Cerebrospinal Fluid C-Reactive Protein in Parkinson's Disease: Associations with Motor and Non-motor Symptoms

Parkinson' disease (PD) is characterized by motor symptoms including bradykinesia, resting tremor, postural instability, and rigidity and non-motor symptoms such as cognitive impairment, sleep disorder, and depression. Neuroinflammation has been recently implicated in pathophysiology of both motor and non-motor symptoms of PD. One of the most notable inflammatory proteins is C-reactive protein (CRP), which is elevated in the conditions of systemic inflammation. Using BioFIND database, we scrutinized the possible association between cerebrospinal fluid (CSF) levels of CRP and severity of PD motor and non-motor symptoms. Eighty-four healthy controls (HCs) and 109 PD subjects were entered into this study. A significant correlation was observed between CSF CRP levels and Movement Disorder Society-Unified Parkinson's Disease Rating Scale Part III (MDS-UPDRS part III) score and Montreal Cognitive Assessment (MoCA) score in PD patients. We found significant correlations between MoCA score and CSF CRP levels in female patients and between CSF CRP and MDS-UPDRS part III score and MoCA score in male patients. In linear regression, CSF CRP could predict 6.9 and 10% of changes in MDS-UPDRS part III score in all PD patients male PD patients, respectively. In summary, we confirmed that CSF concentrations of CRP are in correlation with motor and non-motor severity in PD subjects. Our findings suggest that neuroinflammation plays an important role in the initiation and probably progression of PD motor and non-motor symptoms, which may give us a better insight into the underlying pathologic mechanisms in PD.