Sperm DNA fragmentation in Chinese couples with unexplained recurrent pregnancy loss

Prospective reproductive outcomes according to sperm parameters, including DNA fragmentation, in recurrent pregnancy loss

RESEARCH QUESTION

Are the prospective reproductive outcomes in couples experiencing recurrent pregnancy loss (RPL) related to the sperm DNA fragmentation index (DFI), as measured by sperm chromatin structure assay, sperm morphology and sperm concentration at referral?

DESIGN

This prospective cohort study included 95 couples seen between 1 April 2018 and 1 December 2019 at the tertiary Copenhagen RPL Unit, Copenhagen University Hospital, Rigshospitalet and Hvidovre Hospital, Denmark. The couples had experienced three or more unexplained consecutive pregnancy losses or two late pregnancy losses (>12 weeks gestation). Follow-up was 12-31 months.

RESULTS

Eighty-one of 95 (85.3%) couples achieved pregnancy after referral. In the first pregnancy after referral, 46 (56.8%) couples achieved a live birth, and 35 (43.2%) couples experienced another pregnancy loss. There was no significant difference in baseline DFI between couples that experienced pregnancy loss [median 11.7, interquartile range (IQR) 9.1-17.3] and couples that achieved a live birth (median 12.5, IQR 9.3-16.5; P = 0.971). Improving sperm morphology increased the odds of a live birth after referral (adjusted OR 1.26, 95% CI 1.05-1.52; P = 0.014). DFI and sperm concentration were not associated with the outcome of the first pregnancy after referral. Overall, 35.9% of the men had DFI ≥15 at inclusion. Couples that failed to achieve pregnancy had a higher median DFI of 17.7 (IQR 7.7-27.2) compared with the rest of the cohort (median 12.0, IQR 9.3-16.5; P = 0.041).

CONCLUSIONS

At referral, sperm DFI, morphology and concentration cannot be used to identify RPL couples at risk of another pregnancy loss. Increased baseline DFI was associated with difficulty achieving another pregnancy, and improving sperm morphology was associated with increased odds of a live birth.

Poor Sperm Chromatin Condensation Is Associated with Cryopreservation-Induced DNA Fragmentation and Cell Death in Human Spermatozoa

Background/Objectives: Semen cryopreservation is routinely performed in fertility clinics for a variety of reasons, including fertility preservation and storage of donor sperm, yet the freeze-thaw process leads to cellular damage via ice crystal formation, osmotic shock, and supraphysiological levels of oxidative stress. Sperm resistance to damage during the freeze-thaw process varies widely, yet the intrinsic factors associated with sperm cryotolerance are largely unknown. The study aimed to investigate whether poor chromatin condensation renders sperm vulnerable to DNA fragmentation and cell death induced by the freeze-thaw process. Methods: Participants (n = 51) from the general community who met the inclusion criteria collected a semen sample after 3-8 days of abstinence. Neat semen samples underwent traditional semen analysis, aniline blue (AB)-eosin staining for chromatin condensation, the terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay for DNA fragmentation, and the Annexin V assay for apoptosis/necrosis, prior to being cryopreserved using the liquid nitrogen vapour method and stored at -196 °C. Stored samples were later thawed at room temperature and processed using density gradient centrifugation. Motile sperm concentration, DNA fragmentation and apoptosis/necrosis were analysed in post-thaw samples. Results: As indicated by a significant interaction effect in linear mixed models, an increased proportion of AB-positive sperm in the pre-freeze sample exacerbated the adverse effect of freezing on sperm DNA fragmentation (p = 0.004), late apoptosis (p = 0.007), and necrosis (p = 0.007). AB-staining was positively correlated with all three parameters in the post-thaw sample (all rs ≥ 0.424, all p < 0.01) and remained significant after adjusting for neat sperm concentration (all partial rs ≥ 0.493, all p < 0.01). Similarly, AB-staining was significantly correlated with the percentage point change in sperm DNA fragmentation (rs = 0.366, p = 0.014) and necrosis (rs = 0.403, p = 0.009), both of which remained significant after adjusting for neat sperm concentration (both partial rs ≥ 0.404, both p < 0.01), and borderline significantly correlated with percentage point change in late apoptosis (rs = 0.307, p = 0.051). Conclusions: Sperm with poorly condensed chromatin may be more susceptible to cellular damage during the freeze-thaw process, independent of pre-freeze sperm concentration. These findings may help to explain the intrinsic variation in sperm resistance to cryodamage within and between individuals that is poorly understood.

