Endocrine control of mucosal immunity in the female reproductive tract: impact of environmental disruptors

Effects of Ellagic Acid on Vaginal Innate Immune Mediators and HPV16 Infection In Vitro

Ellagic acid (EA) is a phenolic phytochemical found in many plants and their fruits. Vaginal epithelial cells are the first line of defense against pathogen invasion in the female reproductive tract and express antimicrobial peptides, including hBD2 and SLPI. This study investigated the in vitro effects of EA (1) on vaginal innate immunity using human vaginal epithelial cells, and (2) on HPV16 pseudovirus infection. Vaginal cells were cultured in the presence or absence of EA, and the expression of hBD2 and SLPI was determined at both transcriptional and translational levels. In addition, secretion of various cytokines and chemokines was measured. Cytotoxicity of EA was determined by CellTiter-blue and MTT assays. To investigate the ability of EA to inhibit HPV16 infection, EA was used to treat HEK-293FT cells in pre-attachment and adsorption steps. We found significant increases in both hBD2 mRNA (mean 2.9-fold at 12.5 µM EA, p < 0.001) and protein (mean 7.1-fold at 12.5 µM EA, p = 0.002) in response to EA. SLPI mRNA also increased significantly (mean 1.4-fold at 25 µM EA, p = 0.01), but SLPI protein did not. Secretion of IL-2 but not of other cytokines/chemokines was induced by EA in a dose-dependent manner. EA was not cytotoxic. At the pre-attachment step, EA at CC20 and CC50 showed a slight trend towards inhibiting HPV16 pseudovirus, but this was not significant. In summary, vaginal epithelial cells can respond to EA by producing innate immune factors, and at tested concentrations, EA is not cytotoxic. Thus, plant-derived EA could be useful as an immunomodulatory agent to improve vaginal health.

Changes in interleukin-2, -4, -6 and -8 expression in the postovulatory sow endometrium after artificial insemination based on conceived or failed to conceive

The establishment and maintenance of a pregnancy requires proper interaction between the endocrine and immune systems in the uterus. Therefore, it is crucial to understand how changes in endometrial cytokine levels facilitate reproduction. This study aimed to investigate how representative cytokines sequentially changed in the endometrium and whether conception could be attributed to these changes. In this study, artificial insemination was performed twice in 160 sows and ovulation was examined every 3 h using transrectal ultrasonography. Uterine endometrial tissues were obtained via repeated biopsies at 2, 4, 6, 8, 12, 16, and 20 h after ovulation and interleukin (IL)-2, IL-4, IL-6, and IL-8 expression was examined using real-time polymerase chain reaction. The conception rate was 91.9%. The IL-2 levels showed no differences in conception or time. The expression peaks of IL-4 and IL-6 were delayed in sows that failed to conceive within 4-6 h and 2 h, respectively, compared to those that did conceive. In sows that conceived, IL-8 was highest after 2 h, and no difference was observed at other time point, regardless of conception. In sows that failed to conceive, the increase in IL-8 levels might have been cancelled or terminated before the first sampling time. These results highlight the importance of timely increases and subsequent declines in the levels of some cytokines for the establishment of pregnancy. Differences in uterine capacity start just after ovulation; detection and correction of these deviations can improve the reproductive efficiency of sows.

Morphology of the immune cells in the wall of the human uterine tube and their possible impact on reproduction-uterine tube as a possible immune privileged organ

The uterine tube, as well as other parts of the upper female reproductive system, is immunologically unique in its requirements for tolerance to allogenic sperm and semi-allogenic embryos, yet responds to an array of sexually transmitted pathogens. To understand this dichotomy, there is a need to understand the functional morphology of immune cells in the wall of the uterine tube. Thus, we reviewed scientific literature regarding immune cells and the human uterine tube by using the scientific databases. The human uterine tube has a diverse population of immunocompetent cells representing both the innate and adaptive immune systems. We describe in detail the possible roles of cells of the mononuclear phagocyte system (macrophages and dendritic cells), T and B lymphocytes, natural killer cells, neutrophils and mast cells in association with the reproductive functions of uterine tubes. We are also discussing about the possible "immune privilege" of the uterine tube, as another mechanism to tolerate sperm and embryo without eliciting an inflammatory immune response. In uterine tube is not present an anatomical blood-tissue barrier between antigens and circulation. However, the immune cells of the uterine tube probably represent a type of "immunological barrier," which probably includes the uterine tube among the immunologically privileged organs. Understanding how immune cells in the female reproductive tract play roles in reproduction is essential to understand not only the mechanisms of gamete transport and fertilization as well as embryo transport through the uterine tube, but also in improving results from assisted reproduction.

Impact of progesterone on the immune system in women: a systematic literature review

PURPOSE

The immune system is influenced by many factors, including female sex hormones. The extent of this influence, however, is not completely understood so far. This systematic literature review aims at giving an overview of the existing concepts on how endogenous progesterone influences the female immune system along the menstrual cycle.

METHODS

The inclusion criteria were healthy female subjects in their reproductive age with a regular menstrual cycle. The exclusion criteria were exogenous progesterone, animal models, nonhealthy study populations and pregnancy. This led to 18 papers covered in this review. The search was performed using the databases EMBASE, Ovid MEDLINE and Epub, and the last search was conducted on September 18, 2020. Our findings were analyzed in four categories: cellular immune defense, humoral immune defense, objective and subjective clinical parameters.

RESULTS

We demonstrated that progesterone acts in an immunosuppressive way, favoring a Th-2-like cytokine profile. Further, we showed that progesterone inhibits mast cell degranulation and relaxes smooth muscle cells. Furthermore, we found supporting evidence for a so-called window of vulnerability after ovulation, where immune functions are lowered and mediated through progesterone.

