The clinical utility of sperm DNA integrity testing: a guideline

Sperm DNA fragmentation testing: a cross sectional survey on current practices of fertility specialists

Background

Sperm DNA fragmentation (SDF) testing has been recognized as a valuable tool in the evaluation of infertile men. Despite that, its routine use in clinical practice is still hampered by the lack of understanding of the specific clinical scenarios where SDF testing is most beneficial. The aim of this study was to investigate fertility specialists evaluation of infertility of SDF testing in the context of male infertility evaluation and assisted reproductive technology.

Methods

A questionnaire was developed to survey the major aspects of SDF testing and was mailed to specialists with demonstrated clinical experience in the field of infertility. A total of 65 professionals were invited to answer issues related to the utility of SDF testing, the testing methods they used, were the SDF cut-off values, and the cost of testing and the perceived drawbacks of the test results. Specific clinical scenarios were presented to assess whether or not participants would recommend SDF testing. The frequency of responses was analyzed.

Results

Forty-nine participants from 19 countries responded to the study questionnaire. SDF testing was commonly ordered by 39 (79.6%) respondents; while 10 (20.4%) did not order SDF testing during fertility evaluation. Terminal deoxynucleotidyl transferase nick end labelling (TUNEL) and sperm chromatin structure assay (SCSA) were most commonly utilized (30.6% for both), followed by sperm chromatin dispersion (SCD) (20.4%), single cell gel electrophoresis (Comet) (6.1%) and other methods (12.2%). SDF was most commonly requested in couples presenting with recurrent conventional in vitro fertilization (IVF) failure or pregnancy loss following conventional IVF (91.8%), followed by couples with recurrent first trimester natural pregnancy loss (NPL) and recurrent pregnancy loss (RPL) following intracytoplasmic sperm injection (ICSI) (85.7% for both). A 67.3% of respondents admitted that an SDF test result would affect their decision to utilize testicular instead of ejaculated sperm for ICSI. The reported mean ± standard deviation (SD) cost (USD) of SDF testing was 170.4±122.9. Cost (46.9%), poor validation (36.7%) and low precision (18.3%) were the most commonly reported drawbacks of SDF testing.

Conclusions

SDF testing is utilized in the evaluation of infertility patients by a majority of fertility specialists under specific clinical scenarios. Shortcomings, such as the presence of several SDF testing methods with different cut-off values and the test charges were some of the reasons hampering the routine use of SDF in the evaluation of infertile men.

Semen quality and pregnancy loss in a contemporary cohort of couples recruited before conception: data from the Longitudinal Investigation of Fertility and the Environment (LIFE) Study

OBJECTIVE

To study the relationship between semen quality and pregnancy loss in a cohort of couples attempting to conceive.

DESIGN

Observational prospective cohort.

SETTING

Not applicable.

PATIENT(S)

Three hundred and forty-four couples with a singleton pregnancy observed daily through 7 postconception weeks of gestation.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Association between semen quality and pregnancy loss.

RESULT(S)

Ninety-eight (28%) of the couples experienced a pregnancy loss after singleton pregnancy. No differences were observed in semen volume, sperm concentration, total sperm count, sperm viability, or sperm morphology (World Health Organization [WHO] and strict criteria) by couple's pregnancy loss status irrespective of whether they were analyzed continuously or as dichotomous variables per the WHO 5th edition semen criteria. A dichotomous DNA fragmentation measure of ≥30% was statistically significantly associated with pregnancy loss. No association was identified with other sperm morphometric or movement measures. Of the 70 couples who re-enrolled after a pregnancy loss, 14 experienced a second loss. Similar findings were identified when examining semen quality from couples with recurrent pregnancy loss.

CONCLUSION(S)

Although a few trends were identified (e.g., DNA fragmentation), general semen parameters seemed to have little relation with risk of pregnancy loss or recurrent pregnancy loss at the population level. However, given that 30% of pregnancies end in miscarriage and half the fetal genome is paternal in origin, the findings await corroboration.

TUNEL labeling with BrdUTP/anti-BrdUTP greatly underestimates the level of sperm DNA fragmentation in semen evaluation

Many studies have now confirmed that sperm DNA fragmentation (SDF) is associated with a poorer outcome of some forms of assisted reproduction technology. For this reason, SDF is an important parameter to evaluate in male fertility assessment. TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) assay coupled to flow cytometry is one of the most promising methods for SDF quantification. Several kits for the detection of DNA fragmentation are currently available on the market and all are recommended as equally appropriate to quantify SDF. In this work we compared for the first time the efficacy of two different types of TUNEL kits for SDF quantification: one using an indirect antibody-based labeling system (BrdUTP/fluorescein-anti-BrdUTP) and another using a direct labeling system (fluorescein-dUTP). We demonstrated that TUNEL indirect labeling system largely underestimates SDF when compared with the direct labeling, the differences ranging from 19.2% to 85.3% (p<0.05, n = 22). We observed that these differences were most pronounced among dead spermatozoa where indirect labeling stained 40.1% [23.6%, 58.2%] and the direct system 65.7% [36.5%, 90.9%] (n = 10, p<0.05). Interestingly, we found that both systems stained the living spermatozoa with the same efficiency. We showed that the differences are due to the steric hindrance of the antibody during its binding to the BrdUTP. Indeed, after sperm DNA decondensation, the percentages of TUNEL positivity increased significantly from 46.3% [31.8%, 61.7%] to 97.5% [96.1%, 98.8%] (p<0.05, n = 5). Our results are important for future use of TUNEL in clinical practice. Laboratories relying on the use of an antibody-based system heavily underestimate SDF, most particularly in infertile patients with reduced sperm motility. As a consequence, the kit using BrdUTP/fluorescein-anti-BrdUTP should not be recommended as a method to assay DNA damage in semen. This study represents one further step in the standardization of TUNEL among laboratories.