Altered N6-methyladenosine methylation level in spermatozoa messenger RNA of the male partners is related to unexplained recurrent pregnancy loss

BACKGROUND

Understanding the pathogenesis of unexplained recurrent pregnancy loss is paramount for advancing effective treatments. Various biological processes, including spermatogenesis and embryo development, are tightly regulated by N6-methyladenosine modifications. However, few studies have focused on the impact of sperm N6-methyladenosine modifications on embryonic development. Therefore, we aimed to study altered N6-methyladenosine-mediated messenger RNA methylation modifications in the spermatozoa of male partners from couples experiencing unexplained recurrent pregnancy loss, to identify potential diagnostic markers and explore their potential molecular mechanisms in pregnancy loss and embryogenesis.

METHODS

Methylated RNA immunoprecipitation (MeRIP) sequencing and RNA sequencing were conducted on the spermatozoa of men from couples in the 'unexplained recurrent pregnancy loss' group (n = 6), and the fertility control group (n = 6). To identify the role of the detected key genes, zebrafish model embryos were studied, and multi-omics (transcriptomics, proteomics, and metabolomics) analyses helped to explore the molecular mechanism of abnormal embryogenesis.

FINDINGS

Comparing unexplained recurrent pregnancy loss with the fertility control group, 217 N6-methyladenosine peaks were significantly upregulated, and 40 were downregulated in the spermatozoa. The combined analyses of spermatozoa-methylated RNA immunoprecipitation sequencing and RNA sequencing indicated that N6-methyladenosine methylation and the expression of SEMA5A, MT-ATP6, ZNF662, and KDM4C were significantly different. In zebrafish embryos, the altered expression of the four genes increased embryonic mortality and malformations by disturbing several key signaling pathways and zygotic genome activation.

INTERPRETATION

This study highlights the paternal epigenome, which could be one of the reasons for faulty embryogenesis leading to pregnancy loss. The N6-methyladenosine modification, the most prevalent RNA modification, contributes to the exploration and understanding of the paternal epigenome in the maintenance of pregnancy and fetal growth and development. The four genes identified in this study may serve as potential diagnostic markers and elucidate novel molecular mechanisms of embryogenesis.

Association between semen parameters and recurrent pregnancy loss: An umbrella review of meta-analyses

AIM

Recurrent pregnancy loss (RPL) is a common clinical reproductive problem. With research advancements, an increasing number of studies have suggested that male factors play an important role in RPL. However, the evaluation results of male sperm quality in published meta-analyses are inconsistent. We aimed to summarize the evidence of the association between semen factors and RPL and evaluate the level and validity of the evidence.

METHODS

We searched PubMed, Cochrane Library, EMBASE, Web of Science, and Scopus databases for systematic reviews or meta-analyses to evaluate the association between male semen parameters and RPL. The methodological quality of the included meta-analyses was assessed, and data and evidence were re-synthesized and stratified using a random-effects model.

RESULTS

Seven meta-analyses and nine semen parameters were included in the final analysis. The methodological quality of all publications was considered low or very low. There was highly suggestive evidence for the association between sperm DNA fragmentation (SDF), sperm progressive motility rate, and RPL (class II). The evidence level for the association between sperm concentration, normal sperm morphology, sperm deformity rate, total motility, and RPL was suggestive evidence (class III). The evidence level for the association between sperm volume and sperm count and RPL was weak (class IV). There was no significant association between sperm pH and RPL (class NS).

CONCLUSIONS

Our results suggest level II evidence for the association between male SDF and RPL, while the evidence level for the association between conventional semen routine parameters and RPL was low (classes III and IV).

