Intracytoplasmic sperm injection: state of the art in humans

High rate of detected variants in male PLCZ1 and ACTL7A genes causing failed fertilization after ICSI

STUDY QUESTION

What is the frequency of PLCZ1, ACTL7A, and ACTL9 variants in male patients showing fertilization failure after ICSI, and how effective is assisted oocyte activation (AOA) for them?

SUMMARY ANSWER

Male patients with fertilization failure after ICSI manifest variants in PLCZ1 (29.09%), ACTL7A (14.81%), and ACTL9 (3.70%), which can be efficiently overcome by AOA treatment with ionomycin.

WHAT IS KNOWN ALREADY

Genetic variants in PLCZ1, and more recently, in ACTL7A, and ACTL9 male genes, have been associated with total fertilization failure or low fertilization after ICSI. A larger patient cohort is required to understand the frequency at which these variants occur, and to assess their effect on the calcium ion (Ca2+) release during oocyte activation. AOA, using ionomycin, can restore fertilization and pregnancy rates in patients with PLCZ1 variants, but it remains unknown how efficient this is for patients with ACTL7A and ACTL9 variants.

STUDY DESIGN SIZE DURATION

This prospective study involved two patient cohorts. In the first setting, group 1 (N = 28, 2006-2020) underwent only PLCZ1 genetic screening, while group 2 (N = 27, 2020-2023) underwent PLCZ1, ACTL7A, and ACTL9 genetic screening. Patients were only recruited when they had a mean fertilization rate of ≤33.33% in at least one ICSI cycle with at least four MII oocytes. Patients underwent a mouse oocyte activation test (MOAT) and at least one ICSI-AOA cycle using calcium chloride (CaCl2) injection and double ionomycin exposure at our centre. All patients donated a saliva sample for genetic screening and a sperm sample for further diagnostic tests, including Ca2+ imaging.

PARTICIPANTS/MATERIALS SETTING METHODS

Genetic screening was performed via targeted next-generation sequencing. Identified variants were classified by applying the revised ACMG guidelines into a Bayesian framework and were confirmed by bidirectional Sanger sequencing. If variants of uncertain significance or likely pathogenic or pathogenic variants were found, patients underwent additional determination of the sperm Ca2+-releasing pattern in mouse (MOCA) and in IVM human (HOCA) oocytes. Additionally, ACTL7A immunofluorescence and acrosome ultrastructure analyses by transmission electron microscopy (TEM) were performed for patients with ACTL7A and/or ACTL9 variants.

MAIN RESULTS AND THE ROLE OF CHANCE

Overall, the frequency rate of PLCZ1 variants was 29.09%. Moreover, 14.81% of patients carried ACTL7A variants and 3.70% carried ACTL9 variants. Seven different PLCZ1 variants were identified (p.Ile74Thr, p.Gln94*, p.Arg141His, p.His233Leu, p.Lys322*, p.Ile379Thr, and p.Ser500Leu), five of which are novel. Interestingly, PLCZ1 variants p.Ser500Leu and p.His233Leu occurred in 14.55% and 9.09% of cases. Five different variants were found in ACTL7A (p.Tyr183His, p.Gly214Ser, p.Val340Met, p.Ser364Glnfs*9, p.Arg373Cys), four of them being identified for the first time. A novel variant in ACTL9 (p.Arg271Pro) was also described. Notably, both heterozygous and homozygous variants were identified.The MOCA and HOCA tests revealed abnormal or absent Ca2+ release during fertilization in all except one patient, including patients with PLCZ1 heterozygous variants. TEM analysis revealed abnormal acrosome ultrastructure in three patients with ACTL7A variants, but only patients with homozygous ACTL7A variants showed reduced fluorescence intensity in comparison to the control.AOA treatment significantly increased the fertilization rate in the 19 patients with detected variants (from 11.24% after conventional ICSI to 61.80% after ICSI-AOA), as well as positive hCG rate (from 10.64% to 60.00%) and live birth rate (from 6.38% to 37.14%), resulting in 13 healthy newborns. In particular, four live births and two ongoing pregnancies were produced using sperm from patients with ACTL7A variants.

LIMITATIONS REASONS FOR CAUTION

Genetic screening included exonic and outflanking intronic regions, which implies that deep intronic variants were missed. In addition, other male genes or possible female-related factors affecting the fertilization process remain to be investigated.

WIDER IMPLICATIONS OF THE FINDINGS

Genetic screening of PLCZ1, ACTL7A, and ACTL9 offers a fast, cost-efficient, and easily implementable diagnostic test for total fertilization failure or low fertilization after ICSI, eliminating the need for complex diagnostic tests like MOAT or Ca2+ analysis. Nonetheless, HOCA remains the most sensitive functional test to reveal causality of uncertain significance variants. Interestingly, heterozygous PLCZ1 variants are sufficient to cause inadequate Ca2+ release during ICSI. Most importantly, AOA treatment using CaCl2 injection followed by double ionomycin exposure is highly effective for this patient group, including those with ACTL7A variants, who also display a Ca2+-release deficiency.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by the Flemish Fund for Scientific Research (FWO) (TBM-project grant T002223N awarded to B.H.) and by the Special Research Fund (BOF) (starting grant BOF.STG.2021.0042.01 awarded to B.H.). A.C.B., R.R.G., C.C., E.V.D.V., A.R., D.S., L.L., P.C., S.S., A.B., and F.V.M. have nothing to disclose. B.H. reports a research grant from FWO and BOF, and reports being a board member of the Belgian Ethical Committee on embryo research.

TRIAL REGISTRATION NUMBER

N/A.

The relationship between cardiometabolic index and infertility in American adults: a population-based study

Background

Infertility is a fertility disorder caused by various factors, with lipid metabolism playing a crucial role in its development. The cardiometabolic index (CMI), which combines blood lipids (TG/HDL-C) and obesity-related parameters (WHtR), is a new quantitative indicator. This study used NHANES data to investigate the relationship between CMI and the incidence of infertility.

Methods

We utilized data from women who took part in the National Health and Nutrition Examination Survey (NHANES) from 2015 to March 2020 to calculate the CMI index. Subsequently, we used multivariate logistic regression, smooth curve fitting, and subgroup analysis to investigate the relationship between the CMI index and infertility.

Results

The logistic regression model revealed a significant positive correlation between the CMI index and infertility, even after adjusting for all confounding variables (OR=3.23, 95%CI: 1.55-6.73, p=0.0017). This association remained consistent across all subgroups (p>0.05 for all interactions). Smooth curve fitting demonstrated a positive nonlinear relationship between CMI and infertility. However, the CMI index had limited diagnostic power for infertility (AUC=0.60, 95%CI: 0.56-0.65). However, the CMI-BMI index combined with BMI had good predictive performance (AUC=0.722, 95%CI: 0.676-0.767).

Conclusion

The CMI index shows a positive correlation with infertility, but its diagnostic value is restricted. The combination with BMI has good diagnostic value. Further investigation is required to determine the effectiveness of the CMI index as an early indicator of infertility.

Association Between Triglyceride Glucose Index and Infertility in Reproductive-Aged Women: A Cross-Sectional Study

Purpose

In recent years, female infertility has become a research hotspot in the field of health management, and its cause may be related to insulin resistance (IR). We used a novel and practical IR indicator, the TyG index to explore its association with infertility.

Patients and Methods

We calculated the TyG index using data from adult women who participated in the National Health and Nutrition Examination Survey (NHANES) from 2013 to 2018. Then, we used multivariate logistic regression, smooth curve fitting, and subgroup analysis to examine the association between the TyG index and infertility in women.

Results

Logistic regression models showed a positive correlation between the TyG index and infertility, which remained significant even after adjusting for all confounders (OR=1.51,95% CI:1.14-2.00, p=0.005). This association was consistent in all subgroups (age, education level, marital status, BMI, smoking, alcohol consumption, hypertension, diabetes, pelvic inflammatory disease/PID treatment, and menstrual regularity in the past 12 months) (p>0.05 for all interactions). However, the diagnostic power of the TyG index for infertility was limited (AUC=0.56, 95% CI: 0.52-0.61).

Conclusion

The TyG index is positively correlated with infertility, but its diagnostic value is limited. Further research is needed on the TyG index as an early predictor of infertility.

Qualified sperm selection based on the rheotaxis and thigmotaxis in a microfluidic system

Microfluidic systems with the ability to mimic the female reproductive tract (FRT) and sperm features have emerged as promising methods to separate sperm with higher quality for the assistant reproductive technology. Thereby, we designed and fabricated a microfluidic system based on FRT features with a focus on rheotaxis and thigmotaxis for passive sperm separation. In this regard, four various geometries (linear, square, zigzag, and sinusoidal) were designed, and the effect of rheotaxis and thigmotaxis were investigated. Although separated sperm in all microchannels were 100% motile, non-linear geometries were more effective than linear geometry in the term of separating the progressive sperm with high quality. In the presence of upstream flow, periodical changes in the slope of walls (in non-linear geometries) give rise to the periodical facing sperm with a high flow rate in the middle of microchannels, which was a reason for the high quality of separated sperm. However, because of sharp corners in the square and zigzag microchannels that create dead zones with a lack of upstream flow, which is noticeable via simulation results, these geometries have obstacles against sperm swimming toward the outlet, which was proved by image analysis. The sinusoidal geometry showed the highest enhancement level of the designed geometries compared to the linear geometry. Separated sperm exhibited 34.7% normal morphology, 100% motility, and 100% viability in the sinusoidal geometry. Therefore, the periodic change in the position of sperm from one wall to another wall can be a strategy for separating sperm with high quality.

Graphical abstract

In the present study, we used a microfluidic system for studying the combined effects of thigmotaxis and rheotaxis for sperm separation process to achieve the successful Assisted reproductive technology (ART). The designed PDMS-based microfluidic system had four various geometries, including linear, square, zigzag, and sinusoidal. The functionality of separated sperm was evaluated by sperm tracking (ImageJ), motility assay (CASA software), and morphology assay (Papanicolaou ultrafast staining). Probing various geometries revealed 100% motility. In non-linear geometries, sperm's periodic detachment from the walls gave rise to the periodic interaction with the high flow velocity in the center of the channel, resulting in the separation of high-quality sperm with progressive motility. The collected data proved the influence of thigmotaxis on the quality of separated sperm. Morphologically improvement in separated sperm from the sinusoidal geometry was significant than others, which means the sinusoidal structure would be the best candidate for the sperm separation process.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13534-023-00294-8.

