Phototoxic action of light emitting diode in the in vitro viability of Trichophyton rubrum

Treatment of Superficial Mycoses Using Photodynamic Therapy: A Systematic Review and Meta-Analysis

Objective: The purpose of this study is to evaluate the effectiveness and safety of photodynamic therapy (PDT) in treating superficial fungal infections, and provide reference for clinical application. Methods: In accordance with Population, Intervention, Comparator, and Outcome (PICO), the research question and keywords were formulated. Records published in English by PubMed, Embase, Cochrane Library, and Web of Science as of November 14, 2022 were retrieved, including the keywords "mycoses," "tinea," "photochemotherapy," etc. Besides, meta-analysis performed by STATA and PROSPERO registration code was CRD42022363448. Results: One thousand four hundred eighty-four records were identified and 18 articles involving 343 patients with superficial fungal infections were enrolled. The overall mycological cure rate of PDT is 55% [95% confidence interval (CI): 0.46-0.65]. The fungal cure rate using methylene blue (MB) as photosensitizer (PS) is 67% (95% CI: 0.55-0.79); using 5-aminolevulinic acid is 34% (95% CI: 0.21-0.47); and using methyl aminolevulinate is 56% (95% CI: 0.33-0.78). The fungal cure rate of moderate-to-severe onychomycosis according to Onychomycosis Severity Index is 60% (95% CI: 0.47-0.73) and that of moderate onychomycosis is 66% (95% CI: 0.56-0.76). It was observed that the treatment parameters did not follow the same standard across studies. The majority of the included studies were moderate to low biased. Conclusions: PDT, particularly using MB as PS, has a certain mycological cure rate and safety at treating superficial mycoses. Due to the insufficient number of studies on PDT in the treatment of superficial fungal infections and the small sample size of some studies, more studies with standardized PDT parameters, large sample size, and long follow-up periods are needed to prove that PDT has the potential to become an alternative to traditional antifungal therapy or to find a better combination between them.

Photosensitizers Mediated Photodynamic Inactivation against Fungi

Superficial and systemic fungal infections are essential problems for the modern health care system. One of the challenges is the growing resistance of fungi to classic antifungals and the constantly increasing cost of therapy. These factors force the scientific world to intensify the search for alternative and more effective methods of treatment. This paper presents an overview of new fungal inactivation methods using Photodynamic Antimicrobial Chemotherapy (PACT). The results of research on compounds from the groups of phenothiazines, xanthanes, porphyrins, chlorins, porphyrazines, and phthalocyanines are presented. An intensive search for a photosensitizer with excellent properties is currently underway. The formulation based on the existing ones is also developed by combining them with nanoparticles and common antifungal therapy. Numerous studies indicate that fungi do not form any specific defense mechanism against PACT, which deems it a promising therapeutic alternative.

Auto-focusing and quantitative phase imaging using deep learning for the incoherent illumination microscopy system

It is well known that the quantitative phase information which is vital in the biomedical study is hard to be directly obtained with bright-field microscopy under incoherent illumination. In addition, it is impossible to maintain the living sample in focus over long-term observation. Therefore, both the autofocusing and quantitative phase imaging techniques have to be solved in microscopy simultaneously. Here, we propose a lightweight deep learning-based framework, which is constructed by residual structure and is constrained by a novel loss function model, to realize both autofocusing and quantitative phase imaging. It outputs the corresponding in-focus amplitude and phase information at high speed (10fps) from a single-shot out-of-focus bright-field image. The training data were captured with a designed system under a hybrid incoherent and coherent illumination system. The experimental results verify that the focused and quantitative phase images of non-biological samples and biological samples can be reconstructed by using the framework. It provides a versatile quantitative technique for continuous monitoring of living cells in long-term and label-free imaging by using a traditional incoherent illumination microscopy system.

Methylene blue-mediated photodynamic therapy may be superior to 5% amorolfine nail lacquer for non-dermatophyte onychomycosis

BACKGROUND

Methylene blue-mediated photodynamic therapy as an antimicrobial has been reported to improve onychomycosis.

OBJECTIVES

To compare the short-term efficacy of methylene blue-mediated photodynamic therapy (MB-PDT) and 5% amorolfine nail lacquer (AMO) for toenail onychomycosis using higher intensity and shorter total treatment period than previously reported.

METHODS

Twenty-seven toenails with onychomycosis were randomized to receive either six biweekly sessions of MB-PDT or AMO for twelve weeks. Dermoscopic photography was used for onychomycosis severity index assessment under a dermoscopic inspection (d-OSI) at baseline, weeks 6, 10, 14 and 22 as well as microscopic and microbiological tests. Adverse events were recorded.

