Complete Fertilization Failure Research Articles

Identification of a new mutation in the ACTL9 gene in men with unexplained infertility.

Infertility is defined as the failure to achieve pregnancy after one year of unprotected intercourse within a marital relationship. Approximately 10%-15% of couples worldwide experience infertility issues, with nearly half of these cases attributed to male factors. Among men with unexplained infertility, genetic mutations have been identified as a potential cause. Studies have indicated that mutations affecting the function of the protein encoded by the ACTL9 gene may play a role in male infertility. The purpose of this research was to identify mutations in the ACTL9 gene associated with male infertility in a sample of 40 infertile men with unknown causes. Genomic DNA extraction and PCR amplification were carried out on samples from each individual. The genetic material was then analyzed using Sanger sequencing, followed by bioinformatics and segregation analysis to determine the potential effects of the observed variations. A novel genetic variant, c.376G>A (p.Glu126Lys), was identified in an infertile male individual, representing a previously unreported finding that was validated through segregation analyses. This specific variant induces a change from glutamate to lysine at the amino acid level by replacing the nucleotide G with A in the genomic DNA sequence, consequently impacting the secondary structure and function of the protein. The conclusive analysis of the procedure indicated that this alteration has the potential to interfere with the process of fertilization, ultimately resulting in the complete failure of fertilization (TFF) and causing male infertility.

Sperm acrosin activity may be a useful factor in choosing between ICSI and IVF for infertile male patients.

The clinical applications of acrosin activity are limited. We analyzed 61 578 male partners in infertile couples who visited the outpatient department of the Reproductive and Genetic Hospital of CITIC-Xiangya (Changsha, China) between August 2014 and December 2019 to determine the reference ranges and thresholds for acrosin activity in infertile Chinese men; to determine whether correlations exist between acrosin activity and age, sperm concentration, sperm morphology, or sperm motility; and to evaluate whether acrosin activity could serve as an effective prognostic indicator for choosing between in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) in the clinic. The cut-off value for the normal reference range of acrosin activity for male partners in infertile couples was 24.78 μIU per 106 sperm. There was no significant association between acrosin activity and age, sperm concentration, semen volume, total sperm count, progressive motility, or total motile spermatozoa. A weak positive correlation was found between acrosin activity and normal sperm morphology. There was a statistically significant difference in abnormal acrosome morphology between the group with high acrosin activity (>24.78 μIU per 106 sperm) and the group with low acrosin activity (<24.78 μIU per 106 sperm). The group with a low IVF fertilization rate had a high index of abnormal acrosomal morphology at 21.2%, while the group with a high IVF fertilization rate had a low index of 0.2%. At an acrosin activity of <24.78 µIU per 106 sperm, in one cycle of the same patient, the fertilization rate, normal fertilization rate, and good-quality embryo rate for ICSI were significantly higher than those for IVF. Therefore, the most promising application of acrosin activity could be in the selection of ICSI over IVF for infertile male patients with complete fertilization failure or a low fertilization rate.

Transition nuclear protein 1 as a novel biomarker in patients with fertilization failure.

Although intracytoplasmic sperm injection (ICSI) is a way to deal with in vitro fertilization failure, 3% of couples still experience repeated fertilization failure after attempted ICSI, despite having sperm within normal parameters. These patients are a challenging group whose sperm cannot fertilize the egg during ICSI. Unfortunately, no test can predict the risk of fertilization failure. Phospholipase C zeta (PLCζ) and transition nuclear proteins (TNPs) are essential factors for chromatin packaging during sperm maturation. This study aimed to assess PLCζ1 and TNP1 expression in the sperm of patients with fertilization failure and the correlations among the DNA fragmentation index, PLCζ1 and TNP1 gene and protein expression, and the risk of fertilization failure. In this study, 12 infertile couples with low fertilization rates (<25%) and complete failure of fertilization in their prior ICSI cycles despite normal sperm parameters were chosen as the case group. Fifteen individuals who underwent ICSI for the first time served as the control group. After sperm analysis and DNA fragmentation assays, quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Western blot analyses were performed to compare the gene and protein expression of PLCζ and TNP1 in both groups. DNA fragmentation was significantly higher in the fertilization failure group. The qRT-PCR and Western blot results demonstrated significantly lower PLCζ and TNP1 gene and protein expression in these patients than in controls. The present study showed that fertilization failure in normozoospermic men was probably due to deficient DNA packaging and expression of TNP1.

Assisted Oocyte Activation following Intracytoplasmic Sperm Injection: A Sensible Option for Infertile Couples with Severe Teratozoospermia.

