Journal articles on the topic 'Preimplantation embryo'
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1
Il'ková, Gabriela, Pavol Rehák, Jarmila Veselá, štefan Čikoš, Dušan Fabian, Soňa Czikková, and Juraj Koppel. "Serotonin localization and its functional significance during mouse preimplantation embryo development." Zygote 12, no. 3 (August 2004): 205–13. http://dx.doi.org/10.1017/s0967199404002862.
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Serotonin is a neurotransmitter functioning also as a hormone and growth factor. To further investigate the biological role of serotonin during embryo development, we analysed serotonin localization as well as the expression of specific serotonin 5-HT1D receptor mRNA in mouse oocytes and preimplantation embryos. The functional significance of serotonin during the preimplantation period was examined by studying the effects of serotonin on mouse embryo development. Embryo exposure to serotonin (1 μM) highly significantly reduced the mean cell number, whereas lower concentrations of serotonin (0.1 μM and 0.01 μM) had no significant effects on embryo cell numbers. In all serotonin-treated groups a significant increase in the number of embryos with apoptotic and secondary necrotic nuclei was observed. Expression of serotonin 5-HT1D receptor mRNA in mouse oocytes and preimplantation embryos was confirmed by in situ hybridization showing a clearly distinct punctate signal. Immunocytochemistry results revealed the localization of serotonin in oocytes and embryos to the blastocyst stage as diffuse punctate cytoplasmic labelling. It appears that endogenous and/or exogenous serotonin in preimplantation embryos could be involved in complex autocrine/paracrine regulations of embryo development and embryo-maternal interactions.
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Rager, Günter. "Präimplantationsdiagnostik und der Status des Embryos." Zeitschrift für medizinische Ethik 46, no. 2 (April 19, 2000): 81–89. http://dx.doi.org/10.30965/29498570-04602003.
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The debate about preimplantation genetic diagnosis (PGD) has put new life into the discussion about the various preimplantation stages of the human embryo. This article explains the embryological foundations for the description of preimplantation stages, provides an interpretation for the embryological findings (the embryo as a dynamic, self-organising system – twin development and individuality – the embryo as a person in becoming), and discusses problems with respect to individuality and personality of human embryos.
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Bueno, Aline, Yuri Karen Sinzato, Gustavo Tadeu Volpato, Franciane Quintanilha Gallego, Felipe Perecin, Tiago Rodrigues, and Débora Cristina Damasceno. "Severity of prepregnancy diabetes on the fetal malformations and viability associated with early embryos in rats†." Biology of Reproduction 103, no. 5 (September 1, 2020): 938–50. http://dx.doi.org/10.1093/biolre/ioaa151.
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Abstract Preexisting/pregestational diabetes enhances the risk of birth defects. Several factors have been involved during the implantation process, such as cytokines (granulocyte-macrophage–colony-stimulating factor [GM-CSF]). The objective was to evaluate the effects of two levels of diabetes on the redox status of preimplantation embryos during the implantation process to comprehend how both are involved in embryo and fetal viability against maternal diabetes. Female Sprague–Dawley rats received streptozotocin at birth (mild diabetes [MD]) or at adulthood (severe diabetes [SD]) to obtain two experimental diabetes intensities. After confirming the diabetic status, the nondiabetic and diabetic groups were mated around day 110 of life. At gestational day (GD) 21, fetuses were assessed for viability and malformations and ovaries for embryo loss before implantation. Other pregnant nondiabetic and diabetic rats were sacrificed at GD2–4 for maternal and preimplantation embryo oxidative stress markers, maternal serum insulin, uterine fluid GM-CSF, and preimplantation embryo morphological analysis. MD and SD caused abnormal redox levels, lower GM-CSF and insulin levels during the preimplantation period, and embryonic loss before implantation. SD caused lower fetal viability and higher fetal malformation percentages at GD21. The SD dam-derived preimplantation embryos presented lower glutathione levels and higher thiobarbituric acid reactive substances concentration at GD3 and an increased frequency of abnormal preimplantation embryos at GD4. In conclusion, preexisting diabetes leads to complications in the implantation process. Furthermore, maternal oxidative stress and other metabolic changes alter the redox state and morphological structure of preimplantation embryos, contributing to damaged growth and development in late pregnancy.
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Ding, Nai-Zheng, Cheng-Qiang He, and Zeng-Ming Yang. "Quantification of basigin mRNA in mouse oocytes and preimplantation embryos by competitive RT-PCR." Zygote 10, no. 3 (August 2002): 239–43. http://dx.doi.org/10.1017/s0967199402002319.
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Basigin is a member of the immunoglobulin superfamily and a key molecule related to mouse blastocyst implantation. Whether preimplantation mouse embryos express basigin mRNA is still unknown. The aim of this study was to use a quantitative competitive polymerase chain reaction to assess quantitatively the levels of basigin mRNA in mouse oocyte and preimplantation embryos. Basigin mRNA was detected in the oocyte and all the stages of preimplantation embryos. The levels of basigin mRNA were 0.0606 ± 0.0282 in the oocyte, 0.0102 ± 0.0036 in the zygote, 0.0007 ± 0.0003 in the 2-cell embryo, 0.0031 ± 0.0017 in the 4-cell embryo, 0.0084 ± 0.0024 in the 8-cell embryo, 0.0537 ± 0.0121 in the morula and 0.0392 ± 0.0161 attomoles in the blastocyst, respectively. The levels of basigin mRNA in the oocyte, morula and blastocyst were significantly higher than those in the zygote and embryos at the 2-cell, 4-cell and 8-cell stages. The high level of basigin expression in the blastocyst may play a role during embryo implantation.
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Lin, Tao, Jae Lee, Jung Kang, Hyeon Shin, Ju Lee, and Dong Jin. "Endoplasmic Reticulum (ER) Stress and Unfolded Protein Response (UPR) in Mammalian Oocyte Maturation and Preimplantation Embryo Development." International Journal of Molecular Sciences 20, no. 2 (January 18, 2019): 409. http://dx.doi.org/10.3390/ijms20020409.
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Mammalian oocytes and early embryos derived from in vitro production are highly susceptible to a variety of cellular stresses. During oocyte maturation and preimplantation embryo development, functional proteins must be folded properly in the endoplasmic reticulum (ER) to maintain oocyte and embryo development. However, some adverse factors negatively impact ER functions and protein synthesis, resulting in the activation of ER stress and unfolded protein response (UPR) signaling pathways. ER stress and UPR signaling have been identified in mammalian oocytes and embryos produced in vitro, suggesting that modulation of ER stress and UPR signaling play very important roles in oocyte maturation and the development of preimplantation embryos. In this review, we briefly describe the current state of knowledge regarding ER stress, UPR signaling pathways, and their roles and mechanisms in mammalian (excluding human) oocyte maturation and preimplantation embryo development.
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Duranthon, Veronique, Andrew J. Watson, and Patrick Lonergan. "Preimplantation embryo programming: transcription, epigenetics, and culture environment." REPRODUCTION 135, no. 2 (February 2008): 141–50. http://dx.doi.org/10.1530/rep-07-0324.
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Preimplantation development directs the formation of an implantation- or attachment-competent embryo so that metabolic interactions with the uterus can occur, pregnancy can be initiated, and fetal development can be sustained. The preimplantation embryo exhibits a form of autonomous development fueled by products provided by the oocyte and also from activation of the embryo's genome. Despite this autonomy, the preimplantation embryo is highly influenced by factors in the external environment and in extreme situations, such as those presented by embryo culture or nuclear transfer, the ability of the embryo to adapt to the changing environmental conditions or chromatin to become reprogrammed can exceed its own adaptive capacity, resulting in aberrant embryonic development. Nuclear transfer or embryo culture-induced influences not only affect implantation and establishment of pregnancy but also can extend to fetal and postnatal development and affect susceptibility to disease in later life. It is therefore critical to define the basic program controlling preimplantation development, and also to utilize nuclear transfer and embryo culture models so that we may design healthier environments for preimplantation embryos to thrive in and also minimize the potential for negative consequences during pregnancy and post-gestational life. In addition, it is necessary to couple gene expression analysis with the investigation of gene function so that effects on gene expression can be fully understood. The purpose of this short review is to highlight our knowledge of the mechanisms controlling preimplantation development and report how those mechanisms may be influenced by nuclear transfer and embryo culture.
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Kimber, S. J., S. F. Sneddon, D. J. Bloor, A. M. El-Bareg, J. A. Hawkhead, A. D. Metcalfe, F. D. Houghton, et al. "Expression of genes involved in early cell fate decisions in human embryos and their regulation by growth factors." REPRODUCTION 135, no. 5 (May 2008): 635–47. http://dx.doi.org/10.1530/rep-07-0359.
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Little is understood about the regulation of gene expression in human preimplantation embryos. We set out to examine the expression in human preimplantation embryos of a number of genes known to be critical for early development of the murine embryo. The expression profile of these genes was analysed throughout preimplantation development and in response to growth factor (GF) stimulation. Developmental expression of a number of genes was similar to that seen in murine embryos (OCT3B/4,CDX2,NANOG). However,GATA6is expressed throughout preimplantation development in the human. Embryos were cultured in IGF-I, leukaemia inhibitory factor (LIF) or heparin-binding EGF-like growth factor (HBEGF), all of which are known to stimulate the development of human embryos. Our data show that culture in HBEGF and LIF appears to facilitate human embryo expression of a number of genes:ERBB4(LIF) andLIFRandDSC2(HBEGF) while in the presence of HBEGF no blastocysts expressedEOMESand when cultured with LIF only two out of nine blastocysts expressedTBN. These data improve our knowledge of the similarities between human and murine embryos and the influence of GFs on human embryo gene expression. Results from this study will improve the understanding of cell fate decisions in early human embryos, which has important implications for both IVF treatment and the derivation of human embryonic stem cells.
