Protective Potential of Non-Dialyzable Material Fraction of Cranberry Juice on the Virulence ofP. gingivalisandF. nucleatumMixed Infection

A state-of-the-art review of the recent advances in drug delivery systems for different therapeutic agents in periodontitis

Periodontitis (PD) is a chronic gum illness that may be hard to cure for a number of reasons, including the fact that no one knows what causes it, the side effects of anti-microbial treatment, and how various kinds of bacteria interact with one another. As a result, novel therapeutic approaches for PD treatment must be developed. Additionally, supplementary antibacterial regimens, including local and systemic medication administration of chemical agents, are necessary for deep pockets to assist with mechanical debridement of tooth surfaces. As our knowledge of periodontal disease and drug delivery systems (DDSs) grows, new targeted delivery systems like extracellular vesicles, lipid-based nanoparticles (NPs), metallic NPs, and polymer NPs have been developed. These systems aim to improve the targeting and precision of PD treatments while reducing the systemic side effects of antibiotics. Nanozymes, photodermal therapy, antibacterial metallic NPs, and traditional PD therapies have all been reviewed in this research. Medicinal herbs, antibiotics, photothermal therapy, nanozymes, antibacterial metallic NPs, and conventional therapies for PD have all been examined in this research. After that, we reviewed the key features of many innovative DDSs and how they worked for PD therapy. Finally, we have discussed the advantages and disadvantages of these DDSs.

Microbiological and Clinical Effects of a Proanthocyanidin-enriched Extract from Rumex acetosa in Periodontally Healthy Carriers of Porphyromonas gingivalis: a Randomized Controlled Pilot Study

Rumex acetosa significantly inhibits the adhesion of Porphyromonas gingivalis (P. g.) to eukaryotic host cells in vitro. The objective of this randomized placebo-controlled pilot-trial was to analyze effects of a mouth rinse containing 0.8% (w/w) of a quantified proanthocyanidin-enriched extract from Rumex acetosa (RA1) on microbiological, clinical, and cytological parameters in systemically healthy individuals without history of periodontitis, harboring P. g. intraorally. 35 subjects received a supragingival debridement (SD) followed by mouth rinsing (3 times daily) with either RA1 mouth rinse solution (test) or placebo (control) for 7 days as adjunct to routine oral hygiene. Supragingival biofilm samples were taken at screening visit, baseline (BL), 2, 4, 7 and 14 days after SD. P. g. and 11 other oral microorganisms were detected and quantified by rtPCR. Changes in the oral microbiota composition of one test and one control subject were assessed via high throughput 16S rRNS gene amplicon sequencing. Approximal Plaque Index (API) and the modified Sulcular Bleeding Index (SBI) were assessed at BL, 7- and 14-days following SD. Brush biopsies were taken at BL and 14 d following SD. Intergroup comparisons revealed no significant microbiological, cytological, and clinical differences at any timepoint. However, a significant reduction in SBI at day 14 (p = 0.003) and API at day 7 (p = 0.02) and day 14 (p = 0.009) was found in the test group by intragroup comparison. No severe adverse events were observed. The results indicate that RA1 mouth rinse is safe but does not seem to inhibit colonization of P. g. or improve periodontal health following SD.

Antimicrobial activity of Desplac® oral gel in the subgingival multispecies biofilm formation

Natural products are well-known due to their antimicrobial properties. This study aimed to evaluate the antimicrobial effect of Desplac® product (composed of Aloe Vera, Propolis Extract, Green Tea, Cranberry, and Calendula) on the subgingival biofilm. Two different protocols were used to treat the 33-species biofilms: (A) 2×/day (12/12  h) for 1  min with Desplac® or Noplak Toothpaste (Chlorhexidine + Cetylpyridinium Chloride) or Oral B ProGengiva (stannous Fluoride) or a placebo gel; (B) a 12-h use of the Desplac® product or 0.12% chlorhexidine gel or a placebo gel. After 7 days of biofilm formation, the metabolic activity (MA) and biofilm profile were determined by 2,3,5-triphenyltetrazolium chloride and Checker-board DNA-DNA hybridization, respectively. Statistical analysis used the Kruskal-Wallis test followed by Dunn's post-hoc. In protocol A, all treatments presented reduced MA compared to the placebo (p ≤ 0.05). The Desplac®-treated biofilm showed a similar microbial profile to other antimicrobials, although with higher bacterial total counts. In protocol B, MA of Desplac®-treated biofilms was lower than the placebo's MA but higher than chlorhexidine-treated biofilms (p ≤ 0.05). Pathogen levels in Desplac®-treated biofilms were lower than in placebo-treated biofilms and elevated compared to the chlorhexidine-treated biofilms (p ≤ 0.05). Desplac® inhibited the biofilm development and disrupted the mature subgingival biofilm, highlighting its effect on Tannerella forsythia counts.

