Standards in semen examination: publishing reproducible and reliable data based on high-quality methodology.

Biomedical science is rapidly developing in terms of more transparency, openness and reproducibility of scientific publications. This is even more important for all studies that are based on results from basic semen examination. Recently two concordant documents have been published: the 6th edition of the WHO Laboratory Manual for the Examination and Processing of Human Semen, and the International Standard ISO 23162:2021. With these tools, we propose that authors should be instructed to follow these laboratory methods in order to publish studies in peer-reviewed journals, preferable by using a checklist as suggested in an Appendix to this article.

OXIDATIVE STRESS AND REPRODUCTIVE FUNCTION: Sperm telomeres, oxidative stress, and infertility.

In brief: Oxidative stress is recognized as an underlying driving factor of both telomere dysfunction and human subfertility/infertility. This review briefly reassesses telomere integrity as a fertility biomarker before proposing a novel, mechanistic rationale for the role of oxidative stress in the seemingly paradoxical lengthening of sperm telomeres with aging. Abstract: The maintenance of redox balance in the male reproductive tract is critical to sperm health and function. Physiological levels of reactive oxygen species (ROS) promote sperm capacitation, while excess ROS exposure, or depleted antioxidant defenses, yields a state of oxidative stress which disrupts their fertilizing capacity and DNA structural integrity. The guanine moiety is the most readily oxidized of the four DNA bases and gets converted to the mutagenic lesion 8-hydroxy-deoxyguanosine (8-OHdG). Numerous studies have also confirmed oxidative stress as a driving factor behind accelerated telomere shortening and dysfunction. Although a clear consensus has not been reached, clinical studies also appear to associate telomere integrity with fertility outcomes in the assisted reproductive technology setting. Intriguingly, while sperm cellular and molecular characteristics make them more susceptible to oxidative insult than any other cell type, they are also the only cell type in which telomere lengthening accompanies aging. This article focuses on the oxidative stress response pathways to propose a mechanism for the explanation of this apparent paradox.

Identification of Arvicola terrestris scherman Sperm Antigens for Immune Contraceptive Purposes.

The cyclical proliferation of the wild fossorial rodent Arvicola terrestris scherman (ATS) is critical in mid-mountain ecosystems of several European countries. Our goal is to develop an immunocontraceptive vaccine to control their fertility, as a sustainable alternative to chemical poisons currently used. Indeed, these chemicals cause the death of ATS predators and animals sharing their ecosystem, and current laws progressively limit their use, making the development of a targeted vaccination strategy an interesting and efficient alternative. In order to identify species-specific sperm antigens, male and female ATS received subcutaneous injections of whole ATS spermatozoa to elicit an immune response. The analysis of the immune sera led to the identification of 120 immunogenic proteins of sperm cells. Of these, 15 were strictly sperm-specific and located in different regions of the male gamete. Some of these antigens are proteins involved in molecular events essential to the reproductive process, such as sperm-egg interaction, acrosomal reaction, or sperm motility. This approach not only identified a panel of immunogenic proteins from ATS sperm cells, but also demonstrated that some of these proteins trigger an immune response in both male and female ATS. These spermatic antigens are good candidates for the development of a contraceptive vaccine.

Oxidative Damage to Sperm DNA: Attack and Defense.

Due to its particular "silent" metabolic state, without transcription or translation, and a low level of cytosolic protective activities, mature sperm is a cellular type of aerobic organisms particularly at risk of oxidative damage. Despite the efforts of the male genital tract to treat this problem, a subcellular compartment of the sperm, the nucleus, and consequently, the paternal DNA cannot be effectively protected. There is an accumulation of evidence that oxidative damage to sperm DNA is quite common in male infertilities/subfertilities with potential harmful impacts on reproductive success, including the transgenerational inheritance of a paternal chromosomal lot carrying mutations.

Slc26a3 deficiency is associated with epididymis dysplasia and impaired sperm fertilization potential in the mouse.

