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Rescue of failed oocyte activation after ICSI in a mouse model of male factor infertility by recombinant phospholipase C?.

ABSTRACT: Artificial oocyte activation to overcome failed fertilization after intracytoplasmic sperm injection (ICSI) in human oocytes typically employs Ca(2+) ionophores to produce a single cytosolic Ca(2+) increase. In contrast, recombinant phospholipase Czeta (PLC?) causes Ca(2+) oscillations indistinguishable from those occurring during fertilization, but remains untested for its efficacy in a scenario of ICSI fertilization failure. Here, we compare PLC? with other activation stimuli in a mouse model of failed oocyte activation after ICSI, in which heat-treated sperm are injected into mouse oocytes. We show that increasing periods of 56 °C exposure of sperm produces a progressive loss of Ca(2+) oscillations after ICSI. The decrease in Ca(2+) oscillations produces a reduction in oocyte activation and embryo development to the blastocyst stage. We treated such oocytes that failed to activate after ICSI either with Ca(2+) ionophore, or with Sr(2+) media which causes Ca(2+) oscillations, or we injected them with recombinant human PLC?. All these treatments rescued oocyte activation, although Sr(2+) and PLC? gave the highest rates of development to blastocyst. When recombinant PLC? was given to oocytes previously injected with control sperm, they developed normally to the blastocyst stage at rates similar to that after control ICSI. The data suggest that recombinant human PLC? protein is an efficient means of rescuing oocyte activation after ICSI failure and that it can be effectively used even if the sperm already contains endogenous Ca(2+) releasing activity.

SUBMITTER: Sanusi R

PROVIDER: S-EPMC4586348 | biostudies-literature | 2015 Oct

REPOSITORIES: biostudies-literature

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Rescue of failed oocyte activation after ICSI in a mouse model of male factor infertility by recombinant phospholipase Cζ.

Sanusi Randa R Yu Yuansong Y Nomikos Michail M Lai F Anthony FA Swann Karl K

Molecular human reproduction 20150717 10

Artificial oocyte activation to overcome failed fertilization after intracytoplasmic sperm injection (ICSI) in human oocytes typically employs Ca(2+) ionophores to produce a single cytosolic Ca(2+) increase. In contrast, recombinant phospholipase Czeta (PLCζ) causes Ca(2+) oscillations indistinguishable from those occurring during fertilization, but remains untested for its efficacy in a scenario of ICSI fertilization failure. Here, we compare PLCζ with other activation stimuli in a mouse model ...[more]

PMID: 26187950

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Project description:IntroductionAttempts to artificially activate unfertilized oocytes at 24 h post intracytoplasmic sperm injection (ICSI) have generally resulted in poor outcomes. This study aims to explore a new strategy for early judgement and rescue activation of unfertilized oocytes at 5 h post ICSI to avoid unexpected fertilization failure (UFF) or unexpected low fertilization (ULF) in ICSI cycles.MethodsFirstly, time-lapse data from 278 ICSI cycles were retrospectively analyzed to establish an indicator for fertilization failure prediction. Secondly, 14 UFF and 20 ULF cycles were enrolled for an observational study, early rescue oocyte activation (EROA) was performed on oocytes without post-ICSI Pb2 extrusion to investigate fertilization efficiency, embryo development and clinical outcomes.ResultsThe average time to Pb2 extrusion post-ICSI was 3.03±1.21 h, 95.54% of oocytes had extruded Pb2 before 5 h, and the sensitivity and specificity for monitoring Pb2 extrusion at 5 h by time-lapse imaging to predict fertilization were 99.59% and 99.78%, respectively. Early rescue activation of oocytes with no Pb2 extrusion resulted in acceptable fertilization and embryo developmental outcomes, in terms of the fertilization rate (75.00, 72.99%), 2PN fertilization rate (61.36, 56.93%), good-quality embryo rate (42.59, 50.00%), blastocyst formation rate (48.28, 46.03%), good-quality blastocyst rate (34.48, 33.33%), and oocyte utilization rate (36.36, 27.74%), for both UFF and ULF cycles. The clinical pregnancy, embryo implantation, and early miscarriage rates in the rescue oocyte activation group did not significantly differ from those in the Pb2 extrusion group. Fourteen unexpected fertilization failures and 20 low fertilization ICSI cycles were rescued and resulted in clinical pregnancy rates of 40.00% (4/10) and 57.14% (8/14), respectively.ConclusionsThis study demonstrates that monitoring Pb2 extrusion by time-lapse imaging can accurately predict fertilization outcomes, suggesting that early rescue oocyte activation at 5 h post ICSI is an effective strategy for avoiding unexpected fertilization failure and low fertilization in ICSI cycles.

