PET Imaging Shows the Brain's Cannabinoid System Changes Early in Alzheimer's, Differently in Males and Females

PET imaging revealed dynamic changes in cannabinoid receptor 1 (CB1) and MAGL enzyme availability across Alzheimer's disease progression. At 4 months (early-stage), female AD mice had lower CB1 availability while males had increased MAGL. By 12 months (late-stage), CB1 was significantly reduced in AD mice compared to controls. The pattern of changes was consistently sex-dependent throughout disease progression.

PET-CT imaging study using two radioligands ([18F]FMPEP-d2 for CB1 and [18F]MAGL-2102 for MAGL) in a knock-in Alzheimer's mouse model at 3 ages (4, 8, and 12 months). Findings were supplemented with autoradiography, immunofluorescence, and western blots.

The endocannabinoid system is a potential therapeutic target for Alzheimer's, but this study shows its changes are complex, varying by sex, age, and disease stage. This means cannabinoid-based therapies for Alzheimer's may need to be tailored to the patient's sex and disease stage to be effective.

Interest in cannabinoid-based Alzheimer's treatments has grown, but this study suggests a one-size-fits-all approach may not work. The endocannabinoid system changes differently in males and females with Alzheimer's, and the therapeutic window may be narrow. PET imaging could help monitor these changes and guide treatment timing.

Mouse model of Alzheimer's that may not fully recapitulate human disease. PET radioligand binding reflects availability, not necessarily function. Relatively small group sizes typical of PET imaging studies. Cannot directly translate timing of mouse disease stages to human disease progression.