Members of the solute carrier 26 (SLC26) family have emerged as important players in mediating anions fluxes across the plasma membrane of epithelial cells, in cooperation with the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel. Among them, SLC26A3 acts as a chloride/bicarbonate exchanger, highly expressed in the gastrointestinal, pancreatic and renal tissues. In humans, mutations in the SLC26A3 gene were shown to induce congenital chloride-losing diarrhea (CLD), a rare autosomal recessive disorder characterized by life-long secretory diarrhea. In view of some reports indicating subfertility in some male CLD patients together with SLC26-A3 and -A6 expression in the male genital tract and sperm cells, we analyzed the male reproductive parameters and functions of SLC26A3 deficient mice, which were previously reported to display CLD gastro-intestinal features. We show that in contrast to Slc26a6, deletion of Slc26a3 is associated with severe lesions and abnormal cytoarchitecture of the epididymis, together with sperm quantitative, morphological and functional defects, which altogether compromised male fertility. Overall, our work provides new insight into the pathophysiological mechanisms that may alter the reproductive functions and lead to male subfertility in CLD patients, with a phenotype reminiscent of that induced by CFTR deficiency in the male genital tract.

Investigation of antioxidant systems in human meibomian gland and conjunctival tissues.

Oxidative stress (OS) associated with direct contact with the environment and light exposure is a very potent and continuous stressor of the ocular surface and internal structures of the eye that are required to manage its effects. Constant replenishment of tears together with the superficial lipid layer produced by the meibomian glands (MG) is one protective mechanism. The lipid-rich fraction of the tears coats the deeper aqueous fraction, preventing its evaporation. However, lipids are particularly sensitive to oxidative damage that could alter tear film quality. To counteract oxidative damage, MG along with other structures of the ocular surface use primary antioxidant (AO) systems to limit OS damage such as lipid peroxidation. Limited information concerning the primary enzymatic AO system of the human MG prompted this investigation. Using different approaches (RT-PCR, enzymatic activity assays and immuno-fluorescent microscopy), we determined the presence, distribution and subcellular locations of the major AO enzymes belonging to the classical catalytic triad (superoxide dismutase, catalase and glutathione peroxidases) in adult human MG and conjunctiva (Conj). We showed that both tissues exhibit glutathione peroxidase expression. In addition to the ubiquitous cytosolic GPx1 protein, there was significant expression of GPx2, GPx4 and GPx7. These isoforms are known to preferentially scavenge phospholipid-hydroperoxide compounds. This characterization of the primary AO system of human MG and Conj may help pave the way for the development of diagnostic procedures and have implications for treatment of common MG dysfunction (MGD) and dry eye syndrome (DES).

Liver X Receptors (LXRs) Alpha and Beta Play Distinct Roles in the Mouse Epididymis.

After its production in the testis, a spermatozoon has to undergo posttesticular maturation steps to become fully motile and fertile. The first step is epididymal maturation, during which immature spermatozoa are transformed into biochemically mature cells ready to proceed to the next step, capacitation, a physiological process occurring in the female genital tract. The biochemical transformations include modification of sperm lipid composition during epididymal transit, with significant changes in fatty acids, phospholipids, and sterols between the caput and the cauda epididymal spermatozoa. Although quantitative aspects of these changes are well documented for several mammalian species, molecular mechanisms governing these steps are poorly understood. Transgenic male mice invalidated for the two liver X receptors (LXRalpha and LXRbeta, nuclear oxysterol receptors regulating cholesterol and lipid metabolism) become sterile when aging, showing an epididymal phenotype. We used single-knockout-model mice to characterize the role of each LXR isoform during sperm maturation in the epididymis. We show here that although a certain redundancy exists in the functions of the two LXR isoforms, some physiological processes are more under the influence of only one of them. In both cases, aging males showed slight subfertility, associated with dyslipidemia, emphasizing the importance of lipid metabolism in relation with male fertility.

Effect of Advanced Glycation end Products (AGEs) on Sperm Parameters and Function in C57Bl/6 Mice.

