Systemic Inflammation Predicts Alzheimer Pathology in Community Samples without Dementia

Neuroinflammation and oxidative stress (OS) are implicated in the pathophysiology of Alzheimer's disease (AD). However, it is unclear at what stage of the disease process inflammation first becomes manifest. The aim of this study was to investigate the associations between specific plasma markers of inflammation and OS, tau, and Amyloid-beta 38, 40, and 42 levels in cognitively unimpaired middle-age and older individuals. Associations between inflammatory states identified through principal component analysis and AD biomarkers were investigated in middle-age (52-56 years, n = 335, 52% female) and older-age (72-76 years, n = 351, 46% female) participants without dementia. In middle-age, a component reflecting variation in OS was most strongly associated with tau and to a lesser extent amyloid-beta levels. In older-age, a similar component to that observed in middle-age was only associated with tau, while another component reflecting heightened inflammation independent of OS, was associated with all AD biomarkers. In middle and older-age, inflammation and OS states are associated with plasma AD biomarkers.

Automated summary

Inflammation and oxidative stress are associated with the development of Alzheimer's disease. In middle-age individuals, oxidative stress is associated with tau levels. In older-age individuals, oxidative stress is only associated with tau, while another component related to heightened inflammation is associated with all AD biomarkers.