Guidelines for topical photodynamic therapy: report of a workshop of the British Photodermatology Group

The Effect of Photodynamic Therapy on Enterococcus spp. and Its Application in Dentistry: A Scoping Review

Enterococci spp. are Gram-positive bacteria that cause mild to severe infections, many associated with the oral cavity, such as periapical infections and healthcare-associated infections (HAIs). Many of these infections become serious diseases that are difficult to resolve, specifically when multidrug-resistant (MDR) strains cause them. In recent years, the number of MDR strains of Enterococcus spp. has increased significantly. This increased prevalence of MDR strains produces significant pressure to generate more antimicrobial therapies, but there is a decline in the production of new antibiotics, driving the development of complementary therapies, such as photodynamic therapy (PDT). PDT combines a photosensitizer agent (PS), light, and oxygen to cause photooxidative stress in bacterial cells. PDT can eradicate Enterococcus spp. contaminations, improve the classic cleaning processes, and eradicate the bacteria in dental pieces. PDT's effectiveness can be improved with nanoparticles that function as carriers. Our work aims to describe the advances in PDT against Enterococcus spp. as a complement to antibiotic therapy, focusing on infections by Enterococcus faecium and Enterococcus faecalis, dental hygiene, and using nanoparticles to improve the antimicrobial effect. A systematic bibliographic search without a meta-analysis was conducted on various databases, using inclusion and exclusion criteria to identify the most relevant research. Of the 193 non-redundant articles found, 65 were selected for a systematic review, from which a summary table was created and a manual description was made. Photodynamic therapy for treating E. faecium and E. faecalis is a widely studied area, with promising results concerning bactericidal effectiveness and reductions in biofilm formation, particularly in regard to dental hygiene. Because most of the studies were conducted in vitro or ex vivo, the results indicated that there were not sufficient data to initiate clinical trials for safety and efficacy studies on humans.

Trends in photodynamic therapy for dermatology in recent 20 years: A scientometric review based on CiteSpace

OBJECTIVE

Analyze the research state and development trend of photodynamic therapy for dermatology using visual knowledge graphs derived from the Web of Science Core Collection database.

METHODS

The Web of Science Core Collection database was utilized as the search data source for the bibliometric analysis, and the associated articles published between January 1, 2000, and December 31, 2022, were obtained using the search terms "photodynamic therapy" and "dermatology". CiteSpace, VOSviewer, and additional tools were utilized for bibliometric analysis, and visual knowledge graphs were created.

RESULTS

Eight hundred and thirty two articles were retrieved in total, and 747 were included following de-duplication and transformation. The country with the greatest number of publications is the United States; the primary research institution was University of Copenhagen; and the references with the highest centrality were primarily concerned with the selection of photosensitizers; High frequency keywords primarily comprised 5 aminolevulinic acid and basal cell carcinoma; and the clustering graph revealed that all keywords fell into 11 categories.

CONCLUSION

In numerous areas of dermatology, photodynamic treatment is commonly employed. Current research focuses on nonneoplastic skin diseases and the choice of photosensitizers. Nonetheless, its specific mechanism and other applications merit further investigation.

Photodynamic therapy for the treatment of Pseudomonas aeruginosa infections: A scoping review

BACKGROUND

Pseudomonas aeruginosa is a Gram-negative bacillus that causes superficial and deep infections, which can be minor to life-threatening. Recently, P. aeruginosa has gained significant relevance due to the increased incidence of multidrug-resistant (MDR) strains that complicate antibiotic treatment. Due to MDR strains, alternative therapies, such as antimicrobial photodynamic therapy (PDT), are presented as a good option to treat nonsystemic infections. PDT combines a photosensitizer agent (PS), light, and oxygen to generate free radicals that destroy bacterial structures such as the envelope, matrix, and genetic material. This work aimed to identify the development stage of the PDT applied to P. aeruginosa to conclude which research stage should be emphasized more.

METHODS

Systematic bibliographic search in various public databases was performed. Related articles were identified using keywords, and relevant ones were selected using inclusion and exclusion criteria according to the PRISMA protocol.

RESULTS

We found 29 articles that meet the criteria, constituting a good body of evidence associated with using PDT against P. aeruginosa in vitro and less developed for in vivo research.

CONCLUSIONS

We conclude that PDT could become an effective adjunct to antimicrobial therapy against P. aeruginosa. This effectiveness depends on the PS used and the location of the infection. Many PS already demonstrated efficacy in PDT, but the evidence is supported significantly by in vitro and very few in vivo studies. Therefore, we conclude that further research efforts should focus on demonstrating the safety and efficacy of these PSs in vivo in animal infection models.

