Advanced Paternal Age Affects the Sperm DNA Fragmentation Index and May Lead to Lower Good-quality Blastocysts

High risk of low birth weight in couples with advanced paternal age in in vitro fertilization treatment

BACKGROUND

With the development of socio-economic conditions and a shift in attitudes towards fertility, there has been a gradual increase in delayed childbearing since the 2000s. Age plays a significant role in the decline of fertility. However, we know very little about the association of paternal age with reproductive outcomes.

OBJECTIVES

To investigate the correlation between advanced paternal age and semen quality, embryo quality, pregnancy, and neonatal outcomes in IVF cycles.

MATERIALS AND METHODS

In this study, after excluding female partners aged ≥35 years, we analyzed data from 761 infertile couples who underwent in vitro fertilization cycles at the First Affiliated Hospital of USTC between June 2020 and March 2023. Cases were classified into three groups according to the age of the male: <35 years (530 infertile couples), 35 years ≤ paternal age <40 years (125 infertile couples), and ≥40 years (106 infertile couples). Then, we compared the general clinical data arising from in vitro fertilization cycles between the three groups, including semen parameters, embryonic parameters, and pregnancy and neonatal birth outcomes.

RESULTS

Data analysis showed that the duration of infertility and the incidence of secondary infertility were significantly higher in paternal age ≥35 years groups than those aged <35 years (all p < 0.05). We also observed a significant difference between ≥40 years and <35 years groups in terms of the normal fertilization rate, high-quality embryo rate, clinical pregnancy rate, miscarriage rate, live birth rate, Apgar scores, and the low birth weight neonatal rate (all p < 0.05). The group with paternal age ≥40 years showed statistically significant differences in terms of clinical pregnancy rate, miscarriage rate, live birth rate, and low birth weight on multivariable logistic regression (all p < 0.05).

CONCLUSION

The results of our study indicate that advanced paternal age (≥40 years) has a significant impact on the embryo quality, pregnancy outcome, and neonatal outcome. Paternal age over 40 years is a risk for in vitro fertilization success rate.

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

OBJECTIVES

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

STUDY DESIGN

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

RESULTS

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

CONCLUSIONS

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

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.

Paternal Age Amplifies Cryopreservation-Induced Stress in Human Spermatozoa

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

Semen Cryopreservation to Expand Male Fertility in Cancer Patients: Intracase Evaluation of Semen Quality

To preserve male fertility after diagnosis of any kind of cancer, a prompt assessment of the semen quality and an appropriate semen cryopreservation must be performed before radio-chemotherapy starts. The present work aims to evaluate the semen parameters at diagnosis of different cancer patients before cryopreservation and after thawing. Testicular tumors and lymphomas are among the most common cancers in younger patients, and while chemotherapy significantly increases patients' survival, it can epigenetically alter the semen fluid, resulting in temporary or permanent infertility. We analyzed data from the database of the Gamete Cryopreservation Center (Annunziata Hospital, CS; Italy) in the period of 2011-2020 from a cohort of 254 cancer patients aged 18-56 years. The evaluation was performed in a blind manner and anonymously recovered; the main parameters referring to semen quality were assessed in accordance with the WHO guidelines and decision limits (6th edition; 2021). The cancer types were as follows: testis cancers (TC; n = 135; 53.1%), hematological cancers (HC; n = 76; 29.9%), and other types of cancer (OC; n = 43; 17%). Comparing TC vs. HC (P1) and vs. OC (P2), TC had the worst semen quality: sperm number/mL (P1 = 0.0014; P2 = 0.004), total motility (P1 = 0.02; P2 = 0.07), progressive motility (P1 = 0.04; P2 = 0.05), viability (P1 = 0.01; P2 = 0.02), and percentage of atypical morphology (P1 = 0.05; P2 = 0.03). After semen thawing, viability and progressive motility recovery lowered, accounting for 46.82% and 16.75%, respectively, in the whole cohort; similarly, in the subgroups ascribed to TC, they showed the lowest recovery. Strong correlation existed between pre- and post-cryopreservation viability and progressive motility in the whole cohort (p < 0.001) and in the TC subgroup (p < 0.05). All cancer subgroups, to significantly different extents, had semen findings below the WHO reference values, suggesting diverse sperm susceptibilities to different cancers and cryodamage. Cancer and associated treatments epigenetically affect patients' semen quality, meaning cryopreservation should be considered a useful personalized prerogative for any kind of cancer in a timely manner.

Male reproductive ageing: a radical road to ruin

In modern post-transition societies, we are reproducing later and living longer. While the impact of age on female reproductive function has been well studied, much less is known about the intersection of age and male reproduction. Our current understanding is that advancing age brings forth a progressive decline in male fertility accompanied by a reduction in circulating testosterone levels and the appearance of age-dependent reproductive pathologies including benign prostatic hypertrophy and erectile dysfunction. Paternal ageing is also associated with a profound increase in sperm DNA damage, the appearance of multiple epigenetic changes in the germ line and an elevated mutational load in the offspring. The net result of such changes is an increase in the disease burden carried by the progeny of ageing males, including dominant genetic diseases such as Apert syndrome and achondroplasia, as well as neuropsychiatric conditions including autism and spontaneous schizophrenia. The genetic basis of these age-related effects appears to involve two fundamental mechanisms. The first is a positive selection mechanism whereby stem cells containing mutations in a mitogen-activated protein kinase pathway gain a selective advantage over their non-mutant counterparts and exhibit significant clonal expansion with the passage of time. The second is dependent on an age-dependent increase in oxidative stress which impairs the steroidogenic capacity of the Leydig cells, disrupts the ability of Sertoli cells to support the normal differentiation of germ cells, and disrupts the functional and genetic integrity of spermatozoa. Given the central importance of oxidative stress in defining the impact of chronological age on male reproduction, there may be a role for antioxidants in the clinical management of this process. While animal studies are supportive of this strategy, carefully designed clinical trials are now needed if we are to realize the therapeutic potential of this approach in a clinical context.

Paternal Age Matters: Association with Sperm Criteria's- Spermatozoa DNA Integrity and Methylation Profile

Advanced age has been reported to negatively affect sperm parameters and spermatozoa DNA integrity. A decline in sperm criteria was also associated with altered epigenetic marks such as DNA methylation with a potential downstream impact on in vitro fertilization success and clinical outcomes. The aim of the present retrospective study was to clarify the association between advanced paternal age (APA) and sperm parameters, DNA integrity and DNA methylation profile. A total of 671 patients consulting for infertility underwent sperm analysis, sperm DNA integrity assessment and methylation level measurement. The principal finding was that individuals over 40 years of age exhibit a significant increase in DNA fragmentation levels compared to the younger group (15% versus 9%, respectively, p = 0.04). However, there was no significant difference in DNA decondensation and sperm parameters in association with APA. In addition, a drop in the global methylation level was also found in men over 40 years (6% in the young group versus 2% in the old group, p = 0.03). As a conclusion, men over 40 years are at higher risk of elevated sperm DNA fragmentation and lower methylation level. Based on these observations, it is recommended that the assessment of sperm DNA fragmentation should be taken into consideration particularly after the age of 40. Our findings support the idea that paternal age is a crucial factor that should not be neglected during fertility evaluation and treatment since it is associated with epigenetics changes in sperm. Although the underlying mechanism remains to be clarified, we believe that environmental and professional exposure factors are likely involved in the process.