Current status of uterus transplantation in primates and issues for clinical application

Multilayered Shape-Morphing Scaffolds with a Hierarchical Structure for Uterine Tissue Regeneration

Owing to dysfunction of the uterus, millions of couples around the world suffer from infertility. Different from conventional treatments, tissue engineering provides a new and promising approach to deal with difficult problems such as human tissue or organ failure. Adopting scaffold-based tissue engineering, three-dimensional (3D) porous scaffolds in combination with stem cells and appropriate biomolecules may be constructed for uterine tissue regeneration. In this study, a hierarchical tissue engineering scaffold, which mimicked the uterine tissue structure and functions, was designed, and the biomimicking scaffolds were then successfully fabricated using solvent casting, layer-by-layer assembly, and 3D bioprinting techniques. For the multilayered, hierarchical structured scaffolds, poly(l-lactide-co-trimethylene carbonate) (PLLA-co-TMC, "PLATMC" in short) and poly(lactic acid-co-glycolic acid) (PLGA) blends were first used to fabricate the shape-morphing layer of the scaffolds, which was to mimic the function of myometrium in uterine tissue. The PLATMC/PLGA polymer blend scaffolds were highly stretchable. Subsequently, after etching of the PLATMC/PLGA surface and employing estradiol (E2), polydopamine (PDA), and hyaluronic acid (HA), PDA@E2/HA multilayer films were formed on PLATMC/PLGA scaffolds to build an intelligent delivery platform to enable controlled and sustained release of E2. The PDA@E2/HA multilayer films also improved the biological performance of the scaffold. Finally, a layer of bone marrow-derived mesenchymal stem cell (BMSC)-laden hydrogel [which was a blend of gelatin methacryloyl (GelMA) and gelatin (Gel)] was 3D printed on the PDA@E2/HA multilayer films of the scaffold, thereby completing the construction of the hierarchical scaffold. BMSCs in the GelMA/Gel hydrogel layer exhibited excellent cell viability and could spread and be released eventually upon biodegradation of the GelMA/Gel hydrogel. It was shown that the hierarchically structured scaffolds could evolve from the initial flat shape into the tubular structure completely in an aqueous environment at 37 °C, fulfilling the requirement for curved scaffolds for uterine tissue engineering. The biomimicking scaffolds with a hierarchical structure and curved shape, high stretchability, and controlled and sustained E2 release appear to be very promising for uterine tissue regeneration.

The artificial uterus: on the way to ectogenesis

The inability to support the growth and development of a mature fetus up to delivery results in significant human suffering. Current available solutions include adoption, surrogacy, and uterus transplantation. However, these options are subject to several ethical, religious, economic, social, and medical concerns. Ectogenesis is the process in which an embryo develops in an artificial uterus from implantation through to the delivery of a live infant. This current narrative review summarizes the state of recent research focused on human ectogenesis. First, a literature search was performed to identify published reports of previous experiments and devices used for embryo implantation in an extracorporeally perfused human uterus. Furthermore, studies fitting that aim were selected and critically evaluated. Results were synthesized, interpreted, and used to design a prospective strategy for future research. Therefore, this study suggests that full ectogenesis might be obtained using a computer-controlled system with extracorporeal blood perfusion provided by a digitally controlled heart-lung-kidney system. From a clinical perspective, patients who will derive significant benefits from this technology are mainly those women diagnosed with anatomical abnormalities of the uterus and those who have undergone previous hysterectomies, numerous abortions, and experienced premature birth. Ectogenesis is the complete development of an embryo in an artificial uterus. It represents the solutions for millions of women suffering from premature deliveries, and the inability to supply growth and development of embryos/fetuses in the womb. In the future, ectogenesis might replace uterine transplantation and surrogacy.

