Antimicrobial Photodynamic Therapy mediated by Photodithazine® in the treatment of denture stomatitis: A case report

Photodynamic therapy in the coadjuvant treatment of Sporothrix schenckii complex

INTRODUCTION

Sporotrichosis, a zoonosis caused by animal, mainly cat, scratches or bites, is caused by fungi belonging to the Sporothrix complex. Treatment usually consists in antifungal administration, although treatment failure and hepatotoxicity reports have been noted. Alternative sporotrichosis treatment methods, such as antimicrobial photodynamic therapy (aPDT), may, therefore, be indicated.

CASE REPORT

In this context, this study followed a 56-year-old male renal transplanted patient displaying disseminated sporotrichosis, presenting erythematous skin lesions with ulcerated backgrounds and hardened consistency on the nose, oral and scalp. The lesions were present for about 2 months and the patient coexisted with cats. Intravenous amphotericin B administration was initiated, and immunosuppression was suspended. Seven aPDT sessions were also performed in 48 h intervals on the oral lesions, employing 0.01% methylene blue gel as the photosensitizing agent. After the 4th aPDT session, the patient was discharged, amphotericin B administration was suspended, and the treatment was continued with itraconazole, without immunosuppression. Red laser was applied to the oral lesions after the 7th aPDT session. Significant lesion improvement was observed after the final aPDT session and complete palate lesion repair was noted after two red laser sessions.

CONCLUSION

These findings indicate that aPDT is a valuable strategy as an adjunct sporotrichosis treatment.

Therapeutic efficacy of adjunctive photodynamic therapy in the treatment of denture stomatitis

BACKGROUND

The present report assessed the efficacy of curcumin-mediated photodynamic therapy (CUR-mediated PDT) as an adjunct to antifungal gel treatment by evaluating the salivary interleukin-6 (IL-6) and matrix metalloproteinases-8 (MMP-8) levels together with Candida species counts in denture stomatitis (DS) patients.

METHODS

In total, 50 DS subjects were randomly categorized into 2 groups: Group-1: subjects who received the antifungal gel treatment and Group-2: participants who received CUR-mediated PDT. The Sabourad Dextrose Agar and CHROMAgar were utilized for evaluating Candida species counts, while the Enzyme-Linked Immunosorbent Assay was employed to estimate the salivary levels of IL-6 and MMP-8. All clinical evaluations were performed at the baseline, 1 month, and 2 months.

RESULTS

In total, group-2 subjects showed a significant decrease in Candida albicans (C. albicans) counts on both follow-ups (i.e., 1-month and 2-month) than group-1 participants. C. krusei count also reduced in group-2 subejcts than group-1 participants at the 2nd follow-up as compared to the baseline, nevertheless, a slight increase in C. krusei count was noticed in group-2 subjects at the 2nd follow-up than the 1st follow-up. The salivary IL-6 and MMP-8 levels in both groups reduced significantly at both follow-ups than the baseline. According to the stepwise logistic regression analysis, no statistically significant correlation was observed between Candida species count and other parameters such as age and gender of the patient, duration of DS, and frequency of treatment(s).

CONCLUSION

CUR-mediated PDT is an efficaciousness therapeutic modality for alleviating Candida species counts on the surface of denture and the palatal mucosa, as well as improving the salivary IL-6 and MMP-8 levels in DS patients.

Efficacy of Rose Bengal and Curcumin mediated photodynamic therapy for the treatment of denture stomatitis in patients with habitual cigarette smoking: A randomized controlled clinical trial

BACKGROUND

Cigarette smoking in conjugation with bad oral hygiene is considered a typical predisposing factor for many oral diseases including denture stomatitis. This study investigated the effect of Rose Bengal (RB)-and Curcumin (CUR)-mediated photodynamic therapy (PDT) in comparison with nystatin therapy in the intervention of denture stomatitis in cigarette smokers.

METHODS

Overall, 45 habitual cigarette smokers aged ~58 years having denture stomatitis were categorized into three groups: Group-I - RB-mediated PDT, Group-II - CUR-mediated PDT, and Group-III - Nystatin therapy. The primary outcome of the interest was: counts of Candida colony from denture surface and palatal mucosa, calculated as CFU/mL, whereas the prevalence of Candida species determined in 3 research groups comprised the secondary outcome. Oral swab specimens were gathered from the denture surfaces and palatal mucosa. All clinical assessments were performed at baseline, 6 weeks, and 12 weeks.

