Tolerability and comparative effectiveness of TNF-, IL-17-, and IL-23(p19) inhibitors in psoriatic arthritis: A target trial emulation study.

OBJECTIVES: To compare tolerability and effectiveness of two different classes of biological Disease-Modifying Anti-Rheumatic Drugs (bDMARDs; interleukin (IL)-17- and IL-23(p19) inhibitors) relative to tumour necrosis factor inhibitors (TNFi) regarding the drug survival rates and treatment outcomes in patients with psoriatic arthritis (PsA). METHODS: We emulated a target trial on comparative effectiveness using observational data from a prospective cohort study based on the Parker Institute's PsA cohort - the PIPA cohort. All patients underwent interview and clinical examination programme at baseline and at follow-up visits at four and twelve months. The primary endpoint, drug survival, was assessed up to 12 months from baseline. We estimated hazard ratios from proportional hazards model and used propensity score adjustment in an attempt to deconfound and emulate a random treatment assignment. RESULTS: We included a total of 109 patients in the intention-to-monitor population at baseline initiating either TNFi (75 patients), IL17i (26 patients), or IL23(19)i (8 patients). Hazard ratios in the propensity adjusted model comparing IL-17i and IL-23(p19)i to TNFi were 1.36 (95% CI 0.59-3.14) and 0.56 (95% CI 0.10-3.24), respectively. TNFi and IL-17i had comparable effects regarding response rates and changes in clinical outcomes after 12 months, whereas IL-23(p19)i tended to perform better overall. CONCLUSION: No decisive differences between drugs were observed at group level regarding drug survival and clinical outcomes after 12 months. TNFi, IL-17i, and IL-23(p19)i may all be considered equally effective in the treatment of patients with PsA, advocating for investigating more in personalised treatment strategies.

Confocal microscopy and optical coherence tomography of inflammatory skin diseases in hairs and pilosebaceous units: A systematic review.

Common skin disorders such as acne vulgaris, rosacea and folliculitis are bothersome prevalent inflammatory diseases of hair follicles that can easily be investigated bedside using optical coherence tomography (OCT) and reflectance confocal microscopy (RCM) with micrometre resolution, opening a novel era for high-resolution hair follicle diagnostics and quantitative treatment evaluation. EMBASE, PubMed and Web of Science were searched until 5 January 2023 to identify all studies imaging hair follicle characteristics by RCM and OCT for diagnosis and monitoring of treatment in hair follicle-based skin disorders. This study followed PRISMA guidelines. After inclusion of articles, methodological quality was assessed using the QUADAS-2 critical appraisal checklist. Thirty-nine in vivo studies (33 RCM and 12 OCT studies) were included. The studies focused on acne vulgaris, rosacea, alopecia areata, hidradenitis suppurativa, folliculitis, folliculitis decalvans, lichen planopilaris, discoid lupus erythemasus, frontal fibrosing alopecia and keratosis pilaris. Inter- and perifollicular morphology including number of demodex mites, hyperkeratinization, inflammation and vascular morphology could be assessed by RCM and OCT in all included skin disorders. Methodological study quality was low, and interstudy outcome variability was high. Quality assessment showed high or unclear risk of bias in 36 studies. Both RCM and OCT visualize quantitative features as size, shape, content and abnormalities of hair follicles, and have potential to support clinical diagnosis and evaluate treatment effects. However, larger studies with better methodological quality are needed to implement RCM and OCT directly into clinical practice.

Detection of cutaneous malignant melanoma by tape stripping of pigmented skin lesions - A systematic review.

