Details

Autor(en) / Beteiligte

• Gulyás, Balázs
• Spenger, Christian
• Beliczai, Zsuzsa
• Gulya, Károly
• Kása, Péter
• Jahan, Mahabuba
• Jia, Zhisheng
• Weber, Urs
• Pfeifer, Andrea
• Muhs, Andreas
• Willbold, Dieter
• Halldin, Christer

Titel

Distribution and binding of 18F-labeled and 125I-labeled analogues of ACI-80, a prospective molecular imaging biomarker of disease: A whole hemisphere post mortem autoradiography study in human brains obtained from Alzheimer’s disease patients

Ist Teil von

• Neurochemistry international, 2012-01, Vol.60 (2), p.153-162

Ort / Verlag

Kidlington: Elsevier Ltd

Erscheinungsjahr

2012

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• ► We lack molecular imaging biomarkers for the in vivo diagnostic in Alzheimer’s disease (AD). ► Recently a dodecamer peptide (ACI-80) was identified as a prospective ligand binding to amyloid. ► We tested [125I] and [18F] labeled ACI-80 in post mortem human brain autoradiography (ARG) experiments. ► ARG in AD brains demonstrates the amyloid visualization capacity of radiolabeled ACI-80 analogues. ► Radiolabeled ACI-80 analogues are prospective molecular imaging biomarkers of amyloid in AD. One of the major pathological landmarks of Alzheimer’s disease and other neurodegenerative diseases is the presence of amyloid deposits in the brain. The early non-invasive visualization of amyloid is a major objective of recent diagnostic neuroimaging approaches, including positron emission tomography (PET), with an eye on follow-up of disease progression and/or therapy efficacy. The development of molecular imaging biomarkers with binding affinity to amyloid in the brain is therefore in the forefront of imaging biomarker and radiochemistry research. Recently, a dodecamer peptide (amino acid sequence=QSHYRHISPAQV; denominated D1 or ACI-80) was identified as a prospective ligand candidate, binding with high ex vivo affinity to L-Aβ-amyloid (Kd: 0.4μM). In order to assess the ligand’s capacity to visualize amyloid in Alzheimer’s disease (AD), two 125I labeled and three 18F labeled analogues of the peptide were synthesized and tested in post mortem human autoradiography experiments using whole hemisphere brain slices obtained from deceased AD patients and age matched control subjects. The 18F-labeled radioligands showed more promising visualization capacity of amyloid that the 125I-labeled radioligands. In the case of each 18F radioligands the grey matter uptake in the AD brains was significantly higher than that in control brains. Furthermore, the grey matter: white matter uptake ratio was over ∼2, the difference being significant for each 18F-radioligands. The regional distribution of the uptake of the various radioligands systematically shows a congruent pattern between the high uptake regions and spots in the autoradiographic images and the disease specific signals obtained in adjacent or identical brain slices labeled with histological, immunohistochemical or autoradiographic stains for amyloid deposits or activated astrocytes. The present data, using post mortem human brain autoradiography in whole hemisphere human brains obtained from deceased AD patients and age matched control subjects, support the visualization capacity of the radiolabeled ACI-80 analogues of amyloid deposits in the human brain. Further studies are warranted to explore the usefulness of the 18F-labeled analogues as in vivo molecular imaging biomarkers in diagnostic PET studies.