Cutaneous sporotrichosis treated with methylene blue-daylight photodynamic therapy

Adjunctive methylene blue antimicrobial photodynamic therapy for mucocutaneous lesions of mycoses: three case reports

Dermatophytosis, paracoccidioidomycosis and sporotrichosis are mycoses caused by different fungal species with significant prevalence in Brazil and other countries. In some situations, they affect quality of life, especially in the most vulnerable populations. Antifungal drug therapy is the conventional treatment for these diseases, although some difficulties may occur. Adjunctive use of antimicrobial photodynamic therapy (aPDT) may reduce these challenges. Three patients were treated with aPDT and conventional antifungals. In all cases, the patients did not report pain, discomfort or side effects during or after the aPDT intervention. The adjunctive use of aPDT in the cases presented proved to be a safe, low-cost tool that may be promising for the treatment of different mycoses.

In vitro evaluation of the cis-[Ru(phen)2(pPDIp)]2+⁎⁎ complex for antimicrobial photodynamic therapy against Sporothrix brasiliensis and Candida albicans

BACKGROUND

Photodynamic therapy (PDT) activates a photosensitizer by visible light to generate cytotoxic oxygen species that lead to cell death. With proper illumination, PDT is often used in applications on superficial and sub-surface lesions. Sporotrichosis infection occurs by Sporothrix fungi which causes a skin wound, worsened by Candida albicans infections. This study investigated the photosensitizing efficiency of the Ru(phen)₂(pPDIp)(PF₆)₂ complex, RupPDIp, against S. brasiliensis and C. albicans.

MATERIAL AND METHODS

RupPDIp efficiency against these fungi was tested using 450 nm (blue light and 36 J/cm²) and 525 nm (green light, 25.2 J/cm²) at 0.05-20 μM concentrations. To ensure PDT effectiveness, control groups were tested in the absence and in the presence of RupPDIp under light irradiation and in the dark.

RESULTS

RupPDIp eliminated both fungi at ≤5.0 μM. Green light showed the best results, eliminating S. brasiliensis and C. albicans colonies at RupPDIp 0.5 μM and 0.05 μM, respectively.

CONCLUSION

RupPDIp is a promising photosensitizer in aPDT, eliminating 10⁶ CFU/mL of both fungi at 450 nm and 525 nm, with lower light doses and concentrations when treated with the green light compared to the blue light.

The zoonosis sporotrichosis can be successfully treated by photodynamic therapy: A scoping review

Sporotrichosis is a worldwide zoonosis, prevalent in tropical and subtropical regions. In recent years, there has been a substantial increase in human and feline cases reported in Brazil. Despite this, the antifungal treatment for sporotrichosis is still limited, and thus, research into new therapeutic modalities must be encouraged. Recently, photodynamic therapy has been introduced as a treatment for sporotrichosis. This work presents an overview of both in vitro and in vivo studies that have used photodynamic therapy in the context of photoinactivation of Sporothrix species. Until now, as far as the authors are aware, this is the first scope review specifically on photodynamic therapy for the treatment of sporotrichosis. A systematic electronic search was conducted in two databases: Web of Science and PubMed. Seven original articles published from 2010 to July 2021 were selected, six of which met the proposed inclusion and exclusion criteria and were considered in this scoping review. Concerning the photoinactivation of Sporothrix spp. the results have been promising as studies, in both animals and humans, have reported significant clinical and mycological effects. The most used photosensitizers were methylene blue and its derivatives, and aminolevulinic acid and its methyl derivative, methyl aminolevulinic acid. In conclusion, photodynamic therapy has great potential in treatment of sporotrichosis, as its fungicidal effect both in vitro and in vivo has clearly been demonstrated. Photodynamic therapy could be used in conjunction with classic antifungal agents to optimize treatment outcomes.

Towards effective cutaneous leishmaniasis treatment with light-based technologies. A systematic review and meta-analysis of preclinical studies

Cutaneous leishmaniasis (CL) is a neglected disease that represents a serious global public health concern. We performed a systematic review with meta-analysis targeting the use of light-based therapies on CL in preclinical studies since they are essential to identify the benefits, challenges, and limitations of proposing new technologies to fight CL. We searched Pubmed and Web of Science to include original preclinical researches in English that used light-based technologies to fight CL. Inclusion criteria encompassed any animal model for CL induction, an untreated infected group as the comparator, reliable and consistent methodology to develop and treat CL, focus on an antimicrobial therapeutic approach, and data for lesion size and/or parasite load in the infection site. We identified eight eligible articles, and all of them used photodynamic therapy (PDT). For the meta-analysis, three studies were included regarding the parasite load in the infection site and four comprised the lesion size. No overall statistically significant differences were observed between untreated control and PDT groups for parasite load. Differently, PDT significantly reduced the lesion size regardless of the protocol used to treat CL (in mm, SMD: -1.90; 95% CI: -3.74 to -0.07, p = 0.04). This finding is particularly encouraging since CL promotes disfiguring lesions that profoundly affect the quality of life of patients. We conclude that PDT is a new promising technology able to be topically used against CL if applied in more than one session, making it a promising ally for the management of CL.

5-Aminolevulinic acid-mediated photodynamic therapy has effective antifungal activity against Sporothrix globosa in vitro

BACKGROUND

An alternative therapy for sporotrichosis is necessary to reduce the treatment time and raise clinical efficacy. The 5-Aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) is a promising platform with which to treat mycoses. However, despite the worldwide prevalence of Sporothrix globosa, a causative agent of sporotrichosis, the effect of ALA-PDT on this pathogen has not been validated.

OBJECTIVES

The aim of this study was to evaluate the effect of ALA-PDT on S globosa and the protection of melanin through an in vitro study. The mechanisms involved were also investigated.

METHODS

To estimate the survival rate of S globosa treated with ALA-PDT and the protection offered by melanin, the conidia and yeast cells of wild-type S globosa (Mel+), other clinical strains, tricyclazole-treated Mel+ and an albino mutant strain (Mel-) were incubated with and without ALA or irradiation. Reactive oxygen species generation by Mel+ conidia induced by ALA-PDT was assayed. SEM and TEM were conducted to obverse ultrastructural changes in the conidia. A comet assay was performed to evaluate DNA damage.

RESULTS

The survival rate of S globosa conidia and yeast cells significantly decreased following incubation with 1.19M ALA and 162 J/cm² irradiation in vitro. Melanin was not only capable of protecting the conidia against ALA-PDT, but also against ALA or irradiation alone. After induction by ALA-PDT, alterations in reactive oxygen species generation, DNA damage and ultrastructural changes were observed.

CONCLUSIONS

ALA-PDT inhibits the survival of S globosa conidia in vitro and therefore has potential for the treatment of sporotrichosis.

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

BACKGROUND

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

SUMMARY

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

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

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

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.