Tau protein phosphorylated at threonine 181 in CSF as a neurochemical biomarker in Alzheimer's disease: original data and review of the literature.

Cerebrospinal fluid (CSF) concentrations of total Tau and Tau phosphorylated at threonine (position 181 [pTau181]) were studied with ELISA in a group of carefully selected patients with a neurochemically supported diagnosis of Alzheimer's disease (AD, n = 9; age range, 51-89 yr) and in a group of sex- and age-matched nondemented controls (n = 9; age range, 52-81 yr). The concentration of both biomarkers is increased significantly in the AD group (total Tau, p < 0.0008; pTau181, p < 0.008). A significant correlation between CSF concentrations of both biomarkers is observed (R = 0.897; p < 0.001). Neither total Tau nor pTau181 correlates with age or degree of memory impairment, and only a tendency is observed between the concentrations of total Tau and Abeta42 in the CSF. Our results further confirm a possible role of pTau181 as a diagnostic tool in AD. The current literature regarding the physiological and pathological role of phosphorylated Tau proteins is reviewed, as well as the role of these proteins as promising biomarkers in the diagnosis of neurodegenerative disorders.