Both castration and goserelin acetate ameliorate myocardial ischemia reperfusion injury and apoptosis in male rats

Asiaticoside alleviates cardiomyocyte apoptosis and oxidative stress in myocardial ischemia/reperfusion injury via activating the PI3K-AKT-GSK3β pathway in vivo and in vitro

Background

Myocardial ischemia/reperfusion (MI/R) is one of the most important links in myocardial injury, causing damage to cardiac tissues including cell apoptosis, oxidative stress, and other serious consequences. Asiaticoside (AS), a new compound synthesized from genistein, is cardioprotective. This paper presents new evidence for the protective role of AS against MI/R injury in vitro and in vivo.

Methods

First, BALB/c mice underwent surgical ligation of the left anterior descending (LAD) artery to establish an MI/R animal model, and HL-1 cells were subjected to oxygen-glucose deprivation/reperfusion (OGD/R) to establish an in vitro model. Myocardial infarct size was examined by triphenyl tetrazolium chloride (TTC) staining, histopathological changes detected in heart tissues were observed using hematoxylin and eosin (H&E) and Masson staining, heart tissue apoptosis was assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Enzyme-linked immunosorbent assay (ELISA) kits were used to analyze cardiac troponin I (CTnI), creatine kinase-muscle and brain (CK-MB), lactate dehydrogenase (LDH), superoxide dismutase (SOD), malondialdehyde (MDA), and reduced glutathione (GSH). Cell viability was evaluated using Cell Counting Kit-8 (CCK-8) and live/dead assay. Cell apoptosis, reactive oxygen species (ROS), mitochondrial membrane potential, and mitochondrial superoxide were detected by flow cytometry and fluorescence microscopy. Both the protein expression in myocardial tissues and cardiomyocytes were examined by western blot.

Results

In the in vivo MI/R experiments,pretreatment of AS reduced myocardial infarct size, decrease leakage of myocardial enzyme, suppressed myocardial apoptosis, myocardial collagen deposition, and oxidative stress. In the in vitro OGD/R experiments, HL-1 cells pretreated with AS had increased cell viability, decreased apoptosis rates and depolarization of mitochondrial membrane potential, and attenuated intracellular ROS and mitochondrial superoxide. Moreover, AS downregulated the expression of apoptotic protein, and promoted phosphorylation of PI3K, AKT, and GSK3β, which was reversed by PI3K inhibitor LY294002.

Conclusions

The AS compound protects against MI/R injury by attenuating oxidative stress and apoptosis via activating the PI3K/AKT/GSK3β pathway in vivo and vitro.

Cilostazol protects against myocardial ischemia and reperfusion injury by activating transcription factor EB (TFEB)

Although cilostazol was proved to have antitumor biological effects, its function in myocardial ischemia and reperfusion (I/R) injury and the underlying mechanisms were not fully illustrated yet. In this study, a rat model of I/R injury was constructed and quantitative real-time PCR, Western blot, and immunofluorescence (IF) assay were performed. Our results showed that cilostazol increased LC3 II/LC3 I ratio, reduced p62 abundance, and promoted the expressions of LAMP1, LAMP2, cathepsin B, and cathepsin D, indicating that cilostazol could activate autophagy and elevated lysosome activation. Following analysis showed that cilostazol enhanced nuclear protein expression of transcription factor EB (TFEB), an important regulator of autophagy-lysosome pathway. Furthermore, CCI-779, an inhibitor of TFEB, could reverse the effects of cilostazol on autophagic activity and lysosome activation. Importantly, cilostazol suppressed I/R injury-induced apoptosis by decreasing the cleavage of caspase 3 and PARP. Enzyme-linked immunosorbent assay showed that cilostazol reduced the serum levels of CTn1 and CK-MB and decreased infract size caused by I/R injuries. Altogether this study suggested that cilostazol protects against I/R injury by regulating autophagy, lysosome, and apoptosis in a rat model of I/R injury. The protective mechanism of cilostazol was partially through increasing the transcriptional activity of TFEB.

MicroRNA-144 attenuates cardiac ischemia/reperfusion injury by targeting FOXO1

Cardiovascular ischemic disease refers to a large class of conditions that are harmful to human health. A number of previous studies have demonstrated that microRNAs (miRs) have notable roles in regulating cardiac injury. miR-144 is influential in the differentiation, growth, and metastatic processes of cells; however, the impact of miR-144 in cardiac ischemia/reperfusion (I/R) injury has not been thoroughly elucidated to date. In the present study, reverse transcription quantitative polymerase chain reaction was used to evaluate RNA expression. In addition, TTC staining was performed to detect the infarct area of the ischemic myocardia and a terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling assay was utilized to detect the apoptosis of the myocardia. It was observed that miR-144 expression is downregulated in an I/R model in rats and that overexpression of miR-144 significantly reduced myocardial ischemic injury and apoptosis. Consistent with this result, similar findings were demonstrated in H9c2 cells subjected to hypoxia/reoxygenation. Bioinformatic analysis using MiRanda and TargetScan, and luciferase assays confirmed that forkhead box protein O1was the target of miR-144. These findings suggest that miR-144 may be exploited as a novel molecular marker or therapeutic target for myocardial I/R injury.

shRNA interference of NLRP3 inflammasome alleviate ischemia reperfusion-induced myocardial damage through autophagy activation

