Effect of periodontal therapy on specific antibody responses to suspected periodontopathogens

The effects of clinically successful periodontal therapy were studied in juvenile periodontitis (JP) and rapidly progressive periodontitis (RP) patients and compared with periodontally healthy subjects (HS). Serum samples were obtained in 35 HS prior to the study and in 12 of these subjects 3-4 years later. Serum samples were obtained from 50 JP patients initially, 9 subjects immediately following surgical therapy and 29 of these subjects 3-4 years later. RP patients provided 46 initial serum samples, 9 following therapy and 27 samples 3-4 years later. Antibody levels were determined utilizing a standardized enzyme-linked immunosorbent assay with Bacteroides gingivalis, B. ochracea, Fusobacterium nucleatum and Actinobacillus actinomycetemcomitans serving as antigens. The JP patients showed an initial rise in antibody levels immediately following therapy followed by a significant decrease in antibody levels 3 to 4 years later. The RP patients did not show an early change in antibody levels but by 3 to 4 years post-therapy, antibody levels had significantly decreased. However, during this study, the antibody levels of JP and RP patients remained significantly higher when compared with HS patients.     

DNA probe detection of periodontopathogens in advanced periodontitis

Species-specific DNA probes were used to determine the presence of Actinobacillus actinomycetemcomitans (A.a.), Porphyromonas (Bacteroides) gingivalis, Prevotella intermedia, Treponema denticola. Eikenella corrodens, Fusobacterium nucleatum , and Wolinella recta in subgingival plaque from deep pockets/sites of patients with advanced periodontitis. The subjects were 20 patients with severe adult periodontitis, 13 men and 7 women (mean age 45.6 ± 6.7 yr). For each subject, 9–10 subgingival sites with the deepest probing depths from each quadrant were sampled by the paper point method, a total of 198 sites, with mean probing depth 7.2 ± 1.6 mm and clinical attachment level 9.5 ± 2.7 mm. A.a . was present in at least one site in 75% of the subjects; P. gingivalis was found in 95%; P. intermedia and W. recta were found in 90%, respectively; and T. denticola, E. corrodens , and F. nucleatum were found in all subjects. In the 198 samples, A.a . was detected in 25.8%, P. gingivalis in 51.5%, P. intermedia in 64.1%, T. denticola in 60.6%, E. corrodens in 72.9%, F. nucleatum in 74.7%, and W. recta in 65.7%. The predominant combination was the simultaneous presence of P. intermedia, T. denticola, E. corrodens, F. nucleatum , and W. recta in 89.5% of the subjects and 46.8% of the sites. Of these sites, 51.1% showed the combined presence of P. gingivalis and 28.4% that of both A.a . and P. gingivalis . None of the seven bacteria could be detected in 14.4% of the total sites sampled. The present study indicates that severe destructive adult periodontitis is a multibacterial infection and that certain combinations of periodontopathogens seein to be important in the pathogenesis of the disease.     

Gingipain‐dependent augmentation by Porphyromonas gingivalis of phagocytosis of Tannerella forsythia

In the pathogenesis of periodontitis, Porphyromonas gingivalis plays a role as a keystone pathogen that manipulates host immune responses leading to dysbiotic oral microbial communities. Arg‐gingipains (RgpA and RgpB) and Lys‐gingipain (Kgp) are responsible for the majority of bacterial proteolytic activity and play essential roles in bacterial virulence. Therefore, gingipains are often considered as therapeutic targets. This study investigated the role of gingipains in the modulation by P. gingivalis of phagocytosis of Tannerella forsythia by macrophages. Phagocytosis of T. forsythia was significantly enhanced by coinfection with P. gingivalis in a multiplicity of infection‐dependent and gingipain‐dependent manner. Mutation of either Kgp or Rgp in the coinfecting P. gingivalis resulted in attenuated enhancement of T. forsythia phagocytosis. Inhibition of coaggregation between the two bacterial species reduced phagocytosis of T. forsythia in mixed infection, and this coaggregation was dependent on gingipains. Inhibition of gingipain protease activities in coinfecting P. gingivalis abated the coaggregation and the enhancement of T. forsythia phagocytosis. However, the direct effect of protease activities of gingipains on T. forsythia seemed to be minimal. Although most of the phagocytosed T. forsythia were cleared in infected macrophages, more T. forsythia remained in cells coinfected with gingipain‐expressing P. gingivalis than in cells coinfected with the gingipain‐null mutant or infected only with T. forsythia at 24 and 48 h post‐infection. Collectively, these results suggest that P. gingivalis, mainly via its gingipains, alters the clearance of T. forsythia, and provide some insights into the role of P. gingivalis as a keystone pathogen.     

