These results demonstrate that endothelial dysfunction in ischemic heart failure occurs despite an enhanced vascular eNOS and sGC expression and can be attributed to an increase in vascular O(2)(-) production by an NADH-dependent oxidase. By inactivation of NO, O(2)(-) production appears to be an essential mechanism for the endothelial dysfunction observed in heart failure.
Mitral annular plane systolic excursion (MAPSE) has been suggested as a parameter for left ventricular (LV) function. This review describes the current clinical application and potential implications of routinely using MAPSE in patients with various cardiovascular diseases. Reduced MAPSE reflects impaired longitudinal function and thus provides complementary information to ejection fraction (EF), which represents the global result of both longitudinal and circumferential contraction. Reduced long-axis deformation results from dysfunctional or stressed longitudinal myofibres due to endo- (and potentially epi-) cardial ischaemia, fibrosis, or increased wall stress. In patients with aortic stenosis, reduced MAPSE is suggestive of subendocardial fibrosis. Moreover, reduced MAPSE could be used as a sensitive early marker of LV systolic dysfunction in hypertensive patients with normal EF, where compensatory increased circumferential deformation might mask the reduced longitudinal deformation. In addition, reduced MAPSE was associated with poor prognosis in patients with heart failure, atrial fibrillation and post-myocardial infarction as well as in patients with severe aortic stenosis undergoing aortic valve replacement. Despite of the routine use of newer and more refined echocardiographic technologies nowadays, such as strain-rate imaging, speckle-tracking imaging, and 3D echocardiography, the use of MAPSE measurement is still especially helpful to evaluate LV systolic function in case of poor sonographic windows, since good imaging quality is required for most of the modern echocardiographic techniques with the exception of tissue Doppler imaging.
We tested the effect of TGF-beta inhibition by application of a blocking antibody in mice with MI. Starting 1 week before or 5 days after coronary artery ligation mice were treated with intraperitoneal injections of an anti-TGF-beta (5 mg/kg bodyweight 1D11, Genzyme) or control antibody. Mortality over 8 weeks was significantly higher in the groups treated with the anti-TGF-beta antibody. Both, pre or post MI treatments were associated with increased left ventricular dilatation after MI as determined by serial echocardiography. In anti-TGF-beta treated mice collagen production decreased and matrix-metalloproteinase expression increased. However, the expression of TGF pro-inflammatory cytokine TNF-alpha was not altered by the treatment. Anti-TGF-beta treatment before or after coronary artery ligation increases mortality and worsens left ventricular remodeling in mice with non-reperfused MI. The detrimental effects of TGF-beta inhibition may be mediated by alterations in extracellular matrix remodeling.
Background-Identification of key molecular players in myocardial healing could lead to improved therapies, reduction of scar formation, and heart failure after myocardial infarction (MI). We hypothesized that clotting factor XIII (FXIII), a transglutaminase involved in wound healing, may play an important role in MI given prior clinical and mouse model data. Methods and Results-To determine whether a truly causative relationship existed between FXIII activity and myocardial healing, we prospectively studied myocardial repair in FXIII-deficient mice. All FXIII Ϫ/Ϫ and FXIII Ϫ/ϩ (FXIII activity Ͻ5% and 70%) mice died within 5 days after MI from left ventricular rupture. In contradistinction, FXIII Ϫ/Ϫ mice that received 5 days of intravenous FXIII replacement therapy had normal survival rates; however, cardiac MRI demonstrated worse left ventricular remodeling in these reconstituted FXIII Ϫ/Ϫ mice. Using a FXIII-sensitive molecular imaging agent, we found significantly greater FXIII activity in wild-type mice and FXIII Ϫ/Ϫ mice receiving supplemental FXIII than in FXIII Ϫ/Ϫ mice (PϽ0.05). In FXIII Ϫ/Ϫ but not in reconstituted FXIII Ϫ/Ϫ mice, histology revealed diminished neutrophil migration into the MI. Reverse transcriptase-polymerase chain reaction studies suggested that the impaired inflammatory response in FXIII Ϫ/Ϫ mice was independent of intercellular adhesion molecule and lipopolysaccharideinduced CXC chemokine, both important for cell migration. After MI, expression of matrix metalloproteinase-9 was 650% higher and collagen-1 was 53% lower in FXIII Ϫ/Ϫ mice, establishing an imbalance in extracellular matrix turnover and providing a possible mechanism for the observed cardiac rupture in the FXIII Ϫ/Ϫ mice. Conclusions-These data suggest that FXIII has an important role in murine myocardial healing after infarction.
