Laser-induced thermal coagulation enhances skin uptake of topically applied compounds.

BACKGROUND: Ablative fractional laser (AFL) generates microchannels in skin surrounded by a zone of thermally altered tissue, termed the coagulation zone (CZ). The thickness of CZ varies according to applied wavelength and laser settings. It is well-known that AFL channels facilitate uptake of topically applied compounds, but the importance of CZ is unknown. METHODS: Franz Cells were used to investigate skin uptake and permeation of fluorescent labeled polyethylene glycols (PEGs) with mean molecular weights (MW) of 350, 1,000, and 5,000 Da. Microchannels with CZ thicknesses ranging from 0 to 80 µm were generated from micro-needles (0 µm, CZ-0), and AFL (10,600 nm) applied to -80°C deep frozen skin (20 µm, CZ-20) and skin equilibrated to room temperature (80 µm, CZ-80). Channels penetrated into similar mid-dermal skin depths of 600-700 µm, and number of channels per skin area was similar. At 4 hours incubation, skin uptake of PEGs into CZ and dermis was evaluated by fluorescence microscopy at specific skin depths of 150, 400, and 1,000 µm and the transcutaneous permeation was quantified by fluorescence of receptor fluids. RESULTS: Overall, the highest uptake of PEGs was reached through microchannels surrounded by CZ compared to channels with no CZ (CZ-20 and CZ-80>CZ-0).The thickness of CZ affected PEG distribution in skin. A thin CZ-20 favored significantly higher mean fluorescence intensities inside CZ areas compared to CZ-80 (PEG 350, 1,000, and 5,000; P < 0.001). In dermis, the uptake through CZ-20 channels was significantly higher than through CZ-80 and CZ-0 at all skin depths (PEG 350, 1,000 and 5,000, 150-1,000 µm; P < 0.001). Correspondingly, transcutaneous permeation of PEG 350 was highest in CZ-20 compared to CZ-80 and CZ-0 samples (P < 0.001). Permeation of larger molecules (PEG 1,000 and PEG 5,000) was generally low. CONCLUSION: Uptake of topical compounds is higher through microchannels surrounded by a CZ than without a CZ. Moreover, CZ thickness influences PEG distribution, with highest PEG uptake achieved from microchannels surrounded by a thin CZ. Lasers Surg. Med. 49:582-591, 2017. © 2017 Wiley Periodicals, Inc.

Ablative fractional laser enhances MAL-induced PpIX accumulation: Impact of laser channel density, incubation time and drug concentration.

BACKGROUND AND OBJECTIVES: Pretreatment of skin with ablative fractional laser enhances accumulation of topical provided photosensitizer, but essential information is lacking on the interaction between laser channel densities and pharmacokinetics. Hence our objectives were to investigate how protoporphyrin accumulation was affected by laser densities, incubation time and drug concentration. METHODS: We conducted the study on the back of healthy male volunteers (n=11). Test areas were pretreated with 2940nm ablative fractional Er:YAG laser, 11.2mJ per laser channel using densities of 1, 2, 5, 10 and 15% (AFL 1-15%). Control areas received pretreatment with curettage or no pretreatment. Methyl aminolevulinate (MAL) was applied under occlusion in concentrations of 0, 80 and 160mg/g. MAL-induced protoporphyrin fluorescence was quantified with a handheld photometer after 0, 30, 60, 120 and 180min incubation. The individual fluorescence intensity reached from the highest density (15%) and longest MAL 160mg/g incubation time (180min) was selected as reference (100%) for other interventional measurements. RESULTS: A low laser density of 1% markedly enhanced fluorescence intensities from 34% to 75% (no pretreatment vs. AFL 1%, MAL 160mg/g, 180min; p<0.001). Furthermore, fluorescence intensities increased substantially by enhancing densities up to 5% (p≤0.0195). Accumulation of protoporphyrins was accelerated by laser exposure. Thus, laser exposure of 5% density and a median incubation time of 80min MAL (range 46-133min) induced fluorescence levels similar to curettage and 180min incubation. Furthermore, MAL 80 and 160mg/g induced similar fluorescence intensities in skin exposed to laser densities of 1, 2 and 5% (p>0.0537, 30-180min). CONCLUSION: MAL-induced protoporphyrin accumulation is augmented by enhancing AFL densities up to 5%. Further, this model indicates that incubation time as well as drug concentration of MAL may be reduced with laser pretreatment.

Adjuvant eflornithine to maintain IPL-induced hair reduction in women with facial hirsutism: a randomized controlled trial.

