High Sperm DNA Damage Research Articles

Alpha-Lipoic Acid Ameliorates Sperm DNA Damage and Chromatin Integrity in Men with High DNA Damage: A Triple Blind Randomized Clinical Trial.

Evidence suggests the contributory role of oxidative stress (OS) to sperm DNA damage and eventually, male infertility. Antioxidant supplementation has exhibited favorable results regarding seminal OS, sperm DNA damage, and chromatin integrity. We aimed to evaluate the effect of alpha-lipoic acid (ALA) supplementation on semen analysis, sperm DNA damage, chromatin integrity, and seminal/intracellular OS in infertile men with high sperm DNA damage. In this randomized triple-blind placebo-controlled clinical trial study, we opted for a triple-blind controlled clinical trial design. Considering the study's inclusion criteria for the level of sperm DNA fragmentation (higher than the threshold of 30 and 15%), 70% of participants were selected for this clinical research study. Subjects were divided into case and control groups receiving oral ALA (600 mg/day) and placebo for eighty days, respectively. Sperm parameters and functional tests were examined and compared before and after treatment. The final sample size was 34 and 29 for ALA and placebo receivers, respectively. No significant differences were observed about anthropometrics and baseline measures of semen analysis, DNA damage, OS, and chromatin integrity between the two groups. Conventional semen parameters were enhanced insignificantly in both groups (P>0.05). DNA damage decreased significantly in the ALA group, as per sperm chromatin structure assay (SCSA, P<0.001). Moreover, chromomycin A3 (CMA3) staining results indicated a decrease in nuclear protamine deficiency post-ALA therapy (P=0.004). Lipid peroxidation decreased significantly after treatment with ALA (P=0.003). Further, seminal antioxidant capacity/activity did not differ significantly in either of the groups (registration number: IRCT20190406043177N1). An 80-day course of oral ALA supplementation (600 mg/day) alleviates sperm OS, DNA damage, and chromatin integrity in men with high sperm DNA damage.

Severe Oligospermia Treatment with Testicular Sperm Using “ICSI”

Introduction: Assisted reproductive technology has been developed significantly throughout the past few years, particularly diagnosing and treating male infertility. Many studies have been performed showing that Intracytoplasmic Sperm Injection (ICSI) is a successful method to attain clinical pregnancy and live birth through impaired spermatozoa characteristics or low sperm count, such as severe oligospermia. Severe oligospermia indicates low sperm count, which in some cases leads to azoospermia. Severe oligospermia can be caused by several factors such as genetics or medication. In search of efficient treatment for couples with Severe oligospermia, numerous retrospective and prospective researches have reported high pregnancy and live birth rates through testicular sperm for men with severe oligospermia and cryptozoospermia with or without high sperm DNA damage. The research showed that the use of testicular sperm in combination with ICSI yielded a high pregnancy rate and live births over another source of sperm, such as ejaculated sperms. Moreover, the use of ICSI in severe oligospermia has shown successful fertilization and pregnancy.&#x0D; Methods: In search for effective treatment for couples with severe male factor, a number of small retrospective and prospective studies have reported high pregnancy and live birth rates using testicular sperm for men with necrozoospermia, cryptozoospermia and oligozoospermia with or without elevated sperm DNA damage. Although the data suggest that there may be some benefit in performing testicular sperm retrieval (TSR)-ICSI in select groups of non-azoospermic infertile men, there are potential risks involved with TSR. Clinicians should balance these risks prior to the recommendation of TSR-ICSI on the result of a semen analysis or sperm DNA test alone. Careful evaluation and management of male factor infertility is important. The use of TSR-ICSI in the absence of specific sperm DNA defects is still experimental.&#x0D; Discussion: In 1992 and subsequently, several reports indicated that ICSI was a successful technique to achieve clinical pregnancy and live birth using spermatozoa with severely impaired characteristics. The initial optimism over the ability of ICSI to overcome significant sperm abnormalities was later tempered by the findings of more recent publications suggesting that some sperm deficits may not be as effectively treated with ICSI.&#x0D; Conclusion: Severe oligospermia indicates low sperm count, which can lead to male infertility; severe oligospermia which can be overcome through ICSI. Genetic factors like microdeletions of the Y chromosome (Yq) can cause severe oligospermia or chemotherapy molecules, affecting the sperm count directly.