Graft Failure after Uterus Transplantation in 16 Recipients: A Review

Uterus transplantation (UTx) is now an alternative to surrogacy and adoption for women with uterine factor infertility to have children; however, there are still unresolved clinical and technical issues. One of these is that the graft failure rate after transplantation is somewhat higher than that of other life-saving organ transplants, which is a critical concern. Herein, we summarize the details of 16 graft failures after UTx with living or deceased donors using the published literature in order to learn from these negative outcomes. To date, the main causes of graft failure are vascular factors (arterial and/or venous thrombosis, atherosclerosis, and poor perfusion). Many recipients with thrombosis develop graft failure within one month of surgery. Therefore, it is necessary to devise a safe and stable surgical technique with higher success rates for further development in the UTx field.

Keio Uterus Transplantation Research: From Basic Research toward Future Clinical Application

Uterus transplantation (UTx) is now a potential option to allow women with uterine factor infertility to give birth. However, UTx is still at an experimental stage, and basic animal studies, including in non-human primates, are needed for the accumulation of data prior to clinical application. Considering that UTx may provide new hope to Japanese women, we launched UTx research in 2009 and have since accumulated a large archive of results in the UTx research field. Furthermore, we have carried out various activities aimed at the implementation of clinical applications of UTx in Japan while clarifying the ethical and social issues involved. Currently, the clinical application of UTx in Japan is just around the corner, and it is expected that UTx research will develop further in the future. Herein, we summarize our basic experiences using non-human primates and our activities with the goal of future clinical applications.

Concerns Associated with Uterus Transplantation in Japan

Uterus transplantation (UTx) has seen increasing global adoption as an alternative for women with uterine factor infertility to achieve pregnancy. However, several medical, ethical, and social issues need to be addressed before UTx can be applied clinically. Since 2009, Japan has amassed a large database of basic research on UTx in non-human primates, but clinical application has not been realized because of conservative attitudes and prudent concerns. Nonetheless, UTx may be viable in Japan after comprehensive resolution of the concerns associated with this medical technology.

Uterus Transplantation: Challenges and the Dawn of a New Organ Transplantation

For women with absolute uterine factor infertility (AUFI), uterus transplantation (UTx) is now an alternative to gestational surrogacy or adoption in order to have a child [...]

Single bilateral ovarian venous return in uterine transplant: Validation in an orthotopic auto-transplant model in the Yucatan minipig

BACKGROUND

Uterine transplant (UT) represents an opportunity to treat absolute uterine infertility. However, the use of uterine veins for venous return, in addition to ovarian veins, significantly increases the risk of ureteral wounds in the living donor and UT time for the recipient. Our aim was to demonstrate that dual ovarian venous return is sufficient for graft viability and survival.

METHODS

Uterine orthotopic auto-transplant was performed under general anaesthesia in six Yucatan minipig sows. The uterus graft was implanted with termino-lateral anastomoses between the ovarian and external iliac veins, and between the uterine and external iliac arteries, respectively.

RESULTS

The macroscopic physical aspect of the graft was adequate in 83 % of the sows (5/6) 30 min after reperfusion with a surgical time of 439±54 min (mean anastomosis time: 153±49 min). Two sows died the day after surgery. In the four remaining sows, two uteri were necrotic and two were adequately vascularized on Day 7.

CONCLUSIONS

the learning curve was relatively fast, the sole use of bilateral ovarian venous return is possible and might reduce post-surgery morbidity in human living donors as well as UT time for the recipient.

Decellularization Methods of Uterus in Tissue Engineering

A new field of investigation which aims to design tissues and organs similar to their native origin has been developed recently, named as regenerative medicine (tissue engineering and bio-engineering). Uterus is the main organ for regeneration and contributes in the fertility. At an ultimate level, the uterus plays a role in embryo implantation, sperm migration and fetal nutrition. Uterine congenital anomalies, attained uterine lesions and immune system disorders may affect such uterine functions preventing successful pregnancy. Due to following reasons, it is essential to consider regenerative medicine as a new approach for the treatment of uterine dysfunctions to overcome the failures that cannot be treated with clinical medication.

Allogeneic uterus transplantation in a rhesus model: A short-term graft viability study

Objective

This study examined the feasibility and safety of allogeneic uterus transplantation (UTx) from a living donor and assessed short-term graft viability in a rhesus model. This research is an important step towards further clinical application of UTx in humans.

