Testicular gene expression in cryptorchid boys at risk of azoospermia

Construction and analysis of a joint diagnostic model of machine learning for cryptorchidism based on single-cell sequencing

BACKGROUND

Cryptorchidism is a condition in which one or both of a baby's testicles do not fully descend into the bottom of the scrotum. Newborns with cryptorchidism are at increased risk of developing infertility later in life. The aim of this study was to develop a novel diagnostic model for cryptorchidism and to identify new biomarkers associated with cryptorchidism.

METHODS

The study data were obtained from RNA sequencing data of cryptorchid patients from Nantong University Hospital and the Gene Expression Omnibus (GEO) database. Differential expression analysis was used to obtain differentially expressed genes (DEGs) between the control and cryptorchid groups. These DEGs were analyzed for their functions by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment using GSEA software. Random Forest algorithm was used to screen central genes based on these DEGs. Neuralnet software package was used to develop artificial neural network models. Based on clinical data, receiver operating characteristic (ROC) was used to validate the models. Single-cell sequencing analysis was used for the pathogenesis of cryptorchidism.

RESULTS

We obtained a total of 525 important DEGs related to cryptorchidism, which are mainly associated with biological functions such as supramolecular complexes and microtubule cytoskeleton. Random forest approach screening obtained eight hub genes. A neural network based on the hub genes showed a 100% success rate of the model. Finally, single-cell sequencing analysis validated the hub genes.

CONCLUSION

We developed a novel diagnostic model for cryptorchidism using artificial neural networks and validated its utility as an effective diagnostic tool.

Undescended testis: A roundtable discussion based on clinical scenarios - Part 1

Undescended testis (UDT, cryptorchidism) is the most common congenital anomaly of the genital tract. Despite its high incidence, the management of UDT varies between specialties (urology, pediatric surgery, pediatric urology, pediatric endocrinology). Therefore, as the European Association of Urology - Young Academic Urologists Pediatric Urology Working Group, we requested experts around the world to express their own personal approaches against various case scenarios of UDT in order to explore their individual reasoning. We intended to broaden the perspectives of our colleagues who deal with the treatment of this frequent genital malformation.

Loss of WNT4 in the gubernaculum causes unilateral cryptorchidism and fertility defects

Undescended testis (UDT) affects 6% of male births. Despite surgical correction, some men with unilateral UDT may experience infertility with the contralateral descended testis (CDT) showing no A-dark spermatogonia. To improve our understanding of the etiology of infertility in UDT, we generated a novel murine model of left unilateral UDT. Gubernaculum-specific Wnt4 knockout (KO) mice (Wnt4-cKO) were generated using retinoic acid receptor β2-cre mice and were found to have a smaller left-unilateral UDT. Wnt4-cKO mice with abdominal UDT had an increase in serum follicle-stimulating hormone and luteinizing hormone and an absence of germ cells in the undescended testicle. Wnt4-cKO mice with inguinal UDT had normal hormonal profiles, and 50% of these mice had no sperm in the left epididymis. Wnt4-cKO mice had fertility defects and produced 52% fewer litters and 78% fewer pups than control mice. Wnt4-cKO testes demonstrated increased expression of estrogen receptor α and SOX9, upregulation of female gonadal genes, and a decrease in male gonadal genes in both CDT and UDT. Several WNT4 variants were identified in boys with UDT. The presence of UDT and fertility defects in Wnt4-cKO mice highlights the crucial role of WNT4 in testicular development.

A Comparative Cross-Platform Analysis to Identify Potential Biomarker Genes for Evaluation of Teratozoospermia and Azoospermia

Male infertility is a global public health concern. Teratozoospermia is a qualitative anomaly of spermatozoa morphology, contributing significantly to male infertility, whereas azoospermia is the complete absence of spermatozoa in the ejaculate. Thus, there is a serious need for unveiling the common origin and/or connection between both of these diseases, if any. This study aims to identify common potential biomarker genes of these two diseases via an in silico approach using a meta-analysis of microarray data. In this study, a differential expression analysis of genes was performed on four publicly available RNA microarray datasets, two each from teratozoospermia (GSE6872 and GSE6967) and azoospermia (GSE145467 and GSE25518). From the analysis, 118 DEGs were found to be common to teratozoospermia and azoospermia, and, interestingly, sperm autoantigenic protein 17 (SPA17) was found to possess the highest fold change value among all the DEGs (9.471), while coiled-coil domain-containing 90B (CCDC90B) and coiled-coil domain-containing 91 (CCDC91) genes were found to be common among three of analyses, i.e., Network Analyst, ExAtlas, and GEO2R. This observation indicates that SPA17, CCDC90B, and CCDC91 genes might have significant roles to play as potential biomarkers for teratozoospermia and azoospermia. Thus, our study opens a new window of research in this area and can provide an important theoretical basis for the diagnosis and treatment of both these diseases.

A novel role for CFTR interaction with LH and FGF in azoospermia and epididymal maldevelopment caused by cryptorchidism

Cryptorchidism occurs frequently in children with cystic fibrosis. Among boys with cryptorchidism and abrogated mini-puberty, the development of the epididymis and the vas deferens is frequently impaired. This finding suggests that a common cause underlies the abnormal development of Ad spermatogonia and the epididymis. The cystic fibrosis transmembrane conductance regulator (CFTR) is an ATP-binding cassette transporter protein that acts as a chloride channel. The CFTR gene has been associated with spermatogenesis and male fertility. In boys with cryptorchidism, prepubertal hypogonadotropic hypogonadism induces suboptimal expression of the ankyrin-like protein gene, ASZ1, the P-element induced wimpy testis-like gene, PIWIL, and CFTR. The abrogated expression of these gene leads to transposon reactivation, and ultimately, infertility. Curative gonadotropin-releasing hormone agonist (GnRHa) treatment stimulates the expression of CFTR and PIWIL3, which play important roles in the development of Ad spermatogonia and fertility. Furthermore, GnRHa stimulates the expression of the epididymal androgen-sensitive genes, CRISP1, WFDC8, SPINK13, and PAX2, which thereby promotes epididymal development. This review focuses on molecular evidence that favors a role for CFTR in cryptorchidism-induced infertility. Based on information available in the literature, we interpreted our RNA-Seq expression data obtained from samples before and after randomized GnRHa treatment in boys with bilateral cryptorchidism. We propose that, in boys with cryptorchidism, CFTR expression is controlled by luteinizing hormone and testosterone. Moreover, CFTR regulates the activities of genes that are important for fertility and Wolffian duct differentiation.

