The effects of male aging on semen quality, sperm DNA fragmentation and chromosomal abnormalities in an infertile population

A Review of Semen Analysis: Updates From the WHO Sixth Edition Manual and Advances in Male Fertility Assessment

Semen analysis is essentially used to check the fertility of a man, especially when couples are having difficulties conceiving. Studies concerning male fertility, testicular factors, and seminal characteristics have been under investigation for the last few decades. In 1980, the World Health Organization (WHO) started reaching out to scientists in order to set standards for high-quality semen and develop a semen manual. From this point to the present, six editions of this manual have been produced, delineating the characteristics of semen and reporting protocols for semen analysis. Sperm morphology is analyzed as per WHO norms to measure the biological capacity of a male for reproduction. Both national and international manuals have been developed, with the latest, the sixth edition, produced in July 2021. This review paper conveys the current WHO publication's updates and identifies the clinical recommendations for proper evaluations. The publication considers the characteristics of semen in order to discuss the content of the previous editions of the WHO. It is also utilized to assess the method applied to determine the DNA presence of sperm fragmentation.

Paternal Age Amplifies Cryopreservation-Induced Stress in Human Spermatozoa

The global fall in male fertility is a complicated process driven by a variety of factors, including environmental exposure, lifestyle, obesity, stress, and aging. The availability of assisted reproductive technology (ART) has allowed older couples to conceive, increasing the average paternal age at first childbirth. Advanced paternal age (APA), most often considered male age ≥40, has been described to impact several aspects of male reproductive physiology. In this prospective cohort study including 200 normozoospermic patients, 105 of whom were ≤35 years (non-APA), and 95 of whom were ≥42 years (APA), we assessed the impact of paternal age on different endpoints representative of sperm quality and cryopreservation tolerance. Non-APA patients had superior fresh semen quality; DNA fragmentation was notably increased in APA as compared to non-APA individuals (21.7% vs. 15.4%). Cryopreservation further increased the DNA fragmentation index in APA (26.7%) but not in non-APA patients. Additionally, APA was associated with increased mtDNAcn in both fresh and frozen/thawed sperm, which is indicative of poorer mitochondrial quality. Cryopreservation negatively impacted acrosome integrity in both age groups, as indicated by reduced incidences of unreacted acrosome in relation to fresh counterparts in non-APA (from 71.5% to 57.7%) and APA patients (from 75% to 63%). Finally, cryopreservation significantly reduced the phosphorylation status of proteins containing tyrosine residues in sperm from young males. Therefore, the present findings shed light on the effects of paternal age and cryopreservation on sperm quality and serve as valuable new parameters to improve our understanding of the mechanisms underlying sperm developmental competence that are under threat in current ART practice.

Sperm chromatin structure assay (SCSA®) and flow cytometry-assisted TUNEL assay provide a concordant assessment of sperm DNA fragmentation as a function of age in a large cohort of approximately 10,000 patients

BACKGROUND

Sperm DNA integrity is increasingly seen as a critical characteristic determining reproductive success, both in natural reproduction and in assisted reproductive technologies (ART). Despite this awareness, sperm DNA and nuclear integrity tests are still not part of routine examinations for either infertile men or fertile men wishing to assess their reproductive capacity. This is not due to the unavailability of DNA and sperm nuclear integrity tests. On the contrary, several relevant but distinct tests are available and have been used in many clinical trials, which has led to conflicting results and confusion. The reasons for this are mainly the lack of standardization between different clinics and between the tests themselves. In addition, the small number of samples analyzed in these trials has often weakened the value of the analyses performed. In the present work, we used a large cohort of semen samples, covering a wide age range, which were simultaneously evaluated for sperm DNA fragmentation (SDF) using two of the most frequently used SDF assays, namely the TUNEL assay and the sperm chromatin structure assay (SCSA®). At the same time, as standard seminal parameters (sperm motility, sperm morphology, sperm count) were available for these samples, correlations between age, SDF and conventional seminal parameters were analyzed.

RESULTS

We show that the SCSA® and TUNEL assessments of SDF produce concordant data. However, the SDF assessed by TUNEL is systematically lower than that assessed by SCSA®. Regardless of the test used, the SDF increases steadily during aging, while the HDS parameter (High DNA stainability assessed via SCSA®) remains unchanged. In the cohort analyzed, conventional sperm parameters do not seem to discriminate with aging. Only sperm volume and motility were significantly lower in the oldest age group analyzed [50-59 years of age].

CONCLUSIONS

In the large cohort analyzed, SDF is an age-dependent parameter, increasing linearly with aging. The SCSA® assessment of SDF and the flow cytometry-assisted TUNEL assessment are well correlated, although TUNEL is less sensitive than SCSA®. This difference in sensitivity should be taken into account in the final assessment of the true level of fragmentation of the sperm nucleus of a given sample. The classical sperm parameters (motility, morphology, sperm count) do not change dramatically with age, making them inadequate to assess the fertility potential of an individual.

Reappraisal of the Concept of Accelerated Aging in Neurodegeneration and Beyond

BACKGROUND

Genetic and epigenetic changes, oxidative stress and inflammation influence the rate of aging, which diseases, lifestyle and environmental factors can further accelerate. In accelerated aging (AA), the biological age exceeds the chronological age.

OBJECTIVE

The objective of this study is to reappraise the AA concept critically, considering its weaknesses and limitations.

METHODS

We reviewed more than 300 recent articles dealing with the physiology of brain aging and neurodegeneration pathophysiology.

RESULTS

(1) Application of the AA concept to individual organs outside the brain is challenging as organs of different systems age at different rates. (2) There is a need to consider the deceleration of aging due to the potential use of the individual structure-functional reserves. The latter can be restored by pharmacological and/or cognitive therapy, environment, etc. (3) The AA concept lacks both standardised terminology and methodology. (4) Changes in specific molecular biomarkers (MBM) reflect aging-related processes; however, numerous MBM candidates should be validated to consolidate the AA theory. (5) The exact nature of many potential causal factors, biological outcomes and interactions between the former and the latter remain largely unclear.

CONCLUSIONS

Although AA is commonly recognised as a perspective theory, it still suffers from a number of gaps and limitations that assume the necessity for an updated AA concept.

The Effect of Age on Semen Quality Among Male Partners of Infertile Couples: An Observational Study in a Tertiary Care Center in Eastern India

INTRODUCTION

Male infertility contributes to a significant proportion of infertility cases, and advanced paternal age has been suggested to affect semen quality and fertility. However, the relationship between age and semen quality remains inconclusive, with conflicting findings reported in the literature. This study aimed to investigate the effect of age on semen quality among male partners of infertile couples in a tertiary care center in eastern India.

METHODS

A cross-sectional observational study was conducted, involving 390 male participants aged 21-50 years, who were referred to the andrology laboratory for semen analysis between January 2019 and December 2022. Participants were categorized into three age groups (21-30, 31-40, and 41-50 years). Semen parameters, including sperm concentration, semen volume, motility, and morphology, were assessed according to the World Health Organization guidelines.

RESULTS

Among the participants, no significant differences were observed in semen volume, motility, and morphology across different age groups. However, a statistically significant difference in sperm concentration among the three age groups was observed (p = 0.022). Spearman correlation analysis revealed a positive correlation between age and sperm concentration (r = 0.124, p = 0.013) as well as total sperm count (r = 0.10, p = 0.049).

CONCLUSION

In this study, no significant decline in semen quality with age was found among male partners of infertile couples aged 21-50 years. These findings highlight the complex relationship between age and semen quality and emphasize the need for further research to better understand the underlying mechanisms and provide more conclusive evidence regarding the impact of age on male fertility.

Temporal trends in sperm count: a systematic review and meta-regression analysis of samples collected globally in the 20th and 21st centuries

BACKGROUND

Numerous studies have reported declines in semen quality and other markers of male reproductive health. Our previous meta-analysis reported a significant decrease in sperm concentration (SC) and total sperm count (TSC) among men from North America-Europe-Australia (NEA) based on studies published during 1981-2013. At that time, there were too few studies with data from South/Central America-Asia-Africa (SAA) to reliably estimate trends among men from these continents.

