Fibronectin levels of unstimulated saliva from naval recruits with and without chronic inflammatory periodontal disease

Quantitative evaluation of the vasculature and fibronectin localization in gingival connective tissue of smokers and non-smokers

BACKGROUND

It has been shown that tobacco is a significant risk factor for periodontal disease. The reason for decreased gingival bleeding in smokers is not known. The aim of the present study was to demonstrate the localization of fibronectin in the extracellular matrix of the inflamed gingiva of smokers and non-smokers and to evaluate the chronic effect of smoking on the gingival microvessel number (NVES) and vascular surface density (VSD).

METHODS

Seventy-four (74) adult patients with periodontitis were included in this investigation. Of these patients, 38 were smokers and 36 were non-smokers. Probing depths (PD), papillary bleeding index (PBI) of both groups, and the smoking habits of the smokers were recorded. Biopsy specimens obtained during periodontal surgery were prepared to evaluate fibronectin distribution and to quantitate the vasculature.

RESULTS

The mean VSD values of smokers and non-smokers were 6.721 +/- 1.845 and 5.721 +/- 3.118 (mean +/- SD), and the mean NVES of smokers and non-smokers was 31.582 +/- 11.810 and 30.145 +/- 15.442, respectively. The difference between the mean PD and PBI values of the 2 groups was not statistically significant. The location of the biopsy specimen, whether in the anterior or posterior area of the mouth, did not lead to any statistically significant differences between the groups. In addition, the number of years smoked and the tobacco brand used did not result in statistically significant differences. The most intense staining of fibronectin was observed beneath the epithelium around the blood vessels of the uppermost region of the connective tissue, showing a fibrillar and diffuse distribution; however, there was no significant difference between smokers and non-smokers.

CONCLUSION

The results of the present study indicate that smoking does not affect the vascular surface density, number of vessels per mm2 stroma, or fibronectin distribution in subepithelial gingival connective tissue.

Fibronectin levels in stimulated whole-saliva and their relationship with cariogenic oral bacteria

AIM

Fibronectin is a multifunctional glycoprotein that plays a fundamental role in mechanism of cellular union and in bacterial adhesion in the oral cavity. The aim of this study was to test the clinical relationship between fibronectin concentration in stimulated whole-saliva and the number of Mutans streptococci bacteria.

PARTICIPANTS

The sample consisted of 167 children aged 12 years.

METHODS

Saliva samples were collected from the subjects. Bacterial quantification was carried out using a semiquantitative method (Dentocult SM, Vivadent). Fibronectin was measured by the ELISA method with modifications.

RESULTS

An inverse clinical relation was found between the levels of soluble fibronectin and the number of SM colony forming units.

CONCLUSIONS

Bacterial counts sufficiently high to destroy the protein films increase bacterial binding to dental surfaces, thereby contributing to the regulation of bacterial plaque composition and its pathogenic potential. This capacity of glycoproteins to reduce the adhesion of microorganisms to the oral tissues and favour macrophage action supports the hypothesis that such proteins contribute to the first line of immune defence together with secretory antibodies.

Streptococcus pyogenes serotype M1 encodes multiple pathways for entry into human epithelial cells

The ability of a serotype M1 strain of Streptococcus pyogenes to efficiently invade A549 human lung epithelial cells was previously shown to be dependent on bacterial exposure to human or bovine serum proteins or synthetic peptides containing the sequence RGD. In this study, stimulation by invasion agonists was determined to be dependent on expression of the streptococcal cell surface protein, M1. Fetal bovine serum (FBS), fibronectin (Fn), the extracellular matrix protein laminin (Lm), and RGD-containing peptides were tested for their abilities to promote epithelial cell invasion and adherence by isogenic M1(+) and M1(-) strains of S. pyogenes. In the absence of an agonist, invasion and adherence were comparable for the two bacterial strains. FBS, Fn, and Lm stimulated invasion of the M1(+) strain as much as 70-fold but failed to significantly affect invasion by the M1(-) mutant. Adherence of the wild-type strain was stimulated by these same agonists. Epithelial cell adherence by the M1(-) strain, however, was unaffected by the presence of Fn or Lm. Several RGD-containing peptides were found to promote invasion independently of M1 expression. Binding of 125I-Fn was reduced 88% by the M1(-) mutation and Fn was found to bind purified M1 protein, suggesting that Fn mediates invasion by direct binding to M1. To determine if host integrins might be involved in internalization of streptococci, several anti-integrin monoclonal antibodies (MAbs) were tested for their abilities to inhibit invasion. Antibody directed against integrin beta1 inhibited FBS-, Fn-, and Lm-mediated invasion but did not abrogate RGD-peptide-stimulated invasion. MAb directed against the epithelial cell Fn receptor, integrin alpha5beta1, inhibited Fn and FBS-mediated invasion but did not specifically inhibit Lm-mediated invasion. These results indicate that S. pyogenes has evolved multiple mechanisms for invasion of eukaryotic cells, at least two of which involve interactions between M1 protein, host integrins, and integrin ligands.

Immunohistochemical distribution of fibronectin in the mucosa with chronic sinusitis

The distribution of fibronectin (FN) in operative specimens of maxillary sinus mucosa from 35 patients with chronic sinusitis was examined immunohistochemically. Mouse monoclonal antibody to human FN was used for the peroxidase-antiperoxidase staining technique. FN was found in most of the serous cells and in some (about 10%) of the mucous cells in the nasal glands, and also in the nasal fluid in the lumina. It was not found elsewhere, be it in the epithelial cells, the basement membrane, or the interstitial tissue, except in two patients. These results suggest that FN is produced in the nasal glands and secreted into the nasal fluid in the maxillary sinus in chronic sinusitis.