Xi Xia

Basic fibroblast growth factor promotes the development of human ovarian early follicles during growth in vitro

STUDY QUESTION What is the effect of basic fibroblast growth factor (bFGF) on the growth of individual early human follicles in a three-dimensional (3D) culture system in vitro? SUMMARY ANSWER The addition of 200 ng bFGF/ml improves human early follicle growth, survival and viability during growth in vitro. WHAT IS KNOWN ALREADY It has been demonstrated that bFGF enhances primordial follicle development in human ovarian tissue culture. However, the growth and survival of individual early follicles in encapsulated 3D culture have not been reported. STUDY DESIGN, SIZE, DURATION The maturation in vitro of human ovarian follicles was investigated. Ovarian tissue (n= 11) was obtained from 11 women during laparoscopic surgery for gynecological disease, after obtaining written informed consent. One hundred and fifty-four early follicles were isolated by enzymic digestion and mechanical disruption. They were individually encapsulated into alginate (1% w/v) and randomly assigned to be cultured with 0, 100, 200 or 300 ng bFGF/ml for 8 days. PARTICIPANTS/MATERIALS, SETTING, METHODS Individual follicles were cultured in minimum essential medium α (αMEM) supplemented with bFGF. Follicle survival and growth were assessed by microscopy. Follicle viability was evaluated under confocal laser scanning microscope following Calcein-AM and Ethidium homodimer-I (Ca-AM/EthD-I) staining. MAIN RESULTS AND THE ROLE OF CHANCE After 8 days in culture, all 154 follicles had increased in size. The diameter and survival rate of the follicles and the percentage with good viability were significantly higher in the group cultured with 200 ng bFGF/ml than in the group without bFGF (P < 0.05). The percentage of follicles in the pre-antral stage was significantly higher in the 200 ng bFGF/ml group than in the group without bFGF (P < 0.05), while the percentages of primordial and primary follicles were significantly lower (P < 0.05). LIMITATIONS, REASONS FOR CAUTION The study focuses on the effect of bFGF on the development of individual human early follicles in 3D culture in vitro and has limited ability to reveal the specific effect of bFGF at each different stage. The findings highlight the need to improve the acquisition and isolation of human ovarian follicles. WIDER IMPLICATIONS OF THE FINDINGS The in vitro 3D culture of human follicles with appropriate dosage of bFGF offers an effective method to investigate their development. Moreover, it allows early follicles to be cultured to an advanced stage and therefore has the potential to become an important source of mature oocytes for assisted reproductive technology; particularly as an option for fertility preservation in women, including patients with cancer. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by the National Basic Research Program of China (2011|CB944504, 2011CB944503) and the National Natural Science Foundation of China (81200470, 81000275, 31230047, 8110197). There are no conflicts of interest to declare.

Mesenchymal Stem Cells Enhance Angiogenesis and Follicle Survival in Human Cryopreserved Ovarian Cortex Transplantation

Transplantation of cryopreserved ovarian tissue is a novel technique to restore endocrine function and fertility especially for cancer patients. However, the main obstacle of the technique is massive follicle loss as a result of ischemia in the process of transplantation. Mesenchymal stem cells (MSCs) have been acknowledged to play an important role in supporting angiogenesis and stabilizing long-lasting blood vessel networks through release of angiogenic factors and differentiation into pericytes and endothelial cells. This study is aimed to investigate whether MSCs could be applied to overcome the above obstacle to support the ovarian tissue survival in the transplantation. Here we show that human MSCs could enhance the expression level of VEGF, FGF2, and especially the level of angiogenin, significantly stimulate neovascularization, and increase blood perfusion of the grafts in the cryopreserved ovarian tissue transplantation. Further studies reveal that MSCs could notably reduce the apoptotic rates of primordial follicles and decrease follicle loss in the grafted ovarian tissues. In summary, our findings demonstrate a previously unrecognized function of MSCs in improving human ovarian tissue transplantation and provide a useful strategy to optimize fertility preservation and restoration.

