window chamber surgery in tumor cell injected mice for tumor growth visualization and imaging

Inoculación tumoral guiada e imágenes multimodales en ratones

Tumor microvasculature is an important component of the tumor microenvironment that can be a target for therapy and a determinant of treatment response. In the preclinical setting, the microvasculature is typically studied using intravital microscopy in orthotopic or heterotopic window chamber animal models1,2. This has several advantages over histological studies since the imaging is done in live tissues and the tumor can be monitored longitudinally over several weeks or even months2,3. These studies can leverage the high-resolution imaging capabilities of intravital microscopy to study the delivery of therapeutics to the tumor4,5, the causes of treatment resistance6, and the response of the micro vessels to therapies such as antiangiogenic treatment7,8 and radiotherapy2,9.
Intravital microscopy clearly plays an important role in preclinical cancer research; however, how can tumor microenvironmental features be measured in the clinic? Microvascular information would be useful in the clinic for measuring blood supply and tumor cell hypoxia, which is important for determining treatment resistance in radiotherapy10, as well as the ability of the microvasculature to deliver chemotherapeutic agents to the surrounding tumor cells11. For example, in radiotherapy, spatial information on the structure and function of the tumor microvasculature may help personalize a patient&#39;s treatment plan by adjusting the fractionation schedule or by preferentially boosting the dose to avascular and likely hypoxic regions12.
Intravital microscopy can measure these important microvascular features since it has a very high resolution (&#956;m scale); however, its depth penetration into tissue is limited to several hundred microns or a few millimeters, at most making clinical implementation challenging. Indeed, there are some novel applications of intravital microscopy in the clinic13; however, these are still limited to examinations of near-surface level tissue such as the skin14 or mucosal/endothelial linings of various body cavities via flexible catheters/endoscopes15,16.
More commonly, the microvasculature is studied using imaging modalities such as CT17 or MRI18. These clinical imaging modalities can image to any depth within the body, but they have a much lower spatial resolution (mm scale). Thus, there is a need to bridge this resolution gap between preclinical intravital microscopy and clinical imaging modalities to bring high-resolution and detailed microvascular information into the clinic19. Several functional imaging methods have been developed to improve the microvascular imaging capabilities of clinical imaging modalities such as dynamic contrast-enhanced (DCE) MRI and CT20, and Intravoxel incoherent motion (IVIM) MRI21. However, these are model-based methods that provide indirect measurements of the microvasculature and thus, must be validated with appropriate &#34;ground truth&#34; measurements of the microvasculature19,22.
We have developed a dorsal skinfold window chamber (DSFC) tumor mouse model to bridge this gap between preclinical intravital microscopy and clinically applicable imaging modalities such as CT and MRI. The DSFC provides direct access to the tumor for high-resolution, intravital microscopy imaging through a glass window but also clinically applicable imaging such as MRI as it is made of MR-compatible materials (plastic and glass). Furthermore, an included MATLAB code performs multimodality 3D co-registration for direct spatial correlations between preclinical intravital microscopy and clinically applicable imaging modalities. Here we will describe the design and surgery to install the DSFC as well as the procedure to co-register intravital microscopy and clinically applicable imaging modalities.

Autor destacado: Integración de imágenes intravitales de alta resolución y resonancia magnética para mejorar la planificación de la radioterapia corporal estereotáctica

Un modelo de ratón tumoral con cámara de ventana de pliegue cutáneo dorsal para la microscopía intravital combinada y la resonancia magnética en la investigación traslacional del cáncer

