Piezo-assisted ICSI improves fertilization and blastocyst development rates compared with conventional ICSI in women aged more than 35 years

Polyvinylpyrrolidone can prevent oolemma lysis caused by abnormal rupture of the plasma membrane in Piezo-ICSI

The aim of this study was to investigate whether it is possible to prevent oolemma lysis after Piezo-assisted intracytoplasmic sperm injection (Piezo-ICSI) caused by abnormal membrane rupture. A total of 489 mature oocytes were obtained from 85 patients who underwent Piezo-ICSI in an infertility clinic. Inseminated oocytes were classified into the following two groups: normal rupture and abnormal rupture, and a portion of abnormally ruptured oocytes was randomly exposed to 7% PVP solution. Normal fertilization rate, degeneration rate, proportion of high-quality embryos on day 3, blastocyst formation, and morphologically high-quality blastocysts were compared. Abnormal rupture was defined as cytoplasmic membrane rupture before piezo pulse driving. Among the abnormal rupture groups, the normal fertilization and degeneration rates were compared between the high-stretched (ruptured at ≥ 50% during oocyte membrane stretching) and low-stretched (< 50% position) oocytes.The degeneration rate was significantly higher in abnormally ruptured oocytes than in normally ruptures oocytes (14.3% vs 1.3%, p < 0.001), and there was no significant difference in embryonic development after fertilization. PVP treatment immediately after oolemma rupture significantly decreased the degeneration rate (6.0% vs 19.7%, p = 0.031) and increased the normal fertilization rate. Similarly, there were no significant differences in the developmental potential. Furthermore, pregnancy outcome data showed no significant differences in pregnancy and live birth rates. The degeneration rate was reduced by treating low-stretched oocytes with PVP.Exposure to polyvinylpyrrolidone (PVP) immediately after abnormal membrane rupture represents an effective strategy to prevent oocyte degeneration. This is the first study to propose a strategy for the prevention of oocyte degeneration in Piezo-ICSI. These findings are expected to reduce the oocyte degeneration rate and increase normal fertilization rate as well as assist patients who can only acquire oocytes with weak plasma membranes.

A brief history of technical developments in intracytoplasmic sperm injection (ICSI). Dedicated to the memory of J.M. Cummins

Intracytoplasmic sperm injection (ICSI) is an assisted reproductive technology for treatment of severe male infertility introduced into clinical practice in 1992. This review provides a brief history of the development of ICSI by acknowledging major developments in the field. The review addresses key developments in pre-clinical and early studies, how ICSI compares with in vitro fertilisation, long-term consequences, how the mechanistic approach to ICSI has changed in both manual and semi-automated approaches, and how sperm selection procedures are integrated into ICSI. From the beginnings using animal models in the 1960-1970s, the development of ICSI is a remarkable and transformative success story. Indeed, its broad use (70% of cycles globally) exceeds the need required for treating infertile males, and this remains a controversial issue. There remain questions around the long-term health impacts of ICSI. Furthermore, advances in automation of the ICSI procedure are occurring. An estimated 6million children have been born from the ICSI procedure. With further automation of sperm selection technologies, coupled with automation of the injection procedure, it is likely that the proportion of children born from ICSI will further increase.

Improved fertilization, degeneration, and embryo quality rates with PIEZO-intracytoplasmic sperm injection compared with conventional intracytoplasmic sperm injection: a sibling oocyte split multicenter trial

OBJECTIVE

To investigate whether PIEZO-intracytoplasmic sperm injection (PIEZO-ICSI) increases the fertilization rate, decreases the degeneration rate, and increases the utilization rate per oocyte injected compared with conventional intracytoplasmic sperm injection (ICSI).

DESIGN

Sibling oocyte split multicenter trial.

SETTING

Fertility clinics.

PATIENTS

Women with a diagnosis of infertility who used ICSI as their method of insemination and had ≥6 mature oocytes for injection.

INTERVENTIONS

Participants had their mature oocyte cohort divided, where half were injected using conventional ICSI and the other half were injected using PIEZO-ICSI. For patients with an uneven oocyte number, the extra oocyte was injected using conventional ICSI. The injection technique used first was also randomized to ensure that there was no bias due to order of injection.

