Spermatozoa Of Infertile Men Research Articles

Activity of glutathione-dependent enzymes in spermatozoa in patients with pathospermia

The results of glutathione peroxidase and glutathione reductase activity in spermatozoa of patients with different forms pathospermia are presented in the paper. It was shown that glutathione peroxidase and glutathione reductase activity in sperm cells of patients is reduced in comparison with healthy men with preserved fertility. However, the most expressed changes in the activity of glutathione peroxidase and glutathione reductase are in spermatozoa of infertile men with associated forms patospermia and leucospermia. These changes indicate exhaustion of compensatory mechanisms of glutathione antioxidant system in the sperm cells of infertile men with pahospermia.

Na+, K+-ATPase and Ca2+, Mg2+-ATPase activity in spermatozoa of infertile men with different forms of pathospermia

Ion-exchanging ATPases play an essential role in biology of spermatozoa, inclu­ding their motility, hyperactivation, chemotaxis, acrosome reaction etc. The aim of present study was to analyze Na + , K + -ATPase and Ca 2+ , Mg 2+ -ATPase activities in spermatozoa of the infertile men with different forms of pathospermia and to explore a possible role that they may play in male infertility. A significant reduction in ouabain-sensitive Na + , K + -ATPase activity in sperm cells of infertile men with oligozoo-, asthenozoo-, oligoasthenozoo- and leucocytospermia was shown. The results show that asthenozoo-, oligoasthenozoo- and leucocytospermic patients have significantly impaired thapsigargin-sensitive and thapsigargin-insensitive Ca 2 + , Mg 2+ -ATPase activity compared to healthy men. However, Ca 2+ , Mg 2+ -ATPase activity has a tendency to increase in patients with oligozoospermia. The depressed ATPase activity in the infertile men could be due to a reduction in intracellular adenosine triphosphate level and damage of spermal membranes caused by lipid peroxidation products. The most significant decrease in Ca 2 + , Mg 2+ -ATPase activity was observed in patients with leucocytospermia which could be explained by an excessive formation of the reactive oxygen species by the leucocytes. It is suggested that a decrease in the ion-exchanging ATPase activity may damage sperm functions and be one of possible causes of male infertility.

Expression of protocadherin 11Yb (PCDH11Yb) in seminal germ cells is correlated with fertility status in men.

Protocadherin 11 Y-linked (PCDH11Y), a member of the cadherin superfamily, is predominantly expressed in the central nervous system, is encoded by the Yp11.2 locus and exists in three isoforms: 11Ya, 11Yb and 11Yc. PCDH11Y is upregulated by retinoic acid signalling and is essential for spermatogonial differentiation and initiation of meiosis. PCDH11Y mediates Wnt signalling, which plays a crucial role in the differentiation of various cell types. PCDH11Y has been implicated in neuronal cell differentiation and proliferation, but its association with spermatogenesis has not yet been addressed. Hence, in order to address the possible role of PCDH11Y in relation to spermatogenesis, the expression analysis of PCDH11Y in the seminal germ cells of fertile and infertile males were carried out employing RT-PCR, western blotting and immunofluorescence analysis. In the present study, PCDH11Yb, but not PCDH11Ya or PCDH11Yc, was expressed in germ cells isolated from the semen of all 13 men with proven fertility. However, in several subjects from various infertility classes, there was complete absence or a significant reduction in the expression of PCDH11Yb. PCDH11Y exhibited prominent localisation on the head and midpiece region of spermatozoa from fertile men, whereas spermatozoa from infertile subjects had either weak or abnormal localisation patterns for PCDH11Y. In addition, downregulation of canonical Wnt signalling was correlated with defective expression of PCDH11Y in spermatozoa of infertile men, as evidenced by downregulation of the Wnt targets C-Myc and C-Jun. In conclusion, expression levels of PCDH11Yb in germ cells in the semen were correlated with the fertility status of men.

Effect of hydrogen peroxide on the main kinetic parameters of ATP hydrolysis by ouabain sensitive Na+, K+-ATP-ase in spermatozoa of infertile men

Effect of hydrogen peroxide on the main kinetic parameters of ATP hydrolysis by ouabain sensitive Na+, K+-ATP-ase in spermatozoa of infertile men

Glutathione antioxidant protection system in ejaculated spermatozoa of infertile men with different forms of pathospermia

Glutathione antioxidant protection system in ejaculated spermatozoa of infertile men with different forms of pathospermia

Proteolytic degradation of heat shock protein A2 occurs in response to oxidative stress in male germ cells of the mouse.