CONCLUSION

The clinical relevance of these findings is not completely understood yet. As the sample sizes of included studies were rather small and the content of them was broad, further investigations are needed to define to which extent the described changes actually clinically meaningful, whether they are capable of influencing the female health and how these findings can be used to increase well-being.

Microbiota metabolites in the female reproductive system: Focused on the short-chain fatty acids

Several disorders have been linked to modifications in the gut microbial imbalance, intestinal epithelium, and host immune system. In this regard, microbiota derived short-chain fatty acids (SCFAs) play a key function in the regulation of histone deacetylases (HDACs), which affect modulation of immunity and regulation of inflammatory responses in the intestine and other organs. Studies examining the metabolites produced by polymicrobial bacterial vaginosis (BV) states and Lactobacillus-dominated microbiota have noted a dramatic reduction of lactic acid and a shift toward SCFA synthesis. Along with higher levels of SCFAs, acetate is typically the main metabolite in the cervicovaginal fluid of women with symptomatic bacterial vaginosis. The fact that SCFAs made by the vaginal microbiota have been shown to exhibit antibacterial and immune-modulating properties suggests that they may have promise as indicators of disease and/or disease susceptibility. In this review, we overview and summarize the current findings on the detrimental or protective roles of microbiota metabolites especially SCFAs in the health and disease of the female reproductive system.

Correlation of peripheral blood and endometrial immunophenotyping in ART: is peripheral blood sampling useful?

PURPOSE

Using a comprehensive flow cytometric panel, simultaneously obtained mid-luteal immunophenotypes from peripheral blood and endometrium were compared and values correlated. Is a peripheral blood evaluation of reproductive immunophenotype status meritorious relative to local endometrial evaluation to directly assess the peri-implantation environment?

METHODS

Fifty-five patients had a mid-luteal biopsy to assess the local endometrial immunophenotype, while simultaneously providing a peripheral blood sample for analysis. Both samples were immediately assessed using a comprehensive multi-parameter panel, and lymphocyte subpopulations were described and compared.

RESULTS

Distinct lymphocyte proportions and percentage differences were noted across the two compartments, confirming the hypothesis that they are distinct environments. The ratio of CD4 + to CD8 + T cells were reversed between the two compartments, as were Th1 and Th2-type CD4 + T cell ratios. Despite these differences, some direct relationships were noted. Positive Pearson correlations were found between the levels of CD57 + expressing natural killer cells, CD3 + NK-T cells and CD4 + Th1 cells in both compartments.

CONCLUSIONS

Flow cytometric evaluation provides a rapid and objective analysis of lymphocyte subpopulations. Endometrial biopsies have become the gold standard technique to assess the uterine immunophenotype in adverse reproductive outcome, but there may still a place for peripheral blood evaluation in this context. The findings demonstrate significant variations in cellular proportions across the two regions, but some positive correlations are present. Immunological assessment of these specific peripheral blood lymphocyte subtypes may provide insight into patients with potential alterations of the uterine immune environment, without the risks and inconveniences associated with an invasive procedure.

Genital inflammatory status and the innate immune response to contraceptive initiation

PROBLEM

Data on the effects of contraceptives on female genital tract (FGT) immune mediators are inconsistent, possibly in part due to pre-existing conditions that influence immune mediator changes in response to contraceptive initiation.

METHODS

This study included 161 South African women randomised to injectable depot medroxyprogesterone acetate (DMPA-IM), copper intrauterine device (IUD), or levonorgestrel (LNG) implant in the Evidence for Contraceptive Options and HIV Outcomes (ECHO) trial. We measured thirteen cytokines and antimicrobial peptides previously associated with HIV acquisition in vaginal swabs using Luminex and ELISA, before, and at 1 and 3 months after contraceptive initiation. Women were grouped according to an overall baseline inflammatory profile. We evaluated modification of the relationships between contraceptives and immune mediators by baseline inflammation, demographic, and clinical factors.

RESULTS

Overall, LNG implant and copper IUD initiation were associated with increases in inflammatory cytokines, while no changes were observed following DMPA-IM initiation. However, when stratifying by baseline inflammatory profile, women with low baseline inflammation in all groups experienced significant increases in inflammatory cytokines, while those with a high baseline inflammatory profile experienced no change or decreases in inflammatory cytokines.

CONCLUSION

We conclude that pre-contraceptive initiation immune profile modifies the effect of contraceptives on the FGT innate immune response.

Lactobacillus, glycans and drivers of health in the vaginal microbiome

A microbiome consists of microbes and their genomes, encompassing bacteria, viruses, fungi, protozoa, archaea, and eukaryotes. These elements interact dynamically in the specific environment in which they reside and evolve. In the past decade, studies of various microbiomes have been prevalent in the scientific literature, accounting for the shift from culture-dependent to culture-independent identification of microbes using new high-throughput sequencing technologies that decipher their composition and sometimes provide insights into their functions. Despite tremendous advances in understanding the gut microbiome, relatively little attention has been devoted to the vaginal environment, notably regarding the ubiquity and diversity of glycans which denote the significant role they play in the maintenance of homeostasis. Hopefully, emerging technologies will aid in the determination of what is a healthy vaginal microbiome, and provide insights into the roles of Lactobacillus, glycans and microbiome-related drivers of health and disease.

