Detrimental effects of vitrification on integrin genes (α9 and β1) and in vitro fertilization in mouse oocytes

OBJECTIVE

Integrins are known as key molecules that importantly involve in fertilization. This study aimed to evaluate effects of vitrification on fertilization rate and expression of integrin genes, α9 and β1, on mice oocytes in GV and MІІ stages.

MATERIALS AND METHODS

From the ovarian tissue and fallopian tube of NMRI mice, germinal vesicle (GV, n = 200) and metaphase II (MII, n = 200) oocytes were obtained. Then, oocytes were distributed into 4 groups including non-vitrified GV, non-vitrified MII, vitrified GV, and vitrified MII. Cryotop method was used for vitrification and oocytes (for 4 weeks) were kept in liquid nitrogen. After that, by using an inverted microscope, the rate of survived oocytes was assessed. Also, in vitro fertilization (IVF) for oocytes, obtained from in vitro maturated MII and mice ovaries (ovulated MII), was done to assess embryos at differenced stages (2-cells, morula, and hatched). Finally, RT-qPCR was performed to investigate the mRNA expression of integrin genes (α9 and β1).

RESULTS

After vitrification, the rate of survived oocytes, 68.65%for GV and 65.07% % for MII, did not show a remarkable difference related to non-vitrified groups, while the fertilization rate in vitrified groups remarkably decrease compared to non-vitrified groups (p < 0.05). Also, the expression of α9 and β1 genes was significantly altered in vitrified groups when compared to non-vitrified groups (p < 0.05). There was no significant difference in embryo developmental rates for non-vitrified and vitrified groups.

CONCLUSION

Cryotop method for vitrification caused an alternation in oocyte quality by reducing fertilization rate and integrin gene expression.

RNA Transcripts in Human Ovarian Cells: Two-Time Cryopreservation Does Not Affect Developmental Potential

Sometimes, for medical reasons, when a frozen tissue has already thawed, an operation by re-transplantation may be cancelled, and ovarian tissues should be re-frozen for transplantation next time. Research about the repeated cryopreservation of ovarian cells is rarely reported. It has been published that there is no difference in the follicle densities, proportions of proliferation of early preantral follicles, appearance of atretic follicles, or ultrastructural quality of frozen-thawed and re-frozen-rethawed tissue. However, the molecular mechanisms of a repeated cryopreservation effect on the developmental potential of ovarian cells are unknown. The aim of our experiments was to investigate the effect of re-freezing and re-thawing ovarian tissue on gene expression, gene function annotation, and protein-protein interactions. The morphological and biological activity of primordial, primary, and secondary follicles, aimed at using these follicles for the formation of artificial ovaries, was also detected. Second-generation mRNA sequencing technology with a high throughput and accuracy was adopted to determine the different transcriptome profiles in the cells of four groups: one-time cryopreserved (frozen and thawed) cells (Group 1), two-time cryopreserved (re-frozen and re-thawed after first cryopreservation) cells (Group 2), one-time cryopreserved (frozen and thawed) and in vitro cultured cells (Group 3), and two times cryopreserved (re-frozen and re-thawed after first cryopreservation) and in vitro cultured cells (Group 4). Some minor changes in the primordial, primary, and secondary follicles in terms of the morphology and biological activity were detected, and finally, the availability of these follicles for the formation of artificial ovaries was explored. It was established that during cryopreservation, the CEBPB/CYP19A1 pathway may be involved in regulating estrogen activity and CD44 is crucial for the development of ovarian cells. An analysis of gene expression in cryopreserved ovarian cells indicates that two-time (repeated) cryopreservation does not significantly affect the developmental potential of these cells. For medical reasons, when ovarian tissue is thawed but cannot be transplanted, it can be immediately re-frozen again.

Mechanisms of ovarian aging in women: a review

Ovarian aging is a natural and physiological aging process characterized by loss of quantity and quality of oocyte or follicular pool. As it is generally accepted that women are born with a finite follicle pool that will go through constant decline without renewing, which, together with decreased oocyte quality, makes a severe situation for women who is of advanced age but desperate for a healthy baby. The aim of our review was to investigate mechanisms leading to ovarian aging by discussing both extra- and intra- ovarian factors and to identify genetic characteristics of ovarian aging. The mechanisms were identified as both extra-ovarian alternation of hypothalamic-pituitary-ovarian axis and intra-ovarian alternation of ovary itself, including telomere, mitochondria, oxidative stress, DNA damage, protein homeostasis, aneuploidy, apoptosis and autophagy. Moreover, here we reviewed related Genome-wide association studies (GWAS studies) from 2009 to 2021 and next generation sequencing (NGS) studies of primary ovarian insufficiency (POI) in order to describe genetic characteristics of ovarian aging. It is reasonable to wish more reliable anti-aging interventions for ovarian aging as the exploration of mechanisms and genetics being progressing.

IVM Advances for Early Antral Follicle-Enclosed Oocytes Coupling Reproductive Tissue Engineering to Inductive Influences of Human Chorionic Gonadotropin and Ovarian Surface Epithelium Coculture

In vitro maturation (IVM) is not a routine assisted reproductive technology (ART) for oocytes collected from early antral (EA) follicles, a large source of potentially available gametes. Despite substantial improvements in IVM in the past decade, the outcomes remain low for EA-derived oocytes due to their reduced developmental competences. To optimize IVM for ovine EA-derived oocytes, a three-dimensional (3D) scaffold-mediated follicle-enclosed oocytes (FEO) system was compared with a validated cumulus-oocyte complex (COC) protocol. Gonadotropin stimulation (eCG and/or hCG) and/or somatic cell coculture (ovarian vs. extraovarian-cell source) were supplied to both systems. The maturation rate and parthenogenetic activation were significantly improved by combining hCG stimulation with ovarian surface epithelium (OSE) cells coculture exclusively on the FEO system. Based on the data, the paracrine factors released specifically from OSE enhanced the hCG-triggering of oocyte maturation mechanisms by acting through the mural compartment (positive effect on FEO and not on COC) by stimulating the EGFR signaling. Overall, the FEO system performed on a developed reproductive scaffold proved feasible and reliable in promoting a synergic cytoplasmatic and nuclear maturation, offering a novel cultural strategy to widen the availability of mature gametes for ART.

Mitochondrial activity and redox status in oocytes from old mice: The interplay between maternal and postovulatory aging

Maternal aging has been reported to reduce oocyte quality and, in turn, lower the developmental potential of the resulting embryos. Here, we show that maternally aged oocytes display two strikingly different phenotypes: some have normal morphology, whereas others have significantly shrunk cytoplasm. The latter phenotype usually prevails in aged females. Our objective was to characterize both types of maternally aged oocytes and investigate the origins of this diversity. Importantly, our experiments indicate that shrunk maternally aged oocytes are severely compromised in terms of mitochondrial functionality as compared to their young or morphologically normal maternally aged counterparts: they display significantly decreased mitochondrial activity and lower amounts of ROS. In contrast, morphologically normal maternally aged oocytes had the same mitochondrial activity as young ones, while their ROS levels were higher. Surprisingly, the shrunk phenotype was completely absent in maternally aged oocytes that matured in vitro, suggesting that it is not caused inherently by maternal aging, but may be related to other factors, like postovulatory aging. Indeed, an additional culture of in vitro matured young and old oocytes (i.e., in vitro postovulatory aging) significantly decreased their mitochondrial activity and led to cytoplasm shrinkage. In vivo postovulatory aging had a similar effect on oocytes from both young and old females. Finally, we examined the developmental potential of oocytes obtained from aged females. Shrunk (i.e., most likely postovulatory aged) oocytes failed to become fertilized, whereas morphologically normal ones (i.e., most likely not subjected to postovulatory aging) underwent fertilization and subsequent cleavage divisions, although they achieved the 2-cell stage less frequently than morphologically normal oocytes from young females. Importantly, the quality of blastocysts as well as the live birth rate for morphologically normal oocytes from old and young females were similar. In summary, our data clearly indicate that two pools of oocytes present in oviducts of aged females differ significantly in their quality and developmental potential and that the more severely affected phenotype results most likely from a synergistic action of maternal and postovulatory aging.

Effect of pentobarbital as a euthanasia agent on equine in vitro embryo production

Postmortem and pre-euthanasia oocyte retrieval provides the last opportunity to preserve the genetic material in mares. Pentobarbital (PB) is the most common euthanasia agent; however, its effect on the developmental competence of oocytes has not been determined. Here, we evaluated the concentration of PB in equine follicular fluid (FF) and investigated its effect on the developmental competence of oocytes using a bovine IVF model to overcome the low availability of equine oocytes. The concentration of PB was measured by gas-chromatography/mass-spectrometry in FF collected from mare ovaries immediately after euthanasia (n = 10), 24 h post-euthanasia (n = 10), and from the ovaries collected by ovariectomy (negative control; n = 10). The serum concentration of PB was also evaluated as a positive control. PB was detected in all FF samples with an average concentration of 56.5 μg/ml. Next, bovine cumulus-oocyte complexes (COC) were held in holding media with PB for 6 h at 60 μg/ml (H60, n = 196), 164 μg/ml (H164, n = 215) or without PB (control; n = 212). After holding, the oocytes were matured and fertilized in vitro, followed by in vitro culture to the blastocyst stage. The cumulus expansion grade, cleavage rate, blastocyst rate, embryo kinetic rate and the blastocyst cell numbers were compared among the experimental groups of bovine COC. Higher rates of Grade 1 cumulus expansion were found in controls (54%, 32-76%; median, min-max) in comparison to H60 and H164 (24%,11-33% and 13%, 8-44%; P < 0.001). The cleavage rate was higher in the controls than in H164 (64% vs. 44%; P < 0.01). Blastocyst rates (blastocyst/cleaved oocytes) and total cell number were not different among the groups (control 29%, H60 25%, and H164 24%). In a preliminary study, equine oocytes (n = 28) were exposed to PB in vitro for 6 h followed by intracytoplasmic sperm injection (ICSI) and in vitro embryo production. Exposed oocytes showed a numerically lower maturation rate (43% Vs 52%; P > 0.05) in comparison to the laboratory-established rate during the same timepoints. Overall, we showed that PB reaches the FF immediately after euthanasia, exposing oocytes to this drug. This exposure affected cumulus expansion and cleavage rates in a bovine model, suggesting initial damage caused by PB that may not completely impede the formation of embryos, although lower overall embryo numbers might be obtained.