Seminal Oxidative Stress and Sperm DNA Fragmentation in Men from Couples with Infertility or Unexplained Recurrent Pregnancy Loss

(1) Background: This case-control study examined whether men from couples with unexplained recurrent pregnancy loss (RPL) or infertility exhibited higher seminal oxidative stress (OS) and sperm DNA fragmentation (SDF) compared to fertile controls. (2) Methods: The study included 30 participants from each group: unexplained RPL, unexplained infertility, and proven fertility. Data were collected at Aalborg University Hospital tertiary RPL and fertility treatment clinics (Aalborg, Denmark), excluding couples with mixed conditions for homogeneity. Semen samples were analyzed using computer-aided sperm analysis (CASA) for concentration, motility, and morphology. SDF was assessed via a CASA-based sperm chromatin dispersion test. OS was measured as static oxidation-reduction potential (sORP). (3) Results: The results showed no significant OS differences between groups. The RPL group had significantly lower SDF levels than the control group. A significant positive correlation between SDF and OS was observed in the infertility group. Overall, this study did not find significant differences in OS levels between men from couples with unexplained RPL or infertility and fertile controls, while SDF levels were lower in the RPL group compared to controls. (4) Conclusion: In conclusion, despite the existing literature suggesting that OS and SDF are negative prognostic factors, our findings suggest they may not be reliable diagnostic markers for RPL and infertility.

Decreased AKAP4/PKA signaling pathway in high DFI sperm affects sperm capacitation

The sperm DNA fragmentation index (DFI) is a metric used to assess DNA fragmentation within sperm. During in vitro fertilization-embryo transfer (IVF-ET), high sperm DFI can lead to a low fertilization rate, poor embryo development, early miscarriage, etc. A kinase anchoring protein (AKAP) is a scaffold protein that can bind protein kinase A (PKA) to subcellular sites of specific substrates and protects the biophosphorylation reaction. Sperm protein antigen 17 (SPA17) can also bind to AKAP. This study intends to explore the reason for the decreased fertilization rate observed in high sperm DFI (H-DFI) patients during IVF-ET. In addition, the study investigates the expression of AKAP, protein kinase A regulatory subunit (PKARII), and SPA17 between H-DFI and low sperm DFI (L-DFI) patients. SPA17 at the transcriptional level is abnormal, the translational level increases in H-DFI patients, and the expression of AKAP4/PKARII protein decreases. H 2 O 2 has been used to simulate oxidative stress damage to spermatozoa during the formation of sperm DFI. It indicates that H 2 O 2 increases the expression of sperm SPA17 protein and suppresses AKAP4/PKARII protein expression. These processes inhibit sperm capacitation and reduce acrosomal reactions. Embryo culture data and IVF outcomes have been documented. The H-DFI group has a lower fertilization rate. Therefore, the results indicate that the possible causes for the decreased fertilization rate in the H-DFI patients have included loss of sperm AKAP4/PKARII proteins, blocked sperm capacitation, and reduced occurrence of acrosome reaction.

Recurrent pregnancy loss: a male crucial factor-A systematic review and meta-analysis

BACKGROUND

Recurrent pregnancy loss (RPL), defined as two or more failed clinical pregnancies, affects 1%-3% of couples trying to conceive. Nowadays up to 50% of cases remain idiopathic. In this context, paternal factors evaluation is still very limited. The aim is to address the topic of the male factor in RPL with a broad approach, analyzing collectively data on sperm DNA fragmentation (SDF) and semen parameters. We systematically searched in Pubmed/MEDLINE and Google Scholar from inception to February 2023. A protocol has been registered on PROSPERO (ID number CRD42022278616). PRISMA guidelines were followed.

METHODS

Pooled results from 20 studies revealed a higher DNA fragmentation rate in the RPL group compared to controls (mean difference [MD] 9.21, 95% CI 5.58-12.85, p < 0.00001, I2 98%). Age, body mass index (BMI), smoking, and alcohol intake were not associated with DNA fragmentation. Subgroup analysis by different SDF assays (TUNEL and COMET at a neutral pH vs. indirect assessment with other assays) and ethnicity did not highlight different results (p = 0.25 and 0.44).