This study investigated the deleterious impact of advanced glycation end products (AGEs), commonly present in metabolic disorders like diabetes, obesity, and infertility-related conditions, on sperm structure and function using a mouse model where AGE generation was heightened through dietary intervention. Five-week-old C57BL/6 mice were divided into two groups, one on a regular diet (control) and the other on an AGE-rich diet. After 13 weeks, various parameters were examined, including fasting blood glucose, body weight, food consumption, sperm parameters and function, testicular superoxide dismutase levels, malondialdehyde content, total antioxidant capacity, Johnson score, AGE receptor (RAGE) content, and carboxymethyl lysine (CML) content. The results showed that mice in the AGE group exhibited increased body weight and elevated fasting blood glucose levels. Furthermore, the AGE group displayed adverse effects on sperm, including reduced sperm counts, motility, increased morphological abnormalities, residual histone, protamine deficiency, sperm DNA fragmentation, reduced testicular antioxidant capacity, and higher levels of RAGE and CML proteins. These findings underscore the negative impact of AGEs on male reproductive health, particularly within the context of metabolic disorders, emphasizing the crucial role of the AGE/RAGE axis in male infertility, especially in the context of Western dietary patterns.

Transmission electron microscopy reveals the presence of SARS-CoV-2 in human spermatozoa associated with an ETosis-like response.

BACKGROUND: Severe acute syndrome coronavirus 2 can invade a variety of tissues, including the testis. Even though this virus is scarcely found in human semen polymerase chain reaction tests, autopsy studies confirm the viral presence in all testicular cell types, including spermatozoa and spermatids. OBJECTIVE: To investigate whether the severe acute syndrome coronavirus 2 is present inside the spermatozoa of negative polymerase chain reaction-infected men up to 3 months after hospital discharge. MATERIALS AND METHODS: This cross-sectional study included 13 confirmed moderate-to-severe COVID-19 patients enrolled 30-90 days after the diagnosis. Semen samples were obtained and examined with real-time polymerase chain reaction for RNA detection and by transmission electron microscopy. RESULTS: In moderate-to-severe clinical scenarios, we identified the severe acute syndrome coronavirus 2 inside spermatozoa in nine of 13 patients up to 90 days after discharge from the hospital. Moreover, some DNA-based extracellular traps were reported in all studied specimens. DISCUSSION AND CONCLUSION: Although severe acute syndrome coronavirus 2 was not present in the infected men's semen, it was intracellularly present in the spermatozoa till 3 months after hospital discharge. The Electron microscopy (EM) findings also suggest that spermatozoa produce nuclear DNA-based extracellular traps, probably in a cell-free DNA-dependent manner, similar to those previously described in the systemic inflammatory response to COVID-19. In moderate-to-severe cases, the blood-testes barrier grants little defence against different pathogenic viruses, including the severe acute syndrome coronavirus 2. The virus could also use the epididymis as a post-testicular route to bind and fuse to the mature spermatozoon and possibly accomplish the reverse transcription of the single-stranded viral RNA into proviral DNA. These mechanisms can elicit extracellular cell-free DNA formation. The potential implications of our findings for assisted conception must be addressed, and the evolutionary history of DNA-based extracellular traps as preserved ammunition in animals' innate defence might improve our understanding of the severe acute syndrome coronavirus 2 pathophysiology in the testis and spermatozoa.

Viruses, bacteria and parasites: infection of the male genital tract and fertility.

BACKGROUND: Infertility affects one couple out of six worldwide. Male infertilty can result from congenital or acquired factors, of which pathogens that reach the genital tract through sexual contact or blood dissemination. The impact of major viral, bacterial and parasitic infections on the male genital tract and fertility has been summarized. RESULTS AND CONCLUSIONS: A systematic review of articles published in the Google Scholar and PubMed databases was conducted. It turns out that viruses, as well as bacteria and parasites are major inducers of male genital tract infections and ensuing infertility through damage to the organs and subsequent loss of function and/or through direct damage to the sperm cells. Moreover, not only male infertility results from such infections but these can also be transmitted to women and even to the offspring, thus highlighting the need to efficiently detect, treat and prevent them.

