| 1. |
- Antoni, Gunnar, et al.
(författare)
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In Vivo Visualization and Quantification of Neutrophil Elastase in Lungs of COVID-19 Patients : A First-in-Humans PET Study with 11C-NES
- 2023
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 64:1, s. 145-148
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Tidskriftsartikel (refereegranskat)abstract
- COVID-19 can cause life-threatening lung-inflammation that is suggested to be mediated by neutrophils, whose effector mechanisms in COVID-19 is inexplicit. The aim of the present work is to evaluate a novel PET tracer for neutrophil elastase in COVID-19 patients and healthy controls.METHODS: In this open-label, First-In-Man study, four patients with hypoxia due to COVID-19 and two healthy controls were investigated with positron emission tomography (PET) using the new selective and specific neutrophil elastase PET-tracer [11C]GW457427 and [15O]water for the visualization and quantification of NE and perfusion in the lungs, respectively.RESULTS: [11C]GW457427 accumulated selectively in lung areas with ground-glass opacities on computed tomography characteristic of COVID-19 suggesting high levels on NE in these areas. In the same areas perfusion was severely reduced in comparison to healthy lung tissue as measured with [15O]water.CONCLUSION: The data suggests that NE may be responsible for the severe lung inflammation in COVID-19 patients and that inhibition of NE could potentially reduce the acute inflammatory process and improve the condition.
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| 2. |
- Eriksson, Olof, et al.
(författare)
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Glucagonlike Peptide-1 Receptor Imaging in Individuals with Type 2 Diabetes
- 2022
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 63:5, s. 794-800
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Tidskriftsartikel (refereegranskat)abstract
- The glucagonlike peptide-1 receptor (GLP1R) is a gut hormone receptor, intricately linked to regulation of blood glucose homeostasis via several mechanisms. It is an established and emergent drug target in metabolic disease. The PET radioligand 68Ga-DO3A-VS-exendin4 (68Ga-exendin4) has the potential to enable longitudinal studies of GLP1R in the human pancreas.Methods: 68Ga-exendin4 PET/CT examinations were performed on overweight-to-obese individuals with type 2 diabetes (n = 13) as part of a larger target engagement study (NCT03350191). A scanning protocol was developed to optimize reproducibility (target amount of 0.5 MBq/kg [corresponding to peptide amount of <0.2 µg/kg], blood sampling, and tracer stability assessment). The pancreas and abdominal organs were segmented, and binding was correlated with clinical parameters.Results: Uptake of 68Ga-exendin4 in the pancreas, but not in other abdominal tissues, was high but variable between individuals. There was no evidence of self-blocking of GLP1R by the tracer in this protocol, despite the high potency of exendin4. The results showed that a full dynamic scan can be simplified to a short static scan, potentially increasing throughput and reducing patient discomfort. The 68Ga-exendin4 concentration in the pancreas (i.e., GLP1R density) correlated inversely with the age of the individual and tended to correlate positively with body mass index. However, the total GLP1R content in the pancreas did not.Conclusion: In summary, we present an optimized and simplified 68Ga-exendin4 scanning protocol to enable reproducible imaging of GLP1R in the pancreas. 68Ga-exendin4 PET may enable quantification of longitudinal changes in pancreatic GLP1R during the development of type 2 diabetes, as well as target engagement studies of novel glucagonlike peptide-1 agonists.
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| 3. |
- Eriksson, Olof, et al.
