Periapical infection may affect birth outcomes via systemic inflammation

Maternal inflammatory and microbial drivers of low birthweight in low- and middle-income countries

BACKGROUND

Low birthweight (LBW) is when an infant is born too soon or too small, and it affects one in seven infants in low- and middle-income countries. LBW has a significant impact on short-term morbidity and mortality, and it impairs long-term health and human capital. Antenatal microbial and inflammatory exposure may contribute to LBW.

METHODS

Ovid-Medline, Embase and Cochrane databases were searched for English-language articles evaluating inflammatory, microbial or infective causes of LBW, small-for-gestational age, intra-uterine growth restriction or prematurity. Inclusion criteria were human studies including published data; conference abstracts and grey literature were excluded. A narrative synthesis of the literature was conducted.

RESULTS

Local infections may drive the underlying causes of LBW: for example, vaginitis and placental infection are associated with a greater risk of prematurity. Distal infection and inflammatory pathways are also associated with LBW, with an association between periodontitis and preterm delivery and environmental enteric dysfunction and reduced intra-uterine growth. Systemic maternal infections such as malaria and HIV are associated with LBW, even when infants are exposed to HIV but not infected. This latter association may be driven by chronic inflammation, co-infections and socio-economic confounders. Antimicrobial prophylaxis against other bacteria in pregnancy has shown minimal impact in most trials, though positive effects on birthweight have been found in some settings with a high infectious disease burden.

CONCLUSION

Maternal inflammatory and infective processes underlie LBW, and provide treatable pathways for interventions. However, an improved understanding of the mechanisms and pathways underlying LBW is needed, given the impact of LBW on life-course.

The influence of apical periodontitis on circulatory inflammatory mediators in peripheral blood: A prospective case-control study

AIM

To explore the influence of apical periodontitis (AP) on inflammatory markers in blood of otherwise healthy individuals and to depict the inflammatory profile of the healing after dental extraction.

METHODOLOGY

This is a prospective case-control intervention study, during which, individuals with a diagnosis of AP of one affected tooth were included, along with a control group matched for age and gender. A broad panel of blood inflammatory mediators was examined longitudinally in all subjects during six visits. In the case of the AP subjects, the tooth with AP was extracted at the third visit. Results were analysed by linear regression analyses and linear mixed-model analyses.

RESULTS

A total of 53 subjects were included in the study, 27 with AP and 26 without. Fifteen females and 12 males were included in the AP group, and 14 females and 12 males in the control group. At baseline, granulocyte colony-stimulating factor (p < .001), interleukin (IL)-1β (p = .03) and IL-4 (p = .01) were significantly lower in AP subjects than in controls. Comparison of the differences between baseline and the last visit, i.e. 3 months after the tooth extraction, showed a significant reduction in IL-10 (p = .03) and IL-12p70 (p = .01).

CONCLUSIONS

The immunologic profile of chronic AP in one tooth and its healing profile reveals a systemic low-grade inflammation through compensatory immunosuppression. A larger lesion or multiple lesions could disrupt the balance that the system is trying to maintain, resulting in loss of homeostasis.

Maternal leucocyte trajectory across pregnancy associated with offspring's growth

BACKGROUND

Leucocytes for individuals during pregnancy may form into different trajectory patterns. Since no studies have been conducted, we aim to examine the associations between leucocyte trajectory across pregnancy and offspring's birth outcomes and growth during the first 2 years.

METHODS

We conducted a retrospective study enrolled 1070 singleton pregnancies aged 21-46 years old between 2014 and 2018 in Huazhong University of Science and Technology Union Shenzhen Hospital, China. Leucocyte trajectories were modelled using growth mixture modelling and four trajectories were identified: moderate-increasing (n = 41), low-stable (n = 828), high-decreasing (n = 145) and low-increasing (n = 56).