Does oxidative stress compromise the protein expression of heat shock protein A2 (HSPA2) in the developing germ cells of the mouse testis? Oxidative stress leads to the modification of HSPA2 by the lipid aldehyde 4-hydroxynonenal (4HNE) and initiates its degradation via the ubiquitin-proteasome system. Previous work has revealed a deficiency in HSPA2 protein expression within the spermatozoa of infertile men that have failed fertilization in a clinical setting. While the biological basis of this reduction in HSPA2 remains to be established, we have recently shown that the HSPA2 expressed in the spermatozoa of normozoospermic individuals is highly susceptible to adduction, a form of post-translational modification, by the lipid aldehyde 4HNE that has been causally linked to the degradation of its substrates. This modification of HSPA2 by 4HNE adduction dramatically reduced human sperm-egg interaction in vitro. Moreover, studies in a mouse model offer compelling evidence that the co-chaperone BCL2-associated athanogene 6 (BAG6) plays a key role in regulating the stability of HSPA2 in the testis, by preventing its ubiquitination and subsequent proteolytic degradation. Dose-dependent studies were used to establish a 4HNE-treatment regime for primary culture(s) of male mouse germ cells. The influence of 4HNE on HSPA2 protein stability was subsequently assessed in treated germ cells. Additionally, sperm lysates from infertile patients with established zona pellucida recognition defects were examined for the presence of 4HNE and ubiquitin adducts. A minimum of three biological replicates were performed to test statistical significance. Oxidative stress was induced in pachytene spermatocytes and round spermatids isolated from the mouse testis, as well as a GC-2 cell line, using 50-200 µM 4HNE or hydrogen peroxide (H2O2), and the expression of HSPA2 was monitored via immunocytochemistry and immunoblotting approaches. Using the GC-2 cell line as a model, the ubiquitination and degradation of HSPA2 was assessed using immunoprecipitation techniques and pharmacological inhibition of proteasomal and lysosomal degradation pathways. Finally, the interaction between BAG6 and HSPA2 was examined in response to 4HNE exposure via proximity ligation assays. HSPA2 protein levels were significantly reduced compared with controls after 4HNE treatment of round spermatids (P < 0.01) and GC-2 cells (P < 0.001) but not pachytene spermatocytes. Using GC-2 cells as a model, HSPA2 was shown to be both adducted by 4HNE and targeted for ubiquitination in response to cellular oxidative stress. Inhibition of the proteasome with MG132 prevented HSPA2 degradation after 4HNE treatment indicating that the degradation of HSPA2 is likely to occur via a proteasomal pathway. Moreover, our assessment of proteasome activity provided evidence that 4HNE treatment can significantly increase the proteasome activity of GC-2 cells (P < 0.05 versus control). Finally, 4HNE exposure to GC-2 cells resulted in the dissociation of HSPA2 from its regulatory co-chaperone BAG6, a key mediator of HSPA2 stability in male germ cells. While these experiments were performed using a mouse germ cell-model system, our analyses of patient sperm lysate imply that these mechanisms are conserved between mouse and human germ cells. This study suggests a causative link between non-enzymatic post-translational modifications and the relative levels of HSPA2 in the spermatozoa of a specific sub-class of infertile males. In doing so, this work enhances our understanding of failed sperm-egg recognition and may assist in the development of targeted antioxidant-based approaches for ameliorating the production of cytotoxic lipid aldehydes in the testis in an attempt to prevent this form of infertility. Not applicable. This work was supported by the National Health and Medical Research Council of Australia (APP1101953). The authors have no competing interests to declare.

NO-Synthase Pathway of L-Arginine Transformation in Spermatozoa of Infertile Men with Different Forms of Pathospermia

NO-Synthase Pathway of L-Arginine Transformation in Spermatozoa of Infertile Men with Different Forms of Pathospermia

Evaluation of DNA methylation at imprinted DMRs in the spermatozoa of oligozoospermic men in association with MTHFR C677T genotype.

