Photodiagnosis and Photodynamic Therapy - Articles in Press

What is the role of photodynamic therapy in the treatment of acne vulgaris? - Corrected Proof

Sally Ibbotson — 2012-02-10

Despite the efficacy of oral retinoids and antibiotics in the treatment of acne vulgaris, there remains the need for additional treatment options for selected patient groups such as those who are resistant, intolerant or unable to take conventional therapies. Improvement of acne vulgaris with visible light phototherapy is well documented and although the mechanism of action is unclear it is likely that anti-inflammatory, immunomodulatory and endogenous photodynamic therapy (PDT) effects are operative. However the place of PDT using exogenous photosensitisation in the treatment of acne requires clarification. In a Pubmed search of acne and PDT, 200 relevant articles were identified demonstrating the growing interest in this area. Few of these studies have investigated the role of PDT for severe acne, have made comparisons with existing therapies or have long term follow up. Indeed, it has recently been highlighted that the role of PDT for acne has been limited by a lack of optimisation of treatment regimes and data on longer term efficacy, a poor adverse effects profile and cost, and that PDT should not be considered as a first line approach . Early data exploring the role of PDT used regimes with prolonged periods of pro-drug application and irradiation at high dose and irradiance, resulting in destruction of sebaceous glands . We must therefore question is this something we want to achieve? Do we want to eradicate sebaceous glands? The answer is probably no. There is also a particular problem posed for the treatment of acne in patients of higher skin type, and this is highlighted by the article of Ding et al. . Overall, summarising the data from well-designed studies, PDT can result in improvement in inflammatory acne by 60–70% , and although there are isolated reports of improvement in comedonal acne it is generally not considered that PDT is appropriate for the non-inflammatory type of acne vulgaris. The optimal treatment regime is not established. There have been reports of many variables in the regime including the type of drug used: ALA, MAL, indole acetic acid, indocyanine green or methylene blue, and whether this is applied with or without occlusion, in a liposomal formulation or by injection, and there have been marked variables in terms of concentration and time of application of drug . Reduction to very low concentrations of drug for very short time periods may result in loss of efficacy . Furthermore, variables in light source have been reported: LED, IPL, pulsed dye laser; red light or blue light alone or in combination, and with variables in dose and irradiance . Indeed there are reports that light alone may be as effective as PDT . However, well designed studies have shown superiority of MAL PDT compared to placebo for patients with moderate to severe acne .

Local clinical phototreatment of herpes infection in São Paulo - Corrected Proof

Joao Paulo Tardivo, Mark Wainwright, Mauricio S. Baptista — 2012-02-10

Summary: The clinical use of topical photodynamic therapy in herpes simplex lesions in São Paulo is presented and discussed. Although previous attempts utilising this type of approach in the USA were discontinued in the early 1970s due to several presentations of post-treatment Bowen's disease, none of the cases from the clinic presented here have displayed any complications on follow-up. In addition, lesion recrudescence periods are generally much longer than with conventional approaches. This is thought to be due to improvements in the treatment protocol, viz. use of the non-toxic photosensitisers methylene blue and Hypericum perforatum extract in place of proflavine and neutral red in the original trials, differences in photosensitisation pathway and illumination of the treatment site with red rather than fluorescent/UV light. Post-treatment cosmesis is also excellent.

Optical properties of hematoporphyrin monomethyl ether (HMME), a PDT photosensitizer - Corrected Proof

2012-02-10

Summary: We report on some of the optical properties of Hemoporfin® (hematoporphyrin monomethyl ether, HMME), a photodynamic therapy (PDT) photosensitizer that has been in clinical trials in China since the early 1990s. We characterized the photosensitizer on the basis of one- and two-photon absorption and fluorescence emission. The effects of photobleaching were probed to characterize its decay kinetics. Additionally, we determined time resolved fluorescence and thermal effects on fluorescence and absorption properties.

Hyaluronic acid-functionalized mesoporous silica nanoparticles for efficient photodynamic therapy of cancer cells - Corrected Proof

2012-02-01

Summary: Mesoporous silica nanoparticles (MSN) for photodynamic therapy (PDT) were coated with poly-(l-lysine) and hyaluronic acid (HA) by using the layer-by-layer method. HA is able to target cancer cells over-expressing the corresponding CD44 receptor. MSN functionalized with HA (MSN-HA) were more efficient than MSN without the targeting moiety when PDT was performed at low fluence (14Jcm−2) and low dosage of MSN (20μgmL−1) on HCT 116 colorectal cancer cells, known to over-express the CD44 receptor. Incubation of HCT-116 cancer cells with an excess of HA impaired the PDT effect with MSN-HA thus demonstrating that an active endocytosis mechanism was involved in the uptake of MSN-HA by these cells.

