Immunofluorescence distribution of actin-associated proteins in human seminiferous tubules of adolescent testes, normal and pathologic

A novel mutation in NEB causing foetal nemaline myopathy with arthrogryposis during early gestation

Nemaline myopathies are a clinically and genetically heterogeneous group of congenital myopathies, mainly characterized by muscle weakness, hypotonia and respiratory insufficiency. Here, we report a male foetus of consanguineous parents with a severe congenital syndrome characterized by arthrogryposis detected at 13 weeks of gestation. We describe severe complex dysmorphic facial and musculoskeletal features by post mortem fetal examination confirming the prenatal diagnosis. Histomorphological and ultrastructural studies of skeletal muscle reveal mini-rods in myotubes caused by a novel homozygous splice-site mutation in NEB (NM_001164508, chr2:g.152,417,623C>A GRCh37.p11 | c.19,102-1G>T ENST00000397345.3). No rods were seen in the myocardium. We discuss the relevance of this mutation in the context of nemaline myopathies associated with early developmental musculoskeletal disorders.

Reactive oxygen, nitrogen, and sulfur species in human male fertility. A crossroad of cellular signaling and pathology

Infertility is a significant global health problem that currently affects one of six couples in reproductive age. The quality of male reproductive cells dramatically decreased over the last years and almost every aspect of modern life additionally worsen sperm functional parameters that consequently markedly increase male infertility. This clearly points out the importance of finding a new approach to treat male infertility. Redox signaling mediated by reactive oxygen, nitrogen and sulfur species (ROS, RNS, and RSS respectively), has appeared important for sperm reproductive function. Present review summarizes the current knowledge of ROS, RNS, and RSS in male reproductive biology and identifies potential targets for development of novel pharmacological and therapeutic approaches for male infertility by targeted therapeutic modulation of redox signaling.

Free radicals in adolescent varicocele testis

We examine the relationship between the structure and function of the testis and the oxidative and nitrosative stress, determined by an excessive production of free radicals and/or decreased availability of antioxidant defenses, which occur in the testis of adolescents affected by varicocele. Moreover, the effects of surgical treatment on oxidative stress were provided. We conducted a PubMed and Medline search between 1980 and 2014 using “adolescent,” “varicocele,” “free radicals,” “oxidative and nitrosative stress,” “testis,” and “seminiferous tubules” as keywords. Cross-references were checked in each of the studies, and relevant articles were retrieved. We conclude that increased concentration of free radicals, generated by conditions of hypoxia, hyperthermia, and hormonal dysfunction observed in adolescent affected by varicocele, can harm germ cells directly or indirectly by influencing nonspermatogenic cells and basal lamina. With regard to few available data in current literature, further clinical trials on the pre- and postoperative ROS and RNS levels together with morphological studies of the cellular component of the testis are fundamental for complete comprehension of the role played by free radicals in the pathogenesis of adolescent varicocele and could justify its pharmacological treatment with antioxidants.

Morphological and surgical overview of adolescent testis affected by varicocele

Varicocele is a common pathology of the testis frequently associated with infertility. For its management, a fine morphological study of the testis, both macroscopically and microscopically, and an accurate choice of surgical procedure are mandatory. The present review focuses its attention on the anatomic substrates of adolescent varicocele and its pathophysiologic modifications. The comprehensive assessment of all the reported alterations should be considered by the clinician before deciding the type of treatment and the timing.

Varicocele and infertility: why a prevention?

The varicocele is the abnormal dilation of the veins of the pampiniform plexus, resulting from an altered venous drainage, and it is considered one of the main causes of male infertility. In this paper we review the most recent observations on the histological, endocrinological, biochemical and clinical alterations reported in adolescents with left idiopathic varicocele. Data indicate that varicocele progressively impairs the reproductive function of the testis. Treatment could improve a number of such damages.

Anchoring junctions as drug targets: role in contraceptive development

In multicellular organisms, cell-cell interactions are mediated in part by cell junctions, which underlie tissue architecture. Throughout spermatogenesis, for instance, preleptotene leptotene spermatocytes residing in the basal compartment of the seminiferous epithelium must traverse the blood-testis barrier to enter the adluminal compartment for continued development. At the same time, germ cells must also remain attached to Sertoli cells, and numerous studies have reported extensive restructuring at the Sertoli-Sertoli and Sertoli-germ cell interface during germ cell movement across the seminiferous epithelium. Furthermore, the proteins and signaling cascades that regulate adhesion between testicular cells have been largely delineated. These findings have unveiled a number of potential "druggable" targets that can be used to induce premature release of germ cells from the seminiferous epithelium, resulting in transient infertility. Herein, we discuss a novel approach with the aim of developing a nonhormonal male contraceptive for future human use, one that involves perturbing adhesion between Sertoli and germ cells in the testis.