Altered DNA methylation has been previously identified in the spermatozoa of infertile men; however, the origins of these errors are poorly understood. DNA methylation is an epigenetic modification which is thought to play a fundamental role in male germline development. DNA methylation reactions rely on the cellular availability of methyl donors, which are primarily products of folate metabolism, where a key enzyme is methylenetetrahydrofolate reductase (MTHFR). The MTHFR C677T single nucleotide polymorphism (SNP) reduces enzyme activity and may potentially alter DNA methylation processes during germline development. The objective of this study was to determine whether altered DNA methylation in spermatozoa is associated with the MTHFR C677T SNP. DNA methylation was evaluated at the H19, IG-GTL2, and MEST imprinted differentially methylated regions in the spermatozoa of 53 men - 44 oligozoospermic men and nine fertile men with normal sperm parameters via bisulfite sequencing of sperm clones. The 44 infertile men were stratified by severity of oligozoospermia - three normal (>15million spermatozoa/mL), eight moderate (5-15million spermatozoa/mL), 23 severe (1-5million spermatozoa/mL), and 10 very severe (<1million spermatozoa/mL). MTHFR C677T SNP genotyping was conducted in a subset of 44 peripheral blood samples via restriction fragment length polymorphism. A total of three men - severe oligozoospermic and CT genotype - were found to be altered, which is defined as having ≥50% of their clones altered, where an altered clone was in turn defined as ≥50% of CpGs with incorrect DNA methylation patterns. The incidence of three altered men within the CT subgroup, however, was not significantly higher than the incidence in the CC subgroup. Taken together, altered DNA methylation in spermatozoa was not significantly associated with the MTHFR C677T SNP; however, there was a trend for higher incidence of alterations among severe oligozoospermic infertile men with CT genotypes.

Selection of physiological spermatozoa during intracytoplasmic sperm injection.

Sperm genomic integrity has a significant effect on intracytoplasmic sperm injection (ICSI) outcomes, especially post-implantation. Spermatozoa selected based on motility and morphology do not guarantee the genomic integrity of spermatozoa. Nearly fifty percentage of spermatozoa in infertile men with normal morphology present different degrees of DNA fragmentation. However, capacitated or hyperactivated spermatozoa show lower degrees of DNA fragmentation. Therefore, selection of hyperactivated spermatozoa may improve ICSI outcome. Routinely, for ICSI, fast-moving spermatozoa with A or B motility pattern are mainly selected for injection. The result of this study shows that in processed semen samples, hyperactivated spermatozoa are mainly observed in B motility pattern while, in viscous medium like polyvinylpyrrolidone (PVP), hyperactivated spermatozoa are mainly present in spermatozoa with C pattern of motility (nonprogressive). Therefore, we propose spermatozoa with C motility pattern which contains the main population of physiological or hyperactivated spermatozoa should be selected for ICSI.

On the origin of sperm epigenetic heterogeneity

The influence of epigenetic modifications on reproduction and on the function of male germ cells has been thoroughly demonstrated. In particular, aberrant DNA methylation levels in sperm have been associated with abnormal sperm parameters, lower fertilization rates and impaired embryo development. Recent reports have indicated that human sperm might be epigenetically heterogeneous and that abnormal DNA methylation levels found in the sperm of infertile men could be due to the presence of sperm populations with different epigenetic quality. However, the origin and the contribution of different germ cell types to this suspected heterogeneity remain unclear. In this review, we focus on sperm epigenetics at the DNA methylation level and its importance in reproduction. We take into account the latest developments and hypotheses concerning the functional significance of epigenetic heterogeneity coming from the field of stem cell and cancer biology and discuss the potential importance and consequences of sperm epigenetic heterogeneity for reproduction, male (in)fertility and assisted reproductive technologies (ART). Based on the current information, we propose a model in which spermatogonial stem cell variability, either intrinsic or due to external factors (such as endocrine action and environmental stimuli), can lead to epigenetic sperm heterogeneity, sperm epimutations and male infertility. The elucidation of the precise causes for epimutations, the conception of adequate therapeutic options and the development of sperm selection technologies based on epigenetic quality should be regarded as crucial to the improvement of ART outcome in the near future.

