PPM2-0216-170012

Non-communicable diseases (NCDs) account for 69% of death in Qatar, according to the World Health Organization and are one of the most significant threats to the healthcare system. Unlike infectious/ communicable diseases that can be either transient, latent, or result in rapid death if severe, NCDs are often chronic and maintained over a longer duration of life. The earliest these diseases are diagnosed the more likely the proper medical attention will be achieved. Early detection is vital and essential for clinical treatment of a disease; however, the use of clinical diagnostics is not yet fully developed due to various limitations. Those include the lack of specific biomarkers associated with diseases, the high cost of the diagnostics methods available and the complicated platforms, which are not appealing to clinical care personnel. Saliva is a biofluid containing secretions from the salivary glands, oral mucosa cells, blood and gingival fluid. Similar to blood, serum and other body fluids, saliva contains DNA, RNA, proteins, metabolites, exosomes and microbiota. Saliva plays an important role in maintaining oral health and homeostasis, in addition to its role in maintaining the function of the upper gastrointestinal tract. Salivary microbiome plays an important role in maintaining oral and systemic health, primarily by inhibiting colonization by pathogens. The salivary microbiome can be different in various diseases such as oral disease, diabetes, or cardiovascular disease, as well as in diverse ethnic groups partly due to the type of food intake and eating habits. Few studies have previously described the salivary ‘omics’ constituents but none has been done on an Arab or Qatari population. The ongoing Qatar Genome project concluded the sequencing of more than 3000 Qatari nationals’ whole genomes in its pilot phase and collected clinical and phenotypic data from those participants. The goal is to input that data into the National Health Service electronic medical records in order to leverage a broader delivery of healthcare for the Qatari population and pave the path towards personalized medicine. With the availability of saliva samples collected from the volunteers enrolled in the Qatar genome project, there is an excellent opportunity to study the feasibility of using saliva samples for developing a diagnostics tool that is non-invasive, simple and affordable. Saliva microbiome spectrum and host biomarkers analysis can provide a noninvasive feedback of disease progression and treatment. Changes in saliva components including microbiome, metabolome or proteome composition, whether associated with infectious, physiological or pathological events, may accompany and even precede the onset of clinical symptoms and predict adverse outcomes. The introduction in recent years of groundbreaking high-throughput omics technologies including metagenomics, proteomics and metabolomics has made it possible to monitor the composition and changes of microbiome, proteome and metabolome in human subjects with unprecedented depth/resolution allowing the discovery of various biomarkers associated with disease. As the association between the biomarkers levels and the personal health status becomes more evident, omics research is now considered fundamental to the progress of disease diagnostics and therapeutics in addition to the advancement of personalized medicine for an optimal health care. We hypothesize that salivary microbiome, metabolome and proteome perturbations precede adverse events during diseases, and that those perturbations can be detected using omics approaches. In this study, we propose to use metagenomics sequencing of the saliva samples to provide an in-depth knowledge of the salivary microbiome across 2000 Qatar Genome project participants in order to understand the composition of the salivary microbiome and proteome and correlate it with health conditions, diet and nutrition. This project aims to establish a reference salivary microbiome and a baseline salivary proteome for healthy individuals in Qatar. In addition, it could provide a proof of principle of the feasibility of use of saliva samples to develop a diagnostics tool that can be used to predict or monitor some pathological conditions as well as disease onset or progression. Specific aims include: 1- To profile the salivary microbiome in 2000 Qatari volunteers using 16S rRNA gene sequencing. 2- To assess the dietary habits, nutritional status, and cardiovascular risk score using data collected during the Qatar Genome Project pilot phase. 3- To analyze the salivary microbiome data and correlate it with the phenotypic, clinical and nutritional data. 4- To identify biomarkers that precede or correlate with NCDs, to establish baseline values in healthy individuals and to compare those biomarkers between saliva and plasma.