OBJECTIVE AND RATIONALE

The aim of this study was to examine trends in sperm count among men from all continents. The broader implications of a global decline in sperm count, the knowledge gaps left unfilled by our prior analysis and the controversies surrounding this issue warranted an up-to-date meta-analysis.

SEARCH METHODS

We searched PubMed/MEDLINE and EMBASE to identify studies of human SC and TSC published during 2014-2019. After review of 2936 abstracts and 868 full articles, 44 estimates of SC and TSC from 38 studies met the protocol criteria. Data were extracted on semen parameters (SC, TSC, semen volume), collection year and covariates. Combining these new data with data from our previous meta-analysis, the current meta-analysis includes results from 223 studies, yielding 288 estimates based on semen samples collected 1973-2018. Slopes of SC and TSC were estimated as functions of sample collection year using simple linear regression as well as weighted meta-regression. The latter models were adjusted for predetermined covariates and examined for modification by fertility status (unselected by fertility versus fertile), and by two groups of continents: NEA and SAA. These analyses were repeated for data collected post-2000. Multiple sensitivity analyses were conducted to examine assumptions, including linearity.

OUTCOMES

Overall, SC declined appreciably between 1973 and 2018 (slope in the simple linear model: -0.87 million/ml/year, 95% CI: -0.89 to -0.86; P < 0.001). In an adjusted meta-regression model, which included two interaction terms [time × fertility group (P = 0.012) and time × continents (P = 0.058)], declines were seen among unselected men from NEA (-1.27; -1.78 to -0.77; P < 0.001) and unselected men from SAA (-0.65; -1.29 to -0.01; P = 0.045) and fertile men from NEA (-0.50; -1.00 to -0.01; P = 0.046). Among unselected men from all continents, the mean SC declined by 51.6% between 1973 and 2018 (-1.17: -1.66 to -0.68; P < 0.001). The slope for SC among unselected men was steeper in a model restricted to post-2000 data (-1.73: -3.23 to -0.24; P = 0.024) and the percent decline per year doubled, increasing from 1.16% post-1972 to 2.64% post-2000. Results were similar for TSC, with a 62.3% overall decline among unselected men (-4.70 million/year; -6.56 to -2.83; P < 0.001) in the adjusted meta-regression model. All results changed only minimally in multiple sensitivity analyses.

WIDER IMPLICATIONS

This analysis is the first to report a decline in sperm count among unselected men from South/Central America-Asia-Africa, in contrast to our previous meta-analysis that was underpowered to examine those continents. Furthermore, data suggest that this world-wide decline is continuing in the 21st century at an accelerated pace. Research on the causes of this continuing decline and actions to prevent further disruption of male reproductive health are urgently needed.

Impact of Advanced Paternal Age on Fertility and Risks of Genetic Disorders in Offspring

The average age of fathers at first pregnancy has risen significantly over the last decade owing to various variables, including a longer life expectancy, more access to contraception, later marriage, and other factors. As has been proven in several studies, women over 35 years of age have an increased risk of infertility, pregnancy problems, spontaneous abortion, congenital malformations, and postnatal issues. There are varying opinions on whether a father's age affects the quality of his sperm or his ability to father a child. First, there is no single accepted definition of old age in a father. Second, much research has reported contradictory findings in the literature, particularly concerning the most frequently examined criteria. Increasing evidence suggests that the father's age contributes to his offspring's higher vulnerability to inheritable diseases. Our comprehensive literature evaluation shows a direct correlation between paternal age and decreased sperm quality and testicular function. Genetic abnormalities, such as DNA mutations and chromosomal aneuploidies, and epigenetic modifications, such as the silencing of essential genes, have all been linked to the father's advancing years. Paternal age has been shown to affect reproductive and fertility outcomes, such as the success rate of in vitro fertilisation (IVF), intracytoplasmic sperm injection (ICSI), and premature birth rate. Several diseases, including autism, schizophrenia, bipolar disorders, and paediatric leukaemia, have been linked to the father's advanced years. Therefore, informing infertile couples of the alarming correlations between older fathers and a rise in their offspring's diseases is crucial, so that they can be effectively guided through their reproductive years.

Extracellular vesicles for precision medicine in prostate cancer - Is it ready for clinical translation?

Biofluid-based biomarker tests hold great promise for precision medicine in prostate cancer (PCa) clinical practice. Extracellular vesicles (EV) are established as intercellular messengers in cancer development with EV cargos, including protein and nucleic acids, having the potential to serve as biofluid-based biomarkers. Recent clinical studies have begun to evaluate EV-based biomarkers for PCa diagnosis, prognosis, and disease/therapy resistance monitoring. Promising results have led to PCa EV biomarker validation studies which are currently underway with the next challenge being translation to robust clinical assays. However, EV research studies generally use low throughput EV isolation methods and costly molecular profiling technologies that are not suitable for clinical assays. Here, we consider the technical hurdles in translating EV biomarker research findings into precise and cost-effective clinical biomarker assays. Novel microfluidic devices coupling EV extraction with sensitive antibody-based biomarker detection are already being explored for point-of-care applications for rapid provision in personalised medicine approaches.

Prediction model for missed abortion of patients treated with IVF-ET based on XGBoost: a retrospective study

Aim

In this study, we established a model based on XGBoost to predict the risk of missed abortion in patients treated with in vitro fertilization-embryo transfer (IVF-ET), evaluated its prediction ability, and compared the model with the traditional logical regression model.

Methods

We retrospectively collected the clinical data of 1,017 infertile women treated with IVF-ET. The independent risk factors were screened by performing a univariate analysis and binary logistic regression analysis, and then, all cases were randomly divided into the training set and the test set in a 7:3 ratio for constructing and validating the model. We then constructed the prediction models by the traditional logical regression method and the XGBoost method and tested the prediction performance of the two models by resampling.

Results

The results of the binary logistic regression analysis showed that several factors, including the age of men and women, abnormal ovarian structure, prolactin (PRL), anti-Müllerian hormone (AMH), activated partial thromboplastin time (APTT), anticardiolipin antibody (ACA), and thyroid peroxidase antibody (TPO-Ab), independently influenced missed abortion significantly (P < 0.05). The area under the receiver operating characteristic curve (AUC) score and the F1 score with the training set of the XGBoost model (0.877 ± 0.014 and 0.730 ± 0.019, respectively) were significantly higher than those of the logistic model (0.713 ± 0.013 and 0.568 ± 0.026, respectively). In the test set, the AUC and F1 scores of the XGBoost model (0.759 ± 0.023 and 0.566 ± 0.042, respectively) were also higher than those of the logistic model (0.695 ± 0.030 and 0.550 ± 049, respectively).

Conclusions

We established a prediction model based on the XGBoost algorithm, which can accurately predict the risk of missed abortion in patients with IVF-ET. This model performed better than the traditional logical regression model.

Defects in sperm capacitation/fertilizing ability are equally prevalent across ages in men seeking fertility assistance

RESEARCH QUESTION

How do capacitation ability, measured by Cap-Score™, and traditional semen analysis measures (volume, concentration, motility) change with age in men questioning their fertility (MQF)?

DESIGN

Cap-Score and semen analysis measures were obtained from MQF (n = 2652; multicentric design: 35 reproductive endocrinologist prescribers, n = 16 clinics). Morphology was not included due to differences among clinics. A Mann-Whitney test was used to compare Cap-Scores between MQF and men with known recent paternity (n = 76). The following age groups were constructed for MQF: 20-24, 25-29, 30-34, 35-39, 40-44, 45-49 and 50+. Associations between semen analysis, Cap-Score and age groups were evaluated using mixed-model analysis of variance to identify possible influence of Cap-Score collection kit type (n = 763 collected at home; n = 1889 collected at clinics).