Modulation of telomerase and signal transduction proteins by Hexyl-ALA-Photodynamic Therapy (PDT) in human doxorubicin resistant cancer cell models - Corrected Proof

Ellie S.M. Chu, Christine M.N. Yow — 2012-01-30

Summary: Aims: This study employed a doxorubicin resistant (MES-SA-Dx5) human uterine sarcoma cell line and its counterpart (MES-SA), to elucidate the efficacy of aminolevulinic acid-hexylester (hexyl-ALA) mediated PDT at molecular and transcriptional levels.Methods: Hexyl-ALA generated protoporphyrin IX in both cells were determined by molecular probes using Confocal Laser Scanning Microscopy. The hexyl-ALA-PDT induced signal transduction proteins and mode of cell death were quantitated by CASE™ ELISA assays and DAPI staining. The modulation of hTERT mRNA expression and telomerase activity were investigated by TaqMan real-time PCR and ELISA respectively. Hexyl-ALA-PDT mediated cell migratory effect was determined by wound-healing assay.Results: The results demonstrated that mitochondria were the major target of hexyl-ALA. At LD30, hexyl-ALA-PDT significantly provoked an up-regulation of phosphorylated p38MAPK and JNK proteins in both cells. Hexyl-ALA-PDT down-regulated hTERT (a catalytic subunit of telomerase) mRNA expression and showed a strong correlation with diminished telomerase activity in both cells (MES-SA: r2=0.9932; MES-SA-Dx5: r2=0.9775). The suppression of cell migratory effect in both cells was obtained after hexyl-ALA-PDT. Further, 50% and 30% of apoptotic cells were attained at LD50, for wild-type and drug resistant cells respectively. Unlike the wild-type, a higher PDT dose was crucial to induce apoptosis in the drug resistant cells.Conclusions: Our study provides the first evidence that p38MAPK and JNK kinases played a vital role in triggering hexyl-ALA-PDT-induced apoptosis, down-regulated hTERT mRNA expression and telomerase activity in both proposed cells. In vivo studies are worth examining for the benefit of clinical applications in drug resistant cancers and PDT development.

Treatment of Kimura disease with photodynamic therapy: A case study - Corrected Proof

Syedda Abbas, Waseem Jerjes, Tahwinder Upile, Anna Vincent, Colin Hopper — 2012-01-16

Summary: We report on the application of photodynamic therapy (PDT) in the management of Kimura disease. A 58-year-old Asian male was offered this modality to assess the possibility to control disease progression. The patient was managed with surgery and the disease recurred and caused facial disfigurement. PDT was offered after careful discussion at UCLH multidiscipline meeting. The photosensitiser “mTHPC” was introduced intravenously 96h prior to delivering the light under ultrasound guidance. Magnetic resonance images showed moderate-significant reduction of the disease volume. Fourteen months post-PDT, the disease started re-growing and the patient subsequently underwent one further round of PDT which was as successful as the first round in reducing the facial disfigurement. Photodynamic therapy was very effective in controlling disease progression in this patient who suffers from Kimura disease.

Evaluation of collagen alteration after topical photodynamic therapy (PDT) using second harmonic generation (SHG) microscopy – in vivo study in a mouse model - Corrected Proof

2012-01-16

Summary: Topical photodynamic therapy (PDT) mediated by 5-aminolevulinic acid (ALA) has been used for the treatment of age-related skin lesions for therapeutic or cosmetic purposes. The modulation of collagen component and structure might play a significant role in influencing treatment outcomes of PDT. In this study, the effect of multi-session low dose ALA PDT on skin rejuvenation was examined in a hairless mouse model. Changes in collagen and skin texture were investigated by histological examination and in vivo second harmonic generation (SHG) microscopy. Results indicated that multi-session PDT could improve the collagen density and arrangement of skin tissue. SHG microscopy combined with quantitative collagen analysis could provide a useful tool for the evaluation of collagen alteration induced by ALA PDT.

Comparison of cryotherapy and photodynamic therapy in treatment of oral leukoplakia - Corrected Proof

2012-01-16

Summary: Oral leukoplakia is a pre-malignant lesion of the oral mucosa. The aim of this study is to compare the curative effects of photodynamic therapy and cryotherapy in the treatment of oral leukoplakia. The first group, treated by photodynamic therapy (δ-aminolevulinic acid (ALA), 630–635nm wavelength), consisted of 48 patients suffering from leukoplakia. The second group consisted of 37 patients treated using cryotherapy. Analyses and comparisons of the complete responses, recurrences, numbers of procedures and adverse effects after both PDT and cryotherapy were obtained. In the first group, a complete response was obtained in 35 patients (72.9%), with thirteen recurrences observed (27.1%) over a six-month period. In the second group, a complete response was obtained in 33 patients (89.2%), and recurrence was observed in nine patients (24.3%). Photodynamic therapy and cryotherapy appear to be comparative methods of treatment that may both serve as alternatives for the traditional surgical treatment of oral leukoplakia. The advantages of PDT are connected with minimally invasive and localized character of the treatment and with not damage of collagenous tissue structures, therefore normal cells will repopulate these arrangements. PDT is more convenient for patients, less painful, and more esthetic.

