Role In Male Infertility Research Articles

Paying the price for standing tall: Fluid mechanics of prostate pathology.

BackgroundAge‐dependent increase in the incidence of benign prostatic hyperplasia (BPH) and prostate cancer (PCa) are both related to cell proliferation and survival controlled by intraprostatic free testosterone (FT) concentration. Paradoxically, BPH and PCa occur as circulating testosterone levels decrease, so any possible relationship between testosterone levels and development of BPH and PCa remains obscure.ResultsIn BPH the enlarging prostate is exposed to high testosterone levels arriving directly from the testes at concentrations about hundredfold higher than systemic FT. This occurs because venous blood from the testes is diverted into the prostate due to the elevated hydrostatic pressure of blood in the internal spermatic veins (ISVs). Elevated pressure is caused by the destruction of one‐way valves (clinically detected as varicocele), a unique phenomenon related to human erect posture. While standing, human males are ISVs vertically oriented, resulting in high intraluminal hydrostatic pressures—a phenomenon not found in quadrupeds. In this communication, we demonstrate the fluid mechanics' phenomena at the basis of varicocele leading to prostate pathology.ConclusionsSo far, varicocele has been studied mostly for its etiologic role in male infertility and, thus, for its effects on the testes. It is becoming clear that varicocele is a major etiologic factor in BPH and likely also in PCa. Restoring normal testicular venous pressure by treatment of the abnormal ISV's in varicocele has been shown to avert the flow from the prostate with the effect of reducing prostate volume, alleviating symptoms of BPH, and increasing concentrations of circulating FT.

Gut microbiota: an overlooked factor that plays a significant role in male infertility

共生的肠道菌群被称为人体第二个基因库，在不同时期呈现不同结构和功能特点。肠道菌群失调及其代谢产物的紊乱会影响人体能量代谢、免疫调节和消化吸收等生理过程，进而影响宿主性腺功能。最近研究发现肠道菌群失衡与男性不育有直接关系，但这一因素在临床上常被忽略。本文简要介绍了成年男性肠道菌群和精子形成的过程，以及肠道菌群通过介导内毒素血症、炎症反应，下调精子生成相关基因表达影响生精的潜在机制。这不仅为研究男性不育症发生机制开辟了新的领域，而且为此前所谓的病因不明的特发性男性不育症的临床诊治提供了新的方向和选择。.

In-vitro Antimicrobial Effect of Silybum marianum Extract on Bacterial Isolates from the Semen of Infertile Men in Iran

Background: Genital tract infection is one of the main causes of male infertility. The increasing frequency of drug resistance and side effects of antibiotics have urged researchers to seek alternative sources of antimicrobial agents, such as medicinal herbs, for the treatment of antibiotic-resistant infections. Objectives: The present study aimed to determine the frequency of potentially pathogenic microorganisms in the semen of infertile men and investigate the antimicrobial activity of Silybum marianum extract against the isolates. Methods: Semen samples were collected from 96 infertile men who referred to the Pasteur Laboratory in Gorgan, Iran. Semen samples were first analyzed according to the World Health Organization guidelines and then underwent microbiological tests to identify pathogens. Antimicrobial susceptibility to S. marianum extract was evaluated using the disk diffusion (Kirby-Bauer) method. Moreover, the active components of the extract were identified by the gas chromatography-mass spectrometry technique. Results: In the semen analysis, 64% of the samples had problems in the parameters of sperm count, motility, and morphology. In addition, the bacterial contamination was observed in 36% of semen samples. The most and the least common isolates were Staphylococcus aureus (45%) and Klebsiella pneumoniae (11%) and Staphylococcus epidermidis (11%), respectively. In Gram-positive isolates, S. aureus was mostly resistant to azithromycin (57%). In Gram-negative isolates, Escherichia coli was mostly resistant to gentamicin (37%). The inhibitory activity of S. marianum flower extract was significantly higher than that of S. marianum leaf extract (P < 0.01). Silybin (2.64%) and silychristin (3.07%) were the most abundant constituents of S. marianum flower extract. Conclusions: Bacterial infections play an important role in male infertility and S. marianum extract after purification can be potentially used for the treatment of antibiotic-resistant genital tract infections.

