an inflammatory response, fibrogenic growth factor release, and the formation of a dermal scar with increased collagen and proteoglycan composition in an abnormal morphology. Lasers are becoming a widely used form of treatment for these types of scars; however, the evidence for the beneficial effects of laser treatments and the understanding of their mechanism of action are still evolving. Critical Issues: Paradoxically, laser delivery of thermal energy to the skin is suggested to improve scar remodeling and wound healing, yet HTS is a well-recognized complication of excessive thermal energy delivered by laser treatments. This review aims to examine the current evidence for the use of lasers for HTS, and to investigate the molecular mechanisms where re-injury of a burn scar from laser treatment could result in overall improvements in scar quality. Future Directions: Improved design of clinical trials for the treatment of scarring in the future will evolve from new methodology and models of HTS in animals and humans.

"Split-Face" Evaluation of Collagen Changes Induced by Periorbital Fractional CO2 Laser Resurfacing

BACKGROUND

Periorbital fractional CO2 laser resurfacing has been employed for facial rejuvenation purposes. However, to the best of our knowledge, no study has objectively assessed periorbital neoformation and remodeling of local cutaneous collagen, in a split-face model, from skin samples obtained during upper blepharoplasty.

OBJECTIVES

The authors sought to objectively evaluate neoformation and remodeling of local cutaneous collagen after periorbital skin fractional CO2 laser resurfacing.

METHODS

Sixteen female patients presenting with dermatochalasis and periorbital rhytids were evaluated in a prospective and comparative study. All patients underwent unilateral periorbital fractional CO2 laser resurfacing 30 days before upper blepharoplasty. Quantification of types I and III collagen from laser-treated and untreated eyelid skin samples obtained during upper blepharoplasty was assessed with histochemical analysis (Picrosirius Red staining). Laser resurfacing treatment was applied to the untreated side immediately after the upper blepharoplasty. Two blinded, independent physicians evaluated clinical improvement in pretreatment and 1- and 6-month posttreatment digital images.

RESULTS

Histochemical analysis showed significantly higher intensity in collagen types I (treated: 158.7 ± 5.3, untreated: 139.2 ± 5.0; P < 0.0001) and III (treated: 105.1 ± 7.7, untreated: 104.1 ± 7.1; P < 0.0001) in the fractional CO2 laser treatment samples; a greater difference was detected in collagen type I. A significant improvement in periorbital rhytidosis was observed 1 month after laser resurfacing (23%); a greater improvement in the periorbital region was observed 6 months after laser resurfacing and upper blepharoplasty (43.67%).

CONCLUSIONS

Periorbital fractional CO2 laser resurfacing was an effective method to improve palpebral skin, with histochemical evidence of increase in collagen types I and III.

LEVEL OF EVIDENCE: 4

Antifungal Activity of ToAP2D Peptide Against Sporothrix globosa

Improving clinical efficacy and reducing treatment time have been the focus of sporotrichosis therapy. Antimicrobial peptides ToAP2A, ToAP2C, and ToAP2D were synthesized on the basis of ToAP2 (AP02759), a peptide derived from the antimicrobial peptide database by the database filtering technology, and their physicochemical characteristics were analyzed. Compared with template peptide ToAP2, the modified peptides had much shorter length, lower molecular weight but significantly greater stability, which in return resulted in increases in the aliphatic index, hydrophilicity, and protein binding ability. Here, we show that the three derived peptides inhibit the growth of Sporothrix globosa, among which ToAP2D had the strongest anti-fungal activity. ToAP2D showed good serum stability without acute toxicity. The ToAP2D treatment inhibited the growth of S. globosa and enhanced apoptosis, which was evidenced by the upregulation of apoptosis-related protein caspase-3. The scanning electron microscopy analysis revealed deformation and rupture of S. globosa. The levels of mitochondrial membrane potential were decreased and that of the reactive oxygen species (ROS) were increased in S. globosa upon ToAP2D treatment. Moreover, ToAP2D activated metacaspase. In the in vivo study, we further demonstrated that ToAP2D inhibited the S. globosa infection of mice footpads, and its efficiency was nearly comparable to itraconazole. In summary, our results suggest that antimicrobial peptide ToAP2D has the potential for sporotrichosis therapy.

Efficacy of combined treatment with intense pulsed light and fractional erbium:YAG Laser in scar prevention: A randomized split wound trial

Various methods have been used for scar prevention; however, the optimal method remains unclear. We investigated the efficacy of combinational intense pulsed light (IPL)/fractional erbium-doped yttrium aluminum garnet (Er:YAG) laser treatment in early wound healing. This was a prospective, randomized, controlled split wound trial. Scars were divided into three sites: the combined IPL/fractional Er:YAG treatment, fractional Er:YAG laser treatment, and untreated control sites. Treatment was conducted in three sessions: at removal of stitches and after 4 and 8 weeks. Treatment efficacy was evaluated using the Patient Observer Scar Assessment Scale (POSAS) and Vancouver Scar Scale (VSS) scores. The erythema index (EI) and melanin index (MI) were measured. In the total POSAS score, the IPL/fractional Er:YAG site showed steady and significant improvement, in contrast to the other sites. At week 8, the combined treatment sites had better POSAS scores than the fractional Er:YAG laser alone sites (p = 0.001) and the control sites (p = 0.000). The effect of combinational treatment was maintained until the follow-up period by comparing the Er:YAG (p = 0.015) and control sites (p = 0.007). In terms of VSS scores, the IPL/fractional Er:YAG combined treatment sites had consistent improvement at week 8 (p = 0.005) and week 20 (p = 0.02) compared to that at week 4, while the other sites showed no such improvement. In conclusion, the combination of IPL and Er:YAG showed more favorable effects on scar prevention than Er:YAG or no treatment. IPL/Er:YAG therapy could be an effective and safe strategy in the early wound healing process for reducing scar formation.

