Clinical correlates of the biological variation of sperm DNA fragmentation in infertile men attending an andrology outpatient clinic

Intra-individual changes in sperm DNA fragmentation levels over short and long time periods

PURPOSE

We aimed to examine the longitudinal, intra-personal changes in DNA fragmentation index (DFI) over time.

METHODS

Men who performed at least two DFI measurements (using sperm chromatin structure assay (SCSA) between 2003 and 2019 were included in this study and allocated to groups by time between DFI tests: < 1 year, 1-3 years, 3-5 years, and > 5 years. An analysis of DFI change over time according to age groups was additionally performed. Regression models were developed to predict changes in DFI with time.

RESULTS

Overall, 225 patients had two or more DFI measurements done at least a month apart (mean of 586.7± 710.0 days). The < 1 year (n = 124) and 1-3 years (n = 68) groups demonstrated decreased DFI levels, while an increase in DFI was shown in 3-5 years (n = 21) and more than 5 years (n = 12) groups - 7.1 ± 14.9%, - 4.5 ± 13.4%, + 3.2 ± 8.4%, and + 10.8 ± 18.0%, respectively, p < 0.001). This trend was similarly shown in age subgroups of under 40 years and 40-50 years at baseline DFI. Linear regression models showed that the factors predictive of DFI increase are baseline DFI and > 3 years between DFI tests.

CONCLUSION

This study shows that DFI, in men being investigated for infertility, initially decreases in the first 3 years of follow-up, and then increases over time with the highest increase occurring after 5 years interval (an average increase of 10.8%). Testing infertile men's DFI levels at first evaluation may contribute to personalized consult regarding future reproductive outcomes.

Intra-individual variation of sperm DNA fragmentation in the Human ejaculate

This retrospective study assessed the biological intra-individual variability of the percentage of sperm with DNA damage (SDF) observed in subsequent ejaculates of the same individual. Variation in SDF was analyzed using the Mean Signed Difference (MSD) statistic based on 131 individuals, comprising 333 ejaculates. Either two, three or four ejaculates were collected from each individual. With this cohort of individuals two main questions were addressed; (1) does the number of ejaculates analyzed influence the variability in the level of SDF associated with each individual? and (2) is the variability observed in SDF similar when individuals are ranked according to their level of SDF? Results showed that the variation observed in mean SDF was not different when 2, 3 or 4 ejaculates were analyzed; consequently, we suggest that the assessment of SDF based on two ejaculates is likely to be representative of the mean SDF expected for the individual. In parallel, it was determined that the variation in SDF increased as SDF increased; in individuals presenting with an SDF value of lower than 30% (potentially fertile), only 5% possessed levels of MSD that could be considered as variable as that presented by individuals presenting with a recurrent high SDF. Finally, we showed that a single assessment of SDF in individuals with medium SDF (20-30%) was less likely to be predictive of the SDF value in the next ejaculate, and therefore, less informative of the patient's SDF status.

Effect of chronic sleep deprivation on acrosomal integrity and functional parameters of murine sperm

OBJECTIVE

To evaluate the effect of chronic sleep deprivation on sperm function quality in mice.

DESIGN

Experimental study.

SETTING

Not applicable.

ANIMALS

Spermatozoa from twenty-four 10-week-old C57BL/6J male mice.

INTERVENTION(S)

The sleep deprivation group underwent gentle handling for 6 hours for 5 consecutive days. The mice in the sleep recovery group were allowed to sleep during the 24-hour period after the sleep deprivation protocol.

MAIN OUTCOME MEASURE(S)

After euthanasia, the spermatozoa were collected for analysis. Sperm motility was evaluated using computer-assisted sperm analyzer. Intracellular superoxide anion (O₂^-) activity, acrosome integrity, mitochondrial activity, and DNA fragmentation assays were conducted afterward.

RESULT(S)

Sleep deprivation and sleep recovery groups presented a lower percentage of spermatozoa with an intact acrosome, compared with the respective control groups. Regarding DNA fragmentation, a decreased proportion of spermatozoa with Comet I class intact DNA was observed in the sleep recovery group, compared with the recovery control group. Beat cross frequency was increased in the sleep recovery group.

CONCLUSION(S)

Sleep deprivation can reduce sperm quality, impairing acrosome integrity. Sleep recovery decreased DNA integrity and increased beat cross frequency.

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.

Variability in Sperm DNA Fragmentation in Men with Mild/Unexplained Subfertility in a Prospective Longitudinal Intrauterine Insemination Trial

The biological variability of semen and sperm DNA fragmentation (SDF) parameters in a longitudinal intrauterine insemination (IUI) trial over multiple IUI cycles was investigated. A TUNEL assay was used for SDF testing, both before and after density gradient centrifugation. A significant age effect was observed: while semen parameters deteriorated with advancing age, on average, higher SDF values were observed for older males. There was quite some variability observed for both semen and SDF variables. Using fertile threshold values, three patient categories were distinguished: those with a high SDF in all samples, those with low SDF in all samples and those who fluctuated between high and low during the whole IUI trial. Density gradient centrifugation increases SDF. However, the three patient categories react differently after semen processing. A large percentage of those with high SDF retain their high SDF even after gradient centrifugation. The SDF fluctuaters react with a high SDF after gradient centrifugation. The low SDF category, on the contrary, distributes itself evenly between the three categories after gradient centrifugation. SDF testing after semen processing might be indispensable for therapeutic purposes, probably influencing medical decision-making. In order to isolate fluctuaters, a second SDF testing might be advocated in certain cases. SDF after semen processing is indispensable for therapeutic management.

