Efficacy Of Photodynamic Therapy In Treatment Research Articles

High Sensitivity Singlet Oxygen Luminescence Sensor Using Computational Spectroscopy and Solid-State Detector.

This paper presents a technique for high sensitivity measurement of singlet oxygen luminescence generated during photodynamic therapy (PDT) and ultraviolet (UV) irradiation on skin. The high measurement sensitivity is achieved by using a computational spectroscopy (CS) approach that provides improved photon detection efficiency compared to spectral filtering methodology. A solid-state InGaAs photodiode is used as the CS detector, which significantly reduces system cost and improves robustness compared to photomultiplier tubes. The spectral resolution enables high-accuracy determination and subtraction of photosensitizer fluorescence baseline without the need for time-gating. This allows for high sensitivity detection of singlet oxygen luminescence emission generated by continuous wave light sources, such as solar simulator sources and those commonly used in PDT clinics. The value of the technology is demonstrated during in vivo and ex vivo experiments that show the correlation of measured singlet oxygen with PDT treatment efficacy and the illumination intensity on the skin. These results demonstrate the potential use of the technology as a dosimeter to guide PDT treatment and as an analytical tool supporting the development of improved sunscreen products for skin cancer prevention.

Effect of Photobiomodulation on Protein Kinase Cδ, Cytochrome C, and Mitochondria in U87 MG Cells

Photobiomodulation (PBM) therapy is a relatively new modality for the combined treatment of cancer. Pre-treatment of certain types of cancer cells with PBM potentiates the treatment efficacy of photodynamic therapy (PDT). The mechanism of action of this synergetic effect is not yet fully understood. In the present study, we focused on protein kinase Cδ (PKCδ) as a proapoptotic agent that is highly expressed in U87MG cells. The distribution of PKCδ in the cytoplasm was changed and its concentration was increased by PBM using radiation at 808 nm (15 mW/cm2, 120 s). This process was accompanied by the organelle specific phosphorylation of PKCδ amino acids (serine/tyrosine). Enhanced phosphorylation of serine 645 in the catalytic domain of PKCδ was found in the cytoplasm, whereas the phosphorylation of tyrosine 311 was mainly localized in the mitochondria. Despite a local increase in the level of oxidative stress, only a small amount of cytochrome c was released from the mitochondria to cytosol. Although a partial inhibition of mitochondrial metabolic activity was induced in PBM-exposed cells, apoptosis was not observed. We hypothesized that PBM-induced photodamage of organelles was neutralized by autophagy maintained in these cells. However, photodynamic therapy may effectively exploit this behaviour to generate apoptosis in cancer treatment, which may increase the treatment efficacy and open up prospects for further applications.

IR780/Gemcitabine-conjugated metal-phenolic network enhanced photodynamic cancer therapy

Photodynamic therapy (PDT) is a clinically approved cancer treatment that uses energy of light to generate active substances that cause damage to the cancer. Photosensitizers are employed to absorb light and generate toxic reactive oxygen species (ROS) to damage biomolecules like DNA. At the same time, some chemotherapy drugs like nucleotide analogues can provide mechanism-guided promotion in the treatment efficacy of PDT. However, the photosensitizer and chemotherapy drugs used in PDT is usually organic molecules, which suffers from bad solubility, fast clearance, and acute toxicity. To achieve targeted treatment, a reasonable delivery system is necessary. Therefore, we reported a metal-phenolic network where IR780 and gemcitabine were coupled chemically to overcome these shortcomings. The enhanced PDT effects can be realized by the promoted cell death both in vitro and in vivo. Moreover, the synergistic therapy also induced T-cell mediated anti-tumor immune response, which was significant for the inhibition of distant tumor growth. This work expanded the biomedical application of metal-phenolic materials and contribute to the wider application of photodynamic cancer therapy.

On the need for standardized reporting of photophysical parameters of in vitro photodynamic therapy studies.

