Reproductive outcome in globozoospermic men: update and prospects

Kinesin-14 KIFC1 promotes acrosome formation and chromatin maturation during mouse spermiogenesis

KIFC1, a member of kinesin-14 subfamily motors, is essential for meiotic cell division and acrosome formation during spermatogenesis. However, the functions of KIFC1 in the formation and maintenance of the acrosome in male germ cells remain to be elucidated. In this study, we report the structural deformities of acrosomes in the in vivo KIFC1 inhibition mouse models. The proacrosomal vesicles diffuse into the cytoplasm and form atypical acrosomal granules. This phenotype is consistent with globozoospermia patients and probably results from the failure of the Golgi-derived vesicle trafficking and actin filament organization. Moreover, the multinucleated and undifferentiated spermatogenic cells in the epidydimal lumen after KIFC1 inhibition reveal the specific roles of KIFC1 in regulating post-meiotic maturation. Overall, our results uncover KIFC1 as an essential regulator in the trafficking, fusion and maturation of acrosomal vesicles during spermiogenesis.

The use of ICSI in ART: evidence for practice

This article reviews the evidence regarding the safety and efficacy of intra-cytoplasmic sperm injection (ICSI). It provides evidence-based clinical and laboratory guidelines and recommendations for use of ICSI within an assisted reproductive technology (ART) service. The guidelines address the evidence for the use of ICSI rather than conventional IVF (cIVF); the use of ART techniques supplementary to ICSI; and risks associated with ICSI. This article is not intended to be the only approved standard of practice or to dictate an exclusive course of treatment. Other plans of management may be appropriate, taking into account the needs and medical history of the patient, available resources, and institutional or clinical practice limitations.

Awareness and reporting of globozoospermia among in vitro fertilization and andrology laboratories: A national survey

Globozoospermia (GZ) is a rare disorder found in less than 0.1% of infertile men in which spermatozoa lack acrosomes necessary for penetration of an oocyte. While methods have been demonstrated to allow globozoospermic men to achieve a viable pregnancy with their partner, the Wold Health Organization considers identifying and reporting GZ on semen analysis to be 'important'. Our study aims to determine if and to what extent in vitro fertilization (IVF) laboratories nationwide recognize and report GZ on semen analysis reports. We constructed an IRB-approved survey sent nationwide to IVF and andrology clinic laboratory directors listed by the Society for Assisted Reproductive Technology and/or the American Society for Reproductive Medicine. Results from the survey were de-identified for analysis. A total of 490 surveys were sent with a response rate of 10% (n = 51). Most respondents (66%) practiced in a private, rather than academic, setting. A majority of respondents were confident in their technicians' knowledge of GZ (86%) and ability to identify it on a sample (94%). However, only half of respondents noted a space to report the concern for GZ to the ordering physician, and 25% of respondents did not feel their clinic was able to identify patients where there is a concern for GZ. Similarly, 84% of respondents did not report a percent of acrosome-deficient sperm. Less than half of respondents reported that their clinic has previously diagnosed GZ. Though the majority of respondents felt that their laboratory technicians would be able to identify GZ, a significant minority felt that their clinic did not have means to be able to report concern for GZ. This may be due to the absence of a proper channel to report a concern for GZ, a lack of knowledge about the condition, or failure to distinguish GZ from a broader reported percentage of morphologically abnormal sperm. Given evidence that the diagnosis of GZ may be under-reported in the United States, there should be a national standard for laboratory technicians to be trained to recognize GZ and be able to report their suspicion to the ordering clinician.

Development a nomogram to predict fertilisation rate of infertile males with borderline semen by using semen parameters combined with AMH and INHB

The sperm quality of some males is in a critical state, making it hard for clinicians to choose the suitable fertilisation methods. This study aimed to develop an intelligent nomogram for predicting fertilisation rate of infertile males with borderline semen. 160 males underwent in vitro fertilisation (IVF), 58 of whom received rescue ICSI (R‐ICSI) due to fertilisation failure (fertilisation rate of IVF ≤30%). A least absolute shrinkage and selection operator (LASSO) regression analysis identified sperm concentration, progressively motile spermatozoa (PMS), seminal plasma anti‐Müllerian hormone (spAMH), seminal plasma inhibin (spINHB), serum AMH (serAMH) and serum INHB (serINHB) as significant predictors. The nomogram was plotted by multivariable logistic regression. This nomogram‐illustrated model showed good discrimination, calibration and clinical value. The area under the receiver operating characteristic curve (AUC) of the nomogram was 0.762 (p < .001). Calibration curve and Hosmer–Lemeshow test (p = .5261) showed good consistency between the predictions of the nomogram and the actual observations, and decision curve analysis showed that the nomogram was clinically useful. This nomogram may be useful in predicting fertilisation rate, mainly focused on new biomarkers, INHB and AMH. It could assist clinicians and laboratory technicians select appropriate fertilisation methods (IVF or ICSI) for male patients with borderline semen.

