Cumulus cell co-culture in media drops does not improve rescue in vitro maturation of vitrified-warmed immature oocytes.

Objective: To assess whether co-culture with vitrified-warmed cumulus cells (CCs) in media drops improves rescue in vitro maturation (IVM) of previously vitrified immature oocytes. Previous studies have shown improved rescue IVM of fresh immature oocytes when cocultured with CCs in a three-dimensional matrix. However, the scheduling and workload of embryologists would benefit from a simpler IVM approach, particularly in the setting of time-sensitive oncofertility oocyte cryopreservation (OC) cases.

The fate of bisphenol A, bisphenol S, and their respective glucuronide metabolites in ovarian cells.

Ovarian cells are critical for reproduction and steroidogenesis, which are functions that can be impacted by exposure to xenobiotics. As in other extra-hepatic tissues, biotransformation events may occur at the ovarian level. Such metabolic events deserve interest, notably as they may modulate the overall exposure and toxicity of xenobiotics.

Comparing the effects of bisphenol A, C, and F on bovine theca cells in vitro.

Endocrine disrupting chemicals (EDCs) target aspects of hormone activity. Tightly coordinated crosstalk between two somatic cells of the ovary, granulosa and theca cells, governs steroid hormone production and plays a critical role in reproduction. It is thus pertinent to understand the impact of EDCs on granulosa and theca cells.

Spindle abnormalities and chromosome misalignment in bovine oocytes after exposure to low doses of bisphenol A or bisphenol S.

Study Question: What are the effects of exposure to bisphenol A (BPA) or bisphenol S (BPS) during IVM on bovine oocyte maturation, spindle morphology and chromosome alignment?

Summary Answer: Exposure to BPA or BPS during IVM resulted in increased spindle abnormalities and chromosome misalignment, even at very low concentrations.

What Is Known Already: BPA is an endocrine disrupting chemical that alters oocyte maturation, spindle morphology and chromosome alignment in a range of species. The use of BPA substitutes, such as BPS, is increasing and these substitutes often display different potencies and mechanisms of action compared with BPA.

The impact of bisphenol S on bovine granulosa and theca cells.

Bisphenol S (BPS) is an endocrine-disrupting chemical with multiple potential mechanisms of action, including as an oestrogen receptor agonist. BPS is increasingly used in plastics and thermal receipts as a substitute for bisphenol A, which has been phased out due to concerns about human health implications. The ability of BPS to alter female reproductive function in mammals has not been widely studied, despite the importance of normal hormone signalling for female reproduction.

In Vitro Exposure of Human Luteinized Mural Granulosa Cells to Dibutyl Phthalate Affects Global Gene Expression.

Exposure to dibutyl phthalate (DBP) is ubiquitous among women of reproductive age. Previous studies in animal models and in human cells in vitro have shown that exposure to DBP disrupts ovarian function. Here, we examined the effect of DBP on global gene expression in mural granulosa cells (MGCs) in vitro.

Susceptibility of human cumulus cells to bisphenol a In vitro.

Bisphenol A (BPA) is detectable in follicular fluid. However, the effect of BPA exposure on human cumulus cells (CC) that surround the oocyte and are crucial for oocyte competence has been largely unexplored. We exposed primary cultures of CC to increasing concentrations of BPA [0,0.

Dibutyl phthalate impairs steroidogenesis and a subset of LH-dependent genes in cultured human mural granulosa cell in vitro.

Exposure to di-butyl phthalate (DBP) exerts negative effects on female fertility in animal models, but human studies remain limited. Here, the effects of DBP exposure on mural granulosa cell function were investigated in primary cultures from women undergoing in vitro fertilization. Cultured cells treated with various doses of DBP (0, 0.

Bisphenol-A exposure and gene expression in human luteinized membrana granulosa cells in vitro.

Study Question: Does bisphenol-A (BPA) affect gene expression in human membrana granulosa cells (MGC)?

Summary Answer: In vitro, short exposure to supra-physiological concentrations of BPA alters human MGC gene expression.

What Is Known Already: Exposure to BPA may interfere with reproductive endocrine signaling. In vitro studies, mostly in animal models, have shown an inverse correlation between exposure to BPA and follicular growth, meiosis, and steroid hormone production in granulosa cells.

Bisphenol-A and human oocyte maturation in vitro.

Study Question: Does exposure to bisphenol-A (BPA) affect the maturation of human oocytes in vitro?

Summary Answer: There was a dose-response association of BPA exposure with altered human oocyte maturation in vitro.

What Is Known Already: There is widespread exposure of the general population to BPA. BPA has been detected in the human follicular fluid.

The use of immature oocytes in the fertility preservation of cancer patients: current promises and challenges.

Improved oncological treatments permit increased survival rates, although cancer patients remain at risk of losing ovarian function. An attractive option for fertility preservation includes the use of immature oocytes, a strategy which can occur on a rapid timeline and without hormonal stimulation. As a result, cancer therapy can proceed promptly even in patients with hormone-sensitive tumors.

The antral follicle: a microenvironment for oocyte differentiation.

Mammalian reproduction hinges upon the timely ovulation of a fully differentiated oocyte. This event is the culmination of a complex and dynamic developmental relationship between the oocyte and the antral follicle housing it; the antral follicle constitutes a specialized microenvironment or niche, uniquely suited to the needs of the oocyte as it approaches ovulation. During this time, the oocyte must complete its final growth, capacitation, and nuclear and cytoplasmic maturation.

Over 40 years of mentoring, educating, and researching in the world of oocytes.

David Albertini has dedicated his life to illuminating our understanding of the most wondrous of cells--the oocyte. Beyond his powerful scientific contributions, he has mindfully and tirelessly mentored and educated scientists and clinicians in our field. In this essay which reports a dialogue, David Albertini shares some of the key experiences that have governed his career path.

