Photodynamic Therapy: Current Evidence and Applications in Dermatology

Comparison of photodynamic therapy and corticosteroid therapy in management of oral lichen planus: A systematic review of randomized controlled trials

INTRODUCTION

Photodynamic therapy (PDT) has emerged as an effective therapy for various dermatology conditions, including oral lichen planus (OLP). The objective of this study was to evaluate the efficacy of PDT in managing OLP and to compare its effectiveness with corticosteroid therapy (CST).

MATERIALS AND METHODS

A comprehensive electronic search was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, utilizing databases such as PubMed, Embase, Google Scholar, Semantic Scholar, X-mole, and Dimensions. The inclusion criteria encompassed randomized controlled clinical trials (RCTs) that included patients with OLP undergoing treatment with PDT and CST, with no limitations on sample size or patient age.

RESULTS

Out of 197 studies identified, only 8 met the inclusion criteria, involving 210 patients (104 in Group I: PDT, 106 in Group II: CST), with a female to male ratio of 3.75. Three studies reported OLP lesion numbers, six studies described lesion types, and five studies provided lesion location information. The efficacy of both PDT and CST was assessed using lesion size, pain, Thongprasom sign (ThS) scoring, efficacy index (EI), and clinical severity index (CSI). The limited and inconsistent reporting of data hindered to conduct a meta-analysis.

CONCLUSIONS

PDT effectively treats OLP lesions, leading to significant symptom reduction and improved functionality. However, limited relevant RCTs and heterogeneous data reporting hinder definitive conclusions regarding the efficacy of PDT compared to CTS.

Effects of photodynamic therapy using Red LED-light combined with hypocrellin B on apoptotic signaling in cutaneous squamous cell carcinoma A431 cells

BACKGROUND

The incidence of cutaneous squamous cell carcinoma (cSCC) has been demonstrating yearly increases. cSCC is a malignant cancer and exerts a major impact on patients' health and quality of life. Thus, the development and use of novel therapies in the treatment of cSCC are needed. It has been reported that LED photodynamic therapy (LED PDT) mediated by Hypocrellin B and its derivatives, a second-generation photosensitizer, can induce apoptosis in a variety of tumor cells, However, its potential pro-apoptotic effects on cSCC have yet to be investigated.

OBJECTIVE

This study aims to investigate the pro-apoptotic effects and molecular mechanisms of HB-LED PDT in cutaneous squamous cell carcinoma A431 cells (Subsequent abbreviation A431 cells). Such information can provide an important theoretical foundation for the clinical translation of HB-LED PDT in the treatment of cSCC.

METHODS

1. Effects of HB on A431 cells were determined using a Cell Counting Kit-8 assay, which method can indirectly reflect the number of living cells. In this way, this assay can then provide a means to identify the optimal concentrations of HB required for the induction of apoptosis in A431 cells. 2. The effects of HB-LED PDT on the morphology of A431 cells and changes in the nuclei after Hoechst33342 staining as determined using inverted fluorescent microscopy. 3. Use of the Annexin V-FITC test kit to detect levels of apoptosis in A431 cells in response to treatment with HB. Changes in reactive oxygen species and mitochondrial membrane potential following HB-LED PDT treatment in A431 cells were determined using fluorescence activated cell sorting (FACS). 4. Real-time quantitative PCR and Western Blot were applied to assess changes in several key factors involved in apoptosis including Bax, Bcl-2, and Caspase-3, at both transcription and translation levels. With these assays, it was possible to investigate the apoptotic signaling pathway in A431 cells in response to HB-LED PDT.

RESULTS

HB-LED PDT inhibited proliferation activity and promoted nuclear fragmentation within these A431 cells. HB-LED PDT inhibited mitochondrial activity, increased reactive oxygen species production, and promoted apoptosis of A431 cells. In addition, several key factors in the apoptotic signaling pathway were increased at both the transcriptional and translational levels in A431 cells in response to the HB-LED PDT, indicating that the apoptotic signaling pathway was activated by HB-LED PDT.

CONCLUSION

HB-LED PDT induces apoptosis in A431 cells through a mitochondria-mediated apoptotic pathway. Such findings serve as an important foundation for the development of new approaches in the treatment of cSCC.

Effect of substituents in chlorin e6 derivatives on the loading efficiency of the photosensitizer into the liposome membrane and their biological activity

In this work, we incorporated the hydrophobic alkylamide and hydroxyalkylamide derivatives of chlorin e₆ into the lipid bilayer of liposomes. We obtained the data on the effectiveness of incorporation of studied compounds and have determined the size of liposomes and their stability when stored in liquid form. We also investigated the bioactivity of chlorin photosensitizers and compared the photodynamic activity of studied compounds in free and liposomal forms.

Past, present and future of Focused Ultrasound as an adjunct or complement to DIPG/DMG therapy: A consensus of the 2021 FUSF DIPG meeting

Diffuse Intrinsic Pontine Glioma (DIPG), now known as Diffuse Midline Glioma (DMG) is a devastating pediatric brain tumor with limited treatment options and a very poor prognosis. Despite more than 250 clinical trials aimed to treat children diagnosed with DMG, no curative therapies currently exist for this patient population. A major obstacle has been the intact blood brain barrier (BBB) which prevents most therapeutics from crossing into the tumor bed. Focused Ultrasound (FUS) is an emerging, noninvasive medical technology which has been shown in both preclinical and clinical research to disrupt the blood brain barrier safely and temporarily. FUS blood brain barrier opening has been studied in combination with chemotherapies in preclinical DMG models, and this technology is now being investigated in clinical trials for the treatment of pediatric brain tumors. Focused ultrasound has additional mechanisms of action, including sonodynamic therapy and radiation sensitization, that hold promise as future DMG therapies as well. This paper, largely based off the proceedings from a workshop held by the Focused Ultrasound Foundation in October of 2021, summarizes the current state of the field of focused ultrasound for DIPG/DMG, including preclinical, technical, and clinical summaries in addition to recommended next steps for continued advancement of the game changing technology of Focused Ultrasound.