Investigating the efficiency of novel metallo-phthalocyanine PDT-induced cell death in MCF-7 breast cancer cells - Corrected Proof

Tamarisk Kerry Horne, Heidi Abrahamse, Marianne J. Cronjé — 2012-01-16

Summary: Background: Cancer cells possess an innate resistance to inducers of the death program. Novel phthalocyanines with improved physiochemical properties harbor the potential for use in photodynamic therapy (PDT); a rising treatment alternative preferred for its mostly asymptomatic application and unique mechanism of action.Methods: This study aimed to determine whether in vitro PDT with two new metallo-phthalocyanines (metallo-Pcs), AlPcSmix and GePcSmix, are similarly effective in overcoming resistance to cell death in MCF-7 cells with a brief comparison to an established chemotherapeutic agent, etoposide. Optimum induction of cell death in these cancer cells was initially determined via measurement of cellular respiration and energy production levels. Indications of cytotoxicity and cell stress were evaluated and resultant levels compared to those in cells treated with etoposide.Results: Initial findings report AlPcSmix is predominantly more detrimental to cellular function and homeostasis when excited via red light irradiation of 15J/cm2. It appears GePcSmix requires higher dosage administrations to achieve similar responses within identical populations. However, due to the mechanism of PDT application, our findings indicate a greater toxic effect with both phthalocyanines when compared to etoposide of higher dosage within MCF-7 cells.Conclusion: Both phthalocyanines, despite similarity in structure, indicate induction of different cell death response pathways based on their toxicity potential. These therefore show great promise as potential PDT agents for the treatment of cancer.

Fluorescence examination and photodynamic therapy of facial squamous cell carcinoma—A case report - Corrected Proof

Xiaona Zhang, Jinzhang Chen, Yuling Luo, Lanying Zhang, Rongcheng Luo, Libo Li — 2012-01-09

Summary: Background and objective: To evaluate the usefulness and feasibility of fluorescence examination and photodynamic therapy (PDT) for facial squamous cell carcinoma.Methods: A 68-year-old male patient underwent 3 courses of PDT. The first treatment was carried out using topically applied 5-aminolevulinic acid (ALA) to the affected area (5.0cm×2.5cm) 3h before light irradiation. ALA/PpIX-mediated fluorescence was used to visualize the lesion and its margin. The lesion was illuminated with a 630nm laser at 120J/cm2. Thirty days later, the residual lesion received the second treatment at the same light dose after topical use of ALA. Despite the tumor was treated with two courses of PDT, The lesion was not cleared completely yet. At last we used topical ALA and intravenous injection of HiPorfin, with the same light dose, then the lesion was cured and the patient was tumor-free followed up for over 15 months.Results: ALA/PpIX-mediated fluorescence visualized the lesion location. Complete cure was achieved after the third course of ALA/Hiporfin PDT. During the 15 months of followed up, no recurrence was noticed.Conclusion: ALA assisted fluorescence examination can be a useful tool to visualize the malignant lesion and determine its margin. ALA-PDT is effective for superficial lesions, but for thicker and deeper lesions, systemic administration of photosensitizer is indispensable.

Pivotal roles of peptide transporter PEPT1 and ATP-binding cassette (ABC) transporter ABCG2 in 5-aminolevulinic acid (ALA)-based photocytotoxicity of gastric cancer cells in vitro - Corrected Proof

2012-01-05

Summary: Background: Recently, 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) is being widely used in cancer therapy owing to the tumor-specific accumulation of photosensitizing protoporphyrin IX (PpIX) after the administration of ALA. In the present study, by focusing on genes involved in the porphyrin biosynthesis pathway, we aimed to explore biomarkers that are predictive for the efficacy of ALA-PDT.Methods: We used five lines of human gastric cancer cells to measure the ALA-based photocytotoxicity. ALA-induced production of PpIX in cancer cells was quantified by fluorescence spectrophotometry. To examine the potential involvement of PEPT1 and ABCG2 in the ALA-PDT sensitivity, stable cell lines overexpressing PEPT1 were established and ABCG2-specific siRNA used.Results: We observed that three cell lines were photosensitive, whereas the other two cell lines were resistant to ALA-based photocytotoxicity. The ALA-based photocytotoxicity was found to be well correlated with intracellular PpIX levels, which suggests that certain enzymes and/or transporters involved in ALA-induced PpIX production are critical determinants. We found that high expression of the peptide transporter PEPT1 (ALA influx transporter) and low expression of the ATP-binding cassette transporter ABCG2 (porphyrin efflux transporter) determined ALA-induced PpIX production and cellular photosensitivity in vitro.Conclusion: PEPT1 and ABCG2 are key players in regulating intracellular PpIX levels and determining the efficacy of ALA-based photocytotoxicity against gastric cancer cells in vitro. Evaluation of the expression levels of PEPT1 and ABCG2 genes could be useful to predict the efficacy of ALA-PDT. Primers specific to those target genes are practical and useful biomarkers for predicting the photo-sensitivity to ALA-PDT.

