IGFBP‐4 enhances VEGF‐induced angiogenesis in a mouse model of myocardial infarction

Vascular endothelial growth factor (VEGF) is a well‐known angiogenic factor, however its ability in promoting therapeutic angiogenesis following myocardial infarction (MI) is limited. Here, we aimed to investigate whether dual treatment with insulin‐like growth factor binding protein‐4 (IGFBP‐4), an agent that protects against early oxidative damage, can be effective in enhancing the therapeutic effect of VEGF following MI. Combined treatment with IGFBP‐4 enhanced VEGF‐induced angiogenesis and prevented cell damage via enhancing the expression of a key angiogenic factor angiopoietin‐1. Dual treatment with the two agents synergistically decreased cardiac fibrosis markers collagen‐I and collagen‐III following MI. Importantly, while the protective action of IGFBP‐4 occurs at an early stage of ischemic injury, the action of VEGF occurs at a later stage, at the onset angiogenesis. Our findings demonstrate that VEGF treatment alone is often not enough to protect against oxidative stress and promote post‐ischemic angiogenesis, whereas the combined treatment with IGFBP4 and VEGF can utilize the dual roles of these agents to effectively protect against ischemic and oxidative injury, and promote angiogenesis. These findings provide important insights into the roles of these agents in the clinical setting, and suggest new strategies in the treatment of ischemic heart disease.     

Intracoronary application of nicorandil regulates the inflammatory response induced by percutaneous coronary intervention

Intracoronary application of nicorandil can effectively reduce the myocardial no‐reflow (MNR) after percutaneous coronary intervention (PCI). We sought to investigate the mechanisms of nicorandil in preventing MNR, besides that of dilating the coronary microvasculature. A total of 60 patients undergoing PCI were enrolled and randomly divided into a nicorandil group and a control group. Before PCI, 2 mg of nicorandil or an equal volume of normal saline was injected into the coronary artery. Blood samples were collected before, 24 hours and 1 week after PCI and inflammatory cytokines were tested. In the control group, the expression of pro‐inflammatory cytokines was significantly increased, while the anti‐inflammatory cytokines were decreased 24 hours after PCI. In contrast, these changes were reversed in the nicorandil group, indicating that nicorandil regulated the inflammatory response induced by PCI. Then, proteomic analysis was performed to further elucidate the potential mechanisms. A total of 53 differentially expressed proteins (DEPs) were found 24 hours after PCI in the control group, and the changes of these relevant genes were reversed in the nicorandil group. These DEPs were significantly enriched in the inflammatory pathways. In conclusion, the intracoronary application of nicorandil before PCI can regulate the inflammatory responses induced by PCI, which might be an important mechanism of nicorandil in preventing MNR.     

Down‐regulation of Suv39h1 attenuates neointima formation after carotid artery injury in diabetic rats

Patients with diabetes have an increased risk of vascular complications. Suv39h1, a histone methyltransferase, plays a protective role against myocardial injury in diabetes. Herein, we intend to explore whether Suv39h1 could affect neointimal formation after vascular injury in diabetic rats and reveal the underlying mechanism. In this study, we generated adenovirus expressing Suv39h1 as well as lentivirus expressing Suv39h1‐targeting shRNA and evaluated the significance of Suv39h1 in vascular smooth muscle cells (VSMCs) under diabetic conditions. In vitro, we examined proliferative and migratory behaviours as well as the underlying signalling mechanisms in VSMCs in response to high glucose treatment. In vivo, we induced diabetes in SD rats with streptozocin and established the common carotid artery balloon injury model. Suv39h1 was found to be both necessary and sufficient to promote VSMC proliferation and migration under high glucose conditions. We observed corresponding changes in intracellular signalling molecules including complement C3 and phosphor‐ERK1/2. However, either up‐regulating or down‐regulating Suv39h1, phosphor‐p38 level was not significantly affected. Consistently, Suv39h1 overexpression led to accelerated neointima formation, while knocking down Suv39h1 reduced it following carotid artery injury in diabetic rats. Using microarray analyses, we showed that altering the Suv39h1 level in vivo dramatically altered the expression of myriad genes mediating different biological processes and molecular function. This study reveals the novel role of Suv39h1 in VSMCs of diabetes and suggests its potential role as a therapeutic target in diabetic vascular injury.     

