Outcome of ICSI with ejaculated spermatozoa in a series of men with distinct ultrastructural flagellar abnormalities

Decreased embryo developmental potential and lower cumulative pregnancy rate in men with multiple morphological abnormalities of the sperm flagella

Objective

Multiple morphological abnormalities of the sperm flagella (MMAF) is characterized by abnormal flagellar phenotypes, which is a particular kind of asthenoteratozoospermia. Previous studies have reported a comparable intracytoplasmic sperm injection (ICSI) outcome in terms of fertilization rate and clinical pregnancy rate in patients with MMAF compared with those with no MMAF; however, others have conflicting opinions. Assisted reproductive technology (ART) outcomes in individuals with MMAF are still controversial and open to debate.

Methods

A total of 38 patients with MMAF treated at an academic reproductive center between January 2014 and July 2022 were evaluated in the current retrospective cohort study and followed up until January 2023. Propensity score matching was used to adjust for the baseline clinical characteristics of the patients and to create a comparable control group. The genetic pathogenesis of MMAF was confirmed by whole exome sequencing. The main outcomes were the embryo developmental potential, the cumulative pregnancy rate (CLPR), and the cumulative live birth rate (CLBR).

Results

Pathogenic variants in known genes of DNAH1, DNAH11, CFAP43, FSIP2, and SPEF2 were identified in patients with MMAF. Laboratory outcomes, including the fertilization rate, 2PN cleavage rate, blastocyst formation rate, and available blastocyst rate, followed a trend of decline in the MMAF group (p < 0.05). Moreover, according to the embryo transfer times and complete cycles, the CLPR in the cohort of MMAF was lower compared with the oligoasthenospermia pool (p = 0.033 and p = 0.020, respectively), while no statistical differences were observed in the neonatal outcomes.

Conclusion

The current study presented decreased embryo developmental potential and compromised clinical outcomes in the MMAF cohort. These findings may provide clinicians with evidence to support genetic counseling and clinical guidance in specific patients with MMAF.

Nuclear sperm integrity and ICSI prognosis in Tunisian patients with MMAF syndrome (multiple morphological abnormalities of the sperm flagella)

Multiple Morphological Abnormalities of the Sperm Flagella (MMAF) is a severe form of teratozoospermia associated with several sperm flagellar abnormalities. The study included 52 patients with MMAF syndrome and a control group of 25 fertile men. The impact of nuclear sperm quality on intracytoplasmic sperm injection (ICSI) results was studied in 20 couples. TUNEL assay was used to assess sperm DNA fragmentation and aniline-blue staining was used to assess chromatin condensation. To investigate chromosomal meiotic segregation, we used fluorescence in situ hybridization (FISH). Semen morphology analysis revealed a mosaic of multiple flagella morphological abnormalities, including 46.73% short flagella, 16.22% bent flagella, 22.07% coiled flagella, and 10.90% absent flagella, all of which were associated with a high percentage of sperm head abnormalities. The mean DNA fragmentation index was substantially higher in patients compared to controls (p = 0.001), whereas the rate of aniline blue-reacted spermatozoa was not significantly different. There was a significant difference in aneuploidy frequencies between the two groups (p < 0.05). Infertile males with MMAF syndrome had lower sperm nuclear quality, which affected ICSI results. As a result, better sperm selection procedures are being employed to increase the success rate of assisted reproductive technologies (ART).

Surgically retrieved spermatozoa for ICSI cycles in non-azoospermic males with high sperm DNA fragmentation in semen

Intracytoplasmic sperm injection (ICSI) using surgically retrieved spermatozoa outside the classic context of azoospermia has been increasingly used to overcome infertility. The primary indications include high levels of sperm DNA damage in ejaculated spermatozoa and severe oligozoospermia or cryptozoospermia, particularly in couples with ICSI failure for no apparent reason. Current evidence suggests that surgically retrieved spermatozoa for ICSI in the above context improves  outcomes, mainly concerning pregnancy and miscarriage rates. The reasons are not fully understood but may be related to the lower levels of DNA damage in spermatozoa retrieved from the testis compared with ejaculated counterparts. These findings are consistent with the notion that excessive sperm DNA damage  can be a limiting factor responsible for the failure to conceive. Using testicular in preference of low-quality ejaculated spermatozoa bypasses post-testicular sperm DNA damage caused primarily by oxidative stress, thus increasing the likelihood of oocyte fertilization by genomically intact spermatozoa. Despite the overall favorable results, data remain limited, and mainly concern males with confirmed sperm DNA damage in the ejaculate. Additionally, information regarding the health of ICSI offspring resulting from the use of surgically retrieved spermatoa of non-azoospermic males is still lacking. Efforts should be made to improve the male partner's reproductive health for safer ICSI utilization. A comprehensive andrological evaluation aiming to identify and treat the underlying male infertility factor contributing to sperm DNA damage is essential for achieving this goal.

Results and perinatal outcomes from 189 ICSI cycles of couples with asthenozoospermic men and flagellar defects assessed by transmission electron microscopy

RESEARCH QUESTION

Do patients presenting with flagella ultrastructural defects as assessed by electron microscopy, and defined within three phenotypes (dysplasia of the fibrous sheath [DFS], primary flagellar dyskinesia [PFD] and non-specific flagellar abnormalities [NSFA]), have decreased chances of success in intracytoplasmic sperm injection (ICSI) or adverse obstetric and neonatal outcomes?

DESIGN

Retrospective analysis of 189 ICSI cycles from 80 men with spermatozoa flagellum ultrastructural defects (DFS [n = 16]; PFD [n = 14]; NSFA [n = 50] compared with a control group (n = 97). Cycles were cumulatively analysed. All fresh and frozen embryo transfers resulting from each ICSI attempt were included. The effect of transmission electron microscopy (TEM) phenotype on the main ICSI outcomes was assessed by a multivariate logistic regression combined with a generalized linear mixed model to account for the non-independence of the observations.

RESULTS

No predictive value of TEM phenotype was found on the main outcomes of ICSI, namely fertilization rates, pregnancy and delivery rates, and cumulative pregnancy and delivery rates. Cumulative pregnancy rates ranged from 29.0-43.3% in the different TEM phenotype subgroups compared with 36.8% in the control group. Cumulative live birth rates ranged from 24.6-36.7% compared with 31.4% in the control group. No increase was found in miscarriages, preterm births, low birth weights or birth abnormalities.

