Maturation phenotype of Sertoli cells in testicular biopsies of azoospermic men

Chronic asymptomatic orchitis in dogs alters Sertoli cell number and maturation status

Infertility due to non-obstructive azoospermia is a common diagnosis in infertile male dogs. Chronic asymptomatic orchitis (CAO) has been postulated as a significant cause of non-obstructive azoospermia in acquired male canine infertility. Despite severe microenvironmental changes, some resilient spermatogonial stem cells persist in CAO-affected testes. As Sertoli cells play an essential role in spermatogenesis and the testicular micromilieu, they represent a new target for CAO potential treatment and consequently deserve further investigation. To investigate Sertoli cell number and maturational status, different markers [Vimentin, anti-Müllerian hormone (AMH), and cytokeratin-18 (CK18)] were evaluated in healthy and CAO-affected testes at mRNA and protein levels. Sertoli cell number was reduced in CAO-affected dogs. Sertoli cells also partly returned to an immature status, as indicated by the expression of AMH and CK18 at mRNA and protein levels. The degree of spermatogenesis disruption matched with the degree of Sertoli cell alterations. The investigation of CAO in this study is limited by the number of samples and the lack of testicular volume measurements, but this does not diminish its importance in new findings. In conclusion, this study identifies alterations in Sertoli cell number and maturation status as a cause or consequence of CAO. The results indicate the need to restore Sertoli cell function as a potential therapeutic target for a successful restart of spermatogenesis.

Complete or partial loss of the Y chromosome in an unselected cohort of 865 non-vasectomized, azoospermic men

BACKGROUND

Structural abnormalities as well as minor variations of the Y chromosome may cause disorders of sex differentiation or, more frequently, azoospermia. This study aimed to determine the prevalence of loss of Y chromosome material within the spectrum ranging from small microdeletions in the azoospermia factor region (AZF) to complete loss of the Y chromosome in azoospermic men.

RESULTS

Eleven of 865 azoospermic men (1.3%) collected from 1997 to 2022 were found to have a karyotype including a 45,X cell line. Two had a pure 45,X karyotype and nine had a 45,X/46,XY mosaic karyotype. The AZF region, or part of it, was deleted in eight of the nine men with a structural abnormal Y-chromosome. Seven men had a karyotype with a structural abnormal Y chromosome in a non-mosaic form. In addition, Y chromosome microdeletions were found in 34 men with a structural normal Y chromosome. No congenital malformations were detected by echocardiography and ultrasonography of the kidneys of the 11 men with a 45,X mosaic or non-mosaic cell line.

CONCLUSIONS

In men with azoospermia, Y chromosome loss ranging from small microdeletions to complete loss of the Y chromosome was found in 6.1% (53/865). Partial AZFb microdeletions may give a milder testicular phenotype compared to complete AZFb microdeletions.

Expression of Intermediate Filaments in the Developing Testis and Testicular Germ Cell Cancer

Cytokeratin and desmin expression have been associated with Sertoli cell maturity and the development of testicular germ cell cancer (TGCC). Thus, the present study aimed to characterize the expression of these intermediate filaments in normal testis development and TGCC. Cytokeratin and desmin were determined by immunohistochemistry and immunofluorescence in human fetal, and adult testis and tissue from patients with pre-invasive germ cell neoplasia in-situ (GCNIS) or invasive TGCC. Desmin was expressed in Sertoli cells of the human fetal testis, and the proportion of desmin expressing Sertoli cells was significantly reduced in the second trimester, compared with the first trimester (31.14% vs. 6.74%, p = 0.0016). Additionally, Desmin was expressed in the majority of Sertoli cells in the adult testis and TGCC samples. Cytokeratin was detected in Sertoli cells of human fetal testis but was not expressed in Sertoli cells of human adult testis. In patients with TGCC, cytokeratin was not expressed in Sertoli cells in tubules with active spermatogenesis but was detected in Sertoli cells in tubules containing GCNIS cells in patients with both pre-invasive and invasive TGCC. In conclusion, desmin was not associated with Sertoli cell maturation or progression to TGCC. However, cytokeratin appeared to be an indicator of impaired Sertoli cell maturation.

The predictive factors of successful sperm retrieval for men with Y chromosome AZFc microdeletion

PURPOSE

To identify key predictors for successful sperm retrieval in men with AZFc microdeletion.

METHODS

Totally, 71 infertile men with confirmed AZFc microdeletion were studied. For each patient, the endocrine profile including serum follicle stimulating hormone (FSH), luteinizing hormone, total testosterone, prolactin, and estradiol was recorded, along with intratesticular testosterone levels (ITT), age, and testicular size. The factors were further analyzed to determine the key predictors for successful sperm retrieval.

RESULTS

Of the 71 men with AZFc microdeletion, 52 (73.2%) were classified as having non-obstructive azoospermia (NOA), 7 (9.9%) as having cryptozoospermia, and 12 (15.8%) as having severe oligoasthenoteratozoospermia. Of the 52 men with azoospermia, 47 received microdissection testicular sperm retrieval, and sperm retrieval was successful in 35 of those cases (74.5%). A significantly lower serum FSH (p = 0.03) was found in those patients from whom sperm could be successfully retrieved. The area under the receiving operating characteristic curve for FSH was determined to be 0.721. Using an FSH cutoff point of 12.95 mIU/mL, the model for predicting successful sperm retrieval was found to have 51.4% sensitivity, 83.3% specificity, 90.0% positive predictive value, and 37.0% negative predictive value. ITT levels were obtained from 7 NOA patients, the mean ITT and the mean ITT/serum testosterone ratio was 1932.8 ng/ml and 567.2 in 6 men with successful sperm retrieval, whereas, in a patient with fail sperm retrieval, the levels were 2370 ng/ml and 393.0.

CONCLUSION

Men exhibiting AZFc microdeletion with discernible spermatogenesis from whom sperm was successfully retrieved by mTESE generally presented with relatively lower FSH levels.

Sertoli and Germ Cells Within Atrophic Seminiferous Tubules of Men With Non-Obstructive Azoospermia

BACKGROUND

Infertile men with non-obstructive azoospermia (NOA) have impaired spermatogenesis. Dilated and un-dilated atrophic seminiferous tubules are often present in the testes of these patients, with the highest likelihood of active spermatogenesis in the dilated tubules. Little is known about the un-dilated tubules, which in NOA patients constitute the majority. To advance therapeutic strategies for men with NOA who fail surgical sperm retrieval we aimed to characterize the spermatogonial stem cell microenvironment in atrophic un-dilated tubules.

METHODS

Testis biopsies approximately 3x3x3 mm³ were obtained from un-dilated areas from 34 patients. They were classified as hypospermatogenesis (HS) (n=5), maturation arrest (MA) (n=14), and Sertoli cell only (SCO) (n= 15). Testis samples from five fertile men were included as controls. Biopsies were used for histological analysis, RT-PCR analysis and immunofluorescence of germ and Sertoli cell markers.