IntroductionThe purpose of this study was to test the hypothesis that energy metabolism is impaired in residual intact myocardium of chronically infarcted rat heart, contributing to contractile dysfunction. Myocardial infarction (MI) was induced in rats by coronary artery ligation. (6), aortic stenosis (7), dilated cardiomyopathy in the Syrian hamster (8), uninephrectomy plus steroid treatment (9), or the spontaneously hypertensive rat (10). The purpose of the present work was, therefore, to define performance, oxygen consumption, and parameters of energy reserve, i.e., tissue contents of ATP and creatine phosphate (CP), creatine kinase (CK) activity and isoenzyme distribution, and phosphoryl transfer rates via CK (using 3P-magnetization transfer), in normal rat heart and in residual intact myocardium after MI. Using these measurements, we directly tested whether changes in energy metabolism can contribute to contractile dysfunction in post-MI heart. MethodsAnimals and experimental MI. Infarcts or sham operations were carried out in 12-wk-old Wistar rats, kept in a 12-h light-dark cycle. Left anterior descending coronary artery (LAD) ligation was performed by a previously described technique (1, 11). Briefly, a left thoracotomy was performed under ether anesthesia and positive pressure ventilation. The heart was rapidly exteriorized by applying gentle pressure on both sides of the thorax. The LAD was ligated between the pulmonary outflow tract and the left atrium. The heart was then replaced into the thorax, lungs were inflated by increasing positive end-expiratory pressure, and the wound was closed immediately. Sham operation was performed using an identical procedure except that the suture was passed under the coronary artery without ligation. Mortality rate of infarcted rats for the first 24 h after the operation was 40-50%. Surviving rats were kept on commercial rat chow and water ad libitum. All procedures conformed to the guiding principles of the American Physiological Society. Isolated rat heart preparation. 8 wk after LAD ligation or sham operation, rats were anesthetized by injecting 20 mg pentobarbital sodium intraperitoneally. After thoracotomy, the heart was rapidly excised and immersed in ice-cold buffer. The aorta was dissected free and mounted onto a cannula attached to a perfusion apparatus, as described previously (12). Retrograde perfusion of the heart was started in the 1092Neubauer et al.J. Clin. Invest.C) The
The study results show that quantitative mapping of perfusion and RBV may be performed noninvasively by means of MR imaging in the intact animal. The presented method allows determination of vasodilative and perfusion reserve, which reflects the in vivo regulation of coronary microcirculation for a given stimulus.
In contrast to male patients, the loss of myocardial function and the development of fibrosis do not necessarily require myocardial hypertrophy in female patients with Fabry disease. Thus, in contrast to actual recommendations, initial cardiac staging and monitoring should be based on LV hypertrophy and on replacement fibrosis in female patients with Fabry disease.
Background-Differentiation of cardiac amyloidosis (CA) from other causes of concentric left ventricular hypertrophy remains a clinical challenge, especially in patients with preserved ejection fraction at the early disease stages. Methods and Results-Consecutive hypertrophic patients with CA, isolated arterial hypertension, Fabry disease, and Friedreich ataxia (n=25 per group) were investigated; 25 healthy volunteers served as a control group. Standard echocardiography was performed, and segmental longitudinal peak systolic strain (LSsys) in the septum was assessed by 2-dimensional speckle tracking imaging. Indices of left ventricular hypertrophy and ejection fraction were similar among all patient groups. Deceleration time of early filling was significantly lower in patients with CA (147±46 milliseconds) compared with those with isolated arterial hypertension, Fabry disease, or control subjects (all P<0.0125). Septal basal LSsys (−6±2%) was significantly lower in patients with CA compared with those with isolated arterial hypertension (−14±6%), Fabry disease (−12±5%), Friedreich ataxia (−16±2%), or control subjects (−17±3%; all P<0.001), whereas septal apical LSsys was similar among all patient groups and control subjects (all P>0.05). A data-driven cutoff value for the ratio of septal apical to basal LSsys ratio >2.1 differentiated CA from other causes of left ventricular hypertrophy (sensitivity, 88%; specificity, 85%; positive predictive value, 67%; negative predictive value, 96%). The prevalence of septal apical to basal LSsys ratio >2.1 plus deceleration time of early filling <200 milliseconds was 88% in CA but 0% in all other groups. Conclusions-A systolic septal longitudinal base-to-apex strain gradient (septal apical to basal LSsys ratio >2.1), combined with a shortened diastolic deceleration time of early filling (deceleration time of early filling <200 milliseconds), aids in differentiating CA from other causes of concentric left ventricular hypertrophy. (Circ Cardiovasc Imaging. 2013;6:1066-1072.)
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.