301
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von zur Muhlen C, Peter K, Ali ZA, Schneider JE, McAteer MA, Neubauer S, Channon KM, Bode C, Choudhury RP. Visualization of activated platelets by targeted magnetic resonance imaging utilizing conformation-specific antibodies against glycoprotein IIb/IIIa. J Vasc Res 2008; 46:6-14. [PMID: 18515970 PMCID: PMC2914450 DOI: 10.1159/000135660] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2007] [Accepted: 01/19/2008] [Indexed: 12/18/2022] Open
Abstract
Ruptured atherosclerotic plaques, lined with activated platelets, constitute an attractive target for magnetic resonance imaging (MRI). This study evaluated whether microparticles of iron oxide (MPIO) targeting ligand-induced binding sites (LIBS) on the activated conformation of glycoprotein IIb/IIIa could be used to image platelets. MPIO (size: 1 μm) were conjugated to anti-LIBS or control single-chain antibody. Following guidewire injury to mouse femoral artery, platelet adhesion was present after 24 h. Mice were perfused with anti-LIBS-MPIO (or control MPIO) via the left ventricle and 11.7-tesla MRI was performed on femoral arteries ex vivo. A 3D gradient echo sequence attained an isotropic resolution of 25 μm. MPIO binding, quantified by MRI, was 4-fold higher with anti-LIBS-MPIO in comparison to control MPIO (p < 0.01). In histological sections, low signal zones on MRI and MPIO correlated strongly (R2 = 0.72; p < 0.001), indicating accurate MR quantification. In conclusion, anti-LIBS-MPIO bind to activated platelets in mouse arteries, providing a basis for the use of function-specific single-chain antibody-MPIO conjugates for molecular MRI, and represent the first molecular imaging of a conformational change in a surface receptor. This presents an opportunity to specifically image activated platelets involved in acute atherothrombosis with MRI.
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302
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Cellular magnetic resonance imaging: in vivo imaging of melanoma cells in lymph nodes of mice. Neoplasia 2008; 10:207-16. [PMID: 18320065 DOI: 10.1593/neo.07937] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Revised: 12/06/2007] [Accepted: 12/10/2007] [Indexed: 11/18/2022] Open
Abstract
Metastasis is responsible for most deaths due to malignant melanoma. The clinical significance of micrometastases in the lymph is a hotly debated topic, but an improved understanding of the lymphatic spread of cancer remains important for improving cancer survival. Cellular magnetic resonance imaging (MRI) is a newly emerging field of imaging research that is expected to have a large impact on cancer research. In this study, we demonstrate the cellular MRI technology required to reliably image the lymphatic system in mice and to detect iron-labeled metastatic melanoma cells within the mouse lymph nodes. Melanoma cells were implanted directly into the inguinal lymph nodes in mice, and micro-MRI was performed using a customized 1.5-T clinical MRI system. We show cell detection of as few as 100 iron-labeled cells within the lymph node, with injections of larger cell numbers producing increasingly obvious regions of signal void. In addition, we show that cellular MRI allows monitoring of the fate of these cells over time as they develop into intranodal tumors. This technology will allow noninvasive investigations of cellular events in cancer metastasis within an entire animal and will facilitate progress in understanding the mechanisms of metastasis within the lymphatic system.
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303
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Sensitive and automated detection of iron-oxide-labeled cells using phase image cross-correlation analysis. Magn Reson Imaging 2008; 26:618-28. [PMID: 18450402 DOI: 10.1016/j.mri.2008.01.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2007] [Revised: 11/16/2007] [Accepted: 01/06/2008] [Indexed: 11/22/2022]
Abstract
Superparamagnetic iron oxide (SPIO) nanoparticles are increasingly being used to noninvasively track cells, target specific molecules and monitor gene expression in vivo. Contrast changes that are subtle relative to intrinsic sources of contrast present a significant detection challenge. Here, we describe a postprocessing algorithm, called Phase map cross-correlation Detection and Quantification (PDQ), with the purpose of automating identification and quantification of localized accumulations of SPIO agents. The method is designed to sacrifice little flexibility - it works on previously acquired data and allows the use of conventional high-SNR pulse sequences with no extra scan time. We first investigated the theoretical detection limits of PDQ using a simulated dipole field. This method was then applied to three-dimensional (3D) MRI data sets of agarose gel containing isolated dipoles and ex vivo transplanted allogenic rat hearts infiltrated by numerous iron-oxide-labeled macrophages as a result of organ rejection. A simulated dipole field showed this method to be robust in very low signal-to-noise ratio images. Analysis of agarose gel and allogenic rat heart shows that this method can automatically identify and count dipoles while visualizing their biodistribution in 3D renderings. In the heart, this information was used to calculate a quantitative index that may indicate its degree of cellular infiltration.
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304
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von Zur Muhlen C, Sibson NR, Peter K, Campbell SJ, Wilainam P, Grau GE, Bode C, Choudhury RP, Anthony DC. A contrast agent recognizing activated platelets reveals murine cerebral malaria pathology undetectable by conventional MRI. J Clin Invest 2008; 118:1198-207. [PMID: 18274670 DOI: 10.1172/jci33314] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Accepted: 12/19/2007] [Indexed: 01/08/2023] Open
Abstract
Human and murine cerebral malaria are associated with elevated levels of cytokines in the brain and adherence of platelets to the microvasculature. Here we demonstrated that the accumulation of platelets in the brain microvasculature can be detected with MRI, using what we believe to be a novel contrast agent, at a time when the pathology is undetectable by conventional MRI. Ligand-induced binding sites (LIBS) on activated platelet glycoprotein IIb/IIIa receptors were detected in the brains of malaria-infected mice 6 days after inoculation with Plasmodium berghei using microparticles of iron oxide (MPIOs) conjugated to a single-chain antibody specific for the LIBS (LIBS-MPIO). No binding of the LIBS-MPIO contrast agent was detected in uninfected animals. A combination of LIBS-MPIO MRI, confocal microscopy, and transmission electron microscopy revealed that the proinflammatory cytokine TNF-alpha, but not IL-1beta or lymphotoxin-alpha (LT-alpha), induced adherence of platelets to cerebrovascular endothelium. Peak platelet adhesion was found 12 h after TNF-alpha injection and was readily detected with LIBS-MPIO contrast-enhanced MRI. Temporal studies revealed that the level of MPIO-induced contrast was proportional to the number of platelets bound. Thus, the LIBS-MPIO contrast agent enabled noninvasive detection of otherwise undetectable cerebral pathology by in vivo MRI before the appearance of clinical disease, highlighting the potential of targeted contrast agents for diagnostic, mechanistic, and therapeutic studies.
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305
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Klaunberg BA, Davis JA. Considerations for laboratory animal imaging center design and setup. ILAR J 2008; 49:4-16. [PMID: 18172329 DOI: 10.1093/ilar.49.1.4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In vivo animal imaging is an outstanding noninvasive tool to study the pathophysiology of disease or response to therapy; additionally, serial imaging reduces the required number of experimental animals. Because of the tremendous capital investment, we recommend the imaging center be a shared resource to facilitate innovative and productive cross-disciplinary scientific collaborations. A shared center also enables a broader range of imaging, as equipment is often cost prohibitive for smaller facilities. A multitude of factors will determine the architectural design, facility efficiency, and functionality. Important considerations to determine during the planning stages include the types of animals to be imaged, types of imaging studies to be performed, types of imaging equipment and related services to be offered, and the location of the imaging center. Architects must work closely with manufacturers to accommodate equipment-related building specifications; facility planners and veterinarians can provide a practical logistical design that will ensure efficient functionality. Miscellaneous considerations include biosecurity levels, use of radioisotopes, and personnel safety in the imaging environment. The ideal imaging center will include space to house animals and perform necessary preimaging procedures, state-of-the-art in vivo imaging devices and the most up-to-date anesthesia, physiological support, and monitoring equipment. The center staff should include imaging specialists for technical development and data analysis. As it is difficult to provide a comprehensive manual for setting up an in vivo animal imaging center, we offer advice based on our experiences with the National Institutes of Health Mouse Imaging Facility. Because magnetic resonance imaging (MRI) is the most expensive imaging tool, requires specific building design considerations, and poses unique occupational health and safety risks, we focus on MRI as the foundation for an imaging facility design.
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Affiliation(s)
- Brenda A Klaunberg
- Mouse Imaging Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive B1D-69, Bethesda, MD 20892, USA.
