Longitudinal imaging is used in pre-clinical studies to follow the progress of a disease or measure the effect of a therapeutic. In oncology, optical methods provide rigorous tools to monitor tumor growth and deliver precise quantitation of cell growth or gene expression at each time point in such a study. Anatomical changes can be measured using a high resolution technique like microCT, but for longitudinal imaging a low X-ray dose must be used to avoid biological artifacts. Optical and microCT images can be co-registered to provide a combination of functional and anatomical data ensuring that maximum information is extracted from the animal model.
1. Cell preparation
<ol>
<li>Caliper provides a range of luciferase expressing cancer cell lines for pre-clinical research in mouse models.</li>
<li>MDA-MB-231-luc-D2H2LN is a human mammary tumor cell line expressing the luciferase gene which can be used as an optical indicator of tumorgenesis in vivo. This cell line is created from a spontaneous lymph node metastasis that originated from a D3H1 mammary fat pad tumor and is known to aggressively form metastases.</li>
<li>The cells are provided as a pathogen-free frozen culture which readily grows in standard media with no need for selection markers.</li>
<li>To verify Luciferase activity before injection into the animal a 90% confluent flask is harvested by trypsinization. Luciferase activity is measured by dispensing 50,000 cells in a microtiter plate and performing serial dilution.</li>
</ol>
2. Intracardiac injection of cells in animals
<ol>
<li>Before injection, animals are anesthetized using 3% isoflurane.</li>
<li>1-3 million cells are injected in 50ul volume in to the left ventricle. Cell suspension contains 150ug/ml D-Luciferin to validate injection technique.</li>
<li>To confirm a correct intracardiac injection mice are imaged in the IVIS system. Mice that show BLI signal throughout the body have been injected correctly. If signal is localized the cells were not injected correctly in the heart.</li>
</ol>
3. BLI imaging to monitor metastases
<ol>
<li>The imaging shuttle supports the mouse for data capture in both IVIS Spectrum and the QuantumFX microCT system.</li>
<li>The shuttle helps maintain the animal in the same position for imaging and incorporates fiducial signals to aid in automatic co-registration. The chamber is connected to the isofluorance vaporizer to maintain anesthesia.</li>
<li>Imaging wizard in the Living Image software 4.1 can be used to automatically select the exposure time, f-stop and binning and ensure quantitative data collection.</li>
<li>Multiple images can be acquired and compared in longitudinal studies covering seconds or months depending on the nature of the experiment.</li>
<li>Day 6 post injection of cells, BLI imaging with IVIS Spectrum shows metastases to the bone in seven out of nine mice.</li>
</ol>
4. Longitudinal monitoring of osteolytic lesions using micro CT
<ol>
<li>Mice that showed clear bone metastases visible using BLI were imaged in the Quantum FX micro CT system.</li>
<li>The Quantum FX micro CT system delivers high quality images at an X-ray dose low enough to enable true longitudinal micro CT in preclinical studies.</li>
<li>Bone degradation in both legs can be longitudinally monitored using this system in less than a minute.</li>
<li>Mice are anesthetized with 3% isoflurane and can be transferred directly from the IVIS Spectrum system.</li>
<li>Two 60mm images are stitched together to capture the whole animal view.</li>
<li>A 30mm FOV is ideal for imaging the knee joint in high resolution.</li>
<li>A single scan with high enough resolution to measure and quantify bone metastases takes just 18 seconds and delivers a dose of only 13mGy.</li>
<li>Mice were imaged up to 8 times in 36 days with the micro CT system without affecting the tumor growth or health of the animal.</li>
<li>The micro CT imaging showed that bone leisions were visible on Day 10 and progressed very rapidly, corresponding to the increase in BLI signal.</li>
</ol>
5. 3D co-registration and analysis of BLI and uCT
<ol>
<li>Once images have been captured on both the IVIS spectrum and Quantum FX micro CT system data can be co-registered into a 3D reconstruction.</li>
<li>MicroCT images are exported as DICOM files and loaded into the Living Image 4.1 3D Multi modality tool.</li>
<li>In the Living Image Software run the DLIT program to three dimensionally reconstruct the optical signal.</li>
<li>The fiducial tool in the software is used to co-register the optical BLI signal to the micro CT image.</li>
<li>Coregistered data sets can be analyzed quantitatively to monitor multiple parameters during disease progression here we are tracking growth of the metastatic tumor together with development of the osteolytic lesion in the bone.</li>
</ol>

