FcγRIIB polymorphisms, periodontitis and preterm birth in Japanese pregnant women

Oral Anaerobic Microflora and Pregnancy Complication

Bacterial vaginosis and periodontal diseases share very similar pathogenesis. Each of these diseases occurs when healthy microbiome changes to predominately anaerobic bacterial flora. Bacterial vaginosis is proven factor for adverse pregnancy outcomes. In recent years it has been hypothesized that infection from distant sites of the fetoplacental unit may also elicit an inflammatory response in utero. Aim: The study is designed to determine whether the presence of specific oral anaerobic bacteria in subgingival sulcus of mother increase the risk of adverse obstetric outcomes. Material and Methods: Case-control study.  Control group: 50 patients who gave birth to neonate whit normal birth weight at term. Group cases: I group - 40 pregnant women who were hospitalized with signs of preterm labor. II - 20 pregnant women, who have an ultrasound diagnosis of fetal growth retardation. Sub-gingival microbiological paper-point swab was taken in all patients. Results: The total number of isolated oral anaerobic bacteria was statistically significantly higher in the cases group compared to control group p <0.01. In our study, pregnant women who tested positive for Porphyrmonas gingivalis for 6.65 times were more likely to have preterm labor compare with pregnant women with negative oral swabs (95.0% CI: 1.38-32.11 / p <0.05), and for 2,79 times more likely to have fetus with intrauterine growth restriction (95.0% CI: 1.10-7.91 / p <0.05 Conclusions: The study confirmed the hypothesis of a statistically significant association between oral anaerobic infection and adverse pregnancy outcomes. In the future, more studies are needed to investigate the role of the microbial load, maternal immune response, pathophysiological pathway that leads to negative pregnancy outcome.  

Spontaneous preterm birth and single nucleotide gene polymorphisms: a recent update

Background

Preterm birth (PTB), birth at <37 weeks of gestation, is a significant global public health problem. World-wide, about 15 million babies are born preterm each year resulting in more than a million deaths of children. Preterm neonates are more prone to problems and need intensive care hospitalization. Health issues may persist through early adulthood and even be carried on to the next generation. Majority (70 %) of PTBs are spontaneous with about a half without any apparent cause and the other half associated with a number of risk factors. Genetic factors are one of the significant risks for PTB. The focus of this review is on single nucleotide gene polymorphisms (SNPs) that are reported to be associated with PTB.

Results

A comprehensive evaluation of studies on SNPs known to confer potential risk of PTB was done by performing a targeted PubMed search for the years 2007–2015 and systematically reviewing all relevant studies. Evaluation of 92 studies identified 119 candidate genes with SNPs that had potential association with PTB. The genes were associated with functions of a wide spectrum of tissue and cell types such as endocrine, tissue remodeling, vascular, metabolic, and immune and inflammatory systems.

Conclusions

A number of potential functional candidate gene variants have been reported that predispose women for PTB. Understanding the complex genomic landscape of PTB needs high-throughput genome sequencing methods such as whole-exome sequencing and whole-genome sequencing approaches that will significantly enhance the understanding of PTB. Identification of high risk women, avoidance of possible risk factors, and provision of personalized health care are important to manage PTB.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-3089-0) contains supplementary material, which is available to authorized users.

Epidemiology of association between maternal periodontal disease and adverse pregnancy outcomes--systematic review

BACKGROUND AND OBJECTIVES

There is still debate regarding potential relationships between maternal periodontitis during pregnancy and adverse pregnancy outcomes. The aim of this systematic review was to synthesize the available epidemiological evidence on this association.

DATA SOURCES

Combined electronic and hand search of MEDLINE, EMBASE, WEB OF SCIENCE and Cochrane Central Register databases.

STUDY ELIGIBILITY CRITERIA

Original publications reporting data from cross-sectional, case-control or prospective cohort epidemiological studies on the association between periodontal status and preterm birth, low birthweight (LBW) or preeclampsia. The search was not limited to publications in English. All selected studies provided data based on professional assessments of periodontal status, and outcome variables, including preterm birth (<37 weeks gestation), LBW (<2500 g), gestational age, small for gestational age, birthweight, pregnancy loss or miscarriage, or pre-eclampsia.

PARTICIPANTS

Pregnant women with or without periodontal disease, and with or without adverse pregnancy outcomes, assessed either during pregnancy or postpartum. No intervention studies were included. Study appraisal and synthesis methods - Publications were assessed based on predefined screening criteria including type of periodontal assessment, consistency in the timing of the periodontal assessment with respect to gestational age, examiner masking and consideration of additional exposures and confounders.

RESULTS

Maternal periodontitis is modestly but significantly associated with LBW and preterm birth, but the use of a categorical or a continuous exposure definition of periodontitis appears to impact the findings: Although significant associations emerge from case-control and cross-sectional studies using periodontitis "case definitions," these were substantially attenuated in studies assessing periodontitis as a continuous variable. Data from prospective studies followed a similar pattern, but associations were generally weaker. Maternal periodontitis was significantly associated with pre-eclampsia.

LIMITATIONS

There is a high degree of variability in study populations, recruitment and assessment, as well as differences in how data are recorded and handled. As a result, studies included in meta-analyses show a high degree of heterogeneity.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Maternal periodontitis is modestly but independently associated with adverse pregnancy outcomes, but the findings are impacted by periodontitis case definitions. It is suggested that future studies employ both continuous and categorical assessments of periodontal status. Further use of the composite outcome preterm LBW is not encouraged.

Association of the FcγRIIB-nt645+25A/G polymorphism with the expression level of the FcγRIIb receptor, the antibody response to Porphyromonas gingivalis and the severity of periodontitis

BACKGROUND AND OBJECTIVE

Human FcγRIIb is an immunoglobulin G (IgG) receptor that inhibits the activation of B lymphocytes through cross-linking with the B-cell receptor via immune complexes. This function acts as a negative regulator of antibody production. Our previous studies have demonstrated the gene polymorphisms in FcγRIIb to be associated with periodontitis. In this study, we presented a polymorphism--FcγRIIB-nt645+25A/G (rs2125685)--in intron 4 and analyzed its functional relevance to periodontitis. We examined whether the FcγRIIB-nt645+25A/G polymorphism is associated with periodontal parameters, the IgG response to the periodontopathic bacterium Porphyromonas gingivalis and/or the expression level of FcγRIIb on peripheral B lymphocytes.

MATERIAL AND METHODS

Thirty-two patients with chronic periodontitis were genotyped with nested PCR and by direct sequencing of genome DNA. The levels of serum IgG and of specific IgG subclasses for P. gingivalis sonicate and for the recombinant 40-kDa outer membrane protein (OMP) were determined. The expression levels of FcγRIIb on peripheral B lymphocytes from 19 healthy donors were measured by flow cytometry.

RESULTS

Patients with the FcγRIIB-nt645+25AA genotype showed significantly higher mean clinical attachment levels compared to patients with the FcγRIIB-nt645+25GG genotype (p = 0.003) and a significantly lower IgG response to P. gingivalis sonicate and to the 40-kDa OMP. The expression levels of FcγRIIb protein on the cell surface in peripheral B lymphocytes were higher in healthy donors with the FcγRIIB-nt645+25AA genotype than in those with the FcγRIIB-nt645+25GG genotype (p = 0.03).

CONCLUSION

The higher expression levels of FcγRIIb in subjects with the FcγRIIB-nt645+25AA genotype may induce a lower level of production of IgG against P. gingivalis and therefore more severe periodontitis.