Age thresholds for changes in semen parameters in men

Age related semen parameters and ICSI pregnancy outcomes of 8046 men in Turkey over a 9-year period

The effect of paternal age on fertility remains unclear. This retrospective study aims to examine the impact of male age on semen parameters and the reproductive outcomes of men admitted to an infertility center over a 9-year period. A total of 8046 patients were included in the study. Men were divided into four age groups. The groups were evaluated for semen parameters and reproductive outcome. The 21-30 year group presented lower sperm concentrations in comparison to those aged 31-40 and 41-50, yet shared a similar concentration to those over 50 years of age. Moreover, grades A and B decreased significantly in men aged over 50 years. The highest progressive motility and normozoospermia were observed in the age group 31-40 years while men over 50 years of age had the highest rates of asthenozoospermia and oligoasthenozoospermia. Furthermore, live birth results were reported in 5583 of the patients who underwent intracytoplasmic sperm injection (ICSI) and were found highest between 31-40 years of age. To our knowledge, this is the largest study in Turkey focusing on male age-related semen parameters and ICSI pregnancy outcomes. The study demonstrates that age is a significant factor for semen quality and live birth.

Effect of paternal age on clinical outcomes of in vitro fertilization-embryo transfer cycles

Purpose

This study aimed to investigate the impact of paternal age > 40 years on clinical pregnancy and perinatal outcomes among patients undergoing in vitro fertilization treatment.

Methods

We selected 75 male patients (aged > 40 years) based on predefined inclusion and exclusion criteria. Propensity score matching was performed in a 1:3 ratio, resulting in a control group (aged ≤ 40 years) of 225 individuals. Various statistical tests, including the Mann-Whitney U test, Chi-square test, Fisher's exact test, and binary logistic regression, were used to analyze the association between paternal age and clinical outcomes.

Results

We found no statistically significant differences in semen routine parameters, clinical pregnancy outcomes, and perinatal outcomes between paternal aged > 40 and ≤ 40 years. However, in the subgroup analysis, the live birth rate significantly decreased in those aged ≥ 45 compared to those aged 41-42 and 43-44 years (31.25% vs. 69.23% and 65%, respectively; all p < 0.05). Additionally, the clinical pregnancy rate was significantly lower among those aged ≥ 45 than among those aged 41-42 (43.75% vs. 74.36%; p=0.035).

Conclusion

Paternal age ≥ 45 years was associated with lower live birth and clinical pregnancy rates.

Secondary azoospermia after a successful natural pregnancy: a primary prospective study

BACKGROUND

To date, there is a lack of studies conducted on males with secondary azoospermia as a potential cause of male infertility who had previously fathered children through natural conception. The current study aims to investigate the potential causes of secondary azoospermia as a presentation of male infertility as well as the prognostic factors that can impact sperm retrieval rate (SRR) while undergoing microdissection testicular sperm extraction (microTESE).

RESULTS

Thirty two patients were recruited from the andrology outpatient clinic from August 2023 till January 2024. The mean age of the patients was sixty-two years old. All patients had varicoceles. Twenty seven patients (84%) had palpable varicocele grade 2 and 3 on both sides. Further multivariate logistic regression analysis of the significant factors in the univariate regression revealed that younger age (OR 0.7, 95% C.I. 0.7-1.0, p = 0.03) and having a history of coronary artery disease (CAD) were predictable factors for negative TESE outcome (OR 123.1, 95% C.I. 3.2-4748.5, P = 0.01).

CONCLUSION

It appears that the etiopathogenesis of secondary azoospermia are multifactorial. Varicocele and CAD are major factors to be considered. Future studies should be implemented deploying larger pools of patients suffering from the same condition to affirm the findings of this primary study.

Foal sex in Thoroughbred horses: related factors

Reproductive biotechniques in the equine species have advanced in the last decade and horse breeders have started to question the possibilities of interfering in the determination of foal sex. The aim of the present study was to verify whether the variables mares and stallion's age, side of the ovary containing the preovulatory follicle, preovulatory follicle diameter, time between breeding and ovulation, and ovulation inducing hormones influence the sex of the foal. A total of 259 reproductive cycles of 160 mares and 22 Thoroughbred stallions were used. Statistical analysis was performed using R software, including Pearson's chi-square test and logistic regression. Of the total foals born, 136 were males (52.51%) and 123 were females (47.49%). In mares that ovulated with -24h after ovulation induction, 104 foals (54.74%) were males and 86 (45.26%) were females, while in mares that ovulated with +24h, 32 foals (46.38%) were males and 37 (53.62%) were females. Stallions up to 15 years old had 44.14% (n=49) females and those over 15 years had 49.66% (n=73) females. The simple logistic regression model showed that mares and stallions under 15 years old, mares with ovulation time less than 24 hours and treated with Deslorelin had a higher probability of having male foals, but the Pearson's chi-square test showed that foals gender were not influenced by the variables studied.

The impact of impaired intrauterine growth on male fertility: A systematic review and meta-analysis

BACKGROUND

Adverse intrauterine environment was believed to have deleterious effects on the gonadal function. However, the association between impaired intrauterine growth and fertility in adult males has not been established.

OBJECTIVES

To compare the reproductive rates of males born small for gestational age (SGA), with low birth weight (LBW) or very low birth weight (VLBW) with control groups.

METHODS

The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement was followed to search PubMed, Web of Science, Cochrane Library, and Embase databases from inception to June 16, 2023. Cohort studies investigating the reproductive rates of males born SGA, with LBW or VLBW were included. A random or fixed effects model was used for different exposures.

RESULTS

A total of 10 studies out of 3,801 records were included. Males born SGA showed a higher risk of infertility than the control group (odds ratio, OR = 0.91, 95% confidence interval, 95% CI 0.89-0.93, p = 0.000). The reproductive rates of individuals born with LBW or VLBW were lower than the control group (OR = 0.86, 95% CI 0.78-0.94, p = 0.001; OR = 0.57, 95% CI 0.40-0.81, p = 0.002, respectively). Participants were further divided into two age groups of 18-35 and 35-45 years. In both subgroups, the reproductive rates were lower in males born SGA, with LBW or VLBW compared with controls. Sensitivity analysis showed the robustness of the pooled estimates among LBW and VLBW.

CONCLUSION

In summary, SGA, LBW, and VLBW were associated with a higher risk of male infertility in both early and middle adulthood. Achieving optimal intrauterine growth would be helpful to prevent male infertility.

Association Between Atopic Dermatitis and Aging: Clinical Observations and Underlying Mechanisms

As one of the most prevalent chronic inflammatory skin diseases, atopic dermatitis (AD) increasingly affects the aging population. Amid the ongoing global aging trend, it's essential to recognize the intricate relationship between AD and aging. This paper reviews existing knowledge, summarizing clinical observations of associations between AD and aging-related diseases in various systems, including endocrine, cardiovascular, and neurological. Additionally, it discusses major theories explaining the correlation, encompassing skin-mucosal barriers, systemic inflammation and stress, genes, signal transduction, and environmental and behavioral factors. The association between AD and aging holds significant importance, both in population and basic perspectives. While further research is warranted, this paper aims to inspire deeper exploration of inflammation/allergy-aging dynamics and the timely management of elderly patients with AD.

Advanced Paternal Age in Focus: Unraveling Its Influence on Assisted Reproductive Technology Outcomes

As global demographics shift toward increasing paternal age, the realm of assisted reproductive technologies (ARTs), particularly in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI), faces new challenges and opportunities. This study provides a comprehensive exploration of the implications of advanced paternal age on ART outcomes. Background research highlights the social, cultural, and economic factors driving men toward later fatherhood, with a focus on the impact of delayed paternity on reproductive outcomes. Methods involve a thorough review of existing literature, centering on changes in testicular function, semen quality, and genetic and epigenetic shifts associated with advancing age. Study results point to intricate associations between the father's age and ART outcomes, with older age being linked to diminished semen quality, potential genetic risks, and varied impacts on embryo quality, implantation rates, and birth outcomes. The conclusions drawn from the current study suggest that while advanced paternal age presents certain risks and challenges, understanding and mitigating these through strategies such as sperm cryopreservation, lifestyle modifications, and preimplantation genetic testing can optimize ART outcomes. Future research directions are identified to further comprehend the epigenetic mechanisms and long-term effects of the older father on offspring health. This study underscores the need for a comprehensive approach in navigating the intricacies of delayed fatherhood within the context of ART, aiming for the best possible outcomes for couples and their children.