<ol>
	<li>Jenkins, D. E., Hornig, Y. S., Oei, Y., Dusich, J., Purchio, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioluminescent+Human+Breast+Cancer+Cell+Lines+that+Permit+Rapid+and+Sensitive+in+vivo+Detection+of+Mammary+Tumors+and+Multiple+Metastases+in+Immune+Deficient+Mice.">Bioluminescent Human Breast Cancer Cell Lines that Permit Rapid and Sensitive in vivo Detection of Mammary Tumors and Multiple Metastases in Immune Deficient Mice.</a> Breast Cancer Research. 7, R444-R454 (2005).</li><li>Cowey, S., Szafran, A. A., Kappes, J., Zinn, K. R., Siegal, G. P., Desmond, R. A., Kim, H., Evans, L., Hardy, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Breast+Cancer+Metastasis+to+Bone:+Evaluation+of+Bioluminescent+Imaging+and+MicroSPECT/CT+for+Detecting+Bone+Metastasis+in+Immunodeficient+Mice.">Breast Cancer Metastasis to Bone: Evaluation of Bioluminescent Imaging and MicroSPECT/CT for Detecting Bone Metastasis in Immunodeficient Mice.</a> Clinical and Experimental Metastasis. 24, 389-401 (2007).</li><li>Labrinidis, A., Hay, S., Liapis, V., Ponomarev, V., Findlay, D. M., Evdokiou, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zoledronic+Acid+Inhibits+Both+the+Osteolytic+and+Osteoblastic+Components+of+Osteosarcoma+Lesions+in+a+Mouse+Model.">Zoledronic Acid Inhibits Both the Osteolytic and Osteoblastic Components of Osteosarcoma Lesions in a Mouse Model.</a> Clinical Cancer Research. 15, (2009).</li><li>Kaijzel, E. L., Pluijm, G. v. a. n. d. e. r., Lowik, C. W. G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Whole-Body+Optical+Imaging+in+Animal+Models+to+Assess+Cancer+Development+and+Progression.">Whole-Body Optical Imaging in Animal Models to Assess Cancer Development and Progression.</a> Clinical Cancer Research. 13, 3490-3497 (2007).</li><li>Minn, A. J., Kang, Y., Serganova, I., Gupta, G. P., Giri, D. D., Doubrovin, M., Ponomarev, V., Gerald, W. L., Blasberg, R., Massague, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distinct+Organ-Specific+Metastatic+Potential+of+Individual+Breast+Cancer+Cells+and+Primary+Tumors.">Distinct Organ-Specific Metastatic Potential of Individual Breast Cancer Cells and Primary Tumors.</a> The Journal of Clinical Investigation. 115, (2005).</li><li>Xu, H., Christensen, A., Kuo, C., Nilson, D., Lim, E., Whalen, J., Kim, J. B., Zhang, N., Singh, R., Oldfield, S., Troy, T., Rice, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Co-registration+of+in+vivo+Optical+Tomography+and+Micro-CT+for+Longitudinal+Studies.">Co-registration of in vivo Optical Tomography and Micro-CT for Longitudinal Studies.</a> Word Molecular Imaging Congress. , (2010).</li></ol>

The authors are employees of Caliper Life Sciences who make the instrument featured in this article.

