Cerebral amyloid deposition and serotoninergic innervation in Parkinson disease

BACKGROUND Prior studies suggest that serotoninergic neurotransmission reduces β-amyloid (Aβ) production. OBJECTIVE To determine whether serotoninergic system degeneration in Parkinson disease promotes Aβ deposition, using in vivo positron emission tomographic probes of serotonin system integrity and Aβ deposition. DESIGN, SETTING, AND PATIENTS Cross-sectional study of 13 subjects with Parkinson disease from the movement disorders clinics at the University of Michigan Health System and Veterans Affairs Ann Arbor Healthcare System, with positron emission tomography using the serotonin transporter ligand carbon 11 ([11C])-labeled 3-amino-4-(2-dimethylaminomethyl-phenylsulfaryl)-benzonitrile (DASB) and the Aβ ligand [11C]Pittsburgh compound B. RESULTS Inverse correlations were found between DASB and Pittsburgh compound B distribution volume ratios in the neocortex (ρ = -0.577; P = .04) and striatum (ρ = -0.780; P = .002). CONCLUSION Serotoninergic system degeneration in Parkinson disease may promote the development of cerebral amyloidopathy.