RéSUMé: CONTEXTE: L'infertilité affecte un couple sur six dans le monde. L'infertilité masculine peut être due à des facteurs congénitaux ou acquis, parmi lesquels des pathogènes qui atteignent le tractus génital par contact sexuel ou dissémination par voie sanguine. Cette revue présente les principaux pathogènes d'origine virale, bactérienne et parasitaire qui affectent le tractus génital masculin et leur impact sur la fertilité. RéSULTATS ET CONCLUSION: Une revue systématique de la littérature a été conduite à partir de Google Scholar et de PubMed. Il apparaît que les virus, au même titre que les bactéries ou les parasites, sont des facteurs majeurs d'infection du tractus génital masculin et d'infertilité. Cette dernière découle de dommages aux organes reproducteurs et à leur perte de fonction et/ou d'atteintes directes aux spermatozoïdes. De plus, ces infections n'impactent pas seulement la fertilité masculine, mais elles peuvent également être transmises aux partenaires féminines et même à la descendance, ce qui souligne l'importance de les détecter, de les traiter et de les prévenir efficacement.

Serum lipid profile levels and semen quality: new insights and clinical perspectives for male infertility and men's health.

PURPOSE: Several clinical scenarios regulate the final ejaculated semen, which is pivotal to reproductive success. Sperm motility and plasma membrane fusogenic activity primarily rely on the peculiar sperm lipid composition, influenced by the patient's metabolism, genetics, nutritional, environmental status, and concomitant clinical entities such as varicocele. This study aimed to determine the relationship between serum lipid profile and testicular function (semen quality and testosterone levels). METHODS: This retrospective study uses medical charts of 278 infertile men who attended andrological care between 2000 and 2019. Seminal analysis data, lipid profile, and total serum testosterone were collected. A multiple linear regression analysis was performed to evaluate the influence of the lipid parameters on the seminal variables. Statistical analyses were carried out with p ≤ 0.05 considered statistically significant. RESULTS: Seminal creatine kinase activity (p = 0.024) is negatively related to HDL (p = 0.032) and triglycerides (p = 0.037), while total testosterone (p < 0.0001) and seminal volume (p = 0.046) appeared both to be negatively related to triglycerides (p = 0.030 and p = 0.033, respectively). CONCLUSION: Medical advice commonly advocated to prevent endothelial dysfunction and cardiovascular disease and improve HDL-cholesterol and triglyceride levels in dyslipidemic patients should also be given to infertile men. Physicians should give patients a thorough assessment, including the blood lipid profile, hormonal status, and routine seminal examinations. We propose a more comprehensive men´s health check-up for the infertile male population, not limited to a simple evaluation of basic sperm parameters.

Spermatozoa isolation with Felix™ outperforms conventional density gradient centrifugation preparation in selecting cells with low DNA damage.

BACKGROUND: The optimization of spermatozoa preparation techniques in order to obtain cell fractions enriched with structurally and functionally "superior" spermatozoa is a key objective of the assisted reproduction industry. OBJECTIVES: The purpose of this study was to evaluate a recent development of an electrophoretic spermatozoa separation device (Felix™, Memphasys Ltd, Sydney, Australia) and to compare its performance with conventional spermatozoa preparation by density gradient centrifugation (DGC). Particular attention was paid to the evaluation of sperm DNA/nuclear integrity. MATERIALS & METHODS: A cohort of 29 human semen samples was studied. Semen samples were analyzed fresh and after DGC or Felix™ preparation. Semen parameters monitored included sample volume, sperm count, total motility, progressive motility, sperm DNA fragmentation using the Sperm Chromatin Structure Assay and sperm DNA oxidation. RESULTS: Spermatozoa preparation with Felix™ resulted in significantly improved spermatozoa fractions with higher progressive motility, lower sperm DNA fragmentation, and lower sperm DNA oxidation compared with raw semen and DGC-prepared spermatozoa. DISCUSSION & CONCLUSION: The data collected in this study support the preparation of spermatozoa by the Felix™ system as it allows selection of spermatozoa with the highest progressive motility as well as the lowest nuclear/DNA damage. These improved sperm parameters, along with the fact that the Felix™ separation process is very fast and highly standardized, should be of great interest to the assisted reproduction technologies industry.