The effect of cranberry juice and a cranberry functional beverage on the growth and metabolic activity of selected oral bacteria

BACKGROUND

The oral microbiota is a significant risk indicator for oral diseases, such as dental caries and periodontal inflammation. Much attention is presently paid to the development of functional foods (e.g. beverages containing cranberry constituents, or foods containing probiotics) that may serve as adjuncts for oral disease treatments (e.g. periodontitis and caries). Cranberry fruit, due to its unique chemical composition and antimicrobial potential, is a possible ingredient of such foods. The study aimed to investigate the effects of cranberry juice (CJ) and a cranberry functional beverage (mixture of 80% v/v apple juice, 20% v/v cranberry juice, and 0.25 g/100 mL ground cinnamon; CFB) on the growth and metabolic activity of selected oral bacteria.

METHODS

Serial dilution pour plate method (SDPP) was used to examine the effect of CJ and CFB on the growth of Actinomyces naeslundii, Streptococcus mutans, and Lactobacillus paracasei subsp. paracasei. 48-h electrical impedance measurements (EIM) during the cultivation of A. naeslundii were applied to evaluate the utility of the method as a rapid alternative for the assessment of the antimicrobial potential of cranberry beverages.

RESULTS

The tested bacteria differed in their susceptibility to the antimicrobial action of CJ and CFB, with L. paracasei subsp. paracasei being least vulnerable to CFB (according to SDPP). Although CJ at a concentration of 0.5 mL/mL, showed a bactericidal effect on the growth of S. mutans, A. naeslundii was more sensitive to CJ (SDPP). Its inhibitory effect on A. naeslundii was seen even at concentrations as small as 0.03125-0.125 mL/mL (SDPP and EIM). On the other hand, S. mutans seemed to be more vulnerable to CFB than A. naeslundii (SDPP).

CONCLUSIONS

CFB may be considered an adjunct in the treatment of oral diseases due to its action against selected oral pathogens, and not against the presumably beneficial L. paracasei subsp. paracasei. Bioelectrical impedance measurements appear to be a quick alternative to evaluating the antimicrobial activity of fruit beverages, but their utility should be confirmed with tests on other bacteria.

Effect of cranberry juice deacidification on its antibacterial activity against periodontal pathogens and its anti-inflammatory properties in an oral epithelial cell model

Cranberries are widely recognized as a functional food that can promote oral health. However, the high concentration of organic acids in cranberry juice can cause tooth enamel erosion. Electrodialysis with bipolar membrane (EDBM) is a process used for the deacidification of cranberry juice. The present study investigated whether the removal of organic acids (0%, 19%, 42%, 60%, and 79%) from cranberry juice by EDBM affects its antibacterial activity against major periodontopathogens as well as its anti-inflammatory properties in an oral epithelial cell model. A deacidification rate ≥60% attenuated the bactericidal effect against planktonic and biofilm-embedded Aggregatibacter actinomycetemcomitans but had no impact on Porphyromonas gingivalis and Fusobacterium nucleatum. Cranberry juice increased the adherence of A. actinomycetemcomitans and P. gingivalis to oral epithelial cells, but reduced the adherence of F. nucleatum by half regardless of the deacidification rate. F. nucleatum produced more hydrogen sulfide when it was exposed to deacidified cranberry juice with a deacidification rate ≥42% compared to the raw beverage. Interestingly, the removal of organic acids from cranberry juice lowered the cytotoxicity of the beverage for oral epithelial cells. Deacidification attenuated the anti-inflammatory effect of cranberry juice in an in vitro oral epithelial cell model. The secretion of IL-6 by lipopolysaccharide (LPS)-stimulated oral epithelial cells exposed to cranberry juice increased proportionally with the deacidification rate. No such effect was observed with respect to the production of IL-8. This study provided evidence that organic acids, just like phenolic compounds, might contribute to the health benefits of cranberry juice against periodontitis.

