Fractional CO(2) laser-assisted drug delivery

Laser-assisted topical delivery of vismodegib reduces hedgehog gene expression in human basal cell carcinomas in vivo

BACKGROUND

Systemically delivered hedgehog inhibitors including vismodegib and sonidegib are widely used to treat basal cell carcinomas (BCCs). Ablative fractional laser (AFL)-assisted topical delivery of vismodegib has been demonstrated in preclinical studies. The aim of this explorative clinical study was to evaluate intratumoral vismodegib concentrations and effect on hedgehog pathway gene expression following AFL-assisted topical vismodegib delivery to BCCs.

METHODS

In an open-label clinical trial, 16 nodular BCCs (in n = 9 patients) received one application of CO2 -AFL (40 mJ/microbeam, 10% density) followed by topical vismodegib emulsion. After 3-4 days, vismodegib concentrations in tumor biopsies (n = 15) and plasma were analyzed and compared with samples from patients receiving oral treatment (n = 3). GLI1, GLI2, PTCH1, and PTCH2 expression was determined by quantitative polymerase chain reaction (n = 7) and GLI1 additionally by in situ hybridization (n = 3).

RESULTS

Following AFL-assisted topical administration, vismodegib was detected in 14/15 BCCs and reached a median concentration of 6.2 µmol/L, which compared to concentrations in BCC tissue from patients receiving oral vismodegib (9.5 µmol/L, n = 3, p = 0.8588). Topical vismodegib reduced intratumoral GLI1 expression by 51%, GLI2 by 55%, PTCH1 and PTCH2 each by 73% (p ≤ 0.0304) regardless of vismodegib concentrations (p ≥ 0.3164). In situ hybridization demonstrated that GLI1 expression was restricted to tumor tissue and downregulated in response to vismodegib exposure.

CONCLUSION

A single AFL-assisted topical application of vismodegib resulted in clinically relevant intratumoral drug concentrations and significant reductions in hedgehog pathway gene expressions.

Novel 40 µm spot size 3050/3200 nm DFG laser versus CO2 laser for laser-assisted drug delivery

BACKGROUND AND OBJECTIVES

The use of ablative fractional lasers to enhance the delivery of topical drugs through the skin is known as laser-assisted drug delivery. Here, we compare a novel 3050/3200 nm difference frequency generation (DFG) fiber laser (spot size: 40 µm) to a commercially used CO2 laser (spot size: 120 µm). The objective is to determine whether differences in spot size and coagulation zone (CZ) thickness influence drug uptake.

MATERIALS AND METHODS

Fractional ablation was performed on ex-vivo human abdominal skin with the DFG (5 mJ) and CO2 (12 mJ) lasers to generate 680 µm deep lesions. To evaluate drug delivery, 30 kDa encapsulated fluorescent dye was topically applied to the skin and histologically analyzed at skin depths of 100, 140, 200, 400, and 600 µm. Additionally, transcutaneous permeation of encapsulated and 350 Da nonencapsulated dye was assessed using Franz Cells.

RESULTS

The DFG laser generated smaller channels (diameter: 56.5 µm) with thinner CZs (thickness: 22.4 µm) than the CO2 laser (diameter: 75.9 µm, thickness: 66.8 µm). The DFG laser treated group exhibited significantly higher encapsulated dye total fluorescence intensities after 3 h compared to the CO2 laser treated group across all skin depths (p < 0.001). Permeation of nonencapsulated dye was also higher in the DFG laser treated group vs the CO2 laser treated group after 48 h (p < 0.0001), while encapsulated dye was not detected in any group.

CONCLUSION

The DFG laser treated skin exhibited significantly higher total fluorescence uptake compared to the CO2 laser. Additionally, the smaller spot size and thinner CZ of the DFG laser could result in faster wound healing and reduced adverse effects while delivering similar or greater amount of topically applied drugs.

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 in vivo 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.

Does Platelet-Rich Plasma Promote Facial Rejuvenation? Revising the Latest Evidence in a Narrative Review

Facial aging is characterized by progressive macroscopic, histological, and molecular changes. Due to its regenerative and rejuvenating properties, the use of platelet-rich plasma (PRP) as a facial antiaging agent has gained popularity over the last decade. In order to gather and evaluate the latest evidence focusing on the effect of PRP on facial skin rejuvenating, a search through MEDLINE (PubMed) using relevant keywords, inclusion, and exclusion criteria was performed. A total of 539 articles were initially retrieved, and from those, 16 were included in the review. Treatment protocols comprised the use of PRP both in monotherapy and in combination with other substances and by means of direct injection or topical application following skin permeation. The selected studies presented high variability regarding PRP preparation methods, administration protocols, and results assessment. In most studies, PRP seemed to improve to some degree the signs of facial aging, such has wrinkles, skin quality, and pigmentation, accompanied by significant histological and molecular responses. Optimizing treatment protocols should be the next step in assessing the full potential of PRP.

Laser-Assisted and Device-Assisted Filler Delivery: A Histologic Evaluation

BACKGROUND

Lasers and devices are used to enhance transcutaneous delivery of fillers. However, little has been published on the histologic findings of this form of laser/device-assisted delivery to determine the optimal devices and fillers.

OBJECTIVE

To objectively evaluate the histological effects of laser-assisted and device-assisted filler delivery.

METHODS

Ex vivo human abdominoplasty skin samples were treated with fractional CO 2 laser (ECO 2 , 120 μm tip, 120 mJ), fractional radiofrequency microneedling (FRMN, Genius, 1.5 mm, 20 mJ/pin), and microneedling (2.0 mm). Immediately after poly- l -lactic acid (PLLA), hyaluronic acid gel, calcium hydroxylapatite, and black tissue marking dye were topically applied. After treatment, biopsies were collected for histologic evaluation.

RESULTS

Histology revealed that PLLA and black dye were found in greatest abundance, hyaluronic acid was found to a lesser extent, and calcium hydroxylapatite was least found within channels created by fractional CO 2 laser. Microneedling was effective only at delivering black dye, whereas FRMN failed to show significant channel formation or delivery of the studied products.

CONCLUSION

Among the devices and fillers studied, fractional CO 2 laser and PLLA proved to be the most effective combination for laser/device-assisted filler delivery. Neither microneedling nor FRMN was effective as devices to enhance filler delivery.

Melanin-dependent tissue interactions induced by a 755-nm picosecond-domain laser: complementary visualization by optical imaging and histology

Fractional picosecond-domain lasers (PSL) induce optical breakdown, which correlates histologically to vacuolization in the epidermis and dermis. In this ex vivo porcine study, we sought to establish a framework for the investigation of laser-tissue interactions and their dependence on melanin density. Light- (melanin index: 24.5 [0-100]), medium- (58.7), and dark-pigmented (> 98) porcine skin samples were exposed to a 755-nm fractional PSL and examined with dermoscopy, line-field confocal optical coherence tomography (LC-OCT), conventional OCT, and subsequently biopsied for digitally stained ex vivo confocal microscopy (EVCM) and histology, using hematoxylin and eosin (HE) and Warthin-Starry (WS) melanin staining. Dermoscopy showed focal whitening in medium- and dark-pigmented skin. Similarly, LC-OCT and OCT visualized melanin-dependent differences in PSL-induced tissue alterations. Vacuoles were located superficially in the epidermis in dark-pigmented skin but at or below the dermal-epidermal junction in medium-pigmented skin; in light-pigmented skin, no vacuoles were observed. Histology confirmed the presence of vacuoles surrounded by areas void of WS staining and disrupted stratum corneum in darker skin. The combined use of optical imaging for multiplanar visualization and histological techniques for examination of all skin layers may mitigate the effect of common artifacts and attain a nuanced understanding of melanin-dependent laser-tissue interactions.

