LncRNA MEG3 promotes neuronal apoptosis in rats with ischemic cerebral infarction via the TGF-ß1 pathway.

To study the influence of long non-coding ribonucleic acid maternally expressed gene 3 (lncRNA MEG3) on the neuronal apoptosis in rats with ischemic cerebral infarction, and to analyze its regulatory effect on the transforming growth factor-beta 1 (TGF-ß1) pathway. A total of 36 Sprague-Dawley rats were randomly assigned into sham group, model group and low expression group. Ischemic cerebral infarction modeling was constructed in rats of the model group and low expression group. Corresponding adenoviruses were intracranially injected in rats of low expression group to knock down lncRNA MEG3 expression. At 24 h after the operation, the neurological function of rats was evaluated in each group, and the expression level of lncRNA MEG3 in cerebral tissues was determined using quantitative polymerase chain reaction (qPCR). The infarct size was measured via 2,3,5-triphenyltetrazolium chloride (TTC) staining. The apoptosis level of neurons in cerebral tissues was determined using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. Besides, enzyme-linked immunosorbent assay (ELISA) was performed to determine the contents of inflammatory factors in cerebral tissues. Expression levels of apoptosis-associated proteins and vital genes in the TGF-ß1 signaling pathway in rat cerebral tissues were measured using Western blotting. Compared with the sham group, rats in the model group exhibited substantial increases in the neurological score and apoptosis level of neurons (p<0.01). Relative levels of lncRNA MEG3, interleukin (IL)-6, tumor necrosis factor-alpha (TNF-α), Caspase-3, TGF-ß1, small mothers against decapentaplegic homolog 2 (Smad2) and Smad3 (p<0.01) were higher in a model group than those in sham group. Notable declines in the content of IL-10 (p<0.01) and the ratio of B-cell lymphoma 2 (Bcl-2)/Bcl associated X protein (Bax) (p<0.01) were seen in the model group compared with the sham group. The abovementioned changes in the model group were partially abolished in the low expression group. LncRNA MEG3 is upregulated in the cerebral tissues of rats with ischemic cerebral infarction. It induces an inflammatory response, expands cerebral infarct size, and promotes neuronal apoptosis and impairment by activating the TGF-ß1 pathway.

Echocardiography underestimates stroke volume and aortic valve area: implications for patients with small-area low-gradient aortic stenosis.

BACKGROUND: Discordance between small aortic valve area (AVA; < 1.0 cm(2)) and low mean pressure gradient (MPG; < 40 mm Hg) affects a third of patients with moderate or severe aortic stenosis (AS). We hypothesized that this is largely due to inaccurate echocardiographic measurements of the left ventricular outflow tract area (LVOTarea) and stroke volume alongside inconsistencies in recommended thresholds. METHODS: One hundred thirty-three patients with mild to severe AS and 33 control individuals underwent comprehensive echocardiography and cardiovascular magnetic resonance imaging (MRI). Stroke volume and LVOTarea were calculated using echocardiography and MRI, and the effects on AVA estimation were assessed. The relationship between AVA and MPG measurements was then modelled with nonlinear regression and consistent thresholds for these parameters calculated. Finally the effect of these modified AVA measurements and novel thresholds on the number of patients with small-area low-gradient AS was investigated. RESULTS: Compared with MRI, echocardiography underestimated LVOTarea (n = 40; -0.7 cm(2); 95% confidence interval [CI], -2.6 to 1.3), stroke volumes (-6.5 mL/m(2); 95% CI, -28.9 to 16.0) and consequently, AVA (-0.23 cm(2); 95% CI, -1.01 to 0.59). Moreover, an AVA of 1.0 cm(2) corresponded to MPG of 24 mm Hg based on echocardiographic measurements and 37 mm Hg after correction with MRI-derived stroke volumes. Based on conventional measures, 56 patients had discordant small-area low-gradient AS. Using MRI-derived stroke volumes and the revised thresholds, a 48% reduction in discordance was observed (n = 29). CONCLUSIONS: Echocardiography underestimated LVOTarea, stroke volume, and therefore AVA, compared with MRI. The thresholds based on current guidelines were also inconsistent. In combination, these factors explain > 40% of patients with discordant small-area low-gradient AS.