Reliability of the sperm chromatin dispersion assay to evaluate sperm deoxyribonucleic acid damage in men with infertility

OBJECTIVE

To investigate the intraindividual agreement of the sperm chromatin dispersion (SCD) assay results to assess sperm DNA fragmentation (SDF) in men with infertility.

DESIGN

Diagnostic test reliability study.

SETTING

Andrology laboratories.

PATIENT(S)

A total of 219 men with infertility.

INTERVENTION(S)

Sperm DNA fragmentation assessment in two ejaculates of the same subjects within a 3-month interval, using the SCD assay performed and analyzed by the same observers under similar testing conditions.

MAIN OUTCOME MEASURE(S)

Cohen's κ statistics to assess the degree of agreement between the pairs of results after converting the nominal SCD values into categorical data, that is, normal (<20%), intermediate (21%-29%), and high (≥30%) SDF rates. We also assessed the pairs of results using reliability measures for numerical variables (intraclass correlation coefficient for consistency using the two-way mixed-effects model and Bland-Altman plots).

RESULT(S)

The degree of agreement in classifying patients according to normal and pathological SDF classes was overall substantial (κ = 0.632; 95% confidence interval [CI], 0.546-0.718). A total of 76.7% of individuals were classified under the same class using paired ejaculates. The agreement rate was highest (approximately 80%) in ejaculates initially classified as either normal or high and lowest (approximately 60%) among those with intermediate SDF levels. The frequency of intermediate SDF ejaculates downgraded to normal or upgrade to high SDF classes in the second test was similar (approximately 20%). The intraclass correlation coefficient was 0.856 (95% CI, 0.812-0.887), and the mean difference between the pairs of observations was 0.80% (95% CI, -0.72 to 2.23), indicating no systematic difference between paired observations.

CONCLUSION(S)

Our study indicates a substantial intraindividual agreement of paired SCD assay results to classify men with infertility into three SDF categories: normal, intermediate, and high. The reliability of the SCD assay was adequate and exceeded 0.80 using two ejaculates analyzed within a 3-month interval under similar conditions. Although this evidence overall supports a single SCD test for patient classification using predefined SDF thresholds, particularly when the first test shows normal or high SDF levels, one in four men will have discordant values in paired ejaculates. Clinicians should be judicious when using SDF test results in decision-making.

Sperm DNA fragmentation testing: Summary evidence and clinical practice recommendations

We herein summarise the evidence concerning the impact of sperm DNA fragmentation in various clinical infertility scenarios and the advances on sperm DNA fragmentation tests. The collected evidence was used to formulate 41 recommendations. Of these, 13 recommendations concern technical aspects of sperm DNA fragmentation testing, including pre‐analytical information, clinical thresholds and interpretation of results. The remaining 28 recommendations relate to indications for sperm DNA fragmentation testing and clinical management. Clinical scenarios like varicocele, unexplained infertility, idiopathic infertility, recurrent pregnancy loss, intrauterine insemination, in vitro fertilisation/intracytoplasmic sperm injection, fertility counselling for men with infertility risk factors and sperm cryopreservation have been contemplated. The bulk evidence supporting the recommendations has increased in recent years, but it is still of moderate to low quality. This guideline provides clinicians with advice on best practices in sperm DNA fragmentation testing. Also, recommendations are provided on possible management strategies to overcome infertility related to sperm DNA fragmentation, based on the best available evidence. Lastly, we identified gaps in knowledge and opportunities for research and elaborated a list of recommendations to stimulate further investigation.

A Strengths-Weaknesses-Opportunities-Threats (SWOT) analysis on the clinical utility of sperm DNA fragmentation testing in specific male infertility scenarios

Background

Sperm DNA fragmentation (SDF) is recognized as a leading cause of male infertility because it can impair the paternal genome through distinct pathophysiological mechanisms. Current evidence supports SDF as a major factor in the pathophysiology of several conditions, including varicocele, unexplained infertility, assisted reproductive technology failure, and environmental lifestyle factors, although the mechanisms involved have not been fully described yet. Measurement of the levels of DNA fragmentation in semen provides valuable information on the integrity of paternal chromatin and may guide therapeutic strategies. A recently published clinical practice guideline (CPG) highlighted how to use the information provided by SDF testing in daily practice, which triggered a series of commentaries by leading infertility experts. These commentaries contained an abundance of information and conflicting views about the clinical utility of SDF testing, which underline the complex nature of SDF.

