Gonadotoropin actions on spermatogenesis and hormonal therapies for spermatogenic disorders [Review]

The exposure to nandrolone changed the expression of genes associated with sexual differentiation and disrupted the levels of hormones in the hypothalamic-pituitary-gonadal (HPG) axis, ultimately inducing male differentiation in zebrafish (Danio rerio)

Various anabolic androgenic steroids (AAS) are frequently detected in aquatic environments, yet the potential ecotoxicological impacts of their increased load have not received adequate attention. This study investigates the effects of exposure to the androgen nandrolone on sex differentiation, gonadal development, and the expression of hormones, enzymes, and proteins related to the hypothalamic-pituitary-gonadal (HPG) axis in zebrafish. The results indicate that exposure to nandrolone at 60 days post-fertilization promotes the maturation of spermatogonia, inhibits the development of oocytes, and induces their apoptosis. Additionally, there were dose-dependent changes in male differentiation and hormone levels within the HPG axis: in the high-dose group (5 μg/L), males constituted 73 % of the population, and levels of E2 hormones in gonadal tissues decreased by 33 %, while T hormone levels increased by 55 %. Furthermore, the expression of genes essential for ovarian differentiation were downregulated, whereas the expression of testicular differentiation-related genes were upregulated. The molecular docking results show that the drug can form hydrogen bonds with key proteins, which have high affinity, and are more likely to cause conformational changes in the proteins, thereby altering their activity. KEGG analysis suggests that the MAPK signaling pathway is likely the target pathway through which nandrolone exposure induces reproductive toxicity.

Transcriptomics-based analysis of neurotoxic and reproductive effects in turbot (Scophthalmus maximus) after exposure to tris (2-chloroethyl) phosphate (TCEP)

BACKGROUND

Tris (2-chloroethyl) phosphate (TCEP), a widely used flame retardant, is widespread in the environment and potentially harmful to organisms. However, the specific mechanisms of TCEP-induced neurological and reproductive toxicity in fish are largely unknown. Turbot (Scophthalmus maximus) is cultivated on a large scale, and the emergence of pollutants with endocrine disrupting effects seriously affects its economic benefits. This study aimed to investigate the toxic effects of TCEP on turbot by integrating physio-biochemical and transcriptomic analyses.

RESULTS

TCEP exposure induced severe neuroendocrine disrupting effects in turbot. Firstly, the hormone levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E2), and 11-ketotestosterone (11-KT) were significantly decreased under prolonged TCEP stress, which may have a negative impact on normal reproductive function. We identified and summarized representative differentially expressed genes (DEGs) and their functions, such as endocrine system and oxidative stress. Pathway enrichment showed that the toxicological characteristics of TCEP on turbot were neuroendocrine regulation disorders, including oxidative phosphorylation, apoptosis, steroid biosynthesis, GnRH signaling pathway and so on. Weighted gene co-expression network analysis (WGCNA) also revealed key genes involved in these pathways. Among these genes, those encoding the components of the electron transport chain presented an initial increase in expression followed by a decrease, indicating that TCEP stress might affect mitochondrial function and lead to cell damage. This finding was also supported by the upregulation of apoptosis-related gene expression. Moreover, acute exposure to TCEP regulated MAPK-mediated transduction and regulation of GnRH signaling, thereby altering the expression of hypothalamic-pituitary-gonadal (HPG) axis-related genes.

CONCLUSIONS

These findings revealed the endocrine disrupting effects of TCEP on turbot and identified biomarkers related to reproductive toxicity, providing early warning for the monitoring of healthy aquaculture.

The role of luteinizing hormone activity in spermatogenesis: from physiology to clinical practice

The production of spermatozoa, a process known as spermatogenesis, is primarily controlled by follicle-stimulating hormone (FSH) and luteinizing hormone (LH)-driven testosterone. LH acts on the Leydig cells, stimulating steroid production, predominantly testosterone, and activating critical inter-related spermatogenesis regulatory pathways. Despite evidence that exogenous gonadotropins containing LH activity can effectively restore spermatogenesis in males with hypogonadotropic hypogonadism, the use of these drugs to treat other forms of male infertility is the subject of an ongoing debate. In this review, we delve into the molecular properties and functions of LH activity in spermatogenesis regulation and explore available preparations for therapeutic use. We also examine the evidence regarding the effectiveness of LH-containing drugs in treating specific male infertility conditions and identify the main areas for future research. Our review highlights the critical role of LH in spermatogenesis and emphasizes the potential of LH-containing drugs in treating male infertility. However, further research is required to completely elucidate the mechanisms underlying the effects of LH activity on sperm production and to establish the most effective dosages and treatment durations.

Does the FNA sperm retrieval failure prediction model work well for current NOA individuals undertaking risk screening before the operation? Model validation, high-risk population identification and potential alternative sperm retrieval exploration

BACKGROUND

Non-obstructive azoospermia (NOA), the severe type of male infertility. The objective of this study was to evaluate the predictive accuracy of a prediction model of sperm retrieval failure with fine needle aspiration (FNA).

METHODS

This study involved 769 NOA patients (dataset 1) undertaking FNA and 140 NOA patients undertaking mTESE (dataset 2). The previous model was validated and then reconstructed for more potential risk factors and better accuracy in dataset 1. The reconstructed model was evaluated in NOA patients with different new variables. The outcomes of the micro- testicular sperm extraction (mTESE) were compared with the predicted outcomes of FNA to evaluate its potential as an alternative surgical sperm retrieval (SSR) technique.

RESULTS

307 (39.92%) males experienced sperm retrieval failure in FNA while 92 (65.7%) males experienced sperm retrieval failure in mTESE. The refined model has 80% overall agreement (n = 616). The reconstructed model had an AUROC of 0.876 (95% CI: 0.850-0.921). The mTESE has significantly higher success rate (34.29%) than the predicted success rate of FNA (5.71%).

CONCLUSIONS

Previous model shows good consistency. mTESE can be an alternative SSR method for NOA patients with a high predicted risk of sperm retrieval failure with FNA.

Clinical factors impacting microdissection testicular sperm extraction success in hypogonadal men with nonobstructive azoospermia

OBJECTIVE

To explore factors influencing microdissection testicular sperm extraction (micro-TESE) success in hypogonadal men with nonobstructive azoospermia (NOA).

DESIGN

A cohort study.

SETTING

University-affiliated male reproductive health center.

PATIENT(S)

A total of 616 consecutive patients with NOA and hypogonadism (total testosterone [T] levels <350 ng/dL) underwent micro-TESE between 2014 and 2021. All patients had no prior sperm retrieval (SR) history.

INTERVENTION(S)

Patients aged 23-55 years underwent comprehensive clinical, laboratory, and histopathological diagnostic evaluation for NOA and were further categorized into two cohorts on the basis of pre-SR hormonal stimulation.

MAIN OUTCOME MEASURE(S)

A multivariable logistic regression analysis explored the associations between patient variables and micro-TESE success, defined as the presence of viable spermatozoa in extracted specimens. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were computed to assess the relationship between SR success and relevant predictors. Sperm retrieval rates were compared between patients receiving or not hormonal stimulation, and logistic regression analysis evaluated the effect of baseline follicle-stimulating hormone levels (i.e., normogonadotropic vs. hypergonadotropic classes) on SR success.

RESULT(S)

The overall micro-TESE success rate was 56.6%. Baseline follicle-stimulating hormone levels (aOR, 0.97; 95% CI, 0.94-0.99), pre-SR hormonal stimulation (aOR, 2.54; 95% CI, 1.64-3.93), presence of clinical varicocele (aOR, 0.05; 95% CI, 0.01-0.51), history of previous varicocelectomy (aOR, 2.55; 95% CI, 1.26-5.16), and testicular histopathology were independent predictors of SR success. Among hormone-pretreated patients, pre-micro-TESE T levels and delta T (an absolute increase in T levels from baseline) were associated with SR success. A pre-micro-TESE T level of 418.5 ng/dL (area under the curve value: 0.78) and a delta T of 258 ng/dL (area under the value: 0.76) distinguished patients with positive and negative SR outcomes. Subgroup analysis showed that pre-SR hormonal stimulation yielded a greater benefit for normogonadotropic patients than for those who were hypergonadotropic.

CONCLUSION(S)

This study underscores the association between clinical factors and micro-TESE success in hypogonadal men with NOA. Although causality is not established, our findings suggest that these patients may benefit from pre-SR interventions, particularly hormonal stimulation and varicocele repair.

