Fertility potential and safety assessment of residual ovarian cortex in young women diagnosed with epithelial borderline and early-stage malignant ovarian tumors

OBJECTIVE

To establish the safety and quality of ovarian cortex surrounding epithelial ovarian tumors in women eligible for fertility-sparing surgery by identifying occult malignant lesions and characterizing the ovarian follicle pool.

METHODS

Multicentric retrospective study of 48 subjects (15-45 years), diagnosed with borderline ovarian tumors (BOTs) or early-stage epithelial ovarian cancers (EOCs) and eligible for fertility-sparing surgery. Histological samples of ovarian cortex surrounding tumors were analyzed to characterize the follicle pool, find any occult malignant lesion using tumor-specific markers (cytokeratin 7 and mucin 1), and quantify tumor-infiltrating lymphocytes (TILs) by CD3 and tumor associated macrophages (TAMs) by CD68.

RESULTS

Occult ovarian lesions were observed in 6 out of 45 cases investigated (14.6%), including one mucinous stage-I BOT (1/14), one serous stage-I BOT (1/13), 3 advanced-stage serous BOTs (3/11) and one early-stage serous EOC (1/7). Notably, follicle density was significantly lower in subjects diagnosed with ovarian tumors compared to controls (p < 0.001) and at a younger age. Significantly higher follicle atresia was encountered in the ovarian tumor group then in controls (20.1 ± 8.8% vs 9.2 ± 9.4%, p < 0.001) at all ages. Both TILs and TAMs were found in ovarian tumors irrespective of histotype, but no link was established with the status of the ovarian reserve.

CONCLUSIONS

Personalized counseling for fertility preservation is required in the event of BOTs and early-stage EOCs. Fertility-sparing surgery and adjuvant gamete preservation should be considered, balancing the oncological risks according to tumor stage and histotype and fertility potential, especially at a younger age.

Use of mesenchymal stem cells to enhance or restore fertility potential: a systematic review of available experimental strategies

STUDY QUESTION

To what extent does regenerative medicine with stem cell therapy help to address infertility issues for future clinical application?

SUMMARY ANSWER

Regenerative medicine using different stem cell sources is yielding promising results in terms of protecting the ovarian reserve from damage and senescence, and improving fertility potential in various preclinical settings.

WHAT IS KNOWN ALREADY

Regenerative medicine using stem cell therapy is emerging as a potential strategy to address a number of issues in the field of human reproduction. Indeed, different types of adult and fetal mesenchymal stem cells (MSCs) have been tested with promising results, owing to their ability to differentiate into different tissue lineages, move toward specific injured sites (homing), and generate a secretome with wound-healing, proangiogenic, and antioxidant capacities.

STUDY DESIGN SIZE DURATION

Guided by the checklist for preferred reporting items for systematic reviews and meta-analyses, we retrieved relevant studies from PubMed, Medline, and Embase databases until June 2023 using the following keywords: 'mesenchymal stem cells' AND 'ovarian follicles' OR 'ovarian tissue culture' OR 'ovarian follicle culture' OR 'cumulus oocyte complex'. Only peer-reviewed published articles written in English were included.

PARTICIPANTS/MATERIALS SETTING METHODS

The primary outcome for the experimental strategies was evaluation of the ovarian reserve, with a focus on follicle survival, number, and growth. Secondary outcomes involved analyses of other parameters associated with the follicle pool, such as hormones and growth factors, ovarian tissue viability markers including oxidative stress levels, oocyte growth and maturation rates, and of course pregnancy outcomes.

MAIN RESULTS AND THE ROLE OF CHANCE

Preclinical studies exploring MSCs from different animal origins and tissue sources in specific conditions were selected (n = 112), including: in vitro culture of granulosa cells, ovarian tissue and isolated ovarian follicles; ovarian tissue transplantation; and systemic or intraovarian injection after gonadotoxic or age-related follicle pool decline. Protecting the ovarian reserve from aging and gonadotoxic damage has been widely tested in vitro and in vivo using murine models and is now yielding initial data in the first ever case series of patients with premature ovarian insufficiency. Use of MSCs as feeder cells in ovarian tissue culture was found to improve follicle outcomes and oocyte competence, bringing us one step closer to future clinical application. MSCs also have proved effective at boosting revascularization in the transplantation site when grafting ovarian tissue in experimental animal models.

LIMITATIONS REASONS FOR CAUTION

While preclinical results look promising in terms of protecting the ovarian reserve in different experimental models (especially those in vitro using various mammal experimental models and in vivo using murine models), there is still a lot of work to do before this approach can be considered safe and successfully implemented in a clinical setting.

WIDER IMPLICATIONS OF THE FINDINGS

All gathered data on the one hand show that regenerative medicine techniques are quickly gaining ground among innovative techniques being developed for future clinical application in the field of reproductive medicine. After proving MSC effectiveness in preclinical settings, there is still a lot of work to do before MSCs can be safely and effectively used in different clinical applications.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by grants from the Fonds National de la Recherche Scientifique de Belgique (FNRS-PDR T.0077.14, FNRS-CDR J.0063.20, and grant 5/4/150/5 awarded to Marie-Madeleine Dolmans), Fonds Spéciaux de Recherche, and the Fondation St Luc. None of the authors have any competing interest to disclose.

REGISTRATION NUMBER

N/A.

Importance of oxygen tension in human ovarian tissue in vitro culture

STUDY QUESTION

Is there any difference between 20% and 5% oxygen (O2) tension in vitro culture (IVC) on the viability and quality of human follicles contained in cultured ovarian cortex?

SUMMARY ANSWER

An O2 tension of 5% yields higher follicle viability and quality than does 20% O2 tension after 6 days of IVC.

WHAT IS KNOWN ALREADY

The primordial follicle (PMF) pool resides within the ovarian cortex, where the in vivo O2 tension ranges between 2% and 8%. Some studies suggest that lowering O2 tension to physiological levels may improve in vitro follicle quality rates.

STUDY DESIGN, SIZE, DURATION

This prospective experimental study included frozen-thawed ovarian cortex from six adult patients (mean age: 28.5 years; age range: 26-31 years) who were undergoing laparoscopic surgery for non-ovarian diseases. Ovarian cortical fragments were cultured for 6 days at (i) 20% O2 with 5% CO2 and (ii) 5% O2 with 5% CO2. Non-cultured fragments served as controls.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Cortical fragments were used for the following analyses: hematoxylin and eosin staining for follicle count and classification; Ki67 staining to evaluate PMF proliferation; cleaved caspase-3 immunostaining to identify follicle apoptosis; 8-hydroxy-2-deoxyguanosine and gamma-H2AX (γH2AX) immunolabeling to detect oxidative stress damage and DNA double-strand breaks (DSBs) in oocytes and granulosa cells (GCs); and β-galactosidase staining to assess follicle senescence. Droplet digital PCR was also performed to further explore the gene expression of superoxide dismutase 2 (SOD2) and glutathione peroxidase 4 (GPX4) from the antioxidant defense system and cyclin-dependent kinase inhibitors (p21 and p16) as tissue senescence-related genes.

MAIN RESULTS AND THE ROLE OF CHANCE

Apoptosis (P = 0.002) and follicle senescence (P < 0.001) rates were significantly lower in the 5% O2 group than in the 20% O2 group. Moreover, GCs in follicles in the 20% O2 group exhibited significantly (P < 0.001) higher oxidative stress damage rates than those in the 5% O2 group. DNA DSB damage rates in GCs of follicles were also significantly higher (P = 0.001) in the 20% O2 group than in the 5% O2 group. SOD2 expression was significantly greater in the 5% O2 group compared to the 20% O2 group (P = 0.04) and the non-cultured group (P = 0.002). Expression of p21 was significantly increased in both the 20% O2 (P = 0.03) and 5% O2 (P = 0.008) groups compared to the non-cultured group. Moreover, the 20% O2 group showed significantly greater p16 expression (P = 0.04) than the non-cultured group, while no significant variation was observed between the 5% O2 and no culture groups.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

This study focuses on improving follicle outcomes during the first step of ovarian tissue IVC, where follicles remain in situ within the tissue. The impact of O2 tension in further steps, such as secondary follicle isolation and maturation, was not investigated here.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings suggest that 5% O2 tension culture is a promising step toward potentially solving the problem of poor follicle viability after IVC.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the Fonds National de la Recherche Scientifique de Belgique (FNRS-PDR T.0064.22, CDR J.0063.20 and grant 5/4/150/5 awarded to M.M.D.). The authors have nothing to disclose.

Role of apoptosis and autophagy in ovarian follicle pool decline in children and women diagnosed with benign or malignant extra-ovarian conditions

STUDY QUESTION

Which biological mechanisms are responsible for physiological ovarian reserve decline owing to aging, or pathological follicle depletion triggered by inflammation or a pro-oxidant environment throughout a woman's lifetime?

SUMMARY ANSWER

Ovarian follicle pool size is modulated by both apoptosis and autophagy, the first responsible for its physiological decline over time and increasing in the event of prior chemotherapy in children, and the latter playing a major role in physiological ovarian follicle pool diminution before puberty.

WHAT IS KNOWN ALREADY

Among the different pathways of controlled cell death, apoptosis and autophagy are implicated in follicle loss. Apoptosis participates in eliminating damaged follicles, such as those impaired by chemotherapy (CHT), but its involvement in physiological age-related follicle decline is less well understood. Autophagy has proved crucial in follicle quiescence maintenance in murine models, but its contribution to human follicle pool modulation is still unclear.