Novel Approaches Used in Ovarian Tissue Transplantation for Fertility Preservation: Focus on Tissue Engineering Approaches and Angiogenesis Capacity

Due to the impact of the modern lifestyle, female infertility has been reduced because of different reasons. For example, in combined chemotherapeutic therapies, a small fraction of cancer survivors has faced different post-complications and side effects such as infertility. Besides, in modern society, delayed age of childbearing has also affected fertility. Nowadays, ovarian tissue cryopreservation and transplantation (OTC/T) is considered one of the appropriate strategies for the restoration of ovarian tissue and bioactivity in patients with the loss of reproductive function. In this regard, several procedures have been considered to improve the efficacy and safety of OTT. Among them, a surgical approach is used to transplant ovaries into the optimal sites, but the existence of ischemic changes and lack of appropriate revascularization can lead to bulk follicular atresia. Besides, the role of OTC/T is limited in women of advanced maternal age undergoing lifesaving chemo-radiation. As a correlate, the development of de novo approaches with efficacious regenerative outcomes is highly welcomed. Tissue engineering shows high therapeutic potentialities to restore fertility in males and females using the combination of biomaterials, cells, and growth factors. Unfortunately, most synthetic and natural materials are at the experimental stage and only the efficacy has been properly evaluated in limited cases. Along with these descriptions, strategies associated with the induction of angiogenesis in transplanted ovaries can diminish the injuries associated with ischemic changes. In this review, the authors tried to summarize recent techniques, especially tissue engineering approaches for improving ovarian function and fertility by focusing on angiogenesis and neovascularization.

Relationship between Amino Acid Metabolism and Bovine In Vitro Follicle Activation and Growth

The amino acid metabolism of bovine follicles during in vitro growth (IVG) was evaluated to identify potential indicators of health during culture. The bovine ovarian cortex was sliced, prepared as strips, and cultured for 6 days. Tissue samples were examined histologically before and after 6 days of culture, and the degree of follicle activation was classified as either high or low based on the number of growing secondary follicles present (high: 7~11; low: 0~1). In a separate experiment, secondary follicles (diameter range: 100~200 μm) were manually isolated and cultured, and their growth was monitored for 6 days. Cultured follicles were classified as growth or degenerate based on diameter change during culture (growth: +60.5~74.1 μm; degenerate: -28~15.2 μm). Free amino acids and their metabolites were measured in the spent culture medium from each group. In cultured ovarian cortical strips, the concentration of α-aminoadipic acid was significantly higher in the low activation group than in the high group (p < 0.05), while those of methionine, lysine, and arginine were higher in the high activation group. In cultured isolated secondary follicles, concentrations of methionine, tyrosine, histidine, and hydroxyproline were higher in the degenerate group (p ≤ 0.05). In conclusion, amino acid metabolism has the potential to serve as an indicator of primordial follicle activation and subsequent growth rate during bovine IVG.

Experiences of Female Childhood Cancer Patients and Survivors Regarding Information and Counselling on Gonadotoxicity Risk and Fertility Preservation at Diagnosis: A Systematic Review

Background: Childhood cancer patients and their families are increasingly offered oncofertility care including information regarding their risk of gonadal damage by paediatric oncologists, fertility counselling by fertility specialists and fertility preservation options. However, experiences regarding oncofertility care are underreported. We aimed to summarize the available evidence of experiences of female childhood cancer patients and survivors regarding oncofertility care. Methods: Manuscripts were systematically identified using the PubMed and Embase database. From, respectively, 1256 and 3857 manuscripts, 7 articles were included and assessed, including risk of bias assessment. Outcome measures included data describing experiences of female childhood cancer patients and survivors, regarding fertility information, counselling and/or preservation. Results: Female patients and survivors are variably satisfied with fertility information, report challenges in communication with healthcare professionals and prefer to receive general information at diagnosis and detailed fertility information later. Regrets after fertility counselling are underreported, but are associated with refusing fertility preservation. Lastly, regardless of counselling, female patients and survivors report fertility concerns about their future children’s health and effect on relationships. Conclusion: Currently, the satisfaction with oncofertility care varies and female patients or survivors report regrets and concerns regardless of receiving fertility information or counselling. These results may help to improve the content of fertility information, communication skills of healthcare professionals and timing of counselling.

The Mechanisms of BDNF Promoting the Proliferation of Porcine Follicular Granulosa Cells: Role of miR-127 and Involvement of the MAPK-ERK1/2 Pathway

As a member of the neurotrophic family, brain-derived neurotrophic factor (BDNF) provides a key link in the physiological process of mammalian ovarian follicle development, in addition to its functions in the nervous system. The emphasis of this study lay in the impact of BDNF on the proliferation of porcine follicular granulosa cells (GCs) in vitro. BDNF and tyrosine kinase B (TrkB, receptor of BDNF) were detected in porcine follicular GCs. Additionally, cell viability significantly increased during the culture of porcine GCs with BDNF (100 ng/mL) in vitro. However, BDNF knockdown in GCs decreased cell viability and S-phase cells proportion-and BDNF simultaneously regulated the expression of genes linked with cell proliferation (CCND1, p21 and Bcl2) and apoptosis (Bax). Then, the results of the receptor blocking experiment showed that BDNF promoted GC proliferation via TrkB. The high-throughput sequencing showed that BDNF also regulated the expression profiles of miRNAs in GCs. The differential expression profiles were obtained by miRNA sequencing after BDNF (100 ng/mL) treatment with GCs. The sequencing results showed that, after BDNF treatment, 72 significant differentially-expressed miRNAs were detected-5 of which were related to cell process and proliferation signaling pathways confirmed by RT-PCR. Furthermore, studies showed that BDNF promoted GCs' proliferation by increasing the expression of CCND1, downregulating miR-127 and activating the ERK1/2 signal pathway. Moreover, BDNF indirectly activated the ERK1/2 signal pathway by downregulating miR-127. In conclusion, BDNF promoted porcine GC proliferation by increasing CCND1 expression, downregulating miR-127 and stimulating the MAPK-ERK1/2 signaling cascade.

Effects of needle puncturing on re-vascularization and follicle survival in xenotransplanted human ovarian tissue

BACKGROUND

Ovarian tissue transplantation can restore fertility in young cancer survivors, however the detrimental loss of follicles following transplantation of cryopreserved ovarian tissue is hampering the efficiency of the procedure. This study investigates whether needle puncturing prior to transplantation can enhance revascularization and improve follicle survival in xenotransplanted human ovarian cortex.

METHODS

Cryopreserved human ovarian cortex pieces (N = 36) from 20 women aged 24-36 years were included. During the thawing process, each piece of tissue was cut in halves; one half serving as the untreated control and the other half was punctured approximately 150-200 times with a 29-gauge needle. The cortex pieces were transplanted subcutaneously to immunodeficient mice for 3, 6 and 10 days (N = 8 patients) and for 4 weeks (N = 12 patients). After 3, 6 and 10 days, revascularization of the ovarian xenografts were assessed using immunohistochemical detection of CD31 and gene expression of angiogenic factors (Vegfα, Angptl4, Ang1, and Ang2), and apoptotic factors (BCL2 and BAX) were performed by qPCR. Follicle density and morphology were evaluated in ovarian xenografts after 4 weeks.

RESULTS

A significant increase in the CD31 positive area in human ovarian xenografts was evident from day 3 to 10, but no significant differences were observed between the needle and control group. The gene expression of Vegfα was consistently higher in the needle group compared to control at all three time points, but not statistically significant. The expression of Ang1 and Ang2 increased significantly from day 3 to day 10 in the control group (p < 0.001, p = 0.0023), however, in the needle group this increase was not observed from day 6 to 10 (Ang2 p = 0.027). The BAX/BCL2 ratio was similar in the needle and control groups. After 4-weeks xenografting, follicle density (follicles/mm³, mean ± SEM) was higher in the needle group (5.18 ± 2.24) compared to control (2.36 ± 0.67) (p = 0.208), and a significant lower percentage of necrotic follicles was found in the needle group (19%) compared to control (36%) (p = 0.045).

CONCLUSIONS

Needle puncturing of human ovarian cortex prior to transplantation had no effect on revascularization of ovarian grafts after 3, 6 and 10 days xenotransplantation. However, needle puncturing did affect angiogenic genes and improved follicle morphology.

In-vivo oogenesis of oogonial and mesenchymal stem cells seeded in transplanted ovarian extracellular matrix

OBJECTIVE (S)

One way to overcome the recurrence of cancer cells following ovarian tissue transplantation is to use decellularized tissues as a scaffold that does not have any cellular components. These cell-free scaffolds can be seeded with different type of stem cells for ovarian restoration.

MATERIALS AND METHODS

OSCs, PMSCs and BMSCs (oogonial, peritoneal and bone marrow mesenchymal stem cells, respectively) were seeded into human decellularized ovarian tissue as 4 groups: Scaffold + OSCs (SO), Scaffold + OSC + PMSCs (SOP), Scaffold + OSC + BMSCs (SOB) and Scaffold + OSC + PMSCs + BMSCs (SOPB). The produced grafts were transplanted into the sub-peritoneal space of ovariectomized NMRI mice as artificial ovary (AO). The expression of Vegf, CD34, Gdf9, Zp3, Ddx4, Amh and Lhr genes in AOs were measured by qRT-PCR. Also, histotechniques were considered to detect the anti GFP, PCNA, VEGF, GDF9, ZP3 and AMH proteins.

