Skin fluorescence following photodynamic therapy with NPe6 photosensitizer

BackgroundThe second-generation photosensitizer NPe6 has strong anti-tumor effects with a much shorter photosensitive period than the first-generation photosensitizer Photofrin. Although photosensitive period has been reduced, skin photosensitivity is still a major side effect of photodynamic therapy (PDT). Therefore, we conducted a prospective study to investigate whether the NPe6 fluorescence intensity in skin after PDT could be measured effectively in human patients to improve the management of a patient's photosensitive period.MethodsThe NPe6 fluorescence measurements using a constructed fluorescence sensing system at the inside of the arm were acquired prior to and 5 and 10 min after NPe6 administration as well as at the time of PDT (4–5 h after administration), at discharge (2 or 3 days after PDT), and at 1 or 2 weeks after PDT. Participants were interviewed as to whether they had any complications at 2 weeks after PDT.ResultsNine male patients and one female patient entered this study. Nine patients were inpatients and one patient was an outpatient. All of the measurements of NPe6 fluorescence in the skin could be obtained without any complications. The spectral peak was detected at the time of discharge (2–3 days after administration) in most cases and it decreased at 1 or 2 weeks after PDT.ConclusionsThe fluorescence of NPe6 in the skin could be detected feasibly using the fluorescence sensing system in human patients. Measuring the relative concentration of NPe6 in the skin indirectly by measuring fluorescence intensity might be useful to predict the period of skin photosensitivity after PDT.     

Sub-additive effects of photodynamic therapy combined with erlotinib for the treatment of epidermoid carcinoma: An in vitro study

BackgroundPhotodynamic therapy (PDT) is an antitumour treatment that employs the combination of a photosensitive compound, oxygen and visible light. To improve the antitumour activity of PDT, the present study used the strategy of combining PDT with erlotinib (ERL), a drug frequently used in the treatment of epidermoid carcinoma.MethodsAn MTT cell viability assay was used to evaluate the cytotoxicity of PDT combined with ERL on A431 epidermoid carcinoma cells in vitro. This study evaluated the cytotoxicity of the following treatments: red laser irradiation (660 nm) at different power densities (1.25–180 J/cm²), the photosensitizer methylene blue (MB) at concentrations of 0.39–100 μM, PDT (12.5 μM MB and laser power densities from 1.25 to 180 J/cm²), and PDT (12.5 μM MB and a laser density of 120 J/cm²) plus ERL (1 μM).ResultsThe laser power densities that were tested showed no cytotoxicity in A431 cells. MB showed a dose-dependent cytotoxicity. In PDT, an increase in the dose of light resulted in an increase in the cytotoxicity of MB. In addition, there was a sub-additive effect between PDT and ERL compared to the effect of each therapy alone.ConclusionsThe sub-additive effect between PDT and ERL suggests that their combination may be an important strategy in the treatment of epidermoid carcinoma.     

Photodecomposition,photomutagenicity and photocytotoxicity of retinyl palmitate under He–Ne laser photoirradiation and its effects on photodynamic therapy of cancer cells in vitro

ObjectiveOur aim was to study photodecomposition, photomutagenicity and cytotoxicity of retinyl palmitate (RP), a principal storage form of vitamin A in humans and animals, under He–Ne laser photoirradiation. Moreover, the effect of different concentrations and timing protocol of antioxidants on photodynamic therapy (PDT) is contradictory, so the effect of RP (as antioxidant) on the PDT cytotoxicity was studied.MethodsPhotomutagenicity was tested by Ames test. Photodecomposition was studied by UV–vis spectroscopy. Cytotoxicity was measured with MTT-assay. Moreover, the effect of PDT, using hematoporphyrin derivatives (HpD) as photosensitizer under He–Ne laser irradiation (10 J/cm²), was studied on HeLa cells either with or without RP (1–100 μM) which incubated with the cells for short or long incubation period (1 h or 24 h) prior to PDT.ResultsNo photodecomposition of RP alone was obseved whereas there is a little photodecomposition of RP only in presence of HpD under irradiation with He–Ne laser. Moreover, no photomutagenicity was observed in Salmonella typhimurium strains under laser irradiation in presence or absence of HpD. RP alone (1–100 μM) significantly decrease the viability of HeLa cells. Laser irradiation of HeLa cells pre-incubated with RP alone for 24 h showed further significant decrease in viability of the cells. While RP incubations for 1 h before PDT had slight effect on the cells, 24 h incubation before PDT enhanced the cytotoxicity of PDT on HeLa cells.ConclusionsRP can be used 24 h before PDT to enhance its effects. RP is not mutagenic under irradiation with He–Ne laser.     

