Lipid concentrations and semen quality: the LIFE study

Lipidomic and transcriptomic characteristics of boar seminal plasma extracellular vesicles associated with sperm motility

Seminal plasma extracellular vesicles (SPEVs) play an important role in regulating sperm motility by delivering various cargoes, such as miRNAs, mRNAs, proteins and metabolites. However, information on the lipid compositions of SPEVs and their roles in semen quality is limited. Here, we performed high-throughput transcriptomic and lipidomic analysis on SPEVs isolated from 20 boars with high or low sperm motility. Then, we evaluated the lipid composition and gene expression characteristics of SPEVs and identified the specific lipids and genes related to sperm motility. As a result, a total of 26 lipid classes were identified in SPEVs, and five subclasses, CerG2, CerG3, LPE, LPS and TG, were significantly different in boars with high and low sperm motility. In addition, 195 important lipids and 334 important genes were identified by weighted gene coexpression analysis (WGCNA) and differential expression analysis. We observed that several important genes and lipids in SPEVs potentially influence sperm motility via glycerophospholipid metabolism, glycerolipid metabolism, the sphingolipid signaling pathway and the ferroptosis pathway. Furthermore, we found a significant correlation between the content of 22 lipids and the expression levels of 67 genes (|cor| > 0.8, P < 0.05). Moreover, we observed that three important gene-lipid linkages (CerG1 (d22:0/24:0) - RCAN3, Cer (d18:1/24:0) - SCFD2 and CerG1 (d18:0/24:1) - SCFD2) were strongly correlated with sperm motility. Based on the results, some genes and lipids in SPEVs may play important roles in sperm motility by interacting with sperm through important pathways.

Male infertility risk and plasma lipidome: a Mendelian randomization study

Background

In recent years, the decline in sperm quality in men has become a global trend. There is a close relationship between sperm quality and pregnancy outcome. There is a large body of literature supporting the role of plasma lipidome in male infertility, while the complex mechanisms between them and male infertility are still less clear. Systematic study of the causal relationship between plasma lipidome and MI can help to provide new therapeutic ideas and targets for male infertility.

Methods

In this study, we used a two-sample Mendelian randomization analysis based on Genome-wide association studies pooled data of 179 causal relationships between plasma lipidome and male infertility. We used employed the inverse variance weighted method as the main analysis to assess causality between exposure and outcome, in addition to MR-Egger, Weighted median as complementary methods, and tests for multiplicity and heterogeneity.

Results

We identified 13 plasma lipidome comprising 4 types of plasma lipidome that were associated with male infertility. Among these, 9 plasma lipidome were found to be protective factors, while 4 were risk factors. Notably, the largest proportion of these plasma lipidome were triglyceride types, with Sphingomyelin (d40:1) exhibiting the strongest association with male infertility.

Conclusion

These findings contribute to the current better understanding of male infertility and provide new perspectives on the underlying etiology of male infertility as well as prevention and treatment strategies. In addition, clinical trial validation is needed to assess the potential of these plasma lipidome as biomarkers.

The Association of Sperm DNA Fragmentation With Serum Lipid Profile Among Males With Abnormal Semen Parameters: An Analytical Cross-Sectional Study

BACKGROUND

Through the ages, infertility, affecting 8% to 12% of couples worldwide, has been a perturbing clinical problem. Approximately 40% to 50% of all infertility cases are due to 'male factor' infertility. Semen analysis is crucial in routinely evaluating idiopathic male infertility. Studies support the idea that semen parameters are associated with serum lipids and sperm DNA fragmentation (SDF). Therefore, it is possible to evaluate male infertility by serum lipid levels, especially before assisted reproduction technology, and modify it by bringing about lifestyle modifications. This study aimed to measure the correlation of SDF with levels of total cholesterol (TC), triglycerides (TG), very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) among males with abnormal semen parameters.

METHODS

A cross-sectional analytical study was conducted in the infertility clinic of a tertiary care hospital. A total of 106 infertile males with abnormal semen analysis as per the WHO criteria (2010) were enrolled in the study. After routine semen analysis, SDF was studied using the comet assay. The serum fasting lipid profile was analyzed using the spectrophotometric kit in the autoanalyzer. The relationship of SDF with serum lipid profile parameters was analyzed.

RESULTS

Out of 106 infertile men, 52% (n = 55) had severe SDF. A modest positive correlation was observed between SDF (percentage of DNA in comet tail) and serum lipid values (serum TG, serum LDL, and serum VLDL).

CONCLUSIONS

Our study is novel in its research on the correlation between SDF and serum lipid values. Based on the findings of our study, it can be concluded that a significant level of SDF was observed in men with high levels of serum TG, LDL, and VLDL. This provokes a potential relationship between sperm DNA integrity and serum lipid profile, which warrants further research.

Decreased Ubiquitination and Acetylation of Histones 3 and 4 Are Associated with Obesity-Induced Disorders of Spermatogenesis in Mice

BACKGROUND

Obesity, a chronic metabolic disorder, is related to cardiovascular diseases, diabetes, cancer, and reproductive disorders. The relationship between obesity and male infertility is now well recognized, but the mechanisms involved are unclear. We aimed to observe the effect of obesity on spermatogenesis and to investigate the role of histone ubiquitination and acetylation modifications in obesity-induced spermatogenesis disorders.

METHODS

Thirty male C57BL/6J mice were randomly divided into two groups. The control group was fed with a general maintenance diet (12% fat), while a high-fat diet (HFD) group was fed with 40% fat for 10 weeks; then, they were mated with normal females. The fertility of male mice was calculated, testicular and sperm morphology were observed, and the expression levels of key genes and the levels of histone acetylation and ubiquitination modification during spermatogenesis were detected.

RESULTS

The number of sperm was decreased, as well as the sperm motility, while the number of sperm with malformations was increased. In the testes, the mRNA and protein expression levels of gonadotropin-regulated testicular RNA helicase (GRTH/DDX25), chromosome region maintenance-1 protein (CRM1), high-mobility group B2 (HMGB2), phosphoglycerate kinase 2 (PGK2), and testicular angiotensin-converting enzyme (tACE) were decreased. Furthermore, obesity led to a decrease in ubiquitinated H2A (ubH2A) and reduced levels of histone H3 acetylation K18 (H3AcK18) and histone H4 acetylation K5, K8, K12, and K16 (H4tetraAck), which disrupted protamine 1 (Prm1) deposition in testis tissue.

CONCLUSION

These results suggest that low levels of histone ubiquitination and acetylation are linked with obesity-induced disorders during spermatogenesis, contributing to a better understanding of obesity-induced damage to male reproduction.

A ripple effect? The impact of obesity on sperm quality and function

Infertility affects approximately 15% of couples trying to conceive. Male-related causes account for roughly 50% of cases, with obesity emerging as a possible significant factor. Obesity, defined as a body mass index of 30.0 or higher, has become a widespread epidemic associated with numerous health issues, including a decrease of fertility. This review discusses the relationship between obesity and male infertility, particularly focusing on sperm quality and function. An overview of the literature suggests that obesity may influence the male reproductive system via disruptions in hormonal profiles, oxidative stress, and inflammation, leading to changes in sperm parameters. Several studies have discussed if obesity causes a decrease in sperm concentration, motility, and normal morphology, so far without a consensus being reached. However, available evidence suggests an impairment of sperm function in obese men, due to an increase in DNA damage and oxidative stress, impaired mitochondrial function and acrosome reaction in response to progesterone. Finally, the relationship between obesity and assisted reproductive technologies outcomes remains debatable, with conflicting evidence regarding the influence on fertilisation, pregnancy, and live birth rates. Therefore, the actual impact of obesity on human spermatozoa still needs to be clarified, due to the multiple factors potentially in play.

