Photodynamic therapy with 5-aminolaevulinic acid or placebo for recalcitrant foot and hand warts: randomised double-blind trial

A novel H‑tert immortalized human sebaceous gland cell line (XL-i-20) for the investigation of photodynamic therapy

BACKGROUND

Acne vulgaris is a species-specific human disease. To date, there has been no established human sebocyte cell line of Asian origin. Our previous study has demonstrated the efficacy of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) in the treatment of acne vulgaris, primarily attributed to its cytotoxic properties; however, its regulatory mechanism remains largely unknown.

OBJECTIVES

To establish an immortalized human sebocyte cell line derived from Chinese population and investigate the underlying mechanism of ALA-PDT.

METHODS

Human primary sebocytes were transfected with the human tert gene (h‑tert). The biological characteristics, including cell proliferation, cell markers, and sebum secretion function, were compared between primary sebocytes and the immortalized sebocytes (XL-i-20). Stimulations such as ALA-PDT, were applied respectively to both primary sebocytes and XL-i-20 cells to assess changes in their cellular functions. The transcriptome differences between primary sebocytes and XL-i-20 sebocytes were investigated using RNA-seq analysis. The XL-i-20 cell line was used to establish a sebaceous gland (SG) organoid culture, serving as a representative model of SG for the investigation of ALA-PDT.

RESULTS

The h‑tert immortalized sebocyte cell line exhibited the ability to be consecutively cultured for more than fifty passages. Both primary and immortalized cells expressed sebocyte markers such as epithelial membrane antigens (EMA, or MUC-1), Cytokeratin 7 (CK7) and adipose differentiation-related protein associated antigens (ADRP), and maintained sebum secretion function. The proliferative capacity of XL-i-20 was found to be significantly higher than that of primary sebocytes. The responses of XL-i-20 to ALA-PDT were indistinguishable from those elicited by primary sebocytes. Cell viability and sebum secretion were decreased after ALA-PDT in both two cell lines, and lipid-related proteins (SREBP-1/PPARγ) were down-regulated. The transcriptome data consistently demonstrated upregulation of genes related to inflammatory responses and downregulation of genes involved in lipid metabolism in both cell types following PDT. The analysis of common differential genes of primary sebocytes and XL-i-20 sebocytes post ALA-PDT showed that TNF signaling pathways, MAPK signaling pathways and JAK-STAT signaling pathways were activated. The SG organoids were spherical, which expressed markers of FANS and PLET1. Ki-67 was down-regulated after ALA-PDT.

CONCLUSIONS

We have developed an h‑tert immortalized sebocyte cell line from an Asian population. The cell line, XL-i-20, maintains the essential characteristics of its parent primary sebocytes. Moreover, XL-i-20 sebocyte exhibited a significant respond to ALA-PDT, demonstrating comparable phenotypic and molecular changes to primary sebocytes. Therefore, XL-i-20 and its derived SG organoid serve as appropriate in vitro models for investigating the efficacy and mechanisms of ALA-PDT in SG-related diseases.

The use of photodynamic therapy in medical practice

Cancer therapy, especially for tumors near sensitive areas, demands precise treatment. This review explores photodynamic therapy (PDT), a method leveraging photosensitizers (PS), specific wavelength light, and oxygen to target cancer effectively. Recent advancements affirm PDT's efficacy, utilizing ROS generation to induce cancer cell death. With a history spanning over decades, PDT's dynamic evolution has expanded its application across dermatology, oncology, and dentistry. This review aims to dissect PDT's principles, from its inception to contemporary medical applications, highlighting its role in modern cancer treatment strategies.

In Vitro Antimicrobial Photodynamic Therapy for Pseudomonas aeruginosa (P. aeruginosa) and methicillin-resistant Staphylococcus aureus (MRSA) Inhibition Using a Green Light Source

Photodynamic therapy (PDT) has been based on using photosensitizers (PS) and applying light of a specific wavelength. When this technique is used for treating infections, it is known as antimicrobial photodynamic therapy (aPDT). Currently, the use of lighting sources for in vitro studies using aPDT is generally applied in multiwell cell culture plates; however, depending on the lighting arrangement, there are usually errors in the application of the technique because the light from a well can affect the neighboring wells or it may be that not all the wells are used in the same experiment. In addition, one must be awarded high irradiance values, which can cause unwanted photothermal problems in the studies. Thus, this manuscript presents an in vitro antimicrobial photodynamic therapy for a Pseudomonas aeruginosa (P. aeruginosa) and methicillin-resistant Staphylococcus aureus (MRSA) inhibition study using an arrangement of thermally isolated and independently illuminated green light source systems for eight tubes in vitro aPDT, determining the effect of the following factors: (i) irradiance level, (ii) exposure time, and (iii) Rose Bengal (RB) concentration (used as a PS), registering the Pseudomonas aeruginosa (P. aeruginosa) and methicillin-resistant Staphylococcus aureus (MRSA) inhibition rates. The results show that in the dark, RB had a poor antimicrobial rate for P. aeruginosa, finding the maximum inhibition (2.7%) at 30 min with an RB concentration of 3 µg/mL. However, by applying light in a correct dosage (time × irradiance) and the adequate RB concentration, the inhibition rate increased by over 37%. In the case of MRSA, there was no significant inhibition with RB in complete darkness and, in contrast, the rate was 100% for those experiments that were irradiated.

