DPP4 and Other metabolic disease: The global epidemic of COVID-19 has also determined important implications on the therapy of common metabolic disorders such as type 2 diabetes (T2D), since two coronavirus receptor proteins, dipeptidyl peptidase-4 (DPP4) and angiotensin-converting enzyme 2 (ACE2) are well established transducers of metabolic signals controlling glucose homeostasis, together with other pathways involved in the regulation of cardiovascular physiology, inflammation and renal activity [22].