RESULTS

Anti-Müllerian hormone mRNA and protein expression was increased in un-dilated tubules in all three NOA subtypes, compared to the control, showing an immature state of Sertoli cells (p<0.05). The GDNF mRNA expression was significantly increased in MA (P=0.0003). The BMP4 mRNA expression showed a significant increase in HS, MA, and SCO (P=0.02, P=0.0005, P=0.02, respectively). The thickness of the tubule wall was increased 2.2-fold in the SCO-NOA compared to the control (p<0.05). In germ cells, we found the DEAD-box helicase 4 (DDX4) and melanoma-associated antigen A4 (MAGE-A4) mRNA and protein expression reduced in NOA (MAGE-A: 46% decrease in HS, 53% decrease in MA, absent in SCO). In HS-NOA, the number of androgen receptor positive Sertoli cells was reduced 30% with a similar pattern in mRNA expression. The γH2AX expression was increased in SCO as compared to HS and MA. However, none of these differences reached statistical significance probably due to low number of samples.

CONCLUSIONS

Sertoli cells were shown to be immature in un-dilated tubules of three NOA subtypes. The increased DNA damage in Sertoli cells and thicker tubule wall in SCO suggested a different mechanism for the absence of spermatogenesis from SCO to HS and MA. These results expand insight into the differences in un-dilated tubules from the different types of NOA patients.

Effect of Wuzi Yanzong Pills on Sertoli cells and blood-testis barrier in heat-stressed rats based on Akt signalling pathway

The blood-testis barrier (BTB) of Sertoli cells (SCs) is an important biological barrier that maintains spermatogenesis and provides a favourable microenvironment for spermatogenesis. However, heat stress can directly damage the BTB structural proteins of testicular SCs, leading to dyszoospermia. Wuzi Yanzong Pills (WYP) is a traditional Chinese medicine formula used to treat male reproductive diseases. However, whether WYP could ameliorate heat stress injury in primary SCs extracted from rat testes and BTB proteins remains unknown. Here, treatment with WYP (low, medium and high dose) increased the SC viability and the proliferation of cell antigen Ki67 significantly. Additionally, it promoted SC maturation, which presented in the form of increased androgen receptors (ARs) and decreased cytokeratin 18 (CK-18) in three WYP dose groups. WYP upregulated BTB proteins such as zonula occludens 1 (ZO-1) and occludin across all WYP groups and decreased phosphorylated Akt (p-Akt) in the middle and high-dose groups; however, ZO-1 and occludin recovery were reduced with the presence of Akt inhibitor in WYP groups. WYP improved SC viability and proliferation, and ameliorated dedifferentiation and BTB-proteins damaged by heat stress via Akt signalling. The findings present theoretical support for the effects of WYP in the management of dyszoospermia and male infertility.

Common markers of testicular Sertoli cells

INTRODUCTION

Sertoli cells play central roles in the development of testis formation in fetuses and the initiation and maintenance of spermatogenesis in puberty and adulthood, and disorders of Sertoli cell proliferation and/or functional maturation can cause male reproductive disorders at various life stages. It's well documented that various genes are either overexpressed or absent in Sertoli cells during the conversion of an immature, proliferating Sertoli cell to a mature, non-proliferating Sertoli cell, which are considered as Sertoli cell stage-specific markers. Thus, it is paramount to choose an appropriate Sertoli cell marker that will be used not only to identify the developmental, proliferative, and maturation of Sertoli cell status in the testis during the fetal period, prepuberty, puberty, or in the adult, but also to diagnose the mechanisms underlying spermatogenic dysfunction.

AREAS COVERED

In this review, we principally enumerated 5 categories of testicular Sertoli cell markers - including immature Sertoli cell markers, mature Sertoli cell markers, immature/mature Sertoli cell markers, Sertoli cell functional markers, and others.

EXPERT OPINION

By delineating the characteristics and applications of more than 20 Sertoli cell markers, this review provided novel Sertoli cell markers for the more accurate diagnosis and mechanistic evaluation of male reproductive disorders.

Haploid male germ cells-the Grand Central Station of protein transport

BACKGROUND

The precise movement of proteins and vesicles is an essential ability for all eukaryotic cells. Nowhere is this more evident than during the remarkable transformation that occurs in spermiogenesis-the transformation of haploid round spermatids into sperm. These transformations are critically dependent upon both the microtubule and the actin cytoskeleton, and defects in these processes are thought to underpin a significant percentage of human male infertility.

OBJECTIVE AND RATIONALE

This review is aimed at summarising and synthesising the current state of knowledge around protein/vesicle transport during haploid male germ cell development and identifying knowledge gaps and challenges for future research. To achieve this, we summarise the key discoveries related to protein transport using the mouse as a model system. Where relevant, we anchored these insights to knowledge in the field of human spermiogenesis and the causality of human male infertility.

SEARCH METHODS

Relevant studies published in English were identified using PubMed using a range of search terms related to the core focus of the review-protein/vesicle transport, intra-flagellar transport, intra-manchette transport, Golgi, acrosome, manchette, axoneme, outer dense fibres and fibrous sheath. Searches were not restricted to a particular time frame or species although the emphasis within the review is on mammalian spermiogenesis.

OUTCOMES

Spermiogenesis is the final phase of sperm development. It results in the transformation of a round cell into a highly polarised sperm with the capacity for fertility. It is critically dependent on the cytoskeleton and its ability to transport protein complexes and vesicles over long distances and often between distinct cytoplasmic compartments. The development of the acrosome covering the sperm head, the sperm tail within the ciliary lobe, the manchette and its role in sperm head shaping and protein transport into the tail, and the assembly of mitochondria into the mid-piece of sperm, may all be viewed as a series of overlapping and interconnected train tracks. Defects in this redistribution network lead to male infertility characterised by abnormal sperm morphology (teratozoospermia) and/or abnormal sperm motility (asthenozoospermia) and are likely to be causal of, or contribute to, a significant percentage of human male infertility.

WIDER IMPLICATIONS

A greater understanding of the mechanisms of protein transport in spermiogenesis offers the potential to precisely diagnose cases of male infertility and to forecast implications for children conceived using gametes containing these mutations. The manipulation of these processes will offer opportunities for male-based contraceptive development. Further, as increasingly evidenced in the literature, we believe that the continuous and spatiotemporally restrained nature of spermiogenesis provides an outstanding model system to identify, and de-code, cytoskeletal elements and transport mechanisms of relevance to multiple tissues.

Characterization of the stem cell niche components within the seminiferous tubules in testicular biopsies of Klinefelter patients

OBJECTIVE

To characterize the tubular environment in testicular biopsy tissues from patients with Klinefelter syndrome (KS).

DESIGN

Observational immunohistochemical study.

SETTING

Academic research unit.

PATIENT(S)

Males with KS and controls at different developmental time points: fetal, prepubertal, peripubertal, and adult.

