Relationship of irisin with disease severity and dopamine uptake in Parkinson's disease patients

Background: This study was designed to investigate the relationship of irisin with the severity of Parkinson’s disease (PD) and dopamine (DOPA) uptake in patients with PD and to understand the role of irisin in PD and its potential value as a drug therapy. Methods: The plasma levels of irisin and α-syn were measured by ELISA. Motor and nonmotor symptoms were assessed with related scales. DOPA uptake was measured with DOPA PET/MRI. Results: : The plasma level of α-syn and irisin in patients with PD increased and decreased gradually with the progression of the disease, respectively. There was a negative correlation between plasma α-syn and irisin levels in patients with PD. The level of irisin in plasma was negatively correlated with UPDRS-III scores and positively correlated with MOCA scores. The SORs of the ipsilateral and contralateral caudate nucleus, anterior putamen and posterior putamen in the high-Irisin group was significantly higher than those in the low-Irisin group, and irisin levels in the caudate nucleus, anterior putamen, and posterior putamen contralateral to the affected limb were lower than those on the ipsilateral side. The level of irisin was positively correlated with the SORs of the ipsilateral and contralateral caudate nucleus and putamen in PD patients. Conclusions: : Irisin plays a neuroprotective role by decreasing the level of α-syn. Irisin is negatively correlated with the severity of motor symptoms and cognitive impairment. More importantly, irisin can improve DOPA uptake in the striatum of patients with PD, especially on the side contralateral to the affected limb.