In this study, the authors present a modification of the arteriovenous loop model that combines extrinsic and intrinsic vascularization modes to enhance vascularization of bioartificial matrices.
An arteriovenous loop was created in the medial thighs of 24 rats. The loop was placed in a newly developed titanium chamber, which was fabricated with an electron beam melting facility, and was embedded in a hydroxyapatite/β-tricalcium phosphate/fibrin matrix. At the explantation time points (2, 4, 6, and 8 weeks), constructs were perfused by differently colored dyes to determine the amount of tissue vascularized by either the intrinsic or the extrinsic vascular pathway. Specimens were investigated by means of micro–computed tomography and histologic and morphometric analysis.
Although there was an equal number of blood vessels originating from the center and the periphery, 83 percent of all vessels displayed a connection to the arteriovenous loop already at 2 weeks. There was a continuous increase of the relative proportion of vessels connected to the arteriovenous loop over time detectable. At 8 weeks, communications between the newly formed vessels and the arteriovenous loop were visible in 97 percent of all vessels.
This study demonstrates for the first time the enhancement of angiogenesis in an axially vascularized tissue by an additional extrinsic vascular pathway. By 2 weeks, both pathways showed connections, allowing transplantation of the entire construct using the arteriovenous loop pedicle. This approach will allow for reduction of the time interval between arteriovenous loop implantation and transplantation into the defect site and limitation of operative interventions.
From the Department of Plastic and Hand Surgery, University of Erlangen Medical Center, and the Institute of Science and Technology of Metals, University of Erlangen-Nürnberg.
Received for publication March 5, 2011; accepted June 23, 2011.
Presented in part at the Tissue Engineering and Regenerative Medicine International Society European Union Congress 2010, in Galway, Ireland, June 13 through 17, 2010, and at the 41st Congress of the German Society for Plastic, Reconstructive and Aesthetic Surgery, in Dresden, Germany, September 15 through 18, 2010.
Disclosure: The authors have no competing financial interests to declare.
Andreas Arkudas, M.D.; Department of Plastic and Hand Surgery, University of Erlangen Medical Center, Krankenhausstrasse 12, D-91054 Erlangen, Germany, firstname.lastname@example.org