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306
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Raschzok N, Morgul MH, Pinkernelle J, Vondran FWR, Billecke N, Kammer NN, Pless G, Adonopoulou MK, Leist C, Stelter L, Teichgraber U, Schwartlander R, Sauer IM. Imaging of primary human hepatocytes performed with micron-sized iron oxide particles and clinical magnetic resonance tomography. J Cell Mol Med 2008; 12:1384-94. [PMID: 18410523 PMCID: PMC3865680 DOI: 10.1111/j.1582-4934.2008.00343.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Transplantation of primary human hepatocytes is a promising approach in certain liver diseases. For the visualization of the hepa-tocytes during and following cell application and the ability of a timely response to potential complications, a non-invasive modality for imaging the transplanted cells has to be established. The aim of this study was to label primary human hepatocytes with micron-sized iron oxide particles (MPIOs), enabling the detection of cells by clinical magnetic resonance imaging (MRI). Primary human hepatocytes isolated from 13 different donors were used for the labelling experiments. Following the dose-finding studies, hepatocytes were incubated with 30 particles/cell for 4 hrs in an adhesion culture. Particle incorporation was investigated via light, fluorescence and electron microscopy, and labelled cells were fixed and analysed in an agarose suspension by a 3.0 Tesla MR scanner. The hepatocytes were enzymatically resuspended and analysed during a 5-day reculture period for viability, total protein, enzyme leakage (aspartate aminotransferase [AST], lactate dehydrogenase [LDH]) and metabolic activity (urea, albumin). A mean uptake of 18 particles/cell could be observed, and the primary human hepatocytes were clearly detectable by MR instrumentation. The particle load was not affected by resuspension and showed no alternations during the culture period. Compared to control groups, labelling and resuspension had no adverse effects on the viability, enzyme leakage and metabolic activity of the human hepatocytes. The feasibility of preparing MPIO-labelled primary human hepatocytes detectable by clinical MR equipment was shown in vitro. MPIO-labelled cells could serve for basic research and quality control in the clinical setting of human hepatocyte transplantation.
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Affiliation(s)
- Nathanael Raschzok
- General, Visceral and Transplantation Surgery, Charité-Campus Virchow, Universitätsmedizin Berlin, Berlin, Germany
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307
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Bankson JA, Ji L, Ravoori M, Han L, Kundra V. Echo-planar imaging for MRI evaluation of intrathoracic tumors in murine models of lung cancer. J Magn Reson Imaging 2008; 27:57-62. [PMID: 18058933 DOI: 10.1002/jmri.21221] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To evaluate the efficacy of fast cardiac- and respiratory-gated MRI acquisition methods for noninvasive assessment of tumor volume in murine models of lung cancer. MATERIALS AND METHODS A total of 21 mice bearing either human small-cell (N417) or non-small-cell (H460) lung tumors were scanned using combinations of respiratory-gated computed tomography (CT) imaging, cardiac- and respiratory-gated multishot spin-echo echo-planar imaging (SE-EPI), and cardiac- and respiratory-gated spoiled gradient echo (SPGR). Tumor depiction at 4.7T was qualitatively and quantitatively compared with CT and tissue cross sections. MRI-based measures of tumor volume were compared with ex vivo measurement of tumor mass. RESULTS Tumors appeared hyperintense on T(2)-weighted EPI images, providing positive intrinsic contrast between tumors and surrounding tissues. Tumor boundaries were better distinguished by EPI and SPGR with T(1)-reducing contrast enhancement when tumor abutted other tissues than by CT or SPGR without contrast. Tumor volumes measured from EPI images correlate well with ex vivo measurements of tumor mass (P < 0.001, r(2) = 0.99) and volume (P < 0.01, r(2) = 0.98) over a wide range of tumor sizes. CONCLUSION Respiratory- and cardiac-gated multishot EPI enables accurate, noninvasive assessment of tumor in murine models of lung cancer using a sequence that requires approximately two minutes to complete.
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Affiliation(s)
- James A Bankson
- Department of Imaging Physics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030-4009, USA.
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308
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Liu W, Dahnke H, Jordan EK, Schaeffter T, Frank JA. In vivo MRI using positive-contrast techniques in detection of cells labeled with superparamagnetic iron oxide nanoparticles. NMR IN BIOMEDICINE 2008; 21:242-50. [PMID: 17566968 DOI: 10.1002/nbm.1187] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Positive-contrast techniques are being developed to increase the detection of magnetically labeled cells in tissues. We evaluated a post-processing positive-contrast technique, susceptibility-gradient mapping (SGM), and compared this approach with two pulse sequences, a gradient-compensation-based "White Marker" technique and an off-resonance-based approach, inversion recovery on-resonance water suppression (IRON), for the detection of superparamagnetic iron oxide (SPIO) nanoparticle-labeled C6 glioma cells implanted in the flanks of nude rats. The SGM, White Marker and IRON positive-contrast images were acquired when the labeled C6 glioma tumors were approximately 5 mm (small), approximately 10 mm (medium) and approximately 20 mm (large) in diameter along the largest dimension to evaluate their sensitivity to the dilution of the SPIO nanoparticles as the tumor cells proliferated. In vivo MRI demonstrated that all three positive-contrast techniques can produce hyperintensities in areas around the labeled flank tumors against a dark background. The number of positive voxels detected around small and medium tumors was significantly greater with the SGM technique than with the White Marker and IRON techniques. For large tumors, the SGM resulted in a similar number of positive voxels to the White Marker technique, and the IRON approach failed to generate positive-contrast images with a 200 Hz suppression band. This study also reveals that hemorrhage appears as hyperintensities on positive-contrast images and may interfere with the detection of SPIO-labeled cells.
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Affiliation(s)
- Wei Liu
- Philips Research Laboratories, Briarcliff Manor, NY 10510, USA.
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309
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von zur Mühlen C, von Elverfeldt D, Choudhury RP, Ender J, Ahrens I, Schwarz M, Hennig J, Bode C, Peter K. Functionalized Magnetic Resonance Contrast Agent Selectively Binds to Glycoprotein IIb/IIIa on Activated Human Platelets under Flow Conditions and Is Detectable at Clinically Relevant Field Strengths. Mol Imaging 2008. [DOI: 10.2310/7290.2008.0008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Affiliation(s)
- Constantin von zur Mühlen
- From the Departments of Cardiology and Angiology and Diagnostic Radiology and Medical Physics, University of Freiburg, Freiburg, Germany; Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK; and Centre for Thrombosis & Myocardial Infarction, Baker Heart Research Institute, Melbourne, Australia
| | - Dominik von Elverfeldt
- From the Departments of Cardiology and Angiology and Diagnostic Radiology and Medical Physics, University of Freiburg, Freiburg, Germany; Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK; and Centre for Thrombosis & Myocardial Infarction, Baker Heart Research Institute, Melbourne, Australia
| | - Robin Paul Choudhury
- From the Departments of Cardiology and Angiology and Diagnostic Radiology and Medical Physics, University of Freiburg, Freiburg, Germany; Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK; and Centre for Thrombosis & Myocardial Infarction, Baker Heart Research Institute, Melbourne, Australia
| | - Janine Ender
- From the Departments of Cardiology and Angiology and Diagnostic Radiology and Medical Physics, University of Freiburg, Freiburg, Germany; Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK; and Centre for Thrombosis & Myocardial Infarction, Baker Heart Research Institute, Melbourne, Australia
| | - Ingo Ahrens
- From the Departments of Cardiology and Angiology and Diagnostic Radiology and Medical Physics, University of Freiburg, Freiburg, Germany; Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK; and Centre for Thrombosis & Myocardial Infarction, Baker Heart Research Institute, Melbourne, Australia
| | - Meike Schwarz
- From the Departments of Cardiology and Angiology and Diagnostic Radiology and Medical Physics, University of Freiburg, Freiburg, Germany; Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK; and Centre for Thrombosis & Myocardial Infarction, Baker Heart Research Institute, Melbourne, Australia
| | - Jürgen Hennig
- From the Departments of Cardiology and Angiology and Diagnostic Radiology and Medical Physics, University of Freiburg, Freiburg, Germany; Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK; and Centre for Thrombosis & Myocardial Infarction, Baker Heart Research Institute, Melbourne, Australia
| | - Christoph Bode
- From the Departments of Cardiology and Angiology and Diagnostic Radiology and Medical Physics, University of Freiburg, Freiburg, Germany; Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK; and Centre for Thrombosis & Myocardial Infarction, Baker Heart Research Institute, Melbourne, Australia
| | - Karlheinz Peter
- From the Departments of Cardiology and Angiology and Diagnostic Radiology and Medical Physics, University of Freiburg, Freiburg, Germany; Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK; and Centre for Thrombosis & Myocardial Infarction, Baker Heart Research Institute, Melbourne, Australia
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310
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von Zur Muhlen C, von Elverfeldt D, Choudhury RP, Ender J, Ahrens I, Schwarz M, Hennig J, Bode C, Peter K. Functionalized magnetic resonance contrast agent selectively binds to glycoprotein IIb/IIIa on activated human platelets under flow conditions and is detectable at clinically relevant field strengths. Mol Imaging 2008; 7:59-67. [PMID: 18706288 PMCID: PMC2912508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023] Open
Abstract
Recent progress in molecular magnetic resonance imaging (MRI) provides the opportunity to image cells and cellular receptors using microparticles of iron oxide (MPIOs). However, imaging targets on vessel walls remains challenging owing to the quantity of contrast agents delivered to areas of interest under shear stress conditions. We evaluated ex vivo binding characteristics of a functional MRI contrast agent to ligand-induced binding sites (LIBSs) on activated glycoprotein IIb/IIIa receptors of human platelets, which were lining rupture-prone atherosclerotic plaques and could therefore facilitate detection of platelet-mediated pathology in atherothrombotic disease. MPIOs were conjugated to anti-LIBS single-chain antibodies (LIBS-MPIO) or control antibodies (control MPIO). Ex vivo binding to human platelet-rich clots in a dose-dependent manner was confirmed on a 3 T clinical MRI scanner and by histology (p < .05 for LIBS-MPIO vs control MPIO). By using a flow chamber setup, significant binding of LIBS-MPIO to a platelet matrix was observed under venous and arterial flow conditions, but not for control MPIO (p < .001). A newly generated MRI contrast agent detects activated human platelets at clinically relevant magnetic field strengths and binds to platelets under venous and arterial flow conditions, conveying high payloads of contrast to specific molecular targets. This may provide the opportunity to identify vulnerable, rupture-prone atherosclerotic plaques via noninvasive MRI.