DNA methylation levels of imprinted and nonimprinted genes DMRs associated with defective human spermatozoa.

Asthenozoospermia (AS) is a common cause of human male infertility. Recent studies have shown significant associations of aberrant DNA methylation in spermatozoa with male infertility. The aims of the this investigation were to assess the changes in DNA methylation of known imprinted genes (MEST, GNAS and H19), novel imprinted gene (FAM50B) and nonimprinted genes (LINE-1 and P16) DMRs in the spermatozoa of infertile men with single-factor AS. Semen samples were obtained from 46 AS patients and 49 age-matched normal controls. DNA methylation levels of detected genes DMR were determined by MassARRAY quantitative methylation analysis. The average methylation level at the P16 and MEST DMRs was significantly lower in AS patients than in controls (patients 6.51±0.32%, controls 7.66±0.40%, P<0.01). The methylation level of 6 CpG sites of P16 DMR, and 1 CpG site of MEST, GNAS, FAM50B and LINE-1 DMRs, was lower in AS group than in control group. For the first time, the data presented here suggest that increased methylation defects of P16 DMR may be associated with low sperm motility. This study provides the potential association between low sperm motility infertile men and the aberrant DNA methylation of MEST, LINE-1, GNAS and FAM50B DMRs.

Comparative proteomic analysis indicates underexpression of molecular chaperones in spermatozoa of infertile men

Comparative proteomic analysis indicates underexpression of molecular chaperones in spermatozoa of infertile men

Morphologically distinct phenotypes of spermatozoa in infertile men reveal down regulation of multiple signaling pathways

Seven morphologically distinct spermatozoal phenotypes can be detected in human semen under electron microscopy: sperm with dysplasia of the fibrous sheath, non-specific flagellar defects, immotile cilia syndrome, acrosomal hypoplasia, defective chromatin condensation and compaction, pin head and sperm without heads. These conditions cannot be identified by routine semen analysis because they are but secondary manifestations of underlying pathology. We hypothesize that proteomics would enable us to better understand the mechanism(s) underlying these pathologies.

Epigenetic alterations in sperm associated with male infertility.

The most common form of male infertility is a low sperm count, known as oligozoospermia. Studies suggest that oligozoospermia is associated with epigenetic alterations. Epigenetic alterations in sperm, which may arise due to the exposure of gametes to environmental factors or those that pre-exist in the sperm of infertile individuals, may contribute to the increased incidence of normally rare imprinting disorders in babies conceived after assisted reproductive technology using the sperm of infertile men. Genomic imprinting is an important developmental process whereby the allelic activity of certain genes is regulated by DNA methylation established during gametogenesis. The aberrant expression of several imprinted genes has been linked to various diseases, malignant tumors, lifestyle and mental disorders in humans. Understanding how infertility and environmental factors such as reproductive toxicants, certain foods, and drug exposures during gametogenesis contribute to the origins of these disorders via defects in sperm is of paramount importance. In this review, we discuss the association of epigenetic alterations with abnormal spermatogenesis and the evidence that epigenetic processes, including those required for genomic imprinting, may be sensitive to environmental exposures during gametogenesis, fertilization and early embryonic development. In addition, we review imprinting diseases and their relationships with environmental factors. While the plasticity of epigenetic marks may make these more susceptible to modification by the environment, this also suggests that aberrant epigenetic marks may be reversible. A greater understanding of this process and the function of epidrugs may lead to the development of new treatment methods for many adult diseases in the future.

Evaluation of the association of cigarette smoking with retention of excess cytoplasm by spermatozoa in infertile men

Evaluation of the association of cigarette smoking with retention of excess cytoplasm by spermatozoa in infertile men

Aberrant DNA methylation patterns of spermatozoa in men with unexplained infertility.