CLINICAL TRIAL REGISTRATION NUMBER

NCT05110391.

PRSS50-mediated inhibition of MKP3/ERK signaling is crucial for meiotic progression and sperm quality

Serine protease 50 (PRSS50/TSP50) is highly expressed in spermatocytes. Our study investigated its role in testicular development and spermatogenesis. Initially, PRSS50 knockdown was observed to impair DNA synthesis in spermatocytes. To further explore this, we generated PRSS50 knockout ( Prss50 -/- ) mice ( Mus musculus), which exhibited abnormal spermatid nuclear compression and reduced male fertility. Furthermore, dysplastic seminiferous tubules and decreased sex hormones were observed in 4-week-old Prss50 -/- mice, accompanied by meiotic progression defects and increased apoptosis of spermatogenic cells. Mechanistic analysis indicated that PRSS50 deletion resulted in increased phosphorylation of extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) and elevated levels of MAP kinase phosphatase 3 (MKP3), a specific ERK antagonist, potentially accounting for testicular dysplasia in adolescent Prss50 -/- mice. Taken together, these findings suggest that PRSS50 plays an important role in testicular development and spermatogenesis, with the MKP3/ERK signaling pathway playing a significant role in this process.

The proliferation and differentiation of spermatogonial stem cells in the frist wave of spermatogenesis in rats with Trib3 gene knockout

This study explores the effects of Trib3 gene knockout on adult male rat spermatogenesis. Using CRISPR/Cas9, we knocked out the Trib3 gene in Wistar rats. Results indicate altered expression of PLZF, ID4, and c-KIT in knockout rats, suggesting impaired spermatogonial stem cell proliferation and differentiation. Histological analysis reveals reduced seminiferous tubule area and decreased spermatocyte numbers. Mating experiments demonstrate reduced offspring rates after the second self-mating in knockout rats. SYCP3, a meiosis marker, shows elevated expression in knockout rat testes at 14 days postpartum, suggesting an impact on reproductive processes. ELISA results indicate decreased testosterone, FSH, and FGF9 levels in knockout rat testicular tissues. In conclusion, Trib3 gene deletion may impede spermatogonial self-renewal and promote differentiation through the FSH-FGF9- c-KIT interaction and p38MAPK pathway, affecting reproductive capacity. These findings contribute to understanding the molecular mechanisms regulating spermatogenesis.

Endocrine health in survivors of adult-onset cancer

Long-term survivors of cancer (ie, the patient who is considered cured or for whom the disease is under long-term control and unlikely to recur) are at an increased risk of developing endocrine complications such as hypothalamic-pituitary dysfunctions, hypogonadisms, osteoporosis, or metabolic disorders, particularly when intensive tumour-directed therapies are applied. Symptom severity associated with these conditions ranges from mild and subclinical to highly detrimental, affecting individual health and quality of life. Although they are usually manageable, many of these endocrine pathologies remain underdiagnosed and untreated for years. To address this challenge, a higher degree of awareness, standardised screening tools, comprehensible treatment algorithms, and a close collaborative effort between endocrinologists and oncologists are essential to early identify patients who are at risk, and to implement appropriate treatment protocols. This Review highlights common symptoms and conditions related to endocrine disorders among survivors of adult-onset cancer, provides a summary of the currently available practice guidelines, and proposes a practical approach to diagnose affected patients among this group.

Comparative studies on the chemical composition and pharmacological effects of vinegar-processed antler glue modified from Lei Gong Pao Zhi Lun and traditional water-processed antler glue

ETHNOPHARMACOLOGICAL RELEVANCE

Antler glue is a classic medicinal to enhance sexual function in traditional Chinese medicine (TCM), which was first recorded in Shen Nong Ben Cao Jing (Shennong's Classic of the Materia Medica). Vinegar-processing is a classic method of processing traditional Chinese medicine. The method of preparing antler glue by boiling antlers in vinegar and then concentrating them is recorded in Lei Gong Pao Zhi Lun (Master Lei's Discourse on Medicinal Processing). In modern times, the typical processing method of antler glue is water extraction and concentration. However, it is not clear whether there is a difference in the effect of these two processing methods on the chemical composition and pharmacological activity of antler glue.

AIM OF THE STUDY

The Chinese Pharmacopoeia (2020) records that the processing method of antler glue is water extraction and concentration. But Lei Gong Pao Zhi Lun differs in Chinese Pharmacopoeia (2020), which records the processing method of vinegar extraction and concentration. The effect of the two processing methods on antler glue's chemical composition and pharmacological activity is unknown. So this study aimed to elucidate the difference between different processing methods on the chemical composition and the treatment effect on oligoasthenospermia of antler glue.

MATERIALS AND METHODS

So the automatic amino acid analyzer is used to determine the amino acid content of two different processing methods of antler glue. Proteomics was performed to detect the protein components of two different processing methods of antler glue and analyze them. Cyclophosphamide-induced mice models of oligoasthenospermia were used to study the different pharmacological effects of antler glue in two different processing methods. An automatic sperm analyzer observed the quantity and quality of sperm in mice epididymis. Serum sex hormone testosterone (T), luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels in mice were tested using the enzyme-linked immunosorbent assay (ELISA) kits. Hematoxylin-eosin (H&E) staining was used to analyze pathological alterations in mouse testicular tissue. The transcriptome has been used to reveal the potential mechanism of antler glue in treating oligoasthenospermia. Mitochondrial complex activity assay kits were used to assay the activity of mitochondrial respiratory chain complex I-V in mouse testicular tissue. Western blot was used to determine the expression of related proteins in mouse testicular tissue.

RESULTS

Vinegar-processing can increase the alanine, proline, and glycine content in antler glue, reduce the length of protein peptides in antler glue, and produce a variety of unique proteins. Vinegar-processed antler glue (VAG) increased sperm density, sperm survival, sperm viability, and serum sex hormone levels in oligozoospermic mice. It reversed testicular damage caused by cyclophosphamide, and the effects were differently superior to those of water-processed antler glue (WAG). In addition, transcriptomics and related experiments have shown that VAG can increase the expression of Ndufa2, Uqcr11, Cox6b1, and Atp5i genes and proteins in mouse testis, thus promoting adenosine diphosphate (ATP) synthesis by increasing the activity of mitochondrial respiratory chain complexes I, III, IV and V. By promoting the oxidative phosphorylation process to produce more ATP, VAG can achieve the therapeutic effect of oligoasthenospermia.

CONCLUSION

Vinegar-processing method can increase the content of active ingredients in antler glue. VAG increases ATP levels in the testes by promoting the process of oxidative phosphorylation to treat oligozoospermia.

Prevalence and clinical implications of biochemical hypogonadism in patients with nonobstructive azoospermia undergoing infertility evaluation

Objective

To investigate the prevalence and clinical implications of biochemical hypogonadism in infertile men with nonobstructive azoospermia (NOA).

Design

Cohort study.

Setting

University-affiliated tertiary center for male reproductive health.

Patients

767 consecutive normogonadotropic or hypergonadotropic patients with NOA undergoing infertility evaluation from 2014 to 2021.

Intervention

Patients aged 23-55 years underwent comprehensive clinical, hormonal, genetic, semen analysis, and histopathology evaluations and were classified on the basis of predefined baseline follicle-stimulating hormone (12 IU/L) and total testosterone (350 ng/dL) serum levels cutpoints into four groups: hypergonadotropic hypogonadal, hypergonadotropic eugonadal, normogonadotropic hypogonadal, and normogonadotropic eugonadal. All patients were naïve regarding previous sperm retrieval (SR) or hormonal therapy use.

Main Outcome Measures

The period prevalence of biochemical hypogonadism, defined as testosterone levels of <350 ng/dL, and the distribution of patients per group were computed. The associations between hypogonadism, clinical factors, and SR success were evaluated using multivariable logistic regression analyses. Adjusted relative risks (aRRs) and 95% confidence intervals (CIs) were estimated to assess the association between SR and patient classification.