Low-dose oral isotretinoin in the treatment of recalcitrant facial flat warts: A clinical case and review of literature

Background and Aims

The treatment of recalcitrant facial flat warts has always been challenging for dermatologists. The pain related to the application of the different treatments, side effects and costs are determining factors in the choice of therapy. To date, it is known that oral isotretinoin administered at a dose of 0.5 mg/kg/day is effective and safe; However, the different adverse effects reported have a dose-dependent behavior and they could limit their use. Our aim is to assess the effect of low-doses of oral isotretinoin to reducing side effects in the complete removal of recalcitrant facial flat warts and the current evidence in this regard.

Methods

An extensive literature review was conducted to identify articles relating to low doses of oral isotretinoin for recalcitrant flat warts treatment, regardless of design up to May 2023.

Results

The literature search yielded eight articles of 324 reviewed meeting criteria. Isotretinoin was administered in doses of 0.1-0.5 mg/kg/day. Complete elimination of the lesions occurred in 65.13% of the patients and a partial response in 19.26%. Four relapses were documented at the 4-month follow-up. The most frequent adverse effect was cheilitis.

Conclusion

We might consider low doses of oral isotretinoin for the treatment of recalcitrant facial flat warts in which side effects need to be reduced. However, current published works have several limitations, including small sample sizes, lack of control group and follow-up periods. Larger, randomized, controlled studies are needed to verify the efficacy and safety of different doses of isotretinoin.

Effect of 5-Aminolevulinic Acid Photodynamic Therapy on Aspergillus fumigatus Biofilms in Vitro

Aspergillus fumigatus biofilm development results in enhanced pathogenicity and treatment resistance. Most contemporary antibiotics, however, are unable to eliminate biofilms. In recent years, with the application of new photosensitizers and the development of treatment, ALA-PDT (5-aminolevulinic acid photodynamic treatment) has achieved remarkable curative effect in the treatment of fungal infectious diseases; however, no research has been conducted on ALA-PDT against A. fumigatus. This study investigated the inhibitory effect of ALA-PDT at various 5-aminolevulinic acid concentrations and light doses on A. fumigatus planktonic and biofilms in vitro. We found that ALA-PDT may successfully inhibit the development of A. fumigatus biofilm and disintegrate mature biofilm. After ALA-PDT treatment, the adherence rate and vitality dramatically decreased, and the biofilm's structure was severely compromised. Our findings show for the first time that ALA-PDT may be used to prevent the formation of A. fumigatus biofilm and disturb the structure of mature biofilm, and that it could be employed as a therapeutic therapy for A. fumigatus superficial infection.

Partially clustered designs for clinical trials: Unifying existing designs using consistent terminology

INTRODUCTION

Clinical trial designs based on the assumption of independent observations are well established. Clustered clinical trial designs, where all observational units belong to a cluster and outcomes within clusters are expected to be correlated, have also received considerable attention. However, many clinical trials involve partially clustered data, where only some observational units belong to a cluster. Examples of such trials occur in neonatology, where participants include infants from both singleton and multiple births, and ophthalmology, where one or two eyes per participant may need treatment. Partial clustering can also arise in trials of group-based treatments (e.g. group education or counselling sessions) or treatments administered individually by a discrete number of health care professionals (e.g. surgeons or physical therapists), when this is compared to an unclustered control arm. Trials involving partially clustered data have received limited attention in the literature and the current lack of standardised terminology may be hampering the development and dissemination of methods for designing and analysing these trials.

METHODS AND EXAMPLES

In this article, we present an overarching definition of partially clustered trials, bringing together several existing trial designs including those for group-based treatments, clustering due to facilitator effects and the re-randomisation design. We define and describe four types of partially clustered trial designs, characterised by whether the clustering occurs pre-randomisation or post-randomisation and, in the case of pre-randomisation clustering, by the method of randomisation that is used for the clustered observations (individual randomisation, cluster randomisation or balanced randomisation within clusters). Real life examples are provided to highlight the occurrence of partially clustered trials across a variety of fields. To assess how partially clustered trials are currently reported, we review published reports of partially clustered trials.

DISCUSSION

Our findings demonstrate that the description of these trials is often incomplete and the terminology used to describe the trial designs is inconsistent, restricting the ability to identify these trials in the literature. By adopting the definitions and terminology presented in this article, the reporting of partially clustered trials can be substantially improved, and we present several recommendations for reporting these trial designs in practice. Greater awareness of partially clustered trials will facilitate more methodological research into their design and analysis, ultimately improving the quality of these trials.

Effective fluence and dose at skin depth of daylight and lamp sources for PpIX-based photodynamic therapy

SIGNIFICANCE

Skin-based photodynamic therapy (PDT) is used for the clinical treatment of actinic keratosis (AKs) and other skin lesions with continued expansion into the standard of care. Due to the spectral dependency of photosensitizer activation and skin optical fluence, there is a need for more accurate methods to estimate the delivered dose at depth from different PDT light sources and treatment regimens.

AIM

Develop radiometric methods for calculating photosensitizer-effective fluence and dose at depth and determine differences between red-lamp, blue-lamp, and daylight-based PDT treatments.

METHODS

Radiometric measurements of FDA-approved PDT lamp sources, outdoor daylight, and indoor daylight were performed for clinically relevant AK treatments. The protoporphyrin IX (PpIX) equivalent irradiance, fluence, and dose for each light source were calculated from the PpIX absorption spectrum and a 7-layer skin fluence model. The effective fluence and dose at depth was estimated by combining the spectral attenuation predicted at each wavelength and depth with the source fluence at each wavelength.