The Role of One-Carbon Metabolism and Methyl Donors in Medically Assisted Reproduction: A Narrative Review of the Literature

One-carbon (1-C) metabolic deficiency impairs homeostasis, driving disease development, including infertility. It is of importance to summarize the current evidence regarding the clinical utility of 1-C metabolism-related biomolecules and methyl donors, namely, folate, betaine, choline, vitamin B12, homocysteine (Hcy), and zinc, as potential biomarkers, dietary supplements, and culture media supplements in the context of medically assisted reproduction (MAR). A narrative review of the literature was conducted in the PubMed/Medline database. Diet, ageing, and the endocrine milieu of individuals affect both 1-C metabolism and fertility status. In vitro fertilization (IVF) techniques, and culture conditions in particular, have a direct impact on 1-C metabolic activity in gametes and embryos. Critical analysis indicated that zinc supplementation in cryopreservation media may be a promising approach to reducing oxidative damage, while female serum homocysteine levels may be employed as a possible biomarker for predicting IVF outcomes. Nonetheless, the level of evidence is low, and future studies are needed to verify these data. One-carbon metabolism-related processes, including redox defense and epigenetic regulation, may be compromised in IVF-derived embryos. The study of 1-C metabolism may lead the way towards improving MAR efficiency and safety and ensuring the lifelong health of MAR infants.

Using Bayesian and weighted regression to evaluate the association of idiopathic oligoastenoteratozoospermia with seminal plasma metal mixtures

Idiopathic oligoastenoteratozoospermia (iOAT) affects 30% of infertile men of reproductive age. However, the associations between Cr, Fe, Cu, Se or Co levels and iOAT risk have not been determined. This research aimed to assess the associations between Cr, Fe, Cu, Se and Co levels as well as their mixtures in seminal plasma and the risk of iOAT and severe iOAT. Therefore, a case‒control study including 823 participants (416 iOAT patients and 407 controls) recruited from October 2021 to August 2022 at the reproductive medicine center of the First Affiliated Hospital of Anhui Medical University was conducted in Anhui, China. The concentrations of Cr, Fe, Cu, Se and Co in seminal plasma were detected via inductively coupled plasma‒mass spectrometry. Binary logistic regression models were used to assess the associations between the levels of Cr, Fe, Cu, Se and Co and the risk of iOAT and severe iOAT; additionally, Bayesian kernel machine regression (BKMR) and weighted quantile sum (WQS) regressions were performed to evaluate the joint effect of seminal plasma levels of Cr, Fe, Cu, Se and Co on the risk of iOAT and explore which elements contributed most to the relationship. We found significant associations between the concentrations of Fe, Cu and Se in seminal plasma and iOAT risk after adjusting for covariates (Fe, lowest tertile vs. second tertile: aOR = 1.86, 95% CI = 1.31, 2.64; Cu, lowest tertile vs. second tertile: aOR = 1.95, 95% CI = 1.37, 2.76; Se, lowest tertile vs. second tertile: aOR = 1.65, 95% CI = 1.17, 2.35). A lower Se concentration in seminal plasma (lowest tertile vs. second tertile: aOR = 1.84, 95% CI = 1.10, 3.10) was positively associated with the risk of severe iOAT. Additionally, we also observed an association between the concentration of Cr in seminal plasma and the risk of iOAT before adjusting for covariates (Cr, third tertile vs. lowest tertile: OR=1.44, 95% CI: 1.03, 2.02). According to the BKMR analyses, the risk of iOAT increased when the overall concentrations were less than the 25th percentile. The results from the WQS regression indicated that a negative WQS index was significantly associated with the iOAT risk, while a positive WQS index was not. Se and Fe had significant weights in the negative direction. In conclusion, lower Cu, Fe and Se levels in seminal plasma were positively associated with iOAT risk, while higher Cr levels in seminal plasma were positively associated with iOAT risk according to the single element model, and lower levels of Se were related to a greater risk of severe iOAT; when comprehensively considering all the results from BKMR and WQS regression, Fe, Se and Cr levels contributed most to this relationship.

Effects of reactive oxygen species and mitochondrial dysfunction on reproductive aging

Mitochondria, the versatile organelles crucial for cellular and organismal viability, play a pivotal role in meeting the energy requirements of cells through the respiratory chain located in the inner mitochondrial membrane, concomitant with the generation of reactive oxygen species (ROS). A wealth of evidence derived from contemporary investigations on reproductive longevity strongly indicates that the aberrant elevation of ROS level constitutes a fundamental factor in hastening the aging process of reproductive systems which are responsible for transmission of DNA to future generations. Constant changes in redox status, with a pro-oxidant shift mainly through the mitochondrial generation of ROS, are linked to the modulation of physiological and pathological pathways in gametes and reproductive tissues. Furthermore, the quantity and quality of mitochondria essential to capacitation and fertilization are increasingly associated with reproductive aging. The article aims to provide current understanding of the contributions of ROS derived from mitochondrial respiration to the process of reproductive aging. Moreover, understanding the impact of mitochondrial dysfunction on both female and male fertility is conducive to finding therapeutic strategies to slow, prevent or reverse the process of gamete aging, and thereby increase reproductive longevity.

Traditional Chinese Medicine formula Wubi Shanyao Pills protects against reproductive aging by activating SIRT1/3 to reduce apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

The study of male reproductive aging and its associated concerns holds significant importance within the realm of health issues affecting the elderly population. Wubi Shanyao Pills (WSP), a traditional Chinese patent medicine originating from the Tang Dynasty, has been recognized for its ability to enhance male sexual functions while also tonifying the kidney and spleen. Nevertheless, the precise effects and underlying mechanisms through which WSP ameliorates the decline in reproductive function among aging men remain uncertain.

AIM OF THE STUDY

This study elucidated the distinctive impacts of WSP on ameliorating the decline in reproductive function caused by natural aging, as well as its underlying mechanisms.

MATERIALS AND METHODS

Initially, male mice at the age of 15 months were administered WSP orally at doses of 0.375, 0.75, and 1.50 g/kg per day for a duration of 8 consecutive weeks. The impact of WSP on age-related manifestations in naturally aging mice was assessed based on their behavioral performance. The renal function of the mice was evaluated by measuring serum biochemical indicators, including Creatinine (CR), Uric acid (UA), and Blood urea nitrogen (BUN). Additionally, Superoxide dismutase (SOD) and Malonaldehyde (MDA) levels in renal tissue were determined using applied chemistry methods. Then assessed the levels of Nitric oxide (NO), Total nitric oxide synthase (T-NOS), Guanosine cyclase (GC), and Cyclic guanosine monophosphate (cGMP) in the penile tissue, as well as the expression of Endothelial nitric oxide synthase (eNOS) and Guanylate Cyclase Activator (GUCA) protein, in order to investigate the erectile function of the penis. Additionally, the quality of epididymal sperm was examined using an electron microscope. Furthermore, the serum sex hormone level and related protein expression were determined through the utilization of enzyme-linked immunosorbent assay and immunohistochemistry techniques. Pathological alterations and the ultrastructure of the testis were investigated using hematoxylin-eosin staining and transmission electron microscopy. Subsequently, the apoptosis of spermatogenic cells in the testes was assessed employing TUNEL, immunofluorescence, western blotting, and quantitative real-time polymerase chain reaction.

RESULTS

The administration of WSP has been found to enhance the behavioral performance and sexual behavior in aged mice. It's also could increase in serum levels of CR, UA, and BUN, as well as the elevation of SOD activity in kidney tissue, which subsequently leads to a reduction in MDA levels and an improvement in the structural damage caused by aging in the kidney tissue. Consequently, the renal function is enhanced. Additionally, WSP has been observed to elevate the levels of NO, T-NOS, GC, and cGMP in penile tissue, along with an increase in eNOS and GUCA protein expression, indicating an improvement in penile erectile function. The administration of WSP resulted in a decrease in the occurrence of programmed cell death in testicular germ cells, leading to an enhancement in sperm quality and the overall function of testicular spermatogenesis. This improvement can be attributed to the modulation of hormone levels and the regulation of SIRT1/3, p53, FOXO3, Bax, and Caspase-3 expression.