RESULTS

C. albicans was the most prevalent yeast identified on both denture surfaces and palatal mucosa, followed by C. tropicalis and C. glabrata. A considerable decrease in the CFU/mL scores were observed in Group-I and Group-II at the end of the interventions and on the 12-week follow-up (p<0.05). Group-I, II, and III demonstrated clinical efficacy rates of 53%, 51%, and 49%, respectively.

CONCLUSION

CUR-and RB-mediated PDT was found to be as effective as topical Nystatin therapy for the intervention of denture stomatitis among cigarette smokers.

Efficiency of Antimicrobial Photodynamic Therapy with Photodithazine® on MSSA and MRSA Strains

Staphylococccus aureus is a ubiquitous and opportunistic bacteria associated with high mortality rates. Antimicrobial photodynamic therapy (aPDT) is based on the application of a light source and a photosensitizer that can interact with molecular oxygen, forming Reactive Oxygen Species (ROS) that result in bacterial inactivation. This study aimed to analyze, in vitro, the action of aPDT with Photodithazine^® (PDZ) in methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) strains. The strains were incubated with PDZ at 25, 50, 75, and 100 mg/L for 15 min and irradiated with fluences of 25, 50, and 100 J/cm². The internalization of PDZ was evaluated by confocal microscopy, the bacterial growth by counting the number of colony-forming units, as well as the bacterial metabolic activity post-aPDT and the production of ROS. In both strains, the photosensitizer was internalized; the production of ROS increased when the aPDT was applied; there was a bacterial reduction compared to the control at all the evaluated fluences and concentrations; and, in most parameters, it was obtained complete inactivation with significant difference (p < 0.05). The implementation of aPDT with PDZ in clinical strains of S. aureus has resulted in its complete inactivation, including the MRSA strains.

Natural Photosensitizers in Antimicrobial Photodynamic Therapy

Health problems and reduced treatment effectiveness due to antimicrobial resistance have become important global problems and are important factors that negatively affect life expectancy. Antimicrobial photodynamic therapy (APDT) is constantly evolving and can minimize this antimicrobial resistance problem. Reactive oxygen species produced when nontoxic photosensitizers are exposed to light are the main functional components of APDT responsible for microbial destruction; therefore, APDT has a broad spectrum of target pathogens, such as bacteria, fungi, and viruses. Various photosensitizers, including natural extracts, compounds, and their synthetic derivatives, are being investigated. The main limitations, such as weak antimicrobial activity against Gram-negative bacteria, solubility, specificity, and cost, encourage the exploration of new photosensitizer candidates. Many additional methods, such as cell surface engineering, cotreatment with membrane-damaging agents, nanotechnology, computational simulation, and sonodynamic therapy, are also being investigated to develop novel APDT methods with improved properties. In this review, we summarize APDT research, focusing on natural photosensitizers used in in vitro and in vivo experimental models. In addition, we describe the limitations observed for natural photosensitizers and the methods developed to counter those limitations with emerging technologies.

Gene expression of Candida albicans strains isolates from patients with denture stomatitis submitted to treatments with photodynamic therapy and nystatin

The study evaluated the effect of antimicrobial photodynamic therapy (aPDT) and nystatin (NYS) in the expression of genes (ACT1, ALS1, CAP1, CAT1, EFG1, HWP1, LIP3, PLB1, SAP1, and SOD1) involved in the virulence of Candida albicans strains recovered from patients with denture stomatitis (DS). These strains were isolated from the patients before (initial) and after treatment (final), and 45 days after the treatments (follow-up). For gene expression analyses, RNA was isolated from the clinical strains, followed by cDNA synthesis and qPCR using specific primers for each target gene. The samples that present integrity were pooled to increase the RNA yield. In the end, four patients treated with aPDT and five patients treated with NYS had the clinical isolates of C. albicans submitted to gene expression evaluation. The data demonstrated a statistical difference in the expression of PLB1 and ACT1 for the different therapies (aPDT versus NYS). Also, there was a statistical difference in the expression of CAT1, SOD1, and LIP3 at the time intervals assessed (initial, final, and follow-up). In contrast, no statistical difference was found in the expression of ALS1, HWP1, EFG1, CAP1, CAT1, SOD1, LIP3, and SAP1 between the therapies, while no significant difference was detected at the time intervals evaluated for ALS1, HWP1, EFG1, CAP1, and SAP1. Therefore, the topical treatments for DS with aPDT or NYS did not effect the expression of most C. albicans virulence genes evaluated.

