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- Carlred, Louise M, 1985, et al.
(author)
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Simultaneous imaging of amyloid-β and lipids in brain tissue using antibody-coupled liposomes and time-of-flight secondary ion mass spectrometry
- 2014
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In: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 136:28, s. 9973-9981
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Journal article (peer-reviewed)abstract
- The spatial localization of amyloid-β peptide deposits, the major component of senile plaques in Alzheimer's disease (AD), was mapped in transgenic AD mouse brains using time-of-flight secondary ion mass spectrometry (ToF-SIMS), simultaneously with several endogenous molecules that cannot be mapped using conventional immunohistochemistry imaging, including phospholipids, cholesterol and sulfatides. Whereas the endogenous lipids were detected directly, the amyloid-β deposits, which cannot be detected as intact entities with ToF-SIMS because of extensive ion-induced fragmentation, were identified by specific binding of deuterated liposomes to antibodies directed against amyloid-β. Comparative investigation of the amyloid-β deposits using conventional immunohistochemistry and fluorescence microscopy suggests similar sensitivity but a more surface-confined identification due to the shallow penetration depth of the ToF-SIMS signal. The recorded ToF-SIMS images thus display the localization of lipids and amyloid-β in a narrow (∼10 nm) two-dimensional plane at the tissue surface. As compared to a frozen nontreated tissue sample, the liposome preparation protocol generally increased the signal intensity of endogenous lipids, likely caused by matrix effects associated with the removal of salts, but no severe effects on the tissue integrity and the spatial distribution of lipids were observed with ToF-SIMS or scanning electron microscopy (SEM). This method may provide an important extension to conventional tissue imaging techniques to investigate the complex interplay of different kinds of molecules in neurodegenerative diseases, in the same specimen. However, limitations in target accessibility of the liposomes as well as unspecific binding need further consideration. © 2014 American Chemical Society.
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| 2. |
- Solé-Domènech, Santiago, et al.
(author)
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Localization of cholesterol, amyloid and glia in Alzheimer's disease transgenic mouse brain tissue using time-of-flight secondary ion mass spectrometry (ToF-SIMS) and immunofluorescence imaging
- 2013
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In: Acta Neuropathologica. - : Springer Science and Business Media LLC. - 0001-6322 .- 1432-0533. ; 125:1, s. 145-157
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Journal article (peer-reviewed)abstract
- The spatial distributions of lipids, amyloid-beta deposits, markers of neurons and glial cells were imaged, at submicrometer lateral resolution, in brain structures of a mouse model of Alzheimer's disease using a new methodology that combines time-of-flight secondary ion mass spectrometry (ToF-SIMS) and confocal fluorescence microscopy. The technology, which enabled us to simultaneously image the lipid and glial cell distributions in Tg2576 mouse brain structures, revealed micrometer-sized cholesterol accumulations in hippocampal regions undergoing amyloid-beta deposition. Such cholesterol granules were either associated with individual amyloid deposits or spread over entire regions undergoing amyloidogenesis. Subsequent immunohistochemical analysis of the same brain regions showed increased microglial and astrocytic immunoreactivity associated with the amyloid deposits, as expected from previous studies, but did not reveal any particular astrocytic or microglial feature correlated with cholesterol granulation. However, dystrophic neurites as well as presynaptic vesicles presented a distribution similar to that of cholesterol granules in regions undergoing amyloid-beta accumulation, thus indicating that these neuronal endpoints may retain cholesterol in areas with lesions. In conclusion, the present study provides evidence for an altered cholesterol distribution near amyloid deposits that would have been missed by several other lipid analysis methods, and opens for the possibility to study in detail the putative liaison between lipid environment and protein structure and function in Alzheimer's disease.
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