Seminal fluid and fertility in women

How sperm protects itself: A journey in the female reproductive system

Sperm must pass a complex route in the female reproductive tract (FRT) to reach the fertilization site and join the oocyte. Thus, it should employ several mechanisms to survive against the female immune system, fertilize the oocyte, and successfully transmit paternal genes to the next generation. In addition to self-protection, sperm may be involved in the immune tolerance to the developing embryo and regulating the FRT for embryo implantation and subsequent pregnancy. Hence, this review intends to summarize the mechanisms that protect sperm in the FRT: including immunomodulatory factors that are carried by seminal plasma, cell-to-cell and molecular interaction of sperm with epithelial and immune cells of the FRT, high regulated secretions of inflammatory factors such as cytokines, chemokines, and growth factors, inducing immune tolerance to paternal antigens, and specialized expression of cell receptors and binding proteins. In most of these events sperm induces the FRT to protect itself by modulating immune responses for its own benefit. However, not all sperm in the semen are able to trigger the survival mechanisms and only high-quality sperm will overcome this challenge. A clear understanding of the molecular mechanisms that maintain sperm viability and function in the FRT can lead to new knowledge about infertility etiology and a new approach in assisted reproductive technologies for the preparation and selection of the best sperm based on the criteria that physiologically happen in-vivo.

Innate and adaptive immune dysregulation in women with recurrent implantation failure

Recurrent implantation failure (RIF) is a condition where a woman fails to obtain pregnancy after multiple embryo transfer cycles, even with superior-quality blastocysts. There are various factors that can contribute to RIF, including immunologic disturbances. The immune system is extremely important during pregnancy. Immune cells such as T cells, B cells, natural killer (NK) cells, and macrophages (MQ) are present in the female reproductive tract and are accountable for regulating the immune response to invading pathogens and maintaining tissue homeostasis. Dysregulation of these immune cells can lead to inflammation, which can impair fertility. One of the most common immunological disturbances observed in RIF is an altered Th1/Th2 ratio, along with changes in NK cell and macrophage numbers. In addition, the presence of some antibodies, such as anti-ovarian antibodies, can also contribute to RIF. Interleukins have been implicated in the development of an inflammatory response that can interfere with successful embryo implantation. As a result, a comprehensive understanding of immunological compartments in RIF women could assist us in determining the immunological origins of this disease. We will discuss immunological factors that might contribute to RIF etiology, including cellular and molecular components.

Beyond Immune Balance: The Pivotal Role of Decidual Regulatory T Cells in Unexplained Recurrent Spontaneous Abortion

Recurrent spontaneous abortion (RSA) is defined as two or more consecutive pregnancy failures, which brings tremendous stress to women of childbearing age and seriously affects family well-being. However, the reason in about 50% of cases remains unknown and is defined as unexplained recurrent spontaneous abortion (URSA). The immunological perspective in URSA has attracted widespread attention in recent years. The embryo is regarded as a semi-allogeneic graft to the mother. A successful pregnancy requires transition to an immune environment conducive to embryo survival at the maternal-fetal interface. As an important member of regulatory immunity, regulatory T (Treg) cells play a key role in regulating immune tolerance at the maternal-fetal interface. This review will focus on the phenotypic plasticity and lineage stability of Treg cells to illustrate its relationship with URSA.

In vivo effect of vaginal seminal plasma application on the human endometrial transcriptome: a randomized controlled trial

Studies in humans and animals suggest that seminal plasma, the acellular seminal fluid component, stimulates the endometrium to promote immune tolerance and facilitate implantation. We designed a randomized, double-blinded, placebo-controlled trial to investigate changes in the endometrial transcriptomic profile after vaginal application of seminal plasma. The study participants were randomized into two groups. Five women received a vaginal application of seminal plasma, and four received a placebo application with saline solution. The application was performed 2 days after HCG-triggered ovulation in an unstimulated cycle. After 5-8 days, an endometrial biopsy was collected to analyze differences in the endometrial transcriptomic profile using microarray analyses. A differential gene expression analysis and a gene set analysis were performed. The gene set enrichment analysis showed a positive enrichment of pathways associated with the immune response, cell viability, proliferation, and cellular movement. Moreover, pathways involved in implantation, embryo development, oocyte maturation, and angiogenesis were positively enriched. The differential gene expression analysis, after adjusting for multiple testing, showed no significantly differentially expressed genes between the two groups. A comparative analysis was also performed with similar studies conducted in other animals or in vitro using human endometrial cells. The comparative analysis showed that the effect of seminal plasma effect on the endometrium is similar in pigs, mice, and in vitro human endometrial cells. The present study provides evidence that seminal plasma might impact the endometrium during the implantation window, with potential to affect endometrial receptivity and embryo development.

The "Bad Father": Paternal Role in Biology of Pregnancy and in Birth Outcome

Pregnancy is generally studied as a biological interaction between a mother and a fetus; however, the father, with his characteristics, lifestyle, genetics, and living environment, is by no means unrelated to the outcome of pregnancy. The half of the fetal genetic heritage of paternal derivation can be decisive in cases of inherited chromosomal disorders, and can be the result of de novo genetic alterations. In addition to the strictly pathological aspects, paternal genetics may transmit thrombophilic traits that affect the implantation and vascular construction of the feto-placental unit, lead to placenta-mediated diseases such as pre-eclampsia and fetal growth retardation, and contribute to the multifactorial genesis of preterm delivery. Biological aspects of immunological tolerance to paternal antigens also appear to be crucial for these pathologies. Finally, this review describes the biological findings by which the environment, exposure to pathogens, lifestyle, and nutritional style of the father affect fetal pathophysiological and epigenetic definition.

Non-monotonic effects of Bisphenol A Dimethacrylate on male mouse reproductive system and fertility leads to impaired conceptive performance

As an estrogenic agent, Bisphenol A Dimethacrylate (Bis-DMA) may incite alterations in both the reproductive tract and the neuroendocrine axis, and thus have the potential to affect the proper development, maturity and conceptive performance in animals. We investigated the consequences of 14 weeks of exposure to different concentrations of Bis-DMA on male mouse conceptive performance. Male mice were exposed to Bis-DMA (0, 0.1 mg/L, 1.0 mg/L or 10 mg/L) via drinking water, and the effects on fertility, reproductive organ weights, reproductive hormone levels, sperm counts and testicular histology were assessed. We clearly demonstrate that prolonged exposure of male mice to Bis-DMA negatively affects fertility and reproduction causing significant reductions in sperm counts, non-monotonic effects on serum LH and testosterone levels, increased seminal vesicle weights, lower number of embryonic implantations and viable fetuses, as well as, increased embryonal resorptions in females mated by Bis-DMA treated males. Furthermore, Bis-DMA caused abnormalities in testicular infrastructure with atrophic seminiferous tubules exhibiting intraepithelial vacuolization and disorganization, loss and shedding of germ cells into the lumen, and presence of apoptotic cells. Our data collectively suggest that Bis-DMA adversely affects male fertility and reproduction by interference with normal hormone signaling in the testis, inducing changes in testicular infrastructure and ultimately leading to impaired reproductive function and fertility.

Intravaginal exposure to seminal plasma after ovum pick-up does not increase live birth rates after in vitro fertilization or intracytoplasmic sperm injection treatment: a double-blind, placebo-controlled randomized trial

OBJECTIVE

To detect whether intravaginal exposure to prepared seminal plasma led to an absolute increase in live birth rate (LBR) after in vitro fertilization (IVF) by 10% compared with placebo. It has been suggested that intravaginal deposition of seminal plasma after ovum pick-up (OPU) for IVF treatment, increases pregnancy and LBRs.

DESIGN

Double-blind, placebo-controlled prospective study. An outcome assessment was made before the type of intervention was unblinded. The outcome data were analyzed according to an intention-to-treat protocol.

SETTING

University Hospital.

PATIENTS

Couples scheduled for an IVF treatment cycle: in total, 792 couples (393 in the seminal plasma group and 399 in the control group) were recruited over a 5-year period of inclusion in a single-center setting.

INTERVENTION

On the day of OPU, the couples were randomized into groups receiving either vaginal deposition of prepared seminal plasma from the partner or saline. Both participants and the physician were blind to the grouping.

MAIN OUTCOME MEASURES

The primary outcome was a live birth (LB). The secondary outcomes were a positive pregnancy test, defined as human chorionic gonadotropin identified in urine 3 weeks after OPU , and clinical pregnancy, defined as an intrauterine viable pregnancy assessed using transvaginal sonography after 5-7 weeks.

RESULTS

In the index group, 35.4% had a positive pregnancy test (relative risk [RR],0.93; 95% confidence interval {CI} 0.78-1.10), 28.8% had a clinical pregnancy (RR 1.00, 95% CI 0.97-1.03), and 26.5% had a LB (RR 0.86; 95% CI 0.70-1.07), adjusted for day of transfer, female age, and number of fertilized oocytes. Corresponding rates in the control group were 37.3%, 33.6%, and 29.8%. No statistically significant differences regarding outcomes between the two intervention groups were found.

CONCLUSION

Prepared seminal plasma applied in the vagina directly after OPU did not increase the rates of LB or clinical pregnancies. The importance of immunological factors to allow the implantation of an embryo is not questioned, but no improvement in the LBRs in IVF treatment by introducing the male partner's prepared seminal plasma after OPU could be found.

CLINICAL TRIAL REGISTRATION NUMBER

Clinicaltrials.gov, ID NCT02716753. Registration date 17 March, 2016, first enrollment November, 2016, completed March, 2023.

