The biology of photodynamic therapy

Moore, James; West, Catharine M L; Whitehurst, Colin

doi:10.1088/0031-9155/42/5/012

Cited by 95 publications

(64 citation statements)

References 148 publications

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“…Similar observations were made by others using different cell lines and PDT protocols. 39 Obviously, generation of increased amounts of PpIX is essential for efficient PDT. However, T24 has only half the amount of total PpIX when compared to A431 (Fig.…”

Section: Cell-line Specific Responsesmentioning

confidence: 99%

Red versus blue light illumination in hexyl 5-aminolevulinate photodynamic therapy: the influence of light color and irradiance on the treatment outcomein vitro

et al. 2014

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Abstract. Hexyl 5-aminolevulinate (HAL) is a lipophilic derivative of 5-aminolevulinate, a key intermediate in biosynthesis of the photosensitizer protoporphyrin IX (PpIX). The photodynamic efficacy and cell death mode after red versus blue light illumination of HAL-induced PpIX have been examined and compared using five different cancer cell lines. LED arrays emitting at 410 and 624 nm served as homogenous and adjustable light sources. Our results show that the response after HAL-PDT is cell line specific, both regarding the shape of the dose-survival curve, the overall dose required for efficient cell killing, and the relative amount of apoptosis. The ratio between 410 and 624 nm in absorption coefficient correlates well with the difference in cell killing at the same wavelengths. In general, the PDT efficacy was several folds higher for blue light as compared with red light, as expected. However, HAL-PDT 624 induced more apoptosis than HAL-PDT 410 and illumination with low irradiance resulted in more apoptosis than high irradiance at the same lethal dose. This indicates differences in death modes after low and high irradiance after similar total light doses. From a treatment perspective, these differences may be important. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Section: Cell-line Specific Responsesmentioning

confidence: 99%

Red versus blue light illumination in hexyl 5-aminolevulinate photodynamic therapy: the influence of light color and irradiance on the treatment outcomein vitro

et al. 2014

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“…This method does not have the side effects such as decreased immunity, hair loss, pain, or mutations that can accompany conventional cancer treatments such as chemotherapy, surgery, or radiotherapy. [1][2][3][4][5][6][7] In addition, PDT has the advantage of being selective for cancer tissues, while organs and normal tissues are preserved in their original state. [8][9][10][11][12] The density of photosensitizers (PS) in a tumor, the excited photometric quantities injected into the tissue, and the amount of molecular oxygen in the organic tissue are factors that affect the results of photodynamic cancer treatment.…”

Section: Introductionmentioning

confidence: 99%

Reduction of thermal damage in photodynamic therapy by laser irradiation techniques

Lim

2012

J. Biomed. Opt

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Abstract. General application of continuous-wave (CW) laser irradiation modes in photodynamic therapy can cause thermal damage to normal tissues in addition to tumors. A new photodynamic laser therapy system using a pulse irradiation mode was optimized to reduce nonspecific thermal damage. In in vitro tissue specimens, tissue energy deposition rates were measured in three irradiation modes, CW, pulse, and burst-pulse. In addition, methods were tested for reducing variations in laser output and specific wavelength shifts using a thermoelectric cooler and thermistor. The average temperature elevation per 10 J∕cm 2 was 0.27°C, 0.09°C, and 0.08°C using the three methods, respectively, in pig muscle tissue. Variations in laser output were controlled within AE0.2%, and specific wavelength shift was limited to AE3 nm. Thus, optimization of a photodynamic laser system was achieved using a new pulse irradiation mode and controlled laser output to reduce potential thermal damage during conventional CW-based photodynamic therapy.

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“…Both necrosis and apoptosis result from PDT. Depending on the PS the relative effects of necrosis versus apoptosis vary and no clear cut answer can be derived from clonogenic cell survival curves [34]. Simple dose-response analyses are difficult to perform and to compare as uptake, photophysics (singlet oxygen quantum yield) and photodynamic action depend not only on the drug and cell type but also the light conditions (flux, wavelength, rate, etc.…”

Section: Biological Effects Of Pdtmentioning

confidence: 99%

Platelets, photosensitizers, and PDT

Senge

Radomski

2013

Photodiagnosis and Photodynamic Therapy

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SummaryPhotodynamic therapy (PDT) has both direct cell and indirect vascular effects. Both are well established and the latter has given rise to specifically target angiogenesis in PDT treatments. While the vascular effects are well understood, further advances in antiangiogenesis require a detailed understanding of PDT effects at the microvasculature level. Although some of the earliest investigations of PDT noted effects on platelet aggregation the importance of their interaction with endothelial cells and the crucial role of various signaling pathways is only now emerging. This review aims to give a general overview of PDT related studies on platelets, vascular effects, and their interaction with endothelial cells to indicate the potential for studies in this area.Abbreviations: ALA --aminolevulinic acid; AMD -age-related macular degeneration; ANET -anti-neovascular therapy; BGF -basic fibroblast growth factor; DHEdihaematoporphyrin ether; EDRF -endothelium-derived relaxing factor; epithelial growth factor -EGF; HIF-1 -hypoxia-inducible factor 1; HpD -haematoporphyrin derivative; IL -interleukin; PAF -platelet activating factor; PDT -photodynamic therapy; PS -photosensitizer; transforming growth factor 1 -TGF-1; TNF -tumor necrosis factor.

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The biology of photodynamic therapy

Cited by 95 publications

References 148 publications

Red versus blue light illumination in hexyl 5-aminolevulinate photodynamic therapy: the influence of light color and irradiance on the treatment outcomein vitro

Red versus blue light illumination in hexyl 5-aminolevulinate photodynamic therapy: the influence of light color and irradiance on the treatment outcomein vitro

Reduction of thermal damage in photodynamic therapy by laser irradiation techniques

Platelets, photosensitizers, and PDT

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