MR Tracking of Capsules & Cells
Wednesday 22 April 2009
Room 316BC 16:00-18:00


Anna V. Moore and Michal Neeman

16:00 518. Development of a Magnetosonoporation-Enhanced Stem Cell Labeling Technique
    Bensheng Qiu1, Daohai Xie, Piotr Walczak2, Jesus Ruiz-Cabello3, Satoshi Minoshima, Jeff W.M. Bulte2, Xiaoming Yang
1Radiology, University of Washington, Seattle, WA, USA; 2Johns Hopkins University; 3Universidad Complutense de Madrid
    Monitoring of stem cells migrating or homing to the targets is essential for the success of stem cell-based therapies. For non-invasive magnetic resonance imaging (MRI) to serially track cell migration, recent efforts have focused on labeling cells with MR contrast agents, such as superparamagnetic iron oxide (SPIO) particles1. The currently-available MR cell labeling techniques include simple incubation and magnetoelectroporation. We attempted to develop an alternative instant cell labeling technique, using ultrasound to facilitate MR-labeling of cells, called magneto-sonoporation (MSP), which is based on the fact that ultrasound can increase cell membrane permeability to external molecules.
16:12 519. Enhanced Cerebral Targeting of Magnetically Labeled Glial Precursor Cells Using the VLA-4/VCAM-1 Adhesion Pathway
    Piotr Walczak1,2, Michael Levy2,3, Michael Gorelik2,3, Douglas A. Kerr2,3, Jeff W.M Bulte1,2
Radiology, Johns Hopkins University, Baltimore, MD, USA; 2Institute for Cell Engineering, Johns Hopkins University, Baltimore, MD, USA; 3Neurology, Johns Hopkins University, Baltimore, MD, USA
    Global cerebral targeting and homing of therapeutic stem cells is of key importance for neurodegenerative disorders having multiple lesions. For cell therapy using intra-arterial injections, it is critical to achieve a high level of initial cellular adhesion to cerebral endothelium before cells can enter the brain parenchyma. We have exploited the use of the VLA-4/VCAM-1 endothelial adhesion pathway to enhance initial endothelial binding by means of transfecting glial restricted precursors (GRPs) with VLA-4. In an LPS-induced inflammatory brain model, Feridex-labeled and VLA-4 over-expressing GRPs showed a dramatically enhanced global cerebral retention as compared to those injected in normal brain.
16:24 520. Development of an in Vivo Functional Assay to Monitor the Effect of SPIO Labeling on Murine Dendritic Cells Used for Cell Therapy in MRI
    Richard Tavaré1, Gopal Varma1, Pervinder Sagoo2, Yakup Tanriver2, Tobias Schaeffter1, Robert Lechler2, Giovanna Lombardi2, Greg Mullen1
Division of Imaging Sciences, King's College London, London, UK; 2Department of Nephrology and Transplantation, King's College London, London, UK
    Dendritic cells are currently being studied as a therapy for both cancer and transplant tolerance. Non-invasive imaging of dendritic cells labeled with superparamagnetic iron oxides (SPIOs) migrating to lymph nodes allows for the monitoring of an efficient cellular therapy. Here, to test the funtion of labeled versus unlabeled cells, the development of an in vivo funtional assay is described, as well as serial imaging of SPIO labeled dendritic cells migrating to the popliteal lymph node.
16:36 521. Using a 19F MRI Tracer Agent for in Vivo Tracking of Human Dendritic Cell Vaccines<
    Brooke M. Helfer1, Aaron D. Nelson1, Jelena M. Janjic2, Eric T. Ahrens2,3, Roberto R. Gil4, Pawel Kalinski5, Jolanda de Vries6, Robbie B. Mailliard1
Research and Development, Celsense, Inc, Pittsburgh, PA, USA; 2Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA; 3Pittsburgh NMR Center for Biomedical Sciences, Carnegie Mellon University, Pittsburgh, PA, USA; 4Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, USA; 5Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA; 6Department of Pediatric Hemato-Oncology, Nijmegen Center for Molecular Life Sciences, Radboud University, Nijmegen, Netherlands
