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delivery attenuates myocardial infarction and apoptosis after ischemia and reperfusion. Am J Physiol Heart Circ Physiol 285: H1506-H1514, 2003. First published June 12, 2003 10.1152/ ajpheart.00270.2003 has been shown to protect against cardiac remodeling. In this study, we investigated the potential role of AM in myocardial ischemiareperfusion (I/R) injury through adenovirus-mediated gene delivery. One week after AM gene delivery, rats were subjected to 30-min coronary occlusion, followed by 2-h reperfusion. AM gene transfer significantly reduced the ratio of infarct size to ischemic area at risk and the occurrence of sustained ventricular fibrillation compared with control rats. AM gene delivery also attenuated apoptosis, assessed by both terminal deoxynucleotidyl transferase-mediated dUTP nickend labeling assay and DNA laddering. The effect of AM gene transfer on infarct size, arrhythmia, and apoptosis was abolished by an AM antagonist, calcitonin gene-related peptide ]. Expression of human AM significantly increased cardiac cGMP levels and reduced superoxide production, superoxide density, NAD(P)H oxidase activity, p38 MAPK activation, and Bax levels. Moreover, AM increased Akt and Bad phosphorylation and Bcl-2 levels, but decreased caspase-3 activation. These results indicate that AM protects against myocardial infarction, arrhythmia, and apoptosis in I/R injury via suppression of oxidative stress-induced Bax and p38 MAPK phosphorylation and activation of the AktBad-Bcl-2 signaling pathway. Successful application of this technology may have a protective effect in coronary artery diseases.superoxide; Akt; Bax; p38 MAPK ADRENOMEDULLIN (AM) was first isolated from human pheochromocytoma tissue in 1993 (20) and has been identified in tissues relevant to cardiovascular and renal function, such as the adrenal medulla, kidney, heart, aorta, lung, and brain (14,35). AM is a potent vasodilator as intravenous administration of the AM peptide produced a hypotensive effect along with a marked reduction of total peripheral resistance in animals and humans (7,19). In addition to influencing the contractile state of blood vessels, AM also inhibits protein and DNA synthesis in cultured cardiac myocytes and fibroblasts, which is mediated via a cAMPdependent pathway (16). Transgenic mice overexpressing the AM gene under the control of the preproendothelin-1 promoter have reduced mean blood pressure (30). Nitric oxide (NO) synthase (NOS) inhibition normalizes blood pressure in these mice, indicating a role of NO/cGMP in mediating the AM effect. Embryos of AM-deficient mice die at midgestation with cardiovascular abnormalities, including overdeveloped ventricular trabeculae and underdeveloped arterial walls (3). Increased AM levels have been reported in the pathophysiology of cardiac diseases such as hypertension, cardiac hypertrophy, and heart failure (15, 17). Elevated AM production could be a biological attempt to compensate for cardiac and renal damage. These findings suggest important roles of AM in the development and f...

Insulin resistance, the most important factor in metabolic syndrome X, has been considered to raise blood pressure. Recently it was reported that insulin resistance was related to an elevated plasma level of leptin, which is an adipocyte-specific ob gene product and which plays a role in food intake suppression, thermogenesis, and energy expenditure through the activation of the hypothalamus. However there are no reports that deal with the relationship of insulin resistance to plasma leptin and blood pressure. To evaluate the role of leptin in essential hypertensives, two groups of subjects who were carefully matched for body mass index (BMI) were studied; 22 normotensives (NT, age: 46.5 +/- 2.6 years, BMI: 23.9 +/- 0.4 kg/m2, male/female: 14/8) and 45 mild-to-moderate essential hypertensives (EHT, age: 51.9 +/- 2.0 years, BMI: 24.5 +/- 0.4 kg/m2, male/female: 21/24). We applied the euglycemic hyperinsulinemic glucose clamp technique to all subjects and insulin sensitivity was evaluated as the M value. EHT showed a significantly lower M value (160.2 +/- 7.4 v 184.3 +/- 7.3 mg/m2/min, P < .05) and higher basal plasma immunoreactive leptin level (7.6 +/- 0.8 v 5.0 +/- 0.8 ng/mL, P < .05) than NT, despite the fact that there was no significant difference between NT and EHT in age, gender, or BMI. The relationship between mean blood pressure and leptin showed a significant positive correlation in all of the subjects (r = 0.31, P < .05), suggesting that leptin may be related to a pathophysiology of essential hypertension.

Objective-Endothelium-derived NO has been shown to mediate the mitogenic effect of vascular endothelial growth factor on cultured microvascular endothelium. To evaluate the role of endothelial NO synthase (eNOS) in angiogenesis in the ischemic hindlimb, we engineered an adenovirus containing human eNOS cDNA. Methods and Results-After gene transfer, expression of eNOS in cultured cells was detected by increased intracellular cGMP and nitrate/nitrite levels and NO synthase activity. Adenovirus containing either the eNOS or luciferase gene was injected into the adductor muscle of rat hindlimbs immediately after femoral artery removal. Human eNOS protein was detected throughout the course of the experiment by immunostaining. Significant increases in blood perfusion were monitored by laser Doppler imaging from 2 to 4 weeks after gene delivery in the ischemic hindlimb of rats receiving eNOS compared with control rats receiving the reporter gene. An increase in regional blood flow was also detected after eNOS gene transfer by a fluorescent microsphere assay. eNOS gene delivery in the ischemic hindlimb resulted in significant increases in intracellular cGMP levels and in capillary density identified by anti-CD-31 immunostaining. Angiogenesis was further confirmed in mice after eNOS gene transfer by increased hemoglobin content in Matrigel implants. Conclusions-Taken

