Evaluation of lipid oxidative stress status in Sjögren syndrome patients

PURPOSE. We evaluated the levels of lipid oxidative stress markers and inflammatory cells from tears and conjunctiva of patients with Sjögren syndrome (SS) and normal subjects. METHODS. We examined 31 eyes of 16 patients (16 females) with SS and 15 eyes of 10 healthy controls (2 males and 8 females) in this prospective study. All subjects underwent a Schirmer test, measurement of tear film break-up time, vital stainings, confocal microscopy of the conjunctiva, tear collection for hexanoyl-lysine (HEL), ELISA, and conjunctival brush cytology. Brush cytology samples underwent immunohistochemistry (IHC) staining with HEL and 4-hydroxy-2- nonenal (4HNE). Hematoxylin-eosin and IHC staining with HEL and 4HNE also were performed on conjunctival samples of SS patients and controls. RESULTS. The tear stability and vital staining scores were significantly worse in eyes of SS patients compared to the controls. Conjunctival inflammatory cell density was significantly higher in SS subjects compared to controls. The numbers of conjunctival cells stained positively for HEL and 4HNE were significantly higher in SS patients compared to controls. Tear HEL concentrations correlated significantly with staining scores and inflammatory cell density in confocal microscopy. Conjunctival specimens also revealed higher numbers of cells stained positively for inflammatory markers, as well as HEL and 4HNE in the IHC stainings. CONCLUSIONS. Increase of the oxidative stress status in the conjunctiva of SS patients appears to have a role in the pathogenesis of dry eye disease. A close relationship may exist between reactive oxygen species (ROS) production, lipid peroxidation related membrane damage, and inflammatory processes in dry eye.