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311
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Electrical impedance spectroscopy investigation of surfactant–magnetite–polypyrrole particles. J Colloid Interface Sci 2008; 319:441-9. [DOI: 10.1016/j.jcis.2007.11.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Revised: 10/31/2007] [Accepted: 11/06/2007] [Indexed: 11/17/2022]
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312
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Abstract
Gene therapy is a very attractive strategy in experimental cancer therapy. Ideally, the approach aims to deliver therapeutic genes selectively to cancer cells. However, progress in the improvement of gene therapy formulations has been hampered by difficulties in measuring transgene delivery and in quantifying transgene expression in vivo. In clinical trials, endpoints rely almost exclusively on the analysis of biopsies, which provide limited information. Non-invasive monitoring of gene delivery and expression is a very attractive approach as it can be repeated over time in the same patient to provide spatiotemporal information on gene expression on a whole body scale. Thus, imaging methods can uniquely provide researchers and clinicians the ability to directly and serially assess morphological, functional and metabolic changes consequent to molecular and cellular based therapies. This review highlights the various methods currently being developed in preclinical models.
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313
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Atherosclerosis and thrombosis: identification of targets for magnetic resonance imaging. Top Magn Reson Imaging 2008; 18:319-27. [PMID: 18025986 DOI: 10.1097/rmr.0b013e3181598dd8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Imaging techniques are needed that will allow earlier and more refined diagnosis, guide targeted treatment in individual patients and monitor response to that treatment. Magnetic resonance imaging is well-suited to these tasks as it can provide anatomical, structural, and functional data on the arterial wall. Its capabilities are further enhanced by the use of a range of increasingly sophisticated contrast agents that target specific molecules, cells, and biological processes. This article will consider the pathogenesis of atherosclerosis and systematically identify biologically relevant targets for imaging at different stages of disease process.
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314
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Shapiro EM, Medford-Davis LN, Fahmy TM, Dunbar CE, Koretsky AP. Antibody-mediated cell labeling of peripheral T cells with micron-sized iron oxide particles (MPIOs) allows single cell detection by MRI. CONTRAST MEDIA & MOLECULAR IMAGING 2008; 2:147-53. [PMID: 17541955 PMCID: PMC7032004 DOI: 10.1002/cmmi.134] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Labeling cells with iron oxide is a useful tool for MRI based cellular imaging. Here it is demonstrated that peripheral rat T cells can be labeled in whole blood, in vitro, with streptavidin-coated micron-sized iron oxide particles (MPIOs), achieving iron concentrations as high as 60 pg iron per cell. This is 30 times the amount of labeling reported with ultrasmall particles of iron oxide (USPIOs). Labeling was mediated by use of a biotinylated anti-CD5 antibody, which is specific for peripheral T cells. Such labeling allowed the in vitro detection of single lymphocytes by MRI, using conditions well suited for in vivo animal work. Electron microscopic analysis demonstrated that MPIOs remained largely extracellular after labeling, with some evidence of intracellular uptake. Cell viability and early and late cytokine release studies showed no significant differences between labeled and unlabeled cells. Therefore, the use of MPIOs for achieving high iron concentrations for cellular MRI is potentially an effective new modality for non-invasive imaging of lymphocytes.
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Affiliation(s)
- Erik M Shapiro
- Molecular and Cellular Imaging Laboratory, Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT, USA.
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315
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Pinkernelle J, Bruhn H. Colorectal Cancer. Cancer Imaging 2008. [DOI: 10.1016/b978-012374212-4.50106-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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316
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317
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Soenen SJH, Baert J, De Cuyper M. Optimal Conditions for Labelling of 3T3 Fibroblasts with Magnetoliposomes without Affecting Cellular Viability. Chembiochem 2007; 8:2067-77. [DOI: 10.1002/cbic.200700327] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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318
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Abstract
Cell based therapies such as stem cell therapies or adoptive immunotherapies are currently being explored as a potential treatment for a variety of diseases such as Parkinson's disease, diabetes or cancer. However, quantitative and qualitative evaluation of adoptively transferred cells is indispensable for monitoring the efficiency of the treatment. Current approaches mostly analyze transferred cells from peripheral blood, which cannot assess whether transferred cells actually home to and stay in the targeted tissue. Using cell-labeling methods such as direct labeling or transfection with a marker gene in conjunction with various imaging modalities (MRI, optical or nuclear imaging), labeled cells can be followed in vivo in real-time, and their accumulation as well as function in vivo can be monitored and quantified accurately. This method is usually referred to as "cell tracking" or "cell trafficking" and is also being applied in basic biological sciences, exemplified in the evaluation of genes contributing to metastasis. This review focuses on principles of this promising methodology and explains various approaches by highlighting recent examples.
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Affiliation(s)
- J Grimm
- Dept. of Radiology, Memorial Sloan Kettering Cancer Center,1275 York Avenue, New York, NY 10021, USA.
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319
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Cai W, Chen X. Nanoplatforms for targeted molecular imaging in living subjects. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2007; 3:1840-54. [PMID: 17943716 DOI: 10.1002/smll.200700351] [Citation(s) in RCA: 351] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Molecular or personalized medicine is the future of patient management and molecular imaging plays a key role towards this goal. Recently, nanoplatform-based molecular imaging has emerged as an interdisciplinary field, which involves chemistry, engineering, biology, and medicine. Possessing unprecedented potential for early detection, accurate diagnosis, and personalized treatment of diseases, nanoplatforms have been employed in every single biomedical imaging modality, namely, optical imaging, computed tomography, ultrasound, magnetic resonance imaging, single-photon-emission computed tomography, and positron emission tomography. Multifunctionality is the key advantage of nanoplatforms over traditional approaches. Targeting ligands, imaging labels, therapeutic drugs, and many other agents can all be integrated into the nanoplatform to allow for targeted molecular imaging and molecular therapy by encompassing many biological and biophysical barriers. In this Review, we will summarize the current state-of-the-art of nanoplatforms for targeted molecular imaging in living subjects.
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Affiliation(s)
- Weibo Cai
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology and Bio-X Program, Stanford University, Stanford, CA 94305, USA
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320
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McAteer MA, Schneider JE, Ali ZA, Warrick N, Bursill CA, von zur Muhlen C, Greaves DR, Neubauer S, Channon KM, Choudhury RP. Magnetic resonance imaging of endothelial adhesion molecules in mouse atherosclerosis using dual-targeted microparticles of iron oxide. Arterioscler Thromb Vasc Biol 2007; 28:77-83. [PMID: 17962629 DOI: 10.1161/atvbaha.107.145466] [Citation(s) in RCA: 192] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE Microparticles of iron oxide (MPIO) distort magnetic field creating marked contrast effects far exceeding their physical size. We hypothesized that antibody-conjugated MPIO would enable magnetic resonance imaging (MRI) of endothelial cell adhesion molecules in mouse atherosclerosis. METHODS AND RESULTS MPIO (4.5 microm) were conjugated to monoclonal antibodies against vascular cell adhesion molecule-1 (VCAM-MPIO) or P-selectin (P-selectin-MPIO). In vitro, VCAM-MPIO bound, in dose-dependent manner, to tumor necrosis factor (TNF)-alpha stimulated sEND-1 endothelial cells, as quantified by light microscopy (R2=0.94, P=0.03) and by MRI (R2=0.98, P=0.01). VCAM-MPIO binding was blocked by preincubation with soluble VCAM-1. To mimic leukocyte binding, MPIO targeting both VCAM-1 and P-selectin were administered in apolipoprotein E-/- mice. By light microscopy, dual-targeted MPIO binding to endothelium overlying aortic root atherosclerosis was 5- to 7-fold more than P-selectin-MPIO (P<0.05) or VCAM-MPIO (P<0.01) alone. Dual-targeted MPIO, injected intravenously in vivo bound aortic root endothelium and were quantifiable by MRI ex vivo (3.5-fold increase versus control; P<0.01). MPIO were well-tolerated in vivo, with sequestration in the spleen after 24 hours. CONCLUSIONS Dual-ligand MPIO bound to endothelium over atherosclerosis in vivo, under flow conditions. MPIO may provide a functional MRI probe for detecting endothelial-specific markers in a range of vascular pathologies.