CONCLUSIONS

Data on the cumulative chances of success in ICSI of patients with ultrastructural flagellar defects, a rare cause of male infertility often associated with an underlying genetic cause, are reassuring, as are obstetrical and neonatal outcomes in this population.

Novel DNAH1 Mutation Loci Lead to Multiple Morphological Abnormalities of the Sperm Flagella and Literature Review

The protein encoded by dynein axonemal heavy chain 1 (DNAH1) is a part of dynein, which regulates the function of cilia and sperm flagella. The mutant of DNAH1 causes the deletion of inner dynein arm 3 in the flagellum, leading to multiple morphological abnormalities of the sperm flagella (MMAF) and severe asthenozoospermia. However, instead of asthenozoospermia and MMAF, the result caused by the mutation of DNAH1 remains unknown. Here we report a male infertility patient with severe asthenozoospermia and teratozoospermia. We found two heterozygous mutations in DNAH1 (c.6912C>A and c.7076G>T) and which were reported to be associated with MMAF for the first time. We next collected and analyzed 65 cases of DNAH1 mutation and found that the proportion of short flagella is the largest, while the bent flagella account for the smallest, and the incidence of head deformity is not high in the sperm of these patients. Finally, we also analyzed 31 DNAH1 mutation patients who were treated with intracytoplasmic sperm injection (ICSI) and achieved beneficial outcomes. We hope our research will be helpful in the diagnosis and treatment of male infertility caused by DNAH1 mutation.

Genetic diagnosis, sperm phenotype and ICSI outcome in case of severe asthenozoospermia with multiple morphological abnormalities of the flagellum

STUDY QUESTION

Are ICSI outcomes impaired in cases of severe asthenozoospermia with multiple morphological abnormalities of the flagellum (MMAF phenotype)?

SUMMARY ANSWER

Despite occasional technical difficulties, ICSI outcomes for couples with MMAF do not differ from those of other couples requiring ICSI, irrespective of the genetic defect.

WHAT IS KNOWN ALREADY

Severe asthenozoospermia, especially when associated with the MMAF phenotype, results in male infertility. Recent findings have confirmed that a genetic aetiology is frequently responsible for this phenotype. In such situations, pregnancies can be achieved using ICSI. However, few studies to date have provided detailed analyses regarding the flagellar ultrastructural defects underlying this phenotype, its genetic aetiologies, and the results of ICSI in such cases of male infertility.

STUDY DESIGN, SIZE, DURATION

We performed a retrospective study of 25 infertile men exhibiting severe asthenozoospermia associated with the MMAF phenotype identified through standard semen analysis. They were recruited at an academic centre for assisted reproduction in Paris (France) between 2009 and 2017. Transmission electron microscopy (TEM) and whole exome sequencing (WES) were performed in order to determine the sperm ultrastructural phenotype and the causal mutations, respectively. Finally 20 couples with MMAF were treated by assisted reproductive technologies based on ICSI.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients with MMAF were recruited based on reduced sperm progressive motility and increased frequencies of absent, short, coiled or irregular flagella compared with those in sperm from fertile control men. A quantitative analysis of the several ultrastructural defects was performed for the MMAF patients and for fertile men. The ICSI results obtained for 20 couples with MMAF were compared to those of 378 men with oligoasthenoteratozoospermia but no MMAF as an ICSI control group.

MAIN RESULTS AND THE ROLE OF CHANCE

TEM analysis and categorisation of the flagellar anomalies found in these patients provided important information regarding the structural defects underlying asthenozoospermia and sperm tail abnormalities. In particular, the absence of the central pair of axonemal microtubules was the predominant anomaly observed more frequently than in control sperm (P < 0.01). Exome sequencing, performed for 24 of the 25 patients, identified homozygous or compound heterozygous pathogenic mutations in CFAP43, CFAP44, CFAP69, DNAH1, DNAH8, AK7, TTC29 and MAATS1 in 13 patients (54.2%) (11 affecting MMAF genes and 2 affecting primary ciliary dyskinesia (PCD)-associated genes). A total of 40 ICSI cycles were undertaken for 20 MMAF couples, including 13 cycles (for 5 couples) where a hypo-osmotic swelling (HOS) test was required due to absolute asthenozoospermia. The fertilisation rate was not statistically different between the MMAF (65.7%) and the non-MMAF (66.0%) couples and it did not differ according to the genotype or the flagellar phenotype of the subjects or use of the HOS test. The clinical pregnancy rate per embryo transfer did not differ significantly between the MMAF (23.3%) and the non-MMAF (37.1%) groups. To date, 7 of the 20 MMAF couples have achieved a live birth from the ICSI attempts, with 11 babies born without any birth defects.

LIMITATIONS, REASONS FOR CAUTION

The ICSI procedure outcomes were assessed retrospectively on a small number of affected subjects and should be confirmed on a larger cohort. Moreover, TEM analysis could not be performed for all patients due to low sperm concentrations, and WES results are not yet available for all of the included men.

WIDER IMPLICATIONS OF THE FINDINGS

An early and extensive phenotypic and genetic investigation should be considered for all men requiring ICSI for severe asthenozoospermia. Although our study did not reveal any adverse ICSI outcomes associated with MMAF, we cannot rule out that some rare genetic causes could result in low fertilisation or pregnancy rates.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was used for this study and there are no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Successful birth after ICSI with testicular immotile spermatozoa from a patient with total MMAF in the ejaculates: a case report

There has been no report on the outcome of vitrified blastocyst transfer from a vitrified oocyte injected with immotile testicular spermatozoa with only multiple morphological abnormalities of the sperm flagella (MMAF). A couple diagnosed with MMAF returned to the clinic to attempt pregnancy using their vitrified oocytes. Testicular spermatozoa were injected intracytoplasmically, and the following intracytoplasmic sperm injection results were observed. In the second cycle, surplus vitrified oocytes and testicular retrieved sperm were used, but no pregnancy ensued. In the third cycle, a surplus vitrified blastocyst was transferred, and a healthy female child was delivered, with a birth weight of 3050 g and a birth length of 53 cm. In this report we describe a successful pregnancy achieved in a patient presenting MMAF. The successful pregnancy was obtained from vitrified oocytes microinjected with testicular retrieved sperm in a vitrified blastocyst transfer.

