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Intracytoplasmic Sperm Injection
Published in Botros Rizk, Ashok Agarwal, Edmund S. Sabanegh, Male Infertility in Reproductive Medicine, 2019
Emad Fakhry, Medhat Amer, Botros Rizk
Oocyte activation: After ICSI, several sperm factors can cause calcium oscillations in the oocyte cytoplasm and subsequent oocyte activation. When there is a specific indication, such as previous fertilization failure or globozoospermia, then artificial oocyte activation (AOA) is beneficial [37]. AOA procedures are commonly divided into three categories: mechanical by vigorous cytoplasmic aspiration during sperm injection, electrical, and chemical stimulation by calcium ionophore or ionomycin. There are no studies in humans to define the best method, although in pigs, the chemical stimulation was better than the electrical one in terms of blastulation [38]. In addition to fertilization failure, developmental incompetence of embryos is suggested to be an additional indication for ionophore treatment, but this suggestion needs further confirmation [39].
Assisted oocyte activation Current understanding, practice, and future perspectives
Published in David K. Gardner, Ariel Weissman, Colin M. Howles, Zeev Shoham, Textbook of Assisted Reproductive Techniques, 2017
IVF involves a series of concurrent events required to ensure that the mature sperm and oocyte are able to suc- cessfully combine to produce a new individual. For com- petent fertilization to occur, it is essential to alleviate meiotic arrest (at the second metaphase of meiosis [MII]) of the unfertilized oocyte. The most obvious indications of such meiotic resumption are second polar body extru- sion and formation of the male and female pronuclei (1). Fertilization also involves cortical granule exocytosis and the initiation of the first cell cycle (1–5). These early biochemical and morphological events in the oocyte are collectively termed “oocyte activation.” It is important to appreciate that oocyte activation is a distinct and separable part of the fertilization process, in that oocyte activation can occur without sperm entry, and that sperm entry can occur without oocyte activation. It is this second scenario, where a sperm is clearly within the oocyte without the occurrence of activation events, which suggests one can induce activation via artificial means. Such methods have generally been based upon our fluctuating understanding of how the sperm causes physiological oocyte activation at fertilization.
Artificial oocyte activation: physiological, pathophysiological and ethical aspects
Published in Systems Biology in Reproductive Medicine, 2019
George Anifandis, Alexandros Michopoulos, Alexandros Daponte, Katerina Chatzimeletiou, Mara Simopoulou, Christina I. Messini, Nikolas P. Polyzos, Katerina Vassiou, Konstantinos Dafopoulos, Dimitrios G. Goulis
Much controversy exists regarding the ‘receptor-based’ and the ‘sperm-factor’ theory. Although the first theory was intriguing, the second theory gained much attention and was widely accepted since the characteristics that possess the soluble factor induce Ca+2 oscillations through the PLC pathway (Dale et al. 1985, 2010). Moreover, the ‘receptor-based’ mechanism was soon abandoned since Ca+2 imaging technology failed to highlight a sperm-ligand that binds to oocyte receptors and initiates Ca+2 oscillations (Amdani et al. 2015). Therefore, oocyte activation is induced by a spermatozoon-derived factor, which is released into the ooplasm during fertilization. This hypothesis was further supported by the finding that injection of an extract isolated by the head of the spermatozoon induces repetitive Ca+2 oscillations (Swann 1990; Machaty et al. 2000). Moreover, the fact that oocytes can be activated during the ICSI procedure supports the above hypothesis (Parrington et al. 1996, 2007; Parrington 2001).
Systems Biology in Reproductive Medicine 2019
Published in Systems Biology in Reproductive Medicine, 2019
The first issue of our 11th year includes papers that once again emphasize the scope of the journal. This issue begins with a Review Article from our new Board Member Dr. George Anifandis and colleagues titled ‘Artificial oocyte activation: physiological, pathophysiological and ethical aspects’, providing a current state of the art summation. The remaining related papers cover the assessment of risk of a birth defect by Dr. Jing Zhu et al.; examining the levels of interleukin during in vitro fertilization by Dr. Laurice Bou Nemer et al.; cryopreservation by Dr. Munevver Serdarogullari et al.; growth hormone deficiency by Drs. Dragoş Albu and Alice Albu; a quartet of papers from Drs. Oya S. Aydos et al., Grigory A. Demyashkin, Ying Ma et al., and Linjun Chen et al. discussing mechanisms of infertility, sperm diagnostics, and their impact on outcome; papers from Dr. Abdullah Karaer et al. that examines the metabolic analysis of follicular fluid and Dr. Soraya Labied et al. on embryo culture; and closing this issue, the work of Dr. Eduardo H. Umeoka et al. who examine reproductive performance and fetal development.
Artificial oocyte activation with calcium ionophore for frozen sperm cycles
Published in Systems Biology in Reproductive Medicine, 2018
Seda Karabulut, Özlem Aksünger, Can Ata, Yusuf Sağıroglu, İlknur Keskin
Artificial oocyte activation (AOA) is the most common treatment strategy used for fertilization problems (Ebner et al. 2012) to achieve successful fertilization, especially in problems of total fertilization failure (TFF) and in decreased fertilization rates. TFF cases are observed in routine practice of ARTs with an incidence of ~1–3% of ICSI cycles and may be reobserved in subsequent cycles (Flaherty et al. 1998; Esfandiari et al. 2005; Kashir et al. 2010). Sperm-related problems that may result in TFF are non-viability, altered chromatin status, inability to activate the oocyte, and decondensation failure (Nasr Esfahani et al. 2010). The main oocyte-related factor that leads to TFF is failed activation. Oocyte activation process is a result of complex interactions triggered by the entrance of the sperm cell into the oocyte. Intracellular Ca2+ rise observed shortly after spermatozoon–oocyte fusion is the initiator mechanism of oocyte activation (Miyazaki and Ito 2006; Ramadan et al. 2012).