ACE2 and diabetes mellitus: FGFs are distributed heterogeneously in human tissues, among them FGF7 plays a crucial role in pancreatic development, regeneration and the survival of implanted islets.21 Taken together, in COVID-19 patients, especially those with comorbid diabetes, the potential regulatory influence of FGFs on ACE2 expression in pancreatic islets and the role of this process in islet function and viral infection has not been explored.