RESULTS

Relative to the low-stable group, logistic regression analysis after adjusting for covariates indicated that the odds ratios of preterm were 3.06 (95% confidence interval (CI): 1.43-6.23) for moderate-increasing, 0.78 (95% CI: 0.38-1.47) for high-decreasing and 0.68 (95% CI: 0.23-1.61) for the low-increasing group, respectively. By using generalized estimating equation analysis, we observed that infants in the moderate-increasing and low-increasing group had -0.35 and -0.21 (P &lt; 0.01) lower head circumference z-score compared with the low-stable group, respectively. No significant association of leucocyte trajectory with other birth weight measures or anthropometric measure z-scores was found.

CONCLUSIONS

Changes in leucocytes across pregnancy affected the occurrence of preterm and offspring's head circumference during the first 2 years of life.

IMPACT

Previous researches on the association of leucocytes with pregnancy outcomes mainly focused on leucocytes in a specific trimester. No studies until now have been conducted to assess the influences of the leucocyte trajectories on the growth and development of infants. Changes in leucocytes across pregnancy affected the occurrence of preterm and offspring's head circumference during the first 2 years of life. Our study will positively contribute to the dialogue regarding the treatment of pregnancies with different levels of inflammation in each trimester to minimize adverse pregnancy outcomes and optimize brain growth.

Association between Endodontic Infection, Its Treatment and Systemic Health: A Narrative Review

The 'Focal Infection Era in Dentistry' in the late 19th and early 20th century resulted in widespread implementation of tooth extraction and limited the progress of endodontics. The theory proposed that bacteria and toxins entrapped in dentinal tubules could disseminate systemically to remote body parts, resulting in many types of degenerative systemic diseases. This theory was eventually refuted due to anecdotal evidence. However, lately there has been increased interest in investigating whether endodontic disease could have an impact on general health. There are reviews that have previously been carried out on this subject, but as new data have emerged since then, this review aims to appraise the available literature investigating the dynamic associations between apical periodontitis, endodontic treatment, and systemic health. The available evidence regarding focal infection theory, bacteraemia and inflammatory markers was appraised. The review also collated the available research arguing the associations of apical periodontitis with cardiovascular diseases, diabetes mellitus, adverse pregnancy outcome and autoimmune disorders, along with the effect of statins and immunomodulators on apical periodontitis prevalence and endodontic treatment prognosis. There is emerging evidence that bacteraemia and low-grade systemic inflammation associated with apical periodontitis may negatively impact systemic health, e.g., development of cardiovascular diseases, adverse pregnancy outcomes, and diabetic metabolic dyscontrol. However, there is limited information supporting the effect of diabetes mellitus or autoimmune disorders on the prevalence and prognosis post endodontic treatment. Furthermore, convincing evidence supports that successful root canal treatment has a beneficial impact on systemic health by reducing the inflammatory burden, thereby dismissing the misconceptions of focal infection theory. Although compelling evidence regarding the association between apical periodontitis and systemic health is present, further high-quality research is required to support and establish the benefits of endodontic treatment on systemic health.

The association between apical periodontitis and adverse pregnancy outcomes: a systematic review

BACKGROUND

The association between adverse pregnancy outcomes (APOs) and maternal apical periodontitis remains unclear as it has not been examined rigorously or reviewed systematically.

OBJECTIVE

To systematically review and critically evaluate the available evidence on the association of maternal apical periodontitis with several APOs.

METHODS

A literature search was conducted using the following electronic databases: Clarivate Analytics' Web of Science, Scopus, PubMed, and Cochrane Central Register of Controlled Trials (CENTRAL), from inception to 25 February 2021, with no language restrictions. Observational studies including longitudinal clinical trials, cohort, case-control and cross-sectional studies of prospective and retrospective design were included. Articles with duplicate or overlapping results, abstract-only papers, case reports, case series, animal studies and reviews were excluded. Two independent reviewers were involved in study selection, data extraction and appraising the included studies; disagreements were resolved by a third reviewer. The Newcastle-Ottawa Scale (NOS) and the adapted form of the NOS were used to assess the quality for case-control and cross-sectional studies, respectively.