BACKGROUND: Photoepilation is the treatment of choice for hair removal in patients with hirsutism, but it remains a challenge to prevent regrowth of hairs. OBJECTIVES: The objective of this study was to investigate whether topical eflornithine maintains hair reduction in hirsute patients after cessation of intense pulsed light (IPL) therapy. METHODS: A randomized, split-face, single-blinded controlled trial on topical eflornithine vs. no eflornithine treatment (control) after 5-6 IPL-treatments in 22 women with facial hirsutism. Application of eflornithine was initiated after the final IPL-treatment (baseline) and applied twice daily for 6 months to half of the face. Patients were assessed at baseline and 1, 3 and 6 months after the final IPL-treatment. The primary endpoint was difference in facial hair counts between eflornithine vs. no treatment. Secondary endpoints were patient-evaluated efficacy, patient satisfaction and safety. RESULTS: A total of 18 patients completed the study protocol. At 1 month after final IPL-treatment, eflornithine reduced hair regrowth by 14% (P = 0.007, n = 20 patients), at 3 months by 9% (P = 0.107, n = 19) and at 6 months by 17% (P = 0.048, n = 18) compared to no treatment. Patient-evaluated efficacy supported blinded hair counts and patients were satisfied with eflornithine treatment throughout the study (median VAS 5-6). Eflornithine was generally well tolerated, but blinded evaluation demonstrated deterioration of acne in two patients at final assessment. CONCLUSION: Topical eflornithine provides a self-administered treatment with a potential to maintain IPL-induced hair reduction in hirsute patients.

Ablative fractional laser alters biodistribution of ingenol mebutate in the skin.

Topically applied ingenol mebutate (IngMeb) is approved for field-treatment of actinic keratosis and is currently being investigated for treatment of non-melanoma skin cancer (NMSC). Ablative fractional lasers (AFXLs) generate microscopic ablation zones (MAZs) in the skin, which may help induce a deep penetration needed for effective treatment of NMSC. Using Franz diffusion cells, uptake and bio-distribution were investigated over 21 h in intact (n = 9) and AFXL-exposed porcine skin (n = 58). A 2940-nm fractional Er:YAG laser generated intraepidermal (11.2 mJ/MAZ; 66 µm deep, 177 µm wide) and intradermal (128 mJ/MAZ; 570 µm deep, 262 wide) MAZ's with 16, 97, and 195 MAZs/cm(2). Surface ablation densities corresponded to 0.5, 2.5, and 5 % for intraepidermal MAZs, and corresponded to 1, 5, and 10.5 % for intradermal MAZs. Liquid-chromatography-mass-spectrometry quantified deposition of IngMeb in stratum corneum, epidermis, dermis, and receiver chamber. In intact skin, IngMeb readily penetrated to the epidermal layer (1,314 ng, 41 % of the applied IngMeb), while dermal deposition was limited (508 ng, 16 %). In AFXL-exposed skin, a profound dermal deposition of IngMeb was achieved, while less accumulated in SC and epidermis. Uptake depended entirely on laser density; increasing coverage from 0 % to 0.5 %, 1 %, 2.5 %, 5 %, and 10.5 % enhanced dermal uptake 1.6-, 2.1-, 3.1-, 3.4-, and 3.9-fold, respectively (p < 0.0001). Channel depth did not influence drug uptake; at 5 % density, dermal deposition with intraepidermal and intradermal MAZs was analogous (1801 vs. 1744; p = 0.447). In conclusion, IngMeb readily distributes to superficial layers of intact skin, whereas dermal uptake is limited. Independent of channel depth, AFXL enhances dermal drug deposition, providing for customized topical delivery and potential use of IngMeb for treatment of NMSC.

Fractional laser-mediated photodynamic therapy of high-risk basal cell carcinomas--a randomized clinical trial.

BACKGROUND: Photodynamic therapy (PDT) is approved for selected nodular basal cell carcinomas (nBCC) but efficacy is reduced for large and thick tumours. Ablative fractional lasers (AFXL) facilitate uptake of methyl aminolaevulinate (MAL) and may thus improve PDT outcome. OBJECTIVES: To evaluate efficacy and safety of AFXL-mediated PDT (AFXL-PDT) compared with conventional PDT of high-risk nBCC. METHODS: Patients with histologically verified facial nBCC (n = 32) defined as high-risk tumours were included; diameter > 15 mm, tumours located in high-risk zones, or on severely sun-damaged skin. Tumours were debulked and patients randomized to either AFXL-PDT (n = 16) or PDT (n = 16). Fractional CO2 laser treatment was applied at 5% density and 1000 µm (80 mJ) ablation depth. MAL was applied under occlusion for 3 h and illuminated with a 633-nm light-emitting diode source, 37 J cm(-2) . Clinical assessments were performed at 3, 6, 9 and 12 months and biopsies were taken at 12 months. RESULTS: Clinical cure rates at 3 months were 100% (16 of 16 AFXL-PDT) and 88% (14 of 16 PDT, P = 0·484). Recurrences tended to occur later and in lower numbers after AFXL-PDT at 6, 9 and 12 months (6%, 19%, 19%) than PDT (25%, 38%, 44%) (P = 0·114). Histology at 12 months documented equal tumour clearance after AFXL-PDT (63%, 10 of 16) and PDT (56%, 9 of 16). Cosmetic outcomes were highly satisfactory after both treatments (P > 0·090). CONCLUSIONS: Long-term efficacy was similar after PDT and AFXL-PDT with a trend for a favourable short-term cure rate after AFXL-PDT. AFXL-PDT needs further refinement for nBCC and at present is not recommended over PDT.

