Relationship Between Semen IL-6, IL-33 and Malondialdehyde Generation in Human Seminal Plasma and Spermatozoa

Towards the Development of Novel, Point-of-Care Assays for Monitoring Different Forms of Antioxidant Activity: The RoXstaTM System

(1) Background: This study set out to develop a series of simple, novel, rapid methods for assessing different forms of antioxidant activity. (2) Methods: An ABTS platform was used to engineer: (i) an electrochemical post-activation assay to assess free radical scavenging activity; (ii) an electrochemical pre-activation strategy to assesses the suppression of free radical formation; (iii) a horseradish peroxidase-mediated oxidation system to monitor hydrogen peroxide scavenging activity and (iv) a cumene peroxide-hematin system to determine the ability of samples to scavenge the mixture of organic peroxides and peroxyl and alkoxyl radicals generated in the presence of these reagents. Each assay was assessed against a panel of candidate antioxidant compounds to determine their relative activities and specificities. In addition, human semen samples were analyzed to determine how the results of these antioxidant assays correlated with semen quality. (3) Results: All 4 assays revealed dose-dependent antioxidant activity on the part of vitamin C, N-acetyl cysteine, hypotaurine, BSA, melatonin, glutathione, resveratrol and epigallocatechin gallate. The other compounds tested either completely lacked antioxidant activity or were only active in one of the assays. Using unfractionated human semen as an exemplar of biological fluids rich in antioxidants, the outputs from the individual assays were found to reflect different aspects of semen quality. When the data from all 4 assays were combined, accurate predictions were generated reflecting the importance of oxidative stress in defining semen quality as reflected by sperm count, seminal lipid aldehyde content, sperm DNA damage and free radical generation by the sperm mitochondria. (4) Conclusions: The methodologies described in this paper constitute the basis for rapid, point-of-care assessments of oxidative stress.

Infertility, IL-17, IL-33 and Microbiome Cross-Talk: The Extended ARIA-MeDALL Hypothesis

Infertility, defined as the inability to obtain pregnancy after 12 months of regular unprotected sexual intercourse, has increased in prevalence over the past decades, similarly to chronic, allergic, autoimmune, or neurodegenerative diseases. A recent ARIA-MeDALL hypothesis has proposed that all these diseases are linked to dysbiosis and to some cytokines such as interleukin 17 (IL-17) and interleukin 33 (IL-33). Our paper suggests that endometriosis, a leading cause of infertility, is linked to endometrial dysbiosis and two key cytokines, IL-17 and IL-33, which interact with intestinal dysbiosis. Intestinal dysbiosis contributes to elevated estrogen levels, a primary factor in endometriosis. Estrogens strongly activate IL-17 and IL-33, supporting the existence of a gut-endometrial axis as a significant contributor to infertility.

Screening of cytokine expression in human seminal plasma in associations with sperm disorders and markers of oxidative-antioxidant balance

Among the many factors with a proven relation to semen quality and male fertility, the determination of seminal plasma cytokines provides a promising direction for research into the identification of factors connected with male infertility. The interleukins: IL-1α, -1β, -2, -4, -6, -8, -10, -12p40, -12p70, -18, IFNγ, and GM-CSF, total oxidant (TOS) and antioxidant (TAS) status, were simultaneously examined in seminal plasmas and blood sera in terato- (n = 32), asthenoterato- (n = 33), and oligoasthenoteratozoospermic (n = 29) infertile men and in normozoospermic fertile men (n = 20). Our research shows different cytokine composition of the sera and seminal plasmas in all studied groups, along with much higher concentrations of seminal plasma GM-CSF, IFNγ, IL-1α, IL-4, IL-6, and IL-8 and lower IL-18 and TOS in the comparison to their sera levels. The seminal plasma concentrations of GM-CSF, IFNγ, IL-1α, -4, and -6 differ significantly between fertile and infertile as well as between teratozoospermic, asthenoteratozoospermic, and oligoasthenoteratozoospermic groups. The indication of the cause of different concentrations of cytokines in seminal plasmas of infertile men, and their associations with semen parameters and oxidative status, may be a promising direction for the search for new therapeutic targets that would directly affect the cells and tissues of male reproductive organs.

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.

