Probiotics alter biofilm formation and the transcription of Porphyromonas gingivalis virulence-associated genes

Microbiome-based therapies for periodontitis and peri-implantitis

OBJECTIVES

Periodontitis and peri-implantitis are oral infectious-inflammatory diseases associated with oral microbial dysbiosis. Microbiome-based therapies, characterized by manipulation of the microbiota, are emerging as promising therapeutic approaches to resolve the microbial dysbiosis and associated dysregulation of immune system. This review aims at summarizing recent progress on microbiome-based therapies in periodontitis and peri-implantitis, promoting a further understanding of the related therapeutic mechanisms.

SUBJECTS AND METHODS

Pertinent literatures focused on microbiome-based therapies for periodontitis and peri-implantitis are obtained from PubMed and Web of Science.

RESULTS

In this article, we review the roles and therapeutic mechanisms of four microbiome-based therapies, including probiotics, postbiotics, predatory bacteria and phages, and microbiota transplantation, in the management of periodontitis and peri-implantitis. Challenges facing this field are also discussed, highlighting the areas that require more attention and investigation.

CONCLUSIONS

Microbiome-based therapies may serve as effective treatment for periodontitis and peri-implantitis. This review presents a new viewpoint to this field.

Oral Administration of Lactobacillus acidophilus LA5 Prevents Alveolar Bone Loss and Alters Oral and Gut Microbiomes in a Murine Periodontitis Experimental Model

Periodontitis is a destructive inflammatory response triggered by dysbiosis. Lactobacillus acidophilus LA5 (LA5) may impair microbial colonization and alter the host. Thus, we evaluated the effect of LA5 on alveolar bone loss in a periodontitis murine model and investigated its effect on the oral and gut microbiomes. Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Streptococcus gordonii were inoculated in C57BL/6 mice (P+), with LA5 (L+). SHAM infected controls (P- and/or L- groups) were also evaluated. After 45 days, alveolar bone loss in the maxilla and oral and gut microbiomes were determined. The administration of LA5 controlled the microbial consortium-induced alveolar bone loss. Periodontopathogens infection resulted in shifts in the oral and gut microbiomes consistent with dysbiosis, and LA5 reshaped these changes. The oral microbiome of P+L- group showed the increased abundance of Enterococaccea, Streptoccocaceae, Staphylococcaceae, Moraxellaceae, and Pseudomonadaceae, which were attenuated by the administration of LA5 to the infected group (P+L+). The administration of LA5 to otherwise non-infected mice resulted in the increased abundance of the superphylum Patescibacteria and the family Saccharamonadaceae in the gut. These data indicate L. acidophilus LA5 as a candidate probiotic for the control of periodontitis.

Chemical Characterization and Effect of a Lactobacilli-Postbiotic on Streptococcus mutans Biofilm In Vitro

Postbiotic is the term used to define the soluble factors, metabolic products, or byproducts released by live probiotic bacteria or after its lysis. The objective of this study was to carry out the chemical characterization of the postbiotic of Lacticaseibacillus rhamnosus LR-32 and to evaluate its in vitro effect on the development of the Streptococcus mutans biofilm. After the cultivation of the probiotic strain, the postbiotic was extracted by centrifuging the culture and filtering the supernatant. This postbiotic was characterized by using gas chromatography coupled with mass spectrometry (GC-MS), and then it was used to determine the growth inhibition of S. mutans in its planktonic form; additionally, its effects on the following parameters in 48 h biofilm were evaluated: viable bacteria, dry weight, and gene expression of glucosyltransferases and VicR gene. The control group consisted of the biofilm without any treatment. A paired t-test was performed for statistical analysis, with the p-value set at 5%. Seventeen compounds of various chemical classes were identified in the postbiotic, including sugars, amino acids, vitamins, and acids. The treatment with the postbiotic led to an inhibition of the growth of S. mutans in its planktonic form, as well as a decrease in the number of viable bacteria, reduction in dry weight, and a negative regulation of the gene expression of gtfB, gtfC, gtfD, and vicR in its biofilm state, compared with the nontreated group (p < 0.05). The postbiotic of L. rhamnosus impaired the development of S. mutans biofilm.

