Plasma nitrite response and arterial reactivity differentiate vascular health and performance
Section snippets
Patient characteristics
All subjects were recruited from the Duke University Medical Center Cardiology-Vascular clinics and surrounding area as part of ongoing enrollment for the Angiogenesis and Mechanisms of Exercise Training in PAD (AMNESTI) clinical trial. Prior to participation all subjects signed an informed consent document approved by Duke University Medical Center Internal Review Board. All subjects were aged 40–75 years. Subjects were placed in the groups.
RF = greater than 2 traditional risk factors, no
Patient characteristics
There were 41 subjects in the risk factor (RF) group, 10 in the diabetes only group (DM), 29 in the PAD only group, and 9 in the DM + PAD group. The subject characteristics are summarized in Table 1. The RF group was younger, had higher fitness level, and lower resting systolic blood pressures than the other groups. As expected both the RF and DM had higher ABI measures than the two diagnosed PAD groups. There were no differences in resting diastolic blood pressures or brachial artery diameters
Discussion
The major finding of this study is that subjects with clinically diagnosed vascular disease (PAD) have significantly blunted responses in: (a) localized NO-dependant endothelial function (BAFMD), (b) the ability to increase plasma nitrite (ΔNO2−), and (c) exercise tolerance (VO2peak) in comparison to those with sub-clinical disease. Additionally, these physiological (BAFMD), biochemical (ΔNO2−), and physical (VO2peak) indicators of vascular health/function are interrelated. In fact, within a
Summary/conclusions
The results of this study present a unique view into the biochemistry and physiological responsiveness of the vasculature in sub-clinical and clinical disease patients. Measures of endothelial function and physical performance were all able to differentiate between subjects at risk for CVD and those with clinical disease. The ability to up regulate plasma NO2− to exercise stress was also able to differentiate between the two sub-clinical “at risk” groups. Additionally, we present evidence that
Acknowledgments
Assistance for treadmill testing and exercise training in this study was provided by staff at the Duke University Medical Center, Center for Living Campus, Durham, NC 27710.
These findings were partially supported in by the NIH Grant 5R01 HL-075752-05.
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