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Puskar A, Saadah B, Rauf A, Kasperek SR, Umair M. A primer on contrast agents for magnetic resonance imaging of post‐procedural and follow‐up imaging of islet cell transplant. NANO SELECT 2023. [DOI: 10.1002/nano.202200147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Affiliation(s)
- Anessa Puskar
- Carle Illinois College of Medicine Urbana‐Champaign Urbana Illinois USA
| | - Bara Saadah
- Carle Illinois College of Medicine Urbana‐Champaign Urbana Illinois USA
| | - Asad Rauf
- Carle Illinois College of Medicine Urbana‐Champaign Urbana Illinois USA
| | | | - Muhammad Umair
- Department of Radiology Johns Hopkins Baltimore Maryland USA
- Department of Biomedical Engineering University of Illinois Urbana‐Champaign Urbana Illinois USA
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Padovan S, Carrera C, Catanzaro V, Grange C, Koni M, Digilio G. Glycol Chitosan Functionalized with a Gd(III) Chelate as a Redox-responsive Magnetic Resonance Imaging Probe to Label Cell Embedding Alginate Capsules. Chemistry 2021; 27:12289-12293. [PMID: 34160090 DOI: 10.1002/chem.202101657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Indexed: 12/13/2022]
Abstract
One possibility for the non-invasive imaging of encapsulated cell grafts is to label the lumen of cell embedding capsules with a redox-responsive probe, as an increased extracellular reducing potential can be considered as a marker of hypoxia-induced necrosis. A Gd(III)-HPDO3A-like chelate has been conjugated to glycol-chitosan through a redox-responsive disulphide bond to obtain a contrast agent for Magnetic Resonance Imaging (MRI). Such a compound can be interspersed with fibroblasts within the lumen of alginate-chitosan capsules. Increasing reducing conditions within the extracellular microenvironment lead to the reductive cleavage of the disulphide bond and to the release of gadolinium in the form of a low molecular weight, non-ionic chelate. The efflux of such chelate from capsules is readily detected by a decrease of contrast enhancement in T1 -weighted MR images.
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Affiliation(s)
- Sergio Padovan
- Institute for Biostructures and Bioimages c/o Molecular Biotechnology Centre CNR, Via Nizza 52, 10126, Torino, Italy
| | - Carla Carrera
- Institute for Biostructures and Bioimages c/o Molecular Biotechnology Centre CNR, Via Nizza 52, 10126, Torino, Italy
| | - Valeria Catanzaro
- Department of Science and Technologic Innovation, Università del Piemonte Orientale "Amedeo Avogadro", Viale T. Michel 11, 15121, Alessandria, Italy.,Technology Transfer and Industrial Liaison Department, Politecnico di Torino, Torino, Italy
| | - Cristina Grange
- Department of Medical Sciences, University of Turin, Via Nizza 52, 10126, Torino, Italy
| | - Malvina Koni
- Department of Medical Sciences, University of Turin, Via Nizza 52, 10126, Torino, Italy
| | - Giuseppe Digilio
- Department of Science and Technologic Innovation, Università del Piemonte Orientale "Amedeo Avogadro", Viale T. Michel 11, 15121, Alessandria, Italy
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Taylor NG, Chung SH, Kwansa AL, Johnson RR, Teator AJ, Milliken NJB, Koshlap KM, Yingling YG, Lee YZ, Leibfarth FA. Partially Fluorinated Copolymers as Oxygen Sensitive
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F MRI Agents. Chemistry 2020; 26:9982-9990. [DOI: 10.1002/chem.202001505] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 05/19/2020] [Indexed: 01/03/2023]
Affiliation(s)
- Nicholas G. Taylor
- Department of Chemistry The University of North Carolina at Chapel Hill 125 South Rd Chapel Hill NC 27599 USA
| | - Sang Hun Chung
- Department of Radiology The University of North Carolina at Chapel Hill 101 Manning Dr Chapel Hill NC 27599 USA
| | - Albert L. Kwansa
- Department of Materials Science and Engineering North Carolina State University 911 Partners Way Raleigh NC 27695 USA
| | - Rob R. Johnson
- Department of Chemistry The University of North Carolina at Chapel Hill 125 South Rd Chapel Hill NC 27599 USA
| | - Aaron J. Teator
- Department of Chemistry The University of North Carolina at Chapel Hill 125 South Rd Chapel Hill NC 27599 USA
| | - Nina J. B. Milliken
- Department of Materials Science and Engineering North Carolina State University 911 Partners Way Raleigh NC 27695 USA
| | - Karl M. Koshlap
- Eshelman School of Pharmacy The University of North Carolina at Chapel Hill 301 Pharmacy Ln Chapel Hill NC 27599 USA
| | - Yaroslava G. Yingling
- Department of Materials Science and Engineering North Carolina State University 911 Partners Way Raleigh NC 27695 USA
| | - Yueh Z. Lee
- Department of Radiology The University of North Carolina at Chapel Hill 101 Manning Dr Chapel Hill NC 27599 USA
| | - Frank A. Leibfarth
- Department of Chemistry The University of North Carolina at Chapel Hill 125 South Rd Chapel Hill NC 27599 USA
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Cao R, Avgoustiniatos E, Papas K, de Vos P, Lakey JRT. Mathematical predictions of oxygen availability in micro- and macro-encapsulated human and porcine pancreatic islets. J Biomed Mater Res B Appl Biomater 2019; 108:343-352. [PMID: 31013399 DOI: 10.1002/jbm.b.34393] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 02/12/2019] [Accepted: 04/04/2019] [Indexed: 12/22/2022]
Abstract
Optimal function of immunoisolated islets requires adequate supply of oxygen to metabolically active insulin producing beta-cells. Using mathematical modeling, we investigated the influence of the pO2 on islet insulin secretory capacity and evaluated conditions that could lead to the development of tissue anoxia, modeled for a 300 μm islet in a 500 μm microcapsule or a 500 μm planar, slab-shaped macrocapsule. The pO2 was used to assess the part of islets that contributed to insulin secretion. Assuming a 500 μm macrocapsule with a 300 μm islet, with oxygen consumption rate (OCR) of 100-300 nmol min-1 mg-1 DNA, islets did not develop any necrotic core. The nonfunctional zone (with no insulin secretion if pO2 < 0.1 mmHg) was 0.3% for human islets (OCR ~100 nmol/min/mg DNA) and 35% for porcine islets (OCR ~300 nmol/min/mg DNA). The OCR of the islet preparation is profoundly affected by islet size, with optimal size of <250 μm in diameter (human) or <150 μm (porcine). Our data suggest that microcapsules afford superior oxygen delivery to encapsulated islets than macrocapsules, and optimal islet function can be achieved by encapsulating multiple, small (<150 μm) islets with OCR of ~100 nmol min-1 mg-1 DNA (human islets) or ~200 nmol min-1 mg-1 DNA (porcine islets).
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Affiliation(s)
- Rui Cao
- Department of Surgery, University of California, Irvine, Orange, California
| | | | - Klearchos Papas
- Department of Surgery, University of Arizona, Tucson, Arizona
| | - Paul de Vos
- Departments of Pathology and Laboratory Medicine, Division of Immuno-Endocrinology, University of Groningen, Groningen, The Netherlands
| | - Jonathan R T Lakey
- Department of Surgery, University of California, Irvine, Orange, California
- Department of Biomedical Engineering, University of California, Irvine, California
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6
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Simultaneous spatiotemporal tracking and oxygen sensing of transient implants in vivo using hot-spot MRI and machine learning. Proc Natl Acad Sci U S A 2019; 116:4861-4870. [PMID: 30808810 DOI: 10.1073/pnas.1815909116] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A varying oxygen environment is known to affect cellular function in disease as well as activity of various therapeutics. For transient structures, whether they are unconstrained therapeutic transplants, migrating cells during tumor metastasis, or cell populations induced by an immunological response, the role of oxygen in their fate and function is known to be pivotal albeit not well understood in vivo. To address such a challenge in the case of generation of a bioartificial pancreas, we have combined fluorine magnetic resonance imaging and unsupervised machine learning to monitor over time the spatial arrangement and the oxygen content of implants encapsulating pancreatic islets that are unconstrained in the intraperitoneal (IP) space of healthy and diabetic mice. Statistically significant trends in the postimplantation temporal dependence of oxygen content between aggregates of 0.5-mm or 1.5-mm alginate microcapsules were identified in vivo by looking at their dispersity as well as arrangement in clusters of different size and estimating oxygen content on a pixel-by-pixel basis from thousands of 2D images. Ultimately, we found that this dependence is stronger for decreased implant capsule size consistent with their tendency to also induce a larger immunological response. Beyond the bioartificial pancreas, this work provides a framework for the simultaneous spatiotemporal tracking and oxygen sensing of other cell populations and biomaterials that change over time to better understand and improve therapeutic design across diverse applications such as cellular transplant therapy, treatments preventing metastatic formation, and modulators for improving immunologic response, for all of which oxygen is a major mechanistic component.
