Ethics statement: All experiments were approved by the Institutional Animal Care and Use Committee. Animal care was according to institutional guidelines. ICR female mice (7 - 8 weeks old;&#160;25 - 30 g) were housed in air conditioned, light controlled animal facilities of the Sackler Faculty of Medicine in Tel-Aviv University. At term, animals were euthanized with anesthesia overdose.
1. Fibred Confocal Fluorescence Microscopy (FCFM) Calibration
<ol>
	<li>Turn the device ON.</li>
	<li>Connect the microprobe (mini0/30).</li>
	<li>Calibrate the device according to manufacturer&#8217;s instructions.</li>
</ol>
2. Mice Preparation for Imaging&#160;
<ol>
	<li>Anesthetize&#160;by a subcutaneous injection of both Ketaset (100 mg/kg) and&#160;XYL-M2 (6 mg/kg). Confirm proper anesthetization by unresponsiveness to toe-pinch.</li>
	<li>Incise the skin&#160;below&#160;the&#160;groin&#160;in order to&#160;reveal&#160;the femoral arterial vessels. Keep the incision site moist with saline following incision.</li>
	<li>Heat the tail by using a bag (or a glove) filled with warm water (not too hot to touch) for approximately 30 sec. Prepare an intravenous (IV) shunt for administration of FITC dextran (a contrast agent) and of either saline or chemotherapeutic agent, by inserting a needle (30 G, 1/2 inch) into&#160;the&#160;tail vein and attaching a 1 ml syringe to it. Ensure the vein is open by injecting saline. 
	NOTE: An IV administration of FITC dextran (high molecular weight; 100&#160;&#181;l; 10 mg/ml; 2,000 kDa)&#160;facilitates visualizing the femoral microvasculature by FCFM.&#160;Doxorubicin (100 &#181;l; 8 mg/kg, Adriamycin) or saline&#160;will also be later&#160;administered IV into the pre-heated tail vein.</li>
	<li>Position the mouse supinely on a polystyrene stage. Secure the mouse to the pad and maintain position using surgical duct tape.</li>
</ol>
3. Imaging of Femoral Blood Vessels by FCFM During and After Administration of Doxorubicin&#160;or Saline
NOTE: The fibered confocal microscope used in this study is composed of two units: (1) microprobe (mini0/30). (2) Laser scanning unit (LSU-488; 488 nm wavelength).
<ol>
	<li>Perform all time-laps analyses using the LSU 488 nm wavelength laser.&#160; 
	NOTE: The main unit detector detects the filtered (500 - 650 nm) emitted fluorescence. The acquired images&#160;are&#160;reconstructed afterwards and displayed at&#160;a&#160;rate of 12 frames/sec.</li>
	<li>Disconnect carefully the syringe from the needle and attach a new syringe containing FITC dextran. Administer (IV) 100 &#181;l of FITC dextran.</li>
	<li>Shift&#160;the microprobe (mini0/30) to a suitable field of view and fixate it, following adjustment to the z-axis, in order to obtain the corresponding image. Wait for the initial signal to fade until a clear and focused signal is visible.</li>
	<li>Record a baseline blood flow for a short stabilization period (~30 sec). Then connect to the needle another syringe, containing either doxorubicin or saline. IV administer 100 &#181;l doxorubicin or saline.</li>
	<li>Monitor the flow of injected FITC-dextran continuously for 20 min. On the FCFM-associated software, use the diameter button on the upper ruler in order to measure the blood vessels&#160;and&#160;categorize them as small (&#60;15 &#181;m) or large (&#62;15 &#181;m).</li>
	<li>Euthanize the animal with anesthesia overdose.</li>
</ol>

