Intracytoplasmic morphologically selected sperm injection results in improved clinical outcomes in couples with previous ICSI failures or male factor infertility: a meta-analysis

Sperm Separation and Selection Techniques to Mitigate Sperm DNA Damage

Semen preparation and sperm selection techniques exploit the morphological and physiological characteristics of sperm function, including motility, morphology, density, and maturity, as reflected by their cell-surface charge and the expression of hyaluronan receptors. The various methods employed have a common purpose of mimicing sperm selection within the female reproductive tract and, thereby, increasing the likelihood that oocytes will be fertilised by spermatozoa with intact nuclear DNA and a normal genome. Indeed, the paternal genome is relevant to embryonic genome activation and blastocyst development, and has a fundamental impact upon successful implantation, ongoing pregnancy and live birth. The clinical use of both well-established and some more recently developed techniques is discussed in this comparative clinical review of sperm separation from seminal plasma and selection for insemination.

Sperm Selection Procedures for Optimizing the Outcome of ICSI in Patients with NOA

Retrieving spermatozoa from the testicles has been a great hope for patients with non-obstructive azoospermia (NOA), but relevant methods have not yet been developed to the level necessary to provide resolutions for all cases of NOA. Although performing testicular sperm extraction under microscopic magnification has increased sperm retrieval rates, in vitro selection and processing of quality sperm plays an essential role in the success of in vitro fertilization. Moreover, sperm cryopreservation is widely used in assisted reproductive technologies, whether for therapeutic purposes or for future fertility preservation. In recent years, there have been new developments using advanced technologies to freeze and preserve even very small numbers of sperm for which conventional techniques are inadequate. The present review provides an up-to-date summary of current strategies for maximizing sperm recovery from surgically obtained testicular samples and, as an extension, optimization of in vitro sperm processing techniques in the management of NOA.

The possibility of integrating motile sperm organelle morphology examination (MSOME) with intracytoplasmic morphologically-selected sperm injection (IMSI) when treating couples with unexplained infertility

Purpose

To examine the efficacy of motile sperm organelle morphology examination (MSOME) and intracytoplasmic morphologically-selected sperm injection (IMSI) for unexplained infertility.

Methods

This historical study, included 271 couples with primary, unexplained infertility/male subfertility, treated at an outpatient, IVF clinic, 2015–2018. These couples underwent MSOME after ≥3 failed intrauterine insemination (IUI) cycles and ≥1 failed IVF-ICSI cycle. They proceeded to intracytoplasmic morphologically-selected sperm injection (IMSI) within 6 months of MSOME. IMSI is conducted on the day of oocyte pick-up with a fresh semen sample. Pregnancy and delivery rates were analyzed.

Results

The cohort was divided based on percentage of normal cells at MSOME: Group A included 55 with no normal cells, Group B, 184 with 0.5%≤ normal cells ≤1.5% and Group C, 32 with ≥2% normal cells. Normal spermatozoa were found in 49 (89%) of Group A after extensive search. Group A had higher pregnancy rate (62.7%) compared to B (47.2%, P = 0.05) and C (28.1%, P = 0.002). Group B had higher pregnancy rate than C (p = 0.045). Delivery rate was higher in Group A (52.1%) compared to B (34.1%, p = 0.023) and C (21.9%, p = 0.007). Pregnancy and delivery rates were higher in A compared to B+C (p = 0.018, p = 0.01, respectively).

Conclusions

MSOME may be useful for evaluating unexplained infertility. IMSI can be recommended for men with <2% normal spermatozoa at MSOME.

Effects of the sperm DNA fragmentation index on the clinical and neonatal outcomes of intracytoplasmic sperm injection cycles

Background

Most studies have mainly focused on the effects of the sperm DNA fragmentation index (DFI) on fertilization, embryonic developmental potential and aneuploidy, pregnancy and abortion rates after in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) and have remained controversial. However, few studies have reported the effects of sperm DFI on neonatal outcomes, including stillbirths, neonatal deaths, sex, gestational age, prematurity, birthweight, low birth weight (LBW) and birth defects in newborns. Our objective was to evaluate the effects of sperm DFI on the clinical and neonatal outcomes of ICSI cycles.

