Microbiological characteristics and inflammatory cytokines associated with preterm labor

Th17/Treg Cell Imbalance May Contribute to Spontaneous Preterm Labor

Spontaneous preterm labor (SPTL) is a major cause of neonatal mortality and severe complications. T cells play a crucial role in mediating inflammation and immune tolerance at the maternal-fetal interface. T helper 17 cells (Th17, pro-inflammatory) and regulatory T cells (Treg, anti-inflammatory) are two subsets of CD4+ T cells with opposite functions, and their balance is important for maintaining immune homeostasis. Since infection and inflammation represent prominent factors responsible for the pathogenesis of SPTL, Th17/Treg imbalance at the maternal-fetal interface may trigger proinflammatory responses, potentially leading to SPTL. In this review, evidence from both clinical cases of SPTL and animal models indicates the presence of Th17/Treg imbalance in both peripheral blood and the maternal-fetal interface. Additionally, interleukin-6 (IL-6), interleukin-1β (IL-1β), and interleukin-8 (IL-8) have been involved in the pathogenesis of inflammation-induced SPTL, suggesting that Th17/Treg imbalance may have relevance to and be involved in the pathogenic process of SPTL. Moreover, the presence of Th17/Treg imbalance in risk factors for SPTL, such as autoimmune diseases and bacterial infections, further supports this connection indirectly. Although predictive models and interventional strategies related to SPTL have been explored, there is currently insufficient evidence to establish a direct causal relationship between Th17/Treg imbalance and the onset of SPTL.

Describing Biological Vulnerability in Small, Vulnerable Newborns in Urban Burkina Faso (DenBalo): Gut Microbiota, Immune System, and Breastmilk Assembly

Background: Small vulnerable newborns (SVNs), including those born preterm, small for gestational age, or with low birth weight, are at higher risk of neonatal mortality and long-term health complications. Early exposure to maternal vaginal microbiota and breastfeeding plays a critical role in the development of the neonatal microbiota and immune system, especially in low-resource settings like Burkina Faso, where neonatal mortality rates remain high. Objectives: The DenBalo study aims to investigate the role of maternal and neonatal factors, such as vaginal and gut microbiota, immune development, and early nutrition, in shaping health outcomes in SVNs and healthy infants. Methods: This prospective cohort observational study will recruit 141 mother-infant pairs (70 SVNs and 71 healthy controls) from four health centers in Bobo-Dioulasso, Burkina Faso. The mother-infant pairs will be followed for six months with anthropometric measurements and biospecimen collections, including blood, breast milk, saliva, stool, vaginal swabs, and placental biopsies. Multi-omics approaches, encompassing metagenomics, metabolomics, proteomics, and immune profiling, will be used to assess vaginal and gut microbiota composition and functionality, immune cell maturation, and cytokine levels at critical developmental stages. Conclusions: This study will generate comprehensive data on how microbiota, metabolomic, and proteomic profiles, along with immune system development, differ between SVNs and healthy infants. These findings will guide targeted interventions to improve neonatal health outcomes and reduce mortality, particularly in vulnerable populations.

Candidiasis in Pregnancy: Relevant Aspects of the Pathology for the Mother and the Fetus and Therapeutic Strategies

Vulvovaginal candidiasis (VVC) is a common condition that can lead to significant discomfort, affecting approximately 70-75% of women at least once in their lives. During pregnancy, the prevalence of VVC is estimated to be around 20%, peaking at about 30% in the third trimester, with a number of specific risk factors predisposing to yeast infection being identified and needing elucidation. This review aims to provide updated knowledge on candidiasis during pregnancy, addressing risk factors and maternal and neonatal outcomes, as well as discussing optimal therapeutic strategies to safeguard mothers and newborns. The bibliographic search involved two biomedical databases, PubMed and Embase, without imposing time limits. Among all Candida spp., Candida albicans remains the most frequent causative species. The hyperestrogenic environment of the vaginal mucosa and reduced immune defenses, physiological effects of pregnancy, create conditions favorable for Candida spp. vaginal colonization and hence VVC. Recent evidence shows an association between VVC and adverse obstetric outcomes, including premature membrane rupture (PROM), chorioamnionitis, preterm birth, and puerperal infections. Prompt and effective management of this condition is therefore crucial to prevent adverse obstetric outcomes, maternal-fetal transmission, and neonatal disease. Additional studies are required to confirm the benefits of systemic treatment for maternal candida infection or colonization in preventing premature birth or neonatal systemic candidiasis.

