Zinc levels in seminal plasma and their correlation with male infertility: A systematic review and meta-analysis

Prostatitis and male infertility

Infertility is a pressing reproductive health issue in modern society, with male factors accounting for approximately 50% of all cases. However, most research on male infertility has primarily focused on the testis, often ignoring the critical role of the prostate. As the largest male reproductive gland, the prostate plays a vital role in semen quality. Prostatic fluid, a major component of semen, significantly influences sperm function and overall male fertility. Prostatitis, the most common prostate disorder among men, particularly with advancing age, can severely impair reproductive health. This article aims to explore the fundamental physiological functions of the prostate, the etiology of prostatitis, and its impact on sperm health. It also discusses potential treatment strategies for prostatitis. Through this review, we hope to deepen understanding of the prostate's crucial role in male infertility.

Zinc as a Modulator of Male Fertility: Interplay Between Lipid Metabolism, Oxidative Stress, and Sperm Function

Infertility is a multifaceted and pressing global health challenge, with male reproductive impairment playing a significant role in its overall burden. Zinc (Zn), a biologically indispensable trace element, is fundamental to spermatogenesis and overall male reproductive function. This narrative review explores the following aspects: (1) the mechanistic function of Zn in spermatogenesis, (2) the impact of oxidative stress on Zn status and male infertility, (3) the interplay between Zn and lipid metabolism in male reproductive physiology, (4) the relationship between Zn concentrations and semen parameters, and (5) the effects of Zn supplementation on sperm quality, alongside relevant institutional recommendations. The molecular pathways underlying Zn deficiency-induced enzymatic dysfunction, oxidative stress, and lipid homeostasis disruption remain partially elucidated, warranting further investigation into their interdependent effects on male infertility. While accumulating evidence suggests that Zn supplementation may have therapeutic potential in male infertility management, guidelines for its clinical application vary considerably across institutions and regions. To establish a clear and evidence-based framework for the function of Zn in male reproductive health, future research should prioritize determining of optimal Zn levels, the mechanistic links between Zn and lipid metabolism, and the long-term clinical outcomes of Zn supplementation in infertile populations.

Biogenic synthesis of N-doped carbon dots from S. cumini seeds for prostate cancer biomarker citrate detection, its live cancer cell imaging

Citrate is a potential biomarker for early stage detection of prostate cancer (PC), its concentration significantly dropped to 2-20 mM in PC patients. Herein, a cheap, simple, and reliable citrate sensor was proposed based on the biogenic synthesis of nitrogen-doped carbon dots (N-CDs) derived from the biowaste of Syzygiumcumini (S. cumini) seeds. The prepared N-CDs were characterized by TEM, FT-IR and spectral studies. The average size of the N-CDs was found to be 2.4 nm, the presence of -OH and -NH2 functional groups on the surface of N-CDs was confirmed by FT-IR analysis. The N-CDs possess the highest emission at 414 nm and cause quenching after reacting with citrate, which is due to the possible hydrogen bonding interactions between the probe and citrate. The probe expressed the lowest limit of detection of 3.5 nM, high selectivity, high interfering ability (1000-fold), provided a stable response at 5 min of reaction time, good biocompatibility, and delivered a contrast bioimage with different concentrations of citrate. The N-CDs were utilized to detect citrate in human urine samples, obtained good recovery results, and validated with the high-performance liquid chromatography method.

Serum and Seminal Plasma Zinc Levels and Immunopositivity of the ZIP6 and ZIP14 Transporters in Men with Normo- and Teratozoospermia

Zinc plays a crucial role in spermatogenesis, sperm function, and fertilisation. Zinc homeostasis is regulated by ZIP and ZnT transporter proteins, which mediate Zn2+ influx and efflux across sperm cell membranes. This study analysed total Zn concentration in seminal plasma and serum of 10 normozoospermic and 32 teratozoospermic men involved in the process of infertility treatment, using inductively coupled plasma mass spectrometry. In addition, the expression of Zn transporters ZIP6 and ZIP14 in the sperm of two normozoospermic and two teratozoospermic men was analysed using immunofluorescence. Applying Student's t test and the Mann-Whitney U test, we found no significant differences in Zn concentrations in seminal plasma and serum between groups. ZIP6 was mainly localised in the sperm head, with slightly higher immunopositivity in normozoospermic than teratozoospermic samples, but there was no statistically significant difference between the groups. ZIP14 was mainly found in the sperm head, and some teratozoospermic samples showed immunopositivity in the tail, although there were no significant differences in ZIP14 immunopositivity between normozoospermic and teratozoospermic samples. The results suggest that Zn concentrations in seminal plasma and serum, and the expression of ZIP6 and ZIP14, do not differ in normo- and teratozospermic samples, and emphasise the complex interplay of factors underlying male fertility.

Association Between Zinc Levels and the Impact of Its Deficiency on Idiopathic Male Infertility: An Up-to-Date Review

BACKGROUND

Zinc (Zn) is an essential metal that plays a critical role in normal testicular development, spermatogenesis, prevention of sperm degradation, and overall male fertility. This review aims to offer a comprehensive and current overview of seminal plasma Zn levels in fertile men worldwide. It also aims to compare Zn levels in seminal plasma and blood (serum/plasma) between infertile men (cases) and fertile men (controls), examine the impact of Zn on sperm quality and the reproductive hormone, and highlight the effects of Zn supplementation therapy in male infertility.

METHODS

To achieve these goals, peer-reviewed studies from 2000 to 2024 were interrogated with regard to strict inclusion/exclusion criteria and were then thoroughly reviewed and analyzed.

RESULTS

Our findings indicate that maintaining optimal seminal plasma Zn levels is crucial, as low Zn levels are linked to impaired spermatogenesis and male infertility, while high Zn levels can cause oxidative stress and other changes that contribute to infertility. Seminal plasma Zn levels from 100 to 200 mg/L among fertile men worldwide can be roughly considered safe. Comparative analysis showed that a greater number of studies reported lower levels of seminal Zn in cases than in controls. Research into the impact of Zn levels in seminal plasma has shown that, although the results are not yet conclusive, altered (non-normal) Zn levels could influence semen parameters-particularly motility, morphology, and sperm count-and the level of the reproductive hormone, testosterone. Zinc-deficient infertile men could benefit from supplement therapy.

CONCLUSIONS

Assessment of seminal plasma Zn levels in infertile men could provide valuable information and aid in diagnosis and treatment planning.

Understanding the Crucial Role of Seminal Plasma Exosomes in Bull Fertility: A Review

Bull fertility is a multi-factorial trait and is affected by many factors, such as nutrition, genetics, and epigenetics. Superior quality male germplasm with high genetic merit helps to improve the livestock production trait. To achieve the target of livestock production, the availability of superior male germplasm is a great concern. In developing countries, there is a gap between the highly fertile frozen semen doses produced and the highly fertile frozen semen doses required. Improving the quality of existing low-fertile semen from high genetic merit bulls seems to play a promising role in filling this gap. Seminal exosomes are extracellular vesicles secreted by the epithelial cells of the testis, epididymis, and accessory sex glands such as the prostate gland. They contain a cargo of bioactive molecules such as proteins, nucleic acids and various metabolites. These molecules are transferred to the spermatozoa during its maturation and help in sperm capacitation, maturation, acrosome reaction, and fertilisation. Studies reveal that seminal exosomes help to improve the sperm functionality of low-quality sperm. Identification of the molecular profile of exosomes of bulls with proven fertility and their addition in an extender containing low-fertile semen may help to ameliorate the sperm quality of low-fertile semen, which may eventually aid in generating quantities of highly fertile ejaculates.

Zinc as a Possible Critical Element to Prevent Harmful Effects of COVID-19 on Testicular Function: a Narrative Review

Research into innovative non-pharmacological therapeutic routes via the utilization of natural elements like zinc (Zn) has been motivated by the discovery of new severe acute respiratory syndrome-related coronavirus 2 (SARS-COV2) variants and the ineffectiveness of certain vaccination treatments during COVID-19 pandemic. In addition, research on SARS-COV-2's viral cellular entry and infection mechanism has shown that it may seriously harm reproductive system cells and impair testicular function in young men and adolescents, which may lead to male infertility over time. In this context, we conducted a narrative review to give an overview of the data pertaining to Zn's critical role in testicular tissue, the therapeutic use of such micronutrients to enhance male fertility, as well as in the potential mitigation of COVID-19, with the ultimate goal of elucidating the hypothesis of the potential use of Zn supplements to prevent the possible harmful effects of SARS-COV2 infection on testis physiological function, and subsequently, on male fertility.