DNA repair and response to sperm DNA damage in oocytes and embryos, and the potential consequences in ART: a systematic review.

Sperm DNA damage is considered a predictive factor for the clinical outcomes of patients undergoing ART. Laboratory evidence suggests that zygotes and developing embryos have adopted specific response and repair mechanisms to repair DNA damage of paternal origin. We have conducted a systematic review in accordance with guidelines from Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) to identify and review the maternal mechanisms used to respond and repair sperm DNA damage during early embryonic development, how these mechanisms operate and their potential clinical implications. The literature search was conducted in Ovid MEDLINE and Embase databases until May 2021. Out of 6297 articles initially identified, 36 studies were found to be relevant through cross referencing and were fully extracted. The collective evidence in human and animal models indicate that the early embryo has the capacity to repair DNA damage within sperm by activating maternally driven mechanisms throughout embryonic development. However, this capacity is limited and likely declines with age. The link between age and decreased DNA repair capacity could explain decreased oocyte quality in older women, poor reproductive outcomes in idiopathic cases and patients who present high sperm DNA damage. Ultimately, further understanding mechanisms underlying the maternal repair of sperm DNA damage could lead to the development of targeted therapies to decrease sperm DNA damage, improved oocyte quality to combat incoming DNA insults or lead to development of methodologies to identify individual spermatozoa without DNA damage.

Relationship between functional Nrf2 gene promoter polymorphism and sperm DNA damage in male infertility

ABSTRACT This study examines the association of the −617 C > A polymorphism in the Nrf2 gene (rs6721961) with male infertility in a Turkish population and determines its functional role in spermatogenesis in correlation with the impact of different levels of DNA damage on the genotypes. A total of 100 infertile men and 100 healthy fertile men were included in the study. Nrf2 genotyping was performed with the PCR-based restriction fragment length gene polymorphism (RFLP-PCR) analysis. According to our results, the Nrf2 CC, CA, and AA genotype distribution frequencies were 58.6%, 38.4%, and 3% in the control group, respectively, and 38%, 48%, and 14% in the infertile men, respectively. The AA genotype was significantly higher in the patient group. In smokers, a significant difference was found in progressive motility values between the genotypes (p = 0.001). Also, sperm progressive motility and concentration decreased significantly in those smokers with the AA genotype; smokers carrying this genotype were also 5.75 times more likely to have oligoasthenozoospermia than those with CC (p < 0.05). There was a significant relationship between the number of cases with high sperm-DNA damage when comparing the frequency of Nrf2 AA genotype carriers with the CC genotype 16.3% vs. 6.9%, respectively (p < 0.001). These results suggest the importance of the Nrf2 gene C > A (rs 6,721,961) polymorphism in the etiology of sperm DNA damage as a risk factor for male infertility. Smokers carrying the AA genotype are more likely to impair seminal parameters through antioxidant mechanisms. Abbreviations: Polymerase chain reaction (PCR)-based restriction fragment length gene polymorphism (RFLP-PCR); reactive oxygen species (ROS); deoxyribonucleic acid (DNA); catalases (CATs); superoxide dismutase (SOD); glutathione peroxidase (GPX); glutathione-S-transferase (GST); Nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2); basic leucine zipper (bZIP); antioxidant response element (ARE); World Health Organization (WHO);normospermia(NS);asthenozoospermia(AS);oligozoospermia(OS);oligoasthenozoospermia (OAS); follicle stimulating hormone (FSH); ultraviolet (UV); low-melting-point agarose (LMA); normal-melting-point agarose (NMA); arbitrary units (AU); total comet score (TCS); A one-way analysis of variance (ANOVA); standard deviation (SD); N-acetyltransferase (NAT2); small non-coding RNAs (ncRNAs); microRNAs (miRNA)