The evolution of clinical guidelines for antimicrobial photodynamic therapy of skin

Antimicrobial photodynamic therapy has become an important component in the treatment of human infection. This review considers historical guidelines, and the scientific literature to envisage what future clinical guidelines for treating skin infection might include. Antibiotic resistance, vertical and horizontal infection control strategies and a range of technologies effective in eradicating microbes without building up new resistance are described. The mechanism of action of these treatments and examples of their clinical use are also included. The research recommendations of NICE Guidelines on the dermatological manifestations of microbial infection were also reviewed to identify potential applications for PDT. The resistance of some microbes to antibiotics can be halted, or even reversed through the use of supplementary drugs, and so they are likely to persist as a treatment of infection. Conventional PDT will undoubtedly continue to be used for a range of skin conditions given existing healthcare infrastructure and a large evidence base. Daylight PDT may find broader antimicrobial applications than just Acne and Cutaneous Leishmaniasis, and Ambulatory PDT devices could become popular in regions where resources are limited or daylight exposure is not possible or inappropriate. Nanotheranostics were found to be highly relevant, and often include PDT, however, new treatments and novel applications and combinations of existing treatments will be subject to Clinical Trials.

Fluorescence and thermal imaging of non-melanoma skin cancers before and during photodynamic therapy

BACKGROUND

Photodynamic therapy (PDT) has been shown to be less effective on the extremities. Protoporphyrin-IX (PpIX) fluorescence and skin surface temperature are variables that have been implicated in the differences in efficacy with body site, but objective studies have not been undertaken.

OBJECTIVES

To further investigate observations from our previous study that temperature and fluorescence during pro-drug incubation are correlated, through a prospective objective investigation of the relationships between fluorescence and skin surface temperature before and during PDT and relationships with body site and efficacy.

METHODS

Eighteen patients with Bowen's disease or basal cell carcinoma, who had been referred for PDT, were recruited to this study. PpIX fluorescence and thermal measurements were recorded at intervals during the pro-drug incubation and irradiation phases of PDT. Pain immediately after irradiation, and outcome at 3- and 12-months were recorded.

RESULTS

Temperature and PpIX fluorescence were higher on the trunk than lower leg immediately before treatment (median temperature 32.7 °C vs. 27.8 °C, p < 0.05 and median fluorescence 16.5 vs. 6.7, p < 0.05). Higher pain levels were reported during PDT on the extremities (median 5.7 vs. 2.2, p < 0.05). Clearance rates at 12-months were 80 %.

CONCLUSIONS

The study supports a correlation between temperature and PpIX fluorescence during PDT, providing robust objective data to support our previous hypothesis and observations. The higher pain levels, lower PpIX fluorescence on the lower leg, and the high efficacy rates at all body sites irrespective of temperature and fluorescence indicates that relationships between PDT treatment conditions and parameters is likely to be multifactorial.

In vivo reflectance confocal microscopy for monitoring actinic keratosis treated with 5-aminolevulinic acid photodynamic therapy

BACKGROUND

Actinic keratosis (AK) occurs frequently in sun-exposed skin while its diagnosis and treatment were still in exploration.

MATERIALS AND METHODS

Thirty two patients with facial AK lesions were selected and examined with reflective confocal microscopy (RCM) firstly, followed by biopsy at the same site. RCM was used to observe AK lesions before 5-aminolevulinic acid photodynamic therapy (ALA-PDT) treatment, after the first treatment, after 4 treatments, and at 1 and 6 months follow-up. Retrospective analysis of RCM images was performed.

RESULTS

Thirty two AK cases showed initial RCM microscopic features including disorderly arranged epidermal cells (100%), atypical keratinocytes (100%), and blurry border between the epidermis and dermis (100%). 4 patients quitted trail. After treatments, 24 cases showed basically regular arrangement of epidermal cells, absent atypical keratinocytes, and clear border between epidermis and dermis, while 4 cases improved little. At 1 and 6 months follow-up, 23 cases remained relapse-free while 1 case developed recurrent symptoms. Effective rate of 4 ALA-PDT treatments for AK was 100%; recurrence and cure rates were 4.2% and 82.1%, respectively.

CONCLUSION

ALA-PDT is effective to treat AK, while RCM can be recommended for in vivo evaluating and monitoring the effect of ALA-PDT on AK.

Phototherapy Combined with Carbon Nanomaterials (1D and 2D) and their Applications in Cancer Therapy

Carbon-based materials have attracted research interest worldwide due to their physical and chemical properties and wide surface area, rendering them excellent carrier molecules. They are widely used in biological applications like antimicrobial activity, cancer diagnosis, bio-imaging, targeting, drug delivery, biosensors, tissue engineering, dental care, and skin care. Carbon-based nanomaterials like carbon nanotubes and graphene have drawn more attention in the field of phototherapy due to their unique properties such as thermal conductivity, large surface area, and electrical properties. Phototherapy is a promising next-generation therapeutic modality for many modern medical conditions that include cancer diagnosis, targeting, and treatment. Phototherapy involves the major administration of photosensitizers (PSs), which absorb light sources and emit reactive oxygen species under cellular environments. Several types of nontoxic PSs are functionalized on carbon-based nanomaterials and have numerous advantages in cancer therapy. In this review, we discuss the potential role and combined effect of phototherapy and carbon nanomaterials, the mechanism and functionalization of PSs on nanomaterials, and their promising advantages in cancer therapy.

