TUNEL assay-Standardized method for testing sperm DNA fragmentation

Sperm chromatin dispersion assay reliability and assisted reproductive technology outcomes: Systematic review and meta-analysis

OBJECTIVE

Elevated sperm DNA fragmentation has potential implications for semen quality and fertility. The commonly used sperm chromatin dispersion test offers an indirect estimation but has limitations in terms of bias and variability. This study aimed to assess the reliability of the sperm chromatin dispersion assay for predicting assisted reproductive technology outcomes.

MATERIALS AND METHODS

This systematic review included studies published until December 2023 that adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed/MEDLINE, Scopus, and Google Scholar databases were searched. Various assisted reproductive technology outcomes in patients with high (≥ 30%) versus low (< 30%) sperm DNA fragmentation were compared using a sperm chromatin dispersion assay and including a sub-analysis of intracytoplasmic sperm injection versus in vitro fertilization. A comprehensive meta-analysis software facilitated quantitative analysis with statistical comparisons between cases and controls. Interstudy heterogeneity was assessed, and sensitivity and publication bias tests were performed.

RESULTS

Of the 199 abstracts assessed, 64 full-text articles were screened, and 44 articles were qualitatively synthesized. Fourteen articles representing 5346 participants were quantitatively analyzed. Using the sperm chromatin dispersion assay, elevated sperm DNA fragmentation was associated with lower fertilization and embryo cleavage rates. Notably, high sperm DNA fragmentation levels did not affect the clinical pregnancy, implantation, miscarriage, or live birth outcomes. Sub-analysis revealed lower fertilization, embryo cleavage, clinical pregnancy, live birth rates, and higher miscarriage rates in the intracytoplasmic sperm injection subgroup only.

CONCLUSIONS

The sperm chromatin dispersion assay did not show significant differences in pregnancy or live birth rates between the high- and low-sperm DNA fragmentation groups. Noteworthy, high sperm DNA fragmentation was associated with worse assisted reproductive technology outcomes in the intracytoplasmic sperm injection group. Given the current quality of the evidence, affected by the experimental design and the absence of correction for female factors of infertility, clinicians should be wary of the assay's limited predictive power for pregnancy and live birth outcomes.

A 2-step remote TUNEL approach for sperm DNA fragmentation assessment. Analysis in donors and patients

OBJECTIVES

Infertility is a disease of the male or female reproductive systems. Male reproductive workup is based on routine semen analysis, although of limited value. The 2021 WHO Manual incorporated Sperm DNA Fragmentation (SDF) assessment, and highlighted the need for individual laboratories to define suitable thresholds. This study aimed to present an alternative to address this issue, determine an SDF cut-off value with fertile donors, and characterize SDF in a patient cohort and their relationship with semen parameters.

STUDY DESIGN

A service unit was established to remotely perform TUNEL assay in a 2 step-process. Semen samples were received at andrology laboratories, subjected to routine semen analysis (WHO, 2010), partially processed and transported to the service unit for SDF evaluation. Using this setting, studies were done in fertile donors (n = 15) to define the cut-off value, and in men undergoing infertility workup (n = 318).

RESULTS

A cut-off value of 9.17 % was determined with the fertile donor cohort. With this cut-off, a 64.46 % abnormal SDF incidence was determined in the patient cohort. SDF negatively correlated with sperm number, vitality and motility, and positively with abnormal morphology and male age (P < 0.05). TUNEL-positive cases depicted lower sperm quality and higher male age (P < 0.05). A similar abnormal SDF incidence was determined among patients with semen abnormalities. Asthenozoospermic and ≥40 years patient samples depicted higher (P < 0.05) SDF than those of the general population. SDF incidence was also high in normozoospermic patients.

CONCLUSIONS

Using a 2-step remote approach with a standardized procedure and an SDF cut-off value established with fertile donors, high SDF incidence in semen samples depicting normal and abnormal quality were identified in men consulting for infertility, highlighting the relevance of its evaluation as part of the male fertility workup.

The Assessment of Sperm DNA Integrity: Implications for Assisted Reproductive Technology Fertility Outcomes across Livestock Species

Sperm DNA integrity is increasingly considered a useful measure of semen quality in mammalian reproduction. However, the definition of DNA integrity, the ideal means by which it should be measured, and its predictive value for fertility remain a topic of much discussion. With an emphasis on livestock species, this review discusses the assays that have been developed to measure DNA integrity as well as their correlation with in vitro and in vivo fertility.

