Development of human Graafian follicles following transplantation of human ovarian tissue into NOD/SCID/gammac null mice

Molecular Mechanism and Prevention Strategy of Chemotherapy- and Radiotherapy-Induced Ovarian Damage

Fertility preservation is an emerging discipline, which is of substantial clinical value in the care of young patients with cancer. Chemotherapy and radiation may induce ovarian damage in prepubertal girls and young women. Although many studies have explored the mechanisms implicated in ovarian toxicity during cancer treatment, its molecular pathophysiology is not fully understood. Chemotherapy may accelerate follicular apoptosis and follicle reservoir utilization and damage the ovarian stroma via multiple molecular reactions. Oxidative stress and the radiosensitivity of oocytes are the main causes of gonadal damage after radiation treatment. Fertility preservation options can be differentiated by patient age, desire for conception, treatment regimen, socioeconomic status, and treatment duration. This review will help highlight the importance of multidisciplinary oncofertility strategies for providing high-quality care to young female cancer patients.

Hormonal Stimulation of Human Ovarian Xenografts in Mice: Studying Folliculogenesis, Activation, and Oocyte Maturation

Ovarian tissue cryopreservation and banking provides a fertility preservation option for patients who cannot undergo oocyte retrieval; it is quickly becoming a critical component of assisted reproductive technology programs across the world. While the transplantation of cryopreserved ovarian tissue has resulted in over 130 live births, the field has ample room for technological improvements. Specifically, the functional timeline of grafted tissue and each patient's probability of achieving pregnancy is largely unpredictable due to patient-to-patient variability in ovarian reserve, lack of a reliable method for quantifying follicle numbers within tissue fragments, potential risk of reintroduction of cancer cells harbored in ovarian tissues, and an inability to control follicle activation rates. This review focuses on one of the most common physiological techniques used to study human ovarian tissue transplantation, xenotransplantation of human ovarian tissue to mice and endeavors to inform future studies by discussing the elements of the xenotransplantation model, challenges unique to the use of human ovarian tissue, and novel tissue engineering techniques currently under investigation.

Xenotransplantation of cryopreserved human ovarian tissue--a systematic review of MII oocyte maturation and discussion of it as a realistic option for restoring fertility after cancer treatment

OBJECTIVE

To systematically review the reporting of MII (MII) oocyte development after xenotransplantation of human ovarian tissue.

DESIGN

Systematic review in accordance with the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA).

SETTING

Not applicable.

PATIENT(S)

Not applicable.

INTERVENTION(S)

Formation of MII oocytes after xenotransplantation of human ovarian tissue.

MAIN OUTCOME MEASURE(S)

Any outcome reported in Pubmed.

RESULT(S)

Six publications were identified that report on formation of MII oocytes after xenotransplantation of human ovarian tissue.

CONCLUSION(S)

Xenografting of human ovarian tissue has proved to be a useful model for examining ovarian function and follicle development in vivo. With human follicles that have matured through xenografting, the possibility of cancer transmission and relapse can also be eliminated, because cancer cells are not able to penetrate the zona pellucida. The reported studies have demonstrated that xenografted ovarian tissue from a range of species, including humans, can produce antral follicles that contain mature (MII) oocytes, and it has been shown that mice oocytes have the potential to give rise to live young. Although some ethical questions remain unresolved, xenotransplantation may be a promising method for restoring fertility. This review furthermore describes the value of xenotransplantation as a tool in reproductive biology and discusses the ethical and potential safety issues regarding ovarian tissue xenotransplantation as a means of recovering fertility.

Efficient xenoengraftment in severe immunodeficient NOD/Shi-scid IL2rγnull mice is attributed to a lack of CD11c+B220+CD122+ cells

Xenograft animal models using immunodeficient mice have been widely applied in medical research on various human diseases. NOD/Shi-scid-IL2rγ(null) (NOG) mice are known to show an extremely high engraftment rate of xenotransplants compared with conventional immunodeficient mice. This high engraftment rate of xenotransplants in NOG mice was substantially suppressed by the transfer of spleen cells from NOD-scid mice that were devoid of NK cells. These results indicate that cell types other than splenic NK cells present in NOD-scid mice but not in NOG mice may be involved in this suppression. To identify the cell types responsible for this effect, we transferred subpopulations of spleen cells from NOD-scid mice into NOG mice and assessed the levels of human cell engraftment after human PBMC (hPBMC) transplantation. These experiments revealed that CD11c(+)B220(+) plasmacytoid dendritic cells (pDCs) from NOD-scid mice markedly inhibited engraftment of human cells. The CD11c(+)B220(+)CD122(+) cells further fractionated from the pDCs based on the expression of CD122, which is an NK cell marker strongly inhibited during hPBMC engraftment in NOG mice. Moreover, the CD122(+) cells in the pDC fraction were morphologically distinguishable from conventional CD122(+) NK cells and showed a higher rejection efficiency. The current results suggest that CD11c(+)B220(+)CD122(+) cells play an important role in xenograft rejection, and their absence in NOG mice may be critical in supporting the successful engraftment of xenotransplants.

Establishment of a novel xenograft model for human uterine leiomyoma in immunodeficient mice

Uterine leiomyomas are the most common gynecological benign tumor and greatly affect reproductive health and wellbeing, but the pathophysiology and epidemiology of uterine leiomyoma are poorly understood. One of the major reasons for the slow progress in leiomyoma research is the lack of a good in vivo model system. We therefore aimed to develop a novel model by transplanting human uterine leiomyoma xenografts in an immunodeficient mouse strain (NOD/SCID/gammac-null: NOG). Human uterine leiomyoma tissues were cut into small pieces and inserted subcutaneously into the right and left flanks of NOG mice. Estrogen supplementation was needed to maintain the features of uterine leiomyoma in xenografted tissues. After 4 weeks or 8 weeks of transplantation, xenografted tissues were harvested and analyzed regarding tissue morphology, collagen content, and proliferation and apoptosis of uterine leiomyoma smooth muscle cells. The xenografts that were harvested after 4 weeks and 8 weeks retained the histological architecture of original uterine leiomyoma tissue both in cellular and collagen components. The expression profiles of key markers of uterine leiomyoma were also maintained, including estrogen receptor, progesterone receptor, and alpha-smooth muscle actin, as judged by immunohistochemical staining. The proportion of proliferating cells was significantly increased (1.5-fold) in the xenografts after 8 weeks of transplantation, whereas that of the apoptotic cells remained unchanged. Importantly, the reproducible results were obtained with the tumor tissues derived from six patients. The present in vivo model may provide a useful tool for development of novel therapeutic strategies for uterine leiomyoma.