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Warner, C. M., J. A. Newmark, M. Comiskey, S. R. De Fazio, D. M. O'Malley, M. Rajadhyaksha, D. J. Townsend, et al. "Genetics and imaging to assess oocyte and preimplantation embryo health." Reproduction, Fertility and Development 16, no. 7 (2004): 729. http://dx.doi.org/10.1071/rd04088.
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Two major criteria are currently used in human assisted reproductive technologies (ART) to evaluate oocyte and preimplantation embryo health: (1) rate of preimplantation embryonic development; and (2) overall morphology. A major gene that regulates the rate of preimplantation development is the preimplantation embryo development (Ped) gene, discovered in our laboratory. In mice, presence of the Ped gene product, Qa-2 protein, results in a fast rate of preimplantation embryonic development, compared with a slow rate of preimplantation embryonic development for embryos that are lacking Qa-2 protein. Moreover, mice that express Qa-2 protein have an overall reproductive advantage that extends beyond the preimplantation period, including higher survival to birth, higher birthweight, and higher survival to weaning. Data are presented that suggest that Qa-2 increases the rate of development of early embryos by acting as a cell-signalling molecule and that phosphatidylinositol-3′ kinase is involved in the cell-signalling pathway. The most likely human homologue of Qa-2 has recently been identified as human leukocyte antigen (HLA)-G. Data are presented which show that HLA-G, like Qa-2, is located in lipid rafts, implying that HLA-G also acts as a signalling molecule. In order to better evaluate the second criterion used in ART (i.e. overall morphology), a unique and innovative imaging microscope has been constructed, the Keck 3-D fusion microscope (Keck 3DFM). The Keck 3DFM combines five different microscopic modes into a single platform, allowing multi-modal imaging of the specimen. One of the modes, the quadrature tomographic microscope (QTM), creates digital images of non-stained transparent cells by measuring changes in the index of refraction. Quadrature tomographic microscope images of oocytes and preimplantation mouse embryos are presented for the first time. The digital information from the QTM images should allow the number of cells in a preimplantation embryo to be counted non-invasively. The Keck 3DFM is also being used to assess mitochondrial distribution in mouse oocytes and embryos by using the k-means clustering algorithm. Both the number of cells in preimplantation embryos and mitochondrial distribution are related to oocyte and embryo health. New imaging data obtained from the Keck 3DFM, combined with genetic and biochemical approaches, have the promise of being able to distinguish healthy from unhealthy oocytes and embryos in a non-invasive manner. The goal is to apply the information from our mouse model system to the clinic in order to identify one and only one healthy embryo for transfer back to the mother undergoing an ART procedure. This approach has the potential to increase the success rate of ART and to decrease the high, and undesirable, multiple birth rate presently associated with ART.
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Papaioannou, Virginia E., and Richard R. Behringer. "Phenotypic Analysis of Preimplantation Mouse Embryos in Culture." Cold Spring Harbor Protocols 2023, no. 12 (November 6, 2023): pdb.prot108090. http://dx.doi.org/10.1101/pdb.prot108090.
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Preimplantation embryo culture is a valuable approach to investigate a preimplantation lethal phenotype. Standard culture methods have been perfected such that the entire preimplantation period and the process of implantation can be followed in vitro. This protocol provides modifications for the analysis of clutches of embryos from heterozygous matings specifically for the purpose of distinguishing a preimplantation phenotype in homozygous mutants.
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Delhanty, JDA, and JC Harper. "Preimplantation genetic diagnosis." Reproductive Medicine Review 10, no. 1 (March 2002): 3–20. http://dx.doi.org/10.1017/s096227990200011x.
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The aim of preimplantation genetic diagnosis (PGD) is to give couples at risk of passing on a genetic disorder an alternative to standard prenatal diagnosis by enabling them to start a pregnancy that is known to be free of the familial disease. This can be achieved by generating embryos in vitro by standard in vitro fertilization (IVF) techniques and then removing one to two of the cells from the early embryo (embryo biopsy). Single cell polymerase chain reaction (PCR) or fluorescence in situ hybridization (FISH) can then be used to diagnose single gene defects or chromosomal abnormalities respectively. Those embryos diagnosed as free from disease can then be considered for transfer to the womb and so the pregnancy is started knowing that the fetus is unaffected. This avoids the need to consider pregnancy termination in the quest for a healthy child. Originally it was thought that the major reason for referral would be the risk of passing on a single abnormal gene but an increasing proportion of couples are requesting PGD because of recurrent miscarriage due to parental chromosomal abnormality.
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O'Neill, Chris. "Phosphatidylinositol 3-kinase signaling in mammalian preimplantation embryo development." REPRODUCTION 136, no. 2 (August 2008): 147–56. http://dx.doi.org/10.1530/rep-08-0105.
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The development of the preimplantation mammalian embryo is an autopoietic process; once initiated development proceeds without an absolute requirement for external information or growth cues. This developmental autonomy is partly explained by the generation of autocrine trophic ligands that are released and act back on the embryo via specific receptors. Several embryotrophic ligands cause receptor-dependent activation of 1-o-phosphatidylinositol 3-kinase. This enzyme phosphorylates phosphatidylinositol-4,5-bisphosphate to form phosphatidylinositol-3,4,5-trisphosphate. Genetic or pharmacological ablation of this enzyme activity disrupts normal development of preimplantation embryos. Phosphatidylinositol-3,4,5-trisphosphate is a membrane lipid that acts as a docking site for a wide range of proteins possessing the pleckstrin homology (PH) domain. Such proteins are important regulators of cell survival, proliferation, and differentiation. RAC-α serine/threonine protein kinase is an important PH domain protein and its activity is required for normal preimplantation embryo development and survival. The activity of a range of PH domain proteins is also implicated in the normal development of the embryo. This review critically examines the evidence for the activation of 1-o-phosphatidylinositol 3-kinase in the generation of pleiotypic trophic response to embryotrophins in the autopoietic development of the preimplantation embryo.
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Jin, X. L., and C. O’Neill. "cAMP-responsive element-binding protein expression and regulation in the mouse preimplantation embryo." Reproduction 134, no. 5 (November 2007): 667–75. http://dx.doi.org/10.1530/rep-07-0249.
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Gene expression from the new embryonic genome is required for normal preimplantation embryo development. Two members of the cAMP-responsive element-binding protein (Creb) family of transcription factors, Creb1 and activating transcription factor 1 (Atf1), are essential for normal preimplantation development. These transcription factors are activated by phosphorylation. Creb1 mRNA was expressed throughout the preimplantation phase. Cytoplasmic immunolocalization of Creb1 was detected in all preimplantation embryo stages. The antigen was largely excluded from the pronuclei/nuclei at embryonic stages except in the mid-cycle two-cell and compacted eight-cell embryo. Activation-state-specific antibodies showed serine 133 phosphorylated Creb1 localization was similar to Creb1 staining, except that there was no increase in staining at the eight-cell stage. Increased staining of phosphorylated Creb1 was observed in the nucleus of mid-cycle two-cell embryos. Increased expression of phosphorylated Creb1 in the two-cell embryo was induced by brief exposure of embryos to ionomycin, but not by a dibutyryl cAMP. This was blocked by buffering intracellular calcium with 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid tetrakis (acetoxymethyl ester), but not by a cAMP antagonist, Rp-cyclic 3′,5′-hydrogen phosphorothioate adenosine. Calmodulin is an intracellular receptor for calcium. Calmodulin mRNA was expressed throughout the preimplantation phase of development. The calmodulin antagonist, W-7, inhibited the ionomycin-induced localization of phosphorylated Creb1 in the nucleus. Treatment of embryos with W-7 caused a dose-dependent inhibition of normal development of zygotes to the blastocysts stage. The study shows Creb1 expression and nuclear localization was dynamically regulated in the early embryo. The marked nuclear accumulation and phosphorylation of Creb1 at the two-cell stage occurred at the time of transcription from the embryonic genome and was regulated in a calcium- and calmodulin-dependent manner.
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Ozsoy, S., M. B. Morris, and M. L. Day. "111. THE ROLE OF L-PROLINE IN PREIMPLANTATION MOUSE EMBRYO DEVELOPMENT IN VITRO." Reproduction, Fertility and Development 22, no. 9 (2010): 29. http://dx.doi.org/10.1071/srb10abs111.
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Amino acids are known to play important roles in preimplantation embryo development, including regulation of cell volume and metabolism. Inclusion of l-glutamine, glycine and betaine in embryo culture medium has been shown to improve development in vitro by acting as organic osmolytes, thereby regulating cell volume. The purpose of the present study was to examine the effect of l-proline on preimplantation mouse embryo development in vitro. One-cell stage embryos were cultured in modified HTF, at low density (1 embryo/100 μL) and high density (1 embryo/μL) in the presence and absence of amino acids. Development of the embryos was scored every 24 h until the blastocyst stage. At low density, l-proline significantly increased the proportion of embryos developing to the blastocyst stage. This effect was abolished by culture at high density, suggesting that l-proline was activating a pathway similar to that involved in autocrine signalling by trophic factors in the preimplantation embryo. The improvement in development observed in the presence of l-proline was not due to its action as an organic osmolyte since the osmolality of the medium was 270 mOsm. Furthermore, glycine and betaine, which are known to act as osmolytes in embryos, had no effect on blastocyst development. In embryonic stem cells L-proline is taken up by an amino acid transporter and is involved in the regulation of growth and differentiation (1). The present data suggest that l-proline may have a similar, important role in preimplantation development. (1) JM Washington, J Rathjen, F Felquer, A Lonic, MD Bettess, N Hamra, L Semendric, BSN Tan, J-A Lake, RA Keough, MB Morris and PD Rathjen (2010) Am J Physiol Cell Physiol 298: C982–C992.
