Cytochemical evaluation of sperm chromatin and DNA integrity in couples with unexplained recurrent spontaneous abortions

Lipid mixtures (from a liposome kit) and melatonin improve post-thawed Angora goat sperm parameters

Semen freezing and storing has been widely used in reproductive biotechnology, being applied to certain males of livestock breeds or animal species with economic value such as the Angora goat. The development of a semen extender with the cryoprotective agents can prevent the deterioration of sperm parameters after thawing. This study aimed to investigate lipid mixtures (from a liposome kit, Lps) and melatonin (Mel) at different doses to prevent the deterioration of sperm parameters and to provide the cryoprotective effects on sperm DNA. The Angora goat ejaculates were collected and pooled. They were divided into seven equal volumes, and each of them was diluted with the extenders of the experimental groups with additives (Lps 321.99 μg/mL, Lps 841.33 μg/mL, Mel 0.25 mM, Mel 1 mM, Lps 321.99 μg/mL + Mel 1 mM, Lps 841.33 μg/mL + Mel 0.25 mM) and no additives (control group). After the freeze-thawing process, motility, viability, acrosome integrity, DNA double-strand breaks, and abnormal DNA integrity were assessed for different extender groups. It was determined that the use of Lps alone at low dose or the combination of Lps and Mel had significant cryoprotective effects on motility, viability, acrosome integrity, and DNA damage in Angora goat sperm. This study will help us to understand the effects of Lps and Mel used alone or in combination at different doses and which doses give the optimum spermatological parameter rates following the freeze-thawing process, and hence it will shed light on further studies.

Male Contributory Factors in Recurrent Pregnancy Loss

With 40% of idiopathic cases, recurrent pregnancy loss (RPL) is a problem of great concern for patients and clinicians. In addition to financial burden, it causes a lot of frustration and anxiety in affected couples. The primary objective of this review was to gain knowledge of recent advances in the field of recurrent pregnancy losses and to understand the role of male contributory factors in idiopathic cases. For a long time, researchers and clinicians were seeking an explanation for idiopathic RPL (iRPL) in females only; however, with recent advances in reproductive biology, the role of spermatozoa in early embryonic development has caught the attention of researchers. Clinically, only routine semen parameters and karyotyping are investigated in iRPL male partners, which seem to be insufficient in the present scenario, and thus, more information at the molecular level is required for a comprehensive understanding of iRPL. In concluding remarks, we suggest targeted multi-omics investigations in a large cohort to improve our understanding of the role of male contributory factors in iRPL.

Advanced sperm tests and impact on clinical male factor management

PURPOSE OF REVIEW

Although semen analysis remains a cornerstone of male fertility evaluation, conventional semen analysis parameters do not assess for DNA integrity or functional capacity of sperm. Sperm DNA fragmentation (SDF) and sperm aneuploidy tests have been utilized as adjunct tools to distinguish fertile and infertile men and predict pregnancy outcomes. This review serves as an update on indications and utility of advanced sperm tests, as well as associated controversies and limitations.

RECENT FINDINGS

Elevated SDF is associated with prolonged time to pregnancy, lower chance of spontaneous pregnancy, and lower live birth rates. Sperm aneuploidy is more frequent in infertile men, in male partners of couples experiencing recurrent pregnancy loss, and recurrent failure of assisted reproductive technology (ART). These tests can, therefore, provide important information to guide management and counseling of infertile couples to optimize reproductive outcomes.

SUMMARY

We evaluated data surrounding SDF and sperm aneuploidy tests, which are utilized both within and beyond the scope of AUA/ASRM guidelines. While the tests at hand require further standardization and randomized controlled studies, the current data suggest strong associations with pregnancy outcomes and can be utilized to counsel and manage infertile males.

Improvement of human sperm properties with platelet-rich plasma as a cryoprotectant supplement

PURPOSE

Platelet-rich plasma (PRP) is a remarkable substance, which involves the growth and proliferation of all cell types. As a source of growth factors, we evaluated whether sperm cryopreservation supplemented with PRP improves the rates of sperm motility, viability, and DNA integrity after vitrification compared with conventional cryo-medium.

MATERIALS AND METHODS

20 normal semen specimens were collected from healthy men. After swim-up preparation, each sample was divided into four aliquots. One, as control, received no treatment, and the other three experimental samples were treated with three different concentrations of PRP as cryoprotectant. Sperm parameters were examined before and after freezing procedure.

RESULTS

PRP had no significant effect on sperm count. Meanwhile, the percentage of sperm progressive motility and viability in the PRP treated samples with 1×10⁵ /µL concentration was significantly higher than control group. Besides, the rate of immotile sperms in these samples was significantly lower than the control. Sperm viability was significantly higher in the PRP samples at 1×10⁵/µL concentration. In the case of DNA integrity, CMA3 staining showed that the lower PRP concentration was correlated with the higher rate of abnormal spermatozoa. SCD showed that the rate of abnormal sperms in the PRP samples with 1×10⁵ /µL concentration was significantly lower than control group.

CONCLUSIONS

This study showed a protective effect of PRP on human sperm quality at an optimized concentration after vitrification. Besides, the effects of PRP supplementation of sperms on successful fertility following sperm preservation will be of interest.

