Affiliations: [a] Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, Germany | [b] Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany | [c] Division of Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Medical Center Göttingen (UMG), Germany | [d] Department of Neuropathology and Tissue Bank, Fundación CIEN, Instituto de Salud Carlos III, Madrid, Spain | [e] Department of Psychiatry, University Medical Center Göttingen, Germany | [f] German Center for Neurodegenerative Diseases, DZNE, Göttingen, Germany
Correspondence:
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Correspondence to: Anja Schneider, Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany. Tel.: +49 551 39 6611; Fax: +49 551 39 12346; aschnei8@gwdg.de
Correspondence:
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Correspondence to: Silvio O. Rizzoli, Department of Neuro- and Sensory Physiology, University Medical Center
Göttingen, Germany. Tel.: +49 551 39 33630; Fax: +49 551 39 12346;E-mail: srizzol@gwdg.de
Abstract: Alzheimer’s disease (AD) is neuropathologically characterized by aggregates of amyloid-β peptides (Aβ) and tau proteins. The consensus in the AD field is that Aβ and tau should serve as diagnostic biomarkers for AD. However, their aggregates have been difficult to investigate by conventional fluorescence microscopy, since their size is below the diffraction limit (∼200 nm). To solve this, we turned to a super-resolution imaging technique, stimulated emission depletion (STED) microscopy, which has a high enough precision to allow the discrimination of low- and high-molecular weight aggregates prepared in vitro. We used STED to analyze the structural organization of Aβ and tau in cerebrospinal fluid (CSF) from 36 AD patients, 11 patients with mild cognitive impairment (MCI), and 21 controls. We measured the numbers of aggregates in the CSF samples, and the aggregate sizes and intensities. These parameters enabled us to distinguish AD patients from controls with a specificity of ∼87% and a sensitivity of ∼79% . In addition, the aggregate parameters determined with STED microscopy correlated with the severity of cognitive impairment in AD patients. Finally, these parameters may be useful as predictive tools for MCI cases. The STED parameters of two MCI patients who developed AD during the course of the study, as well as of MCI patients whose Aβ ELISA values fall within the accepted range for AD, placed them close to the AD averages. We suggest that super-resolution imaging is a promising tool for AD diagnostics.
Keywords: Alzheimer’s disease, amyloid-β, diagnostics, imaging, super-resolution, tau