Future diagnostics in male infertility: genomics, epigenetics, metabolomics and proteomics.

A male factor is involved in 50% of couples with infertility. Unfortunately, the etiology of male factor infertility remains classified as idiopathic in nearly 50% of cases. The semen analysis (SA) continues to be first line for the workup of male infertility, but it is an imperfect test with high variability between samples. This lack of diagnostic capability has led to the desire to develop minimally invasive tests to aid with understanding the etiology of male factor infertility. Genetic factors are known to play a role in male infertility, and much work has been done to identify the many genes involved. The study of the genes involved, the impact of epigenetic modifications, proteins and metabolites produced are attractive targets for development of biomarkers which may be used to diagnose the etiology of male infertility. This review aims to explore recent advances in these fields as they pertain to the diagnosis of male infertility.

An Update on COVID19 from Etiopathogenesis, to Role in Male Infertility, Pregnancy Lactation and Regarding Treatment

An Update on COVID19 from Etiopathogenesis, to Role in Male Infertility, Pregnancy Lactation and Regarding Treatment

Oxidative stress in seminal plasma and its relation to fertility potential of human male subjects

Background: There is growing evidence that damage to spermatozoa by reactive oxygen species (ROS) plays a key role in male infertility. Human spermatozoa are susceptible to ROS as their plasma membrane contains abundant polyunsaturated fatty acid which can undergo lipid peroxidation which may cause damage to the sperms. Lipid peroxidation of sperm membrane is an important mechanism of this ROS-induced sperm damage leading to infertility. The present study was undertaken using malondialdehyde (MDA) for assessing oxidative stress which is an end product of lipid peroxidation. Aim and Objectives: The aim of this study was to evaluate the oxidative stress by estimating MDA (marker of lipid peroxidation) in seminal plasma of different groups of individuals and to correlate the levels with different seminogram parameters. Materials and Methods: Semen samples were obtained and analyzed for routine seminogram parameters from 150 male partners between ages 20 and 58 years of infertile couples attending reproductive biology unit. The patients were grouped into abnormal ejaculate (asthenoteratozoospermic ORIGINAL ARTICLE, oligoasthenoteratozoospermic, and azoospermic) and normal ejaculate groups. Oxidative stress was measured spectrophotometrically by estimating MDA. Results: Higher MDA levels of seminal plasma were observed in the AT and azoospermic groups as compared to normozoospermics though the difference was not statistically different. A significant rise in MDA levels was observed in the oligoasthenoteratozoospermic group. Seminogram parameters were found to be negatively correlated with seminal MDA level. Conclusion: Increased seminal plasma lipid peroxidation is likely to have an association with poor semen quality. Hence, MDA may be used as one of the biomarkers for assessing oxidative stress on sperm.

Association study of MTHFR-c677t with male infertility and reporting new potential SNPS/ sequence variants as a sourse of population genetic markers

It is estimated that about 15% of couples concern with the inability to conceive after 1 year of unprotected intercourse. Genetic and environmental factors play important roles in male infertility. MTHFR (Methylene Tetrahydro Folate Reductase) is encoded by a gene which maps to human chromosome 1p36.22. The c.677C>T mutation causes an amino - acid change of Alanine to Valine (Ala222Val) in exon 4 which is related to oligospermia and azoospermia. Our purpose was to investigate the association of rs1801133 in MTHFR gene with azoospermia and also genetic diversity of some Iranian folks. Peripheral blood samples of 100 men suffered from azoospermia and 55 controls collected from Infertility Clinic of Jihad-university of Qom. DNA was extracted by salting-out method and SNP-Genotyping was performed by PCR-RFLP technique and sequencing. Furthermore, statistical and population genetics analysis were done. The rs1801133 showed no significant relation with azoospermia according to statistical analysis. Furthermore, population genetics analysis showed that there is no genetic differentiation between Turk and Fars ethnics and case and control individuals. MTHFR studied SNP has no significant relation with azoospermia infertility, although further studies on more samples are demanded.