STUDY DESIGN, SIZE, DURATION

This retrospective study included 84 patients with benign or malignant extra-ovarian conditions aged between 1 and 35 years, with ovarian tissue stored for histological analyses at the time of cryopreservation (between 2012 and 2021) at a tertiary care center.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Ovarian fragments were used for the following analyses: hematoxylin and eosin staining for follicle count and classification; cleaved caspase-3 immunostaining to identify follicle apoptosis; and microtubule-associated proteins 1A/1B light chain 3B immunolabeling to detect follicle autophagy. Transmission electron microscopy was also carried out to investigate ultrastructural features of oocytes and granulosa cells. All analyses stratified patients by age, menarchal status (premenarchal = 32; postmenarchal = 52), potentially gonadotoxic CHT before cryopreservation (n = 14), presence of endometriosis and use of hormonal treatment.

MAIN RESULTS AND THE ROLE OF CHANCE

Premenarchal patients had a larger follicle pool in terms of total follicle density [mean, range 4979.98 (342.2-21789) versus 918.8 (26.18-3983), P < 0.001], but higher rates of morphologically abnormal [8.52 (0-25.37)% versus 3.54 (0-17.5)%, P < 0.001] and atretic [15.8 (0‒31.85)% versus 10.6 (0-33.33)%, P < 0.01] follicles than postmenarchal subjects. Apoptosis rates did not change with increasing age [27.94 (0-93.2)% in prepubertal subjects and 29.5 (0-100)% in postpubertal subjects], but autophagic follicles were around 10 times more common in premenarchal than postmenarchal subjects [10.21 (0-62.3)% versus 1.34 (0-25)%, P < 0.001], playing a crucial role in age-related follicle decline and elimination of 'abnormal' follicles, that are rarely seen after menarche. The impact of diagnosis and previous CHT varied according to age. In premenarchal patients with previous CHT, significantly more apoptotic [40.22 (0-100)% versus 26.79 (0-87)%, P < 0.05] and fewer abnormal [3.84 (0-10-76)% versus 9.83 (0-25.37)%, P < 0.01] follicles were detected than in subjects with no CHT prior to ovarian tissue cryopreservation, suggesting a direct effect on follicle elimination, especially of those with abnormalities. In postmenarchal subjects with previous CHT, quiescent follicle rates were lower than in patients with no CHT before tissue freezing [71.57 (0-100)% versus 85.89 (50-100)%, P < 0.05], suggesting accelerated follicle activation and growth. Moreover, increased autophagic activity was observed in the event of a cancer diagnosis compared to benign conditions after puberty [26.27 (0-100)% versus 9.48 (0-29.41)%, respectively, P < 0.05].

LIMITATIONS, REASONS FOR CAUTION

The impact of specific CHT protocols could not be investigated since the group of patients with previous CHT was highly heterogeneous.

WIDER IMPLICATIONS OF THE FINDINGS

This study yields a deeper understanding of regulation of the follicle pool decline, showing for the first time that both apoptosis and autophagy pathways are involved in physiological follicle depletion, the latter being crucial before puberty. Moreover, our data showed a different response to non-physiological damage according to age, with higher apoptosis rates only in premenarchal subjects with previous CHT, confirming that this pathway is activated by drugs known to induce DNA damage in oocytes, such as alkylating agents, but not by cancer itself.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the Fonds National de la Recherche Scientifique de Belgique (F.R.S.-FNRS/FRIA FC29657 awarded to L.C., CDR J.0063.20 and grant 5/4/150/5 awarded to M.M.D.), grants from the Fondation contre le Cancer (grant 2018-042 awarded to A.Ca.), the Fondazione Comunitaria del Varesotto and Provincia di Varese ('Amalia Griffini' Fellowship in Gynecology and Obstetrics awarded to A.Ce.), Fonds Spéciaux de Recherche, Fondation St Luc and donations from the Ferrero family. The authors have no competing interests to declare.

TRIAL REGISTRAION NUMBER

N/A.

A synopsis of global frontiers in fertility preservation

Since 2007, the Oncofertility Consortium Annual Conference has brought together a diverse network of individuals from a wide range of backgrounds and professional levels to disseminate emerging basic and clinical research findings in fertility preservation. This network also developed enduring educational materials to accelerate the pace and quality of field-wide scientific communication. Between 2007 and 2019, the Oncofertility Consortium Annual Conference was held as an in-person event in Chicago, IL. The conference attracted approximately 250 attendees each year representing 20 countries around the world. In 2020, however, the COVID-19 pandemic disrupted this paradigm and precluded an in-person meeting. Nevertheless, there remained an undeniable demand for the oncofertility community to convene. To maintain the momentum of the field, the Oncofertility Consortium hosted a day-long virtual meeting on March 5, 2021, with the theme of "Oncofertility Around the Globe" to highlight the diversity of clinical care and translational research that is ongoing around the world in this discipline. This virtual meeting was hosted using the vFairs ® conference platform and allowed over 700 people to participate, many of whom were first-time conference attendees. The agenda featured concurrent sessions from presenters in six continents which provided attendees a complete overview of the field and furthered our mission to create a global community of oncofertility practice. This paper provides a synopsis of talks delivered at this event and highlights the new advances and frontiers in the fields of oncofertility and fertility preservation around the globe from clinical practice and patient-centered efforts to translational research.

O-034 Xenotransplantation of ovarian cortex tissue from young girls with Turner Syndrome in a mice model: is normal follicular development possible?

Study question

Does aneuploidy of granulosa and stromal cells affect folliculogenesis of small follicles in girls with mosaic Turner Syndrome (TS)?

Summary answer

Our results showed that despite high level aneuploidy in granulosa cells of small follicles and stromal cells folliculogenesis was not affected in mosaic TS patients.

What is known already

In 2018 the TurnerFertility study was initiated to explore if ovarian tissue cryopreservation (OTC) is a viable option for TS patients to preserve their fertility at an early age. In this study, karyotyping of ovarian cells in 7 mosaic TS patients showed that the majority of oocytes had a normal X chromosomal content, while granulosa and stromal cells were aneuploid. Until now, it remains unclear if follicular development is affected, and consequently the success rate of autotransplantation after OTC in girls with TS.

Study design, size, duration

A collaboration project was initiated between Radboudumc, The Netherlands and UCLouvain, Belgium to assess folliculogenesis of small follicles in TS patients by using a xenograft mice model. Ovarian cortex tissue was obtained from 18 mosaic TS patients and 13 age-matched controls.

Participants/materials, setting, methods

After unilateral ovariectomy, one fragment of the ovarian tissue was used for research. One part of this fragment was used for fluorescence in situ hybridization (FISH) to determine the X chromosomal content of ovarian cells in non-grafted tissue. The other part was xenografted into severe combined immunodeficient mice. After 5 months, grafts were retrieved and analysed for aneuploidy by FISH. The expression of 6 proteins essential for folliculogenesis was analysed by immunohistochemistry and immunofluorescence.

Main results and the role of chance

The mean follicle density in ovarian tissue of TS patients before grafting was significantly lower compared to controls. FISH analysis showed that 97% of the oocytes in non-grafted tissue had a normal X chromosomal content. Follicles of TS patients contained mainly or exclusively 45,X granulosa cells, but different levels of X chromosome mosaicism between TS patients and between follicles of the same patient were observed.

In total, 12/18 grafts contained follicles after 5 months xenografting. Follicle density of both TS patients and controls decreased significantly after xenotransplantation. Despite the presence of high level aneuploidy in granulosa and stromal cells in the tissue before grafting, secondary and even antral follicles were observed after xenotransplantation. Remarkably, a shift from high to low percentage of 45,X granulosa cells was observed during folliculogenesis. Immunohistochemistry showed that proliferating cell nuclear antigen (PCNA) positive follicles from TS patients increased during grafting to almost 100%. Secretion of anti-Müllerian hormone by granulosa cells was impaired before grafting in peri/postpubertal TS girls, but recovered after grafting. Expression of c-kit receptor and bone morphogenetic protein 15 (BMP15) in peri/postpubertal TS patients remained abnormal after xenotransplantation, while secretion of growth differentiation factor 9 (GDF9) and kit ligand was similar to controls.

Limitations, reasons for caution

In this study, only ovarian tissue of mosaic TS patients was examined, because the chances of finding ovarian follicles in this subgroup is considerably higher than in other TS patients. Subtle effects of reduced expression of c-kit receptor and BMP15 on folliculogenesis might have gone unnoticed.

Wider implications of the findings

Small follicles of mosaic TS patients are able to grow to secondary and antral follicles, despite the presence of aneuploid granulosa and stromal cells before grafting. Therefore, OTC could be a realistic option for young mosaic TS patients to preserve their fertility provided that sufficient numbers of follicles are present.

Trial registration number

NCT03381300

O-038 Role of apoptosis and autophagy in ovarian follicle pool decline from birth to late reproductive age and after gonadotoxic chemotherapeutic treatments

Study question

Which biological mechanisms are responsible for physiological age-dependent and non-physiological ovarian reserve decline throughout a woman’s life?

Summary answer

Ovarian follicle pool size is modulated by both apoptosis and autophagy, the latter playing a major role in its decline before puberty.

What is known already

Among different pathways of controlled cell death, apoptosis and autophagy are both involved in follicle death. Apoptosis participtes in eliminating damaged follicles, like those affected by chemotherapy (CHT)-induced DNA damage, but its role in physiological age-related follicle decline is less understood. Autophagy has proved crucial in follicle quiescence maintenance in murine models, but its contribution to human follicle pool modulation is still unclear.

Study design, size, duration

Eighty-four patients aged between 1 and 35 years, with ovarian tissue stored for histological analyses at the time of cryopreservation (between 2012 and 2021) at the Université Catholique de Louvain (Belgium) were included in retrospective evaluations.

Participants/materials, setting, methods

Ovarian fragments were used for the following analyses: hematoxylin and eosin staining for follicle count and classification; caspase-3 immunostaining to identify follicle apoptosis; and microtubule-associated proteins 1A/1B light chain 3B (LC3B) immunolabeling to detect follicle autophagy. Ovarian fragments from 9 patients were assigned for transmission electron microscopy to investigate ultrastructural features of oocytes and granulosa cells. All analyses were conducted stratifying patients by age, menarchal status (premenarchal=32; postmenarchal=52), and potentially gonadotoxic CHT before cryopreservation (n = 14).

