The levels of miR-93, miR-191, and miR-499 have been reported to be up-regulated in the tissues of experimental traumatic brain injury (TBI) rat models. However, the clinical diagnostic and prognostic values of the serum signatures of these 3 miRNAs in TBI remain unclear. The purpose of this study was to determine the expression levels of these 3 microRNAs (miRNAs) in the sera of TBI patients and to evaluate their relationships with the severity and clinical outcome of TBI. The serum levels of these miRNAs were assessed in TBI patients (n = 76) and healthy controls (n = 38) by quantitative reverse-transcription PCR. The severities and clinical outcomes of the TBI patients were evaluated with the Glasgow coma scale and the Glasgow outcome scale. The serum miR-93, miR-191, and miR-499 levels were significantly increased in the TBI patients compared with the controls at all examined time points, and these levels were significantly higher in the patients with severe TBI than in those with moderate or mild TBI (p < 0.05). The serum miR-93, miR-191, and miR-499 levels were significantly higher in the patients with a poor outcome than in those with a good outcome (p < 0.05). The AUCs of miR-93, miR-191, and miR-499 for distinguishing the TBI patients from the healthy controls were 1.000 (p < 0.001), 0.727 (p < 0.001) and 0.801 (p < 0.001), respectively. Interestingly, the AUCs of miR-93, miR-191, and miR-499 for distinguishing the mild TBI patients from the healthy controls were 1.000 (p < 0.001), 0.742 (p < 0.001) and 0.819 (p < 0.001), respectively. Taken together, these results indicate that miR-93, miR-191, and miR-499 are potentially valuable indicators of the diagnosis, severity, and prognosis of TBI.

Circulating microRNAs (miRNAs) are emerging biomarkers for type 2 diabetes mellitus (T2DM). However, a comprehensive characterization of the serum miRNA profile in patients with T2DM-associated microvascular disease (T2DMC) has rarely been reported. In this study, we obtained serum samples from 184 T2DM patients (92 with microvascular complications and 92 free of complications) and 92 age/gender-matched controls. The levels of 754 miRNAs were initially analyzed using a TaqMan Low Density Array (TLDA) in three pooled samples from 24 T2DM patients, 24 T2DMC patients and 24 controls. Markedly upregulated miRNAs in the patients’ groups were subsequently validated individually by quantitative reverse-transcription PCR (RT-qPCR) in the same samples used for TLDA and further confirmed in another larger cohort consisting of 68 patients with T2DM, 68 patients with T2DMC and 68 controls. Five miRNAs were significantly upregulated in T2DM patients (p < 0.05) including miR-661, miR-571, miR-770-5p, miR-892b and miR-1303. Moreover, the levels of the five miRNAs were higher in patients with complications than in those without complications. Regression analyses revealed the five miRNAs were significantly correlated with microvascular complications (p < 0.05). The five serum miRNAs identified in our study hold potential as auxiliary biomarkers and novel risk factors for T2DM-associated microvascular complications.

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