Small animal imaging with microCT has been applied to monitoring osteolytic lesions under pathological conditions, such as tumor development (Cowey et al. 2007; Labrinidis et al., 2009). As bioluminescence imaging of luciferase labeled tumors has been widely adopted pre-clinically, co-registration of bioluminescence and microCT images provided a better definition of anatomical location of the bioluminescence signals (Kaijzel et al. 2007). Previous study with a luciferase labeled breast tumor cell line MDA-MB-231-luc-D3H2LN showed metastases to bone and development of osteolytic lesions following intra-cardiac injection (Jenkins et al 2005; Minn et al., 2005). In this study, we explored a longitudinal study of tumor metastases and osteolytic activity with combinatory optical and low-radiation-dose microCT imaging with the systemic MDA-MB-231-luc-D3H2LN metastasis model. We performed sequential imaging with IVIS Spectrum and Quantum FX microCT systems and achieved bioluminescence and CT co-registration with our newly developed Living Image 4.1 software (Heng et al., 2010). Bioluminescence imaging with IVIS provides non-invasive detection of the tumor cells with high sensitivity, allowing the tumors to be detected at early stage. Imaging with Quantum FX allows accurate 3D reconstruction of the bone lesions and detailed anatomical information. Quantum FX system offers low radiation dose imaging, which enables longitudinal monitoring of disease progression. Correlation of bone lesions and tumor metastases was depicted in the co-registered image, and the advantage of multimodality tracking of lesion development longitudinally was clearly demonstrated.

monitoring tumor metastases and osteolytic lesions with bioluminescence and micro ct imaging

Following intracardiac delivery of MDA-MB-231-luc-D3H2LN cells to Nu/Nu mice, systemic metastases developed in the injected animals. Bioluminescence imaging using IVIS Spectrum was employed to monitor the distribution and development of the tumor cells following the delivery procedure including DLIT reconstruction to measure the tumor signal and its location.
Development of metastatic lesions to the bone tissues triggers osteolytic activity and lesions to tibia and femur were evaluated longitudinally using micro CT. Imaging was performed using a Quantum FX micro CT system with fast imaging and low X-ray dose. The low radiation dose allows multiple imaging sessions to be performed with a cumulative X-ray dosage far below LD50. A mouse imaging shuttle device was used to sequentially image the mice with both IVIS Spectrum and Quantum FX achieving accurate animal positioning in both the bioluminescence and CT images. The optical and CT data sets were co-registered in 3-dimentions using the Living Image 4.1 software. This multi-mode approach allows close monitoring of tumor growth and development simultaneously with osteolytic activity.

Watch this Scientific Journal Video about Monitoring Tumor Metastases and Osteolytic Lesions with Bioluminescence and Micro CT Imaging at JoVE.com

Monitoring Tumor Metastases and Osteolytic Lesions with Bioluminescence and Micro CT Imaging

An experimental mouse model of bone metastasis was established following intracardiac delivery of luciferase expressing mammary tumor cells. Tumor development and resulted osteolytic lesion were monitored longitudinally with bioluminescence and micro CT imaging.

Following intracardiac delivery of MDA-MB-231-luc-D3H2LN cells to Nu/Nu mice, systemic metastases developed in the injected animals. Bioluminescence ...

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Video: Monitoring Tumor Metastases and Osteolytic Lesions with Bioluminescence and Micro CT Imaging

In vivo Bioluminescence Imaging of Tumor Hypoxia Dynamics of Breast Cancer Brain Metastasis in a Mouse Model