Amplifying the efficacy of ALA-based prodrugs for photodynamic therapy using nanotechnology

5-aminolevulinic acid (ALA) is a clinically approved prodrug involved in intracellular Heme biosynthesis to produce the natural photosensitizer (PS) Protoporphyrin IX (PpIX). ALA based photodynamic therapy (PDT) has been used to treat various malignant and non-malignant diseases. However, natural ALA has disadvantages such as weak lipophilicity, low stability and poor bioavailability, greatly reducing its clinical performance. The emerging nanotechnology is expected to address these limitations and thus improve the therapeutic outcomes. Herein, we summarized important recent advances in the design of ALA-based prodrugs using nanotechnology to improve the efficacy of PDT. The potential limitations and future perspectives of ALA-based nanomedicines are also briefly presented and discussed.

An Update on Photodynamic Therapy of Psoriasis—Current Strategies and Nanotechnology as a Future Perspective

Psoriasis (PS) is an immune-mediated skin disease with substantial negative effects on patient quality of life. Despite significant progress in the development of novel treatment options over the past few decades, a high percentage of patients with psoriasis remain undertreated and require new medications with superior long-term efficacy and safety. One of the most promising treatment options against psoriatic lesions is a form of phototherapy known as photodynamic therapy (PDT), which involves either the systemic or local application of a cell-targeting photosensitizing compound, followed by selective illumination of the lesion with visible light. However, the effectiveness of clinically incorporated photosensitizers in psoriasis treatment is limited, and adverse effects such as pain or burning sensations are frequently reported. In this study, we performed a literature review and attempted to provide a pooled estimate of the efficacy and short-term safety of targeted PDT in the treatment of psoriasis. Despite some encouraging results, PDT remains clinically underutilized. This highlights the need for further studies that will aim to evaluate the efficacy of a wider spectrum of photosensitizers and the potential of nanotechnology in psoriasis treatment.

Advanced Polymeric Nanoagents for Oral Cancer Theranostics: A Mini Review

Oral cancer is one of the most common tumours in the world threatening human life and health. The 5-years survival rate of patients with oral cancer has not been improved significantly for many years. The existing clinical diagnostic methods rarely achieve early diagnosis due to deficiencies such as lack of sensitivity. Most of the patients have progressed to the advanced stages when oral cancer is detected. Unfortunately, the traditional treatment methods are usually ineffective at this stage. Therefore, there is an urgent need for more effective and precise techniques for early diagnosis and effective treatment of oral cancer. In recent decades, nanomedicine has been a novel diagnostic and therapeutic platform for various diseases, especially cancer. The synthesis and application of various nanoagents have emerged at the right moment. Among them, polymer nanoagents have unique advantages, such as good stability, high biosafety and high drug loading, showing great potential in the early accurate diagnosis and treatment of tumours. In this review, we focus on the application of advanced polymeric nanoagents in both the diagnosis and treatment of oral cancer. Then, the future therapy strategies and trends for polymeric nanoagents applied to oral cancer are discussed, with the hope that more advanced nanomedical technology will be applied to oral cancer research and promote the development of stomatology.

Photodynamic therapy, a promising treatment approach for cutaneous infectious granulomas

Cutaneous infectious granulomas are mainly caused by fungi and bacteria. Antibiotics are the primary therapeutic choices for the diseases, but the drug-resistant pathogens become increasingly prevalent. Thus, there is an urgent need to explore novel approaches to treating cutaneous infectious granulomas. Photodynamic therapy (PDT) is widely used as an alternative treatment for various kinds of skin diseases, and evidence has been accumulating that PDT is also effective for the treatment of cutaneous infectious granulomas. In this narrative review, we sought to summarize the recent literature concerning the applications and mechanisms of PDT in the treatment of cutaneous infectious granulomas. Clinical and basic research has demonstrated that PDT is an effective approach in treating fungal infections such as sporotrichosis and chromoblastomycosis. In addition, PDT is also used to treat atypical mycobacterial infections such as Mycobacterium marinum. PDT can significantly shorten the duration of antibiotics treatment, resulting in diminishment of adverse effects. The potential mechanisms of PDT are to kill the pathogens directly or elicit modulatory effects on the immune microenvironments. We conclude that PDT is a promising therapeutic choice for the treatment of cutaneous infectious granulomas.

Photodynamic Therapy for Treatment of Disease in Children—A Review of the Literature

Photodynamic therapy is a mode of treatment whereby local irradiation of an administered photosensitizer with light of a specific wavelength generates cytotoxic reactive oxygen species. Despite the upward trend in the popularity of this method in adults, it is not yet commonly used in the treatment of children. Due to certain limitations, underdeveloped treatment regimens and potential side effects, the use of photodynamic therapy in the pediatric population is still in the initial phases of evaluation in clinical trials. Method: This study is a review of articles in English from the databases PubMed and Web of Science retrieved by applying the search term “photodynamic therapy in children” from 2000–2020. Results: Based on the literature review, we analyze selected pediatric clinical cases in which photodynamic therapy was used for treatment in children. Examples of photodynamic therapy for treatment of dermatological diseases, diseases of the mucosa of the upper respiratory tract, halitosis, eye diseases and brain tumors are described. The paper describes the effectiveness of anti-cancer photodynamic therapy, including its use in antibacterial therapy. Conclusions: The results of the analysis suggest the potential of photodynamic therapy for the treatment of various diseases in children.

Phototherapy and optical waveguides for the treatment of infection

With rapid emergence of multi-drug resistant microbes, it is imperative to seek alternative means for infection control. Optical waveguides are an auspicious delivery method for precise administration of phototherapy. Studies have shown that phototherapy is promising in fighting against a myriad of infectious pathogens (i.e. viruses, bacteria, fungi, and protozoa) including biofilm-forming species and drug-resistant strains while evading treatment resistance. When administered via optical waveguides, phototherapy can treat both superficial and deep-tissue infections while minimizing off-site effects that afflict conventional phototherapy and pharmacotherapy. Despite great therapeutic potential, exact mechanisms, materials, and fabrication designs to optimize this promising treatment option are underexplored. This review outlines principles and applications of phototherapy and optical waveguides for infection control. Research advances, challenges, and outlook regarding this delivery system are rigorously discussed in a hope to inspire future developments of optical waveguide-mediated phototherapy for the management of infection and beyond.