Diagnostics and Management of Male Infertility in Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD), a disease caused by the malfunction of motile cilia, manifests mainly with chronic recurrent respiratory infections. In men, PCD is also often associated with infertility due to immotile sperm. Since causative mutations for PCD were identified in over 50 genes, the role of these genes in sperm development should be investigated in order to understand the effect of PCD mutations on male fertility. Previous studies showed that different dynein arm heavy chains are present in respiratory cilia and sperm flagellum, which may partially explain the variable effects of mutations on airways and fertility. Furthermore, recent studies showed that male reproductive tract motile cilia may play an important part in sperm maturation and transport. In some PCD patients, extremely low sperm counts were reported, which may be due to motile cilia dysfunction in the reproductive tract rather than problems with sperm development. However, the exact roles of PCD genes in male fertility require additional studies, as do the treatment options. In this review, we discuss the diagnostic and treatment options for men with PCD based on the current knowledge.

Insight on multiple morphological abnormalities of sperm flagella in male infertility: what is new?

The syndrome of multiple morphological abnormalities of the sperm flagella (MMAF) is a specific kind of asthenoteratozoospermia with a mosaic of flagellar morphological abnormalities (absent, short, bent, coiled, and irregular flagella). MMAF was proposed in 2014 and has attracted increasing attention; however, it has not been clearly understood. In this review, we elucidate the definition of MMAF from a systematical view, the difference between MMAF and other conditions with asthenoteratozoospermia or asthenozoospermia (such as primary mitochondrial sheath defects and primary ciliary dyskinesia), the knowledge regarding its etiological mechanism and related genetic findings, and the clinical significance of MMAF for intracytoplasmic sperm injection and genetic counseling. This review provides the basic knowledge for MMAF and puts forward some suggestions for further investigations.

Observational retrospective study of Intracytoplasmic sperm injection outcomes of 117 infertile men with severe short tail sperm defect

Intracytoplasmic sperm injection (ICSI) is increasingly used to treat male-factor infertility when sperm parameters are not proper for intrauterine insemination (IUI) or in vitro fertilization (IVF). Among sperm abnormalities, short tail sperm defect is a rare kind of teratozoospermia, which is a severe cause of male infertility. In this study, we evaluated the ICSI outcomes of infertile men with severely short tail sperm defect. 117 infertile men with primary infertility were included in this study. We evaluated the impact of short tail sperm defect on large ICSI series (228 cycles) outcomes. The fertilisation rate (FR) was 49.0%, the clinical pregnancy rate (PR) was 21.7%, and the delivery rate (DR) was 17.5%. The results of statistical analysis show that there is no relationship between short tail sperm defect and clinical pregnancy. According to the present study, there were patients with successful ICSI outcomes despite the severe defect in their spermatozoa flagella. Our results can be considered in two main aspects: (a) it seems that ICSI could be a proper therapy for infertile men with short-tailed sperm defect and (b) the abnormal sperm morphology (especially in sperm flagellum) is not a reliable predictor for the ICSI outcomes. In conclusion, our study suggests that ICSI should be considered as a proper treatment way for infertile men with severe short tail sperm defect and probably other sperm flagella abnormalities.

Sperm DNA fragmentation testing: Summary evidence and clinical practice recommendations

We herein summarise the evidence concerning the impact of sperm DNA fragmentation in various clinical infertility scenarios and the advances on sperm DNA fragmentation tests. The collected evidence was used to formulate 41 recommendations. Of these, 13 recommendations concern technical aspects of sperm DNA fragmentation testing, including pre-analytical information, clinical thresholds and interpretation of results. The remaining 28 recommendations relate to indications for sperm DNA fragmentation testing and clinical management. Clinical scenarios like varicocele, unexplained infertility, idiopathic infertility, recurrent pregnancy loss, intrauterine insemination, in vitro fertilisation/intracytoplasmic sperm injection, fertility counselling for men with infertility risk factors and sperm cryopreservation have been contemplated. The bulk evidence supporting the recommendations has increased in recent years, but it is still of moderate to low quality. This guideline provides clinicians with advice on best practices in sperm DNA fragmentation testing. Also, recommendations are provided on possible management strategies to overcome infertility related to sperm DNA fragmentation, based on the best available evidence. Lastly, we identified gaps in knowledge and opportunities for research and elaborated a list of recommendations to stimulate further investigation.

Sperm retrieval and intracytoplasmic sperm injection outcomes with testicular sperm aspiration in men with severe oligozoospermia and cryptozoospermia

INTRODUCTION

Several studies addressed the role of testicular sperm aspiration with intracytoplasmic sperm injection (ICSI) in azoospermic men, but few have included non-azoospermic men. The aim of this study was to evaluate testicular sperm aspiration (TESA) sperm retrieval rates and ICSI outcomes in men with severe oligozoospermia.

METHODS

Data were collected retrospectively from 88 consecutive, non-azoospermic, infertile men with idiopathic severe oligozoospermia who underwent TESA between January 2011 and January 2018. Patients were categorized into four groups according to sperm concentration: <5 and >1 million/ml (group 1), <1 and > 0.1 million/ml (group 2), <0.1 million/ml (group 3), and cryptozoospermia (group 4).

RESULTS

Mean male age was 37±7 years and the mean female age was 33±4 years. Sperm was recovered successfully in 90% (79/88) of the men overall and in 100% (30/30) of the men in group 1, 97% (29/30) of the men in group 2, 88% (15/17) of the men in group 3, and 45% (5/11) of the men in group 4. Most (65%, 57/88) of the couples had an embryo transfer (ET). The overall clinical pregnancy rate per ET was 46% (26/57). The clinical pregnancy rates (per ET) were 43% (9/21) in group 1, 65% (13/20) in group 2, 36% (4/11) in group 3, and 0% (0/5) in group 4.

CONCLUSIONS

Our data indicate TESA allows for high sperm retrieval rates and acceptable ICSI pregnancy rates in men with severe oligozoospermia. However, in our experience, TESA sperm retrieval rates and ICSI outcomes are poor in cryptozoospermic men.

Is there a role for phosphodiesterase inhibitors in the treatment of male subfertility?