Long-term NaHS administration reduces oxidative stress and apoptosis in a rat model of left-side varicocele.

The main aim of this study was to assay the testicular H2 S levels in the varicocele rat model and then to investigate the protective effects of NaHS on morphometric changes, sperm parameters, oxidative stress and apoptosis markers in rat's testis. D,L-propargylglycine (PAG) was administrated to show the effects of cystathionine γ-lyase enzyme (CSE) inhibition in the varicocele. Rats were assigned to four groups: (a) Sham, (b) varicocele, (c) varicocele+PAG and (d) varicocele+NaHS. Animals in varicocele+NaHS group received 30µmol/L NaHS in drinking water for 56days. In the varicocele+PAG group, animals received PAG 19mg/kg twice a week. Morphometric assessment, oxidative stress markers, testicular H2 S levels, sperm parameters, TUNEL assay and expression of Bax/Bcl2 were evaluated at the end of experiment. Testicular H2 S levels were significantly decreased in varicocele group. NaHS significantly improved sperm parameters, morphometric characteristics and oxidative stress compared to varicocele group. Oxidative stress status deteriorated in the PAG group compared to the varicocele group. This study showed that a low testicular H2 S level might play a critical role in male infertility. Thus, NaHS administration may be a promising treatment strategy for male infertility in varicocele. In addition, CSE may not be the only important enzyme in testicular H2 S production.

EFFECT OF TOBACCO CHEWING ON SEMINAL PARAMETERS IN MALE PARTNERS OF INFERTILE COUPLES

Background: Male factors contribute to almost 50% of infertile couples. Deleterious effects of tobacco smoking on male reproductive system are well known. Research studies report contradictory findings about the effect of tobacco chewing on male fertility. Aim and objectives: To study effect of tobacco chewing on seminal parameters in male partners of infertile couples. Material and Methods: Present study was conducted on 100 male partners of infertile couples (50 tobacco chewers and 50 non-chewers) in age group of 21-40 years in the semen analysis laboratory in department of Physiology of Government Medical College, Nagpur from October 2014 to March 2016. Seminal parameters like volume of ejaculate, sperm count, sperm motility and motile sperm count were measured and compared in both groups. Result: Tobacco chewers had significantly lower values of all the seminal parameters as compared to non-chewers. Significantly low values of all parameters were observed in severe tobacco chewers as compared to mild and moderate tobacco chewers. Conclusion: Tobacco chewing has adverse effect on seminal parameters of male partners of infertile couples thus proving its pronounced role in male infertility. Severity of this effect increases as duration of tobacco chewing is prolonged.

EFFECT OF TOBACCO CHEWING ON SEMINAL PARAMETERS IN MALE PARTNERS OF INFERTILE COUPLES.

Background: Male factors contribute to almost 50% of infertile couples. Deleterious effects of tobacco smoking on male reproductive system are well known. Research studies report contradictory findings about the effect of tobacco chewing on male fertility. Aim and objectives: To study effect of tobacco chewing on seminal parameters in male partners of infertile couples. Material and Methods: Present study was conducted on 100 male partners of infertile couples (50 tobacco chewers and 50 non-chewers) in age group of 21-40 years in the semen analysis laboratory in department of Physiology of Government Medical College, Nagpur from October 2014 to March 2016. Seminal parameters like volume of ejaculate, sperm count, sperm motility and motile sperm count were measured and compared in both groups. Result: Tobacco chewers had significantly lower values of all the seminal parameters as compared to non-chewers. Significantly low values of all parameters were observed in severe tobacco chewers as compared to mild and moderate tobacco chewers. Conclusion: Tobacco chewing has adverse effect on seminal parameters of male partners of infertile couples thus proving its pronounced role in male infertility. Severity of this effect increases as duration of tobacco chewing is prolonged.