Results

The overall period prevalence of biochemical hypogonadism was 80.8% (95% CI 77.9%-83.4%). The prevalence of patients by group was hypergonadotropic hypogonadal (42.4%, 38.9%-45.9%), normogonadotropic hypogonadal (38.5%; 35.1%-41.9%), hypergonadotropic eugonadal (8.3%; 6.6%-10.5%), and normogonadotropic eugonadal (10.8%; 8.8%-13.2%). Reduced testicular volume and lower estradiol levels were associated with an increased likelihood of hypogonadism. Paternal age was also an independent predictor, with higher age linked to an increased likelihood of hypogonadism. Hypogonadism was less likely in patients with germ cell maturation arrest and more likely in those with Sertoli cell-only. Patients with hypergonadotropic hypogonadism had lower SR success than normogonadotropic eugonadal counterparts (aRR 0.611; 95% CI 0.398-0.855). In the subset of hypogonadal men, hypergonadotropic patients had lower SR success than normogonadotropic participants (aRR 0.632; 0.469-0.811).

Conclusion

The prevalence of biochemical hypogonadism among men with NOA is substantial. Hypogonadism is associated with testicular volume, estradiol levels, age, and histopathology patterns. This condition impacts SR success and emphasizes the need for improved care for men with NOA.

Alleviating 3-MCPD-induced male reproductive toxicity: Mechanistic insights and resveratrol intervention

3-Monochloropropane-1, 2-diol (3-MCPD), a food-borne contaminant, is widely regarded as the primary cause of male infertility. At present, identifying a method to improve/reduce the male reproductive toxicity caused by 3-MCPD is important. In our study, we explored the potential application of resveratrol (RSV) in mitigating the adverse effects of 3-MCPD. Using 7-week-old Sprague-Dawley (SD) rats as animal models, we investigated the impacts and underlying mechanisms of 3-MCPD and RSV on reproductive function. The administration of 3-MCPD led to significant reductions in testicular and epididymal weights, as well as disruptions in spermatogenesis and histological abnormalities. However, co-treatment with RSV and 3-MCPD mitigated these adverse effects. In vitro study, RSV exhibited the ability to reverse the decline in Leydig and Sertoli cell populations inflicted by 3-MCPD treatment. Mechanistically, RSV reduced endoplasmic reticulum stress (PARP), inflammasome activation (NLRP3), and autophagy-mediated lysosome dysfunction (p62 and LC3BII) induced by 3-MCPD. In addition, 3-MCPD treatment increased the expression level of steroidogenesis-related proteins, steroidogenic acute regulatory (StAR) and CYP11A1, but RSV normalized StAR expression. Moreover, 3-MCPD-induced pro-inflammatory responses were counteracted by RSV treatment, with the cytokine reduction and modulation of CD206 expression, a marker of macrophage activation. These findings indicate that RSV attenuates 3-MCPD-induced reproductive toxicity, highlighting its application potential as an adjuvant agent for male reproductive health.

Leydig cell metabolic disorder act as a new mechanism affecting for focal spermatogenesis in Klinefelter syndrome patients: a real world cross-sectional study base on the age

Background

Klinefelter's syndrome (KS) was once considered infertile due to congenital chromosomal abnormalities, but the presence of focal spermatozoa changed this. The key to predict and promote spermatogenesis is to find targets that regulate focal spermatogenesis.

Objective

To explore the trend of fertility changes in KS patients at different ages and identify potential therapeutic targets.

Methods

Bibliometric analysis was used to collect clinical research data on KS from the Web of Science Core Collection (WoSCC) from 1992 to 2022. A cross-sectional study was conducted on 75 KS patients who underwent microscopic testicular sperm extraction (mTESE) from 2017 to 2022 in the real world. The reproductive hormones, testicular histopathology, androgen receptors, insulin-like factor 3 (INSL3) receptors and sperm recovery rate (SRR) were analyzed.

Results

Male infertility, dysplasia, Sertoli cells, Leydig cells, testosterone and spermatogenesis were the research focuses related to KS. Luteinizing hormone (LH), testosterone, and INSL3 were evaluation indicators of Leydig cell function that fluctuate with age. Testosterone and LH peaked at ages 13-19 and 30-45, while INSL3 only peaked at ages 13-19. 27 patients (27/75) recovered sperm through mTESE and experienced SRR peaks at the ages of 20, 28, 34, and 37. The SRR of fibrosis patients was 46.15%, fatty degeneration was 7.14%, and melanosis was 40.00%. The INSL3 and androgen receptors were highly expressed and roughly balanced in focal spermatogenesis.

Conclusion

Abnormal metabolism of Leydig cells led to imbalanced expression of INSL3 and androgen receptors, which might be a potential target for spermatogenesis in KS.

Transcriptomic profiling reveals the neuroendocrine-disrupting effect and toxicity mechanism of TBBPA-DHEE exposure in zebrafish (Danio rerio) during sexual development

TBBPA bis(2-hydroxyethyl) ether (TBBPA-DHEE) pollution in the environment has raised serious public health concerns due to its potential neuroendocrine-disrupting effects. The neuroendocrine-disrupting effects of TBBPA-DHEE on marine spices, on the other hand, have received little attention. The behavioral, neuroendocrine-disrupting, and possible reproductive toxicity of TBBPA-DHEE were assessed in sexual developing zebrafish treated for 40 days by examining locomotor activity, Gonadotrophin releasing hormone (GnRH), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) levels, and quantifying gene expression. In addition, transcriptome profiling was carried out to explore the possible mechanisms. According to our findings, TBBPA-DHEE treated zebrafish showed altered locomotor activity, a potential neuroendocrine-disrupting effect via the toxic effect on the hypothalamus and pituitary gland, which is evident in decreased levels of GnRH, FSH, and LH, according to our findings. The transcriptomic profiling reveals that a total of 216 DEGs were detected (5 upregulated and 211 down-regulated). Transcriptomic analysis shows that TBBPA-DHEE exposure caused decreased transcript levels of genes (cyp11a1, ccna1, ccnb2, ccnb1, cpeb1b, wee2) involved in cell cycle oocyte meiosis, progesterone mediated oocyte maturation, and ovarian steroidogenesis, which are known reproduction-related pathways. Overall, these findings add to our understanding of the impact of TBBPA-DHEE and biomonitoring in the maritime environment.

Male infertility and gonadotropin treatment: What can we learn from real-world data?

Gonadotropin therapy to treat specific male infertility disorders associated with hypogonadotropic hypogonadism is evidence-based and effective in restoring spermatogenesis and fertility. In contrast, its use to improve fertility in men with idiopathic oligozoospermia or nonobstructive azoospermia remains controversial, despite being widely practiced. The existence of two major inter-related pathways for spermatogenesis, including FSH and intratesticular testosterone, provides a rationale for empiric hormone stimulation therapy in both eugonadal and hypogonadal males with idiopathic oligozoospermia or nonobstructive azoospermia. Real-world data (RWD) on gonadotropin stimulating for these patient subsets, mainly using human chorionic gonadotropin and follicle-stimulating hormone, accumulated gradually, showing a positive therapeutic effect in some patients, translated by increased sperm production, sperm quality, and sperm retrieval rates. Although more evidence is needed, current insights from RWD research indicate that selected male infertility patients might be managed more effectively using gonadotropin therapy, with potential gains for all parties involved.

The potential of sertoli cells (SCs) derived exosomes and its therapeutic efficacy in male reproductive disorders

In the male reproductive system, seminiferous tubules in testis are lined by a complex stratified epithelium containing two distinct populations of cells, spermatogenic cells that develop into spermatozoa, and sertoli cells (SCs) that mainly support and nourish spermatogenic cell lineage as well as exerting powerful effect on men reproductive capacity. Different varieties of proteins, hormones, exosomes and growth factors are secreted by SCs. There are different kinds of junctions found between SCs called BTB. It was elucidated that complete absence of BTB or its dysfunction leads to infertility. To promote spermatogenesis, crosstalk of SCs with spermatogenic cells plays an important role. The ability of SCs to support germ cell productivity and development is related to its various products carrying out several functions. Exosomes (EXOs) are one of the main EVs with 30-100 nm size generating from endocytic pathway. They are produced in different parts of male reproductive system including epididymis, prostate and SCs. The most prominent characteristics of SC-based exosomes is considered mutual interaction of sertoli cells with spermatogonial stem cells and Leydig cells mainly through establishment of intercellular communication. Exosomes have gotten a lot of interest because of their role in pathobiological processes and as a cell free therapy which led to developing multiple exosome isolation methods based on different principles. Transmission of nucleic acids, proteins, and growth factors via SC-based exosomes and exosomal miRNAs are proved to have potential to be valuable biomarkers in male reproductive disease. Among testicular abnormalities, non-obstructive azoospermia and testicular cancer have been more contributed with SCs performance. The identification of key proteins and miRNAs involved in the signaling pathways related with spermatogenesis, can serve as diagnostic and regenerative targets in male infertility.