The Effect of Dietary Organic Copper and Zinc Trace Minerals on some Yield and Mineral Levels and Histological Structure of Testes

This study aims to investigate the effects of providing Cu and Zn minerals with an organic structure reduced by 25% compared to the recommended (NRC) inorganic value on parameters such as the age at which lambs achieve 50% sperm motility yield, some developmental parameters, testis histology, as well as serum, wool, and fecal mineral levels in lambs. The study involved 12 male lambs in the T1 group (organic minerals) and 11 in the T2 group (inorganic minerals) of the Kıvırcık breed. Lambs received minerals from mothers during the last month of fetal period and suckling, continuing individual feeding post-weaning. During individual feeding, T1 received 5.25 mg/kg DM copper-chelate and 15.0 mg/kg DM zinc-chelate, while T2 received 7 mg/kg DM copper-sulfate and 20 mg/kg DM zinc-sulfate. The mothers received identical mineral amounts in the last month of pregnancy and lactation. The ewes birthed offspring solely for the supply of experimental groups. Lambs, averaging about 18.5 kg, underwent bi-weekly electroejaculation, concluding the trial for those with 50% semen motility. Statistical analyses were carried out using the GLM method. No differences were observed between groups in the average age at which lambs achieve 50% sperm motility, live weight, scrotum, and testicular measurements at this age (P > 0.05). Histological analyses revealed no difference in tubule area between T1 and T2 groups (P > 0.05), but tubular epithelium height was greater in T1 (P < 0.01). End-of-trial serum copper, as well as weaning day and end-of-trial serum and fleece zinc mean values, did not differ between groups (P > 0.05). However, T1 had higher mean values for serum Cu on the weaning day (P < 0.01), fleece copper on the weaning day (P < 0.05) and at the end of the trial (P < 0.001). Additionally, the T1 group exhibited lower mean levels of fecal copper (P < 0.05) and fecal zinc (P < 0.001). In conclusion, despite organic copper and zinc levels being 25% lower in the examined parameters, comparable or improved results were achieved with inorganic copper and zinc.

Immunoregulation and male reproductive function: Impacts and mechanistic insights into inflammation

This paper investigates the complex relationship between the immune system and male reproductive processes, emphasizing how chronic inflammation can adversely affect male reproductive health. The immune system plays a dual role; it protects and regulates reproductive organs and spermatogenesis while maintaining reproductive health through immune privilege in the testes and the activities of various immune cells and cytokines. However, when chronic inflammation persists or intensifies, it can disrupt this balance, leading to immune attacks on reproductive tissues and resulting in infertility.This study provides a detailed analysis of how chronic inflammation can impair sperm production, sperm quality, and the secretion of gonadal hormones both directly and indirectly. It also delves into the critical roles of testicular immune privilege, various immune cells, and cytokines in sustaining reproductive health and examines the impacts of infections, autoimmune diseases, and environmental factors on male fertility.

Biochemical and Pharmacological Assessments of Tramadol Abuse on Human Male Fertility: Relation to Seminal Plasma 8-Hydroxyguanosine and Zinc

Tramadol is a pain killing drug highly used worldwide. There is a knowledge gap for fertility consequences of analgesic addiction in men. In this observational study, we investigated the hazards of tramadol abuse on human male reproductive function. A total of 30 tramadol addicts and 30 healthy controls have participated in the study. History and clinical examination of the included subjects were performed. Biochemical and molecular assays were measured in all participants include serum reproductive hormones (calculated free testosterone, FSH, LH, prolactin and estradiol) using ELISA techniques, semen analysis, seminal plasma zinc and selenium assays using colorimetric kits, seminal plasma tramadol concentrations using Gas Chromatography-Mass Spectrometry (GC-MS), and seminal plasma 8-hydroxyguanosine (8-OHG) using high performance liquid chromatography were measured. Tramadol abuse significantly decreased semen parameters quality. Additionally, tramadol abuse significantly decreased testosterone (P = 0.001) and increased prolactin serum levels (P = 0.000). Tramadol abusers showed significantly higher levels of 8-OHG (P < 0.0001) with significantly lower levels of zinc and selenium in their seminal plasma compared with the controls (P < 0.0001, and 0.0002 respectively). Also, tramadol addicts displayed positive correlations between seminal plasma levels of 8-OHG (r = 0.905, P = 0.00) and sperm abnormal forms (r = 0.610, P = 0.000) with seminal plasma tramadol levels. Seminal plasma levels of zinc (r = - 0.815, P = 0.00), sperm motility (r = - 0.484, P = 0.007), and vitality (r = - 0.430, P = 0.018) were negatively correlated with seminal plasma levels of tramadol. Our data suggest that tramadol abuse may impair male fertility by increasing oxidative damage of sperms and reducing testosterone and the antioxidants trace elements in testicular tissues.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12291-023-01141-4.

Contribution of the seminal microbiome to paternal programming

The field of Developmental Origins of Health and Disease has primarily focused on maternal programming of offspring health. However, emerging evidence suggests that paternal factors, including the seminal microbiome, could potentially play important roles in shaping the developmental trajectory and long-term offspring health outcomes. Historically, the microbes present in the semen were regarded as inherently pathogenic agents. However, this dogma has recently been challenged by the discovery of a diverse commensal microbial community within the semen of healthy males. In addition, recent studies suggest that the transmission of semen-associated microbes into the female reproductive tract during mating has potentials to not only influence female fertility and embryo development but could also contribute to paternal programming in the offspring. In this review, we summarize the current knowledge on the seminal microbiota in both humans and animals followed by discussing their potential involvement in paternal programming of offspring health. We also propose and discuss potential mechanisms through which paternal influences are transmitted to offspring via the seminal microbiome. Overall, this review provides insights into the seminal microbiome-based paternal programing, which will expand our understanding of the potential paternal programming mechanisms which are currently focused primarily on the epigenetic modifications, oxidative stresses, and cytokines.

Understanding seminal plasma in male infertility: emerging markers and their implications

Infertility affects a significant proportion of the reproductive-aged population, with male-associated factors contributing to over half of the cases. However, current diagnostic tools have limitations, leading to an underestimation of the true prevalence of male infertility. While traditional semen parameters provide some insights, they fail to determine the true fertility potential in a substantial number of instances. Therefore, it is crucial to investigate additional molecular targets responsible for male infertility to improve understanding and identification of such cases. Seminal plasma, the main carrier of molecules derived from male reproductive glands, plays a crucial role in reproduction. Amongst its multifarious functions, it regulates processes such as sperm capacitation, sperm protection and maturation, and even interaction with the egg's zona pellucida. Seminal plasma offers a non-invasive sample for urogenital diagnostics and has shown promise in identifying biomarkers associated with male reproductive disorders. This review aims to provide an updated and comprehensive overview of seminal plasma in the diagnosis of male infertility, exploring its composition, function, methods used for analysis, and the application of emerging markers. Apart from the application, the potential challenges of seminal plasma analysis such as standardisation, marker interpretation and confounding factors have also been addressed. Moreover, we have also explored future avenues for enhancing its utility and its role in improving diagnostic strategies. Through comprehensive exploration of seminal plasma's diagnostic potential, the present analysis seeks to advance the understanding of male infertility and its effective management.

Leukocytospermia and/or Bacteriospermia: Impact on Male Infertility

Infertility is a globally underestimated public health concern affecting almost 190 million people, i.e., about 17.5% of people during their lifetime, while the prevalence of male factor infertility is about 7%. Among numerous other causes, the prevalence of male genital tract infections reportedly ranges between 10% and 35%. Leukocytospermia is found in 30% of infertile men and up to 20% in fertile men. Bacterial infections cause an inflammatory response attracting leukocytes, which produce reactive oxygen species (ROS) and release cytokines, both of which can cause damage to sperm, rendering them dysfunctional. Although leukocytospermia and bacteriospermia are both clinical conditions that can negatively affect male fertility, there is still debate about their impact on assisted reproduction outcomes and management. According to World Health Organization (WHO) guidelines, leukocytes should be determined by means of the Endtz test or with monoclonal antibodies against CD15, CD68 or CD22. The cut-off value proposed by the WHO is 1 × 106 peroxidase-positive cells/mL. For bacteria, Gram staining and semen culture are regarded as the "gold standard", while modern techniques such as PCR and next-generation sequencing (NGS) are allowing clinicians to detect a wider range of pathogens. Whereas the WHO manual does not specify a specific value as a cut-off for bacterial contamination, several studies consider semen samples with more than 103 colony-forming units (cfu)/mL as bacteriospermic. The pathogenic mechanisms leading to sperm dysfunction include direct interaction of bacteria with the male germ cells, bacterial release of spermatotoxic substances, induction of pro-inflammatory cytokines and ROS, all of which lead to oxidative stress. Clinically, bacterial infections, including "silent" infections, are treatable, with antibiotics being the treatment of choice. Yet, non-steroidal antiphlogistics or antioxidants should also be considered to alleviate inflammatory lesions and improve semen quality. In an assisted reproduction set up, sperm separation techniques significantly reduce the bacterial load in the semen. Nonetheless, contamination of the semen sample with skin commensals should be prevented by applying relevant hygiene techniques. In patients where leukocytospermia is detected, the causes (e.g. infection, inflammation, varicocele, smoking, etc.) of the leukocyte infiltration have to be identified and addressed with antibiotics, anti-inflammatories or antioxidants in cases where high oxidative stress levels are detected. However, no specific strategy is available for the management of leukocytospermia. Therefore, the relationship between bacteriospermia and leukocytospermia as well as their specific impact on functional sperm parameters and reproductive outcome variables such as fertilization or clinical pregnancy must be further investigated. The aim of this narrative review is to provide an update on the current knowledge on leukocytospermia and bacteriospermia and their impact on male fertility.