RESULTS

MQF had reduced capacitation ability (mean ± SE; 29.25 ± 0.15 versus 35.34 ± 0.88; P < 0.001). No change in Cap-Score (P = 0.916) or concentration (P = 0.926) was detected with age group. In contrast, both volume (P = 0.008) and % motility (P < 0.001) declined with age.

CONCLUSIONS

Men presenting because of difficulties in generating pregnancy showed equivalent reductions in capacitation ability regardless of age. In contrast, motility and volume declined with age. These data suggest that capacitation ability is a more sensitive indicator of male fertility across age groups than traditional semen analysis and should not be reserved for older men. Importantly, these data do not address whether sperm fertilizing ability declines in the general population as men age. Instead, they indicate that if men are having difficulty conceiving, no matter what their age, then defects in sperm fertilizing ability are equally likely to be the cause.

Analysis of sperm chromatin packaging and reproductive biomarker to evaluate the consequence of advanced male age

In this study, the semen parameters, sperm chromatin integrity, antioxidant enzyme levels, and reproductive hormone levels of subfertile male subjects from Pakistan were assessed in relation to their age. Data on the demographic characteristics of the 750 study participants, including their general health, body mass index (BMI), and reproductive status, were collected from subfertile men from Pakistan. Semen and blood were collected to determine standard semen parameters, sperm chromatin dispersion (Halosperm-SCD), sperm chromatin integrity using toluidine blue (TB) staining, sperm chromatin maturity using chromomycin A3 (CMA3+) staining, and reproductive hormone (FSH, LH, prolactin and testosterone levels). The patients were divided into three groups according to their age: Group 1 included male subjects aged 30 years or less (n = 90), Group 2 included male subjects between the ages of 31 and 40 years (n = 330), and Group 3 included male subjects over 40 years of age (n = 330). Conventional semen parameters, reactive oxygen species (ROS), superoxide dismutase (SOD), guaiacol peroxidase (GPX), catalase (CAT), and lipid peroxidation (MDA) did not statistically (p > 0.05) differ with increasing male age or between different age groups. When compared to younger men (<30 years), sperm SCD (23.2 ± 0.88%) was significantly (p = 0.01) lower as compared to male patients aged >40 years (26.6 ± 0.6%). The concentration of LH, FSH, and testosterone levels were comparable between the groups (p > 0.05), while a significant (p = 0.04) increase in sperm chromatin immaturity CMA3+ (30 ± 0.71%) was observed in the old age group (>40 years) compared to the <30-year group (26.6 ± 1.03%). A positive association was observed between advanced male age and sperm chromatin dispersion (SCD) (r = 0.124, p = 0.001) and decondensation (CMA3+) (r = 0.1, p = 0.009). Despite potential limitations, this study has been carried out with extensive information on the potential risk of male age on sperm integrity. The present study demonstrated the impact of male age on male reproductive health, as these patients had a higher percentage of sperm chromatin damage (SCD) in their semen. Sperm DNA damage assessment will help in the evaluation and diagnosis of the underlying cause of poor fertility and can help clinicians in selecting the right treatment options. Male age is one of the factors that have an impact on the decline in male fertility. As a result, it is preferable for patients receiving assisted reproductive technology to be younger.

The effect of aging on semen parameters in normozoospermic men: A cross-sectional study

Background

Semen parameters change with age and are reported differently worldwide.

Objective

This retrospective cross-sectional study aimed to investigate the semen quality pattern among aging men and the age thresholds for semen parameters.

Materials and Methods

The records of men who had normal semen parameters from January 2015-June 2020 were retrospectively evaluated for andrological outpatient at Samsun Training and Research hospital and Gazi hospital in Samsun, Turkey. Adult men meeting the inclusion criteria were divided into 3 groups of I) 18-29 yr (n = 629), II) 30-39 yr (n = 775), and III) 40-49 yr (n = 190). Correlations between age and sperm parameters were then analyzed.

Results

A total of 1594 men were enrolled in the study. Significant differences were observed in total sperm numbers, total motility rates, progressive motility rates, nonprogressive motility rates, normal morphology rates, mean semen volume, and sperm concentrations. The parameters of total sperm number, progressive motility rate, and normal morphology rate were significantly higher in group I than in the other 2 groups (p < 0.001, p < 0.001, and p < 0.001, respectively) and in group II compared to group III (p = 0.001, p = 0.003, and p < 0.001), respectively. Mean semen volume and total motility rate were significantly higher in group I than in the other groups (p = 0.001 and p < 0.001, respectively). However, no difference was observed between group II and group III (p = 0.61 and p = 0.04, respectively).

Conclusion

Age has a significant impact on semen parameters capable of affecting male fertility, particularly total sperm numbers, the progressive motility rate, and the normal morphology rate.

Fertility in the aging male: a systematic review

The negative effect of advanced female age on fertility and offspring health is well understood. In comparison, much less is known about the implications of male age on fertility, with many studies showing conflicting results. Nevertheless, increasing evidence suggests that advanced paternal age has negative effects on sperm parameters, reproductive success, and offspring health. Herein, we summarize the current body of knowledge on this controversial topic, with the belief that this review will serve as a resource for the clinicians providing fertility counseling to couples with older male partners.

Impact of caffeic acid on the testicular damages in D-galactose-induced aging model in mice

OBJECTIVES

Aging is a biological phenomenon that causes various disorders and diseases in body systems such as the reproductive system. One of the important factors in aging is oxidative stress, which facilitates the aging process through various mechanisms. The aim of this study is the investigation of effects of caffeic acid on the testicular damages in Dgalactose induced aging model in mice.

MATERIALS AND METHODS

Forty male mice were randomly divided into 5 groups (n=8): 1) Control, 2) Sham, 3) Aging, 4) Aging + caffeic acid, and 5) Caffeic acid. Aging was induced through daily injection of D-Galactose (300 mg/kg, intraperitoneal) for 6 weeks. Caffeic acid (60 mg/kg, intraperitoneal) was injected daily for 6 weeks. One day after the last injection mice were killed and the testicle and epididymis were removed. Then, sperm parameters, factors of oxidative stress, and histopathological changes were evaluated.

RESULTS

The results showed that aging significantly decreased the count, motility, and viability of sperm, and increased abnormal sperm and sperm DNA fragmentation in contrast to the control group (P<0.05). In addition, MDA levels increased significantly in this group, and SOD, GPx, and TAC activity decreased (P<0.05). Histological studies also showed the destruction of seminiferous tubules, and Johnson's score decreased (P<0.05). Caffeic acid administration significantly improved the above disarrays (P<0.05).

CONCLUSION

The results showed that caffeic acid reduces the adverse effects of aging on spermatogenesis in mice by reducing oxidative stress and increasing antioxidant defenses.

Preliminary prediction of semen quality based on modifiable lifestyle factors by using the XGBoost algorithm

Introduction

Semen quality has decreased gradually in recent years, and lifestyle changes are among the primary causes for this issue. Thus far, the specific lifestyle factors affecting semen quality remain to be elucidated.

Materials and methods

In this study, data on the following factors were collected from 5,109 men examined at our reproductive medicine center: 10 lifestyle factors that potentially affect semen quality (smoking status, alcohol consumption, staying up late, sleeplessness, consumption of pungent food, intensity of sports activity, sedentary lifestyle, working in hot conditions, sauna use in the last 3 months, and exposure to radioactivity); general factors including age, abstinence period, and season of semen examination; and comprehensive semen parameters [semen volume, sperm concentration, progressive and total sperm motility, sperm morphology, and DNA fragmentation index (DFI)]. Then, machine learning with the XGBoost algorithm was applied to establish a primary prediction model by using the collected data. Furthermore, the accuracy of the model was verified via multiple logistic regression following k-fold cross-validation analyses.

Results

The results indicated that for semen volume, sperm concentration, progressive and total sperm motility, and DFI, the area under the curve (AUC) values ranged from 0.648 to 0.697, while the AUC for sperm morphology was only 0.506. Among the 13 factors, smoking status was the major factor affecting semen volume, sperm concentration, and progressive and total sperm motility. Age was the most important factor affecting DFI. Logistic combined with cross-validation analysis revealed similar results. Furthermore, it showed that heavy smoking (>20 cigarettes/day) had an overall negative effect on semen volume and sperm concentration and progressive and total sperm motility (OR = 4.69, 6.97, 11.16, and 10.35, respectively), while age of >35 years was associated with increased DFI (OR = 5.47).

