Photodynamic Therapy In Dermatology Research Articles

Antibacterial nanophotosensitizers in photodynamic therapy: An update.

Bacterial infections constitute a major challenge of clinical medicine, particularly in specialties such as dermatology and dental medicine. Antiseptics and antibiotics are the main adjunctive therapies to anti-infective procedures in these specialties. However, antibacterial photodynamic therapy (PDT) has been introduced as a novel and promising alternative to conventional antibacterial approaches. PDT relies on the formation of reactive oxygen species (ROS) by a photosensitizer (PS) after activation by a specific light source. Nanotechnology was later introduced to enhance the antibacterial efficacy of PS during PDT. In this review, we describe the different nanoparticles (NPs) used in PDT and their properties. Recent in vivo data of NPs in antibacterial PDT in dermatology and dental medicine and their safety concerns are also reviewed.

Photodynamic therapy in dermatology: Beyond current indications.

Photodynamic therapy (PDT) has long been used in dermatology as a therapeutic strategy for several malignant and premalignant conditions. Currently, it is approved in Europe for the treatment of actinic keratosis, squamous cell carcinoma in situ, and some forms of basal cell carcinoma, with favorable clearance rates associated with satisfying aesthetic results. Nonetheless, in the past few years, PDT has also demonstrated efficacy in many other conditions, including inflammatory and infectious dermatoses. These results, probably explained by its immunomodulatory, anti-inflammatory, and bactericidal effects, may lead to an expansion of PDT indications in the upcoming years. In this article, conditions where PDT may be useful are reviewed, thus highlighting the potential of this therapeutic modality for the dermatologist.

Hexyl aminolevulinate, 5-aminolevulinic acid nanoemulsion and methyl aminolevulinate in photodynamic therapy of non-aggressive basal cell carcinomas: A non-sponsored, randomized, prospective and double-blinded trial.

In the photodynamic therapy (PDT) of non-aggressive basal cell carcinomas (BCCs), 5-aminolevulinic acid nanoemulsion (BF-200ALA) has shown non-inferior efficacy when compared with methyl aminolevulinate (MAL), a widely used photosensitizer. Hexyl aminolevulinate (HAL) is an interesting alternative photosensitizer. To our knowledge, this is the first study using HAL-PDT in the treatment of BCCs. To compare the histological clearance, tolerability (pain and post-treatment reaction) and cosmetic outcome of MAL, BF-200 ALA and low-concentration HAL in the PDT of non-aggressive BCCs. Ninety-eight histologically verified non-aggressive BCCs met the inclusion criteria, and 54 patients with 95 lesions completed the study. The lesions were randomized to receive LED-PDT in two repeated treatments with MAL, BF-200 ALA or HAL. Efficacy was assessed both clinically and confirmed histologically at three months by blinded observers. Furthermore, cosmetic outcome, pain, post-treatment reactions fluorescence and photobleaching were evaluated. According to intention-to-treat analyses, the histologically confirmed lesion clearance was 93.8% (95% confidence interval [CI] = 79.9-98.3) for MAL, 90.9% (95% CI=76.4-96.9) for BF-200 ALA and 87.9% (95% CI=72.7-95.2) for HAL, with no differences between the arms (P=0.84). There were no differences between the arms as regards pain, post-treatment reactions or cosmetic outcome. Photodynamic therapy with low-concentration HAL and BF-200 ALA has a similar efficacy, tolerability and cosmetic outcome compared to MAL. HAL is an interesting new option in dermatological PDT, since good efficacy is achieved with a low concentration.

Light emitting fabrics for photodynamic therapy: Technology, experimental and clinical applications

AbstractA homogeneous and reproducible fluence rate delivery during clinical photodynamic therapy (PDT) plays a determinant role in preventing under‐ or overtreatment. The development of a flexible light source able to generate uniform light on all its surface would considerably improve the homogeneity of light delivery. The integration of plastic optical fibers into textile structures offers an interesting alternative. This article aims to describe briefly the technology used to develop light emitting fabrics (LEF) and their use in vitro (CELL‐LEF), in vivo (VIVO‐LEF) for experimental evaluation of PDT. Finally, the use of LEF for clinical applications is given by three examples. For in vitro applications, the CELL‐LEF device allows the illumination of several 96‐well cell culture plates. For the VIVO‐LEF, the system developed for PDT can treat three mice simultaneously with a homogeneous and high irradiance The medical LEF systems developed for PDT in dermatology for the treatment of actinic keratosis demonstrate their superiority thanks to a uniform light distribution due the flexibility of LEF. Interestingly, the technology used for manufacturing LEF is very well known by the textile industry, leading to very competitive production costs. The fact that optical fibers can transmit light from 400 to 1200 nm allows the connection of LEF to different laser sources covering the light spectrum of all photosensitizers used for medical applications. New developments should allow to use the LEF inside cavities such as the pleural or the peritoneal cavities.

