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

Analysis of gene and protein expression in the endometrium for validation of an ex vivo model of the equine uterus using PCR, digital and visual histopathology

In the past, most research in equine reproduction has been performed in vivo but the use of in vitro and ex vivo models has recently increased. This study aimed to evaluate the functional stability of an ex vivo hemoperfused model for equine uteri with molecular characterization of marker genes and their proteins. In addition, the study validated the respective protein expression and the aptness of the software QuPath for identifying and scoring immunohistochemically stained equine endometrium. After collection, uteri (n = 12) were flushed with preservation solution, transported to the laboratory on ice, and perfused with autologous blood for 6 h. Cycle stage was determined by examination of the ovaries for presence of Graafian follicles or corpora lutea and analysis of plasma progesterone concentration (estrus: n = 4; diestrus: n = 4; anestrus: n = 4). Samples were obtained directly after slaughter, after transportation, and during perfusion (240, 300, 360 min). mRNA expression levels of progesterone (PGR), estrogen (ESR1) and oxytocin (OXTR) receptor as well as of MKI67 (marker of cell growth) and CASP3 (marker of apoptosis) were analyzed by RT-qPCR, and correlation to protein abundance was validated by immunohistochemical staining. Endometrial samples were analyzed by visual and computer-assisted evaluation of stained antigens via QuPath. For PGR, effects of the perfusion and cycle stage on expression were found (P < 0.05), while ESR1 was affected only by cycle stage (P < 0.05) and OXTR was unaffected by perfusion and cycle stage. MKI67 was lower after 360 min of perfusion as compared to samples collected before perfusion (P < 0.05). For CASP3, differences in gene expression were found after transport and samples taken after 240 min (P < 0.05). Immunohistochemical staining revealed effects of perfusion on stromal and glandular cells for steroid hormone receptors, but not for Ki-67 and active Caspase 3. OXTR was visualized in all layers of the endometrium and was unaffected by perfusion. Comparison of QuPath and visual analysis resulted in similar results. For most cell types and stained antigens, the correlation coefficient was r > 0.5. In conclusion, the isolated hemoperfused model of the equine uterus was successfully validated at the molecular level, demonstrating stability of key marker gene expression. The utility of computer-assisted immunohistochemical analysis of equine endometrial samples was also confirmed.

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.

Surface stiffness depended gingival mesenchymal stem cell sensitivity to oxidative stress

Mesenchymal stem cells (MSCs) are widely used in the fields of cell therapy and tissue engineering, due to their wide spectrum of differentiation potential, immunomodulation function and ongoing oxidative stress (OS) reduction. Nevertheless, OS impact is often overlooked in these research fields. It is not only responsible for the induction and development of many ailments, e.g., diabetes, lung fibrosis, and cancer, moreover, OS causes stem cell death and senescence during cell therapy and tissue engineering practices. As MSCs are used to treat various tissues, they interact with different tissue-specific mechanical environments, thus it is important to understand how the mechanical environment impacts MSC sensitivity to OS. In this work, for the first time, as known to the authors, it was shown that gingival MSCs (GMSCs) sensitivity to OS depends on the stiffness of the surface, on which the cells are grown. Furthermore, the activity and expression of mitogen activated protein kinases ERK, JNK, and p38 were surface stiffness dependent. GMSCs isolated from intermediate/stiff gingiva tissue (~20 kPa) have shown the best proliferative and survival properties, then grown on the stiffest tissues mimicking polyacrylamide hydrogels (40 kPa). Therefore, MSC source might determine their sensitivity to OS in different stiffness environments and should be accounted when developing a treatment strategy.