RESULTS

H & E staining showed follicle-like structures in all groups; the number of these structures, in the SOP and SOB groups, were the highest. In SO group, differentiation ability to oocyte and granulosa cells was observed. Endothelial, oocyte, germ, and granulosa cell-like cells were specially seen in SOP and angiogenesis capability was more in SOB group. However, angiogenesis ability and differentiation to theca cell-like cells were more often in SOPB group. While none of the groups showed a significant difference in AMH level, estradiol levels were significantly higher in SOPB group.

CONCLUSION

Integration of OSCs + PMSCs and those OSCs + BMSCs were more conducive to oogenesis.

Biomaterials for Testicular Bioengineering: How far have we come and where do we have to go?

Traditional therapeutic interventions aim to restore male fertile potential or preserve sperm viability in severe cases, such as semen cryopreservation, testicular tissue, germ cell transplantation and testicular graft. However, these techniques demonstrate several methodological, clinical, and biological limitations, that impact in their results. In this scenario, reproductive medicine has sought biotechnological alternatives applied for infertility treatment, or to improve gamete preservation and thus increase reproductive rates in vitro and in vivo. One of the main approaches employed is the biomimetic testicular tissue reconstruction, which uses tissue-engineering principles and methodologies. This strategy pursues to mimic the testicular microenvironment, simulating physiological conditions. Such approach allows male gametes maintenance in culture or produce viable grafts that can be transplanted and restore reproductive functions. In this context, the application of several biomaterials have been proposed to be used in artificial biological systems. From synthetic polymers to decellularized matrixes, each biomaterial has advantages and disadvantages regarding its application in cell culture and tissue reconstruction. Therefore, the present review aims to list the progress that has been made and the continued challenges facing testicular regenerative medicine and the preservation of male reproductive capacity, based on the development of tissue bioengineering approaches for testicular tissue microenvironment reconstruction.

Comparative analysis of biochemical, hormonal, and mineral compositions of preovulatory and cystic ovarian follicles in buffalo during the non-breeding season

This study is a comparative analysis of the biochemical, hormonal, and mineral compositions of follicular fluid in preovulatory and cystic follicles of water buffalo (Bubalus bubalis). In total, reproductive tracts from 215 buffalo along with intact ovaries were collected randomly from an abattoir. The incidence of cystic conditions found in this study was 3.72% (8/215), involving the right ovary in 62.5% of instances and the left ovary in 37.5% of instances during the non-breeding season. Follicular fluid was aspirated from preovulatory follicles (12-15 mm diameter, oestrogen-active, follicular phase or stage IV corpus luteum on one of the two ovaries, n = 10) and cystic follicles (at least 20 mm diameter, no corpus luteum on any one of the two ovaries, n = 8). The follicular fluid samples were assayed for biochemical components (uric acid, creatinine, blood urea nitrogen, cholesterol, total protein, glucose, ascorbic acid, and alkaline phosphatase), hormones (progesterone, estradiol, and insulin), and minerals (calcium, magnesium, phosphorus, copper, zinc, and cobalt). Cystic follicles had greater (P < 0.05) concentrations of creatinine, blood urea nitrogen, cholesterol, progesterone, copper, zinc, and cobalt, and lesser (P < 0.05) concentrations of uric acid, glucose, ascorbic acid, estradiol, insulin, calcium, magnesium, and phosphorus compared with preovulatory follicles. These results indicated the marked differences in follicular fluid composition between preovulatory and cystic follicles in buffalo. Some of the changes were indicative of oxidative stress and disturbed steroidogenesis, two important mechanisms shown to be associated with cystic ovarian disease in various species. Further studies are warranted to investigate whether these differences are directly or indirectly involved in the formation of cystic follicles or are mere manifestations of the condition.

Follicular fluid exosomes inhibit BDNF expression and promote the secretion of chemokines in granulosa cells by delivering miR-10b-5p

Ovulation is an inflammatory response. Before ovulation, follicle cells release chemokines to recruit immune cells and promote ovulation. The objective of this study was to investigate whether follicular fluid exosomes promote chemokine secretion by granulosa cells (GCs). Porcine follicular fluid exosomes and follicular GCs were isolated in vitro. GCs were treated with follicular fluid exosomes in vitro and the differential gene expression profiles of the exosome-treated and control groups were obtained by transcriptome sequencing. The results showed that, when compared to the controls, the expression of the chemokines CCL2 and CXCL8 was significantly increased, whereas the expression of brain-derived neurotrophic factor (BDNF) was significantly decreased. The miRNA expression profiles in follicular fluid exosomes were obtained by microRNA sequencing. The results showed that exosomes carried many microRNAs, and that miR-10b-5p carried by exosomes could promote the secretion of CCL2 and CXCL8 by targeting BDNF. In conclusion, the present study demonstrates that exosomes promote the secretion of CCL2 and CXCL8 by granulosa cells through the miR-10b-5p/BDNF axis to promote ovulation.

Resveratrol alleviates doxorubicin-induced damage in mice ovary

While oocytes and embryos cryopreservation can favor some patients with cancer-induced infertility to achieve pregnancy, the development of effective therapeutic strategies to preserve ovarian function during chemotherapy would be a significant advantage. The aim of the present study is to analyze whether Resveratrol treatment (Res) can preserve ovarian function from doxorubicin (Doxo)-induced gonadotoxicity using a mice model of premature ovarian failure. Res (7 and 15 mg/kg) increased the percentage of primary and antral follicles whilst decreasing the percentage of atretic follicles compared to Doxo alone. Res preserved the number of primordial follicles compared with those in the Doxo group but they did not change from those in the control group. Res treatment increased the number of AMH positive follicles compared to Doxo alone. Res increased proliferation index in follicular cells and reduced the DNA damage and apoptosis in preantral and early antral follicles compared to Doxo alone. Additionally, Doxo administration caused a severe endothelial damage and affected microvasculature stability in the ovary. However, Res was able to increase the recruitment of pericytes and smooth muscle cells in the Doxo-treated group. We also found that Res increased the expression of VEGF compared to Doxo alone. By H&E staining, Doxo-treated mice demonstrated endometrial alterations compared to controls, affecting both epithelial and stromal compartments. Nonetheless, Res restored the architecture of uterine tissue. Moreover, we also showed that Res administration is able to maintain antioxidant defenses through the increase of SOD expression in the Doxo-induced POF model. In conclusion, Res administration prior to and during Doxo treatment might serve as a noninvasive and low-cost protocol to preserve ovarian function in female cancer survivors.

Follicular Atresia, Cell Proliferation, and Anti-Mullerian Hormone in Two Neotropical Primates (Aotus nancymae and Sapajus macrocephalus)

This study evaluated the follicular atresia, cell proliferation, and anti-Mullerian hormone action in Aotus nancymae and Sapajus macrocephalus during three sexual phases (follicular, luteal, and gestational). Follicular quantification and immunolocalization of Caspase-3 protein, B-cell lymphoma 2 (BCL-2), proliferating cell nuclear antigen (PCNA), and anti-Mullerian hormone (AMH) were performed. A significant difference in the quantification between preantral and antral follicles, with a progressive decrease in the antrals, was identified. Protein and hormonal markers varied significantly between follicle cell types (A. nancymae p = 0.001; S. macrocephalus, p = 0.002). Immunostaining in the preantral and antral follicles was present in all sexual phases; for Caspase-3, in granulosa cells, oocytes, and stroma; for BCL-2, in granulosa cells, oocytes, and theca; and for PCNA and AMH, in oocytes and granulosa cells. The immunostaining for Caspase-3 was more expressive in the preantral follicles (follicular phase, p < 0.05), while that for BCL-2 and PCNA was more expressive in the antral follicles of the follicular phase. The AMH was more expressive in the primary and antral follicles of nonpregnant females, in both the follicular and luteal phases. Our results contribute to understanding the ovarian follicular selection, recruitment, and degeneration of these species.

An evaluation of the effects on the ovaries of hyperbaric oxygen therapy in a rat model of premature ovarian failure created with cyclophosphamide

Objective

To evaluate hyperbaric oxygen therapy (HBO) based on ovarian histology, total antioxidant status (TAS), total oxidant status (TOS), and anti-müllerian hormone (AMH), in the ovarian insufiency (POI) model created with cyclophosphamide (CYP).

Materials and Methods

The rats were separated into 3 groups of the control group (n=6), the CYP group (n=6), and the CYP+HBO group (n=6). The rats in the CYP group and the CYP+HBO group were injected intraperitoneally with 200 mg/kg CYP on day 1, followed by 8 mg/kg/day for 14 days to create POI. From the 15^th day onwards, the rats in the CYP+HBO group were placed in a hyperbaric cabin and exposed to 100% oxygen at 2.4 atm pressure for one h, and were then returned to their cages at the end of the hour.

Results

A statistically significant decrease was determined in the primordial and primary follicle counts in the CYP group compared with the control group (p<0.05). In the CYP+HBO group, a statistically significant increase was determined in the primordial and primary follicle counts (p<0.05). The serum AMH levels were seen to be significantly decreased in the CYP group compared with both the control group and the CYP+HBO groups. The HBO was seen to decrease TOS and increase TAS.

Conclusion

HBO could be an alternative treatment to minimize the effect of ovarian follicle loss caused by CYP, which is used for treating tumors that commonly occur in young females of reproductive age.

Population Dynamics, Plasma Cytokines and Platelet Centrifugation: Technical and Sociodemographic Aspects of 'Ovarian Rejuvenation'

While advanced reproductive technologies have attained remarkable increases in sophistication, success, and availability since the 1980s, clinicians always meet a therapeutic impasse when the ovarian reserve reaches exhaustion. Irrespective of fertility aspirations, the decline in and eventual collapse of ovarian estrogen output means that menopause arrives with tremendous physiologic changes and reduced overall productivity. Because more women are gaining in longevity or delaying the age at pregnancy, the number of affected patients has never been larger. As concerns regarding standard hormone replacement therapy and the limitations of IVF are confronted, a workable path to enable primordial germ cell recruitment and de novo oocyte development would be welcome. Proof-of-concept case reports and clinical studies on autologous activated platelet-rich plasma (PRP) or its condensed cytokine derivatives suggest a way to facilitate these goals. However, ovarian PRP faces vexing challenges that place 'ovarian rejuvenation' under caution as it enters this therapeutic space. Here, we review key features of experimental human ovarian stem cell isolation/handling and reaffirm the need to harmonize laboratory protocols. Recognizing the regenerative science borrowed from other disciplines, specimen centrifugation, platelet processing, and condensed plasma cytokine enrichment are highlighted here. As the refinement of this rejuvenation approach would promise to reprogram adult ovarian physiology, the disruption of established treatment paradigms for infertility, menopause, and perhaps overall women's health seems likely. Emerging roles in reproductive biology and clinical practice are thus placed in a broader social and demographic context.