Methods

This retrospective study analysed a total of 2067 oocyte retrieval, 1139 transfer and 713 delivery cycles from conventional ICSI cycles, including 301, 469, and 214 live-born infants in groups segregated according to sperm DFI as the < 15%, 15–30% and >  30% groups, respectively. The clinical and neonatal outcomes were compared among the three groups.

Results

Sperm DFI did not significantly affect the rates of fertilization, clinical pregnancy, miscarriage or ongoing pregnancy. Sperm DFI did not increase the risk of stillbirths or neonatal deaths. The rates of stillbirths and neonatal deaths were not significantly different among the three groups. The sex, gestational age, prematurity, birthweight and LBW of newborns in the three groups were not significantly affected by sperm DFI. Moreover, sperm DFI did not increase the number of birth defects in children.

Conclusions

Sperm DFI did not affect the clinical or neonatal outcomes of ICSI cycles.

Novel Techniques of Sperm Selection for Improving IVF and ICSI Outcomes

Almost 50% of the infertility cases are due to male factors. Assisted reproductive technologies (ARTs) allow to overcome the incapacity of these patients' spermatozoa to fertilize the oocyte and produce a viable and healthy offspring, but the efficiency of the different techniques has still the potential to improve. According to the latest reports of the European Society of Human Reproduction and Embryology (ESHRE) and the Centers for Disease Control and Prevention of the United States (CDC), the percentages of deliveries per ART cycle in 2014 and 2016 were 21 and 22%, respectively. Among the reasons for this relatively low efficiency, the quality of the spermatozoa has been pointed out as critical, and the presence of high percentages of DNA-damaged spermatozoa in patients' ejaculates is possibly one of the main factors reducing the ARTs outcomes. Thus, one of the main challenges in reproductive medicine is to ensure the highest quality of the spermatozoa used in ARTs, and specifically, in terms of genetic integrity. The latest techniques for the preparation and selection of human spermatozoa are herein discussed focusing on those proven to improve one or several of the following parameters: sperm genetic integrity, fertilization capacity, embryo production, and in vitro survival, as well as pregnancy and delivery rates following in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). In addition, we discuss the potential of techniques developed in non-human mammals that could be further transferred to the clinic.

Live birth and miscarriage rate following intracytoplasmic morphologically selected sperm injection vs intracytoplasmic sperm injection: An updated systematic review and meta-analysis

INTRODUCTION

Intracytoplasmic morphologically selected sperm injection (IMSI) is one of the sperm selection techniques used for assisted reproduction which has been applied for a variety of indications including previously failed fertilization with intracytoplasmic sperm injection (ICSI). A Cochrane review¹ found no difference in outcomes between either modality of sperm selection. Since the Cochrane review was published there have been a further two randomized controlled trials comparing IMSI and ICSI. This systematic review and meta-analysis aims to compare IMSI with ICSI as insemination methods regarding live birth rate and miscarriage rate.

MATERIAL AND METHODS

Systematic review of randomized controlled trials, observational studies and similar reviews in electronic databases published before January 2018.

RESULTS

We found nine randomized controlled trials, evaluating 1610 cycles of in vitro fertilization and 15 observational studies evaluating 1243 cycles of in vitro fertilization. Meta-analysis of the included randomized controlled trials showed no difference in the live birth rate or miscarriage rate between the ICSI and IMSI groups. Meta-analysis of five observational studies showed a significantly higher number of live births in the IMSI group than ICSI group (live birth rate odds ratio 1.47, 95% confidence interval 1.16-4.07), with a moderate degree of heterogeneity (I²  = 41%). Additionally, from six observational studies, a significantly lower miscarriage rate was observed in the IMSI group than in the ICSI group (odds ratio 0.51, 95% confidence interval 0.37-0.70, I²  = 0%).