Vulvovaginal yeast infections during pregnancy and perinatal outcomes: systematic review and meta-analysis

BACKGROUND

Vulvovaginal yeast infections in pregnancy are common and can cause extensive inflammation, which could contribute to adverse pregnancy outcomes. Symptomatic yeast infections are likely to cause more inflammation than asymptomatic. The objective of this study was to investigate associations between symptomatic and asymptomatic vulvovaginal yeast infections in pregnancy and perinatal outcomes.

METHODS

We did a systematic review and searched eight databases until 01 July 2022. We included studies reporting on pregnant women with and without laboratory confirmed vulvovaginal yeast infection and preterm birth or eight other perinatal outcomes. We used random effects meta-analysis to calculate summary odds ratios (OR), 95% confidence intervals (CI) and prediction intervals for the association between yeast infection and outcomes. We described findings from studies with multivariable analyses. We assessed the risk of bias using published tools.

RESULTS

We screened 3909 references and included 57 studies. Only 22/57 studies reported information about participant vulvovaginal symptoms. Preterm birth was an outcome in 35/57 studies (49,161 women). In 32/35 studies with available data, the summary OR from univariable analyses was 1.01 (95% CI 0.84-1.21, I2 60%, prediction interval 0.45-2.23). In analyses stratified by symptom status, we found ORs of 1.44 (95% CI 0.92-2.26) in two studies with ≥ 50% symptomatic participants, 0.84 (95% CI 0.45-1.58) in seven studies with < 50% symptomatic participants, and 1.12 (95% CI 0.94-1.35) in four studies with asymptomatic participants. In three studies with multivariable analysis, adjusted ORs were greater than one but CIs were compatible with there being no association. We did not find associations between vulvovaginal yeast infection and any secondary outcome. Most studies were at high risk of bias in at least one domain and only three studies controlled for confounding.

CONCLUSIONS

We did not find strong statistical evidence of an increased risk for preterm birth or eight other adverse perinatal outcomes, in pregnant women with either symptomatic or asymptomatic vulvovaginal yeast infection. The available evidence is insufficient to make recommendations about testing and treatment of vulvovaginal yeast infection in pregnancy. Future studies should assess vulvovaginal symptoms, yeast organism loads, concomitant vaginal or cervical infections, and microbiota using state-of-the-art diagnostics.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020197564.

Maternal HIV, antiretroviral timing, and spontaneous preterm birth in an urban Zambian cohort: the role of local and systemic inflammation

OBJECTIVE

To assess plasma and vaginal inflammation in three antenatal groups (HIV-uninfected women, HIV-infected women entering care on preconceptional ART, and HIV-infected women not on preconceptional ART) and whether these measures are associated with spontaneous preterm birth (sPTB).

DESIGN

Case--control study nested within a pregnancy cohort in Lusaka, Zambia.

METHODS

We analyzed 11 pro-inflammatory and two anti-inflammatory markers in 207 women with paired plasma and vaginal specimens collected between 16 and 20 gestational weeks. Among 51 HIV-infected women, we repeated the assays in 24-34-week samples. We used confirmatory factor analysis to create inflammation scores and compared them among the three groups.

RESULTS

At baseline, HIV-infected women not on ART had higher vaginal pro-inflammatory scores than HIV-uninfected women [mean 0.37 (95% CI -0.06 to 0.80) vs. -0.02 (-0.32 to 0.27), P = 0.02]. In repeat testing, women not on preconceptional ART had an increase in vaginal inflammation between the baseline and 24-34-week visits compared with those continuing preconceptional ART [mean 0.62 (95% CI -0.80 to 4.20) vs. -0.07 (-2.78 to 2.11), P = 0.04]. In multivariate analyses, baseline vaginal inflammation predicted sPTB (aOR 1.5; 95% CI 1.0-2.3; P = 0.02). Plasma inflammation did not differ by HIV or ART exposure and was not associated with sPTB.

