Infertility in the Aging Male

Impact of aging on spermatogenic function and reproductive outcomes in repro57 heterozygous male mice: A model for age-related infertility

PURPOSE

This study aims to investigate the histological changes, sperm parameters, and their impact on embryo development rates and offspring numbers in advanced-age male repro57 heterozygous mice, corresponding to approximately 40 years of age in humans.

METHODS

Sperm parameters were assessed in both young and advanced-age repro57 heterozygous mice, as well as in young and advanced-age wild-type mice. Additionally, testis weight and histological analysis of seminiferous tubules were conducted to identify degenerative changes. Male mice from each group were mated with young wild-type females to compare offspring numbers, and in vitro fertilization (IVF) was used to evaluate fertilization and blastocyst formation rates.

RESULTS

No significant differences in sperm concentration and motility were observed between young and aged wild-type mice or between young wild-type and young repro57 heterozygous mice. However, advanced-age repro57 heterozygous mice exhibited significantly lower sperm parameters and testis weight compared to advanced-age wild-type mice. Histological analysis revealed increased Sertoli cell vacuolation in the seminiferous tubules of advanced-age repro57 heterozygous mice. Additionally, these advanced-age mice exhibited significantly lower blastocyst formation rates and produced fewer offspring compared to advanced-age wild-type mice.

CONCLUSION

Advanced reproductive aging in repro57 heterozygous male mice is associated with marked senescence-like degenerative changes, leading to a decline in offspring numbers, attributed to increased Sertoli cell vacuolation and diminished sperm quality.

Telomere length in relation to fecundability and use of assisted reproductive technologies: the Norwegian Mother, Father, and Child Cohort Study

BACKGROUND

Telomere length (TL) has been reported to be associated with conditions such as endometriosis and polycystic ovary syndrome, with some studies finding associations with shorter TL and others with longer TL. In men, studies mostly report associations between shorter TL and sperm quality. To our knowledge, no studies have thus far investigated associations between TL and fecundability or the use of assisted reproductive technologies (ART).

METHODS

This study is based on the Norwegian Mother, Father, and Child Cohort (MoBa) Study and uses data from the Medical Birth Registry of Norway (MBRN). We included women (24,645 with genotype data and 1054 with TL measurements) and men (18,339 with genotype data and 965 with TL measurements) participating between 1998 and 2008. We investigated associations between leukocyte TL (LTL) and fecundability (defined as the probability to conceive within a given menstrual cycle), infertility (defined has having spent 12 months or more trying to conceive without success), and ART use. We also repeated the analyses using instrumental variables for LTL consisting of genetic risk scores for LTL and genetically predicted LTL.

RESULTS

Approximately 11% of couples had experienced infertility and 4% had used ART. LTL was not associated with fecundability in women (fecundability ratio [FR], 0.98; 95% confidence interval [CI], 0.92-1.04) or men (FR, 0.99; CI, 0.93-1.06), nor with infertility in women (odds ratio [OR], 1.03; CI, 0.85-1.24) or men (OR, 1.05; CI, 0.87-1.28). We observed an increased likelihood of using ART with increasing LTL in men (OR, 1.22; CI, 1.03-1.46), but not in women (OR, 1.10; CI, 0.92-1.31). No significant associations were observed using the instrumental variables for LTL.

CONCLUSIONS

We found no indication that LTL is a suitable biomarker for assessing fecundability, infertility, or ART use. Additional studies are required to replicate the association observed between LTL and ART use in men.

Testosterone therapy for functional hypogonadism in middle-aged and elderly males: current evidence and future perspectives

Population aging is a global phenomenon driving research focus toward preventing and managing age-related disorders. Functional hypogonadism (FH) has been defined as the combination of low testosterone levels, typically serum total testosterone below 300-350 ng/dL, together with manifestations of hypogonadism, in the absence of an intrinsic pathology of the hypothalamic-pituitary-testicular (HPT) axis. It is usually seen in middle-aged or elderly males as a product of aging and multimorbidity. This age-related decline in testosterone levels has been associated with numerous adverse outcomes. Testosterone therapy (TTh) is the mainstay of treatment for organic hypogonadism with an identifiable intrinsic pathology of the HPT axis. Current guidelines generally make weak recommendations for TTh in patients with FH, mostly in the presence of sexual dysfunction. Concerns about long-term safety have historically limited TTh use in middle-aged and elderly males with FH. However, recent randomized controlled trials and meta-analyses have demonstrated safe long-term outcomes regarding prostatic and cardiovascular health, together with decreases in all-cause mortality and improvements in various domains, including sexual function, body composition, physical strength, bone density, and hematopoiesis. Furthermore, there are numerous insightful studies suggesting additional benefits of TTh, for instance in cardio-renal-metabolic conditions. Specifically, future trials should investigate the role of TTh in improving symptoms and prognosis in various clinical contexts, including sarcopenia, frailty, dyslipidemia, arterial hypertension, diabetes mellitus, fracture risk, heart failure, stable angina, chronic kidney disease, mood disorders, and cognitive dysfunction.

Telomere length in relation to fecundability and use of assisted reproductive technologies: the Norwegian Mother, Father, and Child Cohort Study

In women, shorter telomeres have been reported to be associated with conditions such as endometriosis and polycystic ovary syndrome, whereas other studies have reported the opposite. In men, studies mostly report associations between shorter telomeres and sperm quality. To our knowledge, no studies have thus far investigated the associations between TL and fecundability or the use of ART. This study is based on the Norwegian Mother, Father, and Child Cohort (MoBa) Study and uses data from the Medical Birth Registry of Norway (MBRN). We included women (24,645 with genotype data and 1,054 with TL measurements) and men (18,339 with genotype data and 965 with TL measurements) participating between 1998 and 2008. We investigated the associations between leukocyte TL and fecundability, infertility, and the use of ART. We also repeated the analyses using instrumental variables for TL, including genetic risk scores for TL and genetically predicted TL. Approximately 11% of couples had experienced infertility and 4% had used ART. TL was not associated with fecundability among women (fecundability ratio [FR], 0.98; 95% confidence interval [CI], 0.92-1.04) or men (FR, 0.99; CI, 0.93-1.06), nor with infertility among women (odds ratio [OR], 1.03; CI, 0.85-1.24) or men (OR, 1.05; CI, 0.87-1.28). We observed an increased likelihood of using ART with increasing TL among men (OR, 1.22; CI, 1.03-1.46), but not among women (OR, 1.10; CI, 0.92-1.31). No significant associations were observed using the instrumental variables. Our results indicate that TL is a poor biomarker of fecundability, infertility and use of ART in MoBa. Additional studies are required to replicate the association observed between TL and ART in men.

Molecular mechanisms of mammalian sperm capacitation, and its regulation by sodium-dependent secondary active transporters

Background

Mammalian spermatozoa have to be "capacitated" to be fertilization-competent. Capacitation is a collective term for the physiological and biochemical changes in spermatozoa that occur within the female body. However, the regulatory mechanisms underlying capacitation have not been fully elucidated.

