Thu0066 does Porphyromonas Gingivallis Modulate Gut Microbiome Resulting in Aggravation of Disease Activity in Rheumatoid Arthritis?

Abstract

Background:Oral Porphyromonas gingivalis (Pg) infection in rheumatoid arthritis (RA) model revealed aggravation of arthritis, dysbiosis and higher serum LPS (1). We reported that IgA/IgG antibody against Pg-LPS ratio among the patients with RA related to disease marker levels and disease activities (2). However, there are still few reports related to Gut-Oral axis.Objectives:Firstly, how total intestinal bacteria, well-known 5 species of gut bacteria behave in relation to disease activities and markers. Secondly, how infection by Pg aggravate RA in relation to microflora, disease activities and markers.Methods:Eighty-seven RA patients with inadequate response to conventional synthetic DMARDs were evaluated. Age: 68.1±8.7 years, female (%): 79.3, disease duration: 136±91 months, DAS28-ESR: 4.68±0.98. Fecal bacteria numbers of total bacteria, Bifidobacterium, Lactobacillus, E. coli, Bacteroides and Staphylococcus were determined by PCR analysis. Fecal and serum LPS levels were measured by LAL assay. Serum endotoxin neutralizing activity (ENC) was determined along with RA disease activity and markers measurement. Infection of Pg was proofed by IgG and IgA anti-LPS antibody measurement. The statistical relationships between variables were analyzed by Spearman’s non-parametric rank correlation analysis and expressed as Spearman’s rank correlation coefficient “ρ”.Results:At first, we could neglect background effects as duration, methotrexate dose for measuring total or each bacterial number (data not shown). As shown in Figure 1, total bacteria only showed positive correlation with IL-6 levels (ρ= 0.230, p = 0.034), however inversely correlated with disease activities such as pVAS (ρ= -0.223, p = 0.038) and Pain VAS (ρ= -0.260, p = 0.015). While no significant relationship was observed between the numbers of each of 5 species of bacteria and the disease activities and makers except Bifidobacterium. In contrast, LPS-related markers showed positive correlation with disease activities and markers. Among LPS-related biomarker values, serum LBP levels mainly correlated with most of RA biomarker-ESR (ρ= 0.497, p <0.0001), CRP (ρ= 0.697, p <0.0001), MMP3 (ρ= 0.546, p <0.0001) and so on. Fecal LPS level was shown significant positive correlation with disease activities, however almost no correlation was observed in serum LPS level. IgA anti-LPS antibody levels to Pg, resulted in inverse correlation with total bacteria (ρ= -0.441, p<0.0001), Lactobacillus (ρ= -0.224, p=0.037), Bacteroides (ρ = -0.200, p = 0.064) and E. coli (ρ= -0.260, p = 0.015), moreover, positive correlation with serum LPS (ρ= 0.284, p = 0.008) and LBP (ρ= 0.247, p = 0.021) and inverse correlation with ENC (ρ = -0.321, p = 0.002) were found. On the other hand, IgG anti-Pg-LPS antibody levels which reflect systemic infection, inversely correlated SDAI (ρ = -0.308, p = 0.004), PainVAS (ρ = -0.433, p < 0.0001), and so on.Conclusion:Serum LBP highly associated with RA activity and markers, which suggests bacterial LPS as roles in triggering and perpetuating disease activity in RA. In contrast, IgA anti-Pg-LPS, IgG anti-Pg-LPS antibody reflecting infection of Pg, negatively associated with intestinal total bacteria (ρ=-0.4405, p<0.0001), RA disease activities, respectively. These results may show a possible oral -gut relationship resulting in aggravation of disease activity in RA.Disclosure of interest:None declaredReferences:[1]Sato K, Takahashi N, Kato T et al. Aggravation of collagen induced arthritis by orally administered Porphyromonas gingivalis through modulation of the gut microbiota and gut immune system. Sci Rep 2017; 7:6955.[2]Kuniaki Terato, Takaki Waritani, Richio Fukai et al. Contribution of bacterial pathogens to evoking serological disease markers and aggravating disease activity in rheumatoid arthritis. PloS One. 2018;13(2): e0190588.Disclosure of Interests:None declared

Comment on: ‘Metagenome-wide association study of gut microbiome revealed novel aetiology of rheumatoid arthritis in the Japanese population’ by Kishikawaet al

“…Another microbiome from oral cavity, Pg is also considered to play a pathogenic role in RA since Pg peptidylarginine deiminase is implicated in the autoimmunity of RA by creating mimic antigen, circular citrullinated peptide (CCP), by autocitrullination 5. Interestingly, anti- Pg -LPS antibody associated with RA clinical indices and biomarker in our study with established RA, suggesting the role for continuation of RA inflammation 9. These data by Maeda and ours might show the possibility that multiple Prevotella spp.…”

“…We previously investigated the relationship between RA disease activity using activity indices and biomarkers; the total bacterial counts and the counts of five well-known gut bacteria species; LPS-related biomarkers and IgG and IgA anti- Pg -LPS antibodies in 87 patients with established RA showing inadequate responses to conventional synthetic disease-modifying antirheumatic drugs or exhibiting severe complications 9. (online supplementary table 1)SP110.1136/annrheumdis-2020-217808.supp1…”

“…Bacterial DNA extracted from individual faecal samples was subjected to real time-PCR using the group-specific or species-specific primers. The methods used to analyse LPS-biomarkers and anti- Pg -LPS antibodies are described in references 5 9 12. Patient age, sex, disease duration, treatment with MTX, drinking habits and smoking habits showed little effect on bacterial counts (data not shown).Top values are the slopes of the correlation (correlation coefficient “ρ”) and bottom values are the p values determined by Spearman’s non-parametric rank correlation analysis.…”