Current Trends on Bioengineering Approaches for Ovarian Microenvironment Reconstruction

Ovarian tissue has a unique microarchitecture and a complex cellular and molecular dynamics that are essential for follicular survival and development. Due to this great complexity, several factors may lead to ovarian insufficiency, and therefore to systemic metabolic disorders and female infertility. Techniques currently used in the reproductive clinic such as oocyte cryopreservation or even ovarian tissue transplant, although effective, have several limitations, which impair their wide application. In this scenario, mimetic ovarian tissue reconstruction comes as an innovative alternative to develop new methodologies for germ cells preservation and ovarian functions restoration. The ovarian extracellular matrix (ECM) is crucial for oocyte viability maintenance, once it acts actively in folliculogenesis. One of the key components of ovarian bioengineering is biomaterials application that mimics ECM and provides conditions for cell anchorage, proliferation, and differentiation. Therefore, this review aims at describing ovarian tissue engineering approaches and listing the main limitations of current methods for preservation and reestablishment of ovarian fertility. In addition, we describe the main elements that structure this study field, highlighting the main advances and the challenges to overcome to develop innovative methodologies to be applied in reproductive medicine. Impact Statement This review presents the main advances in the application of tissue bioengineering in the ovarian tissue reconstruction to develop innovative solutions for ovarian fertility reestablishment.

Post-thaw viability of mouse preantral follicles after cryopreservation with cryotube freezing and OPS vitrification procedures

In the field of reproductive science, there is an increased interest in the application of ovarian preantral follicles. Since the ovary contains a great amount of preantral follicles (PAF), the cryopreservation and in vitro culture of such follicles support the fertility preservation of domestic animals with high genetic value, endangered or zoo animals, and women before anticancer therapy. To date, no standard freezing or vitrification protocol is available in human or animals. The aim of the present study was to examine the viability of preantral follicles cryopreserved using freezing or vitrification protocols: cryotube freezing or OPS vitrification.

Prenatal exposure to acrylamide differently affected the sex ratio, aromatase and apoptosis in female adult offspring of two subsequent generations

In the present study, we investigated the effect of acrylamide (ACR) exposure during pregnancy on the ovary of female adult offspring of two subsequent generations. Sixty-day-old Wistar albino female rats were given different doses of ACR (2.5 and 10 mg/kg/day) from day 6 of pregnancy until giving birth. Females from the first generation (AF1) were fed ad libitum, and thereafter, a subgroup was euthanized at 8 weeks of age and ovary samples were obtained. The remaining females were maintained until they reached sexual maturity (50 days old) and then treated in the same way as the previous generation to obtain the second generation of females (AF2). The histopathological examination indicated a high frequency of corpora lutea along with an increased number of antral follicles that reached the selectable stage mainly at a dose of 2.5 mg/kg/day. Interestingly, ACR exposure significantly increased the mRNA levels of CYP19 gene and its corresponding CYP19 protein expression in AF1 females. The TUNEL assay showed a significantly high rate of apoptosis in stromal cells except for dose of 2.5 mg/kg/day. However, in AF2 females, ACR exposure significantly increased the number of degenerating follicles and cysts while the number of growing follicles was reduced. Moreover, in both ACR-treated groups, estradiol-producing enzyme CYP19A gene and its corresponding protein were significantly reduced, and an excessive apoptosis was produced. We concluded that the ovarian condition of AF1 females had considerable similarity to the typical early perimenopausal stage, whereas that of AF2 females was similar to the late perimenopausal stage in women.

Female Reproductive Aging and Oxidative Stress: Mesenchymal Stem Cell Conditioned Medium as a Promising Antioxidant

The recent tendency to delay pregnancy has increased the incidence of age-related infertility, as female reproductive competence decreases with aging. Along with aging, a lowered capacity of antioxidant defense causes a loss of normal function in the ovaries and uterus due to oxidative damage. Therefore, advancements have been made in assisted reproduction to resolve infertility caused by reproductive aging and oxidative stress, following an emphasis on their use. The application of mesenchymal stem cells (MSCs) with intensive antioxidative properties has been extensively validated as a regenerative therapy, and proceeding from original cell therapy, the therapeutic effects of stem cell conditioned medium (CM) containing paracrine factors secreted during cell culture have been reported to be as effective as that of direct treatment of source cells. In this review, we summarized the current understanding of female reproductive aging and oxidative stress and present MSC-CM, which could be developed as a promising antioxidant intervention for assisted reproductive technology.

Determination of the appropriate concentration of sodium alginate used for in vitro culture of cat preantral follicles in a serum-free medium containing FSH, EGF and IGF-I

Culture of domestic cat preantral follicles can be a suitable technology to assist oocyte conservation strategies in the family Felidae. This research was aimed to comparatively analyse cat preantral follicular development of follicles directly seeded on growth surface or encapsulated in 0.5 or 1% of sodium alginate in a serum-free medium containing FSH, EGF and IGF-I. Preantral follicles were isolated from cat ovarian cortical tissue after ovariectomy. Alginate was dissolved at 0.5 or 1% in PBS. Follicles, 4 per well, with 0% (G-0%), 0.5% (G-0.5%) or 1% (G-1%) of sodium alginate were cultured in M199 with FSH (100 ng/mL), EGF (100 ng/mL) and IGF-I (100 ng/mL) for 7 days at 37°C, 5% CO₂ and 99% humidity. Culture medium was replaced every 48 h and samples were stored at -20°C until ELISA of steroid hormones. Morphometric evaluation of follicles was performed every 24 h. G-0% follicles showed granulosa cell migration away from the oocyte and disrupted morphology, whereby they reached apparently larger diameters (203.70 ± 5.82 μm; p < .05) than G-0.5% and G-1% follicles (157.89 ± 8.47 μm and 95.23 ± 1.67 μm, respectively) which maintained three-dimensional organization, being larger in G-0.5% than in G-1% (p < .05). G-0.5% follicles attained the multi-layer preantral follicle stage on day 7 of culture, whereas G-1% follicles underwent progressive atresia. On day 6, steroid concentrations were higher (p < .05) in G-0% than in G-1%: 60 ± 19 vs 0.88 ± 0.32 pg/mL oestradiol; 2.6 ± 0.84 vs 0.04 ± 0.02 ng/mL progesterone; 1.3 ± 0.22 vs 0.61 ± 0.04 ng/mL testosterone and 1.6 ± 0.54 vs 0.22 ± 0.07 ng/mL androstenedione respectively. Steroid concentrations in G-0.5% were comprised between those of G-0% and G-1% (p > .05). In conclusion, two-layer cat preantral follicles encapsulated in 0.5% alginate cultured in medium containing FSH, EGF and IGF-I can develop up to the multi-layer preantral stage in 7 days of culture, whereas follicles directly seeded on growth surface or encapsulated in 1% alginate lost their three-dimensional organization, and experienced regression with compromised steroidogenesis, respectively.

Characterization of Oogonial Stem Cells in Adult Mouse Ovaries with Age and Comparison to In Silico Data on Human Ovarian Aging

Many adult somatic stem cell lineages are comprised of subpopulations that differ in gene expression, mitotic activity, and differentiation status. In this study, we explored if cellular heterogeneity also exists within oogonial stem cells (OSCs), and how chronological aging impacts OSCs. In OSCs isolated from mouse ovaries by flow cytometry and established in culture, we identified subpopulations of OSCs that could be separated based on differential expression of stage-specific embryonic antigen 1 (SSEA1) and cluster of differentiation 61 (CD61). Levels of aldehyde dehydrogenase (ALDH) activity were inversely related to OSC differentiation, whereas commitment of OSCs to differentiation through transcriptional activation of stimulated by retinoic acid gene 8 was marked by a decline in ALDH activity and in SSEA1 expression. Analysis of OSCs freshly isolated from ovaries of mice between 3 and 20 months of age revealed that these subpopulations were present and persisted throughout adult life. However, expression of developmental pluripotency associated 3 (Dppa3), an epigenetic modifier that promotes OSC differentiation into oocytes, was lost as the mice transitioned from a time of reproductive compromise (10 months) to reproductive failure (15 months). Further analysis showed that OSCs from aged females could be established in culture, and that once established the cultured cells reactivated Dppa3 expression and the capacity for oogenesis. Analysis of single-nucleus RNA sequence data sets generated from ovaries of women in their 20s versus those in their late 40s to early 50s showed that the frequency of DPPA3-expressing cells decreased with advancing age, and this was paralleled by reduced expression of several key meiotic differentiation genes. These data support the existence of OSC subpopulations that differ in gene expression profiles and differentiation status. In addition, an age-related decrease in Dppa3/DPPA3 expression, which is conserved between mice and humans, may play a role in loss of the ability of OSCs to maintain oogenesis with age.

Summary of the ISFP congress, Brussels, 10-12 November, 2022

The 7th International Congress of the ISFP was held in Brussels in November 2022. Hundreds of attendees from all over the world had the rare opportunity to hear the most distinguished leaders discuss and debate the latest advances in the field. Participants were also able to attend workshops under the guidance of skilled practitioners. Numerous topics were considered, including a recap on fertility preservation approaches in cancer and benign pathologies and a section on male factor infertility. Other aspects covered were in vitro maturation and poor responders, the impact of chemotherapy on the ovary, and future perspectives. Participants had the chance to listen to a symposium on fertility preservation techniques, and finally, a keynote lecture on fertility preservation in gynecological cancers brought this prominent and highly influential event to a close.