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Oxygenation strategies for encapsulated islet and beta cell transplants. Adv Drug Deliv Rev 2019; 139:139-156. [PMID: 31077781 DOI: 10.1016/j.addr.2019.05.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 04/19/2019] [Accepted: 05/04/2019] [Indexed: 02/06/2023]
Abstract
Human allogeneic islet transplantation (ITx) is emerging as a promising treatment option for qualified patients with type 1 diabetes. However, widespread clinical application of allogeneic ITx is hindered by two critical barriers: the need for systemic immunosuppression and the limited supply of human islet tissue. Biocompatible, retrievable immunoisolation devices containing glucose-responsive insulin-secreting tissue may address both critical barriers by enabling the more effective and efficient use of allogeneic islets without immunosuppression in the near-term, and ultimately the use of a cell source with a virtually unlimited supply, such as human stem cell-derived β-cells or xenogeneic (porcine) islets with minimal or no immunosuppression. However, even though encapsulation methods have been developed and immunoprotection has been successfully tested in small and large animal models and to a limited extent in proof-of-concept clinical studies, the effective use of encapsulation approaches to convincingly and consistently treat diabetes in humans has yet to be demonstrated. There is increasing consensus that inadequate oxygen supply is a major factor limiting their clinical translation and routine implementation. Poor oxygenation negatively affects cell viability and β-cell function, and the problem is exacerbated with the high-density seeding required for reasonably-sized clinical encapsulation devices. Approaches for enhanced oxygen delivery to encapsulated tissues in implantable devices are therefore being actively developed and tested. This review summarizes fundamental aspects of islet microarchitecture and β-cell physiology as well as encapsulation approaches highlighting the need for adequate oxygenation; it also evaluates existing and emerging approaches for enhanced oxygen delivery to encapsulation devices, particularly with the advent of β-cell sources from stem cells that may enable the large-scale application of this approach.
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Simkins JW, Stewart PS, Seymour JD. Spatiotemporal mapping of oxygen in a microbially-impacted packed bed using 19F Nuclear magnetic resonance oximetry. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 293:123-133. [PMID: 29940412 PMCID: PMC6047901 DOI: 10.1016/j.jmr.2018.06.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 06/12/2018] [Accepted: 06/13/2018] [Indexed: 06/08/2023]
Abstract
19F magnetic resonance has been used in the medical field for quantifying oxygenation in blood, tissues, and tumors. The 19F NMR oximetry technique exploits the affinity of molecular oxygen for liquid fluorocarbon phases, and the resulting linear dependence of 19F spin-lattice relaxation rate R1 on local oxygen concentration. Bacterial biofilms, aggregates of bacteria encased in a self-secreted matrix of extracellular polymers, are important in environmental, industrial, and clinical settings and oxygen gradients represent a critical determinant of biofilm function. However, measurement of oxygen distribution in biofilms and biofouled porous media is difficult. Here the ability of 19F NMR oximetry to accurately track oxygen profile development in microbial impacted packed bed systems without impacting oxygen transport is demonstrated. Time-stable and inert fluorocarbon containing particles are designed which act as oxygen reporters in porous media systems. Particles are generated by emulsifying and entrapping perfluorooctylbromide (PFOB) into alginate gel, resulting in oxygen-sensing alginate beads that are then used as the solid matrix of the packed bed. 19F oxygenation maps, when combined with 1H velocity maps, allow for insight into the interplay between fluid dynamics and oxygen transport phenomena in these complex biofouled systems. Spatial maps of oxygen consumption rate constants are calculated. The growth characteristics of two bacteria, a non-biofilm forming Escherichia coli and Staphylococcus epidermidis, a strong biofilm-former, are used to demonstrate the novel data provided by the method.
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Affiliation(s)
- Jeffrey W Simkins
- Center for Biofilm Engineering, Montana State University, 366 Barnard Hall, Bozeman, MT 59715, United States; Department of Chemical and Biological Engineering, Montana State University, 306 Cobleigh Hall, Bozeman, MT 59715, United States.
| | - Philip S Stewart
- Center for Biofilm Engineering, Montana State University, 366 Barnard Hall, Bozeman, MT 59715, United States; Department of Chemical and Biological Engineering, Montana State University, 306 Cobleigh Hall, Bozeman, MT 59715, United States.
| | - Joseph D Seymour
- Center for Biofilm Engineering, Montana State University, 366 Barnard Hall, Bozeman, MT 59715, United States; Department of Chemical and Biological Engineering, Montana State University, 306 Cobleigh Hall, Bozeman, MT 59715, United States.
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9
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Paredes-Juarez GA, de Vos P, Bulte JWM. Recent progress in the use and tracking of transplanted islets as a personalized treatment for type 1 diabetes. EXPERT REVIEW OF PRECISION MEDICINE AND DRUG DEVELOPMENT 2017; 2:57-67. [PMID: 29276781 PMCID: PMC5737787 DOI: 10.1080/23808993.2017.1302305] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Type 1 diabetes mellitus (T1DM) is an autoimmune disease in which the pancreas produces insufficient amounts of insulin. T1DM patients require exogenous sources of insulin to maintain euglycemia. Transplantation of naked or microencapsulated pancreatic islets represents an alternative paradigm to obtain an autonomous regulation of blood glucose levels in a controlled and personalized fashion. However, once transplanted, the fate of these personalized cellular therapeutics is largely unknown, justifying the development of non-invasive tracking techniques. AREAS COVERED In vivo imaging of naked pancreatic islet transplantation, monitoring of microencapsulated islet transplantation, visualizing pancreatic inflammation, imaging of molecular-genetic therapeutics, imaging of beta cell function. EXPERT COMMENTARY There are still several hurdles to overcome before (microencapsulated) islet cell transplantation will become a mainstay therapy. Non-invasive imaging methods that can track graft volume, graft rejection, graft function (insulin secretion) microcapsule engraftment, microcapsule rupture, and pancreatic inflammation are currently being developed to design the best experimental transplantation paradigms.
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Affiliation(s)
- Genaro A Paredes-Juarez
- Russell H. Morgan Department of Radiology, Division of Magnetic Resonance Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Paul de Vos
- University Medical Center Groningen (UMCG), Department of Pathology and Medical Biology, Section Immunoendocrinology. Hanzeplein 1, 9713 GZ, Groningen, The Netherlands
| | - Jeff W M Bulte
- Russell H. Morgan Department of Radiology, Division of Magnetic Resonance Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Einstein SA, Weegman BP, Firpo MT, Papas KK, Garwood M. Development and Validation of Noninvasive Magnetic Resonance Relaxometry for the In Vivo Assessment of Tissue-Engineered Graft Oxygenation. Tissue Eng Part C Methods 2016; 22:1009-1017. [PMID: 27758135 PMCID: PMC5116663 DOI: 10.1089/ten.tec.2016.0106] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 09/26/2016] [Indexed: 11/12/2022] Open
Abstract
Techniques to monitor the oxygen partial pressure (pO2) within implanted tissue-engineered grafts (TEGs) are critically necessary for TEG development, but current methods are invasive and inaccurate. In this study, we developed an accurate and noninvasive technique to monitor TEG pO2 utilizing proton (1H) or fluorine (19F) magnetic resonance spectroscopy (MRS) relaxometry. The value of the spin-lattice relaxation rate constant (R1) of some biocompatible compounds is sensitive to dissolved oxygen (and temperature), while insensitive to other external factors. Through this physical mechanism, MRS can measure the pO2 of implanted TEGs. We evaluated six potential MRS pO2 probes and measured their oxygen and temperature sensitivities and their intrinsic R1 values at 16.4 T. Acellular TEGs were constructed by emulsifying porcine plasma with perfluoro-15-crown-5-ether, injecting the emulsion into a macroencapsulation device, and cross-linking the plasma with a thrombin solution. A multiparametric calibration equation containing R1, pO2, and temperature was empirically generated from MRS data and validated with fiber optic (FO) probes in vitro. TEGs were then implanted in a dorsal subcutaneous pocket in a murine model and evaluated with MRS up to 29 days postimplantation. R1 measurements from the TEGs were converted to pO2 values using the established calibration equation and these in vivo pO2 measurements were simultaneously validated with FO probes. Additionally, MRS was used to detect increased pO2 within implanted TEGs that received supplemental oxygen delivery. Finally, based on a comparison of our MRS data with previously reported data, ultra-high-field (16.4 T) is shown to have an advantage for measuring hypoxia with 19F MRS. Results from this study show MRS relaxometry to be a precise, accurate, and noninvasive technique to monitor TEG pO2 in vitro and in vivo.