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Affiliation(s)
- Martina A McAteer
- Department of Cardiovascular Medicine, University of Oxford, Oxford, OX3 9DU, United Kingdom
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321
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Walczak P, Kedziorek DA, Gilad AA, Barnett BP, Bulte JWM. Applicability and limitations of MR tracking of neural stem cells with asymmetric cell division and rapid turnover: the case of the shiverer dysmyelinated mouse brain. Magn Reson Med 2007; 58:261-9. [PMID: 17654572 DOI: 10.1002/mrm.21280] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
LacZ-transfected C17.2 neural stem cells (NSCs) were labeled with the superparamagnetic iron oxide formulation Feridex prior to ICV injection in shi/shi neonates. Feridex labeling did not alter cell differentiation in vitro and in vivo. Initially, MR images obtained at 11.7T correlated closely to NSC distribution as assessed with anti-dextran and anti-beta-galactosidase double-fluorescent immunostaining. However, at 6 days postgrafting there was already a pronounced mismatch between the hypointense MR signal and the histologically determined cell distribution, with a surprisingly sharp cutoff rather than a gradual decrease of signal. Positive in vivo BrdU labeling of NSCs showed that significant cell replication occurred post-transplantation, causing rapid dilution of Feridex particles between mother and daughter cells toward undetectable levels. Neural differentiation experiments demonstrated asymmetric cell division, explaining the observed sharp cutoff. At later time points (2 weeks), the mismatch further increased by the presence of non-cell-associated Feridex particles resulting from active excretion or cell death. These results are a first demonstration of the inability of MRI to track rapidly dividing and self-renewing, asymmetrically dividing SCs. Therefore, MR cell tracking should only be applied for nonproliferating cells or short-term monitoring of highly-proliferative cells, with mitotic symmetry or asymmetry being important for determining its applicability.
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Affiliation(s)
- P Walczak
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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322
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Magnitsky S, Walton RM, Wolfe JH, Poptani H. Magnetic resonance imaging as a tool for monitoring stem cell migration. NEURODEGENER DIS 2007; 4:314-21. [PMID: 17627135 DOI: 10.1159/000101888] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Noninvasive monitoring of stem cells is an important step in developing stem-cell-based therapies. Among several imaging techniques available, magnetic resonance imaging (MRI) provides an effective way to detect implanted stem cells in live animals. In this mini-review, we discuss the available MRI contrast agents and different cell-labeling strategies used for detection of stem cell migration in the brain. The potential effects of MRI contrast agents on stem cell viability and differentiation are also discussed.
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Affiliation(s)
- S Magnitsky
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
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323
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Soule BP, Hyodo F, Matsumoto KI, Simone NL, Cook JA, Krishna MC, Mitchell JB. Therapeutic and clinical applications of nitroxide compounds. Antioxid Redox Signal 2007; 9:1731-43. [PMID: 17665971 DOI: 10.1089/ars.2007.1722] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Nitroxide compounds have been used for many years as biophysical tools, but only during the past 15-20 years have the many interesting biochemical interactions been discovered and harnessed for therapeutic applications. By modifying oxidative stress and altering the redox status of tissues, nitroxides have the ability to interact with and alter many metabolic processes. This interaction can be exploited for therapeutic and research use, including protection against ionizing radiation, as probes in functional magnetic resonance imaging, cancer prevention and treatment, control of hypertension and weight, and protection from damage resulting from ischemia/reperfusion injury. Although much remains to be done, many applications have been well studied, and some are presently being tested in clinical trials. The therapeutic and research uses of nitroxides are reviewed here, with a focus on the progress from initial development to modern, state-of-the art trials.
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Affiliation(s)
- Benjamin P Soule
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA.
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324
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McAteer MA, Sibson NR, von Zur Muhlen C, Schneider JE, Lowe AS, Warrick N, Channon KM, Anthony DC, Choudhury RP. In vivo magnetic resonance imaging of acute brain inflammation using microparticles of iron oxide. Nat Med 2007; 13:1253-8. [PMID: 17891147 PMCID: PMC2917758 DOI: 10.1038/nm1631] [Citation(s) in RCA: 201] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2007] [Accepted: 07/13/2007] [Indexed: 12/15/2022]
Abstract
Multiple sclerosis is a disease of the central nervous system that is associated with leukocyte recruitment and subsequent inflammation, demyelination and axonal loss. Endothelial vascular cell adhesion molecule-1 (VCAM-1) and its ligand, alpha4beta1 integrin, are key mediators of leukocyte recruitment, and selective inhibitors that bind to the alpha4 subunit of alpha4beta1 substantially reduce clinical relapse in multiple sclerosis. Urgently needed is a molecular imaging technique to accelerate diagnosis, to quantify disease activity and to guide specific therapy. Here we report in vivo detection of VCAM-1 in acute brain inflammation, by magnetic resonance imaging in a mouse model, at a time when pathology is otherwise undetectable. Antibody-conjugated microparticles carrying a large amount of iron oxide provide potent, quantifiable contrast effects that delineate the architecture of activated cerebral blood vessels. Their rapid clearance from blood results in minimal background contrast. This technology is adaptable to monitor the expression of endovascular molecules in vivo in various pathologies.
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Affiliation(s)
- Martina A McAteer
- Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK
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325
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Williams JB, Ye Q, Hitchens TK, Kaufman CL, Ho C. MRI detection of macrophages labeled using micrometer-sized iron oxide particles. J Magn Reson Imaging 2007; 25:1210-8. [PMID: 17520727 DOI: 10.1002/jmri.20930] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To evaluate cellular labeling of immune cells using micron-sized iron oxide particles (MPIOs) and evaluate the MR relaxivity and MRI detection of the labeled cells. MATERIALS AND METHODS Immune cells isolated from mice and rats were labeled with three different sizes of MPIO particles (0.35, 0.90, or 1.63 microm). These labeled cells were characterized using transmission electron microscopy (TEM), fluorescence microscopy, flow cytometry, MR relaxometry, and MRI. RESULTS Macrophage uptake of MPIOs was found to be highest for the 1.63-microm size particles. MR relaxivity measurements indicated greater spin-spin relaxation for MPIO-labeled cells relative to cells labeled with nanometer-sized ultra-small superparamagnetic iron oxide (USPIO) particles with similar iron content. TEM and fluorescence microscopy indicated cellular uptake of multiple MPIO particles per cell. Macrophages labeled with 1.63-microm MPIOs had an average cellular iron uptake of 39.1 pg/cell, corresponding to approximately 35 particles per cell. CONCLUSION Cells labeled with one or more MPIO particles could be readily detected ex vivo at 11.7 Tesla and after infusion of the MPIO-labeled macrophages into the kidney of a rat, hypointense regions of the outer cortex are observed, in vivo, by MRI at 4.7 Tesla.
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Affiliation(s)
- John B Williams
- Pittsburgh NMR Center for Biomedical Research, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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326
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Ebert SN, Taylor DG, Nguyen HL, Kodack DP, Beyers RJ, Xu Y, Yang Z, French BA. Noninvasive tracking of cardiac embryonic stem cells in vivo using magnetic resonance imaging techniques. Stem Cells 2007; 25:2936-44. [PMID: 17690182 DOI: 10.1634/stemcells.2007-0216] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Despite rapid advances in the stem cell field, the ability to identify and track transplanted or migrating stem cells in vivo is limited. To overcome this limitation, we used magnetic resonance imaging (MRI) to detect and follow transplanted stem cells over a period of 28 days in mice using an established myocardial infarction model. Pluripotent mouse embryonic stem (mES) cells were expanded and induced to differentiate into beating cardiomyocytes in vitro. The cardiac-differentiated mES cells were then loaded with superparamagnetic fluorescent microspheres (1.63 microm in diameter) and transplanted into ischemic myocardium immediately following ligation and subsequent reperfusion of the left anterior descending coronary artery. To identify the transplanted stem cells in vivo, MRI was performed using a Varian Inova 4.7 Tesla scanner. Our results show that (a) the cardiac-differentiated mES were effectively loaded with superparamagnetic microspheres in vitro, (b) the microsphere-loaded mES cells continued to beat in culture prior to transplantation, (c) the transplanted mES cells were readily detected in the heart in vivo using noninvasive MRI techniques, (d) the transplanted stem cells were detected in ischemic myocardium for the entire 28-day duration of the study as confirmed by MRI and post-mortem histological analyses, and (e) concurrent functional MRI indicated typical loss of cardiac function, although significant amelioration of remodeling was noted after 28 days in hearts that received transplanted stem cells. These results demonstrate that it is feasible to simultaneously track transplanted stem cells and monitor cardiac function in vivo over an extended period using noninvasive MRI techniques.
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Affiliation(s)
- Steven N Ebert
- Burnett College of Biomedical Sciences, University of Central Florida, 4000 Central Florida Boulevard, Orlando, Florida 32816, USA.