In vitro dose escalation experiments are one of the first gatekeepers in therapeutic evaluation and development. This also holds for evaluating novel photosensitizers (PS) and Photodynamic Therapy (PDT) co-therapies as needed to provide dose response guidelines before engaging in further pre-clinical studies. The dose needed to achieve 50% cell kill (LD50) is a standard metric to report the potency of a therapeutic agents that is widely accepted for single-drug therapies. In reporting results of PDT experiments, which involve delivery of both drug and light, it is inherently more complicated to identify such a convenient dose response metric that actually captures the larger space of treatment parameters. In addition to ubiquitous sources of biological variability that apply broadly in biomedical research, PDT treatment efficacy is determined by multiple key parameters that may or may not have been documented, including PS concentration and light fluence, where the latter is itself a function of the spectral properties of the light source used (often not described), not to mention dose rate, fractionation and other parameters that potentially vary between individual studies. It is impossible to compare results between two study when, for example one reports LD50 PS concentration without providing essential light dosimetry details. Motivated by this challenge in comparing outcomes and establishing reproducibility of in vitro PDT studies, we endeavored to perform a meta-analysis of the reporting of PDT results by converting, where possible, the disparately reported experimental details into a consistent metric that could be used to compare across studies. In this context we adopt here the number of photons absorbed by photosensitizers per unit volume to affect a 50% decline in cell survival as a standardized metric. By choosing this metric one can acknowledge the quantum-based generation of cytotoxins. While this metric does not cover every possible source of variability between any two studies, for a PS with known optical properties, this does encapsulate PS concentration as well as irradiance and spectral properties of light delivered. For the sake of focus we adopt this approach for study of reported results with two photosensitizers, Protoporphyrin IX, either synthesized in the cells by aminolevulinic acid or administered exogenously, and Chlorin e6. A literature search was performed to identify in vitro studies with these two photosensitizers and collect necessary information to calculate the absorbed photon LD50 threshold for each study. Only approximately 1/10 of the manuscripts reporting on in vitro studies provide the minimum required information to calculate the threshold values. While the majority of the determined threshold values are within a factor of 10, the range of threshold values spanned close to 7 orders of magnitude for both photosensitizers. To contrast with single-agent therapies, a similar exercise was performed for chemotherapeutic drugs targeting cellular mitosis or tyrosine kinase inhibitors resulted in an LD50 or IC50 range of 1-2 orders of magnitude, with LD50 or IC50 values for a single cell line being within a factor of 5. This review underscores challenges in the reporting of in vitro PDT efficacy. In many cases it takes considerable effort to extract the necessary methodology information to make meaningful comparison between PDT studies. Only when results between studies can be compared is it possible to begin to assess reproducibility which, as shown here, can be a major issue. Hence, guidelines need to be developed and enforced through the peer review process for meaningful reporting of preclinical PDT results in order for the most promising sensitizers and co-therapies to be identified and translated into the clinic.

Fully Automatic Prediction for Efficacy of Photodynamic Therapy in Clinical Port-Wine Stains Treatment: A Pilot Study

In this paper, we report a fully automatic method for the prediction of the treatment efficacy of photodynamic therapy during the clinical treatment in port-wine stains. Histogram of oriented gradients (HOG) features were extracted from optical coherence tomography images. Isolation forest (iForest) was used to build classifier based on these features, achieving a sensitivity of 84% and specificity of 91%. Our dataset consists of 336 PWS lesions of 121 patients. We aim to build a comprehensive computational model for the patients who respond positively to the photodynamic therapy, which could be used to sort and identify patients who respond poorly to photodynamic therapy before treatment and prevent them from unnecessary treatment.

Photodynamic Therapy for Metastatic Melanoma Treatment: A Review.

This review article is based on specifically targeted nanoparticles that have been used in the treatment of melanoma. According to the Skin Cancer Foundation, within 2017 an estimated 9730 people will die due to invasive melanoma. Conventional treatments for nonmalignant melanoma include surgery, chemotherapy, and radiation. For the treatment of metastatic melanoma, 3 therapeutic agents have been approved by the Food and Drug Administration: dacarbazine, recombinant interferon α-2b, and high-dose interleukin 2. Photodynamic therapy is an alternative therapy that activates a photosensitizer at a specific wavelength forming reactive oxygen species which in turn induces cell death; it is noninvasive with far less side effects when compared to conventional treatments. Nanoparticles are generally conjugated to photosynthetic drugs, since they are biocompatible, stabile, and durable, as well as have a high loading capacity, which improve either passive or active photosensitizer drug delivery to targeted cells. Therefore, various photosynthetic drugs and nanoparticle drug delivery systems specifically targeted for melanoma were analyzed in this review article in relation to either their passive or their active cellular uptake mechanisms in order to deduce the efficacy of photodynamic therapy treatment for metastatic melanoma which currently remains ongoing. The overall findings from this review concluded that no current photodynamic therapy studies have been performed in relation to active nanoparticle platform photosensitizer drug carrier systems for the treatment of metastatic melanoma, and so this type of research requires further investigation into developing a more efficient active nano-photosensitizer carrier smart drug that can be conjugated to specific cell surface receptors and combinative monoclonal antibodies so that a further enhanced and more efficient form of targeted photodynamic therapy for the treatment of metastatic melanoma can be established.

