Current status and future direction of uterus transplantation

Analysis of two reperfusion techniques in uterine transplantation in an experimental model

INTRODUCTION

Uterine transplantation was developed for the treatment of absolute uterine factor infertility. As it is a new modality of transplantation, there is still room for technical improvement. A factor that impacts graft survival in organ transplantation is the warm ischemia time. In uterine transplantation specifically, at least two vascular anastomoses are performed on each side of the uterus, and the graft revascularization takes place when the vascular clamps of the arteries and veins are released on both sides simultaneously. For this reason, the warm ischemia time in uterine transplant is expected to be considerably long. The purpose of this study was to compare the sequential technique of uterine graft revascularization, which aims to reduce the warm ischemia time of the procedure, with the simultaneous revascularization technique.

MATERIAL AND METHODS

For the procedure, the uterine auto-transplantation technique was performed using 10 non-pregnant adult ewes weighing about 45 kg, divided into two groups: simultaneous revascularization group (5 animals) and sequential revascularization group (5 animals). To evaluate the groups, we analyzed the procedure and warm ischemia times, graft macroscopy, hemodynamic, laboratory, and histological parameters of the uterus.

RESULTS

The sequential revascularization technique group had similar surgical procedure times, and the warm ischemia time was significantly shorter with medians of 32 min in the sequential group vs 72 min in the simultaneous group (p < 0.008). The graft macroscopy and hemodynamic, laboratory, and histological parameters evaluated were similar between the groups.

CONCLUSIONS

The sequential revascularization technique proved to reduce the warm ischemia time in the sheep uterine auto-transplantation model without compromising graft viability.

Uterus transplantation: A bibliometric review of six-decade study from 1960 to 2024

INTRODUCTION

Some women are unable to become pregnant because they do not have a functional uterus. Over the last decade, it has become possible for these women to get pregnant through uterus transplantation, which has been the subject of numerous research studies. Therefore, the purpose of this study is to review published articles in the uterus transplantation area.

MATERIAL AND METHODS

We conducted a cross-sectional bibliometric review to study the 100 highly cited papers in the Web of Science and Scopus databases from 1960 to 2024. Our research applied bibliometric analysis to these top 100 highly cited papers. Document citation and co-occurrence analysis were used for the data study. VOSviewer along with Bibliometrix® software was used to design the maps.

RESULTS

The trend of uterus transplantation publications increased exponentially after 2010. Sweden is the leading country, followed by the USA and Spain. Fertility and Sterility, Lancet, American Journal of Transplantation, and Human Reproduction were the highly cited journals. Collaboration among countries showed that the most collaboration took place between Sweden and Spain (18), Sweden and the USA (14), the USA and Spain (8), Sweden and Australia (6), and the USA and the United Kingdom (6). Furthermore, the results found that more than one-third of the highly cited papers were review papers (39%) and 27% were clinical trial studies.

CONCLUSIONS

This bibliometric review provides a valuable contribution to the literature on uterine transplantation by synthesizing and analyzing existing research findings. It offers insights into current trends, key themes, geographic distribution, and potential areas for future research within this rapidly evolving field.

C-reactive protein orchestrates acute allograft rejection in vascularized composite allotransplantation via selective activation of monocyte subsets

INTRODUCTION

Despite advancements in transplant immunology and vascularized composite allotransplantation (VCA), the longevity of allografts remains hindered by the challenge of allograft rejection. The acute-phase response, an immune-inflammatory reaction to ischemia/reperfusion that occurs directly after allogeneic transplantation, serves as a catalyst for graft rejection. This immune response is orchestrated by acute-phase reactants through intricate crosstalk with the mononuclear phagocyte system.

OBJECTIVE

C-reactive protein (CRP), a well-known marker of inflammation, possesses pro-inflammatory properties and exacerbates ischemia/reperfusion injury. Thus, we investigated how CRP impacts acute allograft rejection.

METHODS

Prompted by clinical observations in facial VCAs, we employed a complex hindlimb transplantation model in rats to investigate the direct impact of CRP on transplant rejection.

RESULTS

Our findings demonstrate that CRP expedites allograft rejection and diminishes allograft survival by selectively activating non-classical monocytes. Therapeutic stabilization of CRP abrogates this activating effect on monocytes, thereby attenuating acute allograft rejection. Intravital imagining of graft-infiltrating, recipient-derived monocytes during the early phase of acute rejection corroborated their differential regulation by CRP and their pivotal role in driving the initial stages of graft rejection.