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Affiliation(s)
- Samuel A. Einstein
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Bradley P. Weegman
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Meri T. Firpo
- Department of Medicine, Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota
| | | | - Michael Garwood
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
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Mahou R, Passemard S, Carvello M, Petrelli A, Noverraz F, Gerber-Lemaire S, Wandrey C. Contribution of polymeric materials to progress in xenotransplantation of microencapsulated cells: a review. Xenotransplantation 2016; 23:179-201. [PMID: 27250036 DOI: 10.1111/xen.12240] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/09/2016] [Indexed: 12/13/2022]
Abstract
Cell microencapsulation and subsequent transplantation of the microencapsulated cells require multidisciplinary approaches. Physical, chemical, biological, engineering, and medical expertise has to be combined. Several natural and synthetic polymeric materials and different technologies have been reported for the preparation of hydrogels, which are suitable to protect cells by microencapsulation. However, owing to the frequent lack of adequate characterization of the hydrogels and their components as well as incomplete description of the technology, many results of in vitro and in vivo studies appear contradictory or cannot reliably be reproduced. This review addresses the state of the art in cell microencapsulation with special focus on microencapsulated cells intended for xenotransplantation cell therapies. The choice of materials, the design and fabrication of the microspheres, as well as the conditions to be met during the cell microencapsulation process, are summarized and discussed prior to presenting research results of in vitro and in vivo studies. Overall, this review will serve to sensitize medically educated specialists for materials and technological aspects of cell microencapsulation.
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Affiliation(s)
- Redouan Mahou
- Interfaculty Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Institute for Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Solène Passemard
- Interfaculty Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Michele Carvello
- Department of Surgery, San Raffaele Scientific Institute, Milan, Italy
| | | | - François Noverraz
- Interfaculty Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Sandrine Gerber-Lemaire
- Interfaculty Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Christine Wandrey
- Interfaculty Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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Schmieder AH, Caruthers SD, Keupp J, Wickline SA, Lanza GM. Recent Advances in 19Fluorine Magnetic Resonance Imaging with Perfluorocarbon Emulsions. ENGINEERING (BEIJING, CHINA) 2015; 1:475-489. [PMID: 27110430 PMCID: PMC4841681 DOI: 10.15302/j-eng-2015103] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The research roots of 19fluorine (19F) magnetic resonance imaging (MRI) date back over 35 years. Over that time span, 1H imaging flourished and was adopted worldwide with an endless array of applications and imaging approaches, making magnetic resonance an indispensable pillar of biomedical diagnostic imaging. For many years during this timeframe, 19F imaging research continued at a slow pace as the various attributes of the technique were explored. However, over the last decade and particularly the last several years, the pace and clinical relevance of 19F imaging has exploded. In part, this is due to advances in MRI instrumentation, 19F/1H coil designs, and ultrafast pulse sequence development for both preclinical and clinical scanners. These achievements, coupled with interest in the molecular imaging of anatomy and physiology, and combined with a cadre of innovative agents, have brought the concept of 19F into early clinical evaluation. In this review, we attempt to provide a slice of this rich history of research and development, with a particular focus on liquid perfluorocarbon compound-based agents.
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Affiliation(s)
- Anne H. Schmieder
- Division of Cardiology, Washington University School of Medical, St. Louis, MO 63110, USA
| | - Shelton D. Caruthers
- Toshiba Medical Research Institute USA, Inc., Cleveland, OH 44143, USA
- Department of Biomedical Engineering, Washington University, St. Louis, MO 63130, USA
| | - Jochen Keupp
- Philips Research Hamburg, Hamburg 22335, Germany
| | - Samuel A. Wickline
- Division of Cardiology, Washington University School of Medical, St. Louis, MO 63110, USA
| | - Gregory M. Lanza
- Division of Cardiology, Washington University School of Medical, St. Louis, MO 63110, USA
- Correspondence author.
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Chan KWY, Liu G, van Zijl PCM, Bulte JWM, McMahon MT. Magnetization transfer contrast MRI for non-invasive assessment of innate and adaptive immune responses against alginate-encapsulated cells. Biomaterials 2014; 35:7811-8. [PMID: 24930848 DOI: 10.1016/j.biomaterials.2014.05.057] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 05/21/2014] [Indexed: 12/24/2022]
Abstract
By means of physical isolation of cells inside semi-permeable hydrogels, encapsulation has been widely used to immunoprotect transplanted cells. While spherical alginate microcapsules are now being used clinically, there still is little known about the patient's immune system response unless biopsies are obtained. We investigated the use of Magnetization Transfer (MT) imaging to non-invasively detect host immune responses against alginate capsules containing xenografted human hepatocytes in four groups of animals, including transplanted empty capsules (-Cells/-IS), capsules with live cells with (+LiveCells/+IS) and without immunosuppression (+LiveCells/-IS), and capsules with apoptotic cells in non-immunosuppressed animals (+DeadCells/-IS). The highest MT ratio (MTR) was found in +LiveCells/-IS, which increased from day 0 by 38% and 53% on days 7 and 14 after transplantation respectively, and corresponded to a distinctive increase in cell infiltration on histology. Furthermore, we show that macromolecular ratio maps based on MT data are more sensitive to cell infiltration and fibrosis than conventional MTR maps. Such maps showed a significant difference between +LiveCells/-IS (0.18 ± 0.02) and +DeadCells/-IS (0.13 ± 0.02) on day 7 (P < 0.01) existed, which was not observed on MTR imaging. We conclude that MT imaging, which is clinically available, can be applied for non-invasive monitoring of the occurrence of a host immune response against encapsulated cells.
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Affiliation(s)
- Kannie W Y Chan
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA; Center of Nanomedicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Baltimore, MD 21205, USA
| | - Guanshu Liu
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Peter C M van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Jeff W M Bulte
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Baltimore, MD 21205, USA
| | - Michael T McMahon
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA; Center of Nanomedicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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14
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Arifin DR, Kedziorek DA, Fu Y, Chan KWY, McMahon MT, Weiss CR, Kraitchman DL, Bulte JWM. Microencapsulated cell tracking. NMR IN BIOMEDICINE 2013; 26:850-859. [PMID: 23225358 PMCID: PMC3655121 DOI: 10.1002/nbm.2894] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 10/08/2012] [Accepted: 10/28/2012] [Indexed: 06/01/2023]
Abstract
Microencapsulation of therapeutic cells has been widely pursued to achieve cellular immunoprotection following transplantation. Initial clinical studies have shown the potential of microencapsulation using semi-permeable alginate layers, but much needs to be learned about the optimal delivery route, in vivo pattern of engraftment, and microcapsule stability over time. In parallel with noninvasive imaging techniques for 'naked' (i.e. unencapsulated) cell tracking, microcapsules have now been endowed with contrast agents that can be visualized by (1) H MRI, (19) F MRI, X-ray/computed tomography and ultrasound imaging. By placing the contrast agent formulation in the extracellular space of the hydrogel, large amounts of contrast agents can be incorporated with negligible toxicity. This has led to a new generation of imaging biomaterials that can render cells visible with multiple imaging modalities.
