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Behzadifar S, Barras A, Plaisance V, Pawlowski V, Szunerits S, Abderrahmani A, Boukherroub R. Polymer-Based Nanostructures for Pancreatic Beta-Cell Imaging and Non-Invasive Treatment of Diabetes. Pharmaceutics 2023; 15:pharmaceutics15041215. [PMID: 37111699 PMCID: PMC10143373 DOI: 10.3390/pharmaceutics15041215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/01/2023] [Accepted: 04/07/2023] [Indexed: 04/29/2023] Open
Abstract
Diabetes poses major economic, social, and public health challenges in all countries worldwide. Besides cardiovascular disease and microangiopathy, diabetes is a leading cause of foot ulcers and lower limb amputations. With the continued rise of diabetes prevalence, it is expected that the future burden of diabetes complications, early mortality, and disabilities will increase. The diabetes epidemic is partly caused by the current lack of clinical imaging diagnostic tools, the timely monitoring of insulin secretion and insulin-expressing cell mass (beta (β)-cells), and the lack of patients' adherence to treatment, because some drugs are not tolerated or invasively administrated. In addition to this, there is a lack of efficient topical treatment capable of stopping the progression of disabilities, in particular for treating foot ulcers. In this context, polymer-based nanostructures garnered significant interest due to their tunable physicochemical characteristics, rich diversity, and biocompatibility. This review article emphasizes the last advances and discusses the prospects in the use of polymeric materials as nanocarriers for β-cell imaging and non-invasive drug delivery of insulin and antidiabetic drugs in the management of blood glucose and foot ulcers.
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Affiliation(s)
- Shakila Behzadifar
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Alexandre Barras
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Valérie Plaisance
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Valérie Pawlowski
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Sabine Szunerits
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Amar Abderrahmani
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Rabah Boukherroub
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
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2
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Neo CWY, Ciaramicoli LM, Soetedjo AAP, Teo AKK, Kang NY. A new perspective of probe development for imaging pancreatic beta cell in vivo. Semin Cell Dev Biol 2020; 103:3-13. [PMID: 32057664 DOI: 10.1016/j.semcdb.2020.01.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 01/20/2020] [Accepted: 01/28/2020] [Indexed: 12/23/2022]
Abstract
Beta cells assume a fundamental role in maintaining blood glucose homeostasis through the secretion of insulin, which is contingent on both beta cell mass and function, in response to elevated blood glucose levels or secretagogues. For this reason, evaluating beta cell mass and function, as well as scrutinizing how they change over time in a diabetic state, are essential prerequisites in elucidating diabetes pathophysiology. Current clinical methods to measure human beta cell mass and/or function are largely lacking, indirect and sub-optimal, highlighting the continued need for noninvasive in vivo beta cell imaging technologies such as optical imaging techniques. While numerous probes have been developed and evaluated for their specificity to beta cells, most of them are more suited to visualize beta cell mass rather than function. In this review, we highlight the distinction between beta cell mass and function, and the importance of developing more probes to measure beta cell function. Additionally, we also explore various existing probes that can be employed to measure beta cell mass and function in vivo, as well as the caveats in probe development for in vivo beta cell imaging.
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Affiliation(s)
- Claire Wen Ying Neo
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), A*STAR, Singapore, 138673, Singapore; Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117596, Singapore
| | - Larissa Miasiro Ciaramicoli
- Department of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Andreas Alvin Purnomo Soetedjo
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), A*STAR, Singapore, 138673, Singapore
| | - Adrian Kee Keong Teo
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), A*STAR, Singapore, 138673, Singapore; Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117596, Singapore.
| | - Nam-Young Kang
- Department of Creative IT Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Namgu, C5 Building, Room 203, Pohang, Kyungbuk, 37673, Republic of Korea.
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3
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Michelotti FC, Bowden G, Küppers A, Joosten L, Maczewsky J, Nischwitz V, Drews G, Maurer A, Gotthardt M, Schmid AM, Pichler BJ. PET/MRI enables simultaneous in vivo quantification of β-cell mass and function. Am J Cancer Res 2020; 10:398-410. [PMID: 31903128 PMCID: PMC6929626 DOI: 10.7150/thno.33410] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 10/02/2019] [Indexed: 12/14/2022] Open
Abstract
Non-invasive imaging of β-cells represents a desirable preclinical and clinical tool to monitor the change of β-cell mass and the loss of function during pre-diabetic stages. Although it is widely accepted that manganese (Mn) ions are actively gated by voltage-dependent calcium channels (VDCC) in response to glucose metabolism, little is known on its specificity in vivo for quantification of islet β-cell function using Mn and magnetic resonance imaging (MRI). On the other hand, glucagon-like-peptide-1 receptor (GLP-1R) represents a validated target for the estimation of β-cell mass using radiolabeled exendin-4 (Ex4) and positron emission tomography (PET). However, a multiparametric imaging workflow revealing β-cell mass and function quantitatively is still missing. Methods: We developed a simultaneous PET/MRI protocol to comprehensively quantify in vivo changes in β-cell mass and function by targeting, respectively, GLP-1R and VDCC coupled with insulin secretion. Differences in the spatial distribution of Mn and radiolabeled Ex4 were monitored overtime in native and transgenic pancreata, characterized by spontaneous pancreatic neuroendocrine tumor development. Follow-up with mass spectrometry imaging (MSI) and autoradiography allowed the ex vivo validation of the specificity of Mn and PET tracer uptake and the detection of endogenous biometals, such as calcium and zinc, throughout the endocrine and exocrine pancreas. Results: Our in vivo data based on a volumetric PET/MRI readout for native pancreata and insulinomas connects uptake of Mn measured at early imaging time points to high non-specific binding by the exocrine tissue, while specific retention was only found 24 h post injection. These results are supported by cross-validation of the spatial distribution of exogenous 55Mn and endogenous 44Ca and 64Zn as well with the specific internalization of the radiolabeled peptide targeting GLP-1R. Conclusion: Simultaneous PET/MR imaging of the pancreas enabled the comprehensive in vivo quantification of β-cell function and mass using Mn and radiolabeled Ex4. Most important, our data revealed that only late time-point measurements reflect the Mn uptake in the islet β-cells, while early time points detect non-specific accumulation of Mn in the exocrine pancreas.