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

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

Human Sperm Morphology as a Marker of Its Nuclear Quality and Epigenetic Pattern

Background: Human sperm chromatin condensation is a sum of epigenetic events that allows for the near-complete replacement of histones with protamines. Under high-magnification microscopy, nuclear vacuoles have been described as thumbprints with poor chromatin condensation. The objective of this study is to examine whether vacuolated spermatozoa carry specific epigenetic marks, which may influence embryo development. Methods: The presence and three-dimensional distribution of ten epigenetic marks (protamine-P2, histone-H3, H3K4me1/me2/me3, H3K9me1/me2/me3, H3K27me3, H4k20me2) were evaluated and compared in morphometrically normal spermatozoa according to the presence or absence of a large vacuole occupying more than 15% of the head surface (n = 4193). Results: Vacuolated spermatozoa were significantly more frequently labelled with H3 and H3K4me3 than normal spermatozoa (88.1% ± 2.7 and 78.5% ± 5.2 vs. 74.8% ± 4.8 and 49.1% ± 7.4, respectively; p = 0.009 and p < 0.001) and significantly less marked by P2 and H3K27me3 (50.2% ± 6.2 and 63.9% ± 6.3 vs. 82.1% ± 4.4 and 73.6% ± 5.1, respectively; p < 0.001 and p = 0.028). In three dimensions, vacuoles are nuclear concavities filled with DNA carrying the H3K4me3 marker. Conclusion: High-magnification microscopy is a simple tool to estimate in real time the sperm epigenetic profile. The selection of normal spermatozoa without vacuoles and the deselection of spermatozoa with vacuoles appear to be epigenetically favorable to embryo development and safe offspring.

Aerobic training mitigates the negative impact of diabetes on fertility

Diabetes negatively affects the reproductive system. This present study investigated the effects of aerobic training on protamine 1 and 2 mRNA expression, sex hormones, antioxidant defence and sperm quality in diabetic rats. Thirty-six male Wistar rats were randomly allocated into three groups including diabetic training (DT) group, diabetic (D) group and control (C) group. Rats in DT were exercised 5 times per week for 8 weeks. Blood samples were collected for evaluation of sex hormones 48 h after the last training session. Also, the testes were removed and subjected to histological evaluation and semen analysis. Testicular mRNA expressions of protamines were determined by RT-qPCR. Protamines 1 and 2, and the ratio of protamine 1 to protamine 2 were significantly lower in DT and D groups compared with C group (p < 0.01). LH and testosterone levels were significantly lower in D group compared with DT and C group (p < 0.01). Malondialdehyde was significantly lower in DT and C groups compared with D group (p < 0.001). Sperm parameters were significantly lower in D group compared with C group (p < 0.01). Our findings suggest that aerobic training may mitigate the negative impact of diabetes on sex hormones, oxidative stress, protamine content and sperm parameters in male rats.

Effect of bacterial infection on sperm quality and DNA fragmentation in subfertile men with Leukocytospermia

Background

Although bacterial infections have been recognized as a possible cause of male infertility, the effect of bacterial infections on sperm quality and sperm DNA fragmentation remains controversial. The current study aimed to investigate the prevalence rate of bacterial infection in subfertile men and its effect on semen quality. Seminal fluid was collected from 172 male members of infertile couples attending the andrology infertility center and a group of 35 fertile subjects as a control. Sperm parameters and DNA fragmentation were evaluated based on the type of bacteria in all ejaculates.

Results

From the 172 patients investigated for infertility, 60 (34.88%) patients had a positive culture for pathogenic bacteria of different species. Leukocytospermia was significantly higher in infected samples in comparison with non-infected samples (p < 0.05). Sperm concentration and motility and morphology were significantly lower in infected than non-infected samples. Moreover, sperm DNA fragmentation was significantly higher in infected than non-infected samples. Besides, our results showed that sperm DNA fragmentation was correlated significantly with leukocytospermia (R: 0.22, p < 0.01).

Conclusion

The present study suggested that bacterial infection significantly correlated with leukocytospermia could impair male fertility potential through decreasing sperm motility, morphology, and DNA integrity.

Metabolic Syndrome and Reproduction

Metabolic syndrome (MetS) and infertility are two afflictions with a high prevalence in the general population. MetS is a global health problem increasing worldwide, while infertility affects up to 12% of men. Despite the high prevalence of these conditions, the possible impact of MetS on male fertility has been investigated by a few authors only in the last decade. In addition, underlying mechanism(s) connecting the two conditions have been investigated in few preclinical studies. The aim of this review is to summarize and critically discuss available clinical and preclinical studies on the role of MetS (and its treatment) in male fertility. An extensive Medline search was performed identifying studies in the English language. While several studies support an association between MetS and hypogonadism, contrasting results have been reported on the relationship between MetS and semen parameters/male infertility, and the available studies considered heterogeneous MetS definitions and populations. So far, only two meta-analyses in clinical and preclinical studies, respectively, evaluated this topic, reporting a negative association between MetS and sperm parameters, testosterone and FSH levels, advocating, however, larger prospective investigations. In conclusion, a possible negative impact of MetS on male reproductive potential was reported; however, larger studies are needed.

