Sperm head morphology is related to high deoxyribonucleic acid stainability assessed by sperm chromatin structure assay

A novel murine model mimicking male genital Neisseria species infection using Neisseria musculi†

With ~78 million cases yearly, the sexually transmitted bacterium Neisseria gonorrhoeae is an urgent threat to global public health due to continued emergence of antimicrobial resistance. In the male reproductive tract, untreated infections may cause permanent damage, poor sperm quality, and subsequently subfertility. Currently, few animal models exist for N. gonorrhoeae infection, which has strict human tropism, and available models have limited translatability to human disease. The absence of appropriate models inhibits the development of vital new diagnostics and treatments. However, the discovery of Neisseria musculi, a mouse oral cavity bacterium, offers much promise. This bacterium has already been used to develop an oral Neisseria infection model, but the feasibility of establishing urogenital gonococcal models is unexplored. We inoculated mice via the intrapenile route with N. musculi. We assessed bacterial burden throughout the male reproductive tract, the systemic and tissue-specific immune response 2-weeks postinfection, and the effect of infection on sperm health. Neisseria musculi was found in penis (2/5) and vas deferens (3/5) tissues. Infection altered immune cell counts: CD19+ (spleen, lymph node, penis), F4/80+ (spleen, lymph node, epididymus), and Gr1+ (penis) compared with noninfected mice. This culminated in sperm from infected mice having poor viability, motility, and morphology. We hypothesize that in the absence of testis infection, infection and inflammation in other reproductive is sufficient to damage sperm quality. Many results herein are consistent with outcomes of gonorrhoea infection, indicating the potential of this model as a tool for enhancing the understanding of Neisseria infections of the human male reproductive tract.

Associations between Sperm Epigenetic Age and Semen Parameters: An Evaluation of Clinical and Non-Clinical Cohorts

The well-documented relationship between chronological age and the sperm methylome has allowed for the construction of epigenetic clocks that estimate the biological age of sperm based on DNA methylation, which we previously termed sperm epigenetic age (SEA). Our lab demonstrated that SEA is positively associated with the time taken to achieve pregnancy; however, its relationship with semen parameters is unknown. A total of 379 men from the Longitudinal Investigation of Fertility and Environment (LIFE) study, a non-clinical cohort, and 192 men seeking fertility treatment from the Sperm Environmental Epigenetics and Development Study (SEEDS) were included in the study. Semen analyses were conducted for both cohorts, and SEA was previously generated using a machine learning algorithm and DNA methylation array data. Association analyses were conducted via multivariable linear regression models adjusting for BMI and smoking status. We found that SEA was not associated with standard semen characteristics in SEEDS and LIFE cohorts. However, SEA was significantly associated with higher sperm head length and perimeter, the presence of pyriform and tapered sperm, and lower sperm elongation factor in the LIFE study (p < 0.05). Based on our results, SEA is mostly associated with defects in sperm head morphological factors that are less commonly evaluated during male infertility assessments. SEA shows promise to be an independent biomarker of sperm quality to assess male fecundity.

A Preliminary Study on the Evaluation of Human Sperm Head Morphology with a Domestic Digital Holographic Image System

The head of sperm was imaged with domestic digital holographic microscopy (DHM), and then the quantitative three-dimensional size information of normal sperm and teratozoospermic sperm was compared and analyzed. DHM sperm imaging and repeated quantitative evaluation were used to determine the morphology of the sperm head in two patients with teratozoospermia and four volunteers with normal semen parameters. Sixty and 139 sperm of teratozoospermia patients and normal people were photographed by digital hologram, respectively. The differences in head height and width were compared and statistically analyzed. The sperm head height of the teratozoospermia group was 3.06 ± 1.66 μm, which was significantly lower than that of the normal sperm group (4.54 ± 1.60 μm, p < 0.01), but there was no significant difference in the head width between the two groups. Compared with the traditional two-dimensional optical microscope observation method, the DHM system can provide three-dimensional quantitative information for the sperm head and thus may help in the comprehensive clinical evaluation of the sperm head structure.

Impaired semen quality, an increase of sperm morphological defects and DNA fragmentation associated with environmental pollution in urban population of young men from Western Siberia, Russia

Poor sperm morphology and an elevated DNA fragmentation level are considered to be related to spermiogenesis malfunctions as a result of genetic mutations and effects of environmental factors, including industrial pollution. Standardized cross-sectional population studies of sperm morphology defects and sperm DNA fragmentation, especially in regions with increased environmental pollution may be helpful to investigate an influence of industrial pollution and other population-related factors on spermiogenesis process. The aim of present study was to estimate an influence industrial pollution on sperm morphogenesis and sperm DNA fragmentation in men from the general population of the Western Siberia. The Novosibirsk and Kemerovo cities are located to same climatic conditions in Western Siberia but the Kemerovo city is characterized by increased environmental pollution especially by particulate matter (PM). The male volunteers living in Novosibirsk (n = 278) and Kemerovo (n = 258) were enrolled. Percentages of sperm morphological defects are counted after staining native ejaculate smears by Diff-Quick kits. DNA fragmentation was estimated by a SCSA technique. The residents of Kemerovo were characterized by lowered sperm count and sperm motility, elevated DNA fragmentation, poor sperm morphology and increased incidence of morphological effects of head (pyriform, elongated, round, abnormal acrosome and vacuolated chromatine), asymmetrical neck insertion and excess residual cytoplasm. Moreover, elevated DNA fragmentation was associated with lowered sperm count, sperm motility and increased percentages of several sperm morphology defects, with the place of residence affecting the relationships between conventional semen parameters, sperm morphology and DNA fragmentations. Our study suggests that excessive sperm head elongation and impaired acrosome formation can contribute to sperm morphology deterioration in men from polluted areas. Regional features in the relationships between sperm morphology, sperm count and DNA fragmentation were shown, suggesting an importance of studying sperm morphology pattern in men from different regions.

Semen quality and sperm DNA integrity in city policemen exposed to polluted air in an urban industrial agglomeration

BACKGROUND

We examined sperm quality in a cohort of city policemen in Ostrava at the end of a period with high concentrations of air pollutants (winter) and in the same cohort at the end of a relatively low exposure period (summer).

METHODS

The study group was comprised of 54 nonsmoking city policemen living and working in Ostrava, Czech Republic. Average daily air-pollutant concentrations recorded by stationary monitoring for 90 days preceding the collection of semen samples were evaluated for different city districts of Ostrava. Standard semen parameters were assessed according to the guidelines of the World Health Organization (2010). The parameters were semen volume, sperm concentration, sperm morphology, sperm motility, acrosome reaction and sperm plasma membrane integrity. Sperm DNA damage was analysed by the sperm chromatin structure assay (SCSA). Sperm motion characteristics were determined by Computer Assisted Semen Analysis (CASA).

