Sperm chromatin structure assay as an independent predictor of fertility in vivo: a case-control study

Sperm DNA Fragmentation in Male Infertility: Tests, Mechanisms, Meaning and Sperm Population to Be Tested

Sperm DNA fragmentation (sDF) is a DNA damage able to predict natural conception. Thus, many laboratories added tests for the detection of sDF as an adjunct to routine semen analysis with specific indications. However, some points related to sDF are still open. The available tests are very different each from other, and a direct comparison, in terms of the prediction of reproductive outcomes, is mandatory. The proposed mechanisms responsible for sDF generation have not yielded treatments for men with high levels of sDF that have gained the general consent in clinical practice, thus requiring further research. Another relevant point is the biological meaning to attribute to sDF and, thus, what we can expect from tests detecting sDF for the diagnosis of male infertility. SDF can represent the "tip of iceberg" of a more extended and undetected sperm abnormality somehow impacting upon reproduction. Investigating the nature of such a sperm abnormality might provide novel insights into the link between sDF and reproduction. Finally, several studies reported an impact of native sDF on assisted reproduction technique outcomes. However, to fertilise the oocyte, selected spermatozoa are used where sDF, if present, associates with highly motile spermatozoa, which is the opposite situation to native semen, where most sDF associates with non-viable spermatozoa. Studies comparing the impact of sDF, as assessed in both native and selected spermatozoa, are needed.

The paternal clock: Uncovering the consequences of advanced paternal age on sperm DNA fragmentation

The objective of the study was to investigate the relationship between advanced paternal age and sperm DNA fragmentation (SDF) levels, specifically identifying the age at which a significant increase in SDF occurs. This is a retrospective cohort study involving 4250 consecutive semen samples from patients presenting for infertility evaluation. Patients were stratified into seven age groups: < 26 (n = 36; 0.8 %), 26-30 (n = 500; 11.8 %), 31-35 (n = 1269; 29.9 %), 36-40 (n = 1268; 29.8 %), 41-45 (n = 732; 17.2 %), 46-50 (n = 304; 7.2 %), > 50 (n = 141; 3.3 %). The main outcome measures included comparing mean SDF levels throughout different age groups and assessing the prevalence of normal, intermediate, and high SDF among the age groups. A positive correlation was observed between paternal age and SDF (r = 0.17, p < 0.001). SDF remained relatively constant until the age of 35 but increased significantly beyond age 35. Mean SDF levels in the older age groups (36-40, 41-45, 46-50, and >50 years) were significantly higher than in the younger age groups (<26, 26-30, and 31-35 years) (p < 0.001). The prevalence of normal SDF was highest among the younger age groups, whereas the prevalence of high SDF was highest among the older age groups. Interestingly, the prevalence of intermediate SDF was relatively constant throughout the age groups (ranging between 29.8 % to 37.2 %). The increase in SDF after the age of 35 highlights the importance of considering male age in infertility evaluations. Assessing SDF in men over the age of 35 is crucial in couples seeking to conceive.

Epigenetic aging of mammalian gametes

The process of aging refers to physiological changes that occur to an organism as time progresses and involves changes to DNA, proteins, metabolism, cells, and organs. Like the rest of the cells in the body, gametes age, and it is well established that there is a decline in reproductive capabilities in females and males with aging. One of the major pathways known to be involved in aging is epigenetic changes. The epigenome is the multitude of chemical modifications performed on DNA and chromatin that affect the ability of chromatin to be transcribed. In this review, we explore the effects of aging on female and male gametes with a focus on the epigenetic changes that occur in gametes throughout aging. Quality decline in oocytes occurs at a relatively early age. Epigenetic changes constitute an important part of oocyte aging. DNA methylation is reduced with age, along with reduced expression of DNA methyltransferases (DNMTs). Histone deacetylases (HDAC) expression is also reduced, and a loss of heterochromatin marks occurs with age. As a consequence of heterochromatin loss, retrotransposon expression is elevated, and aged oocytes suffer from DNA damage. In sperm, aging affects sperm number, motility and fecundity, and epigenetic changes may constitute a part of this process. 5 methyl-cytosine (5mC) methylation is elevated in sperm from aged men, but methylation on Long interspersed nuclear elements (LINE) elements is reduced. Di and trimethylation of histone 3 lysine 9 (H3K9me2/3) is reduced in sperm from aged men and trimethylation of histone 3 lysine 27 (H3K27me3) is elevated. The protamine makeup of sperm from aged men is also changed, with reduced protamine expression and a misbalanced ratio between protamine proteins protamine P1 and protamine P2. The study of epigenetic reproductive aging is recently gaining interest. The current status of the field suggests that many aspects of gamete epigenetic aging are still open for investigation. The clinical applications of these investigations have far-reaching consequences for fertility and sociological human behavior.

Explaining the Unexplained: Examining the Predictive Value of Semen Parameters, Sperm DNA Fragmentation and Metal Levels in Unexplained Infertility

Background

There is ongoing research to find an optimum modality to predict male fertility potential.

Aims

To compare the semen parameters, sperm DNA damage and seminal metal levels of Zinc, Lead and Aluminium among the male partners of couples with unexplained infertility and men with proven fertility.

Settings and Design

Prospective case-control study at a tertiary level teaching hospital.

Materials and Methods

One hundred male partners of couples with unexplained subfertility and 50 men with proven fertility were included in the study. Male partners of unexplained infertility couples and fertile men were compared for their semen parameters, sperm DNA Fragmentation Index (DFI) and seminal metal levels in semen.

Statistical Analysis Used

Chi-square test, Student's t-test, sensitivity and specificity analysis, binomial logistic regression analysis.

Results

Fertile men had statistically significantly higher mean progressive sperm motility than male partners of unexplained infertility (53.12 ± 9.89% vs. 44.81 ± 19.47%, P = 0.005). Semen volume and sperm concentration were comparable among the cases and control population. The mean sperm DFI was significantly lower among fertile men (10.83 ± 6.28 vs. 21.38 ± 10.28, P < 0.0001). Plotting the receiver-operating characteristic curve the threshold for discrimination was calculated to be 18% DFI. The sensitivity specificity and overall accuracy were 43%, 84% and 56.67%, respectively when the DFI cut-off was set at 18%. Zinc concentration in the semen had a strong positive correlation (Point Biserial correlation coefficient = 0.831) with fertility, whereas lead and aluminium had a moderate negative correlation.

Conclusion

Conventional semen analysis had limited differentiating ability for unexplained infertility. The sperm DFI may be employed for explanatory purposes among couples with unexplained subfertility. A lower discriminatory threshold of DFI (18%) has better overall accuracy as opposed to a 30% cutpoint for unexplained subfertility. Among metals, Zinc was strongly correlated with fertility status.

How Well Do Semen Analysis Parameters Correlate with Sperm DNA Fragmentation? A Retrospective Study from 2567 Semen Samples Analyzed by the Halosperm Test

Sperm DNA fragmentation (SDF) levels have been measured in the workup for in vitro fertilization (IVF) at PIVET since 2007, with the Halosperm test having replaced the previous sperm chromatin structure assay (SCSA) since 2013. Of 2624 semen samples analyzed for the Halosperm test, 57 were excluded as the sperm concentration was <5 million/mL, a level too low for accurate testing, leaving 2567 samples for assessment within this study. The SDF rates were categorized in 5 sperm DNA fragmentation indices (DFI), ranging from <5% to levels >30%, and these categories were correlated with the respective semen analysis profiles and two clinical parameters, namely the age of the male and the ejaculatory abstinence period prior to the sample. The results showed a significant correlation with male age (r = 0.088; p < 0.0001), the abstinence period (r = 0.076; p = 0.0001), and the semen volume (r 0.063; p = 0.001), meaning an adversely high SDF was associated with advanced age, prolonged abstinence, and raised semen volume parameters. There was a significant negative correlation with sperm morphology (r = −0.074; p = 0.0001), progressive motility (r = −0.257; p < 0.0001), and semen pH (r = −0.066; p < 0.001), meaning these semen anomalies were associated with high SDF values. With respect to abnormal morphology, sperm tail defects had a positive correlation (r = 0.096; p < 0.0001) while midpiece defects showed a negative correlation (r = −0.057; p = 0.004), meaning that tail defects are most likely to associate with adverse DFI values. With respect to motility patterns, the poorer patterns showed a positive correlation with increased DFI, namely C pattern (r = 0.055; p = 0.005) and D pattern (r = 0.253; p < 0.0001). These results imply that raised DFI reflects poor sperm quality and should be investigated in clinical trials involving IVF and the consideration of intracytoplasmic sperm injection (ICSI).