Intracytoplasmic sperm injection (ICSI) is frequently used to overcome severe deficits in semen quality. Concerns, however, are arising over its increasing use for non-male factor infertility. Moreover, increased risk of cardiovascular disease, congenital abnormalities, aneuploidies and childhood cancers have all been reported in the literature in relation to ICSI and it is possible that the quality of sperm chosen for injection may be an important factor in these unwanted outcomes. Given the wider adoption of ICSI to treat beyond the requirements of male infertility alone, research focussed on alternative methods to diagnose and treat the infertile couple is gaining increasing attention. This review focuses on the information available to date on the use of non-selective phosphodiesterase inhibitors (PDEI), specifically pentoxifylline (PF), caffeine (CF) and theophylline (TP) to stimulate sperm motility, thereby potentially reducing the need for ICSI in certain patient groups who may benefit from either expectant management or from a less stressful, minimally invasive and inexpensive treatment such as intrauterine insemination (IUI). The review focuses firstly on the mechanism of action of PDEI followed by treatment effects on sperm parameters such as motility and hyperactivated motility and sperm DNA integrity. Specific clinical implications are discussed that outline the potential role of PDEI in clinical practice and highlights areas in need of further research.

Successful pregnancy and delivery achieved following intracytoplasmic sperm injection using teratozoospermic sperm exhibiting marked dysplasia of the fibrous sheath: a case report

A husband and his wife, both 34 years old, consulted our clinic because of primary infertility. Sperm analysis revealed that the sperm concentration, motility, and progressive motility were (42.8±22.8)×10⁶/mL, 23.3%±12.2%, and 12.9%±6.1%, respectively. Based on Krugar strict morphology criteria, 100% of the sperm were teratozoospermic, with 7.9% DNA fragmentation index. Observation of the sperm under a transmission electron microscope revealed that most parts of the fibrous sheath (FS) surrounding the tails of the sperm were missing from midway through the principal piece to the end piece, although the sperm’s heads, necks and midpieces were morphologically normal. To collect oocytes, the gonadotropin-releasing hormone antagonist protocol was carried out, and 7 oocytes were retrieved. Intracytoplasmic sperm injection (ICSI) was performed for all the teratozoospermic sperm. Of the 7 oocytes, 3 were fertilized, and one 8-cell embryo and 2 expanded blastocysts were vitrified. Although repeated transfers of expanded blastocysts resulted in no implantation, one 8-cell embryo transfer in a hormone replacement therapy cycle led to pregnancy. The pregnancy using an 8-cell vitrified embryo resulted in the delivery of a healthy female baby at 38 weeks of gestation. No congenital malformations were found until 28 days after birth. Our results demonstrated that healthy birth could be achieved following the transfer of an embryo derived from ICSI using teratozoospermic sperm exhibiting the dysplasia of the fibrous sheath (DFS). Furthermore, while the previous reports on DFS have not investigated male infertility, we evaluated sperms from various aspects such as Kruger sperm function test, chromatin dispersion test, electron microscopy findings, time-lapse images of the obtained embryos, and concluded that ICSI could be desirable as a treatment policy for DFS.

Extended indications for sperm retrieval: summary of current literature

Sperm retrieval combined with intracytoplasmic sperm injection (ICSI) is the treatment of choice for couples with untreatable azoospermia-related infertility. However, an increasing body of evidence has been mounting, suggesting that ICSI with testicular sperm instead of ejaculated sperm (when both are available) increases pregnancy outcomes in some specific scenarios. This has led to the exploration of extended indications for sperm retrieval. This review summarizes the current literature concerning sperm retrieval and ICSI for non-azoospermic men with elevated sperm DNA fragmentation, oligozoospermia, and cryptozoospermia.

Intracytoplasmic sperm injection for male infertility and consequences for offspring

Intracytoplasmic sperm injection (ICSI) has become the most commonly used method of fertilization in assisted reproductive technology. The primary reasons for its popularity stem from its effectiveness, the standardization of the procedure, which means that it can easily be incorporated into the routine practice of fertility centres worldwide, and the fact that it can be used to treat virtually all forms of infertility. ICSI is the clear method of choice for overcoming untreatable severe male factor infertility, but its (over)use in other male and non-male factor infertility scenarios is not evidence-based. Despite all efforts to increase ICSI efficacy and safety through the application of advanced sperm retrieval and cryopreservation techniques, as well as methods for selecting sperm with better chromatin integrity, the overall pregnancy rates from infertile men remain suboptimal. Treating the underlying male infertility factor before ICSI seems to be a promising way to improve ICSI outcomes, but data remain limited. Information regarding the health of ICSI offspring has accumulated over the past 25 years, and there are reasons for concern as risks of congenital malformations, epigenetic disorders, chromosomal abnormalities, subfertility, cancer, delayed psychological and neurological development, and impaired cardiometabolic profile have been observed to be greater in infants born as a result of ICSI than in naturally conceived children. However, as subfertility probably influences the risk estimates, it remains to be determined to what extent the observed adverse outcomes are related to parental factors or associated with ICSI.

Whole-exome sequencing identifies mutations in FSIP2 as a recurrent cause of multiple morphological abnormalities of the sperm flagella

STUDY QUESTION

Can whole-exome sequencing (WES) of infertile patients identify new genes responsible for multiple morphological abnormalities of the sperm flagella (MMAF)?

SUMMARY ANSWER

WES analysis of 78 infertile men with a MMAF phenotype permitted the identification of four homozygous mutations in the fibrous sheath (FS) interacting protein 2 (FSIP2) gene in four unrelated individuals.

WHAT IS KNOWN ALREADY

The use of high-throughput sequencing techniques revealed that mutations in the dynein axonemal heavy chain 1 (DNAH1) gene, and in the cilia and flagella associated protein 43 (CFAP43) and 44 (CFAP44) genes account for approximately one-third of MMAF cases thus indicating that other relevant genes await identification.

STUDY DESIGN, SIZE, DURATION

This was a retrospective genetics study of 78 patients presenting a MMAF phenotype who were recruited in three fertility clinics between 2008 and 2015. Control sperm samples were obtained from normospermic donors. Allelic frequency for control subjects was derived from large public databases.

PARTICIPANTS/MATERIALS, SETTING, METHODS

WES was performed for all 78 subjects. All identified variants were confirmed by Sanger sequencing. Relative mRNA expression levels for the selected candidate gene (FSIP2) was assessed by quantitative RT-PCR in a panel of normal human and mouse tissues. To characterize the structural and ultrastructural anomalies present in patients' sperm, immunofluorescence (IF) was performed on sperm samples from two subjects with a mutation and one control and transmission electron microscopy (TEM) analyses was performed on sperm samples from one subject with a mutation and one control.

