Basal lamina characterization in frozen-thawed and long-term grafted human prepubertal ovarian tissue.

RESEARCH QUESTION: Are there differences in the composition and structure of the basal lamina surrounding follicles in prepubertal versus adult human ovarian tissue? DESIGN: Frozen-thawed human ovarian tissue from six prepubertal and seven adult patients was divided into three fragments in each case: two for non-grafted tissue evaluation and one for long-term xenografting to mice. Collagen IV and laminin expression were investigated by immunohistochemistry before and after grafting. The basal lamina was analysed by transmission electron microscopy on frozen-thawed tissue. RESULTS: In frozen-thawed tissue, collagen IV was significantly less expressed around prepubertal follicles than around adult follicles (primordial, P = 0.02; intermediate/growing follicles, P = 0.03), while laminin was significantly more expressed (primordial, P = 0.03; intermediate, P = 0.01). Collagen IV expression was significantly higher around prepubertal primordial follicles in grafted tissue than in non-grafted tissue, reaching similar levels to those in adult tissue. Ultrastructure analysis showed the basal lamina around follicles in prepubertal frozen-thawed tissue to be rather patchy and thinner than around adult follicles (primordial/intermediate, P = 0.001; primary, P = 0.02). CONCLUSIONS: In frozen-thawed tissue, the basal lamina around prepubertal follicles is less mature than around adult follicles, but it becomes similar in both prepubertal and adult subjects after grafting. Grafting could therefore induce maturation of the basal lamina around prepubertal follicles.

Mitochondrial content, activity, and morphology in prepubertal and adult human ovaries.

PURPOSE: To investigate whether mitochondrial content, activity, and morphology differ in prepubertal versus adult ovarian follicles. METHODS: Ovarian tissue was collected from 7 prepubertal girls (age 1-10 years) and 6 adult women (age 20-35 years). Primordial and primary follicles were isolated from frozen-thawed prepubertal and adult ovarian tissue and their viability was assessed. Mitochondrial content was investigated by TOMM20 immunostaining of prepubertal and adult ovarian tissue, while mitochondrial activity in isolated follicles was analyzed by MitoTracker CM-H2XRos and JC-1. Frozen-thawed ovarian tissue from the same patients was also evaluated by transmission electron microscopy to examine mitochondrial morphology. RESULTS: Higher TOMM20 staining was detected in prepubertal follicles compared to their adult counterparts, indicating the presence of more mitochondria in prepubertal follicles. Analysis of mitochondrial activity by MitoTracker showed higher fluorescence intensity in prepubertal follicles, suggesting that follicles in this group are more active than adult follicles. JC-1 analysis did not reveal any statistically significant difference in the inactive/active ratio between the two groups. Moreover, ultrastructural analysis by TEM detected morphological differences in the shape and cristae of prepubertal mitochondria, probably suggesting a mechanism of response to autophagy. CONCLUSION: Differences in the number, activity, and morphology of mitochondria were reported, suggesting that consequential modifications might occur during puberty, which could be the window of opportunity required by mitochondria to undergo changes needed to reach maturity, and hence the capacity for ovulation and fertilization.

Can frozen-thawed human ovary withstand refreezing-rethawing in the form of cortical strips?

PURPOSE: The aim of this study was to elucidate whether ovarian tissue is able to withstand a double freezing-thawing procedure. METHODS: Human ovarian cortical biopsies from 4 thawed whole ovaries were divided into 4 experimental subgroups: (a) frozen-thawed non-grafted group, (b) frozen-thawed xenografted group, (c) refrozen-rethawed non-grafted group, and (d) refrozen-rethawed xenografted group. Xenografting was performed using 8 severe combined immunodeficient mice for a total duration of 21 days. The following analyses were conducted: classic hematoxylin and eosin staining, Ki67 immunolabeling, transmission electron microscopy, Masson's green trichrome, and double CD34 immunostaining. RESULTS: Morphologically normal preantral follicles were detected in all groups. We observed a dramatic decline of more than 65% in early preantral follicle survival rates after grafting of both frozen-thawed (p < 0.0001) and refrozen-rethawed (p < 0.0001) ovarian tissue. However, mean follicle densities remained comparable between the frozen-thawed and refrozen-rethawed non-grafted groups, as well as both grafted groups. Equivalent proportions of proliferating early preantral follicles were identified in frozen-thawed and refrozen-rethawed samples, whether the tissue was grafted or not. Furthermore, we did not observe any significant difference in atretic follicle rates between any of the four groups, and the ultrastructural quality of follicles appeared unaffected by the refreezing procedure. Similar proportions of fibrosis were noted in the frozen-thawed and refrozen-rethawed groups, irrespective of grafting. Finally, no significant differences were witnessed in terms of vascularization. CONCLUSION: We were able to demonstrate, for the first time, that refrozen-rethawed ovarian tissue has the same functional characteristics as frozen-thawed ovarian tissue.