Decrease of air pollution during lockdown in Tuscany (Italy): An effect on sperm DNA fragmentation?

In March 2020, the Italian government imposed a national lockdown which was almost completely removed in June 2020. Due to the abrupt stop of human activities, emissions of air pollutants decreased. Air pollution is an environmental risk factor for noncommunicable disease and mortality. Emerging evidence also suggests a role in male infertility. In this study, we compared sperm DNA fragmentation (sDF) levels and conventional semen parameters between subjects undergoing sDF determination and routine semen analysis in a single Italian centre, during about 6 months before (N = 119) and after lockdown (N = 105). After lockdown, we found an improvement of sperm progressive motility (48.00[38.50-58.00]% vs. 42.00[33.00-53.00]%) and sDF levels (as total: 24.79[18.33-33.97]% vs. 35.02[25.04-45.73]%, p < .001; brighter: 14.02[10.69-17.93]% vs 18.54[13.58-25.82]%, p < .001 and dimmer sDF: 9.24[5.64-15.78]% vs. 12.24[8.08-19.10]%, p < .01), mirrored by a decrease of leukocyte semen concentration (p < .01). The improvement of sperm motility and DNA quality was maintained after adjusting for leukocyte concentration and several conditions known to affect sperm motility and/or sDF levels. With a significant decrease in air pollution observed in Tuscany during and after lockdown, associated improvement in sperm motility and DNA quality in patients referred to the infertility clinic is suggestive of the potential role of air pollution in male infertility.

Impact of Advanced Paternal Age on Fertility and Risks of Genetic Disorders in Offspring

The average age of fathers at first pregnancy has risen significantly over the last decade owing to various variables, including a longer life expectancy, more access to contraception, later marriage, and other factors. As has been proven in several studies, women over 35 years of age have an increased risk of infertility, pregnancy problems, spontaneous abortion, congenital malformations, and postnatal issues. There are varying opinions on whether a father's age affects the quality of his sperm or his ability to father a child. First, there is no single accepted definition of old age in a father. Second, much research has reported contradictory findings in the literature, particularly concerning the most frequently examined criteria. Increasing evidence suggests that the father's age contributes to his offspring's higher vulnerability to inheritable diseases. Our comprehensive literature evaluation shows a direct correlation between paternal age and decreased sperm quality and testicular function. Genetic abnormalities, such as DNA mutations and chromosomal aneuploidies, and epigenetic modifications, such as the silencing of essential genes, have all been linked to the father's advancing years. Paternal age has been shown to affect reproductive and fertility outcomes, such as the success rate of in vitro fertilisation (IVF), intracytoplasmic sperm injection (ICSI), and premature birth rate. Several diseases, including autism, schizophrenia, bipolar disorders, and paediatric leukaemia, have been linked to the father's advanced years. Therefore, informing infertile couples of the alarming correlations between older fathers and a rise in their offspring's diseases is crucial, so that they can be effectively guided through their reproductive years.

Sperm DNA fragmentation testing in clinical management of reproductive medicine

Background

Approximately 8%-12% of couples worldwide face infertility, with infertility of individuals assigned male at birth (AMAB) contributing to at least 50% of cases. Conventional semen analysis commonly used to detect sperm abnormalities is insufficient, as 30% of AMAB patients experiencing infertility show normal results in this test. From a genetic perspective, the assessment of sperm DNA fragmentation (SDF) is important as a parameter of sperm quality.

Methods

In this narrative study, we review and discuss pathophysiological causes, DNA repair mechanisms, and management of high SDF. We then summarize literature exploring the association between SDF and reproductive outcomes.

Main Findings

Recent systematic reviews and meta-analyses have revealed a significant association between high SDF in AMAB individuals and adverse reproductive outcomes including embryo development, natural conception, intrauterine insemination, and in vitro fertilization. However, the association with live birth rates and pregnancy rates following intracytoplasmic injection remains inconclusive. The disparities among quantitative assays, inconsistent reference range values, absent high-quality prospective clinical trials, and clinical heterogeneity in AMAB patients with elevated SDF represent the main limitations affecting SDF testing.

Conclusion

The evaluation and management of SDF plays an important role in a subset of AMAB infertility, but widespread integration into clinical guidelines will require future high-quality clinical trials and assay standardization.

Altered DNA methylation in estrogen-responsive repetitive sequences of spermatozoa of infertile men with shortened anogenital distance

BACKGROUND

It has been suggested that antenatal exposure to environmental endocrine disruptors is responsible for adverse trends in male reproductive health, including male infertility, impaired semen quality, cryptorchidism and testicular cancer, a condition known as testicular dysgenesis syndrome. Anogenital distance (AGD) is an anthropomorphic measure of antenatal exposure to endocrine disruptors, with higher exposure levels leading to shortened AGD. We hypothesized that exposure to endocrine disruptors could lead to changes in DNA methylation during early embryonic development, which could then persist in the sperm of infertile men with shortened AGD.

RESULTS

Using fluorescence activated cell sorting based on staining with either YO-PRO-1 (YOPRO) or chromomycin-3 (CMA3), we isolated four sperm fractions from eleven infertile men with short AGD and ten healthy semen donors. We examined DNA methylation in these sorted spermatozoa using reduced representation bisulfite sequencing. We found that fractions of spermatozoa from infertile men stained with CMA3 or YOPRO were more likely to contain transposable elements harboring an estrogen receptor response element (ERE). Abnormal sperm (as judged by high CMA3 or YOPRO staining) from infertile men shows substantial hypomethylation in estrogenic Alu sequences. Conversely, normal sperm fractions (as judged by low CMA3 or YO-PRO-1 staining) of either healthy donors or infertile patients were more likely to contain hypermethylated Alu sequences with ERE.

CONCLUSIONS

Shortened AGD, as related to previous exposure to endocrine disruptors, and male infertility are accompanied by increased presence of hormonal response elements in the differentially methylated regulatory sequences of the genome of sperm fractions characterized by chromatin decondensation and apoptosis.

Is There a Relationship between Sperm DNA Fragmentation and Intra-Uterine Insemination Outcome in Couples with Unexplained or Mild Male Infertility? Results from the ID-Trial

BACKGROUND

Sperm DNA fragmentation has been proposed as a candidate test for the assessment of sperm function on the premise that damage to the sperm chromatin is associated with a detrimental reproductive outcome. The objective of our study was to investigate whether sperm DNA fragmentation testing has a prognostic value, and thus can play a pivotal role in selecting future patients for intra-uterine insemination (IUI) therapy.

METHODS

This was a prospective cohort study conducted in a University Hospital setting. SDF was measured through TUNEL assay on the fresh semen sample presented at diagnosis and at insemination in couples with idiopathic/mild male infertility undergoing natural cycle IUI treatment. The generalized estimating equation (GEE)-model and multivariable model were used to analyze the probability of live birth and clinical pregnancy, respectively. ROC analysis was carried out to determine an SDF cut-off.

RESULTS

There was an inverse relationship between SDF in the ejaculate of the diagnostic semen sample and CP (p = 0.02; OR 0.94 95% CI (0.90, 0.989)) as well as LB (p = 0.04; OR 0.95 95% CI (0.90, 0.9985)). No significant association was found between SDF after gradient and IUI outcome in the diagnostic sample nor between SDF (ejaculate/after gradient) in the IUI samples. The ROC analysis proposed a cutoff of 17.5% as the best compromise between sensitivity and specificity in the diagnostic SDF for live birth; however, the test diagnostics are low, with an AUC of 0.576.

CONCLUSIONS

Overall, this study strengthens the hypothesis of an inverse relationship between SDF and CP/LB. Furthermore, SDF taken together with other clinical characteristics might provide more insight into male reproductive potential and predicting IUI outcome. Couples with SDF ≥ 17.5% in the diagnostic semen sample did not reach live birth. Further research is necessary to establish the diagnostic and prognostic potential of SDF as an add-on test.

Normal Sperm DNA Integrity in Patients With Inflammatory Bowel Disease on Ustekinumab Maintenance Therapy

We demonstrate that ustekinumab does not adversely affect semen quality or sex hormones in male patients. Ustekinumab is not detectable in semen and poses no risk to partners. Our observations support a recommendation to continue ustekinumab therapy in patients wishing to conceive.

The Association of Sperm DNA Fragment and Assisted Reproductive Outcomes: A Meta-Analysis

Objective

To analyze the effect of sperm DNA fragmentation index (DFI) on the outcomes of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).

Methods

Literature search was conducted on English databases PubMed, Cochrane, and Embase to obtain eligible studies.

