Abstract 956: Cholesterol Crystals Cause Endothelial Damage and Impair Vasoreactivity
Background Cholesterol has been shown to expand when crystallizing and then be released into the circulation following plaque rupture. We hypothesized that flow of sharp ended crystals in arteries could damage the intimal surface and decrease normal vasoreactivity.
Methods Bilateral carotid arteries from seven NZW rabbits were placed in a dual perfusion chamber, preconstricted with nor-epinephrine (NE) and then challenged with acetylcholine (ACH) for endothelial reactivity and nitroprusside (SN) to evaluate for smooth muscle reactivity. Both arteries served as their own control and perfused with warm buffered saline solution (PBS). This was followed with PBS and cholesterol crystals (100–500 μm long) and then subjected to the same pharmacological challenge. Diameters were continually recorded and digitally measured at five sites in each artery and averaged. The intimal surface was then examined by scanning electron microscopy for cholesterol crystals and intimal damage.
Results The vasoconstrictor and vasodilatory response to ACH -but not SN- was significantly decreased after crystals were infused in comparison to initial control measurements (Figure 1⇓). On microscopic evaluation the intima infused with crystals demonstrated numerous sites of surface tears with evidence of cholesterol crystals perforating and embedding in the surface compared to normal controls.
Conclusion Cholesterol crystals damaged endothelium and decreased vasoreactivity. The lack of significant change in response to SN suggests that this was due to intimal injury. These data have important clinical implications regarding impaired vasoreactivity during acute cardiovascular events.