From Diagnosis to Treatment: Comprehensive Care by Reproductive Urologists in Assisted Reproductive Technology

Infertility is a global health concern, with male factors playing an especially large role. Unfortunately, however, the contributions made by reproductive urologists in managing male infertility under assisted reproductive technology (ART) often go undervalued. This narrative review highlights the important role played by reproductive urologists in diagnosing and treating male infertility as well as any barriers they face when providing services. This manuscript presents a comprehensive review of reproductive urologists' role in managing male infertility, outlining their expertise in diagnosing and managing male infertility as well as reversible causes and performing surgical techniques such as sperm retrieval. This manuscript investigates the barriers limiting urologist involvement such as limited availability, awareness among healthcare professionals, and financial constraints. This study highlights a decrease in male fertility due to lifestyle factors like sedentary behavior, obesity, and substance abuse. It stresses the significance of conducting an evaluation process involving both male and female partners to identify any underlying factors contributing to infertility and to identify patients who do not require any interventions beyond ART. We conclude that engaging urologists more effectively in infertility management is key to optimizing fertility outcomes among couples undergoing assisted reproductive technology treatments and requires greater education among healthcare providers regarding the role urologists and lifestyle factors that could have an effect on male fertility.

Intelligence, motoric and psychological outcomes in children from different ART treatments: a systematic review and meta-analysis

BACKGROUND

Subtle abnormalities in children's intelligence, motor skills, and psychology from various assisted reproductive treatments (ARTs) might be underdiagnosed. Understanding the prognosis of intelligence, motor skills, and psychology in children from ART would provide parents with reasonable expectations and enable them to plan relevant support to achieve the optimum potential in ART children.

METHODS

We searched PubMed, EMBASE, Ovid, Google Scholar, and Scopus databases until April 13, 2021, to identify relevant studies. Thirty-four studies met the inclusion and exclusion criteria. The meta-analysis employed a standardized mean difference model. The outcome of this study is to compare intelligence quotient (IQ), motoric ability, and behavioral problems between all ARTs, in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI) to naturally conceived (NC) children. Subdomains of intelligence based on the Cattell, Horn, and Carroll Model (CHC Model) of cognitive architecture, including fluid reasoning, short-term and working memory, processing speed, visual-spatial ability, long-term memory retrieval, and crystalized intelligence (knowledge), were evaluated and summarized in details. Motor skill was stratified into two domains: gross motoric and fine motoric. Behavioral problem was categorized as externalizing and internalizing behavior.

RESULTS

Meta-analysis showed that verbal intelligence score in IVF toddlers is significantly lower than NC toddlers (p = 0.02); conversely, ICSI toddlers scored significantly higher verbal intelligence score compared to NC toddlers (p = 0.005). Toddlers born after ART had significantly lower non-verbal intelligence score (p = 0.047). IVF toddlers scored significantly lower fine motor score (p = 0.01) compared to naturally conceived toddlers. Based on parent's CBCL, NC toddlers had higher total (p = 0.01) and externalizing behavior (p = 0.001) scores  compared to ART toddlers. Evaluation of full scale IQ and all domains of intelligence in preschool and primary school children revealed that no significant differences exist between ART and NC children. Based on preschool and primary school parents' CBCL, IVF children had significantly lower externalizing behavior score compared to NC children (p = 0.04). Meta-analyses of studies on young adolescents revealed that ART young adolescents scored higher academically than their NC counterparts, including on mathematics (p < 0.00001) and reading or language (p < 0.00001).

CONCLUSIONS

Despite differences in certain aspects, this finding suggests that ART is unlikely to cause negative impacts on children's neurodevelopment.

Significant differences in efficiency between two commonly used ionophore solutions for assisted oocyte activation (AOA): a prospective comparison of ionomycin and A23187

PURPOSE

Despite the success of ICSI in treating severe male factor infertile patients, total fertilization failure (FF) still occurs in around 1-3% of ICSI cycles. To overcome FF, the use of calcium ionophores has been proposed to induce oocyte activation and restore fertilization rates. However, assisted oocyte activation (AOA) protocols and ionophores vary between laboratories, and the morphokinetic development underlying AOA remains understudied.

METHODS

A prospective single-center cohort study involving 81 in vitro matured metaphase-II oocytes from 66 oocyte donation cycles artificially activated by A23187 (GM508 CultActive, Gynemed) (n=42) or ionomycin (n=39). Parthenogenesis was induced, and morphokinetic parameters (tPNa, tPNf, t2-t8, tSB, and tB) were compared between the 2 study groups and a control group comprising 39 2PN-zygotes from standard ICSI cycles.

RESULTS

Ionomycin treatment resulted in higher activation rates compared to A23187 (38.5% vs 23.8%, p=0.15). Importantly, none of the A23187-activated parthenotes formed blastocysts. When evaluating the morphokinetic dynamics between the two ionophores, we found that tPNa and tPNf were significantly delayed in the group treated by A23187 (11.84 vs 5.31, p=0.002 and 50.15 vs 29.69, p=0.005, respectively). t2 was significantly delayed in A23187-activated parthenotes when compared to the double heterologous control embryo group. In contrast, the morphokinetic development of ionomycin-activated parthenotes was comparable to control embryos (p>0.05).

CONCLUSION

Our results suggest that A23187 leads to lower oocyte activation rates and profoundly affects morphokinetic timings and preimplantation development in parthenotes. Despite our limited sample size and low parthenote competence, standardization and further optimization of AOA protocols may allow wider use and improved outcomes for FF cycles.

Assisted Reproduction and Discussion of Rare Cases in Monozygotic Twinning

Assisted reproductive technology is a crucial factor that increases the incidence of monozygotic twinning in humans. This article discusses the impact of various indicators in assisted reproductive technology studies on pregnancy outcomes, especially studies with a large number of clinical cases. Furthermore, three rare cases in multiples pregnancy are discussed: fetus papyraceous of a pair of male monozygotic twins in a set of triplets, two pairs of sesquizygotic twins with sex-discordance, and rare conjoined triplets.

Assisted gamete treatment to pinpoint acquired meiotic maturity and overcome oocyte activation deficiency contributed by both gametes

Objective

To treat couples with total fertilization failure (TFF) based on a combined oocyte- and sperm-related oocyte activation deficiency by optimizing oocyte response to chemical activation with calcium ionophore.

Design

Case report.

Setting

Tertiary Hospital.

Patients

Two couples with a history of TFF after intracytoplasmic sperm injection intracytoplasmic sperm injection (ICSI).

Interventions

To overcome oocyte-related oocyte activation deficiency (OAD), extended in vivo/in vitro oocyte maturation was performed to enhance ooplasmic maturity; to address sperm-related OAD, assisted gamete treatment (AGT) was performed to trigger oocyte activation.

Main outcome measures

Treatment cycle outcomes for the 2 couples undergoing ICSI with extended oocyte maturation (EOM) and AGT.

Results

We identified 2 couples with TFF after ICSI because of a combined factor of OAD confirmed by phospholipase C zeta expression and genomic assessment. Initial AGT treatment alone failed to enhance fertilization, suggesting superimposed oocyte dysmaturity prohibiting oocytes from responding to chemical stimuli. To address this complex form of OAD, in couple 1, 27 oocytes out of 34 retrieved presented normal metaphase II spindles after EOM; ICSI with AGT yielded a fertilization rate of 63.0% (17/27). All 17 zygotes were cryopreserved initially. Two embryos were thawed and transferred, yielding a monochorionic diamniotic twin pregnancy. Couple 2 underwent 3 ICSI cycles with EOM and AGT; 91.4% (32/35) of oocytes displayed normal metaphase II spindle and achieved an overall fertilization rate of 43.8% (14/32). A total of 12 blastocysts were cryopreserved. A single 46XY blastocyst was thawed and transferred, resulting in a singleton pregnancy.

Conclusions

Our study has demonstrated the usefulness of EOM by targeting spindle presence to enhance chemical responses to AGT.

What Does Intracytoplasmic Sperm Injection Change in Embryonic Development? The Spermatozoon Contribution

The intracytoplasmic sperm injection (ICSI) technique was invented to solve severe male infertility due to altered sperm parameters. Nowadays, it is applied worldwide for the treatment of couple infertility. ICSI is performed with any available spermatozoon from surgery or ejaculated samples, whatever are the sperm motility, morphology or quantity. The aim of the present review was to study if embryo development and kinetics would be modified by (1) ICSI under the technical aspects, (2) the micro-injected spermatozoa in connection with male infertility. From published data, it can be seen that ICSI anticipates the zygote kinetics Furthermore, because fertilization rate is higher in ICSI compared to conventional in vitro fertilization (IVF), more blastocysts are obtained for clinical use in ICSI. Sperm and spermatozoa characteristics, such as sperm parameters, morphology and vitality, DNA content (levels of sperm DNA fragmentation, microdeletions, and chromosomal abnormalities), RNA content, epigenetics, and sperm recovery site (testicular, epididymis, and ejaculated), have an impact on fertilization and blastocyst rates and embryo kinetics in different ways. Even though ICSI is the most common solution to solve couples' infertility, the causes of male infertility are crucial in building a competent spermatozoa that will contribute to normal embryonic development and healthy offspring.

Female Infertility Is Associated with an Altered Expression Profile of Different Members of the Tachykinin Family in Human Granulosa Cells

Neurokinin B (NKB) and its cognate receptor, NK3R, play a key role in the regulation of reproduction. NKB belongs to the family of tachykinins, which also includes substance P and neurokinin A, both encoded by the by the gene TAC1, and hemokinin-1, encoded by the TAC4 gene. In addition to NK3R, tachykinin effects are mediated by NK1R and NK2R, encoded by the genes TACR1 and TACR2, respectively. The role of these other tachykinins and receptors in the regulation of women infertility is mainly unknown. We have analyzed the expression profile of TAC1, TAC4, TACR1, and TACR2 in mural granulosa and cumulus cells from women presenting different infertility etiologies, including polycystic ovarian syndrome, advanced maternal age, low ovarian response, and endometriosis. We also studied the expression of MME, the gene encoding neprilysin, the most important enzyme involved in tachykinin degradation. Our data show that TAC1, TAC4, TACR1, TACR2, and MME expression is dysregulated in a different manner depending on the etiology of women infertility. The abnormal expression of these tachykinins and their receptors might be involved in the decreased fertility of these patients, offering a new insight regarding the diagnosis and treatment of women infertility.