RESULTS

The concentrations of all monitored pollutants (particulate matter, sulphur dioxide, nitrogen oxides, carbon monoxide, benzo[a]pyrene, benzene) were significantly increased during winter (p < 0.001), except for ozone, the concentration of which was significantly higher during summer. Sperm volume, concentration, % vitality, % sperm morphology (normal form) and % acrosome-intact sperm did not differ significantly between the monitoring periods. The percentages of total motility and progressive motility were significantly higher in March, i.e. at the end of winter (p = 0.001). However, CASA testing showed differences in sperm motion kinetics between spring and autumn samples. In the spring samples, we found a significantly lower % of straightness (p = 0.044) and the length of straight-line path (p = 0.01), while linearity and straight-line velocity were near the borderline value (p = 0.064; p = 0.054, respectively). As compared to summer, high exposure to air pollution during winter significantly increased the extent of sperm chromatin integrity damage (median 22.6 vs. 18.6%) (p = 0.003) and the proportion of immature spermatozoa (median 11.2 vs. 9.9%, p = 0.001). Sperm DNA damage negatively correlated with total motility and progressive motility (r = -0.611, -0.299; p < 0.001). The negative correlation with vitality, normal morphology and acrosome-intact sperm (r = -0.522, -0.550 and -0.511, respectively) was also significant (p < 0.001).

CONCLUSION

The examination of the same cohort of city policemen at the end of a period of high air pollution and at the end of relatively low exposure reduced the effects of age, different lifestyles, different occupational exposures, localities and genetic polymorphism on sperm quality impairment associated with air pollution. This study did not demonstrate impaired standard semen parameters in association with exposure. It was shown that sperm chromatin damage and the percentage of immature sperm were highly sensitive to air pollution.

Quantitative selection of single human sperm with high DNA integrity for intracytoplasmic sperm injection

OBJECTIVE

To study at the single-cell level whether a sperm's motility and morphology parameters reflect its DNA integrity, and to establish a set of quantitative criteria for selecting single sperm with high DNA integrity.

DESIGN

Prospective study.

SETTING

In vitro fertilization center and university laboratories.

PATIENT(S)

Male patients undergoing infertility treatments.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The motility and morphology parameters of each sperm were measured with the use of computer vision algorithms. The sperm was then aspirated and transferred for DNA fragmentation measurement by single-cell gel electrophoresis (comet assay).

RESULT(S)

We adapted the World Health Organization criteria, which were originally defined for semen analysis, and established a set of quantitative criteria for single-sperm selection in intracytoplasmic sperm injection. Sperm satisfying the criteria had significantly lower DNA fragmentation levels than the sample population. Both normal motility and normal morphology were required for a sperm to have low DNA fragmentation. The quantitative criteria were integrated into a software program for sperm selection. In blind tests in which our software and three embryologists selected sperm from the same patient samples, our software outperformed the embryologists and selected sperm with the highest DNA integrity.

CONCLUSION(S)

At the single-cell level, a sperm's motility and morphology parameters reflect its DNA integrity. The developed technique and criteria hold the potential to mitigate the risk factor of sperm DNA fragmentation in intracytoplasmic sperm injection.

Sperm Selection Technology in ART

Intracytoplasmic sperm injection (ICSI) is a commonly used in vitro fertilization technique. Selection of sperm for injection is currently done using subjective assessment of morphology, which may not accurately identify the best-quality sperm. Hyaluronic acid receptors on sperm plasma membranes are a marker of maturity, and sperms which are capable of binding immobilized hyaluronic acid in vitro are of higher quality. This can be used as an advanced sperm selection technique to choose sperm for ICSI, termed physiological ICSI (PICSI). Several studies reported improved fertility treatment outcomes when using PICSI compared with conventional ICSI; however, the majority of studies are underpowered. Recently, a large, multicenter, randomized controlled trial, known as the Hyaluronic Acid Binding Sperm Selection (HABSelect) trial, found a significant reduction in miscarriage rates with PICSI, but no significant effect on live birth rate. There are still many avenues through which PICSI may provide an advantage, subject to confirmation by future research, such as improved long-term health of offspring. Other advanced sperm selection techniques include intracytoplasmic morphologically selected sperm injection, magnetic-activated cell sorting, and Zeta potential sperm selection; however, the most recent Cochrane review concluded that there is currently insufficient evidence to ascertain whether these techniques improve clinical outcomes, such as live birth rates.

DNA fragmentation of sperm: a radical examination of the contribution of oxidative stress and age in 16 945 semen samples

STUDY QUESTION

What is the relationship between sperm DNA fragmentation and oxidative stress (OS) with increasing male age?

SUMMARY ANSWER

Sperm DNA fragmentation increases with age and is likely related to both defective spermatogenesis and increasing OS levels.

WHAT IS KNOWN ALREADY

Sperm quality declines with age. The presence of DNA damage in a high fraction of spermatozoa from a raw semen sample is associated with lower male fertility in natural conception and intrauterine insemination.

STUDY DESIGN, SIZE, DURATION

A retrospective cohort study of 16 945 semen samples analysed at a single reference laboratory between January 2010 and December 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All males were undergoing an infertility evaluation. The cohort was divided into seven age categories: <30, 30-34, 35-39, 40-44, 45-49, 50 to <54 and ≥55 years. The mean age was 37.6 years (SD 6.8). Sperm DNA fragmentation index (DFI) and high DNA stainability (HDS) were calculated using flow cytometry. OS levels were measured using the oxidative stress adducts (OSA) test, by spectrophotometry. ANOVA with weighted polynomial contrast analysis was used to evaluate trends for DFI, OSA and HDS values across age categories.

MAIN RESULTS AND THE ROLE OF CHANCE

Mean DFI significantly increased across all age groups (Ptrend < 0.001). OSA was lowest in patients <30 years old (mean 3.6, SD 1.0) and also increased as age increased (Ptrend < 0.001). There was a statistically significant difference between age groups for each of the three parameters (P < 0.001). There was a significant linear trend for DFI, OSA and HDS across the seven age categories (P < 0.001). Among patients with high DFI, there was a decreasing age-dependent trend in the patients observed with high OSA (P < 0.001).

LIMITATIONS, REASONS FOR CAUTION

This is a retrospective study. All males included in the study were undergoing a work-up for infertility and may not be representative of a fertile population. Additional patient demographics and clinical data were not available.

WIDER IMPLICATIONS OF THE FINDINGS

DNA and/or oxidative damage in sperm may be just as important to understand as the chromosomal aberrations that are carried in the oocyte. Further studies are needed to evaluate the effect of advancing paternal age on the male genome and, ultimately, on the health of the offspring.

