Metabolomic profiling of oral bacteria in patients with rheumatoid arthritis and periodontitis / Foong Su Wen

Foong , Su Wen (2024) Metabolomic profiling of oral bacteria in patients with rheumatoid arthritis and periodontitis / Foong Su Wen. Masters thesis, Universiti Malaya.

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Abstract

Background and Objective. Rheumatoid arthritis (RA) and periodontitis (PD) are both chronic inflammatory diseases, and they share similar pathological features. Dental plaque harbours many species of bacteria and the dynamic, complex host-microbiome interaction play a significant role in initiating periodontal disease. Several oral bacteria have been shown to influence the progression of rheumatoid arthritis. Nevertheless, the underlying mechanism has become the focus of further investigation. Bacteria interact differently to ensure adaptation and reorganisation periodically. Metabolites which are the end stage of the biological system could provide insights into the functions of the oral microbiome. Therefore, the identification of the expressed metabolites in dental plaque, particularly in the early stage of rheumatoid arthritis may present the opportunity for more efficient management of RA. The aim of the present study is to profile metabolites in dental plaque in relation to RA and PD and correlate the differentially expressed metabolites with clinical parameters. Materials and methods. This pilot study consisted of 27 participants who were categorised into different groups based on their diagnosis. The groups included early RA with periodontitis (ERAPD), early RA without periodontitis (ERANPD), chronic RA with periodontitis (CRAPD), chronic RA without periodontitis (CRANPD), non-RA with periodontitis (NRAPD) and non-RA without periodontitis (NRANPD). Periodontal assessment, PPD, CAL, VPI and GBI were evaluated while DAS-28 and ESR were extracted from the electronic medical records. Subsequently, dental plaque samples were collected and metabolites were extracted and analysed using liquid chromatography quadruple time-of-flight mass spectrometry (LC-Q-ToF-MS) to profile the metabolites. Results. A total of 27 plaque samples from, ERAPD (3), ERANPD (4), CRAPD (5), CRANPD (5), NRAPD (5), and NRANPD (5) were analysed. 1065 different metabolites were detected in ERANPD in comparison to the NRANPD. A notable variation of metabolite expression was also observed between CRANPD in comparison to ERANPD with a total of 769 metabolites. Conversely, number of expressed metabolites were lower in CRAPD when compared to CRANPD group, as well as in the ERAPD compared to ERANPD. Bivariate correlation analysis revealed strong correlation with statistically significant difference (p<0.05) between nine metabolites and clinical parameters. Conclusion. The metabolites observed in ERA exhibited a wide range of diversity, with a majority showing upregulation. This finding indicates a potential involvement of nine metabolites, His-his, 5-Aminopentanoic acid, 12-hydroxy-10-octadecynoic acid, N-Acetyl-b-glucosaminylamine, 4-Isopropylbenzoic acid, Stigmatellin Y, Saccharopines, N-Cyclohexanecarbonylpentadecylamine, and Anandamide (20:l, n-9) in pathogenesis of RA and PD.

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