Parkinson's disease with anxiety: clinical characteristics and their correlation with oxidative stress, inflammation, and pathological proteins.

OBJECTIVE

This study was performed to explore the differences in the clinical characteristics and oxidative stress indicators, inflammatory factors, and pathological proteins in serum between Parkinson's disease (PD) with anxiety (PD-A) and with no anxiety (PD-NA) patients, and further correlations among clinical characteristics and above variables were analyzed in PD-A and PD-NA groups.

METHODS

A total of 121 patients with PD were enrolled in this study and assessed by the Hamilton Anxiety Scale (14 items) (HAMA-14). These patients were divided into PD-A and PD-NA groups according to a cut-off point of 7 of HAMA-14. Demographic variables were collected, and clinical symptoms were assessed by multiple rating scales. The levels of free radicals, inflammatory factors, and pathological proteins in serum were measured by chemical colorimetric method and enzyme-linked immunosorbent assay (ELISA). The differences of above variables were compared between PD-A and PD-NA groups, and the correlations of clinical symptoms with the abovevariables were analyzed in PD-A and PD-NA groups.

RESULTS

The frequency of PD-A was 62.81%. PD-A group exhibited significantly impaired motor dysfunction and multiple non-motor symptoms, including fatigue, sleep behavior disorder, restless leg syndrome and autonomic dysfunction, and dramatically compromised activities of daily living compard with PD-NA group. PD-A group displayed prominently increasedlevels of hydroxyl radical (·OH) and tumor necrosis factor (TNF)-α, and a decreased nitric oxide (NO) level in serum compared with PD-NA group (P<0.001, P = 0.001, P= 0.027, respectively). ·OH, NO, and TNF-α were identified as the risk factors of PD-A (OR = 1.005, P = 0.036; OR = 0.956, P = 0.017; OR = 1.039, P = 0.033, respectively). In PD patients, HAMA-14 score was significantly and positively correlated with the levels of ·OH and TNF-α in serum (P<0.001, P = 0.002, respectively). In PD-A group, ·OH level was significantly and negatively correlated with Aβ level, while TNF-α level was significantly and positively correlated with P-tau (S396) level in serum.

CONCLUSIONS

The frequency of PD-A is high. PD-A patients present more severe motor dysfunction and multiple non-motor symptoms, and poorer activities of daily living. The increased levels of ·OH and TNF-α levels and the decreased NO level in serum are all associated with more severe anxiety in PD patients.Findings from this study may provide in-depth insights into the clinical characteristics, underlying mechanisms of PD-A, and potential correlations among anxiety, oxidative stress, inflammation, and cognitive decline in PD patients.