The Vehicle Determines the Destination: The Significance of Seminal Plasma Factors for Male Fertility

The correlation between human seminal plasma sialoproteins and ejaculate parameters

Sialic acids are negatively charged carbohydrates that are components of saccharide chains covalently linked to macromolecules. Sialylated glycoproteins are important for most biological processes, including reproduction, where they are associated with spermatogenesis, sperm motility, immune responses, and fertilization. Changes in the glycoprotein profile or sialylation in glycoproteins are likely to affect the quality of ejaculate. The aim of this study was to determine differences in the degree of sialylation between normozoospermic ejaculates and ejaculates with a pathological spermiogram using two lectins, Sambucus nigra (SNA) and Maackia amurensis (MAL II/MAA) recognizing α-2,6 or α-2,3 linkage of Sia to galactosyl residues. Our results show a close relationship between seminal plasma (SP) sialoproteins and the presence of anti-sperm antibodies in the ejaculate, apoptotic spermatozoa, and ejaculate quality. Using mass spectrometry, we identified SP sialoproteins such as, semenogelins, glycodelin, prolactin-inducible protein, lactotransferrin, and clusterin that are associated with spermatozoa and contribute to the modulation of the immune response and sperm apoptosis. Our findings suggest a correlation between the degree of SP glycoprotein sialylation and the existence of possible pathological states of spermatozoa and reproductive organs. Glycoproteins sialylation represents a potential parameter reflecting the overall quality of ejaculate and could potentially be utilised in diagnostics.

Human Seminal Extracellular Vesicles Enhance Endometrial Receptivity Through Leukemia Inhibitory Factor

Seminal extracellular vesicles (EVs) contain different subgroups that have diverse effects on sperm function. However, the effect of seminal EVs-especially their subgroups-on endometrial receptivity is largely unknown. Here, we found that seminal EVs could be divided into high-density EVs (EV-H), medium density EVs, and low-density EVs after purification using iodixanol. We demonstrated that EV-H could promote the expression and secretion of leukemia inhibitor factor (LIF) in human endometrial cells. In EV-H-treated endometrial cells, we identified 1274 differentially expressed genes (DEGs). DEGs were enriched in cell adhesion and AKT and STAT3 pathways. Therefore, we illustrated that EV-H enhanced the adhesion of human choriocarcinoma JAr cell spheroids to endometrial cells through the LIF-STAT3 pathway. Collectively, our findings indicated that seminal EV-H could regulate endometrial receptivity through the LIF pathway, which could provide novel insights into male fertility.

Pathophysiology of obesity-related infertility and its prevention and treatment by potential phytotherapeutics

BACKGROUND

Obesity is a complex multifactorial disease in which the accumulation of excess body fat has adverse health effects, as it can increase the risk of several problems, including infertility, in both men and women. Obesity and infertility have risen together in recent years. Against this background, the present review aims to highlight the impact of obesity on infertility and the underlying pathophysiology of obesity-related infertility (ORI) in men and women, and to provide readers with knowledge of current trends in the effective development of phytotherapeutics for its treatment.

METHODS

We thoroughly searched in PubMed, MEDLINE, Scopus, EMBASE, and Google Scholar to find all relevant papers on ORI and the therapeutic effects of phytotherapeutics on ORI in men and women.

RESULTS

The extensive search of the available literature revealed that obesity affects reproductive function through several complex mechanisms such as hyperlipidaemia, hyperinsulinaemia, hyperandrogenism, increased body mass index, disruption of the hormonal milieu, systemic inflammation, oxidative stress, alterations in epigenetics and dysbiosis. On the other hand, several studies reported that phytotherapeutics has a broad therapeutic spectrum of action by improving sex hormone homeostasis, ovarian dysfunction, menstrual cycle and inhibiting ovarian hyperplasia, as well as down-regulating ovarian apoptosis, inflammation and oxidative stress, and controlling metabolic dysfunction in obese women. Male infertility is also addressed by phytotherapeutics by suppressing lipogenesis, increasing testosterone, 3β-HSD and 17β-HSD levels, improving sperm parameters and attenuating testicular dyslipidaemia, oxidative stress, inflammation and germ cell apoptosis.

CONCLUSIONS

In the present review, we discussed the effects of obesity on reproductive dysfunction in men and women and the underlying pathophysiology of ORI. In addition, the therapeutic effect of phytotherapeutics against ORI was highlighted.