It is well recognized that tumor hypoxia plays an important role in promoting malignant progression and affecting therapeutic response negatively. There is little knowledge about in situ, in vivo, tumor hypoxia during intracranial development of malignant brain tumors because of lack of efficient means to monitor it in these deep-seated orthotopic tumors. Bioluminescence imaging (BLI), based on the detection of light emitted by living cells expressing a luciferase gene, has been rapidly adopted for cancer research, in particular, to evaluate tumor growth or tumor size changes in response to treatment in preclinical animal studies. Moreover, by expressing a reporter gene under the control of a promoter sequence, the specific gene expression can be monitored non-invasively by BLI. Under hypoxic stress, signaling responses are mediated mainly via the hypoxia inducible factor-1&alpha; (HIF-1&alpha;) to drive transcription of various genes. Therefore, we have used a HIF-1&alpha; reporter construct, 5HRE-ODD-luc, stably transfected into human breast cancer MDA-MB231 cells (MDA-MB231/5HRE-ODD-luc). In vitro HIF-1&alpha; bioluminescence assay is performed by incubating the transfected cells in a hypoxic chamber (0.1% O2) for 24 hr before BLI, while the cells in normoxia (21% O2) serve as a control. Significantly higher photon flux observed for the cells under hypoxia suggests an increased HIF-1&alpha; binding to its promoter (HRE elements), as compared to those in normoxia. Cells are injected directly into the mouse brain to establish a breast cancer brain metastasis model. In vivo bioluminescence imaging of tumor hypoxia dynamics is initiated 2 wks after implantation and repeated once a week. BLI reveals increasing light signals from the brain as the tumor progresses, indicating increased intracranial tumor hypoxia. Histological and immunohistochemical studies are used to confirm the in vivo imaging results. Here, we will introduce approaches of in vitro HIF-1&alpha; bioluminescence assay, surgical establishment of a breast cancer brain metastasis in a nude mouse and application of in vivo bioluminescence imaging to monitor intracranial tumor hypoxia.

In vivo Bioluminescence Imaging of Tumor Hypoxia Dynamics of Breast Cancer Brain Metastasis in a Mouse Model

Bioluminescence imaging of hypoxia inducible factor-1&alpha; activity is applied to monitor intracranial tumor hypoxia development in a breast cancer brain metastasis mouse model.

It is well recognized that tumor hypoxia plays an important role in promoting malignant progression and affecting therapeutic response negatively. There ...

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 ...

Osmotic Drug Delivery to Ischemic Hindlimbs and Perfusion of Vasculature with Microfil for Micro-Computed Tomography Imaging

Preclinical research in animal models of peripheral arterial disease plays a vital role in testing the efficacy of therapeutic agents designed to stimulate microcirculation. The choice of delivery method for these agents is important because the route of administration profoundly affects the bioactivity and efficacy of these agents1,2. In this article, we demonstrate how to locally administer a substance in ischemic hindlimbs by using a catheterized osmotic pump. This pump can deliver a fixed volume of aqueous solution continuously for an allotted period of time. We also present our mouse model of unilateral hindlimb ischemia induced by ligation of the common femoral artery proximal to the origin of profunda femoris and epigastrica arteries in the left hindlimb. Lastly, we describe the in vivo cannulation and ligation of the infrarenal abdominal aorta and perfusion of the hindlimb vasculature with Microfil, a silicone radiopaque casting agent. Microfil can perfuse and fill the entire vascular bed (arterial and venous), and because we have ligated the major vascular conduit for exit, the agent can be retained in the vasculature for future ex vivo imaging with the use of small specimen micro-CT3.

We show here the in vivo insertion of an osmotic pump for constant local drug delivery and the creation of hindlimb ischemia in a mouse model. Moreover, the hindlimb vasculature is perfused with Microfil, a silicone radiopaque agent, to prepare for micro-computed tomography (micro-CT) imaging.

Preclinical research in animal models of peripheral arterial disease plays a vital role in testing the efficacy of therapeutic agents designed to ...

Bioluminescence Imaging of an Immunocompetent Animal Model for Glioblastoma

In contrast to commonly reported human glioma xenograft animal models, GL261 murine glioma xenografts recapitulate nearly all relevant clinical and histopathologic features of the human disease. When GL261 cells are implanted intracranially in syngeneic C57BL/6 mice, the model has the added advantage of maintaining an intact immune microenvironment. Stable expression of luciferase in GL261 cells allows non-invasive cost effective bioluminescence monitoring of intracranial tumor growth. We have recently demonstrated that luciferase expression in GL261 cells does not affect the tumor growth properties, tumor cell immunomodulatory cytokine expression, infiltration of immune cells into the tumor, or overall survival of animals bearing the intracranial tumor. Therefore, it appears that the GL261 luciferase glioma model can be useful in the study of novel chemotherapeutic and immunotherapeutic modalities. Here we report the technique for generating stable luciferase expression in GL261 cells and how to study the in vitro and in vivo growth of the tumor cells by bioluminescence imaging.

