Recent advances in the genetics of testicular failure

Syringin alleviates bisphenol A-induced spermatogenic defects and testicular injury by suppressing oxidative stress and inflammation in male zebrafish

Syringin (SRG) is a bioactive principle possessing extensive activities including scavenging of free radicals, inhibition of apoptosis, and anti-inflammatory properties. However, its effects on spermatogenic defects and testicular injury as well as the underlying mechanisms are still unclear. This study aims to investigate the protective effect of SRG on testis damage in zebrafish and explore its potential molecular events. Zebrafish testicular injury was induced by exposure to bisphenol A (BPA) (3000 μg/L) for two weeks. Fish were treated with intraperitoneal injection of SRG at different doses (5 and 50 mg/kg bodyweight) for two more weeks under BPA induction. Subsequently, the testis and sperm were collected for morphological, histological, biochemical and gene expression examination. It was found that the administration of SRG resulted in a significant protection from BPA-caused impact on sperm concentration, morphology, motility, fertility rate, testosterone level, spermatogenic dysfunction and resulted in increased apoptotic and reactive oxygen species' levels. Furthermore, testicular transcriptional profiling alterations revealed that the regulation of inflammatory response and oxidative stress were generally enriched in differentially expressed genes (DEGs) after SRG treatment. Additionally, it was identified that SRG prevented BPA-induced zebrafish testis injury through upregulation of fn1a, krt17, fabp10a, serpina1l and ctss2. These results indicate that SRG alleviated spermatogenic defects and testicular injury by suppressing oxidative stress and inflammation in male zebrafish.

Identification and immuno-infiltration analysis of cuproptosis regulators in human spermatogenic dysfunction

Introduction: Cuproptosis seems to promote the progression of diverse diseases. Hence, we explored the cuproptosis regulators in human spermatogenic dysfunction (SD), analyzed the condition of immune cell infiltration, and constructed a predictive model.

Methods: Two microarray datasets (GSE4797 and GSE45885) related to male infertility (MI) patients with SD were downloaded from the Gene Expression Omnibus (GEO) database. We utilized the GSE4797 dataset to obtain differentially expressed cuproptosis-related genes (deCRGs) between SD and normal controls. The correlation between deCRGs and immune cell infiltration status was analyzed. We also explored the molecular clusters of CRGs and the status of immune cell infiltration. Notably, weighted gene co-expression network analysis (WGCNA) was used to identify the cluster-specific differentially expressed genes (DEGs). Moreso, gene set variation analysis (GSVA) was performed to annotate the enriched genes. Subsequently, we selected an optimal machine-learning model from four models. Finally, nomograms, calibration curves, decision curve analysis (DCA), and the GSE45885 dataset were utilized to verify the predictions’ accuracy.

Results: Among SD and normal controls, we confirmed that there are deCRGs and activated immune responses. Through the GSE4797 dataset, we obtained 11 deCRGs. ATP7A, ATP7B, SLC31A1, FDX1, PDHA1, PDHB, GLS, CDKN2A, DBT, and GCSH were highly expressed in testicular tissues with SD, whereas LIAS was lowly expressed. Additionally, two clusters were identified in SD. Immune-infiltration analysis showed the existing heterogeneity of immunity at these two clusters. Cuproptosis-related molecular Cluster2 was marked by enhanced expressions of ATP7A, SLC31A1, PDHA1, PDHB, CDKN2A, DBT, and higher proportions of resting memory CD4+ T cells. Furthermore, an eXtreme Gradient Boosting (XGB) model based on 5-gene was built, which showed superior performance on the external validation dataset GSE45885 (AUC = 0.812). Therefore, the combined nomogram, calibration curve, and DCA results demonstrated the accuracy of predicting SD.

Conclusion: Our study preliminarily illustrates the relationship between SD and cuproptosis. Moreover, a bright predictive model was developed.

Interaction between apoptosis and autophagy in testicular function

Several processes including oxidative stress, apoptosis, inflammation and autophagy are related to testicular function. Recent studies indicate that a crosstalk between apoptosis and autophagy is essential in regulating testicular function. Autophagy and apoptosis communicate with each other in a complex way, allowing them to work for or against each other in testicular cell survival and death. Several xenobiotics especially endocrine-disrupting chemicals (EDCs) have caused reproductive toxicity because of their potential to modify the rate of autophagy and trigger apoptosis. Therefore, the purpose of the present review was to shed light on how autophagy and apoptosis interact together in the testis.

Update on genetic screening and treatment for infertile men with genetic disorders in the era of assisted reproductive technology

A genetic etiology of male infertility is identified in fewer than 25% of infertile men, while 30% of infertile men lack a clear etiology, resulting in a diagnosis of idiopathic male infertility. Advances in reproductive genetics have provided insights into the mechanisms of male infertility, and a characterization of the genetic basis of male infertility may have broad implications for understanding the causes of infertility and determining the prognosis, optimal treatment, and management of couples. In a substantial proportion of patients with azoospermia, known genetic factors contribute to male infertility. Additionally, the number of identified genetic anomalies in other etiologies of male infertility is growing through advances in whole-genome amplification and next-generation sequencing. In this review, we present an up-to-date overview of the indications for appropriate genetic tests, summarize the characteristics of chromosomal and genetic diseases, and discuss the treatment of couples with genetic infertility by microdissection-testicular sperm extraction, personalized hormone therapy, and in vitro fertilization with pre-implantation genetic testing.

