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[ 18F]MK-7246 for Positron Emission Tomography Imaging of the Beta-Cell Surface Marker GPR44. Pharmaceutics 2023; 15:pharmaceutics15020499. [PMID: 36839820 PMCID: PMC9962486 DOI: 10.3390/pharmaceutics15020499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/27/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
The progressive loss of beta-cell mass is a hallmark of diabetes and has been suggested as a complementary approach to studying the progression of diabetes in contrast to the beta-cell function. Non-invasive nuclear medicinal imaging techniques such as Positron Emission Tomography using radiation emitting tracers have thus been suggested as more viable methodologies to visualize and quantify the beta-cell mass with sufficient sensitivity. The transmembrane G protein-coupled receptor GPR44 has been identified as a biomarker for monitoring beta-cell mass. MK-7246 is a GPR44 antagonist that selectively binds to GPR44 with high affinity and good pharmacokinetic properties. Here, we present the synthesis of MK-7246, radiolabeled with the positron emitter fluorine-18 for preclinical evaluation using cell lines, mice, rats and human pancreatic cells. Here, we have described a synthesis and radiolabeling method for producing [18F]MK-7246 and its precursor compound. Preclinical assessments demonstrated the strong affinity and selectivity of [18F]MK-7246 towards GPR44. Additionally, [18F]MK-7246 exhibited excellent metabolic stability, a fast clearance profile from blood and tissues, qualifying it as a promising radioactive probe for GPR44-directed PET imaging.
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Jansen TJP, Brom M, Boss M, Buitinga M, Tack CJ, van Meijel LA, de Galan BE, Gotthardt M. Importance of beta cell mass for glycaemic control in people with type 1 diabetes. Diabetologia 2023; 66:367-375. [PMID: 36394644 PMCID: PMC9669532 DOI: 10.1007/s00125-022-05830-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 10/10/2022] [Indexed: 11/18/2022]
Abstract
AIMS/HYPOTHESIS The role of beta cell mass in the balance of glucose control and hypoglycaemic burden in people with type 1 diabetes is unclear. We applied positron emission tomography (PET) imaging with radiolabelled exendin to compare beta cell mass among people with type 1 diabetes and either low glucose variability (LGV) or high glucose variability (HGV). METHODS All participants with either LGV (n=9) or HGV (n=7) underwent a mixed-meal tolerance test to determine beta cell function and wore a blinded continuous glucose monitor for a week. After an i.v. injection with [68Ga]Ga-NODAGA-exendin-4, PET images were acquired for the quantification of pancreatic uptake of radiolabelled exendin. The mean standardised uptake value (SUVmean) of the pancreas was used to determine the amount of beta cell mass. RESULTS Participants with LGV had lower HbA1c (46.0 mmol/mol [44.5-52.5] [6.4% (6.3-7)] vs 80 mmol/mol [69.0-110] [9.5% (8.5-12.2)], p=0.001) and higher time in range (TIR) (75.6% [73.5-90.3] vs 38.7% [25.1-48.5], p=0.002) than those with HGV. The SUVmean of the pancreas was higher for the LGV than for the HGV group (5.1 [3.6-5.6] vs 2.9 [2.1-3.4], p=0.008). The AUCC-peptide:AUCglucose ratio was numerically, but not statistically, higher in the LGV compared with the HGV group (2.7×10-2 [6.2×10-4-5.3×10-2] vs 9.3×10-4 [4.7×10-4-5.2×10-3], p=0.21). SUVmean correlated with the AUCC-peptide:AUCglucose ratio (Pearson r=0.64, p=0.01), as well as with the TIR (r=0.64, p=0.01) and the SD of interstitial glucose levels (r=-0.66, p=0.007). CONCLUSION/INTERPRETATION Our data show higher beta cell mass in people with type 1 diabetes and LGV than in those with HGV, independent of beta cell function.