Pediatric oncofertility care in limited versus optimum resource settings: results from 39 surveyed centers in Repro-Can-OPEN Study Part I & II

PURPOSE

As a secondary report to elucidate the diverse spectrum of oncofertility practices for childhood cancer around the globe, we present and discuss the comparisons of oncofertility practices for childhood cancer in limited versus optimum resource settings based on data collected in the Repro-Can-OPEN Study Part I & II.

METHODS

We surveyed 39 oncofertility centers including 14 in limited resource settings from Africa, Asia, and Latin America (Repro-Can-OPEN Study Part I), and 25 in optimum resource settings from the USA, Europe, Australia, and Japan (Repro-Can-OPEN Study Part II). Survey questions covered the availability of fertility preservation and restoration options offered in case of childhood cancer as well as their degree of utilization.

RESULTS

In the Repro-Can-OPEN Study Part I & II, responses for childhood cancer and calculated oncofertility scores showed the following characteristics: (1) higher oncofertility scores in optimum resource settings than in limited resource settings for ovarian and testicular tissue cryopreservation; (2) frequent utilization of gonadal shielding, fractionation of anticancer therapy, oophoropexy, and GnRH analogs; (3) promising utilization of oocyte in vitro maturation (IVM); and (4) rare utilization of neoadjuvant cytoprotective pharmacotherapy, artificial ovary, in vitro spermatogenesis, and stem cells reproductive technology as they are still in preclinical or early clinical research settings.

CONCLUSIONS

Based on Repro-Can-OPEN Study Part I & II, we presented a plausible oncofertility best practice model to help optimize care for children with cancer in various resource settings. Special ethical concerns should be considered when offering advanced and innovative oncofertility options to children.

Fertility discussions and concerns in childhood cancer survivors, a systematic review for updated practice

PURPOSE

To provide ways to improve the clinical practice of fertility preservation (FP) for children, adolescents, and young adults (AYA) with cancer.

DESIGN

A systematic research of online databases was undertaken in March 2020 following the PRISMA criteria, including Medline and Web of Science.

RESULTS

Fifty-nine articles were included. Surveys, interviews, and focus groups were used to collect data from patients, parents, and health care providers (HCPs). Four themes worth exploring emerged: (a) what do patients and professionals think of and know about FP? (b) what makes the fertility discussion happen or not? (c) what, retrospectively, led to FP being pursued or not? and (d) how do patients and HCPs feel about fertility issues?

CONCLUSION

A minority of AYAs preserve their fertility (banking assay for 45% of boys and 23% of girls). Yet fertility concerns have a significant impact on the quality of life of young cancer survivors. Although recommendations and guidelines regarding FP are available internationally, there are no specific guidelines as to how to conduct fertility counseling for children and adolescents. Some barriers are not removable, such as a poor prognosis of an obvious severe disease, time constraints for starting treatment, and cultural and religious beliefs. In response to aspects hindering patients and families to be receptive to any discussion at the time of diagnosis, psychological support could reduce the level of emotional distress and help restore a degree of open-mindedness to open a window for discussion. Moreover, as the lack of knowledge of professionals about fertility is frequently pointed out as a limiting factor for fertility discussion, reinforcing professional training regarding FP could be proposed to promote fertility discussion and eventually referral for FP.

Spatio-temporal remodelling of the composition and architecture of the human ovarian cortical extracellular matrix during in vitro culture

STUDY QUESTION

How does in vitro culture alter the human ovarian cortical extracellular matrix (ECM) network structure?

SUMMARY ANSWER

The ECM composition and architecture vary in the different layers of the ovarian cortex and are remodelled during in vitro culture.

WHAT IS KNOWN ALREADY

The ovarian ECM is the scaffold within which follicles and stromal cells are organized. Its composition and structural properties constantly evolve to accommodate follicle development and expansion. Tissue preparation for culture of primordial follicles within the native ECM involves mechanical loosening; this induces undefined modifications in the ECM network and alters cell-cell contact, leading to spontaneous follicle activation.

STUDY DESIGN, SIZE, DURATION

Fresh ovarian cortical biopsies were obtained from six women aged 28-38 years (mean ± SD: 32.7 ± 4.1 years) at elective caesarean section. Biopsies were cut into fragments of ∼4 × 1 × 1 mm and cultured for 0, 2, 4, or 6 days (D).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Primordial follicle activation, stromal cell density, and ECM-related protein (collagen, elastin, fibronectin, laminin) positive area in the entire cortex were quantified at each time point using histological and immunohistological analysis. Collagen and elastin content, collagen fibre characteristics, and follicle distribution within the tissue were further quantified within each layer of the human ovarian cortex, namely the outer cortex, the mid-cortex, and the cortex-medulla junction regions.

MAIN RESULTS AND THE ROLE OF CHANCE

Primordial follicle activation occurred concomitantly with a loosening of the ovarian cortex during culture, characterized by an early decrease in stromal cell density from 3.6 ± 0.2 × 106 at day 0 (D0) to 2.8 ± 0.1 × 106 cells/mm3 at D2 (P = 0.033) and a dynamic remodelling of the ECM. Notably, collagen content gradually fell from 55.5 ± 1.7% positive area at D0 to 42.3 ± 1.1% at D6 (P = 0.001), while elastin increased from 1.1 ± 0.2% at D0 to 1.9 ± 0.1% at D6 (P = 0.001). Fibronectin and laminin content remained stable. Moreover, collagen and elastin distribution were uneven throughout the cortex and during culture. Analysis at the sub-region level showed that collagen deposition was maximal in the outer cortex and the lowest in the mid-cortex (69.4 ± 1.2% versus 53.8 ± 0.8% positive area, respectively, P < 0.0001), and cortical collagen staining overall decreased from D0 to D2 (65.2 ± 2.4% versus 60.6 ± 1.8%, P = 0.033) then stabilized. Elastin showed the converse distribution, being most concentrated at the cortex-medulla junction (3.7 ± 0.6% versus 0.9 ± 0.2% in the outer cortex, P < 0.0001), and cortical elastin peaked at D6 compared to D0 (3.1 ± 0.5% versus 1.3 ± 0.2%, P < 0.0001). This was corroborated by a specific signature of the collagen fibre type across the cortex, indicating a distinct phenotype of the ovarian cortical ECM depending on region and culture period that might be responsible for the spatio-temporal and developmental pattern of follicular distribution observed within the cortex.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Ovarian cortical biopsies were obtained from women undergoing caesarean sections. As such, the data obtained may not accurately reflect the ECM distribution and structure of non-pregnant women.

WIDER IMPLICATIONS OF THE FINDINGS

Clarifying the composition and architecture signature of the human ovarian cortical ECM provides a foundation for further exploration of ovarian microenvironments. It is also critical for understanding the ECM-follicle interactions regulating follicle quiescence and awakening, leading to improvements in both in vitro activation and in vitro growth techniques.

STUDY FUNDING/COMPETING INTEREST(S)

Medical Research Council grant MR/R003246/1 and Wellcome Trust Collaborative Award in Science: 215625/Z/19/Z. The authors have no conflicts to declare.

TRIAL REGISTRATION NUMBER

N/A.

MicroRNA-27a-3p targeting Vangl1 and Vangl2 inhibits cell proliferation in mouse granulosa cells

BACKGROUND

Mammalian folliculogenesis is the complex process through which primordial follicles develop into preovulatory follicles. The chief function of ovarian follicle granulosa cells is to play a vital role in the growth, development and atresia of ovarian follicles via gap junctions. Increasing evidence suggests that microRNAs (miRNAs) are essential regulators of granulosa cell apoptosis or proliferation.

METHODS

The expression level of miR-27a-3p, myogenic differentiation (MyoD), Vangl1 and Vangl2 was investigated by Real-time quantitative PCR (RT-qPCR) and Western blot. Luciferase reporter assay, bioinformatics analysis and ChIP-PCR was used to detect the binding sites between miR-27a-3p, transcription factor and target genes. KEGG pathway analyses were performed to reveal the predicted targets of miR-27a-3p. Ethynyl deoxyuridine (EdU) proliferation assay was used to measure cell proliferation.

RESULTS

To explore the underlying mechanisms of the miR-27a-3p function in the development of mouse granulosa cells (mGCs), we screened for the target genes of miR-27a-3p, confirmed its interaction with Vangl1 and Vangl2 and elucidated their roles in mGCs. MiR-27a-3p inhibited the proliferation of mGCs, whereas target genes Vangl1 and Vangl2 had the opposite effect. In addition, the transcription factor MYOD bound to and activated the promoter of miR-27a-3p. MiR-27a-3p suppressed Vangl1 and Vangl2 expression by targeting their 3'-untranslated region (3'-UTR). Furthermore, Vangl1 and Vangl2 suppressed the Wnt pathway by reducing the expression of β-catenin and B-cell lymphoma/leukemia-2 (Bcl-2).

CONCLUSION

These findings indicate a pro-survival mechanism of the MyoD/miR-27a-3p/Vangl1/Vangl2 axis for granulosa cell proliferation and suggest a novel target for the improvement of female fertility.

Ovarian rescue in women with premature ovarian insufficiency: facts and fiction

The ovary has a comparatively short functional lifespan compared with other organs, and genetic and pathological injuries can further shorten its functional life. Thus, preserving ovarian function should be considered in the context of women with threats to ovarian reserve, such as ageing, premature ovarian insufficiency (POI) and diminished ovarian reserve (DOR). Indeed, one-third of women with POI retain resting follicles that can be reactivated to produce competent oocytes, as proved by the in-vitro activation of dormant follicles. This paper discusses mechanisms and clinical data relating to new therapeutic strategies using ovarian fragmentation, stem cells or platelet-rich plasma to regain ovarian function in women of older age (>38 years) or with POI or DOR. Follicle reactivation techniques show promising experimental outcomes and have been successful in some cases, when POI is established or DOR diagnosed; however, there is scarce clinical evidence to warrant their widespread clinical use. Beyond these contexts, also discussed is how new insights into the biological mechanisms governing follicular dynamics and oocyte competence may play a role in reversing ovarian damage, as no technique modifies oocyte quality. Additional studies should focus on increasing follicle number and quality. Finally, there is a small but important subgroup of women lacking residual follicles and requiring oocyte generation from stem cells.

