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Tetrahydrobiopterin restores endothelial function in long-term smokers
S Ueda1, H Matsuoka, H Miyazaki
1Department of Internal Medicine III, and the Cardiovascular Research Institute, Kurume University School of Medicine, Fukuoka, Japan.
Journal of the American College of Cardiology
|January 15, 2000
Summary
Tetrahydrobiopterin (BH4) supplementation improved nitric oxide (NO) bioactivity in smokers, enhancing endothelium-dependent vasodilation. This suggests BH4 deficiency contributes to impaired NO function in smokers.
Area of Science:
- Cardiovascular Research
- Endothelial Function
- Pharmacology
Background:
- Smokers exhibit impaired endothelium-derived nitric oxide (NO) bioactivity.
- Tetrahydrobiopterin (BH4) is a crucial cofactor for NO synthase, and its deficiency reduces NO bioactivity.
Purpose of the Study:
- To investigate whether tetrahydrobiopterin (BH4) supplementation can enhance nitric oxide (NO) bioactivity in smokers.
Main Methods:
- Healthy male smokers and nonsmokers received sapropterin hydrochloride (an active BH4 analogue).
- Plasma BH4 levels and brachial artery flow-mediated vasodilation (FMV) were measured before and after administration.
- NO synthase inhibition was used to confirm the NO-dependent mechanism.
Main Results:
- Sapropterin administration increased plasma BH4 levels significantly in all participants.
- Smokers showed impaired baseline FMV, which was significantly improved by sapropterin.
- The vasodilatory effect of sapropterin in smokers was abolished by NO synthase inhibition.
Conclusions:
- BH4 supplementation effectively improved NO bioactivity in smokers.
- Reduced BH4 bioactivity may underlie the impaired NO-dependent vasodilation observed in smokers.