Molecular Analysis of DPY19L2, PICK1 and SPATA16 in Italian Unrelated Globozoospermic Men

This study aims to evaluate genetic contribution and sperm DNA fragmentation (SDF) in a cohort of 18 unrelated globozoospermic Italian men (Group G). Semen samples were assessed according to the WHO 2010 Laboratory Manual and compared with 31 fertile controls. We focused our genetic analysis on the exons of the main globozoospermia-associated genes, performing qualitative PCR to assess deletion of DPY19L2 and sequencing to detect mutations of SPATA16 and PICK1. SDF was evaluated using the TUNEL assay. In Group G, 10 patients had a complete form of globozoospermia, whereas 8 patients had a partial form. Molecular analysis revealed deletion of DPY19L2 in six of the patients, all of them with complete globozoospermia, while no mutations were found in the examined exons of PICK1 and SPATA16. TUNEL analysis showed a higher SDF% in Group G. Our findings confirm DPY19L2 defects as the most frequent genetic alteration in Italian patients contributing to globozoospermic phenotypes. Furthermore, spermatozoa with acrosomal defects could also display high levels of SDF as a possible consequence of abnormally remodeled chromatin. The possible effect on offspring of chromatin structure abnormalities and altered DNA integrity should be carefully evaluated by clinicians, especially regarding the feasibility and safety of artificial reproductive techniques, which represent the only treatment that allows these patients to conceive.

Canary in the Coal Mine? Male Infertility as a Marker of Overall Health

Male factor infertility is a common problem. Evidence is emerging regarding the spectrum of systemic disease and illness harbored by infertile men who otherwise appear healthy. In this review, we present evidence that infertile men have poor overall health and increased morbidity and mortality, increased rates of both genitourinary and non-genitourinary malignancy, and greater risks of systemic disease. The review also highlights numerous genetic conditions associated with male infertility as well as emerging translational evidence of genitourinary birth defects and their impact on male infertility. Finally, parallels to the overall health of infertile women are presented. This review highlights the importance of a comprehensive health evaluation of men who present for an infertility assessment.

Exome sequencing reveals novel causes as well as new candidate genes for human globozoospermia

STUDY QUESTION

Can exome sequencing identify new genetic causes of globozoospermia?

SUMMARY ANSWER

Exome sequencing in 15 cases of unexplained globozoospermia revealed deleterious mutations in seven new genes, of which two have been validated as causing globozoospermia when knocked out in mouse models.

WHAT IS KNOWN ALREADY

Globozoospermia is a rare form of male infertility characterised by round-headed sperm and malformation of the acrosome. Although pathogenic variants in DPY19L2 and SPATA16 are known causes of globozoospermia and explain up to 70% of all cases, genetic causality remains unexplained in the remaining patients.

STUDY DESIGN, SIZE, DURATION

After pre-screening 16 men for mutations in known globozoospermia genes DPY19L2 and SPATA16, exome sequencing was performed in 15 males with globozoospermia or acrosomal hypoplasia of unknown aetiology.

PARTICIPANTS/MATERIALS, SETTING, METHOD

Targeted next-generation sequencing and Sanger sequencing was performed for all 16 patients to screen for single-nucleotide variants and copy number variations in DPY19L2 and SPATA16. After exclusion of one patient with DPY19L2 mutations, we performed exome sequencing for the 15 remaining subjects. We prioritised recessive and X-linked protein-altering variants with an allele frequency of <0.5% in the population database GnomAD in genes with an enhanced expression in the testis. All identified candidate variants were confirmed in patients and, where possible, in family members using Sanger sequencing. Ultrastructural examination of semen from one of the patients allowed for a precise phenotypic characterisation of abnormal spermatozoa.