CONCLUSION

The differential activation of recipient-derived monocytes by CRP exacerbates the innate immune response and accelerates clinical allograft rejection. Thus, therapeutic targeting of CRP represents a novel and promising strategy for preventing acute allograft rejection and potentially mitigating chronic allograft rejection.

The trend of allogeneic tendon decellularization: literature review

Tendon injuries repair is a significant burden for orthopaedic surgeons. Finding a proper graft material to repair tendon is one of the main challenges in orthopaedics, for which the requirement of substitute for tendon repair would be different for each clinical application. Among biological scaffolds, the use of decellularized tendon increasingly represents an interesting approach to treat tendon injuries and several articles have investigated the approaches of tendon decellularization. To understand the outcomes of the the approaches of tendon decellularization on effect of tendon transplantation, a literature review was performed. This review was conducted by searching in Pubmed and Embase and 64 studies were included in this study. The findings revealed that the common approaches to decellularize tendon include chemical, physical, and enzymatic decellularization methods or their combination. With the development of tissue engineering, researchers also put forward new theories such as automatic acellular machine, 3D printing technology to manufacture acellular scaffold.

Human Tracheal Transplantation

Long-segment tracheal airway defects may be congenital or result from burns, trauma, iatrogenic intubation damage, or tumor invasion. Although airway defects <6 cm in length may be reconstructed using existing end-to-end reconstructive techniques, defects >6 cm continue to challenge surgeons worldwide. The reconstruction of long-segment tracheal defects has long been a reconstructive dilemma, and these defects are associated with significant morbidity and mortality. Many of these defects are not compatible with life or require a permanent extended-length tracheostomy that is fraught with complications including mucus plugging and tracheoesophageal fistula. Extensive circumferential tracheal defects require a reconstructive technique that provides a rigid structure able to withstand the inspiratory pressures, a structure that will biologically integrate, and contain functional ciliated epithelium to allow for normal mucociliary clearance. Tracheal transplantation has been considered the reconstructive "Holy Grail;" however, there has been a long-held scientific dogma that revascularization of the trachea was not possible. This dogma stifled research to achieve single-staged vascularized tracheal transplantation and prompted the introduction of many creative and inventive alternatives. Throughout history, alloplastic material, nonvascularized allografts, and homografts have been used to address this dilemma. However, these techniques have largely been unsuccessful. The recent introduction of a technique for single-staged vascularized tracheal transplantation may offer a solution to this dilemma and potentially a solution to management of the fatal tracheoesophageal fistula.

Functional acellular matrix for tissue repair

In view of their low immunogenicity, biomimetic internal environment, tissue- and organ-like physicochemical properties, and functionalization potential, decellularized extracellular matrix (dECM) materials attract considerable attention and are widely used in tissue engineering. This review describes the composition of extracellular matrices and their role in stem-cell differentiation, discusses the advantages and disadvantages of existing decellularization techniques, and presents methods for the functionalization and characterization of decellularized scaffolds. In addition, we discuss progress in the use of dECMs for cartilage, skin, nerve, and muscle repair and the transplantation or regeneration of different whole organs (e.g., kidneys, liver, uterus, lungs, and heart), summarize the shortcomings of using dECMs for tissue and organ repair after refunctionalization, and examine the corresponding future prospects. Thus, the present review helps to further systematize the application of functionalized dECMs in tissue/organ transplantation and keep researchers up to date on recent progress in dECM usage.

Uterine Transplantation: Recipient Patient Populations

Uterine transplantation is an emerging treatment for patients with uterine factor infertility (UFI). In order to determine patient candidacy for transplant, it is imperative to understand how to identify, counsel and treat uterine transplant recipients. In this article, we focus on patient populations with UFI, whether congenital or acquired, including Mayer-Rokitansky-Kuster-Hauser, complete androgen insensitivity syndrome, hysterectomy, and other causes of nonabsolute UFI. Complete preoperative screening of recipients should be required to assess the candidacy of each individual prior to undergoing this extensive treatment option.

Uterus transplantation-questions and answers about the procedure that is expanding the field of solid organ transplantation

Uterus transplant is a new and rapidly evolving field of solid organ transplantation designed to help women with absolute uterine-factor infertility who desire to carry their own pregnancies. The advent of this procedure and human clinical trials of uterus transplantation have raised technical, clinical, and ethical questions. We address several questions about uterus transplantation based on available literature and the clinical experience at Baylor University Medical Center, which has the largest uterus transplant program in the United States.