Dolichandrone serrulata flower extract ameliorates male reproductive damages in type 2 diabetic rats

Dolichandrone serrulata flower (DSF) has been believed to reduce blood glucose in hyperglycaemic persons with sub-fertility but its effect on improvement of male reproductive impairment has never been elucidated scientifically. This study attempted to investigate the hypoglycaemic effects of DSF on male reproductive damages in type 2 diabetes mellitus (T2DM) rats. Adult Sprague Dawley rats were divided into four groups (control, T2DM, DSF200 + T2DM and DSF600 + T2DM; n = 10/each). Control rats received low-fat diet for 14 days before saline injection while streptozocin (50 mg/kg BW) induced T2DM groups received high-fat diet and were orally administered with DSF (200 and 600 mg/kg BW) for 28 days. At the end, fasted blood glucose (FBG), malondialdehyde (MDA), testosterone, sperm quality, histology and protein expressions were examined. The result showed that DSF decreased high FBG and testicular MDA and increased testosterone levels of T2DM-treated rats. Low-sperm quality and histological malfunction were ameliorated in DSF-treated group. There was significant decrease in the expression of androgen receptor, heat-shock 70 and steroidogenic acute regulatory proteins of T2DM-treated rats. Our study demonstrated changes of six bands (116, 51, 45, 39, 35 and 29 kDas) of tyrosine-phosphorylated proteins. In conclusion, DSF could reduce the FBGand ameliorate the reproductive damages in male T2DM rats.

The Sins of Our Forefathers: Paternal Impacts on De Novo Mutation Rate and Development

Spermatogonial stem cells (SSCs) are generally characterized by excellent DNA surveillance and repair, resulting in one of the lowest spontaneous mutation rates in the body. However, the barriers to mutagenesis can be overwhelmed under two sets of circumstances. First, replication errors may generate age-dependent mutations that provide the mutant cells with a selective advantage, leading to the clonal expansions responsible for dominant genetic diseases such as Apert syndrome and achondroplasia. The second mechanism centers on the vulnerability of the male germline to oxidative stress and the induction of oxidative DNA damage in spermatozoa. Defective repair of such oxidative damage in the fertilized oocyte results in the creation of mutations in the zygote that can influence the health and well-being of the offspring. A particular hot spot for such oxidative attack on chromosome 15 has been found to align with several mutations responsible for paternally mediated disease, including cancer, psychiatric disorders, and infertility.

L-Carnitine reduces the negative effects of formalin on sperm parameters, chromatin condensation and apoptosis in mice: An experimental study

Background

Formalin is commonly applied as an antiseptic and tissue fixative. It has reactive molecules that lead to its cytotoxic effects. According to recent studies, formalin causes a change in the testicular and sperm structure and L-carnitine (LC) acts as an antioxidant to counteract its effects.

Objective

This study aimed to investigate the protective effects of LC on the parameters, chromatin condensation and apoptosis of mice sperm exposed to formalin.

Materials and Methods

In this experimental study, 24 balb/c mice (25-40 gr,10-12 wk) were divided into three groups (n = 8/each): group I without any injections or gavage; group II, received 10 mg/ kg formalin intraperitoneally (I.P); and group III was exposed to formalin and LC, where a dose of 10 mg/kg formalin was injected I.P daily and LC the dose of 100 mg/kg was kept in a solvent solution. After 31 days, the sperm examination was performed as follows: to evaluate chromatin and DNA quality of the sperm, we applied aniline blue (AB), toluidine blue (TB), chromomycin A3 (CMA3), and terminal transferase-mediated deoxy uridine triphosphate biotin end labeling (TUNEL) tests.

Results

Sperm parameters such as count, motility, morphology, and viability displayed a significant decrease in the formalin group. While the data exhibited a considerable augment in sperm parameters in the formalin + LC than the formalin and control groups (p < 0.001), significant differences were detected between groups with respect to TB staining, TUNEL test, CMA3 test and AB staining in the formalin and formalin + LC groups.

Conclusion

LC can reduce the negative effects of formalin on sperm parameters, chromatin stability, and percentage of apoptosis in an animal model.

Sperm DNA Fragmentation: A New Guideline for Clinicians

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

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

Background

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

Results

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

Conclusion

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

Comparison of male reproductive parameters in mice with type 1 and type 2 diabetes

OBJECTIVE

The differences between type 1 and type 2 diabetes mellitus (T1DM and T2DM) in terms of their adverse effects on male reproductive parameters have never been elucidated. This study aimed to distinguish between the effects of the DM types in mice treated with multiple low doses of streptozotocin (STZ) to mimic human T1DM and coadministered a high-fat diet (HFD) to mimic human T2DM.

METHODS

The T1DM mice were intraperitoneally injected with STZ (40 mg/kg body weight) for 5 days. The T2DM mice received an HFD for 14 days prior to STZ injection (85 mg/kg body weight), followed by continuous feeding of an HFD. Male reproductive parameters were evaluated.

RESULTS

The reproductive organs of the DM mice weighed significantly less than those of controls, and the seminal vesicles plus prostates of the T1DM mice weighed less than those of the T2DM mice. Increased sperm abnormalities and incomplete DNA packaging were observed in the DM groups. Sperm concentration and the proportion of normal sperm were significantly lower in the T1DM group. The seminiferous histopathology of DM mice was classified into seven types. The penises of the DM mice were smaller than those of the controls; however, tunica albuginea thickness and the amount of penile collagen fibers were increased in these mice. Round germ cells were abundant in the epididymal lumens of the mice with DM.

