ABSTRACT
Amyloid ß (Aß) deposition in the brain is considered the initiating event in the progression of Alzheimer's disease (AD). Amyloid imaging is widely studied in diagnosing AD and evaluating the disease stage, with considerable advances achieved in recent years. We have developed a novel ¹9F-containing curcumin derivative (named FMeC1) as a potential imaging agent. This compound can exist in equilibrium between keto and enol tautomers, with the enol form able to bind Aß aggregates while the keto form cannot. This study investigated whether FMeC1 is suitable as a ¹9F magnetic resonance imaging (MRI) probe to detect Aß deposition in the Tg2576 mouse, a model of AD. In ¹9F nuclear magnetic resonance (NMR) spectra obtained from the whole head, a delayed decreased rate of F ¹9F signal was observed in Tg2576 mice that were peripherally injected with FMeC1 in comparison to wild-type mice. Furthermore, ¹9F MRI displayed remarkable levels of ¹9F signal in the brain of Tg2576 mice after the injection of FMeC1. Histological analysis of FMeC1-injected mouse brain showed penetration of the compound across the blood-brain barrier and binding to Aß plaques in peripherally injected Tg2576 mice. Moreover, the distribution of Aß deposits in Tg2576 mice was in accordance with the region of the brain in which the ¹9F signal was imaged. FMeC1 also exhibited an affinity for senile plaques in human brain sections. These findings suggest the usefulness of FMeC1 as a ¹9F MRI probe for the detection of amyloid deposition in the brain. Furthermore, the properties of FMeC1 could form the basis for further novel amyloid imaging probes.
