Gastrointestinal Dysfunction and Neuropathologic Correlations in Parkinson Disease

Recently, an increasing interest to nonmotor symptoms of Parkinson disease (PD) has shown. Gastrointestinal dysfunction is a prominent nonmotor manifestation of PD and precedes motor symptoms for several years. Neuropathologic studies show early accumulation of α-synuclein (α-SYN) in Lewy neurites and Lewy body in the enteric nervous system (ENS) and dorsal motor nucleus of the vagus in PD. Our study aims to investigate relationship between α-SYN deposition in ENS and gastrointestinal dysfunction in PD.

We conducted a study in Neurology Department of Charles Nicolle Hospital of Tunis during 2 years (2013 to 2014) including PD patients. Clinical data were analyzed. Digestive endoscopy with biopsies of upper digestive tract (UDT) and immunohistochemistry study were performed.

Thirty patients (16♂/14♀) and 13 (7♂/6♀) controls were included. Average age was 65 years for patients and 63.5 years for controls. Gastrointestinal symptoms were the most frequent nonmotor symptoms occurring in 73%. Endoscopy showed motor dysfunction of upper digestive tract in 5 patients. Lesion load in α-SYN was significantly correlated with frequency and severity of gastrointestinal dysfunction and PD motor disability.

Gastrointestinal disturbances are frequent in PD. ENS's synucleinopathy could entirely explain pathophysiology of digestive dysfunction and is correlated with severity of gastrointestinal symptoms in PD. Biopsies may show α-SYN aggregates in immunoreactive Lewy neurites in the submucosal and myenteric plexus. Thus, endoscopic and immunohistochemical exploration of ENS may be a biomarker for Parkinson enteropathy and for PD overall.