989 resultados para Ventricular Dysfunction Right
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Objectives: The purpose of this study was to investigate the levels of electromyographic (EMG) activation and maximal molar bite force before and after a 3-month acupuncture therapy in individuals with temporomandibular disorder (Helkimo Index) from a pool of subjects attending the Special Care Course of the Ribeirao Preto Dental School, Sao Paulo University, Brazil. Design: All 17 patients, aged between 37 and 50 years (44.2 +/- 4.84 years), with an average weight of 71 +/- 9.45 kg and height of 1.64 +/- 0.07 m, were clinically examined with regard to pain and dysfunctions of the masticatory system. The temporomandibular acupuncture points of needling were IG4, E6, E7, B2, VB14, VB20, ID18, ID19, F3, E36, VB34, E44, R3, and HN3. EMG measures were acquired before and after the treatment using a MyoSystem-BR1 electromyographer. The data collected at rest, protrusion, left and right laterality, and clenching were normalized by maximum voluntary contraction. Maximal bite force in right and left molar regions were registered using a dynamometer with a capacity of up to 1000 N, adapted for oral conditions. The highest value out of three recordings was considered to be the individual's maximal bite force. The results were statistically analyzed using the paired t test (SPSS version 15.0) during the comparison before and after treatment. Results: We found decreased EMG activity at rest, protrusion, left and right laterality, and clenching; as well as increased values of maximal bite force after acupuncture treatment. Conclusions: Acupuncture promoted alterations in the EMG activity of masticatory muscles, increased maximal molar bite force, and led to remission of the subjects' painful symptomatology.
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Preeclampsia, a pregnancy-specific syndrome characterized by hypertension, proteinuria and edema, is a major cause of fetal and maternal morbidity and mortality especially in developing countries. Bj-PRO-10c, a proline-rich peptide isolated from Bothrops jararaca venom, has been attributed with potent anti-hypertensive effects. Recently, we have shown that Bj-PRO-10c-induced anti-hypertensive actions involved NO production in spontaneous hypertensive rats. Using in vitro studies we now show that Bj-PRO-10c was able to increase NO production in human umbilical vein endothelial cells from hypertensive pregnant women (HUVEC-PE) to levels observed in HUVEC of normotensive women. Moreover, in the presence of the peptide, eNOS expression as well as argininosuccinate synthase activity, the key rate-limiting enzyme of the citrulline-NO cycle, were enhanced. In addition, excessive superoxide production due to NO deficiency, one of the major deleterious effects of the disease, was inhibited by Bj-PRO-10c. Bj-PRO-10c induced intracellular calcium fluxes in both, HUVEC-PE and HUVEC, which, however, led to activation of eNOS expression only in HUVEC-PE. Since Bj-PRO-10c promoted biological effects in HUVEC from patients suffering from the disorder and not in normotensive pregnant women, we hypothesize that Bj-PRO-10c induces its anti-hypertensive effect in mothers with preeclampsia. Such properties may initiate the development of novel therapeutics for treating preeclampsia.
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Mitochondria and NADPH oxidase activation are concomitantly involved in pathogenesis of many vascular diseases. However, possible cross-talk between those ROS-generating systems is unclear. We induced mild mitochondrial dysfunction due to mitochondrial DNA damage after 24 h incubation of rabbit aortic smooth muscle (VSMC) with 250 ng/mL ethidium bromide (EtBr). VSMC remained viable and had 29% less oxygen consumption, 16% greater baseline hydrogen peroxide, and unchanged glutathione levels. Serum-stimulated proliferation was unaltered at 24 h. Although PCR amplification of several mtDNA sequences was preserved, D-Loop mtDNA region showed distinct amplification of shorter products after EtBr. Such evidence for DNA damage was further enhanced after angiotensin-II (AngII) incubation. Remarkably, the normally observed increase in VSMC membrane fraction NADPH oxidase activity after AngII was completely abrogated after EtBr, together with failure to upregulate Nox1 mRNA expression. Conversely, basal Nox4 mRNA expression increased 1.6-fold, while being unresponsive to AngII. Similar loss in AngII redox response occurred after 24 h antimycin-A incubation. Enhanced Nox4 expression was unassociated with endoplasmic reticulum stress markers. Protein disulfide isomerase, an NADPH oxidase regulator, exhibited increased expression and inverted pattern of migration to membrane fraction after EtBr. These results unravel functionally relevant cross-talk between mitochondria and NADPH oxidase, which markedly affects redox responses to AngII. Antioxid Redox Signal 11, 1265-1278.