V-Set and Immunoglobulin Domain-Containing 1 (VSIG1), Predominantly Expressed in Testicular Germ Cells, Is Dispensable for Spermatogenesis and Male Fertility in Mice

To elucidate the functional role of V-set and immunoglobulin domain-containing 1 (VSIG1) in spermatogenesis and fertilization, we knocked out (KO) VSIG1 in a mouse embryo using CRISPR/Cas9 (Clustered regularly interspaced short palindromic repeat/CRISPR-associated protein 9) -mediated genome editing. Reverse transcription PCR was performed using cDNA synthesized from VSIG1 KO testis RNA. Although Western blot analysis using a specific antibody to VSIG1 confirmed VSIG1 protein defects in the KO mice, hematoxylin-eosin staining analysis was similar in the KO and wild-type mice. Additionally, computer-assisted sperm analysis and in vitro fertilization experiments were conducted to confirm the activity and fertilization ability of sperm derived from the KO mouse. Mice lacking VSIG1 were viable and had no serious developmental defects. As they got older, the KO mice showed slightly higher weight loss, male mice lacking VSIG1 had functional testes, including normal sperm number and motility, and both male and female mice lacking VSIG1 were fertile. Our results from VSIG1 KO mice suggest that VSIG1 may not play essential roles in spermatogenesis and normal testis development, function, and maintenance. VSIG1 in sperm is dispensable for spermatogenesis and male fertility in mice. As several genes are known to possess slightly different functions depending on the species, the importance and molecular mechanism of VSIG1 in tissues of other species needs further investigation.

Rare missense variant in MSH4 associated with primary gonadal failure in both 46, XX and 46, XY individuals

STUDY QUESTION

Can whole-exome sequencing (WES) reveal a shared pathogenic variant responsible for primary gonadal failure in both male and female patients from a consanguineous family?

SUMMARY ANSWER

Patients with primary ovarian insufficiency (POI) and non-obstructive azoospermia (NOA) were homozygous for the rare missense variant p. S754L located in the highly conserved MSH4 MutS signature motif of the ATPase domain. An oligozoospermic patient was heterozygous for the variant.

WHAT IS KNOWN ALREADY

MSH4 is a meiosis-specific protein expressed at a certain level in the testes and ovaries. Along with its heterodimer partner MSH5, it is responsible for double-strand Holliday junction recognition and stabilization, to ensure accurate chromosome segregation during meiosis. Knockout male and female mice for Msh4 and Msh5 are reportedly infertile due to meiotic arrest. In humans, MSH4 is associated with male and female gonadal failure, with distinct variations in the MutS domain V.

STUDY DESIGN, SIZE, DURATION

This was a retrospective genetics study of a consanguineous family with multiple cases of gonadal failure in both genders. The subject family was recruited in Iran, in 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The proband who is affected by POI, an NOA brother, a fertile sister and their parents were subjected to WES. The discovered variant was validated in these individuals, and the rest of the family was also genotyped by Sanger sequencing. The variant was not detected in 800 healthy Iranian individuals from the Iranome database nor in 30 sporadic NOA and 30 sporadic POI patients. Suggested effect in aberrant splicing was studied by RT-PCR. Moreover, protein homology modeling was used to further investigate the amino acid substitution in silico.

MAIN RESULTS AND THE ROLE OF CHANCE

The discovered variant is very rare and has never been reported in the homozygous state. It occurs in the ATPase domain at Serine 754, the first residue within the highly conserved MutS signature motif, substituting it with a Leucine. All variant effect prediction tools indicated this variant as deleterious. Since the substitution occurs immediately before the Walker B motif at position 755, further investigations based on protein homology were conducted. Considering the modeling results, the nature of the substituted amino acid residue and the distances between p. S754L variation and the residues of the Walker B motif suggested the possibility of conformational changes affecting the ATPase activity of the protein.

LARGE SCALE DATA

We have submitted dbSNP entry rs377712900 to ClinVar under SCV001169709, SCV001169708 and SCV001142647 for oligozoospermia, NOA and POI, respectively.

LIMITATIONS, REASONS FOR CAUTION

Studies in model organisms can shed more light on the role of this variant as our results were obtained by variant effect prediction tools and protein homology modeling.

WIDER IMPLICATIONS OF THE FINDINGS

Identification of variants in meiotic genes should improve genetic counseling for both male and female infertility. Also, as two of our NOA patients underwent testicular sperm extraction (TESE) with no success, ruling out the existence of pathogenic variants in meiotic genes in such patients prior to TESE could prove useful.

STUDY FUNDING/COMPETING INTEREST(S)

This study was financially supported by Royan Institute in Tehran, Iran, and Institut Pasteur in Paris, France. The authors declare no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Comprehensive assessment of a clinic's experience of preimplantation genetic testing by a cumulative rate

OBJECTIVE

This study aimed to investigate the outcomes of patients who had preimplantation genetic testing for chromosomal structural rearrangement (PGT-SR) or for aneuploidy screening (PGT-A) with different indications.

METHODS

This was a retrospective study at a single center. Pregnancy outcomes of all couples who had PGT from 2014 to 2018 were retrospectively analyzed, and the cumulative pregnancy rates (CPR) and the cumulative live birth/ongoing pregnancy rate (CLB/OPR) per patient with at least one transfer cycle were calculated.

RESULTS

A total of 313 PGT-SR cycles of 255 patients, 22 PGT-sexing cycles of 20 patients, and 190 PGT-A cycles of 168 patients were performed during the period. In PGT-SR, the overall CPR and the CLB/OPR were 68.04% and 59.79%, respectively. In PGT-A, the CPR and CLB/OPR were 67.52% and 58.12%, respectively. We also found that the CPR (93.75%) and CLB/OPR (87.50%) were highest in patients for PGT-sexing with a diagnosis of Y chromosomal microdeletion. In addition, we discovered a significant trend that aneuploidy rate significantly increased with maternal age (p = 0.000) in PGT-A population. No significant difference was found in the mosaicism rate or clinical outcomes among the age groups. Similarly, the significance was absent in the PGT-SR population.

CONCLUSION

We reviewed the CPR and CLB/OPR for different indications since the 24-chromosome technique has been applied in the clinical setting for 4 years in our center. We hope that our results will provide some pointed guidance and a new perspective on outcomes for PGT in certain patients and clinicians.

MALDI-IMS combined with shotgun proteomics identify and localize new factors in male infertility

In situ proteomics of male infertility.