CONCLUSIONS

Meta-analysis of randomized studies comparing IMSI to ICSI has not shown any difference in live birth rate and miscarriage rate. Meta-analysis of observational studies, which must be interpreted with caution, revealed an increased live birth rate and decreased miscarriage rate with IMSI vs ICSI.

Stain-free interferometric phase microscopy correlation with DNA fragmentation stain in human spermatozoa

Acridine orange (AO) staining is used to diagnose DNA fragmentation status in sperm cells. Interferometric phase microscopy (IPM) is an optical imaging method based on digital holographic microscopy that provides quantitative morphological and refractive index imaging of cells in vitro without the need for staining. We have imaged sperm cells using stain-free IPM in order to estimate different cellular parameters, such as acrosome dry mass and size, in addition to an embryologist evaluation according to the World Health Organization (WHO)-2010 criteria. Following this, the same sperm cells were stained by AO, imaged using a fluorescence confocal microscope and assessed by the AO-emitted color, forming five DNA fragmentation groups. These DNA fragmentation groups were correlated with the embryologist-based classification and the IPM-based morphological parameters. Our results indicate on significant differences in the IPM-based parameters between groups with different fragmentation levels. Based on the validation with AO, we conclude that stain-free IPM images analyzed digitally may assist in selecting sperm cells with intact DNA prior to intracytoplasmic sperm injection. This information may potentially increase percentage of successful pregnancies.

Magnetic-activated cell sorting of non-apoptotic spermatozoa improves the quality of embryos according to female age: a prospective sibling oocyte study

PURPOSE

The main aim of our study was to evaluate the benefit of the use of non-apoptotic spermatozoa selected by magnetic-activated cell sorting (MACS) for ICSI procedures for couples in which the women had good prognoses and the male factor of infertility was teratozoospermia.

METHODS

Twenty-six couples were treated with ICSI after MACS selection of non-apoptotic spermatozoa following a sibling oocyte approach. Half of the oocytes were microinjected with conventionally prepared spermatozoa, and the other half were microinjected with non-apoptotic, MACS-selected spermatozoa. To assess the influence of MACS selection of spermatozoa on the outcomes of the ICSI cycles, the fertilization, embryo quality, pregnancy, and delivery rates were evaluated and compared between the sibling oocyte groups.

RESULTS

When subpopulations of couples according to female age were analyzed, a significant difference in quality of blastocyst was observed. More precisely, in a group that was treated with MACS-ICSI, a higher percentage of good quality blastocysts was found among women older than 30 years (75.0 vs. 33.3%; P = 0.028), while there was no difference among younger women. If all included couples were compared regardless of age, no significant difference was observed in the outcome of the ICSI/MACS-ICSI cycles in terms of oocytes and embryos. Additionally, after the ICSI and MACS-ICSI procedures, the morphologies of the prepared spermatozoa were compared. Results showed that the overall percentage of morphologically normal spermatozoa did not differ significantly between the ICSI and MACS-ICSI procedures. However, detailed analyses of the morphologically abnormal spermatozoa revealed significantly more spermatozoa with abnormal tails after MACS-ICSI procedure, which may be potential consequence of the selection procedure. Moreover, the trends towards less spermatozoa with abnormal heads and towards more spermatozoa with abnormal necks and midpieces after MACS-ICSI procedure were revealed, although the differences were not significant.

CONCLUSIONS

Couples dealing with male infertility due to teratozoospermia can benefit from MACS selection of spermatozoa with higher percentage of good quality blastocysts but only when the woman is older than 30 years.

Clinical assessment of the male fertility

The evaluation of infertility in males consists of physical examination and semen analyses. Standardized semen analyses depend on the descriptive analysis of sperm motility, morphology, and concentration, with a threshold level that must be surpassed to be considered a fertile spermatozoon. Nonetheless, these conventional parameters are not satisfactory for clinicians since 25% of infertility cases worldwide remain unexplained. Therefore, newer tests methods have been established to investigate sperm physiology and functions by monitoring characteristics such as motility, capacitation, the acrosome reaction, reactive oxygen species, sperm DNA damage, chromatin structure, zona pellucida binding, and sperm-oocyte fusion. After the introduction of intracytoplasmic sperm injection technique, sperm maturity, morphology, and aneuploidy conditions have gotten more attention for investigating unexplained male infertility. In the present article, recent advancements in research regarding the utilization of male fertility prediction tests and their role and accuracy are reviewed.