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Affiliation(s)
- Theodorus J P Jansen
- Department of Medical Imaging, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Maarten Brom
- Department of Medical Imaging, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Marti Boss
- Department of Medical Imaging, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Mijke Buitinga
- Nutrition and Movement Sciences, Maastricht University, Maastricht, the Netherlands
- Radiology and Nuclear Medicine, Maastricht UMC+, Maastricht, the Netherlands
| | - Cees J Tack
- Internal Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Lian A van Meijel
- Internal Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
- Internal Medicine, Maxima Medical Center, Veldhoven, the Netherlands
| | - Bastiaan E de Galan
- Internal Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
- Internal Medicine, Maastricht UMC+, Maastricht, the Netherlands
- CARIM School for Cardiovascular Disease, Maastricht University, Maastricht, the Netherlands
| | - Martin Gotthardt
- Department of Medical Imaging, Radboud University Medical Center, Nijmegen, the Netherlands
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Cheung P, Eriksson O. The Current State of Beta-Cell-Mass PET Imaging for Diabetes Research and Therapies. Biomedicines 2021; 9:1824. [PMID: 34944640 PMCID: PMC8698817 DOI: 10.3390/biomedicines9121824] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 11/28/2021] [Accepted: 11/30/2021] [Indexed: 12/03/2022] Open
Abstract
Diabetes is a chronic metabolic disease affecting over 400 million people worldwide and one of the leading causes of death, especially in developing nations. The disease is characterized by chronic hyperglycemia, caused by defects in the insulin secretion or action pathway. Current diagnostic methods measure metabolic byproducts of the disease such as glucose level, glycated hemoglobin (HbA1c), insulin or C-peptide levels, which are indicators of the beta-cell function. However, they inaccurately reflect the disease progression and provide poor longitudinal information. Beta-cell mass has been suggested as an alternative approach to study disease progression in correlation to beta-cell function, as it behaves differently in the diabetes physiopathology. Study of the beta-cell mass, however, requires highly invasive and potentially harmful procedures such as pancreatic biopsies, making diagnosis and monitoring of the disease tedious. Nuclear medical imaging techniques using radiation emitting tracers have been suggested as strong non-invasive tools for beta-cell mass. A highly sensitive and high-resolution technique, such as positron emission tomography, provides an ideal solution for the visualization of beta-cell mass, which is particularly essential for better characterization of a disease such as diabetes, and for estimating treatment effects towards regeneration of the beta-cell mass. Development of novel, validated biomarkers that are aimed at beta-cell mass imaging are thus highly necessary and would contribute to invaluable breakthroughs in the field of diabetes research and therapies. This review aims to describe the various biomarkers and radioactive probes currently available for positron emission tomography imaging of beta-cell mass, as well as highlight the need for precise quantification and visualization of the beta-cell mass for designing new therapy strategies and monitoring changes in the beta-cell mass during the progression of diabetes.
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Affiliation(s)
- Pierre Cheung
- Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, SE-75183 Uppsala, Sweden;
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4
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Espes D, Carlsson PO, Selvaraju RK, Rosestedt M, Cheung P, Ahlström H, Korsgren O, Eriksson O. Longitudinal Assessment of 11C-5-Hydroxytryptophan Uptake in Pancreas After Debut of Type 1 Diabetes. Diabetes 2021; 70:966-975. [PMID: 33479059 DOI: 10.2337/db20-0776] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 01/18/2021] [Indexed: 11/13/2022]
Abstract
The longitudinal alterations of the pancreatic β-cell and islet mass in the progression of type 1 diabetes (T1D) are still poorly understood. The objective of this study was to repeatedly assess the endocrine volume and the morphology of the pancreas for up to 24 months after T1D diagnosis (n = 16), by 11C-5-hydroxytryptophan (11C-5-HTP) positron emission tomography (PET) and MRI. Study participants were examined four times by PET/MRI: at recruitment and then after 6, 12, and 24 months. Clinical examinations and assessment of β-cell function by a mixed-meal tolerance test and fasting blood samples were performed in connection with the imaging examination. Pancreas volume has a tendency to decrease from 50.2 ± 10.3 mL at T1D debut to 42.2 ± 14.6 mL after 24 months (P < 0.098). Pancreas uptake of 11C-5-HTP (e.g., the volume of the endocrine pancreas) did not decrease from T1D diagnosis (0.23 ± 0.10 % of injected dose) to 24-month follow-up, 0.21 ± 0.14% of injected dose, and exhibited low interindividual changes. Pancreas perfusion was unchanged from diagnosis to 24-month follow-up. The pancreas uptake of 11C-5-HTP correlated with the long-term metabolic control as estimated by HbA1c (P < 0.05). Our findings argue against a major destruction of β-cell or islet mass in the 2-year period after diagnosis of T1D.