GL261 glioma cells provide a useful immunocompetent animal model of glioblastoma. The goals of this protocol are to demonstrate proper techniques for monitoring intracranial tumor growth using in vivo bioluminescence imaging, and to verify the utility of luciferase-modified GL261 cells for studying tumor immunology and immunotherapeutic approaches for treating glioblastoma.

In contrast to commonly reported human glioma xenograft animal models, GL261 murine glioma xenografts recapitulate nearly all relevant clinical and ...

Bioluminescence-Based Tumor Quantification Method for Monitoring Tumor Progression and Treatment Effects in Mouse Lymphoma Models

Although bioluminescence imaging (BLI) shows promise for monitoring tumor burden in animal models of cancer, these analyses remain mostly qualitative. Here we describe a method for bioluminescence imaging to obtain a semi-quantitative analysis of tumor burden and treatment response. This method is based on the calculation of a luminoscore, a value that allows comparisons of two animals from the same or different experiments. Current BLI instruments enable the calculation of this luminoscore, which relies mainly on the acquisition conditions (back and front acquisitions) and the drawing of the region of interest (manual markup around the mouse). Using two previously described mouse lymphoma models based on cell engraftment, we show that the luminoscore method can serve as a noninvasive way to verify successful tumor cell inoculation, monitor tumor burden, and evaluate the effects of in situ cancer treatment (CpG-DNA). Finally, we show that this method suits different experimental designs. We suggest that this method be used for early estimates of treatment response in preclinical small-animal studies.

Bioluminescence imaging is a well-known tool for localizing tumors and metastases, but quantification of these images often requires complex calculations and particular instruments. We describe the easy-to-use luminoscore method, based on precise acquisition conditions, requiring no calculations, and enabling tumor burden and treatment response to be monitored in mouse models.

Although bioluminescence imaging (BLI) shows promise for monitoring tumor burden in animal models of cancer, these analyses remain mostly qualitative. ...

Combined Near-infrared Fluorescent Imaging and Micro-computed Tomography for Directly Visualizing Cerebral Thromboemboli

Direct thrombus imaging visualizes the root cause of thromboembolic infarction. Being able to image thrombus directly allows far better investigation of stroke than relying on indirect measurements, and will be a potent and robust vascular research tool. We use an optical imaging approach that labels thrombi with a molecular imaging thrombus marker&#160;&#8212; a Cy5.5 near-infrared fluorescent (NIRF) probe that is covalently linked to the fibrin strands of the thrombus by the fibrin-crosslinking enzymatic action of activated coagulation factor XIIIa during the process of clot maturation. A micro-computed tomography (microCT)-based approach uses thrombus-seeking gold nanoparticles (AuNPs) functionalized to target the major component of the clot: fibrin. This paper describes a detailed protocol for the combined in vivo microCT and ex vivo NIRF imaging of thromboemboli in a mouse model of embolic stroke. We show that in vivo microCT and fibrin-targeted glycol-chitosan AuNPs (fib-GC-AuNPs) can be used for visualizing both in situ thrombi and cerebral embolic thrombi. We also describe the use of in vivo microCT-based direct thrombus imaging to serially monitor the therapeutic effects of tissue plasminogen activator-mediated thrombolysis. After the last imaging session, we demonstrate by ex vivo NIRF imaging the extent and the distribution of residual thromboemboli in the brain. Finally, we describe quantitative image analyses of microCT and NIRF imaging data. The combined technique of direct thrombus imaging allows two independent methods of thrombus visualization to be compared: the area of thrombus-related fluorescent signal on ex vivo NIRF imaging vs. the volume of hyperdense microCT thrombi in vivo.

