Microbiological profile and calprotectin expression in naturally occurring and experimentally induced gingivitis

Inflammation and tissue remodeling mediator expression during gingivitis: A comparison between experimental, naturally occurring gingivitis, and periodontal health

BACKGROUND

The aim of this study is to evaluate the immune regulation and tissue remodeling responses during experimental gingivitis (EG) and naturally occurring gingivitis (NG) to provide a comprehensive analysis of host responses. Gingival crevicular fluid (GCF) was obtained from 2 human studies conducted in university settings.

METHODS

The EG study enrolling 26 volunteers provided controls for the baseline (Day 0) from healthy disease-free participants, while Day 21 (the end of EG induction of the same group) was used to represent EG. Twenty-six NG participants age-matched with those of the EG group were recruited. GCF samples were analyzed for 39 mediators of inflammatory/immune responses and tissue remodeling using commercially available bead-based multiplex immunoassays. The differences in GI and mediator expression among groups were determined at a 95% confidence level (p ≤ 0.05) by a 2-way analysis of variance (ANOVA) with a post-hoc Tukey's test.

RESULTS

Our findings showed that EG had a greater gingival index than NG and was healthy (p < 0.01 of all comparisons). Furthermore, EG showed significantly higher levels of MPO (p < 0.001), CCL3 (p < 0.05), and IL-1B (p < 0.001) than NG. In contrast, NG had increased levels of MIF (p < 0.05), Fractalkine (p < 0.001), angiogenin (p < 0.05), C3a (p < 0.001), BMP-2 (p < 0.001), OPN (p < 0.05), RANKL (p < 0.001), and MMP-13 (p < 0.001) than EG.

CONCLUSIONS

Consistent with the findings from chronic (NG) versus acute (EG) inflammatory lesions, these data reveal that NG displays greater immune regulation, angiogenesis, and bone remodeling compared to EG.

Antimicrobial peptides: Defending the mucosal epithelial barrier

The recent epidemic caused by aerosolized SARS-CoV-2 virus illustrates the importance and vulnerability of the mucosal epithelial barrier against infection. Antimicrobial proteins and peptides (AMPs) are key to the epithelial barrier, providing immunity against microbes. In primitive life forms, AMPs protect the integument and the gut against pathogenic microbes. AMPs have also evolved in humans and other mammals to enhance newer, complex innate and adaptive immunity to favor the persistence of commensals over pathogenic microbes. The canonical AMPs are helictical peptides that form lethal pores in microbial membranes. In higher life forms, this type of AMP is exemplified by the defensin family of AMPs. In epithelial tissues, defensins, and calprotectin (complex of S100A8 and S100A9) have evolved to work cooperatively. The mechanisms of action differ. Unlike defensins, calprotectin sequesters essential trace metals from microbes, which inhibits growth. This review focuses on defensins and calprotectin as AMPs that appear to work cooperatively to fortify the epithelial barrier against infection. The antimicrobial spectrum is broad with overlap between the two AMPs. In mice, experimental models highlight the contribution of both AMPs to candidiasis as a fungal infection and periodontitis resulting from bacterial dysbiosis. These AMPs appear to contribute to innate immunity in humans, protecting the commensal microflora and restricting the emergence of pathobionts and pathogens. A striking example in human innate immunity is that elevated serum calprotectin protects against neonatal sepsis. Calprotectin is also remarkable because of functional differences when localized in epithelial and neutrophil cytoplasm or released into the extracellular environment. In the cytoplasm, calprotectin appears to protect against invasive pathogens. Extracellularly, calprotectin can engage pathogen-recognition receptors to activate innate immune and proinflammatory mechanisms. In inflamed epithelial and other tissue spaces, calprotectin, DNA, and histones are released from degranulated neutrophils to form insoluble antimicrobial barriers termed neutrophil extracellular traps. Hence, calprotectin and other AMPs use several strategies to provide microbial control and stimulate innate immunity.

Levels of myeloid-related proteins in saliva for screening and monitoring of periodontal disease

AIM

To evaluate the salivary levels of myeloid-related markers in relation to periodontal disease and their potential screening capability, as well as the effects of periodontal treatment on these markers in periodontitis patients.

