Seminal Plasma Proteomic Biomarkers of Oxidative Stress

The Association Between the Levels of Oxidative Stress Indicators (MDA, SOD, and GSH) in Seminal Plasma and the Risk of Idiopathic Oligo-asthenotera-tozoospermia: Does Cu or Se Level Alter the Association?

Epidemiological studies on the associations between the levels of oxidative stress (OS) indicators (MDA, SOD, and GSH) in seminal plasma and the risk of idiopathic oligo-asthenotera-tozoospermia (OAT) are still inconsistent. Additionally, whether the associations can be altered by the status of essential trace elements is still unknown. To investigate the relationship between MDA, SOD, and GSH levels in seminal plasma and the risk of idiopathic OAT, and further to examine whether levels of iron (Fe), copper (Cu), and selenium (Se) in seminal plasma can alter the associations. A total of 148 subjects (75 idiopathic OAT cases and 73 controls) were included in this study. Seminal plasma samples from all the participants were measured for levels of MDA, SOD, GSH, Fe, Cu, and Se. Unconditional logistic regression models were used to examine the associations between three oxidative stress indicators and the risk of idiopathic OAT. Bayesian kernel machine regression was performed to determine the joint effects of levels of three OS indicators on the risk of idiopathic OAT. Subgroup analyses were performed to explore whether the above associations can be different when Fe, Cu, and Se were in different levels. The level of MDA in seminal plasma was positively associated with the risk of idiopathic OAT, with adjusted odds ratio (OR) and 95% confidence interval (CI) of 2.38 (1.17, 4.83), and SOD and GSH levels were not associated with the risk of idiopathic OAT. In BKMR analyses, we found a significant positive association between the mixture of MDA, SOD, and GSH levels and the risk of idiopathic OAT at concentrations below the 65th percentile, while a negative association at concentrations above it. In subgroup analysis, a positive association was observed between MDA levels in seminal plasma and the risk of idiopathic OAT in the high-Cu group (adjusted OR = 3.66, 95%CI = 1.16, 11.57), while no significant association was found in the low-Cu group (adjusted OR = 1.43, 95%CI = 0.44, 4.58). Additionally, a negative association was found between GSH levels in seminal plasma and the risk of idiopathic OAT in the high-Se group (adjusted OR = 0.34, 95%CI = 0.11, 0.99), while no significant association was observed in the low-Se group (adjusted OR = 1.96, 95%CI = 0.46, 8.27). The levels of MDA, SOD, and GSH in seminal plasma were associated with the risk of idiopathic OAT, and the levels of Cu and Se in seminal plasma may alter the associations.

Predictive parameters of the efficacy of varicocele repair: a review

ABSTARCT

Varicocele has a prevalence of 15% in the population and represents a primary cause of infertility in 40% of cases and a secondary cause in approximately 80% of cases. It is considered the major correctable cause of male infertility. Despite its high prevalence in the infertile population, a large number of patients with varicocele do not experience reproductive difficulties. For this reason, it is still highly debated which parameters could be used to predict which patients with varicocele will be most likely to benefit from its repair. The main international and European guidelines state that treatment should only be considered in infertile patients with abnormal sperm quality. However, these guidelines do not help physicians to identify which of these patients may benefit from the treatment. Therefore, this narrative review collects the evidence in the literature on the usefulness of some factors as predictors of improvement, highlighting how some of them may be effective in an initial selection of patients to be treated, while others are promising but further studies are needed. Finally, a brief consideration on the possible role of artificial intelligence is proposed.

Cancer risk and male Infertility: Unravelling predictive biomarkers and prognostic indicators