Junction restructuring and spermatogenesis: the biology, regulation, and implication in male contraceptive development

Spermatogenesis that occurs in the seminiferous epithelium of adult mammalian testes is associated with extensive junction restructuring at the Sertoli-Sertoli cell, Sertoli-germ cell, and Sertoli-basement membrane interface. While this morphological phenomenon is known and has been described in great details for decades, the biochemical and molecular changes as well as the mechanisms/signaling pathways that define changes at the cell-cell and cell-matrix interface remain largely unknown until recently. In this chapter, we summarize and discuss findings in the field regarding the coordinated efforts of the anchoring [e.g., adherens junction (AJ), such as basal ectoplasmic specialization (basal ES)] and tight junctions (TJs) that are present in the same microenvironment, such as at the blood-testis barrier (BTB), or at distinctly opposite ends of the Sertoli cell epithelium, such as between apical ectoplasmic specialization (apical ES) in the apical compartment, and the BTB adjacent to the basal compartment of the epithelium. These efforts, in turn, regulate and coordinate different cellular events that occur during the seminiferous epithelial cycle. For instance, the events of spermiation and of preleptotene spermatocyte migration across the BTB both take place concurrently at stage VIII of the epithelial cycle of spermatogenesis. Recent findings suggest that these events are coordinated by protein complexes found at the apical and basal ES and TJ, which are located at different ends of the Sertoli cell epithelium. Besides, we highlight important areas of research that can now be undertaken, and functional studies that can be designed to tackle different issues pertinent to junction restructuring during spermatogenesis.

Sertoli-Sertoli and Sertoli-germ cell interactions and their significance in germ cell movement in the seminiferous epithelium during spermatogenesis

Spermatogenesis is the process by which a single spermatogonium develops into 256 spermatozoa, one of which will fertilize the ovum. Since the 1950s when the stages of the epithelial cycle were first described, reproductive biologists have been in pursuit of one question: How can a spermatogonium traverse the epithelium, while at the same time differentiating into elongate spermatids that remain attached to the Sertoli cell throughout their development? Although it was generally agreed upon that junction restructuring was involved, at that time the types of junctions present in the testis were not even discerned. Today, it is known that tight, anchoring, and gap junctions are found in the testis. The testis also has two unique anchoring junction types, the ectoplasmic specialization and tubulobulbar complex. However, attention has recently shifted on identifying the regulatory molecules that "open" and "close" junctions, because this information will be useful in elucidating the mechanism of germ cell movement. For instance, cytokines have been shown to induce Sertoli cell tight junction disassembly by shutting down the production of tight junction proteins. Other factors such as proteases, protease inhibitors, GTPases, kinases, and phosphatases also come into play. In this review, we focus on this cellular phenomenon, recapping recent developments in the field.

Extracellular matrix: recent advances on its role in junction dynamics in the seminiferous epithelium during spermatogenesis