Methods

A search of papers published in response to the CPG entitled “Clinical utility of sperm DNA fragmentation testing: practice recommendations based on clinical scenarios” was performed within the Translational Andrology and Urology (TAU) website (http://tau.amegroups.com/). The start and end dates for the search were May 2017 and August 2017, respectively. Each commentary meeting our inclusion criteria was rated as “supportive without reservation”, “supportive with reservation”, “not supportive” or “neutral”. We recorded whether articles discussed either SDF characteristics as a laboratory test method or clinical scenarios, or both. Subsequently, we extracted the particulars from each commentary and utilized the ‘Strengths-Weaknesses-Opportunities-Threats’ (SWOT) analysis to understand the perceived advantages and drawbacks of SDF as a specialized sperm function method in clinical practice.

Results

Fifty-eight fertility experts from six continents and twenty-two countries contributed commentaries. Overall, participants (87.9%; n=51) were supportive of the recommendations provided by the CPG on the utility of SDF testing based on clinical scenarios. The majority of participants made explicit remarks about both the clinical scenarios and SDF assays’ characteristics. Among ‘not supportive’ and ‘supportive with reservation’ participants, 75% (n=30/40) and 77.5% (n=31/40) expressed concerns related to technical limitations of SDF testing methods and clinical utility of the test in one or more clinical scenarios discussed in the CPG, respectively. The SWOT analysis revealed that the CPG provides a reasonable evidence-based proposal for integration of SDF testing in the routine daily practice. It also uncovered gaps of knowledge and threats limiting the widespread application of SDF in everyday practice, thus allowing the identification of opportunities to further refine SDF testing and its clinical utility.

Conclusions

The understanding of the role of SDF in male infertility requires an in-depth analysis of the multifactorial pathophysiological processes and the theories involved. The SWOT analysis allowed an objective evaluation of CPG on the clinical utility of SDF testing based on clinical scenarios and its accompanying commentaries written by global experts in all possible angles. Implementation of SDF testing in the clinic may not only increase the outcome of ART but more importantly improve the health of both fathers to be and resulting offspring.

Sperm DNA damage measured by sperm chromatin structure assay in men with a history of undescended testes

The aim of this study was to compare sperm DNA damage between men with a history of congenital undescended testis (UDT) and men with a history of acquired UDT. A long-term follow-up study of men with previous UDT was performed. Fifty men with congenital UDT who had undergone orchiopexy at childhood age, 49 men with acquired UDT after a 'wait-and-see'-protocol (e.g. awaiting spontaneous descent until puberty and perform an orchiopexy in case of non-decent), and 22 healthy proven fertile men were included. The DNA fragmentation index (DFI) using sperm chromatin structure assay (SCSA) was used to express the level of sperm DNA damage. Decreased fertility potential was considered if DFI was above 30%. Sperm DNA damage was not statistically different between cases of congenital and acquired UDT. DFI was significantly more often >30% in the complete group of men with congenital UDT (9/50; 18%) and in the subgroup with bilateral congenital UDT (3/7; 43%) in comparison with the controls (none) (p-value 0.049 and 0.01, respectively). Age at orchiopexy in congenital UDT had no statistical effect on DNA damage. In men with acquired UDT, DFI did not statistically differ between those having undergone orchiopexy and those experiencing spontaneous descent. This study supports the hypothesis that UDT is a spectrum representing both congenital UDT and acquired UDT. Sperm DNA damage at adult age is not influenced by age at orchiopexy in congenital UDT cases and by orchiopexy or spontaneous descent in acquired UDT cases.

Morphometric comparison by the ISAS® CASA-DNAf system of two techniques for the evaluation of DNA fragmentation in human spermatozoa

DNA fragmentation has been shown to be one of the causes of male infertility, particularly related to repeated abortions, and different methods have been developed to analyze it. In the present study, two commercial kits based on the SCD technique (Halosperm ® and SDFA) were evaluated by the use of the DNA fragmentation module of the ISAS ® v1 CASA system. Seven semen samples from volunteers were analyzed. To compare the results between techniques, the Kruskal-Wallis test was used. Data were used for calculation of Principal Components (two PCs were obtained), and subsequent subpopulations were identified using the Halo, Halo/Core Ratio, and PC data. Results from both kits were significantly different (P < 0.001). In each case, four subpopulations were obtained, independently of the classification method used. The distribution of subpopulations differed depending on the kit used. From the PC data, a discriminant analysis matrix was obtained and a good a posteriori classification was obtained (97.1% for Halosperm and 96.6% for SDFA). The present results are the first approach on morphometric evaluation of DNA fragmentation from the SCD technique. This approach could be used for the future definition of a classification matrix surpassing the current subjective evaluation of this important sperm factor.

The evolution and refinements of varicocele surgery

Varicoceles had been recognized in clinical practice for over a century. Originally, these procedures were utilized for the management of pain but, since 1952, the repairs had been mostly for the treatment of male infertility. However, the diagnosis and treatment of varicoceles were controversial, because the pathophysiology was not clear, the entry criteria of the studies varied among centers, and there were few randomized clinical trials. Nevertheless, clinicians continued developing techniques for the correction of varicoceles, basic scientists continued investigations on the pathophysiology of varicoceles, and new outcome data from prospective randomized trials have appeared in the world's literature. Therefore, this special edition of the Asian Journal of Andrology was proposed to report much of the new information related to varicoceles and, as a specific part of this project, the present article was developed as a comprehensive review of the evolution and refinements of the corrective procedures.

