Intravital microscopy of tumor vessel morphology and function using a standard fluorescence microscope

Abstract

Purpose The purpose of the study was to demonstrate the performance and possible applications of an intravital microscopy assay using a standard fluorescence microscope. Methods Melanoma and pancreatic ductal adenocarcinoma xenografts were initiated in dorsal window chambers and subjected to repeated intravital microscopy. The entire tumor vasculature as well as the normal tissue surrounding the tumor was imaged simultaneously with high spatial and temporal resolution. Vascular morphology images were recorded by using transillumination, and vascular masks were produced to quantify vessel density, vessel diameter, vessel segment length, and vessel tortuosity. First-pass imaging movies were recorded after an intravenous injection of a fluorescent marker and were used to investigate vascular function. Lymphatics were visualized by intradermal injections of a fluorescent marker. Results The intravital microscopy assay was used to study tumor growth and vascularization, tumor vessel morphology and function, tumor-associated lymphatics, and vascular effects of acute cyclic hypoxia and antiangiogenic treatment. The assay was sensitive to tumor-line differences in vascular morphology and function and detected tumor-induced lymphatic dilation. Acute cyclic hypoxia induced angiogenesis and increased the density of small diameter vessels and blood supply times, whereas antiangiogenic treatment selectively removed small-diameter vessels, reduced blood supply times, and induced hypoxia. Moreover, the window chamber was compatible with magnetic resonance imaging (MRI), and parametric images derived by dynamic contrast-enhanced MRI were shown to reflect vascular morphology and function. Conclusions The presented assay represents a useful and affordable alternative to intravital microscopy assays using confocal and multi-photon microscopes.

Applications of Intravital Imaging in Cancer Immunotherapy

“…Peng Si et al describe that label-free optical coherency tomography technology has been applied by advanced novel optical designs and algorithms, enabling optical coherency tomography to detect tumor margins and blood vessels more accurately [ 43 ]. Jon-Vidar Gaustad et al showed that a dorsal window model in mice allowed simultaneous MRI imaging to reflect vascular morphology and function within the tumor microenvironment [ 44 ].…”

Volume imaging to interrogate cancer cell-tumor microenvironment interactions in space and time

“…In a murine model of non-Hodgkin lymphoma, tissue clearing revealed that the delivery of therapeutic CD20 fragment antigen-binding (FAB) antibody regions was dependent on tumor perfusion ( 164 ). IVM showed that preserving endosteal vessels in AML improves the efficacy of chemotherapy ( 123 ).…”

CD133-targeted multifunctional nanomicelles for dual-modality imaging and synergistic high-intensity focus ultrasound (HIFU) ablation on pancreatic cancer in nude mice

“…Currently, DSWC can also be applied to fluorescence and photoacoustic imaging, ultrasound, magnetic resonance imaging (MRI), positron emission tomography (PET) imaging, and multimodal imaging. 27,29,30 Many studies on DSWC have shown the structural and functional differences between tumor blood vessels and normal blood vessels and can quantitatively study tumor blood vessels and normal blood vessel permeability, hemoglobin saturation, and other parameters. In addition, DSWC models enable us to further understand the microcirculation and metabolism of tumors and study living animals at the cellular and molecular levels.…”