The Effect of Low Doses of Zearalenone (ZEN) on the Bone Marrow Microenvironment and Haematological Parameters of Blood Plasma in Pre-Pubertal Gilts

The aim of this study was to determine whether low doses of zearalenone (ZEN) influence the carry-over of ZEN and its metabolites to the bone marrow microenvironment and, consequently, haematological parameters. Pre-pubertal gilts (with a body weight of up to 14.5 kg) were exposed to daily ZEN doses of 5 μg/kg BW (group ZEN5, n = 15), 10 μg/kg BW (group ZEN10, n = 15), 15 μg/kg BW (group ZEN15, n = 15), or were administered a placebo (group C, n = 15) throughout the entire experiment. Bone marrow was sampled on three dates (exposure dates 7, 21, and 42—after slaughter) and blood for haematological analyses was sampled on 10 dates. Significant differences in the analysed haematological parameters (WBC White Blood Cells, MONO—Monocytes, NEUT—Neutrophils, LYMPH—Lymphocytes, LUC—Large Unstained Cells, RBC—Red Blood Cells, HGB—Haemoglobin, HCT—Haematocrit, MCH—Mean Corpuscular Volume, MCHC—Mean Corpuscular Haemoglobin Concentrations, PLT—Platelet Count and MPV—Mean Platelet Volume) were observed between groups. The results of the experiment suggest that exposure to low ZEN doses triggered compensatory and adaptive mechanisms, stimulated the local immune system, promoted eryptosis, intensified mycotoxin biotransformation processes in the liver, and produced negative correlations between mycotoxin concentrations and selected haematological parameters.

Occurrence of Zearalenone and Its Metabolites in the Blood of High-Yielding Dairy Cows at Selected Collection Sites in Various Disease States

Zearalenone (ZEN) and its metabolites, alpha-zearalenol (α-ZEL) and beta-zearalenol (β-ZEL), are ubiquitous in plant materials used as feed components in dairy cattle diets. The aim of this study was to confirm the occurrence of ZEN and its selected metabolites in blood samples collected from different sites in the hepatic portal system (posthepatic-external jugular vein EJV; prehepatic-abdominal subcutaneous vein ASV and median caudal vein MCV) of dairy cows diagnosed with mastitis, ovarian cysts and pyometra. The presence of mycotoxins in the blood plasma was determined with the use of combined separation methods involving immunoaffinity columns, a liquid chromatography system and a mass spectrometry system. The parent compound was detected in all samples collected from diseased cows, whereas α-ZEL and β-ZEL were not identified in any samples, or their concentrations were below the limit of detection (LOD). Zearalenone levels were highest in cows with pyometra, where the percentage share of average ZEN concentrations reached 44%. Blood sampling sites were arranged in the following ascending order based on ZEN concentrations: EJV (10.53 pg/mL, 44.07% of the samples collected from this site), ASV (14.20 pg/mL, 49.59% of the samples) and MCV (26.67 pg/mL, 67.35% of the samples). The results of the study indicate that blood samples for toxicological analyses should be collected from the MCV (prehepatic vessel) of clinically healthy cows and/or cows with subclinical ZEN mycotoxicosis. This sampling site increases the probability of correct diagnosis of subclinical ZEN mycotoxicosis.

Concentration of Zearalenone, Alpha-Zearalenol and Beta-Zearalenol in the Myocardium and the Results of Isometric Analyses of the Coronary Artery in Prepubertal Gilts

The carry-over of zearalenone (ZEN) to the myocardium and its effects on coronary vascular reactivity in vivo have not been addressed in the literature to date. Therefore, the objective of this study was to verify the hypothesis that low ZEN doses (MABEL, NOAEL and LOAEL) administered per os to prepubertal gilts for 21 days affect the accumulation of ZEN, α-ZEL and β-ZEL in the myocardium and the reactivity of the porcine coronary arteries to vasoconstrictors: acetylcholine, potassium chloride and vasodilator sodium nitroprusside. The contractile response to acetylcholine in the presence of a cyclooxygenase (COX) inhibitor, indomethacin and / or an endothelial nitric oxide synthase (e-NOS) inhibitor, L-NAME was also studied. The results of this study indicate that the carry-over of ZEN and its metabolites to the myocardium is a highly individualized process that occurs even at very low mycotoxin concentrations. The concentrations of the accumulated ZEN metabolites are inversely proportional to each other due to biotransformation processes. The levels of vasoconstrictors, acetylcholine and potassium chloride, were examined in the left anterior descending branch of the porcine coronary artery after oral administration of ZEN. The LOAEL dose clearly decreased vasoconstriction in response to both potassium chloride and acetylcholine (P < 0.05 for all values) and increased vasodilation in the presence of sodium nitroprusside (P = 0.021). The NOAEL dose significantly increased vasoconstriction caused by acetylcholine (P < 0.04), whereas the MABEL dose did not cause significant changes in the vascular response. Unlike higher doses of ZEN, 5 μg/kg had no negative influence on the vascular system.

Concentrations of zearalenone and its metabolites in female wild boars from woodlands and farmlands

As a valuable food base and safe shelter, large agricultural fields create favourable living conditions for wild boars for most of the year. The occurrence of mould in these fields, causing hormonal disturbances, may lead to a lower age of sexual maturity and a prolonged breeding season, and therefore, the population growth in farmlands can be markedly higher than that in extensive woodlands. This study was initiated because of reproductive cycle disturbances in wild boar populations, which were presumably linked with habitat and food types, especially rotten maize. To determine if the major sources of zearalenone (ZEN) in female wild boars are maize cobs infected with mycotoxins, we compared the concentrations of ZEN and its metabolites in organs, tissues and body fluids of wild boars hunted in extensive maize fields and in extensive woodlands where no large maize fields were located within a distance of several km. Samples of blood, bile, liver, kidneys, muscles, urine, stomach and colon contents as well as ovaries from young female wild boars (40-60 kg) were collected in 2011-2014 and prepared for liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The results showed that ZEN was present in most of the samples, from both farmlands and woodlands, but its concentration within individual types of the analysed body fluids or tissues differed depending mainly on habitat type. In nearly all the analysed cases, higher concentrations of ZEN and its derivatives were detected in the samples collected from wild boars in farmlands, suggesting that wild boars living and feeding in extensive maize fields take in markedly higher amounts of mycoestrogens.