Inflammation, heat shock proteins and periodontal pathogens in atherosclerosis: an immunohistologic study

Background:  Inflammation is a significant component of atherosclerosis lesions. Bacteria, including periodontopathogens, have been demonstrated in atherosclerotic plaques and cross-reactivity of the immune response to bacterial GroEL with human heat shock protein 60 has been suggested as a link between infections and atherosclerosis.
Methods:  In this study, the nature of the inflammatory infiltrate and the presence of human heat shock protein 60 and GroEL were examined in 31 carotid endarterectomy specimens. Additionally, monoclonal antibodies were used to detect the presence of six bacteria, including those implicated in periodontal disease.
Results:  The inflammatory cell infiltrate of the lesions was dominated by CD14⁺ macrophages and CD4⁺ T cells. Most cells of the infiltrate as well as the endothelium were HLA-DR⁺, indicating activation; however, there was an absence of CD25 expression, demonstrating that the activated T cells were not proliferating. Few CD1a⁺ and CD83⁺ cells were noted. Human heat shock protein 60 expression was evident on endothelial cells and cells with the appearance of smooth muscle cells and lymphocytes. GroEL and bacteria were detected within intimal cells. Chlamydia pneumoniae, Porphyromonas gingivalis, Fusobacterium nucleatum, Tannerella forsythia, Prevotella intermedia , and Actinobacillus actinomycetemcomitans were found in 21%, 52%, 34%, 34%, 41%, and 17% of arteries, respectively.
Conclusion:  These results give evidence for a specific immune response associated with atherosclerosis. Whether bacteria initiate the observed inflammation in atherosclerotic lesions is not clear; however, the present study shows that maintenance of inflammation may be enhanced by the presence of periodontopathic bacteria.     

Strong and persistent microbial and inflammatory stimuli overcome the genetic predisposition to higher matrix metalloproteinase-1 (MMP-1) expression: a mechanistic explanation for the lack of association of MMP1-1607 single-nucleotide polymorphism genotypes with MMP-1 expression in chronic periodontitis lesions

Aims: Our objective was to evaluate the association between the MMP1-1607 single-nucleotide polymorphism (SNP), periodontopathogens and inflammatory cytokines with matrix metalloproteinase-1 (MMP-1) mRNA levels in vitro and in vivo.
Materials and Methods: This study investigated the influence of genetic ( MMP1-1607 SNP), microbial ( Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, Actinobacillus actinomycetemcomitans ) and inflammatory [tumour necrosis factor- α (TNF- α ) and interleukin-1 β (IL-1 β )] factors on the determination of MMP-1 mRNA levels in periodontal tissues of non-smoker chronic periodontitis (CP, N =178) and control (C, N =190) groups. The effects of single and repeated lipopolysaccharide (LPS) and inflammatory cytokine stimulation of macrophages with distinct MMP1-1607 SNP genotypes were also investigated.
Results: In healthy tissues, the MMP1-1607 2G allele was associated with higher MMP-1 levels while in CP MMP-1 levels were associated with the presence and load of periodontopathogens, and also with TNF- α and IL-1 β expression irrespective of the MMP1-1607 genotype. In vitro data demonstrate that in 2G macrophages low- and intermediate-dose LPS and TNF- α +IL-1 β stimulation was associated with increased MMP-1 expression, while strong and repeated stimulation resulted in higher MMP-1 levels irrespective of the MMP1-1607 genotype.
Conclusion: Our data demonstrate a limited role for MMP1-1607 SNP in periodontitis, where the extensive chronic antigenic challenge exposure overcomes the genetic control and plays a major role in the determination of MMP-1 expression.     

