Uterine rejection after allogeneic uterus transplantation in the rat is effectively suppressed by tacrolimus.

OBJECTIVE: To evaluate the effects of the immunosuppressant tacrolimus on rejection of a transplanted uterus and on uterine expression of markers of inflammation and implantation. DESIGN: Experimental study. SETTING: University laboratory. ANIMAL(S): Female rats. INTERVENTION(S): Uteri from brown Norway rats were transplanted to Lewis rats, receiving either tacrolimus or no treatment. Sham groups underwent either hemihysterectomy or tacrolimus treatment. MAIN OUTCOME MEASURE(S): Gross morphology, histology, density of T-lymphocytes by immunohistochemistry, and mRNA levels of interleukin (IL)-1α, leukemia inhibitory factor (LIF), galectin-1, CD200, IL-15, interferon-inducible protein-10 (IP-10), and nuclear factor-κB (NF-κB) at 14 days' post-transplantation. RESULT(S): Nontreated uterine grafts showed rejection with necrosis. Sham groups and the tacrolimus-treated transplanted group exhibited normal uterine morphology with low numbers of T-lymphocytes in all uteri except in two out of seven uteri of the tacrolimus-treated transplant group. Uteri of the nontreated transplanted group showed elevated mRNA expression of IL-1α and IP-10 and reduced galectin-1, compared with the tacrolimus-treated transplanted group. There was no difference between any groups concerning uterine expression of LIF, NF-κB, IL-15, and CD200. CONCLUSION(S): Tacrolimus monotherapy suppresses rejection of an allotransplanted uterus and normalizes the expression of IL-1α and IP-10 and prevents T-lymphocyte infiltration.

Effects of immunosuppression by cyclosporine A on allogenic uterine transplant in the rat.

OBJECTIVE(S): Research on uterine transplantation (UTx) is conducted in preparation for its introduction in the human as a treatment for absolute uterine factor infertility. A major area of research in experimental animals is to ascertain that immunosuppressants that will be used at UTx do not negatively affect the potential of the uterus to implant an embryo and to carry a pregnancy to term. This study investigates the effects on a uterine transplant in the rat of the calcineurin inhibitor, cyclosporine A (CsA), on uterine morphology and expression patterns of some mediators involved in implantation/inflammation. STUDY DESIGN: Donor rats were of Brown Norway strain and recipients were of Lewis strain. The uterus was transplanted to an orthotopic site by vascular anastomosis. The recipients were given CsA (10mg/kg) sc once daily or no CsA until they were sacrificed at postoperative day 7. Syngenic transplanted Lewis rats were used as controls. Uteri were analyzed regarding histology, immunohistochemistry against T-cells and mRNA levels of the implantation/inflammation-related markers leukaemia inhibitory factor (LIF), galectin-1, CD200, interleukin (IL)-1α, and IL-15. RESULT(S): There was pronounced inflammation with abundance of CD8-lymphocytes in uterine grafts of non-CsA-treated animals and only mild inflammation in treated animals. The uterine mRNA levels of IL-1α were decreased after CsA in comparison to uteri of non-treated transplanted animals. The mRNA levels of galectin-1 were decreased in the rejected uteri and were higher in the CsA-treated. The levels of mRNA of IL-15 were lower in the syngenic transplanted group compared to the CsA-treated transplanted. There was no difference between the groups concerning mRNA levels of CD200, or LIF, with wide variation of the levels of the two latter mediators in all groups. CONCLUSION(S): Cyclosporine A suppresses rejection of an allogenic rat uterine transplant, with normalization of mRNA levels of the proinflammatory cytokine IL-1α and the glycan-binding protein galectin-1.

Pregnancy after syngeneic uterus transplantation and spontaneous mating in the rat.

BACKGROUND: Uterus transplantation (UTx) research aims towards the introduction of UTx as a treatment for uterine factor infertility. The rat model is the principal rodent model used and this study aims to assess the potential for pregnancy and to assess effects on pregnancy outcome. METHODS: Female Lewis rats underwent hysterectomy and received syngeneic uterine transplants (with one horn removed) by end-to-side anastomosis between the common iliac vessels of the recipient and the graft. The graft was placed in an orthotopic position with anastomosis to the upper part of the native uterine horn and vagina to allow for pregnancy by mating. Controls had only one uterine horn removed. Mating and pregnancy frequencies, successful deliveries and pup weight trajectory were compared. RESULTS: Pregnancy was achieved in rats after UTx with the pregnancy rate, number of pups and growth trajectory of pups being similar to controls. However, numbers of resorbed pregnancies and arrested parturitions were more common in the UTx group. CONCLUSIONS: A model for orthotopic UTx was developed and pregnancies with live offspring were for the first time demonstrated in the rat model of UTx. The model will be useful in future studies of fertility after UTx.