Glucose transporters (GLUTs): Underreported yet crucial molecules in unraveling testicular toxicity

Glucose transporters (GLUTs) are crucial in maintaining glucose homeostasis and supporting energy production in various tissues, including the testes. This review article delves into the distribution and function of GLUTs in distinct testicular cell types, namely Leydig cells, Sertoli cells, germ cells, and spermatozoa, shedding light on their significance in the context of male reproductive health-an issue of mounting global concern. Furthermore, this article examines the implications of GLUT dysregulation in testicular dysfunction. Altered GLUT expression has been associated with impaired steroidogenesis, spermatogenesis, sperm count, and motility in various animal models. Lastly, the article underscores the potential therapeutic implications of targeting GLUTs concerning testicular toxicity. Insights gleaned from studies in diabetes and cancer suggest that modulating GLUT expression and translocation could present novel strategies for mitigating testicular dysfunction and safeguarding male fertility. In summary, the intricate interplay between GLUTs, glucose metabolism, and testicular health underscores the significance of sustaining testicular glucose homeostasis for male reproductive health. Manipulating GLUTs presents an innovative avenue to address testicular dysfunction, potentially revolutionizing therapeutic strategies to restore male fertility and overall reproductive well-being. Future research in this field holds great promise for advancing male fertility treatments and reproductive health interventions.

Lipidomic Profile of Human Sperm Membrane Identifies a Clustering of Lipids Associated with Semen Quality and Function

Reduced sperm motility and/or count are among the major causes of reduced fertility in men, and sperm membranes play an important role in the spermatogenesis and fertilization processes. However, the impact of sperm lipid composition on male fertility remains under-investigated. The aim of the present study was to perform a lipidomic analysis of human sperm membranes: we performed an untargeted analysis of membrane lipid composition in fertile (N = 33) and infertile subjects (N = 29). In parallel, we evaluated their serum lipid levels. Twenty-one lipids were identified by their mass/charge ratio and post-source decay spectra. Sulfogalactosylglycerolipid (SGG, seminolipid) was the most abundant lipid component in the membranes. In addition, we observed a significant proportion of PUFAs. Important differences have emerged between the fertile and infertile groups, leading to the identification of a lipid cluster that was associated with semen parameters. Among these, cholesterol sulfate, SGG, and PUFAs represented the most important predictors of semen quality. No association was found between the serum and sperm lipids. Dietary PUFAs and SGG have acknowledged antioxidant functions and could, therefore, represent sensitive markers of sperm quality and testicular function. Altogether, these results underline the important role of sperm membrane lipids, which act independently of serum lipids levels and may rather represent an independent marker of reproductive function.

Analyzing the impact and mechanism of bisphenol A on testicular lipid metabolism in Gobiocypris rarus through integrated lipidomics and transcriptomics

Bisphenol A (BPA) is one of the most common environmental endocrine chemicals, known for its estrogenic effects that can interfere with male spermatogenesis. Lipids play crucial roles in sperm production, capacitation, and motility as important components of the sperm plasma membrane. However, limited research has explored whether BPA affects lipid metabolism in the testes of male fish and subsequently impacts spermatogenesis. In this study, we employed Gobiocypris rarus rare minnow as a research model and exposed them to environmentally relevant concentrations of BPA (15 μg/L) for 5 weeks. We assessed sperm morphology and function and analyzed changes in testicular lipid composition and transcriptomics. The results demonstrated a significant increase in the sperm head membrane damage rate, along with reduced sperm motility and fertilization ability due to BPA exposure. Lipidomics analysis revealed that BPA increased the content of 11 lipids while decreasing the content of 6 lipids in the testes, particularly within glycerophospholipids, glycerolipids, and sphingolipid subclasses. Transcriptomics results indicated significant up-regulation in pathways such as cholesterol metabolism, peroxisome proliferator-activated receptor signaling, and fat digestion and absorption, with significant alterations in key genes related to lipid metabolism, including apolipoprotein A-I, apolipoprotein C-I, and translocator protein. These findings suggest that BPA exposure can induce testicular lipid metabolism disruption in rare minnows, potentially resulting in abnormalities in rare minnow spermatogenesis.

Serum lipid profile levels and semen quality: new insights and clinical perspectives for male infertility and men's health

PURPOSE

Several clinical scenarios regulate the final ejaculated semen, which is pivotal to reproductive success. Sperm motility and plasma membrane fusogenic activity primarily rely on the peculiar sperm lipid composition, influenced by the patient's metabolism, genetics, nutritional, environmental status, and concomitant clinical entities such as varicocele. This study aimed to determine the relationship between serum lipid profile and testicular function (semen quality and testosterone levels).

METHODS

This retrospective study uses medical charts of 278 infertile men who attended andrological care between 2000 and 2019. Seminal analysis data, lipid profile, and total serum testosterone were collected. A multiple linear regression analysis was performed to evaluate the influence of the lipid parameters on the seminal variables. Statistical analyses were carried out with p ≤ 0.05 considered statistically significant.

RESULTS

Seminal creatine kinase activity (p = 0.024) is negatively related to HDL (p = 0.032) and triglycerides (p = 0.037), while total testosterone (p < 0.0001) and seminal volume (p = 0.046) appeared both to be negatively related to triglycerides (p = 0.030 and p = 0.033, respectively).

CONCLUSION

Medical advice commonly advocated to prevent endothelial dysfunction and cardiovascular disease and improve HDL-cholesterol and triglyceride levels in dyslipidemic patients should also be given to infertile men. Physicians should give patients a thorough assessment, including the blood lipid profile, hormonal status, and routine seminal examinations. We propose a more comprehensive men´s health check-up for the infertile male population, not limited to a simple evaluation of basic sperm parameters.

Effects of Dietary Cholesterol Regulation on Spermatogenesis of Gobiocypris rarus Rare Minnow

Cholesterol is an important component of cell membranes, and also a precursor for the synthesis of sex hormones, playing an important role in reproduction. However, few studies have focused on cholesterol and reproductive health. To investigate the toxic effects of different cholesterol levels on the spermatogenesis of rare minnows, we regulate the cholesterol content in fish by feeding them a high-cholesterol diet and cholesterol inhibitor pravastatin, and cholesterol levels, sex hormone (T and 11KT) levels, testis histology, sperm morphology and function, and the expression of genes related to sex hormone synthesis were investigated. The research findings indicate that increasing cholesterol levels significantly increases the liver weight and hepatic-somatic index, as well as the total cholesterol and free cholesterol levels in the testis, liver, and plasma of rare minnow, while inhibiting cholesterol has the opposite effect (p < 0.05). However, both increasing and decreasing cholesterol levels can suppress rare minnow testicular development, as evidenced by a decrease in testis weight, lowered gonadosomatic index, suppressed sex hormone levels, and reduced mature sperm count. Further exploration revealed that the expression of sex hormone synthesis-related genes, including star, cyp19a1a, and hsd11b2, was significantly affected (p < 0.05), which may be an important reason for the decrease in sex hormone synthesis and consequent inhibition of testicular development. At the same time, the fertilization ability of mature sperm in both treatment groups significantly decreased. Scanning electron microscopy and fluorescence polarization tests showed that reducing cholesterol levels significantly increased the rate of sperm head cell membrane damage, while both increasing and decreasing cholesterol levels led to a reduction in sperm cell membrane fluidity, which may be the main reason for the decrease in sperm fertilization ability. This study demonstrates that both increasing and decreasing the levels of cholesterol are detrimental to the fish spermatogenesis, providing fundamental information for the study of fish reproduction and also a reference for the causes of male reproductive dysfunction.