Effect of Non-Ablative Non-Thermal CO2 Laser on Drug-Resistant Trigeminal Neuralgia: A Pilot Study

Background: Trigeminal neuralgia is one of the most severe pain conditions that humans experience. Drug resistance is a challenging event during treatment that results in using higher doses of drugs or referring for neurosurgical treatment. Laser therapy is also an effective method for pain control. Objective: The aim of this study was to evaluate the effect of non-ablative non-thermal CO₂ laser (NANTCL) on reducing pain in patients with drug-resistant trigeminal neuralgia (DRTN) for the very first time. Materials and methods: Twenty-four patients with DRTN were randomly divided into laser and placebo groups. Patients in the laser group received NANTCL (10,600 nm, 1.1 W, 100 HZ, 20 sec) on trigger points that were covered with lubricant gel 3 days in a week for 2 weeks. The placebo group received sham laser. The patients were requested to grade their pain on a visual analog scale (VAS) immediately, 1 week, 1 month, and 3 months after treatment. Results: In the laser group, the results revealed a significant decrease between the initial pain and the pain in all follow-up sessions. Only in three patients, 3 months after completion of laser therapy, pain returned to the initial level. In the control group, a significant difference was seen only between the pain of baseline and final session of laser irradiation. In laser group, the mean of pain (VAS) was lower than the placebo group in all follow-up sessions; however, it was only significant for 1 week after laser therapy. Conclusions: This study revealed that short-period application of NANTCL is effective for pain relief in patients with DRTN, especially those with extraoral trigger points. Clinical trial registration number: IRCT2013052113406N1.

Laser microporation facilitates topical drug delivery: a comprehensive review about preclinical development and clinical application

INTRODUCTION

Topical drug delivery is highly attractive and yet faces tissue barrier challenges. Different physical and chemical methods have been explored to facilitate topical drug delivery.

AREAS COVERED

Ablative fractional laser (AFL) has been widely explored by the scientific community and dermatologists to facilitate topical drug delivery since its advent less than two decades ago. This review introduces the major efforts in exploration of AFL to facilitate transdermal, transungual, and transocular drug delivery in preclinical and clinical settings.

EXPERT OPINION

Most of the preclinical and clinical studies find AFL to be safe and highly effective to facilitate topical drug delivery with little restriction on physicochemical properties of drugs. Clinical studies support AFL to enhance drug efficacy, shorten treatment time, reduce pain, improve cosmetic outcomes, reduce systemic drug exposure, and improve safety. Considering most of the clinical trials so far involved a small sample size and were in early phase, future trials will benefit from enrolling a large group of patients for thorough evaluation of the safety and efficacy of AFL-assisted topical drug delivery. The manufacturing of small and less costly AFL devices will also facilitate the translation of AFL-assisted topical drug delivery.

Laser-Assisted Drug Delivery: A Systematic Review of Safety and Adverse Events

Laser-assisted drug delivery (LADD) is an increasingly studied and applied methodology for drug delivery. It has been used in a wide variety of clinical applications. Given the relatively low barrier to entry for clinicians as well as ongoing research in this area, the authors aimed to review outcomes relating to safety in laser-assisted drug delivery. A systematic review was conducted, with the databases PubMed, Medline and Embase searched in September 2022. Included articles were those that mentioned laser-assisted drug delivery in human subjects that also reported adverse effects or safety outcomes. There were no language-based exclusions. Conference abstracts and literature reviews were excluded. The results were then tabulated and categorized according to the application of LADD. In total, 501 articles were obtained. Following deduplication, screening, and full text review 70 articles of various study designs were included. Common findings were erythema, oedema, pain, and crusting following LADD. Several notably more severe adverse effects such as generalized urticaria, infection, scarring and dyspigmentation were noted. However, these events were varied depending on the clinical use of LADD. Relevant negatives were also noted whereby no studies reported life-threatening adverse effects. Limitations included limited details regarding the adverse effects within the full texts, lack of follow-up, and risk of bias. In conclusion, there were multiple adverse effects that clinicians should consider prior to carrying out LADD, where treatment goals and patient tolerability should be considered. Further evidence is needed to quantitatively determine these risks.

Efficacy and safety of combined fractional ablative CO2 laser and 5 fluorouracil in the treatment of acral vitiligo: An open, uncontrolled study

BACKGROUND

Acral lesions of vitiligo are most likely recalcitrant to the known lines of treatment. Ablative fractional CO₂ has shown efficacy in treatment of vitiligo in combination with other modalities.

METHODS

Thirty non-segmental vitiligo patients with acral lesion were included in the study. Each patient was subjected to fractional Carbon Dioxide Laser Treatment followed by application of 5 fluorouracil (5FU) cream for five consecutive days. Evaluation was done 3 weeks from the start of treatment and 12 weeks after the last treatment session using VESTA score, evaluation of patients' photos by blinded investigation in addition to patients' satisfaction scores.

RESULTS

Patients showed significant improvement of Vitiligo extent score for a target area (VESTA) score and developed considerable degree of repigmentation as assessed by blinded investigators.

CONCLUSION

The combination of fractional ablative CO₂ and 5FU is an effective and safe procedure for the treatment of acral vitiligo with promising results offering patients a new therapeutic window.

Combination-Based Strategies for the Treatment of Actinic Keratoses with Photodynamic Therapy: An Evidence-Based Review

Photodynamic therapy (PDT) is a highly effective and widely adopted treatment strategy for many skin diseases, particularly for multiple actinic keratoses (AKs). However, PDT is ineffective in some cases, especially if AKs occur in the acral part of the body. Several methods to improve the efficacy of PDT without significantly increasing the risks of side effects have been proposed. In this study, we reviewed the combination-based PDT treatments described in the literature for treating AKs; both post-treatment and pretreatment were considered including topical (i.e., diclofenac, imiquimod, adapalene, 5-fluorouracil, and calcitriol), systemic (i.e., acitretin, methotrexate, and polypodium leucotomos), and mechanical–physical (i.e., radiofrequency, thermomechanical fractional injury, microneedling, microdermabrasion, and laser) treatment strategies. Topical pretreatments with imiquimod, adapalene, 5-fluorouracil, and calcipotriol were more successful than PDT alone in treating AKs, while the effect of diclofenac gel was less clear. Both mechanical laser treatment with CO2 and Er:YAG (Erbium:Yttrium–Aluminum–Garnet) as well as systemic treatment with Polypodium leucotomos were also effective. Different approaches were relatively more effective in particular situations such as in immunosuppressed patients, AKs in the extremities, or thicker AKs. Conclusions: Several studies showed that a combination-based approach enhanced the effectiveness of PDT. However, more studies are needed to further understand the effectiveness of combination therapy in clinical practice and to investigate the role of acitretin, methotrexate, vitamin D, thermomechanical fractional injury, and microdermabrasion in humans.

