Treponema denticola Induces Epithelial Barrier Dysfunction in Polarized Epithelial Cells.

Treponema denticola, an anaerobic spirochete found mainly in the oral cavity, is associated with periodontal disease and has a variety of virulence factors. Although in vitro studies have shown that T. denticola is able to penetrate epithelial cell monolayers, its effect on the epithelial barrier junction is not known. Human gingival epithelial cells are closely associated with adjacent membranes, forming barriers in the presence of tight junction proteins, including zonula occludens-1 (ZO-1), claudin-1, and occludin. Tight junction proteins are also expressed by Madin-Darby canine kidney (MDCK) cells in culture. In this study, the MDCK cell profile was investigated following infection with T. denticola (ATCC 35405) wild-type, as well as with its dentilisin-deficient mutant, K1. Basolateral exposure of MDCK cell monolayers to T. denticola at a multiplicity of infection (MOI) of 104 resulted in a decrease in transepithelial electrical resistance (TER). Transepithelial electrical resistance in MDCK cell monolayers also decreased following apical exposure to T. denticola (MOI=104), although this took longer with basolateral exposure. The effect on the TER was time-dependent and required the presence of live bacteria. Meanwhile, MDCK cell viability showed a decrease with either basolateral or apical exposure. Immunofluorescence analysis demonstrated decreases in the amounts of immunoreactive ZO-1 and claudin-1 in association with disruption of cell-cell junctions in MDCK cells exposed apically or basolaterally to T. denticola. Western blot analysis demonstrated degradation of ZO-1 and claudin-1 in culture lysates derived from T. denticola-exposed MDCK cells, suggesting a bacteria-induced protease capable of cleaving these tight junction proteins.

Antimicrobial Susceptibility of Microorganisms Isolated from Periapical Periodontitis Lesions.

Periapical periodontitis usually results from microbial infection, with these microorganisms occasionally migrating to the root canal, which can lead to further, potentially life-threatening, complications. Here, the susceptibility of 27 bacterial strains to various antimicrobial agents was evaluated. These strains comprised 13 species; 16 of the strains were clinical isolates from periapical lesions. Each strain was inoculated onto blood agar plates containing one of the antimicrobial agents. The plates were incubated anaerobically at 37°C for 96 hr and the minimal inhibitory concentrations (MICs) determined. Ten strains required an MIC of 32 µg/ml or greater for amoxicillin, 6 for cefmetazole, and 5 for cefcapene among ß-lactam antibiotics; 8 strains required an MIC of 32 µg/ml or greater for clindamycin, 4 for azithromycin, and 11 for clarithromycin among macrolide antibiotics; 3 strains required an MIC of 32 µg/ml or greater for ciprofloxacin and 2 for ofloxacin among fluoroquinolones. The effect of cefcapene on 5 strains was evaluated after biofilm formation to investigate the relationship between biofilm formation and susceptibility. All strains showed a decrease in susceptibility after biofilm formation. The results revealed that several antimicrobial agents commonly used in a clinical setting, including amoxicillin, cefmetazole, and clindamycin, are potentially effective in the treatment of orofacial odontogenic infections. The development of resistant strains, however, means that this can no longer be guaranteed. In addition, azithromycin, ciprofloxacin, and ofloxacin were more effective than the 3 ß-lactam antibiotics tested. These results suggest that sensitivity testing is needed if odontogenic infections are to be treated safely and effectively.

Effect of clinical factors on bacterial contamination of bone chips collected during implant surgery.