Treatment of oral fungal infections using photodynamic therapy: Systematic review and meta-analysis

OBJECTIVES

This systematic review evaluated the evidence for the effectiveness of Photodynamic therapy (PDT) in treating oral fungal infections, as an alternative to conventional antifungal medications.

METHODS

Five randomized control trials (168 participants) comparing the treatment of oral fungal infections using met with our inclusion criteria. Clinical and microbiological improvement was assessed by random-effects meta-analysis. Methodological quality assessment and heterogeneity were performed using peer-reviewed criteria. PROSPERO registration: CRD42017076.

RESULTS

PDT showed statistically non-significant increased clinical efficacy (risk ratio (RR) = 1.47 [95% confidence interval (CI), 0.68; 3.17]; three studies, n = 108 participants, I² = 50%) and mycological efficacy (mean difference (MD) = 0.54 [95%CI, -0.71; 1.79]; three studies, n = 100; I² = 39%) at 30 days, as compared with conventional antifungal therapy. Lack of standardization of treatment parameters and variability in the assessment of outcomes was observed across the studies. All included studies had a moderate to low risk of bias.

CONCLUSIONS

PDT showed comparable effectiveness at treating oral fungal infections, particularly denture stomatitis. The small number of studies in this review, small sample size and variability of methods and outcome measures across studies, highlight the need for more standardized studies with longer follow-up periods to enable recommendation of PDT as an alternative to conventional antifungal therapy.

Innovations for prevention and care of oral candidiasis in HIV-infected individuals: Are they available?-A workshop report

Oral candidiasis (OC) is the most prevalent HIV-related oral lesion in patients on combined anti-retroviral therapy (cART) or without cART. Management is challenged in some patients by development of resistance to azole drugs, such as fluconazole. Recent scientific knowledge about OC pathogenesis, the role of OC in the immune reconstitution inflammatory syndrome (IRIS), the relationship of OC with the microbiome, and novelties in OC treatment was discussed in an international workshop format. Literature searches were conducted to address five questions: (a) Considering the pathogenesis of Candida spp. infection, are there any potential therapeutic targets that could be considered, mainly in HIV-infected individuals resistant to fluconazole? (b) Is oral candidiasis part of IRIS in HIV patients who receive cART? (c) Can management of the oral microbiome reduce occurrence of OC in patients with HIV infection? (d) What are the recent advances (since 2015) regarding plant-based and alternative medicines in management of OC? and (e) Is there a role for photodynamic therapy in management of OC in HIV-infected patients? A number of the key areas where further research is necessary were identified to allow a deeper insight into this oral condition that could help to understand its nature and recommend alternatives for care.

Effectiveness of mechanical debridement with and without antimicrobial photodynamic therapy against oral yeasts in children with gingivitis undergoing fixed orthodontic therapy

OBJECTIVE

The aim was to assess the effectiveness of mechanical debridement (MD) and antimicrobial photodynamic therapy (aPDT) against oral yeasts in children with gingivitis undergoing fixed orthodontic therapy (FOT).

METHODS

Individuals undergoing orthodontic treatment were included. Patients were randomly divided into 2-groups. In the test-group, patients underwent MD with adjuvant aPDT; and in the control-group, patients underwent MD alone. Demographic information was recorded using a questionnaire. An ultrasonic scaler was used to perform MD and aPDT was done using methylene blue and visible light. In both groups, gingival index, unstimulated whole salivary flow rate and oral yeasts counts were measured at baseline and compared at 6-months' follow-up. Group comparisons were performed and P < 0.05 was selected as an indicator of statistical significance.

RESULTS

Eighteen (10 males and 8 females) and 18 individuals (9 males and 9 females) were included in the test- and control groups. The mean age of individuals in the test and control groups were 16.6 ± 0.5 and 16.8 ± 0.4 years, respectively. At 6-months' follow-up, the GI was comparable among patients in the test- and control-group. In the test-group, the CFU/ml of oral yeasts were significantly higher at baseline compared with 6-months' follow-up (P < 0.05). In the control-group, there was no statistically significant difference in the CFU/ml of oral yeasts at baseline and 6-months' follow-up.