Methods

Previously published papers on capacitation, especially from the perspective of ions/channels/transporters, were extracted and summarized.

Results

Capacitation can be divided into two processes: earlier events (membrane potential hyperpolarization, intracellular pH rise, intracellular Ca2+ rise, etc.) and two major later events: hyperactivation and the acrosome reaction. Earlier events are closely interconnected with each other. Various channels/transporters are involved in the regulation of them, which ultimately lead to the later events. Manipulating the extracellular K+ concentration based on the oviductal concentration modifies membrane potential; however, the later events and fertilization are not affected, suggesting the uninvolvement of membrane potential in capacitation. Hyperpolarization is a highly conserved phenomenon among mammalian species, indicating its importance in capacitation. Therefore, the physiological importance of hyperpolarization apart from membrane potential is suggested.

Conclusion

The hypotheses are (1) hyperpolarizing Na+ dynamics (decrease in intracellular Na+) and Na+-driven secondary active transporters play a vital role in capacitation and (2) the sperm-specific potassium channel Slo3 is involved in volume and/or morphological regulation.

Age-related decline in spermatogenic activity accompanied with endothelial cell senescence in male mice

Male fertility decreases with aging, with spermatogenic decline being one of its causes. Altered testis environment is suggested as a cause of the phenotype; however, the associated mechanisms remain unclear. Herein, we investigated the age-related changes in testicular somatic cells on spermatogenic activity. The number and proliferation of spermatogonia significantly reduced with aging in mice. Interestingly, senescence-associated β-galactosidase-positive cells appeared in testicular endothelial cell (EC) populations, but not in germ cell populations, with aging. Transcriptome analysis of ECs indicated that senescence occurred in the ECs of aged mice. Furthermore, the support capacity of ECs for spermatogonial proliferation significantly decreased with aging; however, the senolytic-induced removal of senescent cells from aged ECs restored their supporting capacity to a comparable level as that of young ECs. Our results suggest that the accumulation of senescent ECs in the testis is a potential factor contributing to the age-related decline in spermatogenic activity.

Altered microRNA expression profiles of human spermatozoa in normal fertile men of different ages

MicroRNAs (miRNAs) are mediators of the aging process. The purpose of this work was to analyze the miRNA expression profiles of spermatozoa from men of different ages with normal fertility. Twenty-seven donors were divided into three groups by age (Group A, n = 8, age: 20-30 years; Group B, n = 10, age: 31-40 years; and Group C, n = 9, age: 41-55 years) for high-throughput sequencing analysis. Samples from 65 individuals (22, 22, and 21 in Groups A, B, and C, respectively) were used for validation by quantitative real-time polymerase chain reaction (qRT-PCR). A total of 2160 miRNAs were detected: 1223 were known, 937 were newly discovered and unnamed, of which 191 were expressed in all donors. A total of 7, 5, and 17 differentially expressed microRNAs (DEMs) were found in Group A vs B, Group B vs C, and Group A vs C comparisons, respectively. Twenty-two miRNAs were statistically correlated with age. Twelve miRNAs were identified as age-associated miRNAs, including hsa-miR-127-3p, mmu-miR-5100_L+2R-1, efu-miR-9226_L-2_1ss22GA, cgr-miR-1260_L+1, hsa-miR-652-3p_R+1, pal-miR-9993a-3p_L+2R-1, hsa-miR-7977_1ss6AG, hsa-miR-106b-3p_R-1, hsa-miR-186-5p, PC-3p-59611_111, hsa-miR-93-3p_R+1, and aeca-mir-8986a-p5_1ss1GA. There were 9165 target genes of age-associated miRNAs. Gene Ontology (GO) analysis of the target genes identified revealed enrichment of protein binding, membrane, cell cycle, and so on. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of age-related miRNAs for target genes revealed 139 enriched pathways, such as signaling pathways regulating stem cell pluripotency, metabolic pathways, and the Hippo signaling pathway. This suggests that miRNAs play a key role in male fertility changes with increasing age and provides new evidence for the study of the mechanism of age-related male fertility decline.

The role of red ginseng in men's reproductive health: a literature review

BACKGROUND

Red ginseng (RG) is a traditional herb commonly used in China, Korea, and other East Asian countries. Recently, it has demonstrated a better clinical value in men's reproductive health (MRH). The present review aimed to examine the effects of RG treatment on MRH.

RESULTS

Overall, 42 articles related to RG application in MRH were reviewed, of which 31 were animal experiments and 11 were clinical studies. Furthermore, this review analyzed the use of RG in some male reproductive diseases in clinical trials and determined the associated mechanisms of action. The mechanism of action of RG in MRH may be related to oxidative stress, regulation of sex hormones and spermatogenesis-related proteins, and anti-inflammation.

CONCLUSIONS

The application of RG for the treatment of male infertility, erectile dysfunction, and prostate diseases has the potential to contribute to MRH.

Expression profiles of circular RNAs in spermatozoa from aging men

BACKGROUND

Advanced paternal age (APA) is associated with decreased fertility, but the mechanism underlying APA remains unknown. CircRNAs have been reported to be ideal candidate biomarkers for diagnostic and therapeutic applications in many diseases and are also involved in spermatogenesis. Hence, we aimed to assess the circRNA expression profile of spermatozoa from aging men.

METHODS AND RESULTS

We recruited 6 subjects, including 3 in the younger group (men age < 40) and 3 in the APA group (men age ≥ 40). RNA sequencing was exploited to identify the expression profiles of circRNAs between the two groups. The expression levels of circRNAs were validated using real-time quantitative polymerase chain reaction (RT-qPCR). Kyoto Encyclopedia of Genes and Genomes biological pathway analysis and Gene Ontology analysis were performed to evaluate the functions of differentially expressed circRNAs (DE-circRNAs) between the two groups. In total, 18,787 circRNAs were sequenced in the spermatozoa of two groups. Our analysis revealed that there were 1056 downregulated circRNAs and 1228 upregulated circRNAs between the two groups, and KEGG analysis showed they were mainly involved in pathways including the DNA repair signaling pathway, meiotic recombination signaling pathway, and PI3K/AKT signaling pathway.

CONCLUSIONS

In conclusion, our study suggested that circRNAs play a vital role in spermatozoa from aging men and provided a fresh perspective on the specific regulatory mechanism of spermatozoa from aging men.

Obstetrical and Perinatal Outcomes Are Not Associated with Advanced Paternal Age in IVF or ICSI Pregnancies with Autologous Oocytes

BACKGROUND

In recent years, there has been an evident delay in childbearing and concerns have been raised about whether this increase in age affects reproductive outcomes. This study aimed to evaluate the effect of paternal age on obstetrical and perinatal outcomes in couples undergoing in vitro fertilization or intracytoplasmic sperm injection using autologous sperm and oocytes.

METHODS

This retrospective study evaluated obstetrical and perinatal outcomes from 14,125 couples that were arbitrarily divided into three groups according to paternal age at conception: ≤30 (n = 1164), 31-40 (n = 11,668) and >40 (n = 1293). Statistics consisted of a descriptive analysis followed by univariate and multivariate models, using the youngest age group as a reference.