The intracytoplasmic sperm injection (ICSI) has significantly improved male factor infertility treatment; however, complete fertilization failure still occurs in 1-5% of ICSI treatment cycles mainly due to oocyte activation failure. It is estimated that around 40-70% of oocyte activation failure is associated with sperm factors after ICSI. Assisted oocyte activation (AOA) as an effective approach to avoid total fertilization failure (TFF) has been proposed following ICSI. In the literature, several procedures have been described to overcome failed oocyte activation. These include mechanical, electrical, or chemical stimuli initiating artificial Ca2+ rises in the cytoplasm of oocytes. AOA in couples with previous failed fertilization and those with globozoospermia has resulted in varying degrees of success. The aim of this review is to examine the available literature on AOA in teratozoospermic men undergoing ICSI-AOA and determine whether the ICSI-AOA should be considered as an adjunct fertility procedure for these patients.

O-310 Browsing the Male Genome to Unravel Its Reproductive Potential

Abstract Study question Can whole genome profiling of sperm DNA be used to identify aspects of ART failure and predict embryo developmental competence? Summary answer Whole genome profiling of sperm DNA identifies germline gene mutations associated with reproductive failure and helps characterize subtle male factor infertility. What is known already A routine semen analysis provides limited information on the characteristics of the male gamete and is unable to predict spermatozoa performance in ART. Therefore, ancillary tests may be used to further assess the male gamete’s reproductive potential. Whole exome sequencing (WES) of the male genome carried out on somatic cells has proven to be a powerful technique capable of identifying the genetic roots of infertility. Here, we aim to preferentially detect germline mutations by exclusively sequencing spermatozoal DNA to identify genes related to the different underlying etiologies of reproductive failure. Study design, size, duration Over a 6-year period, 31 consenting couples with negative female infertility workups and normal semen parameters were included in this study. These couples were divided according to whether they reported a successful pregnancy with ART (fertile; n = 10) or not (infertile; n = 21). Sperm aneuploidy assessment by copy number variant (CNV) analysis with WES were carried out on ejaculated spermatozoa. Gene mutation profiles were enlisted and compared between the two patient cohorts to identify genes involved. Participants/materials, setting, methods DNA was extracted and amplified from at least 500 spermatozoa (DNA concentration, 760±486 ng/ul; quality, 1.7±0.1 nm) for CNV analyses by WES. Mutations corresponding to the CNV were then annotated and assessed using the CLC Genomic Server 9.0. Genes were considered duplicated or deleted when their read depth was &amp;gt;1.5 or &amp;lt; 0.5 times the median read depth in the control, respectively. Main results and the role of chance All couples (n = 31) (maternal age, 37.6±3yrs; paternal age, 39.7±5yrs) had adequate semen parameters (concentration, 59.2±30x106/mL, 44.8±18% motility, normal morphology) and normal peripheral karyotypes. The fertile cohort (n = 10) underwent 12 ICSI cycles, achieving an 82.6% (57/69) fertilization rate with 10/12 (83.3%) cycles resulting in live births. The infertile cohort (n = 21) underwent 25 ICSI cycles, achieving a 68.4% (91/133) fertilization rate and 6/14 (42.9%) clinical pregnancies, all resulting in pregnancy loss. CNV analysis indicated lower sperm aneuploidy in the fertile (4.0% vs. 8.4%) cohort (P &amp;lt; 0.00001). In both cohorts, mutations associated with sperm–egg fusion (ADAM3A) and acrosomal development (SPACA1, SPATA16) were identified, justifying ICSI utilization. The infertile cohort included complete fertilization failure, poor early embryo development, implantation failure, or pregnancy loss. Couples with complete fertilization failure (n = 4) had gene deletions (PLCZ1, PIWIL1, ADAM15) indicating sperm-related oocyte-activating deficiency. Those with poor early embryo development (n = 5) had mutations essential for centrosome integrity (HAUS1) and spindle/microtubular stabilization (KIF4A, XRN1). Couples who failed to achieve pregnancy (n = 7) had mutations commonly implicated in embryonic implantation (IL9R) and microtubule/centrosomal integrity (MAP1S). Those with pregnancy losses (n = 5) displayed mutations related to trophoblast development (NLRP7), cell cycle regulation (MARK4, TRIP13, DAB2IP, KIF1C), and a gene linked to recurrent miscarriage (TP53). Limitations, reasons for caution Using WES, we were able to identify germline mutations that appear to be involved in various aspects of human reproduction. These findings are new and should be validated in a larger study population. Moreover, although we attempted to control for maternal age, we still cannot exclude confounding female factors. Wider implications of the findings Evaluating the sperm genome can help identify elusive genetic factors associated with reproductive competence and help guide treatment options for couples unable to conceive who undergo ART. Therefore, screening spermatozoal DNA may serve as an additional tool in precision medicine to identify and treat subtle male factor infertility. Trial registration number N/A

