title: Spontaneous fibroblast-derived pericyte recruitment in a human tissue-engineered angiogenesis model in vitro.
abstract: Cooperation between endothelial cells and pericytes is essential to the stabilization and maturation of blood microvessels. We developed a unique in vitro tissue-engineered model to study angiogenesis. The human endothelialized reconstructed connective tissue model promotes the formation of a three-dimensional branching network of capillary-like tubes (CLT) with closed lumens. The purpose of this work was to investigate whether pericytes were spontaneously recruited around CLT in the model. We demonstrated that smooth muscle α-actin (SMA)-positive cells were found closely associated with PECAM-1-positive capillaries in the model. Twelve percent (±2.6) of SMA-positive cells were detected along with 15% (±1.64) von Willebrand factor-positive endothelial cells in the culture system after 31 days of in vitro maturation. Conversely, no SMA-positive cells were detected in reconstructed connective tissues made solely of fibroblasts. Knowing that PDGF is a major factor in the recruitment of pericytes, we showed that blockade of the PDGFB receptor using the inhibitor AG1296 induced an overall 5, 2.6, and 2.4-fold decrease in the SMA-positive cells, von Willebrand factor-positive cells, and number of capillaries, respectively. Using combinations of human GFP-positive fibroblasts and endothelial cells, we demonstrated that pericytes were recruited from the fibroblast population in the model. In conclusion, our tissue-engineered culture system promotes the spontaneous formation of a network of capillaries and the recruitment of pericytes derived from fibroblasts. Since pericytes are essential components of the blood microvasculature, this culture system is a powerful model to study angiogenesis and endothelial cell/pericyte interactions in vitro.
authors.affiliation: Centre LOEX de l'Université Laval, Centre de Recherche FRSQ du Centre Hospitalier Affilié Universitaire de Québec, Département de Chirurgie, Faculté de Médecine, Université Laval, Québec, Canada. francois.berthod@chg.ulaval.ca
authors.forename: François
authors.initials: F
authors.lastname: Berthod
authors.forename: Julie
authors.initials: J
authors.lastname: Symes
authors.forename: Nathalie
authors.initials: N
authors.lastname: Tremblay
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Medin
authors.forename: François A
authors.initials: FA
authors.lastname: Auger
mesh_terms: D000199:Actins / Q000378:metabolism; D000077214:Becaplermin; D002196:Capillaries / Q000166:cytology / Q000502:physiology; D018929:Cell Culture Techniques; D005347:Fibroblasts / Q000166:cytology* / Q000502:physiology*; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D007231:Infant, Newborn; D008955:Models, Cardiovascular; D018919:Neovascularization, Physiologic / Q000502:physiology*; D020286:Pericytes / Q000166:cytology* / Q000502:physiology*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D020574:Proto-Oncogene Proteins c-sis / Q000378:metabolism; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000378:metabolism; D023822:Tissue Engineering / Q000379:methods*; D014841:von Willebrand Factor / Q000378:metabolism
chemical_list: D000199:Actins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D020574:Proto-Oncogene Proteins c-sis; D014841:von Willebrand Factor; D000077214:Becaplermin; D020797:Receptor, Platelet-Derived Growth Factor beta