SPERM DNA FRAGMENTATION AND FUNCTIONAL FEATURES OF HUMAN SPERM SELECTED BY MICROFLUIDIC SORTING FOR CLINICAL USE

High sperm DNA damage is associated with decreased normal fertilization, embryo development and pregnancy rates, and an increased miscarriage rate. Thus, selecting sperm with minimal DNA damage is important for assisted reproductive technology. A microfluidic sperm selection chamber (MSS, ZyMōt™; DxNow) is a device designed to collect sperm with high motility and chromatin integrity, which has recently been clinically used for ICSI/IVF. Here we aimed to comprehensively evaluate MSS compared to density-gradient centrifugation (DGC) in terms of (1) sperm DNA fragmentation by sperm chromatin dispersion (SCD) test and comet assay, (2) sperm motility and morphological features of motile sperm, and (3) blastocyst development after ICSI and clinical outcomes after vitrified-thawed single blastocyst transfers (vSBT). Sperm analysis was performed in 23 cases between October 2020 and February 2021. SCD test was optimized as a rapid procedure (≤30 min), with sperm showing a halo deemed normal, and those without a halo abnormal. Comet assay results were analyzed using CometScore 2.0, with comparison of %Tail DNA, Tail Length (TL), and Tail Moment (TM). Sperm motility parameters were investigated using the Sperm Motility Analysis System (SMAS, Dietect). To assess motile spermatozoa characteristics, middle piece morphology and active mitochondrial distribution were labeled by MitoTracker-Red. The reactive oxygen species (ROS) level was labeled using CM-H2DCFDA. ICSI outcomes (normal fertilization, blastocyst development, and pregnancy rates) were compared between DGC and MSS for 620 cycles between September 2019 and December 2020. In SCD test, MSS yielded a significantly lower abnormality rate than for raw sperm and DGC in all cases. The comet assay showed that %Tail DNA, TL, and TM were significantly lower with MSS than for raw sperm or DGC. Sperm motility rates were significantly higher with DGC and MSS than for raw sperm. Sperm motility analysis demonstrated significantly lower straightness, linearity, and beat-cross frequency (Hz) with MSS compared to DGC. The morphological abnormality rate of the sperm midpiece was significantly higher with MSS than DGC. Abnormal sperm midpieces exhibited significantly high ROS activity around mitochondria. Fertilization after ICSI and blastocyst rates were similar between MSS and DGC, while the vitrified blastocyst rate was significantly higher with MSS than DGC. Clinical pregnancy and miscarriage rates after vSBT did not significantly different between MSS and DGC. MSS-selected sperm had high DNA integrity and were homogeneous. The sperm had a higher motility rate, but the characteristic sperm motility pattern was meandering motion. Additionally, MSS did not exclude sperm that were morphologically abnormal in the middle piece with high ROS levels. MSS-ICSI yielded an improved vitrified blastocyst rate, and MSS is an effective device for sperm collection for ICSI.

Green tea extract as a cryoprotectant additive to preserve the motility and DNA integrity of human spermatozoa.

Cryopreservation impairs sperm quality and functions, including motility and DNA integrity. Antioxidant additives in sperm freezing media have previously brought improvements in postthawed sperm quality. Green tea extract (GTE) is widely considered as an excellent antioxidant, and its beneficial role has been proven in other human cells. This study aims to evaluate the GTE as a potential additive in cryopreservation media of human spermatozoa. In part one, the semen of 20 normozoospermic men was used to optimize the concentration of GTE that maintains sperm motility and DNA integrity against oxidative stress, induced by hydrogen peroxide (H2O2). Spermatozoa were treated with GTE at different concentrations before incubation with H2O2. In part two, the semen of 45 patients was cryopreserved with or without 1.0 ng ml−1 GTE. After 2 weeks, the semen was thawed, and the effect on sperm motility and DNA fragmentation was observed. Our data showed that GTE significantly protected sperm motility and DNA integrity against oxidative stress induced by H2O2 when added at a final concentration of 1.0 ng ml−1. We found that the addition of 1.0 ng ml−1 GTE to cryopreservation media significantly increased sperm motility and DNA integrity (both P < 0.05). More interestingly, patients with high sperm DNA damage benefited similarly from the GTE supplementation. However, there was no significant change in the reactive oxygen species (ROS) level. In conclusion, supplementing sperm freezing media with GTE has a significant protective effect on human sperm motility and DNA integrity, which may be of clinical interest.