Nuclear localization of human MEIOB requires its NLS in the OB domain and interaction with SPATA22

MEIOB is a vital protein in meiotic homologous recombination and plays an indispensable role in human gametogenesis. In mammals, MEIOB and its partner SPATA22 form a heterodimer, ensuring their effective localization on single-strand DNA (ssDNA) and proper synapsis processes. Mutations in human MEIOB (hMEIOB) cause human infertility attributed to the failure of its interaction with human SPATA22 (hSPATA22) and ssDNA binding. However, the detailed mechanism is still unclear. In our study, truncated or full-length hMEIOB and hSPATA22 are traced by fused expression with fluorescent proteins (i.e., copGFP or mCherry), and the live cell imaging system is used to observe the expression and localization of the proteins. When transfected alone, hMEIOB accumulates in the cytoplasm. Interestingly, a covered NLS in the OB domain of hMEIOB is identified, which can be exposed by hSPATA22 and is necessary for the nuclear localization of hMEIOB. When hSPATA22 loses its hMEIOB interacting domain or NLS, the nuclear localization of hMEIOB is aborted. Collectively, our results prove that the NLS in the OB domain of hMEIOB and interaction with hSPATA22 are required for hMEIOB nuclear localization.

The Stallion Spermatozoa: A Valuable Model to Help Understand the Interplay Between Metabolism and Redox (De)regulation in Sperm Cells

Significance: Proper functionality of the spermatozoa depends on the tight regulation of their redox status; at the same time these cells are highly energy demanding and in the energetic metabolism, principally in the electron transport chain in the mitochondria, reactive oxygen species are continuously produced, in addition to that observed in the Krebs cycle and during the β-oxidation of fatty acids. Recent Advances: In addition, in glycolysis, elimination of phosphate groups from glyceraldehyde 3-phosphate and dihydroxyacetone phosphate results in the byproducts glyoxal (G) and methylglyoxal (MG); these products are 2-oxoaldehydes. The presence of adjacent carbonyl groups makes them strong electrophiles that react with nucleophiles in proteins, lipids, and DNA, forming advanced glycation end products. Critical Issues: This mechanism is behind subfertility in diabetic patients; in the animal breeding industry, commercial extenders for stallion semen contain a supraphysiological concentration of glucose that promotes MG production, constituting a potential model of interest. Future Directions: Increasing our knowledge of sperm metabolism and its interactions with redox regulation may improve current sperm technologies in use, and shall provide new clues to understanding infertility in males. Moreover, stallion spermatozoa due to its accessibility, intense metabolism, and suitability for proteomics/metabolomic studies may constitute a suitable model for studying regulation of metabolism and interactions between metabolism and redox homeostasis. Antioxid. Redox Signal. 37, 521-537.

Efficacy and safety of letrozole or anastrozole in the treatment of male infertility with low testosterone-estradiol ratio: a meta-analysis and systematic review

BACKGROUND

Aromatase inhibitors (AIs) have been used to treat male infertility for decades. However, due to the lack of large-scale randomized controlled studies and basic research, the efficacy and safety of AIs in the treatment of male infertility remain controversial. Therefore, it is necessary to conduct an evidence-based preliminary evaluation of the existing clinical trials of AIs in the treatment of male infertility.

METHOD

A comprehensive literature search were performed in PubMed, Embase, Cochrane, CNKI, VIP, CBM, and Wanfang databases through August 2021 for all studies. We conducted a systematic review with meta-analysis of the all available studies reporting sperm conventional parameters, gonadotropin and testosterone levels, and/or the pregnancy rate.

RESULTS

A total of 10 studies involving 666 patients were included. letrozole (LE) or anastrozole (AZ) administration increased significantly sperm concentration, total sperm count, and serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T) levels and testosterone to estradiol ratio (T/E2), but E2 levels were significantly reduced compared with baseline values. Compared with the control group, which included selective estrogen receptor modulators (SEMRs) or HCG, LE or AZ did not have any significant effect on sperm concentration, motility and morphology, except that AIs had less effect on sperm motility than the control group (WMD: -2.55; 95% CI:-4.11 to-1.00; P = 0.001).

CONCLUSION

AIs may be effective in the treatment of male infertility. For male infertile patients planning assisted reproduction, discontinuation of AIs for 2-7 days prior to sperm retrieval may increase the success rate of fertilization. Further studies with larger sample sizes are needed to validate these findings. This article is protected by copyright. All rights reserved.

Review of the environmental occurrence, analytical techniques, degradation and toxicity of TBBPA and its derivatives

BFRs (brominated flame retardants) are a class of compounds that are added to or applied to polymeric materials to avoid or reduce the spread of fire. Tetrabromobisphenol A (TBBPA) is one of the known BFR used many in industries today. Due to its wide application as an additive flame retardant in commodities, TBBPA has become a common indoor contaminant. Recent researches have raised concerns about the possible hazardous effect of exposure to TBBPA and its derivatives in humans and wildlife. This review gives a thorough assessment of the literature on TBBPA and its derivatives, as well as environmental levels and human exposure. Several analytical techniques/methods have been developed for sensitive and accurate analysis of TBBPA and its derivatives in different compartments. These chemicals have been detected in practically every environmental compartment globally, making them a ubiquitous pollutant. TBBPA may be subject to adsorption, biological degradation or photolysis, photolysis after being released into the environment. Treatment of TBBPA-containing waste, as well as manufacturing and usage regulations, can limit the release of these chemicals to the environment and the health hazards associated with its exposure. Several methods have been successfully employed for the treatment of TBBPA including but not limited to adsorption, ozonation, oxidation and anaerobic degradation. Previous studies have shown that TBBPA and its derivative cause a lot of toxic effects. Diet and dust ingestion and have been identified as the main routes of TBBPA exposure in the general population, according to human exposure studies. Toddlers are more vulnerable than adults to be exposed to indoor dust through inadvertent ingestion. Furthermore, TBBP-A exposure can occur during pregnancy and through breast milk. This review will go a long way in closing up the knowledge gap on the silent and over ignored deadly effects of TBBPA and its derivatives and their attendant consequences.

Seasonal Expression of Gonadotropin Genes in the Pituitary and Testes of Male Plateau Zokor (Eospalax baileyi)

The gonadotropins, luteinizing hormone (LH) and follicle stimulating hormone (FSH), are glycoprotein hormones in the hypothalamic-pituitary-gonadal (HPG) axis and regulate mammalian reproduction. The expression of these genes in the plateau zokor (Eospalax baileyi) is poorly understood. We characterized the immunolocalization of the luteinizing hormone receptor (LHR) and follicle stimulating hormone receptor (FSHR) in the testes and evaluated the positive immunohistochemical results and the relative mRNA expression of gonadotropin genes. During the non-breeding season (September), the relative testes weight and the seminiferous tubule diameter were significantly reduced. All germ cell types were observed during the breeding season (May), whereas only spermatogonia were observed during the non-breeding season. LHR was present in the Leydig cells whereas FSHR was present in the Sertoli cells. The mean optical density was higher during the breeding season. The mRNA expression of LHβ and FSHβ was lower in the pituitary but LHR and FSHR genes expression were higher in the testes during the breeding season. These data elucidate the expression of gonadotropin genes in the HPG axis of the male plateau zokor and suggest that gonadotropins play a vital role in the regulation of seasonal breeding.

Effects of iron oxide nanoparticles as T2-MRI contrast agents on reproductive system in male mice

Iron oxide nanoparticles (IONPs)-based contrast agents are widely used for T₂-weighted magnetic resonance imaging (MRI) in clinical diagnosis, highlighting the necessity and importance to evaluate their potential systematic toxicities. Although a few previous studies have documented the toxicity concerns of IONPs to major organs, limited data are available on the potential reproductive toxicity caused by IONPs, especially when administrated via intravenous injection to mimic clinical use of MRI contrast agents. Our study aimed to determine whether exposure to IONPs would affect male reproductive system and cause other related health concerns in ICR mice. The mice were intravenously injected with different concentrations IONPs once followed by routine toxicity tests of major organs and a series of reproductive function-related analyses at different timepoints. As a result, most of the contrast agents were captured by reticuloendothelial system (RES) organs such as liver and spleen, while IONPs have not presented adverse effects on the normal function of these major organs. In contrast, although IONPs were not able to enter testis through the blood testicular barrier (BTB), and they have not obviously impaired the overall testicular function or altered the serum sex hormones levels, IONPs exposure could damage Sertoli cells in BTB especially at a relative high concentration. Moreover, IONPs administration led to a short-term reduction in the quantity and quality of sperms in a dose-dependent manner, which might be attributed to the increase of oxidative stress and apoptotic activity in epididymis. However, the semen parameters have gradually returned to the normal range within 14 days after the initial injection of IONPs. Collectively, these results demonstrated that IONPs could cause reversible damage to the reproductive system of male mice without affecting the main organs, providing new guidance for the clinical application of IONPs as T₂-MRI contrast agents.