MAIN RESULTS AND THE ROLE OF CHANCE

We identified four unrelated patients (4/78, 5.1%) with homozygous loss of function mutations in the FSIP2 gene, which encodes a protein of the sperm FS and is specifically expressed in human and mouse testis. None of these mutations were reported in control sequence databases. TEM analyses showed a complete disorganization of the FS associated with axonemal defects. IF analyses confirmed that the central-pair microtubules and the inner and outer dynein arms of the axoneme were abnormal in all four patients carrying FSIP2 mutations. Importantly, and in contrast to what was observed in patients with MMAF and mutations in other MMAF-related genes (DNAH1, CFAP43 and CFAP44), mutations in FSIP2 led to the absence of A-kinase anchoring protein 4 (AKAP4).

LIMITATIONS, REASONS FOR CAUTION

The low number of biological samples and the absence of a reliable anti-FSIP2 antibody prevented the formal demonstration that the FSIP2 protein was absent in sperm from subjects with a FSIP2 mutation.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings indicate that FSIP2 is one of the main genes involved in MMAF syndrome. In humans, genes previously associated with a MMAF phenotype encoded axonemal-associated proteins (DNAH1, CFAP43 and CFAP44). We show here that FSIP2, a protein of the sperm FS, is also logically associated with MMAF syndrome as we showed that it is necessary for FS assembly and for the overall axonemal and flagellar biogenesis. As was suggested before in mouse and man, our results also suggest that defects in AKAP4, one of the main proteins interacting with FSIP2, would induce a MMAF phenotype. Finally, this work reinforces the demonstration that WES sequencing is a good strategy to reach a genetic diagnosis for patients with severe male infertility phenotypes.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the following grants: the 'MAS-Flagella' project financed by the French ANR and the DGOS for the program PRTS 2014 (14-CE15) and the 'Whole genome sequencing of patients with Flagellar Growth Defects (FGD)' project financed by the Fondation Maladies Rares for the program Séquençage à haut débit 2012. The authors have no conflict of interest.

Characterisation of three systematic sperm tail defects and their influence on ICSI outcome

This study characterized three cases of systematic sperm tail defects using electron microscopy and immunolocalisation of centrin 1 and tubulin and explored their impact on ICSI outcome. Structural sperm tail defects of possible genetic origin were suspected as the eosin test revealed a sperm viability of >70% despite severe asthenozoospermia or the absence of motility. In Patient 1, 80%-85% of axoneme cross sections was incomplete. The fluorescent signal of tubulin was weak along the entire tail; the signal of centrin 1 was normal. After ICSI, a female healthy baby was born. Patient 2 showed spermatozoa with tails reduced in length at different levels, axonemal and periaxonemal alterations and fragility of head-tail junction. Centrin 1 was altered in 80% of sperm. After ICSI, no embryos were obtained. Patient 3 showed tails reduced in length at light and fluorescence microscopy; ultrastructural study revealed a condition of dysplasia of fibrous sheath with heterogeneity of tails' length. The signal for centrin 1 was altered in 50% of spermatozoa; two embryos were transferred without pregnancy. The correct diagnosis of sperm pathology is important in case of systematic sperm defects as it enables the clinician to improve patient's management and to provide an adequate genetic counselling.

Reproductive outcomes of testicular versus ejaculated sperm for intracytoplasmic sperm injection among men with high levels of DNA fragmentation in semen: systematic review and meta-analysis

OBJECTIVE

To compare sperm DNA fragmentation (SDF) levels between testicular and ejaculated sperm and to evaluate outcomes of intracytoplasmic sperm injection (ICSI) with the use of testicular (Testi-ICSI) versus ejaculated (Ejac-ICSI) sperm in nonazoospermic men with high SDF.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Normo- and oligozoospermic men with high levels of SDF in semen subjected to Testi-ICSI or Ejac-ICSI.

INTERVENTION(S)

Summary mean difference (MD) and odds ratio (OR) were calculated with the use of an inverse variance model and fixed- or random-effects models, respectively.

MAIN OUTCOME MEASURE(S)

Primary outcomes were SDF levels, clinical pregnancy rates (CPRs), and live birth rates (LBRs). Secondary outcomes were fertilization and miscarriage rates.

RESULT(S)

Five studies involving 143 patients provided paired SDF rates for testicular and ejaculated sperm, revealing lower SDF in testicular sperm (MD -24.58%). Four studies involving 507 cycles and 3,840 oocytes reported clinical outcomes of Testi-ICSI and Ejac-ICSI. Fertilization rates were not different between sperm sources, but a trend to lower rates was observed with Testi-ICSI. CPRs were higher for Testi-ICSI than for Ejac-ICSI, as were LBRs, whereas miscarriage rates were reduced with Testi-ICSI.

CONCLUSION(S)

Testicular sperm have lower levels of SDF than ejaculated sperm, with Testi-ICSI for high post-testicular SDF men improving reproductive outcomes compared with Ejac-ICSI. Infertile couples may benefit from Testi-ICSI if male partners have confirmed high SDF in the ejaculate.

Sperm DNA damage and its role in IVF and ICSI

While the semen analysis has traditionally been relied upon to differentiate fertile and infertile men, its utility has been questioned in the current era of assisted reproductive technologies. The desire for more sophisticated diagnostic and predictive tools has led to increased use of sperm DNA damage in the management of male infertility. Despite the availability of numerous assays to measure sperm DNA damage, our understanding of the etiology, measurement, and clinical implications of sperm DNA damage remains incomplete. While the current evidence is fraught with heterogeneity that complicates attempts at comparison and meta-analysis, there does appear to be a role for sperm DNA damage in the development and maintenance of pregnancy in the era of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). However, as noted by the American Society for Reproductive Medicine, the routine and widespread use of sperm DNA damage testing is not yet supported. Further studies are needed to standardize the measurement of sperm DNA damage and to clarify the exact role of sperm DNA damage within the myriad of other male and female factors contributing to reproductive outcomes in IVF and ICSI.

Use of testicular sperm for ICSI in oligozoospermic couples: how far should we go?

