Josiah Brown Poster Abstract


Kearny Chang
Dr. Flavia Pirih, Dr. Maria Galvan
Dr. Flavia Pirih, Dr. Maria Galvan, Gregory Chan
Effect of human oral microbiota exposed to e-cig smoke and their effect on periodontitis in a murine model
CTSI Summer Program

Introduction: The impact of electronic cigarettes (‘e-cigs’) on gingival inflammation and periodontal diseases is currently unknown. In contrast, the impact of traditional tobacco on oral health has been extensively studied and its use recognized as a significant risk factor for progression of periodontal diseases. E-cigs contain toxic chemicals, including nicotine which may pose risks to users. The goal of this study was to evaluate the effect of e-cig smoke on gingival inflammation and bone loss in a murine model of periodontitis.

Materials and methods: Saliva samples from 3 human subjects (“D”, “L”, “A”) and cultured in David Pride’s Lab in San Diego. Samples were cultured in either ECV-exposed (electronic cigarette vapor) specific growth medium (50% propylene glycol, 50% vegetable glycerin, 24 mg/mL nicotine) or non EVC-exposed medium. Non-viable microbes were extracted from the biofilm from each medium. Mice were separated into control (endotoxin free water), biofilm e-cig (ECV exposed microbes) and biofilm non e-cig (non-ECV exposed microbes) groups and injected accordingly. Injections were performed between the 1st and 2nd molars on both sides of the maxillae, 0.2 ul/injection twice a week for six weeks. Following sacrifice, microCT and bone linear analysis were performed to calculate a mean value of linear bone loss for each mouse, as defined as the distance from the CEJ to the alveolar bone crest between 1st and 2nd maxillary molars and palatal of 2nd maxillary molars.

Results: There was no significant difference in linear bone loss between biofilm e-cig groups and non e-cig groups. Moreover, none of the biofilm e-cig groups showed linear bone loss compared to control while two biofilm non e-cig groups did. Clinical images show increased gingival inflammation in both of the biofilm e-cig and non e-cig groups compared to control.

Discussion: The use of human saliva as a method for bacterial colonization in mice has several limitations due to the variations in the species colonization disease model. In addition, utilizing ECV-exposed human saliva biofilm specific growth medium as a method to study the effects of e-cig in mice’s periodontal health was not been proven to be effective. Future directions could include comparing between nicotine and non-nicotine containing e-cig vapors, as well as the differences between e-cig flavors, as some flavorings have increased toxicity. Flow cytometry can also be utilized to future characterization of the immune response.