MATERIALS AND METHODS

Participants with a healthy periodontium (n = 60) and with gingivitis (n = 63) and periodontitis (n = 72) were recruited. Periodontitis patients received non-surgical treatment and were re-examined after 3 and 6 months. Unstimulated saliva was collected at baseline and at 1, 3, and 6 months after therapy for the periodontitis patients. Levels of colony-stimulating factor-1 (CSF-1), interleukin-34 (IL-34), S100A8/A9, S100A12, hepatocyte growth factor (HGF), IL-1β, and matrix metalloproteinase-8 (MMP-8) were analysed by immunoassays.

RESULTS

CSF-1, S100A8/A9, S100A12, IL-1β, MMP-8, and HGF were significantly elevated in saliva from periodontitis and gingivitis patients in comparison to healthy individuals, whereas IL-34 was significantly lower in periodontitis compared to both healthy individuals and gingivitis patients. IL-34 increased significantly 3 months after treatment, while IL-1β and MMP-8 decreased 1 month after therapy. Additionally, periodontitis patients clustered in high and low levels of S100A8/A9, whereby those with high levels had more bleeding, deeper pockets, and higher S100A12.

CONCLUSIONS

Salivary levels of myeloid-related markers are altered in periodontitis and are partially modulated by periodontal treatment. Measuring S100A8/A9 in saliva may identify distinct groups of periodontitis patients.

Adjunctive efficacy of probiotics in the treatment of experimental peri-implant mucositis with mechanical and photodynamic therapy: a randomized, cross-over clinical trial

AIM

To evaluate the adjunctive clinical efficacy of probiotics in the treatment of peri-implant mucositis (p-iM) with professionally administered plaque removal (PAPR) and photodynamic therapy (PDT).

MATERIALS AND METHODS

Following p-iM induction, patients underwent PAPR + PDT and were randomly assigned to receive the professional and home-based administration of probiotics (Lactobacillus plantarum and Lactobacillus brevis) (test treatment) or placebo preparation (control treatment) according to a cross-over design. Clinical parameters were assessed at six sites for each implant before as well as at 2 and 6 weeks after professional treatment administration.

RESULTS

Twenty patients contributing one dental implant each were included. Immediately before treatment and at 6 weeks, the median number of sites with bleeding on probing (BoP+) sites per implant unit was 4 (3-6) and 2 (0-2) (p < 0.001), respectively, for test treatment, and 3.5 (2-4) and 2 (0-3) (p = 0.03), respectively, for control treatment. No significant difference in clinical outcomes was observed between treatment groups.

CONCLUSION

The combination of PAPR and PDT either alone or associated with probiotics determined a significant reduction in the number of BoP+ sites at 2 and 6 weeks around implants with p-iM. The adjunctive use of probiotics did not significantly enhance the clinical outcomes of PAPR + PDT.

Effects of triclosan on host response and microbial biomarkers during experimental gingivitis

AIM

This exploratory randomized, controlled clinical trial sought to evaluate anti-inflammatory and -microbial effects of triclosan during experimental gingivitis as assessed by host response biomarkers and biofilm microbial pathogens.

MATERIALS AND METHODS

Thirty participants were randomized to triclosan or control dentifrice groups who ceased homecare for 21 days in an experimental gingivitis (EG) protocol. Plaque and gingival indices and saliva, plaque, and gingival crevicular fluid (GCF) were assessed/collected at days 0, 14, 21 and 35. Levels and proportions of 40 bacterial species from plaque samples were determined using checkerboard DNA-DNA hybridization. Ten biomarkers associated with inflammation, matrix degradation, and host protection were measured from GCF and saliva and analysed using a multiplex array. Participants were stratified as "high" or "low" responders based on gingival index and GCF biomarkers and bacterial biofilm were combined to generate receiver operating characteristic curves and predict gingivitis susceptibility.

RESULTS

No differences in mean PI and GI values were observed between groups and non-significant trends of reduction of host response biomarkers with triclosan treatment. Triclosan significantly reduced levels of A. actinomycetemcomitans and P. gingivalis during induction of gingivitis.

CONCLUSIONS

Triclosan reduced microbial levels during gingivitis development (ClinicalTrials.gov NCT01799226).