Neuroinflammation: A Driving Force in the Onset and Progression of Alzheimer's Disease.

Background/Objectives: The goal of this commentary is to highlight several key components of the inflammatory process as it relates to amyloid toxicity in Alzheimer's disease (AD), including the role of neuroinflammatory factors and peripheral inflammatory events. Methods: Google Scholar and PubMed were used to find articles with the following keywords: Alzheimer's disease, amyloids, neuroinflammation, peripheral inflammation, microglia, cytokines, and treatments. Sources that were case reports, not peer-reviewed, or older than 30 years were excluded. Abstracts were reviewed first for their relevance before the full text was considered. Methods sections were reviewed to ensure the interventional papers included were randomized controlled trials, meta-analyses, or systematic reviews; however, several literature reviews were also included due to the relevance of their background information. Results: Based on the literature review, we chose to concentrate on microglia, cytokine signaling, and peripheral inflammation markers. We found that microglia activation and subsequent microglia-driven inflammation play a pivotal role in the pathomechanism of AD. Additionally, cytokines such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-a) appear to contribute to amyloid accumulation and cell damage. Finally, the increased permeability of the blood-brain barrier (BBB) allows for the peripheral inflammatory process to contribute to the inflammation of the central nervous system (CNS) and amyloid-beta (Aβ) accumulation. Conclusions: Current evidence suggests that the immune system plays a pivotal role in the pathogenesis of AD, both in the CNS and the periphery.