Effect of sphingosine-1-phosphate on activation of dormant follicles in murine and human ovarian tissue

In vitro activation of resting ovarian follicles, with the use of mechanical stress and/or pharmacological compounds, is an emerging and novel approach for infertility treatment. The aim of this study was to assess the sphingolipid, sphingosine-1-phosphate (S1P), as a potential in vitro activation agent in murine and human ovarian tissues and isolated follicles. Juvenile murine ovaries and donated human ovarian tissues, from 10 women undergoing ovarian tissue cryopreservation for fertility preservation, were incubated with or without 12 μM S1P for 3 h for quantitative PCR analysis, and 12 h for xenotransplantation or culture studies. Gene expression analyses were performed for genes downstream of the Hippo signaling pathway. Murine ovaries and isolated murine and human preantral follicles showed significantly increased mRNA expression levels of Ccn2/CCN2 following S1P treatment compared to controls. This increase was shown to be specific for the Hippo signaling pathway and for the S1P2 receptor, as co-treatment with Hippo-inhibitor, verteporfin and S1PR2 antagonist, JTE-013, reduced the S1P-induced Ccn2 gene expression in murine ovaries. Histological evaluation of human cortical tissues (5 × 5 × 1 mm; n = 30; three pieces per patient) xenografted for 6 weeks and juvenile murine ovaries cultured for 4 days (n = 9) or allografted for 2 weeks (n = 48) showed no differences in the distribution of resting or growing follicles in S1P-treated ovarian tissues compared to controls. Collectively, S1P increased Ccn2/CCN2 gene expression in isolated preantral follicles and ovarian tissue from mice and human, but it did not promote follicle activation or growth in vivo. Thus, S1P does not appear to be a potent in vitro activation agent under these experimental conditions.

Experience with transplantation of human cryopreserved ovarian tissue to a sub-peritoneal abdominal site

STUDY QUESTION

Is a sub-peritoneal abdominal site a suitable site for cryopreserved ovarian tissue transplantation?

SUMMARY ANSWER

Live births have resulted from oocytes aspirated from follicles within cryopreserved ovarian tissue transplanted in a sub-peritoneal abdominal site with similar outcomes observed in terms of number of mature oocytes recovered and embryo development from tissue transplanted to sub-peritoneal abdominal, ovarian, and pelvic sites in our clinic.

WHAT IS KNOWN ALREADY

Over 130 live births have been reported from cryopreservation of ovarian tissue and subsequent transplantation. In the majority of these, tissue was transplanted onto the remaining ovary. Although grafting to a non-ovarian, non-pelvic, sub-peritoneal abdominal site has resulted in births, it has been suggested that compromised outcomes may be expected from a non-pelvic site.

STUDY DESIGN, SIZE, DURATION

The aim of the study was to assess the outcome from cryopreserved ovarian tissue transplanted to a site out of the pelvic area; a sub-peritoneal abdominal site. These outcomes were compared to transplantation to the ovary and peritoneal pelvic area in a cohort of 17 fertility preservation women where the individual sites of follicle aspiration were known and subsequent outcomes tracked. Ovarian tissue was slow frozen using the cryoprotectants propanediol and sucrose (n = 16 women) or using dimethyl sulfoxide and sucrose (n = 1 woman). Tissue was kept at 4°C overnight prior to freezing for 1 case. Tissue was thawed appropriately and prepared on 6.0 vicryl sutures for transplantation. Tissue was placed laparoscopically into a sub-peritoneal abdominal site, a pelvic side wall peritoneal pocket and the ovary.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Following resumption of cycling, gonadotrophin stimulation commenced with FSH, LH and antagonist and a trigger was given when one follicle was >13 mm in diameter. Abdominal follicles were aspirated under ultrasound guidance trans-abdominally; ovarian and pelvic follicles were aspirated trans-vaginally. Due to an inability to differentiate pelvic from ovarian follicles at the time of ultrasound-guided oocyte retrieval, both were classified as ovarian on the side where both were present. However, on the side, where no ovary was present, outcomes from pelvic follicles were reported.

MAIN RESULTS AND THE ROLE OF CHANCE

Average time lapse between ovarian tissue harvest and graft was 6 years. Resumption of cycling occurred on average 4.2 months post first graft, regardless of graft site. Mean follicle diameter on the day of oocyte aspiration was 14 mm for all sites. Aspiration failed to retrieve an oocyte in 30% (36/120) of abdominal follicles which was similar to the other sites; ovarian 24% (21/87), pelvic 32% (31/97). A similar proportion of retrieved oocytes was mature from all sites (67% (50/75) abdominal, 68% (42/62) ovarian, 59% (34/58) pelvic). The proportion of embryos which developed on Day 2 from those fertilized was also similar in all groups (90% (34/38) abdominal, 76% (22/29) ovarian, 96% (22/23) pelvic). To our knowledge, this is the first report of outcomes from cryopreserved ovarian tissue transplanted to a sub-peritoneal abdominal site and the subsequent comparison to outcomes from the ovary and a sub-peritoneal pelvic graft, within the same cohort of patients, where tissue was slow frozen predominantly with the cryoprotectant propanediol and sucrose.