Trace and essential elements as vital components to improve the performance of the male reproductive system: Implications in cell signaling pathways

Successful male fertilization requires the main processes such as normal spermatogenesis, sperm capacitation, hyperactivation, and acrosome reaction. The progress of these processes depends on some endogenous and exogenous factors. So, the optimal level of ions and essential and rare elements such as selenium, zinc, copper, iron, manganese, calcium, and so on in various types of cells of the reproductive system could affect conception and male fertility rates. The function of trace elements in the male reproductive system could be exerted through some cellular and molecular processes, such as the management of active oxygen species, involvement in the action of membrane channels, regulation of enzyme activity, regulation of gene expression and hormone levels, and modulation of signaling cascades. In this review, we aim to summarize the available evidence on the role of trace elements in improving male reproductive performance. Also, special attention is paid to the cellular aspects and the involved molecular signaling cascades.

Efficacy and safety of fibrin sealant application in patients undergoing thyroidectomy: a systematic review and meta-analysis

Various studies have focused on the application of fibrin sealants (FS) in thyroid surgery. Utilizing a meta-analysis, this systematic review analyzed the findings of recent randomized controlled trials on the safety and efficacy of FS in patients who underwent thyroidectomy. The Cochrane Library, Web of Science, Embase, PubMed, and Medline databases were searched for relevant studies, without any language restrictions. Seven randomized controlled trials were included in the originally identified 69 studies. Overall, 652 patients received FS during thyroid surgery; their outcomes were compared with those of conventionally treated patients. The primary outcomes were total volume of wound drainage, length of hospitalization, and operative time. Significant differences were observed in the total volume of wound drainage (mean deviation (MD): -29.75, 95% confidence interval (CI): -55.39 to -4.11, P = 0.02), length of hospitalization (MD: -0.84, 95% CI: -1.02 to -0.66, P < 0.00001), and surgery duration (MD: -7.60, 95% CI: -14.75 to -0.45, P = 0.04). Secondary outcomes were seroma and hypoparathyroidism development. The risk of hypoparathyroidism did not differ between the FS and conventional groups (I = 0%, relative risk = 1.31, P = 0.38). Analysis of "seroma formation that required invasive treatment" indicated that FS showed some benefit (I2 = 8%, relative risk 0.44, P = 0.15). Heterogeneity among the different trials limited their conclusions. The meta-analysis showed that although FS use did not significantly reduce seroma or hypoparathyroidism incidence in patients after thyroidectomy, it significantly reduced the total drainage volume, length of hospitalization, and duration of surgery.

The role of oral antioxidants in the improvement of sperm parameters in infertile men

PURPOSE

A variety of pathologic conditions may increase oxidative stress in semen resulting in structural modifications to spermozoa's plasma membrane that interfere with sperm motility, morphology, and count. Antioxidants are currently being marketed to treat male infertility. In semen, antioxidants may decrease oxidative stress and potentially improve sperm parameters. In this narrative, mini-review we evaluated the effectiveness of antioxidants in infertility.

METHODS

This mini-review of the current literature has been carried out through searching of the PubMed and Google scholar databases.

RESULTS AND CONCLUSIONS

The literature review suggests that there is evidence that oral antioxidants such as selenium, carnitine, zinc, coenzymeQ10, vitamins E and C, etc. alone or in combinations, improve sperm count, motility, morphology as well as pregnancy rates in infertile men with idiopathic oligoasthenospermia. Unfortunately, most of these studies are poorly designed, limited by sample size, varying in dosage, differing in primary end points, and most notably lacking live birth data. Importantly, large randomized, well-designed, placebo-controlled trials are needed.

Small noncoding RNAs and sperm nuclear basic proteins reflect the environmental impact on germ cells

BACKGROUND

Molecular techniques can complement conventional spermiogram analyses to provide new information on the fertilizing potential of spermatozoa and to identify early alterations due to environmental pollution.

METHODS

Here, we present a multilevel molecular profiling by small RNA sequencing and sperm nuclear basic protein analysis of male germ cells from 33 healthy young subjects residing in low and high-polluted areas.

RESULTS

Although sperm motility and sperm concentration were comparable between samples from the two sites, those from the high-pollution area had a higher concentration of immature/immune cells, a lower protamine/histone ratio, a reduced ability of sperm nuclear basic proteins to protect DNA from oxidative damage, and an altered copper/zinc ratio in sperm. Sperm levels of 32 microRNAs involved in intraflagellar transport, oxidative stress response, and spermatogenesis were different between the two areas. In parallel, a decrease of Piwi-interacting RNA levels was observed in samples from the high-polluted area.

CONCLUSIONS

This comprehensive analysis provides new insights into pollution-driven epigenetic alterations in sperm not detectable by spermiogram.

Deteriorating Semen Quality: The Role of the Environment

Since the end of the last century, several reports have suggested that semen quality is declining, especially in Western countries. Furthermore, cross-sectional studies using similar protocols have suggested regional differences in semen quality of young and fertile men. Reasons for these regional differences and local adverse trends in semen quality are unknown, but environmental factors are suspected to have a role. Besides adulthood environmental exposures, those occurring during testicular development may also affect semen quality. Longitudinal follow-up studies and mixture risk analyses are needed to study the effect of fetal, childhood, and adult life environment on semen quality.

A RETROSPECTIVE ANALYSIS OF MORBIDITY AND MORTALITY IN THE CAPTIVE LEADBEATER'S POSSUM (GYMNOBELIDEUS LEADBEATERI) POPULATION FROM 1970 TO 2021

The Leadbeater's possum (Gymnobelideus leadbeateri) is a critically endangered nocturnal marsupial with a restricted range in the Central Highlands of Victoria, Australia. There are two genetically distinct populations divided by location: highland and lowland. Lowland possums exist in one remnant swamp forest and entered captivity in 2012 when ∼60 individuals remained. Today, with less than 20 lowland individuals remaining, any information that informs the yet-unsuccessful breeding program is critical. This study encompasses a retrospective analysis of the causes of mortality and significant histological lesions in captive highland and lowland individuals across seven institutions internationally from 1970 to 2021. During this time, 245 possums lived in captivity. Postmortem records exist for 99 animals, including 349 histopathology diagnoses from 80 reports and 264 gross necropsy diagnoses from 78 reports. Diagnoses were assigned into two categories based on the importance to the individual (causing death or morbidity to a single animal [n = 194]), or importance to the wider population (causing death or morbidity to more than one animal or was related to reproduction [n = 155]). Individual animals had multiple diagnoses, which were tallied as individual data points. Renal disease was diagnosed 57 times; the most common finding was chronic nephropathy (43/57). Cardiovascular disease was diagnosed 33 times; atherosclerosis associated with obesity was common (n = 10/33). Both categories suggest causal association with captive husbandry but elicit no comment on the lack of success of the breeding program. Reproductive disease was diagnosed 36 times in 24 animals (14 females and 10 males). In females, 11 cases of uterine inflammation and associated clinical signs were associated with ascending infection or neoplasia. Of the seven lowland male possums with mortality data, five were infertile (azoospermia or testicular atrophy). More investigation into the reproductive health of this population is indicated to understand the lack of success in the current breeding program.

Zinc Improves Semen Parameters in High-Fat Diet-Induced Male Rats by Regulating the Expression of LncRNA in Testis Tissue

This study aimed to identify differentially expressed LncRNAs in testis tissue of male rats induced by high-fat diet and their changes after zinc supplementation, by constructing a high-fat feeding rat model, and then supplemented with zinc, and observed the expression of LncRNA in three groups of normal, high-fat fed, and zinc-intervened rats. Experimental studies show that the semen parameters of male rats with high-fat diet were decreased but recovered after zinc supplementation, and the related LncRNA also changed. Zinc may improve the high-fat diet-induced reduction of semen parameters by changing the expression of related LncRNA.