Conclusion

The preliminary lifestyle-based model developed for semen quality prediction by using the XGBoost algorithm showed potential for clinical application and further optimization with larger training datasets.

Dietary Lasia spinosa Thw. improves reproductive performance of aged roosters

The application of artificial insemination is particularly, owing to which breeder animals are considered an important resource in breeding farms. However, the reproductive performance of roosters typically declines with age, and the economic loss experienced by breeders is attributable to this shortened reproductive lifespan. Lasia spinosa Thw. (LST) reportedly improved reproductive capacity in male rodents. The objective of this study was to investigate the effects of LST on the reproductive performance of aged roosters. Male Guangxi Partridge chicken (mean weight, 3032.41 ± 34.48 g; age, 500 days; n = 72) randomly received the following three dietary treatments: LST0 group (a basal diet), LST2 group (a basal diet with 2% LST powder), and LST4 group (a basal diet with 4% LST powder). Computer-aided sperm analysis revealed that dietary LST supplementation significantly improved semen volume, sperm motility, and concentration. Furthermore, the most potent effects were observed in the treatment group with the administration of 2% LST, which significantly improved the weight of the testes. Hematoxylin-eosin staining revealed the increase in diameter of the seminiferous tubule and height of the seminiferous tubule epithelium possibly caused as a result of LST treatment. A significant increase in fructose and glucose concentrations were observed in the testis and seminal plasma; in addition, a significant increase was observed in the α-glycosidase levels in the testis and spermatozoa. However, the monoaldehyde levels in the spermatozoa appeared to decline significantly. Additionally, the fertility rate increased significantly following 2% LST supplementation. RNA-seq analysis revealed that 34 and 16 unigenes were upregulated and downregulated, respectively, in testicular tissues from roosters that received dietary supplementation of 2% LST. The assigned functions of the unigenes revealed that LST primarily influenced the mechanisms underlying catalytic activity and cellular processes. Kyoto Encyclopedia of Genes and Genomes enrichment analysis suggested that spermatogenesis-related pathways were significantly enriched, including ABC transporters, ribosome biogenesis in eukaryotes, and VEGF, cAMP, and ErbB signaling pathways.

Correlations between elevated basal sperm DNA fragmentation and the clinical outcomes in women undergoing IUI

OBJECTIVE

This study aimed to explore the impact of the sperm DNA fragmentation index (DFI) on the clinical outcomes in women undergoing artificial insemination by husband intrauterine insemination (AIH-IUI).

METHODS

In this retrospective study, the value of sperm DFI was detected by sperm chromatin structure assay (SCSA) in a semen analysis collected before fertility treatment (basal DFI) in 1,500 IUI cycles at the infertility clinic of Northern Jiangsu People's Hospital Reproductive Medicine Center from Jan 2016 to April 2021. Receiver operating characteristic (ROC) curves were used to calculate the cut-off value for the clinical outcomes of IUI, including the biochemical pregnancy rate, clinical pregnancy rate, delivery rate, and live birth rate, and multivariate logistic regression was conducted to analyse the risk factors for clinical outcomes after IUI.

RESULT

In 1,500 IUI cycles, the results showed that there were no statistically significant differences between the normal DFI group and the abnormal DFI group in biochemical pregnancy rate (14.41% vs. 11.3%, P = 0.386), clinical pregnancy rate (12.9% vs. 10.5%, P = 0.433), delivery rate (11.0% vs. 8.9%, P = 0.456), live birth rate (10.9% vs. 8.9%, P = 0.484) or pregnancy loss rate (14.6% vs. 15.4%, P = 1.000).

CONCLUSION

Sperm DFI alone may have limited predictive power for IUI clinical outcomes.

Association between paternal age and singleton birthweight in frozen embryo transfer cycles

BACKGROUND

Many studies have considered maternal age as a determinant factor for success in assisted reproductive technologies (ART), but the potential role of paternal age on neonatal outcomes has been overlooked. This study aimed to explore the association between paternal age and birthweight in frozen embryo transfer (FET) cycles.

METHODS

This retrospective study involved singleton live births born to women undergoing frozen embryo transfer from January 2013 to December 2017 at a tertiary care center in Shanghai, China. The paternal age was classified into four categories: ≤ 30, 31-35, 36-40, and ≥ 41 years. The group consisting of respondents with paternal age of 31-35 was set as the reference group. Singleton birthweight was the primary outcome measure. Z-scores were calculated according to gestational age and newborn gender on birthweight based on the national birthweight reference. Multivariable linear regression analysis was performed to reveal the relationship between paternal age and newborns' birthweight after considering several potential confounders.

RESULTS

Exactly 9765 women who fulfilled the inclusion criteria were enrolled. No significant difference was found on mean birthweight (P = 0.082) and gestation-adjusted Z-scores (P = 0.569) among paternal age categories. The reference group and the group with aged 36-40 years had the highest mean birthweight and Z-scores, respectively (3350.2 ± 467.8 g, 0.36 ± 1.00). A decline in mean birthweight with paternal age was observed, and the group over 40 years had the lowest value of 3309.4 ± 474.3 g, but the difference was not statistically significant. In multivariate analyses, the adjusted odds of very low birthweight (LBW), LBW, and high birthweight in the reference group did not significantly differ with the three other groups. After correcting several potential confounders, no significant correlation was observed between paternal age and neonatal birthweight (P = 0.289).

CONCLUSION

Paternal age was not associated with mean birthweight and gestational age- and gender-adjusted birthweight (Z-scores) of singletons among women who became pregnant in FET cycles.

The effect of paternal age on intracytoplasmic sperm injection outcome in unexplained infertility

Objective

: To examine the effect of paternal age on intracytoplasmic sperm injection (ICSI) outcomes in unexplained infertility.

Subjects and Methods

: This retrospective study, done at the Hamad Medical Corporation, Doha, Qatar screened infertile couples who underwent ICSI between 2014 and 2019 for the inclusion and exclusion criteria defining 'unexplained infertility'. Couples recruited were allocated into two groups: Group A (paternal age <35 years) and Group B (paternal age ≥35 years). Baseline characteristics, investigations including semen and advanced sperm function tests and ICSI records were compared for primary outcomes such as fertilisation, cleavage, clinical pregnancy, miscarriage and live birth; and secondary outcomes such as semen parameters and advanced sperm functions (DNA fragmentation index and oxidation reduction potential).

Results

: We found that final pregnancy outcomes including clinical pregnancy rate (P = 0.231), live-birth rate (P = 0.143), and miscarriage rates (P = 0.466) were not significantly different between the two age groups. Normal fertilisation (P = 0.01) and cleavage rate after ICSI (P = 0.001) were statistically significant when the age groups were compared. Also, normal sperm morphology was found to be significantly different (P = 0.041).

Conclusions

: Advanced paternal age affects sperm morphology, fertilisation and embryo cleavage in ICSI but does not appear to affect clinical pregnancy, miscarriage or live-birth rates. ICSI appears to be a valid fertility treatment option in advancing paternal age.

Role of sperm apoptosis and oxidative stress in male infertility: A narrative review

Activation of caspase, externalization of phosphatidyl serine, change in the mitochondrial membrane potential, and DNA fragmentation are apoptosis markers found in human ejaculated spermatozoa. Also, reactive oxygen species (ROS) play a vital role in the different types of male infertility. In this review, data sources including Google Scholar, Scopus, PubMed, and Science Direct were searched for publications with no particular time restriction to get a holistic and comprehensive view of the research. Apoptosis regulates the male germ cells, correct function and development from the early embryonic stages of gonadal differentiation to fertilization. In addition to maintaining a reasonable ratio between the Sertoli and germ cells, apoptosis is one of the well-known quality control mechanisms in the testis. Also, high ROS levels cause a heightened and dysregulated apoptotic response. Apoptosis is one of the well-known mechanisms of quality control in the testis. Nevertheless, increased apoptosis may have adverse effects on sperm production. Recent studies have shown that ROS and the consequent oxidative stress play a crucial role in apoptosis. This review aims to assimilate and summarize recent findings on the apoptosis in male reproduction and fertility. Also, this review discusses the update on the role of ROS in normal sperm function to guide future research in this area.