RESULTS

Results pooled from 25 studies showed a significant difference comparing RPL and control groups regarding ejaculation volume (MD -0.24, 95% CI -0.43; -0.06, p 0.01, I2 66%), total sperm number (MD -10.03, 95% CI -14.65; -5.41, p < 0.0001, I2 76%), total sperm motility (MD -11.20, 95% CI -16.15; -6.25, p < 0.0001, I2 96%), progressive sperm motility (MD -7.34, 95% CI -10.87; -3.80, p < 0.0001, I2 97%), and normal sperm morphology (MD -5.99, 95% CI -9.08; -2.90, p 0.0001, I2 98%). A sub-analysis revealed that Asian and Africans, but not white-European RPL men had lower progressive sperm motility compared to controls.

CONCLUSION

In conclusion, current review and meta-analysis findings suggested that SDF and some specific semen parameters were associated with RPL in a multi-ethnic evaluation. This effort opens future direction on a growing awareness of, first, how the male factor plays a key role and, second, how appropriate would be to establish a direct dialogue between the gynecologist and the urologist.

PATIENT SUMMARY

We performed a systematic review and meta-analysis on the male component of RPL. We found that sperm DNA fragmentation and some specific sperm parameters are significantly associated with RPL.

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.

Sperm quality impairment in males of couples with pregnancy loss is correlated with sexual dysfunction: a cross-sectional study

BACKGROUND

Erectile dysfunction is a common problem in males of couples experiencing pregnancy loss. Erectile dysfunction in males with couple infertile has been extensively investigated and found to be closely linked with semen quality impairment and psychological distress, but it is less clear if this relation exists in males of couples experiencing pregnancy loss.

METHOD

A cross-sectional analysis of 437 men who attended our outpatient clinic between June 2021 and October 2021 for couple pregnancy loss. All subjects underwent a complete physical examination, palpation, inspection of the male genitalia, and semen analysis. Validated assessment tools for erectile dysfunction (the International Index of Sexual Function5 -IIEF-5) and anxiety (the seven-item Generalized Anxiety Disorder Scale- GAD-7) were used.

RESULTS

Among 437 men of couples with pregnancy loss, we found several relevant sperm parameters confirmed a significant correlation between IIEF-5 scores and sperm parameters, including: sperm progressive motility (r = 0.1627, p = 0.001), sperm normal morphology (r = 0.1373, p = 0.004) and sperm DNA fragmentation (r =-0.1248, p = 0.009). Males with an IIEF-5 scores range between 5-11 presented the worst results in terms of sperm progressive motility (p = 0.002), normal morphology (p = 0.001), and SDF levels (p = 0.003). GAD-7 score, as well as anxiety level, was significantly higher in those males with an IIEF-5 score between 5 and 11 (p = 0.000).

CONCLUSION

Although current evidence does not demonstrate the importance of spermatozoa in the etiology of pregnancy loss, significant correlations have been observed between impaired sperm quality and low IIEF-5 scores. Also, anxiety is more likely to occur in males with sexual dysfunction.

The influence of male and female overweight/obesity on IVF outcomes: a cohort study based on registration in Western China

BACKGROUND

Overweight/obesity can affect fertility, increase the risk of pregnancy complications, and affect the outcome of assisted reproductive technology (ART). However, due to confounding factors, the accuracy and uniformity of published findings on IVF outcomes have been disputed. This study aimed to assess the effects of both male and female body mass index (BMI), individually and in combination, on IVF outcomes.

METHODS

This retrospective cohort study included 11,191 couples undergoing IVF. Per the Chinese BMI standard, the couples were divided into four groups: normal; female overweight/obesity; male overweight/obesity; and combined male and female overweight/obesity. The IVF outcomes of the four groups were compared and analysed.

RESULTS

Regarding the 6569 first fresh IVF-ET cycles, compared with the normal weight group, the female overweight/obesity and combined male/female overweight/obesity groups had much lower numbers of available embryos and high-quality embryos (p < 0.05); additionally, the fertilization (p < 0.001) and normal fertilization rates (p < 0.001) were significantly decreased in the female overweight/obesity group. The combined male/female overweight/obesity group had significant reductions in the available embryo (p = 0.002), high-quality embryo (p = 0.010), fertilization (p = 0.001) and normal fertilization rates (p < 0.001); however, neither male or female overweight/obesity nor their combination significantly affected the clinical pregnancy rate (CPR), live birth rate (LBR) or abortion rate (p > 0.05).

