Tie-Bing Zhu

Coexpression of VEGF and angiopoietin-1 promotes angiogenesis and cardiomyocyte proliferation reduces apoptosis in porcine myocardial infarction (MI) heart

VEGF and angiopoietin-1 (Ang1) are two major angiogenic factors being investigated for the treatment of myocardial infarction (MI). Targeting VEGF and Ang1 expression in the ischemic myocardium can increase their local therapeutic effects and reduce possible adverse effects. Adeno-associated viral vectors (AAVs) expressing cardiac-specific and hypoxia-inducible VEGF [AAV-myosin light chain-2v (MLC)VEGF] and Ang1 (AAV-MLCAng1) were coinjected (VEGF/Ang1 group) into six different sites of the porcine myocardium at the peri-infarct zone immediately after ligating the left descending coronary artery. An identical dose of AAV-Cytomegalovirus (CMV)LacZ or saline was injected into control animals. AAV genomes were detected in the liver in addition to the heart. RT-PCR, Western blotting, and ELISA analyses showed that VEGF and Ang1 were predominantly expressed in the myocardium in the infarct core and border of the infarct heart. Gated single-photon emission computed tomography analyses showed that the VEGF/Ang1 group had better cardiac function and myocardial perfusion at 8 wk than at 2 wk after vector injection. Compared with the saline and LacZ controls, the VEGF/Ang1 group expressed higher phosphorylated Akt and Bcl-xL, less Caspase-3 and Bad, and had higher vascular density, more proliferating cardiomyocytes, and less apoptotic cells in the infarct and peri-infarct zones. Thus, cardiac-specific and hypoxia-induced coexpression of VEGF and Ang1 improves the perfusion and function of porcine MI heart through the induction of angiogenesis and cardiomyocyte proliferation, activation of prosurvival pathways, and reduction of cell apoptosis.

A novel approach to transplanting bone marrow stem cells to repair human myocardial infarction: delivery via a noninfarct-relative artery.

Bone marrow stem cells are able to repair infarcted human myocardium following intracoronary transplantation via the infarct-relative artery. However, traditional reperfusion strategies fail to open the artery in some patients, making effective delivery impossible. Our previous study demonstrated a safe and efficient approach to delivering bone marrow stem cells via a noninfarcted artery in an animal myocardial infarction model. The objective of the present study was to evaluate the safety and feasibility of autologous bone marrow mesenchymal stem cell transplantation via such an approach in patients with acute myocardial infarction (AMI). Sixteen patients with anterior AMI who had successfully undergone percutaneous coronary intervention (PCI) were enrolled in this pilot, randomized study. Three weeks after PCI, cultured bone marrow mesenchymal stem cells were injected into the myocardium via either the infarct-relative artery (left anterior descending branch artery, LAD) or a noninfarct-relative artery (right coronary artery, RCA). The safety and feasibility of the cell infusion were evaluated during the procedure and during 6 months of follow-up. In addition, 2D echocardiography, technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) and 18F-deoxyglucose single photon emission computed tomography were employed to examine cardiac function, myocardial perfusion, and viable cardiomyocytes, respectively, at day 4 after PCI and 6 months after the cell infusion. There were no arrhythmia and any other side-effects, including infections, allergic reactions or adverse clinical events, during, immediately after, or 6 months after cell transplantation. Cardiac function and myocardial perfusion had improved 6 months after PCI/bone marrow stem cells transplantation. Viable cardiomyocytes metabolism was detected in the infarcted areas in both groups after the cell infusion, as demonstrated by 18F-deoxyglucose. Intracoronary infusion of autologous bone marrow mesenchymal stem cells via a noninfarct-relative artery appears safe and feasible in the treatment of patients with AMI.

Testosterone is negatively associated with the severity of coronary atherosclerosis in men.

