MicroRNAs (miRNAs)are a class of small non-coding RNA that regulate gene expression at the posttranscrip-tional level and play important roles in cell proliferation,differentiation,apoptosis and metabolism.Moreover,specific miR-NAs can be secreted or released from tissues and cells in different physiological or pathological statusand enteredinto blood circulation,and secreted miRNAs can be delivered into recipient cells and emerged as powerful regulatorsof a wide range of biological processes.Many recent studieshave shown that miRNAswere involved in the development and progression of type 2 diabetes (T2DM).Due to the widely source,highly stability,and specific expression patternunder different physiological or pathological conditions,circulating miRNAs may serve as a novelbiomarker for T2DM and may also participate in the devel-opment of type 2 diabetes.

Objective To develop a high performance liquid chromatographic method (HPLC) for the analysis of of cholesterol in erythrocyte membranes.Methods The study included 167 consecutive chest pain patients who underwent coronary artery angiography in the Department of Cardiology,Nanjing General Hospital of Nanjing Command between September 2012 and February 2013.According to the clinical symptoms and t angiographic results,patients were divided into three groups:acute coronary syndrome (ACS) group (n =46),stable angina pectoris (SAP) group (n =76) and the control group (n =45).After the erythrocyte sample was hypotonically lysed and washed,saponification was carried out in a polassium hydroxide solution at 70 ℃.After extraction by Hexane/isopropanol mixture,the sample was separated on a Lichrospher column and detected by ultraviolet absorbance at 208 nm.A mobile phase composed of acetonitrile-isopropyl alcohol was found to be the most suitable for this separation.Concentrations of cholesterol in erythrocyte membranes were tested.Analysis of variance with covariates (ANOVA) was used to evaluate differences in CEM levels among groups.The relationship between continuous variables was evaluated by Spearman's correlation coefficient.Results Under the chromatographic conditions described,retention time of the cholesterol was approximately 6.1 min.Good separation and detectability of cholesterol in erythrocyte membranes were obtained.The method proved to be linear in the injection range of cholesterol from 0.05 g to 2.00 g.Cholesterol content in erythrocyte membranes were (87.0 μg/mg,75.4-98.9 μg/mg),(92.9 μg/mg,83.8-109.0 μg/mg) and (173.9 μg/mg,140.0-188.8 μ g/mg) in the control,SAP and ACS groups,respectively.Cholesterol content in erythrocyte membranes was significantly higher in ACS group than that in SAP and control groups (P ＜ 0.01).Conclusion We have successfully developed a method for the determination of cholesterol in erythrocyte membranes with good sensitivity,specificity and repeatability.