A Heterotopic Primate Model for Facial Composite Tissue Transplantation

Abstract

The purpose of this study was to develop a nonhuman primate model for heterotopic composite tissue facial transplantation in which to study the natural history of facial transplantation and evaluate immunosuppressive regimens.A composite oromandibular facial segment transplant based on the common carotid artery was evaluated. Flaps from 7 cynomolgus monkeys were transplanted to the groins of 7 recipients at the superficial femoral artery and vein. The immunosuppressive regimen consisted of thymoglobulin, rapamycin, and tacrolimus. Allograft survival ranged from 6 to 129 days. Histology performed in the long-term survivor at the time of necropsy revealed extensive inflammation and necrosis of the allograft skin; however, muscle and bone elements were viable, with minimal inflammation. This heterotopic facial transplantation model avoids the potential morbidity of mandibular resection and orthotopic facial transplantation. Our work also concurs with the work of other groups who found that the skin component is the most antigenic.

Facial Subunit Composite Tissue Allografts in Nonhuman Primates: I. Technical and Immunosuppressive Requirements for Prolonged Graft Survival

“…Recently, Silverman et al described a facial subunit composite tissue allotransplantation model in a nonhuman primate with frequent immunosuppression complications, early graft losses (presumed technical failures), and rejection of surviving allografts. 18 Despite the potential benefits of a nonhuman primate model, these experiences demonstrate the difficulties in establishing a reliable model.…”

An Anatomical Study of External Carotid Artery Vascular Territories in Face and Midface Flaps for Transplantation

“…Animal models have demonstrated reliable transfer of hemifacial flaps based on the external carotid artery system. 10,11 Siemionow et al propose dissection of human face flaps in a subgaleal, sub-superficial musculoaponeurotic system (SMAS) plane that includes the parotid gland to ensure inclusion of the superficial temporal artery. 12,13 A variation of this technique begins with a coronal incision and progresses inferiorly, providing increased pedicle length.…”

Swine Hemi-Facial Composite Tissue Allotransplantation: A Model to Study Immune Rejection

“…It is always expensive and a lot of work to use big animals such as swine and primate as a model. Silverman and colleagues recently developed a heterotopic nonhuman primate facial CTA model including skin, masseter and a portion of pterygoid muscle, and mandible bone [22]. The results indicated this primate allograft model showed a big variation of allograft survival.…”