An in vitro model demonstrating homeostatic interactions between reconstructed human gingiva and a saliva-derived multispecies biofilm
Bibliographic record
Abstract
BACKGROUND: In the oral cavity, host-microbe interactions (HMI) continuously occur and greatly impact oral health. In contrast to the well-studied disease-associated HMI during, for example, periodontitis, HMI that are essential in maintaining oral health have been rarely investigated, especially in a human-relevant context. The aim of this study was to extensively characterize homeostatic HMI between saliva-derived biofilms and a reconstructed human gingiva (RHG). RHG was reconstructed following the structure of native gingiva, composed of a multilayered epithelium formed by keratinocytes and a fibroblast-populated compartment. To mimic the oral environment, RHG were inoculated with pooled human saliva resuspended in different saliva substitute media and incubated for 2 or 4 days. The co-cultured biofilms were retrieved and characterized by viable bacterial counting and compositional profiling (16S rRNA gene sequencing). RHG was investigated for metabolic activity (MTT assay), tissue histology (hematoxylin and eosin staining), epithelial proliferation (Ki67 staining), antimicrobial peptide expression, and cytokine secretion. RESULTS: Viable biofilms were detected up to day 4 of co-culturing. Bacterial counts indicated biofilm growth from the inoculation to day 2 and maintained thereafter at a similar level until day 4. All biofilms shared similar composition throughout 4 days, independent of co-culture time and different saliva substitute media used during inoculation. Biofilms were diverse with Streptococcus, Haemophilus, and Neisseria being the dominating genera. While supporting biofilm development, RHG displayed no significant changes in metabolic activity, tissue histology, or epithelial proliferation. However, in the presence of biofilms, the antimicrobial peptides elafin and human β-defensin-2 were upregulated, and the secretion of cytokines IL-6, CXCL1, CXCL8, CCL5, and CCL20 increased. CONCLUSION: This model mimicked homeostatic HMI where a healthy gingiva supported a viable, diverse, and stable microbial community, incorporating bacterial genera found on native gingiva. The gingiva model maintained its tissue integrity and exerted protective responses in the presence of biofilms over time. This study adds to the evidence that shows the important role of the host in maintaining homeostatic HMI that are essential for oral health. Video Abstract.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".