Sperm DNA fragmentation is a novel biomarker for early pregnancy loss

Research questionSpontaneous pregnancy loss affects 10–15% of couples, with 1–2% suffering recurrent pregnancy loss and 50% of miscarriages remaining unexplained. Male genomic integrity is essential for healthy offspring, meaning sperm DNA quality may be important in maintaining a pregnancy. Does sperm DNA fragmentation measured by alkaline Comet assay act as a biomarker for early pregnancy loss? DesignSperm DNA fragmentation was measured by alkaline Comet test in 76 fertile donors and 217 men whose partners had recently experienced miscarriage. Couples were divided into five groups for analysis: one miscarriage after spontaneous conception; two or more miscarriages after spontaneous conception; one miscarriage after fertility treatment; two or more miscarriages after fertility treatment and biochemical pregnancy. ResultsReceiver operator characteristic curve analysis was used to determine ability of the average Comet score (ACS), low Comet score (LCS) and high Comet score (HCS) to diagnose miscarriage and develop clinical thresholds comparing men whose partners have miscarried with men with recently proven fertility. Male partners of women who had miscarried had higher sperm DNA damage (ACS 33.32 ± 0.57%) than fertile men (ACS 14.87 ± 0.66%; P < 0.001). Average Comet score, HCS and LCS all have promise as being highly predictive of sporadic and recurrent miscarriage using clinical thresholds from comparisons with fertile men's spermatozoa: receiver operating characteristic curve AUC for ACS ≥26%, 0.965; LCS ≤70%, 0.969; HCS ≥2%, 0.883; P <0.0001. ConclusionsSperm DNA damage measured by the alkaline Comet has promise as a robust biomarker for sporadic and recurrent miscarriage after spontaneous or assisted conception, and may provide novel diagnoses and guidance for future fertility pathways.

The Use of Testicular Sperm for Intracytoplasmic Sperm Injection in Patients with High Sperm DNA Damage: A Systematic Review.

The advent of intracytoplasmic sperm injection (ICSI) has changed the human reproduction landscape by overcoming several limitations related to both male and female infertility factors. However, despite the development of new technologies, the live-birth rate with ICSI has not exceeded 30%. In order to improve assisted reproductive technology outcomes, advanced sperm function analysis have gained increased attention and the effects of sperm DNA fragmentation (SDF) on assisted reproduction success are being extensively studied. Utilizing ejaculated sperm with an elevated SDF has been found to result in poor ICSI outcomes. Furthermore, studies have reported that testicular sperm has lower SDF level, when compared to ejaculated sperm. This has led a number of clinicians world-wide to offer testicular sperm retrieval for ICSI in non-azoospermic males with high SDF. This practice has remained controversial due to lack of high quality evidence.

Age-related changes in human sperm DNA integrity.

Abnormal standard semen characteristics and reduced sperm chromatin maturity can appear with increasing male age. However, the influence of paternal age on semen parameters is still controversial. Therefore, this study was designed to estimate the influence of paternal age not only on conventional semen characteristics but also on sperm DNA integrity. This research was carried out on ejaculated sperm cells obtained from men (n = 1124) aged ≥40 y and <40 y. Our data revealed a decreased semen volume and an increased percentage of DFI (sperm DNA fragmentation index) in older men compared to younger men in the entire study cohort, in men with normozoospermia and in men with abnormal semen parameters. Moreover, there was a higher incidence of sperm DNA damage (>10% DFI, low fertility potential) in the groups of men aged ≥40 y than in the groups of men aged <40 y. Older men had over twice the odds ratio for high sperm DNA damage as younger men. Our findings suggest a detrimental effect of advanced paternal age on sperm chromatin integrity. The data show that the evaluation of sperm DNA has greater clinical utility than standard semen analysis in case of male fertility potential assessment.

