Fluid Biomarkers Indicative of Neurodegenerative Diseases

A major unifying feature of neurodegenerative diseases (NDDs) is excessive neuronal loss. Depending on when and where this occurs, patients may express distinct neurological and psychiatric symptoms. Neurodegeneration is accompanied by protein aggregation, inflammation, and microglial activation that may be drivers of the disease or in some circumstances may be protective reactions to the neurodegenerative process. A key development over the past decade has been our ability to leverage these accompanying central nervous system changes to develop clinically impactful biomarkers of specific NDDs. This has been crucial in helping us develop an understanding the time line of progression of these diseases, in their early diagnosis and to help target patients appropriately in therapeutic clinical trials, This chapter gives an overview of both established and novel fluid biomarkers for neurodegeneration, protein accumulation, inflammation, and microglial activation across different neurodegenerative diseases. Common as well as disease-specific biomarker changes in cerebrospinal fluid and blood are emphasized.