Specific Lipid Peroxidation Products in Erythrocytes and Their Relationship to the Pathogenesis of Alzheimer's Disease.

Alzheimer's disease (AD) is a highly complex and multifactorial disorder in which oxidative stress acts as a key amplifying mechanism in the disease progression. Lipofuscin-like pigments (LFP), end products of lipid peroxidation, reflect oxidative damage and are capable of crossing the blood-brain barrier into the circulation. Thus, erythrocyte-derived LFP may serve as peripheral indicators of brain-specific processes. In this study, we aimed to assess the specificity of previously identified LFP for AD pathology. We analysed erythrocyte-derived LFP in individuals with biomarker-verified AD pathology (n = 40) and non-AD cognitive disorders (n = 21) across the prodromal and dementia stages, and in cognitively unimpaired individuals (n = 19). AD individuals showed significantly higher LFP levels compared with both healthy controls (p < 0.003) and the non-AD group (p ≤ 0.001). Furthermore, LFP levels correlated with established AD biomarkers in CSF, including amyloid-beta (r > -0.566) and phosphorylated tau 181 (r < 0.477). Our findings suggest that LFP may serve as potential blood-based biochemical markers reflecting oxidative stress-related processes associated with AD pathology.