Main results and the role of chance

Premenarchal patients had a larger follicle pool in terms of total follicle density (4979.98±4952.16 vs 918.8±903.86, p &lt; 0.0001), but higher rates of morphologically abnormal (8.52±6.48% vs 3.54±4.54%, p &lt; 0.0001) and atretic follicles (15.8±9.14% vs 10.6±9.43%, p = 0.01) than postmenarchal subjects. Apoptosis rates did not change with increasing age (27.94±28.78% in prepubertal subjects and 29.5±33.58% in postpubertal subjects). Autophagic follicles were around 10 times more common in premenarchal compared to postmenarchal subjects (10.21±16.% vs 1.34±4.02%, p &lt; 0.0001), playing a crucial role in age-related follicle decline and elimination of ‘abnormal follicles’, that are rarely seen after menarche. The impact of previous CHT varied according to age. In premenarchal patients with previous CHT, significantly more apoptotic (40.22±40.44% vs 26.79±25.35%, p = 0.04) and fewer abnormal (3.84±3.91% vs 9.83±6.5%, p = 0.02) follicles were detected than in those with no CHT prior to ovarian tissue cryopreservation, suggesting a direct effect on follicle elimination, especially of those with abnormalities. In postmenarchal subjects with previous CHT, lower quiescent follicle rates were observed compared to patients with no CHT before tissue freezing (70.1±36.36% vs 85.89±12.61%, p = 0.04), suggesting accelerated follicle activation and growth.

Limitations, reasons for caution

The present study could not investigate the impact of specific CHT protocols, since the group of patients with previous CHT was highly heterogeneous. However, these patients could not be excluded a priori, since the effect of follicle pool depletion has not been fully elucidated.

Wider implications of the findings

This study yields a deeper understanding of follicle pool decline regulation, evidencing for the first time that (i) different cell death pathways are involved in physiological and non-physiological follicle depletion, and (ii) the follicle pool responds differently to gonadotoxic damage according to age and ovarian reserve size.

Trial registration number

N/A

O-192 Modulating hypoxia and oxidative stress in human ovarian tissue xenografts using adipose tissue-derived stem cells

Study question

To investigate whether adipose tissue-derived stem cells (ASCs) modulate hypoxia and oxidative stress in human ovarian tissue transplants to reduce early follicle loss.

Summary answer

ASCs protect the follicle pool by mitigating the hypoxia-related response through HIF1↑ signaling in human xenografts and enhancing revascularization by ensuring faster tissue reperfusion.

What is known already

ASCs are known for their angiogenic potential and capacity to boost angiogenesis by secreting growth factors and differentiating into vessels in numerous models of wound healing in regenerative medicine. In a 2-step ovarian tissue xenotransplantation involving grafting inside a fibrin scaffold two weeks prior to transplantation, ASCs reduced follicle loss after short- and long-term grafting, as well as abnormal follicle activation, by increasing reoxygenation and revascularization in human xenografts.

Study design, size, duration

Prospective experimental study. Cryopreserved ovarian cortex from five adult women was transplanted to 30 nude mice, with or without ASCs (ASC group; OT group). Ovarian grafts were retrieved on days 3 (n = 5), 10 (n = 5) and 21 (n = 5). One piece of ovarian tissue per patient was fixed for analysis after thawing to serve as non-grafted controls.

Participants/materials, setting, methods

The 10 animals grafted for 21 days underwent in vivo microdialysis evaluation to investigate direct reactive oxygen species (ROS) kinetics. Analyses of ovarian grafts at all time points and non-grafted controls included immunolabeling for double CD34 (revascularization by host and graft components), immunofluorescence for HIF1α (hypoxia-related response), Nrf2 (oxidative stress-related response) and 8OHdG (oxidative stress-related DNA damage), and gene expression (RT-qPCR) for VEGF-A (neoangiogenesis), SOD2 (antioxidant activity) and Nrf1 (mitochondrial biogenesis).

Main results and the role of chance

ROS peaked sooner in the ASC group (day 2, p &lt; 0.0001) than the OT group (day 10, p = 0.01) after grafting, indicating earlier tissue reperfusion. Total vascularization was stable in the ASC group at all time points, but lower in the OT group 3 days after grafting (p = 0.01) due to a drop in both host and graft vascular components. HIF1α expression, detected mainly in follicles, was significantly lower in primordial follicles in the ASC group than the OT group on days 3 (p = 0.008) and 10 (p = 0.01). VEGF gene expression rose significantly (around 40x) in both groups on day 3 and persisted significantly longer in the ASC group (10 days) than the OT group (3 days) (p = 0.04), emphasizing the role of ASCs as enhancers of proangiogenic factors. There was no upturn in the oxidative stress-related response (Nrf2 pathway) nor DNA damage (8OHdG) to follicles in any of the grafted groups over time, while a modest increase in both markers was observed only in the stroma after 21 days. Neither was there any major increase in SOD2 and Nrf1 gene expression, suggesting no significant activation of the Nrf2 pathway for cytoprotection from oxidative stress.

Limitations, reasons for caution

Although Nrf2 signaling activation was detected in human granulosa cell cultures in increasing ROS concentrations, our findings did not confirm its role in tissue damage modulation after ovarian tissue transplantation. Further studies may evidence the involvement of other pathways that modulate oxidative stress after transplantation.

Wider implications of the findings

The role of ASCs in protecting the follicle pool appears to be related to a decrease in hypoxia and faster ovarian graft revascularization and reperfusion, sustained by an increase in VEGF for a longer period after grafting. There was no evidence of oxidative stress-related damage, irrespective of the transplantation strategy.

Trial registration number

 

P–439 Carbohydrate metabolism profile during oocyte final maturation reveals culture induced aberrations in in vitro grown and matured mouse antral follicles

Study question

Are there significant differences in carbohydrate metabolism trends between in vivo and in vitro grown mouse antral follicles during oocyte final maturation?

Summary answer

Glucose metabolism characterization during GV to MII transition revealed altered metabolic patterns mainly in cumulus cells of in vitro grown and matured mouse antral follicles.

What is known already

For some cancer patients fertility restoration is dependent on using efficient in vitro follicle culture systems. As human donor ovarian tissue available for research is limited, establishing such culture systems relies on data generated from animal models. The culture system previously developed in our laboratory supports in vitro growth of mouse preantral follicles with good oocyte maturation rates but lower developmental competence compared to in vivo grown oocytes. Tracking and comparing the metabolic changes after meiotic maturation in in vitro and in vivo follicles could serve as a screening tool for improving culture conditions and identifying metabolic quality markers.

Study design, size, duration

Mouse secondary follicle culture was performed. In vitro grown oocytes, their corresponding cumulus (CC) and granulosa cells (GC) were collected from antral follicles, at germinal vesicle stage (GV) on day 9, and at metaphase 2 (MII) on day 10, after hCG/EGF stimulation. In vivo age-matched controls were obtained after intraperitoneal injections with eCG for GV, or with eCG and hCG for MII. In vivo GC after ovulation were not included.

Participants/materials, setting, methods

Glucose metabolism trends were compared during final maturation between in vitro grown antral follicles and their in vivo controls. Follicles that failed to resume meiosis in vitro were also included.

Enzymatic spectrophotometric assays were used to measure glycolysis, pentose phosphate pathway (PPP), tricarboxylic acid (TCA) cycle, and the antioxidant capacity in individual cell types. Pools of 5 oocytes and corresponding somatic cells were collected, from 3 independent experiments. Unpaired t-test was performed with significance when p &lt; 0.05.

Main results and the role of chance

Important differences were detected between in vivo and in vitro conditions. GV to MII transition in in vivo follicles leads to a metabolic boost in CC as indicated by: i. significant increase in glycolysis, PPP and TCA cycle activity; ii. higher total antioxidant capacity (TAC) (p &lt; 0.05) and small molecule antioxidant capacity (SMAC) (p &lt; 0.01). After ovulation, the only significant change in oocytes was an increase in nicotinamide adenine dinucleotide phosphate (NADP+) level (p &lt; 0.01), possibly due to increased reduced-NADP recycling.

Meiotic maturation triggered no significant differences in any of the metabolic pathways for in vitro grown oocytes. Contrary to their in vivo controls, in vitro CC showed significant upregulations limited to aconitase, lactate dehydrogenase (LDH) and glutathione-s-transferase (GST) activity (p &lt; 0.05). In vitro GC showed increased G6PDH activity (p &lt; 0.05), suggesting PPP upregulation.

Significant differences were detected between in vivo GV follicles and the in vitro failed-to-mature ones. Oocytes from impaired follicles have higher NADP+ levels (p &lt; 0.0001) than their in vivo immature counterparts. CC showed higher phosphofructokinase (PFK), LDH, catalase activity and increased NADP + (p &lt; 0.01), TAC and SMAC (p &lt; 0.05) compared to in vivo GV CCs. GCs from failed-to-mature follicles have significantly higher LDH and superoxide dismutase (SOD) activity than in vivo GV GC (p &lt; 0.05).

Limitations, reasons for caution

The altered metabolic patterns described here in in vitro follicles during oocyte GV to MII transition are probably the cumulative effects of both growth and maturation in vitro.

Wider implications of the findings: We explored extensively and directly, for the first time, several enzymes and metabolites involved in follicle glucose and redox metabolism in different cell types separately. Understanding of the follicle metabolic requirements is essential for the optimization of follicle culture systems and could lead to development of oocyte quality markers.

Trial registration number

Not applicable

P–699 Multi-scale study of the architecture, topography and mechanics of the human ovary from prepuberty to menopause: a blueprint for next-generation bioengineering and diagnosis

Study question

Does the ovarian ECM have a precise and unique biophysical phenotype, specific to each age, from prepuberty to menopause?