Role of the PI3K and Hippo pathways in follicle activation after grafting of human ovarian tissue.

PURPOSE: Our aim was to elucidate the mechanisms involved in follicle activation of the ovarian reserve after human ovarian tissue transplantation, with specific focus on the role of the effectors of the PI3K (mTOR and FOXO1) and Hippo (YAP) signaling pathways and whether they are somehow altered. METHODS: Frozen-thawed ovarian tissue was collected from six women (age 25-35 years) undergoing surgery for non-ovarian pathologies and divided into 4 fragments in each case: one for non-grafted controls and three for grafting to immunodeficient mice for 3, 7 and 21 days. The tissue was processed for hematoxylin and eosin staining, immunohistochemistry and immunofluorescence at different timepoints before and after grafting. Activation of the PI3K and Hippo signaling pathways was investigated by analysis of mTOR phosphorylation, FOXO1 cytoplasmic localization and YAP nuclear localization. RESULTS: No change in mTOR levels was observed in primordial follicles post-transplantation, but a significant upturn was recorded in growing follicles compared with primordial follicles, irrespective of grafting time. A higher percentage of primordial follicles was also found with FOXO1 in the cytoplasm after 3 days of transplantation than in non-grafted controls. Finally, a greater proportion of primordial follicles was detected with YAP in the nucleus at all timepoints after grafting. CONCLUSIONS: This study supports the hypothesis that follicle activation may occur as an early event after transplantation, with follicle growth and death both contributing to the burnout phenomenon. This is the first time that the effectors of the PI3K and Hippo pathways have been investigated in grafted human ovarian tissue and their role in burnout documented.

Does the Akt pathway play a role in follicle activation after grafting of human ovarian tissue?

RESEARCH QUESTION: The aim was to elucidate the delay in and mechanisms of follicle activation after ovarian tissue transplantation, with particular emphasis on the role of the Akt signalling pathway. DESIGN: Ovarian tissue was collected from six patients and divided into four fragments in each case: one for control purposes and three for grafting to immunodeficient mice for 3, 7 and 21 days. Follicle density, classification, growth and atresia, and the Akt pathway were analysed. RESULTS: A significant decrease in primordial follicles and significant increase in growing follicles were detected 3 days after transplantation (both P = 0.01). More than 50% of follicles were atretic after 3 days, and a further 50% after 7 days of grafting. Akt phosphorylation was significantly elevated in primordial follicles after 3 days of grafting (P = 0.048). CONCLUSIONS: This study confirms that primordial follicle activation is an early event after transplantation, and significant follicle death also contributes to the burnout effect, eventually resulting in early depletion of the ovarian reserve. Increased Akt phosphorylation on day 3 post-grafting suggests it plays a role in follicle activation and subsequent burnout.

Safety of ovarian tissue transplantation in patients with borderline ovarian tumors.

STUDY QUESTION: Is transplantation of cryopreserved ovarian tissue from patients with borderline ovarian tumors (BOTs) a safe procedure? SUMMARY ANSWER: BOT cells were found in frozen-thawed and xenografted ovarian tissue in 1 of 11 BOT patients. WHAT IS KNOWN ALREADY: The risk of reintroducing malignant cells upon ovarian tissue transplantation has been subject of debate for many years. Reimplantation of cryopreserved ovarian tissue from leukemia patients is unsafe, while results from studies of cryopreserved ovarian tissue from other forms of cancer, such as Hodgkin's lymphoma, are reassuring. STUDY DESIGN, SIZE, DURATION: Prospective experimental study conducted in an academic research unit using ovarian tissue from 11 patients undergoing cryopreservation for BOTs. PARTICIPANTS/MATERIALS, SETTING, METHODS: Histology, immunohistochemistry (IHC) for mucin 1 (MUC1) and cytokeratin 7 (CK7) and molecular analysis by reverse transcription quantitative polymerase chain reaction (RT-qPCR) for CK7 and MUC1 were performed on frozen-thawed ovarian tissue from 11 patients. Long-term (5 months) xenografting of ovarian tissue in immunodeficient mice was performed. The xenografts were analyzed by histology, IHC and RT-qPCR, furthermore IHC for CD10, a marker of endometriosis, was performed on a selected sample. MAIN RESULTS AND THE ROLE OF CHANCE: Analysis by histology, IHC and RT-qPCR indicated 10 of the ovarian tissue samples were negative. Analysis of the xenograft samples indicated nine were negative for malignant cells but in two xenografts glandular lesions were detected by histology. In these two xenografts, CK7 and MUC1 markers were demonstrated by IHC and CK7 expression also by RT-qPCR. A BOT was confirmed in the xenograft in which the original ovarian tissue was positive, while in the other case IHC demonstrated expression of endometriosis marker CD10. LIMITATIONS, REASONS FOR CAUTION: Cryopreserved ovarian fragments cannot be tested before transplantation, therefore the preimplantation analysis cannot guarantee that all cryopreserved fragments will be free of BOT cells. WIDER IMPLICATIONS OF THE FINDINGS: BOT cells can be found in cryopreserved ovarian tissue from BOT patients, therefore preimplantation analysis is an absolute prerequisite. Endometriosis can also be detected in cryopreserved ovarian tissue and caution should also be exercised in this scenario. 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, Télévie Grant 7.4590.16 awarded to Rossella Masciangelo, and Grant 5/4/150/5 awarded to Marie-Madeleine Dolmans), the Fonds Speciaux de Recherche, and the Foundation Against Cancer. None of the authors have any conflicting interests to declare.