Intracytoplasmic sperm injection in sturgeon species: A promising reproductive technology of selected genitors

Sturgeons are the most endangered species group and their wild populations continue to decrease. In this study, we apply intracytoplasmic sperm injection (ICSI), an assisted reproductive technology, for the first time in endangered and critically endangered sturgeons. Using various egg-sperm species combinations we performed different ICSI experiments with immobilized pre- or non-activated spermatozoa, single or many, fresh or cryopreserved. Then we evaluated the fertilization success as well as the paternity of the resultant embryos and larvae. Surprisingly, all experimental groups exhibited embryonic development. Normal-shaped feeding larvae produced in all egg-sperm species-combination groups after ICSI using single fresh-stripped non-activated spermatozoa, in one group after ICSI using single fresh-stripped pre-activated spermatozoa, and in one group after ICSI using multiple fresh-stripped spermatozoa. ICSI with single cryopreserved non-activated spermatozoa produced neurula stage embryos. Molecular analysis showed genome integration of both egg- and sperm-donor species in most of the ICSI transplants. Overall, ICSI technology could be used as an assisted reproduction technique for producing sturgeons to rescue valuable paternal genomes.

Past, present and future of ICSI in livestock species

During the past 2 decades, intracytoplasmic sperm injection (ICSI) has become a routine technique for clinical applications in humans. The widespread use among domestic species, however, has been limited to horses. In horses, ICSI is used to reproduce elite individuals and, as well as in humans, to mitigate or even circumvent reproductive barriers. Failures in superovulation and conventional in vitro fertilization (IVF) have been the main reason for the use of this technology in horses. In pigs, ICSI has been successfully used to produce transgenic animals. A series of factors have resulted in implementation of ICSI in pigs: need to use zygotes for numerous technologies, complexity of collecting zygotes surgically, and problems of polyspermy when there is utilization of IVF procedures. Nevertheless, there have been very few additional reports confirming positive results with the use of ICSI in pigs. The ICSI procedure could be important for use in cattle of high genetic value by maximizing semen utilization, as well as for utilization of spermatozoa from prepubertal bulls, by providing the opportunity to shorten the generation interval. When attempting to utilize ICSI in ruminants, there are some biological limitations that need to be overcome if this procedure is going to be efficacious for making genetic improvements in livestock in the future. In this review article, there is an overview and projection of the methodologies and applications that are envisioned for ICSI utilization in these species in the future.

V, Joseph D, Meitei HY, Asampille G, Kumar P, Gowda G. A. N, Kalthur G, Kovacic B, Adiga SK. ICSI in non-male factor infertility patients does not alter metabolomic signature in sibling embryos as evidenced by sensitivity enhanced nuclear magnetic resonance (NMR) spectroscopy

Intracytoplasmic sperm injection (ICSI) was developed to overcome male factor infertility, however, there recently has been an increasing trend in ICSI usage irrespective of the etiology, demonstrating an overuse of this insemination technique. There is a limited knowledge on the behaviour of ICSI derived embryos in non-male factor infertility patients. Metabolomic assessment of preimplantation embryos in conjunction with morphological evaluation can provide better understanding of embryonic behaviour. Hence, this study was undertaken to explore if there are any metabolomic differences between IVF and ICSI derived sibling day-5 blastocysts from non-male factor infertility patients. This prospective study included nineteen couples with non-male factor infertility undergoing Assisted Reproductive Technology. The sibling oocytes retrieved from each patient were randomly assigned to two groups and inseminated either by IVF or ICSI. Spent culture media (SCM) in which embryos were cultured up to day 5 were collected and investigated using sensitivity enhanced NMR based metabolite profiling utilizing high resolution (800 MHz) NMR equipped with cryogenically cooled micro-coil (1.7 mm) probe. The metabolomic signature between IVF and ICSI derived sibling blastocysts was assessed. A significant reduction in the concentrations of pyruvate, citrate, glucose and lysine were observed in both IVF and ICSI sibling embryos compared to medium control (P< 0.05-0.001). Further, histidine and valine level was found lower in ICSI embryos compared to medium control (P<0.05) during 96 hours of in vitro culture. Notably, between IVF and ICSI SCM, no significant difference in the concentration of the metabolites was found. Our results suggest that ICSI in non-male factor does not alter the SCM metabolomic signature during 96 hours of embryonic development.

Evaluation of sperm integrin α5β1 as a potential marker of fertility in humans

Sperm selection for assisted reproduction techniques is generally based on basic parameters, while key aspects of sperm competence and its journey from the deposition site to the fertilization site are overlooked. Consequently, identifying molecular markers in spermatozoa that can efficiently predict the fertility of a semen sample could be of great interest, particularly in cases of idiopathic male infertility. When spermatozoa reach the female reproductive tract, it provides to them the cellular and molecular microenvironment needed to acquire fertilizing ability. In this sense, considering the role that integrin α5β1 of spermatozoa plays in reproduction-related events, we investigated the correlation between the subcellular localization of sperm integrin α5β1 and early embryo development outcome after in vitro fertilization (IVF) procedures in human. Twenty-four semen samples from normozoospermic men and metaphase II (MII) oocytes from healthy women aged under 38 years, from couples who underwent IVF cycles, were used in this work. Sperm α5β1 localization was evaluated by immunofluorescence assay using an antibody against integrin α5 subunit. Integrin α5β1 was mainly localized in the sperm acrosomal region (45.33±7.89%) or the equatorial segment (30.12±7.43%). The early embryo development rate (data obtained from the Fertility Center) correlated positively with the localization of α5β1 in the acrosomal region (number of usable embryos / inseminated oocytes: ρ = 0.75; p<0.01 and number of usable embryos/total number of two pronuclear zygotes: ρ = 0.80; p<0.01). However, this correlation was not significant when the equatorial segment mark was evaluated. In addition, human sperm released from co-culture with bovine oviductal epithelial cells (BOEC) showed a significant enrichment in the acrosomal localization pattern of α5β1 compared to those sperm that were not co-cultured with BOEC (85.20±5.35% vs 35.00±17.09%, respectively, p<0.05). In conclusion, the evaluation of sperm integrin α5β1 immunolocalization could be a useful tool to select sperm with fertilizing ability from human semen samples before IVF procedures.

Comparison of sperm preparation methods to improve the recovery of mature spermatozoa in sub-fertile males

The integrity of chromatin in the spermatozoon is essential for reproductive outcome. The aim of this study was to evaluate the most effective and cost-effective method to reduce the percentage of spermatozoa with defects in chromatin decondensation for use in assisted reproductive technologies (ART) procedures. Sperm samples from 15 sub-fertile males were examined at CFA Naples to determine the sperm decondensation index (SDI), using the aniline blue test, before and after preparation, comparing density gradients with two different swim-up approaches. All three techniques led to a reduction in decondensed spermatozoa with no statistical difference (P > 0.05) between the control and the treated sperm. In contrast, we found a highly significant decrease in SDI (P < 0.01) after the two swim-up methods in all the samples, confirming the efficacy of these methods in lowering the percentage of chromatin compaction damage. There was no statistical difference between the two swim-up methods, however swim-up from the pellet led to improved count, motility and the percentage of normal condensed spermatozoa. We suggest that swim-up from the pellet be used in ART on sub-fertile males, both to reduce cell stress by multiple centrifugation and improve the recovery rate of mature spermatozoa.

Dairy Product Consumption and Oligo-Astheno-Teratozoospermia Risk: A Hospital-Based Case-Control Study in China

Background: Researches on the association of dairy products consumption with Oligo-astheno-teratozoospermia (OAT) risk has been limited and controversial. Therefore, we aim to explore the aforementioned association among Chinese men.

Methods: A hospital-based case-control study was conducted in men consisting of 106 cases of OAT and 581 controls. Intakes of dairy products and their related nutrients were collected using a semi-quantitative food frequency questionnaire and semen quality was analyzed according to the World Health Organization guidelines. The daily intake of dairy products and their related nutrients was categorized into three groups with the lowest tertile serving as the reference category. Odds ratios (ORs) and 95% confidence intervals (CIs) of association between dairy intake and OTA risk were calculated by the multivariable logistic regression models.

Results: No significant association was found between total dairy (OR _T3vs.T1 =1.53, 95% CI: 0.85–2.78), protein (OR _T3vs.T1 =1.51, 95% CI: 0.84–2.75), or calcium (OR _T3vs.T1 = 1.46, 95% CI: 0.81–2.66) and the OAT risk in the main findings. However, we observed a statistically significant positive association of dairy fat intake with OAT risk (OR _T3vs.T1 =1.93, 95% CI: 1.06–3.58). The findings were consistent with the main results when we carried out subgroup analysis stratified by body mass index.

Conclusion: A significant positive association was found between dairy fat intake and the risk of OAT. Further large-scale prospective studies are required to confirm this finding.

OUP accepted manuscript

BACKGROUND

Oocyte activation deficiency (OAD) is attributed to the majority of cases underlying failure of ICSI cycles, the standard treatment for male factor infertility. Oocyte activation encompasses a series of concerted events, triggered by sperm-specific phospholipase C zeta (PLCζ), which elicits increases in free cytoplasmic calcium (Ca²⁺) in spatially and temporally specific oscillations. Defects in this specific pattern of Ca²⁺ release are directly attributable to most cases of OAD. Ca²⁺ release can be clinically mediated via assisted oocyte activation (AOA), a combination of mechanical, electrical and/or chemical stimuli which artificially promote an increase in the levels of intra-cytoplasmic Ca²⁺. However, concerns regarding safety and efficacy underlie potential risks that must be addressed before such methods can be safely widely used.

OBJECTIVE AND RATIONALE

Recent advances in current AOA techniques warrant a review of the safety and efficacy of these practices, to determine the extent to which AOA may be implemented in the clinic. Importantly, the primary challenges to obtaining data on the safety and efficacy of AOA must be determined. Such questions require urgent attention before widespread clinical utilization of such protocols can be advocated.

SEARCH METHODS

A literature review was performed using databases including PubMed, Web of Science, Medline, etc. using AOA, OAD, calcium ionophores, ICSI, PLCζ, oocyte activation, failed fertilization and fertilization failure as keywords. Relevant articles published until June 2019 were analysed and included in the review, with an emphasis on studies assessing large-scale efficacy and safety.

OUTCOMES

Contradictory studies on the safety and efficacy of AOA do not yet allow for the establishment of AOA as standard practice in the clinic. Heterogeneity in study methodology, inconsistent sample inclusion criteria, non-standardized outcome assessments, restricted sample size and animal model limitations render AOA strictly experimental. The main scientific concern impeding AOA utilization in the clinic is the non-physiological method of Ca²⁺ release mediated by most AOA agents, coupled with a lack of holistic understanding regarding the physiological mechanism(s) underlying Ca²⁺ release at oocyte activation.