<ol>
	<li>Chow, A. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anthracyclines+cause+endothelial+injury+in+pediatric+cancer+patients:+a+pilot+study.">Anthracyclines cause endothelial injury in pediatric cancer patients: a pilot study.</a> J Clin Oncol. 24 (6), 925-928 (2006).</li><li>Nuver, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acute+chemotherapy-induced+cardiovascular+changes+in+patients+with+testicular+cancer.">Acute chemotherapy-induced cardiovascular changes in patients with testicular cancer.</a> J Clin Oncol. 23 (36), 9130-9137 (2005).</li><li>Vos, F. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelial+cell+effects+of+cytotoxics:+balance+between+desired+and+unwanted+effects.">Endothelial cell effects of cytotoxics: balance between desired and unwanted effects.</a> Cancer Treat Rev. 30 (6), 495-513 (2004).</li><li>Kerbel, R. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term='Accidental'+anti-angiogenic+drugs.+anti-oncogene+directed+signal+transduction+inhibitors+and+conventional+chemotherapeutic+agents+as+examples.Eur.">'Accidental' anti-angiogenic drugs. anti-oncogene directed signal transduction inhibitors and conventional chemotherapeutic agents as examples.Eur.</a> J Cancer. 36 (10), 1248-1257 (2000).</li><li>Soultati, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelial+vascular+toxicity+from+chemotherapeutic+agents:+preclinical+evidence+and+clinical+implications.">Endothelial vascular toxicity from chemotherapeutic agents: preclinical evidence and clinical implications.</a> Cancer Treat Rev. 38 (5), 473-483 (2012).</li><li>Tempelhoff, G. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blood+coagulation+during+adjuvant+epirubicin/cyclophosphamide+chemotherapy+in+patients+with+primary+operable+breast+cancer.">Blood coagulation during adjuvant epirubicin/cyclophosphamide chemotherapy in patients with primary operable breast cancer.</a> J Clin Oncol. 14 (9), 2560-2568 (1996).</li><li>Ben Aharon, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Doxorubicin-induced+vascular+toxicity--targeting+potential+pathways+may+reduce+procoagulant+activity.">Doxorubicin-induced vascular toxicity--targeting potential pathways may reduce procoagulant activity.</a> PLoS One. 8 (9), e7515 (2013).</li><li>Laemmel, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fibered+confocal+fluorescence+microscopy+(Cell-viZio)+facilitates+extended+imaging+in+the+field+of+microcirculation.+A+comparison+with+intravital+microscopy.">Fibered confocal fluorescence microscopy (Cell-viZio) facilitates extended imaging in the field of microcirculation. A comparison with intravital microscopy.</a> J Vasc Res. 41 (5), 400-411 (2004).</li><li>Al-Gubory, K. H., Houdebine, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+imaging+of+green+fluorescent+protein-expressing+cells+in+transgenic+animals+using+fibred+confocal+fluorescence+microscopy.">In vivo imaging of green fluorescent protein-expressing cells in transgenic animals using fibred confocal fluorescence microscopy.</a> Eur J Cell Biol. 85 (8), 837-845 (2006).</li><li>Bar-Joseph, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+bioimaging+as+a+novel+strategy+to+detect+doxorubicin-induced+damage+to+gonadal+blood+vessels.">In vivo bioimaging as a novel strategy to detect doxorubicin-induced damage to gonadal blood vessels.</a> PLoS One. 6 (9), e23492 (2011).</li><li>Kaushal, V., Kaushal, G. P., Mehta, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+toxicity+of+anthracyclines+on+cultured+endothelial+cells.">Differential toxicity of anthracyclines on cultured endothelial cells.</a> Endothelium. 11 (5-6), 253-258 (2004).</li><li>Kim, E. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Doxorubicin-induced+platelet+cytotoxicity:+a+new+contributory+factor+for+doxorubicin-mediated+thrombocytopenia.">Doxorubicin-induced platelet cytotoxicity: a new contributory factor for doxorubicin-mediated thrombocytopenia.</a> J Thromb Haemost. 7 (7), 1172-1183 (2009).</li><li>Walsh, J., Wheeler, H. R., Geczy, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modulation+of+tissue+factor+on+human+monocytes+by+cisplatin+and+adriamycin.">Modulation of tissue factor on human monocytes by cisplatin and adriamycin.</a> Br J Haematol. 81 (4), 480-488 (1992).</li><li>Kotamraju, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Doxorubicin-induced+apoptosis+in+endothelial+cells+and+cardiomyocytes+is+ameliorated+by+nitrone+spin+traps+and+ebselen.+Role+of+reactive+oxygen+and+nitrogen+species.">Doxorubicin-induced apoptosis in endothelial cells and cardiomyocytes is ameliorated by nitrone spin traps and ebselen. Role of reactive oxygen and nitrogen species.</a> J Biol Chem. 275 (43), 33585-33592 (2000).</li><li>Vasquez-Vivar, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelial+nitric+oxide+synthase-dependent+superoxide+generation+from+adriamycin.">Endothelial nitric oxide synthase-dependent superoxide generation from adriamycin.</a> Biochemistry. 36 (38), 11293-11297 (1997).</li></ol>