Effects of Slow Freezing and Vitrification of Human Semen on Post-Thaw Semen Quality and miRNA Expression

Semen cryopreservation has played an important role in medically assisted reproduction for decades. In addition to preserving male fertility, it is sometimes used for overcoming logistical issues. Despite its proven clinical usability and safety, there is a lack of knowledge of how it affects spermatozoa at the molecular level, especially in terms of non-coding RNAs. Therefore, we conducted this study, where we compared slow freezing and vitrification of good- and poor-quality human semen samples by analyzing conventional sperm quality parameters, performing functional tests and analyzing the expression of miRNAs. The results revealed that cryopreservation of normozoospermic samples does not alter the maturity of spermatozoa (protamine staining, hyaluronan binding), although cryopreservation can increase sperm DNA fragmentation and lower motility. On a molecular level, we revealed that in both types of cryopreservation, miRNAs from spermatozoa are significantly overexpressed compared to those in the native semen of normozoospermic patients, but in oligozoospermic samples, this effect is observed only after vitrification. Moreover, we show that expression of selected miRNAs is mostly overexpressed in native oligozoospermic samples compared to normozoospermic samples. Conversely, when vitrified normozoospermic and oligozoospermic samples were compared, we determined that only miR-99b-5p was significantly overexpressed in oligozoospermic sperm samples, and when comparing slow freezing, only miR-15b-5p and miR-34b-3p were significantly under-expressed in oligozoospermic sperm samples. Therefore, our results imply that cryopreservation of normozoospermic sperm samples can modulate miRNA expression profiles in spermatozoa to become comparable to those in oligozoospermic samples.

Improvements in Sperm Motility Following Low- or High-Intensity Dietary Interventions in Men With Obesity

INTRODUCTION

Obesity increases risks of male infertility, but bariatric surgery does not improve semen quality. Recent uncontrolled studies suggest that a low-energy diet (LED) improves semen quality. Further evaluation within a randomized, controlled setting is warranted.

METHODS

Men with obesity (18-60 years) with normal sperm concentration (normal count) (n = 24) or oligozoospermia (n = 43) were randomized 1:1 to either 800 kcal/day LED for 16 weeks or control, brief dietary intervention (BDI) with 16 weeks' observation. Semen parameters were compared at baseline and 16 weeks.

RESULTS

Mean age of men with normal count was 39.4 ± 6.4 in BDI and 40.2 ± 9.6 years in the LED group. Mean age of men with oligozoospermia was 39.5 ± 7.5 in BDI and 37.7 ± 6.6 years in the LED group. LED caused more weight loss than BDI in men with normal count (14.4 vs 6.3 kg; P < .001) and men with oligozoospermia (17.6 vs 1.8 kg; P < .001). Compared with baseline, in men with normal count total motility (TM) increased 48 ± 17% to 60 ± 10% (P < .05) after LED, and 52 ± 8% to 61 ± 6% (P < .0001) after BDI; progressive motility (PM) increased 41 ± 16% to 53 ± 10% (P < .05) after LED, and 45 ± 8% to 54 ± 65% (P < .001) after BDI. In men with oligozoospermia compared with baseline, TM increased 35% [26] to 52% [16] (P < .05) after LED, and 43% [28] to 50% [23] (P = .0587) after BDI; PM increased 29% [23] to 46% [18] (P < .05) after LED, and 33% [25] to 44% [25] (P < .05) after BDI. No differences in postintervention TM or PM were observed between LED and BDI groups in men with normal count or oligozoospermia.

CONCLUSION

LED or BDI may be sufficient to improve sperm motility in men with obesity. The effects of paternal dietary intervention on fertility outcomes requires investigation.

Selection of spermatozoa with high motility and quality from bovine frozen-thawed semen using the centrifuge-free device

This study aimed to assess the potential of the centrifuge-free commercial device (MIGLIS®) in selecting functional frozen-thawed bovine sperm by migration-sedimentation, its effect on embryo development, and compare the potential with that of centrifugation-based techniques, including washing and Percoll density gradient centrifugation (DGC). In experiment 1, different dilutions (1.5×, 2×, and 3×) of frozen-thawed spermatozoa were assessed to identify the adequate one for the MIGLIS method. In experiment 2, the recovery rates, quality, and reactive oxygen species (ROS) concentrations of the spermatozoa selected using MIGLIS, washing, and Percoll DGC were compared. In experiment 3, the resultant in vitro fertilised embryos from spermatozoa selected using the three methods were evaluated for blastocyst formation rates and intracellular ROS concentrations at the 2-4 cell stage. The intracellular ROS concentrations were investigated using 2', 7'-dichlorodihydrofluorescein diacetate staining. Using the MIGLIS device, significantly more spermatozoa were recovered at 2× dilution compared with the other dilution ratio, but the motility was not affected by the dilution ratio. On the selection of spermatozoa using the three methods, employing MIGLIS decreased the recovery rates. However, the MIGLIS method increased motility, viability, and acrosome integrity rates compared to those in spermatozoa from the other methods. The ROS concentration of spermatozoa in the MIGLIS method was significantly lower than that in the washing method. Nevertheless, blastocyst formation rates were similar among the three methods, but the ROS concentration of early-stage embryos produced using MIGLIS was significantly lower than those produced using Percoll DGC. In conclusion, the MIGLIS method has the potential to select functional, high-quality frozen-thawed bovine spermatozoa.