CONCLUSION

T1DM adversely affected reproductive parameters to a greater extent than T2DM.

Comparison between sperm parameters and chromatin in recurrent pregnancy loss couples after antioxidant therapy

Background and Aims:

Recurrent Pregnancy loss (RPL) is a heterogeneous disease. The role of maternal factor is clear but the relationship between the paternal factors remains uncertain. It has been shown that increase the level of Reactive Oxygen Species (ROS) and decrease the antioxidant levels in men can lead to RPL. New researches show treatment with antioxidant can improved sperm parameter. The aim of the present study was to assess the effect of vitamin E plus Zinc therapy on sperm parameters and chromatin quality in couples with RPL.

Methods:

In this clinical trial study, 60 RPL patients were selected from RPL clinic. Standard sperm parameters were analyzed and then male partners were intake vitamin E and Zinc in antioxidant therapy plan for 90 days. After that, sperm parameters were analyzed again. Sperm chromatin assay was reviewed before and after vitamin E and Zinc therapy by cytochemical assay including aniline blue (AB), chromomycin A3 (CMA3), toluidine blue (TB). To assess DNA fragmentation index, TUNEL test was used. Data were analyzed and compared before and after treatment.

Results:

data analysis showed all sperm parameters significantly improved after treatment (P < 0.001). The number of AB⁺ and TB⁺ sperms were decreased significantly after vitamin E and Zinc therapy (P = 0.0001). Decrease in DNA fragmentation in post treatment group in comparison to pre-treatment was statistically significant.

Conclusion:

Supplemental of vitamin E plus Zinc may improve sperm parameters chromatin quality and decrease sperm DNA fragmentation in RPL patients.

Evaluating the role of paternal factors in aetiology and prognosis of recurrent pregnancy loss: study protocol for a hospital-based multicentre case-control study and cohort study (REMI III project)

INTRODUCTION

Recurrent pregnancy loss (RPL) is defined as the spontaneous demise of two or more pregnancies before the fetus reaches viability. Despite investigation of multiple known maternal risk factors, in more than 50% of couples, this condition remains unexplained. Studies focusing on paternal factors in RPL are scarce, and therefore, paternal evaluation in RPL is currently very limited. However, regarding single miscarriage, there are multiple publications suggesting a contributive role of paternal factors. In this project, we aim to identify paternal factors associated with RPL and to improve couple-specific prediction of future pregnancy outcomes by developing a prediction model containing both maternal and paternal factors.

METHODS AND ANALYSIS

In a case-control design, the relation between unexplained RPL and paternal age, lifestyle factors, sperm DNA damage and immunomodulatory factors in peripheral blood and semen will be studied. Prospectively, 135 couples with naturally conceived unexplained RPL (cases) and 135 fertile couples without a history of pregnancy loss (controls) will be included, with collection of paternal blood and semen samples and documentation of clinical and lifestyle characteristics. In addition, 600 couples from both groups will be included retrospectively. To adjust for confounders, multivariate logistic regression will be used. The predictive value of paternal and maternal factors will be studied in the total RPL cohort consisting of approximately 735 couples. The primary outcome of the cohort study is live birth within 5 years after initial visit of the clinic. Secondary outcomes are ongoing pregnancy, time interval until next pregnancy and pregnancy complications.

ETHICS AND DISSEMINATION

This project is approved by the Medical Research Ethics Committee of the Leiden University Medical Center. No risks or burden are expected from the study. The findings of this study will be disseminated via peer-reviewed publications and presentations at international conferences.

TRIAL REGISTRATION NUMBER

NL7762.

Effects of different doses of tamoxifen on the sperm parameters and chromatin quality in mice: An experimental model

Background

Tamoxifen (TX) is widely used for the treatment of male factor and idiopathic infertility. It has been shown that TX induces sperm production and so improves male fertility.

Objective

This study evaluated the effects of different doses of TX on the sperm parameters and chromatin quality in mice.

Materials and Methods

In this research, 24 male NMRI mice were divided into three groups including group A: control animal receiving vehicle; group B: the group receiving basal diet and TX 0.4 mg/kg/day; and group C: the group receiving basal diet and TX 0.6 mg/kg/day for 35 days. Thereafter, epididymal spermatozoa were analyzed for standard parameters and nuclear chromatin quality using Aniline Blue (AB) and Toluidine Blue (TB) staining.

Results

The results indicated that although the TX did not affect the sperm count, motility, and viability parameters, it could elevate the percentage of sperm cells with abnormal morphology and abnormal chromatin at both doses. In addition, in comparison with the control mice, a significant elevation was observed in spermatozoa with residual histones (assessed by AB staining) at high doses of TX.

Conclusion

Our experimental data in mice suggested that the use of TX for treating male infertility might increase the rates of spermatozoa with abnormal chromatin in a dose-dependent manner.