CONCLUSION

Our findings support the notion that overweight/obesity does not influence pregnancy success; however, we found that overweight/obesity affects the fertilization rate and embryo number and that there are sex differences.

Sexual dysfunction is more common among men who have high sperm DNA fragmentation or teratozoopermia

Men in couples that have experienced pregnancy loss have a higher risk of sexual dysfunction. Semen quality impairment is common in men of couples with pregnancy loss. The objective of this article is to evaluate the differences in the incidence of male sexual dysfunction in a cohort of pregnancy loss couples with different types of semen quality impairment. A cross-sectional analysis of 426 men who attended our outpatient clinic for couples' pregnancy loss, those without genetic abnormalities were included in the final analysis covering June 2021 to October 2021. The patients were divided into 5 groups according to type of semen quality impairment: normozoospermia group (group normal; N = 161), high sperm DNA fragmentation group (group high-SDF; N = 87), isolated asthenozoospermia group (group iAstheno; N = 45), isolated teratozoopermia group (group iTerato; N = 44), and ≥ 2 abnormal sperm parameters group (group multiple; N = 89). All subjects underwent a complete physical inspection, including palpation of the male genitalia and semen analysis. Validated assessment tools for erectile dysfunction (the International Index of Erectile Function -IIEF-5) and anxiety (the seven-item Generalized Anxiety Disorder Scale- GAD-7) were also used. Men with high sperm DNA fragmentation and isolated teratozoopermia were associated with increased erectile dysfunction risk when compared with normozoospermic men, with an OR of 2.75 [1.49-5.09; p = 0.001] and 2.44 [1.22-5.31; p = 0.024], respectively. It is interesting to note that there was no difference in prevalence of erectile dysfunction between Group iAstheno and Group normal (20.0% vs. 18.0%; OR = 1.24 [0.52-2.97]; P = 0.625). More than half (50.6%) of the participants in Group high-SDF reported sexual intercourse less than once per week, much more than those in the normozoospermia group (23.2%, p < 0.05), followed by Group iTerato (44.4%) and Group multiple (46.1%). GAD-7 scores increased slightly but significantly among groups when compared with Group normal. Not surprisingly, GAD-7 scores remained higher in Group high-SDF. In males of pregnancy loss couples, men with high sperm DNA fragmentation and teratozoopermia suffer from a higher incidence of erectile dysfunction. This phenomenon is not significant in men with isolated asthenozoospermia. Proper counseling and treatment of impaired semen quality are warranted.

Prolonged semen incubation alters the biological characteristics of human spermatozoa

OBJECTIVE

The present study assessed the biological characteristics of human spermatozoa at different time intervals (0, 1, 1.5, and 2 hours) after incubation at 37°C.

METHODS

Twenty-five normozoospermic semen samples were incubated at 37°C. Incubation was performed at four time intervals of 0 (after liquefaction), 1, 1.5, and 2 hours. The samples were evaluated for sperm parameters at each time interval.

RESULTS

The rate of sperm progressive motility decreased at 1.5 hours compared to 0 hours as well as 2 hours compared to 1 hour and 0 hours. The rate of non-motile spermatozoa also decreased after 2 hours compared to after 0 hours. No significant changes were observed in sperm viability (p=0.98) and non- progressive motility (p=0.48) at any time intervals. Abnormal sperm morphology increased at 1.5 hours of incubation time (p<0.001). No significant changes were observed in DNA fragmentation at 1 hour compared to 0 hours (median [interquartile range]: 19.5 [4] vs. 19 [4]), as well as at 1.5 hours compared to 1 hour (20 [5]). However, a significant increase in DNA fragmentation was observed at 1.5 hours compared to 0 hours. The mitochondrial membrane potential decreased remarkably after 1 hour of incubation time. No significant differences were observed in the acrosome reaction or malonaldehyde levels at any time point (p=0.34 and p=0.98, respectively).

CONCLUSION

The incubation of normozoospermic samples before use in assisted reproductive technology should be less than 1.5 hours to minimize the destructive effects of prolonged incubation time on general and specific sperm parameters.

