Purpose
The aim of the present study was to compare amyloid-β (Aβ) deposition, translocator protein (TSPO) activity, regional cerebral metabolic rate of glucose (rCMRglc), and mitochondrial complex I (MC-I) activity in the brain of aged monkeys.
Methods
PET scans with 11C-PIB (Aβ), 18F-BCPP-EF (MC-I), 11C-DPA-713 (TSPO), and 18F-FDG (rCMRglc) were performed in aged monkeys (Macaca mulatta) in the conscious state and under isoflurane anaesthesia. 11C-PIB binding to Aβ and 11C-DPA-713 binding to TSPO were evaluated in terms of standard uptake values (SUV). The total volume of distribution (V T) of 18F-BCPP-EF and rCMRglc with 18F-FDG were calculated using arterial blood sampling.
Results
Isoflurane did not affect MC-I activity measured in terms of 18F-BCPP-EF uptake in living brain. There was a significant negative correlation between 18F-BCPP-EF binding (V T) and 11C-PIB uptake (SUVR), and there was a significant positive correlation between 11C-DPA-713 uptake (SUV) and 11C-PIB uptake. In contrast, there was no significant correlation between rCMRglc ratio and 11C-PIB uptake.
Conclusion
18F-BCPP-EF could be a potential PET probe for quantitative imaging of impaired MC-I activity that is correlated with Aβ deposition in the living brain.