CONCLUSION

Collectively, our findings indicate that the administration of WSP has the potential to impede the occurrence of programmed cell death in testicular cells by modulating the expression of SIRT1/3 and subsequent genes associated with apoptosis. Consequently, this regulatory mechanism facilitates the proliferation of testicular cells and sustains the spermatogenic function of the testes. Consequently, by modulating the levels of sexual hormones in naturally aging mice, WSP ultimately enhances the quality of sperm and reproductive function. Concurrently, it also ameliorates age-related behavioral changes, renal function, and erectile function.

Addition of low concentration of cholesterol-loaded cyclodextrin (CLC) has a positive effect on cryopreserved canine spermatozoa evaluated by andrological and biophysical methods

BACKGROUND

This study was conducted to find the best concentration of cholesterol-loaded cyclodextrin (CLC) which has a positive impact on canine post thaw semen quality. Three different concentrations of CLC (0.83 mg/ml; 1.66 mg/ml; 3.32 mg/ml) and 2-hydroxylpropyl-beta-cyclodextrin (HBCD) (1.66 mg/ml) were used in addition to cryopreservation extender and compared with the control after thawing. Samples were assessed using computer-assisted semen analyzer (CASA), flow cytometry, fluorimeter by measuring the fluorescence anisotropy (ANISO) and determining the generalized membrane polarization (GP).

RESULTS

An addition of 0.83 mg/ml CLC significantly increased the percentage of progressive motile (PROG) and rapid spermatozoa (RAP) (P < 0.05). 1.66 mg/ml HBCD decreased progressive motility of spermatozoa and population with rapid movement relative to the control (P < 0.05). Furthermore, the groups with an addition of 1.66 mg/ml and 3.32 mg/ml of CLC, as well as the group with only cyclodextrin, increased percentage of dead spermatozoa without lipid peroxidation and decreased percentage of viable spermatozoa without LPO which was lower in these groups than in the control (P < 0.05). Other sperm parameters assessed on flow cytometer were not significantly different. The addition of CLC at 0.83 mg/ml and 3.32 mg/ml concentrations and 1.66 mg/ml of HBCD caused an increase in ANISO measured at 23 ºC (P < 0.05).

CONCLUSIONS

In conclusion, the results suggest that increasing cholesterol in the plasma membrane of canine spermatozoa can improve their freezability. However, only low concentrations of CLC may improve semen quality after thawing without adversely affecting other parameters.

KEAP1-NRF2 system regulates age-related spermatogenesis dysfunction

Purpose

The average fatherhood age has been consistently increasing in developed countries. Aging has been identified as a risk factor for male infertility. However, its impact on various mechanisms remains unclear. This study focused on the KEAP1-NRF2 oxidative stress response system, by investigating the relationship between the KEAP1-NRF2 system and age-related changes in spermatogenesis.

Methods

For examination of age-related changes, we used 10-, 30-, 60-, and 90-week-old mice to compare sperm count, sperm motility, and protein expression. For assessment of Keap1 inhibition, 85-week-old C57BL/6J mice were randomly assigned to the following groups: control and bardoxolone methyl (KEAP1 inhibitor). Whole-exome sequencing of a Japanese cohort of patients with non-obstructive azoospermia was performed for evaluating.

Results

Sperm count decreased significantly with aging. Oxidative stress and KEAP1 expression in the testes were elevated. Inhibition of KEAP1 in aging mice significantly increased sperm count compared with that in the control group. In the human study, the frequency of a missense-type SNP (rs181294188) causing changes in NFE2L2 (NRF2) activity was significantly higher in patients with non-obstructive azoospermia than in healthy control group.

Conclusions

The KEAP1-NRF2 system, an oxidative stress response system, is associated with age-related spermatogenesis dysfunction.

The association between levels of samarium, hafnium, tungsten and rhenium in seminal plasma and the risk of idiopathic oligo-astheno-teratozoospermia in men of childbearing age

Oligo-astheno-teratozoospermia (OAT) is a global public health problem, which affects 30% men of childbearing age. Meanwhile, with the rapid development of industry and economy, the contents of rare earth elements (REEs) in the environment are increasing. However, little is known about the associations between REEs levels and OAT risk. To evaluate the associations between the levels of four REEs (samarium (Sm), hafnium (Hf), tungsten (W), rhenium (Re)) in seminal plasma and OAT risk, from October 2021 to November 2022, semen samples from 924 men of childbearing age (460 controls and 464 cases) were collected from the reproductive center of the First Affiliated Hospital of Anhui Medical University. Inductively coupled plasma-mass spectrometry (ICP-MS) was used to measure the levels of Sm, Hf, Re and W in seminal plasma. Bayesian kernel machine regression (BKMR) was conducted to explore the joint effects of levels of four REEs in seminal plasma on the risk of OAT and select the one exerting a major role; generalized linear regression models (GLM) with log link function were employed to investigate the association of every REE level in seminal plasma and OAT risk; sankey diagram and linear regression models were utilized to describe the associations between the levels of four REEs and the indexes of sperm quality. The levels of four REEs in seminal plasma were higher in the case group than levels in the control group (pSm = 0.011, pHf = 0.040, pW = 0.062, pRe = 0.001, respectively). In BKMR analysis, the OAT risk increased when the overall levels of four REEs were higher than their 55th percentile compared to all of them at their 50th percentile, and Re level played a major role in the association. Additionally, Re level in seminal plasma was positively associated with  the OAT risk in the single element model after adjustment of covariates (medium vs. low: OR (95% CI) = 1.55 (1.10, 2.18); high vs. low: OR (95% CI) = 1.69 (1.18, 2.42)). Lastly, the sankey diagram and linear regression models revealed that Sm level was negatively associated with the PR%, total sperm count and total progressively motile sperm count; Hf level was negatively associated with the PR%; W and Re levels were negatively associated with the PR% and total motility, and Re level was positively associated with abnormal morphology rate. Men of childbearing age with OAT had higher levels of Sm, Hf and Re in seminal plasma than those in the control group. An increasing trend for the OAT risk was observed with an increase in mixture levels of Sm, Hf, W and Re, and Re exposure level played a major role in the association whether in BKMR model or single element model. Additionally, the levels of these four REEs were negatively associated with the indexes of sperm quality.

Exposure to particulate matter may affect semen quality via trace metals: Evidence from a retrospective cohort study on fertile males

Particulate matter (PM) exposure may be associated with male semen quality. Besides, PM exposure induces up and down levels of trace metals in tissues or organs. The levels of trace metals in semen are critical for adverse male semen quality. This study aims to evaluate the concentrations of seminal-level trace metals in fertile men and assess its associations with PM exposure and to explore the mediation role of trace metals in seminal plasma plays in the relationship between PM exposure and semen quality. Total 1225 fertile men who participated in a cohort study from 2014 to 2016 were finally recruited. Multivariate linear regression was applied to explore associations between each two of PM exposure, trace metals and semen parameters. 1-year PM2.5 and PM10 exposure levels were positively associated with arsenic (As), mercury (Hg), lanthanum (La), praseodymium (Pr), neodymium (Nd) but negatively associated with vanadium (V), magnesium (Mg), strontium (Sr), barium (Ba) in semen. It was also found that most of the elements were associated with total sperm number, followed by sperm concentration. Redundancy analysis (RDA) also determined several strong positive correlations or negative correlations between 1-year PM exposure and trace metals. Mediation analysis found that trace metals had a potentially compensatory or synergetic indirect effect on the total effect of the association between 1-year PM exposure and semen quality. The retrospective cohort study provides long-term PM exposure that may cause abnormal semen quality by affecting seminal plasma element levels.

Y chromosome microdeletions in Chinese men with infertility: prevalence, phenotypes, and intracytoplasmic sperm injection outcomes

BACKGROUND

The incidence of Y chromosome microdeletions varies among men with infertility across regions and ethnicities worldwide. However, comprehensive epidemiological studies on Y chromosome microdeletions in Chinese men with infertility are lacking. We aimed to investigate Y chromosome microdeletions prevalence among Chinese men with infertility and its correlation with intracytoplasmic sperm injection (ICSI) outcomes.