The ovaries of transgender men indicate effects of high dose testosterone on the primordial and early growing follicle pool

Androgens are essential in normal ovarian function and follicle health but hyperandrogenism, as seen in polycystic ovary syndrome, is associated with disordered follicle development. There are few data on the effect of long-term exposure to high levels of testosterone as found in transgender men receiving gender-affirming endocrine therapy. In this study, we investigate the effect of testosterone on the development, morphological health and DNA damage and repair capacity of human ovarian follicles in vivo and their survival in vitro. Whole ovaries were obtained from transgender men (mean age: 27.6 ± 1.7 years; range 20-34 years, n = 8) at oophorectomy taking pre-operative testosterone therapy. This was compared to cortical biopsies from age-matched healthy women obtained at caesarean section (mean age: 31.8±1.5 years; range= 25-35 years, n=8). Cortical tissues were dissected into fragments and either immediately fixed for histological analysis or cultured for 6 days and subsequently fixed. Follicle classification and morphological health were evaluated from histological sections stained with H&E and expression of γH2AX as a marker of DNA damage by IHC. In uncultured tissue, testosterone exposure was associated with reduced follicle growth activation, poor follicle health and increased DNA damage. After 6 days of culture, there was enhanced follicle activation compared to control with further deterioration in morphological health and increased DNA damage. These data indicate that high circulating concentrations of testosterone have effects on the primordial and small-growing follicles of the ovary. These results may have implications for transgender men receiving gender-affirming therapy prior to considering pregnancy or fertility preservation measures.

Transcriptomic screening to identify hub genes and drug signatures for PCOS based on RNA-Seq data in granulosa cells

BACKGROUND

Polycystic ovary syndrome (PCOS) is one of the most incident reproductive diseases, and remains the main cause of female infertility. Granulosa cells play a critical role in normal follicle development and steroid hormones synthesis. In spite of extensive research, no sole medication has been approved by FDA to treat PCOS. This study aimed to investigate the novel therapeutics targets in PCOS, focusing on granulosa cells transcriptome functional analysis with a drug repositioning approach.

METHODS

PCOS microarray and RNA-Seq datasets in granulosa cells were screened and reanalyzed. KEGG pathway enrichment and interaction network analyses were performed and followed by a set of drug signature screening and Poly-pharmacology survey.

RESULTS

545 deregulated genes were identified via filters including p_adj < 0.05 and |log2FC| > 1. Amongst the top 15 KEGG pathways significantly enriched, metabolism of xenobiotics by cytochrome P450, steroid hormone biosynthesis and ovarian steroidogenesis were observed. The Protein-Protein Interaction network identified 18 hub genes amongst this set. Interestingly, most candidate drug signatures have been introduced by databases are either FDA approved or entered into clinical trials, including melatonin, resveratrol and raloxifene. Investigational or experimental introduced drugs obey rules of drug-likeness with almost safe and acceptable ADMET properties. Notably, 21 top target genes of the final drug set were also included in the granulosa significant differentially expressed genes.

CONCLUSION

Results of the current study represent approved, investigational and experimental drug signatures according to the differentially expressed genes in granulosa cells with supported literature reviews. This data might be useful for researchers and clinicians to pave the way for better management of PCOS.

Molecular characterization of extracellular vesicles derived from follicular fluid of women with and without PCOS: integrating analysis of differential miRNAs and proteins reveals vital molecules involving in PCOS

PURPOSE

To elucidate the characterization of extracellular vesicles (EVs) in the follicular fluid-derived extracellular vesicles (FF-EVs) and discover critical molecules and signaling pathways associating with the etiology and pathobiology of PCOS, the differentially expressed miRNAs (DEmiRNAs) and differentially expressed proteins profiles (DEPs) were initially explored and combinedly analyzed.

METHODS

First, the miRNA and protein expression profiles of FF-EVs in PCOS patients and control patients were compared by RNA-sequencing and tandem mass tagging (TMT) proteomic methods. Subsequently, Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes were used to analyze the biological function of target genes of DEmiRNAs and DEPs. Finally, to discover the functional miRNA-target gene-protein interaction pairs involved in PCOS, DEmiRs target gene datasets and DEPs datasets were used integratedly.

RESULTS

A total of 6 DEmiRNAs and 32 DEPs were identified in FF-EVs in patients with PCOS. Bioinformatics analysis revealed that DEmiRNAs target genes are mainly involved in thiamine metabolism, insulin secretion, GnRH, and Apelin signaling pathway, which are closely related to the occurrence of PCOS. DEPs also closely related to hormone metabolism processes such as steroid hormone biosynthesis. In the analysis integrating DEmiRNAs target genes and DEPs, two molecules, GRAMD1B and STPLC2, attracted our attention that are closely associated with cholesterol transport and ceramide biosynthesis, respectively.

CONCLUSION

Dysregulated miRNAs and proteins in FF-EVs, mainly involving in hormone metabolism, insulin secretion, neurotransmitters regulation, adipokine expression, and secretion, may be closely related to PCOS. The effects of GRAMD1B and STPLC2 on PCOS deserve further study.

Age-related methylation changes in the human sperm epigenome

Advanced paternal age is associated with increased risks for reproductive and offspring medical problems. Accumulating evidence suggests age-related changes in the sperm epigenome as one underlying mechanism. Using reduced representation bisulfite sequencing on 73 sperm samples of males attending a fertility center, we identified 1,162 (74%) regions which were significantly (FDR-adjusted) hypomethylated and 403 regions (26%) being hypermethylated with age. There were no significant correlations with paternal BMI, semen quality, or ART outcome. The majority (1,152 of 1,565; 74%) of age-related differentially methylated regions (ageDMRs) were located within genic regions, including 1,002 genes with symbols. Hypomethylated ageDMRs were closer to transcription start sites than hypermethylated DMRs, half of which reside in gene-distal regions. In this and conceptually related genome-wide studies, so far 2,355 genes have been reported with significant sperm ageDMRs, however most (90%) of them in only one study. The 241 genes which have been replicated at least once showed significant functional enrichments in 41 biological processes associated with development and the nervous system and in 10 cellular components associated with synapses and neurons. This supports the hypothesis that paternal age effects on the sperm methylome affect offspring behaviour and neurodevelopment. It is interesting to note that sperm ageDMRs were not randomly distributed throughout the human genome; chromosome 19 showed a highly significant twofold enrichment with sperm ageDMRs. Although the high gene density and CpG content have been conserved, the orthologous marmoset chromosome 22 did not appear to exhibit an increased regulatory potential by age-related DNA methylation changes.

Biobanking and use of gonadal tissues - a promising strategy for conserving wildlife from the Caatinga biome

Biological Resource Banks (BRB) or Genetic Resource Banks (GRB) are critical tools for the conservation of animal biodiversity. According to the International Union for Conservation of Nature, more than 38,500 species are threatened with extinction, out of a total of 138,300 surveyed species. These banks are repositories of biological samples and data recovered and preserved for the long term by zoos, universities, research centers and other conservation organizations. In recent years, BRB have increasingly included ovarian and testicular tissues as additional options to rescue and propagate wild species, especially those at risk of extinction. After in vitro culture or grafting, gonadal tissues are potential sources of matured gametes that can be used for Assisted Reproduction Technologies while informing about gametogenesis or mechanisms involved in infertility. It therefore is crucial to properly recover, cryopreserve, and culture these tissues using species-specific protocols. Developing BRBs is currently one of the strategies to preserve species from the Caatinga biome - an exclusively Brazilian biome with a rich wild fauna that suffers from anthropogenic activities. Among wild species from this biome, studies have been primarily conducted in collared peccaries, agoutis, cavies, and armadillos to preserve their ovarian and testicular tissues. Additionally, domestic species such as the domestic cat and donkeys have been proposed as models for wild species that are phylogenetically close. This review addresses the main technical aspects involved in obtaining BRB derived from gonadal tissues in some wild species of the Caatinga biome. It reports recent advances and perspectives to use these biological materials for wildlife conservation.

Influence of telomerase activity and initial distribution on human follicular aging: Moving from a discrete to a continuum model

A discrete model is proposed for the temporal evolution of a population of cells sorted according to their telomeric length. This model assumes that, during cell division, the distribution of the genetic material to daughter cells is asymmetric, i.e. chromosomes of one daughter cell have the same telomere length as the mother, while in the other daughter cell telomeres are shorter. Telomerase activity and cell death are also taken into account. The continuous model is derived from the discrete model by introducing the generational age as a continuous variable in [0,h], being h the Hayflick limit, i.e. the number of times that a cell can divide before reaching the senescent state. A partial differential equation with boundary conditions is obtained. The solution to this equation depends on the initial telomere length distribution. The initial and boundary value problem is solved exactly when the initial distribution is of exponential type. For other types of initial distributions, a numerical solution is proposed. The model is applied to the human follicular growth from preantral to preovulatory follicle as a case study and the aging rate is studied as a function of telomerase activity, the initial distribution and the Hayflick limit. Young, middle and old cell-aged initial normal distributions are considered. In all cases, when telomerase activity decreases, the population ages and the smaller the h value, the higher the aging rate becomes. However, the influence of these two parameters is different depending on the initial distribution. In conclusion, the worst-case scenario corresponds to an aged initial telomere distribution.