Seminal biomarkers and their correlations to semen parameters in subfertile men

Research question

To assess the levels of seminal biomarkers fructose, zinc and citrate and their correlations to semen parameters in infertile men.

Design

200 infertile male participants undergoing fertility assessment at Singapore General Hospital (SGH), Singapore were recruited prospectively, from June 2020 to August 2021. Their semen samples were assessed for seminal parameters, biomarker levels of fructose, citrate and zinc, leukocyte concentrations and aerobic cultures. They were also assessed for their smoking habits.

Results

Sperm concentrations were negatively correlated to seminal fructose levels, r = -0.262, P < 0.001. Progressive motility were positively correlated to seminal citrate levels, r = 0.181, P = 0.014. Sperm morphology and total motile sperm count (TMSC) were positively correlated to seminal zinc and citrate levels, P < 0.05. Zinc and citrate levels were significantly reduced in teratozoospermia, asthenoteratozoospermia and oligoasthenoteratozoospermia groups compared to normozoospermia, P < 0.05. The presence of infection was associated with elevated leukocyte concentrations, lower sperm concentration (12.5 vs 55.8 million/mL, P = 0.024) and fructose levels (35.5 vs 49.2 µmol/ejaculate). Heavy smokers compared to light smokers, had lower sperm concentrations (35.3 vs 49.4 million/mL), TMSC (30.9 vs 47.5 million) and zinc levels (4.9 vs 6.7 µmol/ejaculate) and significantly lower citrate levels (52.6 vs 79.2 µmol/ejaculate, P = 0.029).

Conclusions

Higher zinc and citrate levels correlated with better progressive motility, sperm morphology and TMSC. Smoking negatively impacted zinc and citrate levels, thereby affecting sperm quality. In conclusion, the inclusion of biomarkers in basic male work-up assessment would assist in identifying common deficiencies and aid in adequate replacement therapy.

Mechanisms of damage to sperm structure in mice on the zinc-deficient diet

BACKGROUND

Zinc (Zn)is an essential trace element for spermatogenesis and its deficiency causes abnormal spermatogenesis.

OBJECTIVE

The present study was conducted to examine the mechanisms by which Zn-deficient diet impairs sperm morphology and its reversibility.

METHODS

30 SPF grade male Kunming (KM) mice were randomly divided into three groups, 10 mice per group. Zn-normal diet group (ZN group) was given Zn-normal diet（Zn content= 30 mg/kg）for 8 weeks. Zn-deficienct diet group (ZD group) was given Zn-deficienct diet（Zn content< 1 mg/kg）for 8 weeks. Zn-deficient and Zn-normal diet group（ZDN group）was given 4 weeks Zn-deficienct diet followed by 4 weeks Zn-normal diet. After 8 weeks, the overnight fasted mice were sacrificed, and blood and organs were collected for further analysis.

RESULTS

The experimental results showed that Zn-deficienct diet leads to increased abnormal morphology sperm and testicular oxidative stress.The rate of abnormal morphology sperm, chromomycin A3(CMA3), DNA fragmentation index (DFI), malondialdehyde (MDA) were significantly increased, and a-kinase anchor protein 4(AKAP4), dynein axonemal heavy chain 1(DNAH1), sperm associated antigen 6(SPAG6), cilia and flagella associated protein 44(CFAP44), glutathione peroxidase (GSH-PX), superoxide dismutase (SOD), total antioxidant capacity (T-AOC), nuclear factor erythroid 2-related factor (NRF2), NAD(P)H:quinone oxidoreductase 1(NQO1)and heme oxygenase 1(HO1) were significantly decreased in the ZD group mice. While the changes in above indicators caused by Zn-deficient diet were significantly alleviated in the ZDN group.

CONCLUSION

It was concluded that Zn-deficient diet causes abnormal morphology sperm and testicular oxidative stress in male mice. Abnormal morphology sperm caused by Zn-deficient diet are reversible, and Zn-normal diet can alleviate them.

Influence of Seminal Metals on Assisted Reproduction Outcome

Increased levels of metal ions in human seminal fluid have a significant correlation with male fertility. Few publications explain the effect of metals in semen and their influence on assisted reproductive treatments. Semen parameters and the levels of twenty-two metals were measured in the seminal fluid of 102 men attended in a Reproductive Unit. Metals were determined by optical emission spectrophotometry. A statistical relationship was found between spermiogram and iron, which was lower than expected in pathological spermiograms (p = 0.032); zinc (p = 0.066), calcium (p = 0.047), and magnesium (p = 0.048) mean levels were higher in normozoospermics. More days of sexual abstinence correlates with higher seminal zinc (p = 0.001) and magnesium levels (p = 0.002). Lower vanadium values were found to be associated with higher fertilization rates (p = 0.039). Higher values of lead (p = 0.052) and vanadium (p = 0.032) were obtained in patients who did not reach 100% embryo cleavage rate. Aluminium (p = 0.042) and sodium (p = 0.002) were found in lower amounts associated with better blastocyst rates. The implantation rate shows an inverse association with women's age and iron and calcium content, compared to magnesium and sodium which presented a significant direct association with this percentage. A significant direct relationship was found between the positive evolution of pregnancy and the values of zinc (p = 0.004), calcium (p = 0.013), potassium (p = 0.002), and magnesium (p = 0.009). The study confirms that zinc, iron, calcium, sodium, aluminium, magnesium, vanadium, and lead have positive-negative effects on reproduction and support the analysis of metals in semen as a new line of study on male fertility with implications for reproductive outcomes.

Potential Mechanism of Platelet-rich Plasma Treatment on Testicular Problems Related to Diabetes Mellitus

Diabetes mellitus is a condition of continuously increased blood glucose levels that causes hyperglycemia. This condition can result in disorders of various organs including testicular problems. The use of platelet-rich plasma (PRP) which is contained in several growth factors shows its potential in overcoming testicular problems. This literature review study was conducted to identify the potential of PRP in overcoming various testicular problems due to diabetic conditions.

The Addition of Opuntia ficus-indica Ethanolic Extract to a Skimmed Milk-Based Extender Impacts Ram Sperm Quality

Recently, researchers have focused on the use of natural antioxidants to improve semen quality as a key element for successful artificial insemination. In this context, the first aim of this study was to determine the antioxidant activity and composition (minerals, vitamins, and sugars) of Opuntia ficus-indica cladode ethanolic extract (ETHEX). A further purpose of the study was to investigate the effect of ETHEX supplementation on the quality of liquid ram semen extended with skim milk (SM) at 5°C. The antioxidant activity of ETHEX was studied using free radical 1, 1-diphenyl-2-picrylhydrazyl (DPPH•) assay. The mineral composition and the sugar and vitamin contents of ETHEX were determined using an inductively coupled plasma optical emission spectrometry (ICP-OES) and HPLC-DAD-RID analytical instruments. As a second part, semen was collected from five Boujaâd rams with an artificial vagina. The ejaculates with more than 70% motility were pooled, extended with skim milk (SM) extender without (control) or supplemented with 1-8% of ETHEX (37°C; 0.8 × 109 sperm/mL). Sperm quality parameters were assessed at 8, 24, 48, and 72 h. The results showed that ETHEX had a higher antioxidant activity compared to those of ascorbic acid and butylated hydroxytoluene (BHT). Furthermore, ETHEX contains a considerable amount of minerals, vitamins, and sugars. The inclusion of 1 or 2% ETHEX in SM increased the sperm motility, viability, and membrane integrity and decreased the abnormality of spontaneous and catalyzed lipids peroxidation (p < 0.05) up to 72 h. In addition, semen diluted with 1 and 2% ETHEX decreased the level of DNA fragmentation compared to the control group (p < 0.05). In conclusion, the ETHEX could be recommended to improve the quality of liquid ram spermatozoa. However, its effects on artificial insemination should be further studied.

Zinc restores functionality in porcine prepubertal Sertoli cells exposed to subtoxic cadmium concentration via regulating the Nrf2 signaling pathway

INTRODUCTION

Among substances released into the environment by anthropogenic activities, the heavy metal cadmium (Cd) is known to induce severe testicular injury causing male subfertility/infertility. Zinc (Zn) is another heavy metal that, unlike Cd, is physiologically present in the testis, being essential for spermatogenesis. We aimed to examine the possibility that 50 µM ZnCl₂ could counteract the toxic effects induced by Cd in an in vitro model of porcine prepubertal Sertoli cells (SCs) exposed to both subtoxic (5 μM) and toxic (10 μM) concentrations of CdCl₂ for 48 h.