PURPOSE: The objective of this study was to investigate the relationship between various clinical factors and bacterial contamination of bone chips (BC) collected during dental implant surgery and to elucidate how bacterial contamination might be minimized. MATERIALS AND METHODS: Implants were installed in 55 partially edentulous patients (36 men and 19 women), among whom the relationship between various clinical factors and bacterial contamination of BC collected by bone trap was investigated in 37. The effect of rinsing with a saline on BC was determined in 18 patients. Number of contaminating microorganisms was expressed as colony-forming units (CFUs). RESULTS: CFUs in the maxilla were lower than those in the mandible (P < 0.01). CFUs at the incisors or canines were lower than those at the premolars or molars (P < 0.01). Logistic regression analysis revealed a relationship between average bacterial count and duration of surgery (odds ratio, 1.046; 95% CI, 1.012-1.081). Rinsing of BC reduced bacterial contamination. CONCLUSION: Duration of surgery is a major clinical factor affecting contamination risk in BC, and rinsing of BC with a sterile saline solution reduces bacterial number.

Expression of Porphyromonas gingivalis gingipain antigen Hgp44 domain on surface of Lactococcus lactis.

Porphyromonas gingivalis, a pathogen involved in the development of chronic periodontitis, has a number of major virulence factors, among which are its surface cysteine protease gingipains. The purpose of this study was to investigate the feasibility of inducing protective antibodies against P. gingivalis by means of immunization with recombinant Lactococcus lactis expressing the 44-kDa gingipain adhesion/hemagglutinin domain (Hgp44). Part of the Hgp44 sequence encoding the first 314 amino acid residues, residues 188-251, and residues 354-393 was amplified and inserted into shuttle plasmid pSGANC332, with the resulting chimeric plasmids designated as pISTY210, pCOL, and pSHGRP44A, respectively. After confirming the clone sequences, expression of recombinant proteins was investigated by immunoblot. The results revealed that while pISTY210 and pCOL both expressed the Hgp44 antigen on the surface of L. lactis, the level of expression was quite low. To enhance expression of the protein on the surface of the cells, cysteine residues were changed to serine residues by site-directed mutagenesis. Replacement of 3 out of 5 cysteine residues (pISTY213) significantly increased expression of the recombinant protein on the surface of the bacteria. Interestingly, replacement of the 4th cysteine residue (pISTY215) reduced antigenicity of the recombinant protein. These results indicate that expression of Hgp44 on the surface of L. lactis cells requires the replacement of several key cysteine residues, and that L. lactis expressing this antigen could be a promising candidate for immunization against P. gingivalis-induced periodontitis.

Synergistic effect on biofilm formation between Fusobacterium nucleatum and Capnocytophaga ochracea.

The formation of dental plaque biofilm by specific Gram-negative rods and spirochetes plays an important role in the development of periodontal disease. The aim of this study was to characterize biofilm formation by Fusobacterium nucleatum and Capnocytophaga ochracea. Coaggregation between F. nucleatum and Capnocytophaga species was determined by visual assay. Biofilm formation was assessed by crystal violet staining. Enhancement of biofilm formation by F. nucleatum via soluble factor of C. ochracea was evaluated by addition of culture supernatant and a two-compartment separated co-culture system. Production of autoinducer-2 by the tested organisms was evaluated using Vibrio harveyi BB170. F. nucleatum strains coaggregated with C. ochracea ATCC 33596 or ONO-26 strains. Ethylenediamine tetraacetic acid, N-acetyl-d-galactosamine or lysine inhibited coaggregation. Heating or proteinase K treatment of F. nucleatum cells affected coaggregation, whereas the same treatment of C. ochracea cells did not. Co-culture of F. nucleatum with C. ochracea in the same well resulted in a statistically significant increase in biofilm formation. Enhancement of F. nucleatum biofilm formation by a soluble component of C. ochracea was observed using the two-compartment co-culture system (P < 0.05) and confirmed by addition of culture supernatant of C. ochracea (P < 0.01). The present findings indicate that induction of coaggregation and intracellular interaction by release of a diffusible molecule by C. ochracea play a significant role in the formation of biofilm by F. nucleatum and C. ochracea.

Synergy in biofilm formation between Fusobacterium nucleatum and Prevotella species.