Assessment of clinical efficacy of lidocaine/tetracaine 7%/7% peel cream in fractional microablative laser procedure-associated pain for facial skin aging treatment. A randomized, controlled, single-blind trial

BACKGROUND

Lidocaine/tetracaine 7%/7% peel cream (L/T-pC) is very effective in reducing pain in several dermatological procedures, such as hair or tattoo laser removal or conventional photodynamic therapy associated pain. Fractional laser resurfacing (FLR) is an effective treatment strategy for facial skin aging. The main drawback of FLR is the procedure-associated pain. So far, no controlled data are available regarding the efficacy of L/T-pC in reducing pain during a full-facial microablative FLR session in subjects with facial skin aging.

AIM

To assess the clinical efficacy of L/T-pC in reducing pain during microablative FLR treatment in subjects with facial skin aging. We conducted a prospective, randomized, parallel-group, controlled, single-blind trial, performed in out-patients attending to a Laser Clinic for facial skin aging treatment.

SUBJECTS AND METHODS

A total of 30 subjects (4 men, 26 women; mean age 42 ± 10 years; range 28-57) with mild to moderate facial skin aging (Glogau score ≥2), suitable for FLR treatment, were enrolled after their written informed consent. Participants were randomized to L/T-pC application (45 min before the laser treatment with the removal of the cream just before the starting of laser session) (n = 20) or to control (emollient cream; n = 10). FLR was performing using a fractional microablative CO₂ laser (Smartxide DOT 2 Deka) using a pulse power of 18 W (range 15-20) and pulse duration of 1.5 msec. The primary endpoint was the comparison of the mean visual analogue score (VAS) values between the two groups using a 10-cm scale (0 = no pain; 10: the most severe pain). The VAS score was measured just after the FLR session. Effective anesthesia (percentage of subjects with a VAS score ≤3) and the assessment of local tolerability and safety of the peel cream were the secondary trial endpoints.

RESULTS

All the enrolled subjects concluded the trial. In the L/T-pC group, the VAS mean score was 3.0 ± 1.2. In the control group, the VAS mean score was 8.6 ± 0.5, representing a 65% reduction of the VAS score in the active treated group vs. controls. The difference between the two groups was statistically significant (p = 0.0001; Mann-Whitney test) with an absolute difference of -5 ± 0.4 cm; 95%CI of the difference: from -4.6 to -6.4 cm). Adequate anesthesia (VAS score≤3) was reported in 80% of subjects in the active group vs. 0% in the control arm. The cream was very well tolerated. One subject in the active group manifested moderate/severe edema in the cream application area, subsiding in 6 h. No other side effects were reported.

CONCLUSION

The application of L/T pC 7%/7% peel cream before a fractional laser resurfacing session significantly reduced the procedure-associated pain with good tolerability and safety profile.

Laser Resurfacing for the Management of Periorbital Scarring

Laser (light amplification by the stimulated emission of radiation) skin resurfacing is currently one of the most widely adopted technologies in facial rejuvenation. While most often used for aesthetic purposes, lasers also have applications in the management of scars. Since the introduction of the CO₂ laser for skin rejuvenation in the 1990s, the last three decades have seen significant growth in the number of laser devices available to the physician. More recently, promising alternatives to light-based resurfacing technologies have emerged that include radiofrequency and intense focused ultrasound. To help the physician navigate the most current laser technologies as they apply to periocular scars, this review discusses the available treatment modalities, pre-treatment assessment of periorbital scars, treatment selection, and reported outcomes and complications. The recommendations described herein are based on published literature and the authors' experience in an academic oculoplastics practice.

Ablative Fractional Carbon Dioxide Laser and Autologous Platelet-Rich Plasma in the Treatment of Atrophic Acne Scars: A Comparative Clinico-Immuno-Histopathological Study

BACKGROUND AND OBJECTIVES

To compare the efficacy of autologous platelet-rich plasma (PRP), ablative fractional carbon dioxide (FCO₂ ) laser, and their combination in the treatment of atrophic acne scars, both clinically and immuno-histopathologically.

STUDY DESIGN/MATERIALS AND METHODS

Sixty patients were randomly divided into three equal groups. Group 1 received intradermal PRP injection sessions. Group 2 received FCO₂ laser sessions. Group 3 received FCO₂ laser followed by intradermal PRP injection sessions. Each group received three sessions at monthly intervals. The final assessment took place 3 months after the last session. Skin biopsies were obtained before and 1 month after treatment sessions with pathological evaluation.

