Sertoli cell-only syndrome: advances, challenges, and perspectives in genetics and mechanisms.

Male infertility can be caused by quantitative and/or qualitative abnormalities in spermatogenesis, which affects men's physical and mental health. Sertoli cell-only syndrome (SCOS) is the most severe histological phenotype of male infertility characterized by the depletion of germ cells with only Sertoli cells remaining in the seminiferous tubules. Most SCOS cases cannot be explained by the already known genetic causes including karyotype abnormalities and microdeletions of the Y chromosome. With the development of sequencing technology, studies on screening new genetic causes for SCOS are growing in recent years. Directly sequencing of target genes in sporadic cases and whole-exome sequencing applied in familial cases have identified several genes associated with SCOS. Analyses of the testicular transcriptome, proteome, and epigenetics in SCOS patients provide explanations regarding the molecular mechanisms of SCOS. In this review, we discuss the possible relationship between defective germline development and SCOS based on mouse models with SCO phenotype. We also summarize the advances and challenges in the exploration of genetic causes and mechanisms of SCOS. Knowing the genetic factors of SCOS offers a better understanding of SCO and human spermatogenesis, and it also has practical significance for improving diagnosis, making appropriate medical decisions, and genetic counseling. For therapeutic implications, SCOS research, along with the achievements in stem cell technologies and gene therapy, build the foundation to develop novel therapies for SCOS patients to produce functional spermatozoa, giving them hope to father children.

MALDI Imaging Mass Spectrometry Reveals Lipid Alterations in Physiological and Sertoli Cell-Only Syndrome Human Testicular Tissue Sections.

Azoospermia, the absence of sperm cells in semen, affects around 15% of infertile males. Sertoli cell-only syndrome (SCOS) is the most common pathological lesion in the background of non-obstructive azoospermia and is characterised by the complete absence of germinal epithelium, with Sertoli cells exclusively present in the seminiferous tubules. Studies have shown a correlation between successful spermatogenesis and male fertility with lipid composition of spermatozoa, semen, seminal plasma or testis. The aim of this research was to discover the correlation between the Johnsen scoring system and phospholipid expressions in testicular cryosections of SCOS patients. MALDI imaging mass spectrometry is used to determine spatial distributions of molecular species, such as phospholipids. Phosphatidylcholines (PCs), phosphatidylethanolamines (PEs) and sphingomyelins (SMs) are the most abundant phospholipids in mammalian cells and testis. SMs, the structural components of plasma membranes, are crucial for spermatogenesis and sperm function. Plasmalogens, are unique PCs in testis with strong antioxidative properties. This study, using imaging mass spectrometry, demonstrates the local distribution of phospholipids, particularly SMs, PCs, plasmalogens and PEs in human testicular samples with SCOS for the first time. This study found a strong relationship between the Johnsen scoring system and phospholipid expression levels in human testicular tissues. Future findings could enable routine diagnostic techniques during microTESE procedures for successful sperm extraction.

Testis cell pyroptosis mediated by CASP1 and CASP4: possible sertoli cell-only syndrome pathogenesis.

BACKGROUND: Sertoli cell-only syndrome (SCOS) is the most serious pathological type of non-obstructive azoospermia. Recently, several genes related to SCOS have been identified, including FANCM, TEX14, NR5A1, NANOS2, PLK4, WNK3, and FANCA, but they cannot fully explain the pathogenesis of SCOS. This study attempted to explain spermatogenesis dysfunction in SCOS through testicular tissue RNA sequencing and to provide new targets for SCOS diagnosis and therapy. METHODS: We analyzed differentially expressed genes (DEGs) based on RNA sequencing of nine patients with SCOS and three patients with obstructive azoospermia and normal spermatogenesis. We further explored the identified genes using ELISA and immunohistochemistry. RESULTS: In total, 9406 DEGs were expressed (Log2|FC|≥ 1; adjusted P value < 0.05) in SCOS samples, and 21 hub genes were identified. Three upregulated core genes were found, including CASP4, CASP1, and PLA2G4A. Thus, we hypothesized that testis cell pyroptosis mediated by CASP1 and CASP4 might be involved in SCOS occurrence and development. ELISA verified that CASP1 and CASP4 activities in the testes of patients with SCOS were significantly higher than those in patients with normal spermatogenesis. Immunohistochemical results showed that CASP1 and CASP4 in the normal spermatogenesis group were mainly expressed in the nuclei of spermatogenic, Sertoli, and interstitial cells. CASP1 and CASP4 in the SCOS group were mainly expressed in the nuclei of Sertoli and interstitial cells because of the loss of spermatogonia and spermatocytes. CASP1 and CASP4 expression levels in the testes of patients with SCOS were significantly higher than those in patients with normal spermatogenisis. Furthermore, the pyroptosis-related proteins GSDMD and GSDME in the testes of patients with SCOS were also significantly higher than those in control patients. ELISA also showed that inflammatory factors (IL-1 ß, IL-18, LDH, and ROS) were significantly increased in the SCOS group. CONCLUSIONS: For the first time, we found that cell pyroptosis-related genes and key markers were significantly increased in the testes of patients with SCOS. We also observed many inflammatory and oxidative stress reactions in SCOS. Thus, we propose that testis cell pyroptosis mediated by CASP1 and CASP4 could participate in SCOS occurrence and development.