Expression of testicular phosphorylated proteins in types 1 and 2 diabetes mellitus in mice: An experimental study.

BackgroundTypes 1 and 2 diabetes mellitus (DM) are known to be the cause of sub/infertility. However, the comparisons of potential markers in spermatogenesis and steroidogenesis in DM males have never been elucidated.ObjectiveThis study aimed to examine the expressions of tyrosine-phosphorylated and steroidogenic acute regulatory (StAR) proteins in testis of DM mice.Materials and MethodsFifty-six male C57BL/6 mice were divided into four groups (n░=░14/ each): control of MLD-STZ (multiple low doses of streptozotocin), MLD-STZ, control of HFD-STZ (high-fat diet with STZ), and HFD-STZ. MLD-STZ mice (type 1 DM) were intraperitoneally (i.p.) injected with STZ at 40░mg/kg BW for five days. HFD-STZ mice (type 2 DM) received an HFD for 14 days and i.p.-induced by STZ at 85░mg/kg BW and fed with HFD. At the end of the experiment (days 36 and 72), the expressions of phosphorylated proteins and StAR were examined.ResultsTyrosine phosphorylated proteins were localized in late spermatids, luminal fluid, and Leydig cells. The intensities of phosphorylated 110, 85, 72, 60, and 55░kDas were lower in the 36 day-DM mice. Although such intensities were present in both groups, only 85░kDa in the MLD-STZ mice was higher in HFD mice at 72 days. StAR expressions in both groups were decreased than that of the controls.ConclusionDecreased expressions of StAR and tyrosine-phosphorylated proteins may be directly involved in low testosterone levels and impaired spermatogenesis. These findings support the notion that both DM types play a role in male infertility.

Antioxidant defence system in protein fractions of common carp (Cyprinus carpio) seminal plasma

There are growing evidences that the damage which is caused to the spermatozoa by the reactive oxygen species (ROS) plays a key role in male infertility. The seminal plasma is endowed with many enzymatic and non-enzymatic antioxidants which protect the spermatozoa against oxidative stress. The present study was undertaken to compare the level of superoxide dismutase (SOD), glutathione reductase (GR) and glutathione peroxidase (GPx) in separated protein fractions of whole common carp Cyprinus carpio seminal plasma. Seminal plasma from six male common carp was separated into four fractions. The fractions differed from each other in their total seminal plasma protein content and antioxidant status. The highest value of SOD (2.81 ± 0.11 mU/mg protein) was found in fraction 4, and the lowest (1.83 ± 0.18 mU/mg protein) in fraction 1. There were significant variations (ANOVA; P = 0.05) in GR activity, mainly between fractions 1, 2, and 4. The lowest value of GPx activity (14.9 ± 0.4 mU/mg protein) was found in fraction 2; however, the GPx activity showed low variability among fractions. We conclude that distinct seminal plasma fractions differ in antioxidant capacity. The inclusion of fractions with high levels of SOD, GR, and GPx in sperm storage medium may enhance protection against oxidative stress and promote sperm survival during the in vitro storage.

The role of DEFB126 variation in male infertility and medically assisted reproduction technique outcome.