Spermatogenesis is a complex multi-step process involving intricate interactions between different cell types in the male testis. Disruption of these interactions results in infertility. Combination of shotgun tissue proteomics with MALDI imaging mass spectrometry is markedly potent in revealing topological maps of molecular processes within tissues. Here, we use a combinatorial approach on a characterized mouse model of hormone induced male infertility to uncover misregulated pathways. Comparative testicular proteome of wild-type and mice overexpressing human P450 aromatase (AROM+) with pathologically increased estrogen levels unravels gross dysregulation of spermatogenesis and emergence of pro-inflammatory pathways in AROM+ testis. In situ MS allowed us to localize misregulated proteins/peptides to defined regions within the testis. Results suggest that infertility is associated with substantial loss of proteomic heterogeneity, which define distinct stages of seminiferous tubuli in healthy animals. Importantly, considerable loss of mitochondrial factors, proteins associated with late stages of spermatogenesis and steroidogenic factors characterize AROM+ mice. Thus, the novel proteomic approach pinpoints in unprecedented ways the disruption of normal processes in testis and provides a signature for male infertility.

Testicular leiomyoma and spermatogenic failure syndrome in a seabass from broodstock

Testicular leiomyomas and gonadal dysfunctions are not commonly reported in teleost and particularly in broodstock fish. In the present work, a testicular leiomyoma related to an unusual case of spermatogenic failure syndrome, in a broodstock seabass coming from an Italian aquaculture farm, is reported. At gross pathology, the circumscribed neoplasia showed several white nodular masses, originating from the gonad, deforming the anatomo-physiological shape. From light microscopy, the presence of neoplastic tissue islands with spindle cells with a whirling pattern and the low presence of connective tissue were evident and originated from smooth muscle cells. Seminiferous tubules showed severe azoospermia with the absence of sperm cells even closer to the neoplastic area. Immunohistochemical analysis was positive for alpha-SMA, desmin and vimentin but negative for S-100, confirming a diagnosis of leiomyoma. This is the first report of spermatogenic failure syndrome associated with a testicular leiomyoma in fish from broodstock. More efforts should be made in studying broodstock fish pathologies related to fish maintenance and hormonal treatments that could economically affect aquaculture production.

Fertility Relevance Probability Analysis Shortlists Genetic Markers for Male Fertility Impairment

Impairment of male fertility is one of the major public health issues worldwide. Nevertheless, genetic causes of male sub- and infertility can often only be suspected due to the lack of reliable and easy-to-use routine tests. Yet, the development of a marker panel is complicated by the large quantity of potentially predictive markers. Actually, hundreds or even thousands of genes could have fertility relevance. Thus, a systematic method enabling a selection of the most predictive markers out of the many candidates is required. As a criterion for marker selection, we derived a gene-specific score, which we refer to as fertility relevance probability (FRP). For this purpose, we first categorized 2,753 testis-expressed genes as either candidate markers or non-candidates, according to phenotypes in male knockout mice. In a parallel approach, 2,502 genes were classified as candidate markers or non-candidates based on phenotypes in men. Subsequently, we conducted logistic regression analyses with evolutionary rates of genes (dN/dS), transcription levels in testis relative to other organs, and connectivity of the encoded proteins in a protein-protein interaction network as covariates. In confirmation of the procedure, FRP values showed the expected pattern, thus being overall higher in genes with known relevance for fertility than in their counterparts without corresponding evidence. In addition, higher FRP values corresponded with an increased dysregulation of protein abundance in spermatozoa of 37 men with normal and 38 men with impaired fertility. Present analyses resulted in a ranking of genes according to their probable predictive power as candidate markers for male fertility impairment. Thus, AKAP4, TNP1, DAZL, BRDT, DMRT1, SPO11, ZPBP, HORMAD1, and SMC1B are prime candidates toward a marker panel for male fertility impairment. Additional candidate markers are DDX4, SHCBP1L, CCDC155, ODF1, DMRTB1, ASZ1, BOLL, FKBP6, SLC25A31, PRSS21, and RNF17. FRP inference additionally provides clues for potential new markers, thereunder TEX37 and POU4F2. The results of our logistic regression analyses are freely available at the PreFer Genes website (https://prefer-genes.uni-mainz.de/).

Stem cell-based therapies for fertility preservation in males: Current status and future prospects

With the decline in male fertility in recent years, strategies for male fertility preservation have received increasing attention. In this study, by reviewing current treatments and recent publications, we describe research progress in and the future directions of stem cell-based therapies for male fertility preservation, focusing on the use of spermatogonial stem cells (SSCs), SSC niches, SSC-based testicular organoids, other stem cell types such as mesenchymal stem cells, and stem cell-derived extracellular vesicles. In conclusion, a more comprehensive understanding of the germ cell microenvironment, stem cell-derived extracellular vesicles, and testicular organoids will play an important role in achieving male fertility preservation.

Male infertility and genitourinary birth defects: there is more than meets the eye

Male factor infertility is a significant problem present in up to 50% of infertile couples. The relationship between male infertility and systemic disease is of significant interest, and emerging evidence suggests a relationship between male infertility and male genitourinary (GU) birth defects (cryptorchidism, hypospadias, ambiguous genitalia, and congenital anomalies of the kidney and urinary tract). Many of these birth defects are treated in isolation by busy urologists without acknowledgment that these may be related to more global syndromic conditions. Conversely, geneticists and nonurologists who treat variable systemic phenotypes may overlook GU defects, which are indeed related conditions. Many of these defects are attributed to copy number variants dosage-sensitive genes due to chromosome microdeletions or microduplications. These variants are responsible for disease phenotypes seen in the general population. The copy number variants described in this review are syndromic in some cases and responsible for both GU birth defects as well as other systemic phenotypes. This review highlights the emerging evidence between these birth defects, male infertility, and other systemic conditions.