The effects of PDT in primary malignant brain tumours could be improved by intraoperative radiotherapy - Corrected Proof

Matthew Lyons, Isaac Phang, Sam Eljamel — 2012-01-03

Summary: Introduction: GBM has a poor survival despite surgery and chemoradiotherapy. Cytoreduction and PDT have postulated to afford better local GBM-control. However, the interaction of PDT with newer novel therapies had not been fully investigated. This study reviewed the impact of PDT in conjunction with intraoperative radiotherapy.Methods: Case note review of prospectively collected data of GBMs treated surgically by the senior author (SE). Patients received standard therapy (ST), ST+PDT or ST+PDT+IORT. ST involved maximum safe resection, PDT involved intracavity 100J/cm2 630nm laser and IORT involved intracavity 10–15Gys using the PRS400®. Patients were followed up clinically and radiologically till death.Results: There were 73 patients included in this analysis (42 males). The average age was 59years. Thirty received PDT and 43 did not. The mean survival of PDT-patients was significantly longer than those had ST alone (62.9weeks vs. 20.6weeks) (p=0.001). Patients <65year of age survived longer than those ≥65year (p=0.033). IORT on its own did not make a significant difference to survival (p=0.111). However the average survival for patients who received PDT+IORT was substantially higher than those who received PDT alone (79weeks vs. 39.7weeks). Using a Cox regression covariant analysis, demonstrated that PDT was the only therapy to make a statistically significant difference to survival (p=0.018).Conclusions: PDT in high grade glioma was statistically significant therapeutic modality and its effects were further improved by IORT.

Elastic scattering spectroscopy in assessing skin lesions: An “in vivo” study - Corrected Proof

2011-12-29

Summary: Introduction: Elastic scattering spectroscopy (ESS) has been shown to be accurate in the identification of abnormalities of soft tissue. These include ischemia and inflammation, pre-cancer and cancer. The aim of this study was to compare findings of ESS with gold standard histopathology in patients with various skin lesions.Materials and methods: Seventy-three patients with clinically suspicious facial skin lesions were included. Those lesions with the surrounding innocuous skin were interrogated by ESS, biopsies were taken and examined histopathologically; the results were then compared.Results: The preliminary analysis showed obvious spectral differences between normal and pathological skin. Spectral differences were identified when comparing benign skin conditions to malignant ones. Spectral differences were identified between basal cell carcinomas and other skin lesions.Conclusions: This preliminary study shows that ESS can distinguish between normal, benign and malignant skin conditions.

Autofluorescence endoscopy with “real-time” digital image processing in differential diagnostics of selected benign and malignant lesions in the oesophagus - Corrected Proof

2011-12-26

Summary: Background: Oesophageal papilloma and Barrett's oesophagus are benign lesions known as risk factors of carcinoma in the oesophagus. Therefore, it is important to diagnose these early changes before neoplastic transformation.Method: Autofluorescence endoscopy is a fast and non-invasive method of imaging of tissues based on the natural fluorescence of endogenous fluorophores. The aim of this study was to prove the diagnostic utility of autofluorescence endoscopy with digital image processing in histological diagnosis of endoscopic findings in the upper digestive tract, primarily in the imaging of oesophageal papilloma.Results: During the retrospective analysis of about 200 endoscopic procedures in the upper digestive tract, 67 cases of benign, precancerous or cancerous changes were found. White light endoscopy (WLE) image, single-channel (red or green) autofluorescence images, as well as green and red fluorescence intensities in two modal fluorescence image and red-to-green (R/G) ratio (Numerical Colour Value, NCV) were correlated with histopathologic results. The NCV analysis in autofluorescence imaging (AFI) showed increased R/G ratio in cancerous changes in 96% vs. 85% in WLE. Simultaneous analysis with digital image processing allowed us to diagnose suspicious tissue as cancerous in all of cases. Barrett's metaplasia was confirmed in 90% vs. 79% (AFI vs. WLE), and 98% in imaging with digital image processing. In benign lesions, WLE allowed us to exclude tissue as malignant in 85%. Using autofluorescence endoscopy R/G ratio was increased in only 10% of benign changes causing the picture to be interpreted as suspicious, but when both methods were used together, 97.5% were cases excluded as malignancies. Mean R/G ratios were estimated to be 2.5 in cancers, 1.25 in Barrett's metaplasia and 0.75 in benign changes and were statistically significant (p=0.04).Conclusion: Autofluorescence imaging is a sensitive method to diagnose precancerous and cancerous early stages of the diseases located in oesophagus. Especially in two-modal imaging including white light endoscopy, autofluorescence imaging with digital image processing seems to be a useful modality of early diagnostics. Also in observation of papilloma changes, it facilitates differentiation between neoplastic and benign lesions and more accurate estimation of the risk of potential malignancy.