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Joosten L, Brom M, Peeters H, Heskamp S, Béhé M, Boerman O, Gotthardt M. Enhanced Specific Activity by Multichelation of Exendin-3 Leads To Improved Image Quality and In Vivo Beta Cell Imaging. Mol Pharm 2017; 15:486-494. [PMID: 29226686 PMCID: PMC6150723 DOI: 10.1021/acs.molpharmaceut.7b00853] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Glucagon-like peptide-1 receptor (GLP-1R) targeting using radiolabeled exendin is a promising approach to noninvasively visualize and determine beta cell mass (BCM), which could help to unravel the pathophysiology of diabetes. However, saturation of the GLP-1R on beta cells occurs at low peptide doses, since the number of receptors expressed under physiological conditions is low. Therefore, tracers with high specific activities are required to sensitively image small variations in BCM. Here, we describe a novel exendin-3-based radiotracer with multiple chelators and determine its potential for in vivo beta cell imaging. Exendin-3 was modified by adding six lysine residues C-terminally conjugated with one, two, or six DTPA moieties. All compounds were labeled with 111In and their GLP-1R affinity was determined in vitro using GLP-1R expressing cells. The in vivo behavior of the 111In-labeled tracers was examined in BALB/c nude mice with a subcutaneous GLP-1R expressing tumor (INS-1). Brown Norway rats were used for SPECT visualization of the pancreatic BCM. Addition of six lysine and six DTPA residues (hexendin(40-45)) resulted in a 7-fold increase in specific activity (from 0.73 GBq/nmol to 5.54 GBq/nmol). IC50 values varied between 5.2 and 69.5 nM. All compounds with two or six lysine and DTPA residues had a significantly lower receptor affinity than [Lys40(DTPA)]exendin-3 (4.4 nM, p < 0.05). The biodistribution in mice revealed no significant decrease in pancreatic uptake after addition of six lysine and DTPA molecules. Hexendin(40-45) showed a 6-fold increase in absolute 111In uptake in the pancreas of Brown Norway rats compared to [Lys40(DTPA)]exendin-3 (182.7 ± 42.3 kBq vs 28.8 ± 6.0 kBq, p < 0.001). Visualization of the pancreas on SPECT was improved using hexendin(40-45), due to the higher count rate, achieved at the same peptide dose. In conclusion, hexendin(40-45) showed an improved visualization of the pancreas with SPECT. This tracer holds promise to sensitively and specifically detect small variations in BCM.
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Affiliation(s)
- Lieke Joosten
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center , PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Maarten Brom
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center , PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Hanneke Peeters
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center , PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Sandra Heskamp
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center , PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Martin Béhé
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institut , 5232 Villigen, Switzerland
| | - Otto Boerman
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center , PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Martin Gotthardt
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center , PO Box 9101, 6500 HB Nijmegen, The Netherlands
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5
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Boehmer BH, Limesand SW, Rozance PJ. The impact of IUGR on pancreatic islet development and β-cell function. J Endocrinol 2017; 235:R63-R76. [PMID: 28808079 PMCID: PMC5808569 DOI: 10.1530/joe-17-0076] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 08/10/2017] [Indexed: 12/14/2022]
Abstract
Placental insufficiency is a primary cause of intrauterine growth restriction (IUGR). IUGR increases the risk of developing type 2 diabetes mellitus (T2DM) throughout life, which indicates that insults from placental insufficiency impair β-cell development during the perinatal period because β-cells have a central role in the regulation of glucose tolerance. The severely IUGR fetal pancreas is characterized by smaller islets, less β-cells, and lower insulin secretion. Because of the important associations among impaired islet growth, β-cell dysfunction, impaired fetal growth, and the propensity for T2DM, significant progress has been made in understanding the pathophysiology of IUGR and programing events in the fetal endocrine pancreas. Animal models of IUGR replicate many of the observations in severe cases of human IUGR and allow us to refine our understanding of the pathophysiology of developmental and functional defects in islet from IUGR fetuses. Almost all models demonstrate a phenotype of progressive loss of β-cell mass and impaired β-cell function. This review will first provide evidence of impaired human islet development and β-cell function associated with IUGR and the impact on glucose homeostasis including the development of glucose intolerance and diabetes in adulthood. We then discuss evidence for the mechanisms regulating β-cell mass and insulin secretion in the IUGR fetus, including the role of hypoxia, catecholamines, nutrients, growth factors, and pancreatic vascularity. We focus on recent evidence from experimental interventions in established models of IUGR to understand better the pathophysiological mechanisms linking placental insufficiency with impaired islet development and β-cell function.