Correlation between sperm DNA fragmentation index and semen parameters in 418 men seen at a fertility center

Objective:

Methods:

Results:

Conclusions:

The effect of sperm DNA fragmentation on intracytoplasmic sperm injection outcome

Our study objective was to assess the effect of various sperm DNA fragmentation levels on clinical intracytoplasmic sperm injection outcome. This retrospective study included 392 patients who underwent ICSI and performed sperm DNA fragmentation testing before the procedure. Based on sperm DNA fragmentation cut-off values, the patients were differentiated into 3 groups as <20%, 20%-30% and >30%. According to the female status, patients were differentiated into favourable group (n = 259) with female age <35 years and anti-Mullerian hormone level ≥7.1 pmol/L; and unfavourable group (n = 133) with female age ≥35 years and anti-Mullerian hormone level ≤7.1 pmol/L. The patient's medical records were reviewed, and patient's demographic, laboratory data including semen analysis, sperm DNA fragmentation determined by means of sperm chromatin dispersion, hormonal profile and data regarding intracytoplasmic sperm injection cycle were collected. This cohort reported that the clinical reproductive outcomes of intracytoplasmic sperm injection showed no statistical significance with increase sperm DNA fragmentation levels. In sperm DNA fragmentation above 30%, favourable females had significantly higher clinical pregnancy rate and live birth rate than unfavourable females, while fertilisation rate and miscarriage rate showed no significance between the subgroups. High sperm DNA fragmentation is linked to poor semen parameters.

Advanced Paternal Age and Sperm DNA Fragmentation: A Systematic Review

Purpose

Male ageing is often associated with defective sperm DNA remodeling mechanisms that result in poorly packaged chromatin and a decreased ability to repair DNA strand breaks. However, the impact of advanced paternal age on DNA fragmentation remains inconclusive. The aim of the present systematic review was to investigate the impact of advancing paternal age (APA) on DNA fragmentation.

Materials and Methods

We conducted a thorough search of listed publications in Scopus, PubMed, and EMBASE, in accordance with the PRISMA guidelines.

Results

We identified 3,120 articles, of which nineteen were selected for qualitative analysis, resulting in a sample of 40,668 men. Of the 19 articles evaluating the impact of APA on DFI% (DNA fragmentation Index) included, 4 were on Normozoospermic and subfertile men, 3 on normozoospermic, Oligoasthenoteratozoospermic and Teratozoospermic, 6 on fertile and infertile men, 4 on just infertile men, and 2 evaluated a general population. Seventeen of the ninrnteen studies demonstrated APA's effect and impact on DFI%.

Conclusions

Although there was no universal definition for APA, the present review suggests that older age is associated with increased DFI. In elderly men with normal semen parameters, further studies should be performed to assess the clinical implications of DFI, as a conventional semen analysis can often fail to detect an etiology for infertility.

Sperm DNA fragmentation and male fertility: a retrospective study of 5114 men attending a reproductive center

PURPOSE

The sperm DNA fragmentation index (DFI) was quantitatively measured and its relationship with age, semen quality, and infertility conditions was investigated.

METHODS

Semen routine test and sperm DFI were performed in 2760 infertile male and 2354 male whose spouse experienced at least one unexplained miscarriage to analyze the correlation between sperm DNA damage, semen routine parameters, and age.

RESULTS

Sperm DFI was significantly lower from patients whose wife experienced unexplained miscarriage compared to infertility males (p = 0.000). An inverse correlation between sperm DFI and sperm progressive motility was observed (r_s = - 0.465, p = 0.000) and sperm DFI was positively correlated with age (r_s = 0.255, p = 0.000). However, the correlation between sperm DFI and sperm concentration, semen volume, total sperm count, and motile sperm count were not proved.

CONCLUSIONS

Sperm DFI is an important indicator for evaluating the quality of semen. Sperm DNA integrity testing is preferentially recommended to those who have decreased sperm progressive motility, especially older men. An integrative analysis of sperm DFI, sperm progressive motility, age, and infertility conditions can provide a more comprehensive assessment of male fertility.

Age-related changes in human conventional semen parameters and sperm chromatin structure assay-defined sperm DNA/chromatin integrity

RESEARCH QUESTION

What are the correlations between male age, traditional semen parameters, sperm DNA fragmentation index (DFI) and high DNA stainability (HDS) in a sufficiently large sample size?

DESIGN

Retrospective cohort study of 18,441 semen samples, with data divided into seven age groups according to male age: ≤25, 26-30, 31-35, 36-40, 41-45, 46-50 and ≥51 years.

RESULTS

Age was negatively correlated with semen volume, total sperm count, motility and HDS, and positively correlated with sperm concentration and DFI (P < 0.001). After 35 years of age, semen volume and total sperm count began to decline. After 30 years of age, motility and HDS decreased consistently. Sperm concentration and DFI increased from 26-30 years of age. DFI was negatively correlated with sperm concentration, total sperm count, motility and normal morphology (P < 0.001) and positively correlated with semen volume and HDS (P < 0.001). HDS was negatively correlated with all parameters (P < 0.001) except semen volume (r = -0.013, P = 0.074) and DFI (r = 0.124, P < 0.001). Patients aged ≥40 years had higher DFI than those aged <40 years in the entire cohort, in the abnormal semen parameters cohort, and in the normal semen parameters cohort (OR 2.145, 2.042, 1.948, respectively, P < 0.001). The ≥40 years age group had a lower HDS than the <40 years age group in the entire cohort and abnormal semen parameters cohort (OR 0.719, 0.677, respectively, P < 0.001).

CONCLUSIONS

Ageing is a negative effector of sperm quantity and quality, and routine sperm parameters have weak but significant correlations with sperm DNA/chromatin integrity.

The complex relationship between female age and embryo euploidy

BACKGROUND

Female age is the strongest predictor of embryo chromosomal abnormalities and has a nonlinear relationship with the blastocyst euploidy rate: with advancing age there is an acceleration in the reduction of blastocyst euploidy. Aneuploidy was found to significantly increase with maternal age from 30% in embryos from young women to 70% in women older than 40 years old. The association seems mainly due to chromosomal abnormalities occurring in the oocyte. We aimed to elaborate a model for the blastocyst euploid rate for patients undergoing in-vitro fertilization/intra cytoplasmic sperm injection (IVF/ICSI) cycles using advanced machine learning techniques.

METHODS

This was a retrospective analysis of IVF/ICSI cycles performed from 2014 to 2016. In total, data of 3879 blastocysts were collected for the analysis. Patients underwent PGT-Aneuploidy analysis (PGT-A) at the Center for Reproductive Medicine of European Hospital (Rome, Italy) have been included in the analysis. The method involved whole-genome amplification followed by array comparative genome hybridization. To model the rate of euploid blastocysts, the data were split into a train set (used to fit and calibrate the models) and a test set (used to assess models' predictive performance). Three different models were calibrated: a classical linear regression; a gradient boosted tree (GBT) machine learning model; a model belonging to the generalized additive models (GAM).

RESULTS

The present study confirms that female age, which is the strongest predictor of embryo chromosomal abnormalities, and blastocyst euploidy rate have a nonlinear relationship, well depicted by the GBT and the GAM models. According to this model, the rate of reduction in the percentage of euploid blastocysts increases with age: the yearly relative variation is -10% at the age of 37 and -30% at the age of 45. Other factors including male age, female and male Body Mass Index, fertilization rate and ovarian reserve may only marginally impact on embryo euploidy rate.