In 1992 and subsequently, several reports indicated that ICSI was a successful technique to achieve clinical pregnancy and live birth using spermatozoa with severely impaired characteristics. The initial optimism over the ability of ICSI to overcome significant sperm abnormalities was later tempered by the findings of more recent publications suggesting that some sperm deficits may not be as effectively treated with ICSI. In search for effective treatment for couples with severe male factor, a number of small retrospective and prospective studies have reported high pregnancy and live birth rates using testicular sperm for men with necrozoospermia, cryptozoospermia and oligozoospermia with or without elevated sperm DNA damage. Although the data suggest that there may be some benefit in performing testicular sperm retrieval (TSR)-ICSI in select groups of non-azoospermic infertile men, there are potential risks involved with TSR. Clinicians should balance these risks prior to the recommendation of TSR-ICSI on the result of a semen analysis or sperm DNA test alone. Careful evaluation and management of male factor infertility is important. The use of TSR-ICSI in the absence of specific sperm DNA defects is still experimental.

Patients with multiple morphological abnormalities of the sperm flagella due to DNAH1 mutations have a good prognosis following intracytoplasmic sperm injection

STUDY QUESTION

Does DNAH1 status influence intracytoplasmic sperm injection (ICSI) outcomes for patients with multiple morphological abnormalities of the sperm flagella (MMAF)?

SUMMARY ANSWER

Despite a highly abnormal morphology, sperm from MMAF patients with DNAH1 mutations have a low aneuploidy rate and good nuclear quality, leading to good embryonic development following ICSI and a high pregnancy rate.

WHAT IS KNOWN ALREADY

Teratozoospermia represents a heterogeneous group including a wide range of phenotypes. Among all these qualitative defects, a flagellar phenotype called MMAF is characterized by a mosaic of morphological abnormalities of the flagellum, including coiled, bent, irregular, short or/and absent flagella, mainly due to the absence of the axonemal central pair microtubules. We previously demonstrated that homozygous mutations in the DNAH1 gene, encoding an inner arm heavy chain dynein, are frequently found in patients with MMAF (28% of the patients from the initial cohort). Numerous studies have reported an increased rate of aneuploidy and a poor sperm nuclear quality related to sperm flagellar abnormalities, which could impede ICSI outcome. Moreover, success rates after ICSI may be influenced by the type of ultrastructural flagellar defects and/or by the gene defects carried by the patients.

STUDY DESIGN, SIZE, DURATION

This retrospective cohort study included 6 infertile males with MMAF due to deleterious homozygous DNAH1 mutations and their respective spouses, who underwent 9 ISCI cycles, with 16 embryos being transferred. ICSI results were compared with two control populations of 13 MMAF men without DNAH1 mutations and an aged-matched control group of 1431 non-MMAF couples. All ICSI attempts took place between 2000 and 2012.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Clinical and biological data were collected from patients treated for infertility at the CPSR les Jasmins in Tunis (Tunisia). We compared the ICSI outcomes obtained with couples including DNAH1 mutated and nonmutated patients and non-MMAF couples. For the analysis of the chromosomal status, fluorescence in situ hybridization (FISH) analyses were performed on sperm cells from 3 DNAH1-mutated patients and from 29 fertile control subjects. Sperm chromatin condensation and DNA fragmentation were evaluated using aniline blue staining and TUNEL assays, respectively, on sperm cells from 3 DNAH1-mutated men and 6 fertile controls.

MAIN RESULTS AND THE ROLE OF CHANCE

There was a significantly increased proportion of disomy XY and 18 in sperm from DNAH1 mutated patients compared with fertile controls (1.52 versus 0.28%, P = 0.0001 and 0.64 versus 0.09%, P = 0.0001). However, there were no statistically significant differences among sperm from the two groups in their frequencies of either 13, 21, XX or YY disomy or diploidy. Measures of DNA compaction and fragmentation demonstrated a good nuclear sperm quality among DNAH1 mutated men. The overall fertilization, pregnancy and delivery rates of couples including DNAH1 mutated men were of 70.8, 50.0 and 37.5%, respectively. There were no statistically significant differences in any of these parameters compared with the two control groups (P > 0.05).

LIMITATIONS, REASONS FOR CAUTION

A limitation of this study is the small number of DNAH1-mutated patients available and the low number of genes identified in MMAF. Further genetic studies are warranted to identify other MMAF-inducing genes to better characterize the genetic etiology of the MMAF phenotype and to improve the management of patients diagnosed with flagellar defects.

WIDER IMPLICATIONS OF THE FINDINGS

MMAF patients with DNAH1 mutations have low aneuploidy rates and good nuclear sperm quality, explaining the high pregnancy rate obtained with these patients. Good ICSI results were obtained for both MMAF groups (DNAH1 mutated and nonmutated), suggesting that patients presenting with asthenozoospermia due to flagellar defects have a good ICSI prognosis irrespective of their genotype. The majority of MMAF cases currently remain idiopathic with no genetic cause yet identified. In depth genetic analysis of these patients using next generation sequencing should reveal new causal genes. Subsequent genotype phenotype analyses could improve advice and care provided to MMAF patients.

STUDY FUNDING/COMPETING INTERESTS

None of the authors have any competing interest. This work is part of the project 'Identification and Characterization of Genes Involved in Infertility (ICG2I)', funded by the program GENOPAT 2009 from the French Research Agency (ANR) and the MAS-Flagella project, financed by the French ANR and the Direction Générale de l'Offre de Soins (DGOS).

Teratozoospermia: spotlight on the main genetic actors in the human

BACKGROUND

Male infertility affects >20 million men worldwide and represents a major health concern. Although multifactorial, male infertility has a strong genetic basis which has so far not been extensively studied. Recent studies of consanguineous families and of small cohorts of phenotypically homogeneous patients have however allowed the identification of a number of autosomal recessive causes of teratozoospermia. Homozygous mutations of aurora kinase C (AURKC) were first described to be responsible for most cases of macrozoospermia. Other genes defects have later been identified in spermatogenesis associated 16 (SPATA16) and dpy-19-like 2 (DPY19L2) in patients with globozoospermia and more recently in dynein, axonemal, heavy chain 1 (DNAH1) in a heterogeneous group of patients presenting with flagellar abnormalities previously described as dysplasia of the fibrous sheath or short/stump tail syndromes, which we propose to call multiple morphological abnormalities of the flagella (MMAF).

METHODS

A comprehensive review of the scientific literature available in PubMed/Medline was conducted for studies on human genetics, experimental models and physiopathology related to teratozoospermia in particular globozoospermia, large headed spermatozoa and flagellar abnormalities. The search included all articles with an English abstract available online before September 2014.