MAIN OUTCOME MEASURE

The primary outcome measure was the fertilization rate after injection.

RESULTS

A total of 108 patients underwent a sibling split use of conventional ICSI and PIEZO-ICSI. The fertilization rate was 71.6% in PIEZO-ICSI, which significantly increased compared with that in conventional ICSI 65.6%. In addition, the oocyte degeneration rate decreased in PIEZO-ICSI compared with that in conventional ICSI (6.3% vs. 12.1% respectively), and the blastocyst quality increased, as measured by the number of grade A and B quality blastocysts present on day 5 of development (33.3% vs. 27.5%). No significant differences in the aneuploidy or utilization rate, clinical pregnancy, or live birth outcome after single embryo transfer were noted between the two injection techniques.

CONCLUSIONS

This trial supports the possibility that PIEZO-ICSI increases the fertilization rates, decreases the oocyte degeneration rates, and increases the blastocyst quality compared with conventional ICSI; however, it does not appear to influence the clinical pregnancy or live birth rate per transfer.

CLINICIAN TRIAL REGISTRATION NUMBER

Australian and New Zealand Clinical Trial Registry ACTRN12620000407998.

Evolution of intracytoplasmic sperm injection: From initial challenges to wider applications

Background

In vitro fertilization (IVF) has revolutionized infertility treatment. Nevertheless, male infertility requires more effective solutions. In 1992, the first-ever case of human birth via intracytoplasmic sperm injection (ICSI) was reported. ICSI involves microscopically injecting a sperm into an ovum. Successful ICSI has become a reliable therapy for couples facing infertility, a significant milestone. However, it has also introduced various challenges. This study also delves into ethical dilemmas arising from widespread ICSI use.

Methods

This review traces the history of ICSI, presenting pioneering attempts, first successful attempts, and critical reports on account of the initial skepticism toward the technology. The review also focuses on chronological progress until ICSI was recognized as effective and became widely applied.

Main findings

The review reveals that ICSI, although transformative, presents challenges. Successes include addressing male infertility and aiding fertilization. However, concerns arise regarding optimal sperm and embryo selection, genetic mutations, and long-term health implications. Ethical considerations surrounding ICSI's broad applications also surface.

Conclusions

Despite its success and effectiveness, ICSI is still evolving as a therapeutic method. By comprehensively evaluating the historical progress and the current status of ICSI and exploring its future prospects, this study highlights the importance of ICSI in infertility treatment.

First babies conceived with Automated Intracytoplasmic Sperm Injection

RESEARCH QUESTION

Can an automated sperm injection robot perform Automated Intracytoplasmic Sperm Injection (ICSIA) for use in human IVF?

DESIGN

The ICSIA robot automated the sperm injection procedure, including injection pipette advancement, zona pellucida and oolemma penetration with piezo pulses, and pipette removal after sperm release. The robot was first tested in mouse, hamster and rabbit oocytes, and subsequently using discarded human oocytes injected with microbeads. A small clinical pilot trial was conducted with donor oocytes to study the feasibility of the robot in a clinical setting. The ICSIA robot was controlled by engineers with no micromanipulation experience. Results were compared with those obtained with manual ICSI conducted by experienced embryologists.

RESULTS

The ICSIA robot demonstrated similar results to the manual procedure in the different animal models tested as well as in the pre-clinical validations conducted in discarded human oocytes. In the clinical validation, 13 out of 14 oocytes injected with ICSIA fertilized correctly versus 16 out of 18 in the manual control; eight developed into good-quality blastocysts versus 12 in the manual control; and four were diagnosed as chromosomally normal versus 10 euploid in the manual control. Three euploid blastocysts from the ICSIA robot group have been transferred into two recipients, which resulted in two singleton pregnancies and two babies born.

CONCLUSIONS

The ICSIA robot showed high proficiency in injecting animal and human oocytes when operated by inexperienced personnel. The preliminary results obtained in this first clinical pilot trial are within key performance indicators.

