Porphyromonas gingivalis infection in pregnant mice is associated with placental dissemination, an increase in the placental Th1/Th2 cytokine ratio, and fetal growth restriction

Fetal growth restriction induced by maternal gal-3 deficiency is associated with altered gut-placenta axis

Adverse intrauterine conditions may cause fetal growth restriction (FGR), a pregnancy complication frequently linked to perinatal morbidity and mortality. Although many studies have focused on FGR, the pathophysiological processes underlying this disorder are complex and incompletely understood. We have recently determined that galectin-3 (gal-3), a β-galactoside-binding protein, regulates pregnancy-associated processes, including uterine receptibility, maternal vascular adaptation and placentation. Because gal-3 is expressed at both sides of the maternal-fetal interface, we unraveled the contribution of maternal- and paternal-derived gal-3 on fetal-placental development in the prenatal window and its effects on the post-natal period. Deficiency of maternal gal-3 induced maternal gut microbiome dysbiosis, resulting in a sex-specific fetal growth restriction mainly observed in female fetuses and offspring. In addition, poor placental metabolic adaptions (characterized by decreased trophoblast glycogen content and insulin-like growth factor 2 (Igf2) gene hypomethylation) were only associated with a lack of maternal-derived gal-3. Paternal gal-3 deficiency caused compromised vascularization in the placental labyrinth without affecting fetal growth trajectory. Thus, maternal-derived gal-3 may play a key role in fetal-placental development through the gut-placenta axis.

Ectopic colonization by oral bacteria as an emerging theme in health and disease

The number of research papers published on the involvement of the oral microbiota in systemic diseases has grown exponentially over the last 4 years clearly demonstrating the growing interest in this field. Indeed, accumulating evidence highlights the central role of ectopic colonization by oral bacteria in numerous noncommunicable diseases including inflammatory bowel diseases (IBDs), undernutrition, preterm birth, neurological diseases, liver diseases, lung diseases, heart diseases, or colonic cancer. There is thus much interest in understanding the molecular mechanisms that lead to the colonization and maintenance of ectopic oral bacteria. The aim of this review is to summarize and conceptualize the current knowledge about ectopic colonization by oral bacteria, highlight wherever possible the underlying molecular mechanisms and describe its implication in health and disease. The focus lies on the newly discovered molecular mechanisms, showcasing shared pathophysiological mechanisms across different body sites and syndromes and highlighting open questions in the field regarding the pathway from oral microbiota dysbiosis to noncommunicable diseases.

MicroRNA miR-27a as a possible regulator of anti-inflammatory macrophage phenotype in preeclamptic placenta

INTRODUCTION

The role of the TGFβ signaling pathway, an important cascade responsible for the anti-inflammatory polarization of macrophages, in the development of both early- and late-onset preeclampsia (eoPE and loPE), remains poorly understood. In this study, we examined the components of the TGFβ signaling cascade and macrophage markers within placental tissue in normal pregnancy and in PE.

METHODS

Patients with eoPE, loPE, and normal pregnancy were enrolled in the study (n = 10 in each group). Following techniques were used for the investigation: immunohistochemistry analysis, western blotting, qRT-PCR, isolation of monocytes by magnetic sorting, transfection, microRNA sequencing, and bioinformatic analysis.

RESULTS

We observed a significant decrease in the anti-inflammatory macrophage marker CD206 in the loPE group, alongside with a significant down-regulation of CD206 protein production in both eoPE and loPE groups. The level of CD68-positive cells and relative levels of CD163 and MARCO production were comparable across the groups. However, we identified a significant decrease in the TGFβ receptor 2 production and its gene expression in the PE group. Further analysis revealed a link between TGFBR2 and MRC1 (CD206) genes through a single miRNA, hsa-miR-27a-3p. Transfecting CD14-derived macrophages with the hsa-miR-27a-3p mimic significantly changed TGFBR2 production, indicating the potential role of this miRNA in regulating the TGFβ signaling pathway. We also revealed the up-regulation of hsa-miR-27a-5p and hsa-miR-27a-3p in the trophoblast BeWo b30 cell line under the severe hypoxia condition and the fact that TGFBR2 3' UTR could serve as a potential target for these miRNAs.

DISCUSSION

Our findings uncover a novel potential therapeutic target for managing patients with PE, significantly contributing to a deeper comprehension of the underlying mechanisms involved in the development of this pathology.

[Pathways and Mechanisms of Periodontitis Contributing to Adverse Pregnancy Outcomes]

Periodontitis is a chronic oral inflammatory disease with a high incidence in the global population. Periodontal pathogens can colonize and infect multiple human tissues and organs through blood transmission, which is an important risk factor of many systemic diseases. Recently, the correlation between periodontitis and adverse pregnancy outcomes (APOs) has attracted growing research interest. Herein, we systematically reviewed the research progress in the relationship between periodontitis and APOs and summarized reported findings on the pathways and mechanisms by which periodontitis contributes to APOs. We also clarified that intrauterine infection caused by oral pathogens transmitted through blood is an important pathway by which periodontitis interferes with pregnancy. In addition, further research focused on the discovery of more APOs-related oral pathogenic bacteria and their virulence factors, analysis of the interaction between pathogenic bacteria and placental tissue, and pathogenic pathways of oral bacterial invasion of the fetus will promote thorough analysis of the specific molecular mechanism of how periodontitis affects APOs. Furthermore, the validation of the results of human population-based studies through animal/cell experiments and the translation into effective intervention strategies are of great clinical significance to the prevention and control of the occurrence and development of APOs.

The fecal microbiota of gravidas with fetal growth restriction newborns characterized by metagenomic sequencing

BACKGROUND

Fetal growth restriction (FGR) is a complex obstetric complication with various causes and of great harm. However, the specific pathogenesis of FGR is unclear, which limits its effective treatment. Gut microbiota dysbiosis was found to be important in pathogenesis of various diseases. However, its role in FGR development remains unclear and needs to be clarified.

METHODS

In our case-control study, we recruited eight FGR and eight control female participants and collected their fecal samples in third trimester before delivery. We performed metagenomic sequencing and bioinformatic analysis to compare the gut microbiota composition and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways between the two groups.

RESULTS

Our results showed that totally 20 gut microbes were significantly different between two groups (p<0•05), and the correlation analysis found that g__Roseomonas and g__unclassified_f__Propionibacteriaceae were significantly positive correlated with both maternal body mass index (BMI) before delivery, placental weight, and neonatal birth weight (BW) percentile (all p<0•05), while g__Marinisporobacter and g__Sphingomonas were significantly negative correlated with both neonatal BMI and neonatal BW percentile (all p<0•05). Through KEGG pathway analysis, we found that the abundance of the Nitrogen metabolism pathway decreased significantly (p<0•05) whereas the abundance of the Amoebiasis pathway increased significantly in the FGR group (p<0•05).

CONCLUSION

In this study, we demonstrated that the occurrence of FGR is associated with the change of gut microbiota of pregnant women.

Emerging and legacy PFAS and cytokine homeostasis in women of childbearing age

Per- and polyfluoroalkyl substances (PFAS) are widespread chemicals. Legacy PFAS have been phased out of production in most developed countries and emerging PFAS (short-chain PFAS and polyfluorinated compounds) are used as legacy PFAS alternatives. The effect of legacy and emerging PFAS on cytokine homeostasis in human remains poorly understood. This study aimed to evaluate the associations between legacy and emerging PFAS and cytokine profiles, and identify the main contributors to the disturbance of cytokine homeostasis. We quantified 21 PFAS in 198 Chinese women of childbearing age from 2015 to 2016. 13 cytokines were measured using the Meso Scale Discovery U-PLEX and V-PLEX platforms. The associations between PFAS exposure and cytokine levels were assessed using multiple linear regression (single-exposure), and Bayesian kernel machine regression (BKMR) models (PFAS mixture exposure). In single PFAS models, legacy and alternative PFAS were positively associated with Th1 and Treg cytokines, and negatively associated with Th2 and Th17 cytokines. For instance, each ln-unit increase in 6:2 chlorinated perfluoroalkyl ether sulfonic acid (6:2 Cl-PFESA), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonate (PFOS) was associated with a decrease in IL-10 by − 0.228 (95% CI: − 0.336, − 0.120), − 0.153 (95% CI: − 0.277, − 0.030), and − 0.174 (95% CI: − 0.339, − 0.010), respectively. The BKMR model showed a significantly positive association of PFAS mixture with TGF-β and a negative association with IL-10. Overall, these results indicate that both legacy and emerging PFAS may affect the homeostasis of cytokines.

