Genetic Lineage Tracing of Pericardial Cavity Macrophages in the Injured Heart.

BACKGROUND: Macrophages play an important role in cardiac repair after myocardial infarction (MI). In addition to the resident macrophages and blood-derived monocytes, Gata6+ cavity macrophages located in the pericardial space were recently reported to relocate to the injured myocardium and prevent cardiac fibrosis. However, there is no direct genetic evidence to support it. METHODS: We used dual recombinases (Cre and Dre) to specifically label Gata6+ pericardial macrophages (GPCMs) in vivo. For functional study, we generated genetic systems to specifically ablate GPCMs by induced expression of DTR (diphtheria toxin receptor) or knockout of Gata6 (GATA binding protein 6) gene in GPCMs. We used these genetic systems to study GPCMs in pericardium intact MI model. RESULTS: Dual recombinases-mediated genetic system targeted GPCMs specifically and efficiently. Lineage tracing study revealed accumulation of GPCMs on the surface of MI heart without deep penetration into the myocardium. We did not detect significant change of cardiac fibrosis or function of MI hearts after cell ablation or Gata6 knockout in GPCMs. CONCLUSIONS: GPCMs minimally invade the injured heart after MI. Nor do they prevent cardiac fibrosis and exhibit reparative function on injured heart. This study also underlines the importance of using specific genetic tool for studying in vivo cell fates and functions.

Alteration of the gut microbiota and metabolite phenylacetylglutamine in patients with severe chronic heart failure.

Chronic Heart Failure (CHF) is the end result of nearly all cardiovascular disease and is the leading cause of deaths worldwide. Studies have demonstrated that intestinal flora has a close relationship with the development of Cardiovascular Disease (CVD) and plays a vital role in the disease evolution process. Phenylacetylglutamine (PAGln) a metabolite of the intestinal flora, is one of the common chronic kidney disease toxins. Its concentrations in plasma were higher in patients with major adverse cardiovascular events (MACE) however, its variation in patients with various degrees of CHF has rarely been reported. Therefore, we collected stool and plasma samples from 22 healthy controls, 29 patients with NYHA Class III and 29 patients with NYHA Class IV CHF (NYHA stands for New York Heart Association) from the Department of Cardiology of Shanghai Fengxian District Central Hospital. Next, we analyzed these samples by performing bacterial 16S ribosomal RNA gene sequencing and liquid chromatography tandem mass spectrometry. The result shows: The Chao 1 index was significantly lower in both NYHA class III and NYHA class IV than it was in the control group. The beta diversity was substantially dissimilar across the three groups. The linear discriminant analysis effect size analysis (LEfSe) showed that the bacterial species with the largest differences were Lachnospiraceae in control group, Enterobacteriaceae in NYHA class III, and Escherichia in NYHA class IV. The concentration of PAGln was significantly different between CHF and control groups and increased with the severity of heart failure. Finally, the correlation analysis represented that Parabacteroides and Bacteroides were negatively correlated to brain natriuretic peptide (BNP) and PAGln; Romboutsia and Blautia adversely associated with PAGln; Klebsiella was positively interrelated with BNP; Escherichia-Shigella was positively correlated with PAGln and BNP; Alistipes was contrasted with BNP; and Parabacteroides was negatively correlated with the left ventricular end-diastolic diameter (LVEDD). This study presented that the intestinal flora and its metabolite PAGln were altered with different grades of CHF and illustrated the effects of the gut flora and its metabolite on CHF.

Effects of Intracoronary Pro-urokinase or Tirofiban on Coronary Flow During Primary Percutaneous Coronary Intervention for Acute Myocardial Infarction: A Multi-Center, Placebo-Controlled, Single-Blind, Randomized Clinical Trial.