Critical Roles of the Circadian Transcription Factor BMAL1 in Reproductive Endocrinology and Fertility

Brain and muscle aryl-hydrocarbon receptor nuclear translocator like protein1 (BMAL1), a core component of circadian oscillation, is involved in many physiological activities. Increasing evidence has demonstrated the essential role of BMAL1 in reproductive physiology. For instance, BMAL1-knockout (KO) mice were infertile, with impaired reproductive organs and gametes. Additionally, in BMAL1-KO mice, hormone secretion and signaling of hypothalamus-pituitary-gonadal (H-P-G) hormones were also disrupted, indicating that H-P-G axis was impaired in BMAL1-KO mice. Moreover, both BMAL1-KO mice and BMAL1-knockdown by small interfering RNA (siRNA) in vitro cultured steroidogenic cells showed that BMAL1 was associated with gonadal steroidogenesis and expression of related genes. Importantly, BMAL1 also participates in pathogenesis of human reproductive diseases. In this review, we elaborate on the impaired reproduction of BMAL1-KO mice including the reproductive organs, reproductive endocrine hormones, and reproductive processes, highlighting the vital role of BMAL1 in fertility and reproductive endocrinology.

Impact of seminal and serum zinc on semen quality and hormonal status: A population-based cohort study of Russian young men

BACKGROUND

Trace elements are important factors in human reproductive health. Among them, special attention is paid to zinc, which is an essential trace element and is necessary for the normal functioning of the male reproductive system and the process of spermatogenesis. The aim of the study was to investigate the association between seminal and serum zinc concentrations and semen quality and reproductive hormone levels in population of Russian young men.

METHODS

The study population consisted of 626 young Russian men (median age 22.5 years), recruited from the general population, regardless of their fertility status. Each participant provided semen and blood sample, information about his lifestyle and ethnicity. Semen quality (sperm concentration, motility and morphology), reproductive hormone levels (testosterone, estradiol, LH, FSH and inhibin B), and serum and seminal zinc concentrations were evaluated. The semen samples were analyzed according to the WHO laboratory manual (WHO, 2010). Serum hormones were measured by enzyme immunoassay, zinc concentrations were determined using spectrophotometry and direct colorimetry without deproteinization.

RESULTS

Zinc was present in the seminal plasma in a significantly higher concentration than in the blood serum (median serum Zn concentration was 23.6 μmol/L vs seminal Zn concentration 1571.8 μmol/L). The seminal zinc concentration was positively related to the total sperm count, sperm concentration, progressive motility and normal morphology (Spearman's test: 0.221; 0.286; 0.269; 0.183, respectively, p < 0.001), while the serum Zn concentration was negatively related to serum testosterone and estradiol levels (r = -0.249 and r = -0.096, respectively, p < 0.001-0.05). It was found that the seminal Zn content in men with normal semen quality was higher compared to men with lowered semen quality (means: 6.37 and 5.03 μmol/ejaculate, respectively, p < 0.001). Similarly, the semen volume, total sperm count, sperm concentration, progressive motility, normal morphology and the serum testosterone level in men with the seminal Zn deficiency were lower than in men with the normal seminal Zn content.

CONCLUSION

Based on the results of our population-based study, seminal Zn levels were closely associated with semen parameters in young men, so Zn deficiency may be an important risk factor for lowered semen quality. Seminal Zn determinations should be considered as a useful tool in addition to other parameters in assessing male fertility.

Leydig Cells in Patients with Non-Obstructive Azoospermia: Do They Really Proliferate?

Background: Non-obstructive azoospermia (NOA) is a form of male infertility caused by disorders of the testicular parenchyma and impaired spermatogenesis. This study aimed to investigate the nature of Leydig cell changes in patients with NOA, especially whether their actual proliferation occurred. Methods: 48 testicular biopsies from infertile patients with NOA and 24 testicular biopsies originating from azoospermic patients suffering from obstructive azoospermia (OA) were included in the study. Leydig cells and their possible proliferative activity were analysed by immunohistochemistry and morphometry (stereology). Results: Unlike in the OA group, Leydig cells in NOA patients were sometimes organised into larger clusters and displayed an abundant cytoplasm/hypertrophy. Moreover, significant fibrosis of the interstitial compartment was demonstrated in some NOA samples, often accompanied by inflammatory cells. Stereological analysis showed no increase/proliferation of Leydig cells; on the contrary, these cells decreased in number in the NOA group. Conclusions: The decrease in the number of Leydig cells can be explained by previous inflammatory changes within the testicular interstitium and consequent interstitial fibrosis. The interstitial fibrosis might have a deteriorating effect on Leydig cells.

Different expression of LHR, PRLR, GH and IGF1 during testicular development of yak

Luteinizing hormone receptor (LHR), prolactin receptor (PRLR), growth hormone (GH) and insulin-like growth factor 1 (IGF1) have been shown to be key regulators of germ cell development. However, the role of LHR, PRLR, GH and IGF1 in the development of yak testis remains unclear. In this study, we aimed to describe and compare gene expression and protein localization of LHR, PRLR, GH and IGF1 in the development of yak testes. Testes were collected from 6, 24, 36 and 72 months yak, and the kidney, liver, testicular, lung, skeletal muscle, heart and spleen tissues were collected from 36 months yak. The quantitative real-time PCR (qRT-PCR) results showed that the expression of these four genes was widely expressed in kidney, liver, testicular, lung, skeletal muscle, heart and spleen, while the LHR and PRLR were highly expressed in the kidney, skeletal muscle and testis, and higher levels of GH and IGF were expressed in spleen and testis. Moreover, the mRNA expression of these genes in adults was higher than in pre-pubertal yak. In the testis, the LHR-, PRLR-, GH- and IGF1-positive signals were detected in the Leydig cells of the 6 months, while the intense positive signals were discovered in Leydig cells, spermatogonia and spermatocytes of the 36 and 72 months. Thus, LHR, PRLR, GH and IGF1 may be involved in the development of spermatids and spermatocytes, and in the regulation of spermatogonia proliferation and Leydig cell function.

The role of StAR2 gene in testicular differentiation and spermatogenesis in Nile tilapia (Oreochromis niloticus)

Sex steroids play critical roles in sex differentiation and gonadal development in teleosts. Steroidogenic acute regulatory protein (StAR), transporting cholesterol (the substrate for steroidogenesis) from the outer mitochondrial membrane to the inner membrane, is the first rate-limiting factor of steroidogenesis. Interestingly, two StAR genes (named as StAR1 and StAR2) have been isolated from non-mammalian vertebrates. To characterize the functions of the novel StAR2 gene in the gonadal differentiation and fertility, we generated a StAR2 homozygous mutant line in Nile tilapia (Oreochromis niloticus). StAR2 gene knockout in male tilapia impeded meiotic initiation, associate with the down-regulation of meiosis related gene expressions of vasa, sycp3 and dazl at 90 days after hatching (dah). Meanwhile, cyp11b2 expression and serum 11-KT production significantly declined in StAR2^-/- XY fish at 90 dah. From 120-300 dah, spermatogenesis gradually recovered, and so did the expressions of vasa, sycp3 and dazl in StAR2^-/- XY fish testes. However, seminiferous lobules arranged disorderly in StAR2^-/- XY fish testes at 300 dah. The number of Leydig cells and expressions of downstream steroidogenesis enzymes including cyp11a1, 3β-HSD-I, 3β-HSD-II, cyp17a1 and cyp17a2 decreased in StAR2^-/- XY fish testes at 300 dah. Serum testosterone and 11-KT levels were significantly lower in StAR2^-/- XY fish than that of their control counterparts. Furthermore, significantly elevated ar, fsh and lh expressions in StAR2-deficient XY fish testes and pituitaries were found when compared with the control XY fish. Testes degeneration and spermatogenic cell apoptosis were observed, while no sperm were squeezed out in StAR2^-/- XY fish testes at 540 dah. Taken together, our results suggest that StAR2 has a role in testicular development, spermatogenesis and spermiation by regulating androgen production in tilapia, but may not be essential and could be compensated.