INTERVENTION(S)

Immunohistochemical analysis of testicular biopsies samples to characterize maturation of Sertoli cells and tubular wall components-peritubular myoid cells (PTMC) and extracellular matrix (ECM) proteins.

MAIN OUTCOME MEASURE(S)

Intensity of antimüllerian hormone staining; proportion of Sertoli cells expressing androgen receptor (AR); and expression of tubular wall markers as characterized by identifying abnormal staining patterns.

RESULT(S)

Decreased expression for alpha smooth muscle actin 2 (ACTA2) was observed in peripubertal and adult KS as well as in Sertoli cell only (SCO) patients. Altered expression patterns for all ECM proteins were observed in SCO and KS biopsy tissues compared with controls. Only for collagen I and IV were altered expression patterns observed between KS and SCO patients. In peripubertal samples, no statistically significant differences were observed in the maturation markers, but altered ECM patterns were already present in some samples.

CONCLUSION(S)

The role of loss of ACTA2 expression in PTMC in the disintegration of tubules in KS patients should be further investigated. Future research is necessary to identify the causes of testicular fibrosis in KS patients. If the mechanism behind this fibrotic process could be identified, this process might be altered toward increasing the chances of fertility in KS patients.

3, 3', 5-Triiodo-L-thyronine affects polarity proteins of bovine Sertoli cells via WT1/non-canonical Wnt signaling pathway

To determine the role of 3, 3', 5-triiodo-L thyroxine (T3) in the differentiation of Sertoli cells (SCs) and the factors influencing maturity via the Wilms' tumor 1 (WT1)/non-canonical Wnt signaling pathway, high purity SCs were isolated from newborn calves' testes and cultured in vitro. The SCs were stimulated with T3, and co-treated with short interference (si) RNA to knockdown endogenous WT1 and non-canonical Wnt signalling inhibitor Wnt-c59. Our results suggested that the addition of different concentrations (0, 25, 50, and 100 nM) of T3 in the culture medium changed the expression of KRT-18 (SCs immature marker) and accelerated the differentiation of SCs. T3 (100 nM) treatment induced up-regulated expression of WT1 over time (p < 0.05), while the expression of polarity proteins (Par3, Par6b, and E-cadherin) and Wnt4 were affected to varying degrees (p < 0.05). SCs were treated simultaneously with T3 + Wnt-c59 and T3 + WT1 siRNA, and the results showed that T3 could affect the expression of polarity proteins via WT1/non-canonical Wnt signaling pathway. These data put together indicate that T3 plays a dependent role in the induction of bovine SCs differentiation via WT1/non-canonical Wnt signaling pathway in vitro. This study proposes for the first time that WT1 is a major target for T3.

Identification of Proliferative and Apoptotic Sertoli Cells Using Fluorescence and Confocal Microscopy

Sertoli cells, the testicular somatic cells of the seminiferous epithelium, are vital for the survival of the epithelium. They undergo proliferation and apoptosis during fetal, neonatal, and prepubertal development. Apoptosis is increased in certain situations such as exposure to many substances, for example, toxics, or short photoperiod in the non-breeding season of some mammals. Therefore, it has always been considered that Sertoli cells that reach adulthood are quiescent cells, that is to say, nonproliferative, do not die, are terminally differentiated, and whose numbers remain constant. Recently, a degree of both proliferation and apoptosis has been observed in normal adult conditions, suggesting that consideration of this cell as quiescent may be subject to change. All this make it necessary to use histochemical techniques to demonstrate whether Sertoli cells are undergoing proliferation or apoptosis in histological sections and to allow the qualitative and quantitative study of these. In this chapter, we present two double-staining techniques that can be used for identifying Sertoli cells in proliferation or apoptosis by fluorescence microscopy. In both, the Sertoli cells are identified by an immunohistochemistry for vimentin followed by an immunohistochemistry for PCNA or a TUNEL histochemistry.

Defective Wnt3 expression by testicular Sertoli cells compromise male fertility

Testicular Sertoli cells make a niche for the division and differentiation of germ cells. Sertoli cells respond to increased follicle-stimulating hormone (FSH) and testosterone (T) levels at the onset of puberty by producing paracrine factors which affect germ cells and trigger robust onset of spermatogenesis. Such paracrine support to germ cells is absent during infancy, despite Sertoli cells being exposed to high FSH and T within the infant testis. This situation is similar to certain cases of male idiopathic infertility where post-pubertal Sertoli cells fail to support germ cell division and differentiation in spite of endogenous or exogenous hormonal support. Defective Sertoli cells in such individuals may fail to express the full complement of their paracrine repertoire. Identification and supplementation with such factors may overcome Sertoli cells deficiencies and help trigger quantitatively and qualitatively normal differentiation of germ cells. To this end, we compared the transcriptome of FSH- and T-treated infant and pubertal monkey Sertoli cells by DNA microarray. Expression of Wnt3, a morphogen of the Wnt/β-catenin pathway, was higher in pubertal Sertoli cells relative to infant Sertoli cells. Transgenic mice were generated by us in which Wnt3 expression was curtailed specifically in post-pubertal Sertoli cells by shRNA. Subfertility and oligozoospermia were noticed in such animals with low Wnt3 expression in post-pubertal Sertoli cells along with diminished expression of Connexin43, a gap-junctional molecule essential for germ cell development. We report that the FSH- and T-targetedf Wnt3 governs Sertoli cell-mediated regulation of spermatogenesis and hence is crucial for fertility.

Influence of prolonged flaxseed ( Linum usitatissimum ) consumption over epididymis and testicle histoarchitecture of Wistar rats

ABSTRACT: Flaxseed is considered a functional food with several health benefits. However, because of its high phytoestrogen content, flaxseed influences hormone metabolism and affects the gonadal biomorphology. In this study, computerized histomorphometry was used to evaluate seminiferous and epididymal tubules, considering the different regions of the epididymis (head, body and tail) of rats subjected to a prolonged diet of flaxseed. Young adult male Wistar rats (n=20) were divided into 2 groups during their lactation period: Control Group (CG), fed casein-based meals and Flaxseed Group (FG), fed a 25% flaxseed meal. After 250 days of continuous ingestion, the animals were euthanized and a blood sample was collected. The testicles and epididymis were removed and fixed in buffered formalin solution. The samples were subjected to routine histological paraffin techniques and stained with hematoxilin and eosin. Immunostaining was performed using an antivimentin antibody for Sertoli cell identification. For morphometry, images of the slides were scanned and analyzed using Image J to determine the epithelial height, tubular and luminal diameter and tubular and luminal area. In the hormonal evaluation, FG had a higher serum concentration of estrogen (P=0.001), but no change was observed in the concentration of testosterone. The morphometric assay of seminiferous tubules and epididymal regions revealed no significant differences between the analyzed groups. Similarly, Sertoli cell quantification showed no significant differences in the FG (P=0.98). These results revealed that the continuous and prolonged intake of 25% flaxseed meals from gestation to 250 days of age, even with a significant increase in serum levels of estradiol, does not exert adverse effects on the testicular and epididymal structure or on the cells participating in the spermatogenesis of rats.