Temperature is not a major factor in the differentiation of gonocytes into ad spermatogonia and fertility outcome in congenitally cryptorchid boys

Spermatogenesis in mammals is a heat-sensitive developmental pathway incompatible with the typical mammalian body temperature of 37 °C. It is thought that this is the reason why the testicles of most mammalian males are outside of the body cavity, in the scrotum, where they function at approximately 33 °C. It has been suggested that the abnormally high temperature environment of cryptorchid testes may lead to impaired testicular development and adult infertility. Here, I summarize the clinical, genetic, and histological evidence that argues against temperature stress and in favor of hypogonadotropic hypogonadism as the underlying cause of adult infertility in cryptorchidism.

Patient summary: Infertility and an increased risk of testicular cancer in patients diagnosed with undescended testes are the consequence of a hormonal deficiency rather than temperature-induced cellular damage. Cryptorchidism therefore requires both surgical and hormonal treatment.

Fertility of Cryptorchid Testis-An Unsolved Mistery

Cryptorchidism (undescended testis) is one of the most common diagnoses in the pediatric urologist office. Even in the modern era, there still are a lot of debates regarding the optimal time for surgery related to the expected results in relation with the testicular function, including fertility. The review below intends to clarify issues regarding the impact of cryptorchidism on testicular histology and function, semen analysis, the relation between hormonal and surgical treatment, future fertility, and paternity rate.

Adolescent Fertility Preservation: Where Do We Stand Now

Adolescence is a period of flux for many body systems. While fertility potential typically increases after menarche, there are diseases where the opposite occurs and fertility preservation options need to be considered early. In cases of cancer, options vary by pubertal status and can include ovarian tissue cryopreservation, oocyte cryopreservation, sperm cryopreservation, and testicular tissue cryopreservation. Much remains to be learned about fertility and preservation options in those with differences in sexual development (DSDs); however, depending on the form of DSD, fertility preservation may not be necessary. Similarly, traditional fertility counseling in children with galactosemia may need to be changed, as data suggest that fertility rates attributed to other causes of premature ovarian insufficiency may not be as applicable to this disease. Adolescents with Turner's syndrome are at high risk for premature ovarian failure; therefore, it is important to consider options as early as possible since ovarian reserves are depleted quickly. On the other hand, transgender and gender diverse adolescents may even be able to undergo fertility preservation after starting hormone therapy. In all cases, there are additional ethical components including technical/surgical risks in childhood, offering experimental therapies without creating false hope and evaluating children's consent and assent capabilities that must be considered.

Cellular Therapy via Spermatogonial Stem Cells for Treating Impaired Spermatogenesis, Non-Obstructive Azoospermia

Male infertility is a major health problem affecting about 8–12% of couples worldwide. Spermatogenesis starts in the early fetus and completes after puberty, passing through different stages. Male infertility can result from primary or congenital, acquired, or idiopathic causes. The absence of sperm in semen, or azoospermia, results from non-obstructive causes (pretesticular and testicular), and post-testicular obstructive causes. Several medications such as antihypertensive drugs, antidepressants, chemotherapy, and radiotherapy could lead to impaired spermatogenesis and lead to a non-obstructive azoospermia. Spermatogonial stem cells (SSCs) are the basis for spermatogenesis and fertility in men. SSCs are characterized by their capacity to maintain the self-renewal process and differentiation into spermatozoa throughout the male reproductive life and transmit genetic information to the next generation. SSCs originate from gonocytes in the postnatal testis, which originate from long-lived primordial germ cells during embryonic development. The treatment of infertility in males has a poor prognosis. However, SSCs are viewed as a promising alternative for the regeneration of the impaired or damaged spermatogenesis. SSC transplantation is a promising technique for male infertility treatment and restoration of spermatogenesis in the case of degenerative diseases such as cancer, radiotherapy, and chemotherapy. The process involves isolation of SSCs and cryopreservation from a testicular biopsy before starting cancer treatment, followed by intra-testicular stem cell transplantation. In general, treatment for male infertility, even with SSC transplantation, still has several obstacles. The efficiency of cryopreservation, exclusion of malignant cells contamination in cancer patients, and socio-cultural attitudes remain major challenges to the wider application of SSCs as alternatives. Furthermore, there are limitations in experience and knowledge regarding cryopreservation of SSCs. However, the level of infrastructure or availability of regulatory approval to process and preserve testicular tissue makes them tangible and accurate therapy options for male infertility caused by non-obstructive azoospermia, though in their infancy, at least to date.

AKT3 and related molecules as potential biomarkers responsible for cryptorchidism and cryptorchidism-induced azoospermia

BACKGROUND

Cryptorchidism is a common congenital malformation strongly related to future oligospermia and male infertility. Normally functioning early-stage spermatogonia are vital to ensure fertility. The present study aimed to identify new differentially expressed genes (DEGs) associated with signaling pathways related to spermatogonial stem cell (SSC) maintenance during early spermatogenesis.

METHODS

GEO2R was used to screen for genes differentially regulated in cryptorchidism using mRNA expression profiling data in the GEO database. DAVID was used to perform GO and KEGG enrichment analysis of DEGs to analyze their functions. A protein-protein interaction (PPI) network of DEGs was constructed using the STRING database. The hub genes in the PPI networks were identified using Maximal Clique Centrality (MCC) in Cytohubba, and the top 50 genes were displayed as hub genes using Cytoscape software. Then, the miRNAs targeting hub genes were predicted using miRWalk and an mRNA-miRNA interaction network was constructed using Cytoscape. We took the intersection of these target miRNAs and the differentially expressed miRNAs identified from a non-coding RNA sequencing dataset, GSE149084. Furthermore, the intersected miRNAs and their predicted target genes were validated in the testicular tissue of rats with cryptorchidism.

RESULTS

A total of 474 DEGs were identified, most of which were annotated to the PI3K-AKT-mTOR signaling pathway. Hub genes related to the pathway were predicted to be targeted by 27 miRNAs. Further miRNA mining revealed that miRNA-7-5p and miRNA-519d-3p were both dysregulated in cryptorchidism patients. Further, we found that these two miRNAs were predicted with high confidence to share a common target gene, AKT3. In the testicular tissue of rats with cryptorchidism, miRNA-519d-3p was upregulated while miRNA-7-5p and AKT3 were downregulated. We also found that AKT3 plays an essential role in regulating SSC state through the PI3K-AKT-mTOR signaling pathway and that AKT3 is one of the key genes related to SSC self-renewal, proliferation, and differentiation.