Photodynamic Therapy for Photodamage, Actinic Keratosis, and Acne in the Cosmetic Practice

Photodynamic therapy is the combination of the initial application of a photosensitive chemical on the skin and then using typically a blue filter light of varying spectrums. This treatment protocol has been more useful and functional than other chemical peels and lasers for a variety of conditions. There has been efficacy in antiviral treatments, such as herpetic lesions; malignant cancers of the head and neck; and lung, bladder, and skin cancers. It has been tested for prostate cancers, cervical cancer, colorectal cancer, lung cancer, breast cancer, esophageal cancer, stomach cancer, pancreatic cancer, vaginal cancer, gliomas, and erythroplasia of Queyrat.

Successful treatment of Pityriasis Versicolor by photodynamic therapy mediated by methylene blue

BACKGROUND

Although systemic therapies are recommended for severe or recalcitrant cases of pityriasis versicolor (PV), they are not free of important side effects and drug interactions. Photodynamic therapy (PDT) utilizes the action of singlet oxygen and free radicals produced by a light-activated photosensitizer to kill viruses, bacteria, or fungi. In this study, the effect of a PDT mediated by methylene blue (MB) in PV was evaluated.

METHODS

Five women with PV disseminated on the back and diagnosed by fresh microscopic analysis were treated with a solution of MB (2%) applied to the PV lesions for 3 minutes. Next, a red LED lamp (λ = 630±5 nm, 37 J/cm² ), placed 100 mm from the skin for 10 minutes, was applied on the dyed PV lesions. Six sessions of MB/PDT were implemented with a 2-week interval in between. Wood's lamp examination was used to monitor fungal infection at each time point.

RESULTS

Complete cure was observed in the five women at the 4 weeks post-treatment follow-up. Fluoresce images from PV lesions by Wood's lamp allowed to evaluate whether the lesions were healed or not at each time point. No patient showed relapse at the 6-month follow-up. The patients did not have any adverse effect, and good cosmetic outcome was observed.

CONCLUSIONS

Six sessions of MB/PDT spaced at 14-day intervals are sufficient for the treatment for PV in healthy patients.

Comparative analysis of single- and dual-wavelength photodynamic therapy regimes with chlorin-based photosensitizers: animal study

Two pronounced absorption peaks in blue and red ranges of the chlorin-based photosensitizer (PS) absorption spectrum provide additional benefits in photodynamic therapy (PDT) performance. Differing optical properties of biological tissues in these ranges allow for both dual-wavelength diagnostics and PDT performance. We provide a comparative analysis of different PDT regimes performed with blue and red lights and their combination, with doses varying from 50 to 150  J  /  cm². The study was performed on the intact skin of a rabbit ear inner surface, with the use of chlorin e6 as a PS. PDT procedure protocol included monitoring of the treated site with fluorescence imaging technique to evaluate PS accumulation and photobleaching, as well as with optical coherence tomography (OCT) to register morphological and functional responses of the tissue. Optical diagnostic observations were compared with the results of histopathology examination. We demonstrated that PDT procedures with the considered regimes induce weaker organism reaction manifested by edema in normal tissue as compared to irradiation-only exposures with the same light doses. The light doses delivered with red light induce weaker tissue reaction as compared to the same doses delivered with blue light only or with a combination of red and blue lights in equal parts. Results of in-vivo OCT monitoring of tissue reaction are in agreement with the results of histopathology study.

Topical 5-aminolevulinic acid photodynamic therapy for intra anal-rectal warts

Background: Condylomata acuminata (CA) are a common sexually transmitted disease. The recurrence rate of condyloma acuminatum using traditional treatments is higher than that of applying photodynamic therapy, and a variety of adverse reactions after treatment. At the same time, different parts of condyloma acuminatum after treatment recurrence rate is also different, especially for intra anal-rectal warts.Objective: To evaluate whether using photodynamic therapy (PDT) can effectively reduce recurrence of condylomata acuminata for intra anal-rectal warts.Methods: After the confirmation of the diagnosis of intra anal-rectal warts, the patients were treated with PDT with 5-aminolevulinic acid hydrochloride (ALA). PDT was performed with irradiation of 18-36 J/cm² at an irradiance of 20-40 mW/cm² with light-emitting diode (LED) light energy, wavelength 635 nm. We used a special PDT light equipment for intra anal-rectal area warts. PDT was repeated once every week for 4 weeks.Results: After PDT, the complete clearance rate was 76.1% (35 of 46 patients). At the end of the 12 weeks followed, recurrence occurred in five cases. We recorded pain in all 46 patients and the average visual analog scale (VAS) pain score was 6.96 ± 1.41 points.Conclusion: The treatment with PDT is effective in reducing the high rate of recurrence for intra anal-rectal warts. Pain is still a great challenge for the therapy.

