Subgingival microbiome of rheumatoid arthritis patients in relation to their disease status and periodontal health Original paper
Researched by:
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Kimberly Eyer
ID
Kimberly Eyer
Kimberly Eyer, a Registered Nurse with 30 years of nursing experience across diverse settings, including Home Health, ICU, Operating Room Nursing, and Research. Her roles have encompassed Operating Room Nurse, RN First Assistant, and Acting Director of a Same Day Surgery Center. Her specialty areas include Adult Cardiac Surgery, Congenital Cardiac Surgery, Vascular Surgery, and Neurosurgery.
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Rheumatoid Arthritis
Rheumatoid Arthritis
OverviewRheumatoid arthritis (RA) is a systemic autoimmune disease marked by chronic joint inflammation, synovitis, and bone erosion, driven by Treg/Th17 imbalance, excessive IL-17, TNF-α, and IL-1 production, and macrophage activation. Emerging evidence links microbial dysbiosis and heavy metal exposure to RA, [1][2] with gut microbiota influencing autoimmune activation via Toll-like receptor (TLR) signaling, inflammasome activation, […]
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Kimberly Eyer
Researched by:
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Kimberly Eyer
ID
Kimberly Eyer
Microbiome Signatures identifies and validates condition-specific microbiome shifts and interventions to accelerate clinical translation. Our multidisciplinary team supports clinicians, researchers, and innovators in turning microbiome science into actionable medicine.
Kimberly Eyer
Location
Norway
Sample Site
Saliva
Subgingival dental plaque
Species
Homo sapiens
What was studied?
This study analyzed the subgingival microbiome in patients with chronic rheumatoid arthritis (RA) to explore how oral bacterial communities correlate with RA disease activity and periodontal health status. Using 16S rDNA sequencing and qPCR, researchers characterized bacterial diversity and composition in subgingival plaque samples, seeking associations between microbial profiles and RA-related clinical parameters including medication use, disease severity, and lifestyle factors such as smoking.
Who was studied?
The study population included 78 RA outpatients (73% female, average age 57), all of whom met the 2010 ACR/EULAR classification criteria for RA. Subjects were excluded if they had diabetes, malignancy, Sjögren’s syndrome, or had taken antibiotics in the three months prior. Clinical periodontal exams were conducted, and extensive RA clinical data were obtained from medical records. Microbial samples were collected from the deepest interproximal subgingival sites, and sequencing was conducted to assess microbial community structure.
What were the most important findings?
The subgingival microbiome in RA patients was influenced by RA disease activity, smoking status, prednisolone use, and periodontal parameters such as probing depth and bleeding on probing. Two distinct microbial community types were identified. Patients with active RA exhibited lower microbial diversity and a higher abundance of facultative anaerobes such as Streptococcus and Veillonella, especially if they were on prednisolone. In contrast, those in remission—particularly current smokers—had a dysbiotic profile enriched with anaerobes like Fusobacterium, Treponema, and Fretibacterium. These shifts indicate that systemic inflammation and immunosuppressive therapies reshape local microbial communities. Interestingly, only 14% of samples were positive for Porphyromonas gingivalis, questioning its exclusivity in RA pathogenesis. Smoking significantly altered microbial composition, promoting pathogenic anaerobes and correlating with increased periodontal destruction.
| Variable | Key Findings | Major Microbial Associations (MMAs) | Clinical Implications |
|---|---|---|---|
| RA Activity | Lower diversity in active RA; prednisolone use shapes microbial balance | Streptococcus, Veillonella, Actinomyces | Therapy may influence microbiome health and serve as indirect periodontal protection |
| Smoking | Smokers showed more pathogenic anaerobes, higher probing depth | Fusobacterium, Treponema, Fretibacterium | Smoking cessation critical for oral and systemic immune stability |
| Periodontal Probing Depth (PD) | Deeper pockets associated with strict anaerobes | Treponema denticola, Tannerella forsythia, Fretibacterium | Specific taxa may indicate localized periodontal pathology and systemic immune link |
| Prednisolone Use | Use associated with microbial profiles skewing toward aerobic and facultative anaerobes | Corynebacterium, Neisseria, Veillonella | Anti-inflammatory medications may reduce dysbiosis through systemic inflammation control |
| Community Type Stratification (CT1/CT2) | CT1 linked to inflammation and dysbiosis; CT2 linked to higher RA activity but better oral health | CT1: Fusobacterium, Prevotella, Treponema; CT2: Streptococcus, Corynebacterium | Microbial typing could inform personalized RA and periodontal care pathways |
What are the greatest implications of this study?
The findings emphasize that the subgingival microbiome in RA is shaped by a complex interplay of disease activity, treatment, and lifestyle. The distinct microbial community types (CT1 and CT2) linked to clinical subgroups suggest a potential stratification tool for identifying RA patients at elevated risk for periodontal complications or with immunologically modulated oral niches. Importantly, anti-inflammatory therapy, particularly prednisolone, was associated with a shift toward a healthier microbiome, indicating that immunomodulatory treatment indirectly supports oral microbial stability. The identification of specific taxa such as Fretibacterium, Treponema, Corynebacterium, and Actinomyces as major microbial associations (MMAs) provides potential microbial biomarkers for disease monitoring and targets for adjunctive therapies. The study supports integrating oral microbial profiling into RA patient care, with implications for personalized interventions and the design of microbiome-targeted therapies.