European Dermatology Forum guidelines on topical photodynamic therapy 2019 Part 2: emerging indications - field cancerization, photorejuvenation and inflammatory/infective dermatoses.

In addition to approved indications in non-melanoma skin cancer in immunocompetent patients, topical photodynamic therapy (PDT) has also been studied for its place in the treatment of, as well as its potential to prevent, superficial skin cancers in immune-suppressed patients, although sustained clearance rates are lower than for immune-competent individuals. PDT using a nanoemulsion of ALA in a daylight or conventional PDT protocol has been approved for use in field cancerization, although evidence of the potential of the treatment to prevent new SCC remained limited. High-quality evidence supports a strong recommendation for the use of topical PDT in photorejuvenation as well as for acne, refractory warts, cutaneous leishmaniasis and in onychomycosis, although these indications currently lack approvals for use and protocols remain to be optimized, with more comparative evidence with established therapies required to establish its place in practice. Adverse events across all indications for PDT can be minimized through the use of modified and low-irradiance regimens, with a low risk of contact allergy to photosensitizer prodrugs, and no other significant documented longer-term risks with no current evidence of cumulative toxicity or photocarcinogenic risk. The literature on the pharmacoeconomics for using PDT is also reviewed, although accurate comparisons are difficult to establish in different healthcare settings, comparing hospital/office-based therapies of PDT and surgery with topical ointments, requiring inclusion of number of visits, real-world efficacy as well as considering the value to be placed on cosmetic outcome and patient preference. This guideline, published over two parts, considers all current approved and emerging indications for the use of topical photodynamic therapy in Dermatology prepared by the PDT subgroup of the European Dermatology Forum guidelines committee. It presents consensual expert recommendations reflecting current published evidence.

European Dermatology Forum guidelines on topical photodynamic therapy 2019 Part 1: treatment delivery and established indications - actinic keratoses, Bowen's disease and basal cell carcinomas.

Topical photodynamic therapy (PDT) is a widely approved therapy for actinic keratoses, Bowen's disease (squamous cell carcinoma insitu), superficial and certain thin basal cell carcinomas. Recurrence rates when standard treatment protocols are used are typically equivalent to existing therapies, although inferior to surgery for nodular basal cell carcinoma. PDT can be used both as lesional and field therapies and has the potential to delay/reduce the development of new lesions. A protocol using daylight to treat actinic keratoses is widely practised, with conventional PDT using a red light after typically a 3-h period of occlusion employed for other superficial skin cancer indications as well as for actinic keratoses when daylight therapy is not feasible. PDT is a well-tolerated therapy although discomfort associated with conventional protocol may require pain-reduction measures. PDT using daylight is associated with no or minimal pain and preferred by patient. There is an emerging literature on enhancing conventional PDT protocols or combined PDT with another treatment to increase response rates. This guideline, published over two parts, considers all current approved and emerging indications for the use of topical PDT in dermatology, prepared by the PDT subgroup of the European Dermatology Forum guidelines committee. It presents consensual expert recommendations reflecting current published evidence.

Regression Analysis of Protoporphyrin IX Measurements Obtained During Dermatological Photodynamic Therapy.

Photodynamic therapy (PDT) is a light activated drug therapy that can be used to treat a number of dermatological cancers and precancers. Improvement of efficacy is required to widen its application. Clinical protoporphyrin IX (PpIX) fluorescence data were obtained using a pre-validated, non-invasive imaging system during routine methyl aminolevulinate (MAL)-PDT treatment of 172 patients with licensed dermatological indications (37.2% actinic keratosis, 27.3% superficial basal cell carcinoma and 35.5% Bowen’s disease). Linear and logistic regressions were employed to model any relationships between variables that may have affected PpIX accumulation and/or PpIX photobleaching during irradiation and thus clinical outcome at three months. Patient age was found to be associated with lower PpIX accumulation/photobleaching, however only a reduction in PpIX photobleaching appeared to consistently adversely affect treatment efficacy. Clinical clearance was reduced in lesions located on the limbs, hands and feet with lower PpIX accumulation and subsequent photobleaching adversely affecting the outcome achieved. If air cooling pain relief was employed during light irradiation, PpIX photobleaching was lower and this resulted in an approximate three-fold reduction in the likelihood of achieving clinical clearance. PpIX photobleaching during the first treatment was concluded to be an excellent predictor of clinical outcome across all lesion types.