Concepts in diagnosis and therapy for male reproductive impairment

An accurate medical history and directed physical examination are essential in diagnosis of male infertility. We review the hormonal assessments and specific genetic analyses that are useful additional tests, and detail other evidence-based examinations that are available to help guide therapeutic strategies. By contrast with female infertility treatments-especially hormonal manipulations to stimulate or enhance oocyte production-spermatogenesis and sperm quality abnormalities are much more difficult to affect positively. In general, a healthy lifestyle can improve sperm quality. A few men have conditions in which evidence-based therapies can increase their chances for natural conception. In this second of two papers in The Lancet Diabetes and Endocrinology Series on male reproductive impairment, we examine the agreements and controversies that surround several of these conditions. When we are not able to cure, correct, or mitigate the cause of conditions such as severe oligozoospermia, non-remedial ductal obstruction, and absence of sperm fertilising ability, assisted reproductive technologies, such as in-vitro fertilisation (IVF) with intracytoplasmic sperm injection (ICSI), can be used as an adjunctive measure to allow for biological paternity. Not considered possible just two decades ago, azoospermia due to testicular failure, including 47,XXY (Klinefelter syndrome), is now treatable in approximately 50% of cases when combining surgical harvesting of testicular sperm and ICSI. Although genetic fatherhood is now possible for many men previously considered sterile, it is crucial to discover and abrogate causes as best possible, provide reliable and evidenced-based therapy, consider seriously the health and wellness of any offspring conceived, and always view infertility as a possible symptom of a more general or constitutional disease.

Magnetic-activated cell sorting before density gradient centrifugation improves recovery of high-quality spermatozoa

Recent studies have evaluated the use of magnetic-activated cell sorting (MACS) to reduce apoptotic spermatozoa and improve sperm quality. However, the efficiency of using MACS alone, before or after sperm processing by density gradient centrifugation (DGC) has not yet been established. The purpose of this study is to determine the optimal protocol of MACS in assisted reproduction techniques (ART). Thus, we compared sperm quality obtained by DGC alone (DGC), DGC followed by MACS (DGC-MACS), MACS followed by DGC (MACS-DGC), and MACS alone (MACS), and found that the combined methods (MACS-DGC and DGC-MACS) led to retrieval of less spermatozoa with fragmented DNA compared to the single protocols. However, MACS-DGC protocol led to a significantly higher percentage of spermatozoa with progressive motility and normal morphology than DGC-MACS protocol. These findings suggest the potential clinical value of using MACS-DGC to improve sperm quality in seminal preparation for ART.

FSH treatment in infertile males candidate to assisted reproduction improved sperm DNA fragmentation and pregnancy rate

The purpose of this study is to evaluate whether follicle-stimulating hormone treatment improves sperm DNA parameters and pregnancy outcome in infertile male candidates to in-vitro fertilization.Observational study in 166 infertile male partners of couples undergoing in-vitro fertilization. Eighty-four patients were receiving follicle-stimulating hormone treatment (cases) and 82 refused treatment (controls). Semen parameters, sexual hormones, and sperm nucleus (fluorescence in-situ hybridization, acridine orange, TUNEL, and γH2AX) were evaluated at baseline (T0) and after 3 months (T1), when all subjects underwent assisted reproduction techniques. Statistical analysis was performed by analysis of variance.Compared to baseline, cases showed significant improvements in seminal parameters and DNA fragmentation indexes after follicle-stimulating hormone therapy (all P < 0.05), whereas no changes were observed in controls. Within cases, follicle-stimulating hormone treatment allowed to perform intrauterine insemination in 35 patients with a pregnancy rate of 23.2 %. Intracytoplasmic sperm injection was performed in all controls and in 49 patients from cases, with pregnancy rates of 23.2 and 40.8 %, respectively (P < 0.05). After 3 months (T0 vs. T1) of follicle-stimulating hormone therapy, cases with positive outcome had reduced DNA fragmentation index and lower double strand breaks (P < 0.05 and P < 0.001 vs. negative outcome, respectively).In this observational study, we showed that follicle-stimulating hormone treatment improves sperm DNA fragmentation, which in turn leads to increased pregnancy rates in infertile males undergoing in-vitro fertilization. In particular, double strand breaks (measured with γH2AX test) emerged as the most sensible parameter to follicle-stimulating hormone treatment in predicting reproductive outcome.