Fluorescent enzyme-based biosensor for sensitive analysis of DNA damage in cryopreserved sperm

The freeze-thaw process can induce irreversible structural and functional changes in human sperm, particularly sperm DNA damage. Selecting a more accurate and sensitive detection method for evaluating sperm DNA integrity is crucial. To accurately assess sperm DNA integrity following the freeze-thaw process and significantly improve the clinical and scientific utilization of cryopreserved sperm. In this study, we utilized a novel fluorescent biosensor, assisted by terminal deoxynucleotidyl transferase (TdT) and Endonuclease IV, to detect DNA breakpoints during sperm cryopreservation. We evaluated the biosensor's performance by comparing it with the conventional DNA fragmentation index (DFI) measured using sperm chromatin structure analysis (SCSA). The cryopreserved group exhibited a significantly higher sperm DFI compared to the fresh group. No significant difference was observed between the antioxidant group and the cryopreserved group. However, the new method revealed a significant reduction in the number of DNA breakpoints in the antioxidant group compared to the cryopreserved group. The novel biosensor demonstrated superior accuracy and effectiveness in assessing sperm DNA integrity during cryopreservation compared to the conventional SCSA method. We believe that the biosensor holds significant potential for widespread use in the field of reproductive medicine.

Novel sperm chromatin dispersion test with artificial intelligence-aided halo evaluation: A comparison study with existing modalities

BACKGROUND

Sperm chromatin dispersion test is a common and inexpensive technique to assess sperm DNA fragmentation, but its subjectivity in assessing a small number of spermatozoa is a disadvantage.

OBJECTIVES

To study the efficacy of a new sperm chromatin dispersion test kit (R10) combined with an artificial intelligence-aided halo-evaluation platform (X12) and compare the results to those of existing sperm DNA fragmentation testing methods.

MATERIALS AND METHODS

Semen samples from normozoospermic donors (n = 10) and infertile men with abnormal semen parameters (n = 10) were enrolled. DNA fragmentation indices were examined by multiple assays, including R10, Halosperm G2 (G2), sperm chromatin structure assay, and terminal deoxynucleotidyl transferase deoxynucleotidyl transferase nick end labeling. In R10 assay, the DNA fragmentation indices were obtained both manually (manual R10) and by X12 (AI-R10). The obtained DNA fragmentation indices were analyzed by agreement analyses.

RESULTS

The DNA fragmentation indices obtained by manual R10 and those obtained by AI-R10 showed a strong significant correlation (r = 0.97, p < 0.001) and agreement. The number of spermatozoa evaluated by AI-R10 was 2078 (680-5831). The DNA fragmentation indices obtained by manual R10 and AI-R10 both correlated with those of G2 (r = 0.90, p < 0.001; r = 0.88, p < 0.001). Between the AI-R10 and G2 results, Passing-Bablok regression showed no systematic or proportional difference, and Bland-Altman plots revealed overall agreement and a mean bias of 6.3% with an SD of 6.9% (95% limit of agreement: -7.2% to 19.9%). AI-R10 and sperm chromatin structure assays showed systematic differences with a mean bias of -1.9%, while AI-R10 and terminal deoxynucleotidyl transferase deoxynucleotidyl transferase nick end labeling revealed proportional differences with a mean bias of -10.7%.

CONCLUSIONS

The novel sperm chromatin dispersion kit and artificial intelligence-aided platform demonstrated significant correlation and agreement with existing sperm chromatin dispersion methods by assessing greater number of spermatozoa. This technique has the potential to provide a rapid and accurate assessment of sperm DNA fragmentation without technical expertise or flow cytometry.

Sperm DNA fragmentation and idiopathic recurrent pregnancy loss: Results from a multicenter case-control study

BACKGROUND

Sperm DNA fragmentation was hypothesized to have a role in the pathogenesis of recurrent pregnancy loss. Unfortunately, the quality of already published evidence is low.

OBJECTIVES

To investigate the association between sperm DNA fragmentation and idiopathic recurrent pregnancy loss by limiting, as much as possible, the interference of confounding factors.

MATERIALS AND METHODS

This was a retrospective multicenter case-control study conducted in two Italian University Hospitals (i.e., Policlinico Gemelli, Rome and Humanitas S. Pio X, Milan) from July 2020 to March 2022. Cases were men belonging to couples affected by first trimester idiopathic recurrent pregnancy loss, defined as the previous loss of two or more pregnancies. Two control groups were selected: (i) men belonging to couples with proven fertility (i.e., at least two previous full-term pregnancies) (control group A); (ii) men belonging to couples with proven infertility (i.e., the failure to achieve a pregnancy after 12 months or more of regular unprotected sexual intercourse) (control group B). The sperm DNA fragmentation index was measured by the terminal deoxynucleotidyl transferase dUTP nick end labeling assay.