Hydrogels: soft matters in photomedicine

Photodynamic therapy (PDT), a shining beacon in the realm of photomedicine, is a non-invasive technique that utilizes dye-based photosensitizers (PSs) in conjunction with light and oxygen to produce reactive oxygen species to combat malignant tissues and infectious microorganisms. Yet, for PDT to become a common, routine therapy, it is still necessary to overcome limitations such as photosensitizer solubility, long-term side effects (e.g., photosensitivity) and to develop safe, biocompatible and target-specific formulations. Polymer based drug delivery platforms are an effective strategy for the delivery of PSs for PDT applications. Among them, hydrogels and 3D polymer scaffolds with the ability to swell in aqueous media have been deeply investigated. Particularly, hydrogel-based formulations present real potential to fulfill all requirements of an ideal PDT platform by overcoming the solubility issues, while improving the selectivity and targeting drawbacks of the PSs alone. In this perspective, we summarize the use of hydrogels as carrier systems of PSs to enhance the effectiveness of PDT against infections and cancer. Their potential in environmental and biomedical applications, such as tissue engineering photoremediation and photochemistry, is also discussed.

Impact of red versus blue light on tolerability and efficacy of PDT: a randomized controlled trial

Various light sources may be used for photodynamic therapy of actinic keratosis since photosensitizing agents are activated by different wavelengths. However, the relative impact of red and blue light irradiation on the efficacy and tolerability of therapy is controversial.

OBJECTIVE

The aim of this study is to compare the efficacy and tolerability of therapy with red versus blue light sources, as well as the patients' evaluation of cosmetic results, clinical response, painfulness and preferred light source for future photodynamic treatments.

METHODS

This is a prospective, single-center, randomized, controlled, open-label study with 28 patients undergoing elective photodynamic therapy.

RESULTS

Red and blue light sources both showed very good results with a complete response rate of 84 % and 85 % respectively. Pain during photodynamic therapy was 6.1 vs. 5.4 (and 2.1 vs. 1.5 eight hours after therapy) on the visual analogue scale. Although these differences were statistically significant, the clinical relevance is low, since the number of therapy interruptions were equally distributed in both groups, and patients' subjective evaluation of the treatment showed no personal preference towards the light sources.

CONCLUSION

Both light sources showed very good clinical results and satisfactory tolerability in this study.

Photodynamic therapy for treatment of usual-type vulvar intraepithelial neoplasia: a case report and literature review

Vulvar intraepithelial neoplasia (VIN) is a pre-malignant condition of the vulvar skin that is found in 50% to 70% of patients with vulvar squamous cell cancer and is regarded as a precursor of vulvar tumors. Thus far, treatment remains lesion- and patient-specific. Here, we describe a VIN patient who presented with a 15-month history of large lesions in the bilateral labium, associated with human papillomavirus infection. The lesions were inappropriate for surgical excision and laser ablation because of their size; therefore, they were treated with photodynamic therapy and concurrent topical 5-aminolevulinic acid hydrochloride. The patient showed no recurrence throughout 2 years of post-treatment follow-up, and reported only slight pain during treatment. Moreover, no significant side effects or scarring were detected. Thus, we conclude that photodynamic therapy can be a useful alternative treatment for large VIN in the bilateral labium that cannot be excised or ablated.

Efficacy and safety of photodynamic therapy with amino-5-laevulinate nanoemulsion versus methyl-5-aminolaevulinate for actinic keratosis: A meta-analysis

BACKGROUND

Photodynamic therapy is an effective treatment for actinic keratosis. 5-aminolevulinic acid nanoemulsion (BF-200 ALA) and methyl-5-aminolevulinate (MAL) are both prodrugs for the treatment of actinic keratosis with photodynamic therapy. A comparison of the efficacy and safety between the drugs is critical for clinical practice.

OBJECTIVES

To investigate if photodynamic therapy in combination with BF-200 ALA is superior to photodynamic therapy with MAL for actinic keratosis.

METHODS

We performed a meta-analysis to investigate the combination of photodynamic therapy with BF-200 ALA and with MAL. The PubMed, Cochrane Library, Web of Science and EMBASE databases were searched to select eligible randomized controlled trials. Our search was conducted on April 1, 2019, and included the search terms "5-aminolevulinic acid nanoemulsion or BF-200 ALA", "methyl-5-aminolevulinate or methyl aminolaevulinate" and "actnic keratosis". Cochrane Risk of Bias Tool was used to estimate the risk of bias.

RESULTS

The meta-analysis consisted of 5988 actinic keratosis lesions in five eligible randomized controlled trials, with a total of 2953 actinic keratosis lesions treated with BF-200 ALA and 3035 actinic keratosis lesions treated with MAL. BF-200 ALA in combination with photodynamic therapy showed significantly higher overall complete clearance rates (RR: 1.07, 95% CI 1.02-1.12, p = 0.01) and 3 month complete clearance rates (RR: 1.09, 95% CI 1.06-1.12, p < 0.00001) compared to MAL. A subgroup analysis was performed for photodynamic therapy combined with BF-200 ALA, revealing increased complete clearance rates of grade II-III lesions in comparison with MAL (RR: 1.24, 95% CI 1.05-1.46, p = 0.01). Compared with MAL, the pooled relative risk for the meta-analysis for recurrence was 0.67 (95% CI 0.48-0.92, p = 0.01) at 12 month after BF-200 ALA treatment.