Proanthocyanidins and Flavan-3-ols in the Prevention and Treatment of Periodontitis-Immunomodulatory Effects, Animal and Clinical Studies

This paper continues the systematic review on proanthocyanidins and flavan-3-ols in the prevention and treatment of periodontal disease and covers the immunomodulatory effects, and animal- and clinical studies, while the other part discussed the direct antibacterial properties. Inflammation as a major response of the periodontal tissues attacked by pathogenic microbes can significantly exacerbate the condition. However, the bidirectional activity of phytochemicals that simultaneously inhibit bacterial proliferation and proinflammatory signaling can provide a substantial alleviation of both cause and symptoms. The modulatory effects on various aspects of inflammatory and overall immune response are covered, including confirmed and postulated mechanisms of action, structure activity relationships and molecular targets. Further, the clinical relevance of flavan-3-ols and available outcomes from clinical studies is analyzed and discussed. Among the numerous natural sources of flavan-3-ols and proanthocyanidins the most promising are, similarly to antibacterial properties, constituents of various foods, such as fruits of Vaccinium species, tea leaves, grape seeds, and tannin-rich medicinal herbs. Despite a vast amount of in vitro and cell-based evidence of immunomodulatory there are still only a few animal and clinical studies. Most of the reports, regardless of the used model, indicated the efficiency of these phytochemicals from cranberries and other Vaccinium species and tea extracts (green or black). Other sources such as grape seeds and traditional medicinal plants, were seldom. In conclusion, the potential of flavan-3-ols and their derivatives in prevention and alleviation of periodontal disease is remarkable but clinical evidence is urgently needed for issuing credible dietary recommendation and complementary treatments.

Proanthocyanidins and Flavan-3-Ols in the Prevention and Treatment of Periodontitis-Antibacterial Effects

Flavan-3-ols and their oligomeric forms called proanthocyanidins are polyphenolic compounds occurring in several foodstuffs and in many medicinal herbs. Their consumption is associated with numerous health benefits. They exhibit antioxidant, anti-inflammatory, cytoprotective, as well as antimicrobial activity. The latter property is important in the prevention and treatment of periodontal diseases. Periodontitis is a multifactorial polymicrobial infection characterized by a destructive inflammatory process affecting the periodontium. Using non-toxic and efficient natural products such as flavanol derivatives can significantly contribute to alleviating periodontitis symptoms and preventing the disease’s progress. Therefore, a comprehensive systematic review of proanthocyanidins and flavan-3-ols in the prevention and treatment of periodontitis was performed. The present paper reviews the direct antibacterial effects of these compounds against periodontic pathogens. The immunomodulatory effects, including animal and clinical studies, are included in a separate, parallel article. There is significant evidence supporting the importance of the antibacterial action exerted by proanthocyanidins from edible fruits, tea, and medicinal herbs in the inhibition of periodontitis-causing pathogens.

American cranberries and health benefits - an evolving story of 25 years

Cranberries contain various types of bioactive components. Scientists have been studying cranberries' beneficial effects on urinary tract health since the 20th century. In the 21st century, the protection provided by cranberry phytochemicals against cancer and vascular diseases has drawn more attention from researchers. Anthocyanins, procyanidins, and flavonols in cranberries were all documented to have potential effects on cancer prevention. The cardiometabolic effects of cranberries have been investigated in several clinical trials. It was found that cranberries positively affect atherosclerotic cholesterol profiles and that they reduced several cardiometabolic risk factors. Nowadays, growing evidence suggests other important roles of cranberries in maintaining digestive health. Cranberry juice or cranberries have been shown to inhibit the colonization of H. pylori in stomach, and protect against intestinal inflammation. For future research, clinical trials with improved study design are urgently needed to demonstrate cranberries' benefits on urinary tract health and cardiometabolic diseases. Hypothesis-driven studies using animals or cell culture are needed to elucidate the mechanisms of cranberries' effects on digestive health. © 2018 Society of Chemical Industry.