RESULTS

The study showed significantly longer pregnancies for the fathers aged 31-40 compared to ≤30 years. However, there were no significant differences for the type of delivery, gestational diabetes, anaemia, hypertension, delivery threat, premature rupture of membranes, preterm birth, very preterm birth, and the neonate's sex, weight, low birth weight, very low birth weight, length, cranial perimeter, Apgar score and neonatal intensive care unit admission.

CONCLUSION

Despite our promising results for older fathers, as paternal age was not associated with clinically relevant obstetrical and perinatal outcomes, future well-designed studies are necessary as it has been associated with other important disorders.

Decreased Klotho Expression Causes Accelerated Decline of Male Fecundity through Oxidative Injury in Murine Testis

Oxidative stress is the etiology for 30-80% of male patients affected by infertility, which is a major health problem worldwide. Klotho protein is an aging suppressor that functions as a humoral factor modulating various cellular processes including antioxidation and anti-inflammation, and its dysregulation leads to human pathologies. Male mice lacking Klotho are sterile, and decreased Klotho levels in the serum are observed in men suffering from infertility with lower sperm counts. However, the mechanism by which Klotho maintains healthy male fertility remains unclear. Klotho haplodeficiency (Kl+/-) accelerates fertility reduction by impairing sperm quality and spermatogenesis in Kl+/- mice. Testicular proteomic analysis revealed that loss of Klotho predominantly disturbed oxidation and the glutathione-related pathway. We further focused on the glutathione-S-transferase (GST) family which counteracts oxidative stress in most cell types and closely relates with fertility. Several GST proteins, including GSTP1, GSTO2, and GSTK1, were significantly downregulated, which subsequently resulted in increased levels of the lipid peroxidation product 4-hydroxynonenal and apoptosis in murine testis with low or no expression of Klotho. Taken together, the loss of one Kl allele accelerates male fecundity loss because diminished antioxidant capability induces oxidative injury in mice. This is the first study that highlights a connection between Klotho and GST proteins.

Dietary total antioxidant capacity and the risk of developing asthenozoospermia: a hospital-based case-control study in China

STUDY QUESTION

Is dietary total antioxidant capacity (DTAC) associated with the odds of developing asthenozoospermia in Chinese men?

SUMMARY ANSWER

There is no statistically significant association between DTAC indices and the odds of developing asthenozoospermia.

WHAT IS KNOWN ALREADY

Both diet and oxidative stress may be related to sperm quality; however, few studies have investigated the association between DTAC and sperm quality.

STUDY DESIGN, SIZE, DURATION

This case-control study was conducted from June 2020 to December 2020. Those diagnosed with asthenozoospermia were assigned to the case group, whereas those with normal sperm parameters were assigned to the control group. Data from a total of 553 cases and 586 controls were included in the final analysis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Men who had been referred to the infertility clinic of Shengjing Hospital of China Medical University were enrolled. Dietary intake was assessed using a validated food frequency questionnaire. DTAC was based on ferric-reducing ability of plasma (FRAP), total oxygen radical absorbance capacity (T-ORAC), hydrophilic oxygen radical absorbance capacity (H-ORAC), lipophilic oxygen radical absorbance capacity (L-ORAC), total phenolics (TP), total radical-trapping antioxidant parameter (TRAP), and Trolox equivalent antioxidant capacity (TEAC). Asthenozoospermia was defined according to the criteria published in the fifth edition of the World Health Organization laboratory manual for the examination and processing of human semen.

MAIN RESULTS AND THE ROLE OF CHANCE

No significant association was observed between the DTAC indices and the odds of asthenozoospermia after multivariable adjustment (T3 vs T1, odds ratio (OR) = 0.99, 95% CI: 0.73-1.33 for FRAP; OR = 1.05, 95% CI: 0.77-1.42 for T-ORAC; OR = 0.88, 95% CI: 0.65-1.18 for H-ORAC; OR = 0.98, 95% CI: 0.71-1.34 for L-ORAC; OR = 1.03, 95% CI: 0.76-1.39 for TP; OR = 1.18, 95% CI: 0.87-1.59 for TRAP; and OR = 1.15, 95% CI: 0.85-1.55 for TEAC). Both additive and multiplicative interaction analyses suggested that smoking might modify the association of T-ORAC with the odds of developing asthenozoospermia (relative excess risk due to interaction = 0.45, 95% CI: 0.07-0.83, attributable proportion due to interaction = 0.46, 95% CI: 0.07-0.84 for additive interaction; P = 0.033 for multiplicative interaction).

LIMITATIONS, REASONS FOR CAUTION

Recall bias and protopathic bias were inevitable in this retrospective case-control study. The estimation accuracy of the DTAC indices may have also affected the findings.

WIDER IMPLICATIONS OF THE FINDINGS

To the best of our knowledge, this is the first study to specifically investigate whether an association exists between DTAC and the odds of developing asthenozoospermia. Although no significant association was found, this study provides novel information pertaining to the fields of nutrition and human reproduction.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the JieBangGuaShuai Project of Liaoning Province (2021JH1/10400050), the Shengjing Hospital Clinical Research Project (M0071), and the Outstanding Scientific Fund of Shengjing Hospital (M1150). All authors have no competing interests to disclose.

TRIAL REGISTRATION NUMBER

N/A.

Advanced Paternal Age Does Not Affect Medically-Relevant Obstetrical and Perinatal Outcomes following IVF or ICSI in Humans with Donated Oocytes

BACKGROUND

Concomitant with delays in childbearing, concerns have been raised of whether advanced paternal age is associated with adverse reproductive outcomes, but the evidence is controversial in part due to the uncertain threshold in which to consider advanced paternal age and confounding maternal factors. This retrospective study aimed to evaluate the effect of paternal age on reproductive outcomes related to the pregnancy and perinatal health of the offspring.

METHODS

We retrospectively evaluated 16,268 cases of patients who underwent IVF or ICSI (using autologous sperm and donated oocytes, between January 2008 and March 2020, at Spanish IVIRMA clinics. Patients were divided based on paternal age at conception [≤30 (n = 204), 31-40 (n = 5752), and >40 years (n = 10,312)], and the differences in obstetrical and perinatal outcomes were analyzed by descriptive analysis, followed by univariate and multivariate analysis.

RESULTS

Fathers 31-40 and >40 years old were associated with lower odds of caesarean delivery [AOR 0.63 (95% CI, 0.44-0.90; p = 0.012) and AOR 0.61 (95% CI, 0.41-0.91; p = 0.017), respectively] and longer pregnancies [ARC 5.09 (95% CI, 2.39-7.79; p < 0.001) and ARC 4.54 (95% CI, 1.51-7.58; p = 0.003), respectively] with respect to fathers ≤30 years old. Furthermore, fathers aged 31-40 years old had lower odds of having a female infant (AOR, 0.70; 95% CI, 0.49-0.99; p = 0.045) than those ≤30. The rest of obstetrical and perinatal outcomes, which we deemed more medically-relevant as they were considered serious for health, were comparable between groups with our adjusted model.

