OBJECTIVE: Oxygen-dependent changes in vascular diameters may be detrimental when the endothelium is dysfunctional. DESIGN: Endothelial responsiveness was evaluated by brachial ultrasound and flow-mediated/nitroglycerin-mediated dilation (FMD/NMD). FMD/NMD was investigated in males with increased risk of cardiovascular disease (mean age 44+/-2 years, n=10) and matched controls without risk factors (44+/-2 years, n=10). FMD/NMD was assessed during normoxia (21% O2, 79% N2), while inhaling hypoxic gas (12.5% O2, FMDHyp/NMD), and 100% O2 supplementation (FMDO2/NMD). In a second study we addressed the effect of lipid lowering. Twenty persons with cardiovascular risk (mean age 50+/-2 years) were treated with atorvastatin (80 mg/day) and FMD/NMD was measured during normoxia, hypoxia and oxygen supplementation before, after 1 day and 3 months. RESULTS: Oxygen supplementation evoked vasoconstriction, while FMDHyp/NMD was reduced compared to FMD/NMD. Atorvastatin significantly lowered total cholesterol, LDL cholesterol, and ADMA after 1 day of treatment, while triglycerides, ApoB and hsCRP were lowered after 3 months. Atorvastatin did not change FMD/NMD irrespective of oxygen tension. CONCLUSION: Irrespective of risk factors or atorvastatin, hypoxia reduced endothelial vasodilation while oxygen supplementation evoked vasoconstriction.
OBJECTIVE:Oxygen-dependent changes in vascular diameters may be detrimental when the endothelium is dysfunctional. DESIGN: Endothelial responsiveness was evaluated by brachial ultrasound and flow-mediated/nitroglycerin-mediated dilation (FMD/NMD). FMD/NMD was investigated in males with increased risk of cardiovascular disease (mean age 44+/-2 years, n=10) and matched controls without risk factors (44+/-2 years, n=10). FMD/NMD was assessed during normoxia (21% O2, 79% N2), while inhaling hypoxic gas (12.5% O2, FMDHyp/NMD), and 100% O2 supplementation (FMDO2/NMD). In a second study we addressed the effect of lipid lowering. Twenty persons with cardiovascular risk (mean age 50+/-2 years) were treated with atorvastatin (80 mg/day) and FMD/NMD was measured during normoxia, hypoxia and oxygen supplementation before, after 1 day and 3 months. RESULTS:Oxygen supplementation evoked vasoconstriction, while FMDHyp/NMD was reduced compared to FMD/NMD. Atorvastatin significantly lowered total cholesterol, LDL cholesterol, and ADMA after 1 day of treatment, while triglycerides, ApoB and hsCRP were lowered after 3 months. Atorvastatin did not change FMD/NMD irrespective of oxygen tension. CONCLUSION: Irrespective of risk factors or atorvastatin, hypoxia reduced endothelial vasodilation while oxygen supplementation evoked vasoconstriction.
Authors: Joshua C Tremblay; Connor A Howe; Philip N Ainslie; Kyra E Pyke Journal: Am J Physiol Heart Circ Physiol Date: 2018-03-09 Impact factor: 4.733
Authors: Takuro Washio; Benjamin S Stacey; Shigehiko Ogoh; Hayato Tsukamoto; Angelo Iannetelli; Thomas S Owens; Thomas A Calverley; Lewis Fall; Christopher J Marley; Damian M Bailey Journal: J Physiol Sci Date: 2022-07-20 Impact factor: 2.257