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Jeremić, Ana, Dragana Vuković, Srna Subanović, Jovana Broćić, and Biljana Macanović. "Preimplantation genetic testing." Srpski medicinski casopis Lekarske komore 2, no. 2 (2021): 52–63. http://dx.doi.org/10.5937/smclk2-30790.
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The application of preimplantation genetic testing (PGT) began in the late 1980s. Pre-implantation genetic testing, as the earliest possible method of prenatal diagnosis, enables the selection of embryos with a normal karyotype for embryo transfer. The use of preimplantation genetic testing has proven to be a useful method in the following three groups of inherited diseases: monogenic disorders (single gene defects), trinucleotide repeat disorders, and chromosomal abnormalities. The success rate of in vitro fertilization (IVF) has increased significantly since the introduction of PGT into clinical practice. This paper presents a literature review with the aim of clearly determining the role of PGT in embryo selection before embryo transfer, as well as the role of this type of testing in increasing the success rate of IVF. One of the goals of the paper is also to review the development of molecular genetic methods that are currently, or have once been, in routine use when performing PGT. The current literature is an indicator of the development and progress of molecular genetics techniques applied in PGT. At the same time, it provides an opportunity and an incentive for further extensive research that will lead to the improvement of preimplantation genetic testing and thus increase the success rate of in vitro fertilization.
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Bjelica, Artur, and Srna Subanovic. "Assessment of the embryo quality in the procedure of in vitro fertilization." Medical review 69, no. 7-8 (2016): 241–46. http://dx.doi.org/10.2298/mpns1608241b.
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Introduction. Since reproductive technologies are becoming increasingly popular among the couples with infertility problem, and having in mind that the success rate is still low, the clinicians tend to transfer more embryos in order to increase the probability of success. However, such a strategy increases the risk of multiple pregnancy, which brings about numerous risks to the health of both the mother and children. Therefore, an elective single-embryo transfer is set as imperative, which, on the other hand, would not be possible without selection and evaluation of the quality of embryos. Assessment of Embryo Quality. Embryos can be selected by various methods, from non-invasive to invasive methods. In non-invasive methods, the embryos are selected by their morphology or by the techniques based on the analysis of molecular components - analyses of the level of proteomes or metabolomes. A more detailed monitoring of the kinetics of the embryo development can be related to the introduction of time-lapse imaging and monitoring systems into laboratory practice. The invasive methods encompass the techniques such as preimplantation genetic diagnosis and preimplantation genetic screening. In preimplantation genetic diagnosis, the assisted reproduction technologies cycle is approached for the genetic reasons, whereas preimplantation genetic screening is used to enhance the success rate of the assisted reproduction cycles. Conclusion. In this paper we have shown that the application of elective single-embryo transfer requires the selection and assessment of the quality of embryos by the methods that have been developed in the last four decades, and still need further improvements.
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Martin, Karen L., and Henry J. Leese. "Role of developmental factors in the switch from pyruvate to glucose as the major exogenous energy substrate in the preimplantation mouse embryo." Reproduction, Fertility and Development 11, no. 8 (1999): 425. http://dx.doi.org/10.1071/rd97071.
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Preimplantation mouse embryos, cultured in vitro and those freshly flushed from the reproductive tract, exhibit a switch in energy substrate preference, from pyruvate during the early preimplantation stages, to glucose at the blastocyst stage. Although the biochemical basis of this phenomenon is quite well characterized, its timing and possible association with developmental factors have not been considered. We have therefore examined the role of five developmental factors in determining the timing of the switch, namely: (1) embryo age (in hours post hCG); (2) developmental stage; (3) cytokinesis; (4) cell number; and (5) activation of the embryonic genome. One-cell embryos, which develop more slowly than 2-cell embryos in vitro, were used to investigate the role of embryo age and developmental stage. Cytochalasin D, which inhibits cytokinesis and delays the timing of compaction and cavitation, was used to investigate the role of cell division and developmental stage. Finally, transcription of the embryonic genome was examined with the inhibitor, α-amanitin. Pyruvate and glucose consumption by single embryos were measured using a non-invasive ultramicrofluorometric technique. The results showed that the timing of the switch in energy substrate preference is precisely regulated in the mouse preimplantation embryo. Activation of the embryonic genome is a prerequisite for the switch and its timing is closely associated with developmental stage, specifically compaction and/or cavitation. Cell number, cytokinesis and embryo age appeared to be unrelated to the timing of the switch. These conclusions may well be extrapolated to other species, since an increase in net glucose uptake, if not always at the expense of pyruvate, is a feature of preimplantation embryo metabolism in all mammals studied.
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Greco, Ermanno, Katarzyna Litwicka, Maria Giulia Minasi, Elisabetta Cursio, Pier Francesco Greco, and Paolo Barillari. "Preimplantation Genetic Testing: Where We Are Today." International Journal of Molecular Sciences 21, no. 12 (June 19, 2020): 4381. http://dx.doi.org/10.3390/ijms21124381.
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Background: Preimplantation genetic testing (PGT) is widely used today in in-vitro fertilization (IVF) centers over the world for selecting euploid embryos for transfer and to improve clinical outcomes in terms of embryo implantation, clinical pregnancy, and live birth rates. Methods: We report the current knowledge concerning these procedures and the results from different clinical indications in which PGT is commonly applied. Results: This paper illustrates different molecular techniques used for this purpose and the clinical significance of the different oocyte and embryo stage (polar bodies, cleavage embryo, and blastocyst) at which it is possible to perform sampling biopsies for PGT. Finally, genetic origin and clinical significance of embryo mosaicism are illustrated. Conclusions: The preimplantation genetic testing is a valid technique to evaluated embryo euploidy and mosaicism before transfer.
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Newmark, Judith A., William C. Warger II, ChihChing Chang, Gustavo E. Herrera, Dana H. Brooks, Charles A. DiMarzio, and Carol M. Warner. "Determination of the Number of Cells in Preimplantation Embryos by Using Noninvasive Optical Quadrature Microscopy in Conjunction with Differential Interference Contrast Microscopy." Microscopy and Microanalysis 13, no. 2 (February 15, 2007): 118–27. http://dx.doi.org/10.1017/s1431927607070171.
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The number of cells in a preimplantation embryo is directly correlated to the health and viability of the embryo. There are currently no methods to count the number of cells in late-stage preimplantation embryos noninvasively. We assessed the ability of optical quadrature microscopy (OQM) to count the number of cells in mouse preimplantation embryos noninvasively. First, to test for possible light toxicity, we exposed two-cell mouse embryos to OQM and differential interference contrast (DIC) microscopy and assessed their ability to develop to the blastocyst stage. We found no inhibition of development from either mode of microscopy for up to 2 h of light exposure. We also imaged eight-cell to morula stage mouse preimplantation embryos by OQM nd developed two methods for counting the number of cells. The contour signature method (CSM) used OQM images alone and the phase subtraction method (PSM) used both OQM and DIC images. We compared both methods to standard cell counting techniques and found that the PSM was superior to all other noninvasive cell counting methods. Our work on mouse embryos should be applicable to human embryos. The ability to correctly count the number of cells in human preimplantation embryos could lead to the transfer of fewer embryos in in vitro fertilization (IVF) clinics and consequently a lower rate of high-risk multiple-infant births.
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Vinijsanun, A., and L. Martin. "Effect of early ovariectomy and steroid hormone replacement of embryo transport, development and implantation in mice." Reproduction, Fertility and Development 3, no. 1 (1991): 35. http://dx.doi.org/10.1071/rd9910035.
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Bilateral ovariectomy on Day 1 of pregnancy increased abnormal embryo numbers on Day 4 and delayed passage of embryos to the uterus. Progestins given on Day 1 reversed these effects; given on Day 3 they reduced numbers of abnormal embryos, but did not restore normal transport. Oestrogen given alone after ovariectomy increased embryo loss, but restored preimplantation embryo development to normal when given on Day 3 after progestins on Day 1. The results suggested that both oestrogen and progesterone were necessary for normal preimplantation embryo development in vivo. However, although Day-1 progestins produced the greatest improvement in embryo transport and preimplantation development, they supported only low implantation rates compared with progestins starting on Day 3, and no progestin treatment returned implantation rates to normal. Sham ovariectomy on Day 1 also reduced implantation rate, suggesting that surgical stress of Day-1 ovariectomy had major adverse effects on embryo viability. This view was supported by experiments involving unilateral ovariectomy, which produced abnormalities in embryo transport, development and implantation, but only on the operated side. Furthermore, the major abnormality induced in embryo development by unilateral and bilateral ovariectomy, viz embryonic autolysis, was not increased in experiments in which pregnancy was blocked by non-surgical antagonism of progesterone. It is concluded that abnormalities in embryo development induced by early ovariectomy are not caused by a deficit of endogenous hormones, but result largely from effects of surgical trauma on oviduct function which can be reversed by treatment with exogenous hormones.
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Croteau, S., and Y. Menezo. "Methylation in fertilised and parthenogenetic preimplantation mouse embryos." Zygote 2, no. 1 (February 1994): 47–52. http://dx.doi.org/10.1017/s0967199400001751.