Evidence-Based Clinical Practice Guidelines for Laser-Assisted Drug Delivery

Importance

Laser-assisted drug delivery (LADD) is used for various medical and cosmetic applications. However, there is insufficient evidence-based guidance to assist clinicians performing LADD.

Objective

To develop recommendations for the safe and effective use of LADD.

Evidence Review

A systematic literature review of Cochrane Central Register of Controlled Trials, Embase, and MEDLINE was conducted in December 2019 to identify publications reporting research on LADD. A multidisciplinary panel was convened to draft recommendations informed by the systematic review; they were refined through 2 rounds of Delphi survey, 2 consensus meetings, and iterative review by all panelists until unanimous consensus was achieved.

Findings

Of the 48 published studies of ablative fractional LADD that met inclusion criteria, 4 were cosmetic studies; 21, oncologic; and 23, medical (not cosmetic/oncologic), and 6 publications of nonablative fractional LADD were included at the request of the expert panel, producing a total of 54 studies. Thirty-four studies (63.0%) were deemed to have low risk of bias, 17 studies (31.5%) had moderate risk, and 3 (5.5%) had serious risk. The key findings that informed the guidelines developed by the expert panel were as follows: LADD is safe in adults and adolescents (≥12 years) with all Fitzpatrick skin types and in patients with immunosuppression; it is an effective treatment for actinic keratosis, cutaneous squamous cell carcinoma in situ, actinic cheilitis, hypertrophic scars, and keloids; it is useful for epidermal and dermal analgesia; drug delivery may be increased through the application of heat, pressure, or occlusion, or by using an aqueous drug solution; laser settings should be selected to ensure that channel diameter is greater than the delivered molecule; antibiotic prophylaxis is not recommended, except with impaired wound healing; antiviral prophylaxis is recommended when treating the face and genitalia; and antifungal prophylaxis is not recommended. The guideline's 15 recommendations address 5 areas of LADD use: (I) indications and contraindications; (II) parameters to report; (III) optimization of drug delivery; (IV) safety considerations; and (V) prophylaxis for bacterial, viral, and fungal infections.

Conclusions and Relevance

This systematic review and Delphi consensus approach culminated in an evidence-based clinical practice guideline for safe and effective use of LADD in a variety of applications. Future research will further improve our understanding of this novel treatment technique.

Fractional CO2 laser versus microneedling as a transepidermal drug delivery system for the treatment of alopecia areata: a clinical dermoscopic evaluation

BACKGROUND AND OBJECTIVES

New treatment modalities are rising for better clinical improvement in alopecia areata. This work aims to evaluate the efficacy of fractional CO2 laser and microneedling as a transepidermal drug delivery in cases with alopecia areata.

METHODS

The study included 30 patients with alopecia areata. All lesions in each patient have received randomly 2 different treatment modalities, fractional CO2 laser or microneedling followed by triamcinolone acetonide (TA) application according to group assignment. Sessions were done every month for a maximum of 6 sessions or complete resolution. Response to treatment was assessed on SALT score and dermoscopic imaging.

RESULTS

Both treatment modalities showed a significant clinical improvement of alopecia areata, with a statistically significant reduction of SALT score for fractional CO2 laser group and microneedling group (p value< 0.001). Moreover, there is a significant difference in the SALT score between both modalities (P=0.013), whereas the reduction of the SALT score was more evident in microneedling group. On comparing the dermoscopy findings in fractional CO2 laser and microneedling treated areas before and after treatment, a significant reduction was found regarding all dermoscopic findings of alopecia areata.

CONCLUSIONS

Fractional CO2 laser and microneedling as a transepidermal drug delivery could be a novel and effective treatment modality in alopecia areata. Dermoscopy is very useful to identify disease activity and early signs of clinical improvement during treatment. This article is protected by copyright. All rights reserved.

Ablative Fractional Laser-assisted Low-irradiance Photodynamic Therapy for Treatment of Actinic Keratoses in Organ Transplant Recipients: A Prospective, Randomized, Intraindividual Controlled Trial

Pain and inferior efficacy are major limiting factors of conventional photodynamic therapy for the field treatment of actinic keratoses in immunosuppressed organ transplant recipients. This prospective randomized controlled study evaluates the efficacy and tolerability of ablative fractional laser system pretreatment combined with low-irradiance photodynamic therapy (18.5 mW/cm2) compared with conventional photodynamic therapy (61.67 mW/cm2) in the treatment of actinic keratoses on the face and scalp in organ transplant recipients, using a red light-emitting diode lamp at a total light dose of 37 J/cm2. Low-irradiance photodynamic therapy combined with Er:YAG pretreatment achieved a significantly superior lesion response rate (mean ± standard deviation 77.3 ± 23.6%) compared with conventional photodynamic therapy (61.8 ± 21.4%; p = 0.025) in intra-individual fields at 3 months without negatively impacting pain (p = 0.777) or cosmetic outcome (p = 0.157).

Micro- and Nano-Based Transdermal Delivery Systems of Photosensitizing Drugs for the Treatment of Cutaneous Malignancies

Photodynamic therapy is one of the more unique cancer treatment options available in today’s arsenal against this devastating disease. It has historically been explored in cutaneous lesions due to the possibility of focal/specific effects and minimization of adverse events. Advances in drug delivery have mostly been based on biomaterials, such as liposomal and hybrid lipoidal vesicles, nanoemulsions, microneedling, and laser-assisted photosensitizer delivery systems. This review summarizes the most promising approaches to enhancing the photosensitizers’ transdermal delivery efficacy for the photodynamic treatment for cutaneous pre-cancerous lesions and skin cancers. Additionally, discussions on strategies and advantages in these approaches, as well as summarized challenges, perspectives, and translational potential for future applications, will be discussed.

A clinical study of carbon dioxide lattice laser-assisted or microneedle-assisted 5-aminolevulinic acid-based photodynamic therapy for the treatment of hypertrophic acne scars

OBJECTIVE

To study the clinical efficacy, recurrence rate and safety of 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) combined with microneedle or CO2 lattice laser (CO2FL), in comparison with intrascar betamethasone injection in the treatment of hypertrophic acne scar.

METHODS

Fifty-two patients with hypertrophic acne scars at the mandibular angle were enrolled and assigned to different therapy groups. Sixteen patients were treated with microneedle-assisted incorporation of ALA. Twenty-eight patients underwent CO2FL-assisted incorporation of ALA. Eight patients received standard therapy with intrascar injection of glucocorticoid. Two dermatologists, blinded to the therapy groups, independently evaluated the scars in all patients using the average value of the Vancouver Scar Scale score, which was treated as an integer variable.

RESULTS

After three rounds of treatment, there was no significant difference in therapeutic effective rate among the microneedle, laser and topical glucocorticoid groups (93.75% vs 100% vs 100%, P = .855). One out of 16 patients (6.25%) in the microneedle group, no patient (0%) in the laser group and two out of eight patients (25%) in the topical glucocorticoid group had recurrence. The laser group showed a higher rate of adverse effects, which were usually mild and reversible, except for pigmentation. Adverse reactions could be completely subsided within 3 weeks.