BACKGROUND: Cutaneous malignant melanoma (MM) is potentially aggressive, and numerous clinically suspicious pigmented skin lesions are excised, causing unnecessary mutilation for patients at high healthcare costs, but without histopathological evidence of MM. The high number of excisions may be lowered by using more accurate diagnostics. Tape stripping (TS) of clinically suspicious lesions is a non-invasive diagnostic test of MM that can potentially lower the number needed to biopsy/excise. MATERIALS AND METHODS: The aim is to determine the diagnostic accuracy of TS in detecting MM in clinically suspicious pigmented skin lesions. This systematic review following PRISMA guidelines searched PubMed, Web of Science, and Embase (September 2022) using melanoma combined with tape stripping, adhesive patch(es), pigmented lesion assay, or epidermal genetic information retrieval. RESULTS: Ten studies were included. Sensitivity ranged from 68.8% (95% confidence interval [CI] 51.5, 82.1) to 100% (95% CI 91.0, 100). Specificity ranged from 69.1% (95% CI 63.8, 74.0) to 100% (95% CI 78.5, 100). A pooled analysis of five studies testing the RNA markers LINC00518 and PRAME found a sensitivity of 86.9% (95% CI 81.7, 90.8) and a specificity of 82.4% (95% CI 80.8, 83.9). CONCLUSION: Overall quality of studies was low, and the reliability of sensitivity and specificity is questionable. However, TS may supplement well-established diagnostic methods as pooled analysis of five studies indicates a moderate sensitivity. Future studies are needed to obtain more reliable data as independent studies with no conflict of interest.

Assessing Light and Energy-Based Therapy by Optical Coherence Tomography and Reflectance Confocal Microscopy: A Randomized Trial of Photoaged Skin.

BACKGROUND AND OBJECTIVES: Image-guided quantitative and semi-quantitative assessment of skin can potentially evaluate treatment efficacy. Optical coherence tomography (OCT) and reflectance confocal microscopy (RCM) are ideal for this purpose. This study assessed clinically relevant statistical changes in RCM and OCT features in photoaged skin after light and energy-based therapy. METHODS: Novel statistical analyses were performed using OCT and RCM data collected during a previously published trial: a 12-week study of female décolleté skin randomized to four areas treated with thulium laser (L), photodynamic therapy (PDT), combined L-PDT, and control. Eight semi-quantitative RCM scores of photodamage and OCT measurements of skin roughness, blood flow, and epidermal thickness (ET) were evaluated and compared to dermoscopy and clinical skin scores. In statistical analysis, estimated treatment difference (ETD) was calculated. RESULTS: Twelve women with moderate to severe photodamage were included. RCM and OCT data demonstrated a trend towards rejuvenation of epidermis with increased ET, changes in skin surface, and improved honeycomb pattern in RCM. In angiographic OCT, non-significant changes towards more regular capillary meshes were shown, which matched a decline in appearance of gross telangiectasias in dermoscopy. Improved skin tone after laser and L-PDT was identified in RCM, showing less edged papillae in 36% and 45%, and lentigo number declined in 55% of patients after treatments in dermoscopy. Based on clinical scores, L-PDT provided the greatest clinical improvement, which corresponded to superior ETD outcomes in ET and edged papillae shown in OCT and RCM, respectively. CONCLUSION: Objective OCT and RCM assessment of skin rejuvenation was demonstrated in this study. Importantly, image-based improvements corresponded to favorable clinical skin scores and fewer photoaging characteristics in dermoscopy. Importantly, most changes did not reach statistical significance, prompting further studies and emphasizing the modest value of non-randomized, non-blinded anti-aging trials.

Differentiation Between Benign and Malignant Pigmented Skin Tumours Using Bedside Diagnostic Imaging Technologies: A Pilot Study.

Rapid diagnosis of suspicious pigmented skin lesions is imperative; however, current bedside skin imaging technologies are either limited in penetration depth or resolution. Combining imaging methods is therefore highly relevant for skin cancer diagnostics. This pilot study evaluated the ability of optical coherence tomography, reflectance confocal microscopy, photo-acoustic imaging and high-frequency ultrasound to differentiate malignant from benign pigmented skin lesions. A total of 41 pigmented skin tumours were scanned prior to excision. Morphological features and blood vessel characteristics were analysed with reflectance confocal microscopy, optical coherence tomography, high-frequency ultrasound and photoacoustic imaging images, and the diagnostic accuracy was assessed. Three novel photoacoustic imaging features, 7 reflectance confocal microscopy features, and 2 optical coherence tomography features were detected that had a high correlation with malignancy; diagnostic accuracy > 71%. No significant features were found in high-frequency ultrasound. In conclusion, optical coherence tomography, reflectance confocal microscopy and photoacoustic imaging in combination enable image-guided bedside evaluation of suspicious pigmented skin tumours. Combining these advanced techniques may enable more efficient diagnosis of skin cancer.

