Uterine allotransplantation in a rabbit model using aorto-caval anastomosis: a long-term viability study

Interval between balloon removal and oxytocin administration in cervical ripening with double-balloon in singleton pregnancies: An observational study

OBJECTIVE

To analyze the influence of the resting interval after removal of a double-balloon for cervical ripening and oxytocin administration on the time to onset of active labor in singleton pregnancies.

METHODS

A retrospective cohort study of women who required a cervical ripening with double-balloon was conducted between January 2019 and December 2022. We collected data for cervical ripening balloon insertion and removal, oxytocin administration, suspicious or pathological cardiotocographic trace, mode of delivery, maternal and neonatal complications, neonatal outcomes. Proportional hazards model comparing resting interval between double-balloon cervical ripening removal and oxytocin administration.

RESULTS

A total of 403 singleton pregnancies were recruited and 213 pregnant women experienced a rest of 12 h between cervical balloon removal and oxytocin administration (resting group). Oxytocin was administered immediately after balloon removal in 190 women (non-resting group). Median insertion-to-active labor interval and insertion-to-delivery interval were significantly shorter in the non-resting group: 18.5 versus 24.0 h, HR 2.59 (CI 95%: 1.97-3.41) and 24.0 versus 29.0 h, HR 2.38 (CI 95%: 1.85-3.05) respectively. Bishop score change and mode of delivery between were similar in both groups. No differences in maternal nor neonatal complications between both groups were found.

CONCLUSIONS

Oxytocin administration immediately after removal of a double-balloon for cervical ripening compared with 12 h delayed interval resulted in a shortened time from insertion to active labor onset and to delivery interval without increasing maternal or neonatal adverse outcomes.

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.

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.

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.

Use of Laser Speckle Contrast Analysis during pelvic surgery in a uterine transplantation model

Aim

Uterine transplantation (UTx) is proposed for treatment of uterine factor infertility. Our aim was to assess whether Endoscopic Laser Speckle Contrast Analysis (eLASCA) could evaluate pelvic blood flow at anastomotic sites required for sheep and rabbit UTx.

Results/methodology

eLASCA detected blood flow in rabbit UTx #7 and #9. In sheep UTx #2, #3 and #5, the results allowed us to conclude that blood flow was present in the uterine graft following transplantation; and post-UTx, the animal had heart and respiratory rates, and oxygen saturation compatible with a normal hemodynamic status.

Conclusion

These preliminary results establish the potential of Laser Speckle Contrast Analysis as noncontact and real-time tool for observation of spatially-resolved blood flow from which other parameters can be derived.

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.

Uterine Autotransplantation in the Nonhuman Primate With Preservation of the Uterine and Ovarian Vascular Pedicles

PURPOSE

To evaluate the technical feasibility of performing a uterine autotransplantation in the nonhuman primate while preserving the uterine and ovarian vascular pedicles.

METHODS

Eight (n = 8) female baboons at a primate research facility underwent a uterine autotransplant procedure with preservation of the vascular pedicles. The uterine arteries were separated from their amorphous tissue and skeletonized toward the internal iliac arteries bilaterally. A segment of the internal iliac artery was removed bilaterally along with both uterine arteries. Both ovarian veins were preserved to assist with the reperfusion of the uterine organ. Due to larger vascular pedicles in one of the primates, the uterine arteries were separated and reattached directly via end-to-end anastomosis. In another baboon, the deep uterine vein was used as a vascular pedicle rather than the ovarian vein on the left side due to adequate size and visualization.

RESULTS

Immediate tissue reperfusion occurred intraoperatively in 5 of the animals, with slower perfusion in 3 of the animals. Average warm ischemia time was 43.8 minutes while the average cold ischemia time was 174 minutes (2 hours, 54 minutes). Average total surgical time was 5.9 hours. All animals were sheltered into separate cages and monitored for behavior changes and food and drink consumption. Three of the primates expired immediately postoperatively, 2 from severe dehydration and 1 from gastric aspiration.

CONCLUSIONS

This pilot study describes a modified surgical approach for uterine transplants in the nonhuman primate. This surgical technique may be applicable to living and deceased donor uterine transplantation.

Use of biomedical photonics in gynecological surgery: a uterine transplantation model

Aim:

Uterine transplantation (UTx) has been proposed as a treatment for permanent absolute uterine factor infertility. The study aims were to compare pulse oximetry and multispectral imaging (MSI), for intraoperative tracking of uterine oxygen saturation in animal UTx models (rabbit and sheep).

Results/methodology:

Imaging results confirmed the re-establishment of adequate perfusion in the transplanted organ after surgery. Comparison of oxygen saturation values between the pre-UTx donor and post-UTx recipient, and pre-UTx and post-UTx recipient reveals a statistically significant decrease in saturation levels post-UTx.

Conclusion:

The use of MSI is the first case in gynecology and has demonstrated promise of possible future human use. MSI technique has advantages over pulse oximetry – it provides spatial information in a real-time, noncontact manner.

Transplanting wombs into women has been offered as a potential solution to treat women who have had them removed previously or who were born without one. Our aim here was to compare two techniques: pulse oximetry and multispectral imaging, for checking oxygen levels in the newly transplanted womb. The experiments were performed in two types of animals, rabbit and sheep. The use of multispectral imaging is the first case in gynecology and has demonstrated promise of possible future human use. It has advantages over pulse oximetry – it provides valuable information in a real-time, non-contact manner.

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.

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.

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).

Multispectral imaging of organ viability during uterine transplantation surgery in rabbits and sheep

Uterine transplantation surgery (UTx) has been proposed as a treatment for permanent absolute uterine factor infertility (AUFI) in the case of the congenital absence or surgical removal of the uterus. Successful surgical attachment of the organ and its associated vasculature is essential for the organ’s reperfusion and long-term viability. Spectral imaging techniques have demonstrated the potential for the measurement of hemodynamics in medical applications. These involve the measurement of reflectance spectra by acquiring images of the tissue in different wavebands. Measures of tissue constituents at each pixel can then be extracted from these spectra through modeling of the light–tissue interaction. A multispectral imaging (MSI) laparoscope was used in sheep and rabbit UTx models to study short- and long-term changes in oxygen saturation following surgery. The whole organ was imaged in the donor and recipient animals in parallel with point measurements from a pulse oximeter. Imaging results confirmed the re-establishment of adequate perfusion in the transplanted organ after surgery. Cornual oxygenation trends measured with MSI are consistent with pulse oximeter readings, showing decreased StO2 immediately after anastomosis of the blood vessels. Long-term results show recovery of StO2 to preoperative levels.

Human uterus transplantation in focus

INTRODUCTION

Uterus transplantation (UTx) is introduced as the first treatment for absolute uterine factor infertility (AUFI), affecting 1:500 fertile aged women. This review presents potential patients, research and human UTx cases.

SOURCES OF DATA

Published articles and our research experience.

AREAS OF AGREEMENT

The first UTx live births in 2014 established UTx as a possible treatment for AUFI. This was proceeded by 15 years of systematic research.

AREAS OF CONTROVERSY

Is a deceased donor UTx as effective as the proven successful live donor UTx?.

GROWING POINTS

Human UTx trials will accumulate data on risks, effectiveness and long-term consequences for donors, recipients and children. These should also include aspects of quality of life, psychological well-being and cognitive/neuropsychiatric development of children.

AREAS TIMELY FOR DEVELOPING RESEARCH

All new activities in human UTx within the coming years should be conducted as prospective observational studies, and data should also be collected within an international registry.