To Assess or Not to Assess: Reconsidering Day 3 Embryo Quality in Planned Freeze-All Blastocyst Cycles.

Day 3 embryo quality is a predictor of in vitro fertilization (IVF) success rates in cleavage-stage embryo transfer. However, the association between day 3 embryo quality and clinical outcomes in blastocyst transfer policy is largely unknown. This retrospective study included 1074 frozen-thawed single day 5/6 blastocyst transfers between January 2019 and December 2022. Three groups were assessed depending on whether the transferred blastocyst derived from a top-quality, good-quality, or poor-quality embryo at day 3. The analysis was conducted independently for each blastocyst quality group (top, good, and poor) using multivariable logistic regression. We applied a Factorial Analysis of Mixed Data (FAMD) to reduce the potential collinearity between the covariates used in the model. All the blastocysts included in this study were obtained from the first ICSI freeze-all cycles. The cleavage and blastocysts stages were assessed between 67 ± 0.5 (day 3), 115 ± 0.5 (day 5), and 139 ± 0.5 (day 6) hours post-insemination (hpi), respectively. After adjusting for the day of transfer (day 5 or day 6) and FAMD dimensions, no statistical differences in a ß-HCG, clinical pregnancy, and live birth were observed among the same-quality blastocysts derived from different day 3 embryo quality groups (top = A, good = B, and poor = C). Our findings showed that a day 3 embryo quality assessment may be unnecessary in planned freeze-all blastocyst cycles.

Fertility Preservation as an Option for Women with Genetic Disorders: Insights from a SWOT Analysis on Elective Oocyte Freezing and Preimplantation Genetic Testing.

This paper uses a SWOT (strengths, weaknesses, opportunities, and threats) analysis to overview the option of fertility preservation in women with genetic diseases, who would later use preimplantation genetic testing for monogenic disorders, in order to not transmit their condition. Strengths associated with elective oocyte freezing are ethical considerations, overall maternal and fetal safety, and effectiveness, if performed at <35 years of age. Weaknesses are related to costs and rare but present (<1-3%) risks of maternal complications. Counselling on fertility management aimed at preventing infertility offers a valuable opportunity, the same as it has been in oncological patients' care. The potentially high percentage of women with genetic conditions who would return to use their frozen oocytes also represents an opportunity together with the minimization of the need for egg donation, which has higher obstetrical risks compared to the use of autologous oocytes. Finally, a threat is represented by the potential psychological distress to young women who could never attempt to become pregnant through preimplantation genetic testing, or do it before any decline in their fertility. Potential unknown future long-term health risks for children conceived after egg vitrification/thawing are also a threat, but current knowledge is reassuring. Altogether, early counselling on the option of fertility preservation should thus be incorporated into standard care of all patients with any genetic condition.

Is Ovarian Tissue Transplantation Safe in Patients with Central Nervous System Primitive Neuroectodermal Tumors?

The risk of reseeding malignancy harbored in cryopreserved and transplanted ovarian tissue has been a source of concern. This study aimed to determine the potential relationship between frozen-thawed ovarian tissue transplantation and primary cancer recurrence. Three patients with cerebral primitive neuroectodermal tumors (PNET) were included in this study. One woman gave birth to three healthy babies following reimplantation of her cryopreserved ovarian tissue, but subsequently died due to cancer relapse six years after ovarian tissue transplantation. The second subject died from progressive cancer, while the third is still alive and awaiting reimplantation of her ovarian tissue in due course. Frozen ovarian cortex from all three patients was analyzed and xenotransplanted to immunodeficient mice for five months. Main outcomes were the presence of cancer cells in the thawed and xenografted ovarian tissue at histology, immunostaining (expression of neuron-specific enolase and glial fibrillary acidic protein (GFAP)), and reverse-transcription droplet digital polymerase chain reaction (RT-ddPCR) (levels of enolase 2 and GFAP). In conclusion, no malignant cells were detected in ovarian tissue from patients with PNET, even in those who experienced recurrence of the disease, meaning that the risk of reseeding cancer cells with ovarian tissue transplantation in these patients can be considered low.

