engleski

Effects of tetrahydrobiopterin on venous bubble grade and acute diving-induced changes in cardiovascular function

Introduction: Self-contained underwater breathing apparatus diving reduces cardiovascular function and increases pulmonary artery pressure (PAP) up to 3 days after a single dive. Acute antioxidants partially attenuated arterial endothelial dysfunction, whereas cardiac and PA functions were unaffected. We tested the hypothesis that acute tetrahydobiopterin (BH4), as a cofactor of endothelial nitric oxide (NO) synthase, reduces bubble grade (BG) and attenuates alteration in cardiovascular function after diving because of increased NO bioavailability. Materials and methods: Mean PAP (mPAP), PA acceleration time and right ventricle ejection time, left ventricle ejection fraction (LV-EF) and BG were measured after oral placebo (P), vitamin C (C) or a combination of vitamin C and BH4 (BH4) in a randomized, placebo controlled trial before and after field dive to 30 m of sea water for 30 min bottom time. Results: Eight recreational divers performed three dives with a 3-days period between them. Regarding the primary hypothesis, no difference was observed between postdive changes in BG (2Æ 1 ± 2Æ 2 bubbles cm)2 for P, 3Æ 4 ± 3Æ 9 for C and 3Æ 6 ± 2Æ 1 for BH4), mPAP (25Æ 6 ± 6Æ 5 mmHg for P, 25Æ 9 ± 8Æ 6 for C and 22Æ 6 ± 3Æ 5 for BH4) and LV-EF (62Æ 6 ± 4Æ 6% for P, 61Æ 4 ± 3Æ 9 for C and 61Æ 6 ± 3Æ 7 for BH4) with all three conditions. Conclusion: This suggests that co-administration of BH4 and vitamin C does not improve heart and pulmonary artery function after diving.

antioxidants; BH4; cardiovascular function; ultrasound; venous gas bubbles

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