Use of laser-assisted intracytoplasmic sperm injection (ICSI) in patients with a history of poor ICSI outcome and limited metaphase II oocytes

Identifying optimal puncture position by a real-time image analysis for Piezo-ICSI: a prospective randomized sibling oocyte study

RESEARCH QUESTION

Would the use of the intracytoplasmic sperm injection (ICSI) position detector (IPD) make it possible to identify the optimal puncture position on oolemma during Piezo-ICSI and reduce oocyte degeneration and unintentional membrane rupture (UMR)?

DESIGN

This sibling oocyte study included 917 inseminated oocytes from 113 infertile patients undergoing Piezo-ICSI. Oocytes were randomly divided into two groups: with or without IPD. The rates of UMR, degeneration, fertilization and embryonic development were compared between the two groups. As a secondary analysis, non-IPD oocytes were retrospectively assessed as appropriate or non-appropriate injection sites and analysed alongside prospective 'appropriate' injections.

RESULTS

The rates of UMR (7.0% versus 12.9%, P = 0.004) and degeneration (2.4% versus 6.1%, P < 0.01 = 0.008) were significantly lower in the IPD group than in the non-IPD group. No significant differences, however, were observed in the rates of fertilization (two pronuclei, 83.8% versus 78.9%), blastocyst formation (48.5% versus 48.8%) or good-quality blastocysts (22.5% versus 20.5%). Additionally, no significant differences were observed in the rates of pregnancy (29.4% versus 35.1%) or live births (26.5% versus 29.7%) in a single embryo transfer setting with or without IPD. Comparing all 'appropriate' injections with 'non-appropriate' injections also showed a significantly decreased rate of UMR and degeneration (both P ≤ 0.001).

CONCLUSIONS

The present study demonstrated that a real-time image analysis during Piezo-ICSI markedly reduced oocyte degeneration by avoiding areas associated with a high risk of UMR. Therefore, IPD may increase the number of embryos available for treatment.

Optimal puncture position for ICSI can be detected by image analysis using Local Binary Pattern

RESEARCH QUESTION

One of the problems during the intracytoplasmic sperm injection (ICSI) procedure is unintentional membrane rupture (UMR), which often predisposes to subsequent oocyte degeneration. Can the ICSI Position Detector (IPD) be useful in identifying the optimal puncture location to prevent UMR during ICSI?

DESIGN

A total of 709 mature oocytes were included. Conventional ICSI was carried out and images were recorded by IPD; these were analysed retrospectively.

RESULTS

Inseminated oocytes were retrospectively grouped according to the IPD, irrespective of whether oolemma was punctured at an area in which UMR is likely (non-appropriate group) or unlikely (appropriate group). In the appropriate group, rates of UMR (5.3% versus 18.2%) and degeneration (2.5% versus 8.7%) were significantly lower than those of the non-appropriate group, whereas rate of fertilization (87.1% versus 69.7%) was significantly higher than those of the non-appropriate group, respectively (P < 0.001). These differences remained even after propensity score matching to adjust for potential differences in characteristics between appropriate and non-appropriate groups.

CONCLUSIONS

This study demonstrated that the IPD is useful to identify the optimal puncture location to circumvent UMR during the ICSI procedure, resulting in reduced UMR and oocyte degeneration, thereby, generating more embryos available for transfer or cryopreservation.

A randomized controlled trial of laser-assisted ICSI

STUDY QUESTION

Does the use of a laser to open the zona pellucida during ICSI (laser assisted or LA-ICSI) improve oocyte survival, embryo development and clinical outcomes?

SUMMARY ANSWER

Compared to conventional ICSI, LA-ICSI increased rates of oocyte survival and some aspects of embryo development but it did not alter the ongoing pregnancy rate; after adjusting for oocyte survival, there was no beneficial effect of LA-ICSI on embryo development and utilization.

WHAT IS KNOWN ALREADY

Oocyte degeneration occurs in a 10th of mature oocytes after ICSI. Pilot studies suggest that LA-ICSI may improve oocyte survivability.

STUDY DESIGN, SIZE, DURATION

In a randomized controlled trial, 966 couples (16 122 metaphase II oocytes) were allocated to receive LA-ICSI (intervention) or conventional ICSI (control) between 17 September 2018 and 5 August 2019. Oocyte survival (primary endpoint), embryo development and ongoing pregnancy rates were compared.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Couples included in this study were recommended for ICSI due to female or male factor, unexplained infertility or a combination of factors. Patients were ineligible to participate in the study if they had uterine abnormality including thin endometrium, recurrent pregnancy loss, endometriosis or a severe medical condition. Concealed randomization to LA-ICSI or conventional ICSI, allocated in a 1:1 ratio, took place on stimulation Day 1 with replacement of blastocysts on only Day 5. The primary endpoint was oocyte survival with membrane integrity 24 h after the ICSI procedure. The sample size was estimated to detect a 3% increase in oocyte survival after LA-ICSI with 99% power at a 1% significance level. This also permitted the detection of 10% increase in ongoing pregnancy rate after LA-ICSI with 85% power at 5% alpha level. We used Poisson regression with zero-inflation for count data to estimate relative risk (RR) with 95% CI and logistic regression for clinical outcomes to estimate odds ratio (OR) with 95% CI. Both models adjusted for age as a covariate.