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Previous studies show that exercise training and caloric restriction improve cardiac function in obesity. However, the molecular mechanisms underlying this effect on cardiac function remain unknown. Thus, we studied the effect of exercise training and/or caloric restriction on cardiac function and Ca(2+) handling protein expression in obese rats. To accomplish this goal, male rats fed with a high-fat and sucrose diet for 25 weeks were randomly assigned into 4 groups: high-fat and sucrose diet, high-fat and sucrose diet and exercise training, caloric restriction, and exercise training and caloric restriction. An additional lean group was studied. The study was conducted for 10 weeks. Cardiac function was evaluated by echocardiography and Ca(2+) handling protein expression by Western blotting. Our results showed that visceral fat mass, circulating leptin, epinephrine, and norepinephrine levels were higher in rats on the high-fat and sucrose diet compared with the lean rats. Cardiac nitrate levels, reduced/oxidized glutathione, left ventricular fractional shortening, and protein expression of phosphorylated Ser(2808)-ryanodine receptor and Thr(17-)phospholamban were lower in rats on the high-fat and sucrose diet compared with lean rats. Exercise training and/or caloric restriction prevented increases in visceral fat mass, circulating leptin, epinephrine, and norepinephrine levels and prevented reduction in cardiac nitrate levels and reduced: oxidized glutathione ratio. Exercise training and/or caloric restriction prevented reduction in left ventricular fractional shortening and in phosphorylation of the Ser(2808)-ryanodine receptor and Thr(17)-phospholamban. These findings show that exercise training and/or caloric restriction prevent cardiac dysfunction in high-fat and sucrose diet rats, which seems to be attributed to decreased circulating neurohormone levels. In addition, this nonpharmacological paradigm prevents a reduction in the Ser(2808)-ryanodine receptor and Thr(17-)phospholamban phosphorylation and redox status. (Hypertension. 2010;56:629-635.)
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Bueno CR Jr, Ferreira JC, Pereira MG, Bacurau AV, Brum PC. Aerobic exercise training improves skeletal muscle function and Ca(2+) handling-related protein expression in sympathetic hyperactivity-induced heart failure. J Appl Physiol 109: 702-709, 2010. First published July 1, 2010; doi: 10.1152/japplphysiol.00281.2010.-The cellular mechanisms of positive effects associated with aerobic exercise training on overall intrinsic skeletal muscle changes in heart failure (HF) remain unclear. We investigated potential Ca(2+) abnormalities in skeletal muscles comprising different fiber compositions and investigated whether aerobic exercise training would improve muscle function in a genetic model of sympathetic hyperactivity-induced HF. A cohort of male 5-mo-old wild-type (WT) and congenic alpha(2A)/alpha(2C) adrenoceptor knockout (ARKO) mice in a C57BL/6J genetic background were randomly assigned into untrained and trained groups. Exercise training consisted of a 8-wk running session of 60 min, 5 days/wk (from 5 to 7 mo of age). After completion of the exercise training protocol, exercise tolerance was determined by graded treadmill exercise test, muscle function test by Rotarod, ambulation and resistance to inclination tests, cardiac function by echocardiography, and Ca(2+) handling-related protein expression by Western blot. alpha(2A)/alpha(2C)ARKO mice displayed decreased ventricular function, exercise intolerance, and muscle weakness paralleled by decreased expression of sarcoplasmic Ca(2+) release-related proteins [alpha(1)-, alpha(2)-, and beta(1)-subunits of dihydropyridine receptor (DHPR) and ryanodine receptor (RyR)] and Ca(2+) reuptake-related proteins [sarco(endo) plasmic reticulum Ca(2+)-ATPase (SERCA) 1/2 and Na(+)/Ca(2+) exchanger (NCX)] in soleus and plantaris. Aerobic exercise training significantly improved exercise tolerance and muscle function and reestablished the expression of proteins involved in sarcoplasmic Ca(2+) handling toward WT levels. We provide evidence that Ca(2+) handling-related protein expression is decreased in this HF model and that exercise training improves skeletal muscle function associated with changes in the net balance of skeletal muscle Ca(2+) handling proteins.
