Neutrophils linking periodontitis and Alzheimer's disease

Neutrophils, as the rapid response cells of the innate immune system, play a critical role in defending against acute infections and are intricately involved in the bidirectional regulation of neurodegenerative and chronic inflammatory disorders. Emerging evidence indicates neutrophils in the pathogenesis of Alzheimer’s disease (AD) and periodontitis through releasing inflammatory mediators, formation of neutrophil extracellular traps (NETs), and modulation of the local microenvironment. These cells could act as a crucial connection bridging the pathological processes in the brain and the oral cavity. This review explores the presence and functional roles of neutrophils in AD, provides a comprehensive overview of their mechanisms in periodontitis, and summarizes associated clinical detection indicators. Furthermore, it outlines potential neutrophil-mediated pathways that connect periodontitis and AD. By integrating findings from single-cell sequencing, animal models, and clinical data, this review offers new perspectives for early diagnosis and therapeutic intervention in periodontitis to potentially delay the progression of AD. It also highlights the dynamic role of neutrophils as a mechanistic bridge between the two diseases and discusses targeted diagnostic and treatment strategies focused on neutrophil modulation.