Testicular spermatozoon is superior to ejaculated spermatozoon for intracytoplasmic sperm injection to achieve pregnancy in infertile males with high sperm DNA damage

The purpose of this study was to compare the clinical outcome of testicular spermatozoon versus ejaculated spermatozoon in the treatment of infertile males with high sperm DNA damage, referred as sperm DNA fragmentation index (DFI), that attending intracytoplasmic sperm injection (ICSI) programme in terms of clinical pregnancy, births delivered as the primary and pregnancy loss and embryo fertilisation as the secondary outcome. A total of 102 males fulfilling the inclusion criteria were enrolled in the present study. Of the 102 males, 61 infertile males underwent testicular spermatozoon combined with ICSI while the remaining 41 males applied ejaculated spermatozoa in their first ICSI cycles, and the data of them were collected and analysed. In a 18-month follow-up, testicular spermatozoon achieved higher pregnancy rate and deliver rate than those in ejaculated sperm group (pregnancy rate, 36% vs. 14.6%, p=0.017; deliver rate, 38.5% vs. 9.8%, p=0.001). Nevertheless, there were no significant differences in the number of oocytes aspirated and number of embryos transferred between the two groups. Additionally, the fertilisation rate in the testicular sperm study cohort (70.4%) was also similar to that in the ejaculated sperm group (75.0%). Based on the current data, we conclude that testicular spermatozoon is the prior option in the treatment of infertile males with high sperm DFI in ICSI programme. More high-quality studies with larger samples size are needed in the future due to the relative small size and the nonrandomized design of the present study.

Genetic Polymorphisms in PRM1, PRM2, and YBX2 Genes are Associated with Male Factor Infertility.

The etiology of infertility is still unknown in almost half of all male infertility patients. In sperm, DNA condensation differs from somatic and female gamete cells, with the protamine (PRM) gene and its transcription factor, Y-box binding protein 2 (YBX2), playing key roles in making the structure more compact. Protamine polymorphisms have been studied in different populations, but various results have been acquired. In our study, we examined, for the first time in a Turkish population, the association between protamine gene alleles (PRM1 c.-190C>A, PRM1 c.197G>T, and PRM2 c.248C>T), and YBX2 (c.187T>C and c.1095 + 16A>G) and male infertility. This was accomplished using polymerase chain reaction-restriction fragment length polymorphism analyses of 100 infertile and 100 fertile Turkish men. Sperm DNA fragmentation analysis was performed using the Comet technique. We found that the AA and CA genotypes of the PRM1 c.-190C>A polymorphism had a significant association with infertility (p < 0.001) and the AA genotype was also highly significantly associated with high sperm DNA damage (p < 0.001). This study demonstrates that the PRM1 c.-190C>A polymorphism is associated with sperm DNA fragmentation, which may impact male infertility in the Turkish population. Further research with larger groups and in various other study populations will be required to clarify the impact of protamine and YBX2 gene polymorphisms on male infertility.

Condensyl® and decreases sperm DNA damage which is a risk factor for male infertility: evaluation of a health claim pursuant to Article 14 of Regulation (EC) No 1924/2006

Following an application from Laboratoire Nurilia submitted for authorisation of a health claim pursuant to Article 14 of Regulation (EC) No 1924/2006 via the Competent Authority of France, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to ‘Condensyl® and decreases sperm DNA damage. High sperm DNA damage is a risk factor for male subfertility/infertility'. Condensyl® is a fixed combination of opuntia fruit dry extract, N‐acetyl cysteine, zinc, nicotinamide, vitamins B2, B6, B12 and E, and folic acid. The Panel considers that Condensyl® is sufficiently characterised. The Panel assumes that the disease that is the subject of the application is male infertility and that the target population for the claim includes males wishing to increase their fertility but excludes males with clinical infertility. The Panel considers that the reduction of DNA sperm damage is a beneficial physiological effect in the context of reducing the risk of male infertility. The applicant provided four human intervention studies conducted in males with clinical infertility, from which no conclusions could be drawn for the scientific substantiation of the claim. The Panel concludes that a cause and effect relationship has not been established between the consumption of Condensyl® and reduction of DNA sperm damage in the context of reducing the risk of male infertility.

