Effects of Photodynamic Therapy on Tumor Oxygenation

描述：该项目的目标是量化氧气， 光敏剂在肿瘤中的分布，描述光动力学的影响 光动力疗法（PDT）对这些分布的影响，并测量对肿瘤的影响 反应PDT的照明光对肿瘤氧的消耗已经被证实， 被认为是潜在的治疗限制。研究这种氧的方法 消耗包括极谱针探针测量组织PO（2） 和血氧浓度的光谱测定。肿瘤平均 氧浓度的测量表明PDT可以产生严重的肿瘤， 缺氧，但这些方法缺乏空间分辨率来检测梯度， 氧气分布我们假设肿瘤对PDT的反应将是 由氧相对于损伤目标的空间分布确定 (e.g.血管内皮）和光敏剂生物分布。的描述 PDT过程中氧和敏化剂分布的变化可能表明 治疗失败，并促进更有效的治疗方案的发展。 氟化系列2-硝基咪唑缺氧标记物，包括药物 EF 3和EF 5是在我们的实验室内开发的。低血糖标志物是一种 研究PDT对肿瘤氧合的区域效应的独特手段。 EF 3将用于通过以下方式定量鼠肿瘤的氧合： 冷冻切片的免疫组织化学和细胞悬浮液的流式细胞术。 缺氧标志物结合的模式和强度将与缺氧标志物结合的模式和强度进行比较。 光敏剂分布（由其固有荧光确定），肿瘤 血管分布（用抗体标记）、肿瘤灌注（用注射的 荧光染料）和细胞凋亡（通过商业试剂盒检测）。梯度 肿瘤氧合，其可能作为与血液的距离的函数而存在 船舶将被量化。维持氧气供应的后果， 血管的消耗将在PDT相关的 血管损伤，包括坏死和凋亡的发展。的 控制注量率和药物剂量以控制局部氧耗竭 并改善肿瘤反应。将进行调查 使用三种临床相关的光敏剂Photofrin、Foscan和Lutex。

DESCRIPTION: The goals of this project are to quantify oxygen and photosensitizer distributions in tumors, describe the effects of photodynamic therapy (PDT) on these distributions, and measure the consequences on tumor response. Depletion of tumor oxygen by the illuminating light for PDT has been identified as potentially therapy-limiting. Methods of studying this oxygen depletion have included polarographic needle probe measurement of tissue PO(2) and spectroscopic determination of blood oxygen concentration. Tumor-averaged measurements of oxygen concentration indicate that PDT can create severe tumor hypoxia, but these methods lack the spatial resolution to detect gradients in oxygen distribution. We hypothesize that tumor responses to PDT will be determined by the spatial distribution of oxygen relative to targets of damage (e.g. the vascular endothelium) and photosensitizer biodistribution. The description of oxygen and sensitizer distributions during PDT could suggest reasons for treatment failure and facilitate the development of more effective treatment protocols. A fluorinated series of 2-nitroimidazole hypoxic markers, including the drugs EF3 and EF5, has been developed within our laboratories. Hypoxic markers are a unique means to investigate the regional effects of PDT on tumor oxygenation. EF3 will be used to quantify the oxygenation of murine tumors through immunohistochemistry of frozen sections and flow cytometry of cell suspensions. Patterns and intensities of hypoxic marker binding will be compared to those of photosensitizer distribution (determined by their inherent fluorescence), tumor vascularity (labeled by antibodies), tumor perfusion (labeled by injected fluorescent dyes), and apoptosis (detected by commercial kits). Gradients in tumor oxygenation, which may exist as a function of distance from the blood vessels, will be quantified. The consequences of oxygen maintenance or depletion at the blood vessels will be examined in terms of PDT-associated vascular damage, including the development of necrosis and apoptosis. The manipulation of fluence rate and drug dose to control local oxygen depletion and improve tumor response will be examined. Investigations will be carried out using three clinically relevant photosensitizers, Photofrin, Foscan and Lutex.