Skin tags imaged by reflectance confocal microscopy, optical coherence tomography and multispectral optoacoustic tomography at the bedside.

BACKGROUND: Skin tags are common and mostly benign, but occasionally contain skin cancers. This study analysed skin tags by combining three advanced optical imaging technologies: reflectance confocal microscopy (RCM), optical coherence tomography (OCT) and multispectral optoacoustic imaging (MSOT) supplemented by dermoscopy MATERIALS AND METHODS: A prospective clinical study recruiting patients with skin tags from a university hospital clinic over a 2-week period. OCT, RCM and MSOT imaging were performed prior to excisional biopsies. Image features such as pigmentation, cell types and skin architecture, angiographic information demonstrating vascular pattern were captured, analysed, and compared to melanin and haemoglobin content in MSOT as well as histopathology. RESULTS: Six patients with dermal naevi (2); compound naevi (3); neurofibroma (1) were included. All skin tags except the neurofibroma were pigmented (5/6), with sparse (5/6) and dense (4/6) hyperreflective nests and band-like collagen in dermis in 6/6 lesions on RCM. Dermoscopy showed dots (5/6) and coiled vessels (5/6). Linear vertical vessels were present in all OCT images. MSOT images consisted of a compact shell-like superficial melanin area, same shape and size as the skin tag, dermal vessels were visible in 4/5 naevi, HbO2 signal clearly demarcated blood vessels located below the melanin signal. CONCLUSION: OCT showed linear vessels in all lesions. Pigmentation was identified by RCM as benign nests of melanocytes. MSOT supplemented with spatial distribution of melanin and HbO2 that indicated all skin tags were benign with no infiltration of vessels inside the melanin signal. Each advanced method proved indispensable for fast diagnosis. Larger studies are warranted for validation.

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.

The ß3-integrin endothelial adhesome regulates microtubule-dependent cell migration.

Integrin ß3 is seen as a key anti-angiogenic target for cancer treatment due to its expression on neovasculature, but the role it plays in the process is complex; whether it is pro- or anti-angiogenic depends on the context in which it is expressed. To understand precisely ß3's role in regulating integrin adhesion complexes in endothelial cells, we characterised, by mass spectrometry, the ß3-dependent adhesome. We show that depletion of ß3-integrin in this cell type leads to changes in microtubule behaviour that control cell migration. ß3-integrin regulates microtubule stability in endothelial cells through Rcc2/Anxa2-driven control of active Rac1 localisation. Our findings reveal that angiogenic processes, both in vitro and in vivo, are more sensitive to microtubule targeting agents when ß3-integrin levels are reduced.

In Vivo Reflectance Confocal Microscopy of Gold Microparticles Deposited in the Skin. A Case Report on Cutaneous Chrysiasis.

Cutaneous chrysiasis is gold deposition in the dermis, described after parenteral administration of gold salts or after topical exposure to gold-containing materials. Gold microparticles (GMPs) have versatile therapeutic effects and are increasingly used in medicine. This case report describes the development of a blue-gray macule following the facial application of GMPs and laser treatment of acne vulgaris. Dermoscopy showed a nonspecific homogenous blue-gray pattern, gradually fading over an 8-month-period. Reflectance confocal microscopy (RCM) detected hyperreflective, subcellular particles in the papillary dermis, localized around hair follicles, eccrine glands, and inside macrophages. Histopathological evaluation, darkfield illumination with hyperspectral imaging, and neutron activation analysis confirmed the presence of GMPs in the dermis. RCM allowed non-invasive fast visualization of aggregates of hyperreflective particles in the dermis and can potentially be used for monitoring localized cutaneous chrysiasis and other metal deposition conditions over time. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

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.