Optimization of microelectrophoresis to select highly negatively charged sperm.

The sperm membrane undergoes extensive surface remodeling as it matures in the epididymis. During this process, the sperm is encapsulated in an extensive glycocalyx layer, which provides the membrane with its characteristic negative electrostatic charge. In this study, we develop a method of microelectrophoresis and standardize the protocol to isolate sperm with high negative membrane charge. Under an electric field, the percentage of positively charged sperm (PCS), negatively charged sperm (NCS), and neutrally charged sperm was determined for each ejaculate prior to and following density gradient centrifugation (DGC), and evaluated for sperm DNA damage, and histone retention. Subsequently, PCS, NCS, and neutrally charged sperm were selected using an ICSI needle and directly analyzed for DNA damage. When raw semen was analyzed using microelectrophoresis, 94% were NCS. In contrast, DGC completely or partially stripped the negative membrane charge from sperm resulting PCS and neutrally charged sperm, while the charged sperm populations are increased with an increase in electrophoretic current. Following DGC, high sperm DNA damage and abnormal histone retention were inversely correlated with percentage NCS and directly correlated with percentage PCS. NCS exhibited significantly lower DNA damage when compared with control (P < 0.05) and PCS (P < 0.05). When the charged sperm population was corrected for neutrally charged sperm, sperm DNA damage was strongly associated with NCS at a lower electrophoretic current. The results suggest that selection of NCS at lower current may be an important biomarker to select healthy sperm for assisted reproductive treatment.

Association of MDR1 C3435T and C1236T single nucleotide polymorphisms with male factor infertility.

Infertility affects 1 in 6 couples and approximately 1 in 25 men. Male factor infertility is a major cause of spermatogenic anomalies, the causes of which are largely unknown. Impaired repro-ductive functions in men might result from physiological, genetic, and/or environmental factors such as xenobiotics. The multi-drug re-sistance1 (MDR1) gene encodes a P-glycoprotein which has a role in the active transport of various substrates providing protection of somatic cells from potentially toxic substances, including xenobi-otics. MDR1 is highly expressed at the luminal surface of capillary endothelial cells, and is expressed in Leydig cells, testicular mac-rophages, and Sertoli cells. We performed genotype and haplotype analyses of MDR1 in 192 infertile and 102 fertile Turkish men for the genetic markers C1236T and C3435T, using polymerase chain reaction-restriction fragment length polymorphism analysis. In the overall population, correlations were analyzed in all genotype mod-els. We found that the C3435T polymorphism TT vs CT genotypes showed statistically significant differences in their association with infertility (P = 0.045), and that the CT genotype was associated with high sperm DNA damage (P = 0.02), suggesting that the CT genotype might be a susceptibility factor for infertility. Additionally, the T-T haplotype was significantly more frequent in the control group (13.2 vs 6.5%; odds ratio = 0.459, 95%CI = 0.259-0.814, P = 0.006). This study showed that MDR1 might have a role in male infertility. Fur-ther research in large cohorts with different populations is required to clarify the role of MDR in male fertility.

Sperm DNA Fragmentation in Saudi Infertile Men with Normal Standard Semen Parameters

Almost 15% of infertile males have normal semen parameters and DNA Fragmentation Index (DFI) could be reasonably a valued tool for fertility extrapolation than the conventional semen analysis. To the best of our knowledge, this is the first study to assess the prevalence of high DFI in Saudi infertile men with normal standard semen parameters in order to support the generalizability about sperm DFI as a marker of male infertility. A total of 79 infertile men with normal semen standards were identified (study group). Standard semen analysis and sperm chromatin dispersion were carried out. 33 men (41.8% of the whole study group) had a DFI ≥ 20%; with 19 men (24.1%) (95% CI: 14.67-33.53) had a 20% ≤ DFI<30%, and 14 men (17.7 %) (95% CI: 9.28-26.12) had a DFI ≥ 30%. The mean DFI was 21.14% (±10.26%) with a median of 18.12% [5.09-57.23]. Our findings showed that a considerable proportion of men with normal semen parameters had high sperm DNA damage levels. Thus, the DFI by sperm chromatin dispersion test is essential to explain causes of infertility in cases where semen analysis has not shown any deviation from the norms.