Evaluating chemotherapy-induced vascular toxicity is challenging due to the difficulty in visualizing the dynamics of vasculature in response to a stimuli in real-time. Numerous clinical studies have implicated that several chemotherapies cause direct vascular injury, yet the mechanism and characteristics of this toxicity remains to be elucidated. We have established a real-time, in vivo molecular imaging platform for evaluating the potential vascular toxicity of chemotherapy in mice comprising of fibered confoc...

Clinical evidence indicates that several classes of chemotherapies elicit a variety of vascular pathologies manifested by Raynaud phenomenon, hypertension, myocardialinfarction, cerebrovascular attack, and hepatic veno-occlusivedisease1,2. &#8220;&#8217;Accidental&#8217; anti-angiogenic drugs&#8221; is a fairly new term, which describes conventional chemotherapeutic agents that act as possible angiogenesis inhibitors, although they not originally developed for this purpose3-5 but designed to eliminate tumor cells by imposing as little &#8220;collateral damage&#8221; to normal cells as possible3. Several chemotherapies have been implied as vasculo-toxicants as observed in clinical studies using serum biomarkers. Among these are alkylating agents (such as cyclophosphamide), platinum compounds (such as cisplatin) and anthracyclines1,2,5-7.
Acute cardiovascular complications may occur as a result of vascular toxicity induced by chemotherapy. They may progress into chronic conditions like atherosclerosis and account for increased risk of late vascular morbidity. Yet, despite mounting clinical evidence, there is a paucity of designated studies emphasizing the mechanism of vascular toxicity and therefore, further elucidation of the exact pathogenesis they inflict is warranted.
A major challenge in revealing the mechanism of chemotherapy-induced vascular toxicity derives from the complexity of investigating vascular function in vivo. We describe herein a platform of high-resolution in vivo molecular imaging in mice that enables to capture blood flow and vessels&#8217; characteristics. This platform facilitates the detection of direct treatment-induced vascular effects: in real-time, as well as following them over a period of time within the same individuals.

<table><tbody><tr><td>general anesthesia</td><td>Fort Dodge Animal Health, IA, USA and Biove Laboratories, France</td><td></td><td>100 mg/kg ketaset and 6 mg/kg XYL-M2</td></tr><tr><td>depilatory cream (Veet)</td><td>ReckittBenckiser, Bristol, UK</td><td></td><td></td></tr><tr><td>30 G, 1/2 inch needle attached to 1 ml syringe</td><td></td><td></td><td></td></tr><tr><td>FITC dextran (10 mg/ml; MW 2,000 kDa)</td><td>Sigma</td><td>FD2000S</td><td>100 &amp;mu;l volume</td></tr><tr><td>Doxorubicin</td><td>Teva, Israel</td><td></td><td>8 mg/kg, Adriamycin</td></tr><tr><td>paclitaxel</td><td>Taro, Israel</td><td></td><td>1.2 mg/kg, Medexel</td></tr><tr><td>saline</td><td></td><td></td><td></td></tr></tbody></table>

chemotherapy-induced vascular toxicity - real-time in vivo imaging of vessel impairment

Certain classes of chemotherapies may exert acute vascular changes that may progress into long-term conditions that may predispose the patient to an increased risk of vascular morbidity.&#160;Yet, albeit&#160;the mounting clinical evidence, there is a paucity of clear studies of vascular toxicity and therefore the etiology of a heterogeneous group of vascular/cardiovascular disorders remains to be elucidated. Moreover, the mechanism that may underlie vascular toxicity can completely differ from the principles of chemotherapy-induced cardiotoxicity, which is related to direct myocyte injury. We have established a real-time, in vivo molecular imaging platform&#160;to evaluate&#160;the potential&#160;acute&#160;vascular toxicity of anti-cancer therapies.
We have set up a platform of in vivo, high-resolution molecular imaging&#160;in mice,&#160;suitable for visualizing vasculature within confined organs and reference blood vessels within the same individuals whereas each individual serve as its own control. Blood vessel walls were impaired after doxorubicin administration, representing a unique mechanism of vascular toxicity that may be the early event in end-organ injury. Herein, the method of fibered confocal fluorescent microscopy (FCFM) based imaging is described, which provides an innovative mode to understand physiological phenomena at the cellular and sub-cellular levels in animal subjects.

