LRP1 and diabetes mellitus: Mammalian target of rapamycin complex 1 (mTORC1) is highly activated in diabetes, and the decrease of low‐density lipoprotein receptor‐associated protein 1 (LRP1) in brain microvascular endothelial cells (BMECs) is a key factor leading to amyloid‐β (Aβ) deposition in the brain and diabetic cognitive impairment, but the relationship between them is still unknown.