Microbial colonization of follicular fluid: alterations in cytokine expression and adverse assisted reproduction technology outcomes

Microbiome in Female Reproductive Health: Implications for Fertility and Assisted Reproductive Technologies

The microbiome plays a critical role in the process of conception and the outcomes of pregnancy. Disruptions in microbiome homeostasis in women of reproductive age can lead to various pregnancy complications, which significantly impact maternal and fetal health. Recent studies have associated the microbiome in the female reproductive tract (FRT) with assisted reproductive technology (ART) outcomes, and restoring microbiome balance has been shown to improve fertility in infertile couples. This review provides an overview of the role of the microbiome in female reproductive health, including its implications for pregnancy outcomes and ARTs. Additionally, recent advances in the use of microbial biomarkers as indicators of pregnancy disorders are summarized. A comprehensive understanding of the characteristics of the microbiome before and during pregnancy and its impact on reproductive health will greatly promote maternal and fetal health. Such knowledge can also contribute to the development of ARTs and microbiome-based interventions.

Vertical transmission of microbiomes into embryo culture media and its association with assisted reproductive outcomes

RESEARCH QUESTION

Can microbes vertically transmit from semen and follicular fluid to embryo culture media during assisted reproductive technology (ART) treatment?

DESIGN

Spent embryo culture media (SECM), seminal fluid and follicular fluid samples were collected from 61 couples with infertility undergoing ART treatment at the Prince of Wales Hospital, Hong Kong SAR, China. Metagenomic analysis was conducted using 16s rRNA sequencing to identify the source of microbes in SECM, correlation between the semen microbiome and male infertility, and correlation between the follicular fluid microbiome and female infertility.

RESULTS

Microbial vertical transmission into SECM was reported in 82.5% of cases, and semen was the main source of contamination in conventional IVF cases. The increased abundances of Staphylococcus spp. and Streptococcus anginosus in semen had negative impacts on total motility and sperm count, respectively (P < 0.001). Significant increases in abundance of the genera Prophyromonas, Neisseria and Facklamia were observed in follicular fluid in women with anovulation, uterine factor infertility and unexplained infertility, respectively (P < 0.01). No significant correlation was found between the bacteria identified in all sample types and ART outcomes, including fertilization rate, embryo development, number of available embryos, and clinical pregnancy rate.

CONCLUSION

Embryo culture media can be contaminated during ART treatment, not only by seminal microbes but also by follicular fluid and other sources of microbes. Strong correlations were found between specific microbial taxa in semen and sperm quality, and between the follicular fluid microbiome and the aetiology of female infertility. However, no significant association was found between the microbiomes of SECM, semen and follicular fluid and ART outcomes.

The effect of the female genital tract and gut microbiome on reproductive dysfunction

Microorganisms are ubiquitous in the human body; they are present in various areas including the gut, mouth, skin, respiratory tract, and reproductive tract. The interaction between the microbiome and reproductive health has become an increasingly compelling area of study. Disruption of the female genital tract microbiome can significantly impact the metabolism of amino acids, carbohydrates, and lipids, increasing susceptibility to reproductive tract diseases such as vaginitis, chronic endometritis, endometrial polyps, endometriosis, and polycystic ovary syndrome. The gut microbiome, considered an endocrine organ, plays a crucial role in the reproductive endocrine system by interacting with hormones like estrogen and androgens. Imbalances in the gut microbiome composition can lead to various diseases and conditions, including polycystic ovary syndrome, endometriosis, and cancer, although research on their mechanisms remains limited. This review highlights the latest advancements in understanding the female genital tract and gut microbiomes in gynecological diseases. It also explores the potential of microbial communities in the treatment of reproductive diseases. Future research should focus on identifying the molecular mechanisms underlying the association between the microbiome and reproductive diseases to develop new and effective strategies for disease prevention, diagnosis, and treatment related to female reproductive organs.

Associations between microbial presence in follicular fluid with IVF outcomes: a systematic review and meta-analysis

PURPOSE

The aim of the study was to synthesize disparate studies to investigate potential impact of microbial presence in FF of infertile women on IVF outcomes.

METHODS

Following preliminary searches to find medical subject heading (MeSH) terms plus free terms, a systematic search was performed in the PubMed, Cochrane Library, Embase, Web of Science, and Clinicaltrials.gov databases from January 10, 2022, to July 5, 2023. Data collected for each study were analyzed using RevMan 5.4 software available on the Cochrane website.

RESULTS

After correcting for contamination from the vagina, the FFs of 289 women were detected positively by microbial culture and identification, ELISA, and IPA. The pregnancy rate of the FF-positive group was significantly lower than the FF-negative group (19.7% vs. 32.2%) and (OR: 0.57, 95% CI: 0.28-1.14, P=0.11; I2=56%) while the fertilization rate was almost equal (60.0% vs. 62.0%) and (OR: 1.03, 95% CI: 0.88-1.20, P=0.72; I2=0%). Evidence quality was very low.

CONCLUSIONS

The different species of microorganisms in FF of infertile women may have different effects on IVF outcomes. The Lactobacillus spp. may have a positive effect, while other microorganisms may have the opposite effect.

The relationship between microbial contaminations of embryo transfer catheters with pregnancy outcome after embryo transfer

Background

Different stages of assisted reproductive technologies are susceptible to contamination by various microorganisms.

Objective

The aim of the study was to investigate the relationship between microbial contamination of embryo transfer catheters and the pregnancy outcome after embryo transfer.

Methods

This cohort study was conducted on 60 patients candied for in vitro fertilization and embryo transfer cycles from 2021 to 2022. All embryos were transferred using a sterile syringe. The catheter contamination was checked by the microbial culture method, and in the case of microbial culture that were negative, polymerase chain reaction was done to confirm the result. The data analyzed using STATA 17 to determine the impact of catheter contamination on the clinical pregnancy rate.

Results

The average age of peoples whose microbial culture was positive was lower than that of people whose microbial culture was negative (P<0.05). Also the results showed that people who live in villages have more positive microbial cultures than people who live in cities (P<0.05). Also there is no difference between the number of successful implantations and the pregnancy outcome between people whose microbial culture results were positive or negative.

Conclusion

The results of the current study showed that the contamination of the embryo transfer catheter with microorganisms under our investigation did not affect the pregnancy outcome.

Characterization of the follicular fluid microbiota based on culturomics and sequencing analysis

Introduction. The human oocyte microenvironment is follicular fluid, which is important for follicle growth, ovulation and maturation of the oocyte. The micro-organisms present in follicular fluid could be a predictor of in vitro fertilization outcomes.Hypothesis/Gap Statement. Women with follicular fluid colonized with micro-organisms can be asymptomatic, but the presence of some genera in the follicular fluid correlates with in vitro fertilization.Aim. To confirm the existence of micro-organisms in follicular fluid, and to profile the micro-organisms present in follicular fluid sampled from women undergoing in vitro fertilization with different outcomes.Methodology. Women undergoing in vitro fertilization (n=163) were divided into different subgroups according to their in vitro fertilization outcomes. Their follicular fluid samples were collected, and among them, 157 samples were analysed by 16S rDNA sequencing, and 19 samples were analysed using culturomics.Results. The culturomics results suggested that the 19 follicular fluid samples were not sterile. The isolation rates for Streptococcus, Finegoldia and Peptoniphilus were >50 % in the 19 samples. Linear discriminant analysis effect size analysis showed differential bacteria abundance according to the pregnancy rate, the rate of normal fertilization, the rate of high-quality embryos and the rate of available oocytes. The sequencing results showed that micro-organisms could be detected in all 157 samples. Pseudomonas, Lactobacillus, Comamonas, Streptococcus and Acinetobacter were detected in all of the samples, but with a wide range of relative abundance. Pseudomonas, Lactobacillus, Ralstonia and Vibrio constituted a notable fraction of the microbiota.Conclusions. Follicular fluid is not sterile. Micro-organisms in follicular fluid could be a predictor of in vitro fertilization outcomes.