Materials and methods

Four female rhesus monkeys with regular menstrual cycles were used in this study, the animals were either donors or recipients depending on ABO blood type compatibility. Retrieval surgery was performed to connect the uterus and uterine arteries together with the ovarian uterine vein from the living donor, and the vagina of the recipient was excised. After the back table had been prepared, bilateral uterine arteries were anastomosed end-to-side with the iliac externa arteries, and bilateral ovarian uterine veins were anastomosed end-to-side with the iliac externa vena. The transplanted uterus was evaluated based on the conditions of arterial blood, and flow was evaluated by transabdominal ultrasonography one month post operation. The conditions of the transplanted uterus were examined by secondary laparotomy. The reproductive function of rhesus monkeys was evaluated on the basis of the menstrual cycle.

Results

All 4 rhesus monkeys received the transplantation surgery without any surgical complications. No injury occurred in the other organs, and no vascular injury was observed in the allogeneic uterus. All recipients survived after the surgery with a 100% short-term survival rate. All recipients resumed normal menstruation within two months after surgery.

Conclusions

Our short follow-up shows that allogeneic UTx surgery is a safe and feasible technology in the rhesus model. The arterial conditions and blood flow of the grafted uterus can be monitored by ultrasonography examination.

[Orthotopic uterus transplantation. Sheep model experiment, Cali (Colombia)]

OBJECTIVE

It has been recommended that professionals who are planning to perform uterine transplantation should first carry out animal experiments. This paper describes the procedure for uterine transplant in sheep, as well as short and medium-term results.

METHODS

Experimental surgery study in sheep subjected to uterine explantation and transplant. Four 40-50 kg sheep received uteri transplantation (orthotopic) from four live donors. End-to-side vascular anastomosis was used, the vagina was sutured on one plane and the uterus was fixed to the pelvic wall. Complications and 180-day evolution are described.

RESULTS

Transplant surgery was accomplished in the 4 sheep. Surgical time in the first procedure was 240 minutes, while the last procedure lasted 185 minutes. Warm ischemia time was reduced from 42 to 22 minutes. One sheep died on the seventh postoperative day due to an intraoperative complication unrelated to the vascular anastomosis. A second sheep developed local vaginal infection treated with metronidazole and evolved satisfactorily. No transplant rejection had occurred in the remaining 3 sheep after 6 months.

CONCLUSIONS

The ovine model allowed surgical training in experimental uterine transplant surgery. For the authors, it offered an opportunity to gain knowledge and make progress towards future uterus transplantation in women with uterine factor infertility in Colombia.

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.

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.

Clinical features of irreversible rejection after allogeneic uterus transplantation in cynomolgus macaques

Uterus transplantation (UTx) is a potential option for women with uterine factor infertility to have a child. The clinical features indicating irreversible rejection of the uterus are unknown. In our experimental series of allogeneic UTx in cynomolgus macaques, six female macaques were retrospectively examined, which were unresponsive to treatment with immunosuppressants (i.e. irreversible rejection). Clinical features including general condition, hematology, uterine size, indocyanine green (ICG) fluorescence imaging by laparotomy, and histopathological findings of the removed uterus were evaluated. In all cases, general condition was good at the time of diagnosis of irreversible rejection and thereafter. Laboratory evaluation showed temporary increases in white blood cells, lactate dehydrogenase and C-reactive protein, then these levels tended to decrease gradually. In transabdominal ultrasonography, the uterus showed time-dependent shrinkage after transient swelling at the time of diagnosis of irreversible rejection. In laparotomy, a whitish transplanted uterus was observed and enhancement of the transplanted uterus was absent in ICG fluorescence imaging. Histopathological findings in each removed uterus showed hyalinized fibrosis, endometrial deficit, lymphocytic infiltration and vasculitis. These findings suggest that uterine transplantation rejection is not fatal, in contrast to rejection of life-supporting organs. Since the transplanted uterus with irreversible rejection atrophies naturally, hysterectomy may be unnecessary.