CONCLUSIONS

Despite this hopeful message to fathers of advanced paternal age, future studies should consider the short- and long-term outcomes of the offspring and try to better elucidate the associations of advanced paternal age with reproductive outcomes and the molecular mechanisms underlying the observed associations.

Infertility in Men: Advances towards a Comprehensive and Integrative Strategy for Precision Theranostics

Male infertility is an increasing and serious medical concern, though the mechanism remains poorly understood. Impaired male reproductive function affects approximately half of infertile couples worldwide. Multiple factors related to the environment, genetics, age, and comorbidities have been associated with impaired sperm function. Present-day clinicians rely primarily on standard semen analysis to diagnose male reproductive potential and develop treatment strategies. To address sperm quality assessment bias and enhance analysis accuracy, the World Health Organization (WHO) has recommended standardized sperm testing; however, conventional diagnostic and therapeutic options for male infertility, including physical examination and semen standard analysis, remain ineffective in relieving the associated social burden. Instead, assisted reproductive techniques are becoming the primary therapeutic approach. In the post-genomic era, multiomics technologies that deeply interrogate the genome, transcriptome, proteome, and/or the epigenome, even at single-cell level, besides the breakthroughs in robotic surgery, stem cell therapy, and big data, offer promises towards solving semen quality deterioration and male factor infertility. This review highlights the complex etiology of male infertility, especially the roles of lifestyle and environmental factors, and discusses advanced technologies/methodologies used in characterizing its pathophysiology. A comprehensive combination of these innovative approaches in a global and multi-centric setting and fulfilling the suitable ethical consent could ensure optimal reproductive and developmental outcomes. These combinatorial approaches should allow for the development of diagnostic markers, molecular stratification classes, and personalized treatment strategies. Since lifestyle choices and environmental factors influence male fertility, their integration in any comprehensive approach is required for safe, proactive, cost-effective, and noninvasive precision male infertility theranostics that are affordable, accessible, and facilitate couples realizing their procreation dream.

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.

Cellular Senescence and Aging in Myotonic Dystrophy

Myotonic dystrophy (DM) is a dominantly inherited multisystemic disorder affecting various organs, such as skeletal muscle, heart, the nervous system, and the eye. Myotonic dystrophy type 1 (DM1) and type 2 (DM2) are caused by expanded CTG and CCTG repeats, respectively. In both forms, the mutant transcripts containing expanded repeats aggregate as nuclear foci and sequester several RNA-binding proteins, resulting in alternative splicing dysregulation. Although certain alternative splicing events are linked to the clinical DM phenotypes, the molecular mechanisms underlying multiple DM symptoms remain unclear. Interestingly, multi-systemic DM manifestations, including muscle weakness, cognitive impairment, cataract, and frontal baldness, resemble premature aging. Furthermore, cellular senescence, a critical contributor to aging, is suggested to play a key role in DM cellular pathophysiology. In particular, several senescence inducers including telomere shortening, mitochondrial dysfunction, and oxidative stress and senescence biomarkers such as cell cycle inhibitors, senescence-associated secretory phenotype, chromatin reorganization, and microRNA have been implicated in DM pathogenesis. In this review, we focus on the clinical similarities between DM and aging, and summarize the involvement of cellular senescence in DM and the potential application of anti-aging DM therapies.

Early and late paternal contribution to cell division of embryos in a time-lapse imaging incubation system

The objective of this study was to investigate the impact of male age, semen quality and days of ejaculatory abstinence on embryo morphokinetics. A total of 1,220 zygotes obtained from 139 couples in a private in vitro fertilisation centre were analysed. The timing of specific events from the point of insemination, such as timings to pronuclei appearance and fading, to two, three, four, five, six, seven and eight cells and to blastulation were recorded. Multivariate linear regression analysis was used to evaluate the influence of paternal factors on embryo morphokinetic events. Paternal age was positively correlated with delayed cell cleavage and blastulation, and negatively associated with implantation rate, and clinical pregnancy and live-birth chances. The ejaculatory abstinence was inversely correlated with the implantation rate. Inverse relationships were observed between semen parameters (sperm count, progressive sperm motility, total motile sperm count and morphology) and the timing of specific events during embryo development. Sperm morphology was also positively associated with implantation rate and pregnancy and live-birth chances. Increased paternal age and ejaculatory abstinence, and poor semen quality correlate with delayed cell cleavage and blastulation and negatively impact intracytoplasmic sperm injection outcomes.

Molecular Drivers of Developmental Arrest in the Human Preimplantation Embryo: A Systematic Review and Critical Analysis Leading to Mapping Future Research

Developmental arrest of the preimplantation embryo is a multifactorial condition, characterized by lack of cellular division for at least 24 hours, hindering the in vitro fertilization cycle outcome. This systematic review aims to present the molecular drivers of developmental arrest, focusing on embryonic and parental factors. A systematic search in PubMed/Medline, Embase and Cochrane-Central-Database was performed in January 2021. A total of 76 studies were included. The identified embryonic factors associated with arrest included gene variations, mitochondrial DNA copy number, methylation patterns, chromosomal abnormalities, metabolic profile and morphological features. Parental factors included, gene variation, protein expression levels and infertility etiology. A valuable conclusion emerging through critical analysis indicated that genetic origins of developmental arrest analyzed from the perspective of parental infertility etiology and the embryo itself, share common ground. This is a unique and long-overdue contribution to literature that for the first time presents an all-inclusive methodological report on the molecular drivers leading to preimplantation embryos’ arrested development. The variety and heterogeneity of developmental arrest drivers, along with their inevitable intertwining relationships does not allow for prioritization on the factors playing a more definitive role in arrested development. This systematic review provides the basis for further research in the field.

Do aging, drinking, and having unhealthy weight have a synergistic impact on semen quality?

PURPOSE

To evaluate if age, alcohol consumption, and body mass index (BMI) have synergistic effects on seminal quality, and to rank these factors based on their impact on semen.

METHODS

Retrospective study of 9464 patients attending an andrology laboratory. Data on patients' age and daily alcohol intake were provided by the patients. BMI was recorded in the laboratory. Seminal parameters evaluated were volume, sperm concentration and total count, motility, morphology, viability, nuclear maturity, and membrane functional integrity.

RESULTS

All the seminal parameters evaluated were affected by the synergistic interaction Age x BMI, suggesting that this combination is more potent in affecting semen quality. The variables sperm morphology and nuclear maturity seemed to be especially susceptible since they were affected by the three synergistic interactions. In the logistic regression analysis, age was the most powerful factor since it impacted first on five of the nine parameters, impacting mainly on sperm motility, viability, and morphology, with no effects on sperm count. On the contrary, BMI impacted first in sperm concentration and total sperm count; which was confirmed also by the logistic predictions analysis. Alcohol consumption impacted first on membrane functional integrity and nuclear maturity. A J-shaped association between BMI or alcohol consumption with semen quality was found in the multivariate analysis.

