Angiotensin II mediates urotensin II expression by hypoxia in cultured cardiac fibroblast.

BACKGROUND: Urotensin II plays a role in myocardial remodelling. Cardiac fibroblasts play a critical role in the development of cardiac fibrosis. The effect of hypoxia on urotensin II expression in cardiac fibroblasts is poorly understood. We sought to investigate the regulation of urotensin II by hypoxia in cardiac fibroblasts and the effect of angiotensin II in the interaction with urotensin II. METHODS AND RESULTS: Rat cardiac fibroblasts were cultured in hypoxic chamber. Hypoxia significantly increased urotensin II expression and reactive oxygen species (ROS) production in cultured cardiac fibroblasts. Hypoxia-induced increase in urotensin II protein and ROS was significantly attenuated after the addition of SP600125, JNK siRNA or N-acetylcysteine before hypoxia treatment. The phosphorylated JNK protein was induced by hypoxia and was abolished by pretreatment with SP600125, losartan (an angiotensin II receptor antagonist) or N-acetylcysteine. The increased urotensin II expression by exogenous addition of angiotensin II was similar to that by hypoxia. Addition of losartan and angiotensin II antibody before hypoxia almost completely inhibited the increase in urotensin II induced by hypoxia. Hypoxia significantly increased the secretion of angiotensin II from cardiac fibroblasts and increased the collagen I protein expression. Hypoxia significantly increased the urotensin II promoter activity by 4·3-fold as compared to normoxic control. Urotensin II siRNA almost completely attenuated the collagen I protein expression induced by hypoxia. CONCLUSIONS: Hypoxia-induced urotensin II expression in cardiac fibroblast is mediated by angiotensin II and through ROS and JNK pathway. Urotensin II is a mediator of angiotensin II-induced cardiac fibrosis under hypoxia.

Resistin contributes to neointimal formation via oxidative stress after vascular injury.

Resistin may play a major potential role in vascular remodelling and may contribute to atherogenesis. However, the role of VSMC (vascular smooth muscle cell)-derived resistin in neointimal formation is not well understood. We hypothesize that endogenous resistin derived from VSMCs may contribute to neointimal formation after vascular injury. VSMCs from thoracic aorta of adult Wistar rats were cultured. The carotid artery from adult Wistar rats was injured by balloon catheter. Resistin significantly increased migration and proliferation of VSMCs. Resistin siRNA (small interfering RNA) and resistin antibody significantly inhibited migration and proliferation of VSMCs induced by conditioned medium from stretched VSMCs. Resistin protein and mRNA expression significantly increased at 14 days after carotid injury. Resistin siRNA and NAC (N-acetylcysteine) significantly reduced resistin protein and mRNA expression induced by balloon injury. Carotid artery injury increased ROS (reactive oxygen species) production. Treatment with NAC and resistin siRNA decreased ROS production. The neointimal area was significantly increased after carotid injury and was significantly reduced by resistin siRNA and NAC. In conclusion, resistin increases migration and proliferation of VSMCs, and expression of resistin in carotid artery significantly increases after injury. Resistin siRNA attenuates neointimal formation after carotid injury partly through an antioxidative mechanism. Resistin may play a pivotal role in the pathogenesis of neointimal thickening after mechanical injury.

Incidence, predictors and outcomes of subacute stent thrombosis following primary stenting for ST-elevation myocardial infarction.

BACKGROUND/PURPOSE: Knowledge concerning subacute stent thrombosis (SST) following primary stenting for ST-elevation myocardial infarction (STEMI) is not widely available. We studied the incidence, predictors, and clinical outcomes of SST following STEMI. METHODS: We analyzed data from 455 consecutive patients who underwent primary stenting for STEMI. Baseline clinical characteristics, coronary angiographic features, medication and outcome were compared in patients with and without SST. RESULTS: SST occurred in 17 patients, and the incidence was 3.7%. Univariate predictors of SST were being a current smoker (53.0%vs. 82.4%, p = 0.01), Killip class >or= II (38.4%vs. 58.8%, p = 0.05), no coronary re-flow after stenting (6.2%vs. 17.6%, p = 0.05) and lack of coprescription with a statin (39.5%vs. 5.9%, p<0.01). After multivariate analysis, being a current smoker (odds ratio = 4.76; 95% confidence interval 1.20-18.95) and using statin therapy (odds ratio = 0.09; 95% confidence interval = 0.01-0.75) were independent correlates of SST. Patients with SST were associated with higher 30-day mortality (37.5%vs. 3.1%, p<0.01) and all-cause mortality (23.5%vs. 5.3%, p = 0.01) at long-term follow-up. CONCLUSION: Although SST is rare in patients with STEMI treated by primary stenting, it imparts a significantly higher mortality at short-term and long-term follow-up. Being a current smoker and the lack of co-prescription with a statin were associated with higher incidence of SST. Our results suggest initiation of statin therapy in patients with STEMI should be considered before discharge.