O-044 ICSI in the lab: from vintage to AI

Abstract With the advent of in vitro fertilization (IVF) by Patrick Steptoe and Bob Edwards in the late 70s, the first conception outside of the human body resulted in the birth of Louise Brown. Although a terrific success, limitations of IVF surfaced, represented by the unexpected complete fertilization failure with suboptimal or dysfunctional spermatozoa. This prompted curiosity toward individual spermatozoa for a deeper understanding of its role aimed at enhancing the interaction between complementary gametes. Techniques were designed to manipulate the oocytes, such as stripping, partially digesting, or cracking the zona pellucida (ZP). These methods were palliative solutions to overcome fertilization failure and were often plagued by polyspermy. As a result, more direct approaches were implemented to overcome the ZP, such as subzonal injection (SUZI) that although more consistent, was still unable to overcome the shortcomings of dysfunctional spermatozoa. This laid the foundation for the utilization of ICSI that, whilst attempted by some investigators, became popular when Gianpiero Palermo serendipitously inserted one spermatozoon into the ooplasm during SUZI. Consistent fertilization then followed by injecting a cohort of oocytes by ICSI in SUZI cycles, and replacement of these embryos led to 4 pregnancies described in the first clinical ICSI report. To minimize oocyte damage, the procedure was further refined by inducing a deep invagination of the oolemma toward the 9 o’clock position, granting higher chances of post-injection survival. What set apart ICSI from other forms of ART was that any sperm sample, regardless of quality/quantity, would yield fertilization. Indeed, ICSI is the sole insemination method used with epididymal and testicular spermatozoa and has therefore revolutionized fertility treatment of azoospermic men. Indeed, even immotile testicular spermatozoa can still fertilize and yield successful pregnancies, albeit at a lower rate than their motile counterpart. Also, for these semen sources, aggressive sperm immobilization was introduced to enhance sperm membrane permeabilization and grant optimal fertilization results. Furthermore, ICSI has transformed the field of reproductive medicine by assisting other reproductive techniques, such as testing embryos for single gene defects to reduce the occurence of sperm DNA contamination, or overcoming the cryostress-induced changes of the ZP during cryopreservation allowing the oocyte to be fertilized at a higher rate. Oocyte cryopreservation now empowers women in their reproductive age to ordain their childbearing future. ICSI has proven to be the ultimate technique to overcome male infertility and has broadened its indication by yielding consistent fertilization and successful pregnancies in most circumstances, ensuring that men have the chance of fathering their own progeny. To date, ICSI is applied in several countries, and in some, is performed as the preferred/sole insemination method contributing to the birth of millions of babies worldwide. Thus far, no concerning differences have been seen in the health of ICSI versus standard IVF offspring, or even naturally conceived. In fact, it has been currently established that young adults of both genders born through ICSI retain their reproductive health. Despite its growing popularity, ICSI does not always succeed but still provides an invaluable platform to deepen our knowledge of gamete biology and helps to investigate/overcome some of the most severe and persistent forms of infertility. For example, combined with assisted gamete treatment, ICSI allows couples plagued by sperm-bound oocyte-activation-deficiency to achieve pregnancy. The need to increase access and curtail costs of reproductive care has led to the testing of automation in ART. This is also occurring with ICSI and to date, different automated modules have been proposed for oocyte denudation, sperm tracking, and robotic ICSI. Concurrently, there has been an interest in experimenting with artificial intelligence in the IVF laboratory to minimize human shortcomings and ensure that the best spermatozoon is chosen.

Infertility and Intracytoplasmic Sperm Injection (ICSI)

Infertility is generally defined as a Time to pregnancy (TTP) of longer than 12 months among couples who engage in unprotected intercourse in the fertile days of the menstrual cycle, any specific threshold is arbitrary. The prevalence of infertility differs greatly from one country to another, being 15% globally, &gt;30% in some developing countries, and 17-28% in industrialized countries. The term ‘implantation failure’ can be used to describe both patients who have never shown quantifiable signs of implantation such as increased levels of hCG, and those who have increased hCG production without later ultrasound evidence of a gestational sac. Intracytoplasmic sperm injection (ICSI) is a form of assisted reproductive technology in which a single sperm is injected into the cytoplasm of an egg in order to fertilize it. Complete fertilization failure following ICSI is an uncommon occurrence (1–3 percent), although it does occur even when spermatozoa appear to be normal. Furthermore, in some individuals, low to moderate fertilization (30 percent) has been reported in repeated ICSI cycles. Fertilization failure with ICSI is not the same as it is with traditional IVF technique. 60–90 percent of oocytes which showed a fertilization failure in traditional IVF are devoid of sperm nuclei, assuming that sperm ejection or penetration failure is the most common reason for the failure in fertilization process.