MAIN RESULTS AND ROLE OF CHANCE

After prioritisation and validation, we identified possibly causative variants in eight of 15 patients investigated by exome sequencing. The analysis revealed homozygous nonsense mutations in ZPBP and CCDC62 in two unrelated patients, as well as rare missense mutations in C2CD6 (also known as ALS2CR11), CCIN, C7orf61 and DHNA17 and a frameshift mutation in GGN in six other patients. All variants identified through exome sequencing, except for the variants in DNAH17, were located in a region of homozygosity. Familial segregation of the nonsense variant in ZPBP revealed two fertile brothers and the patient’s mother to be heterozygous carriers. Paternal DNA was unavailable. Immunohistochemistry confirmed that ZPBP localises to the acrosome in human spermatozoa. Ultrastructural analysis of spermatozoa in the patient with the C7orf61 mutation revealed a mixture of round heads with no acrosomes (globozoospermia) and ovoid or irregular heads with small acrosomes frequently detached from the sperm head (acrosomal hypoplasia).

LIMITATIONS, REASONS FOR CAUTION

Stringent filtering criteria were used in the exome data analysis which could result in possible pathogenic variants remaining undetected. Additionally, functional follow-up is needed for several candidate genes to confirm the impact of these mutations on normal spermatogenesis.

WIDER IMPLICATIONS OF THE FINDINGS

Our study revealed an important role for mutations in ZPBP and CCDC62 in human globozoospermia as well as five new candidate genes. These findings provide a more comprehensive understanding of the genetics of male infertility and bring us closer to a complete molecular diagnosis for globozoospermia patients which would help to predict the success of reproductive treatments.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by The Netherlands Organisation for Scientific Research (918–15-667); National Health and Medical Research Council of Australia (APP1120356) and the National Council for Scientific Research (CONICET), Argentina, PIP grant 11220120100279CO. The authors have nothing to disclose.

Bi-allelic mutation in Fsip1 impairs acrosome vesicle formation and attenuates flagellogenesis in mice

Fibrous sheath interacting protein 1 (Fsip1) is a cytoskeletal structural protein of the sperm flagellar proteome. A few studies have reported that it plays a vital role in the tumorigenesis and cancer progression. However, little is known about the role of Fsip1 in spermatogenesis and mammalian sperm flagellogenesis. Fsip1 protein showed the highest expression in round spermatids, and was translocated from nucleus to the anterior region of the elongating spermatid head. To investigate its role we constructed homozygous Fsip1 null (Fsip1^−/−) mice. We found that the homozygous Fsip1^−/− mutant mice were infertile, with a low sperm count and impaired motility. Interestingly, a subtle phenotype characterized by abnormal head shape, and flagella deformities was observed in the sperm of Fsip1^−/− mutant mice similar to the partial globozoospermia phenotype. Electron microscopy analysis of Fsip1^−/− sperm revealed abnormal accumulation of mitochondria, disrupted axoneme and retained cytoplasm. Testicular sections showed increased cytoplasmic vacuoles in the elongated spermatid of Fsip1^–/–mice, which indicated an intraflagellar transport (IFT) defect. Using proteomic approaches, we characterized the cellular components and the mechanism underlying this subtle phenotype. Our result indicated that Fsip1^–/–downregulates the formation of acrosomal membrane and vesicles proteins, intraflagellar transport particles B, and sperm flagellum components. Our results suggest that Fsip1 is essential for normal spermiogenesis, and plays an essential role in the acrosome biogenesis and flagellogenesis by attenuating intraflagellar transport proteins.

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Disruption of Fsip1 leads to infertility with partial globozoospermia phenotype.

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Homozygous deletion of Fsip1 alters spermiogenesis.

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Fsip1 Knockout disrupts acrosome vesicle formation.

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Fsip1 motif analysis involves in internal fertilization.

Sperm-oocyte interplay: an overview of spermatozoon's role in oocyte activation and current perspectives in diagnosis and fertility treatment

The fertilizing spermatozoon is a highly specialized cell that selects from millions along the female tract until the oocyte. The paternal components influence the oocyte activation during fertilization and are fundamental for normal embryo development; however, the sperm-oocyte interplay is in a continuous debate. This review aims to analyze the available scientific information related to the role of the male gamete in the oocyte activation during fertilization, the process of the interaction of sperm factors with oocyte machinery, and the implications of any alterations in this interplay, as well as the advances and limitations of the reproductive techniques and diagnostic tests. At present, both PLCζ and PAWP are the main candidates as oocyte activated factors during fertilization. While PLCζ mechanism is via IP₃, how PAWP activates the oocyte still no clear, and these findings are important to study and treat fertilization failure due to oocyte activation, especially when one of the causes is the deficiency of PLCζ in the sperm. However, no diagnostic test has been developed to establish the amount of PLCζ, the protocol to treat this type of pathologies is broad, including treatment with ionophores, sperm selection improvement, and microinjection with PLCζ protein or RNA.