Summary answer

Differences between healthy prepubertal, reproductive-age, and menopausal ovarian tissue, unravel and elucidate a unique biophysical phenotype of reproductive-age tissue, bridging biophysics and female fertility.

What is known already

Ovarian engineering has recently emerged to respond to patient needs and offer reliable models for basic research. It has relied on synthetic and natural biomaterials and microfluidics. However, these techniques were designed based on knowledge acquired from 2D cell culture and animal models.

Our lack of information on the human ovary hampers our ability to mimic the main features of this organ, for clinical applications. The complex composition and hierarchical structure of its ECM complicates the design of truly biomimetic constructs, notably: fiber morphology, interstitial and perifollicular fiber orientation, porosity, topography, and viscoelasticity, which all play a role in mechanotransduction.

Study design, size, duration

Ovarian biopsies were taken from prepubertal (mean age [±SD]=7±3 years, n = 21), reproductive age (mean age [±SD]=27±5, n = 26 ) and menopausal (mean age [±SD]=61±6 years, n = 29) patients after obtaining their informed consent. All participating adult subjects were undergoing laparoscopic surgery for benign gynecological diseases not affecting the ovaries. Prepubertal tissue was derived from young cancer patients scheduled for ovarian cortex cryopreservation as a fertility preservation strategy, before being subjected to acute gonadotoxic cancer treatments.

Participants/materials, setting, methods

All samples were cryopreserved by slow freezing and kept frozen until the day of their analysis. Tissues provided from the same patients (n = 5 per age group) were investigated by scanning electron microscopy (SEM) (fiber, pore and topography analyses) and atomic force microscopy (AFM). A larger number of paraffin-fixed biopsies (prepubertal, n = 16, reproductive-age, n = 21, and menopausal, n = 24) obtained from the biobank of St-Luc’s Hospital were used to conduct computed fiber orientation analysis.

Main results and the role of chance

Our results revealed a unique ECM architecture at reproductive age, where fibers of intermediate diameter are assembled into thickest bundles compared to prepubertal and menopausal tissues(p &lt; 0.0001). Indeed, during prepuberty the bundles assemble into a tight network with high number of small pores while reproductive-age ovary gain more porosity(p &lt; 0.0001). However, at menopause tissue pore number and area change significantly(p &lt; 0.001). These pore geometry and distribution changes contribute to diffusion and access of key molecules to/from cells, which can be translated into changes in permeability and molecule selectivity with age. Fiber directionality around follicle borders at preantral stages revealed that before and after puberty, secondary follicles appear to modify their microenvironment arrangement locally compared to follicles at earlier stages of development (p &lt; 0.01), by reorienting the majority of collagen fibers below 50°.This could indicate that follicles at this stage require higher fiber contact and adhesion signaling to complete their development and maturation towards ovulation. AFM evidenced a relatively rigid ovarian tissue at prepuberty, softening significantly at reproductive age, then stiffening considerably upon menopause. These differences(p &lt; 0.01) are not only structure-dependent, but also related to biochemical differences in ECM composition, as previously demonstrated in our follow-up of variations in elastic matrisome components from prepuberty to menopause.

Limitations, reasons for caution

The samples represent single time points from each age group which could present limitations, since following ovary dynamics from prepuberty to menopause in the same patient is not feasible.

Wider implications of the findings: Our study provides the first conclusive proof of a link between ECM biophysics and fertility by comparing different stages of ovarian transformation related to a woman’s reproductive life, which will oriente new strategies for infertility prognoses based on ECM biophysics and may become a blueprint for designing functional engineered ovaries.

Trial registration number

Not applicable

O-179 Safety of ovarian tissue cryopreservation and transplantation in patients with central nervous system cancers

Study question

Is cryopreserved ovarian tissue transplantation safe in patients with central nervous system (CNS) tumors?

Summary answer

Cancer cell contamination was not detected in any ovarian samples from patients with CNS tumors by histological analysis, immunohistochemistry, molecular biology or long-term xenotransplantation.

What is known already

Frequently encountered CNS cancers in childhood include astrocytoma, medulloblastoma, ependymoma, glioblastoma and germinoma. CNS tumors have the capacity for extraneural metastases in 0.5-18% of cases. There are two publications reporting metastases to patients’ ovaries from medulloblastoma.

Study design, size, duration

Prospective experimental study conducted in an academic gynecology research laboratory using frozen-thawed ovarian tissue from 20 patients suffering from 6 types of CNS tumors, including the most common forms mentioned above and primitive neuroectodermal tumors (PNET). Five-month xenotransplantation was performed to severe combined immunodeficient (SCID) mice.

Participants/materials, setting, methods

Cryopreserved ovarian tissue from 20 patients with CNS cancers was thawed and analyzed for minimal disseminated disease and long-term xenografting to immunodeficient mice. The presence of malignant cells was assessed in both cryopreserved and xenografted ovarian tissue using histological analysis, immunohistochemistry for disease-­specific markers (neuron-specific enolase [NSE] and glial fibrillary acidic protein [GFAP]) and reverse transcription droplet digital polymerase chain reaction (RT-ddPCR) for quantification of GFAP gene amplification.

Main results and the role of chance

No malignant cells were detected in frozen-thawed ovarian tissue from any of the patients by histology, immunolabeling for NSE and GFAP, RT-ddPCR for detection of GFAP gene amplification or xenotransplantation to SCID mice. One patient successfully underwent frozen-thawed ovarian tissue transplantation, resulting in the birth of 3 healthy children, but suffered a recurrence of her PNET 6 years after reimplantation and sadly died. Scrupulous analysis of her remaining frozen tissue showed no infiltration by malignant cells, neither after thawing nor long-term xenotransplantation. No relationship was ever established between the patient’s relapsed cancer and reintroduction of her cryopreserved ovarian tissue. The risk of reseeding cancer cells when transplanting ovarian tissue in patients with CNS cancers can therefore be considered low.

Limitations, reasons for caution

The risk of ovarian metastases cannot be completely ruled out for any type of tumor because we cannot analyze the actual fragments that will be reimplanted.

Wider implications of the findings

Our results indicate that the risk of disseminated disease in ovarian tissue from CNS patients is minimal. This is useful information for doctors when counseling women looking to undergo ovarian tissue transplantation.

Trial registration number

Not applicable

P–456 Impact of first-line chemotherapy prior to ovarian tissue cryopreservation on primordial follicle activation and survival in pre-pubertal and young adult patients

Study question

How does chemotherapeutic regimen administered prior to ovarian tissue cryopreservation affect the signaling pathways regulating ovarian reserve and follicular survival in pre-pubertal and adult patients?

Summary answer

Chemotherapy induces key signaling processes of follicle activation and increases apoptosis in quiescent follicle. However, damages were different according to the age of the patient.

What is known already

Therapeutic regimen can damage the ovarian reserve leading to infertility of cancer survivors. Among fertility preservation options, cortical tissue banking appears to be an attractive alternative for patients who cannot delay their treatment or have already started chemotherapy. Though previous studies showed that first-line chemotherapy may induce follicular damages, the impact on follicle activation signaling pathways in human remains poorly understood. Deciphering the signaling modifications under chemotherapy is critical to have a better understanding of the follicle depletion process. Moreover, only few studies on cryopreserved tissue were conducted in children whereas follicle distribution differs compared to post-pubertal women.

Study design, size, duration

Cryopreserved ovarian tissue from young adult (16–27 years old, n = 6) and pre-pubertal (3–10 years old, n = 6) cancer patients were used as model. Fragments were thawed and cultured for 24 hours after size homogenization (4x2x0.5 mm). Patients who received chemotherapy before ovarian tissue cryopreservation were compared to non-exposed patients. PI3K/AKT/mTOR and Hippo pathways, as well as follicles and stroma survival, were assessed among the different groups at thawing and after culture.

Participants/materials, setting, methods

The impact of previous chemotherapy exposure on follicle activation, on the PI3K/AKT/mTOR and Hippo pathways was assessed at thawing and after 24 hours of culture by protein analyses (immunostaining and western blot). Histological analyses (follicular counting, immunostaining and TUNEL staining) were performed at the two timepoints to assess follicle distribution, morphology, stroma structure and apoptosis. Main results and the role of chance: The damage of chemotherapeutic regimen prior to cryopreservation was observed specifically on quiescent follicles after thawing by TUNEL staining in both adult and pre-pubertal patients. Surprisingly, apoptosis occurred more specifically in oocytes of pre-pubertal treated tissue while adult treated patients showed granulosa cells death. After culture, apoptosis was observed in the stroma but healthy follicles were observed in all conditions. Atretic follicles were observed similarly in pre-pubertal and adult cortex previously exposed to chemotherapy while not in the unexposed tissue. Protein analyses showed a higher expression of PI3K and Hippo proteins among all groups at thawing compared to cultured groups while difference was observed between pre-pubertal and adult cortex. At thawing, cortical tissues previously exposed to chemotherapy had a higher expression of phosphorylated forms of AKT and RPS6 compared to untreated groups, irrespective to the age. Moreover, immunostainings showed an oocyte-specific localization of p-AKT while p-RPS6 was more pronounced in the granulosa cells, suggesting an early process of follicle activation.

Limitations, reasons for caution

This study was limited to the evaluation of two major signaling pathways, PI3K/AKT/mTOR and Hippo. Moreover, considering the scarcity and the heterogeneity of our model, the number of patients included in this study is limited and the results should be interpreted with caution.

Wider implications of the findings: Our results highlight the involvement of age and previous chemotherapeutic treatment in the regulation of signaling pathways regulating follicular activation, growth, and survival. Besides sustaining the chemotherapy-induced “burn out effect” theory, it opens perspectives to regulate the deleterious impacts of chemotherapy on follicles though molecular control of the altered pathways.

