Periodontal Disease (PD) is shown to be associated with an increased the risk of a number of systemic diseases - including atherosclerosis. We are investigating a possible causal relationship in a young population of individuals with PD (ages 20-30) to determine if they show early signs of atherosclerosis. Using powerful new culture-independent molecular approaches based on pyrosequencing technology, we are conducting a comprehensive metagenomic analysis to identify, classify, and quantify bacterial species associated PD and atherosclerosis (both pre- and post- treatment for PD). This survey of microbial diversity is expected to cover between 300,000-500,000 16S sequences for 300 samples from 40 patients. The bioinformatics pipeline will include

1) databasing data sets of unique 100-250-base 16SrRNA sequences per species, 2) sequence alignment and phylogenetic analysis, and 3) computing distance metrics for differences between microbial communities (samples) at different stages of PD and with or without changes in brachial artery flow dynamics. Multivariate analyses, such as Principle Coordinates Analysis (PCoA), will be used to show the distribution of 16S community samples. Subsequently, functional annotation of the genes combined with relative abundance data for each species will allow for the prediction of important functional relationships among potential subnetworks of species that support the persistence of PD and that could be involved in the mechanism of action leading to atherosclerosis. Ultimately, this knowledge could be used to develop an effective probiotic treatment for PD.