Genetics of teratozoospermia: Back to the head

Spermatozoa are polarized cells with a head and a flagellum joined by the connecting piece. Head integrity is critical for normal sperm function, and head defects consistently lead to male infertility. Abnormalities of the sperm head are among the most severe and characteristic sperm defects. Patients presenting with a monomorphic head sperm defects such as globozoospermia or marcrozoospermia were analyzed permitting to identify several key genes for spermatogenesis such as AURKC and DPY19L2. The study of patients with other specific sperm head defects such as acephalic spermatozoa have also enabled the identification of new infertility genes such as SUN5. Here, we review the genetic causes leading to morphological defects of sperm head. Advances in the genetics of male infertility are necessary to improve the management of infertility and will pave the road towards future strategies of treatments, especially for patients with the most severe phenotype as sperm head defects.

Thoughts on the popularity of ICSI

Purpose

Intracytoplasmic sperm injection (ICSI) is the most widely utilized assisted reproductive technique (ART) worldwide. In this feature, we review the early assisted fertilization attempts that eventually led to the development of ICSI, and discuss its current utilization in cases of male and non-male factor infertility.

Methods

We researched the literature related to the development, indications, and current use of ICSI, such as sperm structural abnormalities, male genetic indications, surgically retrieved sperm, high sperm chromatin fragmentation, oocyte dysmorphism, and preimplantation genetic testing (PGT). We also describe the potential future applications of ICSI.

Results

This review summarizes the early micromanipulation techniques that led to the inception of ICSI. We also explore its current indications, including non-male factor infertility, where its use is more controversial. Finally, we consider the benefits of future advancements in reproductive biology that may incorporate ICSI, such as in vitro spermatogenesis, neogametogenesis, and heritable genome editing.

Conclusion

The versatility, consistency, and reliability of ICSI have made it the most prevalently utilized ART procedure worldwide.

Knockout of serine-rich single-pass membrane protein 1 (Ssmem1) causes globozoospermia and sterility in male mice†

Globozoospermia (sperm with an abnormally round head shape) and asthenozoospermia (defective sperm motility) are known causes of male infertility in human patients. Despite many studies, the molecular details of the globozoospermia etiology are still poorly understood. Serine-rich single-pass membrane protein 1 (Ssmem1) is a conserved testis-specific gene in mammals. In this study, we generated Ssmem1 knockout (KO) mice using the CRISPR/Cas9 system, demonstrated that Ssmem1 is essential for male fertility in mice, and found that SSMEM1 protein is expressed during spermatogenesis but not in mature sperm. The sterility of the Ssmem1 KO (null) mice is associated with globozoospermia and loss of sperm motility. To decipher the mechanism causing the phenotype, we analyzed testes with transmission electron microscopy and discovered that Ssmem1-disrupted spermatids have abnormal localization of Golgi at steps eight and nine of spermatid development. Immunofluorescence analysis with anti-Golgin-97 to label the trans-Golgi network, also showed delayed movement of the Golgi to the spermatid posterior region, which causes failure of sperm head shaping, disorganization of the cell organelles, and entrapped tails in the cytoplasmic droplet. In summary, SSMEM1 is crucial for intracellular Golgi movement to ensure proper spatiotemporal formation of the sperm head that is required for fertilization. These studies and the pathway in which SSMEM1 functions have implications for human male infertility and identifying potential targets for nonhormonal contraception.

Proteomic Research of Molecular Defects in Globozoospermia

Globozoospermia is a form of teratozoospermia characterized by round-headed spermatozoa and lack of acrosome. These spermatozoa cannot penetrate the zona pellucida of the oocyte, resulting in unsuccessful fertilization and infertility. When intracytoplasmic sperm injection is performed, the fertilization rate tends to be low. Until now, the causes of this disorder remain to be elucidated; however, mutations of some genes segregating on an autosomal recessive mode have been associated with this infertile condition. DPY19L2 (dpy-19-like 2 [Caenorhabditis elegans]) codes for a transmembrane protein expressed predominantly in spermatids, with specific localization limited to the internal nuclear membrane. Genetic defects in the DPY19L2 gene have been demonstrated the most frequent genetic cause of globozoospermia; however, intracellular molecular pathways related to its encoded protein are largely unknown. In this issue of Proteomics Clinical Applications, Guo and co-workers investigate the proteome of gloobozoospermic spermatozoa. The authors identified 491 proteins that are differentially expressed in globozoospermia (370 are upregulated and 121 are downregulated in DPY19L2-deficient globozoospermic sperm). Notably, the molecular defects identified by the authors are closely related to biological processes involved in acrosome formation, chromatin composition, sperm-egg binding, and fertilization.