Antibacterial photodynamic therapy for dental caries: Evaluation of the photosensitizers used and light source properties - Corrected Proof

2011-12-26

Summary: Photodynamic therapy studies have shown promising results for inactivation of microorganisms related to dental caries. A large number of studies have used a variety of protocols, but few studies have analyzed photosensitizers and light source properties to obtain the best PDT dose response for dental caries. This study aims to discuss the photosensitizers and light source properties employed in PDT studies of dental caries. Three questions were formulated to discuss these aspects. The first involves the photosensitizer properties and their performance against Gram positive and Gram negative bacteria. The second discusses the use of light sources in accordance with the dye maximum absorbance to obtain optimal results. The third looks at the relevance of photosensitizer concentration, the possible formation of self-aggregates, and light source effectiveness. This review demonstrated that some groups of photosensitizers may be more effective against either Gram positive or negative bacteria, that the light source must be appropriate for dye maximum absorbance, and that some photosensitizers may have their absorbance modified with their concentration. For the best results of PDT against the main cariogenic bacteria (Streptococcus mutans), a variety of aspects should be taken into account, and among the analyzed photosensitizer, erythrosin seems to be the most appropriate since it acts against this Gram positive bacteria, has a hydrophilic tendency and even at low concentrations may have photodynamic effects. Considering erythrosin, the most appropriate light source should have a maximum emission intensity at a wavelength close to 530nm, which may be achieved with low cost LEDs.

Vascular targeted photodynamic therapy for bleeding gastrointestinal mucosal vascular lesions: A preliminary study - Corrected Proof

Haixia Qiu, Yongping Mao, Ying Gu, Ying Wang, Jianguo Zhu, Jing Zeng — 2011-12-19

Summary: Background: Vascular-targeted photodynamic therapy (V-PDT) has shown good selectivity and efficacy in the treatment of certain types of vascular disease, including port wine stains, age-related macular degeneration, and esophageal varices. This study was conducted to test the efficacy and safety of V-PDT in the treatment of gastrointestinal (GI) bleeding caused by the abnormal dilatation of capillaries.Methods: Patients with bleeding GI mucosal vascular lesions treated with V-PDT were included in this retrospective study. The efficiency of V-PDT was analyzed by comparing the documented endoscopy results, hemoglobin levels, and transfusion requirements before and at 6 months after the last V-PDT. Side effects during and after V-PDT and follow-up results were also analyzed.Results: Seven patients with bleeding GI mucosal vascular lesions were treated with V-PDT. After 1–4 V-PDT sessions, all patients no longer needed transfusions to maintain a stable hemoglobin level during the follow-up period of 6 months. The mean hemoglobin level of the seven patients improved from 6.21±1.48g/dl to 11.66±1.21g/dl (p<0.001), and the GI bleeding and melena of all the patients disappeared. No perforations, strictures, scars, or episodes of photosensitization occurred in the seven patients, and there were no recurrences of GI bleeding during the 1–21 months of further follow-up.Conclusions: This preliminary study indicated that V-PDT is a highly selective, safe, well-tolerated, and effective treatment modality for bleeding GI mucosal vascular lesions. However, prospective studies with larger sample sizes are needed to confirm this finding.

Phototoxicity of phenothiazinium dyes against methicillin-resistant Staphylococcus aureus and multi-drug resistant Escherichia coli - Corrected Proof

Nasim Kashef, Gita Ravaei Sharif Abadi, Gholamreza Esmaeeli Djavid — 2011-12-19

Summary: Background: Photodynamic inactivation (PDI) has been investigated to cope with the increasing incidence of multidrug-resistant (MDR) pathogens. Here we studied the PDI mediated by methylene blue (MB) and toluidine blue O (TBO) in clinical methicillin-resistant Staphylococcus aureus and MDR Escherichia coli, together with their corresponding American Type Culture Collection (ATCC) strains.Methods: Effect of photosensitizer concentration (12.5,25,50μg/ml) and laser irradiation time (10, 20 and 30min) on lethal photosensitization was investigated.Results: TBO was more effective. TBO at 50μg/ml, 46.8Jcm−2, exhibited 0.7log killing for MDR E. coli and 1.7log killing for E. coli (ATCC 25922); 3.1log killing for MRSA, and 4.2log killing for S. aureus (ATCC 25923). MB at 50μg/ml, 163.8Jcm−2, only exhibited 2.2log killing in MRSA and 3.1log killing in S. aureus (ATCC 25923). MB (50μg/ml, 163.8Jcm−2) induced 0.2log killing for MDR E. coli and 0.3log killing for E. coli (ATCC 25922). After TBO-PDI, MDR isolates were more susceptible to some antibiotics than control groups.Conclusion: Our studied clinical isolates were more resistant to PDI-mediated killing than their ATCC reference strains. Thus, TBO/MB-mediated PDI in other MDR isolates deserves further investigation.

