Overexpressed MMP-9 has also been found in the cytoplasm of neurons, neurofibrillary tangles, senile plaques, and vascular walls of the hippocampus and cerebral cortex of AD patients, and inhibiting MMP-9 improves Aβ-mediated cognitive impairment and neurotoxicity in mice [112]. This evidence concerns the gene MMP9 and Cognitive impairment.