ER stress is linked with cardiovascular diseases; and in ECs, many risk factors including hyperglycemia, oxidized phospholipids, homocysteine, and hexosamine all contribute to ER stress, which has been proven by the activation of three ER-resident transmembrane proteins, such as activating transcription factor 6 (ATF6), protein kinase RNA-like ER kinase (PERK), and inositol-requiring enzyme 1 (IRE1) [21,22]. Here, ERN1 is linked to Hyperglycemia.