CONCLUSIONS

Either CO2FL or microneedle combined ALA-PDT for hypertrophic scar, as to topical glucocorticoid therapy, showed equivalent clinical effects but lower recurrence rate within 6 months of follow-up period.

Fractional versus full ablative CO2 laser in recipient site of non-cultured melanocytes and keratinocyte transplantation in treatment of vitiligo

BACKGROUND

Melanocyte-keratinocyte transplant procedure (MKTP) or non-cultured epidermal cell suspension transplantation is a very popular surgical modality for treating stable vitiligo. The recipient-site preparation is one potential determinant in the repigmentation outcomes.

AIM

To assess the efficacy of fractional CO₂ (FCO₂ ) laser in recipient-site preparation before MKTP and comparing it to the frequently used full surface laser ablation.

METHODS

This randomized comparative trial included 19 patients with 40 stable vitiligo lesions. In each patient, the treated sites were randomly categorized into two groups according to the recipient-site ablation (either fractional or full ablative CO₂ laser). Assessment of repigmentation was performed six months after the procedure.

RESULTS

Both modalities achieved successful repigmentation of a median of 80% and 77.5% for fractional and full ablation groups, respectively, with a non-statistically significant difference between them. The median of VASI change percent was -73% and -71% with fractional and full surface ablation, respectively.

CONCLUSIONS

FCO₂ laser ablation is effective for recipient-site preparation before cell suspension transplantation as well as the full ablative CO₂ laser.

Effectiveness and safety of ablative fractional CO2 laser for the treatment of burn scars: A case-control study

BACKGROUND

Burn scars are a major clinical challenge. The aim of this study was to determine the effectiveness and safety of one treatment with the ablative fractional CO2 laser (AFL-CO2) compared to standard burn scar treatment.

METHOD

From December 2014 to October 2018 patients were prospectively recruited and treatment effects analyzed by assessing various outcome parameters from the date of first consultation and after treatment. A case control study was conducted looking at the impact of one AFL-CO2 treatment compared to a cohort subjected to conventional conservative treatment. Adverse effects were noted at follow up.

RESULTS

187 patients were included, with 167 in the AFL-CO2, and 20 in the control cohort. Baseline demographics and scar characteristics showed no significant differences. Ultrasound measured scar thickness as well as the Vancouver Scar Scale (VSS) revealed a significant reduction in the treatment cohort, but no significant improvement in the control group. The POSAS-O was significantly improved in both cohorts. Subjective parameters (POSAS-P, DN4-Pain, and modified D4Pruritus scores) decreased significantly in the AFL-CO2 cohort but remained unchanged in the control group. The BSHS-B quality of life score increased significantly in the AFL-CO2 group, but worsened at the follow up of the untreated patients. Sub-domain analyses found the biggest differences in Affect, Body Image, Heat Sensitivity, Treatment and Work. Complications occurred in 5 patients (2.9%).

CONCLUSIONS

This study demonstrates that AFL-CO2 is an effective and safe treatment modality for burn scars improving thickness, symptoms and quality of life of burn survivors when compared to conventional scar treatment.

Pretreatment with ablative fractional carbon dioxide laser improves treatment efficacy in a synergistic PDT protocol for actinic keratoses on the head

BACKGROUND

A recently proposed synergistic photodynamic therapy protocol (s-PDT) combining advantages of both conventional- and daylight-PDT proved to be an effective and almost painless treatment for patients with actinic keratoses (AKs). This study investigated the safety and efficacy of an additional ablative fractional CO2-laser (AFXL) pretreatment.

METHODS

28 patients with AKs on the head received s-PDT using 5-aminolevulinic acid. AFXL pretreatment was conducted using the following parameters: pulse energy 8 mJ, spot density 50 spots/cm², power 30 W, beam size 4-18 mm. Outcome was assessed by AK area and severity index (AKASI) and lesion count (LC) before and 3 months after treatment. Safety was monitored by blood pressure and pulse measurements. Intensity of pain was determined by use of a visual analog scale (VAS).

RESULTS

Most patients (96.4 %) showed a significant AKASI reduction (P < 0.0001) 3 months after PDT (median AKASI 1.6 [0-2.4]) compared to baseline (5.3 [4-7.75]). Median reduction rate was 75.5 % (61.3 %-100 %). Eleven patients (39.3 %) achieved AKASI 100, three (10.7 %) AKASI 75 and ten (35.7 %) AKASI 50. Blood pressure and pulse did not change significantly throughout treatment. Median VAS for pain during irradiation was 0 (0-0), 0 (0-2) and 0 (0-2) at the beginning, in the meantime and at the end, respectively. Compared to data without AFXL pretreatment, this study showed significantly higher AKASI and LC reduction rates (75.5 % vs. 63.7 % [P = 0.023] and 91.3 % vs. 80.4 % [P = 0.043]).

CONCLUSIONS

S-PDT with AFXL pretreatment represents a safe and almost painless treatment for patients with AKs on the head and improves treatment efficacy.

Fractional CO2 Laser for Transcutaneous Drug Delivery of Onabotulinum Toxin in Palmar Hyperhidrosis

BACKGROUND

Palmar hyperhidrosis is a common disorder of excessive sweating due to over-stimulation of cholinergic receptors on eccrine glands.

OBJECTIVE

To compare the efficacy of laser-assisted drug delivery of onabotulinum toxin A (BoNTA) and intradermal BoNTA injections in the management of palmar hyperhidrosis.

PATIENTS AND METHODS

This intrapatient comparative study was conducted on 30 adult patients with idiopathic palmar hyperhidrosis. The palms of the patients were divided into 2 groups. Group 1 was treated with intradermal injections of 50 units of BoNTA, whereas Group 2 was subjected to laser-assisted transcutaneous BoNTA delivery using fractional CO2 laser at different doses (25, 50, and 75 units). Each treatment modality was evaluated using the iodine starch test, hyperhidrosis disease severity scale, and gravimetric scoring.

RESULTS

Delivery of 75 units of BoNTA to the dermis on the right-sided palms assisted by fractional CO2 laser was clinically equivalent to 50 units of injection on the left side. Pain intensity was significantly higher on the injected side than on the other side.

CONCLUSION

Laser-assisted drug delivery of botulinum toxin can be considered an effective and safe alternative for treatment of palmar hyperhidrosis with minimal side effects and complications.

Combination of Laser Therapy and Photodynamic Therapy with 5-Aminolevulinic Acid Patch for the Treatment of Actinic Cheilitis

Background: Actinic cheilitis (AC) is a premalignant lesion of the lips that can evolve into squamous cell carcinoma. Among nonsurgical treatments, photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA) patch might represent a new noninvasive therapeutic approach for AC. Objective: We sought to investigate the potential role of fractional CO₂ laser pretreatment in boosting ALA penetration and distribution into AC treated with PDT. Methods: We report a case of a woman with AC on the lower lip, treated with ablative fractional CO₂ laser to boost drug delivery of 5-ALA patch before PDT treatment. Reflectance confocal microscopy was performed to assess diagnosis and treatment response. Results: We detected a good clinical and cosmetic outcome after two applications of combined treatment. Erythema, crust, and edema were reported as side effects. Conclusions: This case report shows that ablative fractional CO₂ laser-assisted PDT might be an effective therapeutic alternative for patients with AC who refuse or are contraindicated for surgical procedures.