Prevalence of small testicular hyperechogenic foci in subgroups of 382 non-vasectomized, azoospermic men: a retrospective cohort study

Testicular hyperechogenic foci (THF) are associated with Klinefelter's syndrome, cryptorchidism, infertility, and testicular germ cell neoplasia. The aims of the study were to evaluate THF in relation to etiology of azoospermia and to Sertoli cell dysfunction. The structures inside the scrotum of consecutive non‐vasectomized, azoospermic were examined by ultrasonography, and hormone (FSH, LH, testosterone, and prolactin), and genetic analyses (karyotype, Y microdeletions, and CFTR mutations) were performed. At testicular ultrasonography, patients were graduated into: pronounced THF (>7 THF per transducer field), distributed universally (uTHF) or collected in plaques (pTHF), borderline THF (bTHF; 3–7 THF per transducer field), or no THF (<3 THF per transducer field). Diagnostic testicular biopsy was taken open or with TruCut needle (14G). THF status was sufficiently described in 382 of 449 potential participants, and testicular histology was available in 300 cases. Presence of ultrasonographically detectable THF was compared to presence of testicular microlithiasis (TM) detected histologically. Sertoli cell dysfunction was investigated in a subgroup using a three‐stage immunoperoxidase technique for detection of cytokeratin‐18 (CK‐18). The prevalence of THF was 13.4%. uTHF was found in 11 men (2.9%), the pattern was bilateral in four while other four had bTHF in the other testis. pTHF was detected in eight cases (2.1%), and except for one case with Klinefelter's syndrome, pTHF was in all cases occurring unilaterally. bTHF was detected in 32 cases (8.4%), bilaterally in 17 (53%). Pronounced THF was significantly associated with testicular malignancy. CK‐18 was detected in more azoospermic men with sperm production in ≤50% seminiferous tubules than in azoospermic men with spermatogenesis in ≥90% of seminiferous tubules and normal controls (p < 0.05). Unfortunately, TM detected histologically was not detected in any patient expressing THF, and neither THF nor TM was detected in any of the patients examined for CK‐18. Sertoli cell dysfunction was not associated with testicular microlithiasis or hyperechogenic foci.

Possible germ cell-Sertoli cell interactions are critical for establishing appropriate expression levels for the Sertoli cell-specific MicroRNA, miR-202-5p, in human testis

Background

To examine human microRNA expression in fertile men and subsequently to compare expression patterns of miRNAs in fertile and infertile men, specifically men with Sertoli Cell Only (SCO) histopathology.

Methods

Testicular tissues from men with azoospermia and SCO, as well as those of men with normal spermatogenesis, were analyzed. MicroRNA was isolated using the miRCURY™ RNA Purification Kit. A miRCURY LNA™ Universal RT system was used for detection of microRNA by quantitative real-time PCR. MicroRNA localization was performed by in situ hybridizations (ISH) on formalin-fixed paraffin embedded (FFPE) tissue utilizing miRCURY LNA™ microRNA ISH technology. Statistical analysis was performed by GenEx V5.0.

Results

MicroRNA expression was determined for 13 normal fertile men and 5 men with the confirmed diagnosis of diffuse SCO. MiR-202-5p expression was reduced by 17-fold (P < 0.00001) in tissue from SCO men compared to normal. MiR-34c-5p was reduced by 346-fold (P < 0.00001), miR-10b was reduced 18-fold (P < 0.00001), miR-191 was reduced 20-fold (P = 0.001) and miR-126 was reduced 40-fold (P < 0.00001)) in tissues from SCO compared to normal fertile men. Using ISH, miR-202-5p was localized to Sertoli cells of men with normal spermatogenesis, but not in the Sertoli cells of men with SCO.

Conclusion

Number of miRNAs are differentially expressed in normal fertile men compared to men with SCO. MicroRNA-202-5p is localized to Sertoli cells and its expression dramatically differs between fertile men and men whose germ cells are depleted, suggesting a novel interaction for regulating microRNA expression between the somatic and germ cell components of the seminiferous epithelium.

Low levels of Gαs and Ric8b in testicular sertoli cells may underlie restricted FSH action during infancy in primates

FSH acts via testicular Sertoli cells (Sc) bearing FSH receptor (FSH-R) for regulating male fertility. Despite an adult-like FSH milieu in infant boys and monkeys, spermatogenesis is not initiated until the onset of puberty. We used infant and pubertal monkey Sc to reveal the molecular basis underlying developmental differences of FSH-R signaling in them. Unlike pubertal Sc, increasing doses of FSH failed to augment cAMP production by infant Sc. The expression of Gαs subunit and Ric8b, which collectively activate adenylyl cyclase (AC) for augmenting cAMP production and gene transcription, were significantly low in infant Sc. However, forskolin, which acts directly on AC bypassing FSH-R, augmented cAMP production and gene transcription uniformly in both infant and pubertal Sc. FSH-induced Gαs mRNA expression was higher in pubertal Sc. However, Gαi-2 expression was down-regulated by FSH in pubertal Sc, unlike infant Sc. FSH failed, but forskolin or 8-Bromoadenosine 3',5'-cyclic monophosphate treatment to infant Sc significantly augmented the expression of transferrin, androgen binding protein, inhibin-β-B, stem cell factor, and glial-derived neurotropic factor, which are usually up-regulated by FSH in pubertal Sc during spermatogenic onset. This suggested that lack of FSH mediated down-regulation of Gαi-2 expression and limited expression of Gαs subunit as well as Ric8b may underlie limited FSH responsiveness of Sc during infancy. This study also divulged that intracellular signaling events downstream of FSH-R are in place and can be activated exogenously in infant Sc. Additionally, this information may help in the proper diagnosis and treatment of infertile individuals having abnormal G protein-coupled FSH-R.

Could androgen receptor gene CAG tract polymorphism affect spermatogenesis in men with idiopathic infertility?

PURPOSE

This study examined whether the AR-CAG repeat length might affect clinical characteristics (testis volume) seminal parameters (sperm count and its mobility) along with hormonal serum profile [FSH, LH, Testosterone (T) and Inhibin B (InhB)] both in idiopathic male infertility (IM) and in infertility due to a previous condition of cryptorchidism (CryM) or to Y chromosome long arm microdeletions (YM).

DESIGN

Observational study without intervention(s).

PATIENTS

One hundred and ten IM patients [90 idiopathic olizoospermic males (IOM) and 20 idiopathic azoospermic males (IAM)], 19 CryM male and 10 YM patients were included. Sixty-one age-matched healthy men who had fathered within 3 years were involved representing the control group (FM).