Results

A total of 11 cohort studies were included and analyzed using the random effects model. The results illustrated that the IVF fertilization rate (RR = 0.94, 95% CI: 0.77-1.14, P = 0.61), pregnancy rate (RR = 0.83, 95% CI: 0.57-1.21, P = 0.32), and live birth rate (RR = 0.53, 95% CI: 0.16-1.80, P = 0.31) in the high DFI group were statistically insignificant with those in the low FI group. The correlations between DFI and ICSI fertilization rate (RR = 0.79, 95% CI: 0.52-1.18, P = 0.25), pregnancy rate (RR = 0.89, 95% CI: 0.74-1.06, P = 0.18), and live birth rate (RR = 0.89, 95% CI: 0.70-1.14, P = 0.36) were also not statistically significant.

Conclusion

This study has observed no significant correlation between sperm DFI and assisted reproductive outcomes. Multicenter large-sample clinical trials are required to conclusively determine the impact of DNA damage on the clinical outcomes of assisted reproduction.

Reactive Oxygen Species and Their Consequences on the Structure and Function of Mammalian Spermatozoa

Significance: Among the 200 or so cell types that comprise mammals, spermatozoa have an ambiguous relationship with the reactive oxygen species (ROS) inherent in the consumption of oxygen that supports aerobic metabolism. Recent Advances: In this review, we shall see that spermatozoa need the action of ROS to reach their structural and functional maturity, but that due to intrinsic unique characteristics, they are, perhaps more than any other cell type, susceptible to oxidative damage. Recent studies have improved our knowledge of how oxidative damage affects sperm structures and functions. The focus of this review will be on how genetic and epigenetic oxidative alterations to spermatozoa can have dramatic unintended consequences in terms of both the support and the suppression of sperm function. Critical Issues: Oxidative stress can have dramatic consequences not only for the spermatozoon itself, but also, and above all, on its primary objective, which is to carry out fertilization and to ensure, in part, that the embryonic development program should lead to a healthy progeny. Future Directions: Sperm oxidative DNA damage largely affects the integrity of the paternal genetic material to such an extent that the oocyte may have difficulties in correcting it. Diagnostic and therapeutic actions should be considered more systematically, especially in men with difficulties to conceive. Research is underway to determine whether the epigenetic information carried by spermatozoa is also subject to changes mediated by pro-oxidative situations. Antioxid. Redox Signal. 37, 481-500.

Comparison of sperm preparation methods to improve the recovery of mature spermatozoa in sub-fertile males

The integrity of chromatin in the spermatozoon is essential for reproductive outcome. The aim of this study was to evaluate the most effective and cost-effective method to reduce the percentage of spermatozoa with defects in chromatin decondensation for use in assisted reproductive technologies (ART) procedures. Sperm samples from 15 sub-fertile males were examined at CFA Naples to determine the sperm decondensation index (SDI), using the aniline blue test, before and after preparation, comparing density gradients with two different swim-up approaches. All three techniques led to a reduction in decondensed spermatozoa with no statistical difference (P > 0.05) between the control and the treated sperm. In contrast, we found a highly significant decrease in SDI (P < 0.01) after the two swim-up methods in all the samples, confirming the efficacy of these methods in lowering the percentage of chromatin compaction damage. There was no statistical difference between the two swim-up methods, however swim-up from the pellet led to improved count, motility and the percentage of normal condensed spermatozoa. We suggest that swim-up from the pellet be used in ART on sub-fertile males, both to reduce cell stress by multiple centrifugation and improve the recovery rate of mature spermatozoa.

Low-dose Methotrexate Therapy Does Not Affect Semen Parameters and Sperm DNA

BACKGROUND

Methotrexate is widely used in inflammatory diseases during the patients' reproductive years. The effect on male fertility and sperm DNA integrity is largely unknown. We evaluated sperm DNA integrity and basic semen parameters according to the World Health Organization (WHO) in male patients with inflammatory diseases treated with methotrexate.

METHODS

Semen samples from 14 patients on low-dose maintenance methotrexate were compared with samples from 40 healthy volunteers. Further, 5 patients delivered samples on and off methotrexate therapy for paired comparison. Sperm DNA fragmentation index (DFI), concentration, motility, and morphology were evaluated. Blood sex hormones and methotrexate levels were measured in blood and semen.

RESULTS

DNA fragmentation index in methotrexate-treated patients was comparable with that in healthy volunteers (DFI, 11.5 vs 15.0; P = .06), and DFI did not change significantly on and off methotrexate in the paired samples (DFI, 12.0 vs 14.0; P = 0.35). Sperm concentration, motility, and morphology did not differ between men treated with methotrexate and healthy volunteers. Sperm progressive motility increased off therapy compared with on therapy (65.0% vs 45.0%, P = .04), but all fluctuations in progressive motility were within the WHO reference interval. All methotrexate polyglutamates1-5 were detected in blood, but only methotrexate polyglutamate1 in semen. Serum testosterone was unaffected by methotrexate therapy.

CONCLUSIONS

Patients treated with low-dose methotrexate have a sperm quality comparable with that of healthy volunteers, and methotrexate treatment does not increase sperm DNA fragmentation. This study does not support cryopreservation of semen before treatment initiation nor a 3-month methotrexate-free interval prior to conception.

Evaluation of selected semen parameters and biomarkers of male infertility - preliminary study

Background: Because the etiopathogenesis of male infertility is multifactorial our study was designed to clarify the relationship between standard semen parameters, testicular volume, levels of reproductive hormones and the fragmentation of sperm nuclear DNA (SDF). Methods: Patients (n = 130) were clustered as subjects: 1) with an abnormal volume (utrasonography) of at least one testis (<12 mL) or with a normal volume of testes and 2) with abnormal levels of at least one of the reproductive hormones (FSH, LH, PRL, TSH, total T - electrochemiluminescence method) or with normal hormonal profiles and 3) with high level of SDF (>30%), moderate (>15-30%) or low (≤15%) (sperm chromatin dispersion test). Results: In subjects with a decreased testicular volume and in subjects with abnormal levels of reproductive hormones, decreased basic semen parameters were found. Participants with abnormal testicular volume had a higher percentage of SDF and a higher level of FSH (Mann-Whitney U test). In turn, men with a high level of SDF had lower testicular volume and conventional sperm parameters than men with a low level of SDF (Kruskal-Wallis test). Conclusions: We showed that spermatogenesis disorders coexisted with decreased testicular volume and increased FSH levels. The disorders of spermatogenesis were manifested by reduced basic sperm characteristics and a high level of sperm nuclear DNA damage.

The Relationship between the Testicular Blood Flow and the Semen Parameters of Rams during the Selected Periods of the Breeding and Non-Breeding Seasons

The study aimed to conduct advanced semen evaluation tests during routine ram examination periods in the breeding and non-breeding seasons and to investigate their correlation with the dynamics of testicular blood flow. Semen was collected from eighteen rams, and pulse wave Doppler examination before (BBS), during (BS), and after the breeding season (ABS). Routine and advanced semen analysis, including computer-assisted sperm analysis (CASA), sperm chromatin dispersion test (SCD), and motile sperm organelle morphology examination (MSOME), were conducted. In Doppler ultrasonography, the peak systolic velocity (PSV), end-diastolic velocity (EDV), resistive index (RI), and pulsatility index (PI) were calculated. In BS period, high sperm concentration (p < 0.0001) and total sperm number/ejaculate (p = 0.008) were noted. During the BBS period, a low percentage of forwarding motility (p = 0.017) and high sperm abnormalities (p = 0.005) were found. Also during this period, both SCD and MSOME revealed high sperm DNA fragmentation (p < 0.0001) and signs of vacuolization (Grade II-IV, p < 0.05). The advanced features of higher sperm abnormalities (Grade IV of MSOME) correlated with an increase RI (ρє <0.60;0.61>) and PI (ρє <0.46;0.52>), whereas the basic percentage of sperm abnormalities correlated with the EDV (ρє <0.44;0.73>) value. One may conclude that the current preliminary study requires further research concerning the monthly examination of a ram to provide full yearly characteristics of the relation between advanced semen evaluation tests and the dynamics of testicular blood flow.

Role of Female Age in Regulating the Effect of Sperm DNA Fragmentation on the Live Birth Rates in Intracytoplasmic Sperm Injection Cycles with Own and Donor Oocytes

Background

Sperm DNA integrity assessment has been progressively used as an unfettered measure of sperm as it proffers more prognostic and diagnostic information than routine semen analysis. The contentious effect of sperm DNA fragmentation (SDF) on clinical outcomes can be attributed to female factors such as age, oocyte quality and ovarian reserve.

