title: Molecular properties of fibrin-based matrices for promotion of angiogenesis in vitro.
abstract: The molecular properties of fibrin-based matrices, such as fibrillar structure and covalent modifications with adhesion domains, influence the angiogenic behavior of human umbilical vein endothelial cells (HUVECs) in vitro. The fibrillar structure of fibrin-based matrices was influenced by pH but not by covalent incorporation of exogenous adhesion domains. Native fibrin-based matrices polymerized at pH 10 formed organized and longitudinally oriented fibrin fibrils, which provided a good angiogenic substrate for endothelial cells. Furthermore, upon covalent incorporation of the model ligand L1Ig6, which binds to the integrin most prominently expressed on the surface of angiogenic endothelial cells, alpha(v)beta3, these matrices became angiogenesis-promoting when polymerized at physiological pH. The amount of incorporation of L1Ig6 into the matrices depended on the fibrinogen concentration on all three fibrin chains. Soluble forms of L1Ig6 diffused rapidly out of the matrix. Most important, L1Ig6-modified matrices were very specific in inducing the angiogenic phenotype of HUVECs, whereas control cells did not differentiate on these matrices. Our results indicate that artificial extracellular matrices can influence cell behavior in two ways. One way is based on the three-dimensional fibril structure of the matrix molecules themselves, and the other is due to providing specific binding sites for direct cell-matrix interactions that lead to the activation of second-messenger cascades and thus promoting angiogenic differentiation.
authors.affiliation: Institute for Biomedical Engineering and Department of Materials, ETH and, Zurich, Switzerland. hall@biomed.mat.ethz.ch
authors.forename: H
authors.initials: H
authors.lastname: Hall
authors.forename: T
authors.initials: T
authors.lastname: Baechi
authors.forename: J A
authors.initials: JA
authors.lastname: Hubbell
mesh_terms: D001665:Binding Sites; D002448:Cell Adhesion; D002455:Cell Division; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004730:Endothelium, Vascular / Q000737:chemistry / Q000166:cytology / Q000502:physiology*; D004926:Escherichia coli / Q000235:genetics; D005109:Extracellular Matrix / Q000737:chemistry / Q000502:physiology*; D005337:Fibrin / Q000737:chemistry / Q000502:physiology*; D005782:Gels; D015870:Gene Expression; D006801:Humans; D006863:Hydrogen-Ion Concentration; D016023:Integrins / Q000378:metabolism; D039841:Leukocyte L1 Antigen Complex; D008024:Ligands; D008562:Membrane Glycoproteins / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D018919:Neovascularization, Physiologic / Q000502:physiology*; D019006:Neural Cell Adhesion Molecules / Q000737:chemistry*; D010641:Phenotype; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014471:Umbilical Veins
chemical_list: D005782:Gels; D016023:Integrins; D039841:Leukocyte L1 Antigen Complex; D008024:Ligands; D008562:Membrane Glycoproteins; D019006:Neural Cell Adhesion Molecules; D011994:Recombinant Proteins; D005337:Fibrin