Photodynamic therapy using Photofrin and excimer dye laser treatment for superficial oral squamous cell carcinomas with long-term follow up

ObjectivesPhotodynamic therapy (PDT) is a very effective treatment for superficial malignancies that does not result in loss of normal tissue. Here, we report successful PDT treatment of superficial oral cancers and its clinical outcome with long-term follow up.Materials and methodsThirty-four superficial oral squamous cell carcinomas were treated with PDT, and the effects were evaluated. Each patient received Photofrin (2 mg/kg) intravenously 48 h prior to light irradiation. Photoradiation was performed at doses of 100–150 J/cm² using a 630-nm wavelength excimer dye laser.ResultsSix months after PDT, 30 patients (88.2%) showed complete responses while 9 patients (26.5%) had local relapses during long-term follow-up. The 5-year overall survival, disease-specific survival, and disease-free survival rates were 76.5%, 84.6%, and 63.3%, respectively. Lesions with red patches had a significantly higher recurrence rate than lesions with white patches. Accurate evaluation of the extent of lesions and appropriate photoradiation were important in improving outcomes. Adverse events observed included sunburn and sequestrum formation of alveolar bone. No abnormal laboratory values or systemic complications were observed.ConclusionPDT using Photofrin as the photosensitizer is an effective treatment modality for superficial oral carcinomas, with excellent healing and minimal side effects.     

Phototoxicity in a laryngeal cancer cell line enhanced by a targeting amphiphilic chlorin photosensitizer

BackgroundPhotodynamic therapy (PDT) has been established in several countries as an alternative therapy for the treatment of various malignancies. This therapy involves the incorporation of a photosensitizer (PS) that is activated by visible light and form reactive oxygen species leading to target cell death by apoptosis or necrosis. Previously, our group has demonstrated that CHL-T (semi-synthesized from chlorophyll a and containing a linked solubilizing group TRISMA^®) presented a pronounced potential to induce death in HeLa cell line after PDT. In the present study, besides confirm the high cytotoxicity in another cell line, we have further investigated the cell death mechanisms caused by CHL-T as a photosensitizer in laryngeal carcinoma cells.MethodsCells were exposed to different concentrations of three photosensitizers, namely, hypericin (HY), unmodified chlorin (CHL) and a synthesized amphiphilic chlorin derivative (CHL-T). PSs accumulation and localization were accessed by fluorescence assays. Photosensitization was induced at 6 J cm⁻² using red LEDs (630 ± 10 nm). Viability was assessed by mitochondrial function (MTT); whereas apoptosis/necrosis was evaluated by fluorescence microscopy and flow cytometry. Expression of pro-apoptotic p53 protein was studied by Western blot.Results and conclusionsAll PS showed similar localization profile in the HEp-2 cells. The use of CHL-T increased the percentage of apoptotic cells and also p53 expression in comparison with the use of HY and CHL as photosensitizers. This study shows a significant effect of CHLT associated with red light (630 ± 10 nm and 18 mW cm⁻²) irradiation on a cancer cell line, indicating the potential of this amphiphilic chlorin in enhancing the therapeutic effectiveness of Photodynamic Therapy (PDT).     