RESULTS

All subjects completed the study. Causative organisms found were exclusively non-dermatophytes including Fusarium spp., Asperillus spp.,and yeasts. Fifteen toenails received MB-PDT, whilst 12 received AMO. D-OSI showed greater improvement in MB-PDT than in AMO groups at weeks 6, 10, 14 as well as 22, with median changes of -2, -3, -4 (P = .055). and - 3 respectively in the MB-PDT group. The AMO group displayed the median d-OSI change of 0 throughout the study period. Mycological cure rate at 22 weeks in MB-PDT and AMO group was 73.3% and 66.67% (P > .05). Clinical cure rate at 22 weeks in MB-PDT (26.7%) was higher than AMO (16.7%), (P > .05). All patients only felt comfortably warm during the MB-PDT treatment. No major adverse events were found in both groups.

CONCLUSIONS

MB-PDT appeared to be more efficacious for non-dermatophyte onychomycosis than AMO particularly in a limited period and moderately severe onychomycosis.

Thermoresponsive Hydrogel-Loading Aluminum Chloride Phthalocyanine as a Drug Release Platform for Topical Administration in Photodynamic Therapy

Phthalocyanine aluminum chloride (Pc) is a clinically viable photosensitizer (PS) to treat skin lesions worsened by microbial infections. However, this molecule presents a high self-aggregation tendency in the biological fluid, which is an in vivo direct administration obstacle. This study proposed the use of bioadhesive and thermoresponsive hydrogels comprising triblock-type Pluronic F127 and Carbopol 934P (FCarb) as drug delivery platforms of Pc (FCarbPc)-targeting topical administration. Carbopol 934P was used to increase the F127 hydrogel adhesion on the skin. Rheological analyses showed that the Pc presented a low effect on the hydrogel matrix, changing the gelation temperature from 27.2 ± 0.1 to 28.5 ± 0.9 °C once the Pc concentration increases from zero to 1 mmol L^-1. The dermatological platform showed matrix erosion effects with the release of loaded Pc micelles. The permeation studies showed the excellent potential of the FCarb platform, which allowed the partition of the PS into deeper layers of the skin. The applicability of this dermatological platform in photodynamic therapy was evaluated by the generation of reactive species which was demonstrated by chemical photodynamic efficiency assays. The low effect on cell viability and proliferation in the dark was demonstrated by in vitro assays using L929 fibroblasts. The FCarbPc fostered the inhibition of Staphylococcus aureus strain, therefore demonstrating the platform's potential in the treatment of dermatological infections of microbial nature.

Susceptibility of Trichopyton mentagrophytes to Visible Light Wavelengths

OBJECTIVE

To determine whether a blue light (405 nm) could inhibit the growth of Trichopyton mentagrophytes without using a photosensitizing material as part of the treatment protocol.

DESIGN

Basic physiologic randomized trial using laboratory specimens (T mentagrophytes).

INTERVENTIONS/METHODS

Plated on a growth medium, T mentagrophytes were exposed to 3 to 5 administrations of blue light at 20 J/cm over 28 hours. Following 7 days of incubation, colony-forming units were counted and compared with nonirradiated controls.

RESULTS

The study found 3, 4, and 5 administrations of blue light produced significant inhibition of T mentagrophytes (P < .05); 4 and 5 applications produced the greatest inhibition of growth (84.7% and 93.6% kill rates, respectively).

CONCLUSIONS

The application of 405-nm light at a dose of 20 J/cm is an effective in vitro inhibitor of T mentagrophytes. To give results similar to those seen when a photosensitizing material is included, 3 to 5 applications of this wavelength and dose condition delivered over 28 hours is likely needed.

Distal and lateral toenail onychomycosis caused by Trichophyton rubrum: treatment with photodynamic therapy based on methylene blue dye

The study showed the effectiveness of photodynamic therapy based on methylene blue to treat severe distal and lateral subungual toenail onychomycosis. 22 patients were divided into two groups: group A consisting of 11 patients with severe toenail onychomycosis and group B consisting of 11 patients with mild-to-moderate toenail onychomycosis. All patients had onychomycosis caused by Trichophyton rubrum. The patients were treated with sessions of 2% methylene blue aqueous solution irradiated with light emission diode device with 630 nm and 36 J/cm2 biweekly for six months. The clinical response was significantly better in patients with mild-to-moderate (100%) onychomycosis compared with patients with severe onychomycosis (63.6%).