In recent years, there has been a global increase in cases of male infertility. There are about 30 million cases of male infertility worldwide and male reproductive health is showing rapid decline in last few decades. It is now recognized as a potential risk factor for developing certain types of cancer, particularly genitourinary malignancies like testicular and prostate cancer. Male infertility is considered a potential indicator of overall health and an early biomarker for cancer. Cases of unexplained male factor infertility have high levels of oxidative stress and oxidative DNA damage and this induces both denovo germ line mutations and epimutations due to build up of 8-hydroxy 2 deoxygunaosine abase which is highly mutagenic and also induces hypomethylation and genomic instability. Consequently, there is growing evidence to explore the various factors contributing to an increased cancer risk. Currently, the available prognostic and predictive biomarkers associated with semen characteristics and cancer risk are limited but gaining significant attention in clinical research for the diagnosis and treatment of elevated cancer risk in the individual and in offspring. The male germ cell being transcriptionally and translationally inert has a highly truncated repair mechanism and has minimal antioxidants and thus most vulnerable to oxidative injury due to environmental factors and unhealthy lifestyle and social habits. Therefore, advancing our understanding requires a thorough evaluation of the pathophysiologic mechanisms at the DNA, RNA, protein, and metabolite levels to identify key biomarkers that may underlie the pathogenesis of male infertility and associated cancer. Advanced methodologies such as genomics, epigenetics, proteomics, transcriptomics, and metabolomics stand at the forefront of cutting-edge approaches for discovering novel biomarkers, spanning from infertility to associated cancer types. Henceforth, in this review, we aim to assess the role and potential of recently identified predictive and prognostic biomarkers, offering insights into the success of assisted reproductive technologies, causes of azoospermia and idiopathic infertility, the impact of integrated holistic approach and lifestyle modifications, and the monitoring of cancer susceptibility, initiation and progression. Comprehending these biomarkers is crucial for providing comprehensive counselling to infertile men and cancer patients, along with their families.

Oxidative Stress Biomarkers in Male Infertility: Established Methodologies and Future Perspectives

Male fertility can be affected by oxidative stress (OS), which occurs when an imbalance between the production of reactive oxygen species (ROS) and the body's ability to neutralize them arises. OS can damage cells and influence sperm production. High levels of lipid peroxidation have been linked to reduced sperm motility and decreased fertilization ability. This literature review discusses the most commonly used biomarkers to measure sperm damage caused by ROS, such as the high level of OS in seminal plasma as an indicator of imbalance in antioxidant activity. The investigated biomarkers include 8-hydroxy-2-deoxyguanosine acid (8-OHdG), a marker of DNA damage caused by ROS, and F2 isoprostanoids (8-isoprostanes) produced by lipid peroxidation. Furthermore, this review focuses on recent methodologies including the NGS polymorphisms and differentially expressed gene (DEG) analysis, as well as the epigenetic mechanisms linked to ROS during spermatogenesis along with new methodologies developed to evaluate OS biomarkers. Finally, this review addresses a valuable insight into the mechanisms of male infertility provided by these advances and how they have led to new treatment possibilities. Overall, the use of biomarkers to evaluate OS in male infertility has supplied innovative diagnostic and therapeutic approaches, enhancing our understanding of male infertility mechanisms.

Male Reproductive Toxicity of Antifouling Chemicals: Insights into Oxidative Stress-Induced Infertility and Molecular Mechanisms of Zinc Pyrithione (ZPT)

Zinc pyrithione (ZPT), a widely utilized industrial chemical, is recognized for its versatile properties, including antimicrobial, antibacterial, antifungal, and antifouling activities. Despite its widespread use, recent research has shed light on its toxicity, particularly towards the male reproductive system. While investigations into ZPT's impact on male reproduction have been conducted, most of the attention has been directed towards marine organisms. Notably, ZPT has been identified as a catalyst for oxidative stress, contributing to various indicators of male infertility, such as a reduced sperm count, impaired sperm motility, diminished testosterone levels, apoptosis, and degenerative changes in the testicular tissue. Furthermore, discussions surrounding ZPT's effects on DNA and cellular structures have emerged. Despite the abundance of information regarding reproductive toxicity, the molecular mechanisms underlying ZPT's detrimental effects on the male reproductive system remain poorly understood. This review focuses specifically on ZPT, delving into its reported toxicity on male reproduction, while also addressing the broader context by discussing other antifouling chemicals, and emphasizing the need for further exploration into its molecular mechanisms.

Oxidative Stress and Male Infertility: The Protective Role of Antioxidants

Oxidative stress is a significant factor in male infertility, compromising sperm function and overall reproductive health. As male infertility garners increasing attention, effective therapeutic interventions become paramount. This review investigates the therapeutic role of antioxidants in addressing male infertility. A detailed examination was conducted on antioxidants such as vitamin C, E, B12, D, coenzyme Q10, zinc, folic acid, selenium, l-carnitine, l-arginine, inositols, and alpha-lipoic acid. This analysis examines the methodologies, outcomes, and constraints of current clinical studies. Antioxidants show notable potential in counteracting the negative effects of oxidative stress on sperm. Based on the evidence, these antioxidants, individually or synergistically, can enhance sperm health and reproductive outcomes. However, certain limitations in the studies call for careful interpretation. Antioxidants are integral in tackling male infertility attributed to oxidative stress. The current findings underscore their therapeutic value, yet there's a pressing need for deeper, comprehensive research. Future studies should focus on refining dosage guidelines, identifying potential side effects, and discerning the most efficacious antioxidant combinations for male infertility solutions.