A systematic review and meta-analysis to determine the effect of sperm DNA damage on in vitro fertilization and intracytoplasmic sperm injection outcome

Sperm DNA damage is prevalent among infertile men and is known to influence natural reproduction. However, the impact of sperm DNA damage on assisted reproduction outcomes remains controversial. Here, we conducted a meta-analysis of studies on sperm DNA damage (assessed by SCSA, TUNEL, SCD, or Comet assay) and clinical pregnancy after IVF and/or ICSI treatment from MEDLINE, EMBASE, and PUBMED database searches for this analysis. We identified 41 articles (with a total of 56 studies) including 16 IVF studies, 24 ICSI studies, and 16 mixed (IVF + ICSI) studies. These studies measured DNA damage (by one of four assays: 23 SCSA, 18 TUNEL, 8 SCD, and 7 Comet) and included a total of 8068 treatment cycles (3734 IVF, 2282 ICSI, and 2052 mixed IVF + ICSI). The combined OR of 1.68 (95% CI: 1.49–1.89; P < 0.0001) indicates that sperm DNA damage affects clinical pregnancy following IVF and/or ICSI treatment. In addition, the combined OR estimates of IVF (16 estimates, OR = 1.65; 95% CI: 1.34–2.04; P < 0.0001), ICSI (24 estimates, OR = 1.31; 95% CI: 1.08–1.59; P = 0.0068), and mixed IVF + ICSI studies (16 estimates, OR = 2.37; 95% CI: 1.89–2.97; P < 0.0001) were also statistically significant. There is sufficient evidence in the existing literature suggesting that sperm DNA damage has a negative effect on clinical pregnancy following IVF and/or ICSI treatment.

Sperm DNA damage and its role in IVF and ICSI

While the semen analysis has traditionally been relied upon to differentiate fertile and infertile men, its utility has been questioned in the current era of assisted reproductive technologies. The desire for more sophisticated diagnostic and predictive tools has led to increased use of sperm DNA damage in the management of male infertility. Despite the availability of numerous assays to measure sperm DNA damage, our understanding of the etiology, measurement, and clinical implications of sperm DNA damage remains incomplete. While the current evidence is fraught with heterogeneity that complicates attempts at comparison and meta-analysis, there does appear to be a role for sperm DNA damage in the development and maintenance of pregnancy in the era of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). However, as noted by the American Society for Reproductive Medicine, the routine and widespread use of sperm DNA damage testing is not yet supported. Further studies are needed to standardize the measurement of sperm DNA damage and to clarify the exact role of sperm DNA damage within the myriad of other male and female factors contributing to reproductive outcomes in IVF and ICSI.

Effect of sperm DNA fragmentation on clinical outcomes for Chinese couples undergoing in vitro fertilization or intracytoplasmic sperm injection

Objective

To investigate the effect of sperm DNA fragmentation on the fertilization rate, embryo development and pregnancy outcome of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) in a cohort of Chinese couples.

Methods

Infertile couples that had undergone assisted reproductive technology at our centre between January 2011 and December 2013 were included in this retrospective study. Fractions of prepared sperm samples were evaluated for sperm DNA fragmentation on the day of oocyte recovery.

Results

Of the 550 couples selected, 415 had undergone IVF and 135 ICSI. Sperm DNA fragmentation rate was significantly negatively correlated with the fertilization rate in the ICSI cycles but not the IVF cycles. No association was found between sperm DNA fragmentation and cleavage rate or good quality embryo formation rates in IVF or ICSI cycles. Receiver operating characteristic (ROC) curve analysis showed that the sperm DNA fragmentation rate was a statistically significant prognostic indicator of the clinical fertilization rate in ICSI cycles; a rate > 22.3% was associated with a lower fertilization rate following ICSI compared with a rate ≤ 22.3%.

Conclusions

High values of sperm DNA fragmentation were associated with a low fertilization rate following ICSI but were not associated with alterations in pregnancy or live birth rates in either ICSI or IVF in this cohort of Chinese couples.

Use of testicular sperm for ICSI in oligozoospermic couples: how far should we go?

In 1992 and subsequently, several reports indicated that ICSI was a successful technique to achieve clinical pregnancy and live birth using spermatozoa with severely impaired characteristics. The initial optimism over the ability of ICSI to overcome significant sperm abnormalities was later tempered by the findings of more recent publications suggesting that some sperm deficits may not be as effectively treated with ICSI. In search for effective treatment for couples with severe male factor, a number of small retrospective and prospective studies have reported high pregnancy and live birth rates using testicular sperm for men with necrozoospermia, cryptozoospermia and oligozoospermia with or without elevated sperm DNA damage. Although the data suggest that there may be some benefit in performing testicular sperm retrieval (TSR)-ICSI in select groups of non-azoospermic infertile men, there are potential risks involved with TSR. Clinicians should balance these risks prior to the recommendation of TSR-ICSI on the result of a semen analysis or sperm DNA test alone. Careful evaluation and management of male factor infertility is important. The use of TSR-ICSI in the absence of specific sperm DNA defects is still experimental.

A data-driven search for semen-related phenotypes in conception delay

Sperm count, morphology, and motility have been reported to be predictive of pregnancy, although with equivocal basis prompting some authors to question the prognostic value of semen analysis. To assess the utility of including semen quality data in predicting conception delay or requiring >6 cycles to become pregnant (referred to as conception delay), we utilized novel data-driven analytic techniques in a pre-conception cohort of couples prospectively followed up for time-to-pregnancy. The study cohort comprised 402 (80%) male partners who provided semen samples and had time-to-pregnancy information. Female partners used home pregnancy tests and recorded results in daily journals. Odds ratios (OR), false discovery rates, and 95% confidence intervals (CIs) for conception delay (time-to-pregnancy > 6 cycles) were estimated for 40 semen quality phenotypes comprising 35 semen quality endpoints and 5 closely related fecundity determinants (body mass index, time of contraception, lipids, cotinine and seminal white blood cells). Both traditional and strict sperm phenotype measures were associated with lower odds of conception delay. Specifically, for an increase in percent morphologically normal spermatozoa using traditional methods, we observed a 40% decrease in conception delay (OR = 0.6, 95% CI = 0.50, 0.81; p = 0.0003). Similarly, for an increase in strict criteria, we observed a 30% decrease in odds for conception delay (OR = 0.7, 95% CI = 0.52, 0.83; p = 0.001). On the other hand, an increase in percent coiled tail spermatozoa was associated with a 40% increase in the odds for conception delay (OR = 1.4, 95% CI = 1.12, 1.75; p = 0.003). However, our findings suggest that semen phenotypes have little predictive value of conception delay (area under the curve of 73%). In a multivariate model containing significant semen factors and traditional risk factors (i.e. age, body mass index, cotinine and ever having fathered a pregnancy), there was a modest improvement in prediction of conception delay (16% increase in area under the curve, p < 0.0002).