In vivo continuous imaging at real-time
The imaging apparatus used here is a high definition, fibered confocal microscope, equipped with a probe that enables visualization of vasculature and its response to various stimuli as chemotherapy. This method is minimally invasive since although it may facilitate imaging of deep vessels or organ, it requires a small incision for the probe. The probe bundles consist of tens of thousands of fibers, microscope optics and a proprietary precision con...

Watch this Scientific Journal Video about Chemotherapy-induced Vascular Toxicity - Real-time In vivo Imaging of Vessel Impairment at JoVE.com

Chemotherapy-induced Vascular Toxicity - Real-time In vivo Imaging of Vessel Impairment

We herein describe the method of fibered confocal fluorescent microscopy (FCFM) based imaging, which provides an innovative mode to understand physiological phenomena at the cellular and sub-cellular levels in animal subjects.

Chemotherapy-induced Vascular Toxicity - Real-time In vivo Imaging of Vessel Impairment

Certain classes of chemotherapies may exert acute vascular changes that may progress into long-term conditions that may predispose the patient to an ...

chemotherapy-induced-vascular-toxicity-real-time-vivo-imaging-vessel

Research

JoVE Journal

Medicine

7.3K Views.  Tel Aviv University. We herein describe the method of fibered confocal fluorescent microscopy (FCFM) based imaging, which provides an innovative mode to understand physiological phenomena at the cellular and sub-cellular levels in animal subjects.

Video: Chemotherapy-induced Vascular Toxicity - Real-time In vivo Imaging of Vessel Impairment

Evaluation of Nanoparticle Uptake in Tumors in Real Time Using Intravital Imaging

Current technologies for tumor imaging, such as ultrasound, MRI, PET and CT, are unable to yield high-resolution images for the assessment of nanoparticle uptake in tumors at the microscopic level1,2,3, highlighting the utility of a suitable xenograft model in which to perform detailed uptake analyses. Here, we use high-resolution intravital imaging to evaluate nanoparticle uptake in human tumor xenografts in a modified, shell-less chicken embryo model. The chicken embryo model is particularly well-suited for these in vivo analyses because it supports the growth of human tumors, is relatively inexpensive and does not require anesthetization or surgery 4,5. Tumor cells form fully vascularized xenografts within 7 days when implanted into the chorioallantoic membrane (CAM) 6. The resulting tumors are visualized by non-invasive real-time, high-resolution imaging that can be maintained for up to 72 hours with little impact on either the host or tumor systems. Nanoparticles with a wide range of sizes and formulations administered distal to the tumor can be visualized and quantified as they flow through the bloodstream, extravasate from leaky tumor vasculature, and accumulate at the tumor site. We describe here the analysis of nanoparticles derived from Cowpea mosaic virus (CPMV) decorated with near-infrared fluorescent dyes and/or polyethylene glycol polymers (PEG) 7, 8, 9,10,11. Upon intravenous administration, these viral nanoparticles are rapidly internalized by endothelial cells, resulting in global labeling of the vasculature both outside and within the tumor7,12. PEGylation of the viral nanoparticles increases their plasma half-life, extends their time in the circulation, and ultimately enhances their accumulation in tumors via the enhanced permeability and retention (EPR) effect 7, 10,11. The rate and extent of accumulation of nanoparticles in a tumor is measured over time using image analysis software. This technique provides a method to both visualize and quantify nanoparticle dynamics in human tumors.

We present a novel approach to quantify nanoparticle localization in the vasculature of human xenografted tumors using dynamic, real-time intravital imaging in an avian embryo model.

Current technologies for tumor imaging, such as ultrasound, MRI, PET and CT, are unable to yield high-resolution images for the assessment of nanoparticle ...