The Association Between Lipid Serum and Semen Parameters: a Systematic Review

Increased lipid levels sometimes not only affect sexual function but also are considered to harm semen quality. It is often a suspicion that elevated lipids are a factor in infertility. We conduct a systematic review. Articles that met the criteria were identified according to The Preferred Reporting Items for Systematic Review and Meta-analysis of recommendations in the PubMed, ProQuest, EBSCO, Web of Science Wiley Online, Springer Link, Scopus, and Science Direct databases with no time restriction for publication. Seven studies are eligible for qualitative analysis from nine studies that have the potential to be assessed. These studies measure the correlation of serum lipids (VLDL, HDL, LDL, triglycerides, total cholesterol, free cholesterol, phospholipids, free fatty acids) with semen parameters (concentration, motility, morphology, DNA fragmentation index). Although not all studies consistently report that lipids impact semen quality, this review suspects that lipids have a significant impact on sperm quality. This study implies that it is necessary to maintain lipid levels to maintain sperm quality and quality of life. However, further investigation with an observational cohort study design needs to be carried out to assess the effect of lipids on semen quality more precisely for the promotion of reproductive health care.

Semen rheology and its relation to male infertility

Infertility affects 15% of couples of reproductive age worldwide. In spite of many advances in understanding and treating male infertility, there is still a number of issues that need further investigation and translation to the clinic. Here, we review the current knowledge and practice concerning semen rheology and its relation with pathological states affecting male infertility. Although it is well recognized that altered rheological properties of semen can impair normal sperm movement in the female reproductive tract, routine semen analysis is mostly focused on number, motility and morphology of spermatozoa, and includes only an approximate, operator-dependent measure of semen viscosity. The latter is based on the possible formation of a liquid thread from a pipette where a semen sample has been aspirated, a method that is sensitive not only to viscosity but also to elongational properties and surface tension of semen. The formation of a liquid thread is usually associated with a gel-like consistency of the sample and changes in spermatozoa motility in such a complex medium are still to be fully elucidated. The aim of this review is to point out that a more quantitative and reliable characterization of semen rheology is in order to improve the current methods of semen analysis and to develop additional tools for the diagnosis and treatment of male infertility.

Relative Abundance of Lipid Metabolites in Spermatozoa across Three Compartments

Male fertility, as manifest by the quantity and progressive motility of spermatozoa, is negatively impacted by obesity, dyslipidaemia and metabolic disease. However, the relative distribution of lipids in spermatozoa and the two compartments which supply lipids for spermatogenesis (seminal fluid and blood serum) has not been studied. We hypothesised that altered availability of lipids in blood serum and seminal fluid may affect the lipid composition and progressive motility of sperm. 60 men of age 35 years (median (range 20-45) and BMI 30.4 kg/m² (24-36.5) under preliminary investigation for subfertility were recruited at an NHS clinic. Men provided samples of serum and semen, subject to strict acceptance criteria, for analysis of spermatozoa count and motility. Blood serum (n = 60), spermatozoa (n = 26) and seminal fluid (n = 60) were frozen for batch lipidomics analysis. Spermatozoa and seminal fluid had comparable lipid composition but showed marked differences with the serum lipidome. Spermatozoa demonstrated high abundance of ceramides, very-long-chain fatty acids (C20-22), and certain phospholipids (sphingomyelins, plasmalogens, phosphatidylethanolamines) with low abundance of phosphatidylcholines, cholesterol and triglycerides. Men with spermatozoa of low progressive motility had evidence of fewer concentration gradients for many lipid species between blood serum and spermatozoa compartments. Spermatozoa are abundant in multiple lipid species which are likely to contribute to key cellular functions. Lipid metabolism shows reduced regulation between compartments in men with spermatozoa with reduced progressive motility.

Lipid Signaling During Gamete Maturation

Cell lipids are differentially distributed in distinct organelles and within the leaflets of the bilayer. They can further form laterally defined sub-domains within membranes with important signaling functions. This molecular and spatial complexity offers optimal platforms for signaling with the associated challenge of dissecting these pathways especially that lipid metabolism tends to be highly interconnected. Lipid signaling has historically been implicated in gamete function, however the detailed signaling pathways involved remain obscure. In this review we focus on oocyte and sperm maturation in an effort to consolidate current knowledge of the role of lipid signaling and set the stage for future directions.

Dietary quercetin and vitamin E supplementation modulates the reproductive performance and antioxidant capacity of aged male breeder chickens

Aged male chickens experience rapid declines in spermatogenesis, antioxidant capacity, immunity, and hormone synthesis. Vitamin E plays a significant role in reproduction, nervous system function, and disease resistance in animals. Quercetin also exerts many biological effects, such as antioxidant ability, immunostimulation, and protection of spermatozoal plasma membranes. This study evaluated the effects of combining dietary quercetin (Q) and vitamin E (VE) on sperm quality, antioxidant capacity, immunity, and expression of genes related to spermatogenesis, immunity, apoptosis, and inflammation in aged male chickens. A total of 120 Tianfu breeder male chickens (65 wk old) were randomly allotted to 4 treatments with 3 replicates (10 birds each). The birds were fed diets containing Q (0.4g/kg), VE (0.2g/kg), Q+VE (0.4g/kg + 0.2g/kg), and a basal diet for 11 wk. At the end of the experimental period, blood, semen, liver, testes, and spleen samples were collected from 2 birds per replicate. Serum hormones, antioxidant parameters, cytokines, and immunoglobulins were evaluated; and the mRNA expression of genes related to spermatogenesis, apoptosis, and inflammation are determined in the testes and liver tissues.

The results showed that the combination quercetin and vitamin E significantly promoted the sperm count and motility, as well as elevated the levels of testosterone, follicle-stimulating hormone, and luteinizing hormone, antioxidant enzymes (Superoxide dismutase, Glutathione, and Total antioxidant capacity), and serum immunoglobulins (IgA and IgM) in the aged male chickens; also Q+VE showed protective effects on the liver against injury. In addition, Q+VE significantly increased the expression of genes related to spermatogenesis (AR, pgk2, Cyclin A1, and Cyclin A2), immunity (IFN-γ and IL-2), and anti-inflammatory cytokines (IL-10) (P < 0.05), whereas the expression of proinflammatory cytokines (IL-1β and IL-6) was decreased (P < 0.05). Taken together, these data indicate that the combination of quercetin and vitamin E improved reproductive characteristics such as spermatogenesis, sperm quality, and hormone regulation, as well as promoted antioxidant defense, hepatoprotective capacity, and immune response in aged male chickens without any detrimental effects.

Bisphenol A regulates apolipoprotein A1 expression through estrogen receptors and DNA methlylation and leads to cholesterol disorder in rare minnow testis

Bisphenol A (BPA) is a well-known plasticizer that widely distributed in the aquatic environment. BPA has many adverse effects on reproduction. However, few studies have investigated the mechanism of BPA affecting reproduction from the perspective of lipid metabolism. Apolipoprotein A1 (ApoA1) is the major component of high-density lipoprotein (HDL), and plays critical roles in reverse cholesterol transport (RCT). In this study, in order to investigate the effect and molecular mechanism of BPA on testicular ApoA1 and the role of ApoA1 in BPA induced abnormal spermatogenesis, adult male rare minnow Gobiocypris rarus were exposed to 15 μg/L of BPA for 1, 3 and 5 weeks. Results showed that BPA could significantly affect testicular ApoA1 mRNA and protein levels, testicular cholesterol levels, plasmatic sex hormone levels and the integrity of sperm head membrane. The main mechanism of BPA regulating ApoA1 expression is to alter Esr recruitment and CpG sites DNA methylation in ApoA1 promoter. The induced ApoA1 up-regulated high density lipoprotein cholesterol levels and enhanced RCT, and finally decreased the testicular free cholesterol levels. This is likely a key mechanism by which BPA induces sex hormone disorder and sperm head membrane damage. The present study reveals the mechanism by which BPA interferes with spermatogenesis from the perspective of cholesterol transport.

