Development of an in vitroperiodontal biofilm model for assessing antimicrobial and host modulatory effects of bioactive molecules

Abstract

BackgroundInflammation within the oral cavity occurs due to dysregulation between microbial biofilms and the host response. Understanding how different oral hygiene products influence inflammatory properties is important for the development of new products. Therefore, creation of a robust host-pathogen biofilm platform capable of evaluating novel oral healthcare compounds is an attractive option. We therefore devised a multi-species biofilm co-culture model to evaluate the naturally derived polyphenol resveratrol (RSV) and gold standard chlorhexidine (CHX) with respect to anti-biofilm and anti-inflammatory properties.MethodsAn in vitro multi-species biofilm containing S. mitis, F. nucleatum, P. gingivalis and A. actinomycetemcomitans was created to represent a disease-associated biofilm and the oral epithelial cell in OKF6-TERT2. Cytotoxicity studies were performed using RSV and CHX. Multi-species biofilms were either treated with either molecule, or alternatively epithelial cells were treated with these prior to biofilm co-culture. Biofilm composition was evaluated and inflammatory responses quantified at a transcriptional and protein level.ResultsCHX was toxic to epithelial cells and multi-species biofilms at concentrations ranging from 0.01-0.2%. RSV did not effect multi-species biofilm composition, but was toxic to epithelial cells at concentrations greater than 0.01%. In co-culture, CHX-treated biofilms resulted in down regulation of the inflammatory chemokine IL-8 at both mRNA and protein level. RSV-treated epithelial cells in co-culture were down-regulated in the release of IL-8 protein, but not mRNA.ConclusionsCHX possesses potent bactericidal properties, which may impact downstream inflammatory mediators. RSV does not appear to have bactericidal properties against multi-species biofilms, however it did appear to supress epithelial cells from releasing inflammatory mediators. This study demonstrates the potential to understand the mechanisms by which different oral hygiene products may influence gingival inflammation, thereby validating the use of a biofilm co-culture model.

In Vitro Effect of Porphyromonas gingivalis Methionine Gamma Lyase on Biofilm Composition and Oral Inflammatory Response

“…Broths used were Schaedler’s Anaerobic broth (SCH), BHI and Tryptic Soy broth (+0.8% w/v glucose and 0.6% w/v yeast extract; TSB). In maintaining and building up the 10-species biofilms, the medium Artificial Saliva (AS) was exclusively used [16]. …”

“…Ten-species biofilms were built up on Thermanox coverslips as detailed elsewhere [16, 19] in the following order: an initial 3-species biofilm consisting of S . mitis , S .…”

“…gingivalis for 4h and 24h as described previously [16]. Six stimulations were performed on three occasions using independent batches of biofilms, with the supernatant samples pooled to obtain triplicate samples per batch.…”

Fungi at the Scene of the Crime: Innocent Bystanders or Accomplices in Oral Infections?

“…Polymicrobial communities are able to form biofilms upon this vast variety of substrates [5••, 6, 7]. It is now generally well understood that dental plaque biofilms contain many resident species that modulate one another, their environment, and also the host response [8][9][10]. Despite the widely acknowledged presence of yeasts within the oral cavity, their active role and participation in oral diseases is generally perceived to be restricted to mucosal-related diseases.…”

Insights into the Evolution of Host Association through the Isolation and Characterization of a Novel Human Periodontal Pathobiont,Desulfobulbus oralis

“…Some species are potentially beneficial, contributing to a healthy oral homeostasis, while others are associated with various stages of gingivitis and periodontitis, potentially acting as keystone species and/or virulent components of the disease-inducing microbiota (6). Studies with pure cultures, defined communities in vitro, and animal models have revealed proinflammatory characteristics and interspecies signaling that result in community shifts and a host response leading to tissue destruction (15,16). However, approximately one-third of the oral microbial species-level taxa are still uncultured, including dozens of diseaseassociated lineages (17).…”