Relationship of serum S100A8/A9 complex and retinal inflammation in patients with diabetic retinopathy

Abstract

Background Inflammation is one of the most popular aspects in the studies of diabetic retinopathy (DR) mechanisms.Researches showed that S100A8/A9 participate in the inflammatory procedure of many diseases, however, the relationship between S100A8/A9 complex and retinal inflammation of DR needs to be researched. Objective This study was to detect the serum S100A8/A9 level of diabetes mellitus (DM) and DR patients, and explore its role in DM an DR development. Methods A cases-controlled study was carried out.The DR patients, type 2 DM patients without retinal change and heathy controls were enrolled in Shanghai Xuhui Central Hospital from January to June 2014, and 30 patients for each group.The DR patients were subgrouped to non-proliferative DR (NPDR) group and proliferative DR (PDR) group.The periphery blood was collected to isolate the serum, and serum S100A8/A9 complex level was detected by ELISA.Serum high-sensitivity C-reactive protein (hsCRP) and glycosylated hemoglobin A1C (HbAlc) level was assayed by immunity turbidimetry and immune agglutination respectively. Results Serum S100A8/A9 complex levels in the DR group, DM group and normal control group were (9.74±0.59), (11.41±0.64) and (6.46±0.62)μg/L, respectively, and the serum S100A8/A9 complex level in the DM group and DR group was significantly higher than that in the normal control group, and the serum S100A8/A9 complex level in the DM group raised in compared with the DR group (all at P<0.01). Serum hsCRP levels in the DR group, DM group and normal control group were (1.40±0.34), (1.27±0.13) and (1.11±0.12)mg/L, respectively, with the highest value in the DR group and the lowest value in the normal control group ( all at P=0.00). The serum HbAlc levels were higher in the DR group and DM group than those in the normal control group (both at P=0.00), while no significant difference was found in the serum HbAlc level between DR group and DM group (P=0.12). There was no significant differece in the serum S100A8/A9, hsCRP and HbAlc levels between NPDR group and PDR group (t=-0.10, P=0.92; t=-0.17, P=0.87; t=0.66, P=0.51). A weak positive correlation was seen between serum S100A8/A9 level and serum hsCRP level (r=0.36, P=0.00). Conclusions As an inflammatory marker, S100A8/A9 complex might play an important role in the pathogenesis and development of DR.Intensive control of glycemia can alleviate retinal inflammation in DM patients. Key words: Diabetes mellitus/complications; Diabetic retinopathy; Inflammation; S100A8/A9 complex