Sinonasal Stent Coated with Slow-Release Varnish of Chlorhexidine Has Sustained Protection against Bacterial Biofilm Growth in the Sinonasal Cavity: An In Vitro Study

Silica nanoparticles containing nano-silver and chlorhexidine to suppress Porphyromonas gingivalis biofilm and modulate multispecies biofilms toward healthy tendency

Objectives

This research first investigated the effect of mesoporous silica nanoparticles (nMS) carrying chlorhexidine and silver (nMS-nAg-Chx) on periodontitis-related biofilms. This study aimed to investigate (1) the antibacterial activity on Porphyromonas gingivalis (P. gingivalis) biofilm; (2) the suppressing effect on virulence of P. gingivalis biofilm; (3) the regulating effect on periodontitis-related multispecies biofilm.

Methods

Silver nanoparticles (nAg) and chlorhexidine (Chx) were co-loaded into nMS to form nMS-nAg-Chx. Inhibitory zone test and minimum inhibitory concentration (MIC) against P. gingivalis were tested. Growth curves, crystal violet (CV) staining, live/dead staining and scanning electron microscopy (SEM) observation were performed. Biofilm virulence was assessed. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and Quantitative Real Time-PCR (qPCR) were performed to validate the activity and composition changes of multispecies biofilm (P. gingivalis, Streptococcus gordonii and Streptococcus sanguinis).

Results

nMS-nAg-Chx inhibited P. gingivalis biofilm dose-dependently (p<0.05), with MIC of 18.75 µg/mL. There were fewer live bacteria, less biomass and less virulence in nMS-nAg-Chx groups (p<0.05). nMS-nAg-Chx inhibited and modified periodontitis-related biofilms. The proportion of pathogenic bacteria decreased from 16.08 to 1.07% and that of helpful bacteria increased from 82.65 to 94.31% in 25 μg/mL nMS-nAg-Chx group for 72 h.

Conclusions

nMS-nAg-Chx inhibited P. gingivalis growth, decreased biofilm virulence and modulated periodontitis-related multispecies biofilms toward healthy tendency. pH-sensitive nMS-nAg-Chx inhibit the pathogens and regulate oral microecology, showing great potential in periodontitis adjunctive therapy.

Polyglactin 910 Meshes Coated with Sustained-Release Cannabigerol Varnish Inhibit Staphylococcus aureus Biofilm Formation and Macrophage Cytokine Secretion: An In Vitro Study

Synthetic surgical meshes are commonly used in abdominal wall reconstruction surgeries to strengthen a weak abdominal wall. Common mesh-related complications include local infection and inflammatory processes. Because cannabigerol (CBG) has both antibacterial and anti-inflammatory properties, we proposed that coating VICRYL (polyglactin 910) mesh with a sustained-release varnish (SRV) containing CBG would prevent these complications. We used an in vitro infection model with Staphylococcus aureus and an in vitro inflammation model of lipopolysaccharide (LPS)-stimulated macrophages. Meshes coated with either SRV-placebo or SRV-CBG were exposed daily to S. aureus in tryptic soy medium (TSB) or macrophage Dulbecco's modified eagle medium (DMEM). Bacterial growth and biofilm formation in the environment and on the meshes were assessed by changes in optical density, bacterial ATP content, metabolic activity, crystal violet staining, spinning disk confocal microscopy (SDCM), and high-resolution scanning electron microscopy (HR-SEM). The anti-inflammatory effect of the culture medium that was exposed daily to the coated meshes was analyzed by measuring the release of the cytokines IL-6 and IL-10 from LPS-stimulated RAW 264.7 macrophages with appropriate ELISA kits. Additionally, a cytotoxicity assay was performed on Vero epithelial cell lines. We observed that compared with SRV-placebo, the segments coated with SRV-CBG inhibited the bacterial growth of S. aureus in the mesh environment for 9 days by 86 ± 4% and prevented biofilm formation and metabolic activity in the surroundings for 9 days, with respective 70 ± 2% and 95 ± 0.2% reductions. The culture medium that was incubated with the SRV-CBG-coated mesh inhibited LPS-induced secretion of IL-6 and IL-10 from the RAW 264.7 macrophages for up to 6 days without affecting macrophage viability. A partial anti-inflammatory effect was also observed with SRV-placebo. The conditioned culture medium was not toxic to Vero epithelial cells, which had an IC₅₀ of 25 µg/mL for CBG. In conclusion, our data indicate a potential role of coating VICRYL mesh with SRV-CBG in preventing infection and inflammation in the initial period after surgery.

Biofilm in sino-nasal infectious diseases: the role nasal cytology in the diagnostic work up and therapeutic implications

BACKGROUD

Biofilm formation has been recently recognised as one of the most important etiopathological mechanisms underlying chronic rhinosinusitis (CRS) and its recalcitrance. In this context, nasal cytology (NC) has become an integral part of diagnostic work up of patients suffering from sino-nasal diseases, since it is an easy-to-apply, reproducible and non-invasive diagnostic tool that allows to assess both the nasal inflammatory infiltrate and the presence of biofilms on nasal mucosal surface, further orienting the therapeutic choices in case of infectious diseases for eradicating infections and biofilms. Nevertheless, biofilms are typically resistant to common antibiotic treatments and may trigger or maintain chronic inflammation. Hence, the importance of correctly detecting the presence of biofilm and identifying new effective treatments.

PURPOSE

The aim of this brief review is to better clarify the role of biofilm in the pathogenesis and recurrence of sino-nasal disorders and to highlight the role of nasal cytology (NC) in the rhino-allergologic diagnostic path and in the evaluation of the effectiveness of new treatments.

Sinonasal Stent Coated with Sustained-Release Varnish of Mometasone Furoate Inhibits Pro-Inflammatory Cytokine Release from Macrophages: An In Vitro Study

The aim of the study was to develop a sustained-release varnish (SRV) containing mometasone furoate (MMF) for sinonasal stents (SNS) to reduce mucosa inflammation in the sinonasal cavity. The SNS' segments coated with SRV-MMF or an SRV-placebo were incubated daily in a fresh DMEM at 37 °C for 20 days. The immunosuppressive activity of the collected DMEM supernatants was tested on the ability of mouse RAW 264.7 macrophages to secrete the cytokines' tumor necrosis factor α (TNFα) and interleukin (IL)-10 and IL-6 in response to lipopolysaccharide (LPS). The cytokine levels were determined by respective Enzyme-Linked Immunosorbent Assays (ELISAs). We found that the daily amount of MMF released from the coated SNS was sufficient to significantly inhibit LPS-induced IL-6 and IL-10 secretion from the macrophages up to days 14 and 17, respectively. SRV-MMF had, however, only a mild inhibitory effect on LPS-induced TNFα secretion as compared to the SRV-placebo-coated SNS. In conclusion, the coating of SNS with SRV-MMF provides a sustained delivery of MMF for at least 2 weeks, maintaining a level sufficient for inhibiting pro-inflammatory cytokine release. This technological platform is, therefore, expected to provide anti-inflammatory benefits during the postoperative healing period and may play a significant role in the future treatment of chronic rhinosinusitis.