Impact of extensive laparoscopic venous disconnection on the recurrence rate and sperm DNA quality in infertile varicocele patients

Introduction:

Although there are many literature examining the possible effects of varicocelectomy on classic semen parameters and recurrence rate, few published articles have examined the effect of conventional laparoscopic varicocelectomy on sperm DNA integrity.

Objectives:

The objective was to evaluate the effect of extensive laparoscopic venous disconnections on the recurrence rate and sperm DNA damage in varicocele patients.

Methods:

Totally, 54 patients with varicocele underwent extensive laparoscopic venous disconnections were assessed by clinical evaluation, duplex scan, semen analysis, and sperm DNA fragmentation assay before surgery and after 6 and 12 months following surgery.

Results:

No intra- or post-operative complications were observed and out of 54 patients preoperatively complained from varicocele 2 (3.7%) patients' have recurrence during the follow-up period for 12 months. Out of 54 patients complaining from male infertility, 14 patients success to get pregnancy after 6 months with pregnancy rates of 25.92% and 22 (40.74%) after 12 months, and 28 patients (51.85%) had a preoperative DNA fragmentation index (DFI) >30%, decreased following surgery below 30% in 19 (35.18%) patients after 6 months, and 11 (20.37%) after 12 months, and the percentage of sperm with DFI > 30% was significantly decreased after 6 and 12 months, respectively (38.4 ± 10.6 vs. 31.3 ± 12.4, [P < 0.001] at 6 months, and 22.9 ± 13.2, [P < 0.001] after 1-year). Other spermatic parameter was significantly improved.

Conclusions:

An extensive laparoscopic venous disconnection was significantly decreasing the recurrence rate, DFI and improving normal semen parameters and fertility.

Comparison of reproductive outcome in oligozoospermic men with high sperm DNA fragmentation undergoing intracytoplasmic sperm injection with ejaculated and testicular sperm

OBJECTIVE

To investigate the effectiveness of intracytoplasmic sperm injection (ICSI) using testicular sperm as a strategy to overcome infertility in men with high sperm DNA fragmentation (SDF).

DESIGN

Prospective, observational, cohort study.

SETTING

Private IVF centers.

PATIENT(S)

A total of 147 couples undergoing IVF-ICSI and day 3 fresh ETs whose male partner has oligozoospermia and high SDF.

INTERVENTION(S)

Sperm injections were carried out with ejaculated sperm (EJA-ICSI) or testicular sperm (TESTI-ICSI) retrieved by either testicular sperm extraction (TESE) or testicular sperm aspiration (TESA). SDF levels were reassessed on the day of oocyte retrieval in both ejaculated and testicular specimens.

MAIN OUTCOME MEASURE(S)

Percentage of testicular and ejaculated spermatozoa containing fragmented DNA (%DFI) and clinical pregnancy, miscarriage, and live-birth rates.

RESULT(S)

The %DFI in testicular sperm was 8.3%, compared with 40.7% in ejaculated sperm. For the TESTI-ICSI group versus the EJA-ICSI group, respectively, the clinical pregnancy rate was 51.9% and 40.2%, the miscarriage rate was 10.0% and 34.3%, and the live-birth rate was 46.7% and 26.4%.

CONCLUSION(S)

ICSI outcomes were significantly better in the group of men who had testicular sperm used for ICSI compared with those with ejaculated sperm. SDF was significantly lower in testicular specimens compared with ejaculated counterparts. Our results suggest that TESTI-ICSI is an effective option to overcome infertility when applied to selected men with oligozoospermia and high ejaculated SDF levels.

Sperm DNA fragmentation and standard semen parameters in algerian infertile male partners

Purpose

To date, standard semen parameters have been the only parameters investigated in sperm samples of infertile men in Algeria. We investigated, for the first time, semen parameters according to sperm DNA fragmentation (SDF) in these subjects.

Materials and Methods

SDF was determined by a validated sperm chromatin dispersion test in 26 infertile men. Patients were split into two groups according to the SDF level estimated by the DNA fragmentation index (DFI): the low fragmentation group (LFG; LFG with DFI ≤18%) and high fragmentation group (HFG; HFG with DFI >18%). The standard semen parameters were measured in both groups.

Results

We found that semen concentration and motility were negatively correlated with DFI (r=-0.65, r=-0.45, respectively; p<0.05), while morphology and semen volume were not correlated with it (r=0.24, r=-0.18, respectively; p>0.05). Comparison of the sperm concentration revealed that it was significantly higher in LFG than in HFG (37.57%±13.16% vs. 7.32%±3.59%, respectively; p<0.05), whereas no significant difference was observed regarding sperm motility and morphology.

Conclusions

Our findings suggest that SDF correlates well with both sperm motility and concentration but not with morphology. Thus, we conclude that SDF evaluation provides additional information regarding sperm quality, and should be used as a complementary test for assessing semen characteristics in infertile males.

