Integrating neuroinflammation biomarkers into the ATN(X) framework: Advances in Alzheimer's pathogenesis, diagnosis, and insights from non-human primate models.

The amyloid/tau/neurodegeneration (ATN) biomarker framework has greatly progressed the diagnosis and staging of Alzheimer's disease (AD). However, recent research highlights neuroinflammation as an equally critical factor in AD pathology across humans, rodents, and non-human primates (NHPs). This review evaluates the combined use of ATN and neuroinflammatory biomarkers-such as glial fibrillary acidic protein (GFAP) (astrocytic marker) and triggering receptor expressed on myeloid cells 2 (TREM2)/ ionized calcium-binding adapter molecule 1 (IBA-1) (microglial markers)-in elucidating AD mechanisms, promoting early diagnosis, and shaping therapeutic strategies. It also summarizes the key features and translational potential of NHP models that closely mimic human AD pathology, highlighting the promising prospects of integrating these models with the ATN(X) biomarker system. These insights strengthen the link between biomarkers, NHP research, and clinical practice, opening new avenues for the early detection and treatment strategies of AD. HIGHLIGHTS: Neuroinflammation biomarkers, including glial fibrillary acidic protein (GFAP), triggering receptor expressed on myeloid cells 2 (TREM2)/sTREM2, and YKL-40, show strong clinical potential in Alzheimer's disease (AD). Incorporating neuroinflammation biomarkers into the ATN(X) framework may enhance diagnostic precision. Advanced non-human primate (NHP) models closely replicate human brain pathology, addressing key limitations of mouse models. Measuring ATN(X) biomarkers in NHPs may improve clinical translation and support early diagnosis of AD. Optimizing NHP models-including ApoE4 status, injection protocols, and gene-editing approaches-is crucial for reproducibility and efficiency.