An Overview of the Microbiota of the Human Urinary Tract in Health and Disease: Current Issues and Perspectives

This article is intended to deepen our knowledge to date regarding the functions of the resident microbiota/microbiome in the urinary system for human health and disease. First, we sought to report the general characteristics (composition and stability) of the normal urinary system microbiota in the different anatomical sites in relation to some factors such as the effect of age, gender and diet, analyzing in detail the functions and the composition of the microbiota in the light of current knowledge. Several pieces of evidence suggest the importance of preserving the micro-ecosystem of the urinary system, and in some cases their relationship with diseases is important for maintaining human health is well understood. The female and male reproductive microbiota have mainly been studied over the past decade. In the past, the arrest was thought to have taken place in a sterile environment. Microorganisms of the microbiota form biofilms, three-dimensional structures, that differ in the reproductive organs and interact with both gametes and the embryo as well as with maternal tissues. These biofilms from the reproductive system also interact with others, such as that of the gastrointestinal tract. Reduction in its diversity intestinal microbiota can disrupt estrogen metabolism and affect the reproductive microbiota. It is therefore understood that its quantitative and qualitative identification is important for microbiota, but also the study of the structures formed by the microorganisms. A dysbiosis with local or systemic causes can lead to serious diseases. The role of probiotics in maintaining microbial population harmony (eubiosis) and preventing certain pathologies of the urinary and reproductive system was also investigated. A negative variation in the qualitative and quantitative composition of certain strains of microorganisms (dysbiosis) due to local or systemic causes can even lead to serious diseases. The role of probiotics in maintaining the healthy balance of microorganism populations (eubiosis), and thus in the prevention of certain pathologies of the urinary and reproductive system, has also been studied.

Microbiological composition of follicular fluid in patients undergoing IVF and its association with infertility

PROBLEM

In recent years, the incidence of female infertility has risen sharply, which is affected by many factors. It was recognized that female reproductive tract microbes play a role in the process of female conception. If the reproductive tract microbes could solve a certain proportion of infertility, it would certainly reduce the pain and economic burden of many patients. The objective of this study was to investigate the microbial community composition of follicular fluid in infertile patients and its potential impact on infertility.

METHOD OF STUDY

Follicular fluid from 49 primary infertility and 52 secondary infertility patients was collected by a negative pressure needle, and the microbiota was analyzed by 16S rDNA sequencing.

RESULTS

It was found that Lactobacillus, especially L. crispatus, might have a positive effect on female pregnancy. Considering the presence or absence of male factors and different body mass indices, L. iners might inhibit female pregnancy. However, L. iners seemed to play a positive role in egg maturation, while Gardnerella and Cutibacterium acnes might have a negative effect on female pregnancy.

CONCLUSIONS

This study suggested the potential role of Lactobacillus in follicular fluid in improving female infertility and provided a theoretical basis for the future microbiological treatment of female infertility.

Urogenital tract and rectal microbiota composition and its influence on reproductive outcomes in infertile patients

Introduction

Microbiota in the human body are closely related to human diseases. Female urogenital tract and rectal microbes have been considered as important factors affecting female pregnancy, but the mechanism is unknown.

Methods

Cervical, vaginal, urethral, and rectal swabs were collected from 22 infertile patients and 10 controls, and follicular fluid was extracted from 22 infertile patients. The microbial composition of different sampling sites of infertile patients was examined. By comparing the microbial composition difference between infertile patients and controls and combining bioinformatics methods to analyze the potential impact of the female urogenital tract (cervical, vaginal and urethral) and rectal microbial diversity on female infertility and pregnancy outcomes.

Results

Lactobacillus predominated in the female urogenital tract, but its abundance decreased in infertile patients, whereas the abundance of Gardnerella and Atopobium increased. The microbial changes in the urethra had the same trend as that in the vagina. Compared with healthy controls, the cervical and rectal microbial diversity of infertile patients were significantly increased and decreased, respectively. There might be interactions between microbes in different parts of female. Geobacillus thermogeniticans was enriched in the urogenital tract and rectum of infertile patients, and has a good predictive effect on infertility. Compared with infertile patients, L. johnsonii was enriched in the vagina, urethra, and intestine of the control group. L. acidophilus in follicular fluid might be associated with Non-pregnancy.

Conclusion

This study found that the microbial composition of infertile patients was changed compared with that of healthy people. The translocation of Lactobacillus between the rectum and urogenital tract might play a protective barrier role. The changes of Lactobacillus and Geobacillus might be related to female infertility or pregnancy outcome. The study provided a theoretical basis for the future treatment of female infertility from the perspective of microorganisms by detecting the microbial changes associated with female infertility.

Unveiling Key Biomarkers and Therapeutic Drugs in Polycystic Ovary Syndrome (PCOS) Through Pathway Enrichment Analysis and Hub Gene-miRNA Networks

Background

Polycystic ovary syndrome (PCOS) affects women of reproductive age globally with an incidence rate of 5% - 26%. Growing evidence reports important roles for microRNAs (miRNAs) in the pathophysiology of granulosa cells (GCs) in PCOS.

Objectives

The objectives of this study were to identify the top differentially expressed miRNAs (DE-miRNAs) and their corresponding targets in hub gene-miRNA networks, as well as identify novel DE-miRNAs by analyzing three distinct microarray datasets. Additionally, functional enrichment analysis was performed using bioinformatics approaches. Finally, interactions between the 5 top-ranked hub genes and drugs were investigated.

Methods

Using bioinformatics approaches, three GC profiles from the gene expression omnibus (GEO), namely gene expression omnibus series (GSE)-34526, GSE114419, and GSE137684, were analyzed. Targets of the top DE-miRNAs were predicted using the multiMiR R package, and only miRNAs with validated results were retrieved. Genes that were common between the "DE-miRNA prediction results" and the "existing tissue DE-mRNAs" were designated as differentially expressed genes (DEGs). Gene ontology (GO) and pathway enrichment analyses were implemented for DEGs. In order to identify hub genes and hub DE-miRNAs, the protein-protein interaction (PPI) network and miRNA-mRNA interaction network were constructed using Cytoscape software. The drug-gene interaction database (DGIdb) database was utilized to identify interactions between the top-ranked hub genes and drugs.

Results

Out of the top 20 DE-miRNAs that were retrieved from the GSE114419 and GSE34526 microarray datasets, only 13 of them had "validated results" through the multiMiR prediction method. Among the 13 DE-miRNAs investigated, only 5, namely hsa-miR-8085, hsa-miR-548w, hsa-miR-612, hsa-miR-1470, and hsa-miR-644a, demonstrated interactions with the 10 hub genes in the hub gene-miRNA networks in our study. Except for hsa-miR-612, the other 4 DE-miRNAs, including hsa-miR-8085, hsa-miR-548w, hsa-miR-1470, and hsa-miR-644a, are novel and had not been reported in PCOS pathogenesis before. Also, GO and pathway enrichment analyses identified "pathogenic E. coli infection" in the Kyoto encyclopedia of genes and genomes (KEGG) and "regulation of Rac1 activity" in FunRich as the top pathways. The drug-hub gene interaction network identified ACTB, JUN, PTEN, KRAS, and MAPK1 as potential targets to treat PCOS with therapeutic drugs.

Conclusions

The findings from this study might assist researchers in uncovering new biomarkers and potential therapeutic drug targets in PCOS treatment.

Microbiota of female genital tract – functional overview of microbial flora from vagina to uterine tubes and placenta

Microorganisms and eukaryotic human cells coexist in synergistic relationships in nearly every niche of the human body. The female genital tract consisting of the vagina, uterus with its cervix and endometrium, uterine tubes and ovaries – harbors its own typical microbiota, which accounts for 9 % of the total bacterial population in females. To this organ system, we also assigned the microbiome of the placenta, which has not been studied much until now. Among the spectrum of microbial species, the female genital tract is mainly dominated by Lactobacillus species, which are considered to be one of the simplest yet most important microbial communities. However, this relationship between macro- and micro-organisms seems to have a number of physiological functions, e.g., the vaginal and cervical microbiota have unique impact on reproductive health. The aim of this review was to provide current view on female genital tract microbiota and its role in reproductive health. We describe in detail the association of vaginal or tubal epithelium with microbiota or the role of microbiota in normal placental function.