Mechanism of inhibitory effect of atorvastatin on resistin expression induced by tumor necrosis factor-alpha in macrophages.

Atorvastatin has been shown to reduce resistin expression in macrophages after pro-inflammatory stimulation. However, the mechanism of reducing resistin expression by atorvastatin is not known. Therefore, we sought to investigate the molecular mechanisms of atorvastatin for reducing resistin expression after proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha) stimulation in cultured macrophages. Cultured macrophages were obtained from human peripheral blood mononuclear cells. TNF-alpha stimulation increased resistin protein and mRNA expression and atorvastatin inhibited the induction of resistin by TNF-alpha. Addition of mevalonate induced resistin protein expression similar to TNF-alpha stimulation. However, atorvastatin did not have effect on resistin protein expression induced by mevalonate. SP600125 and JNK small interfering RNA (siRNA) completely attenuated the resistin protein expression induced by TNF-alpha and mevalonate. TNF-alpha induced phosphorylation of Rac, while atorvastatin and Rac-1 inhibitor inhibited the phosphorylation of Rac induced by TNF-alpha. The gel shift and promoter activity assay showed that TNF-alpha increased AP-1-binding activity and resistin promoter activity, while SP600125 and atorvastatin inhibited the AP-1-binding activity and resistin promoter activity induced by TNF-alpha. Recombinant resistin and TNF-alpha significantly reduced glucose uptake in cultured macrophages, while atorvastatin reversed the reduced glucose uptake by TNF-alpha. In conclusion, JNK and Rac pathway mediates the inhibitory effect of atorvastatin on resistin expression induced by TNF-alpha.

RNA interference for discoidin domain receptor 2 attenuates neointimal formation in balloon injured rat carotid artery.

OBJECTIVE: Discoidin domain receptor 2 (DDR2) plays potential roles in the regulation of collagen turnover mediated by smooth muscle cells (SMCs) in atherosclerosis. Little is known about the function of DDR2 in vascular system. We investigated whether inhibition of DDR2 by small interfering RNA (siRNA) can reduce neointimal formation after arterial injury. METHODS AND RESULTS: SMCs from thoracic aorta of adult Wistar rats were cultured. The carotid artery from adult Wistar rats was injured by balloon catheter. DDR2 significantly increased migration and proliferation of SMCs. DDR2 siRNA inhibited 86% of DDR2 protein expression in cultured SMCs. DDR2 protein and mRNA expression significantly increased at 14 days after carotid injury. DDR2 siRNA significantly reduced DDR2 protein and mRNA expression induced by balloon injury. The immunohistochemical stain demonstrated that DDR2 siRNA decreased MMP2 protein labeling induced by balloon injury, a pattern similar to that of DDR2 protein labeling. Neointimal area was significantly increased after carotid injury and was significantly reduced by DDR2 siRNA. CONCLUSIONS: DDR2 increases migration and proliferation of SMCs, and expression of DDR2 in carotid artery significantly increases after injury. DDR2 siRNA attenuates neointimal formation after carotid injury. DDR2 may play a pivotal role in the pathogenesis of neointimal thickening after mechanical injury.

Pericardial fluid and serum levels of vascular endothelial growth factor and endostatin in patients with or without coronary artery disease.