RESULTS

Two case-control and one cross-sectional study were included in the current review. The included studies were published between 2015 and 2017, with a total of 1187 participating individuals with an approximate age range of 15 to 40 years. As the included studies reported different outcomes, the heterogeneity of data prevented a meta-analysis being undertaken. The overall quality of the evidence was 'Fair' for two out of three included studies, while one study was categorized as 'Good'.

DISCUSSION

Two out of three included primary studies had a substantial number of methodological inconsistencies and flaws, and therefore caution should be exercised in interpreting the results of this systematic review because several important covariates were not considered in the original investigations.

CONCLUSION

Based on a limited volume and 'Fair' and 'Good' quality of evidence, a positive association between maternal apical periodontitis and APOs was observed. However, more 'Good' quality clinical studies are needed to confirm the results of the current review.

FUNDING

None REGISTRATION: PROSPERO database (CRD42-2191987).

Can Probiotics Emerge as Effective Therapeutic Agents in Apical Periodontitis? A Review

Apical periodontitis (AP) is a biofilm-associated disease initiated by the invasion of dental pulp by microorganisms from the oral cavity. Eradication of intracanal microbial infection is an important goal of endodontic treatment, and this is typically accomplished by mechanical instrumentation and application of sodium hypochlorite and chlorhexidine. However, these agents are tissue-irritating at higher concentrations and cytotoxic. Certain probiotics have been found effective in controlling marginal periodontitis, as evidenced by reduction of pathogenic bacterial loads, gains in clinical attachment levels, and reduced bleeding on probing. In vitro studies have shown inhibitory activity of some probiotics against endodontic pathogens. Similarly, in vivo studies in rats have demonstrated a positive immuno-modulatory role of probiotics in AP, as manifested by decreased levels of proinflammatory markers and increased levels of anti-inflammatory markers. A role for probiotics in effecting a reduction of bone resorption has also been reported. This review provides an outline of current research into the probiotic management of AP, with a focus on understanding the mechanisms of their direct antagonistic activity against target pathogens and of their beneficial modulation of the immune system.

The controversial natural history of oral herpes simplex virus type 1 infection

The natural history of oral herpes simplex virus type 1 (HSV-1) infection in the immunocompetent host is complex and rich in controversial phenomena, namely the role of unapparent transmission in primary infection acquisition, the high frequency of asymptomatic primary and recurrent infections, the lack of immunogenicity of HSV-1 internalized in the soma (cell body) of the sensory neurons of the trigeminal ganglion, the lytic activity of HSV-1 in the soma of neurons that is inhibited in the sensory neurons of the trigeminal ganglion and often uncontrolled in the other neurons, the role of keratin in promoting the development of recurrence episodes in immunocompetent hosts, the virus-host Nash equilibrium, the paradoxical HSV-1-seronegative individuals who shed HSV-1 through saliva, the limited efficacy of anti-HSV vaccines, and why the oral route of infection is the least likely to produce severe complications. The natural history of oral HSV-1 infection is also a history of symbiosis between humans and virus that may switch from mutualism to parasitism and vice versa. This balance is typical of microorganisms that are highly coevolved with humans, and its knowledge is essential to oral healthcare providers to perform adequate diagnosis and provide proper individual-based HSV-1 infection therapy.

Apical Periodontitis Is Associated with Elevated Concentrations of Inflammatory Mediators in Peripheral Blood: A Systematic Review and Meta-analysis

INTRODUCTION

Apical periodontitis (AP), except for the local known consequences, may also be a systemic burden. Circulating inflammatory mediators that are released to sustain the AP lesion can in theory harm other bodily tissues. The aim of this systematic review was to summarize the existing evidence on the influence of AP on the peripheral blood levels of inflammatory mediators and markers of systemic stress.