A rapid antimicrobial photodynamic water treatment strategy utilizing a xanthene dye with subsequent removal by Goethite Nanoparticles

Although widely accepted as a water sterilisation technique, chlorination results in the production of potentially harmful by-products, mainly Trihalomethanes. Furthermore, the chlorination process requires specialised infrastructure, management and high costs. In this research paper a potential alternative sterilisation technique was investigated. This rapid three-step process utilized Goethite Nanoparticles and the photosensitising capabilities of a xanthene dye. Rose Bengal (RB) a compound primarily used as a stain to diagnose damaged tissue in the eye was utilized under visible light excitation to sterilise water containing gram-positive Staphylococcus aureus and Bacillus cereus. Bacterial reductions (cfu/ml) of up to 6log10 are reported at RB concentrations of 0.5 mg/L and 10 mg/L for S. aureus and B. cereus, respectively. Goethite Nanoparticles (GNP's), an iron oxyhydroxide, were synthesised by co-precipitation of iron salts and used to adsorb RB post-sterilisation. Poly-vinyl Alcohol (PVA) functionalised GNP's were synthesised to highlight the adsorbent capabilities of the GNP surface. The adsorption capacity for uncoated GNPs was 476.19 mg/g, this reduced to 170.4 mg/g for PVA-GNP's, highlighting the highly porous nature of the synthesised GNP surface. Adsorption was optimal in slightly acidic conditions (pH5-6). The adsorption parameters best followed Lagergens Pseudo-second order kinetics with correlation coefficients close to unity. At the highest envisaged RB concentration (10 mg/L) approximately 20 mg/L GNP's was required to remove the dye from solution post-treatment. Flame Atomic Absorption analysis of the water post-removal revealed Iron concentrations of 0.058 mg/L. This correlates to removal efficacy of 99.71% with residual iron levels below the EU recommended limit of 0.2 mg/L.

An update in clinical utilization of photodynamic therapy for lung cancer

Lung cancer is one of the leading causes of cancer-related death worldwide, with nearly 1.8 million-diagnosis and 1.59 million deaths. Surgery, radiotherapy, and chemotherapy in individual or combination are commonly used to treat lung cancers. Photodynamic therapy (PDT) is a highly selective method for the destruction of cancer cells by exerting cytotoxic activity on malignant cells. PDT has been the subject of numerous clinical studies and has proven to be an effective strategy for cancer therapy. Clinical studies revealed that PDT could prolong survival in patients with inoperable cancers and significantly improve quality of life. For inoperable lung cancer cases, PDT could be an effective therapy. Despite the clinical success reported, PDT is still currently underutilized to treat lung cancer and other tumors. PTD is still a new treatment approach for lung cancer mainly due to the lack of enough clinical research evaluating its' effectiveness and side effects. In this review, we discuss the current prospects and future potentials of PDT in lung cancer treatment.

Low-level laser therapy for the treatment of early stage cutaneous leishmaniasis: A pilot study

Low-Level Laser Therapy (LLLT) has been investigated for the treatment of various dermatological disorders. Here, we investigate the efficacy of LLLT for the treatment of cutaneous leishmaniasis (CL). This study comprised of 53 patients (total 123 lesions) with a confirmed diagnosis of CL via positive smear of LD-bodies. The CL lesions were classified in Grade I (ie, papule of size ≤1 cm) to Grade V (ie, vesicle formation, ulceration, and superadded infection of size >4 cm). All the patients were divided into group 1 with low grade (ie, Grade I and II) CL lesions and group 2 with high-grade disease (ie, Grade III-V). Red laser light (wavelength = 635 nm) was used for the lesion irradiation, with a light dose of 75 J/cm2 and at a low power of 300 mW. The treatment was divided into four sessions, one session per week. Disease assessment at 10 months follow-up revealed complete response in 91% and partial response in 9% patients of group 1, while no response was observed in patients of group 2. LLLT offers a promising treatment modality for patients presenting with early-stage (ie, Grade I and II) CL lesions.

Platelet-Activating Factor as an Effector for Environmental Stressors

Environmental stressors exert a profound effect on humans. Many environmental stressors have in common the ability to induce reactive oxygen species. The goal of this chapter is to present evidence that the potent lipid mediator platelet-activating factor (PAF) is involved in the effects of many stressors ranging from cigarette smoke to ultraviolet B radiation. These environmental stressors can generate PAF enzymatically as well as PAF-like lipids produced by free radical-mediated attack of glycerophosphocholines. Inasmuch as PAF exerts both acute inflammation and delayed immunosuppressive effects, involvement of the PAF system can provide an explanation for many consequences of environmental stressor exposures.

Photodynamic Therapy for the Treatment of Complex Anal Fistula

BACKGROUND AND OBJECTIVES

To validate and analyze the results of intralesional photodynamic therapy in the treatment of complex anal fistula.

STUDY DESIGN/MATERIALS AND METHODS

This prospective multicentric observational study enrolled patients treated for complex anal fistula who underwent intralesional photodynamic therapy (i-PDT). The included patients were treated from January 2016 to December 2018 with a minimum follow-up of 1 year to evaluate recurrence, continence and postoperative morbidity. Intralesional 5-aminolevulinic acid (ALA) gel (2%) was injected directly into the fistula. The internal and external orifices were closed. After an incubation period of 2 hours, the fistula was irradiated using an optical fiber connected to a red laser (Multidiode 630 PDT) operating at 1 W/cm for 3 minutes (180 J).