Trial registration number

Not applicable

Immunodetection and quantification of enzymatic markers in theca cells: the early process of ovarian steroidogenesis†

The association between theca cells (TCs) and granulosa cells is pivotal to steroid biosynthesis in the ovary. During the late secondary follicle stage, TCs form a layer around granulosa cells, after which their steroidogenic function falls under the control of luteinizing hormone (LH) that activates the cAMP signaling pathway via a G protein-coupled receptor. In addition to perilipin-2, a marker for lipid droplets containing esters as substrates for TCs to produce steroidogenic hormones, other essential proteins, like steroidogenic acute regulatory protein (StAR), cytochrome P450 11A1, cytochrome P450c17, 3 beta-hydroxysteroid dehydrogenase/delta 5 -> 4-isomerase type 1, and 3 beta-hydroxysteroid dehydrogenase/delta 5 -> 4-isomerase type 2, play a role in the cascade after luteinizing hormone-choriogonadotropic hormone receptor (LH/CG-R) occupation by LH. The aim of the present study was to assess expression levels and corresponding amounts of LH/CG-R, perilipin-2, and enzymes involved in the steroidogenic pathway of TCs based on follicle stage. Immunohistochemical analysis of each of these proteins was therefore performed on ovarian samples from nine adult women, most (n = 8) with BRCA1 and/or BRCA2 mutations undergoing prophylactic bilateral oophorectomy. Pictures were taken of the theca layer of secondary, small (<3000 μm), and large (>3000 μm) antral follicles and corpora lutea at 100× magnification. ImageJ software was used to analyze the surface area and expression intensity of each protein at each stage, known as the staining index. Overall, our data showed that LH/CG-R, perilipin-2, and StAR expression increased in the course of folliculogenesis and luteinization. Similarly, cytochrome P450 11A1, cytochrome P450c17, 3 beta-hydroxysteroid dehydrogenase/delta 5 -> 4-isomerase type 1, and 3 beta-hydroxysteroid dehydrogenase/delta 5 -> 4-isomerase type 2 expression were substantially elevated in TCs during folliculogenesis, evidenced by their coordinated action in terms of area covered and expression intensity. This study, conducted for the first time on human ovarian tissue, contributes to localizing and quantifying expression of key steroidogenic proteins at both intracellular and tissue levels. These findings may shed new light on pathological conditions involving the human ovary, such as androgen-secreting tumors of the ovary and other disorders associated with ovarian TCs in patients with polycystic ovary syndrome.

Disease-inducing potential of two leukemic cell lines in a xenografting model

PURPOSE

Cryopreserved ovarian tissue transplant restores ovarian function in young cancer patients after gonadotoxic treatment. However, leukemia is associated with increased risk of malignant cell transmission. We aimed to assess the tumor-inducing potential of two different leukemic cell lines when xenografted to immunodeficient mice.

METHODS

Fifty-four female immunodeficient mice were grafted with either 100, 200, 500, 1000, and 10,000 chronic myeloid leukemia in blast crisis (BV-173) cells or relapsed acute lymphoblastic leukemia (RCH-ACV) cells, embedded inside a fibrin scaffold along with 50,000 human ovarian stromal cells. Two mice per cell line received the fibrin matrix without leukemic cells as negative controls. Clinical signs of disease were monitored for 20 weeks. Grafts, liver tissue, and masses were collected for macroscopic analysis and gene expression of BCR-ABL1 and E2A-PBX fusion transcripts present in BV-173 and RCH-ACV respectively.

RESULTS

BV-173 cells: Mice grafted with 100, 200, or 500 cells showed no sign of disease after and were negative for BCR-ABL1 expression. Three of the 5 animals grafted with 1000 cells and all mice with 10,000 cells developed disease and showed BCR-ABL1-positive expression. RCH-ACV cells: Two out of 4 mice grafted with 100 cells developed disease and were E2A-PBX1-positive. All the animals grafted with higher cell doses showed signs of disease and all but one were E2A-PBX1-positive.

CONCLUSION

The present work proves that the disease-inducing potential of BV-173 and RCH-ACV leukemic cells xenografted to SCID mouse peritoneum differs between cell lines, depending on cell number, type, status, and cytogenetic disease profile when ovarian tissue is harvested.

In vitro differentiation of theca cells from ovarian cells isolated from postmenopausal women

STUDY QUESTION

Can human theca cells (TCs) be differentiated in vitro?

SUMMARY ANSWER

It is possible to differentiate human TCs in vitro using a medium supplemented with growth factors and hormones.

WHAT IS KNOWN ALREADY

There are very few studies on the origin of TCs in mammalian ovaries. Precursor TCs have been described in neonatal mice ovaries, which can differentiate into TCs under the influence of factors from oocytes and granulosa cells (GCs). On the other hand, studies in large animal models have reported that stromal cells (SCs) isolated from the cortical ovarian layer can also differentiate into TCs.

STUDY DESIGN, SIZE, DURATION

After obtaining informed consent, ovarian biopsies were taken from eight menopausal women (53-74 years of age) undergoing laparoscopic surgery for gynecologic disease not related to the ovaries. SCs were isolated from the ovarian cortex and in vitro cultured for 8 days in basic medium (BM) (G1), enriched with growth factors, FSH and LH in plastic (G2) or collagen substrate without (G3) or with (G4) a GC line.

PARTICIPANTS/MATERIALS, SETTING, METHODS

To confirm TC differentiation, relative mRNA levels for LH receptor (Lhr), steroidogenic acute regulatory protein (Star), cholesterol side-chain cleavage enzyme (Cyp11a1), cytochrome P450 17A1 (Cyp17a1), hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 1 (Hsd3b1) and hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 2 (Hsd3b2) were assessed. Immunohistochemistry was also performed for their protein detection and a specific marker was identified for TCs (aminopeptidase-N, CD13), as were markers for theca and small luteal cells (dipeptidyl peptidase IV (CD26) and Notch homolog 1, translocation-associated (NOTCH1)). Finally, we analyzed cell ultrastructure before (Day 0) and after in vitro culture (Day 8), and dehydroepiandrosterone (DHEA) and progesterone levels in the medium using transmission electron microscopy (TEM) and ELISA, respectively.

MAIN RESULTS AND THE ROLE OF CHANCE

Results obtained from qPCR showed a significant increase (P < 0.05) in mRNA levels of Lhr in F2 (floating cells in G2) and G4, Cyp17a1 in G1 and F1 (floating cells in G1) and Hsd3b2 in G1, G2, G3 and G4. Immunohistochemistry confirmed expression of each enzyme involved in the steroidogenic pathway at the protein stage. However, apart from G1, all other groups exhibited a significant (P < 0.05) rise in the number of CD13-positive cells. There was also a significant increase (P < 0.05) in NOTCH1-positive cells in G3 and G4. Ultrastructure analyses by TEM showed a distinct difference between groups and also versus Day 0. A linear trend with time revealed a significant gain (q < 0.001) in DHEA concentrations in the medium during the culture period in G1, G2, G3 and G4. It also demonstrated a statistical increase (q < 0.001) in G2, G3 and G4 groups, but G1 remained the same throughout culture in terms of progesterone levels.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Shorter periods of in vitro culture (e.g. 2, 4 and 6 days) could have led to increased concentrations of differentiated TCs in G2, G3 and G4. In addition, a group of cells cultured in BM and accompanied by COV434 cells would be necessary to understand their role in the differentiation process. Finally, while our results demonstrate that TCs can be differentiated in vitro from cells isolated from the cortical layer of postmenopausal ovaries, we do not know if these cells are differentiated from a subpopulation of precursor TCs present in ovarian cortex or ovarian SCs in general. It is therefore necessary to identify specific markers for precursor TCs in human ovaries to understand the origin of these cells.

WIDER IMPLICATIONS OF THE FINDINGS

This is a promising step toward understanding TC ontogenesis in the human ovary. Moreover, in vitro-generated human TCs can be used for studies on drug screening, as well as to understand TC-associated pathologies, such as androgen-secreting tumors and polycystic ovary syndrome.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the Fonds National de la Recherche Scientifique de Belgique (FNRS) (C.A.A. is an FRS-FNRS Research Associate; grant MIS #F4535 16 awarded to C.A.A.; grant 5/4/150/5 awarded to M.M.D.; grant ASP-RE314 awarded to P.A.) and Foundation Against Cancer (grant 2018-042 awarded to A.C.). The authors declare no competing interests.

Spatiotemporal changes in mechanical matrisome components of the human ovary from prepuberty to menopause

STUDY QUESTION

How do elastic matrisome components change during the lifetime of the human ovary?

SUMMARY ANSWER

The deposition and remodeling of mechanical matrisome components (collagen, elastin, elastin microfibril interface-located protein 1 (EMILIN-1), fibrillin-1 and glycosaminoglycans (GAGs)) that play key roles in signaling pathways related to follicle activation and development evolve in an age- and follicle stage-related manner.

WHAT IS KNOWN ALREADY

The mechanobiology of the human ovary and dynamic reciprocity that exists between ovarian cells and their microenvironment is of high importance. Indeed, while the localization of primordial follicles in the collagen-rich ovarian cortex offers a rigid physical environment that supports follicle architecture and probably plays a role in their survival, ovarian extracellular matrix (ECM) stiffness limits follicle expansion and hence oocyte maturation, maintaining follicles in their quiescent state. As growing follicles migrate to the medulla of the ovary, they encounter a softer, more pliant ECM, allowing expansion and development. Thus, changes in the rigidity of the ovarian ECM have a direct effect on follicle behavior. Evidence supporting a role for the physical environment in follicle activation was provided in clinical practice by ovarian tissue fragmentation, which promoted actin polymerization and disrupted ovarian Hippo signaling, leading to increased expression of downstream growth factors, promotion of follicle growth and generation of mature oocytes.