The Fetal-Maternal Immune Interface in Uterus Transplantation

Uterus transplants (UTxs) have been performed worldwide. Overall frequencies have been low, but globally initiated UTx programs are expected to increase clinical implementation. The uterus constitutes a unique immunological environment with specific features of tissue renewal and a receptive endometrium. Decidual immune cells facilitate embryo implantation and placenta development. Although UTx adds to the complexity of immunity during pregnancy and transplantation, the procedure provides a unique clinical and experimental model. We posit that understanding the distinct immunological properties at the interface of the transplanted uterus, the fetus and maternal circulation might provide valuable novel insights while improving outcomes for UTx. Here, we discuss immunological challenges and opportunities of UTx affecting mother, pregnancy and healthy livebirths.

Fertility preservation in women with cervical cancer

Fertility preservation in women with cervical cancer is a demanding but evolving issue. Some remarkable achievements have been reached, in particular the improvement of primary and secondary prevention and the broadening of the indications for conservative surgery up to FIGO 2018 stage IB2. Natural pregnancy rate and the rate of obstetrics complications following conservative approach is satisfactory even if not optimal. On the other hand, the use of classic strategies for fertility preservation such as oocytes or ovarian cortex freezing is extremely limited, being the uterus compromised by treatment in a high proportion of cases. In fact, the availability of uterine surrogacy can play a role in the counseling and the decision-making process. The recent advent of uterus transplantation is fascinating but, at present, cannot be viewed as a realistic solution.

Evolving ethical issues with advances in uterus transplantation

While uterus transplantation was once considered only a theoretical possibility for patients with uterine factor infertility, researchers have now developed methods of transplantation that have led to successful pregnancies with multiple children born to date. Because of the unique and significant nature of this type of research, it has been undertaken with collaboration not only with scientists and physicians but also with bioethicists, who paved the initial path for research of uterus transplantation to take place. As the science of uterus transplantation continues to advance, so too must the public dialogue among obstetrician/gynecologists, transplant surgeons, bioethicists, and other key stakeholders in defining the continued direction of research in addition to planning for the clinical implementation of uterus transplantation as a therapeutic option. Given the rapid advances in this field, the time has come to revisit the fundamental questions raised at the inception of uterus transplantation and, looking forward, determine the future of this approach given emerging data on the procedure's impact on individuals, families, and society.

Exploiting crosslinked decellularized matrix to achieve uterus regeneration and construction

Decellularized extracellular matrix (dECM) has been considered as a promising scaffold in xenotransplantation, yet natural tissue dECM is often mechanically weak and rapidly degraded, compromising the outcomes. How to restore the mechanical strength and optimise the in vivo degradation, but maintain the microstructure and maximumly suppress the immune rejection, remains challenging. For this aim, we prepared and characterised various crosslinked decellularized rabbit uterus matrix (dUECM) and evaluated in vivo performance after uterus xenotransplantation from rabbit to rat. Naturally derived genipin (GP) and procyanidins (PC) were chosen to crosslink the dUECM, producing significant mechanical enhanced crosslinked-dUECM along with prolonged enzymatic degradation rate. Xenogeneic subcutaneous graft studies revealed that PC- and GP-crosslinked dUECM experienced significant cell infiltration and caused low immune reactions, indicating the desired biocompatibility. In vivo transplantation of GP- and PC-crosslinked dUECM to a uterus circular excised rat yielded excellent recellularization ability and promoted uterus regeneration after 90 days. While the reconstruction efficacy of crosslinked dUECM is highly depended on the crosslinking degree, crosslinking condition must be carefully evaluated to balance the role of crosslinked dECM in mechanical and biological support for tissue regeneration promotion.

Uterine transplantation and IVF for congenital or acquired uterine factor infertility: A systematic review of safety and efficacy outcomes in the first 52 recipients

Uterine transplantation (UTx) associated with IVF restores fertility in women affected by absolute uterine factor infertility (AUFI). Pregnancies achieved both in women undergoing any solid organ transplantation and following IVF are associated with an increased risk of maternal and neonatal complications. This systematic review evaluated this risk in UTx-IVF treated women focusing on the safety and efficacy features of the treatment. Twenty-two studies and three press releases reporting on 52 UTx-IVF treatments were identified. Regarding the safety of treatment, 38/52 (73,1%) of surgical procedures led to the restoration of uterine function in recipients, 12/52 (23,1%) of recipients experienced post-operative complications requiring hysterectomy, and 2/52 (3,8%) of procedures failed before uterine recipients’ surgery due to intra-operative complications. Regarding the efficacy of treatment, results focused on transplanted patients showing full recovery of organ functioning: 16/38 (42,1%) of patients achieved a pregnancy, including two women who gave births twice. UTx-IVF pregnancies led to 16 deliveries and all new-borns were healthy. Six out of 16 (37,5%) UTx pregnancies faced major complications during gestation. Preterm births occurred in 10/16 (62,5%) UTx deliveries. Our data indicates that the risk of gestational and delivery complications deserves important consideration in AUFI women receiving UTx-IVF treatments. However, these observations are preliminary and need to be revised after larger series of data are published.