Deletion of inositol polyphosphate 4-phosphatase type-II B affects spermatogenesis in mice

Inositol polyphosphate-4-phosphatase type II (INPP4B) is a dual-specificity phosphatase that acts as a tumor suppressor in multiple cancers. INPP4B dephosphorylates phospholipids at the 4th position of the inositol ring and inhibits AKT and PKC signaling by hydrolyzing of PI(3,4)P2 and PI(4,5)P2, respectively. INPP4B protein phosphatase targets include phospho-tyrosines on Akt and phospho-serine and phospho-threonine on PTEN. INPP4B is highly expressed in testes, suggesting its role in testes development and physiology. The objective of this study was to determine whether Inpp4b deletion impacts testicular function in mice. In testis, Inpp4b expression was the highest in postmeiotic germ cells in both mice and men. The testes of Inpp4b knockout male mice were significantly smaller compared to the testes of wild-type (WT) males. Inpp4b^-/- males produced fewer mature sperm cells compared to WT, and this difference increased with age and high fat diet (HFD). Reduction in early steroidogenic enzymes and luteinizing hormone (LH) receptor gene expression was detected, although androgen receptor (AR) protein level was similar in WT and Inpp4b^-/- testes. Germ cell apoptosis was significantly increased in the knockout mice, while expression of meiotic marker γH2A.X was decreased. Our data demonstrate that INPP4B plays a role in maintenance of male germ cell differentiation and protects testis functions against deleterious effects of aging and high fat diet.

New insights into the potential mechanisms of spermatogenic failure in patients with idiopathic azoospermia

Idiopathic azoospermia (IA) refers to azoospermia without a clear aetiology. Due to the unclear aetiology and pathological mechanism of IA, there is no effective treatment for IA. The development of assisted reproductive and microsperm extraction technologies has brought hope to patients with IA with fertility problems. However, there are still many patients with IA whose testes lack healthy sperm, causing infertility. Therefore, it is key to identify how testicular spermatogenic failure can be reversed to promote spermatogenesis in patients with IA to resolve fertility problems; these goals are a great challenge in reproductive medicine. The underlying genetic factors seem to be important pathological factors of IA. Understanding the role of genetic factors in the pathological mechanism of spermatogenic failure in patients with IA is of great value for future studies and treatments and is also an important reference for the reproductive health of males and their offspring. A method combining sequencing technology and bioinformatics analysis is an important means to understand the genetic pathological mechanisms. We used bioinformatics analysis to study the public human IA dataset. We found that the pathogenic mechanism of IA may be related to abnormal ciliary structure and function and disrupted RNA metabolism in spermatogenic cells. Disrupted m6A regulation of spermatogenesis may be an important pathological mechanism of IA and warrants attention. Finally, we screened for key genes and potential therapeutic drugs to determine future research directions.

A rare karyotype of nonmosaic isodicentric (Y) (p11.31) with azoospermia and short stature

Chromosome aberration is one of the common causes of male infertility. Isodicentric chromosome is a chromosomal aberration in which two arms of a chromosome are identical in morphology and genetics and connected by two centromeres. We firstly reported a case of infertile male with nonmosaic 46, X, idic (Y) (qter-p11.31::p11.31-qter) but with the sex-determining region Y (SRY). The broken site is the chromosome Y (p11.31). The patients' clinical phenotype was azoospermia and short stature. Fluorescence in situ hybridisation (FISH), chromosomal microarray comparative genomic hybridisation (array CGH) and related molecular analysis were performed. Azoospermia of this case may be caused by the abnormal chromosome structure, which leads to abnormal chromosome synapsis in spermatogenesis. Loss of genes in PAR1 and gain of genes copies in azoospermia factor (AZF) region on the Y chromosome may also contribute to the pathogenesis of azoospermia.

Reproductive outcomes of 3 infertile males with XYY syndrome: Retrospective case series and literature review

The aim of this study is to evaluate the pregnancy outcomes of males with a 47, XYY karyotype following assisted reproductive treatment.A retrospective study was performed using data from infertile men with 47, XYY at a center for reproductive medicine in 2004 to 2017. Of the 19,842 infertile males treated, a total of 21 showed the 47, XYY karyotype and were included in the present study. Clinical variables were collected. Three men were under treatment with their partner before either in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI).The incidence of 47, XYY in infertile men is 1/945 (21/19842). Most men are azoospermic or severely oligospermic. Three men and their partners underwent IVF or ICSI treatment with fresh ejaculate samples. The fertilization rate was 52.94% to 83.33%. The embryo cleavage rate was 50% to 90%. One man had abnormal sex hormonal levels and his partner had no clinical pregnancy. The other 2 couples had healthy baby boys.Live spermatozoa can be gathered and fertility is possible for infertile males with 47, XYY syndrome when IVF or ICSI treatment is used. It is recommended that genetic counseling is provided in such cases.

Chromosome 1q21 translocation and spermatogenesis failure: Two case reports and review of the literature

RATIONALE

For the carriers of chromosome reciprocal translocation, the reason why some are fertile and others are infertile remains unclear. Here, we describe 2 patients who are carriers of chromosome 1q21 translocation with azoospermia.

PATIENT CONCERNS

A 29-year-old male and a 33-year-old male presented at the clinic with a diagnosis of infertility.

DIAGNOSIS

Both patients with azoospermia were diagnosed with Routine semen analysis, cytogenetic diagnosis and detection of serum reproductive hormones. The karyotype results of 2 patients were 46,XY,t(1;17)(q21;q23) and 46,XY,t(1;10)(q21;p12), respectively.

INTERVENTIONS

After genetic counseling and informed consent, 1 patient (Case 2) chose microsopic testicular sperm extraction (micro-TESE).

OUTCOMES

After micro-TESE, no sperm was found for the patient. Finally, both patients chose clinical treatment through artificial insemination with donor sperm.

LESSONS

These outcomes suggest that breakpoint at 1q21 should be paid attention by physician in genetic counseling, may harbor some genes associated with spermatogenesis, and deserves further be studied on the function of related genes.

Potential use of stem cells for fertility preservation

BACKGROUND

Infertility and gonadal dysfunction can result from gonadotoxic therapies, environmental exposures, aging, or genetic conditions. In men, non-obstructive azoospermia (NOA) results from defects in the spermatogenic process that can be attributed to spermatogonial stem cells (SSC) or their niche, or both. While assisted reproductive technologies and sperm banking can enable fertility preservation (FP) in men of reproductive age who are at risk for infertility, FP for pre-pubertal patients remains experimental. Therapeutic options for NOA are limited. The rapid advance of stem cell research and of gene editing technologies could enable new FP options for these patients. Induced pluripotent stem cells (iPSC), SSC, and testicular niche cells, as well as mesenchymal stromal cells (aka medicinal signaling cells, MSCs), have been investigated for their potential use in male FP strategies.

