Endothelial fibronectin induces disintegration of endothelial integrity and leads to atherosclerotic vascular pathologies [1, 18, 95], supporting our findings that reduced fibronectin 1 protects the blood–brain barrier integrity disrupted by APOEε4. Our findings are coherent with the previous observations, where AD-related changes in collagen and fibronectin around the blood–brain barrier (BBB) and alterations in the BBB's structure and function were documented [43, 80, 92]. Here, FN1 is linked to Alzheimer disease.