Geniposide Prevents Hypoxia/Reoxygenation-Induced Apoptosis in H9c2 Cells: Improvement of Mitochondrial Dysfunction and Activation of GLP-1R and the PI3K/AKT Signaling Pathway.

BACKGROUND/AIMS: Myocardial ischemia/reperfusion injury is a major cause of morbidity and mortality associated with coronary heart disease. Many studies have demonstrated that natural products are promising chemotherapeutic drugs counteracting the loss of cardiomyocytes. Thus, the purpose of the present study was to investigate the effects of geniposide, a traditional Chinese herb extract from Gardenia jasminoides J. Ellis, on cardiomyocyte apoptosis induced by hypoxia/reoxygenation (H/R) in H9c2 cells, and their underlying mechanisms. METHODS: Cell viability and apoptosis ratio were assessed using the cell counting kit-8 assay and Annexin V/propidium iodide (PI) staining. The concentrations of lactate dehydrogenase (LDH), intracellular total superoxide dismutase (T-SOD), and malondialdehyde (MDA) were detected by microplate reader. The production of reactive oxygen species/reactive nitrogen species (ROS/RNS), the level of mitochondrial calcium, and mitochondrial membrane potential depolarization were measured by confocal laser scanning microscopy. Mitochondrial morphology was visualized using transmission electron microscopy. The expressions of Bcl-2 mRNA and Caspase-3 mRNA were measured by reverse transcription-polymerase chain reaction (RT-PCR). The protein levels of cleaved caspase-3, Bcl-2, Bax, AKT, p-AKTserine473, cytochrome-c were detected by western bloting. RESULTS: Geniposide pretreatment increased cell viability, decreased LDH levels in the supernatant, and inhibited cardiomyocyte apoptosis caused by H/R. Furthermore, geniposide reversed mitochondrial dysfunction by decreasing oxidative stress products (ROS/RNS and MDA), increasing anti-oxidative enzyme (T-SOD) level, improving mitochondrial morphology, attenuating mitochondrial calcium overload and blunting depolarization of mitochondrial membrane. Moreover, geniposide pretreatment increased Bcl-2 level and decreased Bax level, thus enhancing the Bcl-2/Bax ratio. Consistent with the above result, Bcl-2 mRNA expression was upregulated and caspase-3 mRNA expression was downregulated by geniposide. In addition, geniposide decreased the protein expression of cleaved caspase-3 and cytochrome-c and increased the level p-AKTserine473. The protective effects of geniposide were partially reversed by glucagon-like pepitide-1 receptor antagonist exendin-(9-39) and the phosphatidylinositol 3 kinase (PI3K) inhibitor LY294002. CONCLUSIONS: Our results suggest that geniposide pretreatment inhibits H/R-induced myocardial apoptosis by reversing mitochondrial dysfunction, an effect in part due to activation of GLP-1R and PI3K/AKT signaling pathway.

TNAP inhibition attenuates cardiac fibrosis induced by myocardial infarction through deactivating TGF-ß1/Smads and activating P53 signaling pathways.

Tissue nonspecific alkaline phosphatase (TNAP) is expressed widely in different tissues, modulating functions of metabolism and inflammation. However, the effect of TNAP on cardiac fibrosis remains controversial and needs to be further studied. The present study aims to investigate the role of TNAP on myocardial infarction (MI)-induced fibrosis and its mechanism. TNAP was upregulated in patients with MI, both in serum and injured hearts, and predicted in-hospital mortality. TNAP was also significantly upregulated after MI in rats, mostly in the border zone of the infarcted hearts combined with collagen synthesis. Administration of TNAP inhibitor, tetramisole, markedly improved cardiac function and fibrosis after MI. In the primary cultures of neonatal rat cardiac fibroblasts (CFs), TNAP inhibition significantly attenuated migration, differentiation, and expression of collagen-related genes. The TGF-ß1/Smads signaling suppression, and p-AMPK and p53 upregulation were involved in the process. When p53 inhibitor was administered, the antifibrotic effect of TNAP inhibition can be blocked. This study provides a direct evidence that inhibition of TNAP might be a novel regulator in cardiac fibrosis and exert an antifibrotic effect mainly through AMPK-TGF-ß1/Smads and p53 signals.

Comparative evaluation of copeptin and NT-proBNP in patients with severe acute decompensated heart failure, and prediction of adverse events in a 90-day follow-up period: A prospective clinical observation trial.

The present study compared the prognostic value of a marker, the C-terminal section of the arginine vasopressin prohormone (copeptin), with N-terminal B-type natriuretic peptide (NT-proBNP) in patients with severe acute decompensated heart failure. A prospective, observational cohort study was conducted in a tertiary care hospital and enrolled 129 patients with severe acute decompensated heart failure. Clinicians were blinded to investigational markers except NT-proBNP, and the study participants were followed up for 90 days. The end-point was a composite of cardiovascular death or re-hospitalization due to decompensated heart failure. Of the 129 patients enrolled, 47 reached the end-point and 82 were in a stable condition during follow-up. Receiver operating characteristic curve analysis revealed that the areas under curve for the prediction of adverse events within 90 days were similar for copeptin [0.602±0.052; 95% confidence interval (CI), 0.499-0.705], NT-proBNP (0.659±0.048; 95% CI, 0.565-0.753) and their combination (0.670±0.050; 95% CI, 0.573-0.767). Kaplan-Meier survival analysis showed that the predictive value of NT-proBNP regarding the probability of survival was superior compared with that of copeptin (log-rank test for trend, P=0.001 vs. 0.040). Furthermore, multivariate Cox proportional-hazards regression analysis revealed that increased NT-proBNP and copeptin plasma concentrations were significant independent predictors of adverse events. The present study provided evidence that copeptin has similar predictive properties compared with NT-proBNP regarding adverse events within 90-days in patients with severe acute decompensated heart failure, but that copeptin may not provide superior 90-day prediction compared to NT-proBNP.