Background/Purpose: Sjögren’s syndrome (SJS) is a chronic autoimmune disorder with lymphocytic infiltration of exocrine and non-exocrine epithelia, in which epithelial cells play a critical role in the initiation and amplification of inflammatory processes. Syndecan-1 (sdc-1), a transmembrane heparan sulfate proteoglycan, is predominantly expressed on epithelial cells and functions primarily as coreceptors through the binding of heparan sulfate chain to a wide range of ligands, such as extracellular matrix components, cytokines, and chemokines. Although ectodomain of sdc-1 is constitutively shed, ectodomain shedding is accelerated in response to diverse pathophysiological conditions and may be related with pathogenesis of SJS. In this study, we investigated the association of sdc-1 levels in plasma and saliva with functional parameters of salivary glands in SJS patients.

Methods: Unstimulated and stimulated salivary flow rates and sdc-1 levels of saliva and plasma were measured in 37 SJS patients and 34 normal controls (NC). We assessed the disease activity indexes, including ESSDAI and ESSPRI, and performed salivary gland scan and serologic markers in SJS patients.

Results: ESSDAI and ESSPRI scores of SJS patients were 3.78 ± 3.33 and 3.95 ± 1.50, respectively. Salivary flow rates in SJS patients and NC were 0.02 ± 0.04 and 0.31 ± 0.20, respectively (p<0.001). While unstimulated salivary flow rates were correlated with ejection fraction (EF) of submandibular glands (r=0.423, p=0.025) in salivary gland scan, stimulated salivary flow rates were associated with EF of parotid glands (r=0.531, p=0.04). Salivary flow rates were inversely associated with ESSPRI scores (r=-0.390, p=0.036) and dryness domain of ESSPRI (r=-0.622 p<0.001) in SJS patients. Plasma and salivary sdc-1 levels were significantly higher in SJS patients than NC (both p<0.001), and inversely correlated with salivary flow rate (plasma, r=-0.515, p<0.001; saliva, r=-0.472, p=0.003). Plasma sdc-1 levels were positively correlated with salivary sdc-1 levels in SJS patients (r=0.632, p<0.001) but not in NC (r=0.217, p=NS). Plasma and salivary sdc-1 levels were related with submandibular gland dysfunction in salivary gland scan. While plasma sdc-1 levels showed an inverse correlation with EF (r=-0.426, p=0.038), salivary sdc-1 levels were inversely correlated with both uptake ratio at 20 minutes (r=-0.526, p=0.017) and EF (r=-0.446, p=0.019). Furthermore, salivary sdc-1 levels were correlated with serum levels of anti-Ro (r=0.397, p=0.030) and -La antibodies (r=0.441, p=0.015) and IgG, although serum level of IgG showed a marginal statistical significance (r=0.331, p=0.074).

Conclusion: Plasma and salivary sdc-1 levels are increased in SJS patients, which is associated with salivary gland dysfunction. In addition, salivary sdc-1 levels may be related with immune dysregulation in pathogenesis of SJS.

« Back to 2017 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/salivary-syndecan-1-levels-are-associated-with-salivary-gland-dysfunction-and-immune-dysregulation-in-patients-with-sjogrens-syndrome/