Sperm nuclear DNA fragmentation rate is associated with differential protein expression and enriched functions in human seminal plasma

OBJECTIVE

To analyse the proteomic profile of seminal plasma with the aim of identifying the proteins and post-genomic pathways associated with sperm DNA fragmentation.

MATERIALS AND METHODS

A cross-sectional study including 89 subjects from a human reproduction service was carried out. All semen samples were assessed for sperm DNA fragmentation using a comet assay. Results from 60 sperm were analysed using Komet 6.0.1 software and the 'Olive tail moment' variable was used to stratify these into low and high sperm DNA fragmentation groups. Seminal plasma proteins from the two groups were pooled and used for proteomic analysis. Quantitative data were used for functional enrichment studies.

RESULTS

Seventy-two proteins were identified or quantified in seminal plasma. Of these, nine were differentially expressed in the low group and 21 in the high group. Forty-two proteins were conserved between these groups. Functional enrichment analysis indicated that sperm DNA fragmentation was related to functions such as lipoprotein particle remodelling and regulation, fatty acid binding and immune response. Proteins found exclusively in the low group may be involved in correcting spermatogenesis and/or improving sperm function. Proteins in the high group were associated with increased innate immune response, sperm motility and/or maturation and inhibition of mitochondrial apoptosis.

CONCLUSION

Protein expression and post-genomic pathways of seminal plasma differ according to the rate of sperm DNA integrity.

Significant improvement of sperm DNA quality after microsurgical repair of varicocele

Varicocele is currently the most common irregularity identified in males that is associated with impaired spermatogenesis. It primarily presents in the form of decreased sperm count and motility, abnormal morphology, and significantly increased sperm DNA fragmentation. Several studies have shown that surgical repair improves semen parameters and increases the odds of spontaneous pregnancy. However the exact effect of surgical repair treatment remains controversial. Therefore, the aim of our study was to evaluate the effectiveness of microsurgical repair by comparing common semen parameters and sperm DNA fragmentation index (DFI). We evaluated infertile men (n = 19) who underwent microsurgical subinguinal varicocelectomy for treatment of clinical varicocele before and 3 months after surgery. Normozoospermic men (n = 19) were considered as the normal control group. Semen parameters improved significantly after surgery when compared with that before surgery, but still significant differences with the normal control group were observed. In comparison, sperm DNA integrity improved significantly after surgery (percentage DFI decreased from 28.4 ± 15.6% before surgery to 22.4 ± 12.9%, at 3 months post surgery) to similar levels as the normal control group. These results suggest that microsurgical repair may be considered as a treatment option in infertile men with palpable varicocele.

Sperm DNA Fragmentation: Origin and Impact on Human Reproduction

Sperm DNA can be damaged due to a multitude of different noxae, which include disease, and occupational and environmental factors. Depending on the magnitude of the damage, such lesions may be repaired by the oocyte or the embryo. If this is not possible, a permanent damage can be manifested leading to mutations of the male genome. In cases where the oocyte or the embryo does not counter these damages to the male genome in terms of repair or an early abortion, sperm DNA damage and fragmentation can be a cause of numerous diseases including childhood cancer.

Accurate sperm morphology assessment predicts sperm function

Sperm morphology has been associated with in vitro as well as in vivo fertilisation. The study aimed to evaluate the possible relation between the percentage of spermatozoa with normal morphology and the following sperm functional assays: (i) zona-induced acrosome reaction (ZIAR); (ii) DNA integrity; (iii) chromatin condensation; (iv) sperm apoptosis; and (v) fertilisation rates. Regression analysis was employed to calculate the association between morphology and different functional tests. Normal sperm morphology correlated significantly with the percentages of live acrosome-reacted spermatozoa in the ZIAR (r = 0.518; P < 0.0001; n = 92), DNA integrity (r = -0.515; P = 0.0018; n = 34), CMA(3) -positive spermatozoa (r = -0.745; P < 0.0001; n = 92), sperm apoptosis (r = -0.395; P = 0.0206; n = 34) and necrosis (r = -0.545; P = 0.0009; n = 34). Negative correlations existed between for the acrosome reaction, and DNA integrity, while negative associations were recorded with the percentages of CMA(3) -positive spermatozoa, apoptotic and necrotic spermatozoa. Sperm morphology is related to sperm dysfunction such as poor chromatin condensation, acrosome reaction and DNA integrity. Negative and significant correlations existed between normal sperm morphology and chromatin condensation, the percentage of spermatozoa with abnormal DNA and spermatozoa with apoptotic activity. The authors do not regard sperm morphology as the only test for the diagnosis of male fertility, but sperm morphology can serve as a valuable indicator of underlying dysfunction.

Are varicoceles associated with increased deoxyribonucleic acid fragmentation?

OBJECTIVE

To perform a literature search on the association between varicocele and sperm DNA fragmentation.

DESIGN

Systematic review.

PATIENT(S)

Men with a varicocele and infertility.

INTERVENTION(S)

Varicocele repair.

MAIN OUTCOME MEASURE(S)

Does the presence of a varicocele increase seminal oxidative stress and sperm DNA fragmentation?