BACKGROUND/PURPOSE: Vascular endothelial growth factor (VEGF) and endostatin are related to ischemic heart disease. This study investigated pericardial fluid and serum levels of VEGF and endostatin in patients with or without ischemic heart disease. METHODS: A total of 39 patients (24 patients in the CAD group with significant coronary artery disease; 15 patients in the non-CAD group without coronary artery disease) undergoing open heart surgery were enrolled. In the CAD group, patients were classified according to good coronary collateralization (Group A; n = 11) or poor coronary collateralization (Group B; n = 13). Pericardial fluid and serum samples were obtained at the time of surgery. VEGF and endostatin were measured by enzyme-linked immunosorbent assay. RESULTS: The levels of endostatin in both serum and pericardial fluid were significantly lower in the CAD group than in the non-CAD group (130.5 +/- 37.3 ng/mL vs. 172.4 +/- 37.8 ng/mL and 119.0 +/- 25.0 ng/mL vs. 143.0 +/- 23.5 ng/mL). The concentration of serum VEGF in the CAD group (92.6 +/- 18.2 pg/mL) was significantly higher than that in the non-CAD group (75.2 +/- 22.3 pg/mL). The concentration of serum VEGF in Group A (100.1 +/- 20.7 pg/mL) was significantly higher than that in Group B (84.3 +/- 12.4 pg/mL). The levels of pericardial fluid VEGF, serum and pericardial fluid endostatin were not significantly different between Groups A and B. CONCLUSION: Patients with coronary artery disease have lower serum and pericardial fluid levels of endostatin and higher serum levels of VEGF. Serum level VEGF, but not endostatin, is associated with good or poor collateralization in patients with coronary artery disease.

Insulin-like growth factor-1 mediates stretch-induced upregulation of myostatin expression in neonatal rat cardiomyocytes.

OBJECTIVES: Myostatin, a negative regulator of muscle growth, is increased in hypertrophied and infarcted heart. However, the mechanism of regulation is not known. Mechanical stress is an important regulatory factor for cardiomyocyte growth. The aim of the study was to investigate the effect of cyclic stretch on the expression of myostatin gene in cardiomyocytes. METHODS: Neonatal Wistar rat cardiomyocytes grown on a flexible membrane base were stretched by vacuum to 20% of maximum elongation at 60 cycles/min. An in vivo model of aorta-caval shunt in adult rats was used to investigate the myostatin expression. RESULTS: Cyclic stretch significantly increased myostatin protein and mRNA expression after 6 to 18 h of stretch. Addition of the p38 mitogen-activated protein (MAP) kinase inhibitor SB203580, insulin-like growth factor-1 (IGF-1) monoclonal antibody, and p38 siRNA 30 min before stretch inhibited the induction of myostatin protein. Cyclic stretch increased, while SB203580, IGF-1, and IGF-1 receptor antibody abolished, the phosphorylated p38 protein. Gel shift assays showed significant increase of DNA-protein binding activity of myocyte enhancer factor 2 (MEF2) after stretch, and transfection with p38 siRNA abolished the DNA-protein binding activity induced by cyclic stretch. Cyclic stretch significantly increased the IGF-1 secretion from myocytes. Both conditioned media from stretched myocytes and exogenous administration of IGF-1 recombinant protein to the non-stretched myocytes increased myostatin protein expression similar to that seen after cyclic stretch. An in vivo model of aorta-caval shunt in adult rats also demonstrated the increased myostatin expression in the myocardium. CONCLUSIONS: Cyclic mechanical stretch enhances myostatin expression in cultured rat neonatal cardiomyocytes. The stretch-induced myostatin is mediated by IGF-1 at least in part through a p38 MAP kinase and MEF2 pathway.

Acetylcysteine protects against acute renal damage in patients with abnormal renal function undergoing a coronary procedure.

OBJECTIVES: We sought to evaluate the efficacy of the antioxidant acetylcysteine in limiting the nephrotoxicity after coronary procedures. BACKGROUND: The increasingly frequent use of contrast-enhanced imaging for diagnosis or intervention in patients with coronary artery disease has generated concern about the avoidance of contrast-induced nephrotoxicity (CIN). Reactive oxygen species have been shown to cause CIN. METHODS: We prospectively studied 121 patients with chronic renal insufficiency (mean [+/-SD] serum creatinine concentration 2.8 +/- 0.8 mg/dl) who underwent a coronary procedure. Patients were randomly assigned to receive either acetylcysteine (400 mg orally twice daily) and 0.45% saline intravenously, before and after injection of the contrast agent, or placebo and 0.45% saline. Serum creatinine and blood urea nitrogen were measured before, 48 h and 7 days after the coronary procedure. RESULTS: Seventeen (14%) of the 121 patients had an increase in their serum creatinine concentration of at least 0.5 mg/dl at 48 h after administration of the contrast agent: 2 (3.3%) of the 60 patients in the acetylcysteine group and 15 (24.6%) of the 61 patients in the control group (p < 0.001). In the acetylcysteine group, the mean serum creatinine concentration decreased significantly from 2.8 +/- 0.8 to 2.5 +/- 1.0 mg/dl (p < 0.01) at 48 h after injection of the contrast medium, whereas in the control group, the mean serum creatinine concentration increased significantly from 2.8 +/- 0.8 to 3.1 +/- 1.0 mg/dl (p < 0.01). CONCLUSIONS: Prophylactic oral administration of the antioxidant acetylcysteine, along with hydration, reduces the acute renal damage induced by a contrast agent in patients with chronic renal insufficiency undergoing a coronary procedure.

