Diabetes Mellitus Reveals Its Micro-Signature

See related article, pages 810–817With 285 millions individuals affected worldwide in 2010 and more than 400 millions expected in 2030, diabetes mellitus is a major public health concern and a huge economic burden. This disease, characterized by chronic elevation of blood glucose levels, is frequently associated with micro- and macrovascular complications, putting diabetic patients at risk for heart and renal failure, stroke, lower limb amputations, and blindness.1 In view of the dramatic impact of diabetes on public health, the definition of new methods predicting the manifestation of the disease and the occurrence of its debilitating complications deserves the highest priority. In this issue of Circulation Research , Zampetaki et al report that a group of circulating RNA molecules belonging to the microRNA family is considerably less abundant in the blood of diabetes patients compared to normoglycemic individuals.2 Interestingly, a reduction in the level of these microRNAs is already detectable years before the appearance of the disease and is correlated with subclinical and manifest peripheral artery disease. These findings suggest that plasma microRNA levels may become valuable tools to assess the probability of diabetes manifestation in high-risk individuals displaying impaired fasting glucose and could assist in predicting the occurrence of micro- and macrovascular complications in diabetic patients.MicroRNAs are small noncoding RNA molecules discovered in 1993 in Caenorhabditis elegans. Later on, they were identified in many other eukaryotes and it became clear that all mammalian cells contain hundreds of them.3 Many microRNAs are ubiquitously expressed, but some of them are restricted to a limited number of tissues where they play specific roles. Since their discovery, microRNAs have been the focus of intense investigations and have rapidly turned out to form a complementary RNA–directed regulatory network acting in concert with transcription factors to tune gene expression. In …