The efficiency of serum lncRNA GAS5/miR-21 as biomarkers in patients with diabetes and diabetic nephropathy

Objective To elucidate the efficiency lncRNA GAS5 and miR-21 as biomarkers in diabetes mellitus and diabetic nephropathy. Methods The patients were divided into three groups, diabetic nephropathy group (DN group proven by renal biopsy, n=25, 14 males and 11 females), diabetes group (DM group, with normal urine albumin creatinine ratio, n=10, 4 males and 6 females), and normal control group (NC group, n=9, 4 males and 5 females). The expressions of lncRNA GAS5 and miR-21 in serum samples were detected by real-time quantitative PCR. The correlation between serum lncRNA GAS5 and miR-21 expressions and the clinical parameters was analyzed by T-test, Pearson, Spearman test and multivariate linear regression analysis. Differences of lncRNA GAS5 and miR-21 in different groups were analyzed by one-way analysis of variance. The ROC curve was used to analyze the diagnostic efficacy of lncRNA GAS5 and miR-21 in diabetes and diabetic nephropathy. All data were analyzed by SPSS 20.0 and GraphPad software, with P＜0.05 as considered statistically significant. Results (1) The expression of serum lncRNA GAS5 was significantly down-regulated and serum miR-21 was significantly up-regulated in both diabetes mellitus and diabetic nephropathy patients compared to the NC group all (P＜0.05). (2) In DN patients, the expression of serum lncRNA GAS5 was gradually up-regulated along with the increment of 24 h urinary protein. The expression of serum miR-21 was gradually up-regulated along with renal biopsy stage IIb-Ⅲ of DN (P＜0.05). (3) FBG and HbA1c were all negatively correlated with serum lncRNA GAS5 (P＜0.05), and FBG was independently correlated with serum lncRNA GAS5 (P＜0.05). Urine microalbumin, Total cholesterol(TC), Scr, Urea and SBP were all positively correlated with serum miR-21(P＜0.05). Albumin (ALB) and estimated GFR (eGFR) were negatively correlated with serum miR-21(P＜0.05), and ALB was independently correlated with serum miR-21 (P＜0.05). (4) The diagnostic efficiency of serum lncRNA GAS5, miR-21 and lncRNA GAS5/miR-21 as "diagnostic signature" for DM were was good (P＜0.05). (5) The diagnostic efficiency of serum miR-21 and lncRNA GAS5/miR-21 as "diagnostic signature" for DN were was good (P＜0.05). Conclusions (1) Serum lncRNA GAS5 had good diagnostic efficiency in diabetes mellitus. The sensitivity of lncRNA GAS5/miR-21 for diagnosis of diabetes was 85.71%, and specificity was 88.89%. (2) The level of serum miR-21 can be used as a noninvasive diagnostic marker for diabetic nephropathy.