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Affiliation(s)
- Brit H Boehmer
- Department of PediatricsPerinatal Research Center, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Sean W Limesand
- School of Animal and Comparative Biomedical SciencesUniversity of Arizona, Tucson, Arizona, USA
| | - Paul J Rozance
- Department of PediatricsPerinatal Research Center, University of Colorado School of Medicine, Aurora, Colorado, USA
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6
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Hernandez R, Graves SA, Gregg T, VanDeusen HR, Fenske RJ, Wienkes HN, England CG, Valdovinos HF, Jeffery JJ, Barnhart TE, Severin GW, Nickles RJ, Kimple ME, Merrins MJ, Cai W. Radiomanganese PET Detects Changes in Functional β-Cell Mass in Mouse Models of Diabetes. Diabetes 2017; 66:2163-2174. [PMID: 28515126 PMCID: PMC5521871 DOI: 10.2337/db16-1285] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 05/12/2017] [Indexed: 01/09/2023]
Abstract
The noninvasive measurement of functional β-cell mass would be clinically valuable for monitoring the progression of type 1 and type 2 diabetes as well as the viability of transplanted insulin-producing cells. Although previous work using MRI has shown promise for functional β-cell mass determination through voltage-dependent Ca2+ channel (VDCC)-mediated internalization of Mn2+, the clinical utility of this technique is limited by the cytotoxic levels of the Mn2+ contrast agent. Here, we show that positron emission tomography (PET) is advantageous for determining functional β-cell mass using 52Mn2+ (t1/2: 5.6 days). We investigated the whole-body distribution of 52Mn2+ in healthy adult mice by dynamic and static PET imaging. Pancreatic VDCC uptake of 52Mn2+ was successfully manipulated pharmacologically in vitro and in vivo using glucose, nifedipine (VDCC blocker), the sulfonylureas tolbutamide and glibenclamide (KATP channel blockers), and diazoxide (KATP channel opener). In a mouse model of streptozotocin-induced type 1 diabetes, 52Mn2+ uptake in the pancreas was distinguished from healthy controls in parallel with classic histological quantification of β-cell mass from pancreatic sections. 52Mn2+-PET also reported the expected increase in functional β-cell mass in the ob/ob model of pretype 2 diabetes, a result corroborated by histological β-cell mass measurements and live-cell imaging of β-cell Ca2+ oscillations. These results indicate that 52Mn2+-PET is a sensitive new tool for the noninvasive assessment of functional β-cell mass.
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Affiliation(s)
- Reinier Hernandez
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI
| | - Stephen A Graves
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI
| | - Trillian Gregg
- Department of Medicine, Division of Endocrinology, Diabetes & Metabolism, University of Wisconsin-Madison, Madison, WI
- Program in Biophysics, University of Wisconsin-Madison, Madison, WI
| | - Halena R VanDeusen
- Department of Medicine, Division of Endocrinology, Diabetes & Metabolism, University of Wisconsin-Madison, Madison, WI
| | - Rachel J Fenske
- Department of Medicine, Division of Endocrinology, Diabetes & Metabolism, University of Wisconsin-Madison, Madison, WI
| | - Haley N Wienkes
- Department of Medicine, Division of Endocrinology, Diabetes & Metabolism, University of Wisconsin-Madison, Madison, WI
| | | | | | - Justin J Jeffery
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI
| | - Todd E Barnhart
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI
| | - Gregory W Severin
- Center for Nuclear Technologies, Technical University of Denmark, Roskilde, Denmark
- Department of Chemistry, Michigan State University, East Lansing, MI
| | - Robert J Nickles
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI
| | - Michelle E Kimple
- Department of Medicine, Division of Endocrinology, Diabetes & Metabolism, University of Wisconsin-Madison, Madison, WI
- William S. Middleton Memorial Veterans Hospital, Madison, WI
| | - Matthew J Merrins
- Department of Medicine, Division of Endocrinology, Diabetes & Metabolism, University of Wisconsin-Madison, Madison, WI
- William S. Middleton Memorial Veterans Hospital, Madison, WI
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI
| | - Weibo Cai
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI
- Department of Radiology, University of Wisconsin-Madison, Madison, WI
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7
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Graaf CD, Donnelly D, Wootten D, Lau J, Sexton PM, Miller LJ, Ahn JM, Liao J, Fletcher MM, Yang D, Brown AJH, Zhou C, Deng J, Wang MW. Glucagon-Like Peptide-1 and Its Class B G Protein-Coupled Receptors: A Long March to Therapeutic Successes. Pharmacol Rev 2017; 68:954-1013. [PMID: 27630114 PMCID: PMC5050443 DOI: 10.1124/pr.115.011395] [Citation(s) in RCA: 237] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The glucagon-like peptide (GLP)-1 receptor (GLP-1R) is a class B G protein-coupled receptor (GPCR) that mediates the action of GLP-1, a peptide hormone secreted from three major tissues in humans, enteroendocrine L cells in the distal intestine, α cells in the pancreas, and the central nervous system, which exerts important actions useful in the management of type 2 diabetes mellitus and obesity, including glucose homeostasis and regulation of gastric motility and food intake. Peptidic analogs of GLP-1 have been successfully developed with enhanced bioavailability and pharmacological activity. Physiologic and biochemical studies with truncated, chimeric, and mutated peptides and GLP-1R variants, together with ligand-bound crystal structures of the extracellular domain and the first three-dimensional structures of the 7-helical transmembrane domain of class B GPCRs, have provided the basis for a two-domain-binding mechanism of GLP-1 with its cognate receptor. Although efforts in discovering therapeutically viable nonpeptidic GLP-1R agonists have been hampered, small-molecule modulators offer complementary chemical tools to peptide analogs to investigate ligand-directed biased cellular signaling of GLP-1R. The integrated pharmacological and structural information of different GLP-1 analogs and homologous receptors give new insights into the molecular determinants of GLP-1R ligand selectivity and functional activity, thereby providing novel opportunities in the design and development of more efficacious agents to treat metabolic disorders.