LIMITATIONS, REASONS FOR CAUTION

The number of studies with clinical relevance using AOA remains significantly low. A much wider range of studies examining outcomes using multiple AOA agents are required.

WIDER IMPLICATIONS

In addition to addressing the five main challenges of studies assessing AOA safety and efficacy, more standardized, large-scale, multi-centre studies of AOA, as well as long-term follow-up studies of children born from AOA, would provide evidence for establishing AOA as a treatment for infertility. The delivery of an activating agent that can more accurately recapitulate physiological fertilization, such as recombinant PLCζ, is a promising prospect for the future of AOA. Further to PLCζ, many other avenues of physiological oocyte activation also require urgent investigation to assess other potential physiological avenues of AOA.

STUDY FUNDING/COMPETING INTERESTS

D.G. was supported by Stanford University’s Bing Overseas Study Program. J.K. was supported by a Healthcare Research Fellowship Award (HF-14-16) made by Health and Care Research Wales (HCRW), alongside a National Science, Technology, and Innovation plan (NSTIP) project grant (15-MED4186-20) awarded by the King Abdulaziz City for Science and Technology (KACST). The authors have no competing interests to declare.

Novel bi-allelic variants in ACTL7A are associated with male infertility and total fertilization failure

STUDY QUESTION

What are the genetic causes of total fertilization failure (TFF) in a proband suffering from male infertility?

SUMMARY ANSWER

Novel compound heterozygous variants (c.[463C>T];[1084G>A], p.[(Arg155Ter)];[(Gly362Arg)]) in actin-like protein 7A (ACTL7A) were identified as a causative genetic factor for human TFF.

WHAT IS KNOWN ALREADY

ACTL7A, an actin-related protein, is essential for spermatogenesis. ACTL7A variants have been reported to cause early embryonic arrest in humans but have not been studied in human TFF.

STUDY DESIGN, SIZE, DURATION

We recruited a non-consanguineous family whose son was affected by infertility characterized by TFF after ICSI. Whole-exome sequencing was used to identify the potential pathogenic variants. Artificial oocyte activation (AOA) after ICSI was performed to overcome TFF and any resulting pregnancy was followed up.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Sanger sequencing was performed to validate the variants. Pathogenicity of the identified variants was predicted by in silico tools. The ultrastructure of spermatozoa was studied by transmission electron microscopy (TEM). Immunofluorescence staining and western blotting were used to investigate the mechanism of the variants on the affected spermatozoa.

MAIN RESULTS AND THE ROLE OF CHANCE

Novel compound heterozygous variants in ACTL7A (c.[463C>T];[1084G>A], p.[(Arg155Ter)];[(Gly362Arg)]) were identified in a family with TFF after ICSI. In silico analysis predicted that the variants lead to a disease-causing protein. TEM showed that the ACTL7A variants caused ultrastructural defects in the acrosome and perinuclear theca. Protein expression of ACTL7A and phospholipase C zeta, a key sperm-borne oocyte activation factor, was significantly reduced in the affected sperm compared to healthy controls, suggesting that the ACLT7A variants lead to an oocyte activation deficiency and TFF. AOA by calcium ionophore (A23187) after ICSI successfully rescued the TFF and achieved a live birth for the patient with ACTL7A variants.

LIMITATIONS, REASONS FOR CAUTION

Given the rarity of sperm-associated TFF, only one family with an only child carrying the ACTL7A variants was found. In addition, the TFF phenotype was not assessed in two or more ICSI cycles, due to the intervention in ICSI with AOA after one failed ICSI cycle. Further studies should validate the ACTL7A variants and its effect on male infertility in larger independent cohorts.

WIDER IMPLICATIONS OF THE FINDINGS

: Our findings revealed a critical role of ACTL7A in male fertility and identified bi-allelic variants in ACTL7A associated with human TFF, which expands the genetic spectrum of TFF and supports the genetic diagnosis of TFF patients. We also rescued TFF by AOA and obtained a healthy live birth, which provides a potentially effective intervention for patients with ACTL7A pathogenic variants.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the National Natural Science Foundation of China (81971374 and 81401267). No conflicts of interest were declared.

TRIAL REGISTRATION NUMBER

N/A.

DNA methylation and gene expression changes in mouse pre- and post-implantation embryos generated by intracytoplasmic sperm injection with artificial oocyte activation

BACKGROUND

The application of artificial oocyte activation (AOA) after intracytoplasmic sperm injection (ICSI) is successful in mitigating fertilization failure problems in assisted reproductive technology (ART). Nevertheless, there is no relevant study to investigate whether AOA procedures increase developmental risk by disturbing subsequent gene expression at different embryonic development stages.

METHODS

We used a mouse model to explore the influence of AOA treatment on pre- and post-implantation events. Firstly, the developmental potential of embryos with or without AOA treatment were assessed by the rates of fertilization and blastocyst formation. Secondly, transcriptome high-throughput sequencing was performed among the three groups (ICSI, ICSI-AOA and dICSI-AOA groups). The hierarchical clustering and Principal Component Analysis (PCA) analysis were used. Subsequently, Igf2r/Airn methylation analysis were detected using methylation-specific PCR sequencing following bisulfite treatment. Finally, birth rate and birth weight were examined following mouse embryo transfer.

RESULTS

The rates of fertilization and blastocyst formation were significantly lower in oocyte activation-deficient sperm injection group (dICSI group) when compared with the ICSI group (30.8 % vs. 84.4 %, 10.0 % vs. 41.5 %). There were 133 differentially expressed genes (DEGs) between the ICSI-AOA group and ICSI group, and 266 DEGs between the dICSI-AOA group and ICSI group. In addition, the imprinted gene, Igf2r is up regulated in AOA treatment group compared to control group. The Igf2r/Airn imprinted expression model demonstrates that AOA treatment stimulates maternal allele-specific mehtylation spreads at differentially methylated region 2, followed by the initiation of paternal imprinted Airn long non-coding (lnc) RNA, resulting in the up regulated expression of Igf2r. Furthermore, the birth weight of newborn mice originating from AOA group was significantly lower compared to that of ICSI group. The pups born following AOA treatment did not show any other abnormalities during early development. All offspring mated successfully with fertile controls.

CONCLUSIONS

AOA treatment affects imprinted gene Igf2r expression and mehtylation states in mouse pre- and post-implantation embryo, which is regulated by the imprinted Airn. Nevertheless, no significant differences were found in post-natal growth of the pups in the present study. It is hoped that this study could provide valuable insights of AOA technology in assisted reproduction biology.

Testicular sperm characteristics in men with nonobstructive azoospermia and their impact on intracytoplasmic sperm injection outcome

OBJECTIVE

To report fertilization and clinical pregnancy rates based on sperm characteristics at the time of intracytoplasmic sperm injection (ICSI) in men with nonobstructive azoospermia (NOA) following microdissection testicular sperm extraction (mTESE).

DESIGN

Retrospective cohort.

SETTING

Tertiary hospital.

PATIENT(S)

Men with NOA undergoing mTESE between 2013 and 2016 who had successful sperm retrieval and subsequent spermatozoa available for ICSI.

INTERVENTION(S)

Sperm characteristic assessment.

MAIN OUTCOME MEASURE(S)

Fertilization and clinical pregnancy rates.

RESULT(S)

One hundred ninety-eight men with NOA and successful mTESE were included. The mean ages of the patients and their partners were 35 ± 8 and 31 ± 5 years, respectively. The overall fertilization rate was 44%, and the clinical pregnancy rate was 38%. The absence of twitching sperm motility and the presence of an acrosome defect were associated with decreased fertilization and clinical pregnancy rates on univariable analysis. On multivariable analysis, the presence of motility was associated with higher fertilization rates and greater odds of clinical pregnancy (odds ratio, 4.37; 95% confidence interval, 1.61-11.85). An abnormal acrosome was associated with reduced odds of pregnancy (odds ratio, 0.40; 95% confidence interval, 0.18-0.85). No specific anomaly or combination of sperm abnormalities precluded fertilization or clinical pregnancy with ICSI.

CONCLUSION(S)

To our knowledge, this is the first comprehensive study evaluating the importance of sperm characteristics and their impact on ICSI outcomes in men with NOA. The results suggest that no specific defect, including the use of nonmotile testicular spermatozoa, precluded a chance of clinical pregnancy. The study evaluated sperm characteristics at the time of ICSI injection; initial evaluation at the time of retrieval may differ significantly from that of spermatozoa selected for ICSI.

Ejaculatory dysfunction in men with diabetes mellitus

Diabetes mellitus (DM) is a metabolic disorder that is characterized by elevated blood glucose levels due to absolute or relative insulin deficiency, in the background of β-cell dysfunction, insulin resistance, or both. Such chronic hyperglycemia is linked to long-term damage to blood vessels, nerves, and various organs. Currently, the worldwide burden of DM and its complications is in increase. Male sexual dysfunction is one of the famous complications of DM, including abnormal orgasmic/ejaculatory functions, desire/libido, and erection. Ejaculatory dysfunction encompasses several disorders related to DM and its complications, such as premature ejaculation, anejaculation (AE), delayed ejaculation, retrograde ejaculation (RE), ejaculatory pain, anesthetic ejaculation, decreased ejaculate volume, and decreased force of ejaculation. The problems linked to ejaculatory dysfunction may extend beyond the poor quality of life in diabetics as both AE and RE are alleged to alter the fertility potential of these patients. However, although both diabetes patients and their physicians are increasingly aware of diabetic ejaculatory dysfunction, this awareness still lags behind that of other diabetes complications. Therefore, all these disorders should be looked for thoroughly during the clinical evaluation of diabetic men. Besides, introducing the suitable option and/or maneuvers to treat these disorders should be tailored according to each case. This review aimed to explore the most important findings regarding ejaculatory dysfunction in diabetes from pre-clinical and clinical perspectives.