Experimental uterus transplantation.

BACKGROUND: Uterus transplantation (UTx) is developed in animal models as a future method to treat uterine factor infertility. METHODS: All published studies in the area of UTx research were identified. Aspects relating to surgery, cold-ischemia/reperfusion, rejection, immunosuppression, pregnancy, ethics and institutional requirements were examined. RESULTS: Uterus retrieval surgery has been solved in animals, including primates. Studies on cold-ischemia/reperfusion indicate an ischemic tolerance of >24 h. The transplantation procedure, with vascular anastomosis, has not been fully developed in animal models, indicated by frequent thrombosis formation. Pregnancies have only been reported in syngenic/auto-UTx animal models. Several ethical issues in relation to UTx, and requirements for a team that would be suitable to undertake human UTx, exist. CONCLUSION: Much research on UTx has been performed in appropriate animal models. Several aspects of the procedure have been optimized but some remain to be solved. It is predicted that the research will soon reach a stage that could merit introduction of human UTx as an experimental procedure.

Uterus transplantation: how far away from human trials?

Uterus transplantation is being developed as a possible future method to treat uterus factor infertility. This commentary gives an overview of the animal research that has been conducted in preparation for human uterus transplantation. In addition, requirements for further specific research activities within the field are identified. It is our prediction that uterus transplantation will be introduced as an experimental procedure in the human within a few years.

Uterus transplantation in the rat: model development, surgical learning and morphological evaluation of healing.

OBJECTIVE: Experimental uterus transplantation is a growing research field with the aim to develop a treatment for women with absolute uterus factor infertility. The potential risks of surgery and immunosuppressive treatment involved in uterus transplantation need to be identified and minimized in appropriate animal models before clinical trials commence. The aim of the present study was to develop and evaluate a model for uterus transplantation in the rat that can be reproduced and used in future studies concerning critical aspects of uterine function after transplantation. DESIGN: Animal study. SETTING: University Hospital. SAMPLE: Uterine tissue sampled at different post-operative time points after non-rejecting uterus transplantation in rats. METHODS: Adult, virgin female rats of inbred Lewis strain served as donors and recipients of uterine transplants. Two individuals with no previous microsurgical training performed the transplantations and learning curves were recorded. When transplant survival exceeded 70% for both surgeons, 15 animals were transplanted and grafted uteri were evaluated at 1, 7 and 21 days after surgery by assessment of morphology and enumeration of infiltrating neutrophilic granulocytes. MAIN OUTCOME MEASURES: Animal survival, graft survival, surgery times, uterine morphology, enumeration of infiltrating neutrophilic granulocytes. RESULTS: Both surgeons gained the necessary microsurgical skills needed to achieve above 70% transplant survival at a similar rate. The signs of post-operative inflammation on day one after transplantation were minor and further reduced at later time points. CONCLUSION: A reproducible model for uterus transplantation in the rat was developed, which can be used in future studies concerning uterine function after allogenic transplantation.

Transplantation of the uterus in sheep: methodology and early reperfusion events.

AIM: Uterine transplantation is developing into a clinical treatment for uterine factor infertility. An animal model with a similar uterus size and vessels to humans and with pregnancy extending over several months would be beneficial for research on uterine transplantation. The aim of this study was to develop and evaluate autotransplantation of the sheep uterus to an orthotopic position in the pelvis. METHODS: Female sheep (n=7) were subjected to laparotomy with the uterus and its vascular supply and drainage being surgically isolated. The excised uterus was kept ex vivo at +4 degrees C for 60 min and then autotransplanted with vascular end-to-side anastomoses to the external iliac vessels. The effects of uterine blood-reperfusion were assessed by measurements of pCO(2), pO(2), lactate and pH in uterine venous blood. Uterine contractility and histology was assessed after 3 h of reperfusion. RESULTS: Reperfusion of blood was observed in five out of seven transplanted uteri. The pCO(2)/pO(2)-ratio and the lactate level were initially elevated but decreased and became normal after 60 min. After 3 h of reperfusion there was a visible tissue blood flow and spontaneous uterine contractions were seen. Histological analysis revealed a mild inflammation, but no edema or stasis. CONCLUSIONS: This study demonstrates that the sheep uterus can successfully be autotransplanted to an orthotopic position with novel vascular connections. This model is suitable for future experiments studying long-term results concerning uterine viability and pregnancy using a transplanted uterus of similar size to the human uterus.

