Imbalance in seminal fluid MIF indicates male infertility

Microfluidics facilitating the use of small extracellular vesicles in innovative approaches to male infertility

Sperm are transcriptionally and translationally quiescent and, therefore, rely on the seminal plasma microenvironment for function, survival and fertilization of the oocyte in the oviduct. The male reproductive system influences sperm function via the binding and fusion of secreted epididymal (epididymosomes) and prostatic (prostasomes) small extracellular vesicles (S-EVs) that facilitate the transfer of proteins, lipids and nucleic acids to sperm. Seminal plasma S-EVs have important roles in sperm maturation, immune and oxidative stress protection, capacitation, fertilization and endometrial implantation and receptivity. Supplementing asthenozoospermic samples with normospermic-derived S-EVs can improve sperm motility and S-EV microRNAs can be used to predict non-obstructive azoospermia. Thus, S-EV influence on sperm physiology might have both therapeutic and diagnostic potential; however, the isolation of pure populations of S-EVs from bodily fluids with current conventional methods presents a substantial hurdle. Many conventional techniques lack accuracy, effectiveness, and practicality; yet microfluidic technology has the potential to simplify and improve S-EV isolation and detection.

Interaction of sperm cells with the female reproductive tract in cattle: Focus on neutrophil extracellular trap formation

After insemination of cows, either naturally or artificially, the deposition of semen into the vagina or uterus results in an immune reaction which is based on polymorphonuclear neutrophil activity. Sperm must be resistant to immune system actions of the female for an adequate time to allow fertilization to occur. Neutrophils, however, either directly phagocytize sperm through cell-cell attachment or entrap sperm cells in neutrophil extracellular traps (NETs), structures consisting of neutrophil nuclear DNA and associated proteins. In this review article, the interaction of neutrophils and sperm cells in t cattle will be described, with a special focus on the formation of neutrophil extracellular traps (NETs).

Varicocele-Mediated Male Infertility: From the Perspective of Testicular Immunity and Inflammation

Background

Varicocele (VC) is present in 35 - 40% of men with infertility. However, current surgical and antioxidant treatments are not completely effective. In addition to oxidative stress, it is likely that other factors such as testicular immune microenvironment disorder contribute to irreversible testicular. Evidence suggests that VC is associated with anti-sperm antibodies (ASAs), spermatogenesis and testosterone secretion abnormalities, and testicular cytokine production. Moreover, inhibition of inflammation can alleviate VC-mediated pathogenesis. The normal function of the testis depends on its immune tolerance mechanism. Testicular immune regulation is complex, and many infectious or non-infectious diseases may damage this precision system.

Results

The testicular immune microenvironment is composed of common immune cells and other cells involved in testicular immunity. The former includes testicular macrophages, T cells, dendritic cells (DCs), and mast cells, whereas the latter include Leydig cells and Sertoli cells (SCs). In animal models and in patients with VC, most studies have revealed an abnormal increase in the levels of ASAs and pro-inflammatory cytokines such as interleukin (IL)-1 and tumor necrosis factor (TNF)-alpha in the seminal plasma, testicular tissue, and even peripheral blood. It is also involved in the activation of potential inflammatory pathways, such as the nucleotide-binding oligomerization domain-like receptor family pyrin domain containing (NLRP)-3 pathway. Finally, the development of VC-mediated infertility (VMI) may be facilitated by abnormal permeability of proteins, such as claudin-11, that constitute the blood-testis barrier (BTB).

Conclusions

The testicular immune response, including the production of ASAs and inflammatory factors, activation of inflammatory pathways, and destruction of the BTB may be involved in the pathogenesis of VMI it is necessary to further explore how patient outcomes can be improved through immunotherapy.

Seminal Plasma Proteomic Biomarkers of Oxidative Stress

The prevalence of idiopathic male infertility is high, up to 75% of patients with abnormal sperm parameters. Hence, the research of its causes is mandatory. Oxidative stress (OS) can be responsible for male infertility in 30–80% of cases. In recent years, seminal plasma (SP) proteomics has developed as a useful tool to provide biomarkers of specific diseases. This systematic review aims to collect the available evidence on the changes of SP proteome in patients exposed to OS to provide possible SP biomarkers of sperm OS. To accomplish this, the following keyterms “seminal fluid proteome”, “seminal plasma proteome”, “oxidative stress”, and “sperm oxidative stress” were used and 137 records were found. Among these, 17 were finally included. Nine proteins involved with OS were found overexpressed in patients with OS. Twenty-three proteins were found differentially expressed in patients with clinical conditions associated with OS, such as varicocele, male accessory gland infection/inflammation, cigarette smoke, and obesity. These proteins do not seem to overlap among the clinical conditions taken into account. We speculate that specific SP proteins may mediate OS in different clinical conditions. Altogether, these results suggest that proteomics could help to better understand some of the molecular mechanisms involved in the pathogenesis of infertility. However, further studies are needed to identify potential biomarkers of male infertility with valuable clinical significance.