Feasibility study for performing uterus transplantation in the Netherlands

STUDY QUESTION

Is it feasible to perform uterus transplantations (UTx) in a tertiary centre in the Netherlands?

SUMMARY ANSWER

Considering all ethical principles, surgical risks and financial aspects, we have concluded that at this time, it is not feasible to establish the UTx procedure at our hospital.

WHAT IS KNOWN ALREADY

UTx is a promising treatment for absolute uterine factor infertility. It is currently being investigated within several clinical trials worldwide and has resulted in the live birth of 19 children so far. Most UTx procedures are performed in women with the Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome, a congenital disorder characterized by absence of the uterus. In the Netherlands, the only possible option for these women for having children is adoption or surrogacy.

STUDY DESIGN SIZE DURATION

We performed a feasibility study to search for ethical, medical and financial support for performing UTx at the Amsterdam UMC, location VUmc.

PARTICIPANTS/MATERIALS SETTING METHODS

For this feasibility study, we created a special interest group, including gynaecologists, transplant surgeons, researchers and a financial advisor. Also, in collaboration with the patients' association for women with MRKH, a questionnaire study was performed to research the decision-making in possible recipients. In this paper, we present an overview of current practices and literature on UTx and discuss the results of our feasibility study.

MAIN RESULTS AND THE ROLE OF CHANCE

A high level of interest from the possible recipients became apparent from our questionnaire amongst women with MRKH. The majority (64.8%) positively considered UTx with a live donor, with 69.6% having a potential donor available. However, this 'non-life-saving transplantation' requires careful balancing of risks and benefits. The UTx procedure includes two complex surgeries and unknown consequences for the unborn child. The costs for one UTx are calculated to be around €100 000 and will not be compensated by medical insurance. The Clinical Ethics Committee places great emphasis on the principle of non-maleficence and the 'fair distribution of health services'.

LIMITATIONS REASONS FOR CAUTION

In the Netherlands, alternatives for having children are available and future collaboration with experienced foreign clinics that offer the procedure is a possibility not yet investigated.

WIDER IMPLICATIONS OF THE FINDINGS

The final assessment of this feasibility study is that that there are not enough grounds to support this procedure at our hospital at this point in time. We will closely follow the developments and will re-evaluate the feasibility in the future.

STUDY FUNDING/COMPETING INTERESTS

This feasibility study was funded by the VU Medical Center (Innovation grant 2017). No conflicts of interest have been reported relevant to the subject of all authors.

TRIAL REGISTRATION NUMBER

n.a.

A survey of public attitudes toward uterus transplantation, surrogacy, and adoption in Japan

This study aimed to evaluate the attitudes of male and female members of the public toward uterus transplantation (UTx), surrogacy, and adoption in Japan via a web-based survey. One thousand six hundred participants were recruited with equal segregation of age (20s, 30s, 40s, and 50s) and gender. We assessed the association between ethical view and gender, age, infertility, and the knowledge level of UTx, using a questionnaire. The findings were as follows. First, 36.5% and 31.0% of respondents agreed that UTx and gestational surrogacy should be approved, respectively. Second, the respondents would potentially choose to receive UTx (34.4%), gestational surrogacy (31.9%), and adoption (40.3%), if they or their partners experienced absolute uterine factor infertility. Third, 10.1%, 5.8%, and 14.3% of the respondents chose UTx, gestational surrogacy, and adoption as the most favorable option, respectively. Fourth, if their daughters suffered from absolute uterine factor infertility, 32.3% of female respondents might want to be donors, and 36.7% of male respondents might ask their wives to be donors. These data were affected by age, gender, infertility, or the knowledge level of UTx. UTx was a more acceptable option than gestational surrogacy and adoption. The effects of gender, age, infertility, and the level of knowledge of UTx are important in understanding the attitude toward UTx. On the other hand, there were concerns about the safety of UTx for recipients, donors, and babies. It is important to continue to understand public attitudes to inform the development and safety of UTx, which will enhance the discussion on the ethical consensus on UTx.