RESULTS

In total, 49 patients were included (61.2% male). The mean age was 48 years, and the mean duration of fistula was 13 months. Of the fistulas included, 75.5% were medium transphincteric, and 24.5% were high transphincteric. The median fistula length was 4 ± 1,14 cm (range: 3-5). A total of 41 patients (83.7%) had a previous history of fistula surgery. Preoperatively, some degree of anal incontinence was found in 5 patients (10.2%). No center reported any other procedure-related complications intraoperatively. Phototoxicity was found in one patient. In the first 48 hours after the procedure, fever was reported in 2 patients (4%). At the end of follow-up, total healing was observed in 32/49 patients (65.3%). No patient reported new incontinence postoperatively.

CONCLUSION

i-PDT could be considered a good choice in patients with complex anal fistulas to avoid surgery and its complications. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Chlorin, Phthalocyanine, and Porphyrin Types Derivatives in Phototreatment of Cutaneous Manifestations: A Review

Recent scientific research has shown the use of chlorin, phthalocyanines, and porphyrins derivatives as photosensitizers in photodynamic therapy in the treatment of various pathologies, including some of the major skin diseases. Thus, the main goal of this critical review is to catalog the papers that used these photosensitizers in the treatment of acne vulgaris, psoriasis, papillomavirus infections, cutaneous leishmaniasis, and skin rejuvenation, and to explore the photodynamic therapy mechanisms against these conditions alongside their clinical benefits.

Joint American Academy of Dermatology-National Psoriasis Foundation guidelines of care for the management and treatment of psoriasis with phototherapy

Psoriasis is a chronic inflammatory disease involving multiple organ systems and affecting approximately 3.2% of the world's population. In this section of the guidelines of care for psoriasis, we will focus the discussion on ultraviolet (UV) light-based therapies, which include narrowband and broadband UVB, UVA in conjunction with photosensitizing agents, targeted UVB treatments such as with an excimer laser, and several other modalities and variations of these core phototherapies, including newer applications of pulsed dye lasers, intense pulse light, and light-emitting electrodes. We will provide an in-depth, evidence-based discussion of efficacy and safety for each treatment modality and provide recommendations and guidance for the use of these therapies alone or in conjunction with other topical and/or systemic psoriasis treatments.

A novel pro-apoptotic role of zinc octacarboxyphthalocyanine in melanoma me45 cancer cell's photodynamic therapy (PDT)

Zn-based phthalocyanine acts as drug or photosensitizer in photodynamic therapy (PDT) for the treatment of cancer cells. The activated zinc octacarboxyphthalocyanine (ZnPcOC) reacts with oxygen, to generate reactive oxygen species for the damage of melanoma cancer cells, Me45. This in vitro study aimed at investigating the cytotoxic effects of different concentrations of ZnPcOC activated with a diode laser (λ = 685 nm) on Me45, and normal human fibroblast cells, NHDF. To perform this study 10⁴ cells/ml were seeded in 96-well plates and allowed to attach overnight, after which cells were treated with different concentrations of ZnPcOC (10, 20 and 30 μM). After 4 h, cells were irradiated with a constant light dose of 2.5; 4.5 and 7.5 J/cm². Post-irradiated cells were incubated for 24 h before cell viability was measured using the MTT viability assay. Data indicated that high concentrations of ZnPcOC (30 μM) in its inactive state are not cytotoxic to the melanoma cancer cells and normal fibroblasts. Moreover, the results showed that photoactivated ZnPcOC (30 μM) was able to reduce the cell viability of melanoma and fibroblast to about 50%, respectively. At this photosensitizing concentration the efficacy the treatment light dose of 2.5; 4.5 and 7.5 J/cm² was evaluated against Me45 cells. ZnPcOC at a concentration of 30 μM activated with a light dose of 2.5; 4.5 and 7.5 J/cm² was the most efficient for the killing of melanoma cancer cells. Melanoma cancer cells after PDT with a photosensitizing concentration of 30 μM ZnPcOC and a treatment light dose of 2.5; 4.5 and 7.5 J/cm² showed certain pro-apoptotic characteristics, such as direct inducer (early apoptosis) and long-term inducer, also (late apoptosis). This concludes that low concentrations of ZnPcOC, activated with the appropriate light dose, can be used to induce cell death in melanoma cells via ROS-induces apoptosis pathway, what was confirmed with cytometric ROS measurements. Our in vitro study showed that ZnPcOC mediated photodynamic therapy is an effective treatment option for melanoma Me45 cancer cells. 30 μM of ZnPcOC with the treatment light dose of 2.5 J/cm² from a LED diode laser source, with a wavelength of 685 nm, was adequate to destroy melanoma cancer cells via ROS-induced apoptosis pathway, with low killing effects on healthy NHDF normal fibroblasts.

Assessing Configurational Sampling in the Quantum Mechanics/Molecular Mechanics Calculation of Temoporfin Absorption Spectrum and Triplet Density of States

The absorption properties of Temoporfin, a second-generation photosensitizer employed in photodynamic therapy, are calculated with an electrostatic-embedding quantum mechanics/molecular mechanics (QM/MM) scheme in methanol. The suitability of several ensembles of geometries generated by different sampling techniques, namely classical-molecular-dynamics (MD) and QM/MM-MD thermal sampling, Wigner quantum sampling and a hybrid protocol, which combines the thermal and quantum approaches, is assessed. It is found that a QM description of the chromophore during the sampling is needed in order to achieve a good agreement with respect to the experimental spectrum. Such a good agreement is obtained with both QM/MM-MD and Wigner samplings, demonstrating that a proper description of the anharmonic motions of the chromophore is not relevant in the computation of the absorption properties. In addition, it is also found that solvent organization is a rather fast process and a long sampling is not required. Finally, it is also demonstrated that the same exchange-correlation functional should be employed in the sampling and in the computation of the excited states properties to avoid unphysical triplet states with relative energies close or below 0 eV.