Manipulating the diseased oral microbiome: the power of probiotics and prebiotics

Dental caries and periodontal disease are amongst the most prevalent global disorders. Their aetiology is rooted in microbial activity within the oral cavity, through the generation of detrimental metabolites and the instigation of potentially adverse host immune responses. Due to the increasing threat of antimicrobial resistance, alternative approaches to readdress the balance are necessary. Advances in sequencing technologies have established relationships between disease and oral dysbiosis, and commercial enterprises seek to identify probiotic and prebiotic formulations to tackle preventable oral disorders through colonisation with, or promotion of, beneficial microbes. It is the metabolic characteristics and immunomodulatory capabilities of resident species which underlie health status. Research emphasis on the metabolic environment of the oral cavity has elucidated relationships between commensal and pathogenic organisms, for example, the sequential metabolism of fermentable carbohydrates deemed central to acid production in cariogenicity. Therefore, a focus on the preservation of an ecological homeostasis in the oral environment may be the most appropriate approach to health conservation. In this review we discuss an ecological approach to the maintenance of a healthy oral environment and debate the potential use of probiotic and prebiotic supplementation, specifically targeted at sustaining oral niches to preserve the delicately balanced microbiome.

Growth Conditions Influence Lactobacillus Cell-Free Supernatant Impact on Viability, Biofilm Formation, and Co-Aggregation of the Oral Periodontopathogens Fusobacterium nucleatum and Porphyromonas gingivalis

Fusobacterium nucleatum and Porphyromonas gingivalis human periodontopathogens play a leading part in oral squamous cell carcinoma through cell proliferation, invasion, and persistent inflammation promotion and maintenance. To explore how the activity of Lactobacillus-derived cell-free supernatants (CFSs) can be influenced by growth medium components, CFSs were produced both in the standard MRS and the novel animal-derivative-free “Terreno Industriale Lattobacilli” (TIL) media, and in vitro screened for the containment of F. nucleatum and P. gingivalis both single and co-cultured and also for the interference on their co-aggregation. The viability assay demonstrated that the Limosilactobacillus reuteri LRE11 and Ligilactobacillus salivarius LS03 MRS-produced CFSs were significantly more effective against single and co-cultured pathogens. All the other CFSs significantly improved their efficacy when produced in TIL. Both MRS- and TIL-produced CFSs significantly inhibited the single and co-cultured pathogen biofilm formation. Only Levilactobacillus brevis LBR01 CFS in MRS specifically reduced F. nucleatum and P. gingivalis co-aggregation, while viable LBR01, LS03, and LRE11 in MRS significantly co-aggregated with the pathogens, but only LS03 cultivated in TIL improved this effect. This work paves the way to better consider environmental growth conditions when screening for probiotic and postbiotic efficacy as crucial to pathogen aggregation, adhesion to the host’s niches, and exclusion.

Lactobacillus reuteri for chronic periodontitis: focus on underlying mechanisms and future perspectives

Chronic periodontitis is a common oral disorder caused by pathogenic bacteria. Despite the wide use of antibiotics as the conventional adjunctive treatment, the challenges of increased antibiotic resistance and limited therapeutic effect receive considerable attention and the developments of alternative treatments gain increasing consideration. Growing evidence showed that Lactobacillus reuteri (LR) may represent a promising alternative adjunct for chronic periodontitis. It can attenuate inflammation and reduce tissue disruption. LR-assisted treatment has been shown to be effective and relatively safe in multiple clinical trials, and accumulating evidence suggests its significant biological roles. In the current review, we focus on capturing the underlying mechanisms of LR involved in chronic periodontitis, thereby representing a scientific foundation for LR-assisted therapy. Furthermore, we point out the challenges and future directions for further clinical trials to improve the clinical applicability for LR.

Probiotic consumption can modify the resilience of periodontal tissues in rats under experimental periodontitis

BACKGROUND

This study evaluated the effects of systemic administration of Bifidobacterium animalis subsp. lactis HN019 (B. lactis HN019) on experimental periodontitis (EP) in rats.