RESULTS

Combined PRP and FCO₂ laser-treated patients had a better clinical response, fewer side effects, and shorter downtime than FCO₂ laser alone. PRP-treated patients had some improvement but significantly lower than the other two groups.

CONCLUSION

The current study concluded that a combination of PRP and FCO₂ laser is an effective and safe modality in the treatment of atrophic acne scars with better results than PRP or FCO₂ laser alone. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Laser pretreatment for the attenuation of planned surgical scars: A randomized self-controlled hemi-scar pilot study

BACKGROUND

Nonsurgical scar attenuation options include compression garments, silicone gel, intralesional drug therapy, radiation therapy, laser, and light therapies. Laser application preceding surgical intervention has been shown to modify the wound-healing process and affect subsequent scar formation. The objective of this study was to evaluate the safety, efficacy, and final cosmesis of a single presurgical laser treatment on surgical scar formation.

METHODS

This was a randomized, controlled, intraindividual split-scar pilot study with blinded assessments of treated versus untreated planned incision sites. One half of each planned scar was treated by means of an Erbium glass, 1540 nm laser, 24 h before surgery, and the other half was not treated and served as the control. Clinical evaluations and the measurements of patient and physician POSAS scales were done at 1 and 12 months following surgery.

RESULTS

Eleven patients completed the study and were included in the analyses. Laser pretreatment showed a significant beneficial effect compared with no treatment. Both the patient and physician mean Patient and Observer Scar Assessment Scale scores were significantly lower for the laser-treated half of the scars compared with the control side (1.55 to 3.00, p = 0.02 and 2.28 to 4.42, p = 0.03). There was a highly significant interobserver correlation in the evaluation of the overall posttreatment changes (r = 0.904, p < 0.001).

CONCLUSION

A single presurgical laser treatment of a planned incision site is a simple, safe, and painless strategy to significantly improve the final scar appearance.

Fractional 1,927 nm Thulium Laser Plus Photodynamic Therapy Compared and Combined for Photodamaged Décolleté Skin: A Side-by-Side Randomized Controlled Trial

BACKGROUND AND OBJECTIVES

Décolleté photodamage is a common condition typically treated with light and energy-based devices. This study investigated the efficacy and safety of a fractional 1,927 nm thulium laser (TL) alone and combined with photodynamic therapy (PDT).

STUDY DESIGN/MATERIALS AND METHODS

In a 12-week follow-up study, participant décolletés were divided into four treatment areas and randomized to receive a single treatment with field-directed TL, PDT, combination TL-PDT, or lesion-directed curettage control. All actinic keratoses (AKs) underwent lesion-directed curettage before randomization. TL was delivered at 20 mJ/mb, 500 mJ/cm² fluence, 5 W, and 8 (n = 6 pts.) or 16 (n = 6 pts.) passes. PDT was performed with 16% methyl aminolevulinate (MAL) creme incubated for 3 h, followed by red light-emitting diode light at 37 J/cm² . Outcome measures included clinical assessment of overall photodamage and specific subcomponents, assisted by optical coherence tomography (OCT) imaging.

RESULTS

Twelve women with moderate to severe photodamage on the décolleté and a cumulative total of 184 thin grade I AKs were included. Field-directed treatments TL and combination TL-PDT equally improved the overall photodamage, mottled pigmentation, and rhytides compared with lesion-directed control (P < 0.05). The skin texture improved by TL alone and was further improved by combining TL and PDT (P < 0.05). Median AK complete responses were similar for field-directed interventions TL-PDT (100%), TL (90%), PDT (82%), and lesion-directed curettage control (52%) (P = 0.464). Patients presented with mild local skin responses, slightly more pronounced when combining TL with PDT versus individual treatments (P < 0.05). No scarring or adverse events were observed.

CONCLUSIONS

The 1,927 nm fractional thulium laser is an effective, tolerable, and safe field-directed treatment for décolleté photodamage. Provided alone, TL proved to be as effective as combined TL-PDT for overall photodamage, while a greater improvement in skin texture was achieved using TL and PDT in combination. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

When Wounds Are Good for You: The Regenerative Capacity of Fractional Resurfacing and Potential Utility in Chronic Wound Prevention

Significance: Fractional resurfacing involves producing arrays of microinjuries on the skin, by thermal or mechanical means, to trigger tissue regeneration. Originally developed for cosmetic enhancement, fractional resurfacing induces a broad array of improvements in the structural and functional qualities of the treated skin and is especially effective at returning defective skin to a more normal state. In addition to fascinating questions about the nature of this remarkable regenerative capacity, there may be potential utility in ulcer prevention by halting or even reversing the progressive decline in overall skin quality that usually precedes chronic wound development. Recent Advances: Photoaging and scarring are the two skin defects most commonly treated by fractional resurfacing, and the treatment produces profound and long-lasting improvements in skin quality, both clinically and at the cellular/histologic level. Chronic wounds usually occur in skin that is compromised by various pathologic factors, and many of the defects found in this ulcer-prone skin are similar to those that have seen improvements after fractional resurfacing. Critical Issues: The mechanisms responsible for the regenerative capacity of fractional resurfacing are mostly unknown, as is how ulcer-prone skin, which is usually afflicted by stressors external to the skin tissue itself, would respond to fractional resurfacing. Future Directions: Better understanding of the cellular and molecular mechanisms underlying the unique healing response to fractional resurfacing could reveal fundamental information about adult tissue regeneration, lead to improvements in current applications, as well as new therapies in other pathologic conditions.