The Maternal-Fetal Gut Microbiota Axis: Physiological Changes, Dietary Influence, and Modulation Possibilities

The prenatal period and the first years of life have a significant impact on the health issues and life quality of an individual. The appropriate development of the immune system and the central nervous system are thought to be major critical determining events. In parallel to these, establishing an early intestinal microbiota community is another important factor for future well-being interfering with prenatal and postnatal developmental processes. This review aims at summarizing the main characteristics of maternal gut microbiota and its possible transmission to the offspring, thereby affecting fetal and/or neonatal development and health. Since maternal dietary factors are potential modulators of the maternal-fetal microbiota axis, we will outline current knowledge on the impact of certain diets, nutritional factors, and nutritional modulators during pregnancy on offspring's microbiota and health.

Oral bacteria, oral health, and adverse pregnancy outcomes

The link between oral health and adverse pregnancy outcomes has been suggested by numerous epidemiological studies. More recent studies indicate the relationship between severity of periodontal disease and adverse pregnancy outcomes. Two virulence mechanisms are proposed: direct invasion of oral microorganisms or their components into the fetal-placenta unit and inflammatory mediators produced in the oral cavity affecting the fetal-placenta unit. While interventional periodontal therapy still yielded contradictory results, animal studies suggest that maternal supplementation of omega-3 fatty acids protects the fetus by suppressing inflammation as well as bacteria proliferation in the placenta. This article reviews the recent epidemiological, mechanistic, interventional, and therapeutic studies of oral health and adverse pregnancy outcomes.

Understanding the pathways leading to gut dysbiosis and enteric environmental dysfunction in infants: the influence of maternal dysbiosis and other microbiota determinants during early life

Maternal environmental enteric dysfunction (EED) encompasses undernutrition with an inflammatory gut profile, a variable degree of dysbiosis and increased translocation of pathogens in the gut mucosa. Even though recent research findings have shed light on the pathological pathways underlying the establishment of the infant gut dysbiosis, evidence on how maternal EED influences the development of gut dysbiosis and EED in the offspring remains elusive. This review summarizes the current knowledge on the effect of maternal dysbiosis and EED on infant health, and explores recent progress in unraveling the mechanisms of acquisition of a dysbiotic gut microbiota in the offspring. In Western communities, maternal inoculum, delivery mode, perinatal antibiotics, feeding practices, and infections are the major drivers of the infant gut microbiota during the first two years of life. In other latitudes, the infectious burden and maternal malnutrition might introduce further risk factors for infant gut dysbiosis. Novel tools, such as transcriptomics and metabolomics, have become indispensable to analyze the metabolic environment of the infant in utero and post-partum. Human-milk oligosaccharides have essential prebiotic, antimicrobial, and anti-biofilm properties that might offer additional therapeutic opportunities.

Hofbauer cells and coronavirus disease 2019 (COVID-19) in pregnancy: Molecular pathology analysis of villous macrophages, endothelial cells, and placental findings from 22 placentas infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with and without fetal transmission

CONTEXT

- Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can undergo maternal-fetal transmission, heightening interest in the placental pathology findings from this infection. Transplacental SARS-CoV-2 transmission is typically accompanied by chronic histiocytic intervillositis together with necrosis and positivity of syncytiotrophoblast for SARSCoV-2. Hofbauer cells are placental macrophages that have been involved in viral diseases including HIV and Zika virus, but their involvement in SARS-CoV-2 in unknown.

OBJECTIVE

- To determine whether SARS-CoV-2 can extend beyond the syncytiotrophoblast to enter Hofbauer cells, endothelium and other villous stromal cells in infected placentas of liveborn and stillborn infants.

DESIGN

- Case-based retrospective analysis by 29 perinatal and molecular pathology specialists of placental findings from a preselected cohort of 22 SARS-CoV-2-infected placentas delivered to pregnant women testing positive for SARS-CoV-2 from 7 countries. Molecular pathology methods were used to investigate viral involvement of Hofbauer cells, villous capillary endothelium, syncytiotrophoblast and other fetal-derived cells.

RESULTS

- Chronic histiocytic intervillositis and trophoblast necrosis was present in all 22 placentas (100%). SARS-CoV-2 was identified in Hofbauer cells from 4/22 placentas (18%). Villous capillary endothelial staining was positive in 2/22 cases (9%), both of which also had viral positivity in Hofbauer cells. Syncytiotrophoblast staining occurred in 21/22 placentas (95%). Hofbauer cell hyperplasia was present in 3/22 placentas (14%). In the 7 cases having documented transplacental infection of the fetus, 2 occurred in placentas with Hofbauer cell staining positive for SARS-CoV-2.

CONCLUSIONS

- SARS-CoV-2 can extend beyond the trophoblast into the villous stroma, involving Hofbauer cells and capillary endothelial cells, in a small number of infected placentas. Most cases of SARS-CoV-2 transplacental fetal infection occur without Hofbauer cell involvement.

Salmonella Enteritidis foodborne infection induces altered placental morphometrics in the murine model

INTRODUCTION

Salmonella foodborne disease during pregnancy causes a significant fetal loss in domestic livestock and preterm birth, chorioamnionitis and miscarriage in humans. These complications could be associated with alterations in placental structure. This study was aimed to determine how a low dose of Salmonella Enteritidis during late gestation affects placental histomorphometric in mice.

METHODS

We used a self-limiting enterocolitis murine model. BALB/c pregnant animals received a low dose of Salmonella Enteritidis (3-4 x 10² CFU/mouse) on gestational day (GD) 15. At day 3 post infection bacterial loads, serum cytokines expression and placental histomorphometrics parameters were analyzed.

RESULTS

We found that a sub-lethal infection with Salmonella induced a significant drop in fetal weight -to-placental weight-ratio and an increase in the placental coefficient. After bacterial inoculation maternal organs were colonized, inducing placental morphometric alterations, including increased placental thickness, reduced surface area, and diminished major and minor diameters. Also, foci of necrosis accompanied by acute leukocyte infiltration in decidual zone, reduction of vascular spaces and vascular congestion in labyrinth zone, were also evident in placentas from infected females on GD 18. Our data shows that placentas from infected mothers are phenotypically different from control ones. Furthermore, expression of IFN-gamma and IL-6 was up regulated in response to Salmonella in maternal serum.

DISCUSSION

Our findings demonstrate that a low dose of Salmonella during late gestation alters the placental morphometry leading to negative consequences on pregnancy outcome such as significant reduction in fetal body weight.

Oral microbiome and pregnancy: A bidirectional relationship

The oral cavity contains the second most complex microbial population within the human body, with more than 700 bacterial organisms. Recent advances in Next Generation Sequencing technology have unraveled the complexities of the oral microbiome and provided valuable insights into its role in health and disease. The human oral microbiome varies dramatically during the different stages of life, including pregnancy. The total viable microbial counts in pregnant women are known to be higher compared to non-pregnant women, especially in the first trimester of pregnancy. A balanced oral microbiome is vital for a healthy pregnancy, as perturbations in the oral microbiome composition can contribute to pregnancy complications. On the other hand, physiological changes and differences in hormonal levels during pregnancy, increase susceptibility to various oral diseases such as gingivitis and periodontitis. A growing body of evidence supports the link between the composition of the oral microbiome and adverse pregnancy outcomes such as preterm birth, preeclampsia, low birth weight among others. This review aims to summarize the dynamics of oral microbiome during pregnancy and to discuss the relationship between a dysbiotic oral microbiome and pregnancy complications.

Gestational gut microbial remodeling is impaired in a rat model of preeclampsia superimposed on chronic hypertension

Preeclampsia is a progressive hypertensive disorder of pregnancy affecting 2%-8% of pregnancies globally. Preexisting chronic hypertension is a major risk factor associated with developing preeclampsia, and growing evidence suggests a role for the gut microbiome in the development of preeclampsia. However, neither alterations in the gut microbiome associated with preeclampsia nor the mechanisms involved are fully understood. In this study, we tested the hypothesis that normal gestational maternal gut microbiome remodeling is impaired in the Dahl salt-sensitive (Dahl S) rat model of superimposed preeclampsia. Gut microbiome profiles of pregnant Dahl S, normal pregnant Sprague-Dawley (SD), and matched virgin controls were assessed by 16S rRNA gene sequencing at baseline; during early, middle, and late pregnancy; and 1-wk postpartum. Dahl S rats had significantly higher abundance in Proteobacteria, and multiple genera were significantly different from SD rats at baseline. The pregnant SD displayed a significant increase in Proteobacteria and genera such as Helicobacter, but these were not different between pregnant and virgin Dahl S rats. By late pregnancy, Dahl S rats had significantly lower α-diversity and Firmicutes compared with their virgin Dahl S controls. β-diversity was significantly different among groups (P < 0.001). KEGG metabolic pathways including those associated with short-chain fatty acids were different in Dahl S pregnancy but not in SD pregnancy. These results reveal an association between chronic hypertension and gut microbiome dysbiosis which may hinder pregnancy-specific remodeling in the gut microbial composition during superimposed preeclampsia.

