Association of plasma neurofilament light chain and Lipoprotein-related phospholipase A2 with motor subtypes of Parkinson's disease

Neurofilament light chain (NfL) levels were reliable biomarkers of neurodegeneration in Parkinson's disease (PD). Lipoprotein-related Phospholipase A2(Lp-PLA2) levels have also been increasingly studied in PD. We aimed to explore the association of plasma NfL and Lp-PLA2 with the diagnosis, motor subtypes and disease severity of PD. Plasma NfL and Lp-PLA2 were assayed separately in 106 participants (74 PD and 32 healthy controls, HC). The motor subtypes of PD were classified according to the MDS-UPDRS components, and motor and non-motor manifestations of patients were also evaluated. Subsequently, correlation analyses were performed. The plasma NfL levels were higher in the PD than HC, and were positively correlated with age, UPDRS II, UPDRS III and the modified Hoehn and Yahr staging scale (H&Y stage) in the PD. Moreover, plasma Lp-PLA2 levels were lower in the PD than HC, and were positively correlated with Parkinson's Disease Quality of Life Questionnaire (PDQ-39) in the PD. For further distinguishing tremor-dominant (TD) from postural instability and gait difficulty-dominant (PIGD), plasma Lp-PLA2 levels were higher in the TD than PIGD, but there was no significant difference in NfL. plasma Lp-PLA2 levels were positively correlated with UPDRS I, Hamilton Anxiety Rating Scale (HAMA) and PDQ-39 in the TD. These results suggest that NfL and Lp-PLA2 may be potential biomarkers for the diagnosis of PD. We first demonstrated the potential utility of plasma Lp-PLA2 in differentiating motor subtypes. These findings deserve further evidence in larger PD cohorts.