Search Results (310)

Ambient heat exposure reduces male fertility in mammals with scrotal testes. Our previous work has demonstrated that some stallions are more susceptible to ambient heat-related subfertility than others, yet the mechanism for heat-induced subfertility remains uncertain, limiting both diagnosis and preventative measures. This study sought to define how the phenotype of stallions susceptible to heat-induced subfertility differs from that of more resilient animals, by measuring the systemic (blood plasma) and localized (reproductive tract) inflammatory and oxidative stress markers of sperm concentration, sperm motility assessments, total antioxidant capacity (TAC; in blood and seminal plasma), malondialdehyde (MDA; in blood and seminal plasma), oxidized guanine species (8-OH-2dG; in blood plasma and spermatozoa DNA), sperm DNA damage (assessed via Halo, SCSA (Sperm Chromatin Structure Assay) and CMA3 (Chromomycin A3)), and c-reactive protein (CRP; in blood plasma). Post-breeding dismount semen samples (n = 357) and blood plasma samples (n = 97) were collected from 31 stallions at commercial thoroughbred studs throughout one breeding season (NSW, Australia). A subset of stallions (16%) was deemed heat-induced subfertility-susceptible (HISS) stallions. These animals showed reduced seminal plasma antioxidant capacity, increased systemic and localized lipid peroxidation, and distinct systemic inflammatory response. Seminal antioxidant capacity was found to be strongly associated with impaired sperm motility (r = 0.739 * vs. r = −0.059). The plasma c-reactive protein of heat-susceptible stallions correlated to heat exposure (r = 0.597 *) and affected sperm motilities (r = −0.527 **, r = −0.434 *). Systemic oxidative DNA damage (8-OH-2dG) also increased following heat events (r = 0.862 ***) and correlated with fertility losses (FCP: r = −0.740 **, PCP: r = −0.603 *). Non-HISS stallions displayed greater variability in systemic antioxidant status and robust response following heat exposure (r = 0.307 *) and localized antioxidant capacity was more strongly correlated to systemic antioxidant capacity than in the heat-susceptible group (r = 0.897 *** vs. r = 0.482 **). We demonstrate that impaired antioxidant responses, altered redox balance and suppressed acute-phase inflammatory signalling are key features associated with heat-induced subfertility in stallions and highlight biomarkers that could be used to identify animals with heat-susceptible fertility. Full article

Biliverdin (BV) and bilirubin (BR) are established endogenous antioxidants and immune modulators in other organ systems; however, their roles in the male genital tract remain undefined. The aim of this study was to quantify both bile pigments in human seminal plasma using a fluorescent protein biosensor and to examine their associations with basic semen parameters. We analyzed forty-two semen samples from men undergoing infertility evaluation. Biliverdin predominated over bilirubin in 88.1% of samples. Biliverdin concentration ranged from 51.8 to 611.2 nM, whereas bilirubin ranged from 19.7 to 240.7 nM. The mean total amounts per ejaculate were 1054 pmol for biliverdin and 280 pmol for bilirubin. The total amount of bilirubin in the ejaculate was positively correlated with total sperm count (Rs = 0.47; p = 0.028), whereas biliverdin showed no significant association (Rs = 0.21; p = 0.723). Oligozoospermic samples had significantly lower bilirubin concentrations (p < 0.001) and lower total bilirubin amounts (p < 0.005). Teratozoospermic samples exhibited significantly higher biliverdin concentrations (p < 0.05). This study provides the first simultaneous quantification of biliverdin and unconjugated bilirubin in human seminal plasma and identifies distinct associations with sperm quality. These findings suggest that bile pigments may reflect localized redox-related processes in the male genital tract and may influence male fertility potential. Full article

Smoking is a major lifestyle factor associated with impaired male reproductive health, affecting both active smokers and individuals exposed to secondhand smoke. It also represents a significant source of cadmium (Cd) exposure, a toxic metal associated with altered sperm quality. This study aimed to evaluate the association between active and passive smoking and semen parameters, sperm DNA fragmentation, and chromatin decondensation, as well as cadmium (Cd) and zinc (Zn) levels in seminal plasma. A total of 280 men from infertile couples were included and categorized into three groups: 104 non-smokers (control), 90 active smokers, and 86 passive smokers. Semen samples were analyzed according to the WHO 2021 guidelines. Cadmium and zinc concentrations in seminal plasma were determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES), and sperm DNA fragmentation and chromatin decondensation were evaluated. The findings indicated that both active and passive smoking were associated with impaired semen parameters, increased sperm DNA fragmentation and chromatin decondensation, decreased zinc levels, and elevated cadmium concentrations in seminal plasma. Full article