The Ethics of the Societal Entrenchment-approach and the case of live uterus transplantation-IVF

In 2014, the first child in the world was born after live uterus transplantation and IVF (UTx-IVF). Before and after this event, ethical aspects of UTx-IVF have been discussed in the medical and bioethical debate as well as, with varying intensity, in Swedish media and political fora. This article examines what comes to be identified as important ethical problems and solutions in the media debate of UTx-IVF in Sweden, showing specifically how problems, target groups, goals, benefits, risks and stakes are delineated and positioned. It also demonstrates how specific assumptions, norms and values are expressed and used to underpin specific positions within this debate, and how certain subjects, desires and risks become shrouded or simply omitted from it. This approach-which we label the Ethics of the Societal Entrenchment-approach, inspired by Koch and Stemerding (1994)-allows us to discuss how the identification of something as the problem helps to shape what gets to be described as a solution, and how specific solutions provide frameworks within which problems can be stated and emphasised. We also offer a critical discussion of whether some of these articulations and formations should be seen as ethically troubling, and if so, why.

Upper extremity and craniofacial vascularized composite allotransplantation: ethics and immunosuppression

Vascularized composite allotransplantation (VCA) is the name most often used to refer to the transplantation of anatomical units composed of multiple tissue types (skin, bone, muscle, tendon, nerves, vessels, etc.) when such transplants do not have the primary purpose of extending life, as is the case in the more familiar field of solid organ transplantation (SOT). A serious interest in VCA developed in the late twentieth century following advances in immunosuppression which had led to significant improvements in short and medium-term survival among SOT recipients. Several ethical concerns have been raised about VCA, with many being connected in one way or another to the limitations, burdens, and risks associated with immunosuppression. This article will focus on upper extremity and craniofacial VCA, beginning with a brief review of the history of VCA including reported outcomes, followed by a discussion of the range of ethical concerns, before exploring in greater detail how immunological issues inform and shape several of the ethical concerns.

Uterus transplantation in women who are genetically XY

Uterus transplantation is an emerging technology adding to the arsenal of treatments for infertility; specifically the only available treatment for uterine factor infertility. Ethical investigations concerning risks to uteri donors and transplant recipients have been discussed in the literature. However, missing from the discourse is the potential of uterus transplantation in other groups of genetically XY women who experience uterine factor infertility. There have been philosophical inquiries concerning uterus transplantation in genetically XY women, which includes transgender women and women with complete androgen insufficiency syndrome. We discuss the potential medical steps necessary and associated risks for uterus transplantation in genetically XY women. Presently, the medical technology does not exist to make uterus transplantation a safe and effective option for genetically XY women, however this group should not be summarily excluded from participation in trials. Laboratory research is needed to better understand and reduce medical risk and widen the field to all women who face uterine factor infertility.

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.

Value of endometrial echo pattern transformation after hCG trigger in predicting IVF pregnancy outcome: a prospective cohort study

BACKGROUND

There is much value in identifying non-invasive ways of measuring endometrial receptivity, as it has the potential to improve outcomes following in vitro fertilization (IVF). It has been suggested that endometrial echogenicity on the day of hCG administration was a good marker of endometrial receptivity. In the daily practice, we notice that patients with non-homogeneous hyperechoic endometrium on the embryo transfer day usually have lower pregnancy rates. We therefore extended the research onward transformation of echo pattern after hCG trigger to analyze the relationship between endometrial echogenicity transformation and IVF outcomes.

METHODS

A total of 146 infertile women undergoing their first IVF cycle were recruited in the prospective cohort study from August 2017 through August 2018. A series of endometrial echo pattern monitoring was carried out in these patients after hCG trigger: hCG day, from 1 through 3 days after ovum pick-up (OPU + 1, OPU + 2, OPU + 3).

RESULTS

The endometrial echogenicity value was calculated as the ratio of the hyperechogenic endometrial area over the whole endometrial area. Clinical pregnancy rate and embryo implantation rate had positive relationship with echogenicity value. The ROC curve analysis of endometrial echogenicity showed the area under curve was greatest on the second day after oocyte retrieval (OPU + 1, 2, 3 were 0.738, 0.765, 0.714 respectively) versus pregnancy. Endometrial echogenicity value on OPU + 2 had a higher predictive efficiency, and the cutoff value was 76.5%. The sensitivity was 61.3% and specificity was 82.0%. When putting the cut-off at <60%, the sensitivity was 93.8% and the specificity was 23.1%.