The Treatment of Acne Scars, a 30-Year Journey

Over the past 30 years, the treatment of acne scars has undergone changes that have been significantly influenced by the concurrent development of new devices. The advent of fractional resurfacing lasers was a watershed moment for acne scarring therapy. The author recounts a career history of considerations of acne scarring treatments as well as the literature supporting the experiences causing changes in practice. Fractional ablative and nonablative lasers, sublative radiofrequency, picosecond lasers, microneedling with and without radiofrequency and fillers are the bulk of the treatments covered, along with a discussion of combination therapy. A practical algorithm for acne scarring for selection of treatment modalities is presented.

A dose-response study of a novel method of selective tissue modification of cellular structures in the skin with nanosecond pulsed electric fields

Background and Objectives

This study describes the effects of nanosecond pulsed electric fields (nsPEF) on the epidermis and dermis of normal skin scheduled for excision in a subsequent abdominoplasty. NsPEF therapy applies nanosecond pulses of electrical energy to induce regulated cell death (RCD) in cellular structures, with negligible thermal effects. Prior pre‐clinical studies using nsPEF technology have demonstrated the ability to stimulate a lasting immune response in animal tumor models, including melanoma. This first‐in‐human‐use of nsPEF treatment in a controlled study to evaluate the dose‐response effects on normal skin and subcutaneous structures is intended to establish a safe dose range of energies prior to use in clinical applications using nsPEF for non‐thermal tissue modification.

Study Design/Materials and Methods

Seven subjects with healthy tissue planned for abdominoplasty excision were enrolled. Five subjects were evaluated in a longitudinal, 60‐day study of effects with doses of six nsPEF energy levels. A total of 30 squares of spot sizes 25mm² or less within the planned excision area were treated and then evaluated at 1 day, 5 days, 15 days, 30 days, and 60 days prior to surgery. Photographs were taken over time of each treated area and assessed by three independent and blinded dermatologists for erythema, flaking and crusting using a 5‐point scale (0 = low, 4 = high). Punch biopsies of surgically removed tissue were processed and evaluated for tissue changes using hematoxylin and eosin, trichome, caspase‐3, microphthalmia transcription factor, and elastin stains and evaluated by a dermatopathologist. The skin of two subjects received additional treatments at 2 and 4 hours post‐nsPEF and was evaluated in a similar manner.

Results

Most energy settings exhibited delayed epidermal loss followed by re‐epithelization by day 15 and a normal course of healing. Histologic analysis identified the appearance of activated caspase‐3 at two and four hours after nsPEF treatment, but not at later time points. At the 1‐day time point, a nucleolysis effect was observed in epidermal cells, as evidenced by the lack of nuclear staining while the epidermal plasma membranes were still intact. Cellular structures within the treatment zone such as melanocytes, sebaceous glands, and hair follicles were damaged while acellular structures such as elastic fibers and collagen were largely unaffected except for TL6 which showed signs of dermal damage. Melanocytes reappeared at levels comparable with untreated controls within 1 month of nsPEF treatment.

Conclusions

The selective effect of nsPEF treatment on cellular structures in the epidermal and dermal layers suggests that this non‐thermal mechanism for targeting cellular structures does not affect the integrity of dermal tissue within a range of energy levels. The specificity of effects and a favorable healing response makes nsPEF ideal for treating cellular targets in the epidermal or dermal layers of the skin, including treatment of benign and malignant lesions. NsPEF skin treatments provide a promising, non‐thermal method for treating skin conditions and removing epidermal lesions. © 2019 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

Early fractional carbon dioxide laser intervention for postsurgical scars in skin of color

Background

Fractional CO₂ laser is one of the most effective treatment options used to resurface scars.

Objective

To evaluate the efficacy and safety of early treatment of postsurgical scar by fractional ablative CO₂ laser.

Methods

A total of 27 Egyptian patients with recent postoperative scars were enrolled in this study. Three sessions of fractional CO₂ laser with a 1-month interval were started 4 weeks after surgery. Vancouver Scar Scale (VSS) was used as an assessment tool at 1 and 3 months after the final treatment. Patients reported their satisfaction using a subjective 4-point scale.

Results

Results demonstrated a statistically significant overall average improvement of the VSS (5.33±1.33) before compared with (2.55±1.06) 3 months after the last laser treatment (P≤0.001). Among the individual parameters in the VSS, the most significant improvements were found in pigmentation, height, and pliability. Patient's subjective satisfaction scores showed a significant greater degree of satisfaction after laser treatment.

Conclusion

Fractional ablative CO₂ laser is an effective and safe treatment modality for surgical scars in the early postsurgical period.

Treatment to External Labia and Vaginal Canal With CO2 Laser for Symptoms of Vulvovaginal Atrophy in Postmenopausal Women

Background

Increasingly, women have sought alternatives to traditional options (lubricants, estrogen products, and hormone replacement therapy) for unwelcome vaginal changes of menopause.