An extracellular vesicle epitope profile is associated with acute myocardial infarction

The current standard biomarker for myocardial infarction (MI) is high‐sensitive troponin. Although powerful in clinical setting, search for new markers is warranted as early diagnosis of MI is associated with improved outcomes. Extracellular vesicles (EVs) attracted considerable interest as new blood biomarkers. A training cohort used for diagnostic modelling included 30 patients with STEMI, 38 with stable angina (SA) and 30 matched‐controls. Extracellular vesicle concentration was assessed by nanoparticle tracking analysis. Extracellular vesicle surface‐epitopes were measured by flow cytometry. Diagnostic models were developed using machine learning algorithms and validated on an independent cohort of 80 patients. Serum EV concentration from STEMI patients was increased as compared to controls and SA. EV levels of CD62P, CD42a, CD41b, CD31 and CD40 increased in STEMI, and to a lesser extent in SA patients. An aggregate marker including EV concentration and CD62P/CD42a levels achieved non‐inferiority to troponin, discriminating STEMI from controls (AUC = 0.969). A random forest model based on EV biomarkers discriminated the two groups with 100% accuracy. EV markers and RF model confirmed high diagnostic performance at validation. In conclusion, patients with acute MI or SA exhibit characteristic EV biomarker profiles. EV biomarkers hold great potential as early markers for the management of patients with MI.     

LncRNA H19 ameliorates myocardial infarction‐induced myocardial injury and maladaptive cardiac remodelling by regulating KDM3A

Myocardial infarction (MI) remains the leading cause of morbidity and mortality worldwide, and novel therapeutic targets still need to be investigated to alleviate myocardial injury and the ensuing maladaptive cardiac remodelling. Accumulating studies have indicated that lncRNA H19 might exert a crucial regulatory effect on cardiovascular disease. In this study, we aimed to explore the biological function and molecular mechanism of H19 in MI. To investigate the biological functions of H19, miRNA‐22‐3p and KDM3A, gain‐ and loss‐of‐function experiments were performed. In addition, bioinformatics analysis, dual‐luciferase reporter assays, RNA immunoprecipitation (RIP) assays, RNA pull‐down assays, quantitative RT‐PCR and Western blot analyses as well as rescue experiments were conducted to reveal an underlying competitive endogenous RNA (ceRNA) mechanism. We found that H19 was significantly down‐regulated after MI. Functionally, enforced H19 expression dramatically reduced infarct size, improved cardiac performance and alleviated cardiac fibrosis by mitigating myocardial apoptosis and decreasing inflammation. However, H19 knockdown resulted in the opposite effects. Bioinformatics analysis and dual‐luciferase assays revealed that, mechanistically, miR‐22‐3p was a direct target of H19, which was also confirmed by RIP and RNA pull‐down assays in primary cardiomyocytes. In addition, bioinformatics analysis and dual‐luciferase reporter assays also demonstrated that miRNA‐22‐3p directly targeted the KDM3A gene. Moreover, subsequent rescue experiments further verified that H19 regulated the expression of KDM3A to ameliorate MI‐induced myocardial injury in a miR‐22‐3p‐dependent manner. The present study revealed the critical role of the lncRNAH19/miR‐22‐3p/KDM3A pathway in MI. These findings suggest that H19 may act as a potential biomarker and therapeutic target for MI.     