RESULTS

Molecular studies of numerous unrelated patients with globozoospermia and large-headed spermatozoa confirmed that mutations in DPY19L2 and AURKC are mainly responsible for their respective pathological phenotype. In globozoospermia, the deletion of the totality of the DPY19L2 gene represents ∼ 81% of the pathological alleles but point mutations affecting the protein function have also been described. In macrozoospermia only two recurrent mutations were identified in AURKC, accounting for almost all the pathological alleles, raising the possibility of a putative positive selection of heterozygous individuals. The recent identification of DNAH1 mutations in a proportion of patients with MMAF is promising but emphasizes that this phenotype is genetically heterogeneous. Moreover, the identification of mutations in a dynein strengthens the emerging point of view that MMAF may be a phenotypic variation of the classical forms of primary ciliary dyskinesia. Based on data from human and animal models, the MMAF phenotype seems to be favored by defects directly or indirectly affecting the central pair of axonemal microtubules of the sperm flagella.

CONCLUSIONS

The studies described here provide valuable information regarding the genetic and molecular defects causing infertility, to improve our understanding of the physiopathology of teratozoospermia while giving a detailed characterization of specific features of spermatogenesis. Furthermore, these findings have a significant influence on the diagnostic strategy for teratozoospermic patients allowing the clinician to provide the patient with informed genetic counseling, to adopt the best course of treatment and to develop personalized medicine directly targeting the defective gene products.

Meiotic segregation and sperm DNA fragmentation in Tunisian men with dysplasia of the fibrous sheath (DFS) associated with head abnormalities

PURPOSE

Dysplasia of the Fibrous Sheath (DFS) is a primitive flagellar pathology for which a broad spectrum of ultrastructural flagellar abnormalities has been described responsible for a severe to total asthenozoospermia. To this phenotype other morphological abnormalities including cephalic and abnormalities in nuclear structure can be associated that could compromise embryonic development in case of use of Assisted Reproductive Technology (ART). The aim of this study was to evaluate the level of DNA fragmentation and aneuploidy rate in ejaculated spermatozoa of Tunisian men presented with DFS sperm defect associated to high percentage of head abnormalities and to compare the results with those from fertile men.

METHODS

Sperm DNA fragmentation was evaluated by the terminal desoxynucleotidyl transferase mediated deoxyuridine triphosphate biotin nick-end labelling (TUNEL) assay. The study of meiotic segregation was performed by Fluorescence in situ hybridization (FISH) for chromosomes X, Y and 18.

RESULTS

The mean DNA fragmentation index was significantly higher in patients compared to the control group. FISH revealed a significantly higher incidence of sperm aneuploidies compared with controls. All patients showed elevated frequencies of sex chromosomes disomy, disomy 18 and diploidy.

CONCLUSIONS

In some cases of syndromic teratozoospermia due to sperm tail structural abnormalities, such as DFS, other morphological cephalic abnormalities may be associated. In these cases we have demonstrated impaired sperm nuclear quality which will affect the results in ICSI. Hence the interest of a thorough study of the sperm nucleus in these forms of infertility in order to predict the chances of success in ART.

Light microscopy morphological characteristics of the sperm flagellum may be related to axonemal abnormalities

Although electron microscopy provides a detailed analysis of ultrastructural abnormalities, this technique is not available in all laboratories. We sought to determine whether certain characteristics of the flagellum as assessed by light microscopy were related to axonemal abnormalities. Forty-one patients with an absence of outer dynein arms (type I), a lack of a central complex (type III) and an absence of peripheral doublets (type IV) were studied. Sperm morphology was scored according to David's modified classification. Flagella with an irregular thickness were classified as being of normal length, short or broken. There were correlations between missing outer dynein arms and abnormal, short or coiled flagellum. Type III patients showed the highest flagellar defects (a short (P = 0.0027) or an absent flagellum (P = 0.011)). Just over 68% of the irregular flagella were short in Type III patients, whereas this value was only 34.5% in type I and 26.4% in type IV (P = 0.002). There was a negative correlation between misassembly and spermatozoa of irregular flagella (r = -0.79; P = 0.019). It is concluded that light microscopy analysis of flagellum abnormalities may help provide a correct diagnosis, identify sperm abnormalities with fertility potentials and outcomes in assisted reproduction technologies and assess the genetic risk.

[ICSI treatment in severe asthenozoospermia]

In the management of asthenozoospermia, the spermogram-spermocytogram plays an important role during diagnosis. It is of major importance to distinguish between necrozoospermia and sperm vitality. An ultrastructural study of spermatozoa is processed in the case of primary infertility without female implication, severe, unexplained and irreversible asthenozoospermia, sperm vitality at least 50 % and normal concentration of spermatozoa. Ultrastructural flagellar abnormalities are numerous and involve most spermatozoa. ICSI provides a suitable solution for patients with sperm flagellar defects to conceive children with their own gametes but the rate of ICSI success may be influenced by the type of flagellar abnormality. Some fertilization and birth rate failures which are related to some flagellar abnormalities might occur.

Effect of polyvinylpyrrolidone on sperm function and early embryonic development following intracytoplasmic sperm injection in human assisted reproduction

The objective here was to review the effects of polyvinylpyrrolidone (PVP) upon sperm function and embryonic development in humans. PVP has been used successfully in intracytoplasmic sperm injection (ICSI) to facilitate the handling and immobilization of sperm for both domestic animals and humans. In our previous reports, PVP solution exists locally in embryos injected during the early developmental period, and also exerts influence over the developmental capacity of such embryos. In other reports, PVP causes significant damage to sperm membranes that can be detected by transmission electron microscopy, and has been associated with chromosomal abnormalities in pregnancy derived from ICSI embryos. In some Japanese clinics, PVP-free media has been used for sperm immobilization in order to optimise safety. Consequently, it is strongly suggested that the success rate of fertilization and clinical pregnancy could be improved by using PVP-free solution for human ICSI. In conclusion, our interpretation of the available data is to perform ICSI without PVP or select a lower concentration of PVP solution in order to reduce safety for pregnancy and children born via ICSI.

[Morphological defects of sperm flagellum implicated in human male infertility]

The assembly of sperm flagella involves specific components and processes that are still poorly defined. Several morphological defects of the different structures that compose the axoneme have been described and associated to human male infertility. These morphological defects can be classified in 15 main categories. Most of them have been associated to consanguinity and/or familial cases, suggesting their genetic origin. However, so far only few genes have been causally involved.