Association of male factors with recurrent pregnancy loss

The role of male factors in recurrent pregnancy loss (RPL) is receiving increased attention since sperm quantity and quality, male genetic mutations, as well as epigenetic modifications, have all been associated with RPL. A growing number of studies have been published on the relationship between male factors and RPL; however, these reports are limited due to small sample sizes, inconsistent inclusion criteria, and detection methods. Herein, we investigate the effects of several male factors on RPL from a genetic and non-genetic perspective to aid clinicians in determining the etiology and optimal treatment strategy for patients with RPL.

Correlation of DNA fragments with routine semen parameters and lifestyle and their impact on assisted reproductive outcomes

OBJECTIVE

This study investigated the correlation between sperm DNA integrity and routine semen evaluation parameters in male infertile patients, the influencing factors, and the impact of the DNA fragmentation index (DFI) on embryo quality and clinical outcomes in in vitro fertilization and embryo transfer (IVF-ET).

METHODS

Sperm DFI and semen routine parameters of 6160 infertile men admitted between June 2017 and June 2018 were analyzed. Patients were divided into three groups according to their DFI: low-DFI (DFI<15%), medium-DFI (15%<DFI≤30%), and high-DFI (DFI>30%). The correlations of DFI with patients' age, sperm concentration, sperm percentage of forward movement and sperm percentage of normal shape were analyzed. The clinical data of 5040 infertile couples who received IVF treatment between June 2016 and 2021 and had embryos transferred in a fresh cycle were reviewed. The fertilization rate, cleavage rate, blastocyst rate, and pregnancy rate in different DFI groups were compared.

RESULTS

Semen evaluation parameters (concentration, spermatozoa with progressive motility, and the normal morphology rate), the high-quality embryo rate, blastocyst development rate, and pregnancy rate in the high-DFI group were significantly lower than those in the other two groups. The correlation analysis revealed that sperm DFI was negatively correlated with semen concentration, sperm motility, and normal sperm morphology and positively correlated with the man's age, BMI, and unhealthy habits (smoking and drinking). There was no significant difference in the number of mature eggs and normal fertilization rate among groups.

CONCLUSION

A strong correlation exists between sperm DFI and semen evaluation parameters. Smoking, drinking, and other unhealthy habits lead to an increase in DFI, reducing the high-quality embryo rate and blastocyst development rate and affecting pregnancy outcomes.

Subclinical Hypothyroidism and Sperm DNA Fragmentation: A Cross-sectional Study of 5401 Men Seeking Infertility Care

CONTEXT

Our previous study showed that paternal subclinical hypothyroidism (SCH) had a detrimental effect on the clinical outcomes of assisted reproductive technologies. However, it remains to be determined whether paternal SCH affects sperm DNA integrity.

OBJECTIVE

To investigate the association between SCH and sperm DNA fragmentation in men seeking infertility care.

METHODS

This cross-sectional study included 4983 men with euthyroidism and 418 men with SCH seeking infertility treatment in a tertiary care academic medical center between January 2017 and December 2021. The outcome measures were the absolute DNA fragmentation index (DFI) and the risk of abnormal DFI (defined as DFI ≥ 25% or ≥ 30%).

RESULTS

The mean (SD) age of men with euthyroidism and men with SCH was 34.20 (5.97) and 35.35 (6.48) years, respectively (P < 0.001). The difference in DFI was not statistically significant (adjusted mean: 19.7% vs 18.9% in the SCH and euthyroidism groups, respectively; P = 0.07) after confounder adjustment. A DFI ≥25% was significantly more frequent in men with SCH (20.57%) than in men with euthyroidism (14.49%) after confounder adjustment [odds ratio (OR) 1.43 (95% CI 1.09-1.88)]. DFI ≥ 30% was also significantly more common in men with SCH (11.72%) than in men with euthyroidism [6.74%; OR 1.84 (95% CI 1.34-2.52)]. In addition, thyroid-stimulating hormone concentration was significantly associated with an increased risk of having a DFI ≥25% (P < 0.001) or ≥30% (P = 0.011).

CONCLUSION

SCH was significantly associated with an increased risk of an abnormal DFI.