CONCLUSIONS

The PI3K-AKT-mTOR signaling pathway functions in SSC maintenance, and alterations in this pathway may explain defects in spermatogenesis. AKT3-related miRNAs, including hsa-miR-7-5p and hsa-miR-519d-3p, might be responsible for cryptorchidism and cryptorchidism-induced azoospermia and serve as potential biomarkers.

E2F1 regulates testicular descent and controls spermatogenesis by influencing WNT4 signaling

Cryptorchidism is the most common urologic birth defect in men and is a predisposing factor of male infertility and testicular cancer, yet the etiology remains largely unknown. E2F1 microdeletions and microduplications contribute to cryptorchidism, infertility and testicular tumors. Although E2f1 deletion or overexpression in mice causes spermatogenic failure, the mechanism by which E2f1 influences testicular function is unknown. This investigation revealed that E2f1-null mice develop cryptorchidism with severe gubernacular defects and progressive loss of germ cells resulting in infertility and, in rare cases, testicular tumors. It was hypothesized that germ cell depletion resulted from an increase in WNT4 levels. To test this hypothesis, the phenotype of a double-null mouse model lacking both Wnt4 and E2f1 in germ cells was analyzed. Double-null mice are fertile. This finding indicates that germ cell maintenance is dependent on E2f1 repression of Wnt4, supporting a role for Wnt4 in germ cell survival. In the future, modulation of WNT4 expression in men with cryptorchidism and spermatogenic failure due to E2F1 copy number variations may provide a novel approach to improve their spermatogenesis and perhaps their fertility potential after orchidopexy.

Male Infertility Knowledgebase: decoding the genetic and disease landscape

Male infertility is a multifactorial condition that contributes to around one-third of cases of infertility worldwide. Several chromosomal aberrations, single-gene and polygenic associations with male factor defects have been reported. These defects manifest as sperm number or sperm quality defects leading to infertility. However, in almost 40% of cases, the genetic etiology of male infertility remains unexplained. Understanding the causal genetic factors is crucial for effective patient management and counseling. Integrating the vast amount of available omics data on male infertility is a first step towards understanding, delineating and prioritizing genes associated with the different male reproductive disorders. The Male Infertility Knowledgebase (MIK) is a manually curated repository developed to boost research on the elusive genetic etiology of male infertility. It integrates information on ∼17 000 genes, their associated pathways, gene ontology, diseases and gene and sequence-based analysis tools. In addition, it also incorporates information on reported chromosomal aberrations and syndromic associations with male infertility. Disease enrichment of genes in MIK indicate a shared genetic etiology between cancer, male and female infertility disorders. While the genes involved in cancer pathways were found to be common causal factors for sperm number and sperm quality defects, the interleukin pathways were found to be shared and enriched between male factor defects and non-reproductive conditions like cardiovascular diseases, metabolic diseases, etc. Disease information in MIK can be explored further to identify high-risk conditions associated with male infertility and delineate shared genetic etiology. Utility of the knowledgebase in predicting novel genes is illustrated by identification of 149 novel candidates for cryptorchidism using gene prioritization and network analysis. MIK will serve as a platform for review of genetic information on male infertility, identification pleiotropic genes, prediction of novel candidate genes for the different male infertility diseases and for portending future high-risk diseases associated with male infertility.

Database URL: http://mik.bicnirrh.res.in/

Age-related presence of spermatogonia in patients with Klinefelter syndrome: a systematic review and meta-analysis

BACKGROUND

Klinefelter syndrome (KS) has been defined by sex chromosome aneuploidies (classically 47, XXY) in the male patient. The peripubertal timeframe in KS patients has been associated with the initiation of progressive testicular fibrosis, loss of spermatogonial stem cells (SSC), hypogonadism and impaired fertility. Less than half of KS patients are positive for spermatozoa in the ejaculate or testis via semen analysis or testicular sperm extraction, respectively. However, the chance of finding spermatogonia including a sub-population of SSCs in KS testes has not been well defined. Given the recent demonstration of successful cell culture for mouse and human SSCs, it could be feasible to isolate and propagate SSCs and transplant the cells back to the patient or to differentiate them in vitro to haploid cells.

OBJECTIVE AND RATIONALE

The main objective of this study was to meta-analyse the currently available data from KS patients to identify the prevalence of KS patients with spermatogonia on testicular biopsy across four age groups (year): fetal/infantile (age ≤ 1), prepubertal (age 1 ≤ x ≤ 10), peripubertal/adolescent (age 10 < x < 18) and adult (age ≥ 18) ages. Additionally, the association of endocrine parameters with presence or absence of spermatogonia was tested to obtain a more powered analysis of whether FSH, LH, testosterone and inhibin B can serve as predictive markers for successful spermatogonia retrieval.

SEARCH METHODS

A thorough Medline/PubMed search was conducted using the following search terms: 'Klinefelter, germ cells, spermatogenesis and spermatogonia', yielding results from 1 October 1965 to 3 February 2019. Relevant articles were added from the bibliographies of selected articles. Exclusion criteria included non-English language, abstracts only, non-human data and review papers.

OUTCOMES

A total of 751 papers were identified with independent review returning 36 papers with relevant information for meta-analysis on 386 patients. For the most part, articles were case reports, case-controlled series and cohort studies (level IV-VI evidence). Spermatogonial cells were present in all of the fetal/infantile and 83% of the prepubertal patients' testes, and in 42.7% and 48.5% of the peripubertal and adult groups, respectively were positive for spermatogonia. Additionally, 26 of the 56 (46.4%) peripubertal/adolescent and 37 of the 152 (24.3%) adult patients negative for spermatozoa were positive for spermatogonia (P < 0.05). In peripubertal/adolescent patients, the mean ± SEM level for FSH was 12.88 ± 3.13 IU/L for spermatogonia positive patients and 30.42 ± 4.05 IU/L for spermatogonia negative patients (P = 0.001); the mean ± SEM level LH levels were 4.36 ± 1.31 and 11.43 ± 1.68 IU/L for spermatogonia positive and negative, respectively (P < 0.01); the mean ± SEM level for testosterone levels were 5.04 ± 1.37 and 9.05 ± 0.94 nmol/L (equal to 145 ± 40 and 261 ± 27 and ng/dl) for the spermatogonia positive and negative groups, respectively (P < 0.05), while the difference in means for inhibin B was not statistically significant (P > 0.05). A similar analysis in the adult group showed the FSH levels in spermatogonia positive and negative patients to be 25.77 ± 2.78 and 36.12 ± 2.90 IU/L, respectively (mean ± SEM level, P < 0.05). All other hormone measurements were not statistically significantly different between groups.