RESULTS

The red-lamp source had the highest illuminance (112,000 lumen/m²), but lowest PpIX-effective irradiance (9.6 W/m²), and highest effective fluence at depth (10.8 W/m² at 500 µm). In contrast, the blue light source had the lowest illuminance (2300 lumen/m²), but highest PpIX effective irradiance (37.0 W/m²), and ultimately the lowest effective fluence at depth (0.18 W/cm² at 500 µm). The daylight source had values of (outdoor | indoor) illuminance of (49,200 | 37,800 lumen/m²), effective irradiance of (19.2 | 10.7 W/m²), and effective fluence of (1.50 | 1.08 W/m² at 500 µm). The effective fluence and dose at depth facilitated the comparison of treatment regimens, for example, calculating an equivalent dose for a 2 hr indoor daylight treatment and a 10 min red-light treatment for the 300-1000 μm depth range.

CONCLUSIONS

The consideration of PpIX-effective fluence at varying depths is necessary to provide adequate comparisons of the delivered dose from PDT light sources. Methods for calculating radiometric fluence and delivered dose at depth were introduced, with open source MATLAB code, to help overcome the limitations of commonly used photometric and irradiance-based reporting.

The application of photodynamic therapy in plastic and reconstructive surgery

Photodynamic therapy (PDT) is a modern clinical treatment paradigm with the advantages of high selectivity, non-invasiveness, rare side-effect, no obvious drug resistance and easy combination with other therapies. These features have endowed PDT with high focus and application prospects. Studies of photodynamic therapy have been expanded in a lot of biomedical and clinical fields, especially Plastic and Reconstructive Surgery (PRS) the author major in. In this review, we emphasize the mechanism and advances in PDT related to the PRS applications including benign pigmented lesions, vascular malformations, inflammatory lesions, tumor and others. Besides, combined with clinical data analysis, the limitation of PDT and current issues that need to be addressed in the field of PRS have also been discussed. At last, a comprehensive discussion and outlooking represent future progress of PDT in PRS.

Tissue Engineering and Photodynamic Therapy: A New Frontier of Science for Clinical Application -An Up-To-Date Review

Tissue engineering (TE) connects principles of life sciences and engineering to develop biomaterials as alternatives to biological systems and substitutes that can improve and restore tissue function. The principle of TE is the incorporation of cells through a 3D matrix support (scaffold) or using scaffold-free organoid cultures to reproduce the 3D structure. In addition, 3D models developed can be used for different purposes, from studies mimicking healthy tissues and organs as well as to simulate and study different pathologies. Photodynamic therapy (PDT) is a non-invasive therapeutic modality when compared to conventional therapies. Therefore, PDT has great acceptance among patients and proves to be quite efficient due to its selectivity, versatility and therapeutic simplicity. The PDT mechanism consists of the use of three components: a molecule with higher molar extinction coefficient at UV-visible spectra denominated photosensitizer (PS), a monochromatic light source (LASER or LED) and molecular oxygen present in the microenvironment. The association of these components leads to a series of photoreactions and production of ultra-reactive singlet oxygen and reactive oxygen species (ROS). These species in contact with the pathogenic cell, leads to its target death based on necrotic and apoptosis ways. The initial objective of PDT is the production of high concentrations of ROS in order to provoke cellular damage by necrosis or apoptosis. However, recent studies have shown that by decreasing the energy density and consequently reducing the production of ROS, it enabled a specific cell response to photostimulation, tissues and/or organs. Thus, in the present review we highlight the main 3D models involved in TE and PS most used in PDT, as well as the applications, future perspectives and limitations that accompany the techniques aimed at clinical use.

Photodynamic Therapy Review: Principles, Photosensitizers, Applications, and Future Directions

Photodynamic therapy (PDT) is a minimally invasive therapeutic modality that has gained great attention in the past years as a new therapy for cancer treatment. PDT uses photosensitizers that, after being excited by light at a specific wavelength, react with the molecular oxygen to create reactive oxygen species in the target tissue, resulting in cell death. Compared to conventional therapeutic modalities, PDT presents greater selectivity against tumor cells, due to the use of photosensitizers that are preferably localized in tumor lesions, and the precise light irradiation of these lesions. This paper presents a review of the principles, mechanisms, photosensitizers, and current applications of PDT. Moreover, the future path on the research of new photosensitizers with enhanced tumor selectivity, featuring the improvement of PDT effectiveness, has also been addressed. Finally, new applications of PDT have been covered.

Boosting 5-ALA-based photodynamic therapy by a liposomal nanomedicine through intracellular iron ion regulation

5-Aminolevulinic acid (5-ALA) has been approved for clinical photodynamic therapy (PDT) due to its negligible photosensitive toxicity. However, the curative effect of 5-ALA is restricted by intracellular biotransformation inactivation of 5-ALA and potential DNA repair of tumor cells. Inspired by the crucial function of iron ions in 5-ALA transformation and DNA repair, a liposomal nanomedicine (MFLs@5-ALA/DFO) with intracellular iron ion regulation property was developed for boosting the PDT of 5-ALA, which was prepared by co-encapsulating 5-ALA and DFO (deferoxamine, a special iron chelator) into the membrane fusion liposomes (MFLs). MFLs@5-ALA/DFO showed an improved pharmaceutical behavior and rapidly fused with tumor cell membrane for 5-ALA and DFO co-delivery. MFLs@5-ALA/DFO could efficiently reduce iron ion, thus blocking the biotransformation of photosensitive protoporphyrin IX (PpIX) to heme, realizing significant accumulation of photosensitivity. Meanwhile, the activity of DNA repair enzyme was also inhibited with the reduction of iron ion, resulting in the aggravated DNA damage in tumor cells. Our findings showed MFLs@5-ALA/DFO had potential to be applied for enhanced PDT of 5-ALA.