CONCLUSION

aPDT is a useful adjuvant to MD in reducing whole salivary oral yeasts counts among adolescents undergoing orthodontic treatment. In the sort-term, MD with and without aPDT is useful in reducing GI in adolescents undergoing orthodontic treatment.

The in vitro Photoinactivation of Helicobacter pylori by a Novel LED-Based Device

The rise of antibiotic resistance is the main cause for the failure of conventional antibiotic therapy of Helicobacter pylori infection, which is often associated with severe gastric diseases, including gastric cancer. In the last years, alternative non-pharmacological approaches have been considered in the treatment of H. pylori infection. Among these, antimicrobial PhotoDynamic Therapy (aPDT), a light-based treatment able to photoinactivate a wide range of bacteria, viruses, fungal and protozoan parasites, could represent a promising therapeutic strategy. In the case of H. pylori, aPDT can exploit photoactive endogenous porphyrins, such as protoporphyrin IX and coproporphyrin I and III, to induce photokilling, without any other exogenous photosensitizers. With the aim of developing an ingestible LED-based robotic pill for minimally invasive intragastric treatment of H. pylori infection, it is crucial to determine the best illumination parameters to activate the endogenous photosensitizers. In this study the photokilling effect on H. pylori has been evaluated by using a novel LED-based device, designed for testing the appropriate LEDs for the pill and suitable to perform in vitro irradiation experiments. Exposure to visible light induced bacterial photokilling most effectively at 405 nm and 460 nm. Sub-lethal light dose at 405 nm caused morphological changes on bacterial surface indicating the cell wall as one of the main targets of photodamage. For the first time endogenous photosensitizing molecules other than porphyrins, such as flavins, have been suggested to be involved in the 460 nm H. pylori photoinactivation.

Antimicrobial Photodynamic Therapy in Combination with Nystatin in the Treatment of Experimental Oral Candidiasis Induced by Candida albicans Resistant to Fluconazole

Background: It has been demonstrated that azole-resistant strains of Candida albicans have a greater resistance to antimicrobial photodynamic therapy (aPDT) when compared to their more susceptible counterparts. For this reason, the present study evaluated the efficacy of aPDT, together with nystatin (NYS), in the treatment of oral candidiasis in vivo. Methods: Mice were infected with fluconazole-resistant C. albicans (ATCC 96901). To perform the combined therapy, aPDT, mediated by Photodithazine (PDZ) and LED light, was used together with NYS. The efficacy of the treatments was evaluated by microbiological, macroscopic, histopathological and Confocal Scanning Laser Microscopy analyses of the lesions. The expression of p21 and p53, proteins associated with cell death, from the tongues of mice, was also performed. Results: The combined therapy reduced the fungal viability by around 2.6 log₁₀ and decreased the oral lesions and the inflammatory reaction. Additionally, it stimulated the production of p53 and p21. Conclusions: The combined therapy is a promising alternative treatment for oral candidiasis induced by C. albicans resistant to fluconazole.

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.

Chitosan-Based Drug Delivery Systems for Optimization of Photodynamic Therapy: a Review

Drug delivery systems (DDS) can be designed to enrich the pharmacological and therapeutic properties of several drugs. Many of the initial obstacles that impeded the clinical applications of conventional DDS have been overcome with nanotechnology-based DDS, especially those formed by chitosan (CS). CS is a linear polysaccharide obtained by the deacetylation of chitin, which has potential properties such as biocompatibility, hydrophilicity, biodegradability, non-toxicity, high bioavailability, simplicity of modification, aqueous solubility, and excellent chemical resistance. Furthermore, CS can prepare several DDS as films, gels, nanoparticles, and microparticles to improve delivery of drugs, such as photosensitizers (PS). Thus, CS-based DDS are broadly investigated for photodynamic therapy (PDT) of cancer and fungal and bacterial diseases. In PDT, a PS is activated by light of a specific wavelength, which provokes selective damage to the target tissue and its surrounding vasculature, but most PS have low water solubility and cutaneous photosensitivity impairing the clinical use of PDT. Based on this, the application of nanotechnology using chitosan-based DDS in PDT may offer great possibilities in the treatment of diseases. Therefore, this review presents numerous applications of chitosan-based DDS in order to improve the PDT for cancer and fungal and bacterial diseases.

