Fluid redox biomarkers in neurological disease

Redox imbalance is a common physiopathological feature in neurological disease, especially those with a relevant neurodegenerative component. The consequent damage to biomolecules leads to the generation of various relatively stable by-products, which can serve as biomarkers of oxidative stress. A wealth of epidemiological and clinical evidence has found an association between alteration of these fluid biomarkers and the occurrence of neurological diseases, in particular Alzheimer's disease (AD), vascular dementia (VD), and Parkinson's disease (PD). However, also conflicting results are reported. Herein, we systematically review the published data on this topic highlighting the methodological issues that hinder the definitive appreciation of the use of redox biomarkers in the diagnosis and prediction of the above-mentioned disorders.