MATERIALS AND METHODS

Apoptosis, cell cycle, and cell functionality were assessed. The gene expression of Nrf2 and its downstream antioxidant enzymes, ERK1/2, and AKT kinase signaling pathways were evaluated.

MATERIALS AND RESULTS

We found that Zn, in co-treatment with subtoxic and toxic Cd concentration, increased the number of metabolically active SCs compared to Cd exposure alone but restored SC functionality only in co-treatment with subtoxic Cd concentration with respect to subtoxic Cd alone. Exposure of Cd disrupted cell cycle in SCs, and Zn co-treatment was not able to counteract this effect. Cd alone induced SC death through apoptosis and necrosis in a dose-dependent manner, and co-treatment with Zn increased the pro-apoptotic effect of Cd. Subtoxic and toxic Cd exposures activated the Nrf2 signaling pathway by increasing gene expression of Nrf2 and its downstream genes (SOD, HO-1, and GSHPx). Zn co-treatment with subtoxic Cd attenuated upregulation on the Nrf2 system, while with toxic Cd, the effect was more erratic. Studying ERK1/2 and AKT pathways as a target, we found that the phosphorylation ratio of p-ERK1/2 and p-AKT was upregulated by both subtoxic and toxic Cd exposure alone and in co-treatment with Zn.

DISCUSSION

Our results suggest that Zn could counteract Cd effects by increasing the number of metabolically active SCs, fully or partially restoring their functionality by modulating Nrf2, ERK1/2, and AKT pathways. Our SC model could be useful to study the effects of early Cd exposure on immature testis, evaluating the possible protective effects of Zn.

Intra and intercellular signals governing sperm maturation

After their production in the testis, spermatozoa do not have the capacity to move progressively and are unable to fertilise an oocyte. They sequentially acquire these abilities following their maturation in the epididymis and their capacitation/hyperactivation in the female reproductive system. As gene transcription is silenced in spermatozoa, extracellular factors released from the epididymal epithelium and from secretory glands allow spermatozoa to acquire bioactive molecules and to undergo intrinsic modifications. These modifications include epigenetic changes and post-translational modifications of endogenous proteins, which are important processes in sperm maturation. This article emphasises the roles played by extracellular factors secreted by the epididymis and accessory glands in the control of sperm intercellular signallings and fertilising abilities.

Histopathologic evaluation of the inflammatory factors and stromal cells in the endometriosis lesions: A case-control study

Background

Endometriosis is a multifaceted gynecological disorder defined as a benign estrogen-dependent chronic inflammatory process in which endometrial glands and stroma-like tissues are located outside the uterine cavity. It affects around 2-10% of all women during their reproductive years.

Objective

This study aimed to evaluate the traffic of mesenchymal stem cells and inflammatory factors toward the lesions.

Materials and Methods

Ten samples of normal endometrium and eutopic endometrium were studied as a control group and 10 ectopic samples were considered as a case group. Hematoxylin and eosin staining was used to evaluate stromal cells and inflammatory cells. Immunohistochemical staining was performed to show the presence of proliferating cell nuclear antigen in the lesions. The cells were digested and cultured in the laboratory to study cell proliferation. The number of cells and vessels were counted with Image J software, and data analysis was performed with Prism software.

Results

Data analysis showed that the number of stromal cells and vessels in ectopic tissue were significantly higher than the control group (p < 0.001). Also, the number of inflammatory cells, including neutrophils, monocytes, lymphocytes, and macrophages, in the ectopic group was much higher than in the control group (p < 0.005).

Conclusion

By expanding the number of blood vessels, blood flow increases, and cell migration to tissues is facilitated. The accumulation of inflammatory cells, especially macrophages, stimulates the growth of stem cells and helps implant cells by creating an inflammatory process.

The role of growth factors in human sperm parameters: A review of in vitro studies

In vitro sperm preparation/incubation and cryopreservation are associated with oxidative stress as the main cause of sperm damage, and different strategies are used to improve sperm quality in in vitro conditions to treat male infertility. Growth factors (GFs) are biological molecules that play different roles in various cellular processes such as growth, proliferation, and differentiation. Many studies have shown that GFs and their receptors are expressed in the male reproductive system. In vitro supplementation of GFs to improve sperm parameters has yielded useful results. There are many studies on the effects of GFs on sperm quality improvement and subsequent assisted reproductive technology results. Hence, this study will review the in vitro results of various GFs including brain-derived neurotrophic factor, nerve growth factor, fibroblast growth factor, insulin-like growth factor I, and vascular endothelial growth factor to improve sperm quality.

Comparison between Macro and Trace Element Concentrations in Human Semen and Blood Serum in Highly Polluted Areas in Italy

Macro and trace elements are important regulators of biological processes, including those ones linked to reproduction. Among them, Ca, Cu, Fe, K, Mg, Mn, Na, Se, and Zn ensure normal spermatic functions. Hence, the aim of this study was to evaluate the concentrations of 26 macro and trace elements (Al, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Li, Mg, Mn, Na, Ni, Pb, Rb, Sb, Se, Sn, Sr, U, V, and Zn) in blood serum and also in semen of healthy young men, homogeneous for age, anthropometric characteristics, and lifestyle, living in three highly polluted areas in Italy. Furthermore, a comparison among three geographical areas was performed to highlight any difference in the investigated parameters and, overall, to speculate any correlations between chemical elements and semen quality. Statistically significant differences (p < 0.05) among the three areas were found for each investigated element, in both semen and serum samples, where inter-area differences were more evident in semen than in blood serum, suggesting human semen as an early environmental marker. Considering the homogeneity of three cohorts, these differences could be due more to environmental conditions in the recruiting areas, suggesting that variations in those involved in reproductive-associated pathways can have an impact on male fertility. Nevertheless, more research is needed to evaluate threshold values for sperm dysfunction and male infertility. Actually, the role of different dietary intake and environmental exposure underlying the observed differences in the recruiting areas is under further investigation for the same cohort.

Environmental metal exposure, seminal plasma metabolome and semen quality: Evidence from Chinese reproductive-aged men

Environmental metal exposure has been associated with decreasing semen quality, but the effects of multiple metal exposure on seminal plasma metabolome remain obscure. In this study, semen and repeated urine samples from 551 volunteers were collected in Wuhan City. Heavy metals and trace elements were measured using inductively coupled plasma mass spectrometer, and seminal plasma metabolomes were acquired using liquid chromatography coupled with high-resolution mass spectrometry. Weighted gene co-expression network analysis showed more than half of the seminal plasma metals were associated with specific metabolite modules, whereas only a few urine metals presented weak associations, indicating that seminal plasma may be an ideal biological sample for male reproductive biomarker discovery and exposure risk assessment. Seminal plasma zinc (Zn) and selenium (Se) concentrations were significantly associated with 22 metabolites (e.g., glycerophospholipids, acyl-carnitines and amino acid derivatives). Among these metabolites, acyl-carnitines were positively associated with semen quality and sperm concentration. Moreover, acyl-carnitines were associated with both Zn and Se exposure, indicating the potential role of carnitine pathway in their toxicity mechanism. Our findings suggest that seminal plasma metabolome connects Zn and Se exposure and sperm concentrations in Chinese men of reproductive age.

An Overview of Essential Microelements and Common Metallic Nanoparticles and Their Effects on Male Fertility

Numerous factors affect reproduction, including stress, diet, obesity, the use of stimulants, or exposure to toxins, along with heavy elements (lead, silver, cadmium, uranium, vanadium, mercury, arsenic). Metals, like other xenotoxins, can cause infertility through, e.g., impairment of endocrine function and gametogenesis or excess production of reactive oxygen species (ROS). The advancement of nanotechnology has created another hazard to human safety through exposure to metals in the form of nanomaterials (NMs). Nanoparticles (NPs) exhibit a specific ability to penetrate cell membranes and biological barriers in the human body. These ultra-fine particles (<100 nm) can enter the human body through the respiratory tract, food, skin, injection, or implantation. Once absorbed, NPs are transported to various organs through the blood or lymph. Absorbed NPs, thanks to ultrahigh reactivity compared to bulk materials in microscale size, disrupt the homeostasis of the body as a result of interaction with biological molecules such as DNA, lipids, and proteins; interfering with the functioning of cells, organs, and physiological systems; and leading to severe pathological dysfunctions. Over the past decades, much research has been performed on the reproductive effects of essential trace elements. The research hypothesis that disturbances in the metabolism of trace elements are one of the many causes of infertility has been unquestionably confirmed. This review examines the complex reproductive risks for men regarding the exposure to potentially harmless xenobiotics based on a series of 298 articles over the past 30 years. The research was conducted using PubMed, Web of Science, and Scopus databases searching for papers devoted to in vivo and in vitro studies related to the influence of essential elements (iron, selenium, manganese, cobalt, zinc, copper, and molybdenum) and widely used metallic NPs on male reproduction potential.

