Combined NOX1/4 inhibition with GKT137831 in mice provides dose-dependent reno- and atheroprotection even in established micro- and macrovascular disease.

Aims/hypothesis: Oxidative stress is a promising target in diabetes-associated vasculopathies, with inhibitors of NADPH oxidases (NOX), in particular isoforms 1 and 4, shown to be safe in early clinical development. We have explored a highly relevant late-stage intervention protocol using the clinically most advanced compound, the NOX1/4 inhibitor GKT137831, to determine whether end-organ damage can be reversed/attenuated when GKT137831 is administered in the setting of established diabetic complications. Methods: GKT137831 was administered at two doses, 30 mg kg day and 60 mg kg day, to ApoE mice 10 weeks after diabetes induction with streptozotocin (STZ), for a period of 10 weeks. Results: Consistent with Nox4 mouse data, GKT137831 was protective in a model of diabetic nephropathy at both the 30 mg kg day and 60 mg kg day doses, through suppression of proinflammatory and profibrotic processes. Conversely, in diabetic atherosclerosis, where Nox1 and Nox4 mice have yielded qualitatively opposing results, the net effect of pharmacological NOX1/4 inhibition was protection, albeit to a lower extent and only at the lower 30 mg kg day dose. Conclusions/interpretation: As dose-dependent and tissue-specific effects of the dual NOX1/4 inhibitor GKT137831 were observed, it is critical to define in further studies the relative balance of inhibiting NOX4 vs NOX1 in the micro- and macrovasculature in diabetes. [ABSTRACT FROM AUTHOR]