Decreased intestinal acetylcholinesterase in early Parkinson disease

Objective: To investigate systemic levels of acetylcholinesterase in early Parkinson disease (PD) with ¹¹C-donepezil PET, a potential marker of parasympathetic innervation. Methods: This was a cross-sectional study with 19 patients with early-stage PD (disease duration 1.5 ± 0.6 years) and 16 age-matched controls who had clinical assessments, olfaction tests, and ¹¹C-donepezil PET to measure acetylcholinesterase density in peripheral organs. Results: The patients with PD showed significantly reduced ¹¹C-donepezil uptake in the small intestine (−14%, p = 0.018), colon (−22%, p < 0.001), and kidneys (−14%, p = 0.028). No difference in myocardial or pancreatic acetylcholinesterase levels was seen. Conclusion: We found significantly decreased ¹¹C-donepezil signal in the intestine and kidneys of patients with early PD, suggesting that parasympathetic denervation is present early in the disease course.