Human single follicle growth in vitro from cryopreserved ovarian tissue after slow freezing or vitrification

STUDY QUESTION What is the effect of human ovarian tissue cryopreservation on single follicular development in vitro? SUMMARY ANSWER Vitrification had a greater negative effect on growth and gene expression of human ovarian follicles when compared with fresh follicles. WHAT IS KNOWN ALREADY For human ovarian cortex cryopreservation, the conventional option is slow freezing while more recently vitrification has been demonstrated to maintain good quality and function of ovarian tissues. STUDY DESIGN, SIZE, DURATION Ovarian tissues were collected from 11 patients. For every patient, the ovarian cortex was divided into three samples: Fresh, slow-rate freezing (Slow) and vitrification (Vit). Tissue histology was performed and follicles were isolated for single-cell mRNA analysis and in vitro culture (IVC) in 1% alginate for 8 days. PARTICIPANTS/MATERIALS, SETTING, METHODS Follicle morphology was assessed with hematoxylin-eosin analysis. Follicles were individually embedded in alginate (1% w/v) and cultured in vitro for 8 days. Follicle survival and growth were assessed by microscopy. Follicle viability was observed after Calcein-AM and ethidium homodimer-I (Ca-AM/EthD-I) staining. Expression of genes, including GDF9 (growth differentiation factor 9), BMP15 (bone morphogenetic protein 15) and ZP3 (zona pellucida glycoprotein 3) in oocytes and AMH (anti-Mullerian hormone), FSHR (FSH receptor), CYP11A (cholesterol side-chain cleavage cytochrome P450) and STAR (steroidogenic acute regulatory protein) in GCs, was evaluated by single-cell mRNA analysis. MAIN RESULTS AND THE ROLE OF CHANCE A total of 129 follicles were separated from ovarian cortex (Fresh n = 44; Slow n = 40; Vit n = 45). The percentage of damaged oocytes and granulosa cells was significantly higher in both the Slow and Vit groups, as compared with Fresh control (P< 0.05). The growth of follicles in vitro was significantly delayed in the Vit group compared with the Fresh group (P< 0.05). Both slow freezing (P< 0.05) and vitrification (P< 0.05) down-regulated the mRNA levels of ZP3 and CYP11A compared with Fresh group, while there was no significant difference between the Slow and Vit groups (P> 0.05). Vitrification also down-regulates AMH mRNA levels compared with Fresh group (P< 0.05). LIMITATIONS, REASONS FOR CAUTION Only short-term IVC studies (8 days) are reported. Further study should be performed to examine and improve follicular development in a long-term culture system after cryopreservation. WIDER IMPLICATIONS OF THE FINDINGS This is the first comparison of gene expression and growth of single human ovarian follicles in vitro after either slow freezing or vitrification. With the decreased gene expression and growth during IVC, damage by cryopreservation still exists and needs to be minimized during the long-term IVC of follicles in the future for eventual clinical application. STUDY FUNDING/COMPETING INTERESTS This work was supported by the National Natural Science Foundation of China (31230047, 81571386, 81471508, 31429004 and 81501247), National Natural Science Foundation of Beijing (7142166) and Mega-projects of Science Research for the 12th five-year plan (2012ba132b05). There are no conflicts of interest to declare.

Mesenchymal stem cell-derived angiogenin promotes primodial follicle survival and angiogenesis in transplanted human ovarian tissue

BackgroundWe have recently reported that human bone marrow-derived mesenchymal stem cells (MSCs) facilitate angiogenesis and prevent follicle loss in xenografted human ovarian tissues. However, the mechanism underlying this effect remains to be elucidated. Thus, determining the paracrine profiles and identifying the key secreted factors in MSCs co-transplanted with ovarian grafts are essential for the future application of MSCs.MethodsIn this study, we used cytokine microarrays to identify differentially expressed proteins associated with angiogenesis in frozen-thawed ovarian tissues co-transplanted with MSCs. The function of specific secreted factors in MSCs co-transplanted with human ovarian tissues was studied via targeted blockade with short-hairpin RNAi and the use of monoclonal neutralizing antibodies.ResultsOur results showed that angiogenin (ANG) was one of the most robustly up-regulated proteins (among 42 protein we screened, 37 proteins were up-regulated). Notably, the targeted depletion of ANG with short-hairpin RNAi (shANG) or the addition of anti-ANG monoclonal neutralizing antibodies (ANG Ab) significantly reversed the MSC-stimulated angiogenesis, increased follicle numbers and protective effect on follicle apoptosis.ConclusionOur results indicate that ANG plays a critical role in regulating angiogenesis and follicle survival in xenografted human ovarian tissues. Our findings provide important insights into the molecular mechanism by which MSCs promote angiogenesis and follicle survival in transplanted ovarian tissues, thus providing a theoretical basis for their further application.