"Emerging role of Novel Seminal Plasma Bio-markers in Male Infertility: A Review"

Male infertility has emerged as an important cause of infertility worldwide. There are many factors affecting male fertility and research is going on to know impact of various factors on sperm functions. Semen analysis is gold standard diagnostic test for male infertility, but it is crude method for estimation of male infertility as seminal composition gets affected by environmental factors, infections, other pathologies, hence, results of semen analysis either becomes normal/ambiguous, leading to failure of diagnosis and delayed treatment. Hence, with need of newer, better tests for assessing male factor infertility, seminal plasma is being tested for biomarkers. Seminal plasma is considered gold mine for male fertility as it contains molecules from male reproductive glands which play important role in sperm function. Study of seminal plasma molecules can give an idea about sperm concentration, motility, morphology and cause of infertility and can serve as biomarkers for male infertility. Present review briefs on some of these novel seminal plasma biomarkers which may play significant role in male fertility and can be used in future for better identification, assessment of infertile males.

METHODOLOGY

Literature from 1985 to 2019 was searched from various databases including PUBMED, SCOPUS, Google Scholar on seminal plasma biomarkers using keywords: "seminal plasma protein biomarkers", "novel seminal plasma markers and male infertility", "hormones in seminal plasma and male infertility", "oxidative stress and male infertility", "Reactive Oxygen Species and sperm DNA", "immunoinfertility".

INCLUSION CRITERIA

All full length original or review articles or abstracts on seminal plasma markers and male infertility published in English language in various peer-reviewed journals were considered.

EXCLUSION CRITERIA

Articles published in languages other than English were excluded from the study.

RESULTS

Seminal plasma is a big reservoir of molecules derived from the various male reproductive glands which can be used as potential biomarkers of male fertility.

CONCLUSION

Hence, seminal plasma biomarkers can be used in future for better assessment of male factor infertility, its causes and may play an important role in management of male factor infertility.

Thiol based mechanism internalises interacting partners to outer dense fibers in sperm

The sperm tail outer dense fibres (ODFs) contribute passive structural role in sperm motility. The level of disulphide cross-linking of ODFs and their structural thickness determines flagellar bending curvature and motility. During epididymal maturation, proteins are internalized to modify ODF disulphide cross-linking and enable motility. Sperm thiol status is further altered during capacitation in female tract. This suggests that components in female reproductive tract acting on thiol/disulphides could be capable of modulating the tail stiffness to facilitate modulation of the sperm tail rigidity and waveform en route to fertilization. Understanding the biochemical properties and client proteins of ODFs in reproductive tract fluids will help bridge this gap. Using recombinant ODF2 (aka Testis Specific Antigen of 70 kDa) as bait, we identified client proteins in male and female reproductive fluids. A thiol-based interaction and internalization indicates sperm can harness reproductive tract fluids for proteins that interact with ODFs and likely modulate the tail stiffness en route to fertilization.

Effect of scrotal heating on sperm quality, seminal biochemical substances, and reproductive hormones in human fertile men

At present, male contraceptive methods are only vasectomy and condoms, so it is necessary to research on male contraceptive techniques. The aim of this study is to observe the effects of scrotal heating (SH) on semen parameters, seminal l-carnitine (LC), epidermal growth factor (EGF), macrophage migration inhibitory factor (MIF), reproductive hormones and sperm chromosome numbers of adult healthy men, and to provide the experimental data for male contraception. The scrotums of 30 healthy male volunteers were exposed to the condition of 40 to 43°C SH belt warming 40 minutes each day for successive 2 days per week. The course of SH was continuous for 3 months. Computer-assisted semen analysis and hypo-osmotic swelling test, sperm DNA integrity, l-carnitine, MIF and EGF, and sperm fluorescence in situ hybridization were performed before, during, and after SH. The serum level of follicle stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T) were measured by chemiluminescent immunoassay. The mean parameters of sperm concentration, vitality, and normal morphological sperm were significantly decreased in groups with sperms being collected during 1, 2, and 3 months of SH when compared with those in groups of pre-SH (P < 0.01). Statistically significant differences of sperm DNA fragmentation, normal sperm membrane functionality, levels of LC and MIF in semen, and LH, FSH, and T in serum were observed between the groups of before SH and after SH 3 months and the groups of during SH 1, 2, and 3 months (P < 0.001). The total rate of chromosome number for 13, 18, 21, X, and Y in the 3 months of SH was 13.7-fold greater (13.72%/1.69%) than before SH (P < 0.001). The constant SH can impact the semen quality, sperm DNA integrity, sperm chromosome, LC and MIF, and LH, FSH, and T in serum. Transient SH may be a new method for male contraception.