O-120 Unravelling reproductive failure by scrutinizing the male germline code

Abstract Study question Can whole exome sequencing (WES) of spermatozoal DNA provide insight into understanding the different steps that lead to inability of a couple to reproduce? Summary answer The identification of germline mutations can clarify different aspects of reproductive failure in couples with unexplained infertility. What is known already The limitation of a routine semen analysis in evaluating sperm characteristics, even according to the most stringent criteria, lies in its inability to provide substantial information on spermatozoa performance in ART. As a result, ancillary tests are being used to further assess the male gamete’s reproductive potential. More recently, WES of the male genome, carried out on somatic cells, has become a powerful technique that can potentially shed light on the genetic causes of infertility. Here, we aim to preferentially detect germline mutations by sequencing spermatozoal DNA to pinpoint genes related to different underlying etiologies for reproductive failure. Study design, size, duration In a 5-year period, 25 couples subdivided according to their ICSI outcomes were included in this study. Sperm aneuploidy assessment by fluorescent in situ hybridization (FISH) and copy number variant (CNV) analysis by WES were carried out on ejaculated specimens from consenting male partners. Following CNV analysis, gene mutation profiles were compared between the fertile (n = 10) and infertile cohorts (n = 15), as well as in relation to the reasons for reproductive failure. Participants/materials, setting, methods FISH was performed on at least 1,000 sperm cells with a threshold of &amp;gt; 1.6%. DNA was extracted and amplified from at least 500 spermatozoa (DNA concentration, 605±137 ng/ul; quality, 1.7±0.1 nm) for CNV analysis by WES. Mutations corresponding to the CNV were annotated and assessed using the CLC Genomic Server 9.0. Genes were considered duplicated or deleted when their read depth was &amp;gt;1.5 or &amp;lt; 0.5 times the median read depth in the control. Main results and the role of chance Couples (n = 25) (maternal age, 38.6±3yrs; paternal age, 39.7±5yrs) had normal somatic karyotypes with normal semen parameters (59.2±30x106/mL concentration, 44.8±18% motility) by WHO standards. The fertile (n = 10) cohort underwent 12 ICSI cycles, achieving an 82.6% (57/69) fertilization rate and 10/12 (83.3%) term pregnancies. The infertile cohort (n = 15) underwent 21 ICSI cycles, achieving a 66% (62/84) fertilization rate and 5/17 (29.4%) clinical pregnancies, all resulting in pregnancy loss. Sperm aneuploidy was consistently higher in the infertile (8.4%) versus fertile (4.0%) cohort (P&amp;lt;0.00001), as observed by FISH and DNA sequencing. For both cohorts, WES detected deletions responsible for sperm–egg fusion (ADAM3A) and acrosomal development (SPACA, SPATA), explaining the necessity for ICSI in these couples. The infertile cohort was characterized by 4 reasons for cycle failure: complete fertilization failure, poor embryo development, implantation failure, and pregnancy loss. Couples with complete fertilization failure (n = 4) had deletions (PLCZ1, PIWIL1) indicating a sperm-related oocyte-activating deficiency. Those with poor embryo development (n = 5) had mutations (HAUS1, KIF4A, XRN1) essential for centrosome integrity and spindle/microtubular stabilization. Couples who did not achieve pregnancy (n = 7) had a mutation (IL9R) in common related to cytokine constituents in the implantation pathway. Those with pregnancy losses (n = 5) had mutations (NLRP7, TP53) on post-implantation genes. Limitations, reasons for caution Several germline mutations, related to the different reasons for these couples’ reproductive failure, were identified. Although intriguing, these findings are still new and need to be validated in a larger study population. In addition, while maternal age was controlled for, we cannot definitively exclude other confounding female factors. Wider implications of the findings Additional screening methods for infertile couples, particularly those with unexplained infertility, can be used to clarify elusive factors underlying their reproductive ability. A genetic screening of spermatozoal DNA may therefore be considered a potential tool in precision medicine for the treatment of subtle male factor infertility. Trial registration number n/a

O-090 Correcting a PLCζ mutation in the human germ line to overcome hereditary infertility

