Some of these proteins have been previously reported as AD biomarkers, such as gelsolin (31), serotransferrin (32, 33), metalloproteinase inhibitor 1 (34), mitogen-activated protein kinase 1 (35), pigment epithelium-derived factor (36) and brain-derived neurotrophic factor (37, 38). Here, TIMP1 is linked to Alzheimer disease.