STUDY FUNDING/COMPETING INTEREST(S)

No funding was obtained for this study. V.D. is an employee of Reprosource/Quest Diagnostics. D.S. reports he was a Scientific Advisor to Cooper Surgical.

TRIAL REGISTRATION NUMBER

N/A.

Automated motility and morphology measurement of live spermatozoa

BACKGROUND

Automated sperm analysis has wide applications in infertility diagnosis. Existing systems are not able to measure sperm count and both motility and morphology of individual live spermatozoa. Morphology measurement requires invasive staining, making the spermatozoa after morphology measurement not applicable to infertility treatment.

OBJECTIVE

To evaluate the reproducibility and reliability of automated measurement of individual live sperm's motility and morphology.

MATERIALS AND METHODS

Fresh semen samples were obtained from twenty male partners attending for fertility investigations. The system firstly measured motility for all the spermatozoa within the field of view under a low magnification (20×), then a spermatozoa of interest is selected by the user and automatically relocated by the system after switching to a high magnification (100×) for morphology measurement. Reproducibility of sperm measurements was evaluated by intraclass correlation coefficients on consecutive measurement. Reliability of motility and morphology measurement was evaluated by tracking error rate and limits of agreement, respectively, with manual measurement as benchmark.

RESULTS

Measurement of all motility and morphology parameters had intraclass correlation coefficients higher than 0.94. Sperm motility measurement had a tracking error rate of 2.1%. Limit of agreement analysis indicated that automated measurement and manual measurement of sperm morphology were interchangeable. Automated measurement of all morphology parameters was not statistically different from manual measurement, as confirmed by the paired sample t test.

DISCUSSION

Automated motility and morphology measurement of single sperm revealed high reproducibility and reliability. The system also achieved a high efficiency for motility and morphology measurement. In addition to the intracytoplasmic sperm injection (ICSI) samples with polyvinylpyrrolidone (PVP), the developed sperm measurement technique is also effective for analyzing semen and washed samples. The system provides a valuable tool for quantitative measurement and selection of single spermatozoa for ICSI. It can also be used for sperm motility and morphology analysis in andrology laboratories.

Male age is associated with sperm DNA/chromatin integrity

The diagnosis of sperm DNA integrity is increasingly recognized as being crucial to inform the clinical course in infertile couples. An internationally accepted sperm DNA fragmentation assay that determines the proportion of sperm and degree of broken sperm nuclear DNA with recognised clinical thresholds for identifying men at risk of infertility is the Sperm Chromatin Structure Assay (SCSA^®). In this study, SCSA^® test was utilised to evaluate the relevance of male age on sperm DNA quality in total of 6881 males of Indian origin. Analysis of proportions of DNA fragmentation index (%DFI) and high DNA stainability (%HDS) was performed based on four groups (<35, 35-40, 40-45, and >45 years of age). The impact of increasing male age on %DFI revealed that males >45 years of age had the highest %DFI and lowest %HDS compared to all other age groups (p<.001). This study is the largest population study and first of its kind in India that utilises SCSA^® to assess the relevance of %DFI and %HDS to increasing age with potentially important implications for the choice of clinical course based on age and sperm quality of infertile males in India.

Impact of sperm characteristics on time-lapse embryo morphokinetic parameters and clinical outcome of conventional in vitro fertilization

BACKGROUND

Sperm abnormalities may negatively affect embryo development.

OBJECTIVES

To determine the influence of sperm abnormalities (morphology, motility, DNA fragmentation) on embryo morphokinetic variables and clinical outcome of conventional IVF.

MATERIALS AND METHODS

Participants were 86 couples undergoing in vitro fertilization (IVF). Sperm morphology was evaluated according to the strict criteria proposed by Kruger/Tygerberg. CASA system was applied for sperm motility assessment. Sperm DNA fragmentation was assessed by the chromatin structure assay (SCSA). Morphokinetic parameters were determined in 223 embryos obtained from conventional IVF only and cultured in a single-step medium using time-lapse imaging technology.

RESULTS

Time-lapse variables from the initial embryo development, such as time of pronuclei fading (tPNf) and time for two cells (t2), were those more strongly related with abnormalities of sperm motility, morphology, and DNA fragmentation. Sperm morphological abnormalities rather than sperm motility were more closely associated with embryo morphokinetics. Sperm head defects were mainly correlated with the last stages of embryonic development (t9 to tHB), sperm midpiece defects with intermediate cleaving embryos (t5-t9), and sperm tail defects with the initial stages of embryonic development (tPNa-t4). Excess residual cytoplasm was positively correlated with all embryo morphokinetic parameters except t2 and tM. Absence of acrosomes, pinheads, coiled tails, and multiple sperm morphological defects correlated negatively with time-lapse embryo morphokinetic variables.

DISCUSSION

A large number of sperm-related variables, including frequency of specific morphological defects, morphological indexes, DNA fragmentation and motility, and time-lapse embryo variables, such as time intervals based mainly of 15 time points were recorded.

CONCLUSION

There were strong associations between specific sperm defects of the head, midpiece, and tail with certain stages of embryonic development from observation of pronuclei to the hatched blastocyst. Coiled tail, cumulative head defects, and multiple abnormalities index (MAI) were associated both with embryo morphokinetics and the implantation success.

A Comparison Between Two Assays for Measuring Seminal Oxidative Stress and their Relationship with Sperm DNA Fragmentation and Semen Parameters

Oxidative stress (OS) is a significant cause of DNA fragmentation and is associated with poor embryo development and recurrent miscarriage. The aim of this study was to compare two different methods for assessing seminal OS and their ability to predict sperm DNA fragmentation and abnormal semen parameters. Semen samples were collected from 520 men attending for routine diagnostic testing following informed consent. Oxidative stress was assessed using either a chemiluminescence assay to measure reactive oxygen species (ROS) or an electrochemical assay to measure oxidation reduction potential (sORP). Sperm DNA fragmentation (DFI) and sperm with immature chromatin (HDS) were assessed using sperm chromatin structure assay (SCSA). Semen analysis was performed according to WHO 2010 guidelines. Reactive oxygen species sORP and DFI are negatively correlated with sperm motility (p = 0.0012, 0.0002, <0.0001 respectively) and vitality (p < 0.0001, 0.019, <0.0001 respectively). The correlation was stronger for sORP than ROS. Reactive oxygen species (p < 0.0001), sORP (p < 0.0001), DFI (p < 0.0089) and HDS (p < 0.0001) were significantly elevated in samples with abnormal semen parameters, compared to those with normal parameters. Samples with polymorphonuclear leukocytes (PMN) have excessive ROS levels compared to those without (p < 0.0001), but sORP and DFI in this group are not significantly increased. DNA fragmentation was significantly elevated in samples with OS measured by ROS (p = 0.0052) or sORP (p = 0.004). The results demonstrate the multi-dimensional nature of oxidative stress and that neither assay can be used alone in the diagnosis of OS, especially in cases of leukocytospermia.