Evaluation of the role of Chlamydia trachomatis in primary male infertility

AIMS

This study aimed to find out the potential role of Chlamydia trachomatis (C. trachomatis) in male primary infertility and to recommend an easy, rapid, and sensitive diagnostic tool for its detection.

METHODS

Semen samples were collected from male patients who presented with primary infertility and from age-matched healthy controls. These samples were analysed according to the World Health Organization guidelines. Infection with C. trachomatis in those patients and controls was detected by two methods; assay of anti-chlamydia IgA antibodies level in seminal plasma and detection C. trachomatis deoxyribonucleic acid (DNA) by real-time polymerase chain reaction (RT-PCR) technology.

RESULTS

Positive detection of anti-Chlamydia IgA antibody was found in 28 (14%) patients and in 6 (9.2%) controls. Positive detection of C. trachomatis-cryptic plasmid gene was found in 15 (7.5%) patients and in zero of controls. Detection of anti-chlamydia IgA by enzyme-linked immunosorbent assay (ELISA) has a sensitivity of 100% and specificity of 92.97%. There were significant associations between C. trachomatis infection and asthenozoospermia (P = .05), and abnormal vitality (P = .003).

CONCLUSION

C. trachomatis infection adversely affects the fertility potential in males because of its effect on the motility and vitality of sperms. We can rely on the detection of anti-chlamydia IgA antibodies in seminal plasma as a rapid sensitive diagnostic test for the detection of C. trachomatis infection.

Study of Semen Quality, Reproductive Hormone Levels, and Lipid Levels in Men From Arkhangelsk, a City in North of European Russia

Male populations in the European North of Russia have not previously been investigated for semen quality. The aim of this study was to evaluate semen parameters, reproductive hormone levels, and lipid levels in volunteers from the general urban population of the European North of Russia, to compare the data published for men from the neighboring Northern or Eastern European countries, and to evaluate associations between sperm quality and serum hormonal and lipid levels. Ninety-nine volunteers aged 23-63 years residing in the city of Archangelsk were enrolled in the study. All men had blood samples drawn and completed a questionnaire concerning their health status and lifestyle; 90 men delivered semen samples. The medians for semen volume, sperm concentration, progressive motility, and normal morphology were 3.0 ml, 42.12 million/ml, 43.8%, and 6.5%, respectively. Sperm parameters below normal threshold values were found in 38.9% of participants. It seems that the sperm quality in our study group was slightly worse than in men from Finland, Norway, Sweden, or Estonia, but very similar to that in men from Denmark or Poland. The significant negative correlations of luteinizing hormone levels and positive correlations of inhibin B levels with sperm concentration and progressive motility were revealed. Higher levels of luteinizing hormone and lower levels of inhibin B were found in participants with impaired compared to normal sperm quality. No reliable links were found between serum total cholesterol, triglyceride, high and low-density lipoprotein cholesterol, and semen parameters.

Low protein diet and methyl-donor supplements modify testicular physiology in mice

The link between male diet and sperm quality has received significant investigation. However, the impact diet and dietary supplements have on the testicular environment has been examined to a lesser extent. Here, we establish the impact of a sub-optimal low protein diet (LPD) on testicular morphology, apoptosis and serum fatty acid profiles. Furthermore, we define whether supplementing a LPD with specific methyl donors abrogates any detrimental effects of the LPD. Male C57BL6 mice were fed either a control normal protein diet (NPD; 18% protein; n = 8), an isocaloric LPD (LPD; 9% protein; n = 8) or an LPD supplemented with methyl donors (MD-LPD; choline chloride, betaine, methionine, folic acid, vitamin B12; n = 8) for a minimum of 7 weeks. Analysis of male serum fatty acid profiles by gas chromatography revealed elevated levels of saturated fatty acids and lower levels of mono- and polyunsaturated fatty acids in MD-LPD males when compared to NPD and/or LPD males. Testes of LPD males displayed larger seminiferous tubule cross section area when compared to NPD and MD-LPD males, while MD-LPD tubules displayed a larger luminal area. Furthermore, TUNNEL staining revealed LPD males possessed a reduced number of tubules positive for apoptosis, while gene expression analysis showed MD-LPD testes displayed decreased expression of the pro-apoptotic genes Bax, Csap1 and Fas when compared to NPD males. Finally, testes from MD-LPD males displayed a reduced telomere length but increased telomerase activity. These data reveal the significance of sub-optimal nutrition for paternal metabolic and reproductive physiology.

A narrative review of urinary phospholipids: from biochemical aspect towards clinical application

As a newly emerged discipline, lipidomic studies have focused on the comprehensive characterization and quantification of lipids in a given biological system, which has remarkably advanced in recent years owing to the rapid development of analytical techniques, especially mass spectrometry. Among diverse lipid classes, phospholipids, which have fundamental roles in the formation of cellular membranes, signaling processes, and bioenergetics have gained momentum in several fields of research. The altered composition, concentration, spatial distribution, and metabolism of phospholipids in cells, tissues, and body fluids have been elucidated in various human diseases such as cancer, inflammation, as well as cardiovascular and metabolic disorders. Among the different kinds of phospholipid sources in the human body, urine has not been extensively investigated in recent years owing to the extremely low concentrations of phospholipids and high levels of salts and other contaminants, which can interfere with precise detection. However, with profound advances and rapid expansion in analytical methods, urinary phospholipids have attracted increasing attention in current biomedical research as urine is an easily available source for the discovery of noninvasive biomarkers. In this review, we provide an overview of urinary phospholipids, including their biochemical aspects and clinical applications, aimed at promoting this field of research.

Adverse effects of metabolic disorders in childhood on adult reproductive function and fertility in the male

Over the last 50 years, there has been a steady decline in fertility rates in humans, which has occurred in parallel with an increasing incidence of obesity and metabolic disorders. The potential impact of these disorders and plausible mechanisms by which they negatively influence male reproduction are only partly understood and published data are often controversial. Obesity is one of the most important health challenges worldwide and is becoming more prevalent in children and adolescents. Obesity, the metabolic syndrome and related co-morbidities can lead to impaired male reproductive function, including adverse effects on spermatogenesis and steroidogenesis as illustrated by reduced sperm number and quality, decreased testosterone levels and elevated inflammatory markers. The incidence of diabetes mellitus type I is also dramatically increasing and may negatively impact spermatogenesis and testicular function, resulting in decreased serum testosterone and epididymal weight. In this review, we summarize and discuss the effects of metabolic diseases that typically develop during childhood and adolescence on later reproductive function and fertility. While impact on reproductive health is likely observed in both sexes, we have chosen to focus on the male in the current review. Specifically, we illustrate adverse effects of obesity, type 1 diabetes, the metabolic syndrome and insulin resistance on sperm function and testosterone metabolism. Identification of pathophysiological mechanisms during childhood may open up new avenues for early prevention and treatment resulting in better reproductive outcomes and improved fertility rates during adulthood.

Association of the serum metabolomic profile by nuclear magnetic resonance spectroscopy with sperm parameters: a cross-sectional study of 325 men

OBJECTIVE

To determine whether 155 circulating metabolic measures relevant to lifestyle and metabolic health are associated with sperm parameters, as measured by concentration, motility, and total motile sperm count (TMSC).

STUDY DESIGN

Cross sectional.

SETTING

University hospital.

PATIENT(S)

Three hundred twenty-five men prospectively recruited between April 1, 2017 and March 31, 2019.

INTERVENTION(S)

Detailed demographic, lifestyle, fertility, medical history, and semen analysis with quantification of nonfasting serum lipids, lipoprotein subclasses, and low-molecular weight metabolites (including amino acids, glycolysis, and inflammatory markers) by nuclear magnetic resonance (NMR) spectroscopy.

