Efficacy of Salivary Antimicrobial Peptide Histatin-5 Against Experimental Denture Stomatitis

Objectives: Denture stomatitis (DS), an oral condition prevalent in up to 70% of denture wearers is caused by Candida albicans, an opportunistic fungal species commonly colonizing oral mucosal surfaces. However, in the oral cavity saliva plays an important role in protection against microbial infection. Specifically, innate host salivary antimicrobial peptides (AMPs) are considered to play a key role in this process. We recently developed a mouse model of oral candidiasis to demonstrate the potency of the anti-candidal AMP histatin-5 (Hst-5) in preventing development of oral candidiasis. In this current study, in vitro experiments were designed to demonstrate a similar efficacy for Hst-5 in preventing C. albicans adherence and colonization of denture material. Further, a rat denture model was developed to demonstrate the potential application of Hst-5 for the prevention and/or treatment of DS.

Methods: JET acrylic discs pre-conditioned with saliva were incubated with C. albicans cell suspension in the presence and absence of Hst-5 under various experimental conditions. Following rinsing, adherent cells were recovered by sonication, diluted and plated on fungal media for quantification of colony forming units (CFUs) in order to assess fungal burden. The rat denture model was successfully tested for suitability as a model to study the development and progression of DS.

Results: Hst-5 treatment of discs resulted in significant decrease (p<0.05) in level of C. albicans adherence and subsequent colonization. Protective effect of Hst-5 was proportional to its concentration and inversely proportional to C. albicans cell density.

Conclusions: These in vitro findings demonstrate the efficaciousness of Hst-5 in preventing colonization of denture material attributing a therapeutic potential for the prevention of oral prosthesis. Currently, studies to demonstrate this potential in vivo are underway using the rat model. This is the first study exploring the application of Hst-5 using a combination of in vitro and animal studies.