Endocrine Disruptor Compounds-A Cause of Impaired Immune Tolerance Driving Inflammatory Disorders of Pregnancy?

Endocrine disrupting compounds (EDCs) are prevalent and ubiquitous in our environment and have substantial potential to compromise human and animal health. Amongst the chronic health conditions associated with EDC exposure, dysregulation of reproductive function in both females and males is prominent. Human epidemiological studies demonstrate links between EDC exposure and infertility, as well as gestational disorders including miscarriage, fetal growth restriction, preeclampsia, and preterm birth. Animal experiments show EDCs administered during gestation, or to either parent prior to conception, can interfere with gamete quality, embryo implantation, and placental and fetal development, with consequences for offspring viability and health. It has been presumed that EDCs operate principally through disrupting hormone-regulated events in reproduction and fetal development, but EDC effects on maternal immune receptivity to pregnancy are also implicated. EDCs can modulate both the innate and adaptive arms of the immune system, to alter inflammatory responses, and interfere with generation of regulatory T (Treg) cells that are critical for pregnancy tolerance. Effects of EDCs on immune cells are complex and likely exerted by both steroid hormone-dependent and hormone-independent pathways. Thus, to better understand how EDCs impact reproduction and pregnancy, it is imperative to consider how immune-mediated mechanisms are affected by EDCs. This review will describe evidence that several EDCs modify elements of the immune response relevant to pregnancy, and will discuss the potential for EDCs to disrupt immune tolerance required for robust placentation and optimal fetal development.

Hypothetical roadmap towards endometriosis: prenatal endocrine-disrupting chemical pollutant exposure, anogenital distance, gut-genital microbiota and subclinical infections

BACKGROUND

Endometriosis is a gynaecological hormone-dependent disorder that is defined by histological lesions generated by the growth of endometrial-like tissue out of the uterus cavity, most commonly engrafted within the peritoneal cavity, although these lesions can also be located in distant organs. Endometriosis affects ~10% of women of reproductive age, frequently producing severe and, sometimes, incapacitating symptoms, including chronic pelvic pain, dysmenorrhea and dyspareunia, among others. Furthermore, endometriosis causes infertility in ~30% of affected women. Despite intense research on the mechanisms involved in the initial development and later progression of endometriosis, many questions remain unanswered and its aetiology remains unknown. Recent studies have demonstrated the critical role played by the relationship between the microbiome and mucosal immunology in preventing sexually transmitted diseases (HIV), infertility and several gynaecologic diseases.

OBJECTIVE AND RATIONALE

In this review, we sought to respond to the main research question related to the aetiology of endometriosis. We provide a model pointing out several risk factors that could explain the development of endometriosis. The hypothesis arises from bringing together current findings from large distinct areas, linking high prenatal exposure to environmental endocrine-disrupting chemicals with a short anogenital distance, female genital tract contamination with the faecal microbiota and the active role of genital subclinical microbial infections in the development and clinical progression of endometriosis.

SEARCH METHODS

We performed a search of the scientific literature published until 2019 in the PubMed database. The search strategy included the following keywords in various combinations: endometriosis, anogenital distance, chemical pollutants, endocrine-disrupting chemicals, prenatal exposure to endocrine-disrupting chemicals, the microbiome of the female reproductive tract, microbiota and genital tract, bacterial vaginosis, endometritis, oestrogens and microbiota and microbiota-immune system interactions.

OUTCOMES

On searching the corresponding bibliography, we found frequent associations between environmental endocrine-disrupting chemicals and endometriosis risk. Likewise, recent evidence and hypotheses have suggested the active role of genital subclinical microbial infections in the development and clinical progression of endometriosis. Hence, we can envisage a direct relationship between higher prenatal exposure to oestrogens or estrogenic endocrine-disrupting compounds (phthalates, bisphenols, organochlorine pesticides and others) and a shorter anogenital distance, which could favour frequent postnatal episodes of faecal microbiota contamination of the vulva and vagina, producing cervicovaginal microbiota dysbiosis. This relationship would disrupt local antimicrobial defences, subverting the homeostasis state and inducing a subclinical inflammatory response that could evolve into a sustained immune dysregulation, closing the vicious cycle responsible for the development of endometriosis.

WIDER IMPLICATIONS

Determining the aetiology of endometriosis is a challenging issue. Posing a new hypothesis on this subject provides the initial tool necessary to design future experimental, clinical and epidemiological research that could allow for a better understanding of the origin of this disease. Furthermore, advances in the understanding of its aetiology would allow the identification of new therapeutics and preventive actions.

Oral exposure to bisphenols induced food intolerance and colitis in vivo by modulating immune response in adult mice

Bisphenol (BP) A, a known food contaminant, is a possible risk factor in the epidemic of non-communicable diseases (NCD) including food intolerance and inflammatory bowel diseases (IBD). Regulatory restrictions regarding BPA usage led to BPA removal and replacement by poorly described substitutes, like BPS or BPF (few data on occurrence in food and human samples and biological effect). Oral tolerance protocol to ovalbumin (OVA) in WT mice and Il10^-/- mice prone to IBD were used respectively to address immune responses towards food and microbial luminal antigens following BP oral exposure. Both mice models were orally exposed for five weeks to BPA, BPS or BPF at 0.5, 5 and 50 μg/kg of body weight (bw)/day (d). Oral exposure to BPs at low doses (0.5 and 5 μg/kg bw/d) impaired oral tolerance as indicated by higher humoral and pro-inflammatory cellular responses in OVA-tolerized mice. However, only BPF exacerbate colitis in Il10^-/- prone mice associated with a defect of fecal IgA and increased secretion of TNF-α in colon. These findings provide a unique comparative study on effects of adult oral exposure to BPs on immune responses and its consequences on NCD related to intestinal luminal antigen development.