Comparison of the efficacy of indocyanine green-mediated photodynamic therapy and nystatin therapy in treatment of denture stomatitis

BACKGROUND

Candida species have an influence in the pathogenesis of denture stomatitis. The current study aimed to investigate the efficacy of indocyanine green (ICG)-mediated photodynamic therapy (PDT) in combination with nystatin mouthwash (PDT + nystatin) for the treatment of denture stomatitis in comparison with routine antifungal therapy with nystatin alone.

METHODS

In this double-blind randomized clinical trial, 66 patients were randomly assigned into PDT + nystatin (n = 33) and nystatin (n = 33) groups, both groups were treated 3-times a day (15 days) with nystatin mouthwash, and PDT was performed twice once a week for the PDT + nystatin group. Briefly, ICG was applied on the palatal lesion and laser irradiation was performed using a diode laser (810 nm, 56 J/cm²). Nystatin group was also treated with sham laser in order to eliminate the possible psychological effects. The clinical and mycological evaluations were carried out at the baseline, during treatment, and the end of follow-up. Patients who completed the treatment and follow-up were eligible for statistical analysis (each group 28 cases).

RESULTS

Patient treatment with nystatin or PDT + nystatin reduced the lesions extension. Candida species were isolated from all patients and the number of Candida CFU in both groups showed a significant reduction at each post-treatment visit; however, the mean reduction achieved in the PDT + nystatin group was significantly higher than nystatin alone.

CONCLUSIONS

ICG-mediated PDT in combination with nystatin mouthwash can improve the clinical feature of denture stomatitis with no adverse effects; therefore, it could be used as an alternative to the currently available antifungal therapy using nystatin alone.

Antimicrobial photodynamic therapy alone or in combination with antibiotic local administration against biofilms of Fusobacterium nucleatum and Porphyromonas gingivalis

Antimicrobial photodynamic therapy (aPDT) kills several planktonic pathogens. However, the susceptibility of biofilm-derived anaerobic bacteria to aPDT is poorly characterized. Here, we evaluated the effect of Photodithazine (PDZ)-mediated aPDT on Fusobacterium nucleatum and Porphyromonas gingivalis biofilms. In addition, aPDT was tested with metronidazole (MTZ) to explore the potential antimicrobial effect of the treatment. The minimum inhibitory concentration (MIC) of MTZ was defined for each bacterial species. Single-species biofilms of each species were grown on polystyrene plates under anaerobic conditions for five days. aPDT was performed by applying PDZ at concentrations of 50, 75 and 100 mg/L, followed by exposure to 50 J/cm² LED light (660 nm) with or without MTZ. aPDT exhibited a significant reduction in bacterial viability at a PDZ concentration of 100 mg/L, with 1.12 log₁₀ and 2.66 log₁₀ reductions for F. nucleatum and P. gingivalis in biofilms, respectively. However, the antimicrobial effect against F. nucleatum was achieved only when aPDT was combined with MTZ at 100× MIC. Regarding P. gingivalis, the combination of PDZ-mediated aPDT at 100 mg/L with MTZ 100× MIC resulted in a 5 log₁₀ reduction in the bacterial population. The potential antimicrobial effects of aPDT in combination with MTZ for both single pathogenic biofilms were confirmed by live/dead staining. These results suggest that localized antibiotic administration may be an adjuvant to aPDT to control F. nucleatum and P. gingivalis biofilms.

Antimicrobial photodynamic therapy - what we know and what we don't

Considering increasing number of pathogens resistant towards commonly used antibiotics as well as antiseptics, there is a pressing need for antimicrobial approaches that are capable of inactivating pathogens efficiently without the risk of inducing resistances. In this regard, an alternative approach is the antimicrobial photodynamic therapy (aPDT). The antimicrobial effect of aPDT is based on the principle that visible light activates a per se non-toxic molecule, the so-called photosensitizer (PS), resulting in generation of reactive oxygen species that kill bacteria unselectively via an oxidative burst. During the last 10-20 years, there has been extensive in vitro research on novel PS as well as light sources, which is now to be translated into clinics. In this review, we aim to provide an overview about the history of aPDT, its fundamental photochemical and photophysical mechanisms as well as photosensitizers and light sources that are currently applied for aPDT in vitro. Furthermore, the potential of resistances towards aPDT is extensively discussed and implications for proper comparison of in vitro studies regarding aPDT as well as for potential application fields in clinical practice are given. Overall, this review shall provide an outlook on future research directions needed for successful translation of promising in vitro results in aPDT towards clinical practice.