title: In vivo regeneration of elastic lamina on fibroin biodegradable vascular scaffold.
abstract: OBJECTIVE
  There is an increasing need for vascular grafts in the field of surgical revascularization. Artificial grafts offer alternative strategies to autologous tissue, however, small caliber (diameter <6 mm)  vascular prosthesis are associated with a high incidence of thrombosis and early failure. Despite promising results, vascular tissue engineering is not yet a clinical reality due to the complexity of this approach. We aimed at investigating the use of fibroin, a biodegradable protein derived from silk, as an acellular vascular graft for in vivo recellularization.
  
  
  METHODS
  We produced small caliber fibroin matrices by electrospinning to replace small arterial segments. Electrospun fibroin scaffolds were implanted into the abdominal aorta of Lewis rats by end- to-end anastomosis. Seven days after implantation, fibroin matrices were recovered and processed for histological and immunohistochemical analysis.
  
  
  RESULTS
  Fibroin matrices allowed host cell infiltration, extracellular matrix remodeling, and ensured good patency of the grafts in the short term. Endothelial cells and smooth muscle cells were present in the explanted construct. Development of an elastic lamina adjacent to the lumen of the scaffold was observed with organization of intima and media layers. Vasa-vasorum were also present in the outer layer of the fibroin material.
  
  
  CONCLUSIONS
  Our results indicate that formation of vascular tissue containing elastin occurs already  at 7 days after implantation on fibroin scaffold without in vitro cellularization. The use of an acellular electrospun silk fibroin tubular scaffold could be a promising strategy for in vivo regeneration of vascular tissue in the clinical reality.
authors: Department of Biomedical Engineering and Department of Molecular Medicine, Mario Negri Institute, Bergamo, Italy.
authors: Irene
authors: I
authors: Cattaneo
authors: Marina
authors: M
authors: Figliuzzi
authors: Nadia
authors: N
authors: Azzollini
authors: Valentina
authors: V
authors: Catto
authors: Silvia
authors: S
authors: Farè
authors: Maria Cristina
authors: MC
authors: Tanzi
authors: Antonio
authors: A
authors: Alessandrino
authors: Giuliano
authors: G
authors: Freddi
authors: Andrea
authors: A
authors: Remuzzi
mesh_terms: D000818:Animals; D001807:Blood Vessel Prosthesis; D004549:Elastin / Q000502:physiology*; D042783:Endothelial Cells / Q000502:physiology; D005349:Fibroins; D032389:Myocytes, Smooth Muscle / Q000502:physiology; D051381:Rats; D012038:Regeneration / Q000502:physiology*; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds; D014654:Vascular Patency
chemical_list: D004549:Elastin; D005349:Fibroins