Background: To determine whether intracoronary pro-urokinase or tirofiban improves myocardial reperfusion during primary percutaneous coronary intervention (PCI) for acute ST-segment elevation myocardial infarction (STEMI). Methods: The study included patients with acute STEMI presenting within 12 h of symptoms at 11 hospitals in China between November 2015 and July 2017. Patients were randomized to receive selective intracoronary infusion of recombinant pro-urokinase (20 mg), tirofiban (10 µg/kg), or saline (20 mL) proximal to the infarct-related lesion over a 3-min period before stent implantation during primary PCI. The primary outcome was final corrected thrombolysis in myocardial infarction (TIMI) frame count (CTFC) after PCI. Results: This study included 345 patients. Initial angiography identified a high-grade thrombus (TIMI 4-5) in 80% of patients. Final CTFC after PCI was significantly lower in the pro-urokinase (P < 0.001) and tirofiban (P < 0.001) groups than in the saline group and similar between the pro-urokinase and tirofiban groups (P > 0.05). The pro-urokinase (P = 0.008) and tirofiban groups (P = 0.022) had more complete ST-segment resolution at 2 h and lower peak creatine kinase-MB levels after PCI than the saline group (P = 0.006 and P = 0.023). The 30-day incidence of major adverse cardiac events was 4.5% in the pro-urokinase group, 3.4% in the tirofiban group, and 2.6% in the saline group. The incidence of in-hospital TIMI major bleeding events was low and comparable between groups. Conclusions: Adjunctive intracoronary pro-urokinase or tirofiban given before stent implantation during primary PCI improves myocardial reperfusion without increasing the incidence of major bleeding events.

Homocysteine level and gestational diabetes mellitus: a systematic review and meta-analysis.

AIMS: It is reported that elevated homocysteine (Hcy) level represents an independent risk factor for gestational diabetes mellitus (GDM). However, the relationship between Hcy level and GDM remains controversial. Our study aimed to systematically review available literature linking Hcy to GDM for a comprehensive understanding of the relationship between circulating Hcy level and GDM in humans. METHODS: PubMed, The Cochrane Library, and Web of Science were searched for studies published up to January 2021. Manual searches of references of the relevant studies were also conducted. Standard mean difference (SMD) with 95% confidence interval (95%CI) were calculated to evaluate the relationship between Hcy level and GDM using the Review Manager 5.3 and Stata 12.0. RESULTS: Of 106 references reviewed, 12 studies with a total of 712 GDM patients contributed to the present meta-analysis. Hcy level was significantly elevated in women with GDM compared with those without GDM (SMD = 0.55; 95% CI: 0.25-0.85, p = .0003). In the subgroup meta-analyses, this evidence was more consistent among women with Hcy sampling during the second trimester (SMD = 0.76, 95% CI: 0.34-1.18, p = .0004) and with average age ≥30 years (SMD = 0.69, 95% CI: 0.25-1.12, p = .002). CONCLUSION: The evidence indicated that the level of circulating Hcy was significantly elevated among women with GDM compared with those with normal glucose tolerance, especially with mean age ≥30 years and in the second trimester.

MicroRNA-146a-3p/HDAC1/KLF5/IKBα signal axis modulates plaque formation of atherosclerosis mice.

BACKGROUND: Atherosclerosis (AS) is a multifocal, smoldering immune inflammatory disease of medium and large arteries driven by lipids. The aim of this study is to discuss the mechanism of microRNA-146a-3p (miR-146a-3p)/histone deacetylase 1 (HDAC1)/Krüppel-like factor 5 (KLF5)/inhibitors of kappa B α (IKBα) signal axis in plaque formation of AS mice. METHODS: ApoE-/- mice were fed with high-fat feed for 12 weeks to establish AS mice model. The expression of miR-146a-3p, KLF5, HDAC1 and IKBα in aortic wall tissues of AS mice was tested. The targeting relationship between miR-146a-3p and HDAC1 was verified. AS mice were injected with miR-146a-3p antagomir or HDAC1 overexpression to verify the impacts of miR-146a-3p and HDAC1 on blood lipids and inflammatory factors in serum, aortic wall apoptotic cells, antioxidant stress capacity and the plaque area in AS mice. VECs proliferation and apoptosis were also measured in vitro. RESULTS: miR-146a-3p and KLF5 were increased while HDAC1 and IKBα were reduced in aortic wall tissues of AS mice. miR-146a-3p directly targeted to HDAC1. Depletion of miR-146a-3p or restoration of HDAC1 was correlated to lower plasma lipid level, reduced inflammatory factors in serum, attenuated aortic wall apoptosis, increased antioxidant stress capacity and improved the stability of pathological plaque of AS mice. miR-146a-3p down-regulation or HDAC1 up-regulation promoted VECs proliferation and inhibited apoptosis. CONCLUSION: Functional studies show that depleted miR-146a-3p advances HDAC1 and IKBα expression as well as inhibits KLF5 expression to facilitate the stability of pathological plaques in AS mice.

