Cerebrospinal fluid neuron-specific enolase: a further marker of Alzheimer's disease?

To investigate whether neuron-specific enolase (NSE) plays a role in dementia, we measured cerebrospinal fluid (CSF) concentrations of NSE, Abeta42 and total protein tau (h-tau) in different dementia patients. We studied 159 patients: 76 with Alzheimer's disease (AD), 35 with mild cognitive impairment (MCI), 28 with frontotemporal dementia (FTD), and 20 with Lewy body disease (LBD). Thirty healthy age-matched subjects were studied as controls. NSE was measured by immunoradiometric assay, Abeta42 and h-tau were dosed by ELISA assay. Mean CSF NSE was significantly higher in AD (15.1±9.9 ng/ml) than in controls (8.3±3.5 ng/ml, p<0.01), FTD (9.1±6.1 ng/ml, p<0.05) and MCI (9.7±7.8 ng/ml, p<0.05). Aβ42 was significantly lower in AD (413.8±163.7 pg/ml) than in MCI (708.4±422.1 pg/ml, p<0.001) and controls (914.4±277.1 pg/ml, p<0.05); it was also significantly reduced in FTD (497.1±221.9 pg/ml) versus MCI (p<0.05) and controls (p<0.001); and in LBD patients (477.1±225.7 pg/ml) compared with MCI (p<0.05) and controls (p<0.001). H-tau concentration was significantly higher in AD (607.9±372.3 pg/ml, p<0.001) than in MCI (383.8±277.9 pg/ml, p<0.05), controls (176.6±43.9 pg/ml, p<0.001) and LBD (472.3±357.7 pg/ml, p<0.05); it was also increased in FTD (541.76±362.8 pg/ml) versus controls (176.6±43.9 pg/ml, p<0.001). Furthermore, NSE was inversely correlated with Aβ42 (r=-0.333, p=0<0001) and directly correlated with h-tau (r=0.370, p=0<0001). In conclusion, CSF NSE emerged as a specific indicator of AD and showed the same behaviour as the other accepted markers of AD, being correlated with both biomarkers.