Reduced sperm DNA longevity is associated with an increased incidence of still born; evidence from a multi-ovulating sequential artificial insemination animal model

PURPOSE

Using a rabbit model, we assessed the influence of sperm DNA longevity on female reproductive outcomes.

METHODS

Semen was collected from 40 bucks, incubated at 38 °C for 24 h, and the rate of sperm DNA fragmentation (rSDF) was determined using the sperm chromatin dispersion assay. Males were allocated into high rSDF (>0.5 units of increase per hour) or low rSDF (<0.5 units of increase per hour) groups. High and low rSDF semen samples were sequentially artificially inseminated into the same doe to reduce female factor variability, and pregnancy outcomes were recorded.

RESULTS

While there was no difference in SDFs between rSDF groups immediately after collection (T0), differences were significant after 2 h of incubation; SDFs determined at collection and rSDF behaved as independent characters (Pearson correlation = 0.099; P = 0.542). Following artificial insemination, the rate of stillborn pups was significantly higher in does inseminated by males with a high rSDF (14/21) compared to those with low rSDF (15/6); (contingency χ(2) 5.19; p = 0.022). The risk of stillborn when low rSDF rabbits were used for insemination was 0.16, but increased to 0.36 when high rSDF animals were used (odds ratio = 2.85; 95 % confidence interval = 1.4-2.7).

CONCLUSION(S)

Dynamic assessment of SDF coupled with natural multiple ovulation, high fecundity of the rabbit and control over female factor influence, provided a useful experimental model to demonstrate the adverse effect of reduced sperm DNA longevity on reproductive outcome.

New insights in sperm biology: How benchside results in the search for molecular markers may help understand male infertility

The male factor is responsible for about 40% of couple infertility cases and such percentage is expected to increase in the future because of several likely factors including the presence of endocrine disruptors in the environment, changes in lifestyle habits and advanced couple aging. How such factors affect male fertility status, however, should be clarified. Most studies on male fertility status have focused on parameters analyzed using a spermiogram test, the primary diagnostic tool in the routine assessment of male infertility, which is, however, poorly predictive of both natural and medically assisted conception. For these reasons it is mandatory for the scientific community to identify new molecular markers to incorporate into the existing diagnostic tests of male fertility. Ideally, such markers would be detected in mature spermatozoa to avoid invasive procedures for the patient. This review summarizes the recent advancements in benchside approaches that appear most promising for the development of new diagnostic sperm fertility tests, or identification of therapeutic targets, and, illustrates their advantages and limits.

Use of selective serotonin reuptake inhibitors reduces fertility in men

Clinical review of the present data on the effects of selective serotonin reuptake inhibitors (SSRIs) on male fertility was the objective of the study. PubMed and Scopus were searched for publications in English or Danish and reviewed. Human trials, animal studies and in vitro studies were included. Use of SSRIs negatively affects semen parameters in most studies. In some studies, SSRIs are also shown to reduce DNA integrity. SSRIs can also delay ejaculation. Depression and anxiety can cause reduced libido, erectile dysfunction and delayed ejaculation as well. The use of SSRIs seems to reduce male fertility by affecting semen parameters, although most studies have a degree of confounding by indication caused by the underlying depression.

Assisted reproductive technologies for male subfertility

BACKGROUND

Intra-uterine insemination (IUI), in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI) are frequently used fertility treatments for couples with male subfertility. The use of these treatments has been subject of discussion. Knowledge on the effectiveness of fertility treatments for male subfertility with different grades of severity is limited. Possibly, couples are exposed to unnecessary or ineffective treatments on a large scale.

OBJECTIVES

To evaluate the effectiveness and safety of different fertility treatments (expectant management, timed intercourse (TI), IUI, IVF and ICSI) for couples whose subfertility appears to be due to abnormal sperm parameters.

SEARCH METHODS

We searched for all publications that described randomised controlled trials (RCTs) of the treatment for male subfertility. We searched the Cochrane Menstrual Disorders and Subfertility Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, PsycINFO and the National Research Register from inception to 14 April 2015, and web-based trial registers from January 1985 to April 2015. We applied no language restrictions. We checked all references in the identified trials and background papers and contacted authors to identify relevant published and unpublished data.

SELECTION CRITERIA

We included RCTs comparing different treatment options for male subfertility. These were expectant management, TI (with or without ovarian hyperstimulation (OH)), IUI (with or without OH), IVF and ICSI. We included only couples with abnormal sperm parameters.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected the studies, extracted data and assessed risk of bias. They resolved disagreements by discussion with the rest of the review authors. We performed statistical analyses in accordance with the guidelines for statistical analysis developed by The Cochrane Collaboration. The quality of the evidence was rated using the GRADE methods. Primary outcomes were live birth and ovarian hyperstimulation syndrome (OHSS) per couple randomised.