Intensified photodynamic therapy of actinic keratoses with fractional CO2 laser: a randomized clinical trial.

BACKGROUND: Photodynamic therapy (PDT) with methyl aminolaevulinate (MAL) is effective for thin actinic keratoses (AKs) in field-cancerized skin. Ablative fractional laser resurfacing (AFXL) creates vertical channels that facilitate MAL uptake and may improve PDT efficacy. OBJECTIVES: To evaluate efficacy and safety of AFXL-assisted PDT (AFXL-PDT) compared with conventional PDT in field-directed treatment of AK. METHODS: Fifteen patients with a total of 212 AKs (severity grade I-III) in field-cancerized skin of the face and scalp were randomized to one treatment with PDT and one treatment with AFXL-PDT in two symmetrical areas. Following curettage of both treatment areas, AFXL was applied to one area using 10 mJ per pulse, 0·12 mm spot, 5% density, single pulse (UltraPulse(®), DeepFx handpiece; Lumenis Inc., Santa Clara, CA, U.S.A.). MAL cream was then applied under occlusion for 3 h and illuminated with red light-emitting diode light at 37 J cm(-2). Fluorescence photography quantified protoporphyrin IX (PpIX) before and after illumination. RESULTS: At 3-month follow-up, AFXL-PDT was significantly more effective than PDT for all AK grades. Complete lesion response of grade II-III AK was 88% after AFXL-PDT compared with 59% after PDT (P = 0·02). In grade I AK, 100% of lesions cleared after AFXL-PDT compared with 80% after PDT (P = 0·04). AFXL-PDT-treated skin responded with significantly fewer new AK lesions (AFXL-PDT n = 3, PDT n = 11; P = 0·04) and more improved photoageing (moderate vs. minor improvement, P = 0·007) than PDT-treated skin. Pain scores during illumination (6·5 vs. 5·4; P = 0·02), erythema and crusting were more intense, and long-term pigmentary changes more frequent from AFXL-PDT than PDT (P = not significant). PpIX fluorescence was higher in AFXL-pretreated skin [7528 vs. 12,816 arbitrary units (AU); P = 0·003] and photobleached to equal intensities after illumination (AFXL-PDT 595 AU, PDT 454 AU; P = 0·59). CONCLUSIONS: AFXL-PDT is more effective than conventional PDT for treatment of AK in field-cancerized skin.

Hair removal in hirsute women with normal testosterone levels: a randomized controlled trial of long-pulsed diode laser vs. intense pulsed light.

BACKGROUND: Hirsutism is a common disorder in women of reproductive age, and androgen disturbances may aggravate the condition. Limited evidence exists regarding efficacy of hair removal in this specific population and no data are available for patients with verified normal testosterone levels. OBJECTIVES: To compare efficacy and safety of intense pulsed light (IPL) vs. long-pulsed diode laser (LPDL) in a well-defined group of hirsute women with normal testosterone levels. METHODS: Thirty-one hirsute women received six allocated split-face treatments with IPL (525-1200 nm; Palomar Starlux IPL system) and LPDL (810 nm; Asclepion MeDioStar XT diode laser). Testosterone levels were measured three times during the study period. Patients with intrinsically normal or medically normalized testosterone levels throughout the study were included in efficacy assessments (n = 23). Endpoints were reduction in hair counts assessed by blinded photoevaluations at baseline and 1, 3 and 6 months after final treatment, patient-evaluated reduction in hairiness, patient satisfaction, treatment-related pain and adverse effects. RESULTS: IPL and LPDL reduced hair counts significantly, with median reductions from baseline of 77%, 53% and 40% for IPL and 68%, 60% and 34% for LDPL at 1, 3 and 6 months, respectively. At 6 months follow-up, there was no significant difference between treatments in terms of hair reduction (P = 0·427), patient assessment of hairiness (P = 0·250) and patient satisfaction (P = 0·125). Pain scores were consistently higher for IPL [median 6, interquartile range (IQR) 4-7] than LPDL (median 3, IQR 2-5) (P < 0·001). CONCLUSION: Hirsute women with normal or medically normalized testosterone levels responded equally well to IPL and LPDL treatments of facial hairiness, but the efficacy declined over 6 months.