    Dendritic cells (DCs), the central antigen presenting cells of the immune system, have been widely used in clinical trials as anti-cancer vaccines with mixed success. This is partially due to inabilities to non-invasively track adoptively transferred cells after administration. In this study, we show for the first time that clinically relevant human DCs can be effectively labeled in vitro with commercially 19F-tracers without impact to cell health, phenotype, or function, allowing these cells to be visualized post-injection in vivo by 19F-MRI. This study demonstrates the utility and possible clinical application of this method for monitoring patients in cell therapy trials.
16:48 522. Tracking Enhanced Green Fluorescence Protein (EGFP) and Micrometer-Sized Particles of Iron Oxide (MPIO) Labeled Mesenchymal Stem Cells (MSCs) in a Myocardial Infarction Model with Granulocyte-Colony Stimulating Factor (GCSF) Modulation
    Yidong Yang1,2, Yuhui Yang2, Brianna Klein2, Nathan Yanasak2, Xingming Shi3, William Dave Hill4,5, Tom C.-C. Hu1,2
Medical Physics Program, Georgia Institute of Technology, Atlanta, GA, USA; 2Department of Radiology, Medical College of Georgia, Augusta, GA, USA; 3Department of Pathology, Medical College of Georgia, Augusta, GA, USA; 4Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta, GA, USA; 5Veterans Affairs Medical Center, Medical College of Georgia, Augusta, GA, USA
    Synopsis: Stem cells play an important role in tissue repair and regeneration. In this study, MSCs labeled with EGFP and MPIO were transplanted into the mouse bone marrow. It was observed using MRI that the labeled cells infiltrated and engrafted into the myocardial injury and adjacent site and lead to gradual signal attenuation. Furthermore, the GCSF potentially modulated the infiltration rate of labeled MSCs and enhanced the signal attenuation. Results from this study suggest a useful method for the development of drugs designed to modulate the stem cell mobilization process.
17:00 523. Ferritin Overexpression for Molecular Imaging of Transplanted Cells
    Anna Naumova1, Hans Reinecke2,3, Vasily Yarnykh1, Chun Yuan1, Charles Murry2,3
Radiology, University of Washington, Seattle, WA, USA; 2Pathology, University of Washington, Seattle, WA, USA; 3Center for Cardiovascular Biology, Seattle, WA, USA
    We are developing genetically-based technique for molecular imaging of the MRI gene reporter ferritin to enable noninvasive assessment of cell survival and biodistribution after transplantation into infarcted rodent heart. pcDNA3-HAFerr transduction vector encoding ferritin was successfully constructed. Mouse skeletal myoblasts transduced by the vector increased intracellular iron stores, confirmed by Prussian blue staining and yielding a robust detectable effect on T2 and T1 relaxation times in vitro. Ferritin overexpression did not affect cell viability, proliferation and differentiation into multinucleated myotubes. Our pilot studies are encouraging for further in vivo studies of transplanted cells in a beating heart.
17:12 524. MR-Visible and Immunoprotective Alginate Microcapsules for Treatment of Fulminant Liver Failure
    Thomas W. Link1,2, Dian Arifin2,3, Chris M. Long1,2, Piotr Walczak2,3, Naser Muja2,3, Jeff W.M Bulte2,3
Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; 2Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 3Cellular Imaging Section, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA