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Affiliation(s)
- Daniel Espes
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Per-Ola Carlsson
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Ram Kumar Selvaraju
- Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Maria Rosestedt
- Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Pierre Cheung
- Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Håkan Ahlström
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
- Antaros Medical AB, Mölndal, Sweden
| | - Olle Korsgren
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Olof Eriksson
- Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
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Thapa B, Suh EH, Parrott D, Khalighinejad P, Sharma G, Chirayil S, Sherry AD. Imaging β-Cell Function Using a Zinc-Responsive MRI Contrast Agent May Identify First Responder Islets. Front Endocrinol (Lausanne) 2021; 12:809867. [PMID: 35173681 PMCID: PMC8842654 DOI: 10.3389/fendo.2021.809867] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 12/16/2021] [Indexed: 01/05/2023] Open
Abstract
An imaging method for detecting β-cell function in real-time in the rodent pancreas could provide new insights into the biological mechanisms involving loss of β-cell function during development of type 2 diabetes and for testing of new drugs designed to modulate insulin secretion. In this study, we used a zinc-responsive MRI contrast agent and an optimized 2D MRI method to show that glucose stimulated insulin and zinc secretion can be detected as functionally active "hot spots" in the tail of the rat pancreas. A comparison of functional images with histological markers show that insulin and zinc secretion does not occur uniformly among all pancreatic islets but rather that some islets respond rapidly to an increase in glucose while others remain silent. Zinc and insulin secretion was shown to be altered in streptozotocin and exenatide treated rats thereby verifying that this simple MRI technique is responsive to changes in β-cell function.
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Affiliation(s)
- Bibek Thapa
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Eul Hyun Suh
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Daniel Parrott
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
- Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Pooyan Khalighinejad
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Gaurav Sharma
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Sara Chirayil
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - A. Dean Sherry
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, United States
- Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, TX, United States
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, United States
- *Correspondence: A. Dean Sherry, ;
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6
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Demine S, Schulte ML, Territo PR, Eizirik DL. Beta Cell Imaging-From Pre-Clinical Validation to First in Man Testing. Int J Mol Sci 2020; 21:E7274. [PMID: 33019671 PMCID: PMC7582644 DOI: 10.3390/ijms21197274] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/21/2020] [Accepted: 09/28/2020] [Indexed: 12/14/2022] Open
Abstract
There are presently no reliable ways to quantify human pancreatic beta cell mass (BCM) in vivo, which prevents an accurate understanding of the progressive beta cell loss in diabetes or following islet transplantation. Furthermore, the lack of beta cell imaging hampers the evaluation of the impact of new drugs aiming to prevent beta cell loss or to restore BCM in diabetes. We presently discuss the potential value of BCM determination as a cornerstone for individualized therapies in diabetes, describe the presently available probes for human BCM evaluation, and discuss our approach for the discovery of novel beta cell biomarkers, based on the determination of specific splice variants present in human beta cells. This has already led to the identification of DPP6 and FXYD2ga as two promising targets for human BCM imaging, and is followed by a discussion of potential safety issues, the role for radiochemistry in the improvement of BCM imaging, and concludes with an overview of the different steps from pre-clinical validation to a first-in-man trial for novel tracers.
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Affiliation(s)
- Stephane Demine
- Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA;
| | - Michael L. Schulte
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (M.L.S.); (P.R.T.)
| | - Paul R. Territo
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (M.L.S.); (P.R.T.)
- Division of Clinical Pharmacology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Decio L. Eizirik
- Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA;
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
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7
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News ways of understanding the complex biology of diabetes using PET. Nucl Med Biol 2020; 92:65-71. [PMID: 32387114 DOI: 10.1016/j.nucmedbio.2020.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/27/2020] [Accepted: 04/15/2020] [Indexed: 11/22/2022]
Abstract
The understanding of metabolic disease and diabetes on a molecular level has increased significantly due to the recent advances in molecular biology and biotechnology. However, in vitro studies and animal models do not always translate to the human disease, perhaps illustrated by the failure of many drug candidates in the clinical phase. Non-invasive biomedical imaging techniques such as Positron Emission Tomography (PET) offer tools for direct visualization and quantification of molecular processes in humans. Developments in this area potentially enable longitudinal in vivo studies of receptors and processes involved in diabetes guiding drug development and diagnosis in the near future. This mini-review focuses on describing the overall perspective of how PET can be used to increase our understanding and improve treatment of diabetes. The methodological aspects and future developments and challenges are highlighted.