Non-Oncologic Applications of Nanomedicine-Based Phototherapy

Phototherapy is widely applied to various human diseases. Nanomedicine-based phototherapy can be classified into photodynamic therapy (PDT) and photothermal therapy (PTT). Activated photosensitizer kills the target cells by generating radicals or reactive oxygen species in PDT while generating heat in PTT. Both PDT and PTT have been employed for treating various diseases, from preclinical to randomized controlled clinical trials. However, there are still hurdles to overcome before entering clinical practice. This review provides an overview of nanomedicine-based phototherapy, especially in non-oncologic diseases. Multiple clinical trials were undertaken to prove the therapeutic efficacy of PDT in dermatologic, ophthalmologic, cardiovascular, and dental diseases. Preclinical studies showed the feasibility of PDT in neurologic, gastrointestinal, respiratory, and musculoskeletal diseases. A few clinical studies of PTT were tried in atherosclerosis and dry eye syndrome. Although most studies have shown promising results, there have been limitations in specificity, targeting efficiency, and tissue penetration using phototherapy. Recently, nanomaterials have shown promising results to overcome these limitations. With advanced technology, nanomedicine-based phototherapy holds great potential for broader clinical practice.

Topical and systemic retinoids for the treatment of cutaneous viral warts: A systematic review and meta-analysis

Cutaneous viral warts (CVW), caused by human papillomavirus, often have a self-limited course. However, some patients experience a recalcitrant disease despite treatment. Retinoids are considered the mainstay of therapy in many dermatologic diseases. Data on their use for viral warts are limited. To systematically review the published evidence on the efficacy and safety of retinoids for the treatment of CVW. A systematic review and meta-analysis of topical or systemic retinoid treatment for CVW was performed in accordance with the PRISMA statement. The primary outcome was clinical response; secondary outcomes were recurrence rate and adverse events. Fourteen publications including 399 patients treated exclusively with retinoids (65% topical, 35% systemic) were evaluated. The complete response rate was 64% (95% CI, 46-78%; I² =80%) for topical treatment and 61% (95% CI, 44-76%; I² =69%) for systemic treatment. The most common side effects were irritant contact dermatitis and cheilitis, respectively. Relapse rates were 6% and 17%, respectively. The reviewed studies were considerably heterogenous and most lacked a control group. Both topical and systemic retinoids are effective and safe as monotherapy for CVW. Further studies are required to determine their exact role in this setting.

The Quadrivalent Human Papillomavirus Vaccine in Recalcitrant Acral Warts: A Retrospective Study

Introduction: The human papillomavirus (HPV) vaccine has been reported to lead to clinical clearance of lesions when used as an off-label treatment for recalcitrant extragenital warts. The aim of the study is to evaluate the therapeutic and adverse effects of HPV vaccine as an adjunctive therapy for treatment-resistant acral warts. Methods: Patients with persistent warts despite first and second line therapies, and subsequently receiving the quadrivalent HPV vaccine between July 2013 and June 2016 as an adjunctive treatment for recalcitrant warts at the National Skin Centre, were included. Results: Twenty-six patients with a median age of 34 years (range 8 to 77 years) were treated with the HPV vaccine. Nineteen (73.1%) patients completed 3 doses of the vaccine, of whom 5 (26%) achieved complete clearance, 8 (42%) had partial clearance and 6 (32%) did not respond to the vaccine. Among the 4 patients who received 2 doses of the vaccine, 3 (75%) had complete clearance whereas 1 (25%) had partial improvement of their warts. None of the patients reported adverse reactions. Conclusion: Our study suggests a potential adjunctive role of the HPV vaccine in the treatment of acral warts recalcitrant to conventional therapy. Keywords: Acral warts, HPV vaccine, quadrivalent vaccine, recalcitrant warts

The application of medical scale in the treatment of plantar warts: analysis and prospect

Plantar warts are common cutaneous diseases on the sole caused by the human papillomavirus, with a high annual incidence rate of 14%. It often causes pain, which impairs quality of life of patients. Numerous therapeutic options for plantar warts exist with variable success. However, all of them, including first-line treatment, have different adverse reactions or high recurrence rates. There is no one effective method for all patients. The choice of treatment method puzzles doctors. With the help of medical scales, we can analyze the patients' condition, so as to guide the choice of treatment methods, which is of great significance for the individualized treatment of patients with plantar warts. This review takes cryotherapy, intralesional injection of bleomycin and photodynamic therapy as examples to discuss the application of medical scales in the treatment of plantar warts, summarizes the scales that can be used to evaluate the status of plantar wart, adverse reactions, prognosis and patient's financial situation, and discusses their clinical and scientific value. We hope to use scales to consider the severity of plantar warts and economic level, help different patients to choose different treatment options, and make suggestions on the evaluation of the adverse reactions and treatment effect.