The Effect of Different Doses of Zearalenone in Feed on the Bioavailability of Zearalenone and Alpha-Zearalenol, and the Concentrations of Estradiol and Testosterone in the Peripheral Blood of Pre-Pubertal Gilts

The objective of this study was to determine the effect of long-term (48 days), per os administration of specific zearalenone (ZEN) doses (20 and 40 μg ZEN/kg BW in experimental groups EI and EII, which were equivalent to 200% and 400% of the upper range limit of the no-observed-adverse-effect-level (NOAEL), respectively) on the bioavailability of ZEN and the rate of changes in estradiol and testosterone concentrations in the peripheral blood of pre-pubertal gilts. ZEN and α-ZEL levels were similar until day 28. After day 28, α-ZEL concentrations increased significantly in group EI, whereas a significant rise in ZEN levels was noted in group EII. The presence of estradiol in peripheral blood plasma was not observed until day 20 of the experiment. Spontaneous secretion of estradiol was minimal, and it was determined at very low levels of up to 10 pg/mL in EI and EII groups. Testosterone concentrations ranged from 4 to 9 ng/mL in all groups. A decrease in the concentrations of both analyzed hormones was reported in the last stage of the experiment. The results of the experiment indicate that: (i) The bioavailability of ZEN in peripheral blood has low diagnostic value, (ii) exposure to low doses of ZEN induces minor changes in the concentrations of the analyzed hormones, which could lead to situational supraphysiological hormone levels and changes in endogenous hormonal balance.

Advances in understanding mechanisms of long-term sperm storage-the soft-shelled turtle model

Long-term sperm storage is a special reproductive strategy, which can extend the time window between mating and fertilization in some animal species. Spermatozoa of the soft-shelled turtle, Pelodiscus sinensis, can be stored in the epididymis and oviduct for at least six months and one year, respectively. How spermatozoa can be stored in vivo for such a prolonged period is yet to be explained. We analyze the mechanisms that contribute to long-term sperm storage in P. sinensis, and compare them with other species from three different perspectives: the spermatozoon itself, the storage microenvironment and the interaction between the spermatozoon and microenvironment. Characteristics of soft-shelled turtle spermatozoa itself, such as the huge cytoplasmic droplet with its content of several large lipid droplets (LDs) and onion-like mitochondira, facilitate long-term sperm storage. The microenvironment of reproductive tract, involving in the secretions, structural barriers, exosomes, androgen receptors, Toll-like receptors and survival factor Bcl-2, are important for the maintenance of spermatozoa long-term storage. Sperm heads are always embedded among the oviductal cilia and even intercalate into the apical hollowness of the ciliated cells, indicating that the ciliated cells support the stored spermatozoa. RNA seq is firstly used to detect the molecular mechanism of sperm storage, which shows that autophagy, apoptosis and immune take part in the long-term sperm storage in this species.

The relationship between sex hormones, the vaginal microbiome and immunity in HIV-1 susceptibility in women

The role of sex hormones in regulating immune responses in the female genital tract has been recognized for decades. More recently, it has become increasingly clear that sex hormones regulate susceptibility to sexually transmitted infections through direct and indirect mechanisms involving inflammation and immune responses. The reproductive cycle can influence simian/human immunodeficiency virus (SHIV) infections in primates and HIV-1 infection in ex vivo cervical tissues from women. Exogenous hormones, such as those found in hormonal contraceptives, have come under intense scrutiny because of the increased susceptibility to sexually transmitted infections seen in women using medroxyprogesterone acetate, a synthetic progestin-based contraceptive. Recent meta-analyses concluded that medroxyprogesterone acetate enhanced HIV-1 susceptibility in women by 40%. In contrast, estradiol-containing hormonal contraceptives were not associated with increased susceptibility and some studies reported a protective effect of estrogen on HIV/SIV infection, although the underlying mechanisms remain incompletely understood. Recent studies describe a key role for the vaginal microbiota in determining susceptibility to sexually transmitted infections, including HIV-1. While Lactobacillus spp.-dominated vaginal microbiota is associated with decreased susceptibility, complex microbiota, such as those seen in bacterial vaginosis, correlates with increased susceptibility to HIV-1. Interestingly, sex hormones are inherently linked to microbiota regulation in the vaginal tract. Estrogen has been postulated to play a key role in establishing a Lactobacillus-dominated microenvironment, whereas medroxyprogesterone acetate is linked to hypo-estrogenic effects. The aim of this Review is to contribute to a better understanding of the sex-hormone-microbiome-immunity axis, which can provide key information on the determinants of HIV-1 susceptibility in the female genital tract and, consequently, inform HIV-1 prevention strategies.

Mycotoxin levels in the digestive tissues of immature gilts exposed to zearalenone and deoxynivalenol

Most plant materials are contaminated with small doses of Fusarium mycotoxins and its modified forms that exert subclinical toxic effects on humans and animals. The aim of this study was to evaluate the carry-over of zearalenone and deoxynivalenol (pure parent compounds) to intestinal and liver tissues during 6 weeks of exposure to mycotoxins administered per os to gilts. The experiment was performed on 36 gilts with average body weight of 25 ± 2 kg, divided into 2 groups: an experimental group (group E, administered zearalenone at 40 μg/kg BW and deoxynivalenol at 12 μg/kg BW daily with feed) and a control group administered placebo. Tissue saturation with mycotoxins was analysed by liquid chromatography in samples collected at weekly intervals. Six gilts were euthanized in each week of the study. The conducted analyses revealed: (i) a non-uniform increase in zearalenone levels in the duodenum, jejunum, ascending colon and the liver; and (ii) an increase in deoxynivalenol levels, mainly in the ileum, caecum, ascending colon and the transverse colon, and a minor increase in the liver. The degree of tissue saturation was determined by the type of mycotoxin, but not by the time of exposure.

