Periodontal diseases and its association with disease activity in ankylosing spondylitis/SpA: A systematic review

No genetic causal association between periodontitis and ankylosing spondylitis: a bidirectional two-sample mendelian randomization analysis

BACKGROUND

Observational studies that reveal an association between periodontitis (PD) and ankylosing spondylitis (AS) exist. However, observational research is prone to reverse causality and confounding factors, which make it challenging to infer cause-and-effect relationships. We conducted a two-sample Mendelian randomization (MR) study to examine the causal relationship between the genetic prediction of PD and AS.

METHODS

In our study, single-nucleotide polymorphisms (SNPs) were defined as instrumental variables (IVs). The genetic association with PD came from the Gene-Lifestyle Interactions and Dental Endpoints (GLIDE) consortium, wherein 17353 cases of European ancestry and 28210 controls of European ancestry were included in this study. The genetic association with AS from the Neale Laboratory Consortium included 337,159 individuals from the United Kingdom, with 968 cases and 336,191 controls. MR analysis was mainly performed using the inverse-variance weighted (IVW) method. In addition, the robustness of the study findings was assessed using sensitivity, pleiotropy, and heterogeneity analyses.

RESULTS

Eighteen independent SNPs with P-values significantly smaller than 1 × 10- 5 were used as IV SNPs for PD, while 39 independent SNPs with P-values significantly smaller than 1 × 10- 5 were used as IV SNPs for AS. The results of the IVW method revealed no causal association between PD and AS (odds ratio = 1.00, 95% confidence interval: 0.99953 to 1.00067, P = 0.72). The MR-Egger method did not support the causal association between PD and AS. It is unlikely that horizontal pleiotropy distorts causal estimates based on sensitivity analysis. No significant heterogeneity was observed in the Q test. The ''leave-one-out'' analysis demonstrated that the robustness of our results was unaffected by eliminating any of the IVs. Likewise, no significant causative effect for AS on PD was observed in the inverse MR analysis.

CONCLUSIONS

The study results do not support shared heritability or a causal association between PD and AS.

Tooth Loss Is Associated with Disease-Related Parameters in Patients with Rheumatoid Arthritis and Ankylosing Spondylitis-A Cross-Sectional Study

Background: The aim of this cross-sectional study was to investigate potential associations between periodontal inflamed surface area (PISA) and tooth loss with disease-related parameters in patients with rheumatoid arthritis (RA) and ankylosing spondylitis (AS). Methods: Patients who attended the Department of Nephrology and Rheumatology, University Medical Centre Goettingen, Germany, were included. The oral examination comprised the detection of the number of remaining teeth and periodontal condition based on staging and grading matrix. Based on periodontal pockets with positive bleeding on probing, the periodontal inflamed surface area (PISA) was determined. Disease related parameters were extracted from the patients’ records. Results: In total, 101 (RA) and 32 participants (AS) were included. Patients with RA had 22.85 ± 4.26 and AS patients 24.34 ± 5.47 remaining teeth (p < 0.01). Periodontitis stage III and IV was present in 91% (RA) and 81.2% (AS) of patients (p = 0.04). Associations between PISA and disease-related parameters were not found in both groups (p > 0.05). In RA, a higher age (p < 0.01), C-reactive protein (p = 0.02), disease activity (p < 0.01) and prednisolone intake (p < 0.01) were associated with fewer remaining teeth. In AS, a higher age (p = 0.02) and increased Bath Ankylosing Spondylitis Metrology Index (p = 0.02) were associated with a lower number of remaining teeth. Conclusions: Tooth loss is associated with disease activity, especially in RA individuals. Dental care to prevent tooth loss might be recommendable to positively influence oral health condition and disease activity in RA and SA patients.

The Salivary Microbiota, Cytokines, and Metabolome in Patients with Ankylosing Spondylitis Are Altered and More Proinflammatory than Those in Healthy Controls

The pathogenesis of ankylosing spondylitis (AS) remains unclear but appears to be associated with heredity and the environment. The mouth links the external environment to the gut and lungs. In the present study, compared to that observed in healthy controls (HCs), AS saliva was depleted of Bacilli such as Streptococcus, enriched with Clostridia such as Veillonellaceae, and enriched with opportunistic pathogens from Proteobacteria such as Brucella spp. and Campylobacter concisus. AS saliva was enriched with 16 cytokines related to inflammation, such as soluble IL-6 receptor α (sIL-6Rα), interleukin 2 (IL-2), IL-10, IL-11, IL-12p40, IL-12p70, IL-20, IL-26, IL-27, IL-28A, IL-29, alpha 2 interferon (IFN-α2), IFN-β, and matrix metalloproteinase 3 (MMP-3). AS saliva was also enriched with hazardous compounds, such as cadaverine and putrescine. AS-altered salivary bacteria, compounds, and cytokines are closely linked with disease indicators. Oral cleaning reduced the levels of proinflammatory cytokines and hazardous compounds in AS saliva compared with HC saliva. AS saliva induced the production of more proinflammatory cytokines, such as IL-12p70 and IL-8, by THP-1 monocyte-derived macrophages, than did HC saliva. The results highlight the importance of salivary microbes, cytokines, and compounds in the development and treatment of AS and provide new ideas for the pathogenesis and treatment of AS.

IMPORTANCE Ankylosing spondylitis (AS) affects as much as 0.32% of the population in some districts and causes work disability in one-third of these patients. Microbes are considered to play important roles in AS pathogenesis, and the mouth links the environment to the lungs and the gut. Our results showed that opportunistic pathogens such as Brucella and Campylobacter are enriched in the saliva of AS patients with ankylosing spondylitis. In addition, proinflammatory cytokines and hazardous materials such as putrescine were also enriched in the saliva of AS patients.[AQ1 sentence edit] Interestingly, the opportunistic pathogens and hazardous materials detected in the saliva of AS patients were associated with disease indexes. The saliva of AS patients was shown to induce immune cells to secrete proinflammatory cytokines in vitro. Reducing the levels of salivary microbes can significantly reduce the hazardous materials present in the saliva of AS patients. Our results provide a new perspective on the potential role of salivary microbes, cytokines, and hazardous compounds in the pathogenesis and treatment of AS.