Comparative Study between Nd-YAG laser, fractional CO2 Laser, and combined Nd-YAG with fractional CO2 Laser in the Management of keloid: clinical and molecular Study

BACKGROUND

Fractional CO2 laser and Nd-YAG laser have been reported to have promising results in the management of keloids. So far, there have been no comparative studies between these laser modalities.

AIMS

The study aimed to compare the efficacy of fractional CO2, Nd-YAG, and a combination of both in the management of keloids.

PATIENTS AND METHODS

Forty-five keloid patients were divided into 3 equal groups: the first received fractional CO2 only, the second received Nd-YAG only, and the third received a combination of both lasers. Each group received its designated treatment every 4 weeks for 4 sessions. The improvement was evaluated by the "Patient and Observer Scar Assessment Scale" (POSAS). Detection of procollagen I mRNA by RT-PCR analysis was done.

RESULTS

The assessment by POSAS showed the most significant clinical improvement in the combination group and a less significant improvement in the fractional CO2 group, while the least improvement was seen in the Nd-YAG group. Molecular assessment via procollagen I yielded matching results.

CONCLUSION

The study showed that the combination of fractional CO2 and Nd-YAG lasers has a synergistic effect being the most effective in the management of keloids, fractional CO2 being more effective than ND-YAG and Nd-YAG being the least effective.

The application of physical pretreatment in photodynamic therapy for skin diseases

Photodynamic therapy (PDT) is widely used in skin diseases; the response rate of PDT treatment varies widely. The limited penetration in the tissue of photosensitizers influenced the penetration depth of PDT, which obviously impacts the therapeutic effect. The studies have improved the efficacy of PDT through various pretreatment applications; especially, the physical pretreatment had achieved significant outcomes. We will review the physical pretreatment to optimize the efficacy of PDT in skin diseases by searching the literature on this topic. The types of physical pretreatment commonly used in the clinical practice are discussed: curettage, superficial shaving, laser, surgical resection, plum-blossom needles, and microneedles. Compared with PDT alone, the physical pretreatment before PDT application was generally improved the efficacy and reduced the recurrence, especially in actinic keratoses (AK), Bowen disease (BD), basal cell carcinoma (BCC), and viral warts. The application of the physical pretreatments before PDT may improve the efficacy of PDT in various skin diseases. However, each kind of physical pretreatment has the benefit and shortcoming, and the applicable situation is different.

Combination of ablative fractional carbon dioxide laser and platelet-rich plasma treatment to improve hypertrophic scars: a retrospective clinical observational study

BACKGROUND

Hypertrophic scars are one of the main complications that affect the quality of life of patients after burns. Many methods have been shown to be effective in the treatment of hypertrophic scars, such as ablative fractional CO₂ laser (AFCL) and platelet-rich plasma (PRP). However, there are few studies on the effect of the combined application of these measures. The purpose of this study was to explore the therapeutic effect of AFCL combined with PRP on hypertrophic burn scars.

METHODS

A retrospective clinical observation study was conducted on 50 patients with hypertrophic burn scars. The AFCL+PRP group included 31 patients who received AFCL combined with PRP treatment; the AFCL group included 19 patients who received AFCL treatment only. The University of North Carolina 4P Scar Scale (UNC4P) and the Vancouver Scar Scale (VSS) scores that were collected before each treatment were used as indicators of the effectiveness of the previous treatment. The scores recorded at the second, fourth and seventh months were analysed.

RESULTS

The demographic data of the 2 groups were not significantly different. Before treatment, there was no difference in the UNC4P and VSS scores between the 2 groups. There was a significant decline in the UNC4P and VSS total scores over 6 months in both groups (p < 0.05) and scores in the 2 groups were comparable after 3 and 6 months (p < 0.05). UNC4P scores in the AFCL+PRP group decreased from a mean of 8.26 to 2.61 (p < 0.05) with a concomitant drop in VSS scores from a mean of 11.74 to 6.06 (p < 0.01). In the AFCL group UNC4P and VSS scores decreased from 7.68 to 4.63 (p < 0.05) and from 10.89 to 8.16 (p < 0.05), respectively. The sub-items of these 2 assessments were analysed and the results suggest that AFCL combined with PRP can comprehensively improve scarring.

CONCLUSIONS

This study shows that PRP is an effective adjunct for AFCL in the treatment of hypertrophic burn scars and that the combination of PRP and AFCL proved to be more useful than AFCL alone. This combination may be a new and effective clinical practice for the treatment of scars. However, larger and higher-level clinical studies are still needed to determine its efficacy and possible mechanisms.

[Photodynamic therapy-trends and new developments]

Photodynamic therapy (PDT) is a licensed and established procedure for the treatment of actinic keratosis, basal cell carcinoma, and Bowen's disease, but there are several new and clinically relevant developments and trends. These concern on the one hand the main components of PDT, which are the photosensitizer and the light source. Furthermore, modifications and therapy combinations have been developed that lead to an improved therapeutic efficacy. An important aspect of field-directed PDT is also skin cancer prevention. Finally, PDT has been used successfully for nonlicensed indications including inflammatory diseases and skin rejuvenation. This article focuses on these new developments and on recent guideline recommendations.

A Comparison of Human and Porcine Skin in Laser-Assisted Drug Delivery of Chemotherapeutics

BACKGROUND AND OBJECTIVES

Porcine skin is a widely used model in diffusion studies, but its usefulness for laser-assisted drug delivery (LADD) has not been evaluated in comparison with human skin. This study compared porcine and human skin in ex vivo LADD diffusion studies.

STUDY DESIGN/MATERIALS AND METHODS

Ex vivo ablative fractional laser (AFL) treatments (5, 20, and 80 mJ/mb) were applied to skin samples from three sources: human, normal pig (Duroc × Landrace × Yorkshire breed), and a hyperkeratotic pig phenotype. Samples were stained using hematoxylin and eosin, photo-documented, and measured digitally. Samples (20 mJ/mb) were exposed to bleomycin or 5-fluorouracil (5-FU) for 19 hours in Franz diffusion cells. Drug uptake was quantified at three skin depths (100, 500, and 1,500 µm) by high-performance liquid chromatography-mass spectrometry. Drug biodistribution and endogenous lipids were visualized by matrix-assisted laser desorption/ionization-mass spectrometry imaging.

RESULTS

Epidermal and dermal thicknesses of human and normal pig skin were similar (76-87 µm and 1,668-1,886 µm, respectively; P = 0.082-0.494). Endogenous lipids were investigated, and 116 compounds were identified. Of these compounds, 100 were found in all three skin types, while six were present exclusively in human skin. Laser channel depths (20 mJ/mb) in human and normal pig skin were similar (1,081 vs. 1,126 µm; P = 0.588). Bleomycin uptake was similar in all skin types at all depths (101.4-175.6 µg/cm³ ; P = 0.132-0.699). 5-FU uptake in human and normal pig skin was similar at 100 and 500 µm (80.5 vs. 140.3 µg/cm³ and 131.2 vs. 208.1 µg/cm³ , respectively; P = 0.065-0.093). At 1500 µm, 5-FU concentrations in the porcine skin types differed from those in human skin (104.7 vs. 196.7-344.8 µg/cm³ ; P = 0.002-0.026). Drug biodistribution was similar among skin types, but differences between bleomycin and 5-FU biodistribution were observed.