Relationship between biochemical parameters and paraoxonase 1 activity of boar seminal plasma and semen quality

The aim of this study was to examine the biochemical components and the parameters of antioxidant protection in the seminal plasma (SP) of boars, as well as their relationship with semen quality parameters. Thirty-six boars were included in the study, whose ejaculates were divided into two groups: Group I (good quality semen, > 70% progressively motile sperm, < 20% spermatozoa with abnormal morphology, n = 16), and Group II (poor quality semen, < 70% progressively motile sperm, > 20% spermatozoa with abnormal morphology, n = 20). Significantly higher concentrations of ionized calcium (iCa), total cholesterol (TC), lactate-dehydrogenase (LDH) activity, as well as significantly higher values ​​of antioxidant protection parameters: thiol groups (-SH), paraoxonase 1 (PON1), and total antioxidant capacity (TAC) ) were found in the good quality semen, while higher phosphorus (P) concentrations and increased alkaline-phosphatase (ALP) activity were found in the semen of poor quality. A negative correlation of total and progressive sperm motility with P and ALP was found in all examined semen samples, while a positive correlation was found with PON1 and TAC. The percentage of fast sperm cells positively correlated with iCa, chlorine (Cl), lactate, LDH and TAC, while a negative correlation was found with P, magnesium (Mg) and the enzyme creatine-kinase (CK). The percentage of immobile sperm positively correlated with P and ALP, and negatively correlated with TC, CK, PON1 and TAC. Elevated values ​​of PON1 and TAC in SP and a positive correlation with sperm motility indicate the possible use of these parameters as sensitive biomarkers of boar semen quality. To the best of our knowledge there are no published data on association between PON1 activity and boar semen quality.

Cessation of chronic delta-9-tetrahydrocannabinol use partially reverses impacts on male fertility and the sperm epigenome in rhesus macaques

OBJECTIVE

To determine whether discontinuation of delta-9-tetrahydrocannabinol (THC) use mitigates THC-associated changes in male reproductive health using a rhesus macaque model of daily THC edible consumption.

DESIGN

Research animal study.

SETTING

Research institute environment.

PATIENT(S)

Adult male rhesus macaques (age, 8-10 years; n = 6).

INTERVENTION(S)

Chronic daily THC edible administration at medically and recreationally relevant contemporary doses followed by cessation of THC use.

MAIN OUTCOME MEASURE(S)

Testicular volume, serum male hormones, semen parameters, sperm deoxyribonucleic acid (DNA) fragmentation, seminal fluid proteomics, and whole genome bisulfite sequencing of sperm DNA.

RESULT(S)

Chronic THC use resulted in significant testicular atrophy, increased gonadotropin levels, decreased serum sex steroid levels, changes in seminal fluid proteome, and increased DNA fragmentation with partial recovery after discontinuation of THC use. For every increase of 1 mg/7 kg/day in THC dosing, there was a significant decrease in the total testicular volume bilaterally by 12.6 cm3 (95% confidence interval [CI], 10.6-14.5), resulting in a 59% decrease in volume. With THC abstinence, the total testicular volume increased to 73% of its original volume. Similarly, with THC exposure, there were significant decreases in the mean total testosterone and estradiol levels and a significant increase in the follicle-stimulating hormone level. With increasing THC dose, there was a significant decrease in the liquid semen ejaculate volume and weight of coagulum; however, no other significant changes in the other semen parameters were noted. After discontinuing THC use, there was a significant increase in the total serum testosterone level by 1.3 ng/mL (95% CI, 0.1-2.4) and estradiol level by 2.9 pg/mL (95% CI, 0.4-5.4), and the follicle-stimulating hormone level significantly decreased by 0.06 ng/mL (95% CI, 0.01-0.11). Seminal fluid proteome analysis revealed differential expression of proteins enriched for processes related to cellular secretion, immune response, and fibrinolysis. Whole genome bisulfite sequencing identified 23,558 CpGs differentially methylated in heavy-THC vs. pre-THC sperm, with partial restoration of methylation after discontinuation of THC use. Genes associated with altered differentially methylated regions were enriched for those involved in the development and function of the nervous system.