To evaluate seminal oxidative stress, antioxidant defense, apoptosis-related activity, and Sertoli cell biomarkers in infertile men with grade 3 varicocele versus normozoospermic controls, and to assess postoperative changes after varicocelectomy. This prospective observational case–control study included 39 infertile men with grade 3 clinical varicocele and 44 normozoospermic controls. Seminal plasma levels of Malondialdehyde (MDA), 8-hydroxy-2′-deoxyguanosine (8-OHdG), superoxide dismutase (SOD), glutathione peroxidase-1 (GPx-1), reduced glutathione (GSH), nuclear factor erythroid 2–related factor 2 (NRF2), Kelch-like ECH-associated protein 1 (KEAP1), caspase-3, anti-Müllerian hormone (AMH), and inhibin B were measured by ELISA. Testicular volume, semen parameters, and diagnostic performance were also evaluated. Compared with controls, patients with varicocele had lower testicular volumes and impaired semen parameters. Seminal 8-OHdG and caspase-3 levels were higher, whereas SOD and inhibin B levels were lower. Baseline MDA, GPx-1, GSH, NRF2, KEAP1, and AMH levels did not differ significantly. After varicocelectomy, sperm concentration, total sperm count, progressive and total motility, total motile sperm count, morphology, and round cell count improved significantly. Postoperatively, caspase-3, MDA, and KEAP1 decreased, whereas SOD, GPx-1, GSH, NRF2, and inhibin B increased significantly. 8-OHdG showed a borderline decrease, and AMH remained unchanged. SOD showed the best diagnostic performance. Grade 3 varicocele is associated with oxidative DNA damage, impaired antioxidant defense, increased apoptotic signaling, and altered Sertoli cell-related seminal biomarkers. Varicocelectomy partially restores redox homeostasis, which may contribute to improved spermatogenic function. Full article

Taurine is abundant in seminal plasma and is involved in redox balance, osmoregulation, and sperm membrane stability. However, its role in protecting dairy goat bucks against heat stress-associated declines in sperm quality remains unclear. In this study, eighteen Guanzhong dairy goat bucks were assigned to three groups: control (NC), field heat stress (HS), and HS with taurine supplementation (HS + Tau). Heat stress reduced seminal plasma taurine abundance and was associated with metabolic reprogramming, impaired sperm quality, disturbed redox homeostasis, and decreased LH and testosterone levels. Specifically, HS reduced sperm motility, viability, membrane integrity, and kinematic performance, increased sperm abnormalities, and shortened in vitro sperm survival time. Taurine supplementation alleviated these adverse changes and shifted the seminal plasma metabolome toward a more homeostatic profile. Metabolomic analysis indicated that HS was associated with the accumulation of long-chain acylcarnitines in seminal plasma. Complementary mouse and TM4 Sertoli cell experiments provided preliminary mechanistic support, suggesting that taurine may partially protect Sertoli cell tight-junction proteins, particularly ZO-1, under heat- and acylcarnitine-related stress, and may be associated with the modulation of p38/AKT signaling. Collectively, these findings suggest that taurine alleviates heat stress-induced declines in sperm quality in dairy goat bucks, at least in part, by modulating seminal plasma metabolism. Full article

This review provides a comparative examination of current methods for evaluating fertility and semen quality in mammals, with emphasis on livestock species. It is based on a structured search and analysis of 316 academic publications retrieved from major scientific databases, including Elsevier, Springer, Taylor & Francis, and MDPI, as well as other repositories, covering literature published between 1938 and 2025. This review examines advanced semen analysis techniques, including computer-assisted semen analysis (CASA) systems and assays for assessing chromatin integrity, DNA damage, seminal plasma composition, sperm membrane proteins, and functional parameters such as migration capacity, membrane integrity, acrosomal status, capacitation, morphology, viability, concentration, motility, and volume. Methods for semen collection are also outlined. The synthesis focuses on the comparative assessment of techniques and recent findings for major ruminant and monogastric livestock species: cattle (Bos taurus and Bos indicus), buffalo (Bubalus bubalis), sheep (Ovis aries), goats (Capra hircus), and pigs (Sus domesticus). A brief historical overview of assisted insemination is presented, incorporating relevant procedures and managerial factors that affect fertility outcomes. Advances in genetics related to reproductive health are also discussed. This synthesis seeks to integrate existing knowledge and guide future research in reproductive science for both animal production and human medicine. Full article

