Soluble neuropilin-1 in gingival crevicular fluid is associated with rheumatoid arthritis: An exploratory case-control study

Abstract Background To explore the soluble Neuropilin-1 (sNRP-1) concentrations in gingival crevicular fluid (GCF) and the periodontal clinical status of patients with Rheumatoid Arthritis (RA). Materials and methods We conducted an exploratory study with 40 study participants, 20 with RA, and 20 healthy controls. Clinical and periodontal data were recorded, and GCF samples were obtained. sNRP-1 levels in GCF were determined by ELISA assay. Descriptive statistics, Mann–Whitney U test, Unpaired t-test, logistic regression model, and Area Under Receiver Operating Characteristic Curve (AUC-ROC) were made to explore the diagnostic performance accuracy. Results RA patients had significantly higher levels of sNRP-1 in GCF (p = 0.0447). The median levels of GCF-sNRP-1 were 208.85 pg/μl (IQR 131.03) in the RA group compared to 81.46 pg/μl (IQR 163.73) in the control group. We observed an association between the GCF-sNRP-1 concentrations and the RA diagnosis (OR:1.009; CI 1.00–1.001; p = 0.047). The diagnosis of chronic periodontitis was also associated with RA (OR: 6.9; CI 1.52–31.37; p = 0.012). Moreover, the AUC-ROC of GCF-sNRP-1 concentrations combined with periodontal clinical parameters such as periodontal probing depth and periodontal inflamed surface area was 0.80. Conclusion This exploratory case-control study shows that RA patients had significantly higher levels of sNRP-1 in GCF. New longitudinal studies are necessary to evaluate the role of NRP-1 in periodontal tissues and consider it an oral biomarker with clinical value in RA.