Reperfusing the myocardium - a damocles Sword

SOCS6 Promotes Mitochondrial Fission and Cardiomyocyte Apoptosis and Is Negatively Regulated by Quaking-Mediated miR-19b

Background. Mitochondrial dysfunction and abnormal mitochondrial fission have been implicated in the complications associated with I/R injury as cardiomyocytes are abundant in mitochondria. SOCS6 is known to participate in mitochondrial fragmentation, but its exact involvement and the pathways associated are uncertain. Methods and Results. The expression of SOCS6 was analyzed by western blot in cardiomyocytes under a hypoxia and reoxygenation (H/R) model. A dual-luciferase reporter assay was used to confirm the direct interaction between miR-19b and the 3 ${}^{\prime }$ -UTR of Socs6. In the present study, we found that Socs6 inhibition by RNA interference attenuated H/R-induced mitochondrial fission and apoptosis in cardiomyocytes. A luciferase assay indicated that Socs6 is a direct target of miR-19b. The overexpression of miR-19b decreased mitochondrial fission and apoptosis in vitro. Moreover, the presence of miR-19b reduced the level of SOCS6 and the injury caused by I/R in vivo. There were less apoptotic cells in the myocardium of mice injected with miR-19b. In addition, we found that the RNA-binding protein, Quaking (QK), participates in the regulation of miR-19b expression. Conclusions. Our results indicate that the inhibition of mitochondrial fission through downregulating Socs6 via the QK/miR-19b/Socs6 pathway attenuated the damage sustained by I/R. The QK/miR-19b/Socs6 axis plays a vital role in regulation of mitochondrial fission and cardiomyocyte apoptosis and could form the basis of future research in the development of therapies for the management of cardiac diseases.

Comparative Analysis of Infarct Size Limiting Activity of δ-Opioid Receptor Agonists in Reperfused Heart In Vivo

The study examined the effects of δ-opioid receptor (OR) agonists on infarct size on cardiac ischemia (45 min) and reperfusion (120 min) in vivo model in rats narcotized with α-chloralose. The OR agonists were injected intravenously 5 min prior to reperfusion, OR antagonists were administered 10 min before reperfusion. A selective δ-OR agonist BW373U86 (1 mg/kg) reduced the infarct size/area at risk ratio. A selective δ₁-OR agonist DPDPE injected in the doses of 0.1 or 0.969 mg/kg produced no effect on infarct size. The selective δ₂-OR agonist deltorphin II (0.12 mg/kg) reduced infarct size/area at risk ratio by 2 times. The δ-OR agonist p-Cl-Phe-DPDPE (1 mg/kg) reduced infarct size/area at risk ratio by 40%. Naltrexone and naloxone methiodide, the peripheral OR antagonists, and selective δ₂-OR antagonist naltriben prevented the infarct size limiting effect of deltorphin II. Therefore, activation of peripheral δ₂-OR enhanced cardiac resistance against toxic action of reperfusion. During reperfusion, deltorphin II demonstrated the most pronounced cardioprotective activity.

Cardioprotective role of phyllanthin against myocardial ischemia-reperfusion injury by alleviating oxidative stress and inflammation with increased adenosine triphosphate levels in the mice model

BACKGROUND

Ischemic heart disease is an imperative cause of high morbidity and mortality globally. The cardiac ischemia/reperfusion damage occur in both reperfusion and ischemia.

OBJECTIVE

In this exploration, we have planned to examine the cardio-protective action of phyllanthin against the myocardial ischemic-reperfusion injury in mice.

MATERIALS AND METHODS

The myocardial ischemic reperfusion injury (MI-RI) stimulated via coronary artery occlusion, followed by the 10 mg/kg of phyllanthin treatment. The serum cardiac markers and pro-inflammatory markers level was investigated by using the assay kits. The expressions of oxidative stress and inflammatory markers level were investigated by immunohistochemical analysis. Lipid peroxidation, antioxidant enzymes, and ATPase levels level was examined by standard methods. The expression of oxidative stress markers were inspected by the reverse transcription polymerase chain reaction technique. The heart histology was investigated microscopically.

