Preclinical report on allogeneic uterus transplantation in non-human primates

A new bicornuate model of rat uterus transplantation

INTRODUCTION

Uterus transplantation has revolutionized reproductive medicine for women with absolute uterine factor infertility, resulting in more than 40 reported successful live births worldwide to date. Small animal models are pivotal to refine this surgical and immunological challenging procedure aiming to enhance safety for both the mother and the child.

MATERIAL AND METHODS

We established a syngeneic bicornuate uterus transplantation model in young female Lewis rats. All surgical procedures were conducted by an experienced and skilled microsurgeon who organized the learning process into multiple structured steps. Animals underwent meticulous preoperative preparation and postoperative care. Transplant success was monitored by sequential biopsies, monitoring graft viability and documenting histological changes long-term.

RESULTS

Bicornuate uterus transplantation were successfully established achieving an over 70% graft survival rate with the passage of time. The bicornuate model demonstrated safety and feasibility, yielding outcomes comparable to the unicornuate model in terms of ischemia times and complications. Longitudinal biopsies were well-tolerated, enabling comprehensive monitoring throughout the study.

CONCLUSIONS

Our novel bicornuate rat uterus transplantation model provides a distinctive opportunity for sequential biopsies at various intervals after transplantation and, therefore, comprehensive monitoring of graft health, viability, and identification of potential signs of rejection. Furthermore, this model allows for different interventions in each horn for comparative studies without interobserver differences contrary to the established unicornuate model. By closely replicating the clinical setting, this model stands as a valuable tool for ongoing research in the field of uterus transplantation, promoting further innovation and deeper insights into the intricacies of the uterus transplant procedure.

Molecular Basis of Müllerian Agenesis Causing Congenital Uterine Factor Infertility-A Systematic Review

Infertility affects around 1 in 5 couples in the world. Congenital absence of the uterus results in absolute infertility in females. Müllerian agenesis is the nondevelopment of the uterus. Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is a condition of uterovaginal agenesis in the presence of normal ovaries and the 46 XX Karyotype. With advancements in reproductive techniques, women with MA having biological offspring is possible. The exact etiology of MA is unknown, although several genes and mechanisms affect the development of Müllerian ducts. Through this systematic review of the available literature, we searched for the genetic basis of MA. The aims included identification of the genes, chromosomal locations, changes responsible for MA, and fertility options, in order to offer proper management and counseling to these women with MA. A total of 85 studies were identified through searches. Most of the studies identified multiple genes at various locations, although the commonest involved chromosomes 1, 17, and 22. There is also conflicting evidence of the involvement of various candidate genes in the studies. The etiology of MA seems to be multifactorial and complex, involving multiple genes and mechanisms including various mutations and mosaicism.

Uterus transplantation: from research, through human trials and into the future

Women suffering from absolute uterine factor infertility (AUFI) had no hope of childbearing until clinical feasibility of uterus transplantation (UTx) was documented in 2014 with the birth of a healthy baby. This landmark accomplishment followed extensive foundational work with a wide range of animal species including higher primates. In the present review, we provide a summary of the animal research and describe the results of cases and clinical trials on UTx. Surgical advances for graft removal from live donors and transplantation to recipients are improving, with a recent trend away from laparotomy to robotic approaches, although challenges persist regarding optimum immunosuppressive therapies and tests for graft rejection. Because UTx does not involve transplantation of the Fallopian tubes, IVF is required as part of the UTx process. We provide a unique focus on the intersection between these two processes, with consideration of when oocyte retrieval should be performed, whether, and for whom, preimplantation genetic testing for aneuploidy should be used, whether oocytes or embryos should be frozen and when the first embryo transfer should be performed post-UTx. We also address the utility of an international society UTx (ISUTx) registry for assessing overall UTx success rates, complications, and live births. The long-term health outcomes of all parties involved-the uterus donor (if live donor), the recipient, her partner and any children born from the transplanted graft-are also reviewed. Unlike traditional solid organ transplantation procedures, UTx is not lifesaving, but is life-giving, although as with traditional types of transplantation, costs, and ethical considerations are inevitable. We discuss the likelihood that costs will decrease as efficiency and efficacy improve, and that ethical complexities for and against acceptability of the procedure sharpen the distinctions between genetic, gestational, and social parenthood. As more programs wish to offer the procedure, we suggest a scheme for setting up a UTx program as well as future directions of this rapidly evolving field. In our 2010 review, we described the future of clinical UTx based on development of the procedure in animal models. This Grand Theme Review offers a closing loop to this previous review of more than a decade ago. The clinical feasibility of UTx has now been proved. Advancements include widening the criteria for acceptance of donors and recipients, improving surgery, shortening time to pregnancy, and improving post-UTx management. Together, these improvements catalyze the transition of UTx from experimental into mainstream clinical practice. The procedure will then represent a realistic and accessible alternative to gestational surrogacy for the treatment of AUFI and should become part of the armamentarium of reproductive specialists worldwide.

Experimental Static Cold Storage of the Rat Uterus: Protective Effects of Relaxin- or Erythropoietin-Supplemented HTK-N Solutions

Uterus transplantation (UTx) is the only treatment method for women with absolute uterine infertility. Currently, the number of grafts retrieved from deceased donors is increasing; hence, prolonged cold ischemia time is inevitable. Thus, this study was designed to assess the effect of the novel relaxin (RLN)- or erythropoietin (EPO)-supplemented Custodiol-N (HTK-N) solutions in an experimental uterus static cold storage (SCS) model. A total of 15 Sprague Dawley rats were used. Uterus horns were randomly assigned into three groups (n = 10/group). SCS was performed by keeping samples at 4 °C in HTK-N solution without or with different additives: 10 IU/mL EPO or 20 nM RLN. Tissue samples were taken after 8 and 24 h of preservation. Uterine tissue histology, and biochemical and immunohistochemical markers were analyzed. No significant differences in SCS-induced tissue damage were observed between groups after 8 h of preservation. Uterine tissue histology, MDA, SOD levels and the TUNEL-positive cell number showed severe damage in HTK-N without additives after 24 h of preservation. This damage was significantly attenuated by adding RLN to the preservation solution. EPO showed no favorable effect. Our study shows that RLN as an additive to an HTK-N solution can serve as an effective uterine tissue preservative in the uterus SCS setting.