Oxidative Stress Markers and Sperm DNA Fragmentation in Men Recovered from COVID-19

SARS-CoV-2 negatively affects semen characteristics, impairs various biochemical processes in seminal fluid and within spermatogenic cells ultimately leading to male fertility decline. However, the distinct mechanisms, in particular, the role of oxidative stress on the consequences of coronavirus infection, have not been well investigated, which is the purpose of the present study. The standard semen parameters, its pro- and antioxidant system state, as well as the level of sperm DNA fragmentation, were assessed in 17 semen samples of men five months after the coronavirus infection and in 22 age-matched control patients. We determined that the DNA fragmentation rate negatively correlated with the period after coronavirus recovery, as well as seminal fluid superoxide dismutase activity and uric acid level. It was demonstrated that COVID-19 is not always associated with increased DNA fragmentation, allowing them to be considered as two independent factors. Thus, the most significant changes were noted in the samples of men after COVID-19 and abnormal TUNEL results: increased round cell number, decreased seminal fluid's nitrotyrosine level, and total antioxidant capacity and Zn, as well as an increased 8-hydroxy-2'-deoxyguanosine level within spermatozoa. The data obtained indicate that increased DNA fragmentation and diminished semen quality in men can be the result of an imbalance in semen pro- and antioxidant components after COVID-19.

Nonpharmacological Interventions for the Management of Testosterone and Sperm Parameters: A Scoping Review

PURPOSE

Testosterone replacement and associated pharmacologic agents are effective strategies to treat male hypogonadism; however, nutraceutical agents and lifestyle modification approaches have gained medical interest. The purpose of this scoping review is to highlight the evidence (or lack thereof) of nutraceuticals and lifestyle modification approaches in the management of testosterone levels and sperm parameters.

METHODS

A scoping review of nonpharmacologic interventions (supplements, herbal medicines, diets, sleep, and exercise) with the potential to improve male health was undertaken to elucidate changes in testosterone levels and sperm parameters in men with hypogonadism or infertility compared with healthy patients.

FINDINGS

A multitude of nutraceuticals and functional nutrients are purported to stimulate testosterone production; however, only a select few have had promising results, such as zinc, vitamin D (in case of hypovitaminosis D), l-arginine, mucuna, and ashwagandha, based on well-controlled randomized clinical trials of men with low testosterone levels and related problems. Except for l-arginine, these natural agents, as well as tribulus and ω3 fatty acids, can improve some degree of sperm parameters in infertile men. Before implementing these nutraceutical agents, adequate sleep, exercise, and weight loss in patients with obesity are imperative. The effects of nonpharmacologic interventions on testosterone levels are modest and hence do not directly translate into clinical benefits. Correspondingly, androgen receptor content, but not endogenous androgens, has been regarded as the principal factor in muscle hypertrophy.

IMPLICATIONS

A limited number of supplements and herbal medicines can be considered as adjunctive approaches in the management of testosterone levels and sperm parameters, primarily in men with low testosterone levels and infertility, whereas most nonpharmacologic supplements appear to lack evidence. Although proper physical exercise, sleep, and diet are indisputable approaches because of the general benefits to health, the use of nutraceuticals, if considered, must be personalized by physicians and/or registered dietitians.

Zinc-Enriched Yeast May Improve Spermatogenesis by Regulating Steroid Production and Antioxidant Levels in Mice

Zinc (Zn) is an essential nutrient for the human body. This nutrient is involved in numerous physiological functions and plays an important role in spermatogenesis. Zn-enriched yeast (ZnY) is considered a Zn supplement with high bioavailability and is widely used as a functional food. However, the effect of ZnY on male reproductive function remains unclear. This study aimed to investigate the beneficial effects of ZnY on the treatment of male spermatogenesis disorders. The spermatogenic dysfunctional mice were established by using cyclophosphamide (CP). CP was administered in saline at a dose of 50 mg/kg bw/day for 5 days by intraperitoneal injection (i.p.). Then, ZnY was orally supplemented at the dose levels of 2, 4, and 8 mg Zn/kg bw/day for 30 days. CP significantly decreased the sperm density and viability, testicular marker enzymes, serum testosterone, follicular stimulating hormone (FSH), and luteinizing hormone (LH). ZnY supplementation significantly improved these sperm parameters and hormone levels. Additionally, ZnY decreased the CP-induced lipid peroxidation and increased the glutathione levels. Moreover, ZnY increased the gene expression of anti-apoptotic proteins and steroid synthetase in mouse testes. The low-dose ZnY supplementation has a better effect on improving spermatogenesis, while the other two groups are less beneficial roles possibly due to excessive Zn intake. The present results suggest that appropriate ZnY can act as an accessory factor to improve steroid production and antioxidant levels in spermatogenic dysfunction mice.

Impacts of cadmium on male fertility: Lessons learnt so far

Cadmium (Cd) is one of the most dangerous heavy metals in the world. Globally, toxicities associated with cadmium and its attendant negative impact on humans and animals cannot be under-estimated. Cd is a heavy metal, and people are exposed to it through contaminated foods and smoking. Cd exerts its deleterious impacts on the testes (male reproductive system) by inducing oxidative stress, spermatogenic cells apoptosis, testicular inflammation, decreasing androgenic and sperm cell functions, disrupting ionic homeostasis, pathways and epigenetic gene regulation, damaging vascular endothelium and blood testes barrier. In association with other industrial by-products, Cd has been incriminated for the recent decline of male fertility rate seen in both man and animals. Understanding the processes involved in Cd-induced testicular toxicity is vital for the innovation of techniques that will help ameliorate infertility in males. In this review, we summed up recent studies on the processes of testicular toxicity and male infertility due to Cd exposure. Also, the usage of different compounds including phytochemicals, and plant extracts to manage Cd reprotoxicity will be reviewed.

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.

Effect of Paternal Diet on Spermatogenesis and Offspring Health: Focus on Epigenetics and Interventions with Food Bioactive Compounds

Infertility is a growing public health problem. Consumption of antioxidant bioactive food compounds (BFCs) that include micronutrients and non-nutrients has been highlighted as a potential strategy to protect against oxidative and inflammatory damage in the male reproductive system induced by obesity, alcohol, and toxicants and, thus, improve spermatogenesis and the fertility parameters. Paternal consumption of such dietary compounds could not only benefit the fathers but their offspring as well. Studies in the new field of paternal origins of health and disease show that paternal malnutrition can alter sperm epigenome, and this can alter fetal development and program an increased risk of metabolic diseases and breast cancer in adulthood. BFCs, such as ascorbic acid, α-tocopherol, polyunsaturated fatty acids, trace elements, carnitines, N-acetylcysteine, and coenzyme Q10, have been shown to improve male gametogenesis, modulate epigenetics of germ cells, and the epigenetic signature of the offspring, restoring offspring metabolic health induced by stressors during early life. This indicates that, from a father’s perspective, preconception is a valuable window of opportunity to start potential nutritional interventions with these BFCs to maximize sperm epigenetic integrity and promote adequate fetal growth and development, thus preventing chronic disease in adulthood.

Metabolic Syndrome and Male Fertility: Beyond Heart Consequences of a Complex Cardiometabolic Endocrinopathy

Metabolic syndrome (MetS) is a highly prevalent condition among adult males, affecting up to 41% of men in Europe. It is characterized by the association of obesity, hypertension, and atherogenic dyslipidemia, which lead to premature morbidity and mortality due to cardiovascular disease (CVD). Male infertility is another common condition which accounts for about 50% of cases of couple infertility worldwide. Interestingly, male infertility and MetS shares several risk factors (e.g., smoking, ageing, physical inactivity, and excessive alcohol consumption), leading to reactive oxygen species (ROS) production and increased oxidative stress (OS), and resulting in endothelial dysfunction and altered semen quality. Thus, the present narrative review aims to discuss the pathophysiological mechanisms which link male infertility and MetS and to investigate the latest available evidence on the reproductive consequences of MetS.