Imaging the subcellular viscoelastic properties of mouse oocytes

In recent years, cellular biomechanical properties have been investigated as an alternative to morphological assessments for oocyte selection in reproductive science. Despite the high relevance of cell viscoelasticity characterization, the reconstruction of spatially distributed viscoelastic parameter images in such materials remains a major challenge. Here, a framework for mapping viscoelasticity at the subcellular scale is proposed and applied to live mouse oocytes. The strategy relies on the principles of optical microelastography for imaging in combination with the overlapping subzone nonlinear inversion technique for complex-valued shear modulus reconstruction. The three-dimensional nature of the viscoelasticity equations was accommodated by applying an oocyte geometry-based 3D mechanical motion model to the measured wave field. Five domains-nucleolus, nucleus, cytoplasm, perivitelline space, and zona pellucida-could be visually differentiated in both oocyte storage and loss modulus maps, and statistically significant differences were observed between most of these domains in either property reconstruction. The method proposed herein presents excellent potential for biomechanical-based monitoring of oocyte health and complex transformations across lifespan. It also shows appreciable latitude for generalization to cells of arbitrary shape using conventional microscopy equipment.

The effect of early irregular cell division of human embryos on blastocyst euploidy: considerations from the subsequent development of the blastomeres by direct or reverse cleavage

OBJECTIVE

To investigate whether blastocysts that divide irregularly reduce subsequent blastocyst euploidy.

DESIGN

Retrospective study.

SETTING

Private clinic.

PATIENT(S)

A total of 122 blastocysts for which consent for disposal and research use was obtained.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Results of next-generation sequencing analysis of the blastocysts and whether blastomeres by normal or irregular divisions subsequently participated in blastocyst formation or not.

RESULT(S)

The embryos were classified according to their dynamics until the second cleavage. The blastocyst euploidy rates were 33.3% (19/57) in the normal cleavage (NC) group, 38.3% (18/47) in the direct cleavage (embryos with one cell dividing into 3 cells) (DC) group, and 72.2% (13/18) in the reverse cleavage (RC) (embryos with fused cells once divided) group. The rate of the RC group was significantly higher than that of the NC group. The blastocyst participation rate of the blastomeres were 95.6% in the NC group and 56.5% in that derived from DC of the first cleavage, and 91.7% in that of blastomeres derived from normal division of the second cleavage and 53.6% in that derived from DC of the second cleavage, both of which were significantly lower in the latter. In the RC group, the rates of fused and nonfused blastomeres were 62.1% and 87.5%, respectively, with no significant difference.

CONCLUSION(S)

The blastomeres generated by DC were often excluded from blastocyst formation, and we speculate that this is one reason why their division does not reduce blastocyst euploidy. The association between RC and euploidy of blastocysts merits further study.

PIEZO-ICSI increases fertilization rates compared with conventional ICSI in patients with poor prognosis

PURPOSE

Limited research has been published comparing PIEZO-ICSI with conventional ICSI. While positive effects have been documented in improving fertilization and degeneration, the outcomes in patients with previous poor results from conventional ICSI remain unclear. It is hypothesized that these patients may benefit the most from this form of insemination.

METHODS

This retrospective paired within-patient cohort study investigated patients (n=72) undertaking PIEZO-ICSI after a previous conventional ICSI cycle resulted in poor outcomes (including low fertilization (<50%), high degeneration (>15%), and/or poor embryo development and utilization). Patients required at least five oocytes collected in both cycles and a period of less than 2 years between the cycles. The outcomes of both cycles were compared in respect to fertilization, degeneration, embryo utilization, and pregnancy rates. Further analyses were applied to patients <38 and ≥38 years of age, with <50% or ≥50% fertilization with conventional ICSI and with <20% or ≥20% utilization with conventional ICSI.

RESULTS

PIEZO-ICSI resulted in significantly higher fertilization (61.9% vs 45.3%, P<0.0001) and lower degeneration (7.7% vs 18.2%, P=0.0001) when compared to the conventional ICSI cycles. The greatest benefit was seen in patients who had less than 50% fertilization or <20% utilization in their conventional ICSI cycle, with improvements in fertilization and degeneration rates resulting in a significantly higher number of embryos utilized (frozen or transferred) per cycle.