Myocardial ischemia-reperfusion (I/R) injury always occur during the recovery of myocardial blood supply with high morbidity and mortality. Although, various therapeutic schedules were applied in clinic, there are real problems that have to be resolved on curative effect. Nod-like receptor protein 3 (NLRP3) inflammasome has moderation effects on cellular damage and inflammatory reaction after I/R injury. Our research aims to investigate a more effective approach to restrain the activation of NLRP3 inflammasome in treating myocardial I/R injury. Results indicated that cell viability, Bax/Bcl-2 expression were affected hardly by sh-NLRP3 transfection in normal cells. However, the decreased cell viability and increased Bax/Bcl-2 expression level caused by I/R were remarkably suppressed through sh-NLRP3 transfection. Besides that, the reduced levels of pro-autophagy proteins (Beclin1, Agt7, LC3II/LC3I) while enhanced level of anti-autophagy protein (p62) and apoptosis-related proteins (Bax/Bcl-2) were significantly repressed via sh-NLRP3 transfection. Nevertheless, the autophagy inhibitor 3 MA could reverse the results. Moreover, in vivo experiment suggested that NLRP3 was up-regulated in wild type (WT) rats with I/R injury. The expansion of infarct size induced by ischemia was tremendously constricted in NLRP3 knockout (KO) rats. NLRP3 silence had nearly no impact on myocardial enzymes (AST, LDH and CK) expressions, inflammatory factors (TNF-α and IL-1β) expressions and cell apoptosis in rats without I/R injury. Nonetheless, the elevated levels of myocardial enzymes, inflammatory factors and cell apoptosis caused by I/R injury were vastly inhibited in NLRP3 KO rats. Furthermore, NLRP3 KO itself would lead to higher level of pro-autophagy proteins (Beclin1, Agt7, LC3II/LC3I) while lower level of anti-autophagy protein (p62) in vivo. The decreased expressions of pro-autophagy proteins while increased expressions of anti-autophagy protein induced by I/R injury were remarkably suppressed by NLRP3 KO. Taken together, our study indicated that shRNA interference of NLRP3 inflammasome attenuated myocardial I/R injury via autophagy activation. These findings demonstrated that NLRP3 KO may a promising therapy in myocardial I/R injury.

Role of E-selectin for diagnosis of myocardial injury in children of age up to 14 years

BACKGROUND

Effects of myocardial injury on E-selectin remain unclear. Thus, we investigated the diagnostic value of E-selectin for myocardial injury in children of no more than 14 years of age, which determined the scoring method of myocardial injury.

METHODS

In this prospective study, plasma E-selectin, cardiac troponin I (cTnI) and creatine kinase isoenzyme MB (CK-MB) concentrations in pediatric patients with myocardial injury (myocardial injury group, n=85) were measured. The control group comprised 80 patients without myocardial injury, and the case-control study method was selected at the same time. The definition of cardiac injury was based on cTnI and CK-MB (with or possibly without abnormal ECG evidence). Diagnostic value of E-selectin for myocardial injury was determined by analyzing receiver operating characteristic (ROC) curves.

RESULTS

The differences between the two groups were of statistical significance (P<0.001). For the 85 patients with myocardial injury, the area under the ROC curve (AUC) value for plasma E-selectin levels was 0.945 with a 95% CI of 0.899-0.991 and the optimal diagnostic cut-off value 29.67 ng/ml (positive likelihood ratio (positive LR=72.5); AUC value for plasma cTnI level was 0.848 with a 95% CI: 0.737-0.960 and the optimal diagnostic cut-off value was 0.155 µg/L (positive LR=12.3); AUC value for plasma CK-MB levels was 0.946 with a 95% CI: 0.903-0.989 and the optimal diagnostic cut-off value 24.26 IU/L (positive LR=72.5).

CONCLUSIONS

E-selectin is more effective than cTnI in diagnosing myocardial injury as an important biological marker of myocardial injury- an important index of pediatric cardiac injury score.

Curcumin inhibits autophagy and apoptosis in hypoxia/reoxygenation-induced myocytes

Primary percutaneous coronary intervention, or thombolytic therapy, provides effective myocardial blood reconstruction in patients with acute myocardial infarction to reduce acute myocardial ischemic injury. However, reperfusion can itself induce cardiomyocyte death, termed myocardial reperfusion injury (I/R). Hypoxia/reoxygenation (H/R) induces apoptosis and excessive autophagy among cardiomyocytes, leading to cell death. The present study investigated the effect of curcumin, a natural extract from Curcuma longa, on these two cellular processes in H9c2 myocytes. The levels of cellular apoptosis and autophagy were found to be upregulated in the H9c2 myocytes during H/R and were correlated with a reduced rate of cell survival. However, curcumin significantly suppressed the levels of H/R‑induced apoptosis (expression of annexin V) and autophagy (LC3B‑II/LC3B‑I ratio) in the H9c2 myocytes and promoted cell survival. Additionally, the expression of B‑cell lymphoma 2 (Bcl‑2) was significantly downregulated and the expression levels of Bcl‑2‑associated X protein, beclin‑1, Bcl‑2/adenovirus E1B 19 kDa interacting protein 3 (BNIP3) and silent information regulation 1 (SIRT1) were significantly upregulated in myocytes following H/R injury. These effects on the expression of these proteins were reversed by curcumin treatment. These findings suggested that the protective effect of curcumin against H/R injury in the H9c2 myocytes was through the inhibition of apoptosis and autophagy by inducing the expression of Bcl‑2 and inhibiting the expression levels of Bax, beclin‑1, BNIP3 and SIRT1. Therefore, curcumin may offer a promising therapeutic approach for the treatment of cardiomyocyte injury resulting from I/R.