Whether sperm deoxyribonucleic acid fragmentation has an effect on pregnancy and miscarriage after in vitro fertilization/intracytoplasmic sperm injection: a systematic review and meta-analysis

To examine whether sperm DNA fragmentation has an effect on pregnancy and miscarriage after IVF and/or intracytoplasmic sperm injection (ICSI). Systematic review and meta-analysis. University-affiliated teaching hospital. Infertility patient(s). An exhaustive electronic literature search was conducted on MEDLINE, Google Scholar, and the Cochrane Library, from database inception to October 2013. We included clinical trials that examined the influence of sperm DNA damage on pregnancy and miscarriage of IVF/ICSI. The outcomes of interest were pregnancy rate and miscarriage rate. In the analysis of pregnancy, 16 cohort studies (3,106 couples) were included. Of these, 14 studies (2,756 couples, 965 pregnancies) that also mentioned miscarriage were identified in the analysis of miscarriage. Meta-analysis showed that high-level sperm DNA fragmentation has a detrimental effect on outcome of IVF/ICSI, with decreased pregnancy rate and increased miscarriage rate. The stratified analysis by type of procedure (IVF vs. ICSI) indicated that high sperm DNA damage was related to lower pregnancy rates in IVF but not in ICSI cycles, whereas it was associated with higher miscarriage rates in both IVF and ICSI cycles. The results indicate that assays detecting sperm DNA damage should be recommended to those suffering from recurrent failure to achieve pregnancy. Selection of sperm without DNA damage for use may improve the clinical outcome of ART. The data also provide a rationale for conducting further research aimed at evaluating the underlying mechanism(s) responsible for the detrimental effect of high sperm DNA fragmentation and the potential therapy.

Evaluation of potential protein biomarkers in patients with high sperm DNA damage

The laboratory evaluation of male infertility remains an essential area of research as 40-60% of infertility cases are attributable to male-related factors. Current sperm analysis methods add only partial information on sperm quality and fertility outcomes. The specific underlying cause of infertility in most cases is unknown, while a proportion of male infertility could be caused by molecular factors such as the absence or abnormal expression of some essential sperm proteins. The objective of this study was to screen for associations between sperm protein profiles and sperm concentration, motility, and DNA fragmentation index in patients undergoing fertility evaluation in a clinical setting. Based on those parameters, semen samples were categorized as either normal or abnormal. We screened 34 semen samples with various abnormal parameters and compared them to 24 normal control samples by using one dimensional (1-D) gel electrophoresis and mass-spectrometry. In this study, we anticipated to establish a normal sperm parameter profile which would be compared to abnormal sperm samples and reveal candidate proteins. Our preliminary results indicate that no normal uniform profile could be established, which affirms the complexity of male fertility and confirms the limitations of standard semen analysis. Four main protein groups were identified in correlation with abnormal DNA fragmentation and/or motility. The first group included sperm nuclear proteins such as the SPANX (sperm protein associated with the nucleus on the X chromosome) isoforms and several types of histones. The second group contained mitochondria-related functions and oxidative stress proteins including Mitochondrial Ferritin, Mitochondrial Single-Stranded DNA Binding Protein, and several isoforms of Peroxiredoxins. Two other protein groups were related to sperm motility such as microtubule-based flagellum and spindle microtubule as well as proteins related to the ubiquitin-proteasome pathway. Further research is required in order to characterize these potential biomarkers of male fertility potential.

