Search Results (568)

Background/Objectives: Women undergoing fertility preservation by oocyte vitrification before oncological treatments often have a poorer ovarian response to stimulation than healthy women. This indicates that cancer itself can adversely affect ovarian function. However, this impact remains unclear, and its underlying mechanisms are poorly understood. We investigated in this study whether breast cancer, the most common form of cancer in women of reproductive age, alters ovarian function by itself. Methods: For this purpose, we compared the ovarian response to hormonal stimulation in women with breast cancer undergoing oocyte cryopreservation with that in oocyte donors, adjusting for age and BMI. We analysed our data according to the molecular subtype of breast cancer, tumour grade, lymph node invasion, and BRCA1 mutation status. Secondly, we evaluated whether breast cancer alters cholesterol homeostasis in cumulus cells, given its essential role in oocyte quality. The expression of genes involved in cholesterol biosynthesis was analysed in cumulus cells using RT-qPCR, while the concentrations of cholesterol and its intermediates were quantified in follicular fluid using GC-FID and GC-MS/SIM. Results: Compared with oocyte donors, breast cancer patients exhibited a significant decrease in collected oocytes after stimulation. At the molecular level, our data revealed a significant deregulation of cholesterol biosynthesis gene expression in cumulus cells of women with breast cancer. The quantification of cholesterol and its intermediates in follicular fluid revealed altered concentrations in women with breast cancer, suggesting a disrupted follicular microenvironment. Conclusions: These findings suggest that breast cancer impairs ovarian function, at least in part, by disrupting cholesterol homeostasis, which can lead to reduced oocyte competence. Full article

Systemic lupus erythematosus is an autoimmune disease that mainly affects women of reproductive age. Its pathological manifestations directly and indirectly negatively affect the ovarian reserve, the quality of oocytes, and the precise mechanisms of meiosis. This review presents the molecular mechanisms by which lupus damages ovarian tissue and meiosis in oocytes. The role of chronic inflammation, impaired hormonal levels, and the presence of specific autoantibodies are considered. The available data on how oocyte structures (meiotic spindle, actin cytoskeleton, membrane organelles and chromatin) are damaged by lupus symptoms are summarized. Full article

Background/Objectives: Aging is increasingly recognized as a key determinant of changes in human tissue and cellular function. Women’s age, in particular, has been associated with reduced oocyte quality and negatively correlated with the expression of genes involved in endometrial decidualization and cellular function. The ability of endometrial cells to interact and allow the invasion of the growing embryo is defined as endometrial receptivity. Investigating age-related differences in human endometrial receptivity may expand our understanding of factors contributing to infertility. Methods: Stromal cells were isolated and cultured from endometrial pipelle biopsies (n = 28) obtained from female donors at the proliferative phase of the menstrual cycle. Protein and mRNA expression of the receptivity modulators OPN, CD44, and HOXA10 were analyzed by Western blot and real-time PCR, respectively. Results: Data presented a linear decrease in mRNA expression of OPN and HOXA10 (p = 0.0066, R² = 0. and p = 0.0036, R² = 0.529, respectively) with women’s increasing age, and a similar trend was evident at the protein level (OPN, p < 0,05; HOXA10, p < 0,01). Further analysis of the data included separating the samples into three age groups: 25–35 years, 36–40 years, and 41–46 years. ANOVA revealed a significant decrease in OPN and HOXA10 mRNA expression (p = 0.03158 and p = 0.02578, respectively). CD44 expression did not differ with age. Conclusions: OPN and HOXA10 are negatively correlated with increasing maternal age. These findings suggest that age-related alterations in key endometrial receptivity modulators may contribute to impaired implantation and could represent potential targets for diagnostic or therapeutic strategies in human implantation failure. Full article