Human DEFB126 is an important component of the glycocalyx of human spermatozoa. Beta-defensins play a primary role in male infertility due to their involvement in maturation and capacitation of spermatozoa. A 2-nt deletion of DEFB126 affects sperm function and so this study investigated the possible association between DEFB126 variants and its protein expression on medically assisted reproduction (MAR) technique outcome in Iranian infertile males. The presence of a 2-nt deletion of DEFB126, and its protein expression in spermatozoa, were investigated by standard polymerase chain reaction (PCR) sequencing and immunocytochemistry, respectively. MAR technique outcome according to clinical pregnancy rates was assessed in 277 Iranian males with unexplained infertility, including 139 patients who underwent intrauterine insemination (IUI) and 103 patients who underwent IVF/intracytoplasmic sperm injection (ICSI), as well as 35 infertile males who declined to use any MAR treatment. As the control group, 100 fertile males with a normal spermiogram were enrolled. The 2-nt deletion of DEFB126 was significantly higher in infertile patients than controls (P≤0.05). The presence of this deletion resulted in significantly lower clinical pregnancy rates following IUI (P≤0.05); however, there were no differences in IVF/ICSI outcomes according to genotype. The protein expression in del/del males was also remarkably lower than that of the other genotypes. This sequence variation of DEFB126 may impair male reproductive function and can be related to male infertility. Interestingly, males with the del/del genotype have a normal spermiogram; however, their spermatozoa are evidently functionally impaired, which can affect IUI treatment outcome, but not treatment by IVF/ICSI.

Chloride Channel Accessory 4 (CLCA4) Gene Polymorphisms and Non-Obstructive Azoospermia: A Case-Control Study.

BackgroundGenetic mechanisms are associated with male infertility, but the association with non-obstructive azoospermia (NOA) remains unclear. Mutations in the chloride channel accessory 4 (CLCA4) gene have been shown to have a role in male infertility. The aim of this study was to investigate the associations between single nucleotide polymorphisms (SNPs) of the CLCA4 gene and NOA in a Chinese Han population of Northeast China using combined targeted gene capture next-generation sequencing and bioinformatics analysis.Material/MethodsThe study group included 100 men with NOA, and there were 100 normal controls. Targeted gene capture next-generation sequencing was performed combined with bioinformatics analysis. Ten CLCA4 SNPs were screened in the cases of NOA and control subjects. The associations between SNPs and NOA were analyzed.ResultsSix SNPs, c.390C>T (rs190628533), c.1474A>G (rs2231599), c.2105C>G (rs757773924), c.2371A>T) (rs759981524), c.956G>A (rs763334876), and c.895T>C (rs79822589) were identified in the study group of cases in NOA but not in control subjects. All CLCA4 SNPs were in Hardy-Weinberg equilibrium. The allele and genotype frequencies of the six SNPs were not significantly different between the study group and the controls. Haplotype analysis showed the existence of two haplotypes, CTAGACTACG and CTCGACTACG, which showed statistical significance of 0.074, and 0.088 between cases of NOA and the controls, respectively.ConclusionsThere were no significant associations between CLCA4 SNPs and NOA in men in a Chinese Han population of Northeast China.

Sperm Microbiota and Its Impact on Semen Parameters.

Compared to its female counterpart, the microbiota of the male genital tract has not been studied extensively. With this study, we aimed to evaluate the bacterial composition of seminal fluid and its impact on sperm parameters. We hypothesized that a dysbiotic microbiota composition may have an influence on sperm quality. Semen samples of 26 men with normal spermiogram and 68 men with at least one abnormal spermiogram parameter were included in the study. Samples were stratified based on total sperm count, spermatozoa concentration, progressive motility, total motility and spermatozoa morphology. Microbiota profiling was performed using 16S rRNA gene amplicons sequencing and total bacterial load was determined using a panbacterial quantitative PCR. Semen samples broadly clustered into three microbiota profiles: Prevotella-enriched, Lactobacillus-enriched, and polymicrobial. Prevotella-enriched samples had the highest bacterial load (p < 0.05). Network analysis identified three main co-occurrence modules, among which two contained bacteria commonly found in the vaginal flora. Genera from the same module displayed similar oxygen requirements, arguing for the presence of different ecological niches for bacteria that colonize semen through the passage. Contrary to our hypothesis, shifts in overall microbiota composition (beta-diversity) did not correlate with spermiogram parameters. Similarly, we did not find any difference in microbial richness or diversity (alpha-diversity). Differential abundance testing, however, revealed three specific genera that were significantly enriched or depleted in some of the sperm quality groups (p < 0.05). Prevotella relative abundance was increased in samples with defective sperm motility while Staphylococcus was increased in the corresponding control group. In addition, we observed an increased relative abundance of Lactobacillus in samples with normal sperm morphology. Our study indicates that overall bacterial content of sperm might not play a major role in male infertility. Although no major shifts in microbiota composition or diversity were found, the differential abundance of specific bacterial genera in the sperm suggests that a small subset of microbes might impact the spermatozoal physiology during sperm transition, more specifically motility and morphology. Further studies are required to challenge this finding and develop potential strategies to induce the formation of a healthy seminal microbiota.