CONCLUSIONS

PIEZO-ICSI improved fertilization, degeneration, and utilization rates in patients with previous poor outcomes from conventional ICSI. The number of embryos available for use per cycle was also increased. Further significant improvements were achieved in patients who exhibited poor fertilization (<50%) or low utilization (<20%) from conventional ICSI.

Bovine ICSI: limiting factors, strategies to improve its efficiency and alternative approaches

Intracytoplasmic sperm injection (ICSI) is an assisted reproductive technique mainly used to overcome severe infertility problems associated with the male factor, but in cattle its efficiency is far from optimal. Artificial activation treatments combining ionomycin (Io) with 6-dimethylaminopurine after piezo-ICSI or anisomycin after conventional ICSI have recently increased the blastocyst rate obtained. Compounds to capacitate bovine spermatozoa, such as heparin and methyl-β-cyclodextrin and compounds to destabilize sperm membranes such as NaOH, lysolecithin and Triton X-100, have been assessed, although they have failed to substantially improve post-ICSI embryonic development. Disulfide bond reducing agents, such as dithiothreitol (DTT), dithiobutylamine and reduced glutathione, have been assessed to decondense the hypercondensed head of bovine spermatozoa, the two latter being more efficient than DTT and less harmful. Although piezo-directed ICSI without external activation has generated high fertilization rates and modest rates of early embryo development, other studies have required exogenous activation to improve the results. This manuscript thoroughly reviews the different strategies used in bovine ICSI to improve its efficiency and proposes some alternative approaches, such as the use of extracellular vesicles (EVs) as 'biological methods of oocyte activation' or the incorporation of EVs in the in vitro maturation and/or culture medium as antioxidant defence agents to improve the competence of the ooplasm, as well as a preincubation of the spermatozoa in estrous oviductal fluid to induce physiological capacitation and acrosome reaction before ICSI, and the use of hyaluronate in the sperm immobilization medium.

Value of Meiotic Spindle Imaging on Fertilization and Embryo Development Following Human Oocyte Piezo-ICSI

Background: The objective of this study was to investigate accurately the effect of the meiotic spindle imaging of human oocytes on their fertilization and embryo development by using the Piezo-ICSI.

Methods: We retrospectively assessed 529 oocytes with the first polar body retrieved from 124 infertile couples (147 cycles) who attended our clinic between May 2016 and December 2018. Of these, 489 oocytes (92.4%) with visible meiotic spindle comprised the Spindle (+) group and 40 oocytes (7.6%) not observed meiotic spindle comprised the Spindle (−) group. The meiotic spindle was imaged using polarized light microscopy. The rates of fertilization, high-quality day-3 embryo, day-5 blastocyst, and high-quality day-5 blastocyst were evaluated in both groups.

Results: The fertilization rates of Spindle (+) and Spindle (−) were 92.0% (450/489) and 70.0% (28/40), respectively; high-quality day-3 embryo rates were 62.9% (283/450) and 35.7% (10/28); day-5 blastocyst rates were 53.7% (205/382) and 32.1% (9/28); high-quality day-5 blastocyst rates were 29.8% (114/382) and 3.6% (1/28). Fertilization, high-quality day-3 embryo, day-5 blastocyst, and high-quality day-5 blastocyst rates were significantly higher in the Spindle (+) group than in the Spindle (−) group.

Conclusion: Spindle imaging (i.e., oocytes with a visible meiotic spindle or with not observed meiotic spindle) influences the outcome of Piezo-ICSI in human oocytes, including fertilization and embryo development. To our knowledge, this study is the first to evaluate the effect of meiotic spindle imaging on fertilization or embryo development among oocytes after Piezo-ICSI. The meiotic spindle imaging could be the indicator for the quality management of medical doctors and embryologists.

Developmental trajectory of monopronucleated zygotes after in vitro fertilization when they include both male and female genomes

OBJECTIVE

To examine the cause of monopronucleated zygote (1PN) formation that includes both maternal and paternal genomes.

DESIGN

Retrospective cohort study.

SETTING

Private fertility clinic.

PATIENT(S)

A total of 44 1PN and 726 2-pronuclear zygotes from 702 patients were observed using 2 different time-lapse observation systems.

INTERVENTION(S)

Previously recorded time lapse data were reviewed to examine the mechanism of 1PN formation.