METHODS

This single-center retrospective study included 4,714 men with infertility who were evaluated at the Reproductive Center of the First Affiliated Hospital of Sun Yat-sen University between May 2017 and January 2021. Semen analysis and Y-chromosome microdeletion via multiplex polymerase chain reaction were conducted on the men. The study compared outcomes of 36 ICSI cycles from couples with male azoospermia factor (AZF)cd deletions with those of a control group, which included 72 ICSI cycles from couples without male Y chromosome microdeletions, during the same period. Both groups underwent ICSI treatment using ejaculated sperm.

RESULTS

Among 4,714 Chinese men with infertility, 3.31% had Y chromosome microdeletions. The combined deletion of sY254 and sY255 in the AZFc region and sY152 in the AZFd region was the prevalent pattern of Y chromosome microdeletion, with 3.05% detection rate. The detection rates of AZF deletions in patients with normal total sperm count, mild oligozoospermia, severe oligozoospermia, cryptozoospermia, and azoospermia were 0.17%, 1.13%, 5.53%, 71.43%, and 7.54%, respectively. Compared with the control group, the AZFcd deletion group exhibited no significant difference in the laboratory results or pregnancy outcomes of ICSI cycles using ejaculated sperm.

CONCLUSIONS

This is the largest epidemiological study on Y chromosome microdeletions in Chinese men with infertility. The study results underline the necessity for detecting Y chromosome microdeletion in men with infertility and severe sperm count abnormalities, especially those with cryptozoospermia. The combined deletion of sY254 and sY255 in the AZFc region and sY152 in the AZFd region was the most prevalent Y chromosome microdeletion pattern. Among patients with AZFcd deletion and ejaculated sperm, ICSI treatment can result in pregnancy outcomes, similar to those without AZFcd deletion.

Impact of increased paternal age on neonatal outcomes in very-low-birth-weight infants

OBJECTIVE

Despite the trend of increasing paternal age, its impact on neonatal outcomes, particularly in preterm infants, has not been thoroughly investigated. We aimed to evaluate the perinatal characteristics and neonatal outcomes associated with paternal age.

METHODS

Electronic medical records of very low-birthweight infants admitted to our unit from July 2013 to March 2022 were reviewed. Infants grouped according to paternal age (<35 years, 35-39 years, and ≥40 years) were analyzed for differences in perinatal findings and neonatal outcomes.

RESULTS

A total of 637 infants were included (194, 294, and 149 in the <35, 35-39, and ≥40 years groups, respectively). The increase in paternal age paralleled the increase in maternal age. The Z-score of head circumference at birth was significantly different between the groups, showing the lowest median value in the ≥40 years group. Small-for-gestational age (Odds ratio 71.074, p < .001, 95% confidence interval 19.337 - 261.236) and male sex (Odds ratio 3.309, p < .034, 95% confidence interval 1.089 - 8.425), but not paternal or maternal age groups were significant factors associated with head circumference Z-scores less than -2 standard deviation based on the multivariable logistic regression analysis. Infants affected by chromosomal or genetic anomaly were more frequently identified (3.4 vs 0.0 vs 0.5%) in the ≥40 years group than in the other two groups. When infants with anomalies or critical illnesses were excluded, overall neonatal outcomes did not statistically differ according to paternal age.

CONCLUSION

Although increased paternal age ≥40 years may be associated with relatively smaller head circumferences, the impact on fetal head growth does not imply a definite risk for microcephaly. Nonetheless, based on the possible negative impact on chromosomal/genetic anomaly, increased paternal age warrants attention, even though neonatal outcomes concerning prematurity were not significantly affected. A large-scale longitudinal study is needed to further elucidate the impact of advanced paternal age in preterm infants and provide guidelines for appropriate antenatal counseling and surveillance.

Epigenetic aging of mammalian gametes

The process of aging refers to physiological changes that occur to an organism as time progresses and involves changes to DNA, proteins, metabolism, cells, and organs. Like the rest of the cells in the body, gametes age, and it is well established that there is a decline in reproductive capabilities in females and males with aging. One of the major pathways known to be involved in aging is epigenetic changes. The epigenome is the multitude of chemical modifications performed on DNA and chromatin that affect the ability of chromatin to be transcribed. In this review, we explore the effects of aging on female and male gametes with a focus on the epigenetic changes that occur in gametes throughout aging. Quality decline in oocytes occurs at a relatively early age. Epigenetic changes constitute an important part of oocyte aging. DNA methylation is reduced with age, along with reduced expression of DNA methyltransferases (DNMTs). Histone deacetylases (HDAC) expression is also reduced, and a loss of heterochromatin marks occurs with age. As a consequence of heterochromatin loss, retrotransposon expression is elevated, and aged oocytes suffer from DNA damage. In sperm, aging affects sperm number, motility and fecundity, and epigenetic changes may constitute a part of this process. 5 methyl-cytosine (5mC) methylation is elevated in sperm from aged men, but methylation on Long interspersed nuclear elements (LINE) elements is reduced. Di and trimethylation of histone 3 lysine 9 (H3K9me2/3) is reduced in sperm from aged men and trimethylation of histone 3 lysine 27 (H3K27me3) is elevated. The protamine makeup of sperm from aged men is also changed, with reduced protamine expression and a misbalanced ratio between protamine proteins protamine P1 and protamine P2. The study of epigenetic reproductive aging is recently gaining interest. The current status of the field suggests that many aspects of gamete epigenetic aging are still open for investigation. The clinical applications of these investigations have far-reaching consequences for fertility and sociological human behavior.

Age-Related COVID-19 Influence on Male Fertility

The impact of coronavirus on the reproductive health of men attracts the special attention of many researchers. While studies suggest changes in sperm parameters and the possibility of testicular inflammation, further studies are needed to elucidate any potential age-related changes in these findings, which is the purpose of the present study. The semen quality parameters, cytokine concentration, and markers of the pro- and antioxidant system were assessed in 60 men five to seven months after the coronavirus infection and in 77 controls (without a history of coronavirus infection). Additionally, participants were divided into two age groups: less than 35 years and 35 years or older. Notably increased round cell count in ejaculate and reduced sperm hyaluronan binding ability were observed among post-infection patients younger than 35 years. In the same group, a decline in seminal plasma zinc levels and nitrotyrosine in the cell fraction was found. In men over 35 years of age, Coronavirus Disease 2019 (COVID-19) led to increased sperm DNA fragmentation, a decrease in the total antioxidant capacity, and an elevation in the levels of interleukin-1β and interleukin-10. The concentration of interleukin-1β decreased over time following recovery in all affected patients. The data obtained suggest the potential adverse impact of the coronavirus infection on male reproductive health; however, these effects appear to be age-dependent.

Age-Dependent Alterations in Semen Parameters and Human Sperm MicroRNA Profile

The trend to delay parenthood is increasing, impacting fertility and reproductive outcomes. Advanced paternal age (APA), defined as men's age above 40 years at conception, has been linked with testicular impairment, abnormal semen parameters, and poor reproductive and birth outcomes. Recently, the significance of sperm microRNA for fertilization and embryonic development has emerged. This work aimed to investigate the effects of men's age on semen parameters and sperm microRNA profiles. The ejaculates of 333 Portuguese men were collected between 2018 and 2022, analyzed according to WHO guidelines, and a density gradient sperm selection was performed. For microRNA expression analysis, 16 normozoospermic human sperm samples were selected and divided into four age groups: ≤30, 31-35, 36-40, and >40 years. microRNA target genes were retrieved from the miRDB and TargetScan databases and Gene Ontology analysis was performed using the DAVID tool. No significant correlation was found between male age and conventional semen parameters, except for volume. Fifteen differentially expressed microRNAs (DEMs) between groups were identified. Enrichment analysis suggested the involvement of DEMs in the sperm of men with advanced age in critical biological processes like embryonic development, morphogenesis, and male gonad development. Targets of DEMs were involved in signaling pathways previously associated with the ageing process, including cellular senescence, autophagy, insulin, and mTOR pathways. These results suggest that although conventional semen parameters were not affected by men's age, alterations in microRNA regulation may occur and be responsible for poor fertility and reproductive outcomes associated with APA.

