Improvement of vascular function by acute and chronic treatment with the PDE-5 inhibitor sildenafil in experimental diabetes mellitus
Article first published online: 29 JAN 2009
2008 British Pharmacological Society
British Journal of Pharmacology
Volume 153, Issue 5, pages 886–893, March 2008
How to Cite
Schäfer, A., Fraccarollo, D., Pförtsch, S., Flierl, U., Vogt, C., Pfrang, J., Kobsar, A., Renné, T., Eigenthaler, M., Ertl, G. and Bauersachs, J. (2008), Improvement of vascular function by acute and chronic treatment with the PDE-5 inhibitor sildenafil in experimental diabetes mellitus. British Journal of Pharmacology, 153: 886–893. doi: 10.1038/sj.bjp.0707459
- Issue published online: 29 JAN 2009
- Article first published online: 29 JAN 2009
- (Received June 5, 2007, Revised July 18, 2007, Accepted August 20, 2007)
- endothelial function;
- nitric oxide;
- oxygen radicals;
Background and purpose:
Diabetes-associated vascular dysfunction contributes to increased cardiovascular risk. We investigated whether the phosphodiesterase-5 inhibitor sildenafil would improve vascular function in diabetic rats.
Male Wistar rats were injected with streptozotocin (50 mg kg-1, i.v.) to induce insulin-deficient diabetes. Direct effects of sildenafil as well as modification of endothelium-dependent and -independent vasorelaxation were investigated in vitro. The effects of acute and chronic (2 week) treatment in vivo of sildenafil on vascular function were also characterized in isolated aortic segments in organ bath chambers 4 weeks after diabetes induction.
Sildenafil induced a concentration-dependent vasorelaxation, which was attenuated by the nitric oxide (NO) synthase inhibitor, NG-nitro-L-arginine. Acetylcholine-induced endothelium-dependent as well as endothelium-independent relaxation induced by the NO donor, DEA-NONOate, was significantly reduced in aortae from diabetic rats. Incubation with sildenafil in vitro normalized both endothelium-dependent and -independent relaxation in aortae from diabetic rats. Acute as well as chronic in vivo treatment with sildenafil resulted in enhanced endothelium-dependent and -independent vasorelaxation. Superoxide formation was increased in diabetes, associated with enhanced membrane expression of the NAD(P)H oxidase subunit gp91phox and Rac, which were both reduced by chronic treatment with sildenafil.
Conclusions and implications:
We demonstrate that sildenafil treatment rapidly and chronically improves vascular relaxation in diabetic rats. Treatment with sildenafil might provide a similarly beneficial effect in diabetic patients.
British Journal of Pharmacology (2008) 153, 886–893; doi:10.1038/sj.bjp.0707459; published online 24 September 2007