Abstract
BACKGROUND: Altered vascular shear profiles may contribute to the development of atherosclerosis. Physical activity promotes anti-atherogenic shear patterns, resulting in reduced cardiovascular disease risk. Adults with metabolic syndrome (MetSyn) are at increased risk of developing atherosclerosis and cardiovascular disease. Thus, we hypothesized that conduit artery antegrade shear rate (ASR) would increase and retrograde shear rate (RSR) and oscillatory shear indices (OSI) would decrease in MetSyn patients (n = 16, 51 ± 2 years) after participation in a diet and exercise programme (DEP). METHODS: Blood flow (Doppler ultrasound, brachial and femoral arteries) was measured, and shear rates were calculated in MetSyn patients before and after 12 weeks of DEP participation. In addition, plasma samples were collected to measure atherogenic markers. RESULTS: Diet and exercise programme participation increased resting leg blood flow and femoral artery ASR (P ≤ 0·05), and tended to decrease OSI (P = 0·09); RSR did not change (P>0·05). No changes in resting arm blood flow or ASR were observed (P>0·05), and both RSR and OSI increased after participation (P≤0·05). DEP participation reduced plasma vascular cell adhesion molecule(VCAM)-1 (P = 0·03), with a trend for reduced intercellular cell adhesion molecule(ICAM)-1 (P = 0·09) (i.e. atherogenic markers). CONCLUSION: Modest changes in diet and physical activity result in limb-specific improvements in vascular shear profiles and reduced systemic markers of atherosclerotic risk in MetSyn patients. These data provide novel physiologic insight into adaptations that may limit the progression of atherosclerosis in patients with MetSyn.