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Affiliation(s)
- Chris de Graaf
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Dan Donnelly
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Denise Wootten
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Jesper Lau
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Patrick M Sexton
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Laurence J Miller
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Jung-Mo Ahn
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Jiayu Liao
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Madeleine M Fletcher
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Dehua Yang
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Alastair J H Brown
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Caihong Zhou
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Jiejie Deng
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Ming-Wei Wang
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
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8
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Jodal A, Schibli R, Béhé M. Targets and probes for non-invasive imaging of β-cells. Eur J Nucl Med Mol Imaging 2016; 44:712-727. [PMID: 28025655 PMCID: PMC5323463 DOI: 10.1007/s00259-016-3592-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 12/01/2016] [Indexed: 12/16/2022]
Abstract
β-cells, located in the islets of the pancreas, are responsible for production and secretion of insulin and play a crucial role in blood sugar regulation. Pathologic β-cells often cause serious medical conditions affecting blood glucose level, which severely impact life quality and are life-threatening if untreated. With 347 million patients, diabetes is one of the most prevalent diseases, and will continue to be one of the largest socioeconomic challenges in the future. The diagnosis still relies mainly on indirect methods like blood sugar measurements. A non-invasive diagnostic imaging modality would allow direct evaluation of β-cell mass and would be a huge step towards personalized medicine. Hyperinsulinism is another serious condition caused by β-cells that excessively secrete insulin, like for instance β-cell hyperplasia and insulinomas. Treatment options with drugs are normally not curative, whereas curative procedures usually consist of the resection of affected regions for which, however, an exact localization of the foci is necessary. In this review, we describe potential tracers under development for targeting β-cells with focus on radiotracers for PET and SPECT imaging, which allow the non-invasive visualization of β-cells. We discuss either the advantages or limitations for the various tracers and modalities. This article concludes with an outlook on future developments and discuss the potential of new imaging probes including dual probes that utilize functionalities for both a radioactive and optical moiety as well as for theranostic applications.
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Affiliation(s)
- Andreas Jodal
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Roger Schibli
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institut, 5232, Villigen, Switzerland.,Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Martin Béhé
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institut, 5232, Villigen, Switzerland.
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9
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Berchtold LA, Prause M, Størling J, Mandrup-Poulsen T. Cytokines and Pancreatic β-Cell Apoptosis. Adv Clin Chem 2016; 75:99-158. [PMID: 27346618 DOI: 10.1016/bs.acc.2016.02.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The discovery 30 years ago that inflammatory cytokines cause a concentration, activity, and time-dependent bimodal response in pancreatic β-cell function and viability has been a game-changer in the fields of research directed at understanding inflammatory regulation of β-cell function and survival and the causes of β-cell failure and destruction in diabetes. Having until then been confined to the use of pathophysiologically irrelevant β-cell toxic chemicals as a model of β-cell death, researchers could now mimic endocrine and paracrine effects of the cytokine response in vitro by titrating concentrations in the low to the high picomolar-femtomolar range and vary exposure time for up to 14-16h to reproduce the acute regulatory effects of systemic inflammation on β-cell secretory responses, with a shift to inhibition at high picomolar concentrations or more than 16h of exposure to illustrate adverse effects of local, chronic islet inflammation. Since then, numerous studies have clarified how these bimodal responses depend on discrete signaling pathways. Most interest has been devoted to the proapoptotic response dependent upon mainly nuclear factor κ B and mitogen-activated protein kinase activation, leading to gene expressional changes, endoplasmic reticulum stress, and triggering of mitochondrial dysfunction. Preclinical studies have shown preventive effects of cytokine antagonism in animal models of diabetes, and clinical trials demonstrating proof of concept are emerging. The full clinical potential of anticytokine therapies has yet to be shown by testing the incremental effects of appropriate dosing, timing, and combinations of treatments. Due to the considerable translational importance of enhancing the precision, specificity, and safety of antiinflammatory treatments of diabetes, we review here the cellular, preclinical, and clinical evidence of which of the death pathways recently proposed in the Nomenclature Committee on Cell Death 2012 Recommendations are activated by inflammatory cytokines in the pancreatic β-cell to guide the identification of antidiabetic targets. Although there are still scarce human data, the cellular and preclinical studies point to the caspase-dependent intrinsic apoptosis pathway as the prime effector of inflammatory β-cell apoptosis.
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Affiliation(s)
| | - M Prause
- University of Copenhagen, Copenhagen, Denmark
| | - J Størling
- Copenhagen Diabetes Research Center, Beta Cell Biology Group, Copenhagen University Hospital Herlev, Herlev, Denmark
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10
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Burtea C, Laurent S, Crombez D, Delcambre S, Sermeus C, Millard I, Rorive S, Flamez D, Beckers MC, Salmon I, Vander Elst L, Eizirik DL, Muller RN. Development of a peptide-functionalized imaging nanoprobe for the targeting of (FXYD2)γa as a highly specific biomarker of pancreatic beta cells. CONTRAST MEDIA & MOLECULAR IMAGING 2015; 10:398-412. [PMID: 25930968 DOI: 10.1002/cmmi.1641] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Revised: 02/06/2015] [Accepted: 02/17/2015] [Indexed: 01/15/2023]
Abstract
Diabetes is characterized by a progressive decline of the pancreatic beta cell mass (BCM), which is responsible for insufficient insulin secretion and hyperglycaemia. There are currently no reliable methods to measure non-invasively the BCM in diabetic patients. Our work describes a phage display-derived peptide (P88) that is highly specific to (FXYD2)γa expressed by human beta cells and is proposed as a molecular vector for the development of functionalized imaging probes. P88 does not bind to the exocrine pancreas and is able to detect down to ~156 human pancreatic islets/mm(3) in vitro after conjugation to ultra-small particles of iron oxide (USPIO), as proven by the R2 measured on MR images. For in vivo evaluation, MRI studies were carried out on nude mice bearing Capan-2 tumours that also express (FXYD2)γa. A strong negative contrast was obtained subsequent to the injection of USPIO-P88, but not in negative controls. On human histological sections, USPIO-P88 seems to be specific to pancreatic beta cells, but not to duodenum, stomach or kidney tissues. USPIO-P88 thus represents a novel and promising tool for monitoring pancreatic BCM in diabetic patients. The quantitative correlation between BCM and R2 remains to be demonstrated in vivo, but the T2 mapping and the black pixel estimation after USPIO-P88 injection could provide important information for the future pancreatic BCM evaluation by MRI.