CONCLUSION(S)

This is the first study demonstrating that discontinuation of chronic THC use in rhesus macaques partially restores adverse impacts to male reproductive health, THC-associated sperm differentially methylated regions in genes important for development, and expression of proteins important for male fertility.

Unraveling the harmful effect of oxidative stress on male fertility: A mechanistic insight

Male infertility is a widely debated issue that affects males globally. There are several mechanisms involved. Oxidative stress is accepted to be the main contributing factor, with sperm quality and quantity affected by the overproduction of free radicals. Excess reactive oxygen species (ROS) cannot be controlled by the antioxidant system and, thus, potentially impact male fertility and hamper sperm quality parameters. Mitochondria are the driving force of sperm motility; irregularities in their function may lead to apoptosis, alterations to signaling pathway function, and, ultimately, compromised fertility. Moreover, it has been observed that the prevalence of inflammation may arrest sperm function and the production of cytokines triggered by the overproduction of ROS. Further, oxidative stress interacts with seminal plasma proteomes that influence male fertility. Enhanced ROS production disturbs the cellular constituents, particularly DNA, and sperms are unable to impregnate the ovum. Here, we review the latest information to better understand the relationship between oxidative stress and male infertility, the role of mitochondria, the cellular response, inflammation and fertility, and the interaction of seminal plasma proteomes with oxidative stress, as well as highlight the influence of oxidative stress on hormones; collectively, all of these factors are assumed to be important for the regulation of male infertility. This article may help improve our understanding of male infertility and the strategies to prevent it.

Obesity: A Doorway to a Molecular Path Leading to Infertility

The dramatic rise in obesity has recently made it a global health issue. About 1.9 billion were overweight, and 650 million global populations were obese in 2016. Obese women suffer longer conception time, lowered fertility rates, and greater rates of miscarriage. Obesity alters hormones such as adiponectin and leptin, affecting all levels within the hypothalamic-pituitary-gonadal axis. Advanced glycation end products (AGEs) and monocyte chemotactic protein-1 (MCP-1) are inflammatory cytokines that may play an important role in the pathophysiology of ovarian dysfunction in obesity. In obese males, there are altered sperm parameters, reduced testosterone, increased estradiol, hypogonadism, and epigenetic modifications transmitted to offspring. The focus of this article is on the possible adverse effects on reproductive health resulting from obesity and sheds light on different molecular pathways linking obesity with infertility in both female and male subjects. Electronic databases such as Google Scholar, Embase, Science Direct, PubMed, and Google Search Engine were utilized to find obesity and infertility-related papers. The search strategy is detailed in the method section. Even though multiple research work has shown that obesity impacts fertility in both male and female negatively, it is significant to perform extensive research on the molecular mechanisms that link obesity to infertility. This is to find therapeutics that may be developed aiming at these mechanisms to manage and prevent the negative effects of obesity on the reproductive system.

Exploring the Role of Oxidative Stress in Sperm Motility: A Proteomic Network Approach

Significance: Infertility is a major global health problem, with nearly half of the cases being associated with male factors. Although reactive oxygen species (ROS) are crucial for sperm cell normal physiological processes, an imbalance between ROS production and antioxidants can lead to oxidative stress that can impair sperm function. Indeed, high semen ROS levels are reported in 30%-80% of infertile men. Recent Advances: Male oxidative stress infertility is an uprising classification for idiopathic infertility. Proteomic approaches, including quantitative mass spectrometry (MS)-based proteomics, are being utilized to explore the molecular mechanisms associated with oxidative stress in male infertility. Critical Issues: In this review, proteome data were collected from articles available on PubMed centered on MS-based proteomic studies, performed in seminal plasma and sperm cell samples, and enrolling men with impaired semen parameters. The bioinformatic analysis of proteome data with Cytoscape (ClueGO+CluePedia) and STRING tools allowed the identification of the biological processes more prevalent in asthenozoospermia, with focus on the ones related to oxidative stress. Future Directions: The identification of the antioxidant proteins in seminal plasma and sperm cells that can protect sperm cells from oxidative stress is crucial not only for a better understanding of the molecular mechanisms associated with male infertility but specially to guide new therapeutic possibilities. Antioxid. Redox Signal. 37, 501-520.