MicroRNAs: Recent insights towards their role in male infertility and reproductive cancers.

Spermatogenesis is a tightly controlled, multi-step process in which mature spermatozoa are produced. Disruption of regulatory mechanisms in spermatogenesis can lead to male infertility, various diseases of male reproductive system, or even cancer. The spermatogenic impairment in infertile men can be associated with different etiologies, and the exact molecular mechanisms are yet to be determined. MicroRNAs (miRNAs) are a type of non-protein coding RNAs, about 22 nucleotides long, with an essential role in post-transcriptional regulation. miRNAs have been recognized as important regulators of various biological processes, including spermatogenesis. The aim of this review is to summarize the recent literature on the role of miRNAs in spermatogenesis, male infertility and reproductive cancers, and to evaluate their potential in diagnosis, prognosis and therapy of disease. Experimental evidence shows that aberrant expression of miRNAs affects spermatogenesis at multiple stages and in different cell types, most often resulting in infertility. In more severe cases, dysregulation of miRNAs leads to cancer. miRNAs have enormous potential to be used as diagnostic and prognostic markers as well as therapeutic targets in male infertility and reproductive system diseases. However, to exploit this potential fully, we need a better understanding of miRNA-mediated regulation of spermatogenesis, including the characterization of yet unidentified miRNAs and related regulatory mechanisms.

Evaluation of Periodontal Status among Men Undergoing Infertility Treatment.

Aims:It has been estimated that >30% of male infertility cases are of idiopathic etiology. Recent studies revealed a positive connection between periodontal pockets and sperm submotility, which proposes that periodontitis may have a role in male infertility and inadequate semen quality. The aim of the present investigation was to inspect the relationship between male fertility parameters and the periodontal status of male patients attending in vitro treatment (IVF) clinic.Materials and Methods:The study participants comprised 85 men going to the facility for sperm investigation before semen insemination. The nature of sperm was surveyed by the WHO 2010 criteria. On the same day, male patients were examined for periodontal parameters.Results:The patients were determined to have either gingivitis (24.7%) or periodontitis (75.3%). Normospermia was credited to 23.5% and oligozoospermia to 43.5%. Sperm submotility was seen in 76.4% of patients. A higher number of sites with clinical attachment loss showed a positive correlation with sperm submotility and sperm count.Conclusions:The findings of the present study showed a conceivable relationship between male infertility, decreased semen quality, and periodontal diseases in men visiting IVF centers. Periodontitis may subsequently play a role in male infertility.

25-Hydroxy cholecalciferol, anti-Müllerian hormone, and thyroid profiles among infertile men

Background and aim We examined the relationship among vit.D3, AMH, FT3, FT4, and TSH, in addition to the serum levels of reproductive hormones (FSH, LH, prolactin, and free testosterone), in oligoasthenoteratozoospermia and azoospermia patients in a cohort of infertile men from Egypt to establish a clinical marker/cause-effect relationship. Methods This cross-sectional cohort study was carried out on 301 men (105 males with oligoasthenoteratozoospermia and 96 males with azoospermia), in addition to 100 controls. Measurements of serum vit.D3, AMH, FT3, FT4, and TSH levels, in addition to reproductive hormone assays, were performed on all included subjects, using ELISA kits. Results Overall, results showed significantly lower serum levels of vit.D3 in infertile men than in the controls, with a greater decrease observed in men with azoospermia than in oligoasthenoteratozoospermia patients, (p < .05 for all). Significantly higher serum TSH and FSH levels and significantly lower serum free testosterone levels were observed in males with azoospermia than in males with oligoasthenoteratozoospermia and the controls (p < .05 for both). There were no significant differences between the studied groups in terms of AMH, FT3 or FT4 levels. LH levels were negatively correlated with TSH levels and positively correlated with AMH levels among men with oligoasthenoteratozoospermia, while among men with azoospermia, LH levels were positively correlated with vit.D3 levels (p < .05 for all). Conclusion Decreased Vit.D3 could play a role in male infertility, in addition to abnormal thyroid function, which needs further investigation.

