Reduced in vitro repair in endothelial cells harvested from the intercostal ostia of porcine thoracic aorta

The ability of large-vessel endothelium to repair itself rapidly after injury is important in the maintenance of its barrier function and in limiting the development and progression of atherosclerosis. Because dysfunctional repair may be involved in the pathogenesis of some atherosclerotic plaques, including those at the ostia of aortic branches, linear mechanical denuding wounds were made in confluent monolayers of endothelial cells harvested by scraping from the flow divider, the upstream wall of the intercostal branch and unbranched regions in the thoracic aorta. The extent of wound closure was significantly lower in cells derived from either side of the intercostal branches, compared with cells from unbranched areas. The wound edge of cells harvested from the flow divider and its opposite wall closed by 22 +/- 0.084 mu m and 22 +/- 1.3 mu m, respectively, versus control, unbranched endothelial cells (30 +/- 2.2 mu m) at 24 hours and by 48 hours, 48 +/- 3.4 mu m and 47 +/- 3.6 mu m compared with control (61 +/0 3.4 mu m). Extent of wound closure in cells harvested by scraping from unbranched regions was comparable with collagenase-harvested endothelial cells at 24 and 48 hours. Distribution of F-actin microfilaments, tubulin and centrosomes have been shown to be disrupted at the wound edge in poorly migrating cells. In our study, however, no differences were observed in cytoskeletal distribution between cells from branched, unbranched and control areas. Thus, aortic endothelial cells from the intercostal branch region show a reduced ability to repair wounds compared with cells harvested from unbranched aorta. The mechanism for this difference is currently unknown.