Seminal Plasma Glycoproteins as Potential Ligands of Lectins Engaged in Immunity Regulation

Environmental pollution, chronic stress, and unhealthy lifestyle are factors that negatively affect reproductive potential. Currently, 15-20% of couples in industrialized countries face the problem of infertility. This growing health and social problem prompts researchers to explore the regulatory mechanisms that may be important for successful fertilization. In recent years, more attention has been paid to male infertility factors, including the impact of seminal plasma components on regulation of the female immune response to allogenic sperm, embryo and fetal antigens. Directing this response to the tolerogenic pathway is crucial to achieve a healthy pregnancy. According to the fetoembryonic defense hypothesis, the regulatory mechanism may be associated with the interaction of lectins and immunomodulatory glycoepitopes. Such interactions may involve lectins of dendritic cells and macrophages, recruited to the cervical region immediately after intercourse. Carbohydrate binding receptors include C type lectins, such as DC-SIGN and MGL, as well as galectins and siglecs among others. In this article we discuss the expression of the possible lectin ligands, highly fucosylated and high mannose structures, which may be recognized by DC-SIGN, glycans of varying degrees of sialylation, which may differ in their interaction with siglecs, as well as T and Tn antigens in O-glycans.

Quercetin ameliorates oxidative stress‑induced cell apoptosis of seminal vesicles via activating Nrf2 in type 1 diabetic rats

It was known that diabetes may affect the male reproductive function by inhibiting the secretion of male accessory glands including seminal vesicles. Increased cell apoptosis induced by oxidative stress is thought to be an important pathological change in the seminal vesicles in diabetic patients. Quercetin is a potent anti-oxidative bioflavonoid. In this study, we explore the effect of quercetin on cell apoptosis of seminal vesicles and its underlying mechanism. The STZ-induced type 1 diabetic rat model was established. Three doses (low, medium and high) of quercetin were administrated to the STZ-induced type 1 diabetic rats for 4 months. Fasting blood glucose, the fructose in seminal plasma, total antioxidant capacity (T-AOC) and malondialdehyde (MDA) in seminal vesicles were determined by colorimetric method. Nuclear transcription factor- Nrf2 was observed by immunofluorescent staining. Biomarkers related to cell apoptosis, such as Bcl-2, Bax and cleaved -Caspase3 were measured by Western blotting and immumohistochemical staining. The body weight and seminal vesicle weight indexes were also determined. The results showed that T-AOC and Nrf2 were decreased, the levels of MDA were increased, the cleaved Caspase-3 was increased and the ratio of Bax to BCL-2 was decreased in seminal vesicles of diabetic rats, along with the severe hyperglycemia. When diabetic rats were treated by quercetin for 4 months, all the indexes were reversed at different degree except the fasting blood glucose. Our results suggested that quercetin could ameliorate oxidative stress‑induced cell apoptosis of seminal vesicles via inhibiting Nrf2 in type 1 diabetic rats, which indicated that quercetin could be used for preventing lesions of seminal vesicles in type 1 diabetes.

Oxidative Stress in Men with Obesity, Metabolic Syndrome and Type 2 Diabetes Mellitus: Mechanisms and Management of Reproductive Dysfunction

Reactive oxygen species (ROS) are critical physiological mediators of cellular function, including male fertility. When ROS exceed antioxidant regulation, oxidative stress occurs which is detrimental to cellular function. Oxidative stress has been found to be a central mediator of obesity, metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM), as well as with male infertility. Human studies have correlated testicular oxidative stress in obese males, and animal studies have further provided insight into potential mechanisms of action. Management of oxidative stress is not well defined. Appropriate nutrition and exercise can be recommended for all diabetic patients, and weight loss for obese patients with MetS and T2DM. Consideration of dietary supplements including micronutrients, antioxidants or medicinal herbs are recommended. Metformin may also offer benefits on testicular oxidative stress and fertility parameters. Significantly more research on causation, mechanisms, clinical assessments and appropriate management of infertility on obesity, MetS and T2DM is still required.

Oxidative Stress in Metabolic and Endocrine Diseases: Basic and Translational Aspects

The aim of this Special Issue is to highlight oxidative stress (OS) as a mechanism underlying a major risk factor for several human diseases [...]