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Abstract-In this study, we used the somatic gene delivery approach to explore the role of the kallikrein-kinin system (KKS) in cardiac remodeling and apoptosis after myocardial infarction (MI). Rats were subjected to coronary artery ligation to induce MI, and adenovirus carrying the human tissue kallikrein or luciferase gene was injected into the tail vein at 1 week after surgery. Cardiac output gradually decreased from 2 to 6 weeks after MI, whereas delivery of the kallikrein gene prevented this decrease. Cardiac responses to dobutamine-induced stress were improved in rats receiving kallikrein gene as compared with rats receiving control virus at 6 weeks after MI. Kallikrein significantly improved cardiac remodeling by decreasing collagen density, cardiomyocyte size, and left ventricular internal perimeter and increasing capillary density in the heart at 6 weeks after MI. Kallikrein gene transfer attenuated myocardial apoptosis, which was positively correlated with remodeling parameters in the heart at 2 weeks after MI. Endothelial dysfunction, characterized by increased vascular resistance, decreased left ventricular blood flow, and decreased cardiac nitric oxide levels, existed in remodeled hearts at 2 weeks after MI, whereas kallikrein gene transfer improved these parameters. Kallikrein gene delivery improved cell survival parameters as shown by increased phospho-Akt and reduced caspase-3 activation at 2 weeks after MI. This study indicates that the kallikrein-kinin system plays an important role in preventing the progression of heart failure by attenuating cardiac hypertrophy and fibrosis, improving endothelial function, and inhibiting myocardial apoptosis through the Akt-mediated signaling pathway. Key Words: myocardial infarction Ⅲ remodeling Ⅲ kallikrein-kinin systems Ⅲ genes Ⅲ apoptosis A ngiotensin-converting enzyme inhibition was first shown to improve the survival of coronary ligation-induced myocardial infarction (MI) in a rat model. 1 Treatment of the ACE inhibitor enalapril increased survival in rats with congestive heart failure. 2 Subsequent studies have confirmed beneficial effects of ACE inhibitors in reduction of morbidity and mortality rates and improvement in the quality of life in patients. 3,4 Therefore, treatment based on ACE inhibition has become an established therapy for patients with chronic heart failure (CHF), systolic left ventricular (LV) dysfunction, and MI. [5][6][7][8] The effects of ACE inhibitors on CHF are mostly attributed to the blockade of angiotensin II (Ang II) production, which induces cardiomyocyte hypertrophy after MI or heart failure. 9 It has been shown that Ang II stimulates collagen synthesis in cultured cardiac fibroblasts 10 and induces apoptosis in cardiomyocytes and endothelial cells. [11][12][13] Collectively, these observations support a role of Ang II in promoting the progression of cardiac remodeling and suppressing cardiac function. Since ACE is the same enzyme as kininase II, a kinin-degrading enzyme, inhibition of ACE not only results in reduced Ang I...

We investigated the role of the kallikrein-kinin system in cardiac function and glucose utilization in the streptozotocin (STZ)-induced diabetic rat model using a gene transfer approach. Adenovirus harboring the human tissue kallikrein gene was administered to rats by intravenous injection at 1 week after STZ treatment. Human kallikrein transgene expression was detected in the serum and urine of STZ-induced diabetic rats after gene transfer. Kallikrein gene delivery significantly reduced blood glucose levels and cardiac glycogen accumulation in STZ-induced diabetic rats. Kallikrein gene transfer also significantly attenuated elevated plasma triglyceride and cholesterol levels, food and water intake, and loss of body weight gain, epididymal fat pad, and gastrocnemius muscle weight in STZ-induced diabetic rats. However, these effects were blocked by icatibant, a kinin B2 receptor antagonist. Cardiac function was significantly improved after kallikrein gene transfer as evidenced by increased cardiac output and ؎⌬P/⌬t T issue kallikrein specifically processes low-molecular weight kininogen to produce potent vasoactive kinin peptides (1). Intact kinin binds to the bradykinin B2 receptor and transduces signals through nitric oxide (NO)-cGMP and prostacyclincAMP pathways, thereby modulating a broad spectrum of cellular functions (2). The B2 receptor can be blocked by the specific B2 receptor antagonist icatibant (also known as HOE140) (3). Previous reports have shown that the kallikrein-kinin system (KKS) components are locally expressed in the heart (4), and streptozotocin (STZ)-induced diabetes results in a decrease of active cardiac tissue kallikrein levels (5,6), resulting in increased thickness of the left ventricle wall and cardiac hypertrophy (7). The STZ animal model develops characteristic symptoms of diabetes such as hyperglycemia, hyperlipidemia, and increased water and food intake without body weight gain. In addition, STZ diabetes also induces key symptoms including increased glycogen storage in the myocardium, depressed ventricular performance, and cardiac hypertrophy (8). Our recent studies using gene transfer approaches have demonstrated that the KKS improves cardiac function in animal models of myocardial ischemia, chronic heart failure, and cardiac hypertrophy (9 -11). In addition, transgenic rats overexpressing the human tissue kallikrein gene resulted in reduction of isoproterenol-induced cardiac hypertrophy and fibrosis, and these protective effects were abolished by icatibant (12). These findings indicate a potential protective role of the KKS in diabetic cardiomyopathy.STZ-induced diabetes results in hyperglycemia and hyperlipidemia, and without insulin treatment, animals have poor control over glucose and circulating lipid levels. Previous studies have shown that the KKS is involved in glucose management by stimulating GLUT4 translocation (13), improving insulin stimulation of GLUT4 (14), and preventing dephosphorylation of insulin receptor substrate-1 (15). Whether the KKS plays a role in impro...