Methylene blue,curcumin and ion pairing nanoparticles effects on photodynamic therapy of MDA-MB-231 breast cancer cell

PurposeThe aim of current study was to use methylene blue-curcumin ion pair nanoparticles and single dyes as photosensitizer for comparison of photodynamic therapy (PDT) efficacy on MDA-MB-231 cancer cells, also various light sources effect on activation of photosensitizer (PS) was considered.MethodIon pair nanoparticles were synthesized using opposite charge ions precipitation and lyophilized. The PDT experiments were designed and the effect of PSs and light sources (Red LED (630 nm; power density: 30 mW cm⁻²) and blue LED (465 nm; power density: 34 mW cm⁻²)) on the human breast cancer cell line were examined. The effect of PS concentration (0–75 μg. mL⁻¹), incubation time, irradiation time and light sources, and priority in irradiation of blue or red lights were determined.ResultsThe results show that the ion pairing of methylene blue and curcumin enhance the photodynamic activity of both dyes and the cytotoxicity of ion pair nanoparticles on the MDA-231 breast cancer cell line. Blue and red LED light sources were used for photo activation of photosensitizers. The results demonstrated that both dyes can activate using red light LED better than blue light LED for singlet oxygen producing.ConclusionNano scale ion pair precipitating of methylene blue-curcumin enhanced the cell penetrating and subsequently cytotoxicity of both dyes together.     

Endobronchial photodynamic therapy under fluorescence control: Photodynamic theranostics

BackgroundPhotodynamic therapy (PDT) has several advantages. However, one of the disadvantages is its inability to be individualized according to biological characteristics of malignant tumors. The objective of this study was to investigate a strategy for individualized endobronchial PDT in the treatment of centrally located non-small cell lung cancer.MethodsNew approach suggests taking fluorescence-based measurements of chlorine E6 photosensitizer (PS) accumulation in the malignant tumor tissue, and assess PS consumption rate during PDT. Two randomized groups of 45 patients took part in the comparative study of standard PDT procedure, 662 nm, pulse-periodic mode, therapeutic light (reference group – RG) versus the investigated individualized approach under fluorescence control after irradiation with violet light, 408 nm, diagnostic light (study group – SG). The PDT-treatment parameters and results of follow-up bronchoscopy were compared between the groups.Results43 (96%) of 45 patients in SG demonstrated intense fluorescence in the area of the tracheal/bronchial tumor stenosis. 4 (9%) of 45 patients (SG) demonstrated fluorescence of mucosa areas distant from the main tumor lesion after violet light irradiation. Mean fluence during the whole PDT procedure was 95 ± 20 J/cm² (range 60–130 J/cm²), which was significantly lower than in RG (p = 0.01). Total exposure time was significantly lower in SG (365 ± 65 s), compared with RG (690 ± 65 s), P = 0.001. According to the follow-up bronchoscopy the difference in the PDT-treatment results between the groups is statistically insignificant.ConclusionsThe investigated strategy suggests using fluorescence control of the efficacy of PDT-treatment (photodynamic theranostics) to optimize and individualize the PDT procedure.     

Gonarthritis photodynamic therapy with chlorin e6 derivatives

BackgroundThe new methods of osteoarthritis treatment are in constant demand due to the complexity of the early diagnosis and therapy. Specific features of Сhlorin e6 derivative (Ce6) accumulation in knee joint tissues and the efficiency of photodynamic therapy (PDT) of gonarthritis were studied.MethodsThe experimental research was conducted on the model of posttraumatic gonarthritis on rabbits. The analysis of dynamics of change of Ce6 concentration in tissues of a knee joint was carried out by the method of fluorescent diagnostics. The intra-joint PDT was carried out using 662 nm laser with energy density of 120–150 J/cm² and a sapphire diffuser. An analysis of slices was conducted to confirm the anti-inflammatory effect through apoptosis.ResultsThe method of fluorescent spectroscopy revealed that the highest amount of Ce6 was accumulated in the synovial membrane of a damaged knee joint 2.5 h after its intravenous introduction. On 14th day after gonarthritis modeling but before PDT the synovial membrane showed signs of synovitis. On 21st day after PDT the synovial membrane possessed noticeable villous structure, and no cells of inflammatory nature were observed.ConclusionFluorescent diagnostics in knee joint tissues can be used in clinical practice of gonarthritis before, during and after PDT for monitoring the Ce6 accumulation and for treatment control. Optimal radiation energy density was determined to be 150 J/cm². In the studied time intervals (5–25 min) no dependency of PDT effect on irradiation time at the same energy density was observed. The analysis of results of clinical and morphological research shows that PDT is a low-invasive method of gonarthritis treatment with a high degree of efficiency and selectivity.     