OBJECTIVE

Here, we review the benefits and challenges for three types of stem cell-based approaches under investigation for male FP, focusing on the role that promising sources of MSC derived from human umbilical cord, specifically human umbilical cord perivascular cells (HUCPVC), could fulfill. These approaches are as follows: 1. isolation and ex vivo expansion of autologous SSC for in vivo transplantation or in vitro spermatogenesis; 2. in vitro differentiation toward germ cell and testicular somatic cell lineages using autologous SSC, or stem cells such iPSC or MSC; and 3. protection or regeneration of the spermatogenic niche after gonadotoxic insults in vivo.

CONCLUSION

Our studies suggest that HUCPVC are promising sources of cells that could be utilized in multiple aspects of male FP strategies.

Seminiferous tubule molecular imaging for evaluation of male fertility: Seeing is believing

The proper assessment of male fertility is essential for diagnosing and treating male infertility. Currently, spermiogram and Johnsen testicular biopsy score counts are used to assess male fertility. However, spermiogram is not a suitable option for non-obstructive azoospermia patients, and Johnsen testicular biopsy scores only represent localized and not the overall spermatogenesis. Whole-mount staining was a novel method for evaluating protein expression in the tissue. Thus, we explored its application in human seminiferous tubules. Testicular biopsies from 57 azoospermia patients were categorized as obstructive azoospermia (OA), maturation arrest (MA) and Sertoli-cells only syndrome (SCOS). We performed whole-mount staining of their seminiferous tubules and evaluated the spermatogonial stem cells (SSCs), differentiated spermatogonia (SG), spermatocytes (SPC) and spermatids (SD) with their respective markers (GFRA1, CD117, SYCP3, and PNA) to assess fertility. GFRA1, CD117, SYCP3, and PNA were not expressed in SCOS patients, whereas all of them were detected in OA patients. In MA patients with arrested spermatogenesis at the SPC stage, GFRA1, CD117, and SYCP3, but not PNA were expressed in the seminiferous tubules. In MA patients with arrested spermatogenesis at the spermatogonia stage, only GFRA1 was expressed in the seminiferous tubules. These results were consistent with the Johnsen testicular biopsy score counts except for one patient, where although only Sertoli cells were indicated by the score, SSCs were also detected in the whole-mounts. Collectively, whole-mount staining could be used to analyze the inherent spermatogenesis of seminiferous tubules through staining of germ cells at different stages. It offers a more accurate and promising faster method for assessing male fertility compared with traditional biopsy screening. And it could have potential value for the clinical purpose for male fertility management.

Interstitial Deletion of 5q22.2q23.1 Including APC and TSSK1B in a Patient with Adenomatous Polyposis and Asthenoteratozoospermia

Interstitial 5q22 deletions are relatively rare and usually represented by severe clinical features such as developmental delay and growth retardation. Here, we report a 23-year-old male patient, referred to our laboratory for genetic confirmation of possible familial adenomatous polyposis. MLPA and the subsequent array CGH identified an approximately 8-Mb-sized deletion in the 5q22.2q23.1 locus. Further analysis of the deleted region and the genes within suggested a possible role for the TSSK1B (testis-specific serine/threonine kinase 1) gene in the patient's reproductive capacity. Semen analysis confirmed that the patient's reproductive capability was impaired, and that he suffered from asthenoteratozoospermia. Analysis of the azoospermia factor region on the Y chromosome revealed no microdeletions. Further sequencing tests could not find an alternative explanation for the patient's infertility. This case demonstrates a possible role of TSSK1B in male reproduction.

Early detection of Y chromosome microdeletions in infertile men is helpful to guide clinical reproductive treatments in southwest of China

The microdeletions of azoospermia factor (AZF) genes in Y chromosome are greatly associated with male infertility, which is also known as the second major genetic cause of spermatogenetic failure. Accumulating studies demonstrate that the different type of AZF microdeletions in patients reflect different clinical manifestations. Therefore, a better understanding of Y chromosome microdeletions might have broad implication for men health. In this study, we sought to determine the frequency and the character of different Y chromosome microdeletion types in infertile men in southwest of China.In total, 1274 patients with azoospermia and oligozoospermia were recruited in southwest of China and screening for Y chromosome microdeletions in AZF regions by multiplex polymerase chain reaction.The incidence of AZF microdeletions in southwest of China is 12.87%, which is higher than the national average. Further investigations unveiled that azoospermia factor c (AZFc) is the most frequent type of all the AZF microdeletions. Additionally, the number and also the quality of sperm in patients with AZFc microdeletion is decreasing with the age. Therefore, it is conceivable that the early testing for Y chromosome microdeletions in infertile men is crucial for fertility guidance.The early detection of Y chromosome microdeletions in infertile men can not only clearly explain the etiology of oligzoospermia and azoospermia, but also help for the clinical management of both infertile man and his future male offspring.

Chromosome positioning and male infertility: it comes with the territory

The production of functional spermatozoa through spermatogenesis requires a spatially and temporally highly regulated gene expression pattern, which in case of alterations, leads to male infertility. Changes of gene expression by chromosome anomalies, gene variants, and epigenetic alterations have been described as the main genetic causes of male infertility. Recent molecular and cytogenetic approaches have revealed that higher order chromosome positioning is essential for basic genome functions, including gene expression. This review addresses this issue by exposing well-founded evidences which support that alterations on the chromosome topology in spermatogenetic cells leads to defective sperm function and could be considered as an additional genetic cause of male infertility.