MAIN OUTCOME MEASURE(S)

The distance between the position of the second polar body extrusion and the fertilization cone or epicenter/starting position of the cytoplasmic wave was measured, and the consequent data were analyzed. Cytoplasmic waves were confirmed using vector analysis software.

RESULT(S)

The cut-off value for the difference in the distance between the position of the second polar body extrusion and the fertilization cone or the epicenter/starting position of the cytoplasmic wave was 17 μm (AUC: 0.987, 95% CI: 0.976-0.999) for the Embryo Scope and 18 μm (AUC: 0.972, 95% CI: 0.955-0.988) for the iBIS time-lapse observation systems.

CONCLUSION(S)

In this study, it was found with a high degree of accuracy that a monopronucleus is formed when the fusion of the sperm takes place within 18 μm from the point of the second polar body extrusion. The theoretical chance of 1PN occurrence after in vitro fertilization is 2.7% when the sperm is considered to be fused anywhere in the plasma membrane of an oocyte.

PIEZO-ICSI increases fertilization rates compared with standard ICSI: a prospective cohort study

RESEARCH QUESTION

Is PIEZO-intracytoplasmic sperm injection (ICSI) coupled with a new novel operational fluid (perfluoro-n-octane) superior to standard ICSI?

DESIGN

A cohort of patients (n = 69) undertaking microinjection were recruited between January and November 2019 and were then prospectively case-matched. Patients required six or more mature oocytes for inclusion in the study. PIEZO-ICSI uses high-speed microinjection drilling to penetrate the zona and oolemma and deposit the spermatozoa into the cytoplasm, compared with the traditional 'cutting' action of ICSI. The primary outcome was fertilization, with secondary outcomes including oocyte degeneration, abnormal fertilization, embryo cryopreservation and embryo utilization.

RESULTS

PIEZO-ICSI resulted in significantly higher fertilization rates (80.5 ± 2.4% vs 65.8 ± 2.3%, P < 0.0001) and lower oocyte degeneration rates (4.4 ± 1.3% vs 8.6 ± 1.2%, P = 0.019) and abnormal fertilization rates (2.9 ± 1.1% vs 7.4 ± 1.1%; P = 0.003) compared with standard ICSI. This improvement in fertilization was of most benefit in patients aged ≥38 years. This increase in fertilization increased the number of good quality embryos that were available for cryopreservation/transfer (3.8 ± 0.2 vs 3.1 ± 0.2; P = 0.038), such that patients on average had one extra usable embryo per cycle compared with standard ICSI. There were no differences to Day 5 embryo development or clinical pregnancy from fresh embryo transfer (57.1% PIEZO-ICSI vs 60.0% ICSI) between microinjection methods, although pregnancy outcomes were underpowered.

CONCLUSIONS

PIEZO-ICSI significantly increased fertilization rates, thereby increasing the number of embryos available for cryopreservation compared with standard ICSI. Further prospective studies assessing cumulative pregnancy rates are warranted.

Evaluation of the effect of piezo-intracytoplasmic sperm injection on the laboratory, clinical, and neonatal outcomes

PURPOSE

Limited research has been published on the effect of piezo-assisted intracytoplasmic sperm injection (P-ICSI). We evaluated the effect of P-ICSI on the laboratory, clinical, and neonatal outcomes.

METHODS

This retrospective study was based on the data collected between April 2011 and October 2016. Total 1348 mature oocytes from 145 patients were analyzed. Laboratory, clinical, and neonatal outcomes of those given conventional intracytoplasmic sperm injection (C-ICSI) and those administered P-ICSI were examined.

RESULTS

P-ICSI showed significantly more favorable results, with a survival rate of 97.0% (C-ICSI: 94.1%, P < .010) and a fertilization rate of 83.5% (C-ICSI: 70.6%, P < .001). There were no differences in the blastocyst development rate, implantation rate, miscarriage rate, live birth rate, gestational age, birth weight, proportion of male neonates, cesarean section rate, and congenital abnormalities between the two patient groups.

CONCLUSIONS

Our comparison of P-ICSI with C-ICSI showed that P-ICSI significantly improved the survival and fertilization.