STUDY DESIGN, SIZE, DURATION

We investigated quantitative spatiotemporal changes in collagen, elastin, EMILIN-1, fibrillin-1 and GAGs from prepuberty to menopause, before conducting a closer analysis of the ECM surrounding follicles, from primordial to secondary stages, in both prepubertal and tissue from women of reproductive age. The study included ovarian tissue (cortex) from 68 patients of different ages: prepubertal (n = 16; mean age [±SD]=8 ± 2 years); reproductive (n = 21; mean age [±SD]=27 ± 4 years); menopausal with estrogen-based HRT (n = 7; mean age [±SD]=58 ± 4 years); and menopausal without HRT (n = 24; mean age [±SD]=61 ± 5 years).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Quantitative investigations of collagen and GAG deposition in ovarian tissue throughout a woman's lifetime were conducted by analyzing brightfield images. Characteristic features of collagen fiber content were based on polarized light microscopy, since polarized light changes with fiber thickness. To evaluate the deposition and distribution of elastin, fibrillin-1 and EMILIN-1, multiplex immunofluorescence was used on at least three sections from each patient. Image processing and tailored bioinformatic analysis were applied to enable spatiotemporal quantitative evaluation of elastic system component deposition in the human ovary over its lifetime.

MAIN RESULTS AND THE ROLE OF CHANCE

While collagen levels increased with age, fibrillin-1 and EMILIN-1 declined. Interestingly, collagen and elastin reached their peak in reproductive-age women compared to prepubertal (P < 0.01; P = 0.262) and menopausal subjects with (P = 0.706; P < 0.01) and without (P = 0.987; P = 0.610) HRT, indicating a positive impact of secreted estrogen and hormone treatment on collagen and elastin preservation. Interestingly, HRT appears to affect elastin presence in ovarian tissue, since a significantly higher (P < 0.05) proportion of elastin was detected in biopsies from menopausal women taking HRT compared to those not. Higher GAG levels were found in adult ovaries compared to prepubertal ovaries (P < 0.05), suggesting changes in tissue ultrastructure and elasticity with age. In this context, elevated GAG values are suspected to participate in hampering formation of the fibrillin-1 network (r = -0.2475; P = 0.04687), which explains its decline over time. This decline partially accounts for the decrease in EMILIN-1 (r = 0.4149; P = 0.00059). Closer examination of the ECM surrounding follicles from the primordial to the secondary stage, both before and after puberty, points to high levels of mechanical stress placed on prepubertal follicles compared to the more compliant ECM around reproductive-age follicles, as suggested by the higher collagen levels and lower elastin content detected mainly around primordial (P < 0.0001; P < 0.0001, respectively) and primary (P < 0.0001; P < 0.001, respectively) follicles. Such a stiff niche is nonpermissive to prepubertal follicle activation and growth, and is more inclined to quiescence.

LARGE SCALE DATA

Not applicable.

LIMITATIONS, REASONS FOR CAUTION

The duration and form of administered HRT were not considered when studying the menopausal patient group undergoing treatment. Moreover, we cannot exclude interference from other nongynecological medications taken by the study patients on ovarian ECM properties since there is no information in the literature describing the impact of each medication on the ECM. Finally, since the ECM is by definition a very heterogeneous meshwork of proteins, the use of two-dimensional histology could be a limitation. Single time points on fixed tissues could also present limitations, since following ovary dynamics from prepuberty to menopause in the same patient is not feasible.

WIDER IMPLICATIONS OF THE FINDINGS

From a biomechanical perspective, our study revealed important changes to ECM properties dictating the mechanical features of ovarian tissue, in line with the existing literature. Our findings pave the way for possible therapeutic targets at the ECM level in the context of female fertility and ovarian rejuvenation, such as mechanical stimulation, antifibrotic treatments, and prevention or reversion of elastic ECM degradation. Our study also sheds light on the follicle-specific ECM composition that is dependent on follicle stage and age. These data will prove very useful in designing biomimetic scaffolds and tissue-engineered models like the artificial ovary. Indeed, they emphasize the importance of encapsulating each type of isolated follicle in an appropriate biomaterial that must replicate the corresponding functional perifollicular ECM and respect ovarian tissue heterogeneity in order to guarantee its biomimicry.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the Fonds National de la Recherche Scientifique de Belgique (FNRS) (C.A.A. is an FRS-FNRS research associate; grant 5/4/150/5 awarded to M.M.D.) and the Université Catholique de Louvain (PhD grant 'Coopération au développement' awarded to E.O.). None of the authors have any competing interests to declare.

Assessing and validating housekeeping genes in normal, cancerous, and polycystic human ovaries

PURPOSE

Housekeeping genes (HKGs), reference or endogenous control genes, are vital to normalize mRNA levels between different samples. Since using inappropriate HKGs can lead to unreliable results, selecting the proper ones is critical for gene expression studies. To this end, normal human ovaries, as well as those from patients diagnosed with ovarian endometrioid adenocarcinoma (OEA), ovarian mucinous adenocarcinoma (OMA), ovarian serous papillary carcinoma (OSPC), and polycystic ovary syndrome (PCOS), were used to identify the most suitable housekeeping genes.

METHODS

RNA was isolated from 5 normal human ovaries (52-79 years of age), 9 cancerous ovaries (3 OEA, 3 OMA, 3 OSPC; 49-75 years of age), and 4 PCOS ovaries (18-35 years of age) in women undergoing hysterectomy. cDNA was synthesized using a whole transcriptome kit, and quantitative real-time PCR was performed using TaqMan array 96-well plates containing 32 human endogenous controls in triplicate.

RESULTS

Among 32 HKGs studied, RPS17, RPL37A, PPIA, 18srRNA, B2M, RPLP0, RPLP30, HPRT1, POP4, CDKN1B, and ELF1 were selected as the best reference genes.

CONCLUSIONS

This study confirms recent investigations demonstrating that conventional HKGs, such as GAPDH and beta-actin, are not suitable reference genes for specific pathological conditions, emphasizing the importance of determining the best HKGs on a case-by-case basis and according to tissue type. Our results have identified reliable HKGs for studies of normal human ovaries and those affected by OEA, OMA, OSPC, or PCOS, as well as combined studies of control subjects vs. each cancer or PCOS group.

Adipose tissue-derived stem cells boost vascularization in grafted ovarian tissue by growth factor secretion and differentiation into endothelial cell lineages

Adipose tissue-derived stem cells (ASCs) have multilineage differentiation potential, proangiogenic properties, and the ability to enhance vascularization in xenografted human ovarian tissue. The aim of the present study was to identify the mechanisms behind the proangiogenic effects of ASCs. For this purpose, severe combined immunodeficient (SCID) mice were grafted with frozen-thawed human ovarian tissue. ASCs were labeled by lentiviral transfection for expression of enhanced green fluorescent protein (eGFP), and human ovarian tissue was grafted using a previously described two-step procedure. In the control group, ovarian tissue was transplanted using the standard one-step approach. Samples were collected and analyzed after 7 days. Detection of the eGFP antigen by immunofluorescence showed ASCs surrounding and infiltrating ovarian tissue grafts. Significantly higher vessel density was observed in the ASC group (P = 0.0182 versus control) on Day 7. Co-expression of eGFP, CD34 and CD31 was demonstrated in human vessels, confirming ASC differentiation into human endothelial cell lineages. Increased gene expression of vascular endothelial growth factor (VEGF) was also shown in the ASC group (P = 0.0182 versus control). Immunohistochemistry targeting anti-human VEGF revealed significantly higher expression levels in the ASC group (P = 0.033 versus control), while VEGF and eGFP immunofluorescence showed greater growth factor expression in areas surrounding ASCs. In conclusion, ASCs differentiate into human vessels and promote secretion of VEGF when transplanted together with human ovarian tissue to SCID mouse peritoneum using a two-step ovarian tissue grafting procedure. This is a promising step towards potentially improving ovarian tissue quality and lifespan. Long-term studies should be conducted to investigate ASC safety and efficacy in the context of ovarian tissue transplantation.

Two-step transplantation with adipose tissue-derived stem cells increases follicle survival by enhancing vascularization in xenografted frozen-thawed human ovarian tissue

STUDY QUESTION

Do adipose tissue-derived stem cells (ASCs) enhance vascularization and follicle survival in xenografted ovarian tissue using a two-step transplantation approach?

SUMMARY ANSWER

Higher rates of oxygenation and vascularization of ovarian tissue, as well as increased follicle survival rates, were detected in the early post-grafting period.

WHAT IS KNOWN ALREADY

ASCs have multilineage differentiation potential, proangiogenic properties and enhance vascularization in a peritoneal grafting site. Some studies suggest that using ASCs may improve ovarian tissue quality by enhancing graft angiogenesis.

STUDY DESIGN, SIZE, DURATION

A total of 15 severe combined immunodeficient (SCID) mice were intraperitoneally grafted with frozen-thawed human ovarian tissue (OT) from five different patients. A peritoneal transplantation site had been previously prepared in a first step using either empty fibrin (Fi+OT group [n = 5]) or ASC-loaded fibrin (Fi/ASCs+OT group [n = 5]) for 14 days prior to grafting. Five mice underwent the standard one-step transplantation procedure and served as controls (OT group). Lithium phthalocyanine (LiPc) crystals were inserted into all grafted human ovarian tissue before transplantation. Levels of partial pressure of oxygen (pO2) in grafts were monitored in vivo by electron paramagnetic resonance (EPR) oximetry on Days 3 and 7. Samples for histology and immunohistochemistry (IHC) were collected after euthanizing the mice on Day 7 following EPR. One piece of ovarian tissue per patient was fixed for analysis to serve as non-grafted controls.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Prospective experimental study conducted at the Gynecology Research Unit, Université Catholique de Louvain. All materials were used to perform pO2 measurements (EPR oximetry), histological (haematoxylin and eosin staining), immunohistochemistry (anti-mouse and human double CD34 and anti-human Ki-67) and TUNEL analyses.