Cap-Score™ prospectively predicts probability of pregnancy

Semen analysis (SA) poorly predicts male fertility, because it does not assess sperm fertilizing ability. The percentage of capacitated sperm determined by G_M1 localization (“Cap‐Score™”), differs between cohorts of fertile and potentially infertile men, and retrospectively, between men conceiving or failing to conceive by intrauterine insemination (IUI). Here, we prospectively tested whether Cap‐Score can predict male fertility with the outcome being clinical pregnancy within ≤3 IUI cycles. Cap‐Score and SA were performed (n = 208) with outcomes initially available for 91 men. Men were predicted to have either low (n = 47) or high (n = 44) chance of generating pregnancy using previously‐defined Cap‐Score reference ranges. Absolute and cumulative pregnancy rates were reduced in men predicted to have low pregnancy rates versus high ([absolute: 10.6% vs. 29.5%; p = 0.04]; [cumulative: 4.3% vs. 18.2%, 9.9% vs. 29.1%, and 14.0% vs. 32.8% for cycles 1–3; n = 91, 64, and 41; p = 0.02]). Only Cap‐Score, not male/female age or SA results, differed significantly between outcome groups. Logistic regression evaluated Cap‐Score and SA results relative to the probability of generating pregnancy (PGP) for men who were successful in, or completed, three IUI cycles (n = 57). Cap‐Score was significantly related to PGP (p = 0.01). The model fit was then tested with 67 additional patients (n = 124; five clinics); the equation changed minimally, but fit improved (p < 0.001; margin of error: 4%). The Akaike Information Criterion found the best model used Cap‐Score as the only predictor. These data show that Cap‐Score provides a practical, predictive assessment of male fertility, with applications in assisted reproduction and treatment of male infertility.

Analysis on the association between sperm DNA fragmentation index and conventional semen parameters, blood microelements and seminal plasma ROS in male patients with infertility

We conducted this study to analyze the sperm DNA fragmentation index, conventional semen parameters, blood microelements and seminal plasma reactive oxygen species (ROS) in patients with male infertility to determine the association between each of the above male physiological parameters and DNA fragmentation index and infertility. Eighty cases of infertile males and 20 cases of normal males with children were divided into the infertility and control groups, respectively. Sperm DNA fragmentation index, conventional semen parameters, serum microelement content and seminal plasma ROS levels were detected, and the existing correlation between sperm DNA fragmentation index and the various physiological parameters were studied. The sperm DNA fragmentation index had no correlation with conventional sperm parameters. Our results demonstrated that zinc, lead and magnesium ions in the serum microelements were correlated with sperm DNA fragmentation (p<0.05). Upon an increase in zinc and lead serum concentration, there was a subsequent increase in sperm DNA fragmentation (p=0.008). Furthermore, when magnesium ion increased, it also caused an increase in sperm DNA fragmentation (p<0.05). The seminal plasma ROS of infertile males was higher than that of males with children (p<0.05). Our results suggest that sperm DNA fragmentation index is closely associated with the infertility rate and microelements of serum and seminal plasma ROS can impact the formation of sperm DNA fragmentation. Therefore, the sperm DNA fragmentation index can serve as an important parameter to assess male infertility.

Investigation on the origin of sperm morphological defects: oxidative attacks, chromatin immaturity, and DNA fragmentation

DNA fragmentation can be deleterious on spermatozoon morphology but the pathogenesis of teratozoospermia associated with DNA breaks is not fully understood, even if oxidative attacks and defects in chromatin maturation are hypothesized. Therefore, this study is one of the first to clarify on the underlying hypothesizes behind such observations. The objectives of our study were to assess the role of oxidative attacks in DNA damage pathogenesis in ejaculated spermatozoa from patients with isolated teratozoospermia. We aimed to assess the correlation of DNA breaks with morphologically abnormal spermatozoa, as well as ROS level and impairment chromatin condensation. A total of 90 patients were divided into two groups, men with isolated teratozoospermia (n = 60) and men with normal semen parameters (n = 30) as controls. DNA fragmentation was evaluated by TUNEL assay; chromatin immaturity was studied using acridine orange and toluidine blue staining. We evaluated the ability of spermatozoa to produce reactive oxygen species with nitro blue tetrazolium staining. Patient with teratozoospermia when compared to fertile men showed significantly higher rates of semen ROS production, sperm hypocondensated chromatin, denaturated DNA, and fragmented DNA. All these parameters were positively correlated with abnormal sperm morphology. The studied DNA integrity markers were also correlated with ROS production. Fragmented DNA is the main pathway leading to morphology defects in the sperm. In fact, impaired chromatin compaction may induce DNA breaks and free radicals, which can break the DNA backbone indirectly, by reducing protamination and disulphide bond formation, as oxidative attack appears to be the major cause of poor semen morphology.

Revisiting The Relationship between The Ejaculatory Abstinence Period and Semen Characteristics

Variation in the ejaculatory abstinence period suggested by different guidance bodies have resulted in a growing concern among researchers and clinicians over what the precise period of ejaculatory abstinence ought to be for an optimal semen sample. Several studies have thus been undertaken to examine the association between the length of sexual abstinence and semen characteristics. Not all studies, however, have arrived at the same conclusions. This study aims to review all existing literature published during the past few decades pertaining to the influence of ejaculatory abstinence on semen quality. For the purpose of this systematic review, all data related to sexual abstinence duration and seminal parameters were re-analysed to homogenize the current data. Thorough PubMed, MEDLINE and Google Scholar, a literature search was conducted using the keywords "sexual abstinence", "ejaculatory abstinence", "semen", "spermatozoa", "semen analysis", "sperm parameters", "motility", "reactive oxygen species (ROS)" and "DNA fragmentation". After carefully reviewing all the literature, 30 relevant papers, both written in English and published between January 1979 and December 2016, were included in this review. The weight of the evidence suggests that the decline in semen volume and sperm concentration with shorter abstinence periods is accompanied by a substantial improvement in sperm motility characteristics, especially progressive motility and velocity. Nevertheless, available data are insufficient to support definitive conclusions regarding the influence of the ejaculatory abstinence period on advanced semen parameters (ROS, DNA fragmentation and seminal plasma antioxidant capacity) and pregnancy rates. In conclusion, taking all data into account, shortening of the abstinence period may be beneficial to sperm quality. Furthermore, we recommend that the current guidelines regarding the prescribed abstinence period should be revisited.