MAIN RESULTS

The review included 10 RCTs (757 couples). The quality of the evidence was low or very low for all comparisons. The main limitations in the evidence were failure to describe study methods, serious imprecision and inconsistency. IUI versus TI (five RCTs)Two RCTs compared IUI with TI in natural cycles. There were no data on live birth or OHSS. We found no evidence of a difference in pregnancy rates (2 RCTs, 62 couples: odds ratio (OR) 4.57, 95% confidence interval (CI) 0.21 to 102, very low quality evidence; there were no events in one of the studies).Three RCTs compared IUI with TI both in cycles with OH. We found no evidence of a difference in live birth rates (1 RCT, 81 couples: OR 0.89, 95% CI 0.30 to 2.59; low quality evidence) or pregnancy rates (3 RCTs, 202 couples: OR 1.51, 95% CI 0.74 to 3.07; I(2) = 11%, very low quality evidence). One RCT reported data on OHSS. None of the 62 women had OHSS.One RCT compared IUI in cycles with OH with TI in natural cycles. We found no evidence of a difference in live birth rates (1 RCT, 44 couples: OR 3.14, 95% CI 0.12 to 81.35; very low quality evidence). Data on OHSS were not available. IUI in cycles with OH versus IUI in natural cycles (five RCTs)We found no evidence of a difference in live birth rates (3 RCTs, 346 couples: OR 1.34, 95% CI 0.77 to 2.33; I(2) = 0%, very low quality evidence) and pregnancy rates (4 RCTs, 399 couples: OR 1.68, 95% CI 1.00 to 2.82; I(2) = 0%, very low quality evidence). There were no data on OHSS. IVF versus IUI in natural cycles or cycles with OH (two RCTs)We found no evidence of a difference in live birth rates between IVF versus IUI in natural cycles (1 RCT, 53 couples: OR 0.77, 95% CI 0.25 to 2.35; low quality evidence) or IVF versus IUI in cycles with OH (2 RCTs, 86 couples: OR 1.03, 95% CI 0.43 to 2.45; I(2) = 0%, very low quality evidence). One RCT reported data on OHSS. None of the women had OHSS.Overall, we found no evidence of a difference between any of the groups in rates of live birth, pregnancy or adverse events (multiple pregnancy, miscarriage). However, most of the evidence was very low quality.There were no studies on IUI in natural cycles versus TI in stimulated cycles, IVF versus TI, ICSI versus TI, ICSI versus IUI (with OH) or ICSI versus IVF.

AUTHORS' CONCLUSIONS

We found insufficient evidence to determine whether there was any difference in safety and effectiveness between different treatments for male subfertility. More research is needed.

Predictors of pregnancy outcome for infertile couples attending IVF and ICSI programmes

The purpose of this study was to evaluate the predictors of pregnancy outcome for infertile couples attending in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI) programmes. Infertile couples attending IVF or ICSI procedures were included in this study. Related data including semen parameters and male and female age and body mass index were collected and analysed. The main outcome was clinical pregnancy, defined as an ultrasound detection of foetal heartbeat 6 weeks after embryo transfer. A total of 1316 couples who underwent IVF and 266 who underwent ICSI were recruited for this study. A multivariate logistic regression with likelihood ratio test revealed the following predictors of pregnancy outcome: female age and sperm DNA fragmentation index (DFI) and acrosomal activity in IVF procedures (chi-square of likelihood ratio = 26.42, d.f. = 3, P < 0.005) and female age and DFI in ICSI procedures (chi-square of likelihood ratio = 18.88, d.f. = 2, P < 0.005). In conclusion, our study indicated that sperm DFI, female age and acrosomal levels have a significant effect on ART pregnancy outcome.

Sperm DNA fragmentation and mitochondrial membrane potential combined are better for predicting natural conception than standard sperm parameters

OBJECTIVE

To evaluate whether DNA fragmentation and/or mitochondrial membrane potential (MMP) predict natural conception better than standard sperm parameters.

DESIGN

Prospective cross-sectional study.

SETTING

University medical center.

PATIENT(S)

Eighty-five infertile and 51 fertile men.

INTERVENTION(S)

Assessment of sperm DNA fragmentation, MMP, and standard semen parameters over a 6- to 12-month observation period.

MAIN OUTCOME MEASURE(S)

Comparison between the results of DNA fragmentation, MMP, and standard sperm parameters alone or combined and achievement of natural conception.

RESULT(S)

Twenty-six of the 85 (31%) men from infertile couples conceived naturally. The median values of DNA fragmentation and MMP in the men who conceived within the observation period were similar to those in the fertile controls. Optimal threshold values of DNA fragmentation and MMP were 25% as determined by receiver operating characteristic analysis (area under the curve [AUC], 0.70; 95% confidence interval (CI) 0.58-0.82) and 62.5% (AUC, 0.68, 95% CI 0.56-0.80), respectively. The men in the infertile group with values of DNA fragmentation ≤25% and with MMP values ≥62.5% had significantly higher odds for conception (odds ratio [OR], 5.22; 95% CI 1.82-14.93] and OR, 4.67; 95% CI 1.74-12.5, respectively). Normal semen analysis alone had no predictive value for natural conception (OR, 1.84; 95% CI 0.67-5.07]). Both sperm function tests combined had significant odds for natural conception (OR, 8.24; 95% CI 2.91-23.33]), with a probability of 0.607 (60.7%) for both normal values and 0.158 (15.8%) for abnormal values.