DNA damaging effect of paclitaxel in the epididymal sperms as a chemotherapeutic agent and possible remedies to prevent this effect: A study on reproductive potential of male cancer patients of reproductive age

Cancer is a major public health problem, young cancer patients therefore undergo chemotherapy, and most of them may lose their fertility. DNA damage level provides important clues about the quality and reproductive potential of spermatozoa. In this study, we evaluated the levels of both DNA fragmentation and abnormal DNA integrity in the epididymal sperms of New Zealand rabbit (Oryctolagus cuniculus) after cryopreservation using the terminal deoxyribonucleotidyl transferase-mediated dUTP nick end-labelling (TUNEL) assay and the toluidine blue (TB) staining methods and assessed the effects of paclitaxel, resveratrol, l-glutamine (LG), and basal medium eagle (BME) solution on DNA damage. Paclitaxel induced the levels of both DNA damages in the sperms, but resveratrol ameliorated this effect. LG and BME supplementation to the extender prevented the sperm samples from DNA fragmentation after cryopreservation. Chemotherapy drugs containing paclitaxel can cause the sperm DNA to be damaged, and hence adversely affect the fertility of male cancer patients of reproductive age. The administration of resveratrol together with paclitaxel may ameliorate the DNA damage inducing effect of paclitaxel. Sperm banking and cryopreservation with the appropriate cryoprotectants such as LG and BME prior to cancer treatment can also be suggested to all male cancer patients of reproductive age facing cancer treatment for fertility preservation.

Cytochemical tests to investigate sperm DNA damage: Assessment and review

Male factor infertility has been diagnosed as the cause of infertility in about 20% of infertile couples. Sperm analysis is the most common method for diagnosing infertility in a laboratory. However, approximately 15% of infertile men have a normal sperm analysis. Therefore, the result of a routine sperm analysis often cannot be a definitive diagnosis for male factor infertility. Also, approximately 8% of infertile men with normal sperm parameters have high levels of abnormal sperm DNA. This indicates the role of the integrity of sperm DNA in male infertility. Here, we review the current tests available to evaluate the sperm DNA integrity along with their benefits and limitations.

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.

Sperm aneuploidy and DNA fragmentation in unexplained recurrent pregnancy loss: a multicenter case-control study

Background

Recurrent pregnancy loss (RPL) is defined as the loss of at least three pregnancies in the first trimester. Although the most common cause is embryo aneuploidy, and despite female checkup and couple karyotyping, in about 50% of cases RPL remain unexplained. Male implication has little been investigated and results are discordant. In this context, we conducted a multi-center prospective case-control study to investigate male gamete implication in unexplained RPL.

Methods

A total of 33 cases and 27 controls were included from three university hospitals. We investigated environmental and family factors with a detailed questionnaire and andrological examination, sperm characteristics, sperm DNA/chromatin status using the sperm chromatin structure assay (SCSA) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and sperm aneuploidy using fluorescence in situ hybridization (FISH). The Mann-Whitney test and the Wilcoxon or Fisher exact tests were used. A non-parametric Spearman correlation was performed in order to analyze the relationship between various sperm parameters and FISH and sperm DNA fragmentation results.

Results

We found significant differences between cases and controls in time to conceive, body mass index (BMI), family history of infertility and living environment. In cases, total sperm motility and the percentage of morphologically normal spermatozoa were significantly decreased. No difference was found between cases and controls in sperm DNA fragmentation or chromatin integrity. In cases, spermatozoa with aneuploidy, hyperhaploidy and chromosome 18 disomy were significantly increased.

Conclusions

This prospective case-control study is one of the largest to examine environmental factors, sperm characteristics, sperm DNA fragmentation and chromatin, and chromosome anomalies in spermatozoa in relation to unexplained recurrent pregnancy loss. The originality of our study lies in the comprehensive andrological examination and search for risk factors and fertility history. Further studies are needed to confirm the links between unexplained RPL and a male family history of infertility or miscarriages. The increased sperm aneuploidy observed in unexplained RPL supports a male etiology. These data pave the way for further studies to demonstrate the value of preimplantation genetic screening in men with increased sperm aneuploidy whose partners experience unexplained RPL.

Sperm chromatin and DNA integrity, methyltransferase mRNA levels, and global DNA methylation in oligoasthenoteratozoospermia

Objective

To investigate sperm chromatin/DNA integrity, global DNA methylation, and DNMT mRNA transcription in men with oligoasthenoteratozoospermia (OAT) compared with normozoospermic men.

Methods

Semen samples from 32 OAT patients who comprised the case group and 32 normozoospermic men who comprised the control group were isolated and purified using a standard gradient isolation procedure according to World Health Organization criteria. DNMT1, DNMT3A, and DNMT3B transcripts were then compared between groups using real-time quantitative reverse-transcription polymerase chain reaction. Global DNA methylation in sperm was determined by an enzyme-linked immunosorbent assay. Protamine deficiency and the proportion of apoptotic spermatozoa were evaluated using chromomycin A3 (CMA3), aniline blue (AB), and toluidine blue (TB) staining, as well as the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The p-values <0.05 were considered to indicate statistical significance.

Results

Significantly higher proportions of AB+, TB+, CMA3+, and TUNEL+ spermatozoa, as well as DNMT3A and DNMT3B transcription, were found in the OAT group. Positive correlations were detected between sperm parameters, DNA/chromatin damage, and DNMT3A and DNMT3B transcripts. Global DNA methylation was significantly higher in the OAT patients and had a significant correlation with abnormal results of all sperm chromatin integrity tests, but was not associated with DNMT1, DNMT3A, or DNMT3B expression.