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Affiliation(s)
- Dian R. Arifin
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Dorota A. Kedziorek
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yingli Fu
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kannie W. Y. Chan
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Michael T. McMahon
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Clifford R. Weiss
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Dara L. Kraitchman
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jeff W. M. Bulte
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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15
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Yu JX, Hallac RR, Chiguru S, Mason RP. New frontiers and developing applications in 19F NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2013; 70:25-49. [PMID: 23540575 PMCID: PMC3613763 DOI: 10.1016/j.pnmrs.2012.10.001] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 10/23/2012] [Indexed: 05/06/2023]
Affiliation(s)
- Jian-Xin Yu
- Laboratory of Prognostic Radiology, Division of Advanced Radiological Sciences, Department of Radiology, UT Southwestern Medical Center, Dallas, Texas
| | - Rami R. Hallac
- Laboratory of Prognostic Radiology, Division of Advanced Radiological Sciences, Department of Radiology, UT Southwestern Medical Center, Dallas, Texas
| | - Srinivas Chiguru
- Laboratory of Prognostic Radiology, Division of Advanced Radiological Sciences, Department of Radiology, UT Southwestern Medical Center, Dallas, Texas
| | - Ralph P. Mason
- Laboratory of Prognostic Radiology, Division of Advanced Radiological Sciences, Department of Radiology, UT Southwestern Medical Center, Dallas, Texas
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16
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Gattás-Asfura KM, Fraker CA, Stabler CL. Perfluorinated alginate for cellular encapsulation. J Biomed Mater Res A 2012; 100:1963-71. [PMID: 22544596 DOI: 10.1002/jbm.a.34052] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 10/31/2011] [Accepted: 11/29/2011] [Indexed: 01/27/2023]
Abstract
Molecules of pentadecafluorooctanoyl chloride (PFC) were grafted onto alginate (Alg) using a linear poly(ethylene glycol) linker and amide bonds. The resulting Alg-PFC material was characterized by proton nuclear magnetic resonance and infrared spectroscopies. The degree of PFC functionalization significantly influenced the physical and chemical properties of Alg-PFC, particularly when the resulting polymer was ionically crosslinked into hydrogels. Alg-PFC hydrogel beads fabricated via Ba(2+) crosslinking were found to match the permeability properties of control alginate beads, except upon swelling over time in culture media. When used to encapsulate MIN6 cells, a beta cell line, Alg-PFC beads demonstrated enhanced cell proliferation over alginate control beads. These results indicate that Alg-PFC hydrogels retain some of the PFC's biological-relevant benefits, such as enhancement of mass transport and bioinertness, to enhance cellular viability within alginate three-dimensional hydrogel environments. We envision these functionalized hydrogels to be particularly useful in the encapsulation of cells with a high metabolic demand, such as pancreatic islets.
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Affiliation(s)
- Kerim M Gattás-Asfura
- Diabetes Research Institute, Miller School of Medicine, University of Miami, Miami, Florida 33136, USA
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17
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Goh F, Sambanis A. In vivo noninvasive monitoring of dissolved oxygen concentration within an implanted tissue-engineered pancreatic construct. Tissue Eng Part C Methods 2011; 17:887-94. [PMID: 21486202 DOI: 10.1089/ten.tec.2011.0098] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The function of an implanted tissue-engineered pancreatic construct is influenced by many in vivo factors; however, assessing its function is based primarily on end physiologic effects. As oxygen significantly affects cell function, we established a dual perfluorocarbon method that utilizes (19)F nuclear magnetic resonance spectroscopy, with perfluorocarbons as oxygen concentration markers, to noninvasively monitor dissolved oxygen concentration (DO) in βTC-tet cell-containing alginate beads and at the implantation milieu. Beads were implanted in the peritoneal cavity of normal and streptozotocin-induced diabetic mice. Using this method, the feasibility of acquiring real-time in vivo DO measurements was demonstrated. Results showed that the mouse peritoneal environment is hypoxic and the DO is further reduced when βTC-tet cell constructs were implanted. The DO within cell-containing beads decreased considerably over time and could be correlated with the relative changes in the number of viable encapsulated cells. The reduction of construct DO due to the metabolic activity of the βTC-tet cells was also compatible with the implant therapeutic function, as observed in the reversal of hyperglycemia in diabetic mice. The importance of these findings in assessing implant functionality and host animal physiology is discussed.
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Affiliation(s)
- Fernie Goh
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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18
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Goh F, Long R, Simpson N, Sambanis A. Dual perfluorocarbon method to noninvasively monitor dissolved oxygen concentration in tissue engineered constructs in vitro and in vivo. Biotechnol Prog 2011; 27:1115-25. [PMID: 21608139 DOI: 10.1002/btpr.619] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 01/17/2011] [Indexed: 11/06/2022]
Abstract
Noninvasive in vivo monitoring of tissue implants provides important correlations between construct function and the observed physiologic effects. As oxygen is a key parameter affecting cell and tissue function, we established a monitoring method that utilizes (19) F nuclear magnetic resonance (NMR) spectroscopy, with perfluorocarbons (PFCs) as oxygen concentration markers, to noninvasively monitor dissolved oxygen concentration (DO) in tissue engineered implants. Specifically, we developed a dual PFC method capable of simultaneously measuring DO within a tissue construct and its surrounding environment, as the latter varies among animals and with physiologic conditions. In vitro studies using an NMR-compatible bioreactor demonstrated the feasibility of this method to monitor the DO within alginate beads containing metabolically active murine insulinoma βTC-tet cells, relative to the DO in the culture medium, under perfusion and static conditions. The DO profiles obtained under static conditions were supported by mathematical simulations of the system. In vivo, the dual PFC method was successful in tracking the oxygenation state of entrapped βTC-tet cells and the surrounding peritoneal DO over 16 days in normal mice. DO measurements correlated well with the extent of cell growth and host cell attachment examined postexplantation. The peritoneal oxygen environment was found to be variable and hypoxic, and significantly lower in the presence of metabolically active cells. The significance of the dual PFC system in providing critical DO measurements for entrapped cells and other tissue constructs, in vitro and in vivo, is discussed.
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Affiliation(s)
- Fernie Goh
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
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19
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Ruiz-Cabello J, Barnett BP, Bottomley PA, Bulte JW. Fluorine (19F) MRS and MRI in biomedicine. NMR IN BIOMEDICINE 2011; 24:114-29. [PMID: 20842758 PMCID: PMC3051284 DOI: 10.1002/nbm.1570] [Citation(s) in RCA: 366] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 04/23/2010] [Accepted: 04/26/2010] [Indexed: 05/04/2023]
Abstract
Shortly after the introduction of (1)H MRI, fluorinated molecules were tested as MR-detectable tracers or contrast agents. Many fluorinated compounds, which are nontoxic and chemically inert, are now being used in a broad range of biomedical applications, including anesthetics, chemotherapeutic agents, and molecules with high oxygen solubility for respiration and blood substitution. These compounds can be monitored by fluorine ((19)F) MRI and/or MRS, providing a noninvasive means to interrogate associated functions in biological systems. As a result of the lack of endogenous fluorine in living organisms, (19)F MRI of 'hotspots' of targeted fluorinated contrast agents has recently opened up new research avenues in molecular and cellular imaging. This includes the specific targeting and imaging of cellular surface epitopes, as well as MRI cell tracking of endogenous macrophages, injected immune cells and stem cell transplants.
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Affiliation(s)
- Jesús Ruiz-Cabello
- Russell H. Morgan Department of Radiology, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Vascular Biology Program and Cellular Imaging Section, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, USA
- NMR Group, Institute of Functional Studies, Complutense University and CIBERES, Madrid, Spain
| | - Brad P. Barnett
- Russell H. Morgan Department of Radiology, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Vascular Biology Program and Cellular Imaging Section, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Paul A. Bottomley
- Russell H. Morgan Department of Radiology, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jeff W.M. Bulte
- Russell H. Morgan Department of Radiology, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Vascular Biology Program and Cellular Imaging Section, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, USA
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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20
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Chen J, Lanza GM, Wickline SA. Quantitative magnetic resonance fluorine imaging: today and tomorrow. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2010; 2:431-40. [PMID: 20564465 DOI: 10.1002/wnan.87] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Fluorine (19F) is a promising moiety for quantitative magnetic resonance imaging (MRI). It possesses comparable magnetic resonance (MR) sensitivity to proton (1H) but exhibits no tissue background signal, allowing specific and selective assessment of the administrated 19F-containing compounds in vivo. Additionally, the MR spectra of 19F-containing compounds exhibited a wide range of chemical shifts (>200 ppm). Therefore, both MR parameters (e.g., spin-lattice relaxation rate R1) and the absolute quantity of molecule can be determined with 19F MRI for unbiased assessment of tissue physiology and pathology. This article reviews quantitative 19F MRI applications for mapping tumor oxygenation, assessing molecular expression in vascular diseases, and tracking labeled stem cells.
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Affiliation(s)
- Junjie Chen
- Consortium for Translational Research in Advanced Imaging and Nanomedicine, St Louis, MO 63108, USA.