The formation of biofilm by anaerobic, Gram-negative bacteria in the subgingival crevice plays an important role in the development of chronic periodontitis. The aim of this study was to characterize the role of coaggregation between Fusobacterium nucleatum and Prevotella species in biofilm formation. Coaggregation between F. nucleatum and Prevotella species was determined by visual assay. Effect of co-culture of the species on biofilm formation was assessed by crystal violet staining. Effect of soluble factor on biofilm formation was also examined using culture supernatant and two-compartment co-culture separated by a porous membrane. Production of autoinducer-2 (AI-2) by the organisms was evaluated using Vibrio harveyi BB170. Cells of all F. nucleatum strains coaggregated with Prevotella intermedia or Prevotella nigrescens with a score of 1-4. Addition of ethylenediamine tetraacetic acid or l-lysine inhibited coaggregation. Coaggregation disappeared after heating of P. intermedia or P. nigrescens cells, or Proteinase K treatment of P. nigrescens cells. Co-culture of F. nucleatum ATCC 25586 with P. intermedia or P. nigrescens strains increased biofilm formation compared with single culture (p < 0.01); co-culture with culture supernatant of these strains, however, did not enhance biofilm formation by F. nucleatum. Production of AI-2 in Prevotella species was not related to enhancement of biofilm formation by F. nucleatum. These findings indicate that physical contact by coaggregation of F. nucleatum strains with P. intermedia or P. nigrescens plays a key role in the formation of biofilm by these strains.

Transmission of periodontopathic bacteria from natural teeth to implants.

PURPOSE: Prevention of peri-implantitis is essential for the success of implant rehabilitation. Infection by periodontopathic bacteria is a major cause of peri-implantitis. The aim of the present study was to identify the source of peri-implant colonization by periodontopathic bacteria. MATERIALS AND METHODS: Twenty-one patients with implants were enrolled in the study. Subgingival plaque samples from the adjacent, occluding, and contralateral natural teeth were collected prior to second-stage surgery. Samples from implant sulci were then obtained 2 weeks later. Detection of periodontopathic bacteria was performed by the polymerase chain reaction. RESULTS: The detection rates for Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, and Fusobacterium nucleatum in all subgingival samples from natural teeth were similar to that in the peri-implant sulci. Multiple logistic regression analysis revealed an association between the detection of A. actinomycetemcomitans, Prevotella intermedia, Porphyromonas gingivalis, Treponema denticola, and F. nucleatum in the gingival crevices of adjacent teeth and that of the peri-implant sulcus, but no association for Tannerella forsythia. CONCLUSIONS: The present findings suggest that colonization by A. actinomycetemcomitans, Prevotella intermedia, Porphyromonas gingivalis, Treponema denticola, and F. nucleatum at the implant sulcus was affected by these microorganisms in the gingival crevice of adjacent teeth rather than those on occluding and contralateral teeth.

HGP44 induces protection against Porphyromonas gingivalis-Induced alveolar bone loss in mice.

The protective effect of DNA vaccines expressing the Arg-gingipain A domain against bone loss induced by Porphyromonas gingivalis infection was investigated in a murine model. phgp44, which expresses the 44-kDa adhesion/hemagglutinin domain of Arg-gingipain A, prevented P. gingivalis-induced alveolar bone loss. The results indicate that phgp44 could be a candidate antigen for a vaccine against P. gingivalis infection.

Effect of smoking on subgingival microflora of patients with periodontitis in Japan.