(författare)
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Imaging of the Glucagon Receptor in Subjects with Type 2 Diabetes
- 2021
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Ingår i: Journal of Nuclear Medicine. - : SOC NUCLEAR MEDICINE INC. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 62:6, s. 833-838
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Tidskriftsartikel (refereegranskat)abstract
- Despite the importance of the glucagon receptor (GCGR) in disease and in pharmaceutical drug development, there is a lack of specific and sensitive biomarkers of its activation in humans. The PET radioligand Ga-68-DO3A-VS-Tuna-2 (Ga-68-Tuna-2) was developed to yield a noninvasive imaging marker for GCGR target distribution and drug target engagement in humans. Methods: The biodistribution and dosimetry of Ga-68-Tuna-2 was assessed by PET/CT in 13 individuals with type 2 diabetes as part of a clinical study assessing the occupancy of the dual GCGR/glucagon like peptide-1 receptor agonist SAR425899. Binding of Ga-68-Tuna-2 in liver and reference tissues was evaluated and correlated to biometrics (e.g., weight or body mass index) or other biomarkers (e.g., plasma glucagon levels). Results: Ga-68-Tuna-2 binding was seen primarily in the liver, which is in line with the strong expression of GCGR on hepatocytes. The kidneys demonstrated high excretion-related retention, whereas all other tissue demonstrated rapid washout. The SUV55 (min) (SUV during the last 10-min time frame, 50-60 min after administration) uptake endpoint was sensitive to endogenous levels of glucagon. Ga-68-Tuna-2 exhibited a safe dosimetry profile and no adverse events after intravenous administration. Conclusion: Ga-68-Tuna-2 can be used for safe and accurate assessment of the GCGR in human. It may serve as an important tool in understanding the in vivo pharmacology of novel drugs engaging the GCGR.
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| 4. |
- Eriksson, Olof, et al.
(författare)
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Quantitative Imaging of Serotonergic Biosynthesis and Degradation in the Endocrine Pancreas
- 2014
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 55:3, s. 460-465
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Tidskriftsartikel (refereegranskat)abstract
- Serotonergic biosynthesis in the endocrine pancreas, of which the islets of Langerhans is the major constituent, has been implicated in insulin release and β cell proliferation. In this study, we investigated the feasibility of quantitative noninvasive imaging of the serotonergic metabolism in the pancreas using the PET tracer (11)C-5-hydroxy-l-tryptophan ((11)C-5-HTP).METHODS: Uptake of (11)C-5-HTP, and its specificity for key enzymes in the serotonergic metabolic pathway, was assessed in vitro (INS-1 and PANC1 cells and human islet and exocrine preparations) and in vivo (nonhuman primates and healthy and diabetic rats).RESULTS: In vitro tracer uptake in endocrine cells (INS-1 and human islets), but not PANC1 and exocrine cells, was mediated specifically by intracellular conversion into serotonin. Pancreatic uptake of (11)C-5-HTP in nonhuman primates was markedly decreased by inhibition of the enzyme dopa decarboxylase, which converts (11)C-5-HTP to (11)C-serotonin and increased after inhibition of monoamine oxidase-A, the main enzyme responsible for serotonin degradation. Uptake in the rat pancreas was similarly modulated by inhibition of monoamine oxidase-A and was reduced in animals with induced diabetes.CONCLUSION: The PET tracer (11)C-5-HTP can be used for quantitative imaging of the serotonergic system in the endocrine pancreas.
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| 5. |
- Eriksson, Olof, et al.