MAIN RESULTS AND THE ROLE OF CHANCE

Compared with conventional ICSI, LA-ICSI resulted in a higher number of surviving oocytes (RR 1.08, 95% CI 1.05-1.12, P < 0.001), as well as a higher number of fertilized oocytes (RR 1.08, 95% CI 1.04-1.13, P < 0.001) and utilizable blastocysts (RR 1.09, 95% CI 1.04-1.15, P < 0.001). Sensitivity analyses adjusted for oocyte survival showed no between-group difference in utilizable blastocysts (OR 1.01, 95% CI 0.95-1.08, P = 0.73) and by calculating the mean rate, a reduction in utilizable blastocysts was shown (RR 0.95, 95% CI 0.94-0.97, P < 0.001). Ongoing pregnancy showed no between-group difference (LA-ICSI 179/489 (37%) vs ICSI 201/477 (42%), OR 0.79, 95% CI 0.61-1.03, P = 0.09).

LIMITATIONS, REASONS FOR CAUTION

It was not possible to blind the embryologists involved in the ICSI procedure. However, there was concealment of randomization and blinding of outcome assessments reducing the risk of selection and measurement bias.

WIDER IMPLICATIONS OF THE FINDINGS

A beneficial effect of LA-ICSI on oocyte survival should be shown to improve clinical outcomes, before its use in clinical practice is justified.

STUDY FUNDING/COMPETING INTEREST(S)

The study received no funding, and the authors declare that there are no conflicts of interest.

TRIAL REGISTRATION NUMBER

NCT03665103.

TRIAL REGISTRATION DATE

11 September 2018.

DATE OF FIRST PATIENT'S ENROLMENT

17 September 2018.

Controlled hatching at the prescribed site using femtosecond laser for zona pellucida drilling at the early blastocyst stage

PURPOSE

To study whether the application of femtosecond laser pulses for zona pellucida (ZP) drilling of blastocysts at the embryonic or abembryonic poles can promote hatching to start immediately through the hole formed and ensure high hatching rates and embryo viability.

METHODS

Mouse blastocyst (E3.5) ZP were microdissected with femtosecond laser pulses (514-nm wavelength, 280-fs pulse duration, 2.5-kHz repetition rate) close to the trophoblast or inner cell mass (ICM). The sizes of the holes formed were in the range of 4.5-8.5 μm. Additional longitudinal incisions (5-7-μm long) on either side of the hole were created to determine whether hatching had started at the correct position. Embryos post-laser-assisted ZP drilling and intact embryos were cultured under standard conditions for 2 days; embryo quality was assessed twice daily. The hatching rates and in vitro and in vivo implantation rates (only for embryos with ZP dissected close to the ICM) were estimated.

RESULTS

Femtosecond laser-assisted ZP drilling at the early blastocyst stage facilitated embryo hatching to start at the artificial opening with probability approaching 100%. Despite the artificial opening's small size, no embryo trapping during hatching was observed. Both experimental groups had higher hatching rates than the control groups (93.3-94.7% vs. 83.3-85.7%, respectively). The in vitro implantation rate was comparable with that of the control group (92.3% vs. 95.4%). No statistically significant differences were obtained in the in vivo implantation rates between the experimental and control groups.

CONCLUSIONS

Blastocyst-stage femtosecond laser microsurgery of ZP is fast and delicate and enables the hatching process to be initiated in a controlled manner through a relatively small opening, with no embryo trapping.

Strategies to improve fertilisation rates with assisted conception: a systematic review

Successful fertilisation is one of the key steps determining success of assisted conception. Various factors including sperm or oocyte pathology and environmental factors have a significant impact on fertilisation rates. This systematic review is aimed to evaluate the existing evidence about factors affecting fertilisation and strategies to improve fertilisation rates. A literature search was performed using Ovid MEDLINE ® (Jan 1950-April 2016), EMBASE (Jan 1950-April 2016), Ovid OLDMEDLINE ®, Pre-MEDLINE (Jan 1950-April 2016) and the Cochrane Library. Relevant key words were used to combine sets of results and a total 243 papers were screened. Only qualitative analysis was performed, as there was major heterogeneity in study design and methodology for quantitative synthesis. Factors affecting fertilisation were divided into sperm- and oocyte-related factors. The methods to improve fertilisation rates were grouped together based on the approach used to improve fertilisation rates. Optimising laboratory condition and procedural effects in techniques is associated with improved fertilisation rates. Various techniques are described to improve fertilisation rates including assisted oocyte activation, physiological intracytoplasmic sperm injection (PICSI) and intracytoplasmic morphologically selected sperm injection (IMSI). This review highlights the promising strategies under research to enhance fertilisation rates. Adequately powered multicentre randomised trials are required to evaluate these techniques before considering clinical application.