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8
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Demine S, Garcia Ribeiro R, Thevenet J, Marselli L, Marchetti P, Pattou F, Kerr-Conte J, Devoogdt N, Eizirik DL. A nanobody-based nuclear imaging tracer targeting dipeptidyl peptidase 6 to determine the mass of human beta cell grafts in mice. Diabetologia 2020; 63:825-836. [PMID: 31873789 DOI: 10.1007/s00125-019-05068-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 10/30/2019] [Indexed: 11/24/2022]
Abstract
AIMS/HYPOTHESIS Type 1 diabetes is characterised by a progressive decline in beta cell mass. This is also observed following implantation of pancreatic islet allografts, but there is no reliable information regarding the time course of beta cell loss. This is due to the limited availability of non-invasive pancreatic islet imaging techniques. We have previously described that dipeptidyl peptidase 6 (DPP6) is an alpha and beta cell-specific biomarker, and developed a camelid antibody (nanobody '4hD29') against it. We demonstrated the possibility to detect DPP6-expressing cells by single-photon emission computed tomography (SPECT)/ computed tomography (CT), but the correlation between the number of cells grafted and the SPECT signal was not assessed. Here, we investigate whether the 4hD29 nanobody allows us to detect different amounts of human pancreatic islets implanted into immune-deficient mice. In addition, we also describe the adaptation of the probe for use with positron emission tomography (PET). METHODS DPP6 expression was assessed in human samples using tissue arrays and immunohistochemistry. The effect of the 4hD29 nanobody on cell death and glucose-stimulated insulin secretion was measured in EndoC-βH1 cells and in human islets using Hoechst/propidium iodide staining and an anti-insulin ELISA, respectively. We performed in vivo SPECT imaging on severe combined immunodeficient (SCID) mice transplanted with different amounts of EndoC-βH1 cells (2 × 106, 5 × 106 and 10 × 106 cells), human islets (1000 and 3000) or pancreatic exocrine tissue using 99mTc-labelled 4hD29 nanobody. This DPP6 nanobody was also conjugated to N-chlorosuccinimide (NCS)-1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA), radiolabelled with either 67Ga (SPECT) or 68Ga (PET) and used in a proof-of-principle experiment to detect DPP6-expressing cells (Kelly neuroblastoma) grafted in SCID mice. RESULTS The DPP6 protein is mainly expressed in pancreatic islets. Importantly, the anti-DPP6 nanobody 4hD29 allows non-invasive detection of high amounts of EndoC-βH1 cells or human islets grafted in immunodeficient mice. This suggests that the probe must be further improved to detect lower numbers of islet cells. The 4hD29 nanobody neither affected beta cell viability nor altered insulin secretion in EndoC-βH1 cells and human islets. The conversion of 4hD29 nanobody into a PET probe was successful and did not alter its specificity. CONCLUSIONS/INTERPRETATION These findings suggest that the anti-DPP6 4hD29 nanobody may become a useful tool for the quantification of human islet grafts in mice and, pending future development, islet mass in individuals with diabetes.
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Affiliation(s)
- Stéphane Demine
- ULB Center for Diabetes Research and Welbio, Medical Faculty, Université Libre de Bruxelles (ULB), Route de Lennik 808-CP618, 1070, Brussels, Belgium.
| | - Rita Garcia Ribeiro
- In Vivo Cellular and Molecular Imaging Laboratory (ICMI), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Julien Thevenet
- European Genomic Institute for Diabetes, UMR 1190 Translational Research for Diabetes, Inserm, CHU Lille, University of Lille, Lille, France
| | - Lorella Marselli
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Piero Marchetti
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - François Pattou
- European Genomic Institute for Diabetes, UMR 1190 Translational Research for Diabetes, Inserm, CHU Lille, University of Lille, Lille, France
| | - Julie Kerr-Conte
- European Genomic Institute for Diabetes, UMR 1190 Translational Research for Diabetes, Inserm, CHU Lille, University of Lille, Lille, France
| | - Nick Devoogdt
- In Vivo Cellular and Molecular Imaging Laboratory (ICMI), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Decio L Eizirik
- ULB Center for Diabetes Research and Welbio, Medical Faculty, Université Libre de Bruxelles (ULB), Route de Lennik 808-CP618, 1070, Brussels, Belgium
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9
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Nucleic acid-based theranostics in type 1 diabetes. Transl Res 2019; 214:50-61. [PMID: 31491371 DOI: 10.1016/j.trsl.2019.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 08/01/2019] [Accepted: 08/17/2019] [Indexed: 12/12/2022]
Abstract
Application of RNAi interference for type 1 diabetes (T1D) therapy bears tremendous potential. This review will discuss vehicles for oligonucleotide delivery, imaging modalities used for delivery monitoring, therapeutic targets, and different theranostic strategies that can be applied for T1D treatment.