Gut and genital tract microbiomes: Dysbiosis and link to gynecological disorders

Every year, millions of women are affected by genital tract disorders, such as bacterial vaginosis (BV), endometrial cancer, polycystic ovary syndrome (PCOS), endometriosis, and uterine fibroids (UFs). These disorders pose a significant economic burden on healthcare systems and have serious implications for health and fertility outcomes. This review explores the relationships between gut, vaginal, and uterine dysbiosis and the pathogenesis of various diseases of the female genital tract. In recent years, reproductive health clinicians and scientists have focused on the microbiome to investigate its role in the pathogenesis and prevention of such diseases. Recent studies of the gut, vaginal, and uterine microbiomes have identified patterns in bacterial composition and changes across individuals' lives associated with specific healthy and diseased states, particularly regarding the effects of the estrogen-gut microbiome axis on estrogen-driven disorders (such as endometrial cancer, endometriosis, and UFs) and disorders associated with estrogen deficiency (such as PCOS). Furthermore, this review discusses the contribution of vitamin D deficiency to gut dysbiosis and altered estrogen metabolism as well as how these changes play key roles in the pathogenesis of UFs. More research on the microbiome influences on reproductive health and fertility is vital.

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.

Microbiology of Human Follicular Fluid and the Vagina and Its Impact on in Vitro Fertilization Outcomes

PURPOSE

The present study aimed to identify microorganisms in follicular fluids and to investigate their association with in vitro fertilization (IVF) outcomes.

MATERIALS AND METHODS

This study was conducted as a prospective study of 49 infertile females undergoing IVF/intracytoplasmic sperm injection cycles between 2013 and 2016. Paired follicular fluid and vaginal secretions were collected on the day of ovum pick up and were cultured to detect microorganisms.

RESULTS

Fifteen women (30.6%) had no microorganisms in follicular fluid or vaginal swabs, 23 (46.9%) had microorganisms on vaginal swab alone, 3 (6.1%) had microorganisms in follicular fluid alone, and 8 (16.3%) had microorganisms in both follicular fluid and vaginal swabs. The same microorganisms were detected in both the follicular fluid and vaginal swabs of three women, while different microorganisms were detected between follicular fluid and vaginal swabs in five women. Follicular fluid microorganisms were not associated with embryo quality or clinical pregnancy rates during IVF cycles. However, significantly decreased implantation rates (9.1% vs. 29.4%, p=0.031) and clinical pregnancy rates on embryo transfer day 5 (0% vs. 83.3%, p=0.048) were observed in the group that was positive for vaginal pathogens.

CONCLUSION

Follicular fluid contains microorganisms that can differ from those in the vagina of the same women; however, they do not appear to be associated with embryo quality or clinical pregnancy rates in IVF cycles. In contrast, vaginal pathogens were found to be associated with worse implantation rates and clinical pregnancy rates in IVF cycles.

Ligilactobacillus salivarius PS11610 exerts an effect on the microbial and immunological profile of couples suffering unknown infertility

PROBLEM

Unknown or idiopathic infertility has been associated with urogenital tract dysbiosis, reducing pregnancy and delivery ratios during assisted reproductive treatments (ART). The Ligilactobacillus salivarius PS11610 strain has shown extraordinary antimicrobial activity in vitro against urogenital pathogens as well as other probiotic characteristics. Therefore, an intervention study was performed to evaluate the effect of L. salivarius PS11610 on the microbial composition of urogenital tract in infertile couples with bacterial dysbiosis.

METHOD OF STUDY

Seventeen couples undergoing ART diagnosed with unknown infertility were selected. After confirming urogenital dysbiosis, they started a 6-month treatment with L. salivarius PS11610 (1 dose/12 h for female and 1 dose/24 h for male). Vaginal, seminal, glans, uterine and plasma samples were collected for determination of the microbiome and immune profile at the beginning and the end of the treatment.

RESULTS

Supplementation with L. salivarius PS11610 significantly modified the urogenital microbiome composition in male and female samples, solving dysbiosis of 67% of the couples. Pathogens disappeared from the vaginal samples whereas Lactobacilli percentage increased after 3 and 6 months of treatment. Moreover, L. salivarius PS11610 changed the uterine microbiome that could be associated with a change of the uterine immune profile. Additionally, the probiotic intake could be associated with the observed change in the systemic immunological profile of couples. Finally, the pregnant and delivery ratio were improved.

CONCLUSIONS

Probiotic supplementation with L. salivarius PS11610 improved the male and female urogenital tract microbiome, modulating the immune system and increasing pregnancy success in couples undergoing ART.

Microorganisms in the reproductive system and probiotic's regulatory effects on reproductive health

The presence of microbial communities in the reproductive tract has been revealed, and this resident microbiota is involved in the maintenance of health. Intentional modulation via probiotics has been proposed as a possible strategy to enhance reproductive health and reduce the risk of diseases. The male seminal microbiota has been suggested as an important factor that influences a couple’s health, pregnancy outcomes, and offspring health. Probiotics have been reported to play a role in male fertility and to affect the health of mothers and offspring. While the female reproductive microbiota is more complicated and has been identified in both the upper and lower reproductive systems, they together contribute to health maintenance. Probiotics have shown regulatory effects on the female reproductive tract, thereby contributing to homeostasis of the tract and influencing the health of offspring. Further, through transmission of bacteria or through other indirect mechanisms, the parent’s reproductive microbiota and probiotic intervention influence infant gut colonization and immunity development, with potential health consequences. In vitro and in vivo studies have explored the mechanisms underlying the benefits of probiotic administration and intervention, and an array of positive results, such as modulation of microbiota composition, regulation of metabolism, promotion of the epithelial barrier, and improvement of immune function, have been observed. Herein, we review the state of the art in reproductive system microbiota and its role in health and reproduction, as well as the beneficial effects of probiotics on reproductive health and their contributions to the prevention of associated diseases.

The search for aliens within us: a review of evidence and theory regarding the foetal microbiome

The microbiome is believed to be established during the birthing process through exposure to the maternal microbiome and immediate external environment. The absence of a microbiome prior to birth is based on the sterile womb hypothesis, which was formulated at the beginning of the 20th century and is supported primarily by the culture-based approach in microbiological studies.Findings of bacterial presence in products of fertilization such as the placenta, amniotic fluid, foetal membranes, and umbilical cord blood in studies using next-generation DNA sequencing technologies began to challenge the sterile nature of the intrauterine environment during gestation. These studies have been mainly criticized by their approach to contamination and inconclusive evidence of viability. The implications of bacterial presence in utero are far reaching in medicine and basic sciences. If commensal bacteria exist in the foetus, antibiotic therapies in pregnancy particularly for asymptomatic cases will need to be re-evaluated. Experimental studies utilizing gnotobiology may also be impacted by a realignment of theory.This review of existing literature aims to provide insight into the existence of bacteria in utero, specifically the foetal microbiome through analysis of experimental evidence and theoretical concepts, and to suggest approaches that may further provide clarity into this inquiry.

The role of gut and genital microbiota and the estrobolome in endometriosis, infertility and chronic pelvic pain

BACKGROUND

Endometriosis is a chronic, burdensome condition that is historically understudied. Consequently, there is a lack of understanding of the etiology of the disease and its associated symptoms, including infertility and chronic pelvic pain (CPP). Endometriosis development is influenced by estrogen metabolism and inflammation, which are modulated by several factors including the microbiome and the estrobolome (the collection of genes encoding estrogen-metabolizing enzymes in the gut microbiome). Therefore, there is increasing interest in understanding the role of microbiota in endometriosis etiology.

OBJECTIVE AND RATIONALE

To date, there is no cure for endometriosis and treatment options often are ineffective. This manuscript will review the potential relationship between the microbiome and endometriosis, infertility and CPP and highlight the available data on the microbiome in relation to endometriosis and its related symptoms. The overarching goal of this manuscript is to inform future microbiome research that will lead to a deeper understanding of the etiology of the disease and possible diagnostic modalities and treatments. The potential impact of the microbiome on estrogen regulation modulated by the estrobolome, as well as inflammation and other endometriosis-promoting mechanisms within the genital tract, will be reviewed. The methodological limitations of microbiome-related studies will be critically assessed to provide improved guidelines for future microbiome and clinical studies.

