Soluble LRIG2 is a potential biomarker for type 2 diabetes mellitus

Background: Early diagnosis and treatment of type 2 diabetes can delay the onset of microvascular and macrovascular complications. Therefore, the identification of a novel biomarker for diagnosing diabetes is necessary. In the present study, the role of serum soluble leucine-rich repeats and immunoglobulin like domains 2 (sLRIG2) was investigated as a diagnostic biomarker of type 2 diabetes. Methods: A total of 240 subjects with newly diagnosed type 2 diabetes (n=80), prediabetes (n=80), or normal glucose tolerance (NGT; n= 80) were included in this study. The fasting serum sLRIG2 level was measured using a quantitative sandwich enzyme immunoassay technique with an enzyme-linked immunosorbent assay (ELISA). Serum sLRIG2 levels were compared among the three groups, and the associations of serum sLRIG2 levels with clinical variables were investigated. Results: Serum sLRIG2 levels were significantly higher in subjects with type 2 diabetes (16.7 +/- 8.0 ng/mL) than in subjects without diabetes (NGT group: 12.3 +/- 5.3 ng/mL, P<0.001; prediabetes group: 13.2 +/- 5.8 ng/mL, P=0.002). Glycosylated hemoglobin (HbA1c: r=0.378, P<0.001) and blood glucose (fasting: r=0.421, P<0.001; 2-hour postprandial: r=0.433, P<0.001) correlated more strongly with sLRIG2 than any other clinical variables. Conclusions: The serum sLRIG2 levels correlated with glucose parameters; thus, sLRIG2 might be a novel diagnostic biomarker for type 2 diabetes.