Globozoospermia syndrome: An update

Among the factors involved in male infertility, there is a rare morphology disorder called "globozoospermia" that is classified into total globozoospermia and partial globozoospermia (type I and type II, respectively). This syndrome is primarily characterised by the presence of round-headed spermatozoa with cytoskeleton defects around the nucleus and no acrosome. Current data support the negative correlation between globozoospermia and conventional intracytoplasmic sperm injection (ICSI) outcomes, revealing the need for the management of patients undergoing assisted reproduction technology (ART) through more effective treatment techniques. This review highlights the most important characteristics of globozoospermia such as sperm parameters, DNA/chromatin integrity and sperm DNA fragmentation (SDF), as well as genetic features based on the latest knowledge. Additionally, we looked into current progress on fertilisation potential and possible treatment strategies for patients presenting with globozoospermia.

Proteomic Analysis of Dpy19l2-Deficient Human Globozoospermia Reveals Multiple Molecular Defects

PURPOSE

To investigate the differences in protein expression between Dpy19l2-deficient human globozoospermia and normozoospermia.

EXPERIMENTAL DESIGN

Human sperm samples from three globozoospermic donors with Dpy19l2 deletion and three normal controls are subjected to TMT quantitative technology. SPESP1, HIST1H4A, and LYZL1 are randomly selected for western blotting analysis. GO annotations are performed using the Database for Annotation, Visualization, and Integrated Discovery.

RESULTS

A total of 2567 proteins are identified, of which 2510 proteins are quantified, and 491 are differentially expressed (fold-change > 2), with 370 upregulated and 121 downregulated in globozoospermic patients. The levels of several important proteins, including SPACA 1, IZUMO1, ZPBP1, and PLCZ1, are decreased in globozoospermic sperm. Bioinformatics analysis indicates the Dpy19l2-deficient sperm presented molecular defects in acrosome, chromatin, sperm-egg interaction, and fertilization.

CONCLUSIONS AND CLINICAL RELEVANCE

The present study is the first to analyze total globozoospermia with Dpy19l2 deletion using high-throughput proteomics. This study may provide insights into the mechanism of globozoospermia.

The functional anatomy of the human spermatozoon: relating ultrastructure and function

The Internet, magazine articles, and even biomedical journal articles, are full of cartoons of spermatozoa that bear minimal resemblance to real spermatozoa, especially human spermatozoa, and this had led to many misconceptions about what spermatozoa look like and how they are constituted. This review summarizes the historical and current state of knowledge of mammalian sperm ultrastructure, with particular emphasis on and relevance to human spermatozoa, combining information obtained from a variety of electron microscopic (EM) techniques. Available information on the composition and configuration of the various ultrastructural components of the spermatozoon has been related to their mechanistic purpose and roles in the primary aspects of sperm function and fertilization: motility, hyperactivation, capacitation, the acrosome reaction and sperm-oocyte fusion.

Reduction of truncated Kit Expression in Men with Abnormal Semen Parameters, Globozoospermia and History of Low or Fertilization Failure

Objective

Phospholipase C zeta 1 (PLCζ) is one of the main sperm factor involved in oocyte activation and other factors may assist this factor to induce successful fertilization. Microinjection of recombinant tr-kit, a truncated form of c-kit receptor, into metaphase II-arrested mouse oocytes initiate egg activation. Considering the potential roles of tr- KIT during spermiogenesis and fertilization, we aimed to assess expression of tr-KIT in sperm of men with normal and abnormal parameters and also in infertile men with previous failed fertilization and globozoospermia.

Materials and Methods

This experimental study was conducted from September 2015 to July 2016 on 30 normozoospermic and 20 abnormozoospermic samples for experiment one, and also was carried out on 10 globozoospermic men, 10 men with a history low or failed fertilization and 13 fertile men for experiment two. Semen parameters and sperm DNA fragmentation were assessed according to WHO protocol, and TUNEL assay. Sperm tr- KIT was evaluated by flow cytometry, immunostaining and western blot.

Results

The results show that tr-KIT mainly was detected in post-acrosomal, equatorial and tail regions. Percentage of tr-KIT-positive spermatozoa in abnormozoospermic men was significantly lower than normozoospermic men. Also significant correlations were observed between sperm tr-KIT with sperm count (r=0.8, P<0.001), motility (r=0.31, P=0.03) and abnormal morphology (r=-0.6, P<0.001). Expression of tr-KIT protein was significantly lower in infertile men with low/ failed fertilization and globozoospermia compared to fertile men. The significant correlation was also observed between tr-KIT protein with fertilization rate (r=-0.46, P=0.04). In addition, significant correlations were observed between sperm DNA fragmentation with fertilization rate (r=-0.56, P=0.019) and tr-KIT protein (r=-0.38, P=0.04).