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Overwhelming evidence supports the importance of the sympathetic nervous system in heart failure. In contrast, much less is known about the role of failing cholinergic neurotransmission in cardiac disease. By using a unique genetically modified mouse line with reduced expression of the vesicular acetylcholine transporter (VAChT) and consequently decreased release of acetylcholine, we investigated the consequences of altered cholinergic tone for cardiac function. M-mode echocardiography, hemodynamic experiments, analysis of isolated perfused hearts, and measurements of cardiomyocyte contraction indicated that VAChT mutant mice have decreased left ventricle function associated with altered calcium handling. Gene expression was analyzed by quantitative reverse transcriptase PCR and Western blotting, and the results indicated that VAChT mutant mice have profound cardiac remodeling and reactivation of the fetal gene program. This phenotype was attributable to reduced cholinergic tone, since administration of the cholinesterase inhibitor pyridostigmine for 2 weeks reversed the cardiac phenotype in mutant mice. Our findings provide direct evidence that decreased cholinergic neurotransmission and underlying autonomic imbalance cause plastic alterations that contribute to heart dysfunction.
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Cardiomyocyte hypertrophy occurs in response to a variety of physiological and pathological stimuli. While pathological hypertrophy in heart failure is usually coupled with depressed contractile function, physiological hypertrophy associates with increased contractility. In the present study, we explored whether 8 weeks of moderate intensity exercise training would lead to a cardiac anti-remodelling effect in an experimental model of heart failure associated with a deactivation of a pathological (calcineurin/NFAT, CaMKII/HDAC) or activation of a physiological (Akt-mTOR) hypertrophy signalling pathway. The cardiac dysfunction, exercise intolerance, left ventricle dilatation, increased heart weight and cardiomyocyte hypertrophy from mice lacking alpha(2A) and alpha(2C) adrenoceptors (alpha(2A)/alpha(2C)ARKO mice) were associated with sympathetic hyperactivity induced heart failure. The relative contribution of Ca(2+)-calmodulin high-affinity (calcineurin/NFAT) and low-affinity (CaMKII/HDAC) targets to pathological hypertrophy of alpha(2A)/alpha(2C)ARKO mice was verified. While nuclear calcineurin B, NFATc3 and GATA-4 translocation were significantly increased in alpha(2A)/alpha(2C)ARKO mice, no changes were observed in CaMKII/HDAC activation. As expected, cyclosporine treatment decreased nuclear translocation of calcineurin/NFAT in alpha(2A)/alpha(2C)ARKO mice, which was associated with improved ventricular function and a pronounced anti-remodelling effect. The Akt/mTOR signalling pathway was not activated in alpha(2A)/alpha(2C)ARKO mice. Exercise training improved cardiac function and exercise capacity in alpha(2A)/alpha(2C)ARKO mice and decreased heart weight and cardiomyocyte width paralleled by diminished nuclear NFATc3 and GATA-4 translocation as well as GATA-4 expression levels. When combined, these findings support the notion that deactivation of calcineurin/NFAT pathway-induced pathological hypertrophy is a preferential mechanism by which exercise training leads to the cardiac anti-remodelling effect in heart failure.