The field of extracellular vesicle (EV) research offers a compelling example of a biological concept refined through continuous methodological innovation. This review traces the historical trajectory of the discipline chronologically, beginning with early observations in haemostasis, from Malpighi’s descriptions of blood clots and Chargaff and West’s identification of a procoagulant sedimentable plasma fraction, to Wolf’s “platelet dust,” Crawford’s microparticles characterised by electron microscopy, and the seminal work by Stahl and Johnstone demonstrating regulated vesicle biogenesis during reticulocyte maturation via multivesicular bodies. We highlight a pivotal conceptual shift, from viewing EVs as cellular debris to recognising them as regulated “communicasomes,” catalysed by Raposo’s discovery of antigen-presenting exosomes and subsequent evidence for EV-mediated transfer of functional receptors and nucleic acids, including the influential and sometimes debated model proposed by Ratajczak. By integrating findings from matrix vesicles, plant-derived vesicles, and diverse tissue contexts, we frame EV release as an evolutionarily conserved process with profound implications for immunity, regeneration, oncology, and cardiovascular pathology. A second central aim of this review is practical and methodological. We map how the expansion of biological claims has driven urgent standardisation efforts, notably through the establishment of the International Society for Extracellular Vesicles (ISEV) and the successive MISEV guidelines (2014, 2018, 2023). These are complemented by community resources such as EV-TRACK, MIFlowCyt-EV, and the databases ExoCarta and Vesiclepedia. We summarise core experimental choices across isolation and characterisation techniques, including ultracentrifugation, size exclusion chromatography, density gradients, flow cytometry, nanoparticle tracking analysis, and electron microscopy, while outlining persistent bottlenecks in purity, standardised nomenclature, and experimental reproducibility. Finally, we provide concise biographical sketches of key contributors and an overview of major EV-focused journals and ISEV meetings that anchor consensus-building and the translation of fundamental knowledge into clinical and industrial applications. Full article

Male fertility is declining worldwide, with notable reductions in sperm counts, emphasizing the need for new therapeutic interventions. Atranorin (ATR), a lichen-derived secondary metabolite, exhibits strong antioxidant and anti-inflammatory activities. This study assessed the protective effects of ATR on type 1 diabetes (T1D)-induced reproductive dysfunction in rats. T1D was induced in male Wistar rats via a single intraperitoneal injection of alloxan at 150 mg/kg body weight (bw). ATR significantly ameliorated T1D-related reproductive damage. At 170 mg/kg bw, ATR reduced hyperglycemia by 66% and attenuated seminal inflammation, decreasing leukocyte infiltration (−51%) and myeloperoxidase (MPO) activity (−68%). Oxidative balance improved, as evidenced by increased total antioxidant status (TAS) (+203%) and decreased thiobarbituric acid reactive substances (TBARS) (−73%), hydrogen peroxide (H₂O₂) (−45%), and total oxidant status (TOS) (−70%). Steroidogenesis was restored through enhanced 3β-hydroxysteroid dehydrogenase (3β-HSD) (+65%) and 17β-hydroxysteroid dehydrogenase (17β-HSD) (+102%) activities, resulting in a 90% recovery of testosterone levels. Seminal plasma function improved, with increased fructose levels (+71%), normalized pH (7.4), and enhanced hyaluronidase (HYAL) (+71%), adenosine triphosphatase (ATPase) (+71%), and prostatic acid phosphatase (PAP) (+79%) activities. Fertility biomarkers, such as adenosine deaminase (ADA) (+148%) and lactate dehydrogenase-C4 (LDH-C4) (+62%), increased, and essential minerals Zn²⁺ (+72%), Ca²⁺ (+96%), Mg²⁺ (+84%), and Se (+57%) were restored. Consequently, sperm density (+87%), viability (+69%), and motility (+189%) improved, while abnormalities declined (−46%). Histological findings confirmed the restoration of spermatogenesis and epididymal maturation. ATR effectively counteracts diabetes-induced reproductive dysfunction by reducing oxidative and inflammatory stress while improving hormonal and seminal parameters. Full article