WIDER IMPLICATIONS

While azoospermia is a common finding in the KS patient population, many patients are positive for spermatogonia. Recent advances in SSC in vitro propagation, transplantation and differentiation open new avenues for these patients for fertility preservation. This would offer a new subset of KS patients a chance of biological paternity. Data surrounding the hormonal profiles of KS patients and their relation to fertility should be interpreted with caution as a paucity of adequately powered data exists. Future work is needed to clarify the utility of FSH, LH, testosterone and inhibin B as biomarkers for successful retrieval of spermatogonia.

The Neonatal and Adult Human Testis Defined at the Single-Cell Level

Spermatogenesis has been intensely studied in rodents but remains poorly understood in humans. Here, we used single-cell RNA sequencing to analyze human testes. Clustering analysis of neonatal testes reveals several cell subsets, including cell populations with characteristics of primordial germ cells (PGCs) and spermatogonial stem cells (SSCs). In adult testes, we identify four undifferentiated spermatogonia (SPG) clusters, each of which expresses specific marker genes. We identify protein markers for the most primitive SPG state, allowing us to purify this likely SSC-enriched cell subset. We map the timeline of male germ cell development from PGCs through fetal germ cells to differentiating adult SPG stages. We also define somatic cell subsets in both neonatal and adult testes and trace their developmental trajectories. Our data provide a blueprint of the developing human male germline and supporting somatic cells. The PGC-like and SSC markers are candidates to be used for SSC therapy to treat infertility.

Sohni et al. use scRNA-seq analysis to define cell subsets in the human testis. Highlights include the identification of primordial germ cell- and spermatogonial stem cell-like cell subsets in neonatal testes, numerous undifferentiated spermatogonial cell states in adult testes, and somatic cell subsets in both neonatal and adult testes.

Bioinformatic identification of key genes and molecular pathways in the spermatogenic process of cryptorchidism

This study aims to determine key genes and pathways that could play important roles in the spermatogenic process of patients with cryptorchidism. The gene expression profile data of GSE25518 was obtained from the Gene Expression Omnibus (GEO) database. Microarray data were analyzed using BRB-Array Tools to identify differentially expressed genes (DEGs) between high azoospermia risk (HAZR) patients and controls. In addition, other analytical methods were deployed, including hierarchical clustering analysis, class comparison between patients with HAZR and the normal control group, gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and the construction of a protein–protein interaction (PPI) network. In total, 1015 upregulated genes and 1650 downregulated genes were identified. GO and KEGG analysis revealed enrichment in terms of changes in the endoplasmic reticulum cellular component and the endoplasmic reticulum protein synthetic process in the HAZR group. Furthermore, the arachidonic acid pathway and mTOR pathway were also identified as important pathways, while RICTOR and GPX8 were indentified as key genes involved in the spermatogenic process of patients with cryptorchidism. In present study, we found that changes in the synthesis of endoplasmic reticulum proteins, arachidonic acid and the mTOR pathway are important in the incidence and spermatogenic process of cryptorchidism. GPX8 and RICTOR were also identified as key genes associated with cryptorchidism. Collectively, these data may provide novel clues with which to explore the precise etiology and mechanism underlying cryptorchidism and cryptorchidism-induced human infertility.

Fertility after the Operation of Cryptorchism in Childhood

Cryptorchism is a congenital anomaly of male genitalia, and is defined as a disorder of lowering testicles into the scrotum. In our study, the quality of sperm and fertility of men who were operated from unilateral or bilateral cryptorchism in childhood were analyzed. According to the age in which they were operated, patients were classified into different time groups, subjected to clinical examination and sperm analysis. A normal sperm count was found: 36.9% of the total number of patients operated from unilateral to bilateral cryptorchism. The highest percentage of normal sperm counts was 73.97%: the data which was found in the group that was operated from one-sided cryptorchism to the end of the second year of life. Regardless of the age of the cryptorchism operation, it is possible to expect a disorder of spermatogenesis.

Establishing reproductive potential and advances in fertility preservation techniques for XY individuals with differences in sex development

BACKGROUND

Discordance between gonadal type and gender identity has often led to an assumption of infertility in patients with differences in sex development (DSD). However, there is now greater recognition of fertility being an important issue for this group of patients. Currently, gonadal tissue that may have fertility potential is not being stored for individuals with DSD and, where gonadectomy forms part of management, is often discarded. The area of fertility preservation has been predominantly driven by oncofertility which is a field dedicated to preserving the fertility of patients undergoing gonadotoxic cancer treatment. The use of fertility preservation techniques could be expanded to include individuals with DSD where functioning gonads are present.

METHODS

This is a systematic literature review evaluating original research articles and relevant reviews between 1974 and 2018 addressing DSD and fertility, in vitro maturation of sperm, and histological/ultrastructural assessment of gonadal tissue in complete and partial androgen insensitivity syndrome, 17β-hydroxysteroid dehydrogenase type 3 and 5α-reductase deficiency.

CONCLUSION

Successful clinical outcomes of ovarian tissue cryopreservation are paving the way for similar research being conducted using testicular tissue and sperm. There have been promising results from both animal and human studies leading to cryopreservation of testicular tissue now being offered to boys prior to cancer treatment. Although data are limited, there is evidence to suggest the presence of reproductive potential in the gonads of some individuals with DSD. Larger, more detailed studies are required, but if these continue to be encouraging, individuals with DSD should be given the same information, opportunities and access to fertility preservation as other patient groups.

Plasma concentration of MMP-1 and MMP-2 in boys with cryptorchidism and its lack of correlation with INSL3 and inhibin B

The matrix metalloproteinases are enzymes capable of remodeling of extracellular matrix, and modulate the behavior of cells. Maturation of gubernaculum and spermatogenesis demand proper equilibrium of metalloproteinases and their inhibitors. The aim of this survey was to investigate the levels of matrix metalloproteinase type 1 (MMP-1) and matrix metalloproteinase type 2 (MMP-2) in the plasma of children with unilateral cryptorchidism along with levels of Insulin-like Peptide 3 (INSL3) and inhibin B. INSL3 have a role in gubernaculum development. Inhibin B is produced by Sertoli cells, and its levels reflect the status of the testis germinative epithelium. Fifty boys with an undescended testicle, aged 1-4 years (median = 2.4 years) were enrolled into the study. Fifty boys with inguinal hernia aged 1-4 years, served as controls (median age = 2.1 years). Investigators assessed the MMP-1 and MMP-2 concentrations using Surface Plasmon Resonance Imaging. The levels of INSL-3 and inhibin B were assessed using commercial enzyme-linked immunosorbent assay ELISA. The median concentration of MMP-1 and MMP-2 in the blood plasma of patients with unilateral cryptorchidism, was nearly 2-folds higher than in controls. The great area under the ROC curve with the cut off value of 0.865 for MMP-1, and 0.819 for MMP-2, indicates the high clinical sensitivity and specificity of the test of plasma levels of MMP-1 and MMP-2 for boys with cryptorchidism. The increased plasma levels of MMP-1 and MMP-2, probably reflect the level of apoptosis of the germ cells in undescended testicles, in response to the heat stress during the period of prepubertal testis development. In the group of cryptorchid boys, we found slightly lower concentrations of INSL3, without statistical significance and without correlation with MMP-1 and MMP-2 levels. There were no significant differences in the levels of inhibin B in the group of boys with cryptorchidism and boys with inguinal hernia and it also did not correlate with MMP-1 and MMP-2 concentrations.