Live Imaging of Drug Responses in the Tumor Microenvironment in Mouse Models of Breast Cancer

The tumor microenvironment plays a pivotal role in tumor initiation, progression, metastasis, and the response to anti-cancer therapies. Three-dimensional co-culture systems are frequently used to explicate tumor-stroma interactions, including their role in drug responses. However, many of the interactions that occur in vivo in the intact microenvironment cannot be completely replicated in these in vitro settings. Thus, direct visualization of these processes in real-time has become an important tool in understanding tumor responses to therapies and identifying the interactions between cancer cells and the stroma that can influence these responses. Here we provide a method for using spinning disk confocal microscopy of live, anesthetized mice to directly observe drug distribution, cancer cell responses and changes in tumor-stroma interactions following administration of systemic therapy in breast cancer models. We describe procedures for labeling different tumor components, treatment of animals for observing therapeutic responses, and the surgical procedure for exposing tumor tissues for imaging up to 40 hours. The results obtained from this protocol are time-lapse movies, in which such processes as drug infiltration, cancer cell death and stromal cell migration can be evaluated using image analysis software.

We describe a method for imaging response to anti-cancer treatment in vivo and at single cell resolution.

The tumor microenvironment plays a pivotal role in tumor initiation, progression, metastasis, and the response to anti-cancer therapies. Three-dimensional ...

Combined Use of Tail Vein Metastasis Assays and Real-Time In Vivo Imaging to Quantify Breast Cancer Metastatic Colonization and Burden in the Lungs

Metastasis is the main cause of cancer-related deaths and there are limited therapeutic options for patients with metastatic disease. The identification and testing of novel therapeutic targets that will facilitate the development of better treatments for metastatic disease requires preclinical in vivo models. Demonstrated here is a syngeneic mouse model for assaying breast cancer metastatic colonization and subsequent growth. Metastatic cancer cells are stably transduced with viral vectors encoding firefly luciferase and ZsGreen proteins. Candidate genes are then stably manipulated in luciferase/ZsGreen-expressing cancer cells and then the cells are injected into mice via the lateral tail vein to assay metastatic colonization and growth. An in vivo imaging device is then used to measure the bioluminescence or fluorescence of the tumor cells in the living animals to quantify changes in metastatic burden over time. The expression of the fluorescent protein allows the number and size of metastases in the lungs to be quantified at the end of the experiment without the need for sectioning or histological staining. This approach offers a relatively quick and easy way to test the role of candidate genes in metastatic colonization and growth, and provides a great deal more information than traditional tail vein metastasis assays. Using this approach, we show that simultaneous knockdown of Yes associated protein (YAP) and transcriptional co-activator with a PDZ-binding motif (TAZ) in breast cancer cells leads to reduced metastatic burden in the lungs and that this reduced burden is the result of significantly impaired metastatic colonization and reduced growth of metastases.

The described approach combines experimental tail vein metastasis assays with in vivo live animal imaging to allow real-time monitoring of breast cancer metastasis formation and growth in addition to the quantification of metastasis number and size in the lungs.

Metastasis is the main cause of cancer-related deaths and there are limited therapeutic options for patients with metastatic disease. The identification ...

Cancer Research

In vivo Imaging of Tumor Angiogenesis using Fluorescence Confocal Videomicroscopy

Fibered confocal fluorescence in vivo imaging with a fiber optic bundle uses the same principle as fluorescent confocal microscopy. It can excite fluorescent in situ elements through the optical fibers, and then record some of the emitted photons, via the same optical fibers. The light source is a laser that sends the exciting light through an element within the fiber bundle and as it scans over the sample, recreates an image pixel by pixel. As this scan is very fast, by combining it with dedicated image processing software, images in real time with a frequency of 12 frames/sec can be obtained.
We developed a technique to quantitatively characterize capillary morphology and function, using a confocal fluorescence videomicroscopy device. The first step in our experiment was to record 5 sec movies in the four quadrants of the tumor to visualize the capillary network. All movies were processed using software (ImageCell, Mauna Kea Technology, Paris France) that performs an automated segmentation of vessels around a chosen diameter (10 &mu;m in our case). Thus, we could quantify the 'functional capillary density', which is the ratio between the total vessel area and the total area of the image. This parameter was a surrogate marker for microvascular density, usually measured using pathology tools.
The second step was to record movies of the tumor over 20 min to quantify leakage of the macromolecular contrast agent through the capillary wall into the interstitium. By measuring the ratio of signal intensity in the interstitium over that in the vessels, an 'index leakage' was obtained, acting as a surrogate marker for capillary permeability.

