title: Engineering of vascularized transplantable bone tissues: induction of axial vascularization in an osteoconductive matrix using an arteriovenous loop.
abstract: BACKGROUND
  Vascularization remains an obstacle to engineering of larger volume bone tissues. Our aim was to induce axial vascularization in a processed bovine cancellous bone (PBCB) matrix using an arteriovenous (AV) loop (artery, vein graft, and vein).
  
  
  METHODS
  Custom-made PBCB discs (9 x 5 mm) were implanted into rats. In group A (n = 19), the matrices were inserted into microsurgically constructed AV loops between the femoral vessels using a vein graft from the contralateral side. In group B (n = 19), there was no vascular carrier. The matrices were encased in isolation chambers. After 2, 4, and 8 weeks, the animals were perfused with India ink via the abdominal aorta. Matrices were explanted and subjected to histological and morphometric analysis. Results were compared with intravital dynamic micro & magnetic resonance imaging and scanning electron microscopy images of vascular corrosion replicas.
  
  
  RESULTS
  In group A, significant vascularization of the matrix had occurred by the 8th week. At this time, vascular remodeling with organization into vessels of different sizes was evident. Blood vessels originated from all 3 zones of the AV loop. Group A was significantly superior to group B in terms of vascular density and vascularization kinetics.
  
  
  CONCLUSIONS
  This study demonstrates for the first time successful vascularization of solid porous matrices by means of an AV loop. Injection of osteogenic cells into axially prevascularized matrices may eventually create functional bioartificial bone tissues for reconstruction of large defects.
authors.affiliation: Department of Plastic and Hand Surgery, University of Erlangen Medical Center, Erlangen, Germany. ulrich.kneser@chir.imed-erlangen.de
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kneser
authors.forename: Elias
authors.initials: E
authors.lastname: Polykandriotis
authors.forename: Jan
authors.initials: J
authors.lastname: Ohnolz
authors.forename: Kristina
authors.initials: K
authors.lastname: Heidner
authors.forename: Lucia
authors.initials: L
authors.lastname: Grabinger
authors.forename: Simon
authors.initials: S
authors.lastname: Euler
authors.forename: Kerstin U
authors.initials: KU
authors.lastname: Amann
authors.forename: Andreas
authors.initials: A
authors.lastname: Hess
authors.forename: Kay
authors.initials: K
authors.lastname: Brune
authors.forename: Peter
authors.initials: P
authors.lastname: Greil
authors.forename: Michael
authors.initials: M
authors.lastname: Stürzl
authors.forename: Raymund E
authors.initials: RE
authors.lastname: Horch
mesh_terms: D000818:Animals; D001705:Bioprosthesis; D001808:Blood Vessels / Q000648:ultrastructure; D018786:Bone Substitutes; D016025:Bone Transplantation; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000648:ultrastructure; D002417:Cattle; D018810:Magnetic Resonance Angiography; D008297:Male; D018919:Neovascularization, Physiologic; D011859:Radiography; D051381:Rats; D011917:Rats, Inbred Lew; D023822:Tissue Engineering; D014183:Transplantation, Heterologous
chemical_list: D018786:Bone Substitutes