INS and obesity due to melanocortin 4 receptor deficiency: The Trx/TrxR system exerts crucial functions in adipocyte dysfunction and obesity, carbohydrate metabolism—including insulin production and sensitivity—β-cell death, blood pressure regulation, inflammation, chemotactic activity of macrophages, and atherogenesis, enough to be proposed as a new additive biomarker for the MetS, IR, and T2D, as well as for the treatment of hypertension and atherosclerosis [147].