Evaluation of cell-free seminal mRNA for the diagnosis of obstruction as the cause of azoospermia in infertile men: A prospective cohort study.

Differentiating obstructive (OA) from non-obstructive (NOA) azoospermia is clinically important in managing infertile men. Classically, the differentiation has been based on clinical, hormonal and histological analysis. Histological tests are invasive and may miss spermatogenic areas. Seminal fluid can serve as a medium to assess the status of spermatogenesis and presence or absence of certain markers can help diagnosing and differentiating azoospermia. We evaluated the role of cell-free seminal markers: DDX4, PRM1 and PRM2 in diagnosing and differentiating between OA and NOA and classifying their subtypes. We observed DDX4 was more sensitive for NOA compared with OA. Among various subtypes of NOA, DDX4 positivity was higher in patients with maturation arrest and hypospermatogenesis compared with Sertoli cell only syndrome. PRM1 and PRM2 had very low positivity rate for any meaningful comparison. Seminal cell-free markers can serve as non-invasive tests in diagnosing and differentiating etiologies of azoospermia but their validity needs to be proved in long-term trials with more refined molecular techniques.

Sertoli cell-only syndrome: etiology and clinical management.

Almost 50% of infertility cases are due to male factors, and spermatogenesis failure is one of the most severe forms of male infertility. Sertoli cell-only syndrome (SCOS) also known as germ cell aplasia is characterized by azoospermia in which the seminiferous tubules of testicular biopsy are lined only with Sertoli cells. The definitive diagnosis of SCOS is by diagnostic testicular biopsy. Although SCOS may be a result of Klinefelter syndrome, most of the SCOS men have a normal karyotype. Along with genetic aberrations, signaling pathways and endocrine processes might be major factors in the development of SCOS. Sperm retrieval and intracytoplasmic sperm injection (ICSI) are available treatments for SCOS. However, some SCOS patients do not have therapeutic options to help them having a biological child. This review aims to summarize our present knowledge about SCOS and to highlight the importance of future researches in the diagnosis and treatment of this disorder.

Expression and localization of retinoid receptors in the testis of normal and infertile men.

Retinoic acid (RA), the active metabolite of vitamin A, is one of the most important factors regulating spermatogenesis. RA activates downstream pathways through its receptors (retinoic acid receptor alpha [RARA], retinoic acid receptor beta, and retinoic acid receptor gamma [RARG]) and retinoid X receptors (retinoid X receptor alpha [RXRA], retinoid X receptor beta [RXRB], and retinoid X receptor gamma [RXRG]). These receptors may serve as therapeutic targets for infertile men. However, the localization and expression of retinoid receptors in normal and infertile men were unknown. In this study, we found RARA and RARG were mostly localized in spermatocytes and round spermatids, RXRB was mainly expressed in Sertoli cells, and RXRG was expressed in most cell types in the fertile human testis. The localization of RARA, RARG, RXRB, and RXRG in men with hypospermatogenesis (HYPO) was similar to that of men with normal fertility. In addition, the messenger RNA expression levels of RARA, RARG, RXRA, RXRB, and RXRG were significantly decreased in men with Sertoli cell-only syndrome (SCOS) and maturational arrest (MA), but not in men with HYPO. These results suggest that reduced levels of RARA, RARG, RXRB, RXRA, and RXRG are more closely associated with SCOS and MA spermatogenetic failure. These results could contribute to the development of new molecular indicators of spermatogenic dysfunction and might provide novel therapeutic targets for treating male infertility.