Objectives

This study evaluated whether a series of three monthly fractional CO₂ laser treatments significantly improves and maintains vaginal health indices of elasticity, fluid volume, pH level, epithelial integrity, and moisture. Self-reported symptoms of vaginal atrophy were also measured. Biopsy samples after a series of three treatments were evaluated for histological changes to vaginal canal tissue.

Methods

Forty postmenopausal women were treated extravaginally and internally with a fractional CO₂ laser. Objective measurements of vaginal health index, as well as subjective measurements of symptoms of vulvovaginal atrophy (VVA), urinary incontinence, and sexual function were reported at baseline. Follow-up evaluations were at one, three, six, and 12 months after the third treatment.

Results

Vaginal health index improved significantly after the first treatment and was maintained with mean improvement of 9.6 ± 3.3 (P < 0.001) and 9.5 ± 3.3 (P < 0.001) at the 6- and 12-month follow ups, respectively. Vaginal symptoms of dryness, itching, and dyspareunia improved significantly (P < 0.05) at all evaluations. Histological findings showed increased collagen and elastin staining, as well as a thicker epithelium with an increased number of cell layers and a better degree of surface maturation.

Conclusions

Fractional CO₂ laser treatments were well tolerated and were associated with improvement in vaginal health and amelioration of symptoms of VVA. Histological changes in the epithelium and lamina propria, caused by fractional CO₂ laser treatments, correlated with clinical restoration of vaginal hydration and pH to premenopausal levels.

Level of Evidence: 4

Early laser intervention to reduce scar formation - a systematic review

The ability of laser treatment to affect wound healing and subsequently minimize scar formation has been investigated in recent years. However, no systematic review links these clinical trials. The aim of this study was to systematically review and evaluate clinical evidence for early laser intervention to reduce scar formation in studies where laser treatment was introduced less than 3 months after wounding. We searched PubMed using relevant keywords in June 2017. Titles, abstracts and articles were sorted according to inclusion and exclusion criteria. Methodological quality was evaluated according to Cochrane Collaborations risk-of-bias assessment guideline by two independent authors. Twenty-five articles met the inclusion criteria. In total, 22 of 25 studies were controlled studies, and 17 of 25 studies compared laser treatment vs. untreated control scars. The following laser devices have been investigated: pulsed dye laser (PDL), potassium-titanyl-phosphate (KTP) laser, fractional erbium:glass 1540 nm/1550 nm, fractional/full ablation erbium-doped yttrium aluminium garnet (Er:YAG) laser or fractional CO2 laser. Eighteen studies applied laser treatments 2-4 times with 2- to 8-week intervals, while seven studies applied only one laser treatment. Follow-up time ranged from 1 to 12 months with 18 studies using a follow-up time ≤3 months. In general, laser-treated wounds and scars showed benefit from laser intervention, though not always reaching significance. Significant scar improvement was found in three of four studies using laser treatment in inflammation phase, in six of 16 studies with laser initiated in the proliferation phase and in two of five studies in the remodelling phase. High risk of bias was found in randomization and allocation concealment, and low risk of bias with regard to blinding of outcome assessment and lost to follow-up. In conclusion, laser intervention when introduced in inflammation, proliferation or remodelling phase has the potential to reduce cutaneous scar formation. Further, high-quality studies are needed before standard protocols can be implemented in clinical practice.

Prediction of Treatment Outcomes for Neck Rejuvenation Utilizing a Unique Classification System of Treatment Approach Using a 1440-nm Side-Firing Laser

BACKGROUND

The appearance of a youthful neck is lost with age causing excessive skin laxity, a loss of subcutaneous fat, prominence of platysmal banding, and jowling. In view of the success obtained with laser treatment for neck rejuvenation, the authors have recently taken an algorithmic approach to developing a 7-category classification system of the aging conditions throughout the anatomic spectrum of three areas: skin, fat, and muscle. This system will correlate with specific treatment options.

OBJECTIVE

The objective of the study was to confirm the 7-category classification system and treatment approaches based on clinical outcome data for treatment of the mandibular and submandibular areas, specifically for skin tightening and laser lipolysis after a single 1440-nm laser treatment.

METHODS

Patients were treated with a single treatment of PrecisionTX™ 1440-nm wavelength laser on their necks. Baseline and posttreatment photographs were taken and evaluated by 3 blinded reviewers using the Cervicomental Angle Scale (CAS).

RESULTS

Subjects were rated grades II-III (2.9 ± 0.8) on average at baseline and grades I-II (1.3 ± 0.5) at follow-up. The average improvement was a mean score of 1.5 ± 0.07. Patients, 23/25 (92%), showed at least a 1 score improvement.

CONCLUSIONS

This study confirms a new minimally invasive treatment approach based on a unique classification system with no adverse events reported and high patient satisfaction.

LEVEL OF EVIDENCE 4

Use of a novel fractional CO2 laser for the treatment of genitourinary syndrome of menopause: 1-year outcomes

OBJECTIVES

To assess safety and efficacy of a fractional CO2 laser therapy for the treatment of genitourinary syndrome of menopause (GSM) with follow-up to 1 year posttreatment.

