Associations among Cognitive Functions, Plasma DNA, and Diffusion tensor image along the perivascular space (DTI-ALPS) in Patients with Parkinson's Disease
Abstract Background Parkinson’s disease (PD) is a common neurodegenerative disease associated with accumulation of misfolding proteins and increased neuroinflammation. The purpose of this study was to utilize diffusion tensor image analysis along the perivascular space (DTI-ALPS) to evaluate glymphatic system activity, and its relationship with systemic oxidative stress status in PD patients. Methods Magnetic resonance imaging and neuropsychological tests were conducted on 25 PD patients with normal cognition (PDN), 25 PD patients with mild cognitive impairment (PD-MCI), 38 PD patients with dementia (PDD), and 47 normal controls (NC). Oxidative stress status was assessed by plasma DNA level. Differences in ALPS-index among the subgroups were assessed and further correlated with cognitive functions and plasma DNA levels. Results The PD-MCI and PDD groups showed significantly lower ALPS-index compared to normal controls. The lower ALPS-index was correlated with higher plasma nuclear DNA, mitochondrial DNA levels, and lower cognitive scores. Conclusions Lower diffusivity along the perivascular space, represented by lower ALPS-index, indicates impairment of the glymphatic system in PD patients. The correlation between elevated plasma nuclear DNA levels and lower ALPS-index support the notion that PD patients may exhibit increased oxidative stress associated with glymphatic system microstructural alterations.