CONCLUSIONS

Female age is the strongest predictor of embryo chromosomal abnormalities and has a non-linear relationship with the blastocyst euploidy rate. Other factors related to both the male and female subjects may only minimally affect this outcome.

Testicular transcriptome analysis under the dietary inclusion of l-carnitine reveals potential key genes associated with oxidative defense and the semen quality factor in aging roosters

l-carnitine (LC) has been widely studied as a natural antioxidant molecule for treating low-fertility gametes. However, the molecular mechanism of the effect of LC supplementation on the testes of aging cocks has not been evaluated. Therefore, the objective of this study was to reveal the mechanism of testicular oxidative defense induced by LC supplementation in relation to the semen quality factor (SQF) in the aging cock through a transcriptome study conducted from a new perspective. A total of 24 Jinghong cocks at 55 wk of age were randomly divided into 2 groups (n = 12). All cocks were fed a standard isocaloric and isonitrogenic breeder diet (control, LC-0), and the other group was supplemented with LC at 150 mg/kg/d (treated, LC-150) for 12 wk. Remarkably, seminal characteristics and enzymes, sex hormones, and cock fertility related to testicular oxidative defense were considerably improved by LC supplementation. LC-150 testes showed the differential upregulation and downregulation of 97 and 90 transcripts, respectively, compared with LC-0 testes. Most upregulated transcripts were involved in testicular oxidative defense and spermiogenesis optimization, whereas the downregulated genes were responsible for oxidative stress, in contrast to the SQF. Functional analysis of the transcriptionally altered genes indicated the testicular deregulation of long-chain fatty acid and lipid peroxidation, enhancing fatty acid breakdown to release ATP production via β-oxidation. These findings could lay the foundation for the discovery of new molecular markers of SQF-associated LC supplementation and potential targets for therapeutic intervention to optimize fertility in aging cocks.

Advanced paternal age: effects on sperm parameters, assisted reproduction outcomes and offspring health

Many factors, including postponement of marriage, increased life expectancy, and improved success with assisted reproductive technologies have been contributing to increased paternal age in developed nations. This increased average paternal age has led to concerns about adverse effects of advanced paternal age on sperm quality, assisted reproductive outcomes, and the health of the offspring conceived by older fathers. This review discusses the association between advanced paternal age and sperm parameters, assisted reproduction success rates, and offspring health.

Paternal Age Does Not Influence the Outcomes of Assisted Reproduction in Donor Oocyte Cycles

Purpose: To study effect of paternal age on pregnancy outcomes of intracytoplasmic sperm injections (ICSI).

Methods: The present study is a retrospective analysis of 153 ICSI cycles on donor oocytes. The effect of paternal age on fertilization rates, implantation rates, total pregnancy rates, number of miscarriages and live births were analyzed.

Results: 1422 donor oocytes were injected with sperm from 153 men. Linear regression analysis revealed no association between paternal age (28-54 years) and fertilization rate. No association was found between the embryo quality and paternal age. Of the 359 embryos transferred, linear regression analysis revealed no association between paternal age and implantation rate. After correcting for maternal age, binary logistic regression analysis revealed no association between total pregnancy rates (B = 0.943, CI 0.861-1.033, P = 0.205), live birth rates (B = 1.018, CI 0.896-1.158, P = 0.562) and miscarriage rates (B = 0.944, CI 0.866-1.029, P = 0.193) and paternal age.

Conclusion: Paternal age does not seem to influence outcomes in assisted reproduction.

Paternal age, body mass index, and semen volume are associated with chromosomal aberrations-related miscarriages in couples that underwent treatment by assisted reproductive technology

We investigated the effects of paternal characteristics, including age, body mass index (BMI), and semen parameters on chromosomal aberration-related miscarriages in couples that underwent treatment with assisted reproductive technology (ART). Single nucleotide polymorphism (SNP) array analysis showed chromosomal aberrations in 60.2% (557/925) of miscarried fetuses, including trisomy in 73.1% (407/557) of cases. There were higher chromosomal aberration rates in fetuses for men aged 20-24 years and ≥30 years compared with controls. After adjusting for age and BMI of the female partners, and the BMI and semen parameters of the males, there was no statistically significant effect of paternal age ≥30 years on the risk of chromosomal aberrations-related miscarriages. However, the odds of chromosomal abnormality-related miscarriage were 148% higher for the youngest fathers (age: 20-24 years) than fathers aged 25-29 years [adjusted odds ratio (OR): 2.48, 95% confidence interval (CI): 1.03-5.96; P=0.042]. Furthermore, high male BMI (adjusted OR: 1.56, 95% CI: 1.14-2.14; P=0.005) and low semen volume (adjusted OR: 2.09, 95% CI: 1.06-4.11; P=0.034) were associated with increased risk of chromosomal aberration-related miscarriages. These findings demonstrate that very young paternal age, high BMI, and low semen volume are associated with increased risk of chromosomal aberration-related miscarriages in couples undergoing ART treatment.

Advanced paternal age does not affect embryo aneuploidy following blastocyst biopsy in egg donor cycles

PURPOSE

To study the impact of advanced paternal age on embryo aneuploidy.

METHODS

This is a multicenter international retrospective case series of couples undergoing assisted reproduction via in vitro fertilization using donor eggs to control for maternal factors and preimplantation genetic testing for aneuploidy via next-generation sequencing at Igenomix reproductive testing centers. The main outcome measure was the prevalence of embryo aneuploidy in egg donor cycles. Semen analysis data was retrieved for a small subset of the male patients.

RESULTS

Data from 1202 IVF/ICSI egg donor cycles using ejaculated sperm (total 6934 embryos) evaluated using PGT-A between January 2016 and April 2018 in a global population across all Igenomix centers were included. No significant association was identified between advancing paternal age and the prevalence of embryo aneuploidy overall and when analyzing for each chromosome. There was also no significant association between advancing paternal age and specific aneuploid conditions (monosomy, trisomy, partial deletion/duplication) for all chromosomes in the genome.

CONCLUSIONS

This is the largest study of its kind in an international patient population to evaluate the impact of advancing paternal age on embryo aneuploidy. We conclude there is no specific effect of paternal age on the prevalence of embryo aneuploidy in the context of embryo biopsies from egg donor cycles.

Decrease in semen quality and Leydig cell function in infertile men: a longitudinal study

STUDY QUESTION

Are infertile men with reduced semen quality at risk of a further decrease in testicular function?

SUMMARY ANSWER

Infertile men with severely reduced semen quality risk further deterioration of semen quality 15 years after treatment for infertility, and a lower baseline sperm concentration was associated with a more pronounced increase in LH and decrease in testosterone/LH ratio at follow-up.

WHAT IS KNOWN ALREADY

Male factors account for up to 50% of human infertility. The most common finding is spermatogenic failure (SgF) yet the life course of semen quality and testosterone production in such men has not been described.

STUDY DESIGN, SIZE, DURATION

A follow-up study of men with SgF was performed 15 years after the initial infertility assessment between January 1995 and December 2000.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Hospital records were used to identify potential participants in the study. A total of 137 men with primary male infertility due to SgF and 70 controls with good semen quality from couples with female factor infertility who attended a tertiary referral centre were included: the participation rate was 31% and 26%, respectively. The men provided semen samples and underwent a physical examination. Blood samples were taken to measure levels of reproductive hormones (FSH, LH, testosterone, sex hormone-binding globulin, estradiol and inhibin B). Current results were compared with results from the initial assessments.

MAIN RESULTS AND THE ROLE OF CHANCE

At the time of follow up the SgF men had significantly lower Leydig cell capacity than the control group as well as much lower semen quality. For the SgF men, between baseline sampling and follow up, the median sperm concentration decreased from 1.9 to 0.6 mill/ml and total sperm count from 7.7 to 2.0 million (P = 0.019 and 0.012, respectively), and 10% developed azoospermia. Calculated free testosterone (cFT), but not total testosterone (tT) decreased in the SgF group by ~0.6% (95% CI 0.1-1.2%) per year. In the SgF group, LH increased by 1.6% (CI 0.9-2.3%) annually, and consequently tT/LH and cFT/LH ratios had decreased by 1.3% (CI 0.5-2.1) and 2.1% (CI 1.2-3.0%), respectively. The increase in LH and the decreases in tT/LH and cFT/LH ratios were more pronounced in men with lower baseline sperm concentrations.