Ran-binding protein 3 is associated with human spermatogenesis and male infertility.

Ran-binding protein 3 (RanBP3) is a Ran-interacting protein, which participates in the Ran GTPase system in cancer cell biology. However, the expression pattern and physiological role of RanBP3 remain largely unknown. In this study, we found that RanBP3 was expressed in human testes and localised to spermatogonium and spermatocyte of germ cells. In subcellular structure, its localisation is in the nucleus and cytoplasm. Interestingly, compared with normal groups, RanBP3 expression was lower in groups of patients with Maturation Arrest (MA) and Sertoli cell-only syndrome (SCO) when considered by the Johnson Score. RanBP3 expression in the MA group and SCO groups was dramatically lower than that in the normal control group. Studies have shown that RanBP3, which is one of the helper factors of Ran, is mainly participate in the nucleocytoplasmic transport of cells. RanBP3 helps Ran to achieve some functions such as nucleocytoplasmic transport, spindle assembly during mitosis and nuclear assembly after mitosis. Consequent changes in the expression of RanBP3 may associate with human spermatogenesis disorders and male infertility. The identification and characterisation of RanBP3 enhances our understanding of the molecular mechanisms underpinning its function in human spermatogenesis and male infertility.

Decreased expression of MRE11 and RAD50 in testes from humans with spermatogenic failure.

PURPOSE: To assess testicular mRNA and protein expression levels of MRE11 and RAD50 in human azoospermia patients. METHODS: Patients diagnosed with maturation arrest at the spermatocyte stage (MA) and Sertoli cell-only syndrome (SCOS) were recruited through diagnostic testicular biopsy. Patients with normal spermatogenesis were studied as controls. In addition, knockdown of MRE11 and RAD50 was performed in GC-2spd(ts) cells to investigate their roles in cellular proliferation and apoptosis. RESULTS: mRNA and protein expression levels of MRE11 and RAD50 were measured using quantitative polymerase chain reaction, western blotting, and immunohistochemistry, respectively. Knockdown of both MRE11 and RAD50 utilized transfection with small interfering RNAs. CONCLUSION: Our findings demonstrated altered expression levels of MRE11 and RAD50 in human testes with MA and SCOS, and showed that these alterations might be associated with impaired spermatogenesis. These results offer valuable new perspectives into the molecular mechanisms of male infertility.

From exome analysis in idiopathic azoospermia to the identification of a high-risk subgroup for occult Fanconi anemia.

PURPOSE: In about 10% of patients affected by Fanconi anemia (FA) the diagnosis is delayed until adulthood, and the presenting symptom in these "occult" FA cases is often a solid cancer and cancer treatment-related toxicity. Highly predictive clinical parameter(s) for diagnosing such an adult-onset cases are missing. METHODS: (1) Exome sequencing (ES), (2) Sanger sequencing of FANCA, (3) diepoxybutane (DEB)-induced chromosome breakage test. RESULTS: ES identified a pathogenic homozygous FANCA variant in a patient affected by Sertoli cell-only syndrome (SCOS) and in his azoospermic brother. Although they had no overt anemia, chromosomal breakage test revealed a reverse somatic mosaicism in the former and a typical FA picture in the latter. In 27 selected SCOS cases, 1 additional patient showing compound heterozygous pathogenic FANCA variants was identified with positive chromosomal breakage test. CONCLUSION: We report an extraordinarily high frequency of FA in a specific subgroup of azoospermic patients (7.1%). The screening for FANCA pathogenic variants in such patients has the potential to identify undiagnosed FA before the appearance of other severe clinical manifestations of the disease. The definition of this high-risk group for "occult" FA, based on specific testis phenotype with mild/borderline hematological alterations, is of unforeseen clinical relevance.

Disordered APC/C-mediated cell cycle progression and IGF1/PI3K/AKT signalling are the potential basis of Sertoli cell-only syndrome.

