Immunology of uterine transplantation: a review

Uterine Tissue Engineering: Where We Stand and the Challenges Ahead

Tissue engineering is an innovative approach to develop allogeneic tissues and organs. The uterus is a very sensitive and complex organ, which requires refined techniques to properly regenerate and even, to rebuild itself. Many therapies were developed in 20th century to solve reproductive issues related to uterus failure and, more recently, tissue engineering techniques provided a significant evolution in this issue. Herein we aim to provide a broad overview and highlights of the general concepts involved in bioengineering to reconstruct the uterus and its tissues, focusing on strategies for tissue repair, production of uterine scaffolds, biomaterials and reproductive animal models, highlighting the most recent and effective tissue engineering protocols in literature and their application in regenerative medicine. In addition, we provide a discussion about what was achieved in uterine tissue engineering, the main limitations, the challenges to overcome and future perspectives in this research field.

Immunosuppression in uterine transplantation

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

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.

Risk of obstetrical complications in organ transplant recipient pregnancies

Pregnancy after kidney and liver transplantation is becoming relatively common, although, in both groups, maternal complications are higher than in the general population. Both mean gestational age and mean birthweight seems significantly greater for liver transplant versus kidney transplant recipients and the risk of hypertension during pregnancy seems also lower for liver transplant than kidney transplant recipients. Thus, sequelae of chronic kidney diseases have stronger adverse effects on pregnancy, leading to a higher occurrence of adverse neonatal complications. Also, gestation in heart recipients may be complicated and preeclampsia seems to occur more frequently. However, the transplanted heart seems to adapt well to changes caused by pregnancy, such as increased cardiac workload and output, and elevated maternal oxygen consumption. More problematic is pregnancy in lung transplant recipients. Spontaneous pregnancy and healthy childbirth after bone marrow grafting is relatively rare due to irradiation, but, if gestation occurs, no specific problems have been identified. Obstetrical syndromes associated with transplantation reflect the pathology of defective deep placentation, where conversion of uterine spiral arteries remains largely restricted to the decidual segment. The myometrial segments of the uteroplacental arteries have a unique vascular memory and are at great risk to develop obstructive, atherosclerotic lesions. A similar increased risk of complications already existed in pregnancies during the years before transplantation. The effect of immunosuppressive therapy remains speculative. Therefore, the main target for improving the outcome of pregnancy in women at risk is the strict antihypertensive treatment from the earliest stage of pregnancy.

Impact of pelvic radiotherapy on the female genital tract and fertility preservation measures

Radiotherapy to the pelvis can have a major and deleterious impact on the female genital tract. Despite significant advances in the technical delivery of radical pelvic radiotherapy there remains no way to avoid delivering substantial radiation doses to the ovaries and uterus for patients undergoing treatment for gynaecological cancers. Due to improved cure rates from radical chemo-radiotherapy and social trends toward delayed childbirth many women treated for cervical cancer with radical chemo-radiotherapy will wish to attempt to preserve their fertility. Whilst there are now established and emerging techniques for preserving ovarian function and ovarian tissue, there remains the difficulty of the irradiated uterus which, even if pregnancy can be achieved, results in an increased risk for pregnancy-related complications. Future developments may offer women in this difficult situation more and improved options for fertility preservation.