Parkinson's disease is associated with oxidative stress: comparison of peripheral antioxidant profiles in living Parkinson's, Alzheimer's and vascular dementia patients.

Antioxidant profiles in Parkinson's disease (PD; n = 15), dementias of Alzheimer's type (DAT; 18) and Vascular (VD; 15), and control subjects (C; 14) were studied. Cu-Zn superoxide dismutase (SOD), catalase (CAT), glutathione system (GLU) and thiobarbituric acid reactive substances (TBARS) were measured in erythrocytes; antioxidant capacity (TRAP) in plasma. Biochemical variables were analyzed simultaneously using multi-variate and non-parametric methods. Clinical diagnostic resulted associated with the main source of variability in antioxidant variables (Kruskal-Wallis: H = 32.58, p = 0.000001). Comparison of PD and C resulted highly significant (z = 4.47, p = 0.000047), demonstrating an association between oxidative stress and PD. SOD and TBARS were significantly higher in pathological groups against C (p = 0.0000001, p = 0.051); TRAP resulted lower (p = 0.00015). Discriminant functions constructed using biochemical variables separated pathological groups (93% success) from C, and DAT (88.9%) from VD (73.3%); but not PD from DAT or VD. Antioxidant profiles of PD patients showed characteristics overlapping with DAT (60%) and with VD (40%), suggesting biochemical similarities between them.