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327
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Wei Q, Seward GK, Hill PA, Patton B, Dimitrov IE, Kuzma NN, Dmochowski IJ. Designing 129Xe NMR biosensors for matrix metalloproteinase detection. J Am Chem Soc 2007; 128:13274-83. [PMID: 17017809 DOI: 10.1021/ja0640501] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Xenon-129 biosensors offer an attractive alternative to conventional MRI contrast agents due to the chemical shift sensitivity and large nuclear magnetic signal of hyperpolarized (129)Xe. Here, we report the first enzyme-responsive (129)Xe NMR biosensor. This compound was synthesized in 13 steps by attaching the consensus peptide substrate for matrix metalloproteinase-7 (MMP-7), an enzyme that is upregulated in many cancers, to the xenon-binding organic cage, cryptophane-A. The final coupling step was achieved on solid support in 80-92% yield via a copper (I)-catalyzed [3+2] cycloaddition. In vitro enzymatic cleavage assays were monitored by HPLC and fluorescence spectroscopy. The biosensor was determined to be an excellent substrate for MMP-7 (K(M) = 43 microM, V(max) = 1.3 x 10(-)(8) M s(-1), k(cat)/K(M) = 7,200 M(-1) s(-1)). Enzymatic cleavage of the tryptophan-containing peptide led to a dramatic decrease in Trp fluorescence, lambda(max) = 358 nm. Stern-Volmer analysis gave an association constant of 9000 +/- 1,000 M(-1) at 298 K between the cage and Trp-containing hexapeptide under enzymatic assay conditions. Most promisingly, (129)Xe NMR spectroscopy distinguished between the intact and cleaved biosensors with a 0.5 ppm difference in chemical shift. This difference most likely reflected a change in the electrostatic environment of (129)Xe, caused by the cleavage of three positively charged residues from the C-terminus. This work provides guidelines for the design and application of new enzyme-responsive (129)Xe NMR biosensors.
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Affiliation(s)
- Qian Wei
- Department of Chemistry, University of Pennsylvania, USA
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328
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Huang X, Bronstein LM, Retrum J, Dufort C, Tsvetkova I, Aniagyei S, Stein B, Stucky G, McKenna B, Remmes N, Baxter D, Kao CC, Dragnea B. Self-assembled virus-like particles with magnetic cores. NANO LETTERS 2007; 7:2407-16. [PMID: 17630812 DOI: 10.1021/nl071083l] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Efficient encapsulation of functionalized spherical nanoparticles by viral protein cages was found to occur even if the nanoparticle is larger than the inner cavity of the native capsid. This result raises the intriguing possibility of reprogramming the self-assembly of viral structural proteins. The iron oxide nanotemplates used in this work are superparamagnetic, with a blocking temperature of about 250 K, making these virus-like particles interesting for applications such as magnetic resonance imaging and biomagnetic materials. Another novel feature of the virus-like particle assembly described in this work is the use of an anionic lipid micelle coat instead of a molecular layer covalently bound to the inorganic nanotemplate. Differences between the two functionalization strategies are discussed.
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Affiliation(s)
- Xinlei Huang
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA
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329
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Slotkin JR, Cahill KS, Tharin SA, Shapiro EM. Cellular magnetic resonance imaging: nanometer and micrometer size particles for noninvasive cell localization. Neurotherapeutics 2007; 4:428-33. [PMID: 17599708 PMCID: PMC7479728 DOI: 10.1016/j.nurt.2007.05.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The use of nanometer and micrometer-sized superparamagnetic iron oxide particles as cellular contrast agents allows for the noninvasive detection of labeled cells on high-resolution magnetic resonance images. The development and application of these techniques to neurologic disorders is likely to accelerate the development of cell transplantation therapies and allow for the detailed study of in vivo cellular biology. This review summarizes the early development of iron oxide-based cellular contrast agents and the more recent application of this technology to noninvasive imaging of cellular transplants. The ability of this technique to allow for the noninvasive detection of in vivo transplants on the single-cell level is highlighted.
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Affiliation(s)
- Jonathan R. Slotkin
- Department of Neurosurgery, The Brigham and Women’s Hospital, The Children’s Hospital, Boston, Harvard Medical School, 02115 Boston, Massachusetts
| | - Kevin S. Cahill
- Department of Neurosurgery, The Brigham and Women’s Hospital, The Children’s Hospital, Boston, Harvard Medical School, 02115 Boston, Massachusetts
| | - Suzanne A. Tharin
- Department of Neurosurgery, The Brigham and Women’s Hospital, The Children’s Hospital, Boston, Harvard Medical School, 02115 Boston, Massachusetts
| | - Erik M. Shapiro
- Department of Diagnostic Radiology, Yale University School of Medicine, 06510 New Haven, Connecticut
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330
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Guzman R, Uchida N, Bliss TM, He D, Christopherson KK, Stellwagen D, Capela A, Greve J, Malenka RC, Moseley ME, Palmer TD, Steinberg GK. Long-term monitoring of transplanted human neural stem cells in developmental and pathological contexts with MRI. Proc Natl Acad Sci U S A 2007; 104:10211-6. [PMID: 17553967 PMCID: PMC1891235 DOI: 10.1073/pnas.0608519104] [Citation(s) in RCA: 288] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Noninvasive monitoring of stem cells, using high-resolution molecular imaging, will be instrumental to improve clinical neural transplantation strategies. We show that labeling of human central nervous system stem cells grown as neurospheres with magnetic nanoparticles does not adversely affect survival, migration, and differentiation or alter neuronal electrophysiological characteristics. Using MRI, we show that human central nervous system stem cells transplanted either to the neonatal, the adult, or the injured rodent brain respond to cues characteristic for the ambient microenvironment resulting in distinct migration patterns. Nanoparticle-labeled human central nervous system stem cells survive long-term and differentiate in a site-specific manner identical to that seen for transplants of unlabeled cells. We also demonstrate the impact of graft location on cell migration and describe magnetic resonance characteristics of graft cell death and subsequent clearance. Knowledge of migration patterns and implementation of noninvasive stem cell tracking might help to improve the design of future clinical neural stem cell transplantation.
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Affiliation(s)
- Raphael Guzman
- *Department of Neurosurgery, Stanford University School of Medicine, 300 Pasteur Drive, R200, Stanford, CA 94305-5327
| | - Nobuko Uchida
- StemCells, Inc., 3155 Porter Drive, Palo Alto, CA 94304-1213
| | - Tonya M. Bliss
- *Department of Neurosurgery, Stanford University School of Medicine, 300 Pasteur Drive, R200, Stanford, CA 94305-5327
| | - Dongping He
- StemCells, Inc., 3155 Porter Drive, Palo Alto, CA 94304-1213
| | | | - David Stellwagen
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, MSLS P104, Stanford, CA 94305-5485; and
| | - Alexandra Capela
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, MSLS P104, Stanford, CA 94305-5485; and
| | - Joan Greve
- Department of Radiology, Lucas Magnetic Resonance Spectroscopy and Imaging Center, Stanford University School of Medicine, P286, Stanford, CA 94022
| | - Robert C. Malenka
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, MSLS P104, Stanford, CA 94305-5485; and
| | - Michael E. Moseley
- Department of Radiology, Lucas Magnetic Resonance Spectroscopy and Imaging Center, Stanford University School of Medicine, P286, Stanford, CA 94022
| | - Theo D. Palmer
- *Department of Neurosurgery, Stanford University School of Medicine, 300 Pasteur Drive, R200, Stanford, CA 94305-5327
| | - Gary K. Steinberg
- *Department of Neurosurgery, Stanford University School of Medicine, 300 Pasteur Drive, R200, Stanford, CA 94305-5327
- To whom correspondence should be addressed. E-mail:
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331
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Abstract
Mice are used in many studies to determine the role of genetic and molecular factors in mammalian development and human congenital diseases. MRI has emerged as a major method for analyzing mutant and transgenic phenotypes in developing mice, at both embryonic and neonatal stages. Progress in this area is reviewed, with emphasis on the use of MRI to analyze cardiovascular and neural development in mice. Comparisons are made with other imaging technologies, including optical and ultrasound imaging, discussing the potential strengths and weaknesses of MRI and identifying the future challenges for MRI in mouse developmental biology.
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Affiliation(s)
- Daniel H Turnbull
- Skirball Institute of Bimolecular Medicine, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA.
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332
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Smirnov P, Gazeau F, Beloeil JC, Doan BT, Wilhelm C, Gillet B. Single-cell detection by gradient echo 9.4 T MRI: a parametric study. CONTRAST MEDIA & MOLECULAR IMAGING 2007; 1:165-74. [PMID: 17193693 DOI: 10.1002/cmmi.104] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Recent studies have shown that cell migration can be monitored in vivo by magnetic resonance imaging after intracellular contrast agent incorporation. This is due to the dephasing effect on proton magnetization of the local magnetic field created by a labelled cell. Anionic iron oxide nanoparticles (AMNP) are among the most efficient and non-toxic contrast agents to be spontaneously taken up by a wide variety of cells. Here we measured the iron load and magnetization of HeLa tumour cells labelled with AMNP, as a function of the external magnetic field. High-resolution gradient echo 9.4 T MRI detected individual labelled cells, whereas spin echo sequences were poorly sensitive. We then conducted a systematic study in order to determine the gradient echo sequence parameters (echo time, cell magnetization and resolution) most suitable for in vivo identification of single cells.