RESULTS

We included 74 cases, 37 men with proven fertility (control group A) and 100 men belonging to infertile couples (control group B). The median sperm DNA fragmentation index was significantly lower in control group A (17%, interquartile range: 14.3%-20.6%) compared to both case group (24.5%, interquartile range: 17%-32%; p < 0.0001) and control group B (24%, interquartile range: 18.9%-30%; p = 0.001). The rate of subjects with sperm DNA fragmentation index greater than 30% was significantly higher in both case groups (28%, 95% confidence interval [18%-40%]) and control group B (26%, 95% confidence interval [18%, 36%]) compared to control group A (0%, 95% confidence interval [0%-10%]) (p < 0.001). Multivariate regression models yielded a significant association between sperm DNA fragmentation index and recurrent pregnancy loss (adjusted odds ratio 1.13, 95% confidence interval [1.04-1.23], p = 0.006), but failed to show an association between sperm DNA fragmentation index and infertility (adjusted odds ratio 1.13, 95% CI [1-1.29], p = 0.05).

CONCLUSIONS

Men within couples affected by recurrent pregnancy loss or infertility had a significantly higher rate of sperm DNA fragmentation compared to fertile controls. However, after adjusting for covariates, sperm DNA fragmentation index was associated only with recurrent pregnancy loss.

The effect of hepatic stellate cell derived-IL-11 on hepatocyte injury in hepatic fibrosis

AIMS

This study aimed to elucidate the role of Interleukin-11 (IL-11) in hepatic fibrosis (HF) and its potential as a therapeutic target for HF treatment.

MATERIALS AND METHODS

We investigated IL-11 expression in patients with varying degrees of liver injury through ELISA and immunohistochemistry. A CCl4-induced HF mouse model was constructed to study IL-11 expression and cell apoptosis using Western blotting (WB) and other techniques. The expression of IL-11 was silenced using rAAV8 in the mouse model. In vitro stimulation of hepatic stellate cells (LX-2) with TGF-β1, and of LO-2 cells with exogenous IL-11, were performed. Cell supernatants of TGF-β1-stimulated LX-2 were used to culture LO-2 cells, with apoptosis monitored via flow cytometry and WB.

KEY FINDINGS

Increased IL-11 levels were observed in patients and the HF mouse model, with silencing reducing IL-11 expression. In vitro experiments revealed increased endogenous IL-11 in TGF-β1-stimulated LX-2 cells and an increase in apoptotic index, IL11RA, and gp130 in IL-11-stimulated LO-2 cells. Cell apoptosis was reduced in the siRNA/IL11, siRNA/IL11RA, and anti-IL11 groups. WB and immunohistochemistry results showed upregulated p-JNK, p-ERK, and p-P53 expressions in the CCl4-induced HF mouse model and IL-11-treated LO-2 cells.

SIGNIFICANCE

Our findings suggest IL-11 enhances LX-2 cell activation and proliferation, and promotes LO-2 cell apoptosis through JNK/ERK signaling pathways. This suggests that targeting IL-11 secretion may serve as a potential therapeutic strategy for HF, providing a foundation for its clinical application in HF treatment.

Chronic exposure to warm temperature causes low sperm abundance and quality in Drosophila melanogaster

Temperature influences male fertility across organisms; however, how suboptimal temperatures affect adult spermatogenesis remains understudied. In a recent study on Drosophila melanogaster oogenesis, we observed a drastic reduction in the fertility of adult males exposed to warm temperature (29 °C). Here, we show that males become infertile at 29 °C because of low sperm abundance and quality. The low sperm abundance at 29 °C does not stem from reduced germline stem cell or spermatid numbers, as those numbers remain comparable between 29 °C and control 25 °C. Notably, males at cold 18 °C and 29 °C had similarly increased frequencies of spermatid elongation and individualization defects which, considering the high sperm abundance and male fertility measured at 18 °C, indicate that spermatogenesis has a high tolerance for elongation and individualization defects. Interestingly, the abundance of sperm at 29 °C decreases abruptly and with no evidence of apoptosis as they transition into the seminal vesicle near the end of spermatogenesis, pointing to sperm elimination through an unknown mechanism. Finally, sperm from males at 29 °C fertilize eggs less efficiently and do not support embryos past the first stage of embryogenesis, indicating that poor sperm quality is an additional cause of male infertility at 29 °C.

The Effect of Natural Substances Contained in Bee Products on Prostate Cancer in In Vitro Studies

Prostate cancer is a common cancer in men in older age groups. The WHO forecasts an increase in the incidence of prostate cancer in the coming years. Patients may not respond to treatment, and may not tolerate the side effects of chemotherapy. Compounds of natural origin have long been used in the prevention and treatment of cancer. Flavonoids obtained from natural products, e.g., propolis, are compounds with proven antibacterial and antiviral efficacy which modulate the immune response and may be useful as adjuvants in chemotherapy. The main aim of the present study was to evaluate the cytotoxic and pro-apoptotic properties of selected flavonoids on prostate cancer cells of the LNCaP line. The compounds used in this study were CAPE, curcumin (CUR), and quercetin (QUE). Mitochondrial and lysosome metabolism was assessed by the XTT-NR-SRB triple assay as well as by the fluorescent staining techniques. Staining for reactive oxygen species was performed as well. The experiment showed that each of the tested compounds has a cytotoxic effect on the LNCaP cell line. Different types of cell death were induced by the tested compounds. Apoptosis was induced by quercetin, while autophagy-specific changes were observed after using CAPE. Compounds obtained from other bee products have antiproliferative and cytotoxic activity against LNCaP prostate cancer cells.