NLRP3 inflammasome pathway, the hidden balance in pregnancy: A comprehensive review

The balance of the inflammatory response is indispensable during pregnancy. Inflammasomes are the cytosolic supramolecular protein complexes activated by pattern recognition receptors. These receptors recognize the pathogen and damage/danger-associated molecular patterns. NLRP3 inflammasome complex consists mainly of NLRP3 (leucine-rich repeat-containing and pyrin domain-containing protein 3), a cytosolic sensor molecule, ASC (apoptosis-associated speck-like protein containing a CARD) protein and a cysteine protease pro-caspase-1 as an effector molecule. This complex has a role in producing inflammatory cytokines, interleukin 1 beta and interleukin 18, and inflammasome-dependent programmed cell death pathway pyroptosis. In this review, we focused on and summarised the NLRP3 inflammasome and its roles in normal and pathological pregnancies. The NLRP3 inflammasome pathway influences endometrial receptivity and embryo invasion by inducing epithelial-mesenchymal transition. Abnormal inflammasome activation in the endometrium may adversely affect endometrial receptivity. In addition, NLRP3 inflammasome pathway overactivation may mediate the abnormal inflammatory response at the maternal-fetal interface and be associated with pregnancy complications, such as recurrent implantation failure, pregnancy loss, pre-term birth and pre-eclampsia. Therefore, targeting the NLRP3 inflammasome pathway could develop a new therapeutic approach to prevent the aforementioned pregnancy pathologies.

Antioxidant Genes Variants and Their Association with Sperm DNA Fragmentation

Semen possesses a variety of antioxidant defense mechanisms which protect sperm DNA from the damaging effects of oxidative stress. Correlation between antioxidant genes variants and sperm DNA fragmentation (SDF) level is not sufficiently studied. Therefore, we investigated the association between several single nucleotide polymorphisms (SNPs): CYP1A1 (rs1048943A > G), CYP4F2 (rs2108622G > A), NRF2 (rs6721961C > A), PON1 (rs662A > G), NOS3 (rs1799983G > T), GSTM1 (null), CAT (rs1001179C > T), SOD2 (rs4880A > G), GSTP1 (rs1695A > G), PON2 (rs7493G > C), EPHX2 (rs1042064T > C), and AHR (rs2066853G > A) and elevated SDF. The study employed a case-control design where, the allele and genotype frequencies of the selected SNPs were compared between 75 semen samples with abnormal SDF (the cases) and 75 samples with normal SDF (the controls). DNA was extracted from the semen samples and allele-specific PCR (AS-PCR) was used for genotyping the SNPs. Relevant data were collected from the patients' records et al.-Basma Fertility Center. Suitable statistical tests and multifactorial dimensionality reduction (MDR) test were used to anticipate SNP-SNP interactions. Comparison of semen parameters revealed significant differences between cases and controls in terms of liquefaction time, sperm total motility, and normal form. Genotype frequencies of NOS3 G > T (GT), SOD2 A > G (AA and AG), EPHX2 T > C (CC and CT), and AHR G > A (GA and GG) were significantly different between cases and controls. Allele frequencies of SOD2 (G-allele), and EPHX2 (T-allele) also significantly varied between cases and controls. MDR analysis revealed that the NOS3, SOD2, and EPHX2 SNPs combination has the highest impact on SDF. The study findings suggest that genetic variations in genes involved antioxidant defenses contribute to abnormal SDF.

MiOXSYS® and OxiSperm® II assays appear to provide no clinical utility for determining oxidative stress in human sperm-results from repeated semen collections

BACKGROUND

Oxidative stress in semen contributes up to 80% of all infertility diagnosis. Diagnostics to measure oxidative stress in semen was recently added to the 6th edition WHO methods manual, although diagnostic predictive values need to be interpreted with caution as there are still several research questions yet to be answered.

OBJECTIVES

To determine the natural fluctuations in semen redox indicators (MiOXSYS® and OxiSperm® II) within and between men and their association with markers of sperm oxidative stress.

MATERIALS AND METHODS

Total, 118 repeat semen samples from 31 generally healthy men aged 18-45 years, over 6 months. Standard semen analysis as per 5th WHO manual. Semen redox levels measured via MiOXSYS® and OxiSperm® II. Additional attributes of sperm quality; HBA® binding assay and sperm hyperactivation and oxidative stress; DNA fragmentation (Halo® Sperm) and lipid peroxidation (BODIPY™ 581/591 C11) were assessed.

RESULTS

Samples with high redox-potential (MiOXSYS® ≥1.47 sORP/106 sperm/ml) had lower sperm, motility, morphology and higher DNA fragmentation (P < 0.05). Upon further analysis, these associations were driven solely by the adjustment of sperm concentration (106 /ml) in normalised redox-potential. No significant associations between NBT-reactivity (OxiSperm® II) and measures of the sperm function or oxidative stress were observed (P > 0.05). Fluctuations in semen redox levels varied greater between men than within men over the study period.

DISCUSSION

Neither MiOXSYS® nor OxiSperm® II assays were predictive of sperm function or sperm oxidative stress. This was likely due at least in part to limited understanding of their biochemistry and clinical application. As a result, these assays seem to provide no additional clinical utility beyond that of a standard semen analysis, highlighting the imperative for the development of new robust point-of-care devices for accurately determining sperm oxidative stress.

CONCLUSION

These findings suggest that MiOXSYS® and OxiSperm® II systems for the measurement of sperm oxidative stress may have limited diagnostic potential.

Site-specific N-glycan changes during semen liquefaction

Normal liquefaction of semen is one of the key steps to ensure the smooth progress of fertilization, and glycosylation has been reported to be involved in the whole process of fertilization. Till now, it is still unclear whether and how glycosylation changes during the liquefaction process of semen. In this study, by performing a glycoproteomic analysis of human semen with the liquefaction process (liquefaction time of semen: 0 min vs 30 min) using our recently developed StrucGP software combined with the Tandem Mass Tags (TMT) based quantification, we identified 25 intact glycopeptides (IGPs) from 10 glycoproteins in semen that were significantly changed during liquefaction, including 23 up-regulated and two down-regulated. Among the 23 up-regulated glycopeptides, half were modified with sialylated glycans, suggesting that sialylated glycans may play a key role in the semen liquefaction process. The data provide an invaluable resource for further studies on the role of glycosylation during semen liquefaction.

The role of Th17 and Treg cells in normal pregnancy and unexplained recurrent spontaneous abortion (URSA): New insights into immune mechanisms

Recurrent spontaneous abortion (RSA) has various causes, including chromosomal abnormalities, a prethrombotic state, and abnormal uterine anatomical factors. However, in about 50% of cases, the cause remains unknown and is referred to as unexplained recurrent spontaneous abortion (URSA). The fetus is protected from rejection by the maternal system, acting as an allogeneic gene, and immune tolerance serves as a crucial mechanism. The Th17/Treg cell paradigm's emergence as a new subpopulation of CD4+ T cells, interacting with one another, plays an essential role in the immune microenvironment and the body's defense system. This Th17/Treg cell model helps to explain the pathology of recurrent miscarriage that could not be accounted for by the original immune mechanism based on the Th1/Th2 model. Furthermore, the plasticity of Th17 and Treg cells holds innovative significance in autoimmunity and abortion. This paper reviews the role of Th17/Treg cellular immune response in the maintaining normal pregnancy and understanding unexplained recurrent spontaneous abortion.

Immune Regulation of Seminal Plasma on the Endometrial Microenvironment: Physiological and Pathological Conditions

Seminal plasma (SP) accounts for more than 90% of semen volume. It induces inflammation, regulates immune tolerance, and facilitates embryonic development and implantation in the female reproductive tract. In the physiological state, SP promotes endometrial decidualization and causes changes in immune cells such as macrophages, natural killer cells, regulatory T cells, and dendritic cells. This leads to the secretion of cytokines and chemokines and also results in the alteration of miRNA profiles and the expression of genes related to endometrial tolerance and angiogenesis. Together, these changes modulate the endometrial immune microenvironment and contribute to implantation and pregnancy. However, in pathological situations, abnormal alterations in SP due to advanced age or poor diet in men can interfere with a woman's immune adaptation to pregnancy, negatively affecting embryo implantation and even the health of the offspring. Uterine pathologies such as endometriosis and endometritis can cause the endometrium to respond negatively to SP, which can further contribute to pathological progress and interfere with conception. The research on the mechanism of SP in the endometrium is conducive to the development of new targets for intervention to improve reproductive outcomes and may also provide new ideas for semen-assisted treatment of clinical infertility.

Low-polarity untargeted metabolomic profiling as a tool to gain insight into seminal fluid

INTRODUCTION

A decrease in sperm cell count has been observed along the last several decades, especially in the most developed regions of the world. The use of metabolomics to study the composition of the seminal fluid is a promising approach to gain access to the molecular mechanisms underlying this fact.

OBJECTIVES

In the present work, we aimed at relating metabolomic profiles of young healthy men to their semen quality parameters obtained from conventional microscopic analysis.

METHODS

An untargeted metabolomics approach focusing on low- to mid-polarity compounds was used to analyze a subset of seminal fluid samples from a cohort of over 2700 young healthy men.

RESULTS

Our results show that a broad metabolic profiling comprising several families of compounds (including acyl-carnitines, steroids, and other lipids) can contribute to effectively distinguish samples provided by individuals exhibiting low or high absolute sperm counts.