Moderate and severe periodontitis are positively associated with metabolic syndrome

OBJECTIVE

This study investigated the association between periodontitis severity (exposure) and metabolic syndrome (MetS - outcome), using two criteria for diagnosis of the outcome, since this relationship remains unexplored.

MATERIALS AND METHODS

A case-control study was conducted with 870 individuals: 408 with first MetS diagnosis (cases) and 462 without MetS (controls). Participants' general information was obtained using a questionnaire and laboratory data was collected from medical records. Periodontitis severity criteria followed the Center for Disease Control and Prevention: none, mild, moderate, and severe. Odds ratios (OR) and 95% confidence intervals (95% CI) were determined by logistic regression analysis.

RESULTS

Findings showed a positive association between moderate and severe periodontitis and MetS: OR_adjusted = 1.64 (95% CI: 1.01 to 2.68) and OR_adjusted = 1.94 (95% CI: 1.19 to 3.16), respectively, after adjustment for age, sex, schooling level, smoking habit, and cardiovascular disease. The adjusted measurements showed that among individuals with moderate or severe periodontitis, the probability of having MetS was around two times greater than among those without periodontitis, and that the chance was greater among participants with severe periodontitis than those with moderate periodontitis.

CONCLUSION

An association between the severity of periodontal status and MetS was found, suggesting a possible relationship between the two diseases.

CLINICAL RELEVANCE

MetS influences the etiology of cardiovascular diseases, one of the leading causes of mortality worldwide. The findings suggest that the greater the severity of periodontitis, the greater is the association magnitude with MetS. The health professional needs to recognize that the importance of periodontal disease may play in MetS.

Porphyromonas gingivalis and Its Systemic Impact: Current Status

The relationship between periodontitis and systemic diseases, notably including atherosclerosis and diabetes, has been studied for several years. Porphyromonas gingivalis, a prominent component of oral microorganism communities, is the main pathogen that causes periodontitis. As a result of the extensive analysis of this organism, the evidence of its connection to systemic diseases has become more apparent over the last decade. A significant amount of research has explored the role of Porphyromonas gingivalis in atherosclerosis, Alzheimer's disease, rheumatoid arthritis, diabetes, and adverse pregnancy outcomes, while relatively few studies have examined its contribution to respiratory diseases, nonalcoholic fatty liver disease, and depression. Here, we provide an overview of the current state of knowledge about Porphyromonas gingivalis and its systemic impact in an aim to inform readers of the existing epidemiological evidence and the most recent preclinical studies. Additionally, the possible mechanisms by which Porphyromonas gingivalis is involved in the onset or exacerbation of diseases, together with its effects on systemic health, are covered. Although a few results remain controversial, it is now evident that Porphyromonas gingivalis should be regarded as a modifiable factor for several diseases.

Therapeutic Efficacy of Phage PIZ SAE-01E2 against Abortion Caused by Salmonella enterica Serovar Abortusequi in Mice

Salmonella enterica subsp. enterica serovar Abortusequi is a frequently reported pathogen causing abortion in mares. In this study, the preventive and therapeutic effects of phage P_IZ SAE-01E2 against S Abortusequi in a mouse model of abortion were investigated. Phage P_IZ SAE-01E2 was stable at different temperatures (4 to 70°C) and pH values (pH 4 to 10) and could lyse the majority of the Salmonella serogroup O:4 and O:9 strains tested (25/28). There was no lysogeny-related, toxin, or antibiotic resistance-related gene in the genome of P_IZ SAE-01E2. All of these characteristics indicate that P_IZ SAE-01E2 has the potential for use in phage therapy. In in vivo experiments, 2 × 10³ CFU/mouse of S Abortusequi ATCC 9842 was sufficient to lead to murine abortion (gestational day 14.5) within 48 h. A single intraperitoneal inoculation of P_IZ SAE-01E2 (10⁸ PFU/mouse, multiplicity of infection = 10⁵) 1 h before or after S Abortusequi challenge provided effective protection to all pregnant mice (10/10). After 24 h of treatment with phage P_IZ SAE-01E2, the bacterial loads in both the placenta and the uterus of the infected mice were significantly decreased (<10² CFU/g) compared to those in the placenta and the uterus of the mice in the control group (>10⁶ CFU/g). In addition, the levels of inflammatory cytokines in the placenta and blood of the mice in the phage administration groups were significantly reduced (P < 0.05) compared to those in the placenta and blood of the mice in the control group. Altogether, these findings indicate that P_IZ SAE-01E2 shows the potential to block abortions induced by S Abortusequi in vivo IMPORTANCE S Abortusequi is an important pathogen that can induce abortions in mares. Although S Abortusequi has been well controlled in Europe and the United States due to strict breeding and health policies, it is still widespread in African and Asian countries and has proven difficult to control. In China, abortions caused by S Abortusequi have also been reported in donkeys. So far, there is no commercial vaccine. Thus, exploiting alternative efficient and safe strategies to control S Abortusequi infection is essential. In this study, a new lytic phage, P_IZ SAE-01E2, infecting S Abortusequi was isolated, and the characteristics of P_IZ SAE-01E2 indicated that it has the potential for use in phage therapy. A single intraperitoneal inoculation of P_IZ SAE-01E2 before or after S Abortusequi challenge provided effective protection to all pregnant mice. Thus, P_IZ SAE-01E2 showed the potential to block abortions induced by S Abortusequi in vivo.

Fetal growth restriction is a host specific response to infection with an impaired spiral artery remodeling-inducing strain of Porphyromonas gingivalis

Porphyromonas gingivalis is a periodontal pathogen implicated in a range of pregnancy disorders that involve impaired spiral artery remodeling (ISAR) with or without fetal growth restriction (FGR). Using a rodent periodontitis model, we assessed the ability of P. gingivalis to produce ISAR and FGR in Sprague Dawley (SD) and Wistar (WIS) rats. Both infected SD and WIS rats developed ISAR, but only WIS rats developed FGR despite both rat strains having equivalent microbial loads within the placenta. Neither maternal systemic inflammation nor placental (fetal) inflammation was a feature of FGR in WIS rats. Unique to infected WIS rats, was loss of trophoblast cell density within the junctional zone of the placenta that was not present in SD tissues. In addition, infected WIS rats had a higher proportion of junctional zone trophoblast cells positive for cytoplasmic high temperature requirement A1 (Htra1), a marker of cellular oxidative stress. Our results show a novel phenomenon present in P. gingivalis-induced FGR, with relevance to human disease since dysregulation of placental Htra1 and placental oxidative stress are features of preeclamptic placentas and preeclampsia with FGR.

Periodontal disease and adverse pregnancy outcomes

Periodontal diseases are considered not only to affect tooth-supporting tissues but also to have a cause-and-effect relationship with various systemic diseases and conditions, such as adverse pregnancy outcomes. Mechanistic studies provide strong evidence that periodontal pathogens can translocate from infected periodontium to the feto-placental unit and initiate a metastatic infection. However, the extent and mechanisms by which metastatic inflammation and injury contribute to adverse pregnancy outcomes still remain unclear. The presence of oral bacteria in the placenta of women with term gestation further complicates our understanding of the biology behind the role of periodontal pathogens in pregnancy outcomes. Epidemiological studies demonstrate many methodological inconsistencies and flaws that render comparisons difficult and conclusions insecure. Therefore, despite the fact that a number of prospective studies show a positive association between periodontal diseases and various adverse pregnancy outcomes, the evidence behind it is still weak. Future well-designed explanatory studies are necessary to verify this relationship and, if present, determine its magnitude. The majority of high-quality randomized controlled trials reveal that nonsurgical periodontal therapy during the second trimester of gestation does not improve pregnancy outcomes. From a biological standpoint, this can be partially explained by the fact that therapy rendered at the fourth to sixth months of pregnancy is too late to prevent placental colonization by periodontal pathogens and consequently incapable of affecting pathogen-induced injury at the feto-placental unit. Thus, interventions during the preconception period may be more meaningful. With the increase in our understanding on the potential association between periodontal disease and adverse pregnancy outcomes, it is clear that dental practitioners should provide periodontal treatment to pregnant women that is safe for both the mother and the unborn child. Although there is not enough evidence that the anti-infective therapy alters pregnancy outcomes, it improves health-promoting behavior and periodontal condition, which in turn advance general health and risk factor control.