Critical Factors in Sample Collection and Preparation for Clinical Metabolomics of Underexplored Biological Specimens

This review article compiles critical pre-analytical factors for sample collection and extraction of eight uncommon or underexplored biological specimens (human breast milk, ocular fluids, sebum, seminal plasma, sweat, hair, saliva, and cerebrospinal fluid) under the perspective of clinical metabolomics. These samples are interesting for metabolomics studies as they reflect the status of living organisms and can be applied for diagnostic purposes and biomarker discovery. Pre-collection and collection procedures are critical, requiring protocols to be standardized to avoid contamination and bias. Such procedures must consider cleaning the collection area, sample stimulation, diet, and food and drug intake, among other factors that impact the lack of homogeneity of the sample group. Precipitation of proteins and removal of salts and cell debris are the most used sample preparation procedures. This review intends to provide a global view of the practical aspects that most impact results, serving as a starting point for the designing of metabolomic experiments.

Relevance of PUFA-derived metabolites in seminal plasma to male infertility

Aim

This study aims to investigate the biological effects of polyunsaturated fatty acid (PUFA)-derived metabolites in seminal plasma on male fertility and to evaluate the potential of PUFA as a biomarker for normozoospermic male infertility.

Methods

From September 2011 to April 2012, We collected semen samples from 564 men aged 18 to 50 years old (mean=32.28 years old)ch., residing in the Sandu County, Guizhou Province, China. The donors included 376 men with normozoospermia (fertile: n=267; infertile: n=109) and 188 men with oligoasthenozoospermia (fertile: n=121; infertile: n=67). The samples thus obtained were then analyzed by liquid chromatography-mass spectrometry (LC-MS) to detect the levels of PUFA-derived metabolites in April 2013. Data were analyzed from December 1, 2020, to May 15, 2022.

Results

Our analysis of propensity score-matched cohorts revealed that the concentrations of 9/26 and 7/26 metabolites differed significantly between fertile and infertile men with normozoospermia and oligoasthenozoospermia, respectively (FDR < 0.05). In men with normozoospermia, higher levels of 7(R)-MaR1 (HR: 0.4 (95% CI [0.24, 0.64]) and 11,12-DHET (0.36 (95% CI [0.21, 0.58]) were significantly associated with a decreased risk of infertility, while higher levels of 17(S)-HDHA (HR: 2.32 (95% CI [1.44, 3.79]), LXA5 (HR: 8.38 (95% CI [4.81, 15.24]), 15d-PGJ2 (HR: 1.71 (95% CI [1.06, 2.76]), and PGJ2 (HR: 2.28 (95% CI [1.42, 3.7]) correlated with an increased risk of infertility. Our ROC model using the differentially expressed metabolites showed the value of the area under the curve to be 0.744.

Conclusion

The PUFA-derived metabolites 7(R)-MaR1, 11,12-DHET, 17(S)-HDHA, LXA5, and PGJ2 might be considered as potential diagnostic biomarkers of infertility in normozoospermic men.

Mass Spectrometry-Based Untargeted Approaches to Reveal Diagnostic Signatures of Male Infertility in Seminal Plasma: A New Laboratory Perspective for the Clinical Management of Infertility?

Male infertility has been recognized as a global health problem. Semen analysis, although considered the golden standard, may not provide a confident male infertility diagnosis alone. Hence, there is the urgent request for an innovative and reliable platform to detect biomarkers of infertility. The rapid expansion of mass spectrometry (MS) technology in the field of the 'omics' disciplines, has incredibly proved the great potential of MS-based diagnostic tests to revolutionize the future of pathology, microbiology and laboratory medicine. Despite the increasing success in the microbiology area, MS-biomarkers of male infertility currently remain a proteomic challenge. In order to address this issue, this review encompasses proteomics investigations by untargeted approaches with a special focus on experimental designs and strategies (bottom-up and top-down) for seminal fluid proteome profiling. The studies reported here witness the efforts of the scientific community to address these investigations aimed at the discovery of MS-biomarkers of male infertility. Proteomics untargeted approaches, depending on the study design, might provide a great plethora of biomarkers not only for a male infertility diagnosis, but also to address a new MS-biomarkers classification of infertility subtypes. From the early detection to the evaluation of infertility grade, new MS-derived biomarkers might also predict long-term outcomes and clinical management of infertility.

