Evidence for astrocytosis in ALS demonstrated by [11C](L)-deprenyl-D2 PET.

OBJECTIVE: To use deuterium-substituted [11C](L)-deprenyl PET to depict astrocytosis in vivo in patients with amyotrophic lateral sclerosis (ALS). BACKGROUND: In human brain, the enzyme MAO-B is primarily located in astrocytes. L-deprenyl binds to MAO-B and autoradiography with 3H-L-deprenyl has been used to map astrocytosis in vitro. Motor neuron loss in ALS is accompanied by astrocytosis and astrocytes may play an active role in the neurodegenerative process. Deuterium-substituted [11C](L)-deprenyl PET provides an opportunity to localize astrocytosis in vivo in the brain of patients with ALS. METHODS: Deuterium-substituted [11C](L)-deprenyl PET was performed in seven patients with ALS and seven healthy control subjects. RESULTS: Increased uptake rate of [11C](L)-deprenyl was demonstrated in ALS in pons and white matter. CONCLUSION: This study provides evidence that astrocytosis may be detected in vivo in ALS by the use of deuterium-substituted [11C](L)-deprenyl PET though further studies are needed to determine whether deuterium-substituted [11C](L)-deprenyl binding tracks disease progression and reflects astrocytosis.