(författare)
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The Cannabinoid Receptor-1 Is an Imaging Biomarker of Brown Adipose Tissue
- 2015
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 56:12, s. 1937-1941
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Tidskriftsartikel (refereegranskat)abstract
- Recently, the existence of significant deposits of brown adipose tissue (BAT) in human adults was confirmed. Its role in the human metabolism is unknown but could be substantial. Inhibition of the cannabinoid receptor-1 (CB1) by the antagonist rimonabant (SR141716) has been associated with activation of BAT thermogenesis and weight loss in mice and rats. The role of peripheral and central CB1 in the activation of BAT merits further investigation. Here we developed a technique for quantifying CB1 in BAT by PET. Methods: Sections of rat BAT and subcutaneous white adipose tissue (WAT) were stained for CB1 and uncoupling protein-1 by immunofluorescent staining. Binding of the radiolabeled CB1 antagonist (3R,5R)-5-(3-(18F-fluoromethoxy)phenyl)-3-(((R)-1-phenylethyl)amino)-1-(4-(trifluoromethyl)-phenyl)pyrrolidin-2-one (F-18-FMPEP-d(2)) to BAT in vivo and in vitro was assessed in rats by PET. Results: We found that CB1 was colocalized with uncoupling protein-1 in BAT, but neither protein was found in WAT. Binding of the radiotracer to BAT sections (but not WAT) in vitro was high and displaceable by pretreatment with rimonabant. Deposits of BAT in rats had significant binding of F-18-FMPEP-d(2) in vivo, indicating high CB1 density. WAT deposits were negative for F-18-FMPEP-d(2), consistent with the immunofluorescent staining and in vitro results. Conclusion: F-18-FMPEP-d(2) PET can quantify CB1 density noninvasively in vivo in rats. CB1 is therefore a promising surrogate imaging biomarker for assessing the presence of BAT deposits as well as for elucidating the mechanism of CB1 antagonist-mediated weight loss.
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| 6. |
- Puuvuori, Emmi, et al.
(författare)
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PET imaging of neutrophil elastase with 11C-GW457427 in Acute Respiratory Distress Syndrome in pigs
- 2023
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine and Molecular Imaging. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 64:3, s. 423-429
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Tidskriftsartikel (refereegranskat)abstract
- Today, there is a lack of clinically available imaging techniques to detect and quantify specific immune cell populations. Neutrophils are one of the first immune cells at the site of inflammation, and they secrete the serine protease neutrophil elastase (NE), which is crucial in the fight against pathogens. However, the prolonged lifespan of neutrophils increases the risk that patients will develop severe complications, such as acute respiratory distress syndrome (ARDS). Here, we evaluated the novel radiolabeled NE inhibitor 11C-GW457427 in a pig model of ARDS, for detection and quantification of neutrophil activity in the lungs. Methods: ARDS was induced by intravenous administration of oleic acid to 5 farm pigs, and 4 were considered healthy controls. The severity of ARDS was monitored by clinical parameters of lung function and plasma biomarkers. Each pig was studied with 11C-GW457427 and PET/CT, before and after pretreatment with the NE inhibitor GW311616 to determine in vivo binding specificity. PET image data were analyzed as SUVs and correlated with immunohistochemical staining for NE in biopsies. Results: The binding of 11C-GW457427 was increased in pig lungs with induced ARDS (median SUVmean, 1.91; interquartile range [IQR], 1.67-2.55) compared with healthy control pigs (P < 0.05 and P = 0.03, respectively; median SUVmean, 1.04; IQR, 0.66-1.47). The binding was especially strong in lung regions with high levels of NE and ongoing inflammation, as verified by immunohisto-chemistry. The binding was successfully blocked by pretreatment of an NE inhibitor drug, which demonstrated the in vivo specificity of 11C-GW457427 (P < 0.05 and P = 0.04, respectively; median SUVmean, 0.60; IQR, 0.58-0.77). The binding in neutrophil-rich tissues such as bone marrow (P < 0.05 and P = 0.04, respectively; baseline median SUVmean, 5.01; IQR, 4.48-5.49; block median SUVmean, 1.57; IQR, 0.95-1.85) and spleen (median SUVmean, 2.14; IQR, 1.19-2.36) was also high in all pigs. Conclusion: 11C-GW457427 binds to NE in a porcine model of oleic acid-induced lung inflammation in vivo, with a specific increase in regional lung, bone marrow, and spleen SUV. 11C-GW457427 is a promising tool for localizing, tracking, and quantifying neutrophil-facilitated inflammation in clinical diagnostics and drug development.
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| 7. |
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| 8. |
- Selvaraju, Ram K., et al.