New Evidences of Antibacterial Effects of Cranberry Against Periodontal Pathogens

The worrying rise in antibiotic resistances emphasizes the need to seek new approaches for treating and preventing periodontal diseases. The purpose of this study was to evaluate the antibacterial and anti-biofilm activity of cranberry in a validated in vitro biofilm model. After chemical characterization of a selected phenolic-rich cranberry extract, its values for minimum inhibitory concentration and minimum bactericidal concentration were calculated for the six bacteria forming the biofilm (Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans). Antibacterial activity of the cranberry extract in the formed biofilm was evaluated by assessing the reduction in bacteria viability, using quantitative polymerase chain reaction (qPCR) combined with propidium monoazide (PMA), and by confocal laser scanning microscopy (CLSM), and anti-biofilm activity by studying the inhibition of the incorporation of different bacteria species in biofilms formed in the presence of the cranberry extract, using qPCR and CLSM. In planktonic state, bacteria viability was significantly reduced by cranberry (p < 0.05). When growing in biofilms, a significant effect was observed against initial and early colonizers (S. oralis (p ≤ 0.017), A. naeslundii (p = 0.006) and V. parvula (p = 0.010)) after 30 or 60 s of exposure, while no significant effects were detected against periodontal pathogens (F. nucleatum, P. gingivalis or A. actinomycetemcomitans (p > 0.05)). Conversely, cranberry significantly (p < 0.001 in all cases) interfered with the incorporation of five of the six bacteria species during the development of 6 h-biofilms, including P. gingivalis, A. actinomycetemcomitans, and F. nucleatum. It was concluded that cranberry had a moderate antibacterial effect against periodontal pathogens in biofilms, but relevant anti-biofilm properties, by affecting bacteria adhesion in the first 6 h of development of biofilms.

Nupharidine enhances Aggregatibacter actinomycetemcomitans clearance by priming neutrophils and augmenting their effector functions

OBJECTIVES

Nupharidine (6,6'-Dihydroxythiobinupharidine), purified from the aquatic plant Nuphar lutea leaves (Water lily) prompts antimicrobial activity of immune cells. The aim of the study was to test the effect of Nupharidine on neutrophil function against Aggregatibacter actinomycetemcomitans, JP2 clone (Aa-JP2).

METHODS

Neutrophils derived from the human cell line HL60 and human peripheral blood derived from aggressive periodontitis and periodontally healthy subjects were incubated with Nupharidine or vehicle and inoculated with JP2. Bacterial survival was tested using viable counts on blood agar (CFU's). Neutrophils' necrosis/apoptosis, reactive oxygen species (ROS) production, phagocytosis and neutrophil extracellular traps (NET) production following infection were tested, as well as markers of neutrophil priming.

RESULTS

Nupharidine had no direct bactericidal effect on JP2, but it enhanced Aa-JP2 clearance by neutrophils. Nupharidine enhanced neutrophil phagocytosis, ROS production and NET formation during JP2 infection. Furthermore, Nupharidine enhanced the expression of certain markers of neutrophils priming, specifically iCAM1, DECTIN-2 and intracellular IL-1β.

CONCLUSION

Nupharidine was shown to promote neutrophil effector bactericidal functions, boosting Aa-JP2 clearance. The results point to the potential of Nupharidine as an adjunctive agent in the treatment of Aa-JP2 periodontitis, but this should be tested initially using pre-clinical and clinical studies.

