The emerging landscape of circulatory biomarkers in Alzheimer's disease.

Early detection of dementia remains a critical challenge for both researchers and clinicians. Blood-based biomarkers have emerged as a primary focus because they are less expensive and more scalable than neuroimaging or cerebrospinal fluid (CSF) analysis. Blood-based biomarkers offer a tool for screening, diagnosis, risk assessment, and therapeutic development. For clinical approval, biomarkers must be accessible, affordable, and minimally invasive. Inflammation, oxidative stress and mitochondrial dysfunction are the key events responsible for the initiation of formation of disease hallmarks, i.e., Aβ and pTau. This chapter explores the pathophysiology of Alzheimer's Disease (AD) to identify peripheral molecular markers associated with these early events and facilitate the development of combinatorial therapies. Shifting the focus from traditional cross-sectional neuroimaging towards cost-effective, longitudinal blood-based panels represents a vital step in managing the global burden of AD.