Effects of paternal overnutrition and interventions on future generations

In the last two decades, evidence from human and animal studies suggests that paternal obesity around the time of conception can have adverse effects on offspring health through developmental programming. This may make significant contributions to the current epidemic of obesity and related metabolic and reproductive complications like diabetes, cardiovascular disease, and subfertility/infertility. To date, changes in seminal fluid composition, sperm DNA methylation, histone composition, small non-coding RNAs, and sperm DNA damage have been proposed as potential underpinning mechanism to program offspring health. In this review, we discuss current human and rodent evidence on the impact of paternal obesity/overnutrition on offspring health, followed by the proposed mechanisms, with a focus on sperm DNA damage underpinning paternal programming. We also summarize the different intervention strategies implemented to minimize effects of paternal obesity. Upon critical review of literature, we find that obesity-induced altered sperm quality in father is linked with compromised offspring health. Paternal exercise intervention before conception has been shown to improve metabolic health. Further work to explore the mechanisms underlying benefits of paternal exercise on offspring are warranted. Conversion to healthy diets and micronutrient supplementation during pre-conception have shown some positive impacts towards minimizing the impact of paternal obesity on offspring. Pharmacological approaches e.g., metformin are also being applied. Thus, interventions in the obese father may ameliorate the potential detrimental impacts of paternal obesity on offspring.

Parenteral supplementation of Cu, Zn and Mn enhances boars' sperm quality

INTRODUCTION

The trace elements concentrations of blood might play a key role in the trace element concentration of seminal plasma, as well as in the improvement of semen volume and sperm morphology in boars.

OBJECTIVE

To assess the effect of supplementation of Cu, Zn and Mn on their concentrations in blood serum and seminal plasma and sperm quality in boars.

METHODS

Eighteen boars of the Duroc Jersey breed were selected and their blood and semen (54 ejaculates before supplementation) were extracted. Coinciding with the third sampling and after of blood taken, the boars were supplemented subcutaneously with 37.5 mg of Cu, 75 mg of Zn and 37.5 mg of Mn; 40 days after the supplementation the fourth sampling was taken. Cu and Zn concentrations in blood serum and seminal plasma were determined by atomic absorption spectrophotometry, while the sperm pathologies were determined by microscopy and the concentrations of Cu and Zn in blood serum and seminal plasma, and semen pathologies were compared using the t-Student test for paired samples. A simple linear correlation was made between the minerals concentration in seminal plasma with the percentage of spermatozoa with abnormal forms.

RESULTS

Although the concentrations of Zn in blood serum did not show differences between sampling periods (P < 0.05), they were significantly higher (P < 0.01) in the seminal plasma after supplementation as compared to its levels before supplementation. In addition, the concentrations of Cu and Zn in seminal plasma were increased (P < 0.01), and the total spermatic pathologies were reduced; especially those of the head, neck and intermediate part of the tail (P < 0.001). Besides, macrocephaly, double head and broken acrosome were the most common pathologies (P < 0.05). Moreover, parenteral supplementation of Cu, Zn and Mn was a protective factor to the presentation of ejaculates with abnormal sperm percentages higher than 10% (χ2 = 6.1544; P = 0.0131). The prevalence of abnormal shapes of boars' sperm before supplementation was 0.40; after supplementation the answer was 0.05 and the prevalence ratio was 0.13 with a confidence interval of 95% from 0.01 to 0.94. Moreover, Zn concentrations in blood serum were not correlated with those of the seminal plasma (P > 0.05, r = - 0.0353); however, the concentrations of Cu in both fluids were correlated (P < 0.05, r = 0.2254). In addition, the Zn values in the seminal plasma and the percentage of abnormal spermatozoa had a negative and highly significant correlation (P < 0.0001, r = - 0.5628). However, the Cu concentrations in the semen were not significantly correlated with the abnormal sperm forms (P > 0.05, r = 0.0200).

CONCLUSION

From the present study it can be concluded that in boars fed with diets that meeting their requirements in trace minerals according to NRC (2012) [1], parenteral supplementation of 37.5 mg of Cu, 75 mg of Zn and 37.5 mg of Mn increased the Zn concentrations in the seminal plasma and reduced the sperm pathologies, which resulted in an increase of the boars' sperm quality.

Association between Serum Trace Elements Levels, Steroid Concentrations, and Reproductive Disorders in Ewes and Does

This study aimed to investigate the association of different reproductive disorders with the status of serum trace elements and steroid hormones in ewes and goats. This study included 131 barren and 11 fertile (control) ewes and 94 barren and 9 fertile (control) goats. Animals were examined gynecologically for reproductive soundness. The animals were bled, and their serum was harvested and assayed for manganese (Mn), selenium (Se), iron (Fe), zinc (Zn), estrogen (E2), and progesterone (P4) levels. The results showed that genital affections were associated with significant changes in serum Se (P=0.001), Fe (P=0.008), and Zn (P=0.01) levels in ewes, as well as Mn (P=0.01) levels in goats. Ewes and goats with cystic ovaries had higher serum Se, Fe, and Zn levels (P=0.0001) than ewes with uterine affections, ovarian inactivity, and controls. Ovarian inactivity was linked to low Se levels in ewes and low Se and Zn levels in goats (P=0.05). Ewes and goats with estrogen-dominant reproductive disorders had higher Se (P=0.01), Fe (P=0.03), and Zn (P=0.01) compared with the control group. Se (P=0.02) and Zn (P=0.05) were lower in ewes and goats affected with P4-dominant genital disorders compared with the control group. It can be concluded that the reproductive disorders are associated with changes in the level of trace elements in blood of ewes and goats. There is a reciprocal relationship between the levels of estrogen and progesterone with those of the trace elements in serum of ewes and goats.

Zinc-binding proteins in stallion seminal plasma as potential sperm function regulators

Sperm functions may be influenced by seminal plasma (SP) proteins with affinity to zinc ions. The aim of the study was to isolate and characterise zinc-binding proteins (ZnBPs) from stallion SP using proteomic tools. Zinc-binding proteins were isolated from the SP of eight stallions by zinc-affinity chromatography. They were analysed in the SDS-PAGE system, and peptide extracts were prepared. Samples of ZnBPs isolated from stallion SP were injected onto the nLC-1000 nanoflow HPLC system coupled via a nano-electrospray ion source to the Orbitrap Elite FTMS mass spectrometer (Thermo Fisher Scientific). Raw MS data were analysed using MaxQuant software with label-free quantification (LFQ). Protein sequences were obtained from the UniProt database. Forty-seven proteins in ZnBPs were annotated in a gene ontology (GO) analysis. The LFQ intensity analysis of individual proteins revealed that ZnBPs comprised mainly clusterin (CLU, 27%), serin protease inhibitor F1 (SERPINF1, 13%), actin, cytoplasmic 1 (ACTB, 9%), nucleobindin 2 (NUCB2, 8%) and polymeric immunoglobulin receptor (PIGR, 6%). This is the first proteomic study to analyse ZnBPs in stallion SP. The present findings show that ZnBPs in stallion SP could play an important role in the regulation of sperm function.

Toxicological outcome of phthalate exposure on male fertility: Ameliorative impacts of the co-administration of N-acetylcysteine and zinc sulfate in rats

Background

Reports have shown that humans are consistently exposed to environmental toxicants such as phthalate (PHT) during their daily activities. This results in reproductive dysfunction and infertility-related issues as already noted in human and experimental animals. We therefore designed this study to investigate fertility outcome in phthalate-exposed male rats treated with N-acetylcysteine (NAC) and zinc sulfate (ZnSO4) with the view of providing a therapeutic alternative to reproductive toxicity caused by phthalate. The research was done in two phases. In phase 1, thirty-five male Wistar rats were randomly assigned to one of five (n = 7) groups given the following treatments for 21 days: group A was given distilled water as a control, while groups B, C, D, and E were given phthalate (750 mg/kg/day). Animals in groups C to E were also given ZnSO4 (0.5 mg/kg/day), N-acetylcysteine (100 mg/kg/day), and ZnSO4 (0.5 mg/kg/day) + N-acetylcysteine (100 mg/kg/day) in addition to phthalate. In phase 2, animals from groups in phase 1 were mated with females for fecundity testing.

Results

The result shows alteration in testicular and epididymis weight and testis/epididymis ratio, semen parameters, sperm capacitation and acrosome reaction, sperm DNA, serum Zn and Mg, testicular mitochondria apoptosis mechanisms (TNF-α and BCL-2), and testicular Ca2+-ATPase as well as fecundity outcome in the phthalate-treated group. However, ZnSO4 and NAC successfully ameliorated the deleterious effects of phthalate on semen parameters, sperm capacitation and acrosome reaction, serum electrolyte and mitochondria apoptosis mechanisms, and testicular electrogenic Ca2+-ATPase in phthalate-induced male rats with a better outcome in the combined therapy. Pregnancy outcome and litter sizes were also higher in the combined therapy when also compared with the phthalate-treated groups.

Conclusion

According to the result, ZnSO4 and NAC increased fertility outcome in phthalate-treated male rats through enhancement of testicular BCL-2, serum electrolyte, testicular Ca2+ATPase pumps, and cytoprotection.

