The impact of Zearalenone on the meiotic progression and primordial follicle assembly during early oogenesis.

Zearalenone (ZEA) is a mycotoxin produced by fusarium graminearum. It can cause abnormal reproductive function by acting as an environmental estrogen. Research has traditionally focused on acute and chronic injury on mammalian reproductive capacity after ZEA treatment.

The role of germ cell loss during primordial follicle assembly: a review of current advances.

In most female mammals, early germline development begins with the appearance of primordial germ cells (PGCs), and develops to form mature oocytes following several vital processes. It remains well accepted that significant germ cell apoptosis and oocyte loss takes place around the time of birth. The transition of the ovarian environment from fetal to neonatal, coincides with the loss of germ cells and the timing of follicle formation.

Analysis of implantation and ongoing pregnancy rates following the transfer of mosaic diploid-aneuploid blastocysts.

Preimplantation genetic testing for aneuploidy (PGT-A) is widely used in IVF and aims to improve outcomes by avoiding aneuploid embryo transfers. Chromosomal mosaicism is extremely common in early development and could affect the efficacy of PGT-A by causing incorrect embryo classification. Recent innovations have allowed accurate mosaicism detection in trophectoderm samples taken from blastocysts.

Detection of mosaicism at blastocyst stage with the use of high-resolution next-generation sequencing.

A significant proportion of human preimplantation embryos produced during the course of in vitro fertilization (IVF) treatments contain two or more cytogenetically distinct cell lines. This phenomenon, known as chromosomal mosaicism, can involve the presence of cells with different types of aneuploidy in the absence of any normal cells or a mixture of euploid and abnormal cells. Although a high prevalence of mosaicism at the cleavage and blastocyst stages has been appreciated for two decades, the precise frequency of the phenomenon and its consequences for embryo viability have been difficult to quantify.

Cutaneous applied nano-ZnO reduce the ability of hair follicle stem cells to differentiate.

The ability of metal oxide nanoparticles to penetrate the skin has aroused a great deal of interest during the past decade due to concerns over the safety of topically applied sunscreens that contain physical UV-resistant metal particles, such as nano-Zinc oxide (nZnO). Previous studies demonstrate that metal oxide nanoparticles accumulate in skin furrows and hair follicles following topical application while little is known about the consequence of these nanoparticles on skin homeostasis. The current investigation tested the effects of nZnO (0.

The epigenetic modifications and the anterior to posterior characterization of meiotic entry during mouse oogenesis.

The meiotic initiation of mammalian oogonia is a critical step during the development of primordial germ cells (PGCs) to mature oocytes. In this study, a systematic investigation of epigenetic modifications and DAZL gene expression during oogonia meiotic entry were performed. We found that the expression of DAZL was epigenetically regulated by DNA methylation of CpG islands within its promoter region.

Starvation at birth impairs germ cell cyst breakdown and increases autophagy and apoptosis in mouse oocytes.

The female reproductive lifespan is largely determined by the size of primordial follicle pool, which is established following germ cell cyst breakdown around birth. Almost two-third of oocytes are lost during germ cell cysts breakdown, following autophagic and apoptosis mechanisms. To investigate a possible relationship between germ cell cyst breakdown and nutrition supply, we established a starvation model in mouse pups at birth and evaluated the dynamics of cyst breakdown during nutrient deprivation.

An altered endometrial CD8 tissue resident memory T cell population in recurrent miscarriage.

When trying to conceive 1% of couples have recurrent miscarriages, defined as three or more consecutive pregnancy losses. This is not accounted for by the known incidence of chromosomal aneuploidy in miscarriage, and it has been suggested that there is an immunological aetiology. The endometrial mucosa is populated by a variety of immune cells which in addition to providing host pathogen immunity must facilitate pregnancy.

CenpH regulates meiotic G2/M transition by modulating the APC/CCdh1-cyclin B1 pathway in oocytes.

Meiotic resumption (G2/M transition) and progression through meiosis I (MI) are two key stages for producing fertilization-competent eggs. Here, we report that CenpH, a component of the kinetochore inner plate, is responsible for G2/M transition in meiotic mouse oocytes. Depletion of CenpH by morpholino injection decreased cyclin B1 levels, resulting in attenuation of maturation-promoting factor (MPF) activation, and severely compromised meiotic resumption.

Embryos with morphokinetic abnormalities may develop into euploid blastocysts.

Irregular cleavage divisions are expected to produce chromosomally deviant embryos. We investigated whether embryos from irregular cleavages could develop into euploid blastocysts, and, if so, whether any evidence existed of a self-correction mechanism of the embryo. We also investigated the role of different dynamic aspects of morula compaction in this process.

Skin-derived stem cells as a source of primordial germ cell- and oocyte-like cells.

The skin is a unique organ that contains a variety of stem cells for the maintenance of skin homeostasis and the repair of skin tissues following injury and disease. Skin-derived stem cells (SDSCs) constitute a heterogeneous population of stem cells generated in vitro from dermis, which can be cultured as spherical aggregates of cells in suspension culture. Under certain in vitro or in vivo conditions, SDSCs show multipotency and can generate a variety of neural, mesodermal, and endodermal cell types such as neurons, glia, fibroblasts, adipocytes, muscle cells, chondroblasts, osteoblats, and islet β-cell-like cells.