Follicle populations and vascularization in ovarian tissue of pediatric patients before and after long-term grafting.

OBJECTIVE: To characterize ovarian tissue from pediatric patients by evaluating development and vascularization in follicle populations and comparing it with adult tissue after xenografting. DESIGN: Prospective experimental study. SETTING: Academic research center. PATIENT(S): Five children (median age 3 years) and seven women (median age 28 years). INTERVENTION(S): Hematoxylin and eosin staining, immunofluorescence, and transmission electron microscopy (TEM) evaluation before and after grafting. MAIN OUTCOME MEASURE(S): Follicle density, morphology, classification, and size, ovarian tissue vascularization, follicle ultrastructure. RESULT(S): Frozen-thawed ovarian tissue was divided into three fragments: nongrafted controls, TEM, and xenografting for 20 weeks. Follicle density was statistically significantly higher in pediatric than adult patients; even though it decreased in both groups after transplantation, it remained higher in pediatric patients. In the pediatric group, quiescent-stage follicles were the majority of the follicle pool before and after grafting, while growing follicles statistically significantly increased in both groups after grafting. Abnormal and atretic follicles were also observed in pediatric tissue and declined with age and after grafting. Pediatric ovarian tissue contained more and larger immature vessels, while mature vessels were larger in adults. The TEM analysis of abnormal pediatric follicles showed loss of shape and vacuolization of the cytoplasm without organelle damage. CONCLUSION(S): Statistically significant differences in follicle density were observed between pediatric and adult patients, but the follicle proportions were similar before and after grafting, with the exception of atretic and abnormal follicles. Pediatric tissue contains more and larger immature vessels than adult tissue, and the posttransplantation revascularization process is accelerated in this group.

Risk of transplanting malignant cells in cryopreserved ovarian tissue.

Improvements in cancer treatments have increased the chances of survival of young cancer patients, but have given rise to other issues, like premature ovarian insufficiency and infertility. Preservation and subsequent restoration of ovarian function in these patients is now possible thanks to ovarian tissue cryopreservation and transplantation. However, safety concerns about the possible presence of cancerous cells in the tissue to be cryopreserved must be addressed. Indeed, reimplantation of malignant cell-contaminated ovarian tissue could potentially lead to recurrence of the primary disease. This review of the existing literature aims to evaluate the risk of reintroducing malignant cells in pathologies that represent the main indications for ovarian tissue cryopreservation. Experimental studies applying molecular analyses as well as xenografting investigation have proved that hematologic and ovarian malignancies are those at greatest risk of ovarian involvement, and hence recurrence upon reimplantation of frozen-thawed ovarian tissue. Preimplantation analysis using highly sensitive techniques and disease-specific markers is therefore vital in these patients to detect minimal disseminate disease.

Timing should no longer be an obstacle to oocyte cryopreservation in patients with cancer.

PURPOSE: Anticancer treatment-related infertility is preventable with oocyte cryopreservation, but this is often not considered a relevant issue, due to lack of knowledge and time. The aim of this study is to prove that adequate organization of an Oncofertility Unit and the use of new protocols for controlled ovarian stimulation (COS) can reduce the time required by the procedure, encouraging consultants and patients to preserve fertility before gonadotoxic treatments. METHODS: A total of 125 patients diagnosed with malignant tumors were referred to the Oncofertility Unit of San Raffaele Hospital: 52 patients between April 2011 and October 2013 and 73 patients between October 2013 and November 2015. The 2 periods differ in office organization and type of COS protocol used. RESULTS: Between the 2 periods, a reduction in the mean number of days required from first counseling to the initiation (6.45 ± 1.058 vs 1.61 ± 0.228) and the end of the COS (17.83 ± 1.227 vs 13.70 ± 0.393) was observed (p<0.0001). No differences exist in the groups between the mean time required to complete COS (11.38 ± 0.360 vs 12.17 ± 0.309; p = 0.11) and mean number of frozen oocytes (8.458 ± 1.060 vs 10.30 ± 0.919; p = 0.22). Furthermore, in the second period, the number of patients who accepted fertility preservation increased (46.15% vs 64.38%; p<0.05). CONCLUSIONS: Renewed organization of the Oncofertility Unit and the newest random-start COS protocol allowed us to shorten the time for oocyte cryopreservation and start anticancer treatment on time.