Involving Animal Models in Uterine Transplantation

Background

Absolute uterine factor infertility affects 0. 2% women of childbearing age around the world. Uterine transplantation (UTx) is a promising solution for many of them since the first birth from UTx was described by the Swedish team in 2014. The success of Utx in humans has become possible after a systematic and meticulous approach involving years of research on animal models. To date, more than 80 UTx procedures have been performed worldwide and 30 children were born.

Material and Method

This review summarizes the research preparation conducted in animals before beginning UTx in humans. It focuses on the advantages and limits of each animal model, their place in surgical training, and current contribution in research to improve UTx successes in humans. The different steps in the process of UTx have been analyzed, such as imaging, surgery, ischemia-reperfusion effects, rejection markers, immunosuppressive treatment, and pregnancy.

Conclusion

Animal models have played an essential role in the implementation of UTx, which is a highly complex procedure. While respecting the 3R requirements (replacement, refinement, and reduction), the surgical training using large animal models, such as notably ewes remain irreplaceable for teams wishing to initiate a UTx program. Furthermore, animal models are still mandatory in current research to improve the success rates of UTx in humans as well as to reduce the morbidity associated with this experimental infertility treatment.

Uterine transplantation: legal and regulatory implications in England

Uterus transplantation (UTx) is fast evolving from an experimental to a clinical procedure, combining solid organ transplantation with assisted reproductive technology. The commencement of the first human uterus transplant trial in the United Kingdom leads us to examine and reflect upon the legal and regulatory aspects closely intertwined with UTx from the process of donation to potential implications for fertility treatment and the birth of the resultant child. As the world's first ephemeral transplant, the possibility of organ restitution requires consideration and is discussed herein. TWEETABLE ABSTRACT: Uterine transplantation warrants a closer look at the legal frameworks on fertility treatment and transplantation in England.

Uterine Transplantation: Review of Livebirths and Reproductive Implications

Uterine transplantation (UTx) is a fertility restoring treatment for women with absolute uterine factor infertility. At a time when there is no question of the procedure's feasibility, and as the number of livebirths begins to increase exponentially, various important reproductive, fetal, and maternal medicine implications have emerged. Detailed outcomes from 17 livebirths following UTx are now available, which are reviewed herein, along with contextualized extrapolation from pregnancy outcomes in other solid organ transplants. Differences in recipient demographics and reproductive aspirations between UTx and other transplant recipients make extrapolating management strategies and outcomes in other solid organ transplants inappropriate. Whereas preterm delivery remains prominent, small for gestational age or hypertensive disorders do not appear to be as prevalent following UTx when compared to other solid organ transplants. Given the primary objective of undertaking UTx is to achieve a livebirth, publication of reproductive outcomes is essential at this early stage, to reflect on and optimize the management of future cases.

The costs of human uterus transplantation: a study based on the nine cases of the initial Swedish live donor trial

STUDY QUESTION

What are the costs of live donor uterus transplantation in a European setting?

SUMMARY ANSWER

The total costs for preoperative investigations, including IVF, and live donor uterus transplantation including postoperative costs for 2 months, were calculated to be €74 564 (mean), with the costs of recipient being somewhat higher than for donor and the cost components of total costs distributed between sick leave (25.7%), postoperative hospitalization (17.8%), surgery (17.1%), preoperative investigations (15.7%), anaesthesia (9.7%), drugs (7.8%), tests after surgery (4.0%) and for re-hospitalization (2.2%).

WHAT IS KNOWN ALREADY

Uterus transplantation has proved to be successful by demonstrations of live births, both after live donor and deceased donor procedures. The transplantation is considered as a complex and expensive infertility treatment. There exist no analyses of costs involved in uterus transplantation.

STUDY DESIGN, SIZE, DURATION

This prospective cohort study included nine uterus transplantations procedures, performed in Sweden in 2013. Study duration of this health economic study included 6-12 months of pre-transplantation investigations and the time interval from transplantation to 2 months after.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Nine triads of uterus recipient, partner of recipient and uterus donor participated. All prospective recipients were in stable relationships and performed IVF with their partners before transplantation. The nine donors were relatives or family friends. The recipients and donors underwent pre-transplantation investigations with imaging, laboratory tests and psychological/medical screening prior to transplantation. Transplantation was by laparotomy in both donor and recipient. Standard immunosuppression and postoperative medication were used. After discharge from the hospital, the recipients were followed frequently with laboratory tests and examinations.

MAIN RESULTS AND THE ROLE OF CHANCE

The mean costs for preoperative investigations, including IVF, and live donor uterus transplantation with postoperative costs for 2 months, were calculated to be €74 564 (range €50 960-€99 658), from a societal perspective. The four largest components were cost of sick leave (€19 164), cost of postoperative hospitalization (€13 246), surgery cost (€12 779) and costs for preoperative investigations, including IVF (€11 739). Smaller components were costs for anaesthesia (€7207), costs for drugs (€5821), costs for post-surgical tests (€2985) and costs for re-hospitalization (€1623). The costs of the recipient (€42 984) were somewhat higher than the costs of the donor (€31 580), but in terms of costs, they should be viewed as one entity. By using a health care perspective, excluding cost for productivity loss, the total costs would be reduced by 26%.

LIMITATIONS, REASONS FOR CAUTION

A limitation is the restricted sample size and that this is in the experimental, clinical stage of development.

WIDER IMPLICATIONS OF THE FINDINGS

The results provide the first information concerning the costs for pre-transplantation investigations and uterus transplantation procedures with postoperative follow-up. We consider the total estimate to be in the higher interval, because of the extensive research protocol. It is likely that the cost of live donor uterus transplantation will vary between countries and that the costs will be lower in a future clinical setting.

STUDY FUNDING/COMPETING INTEREST(S)

Funding was received from the Jane and Dan Olsson Foundation for Science; the Knut and Alice Wallenberg Foundation; an ALF grant from the Swedish state under an agreement between the government and the county councils; and the Swedish Research Council. None of the authors have a conflict of interest with regard to the study.

TRIAL REGISTRATION NUMBER

NCT01844362.