Distinct Phenotypes Induced by Different Degrees of Transverse Aortic Constriction in C57BL/6N Mice.

The transverse aortic constriction (TAC) model surgery is a widely used disease model to study pressure overload-induced cardiac hypertrophy and heart failure in mice. The severity of adverse cardiac remodeling of the TAC model is largely dependent on the degree of constriction around the aorta, and the phenotypes of TAC are also different in different mouse strains. Few studies focus on directly comparing phenotypes of the TAC model with different degrees of constriction around the aorta, and no study compares the difference in C57BL/6N mice. In the present study, C57BL/6N mice aged 10 weeks were subjected to sham, 25G TAC, 26G TAC, and 27G TAC surgery for 4 weeks. We then analyzed the different phenotypes induced by 25G TAC, 26G TAC, and 27G TAC in c57BL/6N mice in terms of pressure gradient, cardiac hypertrophy, cardiac function, heart failure situation, survival condition, and cardiac fibrosis. All C57BL/6N mice subjected to TAC surgery developed significantly hypertrophy. Mice subjected to 27G TAC had severe cardiac dysfunction, severe cardiac fibrosis, and exhibited characteristics of heart failure at 4 weeks post-TAC. Compared with 27G TAC mice, 26G TAC mice showed a much milder response in cardiac dysfunction and cardiac fibrosis compared to 27G TAC, and a very small fraction of the 26G TAC group exhibited characteristics of heart failure. There was no obvious cardiac dysfunction, cardiac fibrosis, and characteristics of heart failure observed in 25G TAC mice. Based on our results, we conclude that the 25G TAC, 26G TAC, and 27G TAC induced distinct phenotypes in C57BL/6N mice.

Visfatin level and gestational diabetes mellitus: a systematic review and meta-analysis.

It is reported that elevated visfatin level is associated with gestational diabetes mellitus (GDM). However, the relationship between visfatin level and GDM remains controversial. The aim of our study was to systematically review available literature linking visfatin to GDM for a comprehensive understanding of the relationship between circulating visfatin level and GDM in human. PubMed, The Cochrane Library and Web of Science were searched for studies published up to July 2020. Standard mean difference with 95% confidence interval was calculated to evaluate the relationship between visfatin level and GDM using the Review Manager 5.3 and Stata 12.0. The evidence indicated that no significant difference was observed in the level of circulating visfatin between the women with GDM and normal glucose tolerance, suggesting circulating visfatin level is not independently related to GDM. Nevertheless, visfatin is involved in the development of GDM in obese women.

Generation of a self-cleaved inducible Cre recombinase for efficient temporal genetic manipulation.

Site-specific recombinase-mediated genetic technology, such as inducible Cre-loxP recombination (CreER), is widely used for in vivo genetic manipulation with temporal control. The Cre-loxP technology improves our understanding on the in vivo function of specific genes in organ development, tissue regeneration, and disease progression. However, inducible CreER often remains inefficient in gene deletion. In order to improve the efficiency of gene manipulation, we generated a self-cleaved inducible CreER (sCreER) that switches inducible CreER into a constitutively active Cre by itself. We generated endocardial driver Npr3-sCreER and fibroblast driver Col1a2-sCreER, and compared them with conventional Npr3-CreER and Col1a2-CreER, respectively. For easy-to-recombine alleles such as R26-tdTomato, there was no significant difference in recombination efficiency between sCreER and the conventional CreER. However, for alleles that were relatively inert for recombination such as R26-Confetti, R26-LZLT, R26-GFP, or VEGFR2flox/flox alleles, sCreER showed a significantly higher efficiency in recombination compared with conventional CreER in endocardial cells or fibroblasts. Compared with conventional CreER, sCreER significantly enhances the efficiency of recombination to induce gene expression or gene deletion, allowing temporal yet effective in vivo genomic modification for studying gene function in specific cell lineages.

Author Correction: Lung regeneration by multipotent stem cells residing at the bronchioalveolar-duct junction.