Seminal Calbindin 2 in Infertile Men With Varicocele: A Prospective Comparative Study

The present study compared seminal calbindin 2 (CALB 2) levels and semen parameters in men with and without varicocele. CALB 2 is also known as calretinin and 29 kDa calbindin. The study was a case-control study conducted from April (2021) to March (2022) in the andrology department at Beni-Suef University hospital. The study included four matched groups: group (I) were controls (fertile normozoospermic men without varicocele) (n=24). Group (II) were fertile normozoospermic men with varicocele (n=24). Group (III) were infertile oligoasthenoteratozoospermia (OAT) men without varicocele (n=24). Group (IV) were infertile OAT men with varicocele (n=24). The lowest levels of seminal CALB 2 were found in patients with severe oligozoospermia which showed a statistically significant difference when compared to seminal CALB 2 in patients with normal, mildly low, or moderately low sperm counts. There were significant negative correlations between sperm concentration, sperm motility and percentage of normal sperm forms and seminal CALB 2. Seminal plasma CALB 2 may play a role in the negative impact of varicocele on the semen parameters especially sperm concentration, sperm motility and percentage of sperm normal forms. Future studies are needed to verify these findings.

Impact of male age on paternal aneuploidy: single-nucleotide polymorphism microarray outcomes following blastocyst biopsy

RESEARCH QUESTION

Does advanced paternal age (APA; ≥40 years) contribute to a higher incidence of paternal origin aneuploidy in preimplantation embryos?

DESIGN

This was a multicentre retrospective study of single-nucleotide polymorphism (SNP) microarray (Natera and Karyomapping) preimplantation genetic testing (PGT) outcomes of blastocyst-stage embryos. Whole-chromosome aneuploidy analysis was performed on 2409 embryos from 389 male patients undertaking 681 assisted reproductive technology (ART) cycles between 2012-2021. Segmental aneuploidy analysis was performed on 867 embryos from 140 men undertaking 242 ART cycles between 2016-2021. Embryos were grouped based on paternal age at sperm collection: <35, 35-39 and ≥40 years. Paternal and maternal origin aneuploidy rates were compared between groups using chi-squared and/or Fisher's exact tests.

RESULTS

There was no significant difference across groups in paternal origin whole-chromosome aneuploidy rate, overall (P=0.7561) or when segregated by type (trisomy and monosomy: P=0.2235 and 0.8156) or complexity (single versus 2, 3 or ≥4 aneuploidies: P=0.9733, 0.7517, 0.669 and 0.1481). Conversely, maternal origin whole-chromosome aneuploidy rate differed across groups (P<0.0001) in alignment with differing mean maternal age (P<0.001). Paternal origin deletions were 2.9-fold higher than maternal origin deletions (P=0.0084), independent of age stratification. No significant difference in paternal origin deletions was observed with APA ≥40 compared with the younger age groups (4.8% versus 2.5% and 2.8%, P=0.5292). Individual chromosome aneuploidy rates were too low to perform statistical comparisons.

CONCLUSIONS

No significant association was found between APA and the incidence of paternal origin aneuploidy in preimplantation embryos, irrespective of type or complexity. Thus, APA may not be an indication for PGT.

Impact of paternal age on assisted reproductive technology outcomes and offspring health: a systematic review

BACKGROUND

The increase in paternal age and the percentage of births after assisted reproductive technologies (ART) may have consequences on offspring and society's position regarding access to ART must be questioned. Most countries recommend limiting ART to men under 60 years. What is the rationale for this threshold?

OBJECTIVE

This systematic review assesses scientific arguments to establish links between paternal age, male fertility, and offspring health.

MATERIAL AND METHODS

Using the PRISMA guidelines, this systematic review of the literature analyzed 111 articles selected after screening PubMed, ScienceDirect, and Web of Science for articles published between January 1, 1995 and December 31, 2021.

RESULTS

A strong correlation was highlighted between advanced paternal age and a decrease of some sperm parameters (semen volume and sperm motility) and infant morbidity (exponentially increased incidence of achondroplasia and Apert syndrome, and more moderately increased incidence of autism and schizophrenia). The impact of paternal age on pregnancy and fetal aneuploidy rates is more controversial. No association was found with spontaneous abortion rates.

DISCUSSION AND CONCLUSION

The scientific parameters should be explained to older parents undergoing ART. And for countries that discuss a limit on paternal age for access to ART, the debate requires consideration of social and ethical arguments.

Global trends in semen quality of young men: a systematic review and regression analysis

PURPOSE

Many studies have reported declines in semen quality mainly focused on total sperm counts (TSC) and sperm concentration (SC), ignoring the importance of progressive motile sperm (PR), total motile sperm (TM), and normal morphological sperm (NM). Therefore, we performed a comprehensive meta-analysis to explore the trend in semen quality of young men.

METHODS

We searched 3 English databases and 4 Chinese databases from January 1980 to August 2022. Random-effect meta-analyses and weighted linear regression models were conducted to perform the trend in semen quality.

RESULTS

Finally, 162 eligible studies including 264,665 men from 28 countries were got between 1978 and 2021. Significant decreases were observed in TSC (- 3.06 million/year, 95% CI - 3.28 to - 2.84), SC (- 0.47 million/ml/year, 95% CI - 0.51 to - 0.43), and PR (- 0.15%/year, 95% CI - 0.20 to - 0.09), and there was an upward trend in TM (0.28%/year, 95% CI 0.24 to 0.32). The results of meta-regression analyses indicated that age, continent, income, WHO criteria, and abstinence time significantly impacted on TSC, SC, PR, and TM. Positive regression coefficients were observed in some categories suggesting that outcomes might not be declining and even increasing in these subgroups.

CONCLUSIONS

Downward trends in semen quality among global young men were observed in our study, including TSC, SC, and PR. But TM did not appear to be trending down or even to be leveling off. More studies are needed to focus on the causes of the declines.

Effects of melatonin on a d-galactose-induced male reproductive aging mouse model

Understanding the aging mechanism of the male reproductive system and developing anti-aging interventions are essential for preventing age-related male infertility. The pineal hormone melatonin has been effectively used as an antioxidant and anti-apoptotic molecule in various cells and tissues. However, the effects of melatonin on d-galactose (D-gal)-induced aging have not been studied with regards to testicular function. Thus, we investigated whether melatonin suppresses the dysfunction of male reproductive function induced by D-gal treatment. The mice were divided into the following four groups receiving treatments for six weeks: phosphate-buffered saline (PBS) group, d-galactose (200 mg/kg) group, melatonin (20 mg/kg) group, and d-galactose (200 mg/kg)+ melatonin (20 mg/kg) group. At six weeks of treatments, sperm parameters, body and testes weight, gene and protein expression of germ cell and spermatozoa marker were analyzed. Our results showed that melatonin suppressed the decrease in body weight, sperm vitality, motility, and gene expression levels of spermatozoa markers such as Protamine 1, PGK2, Camk4, TP1, and Crem in the testis of D-gal-induced aging models. However, the gene expression levels of the pre-meiotic and meiotic markers in the testes did not change in the D-gal-injected model. The injection of D-gal impaired the decreased expression of steroidogenic enzyme genes, such as HSD3b1, Cyp17a1, and Cyp11a1, but melatonin inhibited the decrease in the expression of these genes. In addition, protein levels of spermatozoa and germ cell markers were evaluated by immunostaining and immunoblotting. Consistent with the qPCR results, PGK2 protein levels were decreased by d-galactose treatment. A decrease in PGK2 protein levels by D-gal was inhibited by melatonin treatment. In conclusion, melatonin administration improves testicular function with age.

Trends in sperm quality by computer-assisted sperm analysis of 49,189 men during 2015-2021 in a fertility center from China

Background

Sperm quality, including semen volume, sperm count, concentration, and total and progressive motility (collectively, "semen parameters"), has declined in the recent decades. Computer-assisted sperm analysis (CASA) provides sperm kinematic parameters, and the temporal trends of which remain unclear. Our objective is to examine the temporal trend of both semen parameters and kinematic parameters in Shanghai, China, in the recent years.

Methods

This retrospective study analyzed semen parameters and kinematic parameters of 49,819 men attending our reproductive center by using CASA during 2015-2021. The total sample was divided into two groups: samples that surpassed the WHO guideline (2010) low reference limits ("above reference limit" group, ARL; n = 24,575) and samples that did not ("below reference limit" group, BRL; n = 24,614). One-way analysis of variance, Kruskal-Wallis test, independent samples t-test, and covariance analysis were used to assess the differences among groups. Year, age, and abstinence time were included in the multiple linear regression model of the ARL group to adjust the confounders and depict the trends in sperm quality.