Zinc Intakes and Health Outcomes: An Umbrella Review

It is widely accepted that the zinc element is crucial in human beings. Zinc has gained more attention during the COVID-19 pandemic due to its utilization for the treatment and prevention of respiratory tract infections. However, some studies also pointed out that zinc intake might cause unwanted side effects and even be dangerous when overdosed. To reveal the relationship between zinc intake and health outcomes, we performed an umbrella review from human studies. In total, the umbrella review included 43 articles and identified 11 outcomes for dietary zinc intake and 86 outcomes for supplementary zinc intake. Dietary zinc intake in the highest dose would decrease the risk of overall and specific digestive tract cancers, depression, and type 2 diabetes mellitus (T2DM) in adults. Supplementary zinc consumption in adults was linked to an improvement of depression, antioxidant capacity and sperm quality, higher serum zinc concentration, and lower concentration of inflammatory markers. Zinc supplementation in children would reduce the incidence of diarrhea and pneumonia, improve zinc deficiency and boost growth. However, zinc might not decrease all-cause mortality in adults or the in-hospital mortality of COVID-19. And better maternal and neonatal outcomes may not derive from pregnant women who consumed higher or lower doses of zinc supplementation (&gt;20 mg/day and &lt;20 mg/day, respectively). Dose-response analyses revealed that a daily 5 mg increment of zinc would lower the risk of colorectal and esophageal cancer, whereas a large dose of zinc supplementation (daily 100 mg) showed no benefit in reducing prostate cancer risk.

Viral Infections and Male Infertility: A Comprehensive Review of the Role of Oxidative Stress

Viral infections have been a part of human existence to date, though viruses have posed a huge threat with various outbreaks lately. These threats are associated with reproductive health challenges, especially male infertility. The prime focus of this review is to highlight the mechanisms associated with viral infection-induced male infertility/subfertility and identify new treatment strategies with the aim to preserve male fertility. The reviewed data showed that viral infections stimulate inflammatory responses, resulting in the release of proinflammatory cytokines, which induces oxidative stress. This oxido-inflammatory cycle could continue in a vicious cycle and threaten male fertility. Existing data from human and experimental studies show that viral infection-induced oxido-inflammatory response results in testicular damage, atrophy of the seminiferous tubules and Sertoli cells, and reduced Leydig cell mass. This is accompanied by reduced circulatory testosterone, impaired spermatogenesis, reduced sperm motility, lipid peroxidation, DNA fragmentation and apoptosis of the sperm cells. Based on the available pieces of evidence, antioxidant therapy, in vivo and in vitro, may be beneficial and protects against the potential risk of male infertility from viral infection. It is, however recommended that more clinical studies be conducted to demonstrate the possible protective roles of antioxidants used as adjuvant therapy in viral infections, and in the in vitro treatment of semen samples for those utilizing semen washing and artificial reproductive techniques.

Ameliorating high-fat diet-induced sperm and testicular oxidative damage by micronutrient-based antioxidant intervention in rats

PURPOSE

Emerging evidence from rodent studies suggests that high-fat-diet (HFD)-induced obesity is characterized by increased oxidative damage in sperm and testis. However, interventions using micronutrient supplementation to mitigate oxidative damage in obesity have not been extensively studied. This study aimed to investigate the effect of an antioxidant-based micronutrient supplement (added folate, vitamin B₆, choline, betaine, and zinc) on sperm and testicular oxidative damage in HFD-fed male Sprague Dawley rats.

METHODS

Rats (3-weeks-old, 12/group) were weaned onto control (C) or HFD (H) or these diets with micronutrient supplement (CS; HS); sperm and testis were harvested at 30.5 weeks. To assess oxidative stress and antioxidant capacity in testis, levels of malondialdehyde (MDA), glutathione (GSH), folate and susceptibility index (SI) of pro-oxidative damage, mRNA expression of Nrf2, NFκB-p65, IL-6, IL-10 and TNF-α, in addition to superoxide-dismutase (SOD), catalase and glutathione-peroxidase (GPx) activities were measured. 8-hydroxy-2-deoxyguanosine (8-OHdG) were assessed in both sperm and testis.

RESULTS

HFD-fed rats had significantly increased 8-OHdG content in sperm and testis, increased testicular SI, decreased testicular weight, SOD and GPx activity compared to control. Strikingly, supplementation of HFD appeared to significantly reduce 8-OHdG in sperm and testis (22% and 24.3%, respectively), reduce testicular SI and MDA content (28% and 40%, respectively), increase testicular weight (24%), SOD and GPX activity (30% and 70%, respectively) and GSH content (19%). Moreover, supplementation had significant impact to increase testicular folate content regardless of diet. Furthermore, an overall effect of supplementation to increase testicular mRNA expression of Nrf2 was observed across groups. Interestingly, testicular SI was positively correlated with sperm and testicular 8-OHdG and MDA content, suggesting a critical role of testicular antioxidant activity to combat oxidative damage in sperm and testis.

CONCLUSION

Our findings suggest that antioxidant-based micronutrient supplement has the potential to interrupt HFD-induced sperm and testicular oxidative damage by improving testicular antioxidant capacity.

The Relationship between Time to Surgery (TTS) and Survival in Breast Cancer: A Systematic Review and Meta-Analysis

Background:

Curative operation is the practical and primary therapy for masses of breast cancers. In contrast, the correlation between the time interval from breast cancer diagnosis to curative surgery and survival is still uncertain.

Methods:

An electronic literature search was conducted on PubMed/Medline and EMBASE (between Jan 2000 and Jan 2020). Primary endpoints were overall survival (OS) or Disease-Free Survival (DFS). The HR with 95% confidence intervals were calculated using a random-effects or fixed-effects model.

Results:

The combined HR for OS was 1. 10 (95% CI 1. 08–1. 11; P=0. 000) by fixed-effects model, no statistically significant heterogeneity was found (P=1. 000; I2=0%), and this difference was statistically significant (Z=11. 99; P=0. 000).

Conclusion:

This meta-analysis showed a significant adverse association between more prolonged time to surgery (TTS) and lower overall survival in patients with breast cancer. It is reasonable to minimize that interval between diagnosis and curative surgery.

Zinc is an intracellular signal during sperm activation in Caenorhabditis elegans

Sperm activation is a rapid and dramatic cell differentiation event that does not involve changes in transcription, and the signaling cascades that mediate this process have not been fully defined. zipt-7.1 encodes a zinc transporter, and zipt-7.1(lf) mutants display sperm-activation defects, leading to the hypothesis that zinc signaling mediates sperm activation in Caenorhabditis elegans. Here, we describe the development of a method for dynamic imaging of labile zinc during sperm activation using the zinc-specific fluorescence probe FluoZin-3 AM and time-lapse confocal imaging. Two phases of dynamic changes in labile zinc levels were observed during sperm activation. Forced zinc entry using the zinc ionophore pyrithione activated sperm in vitro, and it suppressed the defects of zipt-7.1(lf) mutants, indicating that high levels of cytosolic zinc are sufficient for sperm activation. We compared activation by zinc pyrithione to activation by extracellular zinc, the Na+/H+ antiporter monensin and the protease cocktail pronase in multiple mutant backgrounds. These results indicate that the protease pathway does not require zinc signaling, suggesting that zinc signaling is sufficient to activate sperm but is not always necessary.

Prostatic fluid composition and semen quality in dogs with benign prostatic hyperplasia undergoing treatment with osaterone acetate

Benign prostatic hyperplasia (BPH) may alter prostatic fluid biochemical composition causing reduced fertility. Osaterone acetate (OA) is an androgen receptor antagonist marketed for treatment of canine BPH. Little information exists on effects of OA administration on biochemical composition of canine prostatic fluid and its role on fertility. The aim of this research was to study biochemical composition of prostatic fluid and its role on semen quality in dogs with BPH undergoing treatment with OA. Eight intact, 5-11-year-old dogs with benign prostatic hyperplasia were treated orally with OA at a dose of 0.25-0.5 mg/kg once daily for seven days. Prostatic volume, semen evaluation and a biochemical analysis of prostatic fluid were performed on the day before treatment (D0), D60, D120, D180 and D240. A significant reduction (57% and 61%) of prostatic volume was observed at D60 and D120, respectively, and a significant reduction (20%) of normal spermatozoa was observed at D60 coincident with a significant increase of sperm tail defects, which disappeared during the course of the treatment. Prostatic fluid composition did not vary during the OA treatment except for zinc (Zn²⁺ ) with a significant increase at D120 and D180 correlated with the return to normal sperm values. In conclusion, canine Zn²⁺ prostatic fluid concentrations decrease during development of BPH and return to normal during treatment with OA. Zn²⁺ is an important electrolyte for semen quality, suggesting that oral Zn²⁺ supplementation might be considered a treatment to improve semen quality.