Nejla YILDIRIM, Naile Merve GÜVEN AKSU, Başak Özlem PERK, Benay CAN EKE
Turkish Journal of Pharmaceutical Sciences - 2026;23(2):65-74
Objectives: The aim of this study was to compare, using ELISA, plasma levels of amyloid beta (Abeta)40, Abeta42, beta-site amyloid precursor protein cleaving enzyme 1 (BACE-1), total tau (t-tau), and phosphorylated tau (p-tau), as well as the Abeta42/Abeta40 ratio, between patients with Alzheimer's disease (AD) and healthy controls, and to evaluate their diagnostic performance in relation to demographic and lifestyle factors. Materials and Methods: This study is a single-center, cross-sectional, case-control study. Twenty-four individuals diagnosed with AD and 37 healthy volunteers included in the study. Alongside the analysis of plasma samples obtained from the participants, demographic data were analyzed to assess the potential influence of lifestyle and environmental factors on disease development. Results: Analysis of the case data showed that increasing age was a risk factor for AD, higher education level was associated with an increased risk of AD, and tea consumption was inversely associated with AD. While age is a well-known risk factor, both the increased risk of AD associated with higher education and the relatively protective effect of tea consumption against AD are supported by the literature. Evaluation of the levels of Abeta40, Abeta42, BACE-1, t-tau, and p-tau and of the Abeta42/Abeta40 ratio revealed no significant differences between the patient and control groups. Additionally, Abeta40, Abeta42, BACE-1 showed correlations in both the control and Alzheimer's groups, whereas t-tau did not. Conclusion: None of the investigated plasma biomarkers (Abeta40, Abeta42, BACE-1, t-tau, p-tau, and the Abeta42/Abeta40 ratio) discriminated Alzheimer's patients from healthy controls, with all receiver operating characteristic area under the curve values below 0.62. These findings indicate that in this cohort, plasma levels of these individual markers did not provide diagnostic value; larger longitudinal studies including cerebrospinal fluid comparisons and multi-marker panels are needed.