Photodynamic Therapy for the Treatment of American Tegumentary Leishmaniasis: Evaluation of Therapies Association in Experimentally Infected Mice With Leishmania (Leishmania) amazonensis

Introduction: American tegumentary leishmaniasis (ATL) is a zoonotic disease caused by protozoan parasites of the genus Leishmania that affects the skin and mucous membrane. Currently, the available drugs for the treatment are injectable, with side effects, long-term treatment regimen and there is the possibility of drug resistance. Thus, alternative therapies have been tested, including photodynamic therapy (PDT). We evaluated the efficacy of PDT on its own and associated with the prescribed ATL treatment. Methods: BALB/c mice were infected with Leishmania (Leishmania) amazonensis and divided into 6 groups: Gluc+PDT, treated with Glucantime® and photodynamic therapy (PDT) with methylene blue (MB)/red LED (light-emitting diode); Gluc, treated with Glucantime®; PDT, treated with PDT with MB/red LED; Ampho+PDT, treated with amphotericin and PDT with MB/red LED; Ampho, treated with amphotericin; and control, which were infected but not treated. Two treatment cycles were performed. After 165 days of infection, the parasite load was determined. Results: Statistical differences were not found (P>0.05) between measures of volume and thickness of the infected footpads in the treated groups when compared with the control group. However, there was a significant reduction (P<0.05) in the parasitic load of the popliteal lymph nodes of the Gluc+PDT, Gluc, PDT and Ampho groups when compared to the control group. In the histological analysis of the infected footpads, the Gluc+PDT group presented a smaller amount of amastigote nests and lower intensity of the mononuclear infiltrate when compared to the Gluc and PDT groups. Conclusion: The results showed that although there is no significant difference in the evaluations of footpad size (thickness and volume), there is a downward measurement tendency in the Gluc+PDT group, as it can be observed by volume data and corroborated by parasite negative load.

Using X-rays in photodynamic therapy: an overview

Photodynamic therapy is a therapeutic option to treat cancer and other diseases.

Phototoxic effect of aluminium-chlorine and aluminium-hydroxide phthalocyanines on Leishmania (l.) amazonensis

This study investigated the activity of photosensitive phthalocyanines on promastigotes and amastigotes of Leishmania (L.) amazonensis. Aluminum phthalocyanine chloride (AlPcCl), Aluminum phthalocyanine hydroxide (AlPcOH) and zinc phthalocyanine (PcZn) were tested in the presence (matte red LED, potency of 2.5-2.3 μW for 30 min) and absence of light against L. amazonensis promastigotes and the parasite viability was evaluated after 24, 48 and 72 h. The amastigote forms were treated with AlPcCl and AlPcOH, following the same lighting protocols described for the promastigote forms, being evaluated after 24 h. Cytotoxicity to human erythrocytes and peritoneal macrophages was also evaluated. The results showed that AlPcCl and AlPcOH in the presence of light have antileishmania activity, with leishmanistatic effects on promastigotes and amastigotes of L. amazonensis, without causing cytotoxicity to peritoneal macrophages and erythrocytes. The concentrations that inhibited 50% of the promastigote forms after 24 h of light exposure were 0.21 ± 0.08 μM for AlPcCl and 0.23 ± 0.06 μM for AlPcOH. In 48 h and 72 h after the treatment, the IC₅₀ of AlPcCl was 0.13 ± 0.02 and 0.12 ± 0.03 μM and for AlPcOH was 0.14 ± 0.01 μM and 0.11 ± 0.01 μM, respectively. PcZn showed no activity on promastigotes of L. amazonensis. This study showed a substantial photodynamic activity of the phthalocyanines AlPcCl and AlPcOH against intracellular amastigotes forms of L. amazonensis after irradiation, presenting IC₅₀ values of 0.62 ± 0.06 μM and 0.92 ± 0.12 μM, respectively. These results support the possibility of using photodynamic therapy for the treatment of cutaneous leishmaniasis.

Use of Protoporphyrin Fluorescence to Determine Clinical Target Volume for Non-melanotic Skin Cancers Treated with Primary Radiotherapy

PURPOSE 

Non-melanotic skin cancers remain the most commonly diagnosed cancers. Radiotherapy and surgery are the most common treatment options. Radiotherapy has a recurrence rate of up to 20% for basal or squamous cell cancers. One of the difficulties is to determine the extent of disease for poorly demarcated tumors. This study utilizes protoporphyrin (PpIX) fluorescence to provide information on the extent of subclinical disease for poorly demarcated tumors treated with radiotherapy.

MATERIALS AND METHODS 

For 33 patients, PpIX photo-delineation was used to determine the clinical target volume (CTV2), which was compared to current conventional margins used to account for microscopic disease.

RESULTS 

The use of PpIX photo-delineation demonstrated a significantly larger CTV of 15 mm compared to the conventional 10 mm (p = 0.03) for poorly demarcated lesions. A larger CTV was also demonstrated with PpIX photo-delineation for all basal cell carcinomas (13 mm, p = 0.03) as well as for non-nasal lesions (14 mm, p = 0.04). A trend towards an increased CTV was also noted for squamous cell carcinomas (16 mm, p = 0.19) and nasal primary sites (14 mm, p = 0.11). Nasal primary malignancies had multifocal PpIX uptake in 94% of cases. There was one case of local recurrence and one case of distant recurrence, with an average follow-up time of 22 months.

CONCLUSIONS 

The margins currently used to account for subclinical disease may underestimate the extent of microscopic spread for poorly demarcated tumors. Longer follow-up with larger pools of patients are necessary to determine if using PpIX photo-delineation translates into significantly improved clinical outcomes.

The potential of photodynamic therapy (PDT)-Experimental investigations and clinical use

Photodynamic therapy (PDT) is an intensively studied part of medicine based on free radicals. These reactive species, extremely harmful for whole human organism, are used for eradication numerous diseases. Specific structure of ill tissues causes accumulation free radicals inside them without attack remaining healthy tissues. A rapid development of medicine and scientific research has led to extension of PDT towards treatment many diseases such as cancer, herpes, acne and based on antimicrobials. The presented review article is focused on the aforementioned disorders with accurate analysis of the newest available scientific achievements. The discussed cases explicitly indicate on high efficacy of the therapy. In most cases, free radicals turned out to be solution of many afflictions. Photodynamic therapy can be considered as promising treatment with comparable effectiveness but without side effects characteristic for chemotherapy.