The periodontopathic bacteria in placenta, saliva and subgingival plaque of threatened preterm labor and preterm low birth weight cases: a longitudinal study in Japanese pregnant women

OBJECTIVES

This study determined the quantity of periodontopathic bacteria in saliva, subgingival plaque, and placenta on the threatened preterm labor (TPL) and preterm low birth weight (PLBW) subjects in order to identify specific periodontal pathogens with high association to adverse pregnancy outcomes.

METHODS

We used real-time PCR with TaqMan probe and ELISA to detect the amount of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Fusobacterium nucleatum, and Prevotella intermedia in subgingival plaque, saliva, and placenta tissue, in addition to serum IgG titers against these bacteria in 28 patients with TPL and 36 healthy pregnant women.

RESULTS

Thirteen of 64 births delivered PLBW infants. All 6 periodontopathic bacteria were detected in the placenta samples. The amount of F. nucleatum and detection frequency of T. denticola in placental samples was significantly higher in the TPL group than in the healthy group. Meanwhile, the age, anti-P. gingival IgG in serum, amount of P. gingivalis and T. forsythia in plaque samples, detection frequency of P. intermedia in saliva, and percentage of pocket probing depth ≥ 5 mm were higher in TPL-PLBW births than those in TPL-Healthy delivery (HD) group and/or in H-HD group. Ordinal logistic regression analysis revealed that the presence of F. nucleatum in placental tissues was significantly associated with TPL, while the maternal age was significantly associated with PLBW in TPL.

CONCLUSION

Our findings suggested all 6 bacteria may access the placenta. The increased presence of F. nucleatum in placenta might be related to TPL, while advanced maternal age might be associated with PLBW in TPL.

CLINICAL RELEVANCE

Periodontal therapy should be applied to reduce the deep periodontal pocket sites and the colonization of periodontal pathogens in high-risk population.

Porphyromonas gingivalis and adverse pregnancy outcomes: a review on its intricate pathogenic mechanisms

Porphyromonas gingivalis (P. gingivalis), a Gram-negative facultative anaerobe of the oral cavity, is associated with the onset of various adverse pregnancy outcomes. P. gingivalis is linked with the development of preeclampsia, preterm labour, spontaneous abortion, gestational diabetes, foetal growth restriction, and misconception. The unique virulence factors, surface adhesions, enzymes of P. gingivalis can directly injure and alter the morphology, microbiome the foetal and maternal tissues. P. gingivalis can even exaggerate the production of cytokines, free radicals and acute-phase proteins in the uterine compartment that increases the risk of myometrial contraction and onset of preterm labour. Although evidence confirms the presence of P. gingivalis in the amniotic fluid and placenta of women with poor pregnancy outcomes, the intricate molecular mechanisms by which P. gingivalis initiates various antenatal and postnatal maternal and foetal complications are not well explained in the literature. Therefore, the present review aims to comprehensively summarise and highlight the recent and unique molecular pathogenic mechanisms of P. gingivalis associated with adverse pregnancy outcomes.

Unveiling the pathophysiology of gestational diabetes: Studies on local and peripheral immune cells

Gestational diabetes mellitus (GDM) has been associated with impaired maternal immune response. Our aim was to review the available literature linking immune cells profile to GDM, in order to comprehend the role that different subpopulations play in the development of this pathology. We searched in PubMed for studies published in the last decade on circulating levels and placenta expression of immune cells on GDM. We identified 18 studies with several differences regarding the study design, clinical characteristics, number of participants, cell subpopulation and type of sample. Most studies assessed only one subpopulation either in peripheral blood or placenta and did not analyse functional properties of the cells. The most frequently evaluated immune cells were T lymphocytes, especially regulatory T (Tregs), and natural killer (NK) cells in the peripheral blood, and placental macrophages. No studies analysing B cells were identified, and only one study each evaluating γδT cells, dendritic cell (DC) and monocytes was found. Although there are controversies, at least one study reported positive association between GDM and CD4⁺ (activated), Tregs, Th17 and γδT cells; neutrophil/lymphocyte; NK cell (cytotoxic); macrophages; and monocytes. The number of studies is still small, so caution should be exercised in interpreting the data, and further research is required to validate these findings and establish the role of adaptive and innate immune cells in GDM pathophysiology.

Evidence that intra-amniotic infections are often the result of an ascending invasion - a molecular microbiological study

Background Microbial invasion of the amniotic cavity resulting in intra-amniotic infection is associated with obstetrical complications such as preterm labor with intact or ruptured membranes, cervical insufficiency, as well as clinical and histological chorioamnionitis. The most widely accepted pathway for intra-amniotic infection is the ascension of microorganisms from the lower genital tract. However, hematogenous dissemination of microorganisms from the oral cavity or intestine, retrograde seeding from the peritoneal cavity through the fallopian tubes, and introduction through invasive medical procedures have also been suggested as potential pathways for intra-amniotic infection. The primary reason that an ascending pathway is viewed as most common is that the microorganisms most often detected in the amniotic fluid are those that are typical inhabitants of the vagina. However, thus far, no studies have shown that microorganisms in the amniotic cavity are simultaneously present in the vagina of the woman from which they were isolated. The objective of the study was to determine the frequency with which microorganisms isolated from women with intra-amniotic infection are also present in the lower genital tract. Methods This was a cross-sectional study of women with intra-amniotic infection with intact membranes. Intra-amniotic infection was defined as a positive culture and elevated concentrations of interleukin-6 (IL-6) (>2.6 ng/mL) in amniotic fluid and/or acute histologic chorioamnionitis and funisitis. Microorganisms isolated from bacterial cultures of amniotic fluid were taxonomically identified through matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF) and 16S ribosomal RNA (rRNA) gene sequencing. Vaginal swabs were obtained at the time of amniocentesis for the identification of microorganisms in the lower genital tract. The overall bacterial profiles of amniotic fluids and vaginal swabs were characterized through 16S rRNA gene sequencing. The bacterial profiles of vaginal swabs were interrogated for the presence of bacteria cultured from amniotic fluid and for the presence of prominent (>1% average relative abundance) operational taxonomic units (OTUs) within the overall 16S rRNA gene bacterial profiles of amniotic fluid. Results (1) A total of 75% (6/8) of women had bacteria cultured from their amniotic fluid that are typical residents of the vaginal ecosystem. (2) A total of 62.5% (5/8) of women with bacteria cultured from their amniotic fluid also had these bacteria present in their vagina. (3) The microorganisms cultured from amniotic fluid and also detected in the vagina were Ureaplasma urealyticum, Escherichia coli, and Streptococcus agalactiae. (4) 16S rRNA gene sequencing revealed that the amniotic fluid of women with intra-amniotic infection had bacterial profiles dominated by Sneathia, Ureaplasma, Prevotella, Lactobacillus, Escherichia, Gardnerella, Peptostreptococcus, Peptoniphilus, and Streptococcus, many of which had not been cultured from the amniotic fluid samples. (5) Seventy percent (7/10) of the prominent (>1% average relative abundance) OTUs found in amniotic fluid were also prominent in the vagina. Conclusion The majority of women with intra-amniotic infection had bacteria cultured from their amniotic fluid that were typical vaginal commensals, and these bacteria were detected within the vagina at the time of amniocentesis. Molecular microbiological interrogation of amniotic fluid from women with intra-amniotic infection revealed that the bacterial profiles of amniotic fluid were largely consistent with those of the vagina. These findings indicate that ascension from the lower genital tract is the primary pathway for intra-amniotic infection.

Placental colonization with periodontal pathogens: the potential missing link

Observational studies demonstrate that women with severe periodontitis have a higher risk of adverse pregnancy outcomes like preterm birth and low birthweight. Standard treatment for periodontitis in the form of scaling and root planing during the second trimester failed to reduce the risk of preterm or low birthweight. It is premature to dismiss the association between periodontitis and adverse pregnancy outcomes because one explanation for the failure of scaling and root planing to reduce the risk of adverse pregnancy outcomes is that periodontal pathogens spread to the placental tissue prior to periodontal treatment. In the placenta, orally derived organisms could cause direct tissue damage or mediate a maternal immune response that impairs the growth of the developing fetus. Sequencing studies demonstrate the presence of organisms derived from the oral microbiome in the placenta, but DNA-based sequencing studies should not be the only technique to evaluate the placental microbiome because they may not detect important shifts in the metabolic capability of the microbiome. In humans, polymerase chain reaction and histology have detected periodontal pathogens in placental tissue in association with multiple adverse pregnancy outcomes. We conclude that both placental and oral microbiomes may play a role in periodontitis-associated adverse pregnancy outcomes. However, the measure to determine the association between periodontal pathogens in the placenta and adverse pregnancy outcomes should be the amount and prevalence, not the mere presence of such microorganisms. Placental colonization with periodontal pathogens thus potentially represents the missing link between periodontitis and adverse pregnancy outcomes.