MAIN OUTCOME MEASURE(S)

Association of serum metabolic profiles with sperm parameters.

RESULT(S)

The age of the participants was mean 37.2 years, with a median sperm concentration of 35 million/mL and median motility of 53%. Of these men, 76% had a TMSC >15 million, 10% had 5-15 million, and 14% had <5 million. In both univariate and confounder adjusted analyses, an extensive range of lipids and lipoproteins, glycolysis-related metabolites, amino acids, ketone bodies, creatinine, or albumin showed no strong statistically significant association with sperm concentration, motility, or the odds of having a reduced or low TMSC. Higher levels of glycolysis metabolites and ketone bodies were associated with an increased odds of TMSC <15 million compared with ≥15 million (odds ratios of ∼1.2-1.3), and several lipids/lipoprotein concentrations appeared to protect against very low TMSC (<5 million compared with ≥5 million) with odds ratios of ∼0.8 or greater.

CONCLUSION(S)

Several metabolites exhibited potentially clinically relevant strength of association with the odds of a low TMSC and warrant replication.

Impact of body mass index and metabolic syndrome on sperm DNA fragmentation in males from infertile couples: A cross-sectional study from Vietnam

Objectives

This study investigated the relationship between body mass index (BMI) and metabolic syndrome on sperm DNA fragmentation (SDF) in males from infertile couples.

Methods

This cross-sectional study was performed from September 2018 to September 2019 at the Hue Center for Reproductive Endocrinology and Infertility (HUECREI), Vietnam. The study included men from couples with at least one year of infertility, who were subjected to semen analysis and SDF assay (Halosperm). We also performed a 2-h oral glucose tolerance test and measured lipidemia. Metabolic syndrome (MetS) was defined based on the NHLBI/AHA-ATP III guidelines.

Results

The mean age of the patients was 35.26 ± 5.87 years and 53.8% of them had a BMI ≥23.0 kg/m². The DNA fragmentation index was significantly associated with overweight (p = 0.024). Men without MetS had a higher rate of big halos and a lower rate of small halos, no halos, and degraded semen compared to that in men with MetS, but the differences were not significant (p > 0.05). By performing multivariable analysis, we found that the SDF value was significantly different among the two groups with either overweight or normal weight.

Conclusion

In males from infertile couples with a relatively young mean age, BMI can be an independent indicator for SDF. MetS thus has a significant role in the development of sperm DNA fragmentation, at least in overweight individuals; it should thus be assessed under the scope of BMI, for better/earlier detection of increased SDF.

•

Sperm DNA fragmentation recently appears to be a good marker for male reproductive potential.

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BMI can be an independent indicator for increasing SDF.

•

MetS has a significant role in the development of SDF, at least in overweight individuals.

Metabolic syndrome and semen quality in adult population

BACKGROUND

Male obesity is suggested to impact negatively on male fertility and semen quality in numerous studies. However, previous literatures regarding health effects of the metabolic syndrome (MetS) on semen quality are rare and inconsistent. The aim of this study is to investigate the relationship between MetS and sperm parameters in a Taiwanese reproductive-age male population.

METHODS

A total of 8395 men who attended a private medical screening program in Taiwan from 2010 to 2016 were included in this cross-sectional study. Semen analysis was assessed in accordance with the WHO guidelines and included sperm concentration, total motility, progressive motility, and morphology. MetS was defined by the modified National Cholesterol Education Program Third Adult Treatment Panel (NCEP ATP III) criteria with the Asian cutoff for waist circumference (WC). The associations between MetS and semen analysis were examined by multivariable linear regressions.

RESULTS

After fully adjusting for pertinent covariables, MetS was significantly associated with a reduced percentage of sperm normal morphology. Blood pressure, WC, and serum glucose had a significantly negative association with sperm normal morphology. Individuals with an increased number of MetS components had a closer association with reduced sperm progressive motility and the percentage of normal morphology.

CONCLUSION

MetS and its components exhibited deleterious effects on semen quality among reproductive-age men. Further studies are warranted to explore these pathophysiologic relationship and underlying mechanisms.

Male Infertility and Somatic Health

Somatic health is associated with male infertility; potential links between infertility and health may arise from genetic, developmental, and lifestyle factors. Studies have explored possible connections between male infertility and oncologic, cardiovascular, metabolic, chronic, and autoimmune diseases. Male infertility also may be a predictor of hospitalization and mortality. Additional research is required to elucidate the mechanisms by which male infertility affects overall health.

Comprehensive men's health and male infertility

There is increasing evidence that male infertility may be a harbinger of comorbid medical illness. Existing studies have shed light on associations between infertility and the prevalence of cardiovascular, metabolic, and oncologic disease, along with rates of hospitalization and overall mortality. Although theorized mechanisms include genetic, developmental, and behavioral precipitants, the exact nature of these associations remains unclear and warrants further investigation.

Maternal and postnatal high-fat diets with high ω6 : ω3 ratios affect the reproductive performance of male offspring in the mouse

High-fat diets (HFDs) are an acknowledged risk factor for male subfertility, but the underlying mechanisms remain unclear. In the present study we compared the effects of two HFDs with different ω6:ω3 ratios, one enriched with soy oil (SOD; ω6:ω3=9.62) and another enriched with sunflower oil (SFOD; ω6:ω3=51.55), with those of a commercial diet (CD; ω6:ω3=19.87), supplied from pregnancy to adulthood, on morphometric parameters and reproductive performance in adult male mice (recommended ω6:ω3 for rodents=1-6). Bodyweight was significantly higher in the SFOD than CD group, and relative testicular weight was significantly lower in the SFOD than the other two groups. SFOD altered sperm performance: it reduced sperm viability (mean±s.e.m.; 76.00±1.35% vs 82.50±1.45% and 80.63±1.00% in the SFOD vs CD and SOD groups respectively; P<0.05) and increased the percentage of immature spermatozoa (71.88±7.17% vs 51.38±5.87% and 48.00±5.72% in the SFOD vs CD and SOD groups respectively; P<0.05). The epididymal ω6:ω3 ratio was higher in the SFOD versus CD and SOD groups, whereas the unsaturation index was higher in the SOD and SFOD groups than in CD group. Sperm membrane integrity was diminished in both the SOD and SFOD groups, but there was no difference in sperm reactive oxygen species production in these two groups compared with the CD group. The fertilisation rate was lower in the SFOD compared with the CD and SOD groups. In conclusion, although both HFDs affected sperm quality, the fertilising ability was more altered by the excessive dietary ω6:ω3 ratio than by the net ω6 content.

Impairment of sperm maturation and capacitation due to diet-dependent cholesterol overload

BACKGROUND

Lipid metabolic disorders (dyslipidemia) are constantly increasing in occidental societies and lead to the development of pathologies such as obesity, diabetes, and metabolic syndrome. It has been demonstrated that dyslipidemia can alter the reproductive function. Animal models have recently been used to show that the offspring of dyslipidemic males could also develop such pathologies and that the transgenerational transmission involved post-testicular sperm maturation. These data targeted the essential role of male gamete epididymal maturation and its importance for the health of the offspring.

OBJECTIVES

This publication summarizes in the first place experimental data obtained using a mouse model of dyslipidemia-induced post-testicular infertility, knockout mice for the two isoforms of the 'Liver X Receptors' (Lxrα;β^-/- ), the major regulators of cholesterol homeostasis. The impact of a high cholesterol diet (HCD) on the protein YWHAZ (14-3-3 ζ or tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein Zeta) was also investigated in our model.

MATERIALS AND METHODS

In our mouse model, when young fertile Lxrα;β^-/- males aged three months were fed four weeks with a HCD, they developed an epididymal phenotype leading to infertility. The level of sperm YWHAZ was evaluated by Western blot and its tyrosine phosphorylation state by immunoprecipitation followed by Western blot.