Complete Chromatin Decondensation of Pig Sperm Is Required to Analyze Sperm DNA Breaks With the Comet Assay

Sperm quality is usually evaluated prior to artificial insemination in farm animals. In addition to conventional semen analysis, other biomarkers, such as mitochondrial activity, integrity and lipid disorder of plasma membrane, generation of reactive oxygen species (ROS) and sperm DNA integrity, have been found to be related to fertility rates in different species. While mounting evidence indicates that the Comet assay is a sensitive method for the detection of DNA breaks, complete sperm chromatin decondensation is required in order to properly analyze the presence of single- and double-strand DNA breaks. In this sense, a previous study showed that longer lysis treatment with proteinase K is needed to achieve complete chromatin decondensation. The current work sought to determine which specific lysis treatment leads to complete chromatin decondensation in pig sperm, as this is needed for the measurement of DNA damage in this species. With this purpose, incubation with a lysis solution containing proteinase K for 0, 30, and 180 min was added to the conventional protocol. The impact of the DNA damage induced by hydrogen peroxide (H₂O₂; 0.01 and 0.1%) and DNAse I (1U and 4U) was also evaluated. Complete chromatin decondensation was only achieved when a long additional lysis treatment (180 min) was included. Furthermore, olive tail moment (OTM) and percentage of tail DNA (TD) indicated that a higher amount of DNA breaks was detected when hydrogen peroxide and DNAse I treatments were applied (P < 0.05). The comparison of treated and control sperm allowed defining the thresholds for OTM; these thresholds revealed that the percentage of sperm with fragmented DNA determined by the alkaline Comet does not depend on chromatin decondensation (P > 0.05). In conclusion, complete chromatin decondensation prior to alkaline and neutral Comet assays is needed to analyze DNA breaks in pig sperm.

Assessing the cognitive and behavioral development of 3-year-old children born from fathers with severe male infertility

BACKGROUND

Despite the large number of babies born worldwide following intracytoplasmic sperm injection, concerns about the procedure's safety still exist owing to the use of suboptimal spermatozoa. Thus, follow-up of children conceived via intracytoplasmic sperm injection is highly recommended. We propose the use of parent-administered questionnaires to monitor the development of offspring conceived via intracytoplasmic sperm injection.

OBJECTIVE

This study aimed to determine whether male infertility treatment affects offspring development.

STUDY DESIGN

We compared obstetrical and neonatal outcomes and physical and psychological development of toddlers conceived via in vitro fertilization and intracytoplasmic sperm injection. Once newborns reached 3 years of age, participating patients were sent a set of parent-administered questionnaires, including the Ages and Stages Questionnaires; Prescreening Developmental Questionnaire 2; Peabody Developmental Motor Scales, Second Edition; Social Skills Rating System; Parenting Stress Index, Third Edition; and Child Behavior Checklist for Ages 2-3. Child development was measured by the Ages and Stages Questionnaires; Prescreening Developmental Questionnaire 2; and Peabody Developmental Motor Scales, Second Edition, questionnaires, whereas Social Skills Rating System; Parenting Stress Index, Third Edition; and Child Behavior Checklist for Ages 2-3 questionnaires were used to measure child behavior. The child's developmental or behavioral outcome was considered "abnormal" when he or she scored below average in ≥2 questionnaires from the respective category. We also conducted subanalyses to assess the effects of male genomic integrity, DNA fragmentation, chemical exposure, utilization of surgically retrieved spermatozoa, and extended embryo culture to determine the development of a child conceived via intracytoplasmic sperm injection.

RESULTS

A total of 12,306 couples met the inclusion criteria for this study; 1914 of 7433 patients (25.8%) who underwent intracytoplasmic sperm injection and 451 of 4873 patients (9.3%) who underwent in vitro fertilization returned the questionnaires. Our comparison of obstetrical outcomes between the 2 groups did not reveal any significant differences in the mode of delivery distribution, with most mothers having uncomplicated vaginal deliveries. Furthermore, gender distribution, gestational ages, and birthweights were also comparable between children conceived via intracytoplasmic sperm injection and in vitro fertilization. However, children conceived via in vitro fertilization displayed impaired developmental characteristics compared with the intracytoplasmic sperm injection-conceived cohort (adjusted odds ratio, 0.72; 95% confidence interval, 0.5-0.9; P=.0004). There was no difference in child behavior. Furthermore, 3 cases of autism were reported, 1 case from the in vitro fertilization group and 2 from the intracytoplasmic sperm injection group, all conceived from couples with an older male partner. Ages and Stages Questionnaires outcomes were also compared for the offspring conceived via in vitro fertilization and intracytoplasmic sperm injection by gender; however, no significant differences were observed. In addition, 5 separate subanalyses were then conducted exclusively for the intracytoplasmic sperm injection-conceived group. Levels of spermatogenic failure, DNA fragmentation, and chemical exposure did not significantly affect offspring development. Interestingly, although the length of embryo culture did not seem to influence child development, the abnormal behavior rate was significantly higher in children from the day 3 embryo transfer cohort (adjusted odds ratio, 0.4; 95% confidence interval, 0.05-0.34; P=.04). Children conceived via intracytoplasmic sperm injection from ejaculated spermatozoa displayed impaired developmental and behavioral characteristics compared with toddlers conceived from surgically retrieved specimens (adjusted odds ratio, 4.9; 95% confidence interval, 1.2-20.7; P=.05).

CONCLUSION

Most children conceived via intracytoplasmic sperm injection and in vitro fertilization are developing well without significant delays. Although the development of a child conceived via intracytoplasmic sperm injection was not affected by most of the variables assessed, those conceived from surgically retrieved spermatozoa were at a considerably lower risk of abnormal developmental and abnormal behavioral characteristics than offspring conceived from ejaculated specimens. However, given the small numbers of respondents available for many subgroups of interest, further studies of outcomes of children born from fathers with severe male factor infertility are warranted.

The effect of ICSI-related procedural timings and operators on the outcome

STUDY QUESTION

Do the ICSI-related procedural timings and operators affect the outcomes of an ART cycle?

SUMMARY ANSWER

The ICSI-related timings and operators do not associate with the mean blastulation rate per cohort of inseminated oocytes and the cumulative delivery rate per concluded cycle, except for a mild association between the times from induction of ovulation to oocyte denudation and the former outcome.

WHAT IS KNOWN ALREADY

In ART, specific timings, protocols and conditions must be complied with to preserve gamete developmental and reproductive competence during the required manipulations. ICSI represents a groundbreaking advancement that has been widely implemented. Nevertheless, the studies that examined the putative impact of ICSI-related procedural timings were mainly conducted in old-fashioned settings or in good prognosis patients. No report addressed issues like operators' skills and experience and uncertainties exist dealing with the effect of cumulus cells in the pre-incubation period in vitro before ICSI. However, all this information is crucial to efficiently plan the daily routine of an IVF lab, fill the existing gaps of knowledge and define proper key performance indicators.

STUDY DESIGN, SIZE, DURATION

Observational study conducted at a private IVF clinic (January 2016 to January 2018). We included all consecutive ICSI procedures (n = 1084 infertile couples undergoing 1444 cycles with or without preimplantation genetic testing (PGT); mean ± SD maternal age: 38.1 ± 4.0 years) with fresh autologous oocytes (n = 7999 oocytes, 5.5 ± 3.2 per treatment) inseminated with fresh non-donor ejaculated sperm. All operators and critical procedural timings (induction of ovulation to oocyte denudation, denudation and ICSI) were automatically recorded through an electronic witnessing system. The primary outcome measure was the cumulative delivery rate among both non-PGT and PGT-concluded cycles (i.e. delivery achieved or no supernumerary cryopreserved blastocyst available). The secondary outcome measure was the mean blastulation rate per cohort of inseminated oocytes. All confounders were registered and included in generalized linear models and multivariate logistic regression analyses.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Fourteen and 12 operators were involved in denudation and ICSI procedures, respectively. Denudation was performed after 4.1 ± 1.2 h (2-7) of pre-incubation in vitro after oocyte retrieval, and ICSI was started immediately after. Beyond procedural timings and operators, all the putative confounders (patients' and cycles' characteristics) on the primary and/or secondary outcomes were systematically registered and included in the statistical analyses.

MAIN RESULTS AND THE ROLE OF CHANCE

The mean time from induction of ovulation to oocyte denudation was 39.3 ± 1.3 h. The mean procedural timings for denudation and ICSI were 8.1 ± 3.8 and 12.6 ± 6.4 min; both these variables were significantly dependent on the number of inseminated oocytes and the operators' skills and experience. The overall mean blastulation rate per cohort of inseminated oocytes was 34.0 ± 27.9%. This outcome was significantly associated with the time from induction of ovulation to oocyte denudation (mean blastulation rate stable in the time interval 38-42 h, but significantly higher for timings <38 h), maternal age (the mean blastulation rate drops especially beyond the age of 40 years) and categorized sperm concentration (highest mean blastulation rate for sperm concentrations ≥15 mil/ml and lowest for cryptozoospermic patients) through a generalized linear model that showed an adjusted r2 = 0.053 (P < 0.01). No association was found for denudation and ICSI timings and operators. Lastly, when adjusted for maternal age and number of inseminated oocytes, both ICSI-related procedural timings and operators did not associate with the cumulative delivery rate among both non-PGT- or PGT-concluded cycles.

LIMITATIONS, REASONS FOR CAUTION

This is a single private IVF center study. Its reproducibility should be assessed in different laboratory conditions, with different protocols and in the hands of different operators. Moreover, specific studies are warranted to address the beneficial/detrimental effect of the other putative confounders under investigation (e.g. kind of ovulation trigger, culture media, incubator, etc.).

WIDER IMPLICATIONS OF THE FINDINGS

Proactive communication between the embryologists and the clinicians might contribute to a reasoned and more efficient organization of the daily workload and increase the mean blastulation rate, especially when poor prognosis couples (advanced maternal age, reduced sperm count and/or ovarian reserve) are treated.

STUDY FUNDING/COMPETING INTEREST(S)

No funding. The authors declare no conflict of interest related to the present study.

Novel mutations in PLCZ1 cause male infertility due to fertilization failure or poor fertilization

STUDY QUESTION

Do sperm-specific phospholipase C zeta (PLCZ1) mutations account for male infertility due to fertilization failure?

SUMMARY ANSWER

Six novel mutations and one reported mutation in PLCZ1 were identified in five of 14 independent families characterized by fertilization failure or poor fertilization, suggesting that these mutations may be responsible for fertilization failure in men exhibiting primary infertility.

WHAT IS KNOWN ALREADY

PLCZ1 is essential for the induction of intracellular calcium (Ca2+) oscillations and the initiation of oocyte activation during mammalian fertilization. However, genetic evidence linking PLCZ1 mutations with male infertility remains limited.

STUDY DESIGN, SIZE, DURATION

Fourteen unrelated primary infertility patients were recruited into this study from January 2016 to December 2018; the patients exhibited total fertilization failure or poor fertilization, as evidenced by ICSI and sperm-related oocyte activation deficiencies identified in mouse oocyte activation assays.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Genomic DNA samples were extracted from the peripheral blood of patients. The whole exons of PLCZ1 were sequenced by Sanger sequencing. The PLCZ1 sequences were aligned by CodonCode software to identify rare variants. The ExAC database was used to search for the frequency of corresponding mutations. The pathogenicity of identified variants and their possible effects on the protein were assessed in silico. PLCZ1 protein levels in semen samples were evaluated by western blotting. Oocyte activation ability was assessed by the injection of wild-type and mutant PLCZ1 cRNAs into human mature metaphase II (MII) oocytes in vitro.