In vitro effects of photodynamic therapy induced by chloroaluminum phthalocyanine nanoemulsion

BackgroundThe photodynamic therapy (PDT) has been used to treat cancer mainly by inducing oxidative stress. Our aim was to evaluate the effect of PDT and its combination with methoxyamine (MX), a blocker of base excision repair (BER), in cells expressing high levels of the APE1 protein, which is involved in cell oxidative damage response.MethodsThe HeLa and A549 cells were treated for 3 h with chloroaluminum phthalocyanine incorporated into a well-designed nanoemulsion (ClAlPc/NE); and then irradiated by visible light (@670 nm) with doses of 0.1, 0.5 and 1.0 J/cm². A simultaneous combination of MX + ClAlPc/NE was performed and then irradiated with the selected dose of 0.5 J/cm². The treatments were evaluated in terms of viability, clonogenicity, DNA fragmentation, and cell death mechanism by apoptosis and/or necrosis.ResultsThe APE1 protein expression observed was higher in HeLa than in A549. Both cell lines exhibited substantial differences in cell cytotoxicity. The PDT decreased the clonogenicity of HeLa by inducing apoptosis (sub-G1 and annexin detection). Additionaly, the MX potentiates the PDT-effects in HeLa. Otherwise, low cytotoxicity was observed in A549 cells.ConclusionThe PDT induced apoptosis in high APE1 expressive HeLa cells, and the blockage of BER by MX increased its effects.     

Efficacy of erythrosine and cyanidin-3-glucoside mediated photodynamic therapy on Porphyromonas gingivalis biofilms using green light laser

BackgroundThe purpose of this in vitro study was to evaluate the efficacy of erythrosine and cyanidin-3-glucoside as photosensitizers in PDT for the elimination of Porphyromonas gingivalis (P. gingivalis) biofilms.MethodsP. gingivalis biofilms were prepared from a chronic periodontitis subject. Erythrosine and cyanidin-3-glucoside were prepared and randomly allocated as follows: 110, 220, 330, and 440 μM erythrosine; 101, 202, 303, and 404 μM anthocyanin; and 440 μM erythrosine + 404 μM cyanidin-3-glucoside. There were 18 PDT experimental groups (non-irradiated/irradiated with a 532-nm green light diode laser at 1.29 J/cm² for 60 s). The 3 controls were grouped as follows: biofilms exposed to the photosensitizers alone, biofilms exposed to the laser alone, and biofilms exposed to 0.12% chlorhexidine. All sample groups were cultured at 1, 3 and 6 h after PDT and incubated in an anaerobic chamber at 37 °C for 4 days. The surviving fraction was calculated from the log₁₀ CFU/ml. The 330 and 440 μM erythrosine and the 440 μM erythrosine + 404 μM cyanidin-3-glucoside were mixed with spin traps (TEMPO, DMPO), and the electron spin resonance spectra were evaluated.ResultsThe log₁₀ CFU/ml measurements showed that the PDT groups with 330 μM or 440 μM erythrosine and 440 μM erythrosine + 404 μM cyanidin-3-glucoside had statistically significant differences from the other groups (one-way ANOVA and Bonferroni’s multiple comparison test, p- value ≤ 0.05).ConclusionsPDT using 330 μM erythrosine, 440 μM erythrosine or 440 μM erythrosine + 404 μM cyanidin-3-glucoside irradiated with the laser more effectively inhibited P. gingivalis in biofilms.     