Induction of matrix metalloproteinases-14 and -2 by cyclical mechanical stretch is mediated by tumor necrosis factor-alpha in cultured human umbilical vein endothelial cells.

OBJECTIVE: Mechanical forces have profound effects on endothelial cells. This study was undertaken to examine the hypothesis that tumor necrosis factor-alpha (TNF-alpha) is a potential mediator of stretch-induced effects on matrix metalloproteinase (MMP). METHODS: Human umbilical vein endothelial cells (HUVECs) grown on a flexible membrane base were stretched by vacuum to 20% of maximum elongation, at 60 cycles/min. We used the TNF-alpha monoclonal antibody and c-Jun N-terminal kinase (JNK) inhibitor, SP600125, to investigate the cyclical stretch-induced expression of MMP-14 and -2 in cultured HUVECs. RESULTS: Cyclical mechanical stretch significantly increased protein synthesis and mRNA expression for MMP-14 and -2 from 2 to 24 h. The increased MMP-14 and-2 proteins after stretch were completely blocked after the addition of TNF-alpha monoclonal antibody (5 microg/ml) or SP600125 (20 microM) 30 min before stretch. By zymography, MMP-2 expression was induced by cyclical stretch and was attenuated by TNF-alpha monoclonal antibody and SP600125. Cyclical stretch increased the immunohistochemical labeling of MMP-14 and -2 and significantly increased release of TNF-alpha into the culture media from 120+/-2 to 331+/-2 pg/ml (P<0.001) after stretch for 12 h. Cyclical stretch increased and SP600125 decreased the phosphorylated JNK. Gel-shifting assay showed that DNA-protein binding activity of AP-1 increased after cyclical stretch and TNF-alpha monoclonal antibody and SP600125 abolished the binding activity induced by cyclical stretch. CONCLUSION: These findings indicate that cyclical stretch augments TNF-alpha production and MMP genes expression in HUVECs. TNF-alpha mediates the stretch-induced MMP genes expression, at least in part, through the JNK pathway.

Intramyocardial injection of naked DNA encoding HIF-1alpha/VP16 hybrid to enhance angiogenesis in an acute myocardial infarction model in the rat.

OBJECTIVES: The therapeutic utility of hypoxia-inducible factor-1 (HIF-1) transcriptional regulatory system for ischemic hindlimb has been demonstrated. It is not yet known whether this transcriptional regulatory system can be used as a therapeutic strategy to enhance collateral vessel formation in myocardial tissues, where acute hypoxia occurs due to inadequate perfusion. We aimed to test the hypothesis that exogenous administration of HIF-1alpha/VP16 could enhance collateral vessel formation in a rat acute myocardial infarction model. METHODS: Sprague-Dawley rats received ligation of the proximal left anterior descending coronary artery to induce acute myocardial infarction. Immediately after the ligation, 50 microg total plasmid DNA (control, plasmid encoding human vascular endothelial growth factor (pVEGF(165)), or pHIF-1alpha/VP16) was injected into the infarct area at three locations. RESULTS: Reverse transcription-polymerase chain reaction (RT-PCR) showed the presence of HIF-1alpha and VEGF mRNA in the myocardium, but not in other organs at days 3 and 7. The infarct size significantly decreased from 37+/-4% (control) to 24+/-2% in the VEGF-treated group and 23+/-2% in the HIF-1alpha/VP16 treated group (P<0.05). Capillary density also significantly increased from 550+/-75/mm(2) (control) to 850+/-75/mm(2) in the VEGF group and 850+/-50/mm(2) in the HIF-1alpha/VP16-treated group (P<0.01). Combined therapy with HIF-1alpha/VP16 and VEGF resulted in higher capillary density (1230+/-50/mm(2)) than treatment with either therapy alone. Regional myocardial blood flow was also higher in the treated groups than in the control. Plasma levels of VEGF were also significantly higher in the HIF-1alpha/VP16 and VEGF-treated group than in the control group. CONCLUSIONS: The HIF-1alpha/VP16 hybrid transcription factor is able to reduce infarct size and enhance neovascularization in an acute ischemic myocardium. The potency of VEGF and HIF-1alpha/VP16 hybrid as therapeutic angiogenic factors in acute hypoxic myocardium is similar.