RESULTS

AR-CAG repeats stretch was significantly longer in IOM (p<0.05), CryM (p<0.05) and YM (p<0.001) than FM. When the AR-CAG repeat tracts were subdivided in three subgroups according to the length of CAG repeats tract assessed in fertile subjects (the one with the middle (n 19-21) belonging to the 25 and 75 % inter-quartile, the ends belonging to the <25 % inter-quartile and >75 % inter-quartile, respectively), there was a statistically significant difference of distribution of AR-CAG tract length among fertile and different groups of infertile men (p=<0.0005; chi-square test). Moreover, the subgroup of AR-CAG repeat stretch with 22-28 triplets was associated with lower levels of InhB both in idiopathic oligozoospermic (Scheffe, Bonferroni and Dunett tests p=<0.01) and azoospermic men (Scheffe, Bonferroni and Dunett test p=<0.05), while, when FM and men with idiopathic infertility were gathered in a single group, both the subgroup of AR- CAG tract with 15-18 repeats and the one with 22-28 repeats are associated with lower testis volume, reduced sperm count and serum InhB levels.

CONCLUSIONS

Our study showed that the outliers of AR-CAG repeat length seem to influence the function of AR, affecting testis volume and Sertoli cell function and consequently sperm production in both fertile and idiopathic infertile men.

Claudin-11 and connexin-43 display altered spatial patterns of organization in men with primary seminiferous tubule failure compared with controls

OBJECTIVE

To assess the spatial organization of two proteins involved in the Sertoli cell junctional complex in men with primary seminiferous tubule failure.

DESIGN

Retrospective study.

SETTING

Medical research institute.

PATIENT(S)

Sixteen men total, six with meiotic arrest, seven with the Sertoli cell-only phenotype, and three with normal spermatogenesis.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Differences in claudin-11 and connexin-43 organization as detected using confocal microscopy.

RESULT(S)

In men with primary seminiferous tubule failure, four organizational patterns (I-IV) were recognized and quantified for claudin-11. Across these patterns, claudin-11 changed from a basal filamentous staining pattern to a punctate staining pattern with diffuse localization throughout the entire epithelium. Similar changes in staining patterns for connexin-43 were observed. Major differences were seen in the spatial organization of claudin-11 and connexin-43 in tubules from control men compared with tubules with primary seminiferous tubule failure, but we observed no differences in the spatial organization of these proteins in tubules from men with meiotic arrest and Sertoli cell-only phenotypes.

CONCLUSION(S)

The spatial organization of claudin-11 and connexin-43 is altered in men with primary seminiferous tubule failure. Disorganization of the proteins composing the Sertoli cell junctional complex may be involved in the spermatogenic impairment, possibly via loss of blood-testis barrier function.

Immunolocalization of cytoskeletal proteins in the testes of two Asian cervids: water deer (Hydropotes inermis) and Reeves' muntjac (Muntiacus reevesi)

In order to gather basic reproductive information of the water deer and Reeves' muntjac, the immunolocalization of the cytoskeleton proteins in the testes and epididymides of these two species was investigated. The distribution pattern of cytoskeletal proteins in these two species was similar. The desmin was detected in the peritubular myoid cells of the testes and the sub-epithelial cells of the epididymal ducts. Vimentin was observed in the myoid cells, Leydig cells and perinuclear region of the Sertoli cells. Intense immunoreactions for α-smooth muscle actin were restricted to the smooth vascular muscle cells and the peritubular myoid cells in the testes. From the present results, it appears that these distribution patterns of cytoskeletal proteins may be common in the cervids.

A Wt1-Dmrt1 transgene restores DMRT1 to sertoli cells of Dmrt1(-/-) testes: a novel model of DMRT1-deficient germ cells

DMRT1 is an evolutionarily conserved transcriptional factor expressed only in the postnatal testis, where it is produced in Sertoli cells and germ cells. While deletion of Dmrt1 in mice demonstrated it is required for postnatal testis development and fertility, much is still unknown about its temporal- and cell-specific functions. This study characterized a novel mouse model of DMRT1-deficient germ cells that was generated by breeding Dmrt1-null (Dmrt1(-/-)) mice with Wt1-Dmrt1 transgenic (Dmrt1(+/-;tg)) mice, which express a rat Dmrt1 cDNA in gonadal supporting cells by directing it from the Wilms tumor 1 locus in a yeast artificial chromosome transgene. Like Dmrt1(-/-) mice, male Dmrt1(-/-) transgenic mice (Dmrt1(-/-;tg)) were infertile, while female mice were fertile. Immunohistochemistry and Western blot analysis showed transgenic DMRT1 expressed in supporting cells of the newborn gonads of both sex and in Sertoli cells of the testis afterbirth. Sertoli cells were evaluated by electron microscopy, revealing that maturation of Dmrt1(-/-;tg) Sertoli cells was incomplete. Morphological analysis of testes from 42-day-old mice showed that, compared to Dmrt1(-/-) mice, Dmrt1(-/-;tg) mice have improved seminiferous tubule structure, with lumens present in many. Immunohistochemistry of the polarity markers ESPIN and NECTIN-2 showed that DMRT1 in Sertoli cells is required for NECTIN-2 expression and influences organization of ectoplasmic specializations. Further functional analyses of the transgene on a Dmrt1(-/-) background showed that it did not rescue the decrease in Dmrt1(-/-) testis size, but when expressed on a wild-type background, exogenous DMRT1 prevented the normal age-related decline in testis size and enhanced sperm progressive motility. The studies suggest that DMRT1 in Sertoli cells regulates tubule morphology, spermatogenesis, and sperm function via its effects on Sertoli cell maturation and polarity. Furthermore, expression and function of transgenic DMRT1 in Sertoli cells establishes a novel mouse model of DMRT1-deficient germ cells generated by breeding Dmrt1-null mice with Wt1-Dmrt1 transgenic mice (rescue; Dmrt1(-/-;tg)).

Expression of cytokeratin 10 protein in the human testis showing normal and abnormal spermatogenesis

BACKGROUND

CK10 is a heterotetramer of type I and two type II keratins.

AIM

This study examines the expression pattern of cytokeratin 10 (CK10) in human testis.

MATERIALS AND METHODS

CK10 protein expression was examined using immunofluorescense staining methods in 30 human testicular biopsy specimens (normal spermatogenesis, maturation arrest and Sertoli cell only syndrome, 10 cases each) obtained from patients undergoing investigations for infertility.

RESULTS

In the testis showing normal spermatogenesis, CK10 was expressed in the interstitium and in the seminiferous tubules. A strong cytoplasmic expression was seen in the Leydig cells, Sertoli cells, and spermatocytes. In testes showing spermatogenic arrest, weak CK10 protein expression was observed both in the interstitium and seminiferous tubules (some primary spermatocytes). In the testes showing Sertoli cell only syndrome, negligible CK10 staining was seen both in the seminiferous tubules and in the interstitial cells of Leydig.

CONCLUSIONS

To the authors' knowledge, this is the first study indicating CK10 expression in the human testis during normal and abnormal spermatogenesis. The varied expression of CK10 in testes showing abnormal spermatogenesis suggests its possible involvement in this process.