Endonyx toenail onychomycosis caused by Trichophyton rubrum: treatment with photodynamic therapy based on methylene blue dye

This study shows the effectiveness of photodynamic therapy based on methylene blue dye for the treatment of endonyx toenail onychomycosis. Four patients with endonyx onychomycosis caused by Trichophyton rubrum were treated with 2% methylene blue aqueous solution irradiated with light emission diode at 630 nm and an energy density of 36 J/cm2 for 6 months at 2-week intervals. The preliminary study showed the effectiveness of this therapy in the treatment of endonyx onychomycosis, and also indicated that the disease can be caused by T. rubrum.

An in vitro study of the photodynamic effect of rose bengal on Trichophyton rubrum

Onychomycosis, a fungal infection of the finger or toenails, is predominantly caused by Trichophyton rubrum. Treatment is difficult due to high recurrence rates and problems with treatment compliance. For these reasons, alternative therapies are needed. Here we describe the photoactivation of Rose Bengal (RB) using a green laser (λ = 532 nm) at fluences of 68, 133 and 228 J/cm(2) , and assess its fungicidal activity on T. rubrum spore suspensions. A 140 µM RB solution was able to induce a fungicidal effect on T. rubrum when photosensitized with the fluence of 228 J/cm(2) . RB photosensitization using a green laser provides a potential novel treatment for T. rubrum infections.

Silicon phthalocyanine 4 phototoxicity in Trichophyton rubrum

Trichophyton rubrum is the leading pathogen that causes long-lasting skin and nail dermatophyte infections. Currently, topical treatment consists of terbinafine for the skin and ciclopirox for the nails, whereas systemic agents, such as oral terbinafine and itraconazole, are also prescribed. These systemic drugs have severe side effects, including liver toxicity. Topical therapies, however, are sometimes ineffective. This led us to investigate alternative treatment options, such as photodynamic therapy (PDT). Although PDT is traditionally recognized as a therapeutic option for treating a wide range of medical conditions, including age-related macular degeneration and malignant cancers, its antimicrobial properties have also received considerable attention. However, the mechanism(s) underlying the susceptibility of dermatophytic fungi to PDT is relatively unknown. As a noninvasive treatment, PDT uses a photosensitizing drug and light, which, in the presence of oxygen, results in cellular destruction. In this study, we investigated the mechanism of cytotoxicity of PDT in vitro using the silicon phthalocyanine (Pc) 4 [SiPc(OSi(CH3)2(CH2)3N(CH3)2)(OH)] in T. rubrum. Confocal microscopy revealed that Pc 4 binds to cytoplasmic organelles, and upon irradiation, reactive oxygen species (ROS) are generated. The impairment of fungal metabolic activities as measured by an XTT (2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxyanilide inner salt) assay indicated that 1.0 μM Pc 4 followed by 670 to 675 nm light at 2.0 J/cm(2) reduced the overall cell survival rate, which was substantiated by a dry weight assay. In addition, we found that this therapeutic approach is effective against terbinafine-sensitive (24602) and terbinafine-resistant (MRL666) strains. These data suggest that Pc 4-PDT may have utility as a treatment for dermatophytosis.

An investigation into the inhibitory effect of ultraviolet radiation on Trichophyton rubrum

Fungal infection of nails, onychomycosis, is predominantly caused by Trichophyton rubrum. This infection is an important public health concern due to its persistent nature and high recurrence rates. Alternative treatments are urgently required. One such alternative is phototherapy involving the action of photothermal or photochemical processes. The aim of this novel study was to assess which wavelengths within the ultraviolet (UV) spectrum were inhibitory and equally important nail transmissible. Initial irradiations of T. rubrum spore suspensions were carried out using a tunable wavelength lamp system (fluence ≤3.1 J/cm(2)) at wavelengths between 280 and 400 nm (UVC to UVA) to evaluate which wavelengths prevented fungal growth. Light-emitting diodes (LEDs) of defined wavelengths were subsequently chosen with a view to evaluate and potentially implement this technology as a low-cost "in-home" treatment. Our experiments demonstrated that exposure at 280 nm using an LED with a fluence as low as 0.5 J/cm(2) was inhibitory, i.e., no growth following a 2-week incubation (p < 0.05; one-way ANOVA), while exposure to longer wavelengths was not. A key requirement for the use of phototherapy in the treatment of onychomycosis is that it must be nail transmissible. Our results indicate that the treatment with UVC is not feasible given that there is no overlap between the antifungal activity observed at 280 nm and transmission through the nail plate. However, a potential indirect application of this technology could be the decontamination of reservoirs of infection such as the shoes of infected individuals, thus preventing reinfection.