Fetal Weight Outcomes in C57BL/6J and C57BL/6NCrl Mice after Oral Colonization with Porphyromonas gingivalis

Porphyromonas gingivalis is considered a keystone pathogen that contributes to the initiation and progression of periodontitis in humans. P. gingivalis has also been detected in human placentas associated with adverse pregnancy outcomes. The spread of P. gingivalis from the oral cavity to the reproductive tract thus represents a potential mechanism whereby periodontitis can lead to adverse pregnancy outcomes. In a murine model of pregnancy and oral infection with P. gingivalis, C57BL/6J mice developed low fetal weight, whereas C57BL/6NCrl mice did not. Although C57BL/6NCrl mice harbor segmented filamentous bacteria that drive a Th17 response, fetal weight was independent of frequency of Th17 or Th1 in either substrain. Low fetal weight was instead correlated with increasing amounts of P. gingivalis DNA in the placentas of the C57BL/6J dams. In contrast, fetal weight in C57BL/6NCrl mice was independent of P. gingivalis in the placenta. Differences in genetics or microbiome that influence the ability of P. gingivalis to colonize the placenta may drive differential fetal weight outcomes between C57BL/6J and C57BL/6NCrl mice and, potentially, between diverse human populations.

Porphyromonas gingivalis strain-dependent inhibition of uterine spiral artery remodeling in the pregnant rat

Porphyromonas gingivalis (Pg) is an important periodontal pathogen that is also implicated in pregnancy complications involving defective deep placentation (DDP). We hypothesized that Pg invasion of the placental bed promotes DDP. Pregnant rats were intravenously inoculated with sterile vehicle, Pg strain W83, or A7436 at gestation day (GD) 14 (acute cohort). Nonpregnant rats received repeated oral inoculations for 3 months before breeding (chronic cohort). Tissues and/or sera were collected at GD18 for analysis. Pg infection status was determined by seroconversion (chronic cohort) and by presence of Pg antigen in utero-placental tissues processed for histology and morphometric assessment of spiral artery remodeling. Mesometrial tissues from seropositive dams were analyzed for expression of interleukin 1β, 6, and 10, TNF, TGF-β, follistatin-related protein 3, and inhibin beta A chain since these genes regulate extravillous trophoblast invasion. The in situ distribution of W83 and A7436 antigen in utero-placental tissues was similar in both cohorts. In the acute cohort, mesometrial stromal necrosis was more common with W83, but arteritis was more common with A7436 infection (P < 0.05). Increased vascular necrosis was seen in mesometrium of chronically infected groups (P < 0.05). Only A7436-infected animals had increased fetal deaths, reduced spiral artery remodeling, reduced inhibin beta A expression, and an increased proportion of FSLT3 positive extravillous trophoblasts within spiral arteries. While infection with both Pg strains produced varying pathology of the deep placental bed, only infection with strain A7436 resulted in impaired spiral artery remodeling.

Periodontal diseases and adverse pregnancy outcomes

From last decade of the 20th century, numerous epidemiological studies and intervention trials have attempted to prove the relationships between maternal periodontal diseases and adverse pregnancy outcomes (APO). Periodontal diseases are considered a risk factor for APO, including preterm birth, fetal growth restriction, low birthweight, pre-eclampsia and gestational diabetes. However, the efficacy of periodontal treatment during pregnancy is controversial. Two pathogenic mechanisms might explain the potential effect of periodontal diseases on pregnancy outcomes. First, periodontal bacteria originating in the gingival biofilm directly affect the feto-placental unit subsequent to bacteremia. Second, inflammatory mediators secreted by the subgingival inflammatory site are carried to the feto-placental unit, where they then cause an inflammatory response. To elucidate these mechanisms, many researchers have been investigating the use of experimental animal models and in vitro models. In the present review, we summarize the current literature on the relationship between periodontal diseases and APO from epidemiological studies, animal models studies and in vitro studies, and speculate on the possible mechanism of periodontal diseases affecting pregnancy outcomes.

Periodontal pathogens in the placenta and membranes in term and preterm birth

INTRODUCTION

Preterm birth is a common cause of adverse neonatal and childhood outcomes. It is commonly associated with infection of the maternal-fetal interface. The relationship between periodontitis and preterm labour is controversial.

METHODS

Control placental tissues from uncomplicated term births were compared with those from spontaneous preterm births for incidence of common periodontal bacteria. A chi-square analysis was used to compare the populations, with significance determined at p=<0.05.

RESULTS

The study group comprised 29 control women who had an uncomplicated term birth, 25 delivered by caesarean section and 4 vaginal deliveries, and 36 women with a spontaneous preterm labour and subsequent delivery at less than 34 weeks gestation. There were significant (p=<0.05) differences between the preterm and term groups maternal age with 28.7 compared to 32.0 years old respectively. There was no significant (p=>0.05) differences between the groups fetal risk factors or co-morbidities, except the preterm group had a significantly higher (p=<0.05) rate of premature rupture of membrane (PROM). There were significantly (p=<0.01) more Fusobacterium spp. in the placentas from term births than preterm births.

DISCUSSION

This study found that the common periodontal pathogen, Fusobacterium spp., is not detected more in placentas from preterm birth and may potentially be lower, possibly resulting from bacterial ecological factors in term placentas.

Progress in the understanding of the etiology and predictability of fetal growth restriction

Fetal growth restriction (FGR) is defined as the failure of fetus to reach its growth potential for various reasons, leading to multiple perinatal complications and adult diseases of fetal origins. Shallow extravillous trophoblast (EVT) invasion-induced placental insufficiency and placental dysfunction are considered the main reasons for idiopathic FGR. In this review, first we discuss the major characteristics of anti-angiogenic state and the pro-inflammatory bias in FGR. We then elaborate major abnormalities in placental insufficiency at molecular levels, including the interaction between decidual leukocytes and EVT, alteration of miRNA expression and imprinted gene expression pattern in FGR. Finally, we review current animal models used in FGR, an experimental intervention based on animal models and the progress of predictive biomarker studies in FGR.Free Chinese abstract: A Chinese translation of this abstract is freely available at http://www.reproduction-online.org/content/153/6/R215/suppl/DC1.

Galectin-3 Plays an Important Role in Preterm Birth Caused by Dental Infection of Porphyromonas gingivalis

Dental infection is risk for preterm birth (PTB) through unclear mechanisms. We established a dental infection-induced PTB mouse model, in which Porphyromonas gingivalis (P.g.) induced PTB by 2 days. We analysed pathogenic factors contributing to PTB and their effects on trophoblasts in vitro. TNF-α, IL-8, and COX-2 were upregulated in P.g.-infected placenta. Galectin-3 (Gal-3), an immune regulator, was significantly upregulated in placenta, amniotic fluid, and serum. In vitro, P.g.-lipopolysaccharide (P.g.-LPS) increased TNF-α and Gal-3 in trophoblasts via NF-κB/MAPK signalling. Gal-3 inhibition significantly downregulated P.g.-LPS-induced TNF-α production. TNF-α upregulated Gal-3. Gal-3 also increased cytokines and Gal-3 through NF-κB/MAPK signalling. Moreover, Gal-3 suppressed CD-66a expression at the maternal-foetal interface. Co-stimulation with Gal-3 and P.g.-LPS upregulated cytokine levels, while Gal-3 plus Aggregatibacter actinomycetemcomitans (A.a.)- or Escherichia coli (E. coli)-LPS treatment downregulated them, indicating the critical role of Gal-3 especially in P.g. dental infection-induced PTB. P.g.-dental infection induced PTB, which was associated with Gal-3-dependent cytokine production. New therapies and/or diagnostic systems targeting Gal-3 may reduce PTB.

Inhibition of gingipains prevents Porphyromonas gingivalis-induced preterm birth and fetal death in pregnant mice

Accumulating epidemiological evidence indicates that infection with Porphyromonas gingivalis which is a major periodontal pathogen, causes preterm birth and low birth weight. However, virulence factors of P. gingivalis responsible for preterm birth/low birth weight remain to be elucidated. In this study, using P. gingivalis-infected pregnant mice as an in vivo model, we investigated whether gingipains-cysteine proteinases produced by P. gingivalis-affect preterm birth and low birth weight. We found that intravenous infection of pregnant mice with P. gingivalis induced higher accumulation of the bacterium in the placenta than that in other organs. Compared to infection with P. gingivalis wild-type, infection with a gingipain-deficient P. gingivalis mutant KDP136 led to significant reduction in preterm birth and pregnancy loss. Although repetitive low-level infections of P. gingivalis failed to induce preterm birth and fetal death, it induced suppressive effects on IFN-γ production. Therapeutically, treatment with ginginpain inhibitors prevented fetal death and preterm birth caused by P. gingivalis infection and resulted in recovery of IFN-γ suppression caused by repetitive chronic P. gingivalis infection. These results indicate that gingipains are major virulence factors of P. gingivalis responsible for preterm birth/low birth, and gingipain inhibitors may be useful not only as a therapeutic agent for periodontal diseases, but also as a preventive medicine for preterm birth/low birth weight.

