MMP9 and Alzheimer disease: The investigation of BBB breakdown using the epithelial cell transcript measures of the vascular tissue of the AD brain compared to vessel damage from CVD patients with aortic stiffness or atherosclerosis, demonstrated an overlapping downregulation of angiogenic genes, like VEGFA and IGF1 [83,207,208,209,210,211], and upregulation of inflammatory markers such as MMP9 [212].