title: Bladder tissue engineering: tissue regeneration and neovascularization of HA-VEGF-incorporated bladder acellular constructs in mouse and porcine animal models.
abstract: Successful tissue engineering requires appropriate recellularization and vascularization. Herein, we assessed the regenerative and angiogenic effects of porcine bladder acellular matrix (ACM) incorporated with hyaluronic acid (HA) and vascular endothelial growth factor (VEGF) in mouse and porcine models. Prepared HA-ACMs were rehydrated in different concentrations of VEGF (1, 2, 3, 10, and 50 ng/g ACM). Grafts were implanted in mice peritoneum in situ for 1 week. Angiogenesis was quantified with CD31 and Factor VIII immunostaining using Simple PCI. Selected optimal VEGF concentration that induced maximum vascularization was then used in porcine bladder augmentation model. Implants were left in for 4 and 10 weeks. Three groups of six pigs each were implanted with ACM alone, HA-ACM, and HA-VEGF-ACM. Histological, immunohistochemical (Uroplakin III, alpha-SMA, Factor VIII), and immunofluorescence (CD31) analysis were performed to assess graft regenerative capacity and angiogenesis. In mouse model, statistically significant increase in microvascular density was demonstrated in the 2 ng/g ACM group. When this concentration was used in porcine model, recellularization increased significantly from weeks 4 to 10 in HA-VEGF-ACM, with progressive decrease in fibrosis. Significantly increased vascularization, coupled with increased urothelium and smooth muscle cell (SMC) regeneration, was observed in HA-VEGF grafts at week 10 in the center and periphery, compared with week 4. HA-VEGF grafts displayed highest in vivo epithelialization, neovascularization, and SMCs regeneration. A total of 2 ng/g tissue VEGF when incorporated with HA proved effective in stimulating robust graft recellularization and vascularization, coordinated with increased urothelial bladder development and SMC augmentation into bundles by week 10.
authors.affiliation: Department of Developmental and Stem Cell Biology, The Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Yasir
authors.initials: Y
authors.lastname: Loai
authors.forename: Herman
authors.initials: H
authors.lastname: Yeger
authors.forename: Cyrielle
authors.initials: C
authors.lastname: Coz
authors.forename: Roula
authors.initials: R
authors.lastname: Antoon
authors.forename: Syed S
authors.initials: SS
authors.lastname: Islam
authors.forename: Katherine
authors.initials: K
authors.lastname: Moore
authors.forename: Walid A
authors.initials: WA
authors.lastname: Farhat
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D003094:Collagen / Q000378:metabolism; D005169:Factor VIII / Q000378:metabolism; D005355:Fibrosis; D048091:Guided Tissue Regeneration / Q000379:methods*; D006820:Hyaluronic Acid / Q000494:pharmacology*; D007150:Immunohistochemistry; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D023421:Models, Animal; D009132:Muscles / Q000187:drug effects / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D034421:Sus scrofa; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry; D001743:Urinary Bladder / Q000098:blood supply* / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D060171:Uroplakin III; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology*
chemical_list: D000199:Actins; D008562:Membrane Glycoproteins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; C554661:Upk3a protein, mouse; D060171:Uroplakin III; D042461:Vascular Endothelial Growth Factor A; D005169:Factor VIII; D006820:Hyaluronic Acid; D003094:Collagen