An eye’s look unmasks the mystery: correlation between serum amyloid beta peptide, hippocampal volume and retinal thickness in Alzheimer`s disease

Abstract Background Alzheimer’s disease (AD) is the commonest worldwide neurodegenerative disorder. Nevertheless, it usually face difficulties to guarantee a secured initial diagnosis. For this reason, neurologists are in dire need for developing potential biomarkers that could be relied upon confidentially in early diagnosis of AD. Hopefully, this will open the gate for novel modifying therapy to fight with all their might. In this current study, we aimed to correlate plasma levels of tau and Aβ with the changes that occur in hippocampal volume and thickness of retinal fiber layers in patients who clinically diagnosed with AD spectrum. A cross-sectional study enrolled 60 AD patients who fulfilled inclusion and exclusion criteria were subjected to cognitive, radiologic, laboratory and optical coherence tomography (OCT) assessments. Results Tau, Aβ1–40, and Aβ1–40/Aβ1–42 ratio are significant discriminators of AD at cutoff values of >23.45, > 84.4, and > 1.95, respectively. MRI hippocampal volume in both right and left sides are also good discriminators of AD at cutoff values of ≤ 2.997, and ≤ 2.994, respectively. A significant correlations were reported between tau with Aβ1–40, Aβ1–42, MMSE and MRI right and left hippocampal volumes. On comparing moderate versus mild AD, there was a high significant levels of tau, Aβ1–42, Aβ1–40/Aβ1–42 ratio. Conclusions We clarify that several biomarkers could be potentially used for confirming the diagnosis of AD. Assessment of plasma amyloid level, detection of hippocampal atrophy and retinal nerve fiber layer thickness changes are promising tools for early diagnosis of AD.