Association between low levels of serum miR-638 and atherosclerotic plaque vulnerability in patients with high-grade carotid stenosis.

OBJECTIVE: Carotid artery atherosclerosis is a major cause of ischemic stroke. However, reliable criteria to identify patients with high-risk carotid plaques beyond the severity of stenosis are still lacking. Circulating microRNAs (miRNAs) are being postulated as biomarkers for a variety of vascular immune-inflammatory diseases. The authors investigated whether cell-free circulating miR-638, highly expressed in vascular smooth muscle cells and implicated in proliferative vascular diseases, is associated with vulnerable atherosclerotic plaques in high-risk patients with advanced carotid artery stenosis undergoing carotid endarterectomy (CEA). METHODS: The authors conducted a prospective study in 22 consecutive symptomatic patients with high-grade carotid stenosis undergoing CEA and 36 age- and sex-matched patients without ischemic stroke history or carotid atherosclerosis (control group). In addition, they reviewed data from a historical group of 9 CEA patients who underwent long-term follow-up after revascularization. Total RNA was isolated from all serum samples, and relative miR-638 expression levels were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and compared among groups. A correlation analysis of serum miR-638 levels with vascular risk factors and treatments, and with plaque features, was performed. The ability of serum miR-638 to discriminate between the non-CEA control group and the different CEA groups was assessed by receiver operating characteristic evaluation. A logistic regression model was employed to examine the association between stratified CEA patients and serum miR-638 levels. RESULTS: Serum levels of miR-638 were significantly lower in symptomatic CEA patients (p = 0.009) and particularly in the subgroup of CEA patients who had experienced stroke (p = 0.0006) than in non-CEA controls. Discrimination of high-risk plaques was accurate (area under the curve [AUC] 0.66 for symptomatic CEA patients in general and 0.76 for those who had experienced stroke). When only patients with high cardiovascular risk were considered, the diagnostic value of serum miR-638 from symptomatic CEA patients and CEA patients who had experienced stroke improved (AUC 0.79 and 0.85). Moreover, serum miR-638 was negatively correlated with the occurrence of stroke, smoker status, presence of bilateral pathology, coronary artery disease, and cholesterol treatment; and with the high-risk fibroatheroma plaques extracted from CEA patients. Multivariate logistic regression analysis demonstrated that serum miR-638 was an independent predictor of plaque instability. Furthermore, serum miR-638 appeared to attain good discrimination for atherosclerotic stenosis in CEA patients based on analysis of blood samples obtained in the historical group before and 5 years after intervention (p = 0.04) (AUC = 0.79). CONCLUSIONS: According to this preliminary proof-of-concept study, serum miR-638 might constitute a promising noninvasive biomarker associated with plaque vulnerability and ischemic stroke, particularly in individuals with elevated cardiovascular risk.

Usefulness of circulating microRNAs for the prediction of early preeclampsia at first-trimester of pregnancy.

To assess the usefulness of circulating microRNAs (miRNAs) as non-invasive molecular biomarkers for early prediction of preeclampsia, a differential miRNA profiling analysis was performed in first-trimester pooled sera from 31 early preeclampsia patients, requiring delivery before 34 weeks of gestation, and 44 uncomplicated pregnancies using microfluidic arrays. Among a total of 754 miRNAs analyzed, the presence of 63 miRNAs (8%) was consistently documented in the sera from preeclampsia and control samples. Nevertheless, only 15 amplified miRNAs (2%) seemed to be differentially, although modestly, represented (fold change range: 0.4-1.4). After stem loop RT-qPCR from individual samples, the statistical analysis confirmed that none of the most consistent and differentially represented miRNAs (3 overrepresented and 4 underrepresented) were differentially abundant in serum from preeclamptic pregnancies compared with serum from normal pregnancies. Therefore, maternal serum miRNA assessment at first-trimester of pregnancy does not appear to have any predictive value for early preeclampsia.

Characterization of mesenchymal stem cells isolated from the rabbit fetal liver.

Physiological attributes of mesenchymal stem cells (MSCs) including straightforward manipulation, multilineage differentiation, immunoregulation, and tropism for injury settings render them ideal therapeutic agents for tissue repair/regeneration. Nevertheless, further studies in suitable animal models of disease are needed to translate the potential of MSCs into clinical applications. We report here the isolation and preliminary characterization of MSCs from fetal rabbit liver (fl-MSCs). Compared with MSCs isolated from adult rabbit bone marrow, fl-MSCs had superior growth rate, clonogenic capability, and plastic adherence owing to their developmental immaturity. Both cytochemical staining and mRNA expression analysis of fl-MSCs confirmed mesodermal lineage differentiation into adipocytes, osteocytes, and chondrocytes. Moreover, fl-MSCs were capable to prevent lymphocyte proliferation both in a 2-way MLC and upon phytohemagglutinin (PHA) stimulation. In contrast, fl-MSCs co-cultured with allogeneic lymphocytes induced proliferation of the latter. Relatedly, although freshly isolated fl-MSCs did express neither major histocompatibility complex (MHC) class I/II nor CD80/CD86, all these immune synapse components were induced upon in vitro culture. Furthermore, fl-MSCs became efficiently transduced for long-term transgene expression with a retroviral vector. Thus, the special biological qualities of fl-MSCs endow them as model candidate vehicles/agents for gene/cell therapy strategies applied to a variety of rabbit models of injury, such as osteochondral lesions.