Post-ovulatory aging of mouse oocytes in vivo and in vitro: Effects of caffeine on exocytosis and translocation of cortical granules.

The developmental potential of post-ovulatory oocytes decreases with aging in vivo and in vitro. In this study, we aimed to investigate the effects of a potent antioxidant caffeine on cortical granules (CGs) distribution in mouse oocytes aging in vivo and in vitro. We found that in vivo administration of 150 mg/kg caffeine caused ovulation of some morphologically abnormal oocytes showing premature exocytosis or congregation of CGs, but significantly decreased abnormal distribution of CGs in oocytes aging for 6 h, 12 h and 18 h in vivo compared to those without caffeine treatment.

Spc24 is required for meiotic kinetochore-microtubule attachment and production of euploid eggs.

Mammalian oocytes are particularly error prone in chromosome segregation during two successive meiotic divisions. The proper kinetochore-microtubule attachment is a prerequisite for faithful chromosome segregation during meiosis. Here, we report that Spc24 localizes at the kinetochores during mouse oocyte meiosis.

Repeated superovulation may affect mitochondrial functions of cumulus cells in mice.

Controlled ovarian stimulation by exogenous gonadotrophins is a key procedure during the in vitro fertilization cycle to obtain a sufficient number of oocytes in humans. Previous studies demonstrated that repeated superovulation had deleterious effects on the ovaries. However, whether repeated superovulation adversely affects the mitochondrial functions of cumulus cells remains unclear.

Why do euploid embryos miscarry? A case-control study comparing the rate of aneuploidy within presumed euploid embryos that resulted in miscarriage or live birth using next-generation sequencing.

Objective: To determine whether undetected aneuploidy contributes to pregnancy loss after transfer of euploid embryos that have undergone array comparative genomic hybridization (aCGH).

Design: Case-control study.

Setting: University-based fertility center.

Grade of the inner cell mass, but not trophectoderm, predicts live birth in fresh blastocyst single transfers.

Debate continues over which morphological parameter is most important in selecting blastocysts for transfer. We aimed to investigate which parameter more accurately predicts the occurrence of a live birth by designing a retrospective cohort study of 1084 fresh elective single blastocyst transfers. Primary outcome was live birth rate (LBR) and secondary outcomes were implantation, clinical pregnancy and early pregnancy loss rates.

Modulating mitochondrial quality in disease transmission: towards enabling mitochondrial DNA disease carriers to have healthy children.

One in 400 people has a maternally inherited mutation in mtDNA potentially causing incurable disease. In so-called heteroplasmic disease, mutant and normal mtDNA co-exist in the cells of carrier women. Disease severity depends on the proportion of inherited abnormal mtDNA molecules.

Di (2-ethylhexyl) phthalate impairs steroidogenesis in ovarian follicular cells of prepuberal mice.

Di (2-ethylhexyl) phthalate (DEHP) is a plasticizer which is widely used in the manufacture of plastics. As a common environmental contaminant and recognized endocrine disrupting chemical, DEHP is able to deregulate the functions of a variety of tissues, including the reproductive system both in males and females. In order to investigate the possible effects of DEHP on the first wave of folliculogenesis, occurring in the mouse ovary postnatally, mice were administered 20 or 40 μg/kg DEHP through intraperitoneal injection at days 5, 10 and 15 post partum (dpp).

Investigation of sperm telomere length as a potential marker of paternal genome integrity and semen quality.

Recent studies have reported shorter sperm telomere length (STL) in men with idiopathic infertility. The aim of this study was to measure STL in semen samples from men to evaluate whether STL variation is associated with chromosomal abnormality, DNA fragmentation, traditional semen parameters, IVF outcome, or all four factors. A significant correlation between telomere length and diploidy was observed (P = 0.

Does advancing male age influence the expression levels and localisation patterns of phospholipase C zeta (PLCζ) in human sperm?

Socio-economic factors have led to an increasing trend for couples to delay parenthood. However, advancing age exerts detrimental effects upon gametes which can have serious consequences upon embryo viability. While such effects are well documented for the oocyte, relatively little is known with regard to the sperm.

The why, the how and the when of PGS 2.0: current practices and expert opinions of fertility specialists, molecular biologists, and embryologists.

Study Question: We wanted to probe the opinions and current practices on preimplantation genetic screening (PGS), and more specifically on PGS in its newest form: PGS 2.0?

Study Finding: Consensus is lacking on which patient groups, if any at all, can benefit from PGS 2.0 and, a fortiori, whether all IVF patients should be offered PGS.

Polymorphisms in the MTHFR gene influence embryo viability and the incidence of aneuploidy.

MTHFR is an important enzyme in the metabolism of folic acid and is crucial for reproductive function. Variation in the sequence of MTHFR has been implicated in subfertility, but definitive data are lacking. In the present study, a detailed analysis of two common MTHFR polymorphisms (c.

SIRT1, 2, 3 protect mouse oocytes from postovulatory aging.

The quality of metaphase II oocytes will undergo a time-dependent deterioration following ovulation as the result of the oocyte aging process. In this study, we determined that the expression of sirtuin family members (SIRT1, 2, 3) was dramatically reduced in mouse oocytes aged in vivo or in vitro. Increased intracellular ROS was observed when SIRT1, 2, 3 activity was inhibited.