CONCLUSIONS

Normal porcine and human skin showed similar morphology, the composition of endogenous lipids, and AFL-assisted cutaneous uptake, and biodistribution of chemotherapeutics. Therefore, normal porcine skin, but not hyperkeratotic pig phenotype skin, is a practical and reliable model for healthy human skin in ex vivo LADD diffusion studies. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Topical Delivery of Nivolumab, a Therapeutic Antibody, by Fractional Laser and Pneumatic Injection

BACKGROUND AND OBJECTIVES

PD-L1 is a tumor ligand that binds to the PD-1 receptor on immune cells, thereby inhibiting the antitumor immune response. The antibody nivolumab is a PD-1 inhibitor, Food and Drug Administration approved for systemic treatment of several aggressive cancer types. Topically applied nivolumab may hold potential as a future strategy to treat keratinocyte cancer, but its molecular properties preclude unassisted topical uptake. The aim of this study was to investigate uptake and biodistribution of topically delivered nivolumab, assisted by two physical enhancement techniques with different delivery kinetics; ablative fractional laser (AFL) and electronically controlled pneumatic injection (EPI).

STUDY DESIGN/MATERIALS AND METHODS

In vitro porcine skin was exposed to CO₂ AFL (20 mJ/mb, 5% density), followed by passive diffusion of nivolumab in a Franz cell (1 mg/ml, 18 hours, n = 6) or treated with EPI (4 bar) for immediate delivery of nivolumab (1 mg/ml, 10 minutes, n = 6). The resulting nivolumab skin concentrations were quantified by enzyme-linked immunosorbent assay (ELISA) at three skin depths (100, 500, and 1500 µm), comparing the uptake from assisted delivery with intact skin. Biodistribution of nivolumab in the skin for all interventions was visualized by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and fluorescence microscopy.

RESULTS

Delivery of nivolumab by AFL-assisted passive diffusion and immediate EPI both resulted in significantly enhanced uptake of nivolumab in all skin depths compared with intact skin (P < 0.05). With AFL, nivolumab concentrations reached 86.3 µg/cm³ (100 µm), 105.8 µg/cm³ (500 µm), and 19.3 µg/cm³ (1500 µm), corresponding to 2-10% of the applied concentration, with the highest deposition in the mid dermis. Immediate EPI delivered 429.4 µg/cm³ (100 µm), 584.9 µg/cm³ (500 µm), and 295.9 µg/cm³ (1500 µm) into the skin, corresponding to 29-58% of the applied nivolumab concentration. From qualitative visualization of the biodistribution, it appeared that nivolumab distributed in a horizontal and continuous homogenous band in the upper and mid dermis through AFL-exposed skin, whereas EPI-delivery showed a deep focal deposition extending into the deep dermis.

CONCLUSIONS

AFL-assisted passive diffusion and immediate EPI-assisted delivery show the potential to deliver therapeutic antibodies locally. Future in vivo and pharmacokinetic studies would reveal the full potential for topical antibody delivery by energy-based devices. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Efficacy and Safety of Laser-Assisted Combination Chemotherapy: An Explorative Imaging-Guided Treatment With 5-Fluorouracil and Cisplatin for Basal Cell Carcinoma

BACKGROUND AND OBJECTIVES

Rising incidences of basal cell carcinoma (BCC) have increased the need for effective topical therapies. By enhancing cutaneous uptake of the chemotherapeutic agents, cisplatin and 5-fluorouracil (5-FU), laser-assisted delivery may provide a new combination treatment for BCC. Accordingly, this study aimed to evaluate tumor response, safety, and drug biodistribution in tumors and blood after topical laser-assisted 5-FU + CIS treatment in BCC patients.

STUDY DESIGN/MATERIALS AND METHODS

This open-label, proof-of-concept trial investigated laser-assisted combination cisplatin + 5-FU treatment in 20 patients with histologically verified, low-risk superficial or nodular BCCs on the face (<20 mm) or trunk/extremities (<50 mm). After tumor demarcation guided by optical coherence tomography (OCT), BCCs were exposed to ablative fractional CO₂ laser followed by 60 minutes topical cisplatin solution and 7-day exposure to 5% 5-FU cream under occlusion. After 30 days, treatment was repeated if any tumor residual was identified. Tumor response at day 30 and month 3 was assessed clinically as well as by OCT, reflectance confocal microscopy, and ultrasound, supplemented by histological verification at 3 months. Local skin reactions (LSRs) and side effects were evaluated on days 1, 3-5, 14, 30, and month 3. Drug detection in tumors and blood was performed in a subset of patients 1- and 24 hours after treatment.

RESULTS

Nineteen patients completed the trial, with 32% (6/19) receiving a single treatment and 68% (13/19) treated twice. At 3 months, clinical clearance was seen in 18/19 patients with a corresponding 94% (17/18) achieving histological clearance. Baseline tumor thickness and subtype did not influence treatment number or clearance rate (P ≥ 0.61). LSRs were well-tolerated and consisted of erythema, edema, and erosion, followed by crusting by day 14. Erythema declined gradually by month 3, with 94% of patients and 79% of physicians rating cosmesis as "good" or "excellent." Scarring or hyperpigmentation was noted in 50% and 56%, respectively, while pain and infection were not observed during the follow-up period. Although chemotherapy uptake was visualized extending to deep skin layers, no systemic exposure to cisplatin or 5-FU was detected in patient blood.

CONCLUSION

Laser-assisted cisplatin + 5-FU shows potential as an effective and tolerable treatment option for low-risk BCC, particularly in instances where self-application is not possible or where in-office, non-surgical therapy is preferred. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Assessment of laser-assisted delivery vs intralesional injection of botulinum toxin A in treatment of hypertrophic scars and keloids

Keloids and hypertrophic scars could impair the psychological, physical, and cosmetic aspects of the patient's quality of life. Unfortunately, there is no curative treatment available till now. This study aimed to evaluate the efficacy and safety of intralesional vs topical botulinum toxin A combined with Fractional CO₂ laser in the treatment of hypertrophic scars and keloids. Twenty patients with Keloids and hypertrophic scars were enrolled in the study. Each scar was divided into two halves, one subjected to intralesional injection of botulinum toxin type A once a month for 4 months and the other was subjected to four sessions of CO₂ laser therapy at 1 month interval followed by topical application of botulinum toxin A. Significant improvement was noted in Vancouver Scar Scale in hypertrophic scars in laser group than intralesional botulinum toxin A. In keloid cases, the improvement was significantly higher with intralesional botulinum toxin A. Clinical improvement showed significant negative correlation with scar duration and size. Botulinum toxin A is a promising treatment for hypertrophic scars and keloids. The use of fractional CO₂ laser as a mode of delivery enhanced the efficacy of botox in hypertrophic scars.

