Assessment of vascular wall shear stress and implications for atherosclerotic disease

Postnatal exposure to voluntary exercise but not the antioxidant catechin protects the vasculature after a switch to an atherogenic environment in middle-age mice

“…First, a concentration-response curve with the thromboxane A 2 analog 9,11-dideoxy-11α,9α-ep-oxy-methano-prostaglandin F 2α (U46619, 0.1 nM to 10 μM) was obtained for each group (n=3-5, in duplicate) to measure the half-maximum effective concentration (EC 50 ) (Table S1). In subsequent experiments (n = 3-9 per group), aorta segments were preconstricted at the EC 50 and relaxation curves to acetylcholine (Ach, 0.1 nM to 30 μM) and sodium nitroprusside (SNP, 0.1 nM to 30 μM) were performed. Two consecutive concentration-response curves separated by 30-45 min washout periods were obtained from each aortic segment.…”

“…The flow rate through the lumen (Q; in milliliters per second) required to match a given shear stress value (τ; in dynes per square centimeter) was calculated for each point on the curve according to Q=τπr 3 /4η, where η represents the viscosity (0.009 Poise) and r is the inside radius (in centimeters). The applied calculated shear stress was in the physiological range (≈0-25 dyn/cm 2 ) [42,50]. The data are presented as the percentage of maximal dilation for every shear stress value.…”

“…Results are presented as the mean ±standard error of the mean (SEM). EC 50 and the pD 2 value, the negative log of the EC 50 , were measured from individual concentration-response curves. Two-way analysis of variance (ANOVA) was used to test for interactions and main effects between initial treatments and age/diet of mice.…”

Vascular corrosion casting: analyzing wall shear stress in the portal vein and vascular abnormalities in portal hypertensive and cirrhotic rodents

“…When blood is in motion, a stress is applied parallel or tangential to the vessel wall, defined as WSS (unit: pascal). 8 It has been shown that the mechanical forces applied to vascular walls induce a number of complex cell reactions and modulate gene expression and the secretion of several biomolecules. 9 Furthermore, WSS calculations have recently been shown to provide prognostic data in the field of cardiovascular research.…”

“…However, to our knowledge, these are rarely used in the venous vascular tree and have never been applied in the setting of PHT. In normal circumstances, venous WSS ranges are considerably low, 8 but they increase in regions with vascular geometries that promote turbulent flow or increased flow velocity (eg, anastomoses and bifurcations) and therefore, by extension, they can also be applied in the field of PHT.…”