Structural and Functional Optical Imaging of Angiogenesis in Animal Models

Publisher Summary This chapter describes the structural and functional optical imaging of angiogenesis in animal models. Two animal models for microscopic optical imaging of angiogenesis are presented. Imaging studies have identified multiple cellular and molecular abnormalities that distinguish tumor vessels from their normal vessels and help explain their unusual appearance, irregular blood flow, and vascular leakiness. Most tumor vessels display a disorganized pattern and do not fit into the conventional hierarchy of arterioles, capillaries, and venules. The microphotographs of live tumors in the window chamber are used to obtain measurements of tumor vascular length density as an indicator of tumor vasculature. Vascularized tumors developed in 1 week, at the time they were treated with local irradiation. Irradiation treatment induced a dose- and time-dependent destruction to tumor blood vessels within the window. Radiation-sensitive tumor vessels in melanoma B16F0 showed a rapid and marked regression following 3 Gy of irradiation. It is suggested that optical imaging not only provides powerful tools with which to study the molecular mechanisms of tumor angiogenesis, identify therapeutic targets, and validate the targets in animal models, but it will also be a valuable measurement for monitoring drug response in patients.