Nitric oxide and peroxynitrite serum levels in Parkinson's disease: correlation of oxidative stress and the severity of the disease

Abstract

Background: Nitric oxide (NO) and its toxic product peroxynitrite contribute to oxidative stress and neurodegeneration in Parkinson's disease (PD). The relationship of serum levels of these oxidants with the severity of the disease [evaluated by the Unified Parkinson's Disease Rating Scale (UPDRS)] is not established.

Aim: This study was designed to evaluate whether patients with PD had higher NO and peroxynitrite serum level or not.

Patients and methods: Fifty eight patients with PD and 15 healthy volunteers entered this study. The concentrations of serum NO and peroxynitrite were assayed and their correlation with the UPDRS score was assessed.

Results: Mean serum NO levels in patient group was 29.8 ± 21.631 versus 7.49 ± 2.573 in control group, which was significantly higher in patients (p ≤ 0.0001). Peroxynitrite levels in patient and control groups were 7.37±3.501 µmol/L and 3.94 ±1.389 µmol/L respectively. Patients had a significantly higher peroxynitrite level (p = 0.0004).

Conclusions: Higher levels of NO and peroxynitrite leads to higher UPDRS scores. It seems since current PD treatments do not affect the pathology of the disease, using drugs that exert neuroprotective properties should be considered for the treatment of PD in order to prevent further neuronal cell loss.