This study aimed to determine whether plasma testosterone is associated with the severity of coronary atherosclerosis in a group of 803 men who underwent elective coronary angiography. Testosterone levels were measured in 803 male patients who were categorized into three groups according to testosterone level tertiles. All patients underwent elective coronary angiography, and the severity of coronary artery disease (CAD) was determined by the Gensini score. Moreover, patients were classified into two groups according to Gensini scores (score ≤26 and score >26) using the median values as cutoff points. The plasma testosterone levels were measured by an ELISA kit. The level of testosterone was negatively associated with the Gensini score (r=-0.188; P=0.000). A multiple linear regression analysis revealed that testosterone was an independent risk factor for the Gensini score (β=-0.110; P=0.002) after adjusting for confounding covariates. In a multivariate logistic regression model, the severity of CAD was shown to be significantly lower in the third tertile (highest) of testosterone compared to the first tertile (lowest) of testosterone (odds ratio (OR)=0.465; 95% confidence interval (CI): 0.327-0.662; P=0.000). In this study, patients with lower testosterone levels had higher Gensini scores in a group of 803 men who underwent elective coronary angiography. Additional studies are needed to clarify the direction of causality and possible underlying mechanisms.

HEPATOCYTE GROWTH FACTOR PLAYS A CRITICAL ROLE IN THE REGULATION OF CYTOKINE PRODUCTION AND INDUCTION OF ENDOTHELIAL PROGENITOR CELL MOBILIZATION: A PILOT GENE THERAPY STUDY IN PATIENTS WITH CORONARY HEART DISEASE

1 There is growing evidence of the beneficial effects of hepatocyte growth factor (HGF) in myocardial infarction, heart failure and occlusive peripheral arterial disease. The aim of the present study was to evaluate the effects of intracoronary administration of an adenovirus vector encoding the human HGF gene (Ad‐HGF) on serum levels of cytokines and mobilization of CD34+ and CD117+ cells in patients with coronary heart disease. 2 Twenty‐one patients with severe coronary artery disease were recruited to the study: 11 patients received both a stent and administration of Ad‐HGF; the remaining 10 patients received a stent alone and served as the control group. Blood samples were obtained from the femoral vein before and then 6 and 24 h, 3 and 6 days and 2 weeks after treatment for the isolation of serum and peripheral blood mononuclear cells. Intracoronary administration of Ad‐HGF in patients with coronary heart disease resulted in high levels of HGF gene expression, as well as its receptor c‐met, compared with the control group, as demonstrated by real‐time reverse transcription–polymerase chain reaction. In addition, serum levels of HGF, vascular endothelial growth factor, monocyte chemoattractant protein‐1 and interleukin (IL)‐10 were increased and serum levels of IL‐8 were decreased in patients administered Ad‐HGF compared with the control group. The percentage of CD34+ and CD117+ cells in the peripheral blood increased in patients administered Ad‐HGF. 3 In conclusion, HGF gene therapy may play an important role in the regulation of cytokines and the induction of endothelial progenitor cell mobilization in patients with coronary heart disease.

Toxic effects of a high dose of non-ionic iodinated contrast media on renal glomerular and aortic endothelial cells in aged rats in vivo

Iodinated contrast media (CM) can induce apoptosis and necrosis of renal tubular cells. The injuries of endothelial cells induced by CM on the systemic condition have not been fully understood. To assess the toxic effects of non-ionic CM on the glomerular and aortic endothelial cells, iopromide and iodixanol, two kinds of representative non-ionic CM, were used for the in vivo study. Sixty aged rats were respectively received the agents or normal sodium intravascularly. No obvious apoptosis and morphological change was detected in the glomerular and aortic endothelial cells apart from renal tubules after CM administration. However, expressions of the nitric oxide synthase (eNOS) in glomerular endothelium were decreased at 12h after CM injection. Furthermore, plasma creatinine and endothelin-1 were increased and plasma nitric oxide (NO) was decreased significantly after CM administration. However, we failed to observe the significant increase of plasma von Willebrand Factor. These results suggest that non-ionic iodinated CM do not induce apoptosis and necrosis of glomerular and aortic endothelial cells in vivo. Decreased eNOS expression and increased plasma endothelin-1 may be involved in non-ionic iodinated CM-induced endothelial dysfunction and kidney injury.