Uterine Transplantation: Scientific Impact Paper No. 65 April 2021

A uterine transplant, or womb transplant, provides a potential treatment for women who cannot become pregnant or carry a pregnancy because they do not have a womb, or have a womb that is unable to maintain a pregnancy. This is estimated to affect one in 500 women. Options for those who wish to start a family include adoption and surrogacy, but these are associated with legal, cultural, ethical and religious implications that may not be appropriate for some women and their families. A womb transplant is undertaken when the woman is ready to start a family, and is removed following the completion of their family. Womb transplants have been performed all over the world, with more than 70 procedures carried out so far. At least 23 babies have been born as a result, demonstrating that womb transplants can work. While the procedure offers a different option to adoption and surrogacy, it is associated with significant risks, including multiple major surgeries and the need to take medications that help to dampen the immune system to prevent rejection of the womb. To date there has been a 30% risk of a transplant being unsuccessful. Although the number of transplants to date is still relatively small, the number being performed globally is growing, providing an opportunity to learn from the experience gained so far. This paper looks at the issues that have been encountered, which may arise at each step of the process, and proposes a framework for the future. However, long term follow-up of cases will be essential to draw reliable conclusions about any overall benefits of this procedure.

Options for acquiring motherhood in absolute uterine factor infertility; adoption, surrogacy and uterine transplantation

KEY CONTENT

Following the diagnosis of absolute uterine factor infertility (AUFI), women may experience considerable psychological harm as a result of a loss of reproductive function and the realisation of permanent and irreversible infertility.Adoption enables women with AUFI, and their partners, to experience social and legal parenthood, also often providing benefits for the adopted child.Surrogacy offers the opportunity to have genetically related offspring. Outcomes are generally positive in both surrogates and the children born as a result.Uterine transplantation is the only option to restore reproductive anatomy and functionality. While associated with considerable risk, it allows the experience of gestation and the achievement of biological, social and legal parenthood.

LEARNING OBJECTIVES

To gain an understanding of the routes to parenthood available for women with AUFI experiencing involuntary childlessness, such as adoption, surrogacy and, most recently, uterine transplantationTo consider a suggested management plan to facilitate counselling in women with AUFI who experience involuntary childlessness.

ETHICAL ISSUES

In the UK, while the number of children requiring adoption continues to increase, the number being adopted from care is decreasing.Some cultures may hold ethical or religious beliefs that surrogacy is unacceptable, and its legal position in many jurisdictions is problematic.Restrictive selection criteria and high costs may limit future availability of uterine transplantation.

Clinicopathologic Analysis of Uterine Allografts Including Proposed Scoring of Ischemia-reperfusion Injury and T Cell-mediated Rejection-Dallas UtErus Transplant Study: A Pilot Study

BACKGROUND

Uterus transplantation (UTx) enables pregnancy in infertile women. This study describes the histopathological changes of ischemia reperfusion injury and mostly acute T cell-mediated rejection (TCMR) in UTx and proposes modification toward a working formulation grading system with associated treatments.

METHODS

Protocol and indication biopsies from 11 living and 2 deceased donor UTx recipients were analyzed. Serving as a control were 49 age-matched nontransplanted uteri. All posttransplant histopathological specimens were evaluated in a blinded fashion by 3 pathologists. Response to treatment was assessed by follow-up biopsies. Serial serum donor-specific antibody (DSA) responses were also recorded.

RESULTS

Changes attributed to ischemia reperfusion resolved within 2 weeks of UTx in most of the patients. For TCMR grading, perivascular inflammation, focal capillary disruption, and interstitial hemorrhage were added to interface inflammation, intercellular edema, stromal inflammation, and epithelial apoptotic bodies. Of the 173 protocol biopsies, 98 were classified as negative for TCMR; 34, indeterminate-borderline; 35, mild; 3, moderate; and 3, severe, 1 of which occurred in a DSA-positive recipient and also showed microvascular injury. Corticosteroids successfully treated all moderate to severe TCMR episodes. Mild TCMR was treated by increasing existing baseline immunosuppression. Indeterminate-borderline episodes were not treated. Neither ischemia reperfusion injury nor TCMR with DSA adversely affected embryo transfer.

CONCLUSION

Relying on a modified histopathological grading system, we developed a treatment strategy resulting in resolution of TCMR and successful pregnancies.

Uterine Transplantation: Evolving Data, Success, and Clinical Importance

Uterine transplantation is an evolving procedure to allow for childbearing in paitents with absolute uterine factor infertility. The objective of this study was to review the existing literature using a comprehensive PubMed literature search. A systematic medical subheadings search strategy was used with the terms "uterus transplant" and "uterine transplantation". Of the 75 full-text articles assessed for eligibility, 68 were included in the qualitative synthesis. Of these, 9 were included in the meta-analysis on living donor uterine transplant, 5 on deceased donor uterine transplant, and 6 case reports of single uterine transplants. In conclusion, uterus transplant is a nascent field undergoing a rapid rate of evolution as programs mature their data and increase the number of procedures performed. The most recent publications and advances are thus summarized in this article to capture the most up-to-date information.

First Successful Delivery after Uterus Transplantation in MHC-Defined Cynomolgus Macaques

Delivery following uterus transplantation (UTx)—an approach for treating uterine factor infertility—has not been reported in nonhuman primate models. Here, six female major histocompatibility complex (MHC)-defined cynomolgus macaques that underwent allogeneic UTx were evaluated. Antithymocyte globulin and rituximab were administered to induce immunosuppression and a triple maintenance regimen was used. Menstruation resumed in all animals with long-term survival, except one, which was euthanized due to infusion associated adverse reaction to antithymocyte globulin. Donor-specific antibodies (DSA) were detected in cases 2, 4, and 5, while humoral rejection occurred in cases 4 and 5. Post-transplant lymphoproliferative disorder (PTLD) developed in cases 2 and 3. Pregnancy was attempted in cases 1, 2, and 3 but was achieved only in case 2, which had haploidentical donor and recipient MHCs. Pregnancy was achieved in case 2 after recovery from graft rejection coincident with DSA and PTLD. A cesarean section was performed at full-term. This is the first report of a successful livebirth following allogeneic UTx in nonhuman primates, although the delivery was achieved via UTx between a pair carrying haploidentical MHCs. Experimental data from nonhuman primates may provide important scientific knowledge needed to resolve unsolved clinical issues in UTx.