Intramuscular vascular endothelial growth factor gene therapy in patients with chronic critical leg ischemia.

We sought to investigate the safety and efficacy of intramuscular gene therapy with vascular endothelial growth factor (VEGF) in patients with chronic critical leg ischemia.Gene transfer was performed in 24 limbs of 21 patients with rest pain, some of whom also had nonhealing ischemic ulcers (n = 16) due to occlusive peripheral arterial disease. Between 400 microg and 2000 microg of phVEGF(165) (400 microg, n = 2; 800 microg, n = 4; 1200 microg, n = 4; 1600 microg, n = 6; and 2000 microg, n = 8) was injected directly into the muscles of the ischemic limb; the same dose was injected 4 weeks later. The ratio of blood pressures at the ankle and brachial artery was measured before and after treatment. Mean (+/- SD) plasma levels of VEGF increased significantly from 26 +/- 31 pg/mL to 63 +/- 56 pg/mL (P <0.005), and the ankle-brachial index improved significantly from 0.58 +/- 0.24 to 0.72 +/- 0.28 (P <0.001). Magnetic resonance angiography showed qualitative evidence of improved distal flow in 19 limbs (79%). Ischemic ulcers healed or improved markedly in 12 limbs (75%). Rest pain was relieved or improved markedly in 20 limbs (83%). Amputation was performed in two limbs because of wound infection. Complications were limited to transient leg edema in six limbs. Intramuscular gene therapy with VEGF(165) for patients with chronic critical leg ischemia is safe, feasible, and effective.

Gastrointestinal bleeding and outcomes after percutaneous coronary intervention for ST-segment elevation myocardial infarction.

BACKGROUND: Gastrointestinal bleeding is a hemorrhagic complication after primary percutaneous coronary intervention in patients with ST-segment elevation myocardial infarction (STEMI). OBJECTIVES: To determine predictors of gastrointestinal bleeding and the impact of gastrointestinal bleeding on outcomes in STEMI patients undergoing primary percutaneous coronary intervention. METHODS AND RESULTS: Gastrointestinal bleeding occurred in 18 (3.5%) of 519 consecutive patients with STEMI undergoing primary percutaneous coronary intervention. Univariate predictors of gastrointestinal bleeding were previous gastrointestinal bleeding (33% vs 4%, P < .001), impaired renal function (89% vs 37%, P<.001), Killip class IV at presentation (61% vs 18%, P<.001), higher peak creatinine kinase level (mean [SD], 3801.6 [3280.2] vs 2721.3 [2286.6] IU/L, P=.05), and mechanical ventilator support (44% vs 12%, P<.001). Coprescription of proton-pump inhibitors did not reduce the risk of gastrointestinal bleeding (22.2% vs 13.4%, P=.22). Multivariate analysis showed an odds ratio (95% confidence interval) for gastrointestinal bleeding of 22.1 (5.6-86.89, P<.001) for previous gastrointestinal bleeding, 6.74 (1.30-34.89, P=.02) for impaired renal function, and 4.68 (1.35-16.2, P=.01) for Killip class IV at presentation. Gastrointestinal bleeding was associated with longer intensive care unit stay (mean [SD], 5.4 [6.7] vs 3.6 [3.6] days, P=.04), and higher in-hospital (44% vs 9%, P<.001) and overall (44% vs 13%, P<.001) mortality rate. CONCLUSIONS: Although rare, gastrointestinal bleeding in patients with STEMI significantly prolongs intensive care unit stay and increases mortality. Previous gastrointestinal bleeding, impaired renal function, and Killip class IV at presentation are associated with higher incidence of gastrointestinal bleeding.