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.

Ethical and policy issues raised by uterus transplants

INTRODUCTION

In 2014, Brännström and colleagues reported the first human live birth following uterine transplantation (UTx). Research into this treatment for absolute uterine factor infertility has since grown with clinical trials currently taking place across centers in at least thirteen countries worldwide.

SOURCES OF DATA

This review summarizes and critiques the academic literature on ethical and policy issues raised by UTx.

AREAS OF AGREEMENT

There is general agreement on the importance of risk reduction and, in principle, to the sharing and maintenance of patient data on an international registry.

AREAS OF CONTROVERSY

There are numerous areas of controversy ranging from whether it is ethically justified to carry out uterus transplants at all (considering the associated health risks) to how deceased donor organs for transplant should be allocated. This review focuses on three key issues: the choice between deceased and living donors, ensuring valid consent to the procedure and access to treatment.

GROWING POINTS

UTx is presently a novel and rare procedure but is likely to become more commonplace in the foreseeable future, given the large number of surgical teams working on it worldwide.

AREAS TIMELY FOR DEVELOPING RESEARCH

Uterus transplantation requires us to re-examine fundamental questions about the ethical and social value of gestation. If eventually extended to transgender women or even to men, it may also require us to reconceptualize what it is to be a 'father' or to be a 'mother', and the definition of these terms in law.

Intra- and Postoperative Blood Flow Monitoring in a Sheep Model of Uterus Transplantation

BACKGROUND

The introduction of the opportunity to transplant a viable uterus into women for fulfilling their desire to have a child has awakened high expectations worldwide.

MATERIALS AND METHODS

A sheep model was used to evaluate tools for optimizing measurement of blood flow in uterine transplantation. Intraoperatively, blood flow was measured using unidirectional Doppler and indocyanine green (ICG) fluorescence imaging. Postoperatively, an implantable Doppler probe served as a tool for clinical monitoring the patency of anastomosed vessels.

RESULTS

ICG imaging showed complete vascularization of the uterus before and in short-term evaluation after surgery. The implantable Doppler probe proved to be highly suitable for assessing patency of vessels in a non-invasive way. Results of histology, and real-time polymerase chain reaction demonstrated viability of the transplanted uterus.

CONCLUSION

Different methods to monitor vasculature patency have proven to be advantageous in supporting both surgeons and researchers in ensuring successful implementation of uterine transplantation.

Development of an efficient perfusion-based protocol for whole-organ decellularization of the ovine uterus as a human-sized model and in vivo application of the bioscaffolds

PURPOSE

The main purpose of this investigation was to determine an efficient whole-organ decellularization protocol of a human-sized uterus and evaluate the in vivo properties of the bioscaffold.

METHODS

Twenty-four ovine uteri were included in this investigation and were decellularized by three different protocols (n 6). We performed histopathological and immunohistochemical evaluations, 4,6-diamidino-2-phenylindole (DAPI) staining, DNA quantification, MTT assay, scanning electron microscopy, biomechanical studies, and CT angiography to characterize the scaffolds. The optimized protocol was determined, and patches were grafted into the uterine horns of eight female Wistar rats. The grafts were extracted after 10 days; the opposite horns were harvested to be evaluated as controls.

RESULTS

Protocol III (perfusion with 0.25% and 0.5% SDS solution and preservation in 10% formalin) was determined as the optimized method with efficient removal of the cellular components while preserving the extracellular matrix. Also, the bioscaffolds demonstrated native-like biomechanical, structural, and vascular properties. Histological and immunohistochemical evaluations of the harvested grafts confirmed the biocompatibility and recellularization potential of bioscaffolds. Also, the grafts demonstrated higher positive reaction for CD31 and Ki67 markers compared with the control samples which indicated eminent angiogenesis properties and proliferative capacity of the implanted tissues.

CONCLUSIONS

This investigation introduces an optimized protocol for whole-organ decellularization of the human-sized uterus with native-like characteristics and a prominent potential for regeneration and angiogenesis which could be employed in in vitro and in vivo studies. To the best of our knowledge, this is the first study to report biomechanical properties and angiographic evaluations of a large animal uterine scaffold.