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Affiliation(s)
- Carmen Burtea
- Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons, Avenue Maistriau 19, Mendeleev Building, B-7000, Mons, Belgium
| | - Sophie Laurent
- Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons, Avenue Maistriau 19, Mendeleev Building, B-7000, Mons, Belgium
| | - Deborah Crombez
- Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons, Avenue Maistriau 19, Mendeleev Building, B-7000, Mons, Belgium
| | - Sébastien Delcambre
- Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons, Avenue Maistriau 19, Mendeleev Building, B-7000, Mons, Belgium
| | - Corine Sermeus
- Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons, Avenue Maistriau 19, Mendeleev Building, B-7000, Mons, Belgium
| | - Isabelle Millard
- Center for Diabetes Research, Université Libre de Bruxelles, Route de Lennik 808, 1070, Brussels, Belgium
| | - Sandrine Rorive
- Department of Pathology, Erasme Hospital, Université Libre de Bruxelles, Route de Lennik 808, 1070, Brussels, Belgium.,DIAPath, Center for Microscopy and Molecular Imaging, 8 rue Adrienne Bolland, 6041, Gosselies, Belgium
| | - Daisy Flamez
- Center for Diabetes Research, Université Libre de Bruxelles, Route de Lennik 808, 1070, Brussels, Belgium
| | - Marie-Claire Beckers
- Eurogentec S.A., Liège Science Park, Rue du Bois Saint-Jean 5, B-4102, Seraing, Belgium
| | - Isabelle Salmon
- Department of Pathology, Erasme Hospital, Université Libre de Bruxelles, Route de Lennik 808, 1070, Brussels, Belgium.,DIAPath, Center for Microscopy and Molecular Imaging, 8 rue Adrienne Bolland, 6041, Gosselies, Belgium
| | - Luce Vander Elst
- Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons, Avenue Maistriau 19, Mendeleev Building, B-7000, Mons, Belgium
| | - Decio L Eizirik
- Center for Diabetes Research, Université Libre de Bruxelles, Route de Lennik 808, 1070, Brussels, Belgium
| | - Robert N Muller
- Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons, Avenue Maistriau 19, Mendeleev Building, B-7000, Mons, Belgium.,Center for Microscopy and Molecular Imaging, 8 rue Adrienne Bolland, 6041, Gosselies, Belgium
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11
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Manandhar B, Ahn JM. Glucagon-like peptide-1 (GLP-1) analogs: recent advances, new possibilities, and therapeutic implications. J Med Chem 2014; 58:1020-37. [PMID: 25349901 PMCID: PMC4329993 DOI: 10.1021/jm500810s] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
![]()
Glucagon-like peptide-1 (GLP-1) is
an incretin that plays important
physiological roles in glucose homeostasis. Produced from intestine
upon food intake, it stimulates insulin secretion and keeps pancreatic
β-cells healthy and proliferating. Because of these beneficial
effects, it has attracted a great deal of attention in the past decade,
and an entirely new line of diabetic therapeutics has emerged based
on the peptide. In addition to the therapeutic applications, GLP-1
analogs have demonstrated a potential in molecular imaging of pancreatic β-cells;
this may be useful in early detection of the disease and evaluation
of therapeutic interventions, including islet transplantation. In
this Perspective, we focus on GLP-1 analogs for their studies on improvement
of biological activities, enhancement of metabolic stability, investigation
of receptor interaction, and visualization of the pancreatic islets.
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Affiliation(s)
- Bikash Manandhar
- Department of Chemistry, University of Texas at Dallas , Richardson, Texas 75080, United States
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12
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Balla DZ, Gottschalk S, Shajan G, Ueberberg S, Schneider S, Hardtke-Wolenski M, Jaeckel E, Hoerr V, Faber C, Scheffler K, Pohmann R, Engelmann J. In vivo visualization of single native pancreatic islets in the mouse. CONTRAST MEDIA & MOLECULAR IMAGING 2014; 8:495-504. [PMID: 24375905 DOI: 10.1002/cmmi.1580] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 09/22/2013] [Accepted: 10/14/2013] [Indexed: 11/12/2022]
Abstract
The purpose of this study was to investigate the potential of a novel targeted contrast agent (CA) for the in vivo visualization of single native pancreatic islets, the sites of insulin production, in the pancreas of mice using magnetic resonance imaging (MRI). The CA for intravenous administration was composed of the β-cell-specific single-chain antibody fragment, SCA B1, and ferromagnetic carbon-coated cobalt nanoparticles. MRI experiments were performed at 7, 9.4 and 16.4 T in excised organs (pancreas, liver, kidney, spleen), at 7 T in mice fixed in formalin and at 9.4 and 16.4 T in living mice. Image contrast in untreated control animals was compared with images from mice treated with unspecific and specific CA. For the validation of MRI results, selected pancreases were subjected to immunohistochemical staining and numerical contrast simulations were performed. Ex vivo results and the outcome of immunohistochemistry suggest that islets are marked only by the CA containing SCA B1. Strong accumulation of particles was found also in other investigated organs owing to the uptake by the reticuloendothelial system, but the contrast in the MR images is clearly distinguishable from the islet specific contrast in pancreases and numerical predictions. In vivo experiments based on averaged dynamic sampling with 66 × 66 × 100 µm³ and triggered acquisition with 90 × 90 × 200 µm³ nominal resolution resulted in similar particle contrast to in in vitro measurements. The newly developed CA and MRI strategies have the potential to be used for studying mouse diabetes models by visualizing single native pancreatic islets.