BACKGROUND: Smoking is a risk factor for periodontitis. To clarify the contribution of smoking to periodontitis, it is essential to assess the relationship between smoking and the subgingival microflora. The aim of this study was to gain an insight into the influence of smoking on the microflora of Japanese patients with periodontitis. METHODS: Sixty-seven Japanese patients with chronic periodontitis (19 to 83 years old, 23 women and 44 men) were enrolled in the present study. They consisted of 30 smokers and 37 non-smokers. Periodontal parameters including probing pocket depth (PPD) and bleeding on probing (BOP) and oral hygiene status were recorded. Detection of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Fusobacterium nucleatum/periodonticum, Treponema denticola and Campylobacter rectus in subgingival plaque samples was performed by polymerase chain reaction. Association between the detection of periodontopathic bacteria and smoking status was analyzed by multiple logistic regression analysis and chi-square test. RESULTS: A statistically significant association was found between having a PPD ≥ 4 mm and detection of T. denticola, P. intermedia, T. forsythia, or C. rectus, with odds ratios ranging from 2.17 to 3.54. A significant association was noted between BOP and the detection of C. rectus or P. intermedia, and smoking, with odds ratios ranging from 1.99 to 5.62. Prevalence of C. rectus was higher in smokers than non-smokers, whereas that of A. actinomycetemcomitans was lower in smokers. CONCLUSIONS: Within limits, the analysis of the subgingival microbial flora in smokers and non-smokers with chronic periodontitis suggests a relevant association between smoking and colonization by the specific periodontal pathogens including C. rectus.

Exposure of P. gingivalis to noradrenaline reduces bacterial growth and elevates ArgX protease activity.

OBJECTIVE: Periodontitis, an infectious disease caused by periodontopathic bacteria, including Porphyromonas gingivalis, is reported to be accelerated by stress, under which noradrenaline levels are increased in the bloodstream. The purpose of this study was to evaluate the effects of noradrenaline on P. gingivalis. DESIGN: P. gingivalis was incubated in the presence of 25µM, 50µM, or 100µM adrenaline or noradrenaline at 37°C for 12, 24 or 36h and growth was evaluated by OD(660). Auto-inducer-2 (AI-2) was measured by luminescence of Vibrio harveyi BB 170. Expression of P. gingivalis genes was evaluated using a microarray and RT-PCR. Rgp activity of arg-gingipainA and B (Rgp) was measured with a synthetic substrate. RESULTS: Growth of P. gingivalis FDC381 was inhibited by noradrenaline at 24 and 36h. Growth inhibition by noradrenaline increased dose-dependently. Inhibition of growth partially recovered with addition of propranolol. AI-2 production from P. gingivalis showed a marked decrease with addition of noradrenaline compared with peak production levels in the control group. Microarray analysis revealed an increase in expression in 18 genes and a decrease in expression in 2 genes. Amongst these genes, expression of the protease arg-gingipainB (RgpB) gene, a major virulence factor of P. gingivalis, was further analysed. Expression of rgpB showed a significant increase with addition of noradrenaline, which was partially reduced by addition of propranolol. Cell-associated Rgp activity also increased with addition of noradrenaline. CONCLUSIONS: These results suggest that stressors influence the expression of the virulence factors of P. gingivalis via noradrenaline.

Hemagglutinin/Adhesin domains of Porphyromonas gingivalis play key roles in coaggregation with Treponema denticola.

Porphyromonas gingivalis and Treponema denticola are major pathogens of periodontal disease. Coaggregation between microorganisms plays a key role in the colonization of the gingival crevice and the organization of periodontopathic biofilms. We investigated the involvement of surface ligands of P. gingivalis in coaggregation. Two triple mutants of P. gingivalis lacking Arg-gingipain A (RgpA), Lys-gingipain (Kgp) and Hemagglutinin A (HagA) or RgpA, Arg-gingipain B (RgpB) and Kgp showed significantly decreased coaggregation with T. denticola, whereas coaggregation with a major fimbriae (FimA)-deficient mutant was the same as that with the P. gingivalis wild-type parent strain. rgpA, kgp and hagA code for proteins that contain 44 kDa Hgp44 adhesin domains. The coaggregation activity of an rgpA kgp mutant was significantly higher than that of the rgpA kgp hagA mutant. Furthermore, anti-Hgp44 immunoglobulin G reduced coaggregation between P. gingivalis wild type and T. denticola. Treponema denticola sonicates adhered to recombinant Rgp domains. Coaggregation following co-culture of the rgpA kgp hagA mutant expressing the RgpB protease with the rgpA rgpB kgp mutant expressing the unprocessed HagA protein was enhanced compared with that of each triple mutant with T. denticola. These results indicate that the processed P. gingivalis surface Hgp44 domains are key adhesion factors for coaggregation with T. denticola.