Current Progress in Uterus Transplantation Research in Asia

Uterus transplantation (UTx) is now a possible approach for women with absolute uterine factor infertility to deliver a child, following the first successful delivery by Brännström et al. in Sweden in September 2014. This remarkable achievement attracted major attention worldwide and caused many countries to prepare for UTx, including countries in Asia. To date, three groups have performed UTx in humans in Asia, and many others are aiming for the clinical application of UTx with accumulation of basic experimental data. Therefore, it is likely that UTx will expand rapidly in Asia in the near future, although this will depend on ethical, social and religious views in each country. With this background, herein we summarize the current progress of UTx in East, Southeast and South Asia, with the purpose of increasing understanding of the current status of basic and clinical UTx research in each country and sharing progress and knowledge to ensure future development of UTx research in Asia.

Nonhuman Primates: A Vital Model for Basic and Applied Research on Female Reproduction, Prenatal Development, and Women's Health

The comparative biology of reproduction and development in mammalian species is remarkable. Hence, because of similarities in environmental and neuroendocrine control of the reproductive axis, the cyclic function of the ovary and reproductive tract, establishment and control of the maternal-fetal-placental unit during pregnancy, and reproductive aging from puberty through menopause, nonhuman primates (NHPs) are valuable models for research related to women's reproductive health and its disorders. This chapter provides examples of research over the past 10+ years using Old World monkeys (notably macaque species), baboons, and to a lesser extent New World monkeys (especially marmosets) that contributed to our understanding of the etiology and therapies or prevention of: (1) ovarian disorders, e.g., polycystic ovary syndrome, mitochondrial DNA-based diseases from the oocyte; (2) uterine disorders, for example, endometriosis and uterine transplantation; and (3) pregnancy disorders, for example, preterm labor and delivery, environmental factors. Also, emerging opportunities such as viral (e.g., Zika) induced fetal defects and germline genomic editing to generate valuable primate models of human diseases (e.g., Huntington and muscular dystrophy) are addressed. Although the high costs, specialized resources, and ethical debate challenge the use of primates in biomedical research, their inclusion in fertility and infertility research is vital for continued improvements in women's reproductive health.

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.

Bioengineering the Uterus: An Overview of Recent Advances and Future Perspectives in Reproductive Medicine

Since the initial in vitro attempts to more complex models, research on uterine regeneration is moving towards the creation of a functional bioengineered uterus with possible clinical applications. We describe here the most relevant advances in bioengineering of the uterus published in the last decades considering the use of stem cells and biomaterials as well as future developing techniques in Regenerative Medicine.

Uterine transplantation: a systematic review

Up to 15% of the reproductive population is infertile, and 3 to 5% of these cases are caused by uterine dysfunction. This abnormality generally leads women to consider surrogacy or adoption. Uterine transplantation, although still experimental, may be an option in these cases. This systematic review will outline the recommendations, surgical aspects, immunosuppressive drugs and reproductive aspects related to experimental uterine transplantation in women.

Surgical technique for allogeneic uterus transplantation in macaques

No study has reported an animal model of uterus transplantation (UTx) using cynomolgus macaques. We aimed to establish a surgical technique of allogeneic UTx assuming the recovery of a uterus from a deceased donor in cynomolgus macaques. Four allogeneic UTxs were performed in female cynomolgus macaques. Donor surgeries comprised en bloc recovery of organs with iliac vessels on both sides, and/or abdominal aorta/vena cava after sufficient perfusion from one femoral artery or external iliac artery. Before perfusion, 150 mL of whole blood was obtained from the donor for subsequent blood transfusion to the recipient. Four uterine grafts were orthotopically transplanted to recipients. End-to-side anastomosis was performed to the iliac vessels on one side in case 1 and iliac vessels on both sides in case 2; aorto-aorto/cavo-caval anastomosis was performed in cases 3 and 4. Arterial blood flow of the uterine grafts was determined by intraoperative indocyanine green (ICG) angiography. ICG angiography results showed sufficient blood flow to all uterine grafts, and anaemia did not progress. Under appropriate immune suppression, all recipients survived for more than 90 days post-transplantation, without any surgical complications. We describe a surgical technique for allogeneic UTx in cynomolgus macaques.