In the version of this article initially published, the following grant numbers and recipients were missing from the Acknowledgements: XDB19000000 to H.J. and B.Z.; 81430066 and 31621003 to H.J.; 2017YFA0505500 to H.J.; and 15XD1504000 to H.J. The errors have been corrected in the HTML and PDF versions of the article.

Lung regeneration by multipotent stem cells residing at the bronchioalveolar-duct junction.

Characterizing the stem cells responsible for lung repair and regeneration is important for the treatment of pulmonary diseases. Recently, a unique cell population located at the bronchioalveolar-duct junctions has been proposed to comprise endogenous stem cells for lung regeneration. However, the role of bronchioalveolar stem cells (BASCs) in vivo remains debated, and the contribution of such cells to lung regeneration is not known. Here we generated a genetic lineage-tracing system that uses dual recombinases (Cre and Dre) to specifically track BASCs in vivo. Fate-mapping and clonal analysis showed that BASCs became activated and responded distinctly to different lung injuries, and differentiated into multiple cell lineages including club cells, ciliated cells, and alveolar type 1 and type 2 cells for lung regeneration. This study provides in vivo genetic evidence that BASCs are bona fide lung epithelial stem cells with deployment of multipotency and self-renewal during lung repair and regeneration.

Sonic hedgehog signaling regulates hypoxia/reoxygenation-induced H9C2 myocardial cell apoptosis.

The sonic hedgehog (Shh) signaling pathway has been reported to protect cells against hypoxia/reoxygenation (H/R) injury; however, the role of Shh and relevant molecular mechanisms remain unclear. In the present study, the rat cardiomyoblast cell line H9C2 was subjected to hypoxia and serum-starvation for 4 h. Cells were subsequently reoxygenated using 95% O2 and 5% CO2. Reverse transcription-quantitative polymerase chain reaction was performed to quantify the expression of Shh mRNA, while cell apoptosis was assessed using flow cytometry. Caspase-3 activity and p53 expression were measured by western blotting and an MTT assay was subsequently used to assess cell viability. In addition, reactive oxygen species levels were measured using dichlorofluorescein and H/R-induced changes in the activation of superoxide dismutase, catalase, phosphorylated-endothelial nitric oxide synthase, phosphorylated-protein kinase B (Akt) and mammalian target of rapamycin activation were assessed using western blotting. H/R treatment decreased the cell viability of H9C2 cells, but activated endogenous Shh signaling. The activation of Shh signaling protected H9C2 myocardial cells from H/R-induced apoptosis and restored cell viability. In the present study, Shh signaling was demonstrated to serve a protective role against H/R by activating the phosphoinositol 3-kinase (PI3K)/Akt pathway and promoting the expression of anti-oxidant enzymes to ameliorate oxidative stress. In summary, Shh signaling attenuated H/R-induced apoptosis through via the PI3K/Akt pathway.

Diosgenin Protects Rats from Myocardial Inflammatory Injury Induced by Ischemia-Reperfusion.

BACKGROUND Diosgenin, a phytosteroid sapogenin, has anti-inflammatory properties shown to reduce myocardial ischemia-reperfusion injury (MIRI). However, the specific mechanism by which this is achieved is not clear. This study investigated the protective effects of diosgenin on myocardial ischemia/reperfusion (I/R) and the potential anti-inflammatory mechanisms. MATERIAL AND METHODS Healthy adult male SD rats, body weight (b.w.) 250-280 g, were used to model ischemia-reperfusion injury (IRI) and were administered diosgenin (50 mg/kg and 100 mg/kg b.w.) intragastrically for 4 consecutive weeks before surgery. The left anterior descending artery (LAD) was ligated to induce myocardial ischemia for 30 min and reperfusion for 30 min, 60 min, and 120 min while relevant indicators were detected. RESULTS Both 50 mg and 100 mg diosgenin oral administration increased left ventricular developed pressure (LVDP) and maximum changing rate of ventricular pressure (±dp/dtmax), decreased left ventricular end-diastolic pressure (LVEDP), and myocardial enzyme markers. TTC staining suggested that diosgenin reduced myocardial infarct size in the rat model. Pathological results showed that myocardial ischemia and inflammation were alleviated by diosgenin. In addition, the increased expression of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1ß) in serum, and myeloperoxidase (MPO) in myocardium were significantly suppressed by diosgenin administration. Diosgenin further inhibited the phosphorylation of transcription factor NF-κB and modulated the expression of downstream inflammatory cytokines by regulating the activation of p38-MAPK and JNK pathways. CONCLUSIONS Results demonstrate diosgenin plays an anti-inflammatory role in the protection of MIRI through regulation of p38-MAPK and JNK pathways and phosphorylation of NF-κB.