Immunolocalization of DMRTB1 in human testis with normal and impaired spermatogenesis

BACKGROUND

The transcription factor DMRTB1 plays a pivotal role in coordinating the transition between mitosis and meiosis in murine germ cells. No reliable data are available for human testis.

OBJECTIVES

The present study aims to examine the testicular expression pattern of DMRTB1 in men showing normal and impaired spermatogenesis.

MATERIALS AND METHODS

Immunohistochemistry was performed using 54 human testicular biopsy specimens and a commercial rabbit polyclonal anti-DMRTB1 primary antibody. RT-PCR complemented immunohistochemistry. To further characterize immunopositive cells and possible co-localization, the proliferation marker Ki-67, the tumor marker PLAP, and an anti-DMRT1 antibody were used.

RESULTS

In men with normal spermatogenesis, a strong immunoreactivity was detectable in a subset of spermatogonia (38.34 ± 2.14%). Some spermatocytes showed a weak immunostaining. Adjacent Sertoli cells were immunonegative. Compared with a hematoxylin and eosin overview staining, these immunopositive cells were almost exclusively identified as A_pale and B spermatogonia and primary spermatocytes in (pre-)leptotene, zygotene, and pachytene stages. In patients with spermatogenic arrest at spermatogonial level, an altered staining pattern was found. No immunoreactivity was detected in Sertoli cells in Sertoli cell-only syndrome. In germ cell neoplasia in situ (GCNIS) tubules, except for a few (0.4 ± 0.03%), pre-invasive tumor cells were immunonegative. Seminoma cells showed no immunostaining.

DISCUSSION

According to previous findings in mice, it seems reasonable that DMRTB1 is expressed in these normal germ cell populations. Moreover, altered staining pattern in spermatogenic arrest at spermatogonial stage suggests a correlation with mitosis and transformation into B spermatogonia. The absence of DMRTB1 in GCNIS cells and tumor cells might be associated with uncontrolled neoplastic cell proliferation and progression into invasive germ cell tumors. Further research is required to elucidate, for example, the role of DMRTB1 in the malignant transformation of human germ cells.

CONCLUSION

Our data indicate a relevant role for DMRTB1 regarding the entry of spermatogonia into meiosis in men.

Is Hormonal Treatment of Congenital Undescended Testes Justified? A Debate

Abnormal germ cell development in cryptorchidism is not a result of a congenital dysgenesis but is preceded by a hormone imbalance and perturbation in germ cell-specific gene expression during abrogated mini-puberty. Adequate treatment with low doses of GnRHa enables 86% of men to achieve a normal sperm count and, most importantly, prevent development of azoospermia. GnRHa treatment induces a significant transcriptional response, including protein coding genes involved in pituitary development, the hypothalamic-pituitary-gonadal axis, and testosterone synthesis. Furthermore, hormonal treatment to achieve epididymo-testicular descent as a first choice of treatment of cryptorchidism has a long tradition in Europe. It eliminates the necessity of subsequent surgery. Moreover, in the cases of non-responders it facilitates orchidopexy and contributes considerably to a reduced incidence of unilateral and the more serious bilateral complete post-surgical testicular atrophy.

PRDM Histone Methyltransferase mRNA Levels Increase in Response to Curative Hormone Treatment for Cryptorchidism-Dependent Male Infertility

There is a correlation between cryptorchidism and an increased risk of testicular cancer and infertility. During orchidopexy, testicular biopsies are performed to confirm the presence of type A dark (Ad) spermatogonia, which are a marker for low infertility risk (LIR). The Ad spermatogonia are absent in high infertility risk (HIR) patients, who are treated with a gonadotropin-releasing hormone agonist (GnRHa) to significantly lower the risk of infertility. Despite its prevalence, little is known about the molecular events involved in cryptorchidism. Previously, we compared the transcriptomes of LIR versus HIR patients treated with and without hormones. Here, we interpreted data regarding members of the positive regulatory domain-containing (PRDM) family; some of which encoded histone methyltransferases that are important for reproduction. We found there were lower levels of PRDM1, PRDM6, PRDM9, PRDM13, and PRDM14 mRNA in the testes of HIR patients compared with LIR patients, and that PRDM7, PRDM9, PRDM12, and PRDM16 were significantly induced after GnRHa treatment. Furthermore, we observed PRDM9 protein staining in the cytoplasm of germ cells in the testes from LIR and HIR patients, indicating that the mRNA and protein levels corresponded. This result indicated that the curative hormonal therapy for cryptorchidism involved conserved chromatin modification enzymes.

Cryostorage of immature and mature human testis tissue to preserve spermatogonial stem cells (SSCs): a systematic review of current experiences toward clinical applications

While the survival rate of children with cancer is increasing, preserving fertility for prepubertal boys is still a challenge. Although intracytoplasmic sperm injection (ICSI) using frozen sperms has revolutionized infertility treatment, it is not applicable for the patients who undergo chemotherapy before puberty since spermatogenesis has not begun. Therefore, preserving spermatogonial stem cells (SSCs) as an experimental option can be provided to prepubertal patients at a risk of damage or loss of their SSCs due to cancer treatments and developmental or genetic disorders. Using frozen SSCs in testicular tissue, successful SSC autotransplantation in mouse and nonhuman primates has shown a promising future for SSC-based cell therapy. Cryopreservation of testicular tissue containing SSCs is the first step to translate SSC-based cell therapy into clinical male infertility treatment, and in the investigation into SSCs, it is very important to evaluate their quantity and functionality during this process. This systematic review summarizes the published data on cryopreservation techniques in human testis tissue for potential utilization in future clinical applications.