Tumor-Derived Oxidative Stress Triggers Ovarian Follicle Loss in Breast Cancer

Breast cancer is a common indication for ovarian cryopreservation. However, whether the grafting ovarian tissue meets functional requirements, as well as the need for additional interventions, remains unclear. The current study demonstrates abnormal serum hormones in breast cancer in humans and breast cancer cell line-derived tumor-bearing mice, and for the first time shows tumor-induced loss of primordial and growing follicles and the number of follicles being lost to either growth or atresia. A gene signature of tumor-bearing mice demonstrates the disturbed regulatory network of steroidogenesis, which links to mitochondria dysfunction in oocytes and granulosa cells via the phosphatidylinositol 3-kinase signaling pathway. Notably, increased reactive oxygen species are identified in serum and ovarian tissues in tumor-bearing mice. Furthermore, supplementation with vitamin C promotes follicular quiescence, repairing tumor-induced follicle loss via inactivation of the phosphatidylinositol 3-kinase-Akt-mammalian target of rapamycin pathway, indicating that antioxidants should be a potential fertility therapy to achieve more numbers of healthy follicles ready for ovarian cryopreservation.

Meiotic Development of Canine Oocytes from Poly-Ovular and Mono-Ovular Follicles after In Vitro Maturation

Poly-ovular follicles are defined as those with more than one oocyte present in single follicles. The occurrence frequency of this follicle type is higher in canines than that in other species. This study aimed to evaluate the in vitro meiotic maturation of dog oocytes from this follicle type in comparison to those from mono-ovular follicles of various sizes (small antral, medium antral, and large antral) considering different phases of the estrus cycle (anestrus, proestrus, estrus, and diestrus). Canine oocytes were obtained separately from the poly-ovular and mono-ovular antral follicles from the ovaries of adult females. In each experimental replicate, cumulus-oocyte complexes (COCs) from poly-ovular and mono-ovular follicles were incubated in supplemented TCM-199 at 38.5 °C and 5% CO₂ for 72 h. After culturing, the meiotic development of each oocyte was evaluated using epifluorescence microscopy. Meiotic stages were classified into germinal vesicle (GV), germinal vesicle breakdown (GVBD), first metaphase (MI), and second metaphase (MII). Data were evaluated using an analysis of variance. Oocytes from poly-ovular follicles at all phases exhibited a higher (p < 0.05) percentage of oocytes arrested at the GV stage than those from mono-ovular follicles, showing the highest rate of GV in small antral follicles during anestrus. In contrast, there were no differences in MII rates (p < 0.05) in oocytes from mono-ovular and poly-ovular follicles during the estrus and diestrus phases in all sizes evaluated, with the highest MII rate in estrus. These results suggest that oocytes from poly-ovular follicles can resume meiosis at a slower rate than those from mono-ovular follicles; however, the maturation in vitro of such oocytes is possible. Furthermore, the relationship between the maturation capacity of oocytes from both poly-ovular and mono-ovular follicles depends on the ovarian cycle and follicular development.

The Contribution of the Sheep and the Goat Model to the Study of Ovarian Ageing

Ovarian ageing stands as the major contributor towards fertility loss. As such, there is an urge for studies addressing the mechanisms that promote ovarian ageing and new strategies aiming to delay it. Recently, the presence of a unique population of multinucleated giant cells has been identified in the ovaries of reproductively aged mice. These cells have been considered hallmarks of ovarian ageing. However, up to date multinucleated giant cells have only been described in the ovaries of the mice. Therefore, the aim of the present work was to evaluate and characterize the presence of such hallmarks of ovarian ageing in the sheep and the goat. In this study, ovaries from juvenile (6 months) and mature animals (18-24 months) were used. The hematoxylin and eosin technique was performed to describe the ovarian morphology and evaluate the ovarian follicle reserve pool. Sudan black B staining and the detection of autofluorescence emission were used to identify and characterize the presence of multinucleated giant cells. Statistical analyses were performed with GraphPad Prism 9.0.0. A decrease in the follicle reserve pool and the presence of multinucleated giant cells, with lipofuscin accumulation and the emission of autofluorescence, were observed in the ovaries of the mature animals of both species. Our results support the interest in the use of the ovine and the caprine model, that share physiological and pathophysiological characteristics with humans, in future studies addressing ovarian ageing.

Oocyte Arrested at Metaphase II Stage were Derived from Human Pluripotent Stem Cells in vitro

Initiation of meiosis is the most difficult aspect of inducing competent oocytes differentiation from human stem cells in vitro. Human induced pluripotent stem cells (hiPSCs) and embryonic stem cells (hESCs) were cultured with follicle fluid, cytokines and small molecule to induced oocyte-like cells (OLCs) formation through a three-step induction procedure. Expression of surface markers and differentiation potential of germ cells were analyzed in vitro by flow cytometry, gene expression, immunocytochemistry, western blotting and RNA Sequencing. To induce the differentiation of hiPSCs into OLCs, cells were firstly cultured with a primordial germ cell medium for 10 days. The cells exhibited similar morphological features to primordial germ cells (PGCs), high expressing of germ cell markers and primordial follicle development associated genes. The induced PGCs were then cultured with the primordial follicle-like cell medium for 5 days to form the induced follicle-like structures (iFLs), which retained both primordial oocytes-like cells and granulosa-like cells. In the third step, the detached iFLs were harvested and transferred to the OLC-medium for additional 10 days. The cultured cells developed cumulus-oocyte-complexes (COCs) structures and OLCs with different sizes (50-150 μm diameter) and a zona pellucida. The in vitro matured OLCs had polar bodies and were arrested at metaphase II (MII) stage. Some OLCs were self-activated and spontaneously developed into multiple-cell structures similar to preimplantation embryos, indicating that OLCs were parthenogenetically activated though in vitro fertilization potential of OLCs are yet to be proved. in vitro maturation of OLCs derived from hiPSCs provides a new means to study human germ cell formation and oogenesis.

Reduced-Intensity Conditioning Mitigates Risk for Primary Ovarian Insufficiency but Does Not Decrease Risk for Infertility in Pediatric and Young Adult Survivors of Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation (HSCT) is a curative therapy for many pediatric malignant and nonmalignant conditions. Gonadal insufficiency or infertility is present in almost all HSCT survivors who received a myeloablative conditioning (MAC) regimen. Reduced-intensity conditioning (RIC) regimens are being increasingly used in medically fragile patients or in patients with nonmalignant diagnoses to limit the toxicities associated with HSCT; however, the short-term and long-term gonadal toxicity of RIC regimens in pediatric and young adult survivors remains unknown. In this study, we compared the prevalence of gonadal insufficiency and infertility among pubertal and postpubertal pediatric and young adult survivors of HSCT who received a RIC regimen versus those who received a MAC regimen. Twenty-three females (RIC, n = 8; MAC, n = 15) and 35 males (RIC, n = 19; MAC, n = 16) were included in this single-center, retrospective cross-sectional study. Eligible patients were those with available laboratory results who were ≥1 year post-HSCT, age <40 years, and pubertal or postpubertal as assessed by an endocrinologist. Follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, and anti-Müllerian hormone (AMH) levels were measured in females, and FSH, LH, total testosterone, and inhibin B (InhB) levels were measured in males. Twenty-one males (RIC, n = 11; MAC, n = 10) underwent semen analysis through a separate consent. Parametric and nonparametric analyses were undertaken to compare the RIC and MAC groups. Female patients who received RIC were less likely than those who received MAC to develop primary ovarian insufficiency, as demonstrated by elevated FSH (P = .02) and low estradiol (P = .01) or elevated LH (P = .09). Most females in the RIC (75%) and MAC (93%) groups had low AMH levels, indicating low or absent ovarian reserve, with no significant difference between the groups (P = .53). In males, there were no significant differences between the 2 groups in the prevalence of abnormal FSH, LH, testosterone, or InhB levels. Ten of 11 RIC males (91%) and 10 of 10 MAC males (100%) had azoospermia or oligospermia, at a median time to semen analysis from HSCT of 3.7 years (range, 1.3 to 12.2 years). RIC may pose less risk than MAC for primary ovarian insufficiency among female survivors of HSCT; however, both female and male recipients of either RIC or MAC regimens are at high risk for infertility. In the largest reported series of semen analyses of pediatric and young adult male recipients of RIC, azoospermia or oligospermia was found in nearly all (91%) RIC survivors. All patients undergoing HSCT should receive counseling about the high risk of gonadal toxicity, and efforts should be made to preserve fertility in patients undergoing either RIC or MAC.

Evolving roles of activins and inhibins in ovarian cancer pathophysiology

Activins and inhibins are unique members of the transforming growth factor-β (TGFβ) family of growth factors, with the ability to exert autocrine, endocrine, and paracrine effects in a wide range of complex physiologic and pathologic processes. Although first isolated within the pituitary, emerging evidence suggests broader influence beyond reproductive development and function. Known roles of activin and inhibin in angiogenesis and immunity along with correlations between gene expression and cancer prognosis suggest potential roles in tumorigenesis. Here, we present a review of the current understanding of the biological role of activins and inhibins as it relates to ovarian cancers, summarizing the underlying signaling mechanisms and physiologic influence, followed by detailing their roles in cancer progression, diagnosis, and treatment.

Knockdown of regulatory associated protein of TOR (raptor) in hypothalamus-stimulated folliculogenesis and induced ovarian cysts

CONTEXT

Mammalian target of rapamycin complex 1 (mTORC1) is an essential sensor that regulates fundamental biological processes like cell growth, proliferation and energy metabolism. The treatment of disease by sirolimus, a mTORC1 inhibitor, causes adverse effects, such as female fertility disorders.

AIMS

The objective of the study was to decipher the reproductive consequences of a downregulation of mTORC1 in the hypothalamus.

METHODS

The reduced expression of mTORC1 was induced after intracerebroventricular injection of lentivirus expressing a short hairpin RNA (shRNA) against regulatory associated protein of TOR (raptor) in adult female mice (ShRaptor mice).

KEY RESULTS

The ShRaptor mice were fertile and exhibited a 15% increase in the litter size compared with control mice. The histological analysis showed an increase in antral, preovulatory follicles and ovarian cysts. In the hypothalamus, the GnRH mRNA and FSH levels in ShRaptor mice were significantly elevated.

CONCLUSIONS

These results support the hypothesis that mTORC1 in the central nervous system participates in the regulation of female fertility and ovarian function by influencing the GnRH neuronal activity.