Renin-Angiotensin-Aldosterone System Gene Polymorphisms and Coronary Artery Disease: Detection of Gene-Gene and Gene-Environment Interactions

Objective: The objective of this study was to explore the association between coronary artery disease and genetic polymorphisms of the renin–angiotensin–aldosterone system (RAAS) pathway. In addition, we examined the interactions between demographic and lifestyle risk factors (environmental factors including age, sex, smoking status, alcohol intake) and RAAS polymorphisms on disease risk. Methods: A total of 1089 subjects who underwent coronary angiography were enrolled in this study. Eight RAAS polymorphisms were genotyped in this population: the G2350A (rs4343) polymorphism in exon 17 of the angiotensin converting enzyme (ACE) gene, 1166A→C (rs5186) and 573C/T (rs5182) in the angiotensin II type 1 receptor (AGTR1) gene, the -344C→T transversion (rs1799998) in the aldosterone synthase (CYP11B2) gene, and the G-217A (rs5049), G-6A (rs5051), M235T (rs699; T4072C), and T174M (rs4762; C3889T) polymorphisms in the angiotensinogen (AGT) gene. Subjects with coronary heart disease were defined as those with at least 50% stenosis in at least one major coronary artery, and, the severity of coronary atherosclerosis was defined by the Gensini scoring system. Results: Compared to the subjects with AA genotype, the subjects with AG + GG genotype of rs1799998 had significant lower gensini score (p=0.029). After adjusting for age, gender, cigarette smoking, and alcohol intake status, the AG genotype (OR 0.717 95%CI 0.541–0.950, p=0.021) and the AG + GG genotype (OR 0.730 95%CI 0.559–0.954, p=0.021) distributions of rs1799998 were significantly different between the cases and controls compare to the AA genotype. Subjects with three at-risk loci had increased risk of coronary artery disease compared to subjects carrying 0 or 1 risk-associated polymorphism (OR [95% CI]:1.579 [1.077–2.316], p=0. 019), and the significance of the association was not reduced after adjusting for age, sex, cigarette smoking, or alcohol intake (adjusted OR [95% CI]: 1.673 [1.116–2.507], p=0.013). The results of multifactor-dimensionality reduction analysis revealed an interaction effect of CYP11B2 -344C→T, age, and smoking status on the risk of coronary heart disease (training OR [95% CI]: 3.7685 [2.8463–4.9895], p<0.0001; testing OR [95% CI]: 2.7583 [1.2038–6.3203], p=0.015). Conclusions: Subjects who carried the G allele of the rs1799998 polymorphism significantly associated with coronary heart disease and severity of coronary atherosclerosis estimated by the Gensini score in the whole population of the study. And, multiple RAAS gene polymorphisms are associated with coronary artery disease. The interaction of the CYP11B2 -344C→T polymorphism (rs1799998), age, and smoking status is also associated with enhanced risk of coronary artery disease.

Interaction between microRNA expression and classical risk factors in the risk of coronary heart disease.

The aim of this study was to identify the synergistic effect of microRNA expression with classical risk factors of coronary heart disease (CHD) and to explore their diagnostic value for coronary stenotic lesions in subjects with CHD. Plasma samples were obtained from 66 subjects with CHD and from 58 control individuals. A quantitative reverse-transcription PCR (RT-qPCR) assay was conducted to confirm the relative expressions of the known CHD-related miRNAs. The severity of coronary atherosclerosis was based on the Gensini scoring system. The expression of miR-125b in plasma of the CHD group was lower than that of the non-CHD group (0.14 ± 0.09 vs. 0.18 ± 0.10, p = 0.055), and the miR-125b levels significantly decreased following an increasing Gensini score (P = 0.037). Spearman correlation analyses indicated the Gensini score was negatively associated with miR-125b (r = −0.215, p = 0.017). Of all the miRNAs, miR-125b showed the lowest AUC (0.405; 95% CI: 0.305 ~ 0.506, p = 0.070). We found several synergistic effects between miR-125b and classical risk factors, such as age, sex, CR, FBG and HDL-C; the proportion of CHD attributable to the interaction of miR-125b and age was as high as 80%. Therefore, miR-125b was shown to play an important role in individual’s susceptibility to developing CHD.

Zinc supplementation results in improved therapeutic potential of bone marrow-derived mesenchymal stromal cells in a mouse ischemic limb model.

