COVID-19: is there a link between the course of infection and pharmacological agents in diabetes?

BACKGROUND: The Coronavirus disease 2019 (COVID-19) and type 2 diabetes (T2D) are two pandemics that share the dramatic impact on global mortality and economic resources. COVID-19 largely exhibits mild to moderate clinical manifestations. However, severe pneumonia with high fatality rate may occur, especially in the elderly and in patients with underlying conditions, such as diabetes and cardiovascular disease. SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) binds to the angiotensin-converting enzyme 2 (ACE2), a ubiquitous trans-membrane carboxypeptidase, to enter the cells. AIMS: This short review discusses some open questions about the link between COVID-19 and diabetes, principally focusing on the possible effects of commonly used drugs in patients with diabetes. RESULTS: Preclinical studies have reported that angiotensin receptor blockers (ARBs) and ACE inhibitors might increase ACE2 expression in several cell types. Hence, it has been speculated that the treatment with these agents might influence the course of the infection, and both harmful and beneficial effects have been supposed. Other pharmacological agents are thought to increase ACE2 expression, including statins and proliferator-activated receptor gamma (PPAR-γ) agonists. All these drug classes are broadly adopted in T2D. Besides ACE2, other unknown co-factors might be involved in cell infection. It has been recently observed that dipeptidyl peptidase-4 (DPP4), the receptor for MERS-CoV (Middle East respiratory syndrome-related coronavirus) and ACE2 have similar expression profiles in the lung. DPP4 has important metabolic and immune functions and is a target for commonly used therapies in T2D. CONCLUSIONS: Although clinical data supporting an influence of all these drugs on the course of the disease are limited, this is an interesting background for further research that might help unravel the complex mechanisms underlying the link between COVID-19 and diabetes.