Spermatogenesis takes place in the seminiferous epithelium of the mammalian testis in which one type A1 spermatogonium (diploid, 2n) gives rise to 256 spermatids (haploid, 1n). To accomplish this, developing germ cells, such as preleptotene and leptotene spermatocytes, residing in the basal compartment of the seminiferous epithelium must traverse the blood-testis barrier (BTB) entering into the adluminal compartment for further development into round, elongating, and elongate spermatids. Recent studies have shown that the basement membrane in the testis (a modified form of extracellular matrix, ECM) is important to the event of germ cell movement across the BTB because proteins in the ECM were shown to regulate BTB dynamics via the interactions between collagens, proteases, and protease inhibitors, possibly under the regulation of cytokines. While these findings are intriguing, they are not entirely unexpected. For one, the basement membrane in the testis is intimately associated with the BTB, which represents the basolateral region of Sertoli cells. Also, Sertoli cell tight junctions (TJs) that constitute the BTB are present side-by-side with cell-cell actin-based adherens junctions (AJ, such as basal ectoplasmic specialization [ES]) and intermediate filament-based desmosome-like junctions. As such, the relative morphological layout between TJs, AJs, and desmosome-like junctions in the seminiferous epithelium is in sharp contrast to other epithelia where TJs are located at the apical portion of an epithelium or endothelium, furthest away from ECM, to be followed by AJs and desmosomes, which in turn constitute the junctional complex. For another, anchoring junctions between a cell epithelium and ECM found in multiple tissues, also known as focal contacts (or focal adhesion complex, FAC, an actin-based cell-matrix anchoring junction type), are the most efficient junction type that permits rapid junction restructuring to accommodate cell movement. It is therefore physiologically plausible, and perhaps essential, that the testis is using some components of the focal contacts to regulate rapid restructuring of AJs between Sertoli and germ cells when germ cells traverse the seminiferous epithelium. Indeed, recent findings have shown that the apical ES, a testis-specific AJ type in the seminiferous epithelium, is equipped with proteins of FAC to regulate its restructuring. In this review, we provide a timely update on this exciting yet rapidly developing field regarding how the homeostasis of basement membrane in the tunica propria regulates BTB dynamics and spermatogenesis in the testis, as well as a critical review on the molecular architecture and the regulation of ES in the seminiferous epithelium.

Varicocele and sport in the adolescent age. Preliminary report on the effects of physical training

The effect of physical training on the natural history of varicocele has received little attention. The aim of the present pilot study was to evaluate the prevalence of idiopathic varicocele in young athletes, in the attempt to find a correlation between the training workload and the clinical grade of varicocele. We evaluated 150 adolescents with an age of 10-16 yr (median age: 13 yr). All these subjects were athletes practicing different sport at agonistic level. One hundred and fifty non-athlete adolescents of matched age (median: 13.5 yr) were used as controls. All underwent physical examination, and if a varicocele was suspected, the diagnosis was confirmed or excluded by echo-color-Doppler examination. The young athletes were stratified into two groups according to the different time spent for training: Group 1-6 h training per week; Group 2-7 to 12 h per week. Statistical analysis was performed. A p<0.05 was considered significant. The physical examination revealed a clinical varicocele on the left side in 20 athletes. A significant positive correlation was observed between the Group 2 and the highest grade of varicocele (r2=0.9918, p=0.0041). In the adolescent group used as control we observed a varicocele in 16 cases. A positive correlation was observed between the number of athletes with varicocele and the highest grade of varicocele (r2=0.96, p=0.02). Sport training does not modify the prevalence of varicocele compared to the general population, but physical activity has to be considered as an aggravating factor in the natural history of varicocele. In countries where sport eligibility is necessary for agonistic sport practice, varicocele should be then considered as a conditioning factor.

Dynamic cross-talk between cells and the extracellular matrix in the testis

In the seminiferous tubule of the mammalian testis, one type A1 spermatogonium (diploid, 2n) divides and differentiates into 256 spermatozoa (haploid, n) during spermatogenesis. To complete spermatogenesis and produce approximately 150 x 10(6) spermatozoa each day in a healthy man, germ cells must migrate progressively across the seminiferous epithelium yet remain attach to the nourishing Sertoli cells. This active cell migration process involves precisely controlled restructuring events at the tight (TJ) and anchoring junctions at the cell-cell interface. While the hormonal events that regulate spermatogenesis by follicle-stimulating hormone and testosterone from the pituitary gland and Leydig cells, respectively, are known, less is known about the mechanism(s) that regulates junction restructuring during germ cell movement in the seminiferous epithelium. The relative position of tight (TJs) and anchoring junctions in the testis is of interest. Sertoli cell TJs that constitute the blood-testis barrier (BTB) are present side by side with anchoring junctions and are adjacent to the basement membrane. This intimate physical association with the TJs, the anchoring junctions and the basement membrane (a modified form of extracellular matrix, ECM) suggests a role for the ECM in the junction dynamics of the testis. Indeed, evidence is accumulating that ECM proteins are crucial to Sertoli cell TJ dynamics. In this review, we discuss the pivotal role of tumor necrosis factor alpha (TNFalpha) on BTB dynamics via its effects on the homeostasis of ECM proteins. In addition, discussion will also be focused on the novel findings regarding the role of non-basement-membrane-associated ECM proteins and components of focal adhesion (a cell-matrix anchoring junction type) in the regulation of junction dynamics in the testis.