Association of metabolites reflecting type III and VI collagen formation with modified Rodnan skin score in systemic sclerosis - a cross-sectional study.

Objective: The objective was to investigate blood-based biomarkers of type I (PRO-C1), III (PRO-C3) and VI (PRO-C6) collagen formation in systemic sclerosis (SSc) patients and examine their correlation to modified Rodnan skin score (mRSS). Methods: Limited (lSSc, n = 76) and diffuse SSc (dSSc, n = 41) fulfilling the ACR/EULAR 1980 and 2013 classification criteria for SSc and asymptomatic controls (n = 9) were included. PRO-C1, PRO-C3 and PRO-C6 were measured in serum. Results: LSSc compared to dSSc were significantly older, had longer disease duration and lower mRSS. PRO-C3 was higher in early dSSc compared to early lSSc (mean [95 percentile], 27.4 [13.1-39.1] ng/mL vs 14.9 [8.2-28.8] ng/mL, p = 0.006). PRO-C6 levels were higher in early dSSc compared to early lSSc and late dSSc (early dSSc: 28.2 [10.4-92.3] ng/ml vs early lSSc: 11.0 [6.9-28.5] ng/ml; p = 0.006 and late dSSc: 12.6 [6.5-25.3] ng/mL, p = 0.04). No difference was observed with PRO-C1. PRO-C3 and PRO-C6 were moderately correlated with mRSS with R-partials of 0.36 (p < 0.001) and 0.29 (p = 0.002), respectively Conclusion: Measures of type III and VI collagen formation are potential objective biomarkers of fibrosis in systemic sclerosis. These biomarkers could be useful in monitoring the disease and efficacy of treatment.

Transfollicular delivery of gold microparticles in healthy skin and acne vulgaris, assessed by in vivo reflectance confocal microscopy and optical coherence tomography.

INTRODUCTION: Topical application of gold microparticles (GMPs) for selective photothermolysis is a recently FDA-cleared therapy for acne vulgaris. Current evidence indicates the potential of optical imaging to non-invasively visualize GMPs and describe photothermal tissue effects. OBJECTIVES: To qualitatively and quantitatively describe GMP delivery in vivo and visualize laser-mediated thermal effects of GMPs in facial skin of acne patients and healthy participants, using reflectance confocal microscopy (RCM) and optical coherence tomography (OCT). METHODS: Patients with facial acne (n = 14), and healthy participants (n = 7) were included. RCM and OCT images were acquired at baseline, after GMP application, and after diode laser exposure. All images were evaluated qualitatively and quantitatively with regards to GMP delivery in skin layers and morphological thermal effects. Lastly, skin biopsies were obtained to compare RCM and OCT findings to histology. RESULTS: GMPs were delivered equally in healthy participants and acne patients, and in lesional and non-lesional acne skin. In RCM images, GMPs appeared as hyperreflective aggregates inside hair follicles and eccrine ducts, corresponding to natural skin openings (NSOs). The fraction of NSOs with hyperreflective content increased significantly after GMP application compared to baseline (50-75% increase, P = 8.88 × 10-16 ). Similarly, in OCT images, GMPs appeared as hyperreflective columns inside hair follicles and were not detected in surrounding skin. GMPs reached a maximum depth of 920 µm (median 300 µm). After laser exposure, RCM and histology revealed selective perifollicular tissue changes around NSOs. CONCLUSION: Optical imaging visualizes GMP delivery and thermal tissue response following laser exposure and enables bedside monitoring of transfollicular microparticle delivery. Lasers Surg. Med. 51:430-438, 2019. © 2019 Wiley Periodicals, Inc.

Acne vulgaris severity graded by in vivo reflectance confocal microscopy and optical coherence tomography.