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10
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Fujita N, Fujimoto H, Hamamatsu K, Murakami T, Kimura H, Toyoda K, Saji H, Inagaki N. Noninvasive longitudinal quantification of β-cell mass with [ 111In]-labeled exendin-4. FASEB J 2019; 33:11836-11844. [PMID: 31370679 PMCID: PMC6902711 DOI: 10.1096/fj.201900555rr] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 07/09/2019] [Indexed: 01/09/2023]
Abstract
Currently, quantifying β-cell mass (BCM) requires harvesting the pancreas. In this study, we investigated a potential noninvasive method to quantify BCM changes longitudinally using [Lys12(111In-BnDTPA-Ahx)]exendin-4 ([111In]-Ex4) and single-photon emission computed tomography (SPECT). We used autoradiography and transgenic mice expressing green fluorescent protein under the control of mouse insulin 1 gene promotor to evaluate the specificity of [111In]-Ex4 toward β cells. Using nonobese diabetic (NOD) mice, we injected [111In]-Ex4 (3.0 MBq) intravenously and performed SPECT 30 min later, repeating this at a 2-wk interval. After the second scan, we harvested the pancreas and calculated BCM from immunohistochemically stained pancreatic sections. Specific accumulation of [111In]-Ex4 in β cells was confirmed by autoradiography, with a significant correlation (r = 0.94) between the fluorescent and radioactive signal intensities. The radioactive signal from the pancreas in the second SPECT scan significantly correlated (r = 0.89) with BCM calculated from the immunostained pancreatic sections. We developed a regression formula to estimate BCM from the radioactive signals from the pancreas in SPECT scans. BCM can be quantified longitudinally and noninvasively by SPECT imaging with [111In]-Ex4. This technique successfully demonstrated longitudinal changes in BCM in NOD mice before and after onset of hyperglycemia.-Fujita, N., Fujimoto, H., Hamamatsu, K., Murakami, T., Kimura, H., Toyoda, K., Saji, H., Inagaki, N. Noninvasive longitudinal quantification of β-cell mass with [111In]-labeled exendin-4.
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Affiliation(s)
- Naotaka Fujita
- Department of Diabetes, Endocrinology, and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hiroyuki Fujimoto
- Department of Diabetes, Endocrinology, and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- Radioisotope Research Center, Agency for Health, Safety, and Environment, Kyoto University, Kyoto, Japan
| | - Keita Hamamatsu
- Department of Diabetes, Endocrinology, and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takaaki Murakami
- Department of Diabetes, Endocrinology, and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hiroyuki Kimura
- Department of Analytical and Bioinorganic Chemistry, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Kentaro Toyoda
- Department of Diabetes, Endocrinology, and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hideo Saji
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Nobuya Inagaki
- Department of Diabetes, Endocrinology, and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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11
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Khera E, Zhang L, Roberts S, Nessler I, Sandoval D, Reiner T, Thurber GM. Blocking of Glucagonlike Peptide-1 Receptors in the Exocrine Pancreas Improves Specificity for β-Cells in a Mouse Model of Type 1 Diabetes. J Nucl Med 2019; 60:1635-1641. [PMID: 31076502 DOI: 10.2967/jnumed.118.224881] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 05/03/2019] [Indexed: 01/18/2023] Open
Abstract
The diabetes community has long desired an imaging agent to quantify the number of insulin-secreting β-cells, beyond just functional equivalents (insulin secretion), to help diagnose and monitor early stages of both type 1 and type 2 diabetes mellitus. Loss in the number of β-cells can be masked by a compensatory increase in function of the remaining cells. Since β-cells form only about 1% of the pancreas and decrease as the disease progresses, only a few imaging agents, such as exendin, have demonstrated clinical potential to detect a drop in the already scarce signal. However, clinical translation of imaging with exendin has been hampered by pancreatic uptake that is higher than expected in subjects with long-term diabetes who lack β-cells. Exendin binds glucagonlike peptide-1 receptor (GLP-1R), previously thought to be expressed only on β-cells, but recent studies report low levels of GLP-1R on exocrine cells, complicating β-cell mass quantification. Methods: Here, we used a GLP-1R knockout mouse model to demonstrate that exocrine binding of exendin is exclusively via GLP-1R (∼1,000/cell) and not any other receptor. We then used lipophilic Cy-7 exendin to selectively preblock exocrine GLP-1R in healthy and streptozotocin-induced diabetic mice. Results: Sufficient receptors remain on β-cells for subsequent labeling with a fluorescent- or 111In-exendin. Conclusion: Selective GLP-1R blocking, which improves contrast between healthy and diabetic pancreata and provides a potential avenue for achieving the long-standing goal of imaging β-cell mass in the clinic.
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Affiliation(s)
- Eshita Khera
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan
| | - Liang Zhang
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan
| | - Sheryl Roberts
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Ian Nessler
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan
| | - Darleen Sandoval
- Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan
| | - Thomas Reiner
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York.,Department of Radiology, Weill Cornell Medical College, New York, New York.,Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York; and
| | - Greg M Thurber
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan .,Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan
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