METHODS

Women presenting with GSM and meeting inclusion criterion were enrolled. Visual Analog Scales were used to grade vaginal pain, burning, itching, dryness, dyspareunia, and dysuria. Dilators were used to rate vaginal elasticity at baseline and at each follow-up visit. Before each treatment and at follow-up, Vaginal Health Index scoring and Female Sexual Function Index questionnaires were completed. Women received three vaginal laser treatments spaced 6 weeks apart. Participant satisfaction was measured on 5-point Likert scales (1 = very dissatisfied, 5 = very satisfied).

RESULTS

Of 30 women (mean age 58.6 ± 8.8 years), three were lost to follow-up at 3 months and six at 1 year. None were discontinued or withdrew due to an adverse event. Average improvement in Visual Analog Scale scores for all symptom categories was statistically significant at 3 months and remained so through 1 year, except dysuria. Differences between data at 3 months and 1 year were not statistically significant, indicating persistence of positive outcomes. Average overall improvement in pain was 1.9 (±3.4), burning 1.9 (±3.1), itching 1.4 (±1.9), dryness 5.9 (±2.8), dyspareunia 4.9 (±3.3), and dysuria 0.9 (±3.1). Improvement in average Vaginal Health Index and Female Sexual Function Index scores was also statistically significant (P < 0.0001). Of 19 women undergoing dilator examination at 1 year, 18 (94.8%) were comfortable with the same or larger dilator size. Twenty-two of 24 women (92%) were satisfied or extremely satisfied with the treatment at 1 year.

CONCLUSIONS

Based on study data up to 1 year, the fractional CO2 laser may be an effective and safe treatment for women suffering from symptoms of GSM, although additional studies with larger populations and placebo control is needed to confirm these results.

Endoscopic non-ablative fractional laser therapy in an orthotopic colon tumour model

Colorectal cancer is one of the leading causes of cancer-related deaths. Although several therapeutic management strategies are available at the early colon cancer stages, such as endoscopic mucosal or submucosal dissection, associated complications often include bleeding or bowel perforations. As an alternative approach, we investigated endoscopic non-ablative fractional laser (eNAFL) irradiation as a minimally invasive therapeutic modality for the treatment of early-stage colorectal cancer. By implanting SL4-DsRed colon cancer cells into the colons of the C57BL/6 mice, we developed an orthotopic colon tumour mouse model and demonstrated the early-stage tumour growth delay following the eNAFL irradiation. Additionally, we evaluated the temperature changes in the eNAFL-irradiated area using numerical simulations, and induced inflammation using histological analysis. Our results indicate a minimal thermal damage confined to the irradiated spot, sparing the adjacent tissue and alteration in the tumour microenvironment. eNAFL irradiation may be clinically useful as a minimally invasive therapeutic intervention at the early stage of tumourigenesis. In future, an optimal eNAFL therapeutic dose should be determined, in order to increase the efficacy of this approach.

An assessment of the safety and efficacy of a fractional CO2 laser system for the treatment of vulvovaginal atrophy

OBJECTIVES

The aim of the study was to assess the safety and efficacy of a novel fractional CO2 laser for the treatment of genitourinary syndrome of menopause (GSM).

METHODS

Women presenting with GSM and meeting study criteria were enrolled. Examinations at baseline and follow-up (3 mo after final treatment) evaluated dilator tolerance and vaginal pH. Visual analog scales were used to assess pain, vaginal burning, vaginal itching, vaginal dryness, dyspareunia, and dysuria; Vaginal Health Index scores were completed before each treatment and at follow-up; Female Sexual Function Index and Short Form 12 questionnaires were also completed. Participant satisfaction was measured on a 5-point Likert scale (1 = very dissatisfied, 5 = very satisfied). Women received three laser treatments, 6 weeks apart.

RESULTS

Thirty women participated (mean age 58.6 ± 8.8 y). None withdrew or were discontinued due to an adverse event; three were lost to follow-up. Average improvement in visual analog scale scoring was 1.7 ± 3.2 for pain, 1.4 ± 2.9 for burning, 1.4 ± 1.9 for itching, 6.1 ± 2.7 for dryness, 5.1 ± 3.0 for dyspareunia, and 1.0 ± 2.4 for dysuria; improvement in average Vaginal Health Index and Female Sexual Function Index scores were statistically significant (P < 0.001). Twenty-five of 30 participants (83%) showed increase in comfortable dilator size at 3-month follow up. Before the second and third treatments, 86.6% (26 of 30) of women reported they were better or much better than at the previous treatment; 26 of 27 women (96%) were reportedly satisfied or extremely satisfied at follow-up.

CONCLUSIONS

In this sample, the data suggest that the fractional CO2 laser is effective and safe for treatment of the symptoms associated with GSM.

Molecular effects of fractional ablative erbium:YAG laser treatment with multiple stacked pulses on standardized human three-dimensional organotypic skin models

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.