Results

Among all the total sample and the ARL and BRL groups, the age of subjects increased in recent years. Semen volume and sperm count showed declined tendency with years in the total sample, the ARL and BRL groups, and the subgroup of age or abstinence time, whereas sperm velocities showed increased tendency with years on the contrary. The multiple linear regression model of the ARL group, adjusting for age and abstinence time, confirmed these trends. Semen volume (β1= -0.162; CI: -0.172, -0.152), sperm count (β1= -9.97; CI: -10.813, -9.128), sperm concentration (β1 = -0.535; CI: -0.772, -0.299), motility (β1 = -1.751; CI: -1.830, -1.672), and progressive motility (β1 = -1.12; CI: -0.201, -0.145) decreased with year, whereas curvilinear line velocity (VCL) (β1 = 3.058; CI: 2.912, 3.203), straight line velocity (VSL) (β1 = 2.075; CI: 1.990, 2.161), and average path velocity (VAP) (β1 = 2.305; CI: 2.224, 2.386) increased over time (all p < 0.001). In addition, VCL, VSL, and VAP significantly declined with age and abstinence time.

Conclusion

The semen parameters declined, whereas the kinematic parameters increased over the recent years. We propose that, although sperm count and motility declined over time, sperm motion velocity increased, suggesting a possible compensatory mechanism of male fertility.

Age-related elevation of O-GlcNAc causes meiotic arrest in male mice

In recent years, the postponement of childbearing has become a critical social issue. Male fertility is negatively associated with age because of testis aging. Spermatogenesis is impaired with age, but the molecular mechanism remains unknown. The dynamic posttranslational modification O-linked N-acetylglucosamine (O-GlcNAc), which is a type of monosaccharide modification, has been shown to drive the process of aging in various systems, but it has not yet been investigated in the testis and male reproductive aging. Thus, this study aims to investigate the alteration of O-GlcNAc with aging and explore the role of O-GlcNAc in spermatogenesis. Here, we demonstrate that the decline in spermatogenesis in aged mice is associated with elevation of O-GlcNAc. O-GlcNAc is specifically localized in differentiating spermatogonia and spermatocytes, indicating its crucial role in meiotic initiation and progression. Mimicking the age-related elevation of O-GlcNAc in young mice by disabling O-GlcNAcase (OGA) using the chemical inhibitor Thiamet-G can recapitulate the impairment of spermatogenesis in aged mice. Mechanistically, the elevation of O-GlcNAc in the testis leads to meiotic pachytene arrest due to defects in synapsis and recombination. Furthermore, decreasing O-GlcNAc in aged testes using an O-GlcNAc transferase (OGT) inhibitor can partially rescue the age-related impairment of spermatogenesis. Our results highlight that O-GlcNAc, as a novel posttranslational modification, participates in meiotic progression and drives the impairment of spermatogenesis during aging.

An Exploratory Analysis of Firefighter Reproduction through Survey Data and Biomonitoring

Firefighters are occupationally exposed to chemicals that may affect fertility. To investigate this effect, firefighters were recruited to contribute blood, urine, breast milk or semen samples to (1) evaluate chemical concentrations and semen parameters against fertility standards and the general population; (2) assess correlations between chemical concentrations and demographics, fire exposure and reproductive history; and (3) consider how occupational exposures may affect reproduction. A total of 774 firefighters completed the online survey, and 97 firefighters produced 125 urine samples, 113 plasma samples, 46 breast milk samples and 23 semen samples. Blood, urine and breast milk samples were analysed for chemical concentrations (semivolatile organic compounds, volatile organic compounds, metals). Semen samples were analysed for quality (volume, count, motility, morphology). Firefighter semen parameters were below WHO reference values across multiple parameters. Self-reported rates of miscarriage were higher than the general population (22% vs. 12-15%) and in line with prior firefighter studies. Estimated daily intake for infants was above reference values for multiple chemicals in breast milk. More frequent fire incident exposure (more than once per fortnight), longer duration of employment (≥15 years) or not always using a breathing apparatus demonstrated significantly higher concentrations across a range of investigated chemicals. Findings of this study warrant further research surrounding the risk occupational exposure has on reproduction.

Reproductive aging: biological pathways and potential interventive strategies

Reproductive aging is a natural process conserved across species and is well-known in females. It shows age-related follicle depletion and reduction of oocyte quality, eventually causing reproductive senescence and menopause. Although reproductive aging in males is not well noticed as in females, it also causes infertility and has deleterious consequences on the offspring. Various factors have been suggested to contribute to reproductive aging, including oxidative stress, mitochondrial defects, telomere shortening, meiotic chromosome segregation errors and genetic alterations. With the increasing trend of pregnancy age, it is particularly crucial to find interventions to preserve or extend human fertility. Studies in humans and model organisms have provided insights into the biological pathways associated with reproductive aging, and a series of potential interventive strategies have been tested. Here, we review factors affecting reproductive aging in females and males and summarize interventive strategies that may help delay or rescue the aging phenotypes of reproduction.

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.

Effect of male age on reproductive function: A comparison of young and middle-aged men

PURPOSE

There have been concerns regarding potential effects of older paternal age on male reproductive function. However, currently available data on this topic are insufficient and controversy exists. We analyzed semen characteristics and reproductive hormones in young men and middle-aged men to investigate the effect of age on male reproductive function.

MATERIALS AND METHODS

This study examined healthy males of reproductive age who visited a single infertility center from January 2016 to July 2021. The young group consisted of men who were less than 35 years-old, and the middle-age group consisted of men who were more than 45 years-old.

RESULTS

The two groups had no significant differences in sperm concentration ([89.9±59.4]×10⁶/mL vs. [104.4±82.1]×10⁶/mL, p=0.108) or sperm morphology (normal forms: 3.6%±1.5% vs. 3.4%±1.6%, p=0.131). However, the middle-age group had a smaller semen volume (3.2±1.5 mL vs. 2.5±1.4 mL, p<0.001), lower sperm motility (42.3%±9.8% vs. 31.2%±12.4%, p<0.001), lower progressive sperm motility (39.2%±10.3% vs. 28.4%±12.6%, p<0.001), and a higher serum follicle-stimulating hormone level.

CONCLUSIONS

Our results suggest that advanced male age might have a negative effect on fertility potential, as in women. This finding has important clinical implications because more couples are choosing to have children when they are older. Further studies on this issue, especially those that examine reproductive outcome, are warranted.

Reproductive axis ageing and fertility in men

Compared to women, increasing male age is not accompanied by such marked changes in reproductive function but changes certainly do happen. These include alterations to the hypothalamo-pituitary-testicular axis, with resultant implications for testosterone production and bioavailability as well as spermatogenesis. There is a decline in sexual function as men age, with a dramatic increase in the prevalence of erectile dysfunction after the age of 40, which is a marker for both clinically evident as well as covert coronary artery disease. Despite a quantitative decline in spermatogenesis and reduced fecundability, the male potential for fertility persists throughout adult life, however there are also increasingly recognised alterations in sperm quality and function with significant implications for offspring health. These changes are relevant to both natural and medically assisted conception.

Paternal age impairs in vitro embryo and in vivo fetal development in murine

The association between advanced paternal age and impaired reproductive outcomes is still controversial. Several studies relate decrease in semen quality, impaired embryo/fetal development and offspring health to increased paternal age. However, some retrospective studies observed no alterations on both seminal status and reproductive outcomes in older men. Such inconsistency may be due to the influence of intrinsic and external factors, such as genetics, race, diet, social class, lifestyle and obvious ethical issues that may bias the assessment of reproductive status in humans. The use of the murine model enables prospective study and owes the establishment of homogeneous and controlled groups. This study aimed to evaluate the effect of paternal age on in vitro embryo development at 4.5 day post conception and on in vivo fetal development at 16 days of gestation. Murine females (2–4 months of age) were mated with young (4–6 months of age) or senile (18–24 months of age) males. We observed decreased in vitro cleavage, blastocyst, and embryo development rates; lighter and shorter fetuses in the senile compared to the young group. This study indicated that advanced paternal age negatively impacts subsequent embryo and fetal development.