An experimental investigation of a novel iron chelating protoporphyrin IX prodrug for the enhancement of photodynamic therapy.

ObjectivesNon‐melanoma skin cancers are the most frequently occurring type of cancer worldwide. They can be effectively treated using topical dermatological photodynamic therapy (PDT) employing protoporphyrin IX (PpIX) as the active photosensitising agent as long as the disease remains superficial. Novel iron chelating agents are being investigated to enhance the effectiveness and extend the applications of this treatment modality, as limiting free iron increases the accumulation of PpIX available for light activation and thus cell kill.MethodsHuman lung fibroblasts (MRC‐5) and epithelial squamous carcinoma (A431) cells were treated with PpIX precursors (aminolaevulinic acid [ALA] or methyl‐aminolevulinate [MAL]) with or without the separate hydroxypyridinone iron chelating agent (CP94) or alternatively, the new combined iron chelator and PpIX producing agent, AP2‐18. PpIX fluorescence was monitored hourly for 6 hours prior to irradiation. PDT effectiveness was then assessed the following day using the lactate dehydrogenase and neutral red assays.ResultsGenerally, iron chelation achieved via CP94 or AP2‐18 administration significantly increased PpIX fluorescence. ALA was more effective as a PpIX‐prodrug than MAL in A431 cells, corresponding with the lower PpIX accumulation observed with the latter congener in this cell type. Addition of either iron chelating agent consistently increased PpIX accumulation but did not always convey an extra beneficial effect on PpIX‐PDT cell kill when using the already highly effective higher dose of ALA. However, these adjuvants were highly beneficial in the skin cancer cells when compared with MAL administration alone. AP2‐18 was also at least as effective as CP94 + ALA/MAL co‐administration throughout and significantly better than CP94 supplementation at increasing PpIX fluorescence in MRC5 cells as well as at lower doses where PpIX accumulation was observed to be more limited.ConclusionsPpIX fluorescence levels, as well as PDT cell kill effects on irradiation can be significantly increased by pyridinone iron chelation, either via the addition of CP94 to the administration of a PpIX precursor or alternatively via the newly synthesized combined PpIX prodrug and siderophore, AP2‐18. The effect of the latter compound appears to be at least equivalent to, if not better than, the separate administration of its constituent parts, particularly when employing MAL to destroy skin cancer cells. AP2‐18 therefore warrants further detailed analysis, as it may have the potential to improve dermatological PDT outcomes in applications currently requiring enhancement. Lasers Surg. Med. 50:552–565, 2018. © 2018 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

Gain with no pain? Pain management in dermatological photodynamic therapy

Pain during photodynamic therapy (PDT) is the main limiting adverse effect in its use in dermatology. Given its multifactorial nature, we reviewed both intrinsic and extrinsic factors that are involved in PDT pain. We propose a threshold theory for pain experience in PDT: it correlates positively with fluence rate and dose below a certain threshold (rate of ~60 mW cm-2 , dose of ~50J cm-2 ); when the threshold is surpassed, pain intensity saturates. Additionally, we carefully compared recent updates on pain management strategies and we suggest that cold-air analgesia and low-irradiance light sources (such as variable pulsed light and daylight PDT) represent the current best analgesic options. Finally, we discuss the possible mechanisms of pain experience during PDT. Reactive oxygen species, transient receptor potential channels and inflammatory responses are key mediators in pain. Further investigation into these pathways should help with the development of more effective analgesic strategies. Taking these points together, for pain management in PDT, an individualized plan of analgesia is possible.

Developing a dermatological photodiagnosis system by optical image analyses and in vivo study

Dermatological photodynamic therapy (DPDT) involves using systematic photosensitizers in combination with light irradiation treatment to eliminate cancer cells. Therefore, a noninvasive fluorescence photodiagnosis system is critical in DPDT for diagnosing target tissues and demarcating the margin of normal tissues. This study proposes a 375-nm ring LED light module in fluorescence imaging for DPDT applications. Image reproducibility (I.R.) and image interference (I.I.) analysis were performed. The results showed that the I.R. value of this fluorescence diagnostic system was higher than 99.0%, and the I.I. from external light sources was lower than 3.0%. In addition, the result of an in vivo study showed that the Chlorin e6 red fluorescence and the scope of distribution of B16-F10 melanoma cells in a mouse ear’s vein could be measured clearly using our device; however, the comparison studio with 395-nm LED lights could not focus or capture the red fluorescence effectively.