Abstract Study question Can clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 gene editing result in the correction of a single base pair substitution that causes male infertility? Summary answer CRISPR/Cas9 administration during intracytoplasmic sperm injection (ICSI) leads to correction attempts of mutant phospholipase C zeta (PLCζ), howeverc loss-of-heterozygosity (LOH). What is known already Failed fertilization after ICSI can be caused by mutations in the sperm-related oocyte factor PLCζ which can be overcome by assisted oocyte activation (AOA). In this way, children may inherit the infertility-causing mutation. Mutation transmission can be overcome through CRISPR/Cas9 delivery during ICSI. In previous studies using CRISPR/Cas9 in the human germline for mutation correction, loss-of-heterozygosity (LOH, loss of the allele of one of the parents) was observed. Two different explanations were given, namely partial or complete paternal chromosomal loss or the correction of the mutation by using the maternal wild-type allele instead of the exogeneous supplied repair template. Study design, size, duration We injected a gRNA-Cas9 protein complex to target the PLCζ mutant allele, a repair template harboring the desired nucleotide substitution and an additional synonymous variant to track template usage, together with patient’s sperm. To overcome fertilization failure, AOA was applied during ICSI. After a culture period of maximal 6 days the embryos were collected. At day 3, some embryos were dissociated in individual blastomeres. The extracted DNA was analyzed through different genetic sequencing techniques. Participants/materials, setting, methods Donated sperm of a patient experiencing complete fertilization failure after routine ICSI, harboring a heterozygous base pair substitution in PLCZ1 (c.136-1G&amp;gt;C), was utilized. Sperm was injected in donated in vitro matured oocytes or in vivo matured oocytes containing clusters of smooth endoplasmic reticulum. Next-generation sequencing was used to assess correction potential. Short tandem repeat (STR) and single nucleotide polymorphism (SNP) assays were used to determine whether the sperm contained the mutation and to evaluate LOH. Main results and the role of chance CRISPR/Cas9 injections had no significant impact (p &amp;gt; 0.05) on embryonic development. Due to the heterozygous nature of the mutation, 47% (27/58) of the embryos originated from mutated sperm injection. The CRISPR components showed a high specificity with absence of insertions/deletions in 97% of the embryos originating from wild-type sperm (n = 31). Embryos originating from mutant sperm (n = 27) fall into three categories:(1) 22% showed the untargeted mutant allele, (2) 52% showed additional mutagenesis and (3) 26% showed the wild-type allele, which could be explained by correction. Mosaicism, defined as various editing events, was present in 17% (1), 21% (2) and 71% (3) of the embryos. The low occurrence of the synonymous variant, incorporated in the repair template, suggests that the template is not used during correction attempts. In only 29% (2/7) and 14% (1/7) of the ‘corrected embryos’, respectively long (&amp;gt;18Mb) or medium width LOH (4Mb) was observed through STR analysis. SNP analysis in closer proximity showed in 71% (5/7) of the embryos LOH, even in the absence of LOH through STR, suggesting also the occurrence of short width LOH. These results will be studied in more detail before definitive conclusions can be made. Chromosomal LOH will be studied by ddRADseq. Limitations, reasons for caution The occurrence of mosaicism and LOH might complicate the use of traditional CRISPR/Cas9 in human embryos and should be studied in detail to draw definite conclusions on its potential future use. To this end, genomic data have been produced from both individual blastomeres and whole-embryos which will be further analyzed. Wider implications of the findings Our findings demonstrate caution to use CRISPR/Cas9 to correct mutations in the germ line. They seem to contradict other reports that show predominant lack of mosaicism and presence of long width LOH. A deeper evaluation will be undertaken to define the length and type of LOH in this study. Trial registration number Not Applicable

Karyotypic abnormalities and Y chromosome microdeletions: How do these impact in vitro fertilization outcomes, and how common are they in the modern in vitro fertilization practice?

ObjectiveTo examine the outcomes of in vitro fertilization with intracytoplasmic sperm injection (IVF-ICSI) in couples in whom the male partner has a karyotypic abnormality or Y chromosome microdeletion (YCM).DesignRetrospective cohort.SettingSingle infertility center.Patient(s)Couples treated with IVF-ICSI from January 2014 to April 2019 with male factor infertility, sperm concentration of <5 × 106 sperm/mL, and results for karyotype and/or YCM panel.Intervention(s)In vitro fertilization with intracytoplasmic sperm injection.Main Outcome Measure(s)In couples in whom the male partner had a karyotypic abnormality or YCM: live birth rate/ongoing pregnancy rate, lack of partner sperm for fertilization, complete fertilization failure, cycle cancellation, and no embryos for transfer. The prevalence of karyotypic abnormalities and YCMs in the IVF population was calculated.Result(s)The live birth rate/ongoing pregnancy rate for those using partner sperm was 51.4% per transfer. However, 8.5% of cycles that intended to use partner sperm and 22.2% of cycles that intended to use surgically extracted partner sperm had no sperm available. Of cycles that created embryos with partner sperm, 12.5% had no embryo to transfer. The prevalence of karyotypic abnormalities was similar to previous reports (6.0%), while that of YCMs was lower (4.4%). Azoospermia factor a and b mutations were not represented in this population.Conclusion(s)It is reasonable to attempt IVF-ICSI with partner sperm in patients with genetic causes of male infertility. Patients should be counseled regarding the possibility of no sperm being available from the male partner, poor/failed fertilization, and genetic implications for potential offspring. Contingency plans, including IVF with donor sperm backup or oocyte cryopreservation, need to be made for these scenarios.

Identification of factors related to fertilization failure in in vitro fertilization-embryo transfer.