This protocol describes the application of combined near-infrared fluorescent (NIRF) imaging and micro-computed tomography (microCT) for visualizing cerebral thromboemboli. This technique allows the quantification of thrombus burden and evolution. The NIRF imaging technique visualizes fluorescently labeled thrombus in excised brain, while the microCT technique visualizes thrombus inside living animals using gold-nanoparticles.

Direct thrombus imaging visualizes the root cause of thromboembolic infarction. Being able to image thrombus directly allows far better investigation of ...

Determining Glucose Metabolism Kinetics Using 18F-FDG Micro-PET/CT

This paper describes the use of 18F-FDG and micro-PET/CT imaging to determine in vivo glucose metabolism kinetics in mice (and is transferable to rats). Impaired uptake and metabolism of glucose in multiple organ systems due to insulin resistance is a hallmark of type 2 diabetes. The ability of this technique to extract an image-derived input function from the vena cava using an iterative deconvolution method eliminates the requirement of the collection of arterial blood samples. Fitting of tissue and vena cava time activity curves to a two-tissue, three compartment model permits the estimation of kinetic micro-parameters related to the 18F-FDG uptake from the plasma to the intracellular space, the rate of transport from intracellular space to plasma and the rate of 18F-FDG phosphorylation. This methodology allows for multiple measures of glucose uptake and metabolism kinetics in the context of longitudinal studies and also provides insights into the efficacy of therapeutic interventions.

Determining Glucose Metabolism Kinetics Using 18F-FDG Micro-PET/CT

This study describes a protocol that uses 18F-FDG and positron emission tomography/computed tomography (PET/CT) imaging, together with kinetic modelling, to quantify the in vivo, real-time uptake of 18F-FDG into tissues.

This paper describes the use of 18F-FDG and micro-PET/CT imaging to determine in vivo glucose metabolism kinetics in mice (and is transferable to rats). ...

Bioluminescence and Near-infrared Imaging of Optic Neuritis and Brain Inflammation in the EAE Model of Multiple Sclerosis in Mice

Experimental autoimmune encephalomyelitis (EAE) in SJL/J mice is a model for relapsing-remitting multiple sclerosis (RRMS). Clinical EAE scores describing motor function deficits are basic readouts of the immune-mediated inflammation of the spinal cord. However, scores and body weight do not allow for an in vivo assessment of brain inflammation and optic neuritis. The latter is an early and frequent manifestation in about 2/3 of MS patients. Here, we show methods for bioluminescence and near-infrared live imaging to assess EAE evoked optic neuritis, brain inflammation, and blood-brain barrier (BBB) disruption in living mice using an in vivo imaging system. A bioluminescent substrate activated by oxidases primarily showed optic neuritis. The signal was specific and allowed the visualization of medication effects and disease time courses, which paralleled the clinical scores. Pegylated fluorescent nanoparticles that remained within the vasculature for extended periods of time were used to assess the BBB integrity. Near-infrared imaging revealed a BBB leak at the peak of the disease. The signal was the strongest around the eyes. A near-infrared substrate for matrix metalloproteinases was used to assess EAE-evoked inflammation. Auto-fluorescence interfered with the signal, requiring spectral unmixing for quantification. Overall, bioluminescence imaging was a reliable method to assess EAE-associated optic neuritis and medication effects and was superior to the near-infrared techniques in terms of signal specificity, robustness, ease of quantification, and cost.

We show a technique for in vivo live bioluminescence and near-infrared imaging of optic neuritis and encephalitis in the experimental autoimmune encephalomyelitis (EAE) model for multiple sclerosis in SJL/J mice.

Experimental autoimmune encephalomyelitis (EAE) in SJL/J mice is a model for relapsing-remitting multiple sclerosis (RRMS). Clinical EAE scores describing ...

