Assessment of fetal behavior
Hung N. Winn, Frank A. Chervenak, Roberto Romero in Clinical Maternal-Fetal Medicine Online, 2021
The early embryonic development is characterized by the immobility of an embryo. Most types of movement pattern emerge between 7 and 15 weeks of gestation. From the 15th week onward, distinct patterns can be seen (6). These movements remain present during the entire intrauterine development. Just discernible movements were found between 7 and 8 weeks of gestation by de Vries and coworkers (7). They reported not only how to describe a particular movement, but also how these movements were performed in terms of speed and amplitude (7,8). Goldstein and colleagues as well as other investigators found embryonic body movements between 8 and 9 weeks of gestation by 2D transvaginal sonography (7,9–11). First spontaneous fetal movements were described as consisted of slow flexion and extension of fetal trunk accompanied by the displacement of arms and legs and appearing in irregular sequences that were described as “vermicular” (12). The earliest signs of fetal motility coincide with the occurrence of first synapses, around the seventh postconceptional week and with the earliest electrical activity and transmission of information.
Stem cell biology
Christine Hauskeller, Arne Manzeschke, Anja Pichl in The Matrix of Stem Cell Research, 2019
These considerations about stem cell potency suggest further assumptions relevant to developmental process D, which orders cell states on a continuum of differentiation. The simplest way to conceive a developmental process, at the cell level, is as a linear sequence of cell states ordered in time. This is how whole-organism stages of embryonic development were represented, in the early days of the science (Hopwood, 2005). But cell developmental processes are coordinated with cell division events, such that stages are often arranged in a branching hierarchy rather than a single linear sequence. So variable D can, like variable L, be further analysed as a set of sub-variables, which together delimit the range of possible topologies for cell lineage trees: d, number of stages (depth of developmental hierarchy)p, number of termini (a cell’s developmental potential)a, arrangement of branch-points (the number of which = p–1)
The Male Factor in Recurrent Pregnancy Loss
Howard J.A. Carp in Recurrent Pregnancy Loss, 2020
Examination on a molecular level seems to agree with these clinical conclusions. Sperm chromatin is notable for its three-part structure. Most sperm chromatin is condensed within toroid coils bound to protamines [8–11], with other regions bound by histones [15] and intervals with nuclear matrix attachment [13,14]. While the sperm protamine is replaced by histones shortly after fertilization, some research has suggested that the histone-bound and matrix-associated regions are passed to the embryonic DNA and are important for development [15–17]. For example, one study found that embryos fertilized by sperm with disrupted matrices cannot divide past the one-cell stage [18]; another study showed that retained nucleosomes were significantly enriched with epigenetic modifications at loci important in developmental regulation [19]. Protamines themselves are crucial for fertility, and the ratio of sperm protamine RNA has been used to counsel patients regarding chances of success with assisted reproductive technology (ART) [20,21]. Rogenhofer et al. evaluated protamine mRNA content from sperm of 25 men with unexplained RPL compared to 32 healthy volunteers (with normal semen parameters, but not confirmed fertility). Elevated levels of both protamine 1 and 2 mRNA were found in men with RPL, suggesting that tight regulation of protamine levels may be responsible for appropriate initiation of paternal gene expression. Thus, while the specific roles of the sperm genome in embryonic development
Current status of sperm functional genomics and its diagnostic potential of fertility in bovine (Bos taurus)
Published in Systems Biology in Reproductive Medicine, 2018
Sellappan Selvaraju, Sivashanmugam Parthipan, Lakshminarayana Somashekar, B. Krishnan Binsila, Atul P. Kolte, Arunachalam Arangasamy, Janivara Parameshwaraiah Ravindra, Stephen A. Krawetz
During fertilization, the spermatozoon delivers transcripts that may have a function during embryonic development. For instance, PRM1 transcripts are abundant in bovine spermatozoa (Hecht et al. 2011) and are delivered by the spermatozoon to the oocyte. The differential expression of mRNAs in testis (214 up and 226 down-regulated) and sperm (272 increased and 111 decreased), between different fertile animals suggests that differential mRNA levels could be used to assess sub fertility in mammals. Mouse sperm treated with RNase H and RNase A presented delayed blastocyst formation and reduced live birth rate (Gao et al. 2017) and lends further support that sperm carry RNAs essential for embryo development (Ostermeier et al. 2004; Krawetz 2005). Levels of CASP3, UBE2D3, TRADD, and HSFY2 in spermatozoa show a significant negative correlation with the field conception rate in bovine. These apoptotic factors might be useful as a means to assess the fertility of the bull semen (Parthipan et al. 2017)
Risk of embryo aneuploidy is affected by the increase in sperm DNA damage in recurrent implantation failure patients under ICSI-CGH array cycles
Published in Human Fertility, 2022
Fatemeh Asgari, Azam Gavahi, Mehrdad Karimi, Akram Vatannejad, Fatemehsadat Amjadi, Reza Aflatoonian, Zahra Zandieh
Sperm provides half of the embryo’s genome, and therefore significantly contributing to normal fertilisation, embryonic development, and successful implantation (Agarwal et al., 2009; Simon et al., 2016; Tsuribe et al., 2016). During the ICSI procedure, injected sperm are routinely selected in terms of the morphological and motility criteria, regardless of their DNA integrity (Tarozzi et al., 2019). Nevertheless, in some cases, even morphologically normal embryos failed to implant or lead to an unsuccessful pregnancy (Magli et al., 1998). Moreover, studies have shown that about 60% of infertile men have damaged sperm DNA (Gharagozloo et al., 2016; Simon et al., 2016), and high sperm DNA fragmentation has been associated with the reduced fertilisation rate and poor embryo quality (Seli et al., 2004; Virro et al., 2004; Zini et al., 2008). DNA damage can be considered as the result of the disruption in chromatin condensation, small deletions, chromosome rearrangement, apoptosis or oxidative stress (Tsuribe et al., 2016).
Fertilisation and early embryonic development of immature and rescue in vitro-matured sibling oocytes
Published in Human Fertility, 2022
Berrin Avci, Isil Kasapoglu, Cihan Cakir, Aysun Ozbay, Baris Ata, Gurkan Uncu
The rates of cleavage in the early embryonic development of the study groups were 31.7%, 19.9%, 21.6%, 53.8% per oocyte (no. of cleavage embryos on day 2/all oocytes injected) and 61.1%, 51.1%, 71.6%, 90.5% per zygote (no. of cleavage embryos on day 2/all zygotes) in Groups 1, 2, 3 and 4, respectively (both at p < 0.001). As expected, the highest cleavage rate was detected in Group 4 (53.8% and 90.5%). When the cleavage rate was evaluated per injected oocyte, statistical significance in terms of cleavage rate was observed between Group 1 and Group 2 (p = 0.02), Group 1–Group 3 (p = 0.05), Group 1–Group 4 (p < 0.001), Group 2–Group 4 (p < 0.001) and Group 3–Group 4 (p < 0.001). Statistical significance was not observed between Group 2 and Group 3 (p = 0.54). However, when the cleavage rate was evaluated per zygote, significant differences were observed between all groups (p < 0.005 for all) except for Group 1–Group 2 and Group 1–Group 3 (p = 0.3 and p = 0.2, respectively) (Table 2 and Figure 2).