A systematic review identifying fertility biomarkers in semen: a clinical approach through Omics to diagnose male infertility

OBJECTIVE

To identify the most robust molecular biomarkers in sperm and seminal plasma for the diagnosis of male infertility, and to evaluate their clinical use.

DESIGN

Systematic review.

SETTING

Not applicable.

PATIENT(S)

Accessible studies reporting well-defined (in)fertile populations and semen molecular biomarkers were included in this review.

INTERVENTION(S)

A systematic search of the literature published in MEDLINE-PubMed and EMBASE databases was performed, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

MAIN OUTCOME MEASURE(S)

The primary outcome was the content, expression, or activity of molecular biomarkers in human semen samples. Only studies reporting a receiver-operating characteristic (ROC) analysis values were included.

RESULT(S)

Eighty-nine studies were included. Direct evaluation of sperm DNA damage has high potential as a diagnostic biomarker of fertility and assisted reproductive technology outcomes (area under the curve [AUCs] median = 0.67). Regarding strand break-associated chromatin modifications, γH2AX levels show good predictive value for the diagnosis of male infertility (AUCs median = 0.93). Some noncoding ribonucleic acid (RNA) exhibit excellent predictive values; miR-34c-5p in semen is the most well-characterized and robust transcriptomic biomarker (AUCs median = 0.78). While many proteins in semen show fair diagnostic value for sperm quality and fertilizing capacity, the levels of some, such as TEX101, in seminal plasma have an excellent diagnostic potential (AUCs median = 0.69). Although individual metabolites and metabolomic profiles in seminal plasma present good predictive value, the latter seem to be better than the former when inferring sperm quality and fertilizing capacity.

CONCLUSION(S)

The current review supports that some Omics (e.g., DNA structure and integrity, genomics and epigenomics, transcriptomics, metabolomics, and proteomics) could be considered relevant molecular biomarkers that may help identify infertility etiologies and fertilization prognosis with cost-effective, simple, and accurate diagnosis.

Impact of Vitamin C on Gene Expression Profile of Inflammatory and Anti-Inflammatory Cytokines in the Male Partners of Couples with Recurrent Pregnancy Loss

Immune system disorders and increased inflammation in the male reproductive system can lead to fetal risk in the early stages of development and implantation. Antioxidants such as vitamin C can play a protective role against sperm inflammatory reactions. This study aimed to evaluate the effect of vitamin C on the expression of inflammatory and anti-inflammatory cytokine genes in the male partners of couples with recurrent pregnancy loss. In this randomized clinical trial, twenty male partners of couples with RPL were examined for sperm parameters and expression profile of some inflammatory and anti-inflammatory cytokine genes before and after treatment with vitamin C. There was a statistically significant higher rate of normal morphology and sperm concentration in each patient before and after treatment with vitamin C (p ≤ 0.05). The mRNA levels of interleukin 6 and tumor necrosis factor-alpha were significantly decreased in the sperm of patients after treatment with vitamin C compared to before treatment. In contrast, the gene expression levels of interleukin 4 and transforming growth factor-beta showed a significant increase in the sperm of patients after treatment with vitamin C. Oral daily administration of vitamin C may be effective in the fertility potential of male partners of couples with RPL not only through the improvement of the sperm parameters but also by modulating the expression profile of inflammatory and anti-inflammatory genes. Further studies on protein levels are needed to clarify the role of TNF-⍺ and IFN-γ as a prognostic value in evaluating the recurrent abortion risk in infertile male partners. This trial is registered with IRCT20180312039059N1.

Influence of sperm DNA fragmentation on the clinical outcome of in vitro fertilization-embryo transfer (IVF-ET)

PURPOSE

To evaluate the effect of elevated sperm DNA fragmentation index (DFI) on fresh and frozen embryo transfer cycles.

METHODS

A retrospective study was performed with 549 fresh embryo transfer cycles and 1340 frozen embryo transfer cycles after in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) from 2016 to 2021.

