Oxidative stress is associated with impaired arterial elasticity

Arterial stiffening may lead to hypertension, greater left ventricular after-load and adverse clinical outcomes. The underlying mechanisms influencing arterial elasticity may involve oxidative injury to the vessel wall. We sought to examine the relationship between novel markers of oxidative stress and arterial elastic properties in healthy humans.

We studied 169 subjects (mean age 42.6 ± 14 years, 51.6% male) free of traditional cardiovascular risk factors. Indices of arterial stiffness and wave reflections measured included carotid-femoral Pulse Wave Velocity (PWV), Augmentation Index (Aix) and Pulse Pressure Amplification (PPA). Non-free radical oxidative stress was assessed as plasma oxidized and reduced amino-thiol levels (cysteine/cystine, glutathione/GSSG) and their ratios (redox potentials), and free radical oxidative stress as derivatives of reactive oxygen metabolites (dROMs). Inflammation was assessed as hsCRP and interleukin-6 levels. The non-free radical marker of oxidative stress, cystine was significantly correlated with all arterial indices; PWV (r=0.38, p<0.001), Aix (r=0.35, p<0.001) and PPA (r=-0.30, p<0.001). Its redox potential, was also associated with PWV (r=0.22, p=0.01), while the free radical marker of oxidative stress dROMS was associated with Aix (r=0.25, p<0.01). After multivariate adjustment for age, gender, arterial pressure, height, weight, heart rate and CRP, of these oxidative stress markers, only cystine remained independently associated with PWV (p=0.03), Aix (p=0.01) and PPA (p=0.05).

In healthy subjects without confounding risk factors or significant systemic inflammation, a high cystine level, reflecting extracellular oxidant burden, is associated with increased arterial stiffness and wave reflections. This has implications for understanding the role of oxidant burden in pre-clinical vascular dysfunction.