INTRODUCTION: Acne is an inflammatory disease of the pilosebaceous unit, which can be investigated in vivo using reflectance confocal microscopy (RCM) and optical coherence tomography (OCT). OBJECTIVES: By means of RCM and OCT to identify morphological characteristics of acne that may be associated with clinical acne severity. METHODS: Patients with mild to moderate facial acne (n = 14, Investigators Global Assessment scale, IGA 1-3), and healthy participants (n = 7, IGA 0) were included in this explorative study. A total of 108 RCM image blocks and 54 OCT scans (each RCM and OCT image measuring 6 × 6 mm) were captured from lesional-, perilesional, and lesion-free skin areas. Acne lesions, infundibular regions of follicles and inflammation degree were compared in acne patients and healthy participants. RESULTS: Combined use of RCM and OCT demonstrated infundibular morphology, acne lesions, and blood flow. RCM images of perilesional- and lesion-free skin in acne patients revealed follicle infundibula with hyperkeratinized borders and abundant keratin plugs, contrasting skin of healthy participants. Higher acne severity related to increased number of follicles with hyperkeratotic borders (P = 0.04) and keratin plugs (P = 0.006), increased infundibulum diameter (P < 0.001), increased density of inflammatory cells (P < 0.001), and blood flow (P = 0.03). Acne lesion morphology was not associated with acne severity. CONCLUSION: Combined use of RCM and OCT elucidated distinctive follicle infundibulum characteristics and inflammation degree that were associated with acne severity. Future trials may apply imaging techniques to support clinical acne grading, and monitor treatment efficacy. Lasers Surg. Med. 51:104-113, 2019. © 2018 Wiley Periodicals, Inc.

Noninvasive measurement of reepithelialization and microvascularity of suction-blister wounds with benchmarking to histology.

We explored use of the suction-blister wound model in the assessment of not only epidermal regeneration but also pain, the microvascular response and bacteriology. The effects of topical zinc sulfate were studied to articulate the methodologies in this double-blind trial. One epidermal suction blister (10 mm) was induced on each buttock in 30 healthy volunteers (15 females:15 males) and deroofed on day 0. The wounds were randomized to daily treatment with 1.4% zinc sulfate shower gel (n = 20), placebo (n = 20) or control (n = 20). Digital photography coupled with planimetry, transepidermal water loss (TEWL) measurement and optical coherence tomography (OCT) was benchmarked to the gold standard of histology of 60 full-thickness wound biopsies on day 4. Pain increased after application of the shower gels. Microvessel density, determined from OCT images, increased from day 0 to day 2 in the three groups but increased more with the placebo than with the zinc shower gel (p = 0.003) or the control treatment (p = 0.002) and correlated (rS = 0.313, p = 0.015) with the inflammatory response on day 4, as determined by histology. Coagulase-negative staphylococci were more common in wounds compared with skin (p = 0.002) and was reduced (p = 0.030) with zinc sulfate treatment. Planimetric analysis of digital wound images was not biased (p = 0.234) compared with histology, and TEWL measurements showed no correlation (rS = 0.052, p = 0.691) with epithelialization. Neoepidermal formation, determined by histology, did not differ (p = 0.290) among the groups. Zinc sulfate reduced (p = 0.031) the release of lactate dehydrogenase from cultured gel-treated keratinocytes isolated from the blister roofs. Therefore, combination of the standardized suction-blister wound model with noninvasive planimetry and OCT is a useful tool for assessing wound therapies. Zinc sulfate transiently dampened inflammation and reduced bacterial growth.

Fractional laser-assisted drug uptake: Impact of time-related topical application to achieve enhanced delivery.