Analysis of blood parameters and molecular endometrial markers during early reperfusion in two ovine models of uterus transplantation

The dissection of the veins is the trickiest step of Uterine transplantation (UTx). Performing the anastomosis of a single uterine vein could bring a therapeutic benefit and simplification of surgery and serve for managing unilateral venous thromboses. The objectives of this project were to evaluate the expression of early markers of ischemia-reperfusion and to compare findings following one or two vein anastomoses. Orthotopic uterine auto-transplantations were performed on an ovine model with anastomosis of either two (group 1) or one utero-ovarian veins (group 2). Blood gases, histology and ischemia- reperfusion markers transcripts (PTGS2, IL6, IL8, SOD2, C3, BAX/BCL2 and TLR4) were analyzed as well as PTGS2 protein expression using Western Blot and fluorescence immunolocalization on endometrial biopsies after 3h of reperfusion. Ten ewes were included in the experimentation, 4 were in group1, 3 in group 2, the others being sham operated controls. No significant differences were observed between the two phenotypes. Based on these results, the anastomosis of one single uterine vein appears to be an approach consistent with short-term graft survival. Further experiments will be needed to confirm the reliability of this approach, especially the long-term follow-up of the uterine graft including its ability to support gestation to term.

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.

Targeting connexins with Gap27 during cold storage of the human donor uterus protects against cell death

Uterus transplantation is an experimental infertility treatment for women with uterine factor infertility. During donor uterus retrieval and subsequent storage, ischemia and other stressors are likely to occur, resulting in the delayed restoration of organ function and increased graft rejection. The uterus expresses connexin-based hemichannels, the opening of which can promote ischemic cell death, as well as gap junctions that may expand cell death by bystander signaling. We investigated if connexin channel inhibition with connexin channel inhibitor Gap27 could protect the uterus against cell death during the storage period. The study involved 9 female patients undergoing gender-change surgery. Before uterus removal, it was exposed to in situ warm ischemia with or without reperfusion. Uterus biopsies were taken before, during, and after ischemia, with or without reperfusion, and were subsequently stored under cold (4ᵒC) or warm (37ᵒC) conditions. TUNEL cell death assay was done at various time points along the combined in vivo/ex vivo experimental timeline. We found that Gap27 protected against storage-related cell death under cold but not warm conditions when the uterus had experienced in situ ischemia/reperfusion. For in situ brief ischemia without reperfusion, Gap27 reduction of cell death was delayed and significantly less, suggesting that protection critically depends on processes initiated when the organ was still in the donor. Thus, the inclusion of the connexin channel inhibitor Gap27 during cold storage protects the uterus against cell death, and the degree of protection depends on the history of exposure to warm ischemia. Gap27 protection may be indicated for uteri from deceased donors, in which ischemia is likely because life-saving organs have retrieval priority.

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.

Ischemia and reperfusion injury in uterus transplantation: A comprehensive review

Uterus transplantation (UTx) is the only available treatment for human beings who cannot carry children out to term. However, despite several clinical studies with a very limited number of UTx many issues have to be addressed. Up to date, there is a limited number of successful UTx with livebirth and the majority was achieved with live donors. Wide clinical application is inherently limited by the lack of organs, ischemia/reperfusion injury (IRI) as well as immunosuppression after UTx. The objective of this comprehensive literature review is to discuss these arising limitations of UTx with main focus on strategies to reduce IRI. This review showed, that usage of immunosuppressants, opioids or supplements, like amino acids, protects uterus from IRI, improving rising level of antioxidants and decreasing level of oxidative stress markers. The available data of experimental and clinical studies was compiled and will be discussed.

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.

Laparoscopic uterine graft procurement and surgical autotransplantation in ovine model

Currently, uterus transplantation (UTx) is a clinical option for infertile women. Over the past three decades, treating benign or malignant gynecological diseases with minimally invasive gynecological surgery has improved, providing significant advantages over conventional open surgery. This study addresses the method used for laparoscopic live-donor ovariohysterectomy and graft harvest from a sheep model. Using a microsurgical practice, ten grafts were autotransplanted after uterine perfusion. End-to-end anastomosis techniques were used to approximate veins and arteries. Follow-ups were carried out 2-months after surgery and postoperative studies included ultrasound scan, diagnostic hysteroscopy, vascular angiography, and exploratory laparoscopy. All transplants were completed without complications. After vascular anastomosis, total reperfusion of the tissue was accomplished in all animals without confirmation of arterial or venous thrombosis. Angiographic explorations did not show any statistically significant dissimilarity in the arterial diameters between the different examination times. 3-months after uterine transplantation all animals underwent assisted reproduction techniques. Patent uterine arteries were observed 4, 8 and 12 months after the transplant. 6-months after transplantation, six sheep (60%) became pregnant with assisted reproduction practices. We noticed an increase in the degree of fibrosis of the cervix samples in non-pregnant animals of the transplant group. Laparoscopic surgery can be an advantageous approach for the uterus retrieval procedure during uterine transplantation. However, larger sample sized reports are needed in order to accomplish validation, standardization and wider use of this route.