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21
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Terreno E, Castelli DD, Viale A, Aime S. Challenges for molecular magnetic resonance imaging. Chem Rev 2010; 110:3019-42. [PMID: 20415475 DOI: 10.1021/cr100025t] [Citation(s) in RCA: 566] [Impact Index Per Article: 40.4] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Enzo Terreno
- Department of Chemistry IFM and Molecular Imaging Center, University of Torino, Torino, Italy
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22
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Srinivas M, Heerschap A, Ahrens ET, Figdor CG, de Vries IJM. (19)F MRI for quantitative in vivo cell tracking. Trends Biotechnol 2010; 28:363-70. [PMID: 20427096 DOI: 10.1016/j.tibtech.2010.04.002] [Citation(s) in RCA: 206] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2010] [Revised: 03/25/2010] [Accepted: 04/02/2010] [Indexed: 02/06/2023]
Abstract
Cellular therapy, including stem cell transplants and dendritic cell vaccines, is typically monitored for dosage optimization, accurate delivery, and localization using noninvasive imaging, of which magnetic resonance imaging (MRI) is a key modality. (19)F MRI retains the advantages of MRI as an imaging modality, and also allows direct detection of labeled cells for unambiguous identification and quantification, unlike typical metal-based contrast agents. Recent developments in (19)F MRI-based in vivo cell quantification, the existing clinical use of (19)F compounds and current explosive interest in cellular therapeutics have brought (19)F imaging technology closer to clinical application. We review the application of (19)F MRI to cell tracking, discussing intracellular (19)F labels, cell labeling and in vivo quantification, as well as the potential clinical uses of (19)F MRI.
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Affiliation(s)
- Mangala Srinivas
- Department of Tumor Immunology, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands
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23
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Caruthers SD, Cyrus T, Winter PM, Wickline SA, Lanza GM. Anti-angiogenic perfluorocarbon nanoparticles for diagnosis and treatment of atherosclerosis. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2010; 1:311-23. [PMID: 20049799 DOI: 10.1002/wnan.9] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Complementary developments in nanotechnology, genomics, proteomics, molecular biology and imaging offer the potential for early, accurate diagnosis. Molecularly-targeted diagnostic imaging agents will allow noninvasive phenotypic characterization of pathologies and, therefore, tailored treatment close to the onset. For atherosclerosis, this includes anti-angiogenic therapy with specifically-targeted drug delivery systems to arrest the development of plaques before they impinge upon the lumen. Additionally, monitoring the application and effects of this targeted therapy in a serial fashion will be important. This review covers the specific application of alpha(nu)beta(3)-targeted anti-angiogenic perfluorocarbon nanoparticles in (1) the detection of molecular markers for atherosclerosis, (2) the immediate verification of drug delivery with image-based prediction of therapy outcomes, and (3) the serial, noninvasive observation of therapeutic efficacy.
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Affiliation(s)
- Shelton D Caruthers
- Washington University School of Medicine and Philips Medical Systems, St. Louis, MO, USA.
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24
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Fort A, Fort N, Ricordi C, Stabler CL. Biohybrid devices and encapsulation technologies for engineering a bioartificial pancreas. Cell Transplant 2009; 17:997-1003. [PMID: 19177836 DOI: 10.3727/096368908786991498] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The use of cell-based treatments in the field of metabolic organs, particularly the pancreas, has seen tremendous growth in recent years. The transplantation of islet of Langerhans cells for the treatment of type 1 diabetes mellitus (T1DM) has allowed for natural glycemic control for patients plagued with hypoglycemia unawareness. The transplantation of islet cells into the portal vein of the liver, however, has presented challenges to the survival of the cells due to inflammation, vascularization, the need for systemic immunosuppression, and physical stress on the graft. New advances in the engineering of appropriate biohybrid devices and encapsulation technologies have led to promising alternatives to traditional methods.
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Affiliation(s)
- Alexander Fort
- Diabetes Research Institute, University of Miami, Miami, FL 33136, USA
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25
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Cell labeling and tracking for experimental models using magnetic resonance imaging. Methods 2009; 48:112-24. [PMID: 19362150 DOI: 10.1016/j.ymeth.2009.03.020] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 03/28/2009] [Indexed: 01/05/2023] Open
Abstract
Magnetic Resonance Imaging (MRI), as one of the most powerful methods in clinical diagnosis, has emerged as an additional method in the field of molecular and cellular imaging. Compared to established molecular imaging methods, MRI provides in vivo images with high resolution. In particularly in the field of cell-based therapy, non-invasively acquired information on temporal changes of cell location linked to high-resolution anatomical information is of great interest. Relatively new approaches like responsive contrast agents or MR imaging reporter gene expression are MRI applications beyond temporal and spatial information on labeled cells towards investigations on functional changes of cells in vivo. MRI-based cell monitoring and tracking studies require prior labeling of the cells under investigation for excellent contrast against the background of host tissue. Here, an overview is provided on contrast generation strategies for MRI of cells. This includes MR contrast agents, various approaches of cell labeling and MRI as well as MR spectroscopic methods used for cell tracking in vivo. Advantages and disadvantages of the particular labeling approaches and methods are discussed. In addition to description of the methods, the emphasis is on the potential but also challenges and shortcomings of this imaging technique for applications that aim to visualize cellular processes in vivo.
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26
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Ramos-Martínez E, Olivos-García A, Saavedra E, Nequiz M, Sánchez EC, Tello E, El-Hafidi M, Saralegui A, Pineda E, Delgado J, Montfort I, Pérez-Tamayo R. Entamoeba histolytica: oxygen resistance and virulence. Int J Parasitol 2008; 39:693-702. [PMID: 19073188 DOI: 10.1016/j.ijpara.2008.11.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 11/07/2008] [Accepted: 11/10/2008] [Indexed: 11/25/2022]
Abstract
Entamoeba histolytica virulence has been attributed to several amoebic molecules such as adhesins, amoebapores and cysteine proteinases, but supporting evidence is either partial or indirect. In this work we compared several in vitro and in vivo features of both virulent E. histolytica (vEh) and non-virulent E. histolytica (nvEh) axenic HM-1 IMSS strains, such as complement resistance, proteinase activity, haemolytic, phagocytic and cytotoxic capacities, survival in mice caecum, and susceptibility to O(2). The only difference observed was a higher in vitro susceptibility of nvEh to O(2). The molecular mechanism of that difference was analyzed in both groups of amoebae after high O(2) exposure. vEh O(2) resistance correlated with: (i) higher O(2) reduction (O(2)(-) and H(2)O(2) production); (ii) increased H(2)O(2) resistance and thiol peroxidase activity, and (iii) reversible pyruvate: ferredoxin oxidoreductase (PFOR) inhibition. Despite the high level of carbonylated proteins in nvEh after O(2) exposure, membrane oxidation by reactive oxygen species was not observed. These results suggest that the virulent phenotype of E. histolytica is related to the greater ability to reduce O(2) and H(2)O(2) as well as PFOR reactivation, whereas nvEh undergoes irreversible PFOR inhibition resulting in metabolic failure and amoebic death.
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Affiliation(s)
- Espiridión Ramos-Martínez
- Departamento de Medicina Experimental Facultad de Medicina, Dr. Balmis 148 Colonia Doctores, Universidad Nacional Autónoma de México, 06720 México DF, CP 04510, Mexico
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27
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Davda S, Bezabeh T. Advances in methods for assessing tumor hypoxia in vivo: implications for treatment planning. Cancer Metastasis Rev 2007; 25:469-80. [PMID: 17029029 DOI: 10.1007/s10555-006-9009-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Tumor hypoxia and its downstream effects have remained of considerable interest for decades due to its negative impact on response to various cancer therapies and promotion of metastasis. Diagnosing hypoxia non-invasively can provide a significant advancement in cancer treatment and is the dire necessity for implementing specific targeted therapies now emerging to treat different aspects of cancer. A variety of techniques are being proposed to do so. However, none of them has yet been established in the clinical arena. This review summarizes the methods currently available to assess tumor hypoxia in vivo and their respective advantages and shortcomings. It also points out the impedances that need to be overcome to establish any particular method in the clinic, along with a broad overview of requirements for further advancement in this sphere of cancer research.