LIMITATIONS, REASONS FOR CAUTION

We consider the case group as representative of infertile men not in need of testosterone treatment at baseline investigation, but do not have information on those that chose not to participate in the follow-up study. There were alterations in some hormone analysis methods during the follow-up period that may introduce uncertainty in interpretation of long-term changes in hormone levels despite rigorous quality control. The validity of the control group suffers from a lack of hormone values at baseline. Also, at follow-up, for practical reasons only one semen sample could be obtained, which makes the effect estimate more uncertain and there is a risk of non-differential misclassification.

WIDER IMPLICATIONS OF THE FINDINGS

Without being able to predict individual outcomes, it is prudent to consider sperm cryopreservation or advise not to postpone fertility treatment when men present with infertility due to impaired semen quality. Whether partly compensated Leydig cell insufficiency in men with SgF will eventually develop into overt testosterone deficiency cannot be determined from our study.

STUDY FUNDING/COMPETING INTEREST(s)

Aase and Einar Danielsen (Grant no. 10-001053), Nordic Research Committee (Grant no. 5109), The Kirsten and Freddie Johansen Fund, and Rigshospitalet's Research Fund (grant no. R24-A812). There are no competing interests.

Impact of advanced paternal age on the intracytoplasmic sperm injection (ICSI) outcomes in donor egg cycles

Background

The purpose of this study is to assess the impact of paternal age on the oocyte-donation outcomes in intracytoplasmic sperm injection (ICSI) cycles.

Methods

Two hundred and seventy-eight infertile couples were retrospectively involved. Inclusion criteria were: infertility from almost 1 year, normal or sub-fertile seminal parameters, overall oocyte survival rate greater than 85%. Baseline characteristics included male age, recipient age, male body mass index (BMI), smoking, drinking status. Main outcome measures: fertilization rate (FR), cleavage rate (CR), pregnancy rate (PR).

Results

Patients were categorized in group 1 ≤45, group 2 >45 years. A total of 1,724 frozen oocytes were included. After warming, 1,642 oocytes survived. Median overall oocyte survival rate was 100% [interquartile range (IQR), 85-100%]. Median male age was 44±5.60 years (IQR, 31-70 years). Median recipients age was 42±3.62 years (IQR, 29-50 years). Group 1 included 166 men, group 2 112 men. Two hundred and seventy-eight fresh ICSI cycle were performed. "Two-pronuclear" (2PN) FR was 72.6%±0.20%, CR 93.0%±0.16%, PR 39.6%. Miscarriage rate was 25.5%. Live birth rate per cycles was 29.5%. Comparison between group 1, group 2 and ICSI outcomes confirmed an association with FR, resulting 80.0% (IQR, 67.0-83.0%) and 67.0% (IQR, 50.0-80.0%), respectively (P<0.01). There were no significant differences between the two groups with respect to seminal parameters.

Conclusions

It would be recommended more emphasis on the advancing male age when counselling older couples who undergo egg donation program.

Lifestyle and fertility: the influence of stress and quality of life on male fertility

BACKGROUND

Male infertility is a widespread condition among couples. In about 50% of cases, couple infertility is attributable to the male partner, mainly due to a failure in spermatogenesis. In recent times, the crucial role that modifiable lifestyle factors play in the development of infertility have generated a growing interest in this field of study, i.e. aging, psychological stress, nutrition, physical activity, caffeine, high scrotal temperature, hot water, mobile telephone use. Several studies have investigated associations between semen quality and the presence of lifestyle stressors i.e. occupational, life events (war, earthquake, etc.) or couple infertility; overall, these studies provide evidence that semen quality is impaired by psychological stress. In this review, we will discuss the impact of quality of life (modifiable lifestyle factors) and psychological stress on male fertility. In addition, the role that increased scrotal temperature along with inappropriate nutritional and physical exercise attitudes exert on male fertility will be presented.

CONCLUSION

The decline of male fertility, particularly associated with advancing age, incorrect lifestyles and environmental factors plays an important role on natality, and its consequences on the future on human population makes this an important public health issue in this century. Thus, modification of lifestyle through a structured program of educational, environmental, nutritional/physical exercise and psychological support, combined with the use of nutraceutical antioxidants can prevent infertility and therefore, may help couples to obtain better quality of life and improved possibility to conceive spontaneously or optimize their chances of conception.

JG. The effects of male age on sperm DNA damage: an evaluation of 2,178 semen samples

OBJECTIVE

This study aimed to evaluate the effects of male age on sperm DNA damage.

METHODS

This cross-sectional study included semen samples collected from 2,178 men seen at an infertility clinic. For DNA integrity analysis, the proportions of spermatozoa showing DNA fragmentation (TUNEL assay), abnormal chromatin packaging/underprotamination (chromomycin A3), abnormal mitochondrial membrane potential (MMP/MitoTracker Green), and apoptosis (annexin V) were recorded. For group comparisons, enrolled subjects were divided into three groups based on their ages: ≤35 years; 36-44 years; and ≥45 years. The associations between age and sperm parameters were assessed using Spearman's rank correlation coefficient.

RESULTS

Although aging did not affect sperm apoptosis (p>.05), sperm DNA fragmentation and MMP deteriorated significantly with age (p<.05). Chromatin packaging/protamination improved significantly with age (p<.05).

CONCLUSION

Sperm DNA fragmentation worsened with age and was apparently associated with mitochondrial damage. The age-related increase in sperm DNA damage suggests that delaying childbearing, not only in women but also in men, might jeopardize a couple's reproductive capacity. The increase seen in chromatin packaging might represent a protective feature for DNA. However, additional studies must be performed to confirm the results concerning chromatin packaging/protamination.

Effect of senescence on some apoptosis and oxidative stress markers in infertile normozospermic and oligospermic men: A cross-sectional study

BACKGROUND

Male senescence may affect testicular function, sperm indices and generation of high levels of oxidants and apoptosis.

OBJECTIVE

This study evaluates the effect of male age on the expression of some apoptosis and oxidative stress markers in seminal fluid of males investigated for infertility in a tertiary health institution in Nigeria.

MATERIALS AND METHODS

In this cross-sectional study, 122 men aged 20-60 yr who were investigated for infertility and were stratified according to age into four groups. Seminal plasma caspase 3, cytochrome C, and total antioxidant capacity (TAC) were assayed by ELISA technique, while manual semen analysis was performed according to WHO standard.

RESULTS

Seminal caspase 3, and cytochrome C activity increased while TAC and sperm indices decreased with increasing age. Cytochrome C (r=0.288; p=0.002) and caspase 3 (r=0.250; p=0.05) correlated significantly with age in normospermia while cytochrome C (r=0.314; p=0.02), caspase 3 (r=0.268; p=0.05), TAC (r=-0.342; p=0.01) and morphology percentage (r=-0.414; p=0.002) correlated with age in oligospermic infertile males.

CONCLUSION

The measured apoptotic markers increased with increasing age while TAC and sperm indices decreased with increasing age of subjects evaluated. Although the levels of measured apoptosis and oxidative stress markers correlated with age in normozospermia, the effect on sperm indices was severe among oligospermia compare to normozospermia. Therefore, these markers may be assayed in aged men attending fertility clinics.

Temporal trends in sperm count: a systematic review and meta-regression analysis

BACKGROUND

Reported declines in sperm counts remain controversial today and recent trends are unknown. A definitive meta-analysis is critical given the predictive value of sperm count for fertility, morbidity and mortality.

OBJECTIVE AND RATIONALE

To provide a systematic review and meta-regression analysis of recent trends in sperm counts as measured by sperm concentration (SC) and total sperm count (TSC), and their modification by fertility and geographic group.