METHODS

Thirty-two rats were allocated to groups C (control), C-HN019 (probiotic), EP (EP only), and EP-HN019 (EP+probiotic). From day 0, the animals of C-HN019 and EP-HN019 groups received B. lactis HN019 (1 × 10⁹ CFU/ml) daily. On the 14th day, the animals of EP and EP-HN019 groups received silk ligature around mandibular molars. Animals were euthanized on the 28th day. Samples of oral biofilm, gingival tissues, blood serum, and mandible were obtained for microtomographic, histomorphometric, microbiological, and immunological analyses. Data were statistically analyzed (p < 0.05).

RESULTS

Group EP-HN019 presented significantly less alveolar bone loss when compared with Group EP in histomorphometric and microtomographic analyses. In gingival tissue and serum, Group EP-HN019 presented lower proinflammatory/anti-inflammatory cytokines ratios than Group EP. Group EP-HN019 showed higher expression of beta-defensins and less TRAP-positive cells than Group EP. Group EP presented higher gene expression of Ifng and lower gene expression of Foxp3 when compared with Group EP-HN019 in gingival tissue. In oral biofilm, EP-HN019 group presented a lower percentage of species similar to Fusobacterium periodonticum and a higher percentage of species similar to Actinomyces gereneseriae, Actinomyces israelli, and Streptococcus gordonii when compared with Group EP. There was a significant increase of B. lactis HN019 after administration of probiotic therapy in oral biofilm of Group EP-HN019.

CONCLUSION

The consumption of B. lactis HN019 promotes a protective effect against alveolar bone loss by modifying local and systemic microbiological and immunoinflammatory parameters.

Lactobacillus acidophilus novel strain, MJCD175, as a potential probiotic for oral health in dogs

The oral cavity is the second-largest habitat for microorganisms, and a well-balanced oral microbiome contributes to preventing dental disorders caused by pathogenic bacteria. Since humans and dogs have different lifestyles and oral microbiome structures, the present study aimed to develop novel probiotics for dogs. A total 53 Lactobacillus spp. were isolated from healthy dogs, and nine isolates were identified as Lactobacillus acidophilus according to 16S rRNA gene sequencing. According to the high antimicrobial activity against the dental caries-causing bacterium Streptococcus mutans, single or three mixed strains were orally administered to dogs for 4 weeks with concentration of 10⁸-10⁹ CFU/day. Intraoral swab samples were collected before and after the administration, and changes of oral pathogen were analyzed using quantitative PCR. Among them, Porphyromonas gingivalis, a critical factor of periodontitis, was significantly reduced in the single-strain administered group. Based on the acid and bile salts tolerance characteristics of isolates, systemic effects were also analyzed by comparing serum immunoglobulin and reproductive ability before and after the administration. However, no significant changes were observed in the serum IgG level and sperm quality. Overall, these in vitro and in vivo results suggest that L. acidophilus isolates from dogs, especially L. acidophilus MJCD175, could be promising probiotic candidates to support oral health without systemic adverse effects in dogs.

Characterization and potential oral probiotic properties of Lactobacillus plantarum FT 12 and Lactobacillus brevis FT 6 isolated from Malaysian fermented food

OBJECTIVE

This study aims to characterise the lactic acid bacteria (LAB) isolated from local Malaysian fermented foods with oral probiotics properties.

DESIGN

The LAB strains isolated from Malaysian fermented foods, Lactobacillus brevis FT 6 and Lactobacillus plantarum FT 12, were assessed for their antimicrobial properties against Porphyromonas gingivalis ATCC 33277 via disc diffusion assay. Anti-biofilm properties were determined by treating the overnight P. gingivalis ATCC 33277 biofilm with different concentrations of LAB cell-free supernatant (LAB CFS). Quantification of biofilm was carried out by measuring the optical density of stained biofilm. The ability of L. brevis FT 6 and L. plantarum FT 12 to tolerate salivary amylase was also investigated. Acid production with different sugars was carried out by pH measurement and screening for potential antimicrobial organic acid by disc diffusion assay of neutralised probiotics CFS samples. In this study, L. rhamnosus ATCC 7469, a commercial strain was used to compare the efficacy of the isolated strain with the commercial strain.

