Caiza A. Wranning

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.

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.

Fertility after autologous ovine uterine-tubal-ovarian transplantation by vascular anastomosis to the external iliac vessels

BACKGROUND Transplantation of the uterus has been suggested as a treatment of uterine factor infertility. This study investigates whether the sheep uterus can resume its capacity to harbour normal pregnancies after autotransplantation by vascular anastomosis. METHODS From 14 ewes, the uterus, excluding one uterine horn, was isolated along with its oviduct and ovary and preserved ex vivo and then transplanted back with end-to-side anastomosis of the vessels of the graft to the external iliac vessels. After recovery, the ewes underwent surgical examination and serum progesterone measurements to ascertain healing and ovarian activity. Afterwards, five autotransplanted and five control ewes were placed with a ram for mating. Caesarean sections were performed before the estimated term of pregnancy and data on fetal measures were compared. RESULTS Of the 14 ewes, seven survived surgery with ovarian activity intact and grafts showing normal appearance. Mating occurred in four of five transplanted ewes and in five out of five controls, and three transplanted animals and five control animals conceived. In one transplanted ewe, torsion of the uterus was observed after spontaneous initiation of labour. Foeti from transplanted mothers were comparable in size to those of controls. CONCLUSIONS Despite the encountered complications, this is the first report to demonstrate fertility and pregnancies going to term after autotransplantation of the uterus in an animal of a comparable size to the human.

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.

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.

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.

Rejection of allogenic uterus transplant in the mouse: time-dependent and site-specific infiltration of leukocyte subtypes

BACKGROUND Animal models of uterus transplantation are being developed ahead of a possible treatment for absolute uterus infertility in women. Our knowledge of inflammatory cell involvement in acute rejection of a uterus transplant is limited; therefore, we examined the pattern of invasion of leukocyte subtypes into an allogeneic uterus transplant. METHODS The uterus and its vasculature were removed from BALB/c mice and transplanted into C57Bl/6 recipient mice at a heterotopic position, with the native uterus left in situ. Both uteri were removed on post-operative day 2 (D2, n = 5), D5 (n = 5) and D10 (n = 6). Immunohistochemistry for neutrophilic granulocytes, macrophages, cytotoxic CD8(+) T-cells, CD4(+) T-helper cells and B-cells was performed and cell density was evaluated in both myometrium and endometrium. RESULTS Neutrophil density was increased in graft versus native uteri at D5 and D10 in myometrium and D10 in endometrium, and in endometrium was higher in the D5 than D2 graft (all P < 0.05). Infiltration of macrophages occurred from D2 in myometrium and from D5 in endometrium (P < 0.05, graft versus native). Density of CD8(+) cytotoxic T-cells increased in the graft versus native uteri at D5 in both uterine layers and for the graft versus D2 density (P < 0.01). In contrast, CD4(+) T-helper cells increased only transiently in graft endometrium at D5 (P < 0.05). Overall CD19(+) B-cell density was low, with no time-dependent changes in graft myometrium or endometrium. CONCLUSIONS Acute rejection of an allogeneic uterus transplant in the mouse involves influx of predominately neutrophils, macrophages, CD8(+) T-cells and CD4(+) T-cells between D2 and D5 post-operatively.

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.

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.