CONCLUSION

A number of metabolites involved in sexual development and function, signaling, and energy metabolism were highlighted as being distinctive of samples coming from either group, proving untargeted metabolomics as a promising tool to better understand the pathophysiological processes responsible for male fertility impairment.

Developmental origins of health and disease: Impact of paternal nutrition and lifestyle

Most epidemiological and experimental studies have focused on maternal influences on offspring's health. The impact of maternal undernutrition, overnutrition, hypoxia, and stress is linked to adverse offspring outcomes across a range of systems including cardiometabolic, respiratory, endocrine, and reproduction among others. During the past decade, it has become evident that paternal environmental factors are also linked to the development of diseases in offspring. In this article, we aim to outline the current understanding of the impact of male health and environmental exposure on offspring development, health, and disease and explore the mechanisms underlying the paternal programming of offspring health. The available evidence suggests that poor paternal pre-conceptional nutrition and lifestyle, and advanced age can increase the risk of negative outcomes in offspring, via both direct (genetic/epigenetic) and indirect (maternal uterine environment) effects. Beginning at preconception, and during utero and the early life after birth, cells acquire an epigenetic memory of the early exposure which can be influential across the entire lifespan and program a child's health. Potentially not only mothers but also fathers should be advised that maintaining a healthy diet and lifestyle is important to improve offspring health as well as the parental health status. However, the evidence is mostly based on animal studies, and well-designed human studies are urgently needed to verify findings from animal data.

Impact of sexual intercourse on frozen-thawed embryo transfer outcomes: a randomized controlled trial

BACKGROUND

Exposure of the female reproductive tract to either seminal plasma or fluid component of the ejaculate is beneficial to achieving successful embryo implantation and normal embryo development. But whether the "physical" component of sexual intercourse during the peri-transfer period have any influence on frozen-thawed embryo transfer (FET) pregnancy outcomes is not clear.

METHODS

We conducted a randomized trial that included 223 patients undergoing in vitro fertilization (IVF) treatment at a university-affiliated reproductive center from 19 July 2018 to 24 February 2019. Enrolled patients undergoing IVF treatment were randomized either to engage sexual intercourse using the barrier contraception (Group A, n = 116) or to abstain (Group B, n = 107) one night before FET. The primary outcome was clinical pregnancy rate.

RESULTS

Patients having intercourse had higher clinical pregnancy rate (51.72% vs. 37.07%, P = 0.045) and implantation rate (38.31% vs. 24.77%, P = 0.005) compared to those did not engage intercourse. However, there was no significant difference of the spontaneous abortion rate between two groups (11.67% 33 vs. 14.63%, P = 0.662).

CONCLUSIONS

Sexual intercourse before embryo transfer may improve the clinical pregnancy and implantation rates during FET cycles. However, it should be noted that patients choose only one time for sexual intercourse, that is, the night before embryo transfer.

TRIAL REGISTRATION

The present study was registered at the Chinese Clinical Trial Registry ( http://www.chictr.org.cn/ , ChiCTR1800017209).

Pre-eclampsia

Pre-eclampsia is a life-threatening disease of pregnancy unique to humans and a leading cause of maternal and neonatal morbidity and mortality. Women who survive pre-eclampsia have reduced life expectancy, with increased risks of stroke, cardiovascular disease and diabetes, while babies from a pre-eclamptic pregnancy have increased risks of preterm birth, perinatal death and neurodevelopmental disability and cardiovascular and metabolic disease later in life. Pre-eclampsia is a complex multisystem disease, diagnosed by sudden-onset hypertension (>20 weeks of gestation) and at least one other associated complication, including proteinuria, maternal organ dysfunction or uteroplacental dysfunction. Pre-eclampsia is found only when a placenta is or was recently present and is classified as preterm (delivery <37 weeks of gestation), term (delivery ≥37 weeks of gestation) and postpartum pre-eclampsia. The maternal syndrome of pre-eclampsia is driven by a dysfunctional placenta, which releases factors into maternal blood causing systemic inflammation and widespread maternal endothelial dysfunction. Available treatments target maternal hypertension and seizures, but the only 'cure' for pre-eclampsia is delivery of the dysfunctional placenta and baby, often prematurely. Despite decades of research, the aetiology of pre-eclampsia, particularly of term and postpartum pre-eclampsia, remains poorly defined. Significant advances have been made in the prediction and prevention of preterm pre-eclampsia, which is predicted in early pregnancy through combined screening and is prevented with daily low-dose aspirin, starting before 16 weeks of gestation. By contrast, the prediction of term and postpartum pre-eclampsia is limited and there are no preventive treatments. Future research must investigate the pathogenesis of pre-eclampsia, in particular of term and postpartum pre-eclampsia, and evaluate new prognostic tests and treatments in adequately powered clinical trials.

Preconception paternal mental disorders and child health: Mechanisms and interventions

Mental illness is a significant global health issue with a steady prevalence. High heritability is suspected, but genome-wide association studies only identified a small number of risk genes associated with mental disorders. This 'missing inheritance' can be partially explained by epigenetic heredity. Evidence from numerous animal models and human studies supports the possibility that preconception paternal mental health influences their offspring's mental health via nongenetic means. Here, we review two potential pathways, including sperm epigenetics and seminal plasma components. The current review highlights the role of sperm epigenetics and explores epigenetic message origination and susceptibility to chronic stress. Meanwhile, possible spatiotemporal windows and events that induce sexually dimorphic modes and effects of paternal stress transmission are inferred in this review. Additionally, we discuss emerging interventions that could potentially block the intergenerational transmission of paternal psychiatric disorders and reduce the incidence of mental illness. Understanding the underlying mechanisms by which preconception paternal stress impacts offspring health is critical for identifying strategies supporting healthy development and successfully controlling the prevalence of mental illness.

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.

On the Role of Seminal Fluid Protein and Nucleic Acid Content in Paternal Epigenetic Inheritance

The evidence supports the occurrence of environmentally-induced paternal epigenetic inheritance that shapes the offspring phenotype in the absence of direct or indirect paternal care and clearly demonstrates that sperm epigenetics is one of the major actors mediating these paternal effects. However, in most animals, while sperm makes up only a small portion of the seminal fluid, males also have a complex mixture of proteins, peptides, different types of small noncoding RNAs, and cell-free DNA fragments in their ejaculate. These seminal fluid contents (Sfcs) are in close contact with the reproductive cells, tissues, organs, and other molecules of both males and females during reproduction. Moreover, their production and use are adjusted in response to environmental conditions, making them potential markers of environmentally- and developmentally-induced paternal effects on the next generation(s). Although there is some intriguing evidence for Sfc-mediated paternal effects, the underlying molecular mechanisms remain poorly defined. In this review, the current evidence regarding the links between seminal fluid and environmental paternal effects and the potential pathways and mechanisms that seminal fluid may follow in mediating paternal epigenetic inheritance are discussed.

Seminal and vagino-uterine microbiome and their individual and interactive effects on cattle fertility

Reproductive failure is a major economical drain on cow-calf operations across the globe. It can occur in both males and females and stem from prenatal and postnatal influences. Therefore, the cattle industry has been making efforts to improve fertility and the pregnancy rate in cattle herds as an attempt to maintain sustainability and profitability of cattle production. Despite the advancements made in genetic selection, nutrition, and the implementation of various reproductive technologies, fertility rates have not significantly improved in the past 50 years. This signifies a missing factor or factors in current reproductive management practices that influence successful fertilization and pregnancy. Emerging lines of evidence derived from human and other animals including cattle suggest that the microbial continuum along the male and female reproductive tracts are associated with male and female fertility-that is, fertilization, implantation, and pregnancy success-highlighting the potential for harnessing the male and female reproductive microbiome to improve fertility in cattle. The objective of this narrative review is to provide an overview of the recent studies on the bovine seminal and vagino-uterine microbiome and discuss individual and interactive roles of these microbial communities in defining cattle fertility.

Immune–Metabolic Interactions and T Cell Tolerance in Pregnancy

Pregnancy depends on a state of maternal immune tolerance mediated by CD4+ regulatory T (Treg) cells. Uterine Treg cells release anti-inflammatory factors, inhibit effector immunity, and support adaptation of the uterine vasculature to facilitate placental development. Insufficient Treg cells or inadequate functional competence is implicated in infertility and recurrent miscarriage, as well as pregnancy complications preeclampsia, fetal growth restriction, and preterm birth, which stem from placental insufficiency. In this review we address an emerging area of interest in pregnancy immunology–the significance of metabolic status in regulating the Treg cell expansion required for maternal–fetal tolerance. We describe how hyperglycemia and insulin resistance affect T cell responses to suppress generation of Treg cells, summarize data that implicate a role for altered glucose metabolism in impaired maternal–fetal tolerance, and explore the prospect of targeting dysregulated metabolism to rebalance the adaptive immune response in women experiencing reproductive disorders.

Characteristics of menstrual cycles with or without intercourse in women with no known subfertility

STUDY QUESTION

Does sexual intercourse enhance the cycle fecundability in women without known subfertility?

SUMMARY ANSWER

Sexual intercourse (regardless of timing during the cycle) was associated with cycle characteristics suggesting higher fecundability, including longer luteal phase, less premenstrual spotting and more than 2 days of cervical fluid with estrogen-stimulated qualities.