Conclusion

Oligoasthenoteratozoospermic men showed abnormal sperm parameters, abnormal chromatin/DNA integrity, and a higher global DNA methylation rate, as well as overexpression of DNMT mRNA.

The effect of human sperm chromatin maturity on ICSI outcomes

Because sperm chromatin may play a key role in reproductive success, we verify the associations between sperm chromatin abnormalities, embryo development and the ability to achieve pregnancy. The evaluation of sperm chromatin maturity using aniline blue (AB), chromomycin A3 (CMA3) and toluidine blue (TB) staining were carried out in group of males from infertile couples that underwent ICSI. Low levels of sperm chromatin abnormalities (< 16%) were found in most subjects (> 50%). A higher percentage of TB-positive sperm cells were discovered in the men from couples who achieved ≤ 50% fertilized oocytes compared to men who achieved > 50%. No significant differences were discovered by the applied tests between the men from couples who achieved ≤ 50% and those who achieved > 50% high-quality embryos on the 3rd or 5th day after fertilization, nor between the men from couples who achieved pregnancy and those who failed. The sperm chromatin maturity did not correlate with the ICSI results. However, the ROC analysis revealed a significant predictive value of TB-positive spermatozoa only for fertilization. Therefore, the TB assay can be considered as a useful test for the prediction of fertilization. Our findings suggest that the level of sperm chromatin abnormalities of the examined men was not clinically significant. No found associations between sperm chromatin maturity and embryo development and the ability to achieve pregnancy. We could not exclude the effects of the repairing processes in the fertilized oocyte. The use of complementary tests that verify the status of the sperm chromatin seems justified.

Testicular toxicity and sperm quality following copper exposure in Wistar albino rats: ameliorative potentials of L-carnitine

Copper is a persistent toxic and bio-accumulative heavy metal of global concern. Continuous exposure of copper compounds of different origin is the most common form of copper poisoning and in turn adversely altering testis morphology and function and affecting sperm quality. L-carnitine has a vital role in the spermatogenesis, physiology of sperm, sperm production and quality. This study was designed to examine whether the detrimental effects of long-term copper consumption on sperm quality and testis function of Wistar albino rat could be prevented by L-carnitine therapy. The parameters included were sperm quality (concentration, viability, motility, and morphology), histopathology, serum aspartate aminotransferase (AST), serum alanine aminotransferase (ALT), serum urea, serum creatinine, serum testosterone and testis antioxidant enzyme levels (superoxide dismutase and glutathione-S-transferase), and biomarkers of oxidative stress (lipid peroxidation and expression of heat shock protein 70 in testis). Three-month-old male Wistar rats (n = 30) were divided into six groups as group 1 (G1, 0.9% saline control), group 2 (G2, CuSO4 200 mg/kg dissolved in 0.9% saline water), groups 3 and 4 (G3 and G4, L-carnitine 50 and 100 mg/kg dissolved in 0.9% saline water, respectively), and groups 5 and 6 (G5 and G6, CuSO₄ 200 mg/kg plus L-carnitine, 50 and 100 mg/kg dissolved in 0.9% saline water, respectively). Doses of copper (200 mg/kg) and L-carnitine (50 and 100 mg/kg) alone and in combinations along with untreated control were administered orally for 30 days. The following morphological, physiological, and biochemical alterations were observed due to chronic exposure of copper (200 mg/kg) to rats in comparison with the untreated control: (1) generation of oxidative stress through rise in testis lipid peroxidation (12.21 vs 3.5 nmol MDA equivalents/mg protein) and upregulation of heat shock protein (overexpression of HSP70 in testis), (2) liver and kidney dysfunction [elevation in serum ALT (81.65 vs 48.08 IU/L), AST (156.82 vs 88.25 IU/L), ALP (230.54 vs 148.16 IU/L), urea (12.65 vs 7.45 mmol/L), and creatinine (80.61 vs 48.25 μmol/L) levels], (3) significant decrease in body (99.64 vs 106.09 g) and organ weights (liver-3.48 vs 4.99 g; kidney-429.29 vs 474.78 mg; testes-0.58 vs 0.96 g), (4) imbalance in hormonal and antioxidant enzyme concentrations [significant decline in serum testosterone (0.778 vs 3.226 ng/mL), superoxide dismutase (3.07 vs 8.55 μmol/mg protein), and glutathione-S-transferase (59.28 vs 115.58 nmol/mg protein) levels], (5) severe alterations in the testis histomorphology [sloughed cells (90.65%, score 4 vs 15.65%, score 1), vacuolization (85.95%, score 4 vs 11.45%, score 1), cellular debris along with degenerative characteristics, accentuated germ cell depletion in the seminiferous epithelium, severe damage of spermatogonia and Sertoli cells (73.56%, score 3 vs 0%, score 1)], (6) suppression of spermatogenic process [hypospermatogenesis (low Jhonsen testicular biopsy score 4 vs 9.5), decrease in tubules size (283.75 vs 321.25 μm in diameter), and no. of germ cells (81.8 vs 148.7/100 tubules), Leydig cells (5.2 vs 36.65/100 tubules), and Sertoli cells (8.1 vs 13.5/100 tubules)], (7) sperm transit time was shorter in caput and cauda and ensued in incomplete spermatogenic process and formation of immature sperm leading to infertility, (8) sperm quality was affected significantly [decreased daily sperm production (13.21 vs 26.9 × 10⁶ sperms/mL), sperm count (96.12 vs 154.25 × 10⁶/g), sperm viability (26.88 vs 91.65%), and sperm motility (38.48 vs 64.36%)], and (9) increase of head (32.82 vs 2.01%) and tail (14.85 vs 0.14%) morphologic abnormalities and DNA fragmentation index (88.37 vs 11.11%). Oxidative stress and their related events appear to be a potential mechanism involved in copper testicular toxicity and L-carnitine supplementation significantly modulated the possible adverse effects of copper on seminiferous tubules damage, testes function, spermatogenesis, and sperm quality. It was validated that the use of L-carnitine at doses of 50 and 100 mg/kg protects against copper-induced testicular tissue damage and acts as a therapeutic agent for copper heavy metal toxicity.

