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Author Spotlight: Exploring Photodynamic Therapy with Curcumin in a Murine Model for Oral Candidiasis
Published on: October 27, 2023
Photodynamic therapy of oral Candida infection in a mouse model
Fernanda Freire1, Cleber Ferraresi2, Antonio Olavo C Jorge3
1Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA; Department of Biosciences and Oral Diagnosis, Institute of Science and Technology, Universidade Estadual Paulista (UNESP), São José dos Campos, São Paulo, Brazil.
Abstract:
Species of the fungal genus Candida, can cause oral candidiasis especially in immunosuppressed patients. Many studies have investigated the use of photodynamic therapy (PDT) to kill fungi in vitro, but this approach has seldom been reported in animal models of infection. This study investigated the effects of PDT on Candida albicans as biofilms grown in vitro and also in an immunosuppressed mouse model of oral candidiasis infection. We used a luciferase-expressing strain that allowed non-invasive monitoring of the infection by bioluminescence imaging. The phenothiazinium salts, methylene blue (MB) and new methylene blue (NMB) were used as photosensitizers (PS), combined or not with potassium iodide (KI), and red laser (660nm) at four different light doses (10J, 20J, 40J and 60J). The best in vitro log reduction of CFU/ml on biofilm grown cells was: MB plus KI with 40J (2.31 log; p<0.001); and NMB without KI with 60J (1.77 log; p<0.001). These conditions were chosen for treating the in vivo model of oral Candida infection. After 5days of treatment the disease was practically eradicated, especially using MB plus KI with 40J. This study suggests that KI can potentiate PDT of fungal infection using MB (but not NMB) and could be a promising new approach for the treatment of oral candidiasis.
Insights
Photodynamic therapy (PDT) effectively treated oral candidiasis in mice using methylene blue (MB) and potassium iodide (KI). This combination significantly reduced fungal infections, showing promise for treating Candida albicans biofilms.
Area of Science:
- Mycology
- Photochemistry
- Infectious Diseases
Background:
- Oral candidiasis, often caused by Candida species, is a significant concern, particularly in immunocompromised individuals.
- Photodynamic therapy (PDT) shows potential for antifungal treatment, but its application in animal models of oral candidiasis is underexplored.
Purpose of the Study:
- To investigate the efficacy of PDT using phenothiazinium salts (methylene blue and new methylene blue) with or without potassium iodide against Candida albicans biofilms in vitro and in an immunosuppressed mouse model of oral candidiasis.
Main Methods:
- Candida albicans biofilms were treated with PDT using methylene blue (MB) or new methylene blue (NMB) as photosensitizers, with or without potassium iodide (KI), and a 660nm red laser at varying doses.
- An immunosuppressed mouse model of oral candidiasis was established and treated with optimized PDT conditions.
- Infection levels were monitored non-invasively using bioluminescence imaging of a luciferase-expressing Candida strain.
Main Results:
- In vitro, MB with KI at 40J yielded the highest log reduction (2.31) of viable Candida cells in biofilms.
- NMB without KI at 60J also showed significant reduction (1.77 log).
- In vivo, PDT, particularly MB with KI at 40J, led to near-complete eradication of oral candidiasis in mice after 5 days.
Conclusions:
- Potassium iodide can enhance the efficacy of PDT using methylene blue for treating fungal infections.
- PDT, especially with MB and KI, presents a promising therapeutic strategy for oral candidiasis.