(författare)
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In Vivo Imaging of the Glucagonlike Peptide 1 Receptor in the Pancreas with Ga-68-Labeled DO3A-Exendin-4
- 2013
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 54:8, s. 1458-1463
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Tidskriftsartikel (refereegranskat)abstract
- The glucagonlike peptide 1 receptor (GLP-1R) is mainly expressed on beta-cells in the Wets of Langerhans and is therefore an attractive target for imaging of the beta-cell mass. In the present study, Ga-68-labeled exendin-4 was evaluated for PET imaging and quantification of GLP-1R in the pancreas. Methods: Dose escalation studies of Ga-68-labeled 1,4,7-tris(carboxymethylaza)cyclododecane-10-azaacetyl (DO3A)-exendin-4 were performed in rats (organ distribution) and cynomolgus monkeys (PET/CT imaging) to determine the GLP-1R-specific tissue uptake in vivo. Pancreatic uptake (as determined by organ distribution) in healthy rats was compared with that in diabetic rats. GLP-1R occupancy in the cynomolgus pancreas was quantified with a 1-tissue-compartment model. Results: In rodents, uptake in the pancreas was decreased from the baseline by up to 90% (P < 0.0001) by coadministration of DO3A-exendin-4 at 100 mu g/kg. Pancreatic uptake in diabetic animals was decreased by more than 80% (P < 0.001) compared with that in healthy controls, as measured by organ distribution. GLP-1R occupancy in the cynomolgus pancreas after coinjection of DO3A-exendin-4 at 0.15-20 mu g/kg ranged from 49% to 97%, as estimated by compartment modeling. Conclusion: These results strongly support the notion that Ga-68-DO3A-exendin-4 uptake in the pancreas is mediated by specific receptor binding. In addition, pancreatic uptake was decreased by selective destruction of beta-cells. This result suggests that GLP-1R can be quantified in vivo, which has major implications for the prospect of imaging of native beta-cells.
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| 9. |
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| 10. |
- Tolmachev, Vladimir, et al.
(författare)
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Imaging of platelet-derived growth factor receptor β expression in glioblastoma xenografts using affibody molecule 111In-DOTA-Z09591
- 2014
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 55:2, s. 294-300
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Tidskriftsartikel (refereegranskat)abstract
- The overexpression and excessive signaling of platelet-derived growth factor receptor β (PDGFRβ) has been detected in cancers, atherosclerosis, and a variety of fibrotic diseases. Radionuclide in vivo visualization of PDGFRβ expression might help to select PDGFRβ targeting treatment for these diseases. The goal of this study was to evaluate the feasibility of in vivo radionuclide imaging of PDGFRβ expression using an Affibody molecule, a small nonimmunoglobulin affinity protein.MethodsThe PDGFRβ-binding Z09591 Affibody molecule was site-specifically conjugated with a maleimido derivative of DOTA and labeled with 111In. Targeting of the PDGFRβ-expressing U-87 MG glioblastoma cell line using 111In-DOTA-Z09591 was evaluated in vitro and in vivo.ResultsDOTA-Z09591 was stably labeled with 111In with preserved specific binding to PDGFRβ-expressing cells in vitro. The dissociation constant for 111In-DOTA-Z09591 binding to U-87 MG cells was determined to be 92 ± 10 pM. In mice bearing U-87 MG xenografts, the tumor uptake of 111In-DOTA-Z09591 was 7.2 ± 2.4 percentage injected dose per gram and the tumor-to-blood ratio was 28 ± 14 at 2 h after injection. In vivo receptor saturation experiments demonstrated that targeting of U-87 MG xenografts in mice was PDGFRβ-specific. U-87 MG xenografts were clearly visualized using small-animal SPECT/CT at 3 h after injection.ConclusionThis study demonstrates the feasibility of in vivo visualization of PDGFRβ-expressing xenografts using an Affibody molecule. Further development of radiolabeled Affibody molecules might provide a useful clinical imaging tool for PDGFRβ expression during various pathologic conditions.
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