Advances in preimplantation genetic diagnosis/screening

Preimplantation genetic diagnosis (PGD) gives couples who have a high risk of transmitting genetic disorders to their baby the chance to have a healthy offspring through embryo genetic analysis and selection. Preimplantation genetic screening (PGS) is an effective method to select euploid embryos that may prevent repeated implantation failure or miscarriage. However, how and to whom PGS should be provided is a controversial topic. The first successful case of PGD of a human being was reported in 1990, and there have been tremendous improvements in this technology since then. Both embryo biopsy and genetic technologies have been improved dramatically, which increase the accuracy and expand the indications of PGD/PGS.

Mesenchymal Stem Cells Facilitate In Vitro Development of Human Preantral Follicle

Biological folliculogenesis is a lengthy and complicated process, and follicle growth microenvironment is poorly understood. Mesenchymal stem cells (MSCs) have been shown to establish a supportive microenvironment for wound repair, autoimmune diseases amelioration, and tumor development. Therefore, this study is aimed to investigate whether MSCs could help to reconstruct a microenvironment to facilitate the in vitro follicle development. Here we show human MSCs significantly promote the survival rates, increase the growth velocity, and improve the viability of preantral follicles in a dose-dependent manner. Further analyses reveal that growth differentiation factor 9 and bone morphogenetic protein 15 in oocytes and inhibin βA and transforming growth factor β1 in granulose cells within the follicles cocultured with MSCs express notably higher than those in the follicles cultured without MSCs. In summary, our findings demonstrate a previously unrecognized function of MSCs in promoting preantral follicle development and provide a useful strategy to optimize fertility preservation and restoration by facilitating in vitro follicle growth.

Basic Fibroblast Growth Factor Promotes Macaque Follicle Development In Vitro

Fertility preservation is an important type of frontier scientific research in the field of reproductive health. The culture of ovarian cortices to i) initiate primordial follicle growth and ii) procure developing follicles for later oocyte maturation is a promising fertility preservation strategy, especially for older women or cancer patients. At present, this goal remains largely unsubstantiated in primates because of the difficulty in attaining relatively large follicles via ovarian cortex culture. To overcome this hurdle, we cultured macaque monkey ovarian cortices with FSH, kit ligand (KL), basic fibroblast growth factor (bFGF), and/or epidermal growth factor (EGF). The various factors and factor combinations promoted primordial follicle development to different extents. Notably, both bFF (bFGF, 100 ng/ml and FSH, 50 ng/ml) and KF (KL, 100 ng/ml and FSH, 50 ng/ml) contributed to the activation of primordial follicles at day 12 (D12) of culture, whereas at D18, the proportions of developing follicles were significantly higher in the bFF and KF groups relative to the other treatment groups, particularly in the bFF group. Estradiol and progesterone production were also highest in the bFF group, and primary follicle diameters were the largest. Up until D24, the bFF group still exhibited the highest proportion of developing follicles. In conclusion, the bFGF-FSH combination promotes nonhuman primate primordial follicle development in vitro, with the optimal experimental window within 18 days. These results provide evidence for the future success of human ovarian cortex culture and the eventual acquisition of mature human follicles or oocytes for fertility restoration.

