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- Cheung, Pierre, et al.
(author)
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Preclinical evaluation of Affibody molecule for PET imaging of human pancreatic islets derived from stem cells
- 2023
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In: EJNMMI Research. - : Springer Nature. - 2191-219X. ; 13:1
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Journal article (peer-reviewed)abstract
- Background: Beta-cell replacement methods such as transplantation of isolated donor islets have been proposed as a curative treatment of type 1 diabetes, but widespread application is challenging due to shortages of donor tissue and the need for continuous immunosuppressive treatments. Stem-cell-derived islets have been suggested as an alternative source of beta cells, but face transplantation protocols optimization difficulties, mainly due to a lack of available methods and markers to directly monitor grafts survival, as well as their localization and function. Molecular imaging techniques and particularly positron emission tomography has been suggested as a tool for monitoring the fate of islets after clinical transplantation. The integral membrane protein DGCR2 has been demonstrated to be a potential pancreatic islet biomarker, with specific expression on insulin-positive human embryonic stem-cell-derived pancreatic progenitor cells. The candidate Affibody molecule ZDGCR2:AM106 was radiolabeled with fluorine-18 using a novel click chemistry-based approach. The resulting positron emission tomography tracer [18F]ZDGCR2:AM106 was evaluated for binding to recombinant human DGCR2 and cryosections of stem-cell-derived islets, as well as in vivo using an immune-deficient mouse model transplanted with stem-cell-derived islets. Biodistribution of the [18F]ZDGCR2:AM106 was also assessed in healthy rats and pigs. Results: [18F]ZDGCR2:AM106 was successfully synthesized with high radiochemical purity and yield via a pretargeting approach. [18F]ZDGCR2:AM106 retained binding to recombinant human DCGR2 as well as to cryosectioned stem-cell-derived islets, but in vivo binding to native pancreatic tissue in both rat and pig was low. However, in vivo uptake of [18F]ZDGCR2:AM106 in stem-cell-derived islets transplanted in the immunodeficient mice was observed, albeit only within the early imaging frames after injection of the radiotracer. Conclusion: Targeting of DGCR2 is a promising approach for in vivo detection of stem-cell-derived islets grafts by molecular imaging. The synthesis of [18F]ZDGCR2:AM106 was successfully performed via a pretargeting method to label a site-specific covalently bonded fluorine-18 to the Affibody molecule. However, the rapid washout of [18F]ZDGCR2:AM106 from the stem-cell-derived islets graft indicates that dissociation kinetics can be improved. Further studies using alternative binders of similar classes with improved binding potential are warranted.
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- Eriksson, Carl, 1981-, et al.
(author)
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Ustekinumab Versus Anti-tumour Necrosis Factor Alpha Agents as Second-Line Biologics in Crohn's Disease
- 2023
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In: Digestive Diseases and Sciences. - : Springer-Verlag New York. - 0163-2116 .- 1573-2568. ; 68:7, s. 3119-3128
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Journal article (peer-reviewed)abstract
- BACKGROUND: There are little data on positioning biologics in Crohn's disease (CD). AIMS: We aimed to assess the comparative effectiveness and safety of ustekinumab vs tumour necrosis factor-alpha (anti-TNF) agents after first-line treatment with anti-TNF in CD.METHODS: We used Swedish nationwide registers to identify patients with CD, exposed to anti-TNF who initiated second-line biologic treatment with ustekinumab or second-line anti-TNF therapy. Nearest neighbour 1:1 propensity score matching (PSM) was used to balance the groups. The primary outcome was 3-year drug survival used as a proxy for effectiveness. Secondary outcomes included drug survival without hospital admission, CD-related surgery, antibiotics, hospitalization due to infection and exposure to corticosteroids.RESULTS: Some 312 patients remained after PSM. Drug survival at 3 years was 35% (95% CI 26-44%) in ustekinumab compared to 36% (95% CI 28-44%) in anti-TNF-treated patients (p = 0.72). No statistically significant differences were observed between the groups in 3-year survival without hospital admission (72% vs 70%, p = 0.99), surgery (87% vs 92%, p = 0.17), hospital admission due to infection (92% vs 92%, p = 0.31) or prescription of antibiotics (49% vs 50%, p = 0.56). The proportion of patients continuing second-line biologic therapy did not differ by reason for ending first-line anti-TNF (lack of response vs intolerance) or by type of first-line anti-TNF (adalimumab vs infliximab).CONCLUSION: Based on data from Swedish routine care, no clinically relevant differences in effectiveness or safety of second-line ustekinumab vs anti-TNF treatment were observed in patients with CD with prior exposure to anti-TNF.
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- Kehoe, Laura, et al.
(author)
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Make EU trade with Brazil sustainable
- 2019
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
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Journal article (other academic/artistic)
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| 5. |
- Wegrzyniak, Olivia, et al.
(author)
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Imaging of fibrogenesis in the liver by [18F]TZ-Z0959 : an Affibody molecule targeting platelet derived growth factor receptor β
- 2023
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In: EJNMMI Radiopharmacy and Chemistry. - : Springer Nature. - 2365-421X. ; 8:1
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Journal article (peer-reviewed)abstract
- Background: Platelet-derived growth factor receptor beta (PDGFRβ) is a receptor overexpressed on activated hepatic stellate cells (aHSCs). Positron emission tomography (PET) imaging of PDGFRβ could potentially allow the quantification of fibrogenesis in fibrotic livers. This study aims to evaluate a fluorine-18 radiolabeled Affibody molecule ([18F]TZ-Z09591) as a PET tracer for imaging liver fibrogenesis. Results: In vitro specificity studies demonstrated that the trans-Cyclooctenes (TCO) conjugated Z09591 Affibody molecule had a picomolar affinity for human PDGFRβ. Biodistribution performed on healthy rats showed rapid clearance of [18F]TZ-Z09591 through the kidneys and low liver background uptake. Autoradiography (ARG) studies on fibrotic livers from mice or humans correlated with histopathology results. Ex vivo biodistribution and ARG revealed that [18F]TZ-Z09591 binding in the liver was increased in fibrotic livers (p = 0.02) and corresponded to binding in fibrotic scars. Conclusions: Our study highlights [18F]TZ-Z09591 as a specific tracer for fibrogenic cells in the fibrotic liver, thus offering the potential to assess fibrogenesis clearly. Graphical abstract: [Figure not available: see fulltext.]
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