Background/Objectives: Cryptorchidism is a common cause of male infertility and often results in azoospermia. However, the metabolic perturbations underlying cryptorchidism complicated with azoospermia and their association with surgical sperm retrieval outcomes remain poorly defined. Methods: A total of 35 patients with cryptorchidism and azoospermia, as well as 40 controls with normal semen parameters, were enrolled in the study. Seminal plasma samples from all participants were subjected to metabolomic analysis. Additionally, some patients underwent micro-TESE; the association between metabolomic features and the success or failure of surgical sperm retrieval was further analyzed. Results: A total of 931 differential metabolites were identified between patients and controls, primarily enriched in lipid metabolism and amino acid metabolism pathways. Lipid metabolites were broadly downregulated in patients, while several inflammation-related metabolites, including Prostaglandin E2, were upregulated. Routine clinical parameters showed no significant differences between patients with successful and failed micro-TESE. However, metabolomic profiles effectively distinguished these two subgroups. These differential metabolites between the two subgroups were mainly involved in three key pathways: phenylalanine–tyrosine–tryptophan biosynthesis, aminoacyl-tRNA biosynthesis, and folate biosynthesis. Most metabolites in the first two pathways were downregulated in the successful retrieval group, while those in the folate biosynthesis pathway showed the opposite regulatory trend. Four metabolites, including Leucine, 7,8-Dihydroneopterin, L-Tyrosine and Pterin, exhibited robust predictive value for micro-TESE outcomes. Conclusions: This study reveals distinct metabolic signatures in patients of cryptorchidism with azoospermia. The identified metabolic biomarkers provide valuable references for clinical decision-making regarding micro-TESE, facilitating a personalized assessment of sperm retrieval feasibility. Full article

Conventional semen analysis frequently fails to identify the underlying pathophysiology of male infertility, which is a complicated clinical disease, especially in cases of idiopathic infertility. A growing body of research indicates that inflammation and oxidative stress (OS) are important and related factors in male reproductive failure. Excessive reactive oxygen species (ROS) promote lipid peroxidation, protein oxidation, mitochondrial dysfunction, and sperm DNA fragmentation, thereby compromising motility, morphology, and fertilizing capacity. Concurrently, pro-inflammatory mediators like interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor-alpha (TNF-α) are frequently found in the seminal plasma of infertile men and are linked to poor semen parameters and testicular dysfunction. It is crucial that oxidative and inflammatory pathways work together to create a self-sustaining pathophysiological cycle that exacerbates sperm damage and destabilizes the reproductive milieu. The diagnostic significance, clinical suitability, and limitations of oxidative stress and inflammation biomarkers, such as malondialdehyde (MDA), 8-hydroxy-2′-deoxyguanosine (8-OHdG), total antioxidant capacity (TAC), and specific inflammatory markers, are critically assessed in this comprehensive review. The lack of established diagnostic thresholds, methodological variation, and translational issues that still restrict their widespread clinical implementation are highlighted in particular. Additionally, the potential contribution of biomarker-guided approaches to focused therapy decisions and individualized patient management is explored. This study examines how oxidative and inflammatory markers may complement conventional male infertility assessments by supporting more precise, mechanism-based approaches in reproductive medicine, while addressing diagnostic readiness and translational limitations. Full article

Background/Objectives: Male infertility, including primary and secondary infertility, is significantly influenced by oxidative stress, which disrupts sperm function and fertility. Seminal plasma, a protein-rich fluid essential for sperm protection and function, represents a valuable source for identifying biomarkers through proteomic analysis. While previous studies have explored seminal plasma proteins in fertility, the specific proteomic changes associated with oxidative stress in secondary infertility remain unclear. This study aimed to characterize these alterations by analyzing seminal plasma from three groups: men with secondary infertility, fertile donors with high oxidative stress, and fertile donors without oxidative stress. Methods: Pooled semen samples from each group underwent quantitative proteomics analysis using advanced mass spectrometry, with subsequent bioinformatic analysis using tools like DAVID, STRING, and IPA for identifying differentially expressed proteins (DEPs). Results: Quantitative proteomic analysis identified 377 DEPs in secondary infertility and 523 DEPs in fertile donors with high oxidative stress compared to controls. Bioinformatic analysis revealed seven shared pathways, including acute-phase response signaling, organismal injury, cellular movement, cell-to-cell signaling, free radical scavenging, immune cell trafficking, and Hematological system development. Notably, C3 and SERPINA3 exhibited significant alterations, along with proteins involved in sperm motility, capacitation, and fertilization, suggesting their potential roles in impaired fertility. Conclusions: These findings underscore the link between oxidative stress and secondary infertility and highlight specific seminal plasma proteins as potential biomarkers and therapeutic targets for diagnosing and treating male infertility. Full article

In the male body, zinc accumulates most abundantly in prostatic cells, where it plays a key role in producing high amounts of citrate in seminal fluid. Intraprostatic accumulation of Zn increases during the development of benign prostatic hyperplasia (BPH), one of the most common diseases in men over 50 years of age. Continuing our investigations on intraprostatic androgens, in this study, we analyzed the mineral content (Zn, Ca, Cu, K, Mg, Mn, and Na) in the transitional zone (TZ) of the prostate using inductively coupled plasma optical emission spectrometry (ICP-OES). The concentrations of testosterone (T) and dihydrotestosterone (DHT) were determined by liquid chromatography–mass spectrometry (LC-MS). Group-wise and correlation analyses demonstrated a descriptive trend toward a volume-dependent increase in Zn concentrations within TZ tissue, whereas other elements exhibited heterogeneous covariance patterns; intraprostatic hormone levels, although elevated in larger prostates, showed no consistent linear correlations with elemental concentrations. Given the observational design of the present study, the reported tissue Zn profiles cannot be interpreted as evidence supporting supplementation in BPH, and any potential clinical implications warrant evaluation in rigorously designed interventional studies. Full article