Sperm chromatin quality and DNA integrity in partial versus total globozoospermia

Globozoospermia is a severe form of teratozoospermia with low incidence in infertile patients, considered as one of the important causes of male infertility. The objective was to investigate the chromatin/DNA integrity as well as apoptosis in ejaculated spermatozoa of cases with partial or total globozoospermia. Fifty-seven semen samples were divided into three groups of partial globozoospermia (n = 17), total globozoospermia (n = 10) and normozoospermia (control; n = 30). Sperm chromatin condensation, DNA integrity and apoptosis were assessed using cytochemical assays. The results showed significant differences in sperm parameters of count and motility between two case groups versus controls. The percentages of spermatozoa with abnormal chromatin packaging and protamine deficiency were significantly higher in total and partial globozoospermic men compared to normozoospermic samples. Also, the rates of TUNEL-positive spermatozoa were significantly increased in both globozoospermic cases with respect to the control (18.3 ± 10.1 and 12.3 ± 9.2 versus 5.9 ± 3 respectively). However, no significant differences were noticed between two subgroups of patients with regard to sperm DNA denaturation, DNA fragmentation and apoptosis. Abnormal chromatin packaging, DNA damage and apoptosis were significantly higher in cases than controls. The sperm chromatin/DNA anomalies may be considered as one of the main aetiology of ART failure in globozoospermic patients.

A simple sperm DNA toroid integrity test and risk of miscarriage

Current methods of analyzing sperm chromatin competency overlook the inner sperm compartment which is inaccessible to probes and reagents. By breaking the molecular protamine disulfide bridges, the DNA toroids are exposed to integrity analysis. The aim was to develop a simple nuclear toroid test and determine its association with fertilization, pregnancy, and miscarriage. The approach involved treating washed sperm remaining after ICSI procedures (N=35 cases) with acidified Triton X-100 and dithiothreitol (DTT) before Diff-Quik staining. Percentages of sperm with normal chromatin indicated by light-colored nuclei were assessed. The toroid integrity test showed more sperm with normal chromatin in the pregnant group (73.6±1.7%, mean±SEM) when compared with the miscarriage (51.2±6.6%) or nonpregnant groups (60.9±4.8%). Furthermore, the toroid results were correlated with ICSI fertilization (R=0.32, P=0.04) and pregnancy outcome (pregnant cases 73.6±1.7% versus nonpregnant 58.0±3.9%, P=0.001). ROC calculated cut-off was >70.0% for normal toroid integrity (sensitivity 0.98, specificity 0.33, and diagnostic accuracy 78.3%). An association between normal sperm toroid integrity and miscarriage was evident when the staining procedure included acidified detergent DTT pretreatment.

Effect of metformin therapy and dietary supplements on semen parameters in hyperinsulinaemic males

Previous reports indicated that hyperinsulinaemic men may exhibit a higher percentage of poorly compacted DNA in their spermatozoa and less success in an IVF programme (Andrologia, 45, 2003, 18; Andrologia, 2014, doi: 10.1111/and.12227). The aim of this study was to investigate the effect of metformin (Glucophage®) and antioxidant treatment (StaminoGro®) on the semen parameters of hyperinsulinaemic men. Nineteen hyperinsulinaemic male patients were treated for 3 months with metformin alone (Group A), and fifteen patients used metformin in combination with the nutritional supplement (Group B). Combined data of the two groups (pre- and post-treatment) differ significantly regarding sperm morphology (P = 0.0003) and CMA3 (P < 0.0001) values. The improvement in sperm morphology after treatment was similar for the two respective groups (P < 0.05). The morphological normal sperm forms increased from the mean percentage of 3.9 to 5.5% and from 4.2 to 5.5% for Group A and B respectively. Where a combination of metformin and the supplement were used (Group B), the combination treatment proved to be superior in obtaining enhanced chromatin packaging quality although not statistically significant (P = 0.5929) when compared with the metformin (Group A) group. The chromatin packaging quality in Group B improved with 10% while the improvement in Group A was approximately 8.3%. Therefore, infertile hyperinsulinaemic men can benefit from metformin treatment and should be advised on the use of nutritional supplements with antioxidant properties.