Selective Serotonin Reuptake Inhibitor (SSRI) Use is Not Associated With Impaired Semen Parameters

OBJECTIVE

To examine the association between selective serotonin reuptake inhibitor (SSRI) use and semen quality.

METHODS

We performed a retrospective review of all men undergoing semen analysis (SA) for fertility evaluation from 2002-2020 at a single academic medical center. Men were excluded if they had prior exposure to spermatotoxic medications, clomiphene citrate, gonadotropins, selective estrogen receptor modulators, or medical conditions known to impact male fertility. SSRI exposure was defined by an outpatient prescription within 90 days prior to any semen test. Differences between men with and without SSRI exposure were assessed with Wilcoxon rank sum for continuous variables and chi-squared testing for proportions. Univariable and multivariable linear regression models were fit to evaluate the relationship between SSRI use and individual semen parameters, controlling for age at the time of the semen analysis and non-SSRI drug use.

RESULTS

A total of 8861 men were identified, of whom 153 men (1.7%) were exposed to SSRIs prior to SA. Median age was 35 years (interquartile range: 32-39) and was similar between groups (P = .999). Non-SSRI medication use was significantly higher in men taking SSRIs (78.4% vs 23.3%, < .001). On univariable and multivariable analyses, SSRI exposure was not associated with differences in semen volume, sperm concentration, motility, total motile sperm count, or normal morphology.

CONCLUSION

In adult men undergoing fertility evaluation, SSRI exposure was not associated with impaired semen parameters. These data may help inform reproductive counseling and medical decision-making regarding SSRI use in men seeking paternity.

Age-Related Decline of Male Fertility: Mitochondrial Dysfunction and the Antioxidant Interventions

Mitochondria are structurally and functionally unique organelles in male gametes. Apparently, as the only organelles remaining in mature sperm, mitochondria not only produce adeno-sine triphosphate (ATP) through oxidative phosphorylation (OXPHOS) to support sperm mobility, but also play key roles in regulating reactive oxidation species (ROS) signaling, calcium homeostasis, steroid hormone biosynthesis, and apoptosis. Mitochondrial dysfunction is often associated with the aging process. Age-dependent alterations of the epididymis can cause alterations in sperm mitochondrial functioning. The resultant cellular defects in sperm have been implicated in male infertility. Among these, oxidative stress (OS) due to the overproduction of ROS in mitochondria may represent one of the major causes of these disorders. Excessive ROS can trigger DNA damage, disturb calcium homeostasis, impair OXPHOS, disrupt the integrity of the sperm lipid membrane, and induce apoptosis. Given these facts, scavenging ROS by antioxidants hold great potential in terms of finding promising therapeutic strategies to treat male infertility. Here, we summarize the progress made in understanding mitochondrial dysfunction, aging, and male infertility. The clinical potential of antioxidant interventions was also discussed.

Male Reproductive Health - study of a sperm donor population

OBJECTIVE

Every individual has the right to a safe and satisfactory sex and reproductive life. Therefore, several countries have made efforts to make Reproductive Health resources available to their populations. However, few results have been published regarding the policies implemented in Portugal. This study looked into the reproductive health status of the Portuguese male population.

METHODS

Sperm donor candidates from the Portuguese Public Gamete Bank registered between 2011 and 2018 were included in the study. Spermogram findings were evaluated with respect to sociodemographic and risk factors.

RESULTS

This is the first study performed in this population. We found that sperm quality has decreased throughout the last nine years, and that spermatozoa progressive motility is inversely correlated with the body mass index. An association between drug use and decreased sperm pH was also found.

CONCLUSIONS

Changes in sperm quality have important consequences in male fertility. Most of the identified causes of decreased sperm quality are modifiable factors and should therefore be addressed since an early age.

Anatomical Transcriptome Atlas of the Male Mouse Reproductive System During Aging

The elderly males undergo degenerative fertility and testicular endocrine function that jeopardize the reproductive health and well-being. However, the mechanisms underlying reproductive aging are unclear. Here, we tried to address this by investigating the phenotypes and transcriptomes of seven regions of the male mouse reproductive tract: the testis, efferent ductules, initial segment, caput, corpus and cauda epididymidis, and vas deferens, in adult (3 months) and aged (21 months) mice. Quantitative PCR, immunohistochemistry, immunofluorescent staining, and enzyme-linked immunosorbent assay were performed for the analysis of gene expression in mice, human tissues, and semen samples. Aged male mice showed both systematic and reproductive changes, and remarkable histological changes were detected in the testis and proximal epididymis. Transcriptomes of the male reproductive tract were mapped, and a series of region-specific genes were identified and validated in mouse and/or human tissues, including Protamine 1 (Prm2), ADAM metallopeptidase domain 28 (Adam28), Ribonuclease A family member 13 (Rnase13), WAP four-disulfide core domain 13 (Wfdc13), and Wfdc9. Meanwhile, age-related transcriptome changes of different regions of the male reproductive tract were characterized. Notably, increased immune response was functionally related to the male reproductive aging, especially the T cell activation. An immune response-associated factor, phospholipase A2 group IID (Pla2g2d), was identified as a potential biomarker for reproductive aging in mice. And the PLA2G2D level in human seminal plasma surged at approximately 35 years of age. Furthermore, we highlighted Protein tyrosine phosphatase receptor type C (Ptprc), Lymphocyte protein tyrosine kinase (Lck), Microtubule associated protein tau (Mapt), and Interferon induced protein with tetratricopeptide repeats 3 (Ifit3) as critical molecules in the aging of initial segment, caput, caput, and cauda epididymidis, respectively. This study provides an RNA-seq resource for the male reproductive system during aging in mice, and is expected to improve our understanding of male reproductive aging and infertility.

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.

Reciprocal translocation and Robertsonian translocation in relation to semen parameters: A retrospective study and systematic review

Reciprocal translocation and Robertsonian translocation are known to be causative factors of male infertility. However, the association between autosomal reciprocal translocation, Robertsonian translocation and semen parameters remains controversial. We performed a retrospective study and systematic review to investigate semen parameters in patients with autosomal reciprocal translocation or Robertsonian translocation. We recruited a total of 1,033 controls, 723 reciprocal translocation carriers and 326 Robertsonian translocation carriers. Men in the control, reciprocal translocation and Robertsonian translocation groups had a median age of 32.0 (95% CI, 32.0-33.0), 32.0 (95% CI, 32.0-33.0) and 33.0 (95% CI, 32.0-33.0) years respectively. Results showed that sperm concentration, total number per ejaculate, total motility, progressive motility of autosomal reciprocal translocation and Robertsonian translocation carriers were statistically lower than controls (p < .001). Eleven studies featuring 794 patients were enrolled in this systematic review. Compared with controls, autosomal reciprocal translocation and Robertsonian translocation carriers showed lower sperm concentration, total motility, progressive motility and normal morphology. Our results support the conclusion that sperm concentration, total number per ejaculate, total motility and progressive motility are significantly lower in autosomal reciprocal translocation and Robertsonian translocation carriers than in controls.

Developmental programming and ageing of male reproductive function

Developmental programming predisposes offspring to metabolic, behavioural and reproductive dysfunction in adult life. Evidence is accumulating that ageing phenotype and longevity are in part developmentally programmed in each individual. Unfortunately, there are few studies addressing the effects of developmental programming by maternal nutrition on the rate of ageing of the male reproductive system. This review will discuss effects of foetal exposure to maternal environmental challenges on male offspring fertility and normal ageing of the male reproductive system. We focus on several key factors involved in reproductive ageing such as decreased hormone production, DNA fragmentation, oxidative stress, telomere shortening, epigenetics, maternal lifestyle and nutrition. There is compelling evidence that ageing of the male reproductive system is developmentally programmed. Both maternal over- or undernutrition accelerate ageing of male offspring reproductive function through similar mechanisms such as decreased serum testosterone levels, increase in oxidative stress biomarkers in both the testes and sperm and changes in sperm quality. Importantly, even in adult life, exercise in male offspring of obese mothers improves adverse effects of programming on reproductive function. Maternal consumption of a low-protein diet causes transgenerational effects in progeny via the paternal line. The seminal fluid has effects on the intrauterine environment. Programming by male factors may involve more than just the sperm. Improving knowledge on developmental programming ageing interactions will improve not only male health and life span but also the health of future generations by reducing programming via the paternal line.

