Myocardial ischemia is a disease with high morbidity and mortality, for which reperfusion is currently the standard intervention. However, the reperfusion may lead to further myocardial damage, known as myocardial ischemia/reperfusion injury (MI/RI). Oxidative stress is one of the most important pathological mechanisms in reperfusion injury, which causes apoptosis, autophagy, inflammation, and some other damage in cardiomyocytes through multiple pathways, thus causing irreversible cardiomyocyte damage and cardiac dysfunction. This article reviews the pathological mechanisms of oxidative stress involved in reperfusion injury and the interventions for different pathways and targets, so as to form systematic treatments for oxidative stress‐induced myocardial reperfusion injury and make up for the lack of monotherapy.

Background/Aims: Qiliqiangxin (QL), a traditional Chinese medicine, has been demonstrated to be effective and safe for the treatment of chronic heart failure. Left ventricular (LV) remodeling causes depressed cardiac performance and is an independent determinant of morbidity and mortality after myocardial infarction (MI). Our previous studies have shown that QL exhibits cardiac protective effects against heart failure after MI. The objective of this study was to explore the effects of QL on myocardial fibrosis in rats with MI and to investigate the underlying mechanism of these effects. Methods: A rat model of acute myocardial infarction was induced by ligating the left anterior descending coronary artery. The rats were treated with QL (1.0 g/kg/day) for 4 weeks after surgery. Echocardiography and histology examination were performed to evaluate heart function and fibrosis, respectively. Protein levels of transforming growth factor-β1 (TGF-β1), phosphorylated Smad3 (p-Smad3), phosphorylated Smad7 (p-Smad7), collagen I (Col- I), alpha smooth muscle actin (a-SMA), tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), nuclear factor κB (NF-κB), and phosphorylated inhibitor of kappa B alpha (p-IκBα) were measured by western blot analysis. Results: QL treatment ameliorated adverse cardiac remodeling 8 weeks after AMI, including better preservation of cardiac function, decreased inflammation, and reduced fibrosis. In addition, QL treatment reduced Col-I, a-SMA, TGF-β1, and p-Smad3 expression levels but increased p-Smad7 levels in postmyocardial infarct rat hearts. QL administration also reduced the elevated levels of cardiac inflammation mediators, such as TNF-α and IL-6, as well as NF-κB and p-IκBα expression. Conclusions: QL therapy exerted protective effects against cardiac remodeling potentially by inhibiting TGF-β1/Smad3 and NF-κB signaling pathways, thereby preserving cardiac function, as well as reducing myocardial inflammation and fibrosis.

Metabolic modulation is a promising therapy for ischemic heart disease and heart failure. This study aimed to clarify the regional modulatory effect of Qiliqiangxin capsules (QLQX), a traditional Chinese medicine, on cardiac metabolic phenotypes. Sprague–Dawley rats underwent left anterior descending coronary artery ligation and were treated with QLQX and enalapril. Striking global left ventricular dysfunction and left ventricular remodeling were significantly improved by QLQX. In addition to the posterior wall, QLQX also had a unique beneficial effect on the anterior wall subject to a severe oxygen deficit. Cardiac tissues in the border and remote areas were separated for detection. QLQX enhanced the cardiac ¹⁸F-fluorodeoxyglucose uptake and the levels and translocation of glucose transport 4 (GLUT4) in the border area. Meanwhile, it also suppressed glucose transport 1 (GLUT1) in both areas, indicating that QLQX encouraged border myocytes to use more glucose in a GLUT4-dependent manner. It was inferred that QLQX promoted a shift from glucose oxidation to anaerobic glycolysis in the border area by the augmentation of phosphorylated pyruvate dehydrogenase, pyruvate dehydrogenase kinases 4, and lactic dehydrogenase A. QLQX also upregulated the protein expression of fatty acid translocase and carnitine palmitoyl transferase-1 in the remote area to possibly normalize fatty acid (FA) uptake and oxidation similar to that in healthy hearts. QLQX protected global viable cardiomyocytes and promoted metabolic flexibility by modulating metabolic proteins regionally, indicating its potential for driving the border myocardium into an anaerobic glycolytic pathway against hypoxia injuries and urging the remote myocardium to oxidize FA to maximize energy production.

Background/Aims:This study aimed to compare the clinical value of the peak time point and area under the curve (AUC) of miRNAs and conventional biomarkers in acute myocardial infarction (AMI).Methods:A literature search was carried out in PubMed, Web of Science, Embase, and Cochrane systematically. Screening studies, extracting data, and assessing article quality were performed independently by two researchers. Also, the names of miRNAs in the included studies were standardized by the miRBase database.Results:A total of 40 studies, encompassing 6,960 participants, were included in this systematic review. The samples of circulating miRNAs were mainly from the plasma. The results of this systematic review displayed that miR-1-3p, miR-19b-3p, miR-22-5p, miR-122-5p, miR-124-3p, miR-133a/b, miR-134-5p, miR-150-5p, miR-186-5p, miR-208a, miR-223-3p, miR-483-5p, and miR-499a-5p reached peak time earlier and showed a shorter time window than the conventional biomarkers despite the different collection times of initial blood samples. miR-1-3p, miR-19b-3p, miR-133a/b, miR-208a/b, miR-223-3p, miR-483-5p, and miR-499a-5p were shown to be more valuable than classical biomarkers for the early diagnosis of AMI, and these miRNAs appeared to have the most potential biomarkers within 4 h of the onset of symptoms except miR-133a/b and miR-208b. Moreover, combined miRNAs or miRNAs combined with classical biomarkers could compensate for the deficiency of single miRNA and conventional biomarker in sensitivity or specificity for an optimal clinical value.Conclusions:miR-1-3p, miR-19b-3p, miR-208a, miR-223-3p, miR-483-5p, and miR-499a-5p are promising biomarkers for AMI due to their satisfactory diagnostic accuracy and short time window (within 4 h of the onset of symptoms).

Patients with heart failure (HF) are more susceptible to cognitive impairment, but the mechanism is still unclear. This study aimed to observe the dynamic changes in brain glucose metabolism and neuronal structure in different stages of HF. An HF rat model was established by ligating the anterior descending branch of the left coronary artery. To simulate acute heart failure (AHF) and chronic heart failure (CHF) in the clinic, relevant laboratory indexes were detected 10 and 60 days after ligation. The results showed that the model rats had systolic HF. Cognitive function was not obviously impaired in 10-day rats with HF, while the memory and learning functions were significantly impaired in 60-day rats with HF. The brain glucose metabolism in 10-day rats compensatorily increased in the prefrontal cortex (PFC), medial PFC (mPFC), cingulate gyrus, and basal ganglia (BG). In contrast, the metabolism of 60-day rats reduced in the PFC and BG. Meanwhile, the neuronal structure slightly changed in 10-day rats with HF, but neuronal karyopyknosis, reduced Nissl bodies, and swollen organelles were found in 60-day rats with HF. In conclusion, brain glucose metabolism and neuronal structure showed a dynamic evolution. Rats with AHF were in a compensatory state for increased glucose metabolism and slight neuronal damage. As a result, no significant cognitive impairment was observed. However, rats with CHF had significantly decreased cerebral glucose metabolism and neuronal degeneration, contributing to the cognitive function after HF.