MAIN RESULTS AND THE ROLE OF CHANCE

We identified six novel mutations and one reported mutation in PLCZ1 among five affected individuals. In addition to four novel missense mutations, two new types of genetic variants were identified, including one in-frame deletion and one splicing mutation. Western blot analysis revealed that PLCZ1 protein expression was not observed in the semen samples from the five affected patients. Microinjection with the PLCZ1 cRNA variants was performed, and a significant decrease in the percentage of pronuclei was observed for four novel missense mutations and one novel in-frame deletion mutation, suggesting that these mutations have a deleterious influence on protein function. By artificial oocyte activation treatment, the fertilization failure phenotypes of four affected patients were successfully rescued and three healthy babies were delivered.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

We screened only the whole exons of PLCZ1. Additional possible mutations in the non-coding region of PLCZ1 should be further studied.

WIDER IMPLICATIONS OF THE FINDINGS

Our study not only further confirms the important role of PLCZ1 in human fertilization but also expands the mutational spectrum of PLCZ1 associated with male infertility, which provides a basis for assessing genetic variation in PLCZ1 as a potential diagnostic marker for infertile men suffering from fertilization failure.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by the National Natural Foundation of China (81 571 486 and 81 771 649). All authors have no conflicts of interest to declare.

Circulating MMP-7 and VEGF as potential predictive biomarkers for recurrent implantation failures

Recurrent implantation failure (RIF) is considered to be one of the major limiting factors of assisted reproductive technology (ART) programme success. The current study focused on the investigation of matrix metalloproteinases (MMPs), tissue inhibitors of MMPs (TIMPs), cytokines and cell adhesion molecules in peripheral blood (PB) and follicular fluid (FF) obtained from 44 women aged between 25 and 39 years old and undergoing intracytoplasmic sperm injection (ICSI). These women were divided into two groups: 22 RIF women with embryo implantation failures after the transfer of at least four fresh or frozen-thawed good quality embryos in a minimum of three ICSI cycles, and 22 ICSI success women (controls) who achieved a clinical pregnancy at their first ICSI attempt. The PB and FF samples were obtained from each patient on the day of oocyte retrieval. MMP-1, -2, -3, -7, -9, TIMP-1, -2, vascular endothelial growth factor (VEGF), leukaemia inhibitory factor (LIF), vascular cell adhesion molecule 1 (VCAM1) and intercellular adhesion molecules 1 (ICAM1) were analyzed using enzyme-linked immunosorbent assay of PB and FF. Our results showed significant decreases in PB MMP-7 and PB VEGF in the RIF group compared with controls [281.11 (33-614) pg/ml vs 119.92 (27-441) pg/ml; P-value = 0.030] and [82.54 (25.94-210.20) pg/ml vs 30.93 (13.62-193.33) pg/ml; P-value = 0.022; respectively]. Receiver operating characteristic (ROC) curve analysis showed informative area under the curve values for PB MMP-7, as well as for PB VEGF, making them able to be proposed as biomarkers of the RIF. Therefore, circulating MMP-7 and VEGF seem to play an interesting role in embryo implantation in in vitro fertilization (IVF)/ICSI cycles and could be proposed as circulating biomarkers of the RIF. These results could be helpful for clinicians and patients to choose the best rescue strategy and treatment to minimize implantation failure in women undergoing IVF/ICSI procedures after the first attempt.

Sperm selection during ICSI treatments reduces single- but not double-strand DNA break values compared to the semen sample

PURPOSE

To detect a possible bias in sperm DNA fragmentation (SDF) testing when performed on semen samples or on those few spermatozoa selected for Intracytoplasmic Sperm Injection (ICSI) treatments.

METHODS

A multimethodological analysis of Single- and Double-Strand DNA Breaks (SSB and DSB, respectively) was performed through the Neutral Comet, the Alkaline Comet, the Sperm Chromatin Dispersion (SCD) and the Terminal deoxynucleotidyl transferase dUTP Nick End Labelling (TUNEL) assays. SDF was evaluated in (i) semen samples from 23 infertile patients (not achieving pregnancy or suffering recurrent miscarriage); (ii) samples after a Swim-up and (iii) spermatozoa microselected for ICSI (ICSI-S).

RESULTS

The analysis of 3217 ICSI-S revealed a significant reduction of SSB values compared to the Ejaculate and the Swim-up samples. On the contrary, DSB values were not reduced after any sperm selection method. The No-pregnancy group presented poorer semen parameters and higher SSB values. The Recurrent miscarriage group presented better semen parameters but also higher DSB values.

CONCLUSION

The analysis of SDF on semen samples may not be fully representative of those few spermatozoa selected for ICSI. Since oxidative stress impairs sperm motility and causes SSB, selecting a motile sperm may intrinsically imply choosing a sperm not affected by this damage. DSB have an enzymatic origin which does not affect motility, making it difficult to select a sperm without this damage. Therefore, ICSI treatments could be effective in patients presenting high SSB values. Patients presenting high DSB values should expect bad ICSI results if this damage is not reduced through other specific methods.

Dynamics of endoreduplication in developing barley seeds

Seeds are complex biological systems comprising three genetically distinct tissues: embryo, endosperm, and maternal tissues (including seed coats and pericarp) nested inside one another. Cereal grains represent a special type of seeds, with the largest part formed by the endosperm, a specialized triploid tissue ensuring embryo protection and nourishment. We investigated dynamic changes in DNA content in three of the major seed tissues from the time of pollination up to the dry seed. We show that the cell cycle is under strict developmental control in different seed compartments. After an initial wave of active cell division, cells switch to endocycle and most endoreduplication events are observed in the endosperm and seed maternal tissues. Using different barley cultivars, we show that there is natural variation in the kinetics of this process. During the terminal stages of seed development, specific and selective loss of endoreduplicated nuclei occurs in the endosperm. This is accompanied by reduced stability of the nuclear genome, progressive loss of cell viability, and finally programmed cell death. In summary, our study shows that endopolyploidization and cell death are linked phenomena that frame barley grain development.

Influence of sperm morphology on pregnancy outcome and offspring in in vitro fertilization and intracytoplasmic sperm injection: a matched case-control study

Sperm morphology was once believed as one of the most predictive indicators of pregnancy outcome in assisted reproductive technology (ART). However, the impact of teratozoospermia on in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) outcomes and its offspring remains inconclusive. In order to evaluate the influence of teratozoospermia on pregnancy outcome and newborn status after IVF and ICSI, a retrospective study was conducted. This was a matched case-control study that included 2202 IVF cycles and 2574 ICSI cycles and was conducted at the Reproductive and Genetic Hospital of CITIC-Xiangya in Changsha, China, from June 2013 to June 2018. Patients were divided into two groups based on sperm morphology: teratozoospermia and normal sperm group. The pregnancy outcome and newborn outcome were analyzed. The results indicated that couples with teratozoospermia had a significantly lower optimal embryo rate compared to those with normal sperm morphology in IVF (P = 0.007), while there were no statistically significant differences between the two groups in terms of the fertilization rate, cleavage rate, implantation rate, and pregnancy rate (all P > 0.05). Additionally, teratozoospermia was associated with lower infant birth weight in multiple births after IVF. With regard to ICSI, there was no significant difference in both pregnancy outcome and newborn outcome between the teratozoospermia and normal groups (both P > 0.05). Furthermore, no increase in the risk of birth defects occurred in the teratozoospermia group after IVF/ICSI. Consequently, we believe that teratozoospermia has limited predictive value for pregnancy outcomes in IVF/ICSI, and has little impact on the resulting offspring if multiple pregnancy is avoided.

Risk of neurodevelopmental disorders in children born from different ART treatments: a systematic review and meta-analysis

BACKGROUND

Various techniques in assisted reproductive technology (ART) have been developed as solutions for specific infertility problems. It is important to gain consensual conclusions on the actual risks of neurodevelopmental disorders among children who are born from ART. This study aimed to quantify the relative risks of cerebral palsy, intellectual disability, autism spectrum disorder (ASD), and behavioral problems in children from different ART methods by using systematic review and meta-analysis. Healthcare providers could use the results of this study to suggest the suitable ART technique and plan optimum postnatal care.

METHODS

Pubmed, Google Scholar, and Scopus databases were used to search for studies up to January 2020. Of the 181 screened full manuscripts, 17 studies (9.39%) fulfilled the selection criteria. Based on the Newcastle-Ottawa scale ratings, 7 studies were excluded, resulting in 10 studies that were eventually included in the meta-analyses. Mantel-Haenszel risk ratio model was used in the meta-analysis, and the results are described using forest plot with 95% confidence interval. Heterogeneity was assessed using the I² value.

RESULTS

Pooled evaluation of 10 studies showed that the risk of cerebral palsy in children from assisted reproductive technology (ART) is higher than children from natural conceptions (risk ratio [RR] 1.82, [1.41, 2.34]; P = 0.00001). Risk of intellectual disability (RR 1.46, [1.03, 2.08]; P = 0.03) and ASD (RR 1.49 [1.05, 2.11]; P = 0.03) are higher in intracytoplasmic sperm injection (ICSI) children compared to conventional in vitro fertilization (IVF) children. The differences in the risk of neurodevelopmental disorders in children born after frozen and fresh embryo transfers are not significant. Analysis on potential cofounder effects, including multiple birth, preterm birth, and low birth body weight highlight possibilities of significant correlation to the risks of neurodevelopmental disorders.

CONCLUSIONS

Pooled estimates suggest that children born after ART are at higher risk of acquiring cerebral palsy. ICSI treatment causes higher risk of intellectual disability and ASD. These findings suggest the importance of the availability of intensive care unit at the time of delivery and long-term developmental evaluation particularly in children from ICSI.

Diagnosis and Treatment of Male Infertility-Related Fertilization Failure

Infertility affects approximately 15% of reproductive-aged couples worldwide, of which up to 30% of the cases are caused by male factors alone. The origin of male infertility is mostly attributed to sperm abnormalities, of which many are caused by genetic defects. The development of intracytoplasmic sperm injection (ICSI) has helped to circumvent most male infertility conditions. However, there is still a challenging group of infertile males whose sperm, although having normal sperm parameters, are unable to activate the oocyte, even after ICSI treatment. While ICSI generally allows fertilization rates of 70 to 80%, total fertilization failure (FF) still occurs in 1 to 3% of ICSI cycles. Phospholipase C zeta (PLCζ) has been demonstrated to be a critical sperm oocyte activating factor (SOAF) and the absence, reduced, or altered forms of PLCζ have been shown to cause male infertility-related FF. The purpose of this review is to (i) summarize the current knowledge on PLCζ as the critical sperm factor for successful fertilization, as well as to discuss the existence of alternative sperm-induced oocyte activation mechanisms, (ii) describe the diagnostic tests available to determine the cause of FF, and (iii) summarize the beneficial effect of assisted oocyte activation (AOA) to overcome FF.