RESULTS

The phyllanthin treatment increased the body weight, and heart weight also diminished the infarct size in the MI/RI mice. Cardiac markers status was diminished and the blood pressure markers were augmented by the phyllanthin. Histological analysis revealed the protective role of phyllanthin. Suppressed lipid peroxidation and enhanced antioxidant enzymes were noted in the phyllanthin treated mice MI-RI mice. Phyllanthin appreciably suppressed the pro-inflammatory regulators that is, NF-αB p65, IL-6, IL-1β, and TNF-α and enhanced the antioxidant marker expressions. ATPase levels were improved by the phyllanthin in the MI-RI mice.

CONCLUSION

These novel findings were confirmed the therapeutic role of phyllanthin against the MI-RI in mice. Hence, it can be a promising agent to treat the MI-RI induced cardiac dysfunction.

Butorphanol protects PC12 cells against OGD/R-induced inflammation and apoptosis

The aim of the present study was to examine the effects of butorphanol on neural injury in an oxygen glucose deprivation/reoxygenation (OGD/R) model using PC12 cells, and to investigate whether mitochondrial apoptosis was involved in these effects. To establish the OGD/R model, PC12 cells were cultured under hypoxia and low glucose conditions. Expression levels of inflammatory cytokines were evaluated by detecting the levels of tumor necrosis factor-α, interleukin (IL)-1β, IL-6 and monocyte chemoattractant protein-1. Oxidative stress was evaluated by measuring the levels of reactive oxygen species, lactate dehydrogenase activity and myeloperoxidase concentration. Apoptosis, protein expression and cell viability were determined by flow cytometry, western blotting and by using a Cell Counting Kit-8, respectively. Compared with the control group, cell viability, expression of inflammatory factors and oxidative stress were all decreased in the OGD/R group. All the above changes could be mitigated by treatment with butorphanol. In addition, butorphanol treatment resulted in a significant upregulation of Bax, and downregulation of Bcl-2, activated caspase-3, caspase-9 and poly ADP-ribose polymerase, increased the expression of X-linked inhibitor of apoptosis protein and enhanced ATP activity. To conclude, these results suggested that the protective effects of butorphanol are associated with the inhibition of OGD/R-induced inflammation and apoptosis injury, and may be partially associated with the inhibition of mitochondrial apoptosis.

The combination of neutrophil-to-lymphocyte ratio and platelet correlation parameters in predicting the no-reflow phenomenon after primary percutaneous coronary intervention in patients with ST-segment elevation myocardial infarction

OBJECTIVE

To evaluate the predictive value of the neutrophil-to-lymphocyte ratio (NLR), mean platelet volume (MPV), and platelet distribution width (PDW) for the no-reflow phenomenon in patients with ST-segment elevation myocardial infarction. Methods: Patients who underwent primary percutaneous coronary intervention from January 2017 to April 2019 were consecutively enrolled in this study and were split into the control and no-reflow groups. Logistic regression analysis was used to determine the independent predictors. Receiver operating characteristic curves were carried out to evaluate the predictive value. Results: A total of 455 patients were included and the incidence of the no-reflow was 19.6%. After the adjustment of confounding factors, logistic regression analyses showed that the NLR (odds ratio [OR] per unit increase: 1.107, 95% confidence interval [CI]: 1.044-1.172, p = .001), MPV (OR: 1.398, 95% CI: 1.010-1.937, p = .044), and PDW (OR: 1.392, 95% CI: 1.012-1.914, p = .042) were all independent predictors. In the prediction of the no-reflow, the NLR had the largest area under the curve of 0.650 (95% CI: 0.593-0.708) with 90% sensitivity and 36% specificity. The area under the curve of the combination of NLR + MPV was 0.676 and that of NLR + PDW was 0.654. Conclusions: The NLR, MPV and PDW are all associated with the no-reflow. However, there is no significant difference in the predictive value of these indicators. The combinations of NLR and platelet-associated parameters also do not show a better predictive value than NLR alone.