CONCLUSION(S)

Sperm DNA fragmentation and MMP combined may be superior to standard semen parameters for the prediction of natural conception.

Urinary Phytoestrogens Are Associated with Subtle Indicators of Semen Quality among Male Partners of Couples Desiring Pregnancy

BACKGROUND

Phytoestrogens have been associated with subtle hormonal changes, although effects on male fecundity are largely unknown.

OBJECTIVE

We evaluated associations between male urinary phytoestrogen (isoflavone and lignan) concentrations and semen quality.

METHODS

This study was a prospective cohort study of 501 male partners of couples desiring pregnancy and discontinuing contraception. Each participant provided up to 2 semen samples that were analyzed for 35 semen quality endpoints the following day. Linear mixed-effects models were used to estimate associations between baseline urinary phytoestrogen concentrations and semen quality parameters, adjusted for age, body mass index (BMI), research site, and serum lipid and cotinine concentrations.

RESULTS

Most associations between urinary phytoestrogens and semen quality parameters were null. However, select individual phytoestrogens were associated with semen quality parameters, with associations dependent on the class of phytoestrogens and modified by BMI. Specifically, genistein and daidzein were associated with a lower percentage of normal sperm and increased abnormalities in semen morphology, with reduced associations observed as BMI increased (P < 0.05) [percentages (95% CIs) of normal morphology by WHO traditional criteria: genistein, main effect: -5.61% (-9.42%, -1.79%); interaction: 0.19% (0.06%, 0.31%) per log unit increase; daidzein, main effect: -5.35% (-9.36%, -1.34%); interaction: 0.18% (0.05%, 0.32%) per log unit increase]. Enterolactone was associated with fewer abnormalities in semen morphometry and morphology and decreased DNA fragmentation, with reduced associations observed as BMI increased (P < 0.05) [percentages (95% CIs) of abnormalities in the neck and midpiece: enterolactone, main effect: -3.35% (-6.51%, -0.19%); interaction: 0.11% (0.01%, 0.21%) per log unit increase].

CONCLUSIONS

These results suggest that male urinary phytoestrogen concentrations characteristic of the US population may be associated with subtle indicators of male fecundity and semen quality but were not associated with couple fecundity.

Sperm selection in natural conception: what can we learn from Mother Nature to improve assisted reproduction outcomes?

BACKGROUND

In natural conception only a few sperm cells reach the ampulla or the site of fertilization. This population is a selected group of cells since only motile cells can pass through cervical mucus and gain initial entry into the female reproductive tract. In animals, some studies indicate that the sperm selected by the reproductive tract and recovered from the uterus and the oviducts have higher fertilization rates but this is not a universal finding. Some species show less discrimination in sperm selection and abnormal sperm do arrive at the oviduct. In contrast, assisted reproductive technologies (ART) utilize a more random sperm population. In this review we contrast the journey of the spermatozoon in vivo and in vitro and discuss this in the context of developing new sperm preparation and selection techniques for ART.

METHODS

A review of the literature examining characteristics of the spermatozoa selected in vivo is compared with recent developments in in vitro selection and preparation methods. Contrasts and similarities are presented.

RESULTS AND CONCLUSIONS

New technologies are being developed to aid in the diagnosis, preparation and selection of spermatozoa in ART. To date progress has been frustrating and these methods have provided variable benefits in improving outcomes after ART. It is more likely that examining the mechanisms enforced by nature will provide valuable information in regard to sperm selection and preparation techniques in vitro. Identifying the properties of those spermatozoa which do reach the oviduct will also be important for the development of more effective tests of semen quality. In this review we examine the value of sperm selection to see how much guidance for ART can be gleaned from the natural selection processes in vivo.

Higher pregnancy rates using testicular sperm in men with severe oligospermia

OBJECTIVE

To evaluate assisted reproductive technology (ART) outcomes using testicular sperm in oligospermic men who previously failed to achieve paternity using TUNEL-positive ejaculated sperm.

DESIGN

Retrospective cohort.

SETTING

Academic medical center.

PATIENT(S)

Twenty-four oligospermic men who failed one or more ART cycles using ejaculated sperm with TUNEL-positive proportion >7%, and subsequently underwent microsurgical testicular sperm extraction (TESE).

INTERVENTION(S)

TESE followed by intracytoplasmic sperm injection (ICSI).

MAIN OUTCOME MEASURE(S)

TUNEL-positive level in ejaculated and testicular sperm; clinical pregnancy.

RESULT(S)

The mean TUNEL-positive level was 24.5% for ejaculated sperm, and 4.6% for testicular sperm. Clinical pregnancy was achieved in the first ART cycle with testicular sperm in 12 (50%) out of 24 couples. There was no statistically significant difference in maternal and paternal age, maternal gravity and parity, number of previous ART attempts, concentration or motility of retrieved sperm, number of oocytes retrieved, fertilization rate, or number of embryos transferred between couples who did and did not achieve pregnancy. No miscarriages occurred. All 12 pregnancies resulted in the delivery of healthy children.

CONCLUSION(S)

The percentage of TUNEL-positive cells is lower in testicular sperm for oligospermic men who have abnormal ejaculated sperm DNA fragmentation. The use of testicular sperm for ICSI was associated with a 50% pregnancy and live-birth rate for couples who had previously failed one or more IVF-ICSI cycles with ejaculated sperm. No other clinical predictors of successful pregnancies after the use of surgically retrieved sperm could be identified. In men with elevated TUNEL-positive ejaculated sperm and failed ART, TESE may be considered.