Synthesis of chemically diverse esters of 5-aminolevulinic acid for photodynamic therapy via the multicomponent Passerini reaction

A chemically diverse set of 5-aminolevulinic acid prodrugs were obtained via a Passerini reaction and studied as photodinamic agents in vitro.

Optimization of protoporphyrin IX skin delivery for topical photodynamic therapy: Nanodispersions of liquid-crystalline phase as nanocarriers

Nanodispersions of liquid-crystalline phases (NLPs) composed of monoolein and oleic acid were chosen as nanocarriers to improve the topical retention of the photosensitizer protoporphyrin IX (PpIX) and thereby optimize photodynamic therapy (PDT) using this photosensitizer. The nanodispersions were characterized by polarized light microscopy, small-angle X-ray diffraction and dynamic light scattering. The stability and encapsulation efficiency (EE%) of the nanodispersions were also evaluated. In vitro and in vivo skin penetration studies were performed to determine the potential of the nanodispersions for cutaneous application. In addition, skin penetration and skin irritancy (in an animal model) after in vivo application were visualized by fluorescence light microscopy. The nanodispersion obtained was characterized as a monodisperse system (~150.0 nm) of hexagonal liquid-crystalline phase, which provided a high encapsulation efficiency of PpIX (~88%) that remained stable over 90 days of investigation. Skin penetration studies demonstrated that the nanodispersion enhanced PpIX skin uptake 11.8- and 3.3-fold (in vitro) and 23.6- and 20.8-fold (in vivo) compared to the PpIX skin uptake of control formulations, respectively. In addition, the hexagonal phase nanodispersion did not cause skin irritation after application for two consecutive days. Overall, the results show that the nanocarrier developed is suitable for use in topical PDT with PpIX.

Topical Treatment Modalities for Old World Cutaneous Leishmaniasis: A Review

Diagnosis and therapy of cutaneous leishmaniasis (CL) can be difficult due to the variability of the clinical pictures and resistance to therapy. There is no vaccine currently available for CL. The aim of the present review is to describe different topical treatment modalities for old world CL. The mainstays of treatment for old world CL are pentavalent antimony compounds which are administered parenterally or intralesionally. New topical treatment alternatives have been available within the past few years. Amongst several treatments used topically, physical therapies including cryotherapy, heat therapy and CO2 laser are promising for the treatment of old world CL. Along with that, other randomized placebo controlled trials should be designed to find new effective therapeutic regimens.

Simultaneous delivery of cytotoxic and biologic therapeutics using nanophotoactivatable liposomes enhances treatment efficacy in a mouse model of pancreatic cancer

A lack of intracellular delivery systems has limited the use of biologics such as monoclonal antibodies (mAb) that abrogate molecular signaling pathways activated to promote escape from cancer treatment. We hypothesized that intracellular co-delivery of the photocytotoxic chromophore benzoporphyrin derivative monoacid A (BPD) and the anti-VEGF mAb bevacizumab in a nanophotoactivatable liposome (nanoPAL) might enhance the efficacy of photodynamic therapy (PDT) combined with suppression of VEGF-mediated signaling pathways. As a proof-of-concept we found that nanoPAL-PDT induced enhanced extra- and intracellular bevacizumab delivery and enhanced acute cytotoxicity in vitro. In an in vivo subcutaneous mouse model of pancreatic ductal adenocarcinoma, nanoPAL-PDT achieved significantly enhanced tumor reduction. We attribute this to the optimal incorporation of insoluble BPD into the lipid bilayer, enhancing photocytotoxicity, and the simultaneous spatiotemporal delivery of bevacizumab, ensuring efficient neutralization of the rapid but transient burst of VEGF following PDT. From the Clinical Editor: Most patients with pancreatic ductal adenocarcinoma (PDAC) by the time present the disease it is very advanced, which unavoidably translates to poor survival. For these patients, use of traditional chemotherapy often becomes ineffective due to tumor resistance to drugs. Photodynamic therapy (PDT) can be an effective modality against chemo-resistant cancers. In this article, the authors investigated the co-delivery of a photocytotoxic agent and anti-VEGF mAb using liposomes. This combination was shown to results in enhanced tumor killing. This method should be applicable to other combination of treatments.

Clinical efficacy of 5-aminolevulinic acid photodynamic therapy in the treatment of moderate to severe facial acne vulgaris

Acne vulgaris is considered as a therapeutic challenge in terms of managing ongoing symptoms and preventing scar formation. Although there are many available treatments for alleviating acne, therapies for resistant or moderate-to-severe forms have been limited to systemic agents that are accompanied by potentially severe side-effects. While, aminolevulinic acid (ALA) photodynamic therapy (PDT) has increasingly been used as a simple and safe therapeutic option of acne vulgaris, the clinical efficacy requires confirmation in further studies. The aim of this study was to investigate the efficacy and safety of 5-ALA-PDT in the treatment of moderate-to-severe facial acne vulgaris. A total of 50 patients with moderate-to-severe facial acne were enrolled in the study and randomly divided equally into a therapy group and a control group. In the therapy group, the patients were treated with 5% 5-ALA for 1.5 h, followed by three 20-min doses of infrared radiation once a week; in the control group, the patients were treated with three 20 min doses of infrared radiation without 5-ALA once a week. Both treatments lasted for 3 weeks. The clinical efficacy was determined by evaluating acne lesion counts at weeks 0, 2, 4 and 6. Total efficacy rate (TER) was the primary endpoint of the study, and was defined as the proportion of the patients whose treatment effectiveness evaluation was cured (≥90% of skin lesions improved) and excellent (60-89% improvement). Adverse effects were recorded throughout the study. The study was completed by 24 patients in the therapy group and 23 patients in the control group. The numbers of acne lesions significantly decreased. The TER of the therapy group was significantly higher than that of the control group at weeks 4 and 6. Adverse effects were observed in 12 patients of the therapy group and 2 patients of the control group. In the therapy group the most common adverse effect was a burning sensation (n=7), followed by transient hyperpigmentation (n=3) and acute acneform lesions (n=2), while in control group, the 2 patients experienced flushing and dryness. The adverse effects were all cured by a symptomatic approach prior to the end of the study. 5-ALA-PDT combined with infrared radiation is an effective and safe therapy for moderate-to-severe facial acne.

