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Tetrahydrobiopterin improves endothelial function in human saphenous veins
S Verma1, F Lovren, A S Dumont
1Divisions of Cardiology, Pharmacology, and Cardiac Surgery, Faculty of Medicine, The University of Calgary, Calgary, Alberta, Canada.
The Journal of Thoracic and Cardiovascular Surgery
|September 26, 2000
Summary
Tetrahydrobiopterin significantly improved endothelial function in human saphenous veins, enhancing nitric oxide production. This cofactor shows promise for improving vascular health and potentially preventing graft failure in coronary artery bypass grafting patients.
Area of Science:
- Cardiovascular Research
- Vascular Biology
- Biochemistry
Background:
- Endothelial dysfunction in saphenous veins is linked to reduced nitric oxide (NO) production.
- Tetrahydrobiopterin (BH4) is essential for NO synthesis by endothelial nitric oxide synthase (eNOS).
Purpose of the Study:
- To investigate the effect of exogenous tetrahydrobiopterin (BH4) on saphenous vein endothelial function.
- To assess BH4's impact on nitric oxide production in human vessels.
Main Methods:
- Saphenous vein segments from 17 coronary artery bypass graft patients were used.
- In vitro assessment of endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) relaxation.
- Isometric tension studies in the presence and absence of BH4 (0.1 mmol/L).
Main Results:
- Tetrahydrobiopterin significantly augmented acetylcholine-induced endothelium-mediated relaxation (16.8% vs 7.5%, P=.003).
- BH4 enhanced relaxation without altering agonist sensitivity.
- Endothelium-independent relaxation to sodium nitroprusside remained unaffected, confirming endothelium-specificity.
Conclusions:
- Acute addition of tetrahydrobiopterin beneficially impacts endothelial function in human saphenous veins.
- BH4 may play a role in mitigating endothelial dysfunction contributing to graft failure.
- Further research on chronic BH4 delivery is warranted for saphenous vein atherosclerosis.