Preclinical intravital imaging has very high resolution, but limited depth penetration in the tissue, which makes it very good for preclinical imaging studies. On the other hand, MRI is much more clinically applicable and has a higher depth penetration, but very low spatial resolution. The goal of this study is to correlate these two modalities with each other in order to better translate our findings from preclinical intravital microscopy into the clinic via magnetic resonance imaging.Perfusion-sensitive imaging methods in MRI and biophotonics, including our optical coherence tomography and geography system, are revealing how the microvasculature impacts tumor response to hypofractionated radiotherapy. 3D printing is also aiding through cost-effective custom tool manufacturing, facilitating longitudinal studies. Finally, AI image analysis is facilitating the identification of novel radiotherapy predictive biomarkers.We've made several findings concerning the tumor response to hypofractionated radiotherapy, including more recently, the temporal kinetics of both radiobiologically significant and abstracted AI-derived tissue response metrics. Additionally, we have demonstrated the promise for multimodal imaging being performed more accurately, correlating both MRI, macroscopic and optical coherence tomography, microscopic, angiography-derived metrics. By extending the effective length of longitudinal studies, we may better identify predictive biomarkers for long-term tumor treatment response.Additionally, by improving robustness of co-registration between macroscopic clinically available imaging modalities and microscopic preclinical imaging modalities, we may enhance the translatability of our findings from benchtop to bedside. During a stereotactic body radiation therapy, high doses of radiation are delivering a reduced number of fractions. One potential radiobiological target associated with increased cell death in SVRT is the tumor microvasculature.By combining high-resolution optical angiography and MRI, we want to enable functional MRI microvascular imaging for patient-specific SVRT treatment planning and improved outcomes.

Cirugía de cámara de ventana en ratones inyectados con células tumorales para la visualización e imagen del crecimiento tumoral

Para comenzar, esterilice las partes de la cámara de la ventana principal en un desinfectante líquido de alto nivel durante 12 minutos. A continuación, se sumerge en alcohol isopropílico durante cinco minutos. Administre un miligramo por kilogramo de buprenorfina de liberación sostenida al ratón inyectado con células tumorales de una a tres horas antes de la cirugía.Para la desinfección, frote el ratón anestesiado y afeitado con una solución de povidona yodada al 7,5%. Limpie el exfoliante desinfectante con alcohol isopropílico al 70%. Aplique una solución de povidona yodada al 10% sobre la piel.Por último, aplica un lubricante ocular veterinario para evitar la sequedad. Levanta la piel del ratón a lo largo de la columna vertebral y localiza el tumor que crece en uno de los pliegues cutáneos laterales. Coloque el marco posterior de la cámara de la ventana del pliegue cutáneo dorsal, o DSFC, de modo que el tumor esté centrado dentro del marco.Agregue tres suturas en los tres orificios superiores de la DSFC y la guía quirúrgica para fijar la posición del marco de la espalda. Inserte tres agujas a través del marco trasero de la DSFC en los orificios que contienen los espaciadores. Con un marcador quirúrgico, marque tres puntos para los espaciadores del marco trasero DSFC en la piel.Dibuja un círculo de un centímetro de diámetro para indicar el área de la piel que se va a eliminar. Después de marcar tres puntos adicionales, corte las suturas para quitar las agujas y el marco posterior. Retire la piel del círculo marcado con las microtijeras quirúrgicas.A continuación, coloque la sutura temporal para asegurar las piezas de la cámara de la ventana a la piel. Apriete el conjunto con una sutura temporal e inserte el marco delantero debajo de la piel a través del orificio. Coloque suturas permanentes a través de los orificios alrededor del perímetro de los marcos delantero y trasero de la DSFC.Después de quitar la sutura temporal, fije el clip de soporte al marco trasero de la DSFC. Administre cinco miligramos de meloxicam por kilogramo de peso corporal por vía subcutánea al ratón para reducir el dolor y la inflamación.

window-chamber-surgery-tumor-cell-injected-mice-for-tumor-growth

Research

JoVE Journal

Cancer Research

Window Chamber Surgery in Tumor Cell Injected Mice for Tumor Growth Visualization and Imaging

A Dorsal Skinfold Window Chamber Tumor Mouse Model for Combined Intravital Microscopy and Magnetic Resonance Imaging in Translational Cancer Research

Preclinical intravital imaging such as microscopy and optical coherence tomography have proven to be valuable tools in cancer research for visualizing the ...

Investigación

Investigación sobre el cáncer

Tumor Cells Inoculation in Mice Through Precise Landmarking and Injection Techniques

Inoculación de células tumorales en ratones mediante técnicas precisas de localización e inyección

Integrative Imaging Techniques for Tumor Analysis in Mice

Técnicas de imagen integrativa para el análisis de tumores en ratones