CONCLUSION

The factors considered in this study showed a synergistic negative impact on semen quality, being age and unhealthy weight the most important ones. Reducing the exposure to lifestyle risk factors may be promising for improving sperm quality in infertile patients.

Fluorescence-Based Ratiometric Analysis of Sperm Centrioles (FRAC) Finds Patient Age and Sperm Morphology Are Associated With Centriole Quality

A large proportion of infertility and miscarriage causes are unknown. One potential cause is a defective sperm centriole, a subcellular structure essential for sperm motility and embryonic development. Yet, the extent to which centriolar maladies contribute to male infertility is unknown due to the lack of a convenient way to assess centriole quality. We developed a robust, location-based, ratiometric assay to overcome this roadblock, the Fluorescence-based Ratiometric Assessment of Centrioles (FRAC). We performed a case series study with semen samples from 33 patients, separated using differential gradient centrifugation into higher-grade (pellet) and lower-grade (interface) sperm fractions. Using a reference population of higher-grade sperm from infertile men with morphologically standard sperm, we found that 79% of higher-grade sperm of infertile men with substandard sperm morphology have suboptimal centrioles (P = 0.0005). Moreover, tubulin labeling of the sperm distal centriole correlates negatively with age (P = 0.004, R = -0.66). These findings suggest that FRAC is a sensitive method and that patient age and sperm morphology are associated with centriole quality.

Influence of age on sperm characteristics evaluated by light and electron microscopies

The impact of male aging on male fertility has only recently become of interest to the scientific community. This study aims to assess the relationship between age and fertility among a sample of men, considering the individual and pathological characteristics. In this retrospective study data of semen analysis and medical history of 1294 Italian male patients were considered. Semen analysis was performed by light microscopy and transmission electron microscopy mathematically elaborated. A generalized linear model was used to explore the influence of male age on semen quality, considering as confounders wine consumption, smoking habits, presence of varicocele, consanguinity and positive semen bacteriological analysis and urethral swab. The mean age of the participants was 36.41 ± 6.379. Male aging without impact of confounders was correlated with a decrease in sperm concentration and motility and an increased in sperm necrosis. Sperm concentration and progressive motility were negatively related to the presence of confounders as wine consumption (sperm motility), urogenital infection (sperm concentration and motility), varicocele (sperm concentration) and consanguinity (sperm motility). Urogenital infection, varicocele and consanguinity positively correlated with sperm necrosis. The most important finding was the observation of a negative effect of male aging on sperm parameters such as concentration, motility, and viability. It is possible to hypothesize age-dependent changes of testicular environment, probably related to reactive oxygen species production. The demonstration, in a large sample of patients, that aging influences sperm quality strongly motivates further research focused on the mechanisms involved in this phenomenon and its effects on offspring fitness.

Incomplete proline catabolism drives premature sperm aging

Infertility is an increasingly common health issue, with rising prevalence in advanced parental age. Environmental stress has established negative effects on reproductive health, however, the impact of altering cellular metabolism and its endogenous reactive oxygen species (ROS) on fertility remains unclear. Here, we demonstrate the loss of proline dehydrogenase, the first committed step in proline catabolism, is relatively benign. In contrast, disruption of alh-6, which facilitates the second step of proline catabolism by converting 1-pyrroline-5-carboxylate (P5C) to glutamate, results in premature reproductive senescence, specifically in males. The premature reproductive senescence in alh-6 mutant males is caused by aberrant ROS homeostasis, which can be countered by genetically limiting the first committed step of proline catabolism that functions upstream of ALH-6 or by pharmacological treatment with antioxidants. Taken together, our work uncovers proline metabolism as a critical component of normal sperm function that can alter the rate of aging in the male reproductive system.

[Prevalence of male infertility in a university hospital in Morocco]

INTRODUCTION

infertility in couples has become a public health problem in recent years. It can be related to a problem in the male, female or both. Men infertility accounts for 40% of cases. In Morocco, most studies have focused on the causes and risk factors for male infertility. The purpose of our study was to assess the prevalence of male infertility and semen parameters in infertile men or in men at high risk of developing infertility in a tertiary hospital in Rabat.

METHODS

we conducted an analysis of 482 patients referred for evaluation of infertility in the couple or as part of preoperative assessment of varicocele or testicular ectopia. Demographic data, risk factors for infertility, primary or secondary infertility were recorded for each patient. Semen parameters were assessed and interpreted according to WHO standards updated in 2010 based on studies of factors associated with their disturbance.

RESULTS

the average age of patients was 35.35±8.81 years. Primary infertility was found in 61.8% of cases. The most common risk factors for infertility were tobacco followed by varicocele and infection. Spermogram was altered in 53.1% of cases. The most common abnormality was sperm vitality issues (36.9%) followed by spermatic concentration (29.7%) and morphology (29.3%). Age was the unique factor which had a significant impact on spermogram (p=0.002). Abnormalities in mobility were detected in patients ≥31 years, sperm vitality issues in patients aged 34 years, abnormalities in morphology in patients aged 35 years and concentration in patients aged 37 years. Azoospermia was found in 16.4% of cases and was mainly associated with primary infertility. Oligo-astheno-teratozoospermia was the most common association (26.2%).

CONCLUSION

male infertility is common in our context. The major risk factor is age. Mobility is the earliest parameter achieved.

The association between hidradenitis suppurativa and male and female infertility: A population-based study

BACKGROUND

Endocrine and metabolic associations have been recently reported in patients with hidradenitis suppurativa (HS); however, fertility was only rarely investigated in women and not at all in men.

OBJECTIVE

To evaluate the association of HS with male and female infertility.

METHODS

A cross-sectional, matched controlled, population-based study was designed. The association between HS and male and female infertility was evaluated in patients with HS (n = 4191) and age- and gender-matched controls (n = 20 941), while utilising the Clalit Health Services databases, the largest community-based health maintenance organisation in Israel.

RESULTS

Hidradenitis suppurativa was associated with infertility in males and females over all reproductive-age groups, especially among individuals aged 36-45 years (OR 4.50, 95%CI 2.55-7.93, P < 0.001), and in female patients (OR 3.10, 95%CI 2.57-3.74, P < 0.001). After adjustment for demographic and clinical factors, the association remained significant only in females (OR 1.26 95%CI 1.04-1.55, P < 0.05).

CONCLUSION

Patients with HS are at increased risk of infertility, particularly females and patients in the 36- to 45-year age group. Physicians should take the additional physiological and psychological burden of infertility among HS patients into account, primarily among female patients at procreative age.

Is there an association between paternal age and aneuploidy? Evidence from young donor oocyte-derived embryos: a systematic review and individual patient data meta-analysis

BACKGROUND

Delayed parenthood, by both women and men, has become more common in developed countries. The adverse effect of advanced maternal age on embryo aneuploidy and reproductive outcomes is well known. However, whether there is an association between paternal age (PA) and embryonic chromosomal aberrations remains controversial. Oocyte donation (OD) is often utilized to minimize maternal age effects on oocyte and embryo aneuploidy, thus providing an optimal model to assess the effect of PA. Several studies have revealed a higher than expected rate of aneuploidy in embryos derived from young oocyte donors, which warrants examination as to whether this may be attributed to advanced PA (APA).