The cause of Sertoli cell-only syndrome (SCOS), a condition in which only Sertoli cells line the seminiferous tubules in the testis, is unknown. Three microarray data sets were downloaded from public databases and were used to compare SCOS and control group. A total of 291 genes differentially expressed (Log2 |FC| ≥ 1 and adjusted p value < 0.05) in SCOS patients. Further 238 genes were significantly downregulated, and 53 genes were significantly upregulated. To identify the hub genes in the differentially expressed genes, we constructed a protein-protein interaction network, and CCNB1, CCNA2, AURKA, KIF11, CCNB2, CDC6, PRC1, NCAPG, KIF2C and PLK4 were screened from the network for the downregulated genes. Since the upregulated genes could not form a network, we concentrated on the genes with a higher fold change, and CPA3, NFIB, LONRF2, LYVE1, ATP8B4, IGF1, ITPR1 and PLAT were identified as the top 50% fold change genes in any of the three microarray data sets. Among downregulated hub genes, CDC6, CCNA2, CCNB1 and CCNB2 were involved in APC/C-mediated cell cycle progression. Among key upregulated genes, IGF1 was involved in the PI3K/AKT pathway, while the other genes have not been reported in Sertoli or Leydig cells. In conclusion, SCOS appears to be caused by disordered APC/C-mediated cell cycle progression and PI3K/AKT signalling.

Duplications in 19p13.3 are associated with male infertility.

PURPOSE: To identify genomic imbalances and candidate loci in idiopathic male infertility. METHODS: Affymetrix CytoScan 750K Array was used to analyze genomic imbalances and candidate loci in 34 idiopathic infertile cases of different phenotypes (hypo-spermatogenesis, n = 8; maturation arrest, n = 7; and Sertoli cell-only syndrome, n = 13, severe oligozoospermia, n = 6, and 10 normozoospermic fertile men). Ten ethnically matched controls were screened for comparison. RESULTS: The cytogenetic array analysis detected a genomic gain at the 19p13.3 region in 9 (26.47%) cases, with the highest frequency in patients with Sertoli cell-only syndrome (SCOS) (38%). Its complete absence in the control group suggests its likely pathogenic nature. In addition to Y-classical, micro, and partial deletions, the duplication in 19p13.3 could serve as a unique biomarker for evaluation of infertility risk. The common region across the individuals harboring the duplication identified STK11, ATP5D, MIDN, CIRBP, and EFNA2 genes which make them strong candidates for further investigations. The largest duplicated region identified in this study displayed a major network of 7 genes, viz., CIRBP, FSTL3, GPX4, GAMT, KISS1R, STK11, and PCSK4, associated with reproductive system development and function. The role of chance was ruled out by screening of ethnically matched controls. CONCLUSION: The result clearly indicates the significance of 19p13.3 duplication in infertile men with severe testicular phenotypes. The present study underlines the utility and significance of whole genomic analysis in the cases of male infertility which goes undiagnosed due to limitations in the conventional cytogenetic techniques and for identifying genes that are essential for spermatogenesis.

Male infertility in Sertoli cell-only syndrome: An investigation of autosomal gene defects.

OBJECTIVES: To detect autosomal genetic defects and to determine candidate genes in Sertoli cell-only syndrome infertile men. METHODS: Single-nucleotide polymorphism + comparative genomic hybridization microarray technology was carried out on 39 Sertoli cell-only syndrome infertile patients in the present study. Array comparative genomic hybridization compares the patient's genome against a reference genome, and identifies uncover deletions, amplifications and loss of heterozygosity. RESULTS: A link between defective spermatogenesis genes and infertility was examined, and amplifications and deletions in several genes were detected, including homeobox gene; synaptonemal complex element protein 1; collagen, type I, alpha 1; imprinted maternally expressed transcript; and potassium voltage-gated channel subfamily Q member 1. CONCLUSIONS: The present data suggest that several genes can play an important role in spermatogenesis and progression of Sertoli cell-only syndrome.

Identification of Premeiotic, Meiotic, and Postmeiotic Cells in Testicular Biopsies Without Sperm from Sertoli Cell-Only Syndrome Patients.