Periodontal Disease and Pregnancy Outcomes: Overview of Systematic Reviews

Periodontal disease is very common during pregnancy. Although it has been linked to adverse pregnancy outcomes, systematic reviews have reached discrepant conclusions on these links. Therefore, we conducted a systematic overview of systematic reviews studying the association between periodontal disease and adverse pregnancy outcomes. We searched 6 online databases up to November 2016 and hand-searched references and citations of eligible papers. Systematic reviews of studies comparing pregnancy outcomes among women with and without periodontal disease were eligible for inclusion. Primary outcomes were maternal mortality, preterm birth, and perinatal mortality. Two reviewers extracted data and assessed risk of bias of individual systematic reviews. Findings are described in tabular and narrative form. Twenty-three systematic reviews (including between 3 and 45 studies) were included. None reported the association between periodontal disease and maternal or perinatal mortality. Systematic reviews with the lowest risk of bias consistently demonstrated positive associations between periodontal disease and preterm birth (relative risk, 1.6; 95% confidence interval, 1.3 to 2.0; 17 studies, 6,741 participants), low birth weight (LBW; relative risk, 1.7; 95% CI, 1.3 to 2.1; 10 studies, 5,693 participants), preeclampsia (odds ratio, 2.2; 95% CI, 1.4 to 3.4; 15 studies, 5,111 participants), and preterm LBW (relative risk 3.4; 95% CI, 1.3 to 8.8; 4 studies, 2,263 participants). Based on these figures, estimated population-attributable fractions for periodontal disease were 5% to 38% for preterm birth, 6% to 41% for LBW, and 10% to 55% for preeclampsia. In terms of limitations, as several primary studies did not adjust for confounding, meta-analyses may have overestimated the strength of the associations under study. Due to substantial overlap in included primary studies, we could not aggregate results across reviews. Consistent evidence from systematic reviews with low risk of bias indicates that pregnant women with periodontal disease are at increased risk of developing preeclampsia and delivering a preterm and/or LBW baby (PROSPERO: CRD42015030132).

Knowledge Transfer Statement: This study highlights that periodontal disease is an important risk factor for several common adverse pregnancy outcomes. Clinicians should be aware of this link to guide risk selection. Research is needed to develop novel preventive and treatment strategies.

Porphyromonas gingivalis and adverse pregnancy outcome

Porphyromonas gingivalis is a Gram-negative, anaerobic bacterium considered to be an important pathogen of periodontal disease that is also implicated in adverse pregnancy outcome (APO). Until recently, our understanding of the role of P. gingivalis in APO has been limited and sometimes contradictory. The purpose of this review is to provide an overview of past and current research on P. gingivalis that addresses some of the controversies concerning the role of this organism in the pathogenesis of APO.

Human Placental Hofbauer Cells Maintain an Anti-inflammatory M2 Phenotype despite the Presence of Gestational Diabetes Mellitus

Background

Hofbauer cells (HBCs) are macrophages of the feto-placental unit. Despite the general view that these cells have an anti-inflammatory M2 phenotype, recent studies have claimed that pregnancy pathologies—e.g., gestational diabetes mellitus (GDM)—cause a switch from an M2 to an M1 pro-inflammatory phenotype in HBCs. The pilot-study presented here challenges this claim, showing that HBCs maintain anti-inflammatory properties in spite of the hyperglycemic, low-grade inflammatory environment of GDM.

Methods

HBCs were isolated from placentae of healthy women (N = 5) and women with GDM (N = 6) diagnosed in the second trimester. FACS was used to measure surface markers associated with either M1 or M2 phenotype on the cells. In addition, placental tissue sections were subjected to immune histochemical imaging to assess the phenotype within the tissue context. Supernatant from control and GDM HBCs was collected at defined time points and used in a multiplex ELISA-on-beads approach to assess secretion of cytokines, chemokines, and growth factors. The effect of HBC cell culture supernatant on placental endothelial activation was investigated.

Results

FACS and immune staining showed that, indeed, M2 markers, such as CD206 and CD209, are increased in HBCs isolated from GDM placentae. Also, the M1 marker CD86 was increased, but only by trend. Secretion of numerous cytokines, chemokines and growth factors was not changed; pro-inflammatory interleukin (IL)-1β and IL-6 release form GDM HBC was increased but not significant. Exposure to GDM HBC supernatant did not induce cell adhesion molecules (VCAM-1, selectins, vascular endothelial-cadherin) in placental endothelial cells compared to supernatant from control HBCs, an induction of intracellular adhesion molecule 1 was observed however.

Conclusion

Our study—although performed in a small set of patients—shows that placental macrophages maintain their anti-inflammatory, tissue remodeling M2 phenotype even in pregnancies affected by gestational diabetes. This consistent phenotype might be important for propagation of maternal tolerance toward the fetus and for protection of the fetus from a low-grade inflammatory environment.

Inflammation-induced fetal growth restriction in rats is associated with increased placental HIF-1α accumulation

Introduction

Hypoxia-inducible factor 1-alpha (HIF-1α) is the oxygen-sensitive subunit of the transcription factor HIF-1, and its expression is increased in placentas from pregnancies complicated by pre-eclampsia (PE). Fetal growth restriction (FGR) and PE often share a common pathophysiology; however, it is unknown whether increased placental HIF-1α occurs in FGR. We previously demonstrated that aberrant maternal inflammation in rats resulted in altered utero-placental perfusion and FGR, both of which were prevented by administration of the nitric oxide mimetic glyceryl trinitrate (GTN). Our aim here was to determine whether abnormal maternal inflammation causing FGR is linked to placental HIF-1α accumulation and whether GTN administration could prevent increases in placental HIF-1α.

Methods

Levels of inflammatory factors in maternal plasma were measured using a multiplex assay after an injection of low-dose lipopolysaccharide (LPS) to rats on gestational day (GD) 13.5. Following three additional daily LPS injections from GD14.5–16.5, GD17.5 placentas were harvested for HIF-1α immunolocalisation; serial sections were also stained for the hypoxia marker pimonidazole. A subset of rats received LPS injections along with GTN delivered continuously (25 μg/h via a transdermal patch) on GD12.5-GD17.5.

Results

Within two hours of LPS administration, levels of maternal pro-inflammatory cytokines were increased compared with saline-treated controls. GD17.5 placentas of growth-restricted fetuses exhibited increased HIF-1α accumulation; however, this did not correlate with pimonidazole staining for which no differences were observed between groups. Furthermore, the LPS-mediated increases in maternal inflammatory cytokine levels and placental HIF-1α accumulation did not occur in rats treated with GTN.

Discussion

Our results demonstrate that inflammation-induced FGR is associated with increased placental HIF-1α accumulation; however, expression of this transcription factor may not correlate with regions of hypoxia in late-gestation placentas. The GTN-mediated attenuation of placental HIF-1α accumulation in LPS-treated rats provides insight into the mechanism by which GTN improves inflammation-induced complications of pregnancy.

The Association between Periodontal Disease and Preterm Low Birthweight in Kosovo

OBJECTIVE

Periodontal diseases have a high prevalence worldwide. Existing evidence support the concept that gingivitis and periodontitis are potentially infectious and they present inflammatory reservoirs that can be threatening to the fetoplacental unit. The objective of this study was to compare the periodontal status between women with normal delivery and those with preterm low-birthweight delivery.

MATERIALS AND METHODS

This study included 200 postpartum women whose periodontal and obstetrical parameters were taken. The periodontal condition was assessed bedside according to the modified criteria established by Machtei, while the birthweight and gestational age were assessed according to the World Health Organization criteria.

RESULTS

Women with periodontitis are statistically at 3.2 times higher risk to deliver a child with low weight, and at 3.4 times higher risk to deliver preterm, compared to women without periodontitis. The women with preterm low-birthweight babies had deeper periodontal pockets (2.49mm ± 0.49mm) than women with normal delivery (2.26mm ± 0.49mm).

CONCLUSIONS

Periodontal disease in pregnant women with a reservoir of organisms and their products can be considered a risk factor for adverse pregnancy outcome.