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beta-blockers, as class, improve cardiac function and survival in heart failure (HF). However, the molecular mechanisms underlying these beneficial effects remain elusive. In the present study, metoprolol and carvedilol were used in doses that display comparable heart rate reduction to assess their beneficial effects in a genetic model of sympathetic hyperactivity-induced HF (alpha(2A)/alpha(2C)-ARKO mice). Five month-old HF mice were randomly assigned to receive either saline, metoprolol or carvedilol for 8 weeks and age-matched wild-type mice (WT) were used as controls. HF mice displayed baseline tachycardia, systolic dysfunction evaluated by echocardiography, 50% mortality rate, increased cardiac myocyte width (50%) and ventricular fibrosis (3-fold) compared with WT. All these responses were significantly improved by both treatments. Cardiomyocytes from HF mice showed reduced peak [Ca(2+)](i) transient (13%) using confocal microscopy imaging. Interestingly, while metoprolol improved [Ca(2+)](i) transient, carvedilol had no effect on peak [Ca(2+)](i) transient but also increased [Ca(2+)] transient decay dynamics. We then examined the influence of carvedilol in cardiac oxidative stress as an alternative target to explain its beneficial effects. Indeed, HF mice showed 10-fold decrease in cardiac reduced/oxidized glutathione ratio compared with WT, which was significantly improved only by carvedilol treatment. Taken together, we provide direct evidence that the beneficial effects of metoprolol were mainly associated with improved cardiac Ca(2+) transients and the net balance of cardiac Ca(2+) handling proteins while carvedilol preferentially improved cardiac redox state. (C) 2008 Elsevier Inc. All rights reserved.
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Background: Studies have shown that the autonomic dysfunction accompanied by impaired baroreflex sensitivity was associated with higher mortality. However, the influence of decreased baroreflex sensitivity on cardiac function, especially in diastolic function, is not well understood. This study evaluated the morpho-functional changes associated with baroreflex impairment induced by chronic sinoaortic denervation (SAD). Methods and Results: Animals were divided into sinoaortic denervation (SAD) and control (C) groups. Baroreflex sensitivity was evaluated by tachycardic and bradycardic responses, induced by vasoactive drugs. Cardiac function was studied by echocardiography and by left ventricle (LV) catheterization. LV collagen content and the expression of regulatory proteins involved in intracellular Ca(2+) homeostasis were quantified. Results showed higher LV mass in SAD versus C animals. Furthermore, an increase in deceleration time of E-wave in the SAD versus the C group (2.14 +/- 0.07 ms vs 1.78 +/- 0.03 ms) was observed. LV end-diastolic pressure was increased and the minimum dP/dt was decreased in the SAD versus the C group (12 +/- 1.5 mm Hg vs 5.3 +/- 0.2 mm Hg and 7,422 +/- 201 vs 4,999 +/- 345 mm Hg/s, respectively). SERCA/NCX ratio was lower in SAD than in control rats. The same was verified in SERCA/PLB ratio. Conclusions: The results suggest that baroreflex dysfunction is associated with cardiac diastolic dysfunction independently of the presence of other risk factors. (J Cardiac Fail 2011;17:519-525)
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Soci UPR, Fernandes T, Hashimoto NY, Mota GF, Amadeu MA, Rosa KT, Irigoyen MC, Phillips MI, Oliveira EM. MicroRNAs 29 are involved in the improvement of ventricular compliance promoted by aerobic exercise training in rats. Physiol Genomics 43: 665-673, 2011. First published March 29, 2011; doi:10.1152/physiolgenomics.00145.2010.-MiRNAs regulate cardiac development, hypertrophy, and angiogenesis, but their role in cardiac hypertrophy (CH) induced by aerobic training has not previously been studied. Aerobic training promotes physiological CH preserving cardiac function. This study assessed involvement of miRNAs-29 in CH of trained rats. Female Wistar rats (n = 7/group) were randomized into three groups: sedentary (S), training 1 (T1), training 2 (T2). T1: swimming sessions of 60 min/5 days/wk/10 wk. T2: similar to T1 until 8th wk. On the 9th wk rats swam 2x/day, and on the 10th wk 3x/day. MiRNAs analysis was performed by miRNA microarray and confirmed by real-time PCR. We assessed: markers of training, CH by ratio of left ventricle (LV) weight/body wt and cardiomyocytes diameter, pathological markers of CH (ANF, skeletal alpha-actin, alpha/beta-MHC), collagen I and III (COLIAI and