A clinical evaluation of the efficacy of photodynamic therapy in the treatment of erosive oral lichen planus: A case series

BackgroundErosive oral lichen planus (EOLP) poses a substantial risk of malignant transformation into squamous cell cancer. The absence of established treatment gives way to alternative therapeutic strategies, including photodynamic therapy. The aim of the study was to evaluate the efficacy of PDT in the treatment of EOLP.MethodsTwelve female patients aged 63–80 with 22 OLP lesions (16 on the buccal mucosa, 6 on gingiva and tongue), underwent authors’ own PDT scheme with the use of 5% solution of 5-aminolevulinic acid (ALA) as photosensitizer. An ALA-saturated occlusive dressing was applied directly onto a lesion and surrounding mucosa 2 h prior to illumination with a custom-made diode lamp (light of 630 nm, dose of 300 mW). After a series of 10 weekly illumination sessions the patients were monitored for 12 months.ResultsThe mean size of lesions before treatment was 1.46 cm² ± 1.44. The lesions on the buccal mucosa were smaller (1.06 cm² ± 0.98) than those on the gingiva and tongue (2.63 cm² ± 1.93). Post-treatment improvement encompassed 16 lesions, 5 of which were in remission. The mean reduction in size after 10-session therapy was 8,05%. The healing continued and further reduction in size (by 69.13%) took place during the 12-month observation: 39.62% of lesions within the buccal mucosa and full remission of all lesions on the gingiva and tongue.ConclusionsThe results suggest that PDT offers non-invasive treatment of lesions in oral mucosa and may become an alternative and complementary method to those currently in use. Further studies involving larger groups of patients should be undertaken before it becomes routine practice.     

5-Aminolevulinic acid-based photodynamic therapy of chordoma: In vitro experiments on a human tumor cell line

BackgroundChordomas are very rare tumors of the skull base and the sacrum. They show infiltrating and destructive growth and are known to be chemo- and radio-resistant. After surgical resection, the recurrence rate is high and overall survival limited. As current adjuvant treatments are ineffective, new treatment concepts are urgently needed. 5-aminolevulinic acid-based photodynamic therapy (5-ALA based PDT) showed promising results for malignant gliomas. However, it is unknown so far, whether chordomas accumulate protoporphyrin IX (PPIX) after application of 5-ALA and whether they are sensitive to subsequent 5-ALA based PDT.MethodsThe immortalized human chordoma cells U-CH2 were used as in vitro model. After incubation for 4 h or 6 h with different 5-ALA concentrations, PPIX accumulation was determined by flow cytometry. To assess sensitivity to PDT, chordoma cells were incubated at 30.000 cells/well (high cell density) or 15.000 cells/well (low cell density) with graded doses of 5-ALA (0–50 μg/ml) in 96-well plates and subsequently exposed to laser light of 635 nm wavelength (18.75 J/cm²). Cell survival was measured 24 h after exposure to laser light using the WST-1 assay.ResultsU-CH2 cells dose-dependently accumulated PPIX (ANOVA; p < 0.0001). PPIX fluorescence was significantly higher, when cells were incubated with 5-ALA for 6 h compared to 4 h at higher 5-ALA concentrations (ANOVA/Bonferroni; p ≤ 0.05 for ≥ 30 μg/ml 5-ALA). For both cell densities, a 5-ALA dose-dependent decline in viability was observed (ANOVA; p < 0.0001). Viability was significantly lower at higher 5-ALA concentrations, when 30.000 cells/wells were treated compared to 15.000 cells/well (ANOVA/Bonferroni; p ≤ 0.001 for ≥ 30 μg/ml 5-ALA). LD50 was 30.25 μg/ml 5-ALA.ConclusionThe human UCH-2 cell line was a very useful in vitro model to study different effects of 5-ALA based PDT. For the first time, it could be shown that human chordoma cells may be destroyed by 5-ALA/PDT.     

Light source is critical to induce glioblastoma cell death by photodynamic therapy using chloro-aluminiumphtalocyanine albumin-based nanoparticles

Selection of an efficient light source is fundamental in the development of photodynamic therapy (PDT) protocols. However, few studies provide a comparison of different light sources with regard to phototoxic effects. Here, we compared the cell death induced by photoactivation of chloro-aluminiumphtalocyanine (AlClPc)-loaded human serum albumin nanoparticles under irradiation with different light sources: continuous laser (CL), pulsed laser (PL), and light-emitting diode (LED). Cells were exposed to three different AlClPc concentrations (1, 3, and 5 μM) and three different light doses (200, 500, and 700 mJ/cm²) for each light source. Cell death and differentiation of apoptosis and necrosis pathway were measured by flow cytometry. CL was the best light source for improving the photodynamic action of AlClPc-loaded albumin nanoparticles in glioblastoma cells and avoiding undesirable side effects, especially at low photosensitizer doses (200 mJ/cm²). In addition, apoptosis was the main cell death pathway in all evaluated cases (70% for CL, and greater than 50% for PL and LED). In conclusion, the search for optimal light sources and light/photosensitizer doses is a crucial step in improving PDT outcomes and enhancing the clinical translation of PDT.     