SEARCH METHODS

PubMed databases were searched using the following keywords: endometriosis AND microbiome, infertility AND microbiome, pelvic pain AND microbiome, IVF (in-vitro fertilization) AND microbiome, endometriosis AND infertility. Clinical and preclinical animal trials that were eligible for review, and related to microbiome and endometriosis, infertility or CPP were included. All available manuscripts were published in 2002-2021.

OUTCOMES

In total, 28 clinical and 6 animal studies were included in the review. In both human and animal studies, bacteria were enriched in endometriosis groups, although there was no clear consensus on specific microbiota compositions that were associated with endometriosis, and no studies included infertility or CPP with endometriosis. However, bacterial vaginosis-associated bacteria and Lactobacillus depletion in the cervicovaginal microbiome were associated with endometriosis and infertility in the majority (23/28) of studies. Interpretation of endometrial studies is limited owing to a variety of methodological factors, discussed in this review. In addition, metadata outlining antibiotic usage, age, race/ethnicity, menopausal status and timing of sample collection in relation to diagnosis of endometriosis was not consistently reported. Animal studies (6/6) support a bidirectional relationship between the gut microbiota and endometriosis onset and progression.

WIDER IMPLICATIONS

There is evidence that a dysbiotic gut or genital microbiota is associated with multiple gynecologic conditions, with mounting data supporting an association between the microbiome and endometriosis and infertility. These microbiomes likely play a role in the gut-brain axis, which further supports a putative association with the spectrum of symptoms associated with endometriosis, including infertility and CPP. Collectively, this review highlights the demand for more rigorous and transparent methodology and controls, consistency across the field, and inclusion of key demographic and clinical characteristics of disease and comparison participants. Rigorous study designs will allow for a better understanding of the potential role of the microbiome in endometriosis etiology and the relationship to other disorders of the female reproductive tract.

The impact of the female genital tract microbiome in women health and reproduction: a review

PURPOSE

The aim of this review is to gather the available research focusing on female genital tract (FGT) microbiome. Research question focuses in decipher which is the role of FGT microbiota in eubiosis, assisted reproduction techniques (ARTs), and gynaecological disorders, and how microbiome could be utilised to improve reproduction outcomes and to treat fertility issues.

METHODS

PubMed was searched for articles in English from January 2004 to April 2021 for "genital tract microbiota and reproduction", "endometrial microbiome", "microbiome and reproduction" and "microbiota and infertility". Manual search of the references within the resulting articles was performed.

RESULTS

Current knowledge confirms predominance of Lactobacillus species, both in vagina and endometrium, whereas higher variability of species is both found in fallopian tubes and ovaries. Microbial signature linked to different disorders such endometriosis, bacterial vaginosis, and gynaecological cancers are described. Broadly, low variability of species and Lactobacillus abundance within the FGT is associated with better reproductive and ART outcomes.

CONCLUSION

Further research regarding FGT microbiome configuration needs to be done in order to establish a more precise link between microbiota and eubiosis or dysbiosis. Detection of bacterial species related with poor reproductive outcomes, infertility or gynaecological diseases could shape new tools for their diagnosis and treatment, as well as resources to assess the pregnancy prognosis based on endometrial microbiota. Data available suggest future research protocols should be standardised, and it needs to include the interplay among microbiome, virome and mycobiome, and the effect of antibiotics or probiotics on the microbiome shifts.

To understand the reproductive tract microbiome associated with infertility through metagenomics analysis

Background

Knowledge of the microbiome is in its infancy in health and human illness, especially concerning human reproduction. We will be better able to treat dysbiosis of the reproductive tract clinically if it is better explained and understood. It has been shown that altered vaginal microbiota affects parturition, and its function is uncertain in assisted reproductive technologies. However, the effects of recognized microbes such as Mycoplasma tuberculosis, Chlamydia trachomatis, and Neisseria gonorrhoeae are well established, resulting in subclinical changes which are considered to be risk factors for infertility and poor reproductive outcomes.

Main body

Recent studies indicate that the vaginal tract comprises several different organisms of the microbiome. Some microbiota can play an important role not only in the reproductive tract but also in overall health. The microbiome of the female reproductive tract has been identified mainly based on studies that examine vaginal samples across many reproductive technologies, using a metagenomics approach.

Conclusion

Alteration of reproductive tract microbiota or presence of certain microbiota irrespective of the level of pathogenicity may interfere with fertilization, implantation, and subsequent embryo development. This may lead to failed fertility treatments and reduced live birth rate (LBR).

The presence of microorganisms in follicular fluid and its effect on the outcome of in vitro fertilization-embryo transfer (IVF-ET) treatment cycles

Objectives

To determine if the presence of microorganisms in follicular fluid of women undergoing in vitro fertilization-embryo transfer (IVF-ET) adversely affects the outcome of the treatment cycles.

Methods

Follicular fluid was collected from 86 women enrolled for IVF-ET at the National Hospital, Abuja from June 1, 2018 to December 1, 2018. Microscopy imaging and cultures were performed to identify bacteria and fungi in the follicular fluid and the vagina. Women with follicular fluid microorganisms were the test group while the controls were those without follicular fluid microorganisms. Fertilization and pregnancy rates were subsequently determined and their association with the presence of follicular fluid microorganisms was assessed using univariable and multivariable logistic regression modelling.

Results

The mean age and mean Body Mass Index (BMI) of the participants were 35(± 3.5) years and 28(± 4.9) kg/m² respectively. Bacteria and fungi were isolated in 17% of the follicular fluid samples collected (n = 15/86). Most common isolates were Streptococcus spp. (n = 4/15), Staphylococcus aureus (n = 7/15), Enterococcus spp. (n = 4/15), Lactobacillus species (n = 2/15) and Candida albicans (n = 2/15). There was no statistically significant difference in the fertilization rates (adjusted odds ratio [AdjOR] 0.55, 95% confidence interval [CI] 0.04–7.34; P = 0.10) and pregnancy rates (AdjOR 4.02, 95% CI 0.56–28.92; P = 0.19) between the group of women with positive follicular fluid bacterial /fungal colonization as compared against those with negative follicular fluid colonization.

Conclusion

Isolation of microorganisms from follicular fluid did not adversely affect fertilization and pregnancy rates following IVF-ET treatment cycles at the fertility centre of National Hospital, Abuja.

Lactobacillus iners and gasseri, Prevotella bivia and HPV Belong to the Microbiological Signature Negatively Affecting Human Reproduction

Infertile couples undergoing the use of assisted reproductive technology are a good study model to evaluate the microbiological signatures affecting reproductive health. We tested vaginal lavages, follicular fluids, embryo culture mediums, and seminal fluids from 47 couples for their microbiome composition and HPV infection. Twenty-five infertile couples were diagnosed with unexplained infertility, whereas 22 were diagnosed with explained infertility. Lactobacilli were dominant in the vaginal lavages of both patient groups, and the most abundant species was L. iners (CST III), which is linked to a decreased fertility rate. Besides this, L. gasseri—which is known to be associated with oocyte DNA fragmentation and decreased sperm mobility—was identified in the seminal fluids, follicular fluids, and embryo culture media of the unexplained infertility group. Prevotella was increased in the seminal fluids of the explained infertility group, along with HPV-positive seminal fluids: an infection commonly associated with infertility, especially male infertility. Prevotella has been described to negatively affect sperm motility. Taken together, these results suggest that the profiling of the reproductive tract microbiome can add new perspectives to human reproduction.

The vaginal microbiome as a predictor for outcome of in vitro fertilization with or without intracytoplasmic sperm injection: a prospective study

STUDY QUESTION

Is the presence or absence of certain vaginal bacteria associated with failure or success to become pregnant after an in vitro fertilization (IVF) or IVF with intracytoplasmic sperm injection (IVF-ICSI) treatment?

SUMMARY ANSWER

Microbiome profiling with the use of interspace profiling (IS-pro) technique enables stratification of the chance of becoming pregnant prior to the start of an IVF or IVF-ICSI treatment.