Mechanism of the inhibitory effect of atorvastatin on endoglin expression induced by transforming growth factor-beta1 in cultured cardiac fibroblasts.

AIMS: Transforming growth factor-beta1 (TGF-beta1) and endoglin play a causal role in promoting cardiac fibrosis. Atorvastatin has been shown to have an inhibitory effect on cardiac fibroblasts in vitro. However, the effects of statins on TGF-beta1 and endoglin are poorly understood. We therefore sought to investigate the molecular mechanisms of atorvastatin on endoglin expression after TGF-beta1 stimulation in cardiac fibroblasts. METHODS AND RESULTS: Cultured cardiac fibroblasts were obtained from adult male Sprague-Dawley rat hearts. TGF-beta1 stimulation increased endoglin and collagen I expression and atorvastatin inhibited the induction of endoglin and collagen I by TGF-beta1. Phosphatidylinositol-3 kinase (PI-3) and Akt inhibitors (wortmannin and Akt inhibitor X) completely attenuated the endoglin protein expression induced by TGF-beta1. TGF-beta1 induced phosphorylation of PI-3 kinase and Akt, while atorvastatin and wortmannin and Akt inhibitor X inhibited the phosphorylation of PI-3 kinase and Akt induced by TGF-beta1. The gel shift and promoter activity assay showed that TGF-beta1 increased Smad3/4-binding activity and endoglin promoter activity, while wortmannin and atorvastatin inhibited the Smad3/4-binding activity and endoglin promoter activity induced by TGF-beta1. TGF-beta1 increased collagen I protein expression, while endoglin siRNA attenuated collagen I protein expression induced by TGF-beta1. Atorvastatin decreased left ventricular TGF-beta1, endoglin, and collagen I protein expression and fibrotic area in a rat model of volume overload heart failure. CONCLUSION: Atorvastatin inhibits endoglin expression through the inhibition of PI-3 kinase, Akt, and Smad3 phosphorylation, and reduced Smad3/4 binding activity and endoglin promoter activity in cardiac fibroblasts.

The causes and outcomes of inadequate implementation of existing guidelines for antiplatelet treatment in patients with acute coronary syndrome: the experience from Taiwan Acute Coronary Syndrome Descriptive Registry (T-ACCORD Registry).

BACKGROUND: Benefits of antiplatelet agents in preventing future cardiovascular events have been well established. However, the prescription pattern of antiplatelet usage in patients with acute coronary syndrome (ACS) is rarely investigated. Hence, Taiwan ACute CORonary Syndrome Descriptive Registry (T-ACCORD Registry) aimed to evaluate medical practices in Taiwan in managing ACS patients. HYPOTHESIS: The guidelines of antiplatelet treatment is not properly implanted in the management of ACS patients. METHODS: This prospective observational study was performed between April 2004 and December 2006 in 27 hospitals in Taiwan. A total of 1331 patients with unstable angina or non-ST-elevation myocardial infarction (NSTEMI) discharged from hospitals was analyzed. RESULTS: The patients with older age, lower hemoglobin levels, or previous cardiovascular ischemic diseases were less likely to receive aspirin at discharge, whereas patients with NSTEMI were less likely to receive clopidogrel at discharge. The prescription of dual antiplatelet agents declined rapidly from 61.8% at discharge to 12.6% at 12 months. The most common reason for clopidogrel discontinuation was recorded as physician's judgment. Dual antiplatelet treatment for 9 months or longer was associated with lower 1-year mortality. Percutaneous coronary intervention (PCI) was the only factor leading to dual antiplatelet therapy for at least 9 months. CONCLUSIONS: Our registry showed that underlying medical conditions may affect antiplatelet prescriptions at discharge. During the first year following an ACS episode, the prescription rate of dual antiplatelet therapy declined over time, mainly due to physician's judgment leading to the discontinuation of clopidogrel. Adherence to dual antiplatelet treatment was associated with lower total mortality at 1 year.

Acute ST-elevation myocardial infarction in young patients: 15 years of experience in a single center.

