Characterization of a novel antibiofilm effect of nitric oxide-releasing aspirin (NCX-4040) on Candida albicans isolates from denture stomatitis patients

PLoS One. 2017 May 11;12(5):e0176755. doi: 10.1371/journal.pone.0176755. eCollection 2017.

Abstract

Candida albicans biofilms play a key role in denture stomatitis, one of the most common oral pathologies in elderly people. Because biofilms are highly resistant to antifungals, new pharmacological strategies are needed. Aspirin and nitric oxide-donor molecules have both shown antibiofilm effects on C. albicans, making them promising candidates for treatment. In this study, we evaluated the antifungal/antibiofilm effect of a nitric-oxide releasing aspirin (NO-ASA) on C. albicans isolates from denture stomatitis patients in vitro. Disk diffusion assays showed that while NO-ASA had no antifungal effect, the drug potentiated fluconazole inhibition zone diameters, increasing the effect of fluconazole by 20-30% (p<0.05). The effect of NO-ASA on the morphogenesis of C. albicans was evaluated using light microscopy after inducing hyphae formation. For all clinical strains assayed, 125 μM NO-ASA significantly decreased the number of filamentous cells present (p<0.01). Adhesion to abiotic surfaces, a critical event for biofilm formation, was evaluated in 96-well polystyrene plates using crystal violet assay; 125 μM NO-ASA significantly inhibited adhesion. Biofilms were observed with scanning electron microscopy (SEM) and quantified using XTT reduction assay. NO-ASA decreased biofilm formation (IC50 ranging from 300 μM to 700 μM), consistent with SEM findings of altered biofilm microarchitecture. PGE2 and carboxy-PTIO (an NO scavenger) both blocked the antibiofilm effects of NO-ASA, suggesting that the efficacy of NO-ASA may be associated with both inhibition of PGE2 synthesis and release of NO. NO-ASA is a promising novel antibiofilm agent for treating fluconazole-resistant strains of C. albicans.

MeSH terms

  • Antifungal Agents / pharmacology
  • Antifungal Agents / therapeutic use
  • Aspirin / analogs & derivatives*
  • Aspirin / pharmacology
  • Aspirin / therapeutic use
  • Bacterial Adhesion / drug effects
  • Biofilms / drug effects*
  • Candida albicans / drug effects
  • Candida albicans / isolation & purification*
  • Candida albicans / ultrastructure
  • Dinoprostone / metabolism
  • Drug Resistance, Fungal / drug effects
  • Fluconazole / pharmacology
  • Fluconazole / therapeutic use
  • Free Radical Scavengers / pharmacology
  • Humans
  • Inhibitory Concentration 50
  • Microbial Viability / drug effects
  • Nitro Compounds / pharmacology*
  • Nitro Compounds / therapeutic use
  • Stomatitis, Denture / drug therapy
  • Stomatitis, Denture / microbiology*

Substances

  • Antifungal Agents
  • Free Radical Scavengers
  • NCX 4040
  • Nitro Compounds
  • Fluconazole
  • nitroaspirin
  • Dinoprostone
  • Aspirin

Grants and funding

This work was supported by Fondo Nacional de Desarrollo Científico y Tecnológico, proyecto FONDECYT (grant number 11140227, AMB) (http://www.conicyt.cl/fondecyt/); Vicerrectoría de Investigación y Desarrollo (VID), Universidad de Chile, project U-INICIA (grant number 2014-82383, AMB) (http://www.uchile.cl/portal/investigacion/5077/presentacion); and Vicerrectoría de Investigación y Desarrollo (VID), Universidad de Chile, project U-redes (grant number URED-2014-007, AMB, RFR, JAJ, BU). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.