Probiotic intervention influences the salivary levels of Matrix Metalloproteinase (MMP)-9 and Tissue Inhibitor of metalloproteinases (TIMP)-1 in healthy adults.

OBJECTIVE: To study the effect of orally administered Bifidobacterium animalis subsp. lactis BB-12 and Lactobacillus rhamnosus GG on the salivary levels of Matrix Metalloproteinases (MMP)-8, MMP-9 and of Tissue Inhibitor of Metalloproteinases (TIMP)-1 in healthy adults. Furthermore, the correlations between MMP-8, MMP-9 and TIMP-1 and plaque and gingival indices, salivary mutans streptococci and lactobacilli counts, and stimulated saliva secretion rate were analysed. DESIGN: The salivary samples originated from a randomized controlled trial where healthy student volunteers consumed probiotic or placebo lozenges twice a day for four weeks. The saliva samples were collected and clinical parameters measured at the baseline and at the end of the original study. For this study, the salivary levels of MMP-8, MMP-9 and TIMP-1 were analysed with immunofluorometric assay (IFMA) and enzyme-linked immunosorbent assay (ELISA). RESULTS: In the probiotic group (n=29), salivary MMP-9 levels increased (p<0.01) and TIMP-1 levels decreased (p<0.01) significantly during the intervention. Furthermore, MMP-9/TIMP-1 ratio differed significantly from the baseline level (p<0.01). These changes were not observed in the control group (n=31). In the whole data, salivary MMP-9 and gingival index correlated (r=0.260, p<0.05 at baseline and r=0.354, p<0.01 at the end of the study). Intergroup differences or correlations with other clinical parameters were not found. Probiotic consumption did not affect the saliva flow rate. CONCLUSIONS: Increased MMP-9 and decreased TIMP-1 levels in saliva may indicate that probiotics have immunomodulatory effects in the oral cavity. Furthermore, increased salivary MMP-9 levels may be an indication of the defensive potential of matrix metalloproteinases.

Persistent Oral Human Papillomavirus (HPV) Infection is Associated with Low Salivary Levels of Matrix Metalloproteinase 8 (MMP-8).

BACKGROUND: A persistent human papillomavirus (HPV) infection is a prerequisite for a HPV related cancer to develop. Asymptomatic, persistent HPV infections are not only found in genital tract, but also on oral mucosa. Oral HPV persistence may be associated with behavioural factors, but data on the role of innate immunity in oral HPV infections are still limited. OBJECTIVES: Salivary concentrations of matrix metalloproteinases MMP-8 and MMP-9, tissue inhibitor of MMPs (TIMP-1), myeloperoxidase, and serum concentrations of MMP-8 were analysed in women with a persistent oral HPV infection and, as a control, in women who remained HPV DNA-negative during a 6-year follow-up. The effects of smoking, lactation and alcohol use on the salivary and serum parameters were assessed, too. STUDY DESIGN: A nested case-control setting was used to select a subgroup of 57 women with a persistent oral HPV infection and 102 controls from the Finnish Family HPV Study. RESULTS: The salivary MMP-8/TIMP-1 molar ratio was lower in HPV DNA-positive women than in controls (p=0.036). The difference was more pronounced in non-smoking women, in this group also the salivary MMP-8 levels differed (p=0.047). There was a correlation between the salivary concentrations of myeloperoxidase and MMP-8 (r=0.567, p<0.001) or MMP-9 (r=0.234, p=003), but no correlation between salivary and serum MMP-8 levels. The MMP-9 concentration and the MMP-9/TIMP-1 molar ratio were significantly lower in smokers than in non-smokers (p=0.020 and p=0.003, respectively). CONCLUSIONS: Persistent oral HPV infection was associated with a low salivary MMP-8 concentration indicating eventually a failure in oral anti-inflammatory defence.

Bifidobacteria inhibit the growth of Porphyromonas gingivalis but not of Streptococcus mutans in an in vitro biofilm model.

There is growing interest in the use of probiotic bifidobacteria for enhancement of the therapy, and in the prevention, of oral microbial diseases. However, the results of clinical studies assessing the effects of bifidobacteria on the oral microbiota are controversial, and the mechanisms of actions of probiotics in the oral cavity remain largely unknown. In addition, very little is known about the role of commensal bifidobacteria in oral health. Our aim was to study the integration of the probiotic Bifidobacterium animalis subsp. lactis Bb12 and of oral Bifidobacterium dentium and Bifidobacterium longum isolates in supragingival and subgingival biofilm models and their effects on other bacteria in biofilms in vitro using two different in vitro biofilms and agar-overlay assays. All bifidobacteria integrated well into the subgingival biofilms composed of Porphyromonas gingivalis, Actinomyces naeslundii, and Fusobacterium nucleatum and decreased significantly only the number of P. gingivalis in the biofilms. The integration of bifidobacteria into the supragingival biofilms containing Streptococcus mutans and A. naeslundii was less efficient, and bifidobacteria did not affect the number of S. mutans in biofilms. Therefore, our results suggest that bifidobacteria may have a positive effect on subgingival biofilm and thereby potential in enhancing gingival health; however, their effect on supragingival biofilm may be limited.