Dynamics of HPV viral loads reflect the treatment effect of photodynamic therapy in genital warts

Photodynamic therapy (PDT) has demonstrated good clinical cure rates and low recurrence rates in the treatment of genital warts. Human papillomavirus (HPV) genotypes and viral load assays can reflect the status of persistent or latent infection and serve as a predictor of infection clearance. Specimens from 41 patients with HPV infection were obtained, and the HPV genotypes and viral load were analyzed using real-time polymerase chain reaction (PCR) assays. Traditional treatment, such as radiofrequency, microwave, or surgical therapy, was used to remove the visible lesions, and then PDT treatment was performed every week. HPV DNA testing was performed at every patient visit and the frequency of PDT treatment was determined by changes in HPV viral loads. HPV viral loads decreased significantly after PDT treatment. There were significant differences in HPV viral loads between pretherapy and three or six rounds of PDT treatment. Significant differences were also observed between single and multiple type HPV infection after six rounds of PDT treatment. Patients with single type HPV infection had significantly higher rates of negative HPV DNA test results, as compared with patients with multiple infections after six rounds of PDT treatment; however, there was no difference in recurrence rates between the two groups. Dynamic monitoring of HPV genotypes and viral loads can be used to guide PDT treatment and indicate PDT treatment efficacy in eliminating HPV.

Enhancing Photodynamic Therapy treatment efficacy on oral cancer with Nimotuzumab

Enhancing Photodynamic Therapy treatment efficacy on oral cancer with Nimotuzumab

Applications and Efficacy of Photodynamic Therapy in Periodontics: A Review Study

Aims: Periodontitis is a common cause of tooth loss in adults and is an anaerobic bacterial infection. Enzymes, endotoxins and other cytotoxic bacterial products result in tissue destruction and initiation of chronic inflammation. Mechanical debridement by scaling and root planing (SRP) is the most effective treatment for this condition. Local delivery of antibiotics is an effective alternative treatment with less systemic side effects. Photodynamic therapy (PDT) is a technique of local delivery of antimicrobial agents. This study reviews the applications and efficacy of PDT for treatment of chronic and aggressive periodontitis. Place and Duration of Study: Sample: Department of periodontics, Shahid Beheshti University of Medical Sciences, Dental School, between June 2015 and April 2015. Methodology: A search was carried out in PubMed and Google Scholar using the keywords “photodynamic therapy” AND “chronic periodontitis” (MeSH), “photodynamic therapy” AND “aggressive periodontitis” and “photodynamic therapy” AND “periodontal treatment” (MeSH). English articles published from 2000 to 2015 were searched and a total of 32 papers including 8 articles on aggressive periodontitis and 24 on chronic periodontitis were found. Conclusion: PDT is a minimally invasive treatment for periodontal disease. Methodological Review Article Talebi and Taliee; BJMMR, 9(7): 1-10, 2015; Article no.BJMMR.18517 2 limitations of studies in this regard prevent a conclusion being drawn regarding the optimal efficacy of PDT as an adjunct for treatment of periodontitis.

Photodynamic therapy in treatment of oral lichen planus.

Oral lichen planus (OLP) is a relatively common chronic immunologic mucocutaneous disorder. Although there are many presenting treatments, some of them proved its failure. Recently, the use of photodynamic therapy (PDT) has been expanding due to its numerous advantages, as it is safe, convenient, and non-invasive and has toxic effect towards selective tissues. This article provides comprehensive review on OLP, its etiology, clinical features and recent non-pharmacological treatments. We also describe the topical PDT and its mechanisms. Our purpose was to evaluate the efficacy of PDT in treatment of OLP through collecting the data of the related clinical studies. We searched in PubMed website for the clinical studies that were reported from 2000 to 2014 using specific keywords: “photodynamic therapy” and “treatment of oral lichen planus”. Inclusion criteria were English publications only were concerned. In the selected studies of photodynamic treatment, adult patients (more than 20 years) were conducted and the OLP lesions were clinically and histologically confirmed. Exclusion criteria were classical and pharmacological treatments of OLP were excluded and also the using of PDT on skin lesions of lichen planus. We established five clinical studies in this review where all of them reported improvement and effectiveness of PDT in treatment of OLP lesions. The main outcome of comparing the related clinical studies is that the photodynamic is considered as a safe, effective and promising treatment modality for OLP.