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Affiliation(s)
- Sonal Davda
- Institute for Biodiagnostics, National Research Council, 435 Ellice Avenue, Winnipeg, Manitoba, Canada, R3B 1Y6
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28
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Gross JD, Long RC, Constantinidis I, Sambanis A. Monitoring of dissolved oxygen and cellular bioenergetics within a pancreatic substitute. Biotechnol Bioeng 2007; 98:261-70. [PMID: 17657780 DOI: 10.1002/bit.21421] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This work investigated the use of nuclear magnetic resonance (NMR) spectroscopy in combination with a mathematical model of an encapsulated cell system as a method for rapidly assessing the status of a pancreatic substitute. To validate this method, an in vitro experiment was performed in which the encapsulated cells were perfused in an NMR-compatible system and the dissolved oxygen (DO) concentration of the perfusing medium was lowered from 0.20 to 0.05 mM, then returned to 0.20 mM in a stepwise fashion. The cellular metabolic activity and bioenergetics were evaluated by measuring the oxygen consumption rate (via DO sensors) and nucleotide triphosphate levels (via (31)P NMR). By incorporating a perfluorocarbon emulsion into the alginate beads, the cellular oxygenation state was monitored by measuring the average intrabead DO (AIDO) concentration by (19)F NMR. The in vitro measurements were then compared with model predictions based on the measured external DO concentration and time. Model-predicted cell growth and AIDO closely matched the experimentally acquired data. As the DO concentrations both external to and within the pancreatic substitute are needed to apply this methodology in vivo, the feasibility of measuring the DO concentration from two distinct bead populations implanted in the peritoneal cavity of mice was established. It is concluded that PFC incorporation and (19)F NMR measurements, in combination with a mechanistic model of the encapsulated system, allow the tracking of the state of a pancreatic substitute in vitro and potentially in vivo.
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Affiliation(s)
- Jeffrey D Gross
- Georgia Tech--Emory Center for the Engineering of Living Tissues, Atlanta, Georgia 30322, USA
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29
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Gross JD, Constantinidis I, Sambanis A. Modeling of encapsulated cell systems. J Theor Biol 2006; 244:500-10. [PMID: 17049564 PMCID: PMC2665025 DOI: 10.1016/j.jtbi.2006.08.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Revised: 08/17/2006] [Accepted: 08/21/2006] [Indexed: 12/01/2022]
Abstract
Tissue engineered substitutes consisting of cells in biocompatible materials undergo remodeling with time as a result of cell growth and death processes. With inert matrices that do not directly influence cell growth, remodeling is driven mainly by the concentration of dissolved oxygen (DO). Insulin-secreting cell lines encapsulated in alginate-based beads and used as a pancreatic substitute represent such a case. Beads undergo remodeling with time so that an initially homogeneous distribution of cells is eventually replaced by a dense peripheral ring of primarily viable cells, whereas inner cells are mostly necrotic. This paper develops and analyzes a mathematical model of an encapsulated cell system of spherical geometry that tracks the viable and dead cell densities and the concentration of DO within the construct as functions of radial position and time. Model simulations are compared with experimental histology data on cell distribution. Correlations are then developed between the average intrabead DO concentration (AIDO) and the total viable cell number, as well as between AIDO and the radial cell and DO distributions in beads. As AIDO can be measured experimentally by incorporating a perfluorocarbon emulsion in the beads and acquiring (19)F nuclear magnetic resonance (NMR) spectroscopic data, these correlations can be used to track the remodeling that occurs in the construct in vitro and potentially in vivo. The usefulness of mathematical models in describing the dynamic changes that occur in tissue constructs with time, and the value of these models at obtaining additional information on the system when used interactively with experimental measurements, are discussed.
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Affiliation(s)
- Jeffrey D. Gross
- Georgia Tech-Emory Center for the Engineering of Living Tissues, Atlanta, GA 30332, USA
- Georgia Tech-Emory Department of Biomedical Engineering, Atlanta, GA 30332, USA
| | - I. Constantinidis
- Division of Endocrinology, Department of Medicine, University of Florida, P.O. Box 100226, Gainesville, FL 32610-0226, USA
- National High Magnetic Field Laboratory, 1800 E. Paul Dirac Dr., Tallahassee, FL 32310-3706, USA
| | - A. Sambanis
- Georgia Tech-Emory Center for the Engineering of Living Tissues, Atlanta, GA 30332, USA
- Georgia Tech-Emory Department of Biomedical Engineering, Atlanta, GA 30332, USA
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Corresponding author. Tel.: +1 404 894 2869; fax: +1 404 894 2291. E-mail address: (A. Sambanis)
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30
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Caruthers SD, Neubauer AM, Hockett FD, Lamerichs R, Winter PM, Scott MJ, Gaffney PJ, Wickline SA, Lanza GM. In vitro demonstration using 19F magnetic resonance to augment molecular imaging with paramagnetic perfluorocarbon nanoparticles at 1.5 Tesla. Invest Radiol 2006; 41:305-12. [PMID: 16481914 DOI: 10.1097/01.rli.0000199281.60135.6a] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES This study explored the use of F spectroscopy and imaging with targeted perfluorocarbon nanoparticles for the simultaneous identification of multiple bio-signatures at 1.5 T. MATERIALS AND METHODS Two nanoparticle emulsions with perfluoro-15-crown-5-ether (CE) or perfluorooctylbromide (PFOB) cores were targeted in vitro to fibrin clot phantoms (n=12) in 4 progressive ratios using biotin-avidin interactions. The CE nanoparticles incorporated gadolinium. Fluorine images were acquired using steady-state gradient-echo techniques; spectra using volume-selective and nonselective sampling. RESULTS On conventional T1-weighted imaging, clots with CE nanoparticles enhanced as expected, with intensity decreasing monotonically with CE concentration. All clots were visualized using wide bandwidth fluorine imaging, while restricted bandwidth excitation permitted independent imaging of CE or PFOB nanoparticles. Furthermore, F imaging and spectroscopy allowed visual and quantitative confirmation of relative perfluorocarbon nanoparticle distributions. CONCLUSIONS F MRI/S molecular imaging of perfluorocarbon nanoparticles in vitro suggests that noninvasive phenotypic characterization of pathologic bio-signatures is feasible at clinical field strengths.
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Affiliation(s)
- Shelton D Caruthers
- Division of Cardiology, Washington University Medical School, St. Louis, Missouri 63110, USA.
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31
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Kim YY, Chae SY, Kim S, Byun Y, Bae YH. Improved phenotype of rat islets in a macrocapsule by co-encapsulation with cross-linked Hb. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2006; 16:1521-35. [PMID: 16370059 DOI: 10.1163/156856205774576682] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A number of rat islets were co-encapsulated in a diffusion chamber-type device, i.e., macrocapsule, with a thermoreversible polymeric extracellular matrix (ECM) and bioactive ingredient of cross-linked hemoglobin (Hb-C). The ECM was formed from an aqueous solution of N-isopropyl-acrylamide co-polymers with a small amount of acrylic acid, which exhibited unique sol-gel transition in a temperature range of 30-34 degrees C, without noticeable hysteresis. The incorporation of Hb-C in the islet macrocapsule showed a concentration-dependent effect on insulin secretion and viability of the entrapped islets. Insulin secretion stimulation by glucose and cell viability were more than doubled when compared with a control group (without Hb-C), at an optimum Hb-C concentration of 0.25 mM due to its unique oxygen transporting capacity. Furthermore, 0.25 mM Hb-C in the macrocapsule was able to support islet density up to 1000 islets/device in a 154 microl total volume without negative effects on islet functionality and viability. Hb-C incorporation is an effective strategy for a macrocapsule-type biohybrid artificial pancreas for Type-I diabetes treatment, which can be further developed to a rechargeable system by employing the thermoreversible ECM and designing a proper macrocapsule.
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Affiliation(s)
- Yong Yeon Kim
- Center for Biomaterials and Biotechnology, Department of Materials Science and Engineering, Gwangju Institute of Science and Technology, 1 Oryong-dong, Puk-gu, Gwangju 500-712, South Korea
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Khattak SF, Chin KS, Bhatia SR, Roberts SC. Enhancing oxygen tension and cellular function in alginate cell encapsulation devices through the use of perfluorocarbons. Biotechnol Bioeng 2006; 96:156-66. [PMID: 16917927 DOI: 10.1002/bit.21151] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Encapsulation devices are often hindered by the inability to achieve sufficient oxygen levels for sustaining long-term cell survival both in vivo and in vitro. We have investigated the use of synthetic oxygen carriers in alginate gels to improve metabolic activity and viability of HepG2 cells over time. Perfluorocarbons (PFCs), specifically perfluorotributylamine (PFTBA) and perfluorooctylbromide (PFOB), were emulsified with alginate and used to encapsulate HepG2 cells in a spherical geometry. Cellular state was assessed using the MTT assay and Live/Dead stain as well as through analysis of both lactate and lactate dehydrogenase (LDH) levels which are indirect indicators of oxygen availability. Addition of 1% surfactant resulted in stable emulsions with evenly dispersed PFC droplets of the order of 1-2 microm in diameter, with no influence on cell viability. Both PFCs evaluated were effective in increasing cellular metabolic activity over alginate-only gels. The presence of 10% PFOB significantly increased cellular growth rate by 10% and reduced both intracellular LDH and extracellular lactate levels by 20-40%, improving glucose utilization efficiency. The characteristic drop in cellular metabolic activity upon encapsulation was eliminated with addition of 10% PFC and viability was better maintained throughout the bead, with a significant decrease in necrotic core size. Results were consistent under a physiologically relevant 5% oxygen environment. The incorporation of PFC synthetic oxygen carriers into encapsulation matrices has been successfully applied to improve cell function and viability with implication for a variety of tissue engineering applications.