RESULTS

Lactobacillus brevis FT 6 and L. plantarum FT 12 possess antimicrobial activity against P. gingivalis with inhibition diameters of more than 10 mm, and the results were comparable with L. rhamnosus ATCC 7469. The MIC and MBC assay results for all tested strains were recorded to be 25 µl/µl concentration. All LAB CFS reduced biofilm formation proportionally to the CFS concentration and tolerated salivary amylase with more than 50% viability. Overnight cultures of all lactic acid bacteria strains showed a pH reduction and neutralised CFS of all lactic acid bacteria strains did not show any inhibition towards P. gingivalis.

CONCLUSIONS

These results indicate that the isolated probiotics have the potential as probiotics to be used as a supportive oral health treatment, especially against a periodontal pathogen, P. gingivalis.

Increase in Bifidobacterium is a characteristic of the difference in the salivary microbiota of pregnant and non-pregnant women

Background

The establishment of symbiotic microbiota in pregnant women is important for both the mother and her offspring. Little is known about the salivary symbiotic bacteria in pregnancy, and analysis of composition of microbiome (ANCOM) is useful to detect small differences in the number of bacteria. The aim of this study was to investigate the differences in the salivary bacteria between healthy pregnant and non-pregnant women using ANCOM.

Methods

Unstimulated saliva samples were collected from 35 healthy pregnant women at 35 weeks gestation and 30 healthy non-pregnant women during menstruation. All participants underwent a periodontal examination. Estradiol and progesterone levels were examined by enzyme-linked immunosorbent assay. DNA extracted from the saliva was assessed by 16S ribosomal RNA amplicon sequencing and real-time PCR.

Results

Salivary estradiol and progesterone levels were significantly increased in pregnant women. The alpha and beta diversities were higher in pregnant women than in non-pregnant women. The largest effect size difference noted when the microbiota of the pregnant and non-pregnant women were analyzed was that for Bifidobacteriales. Levels of Bifidobacterium dentium, but not of Bifidobacterium adolescentis, were significantly increased in pregnant women, and the levels were significantly correlated with progesterone concentration.

Conclusion

The results suggest that Bifidobacterium and progesterone levels are elevated in the saliva of healthy pregnant women compared with non-pregnant women.

Lactobacilli Attenuate the Effect of Aggregatibacter actinomycetemcomitans Infection in Gingival Epithelial Cells

Probiotics may be considered as an additional strategy to achieve a balanced microbiome in periodontitis. However, the mechanisms underlying the use of probiotics in the prevention or control of periodontitis are still not fully elucidated. This in vitro study aimed to evaluate the effect of two commercially available strains of lactobacilli on gingival epithelial cells (GECs) challenged by Aggregatibacter actinomycetemcomitans. OBA-9 GECs were infected with A. actinomycetemcomitans strain JP2 at an MOI of 1:100 and/or co-infected with Lactobacillus acidophilus La5 (La5) or Lacticaseibacillus rhamnosus Lr32 (Lr32) at an MOI of 1:10 for 2 and 24 h. The number of adherent/internalized bacteria to GECs was determined by qPCR. Production of inflammatory mediators (CXCL-8, IL-1β, GM-CSF, and IL-10) by GECs was determined by ELISA, and the expression of genes encoding cell receptors and involved in apoptosis was determined by RT-qPCR. Apoptosis was also analyzed by Annexin V staining. There was a slight loss in OBA-9 cell viability after infection with A. actinomycetemcomitans or the tested probiotics after 2 h, which was magnified after 24-h co-infection. Adherence of A. actinomycetemcomitans to GECs was 1.8 × 10⁷ (± 1.2 × 10⁶) cells/well in the mono-infection but reduced to 1.2 × 10⁷ (± 1.5 × 10⁶) in the co-infection with Lr32 and to 6 × 10⁶ (± 1 × 10⁶) in the co-infection with La5 (p < 0.05). GECs mono-infected with A. actinomycetemcomitans produced CXCL-8, GM-CSF, and IL-1β, and the co-infection with both probiotic strains altered this profile. While the co-infection of A. actinomycetemcomitans with La5 resulted in reduced levels of all mediators, the co-infection with Lr32 promoted reduced levels of CXCL-8 and GM-CSF but increased the production of IL-1β. The probiotics upregulated the expression of TLR2 and downregulated TLR4 in cells co-infected with A. actinomycetemcomitans. A. actinomycetemcomitans-induced the upregulation of NRLP3 was attenuated by La5 but increased by Lr32. Furthermore, the transcription of the anti-apoptotic gene BCL-2 was upregulated, whereas the pro-apoptotic BAX was downregulated in cells co-infected with A. actinomycetemcomitans and the probiotics. Infection with A. actinomycetemcomitans induced apoptosis in GECs, whereas the co-infection with lactobacilli attenuated the apoptotic phenotype. Both tested lactobacilli may interfere in A. actinomycetemcomitans colonization of the oral cavity by reducing its ability to interact with gingival epithelial cells and modulating cells response. However, L. acidophilus La5 properties suggest that this strain has a higher potential to control A. actinomycetemcomitans-associated periodontitis than L. rhamnosus Lr32.