Potential of testis-derived circular RNAs in seminal plasma to predict the outcome of microdissection testicular sperm extraction in patients with idiopathic non-obstructive azoospermia

STUDY QUESTION

Do testis-derived circular RNAs (circRNAs) in seminal plasma have potential as biomarkers to predict the outcome of microdissection testicular sperm extraction (micro-TESE) in patients with idiopathic non-obstructive azoospermia (NOA)?

SUMMARY ANSWER

Testis-derived circRNAs in the seminal plasma can indeed be used for predicting the outcome of micro-TESE in patients with idiopathic NOA.

WHAT IS KNOWN ALREADY

Micro-TESE is an effective method to obtain sperm samples from patients with idiopathic NOA. However, its success rate is only 40-50% in such patients.

STUDY DESIGN, SIZE, DURATION

Six idiopathic NOA patients with different micro-TESE results were included as the discovery cohort. Their testicular tissues were used for extracting and sequencing circRNAs. Five circRNAs with the most significantly different expression levels were selected for further verification.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Fifty-two patients with idiopathic NOA were included as the validation cohort. Preoperative seminal plasma samples of 52 patients with idiopathic NOA and 25 intraoperative testicular tissues were collected and divided into 'success' and 'failure' groups according to the results of micro-TESE. Quantitative real-time polymerase chain reaction was performed to verify differences in the expression levels of the selected circRNAs between the two groups in the testicular tissues and seminal plasma.

MAIN RESULTS AND THE ROLE OF CHANCE

Whether at the seminal plasma or testicular tissue level, the differences in the expression levels of the three circRNAs (hsa_circ_0000277, hsa_circ_0060394 and hsa_circ_0007773) between the success and failure groups were consistent with the sequencing results. A diagnostic receiver operating curve (ROC) analysis of the AUC indicated excellent diagnostic performance of these circRNAs in seminal plasma in predicting the outcome of micro-TESE (AUC values: 0.920, 0.928 and 0.891, respectively). On the basis of least absolute shrinkage and selection operator (LASSO) logistic regression, the three circRNAs were combined to construct a new prediction model. The diagnostic ROC curve analysis of the model showed an AUC value of 0.958. The expression levels of these circRNAs in seminal plasma using three normospermic volunteer samples remained stable after 48 h at room temperature.

LARGE SCALE DATA

NA.

LIMITATIONS, REASONS FOR CAUTION

This was a single-center retrospective study with relatively few cases. The functions of these circRNAs, as well as their relationship with spermatogenesis, have not yet been established.

WIDER IMPLICATIONS OF THE FINDINGS

Testis-derived circRNAs in seminal plasma can reflect the microenvironment of the testis and can be used as reliable biomarkers to screen patients with idiopathic NOA who might be suitable for micro-TESE.

STUDY FUNDING/COMPETING INTEREST(S)

This article was funded by the National Natural Science Foundation of China (Grant no. 81871151). There were no competing interests.

The initial maturation status of marmoset testicular tissues has an impact on germ cell maintenance and somatic cell response in tissue fragment culture

Successful in vitro spermatogenesis was reported using immature mouse testicular tissues in a fragment culture approach, raising hopes that this method could also be applied for fertility preservation in humans. Although maintaining immature human testicular tissue fragments in culture is feasible for an extended period, it remains unknown whether germ cell survival and the somatic cell response depend on the differentiation status of tissue. Employing the marmoset monkey (Callithrix jacchus), we aimed to assess whether the maturation status of prepubertal and peri-/pubertal testicular tissues influence the outcome of testis fragment culture. Testicular tissue fragments from 4- and 8-month-old (n = 3, each) marmosets were cultured and evaluated after 0, 7, 14, 28 and 42 days. Immunohistochemistry was performed for identification and quantification of germ cells (melanoma-associated antigen 4) and Sertoli cell maturation status (anti-Müllerian hormone: AMH). During testis fragment culture, spermatogonial numbers were significantly reduced (P < 0.05) in the 4- but not 8-month-old monkeys, at Day 0 versus Day 42 of culture. Moreover, while Sertoli cells from 4-month-old monkeys maintained an immature phenotype (i.e. AMH expression) during culture, AMH expression was regained in two of the 8-month-old monkeys. Interestingly, progression of differentiation to later meiotic stage was solely observed in one 8-month-old marmoset, which was at an intermediate state regarding germ cell content, with gonocytes as well as spermatocytes present, as well as Sertoli cell maturation status. Although species-specific differences might influence the outcome of testis fragment experiments in vitro, our study demonstrated that the developmental status of the testicular tissues needs to be considered as it seems to be decisive for germ cell maintenance, somatic cell response and possibly the differentiation potential.

Differential Diagnosis of Azoospermia in Men with Infertility

The differential diagnosis between obstructive and nonobstructive azoospermia is the first step in the clinical management of azoospermic patients with infertility. It includes a detailed medical history and physical examination, semen analysis, hormonal assessment, genetic tests, and imaging studies. A testicular biopsy is reserved for the cases of doubt, mainly in patients whose history, physical examination, and endocrine analysis are inconclusive. The latter should be combined with sperm extraction for possible sperm cryopreservation. We present a detailed analysis on how to make the azoospermia differential diagnosis and discuss three clinical cases where the differential diagnosis was challenging. A coordinated effort involving reproductive urologists/andrologists, geneticists, pathologists, and embryologists will offer the best diagnostic path for men with azoospermia.

Seminal exosomes - An important biological marker for various disorders and syndrome in human reproduction

BACKGROUND

Exosomes are nano-sized membrane vesicles, secreted by different types of cells into the body's biological fluids. They are found in abundance in semen as compared to other fluids. Exosomes contain a cargo of lipid molecules, proteins, phospholipids, cholesterol, mRNAs, and miRNAs. Each molecule of seminal exosomes (SE) has a potential role in male reproduction for childbirth. Many potential candidates are available within the seminal exosomes that can be used as diagnostic markers for various diseases or syndromes associated with male reproduction. Also these seminal exospmes play a major role in female reproductive tract for effective fertilization.

AIM

The aim of this review is to focus on the advancement of human seminal exosomal research and its various properties.

METHODS

We used many databases like Scopus, Google scholar, NCBI-NLM and other sources to filter the articles of interest published in exosomes. We used phrases like "Exosomes in human semen", "Composition of exosomes in human semen" and other relevant words to filter the best articles.

RESULTS

Seminal exosomes play a major role in sperm functions like cell-to-cell communication, motility of the sperm cells, maintaining survival capacity for the sperm in the female reproductive tract and spermatogenesis. Also, seminal exosomes are used as a carrier for many regulatory elements using small RNA molecules. miRNAs of the seminal exosomes can be used as a diagnostic marker for prostate cancer instead of prostate specific antigen (PSA). Epididymosomes can be used as a biomarker for reproductive diseases and male infertility.

CONCLUSION

Seminal exosomes could be used as biological markers for various reproductive disorders, male infertility diagnosis, and it can be used in anti-retroviral research for the identification of novel therapeutics for HIV-1 infection and transmission.

Immunization with oral KISS1 DNA vaccine inhibits testicular Leydig cell proliferation mainly via the hypothalamic-pituitary-testicular axis and apoptosis-related genes in goats

This study aimed to analyze the effect and mechanism of immunization of oral KISS1 DNA vaccine on the proliferation of goat testicular Leydig cells. Ten 8-week-old male goats were randomly divided into KISS1 DNA vaccine and control groups for immunization (five goats each group). These goats were sacrificed at 8 weeks after primary immunization, and the tissue samples of hypothalamus, pituitary, and testis and Leydig cell samples were collected for RT-PCR and CCK8 assay. Immunization with the oral KISS1 DNA vaccine effectively inhibited the proliferation of Leydig cells, the expression of hypothalamus KISS1, GPR54, and GnRH mRNA, pituitary GnRHR and LH mRNA, testicular LHR mRNA, and apoptosis-inhibitory gene Bcl-2 mRNA in Leydig cells. By contrast, the immunization enhanced the mRNA expression of apoptosis-promoting gene Bax and Clusterin in Leydig cells. These findings indicate that immunization with the oral KISS1 DNA vaccine can inhibit the proliferation of goat testicular Leydig cells mainly via the hypothalamic-pituitary-testicular axis and apoptosis-related genes.