Semen variables and sperm membrane protein profile of Saanen bucks (Capra hircus) in dry and rainy seasons of the northeastern Brazil (3°S)

The Saanen is a highly productive breed, and for this reason, it has been raised in Brazil, but mostly under climate conditions completely different from where the breed originated. The objective of this study was to investigate variations in semen parameters and sperm membrane proteins from Saanen bucks (n = 7) raised in Northeastern Brazil, during dry season (September, October, and November) and rainy season (March, April, and May). We showed that during the dry season, sperm motility, concentration, and the percentage of normal sperm decreased as compared to the rainy season. Rectal temperatures of bucks had no significant (p > 0.05) variations during the dry and rainy seasons. However, temperatures of left and right skin testis were higher (p < 0.05) during the dry as compared to the rainy season. Expression of three proteins (lysine-specific demethylase 5D, adenosine triphosphate (ATP) synthase subunit d, and radial spoke head protein 9 homolog) in sperm membrane were more intense in rainy season and only one protein (cytosol aminopeptidase) had greater expression in the dry season of the year. Our results show that mechanisms of testicular thermoregulation of Saanen bucks did not prevent a decrease in seminal parameters during the dry season. This deterioration may be related to reduced expression of proteins associated with important functions in sperm membrane.

Peptides in seminal fluid and their role in infertility: a potential role for opiorphin inhibition of neutral endopeptidase activity as a clinically relevant modulator of sperm motility: a review

Infertility is a devastating medical condition that adversely affects emotional health and well-being of couples who desire pregnancy and parenthood. The overall demographic data suggest that the indication for more than one-third of assisted reproductive technology cycles performed in the United States includes male factor infertility. There is increasing recognition of the role that peptides present in seminal plasma have in determining sperm motility. Several recent studies suggest that peptidases, such as neutral endopeptidase (NEP) and aminopeptidase N (APN), impose significant adverse effects on sperm motility. Interestingly, several recent studies demonstrate that there is an endogenous NEP/APN inhibitor peptide called opiorphin in human seminal plasma. Our pilot studies suggest opiorphin promotes sperm motility and may positively influence sperm motility parameters in some cases of males infertility characterized by asthenozoospermia.

Microbiological investigation in male infertility: a practical overview

The roles of inflammation and/or infection of the male accessory sex glands are very important for the potential effects that these conditions may have on male fertility. The clinical andrologist should be aware of the pathophysiological role of the main determinants of sperm damage when these conditions occur, in particular, seminal leukocytes, oxidative stress and cytokines. In addition, it is important to have a good knowledge of the methodologies to be used in clinical practice. This article summarizes the methods used to look for and to identify the micro-organisms responsible for male urogenital tract infections. These include sperm culture, urine culture, urethral swabbing, the Meares–Stamey test and balanopreputial swabbing. Finally, we discuss the role of human papilloma virus infection in male infertility.

Male accessory gland infection and sperm parameters (review)

Male accessory gland infection (MAGI) has been identified among those diagnostic categories which have a negative impact on the reproductive function and fertility in males (Rowe et al., World Health Organization Manual for the Standardised Investigation and Diagnosis of the Infertile Couple, Cambridge University Press, Cambridge, 1993). MAGI is a hypernym which groups the following different clinical categories: prostatitis, prostate-vesiculitis and prostate-vesiculo-epididymitis. Some of the characteristics they share are: common diseases, mainly have a chronic course, rarely cause obstruction of the seminal pathways, can have an unpredictable intracanicular spread to one or more sexual accessory glands of the reproductive tract, as well as to one or both sides. In this review, we show that all components involving the inflammatory response (from the agents which first trigger it to each component of the inflammatory response dynamic) can deteriorate conventional and/or non-conventional sperm parameters arising from one or more of the following mechanisms: altered secretory function of the epididymis, seminal vesicles, and prostate which reduce the antioxidant properties or scavenging role of the seminal plasma; deterioration of spermatogenesis; and (unilateral or bilateral) organic or functional sub-obstruction of the seminal tract.