Aminolevulinic acid-photodynamic therapy of basal cell carcinoma and factors affecting the response to treatment: A clinical trial

Background:Basal cell carcinoma (BCC) is the most common type of skin cancer in humans. Photodynamic therapy (PDT) is a non-invasive therapeutic modality that may be considered as a valuable treatment option for BCC. This study was designed with the aim of evaluating the efficacy of PDT in treatment of BCC and factors that may affect the response rate.Materials and Methods:This clinical trial was conducted on 12 patients (28 BCC lesions) who were treated with aminulevulinic acid (ALA)-PDT, monthly, up to 6 sessions and the clinical response, cosmetic results, and possible side effects were evaluated.Results:The study was performed on 28 BCC lesions from 12 patients. Complete response was achieved in 9 (32.1%) lesions. Complete response rate was higher in younger patients (P < 0.01) and those with smaller lesions (P < 0.001). Superficial type also had significant higher response rate (P < 0.05). Patients with history of radiotherapy for the treatment of tinea capitis in childhood showed less response (P < 0.05). Cosmetic results were excellent or good in 77.5% cases. After 6 months of follow-up, none of the resolved lesions recurred.Conclusion:PDT would be a good therapeutic option in treatment of BCC with acceptable efficacy and low side effects. Younger patients, superficial BCCs, and smaller lesions show better response to ALA-PDT. History of radiotherapy may be associated with a lower response rate.

Photodynamic therapy with verteporfin for polypoidal choroidal vasculopathy treatment: 3-year results in Taiwan

PurposeThe purpose of this study was to investigate the treatment efficacy of photodynamic therapy (PDT) with verteporfin for patients suffered from polypoidal choroidal vasculopathy. MethodsIn this retrospective comparative study, we included 25 eyes of 25 patients with macula-involved polypoidal choroidal vasculopathy. All patients had follow-up of more than 3 years. We compared the best-corrected visual acuity (BCVA) in logarithm of minimal angle of resolution (logMAR) scale at each follow-up time points with initial baseline BCVA. We also investigated the factors influencing final BCVA at the 36-month follow-up time point. ResultsAt 6 months, the mean BCVA improved from 0.77 to 0.68 (p = 0.024). All the mean BCVAs after the 6-month follow-up time points were still better than baseline mean BCVA, but the improvements were not significant statistically. The mean BCVAs became 0.68, 0.74, 0.75, 0.73, and 0.72 respectively at 12-month, 18-month, 24-month, 30-month, and 36-month follow-up time points. Better initial BCVA (p = 0.012) and smaller lesion size (p = 0.031) significantly predicted the better final visual improvement at 36 months rather than sex (p = 0.7) and age (p = 0.206). ConclusionAlthough the visual improvement after treatment of PDT with verteporfin was only temporarily significant, the prevention of visual deterioration in these patients persisted during a 3-year follow-up. Better initial BCVA and smaller lesion size were significant factors influencing final visual improvement, and early treatment might be suggested.

Knock down of the dual functional protein apurinic /apyrimidinic endonuclease 1 enhances the killing effect of hematoporphrphyrin derivative‐mediated photodynamic therapy on non‐small cell lung cancer cells in vitro and in a xenograft model

