A preclinical canine model for composite tissue transplantation

Abstract

The feasibility of composite tissue allografts (CTAs) has been demonstrated by the successful transplantation of the hand, abdomen, and face. However, the survival of these transplants depends on immunosuppression. Our laboratory is interested in achieving tolerance to decrease the risks associated with the use of chronic immunosuppression. The purpose of this experiment was to develop a large-animal model for CTA. Four canine flaps were autotransplanted to examine the use of a myocutaneous rectus flap based on the deep inferior epigastric vessels. Five CTA transplants were performed between dog leukocyte antigen (DLA)-identical littermates without posttransplant immunosuppression. The allografts were followed clinically and underwent routine biopsies. The anatomic dissections and autotransplants were all successful and revealed that the flap could be divided into two separate components. Skin was perfused by the superficial epigastric artery. Rectus muscle was perfused by the deep inferior epigastric system. This allowed the allografts to be transplanted as muscle or skin or with both components based on the external iliac artery and veins. The DLA-identical littermates rejected the allografts in 15 to 30 days. This study demonstrated the versatility of the myocutaneous rectus flap for use in canines as CTA models.

Figure 1

(A) Preoperative markings on donor dog abdomen. (B) Donor flap inset into recipient dog's groin.

Figure 2

(A) Vascular anastamosis of recipient femoral artery and vein (f) to deep inferior (d) and superficial (s) epigastric vessels of allograft. (B) Intercostal nerve (n) attachment.

Figure 3

(A) Composite tissue allograft harvested on deep inferior epigastric (d) artery and vein. (B) Alternate blood vessels from external iliac artery and vein (i). (C) Deep inferior epigastric and superior inferior epigastric (s) vasculature supplying graft tissue of donor dog.

Figure 4

Progression of rejecting allotransplant in recipient dog. (A) Signs of early rejection and swelling 12 days postoperatively. (B) Further evidence of acute rejection on day 22. (C) Complete necrosis on day 30.

Figure 5

Histology of allograft skin (A) and muscle (B) showing lymphocytic infiltration and necrosis taken on postoperative day 22.