A Critical Reappraisal of Off-Label Use of Photodynamic Therapy for the Treatment of Non-Neoplastic Skin Conditions

BACKGROUND

In the past 30 years, topical photodynamic therapy (PDT) has been investigated for the treatment of a broad spectrum of cosmetic, inflammatory, and infectious skin conditions with variable, and often contrasting, results. However, the non-expert clinician may be in difficulty evaluating these results because different sensitizers, concentrations, formulations, light sources, and irradiation protocols have been used. In addition, many of these studies have poor quality design being case reports and uncontrolled studies of few cases.

SUMMARY

With the aim to clarify the potential usefulness of PDT for the treatment of infectious and inflammatory skin diseases as well as selected cosmetic indications, we searched for randomized controlled clinical trials, non-randomized comparative studies, retrospective studies, and case series studies with a number of at least 10 patients, published since 1990. Later, we reappraised the results in order to give a simple critical overview. Key Messages: Evidence from the literature seems to strongly support the use of ALA- and MAL-PDT for the treatment of common skin diseases such as acne, warts, condylomata, and Leishmania skin infection and for photorejuvenation, i.e., the correction of selected cosmetic changes of aging and photoaging. For other disorders, the level of evidence and strength of recommendation are lower, and controlled randomized studies with prolonged follow-ups are necessary in order to assess the clinical usefulness and other potential advantages over current treatment options.

A comprehensive review of treatment options for recalcitrant nongenital cutaneous warts

Introduction: The treatment of recalcitrant nongenital cutaneous warts has always been challenging for dermatologists as they often recur and relapse. Multiple treatment options have been investigated to improve the outcome. This review provides an overview of the current treatment modalities and summarizes the efficacy and side effects of each treatment option for recalcitrant nongenital cutaneous warts.Methods: A PubMed search was performed through July 2019 to include all English language reports investigating the treatment for recalcitrant nongenital cutaneous warts, regardless of design.Results: A total of 144 studies were included in this review. The treatment options for recalcitrant nongenital cutaneous warts can be divided into three groups: destructive treatment, immunotherapy, and cytotoxic agents. Although both destructive therapies and cytotoxic agents demonstrated high complete response rates, immunotherapy, which is a minimally invasive method, was superior in terms of the clearance of distant warts. Intralesional mumps-measles-rubella injections and purified protein derivatives currently demonstrate high efficacy with well-established clinical evidence.Conclusions: Many upcoming treatment modalities, especially immunotherapy, are promising. However, more comparative studies are required to verify the efficacy and safety profile.

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.

Trends and targets in antiviral phototherapy

Photodynamic therapy (PDT) is a well-established treatment option in the treatment of certain cancerous and pre-cancerous lesions. Though best-known for its application in tumor therapy, historically the photodynamic effect was first demonstrated against bacteria at the beginning of the 20^th century. Today, in light of spreading antibiotic resistance and the rise of new infections, this photodynamic inactivation (PDI) of microbes, such as bacteria, fungi, and viruses, is gaining considerable attention. This review focuses on the PDI of viruses as an alternative treatment in antiviral therapy, but also as a means of viral decontamination, covering mainly the literature of the last decade. The PDI of viruses shares the general action mechanism of photodynamic applications: the irradiation of a dye with light and the subsequent generation of reactive oxygen species (ROS) which are the effective phototoxic agents damaging virus targets by reacting with viral nucleic acids, lipids and proteins. Interestingly, a light-independent antiviral activity has also been found for some of these dyes. This review covers the compound classes employed in the PDI of viruses and their various areas of use. In the medical area, currently two fields stand out in which the PDI of viruses has found broader application: the purification of blood products and the treatment of human papilloma virus manifestations. However, the PDI of viruses has also found interest in such diverse areas as water and surface decontamination, and biosafety.

Efficacy of the combination of superficial shaving with photodynamic therapy for recalcitrant periungual warts

BACKGROUND

Periungual warts are a viral infectious disease that occurs in a particular location. It is difficult to eliminate completely, and recurrence is common. Photodynamic therapy (PDT) as an option that has been widely recommended to treat viral warts. However, there are always a few patients with poor efficacy after PDT treatment. We have considered that the reason is the limitation of PDT penetrating deep into tissue. Thus, we combined superficial shaving with PDT to treat recalcitrant periungual warts.

METHODS

Twenty-three patients had a total of 61 periungual wart lesions. All patients had recalcitrant periungual warts that had failed to respond to various treatments that had poor curative effects. After local injection of anesthesia, the lesions were shaved in situ, and PDT was performed immediately. A total of three sessions of PDT were applied for each patient after only one superficial shaving. The overall clinical response rate, recurrence rates, cosmetic outcomes, adverse events, patient satisfaction and quality of life were assessed. The potential risk factors have also been recorded.

RESULTS

We achieved a 96% success rate (defined as more than 50% on clearance) in our 23 patients using combination superficial shaving with PDT after treatment for 3 months. At the 12-month follow-up, 21 patients (91%) had excellent cosmetic outcomes. All patients had satisfactory therapeutic effects and significant improvement in the quality of life. Pain during the illumination process was the main adverse event, but all patients were able to tolerate it. We also found that frequent or continuous hand activity, such as playing Mah-jong, may be a potential risk factor for periungual warts.

CONCLUSION

Our results offer promise for combining superficial shaving with PDT as an effective and safe therapy for patients with periungual warts, especially for those periungual warts that are recurrent, have multiple lesions, and thickness corneum stratum of lesions. For nails that are not suitable for routine surgery, combined superficial shaving with PDT is recommended.