OBJECTIVE AND RATIONALE

The objective of this systematic review and individual patient data (IPD) meta-analysis is to evaluate existing evidence regarding an association between PA and chromosomal aberrations in an OD model.

SEARCH METHODS

This review was conducted according to PRISMA guidelines for systematic reviews and meta-analyses. Medline, Embase and Cochrane databases were searched from inception through March 2020 using the (MeSH) terms: chromosome aberrations, preimplantation genetic screening and IVF. Original research articles, reporting on the types and/or frequency of chromosomal aberrations in embryos derived from donor oocytes, including data regarding PA, were included. Studies reporting results of IVF cycles using only autologous oocytes were excluded. Quality appraisal of included studies was conducted independently by two reviewers using a modified Newcastle-Ottawa Assessment Scale. A one-stage IPD meta-analysis was performed to evaluate whether an association exists between PA and aneuploidy. Meta-analysis was performed using a generalized linear mixed model to account for clustering of embryos within patients and clustering of patients within studies.

OUTCOMES

The search identified 13 032 references, independently screened by 2 reviewers, yielding 6 studies encompassing a total of 2637 IVF-OD cycles (n = 20 024 embryos). Two 'low' quality studies using FISH to screen 12 chromosomes on Day 3 embryos (n = 649) reported higher total aneuploidy rates and specifically higher rates of trisomy 21, 18 and 13 in men ≥50 years. One 'moderate' and three 'high' quality studies, which used 24-chromosome screening, found no association between PA and aneuploidy in Day 5/6 embryos (n = 12 559). The IPD meta-analysis, which included three 'high' quality studies (n = 10 830 Day 5/6 embryos), found no significant effect of PA on the rate of aneuploidy (odds ratio (OR) 0.97 per decade of age, 95% CI 0.91-1.03), which was robust to sensitivity analyses. There was no association between PA and individual chromosome aneuploidy or segmental aberrations, including for chromosomes X and Y (OR 1.06 per decade of age, 95% CI 0.92-1.21). Monosomy was most frequent for chromosome 16 (217/10802, 2.01%, 95% CI 1.76-2.29%) and trisomy was also most frequent for chromosome 16 (194/10802, 1.80%, 95% CI 1.56-2.06%).

WIDER IMPLICATIONS

We conclude, based on the available evidence, that APA is not associated with higher rates of aneuploidy in embryos derived from OD. These results will help fertility practitioners when providing preconception counselling, particularly to older men who desire to have a child.

The sperm centrioles

Centrioles are eukaryotic subcellular structures that produce and regulate massive cytoskeleton superstructures. They form centrosomes and cilia, regulate new centriole formation, anchor cilia to the cell, and regulate cilia function. These basic centriolar functions are executed in sperm cells during their amplification from spermatogonial stem cells during their differentiation to spermatozoa, and finally, after fertilization, when the sperm fuses with the egg. However, sperm centrioles exhibit many unique characteristics not commonly observed in other cell types, including structural remodeling, centriole-flagellum transition zone migration, and cell membrane association during meiosis. Here, we discuss five roles of sperm centrioles: orchestrating early spermatogenic cell divisions, forming the spermatozoon flagella, linking the spermatozoon head and tail, controlling sperm tail beating, and organizing the cytoskeleton of the zygote post-fertilization. We present the historic discovery of the centriole as a sperm factor that initiates embryogenesis, and recent genetic studies in humans and other mammals evaluating the current evidence for the five functions of sperm centrioles. We also examine information connecting the various sperm centriole functions to distinct clinical phenotypes. The emerging picture is that centrioles are essential sperm components with remarkable functional diversity and specialization that will require extensive and in-depth future studies.

Genetic counseling for advanced paternal age: A survey of genetic counselors' current practice

Advanced paternal age (APA) has no formal definition, though many publications utilize the cutoff of fathers >40 years of age. The literature demonstrates an association between APA and certain conditions including de novo autosomal dominant disorders, birth defects, and neuropsychiatric conditions. This study surveyed 165 genetic counselors within the National Society of Genetic Counselors to assess their current approach to APA. t Tests, analysis of variance, logistic regression, and chi-squared tests were performed on quantitative data, and content analysis was applied to qualitative data. Although most respondents have discussed APA with a patient (88%), there was no consensus on what age cutoff constitutes APA: >40 (N = 53, 37.9%), >45 (N = 61, 43.6%), >50 (N = 24, 17.1%), or >55 (N = 2, 1.4%). Those who discussed APA were more likely to be prenatal counselors, see more patients per week, be board certified, or be familiar with current APA guidelines. Respondents agreed the literature supports the association of APA with deleterious outcomes (mean agreement = 8.2, median = 8 on a 1 = strongly disagree to 10 = strongly agree). Individuals who discussed APA and were board certified had higher agreement. Content analysis confirmed agreement that the literature supports an association between APA and deleterious outcomes (documented in responses from 31.5% of prenatal respondents, 17.8% others) but noted that available testing and screening options for associated conditions are limited (34.4% of prenatal respondents, 17.4% others). Prenatal and non-prenatal respondents reported similar agreement with the statement that APA is associated with deleterious outcomes. However, most non-prenatal respondents were unfamiliar with current guidelines (80%), and presumably as a result, were also less likely to discuss APA with their patients. Our study identified a need to disseminate information regarding APA and current guidelines to genetic counselors, particularly non-prenatal and those with less experience.

Oxidative Stress is Associated with Reduced Sperm Motility in Normal Semen

Infertility is among the most serious medical problems worldwide. Male factors contribute to 40%-50% of all infertility cases, and approximately 7% of men worldwide are affected by infertility. Spermatozoa are extremely vulnerable to oxidative insult. Oxidative stress results in axonemal damage and increased midpiece sperm morphological defects, which lead to reduced sperm motility. The aim of the study is to evaluate the association between sperm motility and the levels of selected antioxidants, cytokines, and markers of oxidative damage in the seminal plasma.The study group included 107 healthy males, who were split into two subgroups based on the percentage of motile spermatozoa after 1 hr: low motility (LM, n = 51) and high motility (HM, n = 56).The glucose-6-phosphate dehydrogenase (G6PD) activity was 52% lower in the LM group compared to that in the HM group. The level of malondialdehyde (MDA) was 12% higher in the LM group compared to that in the HM group. Similarly, the median values of interleukin (IL)-1β, IL-10, IL-12, and tumor necrosis factor alpha (TNF-α) were higher in the LM group than those in the HM group. Results of the present study revealed that the percentage of motile spermatozoa after 1 hr correlated positively with the levels of IL-1β, IL-10, IL-12, and TNFα.The lower motility of spermatozoa in healthy men is associated with a decreased activity of G6PD and increased levels of cytokines, which may be related to increased oxidative stress in seminal plasma that manifests as an increased level of MDA.

