Several data in AD animal models and in AD patients indicate a possible involvement of the plasminogen activation system in AD.33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47 These data mainly show altered levels and/or activity of the most relevant components of this system: plasmin, tPA, and PAI‐1 enzymes (Table 1). This evidence concerns the gene PLG and Alzheimer disease.