miR-27a protects human mitral valve interstitial cell from TNF-alpha-induced inflammatory injury via up-regulation of NELL-1

MicroRNAs (miRNAs) have been reported to be associated with heart valve disease, which can be caused by inflammation. This study aimed to investigate the functional impacts of miR-27a on TNF-α-induced inflammatory injury in human mitral valve interstitial cells (hMVICs). hMVICs were subjected to 40 ng/mL TNF-α for 48 h, before which the expressions of miR-27a and NELL-1 in hMVICs were altered by stable transfection. Trypan blue staining, BrdU incorporation assay, flow cytometry detection, ELISA, and western blot assay were performed to detect cell proliferation, apoptosis, and the release of proinflammatory cytokines. We found that miR-27a was lowly expressed in response to TNF-α exposure in hMVICs. Overexpression of miR-27a rescued hMVICs from TNF-α-induced inflammatory injury, as cell viability and BrdU incorporation were increased, apoptotic cell rate was decreased, Bcl-2 was up-regulated, Bax and cleaved caspase-3/9 were down-regulated, and the release of IL-1β, IL-6, and MMP-9 were reduced. NELL-1 was positively regulated by miR-27a, and NELL-1 up-regulation exhibited protective functions during TNF-α-induced cell damage. Furthermore, miR-27a blocked JNK and Wnt/β-catenin signaling pathways, and the blockage was abolished when NELL-1 was silenced. This study demonstrated that miR-27a overexpression protected hMVICs from TNF-α-induced cell damage, which might be via up-regulation of NELL-1 and thus modulation of JNK and Wnt/β-catenin signaling pathways.

Pre-ejection mitral annular motion velocity responses to dobutamine infusion: a quantitative approach for assessment of myocardial viability

Dobutamine stress echocardiography [DSE] is widely used for detection of myocardial viability. The main limitation of DSE is its subjective interpretation. Assessment of mitral annular motion velocities with tissue Doppler imaging is a simple and quantitative measurement. To determine the relationship between myocardial viability and regional systolic mitral annular motion tissue Doppler velocities responses to dobutamine stress. Our study group included 42 patients with previous myocardial infarction referred for coronary angiography and revascularization. We did dobutamine stress tissue Doppler echocardiography [DSTDE] measuring velocities of pre-ejection wave [pre-Ej] and peak ejection wave [Ej] at rest and during low-dose dobutamine infusion. We did follow up echocardiography after 1 month. After exclusion of the normokinetic walls, we analyzed 196 walls. Using receiver operator characteristic ROC curves, the optimal cut-off value for viability assessment was an increase of 1.75cm/s in pre-ejection velocity during DSTDE [area under the curve 0.70, p<0.001]. On the other hand, the optimal cut-off value for viability assessment was an increase of 1.75cm/s in ejection velocity during DSTDE [area under the curve 0.613, p=0.01]. The sensitivity, specificity, and total accuracy of the DSTSE [pre-Ej] versus the gold standard for detection of myocardial viability were 66.15%, 67.94%, and 67.35%, respectively. The sensitivity, specificity, and total accuracy of the DTSE [Ej] were 56.92%, 64.12%, and 61.43%, respectively. There was a good correlation between the pre-Ej at 5 ug/kg/min dobutamine infusion and the pre-Ej after revascularization [r=0.64, p=0.01] while the correlation with the Ej was moderate [r=0.50, p=0.01]. Viable left ventricular myocardium could be identified easily and quantitatively with pre-ejection mitral annular velocity during dobutamine infusion. The pre-ejection wave during DSTDE showed greater sensitivity and specificity for the prediction of myocardial viability than the ejection wave