Combination of Fospeg-IPDT and a natural antioxidant compound prevents photosensitivity in a murine prostate cancer tumour model - Corrected Proof

2011-12-15

Summary: Background: The aim of the present research was to investigate the potential use of a natural compound rich in antioxidant agents, derived from Pinus halepensis (P. halepensis), to prevent PDT induced photosensitivity. The present research progressed in two levels. The first one evolved the optimization of Fospeg-interstitial photodynamic therapy (IPDT) in a prostate cancer animal model. In the second one, P. halepensis bark extract, was evaluated for its potential use to prevent photosensitivity.Methods: Two sets of experiments were performed, IPDT only and IPDT in the presence of antioxidant. For both of them, Fospeg was administrated intravenously to SCID mice bearing prostate cancer, followed by IPDT after 6h. For the IPDT+antioxidant experiments, P. halepensis was injected intratumourously 1h prior the tumour illumination. Treatment outcome was monitored twice a week by an imaging system and by measuring tumour dimensions using a caliper. Photosensitivity was assessed by monitoring erythema of the tail using the imaging system.Results: IPDT with Fospeg and 15J total light energy is a therapeutic scheme that can eliminate tumours in the murine model of prostate cancer. Two months after complete tumour remission no tumour recurrence was observed. Also, the cosmetic outcome of the research was excellent. The major drawback of this treatment scheme was that 90% of the animals developed photosensitivity. The addition of P. halepensis bark extract resulted in prevention of the photosensitivity, leaving PDT outcome unaffected.Conclusions: The combined use of PDT and the used antioxidant agent could broaden the implementation of photodynamic therapy, by eliminating photosensitivity.

Monitoring microcirculatory alterations in oral squamous cell carcinoma following photodynamic therapy - Corrected Proof

2011-12-05

Summary: Background: One of the mechanisms through which photodynamic therapy (PDT) is thought to elicit tumour destruction is by producing microvascular damage and obstruction of nutritive blood flow. The aim of this study was to directly monitor and quantify microcirculatory changes following tissue illumination by PDT for oral squamous cell carcinoma.Methods: Ten consecutive patients receiving PDT for a carcinoma in situ, a T1 or T2 tumour in the oral cavity without evidence of lymph node metastasis were selected for this study. Tumour and marginal healthy mucosa total capillary density (TCD) and functional capillary density (FCD) inside the field of illumination were measured and compared using sidestream dark-field (SDF) imaging prior to tissue illumination, immediately after PDT, and again after 15min.Results: Baseline mean tumour TCD was 21.2±5capillaries per square millimetres (cpll/mm2) and 24.9±19cpll/mm2 in the surrounding marginal healthy tissue; there were no significant differences between tumour and healthy tissue or time points. Comparisons between baseline and post-illumination time points revealed significant differences in both tumour and healthy tissue FCD (P<0.05). No significant differences in FCD were observed between the two tissues.Conclusions: Our findings using SDF imaging demonstrate that PDT significantly attenuates tumour and marginal healthy tissue perfusion by directly disrupting the functionality of the microcirculation.

mTHPC – A drug on its way from second to third generation photosensitizer? - Corrected Proof

Mathias O. Senge — 2011-11-02

Summary: 5,10,15,20-Tetrakis(3-hydroxyphenyl)chlorin (mTHPC, Temoporfin) is a widely investigated second generation photosensitizer. Its initial use in solution form (Foscan®) is now complemented by nanoformulations (Fospeg®, Foslip®) and new chemical derivatives related to the basic hydroxyphenylporphyrin framework. Advances in formulation, chemical modifications and targeting strategies open the way for third generation photosensitizers and give an illustrative example for the developmental process of new photoactive drugs.

Research progress of Hemoporfin – Part one: Preclinical study - Corrected Proof

Yu Pu, Wenhui Chen, Zhengwei Yu — 2011-10-31

Summary: The second generation photosensitizer Hemoporfin (7(12)-(1-methoxyethyl) -12(7)-(1-hydroxyethyl)-3,8,13,17-tetramethyl-21H,23H-porphin-2,18-dipropionic acid) is a porphyrin derivative which processes a stable structure, high singlet oxygen yield, high photoactivity, low dark toxicity and fast clearance rate. Hemoporfin, also known as hematoporphyrin monomethyl ether (HMME) has been studied and used in photodynamic therapy (PDT) in China since 1989. This series of reports will provide an overview on the preclinical and clinical studies of this PDT photosensitizer. The first part of this series will highlight the results of preclinical studies that focused on the compound's optical characteristics, mechanism of the activities, pharmacological and toxicological properties.

