Effect of Lactobacillus acidophilus and Porphyromonas gingivalis on proliferation and apoptosis of gingival epithelial cells

Effect of Motiflor AS probiotic for oral health on cell viability in human gingival fibroblasts and human dental pulp stem cells

Objectives

In this study, it was aimed to investigate the possible effects of oral chewable probiotic tablets (PTs) produced to directly support the oral flora on the proliferation of human dental pulp stem cells (DPSCs) and human gingival fibroblast cells (HGFCs).

Materials and Methods

For analysis in this study, "Motiflor AS," a PT that dissolves in the mouth, containing 13.5mg Lactobacillus helveticus Rosell-52, L. rhamnosus Rosell-11, L. halivarus HA-118, and Bifidobacterium longum Rosell-175 was used. Cell survival and proliferation were analyzed by methyl-thiazole-diphenyl-tetrazolium (MTT) test and real-time cell analysis method (xCELLigence RTCA-DP) after 24-, 48-, and 72-h incubation periods.

Results

According to the data obtained with RTCA-DP software, there was a significant increase in the proliferation of human dental pulp stem cells (HDPSCs) and HGFCs in the 72-h incubation after PT application compared to the 24-h and 48-h incubations (P < 0.0001). After the MTT test, for HDPSCs, the cell proliferation rate was 62.8% and 85.6% in 24- and 48-h incubation, respectively, while HDPSCs cell proliferation rate in 72-h incubation was 135.2% (P < 0.0001). For HGFCs, the cell proliferation rate was 73% and 120.4% in 24- and 48-h incubation, respectively, while HDPSCs cell proliferation rate in 72-h incubation was 139.8% (P < 0.0001). When the results of the two tests applied were evaluated together, the results showed compatibility.

Conclusions

Based on the results, it has been concluded that PT will be useful for maintaining oral health and for dental and gingival patients who will/have undergone dental treatment. It should be keep in mind that protecting our oral and dental health is very important in terms of protecting our general health.

Evaluation of Antioxidant and Antibacterial Effects of Lyophilized Cell-Free Probiotic Supernatants of Three Lactobacillus spp. and Their Cytocompatibility Against Periodontal Ligament Stem Cells

Background

Periodontitis is a chronic disease characterized by the inflammation of the periodontium and leads to progressive damage, such as gingival atrophy, alveolar bone loss, and tooth loss. Streptococcus mutans and Aggregatibacter actinomycetemcomitans are bacteria that support the occurrence of periodontitis via the ability to form biofilms or damage the alveolar bone and periodontal ligaments. On the other hand, periodontal ligament stem cells (PDLSCs) are cells with differentiation capability into osteoblasts or osteoblasts. Due to their role in periodontal homeostasis and regeneration, PDLSCs are considered to control periodontitis progression. However, probiotics are helpful microorganisms known to have antimicrobial and immune-regulating effects.

Objectives

This study aimed to evaluate the antioxidant activity and antimicrobial effects of lyophilized cell-free supernatants (LCFSs) derived from three probiotic strains of Lactobacillus on S. mutans and A. actinomycetemcomitans. Moreover, the effect of these lyophilized supernatants was investigated on the viability and migration capability of PDLSCs.

Methods

The antibacterial effects of LCFSs of three probiotic bacteria were investigated by determining the minimum inhibitory concentration and minimum bactericidal concentration. Then, the effect of LCFSs on the survival and migration of PDLSCs was investigated by the MTT method (at 24 and 72 hours) and scratch test (at 0, 24, and 48 hours), respectively. Finally, the antioxidant effect of LCFSs was assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and ferric reducing/antioxidant power methods.

Results

The antibacterial properties of different concentrations of acidic and neutral LCFSs derived from three studied probiotic bacteria on S. mutans and A. actinomycetemcomitans were observed within the range of 12.5 - 50% (v/v) (1/8 - 1/2 dilutions with culture medium). Although there were no significant toxic (~ 100% viability) and wound healing effects on PDLSCs when the cells were exposed to either acidic or neutral studied LCFSs in a concentration of 5% (v/v), they showed significant antioxidant activity (~ 90% DPPH inhibition and 0.5 mM Fe2+/L).

Conclusions

The results revealed that 5% (v/v) 48-hour acidic and neutral supernatants of three studied probiotics might play a beneficial role in controlling 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.

What do we know about the mechanisms of action of probiotics on factors involved in the pathogenesis of periodontitis? A scoping review of in vitro studies

OBJECTIVE

Probiotics are increasingly used in oral prevention and treatment conditions, but little is known about their abilities. The aim of this review is to clarify, summarize and disseminate current knowledge about the mode of action of in vitro probiotics on factors involved in the pathogenesis of periodontitis.

METHOD

2495 articles were identified in three databases (Medline, Web of Science, SpringerLink) and 26 studies included in this scoping review.

RESULTS

Twenty-three probiotic species were identified, the majority of which were Lactobacilli or Bifidobacteria. Lactobacillus rhamnosus (30.8 %) and Lactobacillus reuteri (42.3 %) were found to be the two predominantly studied probiotic species and three main mechanisms of action of probiotics could be classified as: (i) modulation of the immuno-inflammatory response, (ii) direct actions of probiotics on periodontopathogens by adhesion or nutritive competitions and/or the secretion of antimicrobial molecules and (iii) indirect actions through environmental modifications. A combination of several probiotic strains seems to be beneficial via synergistic action amplifying the functions of each strain used. However, heterogeneity of the methodologies and probiotic species included in studies leads us to consider the following avenues for future research: (i) implementation of standardized periodontal models as close as possible to in vivo periodontal conditions to identify the functions of each strain for appropriate medication, (ii) updating data about interactions within oral biofilms to identify new candidates and to predict then analyze their behavior within these biofilms.