WHAT IS KNOWN ALREADY

Human females are spontaneous ovulators, experiencing an LH surge and ovulation cyclically, independent of copulation. Natural conception requires intercourse to occur during the fertile window of a woman's menstrual cycle, i.e. the 6-day interval ending on the day of ovulation. However, most women with normal fecundity do not ovulate on Day 14, thus the timing of the hypothetical fertile window varies within and between women. This variability is influenced by age and parity and other known or unknown elements. While the impact of sexual intercourse around the time of implantation on the probability of achieving a pregnancy has been discussed by some researchers, there are limited data regarding how sexual intercourse may influence ovulation occurrence and menstrual cycle characteristics in humans.

STUDY DESIGN SIZE DURATION

This study is a pooled analysis of three cohorts of women, enrolled at Creighton Model FertilityCare centers in the USA and Canada: 'Creighton Model MultiCenter Fecundability Study' (CMFS: retrospective cohort, 1990-1996), 'Time to Pregnancy in Normal Fertility' (TTP: randomized trial, 2003-2006) and 'Creighton Model Effectiveness, Intentions, and Behaviors Assessment' (CEIBA: prospective cohort, 2009-2013). We evaluated cycle phase lengths, bleeding and cervical mucus patterns and estimated the fertile window in 2564 cycles of 530 women, followed for up to 1 year.

PARTICIPANTS/MATERIALS SETTING METHODS

Participants were US or Canadian women aged 18-40 and not pregnant, who were heterosexually active, without known subfertility and not taking exogenous hormones. Most of the women were intending to avoid pregnancy at the start of follow-up. Women recorded daily vaginal bleeding, mucus discharge and sexual intercourse using a standardized protocol and recording system for up to 1 year, yielding 2564 cycles available for analysis. The peak day of mucus discharge (generally the last day of cervical fluid with estrogen-stimulated qualities of being clear, stretchy or slippery) was used to identify the estimated day of ovulation, which we considered the last day of the follicular phase in ovulatory cycles. We used linear mixed models to assess continuous cycle parameters including cycle, menses and cycle phase lengths, and generalized linear models using Poisson regression with robust variance to assess dichotomous outcomes such as ovulatory function, short luteal phases and presence or absence of follicular or luteal bleeding. Cycles were stratified by the presence or absence of any sexual intercourse, while adjusting for women's parity, age, recent oral contraceptive use and breast feeding.

MAIN RESULTS AND THE ROLE OF CHANCE

Most women were <30 years of age (75.5%; median 27, interquartile range 24-29), non-Hispanic white (88.1%), with high socioeconomic indicators and nulliparous (70.9%). Cycles with no sexual intercourse compared to cycles with at least 1 day of sexual intercourse were shorter (29.1 days (95% CI 27.6, 30.7) versus 30.1 days (95% CI 28.7, 31.4)), had shorter luteal phases (10.8 days (95% CI 10.2, 11.5) versus 11.4 days (95% CI 10.9, 12.0)), had a higher probability of luteal phase deficiency (<10 days; adjusted probability ratio (PR) 1.31 (95% CI 1.00, 1.71)), had a higher probability of 2 days of premenstrual spotting (adjusted PR 2.15 (95% CI 1.09, 4.24)) and a higher probability of having two or fewer days of peak-type (estrogenic) cervical fluid (adjusted PR 1.49 (95% CI 1.03, 2.15)).

LIMITATIONS REASONS FOR CAUTION

Our study participants were geographically dispersed but relatively homogeneous in regard to race, ethnicity, income and educational levels, and all had male partners, which may limit the generalizability of the findings. We cannot exclude the possibility of undetected subfertility or related gynecologic disorders among some of the women, such as undetected endometriosis or polycystic ovary syndrome, which would impact the generalizability of our findings. Acute illness or stressful events might have reduced the likelihood of any intercourse during a cycle, while also altering cycle characteristics. Some cycles in the no intercourse group may have actually had undocumented intercourse or other sexual activity, but this would bias our results toward the null. The Creighton Model FertilityCare System (CrM) discourages use of barrier methods, so we believe that most instances of intercourse involved exposure to semen; however, condoms may have been used in some cycles. Our dataset lacks any information about the occurrence of female orgasm, precluding our ability to evaluate the independent or combined impact of female orgasm on cycle characteristics.

WIDER IMPLICATIONS OF THE FINDINGS

Sexual activity may change reproductive hormonal patterns, and/or levels of reproductive hormones may influence the likelihood of sexual activity. Future work may help with understanding the extent to which exposure to seminal fluid, and/or female orgasm and/or timing of intercourse could impact menstrual cycle function. In theory, large data sets from women using menstrual and fertility tracking apps could be informative if women can be appropriately incentivized to record intercourse completely. It is also of interest to understand how cycle characteristics may differ in women with gynecological problems or subfertility.

STUDY FUNDING/COMPETING INTERESTS

Funding for the research on the three cohorts analyzed in this study was provided by the Robert Wood Johnson Foundation #029258 (Creighton Model MultiCenter Fecundability Study), the Eunice Kennedy Shriver National Institute of Child Health and Human Development 1K23 HD0147901-01A1 (Time to Pregnancy in Normal Fertility) and the Office of Family Planning, Office of Population Affairs, Health and Human Services 1FPRPA006035 (Creighton Model Effectiveness, Intentions, and Behaviors Assessment). The authors declare that they have no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Extracellular vesicle-encapsulated miR-21-5p in seminal plasma prevents sperm capacitation via Vinculin inhibition

To penetrate the zona pellucida before sperm-egg binding, sperm must undergo highly time-controlled capacitation and acrosome reaction in the female reproductive tract. Our previous study demonstrated that miR-21-5p is the most abundant miRNA in boar seminal plasma (SP)-derived extracellular vesicles (EVs) and can target Vinculin (VCL) gene, which may participate in boar sperm capacitation. Thus, this study aims to explore the potential role of miR-21-5p from SP-derived EVs in preventing sperm capacitation and its underlying mechanism. We observed that sperm could incorporate miR-21-5p from SP-derived EVs. The roles of SP-derived EVs miR-21-5p in sperm capacitation were then determined using gain- and loss-of-function analyses. In addition, the expression levels of miR-21-5p, VCL, and VCL protein in liquid-preserved boar sperm following transfection were determined using RT-qPCR and Western blotting. Our results revealed that miR-21-5p overexpression inhibited sperm capacitation and acrosome reaction. Similarly, miR-21-5p expression was significantly lower (P < 0.05) in capacitated sperm than un-capacitated sperm. However, the protein level of VCL was also significantly lower (P < 0.05) in capacitated sperm than un-capacitated sperm. Furthermore, immunofluorescence analysis showed that VCL protein mainly located in sperm head and sperm capacitation was inhibited after treating with VCL protein inhibitor (Chrysin). In conclusion, our study provides reasonable evidence that miR-21-5p expression in SP-derived EVs could prevent sperm capacitation via VCL inhibition.

Investigation of Sperm and Seminal Plasma Candidate MicroRNAs of Bulls with Differing Fertility and In Silico Prediction of miRNA-mRNA Interaction Network of Reproductive Function

Simple Summary

The objective of this study was to identify differentially expressed (DE) sperm and seminal plasma microRNAs (miRNAs) in high- and low-fertile Holstein bulls (four bulls per group), integrate miRNAs to their target genes, and categorize target genes based on predicted biological processes. Out of 84 bovine-specific, prioritized miRNAs analyzed by RT-PCR, 30 were differentially expressed in high-fertile sperm and seminal plasma compared to low-fertile sperm and seminal plasma, respectively (p ≤ 0.05, fold regulation ≥5 magnitudes). Interestingly, expression levels of DE-miRNAs in sperm and seminal plasma followed a similar pattern. Highly scored integrated genes of DE-miRNAs predicted various biological and molecular functions, cellular process, and pathways. Further in silico analysis revealed categorized genes may have a plausible association with pathways regulating sperm structure and function, fertilization, and embryo and placental development. In conclusion, highly DE-miRNAs in bovine sperm and seminal plasma could be used as a tool for predicting reproductive functions. Since the identified miRNA-mRNA interactions were mostly based on predictions from public databases, the causal regulations of miRNA-mRNA and the underlying mechanisms require further functional characterization in future studies.

Abstract

Recent advances in high-throughput in silico techniques portray experimental data as exemplified biological networks and help us understand the role of individual proteins, interactions, and their biological functions. The objective of this study was to identify differentially expressed (DE) sperm and seminal plasma microRNAs (miRNAs) in high- and low-fertile Holstein bulls (four bulls per group), integrate miRNAs to their target genes, and categorize the target genes based on biological process predictions. Out of 84 bovine-specific, prioritized miRNAs analyzed by RT-PCR, 30 were differentially expressed in high-fertile sperm and seminal plasma compared to low-fertile sperm and seminal plasma, respectively (p ≤ 0.05, fold regulation ≥ 5 magnitudes). The expression levels of DE-miRNAs in sperm and seminal plasma followed a similar pattern. Highly scored integrated genes of DE-miRNAs predicted various biological and molecular functions, cellular process, and pathways. Further, analysis of the categorized genes showed association with pathways regulating sperm structure and function, fertilization, and embryo and placental development. In conclusion, highly DE-miRNAs in bovine sperm and seminal plasma could be used as a tool for predicting reproductive functions. Since the identified miRNA-mRNA interactions were mostly based on predictions from public databases, the causal regulations of miRNA-mRNA and the underlying mechanisms require further functional characterization in future studies.