RESULT(S)

In men with a varicocele increased levels of reactive oxygen species and sperm DNA damage can be found. This is probably related to defective spermatogenesis in these patients. Seminal oxidative stress is believed to be the source of sperm DNA damage. Patients with a varicocele and oligospermia may also have a diminished seminal antioxidant capacity. After varicocele repair sperm DNA fragmentation decreases.

CONCLUSION(S)

Varicocele is associated with sperm DNA damage, and this sperm pathology may be secondary to varicocele-mediated oxidative stress. The beneficial effect of varicocelectomy on sperm DNA damage further supports the premise that varicocele may impair sperm DNA integrity.

Antioxidant therapy in male infertility: fact or fiction?

Infertile men have higher levels of semen reactive oxygen species (ROS) than do fertile men. High levels of semen ROS can cause sperm dysfunction, sperm DNA damage and reduced male reproductive potential. This observation has led clinicians to treat infertile men with antioxidant supplements. The purpose of this article is to discuss the rationale for antioxidant therapy in infertile men and to evaluate the data on the efficacy of dietary and in vitro antioxidant preparations on sperm function and DNA damage. To date, most clinical studies suggest that dietary antioxidant supplements are beneficial in terms of improving sperm function and DNA integrity. However, the exact mechanism of action of dietary antioxidants and the optimal dietary supplement have not been established. Moreover, most of the clinical studies are small and few have evaluated pregnancy rates. A beneficial effect of in vitro antioxidant supplements in protecting spermatozoa from exogenous oxidants has been demonstrated in most studies; however, the effect of these antioxidants in protecting sperm from endogenous ROS, gentle sperm processing and cryopreservation has not been established conclusively.

Motile sperm organelle morphology examination (MSOME): intervariation study of normal sperm and sperm with large nuclear vacuoles

BACKGROUND

Although the motile sperm organelle morphology examination (MSOME) was developed only as a selection criterion, its application as a method for classifying sperm morphology may represent an improvement in evaluation of semen quality, with potential clinical repercussions. The present study aimed to evaluate individual variations in the motile sperm organelle morphology examination (MSOME) analysis after a time interval.

METHODS

Two semen samples were obtained from 240 men from an unselected group of couples undergoing infertility investigation and treatment. Mean time interval between the two semen evaluations was 119+/-102 days. No clinical or surgical treatment was realized between the two observations. Spermatozoa were analyzed at greater than or equal to 8400x magnification by inverted microscope equipped with DIC/Nomarski differential interference contrast optics. At least 200 motile spermatozoa per semen sample were evaluated and percentages of normal spermatozoa and spermatozoa with large nuclear vacuoles (LNV/one or more vacuoles occupying>50% of the sperm nuclear area) were determined. A spermatozoon was classified as morphologically normal when it exhibited a normal nucleus (smooth, symmetric and oval nucleus, width 3.28+/-0.20 microm, length 4.75+/-0.20 microm/absence of vacuoles occupying>4% of nuclear area) as well as acrosome, post-acrosomal lamina, neck and tail, besides not presenting cytoplasm around the head. One examiner, blinded to subject identity, performed the entire study.

RESULTS

Mean percentages of morphologically normal and LNV spermatozoa were identical in the two MSOME analyses (1.6+/-2.2% vs. 1.6+/-2.1% P=0.83 and 25.2+/-19.2% vs. 26.1+/-19.0% P=0.31, respectively). Regression analysis between the two samples revealed significant positive correlation for morphologically normal and for LNV spermatozoa (r=0.57 95% CI:0.47-0.65 P<0.0001 and r=0.50 95% CI:0.38-0.58 P<0.0001, respectively).

CONCLUSIONS

The significant positive correlation and absence of differences between two sperm samples evaluated after a time interval with respect to normal morphology and LNV spermatozoa indicated that MSOME seems reliable (at least for these two specific sperm forms) for analyzing semen. The present result supports the future use of MSOME as a routine method for semen analysis.

Decreased sperm DNA fragmentation after surgical varicocelectomy is associated with increased pregnancy rate

PURPOSE

We prospectively evaluated changes in sperm chromatin structure in infertile patients before and after surgical repair of varicocele, and the impact on the pregnancy rate.

MATERIALS AND METHODS

Included in the study were 49 men with at least a 1-year history of infertility, a palpable varicocele and oligospermia. World Health Organization semen analysis and sperm DNA damage expressed as the DNA fragmentation index using the sperm chromatin structure assay were assessed preoperatively and postoperatively. Pregnancy (spontaneous and after assisted reproductive technique) was recorded 2 years after surgery.

RESULTS

Mean sperm count, sperm concentration and sperm progressive motility improved significantly after varicocelectomy from 18.3 x 10(6) to 44.4 x 10(6), 4.8 x 10(6)/ml to 14.3 x 10(6)/ml and 16.7% to 26.6%, respectively (p <0.001). The DNA fragmentation index decreased significantly after surgery from 35.2% to 30.2% (p = 0.019). When the definition of greater than 50% improvement in sperm concentration after varicocelectomy was applied, 31 of 49 patients (63%) responded to varicocelectomy. After varicocelectomy 37% of the couples conceived spontaneously and 24% achieved pregnancy with assisted reproductive technique. The mean postoperative DNA fragmentation index was significantly higher in couples who did not conceive spontaneously or with assisted reproductive technique (p = 0.033).

