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Query: UMLS:C0004135 (ATM)
 13,001 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vascular endothelial growth factor (VEGF), produced predominantly by endothelial cells, is involved in angiogenesis and mitogenesis. Myofibroblasts (myoFb) are phenotypically transformed fibroblast-like cells found at the site of myocardial infarction. Since myoFb play a role in tissue repair/remodeling at the site of infarction, and express endothelin and angiotensin II (AngII), it was interesting to investigate whether myoFb express VEGF and its receptors de novo, and if the expression is influenced by vasoactive peptides. Primary cultures of myoFb were isolated from 4-week-old adult rat heart infarct were used in this study. Semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR), utilizing primers designed to amplify known isoforms of VEGF revealed expression of two predominant forms, VEGF120 and VEGF164 and northern blot hybridization detected VEGF mRNA of 4.5 kb. VEGF actions are mediated via two major receptors, Flt-1 and KDR, and hence the expression of these receptors was investigated. Flt-1 and KDR expression in myoFb was detected by RT-PCR, RNA transcripts were confirmed by northern blot hybridization while western blot confirmed the presence of VEGF, Flt-1 and KDR proteins in myoFb. In this study AngII upregulated VEGF and Flt-1 expression in myoFb, but not KDR; this was mediated predominantly by AT1-receptor. We report for the first time that cardiac myoFb, isolated from the site of infarction express VEGF, its receptors, Flt-1 and KDR, with modulation of VEGF and Flt-1 expression by AngII. Thus, VEGF may contribute to tissue remodeling and angiogenesis at the site of infarction in an autocrine manner.
J Mol Cell Cardiol 2003 Mar
PMID:Cardiac myofibroblasts: a novel source of vascular endothelial growth factor (VEGF) and its receptors Flt-1 and KDR. 1267 42

Chronic systemic hypertension leads to structural and functional changes in the left ventricular myocardium through external and internal stimuli, altering the molecular structure of some peptides that influence hypertrophy and remodeling development. Genetic information evokes different responses in the cardiac myocyte, altering its morphology, metabolism, protein synthesis and the bioavailability of some hormonal receptors, promoting compensatory hypertrophy or apoptosis. In response to hemodynamic stress, the myocardial cell sensitizes and liberates angiotensin II (ATII) in an endogenous fashion and makes AT1 receptors to join this hormone tightly, perpetuating its deleterious effects. AT1 selective blockade prevent molecular and physiological damage lowering ATII bioavailability, down-regulating its production.
Arch Cardiol Mex
PMID:[Hypertrophy and ventricular remodeling in systemic arterial hypertension: role of AT1 receptors]. 1296 67

The pathophysiologic mechanisms of myocardial remodeling in heart failure (HF) remain poorly understood. Using differential mRNA display of myocardial tissue from rats with ischemic HF vs. controls we identified robust myocardial induction of the mRNA encoding connective tissue growth factor (CTGF). The aim of this study was to investigate the sites of synthesis and the mechanisms of induction of CTGF in failing myocardial tissue. The study demonstrates that myocardial expression of CTGF mRNA and protein is substantially elevated in non-ischemic tissue from both the left and the right ventricles of rats with experimentally induced myocardial infarction (MI). The induction of myocardial CTGF mRNA was shown to transcend from early post-infarction HF to chronic HF. In situ hybridization and immunohistochemical analysis of myocardial tissue sections demonstrated expression of CTGF confined to fibroblasts and endothelial cells of non-ischemic myocardial tissue. In subsequent experiments rats subjected to MI were randomized to treatment with the AT1 angiotensin receptor antagonist losartan (12.5 mg/kg b.i.d. per os) or vehicle. Losartan attenuated ventricular hypertrophy, improved hemodynamics, and prevented the induction of myocardial CTGF mRNA observed in rats post-MI. To provide the cellular basis of Ang II-stimulated CTGF mRNA expression, primary cultures of rat myocardial fibroblasts were stimulated with Ang II (10(-7) M). Real-time reverse transcription-polymerase chain reaction and western blot analysis demonstrate that Ang II induces rapid, AT1 receptor-mediated elevations of CTGF mRNA and protein in rat cardiac fibroblasts. Furthermore, CTGF was shown to stimulate fibroblast proliferation in vitro. In conclusion, this study demonstrates that CTGF is a myocardial effector of Ang II-induced myocardial remodeling in HF mediated via AT1 receptors situated on cardiac fibroblasts.
J Mol Cell Cardiol 2004 Mar
PMID:Connective tissue growth factor--a novel mediator of angiotensin II-stimulated cardiac fibroblast activation in heart failure in rats. 1501 Feb 78

