Abstract 510: Morphometrics of Calcification in Carotid Endarterectomy Tissue
Arterial calcification plays a significant role in the pathogenesis of carotid atherosclerotic plaques development. The aim of this study was to provide a detailed analysis of calcification morphology based on histological features in carotid endarterectomy (CEA) specimens. In particular, the emphasis is on calcium nodule size/shape and its relation to tissue and lumen morphologies. These studies will help elucidate the mechanisms of the arterial calcification process.
Representative frozen sections were cut from the common, bifurcation, internal and external segments obtained from 9 CEA samples. Histological stains were used to show the calcified particles, tissue compositions and lipids deposition. The digitized images of sections were warped when necessary to achieve closure of the vessel wall. Image analysis was applied to 2 samples to determine the morphologies of calcium particles (size, shape and perimeter), lumen (area and perimeter) and tissue (area and compositions) using ImageJ. Total non-collagen protein and collagen protein were semi-quantitatively analyzed in one sample.
Calcification occurred predominantly in the bifurcation and internal segments of the CEA, occupying up to 17% of the cross-sectional tissue area. Occassionally, calcification was found in the external branch. The lipids distribution is quite patchy. All calcified particles were contained in the intimal layer of the carotid wall. The lumen area was increased in the bifurcation segment, but it deviated from a patent circular shape. The amount of calcific particles was positively correlated with the tissue area (R2=0.8365, p=0.0015). As the calcium particle increase in size, the shape became more elongated. Collagen accounted for up to 5% of the total non-collagen protein.
Different stages of calcification progression occur at the same time, while the very small sized calcium particle grow in size in all directions, the medium sized particle coalescing with its neighbors to form larger particles. The calcification is accompanied by increase in tissue size and distortion of lumen. Presumably, the kinetics of calcification is determined by the composition of the extracellular matrix and the interstitial cells may play a role in the process.
- © 2013 by American Heart Association, Inc.