CONCLUSIONS

After varicocelectomy sperm parameters significantly improved and sperm DNA fragmentation was significantly decreased. Low DNA fragmentation index values are associated with a higher pregnancy rate (spontaneous and with assisted reproductive technique). We suggest that varicocelectomy should be considered in infertile men with palpable varicocele, abnormal semen analysis and no major female factors.

Increased sperm DNA fragmentation in patients with vasectomy reversal has no prognostic value for pregnancy rate

PURPOSE

We evaluated sperm DNA fragmentation in patients with vasectomy reversal and its prognostic value to determine spontaneous and assisted reproductive technique pregnancy rates.

MATERIALS AND METHODS

We prospectively assessed DNA fragmentation with the sperm chromatin structure assay in postoperative semen samples of 70 patients with vasectomy reversal. At a median +/- SD followup of 4.3 +/- 0.5 years pregnancy rates were recorded.

RESULTS

DNA fragmentation in patients with vasectomy reversal was significantly increased vs that in proven fertile controls (30.2% +/- 20.1% vs 15.3% +/- 5.4%, p <0.001). Significant negative correlations were found between DNA fragmentation index and total sperm count, progressive motility, total number of progressive sperm, normal morphology and sperm vitality (-0.325 <r <-0.805). The obstructive interval did not correlate with DNA fragmentation. The spontaneous pregnancy rate was 46%. Significantly higher log total progressive sperm motility (p = 0.021) and a trend toward lower female age (p = 0.064) were detected in the spontaneous vs the no pregnancy group. No association was found between DNA fragmentation and the pregnancy rate.

CONCLUSIONS

Increased DNA fragmentation is present in semen samples of men after vasectomy reversal vs fertile controls but DNA fragmentation is not associated with spontaneous or assisted reproductive technique pregnancy rates in these patients.

Sperm DNA damage: correlation to severity of semen abnormalities

OBJECTIVES

To analyze the relationship between DNA damage and standard semen parameters (SSP) in patients who present for fertility evaluation. Evaluation of male fertility includes assessment of the SSP and increasingly sperm DNA damage. However, the relationship between DNA damage and SSP remains controversial.

METHODS

Following Institutional Research Ethics Board approval, semen samples from 2586 unselected nonazoospermic patients were subjected to computer-assisted semen analysis and flow cytometry-based sperm DNA damage assessment expressed as the DNA fragmentation index.

RESULTS

Sperm DNA damage was significantly negatively correlated to sperm SSP (concentration, motility, and normal morphology) and positively correlated to patient's age. DNA damage increased in association with the number of abnormalities in SSP. Patients with oligoasthenoteratozoospermia had significantly higher DNA damage and more frequent DNA damage over 30% compared with normozoospermic patients and patients with abnormalities in 1 or 2 SSP.

CONCLUSIONS

Our results indicate that DNA damage is significantly correlated to SSP as well as age. In addition, the degree of DNA damage increases with the number of abnormal parameters in a sample and is most severe in patients with oligoasthenoteratozoospermia. Complex and possibly age-related mechanisms of DNA damage in human spermatozoa may be responsible for the strong relationship between SSP and DNA fragmentation index.

Correlation between DNA damage and sperm parameters: a prospective study of 1,633 patients

OBJECTIVE

To investigate DNA fragmentation by using terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling in relation to World Health Organization parameters and computer-aided sperm analysis (CASA) in sperm to determine the possibility of obtaining a correlation among CASA parameters, sperm morphology, and DNA fragmentation.

DESIGN

Sperm analysis according to World Health Organization parameters, terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) for sperm DNA fragmentation, and CASA for sperm movement. Prospective study.

SETTING

All the patients were under clinical management, consulting for hypofertility at a fertility center in France.

PATIENT(S)

One thousand six hundred thirty-three men who were referred for infertility investigation, including a complete sperm analysis.

INTERVENTION(S)

Sperm analysis and DNA damage testing.

MAIN OUTCOME MEASURE(S)

Sperm morphology, DNA fragmentation, and movement characteristics.

RESULT(S)

One third of the patients had a TUNEL rate of >30%. Analysis of the 21 semen parameters tested revealed that 7 of them were significantly correlated with the TUNEL results.

CONCLUSION(S)

World Health Organization sperm parameters and DNA damage are complementary, rather than strongly linked. This should be considered to more fully understand the paternal contribution in assisted reproductive technologies failures.