Consumption of cranberry functional beverage reduces gingival index and plaque index in patients with gingivitis

Periodontal disease is highly prevalent worldwide, and consumption of certain foods, such as fruits, seem to improve the effectiveness of periodontal therapy (PT) due to their antiadhesive, immunomodulatory, and antioxidative properties. We hypothesized that the cranberry functional beverage (CFB) consumed for eight weeks improves gingival inflammation indices via inhibition of dental plaque, and alterations in antioxidant status, and systemic inflammation in patients with gingivitis. In this two-arm randomized controlled study, fifty participants were divided into an experimental group (CFB), administered daily with 750 ml CFB, or a control group administered the same amount of water. All patients underwent nonsurgical PT prior to the intervention. Gingival (GI) and bleeding on probing (BoP) indices of inflammation, plaque (PI) and approximal plaque (API) indices of dental plaque deposition, saliva and serum total antioxidant status (TAS), serum malonylodialdehyde level (MDA), and interleukin 1-beta level (IL-1beta) were measured pre- and postintervention. A risk of caries development was determined by Streptococcus mutans (SM) and Lactobacillus spp. (LAB) counts in supragingival dental plaque. Changes in GI and PI but not BoP and API were significantly more pronounced in the CFB group compared to the control group. Serum or saliva TAS, IL-1beta, and MDA did not differ between groups. The number of SM reduced in CFB, but not in the control group. We demonstrated that the consumption of CFB improves gingival and plaque indices without posing a risk of caries development. Thus CFB can be recommended as a safe adjunct for nonsurgical PT in patients with gingivitis.

Combined antioxidant effects of Neem extract, bacteria, red blood cells and Lysozyme: possible relation to periodontal disease

Background

The common usage of chewing sticks prepared from Neem tree (Azadirachta indica) in India suggests its potential efficacy in periodontal diseases. The objective of this study is to explore the antibacterial effects of Neem leaf extract on the periodontophatic bacteria Porphyromonas gingivalis and Fusobacterium nucleatum, and its antioxidant capacities alone and in combination with bacteria and polycationic peptides that may be at the site of inflammation.

Methods

Neem leaf extract was prepared by ethanol extraction. The growth kinetics of P. gingivalis and F. nucleatum under anaerobic conditions in the presence of Neem leaf extract were measured. Broth microdilution test was used to determine the Minimal Inhibitory Concentration (MIC) of Neem leaf extract against each bacterial strain. The effect of Neem leaf extract on the coaggregation of the bacteria was assessed by a visual semi-quantitative assay. The antioxidant capacities of Neem leaf extract alone and in combination with bacteria, with the addition of red blood cells or the polycationic peptides chlorhexidine and lisozyme, were determined using a chemiluminescence assay.

Results

Neem leaf extract showed prominent dose-dependent antibacterial activity against P. gingivalis, however, had no effect on the growth of F. nucleatum nor on the coaggregation of the two bacteria. Yet, it showed intense antioxidant activity, which was amplified following adherence to bacteria and with the addition of red blood cells or the polycationic peptides.

Conclusions

Neem leaf extract, containing polyphenols that adhere to oral surfaces, have the potential to provide long-lasting antibacterial as well as synergic antioxidant activities when in complex with bacteria, red blood cells and lisozyme. Thus, it might be especially effective in periodontal diseases.

Phytochemicals for human disease: An update on plant-derived compounds antibacterial activity

In recent years, many studies have shown that phytochemicals exert their antibacterial activity through different mechanisms of action, such as damage to the bacterial membrane and suppression of virulence factors, including inhibition of the activity of enzymes and toxins, and bacterial biofilm formation. In this review, we summarise data from the available literature regarding the antibacterial effects of the main phytochemicals belonging to different chemical classes, alkaloids, sulfur-containing phytochemicals, terpenoids, and polyphenols. Some phytochemicals, besides having direct antimicrobial activity, showed an in vitro synergistic effect when tested in combination with conventional antibiotics, modifying antibiotic resistance. Review of the literature showed that phytochemicals represent a possible source of effective, cheap and safe antimicrobial agents, though much work must still be carried out, especially in in vivo conditions to ensure the selection of effective antimicrobial substances with low side and adverse effects.