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SummaryDNA methylation is one of the proposed biochemical mechanisms involved in cell differentiation and in genomic imprinting, and DNA methyltransferase (DMT) is a key enzyme in the embryo since mutation of its gene is lethal early in development. In order to verify that non-viability of uniparental embryos was not due to a defect in the regulation of DMT activity, we compared the metabolism of methylation in parthenogenetic embryos (maternal genome) and in fertilised embryos (maternal and paternal genomes). As regards total methylation, estimated by a measure of S-adenosyl methionine (SAM) and S-adenosyl homocysteine (SAH) formation, no significant difference was found between the two kinds of embryos during preimplantation development. Mean values were 4.5 ± 0.6 fmol (SAM +SAH)/h per 2-cell embryo and 0.40 ± 0.05 fmol SAH/h per 2-cell embryo, i.e. a SAH/(SAM + SAH) ratio of 9%; there was no detectable SAH formation in blastocysts. The same observation can be made for DMT activity, with mean values of: 7.8 fmol/h per oocyte, 8.5 fmol/h per 2-cell embryo, 6.1 fmol/h per 4-cell embryo, 4.1 fmol/h per morula, and no detectable activity in blastocysts. Total methylation as well as DNA methylation is characterised by a progressive drop in activity during preimplantation development.
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Treleaven, Tamara, Matthew Zada, Rajini Nagarajah, Charles G. Bailey, John E. J. Rasko, Michael B. Morris, and Margot L. Day. "Stage-Specific L-Proline Uptake by Amino Acid Transporter Slc6a19/B0AT1 Is Required for Optimal Preimplantation Embryo Development in Mice." Cells 12, no. 1 (December 21, 2022): 18. http://dx.doi.org/10.3390/cells12010018.
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L-proline (Pro) has previously been shown to support normal development of mouse embryos. Recently we have shown that Pro improves subsequent embryo development when added to fertilisation medium during in vitro fertilisation of mouse oocytes. The mechanisms by which Pro improves embryo development are still being elucidated but likely involve signalling pathways that have been observed in Pro-mediated differentiation of mouse embryonic stem cells. In this study, we show that B0AT1, a neutral amino acid transporter that accepts Pro, is expressed in mouse preimplantation embryos, along with the accessory protein ACE2. B0AT1 knockout (Slc6a19−/−) mice have decreased fertility, in terms of litter size and preimplantation embryo development in vitro. In embryos from wild-type (WT) mice, excess unlabelled Pro inhibited radiolabelled Pro uptake in oocytes and 4–8-cell stage embryos. Radiolabelled Pro uptake was reduced in 4–8-cell stage embryos, but not in oocytes, from Slc6a19−/− mice compared to those from WT mice. Other B0AT1 substrates, such as alanine and leucine, reduced uptake of Pro in WT but not in B0AT1 knockout embryos. Addition of Pro to culture medium improved embryo development. In WT embryos, Pro increased development to the cavitation stage (on day 4); whereas in B0AT1 knockout embryos Pro improved development to the 5–8-cell (day 3) and blastocyst stages (day 6) but not at cavitation (day 4), suggesting B0AT1 is the main contributor to Pro uptake on day 4 of development. Our results highlight transporter redundancy in the preimplantation embryo.
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Harper, Joyce C. "Preimplantation genetic screening." Journal of Medical Screening 25, no. 1 (June 14, 2017): 1–5. http://dx.doi.org/10.1177/0969141317691797.
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Preimplantation genetic diagnosis was first successfully performed in 1989 as an alternative to prenatal diagnosis for couples at risk of transmitting a genetic or chromosomal abnormality, such as cystic fibrosis, to their child. From embryos generated in vitro, biopsied cells are genetically tested. From the mid-1990s, this technology has been employed as an embryo selection tool for patients undergoing in vitro fertilisation, screening as many chromosomes as possible, in the hope that selecting chromosomally normal embryos will lead to higher implantation and decreased miscarriage rates. This procedure, preimplantation genetic screening, was initially performed using fluorescent in situ hybridisation, but 11 randomised controlled trials of screening using this technique showed no improvement in in vitro fertilisation delivery rates. Progress in genetic testing has led to the introduction of array comparative genomic hybridisation, quantitative polymerase chain reaction, and next generation sequencing for preimplantation genetic screening, and three small randomised controlled trials of preimplantation genetic screening using these new techniques indicate a modest benefit. Other trials are still in progress but, regardless of their results, preimplantation genetic screening is now being offered globally. In the near future, it is likely that sequencing will be used to screen the full genetic code of the embryo.
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Hansen, Peter J., and Paula Tríbulo. "Regulation of present and future development by maternal regulatory signals acting on the embryo during the morula to blastocyst transition – insights from the cow." Biology of Reproduction 101, no. 3 (February 19, 2019): 526–37. http://dx.doi.org/10.1093/biolre/ioz030.
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Abstract The preimplantation embryo has a remarkable ability to execute its developmental program using regulatory information inherent within itself. Nonetheless, the uterine environment is rich in cell signaling molecules termed embryokines that act on the embryo during the morula-to-blastocyst transition, promoting blastocyst formation and programming the embryo for subsequent developmental events. Programming can not only affect developmental processes important for continuance of development in utero but also affect characteristics of the offspring during postnatal life. Given the importance of embryokines for regulation of embryonic development, it is likely that some causes of infertility involve aberrant secretion of embryokines by the uterus. Embryokines found to regulate development of the bovine embryo include insulin-like growth factor 1, colony stimulating factor 2 (CSF2), and dickkopf WNT signaling pathway inhibitor 1. Embryo responses to CSF2 exhibit sexual dimorphism, suggesting that sex-specific programming of postnatal function is caused by maternal signals acting on the embryo during the preimplantation period that regulate male embryos differently than female embryos.
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Guérin, Pierre, and Yves Ménézo. "Review: Role of tubal environment in preimplantation embryogenesis: application to co-culture assays." Zygote 19, no. 1 (July 13, 2010): 47–54. http://dx.doi.org/10.1017/s0967199410000092.
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SummaryThe culture of early preimplantation stage embryo is still delicate and the metabolic pathways of embryos are not completely understood. Embryo needs are evolutionary during the preimplantation development, consequently it is difficult to meet embryo needs in vitro. Culture conditions have to respect several physical and chemical equilibria: such as redox potential, pH, osmotic pressure, metabolic flux of energetic compounds, endogenous pools of amino acids and transcripts, etc. Embryo culture media are generally supplemented with amino acids, glucose, other energetic metabolites and antioxidant compounds, vitamin, and growth factors etc. Furthermore autocrine and paracrine regulation of embryo development probably exist. In fact embryo culture conditions have to be as non-toxic as possible. Various types of co-culture systems have been devised to overcome these problems. Complex interrelations exist between embryos and co-cultured cells. The beneficial effects of co-cultured cells may be due to continuous modifications of the culture medium, i.e. the elimination of toxic compounds and/or the supply of embryotrophic factors.
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Fair, T., A. Gutierrez-Adan, M. Murphy, D. Rizos, F. Martin, M. P. Boland, and P. Lonergan. "232SEARCH FOR THE BOVINE HOMOLOG OF THE MURINE PED GENE." Reproduction, Fertility and Development 16, no. 2 (2004): 237. http://dx.doi.org/10.1071/rdv16n1ab232.
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The aim of the current study was to identify the bovine homolog of the murine Ped (preimplantation embryo development) gene, which regulates mouse preimplantation embryonic growth, including cleavage rate and embryo survivability, and to characterize the expression pattern of this gene during bovine preimplantation embryo development. Experiment (I): The National Center for Biotechnology Information (NCBI) GenBank/EBI EST databases were searched for bovine-expressed sequence tags (EST) that were homologous with the murine Ped gene (Accession number: NM_010394). The resulting ESTs were aligned and assembled in to one complete sequence (841bp), which was shown to be homologous with the Murine Ped gene and the Bovine Major Histocompatibility Complex class I 4221.1 gene (Accession No.: AJ010865, length 1090bp). The expression of the protein product of the Ped gene by bovine tissue was confirmed using Western Blot analysis. Experiment (II): The expression pattern of the Ped gene homolog during in vivo and in vitro bovine preimplantation embryo development was characterized using real time PCR. Embryos at the same stage for age were compared (Day 1: 2-cell; Day 2: 4-cell; Day 3: 8-cell; Day 4: 16-cell; Day 5: early morula;; Day 6, compact/late morula;; Day 7: blastocyst). The relative transcript abundance was consistently lower in the in vitro-cultured embryos at all stages of preimplantation development the differences were significant on Days 2, 4, 5, 6, and 7. The relative transcript abundance was significantly lower on Days 1, 2, and 3 of in vivo culture than on Days 4, 5, 6, and 7 and was significantly higher in Day 7 blastocysts than in Day 5 early morula. In in vitro-cultured embryos the relative transcript abundance was significantly higher in Day 7 blastocysts compared to all other stages of the preimplantation period. Experiment (III): A quantitative analysis of the Ped gene homolog was carried out on replicates of pools of ten 2-cell embryos collected at 25, 28, 32, and >36hpi from three different fertilizations. Transcript relative abundance was highest in those embryos that had cleaved by 25hpi. By 28hpi abundance had decreased slightly;; as time to cleavage increased further to 32 and >36hpi, the relative abundance decreased significantly. In conclusion, we have successfully identified a potential bovine homolog of the murine Ped gene. Furthermore, we have characterized the expression pattern of this gene during preimplantation embryo development in cattle and we have shown that a greater relative abundance of the gene transcript is associated with embryos of higher quality and greater developmental potential.
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Bodó, S., B. Baranyai, Elen Gócza, J. Dohy, and Merja Markkula. "Preimplantation genetic diagnosis in cattle: A review." Acta Veterinaria Hungarica 49, no. 1 (January 2001): 99–109. http://dx.doi.org/10.1556/004.49.2001.1.12.