Systemic immune-inflammation index, neutrophil-lymphocyte ratio and platelet-lymphocyte ratio are predictors of sperm presence in microdissection testicular sperm extraction

The aim of this study is to evaluate the value of the haematologic inflammatory parameters in predicting sperm retrieval rates during microdissection testicular sperm extraction (micro-TESE).159 patients diagnosed with non-obstructive azoospermia were included in the study. After excluding the patients that do not fit the inclusion criteria, age, smoking status, body-mass index, serum luteinizing hormone, follicle-stimulating hormone, total testosterone levels and neutrophil, lymphocyte and platelet counts were recorded. Neutrophil-lymphocyte ratio, platelet-lymphocyte ratio and systemic immune-inflammation index were calculated. The primary outcome was defined as the presence of spermatozoa during the procedure and the association between the candidate predictors and primary endpoint were evaluated by logistic regression analysis. Then, a baseline model from age, smoking, body-mass index and hormonal levels was built. Ratios and indexes were included, respectively, and were compared by multivariate analyses. Each of all three parameters was an independent predictor of obtaining spermatozoa during micro-TESE procedure (all p < 0.001). Even though all three parameters were significant, neutrophil-lymphocyte ratio and systemic immune-inflammation index stood out as more powerful than platelet-lymphocyte ratio (p < 0.08, p < 0.08 respectively). Additionally, adding these parameters individually to the baseline model significantly empowered the predictive value (all p < 0.001). Using haematologic inflammatory parameters in the prediction of sperm presence during microdissection testicular sperm extraction may be helpful when consulting the patient with having a better foresight of the procedural outcomes.

Seminal Levels of Omentin-1/ITLN1 in Inflammatory Conditions Related to Male Infertility and Localization in Spermatozoa and Tissues of Male Reproductive System

Purpose

Omentin-1/intelectin (ITLN)1 is an adipocytokine with both anti-inflammatory and anti-oxidative stress properties, and little is known about its role in male reproduction. This study was aimed at exploring the relationships among omentin-1/ITLN1, semen parameters and F₂-isoprostanes (F₂-IsoPs), a maker of oxidative stress, in groups of patients affected by different pathologies. In addition, omentin-1/ITLN1 immunolocalization was assessed in ejaculated spermatozoa and in tissues of male reproductive system.

Patients and Methods

Semen samples of infertile patients with varicocele (n = 27), genitourinary infections (n = 17), idiopathic infertility (n = 15) and fertile men (n = 21) were analyzed following WHO guidelines, and seminal plasma were used to determine omentin-1/ITLN1 by ELISA and F₂-IsoP levels by gas chromatography/negative-ion chemical ionization tandem mass spectrometry. Omentin-1/ITLN1 was localized in human sperm and in the tissue of male reproductive system.

Results

Considering all participants, F₂-IsoP and omentin-1/ITLN1 levels were positively correlated (p = 0.000), and both these indices were negatively correlated with sperm parameters. Infertile patients showed lower sperm parameters than fertile ones; varicocele and infection groups had significantly increased levels of F₂-IsoPs (both p = 0.000) and omentin-1/ITLN1 (p = 0.000 and p = 0.001, respectively). Omentin-1/ITLN1 signal was located as a spot in the connecting piece (in 43.5% of cases midpiece was also labeled) of sperm from fertile men and in cytoplasmic residue and in the entire tail in sperm of patients with varicocele and genitourinary infections. A focal omentin-1/ITLN1 immunolabelling was evident in the basal area of epididymal tubule, and a diffuse signal was present in the seminal vesicle epithelium.

Conclusion

Semen omentin-1/ITLN1 originates from seminal vesicles, its levels increase in inflammatory conditions and are negatively correlated with sperm parameters. For this reason, a sort of protective role of omentin-1/ITLN1 can be postulated, as this adipokine shows anti-inflammatory properties also in many other biological systems.