Associations between dietary patterns and semen quality in men undergoing IVF/ICSI treatment

BACKGROUND This study investigates whether dietary patterns, substantiated by biomarkers, are associated with semen quality. METHODS In 161 men of subfertile couples undergoing in vitro fertilization treatment in a tertiary referral clinic in Rotterdam, the Netherlands, we assessed nutrient intakes and performed principal component factor analysis to identify dietary patterns. Total homocysteine (tHcy), folate, vitamin B12 and B6 were measured in blood and seminal plasma. Semen quality was assessed by sperm volume, concentration, motility, morphology and DNA fragmentation index (DFI). Linear regression models analyzed associations between dietary patterns, biomarkers and sperm parameters, adjusted for age, body mass index (BMI), smoking, vitamins and varicocele. RESULTS The 'Health Conscious' dietary pattern shows high intakes of fruits, vegetables, fish and whole grains. The 'Traditional Dutch' dietary pattern is characterized by high intakes of meat, potatoes and whole grains and low intakes of beverages and sweets. The 'Health Conscious' diet was inversely correlated with tHcy in blood (beta = -0.07, P = 0.02) and seminal plasma (beta = -1.34, P = 0.02) and positively with vitamin B6 in blood (beta = 0.217, P = 0.01). An inverse association was demonstrated between the 'Health Conscious' diet and DFI (beta = -2.81, P = 0.05). The 'Traditional Dutch' diet was positively correlated with red blood cell folate (beta = 0.06, P = 0.04) and sperm concentration (beta = 13.25, P = 0.01). CONCLUSIONS The 'Health Conscious' and 'Traditional Dutch' dietary pattern seem to be associated with semen quality in men of subfertile couples.

Testicular spermatozoa have statistically significantly lower DNA damage compared with ejaculated spermatozoa in patients with unsuccessful oral antioxidant treatment

OBJECTIVE

To compare DNA damage in ejaculated and testicular spermatozoa in patients with previously unsuccessful oral antioxidant treatment.

DESIGN

Prospective clinical study.

SETTING

University-affiliated teaching hospital.

PATIENT(S)

Twelve men with persistently high sperm DNA damage.

INTERVENTION(S)

Evaluation of DNA damage of ejaculated and testicular spermatozoa by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) assay.

MAIN OUTCOME MEASURE(S)

The DNA damage of ejaculated spermatozoa compared with that of testicular spermatozoa, both samples collected on the day of intracytoplasmic sperm injection.

RESULT(S)

Ejaculated spermatozoa showed a threefold higher DNA damage when compared with testicular samples (39.7% +/- 14.8 vs. 13.3% +/- 7.3).

CONCLUSION(S)

Our results indicated that in patients with previously unsuccessful oral antioxidant treatment the retrieved testicular spermatozoa had a lower degree of DNA damage compared with ejaculated sperm collected on the same day.

Low folate in seminal plasma is associated with increased sperm DNA damage

OBJECTIVE

To determine associations between vitamin B status, homocysteine (tHcy), semen parameters, and sperm DNA damage.

DESIGN

Observational study.

SETTING

A tertiary referral fertility clinic.

PATIENT(S)

Two hundred fifty-one men of couples undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatment, with subgroups of fertile (n = 70) and subfertile men (n = 63) defined according to semen concentration and proven fertility.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The DNA fragmentation index (DFI) as marker of sperm DNA damage determined using the sperm chromatin structure assay (SCSA), and semen parameters assessed according to World Health Organization criteria; tHcy, folate, cobalamin, and pyridoxine concentrations determined in seminal plasma and blood.

RESULT(S)

In the total group of fertile and subfertile men, all biomarkers in blood were statistically significantly correlated with those in seminal plasma. No correlation was found between the biomarkers in blood and the semen parameters. In seminal plasma, both tHcy and cobalamin positively correlated with sperm count. Folate, cobalamin, and pyridoxine were inversely correlated with ejaculate volume. In fertile men, seminal plasma folate showed an inverse correlation with the DNA fragmentation index.

CONCLUSION(S)

Low concentrations of folate in seminal plasma may be detrimental for sperm DNA stability.

Evaluation of chromatin integrity of motile bovine spermatozoa capacitated in vitro

The efficiency of in vitro embryo production is highly variable amongst individual sires in cattle. To eliminate that this variability is not caused by sperm chromatin damage caused by separation or capacitacion, chromatin integrity was evaluated. Seventeen of AI bulls with good NRRs but variable embryo production efficiency were used. For each bull, motile spermatozoa were separated on a Percoll gradient, resuspended in IVF–TALP medium and capacitated with or incubated without heparin for 6 h. Samples before and after separation and after 3-h and 6-h capacitacion or incubation were evaluated by the Sperm Chromatin Structure Assay (SCSA) and the proportion of sperm with intact chromatin structure was calculated. Based on changes in the non-DFI-sperm proportion, the sires were categorized as DNA-unstable (DNA-us), DNA-stable (DNA-s) and DNA-most stable (DNA-ms) bulls (n = 3, n = 5 and n = 9, respectively). In DNA-us bulls, separation produced a significant increase of the mean non-DFI-sperm proportion (p ≤ 0.01), as compared with the value before separation. Capacitacion produced a significant decrease in the mean non-DFI-sperm proportion in H+ sperm (p ≤ 0.01). In DNA-s bulls, separation significantly increased the mean non-DFI-sperm proportion (p ≤ 0.01) but during capacitacion, the mean non-DFI-sperm proportion remained almost unchanged. In DNA-ms bulls, neither separation nor capacitacion had any effect on the mean non-DFI-sperm proportion. It can be concluded that, although separation and capacitacion may produce some changes in sperm chromatin integrity, these are not associated with different in vitro fertility of the bulls involved.