A combination of 2940-nm laser and photodynamic therapy for treatment of recalcitrant facial flat warts

BACKGROUND

Photodynamic therapy (PDT) is one of the treatment options for generalized facial flat warts, which results in elimination of virus and inhibition of proliferation of warts due to photochemical and phototoxic reactions. In this research, we attempted to evaluate the efficacy and safety profiles of a combination of 2940-nm laser and PDT for the treatment of generalized recalcitrant facial flat warts.

METHODS

Retrospective analysis of the patients with recalcitrant facial warts was performed. Patients in the combined group (n = 40) were treated with a 2940-nm single spot abrasion followed by a PDT; while the PDT group (n = 40) received a PDT treatment only. The efficacy was assessed by the lesion numbers and lesion clearance rate. The effective rate was calculated with the cured and excellent response rates.

RESULTS

The combined group showed significant improvements in the total effective rate (77.5%vs. 57.5%, p = 0.0416) and average clearance rate (81.68±2.83% vs. 68.13 ± 3.97%, p = 0.0068) as compared with the PDT-only group. The degree of lesion clearance was positively correlated with the treatment times in both groups. After three months of follow-up, no relapse occurred in patients from either group. Furthermore, an accumulation of photosensitizer in the lesional areas was observed in the combined treatment group.

CONCLUSIONS

A combination of 2940-nm laser and PDT was safe and showed significantly more effect than PDT alone in treatment for recalcitrant facial flat warts, partially due to the improved uptake of photosensitizer after 2940-nm laser induced skin abrasion.

Efficacy and Tolerability of Topical Green Tea Extract (Polyphenon E) Application in a "Therapy-Resistant" Plantar Wart

Plantar warts account for 30% of all cutaneous warts. These lesions could be very painful, especially if the lesion is located over pressure sites such as the metatarsal head. Plantar wart treatment remains a challenging therapeutic problem. A 67-year-old immunocompetent nonsmoking man presented with a large mosaic plantar wart on his right foot. The lesion had been present for 5 years. Several cryotherapy sessions (a total of 6 procedures) had been performed with no success. The lesion was therefore treated with a 5-fluorouracil (5-FU) regimen and then with a topical combination of 5-FU and salicylic acid, but also these approaches failed. At the initial visit, a large (16 cm²) mosaic wart lesion was present. Treatment with topical Polyphenon E, 10%, twice daily was prescribed and started. After 3 months of treatment, the lesion completely disappeared. Interestingly, no curettage or mechanical pickling of the hyperkeratotic parts of the lesion were performed before the start of the treatment. Local tolerability was evaluated as very good by the patient.

The background and philosophy behind daylight photodynamic therapy

Conventional photodynamic therapy (PDT) is associated with side effects, primarily related to the waiting time between pretreatment with application of photosensitizer and illumination. Pain during illumination is a major issue for the patients and options for effective pain relief are limited. Post-treatment inflammation can often be severe and cause inconvenient down-time for the patients and their employers. To avoid the problems of pain and patients crowding in the clinic we eliminated red light treatment of high PpIX concentration and introduced illumination in daylight which may be performed at home. We also investigated if protoporphyrin IX (PpIX) could be activated continuously during its formation which might reduce pain and inflammation. Continuous activation of PpIX during its formation turned out to minimize pain as single PpIX molecules are activated continuously without accumulation of PpIX in the skin. PpIX molecules are formed in the mitochondria and the photodynamic effect only takes place in the mitochondria when continuously activated. This results primarily in apoptosis with little inflammation. Continuous activation of PpIX can be obtained by performing photodynamic therapy in daylight, as well as with daylight-emitting light sources of appropriate wavelengths. Use of daylight prevents the patients from crowding in the clinic. Daylight-PDT completely fulfils the purpose of minimizing pain and inflammation, as well as limiting the strain on the clinic treating the patients.

Therapeutic management of cutaneous and genital warts

During their lifetime, at least 10 % of the population will be infected by human papillomaviruses (HPV), clinically characterized by the formation of cutaneous or genital warts. Although warts are ubiquitous, there are no defined treatments. Especially in the first six months, warts frequently resolve without therapeutic intervention. This complicates the interpretation of study data, given that many studies do not differentiate between newly infected patients and those with infections that have persisted for a long time. Similarly, most studies do not take location, size, and thickness of lesions into account, either. The objective of the present review article is to analyze the study data currently available, taking into consideration both subtypes and locations - factors exceedingly crucial in clinical practice. In particular, the distinction between new-onset and chronic recalcitrant warts is reflected in a therapeutic algorithm. In the case of genital warts, the algorithm is more clearly determined by the extent of the area affected rather than the longevity of lesions. In immunocompetent individuals, any therapeutic intervention must be aimed at achieving complete resolution.