Anti-Müllerian Hormone and Testicular Function in Prepubertal Boys With Cryptorchidism

INTRODUCTION

The functional capacity of the testes in prepubertal boys with cryptorchidism before treatment has received very little attention. The assessment of testicular function at diagnosis could be helpful in the understanding of the pathophysiology of cryptorchidism and in the evaluation of the effect of treatment. Anti-Müllerian hormone is a well-accepted Sertoli cell biomarker to evaluate testicular function during childhood without the need for stimulation tests.

OBJECTIVE

The aim of the study was to assess testicular function in prepubertal children with cryptorchidism before orchiopexy, by determining serum anti-Müllerian hormone (AMH). We also evaluated serum gonadotropins and testosterone and looked for associations between testicular function and the clinical characteristics of cryptorchidism.

MATERIALS AND METHODS

We performed a retrospective, cross-sectional, analytical study at a tertiary pediatric public hospital. All clinical charts of patients admitted at the outpatient clinic, and recorded in our database with the diagnosis of cryptorchidism, were eligible. The main outcome measure of the study was the serum concentration of AMH. Secondary outcome measures were serum LH, FSH, and testosterone. For comparison, serum hormone levels from a normal population of 179 apparently normal prepubertal boys were used.

RESULTS

Out of 1,557 patients eligible in our database, 186 with bilateral and 124 with unilateral cryptorchidism were selected using a randomization software. Median AMH standard deviation score was below 0 in both the bilaterally and the unilaterally cryptorchid groups, indicating that testicular function was overall decreased in patients with cryptorchidism. Serum AMH was significantly lower in boys with bilateral cryptorchidism as compared with controls and unilaterally cryptorchid patients between 6 months and 1.9 years and between 2 and 8.9 years of age. Serum AMH below the normal range reflected testicular dysfunction in 9.5-36.5% of patients according to the age group in bilaterally cryptorchid boys and 6.3-16.7% in unilaterally cryptorchid boys. FSH was elevated in 8.1% and LH in 9.1% of boys with bilateral cryptorchidism, most of whom were anorchid. In patients with present testes, gonadotropins were only mildly elevated in less than 5% of the cases. Basal testosterone was mildly decreased in patients younger than 6 months old, and uninformative during childhood.

CONCLUSION

Prepubertal boys with cryptorchidism, especially those with bilaterally undescended gonads, have decreased AMH production. Although serum AMH may fall within the normal range, there is a considerable prevalence of testicular dysfunction during childhood in this frequent condition.

On the descent of the epididymo-testicular unit, cryptorchidism, and prevention of infertility

This comprehensive review provides in-depth coverage of progress made in understanding the molecular mechanisms underlying cryptorchidism, a frequent pathology first described in about 1786 by John Hunter. The first part focuses on the physiology, embryology, and histology of epididymo-testicular descent. In the last 20 years epididymo-testicular descent has become the victim of schematic drawings with an unjustified rejection of valid histological data. This part also includes discussion on the roles of gonadotropin-releasing hormone, fibroblast growth factors, Müllerian inhibiting substance, androgens, inhibin B, and insulin-like 3 in epididymo-testicular descent. The second part addresses the etiology and histology of cryptorchidism as well as the importance of mini-puberty for normal fertility development. A critical view is presented on current clinical guidelines that recommend early orchidopexy alone as the best possible treatment. Finally, by combining classical physiological information and the output of cutting-edge genomics data into a complete picture the importance of hormonal treatment in preventing cryptorchidism-induced infertility is underscored.

DMRTC2, PAX7, BRACHYURY/T and TERT Are Implicated in Male Germ Cell Development Following Curative Hormone Treatment for Cryptorchidism-Induced Infertility

Defective mini-puberty results in insufficient testosterone secretion that impairs the differentiation of gonocytes into dark-type (Ad) spermatogonia. The differentiation of gonocytes into Ad spermatogonia can be induced by administration of the gonadotropin-releasing hormone agonist, GnRHa (Buserelin, INN)). Nothing is known about the mechanism that underlies successful GnRHa treatment in the germ cells. Using RNA-sequencing of testicular biopsies, we recently examined RNA profiles of testes with and without GnRHa treatment. Here, we focused on the expression patterns of known gene markers for gonocytes and spermatogonia, and found that DMRTC2, PAX7, BRACHYURY/T, and TERT were associated with defective mini-puberty and were responsive to GnRHa. These results indicate novel testosterone-dependent genes and provide valuable insight into the transcriptional response to both defective mini-puberty and curative GnRHa treatment, which prevents infertility in man with one or both undescended (cryptorchid) testes.

Gene Expression Changes Underlying Idiopathic Central Hypogonadism in Cryptorchidism with Defective Mini-Puberty

The whole genome RNA profiling of testicular biopsies by DNA strand-specific RNA sequencing was examined to determine a potential causative role of isolated congenital cryptorchidism in azoospermia and/or infertility in the context of our previously published GeneChip data. Cryptorchid patients, aged 7 months to 5 years and otherwise healthy, were enrolled in this prospective study. During surgery, testicular tissue biopsies were obtained for histological examination and RNA sequencing. Fifteen patients were selected based on the histological results and were divided into 2 groups. Seven were classified as belonging to the high infertility risk (HIR) and 8 to the low infertility risk (LIR) group. Cryptorchid boys in the HIR group lacked transformation of gonocytes into Ad spermatogonia due to impaired mini-puberty. This group of patients will be infertile despite successful surgery. The new important finding was a decreased PROK2, CHD7, FGFR1, and SPRY4 gene expression in the HIR group. Furthermore, identification of multiple differences in gene expression between HIR and LIR groups underscores the importance of an intact hypothalamic-pituitary-gonadal axis for fertility development. Our RNA profiling data strongly support the theory that in the HIR group of cryptorchid boys insufficient PROK2/CHD7/FGFR1/SPRY4 gene expression induces deficient LH secretion, resulting in impaired mini-puberty and infertility. We therefore recommend hormonal treatment for this cohort of cryptorchid boys with defective mini-puberty following a seemingly successful orchidopexy.

Prospective study of histological and endocrine parameters of gonadal function in boys with cryptorchidism

INTRODUCTION

A transient increase in gonadotropins and testosterone during mini-puberty causes gonocytes to differentiate into Ad spermatogonia, which establish male germ cell memory and male-specific DNA methylation pathways. Over half of patients with unilateral cryptorchidism and the majority of patients with bilateral cryptorchidism display an abnormal spermiogram, which indicates that unilateral cryptorchidism is a bilateral disease; therefore, it represents a serious andrological problem. The aim of this study was to evaluate relationships between hormonal parameters and testicular biopsy findings in boys with cryptorchidism.