Loss of Nuclear/DNA Integrity in Mouse Epididymal Spermatozoa after Short-Term Exposure to Low Doses of Dibutyl Phthalate or Bisphenol AF and Its Mitigation by Oral Antioxidant Supplementation.

Routine exposure to chemicals omnipresent in the environment, particularly the so-called endocrine-disrupting chemicals (EDCs), has been associated with decreased sperm quality and increased anomalies in testis. The decline in semen quality and testicular abnormalities have been attributed to the disruption of endocrine signaling as well as oxidative stress. The present study set out to examine the effect of short-term exposure of two common EDCs widely used in the plastic industry: Dibutyl Phthalate (DBP) and Bisphenol AF (BPAF). Our research objective was to focus on the post-testicular compartment of the epididymis, where spermatozoa acquire their functional capacity and are stored. The data obtained indicated no significant effect for either chemicals on sperm viability, motility or acrosome integrity. Neither of the EDCs had a noticeable effect on the structures of the testis and epididymis. However, substantial impact on the integrity of the sperm nucleus and DNA structure was evidenced by a significant increase in nuclear decondensation and DNA base oxidation. The damage observed was postulated to arise from the pro-oxidant properties of the EDCs generating excess of reactive oxygen species (ROS) and triggering a state of oxidative stress. This hypothesis was confirmed when the observed damage was largely blocked by co-administering EDCs with an evidenced-based antioxidant formulation.

Epidemiology of sperm DNA fragmentation in a retrospective cohort of 1191 men.

BACKGROUND: The scientific and clinical communities now recognize that sperm DNA integrity is crucial for successful fertilization, good embryo development, and offspring quality of life. Despite the apparent unanimity, this criterion is rarely evaluated in clinical practice. We evaluated the sperm DNA fragmentation index of nearly 1200 sperm samples and its connections based on the patient's age, body mass index, the season of sperm collection, geographical location, medical history, and addictive behaviors. METHODS: A cohort of 1503 patients who were referred to the Royan Institute between July 2018 and March 2020 was examined. Only 1191 patient records with demographic data, complete semen analysis, and DNA fragmentation index measurements were included in the final cohort. Documents were classified, incorporated into statistical models, and analyzed. RESULTS: The results confirmed previous findings that the sperm DNA fragmentation index was significantly higher in aging men. The sperm DNA fragmentation index and high DNA stainability levels were significantly higher in spring and summer samples than in those of other seasons. No correlation was found between semen DNA fragmentation index and patient body mass index, although the study cohort was significantly overweight. Contrary to what might be expected, we observed that the sperm DNA fragmentation index was higher in rural than in urban patients. Intriguingly, epileptic patients exhibited significantly higher sperm DNA fragmentation index levels. DISCUSSION AND CONCLUSION: Age is the factor that is most strongly associated with sperm DNA fragmentation index levels. Our analysis of 1191 samples indicates that between the ages of 19 and 59, the sperm DNA fragmentation index increases by an average of 2% each year. Intriguingly, from an epidemiological perspective, the warm season (spring/summer) is associated with a higher sperm DNA fragmentation index in the study population, possibly due to the deleterious effect of temperature on sperm quality. Some neurological diseases, such as epilepsy, are associated with decreased sperm DNA integrity. This observation could be related to the iatrogenic effects of associated therapies. In the study cohort, body mass index did not appear to be correlated with the DNA fragmentation index.

Three-dimensional imaging of vascular development in the mouse epididymis.