Aims

The study is mainly aimed to know the influence of SDF on the live birth rates in intracytoplasmic sperm injection (ICSI) cycles with own and donor oocytes. Second, to know the role of female age in regulating the effect of SDF on the live birth rates in ICSI cycles with own and donor oocytes.

Setting and Design

A prospective cohort study was done at our tertiary care centre attached to the reproductive medicine unit in medical college.

Materials and Methods

The study included 356 patients who underwent first ICSI cycles either with own or donor-oocytes along with day 5 fresh embryo transfers only. The main outcome measures were live birth rates and miscarriage rates.

Statistical Analysis Used

Chi-squared test was used to compare the categorical variables between the groups. The receiver operating characteristic curve was developed to correlate the female age with the live birth rate.

Results

A significant decrease in the live birth rates (42.85% vs. 26.15%, P = 0.023) and an increase in the miscarriage rates (12.30% vs. 34.61%, P = 0.013) were observed in the high-SDF group ICSI cycles of own-oocyte patients. However, there was no significant difference in the live birth rates and miscarriage rates in the low- and high-SDF groups of donor oocyte ICSI cycle patients (P > 0.05). The own-oocyte ICSI cycle patients were further stratified based on the female age. In the female age group ≤30 years there was no significant difference in the live birth and miscarriage rates (P > 0.05) similar to donor oocyte ICSI cycles. Whereas, there was a significant difference in the live birth rates in the females of age >30 years (13.79% vs. 34.37%, P = 0.040).

Conclusion

In conclusion, high-SDF has a negative influence on the live birth rates and a positive influence on the miscarriage rates in patients with own-oocyte ICSI cycles. A similar influence was not observed in patients with donor-oocyte ICSI cycles and in young female patients (age ≤30 years) with own-oocyte ICSI cycles.

Effect of curcumin on sperm parameters after the cryopreservation

OBJECTIVE

Cryopreservation refers to the cooling of cells and tissues to sub-zero temperatures in order to stop all biologic activity and preserve them for future use. Human sperm cryopreservation is an important tool for assisted reproductive technology and male fertility preservation. However, cryopreservation significantly reduces the quality of spermatozoa. The antioxidant effects of curcumin on different cells have been widely reported. This study was aimed to evaluate changes in post-thaw viability, morphology, motility, chromatin condensation and DNA integrity in response to the addition of curcumin to human sperm freezing extender.

MATERIALS AND METHODS

Semen of 23 normozoospermic men was collected and each sample was divided into three equal aliquots: Control, DMSO, Curcumin. The samples were analyzed freshly for viability (Eosin Y), morphology (Diff-Quick), motility (following WHO standarts), sperm chromatin packaging (aniline blue) and DNA integrity (acridine orange). The control group remained untreated and was mixed with cryopreservation medium (in-house 1:1). The DMSO group was mixed with cryopreservation medium containing 0.1% DMSO. The curcumin group was mixed with cryopreservation medium containing 10 µM curcumin. Samples stained with Diff-Quick and aniline blue were examined under light microscope, samples stained with Eosin Y were examined under phase-contrast microscope and samples stained with acridine orange were examined under fluorescence microscope. Ten days after cryopreservation, samples were thawed and pre-freeze analyses repeated.

RESULTS

Obtained results showed that cryopreservation significantly (P < 0.001) reduces sperm parameters. In Curcumin group, progressive motility, sperm chromatin condensation and DNA integrity significantly (P < 0.001) increased after the thawing process, as compared with the control and the DMSO group.

CONCLUSION

These results suggest that the addition of curcumin to cryopreservation medium improves post-thaw progressive motility, sperm chromatin condensation and DNA integrity. It seems that curcumin ameliorates detrimental effects of cryopreservation on human spermatozoa. Further research is needed on the use of curcumin and other antioxidant substances in sperm cryopreservation.

Sperm DNA fragmentation index and cumulative live birth rate in a cohort of 2,713 couples undergoing assisted reproduction treatment

OBJECTIVE

To study how the choice of the first assisted reproductive technology treatment type affects the cumulative live birth rate (CLBR) in couples with high sperm DNA fragmentation index (DFI).

DESIGN

Longitudinal cohort study.

SETTING

University-affiliated fertility clinic.

PATIENT(S)

A total of 2,713 infertile couples who underwent assisted reproductive technology treatment between 2007 and 2017 were included in the study. All in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatments (up to three fresh treatments and all associated frozen-thawed embryo transfers) offered to the couples by the public health care system were included, in total 5,422 cycles.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The primary outcome was the CLBR. The secondary outcomes were the fertilization rate and the miscarriage rate. The IVF and ICSI groups were defined according to the method applied in the first treatment cycle.

RESULT(S)

In the IVF group, the CLBR values were higher for couples with normal DFI compared with those for couples with high DFI (≥20%) (48.1% vs. 41.6% for conservative CLBR estimate and 55.6% vs. 51.4% for optimal CLBR estimate after adjustment for female age, respectively). No DFI-dependent difference was seen in the ICSI group.

CONCLUSION(S)

Our results demonstrated that a high DFI predicts a statistically significantly lower CLBR if IVF and not ICSI is applied in the first cycle of assisted reproduction.

Implementation of an in-house flow cytometric analysis of DNA fragmentation in spermatozoa

An increased amount of DNA fragmentation in the spermatozoa (SDF) is linked to male infertility. The Sperm Chromatin Structure Assay (SCSA) is widely used for analysis of SDF. However, the current software (SCSASoft^®) linked to this assay is licensed and often located within larger diagnostic centers. In this study, we present a protocol for using other types of software than SCSASoft^® to determine the SDF index (DFI) with clinical relevance. This protocol is engineered after collecting and analyzing 254 samples from fertility patients and sperm donors over a 15-month period. DFI is analyzed using a strict protocol where the spermatozoa are treated with a strong acid (pH 1.2) followed by acridine orange. DFI is determined by a standard flow cytometric software, FACSDiva 6.1.3. Analysis of the outcome of the fertility treatment is included for 137 patients receiving either intrauterine inseminations (IUI) or timed coitus (TC). The results show that the chance of pregnancy declines as DFI increases. We also found that the male DFI affects the chance of pregnancy independent of the female age. We have shown that a standard flow cytometric software can be used when determining a clinical relevant DFI. These findings are a significant step toward implementing the analysis as a part of the routine, in-house diagnosing of the male fertility patient and subsequently optimizing the treatment course of the couple with reduced human and financial costs.

Semen evaluation: methodological advancements in sperm quality-specific fertility assessment - A review

Assessment of male fertility is based on the evaluation of sperm. Semen evaluation measures various sperm quality parameters as fertility indicators. However, semen evaluation has limitations, and it requires the advancement and application of strict quality control methods to interpret the results. This article reviews the recent advances in evaluating various sperm-specific quality characteristics and methodologies, with the help of different assays to assess sperm-fertility status. Sperm evaluation methods that include conventional microscopic methods, computer-assisted sperm analyzers (CASA), and flow cytometric analysis, provide precise information related to sperm morphology and function. Moreover, profiling fertility-related biomarkers in sperm or seminal plasma can be helpful in predicting fertility. Identification of different sperm proteins and diagnosis of DNA damage has positively contributed to the existing pool of knowledge about sperm physiology and molecular anomalies associated with different infertility issues in males. Advances in methods and sperm-specific evaluation has subsequently resulted in a better understanding of sperm biology that has improved the diagnosis and clinical management of male factor infertility. Accurate sperm evaluation is of paramount importance in the application of artificial insemination and assisted reproductive technology. However, no single test can precisely determine fertility; the selection of an appropriate test or a set of tests and parameters is required to accurately determine the fertility of specific animal species. Therefore, a need to further calibrate the CASA and advance the gene expression tests is recommended for faster and field-level applications.

DNA Fragmentation in Human Spermatozoa and Pregnancy Rates after Intrauterine Insemination. Should the DFI Threshold Be Lowered?