Epidermal penetration and protoporphyrin IX formation of two different 5-aminolevulinic acid formulations in ex vivo human skin

BackgroundPhotosensitizer formation and epidermal penetration depth represent basic predictors of drug efficacy in dermatological Photodynamic Therapy (PDT). Different drug formulations and application standards are used to perform PDT in clinical practice. MethodsThus, we developed a human ex vivo model suitable to explore drug permeation in human skin and compared in 10 patients the penetration of nanoemulsion formulation (BF-200 ALA) with that of a 20% ALA cream formulation frequently used in clinical practice. Protoporphyrin IX (PpIX) formation was assessed according to different durations of incubation with both preparations. ResultsBF-200 ALA led to more intense PpIX fluorescence than the 20% ALA cream formulation as assessed by fluorescence microscopy: after 12h of incubation, total measured fluorescence was at 101,995 fluorescence units with BF-200 ALA and 40,960 fluorescence units with 20% ALA cream, respectively. This could be reproduced using quantitative fluorimetric measurements in tissue lysates. After the clinically relevant incubation time of 3h the PpIX concentration induced by BF-200 ALA was more than three-fold higher than that induced by the 20% ALA formulation (7.1±5.5 and 1.9±1.8nmol/l, p<0.05, Mann–Whitney U-test) and four-fold higher after 12h (30.0±4.6 and 6.7±2.0nmol/l, p<0.01, Mann–Whitney U-test). ConclusionsIn spite of the 50% lower ALA content BF-200 ALA triggers significantly higher PpIX concentrations than the 20% ALA formulation, indicating that clinical efficacy with BF-200 ALA may be higher. Moreover, the ex vivo eyelid skin model may represent a useful tool to investigate drug permeation in human skin.

Topical PDT in the Treatment of Benign Skin Diseases: Principles and New Applications.

Photodynamic therapy (PDT) uses a photosensitizer, light energy, and molecular oxygen to cause cell damage. Cells exposed to the photosensitizer are susceptible to destruction upon light absorption because excitation of the photosensitizing agents leads to the production of reactive oxygen species and, subsequently, direct cytotoxicity. Using the intrinsic cellular heme biosynthetic pathway, topical PDT selectively targets abnormal cells, while preserving normal surrounding tissues. This selective cytotoxic effect is the basis for the use of PDT in antitumor treatment. Clinically, PDT is a widely used therapeutic regimen for oncologic skin conditions such as actinic keratosis, squamous cell carcinoma in situ, and basal cell carcinoma. PDT has been shown, under certain circumstances, to stimulate the immune system and produce antibacterial, and/or regenerative effects while protecting cell viability. Thus, it may be useful for treating benign skin conditions. An increasing number of studies support the idea that PDT may be effective for treating acne vulgaris and several other inflammatory/infective skin diseases, including psoriasis, rosacea, viral warts, and aging-related changes. This review provides an overview of the clinical investigations of PDT and discusses each of the essential aspects of the sequence: its mechanism of action, common photosensitizers, light sources, and clinical applications in dermatology. Of the numerous clinical trials of PDT in dermatology, this review focuses on those studies that have reported remarkable therapeutic benefits following topical PDT for benign skin conditions such as acne vulgaris, viral warts, and photorejuvenation without causing severe side effects.

European Dermatology Forum Guidelines on topical photodynamic therapy.

Topical photodynamic therapy (PDT) is a widely approved therapy for actinic keratoses, squamous cell carcinoma in-situ, superficial and certain thin basal cell carcinomas. Recurrence rates are typically equivalent to existing therapies, although inferior to surgery for nodular basal cell carcinoma. PDT can be used both as a lesional or as a field therapy and has the potential to delay/reduce the development of new lesions. PDT has also been studied for its place in the treatment of, as well as its potential to prevent, superficial skin cancers in immune-suppressed patients, although sustained clearance rates are lower than for immunocompetent individuals. Many additional indications have been evaluated, including photo-rejuvenation and inflammatory and infective dermatoses. This S2 guideline considers all current and emerging indications for the use of topical photodynamic therapy in Dermatology, prepared by the PDT subgroup of the European Dermatology Forum guidelines committee. It presents consensual expert recommendations reflecting current published evidence. An unabridged version of this guideline is available online at: http://www.euroderm.org/edf/index.php/edf-guidelines.

