Patient- and cycle-specific factors affecting the outcome of frozen-thawed embryo transfers.

Purpose: This study attempted at identifying the main parameters influencing the outcome of frozen embryo transfers.

Methods: This is a single-center retrospective cohort study of 830 frozen-embryo-transfer cycles performed at a German university hospital from January 2012 to December 2016. Main outcome parameters were the clinical pregnancy and live birth rate.

and AKT/mTOR Signaling in Human Granulosa Cells: Functional Interaction and Impact on Ovarian Response.

We aimed to determine whether a functional link with impact on female ovarian reserve exists between expression and expression ratios of AKT/mTOR signaling genes in human granulosa cells in vivo, as suggested from prior in vitro data. Three hundred and nine women, who were classified as normal (NOR; = 225) and poor (POR; = 84) responders based on their ovarian reserve, were recruited during stimulation for assisted reproductive techniques. Expressions of and of key genes of the AKT/mTOR and AKT/FOXO1/3 signaling pathways were comparatively analyzed in their granulosa cells.

Non-invasive Embryo Assessment: Altered Individual Protein Profile in Spent Culture Media from Embryos Transferred at Day 5.

In order to improve ART outcome, non-invasive embryo assessment is gaining more and more attention. Therefore, the aim of this study is to determine the consecutive implantation potential via the secretome between blastocysts with or without implantation and to analyse possible interactions between these differentially expressed proteins. In this prospective study, 69 spent culture media from blastocysts transferred at day 5 were collected from patients undergoing IVF/ICSI treatment in a single IVF centre between April 2015 and November 2018 after informed consent and analysed individually.

In vitro maturation of immature oocytes from ovarian tissue prior to shipment to a cryobank.

Purpose: Female fertility preservation prior to gonadotoxic therapies can be achieved by the cryopreservation of ovarian cortical tissue. Immature oocytes may be recovered during the preparation, matured in vitro and lead to live births, thereby providing an additional option for fertility preservation. The purpose of this study was to test the feasibility of this approach in a setting with unilateral biopsy of a small piece of ovarian tissue and minimal tissue preparation prior to shipment to an external cryobank.

Relative Morphokinetics Assessed by Time-Lapse Imaging Are Altered in Embryos From Patients With Endometriosis.

Introduction: Time-lapse technology allows almost continuous noninvasive assessment of embryonic development. It was shown previously that relative kinetics defining cleavage synchronicity are better predictors of blastocyst quality than absolute time points. This study aims to compare relative kinetics in embryos from patients with and without endometriosis.

Pregnancy rates of day 4 and day 5 embryos after culture in an integrated time-lapse incubator.

Background: The aim of this study was to compare pregnancy rates in patients undergoing IVF/ICSI with embryo transfer after 4 and 5 days of culture in a closed incubation system with integrated time-lapse imaging.

Methods: Out of n = 2207 in vitro fertilization (IVF)/ intracytoplasmic sperm injection (ICSI) cycles performed between January 2011 and April 2016 at a tertiary referral university hospital, a total of n = 599 IVF/ICSI cycles with prolonged embryo culture in an integrated time-lapse system (EmbryoScope (Vitrolife)) until day 4 or 5 were retrospectively analyzed with regard to embryo morphology and pregnancy rates.

Results: A transfer on day 5 compared to a transfer on day 4 did not result in higher implantation and clinical pregnancy rates (IR 29.

Time-lapse imaging reveals differences in growth dynamics of embryos after in vitro maturation compared with conventional stimulation.

Objective: To study the impact of in vitro maturation (IVM) on embryonal development with the use of time-lapse imaging.

Design: Retrospective case-control study.

Setting: University hospital.

Venus trap in the mouse embryo reveals distinct molecular dynamics underlying specification of first embryonic lineages.

Mammalian development begins with the segregation of embryonic and extra-embryonic lineages in the blastocyst. Recent studies revealed cell-to-cell gene expression heterogeneity and dynamic cell rearrangements during mouse blastocyst formation. Thus, mechanistic understanding of lineage specification requires quantitative description of gene expression dynamics at a single-cell resolution in living embryos.

The Krüppel-associated box repressor domain can induce reversible heterochromatization of a mouse locus in vivo.

The study of chromatin and its regulators is key to understanding and manipulating transcription. We previously exploited the Krüppel-associated box (KRAB) transcriptional repressor domain, present in hundreds of vertebrate-specific zinc finger proteins, to assess the effect of its binding to gene bodies. These experiments revealed that the ectopic and doxycycline (dox)-controlled tet repressor KRAB fusion protein (tTRKRAB) can induce reversible and long-range silencing of cellular promoters.

Notch signaling regulates endocrine cell specification in the zebrafish anterior pituitary.

The vertebrate pituitary gland is a key endocrine control organ that contains six distinct hormone secreting cell types. In this study, we analyzed the role of direct cell-to-cell Delta-Notch signaling in zebrafish anterior pituitary cell type specification. We demonstrate that initial formation of the anterior pituitary placode is independent of Notch signaling.

Stochastic processes during mouse blastocyst patterning.

Mammalian preimplantation development serves to form a blastocyst, a structure that is able to implant into the mother's uterus to support further development of the embryo proper. In the developing conceptus, the first differentiation events separate the epithelial trophectoderm from the inner cell mass, which is comprised of the primitive endoderm and embryo-generating epiblast. Although the process of blastocyst formation may appear simple, its morphogenesis and the mechanism(s) of lineage specification are not yet fully understood.

Stochastic patterning in the mouse pre-implantation embryo.

Mouse pre-implantation development gives rise to the blastocyst, which is made up of at least three distinct cell types: the trophectoderm (TE) that surrounds a cavity, and an inner cell mass (ICM) comprising the primitive endoderm (PE) and epiblast (EPI). However, the underlying mechanisms involved in patterning the cleavage-stage embryo are still unresolved. By analyzing the distribution of the transcription factors Oct4 (Pou5f1), Cdx2 and Nanog at precisely defined stages in pre-implantation development, we were able to identify critical events leading to the divergence of TE, EPI and PE lineages.

Space asymmetry directs preferential sperm entry in the absence of polarity in the mouse oocyte.

Knowledge about the mechanism that establishes embryonic polarity is fundamental in understanding mammalian development. In re-addressing several controversial claims, we recently proposed a model in which mouse embryonic polarity is not specified until the blastocyst stage. Before fertilization, the fully differentiated oocyte has been characterized as "polarized," and we indeed observed that the sperm preferentially enters the polar body half.

pitx3 defines an equivalence domain for lens and anterior pituitary placode.

Hedgehog signaling is required for formation and patterning of the anterior pituitary gland. However, the role of Hedgehog in pituitary precursor cell specification and subsequent placode formation is not well understood. We analyzed pituitary precursor cell lineages and find that pitx3 and distal-less3b (dlx3b) expression domains define lens and pituitary precursor positions.