WHAT IS KNOWN ALREADY

Live-birth rates for an IVF or IVF-ICSI treatment vary between 25 and 35% per cycle and it is difficult to predict who will or will not get pregnant after embryo transfer (ET). Recently, it was suggested that the composition of the vaginal microbiota prior to treatment might predict pregnancy outcome. Analysis of the vaginal microbiome prior to treatment might, therefore, offer an opportunity to improve the success rate of IVF or IVF-ICSI.

STUDY DESIGN, SIZE, DURATION

In a prospective cohort study, 303 women (age, 20-42 years) undergoing IVF or IVF-ICSI treatment in the Netherlands were included between June 2015 and March 2016.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Study subjects provided a vaginal sample before the start of the IVF or IVF-ICSI procedure. The vaginal microbiota composition was determined using the IS-pro technique. IS-pro is a eubacterial technique based on the detection and categorization of the length of the 16S-23S rRNA gene interspace region. Microbiome profiles were assigned to community state types based on the dominant bacterial species. The predictive accuracy of the microbiome profiles for IVF and IVF-ICSI outcome of fresh ET was evaluated by a combined prediction model based on a small number of bacterial species. From this cohort, a model was built to predict outcome of fertility treatment. This model was externally validated in a cohort of 50 women who were undergoing IVF or IVF-ICSI treatment between March 2018 and May 2018 in the Dutch division of the MVZ VivaNeo Kinderwunschzentrum Düsseldorf, Germany.

MAIN RESULTS AND THE ROLE OF CHANCE

In total, the vaginal microbiota of 192 women who underwent a fresh ET could be analysed. Women with a low percentage of Lactobacillus in their vaginal sample were less likely to have a successful embryo implantation. The prediction model identified a subgroup of women (17.7%, n = 34) who had a low chance to become pregnant following fresh ET. This failure was correctly predicted in 32 out of 34 women based on the vaginal microbiota composition, resulting in a predictive accuracy of 94% (sensitivity, 26%; specificity, 97%). Additionally, the degree of dominance of Lactobacillus crispatus was an important factor in predicting pregnancy. Women who had a favourable profile as well as <60% L. crispatus had a high chance of pregnancy: more than half of these women (50 out of 95) became pregnant. In the external validation cohort, none of the women who had a negative prediction (low chance of pregnancy) became pregnant.

LIMITATIONS, REASONS FOR CAUTION

Because our study uses a well-defined study population, the results will be limited to the IVF or IVF-ICSI population. Whether these results can be extrapolated to the general population trying to achieve pregnancy without ART cannot be determined from these data.

WIDER IMPLICATIONS OF THE FINDINGS

Our results indicate that vaginal microbiome profiling using the IS-pro technique enables stratification of the chance of becoming pregnant prior to the start of an IVF or IVF-ICSI treatment. Knowledge of their vaginal microbiota may enable couples to make a more balanced decision regarding timing and continuation of their IVF or IVF-ICSI treatment cycles.

STUDY FUNDING/COMPETING INTEREST(S)

This study was financed by NGI Pre-Seed 2014-2016, RedMedTech Discovery Fund 2014-2017, STW Valorisation grant 1 2014-2015, STW Take-off early phase trajectory 2015-2016 and Eurostars VALBIOME grant (reference number: 8884). The employer of W.J.S.S.C. has in collaboration with ARTPred acquired a MIND subsidy to cover part of the costs of this collaboration project. The following grants are received but not used to finance this study: grants from Innovatie Prestatie Contract, MIT Haalbaarheid, other from Dutch R&D tax credit WBSO, RedMedTech Discovery Fund, (J.D.d.J.). Grants from Ferring (J.S.E.L., K.F., C.B.L. and J.M.J.S.S.), Merck Serono (K.F. and C.B.L.), Dutch Heart Foundation (J.S.E.L.), Metagenics Inc. (J.S.E.L.), GoodLife (K.F.), Guerbet (C.B.L.). R.K. is employed by ARTPred B.V. during her PhD at Erasmus Medical Centre (MC). S.A.M. has a 100% University appointment. I.S.P.H.M.S., S.A.M. and A.E.B. are co-owners of IS-Diagnostics Ltd. J.D.d.J. is co-owner of ARTPred B.V., from which he reports personal fees. P.H.M.S. reports non-financial support from ARTPred B.V. P.H.M.S., J.D.d.J. and A.E.B. have obtained patents `Microbial population analysis' (9506109) and `Microbial population analysis' (20170159108), both licenced to ARTPred B.V. J.D.d.J. and A.E.B. report patent applications `Method and kit for predicting the outcome of an assisted reproductive technology procedure' (392EPP0) and patent `Method and kit for altering the outcome of an assisted reproductive technology procedure' by ARTPred. W.J.S.S.C. received personal consultancy and educational fees from Goodlife Fertility B.V. J.S.E.L. reports personal consultancy fees from ARTPred B.V., Titus Health B.V., Danone, Euroscreen and Roche during the conduct of the study. J.S.E.L. and N.G.M.B. are co-applicants on an Erasmus MC patent (New method and kit for prediction success of in vitro fertilization) licenced to ARTPred B.V. F.J.M.B. reports personal fees from Advisory Board Ferring, Advisory Board Merck Serono, Advisory Board Gedeon Richter and personal fees from Educational activities for Ferring, outside the submitted work. K.F. reports personal fees from Ferring (commercial sponsor) and personal fees from GoodLife (commercial sponsor). C.B.L. received speakers' fee from Ferring. J.M.J.S.S. reports personal fees and other from Merck Serono and personal fees from Ferring, unrelated to the submitted paper. The other authors declare that they have no competing interests.

TRIAL REGISTRATION NUMBER

ISRCTN83157250. Registered 17 August 2018. Retrospectively registered.

Identification and evaluation of the microbiome in the female and male reproductive tracts

BACKGROUND

The existence of an extensive microbiome in and on the human body has increasingly dominated the scientific literature during the last decade. A shift from culture-dependent to culture-independent identification of microbes has occurred since the emergence of next-generation sequencing (NGS) techniques, whole genome shotgun and metagenomic sequencing. These sequencing analyses have revealed the presence of a rich diversity of microbes in most exposed surfaces of the human body, such as throughout the reproductive tract. The results of microbiota analyses are influenced by the technical specifications of the applied methods of analyses. Therefore, it is difficult to correctly compare and interpret the results of different studies of the same anatomical niche.

OBJECTIVES AND RATIONALE

The aim of this narrative review is to provide an overview of the currently used techniques and the reported microbiota compositions in the different anatomical parts of the female and male reproductive tracts since the introduction of NGS in 2005. This is crucial to understand and determine the interactions and roles of the different microbes necessary for successful reproduction.

SEARCH METHODS

A search in Embase, Medline Ovid, Web of science, Cochrane and Google scholar was conducted. The search was limited to English language and studies published between January 2005 and April 2018. Included articles needed to be original microbiome research related to the reproductive tracts.

OUTCOMES

The review provides an extensive up-to-date overview of current microbiome research in the field of human reproductive medicine. The possibility of drawing general conclusions is limited due to diversity in the execution of analytical steps in microbiome research, such as local protocols, sampling methods, primers used, sequencing techniques and bioinformatic pipelines, making it difficult to compare and interpret results of the available studies. Although some microbiota are associated with reproductive success and a good pregnancy outcome, it is still unknown whether a causal link exists. More research is needed to further explore the possible clinical implications and therapeutic interventions.

WIDER IMPLICATIONS

For the field of reproductive medicine, determination of what is a favourable reproductive tract microbiome will provide insight into the mechanisms of both unsuccessful and successful human reproduction. To increase pregnancy chances with live birth and to reduce reproduction-related health costs, future research could focus on postponing treatment or conception in case of the presence of unfavourable microbiota and on the development of therapeutic interventions, such as microbial therapeutics and lifestyle adaptations.

The complex microbiome from native semen to embryo culture environment in human in vitro fertilization procedure

BACKGROUND

Only a few microbial studies have conducted in IVF (in vitro fertilization), showing the high-variety bacterial contamination of IVF culture media to cause damage to or even loss of cultured oocytes and embryos. We aimed to determine the prevalence and counts of bacteria in IVF samples, and to associate them with clinical outcome.