Biological Effects of Medicinal Plants on Induced Periodontitis: A Systematic Review

Objective. The aim of this systematic review was to investigate the advances in the study of medicinal plants and their biologic effects on periodontitis in animal models. Study Design. A systematic search was conducted by three independent researchers, who screened articles published up to March/2016, to identify the studies that contained sufficient and clear information on the association of the medicinal plants and periodontitis in murine models. The searches were performed using PubMed, Cochrane, and Science Direct databases. Results. After a critical analysis of titles and abstracts, 30 studies were finally eligible for analysis. The studies presented a great diversity of the experiment designed regarding the methods of induced periodontitis and the evaluation of the medicinal plants efficacy. None of the studies described the possible toxic effects associated with the administration of the plant material to animals and whether they could prevent damage to organs caused by systemic effect of induced periodontitis. Gel-based formulations containing plant substances are seen as an interesting strategy to treat periodontitis. Conclusions. In this systematic review, the state-of-the-art knowledge on the medicinal plants and the induced periodontitis was critically evaluated and discussed from the experiment designed to the possible clinical application.

Inhibitory effect of cranberry extract on periodontopathogenic biofilm: An integrative review

Background:

Combating biofilm-dependent oral infections involves the use of synthetic antibiotics, which are often associated with bacterial resistance and adverse effects. As a result, herbs such as cranberry have emerged as an alternative treatment. The aim of this study was to evaluate, through an integrative literature review, the effectiveness of cranberry extract on cultures and biofilms of periodontopathogenic bacteria.

Materials and Methods:

In vitro and in vivo studies evaluating the action of cranberry extract on the growth, coaggregation and formation of periodontopathogenic bacteria and periodontal biofilm were identified. Searches were carried out in the “Cochrane Library,” “MEDLINE,” “Web of Science,” “Scopus,” “LILACS,” “Scielo,” and “Google Scholar” databases, using the terms: “vaccinium macrocarpon;” “cranberries;” “cranberry;” “biofilms;” “periodontitis;” “chronic periodontitis;” “aggressive periodontitis;” “periodontal diseases;” and “periodont*.”

Results:

a low number of studies evaluating the effectiveness of cranberry extract on periodontal disease were found, and no human studies were identified. In general, the eight studies included in the revision found that the compounds effectively inhibited the formation of a biofilm of Porphyromonas gingivalis and Fusobacterium nucleatum at concentrations equal or superior to 62.5 μg/ml, but did not significantly inhibit bacterial growth or promote the breakdown of preformed biofilm.

Conclusions:

while most of the studies presented certain methodological limitations, they did identify an inhibiting effect of cranberry on periodontal bacteria. These results serve as support for the development of further studies evaluating the most effective vehicle and ideal concentration that can be used without causing adverse effects on oral tissues.

Impact of Cranberries on Gut Microbiota and Cardiometabolic Health: Proceedings of the Cranberry Health Research Conference 2015

Recent advances in cranberry research have expanded the evidence for the role of this Vaccinium berry fruit in modulating gut microbiota function and cardiometabolic risk factors. The A-type structure of cranberry proanthocyanidins seems to be responsible for much of this fruit's efficacy as a natural antimicrobial. Cranberry proanthocyanidins interfere with colonization of the gut by extraintestinal pathogenic Escherichia coli in vitro and attenuate gut barrier dysfunction caused by dietary insults in vivo. Furthermore, new studies indicate synergy between these proanthocyanidins, other cranberry components such as isoprenoids and xyloglucans, and gut microbiota. Together, cranberry constituents and their bioactive catabolites have been found to contribute to mechanisms affecting bacterial adhesion, coaggregation, and biofilm formation that may underlie potential clinical benefits on gastrointestinal and urinary tract infections, as well as on systemic anti-inflammatory actions mediated via the gut microbiome. A limited but growing body of evidence from randomized clinical trials reveals favorable effects of cranberry consumption on measures of cardiometabolic health, including serum lipid profiles, blood pressure, endothelial function, glucoregulation, and a variety of biomarkers of inflammation and oxidative stress. These results warrant further research, particularly studies dedicated to the elucidation of dose-response relations, pharmacokinetic/metabolomics profiles, and relevant biomarkers of action with the use of fully characterized cranberry products. Freeze-dried whole cranberry powder and a matched placebo were recently made available to investigators to facilitate such work, including interlaboratory comparability.