CONCLUSION

Women not receiving ART at entry into pregnancy care had more vaginal inflammation than women entering on treatment. They also experienced an increase in vaginal inflammation between the two sampling timepoints, possibly as a consequence of ART initiation. Vaginal (but not systemic) inflammation was associated with sPTB and offers a potential mechanistic insight into this important adverse birth outcome.

Microengineered hiPSC-Derived 3D Amnion Tissue Model to Probe Amniotic Inflammatory Responses under Bacterial Exposure

Intra-amniotic infection is a common cause of preterm birth that can lead to adverse neonatal outcomes. Despite the basic and clinical significance, the study in normal and diseased human amnion is highly challenging due to the limited use of human primary tissues and the distinct divergence between animal models and human. Here, we established a microengineered hiPSC-derived amnion tissue model on a chip to investigate the inflammatory responses of amnion tissues to bacterial exposure. The microdevice consisted of two parallel channels with a middle matrix channel, creating a permissive microenvironment for amnion differentiation. Dissociated hiPSCs efficiently self-organized into cell cavity and finally differentiated into a polarized squamous amniotic epithelium on the chip under perfused 3D culture. When exposed to E. coli, amnion tissue exhibited significant functional impairments compared to the control, including induced cell apoptosis, disrupted cell junction integrity, and increased inflammatory factor secretion, recapitulating a series of characteristic clinical signs of intra-amniotic infection at an early stage. Together, this amnion-on-a-chip model provides a promising platform to investigate intrauterine inflammation in early gestation, indicating its potential applications in human embryology and reproductive medicine.

Group B Streptococcus colonization induces Prevotella and Megasphaera abundance-featured vaginal microbiome compositional change in non-pregnant women

Background

Previous studies have indicated that variations in the vaginal microbiome result in symptomatic conditions. Group B Streptococcus (GBS) is a significant neonatal pathogen and maternal vaginal colonization has been recognized as an important risk factor for neonatal disease. Therefore, it is important to discover the relationship between the composition of the vaginal microbiome and GBS colonization. This study explores the potential relationship between the composition of the vaginal microbiome and GBS colonization in non-pregnant Chinese women.

Methods

A total of 22 GBS-positive, non-pregnant women and 44 matched GBS-negative women were recruited for the current study. The composition of the vaginal microbiome was profiled by sequencing the 16S rRNA genes. The microbiome diversity and variation were then evaluated.

Results

The vaginal microbiome of the 66 subjects enrolled in the current study were compared and the results showed that GBS-positive women exhibited significant vaginal microbial differences compared with the GBS-negative women based on the analysis of similarities (r = 0.306, p < 0.01). The relative abundance of the bacterial genus Lactobacillus (p < 0.01) was significantly lower in the GBS-positive group, while the abundances of the bacterial genera Prevotella (p < 0.01), Megasphaera (p < 0.01), and Streptococcus (p < 0.01) were significantly higher in the GBS-positive group.

Discussion

The current study addressed significant variations across the communities of the vaginal microbiome in GBS-positive and GBS-negative women in a Chinese cohort, which paves the way for a larger cohort-based clinical validation study and the development of therapeutic probiotics in the future.

Optimising the collection of female genital tract fluid for cytokine analysis in pregnant women

Introduction

To better understand the immunology of pregnancy, study of female genital tract fluid (FGF) is desirable. However the optimum method of collection of FGF in pregnant women for immunological methods, specifically cytokine measurement, is unknown.

Methods

A prospective study of HIV-uninfected pregnant women comparing two methods of FGF collection: polyvinyl acetal sponge collection of cervical fluid (CF) and menstrual cup collection of cervicovaginal fluid (CVF). Samples were collected at 3 time points across the second and third trimesters: 14–21, 22–25 and 26–31 weeks. Multiplex chemi-luminescent assays were used to measure: IFN-γ, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13 and TNF-α. Optimal methodology for cytokine normalisation (sample weight, volume and total protein) was explored.