Unpacking the mysteries of sperm DNA fragmentation

Although it has been thirty years since publication of one of the most influential papers on the value of assessing sperm DNA damage, andrologists have yet to reach a general consensus about how to apply this seminal parameter to improve or predict reproductive outcomes. Studies that have attempted to establish a causal relationship between sperm DNA damage and pregnancy success have often resulted in conflicting findings, eroding the practitioner’s confidence to incorporate this phenomenon into their appraisal of fertility. In this review we have identified and answered ten important unresolved questions commonly asked by andrologists with respect to the relationship between sperm DNA damage and fertility. We answer questions ranging from a basic comprehension of biological mechanisms and external factors that contribute to increased levels of sperm DNA damage in the ejaculate to what type of DNA lesions we might be expect to occur and what are some of the consequences of DNA damage on early embryonic development. We also address some of the fundamental technical issues associated with the most appropriate measurement of sperm DNA damage and the need to attenuate the confounding impacts of iatrogenic damage. We conclude by asking whether it is possible to reduce elevated levels of sperm DNA damage therapeutically.

An integrated approach to male-factor subfertility: bridging the gap between fertility specialists trained in urology and gynaecology

Subfertile men and women are usually cared for by different clinicians, namely urologists and gynaecologists. While these doctors share each other's goals, they may not always appreciate the content or implications of their opposite number's clinical decisions; to some degree they may practice in "silos." We address this problem by reviewing the effectiveness of medical treatments for male factor subfertility in the context of female factors. The effectiveness of treatments for couples with male factor subfertility, other than IVF with ICSI, appears modest. However, data from randomized controlled trials suggest benefits from some treatments: clomiphene and tamoxifen for the male (common odds ratio for pregnancy [COR] 2.42; 95% CI 1.47 to 3.94), antioxidants (COR 4.18; 95% CI 2.65 to 6.59) and surgical management of a clinical varicocele (COR 2.39; 95% CI 1.56 to 3.66). Nevertheless, close attention to female age and the duration of subfertility help to avoid lost opportunity through delays in treatment when IVF with ICSI is indicated. Making treatment decisions squarely in the context of the couple's overall prognosis is key for optimal outcomes. Future trials of male fertility treatments should focus on pregnancy as the primary outcome, rather than less important surrogates such as sperm quality.

Concordance among sperm deoxyribonucleic acid integrity assays and semen parameters

OBJECTIVE

To assess the concordance of sperm chromatin structure assay (SCSA) results, epifluorescence TUNEL assay results, and standard semen parameters.

DESIGN

Prospective, observational study.

SETTING

Tertiary referral andrology clinic.

PATIENT(S)

A total of 212 men evaluated for subfertility by a single physician.

INTERVENTION(S)

Clinical history, physical examination, semen analysis, SCSA, and TUNEL assay.

MAIN OUTCOME MEASURE(S)

Spearman's rank correlation coefficients (r) between SCSA DNA fragmentation index (DFI), percentage TUNEL-positive sperm, and semen analysis parameters.

RESULT(S)

There was a positive correlation between SCSA DFI and TUNEL (r = 0.31), but the strength of this correlation was weaker than has previously been reported. The discordance rate between SCSA and TUNEL in classifying patients as normal or abnormal was 86 of 212 (40.6%). The SCSA DFI was moderately negatively correlated with sperm concentration and motility. The TUNEL results were unrelated to standard semen parameters.

CONCLUSION(S)

The SCSA DFI and percentage TUNEL-positive sperm are moderately correlated measures of sperm DNA integrity but yield different results in a large percentage of patients. The DFI is well-correlated with semen analysis parameters, whereas TUNEL is not. These data indicate that the SCSA and TUNEL assay measure different aspects of sperm DNA integrity and should not be used interchangeably.

Effects of increased paternal age on sperm quality, reproductive outcome and associated epigenetic risks to offspring

Over the last decade, there has been a significant increase in average paternal age when the first child is conceived, either due to increased life expectancy, widespread use of contraception, late marriages and other factors. While the effect of maternal ageing on fertilization and reproduction is well known and several studies have shown that women over 35 years have a higher risk of infertility, pregnancy complications, spontaneous abortion, congenital anomalies, and perinatal complications. The effect of paternal age on semen quality and reproductive function is controversial for several reasons. First, there is no universal definition for advanced paternal ageing. Secondly, the literature is full of studies with conflicting results, especially for the most common parameters tested. Advancing paternal age also has been associated with increased risk of genetic disease. Our exhaustive literature review has demonstrated negative effects on sperm quality and testicular functions with increasing paternal age. Epigenetics changes, DNA mutations along with chromosomal aneuploidies have been associated with increasing paternal age. In addition to increased risk of male infertility, paternal age has also been demonstrated to impact reproductive and fertility outcomes including a decrease in IVF/ICSI success rate and increasing rate of preterm birth. Increasing paternal age has shown to increase the incidence of different types of disorders like autism, schizophrenia, bipolar disorders, and childhood leukemia in the progeny. It is thereby essential to educate the infertile couples on the disturbing links between increased paternal age and rising disorders in their offspring, to better counsel them during their reproductive years.

