title: Engineering vascularized soft tissue flaps in an animal model using human adipose-derived stem cells and VEGF+PLGA/PEG microspheres on a collagen-chitosan scaffold with a flow-through vascular pedicle.
abstract: Insufficient neovascularization is associated with high levels of resorption and necrosis in autologous and engineered fat grafts. We tested the hypothesis that incorporating angiogenic growth factor into a scaffold-stem cell construct and implanting this construct around a vascular pedicle improves neovascularization and adipogenesis for engineering soft tissue flaps. Poly(lactic-co-glycolic-acid/polyethylene glycol (PLGA/PEG) microspheres containing vascular endothelial growth factor (VEGF) were impregnated into collagen-chitosan scaffolds seeded with human adipose-derived stem cells (hASCs). This setup was analyzed in vitro and then implanted into isolated chambers around a discrete vascular pedicle in nude rats. Engineered tissue samples within the chambers were harvested and analyzed for differences in vascularization and adipose tissue growth. In vitro testing showed that the collagen-chitosan scaffold provided a supportive environment for hASC integration and proliferation. PLGA/PEG microspheres with slow-release VEGF had no negative effect on cell survival in collagen-chitosan scaffolds. In vivo, the system resulted in a statistically significant increase in neovascularization that in turn led to a significant increase in adipose tissue persistence after 8 weeks versus control constructs. These data indicate that our model-hASCs integrated with a collagen-chitosan scaffold incorporated with VEGF-containing PLGA/PEG microspheres supported by a predominant vascular vessel inside a chamber-provides a promising, clinically translatable platform for engineering vascularized soft tissue flap. The engineered adipose tissue with a vascular pedicle could conceivably be transferred as a vascularized soft tissue pedicle flap or free flap to a recipient site for the repair of soft-tissue defects.
authors.affiliation: Department of Plastic Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. Electronic address: lukeqixu@yahoo.com.
authors.forename: Qixu
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Plastic Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Justin
authors.initials: J
authors.lastname: Hubenak
authors.affiliation: Department of Plastic Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Tejaswi
authors.initials: T
authors.lastname: Iyyanki
authors.affiliation: Department of Plastic Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Erik
authors.initials: E
authors.lastname: Alred
authors.affiliation: Department of Plastic Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Kristin C
authors.initials: KC
authors.lastname: Turza
authors.affiliation: Department of Plastic Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Greg
authors.initials: G
authors.lastname: Davis
authors.affiliation: Department of Plastic Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Edward I
authors.initials: EI
authors.lastname: Chang
authors.affiliation: Department of Plastic Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Cynthia D
authors.initials: CD
authors.lastname: Branch-Brooks
authors.affiliation: Department of Plastic Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Elisabeth K
authors.initials: EK
authors.lastname: Beahm
authors.affiliation: Department of Plastic Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Butler
mesh_terms: D017667:Adipocytes / Q000166:cytology*; D000818:Animals; D001011:Aorta / Q000473:pathology; D049109:Cell Proliferation; D002470:Cell Survival; D048271:Chitosan / Q000737:chemistry; D003094:Collagen / Q000737:chemistry; D017077:Culture Media, Conditioned / Q000737:chemistry; D005260:Female; D049452:Green Fluorescent Proteins / Q000737:chemistry; D006801:Humans; D007150:Immunohistochemistry; D019344:Lactic Acid / Q000737:chemistry*; D008264:Macrophages / Q000166:cytology; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D008863:Microspheres; D011092:Polyethylene Glycols / Q000737:chemistry*; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D051381:Rats; D011923:Rats, Nude; D012828:Silicones / Q000737:chemistry; D013234:Stem Cells / Q000166:cytology*; D013524:Surgical Flaps; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds; D042461:Vascular Endothelial Growth Factor A / Q000737:chemistry*
chemical_list: D017077:Culture Media, Conditioned; D012828:Silicones; D042461:Vascular Endothelial Growth Factor A; D049452:Green Fluorescent Proteins; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D011092:Polyethylene Glycols; D003094:Collagen; D048271:Chitosan
keywords: Adipose-derived stem cell; Collagen-chitosan scaffold; PLGA/PEG microsphere; Soft tissue flap engineering; Vascular endothelial growth factor; Vascularization