Autocrine stimulation and paracrine interaction between coronary smooth muscle cells (cSMC) and endothelial cells (EC) act as regulators of the vascular angiogenesis. Basic fibroblast growth factor (bFGF), its receptor FGF-R1, and coreceptor heparansulfate proteoglycan (HSPG) are important components involved in this angiogenic process. We investigated the influence of angiotensin (Ang) II on this trimolecular bFGF complex, the underlying signaling and the proliferative process in human cSMC. Ang II induces an AT1 receptor-dependent expression of bFGF and also upregulates the FGF-R1 and HSPG expression which is suppressed by losartan, the AT1 receptor blocker. AT1 receptor signaling which is characterized by phosphorylation of p42-mitogen-activated protein kinase (MAPK) is involved in Ang II-induced bFGF, FGF-R1 and HSPG upregulation and DNA synthesis in human cSMC. In contrast, inhibition of the AT2 receptor by PD123,319 has no influence on these Ang II-stimulated and via the MAPK cascade-mediated proangiogenic effects. Finally, our data show that the Ang II-induced DNA synthesis in cSMC is mediated via the bFGF expression. In conclusion, our results suggest that the Ang II-induced angiogenic effects in the vessel wall are supported by the AT1 receptor-stimulated and MAPK pathway-mediated upregulation of the autocrine/paracrine trimolecular bFGF complex in cSMC.
Basic Res Cardiol 2004 Jul
PMID:Angiotensin AT1 receptor upregulates expression of basic fibroblast growth factor, basic fibroblast growth factor receptor and coreceptor in human coronary smooth muscle cells. 1522 45

It would appear that a significant number of cardiologists are unaware that skin injuries ranging from erythema to telangiectasia or even dermal necrosis can be caused by the procedures they perform. Conditions that have been reported to be associated with radiation-induced skin injuries include: the high values of the exposure factors required with thick patients; prolonged or multiple procedures; elevated radiosensitivity of some patients (ataxia telangiectasia); connective tissue disease and diabetes mellitus. The total number of reported severe injuries worldwide so far is 100-200, or over 200 when all degrees of skin injuries are included, but the real number may be substantially larger since initial symptoms often appear only weeks after the procedure and the cardiologist may not be notified, unless a procedure for systematic follow up is in place. Besides skin injuries, patients-more so, the younger ones-incur a risk of radiation-induced cancer at some stage in the future. Experience shows that, with awareness of radiation safety aspects, proper equipment performance, the use of proper techniques, and the monitoring of patient doses, severe skin injuries should not occur in patients undergoing 5-10 PTCA-s. However, for those patients whose radiation doses approach the thresholds for radiation injuries a systematic follow up is required. These issues are addressed here.
Int J Cardiol 2006 May 10
PMID:Radiation effects in fluoroscopically guided cardiac interventions--keeping them under control. 1603 1

Angiostensin II (Ang II) regulates the migration and proliferation of vascular smooth muscle cells. Recent studies indicate that intermediate-conductance Ca2+ -activated K+ (IKca) channels have an important role in cell migration and proliferation. It is not known, however, whether the action of Ang II is linked to IKca channel regulation. Here, we investigated the modulation of IKca channels by Ang II in artery smooth muscle cells. Functional IKca channel expression in cultured embryonic rat aorta smooth muscle (A10) cells was studied using the patch-clamp technique. These cells predominantly express IKca channels. In contrast, large-conductance Ca2+ -activated K+ (BKca) currents were rarely observed in excised patches. Ang II increased the IKca current in a contration-dependent manner. Losartan (1.0 microM), an AT1 selective antagonist, abolished the activation of IKca channels by Ang II. Pretreatment with 100 microM myristoylated protein kinase C inhibitor peptide 20-28 or 10 microM GF109203X completely abolished the AngII-induced activation of IKca currents, whereas the action of Ang II was not prevented in the presence of 100 microM Rp-cyclic 3', 5'-hydrogen phosphotiate adenosine triethylammonium, a protein kinase A inhibitor, or 1.0 microM KT-5823, a protein kinase G inhibitor. A membrane permeant analogue of diacylglycerol 1, 2-dioctanoyl-sn-glycerol (10 microM) induced the activation of IKca currents. These data suggest that Ang II activates IKca channels through the activation of protein kinase C, and the AT1 receptor is involved in the regulation of these channels.
J Mol Cell Cardiol 2006 Dec
PMID:Angiotensin II activates intermediate-conductance Ca2+ -activated K+ channels in arterial smooth muscle cells. 1691 91

The treatment and management of patients with arterial hypertension depends on the global cardiovascular risk of the individual patient. Thus, additional cardiovascular risk factors, the presence of target organ damage, cardiovascular or renal disease determine not only the initiation of therapy but also the choice of drug(s). Drug treatment is usually started with one compound, which is selected from 5 drug classes recommended for first-line therapy including ACE-inhibitors, AT1-antagonists, betablockers, calcium channel blockers, and diuretics. Depending on risk and additional disease individual target blood pressures are 140/90, 130/80 or 125/75 mmHg, respectively. If blood pressures at baseline exceeds target values more than 20/10 mmHg treatment may be started with initial or early combination therapy of two drugs. Overall, approximately two-thirds of patients require treatment with at least two drugs to achieve target blood pressure values.
Clin Res Cardiol 2006
PMID:[Therapy of hypertension]. 1701 83