BACKGROUND AIMS We wanted to determine whether zinc supplementation can inhibit bone marrow-derived mesenchymal stromal cell (MSC) apoptosis and enhance their tissue regenerative potential a in mouse ischemic hindlimb model. METHODS Rat bone marrow cells were cultured and the resulting MSC were passaged for 3-7 generations. The proliferation and apoptosis of MSC was examined by 3-[4,5-dimethyl-2-thiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry analysis. The activation of protein kinases B (Akt) was determined by Western blots. Vascular endothelial growth factor (VEGF) levels were examined by enzyme-linked immunosorbent assay. The mouse hindlimb ischemic model was established by ligating the right femoral artery. Mice received MSC, zinc-treated MSC or vehicle. The blood flow was assessed by laser Doppler imaging. The survival rate of donor cells was quantified by real-time polymerase chain reaction for the sex-determining region of the Y-chromosome (Sry). Angiogenesis was assessed by histochemical staining and immunofluoresence staining. RESULTS Supplementation with physiologic amounts of zinc caused a marked attenuation of cell apoptosis, enhanced cell viabilities, increased VEGF release and up-regulated Akt activation. Zinc-treated MSC delivered into ischemic hindlimbs resulted in significant improvements in limb blood perfusion by increased implanted MSC survival and stimulated angiogenesis. CONCLUSIONS This study demonstrates the potential of zinc supplement to enhance survival of engrafted MSC and ameliorate their tissue regenerative potential in a mouse ischemic hindlimb model.

Proinsulin Is an Independent Predictor of the Angiographical Characteristics of Coronary Atherosclerosis

Objective: The objective of this survey was to study the association between circulating proinsulin level and the severity of coronary atherosclerosis. Methods: The study population consisted of 1,039 consecutive patients (775 males and 264 females) who underwent coronary angiography for suspected or known coronary atherosclerosis. The patients’ anthropometric and plasma measurements including body mass index, blood pressure, blood lipid, blood glucose, and proinsulin level were performed. The severity of coronary atherosclerosis was defined by the Gensini’s score system. Results: When proinsulin level was examined as a categorical variable classified by quartile values, subjects with a high proinsulin level had significantly higher values of Gensini’s score than those with a low proinsulin level (p = 0.000). The Spearman correlation analysis suggests that the Gensini’s score was significantly correlated with proinsulin level (r = –0.177, p = 0.000). Multiple stepwise linear regression analysis demonstrated that glucose (β= 0.136, p = 0.000), age (β= 0.189, p = 0.000), proinsulin (β= 0.135, p=0.000), SBP (mm Hg) (β= –0.061, p = 0.043), fasting low-density lipoprotein cholesterol (mmol/l) (β= 0.141, p = 0.003), and total cholesterol (β= –0.105, p = 0.029) are significantly independently associated with the Gensini’s score. Conclusions: Proinsulin is a strong and statistically highly significant pre- dictor of coronary atherosclerosis independent of the other major risk factors including age, body mass index, blood pressure, fasting blood glucose, and blood lipid. The exact mechanisms need further study.

Time distribution of the onset of chest pain in subjects with acute ST-elevation myocardial infarction: an eight-year, single-center study in China.

Objective The objective of this study was to explore the time distribution patterns of the onset of chest pain in subjects with acute ST-elevation myocardial infarction in a Chinese population. Methods A total of 1467 patients with acute ST-elevation myocardial infarction were enrolled from 2003 to 2010. The hourly, daily, monthly, seasonal and day-of-week fluctuations in the prevalence of acute ST-elevation myocardial infarction were analyzed. Results A peak was found between the morning hours of 07:31 and 08:30. A second peak was observed between 14:31 and 15:30, and a third peak was found between 23:31 and 00:30 (p<0.001). The monthly maximum was recorded in November and the minimum was in April (p<0.001). The number of daily cases was greatest in autumn and lowest in the spring (p = 0.001). Day-of-the-week variations of ST-elevation acute myocardial infarction were not found, except in patients more than 75-years-old. Conclusions Periodic variations in the frequency of ST-elevation acute myocardial infarction in Chinese patients showed significant differences with regard to diurnal, monthly and seasonal patterns. The exact mechanisms underlying these circadian variations require further study.