METHODS

The studied samples from 50 infertile couples included: raw (n = 48), processed (n = 49) and incubated (n = 50) sperm samples, and IVF culture media (n = 50). The full microbiome was analyzed by 454 pyrosequencing and quantitative analysis by real-time quantitative PCR. Descriptive statistics, t-, Mann-Whitney tests and Spearman's correlation were used for comparison of studied groups.

RESULTS

The study involved normozoospermic men. Normal vaginal microbiota was present in 72.0% of female partners, while intermediate microbiota and bacterial vaginosis were diagnosed in 12.0 and 16.0%, respectively. The decreasing bacterial loads were found in raw (35.5%), processed (12.0%) and sperm samples used for oocyte insemination (4.0%), and in 8.0% of IVF culture media. The most abundant genera of bacteria in native semen and IVF culture media were Lactobacillus, while in other samples Alphaproteobacteria prevailed. Staphylococcus sp. was found only in semen from patients with inflammation. Phylum Bacteroidetes was in negative correlation with sperm motility and Alphaproteobacteria with high-quality IVF embryos.

CONCLUSION

Our study demonstrates that IVF does not occur in a sterile environment. The prevalent bacteria include classes Bacilli in raw semen and IVF culture media, Clostridia in processed and Bacteroidia in sperm samples used for insemination. The presence of Staphylococcus sp. and Alphaproteobacteria associated with clinical outcomes, like sperm and embryo quality.

Detection of bacteria in bovine ovarian follicular fluid

The aim of this study was to examine the sterility of follicular fluid in large ovarian follicles in dairy cows. In all, 17 samples of paired follicular fluids and uterine contents collected from post-slaughtered dairy cows were cultured to detect aerobic and facultative anaerobic bacteria. Furthermore, the origin of the bacterial isolates from samples of follicular fluid and the uteri was also investigated using PFGE analysis. Follicular fluid concentrations of lipopolysaccharides were also determined. Of 17 uterine samples, 15 (88%) were detected as contaminated. In total, nine different bacterial genera and species were identified in the uterine and follicular fluid samples. Escherichia coli was the most prevalent bacterial species isolated from the uterine samples. Out of seven isolates of Staphylococcus aureus from the uterine samples, 6 (85%) were coagulase positive. Six isolates of Staphylococcus spp. were identified in 6 out of 17 follicular fluid samples (35%). Two out of six isolates were identified as Staphylococcus aureus (33%). Our results show that ovarian follicular fluid is not sterile in the bovine. The presence of Staphylococcus aureus in follicular fluid may partly explain the occurrence of infertility in some dairy cows. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of the present study show that ovarian follicular fluid is not sterile in bovines. The presence of Staphylococcus aureus in follicular fluid may partly explain the occurrence of infertility in some dairy cows.

Microbial contamination in assisted reproductive technology: source, prevalence, and cost

Even the strictest laboratories and clinics are prone to the occurrence of microbial contamination. In the case of in vitro fertilization (IVF) research and practice facilities, the number of possible sources is particularly vast. In addition to ambient air, personnel, and non-sterilized materials, follicular fluid and semen from patients are a very common gateway for a diverse range of bacteria and fungi into embryo cultures. Even so, reports of contamination cases are rare, what leads many clinics to see the issue as a negligible risk. Microbiological contamination may result in the demise of the patient's embryos, leading to additional costs to both the patient and the clinics. Regardless of financial loss, emotional costs, and stress levels during IVF are highly distressing. Other worrisome consequences include DNA fragmentation, poor-quality embryos, early pregnancy loss or preterm birth, and possible long-term damages that need further investigation. In this review, we aimed to shed a light on the issue that we consider largely underestimated and to be the underlying cause of poor IVF outcomes in many cases. We also discuss the composition of the microbiome and how its interaction with the reproductive tract of IVF-seeking patients might influence their outcomes. In conclusion, we urge clinics to more rigorously identify, register, and report contamination occurrences, and highlight the role of the study of the microbiome to improve overall results and safety of assisted reproduction.

Role of endoplasmic reticulum stress in lipopolysaccharide-inhibited mouse granulosa cell estradiol production

The decrease in the level of estradiol (E₂) in granulosa cells caused by lipopolysaccharide (LPS) is one of the major causes of infertility underlying postpartum uterine infections; the precise molecular mechanism of which remains elusive. This study investigated the role of endoplasmic reticulum (ER) stress in LPS-induced E₂ decrease in mouse granulosa cells. Our results showed that LPS increased the pro-inflammatory cytokines [(interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor (TNF)-α)], activated ER stress marker protein expression [(glucose-regulated protein 78 (GRP78) and CCAAT/enhancer-binding protein homologous protein (CHOP)], and decreased cytochrome P450 family 19 subfamily A member 1 (Cyp19a1) expression and E₂ production. Moreover, inhibition of ER stress by 4-phenylbutyrate (4-PBA) attenuated thapsigargin-(TG, ER stress agonist) or LPS-induced reduction of Cyp19a1 and E₂, pro-inflammatory cytokines expression (IL-1β, IL-6, IL-8, and TNF-α), and the expression of CHOP and GRP78. Additionally, inhibition of toll-like receptor 4 (TLR4) by resatorvid (TAK-242) reversed the inhibitory effects of LPS on Cyp19a1 expression and E₂ production, activation of GRP78 and CHOP, and expression of IL-1β, IL-6, IL-8, and TNF-α. In summary, our study suggests that ER stress is involved in LPS-inhibited E₂ production in mouse granulosa cells.

The high-risk human papillomavirus continuum along the female reproductive tract and its relationship to infertility and endometriosis

RESEARCH QUESTION

Is there an association between the presence of sexually transmitted pathogens in the lower (LGT) and upper (UGT) female genital tract with endometriosis and infertility?

DESIGN

Case-control study with 60 women submitted to gynaecological laparoscopic surgery. Samples from the UGT and LGT were collected and analysed by single polymerase chain reaction (PCR) for human papillomavirus (HPV) and by multiplex PCR for other sexually transmitted infections (STI). Patients were initially divided into two clinical groups: infertile patients (n = 25) with conjugal infertility and fertile control patients (n = 35). After the surgical findings patients were further divided for additional analysis: an endometriosis group (n = 29) and non-endometriosis control group (n = 31).

RESULTS

Sixty per cent of patients were positive for DNA-HPV in some of the genital tract sites sampled. Infertile patients were associated with high-risk HPV (hrHPV) positivity in the UGT sites (P = 0.027). The endometriosis group was associated with hrHPV positivity in the LGT and UGT sites (P = 0.0002 and P = 0.03, respectively). Only hrHPV types were detected in the UGT in both groups. It may be that there is a hrHPV infection continuum, from LGT to UGT, in infertile and endometriosis patients. No association was observed among the other seven STI studied.

CONCLUSIONS

This study shows both an association between hrHPV infections in the UGT with infertility and endometriosis, and a possible hrHPV infection continuum, from LGT to UGT. Larger studies are needed to fully investigate the role of hrHPV as a cause of endometriosis and infertility.

The matter of the reproductive microbiome

The preconceptional presence of microbiota in the female and male reproductive organs suggests that fertilization is taking place in a nonsterile environment and contributes to reproductive success. The concept of embryonic development in a sterile uterus has also been challenged with recent reports of the existence of a microbiome of the placenta, amniotic fluid and the fetal gut in normal, uncomplicated pregnancies. The maternal origins of the microbiota colonising the fetus and its surroundings are unknown as are the mechanisms of maternal-to-fetal transfer. In this review, we aim to highlight the preconception male and female microbiome, the maternal vaginal and gut microbiome during pregnancy and the fetal microbiome, including their possible roles in reproduction, and maternal and neonatal pregnancy outcome.