Photodiagnosis and treatment of condyloma acuminatum using 5-aminolevulinic acid and homemade devices - Corrected Proof

2011-10-20

Summary: Background: The objective of this study was to improve the feasibility of applying topic 5-aminolevulinic acid (ALA) in photodiagnosis (PD) and treatment of condyloma caused by human papillomavirus (HPV) using two homemade handheld devices and to discuss the photodynamic therapy (PDT) as a suitable alternative for each of the cases studied. Both, protoporphyrin IX production and photodegradation were analyzed, and the pain experienced during the illumination was correlated with the light intensities. Methods: A total of 40 women with different grades of lesions caused by HPV were chosen from patients of the School of Medicine of Ribeirão Preto (University of Sao Paulo) and of the Unit of Public Health of Araraquara, Sao Paulo. Results: We did not encounter any unexpected difficulties using our devices during the treatment. The existence of an easily observable reddish fluorescence with large intensity concentrated on the lesions is the clinical indication of the penetration and the selective concentration of protoporphyrin IX in the clinical and subclinical lesions rather than in the healthy tissue. The aesthetic results were much better than those obtained by conventional techniques as surgery or cryogenics, with no recurrence reported after two years of treatment. Conclusions: Our results are proof for the various advantages using ALA cream for the PD and PDT in many different cases of condyloma by HPV. This study will be continued to investigate the PpIX photobleaching and the irradiance and fluence rate to optimize conducting the clinical trials, to improve the devices and therefore increase the treatment response.

Photodynamic therapy with hyperbranched poly(ether-ester) chlorin(e6) nanoparticles on human tongue carcinoma CAL-27 cells - Corrected Proof

2011-10-05

Summary: Background: Hyperbranched polymers represent a new class of drug-delivery vehicle that can be used to prepare nanoparticles with uniform size distribution.Methods: In this study we prepared covalent conjugates between the photosensitizer chlorin(e6) and hyperbranched poly(ether-ester), HPEE. HPEE–ce6 nanoparticles were synthesized by carbodiimide-mediated reaction between HPEE and ce6, and characterized by ultraviolet–visible absorption spectroscopy (UV–Vis), and transmission electron microscopy (TEM). The uptake and phototoxicity of HPEE–ce6 nanoparticles towards human oral tongue cancer CAL-27 cells was detected by confocal laser scanning microscopy (CLSM) and MTT assay, respectively.Results: The absorption peak of HPEE–ce6 nanoparticles was red-shifted 12-nm compared with ce6, and TEM showed uniform nanoparticles with a diameter of 50-nm. HPEE–ce6 nanoparticles were taken up by CAL-27 cells after 4h incubation and localized in the cytoplasm. The MTT assay showed a significantly (P<0.05) higher phototoxicity compared to free ce6 after 12J/cm2 of 660-nm laser illumination.Conclusions: This is the first time to our knowledge that hyperbranched polymers have been used in PDT drug delivery.

Depigmentation in melanomas increases the efficacy of hypericin-mediated photodynamic-induced cell death - Corrected Proof

Krishna V. Sharma, Lester M. Davids — 2011-10-05

Summary: Melanoma is the main cause of death in skin cancers. Despite combating with early detection, resection and post-operative therapy, melanoma treatment remains unsuccessful and investigations into other forms of adjuvant therapy such as photodynamic therapy (PDT) are prudent. This study proposes that depigmentation i.e. the removal of the free radical scavenging pigment, melanin, in melanotic melanoma cells increases their susceptibility to PDT-induced cell death. Two human melanoma cell lines: one pigmented (Mel-1) and one amelanotic (A375) cell lines were used. Kojic acid (KA), a tyrosinase-specific inhibitor, was optimised to 6μg/ml and shown to quantifiably inhibit melanin synthesis after a 3-day exposure. PDT on these cells resulted in a 3.82 fold increase of intracellular ROS production which correlated to 11% increase in cell death susceptibility compared to untreated controls. Moreover, cells allowed to regain their pigment failed to return to normal even after 72h thus proving the effectiveness of PDT. Using a DPPH* assay, the results confirmed the scavenging properties of melanin (IC50 18.30μg/ml) proving that this pigment may be one of the reasons for melanoma chemoresistance. Overall this study shows that pigment plays an important role in the efficacy of adjunctive PDT treatment and its removal enhances cell death susceptibility in melanomas.

Photodiagnosis and photodynamic therapy of peritoneal metastasis of ovarian cancer - Corrected Proof

Laurie Guyon, Manuel Ascencio, Pierre Collinet, Serge Mordon — 2011-10-03

Summary: Ovarian cancer is among the deadliest in women. Current treatment strategies fail to cure many patients owing to the difficulties of eradicating peritoneal implants frequently associated with this pathology. Photodynamic therapy represents a promising treatment as it offers many advantages over alternative strategies: diagnostic properties, specific targeting of abnormal cells, possibility to be combined with other therapies.