Sertoli cell-only syndrome (SCOS) affects about 26.3⁻57.8% of azoospermic men, with their seminiferous tubules containing only Sertoli cells. Recently, it was reported that testicular biopsies from nonobstructive azoospermic (NOA) patients contained germ cells, and that sperm could be found in the tubules of 20% of SCOS patients using testicular sperm extraction technology. Since the patients without sperm in their testicular biopsies do not have therapy to help them to father a biological child, in vitro maturation of spermatogonial stem cells (SSCs) isolated from their testis is a new approach for possible future infertility treatment. Recently, the induction of human and mice SSCs proliferation and differentiation was demonstrated using different culture systems. Our group reported the induction of spermatogonial cell proliferation and differentiation to meiotic and postmeiotic stages in mice, rhesus monkeys, and prepubertal boys with cancer using 3D agar and methylcellulose (MCS) culture systems. The aim of the study was to identify the type of spermatogenic cells present in biopsies without sperm from SCOS patients, and to examine the possibility of inducing spermatogenesis from isolated spermatogonial cells of these biopsies in vitro using 3D MCS. We used nine biopsies without sperm from SCOS patients, and the presence of spermatogenic markers was evaluated by PCR and specific immunofluorescence staining analyses. Isolated testicular cells were cultured in MCS in the presence of StemPro enriched media with different growth factors and the development of colonies/clusters was examined microscopically. We examined the presence of cells from the different stages of spermatogenesis before and after culture in MCS for 3⁻7 weeks. Our results indicated that these biopsies showed the presence of premeiotic markers (two to seven markers/biopsy), meiotic markers (of nine biopsies, cAMP responsive element modulator-1 (CREM-1) was detected in five, lactate dehydrogenase (LDH) in five, and BOULE in three) and postmeiotic markers (protamine was detected in six biopsies and acrosin in three). In addition, we were able to induce the development of meiotic and/or postmeiotic stages from spermatogonial cells isolated from three biopsies. Thus, our study shows for the first time the presence of meiotic and/or postmeiotic cells in biopsies without the sperm of SCOS patients. Isolated cells from some of these biopsies could be induced to meiotic and/or postmeiotic stages under in vitro culture conditions.

Study of trinucleotide expansions and expression of androgen receptor in infertile men with abnormal spermogram referred to Royan institute.

Androgen receptor (AR) mediates androgen activities such as the growth of accessory sex organs, and initiation and promotion of spermatogenesis. There are two trinucleotide polymorphisms (CAG and GGN repeats) in the first exon of AR gene that their association with infertility is still controversial. The variants of both polymorphic repeats were investigated by PCR-Sequencing in 220 infertile men (80 azoospermic, 60 oligospermic and 80 asthenospermic) and 80 healthy fertile controls. AR Expression level was quantified by RT-qPCR on 30 patients (20 patients with nonobstructive azoospermia (NOA) and 10 obstructive azoospermia patients as controls). Our results demonstrated that the medians of CAG and GGN repeats length in infertile group were significantly higher than fertile men (p < 0.05). AR expression results showed a significant increase in SCOS group compared to control (p < 0.05). Long stretches of tandem repeats of AR gene may negatively affect the function of the gene and consequently lead to male infertility. In patients with SCOS, AR expression increases because of the lack of germ cells. Therefore, with increasing AR expression, the probability of SCOS occurrence is also increased. It can be concluded that increasing AR expression in testes tissue decreases the probability of sperm presence.

Testicular sperm extraction after laparoscopic orchiectomy for bilateral postpubertal intra-abdominal cryptorchidism: What chance of sperm retrieval?

Infertility occurs in up to 54% of men with bilateral undescended testes. Orchiectomy is considered the best therapeutic approach, especially when cryptorchidism is diagnosed in adulthood, due to a high risk of malignancy. A 33-year-old man was referred with a clinical presentation of empty scrotum and an ultrasonography and magnetic resonance imaging evaluation of intra-abdominal bilateral cryptorchidism. Follicle-stimulating hormone was 23.20 IU/L, luteinising hormone was 14.10 IU/L, total testosterone was 12.1 nmol/L, and 17-beta-oestradiol was 0.16 nmol/L. Semen analysis showed absolute azoospermia. Tumour marker levels were in the normal range. Testicular volume was 4.0 ml for right testis and 4.6 ml for left testis. The patient underwent a laparoscopy bilateral orchiectomy and subsequently a testicular sperm extraction (TESE), in the purpose to finding mature spermatozoa. The biological examination revealed the presence of immature sperm cells, not efficient for a cryopreservation. The histologic analyses show a pattern of Sertoli cell-only syndrome and maturation arrest. TESE might be a good option for patients with absolute azoospermia and cryptorchidism, especially if bilateral. The procedure, performed after orchiectomy, is safe and does not have any impact on patient's health, although it is important to clarify the very low potential of sperm recovery.