Where are oncofertility and fertility preservation treatments heading in 2016?

An improvement in the survival rates of cancer patients and recent advancements in assisted reproductive technologies have led to remarkable progress in oncofertility and fertility preservation treatments. Although there are several available or emerging approaches for fertility preservation, the limited evidence for each strategy is the greatest concern. In this review, we discuss the concerns on currently available options, and propose new approaches for fertility preservation that may be available in the future.

Survey of Attitudes toward Uterus Transplantation among Japanese Women of Reproductive Age: A Cross-Sectional Study

Objective

Uterus transplantation (UTx) is a potential option for women with uterine factor infertility to have a child, but there has been no large-scale survey of the views on UTx in women of reproductive age in Japan. The present study was aimed to clarify the views of Japanese women of reproductive age on UTx for uterine factor infertility.

Methods

A questionnaire on UTx was conducted by an Internet research company in December 2014 as a cross-sectional study in 3,892 randomly chosen women aged 25 to 39 years old. Responses were analyzed from 3,098 subjects (mean age 32.1±4.2 years old), after exclusion of inappropriate respondents in screening.

Results

Of the respondents, 62.1%, 34.7% and 18.1% favored adoption, UTx and gestational surrogacy, respectively. In contrast, 7.0%, 21.9% and 63.3% opposed adoption, UTx and gestational surrogacy, respectively. In choices of candidates for UTx based on highest priority, deceased persons (33.8%) and mothers (19.0%) were favored as donors, and women with congenital absence of the uterus (54.4%) and hysterectomy due to a malignant uterine tumor (20.0%) as recipients. Regarding societal acceptance of UTx, the answer rates were 15.7% for "UTx should be permitted", 77.6% for "UTx should be permitted with discussion", and 6.7% for "UTx should not be permitted, even with discussion". Regarding personal opinions on UTx, 44.2% were in favor, 47.5% had no opinion, and 8.3% were against.

Conclusion

Our results suggest that many Japanese women of reproductive age feel that UTx is socially and individually acceptable, but that concerns requiring further discussion remain among these women. There was also a tendency for UTx to be viewed more favorably than gestational surrogacy.

A surgical technique using the ovarian vein in non-human primate models of potential living-donor surgery of uterus transplantation

AIM

Living donor surgery in organ transplantation should be performed in a minimally invasive manner under conditions that are as safe as possible. The objective of this study is to examine whether the procedure for using the ovarian vein makes donor surgery less invasive in a cynomolgus monkey model of potential living-donor surgery of uterus transplantation.

MATERIAL AND METHODS

Twenty-two female cynomolgus monkeys aged 6-9 years and with body weights of 3.55 ± 1.28 kg were used in the study. Vessels and tissues surrounding the uterus were dissected while preserving the uterine artery/vein. The deep uterine vein was used as a venous pedicle in four monkeys (Group 1), and the ovarian vein was used instead of the deep uterine vein in 18 monkeys (Group 2). With the uterine artery/vein and deep uterine vein (Group 1) or ovarian vein (Group 2) connected to the uterus, the vaginal canal was cut. The vessels were then clamped to produce a donor surgery model. Surgical time, intraoperative organ and vascular injury were examined in each animal.

RESULTS

The average surgical time from laparotomy to clamping of vessels was 230 ± 112 min in all 22 cynomolgus monkeys, and significantly longer in Group 1 (n = 4) than in Group 2 (n = 18) (393 ± 71 vs. 194 ± 84 min, p < 0.05). Surgical time in Group 2 showed a tendency to decrease in animals treated later in the study, with a significantly longer time in the first 10 monkeys compared with the last 8 (253 ± 65 vs. 120 ± 26 min, p < 0.05). All monkeys had no complications, including no injuries to other organs and no unanticipated vascular injury.