Sperm morphological normality under high magnification is correlated to male infertility and predicts embryo development

Human sperm morphology has been described as an essential parameter for the diagnosis of male infertility and a prognostic indicator of natural or assisted pregnancies. Nevertheless, standard morphological assessment remains a subjective analysis and its impact on intracytoplasmic sperm injection (ICSI) is also of limited value. The objective of this prospective cohort study was to investigate whether motile sperm organelle morphology examination (MSOME) can improve semen analysis by better defining male infertility and providing a better prognosis for ICSI up to a year later. Data were obtained from 483 patients undergoing conventional semen analysis from June 2015 to June 2017 in a private university-affiliated in vitro fertilization (IVF) center. The correlation of MSOME with seminal parameters was evaluated. One hundred and thirty patients underwent ICSI up to a year later, and the correlation between MSOME and ICSI outcomes was established. Except for volume, all seminal parameters were positively correlated with MSOME I+II. MSOME was also distinct between World Health Organization (WHO) classification groups, with normozoospermic and oligoasthenoteratozoospermic presenting the higher and the lower proportion of MSOME I+II, respectively. MSOME I+II was prognostic for fertilization rate, high-quality cleavage-stage embryos rate, and blastocyst rate. The normality cutoff value based on blastocyst rate was MSOME I+II≥ 5.5%. MSOME could be a useful tool for the diagnosis of infertility severity as it is correlated with sperm morphology, motility, and concentration. Men who had higher MSOME I+II had better ICSI outcomes. The future use of MSOME as a routine method for semen analysis may be a reliable form of assessing male infertility.

Intracytoplasmic morphologically selected sperm injection and congenital birth defects: a retrospective cohort study

Our objective was to study the birth defect rates in intracytoplasmic morphologically selected sperm injection (IMSI) pregnancies. A cohort of couples presenting male factor infertility between January 2006 and January 2014 was retrospectively analyzed. Discharge letters and a telephone interview were performed for assessing pregnancy outcome. All clinical data were reviewed by a board certified medical geneticist. Main outcomes were fetal/birth defect and chromosomal abnormality rates. Two thousand two hundred and fifty-eight pregnancies were available for analysis, of them, 1669 (73.9%) resulting from ICSI and 2258 (26.1%) achieved by IMSI. Pregnancy outcome distribution did not show a significant difference. For the fresh embryo transfer cohort, fetal/birth defect rate was 4.5%, chromosomal aberration rate was 1.0%, and structural malformation rate was 3.5%. IMSI vs. ICSI pregnancies were less likely to involve a fetal/birth defect: 3.5% vs. 4.8%, respectively, but did not reach a statistical significance OR 0.71 (95% CI 0.39-1.22). Split by multiplicity, this trend existed only for singleton pregnancies; 1.4% structural malformations rate vs. 3.8%, respectively, OR 0.35 (95% CI 0.11-0.9). The frozen cohort demonstrated a significantly lower birth defect rate (OR 0.25, 95% CI 0.09-0.58). We conclude that IMSI procedure does not involve an increased malformation rate and may offer a reduced anomaly incidence. Further studies are required.

Is Varicocelectomy Useful for Subfertile Men with Isolated Teratozoospermia?

OBJECTIVE

To evaluate the effect of microsurgical varicocelectomy on sperm morphology in subfertile men with isolated teratozoospermia and a clinically palpable varicocele.

MATERIALS AND METHODS

A retrospective review was performed of men with isolated teratozoospermia who had undergone microsurgical varicocelectomy. Semen analyses following varicocelectomy were performed at 2- to 3-month intervals. Responders to the varicocelectomy were defined as those who fulfilled the following criteria in semen analysis: (1) an improvement in percentage of normal forms to ≥4% and (2) normal results for all other semen parameters.