A scientometric analysis of research publications on male infertility and assisted reproductive technology

Assisted reproductive technologies (ART) are considered as one of the primary management options to address severe male factor infertility. The purpose of this study was to identify the research trends in the field of male infertility and ART over the past 20 years (2000-2019) by analysing scientometric data (the number of publications per year, authors, author affiliations, journals, countries, type of documents, subject area and number of citations) retrieved using the Scopus database. We used VOS viewer software to generate a network map on international collaborations as well as a heat map of the top scientists in this field. Our results revealed a total of 2,148 publications during this period with Cleveland Clinic Foundation contributing the most (n = 69). The current scientometric analysis showed that the research trend on ART has been stable over the past two decades. Further in-depth analysis revealed that density gradient centrifugation (46%) and intracytoplasmic sperm injection (59.2%) are the most reported techniques for sperm separation and ART, respectively. Additionally, azoospermia was the most studied clinical scenario (60.6%), with majority of articles reporting pregnancy rate (47.25%) as the primary reproductive outcome for ART. This study provides insight into the current focus of research in the area of male infertility and ART as well as the areas that require further research in future.

Assessment of operant learning and memory in mice born through ICSI

STUDY QUESTION

Are there differences in operant learning and memory between mice born through ICSI and naturally conceived control (CTL) mice?

SUMMARY ANSWER

ICSI females exhibited deficits in the acquisition reward learning relative to CTL females, and ICSI males exhibited deficiencies in discrimination learning and memory relative to CTL males.

WHAT IS KNOWN ALREADY

Some human outcome studies have suggested that ICSI might be associated with an increased risk of certain cognitive disorders, but only one of two behavioral studies with ICSI mouse models have reported differences between ICSI and CTL females. No studies to date have investigated associative learning in ICSI mice.

STUDY DESIGN, SIZE, DURATION

Groups of 36 ICSI mice (18 male, 18 female) and 37 CTL mice (19 male, 18 female) aged 3-6 months were compared in a series of operant learning procedures that assessed acquisition of a new behavior, discrimination learning and memory. In total, 16 ICSI mice (9 male, 7 female) and 17 CTL mice (10 male, 7 female) received follow-up discrimination learning and memory assessments at 12 months of age (6 months after the end of initial training) to evaluate retention and reacquisition of learned performances.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Mice received daily operant learning sessions in experimental chambers in which all stimulus events and the recording of responses were automated. Food rewards were delivered for responding under different conditions of reinforcement, which varied by procedure. Subjects received a successive series of sessions of nose poke acquisition training, discrimination training and the delayed-non-matching-to-position memory procedure. Mixed repeated measures ANOVAs in which the between-subjects factor was group (ICSI vs CTL) and the within-subjects factor was repeated exposures to learning procedures (i.e. sessions) were used to analyze data.

MAIN RESULTS AND THE ROLE OF CHANCE

In comparisons between all mice (i.e. males and females combined), CTL mice exhibited superior performance relative to ICSI in response acquisition (P = 0.03), discrimination (P = 0.001) and memory (P = 0.007). Sex-specific comparisons between the groups yielded evidence of sexual dimorphism. ICSI females exhibited a deficit in acquisition learning relative to CTL females (P < 0.001), but there was not a significant difference between CTL and ICSI males. In the discrimination and memory tasks, ICSI males exhibited deficits relative to CTL males (P = 0.002 and P = 0.02, respectively) but the differences between females in these tasks were not significant. There was no difference in discrimination or memory retention/re-acquisition assessments conducted with mice at 12 months of age. ICSI males and females weighed significantly more than CTL counterparts at all points during the experiment.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The study was not blinded. All learning assessments utilized food reward; other assessments of operant, Pavlovian and nonassociative learning are needed to fully characterize learning in ICSI mice and speculate regarding the implications for cognitive function in humans conceived via ICSI.

WIDER IMPLICATIONS OF THE FINDINGS

Studying learning and memory processes in mouse models have the potential to shed light on ICSI outcomes at the level of cognitive function. Future research should use multiple learning paradigms, assess both males and females, and investigate the effects of variables related to the ICSI procedure. Studying cognitive function in ICSI is an interdisciplinary endeavor and requires co-ordination between researchers at the genetic and psychological levels of analysis.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported, in part, by grants from the NIH (P30GM110767, HD071736 and HD085506 to W.Y.), the Templeton Foundation (61174 to W.Y.) and a New Scholarly Endeavor Grant from the University of Nevada, Reno Office of Research and Innovation (to M.L., Y.W., H.Z., L.H. and W.Y.). The authors declare no competing interests.

The practice of intracytoplasmic sperm injection in Jordan: A clinical outcome study

Objective

The lack of appropriate guidelines and justified practice in most developing countries is a serious limitation to efforts to qualify the services provided. In this paper, we evaluate and assess the clinical practice of an assisted reproductive technique of intracytoplasmic sperm injection (ICSI) in Jordan.

Methods

Retrospectively, we identified women who achieved a successful pregnancy by ICSI over a period of ten years. Information related to the ICSI procedure, foetus abnormalities, maternal complications and delivery outcomes were included. A control group of normal pregnancies were incorporated.

Results

In total, 291 cases were included as successful cases of ICSI with a success rate of 14.1%. For the control group, 466 pregnant women with normal pregnancies were included. No statistical difference was observed between both groups in foetus malformation. In normal pregnancy women, 42.1% delivered through caesarean section (CS) while 87.6% of ICSI patients underwent CS. Women with ICSI had significantly higher rates of multiple gestations, and their neonates were lower in birthweight. Women in the ICSI group tended to deliver females compared to the control group. Pregnancy-related hypertension was more commonly reported in the normal pregnancy group, while gestational diabetes, antepartum haemorrhage and preterm labour were more common in ICSI group.

Conclusion

Services for the management of infertility are increasing in the Middle East. The clinical outcomes in Jordan is approaching that of other developed regions, although the success rate is lower than in other regions. Further studies and efforts should be carried out to maximize effective and successful practice in such low-income areas.

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The practice of ICSI needs to be justified in the developing countries.

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The success rate of ICSI is low with higher rates of CS and multiple gestation.

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Neonates for women with ICSI are born with lower birth weight.

Effects of testicular sperm aspiration upon first cycle ICSI-ET for type 2 diabetic male patients

Male diabetes mellitus (DM) can affect erectile function and sperm quality. In severe cases, DM can lead to retrograde or no ejaculation, so testicular sperm aspiration (TESA) is combined with intracytoplasmic sperm injection (ICSI) to treat subfertility and infertility for DM couples. However, the effect of TESA upon ICSI (TESA-ICSI) for DM patients remains unclear. This research investigated the effect of TESA-ICSI on first cycle ICSI-embryo transfer (ICSI-ET) for type 2 diabetic mellitus (T2DM) patients and the potential mechanisms. The subjects consisted of 1219 male patients with azoospermia or retrograde ejaculation who were treated with TESA-ICSI from 2015.01 to 2019.11. They were classified into two groups, the T2DM group (n = 54) and non-diabetic control group (n = 1165). Sperm selection for injection was performed using motile sperm organelle morphology examination criteria. The number of available embryos and the high-quality embryo rates following a single ET as well as cleavage, fertilization, implantation, clinical pregnancy and the abortion rates were noted. Compared with the non-diabetic group, the available embryo rate (75.20 ± 26.40% vs.78.36 ± 23.25%) and high-quality embryo rate (46.49 ± 30.37% vs. 47.55 ± 28.57%) in the T2DM group were lower and the abortion rate (20.83% vs. 8.88%) was higher, but these differences were not statistically significant. There were no significant differences in clinical pregnancy, implantation, normal fertilization, and cleavage rates between the two groups. The results show that TESA for male T2DM patients does not influence the effect of ICSI. For T2DM patients with severe oligozoospermia, asthenospermia, teratozoospermia, or retrograde ejaculation that do not meet ICSI criteria, TESA-ICSI may perhaps be considered for reproductive assistance.

ABBREVIATIONS

DM: diabetes mellitus; TESA: testicular sperm aspiration; ICSI: intracytoplasmic sperm injection; ICSI-ET; ICSI-embryo transfer; LH: luteinizing hormone; mL: milliliter; TES: testosterone; FSH: follicle-stimulating hormone; P: progesterone; HCG: human chorionic gonadotropin.

Comparison of Sperm Telomere Length between Two Sperm Selection Procedures: Density Gradient Centrifugation and Zeta Potential

Background

Telomeres are particular sequences of DNA located at the end of the eukaryotic chromosomes that are essential for genome integrity. Telomere length in spermatozoa differs among males, as well as spermatozoa. Also, decreased telomere length in spermatozoa of infertile men is associated with the reduction of fertility potential and embryo quality. Density gradient centrifugation (DGC) and swim-up are useful techniques for separation of spermatozoa with longer telomeres. Also, the selection of sperm based on surface negative electric charge or "Zeta potential", can separate high percentage of spermatozoa with intact chromatin compared to DGC alone, and also the combination of DGC-Zeta can improve clinical outcomes of infertile men candidate for intracytoplasmic sperm injection (ICSI). Therefore, we compared sperm telomere length and DNA fragmentation between two sperm preparation procedures, namely DGC and zeta potential.

Materials and Methods

In this experimental study, we assessed sperm telomere length and DNA fragmentation by quantitative real-time polymerase chain reaction (PCR) and TUNEL assay methods, respectively. The spermatozoa were obtained from infertile men with normozoospermia between September 2017 and December 2017 and prepared either by DGC or zeta potential methods. Sperm telomere length was expressed as relative and absolute units.

Results

Compared with washed semen samples or control, no significant (P>0.05) difference was observed in the mean relative or absolute sperm telomere length when the two methods DGC or zeta potential were compared. However, the mean percentage of DNA fragmentation was significantly (P<0.05) lower in spermatozoa prepared by DGC or zeta potential methods than spermatozoa obtained from control samples.

Conclusion

This is the first study that compared the effect of DGC and zeta potential as the sperm preparation methods on sperm telomere length. It seems that both methods can select sperm population with high DNA integrity and the same sperm telomeres length.