Age-related decline in oocyte quality is closely associated with mitochondrial dysfunction and oxidative imbalance, which disrupt redox-sensitive meiotic signaling and compromise embryo developmental competence. Rescue in vitro maturation (r-IVM) enables the utilization of immature oocytes retrieved during conventional in vitro fertilization (IVF) cycles. However, the developmental potential of r-IVM oocytes remains limited, particularly in women of advanced maternal age. This study evaluated whether transient caffeine supplementation during r-IVM improves the developmental competence of immature human oocytes in clinical assisted reproduction technology cycles. Immature oocytes obtained during conventional IVF were cultured with or without short-term caffeine exposure during r-IVM prior to standard culture conditions. After maturation, metaphase II oocytes underwent intracytoplasmic sperm injection, and embryonic development was assessed by fertilization rate, day 3 good-quality embryo formation, and blastocyst development. Although caffeine supplementation did not significantly affect nuclear maturation rates, it significantly increased fertilization efficiency and the proportion of good-quality embryos compared with controls. These effects were most pronounced in women aged ≥ 37 years. Time-lapse morphokinetic analysis further revealed more synchronized developmental kinetics in embryos derived from caffeine-treated oocytes, resembling those derived from in vivo-matured oocytes. Collectively, these findings suggest that transient caffeine exposure during r-IVM enhances post-fertilization developmental competence. The underlying mechanisms remain to be elucidated, and future studies are required to determine whether redox-sensitive meiotic pathways and mitochondrial function are involved. Full article

Novel brominated flame retardants (NBFRs), including 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), are emerging endocrine-disrupting chemicals, though their direct effects on female gamete maturation remain insufficiently characterized. In this study, we used a refined zebrafish oocyte in vitro maturation (IVM) model integrating germinal vesicle breakdown (GVBD) assessment with real-time, image-based oocyte diameter quantification. The workflow incorporated donor-condition optimization and diameter-based quality control during sorting. Oocytes from donors 4 to 5 months post-fertilization (mpf) showed more consistent diameter dynamics at the dish level than those from donors 3 to 4 mpf. Mixed-sex co-housing was associated with higher GVBD and larger Δdiameter than separated housing, although this comparison should be considered preliminary. Under DHP induction, BTBPE (1–1000 nM) consistently suppressed GVBD and attenuated maturation-associated diameter increases, with a non-monotonic-like response pattern. These findings indicate that BTBPE impairs oocyte maturation competence in vitro and supports real-time morphometric tracking as a practical QC component for zebrafish IVM workflows. Full article

Antioxidant supplementation during in vitro maturation (IVM) has been proposed as a strategy to influence transcriptional responses in oocytes and cumulus–oocyte complexes. In this study, we investigated whether vitamin C, rosmarinic acid, or quercetin influence the expression of key fertilisation-associated genes (CD9, ITGA6, MFGE8, ZP2, and ZP3) in porcine cumulus–oocyte complexes (COCs). COCs were classified into three intrinsic quality groups (I–III) and matured in the presence or absence of antioxidants. Gene expression was quantified by RT-qPCR and analysed using a two-way ANOVA model to assess the effects of COC quality and treatment. ZP2 and ZP3 transcript levels were consistently lower in class II and III COCs than in class I controls (p < 0.001). Antioxidant supplementation was associated with treatment- and quality-dependent differences in gene expression. Quercetin was associated with the most pronounced upregulation, with Q I increasing ZP2 expression to 2.95-fold and ZP3 to 2.43-fold relative to class I controls (p < 0.001). Vitamin C was also associated with increased transcript abundance across several treatment groups, including class II and class III COCs, whereas rosmarinic acid exhibited more moderate and gene-specific effects. In contrast, MFGE8 expression, which was elevated in lower-quality COCs, was reduced in antioxidant-treated class II and III complexes. These findings provide transcript-level evidence that antioxidant exposure during IVM is associated with treatment- and quality-dependent changes in fertilisation-related gene expression in porcine COCs. Full article

Conventional hormonal and clinical models inadequately clarify the complex and diverse aspects of female infertility, resulting in poor reproductive outcomes and reduced egg viability. A growing body of research indicates that female reproductive failure is mostly due to disruptions in cellular homeostasis, especially concerning organelle quality control. Oxidative stress has emerged as a crucial mediator connecting metabolic, inflammatory, and ageing-related processes to ovarian failure, however its downstream impacts on intracellular organelle turnover remain insufficiently clarified. Our narrative review encapsulates the existing data for a unified pathogenic concept focused on the redox-regulated mitochondria–lysosome axis. We examine the interaction of oxidative stress, mitochondrial malfunction, compromised mitophagy, and lysosomal deficiency in granulosa cells and oocytes. Prolonged oxidative stress may disrupt this equilibrium, leading to defective mitochondria accumulation and impaired mitophagy. This self-perpetuating cycle may ultimately jeopardises reproductive viability and oocyte integrity. The integrated axis offers a shared molecular foundation for various infertility-related diseases, such as inadequate ovarian response, obesity-associated infertility, polycystic ovary syndrome, and ovarian ageing. Ultimately, we analyse new findings suggesting that specific antioxidant chemicals modify mitophagy and lysosomal function while also neutralising reactive oxygen species, highlighting their potential use in precision fertility treatments. Our research redefines female infertility as a condition of redox-dependent organelle quality control, thereby introducing novel avenues for identifying biomarkers, categorising patients, and targeting treatments in assisted reproduction. Full article