CONCLUSION

Probiotics may have their place in the response to inter-individual variability in periodontitis, provided that the choice of the probiotic strain or combination of them will be personalized and optimal for each patient.

Gut microbiota and the periodontal disease: role of hyperhomocysteinemia

Periodontal disease is one of the most common conditions resulting from poor oral hygiene and is characterized by a destructive process in the periodontium that essentially includes gingiva, alveolar mucosa, cementum, periodontal ligament, and alveolar bone. Notably, the destructive event in the alveolar bone has been linked to homocysteine (Hcy) metabolism; however, it has not been fully investigated. Therefore; the implication of Hcy towards initiation, progression, and maintenance of the periodontal disease remains incompletely understood. Higher levels of Hcy (also known as hyperhomocysteinemia (HHcy)) exerts deleterious effects on gum health and teeth in distinct ways. Firstly, increased production of proinflammatory cytokines such as TNF-α, IL-1β, IL-6, and IL-8 leads to an inflammatory cascade of events that affect methionine (Met) and Hcy metabolism (i.e., 1-carbon metabolism) leading to HHcy. Secondly, metabolic dysregulation during chronic medical conditions increases systemic inflammation leading to a decrease in vitamins, more specifically B6, B12, and folic acid, that play important roles as cofactors in Hcy metabolism. Also, given the folate level in the HHcy state that is important during dysbiosis, these two conditions appear to be intimately related, and in this context, HHcy-induced dysbiosis may be one of the potential causes of periodontal disease. This paper sums up the link between periodontitis and HHcy, with a special emphasis on the "oral-gut microbiome axis" and the potential probiotic intervention towards warding off some of the serious periodontal disease conditions.

Oral commensal bacteria differentially modulate epithelial cell death

OBJECTIVE

Epithelial cell death is an important innate mechanism at mucosal surfaces, which enables the elimination of pathogens and modulates immunoinflammatory responses. Based on the antimicrobial and anti-inflammatory properties of cell death, we hypothesized that oral epithelial cell (OECs) death is differentially modulated by oral bacteria.

MATERIAL AND METHODS

We evaluated the effect of oral commensals Streptococcus gordonii (Sg), Streptococcus sanguinis (Ss), and Veillonella parvula (Vp), and pathogens Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf), and Fusobacterium nucleatum (Fn) on OEC death. Apoptosis and necrosis were evaluated by flow cytometry using FITC Annexin-V and Propidium Iodide staining. Caspase-3/7 and caspase-1 activities were determined as markers of apoptosis and pyroptosis, respectively. IL-1β and IL-8 protein levels were determined in supernatants by ELISA.

RESULTS

Significant increases in apoptosis and necrosis were induced by Sg and Ss. Pg also induced apoptosis, although at a substantially lower level than the commensals. Vp, Tf, and Fn showed negligible effects on cell viability. These results were consistent with Sg, Ss, and Pg activating caspase-3/7. Only Ss significantly increased the levels of activated caspase-1, which correlated to IL-1β over-expression.

CONCLUSIONS

OEC death processes were differentially induced by oral commensal and pathogenic bacteria, with Sg and Ss being more pro-apoptotic and pro-pyroptotic than pathogenic bacteria. Oral commensal-induced cell death may be a physiological mechanism to manage the extent of bacterial colonization of the outer layers of mucosal epithelial surfaces. Dysbiosis-related reduction or elimination of pro-apoptotic oral bacterial species could contribute to the risk for persistent inflammation and tissue destruction.

Exploring the role of oral microorganisms in the pathogenesis of mucositis by assessing their impact on metabolic activity and reproductive capacity of epithelial cells in vitro

Purpose

Clinical and in vitro studies showed selected oral microorganisms to be related to delayed wound healing and ulcerative oral mucositis. However, it is not known whether this effect is due to reduced metabolism and/or the reduced reproductive capacity of epithelial cells. Therefore, we studied the influence of the oral microorganisms Porphyromonas gingivalis, Candida glabrata, and Candida kefyr on cell metabolism and reproductive capacity of oral epithelial cells, aimed to further unravel the pathogenesis of oral mucositis.

Methods

Oral epithelial cells were exposed to different concentrations of P. gingivalis, C. glabrata, and C. kefyr as mono-infections or mixed together. An MTT assay was performed to determine the effect on cell metabolism. A clonogenic assay was used to study the effect on the reproductive capacity of oral epithelial cells.

Results

The metabolism of oral epithelial cells was reduced when the microorganisms were present in high concentrations: P. gingivalis at a multiplicity of infection (MOI) of 1000 and the Candida spp. at MOI 100. No statistical difference was observed in the ability of a single epithelial cell to grow into a colony of cells between control and P. gingivalis, C. glabrata, and C. kefyr, independent of the concentrations and combinations used.

Conclusion

P. gingivalis, C. glabrata, and C. kefyr lowered the metabolic activity of oral epithelial cells in high concentrations, yet they did not influence the reproductive capacity of epithelial cells. Their impact on ulcerative oral mucositis is likely due to an effect on the migration, proliferation, and metabolism of epithelial cells.