Sperm DNA fragmentation index (DFI) can be analyzed by a flow cytometric assay after treatment with acid and acridine orange. In this prospective, cohort study, the value of DFI was determined in a semen analysis collected before fertility treatment (baselineDFI) in 146 couples and during 1–3 intrauterine inseminations (IUI) in 211 couples (511 cycles). The pregnancy rate (PR)/cycle was 9.9% if baselineDFI was >10 and 21.7% if baselineDFI was ≤10, (p < 0.005). The live birth rate (LBR)/cycle was 5% if baselineDFI was >10 and 14.2% if baselineDFI was ≤10 (p < 0.005). PR/patient was 23.1% if baselineDFI was >10 and 45.5% if baselineDFI was ≤10 (p < 0.005). LBR/patient was 12.4% if baselineDFI was >10 and 34% if baselineDFI was ≤10 (p < 0.005). When isolating non-stimulated IUI cycles and couples with female age < 35, a significant difference in PR and LBR between couples with high DFI and low DFI was seen. Results suggest that DFI > 10 could advice against timed coitus and non-stimulated IUI cycles. Analysis for DFI performed before treatment provides information about PR and LBR after IUI.

Sperm DNA fragmentation and male fertility: a retrospective study of 5114 men attending a reproductive center

PURPOSE

The sperm DNA fragmentation index (DFI) was quantitatively measured and its relationship with age, semen quality, and infertility conditions was investigated.

METHODS

Semen routine test and sperm DFI were performed in 2760 infertile male and 2354 male whose spouse experienced at least one unexplained miscarriage to analyze the correlation between sperm DNA damage, semen routine parameters, and age.

RESULTS

Sperm DFI was significantly lower from patients whose wife experienced unexplained miscarriage compared to infertility males (p = 0.000). An inverse correlation between sperm DFI and sperm progressive motility was observed (r_s = - 0.465, p = 0.000) and sperm DFI was positively correlated with age (r_s = 0.255, p = 0.000). However, the correlation between sperm DFI and sperm concentration, semen volume, total sperm count, and motile sperm count were not proved.

CONCLUSIONS

Sperm DFI is an important indicator for evaluating the quality of semen. Sperm DNA integrity testing is preferentially recommended to those who have decreased sperm progressive motility, especially older men. An integrative analysis of sperm DFI, sperm progressive motility, age, and infertility conditions can provide a more comprehensive assessment of male fertility.

DNA fragmentation of sperm in automobile painters

Reproductive health is a major concern for workers constantly exposed to chemicals at work, especially in developing countries. The problems mainly stemmed from chronic exposure to the chemicals contained in paint thinner, which is mainly toluene, used during automobile painting. Unfortunately, in Indonesia, there is no study on the reproductive health of male workers in automobile workshops, especially in relation to spermatogenesis. This study aimed to explore the possibility of reproductive problems, namely spermatozoa DNA fragmentation, among male workers in an automobile workshop in Malang. We recruited workers who have worked as automobile painters for years at an automobile workshop in Malang and have been chronically exposed to thinner. Semen samples were collected from 15 automobile workshop workers who were married and had children. Twelve office workers were used as the control group. The two groups of semen samples were tested with the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay combined with propidium iodide and analyzed by flow cytometry. The results showed a significant difference between DNA fragmentation of the control group and workshop workers at 14.9% and 47.66%, respectively. Risk factor analysis showed a significant increase in risk factors (p = 0.001). Taken together, chronic exposure to paint thinner in those engaged in painting at the automobile workshop increased the risk of DNA fragmentation in spermatozoa. Our study highlighted the importance of health education for the risked workers on minimization of exposure, which could be recommended to the health policy makers.

Negative Impact of Elevated DNA Fragmentation and Human Papillomavirus (HPV) Presence in Sperm on the Outcome of Intra-Uterine Insemination (IUI)

We wanted to determine the sperm DNA fragmentation index (DFI) cutoff for clinical pregnancies in women receiving intra-uterine insemination (IUI) with this sperm and to assess the contribution of Human Papillomavirus (HPV) infection on sperm DNA damage and its impact on clinical pregnancies. Prospective non-interventional multi-center study with 161 infertile couples going through 209 cycles of IUI in hospital fertility centers in Flanders, Belgium. Measurement of DFI and HPV DNA with type specific quantitative PCRs (HPV 6, 11, 16, 18, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66 and 68) in sperm before its use in IUI. Clinical pregnancy (CP) rate was used as the outcome to analyze the impact on fertility outcome and to calculated the clinical cutoff value for DFI. A DFI criterion value of 26% was obtained by receiver operating characteristic (ROC) curve analysis. Couples with a male DFI > 26% had significantly less CPs than couples with DFI below 26% (OR 0.0326; 95% CI 0.0019 to 0.5400; p = 0.017). In sperm, HPV prevalence was 14.8%/IUI cycle. Sperm samples containing HPV had a significantly higher DFI compared to HPV negative sperm samples (29.8% vs. 20.9%; p = 0.011). When HPV-virions were present in sperm, no clinical pregnancies were observed. More than 1 in 5 of samples with normal semen parameters (17/78; 21.8%) had an elevated DFI or was HPV positive. Sperm DFI is a robust predictor of clinical pregnancies in women receiving IUI with this sperm. When DFI exceeds 26%, clinical pregnancies are less likely and in vitro fertilization techniques should be considered.

Lack of trusted diagnostic tools for undetermined male infertility

Semen analysis is the cornerstone of evaluating male infertility, but it is imperfect and insufficient to diagnose male infertility. As a result, about 20% of infertile males have undetermined infertility, a term encompassing male infertility with an unknown underlying cause. Undetermined male infertility includes two categories: (i) idiopathic male infertility-infertile males with abnormal semen analyses with an unknown cause for that abnormality and (ii) unexplained male infertility-males with "normal" semen analyses who are unable to impregnate due to unknown causes. The treatment of males with undetermined infertility is limited due to a lack of understanding the frequency of general sperm defects (e.g., number, motility, shape, viability). Furthermore, there is a lack of trusted, quantitative, and predictive diagnostic tests that look inside the sperm to quantify defects such as DNA damage, RNA abnormalities, centriole dysfunction, or reactive oxygen species to discover the underlying cause. To better treat undetermined male infertility, further research is needed on the frequency of sperm defects and reliable diagnostic tools that assess intracellular sperm components must be developed. The purpose of this review is to uniquely create a paradigm of thought regarding categories of male infertility based on intracellular and extracellular features of semen and sperm, explore the prevalence of the various categories of male factor infertility, call attention to the lack of standardization and universal application of advanced sperm testing techniques beyond semen analysis, and clarify the limitations of standard semen analysis. We also call attention to the variability in definitions and consider the benefits towards undetermined male infertility if these gaps in research are filled.

Semiquantitative promoter methylation of MLH1 and MSH2 genes and their impact on sperm DNA fragmentation and chromatin condensation in infertile men

To investigate the semiquantitative methylation alterations of MLH1 and MSH2 and the possible association among methylation of MLH1 and MSH2, sperm DNA fragmentation and sperm chromatin condensation in idiopathic oligoasthenoteratozoospermic men. Seventy-five idiopathic infertile men and 52 fertile and/or normozoospermic men were included in the study. SDF was analysed using the TUNEL assay in semen samples of 100 men. Promoter methylation of MLH1 and MSH2 genes was assessed by semiquantitative methylight analysis in semen samples of 39 and 40 men respectively. Sperm chromatin condensation was evaluated using aniline blue staining in 114 men. MLH1 promoter methylation was positively correlated with the percentage of aniline blue positive spermatozoa (r = 0.401, p = 0.0188). On the other hand, MSH2 promoter methylation was negatively correlated with sperm concentration and total sperm count (r = -0.421, p = 0.0068 and r = 0.4408, p = 0.009 respectively). The percentage of aniline blue positive spermatozoa in the control group was significantly lower than in the OAT group (p < 0.0001) and negatively correlated with total sperm count (r = -0.683, p < 0.0001), progressive sperm motility (r = -0.628, p < 0.0001), total motility (r = -0.639, p < 0.0001) and normal morphology (r = -0.668, p < 0.0001). Promoter methylation profile of MLH1 and MSH2 genes may play role on sperm DNA packaging and conventional semen parameters respectively.

Sperm DNA Fragmentation: A New Guideline for Clinicians

Sperm DNA integrity is crucial for fertilization and development of healthy offspring. The spermatozoon undergoes extensive molecular remodeling of its nucleus during later phases of spermatogenesis, which imparts compaction and protects the genetic content. Testicular (defective maturation and abortive apoptosis) and post-testicular (oxidative stress) mechanisms are implicated in the etiology of sperm DNA fragmentation (SDF), which affects both natural and assisted reproduction. Several clinical and environmental factors are known to negatively impact sperm DNA integrity. An increasing number of reports emphasizes the direct relationship between sperm DNA damage and male infertility. Currently, several assays are available to assess sperm DNA damage, however, routine assessment of SDF in clinical practice is not recommended by professional organizations. This article provides an overview of SDF types, origin and comparative analysis of various SDF assays while primarily focusing on the clinical indications of SDF testing. Importantly, we report four clinical cases where SDF testing had played a significant role in improving fertility outcome. In light of these clinical case reports and recent scientific evidence, this review provides expert recommendations on SDF testing and examines the advantages and drawbacks of the clinical utility of SDF testing using Strength-Weaknesses-Opportunities-Threats (SWOT) analysis.