MAIN RESULTS AND THE ROLE OF CHANCE

A significant increase in pO2 was observed in all groups between Days 3 and 7 (P < 0.001). A significantly higher pO2 level was observed in the Fi/ASCs+OT group compared to the OT group on Day 7 (P = 0.028). Total CD34-positive vessel area on Day 7 was greater in the Fi/ASCs+OT group than in any other group (vs non-grafted group: P = 0.0014; vs OT group: P = 0.013; vs Fi+OT group: P = 0.018). Primordial follicle survival rates after grafting were higher in the Fi/ASCs+OT group than in the OT (P = 0.0059) or Fi+OT groups (P = 0.0307). TUNEL-positive follicle percentages after grafting were significantly lower in the Fi/ASCs+OT group than in any other grafted tissue (vs OT group: P = 0.045; vs Fi+OT group: P = 0.0268). Percentages of Ki-67-positive primordial follicles were significantly higher in all grafted groups compared to non-grafted tissue controls (P < 0.01).

LIMITATIONS REASONS FOR CAUTION

As demonstrated by our results, the proposed two-step ovarian tissue transplantation procedure using ASCs enhances vascularization in the early post-grafting period, leading to increased follicle survival rates and decreased apoptosis. However, mechanisms involved in the proangiogenic behavior of ASCs remain to be elucidated.

WIDER IMPLICATIONS OF THE FINDINGS

Our results suggest that the proposed transplantation procedure with ASCs is a promising step towards potentially solving the problem of massive follicle loss after ovarian tissue grafting.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the Fonds National de la Recherche Scientifique de Belgique (FNRS-PDR Convention T.0077.14, grant Télévie No. 7.6515.16 F to DDM and grant 5/4/150/5 awarded to MMD and CAA is research associate, FRS-FNRS), Fonds Spéciaux de Recherche, Fondation St Luc, and Foundation Against Cancer, and donations from the Ferrero family.

Further insights into the impact of mouse follicle stage on graft outcome in an artificial ovary environment

STUDY QUESTION

Are mouse preantral follicles differently affected by isolation, encapsulation and/or grafting procedures according to stage?

SUMMARY ANSWER

Isolated secondary follicles showed superior ability to survive and grow after transplantation, which was not related to a particular effect of the isolation and/or grafting procedure, but rather to their own ability to induce neoangiogenesis.

WHAT IS KNOWN ALREADY

Isolated and encapsulated mouse preantral follicles can survive (6-27%) and grow (80-100%) in a fibrin matrix with a low concentration of fibrinogen and thrombin (F12.5/T1) after short-term transplantation.

STUDY DESIGN, SIZE, DURATION

An in vivo experimental model using 20 donor Naval Medical Research Institute (NMRI) mice (6-25 weeks of age) and 14 recipient severe combined immunodeficient (SCID) mice (11-39 weeks of age) was applied. Each NMRI mouse underwent mechanical disruption of both ovaries and isolation of primordial-primary and secondary follicles with ovarian stromal cells, in order to encapsulate them in an F12.5/T1 matrix. Twelve out of 40 fibrin clots were immediately fixed as controls (D0) (10 for histology and 2 for scanning electron microscopy [SEM]) and the others (n = 28) were grafted to the inner part of the peritoneum for 2 (16 fibrin clots) or 7 (12 fibrin clots) days (D2 and D7).

PARTICIPANTS/MATERIALS, SETTING, METHODS

This study involved the participation of the Gynecology Research Unit (Universitè Catholique de Louvain) and the Physiological Sciences Department (University of Brasília). Specific techniques were used to analyze the follicle recovery rate (hematoxylin-eosin staining), vascularization (CD34) and follicle ultrastructure (transmission electron microscopy [TEM] and SEM).

MAIN RESULTS AND THE ROLE OF CHANCE

After follicle isolation and encapsulation, a statistically higher percentage of normal follicles was observed in the secondary group (62%) than in the primordial-primary group (47%). Follicle recovery rates were 34% and 62% for primordial-primary and secondary follicles on D2, respectively, and 12% and 42% on D7, confirming that secondary follicles survive better than primordial-primary follicles after grafting. Concerning vascularization, both follicle stages exhibited similar vascularization to that seen in control mouse ovary on D7, but a significantly higher number of vessels and greater vessel surface area were detected in the secondary follicle group. Despite structural differences in fiber density between fibrin clots and ovarian tissue observed by SEM and TEM, preantral follicles appeared to be well encapsulated in the matrix, also showing a normal ultrastructure after grafting.

LARGE SCALE DATA

Not applicable.

LIMITATIONS, REASONS FOR CAUTION

As demonstrated by our results during the isolation procedure, we encapsulated a significantly higher number of round structures in the primordial-primary group than in the secondary group, which could partially explain the lower recovery rate of early-stage follicles in our previous study. However, it is not excluded that the physical and mechanical properties of the fibrin matrix may also play a role in follicle survival and growth, so further investigations are needed.

WIDER IMPLICATIONS OF THE FINDINGS

This research represents one more key step in the creation of the artificial ovary.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the Fonds National de la Recherche Scientifique de Belgique (FNRS) to C.A. Amorim as a research associate at FRS-FNRS and (grant 5/4/150/5 awarded to M.M. Dolmans), Fonds Spéciaux de Recherche, Fondation St Luc, Foundation Against Cancer, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES-Brazil) (grant #013/14 CAPES/WBI awarded to C.M. Lucci, with F. Paulini receiving a post-doctoral fellowship), and Wallonie-Bruxelles International, and donations from the Ferrero family. None of the authors have any competing interests to declare in relation to the topic.

Evaluation of minimal disseminated disease in cryopreserved ovarian tissue from bone and soft tissue sarcoma patients

STUDY QUESTION

What is the risk of finding malignant cells in cryopreserved ovarian tissue from sarcoma patients?

SUMMARY ANSWER

Minimal disseminated disease (MDD) was not detected in frozen-thawed ovarian tissue from 26 patients by any of the sensitive methods applied.

WHAT IS KNOWN ALREADY

In case of leukemia, the risk of malignant cell transmission through the graft is well known and widely documented. However, for bone cancer, like Ewing sarcoma or osteosarcoma, only a small number of case reports, have been published. These cancers often affect prepubertal girls, in whom ovarian tissue cryopreservation and transplantation is the only option to preserve fertility.

STUDY DESIGN, SIZE, DURATION

The presence of malignant cells in cryopreserved ovarian tissue from patients with bone/soft tissue sarcoma was investigated with disease-specific markers for each patient, using immunohistochemistry (IHC), FISH and real-time quantitative RT-PCR (qPCR), with the original tumor serving as a positive control.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Forty-eight sarcoma patients were enrolled in the study, 12 of whom subsequently died. In each case, tissue from the primary tumor was investigated in order to identify markers (immunohistochemical and/or molecular) to analyze the ovarian tissue case by case. Ovarian tissue from osteosarcoma (n = 15), liposarcoma (n = 1) and undifferentiated sarcoma (n = 5) patients could not be evaluated, as no specific markers were detected by FISH or sensitive IHC in any of their primary tumoral tissue. One patient with Li-Fraumeni syndrome was also excluded from the study. IHC analyses were therefore performed on ovarian tissue from 26 patients and qPCR on 19. The primary tumors involved were Ewing sarcoma family of tumors (n = 14), rhabdomyosarcoma (n = 7), synovial sarcoma (n = 2), clear cell sarcoma (n = 2) and a malignant peripheral nerve sheath tumor (n = 1).

MAIN RESULTS AND THE ROLE OF CHANCE

MDD was not detected in any of the 26 analyzed samples using sensitive techniques in this largest reported series, even from patients who subsequently died and/or those who presented with metastasis (11/26), hence the most aggressive forms of bone cancer. Indeed, anti-CD99 IHC and PCR performed on patients presenting with Ewing sarcoma family of tumors (n = 14) was negative in all cases. In patients with soft tissue sarcoma (n = 12) primitive tumor markers were detected by IHC and were negative in ovarian tissue. PCR could only be performed in 6/12 of these patients, again proving negative.

LIMITATIONS, REASONS FOR CAUTION

Cryopreserved ovarian fragments to be transplanted cannot be tested, so this analysis of malignant cells cannot guarantee that all cryopreserved fragments will not contain any disseminated disease. Moreover, molecular markers are not readily available for all types of tumors.

WIDER IMPLICATIONS OF THE FINDINGS

These results are reassuring regarding the risk of malignant cells in the ovary for transplantation, as the study involves a large series including different types of sarcomas. We believe this will help clinicians in their patient counseling for fertility preservation and restoration.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the Fonds National de la Recherche Scientifique de Belgique-FNRS under Grants Nos 7.4578.14 (Télévie to MS) and 5/4/150/5 to MMD. The authors declare no competing financial interests.

Influence of follicle stage on artificial ovary outcome using fibrin as a matrix

STUDY QUESTION

Do primordial-primary versus secondary follicles embedded inside a fibrin matrix have different capabilities to survive and grow after isolation and transplantation?

SUMMARY ANSWER

Mouse primordial-primary follicles showed a lower recovery rate than secondary follicles, but both were able to grow.

WHAT IS KNOWN ALREADY

Fresh isolated mouse follicles and ovarian stromal cells embedded in a fibrin matrix are capable of surviving and developing after short-term autografting.

STUDY DESIGN, SIZE, DURATION

In vivo experimental model using 11 donor Naval Medical Research Institute (NMRI) mice and 11 recipient severe combined immunodeficiency (SCID) mice. Both ovaries from all NMRI mice were mechanically disrupted and primordial-primary and secondary follicles were isolated with ovarian stromal cells. They were then encapsulated in a fibrin matrix composed of 12.5 mg/ml of fibrinogen (F12.5) and 1 IU/ml of thrombin (T1) (F12.5/T1), and grafted to the inner part of the peritoneum of SCID mice for 2 and 7 days.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This study was conducted at the Gynecology Research Unit, Université Catholique de Louvain. All materials were used to conduct histological (H-E staining) and immunohistochemical (Ki67, TUNEL) analyses.