Long-term evaluation of oral gavage with periodontopathogens or ligature induction of experimental periodontal disease in mice

OBJECTIVE

To evaluate in long-term periods the destruction of periodontal tissues and bacterial colonization induced by oral gavage with periodontopathogens or ligature experimental periodontal disease models.

MATERIAL AND METHODS

Forty-eight C57BL/6 J mice were divided into four groups: group C: negative control; group L: ligature; group G-Pg: oral gavage with Porphyromonas gingivalis; and group G-PgFn: oral gavage with Porphyromonas gingivalis associated with Fusobacterium nucleatum. Mice were infected by oral gavage five times in 2-day intervals. After 45 and 60 days, animals were sacrificed and the immune-inflammatory response in the periodontal tissue was assessed by stereometric analysis. The alveolar bone loss was evaluated by live microcomputed tomography and histometric analysis. qPCR was used to confirm the bacterial colonization in all the groups. Data were analyzed using the Kruskal-Wallis, Wilcoxon, and ANOVA tests, at 5 % of significance level.

RESULTS

Ligature model induced inflammation and bone resorption characterized by increased number of inflammatory cells and decreased number of fibroblasts, followed by advanced alveolar bone loss at 45 and 60 days (p < 0.05). Bacterial colonization in groups G-Pg and G-PgFn was confirmed by qPCR but inflammation and bone resorption were not observed (p < 0.05).

CONCLUSIONS

The ligature model but not the oral gavage models were effective to induce inflammation and bone loss in long-term periods. Pg colonization was observed in all models of experimental periodontal disease induction, independent of tissue alterations. These mice models of periodontitis validates, compliments, and enhances published PD models that utilize ligature or oral gavage and supports the importance of a successful colonization of a susceptible host, a bacterial invasion into vulnerable tissue, and host-bacterial interactions that lead to tissue destruction.

CLINICAL RELEVANCE

The ligature model was an effective approach to induce inflammation and bone loss similar to human periodontitis, but the oral gavage models were not efficient in inducing periodontal inflammation and tissue destruction in the conditions studied. Ligature models can provide a basis for future interventional studies that contribute to the understanding of the disease pathogenesis and the complex host response to microbial challenge.

Toll-Like Receptor 9-Mediated Inflammation Triggers Alveolar Bone Loss in Experimental Murine Periodontitis

Chronic periodontitis is a local inflammatory disease induced by a dysbiotic microbiota and leading to destruction of the tooth-supporting structures. Microbial nucleic acids are abundantly present in the periodontium, derived through release after phagocytic uptake of microbes and/or from biofilm-associated extracellular DNA. Binding of microbial DNA to its cognate receptors, such as Toll-like receptor 9 (TLR9), can trigger inflammation. In this study, we utilized TLR9 knockout (TLR9(-/-)) mice and wild-type (WT) controls in a murine model of Porphyromonas gingivalis-induced periodontitis and report the first in vivo evidence that TLR9 signaling mediates the induction of periodontal bone loss. P. gingivalis-infected WT mice exhibited significantly increased bone loss compared to that in sham-infected WT mice or P. gingivalis-infected TLR9(-/-) mice, which were resistant to bone loss. Consistent with this, the expression levels of interleukin 6 (IL-6), tumor necrosis factor (TNF), and receptor-activator of nuclear factor kappa B ligand (RANKL) were significantly elevated in the gingival tissues of the infected WT mice but not in infected TLR9(-/-) mice compared to their levels in controls. Ex vivo studies using splenocytes and bone marrow-derived macrophages revealed significantly diminished cytokine production in TLR9(-/-) cells relative to the cytokine production in WT cells in response to P. gingivalis, thereby implicating TLR9 in inflammatory responses to this organism. Intriguingly, compared to the cytokine production in WT cells, TLR9(-/-) cells exhibited significantly decreased proinflammatory cytokine production upon challenge with lipopolysaccharide (LPS) (TLR4 agonist) or Pam3Cys (TLR2 agonist), suggesting possible cross talk between TLR9, TLR4, and TLR2. Collectively, our results provide the first proof-of-concept evidence implicating TLR9-triggered inflammation in periodontal disease pathogenesis, thereby identifying a new potential therapeutic target to control periodontal inflammation.