Evaluation of Sperm DNA Fragmentation Using Two Different Methods: TUNEL via Fluorescence Microscopy, and Flow Cytometry

Background and Objectives: Sperm DNA fragmentation refers to any break in one or both of the strands of DNA in the head of a sperm. The most widely used methodologies for assessing sperm DNA fragmentation are the sperm chromatin structure assay (SCSA), the sperm chromatin dispersion assay (SCD), the single-cell gel electrophoresis assay (SCGE-comet), and the terminal-deoxynucleotidyl-transferase (TdT)-mediated dUTP nick end labelling (TUNEL) assay. The aim of this study was to compare the efficiency and sensitivity of the analysis of sperm DNA fragmentation using TUNEL via fluorescence microscopy, and flow cytometry. Materials and Methods: Semen samples were collected and analyzed for standard characteristics using light microscopy, and for sperm DNA fragmentation using both TUNEL via fluorescence microscopy, and flow cytometry. Results: There were no significant differences in the values of the sperm DNA fragmentation index (DFI) obtained when the analysis was performed using TUNEL or flow cytometry (p = 0.543). Spearman's correlation analysis revealed a significant negative correlation between sperm motility (%) and sperm DNA fragmentation (p < 0.01), as well as between sperm concentration and sperm DNA fragmentation (p < 0.05). The Mann-Whitney U test showed no significant difference in the DFI among couples with repeated implantation failure (RIF) and miscarriages (p = 0.352). Conclusions: Both methods (TUNEL via fluorescence microscopy, and flow cytometry) have a high efficiency and sensitivity in accurately detecting sperm DNA fragmentation, and can be effectively used to assess male fertility.

Sperm human papillomavirus infection and risk of idiopathic recurrent pregnancy loss: insights from a multicenter case-control study

OBJECTIVE

To test the hypothesis claiming an association between human papilloma virus (HPV) sperm infection and idiopathic recurrent pregnancy loss (RPL).

DESIGN

Multicenter retrospective case-control study.

SETTING

Three university hospitals.

PATIENT(S)

Cases included men belonging to couples affected by first trimester idiopathic RPL. Controls included men belonging to couples with proven fertility and no history of pregnancy loss; RPL was defined as the previous loss of 2 or more pregnancies. Couples were defined as "fertile" if they achieved a full-term pregnancy within the year before enrollment in the study. All participants conceived without assistance.

MAIN OUTCOME MEASURE(S)

The association between HPV DNA sperm infection, as identified using polymerase chain reaction, and RPL.

RESULTS

The HPV DNA sperm infection was detected in 23 of 117 cases (20%; 95% confidence interval [CI]: 13%, 28%) and in 3 of 84 controls (4%; 95% CI; 1%, 10%) (P<.001). A comparison across baseline characteristics and multiple regression analysis did not identify any potentially confounding factors. Multivariate regression models showed a significant association between HPV DNA sperm infection and RPL (adjusted odds ratio, 7.44; 95% CI: 2.08, 26.58; P=.002 [Model 1]; adjusted odds ratio, 8.96; 95% CI: 2.41, 33.44; P=.001 [Model 2]).

CONCLUSIONS

The prevalence of HPV sperm infection was significantly higher in couples affected by RPL than in their fertile counterparts. Notably, the semen sample was infected by HPV in approximately 1 out of 5 patients.

Animal board invited review: An update on the methods for semen quality evaluation in swine - from farm to the lab

Pig breeding is mainly conducted through artificial insemination with liquid-stored semen. It is, therefore, crucial to ensure that sperm quality is over the standard thresholds, as reduced sperm motility, morphology or plasma membrane integrity are associated with reduced farrowing rates and litter sizes. This work aims to summarise the methods utilised in farms and research laboratories to evaluate sperm quality in pigs. The conventional spermiogram consists in the assessment of sperm concentration, motility and morphology, which are the most estimated variables in farms. Yet, while the determination of these sperm parameters is enough for farms to prepare seminal doses, other tests, usually carried out in specialised laboratories, may be required when boar studs exhibit a decreased reproductive performance. These methods include the evaluation of functional sperm parameters, such as plasma membrane integrity and fluidity, intracellular levels of calcium and reactive oxygen species, mitochondrial activity, and acrosome integrity, using fluorescent probes and flow cytometry. Furthermore, sperm chromatin condensation and DNA integrity, despite not being routinely assessed, may also help determine the causes of reduced fertilising capacity. Sperm DNA integrity can be evaluated through direct (Comet, transferase deoxynucleotide nick end labelling (TUNEL) and its in situ nick variant) or indirect tests (Sperm Chromatin Structure Assay, Sperm Chromatin Dispersion Test), whereas chromatin condensation can be determined with Chromomycin A3. Considering the high degree of chromatin packaging in pig sperm, which only have protamine 1, growing evidence suggests that complete decondensation of that chromatin is needed before DNA fragmentation through TUNEL or Comet can be examined.