RESULTS

Our data revealed that sperm lipid composition and structure were altered, leading to defects of the capacitation-associated signaling pathway. They also showed that both the level and the tyrosine phosphorylation state of YWHAZ were affected by the HCD in sperm cells from Lxrα;β^-/- males.

DISCUSSION AND CONCLUSION

YWHAZ could be a new important regulator of capacitation-associated tyrosine phosphorylation and a marker of dyslipidemia-induced infertility.

Sertoli Cell Function in Young Males with Metabolic Syndrome

CONTEXT

The last few decades have witnessed an alarming increase in the prevalence of the metabolic syndrome (MetS) worldwide including India. Apart from the known risks of MetS in terms of cardiovascular risk and mortality, there is increasing evidence that it also leads to alteration in testicular function and fertility.

AIMS

To assess the presence of hypogonadism and Sertoli cell dysfunction in young adult males with MetS and correlate these parameters with different components of the MetS.

SETTINGS AND DESIGN

Cross-sectional study conducted in the Department of Endocrinology, Gauhati Medical College, a tertiary care hospital in North East India.

SUBJECTS AND METHODS

Young adult males with MetS aged 20-40 years and age-matched healthy males who served as controls were examined clinically. Laboratory investigations done in the fasting state included blood glucose, lipid profile, serum follicle-stimulating hormone (FSH), inhibin B and total testosterone (Te). Semen was collected after 3 days abstinence and analysis done.

STATISTICAL ANALYSIS

Baseline parameters were presented as median and 'Kruskal-Wallis' test was used to compare them. Pearson test and multiple regression analysis were used to assess the correlation and association between variables.

RESULTS

Fifty cases with MetS and 30 controls were included in the study. Subjects with MetS had significantly lower levels of total Te, FSH and inhibin B. They also had significantly lower semen volume, sperm count and total as well as progressive motility. There was a significant negative correlation of waist circumference and positive correlation of inhibin B with total sperm count. A significant negative association of serum triglycerides with semen volume was also found.

CONCLUSION

MetS is a state of hypogonadotropic hypogonadism as reflected by low total Te, FSH and inhibin B levels with semen abnormalities reflecting Sertoli cell dysfunction.

Update on the cellular and molecular aspects of cystic fibrosis transmembrane conductance regulator (CFTR) and male fertility

CFTR protein regulates electrolyte and fluid transport in almost all tissues with exocrine function, including male reproductive tract. Mutation of CFTR gene causes cystic fibrosis (CF), which affects the function of several organs, and impairs male fertility. The role of CFTR protein in different compartments of male reproductive tract (testis, epididymis, sperm) as well as an impact of CFTR mutation(s) on male fertility phenotype is discussed in relation with the choice of optimal technique for Assisted Reproductive Techniques (ART) management.

Role of reactive oxygen species-total antioxidant capacity status in Telfairia occidentalis leaves-associated spermatoprotective effect: a pointer to fatty acids benefit

Background The present study used reactive oxygen species (ROS)-total antioxidant capacity (TAC) score to understand the role of redox status on the effect of Telfairia occidentalis (TO) on testicular parameters. The fatty acids (FAs) components of methanol extract of TO (METO) and its fractions were also identified with gas chromatography-mass spectrometry. Methods A total of 66 male Wistar rats were randomly divided in a blinded fashion into six oral treatment groups as follows: group I (control, n=6) received 10% ethanol (vehicle for TO administration). Groups II to VI (n=12 rats each) were subdivided into two treatment subgroups (n=6 each) that received 200 mg/kg and 600 mg/kg of METO and its chloroform, petroleum ether, acetone, and ethanol fractions, respectively. All treatments lasted for 30 days. Results The major FAs detected in TO were myristic, palmitic, oleic, linoleic, linolenic, and stearic acids including their esters. Both doses of METO and its fractions increased the semen parameters, TAC and ROS-TAC scores but decreased the ROS when compared with control. Conclusions Using the ROS-TAC score, this study suggests that TO-associated improvement in semen parameters might be partly mediated by a reduction in free radical generation, and that the FAs present in TO might be involved in its spermatoprotective effect.

Serum lipid profiles are associated with semen quality

We aimed to explore the associations between different lipid profiles and semen quality in a large-scale general male population. Sperm concentration, total sperm motility, progressive motility, and normal sperm morphology of total 7601 participants were recorded. The association of these semen parameters with the triglyceride, total cholesterol, high-density lipoprotein, low-density lipoprotein, and very low-density lipoprotein of serum lipid profiles was analyzed. Sperm concentration was statistically positively correlated with triglyceride and very low-density lipoprotein (adjusted P = 0.001 and P = 0.005, respectively). Total sperm motility and progressive motility were statistically increased with increasing low-density lipoprotein and cholesterol levels (both adjusted P = 0.008 and P < 0.001, respectively). The similar J-shaped associations (high-low-low-high) were noted between individual lipid profile and normal sperm morphology, especially low-density lipoprotein and cholesterol with statistical significance (adjusted P = 0.017 and P = 0.021, respectively). The prevalence of abnormal total sperm motility and progressive motility was decreased in participants with high levels of cholesterol (P = 0.008 and P = 0.019, respectively), and the reverse J-shaped associations (low-high-high-low) were noted between high-density lipoprotein, triglyceride, very low-density lipoprotein, and the prevalence of abnormal normal sperm morphology (P = 0.010, P = 0.037, and P = 0.025, respectively). A high cholesterol level was associated with better sperm motility. Similar J-shaped associations were noted between all lipid profiles and normal sperm morphology; meanwhile, the reverse J-shaped trends were identified between them and abnormal normal sperm morphology prevalence.

The Effect of Omega-3 Fatty Acids, EPA, and/or DHA on Male Infertility: A Systematic Review and Meta-analysis

The objective was to evaluate the effect of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) on sperm parameters including total sperm concentration, sperm motility, sperm DHA, and seminal plasma DHA concentration in infertile men. The literature search was conducted in PubMed, Google Scholar, and Scopus from January 1, 1990 to December 20, 2017. The systematic review and meta-analysis were based on randomized controlled trials in infertile men with DHA or EPA treatments, either alone or in combination with other micronutrients. Three studies met the inclusion criteria: 147 patients in the intervention group and 143 patients in the control group. The analysis showed that omega-3 treatments significantly increased the sperm motility (RR 5.82, 95% CI [2.91, 8.72], p <. 0001, I² = 76%) and seminal DHA concentration (RR 1.61, 95% CI [0.15, 3.07], p =. 03, I² = 98%). Compared with the controls, the interventions did not affect the sperm concentration (RR 0.31, 95% CI [-8.13, 8.76], p =. 94, I² = 95%) or sperm DHA (RR 0.50, 95% CI [-4.17, 5.16], p =. 83, I² = 99%). The observed heterogeneity may be due to administration period and dosage of omega-3 fatty acids across the studies. Funnel plot shows no evidence of publication bias. This meta-analysis indicates that supplementing infertile men with omega-3 fatty acids resulted in a significant improvement in sperm motility and concentration of DHA in seminal plasma.

