Potential oxidative stress biomarkers of mild cognitive impairment due to Alzheimer disease

The high and increasing incidence of Alzheimer Disease (AD) worldwide is a major global concern. Classical diagnosis is carried out in the dementia phase, often in the moderate stages when treatment efficacy is limited. Nowadays, early diagnosis, even in pre-dementia stages, is possible in selected cases within an appropriate clinical setting, employing cerebral spinal fluid (CSF) sample analysis and neuroimaging procedures. In spite of the accurate diagnosis achieved by novel CSF biomarkers or positron emission tomography beta-amyloid tracers, these tests are invasive and expensive. Therefore, important work is being carried out to discover reliable biomarkers in peripheral biofluids (blood, plasma, urine) to be incorporated in clinical routine for early AD diagnosis. Although the nature of AD pathogenesis is complex, it is known that oxidative stress plays a key role, for which biomarkers are easily determined in peripheral biofluids. This review summarizes recent research on oxidative stress biomarkers in mild cognitive impairment due to AD. Among them, a promising research line is the study of the relationship between lipid peroxidation biomarkers and early AD clinical features. Results show a pronounced imbalance between scientific production and clinical reality due to the lack of clinical validation. We conclude that an important field in oxidative stress biomarkers could be developed with the aim to help clinicians in early disease diagnosis, effective treatment initiation and reliable disease monitoring.