Up-regulation of heme oxygenase-1 expression modulates reactive oxygen species level during the cryopreservation of human seminiferous tubules

OBJECTIVE To study the effect of freezing techniques and to optimize a method for trace amounts of testicular spermatozoa from biopsed seminiferous tubules. The level of reactive oxygen species (ROS) and the gene expression of heme oxygenase-1 was evaluated. DESIGN Prospective experimental study. SETTING University-based laboratory. PATIENT(S) Eighteen adults with male fator infertility underwent testicular biopsy surgery. INTERVENTION(S) Seminiferous tubular fragments from each man were evenly allocated to three groups: fresh control, slow freezing, and vitrifiaction groups. The morphology and ROS levels before and after freezing were evaluated for seminiferous tubular fragments. The expression of heme oxygenase-1 (HO-1) at both the transcriptional and protein levels was determined. MAIN OUTCOME MEASURE(S) The morphology was analyzed by light microscopy. The ROS levels were measured with ELISA. The proliferation and differentiation were evaluated by immunohistochemistry, and the expression of HO-1 was evaluated using a real-time polymerase chain reaction (PCR) and Western blotting. RESULT(S) Decreased ROS levels and increased HO-1 expression at the transcriptional and protein levels were observed after thawing the human seminiferous tubules. The ROS level was negatively correlated with HO-1 expression. Slow freezing was more effective than vitrification in terms of HO-1 up-regulation and ROS alteration. CONCLUSION(S) Based on our study, the slow freezing technique was more effective compared with the vitrification method.

Transcriptome Landscape of Human Oocytes and Granulosa Cells Throughout Folliculogenesis

Folliculogenesis is a highly regulated process that involves bidirectional interactions of the oocytes and surrounding granulosa cells (GCs). Little is unknown, however, about the transcriptomic profiles of human oocytes and GCs throughout folliculogenesis. Here we performed a high resolution RNA-Seq of human oocytes and GCs at each follicular stage, which revealed unique transcriptional profiles, stage-specific signature genes, oocyte- and GC-derived genes that reflect ovarian reserve. We identified reciprocal cell-to-cell interactions between oocytes and GCs, including NOTCH, TGF-β signaling and gap junctions and determined the expression patterns of maternal-effect genes involved in folliculogenesis and early embryogenesis. Finally, we demonstrated robust differences between human and mice oocyte transcriptomes. This is the first comprehensive overview of the transcriptomic signatures governing the stepwise human folliculogenesis in-vivo that provides a valuable resource for basic and translational research in human reproductive biology.

A novel, noncoding-RNA-mediated, post-transcriptional mechanism of anti-Mullerian hormone regulation by the H19/let-7 axis†

Abstract In reproductive age women, the pool of primordial follicles is continuously depleted through the process of cyclic recruitment. Anti-Mullerian hormone (AMH) both inhibits the initial recruitment of primordial follicles into the growing pool and modulates the sensitivity of growing follicles to follicle stimulating hormone. Thus, AMH may be an important modulator of female infertility and ovarian reserve; however, the mechanisms regulating AMH remain unclear. To evaluate AMH levels in the absence of H19 lncRNA, H19 knockout (H19KO) mice were evaluated for analysis of ovarian AMH gene expression, protein production, and reproductive function, including assessment of follicle numbers and litter size analysis. To further investigate regulation of AMH by the H19/let-7 axis, let-7 binding sites on AMH were predicted, and in vitro studies of the effect of H19 knockdown/overexpression with let-7 rescue were performed. Lastly, response to superovulation was assessed via oocyte counts and estradiol measurements. The H19KO mouse demonstrates subfertility and accelerated follicular recruitment with increased spontaneous development of secondary, preantral, and antral follicles. Ovaries of H19KO mice have decreased AMH mRNA and protein, and AMH mRNA has a functional let-7 binding site, suggesting a plausible ncRNA-mediated mechanism for AMH regulation by H19/let-7. Lastly, in the absence of H19, superovulation results in higher estradiol and more oocytes, suggesting that H19 functions to limit the number of follicles that mature, produce estradiol, and ovulate. Thus, AMHs inhibitory actions are regulated at least in part by H19, likely via let-7, marking this ncRNA pair as important regulators of the establishment and maintenance of the follicular pool. Summary Sentence The long noncoding RNA H19 regulates AMH via let-7.