20-30% of patients with fulminant liver failure die waiting for a transplant due to shortage of donors. Microencapsulated human hepatocytes have the potential to provide a bridge to transplantation. Feridex was incorporated into novel protamine sulfate cross-linked alginate microcapsules to create MR-visible magnetocapsules. Magneto-encapsulated bioluminescent human hepatocytes were characterized in vitro, and injected into the peritoneal cavity of normal mice. Bioluminescent imaging and detection of human albumin by ELISA demonstrated that hepatocytes remained viable and functional for at least 2 weeks. Magnetocapsules were clearly visible as hypointensities throughout the peritoneal cavity.

17:24 525. Facilitated Detection and Quantification of Theragnostic Magnetocapsules by Analyzing MRI Susceptibility Perturbations

Parker H. Mills1,2, Thomas Link3, Aravind Arepally3, Joseph D. Thompson4, Jeff W.M. Bulte3, Eric T. Ahrens1,2
Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA; 2Pittsburgh NMR Center for Biomedical Research, Pittsburgh, PA, USA; 3Institute for Cell Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA; 4Division of Materials Science & Technology, Group 10, Los Alamos National Laboratory, Los Alamos, NM, USA

    Non-invasive studies have monitored the delivery and engraftment of pancreatic islets encapsulated in alginate shells containing Feridex, an FDA-approved superparamagnetic iron-oxide (SPIO). These magnetocapsules are permeable to metabolites, but not native antibodies, thus reducing or avoiding immunosuppressive therapy. Here we apply a newly developed post-processing method, Phase map cross-correlation Detection and Quantification (PDQ), to gel phantoms containing ~103, 450 μm diameter magnetocapsules. PDQ automatically identified and counted magnetocapsules, accurately measuring their magnetic moment (within 1-21% of SQUID-measured values). PDQ can potentially search tissue volumes for absolute magnetocapsule numbers, providing insight on overall islet immunoprotection and survival. PDQ requires no special pulse sequences and works on previously-acquired data.
17:36 526. Novel Trimodal Gadolinium-Gold Microcapsules for Simultaneous Immunoprotection and Positive Contrast MRI, X-Ray, and Ultrasound Imaging of Human Pancreatic Islet Cells
    Dian Respati Arifin1,2, Christopher Long1,2, Assaf A. Gilad1,2, Sameer Manek2,3, Emma Call2, Christophe Alric4, Stephane Roux4, Olivier Tillement4, Thomas W. Link2,3, Aravind Arepally1, Jeff W.M. Bulte1,2
Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 2Cellular Imaging Section, Institute for Cell Engineering, Johns Hopkins University School of Medicine; 3Biomedical Engineering, Johns Hopkins University School of Medicine; 4Laboratoire de Physico-Chimie des Materiaux Luminescents, Universite Claude Bernard Lyon 1, Lyon, France
    Transplantation of pancreatic islet cells is a potential treatment for type I diabetes. Pancreatic islet cells and novel gold nanoparticles functionalized with DTDTPA:gadolinium chelates (GadoGold) were encapsulated inside immunoprotective microcapsules. The viability and functionality of cells encapsulated in GadoGold microcapsules was demonstrated in vitro and in vivo in diabetic mice. The capsules were readily imaged with 9.4 Tesla MRI, micro-CT, and a 40 MHz ultrasound imager. GadoGold microcapsules have potential for cell engraftment providing a means to monitor transplanted cells in vivo using MRI , X-ray and/or ultrasound imaging.
17:48 527. Multifunctional Perfluorinated Microcapsules for Mesenchymal Stem Cell Delivery and Engraftment Tracking Using 19F MRI, X-Ray, and Ultrasound
    Yingli Fu1, Dorota A. Kedziorek1, Ronald Ouwerkerk1, Steven M. Shea2, Nicole Azene1, Aravind Arepally1, Jeff WM Bulte1,3, Robert Krieg4, Frank Wacker1, Dara L. Kraitchman1
Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, USA; 2Imaging and Visualization, Siemens Research Corporate, Inc., Baltimore, MD, USA; 3Institute of Cell Engineering, Johns Hopkins University, Baltimore, MD, USA; 4Siemens AG Healthcare Sector, Erlangen, Germany
    Mesenchymal stem cell (MSC) transplantation is a promising angiogenesis induction therapy for peripheral arterial disease. To immunoprotect MSC after transplantation and monitor MSC delivery and track engraftment noninvasively in vivo, we have developed novel multifunctional perfluoroctylbromide microcapsules (PFOB Caps). Our strategy couples microencapsulation techniques with multi-modality imaging, and converts direct cell labeling and tracking task into microcapsule labeling and tracking task. In vitro, MSC viability within PFOB Caps was enhanced as compared to that in unlabeled capsules. The visibility of PFOB Caps was demonstrated in vitro and in vivo using clinical X-ray, c-arm CT, ultrasound, and 19F MR imaging systems.