Gene alterations and expression spectrum of SPATA33 in nonobstructive azoospermic Iranian men

Genetic abnormalities have been considered a significant cause of male infertility. Increased expression of SPATA33 during the first wave of spermatogenesis indicates its possible association with the meiotic process. The aim of the current study was to investigate the genetic variations in the SPATA33 gene and its expression in patients with nonobstructive azoospermia (NOA). A total of 100 Iranian NOA men with idiopathic infertility were taken as the case group. The control group comprised 100 fertile men who had at least one child. The presence of nucleotide variations was analyzed in both groups using the standard polymerase chain reaction (PCR) sequencing technique. For mRNA and protein expression studies, testicular biopsy specimens from 27 patients were subdivided into three groups: nine obstructive azoospermic patients with hypospermatogenesis as control; nine maturation arrest (MA) and nine Sertoli cell-only syndromes (SCOS) as case groups. The expression of SPATA33 at both mRNA and protein levels was compared among these three groups using the reverse transcription PCR technique, the realtime-PCR technique, and immunohistochemistry. Mutation analysis of the SPATA33 gene revealed five nucleotide changes among the population studied. All but one showed no significant differences between the groups. The genotype distributions of rs112536073A > T in the transcription factor binding site region with heterozygote and homozygote genotypes were significantly different ( p < 0.05) between the two groups. More heterozygotes of this polymorphism were observed in patients, whereas more homozygotes were detected in controls. Accordingly, the current study illustrated that alterations in SPATA33 gene, at least those found in this study, may not impair spermatogenesis in patients with NOA. Reduction of gene expression at the level of mRNA in patients with SCOS can be interpreted by the absence of germ cells in the testicular tissue of these patients.

Clinical features of carriers of reciprocal chromosomal translocations involving chromosome 2: report of nine cases and review of the literature

OBJECTIVE

To explore the clinical features of carriers of chromosome 2 translocations, enabling informed genetic counseling of these patients.

MATERIALS AND METHODS

Eighty-two male carriers of a translocation who were infertile or receiving fertility counseling were recruited. Cytogenetic analyses were performed using G-banding. A search of PubMed was performed to determine whether the identified translocations on chromosome 2 are involved in male infertility. The relationships of translocation breakpoints with male infertility and recurrent pregnancy loss were analyzed.

RESULTS

Of the 82 translocation carriers, 9 (11%) were carriers of a chromosome 2 translocation. Four cases had oligozoospermia or infertility, while five had normal semen. In an analysis of the literature, 55 patients who were carriers of chromosome 2 translocations were also reviewed. Breakpoints at 2p13 and 2q31 were observed in six patients each, and were the most common. Breakpoints at 2p23, 2p13, 2p11.2, 2q31, and 2q37 were associated to both pre-gestational and gestational infertility, while other breakpoints were associated with gestational infertility.

CONCLUSIONS

All breakpoints at chromosome 2 were correlated with gestational infertility. Carriers of chromosome 2 translocations should therefore receive counseling to continue with natural conception and use of different technologies available via assisted reproductive technology, such as preimplantation genetic diagnosis.

Deliverable transgenics & gene therapy possibilities for the testes

Male infertility and hypogonadism are clinically prevalent conditions with a high socioeconomic burden and are both linked to an increased risk in cardiovascular-metabolic diseases and earlier mortality. Therefore, there is an urgent need to better understand the causes and develop new treatments for these conditions that affect millions of men. The accelerating advancement in gene editing and delivery technologies promises improvements in both diagnosis as well as affording the opportunity to develop bespoke treatment options which would both prove beneficial for the millions of individuals afflicted with these reproductive disorders. In this review, we summarise the systems developed and utilised for the delivery of gene therapy and discuss how each of these systems could be applied for the development of a gene therapy system in the testis and how they could be of use for the future diagnosis and repair of common male reproductive disorders.

Genetics of the human Y chromosome and its association with male infertility

The human Y chromosome harbors genes that are responsible for testis development and also for initiation and maintenance of spermatogenesis in adulthood. The long arm of the Y chromosome (Yq) contains many ampliconic and palindromic sequences making it predisposed to self-recombination during spermatogenesis and hence susceptible to intra-chromosomal deletions. Such deletions lead to copy number variation in genes of the Y chromosome resulting in male infertility. Three common Yq deletions that recur in infertile males are termed as AZF (Azoospermia Factor) microdeletions viz. AZFa, AZFb and AZFc. As estimated from data of nearly 40,000 Y chromosomes, the global prevalence of Yq microdeletions is 7.5% in infertile males; however the European infertile men are less susceptible to Yq microdeletions, the highest prevalence is in Americans and East Asian infertile men. In addition, partial deletions of the AZFc locus have been associated with infertility but the effect seems to be ethnicity dependent. Analysis of > 17,000 Y chromosomes from fertile and infertile men has revealed an association of gr/gr deletion with male infertility in Caucasians and Mongolian men, while the b2/b3 deletion is associated with male infertility in African and Dravidian men. Clinically, the screening for Yq microdeletions would aid the clinician in determining the cause of male infertility and decide a rational management strategy for the patient. As these deletions are transmitted to 100% of male offspring born through assisted reproduction, testing of Yq deletions will allow the couples to make an informed choice regarding the perpetuation of male infertility in future generations. With the emerging data on association of Yq deletions with testicular cancers and neuropsychiatric conditions long term follow-up data is urgently needed for infertile men harboring Yq deletions. If found so, the information will change the current the perspective of androgenetics from infertility and might have broad implication in men health.

Next-generation sequencing for patients with non-obstructive azoospermia: implications for significant roles of monogenic/oligogenic mutations

Azoospermia affects up to 1% of adult men. Non-obstructive azoospermia is a multifactorial disorder whose molecular basis remains largely unknown. To date, mutations in several genes and multiple submicroscopic copy-number variations (CNVs) have been identified in patients with non-obstructive azoospermia. The aim of this study was to clarify the contribution of nucleotide substitutions in known causative genes and submicroscopic CNVs in the genome to the development of non-obstructive azoospermia. To this end, we conducted sequence analysis of 25 known disease-associated genes using next-generation sequencing and genome-wide copy-number analysis using array-based comparative genomic hybridization. We studied 40 Japanese patients with idiopathic non-obstructive azoospermia. Functional significance of molecular alterations was assessed by in silico analyses. As a result, we identified four putative pathogenic mutations, four rare polymorphisms possibly associated with disease risk, and four probable neutral variants in 10 patients. These sequence alterations included a heterozygous splice site mutation in SOHLH1 and a hemizygous missense substitution in TEX11, which have been reported as causes of non-obstructive azoospermia. Copy-number analysis detected five X chromosomal or autosomal CNVs of unknown clinical significance, in addition to one known pathogenic Y chromosomal microduplication. Five patients carried multiple molecular alterations. The results indicate that monogenic and oligogenic mutations, including those in SOHLH1 and TEX11, account for more than 10% of cases of idiopathic non-obstructive azoospermia. Furthermore, this study suggests possible contributions of substitutions in various genes as well as submicroscopic CNVs on the X chromosome and autosomes to non-obstructive azoospermia, which require further validation.