Photodynamic therapy (PDT) is considered to be effective treatment for many cancers including lung cancer, head and neck cancers, and prostate cancer. It uses the combination of nontoxic photosensitizers and harmless visible light to generate reactive oxygen species and kill cells. However, DNA repair and reactive oxygen species-induced signaling pathway activation play crucial roles in cellular response to PDT and may also result in therapeutic limitation of PDT. To improve the cancer therapeutic efficacy of PDT, we targeted apurinic/apyrimidinic endonuclease (APE1), which is essential for both DNA repair and redox regulation of gene transcription, as a potential candidate for PDT combined gene therapy. In our study, an adenovirus-mediated APE1 silencing strategy was introduced to test its therapeutic enhancement for the non-small cell lung cancer cell line A549 both in vitro and in vivo after hematoporphrphyrin derivative (HpD)-mediated PDT. The adenovirus vector Ad5/F35-shAPE1 was validated to significantly suppress the protein expression of APE1 in cultured A549 cell and in its xenograft of nude mice. Ad5/F35-shAPE1 effectively inhibited APE1 protein upregulation induced by PDT and resulted in an increase in A549 cell killing by photoirradiation compared with the hematoporphrphyrin derivative-PDT alone group. Ad5/F35-shAPE1 suppressed the DNA repair capacity for single-strand breaks and abolished the activation of some stress-related transcription factors such as hypoxia-induced factor (HIF)-1 that consequently lead to increased cell apoptosis after PDT. Additionally, knock down of APE1 enhanced the tumor suppression efficacy of PDT on the A549 xenograft. Our study indicated that APE1-targeted gene therapy combined with PDT is a promising strategy for enhancement of the efficacy of PDT in treatment of non-small cell lung cancer.

Therapeutic effects of a new photosensitizer for photodynamic therapy of early head and neck cancer in relation to tissue concentration

Objective Talaporfin sodium (Laserphyrin ®, Meiji Seika, Tokyo, Japan) is a second-generation photosensitizer developed in Japan. It is characterized by both mild and short-term skin photosensitivity. The objective of this study was to evaluate the efficacy and the pharmacokinetic characteristics in tumor tissues in patients with head and neck cancer. Methods (1) Four hours after administration intravenous injection of talaporfin sodium (40 mg/m 2), 100 mg tissue specimens were taken from the central part of the tumor. The samples were analyzed by reverse phase liquid chromatography and concentrations were measured. (2) Four hours after intravenous injection of talaporfin sodium (40 mg/m 2), we gave 60–150 J/cm 2 of 664 nm laser irradiation with a diode laser (PD laser, Panasonic, Japan). Biopsies were performed at 4 weeks and at 3 months after treatment and periodically thereafter to confirm the treatment efficacy of photodynamic therapy (PDT). Results Of the 14 patients who grope informed consent, more than 1 μg/g of talaporfin sodium was found in the tumor tissues in 13. Moreover, in 9 patients, tumor-to-normal-tissue ratios ranged from 2.32:1 to 5.69:1, which indicates that more than double the amount of talaporfin sodium was maintained within the tumor than in normal tissues. We have enrolled 22 patients with head and neck cancer with no clinically recognizable metastases after obtaining written informed consent to participate in this study. PDT using talaporfin sodium exhibited the equivalent efficacy to that of conventional PDT using hematoporphyrin derivative (HpD). Conclusions The results using a combination of talaporfin sodium and PD laser achieved a primary treatment outcome equivalent to that of conventional PDT. This method has also proven to be advantageous because of the reduced incidence of side effects such as photosensitivity and local edema.

Place of cryotherapy, brachytherapy and photodynamic therapy in therapeutic bronchoscopy of lung cancers

Cryotherapy, brachytherapy and photodynamic therapy (PDT) are three different methods proposed in the endoluminal treatment of lung cancers. The current article presents an overview of the specific indications and limits of each technique. These three methods were first proposed with palliative intent in inoperable patients with centrally located lung cancers. Now, the best indication is a curative intent in early stage lung cancers. Of the three, cryotherapy is the cheapest method. It induces cell necrosis in a 3-mm radius around the probe, and is suitable for treatment of superficial tumours. However, clinical trials are limited. In contrast, many clinical studies have confirmed the efficacy of PDT in treatment of superficial lung cancers. Brachytherapy can cure more aggressive tumours with deeper invasion into the bronchial wall. Unfortunately, no comparative studies have been published. Each of these methods induces a delayed tumour necrosis, and thus neither is indicated in the treatment of obstructive tumours with acute dyspnoea. In many situations, these methods should be complementary, particularly cryotherapy and brachytherapy or PDT and brachytherapy. The combination of these endoscopic methods with chemotherapy should be widely tested to promote the adjuvant role of the endoscopic methods in the treatment of lung cancers.