BACKGROUND AND OBJECTIVE: Ablative fractional laser (AFXL) is acknowledged to increase uptake of topically applied agents in skin. AFXL channels gradually close over time, which may impair this capability. The time frame for applying a drug after AFXL exposure remains to be established. The aim of this study, was to investigate the importance of time-related topical application after AFXL exposure and to relate resultant uptake in skin with AFXL channel morphology and skin integrity. STUDY DESIGN/MATERIALS AND METHODS: Buttock skin of healthy volunteers (n = 11) was exposed to 10,600 nm fractional CO2 laser using 5% density, 120 µm beam diameter, 15 mJ pulse energy. Sodium fluorescein (NaF) a small, hydrophilic molecule (370 MW, log P = -1.52) was applied under standardized conditions at specific time points after laser exposure (0, 2, 5, 10, 30, 60, 90 minute, 6, 24, and 48 hours). Fluorescence photography collected fluorescence images up to 180 minute after NaF application. Optical coherence tomography (OCT) assessed AFXL channel dimensions and transepidermal water loss (TEWL) estimated loss of skin integrity. RESULTS: Fluorescence intensities (FI) were significantly elevated when NaF was applied up to 6 hours after laser exposure compared to non-laser-processed skin (median FI 1947 arbitrary units [interquartile range 1,246-3,560] versus 1,004 [350-1,538], P < 0.02). The highest FI occurred when NaF was applied within 30 minute after laser exposure and similar FI were reached for applications at 0, 2, 5, 10, and 30 minute after AFXL exposure (0 minute: 3,866 [3,526-4,575], 30 minute: 3,775 AU [3,070-4,484], P > 0.1). NaF application later than 30 minute after AFXL exposure resulted in gradually decreasing FI, becoming similar to intact skin when applied at 24-48 hours after AFXL exposure (P > 0.2). OCT images demonstrated that AFXL channels closed over time (100% [100-100%] open up to 30 minute, 75% [4-86%] at 6 hours and 3% [0-15%] at 24-48 hours after AFXL exposure). TEWL measurements proved loss of skin integrity up to 6 hours after AFXL exposure, while integrity was similar in laser-exposed and non-laser-exposed skin at 24-48 hours. CONCLUSIONS: The time frame to maintain enhanced drug delivery sustained for several hours after AFXL exposure, corresponding to channel morphology and loss of skin integrity. Lasers Surg. Med. 49:348-354, 2017. © 2016 Wiley Periodicals, Inc.

Vehicle type affects filling of fractional laser-ablated channels imaged by optical coherence tomography.

Ablative fractional laser (AFXL) is an emerging method that enhances topical drug delivery. Penetrating the skin in microscopic, vertical channels, termed microscopic treatment zones (MTZs), the fractional technique circumvents the skin barrier and allows increased uptake of topically applied drugs. This study aims to elucidate the impact of vehicle type on the filling of MTZs from application of liquid, gel, and cream vehicles. Ex vivo pig skin was exposed to 10,600 nm fractional CO2 laser at 5% density, 120 µm beam diameter, and fluences of 40 and 80 mJ/microbeam (mJ/mb). Six repetitions were performed for each of six interventions (2 fluences and 3 vehicle types, n = 36). MTZ dimensions and filling by vehicle type were evaluated by optical coherence tomography, using blue tissue dye as a contrast-enhancing agent. Outcome measure was degree of MTZ filling assessed as percentages of empty, partially filled, and completely filled MTZs (108-127 MTZs/intervention analyzed) and evaluated statistically using Kruskal-Wallis and Dunn's tests. MTZs reached mid-dermal levels of 225 µm (40 mJ/mb) and 375 µm (80 mJ/mb) penetration depths (p < 0.0001). Filling of MTZs depended on type of applied vehicle. At 80 mJ/mb, liquid (67% completely filled, p < 0.01) and gel (60%, p < 0.05) formulations filled MTZs significantly better than cream formulation (31%). At 40 mJ/mb, liquid and gel formulations filled 90% (p < 0.05) and 77% (p > 0.05) of MTZs completely versus 55% for cream formulation. Thus, filling was overall greater for more superficial MTZs. In conclusion, vehicle type affects filling of MTZs, which may be of importance for AFXL-assisted drug delivery.