Systemic sclerosis (SSc) is a rare, auto-immune disease characterized by debilitating fibrosis and vascular dysfunction, however, little is known about the circulatory response to exercise in this population. Therefore, we examined the peripheral hemodynamic and vasodilatory responses to handgrip exercise in 10 patients with SSc (61 ± 4 yr) and 15 age-matched healthy controls (56 ± 5 yr). Brachial artery diameter, blood flow, and mean arterial pressure (MAP), were determined at rest and during progressive static-intermittent handgrip exercise. Patients with SSc and controls were similar in body stature, handgrip strength, and mean arterial pressure (MAP), however, brachial artery blood flow at rest was nearly two-fold lower in patients with SSc compared to controls (22 ± 4 vs. 42 ± 5 ml/min, respectively; P<0.05). Additionally, SSc patients had an ~18% smaller brachial artery lumen diameter with a ~28% thicker arterial wall at rest (P<0.05). Although, during handgrip exercise, there were no differences in MAP between the groups, exercise-induced hyperemia and therefore vascular conductance were ~35% lower at all exercise workloads in patients with SSc (P<0.05). Brachial artery vasodilation, as assessed by the relationship between ∆ brachial artery diameter and ∆ shear rate, was significantly attenuated in the patients with SSc (P<0.05). Finally, vascular dysfunction in the patients with SSc was accompanied by elevated blood markers of oxidative stress and attenuated endogenous antioxidant activity (P<0.05). Together, these findings reveal attenuated exercise-induced brachial artery blood flow and conduit arterial vasodilatory dysfunction during handgrip exercise in SSc and suggests that elevated oxidative stress may play a role.
- vascular function
- oxidative stress
- Copyright © 2016, American Journal of Physiology-Heart and Circulatory Physiology