Reduced numbers of Sertoli, germ, and spermatogonial stem cells in impaired spermatogenesis

A key step in the investigation of male infertility is the appropriate classification of impaired spermatogenesis. In this study, we precisely identified Sertoli and distinct germ-cell types in the rat, the mouse, and in the human testis. As a proof of principle, we studied testis biopsy samples from azoospermic patients with defined spermatogenic defects. Remarkably, we found that already the numbers of Sertoli cells, spermatogonia and a subset of spermatogonia including stem cells are significantly reduced in patients with maturation arrest at the level of primary spermatocytes (n=33) compared with patients with histologically normal spermatogenesis (n=33). In patients with hypospermatogenesis (n=44) a significant reduction of spermatogonial cell numbers was observed. The numbers of primary and diplotene spermatocytes were reduced by 84%. However, the strongest reduction (96%) was revealed in the numbers of spermatids in patients with maturation arrest. In contrast, patients with hypospermatogenesis showed only modestly reduced numbers of spermatocytes and spermatids compared with normal spermatogenesis. No correlation was found with age or obstruction. For a detailed analysis of the patients, we distinguished between 'pool of founder cells'-related deficiencies (reduced numbers of Sertoli cells, spermatogonia, and spermatogonial stem cells) and 'meiotic' deficiencies (reduced numbers of spermatocytes, meiotic divisions, and spermatids). Interestingly, patients with maturation arrest showed meiotic deficiencies (36%), while the majority additionally demonstrated deficiencies in the founder pool (58%). In contrast, patients with normal spermatogenesis most often had no deficiencies at all (45%) or founder pool-related deficiencies (33%) but an apparently normal meiosis. This is the first report showing that many infertile patients face besides meiotic defects the problem of reduced numbers of Sertoli cells, spermatogonia, and spermatogonial stem cells.

Cytokeratin 18 expression in immature Sertoli cells: co-localization with interstitial lymphocytic infiltrates

Although multiple interactions of seminiferous tubules and the interstitial testicular tissue are known, correlation of cytokeratin 18 expressing Sertoli cells with interstitial changes has still not yet been reported. Considering this fact, we focused our investigation on changes of the adjacent interstitial tissue. A total sample of 51 testicular biopsies (from infertile patients) showing mixed atrophy was examined immunohistochemically with antibodies against cytokeratin 18, vimentin, L26/CD20, CD4 and CD8. Twenty-one of the 51 cases showed single seminiferous tubules with Sertoli cells expressing cytokeratin 18. These 21 tubules consistently exhibit either spermatogenic arrest at the level of spermatogonia or only immature Sertoli cells. In the adjacent interstitial tissue of 8 of the 21 cytokeratin 18 positive tubules (39%) striking inflammatory infiltrates--predominantly expressing L26/CD20 typical for B lymphocytes and CD8 typical for T suppressor lymphocytes--were detected. These findings underline that tubules with cytokeratin 18 expressing Sertoli cells exhibit early spermatogenic arrest or only few remaining Sertoli cells. Additionally, we observed a remarkable co-localization of these tubules with lymphocytic infiltrates of the adjacent interstitial tissue.

Primary testicular lesions are associated with testicular germ cell tumors of adult men

The present study aims to establish the nature and frequency of testicular lesions in the parenchyma adjacent to testicular germ cell tumors (TGCT) to improve understanding of the factors involved in the development of testicular cancer. Fifty-three cases of TGCT that were fixed in both neutral-buffered formalin and Bouin solution, allowing for the nuclear characterization of Sertoli cells (SCs), were included in this study. In each case, at least 3 sections of different areas of preserved parenchyma surrounding the TGCT were studied. We found Leydig cell hyperplasia, microlithiasis, angiopathy, adenomatous hyperplasia of the rete testis, SC nodules, SC dysgenesis and involution, SC-only tubules, tubular atrophy, adluminal compartment lesions, hypospermatogenesis associated with spermatocyte sloughing, spermatogonial maturation arrest, and hypertrophic and multinucleated spermatogonia. These lesions were found in regions both adjacent and far away from the tumoral mass, and abnormal seminiferous tubules were found intermingled with those showing complete spermatogenesis, suggesting that these lesions are primary and existed before the development of the tumor. Our study suggests that SCs might play a more important role in the development of testicular tumors than previously thought. Our data supports the hypothesis that there is an abnormal differentiation of SCs, caused either by genetic anomalies or by environmental agents during fetal life. This abnormal SC differentiation may cause not only primary spermatogenesis failure and spermatogenesis arrest at different levels, but may also contribute to the poor differentiation of gonocytes into spermatogonia. The abnormal gonocyte differentiation might favor the development of dysplastic germ cells that may later transform into intratubular germ cell neoplasia, unclassified type.

Adult sertoli cells are not terminally differentiated in the Djungarian hamster: effect of FSH on proliferation and junction protein organization

Sertoli cell number is considered to be stable and unmodifiable by hormones after puberty in mammals, although recent data using the seasonal breeding adult Djungarian hamster (Phodopus sungorus) model challenged this assertion by demonstrating a decrease in Sertoli cell number after gonadotropin depletion and a return to control levels following 7 days of FSH replacement. The present study aimed to determine whether adult Sertoli cells are terminally differentiated using known characteristics of cellular differentiation, including proliferation, junction protein localization, and expression of particular maturational markers, in the Djungarian hamster model. Adult long-day (LD) photoperiod (16L:8D) hamsters were exposed to short-day (SD) photoperiod (8L:16D) for 11 wk to suppress gonadotropins and then received exogenous FSH for up to 10 days. Sertoli cell proliferation was assessed by immunofluorescence by the colocalization of GATA4 and proliferating cell nuclear antigen and quantified by stereology. Markers of Sertoli cell maturation (immature, cytokeratin 18 [KRT18]; mature, GATA1) and junction proteins (actin, espin, claudin 11 [CLDN11], and tight junction protein 1 [TJP1, also known as ZO-1]) also were localized using confocal immunofluorescence. In response to FSH treatment, proliferation was upregulated within 2 days compared with SD controls (90% vs. 0.2%, P < 0.001) and declined gradually thereafter. In LD hamsters, junction proteins colocalized at the basal aspect of Sertoli cells, consistent with inter-Sertoli cell junctions, and were disordered within the Sertoli cell cytoplasm in SD animals. Exogenous FSH treatment promptly restored localization of these junction markers to the LD phenotype. Protein markers of maturity remain consistent with those of adult Sertoli cells. It is concluded that adult Sertoli cells are not terminally differentiated in the Djungarian hamster and that FSH plays an important role in governing the differentiation process. It is proposed that Sertoli cells can enter a transitional state, exhibiting features common to both undifferentiated and differentiated Sertoli cells.