Long considered an accessory tubule of the male reproductive system, the epididymis is proving to be a key determinant of male fertility. In addition to its secretory role in ensuring functional maturation and survival of spermatozoa, the epididymis has a complex immune function. Indeed, it must manage both peripheral tolerance to sperm antigens foreign to the immune system and the protection of spermatozoa as well as the organ itself against pathogens ascending the epididymal tubule. Although our knowledge of the immunobiology of this organ is beginning to accumulate at the molecular and cellular levels, the organization of blood and lymphatic networks of this tissue, important players in the immune response, remains largely unknown. In the present report, we have taken advantage of a VEGFR3:YFP transgenic mouse model. Using high-resolution three-dimensional (3D) imaging and organ clearing coupled with multiplex immunodetections of lymphatic (LYVE1, PDPN, PROX1) and/or blood (PLVAP/Meca32) markers, we provide a simultaneous deep 3D view of the lymphatic and blood epididymal vasculature in the mature adult mouse as well as during postnatal development.

Sperm chromatin structure assay (SCSA®) and flow cytometry-assisted TUNEL assay provide a concordant assessment of sperm DNA fragmentation as a function of age in a large cohort of approximately 10,000 patients.

BACKGROUND: Sperm DNA integrity is increasingly seen as a critical characteristic determining reproductive success, both in natural reproduction and in assisted reproductive technologies (ART). Despite this awareness, sperm DNA and nuclear integrity tests are still not part of routine examinations for either infertile men or fertile men wishing to assess their reproductive capacity. This is not due to the unavailability of DNA and sperm nuclear integrity tests. On the contrary, several relevant but distinct tests are available and have been used in many clinical trials, which has led to conflicting results and confusion. The reasons for this are mainly the lack of standardization between different clinics and between the tests themselves. In addition, the small number of samples analyzed in these trials has often weakened the value of the analyses performed. In the present work, we used a large cohort of semen samples, covering a wide age range, which were simultaneously evaluated for sperm DNA fragmentation (SDF) using two of the most frequently used SDF assays, namely the TUNEL assay and the sperm chromatin structure assay (SCSA®). At the same time, as standard seminal parameters (sperm motility, sperm morphology, sperm count) were available for these samples, correlations between age, SDF and conventional seminal parameters were analyzed. RESULTS: We show that the SCSA® and TUNEL assessments of SDF produce concordant data. However, the SDF assessed by TUNEL is systematically lower than that assessed by SCSA®. Regardless of the test used, the SDF increases steadily during aging, while the HDS parameter (High DNA stainability assessed via SCSA®) remains unchanged. In the cohort analyzed, conventional sperm parameters do not seem to discriminate with aging. Only sperm volume and motility were significantly lower in the oldest age group analyzed [50-59 years of age]. CONCLUSIONS: In the large cohort analyzed, SDF is an age-dependent parameter, increasing linearly with aging. The SCSA® assessment of SDF and the flow cytometry-assisted TUNEL assessment are well correlated, although TUNEL is less sensitive than SCSA®. This difference in sensitivity should be taken into account in the final assessment of the true level of fragmentation of the sperm nucleus of a given sample. The classical sperm parameters (motility, morphology, sperm count) do not change dramatically with age, making them inadequate to assess the fertility potential of an individual.

