Antibody responses to Porphyromonas gingivalis outer membrane protein in the first trimester

Porphyromonas gingivalis outside the oral cavity

Porphyromonas gingivalis, a Gram-negative anaerobic bacillus present in periodontal disease, is considered one of the major pathogens in periodontitis. A literature search for English original studies, case series and review articles published up to December 2019 was performed using the MEDLINE, PubMed and GoogleScholar databases, with the search terms "Porphyromonas gingivalis" AND the potentially associated condition or systemic disease Abstracts and full text articles were used to make a review of published research literature on P. gingivalis outside the oral cavity. The main points of interest of this narrative review were: (i) a potential direct action of the bacterium and not the systemic effects of the inflammatory acute-phase response induced by the periodontitis, (ii) the presence of the bacterium (viable or not) in the organ, or (iii) the presence of its virulence factors. Virulence factors (gingipains, capsule, fimbriae, hemagglutinins, lipopolysaccharide, hemolysin, iron uptake transporters, toxic outer membrane blebs/vesicles, and DNA) associated with P. gingivalis can deregulate certain functions in humans, particularly host immune systems, and cause various local and systemic pathologies. The most recent studies linking P. gingivalis to systemic diseases were discussed, remembering particularly the molecular mechanisms involved in different infections, including cerebral, cardiovascular, pulmonary, bone, digestive and peri-natal infections. Recent involvement of P. gingivalis in neurological diseases has been demonstrated. P. gingivalis modulates cellular homeostasis and increases markers of inflammation. It is also a factor in the oxidative stress involved in beta-amyloid production.

The relationship between the anti-Porphyromonas gingivalis immunoglobulin G subclass antibody and small for gestational age delivery: a longitudinal study in pregnant Japanese women

BACKGROUND

Maternal serum IgG antibody against Porphyromonas gingivalis is an indicator of both periodontitis and adverse pregnancy outcomes. This study aims to evaluate the anti-P. gingivalis IgG and IgG subclasses1-4 in threatened preterm labour (TPL) patients and their association with small for gestational age (SGA).

METHODS

Serum, saliva and subgingival plaque samples were collected from 47 TPL patients compared with 48 healthy pregnant women. The amount of P. gingivalis was measured in saliva and plaque using real-time polymerase chain reaction. The serum anti-P. gingivalis IgG titre and anti-P. gingivalis subclasses IgG 1-4 concentration were measured using enzyme-linked immunosorbent assay.

RESULTS

The amount of anti-P. gingivalis IgG-1 was significantly lower in the TPL group than in the healthy group. Fourteen subjects delivered SGA infants in the TPL group. The pocket probing depth (PPD), clinical attachment loss, PPD ≥ 5 mm%, amount of P. gingivalis in plaque, anti-P. gingivalis IgG and anti-P. gingivalis IgG-4 were significantly higher in the TPL-SGA group than in the TPL-normal weight group. Moreover, logistic regression analysis revealed the detection frequency of P. gingivalis in plaque and placenta weight were significantly correlated with SGA in TPL. In the receiver operating characteristic curve analysis, an amount of P. gingivalis in plaque ≥ 86.45 copies showed a sensitivity of 0.786 and a specificity of 0.727 (AUC 0.792) for predicting SGA in TPL.

CONCLUSION

Lower anti-P. gingivalis IgG-1 amounts are related to TPL, while higher anti-P. gingivalis IgG and IgG-4 are related with SGA in TPL. Further, greater colonisation of P. gingivalis in plaque might increase the risk of SGA and can be useful in prediction of SGA in TPL.

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.

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.

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.

Peroxisome proliferator-activated receptor gamma polymorphism and periodontitis in pregnant Japanese women

BACKGROUND

Recent studies suggest an association between maternal periodontitis and preterm birth, although the association remains controversial. It was suggested that mechanisms such as a genetic predisposition for a hyperinflammatory response cause periodontitis and preterm births. Peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear hormone receptor and ligand-dependent transcription factor. PPARgamma inhibits the transcriptional activity of the genes that produce proinflammatory mediators and repress periodontitis. Recently, a common polymorphism, proline(PRO)-to-alanine(ALA) mutation at codon12 in exonB (Pro12Ala: rs 1801282) PPARgamma, was reported to reduce the ability to transactivate responsive promoters. In this study, we tested whether the PPARgammaPro12Ala polymorphism was associated with maternal periodontitis and/or preterm birth.

METHODS

Genomic DNA was isolated from the venous blood of pregnant Japanese women (term birth: n = 72; preterm birth: n = 58). The PPARgammaPro12Ala genotype was determined by polymerase chain reaction (PCR)-restriction fragment length polymorphism. Within 5 days after labor, clinical periodontal parameters were evaluated, and periodontopathic bacteria from the subgingival plaque were detected by species-specific PCR.

RESULTS

The mean clinical attachment level (P = 0.012), mean probing depth (P = 0.031), mean gingival index (P = 0.037), and percentages of sites with bleeding on probing (P = 0.041) in women with the PPARgammaPro12Ala genotype were significantly higher than in women with the PPARgammaPro12Pro genotype. However, there was no association between preterm birth and periodontitis.

CONCLUSION

We suggest that the PPARgammaPro12Ala polymorphism may represent a genetic susceptibility factor for the clinical measurements of periodontitis in a limited number of pregnant Japanese women, but it probably cannot influence the relationship between periodontitis and preterm birth.