COLIIIAI) by real-time PCR, protein collagen by hydroxyproline (OH-proline) concentration, CF and CH by echocardiography. Training improved aerobic capacity and induced CH. MiRNAs-1, 133a, and 133b were downregulated as observed in pathological CH, however, without pathological markers. MiRNA-29c expression increased in T1 (52%) and T2 (123%), correlated with a decrease in COLIAI and COLIIIAI expression in T1 (27%, 38%) and T2 (33%, 48%), respectively. MiRNA-29c was inversely correlated to OH-proline concentration (r = 0.61, P = 0.05). The E/A ratio increased in T2, indicating improved LV compliance. Thus, these results show that aerobic training increase miR-29 expression and decreased collagen gene expression and concentration in the heart, which is relevant to the improved LV compliance and beneficial cardiac effects, associated with aerobic high performance training.
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Study design: This is cross-sectional study. Objectives: The aim of this study is to investigate the cardiac structure and function of subjects with spinal cord injury (SCI) and the impact of metabolic, hemodynamic and inflammatory factors on these parameters. Setting: Sao Paulo, Brazil. Methods: Sixty-five nondiabetic, nonhypertensive, sedentary, nonsmoker men (34 with SCI and 31 healthy subjects) were evaluated by medical history, anthropometry, laboratory tests, analysis of hemodynamic and inflammatory parameters and echocardiography. Results: Subjects with SCI had lower systolic blood pressure and higher levels of C-reactive protein and tumor necrosis factor receptors than the healthy ones. Echocardiography data showed that the SCI group presented similar left ventricular (LV) structural and systolic parameters, but lower initial diastolic velocity (Em) (9.2 +/- 0.5 vs 12.3 +/- 0.5 cm s(-1); P<0.001) and higher peak early inflow velocity (E)/Em ratio (7.7 +/- 0.5 vs 6.1 +/- 0.3; P = 0.009) compared with the able-bodied group, even after adjustment for systolic blood pressure and C-reactive protein levels. Furthermore, injured subjects with E/Em >8 had lower peak spectral longitudinal contraction (Sm) (9.0 +/- 0.7 vs 11.6 +/- 0.4cm s(-1); P<0.001) and cardiac output (4.2 +/- 0.2 vs 5.0 +/- 0.21 min(-1); P = 0.029), as well as higher relative wall thickness (0.38 +/- 0.01 vs 0.35 +/- 0.01; P = 0.005), than individuals with SCI with E/Em<8, but similar age, body mass index, blood pressure, injury level, metabolic parameters and inflammatory marker levels. Conclusion: Subjects with SCI presented impaired LV diastolic function in comparison with able-bodied ones. Moreover, worse LV diastolic function was associated with a pattern of LV concentric remodeling and subclinical decreases in systolic function among injured subjects. Overall, these findings might contribute to explain the increased cardiovascular risk reported for individuals with SCI. Spinal Cord (2011) 49, 65-69; doi: 10.1038/sc.2010.88; published online 27 July 2010
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One of the most important recent improvements in cardiology is the use of ventricular assist devices (VADs) to help patients with severe heart diseases, especially when they are indicated to heart transplantation. The Institute Dante Pazzanese of Cardiology has been developing an implantable centrifugal blood pump that will be able to help a sick human heart to keep blood flow and pressure at physiological levels. This device will be used as a totally or partially implantable VAD. Therefore, an improvement on device performance is important for the betterment of the level of interaction with patient`s behavior or conditions. But some failures may occur if the device`s pumping control does not follow the changes in patient`s behavior or conditions. The VAD control system must consider tolerance to faults and have a dynamic adaptation according to patient`s cardiovascular system changes, and also must attend to changes in patient conditions, behavior, or comportments. This work proposes an application of the mechatronic approach to this class of devices based on advanced techniques for control, instrumentation, and automation to define a method for developing a hierarchical supervisory control system that is able to perform VAD control dynamically, automatically, and securely. For this methodology, we used concepts based on Bayesian network for patients` diagnoses, Petri nets to generate a VAD control algorithm, and Safety Instrumented Systems to ensure VAD system security. Applying these concepts, a VAD control system is being built for method effectiveness confirmation.
