Experimental models of composite tissue allograft transplants

Abstract

Composite tissue allotransplantation has been recently introduced as a potential clinical treatment for complex reconstructive procedures including traumatic injuries, cancer ablative surgeries, or extensive tissue loss secondary to burns. Composite tissue allografts (CTAs) consist of heterogeneous tissues including skin, fat, muscle, nerves, lymph nodes, bone, cartilage, ligaments, and bone marrow with different antigenicities. Thus, composite tissue structure is considered to be more immunogenic than solid organ transplants. In this article, we present the experimental applications of CTA transplantation. To study the mechanisms of CTA acceptance and rejection, different experimental models, strategies, and different immunosuppressive protocols were used.

Keywords: Composite tissue allotransplantation; experimental models; face; limb; vascularized bone.

Figure 1

Appearance of the transplanted hind limb (LBN to LEW) at day 65 under combined CsA/αβ-TCR mAb therapy showing no signs of rejection.

Figure 2

Composite vascularized skin/bone graft model. (A) Anatomy of harvested composite vascularized skin/bone graft. (B) Composite vascularized skin/bone graft at day 60 posttransplant revealed complete survival.

Figure 3

Vascularized skin (groin) allograft transplant model. (A) Appearance of the harvested vascularized skin allograft from semi-allogeneic LBN donors. (B) Vascularized groin skin transplants based on the femoral vessels were performed between semi-allogeneic LBN donors and Lewis recipients (early posttransplant view). (C) The recipient of skin (groin) allograft 150 days after transplant shows no sign of rejection under low-dose cyclosporin A monotherapy.

Figure 4

The full face/scalp allograft transplantation model. (A) Full face/scalp flaps including the external ears and scalp, based on the common carotid artery and external jugular vein, were harvested from the donors. (B) Immediate posttransplant view of the full face/scalp allograft recipient. Transplantation was performed between full-allogeneic ACI donors and Lewis recipients. (C) Late posttransplant views of full face/scalp allograft recipient on low dose of cyclosporin A monotherapy at day 200 showing no signs of rejection.

Figure 5

Hemiface/mandible/tongue allotransplantation model. (A) The outer aspects of the flap. Mandibular tooth and tongue are seen. (B) The inner aspect of the flap. Common carotid artery, external jugular vein, tongue, mandibular tooth, and mandibular condyle are seen. (C) Appearance of the hemiface/mandible/tongue allograft transplant at day 150 posttransplant (LBN to LEW).