Coaggregation of Streptococcus salivarius with periodontopathogens: evidence for involvement of fimbriae in the interaction with Prevotella intermedia

Streptococcus salivarius is divided into two serological subgroups that carry either fibrils or fimbriae. Although fimbriae have been observed on up to 50% of S. salivarius strains in the human oral cavity, no function has yet been assigned to them. To determine whether S. salivarius fimbriae have a role in adhesion, we examined the ability of S. salivarius to coaggregate with selected microorganisms involved in periodontal diseases. Our results show that S. salivarius coaggregated with Fusobacterium nucleatum, Porphyromonas gingivalis, and Prevotella intermedia. However, only fimbriated S. salivarius cells were able to coaggregate with P. intermedia, suggesting a specific role for these structures in the interaction. Heat treatment, sensitivity to sugars, amino acids, and EDTA, as well as protease treatment were also used to further characterize coaggregation between S. salivarius and periodontopathogens.     

Effect of smoking and periodontal treatment on the subgingival microflora

BACKGROUND: The effect of smoking on the prevalence of periodontal pathogens after periodontal treatment is still not clear. Some studies found no effect of the smoking status on the prevalence of periodontal pathogens after therapy, whereas others did. The aim of this retrospective study was to investigate the influence of smoking on the treatment of periodontitis and the composition of the subgingival microflora. METHOD: The study included 59 periodontitis patients (mean age 41.5 years): 30 smokers and 29 nonsmokers. The treatment consisted of initial periodontal therapy and, if necessary, surgery and/or antibiotics. Clinical and microbiological data were obtained before and after treatment at the deepest site in each quadrant. A pooled sample was analysed for the presence of Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotalla intermedia (Pi), Bacteroides forsythus (Bf), Fusobacterium nucleatum (Fn) and Peptostreptococcus micros (Pm). RESULTS: For smokers and nonsmokers a significant improvement of the clinical condition was found after treatment. A decrease could be assessed for bleeding on probing (smokers: 0.46; nonsmokers: 0.52) and probing pocket depth (PPD) (smokers: 1.64 mm; nonsmokers: 2.09 mm). Furthermore, both groups showed gain of attachment (smokers: 0.68 mm; nonsmokers: 1.46 mm). No significant difference in bleeding on probing and PPD reduction was found between smokers and nonsmokers. In contrast, nonsmokers showed significantly more gain of attachment than smokers. The microbiological results revealed no differences in the prevalence of the various bacteria between smokers and nonsmokers before treatment. After treatment in nonsmokers, a significant decrease was found in the prevalence of Aa (11-3), Pg (17-7), Pi (27-11), Bf (27-11), Fn (28-20) and Pm (27-17). In smokers, a significant decrease could be shown only for the prevalence of Pg (15-5). CONCLUSIONS: Nonsmokers showed more gain of attachment and a greater decrease in the prevalence of periodontal bacteria as compared to smokers. The phenomenon that among smokers, more patients remain culture positive for periodontal pathogens after therapy, may contribute to the often observed unfavourable treatment results in smoker periodontitis patients.     

Longitudinal evaluation of the development of periodontal destruction in spouses

Abstract The aim of the present investigation was to study longitudinally the periodontal condition of married couples. The data are derived from a longitudinal study in a young population living in a remote village in Indonesia and showing a relatively high prevalence of periodontal destruction. In 23 married couples, clinical measurements were carried out in 1987 and 1994. During the latter examination, a pooled gingival sample was obtained for microbiological evaluation. In 1994. the mean age of the group was 29.1 years and the couples were married for on the average 10 years. In each couple, the partner showing in 1994 the highest score for mean loss of attachment (LA) was classified as the diseased proband and the other partner as the spouse. Evaluation of the clinical data showed that: (11 the diseased probands already had in 1987 a worse periodontal condition compared to that of the spouses; (2) in both groups the mean LA increased during the 7-year period;13) the difference in mean LA between diseased probands and spouses increased between 1987 and 1994. The microbiological evaluation revealed a relatively high prevalence of Actinobadllus actinomycetemcomitans (50%). Porphyromonas gingivalis (67%) and Prevotella intermedia 61%. Analysis showed no differences in microbiota between diseased probands and spouses. The 23 Actinobadllus actinomycetemcomitans positive subjects included 2 positive couples. Furthermore, the 31 Porphyrormmas gingivalis and 28 Prevotella intermedia positive subjects included 9 and 7 positive couples respectively. In conclusion, 10 years of cohabitation showed no influence on the periodontal condition of the spouses.