Cerebrospinal fluid biomarkers in Alzheimer's disease

Over the past years, the diagnosis of Alzheimer' disease (AD) has been largely improved by the discovery and the use of cerebrospinal fluid (CSF) and imaging biomarkers. Conventional CSF biomarkers, now widely known, revealed a decreased concentration of the amyloid peptide A beta 1-42 and increased levels of tau and phosphorylated tau proteins. Some of these CSF biomarkers can be abnormal one or two decades before the onset of the first clinical symptoms. They are able to predict the conversion from a mild cognitive impairment to a severe cognitive impairment and they are well correlated with imaging makers such as amyloid PET imaging. The new CSF biomarkers have been developed to assess the magnitude of synaptic demise and neuronal death as well as neuroinflammation. The initial results have shown that they are correlated with the cognitive decline of the patients. In the future, the detection of the early metabolic brain anomalies could allow a new secondary preventive approach of AD. In addition it could facilitate inclusion in clinical trials in which therapeutic targeting and action on neurodegenerative parameters might be validated over the evolution.