Knowledge gaps in the understanding of fertility among non-medical graduate students

Objective

To assess knowledge of female and male fertility among students enrolled in a Master of Business Administration (MBA) program.

Design

Web-based cross-sectional survey.

Setting

Academic setting.

Patient(s)

Not applicable.

Intervention(s)

None.

Main Outcome Measure(s)

Knowledge of how female and male age impacts reproduction, fecundability, and success rates with in vitro fertilization (IVF).

Result(s)

A total of 133 female and male MBA students completed the survey. Nearly 10% of participants were not aware that women are born with a fixed number of oocytes and that oocyte quantity and quality decline with age. More than 30% of participants overestimated fecundability in women aged ≥35 years, and >50% overestimated IVF success rates in women older than 40 years. Fifteen percent of participants did not know that men have stem cells in the testes, and >25% were not aware that men experience a decrease in sperm concentration and quality with age. Nearly 30% believed that a man’s age never impacts reproductive outcomes. Less than 30% of participants correctly estimated fecundability and IVF success rates based on male age.

Conclusion(s)

These data highlight important knowledge gaps in a highly educated group of MBA students, most whom desire future childbearing. Specifically, there is a lack of understanding of both male and female reproductive aging and an overestimation of treatment success. As delayed childbearing continues, particularly among those with high educational attainment, attention should be focused on introducing broad fertility education at a younger age to improve future reproductive success.

Is there a correlation between paternal age and aneuploidy rate? An analysis of 3,118 embryos derived from young egg donors

OBJECTIVE

To investigate a possible correlation between chromosomal aberrations and paternal age, analyzing embryos derived from young oocyte donors, with available preimplantation genetic testing for aneuploidy results from day 5/6 trophectoderm biopsy obtained by next-generation sequencing for all 24 chromosomes.

DESIGN

Retrospective cohort study.

SETTING

Canadian fertility centre.

PATIENT(S)

A total of 3,118 embryos from 407 male patients, allocated into three paternal age groups: group A, ≤39 years (n = 203); group B, 40-49 years (n = 161); group C, ≥50 years (n = 43).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The primary outcomes were aneuploidy, euploidy, mosaicism, and blastocyst formation rates. Secondary endpoints were comparison of specific chromosome aneuploidy, segmental and complex (involving two chromosomes + mosaicism >50%) aneuploidy, and analysis of overall percentage of chromosomal gains and losses within each group.

RESULT(S)

The study included 437 in vitro fertilization (IVF) antagonist cycles using 302 oocyte donors in which preimplantation genetic testing for aneuploidy was performed. Overall, 70.04% of embryos were euploid, 13.9% were aneuploid, and 16.06% were mosaic. No significant differences among paternal age groups A, B, and C were found in euploidy rates (69.2%, 70.6%, 71.4%, respectively), aneuploidy rates (14.7%, 12.8%, 13.9%, respectively) or mosaicism rates (16.1%, 16.6%, 13.6%; respectively). The fertilization rate was lower in group C compared with group B (76.35% vs. 80.09%). No difference was found in blastocyst formation rate between the study groups (median 52% [interquartile range, 41%, 67%] vs. 53% [42%, 65%] vs. 52% [42%, 64%], respectively). A generalized linear mixed model regression analysis for embryo ploidy rates found older oocyte donor age to be independently associated with embryo aneuploidy (odds ratio = 1.041; 95% CI, 1.009-1.074). The rate of segmental aneuploidies was significantly higher in the older versus younger paternal age group (36.6% vs. 19.4%).

CONCLUSION(S)

No association was found between paternal age and aneuploidy rates in embryos derived from IVF cycles using young oocyte donors, after adjusting for donor, sperm, and IVF cycle characteristics. Advanced paternal age ≥ 50, compared with younger paternal ages, was associated with a lower fertilization rate and increased rate of segmental aberrations.

Biologically infallible? Men's views on male age-related fertility decline and sperm freezing

Trends in people having children later in life and increasing evidence of male age-related fertility decline (ARFD) has led some to propose sperm freezing as a suitable response. However, little consideration has been given to how men might respond to such a proposal, and there has been a paucity of empirical data to inform such a consideration. This paper arises from in-depth, semi-structured interviews with men (n = 25) who do not have children but want or expect to have them in the future. Data on men's perceptions of male ARFD and sperm freezing are presented and discussed in accordance with theoretical and conceptual tools relating to reproductive masculinity, biomedicalisation, gendered risk perception and meanings of sperm and masculinity. It suggests that that men's overall lack of concern regarding male ARFD and resistance towards ideas of sperm freezing result not only from a lack of exposure to evidence regarding male ARFD but are also shaped by ideals of reproductive masculinity, and may indicate resistance towards the idea of reproductive control. It argues that these positions perpetuate a gender unequal politicisation of ARFD and perpetuate particular gendered subjectivities relating to culpability and responsibility for guarding against risks of ARFD.

Association between X-ray repair cross-complementing group 1 Arg399Gln polymorphism and male infertility: An update meta-analysis

Numerous studies concentrate on the association between X-ray repair cross-complementing group 1 (XRCC1) gene polymorphism and male infertility; however, the results remain inconclusive and inconsistent. Hence, this meta-analysis was conducted to get a precise estimation of the correlation. PubMed, Web of Science, Embase, Scopus and China National Knowledge Infrastructure (CNKI) databases were searched to identify the all relevant studies before 3 May 2020. Summary odds ratios (ORs) and 95% confidence intervals (95% CIs) were used to assess the strength of the association. Finally, six studies with 1,886 cases and 1,212 controls were included in our study. The result indicated that XRCC1 Arg399Gln polymorphism was significantly associated with male infertility under allelic model (A-allele vs. G-allele: OR = 1.183, p = .003), heterozygote genetic model (AA vs. GA: OR = 1.256, p = .027), recessive genetic model (AA vs. GG + GA: OR = 1.279, p = .012) and dominant genetic model (AA + GA vs. GG: OR = 1.218, p = .026). In addition, in Asian subgroup, statistic correlation remained significant in allelic model (A-allele vs. G-allele: OR = 1.145, p = .025) with rare heterogeneity (I²  = 0%). In summary, our meta-analysis suggested that XRCC1 Arg399Gln polymorphism was significantly associated with male infertility and the A-allele might be a risk factor for this disease, especially in Asians.