Sperm content of TXNDC8 reflects sperm chromatin structure, pregnancy establishment, and incidence of multiple births after ART

Male germline-specific thioredoxin domain containing 8 (TXNDC8; alias SPTRX3) accumulates indefective human spermatozoa. We assessed the efficiency of two-step semen purification inremoving spermatozoa carrying TXNDC8, and examined the relationship of TXNDC8 with theoutcomes of assisted reproductive therapy (ART), conventional semen parameters, and sperm DNA integrity in sperm chromatin structure assay (SCSA). Semen samples (n = 255) from 91 ART couples were screened in two independent trials, both including a two-step, gradient-and-swim-up separation procedure yielding A-samples (raw semen), B-samples (gradient separated), and C-samples (gradient-and-swim-up). The C-samples were used for intracytoplasmic sperm injection (ICSI) with morphologically selected spermatozoa (IMSSI). Percentage of TXNDC8-positive spermatozoaincreased progressively from A to B/C-samples in both trials. In the first trial (35 couples), the TXNDC8 correlated positively with sperm DNA fragmentation index (%DFI; r = 0.66) measured before separation, and negatively with sperm concentration (r = -0.57) and motility (r = -0.67), also taken before separation. The high DNA stainability index (%HDS) correlated with the percentage of spermatozoa lacking TXNDC8 (r = 0.68). Both SCSA and TXNDC8 parameters showed moderate correlations (r = 0.33-0.66) with blood serum levels of hCG on day 11 (Beta 1) and day13 (Beta 2) after oocyte retrieval. In the second trial (56 couples), fathers of multiplets had a significantly lower percentage of TXNDC8-positive spermatozoa in B-sample (gradient separationonly) compared to men who conceived a singleton pregnancy (p = 0.01) and those who produced no pregnancy (p = 0.02). Those multiplets' fathers also had a significantly higher sperm concentration while their SCSA parameters did not differ from others. It is concluded that theTXNDC8 levels correlate with SCSA and conventional raw semen parameters, and are predictive of pregnancy outcome and multiple births after ART. Two-step purification does not efficiently remove TXNDC8 carrying spermatozoa.

ABBREVIATIONS

ART- assisted reproductive therapy; DFI- DNA fragmentation index; FC- flow cytometry (FC); hCG: human chorionic gonadotropin; HDS: high DNA stainability index; HEPES- (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid); HTF- human tubal fluid; ICSI- intracytoplasmic sperm injection; IgG- immunoglobulin G; IMSSI- ICSI with morphologically selected spermatozoa; IVF- in vitro fertilization; IU-: intrauterine insemination; NGS- normal goat serum; PBS- phosphate buffered saline; PVP- polyvinylpyrrolidone; SAB- spontaneous abortion; SCSA- sperm chromatin structure assay; SPTRX3- spermatid specific thioredoxin 3; SSS- synthetic serum substitute; TRITC- tetramethyl rhodamine isothiocyanate; TX-100- Triton X-100; TXNDC- thioredoxin domain-containing proteins; TXNDC8- thioredoxin domain containing 8; TUNEL- Terminal deoxynucleotidyl transferase dUTP nick end labeling.

Could high DNA stainability (HDS) be a valuable indicator of sperm nuclear integrity?

Background

The Sperm Chromatin Structure Assay (SCSA®), in addition to identifying the DNA Fragmentation Index (DFI) also identifies High DNA satiability (HDS), supposed to reflect the nuclear compaction of spermatozoa. However, data on what exactly this parameter reveals, its relevance and usefulness are contradictory. In order to shed light on this situation, spermatozoa of a cohort (N = 397) of infertile men were subjected to the SCSA®, TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling) and CMA3 (Chromomycin A3) tests. In a smaller subcohort (N = 100), aniline blue (AB) and toluidine blue (TB) staining were performed in addition. The objective of this study was thus to answer the question of whether HDS is a relevant and reliable parameter to be taken into account?

Results

HDS does not appear to be a reliable indicator of nuclear immaturity because it shows a weak correlation with the CMA3, AB and TB stains. The low correlation of HDS with sperm DNA fragmentation (TUNEL and SCSA®) and DNA condensation (CMA3, AB and TB) tests suggests that these two parameters could be decoupled. Unlike DFI and TUNEL, HDS has not been shown to correlate with classic clinical situations of male infertility (asthenozoospermia, teratozoospermia or astheno-teratozoospermia).

Conclusion

HDS correlates poorly with most tests that focus specifically on the level of maturity of the sperm nucleus. To our knowledge, this study is the first to compare SCSA®, TUNEL, AB, TB and CMA3 assays on identical samples. It shows the potency, consistency and limitations of each test and the care that must be taken in their interpretation.

Importance of a semen analysis report for determining the relationship between SCSA sperm DNA fragmentation index and assisted reproductive technology pregnancy rate

In the past, semen parameters have been the primary diagnostic criteria used to establish male infertility. However, with the exception of sperm motility, which is known to be linked to rates of in vitro fertilization success, these parameters are generally unreliable at accurately predicting the potential fertility of a couple. More recent research has suggested that sperm DNA fragmentation index (DFI) may be a more robust and reliable means of predicting assisted reproductive outcomes. The present study aimed to assess the relationship between sperm motility, sperm DFI, and rates of clinical pregnancy by analyzing data from 3000 couples dealing with infertility. Using the most recent semen analysis reports available from male partners in these couples, we assessed these parameters and found that the lower the sperm DFI value, the higher the rate of clinical pregnancy. When we assessed the correlation between sperm DFI, sperm motility, and clinical pregnancy, we observed a strong negative correlation between DFI and motility, but observed no significant relationship between sperm motility and pregnancy rates. These results thus indicate that the measurement of DFI via a sperm chromatin structure assay (SCSA) may be a valuable tool for analyzing semen in order to better predict and improve pregnancy rates in infertile couples.

TUNEL assay-Standardized method for testing sperm DNA fragmentation

Sperm DNA integrity is important for normal functions such as fertilization, implantation, pregnancy and fetal development. Sperm DNA fragmentation (SDF) is more common in infertile men and may be responsible for poor reproductive function. Although there are a number of tests available to measure SDF, the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-nick end labelling TUNEL) assay using flow cytometry is becoming more popular to measure the sperm DNA fragmentation. It is a direct test that measures both single- and double- DNA strand breaks. In this review, we describe the protocol, quality control and measurement of sperm DNA fragmentation using a benchtop flow cytometer. We also briefly discuss the factors that can affect the results, challenges and clinical implications of TUNEL in assessing male infertility.

Comparative analysis of tests used to assess sperm chromatin integrity and DNA fragmentation

Male infertility has a complex etiology, and many times, the cause is unknown. While routine semen analysis provides an overview of basic semen parameters, such as sperm concentration, motility, viability and morphology, a significant overlap of these parameters has been reported in fertile and infertile men. Moreover, conventional semen parameters do not reveal the cellular or molecular mechanisms of sperm dysfunctions leading to infertility. Therefore, sperm functional parameters, including sperm chromatin integrity, are evaluated to provide information on subtle sperm defects that are not routinely identified. Incomplete or defective sperm chromatin condensation increases the susceptibility of the sperm DNA to oxidative damage or other factors. To evaluate sperm chromatin integrity, different methods with varying degrees of diagnostic and prognostic capabilities are available. Among these assays, SCSA, TUNEL and SCD assays are most commonly used. While these assays rather evaluate the DNA directly for damages, the aniline blue and chromomycin A3 stains test for the quality of chromatin condensation. Thus, this review discusses and compares different methods used to evaluate sperm chromatin integrity and condensation, and their inclusion in the routine evaluation of the male infertility.