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Preimplantation Genetic Diagnosis (PGD) is reviewed and novel fields where it may be applied are investigated. Technical advances of PGD in cattle embryos have already enabled its integration as a part of the MOET (Multiple Ovulation Embryo Transfer) breeding system. PGD for well-defined selection targets can enhance cattle breeding and embryo trade. It allows embryo selection according to their sex, and it may be used to breed special cow lines, or top bulls, by selecting embryos for valuable production traits using Marker Assisted Selection (MAS). A good allelic profile and/or the insertion of a transgene can be detected by PGD. This review article presents the technical requirements for PGD, and shows that this biotechnological method has great economic potential.
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Longcope, Christopher. "The Mammalian Preimplantation Embryo." Endocrinologist 3, no. 3 (May 1993): 225. http://dx.doi.org/10.1097/00019616-199305000-00009.
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Stewart, Jane A. "Human Preimplantation Embryo Selection." Obstetrician & Gynaecologist 10, no. 4 (October 2008): 280. http://dx.doi.org/10.1576/toag.10.4.280a.27452.
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Trimarchi, James R., Lin Liu, D. Marshal Porterfield, Peter J. S. Smith, and David L. Keefe. "A non-invasive method for measuring preimplantation embryo physiology." Zygote 8, no. 1 (February 2000): 15–24. http://dx.doi.org/10.1017/s0967199400000782.
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The physiology of the early embryo may be indicative of embryo vitality and therefore methods for non-invasively monitoring physiological parameters from embryos could improve preimplantation diagnoses. The self-referencing electrophysiological technique is capable of non-invasive measurement of the physiology of individual cells by monitoring the movement of ions and molecules between the cell and the surrounding media. Here we use this technique to monitor gradients of calcium, potassium, oxygen and hydrogen peroxide around individual mouse preimplantation embryos. The calcium-sensitive electrode in self-referencing mode identified a region of elevated calcium concentration (∼0.25 pmol) surrounding each embryo. The calcium gradient surrounding embryos was relatively steep, such that the region of elevated calcium extended into the medium only 4 μm from the embryo. By contrast, using an oxygen-sensitive electrode an extensive gradient of reduced dissolved oxygen concentration was measured surrounding the embryo and extended tens of micrometres into the medium. A gradient of neither potassium nor hydrogen peroxide was observed around unperturbed embryos. We also demonstrate that monitoring the physiology of embryos using the self-referencing technique does not compromise their subsequent development. Blastocysts studied with the self-referencing technique implanted and developed to term at the same frequency as did unexamined, control embryos. Therefore, the self-referencing electrode provides a valuable non-invasive technique for studying the physiology and pathophysiology of individual embryos without hindering their subsequent development.
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Kim, B. K., H. J. Chung, B. C. Yang, D. H. Kim, J. H. Woo, J. H. Choi, H. H. Seong, J. K. Jung, and W. K. Chang. "153EXPRESSION OF TGF-BETA I AND TYPE I AND TYPE II OF TGF-BETA RECEPTORS IN BOVINE EMBRYOS." Reproduction, Fertility and Development 16, no. 2 (2004): 198. http://dx.doi.org/10.1071/rdv16n1ab153.
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Although the effects of TGFβ1, as an important factor in the mice embryo development have been reported, little information relevant to this subject is known in the bovine embryo. The objectives of this study were to investigate the presence and expression patterns of TGFβ1 and TGFβ1 receptors, types I and II, in unfertilized oocytes and fertilized bovine embryos in normal and NT embryo development. We postulated that TGFβ1 may have a beneficial effect on the preimplantation embryo and show different expression patterns at different stages of bovine embryo development. Immature bovine oocytes were aspirated from follicles of ovaries obtained from a local abattoir and they were cultured for up to 24h and fertilized in vitro. Reverse transcription-polymerase chain reaction (RT-PCR) and immunocytochemistry were used to investigate the presence of TGFβ1 and type I and type II of TGFβ1 receptors (the essential components of the TGFβ1 signaling pathway) in unfertilized oocytes and preimplantation embryos. Also, mRNA and protein expression patterns of TGFβ1 and their receptors at various stages of embryos were examined. It was found that both receptors, as well as TGFβ1, were present in the unfertilized bovine oocytes, indicating that TGFβ1 is a maternally expressed protein. Although the type I TGFβ1 receptor was present at the morulae and blastocyst stages, the type II TGFβ1 receptor was not present at both stages. It was also confirmed that the expression level of TGFβ1 was high at the 8-cell stage, and mRNA and protein expression patterns of TGFβ1 and their receptors were not coincident. Interestingly, TGFβ1 protein was not detected at blastocyst stage of embryos, whereas the mRNA expression level was high at this stage. The results of this experiment indicate that TGFβ1 protein may be needed by embryos after the blastocyst stage and may be expressed in hatched embryos for implantation. These findings support the hypothesis that there may be an interaction between the TGFβ1 and TGFβ1 receptors in the unfertilized oocytes and preimplantation embryos, and that TGFβ1 signaling may be important for the development of the oocytes and the preimplantation embryos.
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Karasek, Challis, Mohamed Ashry, Chad S. Driscoll, and Jason G. Knott. "A tale of two cell-fates: role of the Hippo signaling pathway and transcription factors in early lineage formation in mouse preimplantation embryos." Molecular Human Reproduction 26, no. 9 (July 9, 2020): 653–64. http://dx.doi.org/10.1093/molehr/gaaa052.
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Abstract In mammals, the first cell-fate decision occurs during preimplantation embryo development when the inner cell mass (ICM) and trophectoderm (TE) lineages are established. The ICM develops into the embryo proper, while the TE lineage forms the placenta. The underlying molecular mechanisms that govern lineage formation involve cell-to-cell interactions, cell polarization, cell signaling and transcriptional regulation. In this review, we will discuss the current understanding regarding the cellular and molecular events that regulate lineage formation in mouse preimplantation embryos with an emphasis on cell polarity and the Hippo signaling pathway. Moreover, we will provide an overview on some of the molecular tools that are used to manipulate the Hippo pathway and study cell-fate decisions in early embryos. Lastly, we will provide exciting future perspectives on transcriptional regulatory mechanisms that modulate the activity of the Hippo pathway in preimplantation embryos to ensure robust lineage segregation.
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Čikoš, Štefan, Pavol Rehák, Soňa Czikková, Jarmila Veselá, and Juraj Koppel. "Expression of adrenergic receptors in mouse preimplantation embryos and ovulated oocytes." Reproduction 133, no. 6 (June 2007): 1139–47. http://dx.doi.org/10.1530/rep-07-0006.
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Epinephrine and norepinephrine can play an important role in basic developmental processes such as embryogenesis and morphogenesis, regulating cell proliferation, differentiation and migration. We showed that β-adrenergic receptors can mediate the effects of catecholamines on preimplantation embryos in our previous work. In the present study, we designed specific oligonucleotide primers which can distinguish among all members of the α-adrenergic receptor family, and showed (using RT-PCR) that the α2C-adrenergic receptor is transcribed in ovulated oocytes, 8- to 16-cell morulae and expanded blastocysts. We did not detect the α2C-adrenoceptor transcript in 4-cell embryos. Our immunohistochemical study showed the presence of α-2C-adrenoceptor protein in ovulated oocytes, 8- to 16- cell embryos and blastocysts, but the signal in 4-cell embryos was weak, and probably represents remaining protein of maternal origin. We did not detect any other α-adrenergic receptor in preimplantation embryos and oocytes. Exposure of mouse preimplantation embryos to the α2-adrenergic agonist UK 14 304 led to significant reduction of the embryo cell number, and the effect was dose dependent. Our results suggest that epinephrine and norepinephrine could affect the embryo development in the oviduct via adrenergic receptors directly and support the opinion that maternal stress can influence the embryo even in very early pregnancy.
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Sharma, Jyoti, and Pavneesh Madan. "Characterisation of the Hippo signalling pathway during bovine preimplantation embryo development." Reproduction, Fertility and Development 32, no. 4 (2020): 392. http://dx.doi.org/10.1071/rd18320.
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Blastocyst formation is an important milestone during preimplantation embryo development. During murine preimplantation embryogenesis, the Hippo signalling pathway is known to play a significant role in lineage segregation and henceforth the formation of blastocysts. However, the role of this cell signalling pathway during bovine embryogenesis remains unknown. Thus, the aim of the present study was to characterise the Hippo signalling pathway during bovine preimplantation embryo development. mRNA transcripts of Hippo signalling pathway constituents (i.e. crumbs cell polarity complex component 3 (CRB3), mammalian sterile 20-like 1 (MST1), mammalian sterile 20-like 2 (MST2), Yes associated protein 1 (YAP1), transcriptional coactivator with PDZ-binding motif (TAZ)) were observed during all stages of bovine preimplantation embryo development. To evaluate the localisation of Hippo pathway components, bovine embryos at timed stages of development were stained using specific antibodies and observed under a laser confocal microscope. Although MST1/2 proteins were in the cytoplasm during various stages of bovine embryonic development, TAZ and phosphorylated (p-) YAP were detected in the nucleus during the blastocyst stages. Localisation of TAZ and p-YAP proteins was distinct in the bovine compared with mouse model, suggesting that the Hippo signalling pathway is regulated differently in early bovine embryos.
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Nõmm, Monika, Marilin Ivask, Pille Pärn, Ene Reimann, Sulev Kõks, and Ülle Jaakma. "Detecting Embryo Developmental Potential by Single Blastomere RNA-Seq." Genes 14, no. 3 (February 24, 2023): 569. http://dx.doi.org/10.3390/genes14030569.