Custodiol-N Is Superior to Custodiol® Solution in Experimental Rat Uterus Preservation

Uterus transplantation (UTx) is the first and only available treatment for women with absolute uterine factor infertility. However, clinical application is limited by the lack of organs, ischemia/reperfusion injury, as well as immunosuppression after UTx. Several different preservation solutions are used in experimental and clinical UTx, including Custodiol^® solution. Recently, the novel Custodiol-N solution was developed with superior results in organ preservation. However, the solution was not tested yet in UTx. Therefore, the aims of this study were to evaluate the effect of Custodiol-N in uterus prolonged cold preservation time (8 and 24 h), compared to Custodiol^® solution. Uterus tissue samples were obtained from adult Sprague Dawley rats (n = 10/group). Cold ischemic injury was estimated by histology, including immunohistochemistry, and biochemical tissue analyses. After 8 h of cold ischemia, higher percentage of tissue edema, necrosis signs and myeloperoxidase expression, as well as lower superoxide dismutase activity were found in Custodiol^® compared to Custodiol-N (p < 0.05). These differences were more pronounced after 24 h of cold preservation time (p < 0.05). This study demonstrated that Custodiol-N protects uterus grafts from cold ischemic injury better than standard Custodiol^® most likely via inhibition of oxidative stress and tissue edema. It seems that iron chelators in the composition of Custodiol-N play an important protective role against cold ischemia.

First live birth after uterus transplantation in the Middle East

Background

The first live birth after uterus transplantation took place in Sweden in 2014. It was the first ever cure for absolute uterine factor infertility. We report the surgery, assisted reproduction, and pregnancy behind the first live birth after uterus transplantation in the Middle East, North Africa, and Turkey (MENAT) region.

A 24-year old woman with congenital absence of the uterus underwent transplantation of the uterus donated by her 50-year-old multiparous mother. In vitro fertilization was performed to cryopreserve embryos. Both graft retrieval and transplantation were performed by laparotomy. Donor surgery included isolation of the uterus, together with major uterine arteries and veins on segments of the internal iliac vessels bilaterally, the round ligaments, and the sacrouterine ligaments, as well as with bladder peritoneum. Recipient surgery included preparation of the vaginal vault, end-to-side anastomosis to the external iliac arteries and veins on each side, and then fixation of the uterus.

Results

One in vitro fertilization cycle prior to transplantation resulted in 11 cryopreserved embryos. Surgical time of the donor was 608 min, and blood loss was 900 mL. Cold ischemia time was 85 min. Recipient surgical time was 363 min, and blood loss was 700 mL. Anastomosis time was 105 min. Hospital stay was 7 days for both patients. Ten months after the transplantation, one previously cryopreserved blastocyst was transferred which resulted in viable pregnancy, which proceeded normally (except for one episode of minor vaginal bleeding in the 1st trimester) until cesarean section at 35 + 1 weeks due to premature contractions and shortened cervix. A healthy girl (Apgar 9-10-10) weighing 2620 g was born in January 2020, and her development has been normal during the first 6 months.

Conclusions

This is the first report of a healthy live birth after uterus transplantation in the MENAT region. We hope that this will motivate further progress and additional clinical trials in this area in the Middle East Region, where the first uterus transplantation attempt ever, however unsuccessful, was performed already three decades ago.

Experimental techniques for the development of a uterus transplantation model in cynomolgus macaques

Uterus transplantation (UTx) is now a treatment for women with uterine factor infertility to have a child. However, UTx is still largely at the experimental stage, and many medical issues remain unsolved. Therefore, adequate studies in large animals including non-human primates are required for validation of these issues. UTx research, especially in non-human primates, can provide important information for its full establishment in humans due to the anatomical and physiological similarities between the two. We accumulated data from UTx studies using cynomolgus macaques since 2009 and established autologous and allogeneic UTx models which led to deliveries after performing the procedure. In this paper, we summarized key points to develop UTx models in cynomolgus macaques based on our experience. UTx models in non-human primates can surely contribute new and beneficial knowledge in this field and can be useful for the further development of UTx in humans.

Immunosuppression in uterine transplantation

Uterine transplantation (UTx) is the only effective treatment for uterine infertility patients to become genetic mothers. After decades of research, the surgical methods of UTx are very developed. There are numerous factors that affect the results of UTx, such as selection of the donor uterus before transplantation, immunosuppressive therapy post-transplantation, rejection monitoring, and immune tolerance. Studies have shown that immune rejection is a crucial factor affecting the survival rate after organ transplantation. Unlike liver or kidney transplantation, the aim of UTx is to obtain a functional uterus that is able to support successful pregnancy and birth of a healthy fetus. Because of the unique purpose of UTx, its immunosuppressive program is relatively specialized. Some immunosuppressive agents can cause perinatal complications, and inducing immune tolerance is necessary to resolve these side effects. Further understanding of the immune mechanism of UTx and the continuous development of new immunosuppressive agents, combined with the application of assisted reproductive technology, will be more conducive to the realization of UTx to breed offspring.

Human uterine vasculature with respect to uterus transplantation: A comprehensive review

Due to the novelty of uterus transplantation, data on preferable inflow and outflow of the graft are limited. This paper reviews the technique, type of vessels and the outcome. A systematic search of the PubMed database was conducted. We extracted and analyzed data on the arteries and veins utilized, types of anastomosis, types of donors, complications and the outcome. Thirty eight sources reported 51 human uterine transplantations, 10 graft thromboses and 25 live births. Inflow was established with two uterine arteries (UA) with/without the anterior division of the internal iliac artery in 62% (n = 31) of cases, two UA arteries with a segment/patch of the internal iliac artery in 34% (n = 17) of cases or two UA with a conduit in 4% of cases (n = 2). Both cases with a conduit developed thrombosis (n = 2). Arterial thrombosis/ischemia developed in 8 of the 51 cases. In 50% of cases with arterial thrombosis, atherosclerosis was identified as a possible cause. Outflow was established by two internal iliac veins with patches/segments in 27.5% of cases (n = 14) followed by two utero-ovarian veins in 25.5% (n = 13). Venous thrombosis occurred in 3 of the 51 cases. Uterine arteries with/without anterior division of the internal iliac artery were the most frequent arteries used for inflow and produced the highest patency rate. The presence of atherosclerosis and complex arterial reconstruction was associated with a high rate of arterial thrombosis. None of the veins utilized in the procedures appeared to be superior. There are insufficient data to draw a definite conclusion.