BACKGROUND: There have been few studies done regarding young patients with ST-elevation myocardial infarction (STEMI). The purpose of this study was to investigate the clinical characteristics and coronary angiographic features in young patients with STEMI. METHODS: We collected data on 849 consecutive patients with STEMI from 1992 to 2006. Baseline clinical characteristics, coronary anatomy, and outcome were compared in young (< or =45 yrs) and older patients (>45 yrs). RESULTS: Young patients presented 11.6% of all patients with STEMI. These patients were predominantly male (92.9% vs 80.3%, P < 0.001), more likely to smoke (75.8% vs 47.2%, P < 0.001), obese (48.2% vs 27.9%, P = 0.002), have higher triglyceride levels (176.9 +/- 153.8 mg/dL vs 140.7 +/- 112.7 mg/dL, P = 0.005), and lower high-density lipoprotein cholesterol (37.1 +/- 7.9 mg/dL vs 42.8 +/- 14.3 mg/dL, P = 0.005) than older patients. Also, younger patients had a shorter hospital stay (7.1 +/- 4.9 d vs 8.5 +/- 6.7 d, P = 0.04), less in-hospital morbidity (29.3% vs 39.7%, P = 0.02), and mortality (3.0% vs 12.3%, P = 0.002). Killip class III or IV could predict in-hospital morbidity and mortality in young patients. Both groups had similar rates of repeated percutaneous coronary intervention (PCI; 45.5% vs 41.5%, P = 0.23) and reinfarction (6.1% vs 3.2%, P = 0.32). Mortality rate during follow-up was significantly lower in younger patients (3.0% vs 19.6%, P < 0.001). CONCLUSION: Cigarette smoking, obesity, and dyslipidemia were the most important modifiable risk factors in young patients with STEMI. These patients had a better outcome than older patients without differences in repeated PCI and reinfarction between them. Only Killip class III or IV could predict in-hospital morbidity and mortality in young patients with STEMI.

Angiotensin II activates myostatin expression in cultured rat neonatal cardiomyocytes via p38 MAP kinase and myocyte enhance factor 2 pathway.

Angiotensin II (AngII) plays a critical role in cardiac remodeling and promotes cardiac myocyte hypertrophy. Myostatin, a negative regulator of muscle growth, is increased in hypertrophied and infarcted heart. The direct effect of AngII on cardiac myocyte myostatin expression has not been previously investigated. We hypothesized that myostatin may act as a cardiac endocrine inhibitor for AngII. AngII-induced myostatin protein expression in cultured rat neonatal cardiomyocytes was dose-dependent. AngII significantly increased myostatin protein and mRNA expression in a time-dependent manner. Addition of losartan, SB203580, or p38 siRNA 30 min before AngII stimulation significantly blocked the increase of myostatin protein by AngII. AngII significantly increased phosphorylation of p38 while SB205380 and losartan attenuated the phosphorylation of p38 induced by AngII. AngII increased, while myostatin-Mut plasmid, SB203580, losartan, and myocyte enhance factor 2 (MEF-2) antibody abolished the myostatin promoter activity. Co-stimulation with myostatin and AngII significantly inhibited the protein synthesis induced by AngII. In conclusion, AngII enhances myostatin expression in cultured rat neonatal cardiomyocytes. The AngII-induced myostatin is mediated through p38 MAP kinase and MEF-2 pathway.

Mechanical stretch enhances the expression of resistin gene in cultured cardiomyocytes via tumor necrosis factor-alpha.

The heart is a resistin target tissue and can function as an autocrine organ. We sought to investigate whether cyclic mechanical stretch could induce resistin expression in cardiomyocytes and to test whether there is a link between the stretch-induced TNF-alpha and resistin. Neonatal Wistar rat cardiomyocytes grown on a flexible membrane base were stretched by vacuum to 20% of maximum elongation at 60 cycles/min. Cyclic stretch significantly increased resistin protein and mRNA expression after 2-18 h of stretch. Addition of PD-98059, TNF-alpha antibody, TNF-alpha receptor antibody, and ERK MAP kinase small interfering RNA 30 min before stretch inhibited the induction of resistin protein. Cyclic stretch increased, whereas PD-98059 abolished, the phosphorylated ERK protein. Gel-shift assay showed a significant increase in DNA-protein binding activity of NF-kappaB after stretch, and PD-98059 abolished the DNA-protein binding activity induced by cyclic stretch. DNA binding complexes induced by cyclic stretch could be supershifted by p65 monoclonal antibody. Cyclic stretch increased resistin promoter activity, whereas PD-98059 and p65 antibody decreased resistin promoter activity. Cyclic stretch significantly increased TNF-alpha secretion from myocytes. Recombinant resistin protein and conditioned medium from stretched cardiomyocytes reduced glucose uptake in cardiomyocytes, and recombinant small interfering RNA of resistin or TNF-alpha antibody reversed glucose uptake. In conclusion, cyclic mechanical stretch enhances resistin expression in cultured rat neonatal cardiomyocytes. The stretch-induced resistin is mediated by TNF-alpha, at least in part, through ERK MAP kinase and NF-kappaB pathways. Glucose uptake in cardiomyocytes was reduced by resistin upregulation.