CONCLUSION

Photodynamic therapy with BF-200 ALA has a 9% better chance of complete clearance at 3 months and a 24% better chance of grade II-III lesions after treatment than with MAL for patients with actinic keratosis.

Photodynamic therapy for cancer: Role of natural products

Photodynamic therapy (PDT) is a promising modality for the treatment of cancer. PDT involves administering a photosensitizing dye, i.e. photosensitizer, that selectively accumulates in tumors, and shining a light source on the lesion with a wavelength matching the absorption spectrum of the photosensitizer, that exerts a cytotoxic effect after excitation. The reactive oxygen species produced during PDT are responsible for the oxidation of biomolecules, which in turn cause cell death and the necrosis of malignant tissue. PDT is a multi-factorial process that generally involves apoptotic death of the tumor cells, degeneration of the tumor vasculature, stimulation of anti-tumor immune response, and induction of inflammatory reactions in the illuminated lesion. Numerous compounds with photosensitizing activity have been introduced commercially. Although many papers have been published with regard to PDT in the last decade, there has been relatively little focus on natural medicinal plant extracts and compounds derived therefrom. Herbal plants and their extracts are natural substances, and in comparison with synthetic chemicals are considered "green". This review focuses on the different mechanisms of PDT and discusses the role of various plant extracts and natural compounds either alone or in combination for carrying out PDT on different types of cancers.

Nanoscale Metal-Organic Frameworks for Phototherapy of Cancer

Phototherapy involves the irradiation of tissues with light, and is commonly implemented in the forms of photodynamic therapy (PDT) and photothermal therapy (PTT). Photosensitizers (PSs) are often needed to improve the efficacy and selectivity of phototherapy via enhanced singlet oxygen generation in PDT and photothermal responses in PTT. In both cases, efficient and selective delivery of PSs to the diseased tissues is of paramount importance. Nanoscale metal-organic frameworks (nMOFs), a new class of hybrid materials built from metal connecting points and bridging ligands, have been examined as nanocarriers for drug delivery due to their compositional and structural tunability, highly porous structures, and good biocompatibility. This review summarizes recent advances on using nMOFs as nanoparticle PSs for applications in PDT and PTT.

Indocyanine-Green Fluorescence-GUIDED Liver Resection of Metastasis from Squamous Cell Carcinoma Invading the Biliary Tree

Background. The concept of fluorescence-guided navigation surgery based on indocyanine green (ICG) is a developing interest in many fields of surgical oncology. The technique seems to be promising also during hepatic resection. Case Presentation. We reported our experience of ICG-fluorescence-guided liver resection of metastasis located at VIII Couinaud's segment from colon squamous cell carcinoma of a 74-year-old male patient. Results. After laparotomy, the fluorescing tumour has been clearly identified on the liver surface. We have also identified that a large area of fluorescent parenchyma that gets from the peripheral of the lesion up to the portal pedicle such as the neoplasia would interest the right biliary tree in the form of neoplastic lymphangitis. This datum was not preoperatively known. Conclusion. Fluorescent imaging navigation liver resection could be a feasible and safe technique helpful in identifying additional characteristics of lesion. It could be a powerful tool but further studies are required.

Antimicrobial effects of photodynamic therapy

The microorganisms that cause infections are increasing their resistance to antibiotics. In this context, alternative treatments are necessary. The antimicrobial photodynamic therapy (aPDT) is a therapeutic modality based on photosensitizing molecules that end up generating reactive oxygen species that induce the destruction of the target cells when are irradiated with light of a suitable wavelength and at a proper dose. The cells targeted by aPDT are all types of microorganisms (bacteria, fungi and parasites) including viruses and has been proven effective against representative members of all of them. In the field of dermatology, aPDT has been tested with promising results in different infections such as chronic ulcers, acne, onychomycosis and other cutaneous mycoses, as well as in leishmaniasis. Therefore, it is presented as a possible treatment option against the agents that cause skin and/or mucous infections.

Killing malignant melanoma cells with protoporphyrin IX-loaded polymersome-mediated photodynamic therapy and cold atmospheric plasma

Traditional cancer treatments contain several limitations such as incomplete ablation and multidrug resistance. It is known that photodynamic therapy (PDT) is an effective treatment for several tumor types especially melanoma cells. During the PDT process, protoporphyrin IX (PpIX), an effective photosensitizer, can selectively kill cancer cells by activating a special light source. When tumor cells encapsulate a photosensitizer, they can be easily excited into an excited state by a light source. In this study, cold atmospheric plasma (CAP) was used as a novel light source. Results of some studies have showed that cancer cells can be effectively killed by using either a light source or an individual treatment due to the generation of reactive oxygen species and electrons from a wide range of wavelengths, which suggest that CAP can act as a potential light source for anticancer applications compared with UV light sources. Results of the present in vitro study indicated for the first time that PpIX can be successfully loaded into polymersomes. Most importantly, cell viability studies revealed that PpIX-loaded polymersomes had a low toxicity to healthy fibroblasts (20% were killed) at a concentration of 400 µg/mL, but they showed a great potential to selectively kill melanoma cells (almost 50% were killed). With the application of CAP posttreatment, melanoma cell viability significantly decreased (80% were killed) compared to not using a light source (45% were killed) or using a UV light source (65% were killed). In summary, these results indicated for the first time that PpIX-loaded polymersomes together with CAP posttreatment could be a promising tool for skin cancer drug delivery with selective toxicity toward melanoma cells sparing healthy fibroblasts.

