Elevated serum amyloid-β1-42 and phosphorylated tau-181 levels in mild cognitive impairment: A cross-sectional study

BackgroundMild cognitive impairment represents a critical precursor stage for dementia, and the search for reliable blood biomarkers is essential for early detection and intervention.ObjectiveThis study aimed to explore the relationship between serum levels of amyloid-β (Aβ)_1-42 and p-tau181 proteins and mild cognitive impairment (MCI), providing a foundation for early detection of MCI.MethodsA total of 128 qualified subjects aged 60 years or above were enrolled according to the inclusion and exclusion criteria at Yangpu Hospital of Tongji University, Shanghai, China, between June 2021 and December 2022. Serum levels of Aβ_1-42 and p-tau181 were measured using enzyme-linked immunosorbent assay (ELISA). Participants were divided into MCI and non-MCI groups based on clinical diagnostic criteria. Statistical analyses were conducted using chi-square tests to evaluate demographic variables, while Mann-Whitney U tests were employed to compare protein levels between groups. Additionally, Spearman correlation analysis was utilized to examine the relationship between protein levels and MCI.ResultsThe MCI group exhibited significantly higher serum levels of Aβ_1-42 (U = 3959.0, p < 0.001) and p-tau181 (U = 3032.5, p < 0.001) compared to the non-MCI group. A strong positive correlation was found between Aβ_1-42 levels and MCI (r = 0.819, p < 0.001), while a moderate correlation was observed for p-tau181 (r = 0.426, p < 0.001). Aβ_1-42 demonstrated high diagnostic value (AUC = 0.975, 95%CI 0.954-0.997; p < 0.001) at its optimal cutoff 105.37 pg/mL, and p-tau181 exhibited moderate diagnostic efficacy (AUC = 0.747, 95%CI 0.658-0.836; p < 0.001) at its optimal cutoff 12.07 pg/mL.ConclusionsSerum levels of Aβ_1-42 and p-tau181 are associated with MCI and may serve as potential biomarkers for early detection.