In vivo Imaging of Tumor Angiogenesis using Fluorescence Confocal Videomicroscopy

In this paper, we present a method to analyze tumor microvessels in vivo using dynamic contrast-enhanced fluorescence videomicroscopy. Two quantitative parameters were acquired: functional capillary density reflecting the vascularity of the tumor, and index leakage reflecting the leakiness of the endothelial wall.

Fibered confocal fluorescence in vivo imaging with a fiber optic bundle uses the same principle as fluorescent confocal microscopy. It can excite ...

A Novel High-resolution In vivo Imaging Technique to Study the Dynamic Response of Intracranial Structures to Tumor Growth and Therapeutics

We have successfully integrated previously established Intracranial window (ICW) technology 1-4 with intravital 2-photon confocal microscopy to develop a novel platform that allows for direct long-term visualization of tissue structure changes intracranially. Imaging at a single cell resolution in a real-time fashion provides supplementary dynamic information beyond that provided by standard end-point histological analysis, which looks solely at 'snap-shot' cross sections of tissue.
Establishing this intravital imaging technique in fluorescent chimeric mice, we are able to image four fluorescent channels simultaneously. By incorporating fluorescently labeled cells, such as GFP+ bone marrow, it is possible to track the fate of these cells studying their long-term migration, integration and differentiation within tissue. Further integration of a secondary reporter cell, such as an mCherry glioma tumor line, allows for characterization of cell:cell interactions. Structural changes in the tissue microenvironment can be highlighted through the addition of intra-vital dyes and antibodies, for example CD31 tagged antibodies and Dextran molecules.
Moreover, we describe the combination of our ICW imaging model with a small animal micro-irradiator that provides stereotactic irradiation, creating a platform through which the dynamic tissue changes that occur following the administration of ionizing irradiation can be assessed.
Current limitations of our model include penetrance of the microscope, which is limited to a depth of up to 900 &mu;m from the sub cortical surface, limiting imaging to the dorsal axis of the brain. The presence of the skull bone makes the ICW a more challenging technical procedure, compared to the more established and utilized chamber models currently used to study mammary tissue and fat pads 5-7. In addition, the ICW provides many challenges when optimizing the imaging.

A Novel High-resolution In vivo Imaging Technique to Study the Dynamic Response of Intracranial Structures to Tumor Growth and Therapeutics

We describe a novel in vivo imaging technique that couples fluorescent chimeric mice with intracranial windows and high-resolution 2-photon microscopy. This imaging platform aids studies of dynamic changes in brain tissue and microvasculature, at a single-cell level, following pathological insults and is adaptable to assess intracranial drug delivery and distribution.

We have successfully integrated previously established Intracranial window (ICW) technology 1-4 with intravital 2-photon confocal microscopy to develop a ...

In Vivo Imaging to Measure Spontaneous Lung Metastasis of Orthotopically-injected Breast Tumor Cells

Metastasis remains the primary cause of cancer-related death. The succession of events that characterize the metastatic cascade presents multiple opportunities for therapeutic intervention, and the ability to accurately model them in mice is critical to evaluate their effects. Here, a step-by-step protocol is presented for the establishment of orthotopic primary breast tumors and the subsequent monitoring of the establishment and growth of metastatic lesions in the lung using in vivo bioluminescence imaging. This methodology allows for the evaluation of treatment or its biological effects along the entire range of metastatic development, from primary tumor escape to outgrowth in the lungs. Breast orthotopic tumors are generated in mice via injection of a luciferase-labeled cell suspension in the 4th mammary gland. Tumors are allowed to grow and disseminate for a specific amount of time and are then surgically resected. Upon resection, spontaneous lung metastasis is detected, and the growth over time is monitored using in vivo bioluminescence imaging. At the desired experimental endpoint, lung tissue can be collected for downstream analysis. The treatment of established, clinically evident metastasis is critical to improve outcomes for stage IV cancer patients, and it can be evaluated through tail vein models of experimental lung metastasis. However, metastatic dissemination occurs early in breast cancer, and many patients have latent, subclinical disseminated disease after surgery. Utilization of spontaneous models such as this one provides the opportunity to study the whole spectrum of the disease, especially the systemic effects driven by treatment of the primary tumor such as pre-metastatic niche priming, and evaluate treatments on dormant and subclinical disease after surgery.

