Early Detection of Amyloid Plaques in Mouse Models of Alzheimer’s Disease by PET with 18F-Hydroxy Quinoline

Goal of the study was to evaluate 18F-(8-hydroxy) quinoline (18F-HOQ) by PET in transgenic (Tg) animal models of Alzheimer’s disease (AD). Five groups of mice (n=4 per group) were used; control (WT, 12 mo), APP/PS Tg mice (4, 6, and 12 mo) and APOE4 Tg mice (12 mo). 18F-HOQ was prepared as previously reported by us. Animals were imaged in a PET/CT scanner for 30 minutes immediately after intravenous injection of the tracer and SUV values for various brain regions determined. After imaging, animal brain sections were stained and amyloid plaque burden measured. Cortex, olfactory bulbs and hippocampus had higher activity compared to cerebellum and were significantly higher (p<0.05) in APP/PS1 Tg mice compared to WT or APOE4 mice. Only APP/PS1 mice brain sections were positive for Aβ. Tracer uptake by PET correlated with plaque density measured by histopathology. Plaque density increased with age. Differences in brain uptake by PET could be observed at an early age (4 mo) only in APP/PS1 mice. F-18 HOQ may be useful in monitoring the progression of Aβ plaque deposition in suitable AD animal models by PET and in assessing efficacy of therapeutic agents aimed at reduction of amyloid plaque burden.