Live birth after cervical ectopic uterus transplantation in mice

An ideal animal model is a prerequisite for the basic research of uterus transplantation. This study aimed to develop a new cervical ectopic uterus transplantation mice model, which was established by vascular anastomosis of the right common iliac artery and vein of the donor with the right common carotid artery and external jugular vein of the recipient, respectively, using the cuff method. The survival status of the transplanted uterus was assessed by macroscopic observation and histological examination after surgery, and the function of the graft uterus was tested by verifying whether the pregnancy is possible. A total of 40 transplants were performed, of which only 1 failed due to donor hemorrhage. After 26 transplants, the total operation time reduced to 52.4 ± 3.8 minutes, of which the total ischemia time took 6.6 ± 1.1 minutes. Sixty days after transplantation, all the graft uteri had a good blood supply and spontaneous contraction. The histology showed no significant difference between the transplanted uterus and the native. Embryo transfer experiments have proven that the transplanted uterus has uterine function. In conclusion, this new model is an effective and simple mice model for the studies of the scientific issues related to uterus transplantation.

Metabolic alterations of uterine grafts after extended cold ischemic storage: experimental study in ewes

Uterine transplantation from a deceased donor could become an available option for widely treating uterine infertility. However, this procedure requires more precise knowledge about the graft's tolerance to extended cold ischemia. Here, we sought to assess the uterine metabolic alterations after extended cold ischemic storage in a model of auto-transplantation in ewe. A total of 14 uterine auto-transplantations were performed, divided into 2 groups: 7 after 3 h of cold ischemia time (CIT) and 7 after 24 h. Venous uterine blood was collected before uterus retrieval and during reperfusion (30, 60 and 90 min); thereafter, blood gases, lactate, glucose and amino acids (AAs) were analyzed. Apoptosis analyses were performed before uterus retrieval and following reperfusion in uterus biopsies. A total of 12 uterine auto-transplantations were successfully performed and 7 ewes were alive ≥8 days after transplantation. After reperfusion, a decrease in pH, a rise of lactate and lactate/glucose ratio and a delayed decrease of pO2 were found in the 3 h CIT group. No significant variation of these parameters was observed in the 24 h CIT group. Significant decreases of AAs were observed during reperfusion and these decreases were more pronounced and concerned a larger number of compounds in the 24 h CIT group than in the 3 h CIT group. There was no significant uterine apoptotic signal in either group. Overall, these results suggest that extended CIT storage delayed restoration of aerobic glycolysis and induced an increase in AA requirements of the uterus after reperfusion. However, this biochemical alteration did not reduce success rate for uterine transplantation.

Endometrial autotransplantation in rabbits: Potential for fertility restoration in severe Asherman's syndrome

OBJECTIVE

Uterine transplantation is now considered a feasible treatment for women with absolute uterine factor infertility and has been successfully performed for a woman with Asherman's syndrome (AS). The endometrium is a clinically and histologically distinct entity from the surrounding myometrium. Endometrial transplantation (ETx) may offer a less invasive option, with less immunogenic impact, to restore fertility in women with severe AS. The objective of this study was to assess the feasibility of ETx by evaluating surgical and reproductive outcomes following endometrial autotransplantation in a rabbit model.

STUDY DESIGN

A longitudinal study assessing surgical, biochemical, radiological, reproductive and histological outcomes following endometrial autotransplantation in ten New Zealand white rabbits.

RESULTS

Ten procedures were performed, including 8 endometrial auto-transplants (ETx) and 2 endometrial resections (ER), to control against endometrial regeneration. Eight procedures were successful, whereas two rabbits from the ETx group died intra-operatively. Three rabbits were euthanised at 48, 72 and 96 h post-operatively to assess gross and histological appearances. Two rabbits, one from the ETx group and one from the ER group, died four weeks and eight weeks post-operatively. Three rabbits subsequently underwent two cycles of in-vitro fertilization. The first cycle resulted in an implantation rate of 57% in the un-operated uteri. In two rabbits who underwent ETx, an implantation rate of 28.6% was seen. In the second cycle, an implantation rate of 61.9 % (13 implantations) was observed in the control uteri. In the two ETx females, an implantation rate of 14.3 % was seen. No pregnancies were seen in either cycle in the animals who underwent ER. Despite successful implantations in both cycles in the ETx rabbits, no livebirths were achieved. Following death or euthanasia there was gross and microscopic evidence of viable endometrium following ETx, but not following ER.

CONCLUSION

This study has revealed, for the first time, the feasibility of ETx with gross and microscopic evidence of viable endometrium, and the demonstration of clinical pregnancies. Whilst further studies are essential, and the achievement of successful livebirths fundamental, ETx may offer a potential fertility restoring opportunity for women with severe, treatment refractory cases of AS.

Uterus transplantation: transition from experimental to clinical procedure

Uterus transplantation is a novel treatment to treat uterine factor infertility. This type of infertility is due to absence of an anatomical or functional uterus. This review covers important research findings in the field, and this research formed the base for introduction of uterus transplantation as an experimental clinical procedure. The basic animal-research investigated central facets such as surgery, immunosuppression, ischemia-reperfusion injury, rejection, and fertility. The first clinical uterus transplantation trial was started in 2013 and this was a live donor trial. The first live birth was reported in 2014 and this has been followed by a number of births from the initial trial in Sweden and in several other parts of the world. The uterus transplantations procedures and the live births that have been scientifically reported will be discussed in this review. Lastly, some aspects for an efficient transition from an experimental phase into a clinical phase of uterus transplantation will be discussed.

Uterus Transplantation as a Therapy Method in Mayer-Rokitansky-Küster-Hauser Syndrome

The Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is the most common cause of uterine aplasia (underdevelopment or absence) at a frequency estimated to be worldwide of 1/4500 births of new-born female infants.

This is a literature review aiming to determine the sufficiency of the uterine transplantation (UTx) method as a therapeutic protocol for the MRKH syndrome.

Online searches were carried out in PubMed, Embase, CINAHL and Google scholar databases, during January and February 2019. The search included a combination of the various terms (see key words) as well as a combination of these terms in Greek and English so as to identify and display articles that would be as close as possible to the subject of research.

The online search yielded 95 articles. Eighty-five of these were considered as eligible and possible sources from the title and abstract presented but later were excluded, whereas 10 of them were selected to be included in the literature review. The literature review results showed that two therapeutic methods that are now successfully applied are the Vecchietti method and the Davydov method, which is the latest and less invasive technique but with equally if not improved immediate results. However, this treatment is not adequate to satisfy or provide a solution for the reproduction requirements of this patient group. The UTx proved sufficient.