In Vivo Imaging to Measure Spontaneous Lung Metastasis of Orthotopically-injected Breast Tumor Cells

The manuscript describes a methodology for the establishment as well as longitudinal growth monitoring of spontaneous lung metastasis from orthotopically-injected breast tumors, amenable to intervention at all stages of the metastatic cascade.

Metastasis remains the primary cause of cancer-related death. The succession of events that characterize the metastatic cascade presents multiple ...

Guided Tumor Inoculation and Multimodal Imaging in Mice

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 tumor microenvironment and its response to therapy. These imaging modalities have micron-scale resolution but have limited use in the clinic due to their shallow penetration depth into tissue. More clinically applicable imaging modalities such as CT, MRI, and PET have much greater penetration depth but have comparatively lower spatial resolution (mm scale). 
To translate preclinical intravital imaging findings into the clinic, new methods must be developed to bridge this micro-to-macro resolution gap. Here we describe a dorsal skinfold window chamber tumor mouse model designed to enable preclinical intravital and clinically applicable (CT and MR) imaging in the same animal, and the image analysis platform that links these two disparate visualization methods. Importantly, the described window chamber approach enables the different imaging modalities to be co-registered in 3D using fiducial markers on the window chamber for direct spatial concordance. This model can be used for validation of existing clinical imaging methods, as well as for the development of new ones through direct correlation with "ground truth" high-resolution intravital findings. 
Finally, the tumor response to various treatments-chemotherapy, radiotherapy, photodynamic therapy-can be monitored longitudinally with this methodology using preclinical and clinically applicable imaging modalities. The dorsal skinfold window chamber tumor mouse model and imaging platforms described here can thus be used in a variety of cancer research studies, for example, in translating preclinical intravital microscopy findings to more clinically applicable imaging modalities such as CT or MRI.

Author Spotlight: Integrating High-Resolution Intravital Imaging and MRI to Enhance Stereotactic Body Radiation Therapy Planning

Translation of Intravital microscopy findings is challenged by its shallow depth penetration into tissue. Here we describe a dorsal window chamber mouse model that enables co-registration of intravital microscopy and clinically applicable imaging modalities (e.g., CT, MRI) for direct spatial correlation, potentially streamlining clinical translation of intravital microscopy findings.

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

Extended Time-lapse Intravital Imaging of Real-time Multicellular Dynamics in the Tumor Microenvironment

In the tumor microenvironment, host stromal cells interact with tumor cells to promote tumor progression, angiogenesis, tumor cell dissemination and metastasis. Multicellular interactions in the tumor microenvironment can lead to transient events including directional tumor cell motility and vascular permeability. Quantification of tumor vascular permeability has frequently used end-point experiments to measure extravasation of vascular dyes. However, due to the transient nature of multicellular interactions and vascular permeability, the kinetics of these dynamic events cannot be discerned. By labeling cells and vasculature with injectable dyes or fluorescent proteins, high-resolution time-lapse intravital microscopy has allowed the direct, real-time visualization of transient events in the tumor microenvironment. Here we describe a method for using multiphoton microscopy to perform extended intravital imaging in live mice to directly visualize multicellular dynamics in the tumor microenvironment. This method details cellular labeling strategies, the surgical preparation of a mammary skin flap, the administration of injectable dyes or proteins by tail vein catheter and the acquisition of time-lapse images. The time-lapse sequences obtained from this method facilitate the visualization and quantitation of the kinetics of cellular events of motility and vascular permeability in the tumor microenvironment.

This protocol describes the use of multiphoton microscopy to perform extended time-lapse imaging of multicellular interactions in real time, in vivo at single cell resolution.

