Neuron specific enolase in cerebrospinal fluid: a biochemical marker for neuronal degeneration in dementia disorders?

Alzheimer's disease (AD) is the most common disease causing dementia. Today the clinical diagnosis of AD is made by way of exclusion, and no biochemical markers are available to assist the clinical diagnosis. We examined the potential of neuron-specific enolase (NSE) in cerebrospinal fluid (CSF) as a diagnostic marker for AD. NSE was determined with a monoclonal antibody two-site immunoradiometric assay (IRMA) in serum (S) and cerebrospinal fluid (CSF) samples from 45 patients with "probable Alzheimer's disease (AD)", 19 patients with vascular dementia (VAD) and 33 age-matched healthy individuals. There was no significant correlation between S-NSE and CSF-NSE, or between CSF/S albumin ratio and CSF-NSE, findings suggesting that the major portion of CSF-NSE is intrathecally produced and that analysis of CSF-NSE alone (without accompanying analysis of serum) is sufficient. CSF-NSE was significantly higher in the AD group (4.7 +/- 2.7 ng/mL; p < 0.0001) and in VAD group (4.5 +/- 2.5 ng/mL; p < 0.001) as compared with the control group (2.2 +/- 1.0 ng/mL), while it did not differ significantly between the AD and the VAD group. These findings suggest that CSF-NSE have a potential as a non-disease specific marker for the neuronal degeneration in dementia disorders.