To develop a blood based biomarker

Prominent expression of Tau and phosphorylated Tau in cerebrospinal fluid (CSF) is one of the well-known hallmarks of the Alzheimer’s disease (AD). High levels of p-Tau can easily differentiate AD from other neurodegenerative disease. However, the serum levels of these proteins in AD patients are not well explored. This study provides an alternative non-invasive approach to diagnose the disease by evaluating the level of Tau and p-Tau181 in serum samples. 

Blood samples were collected from 39 AD patients, 37 MCI patients and 37 elderly individuals as controls. Quantification of tau and pTau in serum samples was done with the help of a label free real time Surface Plasmon Resonance technology, and further validated by Western Blot. Statistical analysis, including Receiver Operating Characteristic (ROC), was done for further affirmation. 

The concentrations of serum Tau and p-Tau181 were significantly higher (p<0.00001) in AD (Tau; 47.49±9.00ng/μL, p-Tau181; 0.161±0.04 ng/μL) compared to MCI (Tau; 39.26±7.78 ng/μL, p-Tau181; 0.135±0.02 ng/μL) and were further compared to elderly controls (Tau; 34.92±6.58 ng/μL, p-Tau181; 0.122±0.01 ng/ μL). A significant (p<0.0001) downhill correlation was found between Tau as well as p-Tau181 levels with HMSE and MoCA score. 

This study for the first time reports the concentration of Tau and p-Tau181 in serum of AD and MCI patients. The cut-off values of Tau and p-Tau181 of AD and MCI patients with sensitivity and specificity reveal that serum level of these proteins can be used as a predictive marker for AD and MCI.