A new LED device used for photodynamic therapy in treatment of moderate to severe acne vulgaris

OBJECTIVE

This study investigated the efficacy and safety of a newly designed LED device used in photodiagnosis and photodynamic therapy of moderate to severe acne vulgaris in Chinese patients.

METHODS

Forty-six patients with moderate to severe facial acne showing high degrees of fluorescence by ultraviolet light examination were illuminated during ALA-PDT with two wavelengths of light (543-548 nm, and 630±6 nm, respectively) after 2 h of incubation with ALA. Each patient received treatment once every 30 days for two or three sessions. Two independent investigators assigned an acne severity score at baseline, one week after each treatment, as well as 4, 8, and 12 weeks after the completion of treatment. Adverse effects were recorded during and after each treatment. All patients rated their satisfaction with the results of treatment at a 12-week follow up visit.

RESULTS

The ALA-PDL treatment regimen showed an overall effectiveness rate of 89.13% (41/46 patients). Some degree of clinical efficacy was seen in 71.42%, 86.67%, and 95.83% of patients with grades IV, V, and VI acne, respectively, and the rate of clinical effectiveness increased with increasing acne severity. When compared with baseline scores, significant reductions in acne scores were obtained at 8, and 12 weeks after completion of treatment. Maximum efficacy was shown at the 12 week follow up. No severe adverse events were observed.

CONCLUSION

ALA-PDT administered with the newly designed LED device was an effective treatment for moderate to severe acne vulgaris, and side effects were mild and reversible.

Photodynamic therapy: one step ahead with self-assembled nanoparticles

Photodynamic therapy (PDT) is a promising treatment modality for cancer with possible advantages over current treatment alternatives. It involves combination of light and a photosensitizer (PS), which is activated by absorption of specific wavelength light and creates local tissue damage through generation of reactive oxygen species (ROS) that induce a cascade of cellular and molecular events. However, as of today, PDT is still in need of improvement and nanotechnology may play a role. PDT frequently employs PS with molecular structures that are highly hydrophobic, water insoluble and prone to aggregation. Aggregation of PS leads to reduced ROS generation and thus lowers the PDT activity. Some PS such as 5-aminolevulinic acid (ALA) cannot penetrate through the stratum corneum of the skin and systemic administration is not an option due to frequently encountered side effects. Therefore PS are often encapsulated or conjugated in/on nano-drug delivery vehicles to allow them to be better taken up by cells and to more selectively deliver them to tumors or other target tissues. Several nano-drug delivery vehicles including liposomes, fullerosomes and nanocells have been tested and reviewed. Here we cover non-liposomal self-assembled nanoparticles consisting of polymeric micelles including block co-polymers, polymeric micelles, dendrimers and porphysomes.

Protein microarray for complex apoptosis monitoring of dysplastic oral keratinocytes in experimental photodynamic therapy

Background

Photodynamic therapy is an alternative treatment of muco-cutaneous tumors that uses a light source able to photoactivate a chemical compound that acts as a photosensitizer. The phthalocyanines append to a wide chemical class that encompasses a large range of compounds; out of them aluminium-substituted disulphonated phthalocyanine possesses a good photosensitizing potential.

Results

The destructive effects of PDT with aluminium-substituted disulphonated phthalocyanine are achieved by induction of apoptosis in tumoral cells as assessed by flow cytometry analysis. Using protein microarray we evaluate the possible molecular pathways by which photodynamic therapy activates apoptosis in dysplastic oral keratinocytes cells, leading to the tumoral cells destruction. Among assessed analytes, Bcl-2, P70S6K kinase, Raf-1 and Bad proteins represent the apoptosis related biomolecules that showed expression variations with the greatest amplitude.

Conclusions

Up to date, the intimate molecular apoptotic mechanisms activated by photodynamic therapy with this type of phthalocyanine in dysplastic human oral keratinocytes are not completely elucidated. With protein microarray as high-throughput proteomic approach a better understanding of the manner in which photodynamic therapy leads to tumoral cell destruction can be obtained, by depicting apoptotic molecules that can be potentially triggered in future anti-tumoral therapies.

Prospective study of topical 5-aminolevulinic acid photodynamic therapy for the treatment of severe adolescent acne in Chinese patients

Acne vulgaris is one of the most common skin diseases in adolescents. In the present study, we aimed to evaluate the effectiveness and safety of topical 5-aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT) for the treatment of severe acne in Chinese adolescent patients. Twenty-one Chinese adolescent patients aged 12-18 years with Pillsbury III-IV severe facial acne were treated with three courses of ALA-PDT. A 5% ALA lotion was applied topically for 60 min followed by irradiation with light-emitting diode light at 633 nm with a light intensity of 75-80 mW/cm(2) and a light dose of 90-96 J/cm(2) . Clinical assessment was conducted before and after each treatment, and at each follow-up session. The total effective rates were 85.71%, 90.48%, and 95.23% after the three PDT sessions, and at the 4- and 8-week follow ups, respectively. ALA-PDT is an effective treatment for severe adolescent acne vulgaris, and is associated with mild and reversible side-effects.