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Affiliation(s)
- Dávid Z Balla
- High-Field Magnetic Resonance Centre, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany
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13
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Zacharovová K, Berková Z, Jirák D, Herynek V, Vancová M, Dovolilová E, Saudek F. Processing of superparamagnetic iron contrast agent ferucarbotran in transplanted pancreatic islets. CONTRAST MEDIA & MOLECULAR IMAGING 2013; 7:485-93. [PMID: 22991314 DOI: 10.1002/cmmi.1477] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Labeling of pancreatic islets with superparamagnetic iron oxide (SPIO) nanoparticles enables their post-transplant monitoring by magnetic resonance imaging (MRI). Although the nanoparticles are incorporated into islet cells in culture, little is known about their fate in vivo. We studied the morphology of labeled islets after transplantation, aiming to identify the MRI contrast particles and their relationship to transplantation outcomes. Rat islets labeled with the ferucarbotran were transplanted into the liver or under the kidney capsule of syngeneic and allogeneic rats. After in vivo MRI, morphology was studied by light, fluorescence and transmission electron microscopy. Morphology of syngeneic islets transplanted beneath the kidney capsule vs into the liver was similar. Iron particles were almost completely eliminated from the endocrine cells and remained located in host-derived macrophages surrounding the vital islets for the entire study period. In the allogeneic model, islets lost their function and were completely rejected within nine days following transplantation in both transplant models. However, intercellular transport of the SPIO particles and subsequent MRI findings was different in the liver and kidney. In the liver, the decreasing number of islet-related MRI spots corresponded with clearance of iron particles in rejected islets; in contrast, with renal transplants extensive iron deposits with a high effect on MRI signal persisted in phagocytic cells beneath the capsule. We conclude that MRI detection of the iron contrast agent correlates with islet survival and function in islet transplantation into the liver, while it does not correlate in the case of transplantation beneath the renal capsule.
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Affiliation(s)
- Klára Zacharovová
- Laboratory of Langerhans Islets, Centre of Experimental Medicine, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
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14
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15
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Ex vivo imaging of pancreatic beta cells using a radiolabeled GLP-1 receptor agonist. Mol Imaging Biol 2012; 14:79-87. [PMID: 21394533 DOI: 10.1007/s11307-011-0481-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE The purpose of this study was to evaluate the binding specificity of the radiolabeled glucagon-like peptide 1 receptor (GLP-1R) agonist (Lys⁴⁰(DOTA)NH₂)Exendin-4 in the pancreas using a combination of ex vivo autoradiography and immunohistochemistry. PROCEDURES Sprague-Dawley rats were administered [⁶⁴Cu](Lys⁴⁰(DOTA)NH₂)Exendin-4 i.v. with or without unlabeled Exendin (9-39) to determine binding specificity. Similar experiments were performed using Zucker diabetic fatty (ZDF) and Zucker lean (ZLC) rats. Animals were euthanized and the pancreas was extracted, immediately frozen, and sectioned. The sections were apposed to phosphor imaging plates, scanned, and immunostained for insulin. RESULTS Co-registration of the autoradiographic and immunohistochemical images revealed that [⁶⁴Cu] (Lys⁴⁰(DOTA)NH₂)Exendin-4 specific binding was restricted to islet cells. This binding was blocked by the co-administration of Exendin(9-39) indicating that the radiotracer uptake is mediated by GLP-1R. Uptake of [⁶⁴Cu](Lys⁴⁰(DOTA)NH₂)Exendin-4 was greatly decreased in the pancreas of ZDF rats. CONCLUSIONS Ex vivo autoradiography results using [⁶⁴Cu](Lys⁴⁰(DOTA)NH₂)Exendin-4 suggest that GLP-1R agonists based on Exendin-4 are attractive PET ligands for the in vivo determination of β-cell mass.
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16
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Arifin D, Manek S, Call E, Arepally A, Bulte J. Microcapsules with intrinsic barium radiopacity for immunoprotection and X-ray/CT imaging of pancreatic islet cells. Biomaterials 2012; 33:4681-9. [PMID: 22444642 PMCID: PMC3331919 DOI: 10.1016/j.biomaterials.2012.03.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 03/03/2012] [Indexed: 01/23/2023]
Abstract
Microencapsulation is a commonly used technique for immunoprotection of engrafted therapeutic cells. We investigated a library of capsule formulations to determine the most optimal formulation for pancreatic beta islet cell transplantation, using barium as the gelating ion and clinical-grade protamine sulfate (PS) as a new cationic capsule cross-linker. Barium-gelated alginate/PS/alginate microcapsules (APSA, diameter = 444 ± 21 μm) proved to be mechanically stronger and supported a higher cell viability as compared to conventional alginate/poly-l-lysine/alginate (APLLA) capsules. Human pancreatic islets encapsulated inside APSA capsules, gelated with 20 mm barium as optimal concentration, exhibited a sustained morphological integrity, viability, and functionality for at least 3-4 weeks in vitro, with secreted human C-peptide levels of 0.2-160 pg/ml/islet. Unlike APLLA capsules that are gelled with calcium, barium-APSA capsules are intrinsically radiopaque and, when engrafted into mice, could be readily imaged in vivo with micro-computed tomography (CT). Without the need of adding contrast agents, these capsules offer a clinically applicable alternative for simultaneous immunoprotection and real-time, non-invasive X-ray/CT monitoring of engrafted cells during and after in vivo administration.