Postnatal Developmental Changes in Immunohistochemical Localization of .ALPHA.-Smooth Muscle Actin (SMA) and Vimentin in Bovine Testes

The present study demonstrates the postnatal developmental changes in immunohistochemical localization of alpha-smooth muscle actin (SMA) and vimentin in the bovine testis. In the peritubular myoid cells of seminiferous tubules and the sub-epithelial and stromal cells of straight tubules and the rete testis, alpha-SMA starts appearing at around 4 months of age. Peritubular alpha-SMA attains the continuous mature pattern at around 5 months of age whereas sub-epithelial and stromal alpha-SMA increases with advancing age. Vimentin is localized in the perinuclear zone of Sertoli cells, peritubular and vascular wall cells, a few interstitial cells, and in the basal part of the epithelia of straight and rete tubules. Developmental changes are only evident in the Sertoli cell vimentin, which is basal and weak at birth and increases moderately until 4 months of age. From around 5 to 8 months of age when the Sertoli cells are under morphological transformation, vimentin intensity is considerably increased and the characteristic vimentin extensions connect the Sertoli nuclei to the basal membrane. These extensions get shorter at around 9 month of age as the Sertoli nuclei are positioned basally. The mature Sertoli cell perinuclear vimentin is strong and stable without infranuclear extension. In conclusion, the age of appearance of alpha-SMA coincides with the onset of postnatal division of spermatogonia, and vimentin may play a key role in stabilizing Sertoli cell nuclei during their transformation in bovine.

Detection of calretinin expression in abnormal immature Sertoli cells in non-obstructive azoospermia

The current study identified for the first time calretinin expression in abnormal Sertoli cells of azoospermic men who underwent testicular biopsy for sperm recovery and application of the retrieved sperm by in vitro fertilization techniques. Testicular biopsies with various spermatogenic impairments were evaluated immunohistochemically for the expression of the calretinin calcium-binding protein and the marker for immaturity of Sertoli cells, cytokeratin-18 (CK-18). Distribution of the markers was assessed in testes demonstrating a histological phenotype of mixed atrophy, Sertoli cell-only, or normal spermatogenesis (obstructive-azoospermia) and in men carrying a deletion in the azoospermia factor region located on the Y chromosome. Calretinin-immunopositive immature Sertoli cells revealed by co-localization of both markers, calretinin and CK-18, were identified in the mixed atrophy group in seminiferous tubules demonstrating spermatogenic failure. Sertoli cells expressing both markers were rarely detected in all other groups. Leydig cells in all the assessed biopsies expressed calretinin and served as a built-in control for immunoreactivity. This pattern of calretinin-selective expression in immature Sertoli cells suggests a functional relationship between calretinin expression and the degree of Sertoli cell differentiation. Disorders of Sertoli cell differentiation as indicated by calretinin and/or CK-18 expression contribute to the multifactorial mechanisms underlying spermatogenic failure.

Susceptibility gene for non-obstructive azoospermia in the HLA class II region: correlations with Y chromosome microdeletion and spermatogenesis

We previously reported an association between the human leukocyte antigen (HLA) haplotype DRB1*1302-DQB1*0604 in the HLA class II region and non-obstructive azoospermia in Japanese men. To identify possible associations between the HLA-DRB1*1302-DQB1*0604 allele in the HLA class II region and azoospermia factor (AZF) deletion in the Y chromosome, we performed genomic polymerase chain reaction (PCR) analysis of the AZF region. We then determined spermatogenic impairment (Johnsen score) in testicular biopsy specimens from patients with or without the DRB1*1302-DQB1*0604 haplotype. The AZF microdeletion rate in patients with this haplotype was 3.85%, compared with 11.8% in others (no correlation). However, Johnsen scores in patients with the DRB1*1302-DQB1*0604 haplotype were 3.13 +/- 1.34 (mean +/- SD), compared with 3.70 +/- 1.51 in others (p < 0.05). While the DRB1*1302-DQB1*0604 haplotype acts independently from Y chromosome deletion, the haplotype might either act directly, or be functionally related to an unknown autosomal gene. In either case, this haplotype showed association with severe spermatogenic impairment.

Disrupted expression of intermediate filaments in the testis of rhesus monkey after experimental cryptorchidism

Cytoskeletons in Sertoli cell play an important role in process of spermatogenesis. The expression and distribution of the intermediate filaments, vimentin, keratin and desmin, were studied in the Sertoli cells of the cryptorchid testis of rhesus monkey. Vimentin was localized in the perinuclear region of Sertoli cells of the normal testis. An intense increase in vimentin immunoreactivity was observed with appearance of disorganized staining in the Sertoli cells of the cryptorchid testes. Cytokeratin 18, a marker of immature Sertoli cells, re-expressed in the cells of the adult cryptorchid testes. Desmin was also observed in the Sertoli cells in addition to the peritubular myoid cells on 30 days after the cryptorchid operation. These data suggest that Sertoli cells in primate can be affected by the heat stress. The altered changes in intermediate filaments could be possible to induce the Sertoli cell functional changes that would partially contribute to the germ cell apoptosis leading to azoospermia or oligozoospermia.

Sertoli cell inactivation by cytotoxic damage to the human testis after cancer chemotherapy

OBJECTIVE

To assess Sertoli cell involvement in postchemotherapy azoospermia.

DESIGN

Case report.

SETTING

Teaching hospital.

PATIENT(S)

A 31-year-old azoospermic man who underwent cancer cytotoxic chemotherapy for non-Hodgkin's lymphoma at 13 years of age.

INTERVENTION(S)

Testicular biopsy specimens were obtained for sperm recovery in preparation for intracytoplasmic sperm injection. The biopsy specimens were evaluated by quantitative immunohistochemistry for the immature Sertoli cell markers cytokeratin 18 (CK-18) and D2-40.

MAIN OUTCOME MEASURE(S)

Extent of immature Sertoli cells.

RESULT(S)

A fraction of Sertoli cells (13%) in the atrophic tubules of this patient reexpressed the intermediate filament protein CK-18, which is normally absent after puberty, but not the D2-40 antigen, an Mr 40,000 a-linked membrane glycoprotein, whose loss of expression at puberty marks an irreversible step in Sertoli cell maturation. Tubules with normal spermatogenic progression lined by Sertoli cells negative for CK-18 were also observed.

CONCLUSION(S)

A fraction of Sertoli cells of this patient initially progressed to full maturation at puberty and reverted to a dedifferentiated state marked by reexpression of CK-18 as a consequence of chemotherapy. This inactivation of Sertoli cells caused by the cytotoxicity of the chemotherapeutic drugs may have contributed to the spermatogenic impairment and resulting infertility.

Spermatogonial proliferation patterns in men with azoospermia of different etiologies

OBJECTIVE

To demonstrate the pattern(s) of spermatogonial proliferation in different spermatogenic disorders.

DESIGN

Retrospective case-control study. Teaching hospital.

PATIENT(S)

Azoospermic men who underwent testicular biopsy for sperm recovery and preparation for intracytoplasmic sperm injection.

INTERVENTION(S)

Testicular biopsy evaluation by quantitative immunohistochemistry for proliferating cell nuclear antigen (PCNA).

MAIN OUTCOME MEASURE(S)

The expression of PCNA in spermatogonia as an index of proliferating activity in testes with focal spermatogenesis, spermatocyte maturation arrest, or normal spermatogenesis.