To investigate the possible factors relevant to fertilization failure in in vitro fertilization-embryo transfer (IVF-ET). The medical records of 4 205 infertile patients undergoing IVF-ET treatment at the Reproductive Medicine Center, Xiangya Hospital, Central South University from January 2016 to December 2017 were collected. The patients were divided into a complete fertilization failure group, a low fertilization rate group, and a control group based on fertilization rate. We examined the associations among the 3 groups in terms of female age, duration of infertility, duration of stimulation, gonadotropin (Gn) dosage, follicle-stimulating hormone (FSH) dosage, and total number of retrieved oocytes. According to theincidence factors, the patients were divided into a single female factor group, a single male factor group and a unisex factor group, and the correlation analysis of incidence factor among the 3 groups was performed. The patients were divided into a primary infertility and a secondary infertility in accordance with the type of infertility. We analyzed the correlation of infertility type among the three groups. Risk factors for complete fertilization failure and low fertilization rate in IVF-ET were obtained by stepwise multiple linear regression analysis. Primary infertility, long infertility duration, total number of retrieved oocytes, and unisex factor were associated with completefertilization failure and low fertilization rate in IVF-ET (P<0.05), but female age, duration of stimulation, FSH dosage as well as Gn dosage were not correlated with complete fertilization failure and low fertilization rate in IVF-ET (P>0.05). Stepwise multiple linear regression analysis showed that the incidence factor, type of infertility, and infertility duration were independent influential factors for complete fertilization failure and low fertilization rate. Complete fertilization failure and low fertilization rate in IVF-ET are related to duration of infertility, total number of retrieved oocytes, cause of onset, and type of infertility, but they are not relevant to female age, duration of stimulation, and Gn and FSH dosage.

Identification and treatment of men with phospholipase Cζ–defective spermatozoa

To identify and treat the gamete responsible for complete fertilization failure with intracytoplasmic sperm injection (ICSI) using a newly proposed assisted gamete treatment (AGT). Prospective cohort study. Center for reproductive medicine. One-hundred and fourteen couples with an adequate number of spermatozoa for ICSI and a fertilization rate of ≤10%, after controlling for maternal age. Couples with an oocyte-related oocyte activation deficiency (OAD) underwent a subsequent cycle with a modified superovulation protocol; couples with sperm-related OAD had an additional genetic and epigenetic assessment to identify mutations and expression levels of the corresponding genes. Treatment cycle outcome for couples undergoing ICSI with either a modified superovulation protocol or AGT compared with their historical cycle. A total of 114 couples matched the inclusion criteria, representing approximately 1.3% of the total ICSI cycles performed at our center, with age-matched controls. Fifty-two couples were confirmed negative for sperm-related OAD by the phospholipase Cζ (PLCζ) assay, indicating oocyte-related factors in their failed fertilization cycles. Couples were treated by one of two AGT protocols, AGT-initial or AGT-revised, in a subsequent attempt that was compared with their historical cycle. Subsequent ICSI cycles with a tailored superovulation protocol yielded significantly higher fertilization (59.0% vs. 2.1%) and clinical pregnancy (28.6% vs. 0) rates. In 24 couples (mean ± standard deviation: maternal age, 35.6 ± 5 years; paternal age, 39.8 ± 6 years) sperm-related OAD was confirmed; in four men, a deletion on the PLCZ1 gene was identified. Additional mutations were also identified of genes supporting spermiogenesis and embryo development (PIWIL1, BSX, NLRP5) and gene deletions confirming a complete absence of the subacrosomal perinuclear theca (PICK1, SPATA16, DPY19L). Subsequent AGT treatment provided higher fertilization (42.1%) and clinical pregnancy (36% vs. 0%) rates for couples with a history of impaired (9.1%) fertilization. A comparison of the two AGT protocols, AGT-initial or AGT-revised, revealed that the latter yielded even more favorable fertilization (37.6% vs. 45.9%) and clinical pregnancy (21.1% vs. 83.3%) rates. In couples with an oocyte-related OAD, tailoring the superovulation protocol resulted in successful fertilization, term pregnancies, and deliveries. In couples with a sperm-related OAD as determined by PLCζ assay, mouse oocyte activation test, and the assessment of gene mutations and function, AGT was successful. The AGT-revised protocol yielded an even higher fertilization rate than the AGT-initial protocol, resulting in the birth of healthy offspring in all couples who achieved a clinical pregnancy.

WEE2 Mutations as a Cause of Complete Fertilization Failure (CFF) When it is the Female Factor Responsible for CFF- A Short Communication

WEE2 Mutations as a Cause of Complete Fertilization Failure (CFF) When it is the Female Factor Responsible for CFF- A Short Communication

Development of ICSI.

The first conception outside of the human body that led to the birth of Louise Brown was a tremendous accomplishment, which opened the door to the utilization of assisted reproductive techniques globally. This brought the understanding that accomplishing life in a dish required several steps, the most obvious being the timing and characteristics of fertilization. It soon became obvious in the 1980s that the most disappointing phenomenon was unexpected and complete fertilization failure. Among the approaches that were attempted to treat male factor infertility, ICSI surfaced as the technique that brought the ratio of the gametes to 1:1 and was also able to grant consistent fertilization and a higher pregnancy rate. ICSI has now been implemented for a quarter of a century, proving itself as the ultimate technique utilizing ejaculated spermatozoa independent of the semen parameters and is the sole insemination method to be used with surgically retrieved spermatozoa. There are currently various indications for ICSI that are widely adopted, rendering it the most popular insemination method worldwide. The reliability of ICSI ensures its employment in upcoming techniques involving in vitro spermatogenesis and neogametogenesis.