Fibroblasts in an endocardial fibroelastosis disease model mainly originate from mesenchymal derivatives of epicardium.

Endocardial fibroelastosis (EFE) refers to the thickening of the ventricular endocardium as a result of de novo deposition of subendocardial fibrous tissue layers during neonatal heart development. The origin of EFE fibroblasts is proposed to be postnatal endocardial cells that undergo an aberrant endothelial-to-mesenchymal transition (EndMT). Genetic lineage tracing of endocardial cells with the inducible endocardial Cre line Npr3-CreER and the endothelial cell tracing line Cdh5-CreER on an EFE-like model did not reveal any contribution of neonatal endocardial cells to fibroblasts in the EFE-like tissues. Instead, lineage tracing of embryonic epicardium by Wt1-CreER suggested that epicardium-derived mesenchymal cells (MCs) served as the major source of EFE fibroblasts. By labeling MCs using Sox9-CreER, we confirmed that MCs of the embryonic heart expand and contribute to the majority of neonatal EFE fibroblasts. During this pathological process, TGFß signaling, the key mediator of fibroblasts activation, was highly upregulated in the EFE-like tissues. Targeting TGFß signaling by administration of its antagonist bone morphogenetic protein 7 effectively reduced fibroblast accumulation and tissue fibrosis in the EFE-like model. Our study provides genetic evidence that excessive fibroblasts in the EFE-like tissues mainly originate from the epicardium-derived MCs through epicardial to mesenchymal transition (EpiMT). These EpiMT-derived fibroblasts within the EFE-like tissues could serve as a potential therapeutic target.

Identification of a hybrid myocardial zone in the mammalian heart after birth.

Noncompaction cardiomyopathy is characterized by the presence of extensive trabeculations, which could lead to heart failure and malignant arrhythmias. How trabeculations resolve to form compact myocardium is poorly understood. Elucidation of this process is critical to understanding the pathophysiology of noncompaction disease. Here we use genetic lineage tracing to mark the Nppa+ or Hey2+ cardiomyocytes as trabecular and compact components of the ventricular wall. We find that Nppa+ and Hey2+ cardiomyocytes, respectively, from the endocardial and epicardial zones of the ventricular wall postnatally. Interposed between these two postnatal layers is a hybrid zone, which is composed of cells derived from both the Nppa+ and Hey2+ populations. Inhibition of the fetal Hey2+ cell contribution to the hybrid zone results in persistence of excessive trabeculations in postnatal heart. Our findings indicate that the expansion of Hey2+ fetal compact component, and its contribution to the hybrid myocardial zone, are essential for normal formation of the ventricular walls.Fetal trabecular muscles in the heart undergo a poorly described morphogenetic process that results into a solidified compact myocardium after birth. Tian et al. show that cardiomyocytes in the fetal compact layer also contribute to this process, forming a hybrid myocardial zone that is composed of cells derived from both trabecular and compact layers.

Protective effect of curcumin against myocardium injury in ischemia reperfusion rats.

CONTEXT: Curcumin has long been used as a condiment and a traditional medicine worldwide. OBJECTIVE: The current study investigates the possible protective effect of curcumin on heart function in myocardium ischemia-reperfusion (MIR) rats. MATERIALS AND METHODS: We fed Sprague-Dawley (SD) rats (10 in each group) either curcumin (10, 20 or 30 mg/kg/d) or saline. Twenty days later, the rats were subjected to myocardial injuries by ligating the left anterior descending coronary artery (60 min), and subsequently, the heart (3 h) reperfused by releasing the ligation. Then, lipid profile, lipid peroxidation products, antioxidant enzymes and gene expression were assessed in myocardium tissue. RESULTS: Only the rats that were supplemented with curcumin (10, 20 or 30 mg/kg/d) showed significant (p < 0.05) reductions in oxidative stress (3-fold), infarct size (2.5-fold), which was smaller than that of the control group. The percentage of infarct size in MIR rats with curcumin at 10, 20 or 30 mg/kg/d decreased (from 49.1% to 18.3%) compared to ischemia-reperfusion (I/R). The enhanced phosphorylation of STAT3 was further strengthened by curcumin (10, 20 or 30 mg/kg/d) in a dose-dependent manner. DISCUSSION AND CONCLUSION: Curcumin intake might reduce the risk of coronary heart disease by stimulating JAK2/STAT3 signal pathway, decreasing oxidative damage and inhibiting myocardium apoptosis.