Oxidative stress in sperm affects the epigenetic reprogramming in early embryonic development

BackgroundReactive oxygen species (ROS)-induced oxidative stress is well known to play a major role in male infertility. Sperm are sensitive to ROS damaging effects because as male germ cells form mature sperm they progressively lose the ability to repair DNA damage. However, how oxidative DNA lesions in sperm affect early embryonic development remains elusive.ResultsUsing cattle as model, we show that fertilization using sperm exposed to oxidative stress caused a major developmental arrest at the time of embryonic genome activation. The levels of DNA damage response did not directly correlate with the degree of developmental defects. The early cellular response for DNA damage, γH2AX, is already present at high levels in zygotes that progress normally in development and did not significantly increase at the paternal genome containing oxidative DNA lesions. Moreover, XRCC1, a factor implicated in the last step of base excision repair (BER) pathway, was recruited to the damaged paternal genome, indicating that the maternal BER machinery can repair these DNA lesions induced in sperm. Remarkably, the paternal genome with oxidative DNA lesions showed an impairment of zygotic active DNA demethylation, a process that previous studies linked to BER. Quantitative immunofluorescence analysis and ultrasensitive LC–MS-based measurements revealed that oxidative DNA lesions in sperm impair active DNA demethylation at paternal pronuclei, without affecting 5-hydroxymethylcytosine (5hmC), a 5-methylcytosine modification that has been implicated in paternal active DNA demethylation in mouse zygotes. Thus, other 5hmC-independent processes are implicated in active DNA demethylation in bovine embryos. The recruitment of XRCC1 to damaged paternal pronuclei indicates that oxidative DNA lesions drive BER to repair DNA at the expense of DNA demethylation. Finally, this study highlighted striking differences in DNA methylation dynamics between bovine and mouse zygotes that will facilitate the understanding of the dynamics of DNA methylation in early development.ConclusionsThe data demonstrate that oxidative stress in sperm has an impact not only on DNA integrity but also on the dynamics of epigenetic reprogramming, which may harm the paternal genetic and epigenetic contribution to the developing embryo and affect embryo development and embryo quality.

Male infertility: the intracellular bacterial hypothesis.

Infertility is a disease that affects one in seven couples. As male infertility affects approximately 30% of these couples with an unknown cause in half the cases, it represents a major public health concern. The classic treatment of male infertility involves intrauterine insemination, with modest outcome, and in vitro fertilization with intracytoplasmic sperm injection, which is known to be invasive and expensive, without treating the specific cause of infertility. Male fertility is mainly evaluated through a semen assessment where abnormal parameters such as concentration and motility can be associated with a decreased chance of conception. Infectious processes represent plausible candidates for male infertility. Chlamydia trachomatis is well known to cause female infertility through tubal damage but its role in male infertility remains controversial. The link between ureaplasmas/mycoplasmas and male infertility is also debatable. The potential negative impact of these bacteria on male fertility might not only involve semen parameters but also, as with C. trachomatis, include important physiological mechanisms such as fertilization processes that are not routinely assessed during infertility investigation. Basic research is important to help determine the exact effect of these bacteria on male fertility to develop targeted treatment and go beyond in vitro fertilization with intracytoplasmic sperm injection.