Characteristics of systemic inflammation and brain iron deposition in Parkinson's disease patients

OBJECTIVE: This study aimed at determining the characteristics of systemic inflammation and brain iron deposition in Parkinson's disease (PD) patients. METHODS: Thirty two PD patients and 30 gender‐ as well as age‐matched controls were enrolled. Serum interleukin (IL)‐1β, IL‐33, tumor necrosis factor (TNF)‐α, IL‐6, IL‐10, ferritin, iron, and total iron binding capacity (TIBC) levels were assayed. Quantitative susceptibility mapping (QSM) was used to quantitatively analyze brain iron accumulation in the regions of interest (ROIs). Correlations between concentrations of inflammatory cytokines and biomarkers for peripheral iron metabolism, brain iron deposition were evaluated in the PD group. RESULTS: Serum concentrations of IL‐1β and IL‐33 were found to be significantly elevated in the PD group compared to the control group, and in early‐stage PD group compared to advanced‐stage PD group. Total QSM value for bilateral ROIs was significantly elevated in the PD group compared to the control group, and in advanced‐stage PD group compared to early‐stage PD group. There was a significant inverse correlation between serum IL‐1β concentration and total QSM value for bilateral ROIs, between serum ferritin, iron, TIBC concentrations, and total QSM value for bilateral ROIs in PD patients. However, there was no significant correlation between serum IL‐1β concentrations and serum ferritin, iron, TIBC concentrations in PD patients. INTERPRETATION: The inflammatory state and chronic brain iron deposition progression in PD patients might be asynchronous. Alterations in systemic inflammation were not correlated with peripheral iron metabolism and might not contribute to the aggravation of brain iron deposition in PD patients.