Eupatilin inhibits the apoptosis in H9c2 cardiomyocytes via the Akt/GSK-3ß pathway following hypoxia/reoxygenation injury.

Eupatilin, a pharmacologically active flavone derived from the Artemisia plant species, has been reported to have anti-oxidant, anti-inflammatory, anti-allergic, and neuroprotective activities against cerebral ischemia/reperfusion (I/R). However, the role of eupatilin in myocardial I/R injury remains unclear. In the present study, we aimed to investigate the potential molecular mechanisms against hypoxia/reoxygenation (H/R) induced cardiomyocytes apoptosis in vitro. Our results showed that eupatilin markedly improved the cell viability and decreased lactate dehydrogenase (LDH) release. Eupatilin also suppressed oxidative stress and apoptosis in H9c2 cells after myocardial I/R injury. Furthermore, eupatilin obviously increased the phosphorylation of Akt and GSK-3ß in H9c2 cells. Our results suggested that eupatilin could provide significant cardioprotection against myocardial I/R injury, and the potential mechanisms might involve inhibition of cardiomyocyte apoptosis through activating the Akt/GSK-3ß signaling pathway.

Genetic lineage tracing identifies in situ Kit-expressing cardiomyocytes.

Cardiac cells marked by c-Kit or Kit, dubbed cardiac stem cells (CSCs), are in clinical trials to investigate their ability to stimulate cardiac regeneration and repair. These studies were initially motivated by the purported cardiogenic activity of these cells. Recent lineage tracing studies using Kit promoter to drive expression of the inducible Cre recombinase showed that these CSCs had highly limited cardiogenic activity, inadequate to support efficient cardiac repair. Here we reassess the lineage tracing data by investigating the identity of cells immediately after Cre labeling. Our instant lineage tracing approach identifies Kit-expressing cardiomyocytes, which are labeled immediately after tamoxifen induction. In combination with long-term lineage tracing experiments, these data reveal that the large majority of long-term labeled cardiomyocytes are pre-existing Kit-expressing cardiomyocytes rather than cardiomyocytes formed de novo from CSCs. This study presents a new interpretation for the contribution of Kit(+) cells to cardiomyocytes and shows that Kit genetic lineage tracing over-estimates the cardiogenic activity of Kit(+) CSCs.

SALVIANOLIC ACID B ALLEVIATING MYOCARDIUM INJURY IN ISCHEMIA REPERFUSION RATS.

BACKGROUND: Salvia miltiorrhiza (SM) Bunge is one of the widely-used Chinese medicinal herbs. Salvianolic acid B (Sal B), a bioactive compound isolated from the Chinese herb Radix Salviae Miltiorrhizae, has been reported to exhibit anti-inflammatory and anti-oxidantive effects. MATERIAL AND METHOD: To study the cardioprotective effects of salvianolic acid B (Sal B) on acute myocardial ischemia reperfusion (MIR) injury rats, on the basis of this investigation, the possible mechanism of salvianolic acid B was elucidated. Male Sprague- Dawley rats (200-220 g) were randomly divided into five groups: sham-operated, MIR, MIR + Sal B (10 mg/kg/day, orally), MIR + Sal B (20 mg/kg/ day, orally) and MIR + Sal B (30 mg/kg/ day, orally). Before operation, the foregoing groups were pretreated with homologous drug once a day for 7 days, respectively. After twelve hours in MIR, the cardioprotective effects of SPJ were evaluated by infarct size, biochemical values, and the antioxidative and antiapoptotic relative gene expressions. RESULTS: Sal B significantly improved heart function and decreased infarct size; remarkably decreased levels of serum TNF-α and IL-Ιß levels, increased contents of myocardium antioxidant enzymes activities; western blot results showed that Sal B ameliorate the increased Bax and caspase-3 protins expressions and decreased Bcl-2 proteins expression and ratios of Bcl-2 to Bax. CONCLUSION: In ischemic myocardium, oxidative stress caused the overgeneration and accumulation of reactive oxygen species (ROS), which was central of cardiac ischemic injury. Sal B exerted beneficially cardioprotective effects on myocardial ischemia injury rats, mainly scavenging oxidative stress-triggered overgeneration and accumulation of ROS, alleviating myocardial ischemia injury and cardiac cell death. List of abbreviations: salvianolic acid B (Sal B); myocardial ischemia reperfusion (MIR); reactive oxygen species (ROS); Left ventricular end-diastolic pressure (LVEDP); left ventricular end-diastolic volume (LVEDV); Malondialdehyde (MDA); superoxide dismutase (SOD); catalase (CAT); Glutathione peroxidase (GSH-Px); glutathione reductase (GR).

