Yes, cerebrospinal fluid (CSF) is indeed a biomarker.
CSF contains various proteins and other substances that can be measured to detect and monitor different conditions, particularly neurological disorders. The levels of these substances in CSF can indicate the presence, severity, or progression of a disease.
CSF Biomarkers in Alzheimer's Disease
A well-studied example is the use of CSF biomarkers in the diagnosis and prediction of Alzheimer's disease (AD). Key CSF biomarkers for AD include:
- Amyloid-beta 42 (Aβ42): Lower levels of Aβ42 in CSF often indicate amyloid plaque deposition in the brain, a hallmark of AD. Studies, such as the one by Mattsson et al. [21], have found that CSF Aβ42 can be a relatively accurate biomarker for identifying MCI patients who will convert to AD.
- Total tau (t-tau): Elevated levels of t-tau in CSF suggest neuronal damage and degeneration.
- Phosphorylated tau (p-tau): Elevated levels of p-tau in CSF are indicative of neurofibrillary tangles, another key pathological feature of AD.
The combination of these biomarkers, especially Aβ42 in comparison with t-tau and p-tau, improves the accuracy of diagnosing and predicting AD, as highlighted in Mattsson et al. [21].
Other Applications of CSF Biomarkers
Besides Alzheimer's disease, CSF biomarkers are also used in the diagnosis and monitoring of:
- Multiple sclerosis (MS)
- Infections of the central nervous system (e.g., meningitis, encephalitis)
- Brain tumors
- Other neurodegenerative diseases
The analysis of CSF can provide valuable insights into the biochemical and pathological processes occurring within the brain and spinal cord, making it a valuable tool for clinical diagnosis and research.