Sperm DNA Damage and Its Relevance in Fertility Treatment: A Review of Recent Literature and Current Practice Guidelines

Sperm deoxyribonucleic acid (DNA) damage has recently emerged as one of the most controversial topics in male reproductive medicine. While level I evidence indicates that abnormal sperm DNA damage has substantial adverse effects on reproductive outcomes (including chance of pregnancy and risk of miscarriage), there is limited consensus on how sperm DNA fragmentation (SDF) testing should be performed and/or interpreted in clinical practice. In this article, we review: (1) how SDF is assessed, (2) cumulative evidence regarding its impact on reproductive outcomes, (3) methods for mitigating high SDF, and (4) the most recent practice guidelines available for clinicians regarding the use and interpretation of SDF testing.

Sperm DNA fragmentation testing in clinical management of reproductive medicine

Background

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

Methods

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

Main Findings

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

Conclusion

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

Quality of Life Following Pelvic Organ Prolapse Treatments in Women: A Systematic Review and Meta-Analysis

Introduction: Quality of life (QoL) improvement is one of the main outcomes in the management of pelvic organ prolapse as a chronic illness in women. This systematic review aimed to investigate the impact of surgical or pessary treatment for pelvic organ prolapse (POP) on quality of life. Methods: Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was applied. Electronic databases, including PubMed, Scopus, and Web of Science, were searched for original articles that evaluated the QoL before and after surgical interventions or pessary in pelvic organ prolapse from 1 January 2012 until 30 June 2022 with a combination of proper keywords. Included studies were categorized based on interventions, and they were tabulated to summarize the results. Results: Overall, 587 citations were retrieved. Of these, 76 articles were found eligible for final review. Overall, three categories of intervention were identified: vaginal surgeries (47 studies), abdominal surgeries (18 studies), and pessary intervention (11 studies). Almost all interventions were associated with improved quality of life. The results of the meta-analysis showed a significant association between the employment of surgical approach techniques (including vaginal and abdominal surgeries) and the quality of life (Pelvic Floor Distress Inventory (PFDI) (MD: −48.08, 95% CI: −62.34 to −33.77, p-value < 0.01), Pelvic Floor Impact Questionnaire (PFIQ) (MD: −33.41, 95% CI: −43.48 to −23.34, p < 0.01)) and sexual activity of patients with pelvic organ prolapse (Pelvic Organ Prolapse/Urinary Incontinence Sexual Function Questionnaire (PISQ) (MD: 4.84, 95% CI: 1.75 to 7.92, p < 0.01)). Furthermore, narrative synthesis for studies investigating the effect of the pessary approach showed a positive association between the use of this instrument and improvement in the quality of life and sexual activity. Conclusions: The results of our study revealed a significant improvement in the women’s quality of life following abdominal and vaginal reconstructive surgery. The use of pessary was also associated with increased patient quality of life.

Possible Implications of Bacteriospermia on the Sperm Quality, Oxidative Characteristics, and Seminal Cytokine Network in Normozoospermic Men

This study focused on the identification of bacterial profiles of semen in normozoospermic men and their possible involvement in changes to the sperm structural integrity and functional activity. Furthermore, we studied possible fluctuations of selected cytokines, oxidative markers, and antibacterial proteins as a result of bacterial presence in the ejaculate. Sperm motility was assessed with computer-assisted sperm analysis, while sperm apoptosis, necrosis and acrosome integrity were examined with fluorescent methods. Reactive oxygen species (ROS) generation was quantified via luminometry, sperm DNA fragmentation was evaluated using the TUNEL protocol and chromatin-dispersion test, while the JC-1 assay was applied to evaluate the mitochondrial membrane potential. Cytokine levels were quantified with the biochip assay, whilst selected antibacterial proteins were quantified using the ELISA method. The predominant species identified by the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry were Staphylococcus hominis, Staphylococcus capitis and Micrococcus luteus. The results revealed that the sperm quality decreased proportionally to the increasing bacterial load and occurrence of conditionally pathogenic bacteria, including Enterococcus faecalis, Staphylococcus aureus and Escherichia coli. Antimicrobial susceptibility tests revealed a substantial resistance of randomly selected bacterial strains to ampicillin, vancomycin, tobramycin, and tetracycline. Furthermore, an increased bacterial quantity in semen was accompanied by elevated levels of pro-inflammatory cytokines, including interleukin-1, interleukin-2, interleukin-6, tumor necrosis factor alpha as well as ROS overproduction and lipid peroxidation of the sperm membranes. Our results suggest that semen quality may be notably affected by the bacterial quantity as well as quality. It seems that bacteriospermia may be associated with inflammatory processes, oxidative stress, sperm structural deterioration, and a subsequent risk for the development of subfertility, even in normozoospermic males.