LIMITATIONS, REASONS FOR CAUTION

The study reports outcomes from a small number of women following ovarian tissue transplantation. Follicle density is an estimate only and the amount of tissue grafted varied between patients.

WIDER IMPLICATIONS OF THE FINDINGS

The demonstration of successful outcomes from cryopreserved ovarian tissue grafted to a sub-peritoneal abdominal site has significant implications for the management of women in which grafting to pelvic sites is contraindicated although it appears to be important to trigger follicle maturation at a lower than normal follicular diameter. The relative ease of oocyte retrieval at the sub-peritoneal abdominal site also has positive implications for the introduction of this approach into clinical practice.

STUDY FUNDING/COMPETING INTEREST(S)

No specific funding was used. All authors have no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Use of Simvastatin, Fibrin Clots, and Their Combination to Improve Human Ovarian Tissue Grafting for Fertility Restoration After Anti-Cancer Therapy

Anticancer treatments, particularly chemotherapy, induce ovarian damage and loss of ovarian follicles. There are limited options for fertility restoration, one of which is pre-chemotherapy cryopreservation of ovarian tissue. Transplantation of frozen-thawed human ovarian tissue from cancer survivors has resulted in live-births. There is extensive follicular loss immediately after grafting, probably due to too slow graft revascularization. To avoid this problem, it is important to develop methods to improve ovarian tissue neovascularization. The study's purpose was to investigate if treatment of murine hosts with simvastatin or/and embedding human ovarian tissue within fibrin clots can improve human ovarian tissue grafting (simvastatin and fibrin clots promote vascularization). There was a significantly higher number of follicles in group A (ungrafted control) than in group B (untreated tissue). Group C (simvastatin-treated hosts) had the highest levels of follicle atresia. Group C had significantly more proliferating follicles (Ki67-stained) than groups B and E (simvastatin-treated hosts and tissue embedded within fibrin clots), group D (tissue embedded within fibrin clots) had significantly more proliferating follicles (Ki67-stained) than group B. On immunofluorescence study, only groups D and E showed vascular structures that expressed both human and murine markers (mouse-specific platelet endothelial cell adhesion molecule, PECAM, and human-specific von Willebrand factor, vWF). Peripheral human vWF expression was significantly higher in group E than group B. Diffuse human vWF expression was significantly higher in groups A and E than groups B and C. When grafts were not embedded in fibrin, there was a significant loss of human vWF expression compared to groups A and E. This protocol may be tested to improve ovarian implantation in cancer survivors.

Epigallocatechin-3-gallate inhibits doxorubicin-induced inflammation on human ovarian tissue

Chemotherapy protocol can destroy the reproductive potential of young cancer patients. Doxorubicin (DOX) is a potent anthracycline commonly used in the treatment of numerous malignancies. The purpose of the study was to evaluate the ovarian toxicity of DOX via inflammation and the possible protective effect of the green tea polyphenol epigallocatechin-3-gallate (EGCG). Ovarian tissue of three patients was cultured with 1 µg/ml DOX and/or 10 µg/ml EGCG for 24 and 48 h. Levels of inflammatory factors were determined by quantitative Real-Time PCR, western blot, zimography, and multiplex bead-based immunoassay. Morphological evaluation, damaged follicle count and TUNEL assay were also performed. DOX influenced inflammatory responses by inducing a significant increase in the expression of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and cyclooxigenase-2 (COX-2), of inflammatory interleukins (IL), such as interleukin-6 (IL-6) and interleukin-8 (IL-8), and the inflammatory proteins mediators metalloproteinase-2 and metalloproteinase-9 (MMP2 and MMP9). IL-8 secretion in the culture supernatants and MMP9 activity also significantly raised after DOX treatment. Moreover, a histological evaluation of the ovarian tissue showed morphological damage to follicles and stroma after DOX exposure. EGCG significantly reduced DOX-induced inflammatory responses and improved the preservation of follicles. DOX-induced inflammation could be responsible for the ovarian function impairment of chemotherapy. EGCG could have a protective role in reducing DOX-mediated inflammatory responses in human ovarian tissue.