Conclusion

tr-KIT may play a direct or indirect role in fertilization. Therefore, to increase our insight regarding the role of tr-KIT in fertilization further research is warranted.

Treatment of idiopathic oligozoospermia with combined human chorionic gonadotropin/human menopausal gonadotrophin: A randomised, double-blinded, placebo-controlled clinical study

To evaluate whether hCG/hMG therapy has beneficial effects on idiopathic oligozoospermia in Chinese infertility population. The patients were randomly divided into the treatment group receiving hCG/hMG for 3 months and the placebo group receiving placebo for 3 months. Semen and biochemical analysis was performed, and DNA fragmentation as well as spermatid concentration was evaluated. Administration of hCG/hMG for 3 months could significantly improve sperm concentration, rate of forward motile spermatozoa, total motile sperm count, the percentage of sperm with normal morphology and the rate of spontaneous pregnancy in medium- and higher-level inhibin B group respectively. Moreover, in medium- and higher-level inhibin B group, sperm DNA fragmentation index and spermatid concentration were significantly declined respectively at the end of treatment. However, there were no significant differences in lower-level inhibin B group before and after treatment in term of seminal parameters, DNA fragmentation and spermatid concentration. HCG/hMG therapy for 3 months has a beneficial effect on a part of male with idiopathic oligozoospermia, and the efficacy of hCG/hMG therapy is associated with the inhibin B level.

Is there an association between PAWP/WBP2NL sequence, expression, and distribution in sperm cells and fertilization failures in ICSI cycles?

Successful fertilization in mammals depends on the sperm's ability to initiate intracellular Ca²⁺ oscillations in the egg, a phenomenon that is elicited by Sperm-oocyte activating factors (SOAFs), whose quantitative and/or qualitative defect might result in fertilization failure. One such proposed factor is Post-acrosomal WW domain-binding protein (PAWP/WBP2NL), although its ability to activate human oocytes has been questioned and its implication in human fertilization failure remains unknown. Here, we sought to determine if PAWP/WBP2NL expression and distribution in sperm cells associate with low/complete fertilization failure in males participating in intracytoplasmic sperm injection (ICSI) cycles. This prospective study was conducted on eight couples referred for elective ICSI with either the woman's own (n = 4) or a donor eggs (n = 4). Eight sperm donor samples used in ICSI, which resulted in normal fertilization rates, were used as the control group. For each male patient and donor sperm, PAWP/WBP2NL sequence, protein expression, and cellular distribution were analyzed by PCR amplification-sequencing, Western blot, and immunofluorescence, respectively. PAWP/WBP2NL was present in all samples, and no significant differences were detected between patients with fertilization failure and donors in sequence variants or mean protein expression, or in the proportion of PAWP/WBP2NL-positive sperm. In conclusion, no clear association between PAWP/WBP2NL protein expression in sperm and fertilization outcome in ICSI were observed from this cohort.

Expression of sperm PLCζ and clinical outcomes of ICSI-AOA in men affected by globozoospermia due to DPY19L2 deletion

Globozoospermia is characterized by the presence of 100% acrosomeless round-headed spermatozoa in an ejaculate. Failed fertilization after intracytoplasmic sperm injection (ICSI) is commonly reported for globozoospermic couples and can be overcome by artificial oocyte activation (AOA). Phospholipase C zeta (PLCζ) is one of the main sperm factors involved in oocyte activation and its low expression levels mainly account for fertilization failure. Deletion of the DPY19L2 gene is reported as a main genetic cause in over 70% of infertile men with globozoospermia. The current study assesses the expression profile of sperm PLCζ at RNA and protein levels in 32 DPY19L2 deletion-mediated globozoospermic men and reports corresponding clinical outcomes following ICSI with AOA. The expression of PLCζ relative to GAPDH at RNA (0.78 ± 0.16 versus 1.65 ± 0.24; P = 0.02) and protein (0.39 ± 0.12 versus 0.83 ± 0.13; P = 0.01) levels in globozoospermic men with DPY19L2 deletion was significantly lower compared with fertile men (n = 32). Fertilization rate in globozoospermic couples following ICSI-AOA was significantly lower compared with fertile men (53.14 ± 5.13% versus 87.64 ± 2.38%, P < 0.001). However, implantation (26.2%) and pregnancy (53.8%) rates were not jeopardized by DPY19L2 deletion in these couples.