IMPLICATIONS

These results suggest that a lower mTORC1 activity directly the central nervous system leads to a deregulation in the oestrous cycle and an induction of ovarian cyst development.

Mitochondrial Transfer into Human Oocytes Improved Embryo Quality and Clinical Outcomes in Recurrent Pregnancy Failure Cases

One of the most critical issues to be solved in reproductive medicine is the treatment of patients with multiple failures of assisted reproductive treatment caused by low-quality embryos. This study investigated whether mitochondrial transfer to human oocytes improves embryo quality and provides subsequent acceptable clinical results and normality to children born due to the use of this technology. We transferred autologous mitochondria extracted from oogonia stem cells to mature oocytes with sperm at the time of intracytoplasmic sperm injection in 52 patients with recurrent failures (average 5.3 times). We assessed embryo quality using the following three methods: good-quality embryo rates, transferable embryo rates, and a novel embryo-scoring system (embryo quality score; EQS) in 33 patients who meet the preset inclusion criteria for analysis. We also evaluated the clinical outcomes of the in vitro fertilization and development of children born using this technology and compared the mtDNA sequences of the children and their mothers. The good-quality embryo rates, transferable embryo rates, and EQS significantly increased after mitochondrial transfer and resulted in 13 babies born in normal conditions. The mtDNA sequences were almost identical to the respective maternal sequences at the 83 major sites examined. Mitochondrial transfer into human oocytes is an effective clinical option to enhance embryo quality in recurrent in vitro fertilization-failure cases.

Development of a digital anti-Müllerian hormone immunoassay: ultrasensitive, accurate and practical strategy for reduced ovarian reserve monitoring and assessment

Anti-Müllerian hormone (AMH) is an ideal biomarker for the assessment of ovarian reserve. However, its application in determining ovarian reserve reduction is restricted due to the low sensitivity of existing AMH assays. Herein, a homebrew ultrasensitive digital AMH assay (UD-AMH) was established based on a single-molecule array (SiMoA, HD-X platform), and the analytical performance of UD-AMH was evaluated systematically. The limit of detection (LoD) and limit of quantitation (LoQ) of UD-AMH were 0.13 and 0.14 pg/mL, respectively, which is approximately 100-fold higher than that of the current reported general clinical AMH assay. A comparison study showed a high correlation, with r = 0.988 for the Beckman Access AMH assay and r = 0.945 for the Kangrun AMH assay. In addition, we found that the AMH concentrations of premature ovarian insufficiency (POI) patients were very low (2.59 (0.86, 31.79) pg/mL) and similar to those of perimenopausal women (2.37 (0.65, 35.88) pg/mL) but significantly higher than those of menopausal women (0.43 (0.28, 1.17) pg/mL). Furthermore, we observed that the AMH concentration of most hormone therapy (HT) treated POI patients decreased sharply, suggesting that the ovarian reserve of POI patients declines over time even under HT-treatment.

A refined culture system of oocytes from early antral follicles promotes oocyte maturation and embryo development in cattle

In brief

The proposed culture system improves the current state of in vitro culture of growing oocytes in the bovine species and allows access to the untapped gamete reserve, thus improving reproductive efficiency.

Abstract

The present study aimed to improve the in vitro culture of bovine oocytes collected from early antral follicles (EAFs) to support the progressive acquisition of meiotic and developmental competence. The rationale that drove the development of such a culture system was to maintain as much as possible the physiological conditions that support the oocyte growth and differentiation in vivo. To this extent, oocytes were cultured for 5 days, which parallels the transition from early to medium antral follicles (MAFs) in the bovine, and supports promoting a 3D-like structure were provided. Additionally, the main hormones (follicle-stimulating hormone, estradiol, progesterone, and testosterone) were added in concentrations similar to the ones previously observed in bovine EAFs. The meiotic arrest was imposed using cilostamide. The cultured cumulus-oocyte complexes (COCs) reached a mean diameter of 113.4 ± 0.75 µm and showed a progressive condensation of the chromatin enclosed in the germinal vesicle (GV), together with a gradual decrease in the global transcriptional activity, measured by 5-ethynyl uridine incorporation. The described morpho-functional changes were accompanied by an increased ability to mature and develop to the blastocyst stage in vitro, although not matching the rates obtained by MAF-retrieved oocytes. The described system improves the current state of in vitro culture of growing oocytes in the bovine species, and it can be used to increase the number of gametes usable for in vitro embryo production in animals of high genetic merit or with specific desirable traits.

Turner syndrome: fertility counselling in childhood and through the reproductive lifespan

PURPOSE OF REVIEW

The potential for fertility in Turner syndrome has improved in recent years. Understanding of associated risks and approaches is important for the care of girls and women with this condition. This review focuses on reproductive health, fertility options and appropriate counselling for women with Turner syndrome and their families.

RECENT FINDINGS

Women with Turner syndrome have rapidly declining ovarian function beginning in utero . Therefore, counselling regarding fertility concerns should begin at a young age and involve discussion of options, including ovarian tissue cryopreservation, oocyte preservation and use of nonautologous oocytes. Clinical guidance on fertility management and pregnancy risk assessment based on karyotype, associated comorbidities and fertility is still not fully data driven. Realistic expectations regarding reproductive options and associated outcomes as well as the need for multidisciplinary follow-up during pregnancy are crucial to the ethical and safe care of these patients.

SUMMARY

Fertility care in women with Turner syndrome is evolving as current management techniques improve and new approaches are validated. Early counselling and active management of fertility preservation is critical to ensure positive and well tolerated reproductive outcomes.

VSELs and OSCs together sustain oogenesis in adult ovaries and their dysfunction results in age-related senescence, PCOS, POI and cancer

Multiple studies using single-cell RNA sequencing (scRNAseq) have failed to detect stem cells in adult ovaries. We have maintained that two populations of ovarian stem cells including pluripotent, very small embryonic-like stem cells (VSELs) and tissue-committed 'progenitors' termed ovarian stem cells (OSCs) can easily be detected in Hematoxylin and Eosin-stained ovary surface epithelial (OSE) cells smears prepared from both mice and human ovaries. Most likely the stem cells never get subjected to scRNAseq since they pellet down only by centrifuging cells suspension at 1000 g while cells for scRNAseq were invariably prepared by centrifuging at 200-400 g. A recent article provided further explanation for the failure of scRNAseq to detect ovarian stem cells. Extensive reanalysis of data (generated by scRNAseq) using an advanced software successfully detected OSCs and meiotic markers supporting neo-oogenesis in adult human ovaries. But this article remained critical on the biological relevance of VSELs and their relationship with OSCs. By carefully studying the OSE cells smears (which hold VSELs, OSCs and germ cell nests GCNs), prepared by partial trypsin digestion of intact mice ovaries during different stages of estrus cycle, we have successfully delineated novel functions of VSELs/OSCs in vivo under physiological conditions. VSELs undergo asymmetrical divisions to self-renew and give rise to slightly bigger OSCs which in turn undergo symmetrical divisions and clonal expansion to form GCNs, regular neo-oogenesis and follicle assembly. GCNs have been earlier described in fetal ovaries and during OSE cells culture (from adult ovaries) in response to FSH treatment. Dysfunction of VSELs/OSCs (which express ERα, ERβ, FSHR) due to neonatal exposure to endocrine disruption results in ovarian insufficiency and polycystic ovaries. VSELs have also been implicated in ovarian cancer. Age-related ovarian senescence/menopause is also due to dysfunction and blocked differentiation of VSELs/OSCs. These novel findings in vivo along with abundant in vitro and lineage tracing studies data in published literature provides huge scope for further research, offers novel avenues to manage ovarian pathologies and calls for re-writing of textbooks.

Perfluoroalkyl Acids in Follicular Fluid and Embryo Quality during IVF: A Prospective IVF Cohort in China

BACKGROUND

Perfluoroalkyl acids (PFAA) have been measured in ovarian follicular fluid from women using in vitro fertilization (IVF), although associations between follicular fluid PFAA and IVF outcomes have been inconsistent.

OBJECTIVES

We investigated the association between follicular fluid PFAA and embryo quality in women undergoing IVF.

METHODS

We prospectively enrolled 729 women undergoing IVF treatment in Guangxi province, China, from July 2018 to December 2018. We measured 32 PFAA, including branched isomers, in follicular fluid using ultra-performance liquid chromatography coupled to tandem mass spectrometry. We applied restricted cubic splines, linear regression, and log-binominal regression models to investigate associations between follicular fluid PFAA and embryo quality, adjusting for confounding variables and investigated oocyte maturity as an intervening variable using causal mediation analysis. We further estimated the overall effect of the PFAA mixture on outcomes using Bayesian kernel machine regression (BKMR).

RESULTS

We detected 8 of 32 measured PFAA in >85% of follicular fluid samples. Higher PFAA concentrations were associated with fewer high-quality embryos from IVF. The high-quality embryo rates at the 50th percentile of linear perfluoro-1-octanesulfonate acid (n-PFOS), all branched PFOS isomers (Br-PFOS) and linear perfluoro-n-octanoic acid (n-PFOA) were -6.34% [95% confidence interval (CI): -9.45, -3.32%], -16.78% (95% CI: -21.98, -11.58%) and -8.66% (95% CI: -11.88, -5.43%) lower, respectively, than the high quality embryo rates at the reference 10th percentile of PFAA. Oocyte maturity mediated 11.76% (95% CI: 3.18, 31.80%) and 14.28% (95% CI: 2.95, 31.27%) of the n-PFOS and n-PFOA associations, respectively. The results of the BKMR models showed a negative association between the PFAA mixture and the probability of high-quality embryos, with branched PFOS isomers having posterior inclusion probabilities of 1 and accounting for the majority of the association.

DISCUSSION

Exposure to higher PFAA concentrations in follicular fluid was associated with poorer embryo quality during IVF. Branched PFOS isomers may have a stronger effect than linear PFOS isomers. More studies are needed to confirm these findings and to directly estimate the effects on pregnancy and live-birth outcomes. https://doi.org/10.1289/EHP10857.