New activity of spironolactone. Inhibition of angiogenesis in vitro and in vivo.

Abstract

The formation of new blood vessels (angiogenesis) is a critical component in a variety of pathological settings, including solid tumor growth, macular degeneration, and atherosclerosis. We have found that orally administered spironolactone inhibited the area of angiogenesis induced by basic fibroblast growth factor (bFGF) in a rabbit corneal micropocket assay. Additionally, spironolactone inhibited bFGF- and vascular endothelial growth factor-stimulated capillary endothelial cell proliferation in vitro, inhibited bFGF-stimulated capillary endothelial cell chemotaxis in vitro, and caused avascular zones when placed on the chick chorioallantoic membrane. Experiments analyzing spironolactone metabolites revealed that the major human metabolites 6 beta-hydroxy-7 alpha-thiomethyl spironolactone and canrenoic acid retained antiangiogenic activity. The antiangiogenic activity appears to be unrelated to the antiandrogenic and antimineralocorticoid effects of spironolactone. These experiments hold promise for the potential use of spironolactone as an orally administered drug for the treatment of many diverse diseases dependent on angiogenesis.