Novel concepts in the aetiology of male reproductive impairment

Infertility is a widespread problem and a male contribution is involved in 20-70% of affected couples. As a man's fertility relies on the quantity and quality of his sperm, semen analysis is generally used as the proxy to estimate fertility or gain insight into the underlying reasons for infertility. Male reproductive impairment might result from factors that affect sperm production, quality, function, or transport. Although in most men the origin of infertility remains unexplained, genetic causes are increasingly being discovered. In this first of two papers in The Lancet Diabetes and Endocrinology Series on male reproductive impairment, we propose a novel, clinically based aetiological construct with a genetic focus, and consider how this might serve as a helpful way to conceptualise a diagnostic algorithm.

Concepts in diagnosis and therapy for male reproductive impairment

An accurate medical history and directed physical examination are essential in diagnosis of male infertility. We review the hormonal assessments and specific genetic analyses that are useful additional tests, and detail other evidence-based examinations that are available to help guide therapeutic strategies. By contrast with female infertility treatments-especially hormonal manipulations to stimulate or enhance oocyte production-spermatogenesis and sperm quality abnormalities are much more difficult to affect positively. In general, a healthy lifestyle can improve sperm quality. A few men have conditions in which evidence-based therapies can increase their chances for natural conception. In this second of two papers in The Lancet Diabetes and Endocrinology Series on male reproductive impairment, we examine the agreements and controversies that surround several of these conditions. When we are not able to cure, correct, or mitigate the cause of conditions such as severe oligozoospermia, non-remedial ductal obstruction, and absence of sperm fertilising ability, assisted reproductive technologies, such as in-vitro fertilisation (IVF) with intracytoplasmic sperm injection (ICSI), can be used as an adjunctive measure to allow for biological paternity. Not considered possible just two decades ago, azoospermia due to testicular failure, including 47,XXY (Klinefelter syndrome), is now treatable in approximately 50% of cases when combining surgical harvesting of testicular sperm and ICSI. Although genetic fatherhood is now possible for many men previously considered sterile, it is crucial to discover and abrogate causes as best possible, provide reliable and evidenced-based therapy, consider seriously the health and wellness of any offspring conceived, and always view infertility as a possible symptom of a more general or constitutional disease.

Association between total globozoospermia and sperm chromatin defects

Globozoospermia is a severe sperm morphological anomaly leading to primary infertility and low fertilisation following intracytoplasmic sperm injection (ICSI). This phenotype is observed in less than 0.1% of infertile men and is determined by small, round-headed spermatozoa with absence of an acrosomal cap, acrosome protease and also cytoskeletal proteins. Failure of oocyte activation is considered as the main cause of fertilisation failure in these individuals post-ICSI. Therefore, artificial oocyte activation (AOA) along with ICSI is commonly implemented. However, based on previous report, fertilisation rate remains low despite implementation of ICSI-AOA. Therefore, other mechanisms like sperm chromatin packaging and DNA fragmentation may account for low fertilisation and development post-ICSI-AOA. Therefore, this study aims to assess and compare the degree of sperm protamine deficiency and DNA fragmentation in large population of infertile men with total globozoospermia (30 globozoospermic men presenting with 100% round-headed spermatozoa) with 22 fertile individuals using chromomycin A3 and TUNEL assay respectively. Results clearly show that mean of sperm concentration and percentage of sperm motility were significantly lower, while percentage of sperm abnormal morphology, protamine-deficient and DNA-fragmented spermatozoa were significantly higher in infertile men with globozoospermia compared to fertile men. Therefore, increased sperm DNA damage in globozoospermia is likely related to defective DNA compaction and antioxidant therapy before ICSI-AOA could be recommended as an appropriate option before ICSI-AOA.

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

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

Relationship between phospholipase C-zeta, semen parameters, and chromatin status