DNA Fragmentation in Viable and Non-Viable Spermatozoa Discriminates Fertile and Subfertile Subjects with Similar Accuracy

Sperm DNA fragmentation (sDF) negatively affects reproduction and is traditionally detected in total sperm population including viable and non-viable spermatozoa. Here, we aimed at exploring the ability of DNA fragmentation to discriminate fertile and subfertile men when detected in viable (viable sDF), non-viable (non-viable sDF), and total spermatozoa (total sDF). We revealed sDF in 91 male partners of infertile couples and 71 fertile men (max 1 year from natural conception) with LiveTUNEL coupled to flow cytometry, able to reveal simultaneously DNA fragmentation and cell viability. We found that the three sDF parameters discriminated fertile and subfertile men with similar accuracy and independently from age and basal semen parameters: AUCs (area under the curves) (95% CI) were: 0.696 (0.615–0.776), p < 0.001 for total sDF; 0.718 (0.640–0.797), p < 0.001 for viable sDF; 0.760 (0.685–0.835), p < 0.001 for non-viable sDF. We also found that total and non-viable but not viable sDF significantly correlated to age and semen quality. In conclusion, the three sDF parameters similarly discriminated fertile and subfertile men. Viable spermatozoa with DNA fragmentation are likely cells able to fertilize the oocyte but failing to properly support subsequent embryo development. Non-viable sDF could be a sign of a subtler damage extended beyond the non-viable cells.

Positive effect of nutraceuticals on sperm DNA damage in selected infertile patients with idiopathic high sperm DNA fragmentation

BACKGROUND

The use of nutraceuticals to improve sperm parameters and male fertility is debatable, even if evidence suggests that selected infertile patients might benefit from their use. In particular, oxidative stress might play a role in idiopathic male infertility, leading to sperm membrane damage and high sperm DNA fragmentation (SDF). The aim of this study was to evaluate, in selected idiopathic infertile men with high SDF, the effect on sperm DNA damage and on standard semen parameters of a nutraceutical formulation containing myoinositol, alpha lipoic acid, coenzyme Q10, selenium, zinc and B vitamins.

METHODS

The study included 60 idiopathic infertile men with DNA fragmentation index (DFI) >20%. Semen analysis and DFI determination were assessed at baseline and after three months of nutraceutical treatment. Primary outcome was change in DFI.

RESULTS

Semen volume, sperm concentration, total sperm count, sperm motility and sperm morphology did not change after treatment. Instead, sperm vitality significantly increased (65.9±11.8% pre-treatment vs. 69.4±9.4% post-treatment, P<0.05) and DFI significantly decreased (33.5±10.1% pre-treatment vs. 26.8±8.7% post-treatment, P=0.0001) after treatment. The percentage of men with normal standard sperm parameters significantly increased (15% vs. 30%, P<0.05). The mean decrease in DFI was -6.7±1.4% and the percentage of men with DFI ≤30% after treatment was 75.0% compared to 48.3% pre-treatment (P<0.005). Higher pre-treatment DFI (and no other parameters) correlated with greater DFI reduction after treatment.

CONCLUSIONS

Nutraceuticals might be effective in idiopathic infertile men with high DFI to reduce SDF, increase sperm vitality and globally improve semen parameters.

Men With Inflammatory Bowel Disease: Sexual Function, Fertility, Medication Safety, and Prostate Cancer

Half of patients with inflammatory bowel disease (IBD) are men, yet less attention has been focused on their sexual issues despite higher rates of sexual dysfunction and infertility than the general population. Depression and IBD disease activity are the most consistently reported risk factor for sexual dysfunction among men with IBD. Methotrexate and sulfasalazine have been rarely associated with impotence. Sulfasalazine reversibly reduces male fertility. No other medications used in IBD significantly affect fertility in humans. There is no increase in adverse fetal outcomes among offspring of fathers with IBD. Patients with IBD seem to be at a higher risk for prostate cancer; therefore, screening as recommended for high-risk patients should be considered.

Standard Semen Parameters vs. Sperm Kinematics to Predict Sperm DNA Damage

Purpose

The aims of this study were to associate sperm kinematics and standard semen parameters with sperm DNA damage and to evaluate whether the addition of sperm kinematics improve the multivariable prediction of sperm DNA fragmentation compared to standard semen parameters alone.

Materials and Methods

We evaluated sperm kinematics, standard semen parameters, and DNA fragmentation index (DFI) in 122 men. Univariate and multivariate logistic regression models were fitted to evaluate the association of sperm kinematics and standard semen parameters with pathologically damaged sperm DNA (DFI≥26%), and receiver operating characteristics (ROC) curves were calculated for these models.

Results

On univariate analyses, average velocity, curvilinear velocity, straight-line velocity, straightness (STR), beat-cross frequency (BCF), and the percentage of progressive motile sperm cells (PPMS) were significantly associated with pathologically damaged sperm DNA. Likewise, among standard semen parameters, sperm concentration, progressive motility, normal morphology, and vitality were found to be linked with sperm DNA damage. On the multivariate analysis, vitality was the strongest predictor of pathologically damaged sperm DNA with an area under the ROC curve (AUROC) of 88.3%. Adding STR, BCF, and PPMS to vitality increased the AUROC to the significant extent of 91.5%.

Conclusions

Sperm vitality is the most accurate routine-based laboratory test for the prediction of pathologically damaged sperm DNA, but the addition of sperm kinematics increases its accuracy. Both standard semen parameters and sperm kinematics are complementary in predicting pathologically damaged sperm DNA, and might serve as a new tool to screen for fertile men.

The association of seminal leucocytes, interleukin-6 and interleukin-8 with sperm DNA fragmentation: A prospective study

The effect of seminal leucocytes on sperm DNA integrity has been discussed controversially in literatures. Moreover, the studies investigating the in vivo effect of pro-inflammatory cytokines interleukin-6 and interleukin-8 on sperm DNA fragmentation are scarce and inconsistent. The association of standard sperm parameters with sperm DNA fragmentation is also a matter of ongoing discussion. Hence, the aims of this study were, first, to evaluate the effect of seminal leucocytes, interleukin-6 and interleukin-8 on sperm DNA integrity and, second, to examine whether standard semen parameters are associated with sperm DNA fragmentation. Seminal leucocytes, interleukin-6, interleukin-8 and standard semen parameters, including total sperm number, sperm concentration, progressive motility, nonprogressive motility, immotility and normal morphology, were determined in 134 consecutive men. The concentrations of seminal leucocytes, interleukin-6 and interleukin-8, did not correlate with sperm DNA fragmentation. In contrast, total sperm number, sperm concentration, progressive motility, nonprogressive motility and normal morphology exhibited significant inverse correlations with sperm DNA fragmentation. Immotile spermatozoa were directly correlated with sperm DNA fragmentation. In conclusion, seminal leucocytes, interleukin-6 and interleukin-8, are not associated with sperm DNA fragmentation. Poor standard semen parameters are significantly related to the high levels of sperm DNA fragmentation.

Incidence of high sperm DNA fragmentation in a targeted population of subfertile men

Sperm DNA integrity is important for fertility, however the incidence of high levels of DNA fragmentation (DNA fragmentation index (DFI) >30%) is not well described. In 2011, our clinics implemented guidelines for sperm DNA fragmentation (SDF) testing based on risk factors using the sperm chromatin structure assay (SCSA). The aim of this retrospective study is to characterise SDF and associated factors (age, semen parameters, smoking status and BMI) for sub-fertile males (n = 1082) and sperm donors (n = 234). The average DFI was 12.1 ± 9.8%. The distribution of men with low, moderate and high SDF (<15, 15-30 and >30%) was 74.8%, 19.4% and 5.8%, respectively. Men with high DFI were older (45 ± 9.5 vs 38 ± 6.7) and had lower percentage of motile sperm (38.8 ± 16.1% vs 55.3 ± 15.8%) than men with normal DFI. Over 17% of the men in the quartile with the highest age and lowest motility had a high DFI (>30%), compared to a high DFI rate of 2-4% for the other 3 quartiles. Repeat testing following lifestyle interventions was available for 29 couples where the men had high initial DFI (35 ± 9.5%). Of these men, 71.4% had a decrease of DFI into the moderate or low range. This study shows that SDF testing can be targeted based on age and sperm motility, thereby reducing unnecessary testing. Furthermore, we provide evidence that lifestyle modifications can reduce DNA fragmentation in men with high DFI.

Intracytoplasmic sperm injection for male infertility and consequences for offspring

Intracytoplasmic sperm injection (ICSI) has become the most commonly used method of fertilization in assisted reproductive technology. The primary reasons for its popularity stem from its effectiveness, the standardization of the procedure, which means that it can easily be incorporated into the routine practice of fertility centres worldwide, and the fact that it can be used to treat virtually all forms of infertility. ICSI is the clear method of choice for overcoming untreatable severe male factor infertility, but its (over)use in other male and non-male factor infertility scenarios is not evidence-based. Despite all efforts to increase ICSI efficacy and safety through the application of advanced sperm retrieval and cryopreservation techniques, as well as methods for selecting sperm with better chromatin integrity, the overall pregnancy rates from infertile men remain suboptimal. Treating the underlying male infertility factor before ICSI seems to be a promising way to improve ICSI outcomes, but data remain limited. Information regarding the health of ICSI offspring has accumulated over the past 25 years, and there are reasons for concern as risks of congenital malformations, epigenetic disorders, chromosomal abnormalities, subfertility, cancer, delayed psychological and neurological development, and impaired cardiometabolic profile have been observed to be greater in infants born as a result of ICSI than in naturally conceived children. However, as subfertility probably influences the risk estimates, it remains to be determined to what extent the observed adverse outcomes are related to parental factors or associated with ICSI.

