Background: Aberrant angiogenesis plays a role in the pathogenesis of Sjögren's syndrome (SS).
Objectives: The aim of this study was to compare the levels of vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) in stimulatory parotid saliva and in serum in healthy subjects (HS), patients with primary SS (pSS) and secondary SS (sSS) and to evaluate the expression of EGF, proangiogenic VEGF165 and antiangiogenic VEGF165 b mRNA isoforms. Additionally, we determined the salivary levels of serine/arginine splicing factor (SRSF1), which regulates VEGF165 and VEGF165 b expression.
Material and methods: The study comprised 34 women (16 with pSS and 18 with sSS) and healthy subjects for blood and saliva sampling. EGF and VEGF levels in saliva and serum and salivary SRSF1 levels were determined by enzyme-linked immunosorbent assay (ELISA). The expression of VEGF165 , VEGF165 b and EGF in peripheral blood mononuclear cells (PBMC) was evaluated by quantitative polymerase chain reaction (qPCR).
Results: There were no differences in the levels of EGF, VEGF, SRSF1 and in the expression of the EGF, VEGF165 and VEGF165 b between HS and SS patients, or between pSS and sSS patients. The salivary levels of VEGF165 and EGF were significantly higher in pSS, sSS and HS than serum levels. Levels of SRSF1 correlated positively with VEGF and EGF levels. Levels of EGF, VEGF and SRSF1 correlated with each other.
Conclusions: The balance of VEGF isoforms is not disturbed in SS. Saliva is more sensitive for the detection of EGF and VEGF than serum, but salivary levels of those proteins are not representative for SS.
Keywords: Sjögren’s syndrome; angiogenesis; epidermal growth factor; vascular endothelial growth factor.