Results

All cytokines were measurable in both fluid types. IL-1β, IL-8 and IL-6 were detected at the highest concentrations (ranking order CF > CVF > plasma). CVF collection was simpler, provided the largest volume of sample (median 0.5 g) with the potential for undiluted usage, and allowed for self-insertion. CF cytokine concentrations were intrinsically associated with sample weight and protein concentration however CVF cytokines were independent of these.

Conclusion

Both methods of collection are robust for measurement of FGF cytokines during pregnancy. We recommend CVF collection using a menstrual cup as a viable option in pregnant women for high dimensional biological techniques.

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PVA sponges and MCs are robust methods for measuring FGF cytokines in pregnancy.

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MCs enable collection of large undiluted CVF volumes for high dimensional assays.

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CVF (not CF) cytokine concentrations are largely independent of sample weight or protein.

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Self-insertion and short collection time of MCs is an attractive option to women.

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Cytokine concentrations are higher in sponge samples reflecting the CF immune site.

Preterm Birth Associated With Group B Streptococcus Maternal Colonization Worldwide: Systematic Review and Meta-analyses

BACKGROUND

Preterm birth complications are the leading cause of deaths among children <5 years of age. Studies have suggested that group B Streptococcus (GBS) maternal rectovaginal colonization during pregnancy may be a risk factor for preterm delivery. This article is the fifth of 11 in a series. We aimed to assess the association between GBS maternal colonization and preterm birth in order to inform estimates of the burden of GBS.

METHODS

We conducted systematic literature reviews (PubMed/Medline, Embase, Latin American and Caribbean Health Sciences Literature [LILACS], World Health Organization Library Information System [WHOLIS], and Scopus) and sought unpublished data from investigator groups on the association of preterm birth (<37 weeks' gestation) and maternal GBS colonization (GBS isolation from vaginal, cervical, and/or rectal swabs; with separate subanalysis on GBS bacteriuria). We did meta-analyses to derive pooled estimates of the risk and odds ratios (according to study design), with sensitivity analyses to investigate potential biases.

RESULTS

We identified 45 studies for inclusion. We estimated the risk ratio (RR) for preterm birth with maternal GBS colonization to be 1.21 (95% confidence interval [CI], .99-1.48; P = .061) in cohort and cross-sectional studies, and the odds ratio to be 1.85 (95% CI, 1.24-2.77; P = .003) in case-control studies. Preterm birth was associated with GBS bacteriuria in cohort studies (RR, 1.98 [95% CI, 1.45-2.69]; P < .001).

CONCLUSIONS

From this review, there is evidence to suggest that preterm birth is associated with maternal GBS colonization, especially where there is evidence of ascending infection (bacteriuria). Several biases reduce the chance of detecting an effect. Equally, however, results, including evidence for the association, may be due to confounding, which is rarely addressed in studies. Assessment of any effect on preterm delivery should be included in future maternal GBS vaccine trials.

Escherichia coli-induced temporal and differential secretion of heat-shock protein 70 and interleukin-1β by human fetal membranes in a two-compartment culture system

INTRODUCTION

Escherichia coli is recognized as an etiological bacteria associated with chorioamnionitis and the preterm premature rupture of fetal membranes. This pathological condition induces pro-inflammatory cytokines and degradative metalloproteinases, which are considered biological markers secreted in an acute stage of infection. Heat-shock proteins (HSPs) are an important component of the innate immunity response and are found in different pathological conditions. They have not been previously measured in human fetal membranes in response to infectious conditions. We hypothesized that the choriodecidual tissue and amniotic epithelium secreted temporal and differential Hsp-60, Hsp-70, and interleukin (IL)-1β mediated by E. coli infection.