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Affiliation(s)
- D.R. Arifin
- Russell H. Morgan Dept. of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - S. Manek
- Russell H. Morgan Dept. of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Dept. of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - E. Call
- Russell H. Morgan Dept. of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - A. Arepally
- Russell H. Morgan Dept. of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - J.W.M. Bulte
- Russell H. Morgan Dept. of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Dept. of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Dept. of Chemical & Biomolecular Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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17
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Liu G, Dou S, Akalin A, Rusckowski M, Streeter PR, Shultz LD, Greiner DL. Pretargeting vs. direct targeting of human betalox5 islet cells subcutaneously implanted in mice using an anti-human islet cell antibody. Nucl Med Biol 2012; 39:645-51. [PMID: 22316614 DOI: 10.1016/j.nucmedbio.2011.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 11/30/2011] [Accepted: 12/07/2011] [Indexed: 11/25/2022]
Abstract
INTRODUCTION We previously demonstrated MORF/cMORF pretargeting of human islets and betalox 5 cells (a human beta cell line) transplanted subcutaneously in mice with the anti-human islet antibody, HPi1. We now compare pretargeting with direct targeting in the beta cell transplant model to evaluate the degree to which target/non-target (T/NT) ratios may be improved by pretargeting. METHODS Specific binding of an anti-human islet antibody HPi1 to the beta cells transplanted subcutaneously in mice was examined against a negative control antibody. We then compared pretargeting by MORF-HPi1 plus 111In-labeled cMORF to direct targeting by 111In-labeled HPi1. RESULTS HPi1 binding to betalox5 human cells in the transplant was shown by immunofluorescence. Normal organ 111In backgrounds by pretargeting were always lower, although target accumulations were similar. More importantly, the transplant to pancreas and liver ratios was, respectively, 26 and 10 by pretargeting as compared to 9 and 0.6 by direct targeting. CONCLUSIONS Pretargeting greatly improves the T/NT ratios, and based on the estimated endocrine to exocrine ratio within a pancreas, pretargeting may be approaching the sensitivity required for successful imaging of human islets within this organ.
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Affiliation(s)
- Guozheng Liu
- Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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Leibiger IB, Caicedo A, Berggren PO. Non-invasive in vivo imaging of pancreatic β-cell function and survival - a perspective. Acta Physiol (Oxf) 2012; 204:178-85. [PMID: 21477063 DOI: 10.1111/j.1748-1716.2011.02301.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
A major problem in medical research is to translate in vitro observations into the living organism. In this perspective, we discuss ongoing efforts to non-invasively image pancreatic islets/β-cells by techniques, such as magnetic resonance imaging and positron emission tomography, and present an experimental platform, which allows in vivo imaging of pancreatic β-cell mass and function longitudinally and at the single-cell level. Following transplantation of pancreatic islets into the anterior chamber of the eye of mice and rats, these islets are studied by functional microscopic imaging. This imaging platform can be utilized to address fundamental aspects of pancreatic islet cell biology in vivo in health and disease. These include the dynamics of pancreatic islet vascularization, islet cell innervation, signal-transduction, change in functional β-cell mass and immune responses. Moreover, we discuss the feasibility of studying human islet cell physiology and pathology in vivo as well as the potential of using the anterior chamber of the eye as a site for therapeutic transplantation in type 1 diabetes mellitus.
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Affiliation(s)
- I B Leibiger
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
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Kavishwar A, Medarova Z, Moore A. Unique sphingomyelin patches are targets of a beta-cell-specific antibody. J Lipid Res 2011; 52:1660-71. [PMID: 21747097 DOI: 10.1194/jlr.m017582] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
To devise successful imaging and therapeutic strategies, the identification of β-cell surface markers is one of the challenges in diabetes research that has to be resolved. We previously showed that IC2, a rat monoclonal IgM antibody, can be used for ex vivo determination of β-cell mass by imaging. Further progress toward the development of an antibody-based imaging agent was hampered by the lack of knowledge regarding the nature and composition of the IC2 antigen. Here, we show a series of systematic experiments involving classical lipid extraction and chromatography techniques combined with immunochemistry, which led to the identification of sphingomyelin as the target antigen assembled in the form of patches on the β-cell surface. Our findings were verified by modulating SM by enzymatic cleavage, downregulation, upregulation, and perturbation of membrane SM and observation of corresponding changes in IC2 binding. Cholesterol participates in stabilization of these patches, as its removal results in loss of IC2 binding. We believe that these findings have implications for identifying future ligands for the proposed antigen for imaging purposes as well as for potential therapy, as sphingomyelin has been shown to play a role in the apoptotic cascade in pancreatic β cells.
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Affiliation(s)
- Amol Kavishwar
- Molecular Imaging Laboratory, MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA
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Arifin DR, Long CM, Gilad AA, Alric C, Roux S, Tillement O, Link TW, Arepally A, Bulte JWM. Trimodal gadolinium-gold microcapsules containing pancreatic islet cells restore normoglycemia in diabetic mice and can be tracked by using US, CT, and positive-contrast MR imaging. Radiology 2011; 260:790-8. [PMID: 21734156 DOI: 10.1148/radiol.11101608] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To develop microcapsules that immunoprotect pancreatic islet cells for treatment of type I diabetes and enable multimodal cellular imaging of transplanted islet cells. MATERIALS AND METHODS All animal experiments were approved by the institutional animal care and use committee. Gold nanoparticles functionalized with DTDTPA (dithiolated diethylenetriaminepentaacetic acid):gadolinium chelates (GG) were coencapsulated with pancreatic islet cells by using protamine sulfate as a clinical-grade alginate cross linker. Conventional poly-l-lysine-cross-linked microcapsules and unencapsulated islets were included as controls. The viability and glucose responsiveness of islet cells were assessed in vitro, and in vivo insulin (C-peptide) secretion was monitored for 6 weeks in (streptozotocin-induced) diabetic mice with (n = 7) or without (n = 8) intraabdominally engrafted islet cells. Five nondiabetic mice were included as controls. Differences between samples were calculated by using a nonparametric Wilcoxon Mann-Whitney method. To adjust for multiple comparisons, a significance level of P < .01 was chosen. Generalized estimating equations were used to model cell function over time. Three mice with engrafted capsules were imaged in vivo with high-field-strength (9.4-T) magnetic resonance (MR) imaging, micro-computed tomography (CT), and 40-MHz ultrasonography (US). RESULTS Encapsulated human pancreatic islets were functional in vitro for at least 2 weeks after encapsulation. Blood glucose levels in the diabetic mice transplanted with GG-labeled encapsulated mouse βTC6 insulinoma cells returned to normal within 1 week after transplantation, and normoglycemia was sustained for at least 6 weeks without the use of immunosuppressive drugs. GG microcapsules could be readily visualized with positive-contrast high-field-strength MR imaging, micro-CT, and US both in vitro and in vivo. CONCLUSION Cell encapsulation with GG provides a means of trimodal noninvasive tracking of engrafted cells.