Are there DNA methylation alterations in sperm that could explain the reduced biological fertility of male partners from couples with unexplained infertility? DNA methylation patterns, not only at specific loci but also at Alu Yb8 repetitive sequences, are altered in infertile individuals compared with fertile controls. Aberrant DNA methylation of sperm has been associated with human male infertility in patients demonstrating either deficiencies in the process of spermatogenesis or low semen quality. Case and control prospective study. This study compares 46 sperm samples obtained from 17 normospermic fertile men and 29 normospermic infertile patients. Illumina Infinium HD Human Methylation 450K arrays were used to identify genomic regions showing differences in sperm DNA methylation patterns between five fertile and seven infertile individuals. Additionally, global DNA methylation of sperm was measured using the Methylamp Global DNA Methylation Quantification Ultra kit (Epigentek) in 14 samples, and DNA methylation at several repetitive sequences (LINE-1, Alu Yb8, NBL2, D4Z4) measured by bisulfite pyrosequencing in 44 sperm samples. A sperm-specific DNA methylation pattern was obtained by comparing the sperm methylomes with the DNA methylomes of differentiated somatic cells using data obtained from methylation arrays (Illumina 450 K) of blood, neural and glial cells deposited in public databases. In this study we conduct, for the first time, a genome-wide study to identify alterations of sperm DNA methylation in individuals with unexplained infertility that may account for the differences in their biological fertility compared with fertile individuals. We have identified 2752 CpGs showing aberrant DNA methylation patterns, and more importantly, these differentially methylated CpGs were significantly associated with CpG sites which are specifically methylated in sperm when compared with somatic cells. We also found statistically significant (P < 0.001) associations between DNA hypomethylation and regions corresponding to those which, in somatic cells, are enriched in the repressive histone mark H3K9me3, and between DNA hypermethylation and regions enriched in H3K4me1 and CTCF, suggesting that the relationship between chromatin context and aberrant DNA methylation of sperm in infertile men could be locus-dependent. Finally, we also show that DNA methylation patterns, not only at specific loci but also at several repetitive sequences (LINE-1, Alu Yb8, NBL2, D4Z4), were lower in sperm than in somatic cells. Interestingly, sperm samples at Alu Yb8 repetitive sequences of infertile patients showed significantly lower DNA methylation levels than controls. Our results are descriptive and further studies would be needed to elucidate the functional effects of aberrant DNA methylation on male fertility. Overall, our data suggest that aberrant sperm DNA methylation might contribute to fertility impairment in couples with unexplained infertility and they provide a promising basis for future research. This work has been financially supported by Fundación Cientifica de la AECC (to R.G.U.); IUOPA (to G.F.B.); FICYT (to E.G.T.); the Spanish National Research Council (CSIC; 200820I172 to M.F.F.); Fundación Ramón Areces (to M.F.F); the Plan Nacional de I+D+I 2008-2011/2013-2016/FEDER (PI11/01728 to AF.F., PI12/01080 to M.F.F. and PI12/00361 to S.L.); the PN de I+D+I 2008-20011 and the Generalitat de Catalunya (2009SGR01490). A.F.F. is sponsored by ISCIII-Subdirección General de Evaluación y Fomento de la Investigación (CP11/00131). S.L. is sponsored by the Researchers Stabilization Program from the Spanish National Health System (CES09/020). The IUOPA is supported by the Obra Social Cajastur, Spain.

Association of decreased spermatozoa omega-3 fatty acid levels and increased oxidative DNA damage with varicocele in infertile men: a case control study.

Varicocele is commonly associated with male infertility because it impairs normal sperm morphology and activity. Polyunsaturated fatty acids (PUFA) are important determinants of sperm cell structure and function, but their relationship with varicocele remains unclear. The aim of the present study was to investigate the PUFA composition in spermatozoa of infertile men with varicocele and to evaluate the potential relationship between PUFA and varicocele. This case control study recruited 92 infertile men with varicocele, 99 infertile men without varicocele and 95 fertile male control subjects. Semen morphology and activity parameters were assessed and seminal plasma 8-hydroxy-2-deoxyguanosine (8-OHdG) content was determined by ELISA. Sperm concentrations of omega-3 and omega-6 fatty acids were measured by gas chromatography. Infertile men with varicocele had lower concentrations of omega-3 PUFA, higher omega-6:omega-3 PUFA ratios and greater oxidative DNA damage in spermatozoa compared with infertile men without varicocele and normal subjects. The degree of varicocele and DNA damage was associated with decreased omega-3 PUFA concentrations and semen quality in infertile men with varicocele. The findings suggest that omega-3 PUFA deficiency could be implicated in varicocele-associated infertility, and highlight the need for intervention trials to test the usefulness of omega-3 supplementation in reducing sperm abnormalities in infertile men with varicocele.

