Applicability of [11C]PIB micro-PET imaging for in vivo follow-up of anti-amyloid treatment effects in APP23 mouse model

In this study, we evaluated the anti-amyloid effect of functionalized nanoliposomes (mApoE-PA-LIP) in a mouse model of Alzheimer's disease with use of positron emission tomography and beta-amyloid (A beta) etargeted tracer [C-11] Pittsburgh compound B ([C-11] PIB). APP23 mice were injected with mApoE-PALIP or saline (3 times per week for 3 weeks) and [C-11] PIB imaging was performed at baseline, after the treatment and after 3 months follow-up period, accompanied by Ab immunohistochemistry and ELISA. After the treatment, [C-11] PIB binding ratios between mApoE-PA-LIP and saline groups were equivalent in all analyzed brain regions; however, in the saline group, binding ratios increased from the baseline, whereas no increase was detected in the mApoE-PA-LIP group. During the additional follow-up, [C-11] PIB binding increased significantly from baseline in both groups, and binding ratios correlated with the immunohistochemically defined A beta load. This study further supports the use of [C-11] PIB positron emission tomography imaging as a biomarker of A beta deposition in APP23 mice and highlights the benefits of noninvasive follow-up, that is, using baseline data for animal stratification and normalization of treatment effects to baseline values, for future anti-amyloid treatment studies. (C) 2017 The Authors. Published by Elsevier Inc.