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Affiliation(s)
- Sarwat F Khattak
- Department of Chemical Engineering, University of Massachusetts, Amherst, MA 01003, USA
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Lanza GM, Winter PM, Neubauer AM, Caruthers SD, Hockett FD, Wickline SA. 1H/19F magnetic resonance molecular imaging with perfluorocarbon nanoparticles. Curr Top Dev Biol 2005; 70:57-76. [PMID: 16338337 DOI: 10.1016/s0070-2153(05)70003-x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Developments in genomics, proteomics, and cell biology are leading a trend toward individualized segmentation and treatment of patients based on early, noninvasive recognition of unique biosignatures. Although developments in molecular imaging have been dominated by nuclear medicine agents in the past, the advent of nanotechnology in the 1990s has led to magnetic resonance (MR) molecular agents that allow detection of sparse biomarkers with a high-resolution imaging modality that can provide both physiological and functional agents. A wide variety of nanoparticulate MR contrast agents have emerged, most of which are superparamagnetic iron oxide-based constructs. However, this chapter focuses on a diagnostic and therapeutic perfluorocarbon (PFC) nanoparticulate platform that is not only effective as a T1-weighted agent, but also supports (19)F MR spectroscopy and imaging. The unique capability of (19)F permits confirmation and segmentation of MR contrast images as well as direct quantification of nanoparticle concentrations within a voxel. PFC nanoparticles have the capability to effectively deliver therapeutic agents to target sites by a novel mechanism termed "contact-facilitated drug delivery." Combined with MR spectroscopy, the concentration of drug delivered to the target site can be determined and the expected response predicted. Moreover, mixtures of nanoparticles with different perfluorocarbon cores can provide a quantitative, multispectral signal, which can be used to simultaneously distinguish the relative concentrations of several important epitopes within a region of interest. In conjunction with rapid improvements in MR imaging, the prospects for personalized medicine and early recognition and treatment of disease have never been better.
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Affiliation(s)
- Gregory M Lanza
- Division of Cardiology, Washington University Medical School, St. Louis, MO 63110, USA
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Nöth U, Rodrigues LM, Robinson SP, Jork A, Zimmermann U, Newell B, Griffiths JR. In vivo determination of tumor oxygenation during growth and in response to carbogen breathing using 15C5-loaded alginate capsules as fluorine-19 magnetic resonance imaging oxygen sensors. Int J Radiat Oncol Biol Phys 2004; 60:909-19. [PMID: 15465209 DOI: 10.1016/j.ijrobp.2004.07.671] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2003] [Revised: 06/28/2004] [Accepted: 07/07/2004] [Indexed: 10/26/2022]
Abstract
PURPOSE The objective was to present a method for the repeated noninvasive measurement of tumor oxygenation (Po(2)) over the whole period of tumor growth. METHODS AND MATERIALS A mixture of tumor homogenate (GH3 prolactinoma) and alginate capsules loaded with perfluoro-15-crown-5-ether (15C5) was injected into the flanks of Wistar Furth rats. The temporal behavior of tumor Po(2) was monitored between Day 1 and 26 after injection using fluorine-19 ((19)F) magnetic resonance imaging (MRI). In addition, the response of tumor Po(2) to modifiers of the tumor microenvironment (carbogen [95% O(2)/5% CO(2)], nicotinamide, and hydralazine) was investigated. RESULTS An initial increase of tumor Po(2), probably reflecting neovascularization, followed by a decrease after Week 2, probably indicating tumor hypoxia or necrosis, were observed. The minimum and maximum average Po(2) +/- SEM observed were 3.3 +/- 2.0 mm Hg on Day 2 and 25.7 +/- 3.8 mm Hg on Day 13, respectively. Carbogen increased the tumor Po(2), whereas nicotinamide caused no significant change and hydralazine induced a significant decrease in tumor oxygenation. CONCLUSIONS A preclinical method for the repeated noninvasive determination of tumor Po(2) was presented. It might help to investigate tumor physiology and the mechanisms of modifiers of the tumor microenvironment and their role in different therapeutic approaches.
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Affiliation(s)
- Ulrike Nöth
- Cancer Research UK Biomedical Magnetic Resonance Research Group, Department of Basic Medical Sciences, St. George's Hospital Medical School, London, United Kingdom.
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Kimura A, Narazaki M, Kanazawa Y, Fujiwara H. 19F Magnetic resonance imaging of perfluorooctanoic acid encapsulated in liposome for biodistribution measurement. Magn Reson Imaging 2004; 22:855-60. [PMID: 15234455 DOI: 10.1016/j.mri.2004.01.060] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2003] [Accepted: 01/30/2004] [Indexed: 11/26/2022]
Abstract
The tissue distribution of perfluorooctanoic acid (PFOA), which is known to show unique biological responses, has been visualized in female mice by (19)F magnetic resonance imaging (MRI) incorporated with the recent advances in microimaging technique. The chemical shift selected fast spin-echo method was applied to acquire in vivo (19)F MR images of PFOA. The in vivo T(1) and T(2) relaxation times of PFOA were proven to be extremely short, which were 140 (+/- 20) ms and 6.3 (+/- 2.2) ms, respectively. To acquire the in vivo (19)F MR images of PFOA, it was necessary to optimize the parameters of signal selection and echo train length. The chemical shift selection was effectively performed by using the (19)F NMR signal of CF(3) group of PFOA without the signal overlapping because the chemical shift difference between the CF(3) and neighbor signals reaches to 14 kHz. The most optimal echo train length to obtain (19)F images efficiently was determined so that the maximum echo time (TE) value in the fast spin-echo sequence was comparable to the in vivo T(2) value. By optimizing these parameters, the in vivo (19)F MR image of PFOA was enabled to obtain efficiently in 12 minutes. As a result, the time course of the accumulation of PFOA into the mouse liver was clearly pursued in the (19)F MR images. Thus, it was concluded that the (19)F MRI becomes the effective method toward the future pharmacological and toxicological studies of perfluorocarboxilic acids.
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Affiliation(s)
- Atsuomi Kimura
- Division of Medical Physics and Engineering, Area of Medical Technology and Science Course of Health Science, Graduate School of Medicine, Osaka University, Osaka, Japan.
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Chae SY, Kim YY, Kim SW, Bae YH. Prolonged Glucose Normalization of Streptozotocin-Induced Diabetic Mice by Transplantation of Rat Islets Coencapsulated with Crosslinked Hemoglobin. Transplantation 2004; 78:392-7. [PMID: 15316367 DOI: 10.1097/01.tp.0000128617.14309.26] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Facilitated oxygen transport by crosslinked hemoglobin (Hb-C) in islet microcapsules may promote transplanted graft function by improving islet functionality and viability. METHODS This study investigated the in vivo efficacy of Hb-C as an oxygen carrier on the functionality and viability of microencapsulated rat islets. Hb-C by poly(ethylene glycol) was introduced into rat islet microcapsules (alginate-poly[L-lysine]-alginate microcapsule), and 500 suboptimal encapsulated islets were xenotransplanted into each streptozotocin-induced diabetic BALB/c mouse. The graft efficacy over time was evaluated by measuring nonfasting blood glucose level, body weight, and glucose tolerance. RESULTS Mice that received Hb-C-containing microcapsules maintained normoglycemia for at least 8 weeks with normal glucose clearance, determined by intraperitoneal glucose tolerance test. However, the mice that received the conventional control islet microcapsule (without Hb-C) transplant showed graft failure in 4 weeks, exhibited by hyperglycemia, weight loss, and deteriorated glucose tolerance. Severe central necrosis of retrieved islets was observed for the control islet capsule graft after 8 weeks. CONCLUSION The present study revealed that the incorporation of Hb-C in islet microcapsules promotes graft function for a longer period of time than the conventional islet capsules. Therefore, Hb-C coencapsulation is a potential approach for prolonging graft function of islet microcapsules and reducing the number of islets required for normoglycemia.