Obesity, a serious etiologic factor for male subfertility in modern society

Obesity, defined as excessive accumulation of fat in adipose tissue, is a metabolic disorder resulting from behavioral, environmental and heritable causes. Obesity increases the risks of hypertension, diabetes, cardiovascular disease, sleep apnea, respiratory problems, osteoarthritis and cancer. Meanwhile, the negative impact of obesity on male reproduction is gradually recognized. According to the clinical investigations and animal experiments, obesity is correlated with reductions in sperm concentration and motility, increase in sperm DNA damage and changes in reproductive hormones. Several mechanisms can elucidate the effects of obesity on sperm functions and male subfertility, i.e., the excessive conversion of androgens into estrogens in redundant adipose tissue causes sexual hormone imbalance, subsequently resulting in hypogonadism. Secondly, adipokines produced by adipose tissue induce severe inflammation and oxidative stress in male reproductive tract, directly impairing testicular and epididymal tissues. Moreover, increased scrotal adiposity leads to increase gonadal heat, continuously hurting spermatogenesis. Therefore, obesity alters the systematic and regional environment crucial for spermatogenesis in testis and sperm maturation in epididymis, and finally results in poor sperm quality including decreased sperm motility, abnormal sperm morphology and acrosome reaction, changed membrane lipids and increased DNA damage. Furthermore, recent studies indicate that epigenetic changes may be a consequence of increased adiposity. A major effort to identify epigenetic determinants of obesity revealed that sperm DNA methylation and non-coding RNA modification are associated with BMI changes and proposed to inherit metabolic comorbidities across generations. This review will explain how obesity-related changes in males to influence sperm function and male fertility as well.

Genetic loci associated with coronary artery disease harbor evidence of selection and antagonistic pleiotropy

Traditional genome-wide scans for positive selection have mainly uncovered selective sweeps associated with monogenic traits. While selection on quantitative traits is much more common, very few signals have been detected because of their polygenic nature. We searched for positive selection signals underlying coronary artery disease (CAD) in worldwide populations, using novel approaches to quantify relationships between polygenic selection signals and CAD genetic risk. We identified new candidate adaptive loci that appear to have been directly modified by disease pressures given their significant associations with CAD genetic risk. These candidates were all uniquely and consistently associated with many different male and female reproductive traits suggesting selection may have also targeted these because of their direct effects on fitness. We found that CAD loci are significantly enriched for lifetime reproductive success relative to the rest of the human genome, with evidence that the relationship between CAD and lifetime reproductive success is antagonistic. This supports the presence of antagonistic-pleiotropic tradeoffs on CAD loci and provides a novel explanation for the maintenance and high prevalence of CAD in modern humans. Lastly, we found that positive selection more often targeted CAD gene regulatory variants using HapMap3 lymphoblastoid cell lines, which further highlights the unique biological significance of candidate adaptive loci underlying CAD. Our study provides a novel approach for detecting selection on polygenic traits and evidence that modern human genomes have evolved in response to CAD-induced selection pressures and other early-life traits sharing pleiotropic links with CAD.

The Relationship between the Amount of Saturated Fat Intake and Semen Quality in Men

Introduction:

Infertility in men is one of the current problems of human society. Some studies suggest that the metabolic status of a man, including cholesterol intake, closely correlates with sperm function. The aim of this study was to evaluate the correlation between saturated fat intake and semen quality among men referring to the Isfahan Fertility and Infertility Center, Iran.

Materials and Methods:

This cross-sectional study was conducted on all men who referred to the Isfahan Fertility and Infertility Center. The study population consisted of 120 men selected through simple random sampling. The data collection tool consisted of a two-part questionnaire including a demographic and anthropometric characteristics form and the Food Frequency Questionnaire (FFQ). The FFQ consists of 168 items that assess food and nutrient intake for 3 months. The reliability and validity of the instruments were confirmed in previous studies. Semen analysis was performed using computer-aided semen analysis (CASA) method. Descriptive statistics and logistic regression test were used to analyze the data.

Results:

Results showed that the chances of having semen volume of higher than 1.5 ml (normal volume) increased by 27.5% for every 1 g increase in total fat (CI: 1.11–1.46) (P = 0.001) and reduced 38% for every 1 g increase in saturated fat (CI: 0.42–0.90, P = 0.010). No association was found between semen quality and intake of dietary fats.

Conclusions:

Based on the findings of this study and the prevalence of infertility in recent decades, changes in diet and saturated fatty acids intake may improve semen quality.

Hypertension and Male Fertility

As the age of paternity rises in the developed world, issues of chronic disease may affect prospective fathers. Given the high prevalence of hypertension, researchers have begun to explore the relationship between hypertensive disease and male fertility. The current literature suggests an association between hypertension and semen quality. The use of various antihypertensive medications has also been linked to impaired semen parameters, making it difficult to discern whether the association exists with hypertension or its treatment. Further investigation is warranted to determine whether the observed associations are causal.

Men's knowledge of their own fertility: a population-based survey examining the awareness of factors that are associated with male infertility

STUDY QUESTION

How knowledgeable are men about the medical, environmental and psychological factors that are associated with male infertility?

SUMMARY ANSWER

Men, across most demographic groups, have limited knowledge of the various factors that are associated with male infertility.

WHAT IS KNOWN ALREADY

Few surveys have focused on men's knowledge of their own fertility. Studies of both men and women have found that men are comparatively less knowledgeable about issues of fertility and reproductive health.

STUDY DESIGN, SIZE, DURATION

A regionally representative sample of Canadian men completed a web-based survey of male fertility and reproductive health, over a 2-month period in 2015.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Men, aged 18-50 years, were recruited for the study. There were 701 male participants, with a mean age of 34.1 years. Each participant was asked to identify factors associated with male infertility; fertility knowledge was assessed through two open-ended questions and a comprehensive list of risk factors and attendant health issues.

MAIN RESULTS AND THE ROLE OF CHANCE

Men were only able to identify 51% of the risk factors and 45% of the health issues associated with male infertility. Men were most aware of the modifiable risk factors for infertility (e.g. sexually transmitted infections, smoking cigarettes), relative to their knowledge of fixed risk factors (e.g. delayed puberty, size of testicles) and the attendant health issues (e.g. cardiovascular disease, diabetes). The overall level of fertility knowledge did not vary by most demographic characteristics (e.g. age, education, employment, income), though men from ethnic minority groups displayed moderately greater awareness. Additionally, younger men, those with lower incomes and those who had no desire to have future biological children were more likely to identify themselves as unaware of associations with infertility in the open-ended questions. Self-reported knowledge was significantly associated with higher overall knowledge scores. More than half of the sample expressed an interest in obtaining information about male fertility and reproductive health, with the majority of these men indicating that medical professionals and online sources were their preferred methods for receiving information.

LIMITATIONS, REASONS FOR CAUTION

Participants were self-selected and required to have Internet access in order to participate. This may affect the generalizability of results.

WIDER IMPLICATIONS OF THE FINDINGS

Previous studies of fertility knowledge have either omitted men from their samples or when men have been included, they were asked about general fertility or women's fertility. This is the first large-scale survey that focuses solely on men's knowledge of male fertility. Insight into the areas where men's knowledge may be lacking can inform strategies for disseminating fertility-related information and improving men's fertility awareness. Public health initiatives should tailor campaigns to educate men about the lesser known associations with male infertility, particularly those that are most prevalent and preventable through lifestyle modification.

STUDY FUNDING/COMPETING INTERESTS

The study was funded by a grant from CIHR TE1-138296. No competing interests.

Diabetes, medical comorbidities and couple fecundity

STUDY QUESTION

What is the relationship between couple's health and fecundity in a preconception cohort?

SUMMARY ANSWER

Somatic health may impact fecundity in men and women as couples whose male partner had diabetes or whose female partner had two or more medical conditions had a longer time-to-pregnancy (TTP).

WHAT IS ALREADY KNOWN

The impact of somatic health on human fecundity is hypothesized given the reported declines in spermatogenesis and ovulation among individuals with certain medical comorbidities.

STUDY DESIGN, SIZE, DURATION

A population-based prospective cohort study recruiting couples from 16 counties in Michigan and Texas (2005-2009) using sampling frameworks allowing for identification of couples planning pregnancy in the near future. Five hundred and one couples desiring pregnancy and discontinuing contraception were followed-up for 12 months or until a human chorionic gonadotropin pregnancy was detected.

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

In all, 33 (21.4%) female and 41 (26.6%) male partners had medical conditions at baseline.