Fatty Acid Oxidation and Pro-Resolving Lipid Mediators Are Related to Male Infertility

Specialized pro-resolving lipid mediators regulate the resolution of acute inflammation. They are formed by enzymatic oxygenation of polyunsaturated fatty acids and are divided into families including lipoxins, resolvins, protectins, and maresins. Resolvin D1 (RvD1), produced by docosahexaenoic acid, exerts anti-inflammatory and pro-resolving activities. This research aimed to investigate the implication of seminal RvD1 in human infertility. Infertile patients (n° 67) were grouped based on pathological reproductive conditions as idiopathic infertility, varicocele, and leukocytospermia; the fourth group was composed of fertile men (n° 18). Sperm characteristics were evaluated by light microscopy (WHO guidelines) and by transmission electron microscopy (TEM). The seminal levels of RvD1 and F2-isoprostane (F2-IsoPs) were dosed. In twenty men (6 fertile men, 8 with varicocele, 6 with leukocytospermia) seminal phospholipase A2, iron, cholesterol, transferrin, estradiol, ferritin, testosterone, and sperm membrane fatty acids were detected. The results indicated that: (i) RvD1 amount was positively correlated with F2-IsoPs and reduced sperm quality; (ii) RvD1 levels were significantly higher in patients with leukocytospermia, varicocele, and idiopathic infertility compared to fertile men; (iii) RvD1 increased along with other markers of oxidative stress and inflammation as fatty acids content and clinical biomarkers. This study suggests a panel of inflammatory markers and lipid mediators for a diagnosis of inflammatory status and a subsequent appropriate therapeutic approach.

Molecular Mechanisms Underlying the Relationship between Obesity and Male Infertility

In recent decades, the worldwide prevalence of obesity has risen dramatically and is currently estimated to be around 20%. Obesity is linked to an increased risk of comorbidities and premature mortality. Several studies have shown that obesity negatively impacts male fertility through various mechanisms. This review aims to investigate the molecular mechanisms through which obesity impairs male reproduction, including obesity-associated hypogonadism and its effects on spermatogenesis, chronic inflammation, and oxidative stress. Obesity negatively impacts both conventional and biofunctional sperm parameters, and it also induces epigenetic changes that can be transferred to offspring. Moreover, obesity-related diseases are linked to a dysregulation of adipocyte function and micro-environmental inflammatory processes. The dysregulated adipokines significantly influence insulin signaling, and they may also have a detrimental effect on testicular function. Sirtuins can also play an important role in inflammatory and metabolic responses in obese patients. Understanding the molecular mechanisms that are involved in obesity-induced male infertility could increase our ability to identify novel targets for the prevention and treatment of obesity and its related consequences.

Semen analysis: a workflow for an appropriate assessment of the male fertility status

Infertility is a worldwide problem that affects 9-15% of couples of reproductive age. In about half of the cases, it recognizes, alone or in combination, a male cause. In addition to a reproductive problem, male infertility can result from a systemic disease. Consequently, semen analysis, a fundamental test in the diagnosis of male infertility, represents a useful indicator not only of a man's reproductive capacity but also of his health and lifestyle. Given the key role of semen analysis, only accredited laboratories should perform it and experienced clinicians should be called into play in its interpretation. In this article, we have extensively examined how the macroscopic and microscopic parameters of semen analysis, alone or associated with each other, allow clinicians to orient towards specific diagnoses that can be confirmed by further ad hoc tests. On this basis, we also proposed a diagnostic flowchart focused on the results of the semen analysis.

Protein markers of spermatogenesis and their potential use in the management of azoospermia

INTRODUCTION

Azoospermia, absence of sperm in the ejaculate is classified as obstructive (OA) and non-obstructive azoospermia (NOA). In OA, sperm are produced, but due to physical obstruction in the male reproductive tract, they are not released in the ejaculate. NOA, on the other hand, is defined as the absence of sperm in the ejaculate due to testicular dysfunction. In NOA, spermatogenesis is frequently preserved in specific sites, and proteomics studies have been employed in order to identify men with preserved spermatogenesis.

AREAS COVERED

Differential protein expression in patients with male infertility is an indicator of impaired spermatogenesis. Here, we reviewed proteins with a potential role as biomarkers of spermatogenesis that could help in the management of non-obstructive and obstructive azoospermia. The following keywords were used for bibliographic research: seminal plasma, proteomics, male infertility, nonobstructive, obstructive, azoospermia, oligospermia.

EXPERT OPINION

Biopsy is an invasive and potentially harmful technique for detecting spermatogenesis in men with OA and NOA. Seminal plasma proteins are highly promising as biomarkers for spermatogenesis. Current literature presents a number of potential candidate biomarkers for determining preserved spermatogenesis.