Growth performance, selected blood biochemical parameters and body weights of pre-pubertal gilts fed diets supplemented with different doses of zearalenone (ZEN)

The aim of this study was to determine whether exposure to low doses of zearalenone (ZEN) induces changes in the serum biochemical profile and body weights (BW). Pre-pubertal gilts (with BW of up to 14.5 kg) were administered ZEN in daily doses of 5 μg/kg BW (group 1, n = 15), 10 μg/kg BW (group 2, n = 15), 15 μg/kg BW (group 3, n = 15) or placebo (control group C, n = 15) throughout the experiment. Blood was sampled for analysis on 10 dates (at five-day intervals). Minor but statistically significant differences in the analysed serum biochemical parameters (ALT, AST, ALP, total cholesterol, total bilirubin, glucose, total protein, iron, BUN and urea) were observed in the studied groups. The biochemical parameters of the analysed gilts indicate that the maintenance of homeostasis and biotransformation of ZEN require considerable energy expenditure. Beginning on the fourth analytical date, BW gains were consistently higher in the experimental groups than in group C. The observed decrease in glucose and total protein levels can probably be attributed to higher BW gains and the ongoing ZEN biotransformation processes in the enterocytes and the liver.

Activity of Zearalenone in the Porcine Intestinal Tract

This study demonstrates that low doses (somewhat above the No Observed Adverse Effect Level, NOAEL) of the mycoestrogen zearalenone (ZEN) and its metabolites display multispecificity towards various biological targets in gilts. The observed responses in gilts were surprising. The presence of ZEN and zearalenols (ZELs) did not evoke a response in the porcine gastrointestinal tract, which was attributed to dietary tolerance. Lymphocyte proliferation was intensified in jejunal mesenteric lymph nodes, and lymphocyte counts increased in the jejunal epithelium with time of exposure. In the distal digestive tract, fecal bacterial counts decreased, the activity of fecal bacterial enzymes and lactic acid bacteria increased, and cecal water was characterized by higher genotoxicity. The accompanying hyperestrogenism led to changes in mRNA activity of selected enzymes (cytochrome P450, hydroxysteroid dehydrogenases, nitric oxide synthases) and receptors (estrogen and progesterone receptors), and it stimulated post-translational modifications which play an important role in non-genomic mechanisms of signal transmission. Hyperestrogenism influences the regulation of the host's steroid hormones (estron, estradiol and progesteron), it affects the virulence of bacterial genes encoding bacterial hydroxysteroid dehydrogenases (HSDs), and it participates in detoxification processes by slowing down intestinal activity, provoking energy deficits and promoting antiporter activity at the level of enterocytes. In most cases, hyperestrogenism fulfils all of the above roles. The results of this study indicate that low doses of ZEN alleviate inflammatory processes in the digestive system, in particular in the proximal and distal intestinal tract, and increase body weight gains in gilts.

The Effect of Low Monotonic Doses of Zearalenone on Selected Reproductive Tissues in Pre-Pubertal Female Dogs--A Review

The growing interest in toxic substances combined with advancements in biological sciences has shed a new light on the problem of mycotoxins contaminating feeds and foods. An interdisciplinary approach was developed by identifying dose-response relationships in key research concepts, including the low dose theory of estrogen-like compounds, hormesis, NOAEL dose, compensatory response and/or food tolerance, and effects of exposure to undesirable substances. The above considerations increased the researchers’ interest in risk evaluation, namely: (i) clinical symptoms associated with long-term, daily exposure to low doses of a toxic compound; and (ii) dysfunctions at cellular or tissue level that do not produce clinical symptoms. Research advancements facilitate the extrapolation of results and promote the use of novel tools for evaluating the risk of exposure, for example exposure to zearalenone in pre-pubertal female dogs. The arguments presented in this paper suggest that low doses of zearalenone in commercial feeds stimulate metabolic processes and increase weight gains. Those processes are accompanied by lower proliferation rates in the ovaries, neoangiogenesis and vasodilation in the ovaries and the uterus, changes in the steroid hormone profile, and changes in the activity of hydroxysteroid dehydrogenases. All of the above changes result from exogenous hyperestrogenizm.

Zearalenone in the Intestinal Tissues of Immature Gilts Exposed per os to Mycotoxins

Zearalenone and its metabolites, α-zearalenol and β-zearalenol, demonstrate estradiol-like activity and disrupt physiological functions in animals. This article evaluates the carryover of zearalenone and its selected metabolites from the digesta to intestinal walls (along the entire intestines) in pre-pubertal gilts exposed to low doses of zearalenone over long periods of time. The term “carryover” describes the transfer of mycotoxins from feed to edible tissues, and it was used to assess the risk of mycotoxin exposure for consumers. The experimental gilts with body weight of up to 25 kg were per os administered zearalenone at a daily dose of 40 μg/kg BW (Group E, n = 18) or placebo (Group C, n = 21) over a period of 42 days. In the first weeks of exposure, the highest values of the carryover factor were noted in the duodenum and the jejunum. In animals receiving pure zearalenone, the presence of metabolites was not determined in intestinal tissues. In the last three weeks of the experiment, very high values of the carryover factor were observed in the duodenum and the descending colon. The results of the study indicate that in animals exposed to subclinical doses of zearalenone, the carryover factor could be determined by the distribution and expression of estrogen receptor beta.

