Serum FOXO3A: A ray of hope for early diagnosis of Alzheimer's disease.

Diagnosis of Alzheimer's disease (AD) is often difficult because of distinct and subjective clinical features, especially in the early stage. FOXO3a protein present in the cognitive centre of brain in inferior temporal region and parahippocampus. FOXO3a can be a potential novel target against AD. AD, Mild Cognitive impairment (MCI) and Geriatric Control (GC) were recruited after diagnosis by clinical assessment, MRI, TauPET and FDG-PET. We have quantified serum FOXO3a by surface plasmon resonance (SPR) and compare with TauPET between of AD, MCI patients and GC. Serum FOXO3A was significantly lower in AD (1.42 ± 0.09 ng/μl) compare to MCI (1.61 ± 0.14 ng/μl) and GC (1.89 ± 0.07 ng/μl). However, the Tau was higher in AD both in serum and also in PET scan. Serum pTau was significantly over-expressed in AD (0.176 ± 0.03 ng/μl), compare to other groups; MCI (0.16 ± 0.014 ng/μl) and GC (0.15 ± 0.024 ng/μl). Serum FOXO3A could significantly differentiate AD vs MCI, MCI vs GC and AD vs GC. However, Tau protein could only differentiate AD vs GC but not MCI vs GC. Serum FOXO3A may serve as novel blood marker for early detection for AD and target for therapeutic intervention.