Method for Picrosirius Red-Polarization Detection of Collagen Fibers in Tissue Sections

The extracellular matrix is critical in guiding cell behavior in normal and pathologic tissues, particularly in cancers and fibrosis. Highlighting the organization (or disorganization) of a collagen-containing matrix can be very useful for understanding or grading pathophysiological conditions. The picrosirius red stain (also called "Sirius red" stain) is one of the best understood histochemical techniques able to selectively highlight collagen networks. Relatively inexpensive, the technique relies on the birefringent properties of collagen molecules. While the picrosirius red stain alone does not selectively bind collagen network, it becomes more specific than the other common collagen stains when combined with polarized light detection. This is why the selective histochemical procedure for collagen detection should be called the picrosirius-polarization method. In this chapter, we will provide essential explanation and detailed protocols and tips to allow collagen researchers not only to better understand how this staining technique works but also to easily apply this technique to their collagen-related research.

Scar Management in the Pediatric and Adolescent Populations

For most children and adolescents who have developed symptomatic scars, cosmetic concerns are only a portion of the motivation that drives them and their caregivers to obtain treatment. In addition to the potential for cosmetic disfigurement, scars may be associated with a number of physical comorbidities including hypertrichosis, dyshidrosis, tenderness/pain, pruritus, dysesthesias, and functional impairments such as contractures, all of which may be compounded by psychosocial factors. Although a plethora of options for treating scars exists, specific management guidelines for the pediatric and adolescent populations do not, and evidence must be extrapolated from adult studies. New modalities such as the scar team approach, autologous fat transfer, and ablative fractional laser resurfacing suggest a promising future for children who suffer symptomatically from their scars. In this state-of-the-art review, we summarize cutting-edge scar treatment strategies as they relate to the pediatric and adolescent populations.

Effects of non-ablative fractional erbium glass laser treatment on gene regulation in human three-dimensional skin models

Clinical experiences with non-ablative fractional erbium glass laser therapy have demonstrated promising results for dermal remodelling and for the indications of striae, surgical scars and acne scars. So far, molecular effects on human skin following treatment with these laser systems have not been elucidated. Our aim was to investigate laser-induced effects on skin morphology and to analyse molecular effects on gene regulation. Therefore, human three-dimensional (3D) organotypic skin models were irradiated with non-ablative fractional erbium glass laser systems enabling qRT-PCR, microarray and histological studies at same and different time points. A decreased mRNA expression of matrix metalloproteinases (MMPs) 3 and 9 was observed 3 days after treatment. MMP3 also remained downregulated on protein level, whereas the expression of other MMPs like MMP9 was recovered or even upregulated 5 days after irradiation. Inflammatory gene regulatory responses measured by the expression of chemokine (C-X-C motif) ligands (CXCL1, 2, 5, 6) and interleukin expression (IL8) were predominantly reduced. Epidermal differentiation markers such as loricrin, filaggrin-1 and filaggrin-2 were upregulated by both tested laser optics, indicating a potential epidermal involvement. These effects were also shown on protein level in the immunofluorescence analysis. This novel standardised laser-treated human 3D skin model proves useful for monitoring time-dependent ex vivo effects of various laser systems on gene expression and human skin morphology. Our study reveals erbium glass laser-induced regulations of MMP and interleukin expression. We speculate that these alterations on gene expression level could play a role for dermal remodelling, anti-inflammatory effects and increased epidermal differentiation. Our finding may have implications for further understanding of the molecular mechanism of erbium glass laser-induced effects on human skin.

Fractional Erbium laser in the treatment of photoaging: randomized comparative, clinical and histopathological study of ablative (2940nm) vs. non-ablative (1540nm) methods after 3 months

BACKGROUND

Fractional non-ablative lasers keep the epidermis intact, while fractional ablative lasers remove it, making them theoretically more effective.

OBJECTIVES

To evaluate the clinical and histological alterations induced by fractional photothermolysis for treating photoaging, comparing the possible equivalence of multiple sessions of 1540nm Erbium, to one session of 2940nm Erbium.

METHODS

Eighteen patients (mean age 55.9) completed the treatment with three sessions of 1540nm fractional Erbium laser on one side of the face (50 mJ/mB, 15ms, 2 passes), and one session of 2940nm on the other side (5mJ/mB, 0.25ms, 2 passes). Biopsies were performed before and 3 months after treatment. Clinical, histological and morphometric evaluations were carried out.

RESULTS

All patients presented clinical improvement with no statistically significant difference (p> 0.05) between the treated sides. Histopathology revealed a new organization of collagen and elastic fibers, accompanied by edema, which was more evident with the 2940nm laser. This finding was confirmed by morphometry, which showed a decrease in collagen density for both treatments, with a statistical significance for the 2940nm laser (p > 0.001).

CONCLUSIONS

Three 1540nm sessions were clinically equivalent to one 2940nm session. The edema probably contributed to the positive results after three months, togheter with the new collagen and elastic fibers organization. The greater edema after the 2940nm session indicates that dermal remodeling takes longer than with 1540nm. It is possible that this histological superiority relates to a more prolonged effect, but a cohort longer than three months is needed to confirm that supposition.

Treatment of cosmetic tattoos with nonablative fractional laser in an animal model: a novel method with histopathologic evidence

BACKGROUND AND OBJECTIVE

Cosmetic tattoos are difficult to treat using Q-switched lasers. We introduce a novel method for the treatment of cosmetic tattoos using a nonablative fractional laser and investigate the underlying pathophysiological mechanisms in an animal model.