Stimulant-Induced Pituitary Failure and Reversible Azoospermia

Attention-deficit hyperactivity disorder (ADHD) is a commonly diagnosed disorder that is managed with stimulant medications, which function by increasing the levels of dopamine in the brain. Excess dopamine has been known to affect several body systems, including the endocrine system. This case presents male factor infertility caused by a negative interaction between excess dopamine and the endocrine system, inducing pituitary failure, which led to azoospermia. The patient and her partner presented to the fertility clinic for evaluation after one year of failing to conceive. The patient’s partner had been treated throughout the conception of their first three pregnancies for ADHD with methylphenidate (Ritalin) for many years; however, eight months prior to presentation at the clinic, the partner had been switched to amphetamine-dextroamphetamine (Adderall) for treatment of ADHD. A fertility evaluation revealed azoospermia which was confirmed via two separate semen analyses two weeks apart. In addition, the patient’s total testosterone, prolactin, luteinizing hormone, and follicle-stimulating hormone were below normal limits. A normal semen analysis was obtained after a five-month withdrawal of amphetamine-dextroamphetamine, which was followed by a naturally conceived pregnancy. The possibility of pre-testicular azoospermia caused by medication-induced pituitary failure should be considered in males prescribed stimulant medication who are seeking to reproduce.

Abatement of the dysfunctional hypothalamic-pituitary-gonadal axis due to ciprofloxacin administration by selenium in male rats

The present study examined the influence of selenium on ciprofloxacin-mediated reproductive dysfunction in rats. The research design consisted of five groups of eight animals each. The rats were administered 135 mg/kg body weight of ciprofloxacin per se or simultaneously with selenium at 0.25 and 0.5 mg/kg for 15 uninterrupted days. Antioxidant and inflammatory indices were assayed using the testes, epididymis, and hypothalamus of the animals after sacrifice. Results revealed that ciprofloxacin treatment per se interfered with the reproductive axis as demonstrated by diminished serum hormonal levels, sperm quality, and enzymatic indices of testicular function, which were, however, abrogated following selenium co-treatment. Besides this, administration of selenium attenuated the depletion of glutathione level, inhibition of catalase, superoxide dismutase, glutathione-S-transferase and glutathione peroxidase activities with a concomitant reduction in reactive oxygen and nitrogen species, and lipid peroxidation in ciprofloxacin-treated in rats. Selenium treatment also mitigated ciprofloxacin-mediated elevation in nitric oxide level and of myeloperoxidase activity as well as histological lesions in the animals. Overall, selenium attenuated impairment in the male reproductive axis due to ciprofloxacin treatment through abatement of inflammation and oxidative stress in rats.

Chlorogenic acid co-administration abates tamoxifen-mediated reproductive toxicities in male rats: An experimental approach

Reports over the years have demonstrated toxic side effect-including reproductive toxicity- of tamoxifen (TAM), a drug of choice in the management of primary breast cancer. Chlorogenic acid (CGA), a dietary polyphenol, reportedly elicits beneficial pharmacological effects. However, the impact of CGA on TAM-associated reproductive toxicity is absent in the literature. We, therefore, experimented on CGA's effect and TAM-mediated reproductive toxicity in rats. Cohorts of rats were treated with TAM (50 mg/kg) or co-treated with CGA (25 or 50 mg/kg) for 14 consecutive days. The result showed that treatment of CGA significantly increases testosterone, LH, and FSH levels compared to the TAM group. However, prolactin level was markedly decreased after pretreatment of CGA in TAM-treated rats. CGA abated TAM-induced decreases acid phosphatase, alkaline phosphatase, and antioxidant enzymes in the testis. CGA alleviated TAM-facilitated surges of reactive oxygen and nitrogen species, myeloperoxidase, nitric oxide, interleukin-1β, and tumor necrosis factor-alpha in rats epididymis and testes. Additionally, CGA increased anti-inflammatory cytokine -interleukin-10-, suppressed caspase-3 activity, and reduced pathological lesions in the examined organs of rats co-treated with CGA and TAM. CGA phytoprotective effect improved reproductive function occasioned by TAM-mediated toxicities in rats, by abating oxido-inflammatory damages and downregulating apoptotic responses. PRACTICAL APPLICATIONS: CGA protects against the damaging oxido-inflammatory responses incumbent on TAM metabolism. As an antioxidant abundant in plant-derived foods, CGA reportedly protects against inflammatory damage, hypertension, and neurodegenerative diseases. We present evidence that CGA ameliorates TAM-induced reproductive dysfunction by suppressing oxidative and inflammation stress downregulate apoptosis and improve reproductive function biomarker in rats.

Oligoasthenoteratospermia and sperm tail bending in PPP4C-deficient mice

Protein phosphatase 4 (PPP4) is a protein phosphatase that, although highly expressed in the testis, currently has an unclear physiological role in this tissue. Here, we show that deletion of PPP4 catalytic subunit gene Ppp4c in the mouse causes male-specific infertility. Loss of PPP4C, when assessed by light microscopy, did not obviously affect many aspects of the morphology of spermatogenesis, including acrosome formation, nuclear condensation and elongation, mitochondrial sheaths arrangement and '9 + 2' flagellar structure assembly. However, the PPP4C mutant had sperm tail bending defects (head-bent-back), low sperm count, poor sperm motility and had cytoplasmic remnants attached to the middle piece of the tail. The cytoplasmic remnants were further investigated by transmission electron microscopy to reveal that a defect in cytoplasm removal appeared to play a significant role in the observed spermiogenesis failure and resulting male infertility. A lack of PPP4 during spermatogenesis causes defects that are reminiscent of oligoasthenoteratospermia (OAT), which is a common cause of male infertility in humans. Like the lack of functional PPP4 in the mouse model, OAT is characterized by abnormal sperm morphology, low sperm count and poor sperm motility. Although the causes of OAT are probably heterogeneous, including mutation of various genes and environmentally induced defects, the detailed molecular mechanism(s) has remained unclear. Our discovery that the PPP4C-deficient mouse model shares features with human OAT might offer a useful model for further studies of this currently poorly understood disorder.

Neuroendocrine manifestations of Erdheim-Chester disease

Neuroendocrine manifestations are common in Erdheim-Chester disease (ECD) patients. ECD is a rare non-Langerhans form of histiocytosis with multisystemic infiltration. The involvement of the hypothalamo-pituitary axis is common and central diabetes insipidus (CDI) is one of the most common endocrine manifestations in ECD patients. CDI is the first manifestation of ECD in 25%-48% of the cases. Suprasellar region extension, due to the infiltration of ECD lesions, can cause neurologic manifestations by mass effects, such as headache, visual disturbance, and cranial nerve palsies. Recent studies have revealed that disorders affecting anterior pituitary hormones are common in ECD patients. Secondary adrenal insufficiency, secondary hypothyroidism, (adult) growth hormone deficiency, hypogonadotropic hypogonadism, hyperprolactinemia, and hypoprolactinemia can develop as the neuroendocrine manifestations of ECD. Since the symptoms of anterior pituitary hormone deficiencies tend to be nonspecific, the diagnosis of anterior pituitary hormone dysfunctions can be delayed. Some anterior pituitary dysfunctions such as adrenocorticotropic hormone and/or thyroid-stimulating hormone deficiencies can be life-threatening without adequate hormone supplementation therapies. An endocrinological evaluation of the function of the pituitary gland should be performed at the initial diagnosis of ECD. It is important to recognize that endocrine dysfunctions can develop later during the follow-up of ECD.

Predictors of surgical sperm retrieval in non-obstructive azoospermia: summary of current literature

Intracytoplasmic sperm injection (ICSI), combined with surgical sperm retrieval (SR) techniques, is the sole option for patients with non-obstructive azoospermia to achieve fertility; however, with suboptimal results. Given the variability in clinical presentation, the potential role of factors that can predict the likelihood of successful testicular SR needs to be clarified. This article summarizes the current evidence concerning the variables predicting SR success in non-obstructive azoospermic patients with spermatogenic failure. For this, we used 60 articles, including 46 original papers and six meta-analyses. Clinical and laboratory factors, as well as adjuvant therapies and surgical retrieval methods, were the factors most commonly investigated. We found that Klinefelter syndrome, Y chromosome microdeletions in regions AZFa/b, and Sertoli cell-only histopathology were associated with reduced SR success. By contrast, testis volume > 12.5 ml, history of cryptorchidism, use of micro-TESE as the sperm retrieval method, and adjuvant therapy were associated with improved SR success. None of the predictors, alone or combined, provide definitive information about the chances of harvesting sperm in men with non-obstructive azoospermia, except for Y chromosome microdeletions in regions AZFa/b. In the latter, SR success is virtually nil. We conclude that SR outcomes in men with non-obstructive azoospermia are difficult to predict based on the existing variables. Although several predictors can be used for patient counseling, their clinical value is limited to either ensure SR success or discourage reproductive urologists from recommending SR to men with non-obstructive azoospermia seeking fertility. A notable exception includes the deletions involving the regions AZFa and/or AZFb of the Y chromosome; the affected patients should be counseled against undergoing SR.

