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ABSTRACT
Background: Non-human primates appear to represent the most faithful model of human disease, but to date the oral microbiome in macaques has not been fully characterized using next-generation sequencing.
Objective: In the present study, we characterized the clinical and microbiological features of naturally occurring periodontitis in non-human primates (Macaca mulatta).
Design: Clinical parameters of periodontitis including probing pocket depth (PD) and bleeding on probing (BOP) were measured in 40 adult macaques (7-22 yrs), at six sites per tooth. Subgingival plaque was collected from diseased and healthy sites, and subjected to 16S rDNA sequencing and identification at the species or higher taxon level.
Results: All macaques had mild periodontitis at minimum, with numerous sites of PD ≥ 4 mm and BOP. A subset (14/40) had moderate-severe disease, with > 2 sites with PD ≥ 5mm, deeper mean PD, and more BOP. Animals with mild vs moderate-severe disease were identical in age, suggesting genetic heterogeneity. 16S rDNA sequencing revealed that all macaques had species that were identical to those in humans or closely related to human counterparts, including Porphyromonas gingivalis which was present in all animals. Diseased and healthy sites harboured distinct microbiomes; however there were no significant differences in the microbiomes in moderate-severe vs. mild periodontitis.
Conclusions: Naturally occurring periodontitis in older macaques closely resembles human adult periodontitis, thus validating a useful model to evaluate novel anti-microbial therapies.
ARTICLE HISTORY
Received 9 June 2017
Accepted 8 November 2017
KEYWORDS
oral microbiome; macaques; naturally occurring periodontitis; next-generation sequencing; 16S rRNA
Introduction
Periodontitis is a microbiome-driven disease that mainly affects older individuals and results in chronic immune activation, inflammation, soft tissue and bone destruction, and ultimately tooth loss. Accumulating evidence indicates that periodontitis contributes to the risk and severity of systemic conditions in which inflammation plays a key role, including type 2 diabetes, atherosclerosis and cardiovascular disease, pre-term birth, arthritis, and certain cancers [1-3]. The current preventive regimens and treatments for periodontitis are focused on removal of bacterial biofilms through oral hygiene measures and surgical procedures. Such approaches are sometimes ineffective, and are labour intensive, costly, and difficult to implement from a public health perspective.
Given the microbial aetiology of periodontitis, new anti-microbial agents and vaccines represent a logical strategy for disease prevention and to augment...