title: Efficient in vivo vascularization of tissue-engineering scaffolds.
abstract: The success of tissue engineering depends on the rapid and efficient formation of a functional blood vasculature. Adult blood vessels comprise endothelial cells and perivascular mural cells that assemble into patent tubules ensheathed by a basement membrane during angiogenesis. Using individual vessel components, we characterized intra-scaffold microvessel self-assembly efficiency in a physiological in vivo tissue engineering implant context. Primary human microvascular endothelial and vascular smooth muscle cells were seeded at different ratios in poly-L-lactic acid (PLLA) scaffolds enriched with basement membrane proteins (Matrigel) and implanted subcutaneously into immunocompromised mice. Temporal intra-scaffold microvessel formation, anastomosis and perfusion were monitored by immunohistochemical, flow cytometric and in vivo multiphoton fluorescence microscopy analysis. Vascularization in the tissue-engineering context was strongly enhanced in implants seeded with a complete complement of blood vessel components: human microvascular endothelial and vascular smooth muscle cells in vivo assembled a patent microvasculature within Matrigel-enriched PLLA scaffolds that anastomosed with the host circulation during the first week of implantation. Multiphoton fluorescence angiographic analysis of the intra-scaffold microcirculation showed a uniform, branched microvascular network. 3D image reconstruction analysis of human pulmonary artery smooth muscle cell (hPASMC) distribution within vascularized implants was non-random and displayed a preferential perivascular localization. Hence, efficient microvessel self-assembly, anastomosis and establishment of a functional microvasculture in the native hypoxic in vivo tissue engineering context is promoted by providing a complete set of vascular components.
authors.affiliation: Department of Biomedicine, University of Bergen, N-5009 Bergen, Norway.
authors.forename: Anja
authors.initials: A
authors.lastname: Hegen
authors.forename: Anna
authors.initials: A
authors.lastname: Blois
authors.forename: Crina E
authors.initials: CE
authors.lastname: Tiron
authors.forename: Monica
authors.initials: M
authors.lastname: Hellesøy
authors.forename: David R
authors.initials: DR
authors.lastname: Micklem
authors.forename: Jacques E
authors.initials: JE
authors.lastname: Nör
authors.forename: Lars A
authors.initials: LA
authors.lastname: Akslen
authors.forename: James B
authors.initials: JB
authors.lastname: Lorens
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005451:Fluorescein Angiography; D006801:Humans; D007150:Immunohistochemistry; D019344:Lactic Acid / Q000494:pharmacology; D051379:Mice; D016688:Mice, Inbred NOD; D008833:Microcirculation / Q000187:drug effects; D055806:Microvessels / Q000166:cytology; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000187:drug effects; D011091:Polyesters; D011108:Polymers / Q000494:pharmacology; D011651:Pulmonary Artery / Q000166:cytology; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide)