Search Results (668)

Varicocele is a common, potentially correctable condition associated with impaired male fertility. Despite being frequently encountered in clinical andrology, its pathophysiological mechanisms, diagnostic criteria, and therapeutic approaches remain areas of active investigation and debate. The authors conducted a comprehensive literature search, using the PubMed database, covering clinical studies, systematic reviews, meta-analyses, and current international guidelines from the past ten years. Emphasis was placed on studies investigating novel diagnostic modalities, therapeutic innovations, and prognostic markers. Emerging evidence supports the multifactorial pathophysiology of varicocele, involving oxidative stress, hypoxia, inflammatory pathways, and potential genetic predisposition. Biomarkers, including microRNAs, antisperm antibodies, and sperm DNA fragmentation, offer diagnostic and prognostic utility, though their routine clinical implementation requires further validation. Advances in imaging, such as shear wave elastography, may improve diagnostic accuracy. While microsurgical subinguinal varicocelectomy remains the gold standard, technological refinements and non-surgical alternatives are being explored. Indications for treatment have expanded to include selected cases of non-obstructive azoospermia, hypogonadism, and optimization for assisted reproduction, though high-level evidence is limited. Full article

This review examines the regulatory role of m6A methylation modification in embryo implantation, focusing specifically on its impact on uterine receptivity and decidualization. It offers a comprehensive examination of the essential theoretical research on m6A methylation, clarifying its molecular mechanisms and roles in uterine receptivity and decidualization. Furthermore, this review examined the effects of m6A methylation on endometrial-related diseases and early embryonic development. It synthesizes early findings and recent advancements in m6A methylation studies. Through a comprehensive analysis of relevant studies, this review offers novel insights into the molecular mechanisms underlying embryo implantation and suggests potential strategies for assisted reproductive technologies and the treatment of related disorders, thereby serving as a comprehensive reference for future research in this domain. Full article

Background: Previous research has linked hypertensive disorders of pregnancy (HDP) and long-term cardiovascular disease (CVD) with assisted reproductive technology (ART). It is not clear whether this reflects the background population cardiovascular profiles or whether ART independently increases the long-term risk for CVD and alters cardiovascular function. Furthermore, CVD has been associated with pathological cardiovascular function before and after the establishment of the disease. The aim of this study was to compare cardiac function in women attending for ART between those who had previous treatment and those who had not after controlling for demographic characteristics which have been shown to affect cardiovascular function. Methods: This was a prospective observational cohort study at a London fertility clinic. Women were consecutively enrolled between May 2021 and March 2022. Maternal demographics and cardiac function using transthoracic echocardiography were assessed before the current treatment cycle in the mid-luteal phase of the menstrual cycle. Maternal demographics included age, body mass index, smoking, race, and parity. Cardiovascular parameters included blood pressure and indices of left-ventricular systolic and diastolic function. Differences between cardiac variables after controlling for maternal demographics and history of previous ART were assessed by multivariate linear regression. Results: There were 232 healthy women who agreed to participate in the study; of those, 153 (58%) had undergone previous ART. After controlling for maternal demographic characteristics, previous assisted reproductive technology was not an independent predictor of cardiac function. Conclusions: Previous ART is not associated with significant changes in cardiac function. Full article

Bovine serum albumin (BSA), the most commonly used protein in preimplantation embryo culture media, performs a variety of physiological functions. However, its involvement in long-term effects remains largely unclear. To investigate its physiological importance in culture media, we examined the developmental and metabolic consequences of BSA deprivation during preimplantation stages in mice. Embryos cultured in BSA-free media during specific time windows exhibited impaired blastocyst formation, with continuous deprivation from the two-pronuclei (2PN) stage significantly reducing trophectoderm (TE) and inner cell mass (ICM) cell numbers (p < 0.05), indicating compromised viability. Short-term BSA deprivation similarly disrupted lineage allocation, underscoring the sensitivity of early embryos to nutrient availability during cell fate determination. Although birth rates remained unaffected, suggesting compensatory mechanisms, longitudinal analysis revealed sex-specific metabolic dysfunction. Male offspring developed progressive glucose intolerance by 16 weeks, exhibiting elevated fasting glucose levels (p < 0.05) and impaired glucose clearance, whereas females showed no significant alterations in glucose metabolism. This study demonstrates that protein restriction during the preimplantation period not only disrupts early embryonic development but also programs long-term metabolic dysfunction, underscoring the importance of optimizing culture conditions in assisted reproductive technologies to minimize future health risks. Full article

Semen collection is an important component of conservation and animal husbandry. Semen quality is generally improved using voluntary collection methods, particularly artificial vaginas (AVs). Most commercially available AVs are tube-shaped with few species-specific design augmentations. As genitalia are highly variable across taxa, incorporating species-specific genital morphologies into AV designs may enhance collected semen quality. We compared dolphin semen quality using: (1) silicone bioinspired artificial vaginas (BAVs) that reflect the internal shape of dolphin vaginas, and (2) manual stimulation. Sperm motility and kinematic parameters of five bottlenose dolphins (Tursiops sp.) were assessed using computer-aided sperm analysis (CASA). Sperm collected using BAVs showed non-significant increases in median progressive and rapid motility, and increases in median and mean linear motility, supporting a sexual selection functional hypothesis for the biodiverse vaginal folds unique to whales, dolphins, and porpoises. Sperm concentration decreased with BAV collection, while no consistent trends were detected in volume, pH, velocity, or plasma membrane integrity. Modifications to AVs for other species that incorporate genital morphologies may also optimize collected semen quality for application to artificial insemination. Full article

Immunological factors have gained growing recognition as key contributors to recurrent pregnancy loss (RPL) after in vitro fertilization (IVF), representing a major challenge in reproductive medicine. RPL affects approximately 1–2% of women trying to conceive naturally and up to 10–15% of those undergoing IVF, where overall success rates remain around 30–40% per cycle. An imbalance in maternal immunological tolerance toward the semi-allogeneic fetus during pregnancy may lead to miscarriage and implantation failure. IVF-related ovarian stimulation and embryo modification offer additional immunological complications that can exacerbate existing immune dysregulation. Recent advances in reproductive immunology have significantly deepened our understanding of the immune mechanisms underlying RPL following IVF, particularly highlighting the roles of regulatory T cells (T regs), natural killer cells, cytokine dysregulation, and disruptions in maternal–fetal immune tolerance. In order to better customize therapies, this evaluation incorporates recently discovered immunological biomarkers and groups patients according to unique immune profiles. Beyond conventional treatments like intralipid therapy and intravenous immunoglobulin, it also examines new immunomodulatory medications that target certain immune pathways, such as precision immunotherapies and novel cytokine modulators. We also discuss the debates over immunological diagnostics and therapies, such as intralipid therapy, intravenous immunoglobulin, corticosteroids, and anticoagulants. The heterogeneity of patient immune profiles combined with a lack of strong evidence highlights the imperative for precision medicine to improve therapeutic consistency. Novel indicators for tailored immunotherapy and emerging treatments that target particular immune pathways have encouraging opportunities to increase pregnancy success rates. Improving management approaches requires that future research prioritize large-scale clinical trials and the development of standardized immunological assessments. This review addresses the immunological factors in RPL during IVF, emphasizing underlying mechanisms, ongoing controversies, and novel therapeutic approaches to inform researchers and clinicians. Full article

Background/Objectives: Although biallelic pathogenic variants in different DNAH gene family members have been associated with infertility, the role of DNAH12 in this disorder is still incompletely understood. To date, few patients have been shown to have infertility due to biallelic variants in this gene. Here, we report two more unrelated patients with infertility who carry homozygous variants in DNAH12. Methods: This study included two male patients with primary infertility and oligoasthenoteratozoospermia (OAT). Patient 1 was a 32-year-old with 1.5 years of infertility and no chronic illnesses or prior assisted reproductive technologies (ARTs). Patient 2 was a 49-year-old with 24 years of infertility, a history of varicocelectomy, and the occasional use of PRN analgesics for bone pain. Using genome sequencing, we identified two homozygous variants: c.3757C>A, p. Pro1253Thr, and c.11086-1G>A, p.?, in patients 1 and 2, respectively. Results: Our findings add supportive evidence that DNAH12 is a gene implicated in rare cases of male infertility. The identification of these homozygous variants in two additional patients supports the association between DNAH12 variants and reproductive dysfunction. Conclusions: This study highlights the need for further research on the role of DNAH12, including functional studies to clarify the mechanisms contributing to infertility. Full article