Drug resistance of bacterial dental biofilm and the potential use of natural compounds as alternative for prevention and treatment

Oral diseases, such as dental caries and periodontal disease are directly linked with the ability of bacteria to form biofilm. The development of dental caries involves acidogenic and aciduric Gram-positive bacteria colonizing the supragingival biofilm (Streptococcus, Lactobacillus and Actinomycetes). Periodontal diseases have been linked to anaerobic Gram-negative bacteria forming a subgingival plaque (Porphyromonas gingivalis, Actinobacillus, Prevotella and Fusobacterium). Cells embedded in biofilm are up to 1000-fold more resistant to antibiotics compared to their planctonic ones. Several mechanisms have been proposed to explain biofilms drug resistance. Given the increased bacterial resistance to antibiotics currently used in dentistry, a great importance is given to natural compounds for the prevention of oral bacterial growth, adhesion and colonization. Over the past decade, interest in drugs derived from medicinal plants has markedly increased. It has been well documented that medicinal plants and natural compounds confer considerable antibacterial activity against various microorganisms including cariogenic and periodontal pathogens. This paper provides a review of the literature focusing on the studies on (i) biofilm in the oral cavity, (ii) drug resistance of bacterial biofilm and (iii) the potential use of plant extracts, essential oils and natural compounds as biofilm preventive agents in dentistry, involving their origin and their mechanism of biofilm inhibition.

Cranberry proanthocyanidins have anti-biofilm properties against Pseudomonas aeruginosa

BACKGROUND

Bacteria within a biofilm are phenotypically more resistant to antibiotics, desiccation, and the host immune system, making it an important virulence factor for many microbes. Cranberry juice has long been used to prevent infections of the urinary tract, which are often related to biofilm formation. Recent studies have found that the A-type proanthocyanidins from cranberries have anti-biofilm properties against Escherichia coli.

METHODS

Using crystal violet biofilm staining, resazurin metabolism assays, and confocal imaging, we examined the ability of A-type proanthocyanidins (PACs) to disrupt the biofilm formation of Pseudomonas aeruginosa. We used mass spectrometry to analyze the proteomic effects of PAC treatment. We also performed synergy assays and in vitro and in vivo infections to determine whether PACs, alone and in combination with gentamicin, could contribute to the killing of P. aeruginosa and the survival of cell lines and G. mellonella.

RESULTS

Cranberry PACs reduced P. aeruginosa swarming motility. Cranberry PACs significantly disrupted the biofilm formation of P. aeruginosa. Proteomics analysis revealed significantly different proteins expressed following PAC treatment. In addition, we found that PACs potentiated the antibiotic activity of gentamicin in an in vivo model of infection using G. mellonella.

CONCLUSIONS

Results suggest that A-type proanthocyanidins may be a useful therapeutic against the biofilm-mediated infections caused by P. aeruginosa and should be further tested.

Strategies for the inhibition of gingipains for the potential treatment of periodontitis and associated systemic diseases

Gingipains are the major virulence factors of Porphyromonas gingivalis, the main periodontopathogen. It is expected that inhibition of gingipain activity in vivo could prevent or slow down the progression of adult periodontitis. To date, several classes of gingipain inhibitors have been recognized. These include gingipain N-terminal prodomains, synthetic compounds, inhibitors from natural sources, antibiotics, antiseptics, antibodies, and bacteria. Several synthetic compounds are potent gingipain inhibitors but inhibit a broad spectrum of host proteases and have undesirable side effects. Synthetic compounds with high specificity for gingipains have unknown toxicity effects, making natural inhibitors more promising as therapeutic gingipain blockers. Cranberry and rice extracts interfere with gingipain activity and prevent the growth and biofilm formation of periodontopathogens. Although the ideal gingipain inhibitor has yet to be discovered, gingipain inhibition represents a novel approach to treat and prevent periodontitis. Gingipain inhibitors may also help treat systemic disorders that are associated with periodontitis, including cardiovascular disease, rheumatoid arthritis, aspiration pneumonia, pre-term birth, and low birth weight.