METHOD

Seventy-one boys (median age 15 months; range 7-65 months) who underwent orchidopexy (24% had bilateral cryptorchidism) were tested for serum LH, FSH, and inhibin B. With ipsilateral testis biopsy histology, we determined the tubular fertility index (TFI), Ad spermatogonia counts, and Ad/tubular index (Ad/T). We compared age groups (<18 vs. >18 months old); groups with and without Ad spermatogonia; groups with unilateral and bilateral cryptorchidism; and extreme groups with high infertility risk (HIR; n = 12; TFI <0.2; Ad/T = 0) and low infertility risk (LIR; n = 9; TFI >0.9; Ad/T>0.02).

RESULTS

Of the specimens, 38% had no Ad spermatogonia. Age was significantly negatively correlated with TFI and Ad/T, but positively correlated with FSH. Median LH values were significantly higher in LIR than in HIR groups. Unilateral and bilateral cryptorchidism showed similar TFI, Ad/T, and hormone concentrations. The areas under ROC curves for FSH, LH, and inhibin B (0.66, 0.601, and 0.599, respectively) showed low diagnostic value for predicting HIR (no Ad spermatogonia).

CONCLUSION

Our observation of lower plasma LH levels in the group with the most pronounced testicular pathology was the opposite of what we would have expected if testicular pathological changes were caused by a primary gonadal defect. Therefore, low plasma LH levels in the HIR group confirmed the notion that this group of patients with cryptorchidism had hypogonadotropic hypogonadism. The estimated incidence of defective mini-puberty in boys with cryptorchidism could be as high as 50%. Testicular biopsies from boys with cryptorchidism lacked Ad spermatogonia. Fertility parameters worsened with age. Significantly lower basal LH in the HIR group indicated hypogonadotropic hypogonadism. Serum hormone levels could not predict histological biopsy findings.

Experimental testicular tissue banking to generate spermatogenesis in the future: A multidisciplinary team approach

Spermatogonial stem cell (SSC) loss due to cancer treatment, developmental disorder or genetic abnormality may cause permanent infertility. Cryopreservation of ejaculated sperm is an effective method of fertility preservation in adult males at risk of infertility. However this is not an option in pre-pubertal boys because spermatogenesis has not yet started, and it is difficult in adolescents who are not sexually mature. Therefore testicular tissue cryopreservation to preserve SSCs for future generation of spermatogenesis, either in vivo or in vitro, could be an option for these groups of patients. Although SSC transplantation has been successful in several species including non-human primates, it is still experimental in humans. There are several remaining concerns which need to be addressed before initiating trials of human SSC autotransplantation. Establishment of a testicular tissue banking system is a fundamental step towards using SSC technology as a fertility preservation method. It is important to understand the consultation, harvesting the testicular tissue, histological evaluation, cryopreservation, and long term storage aspects. We describe here a multidisciplinary approach to establish testicular tissue banking for males at risk of infertility.

Exploring the roles of basal transcription factor 3 in eukaryotic growth and development

Basal transcription factor 3 (BTF3) has been reported to play a significant part in the transcriptional regulation linking with eukaryotes growth and development. Alteration in the BTF3 gene expression patterns or variation in their activities adds to the explanation of different signaling pathways and regulatory networks. Moreover, BTF3s often respond to numerous stresses, and subsequently they are involved in regulation of various mechanisms. BTF3 proteins also function through protein-protein contact, which can assist us to identify the multifaceted processes of signaling and transcriptional regulation controlled by BTF3 proteins. In this review, we discuss current advances made in starting to explore the roles of BTF3 transcription factors in eukaryotes especially in plant growth and development.

Piwi-pathway alteration induces LINE-1 transposon derepression and infertility development in cryptorchidism

Spermatogonia contain processing bodies that harbor P-element-induced wimpy testis (Piwi) proteins. Piwi proteins are associated specifically with Piwi-interacting RNAs to silence transposable DNA elements. Loss-of-function mutations in the Piwi pathway lead to derepression of transposable elements, resulting in defective spermatogenesis. Furthermore, deletion of gametocyte-specific factor 1 (GTSF1), a factor involved in Piwi-mediated transcriptional repression, causes male-specific sterility and derepression of LINE-1 (L1) retrotransposons. No previous studies have examined GTSF1, L1 and PIWIL4 expression in cryptorchidism. We examined transposon-silencing genes and L1 transposon expression in testicular biopsies with Affymetrix microarrays and immunohistology. Seven members of the Tudor gene family, 3 members of the DEAD-box RNA helicase family, and the GTSF1 gene were found to show significantly lower RNA signals in the high-infertility-risk group. In the immunohistochemical analysis, patients from the low-infertility-risk group showed coherently stronger staining for GTSF1 and PIWIL4 proteins and weaker staining for L1 transposon when compared to the high-infertility-risk samples. These new findings provide first evidence consistent with the idea that infertility in cryptorchidism is a consequence of alterations in the Piwi pathway and transposon derepression induced by the impaired function of mini-puberty.

Hormonal therapy using gonadotropin releasing hormone for improvement of fertility index among children with cryptorchidism: a meta-analysis and systematic review

BACKGROUND/PURPOSE

Gonadotropin releasing hormone(GnRH) as an adjunct to orchidopexy for the treatment of cryptorchidism is still controversial. Present evidences were studied through a meta-analysis of comparative clinical trials.

METHOD

Systematic literature search was done up to September 30, 2013. Studies were independently appraised by two reviewers. Continuous data of fertility indices were extracted as weighted mean difference (WMD) and standard deviation (SD); while nominal data of fertility indices were extracted as relative risk (RR). Random effects model was used to analyze the pooled effect estimates. Inter-study heterogeneity and publication bias were assessed. PROSPERO Protocol registration (CRD42013004922).

RESULTS

Ten eligible studies were included. The pooled effect estimates showed that cryptorchid children treated with GnRH when compared with controls, have significantly increased germ cell per tubule (WMD: 0.35; 95% CI 0.07-0.62, P=0.01) and increased RR to have normal value of germ cell per tubule (RR: 2.86; 95% CI 1.73-4.71, P<0.0001). Inter-study heterogeneity was noted, source identified with subgroup analysis. Publication bias was not evident. No GnRH related adverse events were reported in all studies.

CONCLUSION

Evidence suggests that a subset of boys with cryptorchidism may benefit from GnRH as adjunctive to orchidopexy in improving the fertility index. However, future studies are recommended to specifically identify subgroup characteristics of cryptorchidism that will clearly benefit from the treatment.

Effects on normalized testicular atrophy index (TAIn) in cryptorchid infants treated with GnRHa pre and post-operative vs surgery alone: a prospective randomized trial and long-term follow-up on 62 cases

PURPOSE

The aim of this study was to investigate the effects of gonadotropin releasing hormone analog (GnRHa) therapy on normalized testicular atrophy index (TAIn) using gonadorelin before and after orchiopexy.