Sleep duration is associated with sperm chromatin integrity among young men in Chongqing, China

This study explores whether sleep duration is associated with sperm chromatin integrity. To do so, we conducted a three-phase panel study of 796 male volunteers from colleges in Chongqing (China) from 2013 to 2015. Sleep duration was measured using a modified Munich Chronotype Questionnaire. Sperm DNA integrity was examined via Sperm Chromatin Structure Assay and Comet assay. Setting 7-7.5 h day^-1 of sleep duration as a reference, either longer or shorter sleep duration was associated negatively with high DNA stainability (HDS) (P = 0.009), which reflected the immaturity of sperm chromatin. The volunteers with > 9.0 h day^-1 sleep and those with ≤ 6.5 h day^-1 sleep had 40.7 and 30.3% lower HDS than did volunteers with 7-7.5 h day^-1 sleep. No association was found between sleep duration and DNA fragmentation index or Comet assay parameters. This study suggests that sleep duration is associated with sperm chromatin integrity. Further studies are required to validate these findings and investigate the mechanism underlying this association.

Does sperm quality and DNA integrity differ in cryopreserved semen samples from young, adult, and aged Nellore bulls?

Background

In humans, it is now well documented that rising paternal age is correlated with decreased sperm DNA integrity and embryonic developmental failures. On the other side of the coin, it is also reported that very young fathers such as teenagers carry an increased risk of adverse birth outcomes. These observations suggest that, at least in humans, there is an age window for optimal sperm DNA integrity. In bovine, little is known about sperm DNA quality in young bulls and how it evolves with age. This study aimed to fill in this gap as it may be of importance for the bovine industry to know when exactly a bull is an optimal performer for reproductive programs.

Methods

Forty Nellore bulls were divided into three age groups: 1.8 to 2 years – young bulls; 3.5 to 7 years – adult bulls; and 8 to 14.3 years – aged bulls. Three ejaculates were collected from each bull, cryopreserved and evaluated for various parameters including: computer-assisted sperm analysis (CASA), plasma membrane and acrosome integrity, mitochondrial potential, sperm nuclear protamination, DNA oxidative damage, and Sperm Chromatin Structure Assay (SCSA).

Results

We report here that young bulls presented superior values for motility, plasma and acrosomal membrane integrity, and high mitochondrial potential. However, they also presented higher values for sperm morphological abnormalities compared to adult and aged animal groups (p < 0.05). In addition, young bulls exhibited more defective protamination than older animals did. The oldest bulls showed more nuclear oxidative damage than the younger groups of bulls while both the young and aged groups were found more susceptible to DNA denaturation as revealed with the SCSA test (p < 0.05).

Conclusion

These results indicate that young bulls spermatozoa best survived the freezing procedure, followed by adult and aged bulls. However, young and aged bulls were found to be more susceptible to DNA damage, respectively caused by protamine deficiency and oxidation. Therefore, although young bulls have correct semen parameters according to classical evaluation, our results indicate that they may show some structural nuclear immaturity.

Grape juice concentrate alleviates epididymis and sperm damage in cadmium-intoxicated rats

The possibility of long-term grape juice concentrate (GJC) consumption conferring a protective effect against cadmium (Cd)-induced damage to the epididymis, completely preserving sperm profile, was evaluated here for the first time in the scientific literature. Male Wistar rats (n = 6/per group) received an intraperitoneal Cd injection (1.2 mg/Kg) at age 80 days and GJC (2 g/Kg) by gavage from 50 days until 136 days old. Groups receiving either Cd or GJC were added. An intraperitoneal injection of saline (0.9%) and water by gavage was administered in the absence of treatment with Cd or GJC. Animals were anaesthetized and exsanguinated at 136 days; the vas deferens, left testis and epididymis were removed; and perfusion continued with fixative. The right epididymis was collected for morphological analysis. Cd had a devastating effect demonstrated by reduced sperm count in testes and epididymis, sperm production and normal sperm count, besides increased epididymis sperm transit time and completely disorganized morphology. These alterations were attributed to higher Cd levels in the testes and a lipid peroxidation (LP) process. Consumption of GJC plus Cd intoxication was effective, reducing metal accumulation and LP. Consequently, we could identify a preserved sperm profile, with improvement in testis and epididymis sperm count, normal sperm structure and sperm transit time. Moreover, GJC extends its protective effect to the epididymis, allowing complete re-establishment of its morphology, ensuring successful sperm maturation process. In conclusion, our study indicates long-term GJC as a promising therapy against reproductive chemical intoxication injury damage, preserving sperm prior to ejaculation.

Localization patterns of the ganglioside GM1 in human sperm are indicative of male fertility and independent of traditional semen measures

Semen analysis lacks a functional component and best identifies extreme cases of infertility. The ganglioside G_M1 is known to have functional roles during capacitation and acrosome exocytosis. Here, we assessed whether G_M1 localization patterns (Cap‐Score™) correspond with male fertility in different settings: Study 1 involved couples pursuing assisted reproduction in a tertiary care fertility clinic, while Study 2 involved men with known fertility versus those questioning their fertility at a local urology center. In Study 1, we examined various thresholds versus clinical history for 42 patients; 13 had Cap‐Scores ≥39.5%, with 12 of these (92.3%) achieving clinical pregnancy by natural conception or ≤3 intrauterine insemination cycles. Of the 29 patients scoring <39.5%, only six (20.7%) attained clinical pregnancy by natural conception or ≤3 intrauterine insemination cycles. In Study 2, Cap‐Scores were obtained from 76 fertile men (Cohort 1, pregnant partner or recent father) and compared to 122 men seeking fertility assessment (Cohort 2). Cap‐Score values were normally distributed in Cohort 1, with 13.2% having Cap‐Scores more than one standard deviation below the mean (35.3 ± 7.7%). Significantly, more men in Cohort 2 had Cap‐Scores greater than one standard deviation below the normal mean (33.6%; p = 0.001). Minimal/no relationship was found between Cap‐Score and sperm concentration, morphology, or motility. Together, these data demonstrate that Cap‐Score provides novel, clinically relevant insights into sperm function and male fertility that complement traditional semen analysis. Furthermore, the data provide normal reference ranges for fertile men that can help clinicians counsel couples toward the most appropriate fertility treatment.