METHODS

A search of MEDLINE-PubMed, Embase, and Cochrane was conducted up to and including February 2019 to identify studies in 5 different languages. The Newcastle-Ottawa Scale was used for quality assessment of the included studies.

RESULTS

Twelve of the 20 included studies were case-control studies, and 8 were intervention studies. The data of all the included studies were analyzed descriptively, whereas the data of 11 studies were available for meta-analyses. The study designs were heterogeneous. Nevertheless, the meta-analyses revealed statistically significant differences in C-reactive protein, interleukin 6, and asymmetric dimethylarginine levels between AP subjects and controls in peripheral blood. In addition, the concentration of C3 complement fragment in peripheral blood was significantly lower after the treatment and resolution of AP than before.

CONCLUSIONS

The existing literature indicates that AP adds on to systemic inflammation by elevating C-reactive protein, interleukin 6, asymmetric dimethylarginine, and C3 levels. In order to overcome the issue of large variation between study designs, future studies should have clear inclusion criteria, preferably larger cohorts, adequate follow-up of all subjects, and a thorough presentation of the data to enable further exploration of the possible burden of AP on general human health. Nevertheless, there is now stronger evidence that AP contributes to low-grade systemic inflammation.

The Impact of Infection in Pregnancy on Placental Vascular Development and Adverse Birth Outcomes

Healthy fetal development is dependent on nutrient and oxygen transfer via the placenta. Optimal growth and function of placental vasculature is therefore essential to support in utero development. Vasculogenesis, the de novo formation of blood vessels, and angiogenesis, the branching and remodeling of existing vasculature, mediate the development and maturation of placental villi, which form the materno-fetal interface. Several lines of evidence indicate that systemic maternal infection and consequent inflammation can disrupt placental vasculogenesis and angiogenesis. The resulting alterations in placental hemodynamics impact fetal growth and contribute to poor birth outcomes including preterm delivery, small-for-gestational age (SGA), stillbirth, and low birth weight (LBW). Furthermore, pathways involved in maternal immune activation and placental vascularization parallel those involved in normal fetal development, notably neurovascular development. Therefore, immune-mediated disruption of angiogenic pathways at the materno-fetal interface may also have long-term neurological consequences for offspring. Here, we review current literature evaluating the influence of maternal infection and immune activation at the materno-fetal interface and the subsequent impact on placental vascular function and birth outcome. Immunomodulatory pathways, including chemokines and cytokines released in response to maternal infection, interact closely with the principal pathways regulating placental vascular development, including the angiopoietin-Tie-2, vascular endothelial growth factor (VEGF), and placental growth factor (PlGF) pathways. A detailed mechanistic understanding of how maternal infections impact placental and fetal development is critical to the design of effective interventions to promote placental growth and function and thereby reduce adverse birth outcomes.

Placental exosome-mediated Bta-miR-499-Lin28B/let-7 axis regulates inflammatory bias during early pregnancy

Abnormal inflammatory bias in the maternal-fetal interface leads to reproductive failure in mammals. Placental exosomes are involved in maternal-fetal communication during pregnancy. However, whether the placenta or fetus is involved in regulating the balance of uterine local inflammation through exosomes remains unclear, and the mechanism must be further explored. Here we demonstrated that placenta-specific exosomes are abundant in the peripheral blood of dairy cows during early pregnancy and selectively load miRNAs, such as bta-miR-499. In vitro, placental exosome-derived bta-miR-499 inhibits the activation of NF-κB via the Lin28B/let-7 axis, thus repressing LPS-induced inflammation in bovine endometrial epithelial (BEND) cells. Subsequently, inhibition of mmu-miR-499 leads to an impaired balance of inflammation at the maternal-fetal interface in vivo, resulting in an increased risk of pregnancy failure due to placental loss and fetal growth restriction. Thus, our data demonstrate that placental exosomal miR-499 may be a critical immune regulator in the regulation of the inflammation balance at the maternal-fetal interface in the early gestation of dairy cows and other mammals.