A report of nine cases and review of the literature of infertile men carrying balanced translocations involving chromosome 5

Background

Balanced translocations may cause the loss of genetic material at the breakpoints and may result in failure of spermatogenesis. However, carriers of reciprocal translocation may naturally conceive. Genetic counseling of male carriers of translocations remains challenging. This study explores the clinical features of carriers of chromosome 5 translocations, enabling informed genetic counseling of these patients.

Results

Of 82 translocation carriers, 9 (11%) were carriers of a chromosome 5 translocation. One case had azoospermia, while three cases had experienced recurrent spontaneous abortions, two cases had each experienced stillbirth, and three cases produced a phenotypically normal child confirmed by amniocentesis. A literature review identified 106 patients who carried chromosome 5 translocations. The most common chromosome 5 translocation was t(4,5), observed in 13 patients. Breakpoint at 5p15 was observed in 11 patients. All breakpoints at chromosome 5 were associated with gestational infertility.

Conclusion

In genetic counseling, physicians should consider chromosome 5 and its breakpoints. Carriers of chromosome 5 translocations may continue with natural conception or use assisted reproductive technologies, such as preimplantation genetic diagnosis.

Testicular organoids: a new model to study the testicular microenvironment in vitro?

BACKGROUND

In recent decades, a broad range of strategies have been applied to model the testicular microenvironment in vitro. These models have been utilized to study testicular physiology and development. However, a system that allows investigations into testicular organogenesis and its impact in the spermatogonial stem-cell (SSC) niche in vitro has not been developed yet. Recently, the creation of tissue-specific organ-like structures called organoids has resurged, helping researchers to answer scientific questions that previous in vitro models could not help to elucidate. So far, a small number of publications have concerned the generation of testicular organoids and their application in the field of reproductive medicine and biology.

OBJECTIVE AND RATIONALE

Here, we aim to elucidate whether testicular organoids might be useful in answering current scientific questions about the regulation and function of the SSC niche as well as germ cell proliferation and differentiation, and whether or not the existing in vitro models are already sufficient to address them. Moreover, we would like to discuss how an organoid system can be a better solution to address these prominent scientific problems in our field, by the creation of a rationale parallel to those in other areas where organoid systems have been successfully utilized.

SEARCH METHODS

We comprehensively reviewed publications regarding testicular organoids and the methods that most closely led to the formation of these organ-like structures in vitro by searching for the following terms in both PubMed and the Web of Science database: testicular organoid, seminiferous tubule 3D culture, Sertoli cell 3D culture, testicular cord formation in vitro, testicular morphogenesis in vitro, germ cell 3D culture, in vitro spermatogenesis, testicular de novo morphogenesis, seminiferous tubule de novo morphogenesis, seminiferous tubule-like structures, testicular in vitro model and male germ cell niche in vitro, with no restrictions to any publishing year. The inclusion criteria were based on the relation with the main topic (i.e. testicular organoids, testicular- and seminiferous-like structures as in vitro models), methodology applied (i.e. in vitro culture, culture dimensions (2D, 3D), testicular cell suspension or fragments) and outcome of interest (i.e. organization in vitro). Publications about grafting of testicular tissue, germ-cell transplantation and female germ-cell culture were excluded.

OUTCOMES

The application of organoid systems is making its first steps in the field of reproductive medicine and biology. A restricted number of publications have reported and characterized testicular organoids and even fewer have denominated such structures by this method. However, we detected that a clear improvement in testicular cell reorganization is recognized when 3D culture conditions are utilized instead of 2D conditions. Depending on the scientific question, testicular organoids might offer a more appropriate in vitro model to investigate testicular development and physiology because of the easy manipulation of cell suspensions (inclusion or exclusion of a specific cell population), the fast reorganization of these structures and the controlled in vitro conditions, to the same extent as with other organoid strategies reported in other fields.

WIDER IMPLICATIONS

By way of appropriate research questions, we might use testicular organoids to deepen our basic understanding of testicular development and the SSC niche, leading to new methodologies for male infertility treatment.

Molecular‑cytogenetic study of de novo mosaic karyotype 45,X/46,X,i(Yq)/46,X,idic(Yq) in an azoospermic male: Case report and literature review

The present study describes a 36‑year‑old male with the 45,X/46,X,i(Yq)/46,X,idic(Yq) karyotype, who suffered from azoospermia attributed to maturation arrest of the primary spermatocyte. To the best of our knowledge, this rare karyotype has not yet been reported in the literature. The results of detailed molecular‑cytogenetic studies of isodicentric (idic)Y chromosomes and isochromosome (iso)Y, which are identified in patient with complex mosaic karyotypes, are presented. The presence of mosaicism of the three cell lines 45,X, 46,X,i(Yq) and 46,X,idic(Yq) may be a contributing factor for spermatogenic failure, in addition to the instability of iso/idic Y chromosomes to pass the spermatogenesis process. Possible mechanisms of the formation of the mosaic karyotype and karyotype‑phenotype correlations are discussed. The current study highlights that routine karyotype analysis and fluorescent in situ hybridization‑based technology are more useful in detecting mosaic chromosomal abnormality, predicting the clinical features of patients during genetic counseling and improving artificial reproductive technologies.

AZFa Microdeletions: Occurrence in Chinese Infertile Men and Novel Deletions Revealed by Semiconductor Sequencing

OBJECTIVE

To evaluate the frequency of azoospermia factor (AZFa) microdeletions among infertile men and establish a new high-throughput sequencing method to detect novel deletion types.