Flow cytometry in assessment of sperm integrity and functionality – a review

Spermatozoa must possess many attributes to fertilize an egg but few laboratory methods can assess all of these attributes simultaneously and objectively. Most laboratory methods used to assess the quality of semen in veterinary andrology can be inaccurate and time-consuming. Laboratory techniques which evaluate only one sperm attribute, often provide results that have a weak correlation with fertility. Therefore, semen used for artificial insemination should not be assessed based on the results of one method only but rather on the comprehensive results of several laboratory tests. Flow cytometry is a modern method of analysing diJ169fferent types of cells, including sperm cells. It is based on the scattering of light and fluorescence, the outcome of which yields results that are recorded and evaluated by computer technology which makes an objective assessment. Flow cytometry in combination with fluorescence microscopy and fluorescent probes provides a comprehensive, accurate, objective, and rapid analysis of the ejaculate. In a short time frame it allows us to test thousands of sperm for their structure and properties, even with a minimal amount of semen. This method enables the evaluation of several indicators simultaneously in a population of sperm as a whole or for each sperm individually. It informs us about the selected indicators of sperm quality in the sample by examining the membrane integrity, DNA, mitochondria, acrosome, oxidative stress, and other properties. Flow cytometry has become an important method of evaluating the functional and morphological properties of sperm and is used for research in veterinary science as well as for a routine assessment of the semen quality.

The Effect of Sperm DNA Fragmentation Index on the Outcome of Intrauterine Insemination and Intracytoplasmic Sperm Injection

CONTEXT

Elevated sperm DNA fragmentation index (DFI) is found to affect normal embryonic development, implantation and fetal development after intrauterine insemination (IUI), in vitro fertilization and intracytoplasmic sperm injection (ICSI). Estimation of DFI by terminal deoxynucleotidyl transferase-mediated fluorescent deoxy uridine nucleotide nick end labeling (TUNEL) assay was found to have a high predictive value for pregnancy after fertility treatments.

AIM

This study aims to find the effect of increased sperm DNA fragmentation by TUNEL assay on reproductive outcome after IUI and ICSI.

PRIMARY OBJECTIVE

To find the association of DFI and pregnancy rate in IUI and ICSI.

SECONDARY OBJECTIVES

To find the association of DFI with fertilization and implantation in ICSI. To find the association of DFI with miscarriage rate.

SETTINGS AND DESIGN

A prospective observational study performed at a tertiary care university teaching hospital.

SUBJECTS AND METHODS

105 male partners of infertile couple planned for IUI and ICSI underwent estimation of sperm-DFI by TUNEL assay. The treatment outcomes were compared between the DFI-positive (≥20%) and DFI-negative (<20%) groups.

STATISTICAL ANALYSIS USED

Statistical analysis was performed by SPSS version 17, Software. P < 0.05 was considered statistically significant.

RESULTS

The men with abnormal semen analysis were significantly higher in the DFI-positive group (77.15% vs. 22.85%). There was no significant difference in the pregnancy rate in IUI cycles (17.6% vs. 11.8%); but in the ICSI, the pregnancy rate was significantly reduced in the DFI-positive group (16.7% vs. 47.4%).

CONCLUSIONS

Elevated DFI significantly affects the pregnancy rate in ICSI cycles.

Utility and Predictive Value of Human Standard Semen Parameters and Sperm DNA Dispersion for Fertility Potential

Because the assessment of sperm DNA fragmentation (SDF) plays a key role in male fertility, our study was designed to find the relationships between SDF and standard semen parameters. The receiver operating characteristic (ROC) curve showed that 18% SDF is a prognostic parameter for discriminating between men with normal and abnormal standard semen parameters (n = 667). Men with > 18% SDF had significantly lower quality semen, a higher prevalence of abnormal semen characteristics, and a higher odds ratio for abnormal semen parameters compared to men with ≤ 18% SDF. An ROC analysis provided predictive values for age and semen parameters to distinguish between men with SDF > 18% and men with ≤ 18% SDF. SDF was positively correlated with male age and teratozoospermia index but negatively with sperm concentration, total number of spermatozoa, sperm morphology, progressive motility, and vitality. Our study shows that 18% SDF has a predictive value for distinguishing between men with normal and abnormal semen characteristics. Men with >18% SDF have a higher risk for abnormal semen parameters, while age and obtained semen parameters have a predictive value for SDF. There is a relationship between SDF and conventional sperm characteristics, and thus, SDF can be incorporated into male fertility assessment.

Use of testicular sperm for intracytoplasmic sperm injection in men with high sperm DNA fragmentation: a SWOT analysis

Spermatozoa retrieved from the testis of men with high levels of sperm DNA fragmentation (SDF) in the neat semen tend to have better DNA quality. Given the negative impact of SDF on the outcomes of Assisted Reproductive Technology (ART), an increased interest has emerged about the use of testicular sperm for intracytoplasmic sperm injection (Testi-ICSI). In this article, we used a SWOT (strengths, weaknesses, opportunities, and threats) analysis to summarize the advantages and drawbacks of this intervention. The rationale of Testi-ICSI is bypass posttesticular DNA fragmentation caused by oxidative stress during sperm transit through the epididymis. Hence, oocyte fertilization by genomically intact testicular spermatozoa may be optimized, thus increasing the chances of creating a normal embryonic genome and the likelihood of achieving a live birth, as recently demonstrated in men with high SDF. However, there is still limited evidence as regards the clinical efficacy of Testi-ICSI, thus creating opportunities for further confirmatory clinical research as well as investigation of Testi-ICSI in clinical scenarios other than high SDF. Furthermore, Testi-ICSI can be compared to other laboratory preparation methods for deselecting sperm with damaged DNA. At present, the available literature supports the use of testicular sperm when performing ICSI in infertile couples whose male partners have posttesticular SDF. Due to inherent risks of sperm retrieval, Testi-ICSI should be offered when less invasive treatments for alleviating DNA damage have failed. A call for continuous monitoring is nonetheless required concerning the health of generated offspring and the potential complications of sperm retrieval.

Semen Quality and Sperm DNA Integrity in Patients With Severe Active Inflammatory Bowel Disease and Effects of Tumour Necrosis Factor-alpha Inhibitors

BACKGROUND AND AIMS

The impact of severe inflammation on semen quality, including sperm DNA integrity, in men with inflammatory bowel disease [IBD] is unknown, as are the potential effects of anti-tumour necrosis factor-alpha [TNF-alpha] therapy. We investigated the influence of severe active IBD and anti-TNF-alpha treatment on semen quality.

METHODS

We prospectively included 20 patients admitted with severe active IBD. Further, 19 patients who initiated and 17 who stopped anti-TNF-alpha therapy were included. Semen samples were obtained during active disease, and on/off treatment. For paired comparisons, samples were collected not less than 3 months after achieving remission, after treatment initiation, or after treatment cessation. Sperm DNA Fragmentation Index [DFI], concentration, morphology, and motility were evaluated. Sex hormones and seminal plasma anti-TNF-alpha drug levels were measured.

RESULTS

In patients with severe disease, progressive sperm motility was impaired and increased significantly [from 28.4% to 37.4%, p = 0.045] during remission. There was no difference in DFI [12.5% versus 12.0%, p = 0.55], concentration [55.0 mill/ml versus 70.0 mill/ml, p = 0.39], or normal morphology [4.7% versus 5.1%, p = 0.51] in these patients. During active disease, testosterone was decreased, and normalised after obtaining remission. Patients who started anti-TNF-alpha therapy had a statistically significant, but clinically irrelevant, reduction in DFI after treatment initiation [12.8% versus 10.0%, p = 0.02]. All other semen parameters were unaffected by therapy. Anti-TNF-alpha drugs were excreted in negligible amounts in semen.

CONCLUSIONS

Severe active IBD reduces progressive sperm motility and testosterone levels, but sperm DNA integrity is unaffected by active disease. Anti-TNF-alpha therapy does not impair sperm quality.