microRNA-18a is a genetic marker for the early diagnosis of cerebral injury induced by type 2 diabetes.

The present study aimed to investigate the value of microRNA (miRNA)-18a for the early diagnosis of cerebral injury in patients with type 2 diabetes. Blood samples were collected from patients with type 2 diabetes, admitted to hospital between January and December 2013. The patients were randomly divided into three groups, which included one control and two experimental groups of severely and mildly diabetic patients (33 individuals per group). The levels of biochemical indicators in the serum, including S100 protein, neuron-specific enolase, myelin basic protein and endothelin-1, were determined. The mRNA and protein expression levels of hypoxia-inducible factor (HIF)-1α in the serum were measured by quantitative polymerase chain reaction (qPCR) and western blot analysis, respectively. In addition, the serum expression levels of miRNA-18a were determined by qPCR. The concentrations of the biochemical indicators in the severe diabetes group were significantly higher compared with those from the other two groups. Furthermore, the mRNA and protein expression levels of HIF-1α in the severe diabetes group were significantly upregulated compared with the other groups. However, the levels of miRNA-18a in the severe diabetes group were significantly downregulated compared with the other groups. The present study demonstrated that the elevation of biochemical indicators in the serum and the upregulation of HIF-1α mRNA and protein expression are associated with the downregulation of miRNA-18a. Therefore, miRNA-18a may be a potential genetic marker for the early diagnosis of cerebral injury induced by type 2 diabetes.