Photodynamic therapy in the management of basal cell carcinoma: Retrospective evaluation of outcome

IntroductionPhotodynamic therapy (PDT) is a relatively new method of treating various kinds of pathologies. In this retrospective study, a total of 148 patients with basal cell carcinoma (BCC) were treated with surface illumination methyl aminolevulinate – photodynamic therapy (MAL-PDT) or meta-tetrahydroxyphenylchlorin (mTHPC-PDT). Comparisons with the clinical features, rate of recurrence and overall outcome were made.Materials and methodsSurface illumination PDT was offered under local or general anaesthesia. For thin BCCs, the 16% strength cream (MAL) was applied topically 3 h prior to tissue illumination. A single-channel 628 nm diode laser was used for illumination and light was delivered at 100J/cm² per site. For thick BCCs, 0.05 mg/kg mTHPC was administered intravenously prior to tissue illumination. A single-channel 652 nm diode laser was used for illumination and light was delivered at 20J/cm² per site. Lesion response evaluation was carried out according to RECIST.ResultsThe MAL-PDT sub-group included 86 patients with 127 thin BCCs; 80 patients had complete response (CR) after one round of treatment. The mTHPC-PDT sub-group included 62 patients with 116 thick BCCs; 60 patients had complete response after one round of treatment. Statistically significant factors associated with complete response to MAL-PDT included superficial BCC histotype (P < 0.001), ≤0.5 mm tumour thickness (P < 0.001) and lack of ulceration (P < 0.001). While for the mTHPC-PDT sub-group, both superficial and nodular types responded significantly better than invasive type (P < 0.001); the lack of ulceration was insignificant factor in achieving complete response.ConclusionPDT achieved high efficacy in the treatment of basal cell carcinomas with greatly reduced morbidity and disfigurement. The technique is simple, can commonly be carried out in outpatient clinics, and is highly acceptable to patients.     

In vitro evaluation of adhesion/proliferation of human gingival fibroblasts on demineralized root surfaces by toluidine blue O in antimicrobial photodynamic therapy

BackgroundAntimicrobial photodynamic therapy (aPDT) in Dentistry has important effects as bacterial destruction in areas with periodontal disease. Some dyes applied in aPDT could present low pH and, consequently, result in tooth demineralization. This study evaluated demineralization produced by aPDT with toluidine blue O (TBO) at low pH and analyzed adhesion/proliferation of human gingival fibroblasts (HGF).MethodsIn the 1st phase, bovine enamel and root dentin fragments received 2 treatments: PDT4 group (TBO–100 μg/ml—pH 4–60 s) plus laser (660 nm, 45 J/cm², 1.08 J, 30 mW, 30 s, spot 0.024 cm², 1.25 W/cm², sweeping, non-contact) and CA group (citric acid plus tetracycline—pH 1–180 s). Surface hardness loss and tooth wear were statistically analyzed (Student’s t test, ANOVA/Tukey, p < 0.05). In the 2nd phase, human dentin fragments were divided in C (control group—scaling and root planing), PDT4 and CA. HGF (10⁴, 5th passage) were cultured on these fragments for 24, 48 and 72 h and counted in scanning electron microscopy photographs. Number of HGF was analyzed using repeated-measures ANOVA and Tukey (p < 0.05).ResultsPercentage of surface hardness loss was similar in dentin for PDT4 (71.5%) and CA (76.1%) (p > 0.05) and higher in enamel for CA (68.0%) compared to PDT4 (34.1%) (p < 0.05). In respect to wear, no difference was found between PDT4 (dentin: 12.58 μm, enamel: 12.19 μm respectively) and CA (dentin: 11.74 μm and enamel: 11.03 μm) (p > 0.05). Number of HGF was higher after 72 h in CA group (2.66, p < 0.05) compared to PDT4 (2.2) and C (1.33).ConclusionPDT4 is not as aggressive as CA for enamel. However, dentin demineralized promoted by PDT4 does not stimulate HGF adhesion and proliferation as CA.     