New horizons in human sperm selection for assisted reproduction

Male infertility is a commonly encountered pathology that is estimated to be a contributory factor in approximately 50% of couples seeking recourse to assisted reproductive technologies. Upon clinical presentation, such males are commonly subjected to conventional diagnostic andrological practices that rely on descriptive criteria to define their fertility based on the number of morphologically normal, motile spermatozoa encountered within their ejaculate. Despite the virtual ubiquitous adoption of such diagnostic practices, they are not without their limitations and accordingly, there is now increasing awareness of the importance of assessing sperm quality in order to more accurately predict a male's fertility status. This realization raises the important question of which characteristics signify a high-quality, fertilization competent sperm cell. In this review, we reflect on recent advances in our mechanistic understanding of sperm biology and function, which are contributing to a growing armory of innovative approaches to diagnose and treat male infertility. In particular we review progress toward the implementation of precision medicine; the robust clinical adoption of which in the setting of fertility, currently lags well behind that of other fields of medicine. Despite this, research shows that the application of advanced technology platforms such as whole exome sequencing and proteomic analyses hold considerable promise in optimizing outcomes for the management of male infertility by uncovering and expanding our inventory of candidate infertility biomarkers, as well as those associated with recurrent pregnancy loss. Similarly, the development of advanced imaging technologies in tandem with machine learning artificial intelligence are poised to disrupt the fertility care paradigm by advancing our understanding of the molecular and biological causes of infertility to provide novel avenues for future diagnostics and treatments.

Dolichandrone serrulata flower improves seminal biochemical parameters and proteins in T2DM rats induced by a high-fat diet and streptozotocin

CONTEXT

Although Dolichandrone serrulata (Wall. ex DC.) Seem (Bignoniaceae) flower (DSF) improves hyperglycaemia, testicular damage and sperm quality in type 2 diabetes mellitus (T2DM) animals, its effects on the seminal vesicles, secreting seminal plasma, are unknown.

OBJECTIVE

This study reports the protective effects of DSF on seminal dysfunction in T2DM rats.

MATERIALS AND METHODS

Male Sprague-Dawley rats were divided into four groups (control, T2DM, T2DM + DSF200 and T2DM + DSF600; 10 animals/group). The control group was fed a low-fat diet for 14 days prior to single saline injection, whereas T2DM group was given a high-fat diet and injected with streptozocin (50 mg/kg body weight). The T2DM-induced rats were fed DSF orogastrically (200 and 600 mg/kg body weight) for 28 consecutive days. At the end of the experiment, biochemical components, malondialdehyde (MDA), histology and protein expression in seminal lysate were evaluated.

RESULTS

DSF increased the levels of serum phosphorus (13.66 ± 0.59 mg/dL), ALP (11.85 ± 0.99 U/L), GOT (3938.23 ± 251.41 U/L) and GPT (34.16 ± 4.93), decreased MDA levels in seminal tissue, and elevated the serum testosterone in the T2DM rats. Treatment with DSF ameliorated histological damage, significantly increased seminal 44 and 31 kDa TyrPho protein expression, and decreased that of caspase 3 and 9.

CONCLUSIONS

DSF extract was able to mitigate seminal dysfunction in T2DM rats via improvements of tyrosine phosphorylation, testosterone level and biochemical substances, as well as reductions of caspase proteins. DSF may be developed as an alternative medicine in treating of T2DM male subfertility and progressive complications.

Diagnosis of bacteriospermia and its impact on spermogram parameters in adolescents with varicocele

Infectious etiology is the cause of about 15% of cases of male infertility. And if sexually transmitted infections are easily diagnosed, the role of asymptomatic bacteriospermia in the formation of infertility in men, and especially in adolescents against the background of the existing pathology of the reproductive sphere (varicocele), remains insufficiently studied. A microbiological study in the ejaculate of adolescents revealed the following types of bacteria: Escherichia coli, Enterococcus faecalis, Corynebacterium glucuronolyticum, Corynebacterium minitissimum, Streptococcus anginosus, Staphylococcus epidermidis, Staphylococcus haemolyticus. Bacteria in the ejaculate were also detected during semen analysis and electron microscopic examination of spermatozoa. With abundant growth of microorganisms in a monoculture or an association of two microorganisms present in a moderate amount, in all cases, violations of sperm motility, an increase in the viscosity of the ejaculate, the presence of leukocytes in the seminal fluid were detected, and damage to the chromatin, acrosome and mitochondria was recorded at the ultrastructural level, which may indicate active infection. When bacterial flora was detected in a small and moderate amount (<10 CFU/ml), no pathological changes in the ejaculate were observed. The microflora of the ejaculate of the examined adolescents is represented by gram-positive microflora. Simultaneous study of the ejaculate sample by bacteriological seeding, the performance of spermogram and EMIS allowed to increase the detection of bacteriospermia. Opportunistic pathogens with abundant growth or their various combinations can serve as a factor in the development of pathospermia. It is possible to distinguish an active infection from commensal microflora or sample contamination not only by the presence of bacteria in the ejaculate and their quantitative accounting, but also by the degree of damage to the function of spermatozoa and pathological changes in the parameters of the ejaculate, by combining diagnostic methods. Most often, in the presence of bacteria in the ejaculate, asthenozoospermia is diagnosed.