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Affiliation(s)
- Dian R Arifin
- Division of MR Research, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 720 Rutland Ave, 217 Traylor, Baltimore, MD 21205, USA
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Liu G, Dou S, Cheng D, Leif J, Rusckowski M, Streeter PR, Shultz LD, Hnatowich DJ, Greiner DL. Human islet cell MORF/cMORF pretargeting in a xenogeneic murine transplant model. Mol Pharm 2011; 8:767-73. [PMID: 21361360 DOI: 10.1021/mp100382m] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Noninvasive measurement of human islet cell mass in pancreas or following islet transplantation by nuclear imaging has yet to be achieved. It has been shown using mouse tumor models that pretargeting imaging strategies are sensitive and can greatly increase target to nontarget signal ratios. The objective now is to demonstrate the specific pretargeting of human islet cells in mice. Our pretargeting strategy uses an anti-human islet cell antibody HPi1, conjugated to a phosphorodiamidate morpholino oligomer (MORF) that binds specifically to a (99m)Tc labeled complementary MORF (cMORF). Sensitivity and specificity of the pretargeting were first validated in culture using a human beta cell line (betalox5) and a negative control human cell line (HEK293). Pretargeting was then used to target and visualize these two cell lines and human islets transplanted subcutaneously in NOD-scid IL2rγ(null) mice. In culture, (99m)Tc accumulation on the betalox5 cells pretargeted by MORF-HPi1 was 100-fold higher than on untreated betalox5 cells or following treatment with native HPi1 and much higher than on the MORF-HPi1 pretargeted control HEK293 cells. Small animal imaging readily localized the transplanted betalox5 cells and human islets, but not the HEK293 cells. Ex vivo counting demonstrated 3-fold higher (99m)Tc accumulation in the transplanted betalox5 cells and human islets than in the control HEK293 cells. The target accumulation was also shown to increase linearly with increased numbers of the implanted betalox5 cells. These results demonstrate specific binding of radioactivity and successful imaging of human betalox5 cells and human islets transplanted in mice. Thus MORF/cMORF pretargeting may be useful to measure noninvasively human islet cell mass within the pancreas or following islet transplantation.
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Affiliation(s)
- Guozheng Liu
- Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA.
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Affiliation(s)
- Guy M Bormans
- Laboratory for Radiopharmaceutical, Sciences, KU Leuven, Leuven, Belgium.
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Nagata M, Kagawa T, Koutou D, Matsushita T, Yamazaki Y, Murase K. Measurement of manganese content in various organs in rats with or without glucose stimulation. Radiol Phys Technol 2010; 4:7-12. [PMID: 20820965 DOI: 10.1007/s12194-010-0098-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 07/15/2010] [Accepted: 07/20/2010] [Indexed: 12/27/2022]
Abstract
Our purpose in this study was to assess the manganese (Mn) content in various organs in rats with or without glucose stimulation in vivo and in vitro by using magnetic resonance imaging (MRI) and polarized Zeeman atomic absorption spectrophotometry (PZAAS), respectively. MRI studies were performed in 12 rats using a 1.5-T MRI system. The rats were injected intravenously with saline (6 ml/kg) (saline-stimulated group, n = 6) or glucose (2.34 g/kg) (glucose-stimulated group, n = 6). Ten minutes after saline or glucose administration, MnCl₂ (0.02 mmol/kg) was injected intravenously, followed by 6 MRI studies at 8-min intervals. After the last MRI study, rats were killed, and the Mn concentrations in various organs were measured using PZAAS. There was a discrepancy between in vivo and in vitro measurements, which appeared to be due to the partial volume effect and/or the contribution of extracellular Mn. The Mn concentration in the pancreas, normalized to that in the liver in the glucose-stimulated group, increased significantly compared to that in the saline-stimulated group, suggesting that the influx of Mn into β cells in the pancreas increased in response to glucose stimulation. This study suggested that the measurement of the change in the Mn concentration due to glucose stimulation using PZAAS was effective for evaluating β-cell function in the pancreas.
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Affiliation(s)
- Mamoru Nagata
- Division of Medical Technology and Science, Department of Medical Physics and Engineering, Faculty of Health Science, Graduate School of Medicine, Osaka University, 1-7 Yamadaoka, Suita, Osaka, 565-0871, Japan
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Abstract
In both type 1 and type 2 diabetes mellitus, beta-cell mass (BCM), which exclusively produces insulin, is lost. Various therapeutic strategies are being developed that target BCM to restore its function by promoting beta-cell neogenesis and regeneration or by preventing its apoptosis. To this end, it is essential to identify biomarkers of BCM. Of the various imaging platforms, radionuclide-based imaging methods using radioligands that directly target BCM appear promising. In particular, the vesicular monoamine transporter type 2 (VMAT2), which is expressed almost exclusively by beta-cells and found in close association with insulin, can be noninvasively imaged with PET and (11)C-dihydrotetrabenazine or its derivatives. Despite the major limitation that beta-cells are low in abundance (1%-2%) and dispersed throughout the pancreas, VMAT2 PET is sensitive enough to detect VMAT2 signal and to allow kinetic model-based quantification of VMAT2 binding within the pancreas. However, these techniques are still in early stages, and careful further evaluations and technical developments are needed before they can be clinically used as a valid biomarker of BCM.
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Affiliation(s)
- Masanori Ichise
- Department of Radiology, Columbia University Medical College, New York, New York 11032, USA.
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Kotková Z, Kotek J, Jirák D, Jendelová P, Herynek V, Berková Z, Hermann P, Lukeš I. Cyclodextrin-Based Bimodal Fluorescence/MRI Contrast Agents: An Efficient Approach to Cellular Imaging. Chemistry 2010; 16:10094-102. [DOI: 10.1002/chem.200903519] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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