Ovarian function relies on a network of well-coordinated molecular mechanisms that regulate follicular development, oocyte maturation, ovulation, and corpus luteum function. When these processes are disrupted, infertility can result. Extracellular matrix (ECM) remodeling represents a central regulatory component in these processes and is essential for follicle rupture and oocyte release. This mechanism involves metalloproteinases (MMPs), mainly MMP-2 and MMP-9, which degrade the ECM and allow the necessary structural changes. Other ECM-modulating proteases, such as ADAM and ADAMTS families, also contribute to this process. Their activity is tightly regulated by tissue inhibitors of metalloproteinases (TIMPs), ensuring that tissue remodeling occurs in a controlled manner. Disruption of the balance between MMPs and TIMPs increases the risk of infertility-related conditions such as polycystic ovary syndrome (PCOS), endometriosis, luteinizing hormone (LH) deficiency syndrome, and ovarian aging. In addition to the ECM, other factors, including intracellular signaling pathways, oxidative stress (OS), and mitochondrial function, contribute to ovarian physiology and directly affect oocyte quality and viability. This narrative review focuses on the molecular mechanisms governing ovarian function, with particular emphasis on the remodeling of the ECM by MMPs during ovulation, and examines how their disorders contribute to infertility. A deeper understanding of these mechanisms may lead to the identification of new therapeutic targets and the improvement of assisted reproduction outcomes. Full article

Due to its high efficiency and safety, oocyte vitrification finds broad application in many fields of life sciences, such as clinical assisted reproduction and conservation of animal genetic resources. However, vitrification may cause cellular damage and reduce the quality of oocytes and their cumulus cells (CCs), which could be closely related to disorders in lipid metabolism. At present, the impact of vitrification upon the lipid profile of oocytes and CCs has not been systematically elucidated. In this study, we used porcine germinal vesicle cumulus–oocyte complexes (COCs) as a model to analyze their lipid characteristics after vitrification and in vitro maturation (IVM), utilizing untargeted lipid metabolomics. Our results showed that an overall count of 37 down-regulated and 8 up-regulated differential lipids was identified in the vitrified oocytes. Pathway analysis confirmed the enrichment in glycerophospholipid metabolism and fat digestion and absorption, etc. Combined with transcriptomic analysis, three enriched pathways were revealed, including the AMPK signaling pathway, metabolic pathways, and fatty acid elongation. On the other hand, a total of four down-regulated and eight up-regulated differential lipids were detected in the vitrified CCs. Pathway enrichment implicated autophagy, glycerophospholipid metabolism, etc. A joint analysis of metabolomic and transcriptomic data revealed four enrichment pathways, including cholesterol metabolism, fat digestion and absorption, regulation of lipolysis in adipocytes, and metabolic pathways. Notably, the supplementation of lysophosphatidylcholine during IVM attenuated oxidative stress, enhanced mitochondrial activity, and enhanced the viability and embryonic development of cryopreserved porcine oocytes. The results indicate that vitrification alters lipids in oocytes and CCs, and the supplementation of lipids plays a role in improving the quality of vitrified oocytes. Full article

Non-invasive assessment of oocyte quality remains a challenge in assisted reproductive technology (ART). Through their bidirectional communication with the gamete, cumulus cells (CCs) act as a functional mirror of oocyte competence; however, the specific angiogenic signature within this microenvironment is still poorly understood. In the present study, we performed RNA-seq on CCs from healthy oocyte donors and infertile patients, utilizing a multi-pipeline bioinformatic approach (STAR-Cufflinks, TopHat-HTSeq, and HISAT2-StringTie) to establish a high-confidence, exploratory transcriptomic profile. A set of 234 differentially expressed genes (DEGs) consistently identified across pipelines was obtained, with functional enrichment highlighting blood vessel morphogenesis and angiogenesis as primary drivers of transcriptomic divergence between groups. RT-qPCR validation in individual samples confirmed statistically significant differences for ANKRD22 (upregulated) and E2F7 (downregulated) in infertile patients, while other angiogenesis-related genes, including ANGPT1, ANGPT2 and THBS1, showed consistent but non-significant expression trends, suggesting alterations in angiogenesis-related processes within the follicular microenvironment. These findings support the presence of coordinated angiogenesis-related alterations in cumulus cells and provide a basis for future studies exploring their potential relevance in oocyte competence and ART outcomes. Full article