METHODS

62 infants with 87 undescended testes (UDT) were prospectively assigned to two homogeneous groups according to age, position of UDT and TAIn. The patients were randomized to receive either orchiopexy alone or orchiopexy combined with GnRHa as nasal spray at 1.2 mg daily for 4 weeks before surgery and 4 weeks after surgery. Surgical approaches were relative to the position of the UDT: Shoemakers technique in proximal-UDT and Bianchi technique in distal-UDT. All the patients were evaluated clinically and sonographically 1 month before surgery, at the time of surgery, 1 month, 6 months and 5 years after surgery.

RESULTS

Ultrasound data in our study have shown a statistically significant decrease of TAIn in children given additional HT only after 5 years of follow-up, in unilateral cases and in the entirety of treated patients; in bilateral cases this difference was not statistically significant.

CONCLUSION

Patients with a TAIn >20% treated with preoperative and post-operative GnRHa therapy have a significant increase in testicular volume after 5 years of follow-up, as shown by the relative reduction of TAIn values.

Increased gene copy number of VAMP7 disrupts human male urogenital development through altered estrogen action

Vesicle transport is intimately connected with key nuclear functions and transcriptional regulation. Here, children born with congenital genitourinary tract masculinization disorders were analyzed by array-Comparative Genomic Hybridization, which revealed the presence of de novo copy number gains on Xq28 encompassing the VAMP7 gene encoding a vesicle-trafficking protein. Humanized VAMP7 BAC transgenic mice displayed cryptorchidism, urethral defects, and hypospadias. Mutant mice exhibited reduced penile length, focal spermatogenic anomalies, diminished sperm motility, and subfertility. VAMP7 colocalized with estrogen receptor alpha (ESR1) in the presence of ligand. Elevated levels of VAMP7 markedly intensified ESR1 transcriptional activity by increasing ESR1 protein cellular content upon ligand stimulation and up-regulated the expression of estrogen-responsive genes including ATF3, CYR61, and CTGF, all of which are implicated in human hypospadias. Hence, increased gene dosage of the SNARE protein, VAMP7, enhances estrogen receptor action in male genitourinary tissues, affects the virilization of the reproductive tract, and results in genitourinary birth defects in humans.

Generation and characterization of human cryptorchid-specific induced pluripotent stem cells from urine

Cryptorchidism is a common congenital birth defect in human beings with the possible complication of infertility. An in vitro model of cryptorchidism might be valuable due to the inaccessibility of human embryos for research purposes. In this study, we reprogrammed urine cells containing genetic variations in insulin-like factor 3, zinc finger (ZNF) 214, and ZNF215 from a cryptorchid patient by introducing human OCT4, SOX2, C-MYC, and KLF4 with lentivirus. The cells were then replated on irradiated mouse embryonic fibroblasts and cultured with the human embryonic stem (ES) cell medium. The compact colonies with well-defined borders were manually picked, and 2 induced pluripotent cell lines were fully characterized. Our results demonstrated that these 2 cell lines were similar to human ES cells in morphological appearance, marker expression, and epigenetic status of the pluripotent cell-specific gene, OCT4. These cells could be differentiated into cells of all 3 germ layers in teratomas and in vitro, including into the VASA-positive germ cell lineage. Both parental urine cells and the reprogrammed cells possessed the normal karyotype and the same short tandem repeat loci, indicating that these 2 cell population share the same genetic identity. This establishment and characterization of human urine-derived cryptorchid-specific induced pluripotent stem cells could present a good human genetic system for future studies investigating the molecular mechanism of cryptorchidism.

Testicular cancer and cryptorchidism

The failure of testicular descent or cryptorchidism is the most common defect in newborn boys. The descent of the testes during development is controlled by insulin-like 3 peptide and steroid hormones produced in testicular Leydig cells, as well as by various genetic and developmental factors. While in some cases the association with genetic abnormalities and environmental causes has been shown, the etiology of cryptorchidism remains uncertain. Cryptorchidism is an established risk factor for infertility and testicular germ cell tumors (TGCT). Experimental animal models suggest a causative role for an abnormal testicular position on the disruption of spermatogenesis however the link between cryptorchidism and TGCT is less clear. The most common type of TGCT in cryptorchid testes is seminoma, believed to be derived from pluripotent prenatal germ cells. Recent studies have shown that seminoma cells and their precursor carcinoma in situ cells express a number of spermatogonial stem cell (SSC) markers suggesting that TGCTs might originate from adult stem cells. We review here the data on changes in the SSC somatic cell niche observed in cryptorchid testes of mouse models and in human patients. We propose that the misregulation of growth factors' expression may alter the balance between SSC self-renewal and differentiation and shift stem cells toward neoplastic transformation.

Deficient expression of genes involved in the endogenous defense system against transposons in cryptorchid boys with impaired mini-puberty

Mini-puberty is the period between 30 and 80 days after birth when testosterone and gonadotropin surges occur in male infants to induce the transformation of gonocytes into adult/dark spermatogonia. Cryptorchid boys with impaired mini-puberty develop infertility despite timely and successful surgical treatment. The decreased germ cell count found in this group of boys could be the result of uncontrolled transposon activity inducing genomic instability and germ cell death. A genome-wide analysis of 18 cryptorchid and 4 control testes was performed with Affymetrix chips. We found that 5 of 8 genes that are important for transposon silencing were not expressed in the high azoospermia risk group of cryptorchid boys but were expressed in the low azoospermia risk and control groups. Two genes, CBX3 and DNMT1, were equally expressed in all 3 groups. Impaired expression of the DDX4, MAEL,MOV10L1, PIWIL2, PIWIL4, and TDRD9 genes in the group of cryptorchid boys at high risk of infertility indicates that gene instability induced by impaired expression of transposon silencing genes contribute to the development of azoospermia. Intact mini-puberty appears to be essential for the development of the endogenous defense system mediated by transposon silencing.

Evaluation of the azoospermic male

When presented with an azoospermic patient, a thorough history and careful, considered physical examination often leads to a definite or presumptive diagnosis. An algorithmic, logical thought process is important to have in mind when embarking on the evaluation. Adjunctive laboratory tests, such as hormonal assays or genetic studies, are often complementary and/or additive and allow a very precise determination to be made as to the etiologies, either genetic or acquired. It is only with this information that a therapeutic plan can be made for the patient. As will be discussed, a targeted approach to testing is far more satisfying and cost-effective than a blind, shotgun approach.