MATERIALS AND METHODS

A total of 3731 infertile men were included. Karyotype analysis was performed using G-band staining of peripheral blood lymphocytes. Polymerase chain reaction (PCR) amplification using specific sequence-tagged sites (STS) was performed to screen for AZF region microdeletions of the Y chromosome. A novel semiconductor sequencing method was established to detect high-resolution AZFa microdeletions.

RESULTS

Of 3731 infertile men, 341 (9.14%) had microdeletions in AZFa, AZFb, or AZFc. Thirteen of these (3.81%) had a deletion in the AZFa region (mean age: 27.3 ± 4 years, range: 22-34), which included 12 subjects with a normal karyotype (46, XY) and 1 with Klinefelter syndrome (47, XXY). Four of 10 subjects with complete AZFa microdeletions (sY86 and sY84 loss) underwent semiconductor sequencing. They all had DNA sequence deletions from nt 14469266 to 15195932, whereas their fathers had no deletions. One subject with partial AZFa microdeletion (sY86 loss) and his father underwent semiconductor sequencing and STS-PCR analysis. The same deletion (sY86 loss with DNA sequence deletion from nt 14469266 to 14607672) was identified in both subjects. Forty sperm donators and 50 infertile men showed no AZFa microdeletions by either method.

CONCLUSION

AZFa deletions are present at a low frequency in men with azoospermia or oligozoospermia. Novel sequencing methods can be used for these patients to reveal high-resolution AZFa microdeletions.

Induced pluripotent stem cell generation from a man carrying a complex chromosomal rearrangement as a genetic model for infertility studies

Despite progress in human reproductive biology, the cause of male infertility often remains unknown, due to the lack of appropriate and convenient in vitro models of meiosis. Induced pluripotent stem cells (iPSCs) derived from the cells of infertile patients could provide a gold standard model for generating primordial germ cells and studying their development and the process of spermatogenesis. We report the characterization of a complex chromosomal rearrangement (CCR) in an azoospermic patient, and the successful generation of specific-iPSCs from PBMC-derived erythroblasts. The CCR was characterized by karyotype, fluorescence in situ hybridization and oligonucleotide-based array-comparative genomic hybridization. The CCR included five breakpoints and was caused by the inverted insertion of a chromosome 12 segment into the short arm of one chromosome 7 and a pericentric inversion of the structurally rearranged chromosome 12. Gene mapping of the breakpoints led to the identification of a candidate gene, SYCP3. Erythroblasts from the patient were reprogrammed with Sendai virus vectors to generate iPSCs. We assessed iPSC pluripotency by RT-PCR, immunofluorescence staining and teratoma induction. The generation of specific-iPSCs from patients with a CCR provides a valuable in vitro genetic model for studying the mechanisms by which chromosomal abnormalities alter meiosis and germ cell development.

Single gene defects leading to sperm quantitative anomalies

Azoospermia, defined by the absence of sperm in the ejaculate, is estimated to affect up to 1% of men in the general population. Assisted reproductive technologies have revolutionized the treatment of infertility, and some azoospermic men, those with a post-meiotic defect, can conceive following the use of viable spermatoza recovered from testicular or epididymal biopsies. Although male infertility is a multifactorial disease, it is believed that genetic factors are predominant in the etiology of azoospermia and severe oligozoospermia. Despite that assumption, substantiated by the high number of infertile knockout (KO) mice and the even higher number of genes expressed essentially in the testis, little is known about the pathophysiology of reduced sperm production, its primary causes or the genetic and epigenetic consequences for the gamete and the future conceptus. The identification of genetic abnormalities is therefore paramount to understand spermatogenesis, to adopt the best course of action for the patient and to provide adequate genetic counseling. We provide here a review of the recent literature on the genetics of azoospermia and oligozoospermia, focusing on defects directly altering sperm production. New sequencing technologies are contributing to the rapid evolution of the recent field of infertility genetics.

Decreased Sperm Motility Retarded ICSI Fertilization Rate in Severe Oligozoospermia but Good-Quality Embryo Transfer Had Achieved the Prospective Clinical Outcomes

INTRODUCTION

Spermatozoa motility is the critical parameter to affect the treatment outcomes during assisted reproductive technologies (ART), but its reproductive capability remains a little informed in condition of severe male factor infertility. This retrospective cohort study aimed to evaluate the effects of reduced sperm motility on the embryological and clinical outcomes in intra-cytoplasmic sperm injection (ICSI) treatment of severe oligozoospermia.

PATIENTS AND METHODS

966 cycles (812 couples) of severe oligozoospermia diagnosed by spermatozoa count ≤ 5 × 106/mL and motile spermatozoa ≤ 2 × 106/mL were divided into four groups in according to the number of motile spermatozoa in one ejaculate on the day of oocyte retrieval (Group B-E). The control (Group A) was 188 cycles of moderate oligozoospermia with spermatozoa count > 5 × 106/mL and motile spermatozoa > 2 × 106/mL. All female partners were younger than 35 years of age. Logistic regression analyzed embryological outcomes (the rates of fertilization, cleavage and good-quality embryo) and clinical outcomes (the rates of pregnancy, implantation, early miscarriage and live birth). Quality of embryo transfer (ET) was divided into three classes as continuous factor to test the effects of embryo quality on clinical outcomes.

RESULTS

The reduction in the number of motile sperm in four groups of severe oligozoospermia gave rise to comparable inability of the fertilization (p < 0.001) and a decreased rate of good-quality embryo at Day 3 (p < 0.001) by compared to the control. The cleavage rate of the derived zygotes was similar to the control. ET classes significantly affected the clinical outcomes (p < 0.001). Class I ET gave rise to similar rates of clinical outcomes between five groups, but Class II and Class III ET retarded the rates of pregnancy, implantation and live birth and this particularly occurred in Group C, D and E. The rate of early miscarriage was not comparably different between groups. Overall rates in all groups were 41.26% clinical pregnancy, 25.74% implantation and 36.32% live birth, which gave live birth to 252 girls and 252 boys.

CONCLUSIONS

The reduction of motile spermatozoa in severe oligozoospermia decreased the rates of fertilization and good-quality embryo. Obtaining and transfer of good-quality embryos was the good prognostic to achieve prospective clinical outcomes regardless of the severity of oligozoospermia.