Exhaled breath nitric oxide (NO) is an accepted asthma biomarker. Lung concentrations of
NO and its amino acid precursor, L-arginine, are regulated by the relative expressions of the
NO synthase (NOS) and arginase iso-forms. Increased expression of arginase I and NOS2
occurs in murine models of allergic asthma and in biopsies of asthmatic airways. Although
clinical trials involving the inhibition of NO-producing enzymes have shown mixed results,
small molecule arginase inhibitors have shown potential as a therapeutic intervention in …