Sperm DNA damage has a negative association with live-birth rates after IVF

Sperm DNA damage has a negative impact on pregnancy rates following assisted reproduction treatment (ART). The aim of the present study was to examine the relationship between sperm DNA fragmentation and live-birth rates after IVF and intracytoplasmic sperm injection (ICSI). The alkaline Comet assay was employed to measure sperm DNA fragmentation in native semen and in spermatozoa following density-gradient centrifugation in semen samples from 203 couples undergoing IVF and 136 couples undergoing ICSI. Men were divided into groups according to sperm DNA damage. Following IVF, couples with <25% sperm DNA fragmentation had a live-birth rate of 33%; in contrast, couples with >50% sperm DNA fragmentation had a much lower live-birth rate of 13%. Following ICSI, no significant differences in sperm DNA damage were found between any groups of patients. Sperm DNA damage was also associated with low live-birth rates following IVF in both men and couples with idiopathic infertility: 39% of couples and 41% of men with idiopathic infertility have high sperm DNA damage. Sperm DNA damage assessed by the Comet assay has a close inverse relationship with live-birth rates after IVF.Sperm DNA damage has a negative impact on assisted reproduction treatment outcome, in particular, on pregnancy rates. The aim of the present study was to examine the relationship between sperm DNA fragmentation and live-birth rates after IVF and intracytoplasmic sperm injection (ICSI). The alkaline Comet assay was employed to measure sperm DNA fragmentation in native semen and in spermatozoa following density-gradient centrifugation in semen samples from 203 couples undergoing IVF and 136 couples undergoing ICSI. Men were divided into groups according to sperm DNA damage and treatment outcome. Following IVF, couples with <25% sperm DNA fragmentation had a live birth rate of 33%. In contrast, couples with >50% sperm DNA fragmentation had a much lower live-birth rate of 13% following IVF. Following ICSI, there were no significant differences in levels of sperm DNA damage between any groups of patients. Sperm DNA damage was also associated with the very low live-birth rates following IVF in both men and couples with idiopathic infertility: 39% of couples and 41% of men have high level of sperm DNA damage. Sperm DNA damage assessed by the Comet assay has a close inverse relationship with live-birth rates after IVF.

A comparison of ejaculated and testicular spermatozoa aneuploidy rates in patients with high sperm DNA damage

Testicular spermatozoa are utilized to achieve pregnancy in couples with severe male factor infertility. Several studies suggest that aneuploidy rates in spermatozoa are elevated at the testicular level in infertile patients compared to ejaculates of normal controls. However, essential data regarding aneuploidy rates between ejaculated and testicular spermatozoa in the same individuals is lacking. The purpose of our study was to compare aneuploidy rates at the testicular and post-testicular level from the same patients with persistently high sperm DNA damage. Ejaculates and testicular biopsies were obtained from eight patients with persistently high DNA damage (>30%). Both ejaculated and testicular samples were analyzed for sperm DNA damage and sperm aneuploidy for chromosomes 13, 18, 21, X, and Y. In addition, semen samples from ten normozoospermic men presenting for fertility evaluation served as a control group. A strong correlation between the alteration of spermatogenesis and chromatin deterioration was observed in our study. In the same individuals, testicular samples showed a significantly lower DNA damage compared to ejaculated spermatozoa (14.9% ± 5.0 vs. 40.6% ± 14.8, P < 0.05), but significantly higher aneuploidy rates for the five analyzed chromosomes (12.41% ± 3.7 vs. 5.77% ± 1.2, P < 0.05). While testicular spermatozoa appear favourable for ICSI in terms of lower DNA damage, this potential advantage could be offset by the higher aneuploidy rates in testicular spermatozoa.

Aneuploidy rates in ejaculated and testicular spermatozoa in patients with high sperm dna damage

OBJECTIVE: Testicular spermatozoa are commonly used to achieve pregnancy in couples with severe male factor infertility as the pregnancy rates with this procedure are comparable to procedures using ejaculated spermatozoa. Although several studies have suggested elevated aneuploidy rates in testicular samples in these patients compared to fertile controls, there is no data comparing aneuploidy rates in ejaculated and testicular spermatozoa in the same individual.