RESULTS

The statistical results of 549 fresh embryo transfer cycles showed that the delivery rate in the normal sperm DFI group (43.9% vs. 27.1%, P = 0.014) was significantly higher than that in the abnormal sperm DFI group, and there were no significant differences in the biochemical pregnancy rate (59.0% vs. 50.8%, P = 0.232), clinical pregnancy rate (53.1% vs. 40.7%, P = 0.072), or miscarriage rate (17.3% vs. 33.3%, P = 0.098) between the two groups. The results of 1340 frozen embryo transfer cycles showed that the biochemical pregnancy rate (57.9% vs. 45.6%, P = 0.006) and clinical pregnancy rate (50.3% vs. 40.7%, P = 0.027) in the normal sperm DFI group were significantly higher than those in the abnormal sperm DFI group. The delivery rate (40.9% vs. 33.3%, P = 0.074) and miscarriage rate (18.6% vs. 18.0%, P = 0.919) were not significantly different between the two groups.

CONCLUSION

The increase of sperm DFI significantly reduced the delivery rate of fresh embryo transfer cycles and the biochemical pregnancy rate and clinical pregnancy rate of frozen embryo transfer cycles.

Relationship Among Traditional Semen Parameters, Sperm DNA Fragmentation, and Unexplained Recurrent Miscarriage: A Systematic Review and Meta-Analysis

Several studies have explored the relationship among traditional semen parameters, sperm DNA fragmentation (SDF), and unexplained recurrent miscarriage (RM); however, the findings remain controversial. Hence, we conducted a meta-analysis to explore the relationship among traditional semen parameters, SDF, and unexplained RM. Multiple databases, including PubMed, Google Scholar, MEDLINE, Embase, Cochrane Library, Web of Science, and China National Knowledge Infrastructure (CNKI), were searched to identify relevant publications. From the eligible publications, data were extracted independently by two researchers. A total of 280 publications were identified using the search strategy. According to the inclusion/exclusion criteria, 19 publications were eligible. A total of 1182 couples with unexplained RM and 1231 couples without RM were included in this meta-analysis to assess the relationship among traditional semen parameters, SDF, and unexplained RM. Our results showed that couples with unexplained RM had significantly increased levels of SDF and significantly decreased levels of total motility and progressive motility compared with couples without RM, although significant differences were not observed in the semen volume, sperm concentration, and total sperm count between couples with and without RM. The SDF assay may be considered for inclusion in evaluations of couples with unexplained RM.

Sperm genetic abnormalities and their contribution to embryo aneuploidy & miscarriage

Sperm genetic testing has been proposed for clinical diagnosis of possible causes of male infertility. We reviewed the most remarkable publications of sperm DNA integrity and sperm aneuploidy as they relate to clinical outcomes, and the relationship between both genetic defects, and its association to embryo aneuploidy and recurrent pregnancy loss.

Effects of the sperm DNA fragmentation index on the clinical and neonatal outcomes of intracytoplasmic sperm injection cycles

Background

Most studies have mainly focused on the effects of the sperm DNA fragmentation index (DFI) on fertilization, embryonic developmental potential and aneuploidy, pregnancy and abortion rates after in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) and have remained controversial. However, few studies have reported the effects of sperm DFI on neonatal outcomes, including stillbirths, neonatal deaths, sex, gestational age, prematurity, birthweight, low birth weight (LBW) and birth defects in newborns. Our objective was to evaluate the effects of sperm DFI on the clinical and neonatal outcomes of ICSI cycles.

Methods

This retrospective study analysed a total of 2067 oocyte retrieval, 1139 transfer and 713 delivery cycles from conventional ICSI cycles, including 301, 469, and 214 live-born infants in groups segregated according to sperm DFI as the < 15%, 15–30% and >  30% groups, respectively. The clinical and neonatal outcomes were compared among the three groups.

Results

Sperm DFI did not significantly affect the rates of fertilization, clinical pregnancy, miscarriage or ongoing pregnancy. Sperm DFI did not increase the risk of stillbirths or neonatal deaths. The rates of stillbirths and neonatal deaths were not significantly different among the three groups. The sex, gestational age, prematurity, birthweight and LBW of newborns in the three groups were not significantly affected by sperm DFI. Moreover, sperm DFI did not increase the number of birth defects in children.

Conclusions

Sperm DFI did not affect the clinical or neonatal outcomes of ICSI cycles.