Histological alterations in Leydig cells and macrophages in azoospermic men.

The study aimed to compare the histological features of Leydig cells and macrophages in the testicular interstitium of obstructive versus nonobstructive azoospermia. Thirty-nine azoospermic men undergoing testicular sperm extraction during intracytoplasmic sperm injection were allocated into obstructive azoospermia group (GI) and nonobstructive azoospermia group (GII) which was subdivided into Sertoli cell-only syndrome (GIIA), germ cell arrest (GIIB) and hypospermatogenesis (GIIC) subgroups. Serum LH, FSH and testosterone levels were measured. Ultrastructural changes and the mean number of CD68-positive cells were estimated in the different groups. In GIIA, Leydig cells' processes came in contact with macrophages and showed smooth endoplasmic reticulum dilatation. In GIIB, Leydig cells showed apoptotic changes. Macrophages were commonly encountered in their vicinity demonstrating large number of lysosomes. In GIIC, Leydig cells showed euchromatic nuclei. Macrophages showed expulsion of their lysosomal contents in the interstitium surrounded by apoptotic bodies. The mean count of total CD68-positive macrophages was higher in cases of obstructive azoospermia with nonsignificant differences compared to nonobstructive azoospermia groups. Significant increase in FSH level was detected in GIIA compared to GI. It is concluded that structural interactions might take place between Leydig cells and macrophages in the interstitial tissue of azoospermic men.

Testicular histology may predict the successful sperm retrieval in patients with non-obstructive azoospermia undergoing conventional TESE: a diagnostic accuracy study.

PURPOSE: The present study sought to determine the diagnostic accuracy of FSH level, testicular volume, and testicular histology in predicting the successful sperm retrieval (SSR) in a large cohort of patients with non-obstructive azoospermia undergoing conventional testicular sperm extraction (TESE). METHODS: We retrospectively evaluated 356 patients with non-obstructive azoospermia between June 2004 and July 2009. Binary logistic regression was used to evaluate the diagnostic accuracy of our predicting model, identifying sperm retrieval rate as binary dependent variable. The predictive accuracy of all variables individually evaluated was quantified with area under curve (AUC) estimates derived from receiver operating characteristic (ROC) curve. RESULTS: The mean patients' age was 36.8 years. Testicular sperm were retrieved in 158 out of 356 patients (44.3 %). Histological diagnosis of Sertoli cell only syndrome (SCO) was obtained in 216 patients (60.6 %), while 55 patients (15.4 %) had maturation arrest (MA) and 85 (23.8 %) had hypospermatogenesis (HYPO). The binary logistic regression model was statistically significant (χ 2 = 96.792, p < 0.0001) and correctly classified 72.8 % of cases with 46.8 % sensitivity and 93.4 % specificity, positive predictive value (PPV) 85.06 %, negative predictive value (NPV) 68.7 %, +likelihood ratio (LR) 7.13, and -LR 0.57. Only testicular histology was significant to the model, while FSH and testicular volume were not. Sperm retrieval rate (SRR) was significantly higher in patients with HYPO compared to patients with SCO or MA (88.2 vs 30.5 and 30.9 %, respectively, p < 0.0001) CONCLUSIONS: This study demonstrates that including testicular histology in a model for predicting sperm retrieval increases its diagnostic accuracy. As histology is not available prior to TESE, this model applies only to patients with previous testicular surgery.

Microdissection TESE is superior to conventional TESE in patients with nonobstructive azoospermia caused by Y chromosome microdeletions.