The Activated AMPK/mTORC2 Signaling Pathway Associated with Oxidative Stress in Seminal Plasma Contributes to Idiopathic Asthenozoospermia

Asthenozoospermia is a common form of abnormal sperm quality in idiopathic male infertility. While most sperm-mediated causes have been investigated in detail, the significance of seminal plasma has been neglected. Herein, we aimed to investigate the possible pathogenic factors leading to decreased sperm motility based on seminal plasma. Semen was collected from normo- (NOR, n = 70), idiopathic oligo- (OLI, n = 57), and idiopathic asthenozoospermic (AST, n = 53) patients. Using attenuated total reflection-Fourier transform infrared coupled with chemometrics, distinct differences in the biochemical compositions of nucleic acids, protein structure (amides I, II, and III), lipids, and carbohydrates in seminal plasma of AST were observed when compared to NOR and OLI. Compared with NOR and OLI, the levels of peptide aggregation, protein phosphorylation, unsaturated fatty acid, and lipid to protein ratio were significantly increased in AST; however, the level of lipid saturation was significantly decreased in seminal plasma of AST. Compared with NOR, the levels of ROS, MDA, 8-iso-prostaglandin F2α (8-isoPGF2α), and the ratio of phospho-AMPKα/AMPKα1 were significantly increased in AST; however, the levels of SOD, glutathione S-transferase (GSTs), protein carbonyl derivative (PC), and the ratio of phospho-Rictor/Rictor were significantly decreased in seminal plasma of AST. Changes of the AMPK/mTORC2 signaling in the seminal microenvironment possibly induce abnormal glucose and lipid metabolism, which impairs energy production. Oxidative stress potentially damages seminal plasma lipids and proteins, which in turn leads to impaired sperm structure and function. These findings provide evidence that the changes in seminal plasma compositions, oxidative stress, and activation of the AMPK/mTORC2 signaling contribute to the development of asthenozoospermia.

Semenogelin, a coagulum macromolecule monitoring factor involved in the first step of fertilization: A prospective review

Human male infertility affects approximately 1/10 couples worldwide, and its prevalence is found more in developed countries. Along with sperm cells, the secretions of the prostate, seminal vesicle and epididymis plays a major role in proper fertilization. Many studies have proven the functions of seminal vesicle secretions, especially semenogelin protein, as an optimiser for fertilization. Semenogelin provides the structural components for coagulum formation after ejaculation. It binds with eppin and is found to have major functions like motility of sperm, transporting the sperm safely in the immune rich female reproductive tract until the sperm cells reach the egg intact. The capacitation process is essential for proper fertilization and semenogelin involved in mediating capacitation in time. Also, it has control of events towards the first step in the fertilization process. It is a Zn ions binding protein, and Zn ions act as a cofactor that helps in the proper motility of sperm cells. Therefore, any imbalance in protein that automatically affect sperm physiology and fertility status. This review sheds a comprehensive and critical view on the significant functions of semenogelin in fertilization. This review can open up advanced proteomics research on semenogelin towards unravelling molecular mechanisms in fertilization.

Seminal Plasma: Relevant for Fertility?

Seminal plasma (SP), the non-cellular component of semen, is a heterogeneous composite fluid built by secretions of the testis, the epididymis and the accessory sexual glands. Its composition, despite species-specific anatomical peculiarities, consistently contains inorganic ions, specific hormones, proteins and peptides, including cytokines and enzymes, cholesterol, DNA and RNA-the latter often protected within epididymis- or prostate-derived extracellular vesicles. It is beyond question that the SP participates in diverse aspects of sperm function pre-fertilization events. The SP also interacts with the various compartments of the tubular genital tract, triggering changes in gene function that prepares for an eventual successful pregnancy; thus, it ultimately modulates fertility. Despite these concepts, it is imperative to remember that SP-free spermatozoa (epididymal or washed ejaculated) are still fertile, so this review shall focus on the differences between the in vivo roles of the SP following semen deposition in the female and those regarding additions of SP on spermatozoa handled for artificial reproduction, including cryopreservation, from artificial insemination to in vitro fertilization. This review attempts, including our own results on model animal species, to critically summarize the current knowledge of the reproductive roles played by SP components, particularly in our own species, which is increasingly affected by infertility. The ultimate goal is to reconcile the delicate balance between the SP molecular concentration and their concerted effects after temporal exposure in vivo. We aim to appraise the functions of the SP components, their relevance as diagnostic biomarkers and their value as eventual additives to refine reproductive strategies, including biotechnologies, in livestock models and humans.