In the tumor microenvironment, host stromal cells interact with tumor cells to promote tumor progression, angiogenesis, tumor cell dissemination and ...

Intravital Microscopy of Tumor-associated Vasculature Using Advanced Dorsal Skinfold Window Chambers on Transgenic Fluorescent Mice

Tumor and tumor vessel development, as well as tumor response to therapeutics, are highly dynamic biological processes. Histology provides static information and is often not sufficient for a correct interpretation. Intravital evaluation, in which a process is followed in time, provides extra and often unexpected information. With the creation of transgenic animals expressing cell-specific markers and live cell tracers, improvements to imaging equipment, and the development of several imaging chambers, intravital microscopy has become an important tool to better understand biological processes. This paper describes an experimental design for the investigation of tumor vessel development and of therapeutic effects in a spatial and temporal manner. Using this setup, the stage of vessel development, tip cell and lumen formation, blood flow, extravasation, an established vascular bed, and vascular destruction can be visualized and followed. Furthermore, therapeutic effects, intratumoral fate, and the localization of chemotherapeutic compounds can also be followed.

This protocol describes the intravital imaging of transgenic mice expressing cell-specific fluorescent markers. Intravital imaging provides a non-invasive method for high-resolution observations in living animals using implantable windows through which the microscopic visualization of processes is possible. This method is especially useful to study longitudinal processes.

Tumor and tumor vessel development, as well as tumor response to therapeutics, are highly dynamic biological processes. Histology provides static ...

Using In Vitro Live-cell Imaging to Explore Chemotherapeutics Delivered by Lipid-based Nanoparticles

Conventional imaging techniques can provide detailed information about cellular processes. However, this information is based on static images in an otherwise dynamic system, and successive phases are easily overlooked or misinterpreted. Live-cell imaging and time-lapse microscopy, in which living cells can be followed for hours or even days in a more or less continuous fashion, are therefore very informative. The protocol described here allows for the investigation of the fate of chemotherapeutic nanoparticles after the delivery of doxorubicin (dox) in living cells. Dox is an intercalating agent that must be released from its nanocarrier to become biologically active. In spite of its clinical registration for more than two decades, its uptake, breakdown, and drug release are still not fully understood. This article explores the hypothesis that lipid-based nanoparticles are taken up by the tumor cells and are slowly degraded. Released dox is then translocated to the nucleus. To prevent fixation artifacts, live-cell imaging and time-lapse microscopy, described in this experimental procedure, can be applied.

Using In Vitro Live-cell Imaging to Explore Chemotherapeutics Delivered by Lipid-based Nanoparticles

Live-cell imaging is a powerful tool to visualize dynamic processes. The examination of fixed cells provides only static pictures, which can lead to misinterpretation and confusion about the process. This work presents a method to study uptake, drug release, and intracellular localization of liposomal nanoparticles in living cells.

Conventional imaging techniques can provide detailed information about cellular processes. However, this information is based on static images in an ...

Chemotherapy-induced Vascular Toxicity - Real-time In vivo Imaging of Vessel Impairment

Podsumowanie

Przeglądaj więcej filmów

Rozdziały w tym wideo

Evaluation of Nanoparticle Uptake in Tumors in Real Time Using Intravital Imaging

Live Imaging of Drug Responses in the Tumor Microenvironment in Mouse Models of Breast Cancer

Combined Use of Tail Vein Metastasis Assays and Real-Time In Vivo Imaging to Quantify Breast Cancer Metastatic Colonization and Burden in the Lungs

In vivo Imaging of Tumor Angiogenesis using Fluorescence Confocal Videomicroscopy

A Novel High-resolution In vivo Imaging Technique to Study the Dynamic Response of Intracranial Structures to Tumor Growth and Therapeutics

In Vivo Imaging to Measure Spontaneous Lung Metastasis of Orthotopically-injected Breast Tumor Cells

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

Extended Time-lapse Intravital Imaging of Real-time Multicellular Dynamics in the Tumor Microenvironment

Intravital Microscopy of Tumor-associated Vasculature Using Advanced Dorsal Skinfold Window Chambers on Transgenic Fluorescent Mice

Using In Vitro Live-cell Imaging to Explore Chemotherapeutics Delivered by Lipid-based Nanoparticles