Male infertility is increasingly recognized as a complex, multifactorial disorder that extends beyond abnormalities in conventional semen parameters. A growing body of evidence highlights oxidative stress, sperm DNA fragmentation (SDF), and epigenetic alterations as tightly interconnected mechanisms contributing to sperm dysfunction and impaired fertility. Reactive oxygen species, though vital for sperm maturation and signaling, can inflict extensive genomic and chromatin damage when their levels exceed the antioxidant capacity of the testis and seminal plasma. These redox-driven lesions not only compromise fertilization potential but may also influence embryonic development and offspring health. Clinical studies and meta-analyses consistently report that elevated SDF and redox imbalance are associated with reduced pregnancy and live birth rates, particularly in assisted reproductive technologies (ARTs). The use of testicular sperm in men with high ejaculated SDF appears to improve ART outcomes, although long-term safety data remain limited. Advances in redox and genomic diagnostics, including assays for oxidation–reduction potential, SDF, and sperm epigenetic profiling, have opened new avenues for precision-based andrology, enabling targeted antioxidant, metabolic, and surgical interventions. Nonetheless, methodological variability, lack of assay standardization, and insufficient longitudinal follow-up constrain the full clinical translation of these findings. This review synthesizes evidence linking OS, SDF, and epigenetic alterations, highlighting their mechanistic crosstalk and translational relevance in the personalized management of male infertility. Full article

Conventional semen analysis fails to capture the molecular determinants underlying impaired reproductive function. Emerging evidence positions seminal plasma (SP) and extracellular vesicles (EVs) as dynamic regulators of sperm physiology, rather than passive transport components. SP, enriched with proteins, metabolites, hormones, and antioxidants, modulates sperm motility, capacitation, acrosome reaction, and immune tolerance. Complementarily, EVs, including prostasomes, epididymosomes, and testicular vesicles, deliver proteins, lipids, and small RNAs that remodel sperm membranes, protect against oxidative insults, and influence fertilization success. A critical dimension of the SP-EV axis is its role in balancing oxidative stress (OS) and endocrine signaling. Hormones and metabolic regulators within SP, together with EV-mediated transfer of receptors and regulatory RNAs, further integrate systemic metabolic health with local reproductive outcomes. Dysregulation of these networks, particularly in conditions such as varicocele, obesity, diabetes, and idiopathic infertility, compromises sperm function and reduces assisted reproductive technology (ART) success. This evidence-based review synthesizes current evidence on SP and EVs as ‘molecular gatekeepers’ in male infertility, emphasizing OS regulation, endocrine crosstalk, and their potential as biomarker reservoirs. By integrating proteomic, metabolomic, and transcriptomic insights, the translational opportunities for biomarker-informed diagnostics, prognostication, and therapeutic interventions are highlighted. Full article

Male infertility in dromedary camels lacks objective diagnostic tools. This study evaluated the combined diagnostic value of testicular Doppler ultrasonography and semen biomarkers in 68 infertile (azoospermic, n = 21; oligozoospemic, n = 47) and 9 fertile male camels. All animals underwent a breeding soundness evaluation; computer-assisted semen analysis; color Doppler of the supratesticular artery; and a seminal plasma assessment for semenogelin I (SEM I), semenogelin II (SEM II), extracellular matrix protein 1 (ECM1), and testis-expressed protein 101 (TEX101). Infertile camels showed significantly impaired semen quality (p < 0.001). All four biomarkers were significantly lower in the infertile groups than controls (p = 0.001). Doppler indices indicated impaired testicular perfusion, with higher resistive and pulsatility indices (p = 0.003; p = 0.009) and lower velocity parameters (p < 0.001) in infertile animals. Biomarkers were strongly intercorrelated and negatively correlated with Doppler indices. ECM1 was the only significant predictor of infertility from the regression analysis (p = 0.031). Among the oligozoospemic camels stratified by motility, the >50% motility group had significantly higher SEM I and SEM II concentrations (p < 0.002). Integrating Doppler ultrasonography with biomarker profiling provides complementary diagnostic indicators for male camel infertility. Full article