Cardioprotective effect of isorhamnetin against myocardial ischemia reperfusion (I/R) injury in isolated rat heart through attenuation of apoptosis

In this study, we investigated the effects of isorhamnetin on myocardial ischaemia reperfusion (I/R) injury in Langendorff-perfused rat hearts. Isorhamnetin treatment (5, 10 and 20 μg/mL) significantly alleviated cardiac morphological injury, reduced myocardial infarct size, decreased the levels of marker enzymes (LDH and CK) and improved the haemodynamic parameters, reflected by the elevated levels of the left ventricular developed pressure (LVDP), coronary flow (CF) and the maximum up/down velocity of left ventricular pressure (+dp/dt_max). Moreover, isorhamnetin reperfusion inhibited apoptosis of cardiomyocytes in the rats subjected to cardiac I/R in a dose-dependent manner concomitant with decreased protein expression of Bax and cleaved-caspase-3, as well as increased protein expression of Bcl-2. In addition, I/R-induced oxidative stress was manifestly mitigated by isorhamnetin treatment, as showed by the decreased malondialdehyde (MDA) level and increased antioxidant enzymes activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px). These results indicated that isorhamnetin exerts a protective effect against I/R-induced myocardial injury through the attenuation of apoptosis and oxidative stress.     

MT2A对脂多糖介导的人肺毛细血管内皮细胞损伤的保护作用

目的:探索不同浓度的金属硫蛋2A(Metallothionein 2A, MT2A)对脂多糖(Lipopolysaccharid, LPS)介导的人肺微血管内皮细胞损伤的保护作用。方法:培养人肺毛细血管内皮细胞株(Human lung microvascular endothelial cells, HPMVECs),经过一定浓度LPS溶液进行刺激后,利用不同浓度的MT2A与对照组共同培养,一段时间后观察炎性介质IL-6、TNF-α释放的量及荧光显微镜观察组HPMVECs骨架形态变化。结果:各组TNF-α浓度均在0 h最低,随之逐渐升高,到6 h达到高峰;从各时间点来看,除0 h各组TNF-α浓度无显著差异外(F=0.717, P=0.549),其余各时间点B1、B2、B3均显著高于A组(均P0.05)。各组中IL-6浓度均在0 h最低,A组在2 h达到高峰,随后逐渐下降;B1组在4 h达到高峰,随之下降;B2、B3组从0 h开始逐渐升高,到6 h达到峰值;从各时间点来看,除0 h各处理因素无显著差异外(F=2.341, P=0.092),其余各时间点B1、B2、B3均低于A组(均P0.05)。A组6 h小时后纤维状肌动蛋白(F-actin)明显解聚,分布明显减少,应力纤维排列紊乱或者消失;B1组、B2组、B3组6 h小时后,与A组相比,F-actin的分布明显较多,应力纤维排列较为整齐。结论:LPS刺激人肺毛细血管内皮细胞有明显损伤效应,加入MT2A后细胞相关炎性因子释放量、细胞骨架损伤情况明显减轻,表明一定浓度的MT2A对LPS介导的肺毛细血管损伤有明显保护作用。     

阻断趋化因子CXCL10对脑缺血再灌注损伤及神经炎症的影响

目的:探讨趋化因子CXCL10在脑缺血再灌注损伤中对神经炎症的影响。方法:(1)线栓法建立脑缺血再灌注损伤大鼠模型,TTC染色检测梗死面积,Western blot检测CXCL10的表达;(2)建立小鼠神经瘤母细胞N2a氧糖剥夺/复氧(oxygen-glucose deprivation/reoxygenation,OGD/R)模型,通过CXCR3拮抗剂-NBI 74330阻断趋化因子CXCL10表达,Western blot检测CXCL10和CXCR3蛋白的表达;Real-time PCR检测CXCL10、CXCR3以及神经炎症因子TNF-α、IL-1β、IL-2 m RNA的表达。结果:(1)脑缺血再灌注(cerebral ischemia reperfusion injury,CIRI)模型大鼠脑梗死侧CXCR10的表达量显著高于其对侧和假手术组(P<0.05);(2)阻断CXCL10使得小鼠神经瘤母细胞N2a中CXCL10、CXCR3以及炎症因子TNF-α、IL-1β、IL-2的表达量均显著降低(P<0.05);(3)阻断CXCL10使得小鼠神经瘤母细胞细胞凋亡率降低(P<0.05)。结论:抑制CXCL10降低了氧糖剥夺模型细胞炎症因子的表达,表明阻断CXCL10可能通过减轻神经炎症在脑缺血再灌注损伤中发挥保护作用。     

