Engineering of vascularized transplantable bone tissues: induction of axial vascularization in an osteoconductive matrix using an arteriovenous loop.
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.
Kneser
Ulrich
U
Department of Plastic and Hand Surgery, University of Erlangen Medical Center, Erlangen, Germany. ulrich.kneser@chir.imed-erlangen.de
Polykandriotis
Elias
E
Ohnolz
Jan
J
Heidner
Kristina
K
Grabinger
Lucia
L
Euler
Simon
S
Amann
Kerstin U
KU
Hess
Andreas
A
Brune
Kay
K
Greil
Peter
P
Stürzl
Michael
M
Horch
Raymund E
RE
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
D018786:Bone Substitutes