Although uterus transplant could be considered the ideal solution for the management of infertility and the satisfaction of the reproductive and sexual needs of women with MRKH syndrome, since the first successful pregnancy after uterine transplantation is a reality in the recent years, it is early days to be considered as a safe mode of management.

Long-Term Outcome and Rejection After Allogeneic Uterus Transplantation in Cynomolgus Macaques

Uterus transplantation (UTx) is an option for women with uterine factor infertility to have a child, but is still in the experimental stage. Therefore, allogeneic animal models of UTx are required for resolution of clinical issues. In this study, long-term outcomes were evaluated in four recipients (cases 1-4) after allogeneic UTx in cynomolgus macaques. Immunosuppression with antithymocyte globulin induction and a triple maintenance regimen was used. Postoperative ultrasonography and biopsy of the transplanted uterus and immunoserological examinations were performed. All four recipients survived for >3 months after surgery, but continuous menstruation did not resume, although temporary menstruation occurred (cases 1 and 2). All animals were euthanized due to irreversible rejection and no uterine blood flow (cases 1, 2 and 4) and post-transplant lymphoproliferative disorder (case 3). Donor-specific antibodies against MHC class I and II were detected in cases 1, 2 and 4, but not in case 3. Peripheral lymphocyte counts tended to elevate for CD3⁺, CD20⁺ and NK cells in conjunction with uterine rejection, and all animals had elevated stimulation indexes of mixed lymphocyte reaction after surgery. Establishment of allogeneic UTx in cynomolgus macaque requires further exploration of immunosuppression, but the clinicopathological features of uterine rejection are useful for development of human UTx.

Human uterine transplantation: a review of outcomes from the first 45 cases

Uterine transplantation restores reproductive anatomy in women with absolute uterine factor infertility and allows the opportunity to conceive, experience gestation, and acquire motherhood. The number of cases being performed is increasing exponentially, with detailed outcomes from 45 cases, including nine live births, now available. In light of the data presented herein, including detailed surgical, immunosuppressive and obstetric outcomes, the feasibility of uterine transplantation is now difficult to refute. However, it is associated with significant risk with more than one-quarter of grafts removed because of complications, and one in ten donors suffering complications requiring surgical repair. TWEETABLE ABSTRACT: Uterine transplantation is feasible in women with uterine factor infertility, but is associated with significant risk of complication.

The vaginal microbiome in uterine transplantation

Women with congenital absolute uterine factor infertility (AUFI) often need vaginal restoration to optimise sexual function. Given their lack of procreative ability, little consideration has previously been given to the resultant vaginal microbiome (VM). Uterine transplantation (UTx) now offers the opportunity to restore these women's reproductive potential. The structure of the VM is associated with clinical and reproductive implications that are intricately intertwined with the process of UTx. Consideration of how vaginal restoration methods impact VM is now warranted and assessment of the VM in future UTx procedures is essential to understand the interrelation of the VM and clinical and reproductive outcomes. TWEETABLE ABSTRACT: The vaginal microbiome has numerous implications for clinical and reproductive outcomes in the context of uterine transplantation.

Uterine Transplant: A Risk to Life or a Chance for Life?

Being inherently different from any other lifesaving organ transplant, uterine transplantation does not aim at saving lives but supporting the possibility to generate life. Unlike the kidneys or the liver, the uterus is not specifically a vital organ. Given the non-lifesaving nature of this procedure, questions have been raised about its feasibility. The ethical dilemma revolves around whether it is worth placing two lives at risk related to surgery and immunosuppression, amongst others, to enable a woman with absolute uterine factor infertility to experience the presence of an organ enabling childbirth. In the year 2000, the first uterine transplantation, albeit unsuccessful, was performed in Saudi Arabia from where it has spread to the rest of the world including Sweden, the United States and now recently India. The procedure is, however, still in the preclinical stages and several ethical, legal, social and religious concerns are yet to be addressed before it can be integrated into the clinical setting as standard of care for women with absolute uterine factor infertility.

Uterus Allo-Transplantation in a Swine Model: Long-Term Graft Survival and Reproductive Function

Background

The present study examined the feasibility and safety of allogeneic uterus transplantation (UTx) from a living donor and assessed long-term graft survival and the resumption of reproductive function in a swine model.

Material/Methods

Ten female miniature swine with regular menstrual cycles were used; the animals were either donors or recipients (n=5) depending on the sibling. Retrieval surgery included uterus and uterine arteries together with the anterior branches of the internal iliacs from the living donor; the vaginal canal was cut. After the back-table had been prepared, bilateral internal iliac arteries were anastomosed end-to-side with the external iliac arteries. The transplanted uterus was evaluated based on the arterial blood flow by transabdominal ultrasonography and observed by secondary laparotomy after surgery; estrus recovery was stimulated by mating with a male, and artificial embryo transfer was performed in healing swine.

Results

All 5 pigs revealed successful surgery without any surgical complications, injuries to other organs, or unanticipated vascular injury. All recipients survived for >3 months after the surgery, except pig 5, which died due to uterus necrosis 3 days post-surgery. A 100% surgical success rate and 80% long-term survival rate of the receptor were observed. Pig 2 had temporary estrus resumed, and the artificial embryo was transplanted 3 months after surgery; however, apparent gestation was not found by ultrasonography.

Conclusions

This study evaluated the safety and feasibility of the technology of allogeneic UTx, which was performed only by transplant uterine artery system from living-donor surgery in a swine model. Laboratory animals can show long-term survival and resumed estrous after UTx, which can be monitored by ultrasonography to assess the arterial blood flow of the grafted uterus.