Porphyromonas gingivalis induces IL-8 and IFN-gamma secretion and apoptosis in human extravillous trophoblast derived HTR8/SVneo cells via activation of ERK1/2 and p38 signaling pathways

INTRODUCTION

Preterm birth is a major cause for infant mortality and morbidity. A large number of studies have suggested a link between periodontal disease and preterm birth. The purpose of this study was to investigate the interaction between a periodontopathic bacterium Porphyromonas gingivalis and human extravillous trophoblast derived HTR8/SVneo cells.

METHODS

Production of cytokines in HTR8 cells was measured via ELISA. Annexin V/PI flow cytometry was performed to assess apoptosis. Protein expression was measured by western blot. Specific pharmacological inhibitors were used to inactivate relevant signaling pathways (p38 MAPK, SB203580; ERK1/2, U0126; JNK, SP600125; NF-κB, JSH-23) to determine their roles in inflammation and apoptosis.

RESULTS

HTR8 cells released significant amounts of IL-8 and IFN-γ during exposure to P. gingivalis. Meanwhile, the percentages of both early and late apoptotic cells increased significantly in response to P. gingivalis. The most significant effect on inflammation was found using SB203580 and U0126, followed by SP600125 and JSH-23. Moreover, U0126 and SB203580 both partially but significantly suppressed P. gingivalis-induced apoptosis, with a large effect by U0126. Additionally, both heat-killed P. gingivalis and P. gingivalis lipopolysaccharide significantly induced IL-8 production.

CONCLUSION

P. gingivalis induces inflammation and apoptosis in HTR8 cells, and we demonstrated for the first time that activation of ERK1/2 and p38 MAPK pathways participates in P. gingivalis-induced inflammation and apoptosis. The abnormal regulation of inflammation and apoptosis in human trophoblasts by P. gingivalis infection may give new insights into how maternal periodontal disease and periodontal pathogens might be linked to preterm birth.

Adverse pregnancy outcomes (APOs) and periodontal disease: pathogenic mechanisms

AIM

To evaluate the evidence on potential biological pathways underlying the possible association between periodontal disease (PD) and adverse pregnancy outcomes (APOs).

MATERIAL & METHODS

Human, experimental and in vitro studies were evaluated.

RESULTS

Periodontal pathogens/byproducts may reach the placenta and spread to the foetal circulation and amniotic fluid. Their presence in the foeto-placental compartment can stimulate a foetal immune/inflammatory response characterized by the production of IgM antibodies against the pathogens and the secretion of elevated levels of inflammatory mediators, which in turn may cause miscarriage or premature birth. Moreover, infection/inflammation may cause placental structural changes leading to pre-eclampsia and impaired nutrient transport causing low birthweight. Foetal exposure may also result in tissue damage, increasing the risk for perinatal mortality/morbidity. Finally, the elicited systemic inflammatory response may exacerbate local inflammatory responses at the foeto-placental unit and further increase the risk for APOs.

CONCLUSIONS

Further investigation is still necessary to fully translate the findings of basic research into clinical studies and practice. Understanding the systemic virulence potential of the individual's oral microbiome and immune response may be a distinctly different issue from categorizing the nature of the challenge using clinical signs of PD. Therefore, a more personalized targeted therapy could be a more predictive answer to the current "one-size-fits-all" interventions.

Adverse pregnancy outcomes (APOs) and periodontal disease: pathogenic mechanisms

AIM

To evaluate the evidence on potential biological pathways underlying the possible association between periodontal disease (PD) and adverse pregnancy outcomes (APOs).

MATERIAL & METHODS

Human, experimental and in vitro studies were evaluated.

RESULTS

Periodontal pathogens/byproducts may reach the placenta and spread to the foetal circulation and amniotic fluid. Their presence in the foeto-placental compartment can stimulate a foetal immune/inflammatory response characterized by the production of IgM antibodies against the pathogens and the secretion of elevated levels of inflammatory mediators, which in turn may cause miscarriage or premature birth. Moreover, infection/inflammation may cause placental structural changes leading to pre-eclampsia and impaired nutrient transport causing low birthweight. Foetal exposure may also result in tissue damage, increasing the risk for perinatal mortality/morbidity. Finally, the elicited systemic inflammatory response may exacerbate local inflammatory responses at the foeto-placental unit and further increase the risk for APOs.

CONCLUSIONS

Further investigation is still necessary to fully translate the findings of basic research into clinical studies and practice. Understanding the systemic virulence potential of the individual's oral microbiome and immune response may be a distinctly different issue from categorizing the nature of the challenge using clinical signs of PD. Therefore, a more personalized targeted therapy could be a more predictive answer to the current "one-size-fits-all" interventions.

Porphyromonas gingivalis within Placental Villous Mesenchyme and Umbilical Cord Stroma Is Associated with Adverse Pregnancy Outcome

Intrauterine presence of Porphyromonas gingivalis (Pg), a common oral pathobiont, is implicated in preterm birth. Our aim was to determine if the location of Pg within placental and/or umbilical cord sections was associated with a specific delivery diagnosis at preterm delivery (histologic chorioamnionitis, chorioamnionitis with funisitis, preeclampsia, and preeclampsia with HELLP-syndrome, small for gestational age). The prevalence and location of Pg within archived placental and umbilical cord specimens from preterm (25 to 32 weeks gestation) and term control cohorts were evaluated by immunofluorescent histology. Detection of Pg was performed blinded to pregnancy characteristics. Multivariate analyses were performed to evaluate independent effects of gestational age, being small for gestational age, specific preterm delivery diagnosis, antenatal steroids, and delivery mode, on the odds of having Pg in the preterm tissue. Within the preterm cohort, 49 of 97 (51%) placentas and 40 of 97 (41%) umbilical cord specimens were positive for Pg. Pg within the placenta was significantly associated with shorter gestation lengths (OR 0.63 (95%CI: 0.48–0.85; p = 0.002) per week) and delivery via caesarean section (OR 4.02 (95%CI: 1.15–14.04; p = 0.03), but not with histological chorioamnionitis or preeclampsia. However, the presence of Pg in the umbilical cord was significantly associated with preeclampsia: OR 6.73 (95%CI: 1.31–36.67; p = 0.02). In the term cohort, 2 of 35 (6%) placentas and no umbilical cord term specimens were positive for Pg. The location of Pg within the placenta was different between preterm and term groups in that Pg within the villous mesenchyme was only detected in the preterm cohort, whereas Pg associated with syncytiotrophoblasts was found in both preterm and term placentas. Taken together, our results suggest that the presence of Pg within the villous stroma or umbilical cord may be an important determinant in Pg-associated adverse pregnancy outcomes.

Sexual activity modulates shifts in TH1/TH2 cytokine profile across the menstrual cycle: an observational study

OBJECTIVE

To investigate if sexual activity moderated menstrual cycle-related shifts in cytokines associated with T-helper type 1 (TH1) cells (e.g., interferon [IFN] γ) and T-helper type 2 (TH2) cells (e.g., interleukin [IL] 4). Immune activity shifts across the menstrual cycle, with higher follicular-phase TH1-cell activity but higher luteal-phase TH2-cell activity. Little is known about how social behaviors alter TH1-TH2 ratios, despite evidence that psychosocial factors can influence immunity. Of particular interest is how sexual activity influences immune responses that may support conception, such as the TH1-TH2 balance.

DESIGN

Participants provided saliva samples at four time points (menstrual, follicular, ovulatory, and luteal phases), which were assayed by means of ELISA.

SETTING

Academic laboratory.

PARTICIPANT(S)

Thirty healthy premenopausal women (16 sexually abstinent, 14 sexually active) not taking hormonal or immunoactive medications.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Salivary E2, P, IFN-γ, and IL-4.

RESULT(S)

Sexually active, but not abstinent, women were significantly more likely to express TH2-like cytokine ratios (IFN-γ < IL-4) in the luteal phase than in other phases. Similarly, sexually active women had significantly higher P, and higher P-E2 ratios, in the luteal phase than did abstinent women. The P-E2 ratio mediated menstrual variations in cytokine ratios in sexually active women.

CONCLUSION(S)

These results support the hypothesis that shifts in immune response across the menstrual cycle may reflect tradeoffs between reproduction and immunity. These findings point to the need for further research on the interaction between sexual behavior, the menstrual cycle, and immune response.

Dental Infection of Porphyromonas gingivalis Induces Preterm Birth in Mice

BACKGROUND

Epidemiological studies have revealed a link between dental infection and preterm birth or low birth weight (PTB/LBW), however, the underlying mechanisms remain unclear. Progress in understanding the associated mechanisms has been limited in part by lack of an animal model for chronic infection-induced PTB/LBW, mimicking pregnancy under conditions of periodontitis. We aimed to establish a mouse model of chronic periodontitis in order to investigate the link between periodontitis and PTB/LBW.