Persistent oral human papillomavirus infection is associated with smoking and elevated salivary immunoglobulin G concentration.

BACKGROUND: Prevalence and risk factors for human papillomavirus (HPV) persistence in oral mucosa are largely unknown. Furthermore, the antiviral effects of saliva in the outcome of oral HPV infections are unexplored. OBJECTIVES: To compare the levels of selected salivary defence proteins in women with a persistent oral HPV infection and in those without any signs of oral HPV. Lifestyle factors including the use of oral contraceptives, oral sex, smoking and alcohol drinking habits were also assessed. STUDY DESIGN: This nested case-control study of the Finnish Family HPV Study included 60 women with a persistent oral HPV infection and 117 women who remained HPV DNA negative throughout a 6-year follow-up. Whole saliva samples and oral scrapings for HPV testing were collected at the same visit. The oral HPV status was related to salivary concentrations of lactoferrin, lysozyme, IgA, IgG, total protein and sodium as well as to the use of oral contraceptives, oral sex, smoking and alcohol drinking habits. RESULTS: Women with a persistent oral HPV infection had higher salivary levels of IgG (p=0.007) and lysozyme (p=0.002, when adjusted to the total protein concentration), than those without an HPV infection. Lactoferrin and IgA concentrations were not related to the HPV-status. Smoking increased the risk of a persistent oral HPV infection (p=0.020), but the oral HPV status was not related to other life-style factors studied. CONCLUSIONS: Smoking is a risk factor for a persistent oral HPV infection. Oral HPV infection may be associated with increased concentrations of salivary IgG and lysozyme.

Effects of Lactobacillus reuteri PTA 5289 and L. paracasei DSMZ16671 on the adhesion and biofilm formation of Streptococcus mutans.

Probiotics have decreased the counts of salivary mutans streptococci (MS) in clinical studies. The aim of this study was to compare the effects of Lactobacillus reuteri PTA 5289 and L. paracasei DSMZ16671 on the adhesion of a reference strain and a clinical isolate of Streptococcus mutans and on the counts of MS in a biofilm. The adhesion of S. mutans Ingbritt and the clinical isolate S. mutans 2366 to a smooth glass surface and saliva-coated hydroxyapatite (SHA) were studied in the presence of and without the lactobacilli. A three-species biofilm formed on saliva-coated hydroxyapatite discs was used in the biofilm experiments. The lactobacilli did not affect adhesion to the glass surface but interfered with binding to SHA. No effects of the lactobacilli were detected on the MS levels in the three-species biofilms. The results of the SHA binding experiments best reflected the results of the existing clinical studies.

Adhesion of Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum on bioactive TiO(2) surfaces.

BACKGROUND: Bioactive TiO(2) coatings have been found to enhance fibroblast adhesion and gingival attachment on the titanium surfaces, but no information is available whether the coatings also promote the adhesion of periodontal pathogens. AIM: The purpose of this study was to investigate protein adsorption and the adhesion of Aggregatibacter actinomycetemcomitans (Aa) and Fusobacterium nucleatum (Fn) on bioactive TiO2 surfaces. MATERIALS AND METHODS: Commercially pure titanium discs (diameter 11.0 mm, grade 2) were coated with sol-gel derived bioactive TiO2 coatings (MetAlive, Vivoxid, Turku, Finland) and preincubated in 1.5 ml PBS/diluted serum/diluted saliva at room temperature to mimic the clinical situation after implantation and to allow serum/saliva proteins to adhere on the substrates. Uncoated titanium discs were used as controls. RESULTS: SDS-PAGE revealed similar protein profiles on bioactive and control titanium substrates. No differences were noticed in Aa or Fn adhesion between bioactive and control titanium. However, serum and saliva conditioning diminished Aa adhesion on both surfaces (p<0.001). CONCLUSION: It can be concluded that bioactive TiO2 coating does not promote adhesion of Aa and Fn.

Probiotic Lactobacillus reuteri strains ATCC PTA 5289 and ATCC 55730 differ in their cariogenic properties in vitro.

OBJECTIVE: The effects of probiotics on cariogenic biofilms remain controversial. Our aim was to characterise two probiotic Lactobacillus reuteri strains, ATCC PTA 5289 and ATCC 55730 from a cariogenic standpoint in vitro. These strains are used in commercial products designed for oral health purposes. DESIGN: The adhesion and biofilm formation were studied on saliva-coated hydroxyapatite. The effects of glucose or sucrose on the biofilm formation were also tested. Arginine metabolism was assessed by measuring the pH in the presence of glucose and arginine. The degradation of hydroxyapatite was measured in three different growth media. Streptococcus mutans strains Ingbritt and MT 8148 were used as positive controls for bacterial adhesion and degradation of hydroxyapatite. RESULTS: Strain ATCC PTA 5289 adhered on saliva-coated hydroxyapatite and formed detectable biofilm, but strain ATCC 55730 was poor in both adhesion and biofilm formation. Both strains were arginolytic and raised the pH in the presence of arginine. The amount of dissolved calcium from hydroxyapatite correlated with bacterial growth rate and the final pH of the growth medium. CONCLUSION: L. reuteri strains ATCC PTA 5289 and ATCC 55730 differed in their adhesion, biofilm formation and arginine metabolism in vitro. Thus, these probiotic lactobacilli are likely to differ in their behaviour and cariogenic potential also in an oral environment.

