The progressive loss of cardiomyocytes caused by cell death leads to cardiac dysfunction and heart failure (HF). Rapamycin has been shown to be cardioprotective in pressure-overloaded and ischemic heart diseases by regulating the mechanistic target of rapamycin (mTOR) signaling network. However, the impact of rapamycin on cardiomyocyte death in chronic HF remains undetermined. Therefore, in the current study we addressed this issue using a rat myocardial infarction (MI)-induced chronic HF model induced by ligating the coronary artery. Following surgery, rats were randomly divided into six groups, including the sham-, vehicle- and rapamycin-operated groups, at 8 or 12 weeks post-MI. A period of 4 weeks after MI induction, the rats were treated with rapamycin (1.4 mg-kg-day) or vehicle for 4 weeks. Cardiac function was determined using echocardiography, the rats were subsequently euthanized and myocardial tissues were harvested for histological and biochemical analyses. In the cell culture experiments with H9c2 rat cardiomyocytes, apoptosis was induced using angiotensin II (100 nM; 24 h). Cardiomyocyte apoptosis and autophagy were assessed via measuring apoptosis- and autophagy-associated proteins. The activities of mTOR complex 1 (mTORC1) and mTORC2 were evaluated using the phosphorylation states of ribosomal S6 protein and Akt, respectively. The activity of the endoplasmic reticulum (ER) stress pathway was determined using the levels of GRP78, caspase-12, phospho-JNK and DDIT3. Echocardiographic and histological measurements indicated that rapamycin treatment improved cardiac function and inhibited cardiac remodeling at 8 weeks post-MI. Additionally, rapamycin prevented cardiomyocyte apoptosis and promoted autophagy at 8 weeks post-MI. Rapamycin treatment for 4 weeks inhibited the mTOR and ER stress pathways. Furthermore, rapamycin prevented angiotensin II-induced H9c2 cell apoptosis and promoted autophagy by inhibiting the mTORC1 and ER stress pathways. These results demonstrated that rapamycin reduced cardiomyocyte apoptosis and promoted cardiomyocyte autophagy, by regulating the crosstalk between the mTOR and ER stress pathways in chronic HF.

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Circulating microRNAs (miRNAs) have been proposed as potential biomarkers for left ventricular remodeling in postinfarction heart failure (HF). However, the diagnostic reproducibility of the use of circulating miRNAs may be affected by the temporal expression of miRNAs following myocardial infarction (MI). In the current study, using a MI-induced HF rat cohort (4-, 8-, and 12-week post-MI groups), we investigated the temporal expression of plasma miRNAs during the development of left ventricular remodeling. The plasma miRNA expression profile was obtained using miRNA sequencing. The expression of candidate miRNAs in plasma and tissues was examined with real-time PCR. Target genes of candidate miRNAs were predicted using a parallel miRNA-messenger RNA expression profiling approach. The value of plasma miRNAs as biomarkers for left ventricular remodeling was evaluated in patients with postinfarction HF (n = 32) and control patients with stable angina and without significant coronary lesions and HF (n = 16) with real-time PCR. Although the expression levels of miR-20a-5p, miR-340-5p, and let-7i-5p were temporally regulated in plasma, myocardium, and peripheral blood mononuclear cells, the expression levels of plasma miRNAs, especially miR-20a-5p, were associated with the development of left ventricular remodeling in the postinfarction HF rat cohort. The target genes of these 3 miRNAs were associated with the mechanistic target of rapamycin, nuclear factor-κB, tumour necrosis factor, apoptosis, and p53 signaling pathways. Additionally, the plasma levels of miR-20a-5p, miR-340-5p, and let-7i-5p were significantly increased in patients with postinfarction HF. However, only the expression levels of miR-20a-5p presented significant positive correlations with left ventricular internal end diastolic dimension and left ventricular end diastolic volume. In conclusion, the expression levels of plasma miR-20a-5p were significantly associated with the degree of left ventricular dilatation, and plasma miR-20a-5p may be a potential biomarker for postinfarction left ventricular remodeling.

Optimization of intratracheal instillation is necessary to establish an ideal animal model of acute lung injury (ALI) in order to further reveal the cellular and molecular pathogenesis of ALI. It is possible that instilling air from a prefilled syringe may promote the delivery of reagents into the alveolar spaces, resulting in different pulmonary responses. In the present study, the influence of instilling air by trans-tracheal intratracheal instillation in a lipopolysaccharide (LPS)-induced mouse model of ALI was investigated. The bronchoalveolar lavage (BAL) fluid biochemical index, BAL fluid differential cell counts, lung wet/dry weight ratio, lung histology and BAL fluid interleukin-8 (IL-8) levels were assessed 24 h subsequent to intratracheal instillation. Instilled air promoted LPS-induced ALI, as indicated by the severity of acute pulmonary inflammation and increased IL-8 release. In conclusion, this study indicates that instilled air may be used to improve the intratracheal instillation procedure and to establish a more reliable animal model of ALI.

Rationale:Anti-thrombosis therapy for atrial fibrillation (AF) management and stroke prevention is an important aspect of disease management. Novel oral anticoagulants (NOACs) are recommended by guidelines for AF management. However, if one can switch one NOAC to another when the former showed a poor effect has not been fully determined.Patient concerns:A 52-year-old man was admitted to our center for heart failure and AF with a thrombus in the left atrium.Diagnoses:Cardiomyopathy was diagnosed by cardiac magnetic resonance (CMR) and echocardiography.Interventions:He was prescribed rivaroxaban (20 mg daily) as treatment, and dabigatran (150 mg twice daily) was used when the thrombus was found to be non-response to rivaroxaban.Outcomes:The rivaroxaban did not diminish the atrial thrombus, and dabigatran was given instead which finally eliminated the thrombus.Lessons:Individualized responsiveness to NOACs should be considered and paid more attention to during clinical practice.

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Background Myocardial dysfunction caused by sepsis (SIMD) leads to high mortality in critically ill patients. We investigated the function and mechanism of long non-coding RNA MAPKAPK5-AS1 (lncRNA MAPKAPK-AS1) on lipopolysaccharide (LPS)-induced inflammation response in vivo and in vitro. Method Male SD rats were utilized for in vivo experiments. Rat cardiomyocytes (H9C2) were employed for in vitro experiments. Western blotting was employed to measure protein expression, and RT-PCR was performed to measure mRNA expression of inflammation factors. TUNEL and flow cytometry were carried out to evulate cell apoptosis. Result The results showed that the expression of MAPKAPK5-AS1 was increased, while the expression of miR-124-3p was decreased in the inflammatory damage induced by LPS in vivo and in vitro. Knockdown of MAPKAPK5-AS1 reduced LPS-induced cell apoptosis and inflammation response, while overexpression of miR-124-3p weakened the effects of MAPKAPK5-AS1 knockdown on LPS-induced cell apoptosis and inflammation response. Moreover, miR-124-3p was identified as a downstream miRNA of MAPKAPK5-AS1, and E2F3 was a target of miR-214-3p. MAPKAPK5-AS1 knockdown increased the expression of miR-124-3p, while miR-124-3p overexpression reduced the expression of MAPKAPK5-AS1. In addition, miR-124-3p was found to downregulate E2F3 expression in H9C2 cells. Conclusion MAPKAPK5-AS1/miR-124-3p/E2F3 axis regulates LPS-related H9C2 cell apoptosis and inflammatory response.