florbenazine-f-18 and Parkinsonian-Disorders

Idiopathic Parkinson disease is a common neurodegenerative disorder for which misdiagnosis occurs in up to 30% of patients after initial assessment and in 10%-15% even after long-term follow-up. Vesicular monoamine transporter type 2 (VMAT2) imaging with PET allows assessment of the integrity of the presynaptic dopaminergic pathway. We investigated the management impact of VMAT2 imaging in patients with clinically uncertain Parkinsonian syndromes.

Topics: Adult; Aged; Aged, 80 and over; Antiparkinson Agents; Brain; Brain Chemistry; Case Management; Female; Fluorine Radioisotopes; Humans; Image Processing, Computer-Assisted; Male; Middle Aged; Molecular Imaging; Neuroimaging; Parkinsonian Disorders; Positron-Emission Tomography; Radiopharmaceuticals; Tetrabenazine; Vesicular Monoamine Transport Proteins; Young Adult

The 1-methyl-4-phenyl-1,2,3,4-tetrahydropyridine (MPTP)-induced parkinsonism model, particularly in non-human primates, remains the gold-standard for studying the pathogenesis and assessing novel therapies for Parkinson's disease. However, whether the loss of dopaminergic neurons in this model is progressive remains controversial, mostly due to the lack of objective in vivo assessment of changes in the integrity of these neurons. In the present study, parkinsonism was induced in cynomolgus monkeys by intravenous administration of MPTP (0.2 mg/kg) for 15 days; stable parkinsonism developed over 90 days, when the symptoms were stable. Noninvasive positron emission tomographic neuroimaging of vesicular monoamine transporter 2 with 9-[(18)F] fluoropropyl-(+)-dihydrotetrabenazine ([(18)F]AV-133) was used before, and 15 and 90 days after the beginning of acute MPTP treatment. The imaging showed evident progressive loss of striatal uptake of [(18)F]AV-133. The dopaminergic denervation severity had a significant linear correlation with the clinical rating scores and the bradykinesia subscores. These findings demonstrated that [(18)F]AV-133 PET imaging is a useful tool to noninvasively evaluate the evolution of monoaminergic terminal loss in a monkey model of MPTP-induced parkinsonism.

Topics: Animals; Corpus Striatum; Disease Models, Animal; Dopamine; Female; Fluorine Radioisotopes; Linear Models; Macaca fascicularis; Male; Parkinsonian Disorders; Positron-Emission Tomography; Severity of Illness Index; Tetrabenazine; Time Factors; Vesicular Monoamine Transport Proteins