Male subfertility and oxidative stress

To date 15% of couples are suffering from infertility with 45-50% of males being responsible. With an increase in paternal age as well as various environmental and lifestyle factors worsening these figures are expected to increase. As the so-called free radical theory of infertility suggests, free radicals or reactive oxygen species (ROS) play an essential role in this process. However, ROS also fulfill important functions for instance in sperm maturation. The aim of this review article is to discuss the role reactive oxygen species play in male fertility and how these are influenced by lifestyle, age or disease. We will further discuss how these ROS are measured and how they can be avoided during in-vitro fertilization.

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.

Paternal age over 50 years decreases assisted reproductive technology (ART) success: A single UK center retrospective analysis

INTRODUCTION

To study whether paternal age exerts an effect, independent of maternal age, on the outcomes of fresh in vitro fertilization/ intracytoplasmic sperm injection (IVF/ICSI) cycles. Semen quality deteriorates with increasing paternal age; however, there is conflicting evidence for any impact paternal age may have on the outcome of IVF/ICSI. Several retrospective and prospective cohort studies have shown that paternal age increases the miscarriage rate and reduces the live birth rate. Some studies have shown no effect of paternal age on live birth rate or miscarriage rate. Studies involving donor oocytes have tended to show no independent effect of paternal age on assisted reproductive technology (ART) outcomes. The age at which paternal age may exert a significant deleterious effect on outcome is not known and there is no limit to paternal age in IVF/ICSI treatment.

MATERIAL AND METHODS

A single-center retrospective cohort study was carried out at the Centre for Reproductive and Genetic Health, London, UK. Included in the analysis were all couples with primary or secondary infertility undergoing IVF/ICSI cycles in which the male partner produced a fresh semen sample and the cycle proceeded to fresh embryo transfer. All cycles of IVF/ICSI that used donor oocytes-donor sperm, frozen sperm, cycles leading to embryo storage and cycles including preimplantation genetic testing (PGT-A/PGT-M)-were excluded from analysis. The primary outcome was live birth rate and secondary outcomes were clinical pregnancy rate and miscarriage rate. Multivariate logistic regression analysis with live birth as a dependent variable and maternal and paternal age class as independent variables was performed.

RESULTS

During the study period there were 4833 cycles, involving 4271 men, eligible for analysis; 1974/4833 (40.8%, 95% confiene intervals [CI] 39.5-42.2%) cycles resulted in a live birth. A significantly lower proportion of men over 51 years met World Health Organization semen analysis criteria (56/133, [42.1%, 95% CI 34.1-50.6]) compared with men under 51 years of age (2530/4138 [61.1%, 95% CI 60.0-62.6]) (p = 0.001). Both maternal and paternal age were retained in the multivariate model and for all maternal age subgroups the probability of live birth decreased with paternal age over 50 years (odds ratio [OR] 0.674, 95% CI 0.482-0.943) (p = 0.021). Paternal age over 50 years was not an independent predictor of miscarriage (OR 0.678, 95% CI 0.369-1.250) (p = 0.214).

CONCLUSIONS

Paternal age over 50 significantly affects the chance of achieving a live birth following ART. Paternal age does not independently affect the risk of miscarriage following ART. There should be a public health message for men not to delay fatherhood.

Reproductive aging and telomeres: Are women and men equally affected?

Successful reproduction is very important for individuals and for society. Currently, the human health span and lifespan are the object of intense and productive investigation with great achievements, compared to the last century. However, reproduction span does not progress concomitantly with lifespan. Reproductive organs age, decreasing the levels of sexual hormones, which are protectors of health through their action on several organs of the body. Thus, this is the starting point of the organismal decay and infertility. This starting point is easily detected in women. In men, it goes under the surface, undetected, but it goes, nevertheless. Regarding fertility, aging alters the hormonal equilibrium, decreases the potential of reproductive organs, diminishes the quality of the gametes and worsen the reproductive outcomes. All these events happen at a different pace and affecting different organs in women and men. The question is what molecular pathways are involved in reproductive aging and if there is a possible halting or even reversion of the aging events. Answers to all these points will be explained in the present review.

Effect of male age on pregnancy and neonatal outcomes in the first frozen-thawed embryo transfer cycles of IVF/ICSI treatment

BACKGROUND

The effect of male age on pregnancy outcomes after assisted reproductive technology (ART) treatment shown in the previous literature is controversial. In addition, the influence of male age on neonatal outcomes following ART treatment has less been investigated.

OBJECTIVES

The aim of this study was to evaluate the effect of male age on reproductive and neonatal outcomes in couples following ART treatment.

MATERIALS AND METHODS

A retrospective cohort study was performed in two centers for assisted reproduction from June 2010 to February 2019. A total of 5512 frozen-thawed embryo transfer (FET) cycles were included according to the criteria. The primary outcome measures were pregnancy and neonatal outcomes. Patients were categorized into five groups according to male age (younger than 30, 31-35, 36-40, 41-45, and older than 45), and the group younger than 30 years old was treated as the reference group.

RESULTS

The logistic regression analysis showed that clinical pregnancy and live birth were all no statistic difference among the male age-groups compared with the reference group (p values, 0.743, 0.979, 0.948, 0.28; p values, 0.823, 0.342, 0.817, 0.381, respectively). Furthermore, no significant differences were found in the preterm birth rate, child sex, neonatal malformation, birth weight, and gestational age (p > 0.05). The advanced male age was not associated with a higher risk of adverse neonatal outcomes.

DISCUSSION AND CONCLUSION

This study showed that there were no effects of male age on pregnancy or neonatal outcomes in infertile couples following their first FET cycles when females were younger than 36 years old.

Association between advanced paternal age and congenital heart defects: a systematic review and meta-analysis

STUDY QUESTION

Is there an association between advanced paternal age and congenital heart defects (CHD)?

SUMMARY ANSWER

Advanced paternal age is associated with a 16% increase in the overall odds of CHD.

WHAT IS KNOWN ALREADY

CHD are the most common congenital malformations. Several risk factors for CHD have been identified in the literature, but the association between advanced paternal age and CHD remains unclear.

STUDY DESIGN, SIZE, DURATION

We conducted a systematic literature search on MEDLINE and EMBASE (1960-2019) to identify studies assessing the association between advanced paternal age (≥35 years) and the risk of CHD, unrestrictive of language or sample size. We used a combination of Medical Subject Headings (MeSH) terms and free text words such as 'paternal age', 'paternal factors', 'father's age', 'parental age', 'heart', 'cardiac', 'cardiovascular', 'abnormalities, congenital', 'birth defects', 'congenital malformations' and 'congenital abnormalities'.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We included observational studies aiming at assessing the association between paternal age and CHD. The included population could be live births, fetal deaths and terminations of pregnancy for fetal anomaly. To be included, studies had to provide either odds ratios (OR) with their 95% confidence interval (CI) or sufficient information to recalculate ORs with 95% CIs per paternal age category. We excluded studies if they had no comparative group and if they were reviews or case reports. Two independent reviewers selected the studies, extracted the data and assessed risk of bias using a modified Newcastle-Ottawa Scale. We used random-effects meta-analysis to produce summary estimates of crude OR. Associations were also tested in subgroups.

MAIN RESULTS AND THE ROLE OF CHANCE

Of 191 studies identified, we included nine studies in the meta-analysis (9 917 011 participants, including 34 447 CHD), including four population-based studies. Five studies were judged at low risk of bias. Only one population-based study specifically investigated isolated CHD. The risk of CHD was higher with advanced paternal age (summary OR 1.16, 95% CI, 1.07-1.25). Effect sizes were stable in population-based studies and in those with low risk of bias.

LIMITATIONS AND REASONS FOR CAUTION

The available evidence did not allow to assess (i) the risk of isolated CHD in population-based studies, (ii) the association between paternal age and the risk for specific CHD and (iii) the association between paternal age and CHD after adjustment for other risk factors, such as maternal age.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings suggest that advanced paternal age may be a risk factor for CHD. However, because the association is modest in magnitude, its usefulness as a criterion for targeted screening for CHD seems limited.

STUDY FUNDING/COMPETING INTEREST(S)

None.

PROSPERO REGISTRATION NUMBER

CRD42019135061.