Insights and clinical potential of proteomics in understanding spermatogenesis

Introduction: With the worldwide decline on male fertility potential, the importance of the insight of the spermatogenic process has been increasing. In recent years, proteomic methodologies have been applied to seminal fluid of infertile men to search for infertility potential biomarkers. However, to understand the spermatogenic event and to search for treatment to spermatogenic impairment, comparative analysis of testicular proteomics is considered a powerful methodology.Areas covered: Herein, we present a critical overview of the studies addressing proteomic alterations in the development of spermatogenesis during puberty, as well as during the different phases of the spermatogenic event. The comparative studies of the proteomic testicular profile of men with and without spermatogenic impairment are also discussed and key proteins and pathways involved highlighted.Expert opinion: The usage of whole human testicular tissue with its heterogeneous cellular composition makes proteome data interpretation particularly challenging. This may be minimized by controlled experiments involving the collection of testicular tissue and sperm from the same individuals, integrated in a clinically characterized cohort of healthy and infertile men. The analysis of specific subcellular proteomes can add more information to the proteomic puzzle, opening new treatment possibilities for infertile/subfertile men.

The Relationship between Seminal Fluid Hyperviscosity and Oxidative Stress: A Systematic Review

INTRODUCTION

Seminal fluid viscosity is a key parameter to achieve fertilization. Viscosity is more frequently increased in patients with infertility. However, the mechanism by which hyperviscosity causes infertility is still poorly understood. As an increased blood viscosity is associated with diseases caused by oxidative stress, it can be supposed that there is a relationship between seminal fluid viscosity and oxidative stress in male infertility. Therefore, this systematic review aims to investigate the relationship between hyperviscous seminal fluid and oxidative stress.

MATERIALS AND METHODS

We performed a systematic search on the following databases Pubmed, MEDLINE, Cochrane, and Scopus from the earliest available date to 10 January 2021, using Medical Subjects Headings (MeSH) indexes and keywords searches. The study included all the articles that evaluated the relationship between increased seminal fluid viscosity and oxidative stress. Article reviews even though dealing with seminal fluid hyperviscosity were excluded.

RESULTS

5 articles were included in this systematic review. The results demonstrated an important impairment of antioxidant systems and increased oxidative stress in patients with high seminal fluid viscosity.

CONCLUSIONS

These findings suggest that a careful assessment of oxidative stress in patients with hyperviscosity may be very useful in clinical practice. Infertile patients with seminal fluid hyperviscosity could benefit from the treatment with antioxidants to protect sperm cells from oxidative damage and to improve their functional properties.

Exploratory Analysis in the Differences in Blood Serum and Seminal Plasma of Adipose-Tissue Related Peptides in Obese and Non-Obese Men and Their Correlations With Semen Parameters

OBJECTIVES

Evaluating the relationship between circulating metabolic biomarkers and semen parameters in obese, overweight and normal-weight patients.

METHODS

Patients were recruited at the "Andrology and Pathophysiology of Reproduction Unit", in Santa Maria Goretti Hospital. Divided into three groups were 98 participants (obese, overweight and normal-weight patients) according to BMI and were analyzed for three adipokines and six hormone peptides in blood serum and seminal plasma using Luminex assay. Standard semen analysis was performed for ejaculate volume, sperm concentration, total sperm count, motility, morphology and leukocytes.

RESULTS

In all groups of subjects, we observed a higher concentration of blood serum c-peptide, GIP, PAI-1, leptin, ghrelin and GLP-1 in comparison to seminal plasma; differently, higher levels in seminal plasma were observed for insulin and visfatin. In comparison to the non-obese subjects, obese subjects showed a higher blood serum concentration of c-peptide, GLP-1, GIP and leptin and a higher concentration of seminal plasma of GIP and insulin. Total sperm count, progressive motility, motility, and atypical forms directly correlated with PAI-1 and visfatin, whereas GLP-1 directly correlated only with total progressive motility.

CONCLUSION

Obese men showed a different pattern of blood serum and seminal plasma adipokines and hormone peptides concentrations in comparison to normal-weight men. Furthermore, these molecules correlated with functional seminal parameters. Our findings support the option to consider these molecules as new biomarkers and pharmacological targets for a new therapeutic approach in male infertility. However, further studies identifying other potential biomarkers of male infertility with important clinical implication and characterizing their mechanisms of action are mandatory.