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Affiliation(s)
- P Smirnov
- Laboratoire Matière et Systèmes Complexes, Université Paris 7, Denis Diderot and CNRS UMR 7057, 140, rue de Lourmel, 75015 Paris, France.
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333
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Abstract
The efficacy of therapies based on neural stem cells (NSC) has been demonstrated in preclinical models of several central nervous system (CNS) diseases. Before any potential human application of such promising therapies can be envisaged, there are some important issues that need to be solved. The most relevant one is the requirement for a noninvasive technique capable of monitoring NSC delivery, homing to target sites and trafficking. Knowledge of the location and temporospatial migration of either transplanted or genetically modified NSC is of the utmost importance in analyzing mechanisms of correction and cell distribution. Further, such a technique may represent a crucial step toward clinical application of NSC-based approaches in humans, for both designing successful protocols and monitoring their outcome. Among the diverse imaging approaches available for noninvasive cell tracking, such as nuclear medicine techniques, fluorescence and bioluminescence, magnetic resonance imaging (MRI) has unique advantages. Its high temporospatial resolution, high sensitivity and specificity render MRI one of the most promising imaging modalities available, since it allows dynamic visualization of migration of transplanted cells in animal models and patients during clinically useful time periods. Different cellular and molecular labeling approaches for MRI depiction of NSC are described and discussed in this review, as well as the most relevant issues to be considered in optimizing molecular imaging techniques for clinical application.
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Affiliation(s)
- Letterio S Politi
- Neuroradiology Department, San Raffaele Scientific Institute, Via Olgettina 60, Milano, Italy.
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334
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Beeres SLMA, Bengel FM, Bartunek J, Atsma DE, Hill JM, Vanderheyden M, Penicka M, Schalij MJ, Wijns W, Bax JJ. Role of imaging in cardiac stem cell therapy. J Am Coll Cardiol 2007; 49:1137-48. [PMID: 17367656 DOI: 10.1016/j.jacc.2006.10.072] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2006] [Revised: 10/11/2006] [Accepted: 10/23/2006] [Indexed: 12/17/2022]
Abstract
Stem cell therapy has emerged as a potential therapeutic option for cell death-related heart diseases. Preclinical and a number of early phase human studies suggested that cell therapy may augment perfusion and increase myocardial contractility. The rapid translation into clinical trials has left many issues unresolved, and emphasizes the need for specific techniques to visualize the mechanisms involved. Furthermore, the clinical efficacy of cell therapy remains to be proven. Imaging allows for in vivo tracking of cells and can provide a better understanding in the evaluation of the functional effects of cell-based therapies. In this review, a summary of the most promising imaging techniques for cell tracking is provided. Among these are direct labeling of cells with super-paramagnetic agents, radionuclides, and the use of reporter genes for imaging of transplanted cells. In addition, a comprehensive summary is provided of the currently available studies investigating a cell therapy-related effect on left ventricular function, myocardial perfusion, scar tissue, and myocardial viability.
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Affiliation(s)
- Saskia L M A Beeres
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
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335
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Abstract
Drugs, surgery, and radiation are the traditional modalities of therapy in medicine. To these are being added new therapies based on cells and viruses or their derivatives. In these novel therapies, a cell or viral vector acts as a drug in its own right, altering the host or a disease process to bring about healing. Most of these advances originate from the significant recent advances in molecular medicine, but some have been around for some time. Blood transfusions and cowpox vaccinations are part of the history of medicine...but nevertheless are examples of cell- and viral-based therapies. This article focuses on the modern molecular incarnations of these therapies, and specifically on how imaging is used to track and guide these novel agents. We survey the literature dealing with imaging these new cell and viral particle therapies and provide a framework for understanding publications in this area. Leading technology of gene modifications are the fundamental modifications applied to make these new therapies amenable to imaging.
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Affiliation(s)
- Dawid Schellingerhout
- Neuroradiology Section, Department of Radiology and Experimental Diagnostic Imaging, Division of Diagnostic Imaging, M D Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
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336
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Abstract
Object
An understanding of single glioma cell invasion has been limited by the static picture provided by histological studies. The ability to nondestructively assess cell invasion dynamically in a full 3D volume would improve the quality and quantity of information available from both in vivo and in vitro experiments. The purpose of this study was to observe glioma cell invasion in a 3D in vitro model using a microimaging protocol at 1.5 tesla and to assess the uptake of micron-sized particles of iron oxide (MPIO) and the consequent effects on cell function.
Methods
Rat C6 glioma cells were labeled with MPIO to a sufficient extent to allow single cell detection in vitro without significant effects on cell proliferation or plating efficiency. When placed on agar-coated plates, the cells formed stable multicellular tumor spheroids (MCTSs), which were embedded in collagen type I gel and serially visualized using magnetic resonance (MR) imaging and phase-contrast microscopy over 8 days. The MCTSs initially appeared as large susceptibility artifacts on MR images, but within 2 days, as cells moved away from the main MCTS, small discrete areas of signal loss, possibly due to single cells, could be observed and tracked.
Conclusions
Glioma cell invasion can be nondestructively observed using MR imaging. The sensitivity of MR imaging, along with its ability to represent full 3D volumes noninvasively over time, makes it ideal for longitudinal in vivo cell tracking studies.
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Affiliation(s)
- Lisa M Bernas
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
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337
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Mowat P, Franconi F, Chapon C, Lemaire L, Dorat J, Hindré F, Benoit JP, Richomme P, Le Jeune JJ. Evaluating SPIO-labelled cell MR efficiency by three-dimensional quantitative T2* MRI. NMR IN BIOMEDICINE 2007; 20:21-7. [PMID: 16998951 DOI: 10.1002/nbm.1084] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
An in vitro MR-assay for superparamagnetic iron oxide (SPIO) particle cell labelling assessment via three-dimensional quantitative T(2) (*) MR microscopy was proposed. On high-resolution images, and due to the high susceptibility difference between the particles and the surrounding medium, SPIO internalized in cells induces signal loss which may be counted and measured on T(2) (*) maps. The increase in both labelled cell percentage and the average perturbation volume with an added amount of iron in the incubation medium proved that intracellular iron uptake is dependent upon the initial concentration of incubation iron. It also proved that the observed increases in total cellular iron uptake measured by inductively coupled plasma optical emission spectroscopy are due to both an increase in the iron mass per cell and also an increase in labelled cell concentration. MR results were compared with Prussian blue staining histology. The sensitivity of the MR methodology was then used to distinguish labelling differences for two different types of particle coating. The MRI-assay we proposed is a compulsory tool to optimize labelling efficiency in order to improve in vivo cell detection. Key parameters for detection, such as the percentage of cell labelling, the effect on the image for a given amount of internalized iron and labelling distribution among a cell population, are easily obtained. The comparison of different contrast agents for labelling one cell type, the assessment of one type of contrast agent for labelling different cell types and/or the evaluation of labelling strategies, are possible without having recourse to classical methods, and provide improved accuracy, since the principle is based on intracellular relaxivity.
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Affiliation(s)
- P Mowat
- INSERM U 646 'Ingénierie de la Vectorisation', Angers, France
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338
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Heyn C, Ronald JA, Ramadan SS, Snir JA, Barry AM, MacKenzie LT, Mikulis DJ, Palmieri D, Bronder JL, Steeg PS, Yoneda T, MacDonald IC, Chambers AF, Rutt BK, Foster PJ. In vivo MRI of cancer cell fate at the single-cell level in a mouse model of breast cancer metastasis to the brain. Magn Reson Med 2007; 56:1001-10. [PMID: 17029229 DOI: 10.1002/mrm.21029] [Citation(s) in RCA: 229] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Metastasis (the spread of cancer from a primary tumor to secondary organs) is responsible for most cancer deaths. The ability to follow the fate of a population of tumor cells over time in an experimental animal would provide a powerful new way to monitor the metastatic process. Here we describe a magnetic resonance imaging (MRI) technique that permits the tracking of breast cancer cells in a mouse model of brain metastasis at the single-cell level. Cancer cells that were injected into the left ventricle of the mouse heart and then delivered to the brain were detectable on MR images. This allowed the visualization of the initial delivery and distribution of cells, as well as the growth of tumors from a subset of these cells within the whole intact brain volume. The ability to follow the metastatic process from the single-cell stage through metastatic growth, and to quantify and monitor the presence of solitary undivided cells will facilitate progress in understanding the mechanisms of brain metastasis and tumor dormancy, and the development of therapeutics to treat this disease.