The Key Role of Warm and Cold Ischemia in Uterus Transplantation: A Review

Introduction: Uterus transplantation (UTx) is a promising treatment for uterine infertility that has resulted in several births since 2014. Ischemia is a key step in organ transplantation because it may lead to changes jeopardizing graft viability. Method: We performed a systematic review of animal and human studies relating to uterine ischemia. Results: We retained 64 studies published since 2000. There were 35 studies in animals, 24 in humans, and five literature reviews. Modest preliminary results in large animals and humans are limited but encouraging. In small animals, pregnancies have been reported to occur after 24 h of cold ischemia (CI). In ewes, uterine contractions have been detected after 24 h of CI. Furthermore, it has been shown in animals that uterine tolerance to CI and to warm ischemia (WI) can be increased by pharmacological products. In women, mean CI time in studies of births from uteri obtained from live donors was between 2 h 47 min and 6 h 20 min from a deceased donor; with only one birth in this case. Muscle contractions have also been demonstrated in myometrial samples from women, after six or more hours of CI. Conclusion: The uterus seems to be able to tolerate a prolonged period of CI, of at least six hours. Studies of the ischemia tolerance of the uterus and ways to improve it are essential for the development of UTx, particularly for procedures using grafts from deceased donors.

Changes in the metabolic composition of storage solution with prolonged cold ischemia of the uterus

INTRODUCTION

The development of uterine transplantation (UTx) from deceased donors requires knowledge of the tolerance of the uterus to prolonged cold ischemia (CI). This can be evaluated through the use of biological parameters to assess degradation of the organ between its procurement and transplantation. The objective of this study was to analyze changes in the metabolic composition of the storage solution in cases of prolonged CI in uteri from ewes.

METHODS

Eighteen uterine auto-transplantations were performed in ewes. CI time was 1 h (T1) or 24 h (T24). Samples of Celsior® were taken when the explanted uterus was flushed (T0) and at the end of CI. A dual approach to metabolic analyses was followed: targeted biochemical analyses targeting several predefined metabolites and non-targeted metabolomics analyses based on nuclear magnetic resonance (NMR).

RESULTS

Metabolic analyses were performed on 16 explanted uteri. Metabolomic profiles differed significantly between T1 and T24 (p = 0.003). Hypoxia-associated degradation of the organ was demonstrated by the significantly higher lactate levels at T24 than at T1 (p < 0.05), accompanied by cell lysis, and significantly higher levels of creatine kinase activity in T24 than in T1 uteri (p < 0.05). Oxidative stress increased over time, with a significantly higher oxidized glutathione/glutathione ratio for T24 than for T1 uteri (p < 0.05).

CONCLUSION

The metabolic results indicate a significant degradation of the uterus during 24 h of CI. Metabolic analysis of the storage solution could be used as a non-invasive tool for evaluating uterine degradation during CI before transplantation.

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.

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.

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.

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.

Mycophenolate mofetil attenuates uterine ischaemia/reperfusion injury in a rat model

This study evaluated the effect of mycophenolate mofetil (MMF) on uterine tissue preservation following ischaemia/reperfusion (I/R) injury. Uterine I/R injury was induced in rats by clamping the lower abdominal aorta and ovarian arteries for 30 min. Group I/R + V (n = 7) received vehicle alone while Group I/R + M (n = 7) received 20 mg/kg/day MMF. Control groups underwent sham surgery and received vehicle (Group C) or 20 mg/kg/day MMF (Group M) (n = 7 for both). Four hours after detorsion, uterine tissue 8-hydroxy-2'-deoxyguanosine (8-OHdG), glutathione, malondialdehyde (MDA), myeloperoxidase (MPO), superoxide dismutase (SOD) and serum ischaemia modified albumin (IMA) concentrations were measured. Histopathological analyses were performed. The I/R + M group showed significant reduction in serum IMA and uterine tissue 8-OHdG, MDA and MPO and significant increase in SOD concentrations compared with the I/R + V group, indicating a protective effect against I/R oxidative damage (P = 0.009, P = 0.006, P = 0.002, P = 0.003 and P = 0.009, respectively). Histopathological evaluation revealed MMF treatment resulted in significantly less tissue and cellular damage and apoptosis compared with the I/R + V group. These results indicate MMF is effective in attenuating uterine tissue damage and preventing apoptosis following uterine I/R injury, probably via anti-inflammatory and anti-oxidative action.