Improving ICSI: A review from the spermatozoon perspective

Intracytoplasmic sperm injection (ICSI) is the most frequently applied method for fertilization making the process of identifying the perfect spermatozoon fundamental. Herein we offer a critical and thorough presentation on the techniques reported regarding (i) handling and preparing semen samples, (ii) identifying and 'fishing' spermatozoa, and (iii) improving key factors, such as motility for a successful ICSI practice. These approaches are suggested to make the process easier and more effective especially in atypical and challenging circumstances. Furthermore, we present an epigrammatic opinion-where appropriate-based upon our collective experience. Techniques such as intracytoplasmic morphologically selected sperm injection, hyaluronic binding, polarized light microscopy, and annexin V agent identification for comparing sperm cells and their chromatin integrity are analyzed. Moreover, for the demanding cases of total sperm immotility the use of the hypoosmotic swelling test, methylxanthines, as well as the option of laser assisted immotile sperm selection are discussed. Finally, we refer to the employment of myoinositol as a way to bioreactively improve ICSI outcome for oligoasthenoteratozoospermic men. The diversity and the constant development of novel promising techniques to improve ICSI from the spermatozoon perspective, is certainly worth pursuing. The majority of the techniques discussed are still a long way from being established in routine practices of the standard IVF laboratory. In most cases an experienced embryologist could yield the same results. Although some of the techniques show great benefits, there is a need for large scale multicenter randomized control studies to be conducted in order to specify their importance before suggesting horizontal application. Taking into consideration the a priori invasive nature of ICSI, when clinical application becomes a possibility we need to proceed with caution and ensure that in the pursuit for innovation we are not sacrificing safety and the balance of the physiological and biological pathways of the spermatozoon's dynamic.

ABBREVIATIONS

ICSI: intracytoplasmic sperm injection; IVF: in vitro fertilization; PGD: reimplantation genetic diagnosis; IVM: in vitro maturation; HCV/HIV: hepatitis C virus/human immunodeficiency virus; IMSI: intracytoplasmic morphologically selected sperm injection; DGC: density gradient centrifugations; S-U: swim-up; ART: assisted reproduction technology; IUI: intrauterine insemination; PVP: polyvinylpyrrolidone; HA: hyaluronic acid; MSOME: motile sperm organelle morphology examination; ZP: zona pellucida; MACS: magnetic activation cell sorting; HOST: hypo-osmotic swelling test; TESE: testicular sperm extraction; MMP: mitochondrial membrane potential; OAT: oligoasthenoteratozoospermic.

Turning the corner in fertility: high DNA integrity of boundary-following sperm

We present a passive microfluidic sperm selection strategy that collects motile sperm based on their preference to follow boundaries and turn corners. Clinical assessment of selected human sperm from the device revealed a strong correlation between high DNA integrity and the tendency for sperm to follow boundaries. Human sperm with preference to follow boundaries on the left- or right-hand sides have higher (>51%) DNA integrity than straight swimmers and significantly higher (>67%) DNA integrity than sperm in raw semen. Boundary following behaviour offers a strategy to selecting sperm with the highest DNA integrity to improve the success rate of assisted reproduction.

Fourier transform infrared spectroscopic analysis of sperm chromatin structure and DNA stability

Sperm chromatin structure and condensation determine accessibility for damage, and hence success of fertilization and development. The aim of this study was to reveal characteristic spectral features coinciding with abnormal sperm chromatin packing (i.e., DNA-protein interactions) and decreased fertility, using Fourier transform infrared spectroscopy. Chromatin structure in spermatozoa obtained from different stallions was investigated. Furthermore, spermatozoa were exposed to oxidative stress, or treated with thiol-oxidizing and disulfide-reducing agents, to alter chromatin structure and packing. Spectroscopic studies were corroborated with flow cytometric analyses using the DNA-intercalating fluorescent dye acridine orange. Decreased fertility of individuals correlated with increased abnormal sperm morphology and decreased stability toward induced DNA damage. Treatment with the disulfide reducing agent dithiothreitol resulted in increased sperm chromatin decondensation and DNA accessibility, similar as found for less mature epididymal spermatozoa. In situ infrared spectroscopic analysis revealed that characteristic bands arising from the DNA backbone (ν1230, ν1086, ν1051 cm(-1) ) changed in response to induced oxidative damage, water removal, and decondensation. This coincided with changes in the amide-I region (intensity at ν1620 vs. ν1640 cm(-1) ) denoting concomitant changes in protein secondary structure. Reduction in protein disulfide bonds resulted in a decreased value of the asymmetric to symmetric phosphate band intensity (ν1230/ν1086 cm(-1) ), suggesting that this band ratio is sensitive for the degree of chromatin condensation. Moreover, when analyzing spermatozoa from different individuals, it was found that the asymmetric/symmetric phosphate band ratio negatively correlated with the percentage of morphologically abnormal spermatozoa.

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.

Hyaluronic Acid Binding Assay Is Highly Sensitive to Select Human Spermatozoa with Good Progressive Motility, Morphology, and Nuclear Maturity

OBJECTIVE

This study was performed to evaluate the correlation of hyaluronic acid binding assay (HBA) with conventional semen parameters, lipid peroxidation (LPO), intracellular reactive oxygen species (ROS), DNA fragmentation (DF), DNA maturity and mitochondrial membrane potential (MMP) level in human spermatozoa.

METHODS

The semen samples were obtained from 98 patients. The seminal plasma was separated for the study of LPO, and the pellet was employed for evaluation of intracellular ROS, DF, nuclear maturity (sperm chromatin structure assay) and MMP through flowcytometry.

RESULTS

The correlation and strength of HBA with respect to the studied parameters were estimated by the Pearson coefficient and multiple liner regression tests. While HBA indicated a positive correlation with progressive motility (β-coefficients = 0.449, p < 0.05) and normal morphology (β-coefficients = 2.722, p < 0.01), it had only negative relationship with DNA integrity (high DNA stain ability; β-coefficients = -0.517, p < 0.05). HBA also did not show any important correlation with other conventional and intracellular sperm parameters.

CONCLUSIONS

The HBA is sensitive to morphological integrity, high progressive motility and nuclear maturation. Nonetheless, HBA is not a reliable test for prediction of sperm intracellular ROS, DF and MMP risks and healthy spermatozoa selection.

Holographic imaging of unlabelled sperm cells for semen analysis: a review

Male reproductive health in both humans and animals is an important research field in biological study. In order to characterize the morphology, the motility and the concentration of the sperm cells, which are the most important parameters to feature them, digital holography demonstrated to be an attractive technique. Indeed, it is a label-free, non-invasive and high-resolution method that enables the characterization of live specimen. The review is intended both for summarizing the state-of-art on the semen analysis and recent achievement obtained by means of digital holography and for exploring new possible applications of digital holography in this field. Quantitative phase maps of living swimming spermatozoa.

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.