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Affiliation(s)
- Chris Heyn
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
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339
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Benedetto S, Pulito R, Crich SG, Tarone G, Aime S, Silengo L, Hamm J. Quantification of the expression level of integrin receptor alpha(v)beta3 in cell lines and MR imaging with antibody-coated iron oxide particles. Magn Reson Med 2007; 56:711-6. [PMID: 16958071 DOI: 10.1002/mrm.21023] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Targeted imaging requires site-specific accumulation of a contrast agent (CA), and the properties of that agent must be selected according to the abundance of the target to obtain a signal above the detection limit of the instrument. However, numerical estimates of receptors per cell are rarely found in the literature. Integrin receptors would be particularly promising targets because of their accessibility from the blood stream and expression on activated neovascular endothelial cells. We systematically estimated the number of integrin receptors of cell lines and primary cells by flow cytometry analysis. Since integrin receptors are heterodimeric molecules, and alpha(v) forms complexes with various beta subunits, the numbers of alpha(v) and beta(3) subunits are therefore dissimilar. The observed values are 3 . 10(3)-1.4 . 10(4)/cell for alpha(v), and 5.3 . 10(2)-1.1 . 10(4)/cell for beta(3). Despite the low number of exposed receptors, we show that up to single-cell MR visualization can be achieved with the use of iron oxide beads complexed with antibodies as CAs.
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Affiliation(s)
- Sabrina Benedetto
- Department of Genetics, Biology and Biochemistry, University of Turin, Turin, Italy
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340
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Valable S, Barbier EL, Bernaudin M, Roussel S, Segebarth C, Petit E, Rémy C. In vivo MRI tracking of exogenous monocytes/macrophages targeting brain tumors in a rat model of glioma. Neuroimage 2007; 37 Suppl 1:S47-58. [PMID: 17611126 DOI: 10.1016/j.neuroimage.2007.05.041] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Revised: 04/26/2007] [Accepted: 05/08/2007] [Indexed: 01/14/2023] Open
Abstract
This study has shown that murine monocytes/macrophages (Mo/Ma) can be labeled simply and efficiently with large, green-fluorescent, micrometer-sized particles of iron-oxide (MPIO). Neither size nor proliferation rate of the Mo/Ma is significantly affected by this labeling. The labeled Mo/Ma have been administered intravenously to rats that had developed a glioma following stereotactic injection of C6 cells. The labeled Mo/Ma were shown to target the brain tumors, a process that could be monitored non-invasively using T2*-weighted MRI. MRI observations were confirmed by Prussian blue staining, lectin staining and fluorescence histology. Overall, the results of this study suggest that the use of Mo/Ma may be envisaged in the clinic for vectorizing therapeutic agents towards gliomas.
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Affiliation(s)
- Samuel Valable
- Inserm, U836, Grenoble, F-38043, France; Université Joseph Fourier, Grenoble Institut des Neurosciences, Grenoble, F-38043, France
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341
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Zhou R, Acton PD, Ferrari VA. Imaging stem cells implanted in infarcted myocardium. J Am Coll Cardiol 2006; 48:2094-106. [PMID: 17112999 PMCID: PMC2597078 DOI: 10.1016/j.jacc.2006.08.026] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2006] [Revised: 08/14/2006] [Accepted: 08/14/2006] [Indexed: 01/14/2023]
Abstract
Stem cell-based cellular cardiomyoplasty represents a promising therapy for myocardial infarction. Noninvasive imaging techniques would allow the evaluation of survival, migration, and differentiation status of implanted stem cells in the same subject over time. This review describes methods for cell visualization using several corresponding noninvasive imaging modalities, including magnetic resonance imaging, positron emission tomography, single-photon emission computed tomography, and bioluminescent imaging. Reporter-based cell visualization is compared with direct cell labeling for short- and long-term cell tracking.
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Affiliation(s)
- Rong Zhou
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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342
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Mani V, Briley-Saebo KC, Hyafil F, Fayad ZA. Feasibility of in vivo identification of endogenous ferritin with positive contrast MRI in rabbit carotid crush injury using GRASP. Magn Reson Med 2006; 56:1096-106. [PMID: 17036302 DOI: 10.1002/mrm.21060] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In vivo markers that allow for detection of ferritin within atheromatous plaque may be useful for identifying iron-catalyzed hydroxyl-radical formation and subsequent lipid peroxidation. Recently, a positive contrast MR technique--GRadient echo Acquisition for Superparamagnetic particles/suscePtibility (GRASP)--was used to identify the presence of magnetic entities in phantom models. The aim of the current study was to determine the feasibility of using GRASP in conjunction with conventional T(2) (*)-weighted (T(2) (*)W) gradient-echo (GRE) sequences for identifying ferritin/hemosiderin deposition using in vitro and in vivo models of thrombus. In vitro thrombi were prepared by incubating blood with ferritin. MRI was performed using conventional GRE sequences and GRASP. The results indicate that GRASP was able to verify ferritin deposition in in vitro thrombi. In vivo thrombi were created using a crush injury model in rabbits. The signal enhancement obtained using conventional GRE sequences and GRASP was compared with the location of iron deposition by histology. In all of the animals the GRASP signal correlated with signal loss by conventional GRE, and ferritin/hemosiderin deposition by histology. GRASP sequences in combination with conventional GRE sequences may be used to detect the presence of ferritin deposition in in vitro thrombi and in vivo crush-injured rabbit carotid arteries.
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Affiliation(s)
- Venkatesh Mani
- Imaging Science Laboratories, Mount Sinai School of Medicine, New York, New York 10029-6574, USA
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343
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Matsumoto KI, Hyodo F, Matsumoto A, Koretsky AP, Sowers AL, Mitchell JB, Krishna MC. High-resolution mapping of tumor redox status by magnetic resonance imaging using nitroxides as redox-sensitive contrast agents. Clin Cancer Res 2006; 12:2455-62. [PMID: 16638852 DOI: 10.1158/1078-0432.ccr-05-2747] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE There is considerable research directed toward the identification and development of functional contrast agents for medical imaging that superimpose tissue biochemical/molecular information with anatomical structures. Nitroxide radicals were identified as in vivo radioprotectors. Being paramagnetic, they can provide image contrast in magnetic resonance imaging (MRI) and electron paramagnetic resonance imaging (EPRI). The present study sought to determine the efficacy of nitroxide radioprotectors as functional image contrast agents. EXPERIMENTAL DESIGN Nitroxide radioprotectors, which act as contrast agents, were tested by EPRI and MRI to provide tissue redox status information noninvasively. RESULTS Phantom studies showed that the nitroxide, 3-carbamoyl-PROXYL (3CP), undergoes time-dependent reduction to the corresponding diamagnetic hydroxylamine only in the presence of reducing agents. The reduction rates of 3CP obtained by EPRI and MRI were in agreement suggesting the feasibility of using MRI to monitor nitroxide levels in tissues. The levels of 3CP were examined by EPRI and MRI for differences in reduction between muscle and tumor (squamous cell carcinoma) implanted in the hind leg of C3H mice simultaneously. In vivo experiments showed a T1-dependent image intensity enhancement afforded by 3CP which decreased in a time-dependent manner. Reduction of 3CP was found to be the dominant mechanism of contrast loss. The tumor regions exhibited a faster decay rate of the nitroxide compared to muscle (0.097 min(-1) versus 0.067 min(-1), respectively). CONCLUSIONS This study shows that MRI can be successfully used to co-register tissue redox status along with anatomic images, thus providing potentially valuable biochemical information from the region of interest.
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Affiliation(s)
- Ken-Ichiro Matsumoto
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, and Laboratory of Functional and Molecular Imaging, National Institutes of Neurological Disorders and Stroke, NIH, Bethesda, Maryland, USA
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344
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Watson DJ, Walton RM, Magnitsky SG, Bulte JWM, Poptani H, Wolfe JH. Structure-specific patterns of neural stem cell engraftment after transplantation in the adult mouse brain. Hum Gene Ther 2006; 17:693-704. [PMID: 16839269 DOI: 10.1089/hum.2006.17.693] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Transplantation of neural stem cells (NSCs) may be useful for delivering exogenous gene products to the diseased CNS. When NSCs are transplanted into the developing mouse brain, they can migrate extensively and differentiate into cells appropriate to the sites of engraftment, in response to the normal signals directing endogenous cells to their appropriate fates. Much of the prior work on NSC migration in the adult brain has examined directed migration within or toward focal areas of injury such as ischemia, brain tumors, or 6-hydroxydopamine (6-OHDA) lesions. However, treatment of many genetic disorders that affect the CNS will require widespread dissemination of the donor cells in the postnatal brain, because the lesions are typically distributed globally. We therefore tested the ability of NSCs to migrate in the unlesioned adult mouse brain after stereotaxic transplantation into several structures including the cortex and hippocampus. NSC engraftment was monitored in live animals by magnetic resonance imaging (MRI) after superparamagnetic iron oxide (SPIO) labeling of cells. Histological studies demonstrated that the cells engrafted in significantly different patterns within different regions of the brain. In the cerebral cortex, donor cells migrated in all directions from the injection site. The cells maintained an immature phenotype and cortical migration was enhanced by trypsin treatment of the cells, indicating a role for cell surface proteins. In the hippocampus, overall cell survival and migration were lower but there was evidence of neuronal differentiation. In the thalamus, the transplanted cells remained in a consolidated mass at the site of injection. These variations in pattern of engraftment should be taken into account when designing treatment approaches in nonlesion models of neurologic disease.