Oocyte competency is a crucial determinant of fertilisation success and the initial development of embryos in assisted reproductive technologies. The metabolic and biochemical environment of the ovarian follicle is crucial for determining oocyte developmental potential, alongside genetic integrity. The follicular microenvironment includes a complex network of signalling chemicals that regulate mitochondrial activity, steroidogenesis, oxidative balance, and cellular energy metabolism. Recently, metabolic hormones originating from adipose tissue and skeletal muscle, namely, adipokines and myokines, have received considerable focus as crucial regulators of ovarian physiology. Adiponectin, irisin, and the recently identified hormone asprosin have emerged as crucial metabolic regulators influencing granulosa cell activity, mitochondrial bioenergetics, insulin signalling pathways, and redox homeostasis inside the follicular niche. Adiponectin mostly provides metabolic protection by activating AMP-activated protein kinase (AMPK) and improving insulin sensitivity, which in turn enhances mitochondrial efficiency and steroidogenic function in granulosa cells. Irisin, derived from the breakdown of fibronectin type III domain-containing protein 5 (FNDC5), aids the developing oocyte by facilitating mitochondrial biogenesis, augmenting oxidative phosphorylation, and altering cellular defence mechanisms against oxidative stress. Conversely, asprosin has been associated with glucogenic signalling, metabolic stress, and probable mitochondrial malfunction, suggesting a possible relationship between systemic metabolic problems and negative reproductive consequences. Clinical and experimental research indicate that the levels of these metabolic regulators in follicular fluid may correlate with ovarian response, oocyte quality, fertilisation rates, and embryo development during in vitro fertilisation cycles. This review consolidates current molecular, cellular, and clinical information, clarifying the pathways by which adipokines and myokines influence follicular metabolism and impact oocyte competency. Understanding the metabolic connections between systemic endocrine signals and the follicular milieu may provide novel indicators for reproductive prognosis and provide new treatment targets to improve assisted reproduction outcomes. Full article

Deoxynivalenol (DON) is a common mycotoxin linked to ovarian oxidative stress, toxicity, and reduced reproductive performance. Fermented Chinese chive is known for its antioxidant properties and potential reproductive benefits, but their individual and combined effects on ovarian function remain unclear in post-pubertal mice. In this study, a 21-day oral gavage model in female Kunming mice was used to evaluate the effects of DON (2 mg/kg/day), fermented Chinese chive extract (LEEK; 0.2 mL/day), and their combined exposure (LKDON) on ovarian physiology, oocyte quality, and ovarian transcriptomic responses. The results showed that DON exposure significantly reduced the zygote cleavage rate, increased intracellular reactive oxygen species levels, and disrupted oocyte mitochondrial membrane potential. While histological examination revealed disturbed follicular architecture. Transcriptomic hub gene analysis showed that DON exposure down-regulate the key associated with innate immune responses and motile cilia/axonemal structure, including Rsph4a, Drc1, Zmynd10, Hydin, and Tmem212. In contrast, LEEK alone was associated with immunomodulatory upregulated genes, including Il5, Cd27, and Crp. Interestingly, LKDON and DON comparison revealed upregulation of a motile cilia/axoneme gene network (Dnah5, Dnah11, Tekt1, Zmynd10, Cfap44, and Spag6l), rather than a global reversal of DON-induced changes. Overall, finding suggest that DON disrupts ovarian immune and structural pathways, while fermented Chinese chive provides partial protection by modulating specific biological processes. Further studies are needed to confirm the underlying mechanisms. Full article