Investigation of the association between the outcomes of sperm chromatin condensation and decondensation tests, and assisted reproduction techniques

The main purpose of this prospective study is to examine possible influences of abnormalities of sperm nuclear condensation and chromatin decondensation with sodium dodecyl sulphate (SDS)-EDTA on outcomes of intrauterine insemination (IUI) or intracytoplasmic sperm injection (ICSI) cycles. Semen samples from 122 IUI and 236 ICSI cycles were evaluated. Before semen preparation for IUI or ICSI, basic semen analysis was performed and a small portion from each sample was spared for fixation. The condensation of sperm nuclear chromatin was evaluated with acidic aniline blue, followed by sperm chromatin decondensation by SDS-EDTA and evaluation under light microscope. Ongoing pregnancy rate was 24% and 26.2% in the IUI and ICSI groups respectively. The chromatin condensation rate was significantly higher in the ongoing pregnancy-positive group compared to the negative group, both in IUI (P = 0.042) and ICSI groups (P = 0.027), and it was positively correlated with ongoing pregnancy rate in both IUI and ICSI groups (P = 0.015, r = 0.214 and P = 0.014, r = 0.312 respectively). Chromatin decondensation rates were not significantly different in neither of the groups. These results indicate that IUI and ICSI outcome is influenced by the rate of spermatozoa with abnormal chromatin condensation. Sperm chromatin condensation with aniline blue is useful for selecting assisted reproduction techniques (ART) patients.

CHD5 is required for spermiogenesis and chromatin condensation

Haploid spermatids undergo extensive cellular, molecular and morphological changes to form spermatozoa during spermiogenesis. Abnormalities in these steps can lead to serious male fertility problems, from oligospermia to complete azoospermia. CHD5 is a chromatin-remodeling nuclear protein expressed almost exclusively in the brain and testis. Male Chd5 knockout (KO) mice have deregulated spermatogenesis, characterized by immature sloughing of spermatids, spermiation failure, disorganization of the spermatogenic cycle and abnormal head morphology in elongating spermatids. This results in the inappropriate placement and juxtaposition of germ cell types within the epithelium. Sperm that did enter the epididymis displayed irregular shaped sperm heads, and retained cytoplasmic components. These sperm also stained positively for acidic aniline, indicating improper removal of histones and lack of proper chromatin condensation. Electron microscopy showed that spermatids in the seminiferous tubules of Chd5 KO mice have extensive nuclear deformation, with irregular shaped heads of elongated spermatids, and lack the progression of chromatin condensation in an anterior-to-posterior direction. However, the mRNA expression levels of other important genes controlling spermatogenesis were not affected. Chd5 KO mice also showed decreased H4 hyperacetylation beginning at stage IX, step 9, which is vital for the histone-transition protein replacement in spermiogenesis. Our data indicate that CHD5 is required for normal spermiogenesis, especially for spermatid chromatin condensation.

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.

High-magnification selection of spermatozoa prior to oocyte injection: confirmed and potential indications

Intracytoplasmic morphologically selected sperm injection (IMSI) involves the use of differential interference contrast microscopy at high magnification (at least ·6300) to improve the observation of live human spermatozoa (particularly by showing sperm head vacuoles that are not necessarily seen at lower magnifications) prior to intracytoplasmic sperm injection (ICSI) into the oocyte. However, a decade after IMSI’s introduction, the technique’s indications and ability to increase pregnancy and/or birth rates (relative to conventional ICSI) are subject to debate. In an attempt to clarify this debate, this work performed a systematic literature review according to the PRISMA guidelines. The PubMed database was searched from 2001 onwards with the terms ‘IMSI’, ‘MSOME’ and ‘high-magnification, sperm’. Out of 168 search results, 22 relevant studies reporting IMSI outcomes in terms of blastocyst, pregnancy, delivery and/or birth rates were selected and reviewed. The studies’ methodologies and results are described and discussed herein. In view of the scarcity of head-to-head IMSI versus ICSI studies, the only confirmed indication for IMSI is recurrent implantation failure following ICSI. All other potential indications of IMSI require further investigation.

The impact of semen quality, occupational exposure to environmental factors and lifestyle on recurrent pregnancy loss

PURPOSE

This study aimed to investigate the effect of male semen quality, occupational exposure, and lifestyle on recurrent pregnancy loss (RPL).

METHODS

Information on couples' occupational exposure and lifestyle was collected using a detailed questionnaire from 68 RPL couples and 63 randomly selected healthy controls. Semen parameters were estimated by computer-assisted sperm analysis, and sperm nuclear status was detected with aniline blue (AB) staining.

RESULTS

Patients in the RPL group had significantly lower viability, normal morphology, and total progressive motility of sperm, and a higher mean percentage of AB staining positive sperm compared with those of controls (P < 0.05). There were no differences in sperm concentration, and motility between the groups (P > 0.05). Significant odds ratio (OR) was found when occupational exposure and unhealthy habits were superimposed (OR: 11.965, P = 0.005).

CONCLUSIONS

In addition to standard female factors for evaluating the risk for RPL, the use of male factors should also be taken into consideration. We found that sperm quality, occupational exposure, and lifestyle are factors that affect RPL. Consequently, occupational exposure and lifestyle factors should constitute an important section of questionnaires given to patients, and these factors should be evaluated by a clinician or trained staff.