Induced Pluripotent Stem Cells from Ovarian Tissue

Yamanaka and colleagues revolutionized stem cell biology and regenerative medicine by observing that somatic cells can be reprogrammed into pluripotent stem cells. Evidence indicates that induced pluripotent stem (iPS) cells retain epigenetic memories that bias their spontaneous differentiation into the originating somatic cell type, therefore epigenetic memory may be exploited to improve tissue specific regeneration. We recently showed that iPS cells reprogrammed from ovarian granulosa cells using mouse and human tissue overwhelmingly differentiate homotypically into ovarian steroidogenic and primordial germ cells. Herein we detail a protocol for the culture of human ovarian granulosa cells. We review approaches for reprogramming human ovarian granulosa cells into iPS cells. Standard methods to induce pluripotency are outlined, concentrating on integrative retroviruses. Additionally, alternative protocols for lentivirus and Sendai virus are provided. Each approach has inherent limitations, such as reprogramming efficiency, insertional mutagenesis, and partial reprogramming. Major advances continue to be made in somatic cell reprogramming to identify an optimal approach and utilization in cell-based therapies. © 2017 by John Wiley & Sons, Inc.

Vitrification of human ovarian tissue: a practical and relevant alternative to slow freezing

BACKGROUND

Cryopreservation of ovarian tissue can be used to preserve the fertility of patients who are about to receive treatment(s) that could compromise their future ovarian function. Here we evaluate the effectiveness of a vitrification protocol by carrying out a systematic comparison with a conventional slow-freezing method on human ovarian tissue.

METHODS

Human ovarian samples (mean age 28.0 ± 1.1 years) were processed in parallel for each cryopreservation procedure: vitrification and slow-freezing. Following warming/thawing, histological observations and a TUNEL assay in ovarian follicles were performed and compared to unfrozen control.

RESULTS

Both cryopreservation protocols gave comparable histological outcomes. Percentage of intact follicles was 83.6 % following vitrification in a 1.5 M 1,2-propanediol (PrOH), 1.5 M ethylene glycol (EG) and 0.5 M raffinose solution, 80.7 % after slow-freezing in 1.5 M PrOH and 0.025 M raffinose, and 99.6 % in fresh tissue. Follicle density was unchanged by vitrification (0.6 follicles/mm2) or slow-freezing (0.5 follicles/mm2) compared to fresh tissue (0.7 follicles/mm2). Percentage of follicles with DNA fragmentation was not statistically different in vitrified (20.8 %) or slow-frozen (31.3 %) tissues compared to the unfrozen control (35.0 %). There was no difference in proportion of stroma cells with DNA fragmentation in vitrified (6.4 %) and slow-frozen (3.7 %) tissues compared to unfrozen tissue (4.2 %).

CONCLUSIONS

This vitrification protocol enables good preservation of ovarian quality post-warming. The evaluation of endocrine function after vitrification need to be perform in a higher cohort to evaluate if this protocol may offer a relevant alternative to conventional slow-freezing for the cryopreservation of human ovarian tissue.

Gene expression in human ovarian tissue after xenografting

Cryobanking and transplantation of ovarian tissue is a promising approach to restore fertility in cancer patients. However, ischemic stress following avascular ovarian cortex grafting is known to induce stromal tissue fibrosis and alterations in follicular development. The aim of the study was to analyze the impact of freeze-thawing and grafting procedures on gene expression in human ovarian tissue. Frozen-thawed ovarian tissue from 14 patients was xenografted for 7 days to nude mice and one ungrafted fragment was used as a control. Immediately after recovery, grafts were processed for RNA extraction and histological analysis. Their expression profile was screened by whole-genome oligonucleotide array (n = 4) and validated by reverse-transcriptase polymerase chain analysis (n = 10). After data filtering, the Limma package was used to build a linear regression model for each gene and to compute its fold change between tissues on Days 0 and 7. After adjusting the P-value by the Sidak method, 84 of the transcripts were significantly altered after 7 days of grafting, including matrix metalloproteinase-9 and -14 and angiogenic factors such as placental growth factor and C-X-C chemokine receptor type 4 (CXCR4). Major biological processes were related to tissue remodeling, including secretory processes, cellular adhesion and response to chemical and hormonal stimuli. Angiopoietin signaling, the interleukin-8 pathway and peroxisome proliferator-activated receptor activation were shown to be differentially regulated. On Day 7, overexpression was confirmed by PCR for interleukin-8, transforming growth factor-beta 1, matrix metalloproteinase-14 and CXCR4, compared with ungrafted controls. In conclusion, new as well as known genes involved in tissue restructuring and angiogenesis were identified and found to play a key role during the first days after human ovarian tissue transplantation. This will facilitate the development of strategies to optimize grafting techniques.