Cardiotrophin-1 (CT-1) produces longitudinal elongation of neonatal cardiomyocytes, but its effects in adult cardiomyocytes are not known. Recent observations indicate that CT-1 may be involved in pressure overload left ventricular hypertrophy (LVH). We investigated whether the hypertrophic effects of CT-1 are different in cardiomyocytes isolated from adult normotensive and spontaneously hypertensive rats (SHR). Hypertrophy was evaluated by planimetry and confocal microscopy, contractile proteins were quantified by Western blotting and real-time RT-PCR, and intracellular pathways were analyzed with specific chemical inhibitors. CT-1 increased c-fos and ANP expression (p<0.01) and cell area (p<0.01) in cardiomyocytes from both rat strains. In Wistar cells, CT-1 augmented cell length (p<0.01) but did not modify either the transverse diameter or cell depth. In SHR cells, CT-1 increased cell length (p<0.05), cell width (p<0.01) and cell depth, augmented the expression of myosin light chain-2v (MLC-2v) and skeletal alpha-actin (p<0.01) and enhanced MLC-2v phosphorylation (p<0.01). The blockade of gp130 or LIFR abolished CT-1-induced growth in the two cell types. All distinct effects observed in cardiomyocytes from SHR were mediated by STAT3. Baseline angiotensinogen expression was higher in SHR cells, and CT-1 induced a 1.7-fold and 3.2-fold increase of angiotensinogen mRNA in cardiomyocytes from Wistar rats and SHR respectively. In addition, AT1 blockade inhibited the specific effects of CT-1 in SHR cells. Finally, ex vivo determinations revealed that adult SHR exhibited enhanced myocardial CT-1 (mRNA and protein, p<0.01), increased cell width (p<0.01) and concentric LVH compared with pre-hypertensive SHR. These findings reveal a specific cell-broadening effect of CT-1 in cardiomyocytes from adult SHR and suggest that the hypertensive phenotype of these cells may influence the hypertrophic effects of CT-1, probably by means of an exaggerated induction of angiotensinogen expression. We suggest that CT-1 might facilitate LVH in genetic hypertension through a cross-talk with the renin-angiotensin system.
J Mol Cell Cardiol 2006 Nov
PMID:Differential hypertrophic effects of cardiotrophin-1 on adult cardiomyocytes from normotensive and spontaneously hypertensive rats. 1701 64

Elevated activities of the sympathetic nerve and renin-angiotensin systems are common features of heart failure. This study was designed to investigate the roles of the AT1 receptor in cardiac hypertrophy and oxidative stress during excessive beta-adrenoceptor stimulation using an AT1 receptor antagonist (ARB) and AT1a receptor-deficient (AT1aR(-/-)) mice. Isoproterenol (ISO) was given to C57BL mice with or without ARB (olmesartan) treatment and to AT1aR(-/-) mice by a subcutaneously implanted osmotic mini-pump for 11 days at a rate of 15 mg/kg/day. Chronic ISO infusion to C57BL mice caused concentric cardiac hypertrophy (sham; 4.1+/-0.1, ISO; 5.2+/-0.2 mg/g heart to body weight ratio), accompanied by enhancement of cardiac collagen accumulation, lipid peroxidation, superoxide generation and NADPH oxidase activity. The AT1a and beta-1,2 receptor mRNA expressions were down-regulated in the heart of ISO-infused mice. Olmesartan markedly suppressed cardiac mass enlargement as well as increases of oxidative indicators without any effects on heart rate. Olmesartan did not affect the cardiac angiotensin and beta-adrenergic receptor mRNA expression patterns. The AT1a receptor contribution to ISO-induced cardiac hypertrophy was reproduced in AT1aR(-/-) mice. These data suggest that the AT1 receptor plays a crucial role in the development of cardiac hypertrophy and oxidative stress under excessive beta-adrenergic stimulation, and that ARB treatment is beneficial for sympatho-excitatory cardiac hypertrophy and failure in mice.
J Mol Cell Cardiol 2007 Apr
PMID:Role of AT1 receptor in isoproterenol-induced cardiac hypertrophy and oxidative stress in mice. 1735 36

Microalbuminuria (MA), conventionally defined as a urinary albumin excretion (UAE) of 30-300 mg/day, is recognised as a marker of endothelial dysfunction. Furthermore, it represents an established risk factor for cardiovascular morbidity and mortality and for end-stage renal disease in individuals with an adverse cardiovascular risk profile. It is common in the general population, particularly in patients with diabetes mellitus or arterial hypertension. There is growing evidence from prospective observational trials that UAE levels well below the current MA threshold ("lowgrade MA") are also associated with an increased risk of incident cardiovascular disease and allcause mortality. Even in apparently healthy individuals (without diabetes or hypertension), such an association has been shown. As albuminuria screening assays that are reliable even in the lower ranges are commercially available, there may be an important clinical role for MA in disease screening, comparable to the role of blood pressure and lipid screening. MA is modifiable, and the inhibition of the renin-angiotensin system by ACE inhibitors and AT1 receptor antagonists has been shown to result in a lower incidence of cardiovascular events.
Clin Res Cardiol 2007 May
PMID:Low-grade albuminuria and cardiovascular risk : what is the evidence? 1745 40


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