Sex Hormones Coordinate Neutrophil Immunity in the Vagina by Controlling Chemokine Gradients

Estradiol-based contraceptives and hormonal replacement therapy predispose women to Candida albicans infections. Moreover, during the ovulatory phase (high estradiol), neutrophil numbers decrease in the vaginal lumen and increase during the luteal phase (high progesterone). Vaginal secretions contain chemokines that drive neutrophil migration into the lumen. However, their expression during the ovarian cycle or in response to hormonal treatments are controversial and their role in vaginal defense remains unknown.To investigate the transepithelial migration of neutrophils, we used adoptive transfer of Cxcr2(-/-) neutrophils and chemokine immunofluorescence quantitative analysis in response to C. albicans vaginal infection in the presence of hormones.Our data show that the Cxcl1/Cxcr2 axis drives neutrophil transepithelial migration into the vagina. Progesterone promotes the Cxcl1 gradient to favor neutrophil migration. Estradiol disrupts the Cxcl1 gradient and favors neutrophil arrest in the vaginal stroma; as a result, the vagina becomes more vulnerable to pathogens.

Sperm storage and spermatozoa interaction with epithelial cells in oviduct of Chinese soft-shelled turtle, Pelodiscus sinensis

Spermatozoa are known to be stored within the female genital tract after mating in various species to optimize timing of reproductive events such as copulation, fertilization, and ovulation. The mechanism supporting long-term sperm storage is still unclear in turtles. The aim of this study was to investigate the interaction between the spermatozoa and oviduct in Chinese soft-shelled turtle by light and electron microscopy to reveal the potential cytological mechanism of long-term sperm storage. Spermatozoa were stored in isthmus, uterine, and vagina of the oviduct throughout the year, indicating long-term sperm storage in vivo. Sperm heads were always embedded among the cilia and even intercalated into the apical hollowness of the ciliated cells in the oviduct mucosal epithelium. The stored spermatozoa could also gather in the gland conduit. There was no lysosome distribution around the hollowness of the ciliated cell, suggesting that the ciliated cells of the oviduct can support the spermatozoa instead of phagocytosing them in the oviduct. Immune cells were sparse in the epithelium and lamina propria of oviduct, although few were found inside the blood vessel of mucosa, which may be an indication of immune tolerance during sperm storage in the oviduct of the soft-shelled turtle. These characteristics developed in the turtle benefited spermatozoa survival for a long time as extraneous cells in the oviduct of this species. These findings would help to improve the understanding of reproductive regularity and develop strategies of species conservation in the turtle. The Chinese soft-shelled turtle may be a potential model for uncovering the mechanism behind the sperm storage phenomenon.

Omega 3 and omega 6 fatty acids in human and animal health: an African perspective

Lipids are essential for plant and animal development, growth and nutrition and play critical roles in health and reproduction. The dramatic increase in the human population has put increasing pressure on human food sources, especially of those sources of food which contain adequate levels of polyunsaturated fatty acids (PUFAs) and more importantly, sources of food which have favorable ratios of the n-3 (18-carbon, α-linolenic acid, ALA) to n-6 (18-carbon linoleic acid, LA) PUFAs. Recent studies have demonstrated the beneficial effects of the n-3 PUFAs in diets as well as potentially negative effects of excessive levels of n-6 PUFAs in diets. This review discusses these human health issues relating to changes in diets based on environmental and industrial changes as well as strategies in East Africa for improving lipid composition of food using indigenous sources.

Food intolerance at adulthood after perinatal exposure to the endocrine disruptor bisphenol A

The food contaminant bisphenol A (BPA) is pointed out as a risk factor in development of food allergy and food intolerance, two adverse food reactions increasing worldwide. We evaluated the consequences of perinatal exposure to low doses of BPA on immune-specific response to the food antigen ovalbumin (OVA) at adulthood. Perinatal exposure to BPA (0.5, 5, or 50 μg/kg/d) from 15th day of gravidity to pups weaning resulted in an increase of anti-OVA IgG titers at all BPA dosages in OVA-tolerized rats, and at 5 μg/kg/d in OVA-immunized rats compared to control rats treated with vehicle. In BPA-treated and OVA-tolerized rats, increased anti-OVA IgG titers were associated with higher IFNγ secretion by the spleen. This result is in accordance with the increase of activated CD4(+)CD44(high)CD62L(low) T lymphocytes observed in spleen of BPA-exposed rats compared to controls. Finally, when BPA-treated OVA-tolerized rats were orally challenged with OVA, colonic inflammation occurred, with neutrophil infiltration, increased IFNγ, and decreased TGFβ. We show that perinatal exposure to BPA altered oral tolerance and immunization to dietary antigens (OVA). In summary, the naive immune system of neonate is vulnerable to low doses of BPA that trigger food intolerance later in life.