Short-term consumption of probiotic lactobacilli has no effect on acid production of supragingival plaque.

Acidogenicity and the levels of mutans streptococci (MS) in dental plaque after the use of Lactobacillus rhamnosus GG (LGG) and Lactobacillus reuteri were determined. The study had a randomised, double-blind, crossover design. Thirteen volunteers used tablets containing LGG or a combination of L. reuteri SD2112 and PTA 5289 for 2 weeks. At baseline and at the end of each tablet period, all available supragingival plaque was collected. Lactic acid production was determined from a fixed volume (8 µl) of fresh plaque and the rest of the plaque was used for culturing MS and lactobacilli. The retention of probiotics to the plaque was assessed using PCR techniques. No probiotic-induced changes were found in the acidogenicity of plaque. Also, MS counts remained at the original level. The number of subjects with lactobacilli in plaque increased in the L. reuteri group (p = 0.011) but not in the LGG group. PCR analysis of plaque revealed the presence of LGG in four and L. reuteri in six subjects after the use of the probiotic. The use of the lactobacilli did not affect the acidogenicity or MS levels of plaque. Short-term consumption of LGG and L. reuteri appeared not to influence the acidogenicity of plaque.

Probiotic lactobacilli interfere with Streptococcus mutans biofilm formation in vitro.

In clinical studies, probiotic bacteria have decreased the counts of salivary mutans streptococci (MS). We compared the effects of probiotic Lactobacillus strains on the biofilm formation of Streptococcus mutans. The bacterial strains used included four S. mutans strains (reference strains NCTC 10449 and Ingbritt and clinical isolates 2366 and 195) and probiotic strains Lactobacillus rhamnosus GG, L. plantarum 299v, and L. reuteri strains PTA 5289 and SD2112. The ability of MS to adhere and grow on a glass surface, reflecting biofilm formation, was studied in the presence of the lactobacilli (LB). The effect of LB culture supernatants on the viability of the MS was studied as well. All of the LB inhibited the biofilm formation of the clinical isolates of MS (P < 0.001). The biofilm formation of the reference strains of MS was also inhibited by the LB, but L. plantarum and L. reuteri PTA 5289 showed a weaker inhibition when compared to L. reuteri SD2112 and L. rhamnosus GG. Viable S. mutans cells could be detected in the biofilms and culture media only when the experiments were performed with the L. reuteri strains. The L. reuteri strains were less efficient in killing the MS also in the tests performed with the culture supernatants. The pHs of the supernatants of L. reuteri were higher compared to those of L. rhamnosus GG and L. plantarum; P < 0.001. In conclusion, our results demonstrated that four commonly used probiotics interfered with S. mutans biofilm formation in vitro, and that the antimicrobial activity against S. mutans was pH-dependent.

Probiotics and oral health.

The number of products containing probiotics, viable bacteria with proven health benefits, entering the market is increasing. Traditionally, probiotics have been associated with gut health, and most clinical interest has been focused on their use for prevention or treatment of gastrointestinal infections and diseases; however, during the last decade several investigators have also suggested the use of probiotics for oral health purposes. The aim of this review is to examine potential mechanisms of probiotic bacteria in the oral cavity and summarize observed effects of probiotics with respect to oral health. The review focuses on probiotic lactobacilli and bifidobacteria, genera that are most used in various probiotic products.

Sensitivity of Helicobacter pylori to an innate defence mechanism, the lactoperoxidase system, in buffer and in human whole saliva.

Helicobacter pylori has frequently been isolated from human dental plaque, and oral spread via saliva is thought to be one of its principal modes of transmission. Among other innate defence systems human saliva contains peroxidase enzymes and lysozyme. The sensitivity of H. pylori to physiological concentrations of lactoperoxidase and its salivary substrate thiocyanate, and different amounts of hydrogen peroxide (H(2)O(2)) was investigated in buffer and in human whole saliva. The effect of lysozyme was also studied in saliva. All tested H. pylori strains, ATCC 43504(T) and five clinical isolates, were efficiently inhibited by the peroxidase system with high concentrations of H(2)O(2) in buffer. The inhibition was stronger at lower pH. However, in human saliva these high concentrations of H(2)O(2) generated less hypothiocyanite, the antibacterial product of the peroxidase system and the effects of the peroxidase system were weaker. Physiological concentration of lysozyme was not bacteriocidal against H. pylori, nor did it enhance the effect of the peroxidase system in saliva. Thus, further studies are needed to enhance the efficacy of peroxidase systems in human saliva to make it more beneficial not only against dental but also against gastric pathogens.