STUDY DESIGN/MATERIALS AND METHODS

Ten rats were tattooed on their backs with white and flesh-colored pigments. One-half of each tattoo was treated with a 1,550-nm, erbium:glass fractional laser system with energy settings of 17 mJ and 169 MTZ/cm(2)  × 2 passes for five sessions at 1-month intervals. The untreated half of each tattoo served as the control. An independent physician reviewed the photographs and scored the clinical response. Serial skin samples were obtained at baseline and at various times after laser treatment. These tissue sections were stained with hematoxylin and eosin, and immunostained for types I, III, and IV collagen; laminin; fibronectin; and α-smooth muscle actin.

RESULTS

White tattoos showed excellent responses in two rats and good responses in eight rats, whereas flesh-colored tattoos showed excellent responses in four rats and good responses in six rats (P = 0.001 in both cases compared with baseline). Both tattoos exhibited a similar clearance rate (P > 0.05) and histological reactions. Microscopic epidermal necrotic debris (MEND) containing tattoo pigments and collagen fibrils appeared on day 1, increased on day 2, and was exfoliated after 5 days. The dermal-epidermal junction lost integrity 30 minutes after treatment, but recovered completely on day 3. The expression of fibronectin and collagen-III, which play key roles in wound healing, increased around the microscopic treatment zone on days 1-5 and 4-7, respectively. A few myofibroblasts appeared on days 4-7.

CONCLUSION

Nonablative fractional lasers (NAFLs) successfully remove cosmetic tattoos by transepidermal elimination of tattoo pigments through the disrupted dermal-epidermal junction. This action is facilitated by the wound healing process.

Fractional versus ablative erbium:yttrium-aluminum-garnet laser resurfacing for facial rejuvenation: an objective evaluation

BACKGROUND

Laser is one of the main tools for skin resurfacing. Erbium:yttrium-aluminum-garnet (Er:YAG) was the second ablative laser, after carbon dioxide, emitting wavelength of 2940 nm. Fractional laser resurfacing has been developed to overcome the drawbacks of ablative lasers.

OBJECTIVE

We aimed to objectively evaluate the histopathological and immunohistochemical effects of Er:YAG 2940-nm laser for facial rejuvenation (multiple sessions of fractional vs single session of ablative Er:YAG laser).

METHODS

Facial resurfacing with single-session ablative Er:YAG laser was performed on 6 volunteers. Another 6 were resurfaced using fractional Er:YAG laser (4 sessions). Histopathological (hematoxylin-eosin, orcein, Masson trichrome, and picrosirius red stains) and immunohistochemical assessment for skin biopsy specimens were done before laser resurfacing and after 1 and 6 months. Histometry for epidermal thickness and quantitative assessment for neocollagen formation; collagen I, III, and VII; elastin; and tropoelastin were done for all skin biopsy specimens.

RESULTS

Both lasers resulted in increased epidermal thickness. Dermal collagen showed increased neocollagen formation with increased concentration of collagen types I, III, and VII. Dermal elastic tissue studies revealed decreased elastin whereas tropoelastin concentration increased after laser resurfacing. Neither laser showed significant difference between their effects clinically and on dermal collagen. Changes in epidermal thickness, elastin, and tropoelastin were significantly more marked after ablative laser.

LIMITATIONS

The small number of patients is a limitation, yet the results show significant improvement.

CONCLUSION

Multiple sessions of fractional laser have comparable effects to a single session of ablative Er:YAG laser on dermal collagen but ablative laser has more effect on elastic tissue and epidermis.

Recent Advances in Fractional Laser Resurfacing: New Paradigm in Optimal Parameters and Post-Treatment Wound Care

BACKGROUND

Laser plays an increasingly prominent role in skin rejuvenation. The advent of fractional photothermolysis revolutionizes its application. Microcolumns of skin are focally injured, leaving intervening normal skin to facilitate rapid wound healing and orderly tissue remodeling.

THE PROBLEM

Even with the popularity of fractional laser devices, we still have limited knowledge about the ideal treatment parameters and postlaser wound care.

BASIC/CLINICAL SCIENCE ADVANCES

Many clinicians believe that higher microbream energy in fractional laser devices results in better clinical outcome. Two recent studies argue against this assumption. One article demonstrates that lower fluence can induce comparable molecular changes with fewer side effects. Another study corroborates this by showing that lower-density settings produce similar clinical outcome in scar remodeling as higher-density ones, but with fewer side effects. To shed light on the optimal post-treatment wound care regimen from fractional ablative resurfacing, another paper shows that platelet-rich plasma (PRP) can reduce transepidermal water loss and skin color changes within 1 month after treatment.

CLINICAL CARE RELEVANCE

For fractional nonablative resurfacing, lower settings in fluence or density may produce similar dermal remodeling as higher settings and with a better side-effect profile. Moreover, autologous PRP appears to expedite wound healing after fractional ablative resurfacing.

CONCLUSION

Lower microbeam energy in fractional laser resurfacing produces similar molecular changes and clinical outcome with fewer side effects. The findings might portend a shift in the paradigm of treatment parameters. Autologous PRP can facilitate better wound healing, albeit modestly. Long-term follow-ups and larger studies are necessary to confirm these findings.