Testosterone undecanoate supplementation together with human chorionic gonadotropin does not impair spermatogenesis in males with isolated hypogonadotropic hypogonadism: a retrospective study

Gonadotropin therapy is commonly used to induce virilization and spermatogenesis in male isolated hypogonadotropic hypogonadism (IHH) patients. In clinical practice, 5.6%–15.0% of male IHH patients show poor responses to gonadotropin treatment; therefore, testosterone (T) supplementation can serve as an alternative therapy to normalize serum T levels and promote virilization. However, treatment with exogenous T impairs spermatogenesis and suppresses intratesticular T levels. This retrospective study aimed to determine whether oral testosterone undecanoate (TU) supplementation together with human chorionic gonadotropin (hCG) would negatively affect spermatogenesis in IHH patients compared with hCG alone. One hundred and seven IHH patients were included in our study. Fifty-four patients received intramuscular hCG and oral TU, and 53 patients received intramuscular hCG alone. The median follow-up time was 29 (range: 12–72) months in both groups. Compared with the hCG group, the hCG/TU group required a shorter median time to normalize serum T levels (P < 0.001) and achieve Tanner stage (III and V) of pubic hair and genital development (P < 0.05). However, there were no significant differences in the rate of seminal spermatozoa appearance, sperm concentration, or median time to achieve different sperm concentration thresholds between the groups. In addition, there were no significant differences in side effects, such as acne and gynecomastia, observed in both groups. This study indicates that oral TU supplementation together with hCG does not impair spermatogenesis in treated IHH patients compared with hCG alone, and it shortens the time to normalize serum T levels and promote virilization.

Redox Regulation and Oxidative Stress: The Particular Case of the Stallion Spermatozoa

Redox regulation and oxidative stress have become areas of major interest in spermatology. Alteration of redox homeostasis is recognized as a significant cause of male factor infertility and is behind the damage that spermatozoa experience after freezing and thawing or conservation in a liquid state. While for a long time, oxidative stress was just considered an overproduction of reactive oxygen species, nowadays it is considered as a consequence of redox deregulation. Many essential aspects of spermatozoa functionality are redox regulated, with reversible oxidation of thiols in cysteine residues of key proteins acting as an “on–off” switch controlling sperm function. However, if deregulation occurs, these residues may experience irreversible oxidation and oxidative stress, leading to malfunction and ultimately death of the spermatozoa. Stallion spermatozoa are “professional producers” of reactive oxygen species due to their intense mitochondrial activity, and thus sophisticated systems to control redox homeostasis are also characteristic of the spermatozoa in the horse. As a result, and combined with the fact that embryos can easily be collected in this species, horses are a good model for the study of redox biology in the spermatozoa and its impact on the embryo.

Evidence for Bisphenol B Endocrine Properties: Scientific and Regulatory Perspectives

BACKGROUND

The substitution of bisphenol A (BPA) by bisphenol B (BPB), a very close structural analog, stresses the need to assess its potential endocrine properties.

OBJECTIVE

This analysis aimed to investigate whether BPB has endocrine disruptive properties in humans and in wildlife as defined by the World Health Organization (WHO) definition used in the regulatory field, that is, a) adverse effects, b) endocrine activity, and c) plausible mechanistic links between the observed endocrine activity and adverse effects.

METHODS

We conducted a systematic review to identify BPB adverse effects and endocrine activities by focusing on animal models and in vitro mechanistic studies. The results were grouped by modality (estrogenic, androgenic, thyroid hormone, steroidogenesis-related, or other endocrine activities). After critical analysis of results, lines of evidence were built using a weight-of-evidence approach to establish a biologically plausible link. In addition, the ratio of BPA to BPB potency was reported from studies investigating both bisphenols.

RESULTS

Among the 36 articles included in the analysis, 3 subchronic studies consistently reported effects of BPB on reproductive function. In rats, the 28-d and 48-week studies showed alteration of spermatogenesis associated with a lower height of the seminiferous tubules, the alteration of several sperm parameters, and a weight loss for the testis, epididymis, and seminal vesicles. In zebrafish, the results of a 21-d reproductive study demonstrated that exposed fish had a lower egg production and a lower hatching rate and viability. The in vitro and in vivo mechanistic data consistently demonstrated BPB's capacity to decrease testosterone production and to exert an estrogenic-like activity similar to or greater than BPA's, both pathways being potentially responsible for spermatogenesis impairment in rats and fish.

CONCLUSION

The available in vivo, ex vivo, and in vitro data, although limited, coherently indicates that BPB meets the WHO definition of an endocrine disrupting chemical currently used in a regulatory context. https://doi.org/10.1289/EHP5200.

Interventions to Prevent Sperm DNA Damage Effects on Reproduction

Excessive oxidation and antioxidant imbalance resulting from several conditions may cause sperm DNA damage, which, in turn, affect male fertility, both natural and assisted. Sperm DNA damage transferred to the embryo might also affect the health of offspring. Several conditions associated with excessive oxidative stress are modifiable by the use of specific treatments, lifestyle changes, and averting exposure to environmental/occupational toxicants. Here, we discuss the strategies to reduce sperm DNA damage with a focus on clinical and surgical interventions.

Soy Isoflavones Improve the Spermatogenic Defects in Diet-Induced Obesity Rats through Nrf2/HO-1 Pathway

Soy isoflavones (SIF) are biologically active compounds of non-steroidal and phenolic properties that are richly present in soybeans, which can reduce the body weight and blood lipids of obese animals. Recently, SIF have been reported to affect reproductive ability in obese male rats. However, the specific mechanism has not been well defined. The aim of the current study was to study the possible mechanisms for the effect of SIF administration on obesity induced spermatogenic defects. Obese rats model induced by high-fat diets were established and gavage treated with 0, 50,150 or 450 mg of SIF/kg body weight/day for 4 weeks. Here, our research shows that obesity resulted in spermatogenic degeneration, imbalance of reproductive hormone, testicular oxidative stress and germ cell apoptosis, whereas evidently recovery effects were observed at 150 and 450 mg/kg SIF. We also have discovered that 150 and 450 mg/kg SIF can activate Nrf2/HO-1 pathway in control of Bcl-2, BAX and cleaved caspase-3 expression with implications in antioxidant protection. Our study indicates the potential mechanism of SIF regulating spermatogenic function in obese rats, and provides a scientific experimental basis for the regulation of biological function of obese male reproductive system by SIF.

Multiple signaling pathways in Sertoli cells: recent findings in spermatogenesis

The functions of Sertoli cells in spermatogenesis have attracted much more attention recently. Normal spermatogenesis depends on Sertoli cells, mainly due to their influence on nutrient supply, maintenance of cell junctions, and support for germ cells' mitosis and meiosis. Accumulating evidence in the past decade has highlighted the dominant functions of the MAPK, AMPK, and TGF-β/Smad signaling pathways during spermatogenesis. Among these pathways, the MAPK signaling pathway regulates dynamics of tight junctions and adherens junctions, proliferation and meiosis of germ cells, proliferation and lactate production of Sertoli cells; the AMPK and the TGF-β/Smad signaling pathways both affect dynamics of tight junctions and adherens junctions, as well as the proliferation of Sertoli cells. The AMPK signaling pathway also regulates lactate supply. These signaling pathways combine to form a complex regulatory network for spermatogenesis. In testicular tumors or infertile patients, the activities of these signaling pathways in Sertoli cells are abnormal. Clarifying the mechanisms of signaling pathways in Sertoli cells on spermatogenesis provides new insights into the physiological functions of Sertoli cells in male reproduction, and also serves as a pre-requisite to identify potential therapeutic targets in abnormal spermatogenesis including testicular tumor and male infertility.