Predictors of long-term outcomes in patients after elective stent implantation for unprotected left main coronary artery disease.

The purpose of this study was to investigate the predictor of long-term outcomes in patients after stent implantation for unprotected left main coronary artery (LMCA) disease. Coronary stenting has recently been advocated as an alternative procedure for LMCA disease. Information on the predictors of long-term outcomes in patients after stent implantation for unprotected LMCA disease is not clear. Seventy six patients (51 men and 25 women, age 68 +/- 10 years) with medically refractory angina received coronary stenting for unprotected LMCA disease. During a follow-up period of 40 +/- 26 months, 7 patients (9%) died because of cardiovascular disease in 5 (7%) and noncardiovascular disease in 2 (3%). In the other 69 patients, 19 patients (25%) needed repeated percutaneous coronary intervention (PCI) and/or coronary artery bypass grafting (CABG). In a univariate analysis, only female sex was related to the repeated PCI and/or CABG (P = 0.04). A history of cerebral vascular attack (CVA) (P = 0.005), anemia (P = 0.03) and lower left ventricular ejection fraction (LVEF) (P = 0.008) were related to the cardiovascular mortality. A history of myocardial infarction (P = 0.03), a history of CVA (P = 0.02), anemia (P = 0.02), and lower LVEF (P = 0.002) were related to the total mortality. In a multivariate analysis, female sex (P = 0.007; odds ratio 5.29, 95% confidence interval [CI] 1.57-17.80) and young age (P = 0.025; odds ratio 3.92, 95% CI 1.19-12.98) could predict the repeated PCI and/or CABG. Only a history of CVA could predict the cardiovascular mortality (P = 0.027; odds ratio 34.18, 95% CI 1.49-783) and only lower LVEF could predict the total mortality (P = 0.027; odds ratio 13.26, 95% CI 1.34-131). Female sex and young age could predict the repeated PCI and/or CABG in patients after stent implantation for unprotected LMCA disease. Furthermore, a history of CVA could predict the cardiovascular mortality and lower LVEF could predict the total mortality.

Regulation of discoidin domain receptor 2 by cyclic mechanical stretch in cultured rat vascular smooth muscle cells.

Discoidin domain receptor 2 (DDR2) plays potential roles in the regulation of collagen turnover mediated by smooth muscle cells in atherosclerosis. How mechanical stretch affects the regulation of DDR2 in smooth muscle cells is not fully understood. We sought to investigate the cellular and molecular mechanisms of regulation of DDR2 by cyclic stretch in smooth muscle cells. Rat vascular smooth muscle cells grown on a flexible membrane base were stretched by vacuum to 20% of maximum elongation, at 60 cycles/min. Cyclic stretch significantly increased DDR2 protein and mRNA expression after stretch. Cyclic stretch also significantly increased DNA-protein binding activity of Myc-Max. Addition of SB203580, transforming growth factor-beta1 (TGF-beta1) monoclonal antibody, p38 small interfering RNA (siRNA), and c-myc siRNA 30 minutes before stretch inhibited the induction of DDR2 protein and abolished the DNA-protein binding activity induced by cyclic stretch. Cyclic stretch increased, whereas SB203580 abolished the phosphorylated p38 protein. Conditioned medium from stretched smooth muscle cells and exogenous administration of angiotensin II and TGF-beta1 recombinant proteins to the nonstretched cells increased DDR2 protein expression similar to that seen after stretch. In conclusion, cyclic mechanical stretch enhances DDR2 expression in cultured rat smooth muscle cells. The stretch-induced DDR2 is mediated by angiotensin II and TGF-beta1, at least in part, through p38 mitogen-activated protein kinase and Myc pathway.