Outside the limits of bacterial viability: postbiotics in the management of periodontitis

Periodontitis is a major cause of tooth loss in adults worldwide and is caused by an unbalanced oral microbiota in a susceptible host, ultimately leading to tissue breakdown and bone loss. Traditionally, the treatment for periodontitis is scaling and root planing; however, some cases require adjuvant therapy, such as antibiotics administration or surgery. Various factors are involved in the pathogenesis and interact in an unpredictable way, increasing the complexity of the disease and making it difficult to manage. In this context, the administration of probiotics aimed at resolving bacterial dysbiosis and the associated dysregulation of the immune system has been employed in clinical trials with encouraging results. However, the use of viable microorganisms is not risk-free, and immunocompromised patients may develop adverse effects. Therefore, the use of inactivated microbial cells, cell fractions, or soluble products and metabolites of probiotics, known as postbiotics, has gained increasing attention. In this commentary, we present the current literature assessing the impact of postbiotics on the growth and metabolism of periodontal pathogens, as well as on the progression of periodontitis in rodents and humans. We also discuss the limitations of the available data and what the scientific community should consider in order to transfer this innovative therapeutic modality from the bench to the bedside.

Anti-biofilm activities of coumarin as quorum sensing inhibitor for Porphyromonas gingivalis

Porphyromonas gingivalis is a keystone pathogen in periodontitis, a biofilm-mediated infection disease. This research aimed to investigate the effect of coumarin on P. gingivalis biofilm formation. We detected the antimicrobial effect on P. gingivalis planktonic growth, observed membrane structure and morphological change by TEM, and quantified membrane permeability by calcein-AM staining. The cell surface hydrophobicity, aggregation, and attachment were assessed. We also investigated different sub-MIC concentrations of coumarin on biofilm formation, and observed biofilm structureby confocal laser scanning microscopy. The biofilm-related gene expression was evaluated using real-time PCR. The results showed that coumarin inhibited P. gingivalis growth and damaged the cell morphology above 400 μM concentration. Coumarin did not affect cell surface hydrophobicity, aggregation, attachment, and the early stage of biofilm formation at sub-MIC concentrations. Still, it exhibited anti-biofilm effects for the late-stage and pre-formed biofilms dispersion. The biofilms after coumarin treatment became interspersed, and biofilm-related gene expression was downregulated. Coumarin also inhibited AI-2 activity and interacted with the HmuY protein by molecular docking analysis. Our research demonstrated that coumarin inhibited P. gingivalis biofilm formation through a quorum sensing system.

The rationale and potential for using Lactobacillus in the management of periodontitis

Periodontitis refers to a wide range of the inflammatory conditions of supporting dental structures. For some patients with periodontitis, antibacterial agents are needed as an adjuvant to mechanical debridement treatments and oral hygiene maintenance. However, the widespread use of broad-spectrum antibiotics for the prophylaxis and treatment of periodontal infections results in the emergence of resistant pathogens. Therefore, probiotics have become markedly interesting to researchers as a potentially safe alternative to periodontal treatment and maintenance. Probiotics have been used in medicine for decades and extensively applied to the treatment of inflammatory diseases through the modulation of microbial synergy and other mechanisms. A growing amount of evidence has shown that using Lactobacillus strains for oral cavity maintenance could improve periodontal health. In this study, we reviewed studies showing proof of the inhibitory effects of Lactobacillus species on periodontal inflammation. We also explored the rationale and potential for using Lactobacillus species in the management of periodontitis.