Effects of Biovar I and Biovar II of Ureaplasma urealyticum on Sperm Parameters, Lipid Peroxidation, and Deoxyribonucleic Acid Damage in Male Infertility

To reveal the impact of 2 biovars of Ureaplasma urealyticum on the sperm of infertile men by producing reactive oxygen species (ROS). A total of 223 infertile and 146 fertile men were recruited into the study. Standard semen analysis was performed. Culturing and real-time polymerase chain reaction were used to identify biovars of U urealyticum in the semen. Semen ROS, malondialdehyde, and total superoxide dismutase levels were measured. Sperm nuclear deoxyribonucleic acid (DNA) damage was assessed of by sperm chromatin structure assay and single-cell gel electrophoresis. Biovar II infection was more frequent in infertile men (P=.036). When compared with uninfected individuals, biovar II-infected men displayed decreases in spermatozoa concentration (P=.041); biovar II and mix-infected men displayed decreases in total motility (P=.015; P=.014, respectively) and increase in leukocyte counts (P=.004; P=.003, respectively). Except for total superoxide dismutase level, indicators for peroxide including ROS level, malondialdehyde level, DNA fragmentation index and high DNA stainable in sperm chromatin structure assay, and tail moment in single-cell gel electrophoresis exhibited the significant differences between both infected groups vs the uninfected group (P<05). Compared with biovar I, biovar II is more likely to cause male infertility. Increased leukocyte counts, ROS level elevation, and subsequent spermatozoa membrane and DNA damage may be involved in this pathogenesis.

Localisation and quantification of alkali-labile sites in human spermatozoa by DNA breakage detection-fluorescencein situhybridisation

The localisation and quantification of constitutive alkali-labile sites (ALSs) were investigated using a protocol of DNA breakage detection plus fluorescence in situ hybridisation (DBD-FISH) and alkaline single-cell gel electrophoresis (SCGE or comet assay), in spermatozoa of infertile and fertile men. Semen samples from 10 normozoospermic patients undergoing infertility treatment and 10 fertile men were included in this study. ALSs were localised and quantified by DBD-FISH. The region most sensitive to alkali treatment in human spermatozoa was located in the basal region of the head. ALSs were more frequent in spermatozoa of infertile men than in those of fertile men. These results were confirmed by SCGE comet assays. In conclusion, the most intense localisation of hybridisation signals in human spermatozoa, representing the highest density of constitutive ALSs, was not randomly distributed and was predominantly located in the base of the head. Moreover, infertile men presented with an increase in ALS frequency. Further studies are necessary to determine the association between ALS, sperm chromatin organisation and infertility.

Increased Oxidative DNA Damage in Seminal Plasma of Infertile Men with Varicocele

Objective: To investigate the oxidative DNA damage in the seminal plasma and spermatozoa of infertile men with varicocele and to evaluate the potential relationship between oxidative DNA damage and varicocele. Methods: This case-control study recruited 180 infertile men with varicocele and 199 infertile men without varicocele and 168 fertile male control subjects. Semen parameters, seminal plasma 8-hydroxy-2-deoxyguanosine (8-OHdG) and sperm DNA Fragmentation Index (DFI) were assessed. Results: Compared to the infertile men without varicocele and control subjects, infertile men with varicocele exhibited lower sperm concentration, lower progressive motility, lower vitality and lower percentage of normal morphology (all P=0.0001). The seminal content of 8-OHdG and sperm DFI were higher in infertile men with varicocele than in infertile men without varicocele and in the control group (all P<0.001). A positive correlation was observed between the 8-OHdG levels and DFI (P<0.001). However, There were negative correlations between seminal plasma 8-OHdG levels or sperm DFI with sperm concentration, progressive motility, vitality, and normal forms in the varicocele group (all P<0.001). Furthermore, the seminal plasma 8-OHdG content and sperm DFI was significantly higher in grades II and III than in grade I after controlling age, BMI, abstinence period and semen parameters. Conclusions: Infertile men with varicocele have greater oxidative DNA damage in seminal plasma and spermatozoa than the subjects without varicocele. The degrees of varicocele and DNA damage were associated with decreased semen quality in infertile men with varicocele.