Clinical proteomics of the cerebrospinal fluid: Towards the discovery of new biomarkers

The cerebrospinal fluid (CSF) circulates within the CNS where it plays an essential physiological role in homeostasis of neuronal cells. This biological fluid has an important protein diversity that results from both filtration of serum through the blood-brain barrier and production/secretion of neuronal peptides and proteins. Changes in CSF composition depend on blood proteome, CSF circulation alterations, as well as physiological or pathological brain status. Hence, CSF proteomic analysis gives a unique opportunity to detect and describe biomarkers in neurological affections. Although lumbar puncture is considered as invasive, post lumbar puncture events remain rare and minor. Nevertheless, CSF biological analysis is currently limited to a small number of parameters and clinical situations suggesting mainly meningitis, malignancies or dementia. Few CSF proteomic studies have been performed in comparison to those on blood. In this review, we will provide a proteomics description of the CSF, summarize the current clinical use of this fluid and describe its clinical proteomics examination.