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Affiliation(s)
- Deborah J Watson
- W.F. Goodman Center for Comparative Medical Genetics, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, 19104, USA
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345
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Abstract
Dendritic cells (DCs) play important roles in the initiation of adaptive immune responses. The transport of antigen from the infection site to the draining lymph node by DCs is a crucial component in this process. Accordingly, immunotherapeutic applications of in vitro-generated DCs require reliable methods experimentally in mice and clinically in patients to monitor the efficiency of their successful lymph node homing after injection. Recent developments of new methods to follow DC migration by non-invasive imaging modalities such as scintigraphy, PET, MRI, or bioluminescence imaging, have gained attraction because of their potential clinical applicability. The current state of the literature and a comparative evaluation of the methods are reported in this review.
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Affiliation(s)
- Dirk Baumjohann
- Department of Dermatology, University Hospital Erlangen, Hartmannstr. 14, 91052 Erlangen, Germany
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346
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Sillerud LO, McDowell AF, Adolphi NL, Serda RE, Adams DP, Vasile MJ, Alam TM. 1H NMR Detection of superparamagnetic nanoparticles at 1T using a microcoil and novel tuning circuit. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 181:181-90. [PMID: 16698297 DOI: 10.1016/j.jmr.2006.04.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Revised: 04/05/2006] [Accepted: 04/11/2006] [Indexed: 05/09/2023]
Abstract
Magnetic beads containing superparamagnetic iron oxide nanoparticles (SPIONs) have been shown to measurably change the nuclear magnetic resonance (NMR) relaxation properties of nearby protons in aqueous solution at distances up to approximately 50 microm. Therefore, the NMR sensitivity for the in vitro detection of single cells or biomolecules labeled with magnetic beads will be maximized with microcoils of this dimension. We have constructed a prototype 550 microm diameter solenoidal microcoil using focused gallium ion milling of a gold/chromium layer. The NMR coil was brought to resonance by means of a novel auxiliary tuning circuit, and used to detect water with a spectral resolution of 2.5 Hz in a 1.04 T (44.2MHz) permanent magnet. The single-scan SNR for water was 137, for a 200 micros pi/2 pulse produced with an RF power of 0.25 mW. The nutation performance of the microcoil was sufficiently good so that the effects of magnetic beads on the relaxation characteristics of the surrounding water could be accurately measured. A solution of magnetic beads (Dynabeads MyOne Streptavidin) in deionized water at a concentration of 1000 beads per nL lowered the T(1) from 1.0 to 0.64 s and the T2 * from 110 to 0.91 ms. Lower concentrations (100 and 10 beads/nL) also resulted in measurable reductions in T2 *, suggesting that low-field, microcoil NMR detection using permanent magnets can serve as a high-sensitivity, miniaturizable detection mechanism for very low concentrations of magnetic beads in biological fluids.
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Affiliation(s)
- Laurel O Sillerud
- Department of Biochemistry and Molecular Biology, University of New Mexico School of Medicine, Cancer Research and Treatment Center, Albuquerque, NM 87131, USA.
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347
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Lebel RM, Menon RS, Bowen CV. Relaxometry model of strong dipolar perturbers for balanced-SSFP: application to quantification of SPIO loaded cells. Magn Reson Med 2006; 55:583-91. [PMID: 16450353 DOI: 10.1002/mrm.20799] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Magnetic resonance microscopy using magnetically labeled cells is an emerging discipline offering the potential for non-destructive studies targeting numerous cellular events in medical research. The present work develops a technique to quantify superparamagnetic iron-oxide (SPIO) loaded cells using fully balanced steady state free precession (b-SSFP) imaging. An analytic model based on phase cancellation was derived for a single particle and extended to predict mono-exponential decay versus echo time in the presence of multiple randomly distributed particles. Numerical models verified phase incoherence as the dominant contrast mechanism and evaluated the model using a full range of tissue decay rates, repetition times, and flip angles. Numerical simulations indicated a relaxation rate enhancement (DeltaR(2b)=0.412 gamma . LMD) proportional to LMD, the local magnetic dose (the additional sample magnetization due to the SPIO particles), a quantity related to the concentration of contrast agent. A phantom model of SPIO loaded cells showed excellent agreement with simulations, demonstrated comparable sensitivity to gradient echo DeltaR(*) (2) enhancements, and 14 times the sensitivity of spin echo DeltaR(2) measurements. We believe this model can be used to facilitate the generation of quantitative maps of targeted cell populations.
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Affiliation(s)
- R Marc Lebel
- Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada
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348
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Shapiro EM, Gonzalez-Perez O, Manuel García-Verdugo J, Alvarez-Buylla A, Koretsky AP. Magnetic resonance imaging of the migration of neuronal precursors generated in the adult rodent brain. Neuroimage 2006; 32:1150-7. [PMID: 16814567 PMCID: PMC4035244 DOI: 10.1016/j.neuroimage.2006.04.219] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2006] [Revised: 04/17/2006] [Accepted: 04/28/2006] [Indexed: 01/09/2023] Open
Abstract
Neural progenitor cells (NPCs) reside within the subventricular zone (SVZ) in rodents. These NPCs give rise to neural precursors in adults that migrate to the olfactory bulb (OB) along a well-defined pathway, the rostral migratory stream (RMS). Here we demonstrate that these NPCs can be labeled, in vivo, in adult rats with fluorescent, micron-sized iron oxide particles (MPIOs), and that magnetic resonance imaging (MRI) can detect migrating neural precursors carrying MPIOs along the RMS to the OB. Immunohistochemistry and electron microscopy indicated that particles were inside GFAP(+) neural progenitor cells in the SVZ, migrating PSA-NCAM(+) and Doublecortin(+) neural precursors within the RMS and OB, and Neu-N(+) mature neurons in the OB. This work demonstrates that in vivo cell labeling of progenitor cells for MRI is possible and enables the serial, non-invasive visualization of endogenous progenitor/precursor cell migration.
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Affiliation(s)
- Erik M Shapiro
- Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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349
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Leuschner C, Kumar CSSR, Hansel W, Soboyejo W, Zhou J, Hormes J. LHRH-conjugated Magnetic Iron Oxide Nanoparticles for Detection of Breast Cancer Metastases. Breast Cancer Res Treat 2006; 99:163-76. [PMID: 16752077 DOI: 10.1007/s10549-006-9199-7] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Accepted: 02/12/2006] [Indexed: 10/24/2022]
Abstract
Targeted delivery of superparamagnetic iron oxide nanoparticles (SPIONs) could facilitate their accumulation in metastatic cancer cells in peripheral tissues, lymph nodes and bones and enhance the sensitivity of magnetic resonance imaging (MRI). The specificities of luteinizing hormone releasing hormone (LHRH) and luteinizing hormone/chorionic gonadotropin (LH/CG)- bound SPIONs were tested in human breast cancer cells in vitro and were found to be dependent on the receptor expression of the target cells, the time of incubation and showed saturation kinetics. In incubations with MDA-MB-435S.luc cells, the highest iron accumulation was 452.6 pg Fe/cell with LHRH-SPIONs, 203.6 pg Fe/cell with beta-CG-SPIONs and 51.3 pg Fe/cell with SPIONs. Incubations at 4 degrees C resulted in 1.1 pg Fe/cell. Co-incubation with the same ligands (betaCG or LHRH) decreased the iron accumulation in each case. LHRH-SPIONs were poorly incorporated by macrophages. Tumors and metastatic cells from breast cancer xenografts were targeted in vivo in a nude mouse model. LHRH-SPION specifically accumulated in cells of human breast cancer xenografts. The amount of LHRH-SPION in the lungs was directly dependent on the number of metastatic cells and amounted to 77.8 pg Fe/metastastic cell. In contrast, unconjugated SPIONs accumulated in the liver, showed poor affinity to the tumor, and were not detectable in metastatic lesions in the lungs. LHRH-SPION accumulated in the cytosolic compartment of the target cells and formed clusters. LHRH-SPIONs did not accumulate in livers of normal mice. In conclusion, LHRH conjugated SPIONs may serve as a contrast agent for MR imaging in vivo and increase the sensitivity for the detection of metastases and disseminated cells in lymph nodes, bones and peripheral organs.
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Affiliation(s)
- Carola Leuschner
- Pennington Biomedical Research Center, LSU System, Baton Rouge, LA 70808, USA.
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350
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Watson DJ, Walton RM, Magnitsky SG, Bulte JW, Poptani H, Wolfe JH. Structure-Specific Patterns of Neural Stem Cell Engraftment After Transplantation in the Adult Mouse Brain. Hum Gene Ther 2006. [DOI: 10.1089/hum.2006.17.ft-220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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