Fimbriae-associated genes are biofilm-forming factors in Aggregatibacter actinomycetemcomitans strains.

Aggregatibactor actinomycetemcomitans colonizes human periodontal lesions and is implicated in both aggressive periodontitis and chronic periodontitis. Clinical isolated colonies of A. actinomycetemcomitans were rough type. The rough type has a remarkable ability to adhere tenaciously to solid surfaces and colonize firmly. Rough type colonies change into smooth type colonies during the course of repeated inoculation and biofilm-forming activity ceases. Adherence by A. actinomycetemcomitans is mediated by the tight-adherence (tad) gene locus, which includes flp, rcpA and rcpB. In this study, we investigated the relationship between its biofilm-forming ability and expression of the flp, rcpA and rcpB genes associated with fimbriae protein production. First, we changed rough type strain organized biofilm on glass into smooth type and confirmed it by observation of biofilm on glass surfaces. Then, we carried out Real-Time PCR and found that expression of the rcpA and rcpB genes was clearly reduced in smooth type colonies. This suggests that expression of rcpA and rcpB plays a key role in biofilm formation by A. actinomycetemcomitans strains and the establishment of persistent infections in periodontal lesions.

Antimicrobial activity of super-oxidised water against oral microorganisms.

OBJECTIVE: The radical anion of oxygen (O(-)) is extremely oxidative and shows high reactivity. In this study, the antibacterial activity of water super-oxidised water containing high concentration of O(-) (O(-)-water) was tested against cultured planktonic cells of cariogenic bacteria, periodontopathic bacteria and Candida albicans. METHODS: O(-)-water was prepared using the AOE-750 (Oxy Japan Corporation, Japan) and its antibacterial activity against pure culture of Streptococcus sobrinus, Porphyromonas gingivalis, Prevotella intermedia, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum and C. albicans evaluated. Each oral microorganism (10(4) to 10(8)CFU/ml) was exposed to three concentrations of O(-)-water at room temperature or 37 degrees C for 15s to 24h. RESULTS: Exposure to O(-)-water resulted in a bactericidal effect against all cariogenic and periodontopathic bacteria tested. No significant fungicidal effect was observed on C. albicans, however. CONCLUSION: The results demonstrate that O(-)-water exerts an antibacterial effect on cariogenic and periodontopathic bacteria.

Congo red-binding protein in rough-phenotype Aggregatibacter actinomycetemcomitans is amyloid-like fiber.

Aggregatibacter actinomycetemcomitans is a pathogen associated with chronic and aggressive periodontitis and extra-oral infections. Fresh isolates of A. actinomycetemcomitans are fimbriated, forming small, rough-phenotype colonies on agar plates and also form biofilms. Recently, it has been reported that amyloid fibers are abundant in natural biofilms, and Escherichia coli and Salmonella spp. produce amyloid fibers that contribute to biofilm formation. This has yet to be reported, however, in A. actinomycetemcomitans. Amyloid binds the Congo red (CR) dye. In this study, therefore, we investigated amyloid formation in A. actinomycetemcomitans using a detection of CR-binding colonies on CR agar plates and CR-binding assay. All rough-phenotype strains formed dark red colonies and smooth-phenotype strains formed white or opaque red colonies on CR agar plates. Compared with smooth-phenotype strains, rough-phenotype strains showed higher CR-binding activity. CR-binding of rough-phenotype strain AKR was not affected by protease digestion or heating, whereas smooth-phenotype strain 29523 showed a marked reduction in CR-binding after both types of treatment. AKR showed amyloid-positive staining with CR to produce yellow green birefringence under polarized light, whereas 29523 showed amyloid-negative staining. These findings indicate that the CR-binding component of rough-phenotype A. actinomycetemcomitans is an amyloid-like fiber.