METHODS

Fetal membranes were mounted in a two-compartment culture system and infected with two passes of live E. coli at different doses (10², 10⁴, 10⁵, and 10⁶ colony-forming units (CFU)/mL) and intervals of incubation (3, 6, and 24 h). The culture medium was collected, and Hsp-60, Hsp-70, and IL-1β were assessed using the enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

After 3 and 6 h of infection, E. coli induced an increase in Hsp-70 secretion in the choriodecidual tissue. However, after 24 h of incubation, Hsp-70 was downregulated and we observed an increase in IL-1β secretion. By contrast, E. coli induced a lower Hsp-60 secretion in the amnion compared to Hsp-70.

DISCUSSION

Human fetal membranes responded actively to E. coli infection, with an increase in Hsp-70 during the first hours of infection. After 24 h, there was an increase in the liberation of IL-1β.

Is severe OHSS associated with adverse pregnancy outcomes? Evidence from a case-control study

Ovarian hyperstimulation syndrome (OHSS) is a serious and potentially life-threatening complication of fertility treatment. This study evaluated pregnancy outcomes of women hospitalized for severe OHSS. A case-control study was performed of 125 women who were hospitalized due to severe OHSS compared with a control group, consisting of 156 women matched by age and aetiology of infertility, who conceived via IVF and did not develop OHSS. Among women with singleton pregnancies, patients with severe OHSS delivered significantly earlier (37.96 versus 39.11 weeks) and had smaller babies (2854 g versus 3142 g) compared with the matched controls. Similarly, rates of preterm delivery (<34 weeks of gestation: 8.9% versus 0%, P < 0.01; <37 weeks of gestation: 20.5% versus 5.1%, P < 0.01) were significantly increased among patients in the study group. There were no between-group differences in the rates of gestational diabetes, gestational hypertension and intrauterine growth restriction. In contrast, twin pregnancies following OHSS were not significantly different from matched control twins, with regard to the rates of delivery <34 weeks and <37 weeks of gestation, gestational diabetes, gestational hypertension and intrauterine growth restriction. In conclusion, severe OHSS at early gestation is associated with adverse pregnancy outcome only in singleton gestations.

Preterm birth and single nucleotide polymorphisms in cytokine genes

Preterm birth (PTB) is an important issue in neonates because of its complications as well as high morbidity and mortality. The prevalence of PTB is approximately 12-13% in USA and 5-9% in many other developed countries. China represents 7.8% (approximately one million) of 14.9 million babies born prematurely annually worldwide. The rate of PTB is still increasing. Both genetic susceptibility and environmental factors are the major causes of PTB. Inflammation is regarded as an enabling characteristic factor of PTB. The aim of this review is to summarize the current literatures to illustrate the role of single nucleotide polymorphisms (SNPs) of cytokine genes in PTB. These polymorphisms are different among different geographic regions and different races, thus different populations may have different risk factors of PTB. SNPs affect the ability to metabolize poisonous substances and determine inflammation susceptibility, which in turn has an influence on reproduction-related risks and on delivery outcomes after exposure to environmental toxicants and pathogenic organisms.

Use of cervicovaginal fluid for the identification of biomarkers for pathologies of the female genital tract

Cervicovaginal fluid has an important function in the homeostasis and immunity of the lower female genital tract. Analysis of the cervicovaginal fluid proteome may therefore yield important information about the pathogenesis of numerous gynecological pathologies. Additionally, cervicovaginal fluid has great potential as a source of biomarkers for these conditions.

This review provides a detailed discussion about the human cervicovaginal proteome and the proteomics studies performed to characterize this biological fluid. Furthermore, infection-correlated pathological conditions of the female genital tract are discussed for which cervicovaginal fluid has been used in order to identify potential biomarkers. Recent years, numerous studies have analyzed cervicovaginal fluid samples utilizing antibody-based technologies, such as ELISA or Western blotting, to identify biomarkers for preterm birth, premature preterm rupture of membranes, bacterial vaginosis and cervical cancer. The present article will discuss the importance of proteomic technologies as alternative techniques to gain additional meaningful information about these conditions. In addition, the review focuses on recent proteomic studies on cervicovaginal fluid samples for the identification of potential biomarkers. We conclude that the use of proteomic technology for analysis of human cervicovaginal fluid samples is promising and may lead to the discovery of new biomarkers which can improve disease prevention and therapy development.