First-Trimester Serum Cytokine Profile in Pregnancies Conceived After Assisted Reproductive Technology (ART) With Subsequent Pregnancy-Induced Hypertension

Pregnancy-induced hypertension (PIH) is one of the most common pregnancy complications that seriously affects the mother and fetus. The incidence of PIH is higher in pregnancies conceived after assisted reproductive technology (ART) than in spontaneous pregnancies; thus, exploring potential serum biomarkers before PIH onset is of great significance for effective early prediction and prevention of PIH in the ART population. Cytokines are involved in the inflammatory response and immune regulation, which play an essential role in the pathogenesis of PIH. A description of the cytokine profile in the first trimester of pregnancy could help identify new diagnostic tools and develop targeted therapies for PIH in the ART population. The concentrations of classical predictive markers for PIH and another 48 cytokines were measured in the first-trimester pregnancy serum samples from 33 PIH patients and 33 matched normotensive controls (NC), both of whom conceived after ART treatment. The measured values were compared and analyzed between NC and PIH, followed by comprehensive bioinformatic analysis and logistic regression analysis. There was no significant difference in classical predictive markers, including Activin A, PlGF, sFLT1 (VEGFR), and sFLT1/PlGF, between the PIH and NC groups (P > 0.05), while 29 cytokines were significantly lower in the PIH group than in the NC group (P < 0.05). Logistic regression analysis revealed that 17 cytokines (IL-2Rα, M-CSF, IL-6, IL-2, β-NGF, IL-7, IL-12 (p70), SCF, IL-10, IL-9, MIG, GM-CSF, LIF, IL-1α, MCP-3, IL-4, and HGF) in the first-trimester pregnancy serum were significantly negatively correlated with the subsequent onset of PIH. With the top 3 cytokines (IL-7, MIG, and SCF) of receiver operating characteristic (ROC) analysis, we constructed an efficient multifactor combined detection and prediction model for PIH in ART pregnancy. Classical early predictors for hypertensive disorder complicating pregnancy cannot distinguish PIH from their normal peers in ART pregnancy. In comparison, the description of the cytokine profile in the first trimester of pregnancy enables us to distinguish high-risk ART pregnancy for PIH, permitting enough time for PIH prevention therapy. The cytokine profile we described also provides immunological insight into the further mechanistic exploration of PIH.

Extracellular vesicles from seminal plasma improved development of in vitro-fertilized mouse embryos

In vitro fertilization (IVF) has wide application in human infertility and animal breeding. It is also used for research on reproduction, fertility and development. However, IVF embryos are still inferior to their in vivo counterparts. Some substances in seminal plasma appear to have important roles in embryo development, and during the traditional IVF procedure, the seminal plasma is washed away. In this study, extracellular vesicles (EVs) were concentrated from seminal plasma by ultracentrifugation, visualized using transmission electron microscopy, and particle size distributions and concentrations were determined with a NanoSight particle analyzer. We found particles of various sizes in the seminal plasma, the majority having diameters ranging from 100 to 200 nm and concentrations of 6.07 × 10¹⁰ ± 2.91 × 10⁹ particles/ml. Addition of seminal plasma EVs (SP-EVs) to the IVF medium with mouse oocytes and sperm significantly increased the rate of blastocyst formation and the inner cell mass (ICM)/trophectoderm (TE) cell ratio, and reduced the apoptosis of blastocysts. Our findings provide new insights into the role of seminal plasma EVs in mediating embryo development and it suggests that SP-EVs may be used to improve the developmental competence of IVF embryos, which has important significance for assisted reproduction in animals and humans.

Fetal‐placental antigens and the maternal immune system: Reproductive immunology comes of age

Reproductive physiology and immunology as scientific disciplines each have rich, largely independent histories. The physicians and philosophers of ancient Greece made remarkable observations and inferences to explain regeneration as well as illness and immunity. The scientific enlightenment of the renaissance and the technological advances of the past century have led to the explosion of knowledge that we are experiencing today. Breakthroughs in transplantation, immunology, and reproduction eventually culminated with Medawar’s discovery of acquired immunological tolerance, which helped to explain the transplantation success and failure. Medawar’s musings also keenly pointed out that the fetus apparently breaks these newly discovered rules, and with this, the field of reproductive immunology was launched. As a result of having stemmed from transplantation immunology, scientist still analogizes the fetus to a successful allograft. Although we now know of the fundamental differences between the two, this analogy remains a useful tool to understand how the fetus thrives despite its immunological disparity with the mother. Here, we review the history of reproductive immunology, and how major and minor histocompatibility antigens, blood group antigens, and tissue‐specific “self” antigens from the fetus and transplanted organs parallel and differ.

Precision Structural Interpretation of Site-Specific N-Glycans in Seminal Plasma

N-Linked glycoproteins are rich in seminal plasma, playing various essential roles in supporting sperm function and the fertilization process. However, the detailed information on these glycoproteins, particularly site-specific glycan structures, is still limited. In this study, a precision site-specific N-glycoproteome map of human seminal plasma was established by employing the site-specific glycoproteomic approach and a recently developed glycan structure interpretation software, StrucGP. A total of 9567 unique glycopeptides identified in human seminal plasma were composed of 773 N-linked glycan structures and 1019 N-glycosites from 620 glycoproteins. These glycans were comprised of four types of core structures and 13 branch structures. The majority of identified glycoproteins functioned in response to stimulus and immunity. As we reported in human spermatozoa, heavy fucosylation (fucose residues ≥6 per glycan) was also detected on seminal plasma glycoproteins such as clusterin and galectin-3-binding protein, which were involved in the immune response of biological processes and reactome pathways. Comparison of site-specific glycans between seminal plasma and spermatozoa revealed more complicated glycan structures in seminal plasma than in spermatozoa, even on their shared glycoproteins. These present data will be greatly beneficial for the in-depth structural and functional study of glycosylation in the male reproduction system.

Pre-eclampsia: a Scoping Review of Risk Factors and Suggestions for Future Research Direction

Abstract

Most of maternal deaths are preventable, and one-quarter of maternal deaths are due to pre-eclampsia and eclampsia. Prenatal screening is essential for detecting and managing pre-eclampsia. However, pre-eclampsia screening is solely based on maternal risk factors and has low (< 5% in the USA) detection rates. This review looks at pre-eclampsia from engineering, public health, and medical points of view. First, pre-eclampsia is defined clinically, and the biological basis of established risk factors is described. The multiple theories behind pre-eclampsia etiology should serve as the scientific basis behind established risk factors for pre-eclampsia; however, African American race does not have sufficient evidence as a risk factor. We then briefly describe predictive statistical models that have been created to improve screening detection rates, which use a combination of biophysical and biochemical biomarkers, as well as aspects of patient medical history as inputs. Lastly, technologies that aid in advancing pre-eclampsia screening worldwide are explored. The review concludes with suggestions for more robust pre-eclampsia research, which includes diversifying study sites, improving biomarker analytical tools, and for researchers to consider studying patients before they become pregnant to improve pre-eclampsia detection rates. Additionally, researchers must acknowledge the systemic racism involved in using race as a risk factor and include qualitative measures in study designs to capture the effects of racism on patients.

Lay Summary

Pre-eclampsia is a pregnancy-specific hypertensive disorder that can affect almost every organ system and complicates 2-8% of pregnancies globally. Here, we focus on the biological basis of the risk factors that have been identified for the condition. African American race currently does not have sufficient evidence as a risk factor and has been poorly studied. Current clinical methods poorly predict a patient's likelihood of developing pre-eclampsia; thus, researchers have made statistical models that are briefly described in this review. Then, low-cost technologies that aid in advancing pre-eclampsia screening are discussed. The review ends with suggestions for research direction to improve pre-eclampsia screening in all settings.Overall, we suggest that the future of pre-eclampsia screening should aim to identify those at risk before they become pregnant. We also suggest that the clinical standard of assessing patient risk solely on patient characteristics needs to be reevaluated, that study locations of pre-eclampsia research need to be expanded beyond a few high-income countries, and that low-cost technologies should be developed to increase access to prenatal screening.

Shuttle Transfer of mRNA Transcripts via Extracellular Vesicles From Male Reproductive Tract Cells to the Cumulus–Oocyte Complex in Rabbits (Oryctolagus cuniculus)

Semen is known to contain an ovulation-inducing factor (identified as a nerve growth factor, NGF) that shows a significant increase in ovulation after semen deposition in induced ovulatory species. However, the interplay between the male reproductive tract cells and oocyte maturation through messenger RNA (mRNA) cargo is yet to be investigated. Extracellular vesicles (EVs) from the primary culture of rabbit prostate (pEVs), epididymis (eEVs), and testis (tEVs) were isolated to examine their contents for several mRNA transcripts through relative quantitative PCR (RT-qPCR). The expressions of NGF, neurotrophin (NTF3), vascular endothelial growth factor A (VEGFA), A disintegrin and metalloprotease 17 (ADAM17), midkine (MDK), kisspeptin (KISS1), and gonadotrophin-releasing hormone (GNRH1) were examined in isolated EVs. EVs were characterized through transmission electron microscopy. EV uptake by cumulus cell culture was confirmed through microscopic detection of PKH26-stained EVs. Furthermore, the effects of pEVs, eEVs, and tEVs were compared with NGF (10, 20, and 30 ng/ml) supplementation on oocyte in vitro maturation (IVM) and transcript expression. KISS1, NTF3, MDK, ADAM17, GAPDH, and ACTB were detected in all EV types. GNRH1 was detected in tEVs. NGF was detected in pEVs, whereas VEGFA was detected in eEVs. pEVs, eEVs, and 20 ng/ml NGF showed the highest grade of cumulus expansion, followed by tEVs and 10 ng/ml NGF. Control groups and 30 ng/ml NGF showed the least grade of cumulus expansion. Similarly, first polar body (PB) extrusion was significantly increased in oocytes matured with eEVs, pEVs, tEVs, NGF20 (20 ng/ml NGF), NGF10 (10 ng/ml NGF), control, and NGF30 (30 ng/ml NGF). Additionally, the expression of NGFR showed a 1.5-fold increase in cumulus cells supplemented with eEVs compared with the control group, while the expression of PTGS2 (COX2) and NTRK showed 3-fold and 5-fold increase in NGF20-supplemented cumulus-oocyte complexes (COCs), respectively. Oocyte PMP15 expression showed a 1.8-fold increase in IVM medium supplemented with eEVs. Additionally, oocyte NGFR and NTRK expressions were drastically increased in IVM medium supplemented with pEVS (3.2- and 1.6-fold, respectively) and tEVs (4- and 1.7-fold, respectively). This is the first report to examine the presence of mRNA cargo in the EVs of male rabbit reproductive tract cells that provides a model for the stimulation of female rabbits after semen deposition.