Fusobacterium nucleatum enhances invasion of human gingival epithelial and aortic endothelial cells by Porphyromonas gingivalis.

Invasion by Porphyromonas gingivalis has been proposed as a possible mechanism of pathogenesis in periodontal and cardiovascular diseases. Porphyromonas gingivalis have direct access to the systemic circulation and endothelium in periodontitis patients by transient bacteremia. Periodontitis can be described as one of the predominant polymicrobial infections of humans. In the present study, P. gingivalis strains were tested for their ability to invade a human gingival epithelial cell line (Ca9-22) and human aortic endothelial cells in coinfection with Fusobacterium nucleatum using antibiotic protection assays. Coinfection with F. nucleatum resulted in 2-20-fold increase in the invasion of host cells by P. gingivalis strains. The invasive abilities of P. gingivalis strains were significantly greater when incubated with a F. nucleatum clinical isolate (which possesses strong biofilm-forming ability), than when incubated with a F. nucleatum-type strain. In inhibition assays with metabolic inhibitors, a difference in inhibition profiles was observed between mono- and polymicrobial infections. Collectively, our results suggest that F. nucleatum facilitates invasion of host cells by P. gingivalis. Investigations of polymicrobial infection of host cells should improve our understanding of the role of P. gingivalis in periodontal infection and proatherogenic mechanisms.

Relationship between antimicrobial protein levels in whole saliva and periodontitis.

BACKGROUND: Antimicrobial proteins are abundant in saliva. The purpose of this study was to determine and compare the amounts of two types of antibacterial protein, cystatin and lysozyme, in saliva between healthy persons and subjects with periodontitis. METHODS: Forty subjects with periodontitis visiting Tokyo Dental College Chiba Hospital, Chiba, Japan, and 27 healthy persons were evaluated. Whole saliva was collected by requiring all subjects to expectorate into a sterile tube. Salivary levels of cystatin SA, cystatin C, and lysozyme were determined by enzyme-linked immunosorbent assay or immunoblot assay. RESULTS: Cystatin SA levels in saliva from the periodontally diseased group showed a mean value of 0.063 +/- 0.026 mg/ml, statistically lower than that in the healthy group (P <0.05). The average cystatin C level in the periodontally diseased group was 2.27 +/- 1.20 ng/ml, markedly lower than that in the healthy group (3.79 +/- 1.28 ng/ml; P <0.05). Average lysozyme levels in the periodontitis and healthy groups were 16.75 +/- 15.31 microg/ml and 30.03 +/- 15.03 microg/ml, respectively. The lysozyme level in the periodontitis group was significantly lower than in the healthy group (P <0.05). CONCLUSION: Specific monoclonal antibodies are useful for the detection of family 2 cystatins in saliva samples, and the amount of antibacterial protein in saliva offers a potential indicator of the risk for periodontitis.

Nicotine involved in periodontal disease through influence on cytokine levels.

Periodontal disease, for which smoking is a known risk factor, is infectious, and is associated with oral biofilm. Cytokines mediate and regulate immune and inflammatory responses. Lipopolysaccharide produced by periodontopathic bacteria plays a role in the progression of periodontitis. The effect of nicotine on cytokine production in mice was evaluated in this study. Nicotine (10 or 200 microg mouse(-1)) was administered intraperitoneally to 4-week-old female BALB/c mice, once a day, for 49 days. Control mice received injections of phosphate-buffered saline. Blood was collected from all mice and serum IL-6, IL-10, tumor necrosis factor (TNF)-alpha and IFN-gamma levels were measured by an enzyme-linked immunosorbent assay on the 42nd day. IL-6, IL-10 and IFN-gamma levels in the nicotine-treated mice were higher than those in the control mice. However, no differences were found in TNF-alpha levels between nicotine-treated and control mice. Lipopolysaccharide (20 microg mouse(-1)) purified from Aggregatibacter actinomycetemcomitans (formerly Actinobacillus actinomycetemcomitans) Y4 was administered intraperitoneally on the 49th day. A rapid increase in TNF-alpha was observed in the control mice at 2 h after administration of lipopolysaccharide. In contrast, no increase was noted in the nicotine-treated groups. Significantly higher levels of IFN-gamma were seen in the 200 microg nicotine-treated mice at 2 h after administration of lipopolysaccharide (P<0.05). The results showed that cytokine levels were influenced by nicotine in mice.

