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Embryo Cell-Free DNA in the Culture Medium and Its Potential for Non-Invasive Aneuploidy Testing
Published in Carlos Simón, Carmen Rubio, Handbook of Genetic Diagnostic Technologies in Reproductive Medicine, 2022
Carmen Rubio, Luis Navarro-Sánchez, Carmen M. García-Pascual
Researchers and clinicians agree that avoiding embryo biopsy for genetic evaluation would be economically and practically advantageous and would reduce the risk of embryo damage. Reported concordance rates between embryo cfDNA and blastocyst biopsy vary widely, and most sample sizes are relatively low. However, our analysis of 1,301 samples from eight different laboratories establishes the clinical potential of this non-invasive approach [17]. Furthermore, our comparison of embryo cfDNA with ICM biopsies (representing the embryo itself) in a subset of blastocysts showed concordance rates similar to those between cfDNA and TE biopsies. These findings pave the way for the clinical application of a non-invasive approach that would avoid embryo manipulation and decrease the methodological complexity and cost of analysis, thus allowing every IVF laboratory to offer embryo aneuploidy testing to all IVF patients. While contamination by maternal cumulus cells may contribute to false-negative results, this risk can be mitigated through careful removal of cumulus cells following oocyte pickup and through serial washing of the oocytes and embryos to eliminate all traces of maternal DNA.
Capacitation, the Acrosome Reaction, and Motility in Mammalian Sperm
Published in Claude Gagnon, Controls of Sperm Motility, 2020
Susan S. Suarez, John W. Pollard
The cumulus is comprised of cumulus cells derived from the follicular cells surrounding the developing oocyte and various macromolecular and ionic components secreted by the cumulus cells or derived from follicular fluid. Since the discovery of the acrosome reaction more than 30 years ago, investigators have searched among these components for a specific inducer of the reaction. Interpretation of results obtained from incubating spermatozoa with putative inducing factors from the cumulus have been fraught with problems, most of which stem from separating the effect of factors on capacitation from their effect on the acrosome reaction. Apparently, acrosome reactions can occur spontaneously in some capacitated sperm; therefore, a factor that appears to induce the acrosome reaction may only be hastening the process of capacitation. This would be the case if the factor only increases the percentage of acrosome-reacted sperm when it has been incubated with sperm for long periods (hours instead of minutes). On the other hand, if a factor does not induce acrosome reactions, it may be that the sperm were not capacitated sufficiently to expose receptors for the factor.
Regulation of Reproduction by Dopamine
Published in Nira Ben-Jonathan, Dopamine, 2020
A fully grown oocyte is tightly surrounded by compact layers of specialized granulosa cells (cumulus cells), forming a cumulus–oocyte complex. The process of meiosis resumption requires integration of endocrine, paracrine and autocrine signaling pathways involving interactions between the oocyte and the surrounding granulosa and cumulus cells. Ovulation occurs only once the first meiotic division has completed and a secondary oocyte has been formed within the dominant follicle. As discussed in Section 10.6, the completion of oogenesis (stage 5) occurs at the time of fertilization, when the secondary oocyte completes meiosis II and produces a very large, mature haploid ovum that unites with the sperm. The different stages of oogenesis and folliculogenesis are presented in Table 10.3 and illustrated in Figure 10.11.
The effects of prenatal and lactational bisphenol A and/or di(2-ethylhexyl) phthalate exposure on female reproductive system
Published in Toxicology Mechanisms and Methods, 2022
Gizem Ozkemahli, Aylin Balci Ozyurt, Pinar Erkekoglu, Naciye Dilara Zeybek, Nilgun Yersal, Belma Kocer-Gumusel
The follicles belonging to all stages of follicular development and corpus luteum were observed both in the control and experimental groups. The primordial follicles in which the oocytes were surrounded by a single layer of squamous epithelial cells and primary follicles in which oocytes surrounded by cuboidal epithelial cells were present in all groups. The secondary follicles with more than one layer of granulosa cells and tertiary follicles with antral formation were also observed in the sections. Atretic follicles in which pyknotic and/or disorganized granulosa cells and a degenerating oocyte surrounded by an envelope of degenerating cumulus cells were present. Loss of cumulus cells was observed in some of the atretic follicles. Follicular cysts were observed in the BPA + DEHP group.
The Kisspeptin and Kisspeptin receptor in follicular microenvironment: is that really necessary for oocyte maturation and fertilisation?
Published in Journal of Obstetrics and Gynaecology, 2022
Goktan Kuspinar, Cihan Cakır, Isıl Kasapoglu, Seda Saribal, Barbaros Oral, Ferah Budak, Gurkan Uncu, Berrin Avcı
Kisspeptin injection could trigger both oocyte maturation and ovulation in female rats and humans (Abbara et al. 2014; Roa et al. 2006). Given that kisspeptin can cross the blood–brain barrier and then stimulate LH to release the peripheral circulation, we can expect a dramatically elevated LH level in plasma following the kisspeptin injection (Abbara et al. 2014; Roa et al. 2006). Therefore, it is difficult to establish a theoretical concept that kisspeptin can directly induce oocyte maturation in the ovary because the elevated LH level can also influence oocyte maturation. Nevertheless, kisspeptin has been shown to enhance the in vitro maturation of the pig’s oocytes (Saadeldin et al. 2012). However, that study used an in vitro culture system of the cumulus– oocyte complex instead of the denuded oocytes. Since both cumulus cells and oocyte can express KISS1R in pigs (Saadeldin et al. 2012), it is easily confused whether the kisspeptin induced oocyte maturation is mediated by the cumulus cells or the oocyte itself. In this study, the oocytes obtained from the controlled ovarian stimulation cycle and the oocyte's cumulus cells were evaluated without in vivo culture. KISS1 and KISS1R gene expression levels in cumulus cells were not found correlated with oocyte maturation stage and fertilisation status.
Application of ultrasound markers measured at different time points of COH cycle in the prediction of ovarian response for individualised ovulation induction
Published in Journal of Obstetrics and Gynaecology, 2022
Yue-Wei Li, Xiao-Wen Liang, Jing-Hui Fang, Zhi-Yi Chen
The growth of cumulus cells is closely related to the development of the oocyte, and cumulus cell apoptosis affects the maturation, fertilisation, and cleavage of the oocyte and may thus be used to predict IVF outcomes. With the advancement of high-resolution TV-CDS, ultrasound features can be regarded as markers in the evaluation of ovarian response. Moreover, TV-CDS is more likely to detect the cumulus on the day of hCG injection, thus indirectly indicating a good ovarian response, which is correlated with the number of retrieved oocytes, fertilised eggs, and excellent-grade embryos (Jadaon et al. 2012). In this study, we found that the number of cumulus oophorus observed on the day of hCG injection was positively correlated with the number of oocytes and fertilised oocytes. The number of cumulus oophorus gradually increased from the low response group to the normal response group and the high response group, and the number of oocytes retrieved, the number of fertilised oocytes, and the number of high-quality embryos also gradually increased. These results indirectly prove that the cumulus oophorus is a syncytium with complete structure and function, which is closely related to the growth, development, maturation, and fertilisation of oocytes (Tola et al. 2019). According to Bertolin's study, successful fertilisation is related to the quantity and quality of cumulus expansion. The cumulus oophorus creates a beneficial microenvironment for the growth and development of oocytes (Bertolin et al. 2017). The cumulus oophorus is essential for normal oocyte development, ovulation, and fertilisation.