Photodynamic therapy mediated by acai oil (Euterpe oleracea Martius) in nanoemulsion: A potential treatment for melanoma

Melanoma is the most aggressive and lethal form of skin cancer, responsible for >80% of deaths. Standard treatments for late-stage melanoma usually present poor results, leading to life-threatening side effects and low overall survival. Thus, it is necessary to rethink treatment strategies and design new tools for the treatment of this disease. On that ground, we hereby report the use of acai oil in nanoemulsion (NanoA) as a novel photosensitizer for photodynamic therapy (PDT) used to treat melanoma in in vitro and in vivo experimental models. NIH/3T3 normal cells and B16F10 melanoma cell lines were treated with PDT and presented 85% cell death for melanoma cells, while maintaining high viability in normal cells. Flow cytometry indicated that cell death occurred by late apoptosis/necrosis. Tumor bearing C57BL/6 mice treated five times with PDT using acai oil in nanoemulsion showed tumor volume reduction of 82% in comparison to control/tumor group. Necrotic tissue per tumor area reached its highest value in PDT-treated mice, supporting PDT efficacy. Overall, acai oil in nanoemulsion was an effective photosensitizer, representing a promising source of new photosensitizing molecules for PDT treatment of melanoma, a tumor with an inherent tendency to be refractory for this type of therapy.

Unilateral Basal Cell Carcinomas: An Unusual Entity Treated with Photodynamic Therapy

Background:

Unilateral localized basal cell carcinomas are an uncommon finding that presents both a diagnostic and therapeutic challenge. Exclusion of unilateral nevoid basal cell carcinoma syndrome is indicated. There are few reports in the literature regarding this entity and even less regarding therapeutic strategies.

Objective:

We present a patient with unilateral localized basal cell carcinomas who was successfully treated with photodynamic therapy.

Methods:

Photodynamic therapy was started using Levulan® Kerastick® as previously described. The topical solution was applied to the patient's back and illuminated the following day via the BLU-U Blue Light Illuminator.

Results:

The patient tolerated the procedure well and without complications. The patient had an excellent therapeutic response with no clinically apparent basal cell carcinomas for 18 months.

Conclusions:

We report a patient with unilateral basal cell carcinomas successfully treated with photodynamic therapy. This uncommon entity represents a diagnostic challenge in its inherent absence of the classic clinical and radiographic findings of nevoid basal cell carcinoma syndrome. Like nevoid basal cell carcinoma syndrome, unilateral basal cell carcinomas poses a therapeutic challenge with the sheer number of cutaneous tumors. The use of photodynamic therapy carries a proven therapeutic efficacy, a low rate of adverse events and excellent cosmesis.

Intermolecular Structural Change for Thermoswitchable Polymeric Photosensitizer

We developed a thermoswitchable polymeric photosensitizer (T-PPS) by conjugating PS (Pheophorbide-a, PPb-a) to a temperature-responsive polymer backbone of biocompatible hydroxypropyl cellulose. Self-quenched PS molecules linked in close proximity by π-π stacking in T-PPS were easily transited to an active monomeric state by the temperature-induced phase transition of polymer backbones. The temperature-responsive intermolecular interaction changes of PS molecules in T-PPS were demonstrated in synchrotron small-angle X-ray scattering and UV-vis spectrophotometer analysis. The T-PPS allowed switchable activation and synergistically enhanced cancer cell killing effect at the hyperthermia temperature (45 °C). Our developed T-PPS has the considerable potential not only as a new class of photomedicine in clinics but also as a biosensor based on temperature responsiveness.

The hydroxypyridinone iron chelator CP94 increases methyl-aminolevulinate-based photodynamic cell killing by increasing the generation of reactive oxygen species

Methyl-aminolevulinate-based photodynamic therapy (MAL-PDT) is utilised clinically for the treatment of non-melanoma skin cancers and pre-cancers and the hydroxypyridinone iron chelator, CP94, has successfully been demonstrated to increase MAL-PDT efficacy in an initial clinical pilot study. However, the biochemical and photochemical processes leading to CP94-enhanced photodynamic cell death, beyond the well-documented increases in accumulation of the photosensitiser protoporphyrin IX (PpIX), have not yet been fully elucidated. This investigation demonstrated that MAL-based photodynamic cell killing of cultured human squamous carcinoma cells (A431) occurred in a predominantly necrotic manner following the generation of singlet oxygen and ROS. Augmenting MAL-based photodynamic cell killing with CP94 co-treatment resulted in increased PpIX accumulation, MitoSOX-detectable ROS generation (probably of mitochondrial origin) and necrotic cell death, but did not affect singlet oxygen generation. We also report (to our knowledge, for the first time) the detection of intracellular PpIX-generated singlet oxygen in whole cells via electron paramagnetic resonance spectroscopy in conjunction with a spin trap.