Basic research on uterus transplantation in nonhuman primates in Japan

Uterus transplantation (UTx) is now a potential option for women with uterine factor infertility to have a child. However, UTx is still in an experimental stage and basic animal studies including in nonhuman primates are needed for accumulation of data that will provide important information for establishment of UTx in humans. Herein, we summarized our experiences using cynomolgus macaques, with the goal of promoting further development of UTx studies in nonhuman primates. Our basic studies using cynomolgus macaques were summarized, including the results of other teams in nonhuman primates. Our team in Japan launched UTx research in 2009 using cynomolgus macaques and has accumulated a large archive of results in the UTx research field, including examination of uterine blood flow, surgical procedures of autologous and allogeneic UTx, organ perfusion methods in deceased donor models, immunological response and rejection and ischemia/reperfusion injury. We achieved the first delivery after autologous UTx in primates and the first periodic recovery of menstruation after allogeneic UTx in nonhuman primate models. Results from animal studies, including those in nonhuman primates, provide the basis for clinical application of UTx. Therefore, our accumulated data since 2009 and our basic experience in cynomolgus macaque are meaningful for future UTx trials in Japan. In addition, more validation in nonhuman primate models is needed for resolution of medical issues and further development of UTx in humans, despite clinical application of UTx in several countries.

Allogeneic ovarian transplantation using immunomodulator preimplantation factor (PIF) as monotherapy restored ovarian function in olive baboon

PURPOSE

Allogeneic ovarian transplantation may be an alternative in the future to oocyte donation in women with premature ovarian failure. The objectives of this study were to (a) evaluate allotransplantation feasibility for restoration of ovarian function and (b) assess efficacy of synthetic preimplantation factor (PIF) monotherapy as sole immune-acceptance regimen.

METHODS

This is an experimental animal study using non-human primates (Papio anubis). Allogeneic orthotopic ovarian tissue transplantation was performed in two female olive baboons. PIF was administered as a monotherapy to prevent immune rejection and achieve transplant maintenance and function. Subjects underwent bilateral oophorectomy followed by cross-transplantation of prepared ovarian cortex. Postoperatively, subjects were monitored for clinical and biochemical signs of graft rejection and return of function. Weekly blood samples were obtained to monitor graft acceptance and endocrine function restoration.

RESULTS

Postoperatively, there were no clinical signs of rejection. Laboratory parameters (alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), creatinine) did not indicate organ rejection at any stage of the experiment. Initially, significant loss of follicles was noticed after grafting and serum follicle-stimulating hormone (FSH) and E2 levels were consistent with ovarian failure. Seven months after transplantation, one animal exhibited recurrence of ovarian endocrine function (perineal swelling, E2 rise, FSH decrease, and return of menstruation).

CONCLUSIONS

Organ rejection after allogeneic ovarian transplantation was prevented using PIF as monotherapy for the first time and no side effects were recorded. The study suggests the clinical feasibility of ovarian allotransplantation to obtain ovarian function.

Uterus transplantation: From animal models through the first heart beating pregnancy to the first human live birth

Absolute uterine factor infertility affects 3-5% of the general population, and unfortunately this condition is untreatable. There are some available options, including surrogacy or adoption, but neither of these suits each and every woman who desires to have her own genetic child. With recent advances in surgery and transplant immunology, uterus transplantation may be a source of hope for these women with uterine infertility. In the last decade, a number of animal species including rats, mice, rabbits, pigs, sheep, and primates have been used as experimental models, and pregnancies were achieved in some of these. Human data consist of 11 subjects yielding positive pregnancy results with no live births in the second trial from Turkey and, more fortunately, live births from the latest trial from Sweden. In the light of all these studies, uterus transplantation has been proven to be a viable option for women with uterine factor infertility.

Uterus transplantation: Toward clinical application in Japan

Background

In recent years, uterus transplantation (UTx) has been applied as the treatment for patients with uterine factor infertility worldwide. Thus, the clinical application of UTx in Japan should be considered through both the history of UTx technology development in the world and future prospects.

Methods

Recent information on UTx was collected via a literature survey and the Internet.

Results

Basic research using various animals has been done mainly since 2000. In 2014, the world's first UTx baby was born in Sweden. In total, 24 UTx procedures have been performed at 10 institutes in nine countries and five births were obtained (as of May, 2017). In Japan, the "Project Team for Uterus Transplantation" initiated UTx experiments in 2008 and the "Japan Society for Uterus Transplantation" was organized in March, 2014. In the rest of the world, the "International Society for Uterus Transplantation" was established in January, 2016.

Conclusion

Uterus transplantation is still under development as a reproductive medicine tool and organ transplant procedure. A collaborative system that is not limited by facilities and specialties should strive to build an "all-Japan" team.

Modified human uterus transplantation using ovarian veins for venous drainage: the first report of surgically successful robotic-assisted uterus procurement and follow-up for 12 months

OBJECTIVE

To report the 12-month results of the first human uterus transplantation case using robot-assisted uterine retrieval. This type of transplantation may become a treatment for permanent uterine factor infertility.

DESIGN

Case study.

SETTING

University hospital.

PATIENT(S)

A 22-year-old woman with complete müllerian agenesis who underwent a previous surgery for vaginal reconstruction. The live uterine donor was her mother.

INTERVENTION(S)

The uterus transplantation procedure consisted of robot-assisted uterine procurement, orthotopic replacement and fixation of the retrieved uterus, revascularization, and end-to-side anastomoses of bilateral hypogastric arteries and ovarian-uterine vein to the bilateral external iliac arteries and veins.

MAIN OUTCOME MEASURE(S)

Data from preoperative investigations, surgery, and follow-up (12 months).

RESULT(S)

The duration of the donor and recipient surgeries were 6 and 8 hours, 50 minutes, respectively. No immediate perioperative complications occurred in the recipient or donor. The recipient experienced menarche 40 days after transplant surgery, and she has had 12 menstrual cycles since the surgery. No rejection episodes occurred in the recipient.

CONCLUSION(S)

These results demonstrate the feasibility of live-donor uterine transplantation with a low-dose immunosuppressive protocol and the role of DaVinci robotic assistance during human uterine procurement.

CLINICAL TRIAL REGISTRATION NUMBER

XJZT12Z06.

Womb transplants with live births: an update and the future

INTRODUCTION

Absolute uterine factor infertility, with a uterine absence or presence of a nonfunctional uterus, has during the last decades been the only remaining, major group of female infertility. Uterus transplantation (UTx) has now emerged as the first therapy for these women that have traditionally been regarded as unconditionally infertile. Areas covered: This review summarizes the research preparations in several experimental animal species that paved the way for the clinical introduction of UTx. The article also describes the human UTx attempts that have been reported up until today and the several live births that have occurred after the initial UTx baby was born in 2014. Future developments in human UTx and efforts to create a bioengineered uterus are also discussed. Expert opinion: UTx has already at this early phase of experimental introduction in the human setting proved to be a highly effective treatment for absolute uterine factor infertility. The UTx procedure has now been introduced at several centers worldwide within clinical research studies and with variations in techniques. The outcome and data from these studies will further optimize the UTx procedure to become a safe and highly effective infertility treatment.

