Empagliflozin alleviates myocardial I/R injury and cardiomyocyte apoptosis via inhibiting ER stress-induced autophagy and the PERK/ATF4/Beclin1 pathway.

To explore the mechanisms underlying the specific inhibitor targeting SGLT-2 empagliflozin in alleviating myocardial ischaemia-reperfusion (I/R) injury. A mouse model of I/R injury and H2O2-induced H9C2 cell model were established. The expressions of Bcl-2, Bax, LC3, Beclin1, GRP78, CHOP, PERK, ATF4, ATF6, IREα and P62 were examined by western blot, immunofluorescence or immunohistochemistry staining, respectively. The cardiac function was measured by echocardiography, TCC staining, lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) activity. Cell apoptosis was analysed by TUNEL, Annexin V/propidium iodide (PI) staining and caspase 3 and 9 activities. CCK-8 assay was used for analysing cell viability. PBA, TUDC and 3-MA were utilised for blocking ER stress and autophagy, respectively. Empagliflozin suppressed myocardial I/R injury in vivo and H2O2-induced cardiomyocyte apoptosis in vitro. Blockade of ER stress and autophagy inhibited H2O2-induced cardiomyocyte apoptosis. ER stress activated autophagy through the PERK signalling in H2O2-treated H9C2 cells. Empagliflozin suppressed ER stress-induced autophagy by inhibiting the PERK/ATF4/Beclin1 signalling. H2O2 and I/R-induced cardiomyocyte apoptosis was restrained by empagliflozin through inhibition of ER stress-induced autophagy. Empagliflozin suppressed ER stress-induced autophagy via suppressing the PERK/ATF4/Beclin1 signalling, thus alleviating myocardial I/R injury and cardiomyocyte apoptosis.

[Role of homocysteine in the pathogenesis of alcoholic cardiomyopathy].

OBJECTIVE: To explore the role of homocysteine in the pathogenesis of alcoholic cardiomyopathy. METHODS: A total of 69 male Wistar rats were randomly assigned into two groups: alcohol-fed group and the control. Cardiac function was assessed by pulse Doppler. Plasma Hcy levels were examined using automatic biochemical instrument (chemiluminescence). The protein expression of MMP-9 was evaluated using immunohistochemical method, and collagen fiber of myocardium was quantitative analyzed by Masson stain. RESULTS: After heavy drinking, the LVEDd of alcohol-fed group were larger than the control group [(7.0±0.6) mm vs (5.0±0.4) mm, P<0.05], the LVEF and FS were lower in the 4th month (52%±8% vs 78%±4%, 31%±3% vs 47%±2%, P<0.05), the data changed more significantly (P<0.01) in the 6th month. The level of plasma Hcy from alcohol-fed group was significantly higher from the 2nd month than that before the experiment [(18.1±3.1) µmol/L vs (9.8±2.1) µmol/L, P<0.01], and it was higher in 4th month than that in 2nd month [(26.3±4.0) µmol/L vs (18.1±3.1) µmol/L, P<0.05], it was highest in 6 months. After 4-month and 6-month drinking, the expression of MMP-9 protein from alcohol group was higher than before the experiment (0.161%±0.019%, 0.263%±0.014% vs 0.050%±0.008%, P<0.01). Masson staining showed myocardial collagen of alcohol group was more after 4-month and 6-month drinking than those before the experiment (10.23%±1.20% vs 0.50%±0.09%; 22.41%±2.57% vs 0.50%±0.09%, P<0.01). Plasma Hcy and cardiac tissue MMP-9 is a significant positive correlation (r=0.848, P<0.01). CONCLUSION: Long-term and large drink liquor can lead to plasma Hcy levels significantly increased, and participate cardiac remodeling and the pathogenesis of ACM through increasing the expression of myocardial tissue MMP-9 protein.