Photodynamic therapy using methylene blue in lung adenocarcinoma xenograft and hamster cheek pouch induced squamous cell carcinoma

BackgroundPhotodynamic therapy (PDT) is used to treat early proximal bronchial cancer during a flexible bronchoscopy. The technique relies on the excitation of a photosensitizer by an appropriate wavelength, which is delivered into the bronchus in close contact with the tumor.ObjectiveTo assess methylene blue (MB) as a PDT agent for the treatment of respiratory tract cancer in animal models.MethodsMB-induced PDT was performed on 7 subcutaneous NCI-H460 lung adenocarcinoma xenografts in nude mice and 9 induced squamous cell cancer in the hamster cheek pouch model. In mice, PDT was carried out on right-sided tumors after intratumoral injection of methylene blue 1% (w/v) and illumination at 630 nm at 200 J/cm (Diomed PDT 630), with the left tumor used as control (illumination alone or MB alone). The tumoral volume was assessed before and 15 days after PDT.ResultsFourteen xenografts were treated in mice, including seven treated with MB-PDT, producing a 52% mean tumor volume regression (1568 mm³ vs. 544 mm³) compared to seven control cases in which tumor volume increased (p = 0.007; Mann-Whitney test). Nine cheek pouch induced carcinomas were treated in the hamster group, with a mean volume decrease of 85.8% (from 44.8% to 100%) (initial mean volume = 210 mm³ vs. post PDT mean volume = 97 mm³). Histology analysis showed 4/9 complete responses.ConclusionIntratumoral MB appears efficient as PDT agent for cancer treatment in animal models. Further studies are needed to assess the safety and efficacy of MB-associated PDT for the treatment of lung cancer in humans.     

Clinical efficacy of photodynamic therapy adjunctive to scaling and root planing in the treatment of chronic periodontitis: A systematic review and meta-analysis

PurposeTo evaluate the clinical efficacy of photodynamic therapy (PDT) adjunctive to scaling and root planing (SRP) in patients with untreated chronic periodontitis based on up-to-date evidence.MethodsMEDLINE and the Cochrane Library were systematically searched to identify eligible randomized controlled trials (RCTs), supplemented by a manual literature search. Mean differences (MD) and the corresponding 95% confidence intervals (CI) of probing depth (PD) reduction and clinical attachment level (CAL) gain were synthesized. The I² test and Q statistics were used to determine the inter-study heterogeneity. Subgroup analysis based on smoking status was performed.ResultsEleven RCTs with a total of 243 subjects were included. Significant improvement in PD reduction (MD = 0.13, CI:0.02–0.24, p = 0.02) and marginal significant improvement in CAL gain (MD = 0.18, CI:−0.005–0.363, p = 0.056) were observed in favor of SRP+PDT at 3 months. When evaluated at 6 months after baseline, the association of PDT with SRP resulted in a significant benefit in PD reduction (MD = 0.40, CI:0.05–0.74, p = 0.03), but not in CAL gain (MD = 0.37, CI:−0.18–0.93, p = 0.18). Subgroup analysis revealed that the combined therapy produced no significant improvements in PD and CAL at neither 3 months nor 6 months for studies with smokers. No treatment-related adverse events or side effects had been reported by the included studies.ConclusionsPooled analysis suggests a short-term benefit of PDT as an adjunct to SRP in clinical outcome variables. However, evidence regarding its long-term efficacy is still insufficient and no significant effect has been confirmed in terms of CAL gain at 6 months. Future clinical trials of high methodological quality are needed to establish the optimal combination of photosensitizer and laser configuration.     

