title: Tissue-engineered vascular grafts: does cell seeding matter?
abstract: OBJECTIVE
  Use of tissue-engineered vascular grafts (TEVGs) in the repair of congenital heart defects provides growth and remodeling potential. Little is known about the mechanisms involved in neovessel formation. We sought to define the role of seeded monocytes derived from bone marrow mononuclear cells (BM-MNCs) on neovessel formation.
  
  
  METHODS
  Small diameter biodegradable tubular scaffolds were constructed. Scaffolds were seeded with the entire population of BM-MNC (n = 15), BM-MNC excluding monocytes (n = 15), or only monocytes (n = 15) and implanted as infrarenal inferior vena cava (IVC) interposition grafts into severe combined immunodeficiency/bg mice. Grafts were evaluated at 1 week, 10 weeks, or 6 months via ultrasonography and microcomputed tomography, as well as by histologic and immunohistochemical techniques.
  
  
  RESULTS
  All grafts remained patent without stenosis or aneurysm formation. Neovessels contained a luminal endothelial lining surrounded by concentric smooth muscle cell layer and collagen similar to that seen in the native mouse IVC. Graft diameters differed significantly between those scaffolds seeded with only monocytes (1.022 +/- 0.155 mm) and those seeded without monocytes (0.771 +/- 0.121 mm; P = .021) at 6 months.
  
  
  CONCLUSIONS
  Monocytes may play a role in maintaining graft patency. Incorporation of such findings into the development of second-generation TEVGs will promote graft patency and success.
authors.affiliation: Yale-New Haven Hospital, New Haven, CT 06510, USA; Yale University School of Medicine, New Haven, CT 06510, USA. tamar.mirensky@yale.edu
authors.forename: Tamar L
authors.initials: TL
authors.lastname: Mirensky
authors.forename: Narutoshi
authors.initials: N
authors.lastname: Hibino
authors.forename: Rajendra F
authors.initials: RF
authors.lastname: Sawh-Martinez
authors.forename: Tai
authors.initials: T
authors.lastname: Yi
authors.forename: Gustavo
authors.initials: G
authors.lastname: Villalona
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Shinoka
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Breuer
mesh_terms: D000818:Animals; D001807:Blood Vessel Prosthesis; D049109:Cell Proliferation; D004195:Disease Models, Animal; D005260:Female; D006085:Graft Survival; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D016513:Mice, SCID; D009000:Monocytes / Q000166:cytology*; D011474:Prosthesis Design; D023822:Tissue Engineering; D054457:Tissue Scaffolds; D014654:Vascular Patency / Q000502:physiology; D014682:Vena Cava, Inferior / Q000166:cytology / Q000637:transplantation*