Activating TiO2 Nanoparticles: Gallium-68 Serves as a High-Yield Photon Emitter for Cerenkov-Induced Photodynamic Therapy

The classical photodynamic therapy (PDT) requires external light to activate photosensitizers for cancer treatment. However, limited tissue penetration of light has been a long-standing challenge for PDT to cure malignant tumors in deep tissues. Recently, Cerenkov radiation (CR) emitted by radiotracers such as ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) has become an alternative and promising internal light source. Nevertheless, fluorine-18 (F-18) only releases 1.3 photons per decay in average; consequently, injection dose of F-18 goes beyond 10-30 times more than usual to acquire therapeutic efficacy because of its low Cerenkov productivity. Gallium-68 (Ga-68) is a favorable CR source owing to its ready availability from generator and 30-time higher Cerenkov productivity. Herein, we report, for the first time, the use of Ga-68 as a CR source to activate dextran-modified TiO₂ nanoparticles (D-TiO₂ NPs) for CR-induced PDT. Compared with ¹⁸F-FDG, ⁶⁸Ga-labeled bovine serum albumin (⁶⁸Ga-BSA) inhibited the growth of 4T1 cells and exhibited significantly stronger DNA damage to tumor cells. In vivo studies showed that the tumor growth was almost completely inhibited when tumor-bearing mice were treated with a combination of D-TiO₂ NPs and ⁶⁸Ga-BSA. This study proved that Ga-68 is a more potent radionuclide for PDT than F-18 both in vitro and in vivo offered a promising strategy of using a diagnostic dose of radioactivity to achieve depth-independent cancer therapy without using any external light source.

Efficacy of topical administration of Radix Euphorbiae Ebracteolatae on multiple plantar warts: A parallel randomized trial

OBJECTIVE

To investigate the clinical efficacy of Radix Euphorbiae Ebracteolatae in treating multiple plantar warts.

METHODS

Twenty-eight patients with multiple plantar warts on both left and right feet were recruited. Warts on the left feet (treatment group) of all patients were externally treated with moderate ethanol extract of Radix Euphorbiae Ebracteolatae which was made of 30 g Radix Euphorbiae Ebracteolatae putting into 100 mL of medical ethanol (75%). For the control group, moderate dose of 0.1% vitamin A acid ointment was externally applied onto the right-foot warts. The topical application of each treatment was conducted 3 times a day for both groups. After 4 and 8 weeks, the efficacy and side effects including skin erythema and blister were evaluated and observed.

RESULTS

Compared with the pre-treatment, warts size of the control group was reduced after 8-week treatment (P<0.05). After 4 and 8 weeks, the average wart size in the treatment group was both significantly reduced respectively (P<0.01). There were significant differences in warts size and total effective rate between the two groups after 4-week treatment respectively (P<0.05 or P<0.01). More significant differences in wart size and total effective rate were observed after 8-week treatment (P<0.05 or P<0.01). The percentage reduction in wart size was significantly different between the two groups after 4 and 8-week treatment (P<0.01).

CONCLUSION

Radix Euphorbiae Ebracteolatae was significantly superior to vitamin A acid ointment in treating multiple plantar warts.

Photodynamic Therapy: A Clinical Consensus Guide

BACKGROUND

The American Society of Dermatologic Surgery (ASDS) periodically develops consensus documents for its members concerning various aspects of dermatologic surgery. Advances in photodynamic therapy (PDT) have been many and PDT use has been established in a variety of skin conditions.

OBJECTIVE

The ASDS board of directors proposed a committee of experts in the field to develop consensus documents on different treatments. An expert panel reviewed the literature on PDT and discussed the findings. The consensus was reached with evidence-based recommendations on different clinical applications for PDT.

PATIENTS AND METHODS

This consensus document includes discussions regarding PDT, including different photosensitizers and various light source activators, historical perspective, mechanism of action, various therapeutic indications and expected outcomes, pre- and post-care, and management of adverse outcomes.

RESULTS

Photodynamic therapy is highly effective for pre-cancerous lesions, superficial nonmelanoma skin cancers, inflammatory acne vulgaris and other conditions. New protocols including laser mediated PDT significantly improve results for several indications.

CONCLUSION

The ASDS consensus document on PDT will be helpful for educating members on safe and effective PDT for a variety of indications.

Low-Dose Topical 5-Aminolevulinic Acid Photodynamic Therapy in the Treatment of Different Severity of Acne Vulgaris

The objective of this article is to investigate the effectiveness and safety of photodynamic therapy (PDT) with 3.6 % topical aminolevulinic acid (ALA) and a short incubation time with red light in moderate to severe acne. One hundred and thirty-six patients with moderate to severe acne were treated with 3.6 % topical ALA-PDT for three sessions with an interval of 2 weeks. Patients were evaluated for efficacy and safety on week 2, 4, 6, 8, and 12 after the initial treatment. Most patients showed apparent clearance of acne lesions at the treated site after three sessions. The effective treatment rates were increased after the multiple therapies. The clinical outcomes are the best at 4 weeks after the final treatment. The total effectiveness rate and cure rate of the low-dose ALA-PDT procedure is 92.65 and 47.06 %, respectively. Thirty-one patients and nineteen patients showed apparent exacerbation of acne lesions before the 2nd and 3rd treatment, respectively, but all of them showed good or excellent improvement after a three-course treatment. A few patients showed mild relapse including papules and comedos at 8 weeks after the final treatment. No significant differences are found in the effects of different acne severity and different genders. Adverse reactions are mild and transient. A 3.6 % topical ALA-PDT with a short time incubation with red light is a simple and an effective treatment option for moderate to severe acne with mild side effects in Chinese people.

Multiple Large-Surface Photodynamic Therapy Sessions with Topical or Systemic Aminolevulinic Acid and Blue Light in UV-Exposed Hairless Mice

Background:

The use of photodynamic therapy (PDT) with topical aminolevulinic acid (ALA) on large skin surfaces has recently been reported for patients with multiple actinic keratoses.