CONCLUSION

The procedure using the ovarian vein was less invasive than that using the deep uterine vein in mimicking living-donor surgery in a cynomolgus monkey model of uterus transplantation.

Towards the development of a bioengineered uterus: comparison of different protocols for rat uterus decellularization

Uterus transplantation (UTx) may be the only possible curative treatment for absolute uterine factor infertility, which affects 1 in every 500 females of fertile age. We recently presented the 6-month results from the first clinical UTx trial, describing nine live-donor procedures. This routine involves complicated surgery and requires potentially harmful immune suppression to prevent rejection. However, tissue engineering applications using biomaterials and stem cells may replace the need for a live donor, and could prevent the required immunosuppressive treatment. To investigate the basic aspects of this, we developed a novel whole-uterus scaffold design for uterus tissue engineering experiments in the rat. Decellularization was achieved by perfusion of detergents and ionic solutions. The remaining matrix and its biochemical and mechanical properties were quantitatively compared from using three different protocols. The constructs were further compared with native uterus tissue composition. Perfusion with Triton X-100/dimethyl sulfoxide/H2O led to a compact, weaker scaffold that showed evidence of a compromised matrix organization. Sodium deoxycholate/dH2O perfusion gave rise to a porous scaffold that structurally and mechanically resembled native uterus better. An innovative combination of two proteomic analyses revealed higher fibronectin and versican content in these porous scaffolds, which may explain the improved scaffold organization. Together with other important protocol-dependent differences, our results can contribute to the development of improved decellularization protocols for assorted organs. Furthermore, our study shows the first available data on decellularized whole uterus, and creates new opportunities for numerous in vitro and in vivo whole-uterus tissue engineering applications.

ESHRE Task Force on Ethics and Law 23: medically assisted reproduction in singles, lesbian and gay couples, and transsexual people†

This Task Force document discusses ethical issues arising with requests for medically assisted reproduction from people in what may be called 'non-standard' situations and relationships. The document stresses that categorically denying access to any of these groups cannot be reconciled with a human rights perspective. If there are concerns about the implications of assisted reproduction on the wellbeing of any of the persons involved, including the future child, a surrogate mother or the applicants themselves, these concerns have to be considered in the light of the available scientific evidence. When doing so it is important to avoid the use of double standards. More research is needed into the psychosocial implications of raising children in non-standard situations, especially with regard to single women, male homosexual couples and transsexual people.

Uterus allotransplantation in cynomolgus macaque: a preliminary experience with non-human primate models

AIM

Uterine transplantation (UTx) is a potential option for child-bearing in women with uterine infertility. Recovery of uterine function after allogeneic UTx in non-human primates has not been reported. The objective of this study is to establish the functional uterine transplant model in non-human primates.

METHODS

Uteri of two cynomolgus monkeys were simultaneously removed, cooled at 4°C and perfused with heparin saline. The uteri were interchanged with each other and then orthotopically transplanted. Immunosuppressive protocols included use of three agents (tacrolimus, mycophenolate mofetil and methylprednisolone) in case 1 and two agents (tacrolimus and methylprednisolone) in case 2. Transabdominal ultrasonography, vaginoscopy and biopsy of the transplanted uterine cervix were routinely conducted to monitor rejection after surgery.

RESULTS

The blood concentration of tacrolimus decreased 11 days after surgery and evidence of rejection was found in biopsy of the uterine cervix in both cases. The suspected rejection disappeared 23 days after surgery in case 1 and temporary menstruation resumed at 3 months after surgery. In case 2, blood flow to the uterine artery gradually decreased and the uterus resulted in atrophy due to ischemia, which has been triggered by rejection.

CONCLUSION

Allogeneic UTx in the cynomolgus monkeys resulted in temporary recovery of menstruation with three immunosuppressants and uterine atrophy with two immunosuppressants. This preliminary experience suggests that recovery of uterine function after allogeneic UTx in non-human primates is possible but more experiments are required.