The Association of HLA-G Gene Polymorphism and Its Soluble Form With Male Infertility

Successful reproduction depends on many factors. Male factors contribute to infertility in approximately 50% of couples who fail to conceive. Seminal plasma consists of secretions from different accessory glands containing a mixture of various cytokines, chemokines, and growth factors, which together can induce a local immune response that might impact on a male’s as well as a female’s fertility. Human leukocyte antigen (HLA)-G expression has been suggested as an immunomodulatory molecule that influences pregnancy outcome. The HLA-G gene encodes either membrane-bound or/and soluble proteins. The aim of this study was the evaluation of HLA-G polymorphisms and their impact on soluble HLA-G (sHLA-G) production. We tested the HLA-G polymorphism in three positions: rs1632947: c.-964G>A; rs1233334: c.-725G>C/T in the promoter region; rs371194629: c.∗65_∗66insATTTGTTCATGCCT in the 3′ untranslated region. We tested two cohorts of men: 663 who participated in in vitro fertilization (test material was blood or sperm), and 320 fertile controls who possessed children born after natural conception (test material was blood). Since 50% of men visiting assisted reproductive clinics have abnormal semen parameters, we wondered if men with normal sperm parameters differ from those with abnormal parameters in terms of HLA-G polymorphism and secretion of sHLA-G into semen. We found that certain rs1632947-rs1233334-rs371194629 HLA-G haplotypes and diplotypes were associated with male infertility, while others were protective. Normozoospermic men with the A-C-del haplotype and A-C-del/A-C-del diplotype secreted the most sHLA-G into semen (574.1 IU/mL and 1047.0 IU/mL, respectively), while those with the G-C-ins haplotype and G-C-ins/G-C-ins diplotype – the least (80.8 IU/mL and 75.7 IU/mL, respectively). Men with the remaining haplotypes/diplotypes secreted sHLA-G at an intermediate level. However, only in one haplotype, namely G-C-ins, did we observe strong significant differences in the concentration of sHLA-G in the semen of men with teratozoospermia compared to men with normal sperm parameters (p = 0.009). In conclusion, fertile men differ in the profile of HLA-G polymorphism from men participating in IVF. Among all HLA-G haplotypes, the most unfavorable for male fertility is the G-C-ins haplotype, which determines the secretion of the lowest concentration of the soluble HLA-G molecule. This haplotype may reduce sperm parameters.

Paternal nutritional programming of lipid metabolism is propagated through sperm and seminal plasma

BACKGROUND

The paternal diet affects lipid metabolism in offspring for at least two generations through nutritional programming. However, we do not know how this is propagated to the offspring.

OBJECTIVES

We tested the hypothesis that the changes in lipid metabolism that are driven by paternal diet are propagated through spermatozoa and not seminal plasma.

METHODS

We applied an updated, purpose-built computational network analysis tool to characterise control of lipid metabolism systemically (Lipid Traffic Analysis v2.3) on a known mouse model of paternal nutritional programming.

RESULTS

The analysis showed that the two possible routes for programming effects, the sperm (genes) and seminal plasma (influence on the uterine environment), both have a distinct effect on the offspring's lipid metabolism. Further, the programming effects in offspring suggest that changes in lipid distribution are more important than alterations in lipid biosynthesis.

CONCLUSIONS

These results show how the uterine environment and genes both affect lipid metabolism in offspring, enhancing our understanding of the link between parental diet and metabolism in offspring.

Measuring Reactive Oxygen Species in Semen for Male Preconception Care: A Scientist Perspective

Oxidative stress and elevated levels of seminal and sperm reactive oxygen species (ROS) may contribute to up to 80% of male infertility diagnosis, with sperm ROS concentrations at fertilization important in the development of a healthy fetus and child. The evaluation of ROS in semen seems promising as a potential diagnostic tool for male infertility and male preconception care with a number of clinically available tests on the market (MiOXSYS, luminol chemiluminescence and OxiSperm). While some of these tests show promise for clinical use, discrepancies in documented decision limits and lack of cohort studies/clinical trials assessing their benefits on fertilization rates, embryo development, pregnancy and live birth rates limit their current clinical utility. In this review, we provide an update on the current techniques used for analyzing semen ROS concentrations clinically, the potential to use of ROS research tools for improving clinical ROS detection in sperm and describe why we believe we are likely still a long way away before semen ROS concentrations might become a mainstream preconception diagnostic test in men.

A Preconception Paternal Fish Oil Diet Prevents Toxicant-Driven New Bronchopulmonary Dysplasia in Neonatal Mice

New bronchopulmonary dysplasia is a developmental lung disease associated with placental dysfunction and impaired alveolarization. Risk factors for new BPD include prematurity, delayed postnatal growth, the dysregulation of epithelial-to-mesenchymal transition (EMT), and parental exposure to toxicants. Our group previously reported that a history of paternal toxicant exposure increased the risk of prematurity and low birth weight in offspring. A history of paternal toxicant exposure also increased the offspring's risk of new BPD and disease severity was increased in offspring who additionally received a supplemental formula diet, which has also been linked to poor lung development. Risk factors associated with new BPD are well-defined, but it is unclear whether the disease can be prevented. Herein, we assessed whether a paternal fish oil diet could attenuate the development of new BPD in the offspring of toxicant exposed mice, with and without neonatal formula feeding. We investigated the impact of a paternal fish oil diet preconception because we previously reported that this intervention reduces the risk of TCDD associated placental dysfunction, prematurity, and low birth weight. We found that a paternal fish oil diet significantly reduced the risk of new BPD in neonatal mice with a history of paternal toxicant exposure regardless of neonatal diet. Furthermore, our evidence suggests that the protective effects of a paternal fish oil diet are mediated in part by the modulation of small molecules involved in EMT.

MicroRNA-222 Transferred From Semen Extracellular Vesicles Inhibits Sperm Apoptosis by Targeting BCL2L11

Seminal plasma contains a large number of extracellular vesicles (EVs). However, the roles of these EVs and their interactions with sperm are not clear. To identify the important molecules affecting sperm motility in EVs, we analyzed RNA from seminal plasma EVs of boars with different sperm motility using whole-transcriptome sequencing and proteomic analysis. In total, 7 miRNAs, 67 lncRNAs, 126 mRNAs and 76 proteins were differentially expressed between the two groups. We observed that EV-miR-222 can obviously improve sperm motility. In addition, the results suggested that miR-222 was transferred into sperm by the EVs and that miR-222 affected sperm apoptosis by inhibiting the expression of EGFR, BCL2L11, BAX, CYCs, CASP9 and CASP3. The results of electron microscopy also showed that overexpression of miR-222 in EVs could reduce sperm apoptosis. The study of the whole transcriptomes and proteomes of EVs in boar semen revealed some miRNAs may play an important role in these EVs interactions with Duroc sperm, and the findings suggest that the release of miR-222 by semen EVs is an important mechanism by which sperm viability is maintained and sperm apoptosis is reduced. Our studies provide a new insight of miR-222 in EVs regulation for sperm motility and sperm apoptosis.

Seminal Plasma and Seminal Plasma Exosomes of Aged Male Mice Affect Early Embryo Implantation via Immunomodulation

Seminal plasma (SP), particularly SP exosomes (sExos), alters with age and can affect female mouse uterine immune microenvironment. However, the relationship between fertility decline in reproductively older males, and SP and sExos age-related changes, which may compromise the uterine immune microenvironment, remains unclear. The present study demonstrated that the implantation rate of female mice treated with SP from reproductively older male mice (aged-SP group) was lower than that of those treated with SP from younger male mice (young-SP group). RNA-sequencing analysis revealed altered levels of dendritic cell (DC)-related cytokines and chemokines in the uteri of the former group compared with those of the latter group. In vivo and in vitro experiments demonstrated a weaker inhibitory effect of aged SP on DC maturation than of young SP upon stimulation. After isolating and characterizing sExos from young and advanced-age male mice, we discovered that insemination of a subset of the aged-SP group with sExos from young male mice partially recovered the implantation rate decline. Additional in vivo and in vitro experiments revealed that sExos extracted from age male mice exerted a similar effect on DC maturation as SP of aged mice, indicating an age-related sExos inhibitory effect. In conclusion, our study demonstrated that age-related alterations of sExos may be partially responsible for lower implantation rates in the aged-SP group compared with those in the young-SP group, which were mediated by uterine immunomodulation. These findings provide new insights for clinical seminal adjuvant therapy.