Fertilization failure and gamete health: Is there a link?

Fertilization is a hallmark event of sexual reproduction marked by the fusion of male and female gamete to form zygote. It is a highly complex, yet a robust process that is intricately regulated by various signalling molecules. A healthy fertilization is determined by the quality of zygote which is contingent on the health of egg and sperm. The relationship between infertility and gametic health can be reciprocal. On one hand gametogenesis has to be dynamic and unremitting to sustain the reproductive health, while on the other hand it has to be error free for proper embryonic development. Complex cellular interactions make gametogenesis highly vulnerable to extrinsic as well as intrinsic intrusions. Molecular disparities during these phases may result in complete fertilization failure. Present review provides an overview of the regulation of gametogenesis, determinants of healthy gamete, players at fertilization window and what may go wrong during the development of zygote to embryo leading to implantation failure. We have outlined different 'windows' of vulnerability during gametogenesis supported by evidences affecting the fertility potential of both the partners.

Differential effects of short co-incubation of gametes and early removal of cumulus cells in patients with different fertilizing capabilities

The objective of this retrospective study was to evaluate the embryological and clinical outcomes of short co-incubation of gametes and early removal of cumulus cells (SCGERCC) in patients with good IVF capability and those with complete fertilization failure treated by rescue intracytoplasmic sperm injection (ICSI). The study included 257 couples with >60% fertilization rate (SCGERCC group) in the SCGERCC cycle, 72 couples with complete fertilization failure in the SCGERCC cycle given early rescue ICSI treatment (early rescue group), and 219 couples who underwent IVF cycles with overnight co-incubation of gametes with >60% fertilization rate (traditional IVF group). The results showed that the SCGERCC group had a higher multi-pronuclei rate (13.34%, P < 0.001) than the early rescue ICSI (5.15%) and traditional IVF (6.15%) groups. The good quality embryo rate was higher in the SCGERCC group, but implantation, clinical pregnancy and live-birth rates (37.21%, 36.92% and 38.20% for SCGERCC, early rescue and traditional IVF groups, respectively) were comparable in all three groups. The study indicated that SCGERCC followed by rescue ICSI helped couples with initial complete fertilization failure attain clinical outcomes comparable with the other two groups, but it significantly increased the multi-pronuclei rate in couples with good fertilizing capabilities.

The role of in-vivo and in-vitro maturation time on ooplasmic dysmaturity

This study investigates whether the timing of in-vivo and in-vitro maturation influences ooplasmic dysmaturity. This is a retrospective comparison of intracytoplasmic sperm injection (ICSI) cycles (index cycles) complicated by complete fertilization failure (CFF) to cycles with successful fertilization in the same patient. The cycle following the index cycle was modified intentionally to increase fertilization. The times between human chorionic gonadotrophin (HCG) trigger and oocyte retrieval, HCG trigger and removal of cumulus cells, and HCG trigger and sperm injection were recorded. Fifteen patients were included. Compared with successful fertilization cycles, index (CFF) cycles showed a shorter time interval between HCG trigger and oocyte retrieval (2029.0 ± 16 versus 2195.0 ± 10 min; P < 0.001), HCG trigger and removal of cumulus cells (2201.4 ± 15 versus 2309.0 ± 23 min; P < 0.001) and oocyte retrieval and removal of cumulus cells (114.0 ± 13 versus 171.8 ± 15 min; P < 0.001). The interval between HCG trigger and ICSI was comparable between groups. Findings reveal novel patterns in time intervals between HCG trigger, oocyte retrieval, removal of cumulus cells and ICSI. Thus, modulating time intervals between HCG trigger, oocyte retrieval, removal of cumulus cells and ICSI to grant fertilization seems feasible.

IVF-ICSI Split Insemination Reveals those Cases of Unexplained Infertility Benefitting from ICSI Even when the DNA Fragmentation Index is Reduced to 15% or Even 5%