Current Evidence and Applications of Photodynamic Therapy in Dermatology

Jaclyn S. Effron, CNP Apex Dermatology and Skin Surgery Center Cleveland, Ohio Objectives 1. To demonstrate the mechanism of action of photodynamic therapy in the treatment of various skin conditions. 2. To explain the applications of photodynamic therapy in dermatology for the treatment of actinic keratosis and non-melanoma skin cancers. 3. To examine the the state of current evidence for PDT in the management of inflammatory skin conditions, such as acne and rosacea, as well as the potential therapeutic benefits of PDT for antiaging/photorejuvenation.

Current Evidence and Applications of Photodynamic Therapy in Dermatology

Journal of the Dermatology Nurses’ Association: May/June 2015 - Volume 7 - Issue 3 - p 152-153 doi: 10.1097/JDN.0000000000000135

La PDT antimicrobienne en dermatologie. Partie II : les infections virales et parasitaires ; les perspectives

La PDT antimicrobienne en dermatologie. Partie II : les infections virales et parasitaires ; les perspectives

La photothérapie dynamique antimicrobienne en dermatologie. Partie I : les infections bactériennes et fongiques

La photothérapie dynamique antimicrobienne en dermatologie. Partie I : les infections bactériennes et fongiques

Practical approach to the use of daylight photodynamic therapy with topical methyl aminolevulinate for actinic keratosis: a European consensus.

Daylight-mediated photodynamic therapy has been shown to be an effective therapy for actinic keratoses (AKs) and a simple and tolerable treatment procedure in three randomized Scandinavian studies and two recent Phase III randomized controlled studies in Australia and Europe. To establish consensus recommendations for the use of daylight photodynamic therapy (DL-PDT) using topical methyl aminolaevulinate (MAL) in European patients with AKs. The DL-PDT consensus recommendations were developed on behalf of the European Society for Photodynamic Therapy in Dermatology and comprised of 10 dermatologists from different European countries with experience in how to treat AK patients with PDT. Consensus was developed based on literature review and experience of the experts in the treatment of AK using DL-PDT. The recommendations arising from this panel of experts provide general guidance on the use of DL-PDT as a dermatological procedure with specific guidance regarding patient selection, therapeutic indications, when to treat, pre-treatment skin preparation, MAL application and daylight exposure for patients with AK in different countries of Europe. This consensus recommendation provides a framework for physicians to perform DL-PDT with MAL cream while ensuring efficiency and safety in the treatment of patients with AK in different European countries.

Current evidence and applications of photodynamic therapy in dermatology.

In photodynamic therapy (PDT) a photosensitizer – a molecule that is activated by light – is administered and exposed to a light source. This leads both to destruction of cells targeted by the particular type of photosensitizer, and immunomodulation. Given the ease with which photosensitizers and light can be delivered to the skin, it should come as no surprise that PDT is an increasingly utilized therapeutic in dermatology. PDT is used commonly to treat precancerous cells, sun-damaged skin, and acne. It has reportedly also been used to treat other conditions including inflammatory disorders and cutaneous infections. This review discusses the principles behind how PDT is used in dermatology, as well as evidence for current applications of PDT.

Challenging Approach with Nanoformulation and Photodynamic Therapy in Dermatology

Background:Photodynamic therapy (PDT) and holds substantial promise in improving outcomes of patients with a form of cutaneous conditions and dermatological conditions such as keratosis and basal cell carcinoma, etc. Use of 5-aminolevulinic acid (ALA) was sanctioned as secure and effective for use as a treatment. Methods:In our work, we used Photodynamic therapy in patients with selected skin cancerization, and evaluated the fluorescence from photo sensitizer to constitute the field cancerization, which helps in analyzing the efficacy of the technique. Results:From our study, it is clear that use of ALA with PDT against different skin cancerization has significant effects. However, the effect of efficacy varied according to the type of carcinoma. In our study, we observed that nano- ALA with PDT targeted about 70-80% more skin lesion and the mean reduction area of skin cancerization was about 10% greater with nano-ALA and PDT. Conclusion:Our findings suggest use of ALA-PDT as a simple, cost effective, and novel method that can be used for various skin cancerization treatments.