Monitoring of Human Uterus Transplantation With Cervical Biopsies: A Provisional Scoring System for Rejection

Until now, absolute uterine factor infertility has been the major untreatable form of female infertility. Uterus transplantation has recently proven to be the first successful treatment for absolute uterine factor infertility, with demonstration of live births. In this study, live donation uterus transplantation was performed in nine women. In total, 163 cervical biopsies (149 protocol, 14 follow-up) were taken to detect histopathological signs of rejection. Based on experience from animal experiments, we used a three-grade scoring system to evaluate biopsies systematically. Nine episodes of rejection were diagnosed in five patients: grade 1 in six episodes, grade 2 in two episodes, and grade 3 in one episode. Treatment decisions were based on histopathology, and all rejection episodes were reversed after treatment. The biopsies were reviewed retrospectively, and immunohistochemistry was performed to characterize the inflammatory infiltrates. A borderline category was introduced to avoid overtreatment of patients. Based on our review of all biopsies, we put forward a simple grading system for monitoring of rejection and to guide immunosuppressive treatment in uterus transplantation.

Bioengineering Strategies to Treat Female Infertility

Bioengineering strategies have demonstrated enormous potential to treat female infertility as a result of chemotherapy, uterine injuries, fallopian tube occlusion, massive intrauterine adhesions, congenital uterine malformations, and hysterectomy. These strategies can be classified into two broad categories as follows: (i) Transplantation of fresh or cryopreserved organs into the host and (ii) tissue engineering approaches that utilize a combination of cells, growth factors, and biomaterials that leverages the body's inherent ability to regenerate/repair reproductive organs. While whole organ transplant has demonstrated success, the source of the organ and the immunogenic effects of allografts remain challenging. Even though tissue engineering strategies can avoid these issues, their feasibilities of creating whole organ constructs are yet to be demonstrated. In this article we summarize the recent advancements in the applications of bioengineering to treat female infertility.

The history behind successful uterine transplantation in humans

This paper aimed to describe the basic aspects of uterine transplant (UTx) research in humans, including preliminary experiences in rodents and domestic species. Studies in rats, domestic species, and non-human primates validated and optimized the UTx procedure in terms of its surgical aspects, immunosuppression, rejection diagnosis, peculiarities of pregnancy in immunosuppressed patients, and patients with special uterine conditions. In animal species, the first live birth from UTx was achieved in a syngeneic mouse model in 2003. Twenty-five UTx procedures have been performed in humans. The first two cases were unsuccessful, but established the need for rigorous research to improve success rates. As a result of a controlled clinical study under a strictly designed research protocol, nine subsequent UTx procedures have resulted in six healthy live births, the first of them in 2014. Further failed UTx procedures have been performed in China, Czech Republic, Brazil, Germany, and the United States, most of which using living donors. Albeit still an experimental procedure in, UTx is the first potential alternative for the treatment of absolute uterine factor infertility (AUFI).

Uterus transplantation and beyond

Uterus transplantation is today the only available treatment for absolute uterine factor infertility which is caused by either congenital/surgical uterine absence or that a present uterus is non-functioning. Structured animal-based research, from rodents to nonhuman primates, was the scientific basis for a successful introduction of uterus transplantation as a clinical procedure. The patient groups for uterus transplantation, the preclinical research and data from the published human cases will be covered herein. During recent years the concept of bioengineering of organs and tissues has emerged. Creation of a bioengineered uterus is in the initial research state, with experiments performed in rodents. The research that has been performed to create a bioengineered uterus will be summarized. In conclusion, uterus transplantation is now a clinical experimental procedure for treatment of uterine factor infertility. In parallel to the establishment of this combined assisted reproduction technique and transplantation procedure as a routine clinical procedure, we predict that uterus bioengineering will develop further towards introduction within the human setting, but that this process will take several years.

Sheep Model for Uterine Transplantation: The Best Option Before Starting a Human Program

OBJECTIVE:

This study reports the first four cases of a uterine transplant procedure conducted in sheep in Latin America. The aim of this study was to evaluate the success of uterine transplantation in sheep.

METHOD:

The study was conducted at Laboratory of Medical Investigation 37 (LIM 37) at the University of São Paulo School of Medicine. Four healthy mature ewes weighing 40-60 kg were used as both the donor and recipient for a transplant within the same animal (auto-transplant). Institutional guidelines for the care of experimental animals were followed.

RESULTS:

The first two cases of auto-transplant were performed to standardize the technique. After complete uterine mobilization and isolation of the blood supply, the unilateral vascular pedicle was sectioned and anastomosed on the external iliac vessels. After standardization, the protocol was implemented. Procurement surgery was performed without complications or bleeding. After isolation of uterine arteries and veins as well as full mobilization of the uterus, ligation of the distal portion of the internal iliac vessels was performed with subsequent division and end-to-side anastomosis of the external iliac vessels. After vaginal anastomosis, the final case presented with arterial thrombosis in the left uterine artery. The left uterine artery anastomosis was re-opened and flushed with saline solution to remove the clot from the artery lumen. Anastomosis was repeated with restoration of blood flow for a few minutes before another uterine artery thrombosis appeared on the same side. All four animals were alive after the surgical procedure and were euthanized after the experimental period.

CONCLUSION:

We describe the success of four uterine auto-transplants in sheep models.

Uterus Transplantation: Current State and Future Perspectives

Absolute uterine factor infertility (AUFI) has traditionally been regarded as untreatable. Gestational surrogacy (GS) is not permitted in most countries and societies in the world due to ethical, religious or legal reasons. The interest in uterus transplantation (UTx) as a treatment for AUFI started in the 1960s and, after some disappointing results, raised again in the new century, when our and other groups obtained live off-spring after UTx in the mouse, and here we review extensively the results of animal research. In September 2014, the first baby was born after human UTx and this proof-of-concept of UTx as an infertility treatment has been followed by several more births. All cases described in the literature are also reviewed.

The overall evidence suggests that the clinical introduction of UTx as the first available treatment for AUFI has been successful. However, UTx will stay at experimental stage for several years whilst optimizing the procedure and ensuring its safety from a medical and psychological perspective.