Roles of isometric contraction training in promoting neuroprotection and angiogenesis after stroke in adult rats

100 rats were randomly divided into a sham-operated group and middle cerebral artery occlusion (MCAO) modeling groups. The sham group after surgery was observed for 14 days. After MCAO, some rats received isometric contraction training (ICT) which was as follows: an atraumatic tourniquet was placed around left or right hind limb to achieve hind limb ischemia for 5 min, followed by 5 min of reperfusion, 4 cycles for one time, once a day, and five days per week. The MCAO modeling groups included the following four groups: i) a group only received MCAO, and was observed for seven days (MCAO-7d), ii) a group only received MCAO, and was observed for 14 days (MCAO-14d), iii) a group, after MCAO, received ICT for seven days (ICT-7d), and iv) a group, after MCAO, received ICT for 14 days (ICT-14d). Brain infarct area, behavioral outcomes, the number of neurons, apoptosis, cerebral edema and cerebral water content were assessed, respectively. The mRNA expression of vascular endothelial growth factor (VEGF) was assayed with RT-PCR, and protein expression of VEGF was quantified with western blot. compared with MCAO controls, cerebral infarction, neurological deficits and neuronal apoptosis were reduced significantly in the ICT groups, while the number of neurons was increased. Moreover, the mRNA expression of VEGF and protein expression of VEGF were enhanced after 1 and 2 weeks of ICT. ICT may promote angiogenesis and neuroprotection after ischemic stroke and this new remodeling method provide a novel strategy for rehabilitation of stroke patients.

The role of sperm DNA integrity in couples with recurrent implantation failure following IVF treatment

There is increasing evidence from the literature that indicates the association between impaired sperm DNA integrity and male infertility. However, the data is insufficient regarding recurrent implantation failure (RIF) and sperm DNA damage. This study aimed to investigate the association between sperm DNA fragmentation and RIF cases. Basic semen parameters and sperm DNA fragmentation index (DFI) of men whose partner was suffering from RIF were compared with men whose partner was diagnosed with unexplained infertility (UEI) but had clinical pregnancies following IVF treatment. A retrospective analysis from a large-volume IVF center has been performed, and a total of 197 couples underwent analysis. Two groups were formed, couples with RIF and couples diagnosed with UEI but had clinical pregnancies (controls) following IVF cycles. The mean number of cycles showed significant differences between the groups. However, no statistical difference was observed between RIF and the control group regarding patient characteristics, semen parameters, and sperm DNA fragmentation index (DFI). Also, no statistically significant correlation was found between sperm DFI and clinical pregnancies in the unexplained infertility cohort. Our results show that sperm DNA fragmentation may not be an important contributing factor to RIF cases.

pH/Redox/Lysozyme-Sensitive Hybrid Nanocarriers With Transformable Size for Multistage Drug Delivery

The majority of current nanocarriers in cancer treatment fail to deliver encapsulated cargos to their final targets at therapeutic levels, which decreases the ultimate efficacy. In this work, a novel core–shell nanocarrier with a biodegradable property was synthesized for efficient drug release and subcellular organelle delivery. Initially, silver nanoparticles (AgNPs) were grafted with terminal double bonds originating from N, N′-bisacrylamide cystamine (BAC). Then, the outer coatings consisting of chitosan (CTS) and polyvinyl alcohol (PVA) were deposited on the surface of modified AgNPs using an emulsion method. To improve the stability, disulfide-containing BAC was simultaneously reintroduced to cross-link CTS. The as-prepared nanoparticles (CAB) possessed the desired colloidal stability and exhibited a high drug loading efficiency of cationic anticancer agent doxorubicin (DOX). Furthermore, CAB was tailored to transform their size into ultrasmall nanovehicles responding to weak acidity, high glutathione (GSH) levels, and overexpressed enzymes. The process of transformation was accompanied by sufficient DOX release from CAB. Due to the triple sensitivity, CAB enabled DOX to accumulate in the nucleus, leading to a great effect against malignant cells. In vivo assays demonstrated CAB loading DOX held excellent biosafety and superior antitumor capacity. Incorporating all the benefits, this proposed nanoplatform may provide valuable strategies for efficient drug delivery.