IVF-ICSI Split Insemination Reveals those Cases of Unexplained Infertility Benefitting from ICSI Even when the DNA Fragmentation Index is Reduced to 15% or Even 5% Purpose The aim of the study was to assess the fertilization rate (FR) of randomized sibling oocytes inseminated by conventional IVF or ICSI in couples with unexplained infertility. Methods The 16-month study was conducted at an established private IVF facility. Oocytes recovered from couples with normal semen parameters and normal DNA fragmentation index (DFI; <30%), were randomly allocated to IVF or ICSI and the FR (2PN/MII) was assessed. Pregnancy outcome following embryo transfers were analyzed with regards to either IVF-embryo vs. ICSI-embryo, and in relation to DFI levels. Results Of 585 oocytes retrieved from 38 patients, 463 were mature (MII). The ICSI group generated a significantly higher number of 2PN embryos with a mean FR of 83.4% vs. 67.6% (p<0.05). There were no cases of complete fertilization failure (CFF) in the ICSI group, but there were 7.9% in the IVF group. The significant difference of FR was observed only when the DFI level was ≥ 15% and if such cutoff was applied, the CFF cases would be reduced to 2.6%. Of the 30 patients who had fresh embryo transfers performed, the ICSI group showed a higher pregnancy rate (69.2% vs. 58.8%; N.S.) with a significantly higher mean DFI value in the non-pregnant group (p<0.05). Conclusions IVF-ICSI split insemination can reveal those cases which will benefit from ICSI even where semen parameters and DFI are normal; however if the DFI is reduced to a 15% cut-off level, the rate of CFF will be minimized, but not completely excluded, even at 5%..

Homozygous mutation of PLCZ1 leads to defective human oocyte activation and infertility that is not rescued by the WW-binding protein PAWP.

In mammals, sperm-oocyte fusion initiates Ca(2+) oscillations leading to a series of events called oocyte activation, which is the first stage of embryo development. Ca(2+) signaling is elicited by the delivery of an oocyte-activating factor by the sperm. A sperm-specific phospholipase C (PLCZ1) has emerged as the likely candidate to induce oocyte activation. Recently, PAWP, a sperm-born tryptophan domain-binding protein coded by WBP2NL, was proposed to serve the same purpose. Here, we studied two infertile brothers exhibiting normal sperm morphology but complete fertilization failure after intracytoplasmic sperm injection. Whole exomic sequencing evidenced a missense homozygous mutation in PLCZ1, c.1465A>T; p.Ile489Phe, converting Ile 489 into Phe. We showed the mutation is deleterious, leading to the absence of the protein in sperm, mislocalization of the protein when injected in mouse GV and MII oocytes, highly abnormal Ca(2+) transients and early embryonic arrest. Altogether these alterations are consistent with our patients' sperm inability to induce oocyte activation and initiate embryo development. In contrast, no deleterious variants were identified in WBP2NL and PAWP presented normal expression and localization. Overall we demonstrate in humans, the absence of PLCZ1 alone is sufficient to prevent oocyte activation irrespective of the presence of PAWP. Additionally, it is the first mutation located in the C2 domain of PLCZ1, a domain involved in targeting proteins to cell membranes. This opens the door to structure-function studies to identify the conserved amino acids of the C2 domain that regulate the targeting of PLCZ1 and its selectivity for its lipid substrate(s).

Oocyte activation deficiency: a role for an oocyte contribution?

Infertility affects between 10 and 16% of couples worldwide. Twenty to 30% of cases of infertility are due to a male factor, 20-35% to a female factor, and 25-40% are due to both male and female factors. In ∼10-25% of cases, the precise underlying cause remains unclear. IVF or ICSI followed by embryo transfer can be very appropriate treatment options in cases of female tubal damage, ovulatory failure or male-factor infertility. While the use of IVF has been reported to be suitable for many infertile couples, normal IVF cycles can fail in some cases. While ICSI can represent a powerful alternative in cases of IVF failure, complete fertilization failure can still occur in 1-5% of ICSI cycles. This can be due to a variety of factors and while commonly attributed to deficiency of sperm factors, it is very likely that abnormalities in crucial oocyte factors could also play a key role. A critical literature review using PubMed was performed between April 2014 and July 2015 targeting studies concerning sperm and oocyte factors that could account for oocyte activation deficiency, and including studies of in vitro oocyte maturation in human oocytes, and animal models. Accumulating evidence indicates that phospholipase C zeta (PLCζ) is the sperm oocyte activation factor, although recent studies claim that another sperm protein known as post-acrosomal WWP-binding domain protein could also play a significant role in the activation of oocytes. The present review discusses our current understanding of these two proteins but emphasizes that defects in the molecular machinery within the oocyte that interacts with such sperm proteins may also represent an underlying cause of fertilization failure and infertility, especially in cases where there is no obvious indication for sperm deficiency. Abnormalities in such mechanisms are highly likely to exert influence over the pulsatile release of calcium within the ooplasm, the critical signal that controls oocyte activation events. These molecular targets within the oocyte are rarely, if ever, considered clinically. We therefore recommend that future diagnostic assays should be developed to consider the inositol triphosphate receptor, protein kinase C, proteins associated with stored operated calcium entry calcium/calmodulin-dependent protein kinase II and mitogen-activated protein kinase. Development of such assays would represent a significant step forward in the diagnosis of oocyte activation deficiency and may identify a series of potential therapeutic targets. The present review provides a general overview of how a combination of sperm and oocyte factors can underlie oocyte activation deficiency, but pays particular attention to the less appreciated role of the oocyte. Enhanced research within this realm is much warranted and may establish new approaches for the diagnosis and treatment of infertility.