Transplantation of the uterus in the sheep: oxidative stress and reperfusion injury after short-time cold storage.

OBJECTIVE: To study the effects of cold ischemia and reperfusion after transplantation of the sheep uterus and to compare the preservation solution Perfadex (Vitrolife, Mölndal, Sweden) with Ringer's acetate. DESIGN: Experimental animal study. SETTING: University hospital. ANIMAL(S): Adult, female sheep. INTERVENTION(S): One uterine horn with the common uterine cavity and cervix of sexually mature ewes was auto-transplanted after 1 hour of cold ischemic storage in either Perfadex (n = 5) or Ringer's acetate (n = 5). During 3 hours of reperfusion, uterine venous blood was collected and analyzed for several parameters that were indicative of oxidative stress and reperfusion injury. A biopsy was taken for histological analysis at the end of the experiment. MAIN OUTCOME MEASURE(S): Lipid peroxidation and ascorbyl radicals in uterine venous blood during reperfusion. Light microscopy and quantification of neutrophils in tissue after 3 hours of reperfusion. RESULT(S): A decline in pH and a rise in lactate and pCO(2)-pO(2), as well as an elevation of antioxidant capacity, lipid peroxidation, and intensity of ascorbyl radical electron spin resonance signal, was found that was more prominent after storage in Ringer's acetate. The histological analysis revealed mild inflammation in both study groups. CONCLUSION(S): Short-time cold ischemic storage of the sheep uterus does not induce any severe reperfusion damage, but the use of the protective buffer Perfadex decreases oxidative stress and inflammation when compared with a more simple solution.

Uterus transplantation: where do we stand today and where should we go?

If transplantation of the uterus is developed into a safe method with a reasonable chance for the patient to carry an uneventful pregnancy, this procedure could become a feasible fertility treatment for women with absolute uterus factor infertility. The activity in this research field is growing and during the past 5 years several reports have been published. In this brief review the authors summarize the state of research in this field and also speculate on what might lie ahead.

Auto-transplantation of the uterus in the domestic pig (Sus scrofa): Surgical technique and early reperfusion events.

AIM: To develop a method for auto-transplantation of the uterus in the pig and to evaluate the early reperfusion events after short-term cold ischemia. METHODS: The bicornate uterus, with the cervix but without ovaries, was dissected and isolated with its bilateral feeding and draining vessels. The uterine arteries were cannulated in situ and the uterus was flushed with heparinized Ringer Acetate. It was stored at 4 degrees C for 1-2 h during continuous flushing. The uterus was then placed in its original pelvic position and the uterine arteries and veins were anastomosed end-to-end to their origin. During approximately 100 min of reperfusion, blood samples and tissue biopsies were taken for monitoring of reperfusion events and detection of ischemia-reperfusion injuries. RESULTS: Out of 19 auto-transplanted pigs, seven were considered well flushed and were kept for cold ischemia. Of these seven, four showed satisfactory reperfusion judged by change in gross appearance and presence of appropriate venous blood flow. Analysis of blood-gas and metabolite parameters and histology indicated that at least two of these transplants were well reperfused, with no severe ischemia-reperfusion injuries. CONCLUSION: In this first report ever on auto-transplantation of the pig uterus it is demonstrated that an acceptable reperfusion can be achieved. Furthermore, it is suggested that because of the large total size of the pig uterus with long uterine horns and the small size of the vessels available for re-anastomosis, the pig is a fairly difficult model for further studies on transplantation of the uterus.

Uterine transplantation.

Uterine factor infertility is either due to congenital malformation or acquired. Most women with uterine factor infertility have no chance to become genetic mothers, except by the use of gestational surrogacy. The logical but radical approach for treatment would be replacement of the unfunctional or absent uterus. Uterine transplantation could allow these women to become both genetic and gestational mothers. The present work reviews the existing literature on the history and recent development around this topic. We also briefly describe a newly developed model for heterotopic uterine transplantation in the mouse, in which pregnancies have been accomplished. Some specific issues that are required to be solved prior any further attempts to transplant the uterus in humans are also addressed.

Transplantation of the uterus.

Most women with uterine factor infertility have today no prospect of carrying a pregnancy to term. The development of a method for transplantation of the human uterus would be a means for many of these women to become both genetic and gestational mothers. In this article we review the literature concerning the history and recent development in the area of uterine transplantation. We describe our newly developed model for heterotopic uterine transplantation in the mouse, which we are using for studies of pregnancy outcome and rejection mechanisms. We also address some of the specific questions that need to be solved before attempts to transplant the human uterus should be performed.