Decellularization of the Porcine Ear Generates a Biocompatible, Nonimmunogenic Extracellular Matrix Platform for Face Subunit Bioengineering.

OBJECTIVE: The purpose of this study was to assess whether perfusion-decellularization technology could be applied to facial grafts. BACKGROUND: Facial allotransplantation remains an experimental procedure. Regenerative medicine techniques allow fabrication of transplantable organs from an individual's own cells, which are seeded into extracellular matrix (ECM) scaffolds from animal or human organs. Therefore, we hypothesized that ECM scaffolds also can be created from facial subunits. We explored the use of the porcine ear as a clinically relevant face subunit model to develop regenerative medicine-related platforms for facial bioengineering. METHODS: Porcine ear grafts were decellularized and histologic, immunologic, and cell culture studies done to determine whether scaffolds retained their 3D framework and molecular content; were biocompatible in vitro and in vivo, and triggered an anti-MHC immune response from the host. RESULTS: The cellular compartment of the porcine ear was completely removed except for a few cartilaginous cells, leaving behind an acellular ECM scaffold; this scaffold retained its complex 3D architecture and biochemical components. The framework of the vascular tree was intact at all hierarchical levels and sustained a physiologically relevant blood pressure when implanted in vivo. Scaffolds were biocompatible in vitro and in vivo, and elicited no MHC immune response from the host. Cells from different types remained viable and could even differentiate at the scale of a whole-ear scaffold. CONCLUSIONS: Acellular scaffolds were produced from the porcine ear, and may be a valuable platform to treat facial deformities using regenerative medicine approaches.

Single-Artery Human Ear Graft Procurement: A Simplified Approach.

In the field of experimental facial vascularized composite tissue allotransplantation, a human auricular subunit model, pedicled on both superficial temporal and posterior auricular arteries, was described. Clinical cases of extensive auricular replantation, however, suggested that a single artery could perfuse the entire flap. In this study, variants of this single-pedicle approach have been studied, aiming to develop a more versatile replantation technique, in which the question of venous drainage has also been addressed. For arterial perfusion study, the authors harvested 11 auricular grafts, either on a single superficial temporal artery pedicle (n = 3) or a double superficial temporal and posterior auricular artery pedicle (n = 8). The authors then proceeded to selective barium injections, in the superficial temporal, posterior auricular, or both superficial temporal and posterior auricular arteries. Arteriograms were acquired with a micro-computed tomographic scan and analyzed on three-dimensionally reconstructed images. Venous drainage was investigated in eight hemifaces, carefully dissected after latex injection. Observations showed a homogenous perfusion of the whole auricle in all arterial graft variants. Venous drainage was highly variable, with either a dominant superficial temporal vein (37.5 percent), dominant posterior auricular vein (12.5 percent), or co-dominant trunks (50 percent). The authors demonstrated that auricular subunit vascularized composite tissue allotransplantation can be performed on a single artery, relying on the dynamic intraauricular anastomoses between superficial temporal artery and posterior auricular branches. Potentially, this vascular versatility is prone to simplify the subunit harvest and allows various strategies for pedicle selection. Venous drainage, however, remains inconstant and thus the major issue when considering auricular transplantation. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.