| The vascular endothelium can be considered a disseminated organ with considerable phenotypic and functional heterogeneity. During reendothelialization and angiogenesis, endothelial cells change from their normal quiescent, growth-arrested phenotype to enter a coordinated cascade of migration, proliferation and two or three dimensional organization. This dissertation was designed to analyze several aspects of the heterogeneity of endothelial cells focusing on the functional and phenotypic properties of migrating endothelial cells.;In order to characterize endothelial cells during migration, a novel migration assay was established utilizing silicon templates (chapter 2). The migration of endothelial cells from different vascular beds was quantitated and various different treatments were tested for their ability to stimulate or inhibit endothelial cell migration (serum, extracellular matrix components, co-culture with tumor cells, suramin).;Migrating endothelial cells were phenotypically characterized and compared to growth arrested endothelial cells (chapter 3). Migrating endothelial cells were found to express a distinct pattern of cell surface hyperglycosylation and specific 25 kDa and 48 kDa Con A- and WGA-binding migration-associated cell surface glycoproteins.;Monoclonal antibodies were produced that preferentially recognize migrating endothelial cells (chapter 4). MAb 6F8 was found to preferentially bind to the leading cells of a migrating endothelial cell monolayer. MAb 6F8 identifies the 110 kDa endothelial cell migration-associated cell surface molecule (EMA-1) that is expressed by endothelial cells in large arteries and veins, in small vessels and capillaries of skin, intestine, ovary, and uterus, as well as sprouting, angiogenic endothelial cells in the ovary and uterus.;The phenotype modulating effect of organ-derived biomatrices on endothelial cell surface glycoconjugate expression was analyzed by lectin-binding studies (chapter 5). A distinct pattern of up- and downregulation of lectin binding sites on endothelial cells grown on different organ-derived biomatrices was characterized.;Functional studies were performed to study the phenotypic changes during in vitro senescence of cultured endothelial cells (chapter 6). Two different phenotypes of sprouting endothelial cells were identified. The migration and proliferation rates of endothelial cells declined during in vitro senescence which could be correlated with declining levels of endogenous bFGF expression. |