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Affiliation(s)
- Su Young Chae
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, USA
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Affiliation(s)
- Dawen Zhao
- Department of The University of Texas Southwestern Medicial Center at Dallas, 75390, USA
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Morawski AM, Winter PM, Yu X, Fuhrhop RW, Scott MJ, Hockett F, Robertson JD, Gaffney PJ, Lanza GM, Wickline SA. Quantitative ?magnetic resonance immunohistochemistry? with ligand-targeted19F nanoparticles. Magn Reson Med 2004; 52:1255-62. [PMID: 15562481 DOI: 10.1002/mrm.20287] [Citation(s) in RCA: 152] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Unstable atherosclerotic plaques exhibit microdeposits of fibrin that may indicate the potential for a future rupture. However, current methods for evaluating the stage of an atherosclerotic lesion only involve characterizing the level of vessel stenosis, without delineating which lesions are beginning to rupture. Previous work has shown that fibrin-targeted, liquid perfluorocarbon nanoparticles, which carry a high payload of gadolinium, have a high sensitivity and specificity for detecting fibrin with clinical (1)H MRI. In this work, the perfluorocarbon content of the targeted nanoparticles is exploited for the purposes of (19)F imaging and spectroscopy to demonstrate a method for quantifiable molecular imaging of fibrin in vitro at 4.7 T. Additionally, the quantity of bound nanoparticles formulated with different perfluorocarbon species was calculated using spectroscopy. Results indicate that the high degree of nanoparticle binding to fibrin clots and the lack of background (19)F signal allow accurate quantification using spectroscopy at 4.7 T, as corroborated with proton relaxation rate measurements at 1.5 T and trace element (gadolinium) analysis. Finally, the extension of these techniques to a clinically relevant application, the evaluation of the fibrin burden within an ex vivo human carotid endarterectomy sample, demonstrates the potential use of these particles for uniquely identifying unstable atherosclerotic lesions in vivo.
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Affiliation(s)
- Anne M Morawski
- Department of Medicine, Washington University, Saint Louis, Missouri 63110, USA
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King A, Andersson A, Strand BL, Lau J, Skjåk-Braek G, Sandler S. The role of capsule composition and biologic responses in the function of transplanted microencapsulated islets of Langerhans. Transplantation 2003; 76:275-9. [PMID: 12883179 DOI: 10.1097/01.tp.0000078625.29988.0a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Aileen King
- Department of Medical Cell Biology, Biomedical Centre, Uppsala University, Uppsala, Sweden.
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Sun PZ, Schoening ZB, Jasanoff A. In vivo oxygen detection using exogenous hemoglobin as a contrast agent in magnetic resonance microscopy. Magn Reson Med 2003; 49:609-14. [PMID: 12652529 DOI: 10.1002/mrm.10405] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
In this work we show that exogenous molecular hemoglobin (Hb) is an effective indicator of relative local oxygen tension in magnetic resonance (MR) microscopy studies in vivo. This approach is more sensitive than other MRI oximetry methods; it can be used at higher resolutions and in specimens with no blood oxygen level-dependent (BOLD) effects. Using injection studies in flies, we show that Hb can permeate through relatively dense neural tissue, and that it is not obviously disruptive to physiology. Hb-injected flies show large changes in signal intensity (40-50%) when external O(2) levels are manipulated artificially from 0% to 21%. Oxygen-dependent contrast changes produced by exogenous Hb are detected in T(2)-weighted imaging experiments, and can be roughly calibrated if necessary. These studies demonstrate the feasibility of a contrast agent technique that may be useful for functional MRI (fMRI) studies of metabolism at tens of microns resolution.
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Affiliation(s)
- Phillip Z Sun
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA
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Huang MQ, Ye Q, Williams DS, Ho C. MRI of lungs using partial liquid ventilation with water-in-perfluorocarbon emulsions. Magn Reson Med 2002; 48:487-92. [PMID: 12210913 DOI: 10.1002/mrm.10231] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A novel (1)H-MRI contrast modality for rat lungs has been developed using water-in-perfluorocarbon (PFC) emulsions for partial liquid ventilation (PLV). The feasibility of the new ventilation protocol for (1)H-MRI studies of lungs has been demonstrated. (1)H-MR images of lungs have been obtained with sensitivity and spatial resolution higher than those of the (19)F-MRI of lungs previously reported. Diffusion-weighted MRI measurements of lungs showed that the results obtained are related to the pulmonary architecture and functional properties of lungs. Although the methodology needs further improvement and evaluation, it appears to have great potential in a wide range of new applications in the field of lung MRI, such as in vivo detection of lung cancer, emphysema, and allograft rejection following lung transplantation. The ability of this technique to achieve high-quality MR images of lungs, together with its technical simplicity, stability, and low cost, makes this method a promising imaging technique for the lungs.
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Affiliation(s)
- Ming Qiang Huang
- Pittsburgh NMR Center for Biomedical Research, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
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Zimmermann U, Thürmer F, Jork A, Weber M, Mimietz S, Hillgärtner M, Brunnenmeier F, Zimmermann H, Westphal I, Fuhr G, Nöth U, Haase A, Steinert A, Hendrich C. A novel class of amitogenic alginate microcapsules for long-term immunoisolated transplantation. Ann N Y Acad Sci 2001; 944:199-215. [PMID: 11797670 DOI: 10.1111/j.1749-6632.2001.tb03833.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the light of results of clinical trials with immunoisolated human parathyroid tissue Ba2+-alginate capsules were developed that meet the requirements for long-term immunoisolated transplantation of (allogeneic and xenogeneic) cells and tissue fragments. Biocompatibility of the capsules was achieved by subjecting high-M alginate extracted from freshly collected brown algae to a simple purification protocol that removes quantitatively mitogenic and cytotoxic impurities without degradation of the alginate polymers. The final ultra-high-viscosity, clinical-grade (UHV/CG) product did not evoke any (significant) foreign body reaction in BB rats or in baboons. Similarly, the very sensitive pERK assay did not reveal any mitogenic impurities. Encapsulated cells also exhibited excellent secretory properties under in vitro conditions. Despite biocompatible material, pericapsular fibrosis is also induced by imperfect capsule surfaces that can favor cell attachment and migration under the release of material traces. This material can interact with free end monomers of the alginate polymers under formation of mitogenic advanced glycation products. Smooth surfaces, and thus topographical biocompatibility of the capsules (visualized by atomic force microscopy), can be generated by appropriate crosslinking of the UHV/CG-alginate with Ba2+ and simultaneous suppression of capsule swelling by incorporation of proteins and/or perfluorocarbons (i.e., medically approved compounds with high oxygen capacity). Perfluorocarbon-loaded alginate capsules allow long-term non-invasive monitoring of the location and the oxygen supply of the transplants by using 19F-MRI. Transplantation studies in rats demonstrated that these capsules were functional over a period of more than two years.
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Affiliation(s)
- U Zimmermann
- Lehrstuhl für Biotechnologie, Biozentrum, Universität Würzburg, Germany.
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Kürschner M, Nielsen K, von Langen JR, Schenk WA, Zimmermann U, Sukhorukov VL. Effect of fluorine substitution on the interaction of lipophilic ions with the plasma membrane of mammalian cells. Biophys J 2000; 79:1490-7. [PMID: 10969010 PMCID: PMC1301042 DOI: 10.1016/s0006-3495(00)76400-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The effects of the anionic tungsten carbonyl complex [W(CO)(5)SC(6)H(5)](-) and its fluorinated analog [W(CO)(5)SC(6)F(5)](-) on the electrical properties of the plasma membrane of mouse myeloma cells were studied by the single-cell electrorotation technique. At micromolar concentrations, both compounds gave rise to an additional antifield peak in the rotational spectra of cells, indicating that the plasma membrane displayed a strong dielectric dispersion. This means that both tungsten derivatives act as lipophilic ions that are able to introduce large amounts of mobile charges into the plasma membrane. The analysis of the rotational spectra allowed the evaluation not only of the passive electric properties of the plasma membrane and cytoplasm, but also of the ion transport parameters, such as the surface concentration, partition coefficient, and translocation rate constant of the lipophilic anions dissolved in the plasma membrane. Comparison of the membrane transport parameters for the two anions showed that the fluorine-substituted analog was more lipophilic, but its translocation across the plasma membrane was slower by at least one order of magnitude than that of the parent hydrogenated anion.
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Affiliation(s)
- M Kürschner
- Lehrstuhl für Biotechnologie, Biozentrum and Institut für Anorganische Chemie der Universität Würzburg, D-97074 Würzburg, Germany
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