MAIN RESULTS AND THE ROLE OF CHANCE

Couples' medical comorbidity was associated with pregnancy status. Diabetes in either partner was associated with diminished fecundity, as measured by a longer TTP. Specifically, fecundability odds ratios (FORs) were below 1, indicating a longer TTP, for male partners with diabetes (0.35, 95% confidence interval (CI): 0.14-0.86) even in adjusted models (0.35, 95% CI: 0.13-0.88). Female partners with diabetes had comparable reductions in FORs; however, the analyses did not reach statistical significance (0.26, 95% CI: 0.03-1.98). Female partners with two or more medical conditions had a significantly longer TTP compared with women with no health problems (0.36, 95% CI: 0.14-0.92). Importantly, the presence of medical conditions was not associated with sexual frequency. We cannot rule out residual confounding, Type 2 errors for less prevalent medical conditions, or chance findings in light of the multiple comparisons made in the analysis.

LIMITATIONS, REASONS FOR CAUTION

The findings require cautious interpretation given that medical diagnoses are subject to possible reporting errors, although we are unaware of any potential biases that may have been introduced, as participants were unaware of how long it would take to become pregnant upon enrollment.

WIDER IMPLICATIONS OF THE FINDINGS

The current report suggests a relationship between male and female diabetes and fecundity, and possibly somatic health more globally. Moreover, while the mechanism is uncertain, if corroborated, our data suggest that early evaluation and treatment may be warranted for diabetics prior to attempting to conceive.

STUDY FUNDING/COMPETING INTERESTS

Intramural research of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (Contract nos. #N01-HD-3-3355, N01-HD-3-3356 and N01-HD-3-3358). The authors have no conflicts of interest to declare.

Does advancing male age influence the expression levels and localisation patterns of phospholipase C zeta (PLCζ) in human sperm?

Socio-economic factors have led to an increasing trend for couples to delay parenthood. However, advancing age exerts detrimental effects upon gametes which can have serious consequences upon embryo viability. While such effects are well documented for the oocyte, relatively little is known with regard to the sperm. One fundamental role of sperm is to activate the oocyte at fertilisation, a process initiated by phospholipase C zeta (PLCζ), a sperm-specific protein. While PLCζ deficiency can lead to oocyte activation deficiency and infertility, it is currently unknown whether the expression or function of PLCζ is compromised by advancing male age. Here, we evaluate sperm motility and the proportion of sperm expressing PLCζ in 71 males (22–54 years; 44 fertile controls and 27 infertile patients), along with total levels and localisation patterns of PLCζ within the sperm head. Three different statistical approaches were deployed with male age considered both as a categorical and a continuous factor. While progressive motility was negatively correlated with male age, all three statistical models concurred that no PLCζ–related parameter was associated with male age, suggesting that advancing male age is unlikely to cause problems in terms of the sperm’s fundamental ability to activate an oocyte.

Male obesity and subfertility, is it really about increased adiposity?

The prevalence of overweight and obesity in reproductive-aged men is increasing worldwide, with >70% of men >18 years classified as overweight or obese in some western nations. Male obesity is associated with male subfertility, impairing sex hormones, reducing sperm counts, increasing oxidative sperm DNA damage and changing the epigenetic status of sperm. These changes to sperm function as a result of obesity, are further associated with impaired embryo development, reduced live birth rates and increased miscarriage rates in humans. Animal models have suggested that these adverse reproductive effects can be transmitted to the offspring; suggesting that men's health at conception may affect the health of their children. In addition to higher adiposity, male obesity is associated with comorbidities, including metabolic syndrome, hypercholesterolemia, hyperleptinemia and a pro-inflammatory state, all which have independently been linked with male subfertility. Taken together, these findings suggest that the effects of male obesity on fertility are likely multifactorial, with associated comorbidities also influencing sperm, pregnancy and subsequent child health.

Premature coronary heart disease and autosomal dominant hypercholesterolemia: Increased risk in women with LDLR mutations

BACKGROUND

For patients with autosomal dominant hypercholesterolemia (ADH), it remains unclear whether differences exist in the risk of premature coronary heart disease (CHD) between patients with confirmed mutations in low-density lipoprotein receptor (LDLR) vs those without detectable mutations.

OBJECTIVE

This study sought to assess the risk of premature CHD in ADH patients with mutations in LDLR (referred to as familial hypercholesterolemia [FH]) vs those without detectable mutations (unexplained ADH), stratified by sex.

METHODS

Comparative study of premature CHD in a multiethnic cohort of 111 men and 165 women meeting adult Simon-Broome criteria for ADH.

RESULTS

Women with FH (n = 51) had an increased risk of premature CHD compared with unexplained ADH women (n = 111; hazard ratio [HR], 2.74; 95% confidence interval, 1.40-5.34; P = .003) even after adjustment for lipid levels and traditional CHD risk factors (HR, 2.53 [1.10-5.83]; P = .005). Men with FH (n = 42), in contrast, had a similar risk of premature CHD when compared with unexplained ADH men (n = 66; unadjusted: HR, 1.48 [0.84-2.63]; P = .18; adjusted: HR, 1.04 [0.46-2.37]; P = .72). To address whether mutation status provides additional information beyond LDL-cholesterol level, we analyzed premature CHD risk for FH vs unexplained ADH at various percentiles of LDL-cholesterol: the risk ratios were significant for women at 25th percentile (HR, 4.90 [1.69-14.19]) and 50th percentile (HR, 3.44 [1.42-8.32]) but not at 75th percentile (HR, 1.99 [0.95-4.17]), and were not significant for men at any percentile.

CONCLUSIONS

Our findings suggest that genetic confirmation of ADH may be important to identify patient's risk of CHD, especially for female LDLR mutation carriers.

Urinary Phytoestrogens Are Associated with Subtle Indicators of Semen Quality among Male Partners of Couples Desiring Pregnancy

BACKGROUND

Phytoestrogens have been associated with subtle hormonal changes, although effects on male fecundity are largely unknown.

OBJECTIVE

We evaluated associations between male urinary phytoestrogen (isoflavone and lignan) concentrations and semen quality.

METHODS

This study was a prospective cohort study of 501 male partners of couples desiring pregnancy and discontinuing contraception. Each participant provided up to 2 semen samples that were analyzed for 35 semen quality endpoints the following day. Linear mixed-effects models were used to estimate associations between baseline urinary phytoestrogen concentrations and semen quality parameters, adjusted for age, body mass index (BMI), research site, and serum lipid and cotinine concentrations.

RESULTS

Most associations between urinary phytoestrogens and semen quality parameters were null. However, select individual phytoestrogens were associated with semen quality parameters, with associations dependent on the class of phytoestrogens and modified by BMI. Specifically, genistein and daidzein were associated with a lower percentage of normal sperm and increased abnormalities in semen morphology, with reduced associations observed as BMI increased (P < 0.05) [percentages (95% CIs) of normal morphology by WHO traditional criteria: genistein, main effect: -5.61% (-9.42%, -1.79%); interaction: 0.19% (0.06%, 0.31%) per log unit increase; daidzein, main effect: -5.35% (-9.36%, -1.34%); interaction: 0.18% (0.05%, 0.32%) per log unit increase]. Enterolactone was associated with fewer abnormalities in semen morphometry and morphology and decreased DNA fragmentation, with reduced associations observed as BMI increased (P < 0.05) [percentages (95% CIs) of abnormalities in the neck and midpiece: enterolactone, main effect: -3.35% (-6.51%, -0.19%); interaction: 0.11% (0.01%, 0.21%) per log unit increase].

CONCLUSIONS

These results suggest that male urinary phytoestrogen concentrations characteristic of the US population may be associated with subtle indicators of male fecundity and semen quality but were not associated with couple fecundity.