Background/Objectives: Hyaluronic acid (HA) has been proposed as a physiological alternative to polyvinylpyrrolidone (PVP) for sperm immobilization during intracytoplasmic sperm injection (ICSI). This prospective sibling-oocyte study aimed to compare embryological outcomes and morphokinetic parameters between HA and PVP. Methods: A total of 811 sibling-oocytes from 51 ICSI cycles were allocated to the HA group (SpermCatch; n = 377) or the PVP group (10% PVP Solution; n = 434). Fertilization outcomes, cleavage, blastocyst formation, and good-quality embryo development were assessed. Embryo morphokinetic parameters (t2–tB) and an AI-derived embryo score were analyzed in a subset of blastocysts with available time-lapse data. Results: The fertilization rates were comparable between the HA and PVP groups (80.9% vs. 85.3%, p = 0.25), as were the cleavage rates (99.0% vs. 97.0%, p = 0.27). However, the HA group had significantly lower rates of good-quality cleavage-stage embryos (33.4% vs. 47.9%, p < 0.01), blastocyst formation (52.3% vs. 69.9%, p < 0.01), and good-quality blastocysts (49.4% vs. 64.1%, p < 0.01). Morphokinetic timings did not differ significantly, whereas embryos in the HA group showed lower AI scores than those in the PVP group (p = 0.04). Conclusions: In this prospective sibling-oocyte cohort, HA-based sperm immobilization did not improve embryological outcomes compared with conventional PVP-assisted ICSI. Differences observed at the blastocyst stage should be interpreted cautiously and require confirmation in larger, randomized studies with clinical follow-up. Full article

Background/Objectives: In the last decade, non-invasive methods for aneuploidy detection have been explored. The most successful approach involves analyzing the cell-free DNA (cfDNA) released by the embryo into the culture medium. The main objective of this study is to examine the technical feasibility of this new approach called non-invasive PGT-A or niPGT-A. In addition, as an exploratory objective, the impact of the niPGT-A results on clinic outcomes will be assessed. Methods: This was a multicenter, international study that included 716 patients and 2539 blastocysts (ClinicalTrials.gov: NCT03520933). Each embryo was cultured following a specific protocol for niPGT-A. Individual spent blastocyst medium (SBM) and trophectoderm (TE) biopsy were obtained, analyzed, and compared to assess concordance. In a subset of embryos, the comparison also included an inner cell mass (ICM) biopsy. Clinical outcomes from the embryo transfers performed (all based on the TE result) were registered, and results were analyzed blindly regarding the impact of aneuploidies in the culture medium. Results: The concordance rate between SBM and TE was 79.1% (range: 74.1–82.1; cycles with autologous oocytes). This value increased to 87.0% when comparing SBM and ICM. Applying an adapted embryo culture protocol to collect the SBM for niPGT-A did not affect blastocyst quality. Analysis of the embryo transfers performed (n = 265) revealed a trend towards lower miscarriage rate in blastocysts where both TE and SBM were concordant and euploid (13.0%), compared to blastocysts with a euploid TE and an aneuploid SBM (22.2%). Conclusions: The results obtained show a high concordance between the SBM and TE biopsies. Although additional refinement of the technique would further increase niPGT-A’s performance, the results obtained support the potential use of this non-invasive approach for aneuploidy detection. The high concordance of the cfDNA present in the SBM with the corresponding ICM biopsy and the miscarriage rate observed in cases with an aneuploid SBM, despite the euploid TE results, also support niPGT-A’s capacity to assess embryo aneuploidies and its potential as a prioritization system for selecting blastocysts to transfer. This approach could hold special interest in patients with no PGT-A indications, couples that prefer not to biopsy their embryos or those who do not have access to invasive PGT-A. Full article

Ovarian reserve and reproductive life are closely linked concepts in female reproductive biology. The ovarian reserve consists of primordial follicles and refers to the number and quality of oocytes (eggs) remaining in the ovaries at any given time. Follicular dynamics shape a woman’s reproductive lifespan, ultimately leading to menopause. Elucidating the underlying genetic and molecular pathways of follicle maturation and depletion is thus crucial for understanding menopausal onset and progression, both in normal and pathophysiological contexts, such as primary ovarian insufficiency, defined as menopause before the age of 40. A key factor in ovarian differentiation and fertility maintenance is FOXL2, a forkhead family transcription factor that plays a crucial role in follicle formation and development, ovarian maintenance, and sex determination. By employing a ChIP-Seq approach in mice, we identified a previously unreported binding of FOXL2 to a Tsc1 regulatory region. Our data, along with a thorough literature review, support the hypothesis that FOXL2-mediated activation of Tsc1 in granulosa cells can help maintain primordial follicles in a dormant state by suppressing mTORC1 signalling. Understanding the mechanisms behind ovarian reserve may lay the foundation for developing novel fertility preservation strategies, improving fertility treatment protocols and promoting in vitro activation of cryopreserved ovarian tissue to support folliculogenesis. Full article