Proven and unproven methods for diagnosis and treatment of infertility

Infertility and subfertility affect a significant part of the population. Among various definitions of this pathology, the most common one is provided by the World Health Organisation; it says that infertility is 'a disease of the reproductive system defined by the failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sexual intercourses'. The global prevalence of infertility is about 50-70 million couples. Since the process of human reproduction involves a large number of factors, a broad spectrum of infertility tests might be applied. Some of the tests focus directly on the pregnancy, some are only partially effective, whereas others should not be recommended for infertile couples. The aim of this review is to present a critical evaluation of the infertility diagnostic process and to discuss the recommendations for its most effective treatment.

Intracytoplasmic sperm injection and fetal origins of autism spectrum disorder: an intriguing, though controversial association

Latest knowledge assigns the origins of autism spectrum disorder (ASD)-currently affecting 1% of children- to intrauterine life, when fetal brain develops. Besides genetics, environmental factors, responsible for epigenetic changes contributed to its rising incidence. In vitro fertilization (IVF) and the most widely used intracytoplasmic sperm injection (ICSI) are implicated in epigenetic changes. A series of studies examined the impact of ICSI on ASD in the offspring. Results are usually conflicting, due to inherent problems of study design and power, mixed IVF/ICSI cases and not exclusively ASD diagnoses included. Furthermore, preterm birth, low birthweight infants, advanced parental age, hormonal disturbances, all associated with ICSI, are known factors affecting ASD. While solid data supporting ICSI contribution to currently alarming ASD increase are lacking, exploration of underlying molecular mechanisms would strengthen possible associations. In the meanwhile, ICSI use should be restricted to male-factor infertility cases.

Transient Sperm Starvation Improves the Outcome of Assisted Reproductive Technologies

To become fertile, mammalian sperm must undergo a series of biochemical and physiological changes known as capacitation. These changes involve crosstalk between metabolic and signaling pathways and can be recapitulated in vitro. In this work, sperm were incubated in the absence of exogenous nutrients (starved) until they were no longer able to move. Once immotile, energy substrates were added back to the media and sperm motility was rescued. Following rescue, a significantly higher percentage of starved sperm attained hyperactivated motility and displayed increased ability to fertilize in vitro when compared with sperm persistently incubated in standard capacitation media. Remarkably, the effects of this treatment continue beyond fertilization as starved and rescued sperm promoted higher rates of embryo development, and once transferred to pseudo-pregnant females, blastocysts derived from treated sperm produced significantly more pups. In addition, the starvation and rescue protocol increased fertilization and embryo development rates in sperm from a severely sub-fertile mouse model, and when combined with temporal increase in Ca²⁺ ion levels, this methodology significantly improved fertilization and embryo development rates in sperm of sterile CatSper1 KO mice model. Intracytoplasmic sperm injection (ICSI) does not work in the agriculturally relevant bovine system. Here, we show that transient nutrient starvation of bovine sperm significantly enhanced ICSI success in this species. These data reveal that the conditions under which sperm are treated impact post-fertilization development and suggest that this “starvation and rescue method” can be used to improve assisted reproductive technologies (ARTs) in other mammalian species, including humans.

Fertilization and Cleavage Axes Differ In Primates Conceived By Conventional (IVF) Versus Intracytoplasmic Sperm Injection (ICSI)

With nearly ten million babies conceived globally, using assisted reproductive technologies, fundamental questions remain; e.g., How do the sperm and egg DNA unite? Does ICSI have consequences that IVF does not? Here, pronuclear and mitotic events in nonhuman primate zygotes leading to the establishment of polarity are investigated by multidimensional time-lapse video microscopy and immunocytochemistry. Multiplane videos after ICSI show atypical sperm head displacement beneath the oocyte cortex and eccentric para-tangential pronuclear alignment compared to IVF zygotes. Neither fertilization procedure generates incorporation cones. At first interphase, apposed pronuclei align obliquely to the animal-vegetal axis after ICSI, with asymmetric furrows assembling from the male pronucleus. Furrows form within 30° of the animal pole, but typically, not through the ICSI injection site. Membrane flow drives polar bodies and the ICSI site into the furrow. Mitotic spindle imaging suggests para-tangential pronuclear orientation, which initiates random spindle axes and minimal spindle:cortex interactions. Parthenogenetic pronuclei drift centripetally and assemble astral spindles lacking cortical interactions, leading to random furrows through the animal pole. Conversely, androgenotes display cortex-only pronuclear interactions mimicking ICSI. First cleavage axis determination in primates involves dynamic cortex-microtubule interactions among male pronuclei, centrosomal microtubules, and the animal pole, but not the ICSI site.

Female age affects the utility of sperm DNA fragmentation in predicting IVF and ICSI outcomes

RESEARCH QUESTION

The aim of this study was to investigate how female age affects the predictive effect of sperm DNA fragmentation index (DFI) on clinical outcomes with assisted reproductive technology.

DESIGN

A total of 2371 patients, comprising 2115 men with a normal DFI (≤30), 256 men with a high DFI (>30) and women of different ages, were recruited and investigated. All patients had normal chromosome karyotypes and were undergoing their first fresh IVF or intracytoplasmic sperm injection (ICSI) cycles. Clinical outcomes were analysed according to the two DFI groups and female age ≤30 and >30 years. Binary logistic regression analysis was performed to identify factors associated with clinical outcome.

RESULTS

The proportion of couples with at least one good-quality embryo in the DFI ≤30 group was higher than that in the DFI >30 group. When female age exceeded 30 years, clinical pregnancy rate and the proportion of couples with good-quality embryos in the DFI >30 group were lower compared with DFI ≤30; however, there were no differences in outcomes for female age ≤30 years according to DFI. When DFI >30, the cut-off value of female age was 30.5 for detecting clinical pregnancy; the sensitivity was 62.0%, and the specificity was 63.6%. Clinical pregnancy rate and proportion of couples with good-quality embryos were lower in the DFI >30 versus DFI ≤30 group with a female age above 30 years for IVF but not for ICSI.

CONCLUSION

Female age has a negative effect and should be considered in predicting the effects of sperm DNA fragmentation on pregnancy outcomes.

Novel homozygous variations in PLCZ1 lead to poor or failed fertilization characterized by abnormal localization patterns of PLCζ in sperm

Total fertilization failure (TFF), which is the failure of fertilization in all oocytes, occurs in 1%-3% of intracytoplasmic sperm injection (ICSI) cycles. However, the sperm-related factors that cause fertilization failure in humans are still largely unknown. Here, we identified three novel homozygous variations in the PLCZ1 gene in a recessive inheritance pattern in three consanguineous families, which all located in a key catalytic domain, and predicted to modify its secondary structure and thus impair its hydrolytic activity. Moreover, immunofluorescent staining revealed that PLCζ in mutant sperm exhibited abnormal localization patterns. ICSI-AOA resulted in an increased rate of normal fertilization compared with previous ICSI cycles (75.0% vs 2.2%, P < .001). In summary, we identified three novel homozygous variations in PLCZ1 that led to poor or failed fertilization that could be overcame by ICSI-AOA.

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.

Failure of complete hatching of ICSI-derived human blastocyst by cell herniation via small slit and insufficient expansion despite ongoing cell proliferation

PURPOSE

To assess the effect of intracytoplasmic sperm injection (ICSI) on embryo hatching and visualise the effects of zona thinning (ZT) on the embryo using time-lapse monitoring.

METHODS

In vitro fertilisation (IVF) (n = 178) and ICSI (n = 110)-derived cryopreserved blastocysts were donated by patients who previously had a baby. This study investigated the impacts of IVF, ICSI, laser-assisted hatching by ZT and formation of ICSI penetration trace on zona pellucida of IVF-derived blastocyst on blastcyst diameter, the estimated number of trophectoderm (TE) cells and completed hatching rate.

RESULTS

The completed hatching rate and diameters of the completely hatched blastocysts at hatching commencement and at the maximum expansion were significantly greater in the IVF than in ICSI groups. The completed hatching rate significantly increased with ZT in both groups. The maximum diameters of the completely hatched blastocysts were significantly smaller in the ZT than in non-ZT groups. The estimated TE cell numbers increased from hatching commencement to their maximum expansion points. The incompletely hatched ICSI-derived blastocysts intermittently herniated cells via small slits until degeneration. The completed hatching rate significantly decreased by the formation of ICSI penetration trace on zona pellucida of IVF-derived blastocyst.

CONCLUSION

ICSI-derived blastocysts intermittently release proliferating cells and extracted TE cells and/or inner cell masses via a small slit; thus, blastocyst expansion is not sufficiently increased, leading to a reduced complete hatching rate. Therefore, the ICSI penetration trace potentially has negative effects on blastocyst expansion process in vitro and is a risk factor for the failure of completed hatching.

The effectiveness of ICSI versus conventional IVF in couples with non-male factor infertility: study protocol for a randomised controlled trial

Study questions

Does ICSI result in a higher live birth rate as compared with conventional IVF in couples with non-male factor infertility?

What is known already

ICSI is primarily indicated for severe male factor infertility. While the use of ICSI for couples with non-male factor infertility has been increasing worldwide, this is not supported by data from randomised controlled trials. Evidence from non-randomised studies suggest no benefit from ICSI compared with conventional IVF in non-male factor infertility, if not a harm.

Study design, size, duration

This randomised, open-label, multi-centre trial aims to compare the effectiveness of one ICSI cycle and one conventional IVF cycle in infertile couples with non-male factor infertility. A total of 1064 couples will be randomly allocated to an ICSI group and a conventional IVF group. The estimated duration of the study is 30 months.

Participants/materials, setting, methods

Eligible couples are those whose husbands’ total sperm count and motility are normal, have undergone ≤2 previous IVF/ICSI attempts, use antagonist protocol for ovarian stimulation, agree to have ≤2 embryos transferred and are not participating in another IVF study at the same time. Women undergoing IVM cycles, using frozen semen or having a poor fertilisation (≤25%) in previous cycle will not be eligible. Couples will be randomised to undergo ICSI or conventional IVF (1:1) with ongoing pregnancy resulting in live birth after the first embryo transfer of the started treatment cycle as the primary endpoint. All analyses will be conducted on an intention-to-treat basis. Effect sizes will be summarised as relative risk (RR), with precision evaluated by 95% CIs.

STUDY FUNDING/COMPETING INTEREST(S)

All authors declare having no conflict of interests with regards to this trial. This work was supported by a grant from MSD [MISP #57508].

Trial registration number

NCT03428919.

Trial registration date

8 February 2018.

DATE OF FIRST PATIENT’S ENROLMENT

16 March 2018.