Tongue-coating as risk indicator for aspiration pneumonia in edentate elderly.

Silent aspiration of oral microorganisms is a major cause of aspiration pneumonia. To establish oral hygiene criteria for the prevention of aspiration pneumonia in edentulous elderly persons, we investigated the relationship between presence of tongue-coating and number of oral bacteria in saliva and episodes of pneumonia. A total of 71 edentulous Japanese people aged 65 years or older living in nursing homes were enrolled in the study. A tongue plaque index (TPI) was used to evaluate quantity of tongue-coating, with TPI0 signifying no tongue-coating and TPI1 signifying presence of tongue-coating. Edentate elderly with TPI1 demonstrated significantly higher salivary bacterial counts than those with TPI0 (p<0.05). The number of elderly patients developing aspiration pneumonia was larger (p<0.005) in patients with TPI-based poor scores (average TPI>0.5) than in those with TPI-based good scores. The relative risk of developing pneumonia in the good tongue hygiene group compared with in the poor tongue hygiene group was 0.12, 95% confidence interval (CI): 0.02-0.9. The results demonstrate that tongue-coating is associated with number of viable salivary bacterial cells and development of aspiration pneumonia, suggesting that tongue-coating is a risk indicator of aspiration pneumonia in edentate subjects.

Inhibitory effect of cranberry polyphenol on cariogenic bacteria.

The purpose of this study was to investigate the effect of cranberry polyphenol fraction on mutans streptococci. Hydrophobicity is an important factor in the adherence of bacteria to the tooth surface. We found that cranberry polyphenol fraction significantly decreased the hydrophobicity of Streptococcus sobrinus 6715, Streptococcus mutans MT8148R and JC2 in a dose-dependent manner (p<0.05). Biofilm formation by S. sobrinus 6715 and S. mutans MT8148R was inhibited by 100 microg/ml cranberry polyphenol fraction (p<0.01). When dosage was increased to 500 microg/ml, biofilm formation by S. mutans JC2 was significantly inhibited (p<0.05). Addition of 500 microg/ml cranberry polyphenol fraction to medium inhibited growth of S. mutans MT8148R compared with the control (p<0.05).

Treponema denticola induces interleukin-8 and macrophage chemoattractant protein 1 production in human umbilical vein epithelial cells.

Treponema denticola, a major pathogen of periodontitis, has also been detected in the lesions of atherosclerosis. The aim of this study was to investigate induction of chemokine production in human umbilical vein endothelial cells (HUVECs) by T. denticola and determine whether those chemokines were degraded by a protease, dentilisin. T. denticola ATCC35405 or dentilisin-deficient mutant K1 were added to HUVECs and levels of interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) in the culture supernatants were determined by enzyme-linked immunosorbent assay. T. denticola ATCC35405 induced production of IL-8 in a time-dependent manner, with both production of IL-8 and expression of IL-8 mRNA showing higher levels than with exposure to dentilisin-deficient mutant K1. Although exposure to ATCC35405 induced expression of MCP-1 mRNA in the HUVECs, MCP-1 levels were remained similar to that in unstimulated cells. IL-8 and MCP-1 showed partial hydrolysis with exposure to T. denticola ATCC35405, but not with T. denticola K1. These results suggest that T. denticola can evade host defense mechanisms by modulating production of IL-8 and MCP-1, and that this play a role in the development of chronic infections such as periodontitis. The association of T. denticola infection to atherosclerosis was also discussed based on the present study.