Impact of Heat Stress on Bovine Sperm Quality and Competence

Global warming has negatively influenced animal production performance, in addition to animal well-being and welfare, consequently impairing the economic sustainability of the livestock industry. Heat stress impact on male fertility is complex and multifactorial, with the fertilizing ability of spermatozoa affected by several pathways. Among the most significative changes are the increase in and accumulation of reactive oxygen species (ROS) causing lipid peroxidation and motility impairment. The exposure of DNA during the cell division of spermatogenesis makes it vulnerable to both ROS and apoptotic enzymes, while the subsequent post-meiotic DNA condensation makes restoration impossible, harming later embryonic development. Mitochondria are also susceptible to the loss of membrane potential and electron leakage during oxidative phosphorylation, lowering their energy production capacity under heat stress. Although cells are equipped with defense mechanisms against heat stress, heat insults that are too intense lead to cell death. Heat shock proteins (HSP) belong to a thermostable and stress-induced protein family, which eliminate protein clusters and are essential to proteostasis under heat stress. This review focuses on effects of heat stress on sperm quality and on the mechanisms leading to defective sperm under heat stress.

Validated Impacts of N6-Methyladenosine Methylated mRNAs on Apoptosis and Angiogenesis in Myocardial Infarction Based on MeRIP-Seq Analysis

Objectives: N6-methyladenosine (m⁶A) is hypothesized to play a role in the regulation of pathogenesis of myocardial infarction (MI). This study was designed to compare m⁶A-tagged transcript profiles to identify mRNA-specific changes on pathophysiological variations after MI.

Methods: N6-methyladenosine methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA sequencing (RNA-seq) were interacted to select m⁶A-modified mRNAs with samples collected from sham operated and MI rat models. m⁶A methylation regulated mRNAs were interacted with apoptosis/angiogenesis related genes in GeneCards. Afterwards, MeRIP-quantitative real-time PCR (MeRIP-qRT-PCR) was performed to measure m⁶A methylation level of hub mRNAs. m⁶A methylation variation was tested under different oxygen concentration or hypoxic duration in H9c2 cells and HUVECs. In addition, Western blot and qRT-PCR were employed to detect expression of hub mRNAs and relevant protein level. Flow cytometry and Tunel assay were conducted to assess apoptotic level. CCK-8, EdU, and tube formation assay were performed to measure cell proliferation and tube formation ability.

Results: Upregulation of Mettl3 was firstly observed in vivo and in vitro, followed by upregulation of m⁶A methylation level. A total of 567 significantly changed m⁶A methylation peaks were identified, including 276 upregulated and 291 downregulated peaks. A total of 576 mRNAs were upregulated and 78 were downregulated. According to combined analysis of MeRIP-seq and RNA-seq, we identified 26 significantly hypermethylated and downregulated mRNAs. Based on qRT-PCR and interactive analysis, Hadh, Kcnn1, and Tet1 were preliminarily identified as hub mRNAs associated with apoptosis/angiogenesis. MeRIP-qRT-PCR assay confirmed the results from MeRIP-seq. With the inhibition of Mettl3 in H9c2 cells and HUVECs, downregulated m⁶A methylation level of total RNA and upregulated expression of hub mRNAs were observed. Increased m⁶A level was verified in the gradient context in terms of prolonged hypoxic duration and decreased oxygen concentration. Under simulated hypoxia, roles of Kcnn1 and Tet1 in angiogenesis and Hadh, Tet1, and Kcnn1 in apoptosis were further confirmed with our validation experiments.

Conclusion: Roles of m⁶A-modified mRNA transcripts in the context of MI were preliminarily verified. In the context of m⁶A methylation, three hub mRNAs were validated to impact the process of apoptosis/angiogenesis. Our study provided theoretical basis and innovative targets for treatment of MI and paved the way for future investigations aiming at exploring upstream epigenetic mechanisms of pathogenesis after MI.

DNA Damage in Human Amniotic Cells: Antigenotoxic Potential of Curcumin and α-Lipoic Acid

Oxidative imbalances in the gestational phase are responsible for certain complications during pregnancy and for foetal and neonatal genetic disorders. In this work, using human amniocytes, we aimed to evaluate the protection provided to foetal DNA by two concentrations of antioxidant molecules, α-lipoic acid (LA) and curcumin (Cur), against hydrogen peroxide (H₂O₂)-induced damage. Genotoxicity tests, performed by the random amplification of polymorphic DNA (RAPD-PCR) technique and TUNEL tests, showed that the lowest concentration of LA-protected cells and DNA from H₂O₂ insults. However, a greater ability to protect the amniocytes’ DNA against H₂O₂ was observed following co-treatment with the highest concentration of Cur with H₂O₂. In fact, a genomic template stability (GTS%) similar to that of the negative control and a statistically significant reduction in the DNA fragmentation index (DFI) were revealed. Moreover, following a combined treatment with both antioxidants and H₂O₂, no statistical difference from controls was observed, in terms of both induced mutations and DNA breaks. Furthermore, no effect on morphology or cell viability was observed. The results demonstrate the ability of LA and Cur to protect the genetic material of amniocytes against genotoxic insults, suggesting their beneficial effects in pathologies related to oxidative stress.