Nonobstructive azoospermia is caused in up to 10% by microdeletions of the Y chromosome in the azoospermia factor (AZF) region, which is divided into three nonoverlapping areas (AZFa, AZFb and AZFc). In 25 male patients with AZF microdeletions, the results of two different techniques for surgical sperm retrieval (SR), conventional multilocular TESE and microdissection TESE, were studied retrospectively over a period of 19 years. Conventional multilocular TESE was carried out in 11 patients and microdissection TESE in 14 patients. Successful SR was possible only in patients with isolated AZFc microdeletions, so only the 20 patients with AZFc microdeletions alone were taken into account for the comparison of the both operative techniques. The sperm detection rate for conventional multilocular TESE was 25%, the sperm detection for microdissection TESE was significantly higher with 67%. In all patients, a histological examination of the testicular tissue was carried out, which showed a mixed picture, but Sertoli-cell-only syndrome in most cases. FSH was no prognostic marker for successful SR. In two of six couples performing an intracytoplasmic sperm injection until now, a pregnancy occurred.

The poly(A)-binding protein genes, EPAB, PABPC1, and PABPC3 are differentially expressed in infertile men with non-obstructive azoospermia.

PURPOSE: Azoospermia is one of the major causes of male infertility and is basically classified into obstructive (OA) and non-obstructive azoospermia (NOA). The molecular background of NOA still largely remains elusive. It has been shown that the poly(A)-binding proteins (PABPs) essentially play critical roles in stabilization and translational control of the mRNAs during spermatogenesis. METHODS: In the present study, we aim to evaluate expression levels of the PABP genes, EPAB, PABPC1, and PABPC3, in the testicular biopsy samples and in the isolated spermatocyte (SC) and round spermatid (RS) fractions obtained from men with various types of NOA including hypospermatogenesis (hyposperm), RS arrest, SC arrest, and Sertoli cell-only syndrome (SCO). RESULTS: In the testicular biopsy samples, both PABPC1 and PABPC3 mRNA expressions were gradually decreased from hyposperm to SCO groups (P < 0.05), whereas there was no remarkable difference for the EPAB expression among groups. The expression levels of cytoplasmically localized PABPC1 and PABPC3 proteins dramatically reduced from hyposperm to SCO groups (P < 0.05). In the isolated SC and RS fractions, the EPAB, PABPC1, and PABPC3 mRNA expressions were gradually decreased from hyposperm to SC arrest groups (P < 0.05). Similarly, both PABPC1 and PABPC3 proteins were expressed at higher levels in the SC and RS fractions from hyposperm group when compared to the SC and RS fractions from either RS arrest or SC arrest group (P < 0.05). CONCLUSION: Our findings suggest that observed significant alterations in the PABPs expression may have an implication for development of different NOA forms.

PRPS2 Expression Correlates with Sertoli-Cell Only Syndrome and Inhibits the Apoptosis of TM4 Sertoli Cells.

PURPOSE: Sertoli-cell only syndrome is one of the reasons for male infertility but its pathogenesis remains unclear. PRPS2, a subset of PRS, is reported to be a potential protein associated with Sertoli-cell only syndrome. In this study we further investigated the correlation between PRPS2 and Sertoli-cell only syndrome, and evaluated the effect of PRPS2 expression on apoptosis of TM4 Sertoli cells. MATERIALS AND METHODS: PRPS2 expression was detected in patients with Sertoli-cell only syndrome and normal spermatogenesis, and in Sertoli-cell only syndrome mouse models by immunohistochemistry, quantitative reverse transcription-polymerase chain reaction and Western blot. PRPS2 expression in TM4 Sertoli cells was then down-regulated and up-regulated by lentivirus vectors. The effect of PRPS2 expression on cell apoptosis and cell cycle transition was evaluated by flow cytometry. RESULTS: PRPS2 expression in patients with Sertoli-cell only syndrome was significantly greater than in those with normal spermatogenesis. A significant increase in PRPS2 expression was observed in Sertoli-cell only syndrome mouse models. PRPS2 over expression significantly inhibited cell apoptosis and promoted cell cycle transition in TM4 Sertoli cells. However, PRPS2 down-regulation showed a reverse effect. Moreover, results revealed that PRPS2 over expression inhibited cell apoptosis via the p53/Bcl-2/caspase-9/caspase-3/caspase-6/caspase-7 signaling pathway. CONCLUSIONS: PRPS2 expression correlates with Sertoli-cell only syndrome and inhibits the apoptosis of TM4 Sertoli cells via the p53/Bcl-2/caspases signaling pathway.