Induction and Micro-CT Imaging of Cerebral Cavernous Malformations in Mouse Model

Mutations in the CCM1 (aka KRIT1), CCM2, or CCM3 (aka PDCD10) gene cause cerebral cavernous malformation (CCM) in humans. Mouse models of CCM disease have been established by tamoxifen induced deletion of Ccm genes in postnatal animals. These mouse models provide invaluable tools to investigate molecular mechanism and therapeutic approaches for CCM disease. An accurate and quantitative method to assess lesion burden and progression is essential to harness the full value of these animal models. Here, we demonstrate the induction of CCM disease in a mouse model and the use of the contrast enhanced X-ray micro computed tomography (micro-CT) method to measure CCM lesion burden in mouse brains. At postnatal day 1 (P1), we used 4-hydroxytamoxifen (4HT) to activate Cre recombinase activity from the Cdh5-CreErt2 transgene to cleave the floxed allele of Ccm2. CCM lesions in mouse brains were analyzed at P8. For micro-CT, iodine based Lugol&#39;s solution was used to enhance contrast in brain tissue. We have optimized the scan parameters and utilized a voxel dimension of 9.5 &#181;m, which lead to a minimum feature size of approximately 25 &#181;m. This resolution is sufficient to measure CCM lesion volume and number globally and accurately, and provide high-quality 3-D mapping of CCM lesions in mouse brains. This method enhances the value of the established mouse models to study the molecular basis and potential therapies for CCM and other cerebrovascular diseases.

This protocol demonstrates the induction of cerebral cavernous malformation disease in a mouse model and uses contrast enhanced micro computed tomography to measure lesion burden. This method enhances the value of established mouse models to study the molecular basis and potential therapies for cerebral cavernous malformation and other cerebrovascular diseases.

Mutations in the CCM1 (aka KRIT1), CCM2, or CCM3 (aka PDCD10) gene cause cerebral cavernous malformation (CCM) in humans. Mouse models of CCM disease have ...

Gene Regulation and Targeted Therapy in Gastric Cancer Peritoneal Metastasis: Radiological Findings from Dual Energy CT and PET/CT

Gastric cancer remains fourth in cancer incidence worldwide with a five-year survival of only 20%-30%. Peritoneal metastasis is the most frequent type of metastasis that accompanies unresectable gastric cancer and is a definitive determinant of prognosis. Preventing and controlling the development of peritoneal metastasis could play a role in helping to prolong the survival of gastric cancer patients. A non-invasive and efficient imaging technique will help us to identify the invasion and metastasis process of peritoneal metastasis and to monitor the changes in tumor nodules in response to treatments. This will enable us to obtain an accurate description of the development process and molecular mechanisms of gastric cancer. We have recently described experiment using dual energy CT (DECT) and positron emission tomography/computed tomography (PET/CT) platforms for the detection and monitoring of gastric tumor metastasis in nude mice models. We have shown that weekly continuous monitoring with DECT and PET/CT can identify dynamic changes in peritoneal metastasis. The sFRP1-overexpression in gastric cancer mice models showed positive radiological performance, a higher FDG uptake and increasing enhancement, and the SUVmax (standardized uptake value) of nodules demonstrated an obvious alteration trend in response to targeted therapy of TGF-&#946;1 inhibitor. In this article, we described the detailed non-invasive imaging procedures to conduct more complex research on gastric cancer peritoneal metastasis using animal models and provided representative imaging results. The use of non-invasive imaging techniques should enable us to better understand the mechanisms of tumorigenesis, monitor tumor growth, and evaluate the effect of therapeutic interventions for gastric cancer.

This protocol describes the value of dual energy CT and PET/CT imaging methods in tumor imaging and efficacy evaluation. This article demonstrates the research methods and results acquired by dual energy CT and PET/CT to evaluate the gene regulation and targeted treatment of gastric cancer peritoneal metastasis.

Gastric cancer remains fourth in cancer incidence worldwide with a five-year survival of only 20%-30%. Peritoneal metastasis is the most frequent type of ...