Male age: negative impact on sperm DNA fragmentation

The main goal of semen processing in Assisted Reproductive Techniques (ART) is to select sperm with good viability and, at the same time, remove Reactive Oxygen Species (ROS) sources (such as leukocytes) and reduce the percentage of morphologically abnormal sperm for fertility treatment. We performed a comparative analysis on sperm DNA fragmentation after Density Gradient Centrifugation (DGC) using products sold by two competing companies. Our results showed comparable DNA Fragmentation Index (DFI) after treatment with both DGC products. However, in both cases, a comparable number of samples do not benefit from the treatment. Interestingly, increasing evidences indicated that male age has a negative impact on sperm DNA fragmentation, but the mechanisms underlying age-dependent patterns of sperm decline have not yet been fully understood. Thus, we performed a comparative analysis of DFI before and after treatment with DGC products in age-stratified sample populations. Our results showed a worsening of the baseline DFI in the eldest group and the benefits of DGC on sperm DNA were compromised. In conclusion, our work consolidates the current evidences suggesting that both paternal and maternal aging, critically affects reproductive success.

Association between polymorphisms in the XRCC1 gene and male infertility risk: A meta-analysis

BACKGROUND

X-ray repair cross-complementing group 1 (XRCC1) single nucleotide polymorphisms (SNPs) might correlate with male infertility susceptibility. This association has been described; however, the findings remain inconsistent. Consequently, this meta-analysis was conducted to characterize the relationship between XRCC1 SNPs and male infertility susceptibility.

METHODS/MAIN RESULTS

Studies were systematically searched in databases to evaluate the association between SNPs of XRCC1 and infertility in males. The effect measures chosen were the 95% confidence intervals (95% CIs) and odds ratios (ORs). A total of 7 studies, including 6 case-controlled studies on XRCC1 Arg399Gln and 3 case-controlled studies on XRCC1 Arg194Trp, were included. Ultimately, the results of this analysis revealed that XRCC1 Arg399Gln SNPs were significantly associated with infertility in males in homozygote comparisons (GG vs GA+AA: OR = 0.614, 95% CI: 0.40-0.937, P = .024). This meta-analysis did not demonstrate a relationship between XRCC1 Arg194Trp and male infertility risk.

CONCLUSIONS

Our study indicated that XRCC1 Arg399Gln polymorphism was associated with a significantly decreased male infertility risk, but not XRCC1 Arg194Trp.

Body mass index and age correlate with antioxidant supplementation effects on sperm quality: Post hoc analyses from a double-blind placebo-controlled trial

Spermatozoa are vulnerable to lack of energy and oxidative stress as a result of elevated levels of reactive oxygen species. Therefore, it is essential that appropriate nutrients are available during maturation. This randomised, double‐blind, placebo‐controlled trial investigated the effect of 6‐month supplementation with carnitines and other micronutrients on sperm quality in 104 subjects with oligo‐ and/or astheno‐ and/or teratozoospermia with or without varicocele. Semen analyses were done at the beginning and end of the treatment. In addition to main analyses, post hoc analyses for age and body mass index (BMI) were carried out. Results were interpreted by dividing the population into two age and BMI classes. In 94 patients who completed the study, all sperm parameters increased in supplemented patients compared to the placebo group. A significant (p = .0272) difference in supplementation efficacy was observed for total motility on patients with varicocele and BMI < 25. In the same group, also the progressive motility was significantly superior (p = .0159). For Responder analysis, total motility results were confirmed in both the cited group (p = .0066) and in the varicocele group with BMI < 25 and age < 35 (p = .0078). This study suggests that supplementation is more effective in subjects with varicocele younger than 35 years with BMI < 25.

Preoperative follicle-stimulating hormone: A factor associated with semen parameter improvement after microscopic subinguinal varicocelectomy

INTRODUCTION

Currently, there exists no serum biomarker to predict patients likely to benefit from varicocelectomy. The purpose of this study was to assess the association between baseline follicle-stimulating hormone (FSH) and semen parameter changes after subinguinal microscopic varicocelectomy.

METHODS

We retrospectively reviewed all men who underwent microscopic subinguinal varicocelectomy between August 2015 and October 2018. Pre- and postoperative semen analyses were stratified per total motile sperm count (TMSC): TMSC <5, 5-9, and >9 million (based on TMSC required for in vitro fertilization, intrauterine insemination [IUI], and natural conception, respectively). Then, variables were analyzed to determine the correlation with postoperative TMSC values and upgrade in TMSC category.

RESULTS

Among the 66 men analyzed, 55 (83.3%) and 11 (16.7%) had a preoperative TMSC of <5 million and 5-9 million, respectively. A total of 33 (50%) patients upgraded in TMSC category, 26 of them achieving levels corresponding to natural conception and seven achieving those of IUI. Additionally, a significant correlation was observed between postoperative TMSC and preoperative TMSC (r=0.528; p<0.001), and preoperative FSH (r=-0.314; p=0.010). A lower preoperative FSH (odds ratio [OR] 0.82; 95% confidence interval [CI] 0.68-0.98; p=0.028) and a higher preoperative TMSC (OR 1.37; 95% CI 1.06-1.76; p=0.015) were associated with upgrade in TMSC category.

CONCLUSIONS

Lower preoperative FSH and higher TMSC are associated with improvement in TMSC category after varicocelectomy, although small sample size limited the study. FSH can be useful to identify men who are most likely to benefit from varicocele repair.

Recent advances in understanding and managing male infertility

Infertility is a prevalent condition affecting an estimated 70 million people globally. The World Health Organization estimates that 9% of couples worldwide struggle with fertility issues and that male factor contributes to 50% of the issues. Male infertility has a variety of causes, ranging from genetic mutations to lifestyle choices to medical illnesses or medications. Recent studies examining DNA fragmentation, capacitation, and advanced paternal age have shed light on previously unknown topics. The role of conventional male reproductive surgeries aimed at improving or addressing male factor infertility, such as varicocelectomy and testicular sperm extraction, have recently been studied in an attempt to expand their narrow indications. Despite advances in the understanding of male infertility, idiopathic sperm abnormalities still account for about 30% of male infertility. With current and future efforts examining the molecular and genetic factors responsible for spermatogenesis and fertilization, we may be better able to understand etiologies of male factor infertility and thus improve outcomes for our patients.

ENU-induced mutant allele of Dnah1, ferf1, causes abnormal sperm behavior and fertilization failure in mice

Given attention to both contraception and treatment of infertility, there is a need to identify genes and sequence variants required for mammalian fertility. Recent unbiased mutagenesis strategies have expanded horizons of genetic control of reproduction. Here we show that male mice homozygous for the ethyl-nitroso-urea-induced ferf1 (fertilization failure 1) mutation are infertile, producing apparently normal sperm that does not fertilize oocytes in standard fertilization in vitro fertilization assays. The ferf1 mutation is a single-base change in the Dnah1 gene, encoding an axoneme-associated dynein heavy chain, and previously associated with male infertility in both mice and humans. This missense mutation causes a single-amino-acid change in the DNAH1 protein in ferf1 mutant mice that leads to abnormal sperm clumping, aberrant sperm motility, and the inability of sperm to penetrate the oocyte's zona pellucida; however, the ferf1 mutant sperm is competent to fertilize zona-free oocytes. Taken together, the various mutations affecting the DNAH1 protein in both mouse and human produce a diversity of phenotypes with both subtle and considerable differences. Thus, future identification of the interacting partners of DNAH1 might lead to understanding its unique function among the sperm dyneins.