CO2 Fractional Laser Combined with 5-Fluorouracil Ethosomal Gel Treatment of Hypertrophic Scar Macro-, Microscopic, and Molecular Mechanism of Action in a Rabbit Animal Model

The treatment of hypertrophic scar (HS) has thus far been a clinical challenge. We evaluated the therapeutic effect of CO₂ fractional laser combined with 5-fluorouracil ethosomal gel (5-FU EG) in rabbit HS model. HS model was established as standardized scars on the ventral surface of rabbit ears, divided into four groups: control (no intervention), EG treatment, laser treatment, and combined treatment group (laser plus 5-FU EG). Clinical macroscopic and H&E-stained microscopic observations were conducted to assess HS improvement. The mRNA levels of types I and III collagen, transforming growth factor-β1 (TGF-β1), and interleukin-6 (IL-6) were detected by real-time PCR. After 14 days, H&E staining shows that the thickness of HS in treatment groups was significantly lower compared with the control group, and the thickness in laser treatment group and combined treatment group was significantly lower compared with the EG treatment group. The mRNA levels of types I and III collagen, TGF-β1 were significantly low in all treatment groups, whereas IL-6 was highest in the laser treatment group at day 14. The macro- and microscopic effects of the combined and CO₂ fractional laser treatment were better compared with 5-FU EG only. Inhibition of types I and III collagen, TGF-β1 are the possible underlying mechanism of action, whereas the function of IL-6 remains to be further studied. Our study suggests that the effect of combined 5-FU EG and laser, as well as laser-only treatment are superior to 5-FU EG monotreatment. The mechanism of HS improvement is related to reduction of collagen I/III and the inhibition of TGF-β1 expression.

Potentials for implementing pressure-controlled jet injection in management of keloids with intralesional 5FU and corticosteroids

BACKGROUND

Needle-free jet injection implements kinetic energy of liquid jet for transcutaneous delivery of drugs into soft tissues. Combination therapy of intralesional 5-fluorouracil and triamcinolone offers efficacious treatment for keloids with a reduced adverse effect of the drug monotherapy. This study evaluates safety and efficacy of the drug combination administered to keloid scars via intralesional jet injections.

METHODS

A retrospective analysis of the keloid treatments was performed. Efficacy was assessed by reviewing pre- and post-treatment scores of the Vancouver Scar Scale (VSS) and Patient and Observer Scar Assessment Scale (POSAS) and by comparing baseline and photographs taken 3 months after the treatments. Safety and tolerability were collected and analyzed.

RESULTS

Twenty-one subjects (M/F = 11/10) with 39 keloids received the treatments. Treatments were well-tolerated by all patients at mean injection pain of 2.0 ± 1.0 per Numeric Pain Rating Scale (NPRS). Self-resolved lesion ulceration was observed in 4 patients. Post-treatment evaluation demonstrated a 53% decrease in total VSS score (P < 0.05) and in all sub-categories. Mean patient score of POSAS decreased in the color, stiffness, thickness, and irregularity components. Pain and pruritus lessened by 69% and 79% (P < 0.05 in both), respectively, among the patients with complaints prior to the treatment. Independent reviewers reported an average 51%-75% reduction in keloids.

CONCLUSIONS

Improved appearance of keloids and symptomatic relief was achieved by intralesional administration of combined 5-fluorouracil and corticosteroid through the high-pressure jet injections. The synergy between the drug combination and the jet physical impact provided clinical effect.

Laser adjuvant for vaccination

The use of an immunologic adjuvant to augment the immune response is essential for modern vaccines which are relatively ineffective on their own. In the past decade, researchers have been consistently reporting that skin treatment with a physical parameter, namely laser light, augments the immune response to vaccine and functions as an immunologic adjuvant. This "laser adjuvant" has numerous advantages over the conventional chemical or biological agents; it is free from cold chain storage, hypodermic needles, biohazardous sharp waste, irreversible formulation with vaccine antigen, undesirable biodistribution in vital organs, or unknown long-term toxicity. Since vaccine formulations are given to healthy populations, these characteristics render the "laser adjuvant" significant advantages for clinical use and open a new developmental path for a safe and effective vaccine. In addition, laser technology has been used in the clinic for more than three decades and is therefore technically matured and has been proved to be safe. Currently, four classes of laser adjuvant have been reported; ultrashort pulsed, non-pulsed, non-ablative fractional, and ablative fractional lasers. Since each class of the laser adjuvant shows a distinct mechanism of action, a proper choice is necessary to craft an effective vaccine formulation toward a desired clinical benefit for a clinical vaccine to maximize protection. In addition, data also suggest that further improvement in the efficacy is possible when a laser adjuvant is combined with chemical or biological adjuvant(s). To realize these goals, further efforts to uncover the molecular mechanisms of action of the laser adjuvants is warranted. This review provides a summary and comments of the recent updates in the laser adjuvant technology.

Enhanced topical cutaneous delivery of indocyanine green after various pretreatment regimens: comparison of fractional CO2 laser, fractional Er:YAG laser, microneedling, and radiofrequency

Different devices have been used to enhance topical drug delivery. Aim of this study was to compare the efficacy of different skin pretreatment regimens in topical drug delivery. In six ex vivo human abdominal skin samples, test regions were pretreated with fractional CO₂ and Er:YAG laser (both 70 and 300 μm ablation depth, density of 5%), microneedling (500 μm needle length), fractional radiofrequency (ablation depth of ± 80–90 μm), and no pretreatment. The fluorescent agent indocyanine green (ICG) was applied. After 3 h, fluorescence intensity was measured at several depths using fluorescence photography. Significantly higher surface fluorescence intensities were found for pretreatment with fractional Er:YAG and CO₂ laser and for microneedling vs. no pretreatment (p < 0.05), but not for radiofrequency vs. no pretreatment (p = 0.173). Fluorescence intensity was highest for the Er:YAG laser with 300 μm ablation depth (mean 38.89 arbitrary units; AU), followed by microneedling (33.02 AU) and CO₂ laser with 300 μm ablation depth (26.25 AU). Pretreatment with both lasers with 300 μm ablation depth gave higher fluorescence intensity than with 70 μm ablation depth (Er:YAG laser, 21.65; CO₂ laser, 18.50 AU). Mean fluorescence intensity for radiofrequency was 15.27 AU. Results were comparable at 200 and 400 μm depth in the skin. Pretreatment of the skin with fractional CO₂ laser, fractional Er:YAG laser, and microneedling is effective for topical ICG delivery, while fractional radiofrequency is not. Deeper laser ablation results in improved ICG delivery. These findings may be relevant for the delivery of other drugs with comparable molecular properties.

Laser management of hypertrophic burn scars: a comprehensive review

Hypertrophic scars often develop following burn-related injuries. These scars can be cosmetically unappealing, but associated symptoms of pruritus, pain and restricted range of motion can impair a person’s quality of life. Laser and light therapies offer a minimally invasive, low-risk approach to treatment, with a short postoperative recovery period. As laser technology developed, studies have shown decreased scar thickness, neuropathic pain and need for surgical excision, as well as improved scar pigmentation, erythema, pliability, texture, height and pruritus. In this review, we present the evolution of laser therapy for hypertrophic burn scars, how different types of lasers work, indications, perioperative considerations and guidelines for practice management.