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Recent advances in preimplantation embryo diagnostics enable a wide range of applications using single cell biopsy and molecular-based selection techniques without compromising embryo production. This study was conducted to develop a single cell embryo biopsy technique and gene expression analysis method with a very low input volume to ensure normal embryo development and to see if there are differences in gene expression profiles between day-5 biopsied bovine embryos that developed into blastocysts and embryos arrested at morula stage. Out of the 65 biopsied morulae, 32 developed to blastocysts (49.2%). Out of the 13,580 successfully annotated genes, 1204 showed a difference in mRNA expression level. Out of these, 155 genes were expressed in embryos developing to blastocysts. The pathway enrichment analysis revealed significant enrichment in “organelle biogenesis and maintenance”, “mRNA splicing” and “mitochondrial translation” pathways. These findings suggest principal differences in gene expression patterns and functional networks of embryos able to reach the blastocyst stage compared to embryos arrested in development. Our preliminary data suggest that single blastomere biopsy and selected gene expression profiles at morula stage could offer additional possibilities for early preimplantation embryo selection before transfer.
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Heffernan, Corey, Penny A. F. Whiley, Antonia Milionis, Paul J. Verma, Michael K. Holland, David A. Jans, and Nancy T. D'Cruz. "Lineage-specific expression of heterochromatin protein 1γ in post-compaction, in vitro-produced bovine embryos." Reproduction, Fertility and Development 22, no. 6 (2010): 1022. http://dx.doi.org/10.1071/rd09265.
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Heterochromatin protein 1γ (HP1γ) is a highly conserved regulator of euchromatic and heterochromatic gene expression. Mammalian HP1γ is essential for both successful preimplantation embryo development and maintenance of pluripotency in embryonic stem cells in vitro. Here, we describe HP1γ protein localisation in matured (MII) bovine oocytes and IVF preimplantation embryos at defined developmental stages. HP1γ is expressed in post-compaction embryos in a highly lineage-specific pattern. In embryonic stages preceding the maternal to embryonic transition (MET), HP1γ protein was primarily cytoplasmic, whereas in 8–16-cell embryos (post MET), HP1γ was primarily nuclear. Lineage-specific patterns of HP1γ protein localisation become evident from compaction, being restricted to peripheral, extraembryonic cells at the morula and blastocyst stages (Days 7–9). Surprisingly, we detected HP1γ mRNA in both embryonic and extraembryonic cells in blastocysts by fluorescence in situ hybridisation. In trophectoderm cells, HP1γ protein was localised in specific patterns at the mitotic and interphase stages of the cell cycle. These results demonstrate lineage- and cell cycle-specific patterns of HP1γ protein localisation in the post-compaction, preimplantation bovine embryo and raise interesting questions about the role of HP1γ in early embryo development.
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Tomic, Maja, Eda Vrtacnik Bokal, and Martin Stimpfel. "Non-Invasive Preimplantation Genetic Testing for Aneuploidy and the Mystery of Genetic Material: A Review Article." International Journal of Molecular Sciences 23, no. 7 (March 25, 2022): 3568. http://dx.doi.org/10.3390/ijms23073568.
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This review focuses on recent findings in the preimplantation genetic testing (PGT) of embryos. Different preimplantation genetic tests are presented along with different genetic materials and their analysis. Original material concerning preimplantation genetic testing for aneuploidy (PGT-A) was sourced by searching the PubMed and ScienceDirect databases in October and November 2021. The searches comprised keywords such as ‘preimplantation’, ‘cfDNA’; ‘miRNA’, ‘PGT-A’, ‘niPGT-A’, ‘aneuploidy’, ‘mosaicism’, ‘blastocyst biopsy’, ‘blastocentesis’, ‘blastocoel fluid’, ‘NGS’, ‘FISH’, and ‘aCGH’. Non-invasive PGT-A (niPGT-A) is a novel approach to the genetic analysis of embryos. The premise is that the genetic material in the spent embryo culture media (SECM) corresponds to the genetic material in the embryo cells. The limitations of niPGT-A are a lower quantity and lesser quality of the cell-free genetic material, and its unknown origin. The concordance rate varies when compared to invasive PGT-A. Some authors have also hypothesized that mosaicism and aneuploid cells are preferentially excluded from the embryo during early development. Cell-free genetic material is readily available in the spent embryo culture media, which provides an easier, more economic, and safer extraction of genetic material for analysis. The sampling of the SECM and DNA extraction and amplification must be optimized. The origin of the cell-free media, the percentage of apoptotic events, and the levels of DNA contamination are currently unknown; these topics need to be further investigated.
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Lilao-Garzón, Joaquín, Yeray Brito-Casillas, Oscar Quesada-Canales, Ana M. Wägner, and Silvia Muñoz-Descalzo. "Maternal age, obesity and hyperglycaemia are associated with a delay in preimplantation embryo development in mouse." Reproduction 166, no. 3 (July 18, 2023): 235–45. http://dx.doi.org/10.1530/rep-23-0024.
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In brief Fertility has decreased due to advanced maternal age and the rising prevalence of the metabolic syndrome. Using quantitative image analysis methods, we show that these factors are associated with delayed preimplantation embryo development in a mouse model. Abstract Delayed maternal age, obesity and diabetes are associated with reduced fertility. We investigated how age and obesity/metabolic syndrome impact fertility and hypothesized that its decrease is due to defects in preimplantation embryo development. Three groups of female C57Bl6 mice (12 weeks, 9 months and 1 year old) were fed either a high-fat diet for 8 weeks, to induce obesity and the metabolic syndrome, or a control chow diet. Body weight and composition, glucose tolerance and insulin resistance were assessed. Fecundity was evaluated by mating and pregnancy rates, as well as by the number of embryos. Embryo quality was assessed morphologically, and cell fate composition was analysed in preimplantation embryos by state-of-the-art single-cell quantitative confocal image analysis. The high-fat diet was associated with increased adiposity, glucose intolerance and insulin resistance, especially in the older mice. Fecundity was affected by age more than by the diet. Both age and high-fat diet were associated with reduced cell fate allocation, indicating a delay in the preimplantation embryo development, and with increased expression of GATA3, an inhibitor of placentation. These results support that age and the metabolic syndrome reduce fertility through mechanisms which are present at conception or very early in pregnancy.
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Bianco, Bianca, Denise Maria Christofolini, Gabriel Seixas Conceição, and Caio Parente Barbosa. "Preimplantation genetic diagnosis associated to Duchenne muscular dystrophy." Einstein (São Paulo) 15, no. 4 (September 21, 2017): 489–91. http://dx.doi.org/10.1590/s1679-45082017rc3994.
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ABSTRACT Duchenne muscular dystrophy is the most common muscle disease found in male children. Currently, there is no effective therapy available for Duchenne muscular dystrophy patients. Therefore, it is essential to make a prenatal diagnosis and provide genetic counseling to reduce the birth of such boys. We report a case of preimplantation genetic diagnosis associated with Duchenne muscular dystrophy. The couple E.P.R., 38-year-old, symptomatic patient heterozygous for a 2 to 47 exon deletion mutation in DMD gene and G.T.S., 39-year-old, sought genetic counseling about preimplantation genetic diagnosis process. They have had a 6-year-old son who died due to Duchenne muscular dystrophy complications. The couple underwent four cycles of intracytoplasmic sperm injection (ICSI) and eight embryos biopsies were analyzed by polymerase chain reaction (PCR) for specific mutation analysis, followed by microarray-based comparative genomic hybridisation (array CGH) for aneuploidy analysis. Preimplantation genetic diagnosis revealed that two embryos had inherited the maternal DMD gene mutation, one embryo had a chromosomal alteration and five embryos were normal. One blastocyst was transferred and resulted in successful pregnancy. The other embryos remain vitrified. We concluded that embryo analysis using associated techniques of PCR and array CGH seems to be safe for embryo selection in cases of X-linked disorders, such as Duchenne muscular dystrophy.
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Lee, Kai-Fai, Jia-Sen Xu, Yin-Lau Lee, and William S. B. Yeung. "Demilune Cell and Parotid Protein from Murine Oviductal Epithelium Stimulates Preimplantation Embryo Development." Endocrinology 147, no. 1 (January 1, 2006): 79–87. http://dx.doi.org/10.1210/en.2005-0596.
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In mammals, fertilization and early preimplantation embryo development occur in the oviduct. We hypothesized that interaction exists between the developing embryos and the maternal genital tract, such that the embryos modulate the physiology and gene expression of the oviduct so that it is conducive to their development. By comparing the gene expression patterns in mouse oviducts containing transferred preimplantation embryos with those of oviducts containing oocytes, we report here the characterization of demilune cell and parotid protein (Dcpp), which was up-regulated in the embryo-containing oviduct. Dcpp mRNA was highly expressed in the oviductal epithelium at the estrus stage. The Dcpp gene codes for a protein of 150 amino acids and contains a signal peptide suggestive of secretory function. The Dcpp mRNA level was maintained in the oviductal epithelium of pregnant females but decreased continuously in those of pseudopregnant mice. Exogenous estrogen stimulated the expression of Dcpp mRNA and protein in ovariectomized mice. The effect was abolished by an estrogen antagonist, ICI 182,780. Dcpp protein was present in mouse oviductal fluid but not in uterine fluid. More importantly, Dcpp immunoreactivity was found in embryos recovered from the oviduct but not in mature oocytes from the ovary. Supplementation of Dcpp to culture medium stimulated the development of mouse embryos to the blastocyst stage. Anti-Dcpp antibody decreased the beneficial effect of Dcpp on implantation of two-cell mouse embryos transferred to the oviducts of the foster mothers. In summary, our data demonstrated that Dcpp is highly expressed in the oviductal lumen in the presence of preimplantation embryos. It stimulates the growth of preimplantation embryos and may play an important role in embryo-maternal dialogue.