RESULTS

A total of 80 patients underwent unilateral varicocelectomy (n = 49) or bilateral varicocelectomy (n = 31) (mean age of 36 ± 0.4 years, range 24-44). After a mean postoperative follow-up period of 6.8 months, the mean percentage of normal sperm forms increased from 0.9% to 3.5% (P < .001), and the mean sperm motility improved from 50.5% to 56.6% (P = .004). The number of responders to the surgery was 16 (20%), and their mean percentage of normal forms increased from 1.3% to 9.1%. The mean preoperative and postoperative semen volume and sperm concentration were not different (P > .05). No differences were observed in age, current smoking status, body mass index, or grade of varicocele between responders and nonresponders.

CONCLUSION

Varicocelectomy might be an option for treating subfertile patients with isolated teratozoospermia and a clinically apparent varicocele. However, patients should be advised that the surgery helps in limited patients only because more patients did not benefit from the surgery.

Intracytoplasmic morphologically selected sperm injection versus conventional intracytoplasmic sperm injection: a randomized controlled trial

BACKGROUND

Intracytoplasmic morphologically selected sperm injection (IMSI) is still proposed and employed in the clinical practice to improve the reproductive outcome in infertile couples scheduled for conventional intracytoplasmic sperm injection (cICSI). The aim of the current randomized controlled trial (RCT) was to test the hypothesis that IMSI gives a better live birth delivery rate than cICSI.

METHODS

Infertile couples scheduled for their first cICSI cycle for male factor were allocated using a simple randomization procedure. All available biological and clinical data were recorded and analyzed in a triple-blind fashion.

RESULTS

Our final analysis involved the first 121 patients (48 and 73 subjects for IMSI and cICSI arm, respectively) because the trial was stopped prematurely on the advice of the data safety and monitoring Committee because of concerns about IMSI efficacy at the first interim analysis. No significant difference between arms was detected in rates of clinical pregnancy per embryo transferred [11/34 (32.3%) vs. 15/64 (23.4%); odds ratio (OR) 1.56, 95% (confidence interval) CI 0.62-3.93, P = 0.343] and of live birth delivery [9/48 (18.8%) vs. 11/73 (15.1%); OR 1.30, 95%CI 0.49-3.42, P = 0.594).

CONCLUSION

Current data did not support the routine use of IMSI in the clinical practice for improving cICSI results in unselected infertile couples with male factor.

Poor-responder patients do not benefit from intracytoplasmic morphologically selected sperm injection

PURPOSE

To compare the outcomes of ICSI and IMSI in women presenting with poor ovarian response.

METHODS

Data of IMSI cycles performed from January 2011 to December 2013 were included in this retrospective cohort study. Patients were divided into two groups: normoresponder patients (NR group; patients with > 4 oocytes retrieved) and poor-responder patients (PR group; patients with ≤ 4 oocytes retrieved). Patients who underwent IMSI were matched with patients who underwent ICSI in the same period. The ICSI and IMSI outcomes were compared in the NR and PR groups.

RESULTS

A total of 414 matched cycles were included in this study. The NR group comprised 324 cycles (164 ICSI and 160 IMSI cycles), and the PR group comprised 90 cycles (43 ICSI and 47 IMSI cycles). In the NR group, no significant differences were observed between the ICSI- and IMSI-treated couples regarding cycle outcomes. In the PR group, fertilisation rate was significantly lower in IMSI-treated couples (53.9% ± 36.7% vs. 79.8% ± 29.3%). The proportion of cycles with embryo transfer (57.4 vs. 79.1%) and the number of transferred embryos (1.5 ± 0.8 vs. 1.9 ± 0.7) were significantly lower in IMSI compared with ICSI. Implantation, pregnancy and miscarriage rates were similar when ICSI or IMSI were performed.

CONCLUSIONS

Our results suggest that unselected couples undergoing ICSI that present with poor ovarian response to controlled ovarian stimulation do not benefit from sperm selection under high magnification prior to ICSI.