A preclinical canine model for composite tissue transplantation.

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.