The effect of low doses of zearalenone and its metabolites on progesterone and 17β-estradiol concentrations in peripheral blood and body weights of pre-pubertal female Beagle dogs

The experiment involved 30 clinically healthy female Beagle dogs aged approximately 70 days with estimated initial body weight (BW) of 8 kg. The animals were randomly divided into two experimental groups (EI and EII) and a control group of 10 animals each. Group EI was intoxicated with 50 μg zearalenone/kg BW per os for 42 days, group EII received 75 μg zearalenone/kg BW per os for 42 days, and the control group was administered placebo per os for 42 days. The animals were weighed, and blood samples for analyses of the concentrations of zearalenone, its metabolites, progesterone and 17β-estradiol were collected seven times at seven-day intervals, one hour after mycotoxin administration. Biotransformation of zearalenone was observed in all groups throughout the experiment, and the highest percentage share of α-zearalenol was reported in group EII on the last five sampling dates (0.637-0.788 ng/ml, i.e. percentage share of 57.96-73.64%). The above had a significant influence on the non-physiological concentrations of progesterone and 17β-estradiol in both experimental (E) groups throughout the experiment. The lowest progesterone levels (0.131 ng/ml) were observed in group EII during the last test, and high concentrations of 17β-estradiol were found in group EII on the last two sampling dates (17.434 and 21.581 ng/ml, respectively) in comparison with control. Inhibited proliferation, manifested by a slower rate of body weight gain, was observed on the last but one day of zearalenone administration in both experimental groups. Our results indicate that NOAEL doses have stimulating/adaptive effects, whereas doses above NOAEL values suggest that even very low zearalenone doses can act as endocrine disruptors with regard to progesterone and 17β-estradiol.

What should it take to describe a substance or product as 'sperm-safe'

BACKGROUND

Male reproductive potential continues to be adversely affected by many environmental, industrial and pharmaceutical toxins. Pre-emptive testing for reproductive toxicological (side-)effects remains limited, or even non-existent. Many products that come into direct contact with spermatozoa lack adequate testing for the absence of adverse effects, and numerous products that are intended for exposure to spermatozoa have only a general assumption of safety based on the absence of evidence of actual harm. Such assumptions can have unfortunate adverse impacts on at-risk individuals (e.g. couples who are trying to conceive), illustrating a clear need for appropriate up-front testing to establish actual 'sperm safety'.

METHODS

After compiling a list of general areas within the review's scope, relevant literature and other information was obtained from the authors' personal professional libraries and archives, and supplemented as necessary using PubMed and Google searches. Review by co-authors identified and eliminated errors of omission or bias.

RESULTS

This review provides an overview of the broad range of substances, materials and products that can affect male fertility, especially through sperm fertilizing ability, along with a discussion of practical methods and bioassays for their evaluation. It is concluded that products can only be claimed to be 'sperm-safe' after performing objective, properly designed experimental studies; extrapolation from supposed predicate products or other assumptions cannot be trusted.

CONCLUSIONS

We call for adopting the precautionary principle, especially when exposure to a product might affect not only a couple's fertility potential but also the health of resulting offspring and perhaps future generations.

Female sex hormones regulate the Th17 immune response to sperm and Candida albicans

STUDY QUESTION

What role do female sex hormones play in the antisperm immune response?

SUMMARY ANSWER

We found that sperm induce a Th17 immune response and that estradiol down-regulates the antisperm Th17 response by dendritic cells.

WHAT IS KNOWN ALREADY

Estradiol down-regulates the immune response to several pathogens and impairs the triggering of dendritic cell maturation by microbial products.

STUDY DESIGN, SIZE, DURATION

Ex vivo and in vivo murine models of vaginal infection with sperm and Candida albicans were used to study the induction of Th17 and its hormonal regulation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We analyzed the induction of Th17 cytokines and T cells in splenocytes obtained from BALB/c mice challenged with sperm and C. albicans. For the in vivo vaginal infection models, we used ovariectomized mice treated with vehicle, estradiol or progesterone, and we assessed the effect of these hormones on the immune response in the lymph nodes.

MAIN RESULTS AND THE ROLE OF CHANCE

Th17 cytokines and T cells were induced by sperm antigens in both ex vivo and in vivo experiments. Estrus levels of estradiol down-regulated the Th17 response to sperm and C. albicans in vivo.

LIMITATIONS, REASONS FOR CAUTION

This study was conducted using murine models; whether or not the results are applicable to humans is not known.

WIDER IMPLICATIONS OF THE FINDINGS

Our results describe an adaptive mechanism that reconciles immunity and reproduction and further explains why unregulated Th17 could be linked to infertility and recurrent infections.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by research grants from the Instituto de Salud Carlos III (ISCIII) (PI10/00897) and Fundación Mutua Madrileña to M.R. M.R. holds a Miguel Servet contract from the ISCIII (CP08/00228). M.A.M.-F. was supported by (ISCIII) INTRASALUD PI09/02029. We have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

Not required.

Estradiol downregulates NF-κb translocation by Ikbkg transcriptional repression in dendritic cells

To reconcile immunity and reproduction, females must allow spermatozoa to survive and control the presence of commensal microbiota and sexually transmitted pathogens during ovulation. Female steroid sex hormones exert a powerful effect on the immune system, as do the hormonal changes associated with the ovarian cycle. Dendritic cells (DCs) are immunological sentinels that link innate immunity to adaptive immunity. Upon exposure to microbial invaders in tissue, they undergo a maturational process that culminates in the lymph nodes and activates T-cell-specific immune responses. Estradiol, which is highly expressed during ovulation, has an effect on the maturation of DCs, although the molecular mechanism remains elusive. We detected that estradiol regulates expression of Ikbkg in DCs and modulates nuclear factor-κb translocation to the nucleus, thus explaining the reduced DC function observed during ovulation. This change may be an adaptive mechanism to reconcile control of infection and reproductive functions.

Preventing HIV infection in women

Although the number of new infections has declined recently, women still constitute almost half of the world's 34 million people with HIV infection, and HIV remains the leading cause of death among women of reproductive age. Prevention research has made considerable progress during the past few years in addressing the biological, behavioral, and social factors that influence women's vulnerability to HIV infection. Nevertheless, substantial work still must be performed to implement scientific advancements and to resolve many questions that remain. This article highlights some of the recent advances and persistent gaps in HIV prevention research for women and outlines key research and policy priorities.