Experimental aortic valve stenosis in rabbits
Marie-Claude Drolet, MSc*,
Marie Arsenault, MD* and
Jacques Couet, PhD*,*
* Groupe de Recherche en Valvulopathies, Institut de Cardiologie de Québec, Centre de Recherche Hôpital Laval, Université Laval, Quebec, Canada
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Figure 1 Total cholesterol (A) and Ca2+ (B) circulatory levels in hypercholesterolemic rabbits receiving (open circles) or not receiving (solid circles) daily supplements of vitamin D2. results are expressed as the mean value ± SEM in mmol/l (n = 8). the hatched region in part B corresponds to the mean (line) ± 2 SD of serum calcium concentrations in normal rabbits (n = 18).
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Figure 2 Effects of hypercholesterolemia in rabbits receiving (Chol+vit D2) or not receiving (Chol) daily supplements of vitamin D2 on aortic valve function, as assessed by echocardiography. The aortic valve area (AVA) (left column), indexed AVA (arbitrary units [AU]) (middle column), and maximal gradient (mm Hg) (right column) were calculated as described in the Methods section and are represented for each individual rabbit. ns = not significant.
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Figure 3 Two-dimensional imaging of the aortic valve by echocardiography. The valves were imaged in the parasternal long-axis (left panels) and short-axis (right panels) views. In control animals (control), the aortic valve is a thin, barely visible structure. In cholesterol-fed animals with vitamin D (Chol+Vit D2), the aortic leaflets become thickened and hyperechogenic. The valve area is reduced, as shown by the decreased opening of the valve in systole. Valve opening was traced over this echocardiographic image only as a visual aid to the reader and was not used to calculate aortic valve area.
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Figure 4 Aortic valve photographs from rabbits fed with normal chow (left) or cholesterol plus vitamin D2 (right). The whole aortic valve is shown attached to the aortic annulus, with a small portion of the ascending aorta. The reduced opening (center) can be readily assessed.
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Figure 5 Transvalvular aortic gradients in control (top panel) and cholesterol plus vitamin D2 animals (bottom panel) by continuous-wave Doppler imaging.
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Figure 6 Calcium deposits as assessed by alizarin red S (left column) and von Kossa’s (right column) staining in the attachment site (B, F), aortic valve leaflet (C, G), and aortic annulus (D, H) in rabbits treated with cholesterol enriched diet plus vitamin D2. (A and E) Sections from a normal aortic valve.
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