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A new digital computer mock circulatory system has been developed in order to replicate the physiologic and pathophysiologic characteristics of the human cardiovascular system. The computer performs the acquisition of pressure, flow, and temperature in an open loop system. A computer program has been developed in Labview programing environment to evaluate all these physical parameters. The acquisition system was composed of pressure, flow, and temperature sensors and also signal conditioning modules. In this study, some results of flow, cardiac frequencies, pressures, and temperature were evaluated according to physiologic ventricular states. The results were compared with literature data. In further works, performance investigations will be conducted on a ventricular assist device and endoprosthesis. Also, this device should allow for evaluation of several kinds of vascular diseases.
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In previous studies, we presented main strategies for suspending the rotor of a mixed-flow type (centrifugal and axial) ventricular assist device (VAD), originally presented by the Institute Dante Pazzanese of Cardiology (IDPC), Brazil. Magnetic suspension is achieved by the use of a magnetic bearing architecture in which the active control is executed in only one degree of freedom, in the axial direction of the rotor. Remaining degrees of freedom, excepting the rotation, are restricted only by the attraction force between pairs of permanent magnets. This study is part of a joint project in development by IDPC and Escola Politecnica of Sao Paulo University, Brazil. This article shows advances in that project, presenting two promising solutions for magnetic bearings. One solution uses hybrid cores as electromagnetic actuators, that is, cores that combine iron and permanent magnets. The other solution uses actuators, also of hybrid type, but with the magnetic circuit closed by an iron core. After preliminary analysis, a pump prototype has been developed for each solution and has been tested. For each prototype, a brushless DC motor has been developed as the rotor driver. Each solution was evaluated by in vitro experiments and guidelines are extracted for future improvements. Tests have shown good results and demonstrated that one solution is not isolated from the other. One complements the other for the development of a single-axis-controlled, hybrid-type magnetic bearing for a mixed-flow type VAD.
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This work presents results of preliminary studies concerning application of magnetic bearing in a ventricular assist device (VAD) being developed by Dante Pazzanese Institute of Cardiology-IDPC (Sao Paulo, Brazil). The VAD-IDPC has a novel architecture that distinguishes from other known VADs. In this, the rotor has a conical geometry with spiral impellers, showing characteristics that are intermediate between a centrifugal VAD and an axial VAD. The effectiveness of this new type of blood pumping principle was showed by tests and by using it in heart surgery for external blood circulation. However, the developed VAD uses a combination of ball bearings and mechanical seals, limiting the life for some 10 h, making impossible its long-term use or its use as an implantable VAD. As a part of development of an implantable VAD, this work aims at the replacement of ball bearings by a magnetic bearing. The most important magnetic bearing principles are studied and the magnetic bearing developed by Escola Politecnica of Sao Paulo University (EPUSP-MB) is elected because of its very simple architecture. Besides presenting the principle of the EPUSP-MB, this work presents one possible alternative for applying the EPUSP-MB in the IDPC-VAD.