Laser facilitates week-long sustained transdermal drug delivery at high doses

Traditional patches are most successful in transdermal delivery of low-dose hydrophobic drugs. Week-long transdermal delivery of high-dose hydrophilic drugs remains a big challenge. This study explored ablative fractional laser (AFL) to assist 3-day to week-long sustained transdermal delivery of powder hydrophilic drugs in murine models. Bulk drug powder was coated into reservoir patches followed by topical application onto AFL-treated skin. Water evaporated from AFL-generated skin microchannels (MCs) gradually dissolve topical drug powder to elicit multi-day sustained drug delivery. Using sulforhodamine b, zidovudine, and bovine serum albumin as model hydrophilic drugs, we found tapped coating could coat 10-20 mg drug per 0.5 cm² reservoir patch to elicit 3-day sustained delivery, while compression coating could coat ~35-70 mg drug per 0.5 cm² reservoir patch to elicit week-long sustained delivery. Besides sustained drug delivery, AFL-assisted powder reservoir patch delivery showed a good safety. AFL-generated skin MCs resealed in 1-2 days and completely recovered in 3 days after the week-long sustained delivery. AFL-assisted powder reservoir patch delivery involves no complex powder formulation and only requires incorporation of highly water-soluble mannitol or a similar excipient to elicit the high-efficient delivery. Enlarging reservoir patch size to 10 cm² can conveniently expand the delivery capacity to gram scale. To our knowledge, this is the first time that high-dose week-long sustained transdermal delivery of hydrophilic drugs was achieved via a simple laser-based powder delivery platform.

Ablative fractional laser-assisted treatments for keratinocyte carcinomas and its precursors-Clinical review and future perspectives

Keratinocyte carcinomas (KC) are the most common malignant human neoplasms. Although surgery and destructive approaches are first-line treatments, topical therapies are commonly used. Due to limited uptake of topical agents across the skin barrier, clearance rates are often sub-optimal. In pre-clinical investigations, ablative fractional laser (AFL)-assisted drug delivery has demonstrated improved uptake of topical drugs commonly used to treat KC. In 22 clinical trials, the effect of AFL-assisted treatments has been investigated for actinic keratosis (AK; n = 14), Bowen's disease (BD; n = 5), squamous cell carcinoma (n = 1), and basal cell carcinoma (n = 7). The most substantial evidence currently exists for AFL-assisted photodynamic therapy for the treatment of AK and BD. AFL improved 12-months follow-up clearance rates of photodynamic therapy from 45.0-51.0% to 78.5-84.8% for AK and from 50.0-55.3% to 87.0-87.5% for BD. AFL-assisted pharmacological therapy is a promising tool for optimizing topical treatments of KC and its precursor lesions. Future developments include AFL-assisted immune activation, changing drug administration route of systemic therapies, and utilizing drug chemo-combinations.

Fundamentals of fractional laser-assisted drug delivery: An in-depth guide to experimental methodology and data interpretation

In the decade since their advent, ablative fractional lasers have emerged as powerful tools to enhance drug delivery to and through the skin. Effective and highly customizable, laser-assisted drug delivery (LADD) has led to improved therapeutic outcomes for several medical indications. However, for LADD to reach maturity as a standard treatment technique, a greater appreciation of its underlying science is needed. This work aims to provide an in-depth guide to the technology's fundamental principles, experimental methodology and unique aspects of LADD data interpretation. We show that drug's physicochemical properties including solubility, molecular weight and tissue binding behavior, are crucial determinants of how laser channel morphology influences topical delivery. Furthermore, we identify strengths and limitations of experimental models and drug detection techniques, interrogating the usefulness of in vitro data in predicting LADD in vivo. By compiling insights from over 75 studies, we ultimately devise an approach for intelligent application of LADD, supporting its implementation in the clinical setting.

Split-Sided Chest Study of Skin Rejuvenation Comparing Low-Energy, 1,927-nm Thulium Fractional Laser Treatment Prior to Photodynamic Therapy Versus Photodynamic Therapy Alone

Background and Objectives

Treatment of photoaging and intrinsic aging of the chest, with the associated concerns of skin roughness, uneven pigmentation, laxity, atrophy, and telangiectasias, can be problematic because of the potential for worsened esthetic outcomes with existing treatments. This study assessed the efficacy and safety of using nonablative fractional laser therapy (FLT) pretreatment with photodynamic therapy (PDT) versus PDT alone for chest rejuvenation.

Study Design/Materials and Methods

In a randomized, evaluator‐blinded, split‐sided study, adult female patients with photodamage to the chest received three treatment courses over an 8‐week period with follow‐up visits at Weeks 12 and 20. FLT was applied to one side of the chest, randomly assigned at baseline, followed by aminolevulinic acid‐based PDT, delivered using a thermal, short incubation, broad area technique, to both sides of the chest. In‐person and photographic assessments were conducted using five‐point scales to evaluate outcomes including rhytides, pigmentation, skin texture, and telangiectasias.

Results

Eleven adults completed the study, of whom 11 had improved scores for rhytides and 10 had improved scores for skin texture at Week 20. There was no significant difference in any efficacy outcome between FLT and PDT and standard PDT alone. The severity of adverse events was rated significantly greater with the combined FLT–PDT treatment vs PDT alone.

Conclusions

Significant improvements were observed vs baseline for both sides of the chest treated with FLT–PDT or standard PDT following three treatment sessions. No significant difference in efficacy was observed between treatment approaches, although adverse events were more severe on the FLT‐pretreated side. This study was not registered as it qualified as a nonsignificant risk study. Lasers Surg. Med. © 2019 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

Effect of fractional ablative carbon dioxide laser with lidocaine spray on skin flap survival in rats

Background

Lidocaine spray is a local anesthetic that improves random-pattern skin flap survival. The fractional ablative carbon dioxide laser (FxCL) produces vertical microchannels that delivers topically applied drugs to the skin. In this study, we hypothesized that FxCL therapy would enhance the lidocaine effect to improve random-pattern skin flap survival in rats.

Methods

McFarlane random-pattern skin flaps were elevated in 48 rats, which were divided into four groups according to treatment: FxCL+lidocaine, FxCL, lidocaine, and nontreatment (control). On postoperative day 7, necrotic flap areas, the number of capillary vessels, and neutrophil count were evaluated. Anti-rat vascular endothelial growth factor (VEGF) and CD31 antibody activity were also evaluated by immunohistochemical staining.

Results

Flap survival rate was 53.41%± 5.43%, 58.16%± 4.80%, 57.08%± 5.91%, and 69.08%±3.20% in the control, lidocaine, FxCL, and FxCL+lidocaine groups, respectively. Mean neutrophil count in the intermediate zone excluding the necrotic tissue was 41.70± 8.40, 35.43± 6.41, 37.23±7.15, and 27.20± 4.24 cells/field in the control, lidocaine, FxCL, and FxCL+lidocaine groups, respectively. Anti-rat VEGF and CD31 antibody activity were the highest in the FxCL+lidocaine group.

Conclusion

FxCL with lidocaine had a positive effect on random-pattern skin flap survival in rats. Thus, FxCL with lidocaine spray should be considered as a new treatment option to improve flap viability.