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Augmentation of MAL-based photodynamic cell killing with CP94 increases necrosis.

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CP94 augmentation increases generation of ROS, likely to be mitochondria-localised.

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PpIX-generated ¹O₂ was detected in whole cells by EPR spectroscopy.

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Photodynamic cell killing was dependent primarily on ¹O₂.

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Superoxide/other ROS also contributed to the efficacy of photodynamic cell killing.

A Review of the Principles and Use of Lasers in Lower Limb Problems

Lasers present a unique light source with many clinical uses including a number of applications relevant to the lower extremity. In this article, the basic principles of lasers and their interactions with tissue will be reviewed. The article examines laser applications in skin and vascular disease including wound healing. The principles of laser safety are discussed, and relevant future developments are considered.

Drug Carrier for Photodynamic Cancer Therapy

Photodynamic therapy (PDT) is a non-invasive combinatorial therapeutic modality using light, photosensitizer (PS), and oxygen used for the treatment of cancer and other diseases. When PSs in cells are exposed to specific wavelengths of light, they are transformed from the singlet ground state (S₀) to an excited singlet state (S₁-Sn), followed by intersystem crossing to an excited triplet state (T₁). The energy transferred from T₁ to biological substrates and molecular oxygen, via type I and II reactions, generates reactive oxygen species, (¹O₂, H₂O₂, O₂*, HO*), which causes cellular damage that leads to tumor cell death through necrosis or apoptosis. The solubility, selectivity, and targeting of photosensitizers are important factors that must be considered in PDT. Nano-formulating PSs with organic and inorganic nanoparticles poses as potential strategy to satisfy the requirements of an ideal PDT system. In this review, we summarize several organic and inorganic PS carriers that have been studied to enhance the efficacy of photodynamic therapy against cancer.

Clinical use of photodynamic therapy in ocular tumors

Although the introduction of intravitreal anti-vascular endothelial growth factor drugs reduced the indications for photodynamic therapy in ophthalmology, it may still be used in various ocular tumors. Although many studies have shown that photodynamic therapy is effective in ocular tumors, the literature consists of case reports and series. In this review, we systematically performed a meta-analysis for the use of photodynamic therapy in circumscribed choroidal hemangioma, diffuse choroidal hemangioma, retinal capillary hemangioma, von Hippel-Lindau angiomatosis, choroidal melanoma, retinal astrocytoma, retinoblastoma, eyelid tumors, conjunctival tumors, and choroidal metastasis.

Photodynamic therapy in treatment of oral lichen planus

Oral lichen planus (OLP) is a relatively common chronic immunologic mucocutaneous disorder. Although there are many presenting treatments, some of them proved its failure. Recently, the use of photodynamic therapy (PDT) has been expanding due to its numerous advantages, as it is safe, convenient, and non-invasive and has toxic effect towards selective tissues. This article provides comprehensive review on OLP, its etiology, clinical features and recent non-pharmacological treatments. We also describe the topical PDT and its mechanisms. Our purpose was to evaluate the efficacy of PDT in treatment of OLP through collecting the data of the related clinical studies. We searched in PubMed website for the clinical studies that were reported from 2000 to 2014 using specific keywords: "photodynamic therapy" and "treatment of oral lichen planus". Inclusion criteria were English publications only were concerned. In the selected studies of photodynamic treatment, adult patients (more than 20 years) were conducted and the OLP lesions were clinically and histologically confirmed. Exclusion criteria were classical and pharmacological treatments of OLP were excluded and also the using of PDT on skin lesions of lichen planus. We established five clinical studies in this review where all of them reported improvement and effectiveness of PDT in treatment of OLP lesions. The main outcome of comparing the related clinical studies is that the photodynamic is considered as a safe, effective and promising treatment modality for OLP.

Photodynamic therapy with methyl aminolevulinate in the treatment of basal cell carcinoma

The article presents the results of the studies on the effectiveness of treatment basal cell carcinoma of the skin with photodynamic therapy with 5-aminolevulinic acid and methyl aminolevulinate. The results of the comparing trials between photodynamic therapy with methyl aminolevulinate and different other treatment modalities are presented.

Potential of microneedles in enhancing delivery of photosensitising agents for photodynamic therapy

Photodynamic therapy can be used in the treatment of pre-malignant and malignant diseases. It offers advantages over other therapies currently used in the treatment of skin lesions including avoidance of damage to surrounding tissue and minimal or no scarring. Unfortunately, systemic delivery of photosensitising agents can result in adverse effects, such as prolonged cutaneous photosensitivity; while topical administration lacks efficacy in the clearance of deeper skin lesions and those with a thick overlying keratotic layer. Therefore, enhancement of conventional photosensitiser delivery is desired. However, the physicochemical properties of photosensitising agents, such as extreme hydrophilicity or lipophilicity and large molecular weights make this challenging. This paper reviews the potential of microneedles as a viable method to overcome these delivery-limiting physicochemical characteristics and discusses the current benefits and limitations of solid, dissolving and hydrogel-forming microneedles. Clinical studies in which microneedles have successfully improved photodynamic therapy are also discussed, along with benefits which microneedles offer, such as precise photosensitiser localisation, painless application and reduction in waiting times between photosensitiser administration and irradiation highlighted.

