Serum MicroRNA-137 Serves as a Novel Biomarker for Cerebral Atherosclerosis Diagnosis and Cerebrovascular Event Prediction

Atherosclerosis (AS) is one of the main potential factors of cardiovascular disease (a disease with the highest mortality).1 It seriously endangers human health, especially the health and intellectual activities of middle- and old-aged people. It is noted that cerebral AS may cause acute cerebral circulatory disorders and chronic cerebral ischemic symptoms, such as transient ischemic attack (TIA) and stroke. It has been known that the main cellular components of blood vessels are endothelial cells (ECs) and vascular smooth muscle cells (VSMCs).2 Thus, cerebral AS, which has complex etiology and pathogenesis, is believed to be closely related to the inflammatory response caused by vascular endothelial injury and the dysfunction of vascular ECs and VSMCs.3 In addition, the higher total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels are significantly related to the occurrence of cerebral AS.4 The hypersensitivity C-response protein (hs-CRP) is a vital inflammatory factor related to the formation of AS.5 Small noncoding microRNAs (miRNAs) are single-stranded RNA molecules with a length of approximately 21–23 nucleotides. Generally speaking, miRNAs can induce mRNA degradation or inhibit mRNA translation.6 It is well known that miRNAs are related to many important biological processes, including proliferation, invasion, and apoptosis.7–9 MiRNAs seem to be potential biomarkers for various diseases, such as prostate cancer,10 glioblastoma,11 and liver cirrhosis.12 In addition, miRNAs have been known to be associated with arteriosclerosis.13 Moreover, miR-126-5p,14 miR-126, and miR-14315 have been shown to function as biomarkers for AS. A study on gene and miRNA profiling of human induced pluripotent stem cell–derived ECs showed that miR-137 was increased in human embryonic stem cell–derived ECs and human induced pluripotent stem cell–derived ECs during endothelial differentiation.16 More importantly, studies have found that miR-137 can regulate the function of vascular ECs and VSMCs, and promote angiogenesis,17,18 suggesting a vital role of miR-137 in vascular biology. The dysfunction of vascular ECs and VSMCs has been well known to be a key mechanism of the cerebral AS; consequently, miR-137 may be related to the pathogenesis of cerebral AS and stroke. Currently, the diagnosis of cerebral AS, however, is made by neuroimaging techniques, with the absence of circulating biomarkers. Therefore, studies regarding the clinical significance of circulating miRNA expression in patients with cerebral AS are helpful for the early intervention of high-risk patients, and then decrease the occurrence of cerebrovascular adverse events. Thus, this study aimed to assess whether miR-137 could be used as a biomarker for cerebral AS diagnosis and prediction of cerebrovascular events.