RéSUMé: CONTEXTE: l'intégrité de l'ADN des spermatozoïdes est de plus en plus considérée comme une caractéristique essentielle déterminant le succès de la reproduction, tant dans la reproduction naturelle que dans les techniques de reproduction assistée (AMP). Malgré cette prise de conscience, les tests d'intégrité nucléaire des spermatozoïdes ne font toujours pas partie des examens de routine pour les hommes infertiles ou fertiles souhaitant évaluer leur capacité de reproduction. Cette situation n'est pas due à l'indisponibilité des tests. Au contraire, plusieurs tests pertinents mais distincts sont disponibles et ont été utilisés dans de nombreux essais cliniques, ce qui a donné lieu à des résultats contradictoires et à une certaine confusion. Les raisons en sont principalement le manque de normalisation entre les différentes cliniques et entre les tests eux-mêmes. En outre, le petit nombre d'échantillons analysés dans ces essais a souvent affaibli la valeur des analyses effectuées. Dans le présent travail, nous avons utilisé une vaste cohorte d'échantillons, couvrant une large tranche d'âge, évalués simultanément pour la fragmentation de l'ADN des spermatozoïdes à l'aide de deux des tests les plus fréquemment utilisés, à savoir le test TUNEL et le test de la structure de la chromatine des spermatozoïdes (SCSA®). Parallèlement, comme les paramètres séminaux standard (motilité, morphologie, numération) étaient disponibles pour ces échantillons, les corrélations entre l'âge, le niveau de fragmentation et les paramètres séminaux conventionnels ont été analysées. RéSULTATS: Nous montrons que les évaluations SCSA® et TUNEL produisent des données concordantes. Cependant, le SDF évalué par TUNEL est systématiquement plus faible que celui évalué par SCSA®. Quel que soit le test utilisé, la fragmentation augmente régulièrement au cours du vieillissement, alors que le paramètre HDS (« High DNA stainability¼ évalué par le test SCSA®) reste inchangé. Dans la cohorte analysée, les paramètres spermatiques conventionnels ne semblent pas varier avec le vieillissement. Seuls le volume et la mobilité des spermatozoïdes étaient significativement plus faibles dans le groupe d'âge le plus élevé analysé [50­59 ans]. CONCLUSIONS: Dans la grande cohorte analysée, la fragmentation de l'ADN spermatique est un paramètre dépendant de l'âge, augmentant linéairement avec le vieillissement. L'évaluation du SDF par SCSA® et l'évaluation via le test TUNEL assistée par cytométrie de flux sont bien corrélées, bien que le TUNEL soit moins sensible que le SCSA®. Cette différence de sensibilité doit être prise en compte dans l'évaluation finale du niveau réel de fragmentation du noyau des spermatozoïdes d'un échantillon donné. Les paramètres classiques du sperme (motilité, morphologie, nombre de spermatozoïdes) ne changent pas de façon spectaculaire avec l'âge, ce qui les rend inadéquats pour évaluer le potentiel de fertilité d'un individu.

Deficient tryptophan catabolism along the kynurenine pathway reveals that the epididymis is in a unique tolerogenic state.

Indoleamine 2,3-dioxygenase (IDO) is the first and rate-limiting enzyme of tryptophan catabolism through the kynurenine pathway. Intriguingly, IDO is constitutively and highly expressed in the mammalian epididymis in contrast to most other tissues where IDO is induced by proinflammatory cytokines, such as interferons. To gain insight into the role of IDO in the physiology of the mammalian epididymis, we studied both wild type and Ido1(-/-)-deficient mice. In the caput epididymis of Ido1(-/-) animals, the lack of IDO activity was not compensated by other tryptophan-catabolizing enzymes and led to the loss of kynurenine production. The absence of IDO generated an inflammatory state in the caput epididymis as revealed by an increased accumulation of various inflammation markers. The absence of IDO also increased the tryptophan content of the caput epididymis and generated a parallel increase in caput epididymal protein content as a consequence of deficient proteasomal activity. Surprisingly, the lack of IDO expression had no noticeable impact on overall male fertility but did induce highly significant increases in both the number and the percentage of abnormal spermatozoa. These changes coincided with a significant decrease in white blood cell count in epididymal fluid compared with wild type mice. These data provide support for IDO playing a hitherto unsuspected role in sperm quality control in the epididymis involving the ubiquitination of defective spermatozoa and their subsequent removal.

Liver X receptors, lipids and their reproductive secrets in the male.

Liver X receptor (LXR) α and LXRß belong to the nuclear receptor superfamily. For many years, they have been called orphan receptors, as no natural ligand was identified. In the last decade, the LXR natural ligands have been shown to be oxysterols, molecules derived from cholesterol. While these nuclear receptors have been abundantly studied for their roles in the regulation of lipid metabolism, it appears that they also present crucial activities in reproductive organs such as testis and epididymis, as well as prostate. Phenotypic analyses of mice lacking LXRs (lxr-/-) pointed out their physiological activities in the various cells and organs regulating reproductive functions. This review summarizes the impact of LXR-deficiency in male reproduction, highlighting the novel information coming from the phenotypic analyses of lxrα-/-, lxrß-/- and lxrα;ß-/- mice. This article is part of a Special Issue entitled: Translating nuclear receptor from health to disease.