RESULT(S)

In biopsies with focal spermatogenesis (11 men), there was a statistically significant reduction of PCNA-labeled spermatogonia in seminiferous tubules showing spermatocyte arrest compared with the expression in adjacent tubules with advanced spermatogenic stage or in normal spermatogenesis (obstructive azoospermia, six men). However, PCNA expression in tubules of the group with complete maturation arrest (six men) was significantly higher compared with the same spermatogenic defect-spermatocyte arrest-within focal spermatogenesis biopsies.

CONCLUSION(S)

Different causes underlie the spermatogenic disorders reported in this study. In focal spermatogenesis, the disorder is associated with the presence of mitotic inactive spermatogonia. The detection of normal active spermatogonia in the spermatocyte arrest group indicates that the spermatogenic defect, which is accompanied by meiosis impairment, is not related to a malfunction of spermatogonial proliferation.

Impaired gap junction connexin43 in Sertoli cells of patients with secretory azoospermia: a marker of undifferentiated Sertoli cells

Gap junctions are intercellular channels formed of connexins (Cx) at appositional plasma membranes between adjacent cells that have been involved in the control of cell proliferation and differentiation. Altered Cx expression is implicated consistently in several human diseases and in tumorigenesis. Although Cx43 plays a critical role in Sertoli cell control of spermatogenesis, there is no evidence of its altered expression in human testicular pathologies. We show here that Cx43 mRNA expression was significantly reduced in testes of infertile patients with secretory azoospermia (p < 0.05) compared with testes displaying normal spermatogenesis (excretory azoospermic patients). In Sertoli cell-only syndrome, in situ hybridization and immunohistochemistry analyses indicated that Cx43 mRNA and protein were undetectable in Sertoli cells but were still present in the interstitial compartment. In a rat model of Sertoli cell-only syndrome, the lack of Cx43 in Sertoli cells was associated with an impairment of gap junction intercellular communication between adjacent Sertoli cells. These results reveal that Cx43 mRNA and protein expression are markedly impaired in Sertoli cells of infertile patients. This defect could be a new functional marker of undifferentiated Sertoli cells and could be related to the increased risk of testicular cancer recently described in the population of infertile men.

Altered expression of connexins 26 and 43 in Sertoli cells in seminiferous tubules infiltrated with carcinoma-in-situ or seminoma

The expression of connexins (cx) 26 and 43 in testis infiltrated with carcinoma-in-situ (CIS) or seminoma was examined to gain insight into the relationship between aberrant gap junctional communication and spermatogenic impairment in the neoplastic testis. In uninvolved tubules with normal spermatogenesis, cx43 immunostaining was localized to the Sertoli-Sertoli junctional complex and cx26 was absent. In contrast, infiltrated tubules with spermatogonial arrest or CIS-only were negative for cx43, but displayed strong intracytoplasmic Sertoli cell staining for cx26. The Sertoli cells in these tubules re-expressed cytokeratin 18 (ck18), signifying a reversion to a less differentiated state. Western blot analysis for cx43 revealed a single immunoreactive band at 43 kD (normal spermatogenesis) and three bands at 43, 41, and 39 kD (impaired spermatogenesis with CIS or seminoma). For cx26, a doublet band at 26/28 kD (normal spermatogenesis) and an additional doublet band at 52/54 kD (impaired spermatogenesis with CIS or seminoma) were observed. The altered expression of cx26 and cx43 in Sertoli cells in testes infiltrated with CIS or seminoma suggests that a derangement in intercellular communication between Sertoli cells and between Sertoli cells and germ cells may play a role in the resulting spermatogenic impairment and possibly in the proliferation and neoplastic progression of CIS cells.

Sertoli cell maturation in men with azoospermia of different etiologies

OBJECTIVE

To evaluate the involvement of Sertoli cell in different spermatogenic disorders.

DESIGN

Retrospective case-control study.

SETTING

Teaching hospital.

PATIENT(S)

Azoospermic men who underwent testicular biopsy for sperm recovery in preparation for intracytoplasmic sperm injection.

INTERVENTION(S)

Testicular biopsy evaluation by quantitative immunohistochemistry for the immature Sertoli cell markers anti-Müllerian hormone and cytokeratin 18 (CK-18).

MAIN OUTCOME MEASURE(S)

Relative area of immature Sertoli cells in testes with focal spermatogenesis, spermatocyte maturation arrest, or normal spermatogenesis.

RESULT(S)

The relative area occupied by immature Sertoli cells, as revealed by anti-Müllerian hormone and CK-18 expression, was highest in the 11 men with focal spermatogenesis. In the group representing normal spermatogenesis (obstructive azoospermia, 6 men) and in the group characterized by spermatocyte maturation arrest (6 men), the areas occupied by anti-Müllerian hormone- and CK-18-positive cells were minimal.

CONCLUSION(S)

Different etiologies underlie the spermatogenic disorders reported in this study. In focal spermatogenesis with high anti-Müllerian hormone and CK-18 expression, the spermatogenic impairment is associated with the presence of immature Sertoli cells. The detection of normal mature Sertoli cells in the spermatocyte maturation arrest group indicates that the spermatogenic defect that is accompanied by an impairment of meiosis is intrinsic to the germ line without affecting Sertoli cell differentiation.

Immunohistochemistry in the evaluation of spermatogenesis and Sertoli cell's maturation status

An increasing incidence of male infertility has been noted over the past few decades. This adds urgency to the need to develop immunohistochemical markers for better evaluation of testicular biopsies. We provide evidence that a histopathological evaluation performed according to morphological criteria and assisted by immunohistochemical staining on consecutive sections enhances the sensitivity and accuracy of the diagnosis based on testicular biopsies from infertile men.

The contribution of RNA-binding motif (RBM) antibody to the histopathologic evaluation of testicular biopsies from infertile men

Testicular biopsies of infertile men are often characterized by mixed histologic patterns, with different types of spermatogenic impairments being found in adjacent seminiferous tubules. RNA-binding motif (RBM) is a nuclear protein expressed exclusively in the male germ cell line. We reasoned that RBM might be a useful marker to identify germ cells in testicular sections, particularly in biopsies with mixed histologic phenotype and small focal concentrations of spermatogenesis. Testicular biopsies from azoospermic men were immunohistochemically evaluated for RBM expression. RBM expression was detectable in spermatogonia, spermatocytes, and round spermatids in biopsies of men with obstructive azoospermia and normal spermatogenesis. No specific cell staining was shown in cases of Sertoli-cell-only (SCO) syndrome. In biopsies of patients with spermatogenic disorders, all the germ cells were stained up to and including the stage level of the arrest in spermatogenesis. This approach enabled identification of small focal concentrations of spermatogenesis in a biopsy previously classified as being SCO by hematoxylin and eosin staining. Thus, RBM can be a useful immunohistochemical marker for the specific identification of germ cells and provide greater accuracy in the histopathologic evaluation of testicular biopsies.