不同剂量舒芬太尼对心脏瓣膜置换术患者应激反应、炎性因子及心肌损伤的影响

目的:探讨不同剂量舒芬太尼对心脏瓣膜置换术患者应激反应、炎性因子及心肌损伤的影响。方法:根据随机数字表法将100例行心脏瓣膜置换术的患者分为低剂量组(n=33,舒芬太尼剂量为1.0μg/kg)、中剂量组(n=33,舒芬太尼剂量为1.5μg/kg)以及高剂量组(n=34,舒芬太尼剂量为2.0μg/kg),比较三组患者应激反应、炎性因子、心肌损伤等指标的变化以及围术期指标情况。结果:中剂量组、高剂量组麻醉诱导后(T1)、插管后1 min(T2)、插管后5 min(T3)、插管后10 min(T4)时间点心率(HR)、平均动脉压(MAP)均低于低剂量组同时间点,且高剂量组低于中剂量组(P<0.05)。与低剂量组比较,中剂量组、高剂量组阻断后30 min(T6)、开主动脉后2h(T7)以及术后1d(T8)时间点白介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)均降低(P<0.05)。与低剂量组比较,中剂量组、高剂量组体外循环停机2h(T9)、体外循环停机8h(T10)、体外循环停机24h(T11)、体外循环停机48h(T12)时间点心肌肌钙蛋白I(cTnI)、肌酸磷酸激酶同工酶(CK-MB)均降低(P<0.05)。低剂量组、中剂量组重症监护室(ICU)滞留时间、拔管时间显著短于高剂量组(P<0.05),而三组心血管不良事件发生率比较差异无统计学意义(P>0.05)。结论:给予1.0μg/kg舒芬太尼麻醉的患者应激反应小,1.5μg/kg、2.0μg/kg舒芬太尼可更好地控制心脏瓣膜置换术患者炎性反应,同时对患者心肌损伤有一定的保护作用,但2.0μg/kg舒芬太尼会延长患者ICU滞留时间、拔管时间。     

心肌带收缩率与急性心肌梗死患者左心室收缩功能关系

目的:急性前壁心肌梗死明显影响室间隔收缩率和左心室射血分数(left ventricular ejection fraction LVEF)。本文旨在探讨心肌带降段及升段收缩率与急性前壁心肌梗死患者LVEF的相关性。方法:收集2015年4月-2017年2月在心内科住院的急性前壁心肌梗死患者36例,正常对照组患者39例。所有患者取左心室长轴M型超声心动图,测量室间隔收缩率、升段收缩率及降段收缩率。心肌梗死左心室射血分数采用双平面Simpson's法计算。结果:与正常对照组相比,心肌梗死组患者舒张末期心肌带升段厚度没有统计学差异(P=0.69),收缩末期升段厚度(P=0.014)更薄、升段收缩率(P0.01)明显降低;心肌梗死组舒张末期降段厚度(P0.01)更薄、收缩末期降段厚度(P0.01)更薄、降段收缩率(P0.01)明显降低;心肌梗死组左心室射血分数与降段收缩率(r~2=0.13,P=0.026)、室间隔增厚率(r~2=0.19,P0.01)呈正相关,与升段收缩率没有相关性(P0.05)。正常对照组左心室射血分数与室间隔增厚率、降段增厚率及升段增厚率无相关性。经过相关分析,筛选出与心肌梗死LVEF的相关因素,进一步经逐步回归分析,得多元线性回归方程为LVEF=48.206+18.914*LVDD(cm)-25.414*LVSD(cm)。结论:急性前壁心肌梗死室间隔降段收缩率明显受损,与左心室射血分数降低有关。多元线性回归方程可估算前壁心肌梗死LVEF。