The Health Benefits of Sexual Expression

Objective

Sexual activity is a fundamental human function with short-term and long-term emotional, social, and physical benefits. Yet within healthcare, sexuality has been marginalized and many HCPs are unaware of its beneficial implications for immediate and long-term health.

Methods

To challenge this assumption we combined the data that already had been collected by the authors with an extensive search of articles on the various health benefits of sexual activity. The results of this process are displayed according to short-term, intermediate-term, and long-term benefits with some explanation about potential causal relationships.

Results

For the time being, it cannot yet be proved that "good sex promotes good health" since good health also favors good sex.

Conclusions

Despite lacking such convincing evidence, the article concludes with recommendations for the relevant professions. The balance of research supports that sexuality anyhow deserves greater attention among HCPs and that sexuality research needs better integration within health research.

Characterization of local and peripheral immune system in pregnant and nonpregnant ewes

Modulation of the immune system is known to be important for successful pregnancy but how immune function might differ between the lymph nodes draining the reproductive tract and peripheral lymph nodes is not well understood. Additionally, if immune system changes in response to the presence of an embryo during early pregnancy, and if this response differs in local versus peripheral immune tissue, has not been well characterized. To address these questions, we examined expression of genes important for immune function using NanoString technology in the ampulla and isthmus of the oviduct, endometrium, lymph nodes draining the reproductive tract (lumbo-aortic and medial iliac) as well as a peripheral lymph node (axillary), the spleen, and circulating immune cells from ewes on day 5 of the estrous cycle or pregnancy. Concentrations of estradiol and progesterone in plasma were also determined. Principal component analysis revealed separation of the local from the peripheral lymph nodes (MANOVA P = 3.245e-08, R2 = 0.3) as well as separation of tissues from pregnant and nonpregnant animals [lymph nodes (MANOVA P = 2.337e-09, R2 = 0.5), reproductive tissues (MANOVA P = 2.417e-14, R2 = 0.47)]. Nine genes were differentially (FDR < 0.10) expressed between lymph node types, with clear difference in expression of these genes between the lumbo-aortic and axillary lymph nodes. Expression of these genes in the medial iliac lymph node was not consistently different to either the axillary or the lumbo-aortic lymph node. Expression of IL10RB was increased (FDR < 0.05) by 24% in the reproductive tissue of the pregnant animals compared to nonpregnant animals. Analysis of gene categories revealed that expression of genes of the T-cell receptor pathway in reproductive tract tissues was associated (P < 0.05) with pregnancy status. In conclusion, assessment of gene expression of reproductive and immune tissue provides evidence for a specialization of the local immune system around the reproductive tract potentially important for successful establishment of pregnancy. Additionally, differences in gene expression patterns in reproductive tissue from pregnant and nonpregnant animals could be discerned as early as day 5 of pregnancy. This was found to be associated with expression of genes important for T-cell function and thus highlights the important role of these cells in early pregnancy.

A new model for evaluating the influence of social networks, social learning, and supportive policies on the desire of women for fertility

BACKGROUND: Nowadays, social networks become so famous and attract a lot of users. In recent eras, the increase of online social networks and the digitization of communication types have meant that online social networks have become a significant part of social network examination. OBJECTIVE: In this paper, we investigate the social networks to study the desire of women for fertility. The study has delivered new visions into the elements of reproductive behavior and has discussed the development of increasingly refined and realistic theories of fertility desire. METHODS: A questionnaire is intended for evaluating the elements of the model. Questionnaires were reviewed by experts with significant experiences in this domain. From 384 users of Telegram as an important social network in Iran, data are collected. For statistical examination, the SPSS 22 and SMART- PLS 3.2 software are also utilized. RESULTS: Results confirmed the validity of the model for assessing of the desire of women for fertility. The outcomes have indicated that the social network has a negative effect on the desire of women for fertility. Besides, the results have shown that the role of social networks on social learning is significant and positive. Furthermore, the role of social learning and supportive policies on the desire of women for fertility is positive and significant. CONCLUSIONS: According to findings, managers have enough precision in training women and daughters through social networks and social learning to enhance the desire for fertility. Finally, it is significant to note that since data are self-reported, they could be affected by rationalization and may not correlate with fertility behavior. In future studies, by gathering a comprehensive sample, other important elements can be considered that cause the desire of women for fertility.

Seminal exosomes - An important biological marker for various disorders and syndrome in human reproduction

BACKGROUND

Exosomes are nano-sized membrane vesicles, secreted by different types of cells into the body's biological fluids. They are found in abundance in semen as compared to other fluids. Exosomes contain a cargo of lipid molecules, proteins, phospholipids, cholesterol, mRNAs, and miRNAs. Each molecule of seminal exosomes (SE) has a potential role in male reproduction for childbirth. Many potential candidates are available within the seminal exosomes that can be used as diagnostic markers for various diseases or syndromes associated with male reproduction. Also these seminal exospmes play a major role in female reproductive tract for effective fertilization.

AIM

The aim of this review is to focus on the advancement of human seminal exosomal research and its various properties.

METHODS

We used many databases like Scopus, Google scholar, NCBI-NLM and other sources to filter the articles of interest published in exosomes. We used phrases like "Exosomes in human semen", "Composition of exosomes in human semen" and other relevant words to filter the best articles.

RESULTS

Seminal exosomes play a major role in sperm functions like cell-to-cell communication, motility of the sperm cells, maintaining survival capacity for the sperm in the female reproductive tract and spermatogenesis. Also, seminal exosomes are used as a carrier for many regulatory elements using small RNA molecules. miRNAs of the seminal exosomes can be used as a diagnostic marker for prostate cancer instead of prostate specific antigen (PSA). Epididymosomes can be used as a biomarker for reproductive diseases and male infertility.

CONCLUSION

Seminal exosomes could be used as biological markers for various reproductive disorders, male infertility diagnosis, and it can be used in anti-retroviral research for the identification of novel therapeutics for HIV-1 infection and transmission.

Immunological response of fallopian tube epithelial cells to spermatozoa through modulating cytokines and chemokines

BACKGROUND

Spermatozoa interactions with fallopian tubes may influence fertilization. The purpose was to investigate cytokines, chemokines and growth factors expression from human fallopian tube epithelial cells (OE-E6/E7) exposed to spermatozoa.

METHODS

Fresh semen samples were obtained from 10 healthy normozoospermic men. Sperms were prepared and co-cultured with OE-E6/E7. The cell line without spermatozoa was considered as the control group. Afterwards, Expression of 84 cytokines from OE-E6/E7 cell line in the presence and absence of spermatozoa were measured using PCR-array. Quantitative PCR was performed on seven genes to confirm the results of PCR-array analysis. Differentially expressed genes were subjected to www.geneontology.org and www.pantherdb.org to perform GO enrichment and panther pathway analysis. The concentration of IL-8, IL-10, IL-1B and BMP-4 in culture medium were analyzed by ELISA.

RESULTS

Sperm interaction with the epithelial cells resulted in a significant increase in expression of TGF-β2, BMP-4, IL-10, IL-9, and CD40LG markers. Moreover, expression of IL-16, IL-17F, SPP-1, CXCL-13, MSTN, IL-1A, IL-1B, IL-8, BMP-7, CSF-2, CSF-3, VEGF-A, OSM, LTA, TNF, TNFRSF11B, TNFSF11, CCL-11, CCL-20, CCL-24, CCL-3, CCL-8, CX3CL1 and CXCL-9 were considerably reduced in presence of spermatozoa. Panther pathway analysis discovered 3 pathways for upregulated genes including gonadotropin-releasing hormone receptor, TGF-beta and interleukin signaling pathways. Furthermore, 9 pathways were detected for down-regulated genes. Inflammation signaling pathway which is mediated by chemokine and cytokine contains the most number of genes.

CONCLUSION

This study indicates that sperm modifies expression of cytokines, chemokines and growth factors from OE-E6/E7. Moreover, altered genes expression are toward higher survival chance of the spermatozoa.

CD8+ T Cell Functional Exhaustion Overrides Pregnancy-Induced Fetal Antigen Alloimmunization

Pregnancy necessitates physiological exposure, and often re-exposure, to foreign fetal alloantigens. The consequences after pregnancy are highly varied, with evidence of both alloimmunization and expanded tolerance phenotypes. We show that pregnancy primes the accumulation of fetal-specific maternal CD8⁺ T cells and their persistence as an activated memory pool after parturition. Cytolysis and the potential for robust secondary expansion occurs with antigen re-encounter in non-reproductive contexts. Comparatively, CDS⁺ T cell functional exhaustion associated with increased PD-1 and LAG-3 expression occurs with fetal antigen re-stimulation during subsequent pregnancy. PD-L1/LAG-3 neutralization unleashes the activation of fetal-specific CD8⁺ T cells, causing fetal wastage selectively during secondary but not primary pregnancy. Thus, CD8⁺ T cells with fetal alloantigen specificity persist in mothers after pregnancy, and protection against fetal wastage in subsequent pregnancies is maintained by their unique susceptibility to functional exhaustion. Together, distinct mechanisms whereby fetal tolerance is maintained during primary compared with subsequent pregnancies are demonstrated.