Nanostructures of an amphiphilic zinc phthalocyanine polymer conjugate for photodynamic therapy of psoriasis

Psoriasis is a chronic inflammatory skin disease affecting 2-5% of the population worldwide and it severely affects patient quality of life. In this study, an amphiphilic zinc phthalocyanine polymer conjugate (ZPB) was synthesized, in which zinc phthalocyanine (ZnPc) was conjugated with the poly(ethylene glycol) (PEG) chain of Brij 58. ZPB showed two maximum UV-vis absorption wavelengths, 348 nm and 678 nm. A monomolecular micelle of ZPB formed in water with a mean size of 25 nm and zeta potential of -15 mV. The nanostructures aggregated into cloudy precipitates, which were easily dispersed. The nanostructure showed the shell-core structure with the ZnPc segments as the core and the PEG chains as the shell. The anti-psoriasis effect of the ZPB nanostructure was explored using a guinea pig psoriasis model. After comparing the anti-psoriasis effects of saline, light alone, ZPB alone, and the combination of light and ZPB, the combination of light and ZPB showed the best photodynamic therapy of psoriasis based on the light excitation of the photosensitizer ZPB and the psoriasis was nearly cured according to the histopathological investigation. The ZPB nanostructure is a promising anti-psoriasis nanomedicine based on photodynamic therapy.

A prospective study of pain control by a 2-step irradiance schedule during topical photodynamic therapy of nonmelanoma skin cancer

BACKGROUND

Topical photodynamic therapy (PDT) for selected nonmelanoma skin cancer using 5-aminolevulinic acid (ALA) or methyl aminolevulinate (MAL) has yielded high long-term complete response rates with very good cosmesis. Pain during light activation of the photosensitizer can be a serious adverse event. A 2-step irradiance protocol has previously been shown to minimize ALA-PDT pain.

OBJECTIVE

To determine the irradiance-dependent pain threshold for MAL-PDT, to adapt the 2-step protocol to a light-emitting diode (LED) light source, and assess clinical response.

METHODS

In this prospective study, 25 superficial basal cell carcinoma (sBCC) received an initial irradiance by laser at 40 or 50 mW/cm², or LED at 35 mW/cm² followed by an irradiance at 70 mW/cm² for a total of 75 J/cm². Pain levels were recorded for both irradiance steps. Efficacy was assessed at 6, 12, or 24 months.

RESULTS

Pain was mild in the 40/70 mW/cm² laser cohort. Three instances of irradiance-limiting pain occurred at 50/70 mW/cm². Pain was minimal in the 35/70 mW/cm² LED cohort. Clinical response rates were 80% in the 50/70 mW/cm² laser cohort and 90% in the 35/70 mW/cm² LED cohort.

CONCLUSION

Topical PDT can be effectively delivered to sBCC with minimal treatment-related pain by a 2-step irradiance protocol.

Pros, cons and future prospects of ALA-photodiagnosis, phototherapy and pharmacology in cancer therapy – A mini review

5-Aminolevulinic acid (ALA)-induced photodynamic therapy (ALA-PDT) has achieved remarkable research accomplishments over the past 30 years, yet its application in medical oncology still awaits clear recognition as a valid alternative therapeutic modality. It is well documented that topical ALA-PDT enables the treatment of multiple skin lesions simultaneously, and provides excellent cosmetic results with no acquired multi-drug resistance (MDR). Furthermore, upon disease recurrence the treatment can be repeated resulting in the same therapeutic efficacy. Additionally, in oncological surgery, ALA fluorescence-guided resection is a practical and simple method for visualizing intra-operative brain and urological tumors with millimeter accuracy. The urgent challenge is to direct future research of ALA-phototherapy and fluorescence diagnosis to the maturation of their medical status in oncology. Therefore, the future objectives are to amplify critical evidence-based results of ALA-PDT safety and efficacy and to validate its unique advantages over other technologies. Strong statistical PDT documentation and the positive predictive values of protoporphyrin IX (PpIX)-guided surgery will persuade the medical community to implement ALA-based therapeutics into standard clinical and surgical oncology practice. Research must address the phenomenon that no MDR develops as a consequence of PDT, since MDR is the major stumbling block in oncological therapeutics. A feasible goal should be to improve ALA administration protocols based on recent knowledge that preactivation of the enzyme porphobilinogen deaminase enhances PpIX accumulation in cancer cells and photodestruction. Moreover the recent introduction of multifunctional ALA prodrugs that maximize photosensitizer biosynthesis, targeting multiple sub-cellular targets, may increase PDT anti-cancer efficacy in additional disease settings. In conclusion, well-documented clinical results, new ALA delivery protocols, and novel multifunctional ALA prodrugs may advance ALA-PDT to becoming a front-line cancer therapy.

Photodynamic therapy: current status and future directions

Photodynamic therapy (PDT) is a minimally invasive therapeutic modality used for the management of a variety of cancers and benign diseases. The destruction of unwanted cells and tissues in PDT is achieved by the use of visible or near-infrared radiation to activate a light-absorbing compound (a photosensitizer, PS), which, in the presence of molecular oxygen, leads to the production of singlet oxygen and other reactive oxygen species. These cytotoxic species damage and kill target cells. The development of new PSs with properties optimized for PDT applications is crucial for the improvement of the therapeutic outcome. This review outlines the principles of PDT and discusses the relationship between the structure and physicochemical properties of a PS, its cellular uptake and subcellular localization, and its effect on PDT outcome and efficacy.

Light-regulated microRNAs

In addition to exposure to passive diurnal cycles of sunlight, humans are also subjected to intentional acute exposure to other types of electromagnetic radiation (EM). Understanding the molecular mechanisms involved in the physiological, pathological and therapeutic responses to exposure to radiation is an active area of research. With the advent of methods to readily catalog and identify patterns of changes in gene expression, many studies have reported changes in gene expression upon exposure of various human and mouse cells in vitro, whole experimental organisms such as mice and parts of human body. However, the molecular mechanisms underlying these broad ranging changes in gene expression are not yet fully understood. MicroRNAs, which are short, noncoding RNAs that regulate gene expression by targeting many messenger RNAs, are also emerging as important mediators of radiation-induced changes in gene expression and hence critical for the manifestation of light-induced cellular phenotypes and physiological responses. In this article, we review available knowledge on microRNAs implicated in responses to various forms of solar and other EM radiation. Based on this knowledge, we elaborate some unifying themes in the regulation and functions of some of these miRNAs.