Redox Homeostasis and Nrf2-Regulated Mechanisms Are Relevant to Male Infertility

Infertility represents a significant global health challenge, affecting more than 12% of couples worldwide, and most cases of infertility are caused by male factors. Several pathological pathways are implicated in male infertility. The main mechanisms involved are driven by the loss of reduction-oxidation (redox) homeostasis and the resulting oxidative damage as well as the chronic inflammatory process. Increased or severe oxidative stress leads to sperm plasma membrane and DNA oxidative damage, dysregulated RNA processing, and telomere destruction. The signaling pathways of these molecular events are also regulated by Nuclear factor-E2-related factor 2 (Nrf2). The causes of male infertility, the role of oxidative stress in male infertility and the Keap1-Nrf2 antioxidant pathway are reviewed. This review highlights the regulatory role of Nrf2 in the balance between oxidants and antioxidants as relevant mechanisms to male fertility. Nrf2 is involved in the regulation of spermatogenesis and sperm quality. Establishing a link between Nrf2 signaling pathways and the regulation of male fertility provides the basis for molecular modulation of inflammatory processes, reactive oxygen species generation, and the antioxidant molecular network, including the Nrf2-regulated antioxidant response, to improve male reproductive outcomes.

Involvement of toxic metals and PCBs mixture in the thyroid and male reproductive toxicity: In silico toxicogenomic data mining

Toxicological research is mostly limited to considering the effects of a single substance, even though the real exposure of people is reflected in their daily exposure to many different chemical substances in low-doses. This in silico toxicogenomic study aims to provide evidence for the selected environmental (organo)metals (lead, cadmium, methyl mercury) + polychlorinated biphenyls mixture involvement in the possible alteration of thyroid, and male reproductive system function, and furthermore to predict the possible toxic mechanisms of the environmental cocktail. The Comparative Toxicogenomic Database, GeneMANIA online software, and ToppGene Suite portal were used as the main tools for toxicogenomic data mining and gene ontology analysis. The results show that 35 annotated common genes between selected chemicals and endocrine system diseases can interact on the co-expression level. Our study highlighted the disruption of the cytokines, the cell's response to oxidative stress, and the influence of the transcription factors as the potential core of toxicological mechanisms of the discussed mixture's effects. The connected toxicological effects of the tested mixture were abnormal sperm cells, a disrupted level of testosterone, and thyroid hormones. The core mechanisms of these effects were inflammation, oxidative stress, disruption of androgen receptor signaling, and the alteration of the FOXO3-Keap-1/NRF2-HMOX1-NQO1 pathway signaling most likely controlled by the co-expression of overlapped genes among used chemicals. This in silico research can be used as a potential core for the determination of biomarkers that can be monitored in future further in vitro and in vivo experiments.

Human Sperm as an In Vitro Model to Assess the Efficacy of Antioxidant Supplements during Sperm Handling: A Narrative Review

Spermatozoa are highly differentiated cells that produce reactive oxygen species (ROS) due to aerobic metabolism. Below a certain threshold, ROS are important in signal transduction pathways and cellular physiological processes, whereas ROS overproduction damages spermatozoa. Sperm manipulation and preparation protocols during assisted reproductive procedures-for example, cryopreservation-can result in excessive ROS production, exposing these cells to oxidative damage. Thus, antioxidants are a relevant topic in sperm quality. This narrative review focuses on human spermatozoa as an in vitro model to study which antioxidants can be used to supplement media. The review comprises a brief presentation of the human sperm structure, a general overview of the main items of reduction-oxidation homeostasis and the ambivalent relationship between spermatozoa and ROS. The main body of the paper deals with studies in which human sperm have been used as an in vitro model to test antioxidant compounds, including natural extracts. The presence and the synergic effects of different antioxidant molecules could potentially lead to more effective products in vitro and, in the future, in vivo.

Microbiology and immune mechanisms associated with male infertility

Up to 50% of infertility is caused by the male side. Varicocele, orchitis, prostatitis, oligospermia, asthenospermia, and azoospermia are common causes of impaired male reproductive function and male infertility. In recent years, more and more studies have shown that microorganisms play an increasingly important role in the occurrence of these diseases. This review will discuss the microbiological changes associated with male infertility from the perspective of etiology, and how microorganisms affect the normal function of the male reproductive system through immune mechanisms. Linking male infertility with microbiome and immunomics can help us recognize the immune response under different disease states, providing more targeted immune target therapy for these diseases, and even the possibility of combined immunotherapy and microbial therapy for male infertility.