Evaluation of photodynamic therapy on fibroblast viability and cytokine production

BackgroundThe aim of this study was to evaluate the effects of photodynamic therapy with curcumin (PDT) comparatively to 5% sodium hypochlorite (NaOCl) and saline solution on cell viability and cytokine (IL-1β and IL-6) production by mouse fibroblasts.MethodsSixty seconds of pre-irradiation time with curcumin 500 mg/L and Led wavelength (λ) 480 nm, 72 J cm², for 300 s was used for PDT. Solutions were diluted in culture medium DMEM (1 × 10⁴ cells) and placed into 24-well cell culture plates with mouse fibroblasts L-929. Culture medium was used as control. After 6, 24 and 48 h, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay (MTT) was used to evaluate the cell viability and the supernatant was collected for cytokine evaluation using enzyme-linked immunosorbent assay (ELISA). The results were statistically analyzed by ANOVA and BonFerroni correction (p < 0.05) for MTT and Kruskal–Wallis test and Dunn (p < 0.05) for ELISA.ResultsPDT and saline solution presented low cytotoxic effect similar to the control group (p > 0.05) while 5% NaOCl was more cytotoxic than PDT (p < 0.05) in all periods of time. All materials similarly expressed IL-1β and IL-6 regardless to the experimental period (p < 0.05).ConclusionsPDT with curcumin was not cytotoxic to L929 fibroblasts differently from 5% NaOCl. In all groups occurred similar expression of IL-1β and IL-6.     

Irradiance dependence of the conduction block of an in vitro cardiomyocyte wire

BackgroundTo obtain therapeutic condition precisely by in vitro experiment, we studied the irradiance dependence of the electrical conduction blockage caused by a photodynamic reaction using a high extracellular concentration of talaporfin sodium on a novel in vitro cardiomyocyte electrical conduction wire.MethodsThe cardiomyocyte wires were constructed on patterned cultivation cover glass, which had cultivation areas 60 μm in width, and a maximum length of 10 mm. The talaporfin sodium concentration was set to 20 μg/mL. The photodynamic reaction with a high extracellular photosensitizer concentration was performed with a short time interval (approximately 15 min) between photosensitizer exposure and irradiation. A 663-nm laser was applied to the cardiomyocyte wire, and the irradiance was varied between 3 and 120 mW/cm². The cardiomyocyte electrical conduction was evaluated using the cross-correlation function of intracellular Ca²⁺ probe fluorescence brightness from an upper and lower section outside the laser irradiation area of a wire every 10 s, which lasted up to 600 s.ResultsThe onset of electrical conduction blockage was defined by an 85% decrease in the cross-correlation function, compared with its initial value. The time for the electrical conduction blockage decreased from 600 to 300 s as the irradiance was increased. Also, the probability of electrical conduction blockage was found to increase with increasing irradiance.ConclusionsWe found a strong dependence on the irradiance for the time and probability of electrical conduction blockage.     

Fluorescence analysis of a tumor model in the chorioallantoic membrane used for the evaluation of different photosensitizers for photodynamic therapy

The development of a tumor in the chicken chorioallantoic membrane (CAM) enables a more individualized understanding of the dynamics of the photosensitizer (PS) interaction with the tumor blood vessels and cells. Photogem^® and 5-aminolevulinic acid (ALA), a protoporphyrin IX (PpIX) precursor, were used as PS and their red fluorescence enabled the monitoring of PS dynamic distribution in the vessels and in the tumor. With a tumor model in CAM and fluorescence assessment, the aim of this study was to evaluate the PDT parameters comparing different photosensitezers. In this model, the topical application was chosen as the best way of drug delivery and widefield fluorescence images were at every 30 min. The images were processed in a MATLAB^® routine for a semi-quantitative analysis of the red fluorescence. PpIX formation in the blood vessels and in the tumor region was observed after 3 h and 1.5 h, respectively, whereas Photogem^® was accumulated in the tumor region after 2 h. The illumination was performed by a diode laser with emission centered at 635 nm and irradiance of 80 mW/cm² for 10 min. After PDT irradiation, the photobleaching for both compounds was observed. Photogem^® showed a reduced photobleaching, however, both PS induced a destruction of the tumor mass and vascular network in the treated area.