A Wireless Laser Speckle and Fluorescence Imager for In vivo Brain Tumor Imaging

描述（由申请人提供）：恶性脑肿瘤的异常血管系统是其灌注、氧合和治疗反应的关键决定因素。因此，评估临床前脑肿瘤模型微血管的早期结构和功能变化可以为指导新疗法的剂量/计划提供宝贵的信息，并为患者提供早期可测量的复发和复发迹象。然而，这需要一种能够在肿瘤的整个生命周期内评估微血管（~10¿m）形态和灌注变化的体内成像技术。激光散斑对比成像（LSCI）是一种满足这些要求的光学成像技术，不需要外源性荧光染料或对比剂的管理。因此，我们建议建立一个最先进的无线头戴式LSCI系统，用于评估微血管结构和灌注的体内变化，并结合荧光模块成像缺氧诱导的绿色荧光蛋白（GFP）在转基因脑肿瘤模型（即9L-HRE-GFP）中的表达。我们希望这种头戴式图像能够量化异常脑肿瘤微血管的生理后果，如肿瘤血流量减少/间歇性减少和缺氧升高。由于某些治疗方法（如抗vegf药物，地塞米松等）已被证明可以使肿瘤血管的结构/功能“正常化”并增强药物输送，我们将测试我们的头戴式成像仪检测这些变化的能力。作为一个测试案例，我们建议描述临床上使用的皮质类固醇地塞米松对9L-HRE-GFP脑肿瘤的“正常化”作用。我们希望LSCI能揭示微血管结构向更“正常”的转变，并伴有灌注改善，荧光成像能揭示在地塞米松“血管正常化”后缺氧的缓解（即诱导型GFP表达的减少）。最后，我们期望本研究提出的多模态（即LSCI和荧光）成像与诱导细胞系（如9L-HRE-GFP）的创新结合能够应用于其他涉及病理性脉管系统的疾病。总的来说，拟议的研究结果将促进对脑肿瘤生物学的基本理解，并为脑肿瘤的临床前测试建立一个新的平台

DESCRIPTION (provided by applicant): The abnormal vasculature of malignant brain tumors is a critical determinant of their perfusion, oxygenation, and response to therapy. Therefore, the assessment of early structural and functional changes in the microvasculature of pre-clinical brain tumor models can provide invaluable information for directing the dosing/scheduling of new therapies and providing early measurable signs of relapse and recurrence in patients. However, this requires an in vivo imaging technique capable of assessing changes in microvascular (~10¿m) morphology and perfusion over the entire life-cycle of a tumor. Laser speckle contrast imaging (LSCI) is an optical imaging technique that meets these requirements and does not require the administration of exogenous fluorescent dyes or contrast agents. Therefore, we are proposing to build a state-of-the-art wireless, head-mounted LSCI system for assessing in vivo changes in microvascular architecture and perfusion combined with a fluorescence module for imaging hypoxia-induced green fluorescent protein (GFP) expression in a transgenic brain tumor model (i.e. 9L-HRE-GFP). We expect this head-mounted image to enable quantification of the physiological consequences of abnormal brain tumor microvasculature, such as decreased/intermittent tumor blood flow and elevated hypoxia. Since certain therapeutics (e.g. anti-VEGF agents, dexamethasone etc.) have been shown to 'normalize' the structure/function of tumor vessels and enhance drug delivery, we will test the ability of our head-mounted imager to detect these changes. As a test case, we propose to characterize the 'normalizing' effects of the clinically used corticosteroid, dexamethasone, on 9L-HRE-GFP brain tumors. We expect LSCI to reveal a shift in the microvasculature towards a more 'normal' architecture accompanied by improved perfusion, and fluorescence imaging to reveal alleviation of hypoxia (i.e. a reduction in inducible GFP expression) following 'vascular normalization' due to dexamethasone. Finally, we expect the innovative combination of multi-modal (i.e. LSCI and fluorescence) imaging and inducible cell lines (e.g. 9L-HRE-GFP) developed in this proposal to be applicable to other diseases involving the pathological vasculature. Collectively, the results of the proposed studies will promote a fundamental understanding of brain tumor biology and establish a novel platform for the pre-clinical testing of new therapies against human brain tumors.