Probiotic Species in the Management of Periodontal Diseases: An Overview

Periodontal diseases are one of the most common chronic inflammatory diseases of the oral cavity, which are initiated and sustained by pathogenic plaque biofilms. Central to modern periodontology is the idea that dysbiosis of periodontal microecology and disorder of host inflammatory response gives rise to degradation of periodontal tissues together, which eventually leads to tooth loss, seriously affecting the life quality of patients. Probiotics were originally used to treat intestinal diseases, while in recent years, extensive studies have been exploring the utilization of probiotics in oral disease treatment and oral healthcare. Probiotic bacteria derived from the genera Lactobacillus, Bifidobacterium, Streptococcus, and Weissella are found to play an effective role in the prevention and treatment of periodontal diseases via regulating periodontal microbiota or host immune responses. Here, we review the research status of periodontal health-promoting probiotic species and their regulatory effects. The current issues on the effectiveness and safety of probiotics in the management of periodontal diseases are also discussed at last. Taken together, the use of probiotics is a promising approach to prevent and treat periodontal diseases. Nevertheless, their practical use for periodontal health needs further research and exploration.

Whey fermented by Enterococcus faecalis M157 exhibits antiinflammatory and antibiofilm activities against oral pathogenic bacteria

The aim of the present study was to investigate the antiinflammatory and antibiofilm effects of whey fermented by Enterococcus faecalis M157 (M157-W) against oral pathogenic bacteria. The M157-W significantly inhibited IL-1β, IL-6, and nitric oxide induced by the lipopolysaccharide of Porphyromonas gingivalis in RAW 264.7 cells. The M157-W also inhibited the production of IL-1β and IL-8 in human periodontal ligament cells. Treatment with M157-W suppressed the phosphorylation of mitogen-activated protein kinases as well as the activation of nuclear factor-κB in RAW 264.7 cells stimulated by P. gingivalis lipopolysaccharide. Furthermore, M157-W dose-dependently inhibited Streptococcus mutans biofilm, whereas unfermented whey did not inhibit the biofilm. Treatment with M157-W significantly suppressed gtfB, gtfC, and gtfD gene expression in S. mutans compared with the control (0 μg/mL), indicating that M157-W inhibits S. mutans biofilm formation by reducing the synthesis of extracellular polymeric substances. Collectively, these results suggest that M157-W has antiinflammatory and antibiofilm activities against oral pathogenic bacteria.

Lactobacilli as Anti-biofilm Strategy in Oral Infectious Diseases: A Mini-Review

The spread of biofilm-related diseases in developed countries has led to increased mortality rates and high health care costs. A biofilm is a community of microorganisms that is irreversibly attached to a surface, behaving very differently from planktonic cells and providing resistance to antimicrobials and immune response. Oral diseases are an excellent example of infection associated with the formation of highly pathogenic biofilms. It is generally accepted that, when the oral homeostasis is broken, the overgrowth of pathogens is facilitated. Among them, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans are the main etiological agents of periodontitis, while Streptococcus mutans is strongly associated with the onset of dental caries. Other microorganisms, such as the fungus Candida albicans, may also be present and contribute to the severity of infections. Since the common antibiotic therapies usually fail to completely eradicate biofilm-related oral diseases, alternative approaches are highly required. In this regard, the topical administration of probiotics has recently gained interest in treating oral diseases. Thus, the present mini-review focuses on the possibility of using Lactobacillus spp. as probiotics to counteract biofilm-mediated oral infections. Many evidence highlight that Lactobacillus living cells can impede the biofilm formation and eradicate mature biofilms of different oral pathogens, by acting through different mechanisms. Even more interestingly, lactobacilli derivatives, namely postbiotics (soluble secreted products) and paraprobiotics (cell structural components) are able to trigger anti-biofilm effects too, suggesting that they can represent a novel and safer alternative to the use of viable cells in the management of biofilm-related oral diseases.