Reproductive efficiency is a critical determinant of productivity and profitability in sheep farming. Traditional selection methods have largely relied on phenotypic traits and historical reproductive records, which are often limited by subjectivity and delayed feedback. Recent advancements in artificial intelligence (AI), including video tracking, wearable sensors, and machine learning (ML) algorithms, offer new opportunities to identify behavior-based indicators linked to key reproductive traits such as estrus, lambing, and maternal behavior. This review synthesizes the current research on AI-powered behavioral monitoring tools and proposes a conceptual model, ReproBehaviorNet, that maps age- and sex-specific behaviors to biological processes and AI applications, supporting real-time decision-making in both intensive and semi-intensive systems. The integration of accelerometers, GPS systems, and computer vision models enables continuous, non-invasive monitoring, leading to earlier detection of reproductive events and greater breeding precision. However, the implementation of such technologies also presents challenges, including the need for high-quality data, a costly infrastructure, and technical expertise that may limit access for small-scale producers. Despite these barriers, AI-assisted behavioral phenotyping has the potential to improve genetic progress, animal welfare, and sustainability. Interdisciplinary collaboration and responsible innovation are essential to ensure the equitable and effective adoption of these technologies in diverse farming contexts. Full article

The ability to model the earliest stages of human embryonic development in vitro using pluripotent stem cells offers researchers new ways to understand and interrogate the intricacies of implantation. It also raises important ethical and regulatory considerations, both those common to research involving human embryos, as well as those unique to stem cell-based embryo and endometrial models. This review examines the underpinning scientific discoveries that have led to the development of this rapidly expanding area of research, and how three-dimensional embryo models could be employed in advancing assisted reproductive technologies and understanding implantation failure. Importantly, we also discuss the ethical and legal implications and explore various governance models that have been proposed to foster responsibility and innovation in this area of research. Given the heightened interest in the scientific community on this topic, we finish on the question of how and when to involve the public in the development of this technology and its regulation. Full article

The incidence of sperm DNA fragmentation (SDF) in the ejaculate has garnered increasing attention in recent years due to its negative impact on reproductive outcomes. SDF involves two primary types of damage to the canonical double helix of DNA: single-strand breaks and double-strand breaks. Both of these can occur throughout the entire process of gametogenesis. Determining the precise causes of elevated SDF remains challenging, as it is influenced by a wide range of physiological processes and environmental factors. This review comprehensively explores the mechanisms underlying SDF, with a particular emphasis on the critical role of deoxyribonucleases (DNases) across different stages of male gamete development, as well as their relevance in assisted reproductive technologies (ART). Full article

The conservation of small and genetically vulnerable brown bear populations, such as the Cantabrian subpopulation in Spain, depends on developing species-specific assisted reproductive technologies and genetic resource banks. However, the lack of standardized sperm collection and cryopreservation protocols hinders their application. This study provides the first comparative analysis of sperm quality and proteomic profiles from three different origins: epididymal, pre-ejaculated, and ejaculated. Sperm quality parameters —motility and kinetic, viability, apoptosis, and oxidative stress— and protein expression were assessed. Although yields were similar, marked differences were observed in sperm quality and protein profiles. Sixty-three proteins involved in metabolism, stress response, and oxidative balance were differentially expressed depending on sperm origin. Epididymal sperm showed the highest viability and motility, lowest apoptosis, and a proteomic profile indicative of active spermatogenesis and enhanced oxidative stress defense. In contrast, ejaculated sperm had increased oxidative stress and reduced expression of metabolic proteins, while pre-ejaculated sperm exhibited lower motility, likely due to urine contamination and mitochondrial protein alterations, despite comparable viability and apoptosis. These findings offer novel insights into brown bear sperm biology and highlight the importance of sperm origin in developing optimized assisted reproduction strategies, ultimately supporting ex situ conservation efforts for this species. Full article

Sperm membrane potential (Em) hyperpolarization during capacitation is a functional hallmark of fertilizing ability and has been proposed as a predictive biomarker for conventional in vitro fertilization (IVF) success. However, it is unclear whether Em remains stable across ejaculates over time and can reliably guide assisted reproductive technology (ART) decisions in advance. Thus, we aimed to evaluate the temporal consistency of human sperm Em within individuals and assess its utility as a prognostic marker when measured days or weeks prior to IVF procedures. Em was assessed in capacitated and non-capacitated sperm from normospermic donors at three time points over 28 days, using a fluorometric assay. Capacitated values were compared to a −48.6 mV threshold previously associated with successful fertilization. Intra-donor Em variability and coefficients of variation (CV) were analyzed statistically. Our results showed that Em values exhibited significant intra-donor variability over time (p = 0.007), with approximately half of the donors crossing the −48.6 mV functional threshold across sessions. Capacitated sperm samples showed significantly greater variability than non-capacitated ones, with several donors exceeding a 30% CV cutoff. No consistent correlation was found between CV and mean Em values. While Em remains a promising functional marker when assessed on the day of IVF, its temporal variability undermines its reliability as a predictive tool for ART decisions made in advance. These findings underscore the importance of timing in functional sperm assessments and call for further studies to identify the physiological factors influencing Em stability. Full article