Mitoxantrone as a prospective photosensitizer for photodynamic therapy of breast cancer - Corrected Proof

2011-10-03

Summary: Photodynamic therapy has the potential to become an effective alternate to surgery for the treatment of cancer. In recent years, there has been a focus on identifying more effective and less toxic photosentisizers for use in photodynamic therapy. The purpose of this study was to assess the effectiveness of mitoxantrone, a chemotherapeutic agent, as a photosensitizer for photodynamic therapy in the MCF-7 human breast cancer cell line. Cytotoxicity was evaluated for different concentrations of mitoxantrone, and photosensitivity was assessed using a non-coherent light source. The percentage of the cell survival after 24h was investigated using the MTT assay. Overall, the results showed that mitoxantrone is a remarkably efficient photosensitizer that could mediate MCF-7 cell death at a low concentration (5μM) with modest exposure to light. It is surprising to find that a chemotherapeutic agent can be an effective photosensitizer for PDT in vitro.

Localization and phototoxic effect of zinc sulfophthalocyanine photosensitizer in human colon (DLD-1) and lung (A549) carcinoma cells (in vitro) - Corrected Proof

2011-09-19

Summary: Background: Photodynamic therapy (PDT) is a therapeutic modality used for treating cancerous cells. It has been previously shown that mixed sulfonated metallophthalocyanine complex, zinc sulfophthalocyanine (ZnPcSmix) is effective in destroying lung cancer cells. This study aimed to determine subcellular localization of ZnPcSmix and its effect on two cancer cell lines.Methods: ZnPcSmix was activated at a wavelength of 680nm with 5J/cm2. Colon (DLD-1) and lung (A549) cancer cell lines were used. Subcellular localization of ZnPcSmix was determined by fluorescence microscopy. Toxicity of PS alone and combination of light and PS (PDT) was determined by cell morphology, viability, proliferation and cytotoxicity. Cells which received no irradiation (0J/cm2), irradiation alone (5J/cm2) or treated with PS alone (no irradiation) served as controls.Results: ZnPcSmix localized in both lysozomes and mitochondria in both A549 and DLD-1 cells. A549 cells treated with PDT showed a significant decrease in viability and proliferation in all PS concentrations used, while in DLD-1 cells a significant decrease was seen with concentrations of 10, 20 and 40μM. In absence of light, ZnPcSmix did not result in cellular toxicity in A549 cells whereas in DLD-1 cells it resulted in a reduction in cell proliferation only at a concentration of 40μM.Conclusion: ZnPcSmix was effective in inducing cell death in both cell lines when localized in vital organelles such mitochondria and lysozomes which are essential for cell functioning. Photoactivated ZnPcSmix affected the cells at different concentration and yielded good therapeutic results in vitro.

In vitro photodynamic effect of aluminum tetrasulfophthalocyanines on melanoma skin cancer and healthy normal skin cells - Corrected Proof

K. Maduray, B. Odhav, T. Nyokong — 2011-08-08

Summary: Photodynamic therapy is a medical treatment that uses an inactive dye/drug and lasers as a light source to activate the dye/drug to produce a toxic form of oxygen that destroys the cancer cells. This study aimed at investigating the cytotoxic effects of different concentrations of aluminum tetrasulfophthalocyanines in its inactive and active state (laser induced) on melanoma skin cancer cells, healthy normal skin fibroblast and keratinocyte cells. Experimentally, 3×104cells/ml were seeded in 24-well plates before treatment with different concentrations of aluminum tetrasulfophthalocyanines. After 2h, cells were irradiated with a light dose of 4.5J/cm2. Post-irradiated cells were incubated for 24h before cell viability was measured using the CellTiter-Blue Viability Assay. Results showed that aluminum tetrasulfophthalocyanines at high concentrations were cytotoxic to melanoma cells in the absence of laser activation. In the presence of laser activation of aluminum tetrasulfophthalocyanines at a concentration of 40μg/ml decreased cell viability of melanoma cells to 45%, fibroblasts to 78% and keratinocytes to 73%. At this photosensitizing concentration of aluminum tetrasulfophthalocyanines the efficacy of the treatment light dose 4.5J/cm2 and the cell death mechanism induced by photoactivated aluminum tetrasulfophthalocyanines was evaluated. A light dose of 4.5J/cm2 was more efficient in killing a higher number of melanoma cells and a lower number of fibroblast and keratinocyte cells than the other light doses of 2.5J/cm2, 7.5J/cm2 and 10.5J/cm2. Apoptosis features such as blebbing, nucleus condensation, nucleus fragmentation and the formation of apoptotic bodies were seen in the photodynamic therapy treated melanoma skin cancer cells. This in vitro photodynamic therapy study concludes that using aluminum tetrasulfophthalocyanines at a photosensitizing concentration of 40μg/ml in combination with a laser dose of 4.5J/cm2 was potentially lethal for melanoma skin cancer cells and less harmful for the normal healthy skin cells.