CRANAD-28: A Robust Fluorescent Compound for Visualization of Amyloid Beta Plaques.

ABSTRACT

CRANAD-28, a difluoroboron curcumin analogue, has been demonstrated in earlier reports to successfully label amyloid beta (Aß) plaques for imaging both ex vivo and in vivo. CRANAD-28's imaging brightness, ability to penetrate the blood brain barrier, and low toxicity make the compound a potentially potent imaging tool in Alzheimer's research. In this study, the Aß-labeling ability of CRANAD-28 was investigated in further detail using histological staining to assess different criteria, including stained Aß plaque brightness, Aß plaque size, and Aß plaque number count. The results of this study demonstrated CRANAD-28 to be superior across all criteria assessed. Furthermore, CRANAD-28 and IBA-1 antibody were used to label Aß-plaques and microglia respectively. Statistical analysis with Spearman regression revealed a statistically significant negative correlation between the size of labeled Aß plaques and surrounding microglia density. This finding provides interesting insight into Aß plaque and microglia dynamism in AD pathology and corroborates the findings of previous studies. In addition, we found that CRANAD-28 provided distinct spectral signatures for Aßs in the core and periphery of the plaques. Based on the study's results, CRANAD-28 could be considered as an alternative standard for imaging Aß-plaques in future research studies.