CONCLUSIONS

The endometrial echogenicity value on OPU + 2 was recommended to evaluate endometrial receptivity. It seemed appropriate for clinicians to provide a 'freeze all' IVF cycle and transfer in a subsequent frozen-thawed embryos cycle when echogenicity value <60% on OPU + 2.

TRIAL REGISTRATION

The registration number was ChiCTR-OOC-17012214 and the registration date was August 1st, 2017.

The vaginal microbiome in uterine transplantation

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

Gynaecology problems in puberty

With the onset of puberty a range of problems may be encountered by the young girl. Some of these include a range of gynaecological issues relating to delayed onset of puberty, delayed menarche, atypical pubertal changes and the identification of anomalies of the genital tract. The distinction between physiological events and pathological problems is important to avoid unnecessary distress and anxiety. The onset of cyclic hormonal changes also provokes a number of "non-gynaecological" problems - where the link to cyclic hormonal events is often overlooked and an important opportunity to potentially intervene and assist is missed. From a global perspective there are a range of problems that are particularly encountered with the onset of puberty including the risks of sexual violence, which in the setting of having achieved the age of reproductive potential result in unplanned pregnancies, unsafe abortions and adolescent pregnancy all of which pose life threatening risks. Sex education in its broadest sense is important for all young people. Access to contraception for adolescents is vital, such that clinicians across all streams of health care who are involved in the care of young people should take the opportunity to educate and provide this care.

Current Status of Vascularized Composite Allotransplantation

The field of vascularized composite allotransplantation (VCA) has moved from a highly experimental procedure to, at least for some patients, one of the best treatment alternatives for catastrophic tissue loss or dysfunction. Although the worldwide experience is still limited, progress has been made in translation to the clinic, and hand transplantation was recently designated standard of care and is now covered in full by the British Health System. This progress is tempered by the long-term challenges of systemic immunosuppression, and the rapidly evolving indications for VCA such as urogenital transplantation. This update will cover the state of and recent changes in the field, and an update of the Louisville VCA program as our initial recipient, the first person to receive a hand transplant in the United States celebrates the 20th anniversary of his transplant. The achievements and complications encountered over the last two decades will be reviewed. In addition, potential directions for research and collaboration as well as practical issues of how third party payers and funding are affecting growth of the field are presented.

The development of an extended normothermic ex vivo reperfusion model of the sheep uterus to evaluate organ quality after cold ischemia in relation to uterus transplantation

INTRODUCTION

Uterus transplantation has recently proved that infertility in women with uterine factor infertility can be cured. It is still an experimental procedure with numerous critical details remaining to be established, including tolerance to warm and cold ischemic insults. In preparation for human uterus transplantation trials, most teams use the sheep as a model system for research and team training, since the vasculature and the uterus is of similar size as in the human. We, therefore, aimed to develop an ex vivo sheep uterus reperfusion platform that mimics the reperfusion situation so that initial assessments and comparisons can be performed without the need for costly and labor-intensive in vivo transplantation experiments.

MATERIAL AND METHODS

Isolated sheep uteri were perfused with the preservation solution IGL-1 and were then exposed to cold ischemia for either 4 (n = 6) or 48 hours (n = 7). Uteri were then reperfused for 48 hours under normothermic conditions with an oxygenated recirculating perfusate containing growth factors and synthetic oxygen carriers. Histological and biochemical analysis of the perfusate was conducted to assess reperfusion injury.

RESULTS

Quantification of cell density indicated no significant edema in the myometrium or in the endometrium of uteri exposed to 4 hours cold ischemia and then a normothermic ex vivo reperfusion for 48 hours. Only the outer serosa layer and the inner columnar luminal epithelial cells were affected by the reperfusion. However, a much faster and severe reperfusion damage of all uterine layers were evident during the reperfusion experiment following 48 hours of cold ischemia. This was indicated by major accumulation of extracellular fluid, presence of apoptotic-labeled glandular epithelial layer and vascular endothelium. A significant accumulation of lactate was measured in the perfusate with a subsequent decrease in pH.

CONCLUSIONS

We developed a novel ex vivo sheep uterus model for prolonged perfusion. This model proved to be able to distinguish reperfusion injury-related differences associated to organ preservation. The experimental setup is a platform that can be used to conduct further studies on uterine ischemia- and reperfusion injury that may lead to improved human uterus transplantation protocols.