Sperm nuclear DNA fragmentation and its association with semen quality in Greek men

Due to the limitations of conventional semen analysis in predicting a man's fertility potential, sperm DNA fragmentation was recently introduced as a novel marker of sperm quality. This prospective study was undertaken to investigate the associations between conventional seminal parameters and DNA fragmentation in Greek men. A total of 669 subject data were evaluated in two groups, normozoospermic (n = 184) and non-normozoospermic (n = 485), according to the WHO 2010 (WHO Laboratory Manual for the Examination and Processing of Human Semen, 5th edn. World Health Organization), reference limits. For all the subjects, semen volume, sperm concentration, total count, rapid and total progressive motility and morphology were recorded following the WHO 2010 methods and DNA fragmentation was assessed by the sperm chromatin dispersion assay. An inverse correlation was established between DNA fragmentation and all conventional seminal parameters except semen volume in men with seminal profiles below the reference limits, with statistical significance for rapid and total progressive motility. Normozoospermic men exhibited lower levels of DNA fragmentation than their non-normozoospermic counterparts, even though the values were not always below 30%. DNA fragmentation testing and traditional semen analysis should therefore be considered as complementary diagnostic tools in a comprehensive evaluation of male infertility.

Assessment of chromatin maturity in human spermatozoa: useful aniline blue assay for routine diagnosis of male infertility

During spermatogenesis, sperm chromatin undergoes structural changes and results in a high condensation. This nuclear compaction would be useful as a predictor of sperm fertilization capacity and pregnancy outcome. We purpose to evaluate firstly the relationship among chromatin maturity assessed by aniline blue staining (AB) and the semen parameters in infertile men. Secondly, we analyzed whether the sperm gradient density centrifugation is effective to select mature spermatozoa. Fifty-one ejaculates were investigated by semen analysis and stained for chromatin condensation with AB to distinguish between unstained mature sperm and stained immature sperm. AB was applied also on 12 ejaculates which proceeded by density gradient centrifugation to compare the rates of immature sperm before and after selection. Neat semen were divided into two groups: G1 (n = 31): immature sperm <20% and G2 (n = 20): immature sperm ≥20%. No significant differences were detected in sperm concentration, motility, and normal morphology between G1 and G2. However, the rates of some morphology abnormalities were higher in G2: head abnormalities (P = 0.01) and microcephalic sperm (P = 0.02). We founded significant correlation between sperm immaturity and acrosome abnormalities (r = 0.292; P = 0.03). Sperm selection has significantly reduced the rates of immature sperm. A better understanding of chromatin structure and its impact on the sperm potential is needed to explore male infertility.

Relationship between reactive oxygen species production in human semen and sperm DNA damage assessed by Sperm Chromatin Structure Assay

AIM

The aim of this prospective study was to find possible relationship between ROS production measured by chemiluminescence and flow cytometry in human semen and sperm DNA damage estimated by Sperm Chromatin Structure Assay.

METHODS

Study included 39 men from infertile couples and 23 fertile volunteers who served as a control group. Aliquot of neat semen was used for ROS detection by chemiluminescence. Aliquot of sperm suspension in phosphate buffered saline was used for the detection of ROS by flow cytometry. Another aliquot of sperm suspension was used for SCSA to measure DNA fragmentation index and High DNA stainability.

RESULTS

DNA fragmentation index correlated negatively with sperm morphology and motility. High DNA stainability correlated positively with ROS production and negatively with sperm morphology and concentration. Although there were similar trends of rising DNA fragmentation index and ROS production among the three groups of men, the relationship did not reach statistical significance.

CONCLUSIONS

Higher values of DNA fragmentation index and high DNA stainability may also reflect developmental and/or environmental problems and not only oxidative stress.

Grape juice concentrate protects reproductive parameters of male rats against cadmium-induced damage: a chronic assay

The aim of the present study was to investigate the effects of long-term grape juice concentrate (GJC) consumption, in two dosages, on the reproductive parameters of cadmium-exposed male rats. The effects of the concentrate on body mass gain, plasma testosterone levels, reproductive organ weights, daily sperm production, sperm morphology, testis histopathological and histomorphometrical parameters, and testicular antioxidant markers were investigated. Wistar rats (n 54) were distributed into six groups: CdCl2; cadmium and grape juice I (1·18 g/kg per d); cadmium and grape juice II (2·36 g/kg per d); grape juice I (1·18 g/kg per d); grape juice II (2·36 g/kg per d); control. A single dose of CdCl2 (1·2 mg/kg body weight (BW)) was injected intraperitoneally and the grape juice was administered orally for 56 d. The results indicated that cadmium changed all reproductive and antioxidant parameters. At dosage I (1·18 g/kg BW), GJC consumption did not show the effects against cadmium-induced damages. In contrast, at dosage II (2·36 g/kg BW), the GJC improved the gonadosomatic index (P= 0·003), serum testosterone levels (P= 0·001), the relative weight of epididymis (P= 0·013) and ventral prostate (P= 0·052), the percentage of normal sperm (P= 0·001), and histopathological and histomorphometrical parameters. In addition, at this dosage, normalisation of the enzymatic activity of superoxide dismutase (P= 0·001) and of testicular levels of glutathione (P= 0·03) were observed. The parameters of the non-exposed rats did not depict significant alterations. In conclusion, the product was able to act as a protector of reproductive function against cadmium-induced damage. Such a property was expressed in a dose-dependent manner as the more effective dose was dosage II. The GJC acted possibly by antioxidant mechanisms.

Sperm DNA damage: how relevant is it clinically?

PURPOSE OF REVIEW

The true impact of the current sperm DNA fragmentation testing needs further scrutiny to assess whether clinically meaningful information is conveyed.

RECENT FINDINGS

Various studies have suggested different or no threshold values with assorted tests for the percentage of DNA fragmentation in the ejaculated sperm above which natural conception, fertilization or embryo development and/or clinical pregnancy rates are compromised. Current DNA fragmentation assessment methods provide very little specific information on the nature and severity of the DNA damage detected. Although sperm DNA fragmentation is associated with lower pregnancy rates through natural conception or intrauterine insemination, it does not seem to affect intracytoplasmic sperm injection outcome. Although animal studies demonstrated adverse reproductive effects of sperm DNA fragmentation, any conclusive evidence in humans is yet to be demonstrated. It is not clear whether interventions aimed at enrichment of sperm with decreased DNA fragmentation are effective in preventing the potential adverse effects of sperm DNA fragmentation in humans. Major concern about the use of sperm DNA integrity tests as prognostic parameters is that the direct evaluation of DNA fragmentation in individual sperm fertilizing the oocyte is not possible.

SUMMARY

The lack of consensus in defining a clinically relevant standard DNA fragmentation test with a meaningful cut-off level brings challenges in implementing the routine use of sperm DNA integrity assessment in daily practice.

Predictive value of DNA integrity analysis in idiopathic recurrent pregnancy loss following spontaneous conception

PURPOSE

Standard semen parameters are poor predictors of fertility potential. To date, apart from, paternal karyotyping sperm factors are not evaluated in recurrent pregnancy loss (RPL), only recent studies have emphasized the role of sperm factors in early embryonic development as sperm transcribes genes critical for early embryonic development. Sperm DNA integrity is useful diagnostic and prognostic marker and has clinical implications in idiopathic recurrent pregnancy loss (iRPL) following spontaneous conception. The aim of this study was to assess DNA integrity in cases experiencing iRPL following spontaneous conception.