Background: Recurrent implantation failure (RIF) poses a major challenge in assisted reproductive technologies, with thin endometrium (≤7 mm) being a frequently observed yet poorly understood condition. Emerging evidence implicates nuclear factor-kappa B (NF-κB), a key transcription factor in inflammatory signaling, in impaired endometrial receptivity. However, its clinical relevance and prognostic value for live birth outcomes still need to be fully elucidated. Objective: We aim to evaluate the expression levels of endometrial NF-κB in patients with RIF and thin endometrium and to determine its potential as a predictive biomarker for live birth outcomes following IVF treatment. Methods: In this prospective case–control study, 158 women were categorized into three groups: Group 1 (RIF with thin endometrium, ≤7 mm, n = 52), Group 2 (RIF with normal endometrium, >7 mm, n = 38), and fertile controls (n = 68). NF-κB levels were assessed using ELISA and immunohistochemical histoscore. Pregnancy outcomes were compared across groups. ROC analysis and multivariable logistic regression were performed to assess the predictive value of NF-κB. Results: NF-κB expression was significantly elevated in Group 1 compared to Group 2 and controls (p = 0.0017). ROC analysis identified a cut-off value of 7.8 ng/mg for live birth prediction (AUC = 0.72, sensitivity 74%, specificity 75%). Multivariable analysis confirmed NF-κB is an independent predictor of live birth (p = 0.045). Histological findings revealed increased NF-κB staining in luminal and glandular epithelial cells in the thin endometrium group. Conclusions: Increased endometrial NF-κB expression is associated with thin endometrium and reduced live birth rates in RIF patients. NF-κB may serve not only as a biomarker of pathological inflammation but also as a prognostic tool for treatment stratification in IVF. Based on findings in the literature, the therapeutic targeting of NF-κB may represent a promising strategy to improve implantation outcomes. Full article

Sperm membrane stability is a key factor in determining sperm viability and fertilization capability, with broad implications ranging from basic reproductive biology to livestock breeding practices. This comprehensive review examines the structural and functional mechanisms underlying sperm membrane integrity, including defensive barrier functions, potentiometric ion channel regulation, and motility modulation that collectively optimize sperm survival, motility, and fertilization potential. Environmental factors such as temperature fluctuations, abnormal pH levels (outside the optimal 7.2–8.2 range), pathological conditions, and hormonal imbalances can compromise membrane stability by inducing oxidative stress and protein denaturation. Key regulatory proteins, notably NPC2 for cholesterol homeostasis, Flotillin proteins for lipid raft organization, and Annexin V for membrane repair mechanisms, demonstrate essential roles in maintaining structural integrity. In livestock reproduction, membrane stability research facilitates the optimization of cryoprotectant formulations and freezing protocols, resulting in 15–25% improvements in post-thaw sperm survival rates and enhanced artificial insemination success. These findings provide valuable insights for advancing assisted reproductive technologies and improving reproductive efficiency in animal husbandry. Full article

This study explored psychological distress and gender differences among couples diagnosed with unexplained infertility (UI) and undergoing evaluation for assisted reproductive treatment at the AOUP Santa Chiara Hospital in Pisa, Italy. A total of 21 heterosexual couples (N = 42) completed the Perceived Stress Scale (PSS), Depression Anxiety Stress Scale (DASS-21), Defeat Scale (DS), and Core-Fertility Quality of Life questionnaire (Core-FertiQol). Women reported significantly higher levels of anxiety and stress compared to men, as confirmed both by DASS-21 and PSS scores. No significant gender differences emerged either in depressive symptoms or defeat. In the Core-FertiQol, women scored higher in the Mind–Body component. Within-couple comparisons mirrored between-gender findings, with women showing higher distress. Despite elevated distress levels, women also demonstrated relatively preserved quality of life, possibly reflecting more adaptive coping strategies. The study provides preliminary support for the development of mindfulness-based interventions tailored to couples coping with UI. Further research with larger samples is needed to clarify gender-specific mechanisms and inform integrated psychological care in fertility settings. Full article