Uterus transplantation: current progress and future prospects

Even if reproductive medicine has been remarkably successful during the past few decades, with the introduction of in vitro fertilization in the late 1970s and intracytoplasmic sperm injection in the early 1990s, it has been repeatedly mocked by infertility due to an absolute uterine factor. No treatment has been available for the women suffering from an absent or dysfunctional uterus, in terms of carrying a pregnancy. Approximately one in 500 women suffer from absolute uterine infertility, and the option so far to become a mother has been to either adopt or utilize gestational surrogacy. As of today, a total of eleven cases of human uterus transplantations have been reported worldwide, conducted in three different countries. The results of these initial experimental cases far exceed what might be expected of a novel surgical method. Many more uterus transplantations are to be expected in the near future, as other research teams' preparations are being ready to be put into clinical practice. In this review, we summarize the current worldwide experience of uterus transplantation as a treatment of absolute uterine factor infertility and the future prospects of human uterus transplantation.

Achieving uterine auto-transplantation in a sheep model using iliac vessel anastomosis: a short-term viability study

OBJECTIVE

To investigate, develop and evaluate anatomical, surgical and anastomotic aspects necessary for a successful uterine transplant in a large-animal model.

DESIGN

Sheep model; longitudinal study involving five ewes.

SETTING

Royal Veterinary College, London, UK.

POPULATION

Five ewes of proven fertility.

METHODS

The uterine allograft along with the internal iliacs, and uterine arterial and venous tree all intact were harvested en bloc. An end-to-side anastomosis was performed between the external iliac vessels and the internal iliac vessels of the graft using 6-0 polypropylene. Successful reperfusion of the graft was initially judged by the color shift of the uterus during reperfusion. Blood flow past the venous and arterial anastomotic sites was also ensured by visual inspection, together with pulse oximetry and multispectral imaging.

MAIN OUTCOME MEASURES

Operative details (retrieval, ischemic, clamping, reperfusion and recipient hysterectomy duration); physiological profiles; gross morphology and histopathology.

RESULTS

Five autotransplants were performed. One procedure was abandoned because of the inappropriate size of sheep model. Another procedure was halted because the animal suffered from respiratory failure in the immediate intra-operative period. Three transplants were completed. In those, at least two of four possible anastomoses were finished and the grafted uteri demonstrated immediate perfusion and appropriate viability 45 min post-operatively.

CONCLUSIONS

Internal to external iliac vessel anastomoses are an acceptable surgical technique that should be applied in a human model to ensure adequate subsequent uterine perfusion.

Experimental uterus transplantation

Today, most causes of infertility are successfully treated. Yet there is still a subgroup of female infertility affecting around 4%, which so far is untreatable because of an absolute uterine factor. To acquire motherhood, these women are today referred to either adoption or surrogacy. Research in the field of uterus transplantation has been evaluated in different animal models for decades and has presently reached a human clinical application as a possible treatment for absolute uterine factor infertility. Organ transplantation is no longer reserved to those with a life-threatening disease and neither is organ transplantation together with concurrent immunosuppression prohibiting pregnancy. Uterus transplantation involves four parties - recipient, donor, partner of recipient and future child - and is a subject of ethical controversies.

The protective effects of tacrolimus on rat uteri exposed to ischemia-reperfusion injury: a biochemical and histopathologic evaluation

OBJECTIVE

To evaluate the effects of the immunosuppressant tacrolimus as an antioxidant and analyze the histopathologic changes in rat uteri exposed to experimental ischemia-reperfusion (I/R) injury.

