Modified uterine transplant procedure in the sheep model.

Abstract Study Objective The purpose of this project is to develop a uterine transplant procedure in the sheep model that may be suitable for human uterine transplants. Design Pilot study (Canadian Task Force classification II-2). Setting University De La Salle Bogota, Colombia. Patients A total of 10 sexually matured sheep undergoing uterine allotransplantation. Interventions Uterine transplantation through a minilaparotomy incision with the application of a 900-500 modified Mobius retractor device. Measurements and Main Results The short-term effects of warm and cold tissue ischemia were quantified and uterine tissue reperfusion was analyzed after vascular reanastomosis. The ovine model was preferred since the anatomical landmarks and vascular anatomy are comparable to the human with the exception of a bicornuate uterus in the subprimate model. A modified surgical procedure was applied to our uterine allotransplanted sheep (n = 10) and tissue rejection was managed with cyclosporine therapy. A total abdominal hysterectomy without oophorectomy was performed and a cold ischemic time of 45 minutes was recorded. The uterine arteries and veins were reapproximated using a continuous end-to-end noninterlocking approach. Vascular patency and uterine tissue viability were assessed by histological studies. Complete tissue reperfusion of blood was achieved in our 10 animals within 30 seconds after vascular reanastomosis without evidence of arterial or venous thrombosis. At 6 months postuterine transplantation, hysterectomies were performed documenting viable uterine tissue and vascular patency in 6 out of the 10 uterine allotransplants. The site of uterine vessel reanastomosis was patent and histological studies indicated neovascularization with presence of smooth muscle and glandular endometrial tissue. Conclusion We have developed a modified procedure that has allowed us to perform successful uterine transplants in the sheep model. This is the first reported case in the literature documenting a successful procedure of uterine allotransplantation in the ewe. Our pilot study demonstrates that the ewe is an excellent model for uterine transplant research and with further studies; we plan to demonstrate that a pregnancy can be achieved after a successful uterine transplant.