Project description:We recently identified the DPY19L2 gene as the main genetic cause of human globozoospermia (70%) and described that Dpy19l2 knockout (KO) mice faithfully reproduce the human phenotype of globozoospermia making it an excellent model to characterize the molecular physiopathology of globozoospermia. Recent case studies on non-genetically characterized men with globozoospermia showed that phospholipase C, zeta (PLCζ), the sperm factor thought to induce the Ca(2+) oscillations at fertilization, was absent from their sperm, explaining the poor fertilization potential of these spermatozoa. Since 30% of globozoospermic men remain genetically uncharacterized, the absence of PLCζ in DPY19L2 globozoospermic men remains to be formally established. Moreover, the precise localization of PLCζ and the reasons underlying its loss during spermatogenesis in globozoospermic patients are still not understood. Herein, we show that PLCζ is absent, or its presence highly reduced, in human and mouse sperm with DPY19L2-associated globozoospermia. As a consequence, fertilization with sperm from Dpy19l2 KO mice failed to initiate Ca(2+) oscillations and injected oocytes remained arrested at the metaphase II stage, although a few human oocytes injected with DPY19L2-defective sperm showed formation of 2-pronuclei embryos. We report for the first time the subcellular localization of PLCζ in control human sperm, which is along the inner acrosomal membrane and in the perinuclear theca, in the area corresponding to the equatorial region. Because these cellular components are absent in globozoospermic sperm, the loss of PLCζ in globozoospermic sperm is thus consistent and reinforces the role of PLCζ as an oocyte activation factor necessary for oocyte activation. In our companion article, we showed that chromatin compaction during spermiogenesis in Dpy19l2 KO mouse is defective and leads to sperm DNA damage. Together, these defects explain the poor fertilization potential of DPY19L2-globozoospermic sperm and the compromised developmental potential of embryos obtained using sperm from patients with a deletion of the DPY19L2 gene.

Project description:PurposeWe performed a systematic review and meta-analysis of available literature to investigate the efficacy of the intracytoplasmic sperm injection (ICSI) in couples with non-male factor with respect to the clinical outcomes.MethodsThe literature search was based on EMBASE, PubMed, and the Cochrane Library. All studies published after 1992 until February 2020 and written in English addressing patients in the presence of normal semen parameters subjected to ICSI and in vitro fertilization (IVF) were eligible. Reference lists of retrieved articles were hand-searched for additional studies. The primary outcomes were fertilization rate, clinical pregnancy rate, and implantation rate; the secondary outcomes were good-quality embryo rate, miscarriage rate, and live birth rate.ResultsFour RCTs and twenty-two cohort studies fulfilling the inclusion criteria were included. Collectively, a meta-analysis of the outcomes in RCTs showed that compared to IVF, ICSI has no obvious advantage in fertilization rate (RR = 1.16, 95% CI: 0.83-1.62), clinical pregnancy rate (RR = 1.04, 95% CI: 0.66-1.64), implantation rate (RR = 1.12, 95% CI: 0.67-1.86), and live birth rate (RR = 1.17, 95% CI: 0.43-3.15). Pooled results of cohort studies demonstrated a statistically significant higher fertilization rate (RR = 1.16, 95% CI: 1.03-1.31) and miscarriage rate (RR = 1.04, 95% CI: 1.01-1.06) in the ICSI group; furthermore, higher clinical pregnancy rate (RR = 0.85, 95% CI: 0.77-0.94), implantation rate (RR = 0.78, 95% CI: 0.65-0.95), and live birth rate (RR = 0.86, 95% CI: 0.79-0.94) was founded in the IVF group; no statistically significant difference was observed in good-quality embryo rate (RR = 0.98, 95% CI: 0.93-1.04).ConclusionICSI has no obvious advantage in patients with normal semen parameters. Enough information is still not available to prove the efficacy of ICSI in couples with non-male factor infertility comparing to IVF.

Project description:INTRODUCTION:Intracytoplasmic sperm injection (ICSI), originally introduced as add-on to in vitro fertilisation (IVF) for couples with severe male infertility, is in current clinical practice also used in couples with mild male or even unexplained infertility. However, ICSI has involved unresolved concerns regarding the selection and damage to gametes and the health conditions of the offspring, and it is also labour intensive and therefore more expensive than conventional IVF. High-quality well-powered randomised clinical trials (RCTs) comparing ICSI and IVF are lacking. METHODS AND ANALYSIS:We propose a multicentre, open-label RCT in 10 reproductive medical centres across China. We will study couples with non-severe male infertility (defined as a semen concentrate 5-15×106/mL or sperm with a progressive motility 10%-32%) scheduled for their first or second ICSI or IVF cycle, as low fertility rate after fertilisation are more frequent in this population, which could lead to controversy about ICSI or conventional IVF for fertilisation. On the day of oocyte retrieval, eligible participants are after informed consent be randomised to undergo either ICSI or conventional IVF in a 1:1 treatment ratio. Other standard assisted reproductive treatments are similar and parallel between two groups. Our primary outcome is ongoing pregnancy leading to live birth after the first cycle with embryo transfer. To demonstrate or refute a difference of 7% between ICSI and conventional IVF, we need to include 2346 women (1173 in each intervention arm). In addition, we will follow-up neonatal outcomes after delivery to identify the influence of ICSI on offspring. ETHICS AND DISSEMINATION:Ethical approval was obtained from Peking University Third Hospital medical science research ethics committee. The findings will be disseminated to the public through conference presentations and peer-reviewed scientific journals. TRIAL REGISTRATION NUMBER:ClinicalTrials.gov registry (NCT03298633).

Dataset Information

Rescue of failed oocyte activation after ICSI in a mouse model of male factor infertility by recombinant phospholipase C?.

Publications

Rescue of failed oocyte activation after ICSI in a mouse model of male factor infertility by recombinant phospholipase Cζ.

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