Bifidobacterium Strains Present Distinct Effects on the Control of Alveolar Bone Loss in a Periodontitis Experimental Model

Periodontitis is an inflammatory disease induced by a dysbiotic oral microbiome. Probiotics of the genus Bifidobacterium may restore the symbiotic microbiome and modulate the immune response, leading to periodontitis control. We evaluated the effect of two strains of Bifidobacterium able to inhibit Porphyromonas gingivalis interaction with host cells and biofilm formation, but with distinct immunomodulatory properties, in a mice periodontitis model. Experimental periodontitis (P+) was induced in C57Bl/6 mice by a microbial consortium of human oral organisms. B. bifidum 162^2A [B+ (1622)] and B. breve 110^1A [B+ (1101)] were orally inoculated for 45 days. Alveolar bone loss and inflammatory response in gingival tissues were determined. The microbial consortium induced alveolar bone loss in positive control (P + B-), as demonstrated by microtomography analysis, although P. gingivalis was undetected in oral biofilms at the end of the experimental period. TNF-α and IL-10 serum levels, and Treg and Th17 populations in gingiva of SHAM and P + B- groups did not differ. B. bifidum 162^2A, but not B. breve 110^1A, controlled bone destruction in P+ mice. B. breve 110^1A upregulated transcription of Il-1β, Tnf-α, Tlr2, Tlr4, and Nlrp3 in P-B+(1101), which was attenuated by the microbial consortium [P + B+(1101)]. All treatments downregulated transcription of Il-17, although treatment with B. breve 110^1A did not yield such low levels of transcripts as seen for the other groups. B. breve 110^1A increased Th17 population in gingival tissues [P-B+ (1101) and P + B+ (1101)] compared to SHAM and P + B-. Administration of both bifidobacteria resulted in serum IL-10 decreased levels. Our data indicated that the beneficial effect of Bifidobacterium is not a common trait of this genus, since B. breve 110^1A induced an inflammatory profile in gingival tissues and did not prevent alveolar bone loss. However, the properties of B. bifidum 162^2A suggest its potential to control periodontitis.

New tendencies in non-surgical periodontal therapy

The aim of this review was to update the evidence of new approaches to non-surgical therapy (NSPT) in the treatment of periodontitis. Preclinical and clinical studies addressing the benefits of adjunctive antimicrobial photodynamic therapy, probiotics, prebiotics/synbiotics, statins, pro-resolving mediators, omega-6 and -3, ozone, and epigenetic therapy were scrutinized and discussed. Currently, the outcomes of these nine new approaches, when compared with subgingival debridement alone, did not demonstrate a significant added clinical benefit. However, some of these new alternative interventions may have the potential to improve the outcomes of NSPT alone. Future evidence based on randomized controlled clinical trials would help clinicians and patients in the selection of different adjunctive therapies.

Probiotics improve re-epithelialization of scratches infected by Porphyromonas gingivalis through up-regulating CXCL8-CXCR1/CXCR2 axis

Porphyromonas gingivalis inhibits the release of CXCL8 by gingival epithelial cells and reduces their proliferation. We previously reported that Bifidocaterium sp. and Lactobacillus sp. immunomodulate gingival epithelial cells response to this periodontal pathogen, but their effects on re-epithelialization properties are still unknown. Herein we explored these activities of potential probiotics on gingival epithelial cells and clarified their mechanisms. The immortalized OBA-9 lineage was used to perform in vitro scratches. Twelve clinical isolates and commercially available strains of Bifidobacterium sp. and Lactobacillus sp. were screened. L. casei 324 m and B. pseudolongum 119^1A were selected to perform mechanistic assays with P. gingivalis W83 infection and the following parameters were measured: percentage of re-epithelialization by DAPI immunofluorescence area measurement; cell number by Trypan Blue exclusion assay; CXCL8 regulation by ELISA and RT-qPCR; and expression of CXCL8 cognate receptors-CXCR1 and CXCR2 by Flow Cytometry. Complementary mechanistic assays were performed with CXCL8, in the presence or absence of the CXCR1/CXCR2 inhibitor-reparixin. L. casei 324 m and B. pseudolongum 119^1A enhanced re-epithelialization/cell proliferation as well as inhibited the harmful effects of P. gingivalis W83 on these activities through an increase in the expression and release of CXCL8 and in the number of cells positive for CXCR1/CXCR2. Further, we revealed that the beneficial effects of these potential probiotics were dependent on activation of the CXCL8-CXCR1/CXCR2 axis. The current findings indicate that these potential probiotics strains may improve wound healing in the context of the periodontal tissues by a CXCL8 dependent mechanism.