Human granulosa-luteal cells initiate an innate immune response to pathogen-associated molecules

The microenvironment of the ovarian follicle is key to the developmental success of the oocyte. Minor changes within the follicular microenvironment can significantly disrupt oocyte development, compromising the formation of competent embryos and reducing fertility. Previously described as a sterile environment, the ovarian follicle of women has been shown to contain colonizing bacterial strains, whereas in domestic species, pathogen-associated molecules are concentrated in the follicular fluid of animals with uterine infection. The aim of this study is to determine whether human granulosa-luteal cells mount an innate immune response to pathogen-associated molecules, potentially disrupting the microenvironment of the ovarian follicle. Human granulosa-luteal cells were collected from patients undergoing assisted reproduction. Cells were cultured in the presence of pathogen-associated molecules (LPS, FSL-1 and Pam3CSK4) for 24h. Supernatants and total RNA were collected for assessment by PCR and ELISA. Granulosa-luteal cells were shown to express the molecular machinery required to respond to a range of pathogen-associated molecules. Expression of TLR4 varied up to 15-fold between individual patients. Granulosa-luteal cells increased the expression of the inflammatory mediators IL1B, IL6 and CXCL8 in the presence of the TLR4 agonist E. coli LPS. Similarly, the TLR2/6 ligand, FSL-1, increased the expression of IL6 and CXCL8. Although no detectable changes in CYP19A1 or STAR expression were observed in granulosa-luteal cells following challenge, a significant reduction in progesterone secretion was measured after treatment with FSL-1. These findings demonstrate the ability of human granulosa-luteal cells to respond to pathogen-associated molecules and generate an innate immune response.

Evaluating lipopolysaccharide-induced oxidative stress in bovine granulosa cells

PURPOSE

The purpose of this study was to evaluate the capacity of bovine granulosa cells to generate reactive oxygen intermediates in response to lipopolysaccharide. We hypothesized that granulosa cells increase reactive oxygen intermediates in response to Gram-negative lipopolysaccharide in a similar manner to immune cells.

METHODS

Bovine peripheral blood mononuclear cells and granulosa cells were cultured in the presence of lipopolysaccharide. Oxidative stress was evaluated using the fluorescent marker dye CellROX, and oxidative stress-related genes were measured using real-time RT-PCR.

RESULTS

As expected, peripheral blood mononuclear cells increased oxidative stress in response to lipopolysaccharide as measured by accumulation of the fluorescent marker dye CellROX. While granulosa cells demonstrate the capacity to increase accumulation of CellROX dye in response to a positive control menadione, lipopolysaccharide had no effect on accumulation of CellROX dye. The expression of GSR, SOD1, and SOD2 were variable in peripheral blood mononuclear cells treated with lipopolysaccharide but were consistently upregulated when co-incubated with the antioxidant, N-acetyl cysteine. The expression of oxidative stress-related genes was not altered in granulosa cells, with the exception of elevated SOD1 following lipopolysaccharide exposure in the absence of antioxidant.

CONCLUSIONS

Combined, these data suggest that while reactive stress is important in pathogen killing and inflammation in immune cells, granulosa cells do not increase oxidative stress in response to lipopolysaccharide.

Regulation of interleukin-11 expression in ovulatory follicles of the rat ovary

The aim of the present study was to examine the regulation of interleukin (IL)-11 expression, as well as the role of IL-11, during ovulation in gonadotropin-primed immature rats. Injection of equine chorionic gonadotropin (eCG), followed by human CG (hCG) to induce superovulation stimulated expression of the Il11 gene in theca cells within 6 h, as revealed by northern blot and in situ hybridisation analyses. Real-time reverse transcription–polymerase chain reaction analysis showed that the IL-11 receptor, α subunit gene was expressed in granulosa and theca cells and that injection of hCG had no effect on its expression. IL-11 protein expression was stimulated in theca cells by hCG. LH-stimulated increases in Il11 mRNA levels in cultured preovulatory follicles were inhibited by protein kinase A and mitogen-activated protein kinase kinase inhibitors. Toll-like receptor (TLR) 2 and TLR4 were detected in preovulatory follicles, and the TLR4 ligand lipopolysaccharide, but not the TLR2 ligand Pam3Cys, increased Il11 mRNA levels in theca cells, but not in granulosa cells. Treatment of preovulatory follicles with IL-11 stimulated progesterone production and steroidogenic acute regulatory protein (Star) gene expression. Together, these results indicate that IL-11 in theca cells is stimulated by mitogen-activated protein kinase signalling and TLR4 activation, and increases progesterone production during ovulation.

The Salivary Microbiome in Polycystic Ovary Syndrome (PCOS) and Its Association with Disease-Related Parameters: A Pilot Study

Background: Polycystic ovary syndrome (PCOS) is a common female endocrine condition of unclear etiology characterized by hyperandrogenism, oligo/amenorrhoea, and polycystic ovarian morphology. PCOS is often complicated by infertility, overweight/obesity, insulin resistance, and low-grade inflammation. The gut microbiome is known to contribute to several of these conditions. Recently, an association between stool and saliva microbiome community profiles was shown, making saliva a possible convenient, non-invasive sample type for detecting gut microbiome changes in systemic disease. In this study, we describe the saliva microbiome of PCOS patients and the association of microbiome features with PCOS-related parameters.

Methods: 16S rRNA gene amplicon sequencing was performed on saliva samples from 24 PCOS patients and 20 healthy controls. Data processing and microbiome analyses were conducted in mothur and QIIME. All study subjects were characterized regarding reproductive, metabolic, and inflammatory parameters.

Results: PCOS patients showed a decrease in bacteria from the phylum Actinobacteria and a borderline significant shift in bacterial community composition in unweighted UniFrac analysis. No differences between patients and controls were found in alpha diversity, weighted UniFrac analysis, or on other taxonomic levels. We found no association of saliva alpha diversity, beta diversity, or taxonomic composition with serum testosterone, oligo/amenorrhoea, overweight, insulin resistance, inflammatory markers, age, or diet.

Conclusions: In this pilot study, patients with PCOS showed a reduced salivary relative abundance of Actinobacteria. Reproductive and metabolic components of the syndrome were not associated with saliva microbiome parameters, indicating that the majority of between-subject variation in saliva microbiome profiles remains to be explained.

Characterisation of the human uterine microbiome in non-pregnant women through deep sequencing of the V1-2 region of the 16S rRNA gene

Background. It is widely assumed that the uterine cavity in non-pregnant women is physiologically sterile, also as a premise to the long-held view that human infants develop in a sterile uterine environment, though likely reflecting under-appraisal of the extent of the human bacterial metacommunity. In an exploratory study, we aimed to investigate the putative presence of a uterine microbiome in a selected series of non-pregnant women through deep sequencing of the V1-2 hypervariable region of the 16S ribosomal RNA (rRNA) gene.

Methods. Nineteen women with various reproductive conditions, including subfertility, scheduled for hysteroscopy and not showing uterine anomalies were recruited. Subjects were highly diverse with regard to demographic and medical history and included nulliparous and parous women. Endometrial tissue and mucus harvesting was performed by use of a transcervical device designed to obtain endometrial biopsy, while avoiding cervicovaginal contamination. Bacteria were targeted by use of a barcoded Illumina MiSeq paired-end sequencing method targeting the 16S rRNA gene V1-2 region, yielding an average of 41,194 reads per sample after quality filtering. Taxonomic annotation was pursued by comparison with sequences available through the Ribosomal Database Project and the NCBI database.

Results. Out of 183 unique 16S rRNA gene amplicon sequences, 15 phylotypes were present in all samples. In some 90% of the women included, community architecture was fairly similar inasmuch B. xylanisolvens, B. thetaiotaomicron, B. fragilis and an undetermined Pelomonas taxon constituted over one third of the endometrial bacterial community. On the singular phylotype level, six women showed predominance of L. crispatus or L. iners in the presence of the Bacteroides core. Two endometrial communities were highly dissimilar, largely lacking the Bacteroides core, one dominated by L. crispatus and another consisting of a highly diverse community, including Prevotella spp., Atopobium vaginae, and Mobiluncus curtisii.

Discussion. Our findings are, albeit not necessarily generalizable, consistent with the presence of a unique microbiota dominated by Bacteroides residing on the endometrium of the human non-pregnant uterus. The transcervical sampling approach may be influenced to an unknown extent by endocervical microbiota, which remain uncharacterised, and therefore warrants further validation. Nonetheless, consistent with our understanding of the human microbiome, the uterine microbiota are likely to have a previously unrecognized role in uterine physiology and human reproduction. Further study is therefore warranted to document community ecology and dynamics of the uterine microbiota, as well as the role of the uterine microbiome in health and disease.

A Dormant Microbial Component in the Development of Preeclampsia

Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.

