082 - Cholesterol crystal formation during all stages of atherosclerosis (ID 796)
Abstract
Background and Aims
Although cholesterol crystals (CC) play a pathogenic role in atherosclerosis their presence in developing atherosclerosis has not been studied systematically. We aimed to highlight the prominent role of CC during all stages of atherosclerosis.
Methods
By incrementally increasing the period of feeding our atherogenic diet, we generated LDLR-/- mice with varying stages of atherosclerosis and analyzed the plaques by employing several different techniques including immunohistochemical staining using light and fluorescence microscopy, polarized light microscopy and both scanning and transmission electron microscopy.
Results
Our results show unexpectedly early changes in the aortic endothelium with vacuoles forming in the subendothelial space after only 1 week of atherogenic diet. Two weeks after the diet, CC formation was apparent and progressed with length of diet. While the presence of lipid, CC and vascular smooth muscles cells along with collagen progressively increased over time, the presence of macrophages decreased. Necrotic core area was dramatically expanded in advanced plaques with accumulation of plate- and needle-shaped CC, which are known to result from high levels of free cholesterol and cholesteryl esters, respectively, in the necrotic core. Lastly, by combining polarized light and fluorescence microscopic techniques, we demonstrate remarkable co-localization of CC with cholesterol microdomains through all stages of atherosclerosis, indicating that the microdomains may be a source of CC in advanced plaques.
Conclusions
Overall, we have highlighted the prominent presence of CC from a very early to advanced stages of the disease, and suggest that CC play a major role in both structural integrity and pathogenesis of atherosclerotic plaque formation.
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