Effect of Ca Ionophore On Blastocyst Production Following Intracytoplasmic Sperm Injection in Caprine Oocytes

The aim of the present investigation was to study the effect of calcium ionophore activation on blastocyst production following intracytoplasmic sperm injection (ICSI) in in vitro-matured Caprine oocytes. A total of 470 in vitro-matured oocytes were selected and randomly divided in to three groups. Cumulus oocyte complexes (COCs) recovered by slicing the Caprine ovaries were matured in TCM199 supplemented with 10% foetal bovine serum (FBS) + 10% follicular fluid + FSH (5 μg/ml) + LH (10 μg/ml) + estradiol (1 μg/ml) + EGF (10 ng/ml) + BSA (3 mg/ml) for 27 h in humidified atmosphere at 38.5°C with 5% CO2 in CO2 incubator. After 27 h of culture, selected COCs (n = 470) were separated from cumulus cells by treating with 0.1% hyaluronidase enzyme and passing repeatedly through a fine pipette and randomly divided into three groups. In group 1, (n = 168) matured oocytes were injected with injection micropipette without sperm as control. In group 2, (n = 152) capacitated spermatozoa were injected into cytoplasm of in vitro-matured oocytes through injection micropipette. In group 3, (n = 150) capacitated spermatozoa were injected into cytoplasm of in vitro-matured oocytes through injection micropipette and then activated with 5 μm Ca ionophore for 5 min. The oocytes of all groups were then culture in RVCL media for embryo development. The cleavage rate was observed after 48-72 h of injection. The cleavage rate and blastocyst production in group 1, 2 and 3 were 0.00 and 0.00, 18.42 and 3.57 and 61.33% and 16.30%, respectively. The result indicated that mechanical activation failed to induce cleavage in in vitro-matured Caprine oocytes, whereas chemical activation of intracytoplasmic sperm-injected in vitro-matured Caprine oocytes showed significantly higher cleavage rate and blastocyst production as compare to non-activated oocytes.

Intracytoplasmic sperm injection (ICSI) in small ruminants

Small ruminants are an important component of the global production systems of meat and wool, and their reproductive biology is well known. However, the incorporation of assisted reproduction techniques (ART) in the production systems of small ruminants is not as well developed as for other domestic species. Normally, production systems that incorporate ARTs are restricted to artificial insemination or in vivo embryo transfer. Intracytoplasmic sperm injection (ICSI) is one of the ARTs techniques reported for small ruminants and consists of the injection of spermatozoa inside an oocyte, bypassing the natural process of sperm-oocyte interaction. In goats and sheep, there are few live births by ICSI reported, with no reports from other species of small ruminants. Currently, there has not been intensive research about ICSI in small ruminants. However, ICSI has potentially important applications in animal production systems, primarily its use with semen of valued animals, with epididymal sperm, in the fertilization of prepubertal or cryopreserved oocytes. Other applications include more advanced techniques, such as transgenic-ICSI or its combination with spermatogonial transplantation. In this article, we review the "state of the art" of this technique in small ruminants including its historical development, research needs for its improvement and future applications.

Efficiency of laser-assisted intracytoplasmic sperm injection in a human assisted reproductive techniques program

OBJECTIVE

Laser-assisted intracytoplasmic sperm injection (LA-ICSI), also known as micro-opening or thinning of the zona pellucida (ZP) prior to ICSI, may help to reduce mechanical damage to the oocyte during the procedure. The aim of the present study was to evaluate and analyze the efficacy of our institutional LA-ICSI program, which features laser-assisted ZP thinning prior to ICSI, in comparison with conventional ICSI (C-ICSI), performed on patients with different clinical characteristics.

METHODS

Patients undergoing a total of 212 ICSI cycles were randomly divided into an LA-ICSI group (106 cycles) and a conventional ICSI group (106 cycles). To reduce tissue damage, we thinned the ZP by approximately 70%, using a laser, before ICSI. Patients thus treated formed the LA-ICSI group. Comparisons included the morphological quality of transferred embryos, blastocyst development of the remaining embryos, and clinical pregnancy, in terms of ICSI method and patient characteristics.

RESULTS

Fertilization, development of remaining embryos, and pregnancy rate were significantly higher in the LA-ICSI group compared with the C-ICSI group. Fertilization, embryonic development, and the pregnancy rate were all improved in younger patients (<38 years of age) and in those who underwent a low number of IVF-ET attempts (<3 trials). In addition, the pregnancy rate was increased in older patients.

CONCLUSION

LA-ICSI may be useful in improving the chance of pregnancy in all ICSI patients.