ABSTRACT
COVID-19 has spread globally, affecting almost 160 million individuals. Elderly and pre-existing patients (such as diabetes, heart disease and asthma) seem more susceptible to severe illness with COVID-19. Roflumilast was licensed for usage in the European Union in July 2010 as a phosphodiesterase-4 (PDE4) inhibitor. Under preclinical studies, roflumilast has been shown to decrease bleomycin-induced lung fibrosis, lung hydroxyproline and right heart thickening. The current study reviewed existing data that the PDE-4 inhibitor, a roflumilast, protects renal tissues and other major organ systems after COVID-19 infection by decreasing immune cell infiltration. These immune-balancing effects of roflumilast were related to a decrease in oxidative and inflammatory burden, caspase-3 suppression and increased protein kinase A (PKA)/cyclic A.M.P. (cAMP) levels in renal and other organ tissue.