AUTHOR=Santin Mathieu D. , Vandenberghe Michel E. , Herard Anne-Sophie , Pradier Laurent , Cohen Caroline , Debeir Thomas , Delzescaux Thierry , Rooney Thomas , Dhenain Marc TITLE=In Vivo Detection of Amyloid Plaques by Gadolinium-Stained MRI Can Be Used to Demonstrate the Efficacy of an Anti-amyloid Immunotherapy JOURNAL=Frontiers in Aging Neuroscience VOLUME=Volume 8 - 2016 YEAR=2016 URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2016.00055 DOI=10.3389/fnagi.2016.00055 ISSN=1663-4365 ABSTRACT=

Extracellular deposition of β amyloid plaques is an early event associated to Alzheimer’s disease. Here, we have used in vivo gadolinium-stained high resolution (29∗29∗117 μm3) magnetic resonance imaging (MRI) to follow-up in a longitudinal way individual amyloid plaques in APP/PS1 mice and evaluate the efficacy of a new immunotherapy (SAR255952) directed against protofibrillar and fibrillary forms of Aβ. APP/PS1 mice were treated for 5 months between the age of 3.5 and 8.5 months. SAR255952 reduced amyloid load in 8.5-months-old animals, but not in 5.5-months animals compared to mice treated with a control antibody (DM4). Histological evaluation confirmed the reduction of amyloid load and revealed a lower density of amyloid plaques in 8.5-months SAR255952-treated animals. The longitudinal follow-up of individual amyloid plaques by MRI revealed that plaques that were visible at 5.5 months were still visible at 8.5 months in both SAR255952 and DM4-treated mice. This suggests that the amyloid load reduction induced by SAR255952 is related to a slowing down in the formation of new plaques rather than to the clearance of already formed plaques.