DESIGN

Experimental study.

SETTING

Experimental surgery laboratory in a university.

ANIMAL(S)

Twenty-eight female rats exposed to experimentally induced uterine I/R injury.

INTERVENTION(S)

Group I: control group; group II: uterine I/R injury-induced group; group III: pre-ischemia tacrolimus group; group IV: post-ischemia tacrolimus group.

MAIN OUTCOME MEASURE(S)

Uterine tissue malondialdehyde (MDA) level as a marker of lipid peroxidation and glutathione (GSH) level and superoxide dismutase (SOD) and catalase (CAT) activities as markers of tissue antioxidant capacity; histopathologic examination of all uterine rat tissue.

RESULT(S)

Following aortic I/R injury, MDA levels were significantly increased whereas GSH levels and CAT and SOD activities were found to be decreased compared with control animals. MDA levels were found to recover prominently after the administration of tacrolimus in both groups III and IV. Administration of tacrolimus improved uterine GSH levels and CAT activity in the tacrolimus-treated groups.

CONCLUSION(S)

Our results indicate that tacrolimus reduces oxidative damage in rat uteri exposed to I/R injury induced by distal abdominal aortic occlusion. Histologic evaluation reveals that tacrolimus attenuates the inflammatory response and protects the tissue damage induced by I/R injury.

Modified uterine allotransplantation and immunosuppression procedure in the sheep model

Objective

To develop an orthotopic, allogeneic, uterine transplantation technique and an effective immunosuppressive protocol in the sheep model.

Methods

In this pilot study, 10 sexually mature ewes were subjected to laparotomy and total abdominal hysterectomy with oophorectomy to procure uterus allografts. The cold ischemic time was 60 min. End-to-end vascular anastomosis was performed using continuous, non-interlocking sutures. Complete tissue reperfusion was achieved in all animals within 30 s after the vascular re-anastomosis, without any evidence of arterial or venous thrombosis. The immunosuppressive protocol consisted of tacrolimus, mycophenolate mofetil and methylprednisolone tablets. Graft viability was assessed by transrectal ultrasonography and second-look laparotomy at 2 and 4 weeks, respectively.

Results

Viable uterine tissue and vascular patency were observed on transrectal ultrasonography and second-look laparotomy. Histological analysis of the graft tissue (performed in one ewe) revealed normal tissue architecture with a very subtle inflammatory reaction but no edema or stasis.

Conclusion

We have developed a modified procedure that allowed us to successfully perform orthotopic, allogeneic, uterine transplantation in sheep, whose uterine and vascular anatomy (apart from the bicornuate uterus) is similar to the human anatomy, making the ovine model excellent for human uterine transplant research.

Risks for donors in uterus transplantation

Uterus transplantation (UTx) is an alternative to gestational surrogacy and adoption for patients with absolute uterine infertility. Studies have been conducted in animals, and UTx is now within the reach of clinical application in humans. Procedures in humans have been published, but many medical, ethical, and social problems and risks of UTx require discussion prior to widespread clinical application, from the perspectives of donors, recipients, families, and newborns. In this article, we summarize the burdens and risks of UTx, with a focus on donors who provide the uterus.

[Uterus transplantation. Current situation]

Except adoption, absolute uterine factor infertility lacks solution in case of motherhood desire. Gestational surrogacy is still not approved in France. Over the last decade, uterus transplantation experimentation made advances. Data from animal research, progress in immunosuppressive treatment and knowledge about pregnancy after transplantation provide a scenario in which a human allotransplantation project can become reality.

Uterus transplantation: animal research and human possibilities

Uterus transplantation research has been conducted toward its introduction in the human as a treatment of absolute uterine-factor infertility, which is considered to be the last frontier to conquer for infertility research. In this review we describe the patient populations that may benefit from uterus transplantation. The animal research on uterus transplantation conducted during the past two decades is summarized, and we describe our views regarding a future research-based human attempt.

