MMP9 and Alzheimer disease: This study aimed to investigate plasma neuronally derived extracellular vesicle (NDEV) levels of core pathological markers [amyloid‐β (Aβ) and phosphorylated tau] and inflammatory biomarkers, including interleukin 6 (IL‐6) and matrix metalloproteinase‐9 (MMP‐9) in patients with Alzheimer’s disease (AD).