[Post-testicular protection of male gametes from oxidative damage. The role of the epididymis]. / Protection post-testiculaire des gamètes mâles contre les dommages radicalaires: le rôle de l'épididyme.

Spermatozoa leave the testis in an immature functional state and are devoid of self defense mechanisms. They will become motile and ready to fertilize only after their descent and their progressive maturation within the epididymal tubule. The epididymis also ensures the survival and the protection of male gametes while they go through the epididymis and during their storage in between two ejaculations. Amongst common stresses that concern spermatozoa, oxidative stress occupies a peculiar and dual position. While the events of epididymal sperm maturation necessitate a given level of oxidation, spermatozoa are particularly sensitive to oxidative damage. A fine balance between beneficial oxidation versus detrimental oxidative damage has to be maintained in the epididymal environment. Antioxidant enzymes of the glutathione peroxidase family play a key role in controling such a situation in the epididymis.

The NLRP3 inflammasome: molecular activation and regulation in spermatogenesis and male infertility; a systematic review.

BACKGROUND: Infertility related to varicocele, infections, metabolic dysfunctions, oxidative stress and environmental toxicants is also associated with inflammatory processes that ultimately lead to the activation of the inflammasome pathway (IP). IP is classically activated by DAMPs, MAMPs or LAMPs, which stand for Damage-, Microbe- or Lifestyle-Associated Molecular Patterns, respectively. The most important player in IP activation is the NLRP3 (NOD[Nuclear oligomerization domain]-, LRR[Leucine rich repeat]- and pyrin domain-containing protein 3) which functions as an intracellular sensor of D/M/L-AMPs resulting in activation of caspase-1, promotion of apoptosis, pyroptosis and generation of inflammatory cytokines. This review addresses the question of whether IP activation might be associated with male infertility situations. RESULTS & CONCLUSIONS: We conducted a systematic review of articles published in the Google Scholar, and PubMed databases through October 2021. It turns out that inflammasome activation and its consequences including cytokine storms, apoptosis and pyroptosis could be associated with the reduced sperm count as well as the structural and functional sperm defects recorded in several situations associated with male infertility suggesting that anti-inflammatory therapeutic strategies could be possibly considered to restore male fertility in future research.

RéSUMé: CONTEXTE: L'infertilité liée à la varicocèle, aux infections, aux dysfonctionnements métaboliques, au stress oxydant et aux toxiques environnementaux est. également associée à des processus inflammatoires qui conduisent finalement à l'activation de la voie de l'inflammasome (IP). Cette voie est. classiquement activée par des DAMPs, MAMPs ou LAMPs, qui signifient respectivement Damage-, Microbe- ou Lifestyle-Associated Molecular Patterns. L'acteur le plus important dans l'activation de l'inflammasome est. la protéine NLRP3 (NOD[Nuclear Oligomerization Domain]-, LRR[Leucine Rich Repeat]- and pyrin domain-containing protein 3) qui fonctionne comme un capteur intracellulaire de D/M/L-AMPs résultant en l'activation de la caspase-1, la promotion de l'apoptose, la pyroptose et la génération de cytokines inflammatoires. Cette revue aborde la question de savoir si l'activation de l'inflammasome pourrait être associée à des situations d'infertilité masculine. RéSULTATS ET CONCLUSIONS: Nous avons réalisé une revue systématique des articles publiés dans les bases de données Google Scholar, et PubMed jusqu'en octobre 2021. Il s'avère que l'activation de l'inflammasome et ses conséquences, y compris les "orages" de cytokines, l'apoptose et la pyroptose, pourraient être associées à la réduction du nombre de spermatozoïdes ainsi qu'aux défauts structurels et fonctionnels des spermatozoïdes enregistrés dans plusieurs situations associées à l'infertilité masculine, ce qui suggère que des stratégies thérapeutiques anti-inflammatoires pourraient être éventuellement envisagées pour restaurer la fertilité masculine dans les recherches futures.