Cyclosporine A exposure during pregnancy in mice: effects on reproductive performance in mothers and offspring

BACKGROUND

Pregnancies after organ transplantation and under immunosuppressive treatment are associated with slightly elevated risks for obstetric and post-natal complications but can usually be managed well. However, little is known about the effects of intrauterine exposure (IUE) to immunosuppressants in the growing and adult offspring. One major issue is the potentially negative effects of immunosuppressive medication on reproduction. This study investigates the effect of exposure during pregnancy to the most commonly used immunosuppressant in organ transplantation, cyclosporine A (CsA), on the reproductive outcome in mothers and offspring.

METHODS

Female C57CBA-F1 mice received 0, 10, 20 or 30 mg/kg bodyweight of CsA daily by subcutaneous mini-osmotic pumps during mating and pregnancy. Blood concentrations of CsA, implantation rates, resorption rates and fetal weights were analysed. In addition, female and male mice exposed to CsA in utero were mated to unexposed partners and pregnancy outcomes were analysed.

RESULTS

Direct maternal exposure to CsA at high doses reduced implantation rates and fetal survival. IUE to CsA reduced adolescent growth but did not affect fertility, although a reduction in birthweight was seen in offspring of females exposed to CsA in utero.

CONCLUSIONS

CsA exposure during pregnancy correlates with impaired reproductive outcome, but offspring fertility is not affected. The cause of reduction in adolescent weight gain and low birthweight in offspring of females exposed to CsA in utero need further investigation.

Experimental uterus transplantation

BACKGROUND

Uterus transplantation (UTx) is developed in animal models as a future method to treat uterine factor infertility.

METHODS

All published studies in the area of UTx research were identified. Aspects relating to surgery, cold-ischemia/reperfusion, rejection, immunosuppression, pregnancy, ethics and institutional requirements were examined.

RESULTS

Uterus retrieval surgery has been solved in animals, including primates. Studies on cold-ischemia/reperfusion indicate an ischemic tolerance of >24 h. The transplantation procedure, with vascular anastomosis, has not been fully developed in animal models, indicated by frequent thrombosis formation. Pregnancies have only been reported in syngenic/auto-UTx animal models. Several ethical issues in relation to UTx, and requirements for a team that would be suitable to undertake human UTx, exist.

CONCLUSION

Much research on UTx has been performed in appropriate animal models. Several aspects of the procedure have been optimized but some remain to be solved. It is predicted that the research will soon reach a stage that could merit introduction of human UTx as an experimental procedure.

Viability and function of the cryopreserved whole ovary: in vitro studies in the sheep

BACKGROUND

Cryopreservation of whole ovaries followed by vascular transplantation may improve long-term function in comparison to conventional cryopreservation of ovarian cortex and avascular transplantation. The aim of this study was to assess methods for the evaluation of viability and function of frozen-thawed whole ovaries.

METHODS

Ewe ovaries were flushed with either cryoprotectant (propandiol: FROZEN-PROH) or Ringer Acetate (FROZEN-RA) followed by slow freezing. Some ovaries were assessed fresh after flushing with Ringer Acetate (FRESH-RA). Assessment was done by light microscopy, biochemical response (cyclic adenosine 3',5'-monophosphate (cAMP) and steroids) during in vitro perfusion with forskolin, viability assay and cell culture.

RESULTS

Microscopy showed well-preserved morphology with the presence of small follicles in all groups before perfusion. Stromal oedema was seen after in vitro perfusion of FROZEN ovaries, and shrunken small follicles were seen only in FROZEN-RA at the end of perfusion. During in vitro perfusion, FRESH-RA ovaries responded with large increase in levels of cAMP after stimulation with forskolin. FROZEN-PROH and FROZEN-RA ovaries exhibited lower production of cAMP. Progesterone concentrations in cell cultures of dispersed ovarian cells were higher in FRESH-RA when compared with FROZEN groups. Addition of hCG to cell cultures resulted in higher progesterone levels in the FROZEN-PROH compared with FROZEN-RA. Cell viability assay showed overall viability of 60-75% with no significant difference between groups.

CONCLUSION

In vitro perfusion may prove to be a suitable method to test viability and function of frozen-thawed whole ovaries contributing to the optimization of current cryopreservation protocols.