Photodynamic therapy: oncologic horizons

Photodynamic therapy (PDT) is a light-based intervention with a long and successful clinical track record for both oncology and non-malignancies. In cancer patients, a photosensitizing agent is intravenously, orally or topically applied and allowed time to preferentially accumulate in the tumor region. Light of the appropriate wavelength and intensity to activate the particular photosensitizer employed is then introduced to the tumor bed. The light energy will activate the photosensitizer, which in the presence of oxygen should allow for creation of the toxic photodynamic reaction generating reactive oxygen species. The photodynamic reaction creates a cascading series of events including initiation of apoptotic and necrotic pathways both in tumor and neovasculature, leading to permanent lesion destruction often with upregulation of the immune system. Cutaneous phototoxicity from unintentional sunlight exposure remains the most common morbidity from PDT. This paper will highlight current research and outcomes from the basic science and clinical applications of oncologic PDT and interpret how these findings may lead to enhanced and refined future PDT.

Photodynamic therapy in dermatology: Dundee clinical and research experience

Topical photodynamic therapy (PDT) is increasingly accepted and used as a highly effective treatment for superficial non-melanoma skin cancer and dysplasia. We describe the developments in topical PDT for the treatment of skin diseases in our own PDT Centre in Dundee, both clinically and from a research base. Improvements in PDT could be achieved by optimisation of photosensitiser and light delivery, and these goals underpin the aims of our centre. We hope to facilitate the dissemination of use of PDT in dermatology throughout Scotland and outline some of the progress in these areas.

Effect of methylene blue-mediated photodynamic therapy for treatment of basal cell carcinoma

Photodynamic therapy (PDT) is regarded as a treatment option for basal cell carcinoma (BCC). The aim of this study is to investigate the efficacy of methylene blue (MB)-based PDT in patients suffering from nodular or ulcerative BCCs. This study is a prospective clinical trial with a 6-months follow-up. The study setting is at the Dermatology Clinic at NILES, Cairo University, Egypt. Seventeen patients complaining of nodular BCC (nBCC) and three patients complaining of ulcerative BCC (uBCC) were taken as samples. Methylene blue, the photosensitizer, was prepared in two different formulas: liposomal-loaded MB (LMB) was prepared and formulated in hydrogel (MB 0.2%) to be used topically alone for treating BCCs <2 cm in diameter or to be combined with intralesional injection (ILI) of free MB 2% aqueous solution for treating BCCs ≥2 cm in diameter. A session was performed every 2 weeks until complete response (CR) of the lesion or for a maximum of six sessions. Clinical assessments of clinical improvement, dermatological photography, monthly follow-up visits for 6 months, and skin biopsy after 3 months of follow-up to confirm the response, recurrence, or both in cases in which the clinical evaluation was ambiguous. Seventeen patients of the 20 completed the study, 11 patients achieved CR with very good cosmetic outcome, photosensitizer tolerance, and minimal reported side effects. MB is a cheap promising alternative photosensitizer for PDT of nBCC.

Topical photodynamic therapy following excisional wounding of human skin increases production of transforming growth factor-β3 and matrix metalloproteinases 1 and 9, with associated improvement in dermal matrix organization

BACKGROUND

Animal studies report photodynamic therapy (PDT) to improve healing of excisional wounds; the mechanism is uncertain and equivalent human studies are lacking.

OBJECTIVES

To explore the impact of methyl aminolaevulinate (MAL)-PDT on clinical and microscopic parameters of human cutaneous excisional wound healing, examining potential modulation through production of transforming growth factor (TGF)-β isoforms.

METHODS

In 27 healthy older men (60-77 years), a 4-mm punch biopsy wound was created in skin of the upper inner arm and treated with MAL-PDT three times over 5 days. An identical control wound to the contralateral arm was untreated and both wounds left to heal by secondary intention. Wounds were re-excised during the inflammatory phase (7 days, n = 10), matrix remodelling (3 weeks, n = 8) and cosmetic outcome/dermal structure (9 months, n = 9). Production of TGF-β1, TGF-β3 and matrix metalloproteinases (MMPs) was assessed by immunohistochemistry alongside microscopic measurement of wound size/area and clinical assessment of wound appearance.

RESULTS

MAL-PDT delayed re-epithelialization at 7 days, associated with increased inflammation. However, 3 weeks postwounding, treated wounds were smaller with higher production of MMP-1 (P = 0·01), MMP-9 (P = 0·04) and TGF-β3 (P = 0·03). TGF-β1 was lower than control at 7 days and higher at 3 weeks (both P = 0·03). At 9 months, MAL-PDT-treated wounds showed greater, more ordered deposition of collagen I, collagen III and elastin (all P < 0·05).

CONCLUSIONS

MAL-PDT increases MMP-1, MMP-9 and TGF-β3 production during matrix remodelling, ultimately producing scars with improved dermal matrix architecture.