METHODS

To establish chronic inflammation beginning with dental infection, we surgically opened mouse (female, 8 weeks old) 1st molar pulp chambers and directly infected with w83 strain Porphyromonas gingivalis (P.g.), a keystone periodontal pathogen. Mating was initiated at 6 wks post-infection, by which time dental granuloma tissue had developed and live P.g. was cultured from extracted tooth root, which serves as a persistent source of P.g. The gestational day (gd) and birth weight were recorded during for P.g.-infected and control mice, and serum and placental tissues were collected at gd 15 to evaluate the systemic and local conditions during pregnancy.

RESULTS

Dental infection with P.g. significantly increased circulating TNF-α (2.5-fold), IL-17 (2-fold), IL-6 (2-fold) and IL-1β (2-fold). The P.g.-infected group delivered at gd 18.25 vs. gd 20.45 in the non-infected control (NC) group (p < 0.01), and pups exhibited LBW compared to controls (p < 0.01). P.g. was localized to placental tissues by immunohistochemistry and PCR, and defects in placental tissues of P.g. infected mice included premature rupture of membrane, placental detachment, degenerative changes in trophoblasts and endothelial cells, including necrotic areas. P.g. infection caused significantly increased numbers of polymorphonuclear leukocytes (PMNLs) and macrophages in placental tissues, associated with increased local expression of pro-inflammatory mediators including TNF-α and COX-2. Further placental tissue damage was indicated in P.g. infected mice by decreased CD-31 in endothelial cells, increased expression of 8OHdG, an indicator of oxidative DNA damage, and cleaved caspase-3, a marker of apoptosis. In vitro, P.g. lipopolysaccharide significantly increased expression of COX-2, IL-8 and TNF-α, in HTR-8 trophoblasts in an NF-κB-dependent fashion.

CONCLUSIONS

Our novel mouse model supports previous epidemiological studies signifying dental infection as predisposing factor for PTB/LBW. We demonstrate PTB and LBW in infected mice, translocation of P.g to placental tissues, increased circulating and local pro-inflammatory markers, and the capability of P.g. LPS to directly induce cytokine production in trophoblasts, in vitro. These findings further underscore the importance of local and systemic infections and inflammation during pregnancy and suggest that prevention and/or elimination of dental infections such as marginal or periapical periodontitis before pregnancy may have a beneficial effect on PTB/LBW.

Of the bugs that shape us: maternal obesity, the gut microbiome, and long-term disease risk

Chronic disease risk is inextricably linked to our early-life environment, where maternal, fetal, and childhood factors predict disease risk later in life. Currently, maternal obesity is a key predictor of childhood obesity and metabolic complications in adulthood. Although the mechanisms are unclear, new and emerging evidence points to our microbiome, where the bacterial composition of the gut modulates the weight gain and altered metabolism that drives obesity. Over the course of pregnancy, maternal bacterial load increases, and gut bacterial diversity changes and is influenced by pre-pregnancy- and pregnancy-related obesity. Alterations in the bacterial composition of the mother have been shown to affect the development and function of the gastrointestinal tract of her offspring. How these microbial shifts influence the maternal-fetal-infant relationship is a topic of hot debate. This paper will review the evidence linking nutrition, maternal obesity, the maternal gut microbiome, and fetal gut development, bringing together clinical observations in humans and experimental data from targeted animal models.

M1/M2 macrophage polarity in normal and complicated pregnancy

Tissue macrophages play an important role in all stages of pregnancy, including uterine stromal remodeling (decidualization) before embryo implantation, parturition, and post-partum uterine involution. The activation state and function of utero-placental macrophages are largely dependent on the local tissue microenvironment. Thus, macrophages are involved in a variety of activities such as regulation of immune cell activities, placental cell invasion, angiogenesis, and tissue remodeling. Disruption of the uterine microenvironment, particularly during the early stages of pregnancy (decidualization, implantation, and placentation) can have profound effects on macrophage activity and subsequently impact pregnancy outcome. In this review, we will provide an overview of the temporal and spatial regulation of utero-placental macrophage activation during normal pregnancy in human beings and rodents with a focus on more recent findings. We will also discuss the role of M1/M2 dysregulation within the intrauterine environment during adverse pregnancy outcomes.

Salmonella enterica serovar Enteritidis enterocolitis during late stages of gestation induces an adverse pregnancy outcome in the murine model

Foodborne diseases caused by Salmonella enterica serovar Enteritidis (S. Enteritidis) are a significant health problem. Pregnancy, state of immunological tolerance, is a predisposing condition for the development of infections with intracellular pathogens. Salmonella species can cause pregnancy complications such as chorioamnionitis, transplacental fetal infection, pre term labor, abortions, neonatal and maternal septicemia. However, the specific mechanisms by which Salmonella infections trigger these alterations are not clear. In the present work, using a self-limiting enterocolitis murine model, we show that the ingestion of a low dose of S. Enteritidis at late stages of pregnancy (day 15 of gestation) is sufficient to induce massive maternal infection. We found that Salmonella infection leads to 40% of pre term delivery, 33% of abortion and fetal growth restriction. Placental dysfunction during S. Enteritidis enterocolitis was confirmed through cellular infiltration and hypoxia markers (MPO activity and COX-1 and COX-2 expression, respectively). Apoptosis in placental tissue due to Salmonella infection was also evident at day 18 of gestation when investigated by morphometric procedure, DNA fragmentation and Fas/FasL expression. Also, the expression of IFN-γ, TNF-α, IL-17 and IL-10 was up regulated in response to Salmonella not only in placenta, but also in amniotic fluid and maternal serum. Altogether, our results demonstrate that S. Enteritidis enterocolitis during late stages of gestation causes detrimental effect on pregnancy outcome.

Porphyromonas gingivalis, Treponema denticola and toll-like receptor 2 are associated with hypertensive disorders in placental tissue: a case-control study

AIM(S)

To explore the associations between the presence of periodontal pathogens and the expression of toll-like receptors (TLR-2 and TLR-4) in the placental tissue of patients with hypertensive disorders compared to the placentas of healthy normotensive patients.

MATERIAL AND METHODS

A case-control study was performed. From a cohort composed of 126 pregnant women, 33 normotensive healthy pregnant women were randomly selected, and 25 cases of patients with hypertensive disorders of pregnancy, including gestational hypertension and pre-eclampsia, were selected. Placental biopsy was obtained after aseptic placental collection at the time of delivery. All of the samples were processed and analysed for the detection of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Treponema denticola and Tannerella forsythia using the polymerase chain reaction (PCR) technique. Determination of the expressions of TLR-2 and TLR-4 was performed in samples of total purified protein isolated from placental tissues and analysed by ELISA. The data were assessed using descriptive statistics. The associations among variables were estimated through multiple logistic regression models and the Mann-Whitney test to evaluate the differences between the two groups.

RESULTS

A significant increase was observed in the expression of TLR-2 in the placentas of patients with hypertensive disorders (p = 0.04). Additionally, the multiple logistic regression models demonstrated an association between the presence of T. denticola and P. gingivalis in placental tissues and hypertensive disorders (OR: 9.39, p = 0.001, CI 95% 2.39-36.88 and OR: 7.59, p = 0.019, CI 95% 1.39-41.51, respectively).

CONCLUSIONS

In the present study, pregnant women with periodontal disease presented an association in the placental tissue between the presence of T. denticola and P. gingivalis and hypertensive disorders. Additionally, increased expression of TLR-2 was observed. However, further studies are required to determine the specific roles of periodontal pathogens and TLRs in the placental tissue of patients with pregnancy-related hypertensive disorders.

Perinatal periodontal disease reduces social behavior in male offspring

OBJECTIVE

Our objective was to verify whether prenatal maternal periodontitis is a risk factor for the development of central nervous system disorders in rats.

METHODS

Periodontitis was induced by placing a ligature around the upper and lower first molars in 9 female Wistar rats (experimental group); 9 rats were left unligated (control group). The maternal general activity in an open field was observed on gestational day (GD) 0, GD 4, and GD 14, and the maternal performance was assessed on the second day after birth. The pups' play behavior was assessed on postnatal day 30. The relative level of reelin was measured in the frontal cortex by real-time PCR analysis.

RESULTS

The results showed that, compared with the control group, (1) the general activity in female rats with periodontitis was decreased, (2) the maternal performance of these rats was not modified by periodontitis, (3) the play behavior of pups from dams with periodontitis was decreased, and (4) there were no differences in the frontal cortex reelin levels of pups from dams with periodontitis.

CONCLUSIONS

We conclude that pre- and postnatal periodontitis induces maternal sickness behavior and reduces the pups' play behavior without interference with frontal cortex reelin expression.