Diagnostic evaluation of the infertile male: a committee opinion

The purpose of this ASRM Practice Committee report is to provide clinicians with principles and strategies for the evaluation of couples with male infertility problems. This revised document replaces the document of the same name, last published in 2012 (Fertil Steril 2012;98:294-301).

New genetic markers for male infertility

PURPOSE OF REVIEW

The purpose of this review is to highlight the most important advances in the field of genetics of male infertility, with particular attention to primary articles dealing with the identification of new genetic and epigenetic markers that could be translated into clinical practice in the near future.

RECENT FINDINGS

Copy number variations (CNVs) of the Y chromosome (gr/gr) deletions could already be included in the diagnostic workup of infertile men, although confirming studies are needed for CNVs on the X chromosome, as well for polymorphisms in some autosomal genes and telomere length in sperm. Methods need to be further standardized before sperm DNA analysis could be included in clinical practice, although they can help in defining some forms of idiopathic infertility. Epigenetic biomarkers are potentially important in elucidating the cause of idiopathic male infertility. Polymorphisms in FSHB/FSHR could be used in clinical practice to diagnose some forms of male infertility and as a pharmacogenetic marker for FSH treatment.

SUMMARY

New genetic causes and genetic risk factors have been identified in recent years and new technologies for genomic and postgenomic analyses (arrays, next-generation sequencing, proteomics, metabolomics, global methylome analysis and so on) are promising research fields. It is presumed that some of these genetic and epigenetic tests will be introduced in clinical practice in the near future.

Endocannabinoids and Reproductive Events in Health and Disease

The lasting research on the endocannabinoid system (ECS) has now provided solid and convincing evidence that proves the detrimental effects of recreational drug abuse (a growing habit among teenagers) on fertility. Endocannabinoids (eCBs) affect reproductive events from gametogenesis to fertilization, from embryo implantation to the final outcome of pregnancy and, thus, they have been proposed as suitable biomarkers to predict the reproductive potential of male and female gametes in clinical practice. Novel tools for reproductive medicine are highly sought after, and here we report the latest findings on the impact of the ECS on fertility, demonstrating how basic research can be translated into new medical strategies.

Perfluorochemicals and human semen quality: the LIFE study

BACKGROUND

The relation between persistent environmental chemicals and semen quality is evolving, although limited data exist for men recruited from general populations.

OBJECTIVES

We examined the relation between perfluorinated chemicals (PFCs) and semen quality among 501 male partners of couples planning pregnancy.

METHODS

Using population-based sampling strategies, we recruited 501 couples discontinuing contraception from two U.S. geographic regions from 2005 through 2009. Baseline interviews and anthropometric assessments were conducted, followed by blood collection for the quantification of seven serum PFCs (perfluorosulfonates, perfluorocarboxylates, and perfluorosulfonamides) using tandem mass spectrometry. Men collected a baseline semen sample and another approximately 1 month later. Semen samples were shipped with freezer packs, and analyses were performed on the day after collection. We used linear regression to estimate the difference in each semen parameter associated with a one unit increase in the natural log-transformed PFC concentration after adjusting for confounders and modeling repeated semen samples. Sensitivity analyses included optimal Box-Cox transformation of semen quality end points.

RESULTS

Six PFCs [2-(N-methyl-perfluorooctane sulfonamido) acetate (Me-PFOSA-AcOH), perfluorodecanoate (PFDeA), perfluorononanoate (PFNA), perfluorooctane sulfonamide (PFOSA), perfluorooctane sulfonate (PFOS), and perfluorooctanoic acid (PFOA)] were associated with 17 semen quality end points before Box-Cox transformation. PFOSA was associated with smaller sperm head area and perimeter, a lower percentage of DNA stainability, and a higher percentage of bicephalic and immature sperm. PFDeA, PFNA, PFOA, and PFOS were associated with a lower percentage of sperm with coiled tails.

CONCLUSIONS

Select PFCs were associated with certain semen end points, with the most significant associations observed for PFOSA but with results in varying directions.

Fragmentation of sperm DNA using the TUNEL method

OBJECTIVES

To establish the validity of the TUNEL assay in determining sperm DNA fragmentation, the relationship between the degree of fragmentation and the seminal parameters and the sample needed to conduct the test.

MATERIAL AND METHODS

We used semen samples from healthy fertile men (n=33), patients who consulted for infertility with a prescription for the TUNEL assay (n=77) and patients with intracytoplasmic sperm injection failure (n=20), analyzed according to the 2010 WHO. The TUNEL/propidium iodide test was performed by flow cytometry, on baseline and post-swim-up samples.

RESULTS

The cutoff value for the TUNEL assay (ROC curves) was 26%, with a sensitivity and specificity of 85% and 89%, respectively. The pre-swim-up and post-swim-up medians of the results from the TUNEL assay showed no significant differences (17.0% vs. 12.9%, respectively). However, 39.1% of the samples showed a difference greater than 15 in absolute value between the results of the baseline and post-swim-up TUNEL assays. The linear correlation study of the morphology, mobility and vitality using the post-swim-up TUNEL assay showed a greater correlation than preselection, with significant results (r: -0.394, P<.0001; r: -0.461, P<.0001; r: -0.526, P<.0001).

CONCLUSIONS

The TUNEL assay is a valid test for clinical use. DNA fragmentation is a factor independent from traditional semen tests. We found a greater susceptibility to damage generated in the laboratory procedures in the samples with lower quality. The sample of choice for evaluating DNA fragmentation will depend on whether the clinician is treating a natural or assisted fertilization.