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Kuşcu, Nilay, Mariano Bizzarri, and Arturo Bevilacqua. "Myo-Inositol Safety in Pregnancy: From Preimplantation Development to Newborn Animals." International Journal of Endocrinology 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/2413857.
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Myo-inositol (myo-Ins) has a physiological role in mammalian gametogenesis and embryonic development and a positive clinical impact on human medically assisted reproduction. We have previously shown that mouse embryo exposure to myo-Ins through preimplantation developmentin vitroincreases proliferation activity and blastocyst production, representing an improvement in culture conditions. We have herein investigated biochemical mechanisms elicited by myo-Ins in preimplantation embryos and evaluated myo-Ins effects on postimplantation/postnatal development. To this end naturally fertilized embryos were culturedin vitroto blastocyst in the presence or absence of myo-Ins and analyzed for activation of the PKB/Akt pathway, known to modulate proliferation/survival cellular processes. In parallel, blastocyst-stage embryos were transferred into pseudopregnant females and allowed to develop to term and until weaning. Results obtained provide evidence that myo-Ins induces cellular pathways involving Akt and show that (a) exposure of preimplantation embryos to myo-Ins increases the number of blastocysts available for uterine transfer and of delivered animals and (b) the developmental patterns of mice obtained from embryos cultured in the presence or absence of myo-Ins, up to three weeks of age, overlap. These data further identify myo-Ins as a possibly important supplement for human preimplantation embryo culture in assisted reproduction technology.
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Pavani, Krishna C., Carmen Alminana, Eline Wydooghe, Maaike Catteeuw, Miguel A. Ramírez, Pascal Mermillod, Dimitrios Rizos, and Ann Van Soom. "Emerging role of extracellular vesicles in communication of preimplantation embryos in vitro." Reproduction, Fertility and Development 29, no. 1 (2017): 66. http://dx.doi.org/10.1071/rd16318.
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In vitro, efficient communication between mammalian embryos in groups or between embryos and cocultured somatic cells implies that there is a sender, a message and a receiver that is able to decode the message. Embryos secrete a variety of autocrine and paracrine factors and, of these, extracellular vesicles have recently been implicated as putative messengers in embryo–embryo communication, as well as in communication of the embryo with the maternal tract. Extracellular vesicles (EVs) are membrane-bound vesicles that are found in biofluids and in culture media conditioned by the presence of embryos or cells. EVs carry and transfer regulatory molecules, such as microRNAs, mRNAs, lipids and proteins. We conducted a systematic search of the literature to review and present the currently available evidence regarding the possible roles of EVs in in vitro embryo communication and embryo development. It is important to note that there is limited information available on the molecular mechanisms and many of the biologically plausible functions of EVs in embryo communication have not yet been substantiated by conclusive experimental evidence. However, indirect evidence, such as the use of media conditioned by embryos or by somatic cells with improved embryo development as a result, may indicate that EVs can be an important asset for the development of tailor-made media, allowing better embryo development in vitro, even for single embryo culture.
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Calder, Michele D., Patricia H. Watson, and Andrew J. Watson. "Culture medium, gas atmosphere and MAPK inhibition affect regulation of RNA-binding protein targets during mouse preimplantation development." REPRODUCTION 142, no. 5 (November 2011): 689–98. http://dx.doi.org/10.1530/rep-11-0082.
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During oogenesis, mammalian oocytes accumulate maternal mRNAs that support the embryo until embryonic genome activation. RNA-binding proteins (RBP) may regulate the stability and turnover of maternal and embryonic mRNAs. We hypothesised that varying embryo culture conditions, such as culture medium, oxygen tension and MAPK inhibition, affects regulation of RBPs and their targets during preimplantation development. STAU1, ELAVL1, KHSRP and ZFP36 proteins and mRNAs were detected throughout mouse preimplantation development, whereasElavl2mRNA decreased after the two-cell stage. Potential target mRNAs of RBP regulation,Gclc,Slc2a1andSlc7a1were detected during mouse preimplantation development.GclcmRNA was significantly elevated in embryos cultured in Whitten's medium compared with embryos cultured in KSOMaa, andGclcmRNA was elevated under high-oxygen conditions. Inhibition of the p38 MAPK pathway reducedSlc7a1mRNA expression while inhibition of ERK increasedSlc2a1mRNA expression. The half-lives of the potential RBP mRNA targets are not regulated in parallel;Slc2a1mRNA displayed the longest half-life. Our results indicate that mRNAs and proteins encoding five RBPs are present during preimplantation development and more importantly, demonstrate that expression of RBP target mRNAs are regulated by culture medium, gas atmosphere and MAPK pathways.
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Schultz, GA, A. Hogan, AJ Watson, RM Smith, and S. Heyner. "Insulin, insulin-like growth factors and glucose transporters: temporal patterns of gene expression in early murine and bovine embryos." Reproduction, Fertility and Development 4, no. 4 (1992): 361. http://dx.doi.org/10.1071/rd9920361.
Full textAbstract:
mRNA phenotyping by the reverse transcription-polymerase chain reaction (RT-PCR) method was used to compare the patterns of expression of insulin and insulin-like growth factor (IGF) ligand and receptor genes in preimplantation bovine embryos with those established previously for preimplantation murine embryos. In the early bovine embryo, transcripts for IGF-I, IGF-II and mRNAs encoding receptors for insulin, IGF-I and IGF-II were all detectable at all embryo stages from the 1-cell zygote to the blastocyst. In the mouse, IGF-II ligand and receptor mRNAs were not expressed until the 2-cell stage, and the insulin and IGF-I receptor mRNAs were not detectable until the 8-cell stage. Since transcriptional activation of the embryonic genome occurs at the 8- to 16-cell stage in the bovine embryo and at the 2-cell stage in the murine embryo, it is suggested that these transcripts are products of both the maternal and embryonic genomes in the bovine embryo whereas in the mouse they are present only after activation of the embryonic genome. Transcripts for insulin were not detected in preimplantation embryos of either species. Colloidal-gold immunocytochemistry with antibodies directed against the insulin receptor, IGF-I receptor and IGF-I ligand has confirmed the presence of these molecules in bovine blastocysts. RT-PCR and indirect immunofluorescence procedures demonstrated that the glucose transporter (GLUT) isoform 1 is present in murine embryos from the oocyte to blastocyst stage whereas GLUT 2 expression begins at the 8-cell stage.
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Simon, Blanca, David Bolumar, Alicia Amadoz, Jorge Jimenez-Almazán, Diana Valbuena, Felipe Vilella, and Inmaculada Moreno. "Identification and Characterization of Extracellular Vesicles and Its DNA Cargo Secreted During Murine Embryo Development." Genes 11, no. 2 (February 17, 2020): 203. http://dx.doi.org/10.3390/genes11020203.
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Extracellular vesicles (EVs) are known to transport DNA, but their implications in embryonic implantation are unknown. The aim of this study was to investigate EVs production and secretion by preimplantation embryos and assess their DNA cargo. Murine oocytes and embryos were obtained from six- to eight-week-old females, cultured until E4.5 and analyzed using transmission electron microscopy to examine EVs production. EVs were isolated from E4.5-day conditioned media and quantified by nanoparticle tracking analysis, characterized by immunogold, and their DNA cargo sequenced. Multivesicular bodies were observed in murine oocytes and preimplantation embryos together with the secretion of EVs to the blastocoel cavity and blastocyst spent medium. Embryo-derived EVs showed variable electron-densities and sizes (20–500 nm) and total concentrations of 1.74 × 107 ± 2.60 × 106 particles/mL. Embryo secreted EVs were positive for CD63 and ARF6. DNA cargo sequencing demonstrated no differences in DNA between apoptotic bodies or smaller EVs, although they showed significant gene enrichment compared to control medium. The analysis of sequences uniquely mapping the murine genome revealed that DNA contained in EVs showed higher representation of embryo genome than vesicle-free DNA. Murine blastocysts secrete EVs containing genome-wide sequences of DNA to the medium, reinforcing the relevance of studying these vesicles and their cargo in the preimplantation moment, where secreted DNA may help the assessment of the embryo previous to implantation.
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Hawke, David C., Andrew J. Watson, and Dean H. Betts. "Selecting Normalizers for MicroRNA RT-qPCR Expression Analysis in Murine Preimplantation Embryos and the Associated Conditioned Culture Media." Journal of Developmental Biology 11, no. 2 (April 4, 2023): 17. http://dx.doi.org/10.3390/jdb11020017.
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Normalizing RT-qPCR miRNA datasets that encompass numerous preimplantation embryo stages requires the identification of miRNAs that may be used as stable reference genes. A need has also arisen for the normalization of the accompanying conditioned culture media as extracellular miRNAs may serve as biomarkers of embryo developmental competence. Here, we evaluate the stability of six commonly used miRNA normalization candidates, as well as small nuclear U6, using five different means of evaluation (BestKeeper, NormFinder, geNorm, the comparative Delta Ct method and RefFinder comprehensive analysis) to assess their stability throughout murine preimplantation embryo development from the oocyte to the late blastocyst stages, both in whole embryos and the associated conditioned culture media. In descending order of effectiveness, miR-16, miR-191 and miR-106 were identified as the most stable individual reference miRNAs for developing whole CD1 murine preimplantation embryos, while miR-16, miR-106 and miR-103 were ideal for the conditioned culture media. Notably, the widely used U6 reference was among the least appropriate for normalizing both whole embryo and conditioned media miRNA datasets. Incorporating multiple reference miRNAs into the normalization basis via a geometric mean was deemed beneficial, and combinations of each set of stable miRNAs are further recommended, pending validation on a per experiment basis.