SEARCH METHODS

PubMed/MEDLINE and EMBASE were searched for English language studies of human SC published in 1981-2013. Following a predefined protocol 7518 abstracts were screened and 2510 full articles reporting primary data on SC were reviewed. A total of 244 estimates of SC and TSC from 185 studies of 42 935 men who provided semen samples in 1973-2011 were extracted for meta-regression analysis, as well as information on years of sample collection and covariates [fertility group ('Unselected by fertility' versus 'Fertile'), geographic group ('Western', including North America, Europe Australia and New Zealand versus 'Other', including South America, Asia and Africa), age, ejaculation abstinence time, semen collection method, method of measuring SC and semen volume, exclusion criteria and indicators of completeness of covariate data]. The slopes of SC and TSC were estimated as functions of sample collection year using both simple linear regression and weighted meta-regression models and the latter were adjusted for pre-determined covariates and modification by fertility and geographic group. Assumptions were examined using multiple sensitivity analyses and nonlinear models.

OUTCOMES

SC declined significantly between 1973 and 2011 (slope in unadjusted simple regression models -0.70 million/ml/year; 95% CI: -0.72 to -0.69; P < 0.001; slope in adjusted meta-regression models = -0.64; -1.06 to -0.22; P = 0.003). The slopes in the meta-regression model were modified by fertility (P for interaction = 0.064) and geographic group (P for interaction = 0.027). There was a significant decline in SC between 1973 and 2011 among Unselected Western (-1.38; -2.02 to -0.74; P < 0.001) and among Fertile Western (-0.68; -1.31 to -0.05; P = 0.033), while no significant trends were seen among Unselected Other and Fertile Other. Among Unselected Western studies, the mean SC declined, on average, 1.4% per year with an overall decline of 52.4% between 1973 and 2011. Trends for TSC and SC were similar, with a steep decline among Unselected Western (-5.33 million/year, -7.56 to -3.11; P < 0.001), corresponding to an average decline in mean TSC of 1.6% per year and overall decline of 59.3%. Results changed minimally in multiple sensitivity analyses, and there was no statistical support for the use of a nonlinear model. In a model restricted to data post-1995, the slope both for SC and TSC among Unselected Western was similar to that for the entire period (-2.06 million/ml, -3.38 to -0.74; P = 0.004 and -8.12 million, -13.73 to -2.51, P = 0.006, respectively).

WIDER IMPLICATIONS

This comprehensive meta-regression analysis reports a significant decline in sperm counts (as measured by SC and TSC) between 1973 and 2011, driven by a 50-60% decline among men unselected by fertility from North America, Europe, Australia and New Zealand. Because of the significant public health implications of these results, research on the causes of this continuing decline is urgently needed.

Ginsenoside Rg1 ameliorates testicular senescence changes in D‑gal‑induced aging mice via anti‑inflammatory and antioxidative mechanisms

With the growing population, aging, extended lifespans and anti-aging have become popular areas of research in the life and social sciences. With increasing age, the structure and function of the testes, the spermatogenetic and androgen-producing organ in the male reproductive system, gradually declines. Ginsenoside Rg1 is an extract of Panax ginseng in traditional Chinese medicine. The extract facilitates anti-aging through its anti-inflammatory and antioxidant properties. However, it has not been reported whether ginsenoside Rg1 delays testicular aging. The present study established D-galactose (D-gal)-induced aging mouse models to examine the protective effects of ginsenoside Rg1 on the structure and function of the testes, and the underlying mechanism. A total of 60 healthy specific pathogen-free male C57BL/6 mice were randomly divided into four groups: Control group; Rg1 group; D-gal + Rg1 group; and D-gal group. The tissues of the mice were used for further experiments. The present study further investigated the effects of Rg1 on the volume of serum testosterone, the testicular index, testicular microscopic structures, the senescence of spermatogenetic cells, the apoptosis of spermatogenetic cells, the activity of the antioxidant enzymes, the levels of inflammatory cytokines, and the levels of S-phase kinase-associated protein (p19), cyclin-dependent kinase inhibitor 1 (p21) and cellular tumor antigen p53 (p53) in D-gal-induced aging mice. In general, compared with the D-gal group, the treatment of Rg1 increased the testis index, serum testosterone level and the active content of superoxide dismutase and the total antioxidant capacity. The percentage of senescence-associated β-galactosidase-positive cells, the level of apoptosis and the volume of methane dicarboxylic aldehyde, tumor necrosis factor-α, interleukin (IL)-1β and IL-6 in testicular tissues were significantly decreased, and the expression of p19, p53 and p21 was downregulated due to the treatment with Rg1. The results of the present study demonstrated that ginsenoside Rg1 was able to protect the testes against D-gal-induced aging in mice. In addition, the protective effect of Rg1 may be achieved via antioxidation and downregulation of the p19/p53/p21 signaling pathway.

Resveratrol changes spermatogonial stem cells (SSCs) activity and ameliorates their loss in busulfan-induced infertile mouse

The decline of quantity and quality of sperm are correlated with the increasing age and some anti-cancer compounds such as busulfan. Previous studies have shown that Resveratrol (Res) inhibits tumorigenesis and metastasis of many cancers including mammary tumor, prostate and pancreatic cancers. It acts as anti-age in mouse and human, however, little is known about its protective effect on aged spermatogonial stem cells (SSCs). Here, we investigated the effects of Res in vitro on SSCs using C18-4 cells and in vivo in busulfan-induced azoospermia mice model. The results showed that Res at different concentrations had different effects on C18-4 cells. Treatment with 2 μM of Res promotes cell proliferation and inhibits apoptosis, but stimulates apoptosis with a higher concentration (20 μM) in C18-4 cells. Using busulfan-induced infertility mice model, we demonstrated that Res (30 mg/kg/d and 100 mg/kg/d) clearly ameliorated SSC loss to recover the spermatogenesis. Taken together, our data suggest that Res might be an approach for therapeutic intervention to promote SSC proliferation and cease SSC loss in azoospermia mice model induced by busulfan.

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

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

The correlation of sperm morphology with unexplained recurrent spontaneous abortion: A systematic review and meta-analysis

Sperm morphology displays a potential impact on sperm function and may ultimately impact reproductive function. Current studies have investigated the correlation between sperm morphology with unexplained recurrent spontaneous abortion (RSA) but have shown inconsistent results. Hence, we systematically searched MEDLINE, EMBASE, CNKI databases, as well as the Cochrane Library for studies that examined the association between sperm morphology and unexplained RSA. Fifteen studies were identified, including 883 cases and 530 controls. Our meta-analysis results indicated that the percentage of normal sperm morphology from men with RSA partners was significantly lower than those from normal controls(SMD [95% CI]: - 0.60 [-0.81, -0.40]; P<0.00001) and the percentage of sperm morphologic alterations was significantly higher in patients with RSA compared with the control group (SMD [95% CI]: 0.92 [0.42, 1.43]; P=0.0004). The present study suggested that the percentage of normal sperm morphology may indeed decrease in men from RSA group compared with controls. However, there were some limitations in the study such as the differences in stain techniques and classification criteria. Further evidences are needed to better elucidate the relationship between sperm morphology and unexplained RSA.

The impact of male age on embryo quality: a retrospective study using time-lapse imaging

OBJECTIVE

This study aimed to correlate male age with embryo morphokinetic parameters on D3 considering the timing and the exact moment of embryo cleavage.

METHODS

Time-lapse imaging was used to produce an ideal cleavage curve for the embryos analyzed. The percentage of embryos under the curve was analyzed and correlated with male age.

RESULTS

32.6% of the embryos from patients aged 28-33 years were under the curve; 36.2% of the embryos from patients aged 34-39 years were under the curve; 41.3% of the embryos from patients aged 40-45 years were under the curve; and 26.3% of the embryos fro patients aged 46-57 years were under the curve.

CONCLUSIONS

a statistically non-significant decrease was observed in the percentage of embryos under the optimal cleavage curve on D3 in the group of men aged between 40 and 45 years. Further studies looking into embryos in the blastocyst stage (D5 or D6) are required.