Helicobacter pylori-Derived Outer Membrane Vesicles and Cognitive Decline: Outer membrane vesicles (OMVs) derived from Helicobacter pylori (H. pylori) can cross biological barriers and enter the brain. They interact with astrocytes, microglia, and neurons via the complement component 3 (C3) - C3a receptor (C3aR) signaling pathway, inducing glial cell activation and neuronal dysfunction. This interaction contributes to the pathological progression of amyloid beta and cognitive decline. This evidence concerns the gene C3 and Mental deterioration.