The need for additional tests to complement basic sperm analysis in clinics is well appreciated. In this regard, a number of tests such as sperm DNA integrity test as a tool in diagnosis and treatment of infertility are suggested. But recent studies have focused on main sperm factors involved in oocyte activation such as phospholipase C-zeta (PLCζ) that initiate intracellular Ca²⁺ signaling and embryogenesis. Therefore, this study aimed to investigate the relationship between PLCζ, basic semen parameters, sperm DNA fragmentation (SDF), and protamine deficiency in men with normal (n=32) and abnormal (n=23) semen parameters. Unlike SDF and protamine deficiency, as negative factors related to fertility, the mean value of PLCζ as positive factor related to infertility was significantly lower in men with abnormal semen parameters compared to men with normal semen parameters. Significant correlations were also observed between sperm concentration, motility, and abnormal morphology with the percentage of PLCζ positive spermatozoa. In addition, logistic regression analysis revealed that sperm morphology is more predictive than sperm motility and concentration for PLCζ presence. In addition, a statistically significant negative relationship was observed between the percentage of PLCζ positive spermatozoa and SDF. These findings suggested during ICSI, selection of sperm based on morphology has a profound effect on its ability to induce oocyte activation based on the likelihood of PLCζ expression. Therefore, assessment of PLCζ as an index for fertilization potential of a semen sample in men with severe teratozoospermia may define individuals who are candidates for artificial oocyte activation (AOA) and may avoid failed fertilization post ICSI.

Sperm with fibrous sheath dysplasia and anomalies in head-neck junction: focus on centriole and centrin 1

Spermatozoa with a rare combination of two monomorphic sperm defects, dysplasia of the fibrous sheath (DFS) and alterations in head-mid-piece junction were analysed. The main focus was to explore the status of the centriole, a key organisation during fertilisation, using the centrin 1, a calcium-binding protein linked to this structure. The sperm quality was examined by light, scanning and transmission electron microscopy (SEM, TEM); immunocytochemistry was performed for tubulin, A-kinase anchor protein 4 (AKAP4) and centrin 1. Spermatozoa showed DFS defect associated with anomalies in head-tail attachment detected by SEM and TEM. Immunolocalisation of tubulin, AKAP4 and centrin 1 confirmed these alterations. Centrin 1 was visible in 67% of spermatozoa (in only 13% centrin localised in a normal position); in the majority of sperm centrin 1's location was altered, sometimes bent; often four spots, indicating the presence of two implantation fossae, were detected. At the centriolar level, immunoreactive fragments, frequently invading the entire short and thick tail, were observed. Centrin 1 is an essential component of the spermatozoa connecting piece and plays a role in centrosome dynamics during sperm morphogenesis and in zygotes and early embryos during spindle assembly. It is important to shed light on these rare conditions in order to better manage the patients during assisted reproductive technology.

Phospholipase C zeta (PLCζ) and male infertility: Clinical update and topical developments

The development of a mammalian embryo is initiated by a sequence of molecular events collectively referred to as 'oocyte activation' and regulated by the release of intracellular calcium in the ooplasm. Over the last decade, phospholipase C zeta (PLCζ), a sperm protein introduced into the oocyte upon gamete fusion, has gained almost universal acceptance as the protein factor responsible for initiating oocyte activation. A large body of consistent and reproducible evidence, from both biochemical and clinical settings, confers support for the role of PLCζ in this fundamental biological context, which has significant ramifications for the management of human male infertility. Oocyte activation deficiency (OAD) and total fertilisation failure (TFF) are known causes of infertility and have both been linked to abnormalities in the structure, expression, and localisation pattern of PLCζ in human sperm. Assisted oocyte activators (AOAs) represent the only therapeutic option available for OAD at present, although these agents have been the source of much debate recently, particularly with regard to their potential epigenetic effects upon the embryo. Consequently, there is much interest in the deployment of sensitive PLCζ assays as prognostic/diagnostic tests and human recombinant PLCζ protein as an alternative form of therapy. Although PLCζ deficiency has been directly linked to a cohort of infertile cases, we have yet to identify the specific causal mechanisms involved. While two genetic mutations have been identified which link defective PLCζ protein to an infertile phenotype, both were observed in the same patient, and have yet to be described in other patients. Consequently, some researchers are investigating the possibility that genetic variations in the form of single nucleotide polymorphisms (SNPs) could provide some explanation, especially since >6000 SNPs have been identified in the PLCζ gene. As yet, however, there is no consistent data to suggest that any of these SNPs influence the functional ability of PLCζ. Other laboratories appear to be focussing upon the PLCζ promoter, which is bi-directional and shared with the actin filament capping muscle Z-line alpha 3 gene (CAPZA3), or seeking to identify interacting proteins within the ooplasm. The aim of this review is to provide a synopsis of recent progress in the application of PLCζ in diagnostic and therapeutic medicine, to discuss our current understanding of how the functional ability of PLCζ might be controlled, and thus how PLCζ deficiency might arise, and finally, to consider the potential implications of alternative sperm protein candidates, such as post-acrosomal WW-domain binding protein (PAWP), which has caused much debate and confusion in the field over the last few years.