| 1. |
- Ahmed, M., et al.
(författare)
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Human serum albumin-based probes for molecular targeting of macrophage scavenger receptors
- 2019
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Ingår i: International Journal of Nanomedicine. - 1176-9114 .- 1178-2013. ; 14, s. 3723-3741
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Tidskriftsartikel (refereegranskat)abstract
- Background: Inflammation and accumulation of macrophages are key features of unstable atherosclerotic plaques. The ability of macrophages to take up molecular probes can be exploited in new clinical imaging methods for the detection of unstable atherosclerotic lesions. We investigated whether modifications of human serum albumin (HSA) could be used to target macrophages efficiently in vitro. Materials and methods: Maleylated and aconitylated HSA were compared with unmodified HSA. Fluorescent or radiolabeled (89 Zr) modified HSA was used in in vitro experiments to study cellular uptake by differentiated THP-1 cells and primary human macrophages. The time course of uptake was evaluated by flow cytometry, confocal microscopy, real-time microscopy and radioactivity measurements. The involvement of scavenger receptors (SR-A1, SR-B2, LOX-1) was assessed by knockdown experiments using RNA interference, by blocking experiments and by assays of competition by modified low-density lipoprotein. Results: Modified HSA was readily taken up by different macrophages. Uptake was mediated nonexclusively via the scavenger receptor SR-A1 (encoded by the MSR1 gene). Knockdown of CD36 and ORL1 had no influence on the uptake. Modified HSA was preferentially taken up by human macrophages compared with other vascular cell types such as endothelial cells and smooth muscle cells. Conclusions: Modified89Zr-labeled HSA probes were recognized by different subsets of polarized macrophages, and maleylated HSA may be a promising radiotracer for radio-nuclide imaging of macrophage-rich inflammatory vascular diseases. © 2019 Ahmed et al.
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| 2. |
- Ahmed, M., et al.
(författare)
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Molecular Imaging of a New Multimodal Microbubble for Adhesion Molecule Targeting
- 2019
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Ingår i: Cellular and Molecular Bioengineering. - : Springer Science and Business Media LLC. - 1865-5025 .- 1865-5033. ; 12:1, s. 15-32
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionInflammation is an important risk-associated component of many diseases and can be diagnosed by molecular imaging of specific molecules. The aim of this study was to evaluate the possibility of targeting adhesion molecules on inflammation-activated endothelial cells and macrophages using an innovative multimodal polyvinyl alcohol-based microbubble (MB) contrast agent developed for diagnostic use in ultrasound, magnetic resonance, and nuclear imaging.MethodsWe assessed the binding efficiency of antibody-conjugated multimodal contrast to inflamed murine or human endothelial cells (ECs), and to peritoneal macrophages isolated from rats with peritonitis, utilizing the fluorescence characteristics of the MBs. Single-photon emission tomography (SPECT) was used to illustrate Tc-99m-labeled MB targeting and distribution in an experimental in vivo model of inflammation.ResultsFlow cytometry and confocal microscopy showed that binding of antibody-targeted MBs to the adhesion molecules ICAM-1, VCAM-1, or E-selectin, expressed on cytokine-stimulated ECs, was up to sixfold higher for human and 12-fold higher for mouse ECs, compared with that of non-targeted MBs. Under flow conditions, both VCAM-1- and E-selectin-targeted MBs adhered more firmly to stimulated human ECs than to untreated cells, while VCAM-1-targeted MBs adhered best to stimulated murine ECs. SPECT imaging showed an approximate doubling of signal intensity from the abdomen of rats with peritonitis, compared with healthy controls, after injection of anti-ICAM-1-MBs.ConclusionsThis novel multilayer contrast agent can specifically target adhesion molecules expressed as a result of inflammatory stimuli in vitro, and has potential for use in disease-specific multimodal diagnostics in vivo using antibodies against targets of interest.
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| 3. |
- Ahmed, M., et al.
(författare)
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Molecular Imaging of Inflammation in a Mouse Model of Atherosclerosis Using a Zirconium-89-Labeled Probe
- 2020
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Ingår i: International Journal of Nanomedicine. - 1178-2013. ; 15, s. 6137-6152
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Tidskriftsartikel (refereegranskat)abstract
- Background: Beyond clinical atherosclerosis imaging of vessel stenosis and plaque morphology, early detection of inflamed atherosclerotic lesions by molecular imaging could improve risk assessment and clinical management in high-risk patients. To identify inflamed atherosclerotic lesions by molecular imaging in vivo, we studied the specificity of our radiotracer based on maleylated (Mal) human serum albumin (HSA), which targets key features of unstable atherosclerotic lesions. Materials and Methods: Mal-HSA was radiolabeled with a positron-emitting metal ion, zirconium-89 (Zr-89(4+)). The targeting potential of this probe was compared with unspecific Zr-89-HSA and F-18-FDG in an experimental model of atherosclerosis (Apoe(-/-) mice, n=22), and compared with wild-type (WT) mice (C57BL/6J, n=21) as controls. Results: PET/MRI, gamma counter measurements, and autoradiography showed the accumulation of Zr-89-Mal-HSA in the atherosclerotic lesions of Apoe(-/-) mice. The maximum standardized uptake values (SUVmax) for Zr-89-Mal-HSA at 16 and 20 weeks were 26% and 20% higher (P<0.05) in Apoe(-/-) mice than in control WT mice, whereas no difference in SUVmax was observed for F-18-FDG in the same animals. Zr-89-Mal-HSA uptake in the aorta, as evaluated by a gamma counter 48 h postinjection, was 32% higher (P<0.01) for Apoe(-/-) mice than in WT mice, and the aorta-to-blood ratio was 8-fold higher (P<0.001) for Zr-89-Mal-HSA compared with unspecific Zr-89-HSA. HSA-based probes were mainly distributed to the liver, spleen, kidneys, bone, and lymph nodes. The phosphor imaging autoradiography (PI-ARG) results corroborated the PET and gamma counter measurements, showing higher accumulation of Zr-89-Mal-HSA in the aortas of Apoe(-/-) mice than in WT mice (9.4 +/- 1.4 vs 0.8 +/- 0.3%; P<0.001). Conclusion: Zr-89 radiolabeling of Mal-HSA probes resulted in detectable activity in atherosclerotic lesions in aortas of Apoe(-/-) mice, as demonstrated by quantitative in vivo PET/MRI. Zr-89-Mal-HSA appears to be a promising diagnostic tool for the early identification of macrophage-rich areas of inflammation in atherosclerosis.
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