Figure 1.
Geometrical and flow information from the rat aortic arch acquired using Magnetic Resonance Imaging.
(A) A 3D surface description of the vessel wall of one representative rat aorta following image segmentation on the MRI image material, with maximum intensity projections in the sagittal, axial and coronal directions. The upper right panel (B) shows a phase-contrast and magnitude image at peak systole. The lower right panel (C) shows time-resolved ascending aortic volume flow-rate, measured by MRI and used as inflow boundary condition in the CFD simulation. MRI: magnetic resonance imaging; CFD: computational fluid dynamics.
Figure 2.
Distribution of WSS magnitude and vector direction in the rat aortic arch under physiological conditions.
(A) Systolic WSS magnitude and WSS vector direction in the aortic arch (dorsal view) of one representative rat. WSS is presented as colour-coded (Pa), vector direction is presented as arrows. (B) and (C) show low (dark blue) and high (red) WSS regions, respectively, visualized from another angle. Light blue arrows indicate direction of blood flow. Dashed lines in A–C indicate regions isolated for microarray analysis. WSS: wall shear stress.
Figure 3.
Increased expression of VACM and TNF in regions exposed to low WSS.
Expression of VCAM1 (A) and TNF (B) in high and low systolic WSS regions in the rat aortic arch. Gene expression was analysed by real-time PCR and normalized to TBP mRNA expression prior analysis (paired T-test) (n = 14 pairs). WSS: wall shear stress.
Figure 4.
A strong differential expression between low and high WSS regions.
Principal component analysis of Affymetrix Rat Gene 1.1 ST Array probe set data containing a total of 13 968 genes expressed in aortic tissue from 28 rat samples. Closed circles indicate low systolic WSS samples; open circles indicate high systolic WSS samples. The expression data was mean centred and scaled to unit variance prior analysis. WSS: wall shear stress.
Table 1.
Top 32 mechanosensitive genes in the rat aortic arch, classified according to function(s)/properties.
Figure 5.
Increased expression of HAND2 and TRPC4, and decreased expression of FGF12 in regions exposed to low WSS.
Immunostaining for HAND2, FGF12 and TRPC4 in low WSS/disturbed (E, G and I, respectively) and high WSS/uniform (F, H and J, respectively) flow regions, respectively. Panel A and B show staining for PECAM1, and panel C and D show staining for vWF in the corresponding regions. Sections are counterstained with Mayer’s hematoxylin. Images are representative of n = 6 animals. WSS: wall shear stress.