Péptidos β-amiloides y proteína tau fosforilada, como biomarcadores sanguíneos útiles de diagnóstico temprano en Alzheimer. Una revisión Sistemática

Abstract

Alzheimer’s disease is the leading cause of dementia worldwide, and its early diagnosis remains a major clinical challenge due to the invasive nature, high cost, and limited accessibility of conventional diagnostic methods such as cerebrospinal fluid analysis and advanced neuroimaging techniques. In this context, blood-based biomarkers have emerged as a promising alternative for the early detection of underlying neuropathological processes. This systematic review aimed to analyze the diagnostic utility of blood-based β-amyloid peptides and phosphorylated tau protein, compared with cerebrospinal fluid biomarkers, for the early diagnosis of Alzheimer’s disease. The review was conducted in accordance with the PRISMA 2020 guidelines and included experimental studies published between 2015 and 2025 retrieved from PubMed/MEDLINE, Scopus, ScienceDirect, SpringLink and Dialnet Plasma biomarkers such as the Aβ42/Aβ40 ratio, p-tau181, p-tau217, and p-tau231 were evaluated, along with the analytical methods employed and their diagnostic performance. The findings indicate that plasma phosphorylated tau biomarkers, particularly p-tau217, exhibit high diagnostic sensitivity and specificity, with performance comparable to cerebrospinal fluid biomarkers. In contrast, plasma β-amyloid biomarkers demonstrated moderate diagnostic accuracy, which improved when incorporated into combined diagnostic models. In conclusion, blood-based phosphorylated tau biomarkers represent a promising, minimally invasive, and clinically feasible tool to enhance the early diagnosis of Alzheimer’s disease, although further standardization and multicenter validation are required prior to widespread clinical implementation.