MAIN RESULTS AND THE ROLE OF CHANCE

Although all grafted fibrin clots were recovered, the follicle recovery rate on day 2 was 16 and 40% for primordial-primary and secondary follicles respectively, while on day 7, it was 6 and 28%. The secondary group showed a significantly higher recovery rate than the primordial-primary group (23%, P-value <0.001). Follicles found in both groups were viable, as demonstrated by live/dead assays, and no difference was observed in the apoptosis rate between groups, as evidenced by TUNEL. Their growth to further stages was confirmed by Ki67 immunostaining.

LIMITATIONS, REASONS FOR CAUTION

As demonstrated by our results, secondary follicles appear to be more likely to survive and develop than primordial-primary follicles in a fibrin matrix after both periods of grafting. These findings may also be attributed to the specific features of the fibrin matrix, which could benefit larger follicles, but not smaller follicles.

WIDER IMPLICATIONS OF THE FINDINGS

This study is essential to understanding possible impairment caused by factors such as the isolation procedure or fibrin matrix composition to the survival and development of different follicle stages. It therefore provides the basis for further investigations with longer periods of grafting.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by grants from the Fonds National de la Recherche Scientifique de Belgique (grant Télévie No. 7.4578.14 and 7.4627.13, grant 5/4/150/5 awarded to Marie-Madeleine Dolmans), Fonds Spéciaux de Recherche, Fondation St Luc, the Foundation Against Cancer, and the Region Wallone (Convention N°6519-OVART) and donations from Mr Pietro Ferrero, Baron Frère and Viscount Philippe de Spoelberch. None of the authors have any competing interests to declare.

Utilization rates and results of long-term embryo cryopreservation before gonadotoxic treatment

PURPOSE

The aim of this study was to evaluate long-term embryo cryopreservation, utilization, and success rate in patients subjected to gonadotoxic treatments in the context of cancer.

METHODS

This is a retrospective study on patients (n = 54) undergoing ovarian stimulation and IVF for fertility preservation between January 1997 and June 2014. Embryos were slow-frozen and stored until the women were cured and able to undergo embryo transfer.

RESULTS

Fifty-four women underwent 66 oocyte pick-up procedures in total, and embryos were obtained from 52 of the 54 patients. Four patients died before their frozen embryos could be thawed. Of the remaining 48, 9 women returned to use their embryos, resulting in 6 pregnancies (66% cumulative pregnancy rate), two of which ended in miscarriage. The live birth rate per patient was thus 44% (4/9). The true come-back rate, calculated after applicable exclusions, was found to be 23%.

CONCLUSION

IVF followed by embryo freezing is a widely established technique for fertility preservation, but little has been published on the outcomes in cancer patients. While we found the number of good-quality embryos to be lower than in a normal population, the cumulative live birth rate was similar to that achieved with fresh embryos in non-cancer patients. The utilization rate of this fertility preservation method can be considered high.

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.

Current achievements and future research directions in ovarian tissue culture, in vitro follicle development and transplantation: implications for fertility preservation

BACKGROUND Female cancer patients are offered 'banking' of gametes before starting fertility-threatening cancer therapy. Transplants of fresh and frozen ovarian tissue between healthy fertile and infertile women have demonstrated the utility of the tissue banked for restoration of endocrine and fertility function. Additional methods, like follicle culture and isolated follicle transplantation, are in development. METHODS Specialist reproductive medicine scientists and clinicians with complementary expertise in ovarian tissue culture and transplantation presented relevant published literature in their field of expertise and also unpublished promising data for discussion. As the major aims were to identify the current gaps prohibiting advancement, to share technical experience and to orient new research, contributors were allowed to provide their opinioned expert views on future research. RESULTS Normal healthy children have been born in cancer survivors after orthotopic transplantation of their cryopreserved ovarian tissue. Longevity of the graft might be optimized by using new vitrification techniques and by promoting rapid revascularization of the graft. For the in vitro culture of follicles, a successive battery of culture methods including the use of defined media, growth factors and three-dimensional extracellular matrix support might overcome growth arrest of the follicles. Molecular methods and immunoassay can evaluate stage of maturation and guide adequate differentiation. Large animals, including non-human primates, are essential working models. CONCLUSIONS Experiments on ovarian tissue from non-human primate models and from consenting fertile and infertile patients benefit from a multidisciplinary approach. The new discipline of oncofertility requires professionalization, multidisciplinarity and mobilization of funding for basic and translational research.

Xenotransplantation of human ovarian tissue to nude mice: comparison between four grafting sites

BACKGROUND

This study was designed to assess the impact of different ovarian tissue transplantation sites on the follicular pool and ovarian tissue integrity after short-term grafting, since there is no consensus in the literature as to the optimal grafting site in experimental models.

METHODS

Frozen-thawed ovarian tissue from eight patients was grafted for 1 or 3 weeks to the peritoneum, inside the ovarian bursa, under the skin and into the muscle of 16 nude mice. Assessment of follicular density and follicle classification was carried out by histological analysis. Proliferative activity was evidenced by immunostaining with anti-Ki-67 antibodies, and fibrotic areas were analyzed by morphometry on histological slides.

RESULTS

One week post-transplantation, the proportion of Ki-67-positive primordial follicles was higher (20-42%) than in controls (1.7%), demonstrating follicular activation in all four sites. Despite this activation, primordial follicles were still found 3 weeks post-grafting, (34.1-66.9% of the follicle population), most of them quiescent, as indicated by the absence of Ki-67 immunostaining. Cryopreservation and grafting resulted in extensive fibrosis in the stroma. This fibrosis was significantly less pronounced in intramuscular (IM) grafts, representing 18.8% of the surface versus 44.7-60.5% for other sites, after 3 weeks of grafting.

CONCLUSIONS

All four grafting sites equally supported early follicular growth and preserved some quiescent follicles after short-term frozen-thawed human ovarian tissue transplantation. The extensive fibrosis observed does not appear to have a major impact on early follicle development, but its long-term effects must be investigated. The graft environment may be implicated in the preservation of the stroma, as suggested by a lower degree of fibrosis in the IM site.

Allograft of ovarian cortex between two genetically non-identical sisters: case report

Aggressive chemotherapy and radiotherapy generally result in the loss of both endocrine and reproductive functions. In 1990, a woman aged 20 years, presenting with beta-thalassemia major, underwent chemotherapy (busulfan and cyclophosphamide) and total body irradiation (TBI) before bone marrow transplantation (BMT), the donor being her 17-year-old HLA-compatible sister. The treatment resulted in premature ovarian failure. In 2006, after excision of ovarian cortical fragments from the HLA-compatible sister, these fragments were immediately sutured to the ovarian medulla of the patient. Both procedures were performed by laparoscopy. Six months after reimplantation, vaginal ultrasonography and hormone concentrations indicated recovery of ovarian secretion and function. From 6 to 11 months, the patient experienced menstrual bleeding and the development of a follicle concomitant with high estradiol levels. Eleven months after reimplantation, two follicles were detected and punctured under vaginal ultrasonographic control. Two mature oocytes were retrieved and inseminated by ICSI. Two embryos (2- and 3-cell) were obtained. Allotransplantation of fresh ovarian tissue was laparoscopically performed between two genetically non-identical sisters. Restoration of ovarian function was achieved after six months. Oocyte retrieval and embryo development were demonstrated.

Restoration of ovarian function after orthotopic (intraovarian and periovarian) transplantation of cryopreserved ovarian tissue in a woman treated by bone marrow transplantation for sickle cell anaemia: Case report

Ovarian function after orthotopic transplantation of cryopreserved ovarian tissue has been restored in women with malignant disease. Here the techniques are adapted for a non-cancer patient. In 1999, right oophorectomy was performed in a 21 year old woman before chemotherapy, prior to bone marrow transplantation. Ovarian cortex was frozen, according to a strict protocol. After thawing, ovarian cortex was reimplanted into the ovary and in a peritoneal window close to the ovary in 2004. Four-and-a-half months after reimplantation, LH, FSH, 17beta-estradiol and progesterone levels, as well as ultrasonography, demonstrated the presence of an ovulatory cycle. After this cycle, the patient experienced two other ovulatory cycles, evidenced by FSH and 17beta-estradiol concentrations, as well as ultrasound demonstration of a follicle. Follicular development was clearly observed in both the intraovarian site (1st and 2nd cycle) and the peritoneal window (3rd cycle). Restoration of endocrine ovarian function occurred after ovarian cortical strips, biopsied and cryopreserved before chemotherapy, were reimplanted into the ovary itself and a periovarian peritoneal window.

Livebirth after orthotopic transplantation of cryopreserved ovarian tissue

BACKGROUND

The lifesaving treatment endured by cancer patients leads, in many women, to early menopause and subsequent infertility. In clinical situations for which chemotherapy needs to be started, ovarian tissue cryopreservation looks to be a promising option to restore fertility. In 1997, biopsy samples of ovarian cortex were taken from a woman with stage IV Hodgkin's lymphoma and cryopreserved before chemotherapy was initiated. After her cancer treatment, the patient had premature ovarian failure.

METHODS

In 2003, after freeze-thawing, orthotopic autotransplantation of ovarian cortical tissue was done by laparoscopy.

FINDINGS

5 months after reimplantation, basal body temperature, menstrual cycles, vaginal ultrasonography, and hormone concentrations indicated recovery of regular ovulatory cycles. Laparoscopy at 5 months confirmed the ultrasonographic data and showed the presence of a follicle at the site of reimplantation, clearly situated outside the ovaries, both of which appeared atrophic. From 5 to 9 months, the patient had menstrual bleeding and development of a follicle or corpus luteum with every cycle. 11 months after reimplantation, human chorionic gonadotrophin concentrations and vaginal echography confirmed a viable intrauterine pregnancy, which has resulted in a livebirth.

INTERPRETATION

We have described a livebirth after orthotopic autotransplantation of cryopreserved ovarian tissue. Our findings suggest that cryopreservation of ovarian tissue should be offered to all young women diagnosed with cancer.