Apelin-13 protects the heart against ischemia-reperfusion injury through the RISK-GSK-3ß-mPTP pathway.

INTRODUCTION: Apelin plays an important role in the protection against myocardial ischemia-reperfusion (I/R) injury, while the mechanism still remains unclear. In the current study, we aimed to evaluate the protective effect of apelin-13, and the main mechanism. MATERIAL AND METHODS: The in vivo I/R injury model (Sprague-Dawley rat) was established, then infarct size, expression levels of phospho-protein kinase B (p-Akt), phospho-extracellular signal-regulated kinase (p-ERK) and phospho-glycogen synthase kinase-3ß (p-GSK-3ß) were measured. The fluorescence intensity of tetramethylrhodamine ethyl ester perchlorate (TMRE) of the isolated myocardial cells was determined to evaluate the opening of the mitochondrial permeability transition pore (mPTP) caused by oxidant stress and hypoxia/reoxygenation. RESULTS: For the established I/R injury model, apelin-13 and SB216763 (GSK-3ß inhibitor) significantly reduced the infarct size (p < 0.05), which could be abolished by LY294002 (PI3K inhibitor), PD98059 (MEK inhibitor) and atractyloside (mPTP accelerator). The enhanced expression levels of p-Akt, p-ERK and p-GSK-3ß caused by apelin-13 (p < 0.05) could be counteracted by LY294002 and PD98059. The reduced fluorescence intensity of TMRE in the H2O2/apelin-13 and H2O2/SB216763 treated groups was significantly lower (p < 0.05), indicating that apelin-13 and SB216763 could reduce the decline in mitochondrial membrane potential caused by oxidant stress, and the fluorescence intensity in the hypoxia/reoxygenation + apelin-13 group was significantly lower (p < 0.05), which suggested that apelin-13 could inhibit the mitochondrial membrane potential changes induced by hypoxia/reoxygenation. CONCLUSIONS: The protective mechanism of apelin-13 might be that inactivation of GSK-3ß could inhibit the opening of mPTP by activating PI3K/Akt and ERK1/2 involved in the reperfusion injury salvage kinase (RISK) pathway.

Glucagon-like peptide-1 protects against cardiac microvascular endothelial cells injured by high glucose.

OBJECTIVE: To investigate the protective effect of glucagon-like peptid-1 (GLP-1) against cardiac microvascular endothelial cell (CMECs) injured by high glucose. METHODS: CMECs were isolated and cultured. Superoxide assay kit and dihydroethidine (DHE) staining were used to assess oxidative stress. TUNEL staining and caspase 3 expression were used to assess the apoptosis of CMECs. H89 was used to inhibit cAMP/PKA pathway; fasudil was used to inhibit Rho/ROCK pathway. The protein expressions of Rho, ROCK were examined by Western blot analysis. RESULTS: High glucose increased the production of ROS, the activity of NADPH, the apoptosis rate and the expression level of Rho/ROCK in CMECs, while GLP-1 decreased high glucose-induced ROS production, the NADPH activity and the apoptosis rate and the expression level of Rho/ROCK in CMECs, the difference were statistically significant (P<0.05). CONCLUSIONS: GLP-1 could protect the cardiac microvessels against oxidative stress and apoptosis. The protective effects of GLP-1 are dependent on downstream inhibition of Rho through a cAMP/PKA-dependent manner, resulting in a subsequent decrease in the expression of NADPH oxidase.