Male factor infertility and ART

For years, the management and treatment of male factor infertility has been 'experience' and not 'evidence' based. Although not evidence-based, current clinical practice involves extensive use of assisted reproductive techniques (ART). Where specific treatments are not indicated or have failed, ART have become popular adjunctive treatments for alleviating male factor infertility. According to the limited evidence available, intrauterine insemination (IUI) may be considered as a first-line treatment in a couple in which the female partner has a normal fertility status and at least 1×10(6) progressively motile spermatozoa are recovered after sperm preparation. If no pregnancy is achieved after 3-6 cycles of IUI, optimized in vitro fertilization (IVF) can be proposed. When less than 0.5×10(6) progressively motile spermatozoa are obtained after seminal fluid processing or sperm are recovered surgically from the testis or epididymis, intracytoplasmic sperm injection (ICSI) should be performed. Although the outcome of no other ART has ever been scrutinized as much before, no large-scale 'macroproblems' have as yet been observed after ICSI. Yet, ICSI candidates should be rigorously screened before embarking on IVF or ICSI, and thoroughly informed of the limitations of our knowledge on the hereditary aspects of male infertility and the safety aspects of ART.

The Sperm Centrosome: Its Role and Significance in Nature and Human Assisted Reproduction

In humans and other non-rodent mammalian species, the sperm's centriole-centrosome complex is an essential component for successful fertilization and serves as template for all centrioles during subsequent cell divisions, embryo development, divisions of most adult somatic cells, as well as in primary cilia formation and functions. Dysfunctions of this complex can be causes for infertility, developmental disorders, and play a role in various adulthood diseases. While assisted reproductive technology (ART) has been able to overcome sperm motility dysfunctions by employing intracytoplasmic sperm injection (ICSI), we currently do not yet have therapies to overcome dysfunctions of the centriole-centrosome complex although several lines of investigations have addressed the causes for centriole-centrosome dysfunctions and implications for sperm aster formation and union of the parental genomes. The present review highlights the importance of the centriole-centrosome complex and its significance for fertilization and embryo development.

Les larges vacuoles des têtes spermatiques sont-elles associées à des altérations du noyau ou de l’acrosome du spermatozoïde ?

Objectifs

Rechercher la présence d’altérations nucléaires ou acrosomiques dans les spermatozoïdes présentant des vacuoles occupant au moins 13 % de la surface de la tête des spermatozoïdes (spermatozoïdes dits de type 3), détectées à l’aide de la technique MSOME (motile sperm organelle morphology examination).

Matériel et méthodes

Notre étude a été effectuée sur des recueils de sperme de 20 hommes infertiles. Une évaluation de l’acrosome par immunomarquage à l’aide d’un anticorps monoclonal antiproacrosine (Mab4D4) a été associée à une détection de la fragmentation de l’ADN par la technique TUNEL. La condensation de la chromatine spermatique a été évaluée par une coloration au bleu d’aniline, et le taux d’aneuploïdie a été déterminé par hybridation in situ en fluorescence (FISH). Une observation des échantillons spermatiques par microscopie électronique à transmission (MET) [sperme entier] et confocale [spermatozoïdes de type 3 isolés] a complété ces analyses. Les résultats ont été comparés entre des spermatozoïdes provenant du sperme entier et des spermatozoïdes de type 3 isolés.

Résultats

Une augmentation significative de la proportion d’acrosomes anormaux a été constatée dans les spermatozoïdes isolés de type 3 par comparaison au sperme entier (77,8 ± 2,49 % vs 70,6 ± 2,62 %). La fragmentation de l’ADN a été observée de manière comparable dans les spermatozoïdes de type 3 et le sperme entier (14,5 ± 3,45 % vs 11,5 ± 1,25%), un défaut de condensation de la chromatine ainsi qu’une augmentation significative du taux d’aneuploïdie ont été retrouvés dans les spermatozoïdes isolés par comparaison à ceux provenant du sperme entier (50,4 ± 3,10 % vs 26,5 ± 2,60 % et 7,8 ± 1,98 % vs 1,3 ± 0,18 %). Les larges vacuoles sont à localisation nucléaire exclusive (MET et microscopie confocale).

Conclusion

Les vacuoles seraient en relation directe avec un défaut de maturation nucléaire survenant au cours de la spermiogenèse.

Successful twin birth following blastocyst culture of embryos derived from the immotile ejaculated spermatozoa from a patient with primary ciliary dyskinesia: a case report

PURPOSE

To describe the ultrastructure of spermatozoa from a patient with complete asthenozoospermia that resulted in live births following blastocyst culture.

MATERIALS AND METHODS

Analyses of spermatozoa from a 36 year old patient were performed using light and electron microscopy. The hypo-osmotic swelling test was used to select spermatozoa for intracytoplasmic sperm injection. Embryos were cultured to the blastocyst stage.

RESULTS

100% of the spermatozoa had dynein arm deficiency with secondary defects varying from 3-17%. Six oocytes were injected; five fertilized normally and one was digynic. All five zygotes formed good quality blastocysts. Three blastocysts were cryopreserved and two blastocysts were transferred. Twin females were born at 37 weeks.

CONCLUSIONS

The hypo-osmotic swelling test can be used to select viable immotile ejaculated spermatozoa from a patient with dynein arm deficiency and can produce excellent fertilization rates and blastocyst development resulting in live births.

[Animal models: Candidate genes for human male infertility]

More than 300 genes necessary for the normal completion of the spermatogenesis have been identified by means of the production of knockout mice. The data cover the whole male reproduction apparatus and thus allow defining candidate genes that could be related to various dysfunctions of human male fertility. Data obtained from mouse models have allowed identifying genetic mutations with loss of function for men with: (i) early meiotic arrest, (ii) maturation arrest of the round spermatid and (iii) morphological anomalies of the spermatozoa. Also numerous Drosophila mutants are models for the knowledge of genes involved in the spermatogenesis. Finally, there are other important models sharing cilia and flagella, and thus, having a structure in common with the sperm flagellum, the axoneme. First, these organisms have allowed the identification of genes involved in human respiratory diseases. But interestingly, these last two years, a great number of human syndromes have been discovered to be related to cilia pathologies, and among them, complex phenotypes including an abnormal spermatogenesis.