Treatment challenges and delivery systems in immunomodulation and probiotic therapies for periodontitis

Introduction: Periodontitis is a widespread illness that arises due to disrupted interplay between the oral microbiota and the host immune response. In some cases, conventional therapies can provide temporary remission, although this is often followed by disease relapse. Recent studies of periodontitis pathology have promoted the development of new therapeutics to improve treatment options, together with local application using advanced drug delivery systems.Areas covered: This paper provides a critical review of the status of current treatment approaches to periodontitis, with a focus on promising immunomodulation and probiotic therapies. These are based on delivery of small molecules, peptides, proteins, DNA or RNA, and probiotics. The key findings on novel treatment strategies and formulation of advanced delivery systems, such as nanoparticles and nanofibers, are highlighted.Expert opinion: Multitarget therapy based on antimicrobial, immunomodulatory, and probiotic active ingredients incorporated into advanced delivery systems for application to the periodontal pocket can improve periodontitis treatment outcomes. Translation of such adjuvant therapy from laboratory to patient is expected in the future.

Lactobacilli postbiotics reduce biofilm formation and alter transcription of virulence genes of Aggregatibacter actinomycetemcomitans

Periodontitis is characterized by a dysbiotic microbial community and treatment strategies include the reestablishment of symbiosis by reducing pathogens abundance. Aggregatibacter actinomycetemcomitans (Aa) is frequently associated with rapidly progressing periodontitis. Since the oral ecosystem may be affected by metabolic end-products of bacteria, we evaluated the effect of soluble compounds released by probiotic lactobacilli, known as postbiotics, on Aa biofilm and expression of virulence-associated genes. Cell-free pH-neutralized supernatants (CFS) of Lactobacillus rhamnosus Lr32, L. rhamnosus HN001, Lactobacillus acidophilus LA5, and L. acidophilus NCFM were tested against a fimbriated clinical isolate of Aa JP2 genotype (1 × 10⁷  CFU/well) on biofilm formation for 24 hr, and early and mature preformed biofilms (2 and 24 hr). Lactobacilli CFS partially reduced Aa viable counts and biofilms biomass, but did not affect the number of viable non-adherent bacteria, except for LA5 CFS. Furthermore, LA5 CFS and, in a lesser extent HN001 CFS, influenced Aa preformed biofilms. Lactobacilli postbiotics altered expression profile of Aa in a strain-specific fashion. Transcription of cytolethal distending toxin (cdtB) and leukotoxin (ltxA) was downregulated by CFS of LA5 and LR32 CFS. Although all probiotics produced detectable peroxide, transcription of katA was downregulated by lactobacilli CFS. Transcription of dspB was abrogated by LR32 and NCFM CFS, but increased by HN001, whereas expression of pgA was not affected by any postbiotic. Our data indicated the potential of postbiotics from lactobacilli, especially LA5, to reduce colonization levels of Aa and to modulate the expression of virulence factors implicated in evasion of host defenses.

Antagonist effect of probiotic bifidobacteria on biofilms of pathogens associated with periodontal disease

The in vitro antagonist growth effect of bifidobacteria were evaluated on periodontal bacteria. Bifidobacterium longum, Bifidobacterium lactis and Bifidobacterium infantis biofilms were grown in single, double or triple combinations with putative periodontal pathogens P. gingivalis and F. nucleatum or beneficial bacteria S. oralis for 24, 72 and 168 h and the total counts were analyzed by checkerboard DNA-DNA hybridization. The results showed that B. infantis and B. lactis, as single species, demonstrated the best antagonist effect on F. nucleatum and P. gingivalis and no influence on S. oralis growth at 168 h. All the double combinations of bifidobacteria tested demonstrated an inhibitory effect on F. nucleatum (72 h) and P. gingivalis (168 h) and did not affect S. oralis counts at any time. In conclusion, B. lactis and B. infantis alone or in double combinations have antagonist effect on periodontopathogens biofilms, at different time points, and minimal influence on S. oralis growth.