Expecting mothers are immunologically aware of, but do not reject, genetically foreign tissues of the developing fetus. Comparing tolerance occuring during first and subsequent pregnancies, Kinder et al. show that activated memory CD8⁺ T cells primed by prior pregnancy are uniquely prone to functional exhaustion with fetal antigen re-stimulation.

Vaginal neutrophils eliminate sperm by trogocytosis

STUDY QUESTION

What is the vaginal polymorphonuclear (PMN) spermicidal mechanism to reduce the excess of sperm?

SUMMARY ANSWER

We show that PMNs are very efficient at killing sperm by a trogocytosis-dependent spermicidal activity independent of neutrophil extracellular traps (NETs).

WHAT IS KNOWN ALREADY

Trogocytosis has been described as an active membrane exchange between immune cells with a regulatory purpose. Recently, trogocytosis has been reported as a mechanism which PMNs use to kill tumour cells or Trichomonas vaginalis.

STUDY DESIGN, SIZE, DURATION

We used in vivo murine models and human ex vivo sperm and PMNs to investigate the early PMN-sperm response.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We set up a live/dead sperm detection system in the presence of PMNs to investigate in vivo and ex vivo PMN-spermicidal activity by confocal microscopy, flow cytometry and computer-assisted sperm analysis (SCA).

MAIN RESULTS AND THE ROLE OF CHANCE

We revealed that PMNs are highly efficient at killing sperm by way of a NETs-independent, contact-dependent and serine proteases-dependent engulfment mechanism. PMNs 'bite' sperm and quickly reduce sperm motility (within 5 min) and viability (within 20 min) after contact.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

This study was conducted using murine models and healthy human blood PMNs; whether it is relevant to human vaginal PMNs or to cases of infertility is unknown.

WIDER IMPLICATIONS OF THE FINDINGS

Vaginal PMNs attack and immobilize excess sperm in the vagina by trogocytosis because sperm are exogenous and may carry pathogens. Furthermore, this mechanism of sperm regulation has low mucosal impact and avoids an exacerbated inflammatory response that could lead to mucosal damage or infertility.

STUDY FUNDING/COMPETING INTEREST(S)

This work was partially supported by Ministry of Economy and Competitiveness ISCIII-FIS grants, PI16/00050, and PI19/00078, co-financed by ERDF (FEDER) Funds from the European Commission, 'A way of making Europe' and IiSGM intramural grant II-PI-MRC-2017. M.R. holds a Miguel Servet II contract (CPII14/00009). M.C.L. holds IiSGM intramural contract. There are no competing interests.

Seminal plasma promotes decidualization of endometrial stromal fibroblasts in vitro from women with and without inflammatory disorders in a manner dependent on interleukin-11 signaling

STUDY QUESTION

Do seminal plasma (SP) and its constituents affect the decidualization capacity and transcriptome of human primary endometrial stromal fibroblasts (eSFs)?

SUMMARY ANSWER

SP promotes decidualization of eSFs from women with and without inflammatory disorders (polycystic ovary syndrome (PCOS), endometriosis) in a manner that is not mediated through semen amyloids and that is associated with a potent transcriptional response, including the induction of interleukin (IL)-11, a cytokine important for SP-induced decidualization.

WHAT IS KNOWN ALREADY

Clinical studies have suggested that SP can promote implantation, and studies in vitro have demonstrated that SP can promote decidualization, a steroid hormone-driven program of eSF differentiation that is essential for embryo implantation and that is compromised in women with the inflammatory disorders PCOS and endometriosis.

STUDY DESIGN, SIZE, DURATION

This is a cross-sectional study involving samples treated with vehicle alone versus treatment with SP or SP constituents. SP was tested for the ability to promote decidualization in vitro in eSFs from women with or without PCOS or endometriosis (n = 9). The role of semen amyloids and fractionated SP in mediating this effect and in eliciting transcriptional changes in eSFs was then studied. Finally, the role of IL-11, a cytokine with a key role in implantation and decidualization, was assessed as a mediator of the SP-facilitated decidualization.

PARTICIPANTS/MATERIALS, SETTING, METHODS

eSFs and endometrial epithelial cells (eECs) were isolated from endometrial biopsies from women of reproductive age undergoing benign gynecologic procedures and maintained in vitro. Assays were conducted to assess whether the treatment of eSFs with SP or SP constituents affects the rate and extent of decidualization in women with and without inflammatory disorders. To characterize the response of the endometrium to SP and SP constituents, RNA was isolated from treated eSFs or eECs and analyzed by RNA sequencing (RNAseq). Secreted factors in conditioned media from treated cells were analyzed by Luminex and ELISA. The role of IL-11 in SP-induced decidualization was assessed through Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas-9-mediated knockout experiments in primary eSFs.

MAIN RESULTS AND THE ROLE OF CHANCE

SP promoted decidualization both in the absence and presence of steroid hormones (P < 0.05 versus vehicle) in a manner that required seminal proteins. Semen amyloids did not promote decidualization and induced weak transcriptomic and secretomic responses in eSFs. In contrast, fractionated SP enriched for seminal microvesicles (MVs) promoted decidualization. IL-11 was one of the most potently SP-induced genes in eSFs and was important for SP-facilitated decidualization.

LARGE SCALE DATA

RNAseq data were deposited in the Gene Expression Omnibus repository under series accession number GSE135640.

LIMITATIONS, REASONS FOR CAUTION

This study is limited to in vitro analyses.

WIDER IMPLICATIONS OF THE FINDINGS

Our results support the notion that SP promotes decidualization, including within eSFs from women with inflammatory disorders. Despite the general ability of amyloids to induce cytokines known to be important for implantation, semen amyloids poorly signaled to eSFs and did not promote their decidualization. In contrast, fractionated SP enriched for MVs promoted decidualization and induced a transcriptional response in eSFs that overlapped with that of SP. Our results suggest that SP constituents, possibly those associated with MVs, can promote decidualization of eSFs in an IL-11-dependent manner in preparation for implantation.

STUDY FUNDING/COMPETING INTEREST(S)

This project was supported by NIH (R21AI116252, R21AI122821 and R01AI127219) to N.R.R. and (P50HD055764) to L.C.G. The authors declare no conflict of interest.

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.

Effects of Pulsed-Wave Photobiomodulation Therapy on Human Spermatozoa

BACKGROUND AND OBJECTIVES

Previous studies reported that photobiomodulation (PBM) positively affects the mitochondrial respiratory chain in sperm, resulting in improved motility and velocity. As laser settings are not yet fully established, the present study aimed at optimizing PBM on human sperm. In addition, possible side-effects of PBM on sperm DNA fragmentation level and acrosomal integrity have been analyzed.

STUDY DESIGN/MATERIALS AND METHODS

A pulsed laser-probe (wavelength 655 nm, output power 25 mW/cm², impulse duration 200 nanoseconds) was used. Native fresh liquefied semen samples underwent radiation with energy doses of 0 (control), 4, 6, and 10 J/cm². Sperm parameters were assessed at 0, 30, 60, 90, and 120 minutes after radiation using a computer-assisted sperm analysis system. Motility and velocity of sperm from asthenozoospermic patients (n = 42) and normozoospermic controls (n = 22) were measured. The amount of DNA strand breaks was analyzed using ligation-mediated quantitative polymerase chain reaction in patients with asthenozoospermia (n = 18) and normozoospermia (n = 13). Post-irradiance acrosomal integrity was investigated using flow cytometry based on CD46 protein expression (n = 7).

RESULTS

Exposure to laser energy-doses of 4 and 6 J/cm² improved sperm motility and velocity in asthenozoospermic patients. PBM exhibited no significant effect on DNA fragmentation level and expression of CD46 serving as a biomarker for acrosome integrity.

CONCLUSION

PBM improves sperm motility parameters by maintaining DNA and acrosome integrity and, therefore, represents a promising new tool for assisted reproductive therapy. In particular, improving sperm motility in asthenozoospermic patients by PBM in future may contribute to increasing the chance for successful intrauterine insemination. The present trial has no clinical registration number, as only in vitro studies were performed. The study was approved by the local ethics committee and performed according to the Declaration of Helsinki. Lasers Surg. Med. © 2021 The Authors. Lasers in Surgery and Medicine published by Wiley Periodicals LLC.

Role of Zinc (Zn) in Human Reproduction: A Journey from Initial Spermatogenesis to Childbirth

Zinc (Zn), the second-most necessary trace element, is abundant in the human body. The human body lacks the capacity to store Zn; hence, the dietary intake of Zn is essential for various functions and metabolism. The uptake of Zn during its transport through the body is important for proper development of the three major accessory sex glands: the testis, epididymis, and prostate. It plays key roles in the initial stages of germ cell development and spermatogenesis, sperm cell development and maturation, ejaculation, liquefaction, the binding of spermatozoa and prostasomes, capacitation, and fertilization. The prostate releases more Zn into the seminal plasma during ejaculation, and it plays a significant role in sperm release and motility. During the maternal, labor, perinatal, and neonatal periods, the part of Zn is vital. The average dietary intake of Zn is in the range of 8-12 mg/day in developing countries during the maternal period. Globally, the dietary intake of Zn varies for pregnant and lactating mothers, but the average Zn intake is in the range of 9.6-11.2 mg/day. The absence of Zn and the consequences of this have been discussed using critical evidence. The events and functions of Zn related to successful fertilization have been summarized in detail. Briefly, our current review emphasizes the role of Zn at each stage of human reproduction, from the spermatogenesis process to childbirth. The role of Zn and its supplementation in in vitro fertilization (IVF) opens opportunities for future studies on reproductive biology.