Prevalence of Ureaplasma urealyticum and Mycoplasma hominis in High Vaginal Swab Samples of Infertile Females

Background:

Mycoplasma hominis and Ureaplasma urealyticum are important causative agents of vaginitis, cervicitis, postpartum sepsis, reproductive infections and infertility in both males and females.

Objectives:

According to the uncertain prevalence of U. urealyticum and M. hominis in Iranian infertile females, the present study was carried out to determine the prevalence of U. urealyticum and M. hominis in high vaginal swab samples of fertile and infertile females.

Patients and Methods:

A total of 350 high vaginal swab specimens were taken from fertile and infertile females. Samples were cultured and those that were positive for bacteria were subjected to the polymerase chain reaction (PCR) for further confirmation.

Results:

Of the 350 collected samples, eleven were positive for M. hominis (3.14%), fifteen were positive for U. urealyticum (4.28%) and five were positive for both of them (1.42%). Prevalence of U. urealyticum and M. hominis in the high vaginal parts of infertile females was higher than fertile females (P < 0.05). The results of traditional method were also confirmed, using the PCR amplification of urease gene of U. urealyticum and 16SrRNA gene of the M. hominis.Ureaplasma urealyticum and M. hominis had a higher prevalence in the high vaginal samples collected during the summer season.

Conclusions:

Considerable prevalence of M. hominis and U. urealyticum in the high vaginal swab samples of infertile females compared to the low prevalence in fertile females may suggest that these two pathogens can be cause infertility. Application of the PCR method is recommended for rapid and sensitive detection of M. hominis and U. urealyticum in high vaginal swab samples.

Gynecologic health and disease in relation to the microbiome of the female reproductive tract

It is well established that the vagina is colonized by bacteria that serve important roles in homeostasis. Imbalances in the proportion of bacteria may lead to a predisposition to infection or reproductive complications. Molecular-based approaches demonstrated a greater degree of microbial diversity both within and between women than previously recognized. The vaginal microbiome may fluctuate during various states of health, such as during the menstrual cycle or after menopause, and there may be differences in the vaginal microbiome between women of different ethnicities. Furthermore, the specific composition of the vaginal microbiome may influence the predisposition to dysbiosis and the transmission of sexually transmitted infections. An understanding of the diversity of the vaginal microbial environment during states of health is essential for the identification of risk factors for disease and the development of appropriate treatment.

TUNEL analysis of DNA fragmentation in mouse unfertilized oocytes: the effect of microorganisms within human follicular fluid collected during IVF cycles

Recently we reported the presence of bacteria within follicular fluid. Previous studies have reported that DNA fragmentation in human spermatozoa after in vivo or in vitro incubation with bacteria results in early embryo demise and a reduced rate of ongoing pregnancy, but the effect of bacteria on oocytes is unknown. This study examined the DNA within mouse oocytes after 12 hours' incubation within human follicular fluids (n=5), which were collected from women undergoing in vitro fertilization (IVF) treatment. Each follicular fluid sample was cultured to detect the presence of bacteria. Terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling (TUNEL) was used to label DNA fragmentation in ovulated, non-fertilized mouse oocytes following in vitro incubation in human follicular fluid. The bacteria Streptococcus anginosus and Peptoniphilus spp., Lactobacillus gasseri (low-dose), L. gasseri (high-dose), Enterococcus faecalis, or Propionibacterium acnes were detected within the follicular fluids. The most severe DNA fragmentation was observed in oocytes incubated in the follicular fluids containing P. acnes or L. gasseri (high-dose). No DNA fragmentation was observed in the mouse oocytes incubated in the follicular fluid containing low-dose L. gasseri or E. faecalis. Low human oocyte fertilization rates (<29%) were associated with extensive fragmentation in mouse oocytes (80-100%). Bacteria colonizing human follicular fluid in vivo may cause DNA fragmentation in mouse oocytes following 12h of in vitro incubation. Follicular fluid bacteria may result in poor quality oocytes and/or embryos, leading to poor IVF outcomes.

Microorganisms within human follicular fluid: effects on IVF

Our previous study reported microorganisms in human follicular fluid. The objective of this study was to test human follicular fluid for the presence of microorganisms and to correlate these findings with the in vitro fertilization (IVF) outcomes. In this study, 263 paired follicular fluids and vaginal swabs were collected from women undergoing IVF cycles, with various causes for infertility, and were cultured to detect microorganisms. The cause of infertility and the IVF outcomes for each woman were correlated with the microorganisms detected within follicular fluid collected at the time of trans-vaginal oocyte retrieval. Microorganisms isolated from follicular fluids were classified as: (1) ‘colonizers’ if microorganisms were detected within the follicular fluid, but not within the vaginal swab (at the time of oocyte retrieval); or (2) ‘contaminants’ if microorganisms detected in the vagina at the time of oocyte retrieval were also detected within the follicular fluid. The presence of Lactobacillus spp. in ovarian follicular fluids was associated with embryo maturation and transfer. This study revealed microorganisms in follicular fluid itself and that the presence of particular microorganisms has an adverse affect on IVF outcomes as seen by an overall decrease in embryo transfer rates and pregnancy rates in both fertile and infertile women, and live birth rates in women with idiopathic infertility. Follicular fluid microorganisms are a potential cause of adverse pregnancy outcomes in IVF in both infertile women and in fertile women with infertile male partners.

Hormone-dependent bacterial growth, persistence and biofilm formation--a pilot study investigating human follicular fluid collected during IVF cycles

Human follicular fluid, considered sterile, is aspirated as part of an in vitro fertilization (IVF) cycle. However, it is easily contaminated by the trans-vaginal collection route and little information exists in its potential to support the growth of microorganisms. The objectives of this study were to determine whether human follicular fluid can support bacterial growth over time, whether the steroid hormones estradiol and progesterone (present at high levels within follicular fluid) contribute to the in vitro growth of bacterial species, and whether species isolated from follicular fluid form biofilms. We found that bacteria in follicular fluid could persist for at least 28 weeks in vitro and that the steroid hormones stimulated the growth of some bacterial species, specifically Lactobacillus spp., Bifidobacterium spp. Streptococcus spp. and E. coli. Several species, Lactobacillus spp., Propionibacterium spp., and Streptococcus spp., formed biofilms when incubated in native follicular fluids in vitro (18/24, 75%). We conclude that bacteria aspirated along with follicular fluid during IVF cycles demonstrate a persistent pattern of growth. This discovery is important since it can offer a new avenue for investigation in infertile couples.

Lipopolysaccharide initiates inflammation in bovine granulosa cells via the TLR4 pathway and perturbs oocyte meiotic progression in vitro

Infections of the reproductive tract or mammary gland with Gram-negative bacteria perturb ovarian function, follicular growth, and fecundity in cattle. We hypothesized that lipopolysaccharide (LPS) from Gram-negative bacteria stimulates an inflammatory response by ovarian granulosa cells that is mediated by Toll-like receptor (TLR) 4. The present study tested the capacity of bovine ovarian granulosa cells to initiate an inflammatory response to pathogen-associated molecular patterns and determined subsequent effects on the in vitro maturation of oocytes. Granulosa cells elicited an inflammatory response to pathogen-associated molecular patterns (LPS, lipoteichoic acid, peptidoglycan, or Pam3CSK4) with accumulation of the cytokine IL-6, and the chemokine IL-8, in a time- and dose-dependent manner. Granulosa cells responded acutely to LPS with rapid phosphorylation of TLR signaling components, p38 and ERK, and increased expression of IL6 and IL8 mRNA, although nuclear translocation of p65 was not evident. Targeting TLR4 with small interfering RNA attenuated granulosa cell accumulation of IL-6 in response to LPS. Endocrine function of granulosa cells is regulated by FSH, but here, FSH also enhanced responsiveness to LPS, increasing IL-6 and IL-8 accumulation. Furthermore, LPS stimulated IL-6 secretion and expansion by cumulus-oocyte complexes and increased rates of meiotic arrest and germinal vesicle breakdown failure. In conclusion, bovine granulosa cells initiate an innate immune response to LPS via the TLR4 pathway, leading to inflammation and to perturbation of meiotic competence.