Objective:

The current study compared the ability of topical and systemic ALA–PDT as well as topical ALA–PDT with blue light to delay the appearance of UV-induced skin cancer using the hairless mouse as a model.

Methods:

Groups of hairless mice were exposed daily to UV radiation and weekly to ALA–PDT. Tumor-free survival was compared for mice exposed to UV and treated weekly with ALA–PDT and mice exposed only to UV radiation.

Results:

Weekly topical or systemic ALA–PDT was able to delay the induction of skin tumors. A significant difference in tumor-free survival was also observed for both actinic keratoses and invasive squamous cell carcinoma in mice treated weekly with topical ALA–PDT performed with blue light. This was observed even when weekly ALA–PDT was started after 8 weeks of UV exposure.

Conclusion:

Large-surface topical ALA–PDT with blue light can delay the appearance of UV-induced actinic keratoses and squamous cell carcinoma in hairless mice.

Treatment of warts and molluscum: what does the evidence show?

PURPOSE OF REVIEW

Warts and molluscum contagiosum are very common viral skin infections, usually presenting in childhood. Despite the large number of people affected by them, high-quality trials of treatment are few and treatment is often chosen on the basis of cost, convenience and tradition.

RECENT FINDINGS

Over recent years, two further trials of the most commonly used treatments for warts, salicylic acid and cryotherapy, have been performed and for molluscum contagiosum, there is growing evidence for the use of irritants. For both infections, there are new evaluations of immunological approaches to therapy.

SUMMARY

Strong, high-quality evidence for treatments used very frequently for warts or molluscum is still lacking, but recent publications have helped to strengthen or weaken belief in commonly used therapies and to add weight to the immunological approach to management.

In situ production of ROS in the skin by photodynamic therapy as a powerful tool in clinical dermatology

Photodynamic therapy (PDT) is a clinical modality of photochemotherapy based on the accumulation of a photosensitizer in target cells and subsequent irradiation of the tissue with light of adequate wavelength promoting reactive oxygen species (ROS) formation and cell death. PDT is used in several medical specialties as an organ-specific therapy for different entities. In this review we focus on the current dermatological procedure of PDT. In the most widely used PDT protocol in dermatology, ROS production occurs by accumulation of the endogenous photosensitizer protoporphyrin IX after treatment with the metabolic precursors 5-methylaminolevulinic acid (MAL) or 5-aminolevulinic acid (ALA). To date, current approved dermatological indications of PDT include actinic keratoses (AK), basal cell carcinoma (BCC) and in situ squamous cell carcinoma (SCC) also known as Bowen disease (BD). With regards to AKs, PDT can also treat the cancerization field carrying an oncogenic risk. In addition, an increasing number of pathologies, such as other skin cancers, infectious, inflammatory or pilosebaceous diseases are being considered as potentially treatable entities with PDT. Besides the known therapeutic properties of PDT, there is a modality used for skin rejuvenation and aesthetic purposes defined as photodynamic photorejuvenation. This technique enables the remodelling of collagen, which in turn prevents and treats photoaging stygmata. Finally we explore a new potential treatment field for PDT determined by the activation of follicular bulge stem cells caused by in situ ROS formation.

Off-label photodynamic therapy for recalcitrant facial flat warts using topical 5-aminolevulinic acid

The facial flat wart (verruca plana) is one of the most common reasons for dermatology and primary care visits. Although there are many therapeutic modalities, no single therapy has been proven to be completely curative. Case reports and uncontrolled studies suggested that photodynamic therapy (PDT) with topical 5-aminolevulinic acid (ALA) can effectively treat recalcitrant facial flat warts. A total of 12 patients with recalcitrant facial flat warts were enrolled in the study. ALA gel (10 %) was applied topically to lesions and incubated for 3 h. The lesions were irradiated by an LED light of 630 ± 10 nm at dose levels of 60-100 mW/cm. Clinical assessment was conducted before and after every treatment for up to 24 weeks. Among the ten patients completing three sessions of ALA-PDT, five had complete lesions clearance, and the other five patients were significantly improved. At the 24-week follow-up, the average effective rate was 88.8 %, with no recurrences. No significant side effects were reported. A low-dose topical ALA-PDT regimen using 10 % ALA, 3 h incubation, and a red light source for three treatment sessions are suggested as the optimal scheme for the treatment of recalcitrant flat warts on the face in Chinese patients. Superior efficacy is found in elevated or active period lesions with mild side effects.

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.

Photodynamic therapy with topical aminolevulinic acid

Photodynamic therapy (PDT) is a relatively new therapy in dermatology that uses the topical application of a porphyrin derivative to selectively destroy a cutaneous target. The action is implemented by the application of a specific light frequency. The ability of porphyrin to selectively target tumor tissue has been known since the 1960s. In the late 1970s, the underlying mechanism was defined, and Dougherty’s discovery of the first chromophore led to the production and commercialization of Photofrin^®. Many other chromophores that can act as photosensitizers have been studied since then, with aminolevulinic acid currently the most commonly used chromophore in clinical practice. PDT is simple, minimally invasive and can be administered on an outpatient basis. The efficacy of PDT has been proven for actinic keratosis, Bowen’s disease and basal cell carcinoma; another of its well-known applications is the treatment of photoaging. Indications for its use are continuously increasing, and promising results are reported for various skin diseases. In this paper we report the mechanism of action of PDT with aminolevulinic acid, the literature concerning the most common diseases treated with PDT and the subsequent level of evidence.