METHODS

Semen samples from 45 patients and 20 controls were analyzed as per WHO 1999 guidelines and sperm chromatin structure assay (SCSA) was used to measure DNA fragmentation index (DFI).

RESULTS

By applying receiver operating curve (ROC) analysis, sperm DFI of approximately 26 % was found in male partner of couples experiencing iRPL.

CONCLUSIONS

Our data indicate that sperm from men with a history of iRPL have a higher percentage of DNA damage as compared to control group, and this can explain pregnancy loss in these patients. Men with higher DFI are infertile whereas men with lower DFI (26 %) are able to conceive but experience recurrent pregnancy loss. Thus it is important to evaluate sperm DFI in couples experiencing iRPL to understand exact aetiology of RPL and determine prognosis and management.

Effects of cryostorage on human sperm chromatin integrity

The integrity of sperm chromatin structure has proven to be of great importance for human fertility. In this study, we investigated whether sperm cryopreservation has an effect on nuclear DNA tertiary structure, (i.e. condensation), measured by aniline blue staining, in 103 male patients who required consultation for hypo-fertility. Sperm DNA damage was significantly higher in patients showing oligospermia and severe morphological abnormalities than in native sperm populations. Furthermore we observed that chromatin decondensation was related to the cryostorage technique and to the duration of storage. This increase in decondensation was highly significant (P < 0.01) immediately after cryopreservation and from 90 days of cryostorage onwards. The possible mechanisms involved in sperm chromatin cryoinjury and the need to incorporate new methods for testing sperm nuclear structure alteration into the routine spermiogram are discussed.

Improvement in chromatin maturity of human spermatozoa selected through density gradient centrifugation

A two-step gradient density centrifugation system has been set up to isolate two contrasting sperm populations of normozoospermic and oligoasthenoteratozoospermic (OAT) men. High- and low-density fractions were characterized by total and free thiol fluorescence as determined by monobromobimane-flow cytometry and by protamine/DNA ratios after protamine extraction and polyacrylamide acid-urea gel electrophoresis. Further chromatin characterization was performed through immunofluorescence (IF) with specific antibodies to nucleosomes, histone subtypes (H3.1/H3.2 and TH2B), histone modifications (KM-2 and H4K8ac) and precursor protamine 2. The native sperm samples from normozoospermic and OAT patients showed a biphasic distribution of total thiol levels, which changed in the sperm fractions obtained using the density isolation protocol presented here. Moreover, significant differences were detected in the protamine content in the different fractions of OAT and fertile donor samples. In addition, in the high-density fractions from OAT and normozoospermics, higher IF levels for H4K8ac and TH2B were seen. These results would be consistent with the intended beneficial effect on chromatin maturity of the density selection techniques currently being used in assisted fertilization procedures. However, most nucleosome and related proteins/modifications differ between OAT and normozoospermic men, even after gradient centrifugation, providing evidence for incomplete nuclear maturity in OAT patients.

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.

Digital holographic microscopy in human sperm imaging

PURPOSE

The aim of this study was to use digital holographic microscopy (DHM) in human sperm imaging and compare quantitative phase contrast of sperm heads in normozoospermia (NZ) and oligoasthenozoospermia (OAT).

METHODS

DHM spermatozoa imaging and repeated quantitative phase shift evaluation were used. Five NZ and 5 OAT samples were examined. Semen samples were examined by semen analysis and processed for DHM. Main outcome measures were maximum phase shift value of the sperm heads. Differences of the phase shift and in NZ and OAT samples were statistically tested.

RESULTS

In NZ samples median phase shifts were in the range 2.72-3.21 rad and 2.00-2.15 in OAT samples. Differences among individual samples were statistically significant (p < 0.001) in both groups. Median phase shift according to sperm count was 2.90 rad in NZ samples and 2.00 rad in OAT samples. This difference was statistically significant (p < 0.001).

CONCLUSION

Quantitative evaluation of the phase shift by DHM could provide new information on the exact structure and composition of the sperm head. At present, this technique is not established for clinical utility.

Reproductive toxic potential of panmasala in male Swiss albino mice

Some ingredients of panmasala have the ability to penetrate the blood-testis barrier but the reproductive toxic potential of panmasala has not been studied. This study is aimed to assess the possible damage caused by panmasala to male reproductive system in mice. Swiss albino male mice were randomly divided into 7 groups receiving either standard control diet or panmasala-containing diet. Three doses (0.5%, 1.5% and 3%) of panmasala plain (PMP) as well as panmasala with tobacco (PMT)—gutkha were given for a period of 6 months. Assessment of organ weight, sperm count and morphology, spermatid count, sperm production, testicular 17β-hydroxysteroid dehydrogenase (17β-HSD) activity and histology were conducted. A nonsignificant decrease in absolute and relative weight of testis and epididymis was observed. Spermatid count, sperm count and production were significantly decreased and 17β-HSD activity was found considerably declined at 3% of both PMP- and PMT-treated groups as compared to control. The histological observations revealed panmasala induced testicular damage. Abnormal morphology of sperm head shape was significantly elevated in higher doses of both types of panmasala-treated groups than control. The results suggests that panmasala has reproductive toxic potential and more alteration is seen with gutkha as compared to panmasala plain, indicating that similar effects might also be possible in humans.

Sperm chromatin condensation in infertile men with varicocele before and after surgical repair

OBJECTIVE

To assess sperm chromatin integrity in infertile men with varicocele before and after surgical repair.

DESIGN

Prospective.

SETTING

Academic setting.

PATIENT(S)

Seventy-two infertile men with varicocele compared with 20 healthy fertile men.

INTERVENTION(S)

History taking, genital examination, semen analysis, sperm chromatin condensation assessment by aniline blue stain before and 3 months after varicocelectomy.

MAIN OUTCOME MEASURE(S)

Stained sperm heads (abnormal chromatin condensation) before and 3 months after varicocelectomy.

RESULT(S)

The mean percentage of aniline blue-stained sperm heads was significantly higher in infertile men with varicocele compared with fertile controls. The mean percentage of stained sperm heads was significantly decreased in infertile men with varicocele 3 months after surgery compared with the preoperative data. There was a significant negative correlation between percentage of stained sperm heads and normal morphology where nonsignificant correlation was elicited regarding sperm count and sperm motility.

CONCLUSION(S)

There is a significant increase of abnormal sperm chromatin condensation in infertile men with varicocele that is markedly improved after varicocelectomy.