Follicular fluid hydrogen peroxide and lipid hydroperoxide in bovine antral follicles of various size, atresia, and dominance status.

Purpose: To avoid inducing a state of oxidative stress (OS), assisted reproductive technologies (ART) must maintain a balance of reactive oxygen species (ROS) and antioxidants during the in vitro culture of oocytes. However, oocyte requirements and tolerance thresholds for ROS during in vivo development are still unclear. Previous studies have examined ROS levels in follicular fluid (FF) using pooled samples or according to follicle size.

The association between severe obesity and characteristics of failed fertilized oocytes.

Study Question: Is the cytoskeletal and chromosomal organization of failed fertilized oocytes from severely obese patients (BMI ≥ 35 kg/m²) altered compared with that in patients with normal BMI (BMI 18.5-24.9 kg/m²)?

Summary Answer: Compared with normal BMI patients, severe obesity was associated with a greater prevalence of spindle anomalies and non-aligned chromosomes in failed fertilized oocytes.

Media composition: antioxidants/chelators and cellular function.

Protection of embryos against oxidative insults during culture is necessary to maintain viability. Generation of excessive levels of reactive oxygen species (ROS) is triggered by various components of the in vitro environment, most of which embryos do not normally encounter in vivo. To compensate for these deficiencies in the culture environment, antioxidants and chelators are often used to control or suppress ROS levels as embryos develop.

Is it best to cryopreserve human cumulus-free immature oocytes before or after in vitro maturation?

Freezing unfertilized oocytes is an option for females without a partner, either to preserve their fertility prior to sterilizing cancer treatment or for social reasons. Our study considered whether it is best to freeze immature human oocytes at the germinal vesicle (GV) stage, prior to in vitro maturation (IVM) or at metaphase-II (M-II), after IVM. Sibling GV-stage oocytes from stimulated ICSI cycles were allocated to freezing either prior to (n=109) or after (n=107) IVM.

Unique patient issues: early interventions and management.

Patient cases that present with recurring fertilization failure or complete abnormality in either the oocytes or sperm before fertilization are uncommon, yet they are devastating. This review presents several such instances, including oocyte maturation blocks, empty follicle syndrome, oocyte activation failures, defects in sperm phospholipase C isoform ζ, sperm structural anomalies, spontaneous oocyte activation, and unexplained cases. Diagnostic efforts have not only provided insight into possible etiologies but also have helped manage such challenging cases.

Release of superoxide dismutase-1 by day 3 embryos of varying quality and implantation potential.

Purpose: To determine if the antioxidant superoxide dismutase-1 (SOD1 or Cu,Zn-SOD) is released by cultured human cleavage-stage embryos and to assess any link between SOD1 and implantation potential.

Methods: Women (n = 91; ≤40 years old) undergoing IVF treatment with transfer of one or two 8-cell embryos that resulted in 0 or 100% implantation were included. Following individual embryo culture, spent medium samples (n = 122) were collected and levels of SOD1 protein were measured by an enzyme-linked immunosorbent assay.

Maturation outcomes are improved following Cryoleaf vitrification of immature human oocytes when compared to choline-based slow-freezing.

Purpose: The cryopreservation of immature oocytes permits oocyte banking for patients at risk of losing their fertility. However, the optimum protocol for such fertility preservation remains uncertain.

Methods: The present study investigated the survival, maturation, cytoskeletal and chromosome organization of sibling immature oocytes leftover from controlled ovarian stimulation cycles, that were either slow-frozen (with choline-substitution) or vitrified.

Fluctuations in total antioxidant capacity, catalase activity and hydrogen peroxide levels of follicular fluid during bovine folliculogenesis.

Follicular fluid is an important environment for oocyte development, yet current knowledge regarding its in vivo oxidant and antioxidant levels remains limited. Examining follicular fluid oxidants and antioxidants will improve understanding of their changes in vivo and contribute to optimisation of in vitro maturation conditions. The aim of the present study was to consider selected markers, namely catalase (CAT) enzyme activity, total antioxidant capacity (TAC) and hydrogen peroxide (H(2)O(2)) in follicular fluid samples (n = 503) originating from bovine antral follicles.

The nuclear mitotic apparatus (NuMA) protein: localization and dynamics in human oocytes, fertilization and early embryos.

The oocyte's meiotic spindle is a dynamic structure that relies on microtubule organization and regulation by centrosomes. Disorganization of centrosomal proteins, including the nuclear mitotic apparatus (NuMA) protein and the molecular motor complex dynein/dynactin, can lead to chromosomal instability and developmental abnormalities. The present study reports the distribution and function of these proteins in human oocytes, zygotes and early embryos.

Aberrant spindle structures responsible for recurrent human metaphase I oocyte arrest with attempts to induce meiosis artificially.

BACKGROUND In some couples, not all retrieved oocytes mature, even after prolonged in vitro culture. The underlying mechanisms are not known, although ionophore treatment may alleviate metaphase I (MI) arrest in some mouse strains. We attempted to induce first polar body (PB) extrusion and fertilization using assisted oocyte activation (AOA) after ICSI in maturation-resistant human MI oocytes.

Cellular and genetic analysis of oocytes and embryos in a human case of spontaneous oocyte activation.

Unusual and consistent defects in infertility patients merit attention as these may indicate an underlying genetic abnormality, in turn necessitating tailored management strategies. We describe a case of repeated early pregnancy loss from in vivo conceptions, followed by cancelled embryo transfers after one IVF and one ICSI/PGD cycle. Following the unexpected presence of cleaved embryos at the fertilization check in the first IVF attempt, oocytes and embryos were subsequently analyzed in an ICSI/PGD case.