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Rodriguez-Purata, Jorge, and Francisca Martinez. "Ovarian stimulation for preimplantation genetic testing." Reproduction 157, no. 4 (April 2019): R127—R142. http://dx.doi.org/10.1530/rep-18-0475.
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A narrative review of the management of controlled ovarian stimulation in patients undergoing preimplantation genetic testing is presented. An electronic search was performed to identify research publications that addressed ovarian stimulation and preimplantation genetic testing published until December 2017. Studies were classified in decreasing categories: randomized controlled trials, prospective controlled trials, prospective non-controlled trials, retrospective studies and experimental studies. The aim of controlled ovarian stimulation has shifted from obtaining embryos available for transfer to yielding the maximum embryos available for biopsy to increase the odds of achieving one euploid embryo available for transfer, without the distress of inducing ovarian hyperstimulation syndrome or inadequate endometrium receptivity as vitrification and deferred embryo transfer usually will be planned. The present narrative review summarizes all treatment-related variables as well as stimulation strategies after controlled ovarian stimulation that could help patients undergoing an in vitro fertilization cycle coupled with preimplantation genetic testing, including the number of oocytes needed to achieve one healthy live birth, oral contraceptive pill usage, the role of mild ovarian stimulation or random-start stimulation, the stimulation protocol and type of gonadotropin of choice, the novel progesterone protocols, agonist or dual trigger as a final oocyte maturation trigger, the accumulation of oocytes/embryos and the optimal interval before proceeding with a subsequent controlled ovarian stimulation or the optimal medication to link stimulation cycles. The discussion is being presented according to how questions are posed in clinical practice. The aim of ovarian stimulation has shifted from obtaining embryos available for transfer to yielding the maximum embryos available for biopsy to increase the odds of achieving one euploid embryo available for transfer.
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Jin, X., V. Chandrakanthan, and C. O.'Neill. "427. MDM2 maintains the latency of expression of TRP53 in the mouse preimplantation embryo." Reproduction, Fertility and Development 20, no. 9 (2008): 107. http://dx.doi.org/10.1071/srb08abs427.
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TRP53 is a tumour suppressor that causes cell-cycle arrest or cell death in response to a range of stressors. Normal preimplantation embryo development requires that TRP53 is maintained in a labile state1. Culture of mouse C57BL6 preimplantation embryos causes this latency to be breached and this is a cause of the low embryo viability following culture. MDM2 is an ubiquitin ligase that targets TRP53 for degradation by the proteosome. MDM2 is activated by Serine 166 phosphorylation (pMDM2). This is commonly catalysed by the phosphatidylinositol-3 kinase (PI3K) and AKT signalling pathway. A range of embryotrophins activate the PI3K and AKT pathway. This study tested the hypothesis that TRP53 is maintained in a latent state in the normal embryo by the activation of MDM2 by the actions of embryotrophins via a PI3K and AKT signalling pathway. Genetic deletion of Mdm2 prevents normal preimplantation development in a Trp53 dependent manner2. Addition of an MDM2 inhibitor (Nutlin-3) to culture medium caused a dose-dependent inhibition of zygote development (P < 0.001) that did not occur in Trp53−/−embryos. Immunofluorescence and western blot analysis detected pMDM2 throughout mouse preimplantation development. Zygote culture reduced the levels of pMDM2 formation. Furthermore, blocking the actions of Paf, PI3K or AKT in vitro reduced in the expression of pMDM2, and also resulted in higher levels of TRP53 expression in embryos. The embryopathy resulting from increased TRP53 could be partially ameliorated by the addition of the TRP53 antagonist α-pifithrin to media (P < 0.05). The results show MDM2 was activated by an embryotrophin (Paf), PI3K and AKT signalling pathway and was required for the latency of TRP53 expression in the preimplantation embryos. (1) Li A, Chandrakanthan V, Chami O, O’Neill C. (2007) Biology of Reproduction 76: 362–367. (2) Montes de Oca Luna R, Wagner DS, Lozano G. (1995) Nature 378: 203–205.
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Wale, P. L., and D. K. Gardner. "174. ATMOSPHERIC OXYGEN ALTERS THE EMBRYONIC METABOLOME AS QUANTIFIED BY CARBOHYDRATE UPTAKE AND AMINO ACID UTILISATION." Reproduction, Fertility and Development 22, no. 9 (2010): 92. http://dx.doi.org/10.1071/srb10abs174.
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Oxygen regulates embryo development at both the cleavage and post compaction stages. In this study we investigated the effects of atmospheric oxygen during the preimplantation stages, on the post-compaction embryonic metabolome through quantification of glucose consumption and amino acid utilization. Zygotes obtained from F1 hybrid mice (C57BLxCBA) were randomly allocated to either 5 or 20% oxygen. In the first experiment, following the first 48 h of culture, embryos were cultured individually in 1 μL drops of modified G2 medium (0.5 mM glucose) and moved to fresh drops of medium every 24 h. The glucose concentration in the spent media samples, including controls containing no embryo, was determined by microfluorimetry. In the second experiment, embryos which had developed to the early blastocyst stage after 72 h were cultured for a further 24 h in groups of 10 in 2 μL drops of G2. Analysis of amino acid utilization was performed using liquid chromatography-triple quadrupole mass spectrometry. Glucose consumption by embryos cultured in 5% oxygen was significantly greater on day 4 and day 5 (4.89 ± 0.29 and 6.13 ± 0.41 pmol/embryo/h) compared to embryos cultured in 20% oxygen (2.59 ± 0.40 and 5.09 ± 0.28 pmol/embryo/h; P < 0.05). In contrast amino acid utilisation by embryos cultured in 5% oxygen was significantly less than embryos cultured in 20% oxygen (P < 0.05). The data generated will help to determine the aetiology of oxygen toxicity to the preimplantation embryo. Higher glucose utilisation by embryos in 5% oxygen is consistent with their improved development. Conversely, the increased utilisation of amino acids by blastocysts in 20% oxygen may reflect an adaptation to increased oxidative stress as a result of culture in a non-physiological oxygen concentration. This study demonstrates that atmospheric oxygen during the preimplantation period perturbs the embryonic metabolome which results in a compensatory increase in amino acid utilisation.
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Garcia-Dominguez, Ximo, Gianfranco Diretto, Sarah Frusciante, José Salvador Vicente, and Francisco Marco-Jiménez. "Metabolomic Analysis Reveals Changes in Preimplantation Embryos Following Fresh or Vitrified Transfer." International Journal of Molecular Sciences 21, no. 19 (September 26, 2020): 7116. http://dx.doi.org/10.3390/ijms21197116.
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Although assisted reproduction technologies (ARTs) are recognised as safe, and most of the offspring seem apparently healthy, there is clear evidence that ARTs are associated with changes in the embryo’s developmental trajectory, which incur physiological consequences during the prenatal and postnatal stages of life. The present study aimed to address the influence of early (day-3 embryos) embryo transfer and cryopreservation on embryo survival, size, and metabolome at the preimplantation stage (day-6 embryos). To this end, fresh-transferred (FT) and vitrified-transferred (VT) embryos were compared using naturally-conceived (NC) embryos as a control reference. The results show that as in vitro manipulation was increased (NC < FT < VT), both embryo survival rate (0.91 ± 0.02, 0.78 ± 0.05 and 0.63 ± 0.05, for NC, FT, and VT groups, respectively) and embryo size (3.21 ± 0.49 mm, 2.15 ± 0.51 mm, 1.76 ± 0.46 mm of diameter for NC, FT, and VT groups, respectively) were significantly decreased. Moreover, an unbiased metabolomics analysis showed overall down-accumulation in 40 metabolites among the three experimental groups, with embryo transfer and embryo cryopreservation procedures both exerting a cumulative effect. In this regard, targeted metabolomics findings revealed a significant reduction in some metabolites involved in metabolic pathways, such as the Krebs cycle, amino acids, unsaturated fatty acids, and arachidonic acid metabolisms. Altogether, these findings highlight a synergistic effect between the embryo transfer and vitrification procedures in preimplantation embryos. However, the ex vivo manipulation during embryo transfer seemed to be the major trigger of the embryonic changes, as the deviations added by the vitrification process were relatively smaller.
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Chu, Da-Peng, Shi Tian, Da-Guang Sun, Chan-Juan Hao, Hong-Fei Xia, and Xu Ma. "Corrigendum to: Exposure to mono-n-butyl phthalate disrupts the development of preimplantation embryos." Reproduction, Fertility and Development 26, no. 3 (2014): 491. http://dx.doi.org/10.1071/rd12178_co.
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Dibutyl phthalate (DBP), a widely used phthalate, is known to cause many serious diseases, especially in the reproductive system. However, little is known about the effects of its metabolite, mono-n-butyl phthalate (MBP), on preimplantation embryo development. In the present study, we found that treatment of embryos with 10–3M MBP impaired developmental competency, whereas exposure to 10–4M MBP delayed the progression of preimplantation embryos to the blastocyst stage. Furthermore, reactive oxygen species (ROS) levels in embryos were significantly increased following treatment with 10–3M MBP. In addition, 10–3M MBP increased apoptosis via the release of cytochrome c, whereas immunofluorescent analysis revealed that exposure of preimplantation embryos to MBP concentration-dependently (10–5, 10–4 and 10–3M) decreased DNA methylation. Together, the results indicate a possible relationship between MBP exposure and developmental failure in preimplantation embryos.