Circulating biochemical signatures of neurodegeneration in Alzheimer's disease.

Alzheimer's Disease (AD), a major cause of progressive memory loss, is pathogenically associated with the accumulation of amyloid-beta (Aβ) plaques, tau-mediated neurofibrillary tangles, neuroinflammation, and neurodegeneration. The molecular, biochemical and cellular malformation apears to occur before the onset of behavioural symptoms and intensifies as the disease progresses, highlighting the importance of early diagnostic approaches. The routine neuroimaging-based techniques, such as magnetic resonance imaging and positron emission tomography, are highly valuable to monitor the emergence of symptoms but are limited by high cost and accessibility. The cerebrospinal fluid-based methods provide valuable insight into the state of disease, however the procedure associated with sample collection is highly invasive. Eventually, the blood-based biomarkers have emerged as a promising and minimally invasive alternative procedure for the detection and monitoring of AD. The circulating biomarkers such as Aβ , phosphorylated tau isoforms, and associated abnormal biochemical signatures are correlated with pathological processes in AD. Assessing these blood biomarkers is not only crucial for diagnostics but also important for monitoring the changes associated with treatment in AD. As most current treatment options provide only symptomatic relief, advanced diagnostic approaches are essential for early detection and therapeutic intervention. The blood-based biomarkers represent a transformative step toward early diagnosis, large-scale screening, and precision medicine in AD, with significant potential for the development of disease-modifying therapies. Thus, this book chapter provides an overview of blood-based biomarker panels and discusses recent advances in bioanalytical technologies in AD.