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Biomedical subjects

Blase A Carabello

Publications and source records attributed to Blase A Carabello.

At least 19 recordsLinked to original sources

Herpes zoster and its cardiovascular complications in the elderly--another look at a dormant virus.

Herpes zoster (shingles) is a reactivation of latent Varicella-zoster virus (VZV). We present a case of pleuropericarditis simulating acute myocardial infarction and another with complete heart block in the setting of acute/recent VZV reactivation. These cases are consistent with a modified concept: (1) the VZV dormancy is comprised of multiple foci of infections in the sensory and autonomic ganglia, and (2) the VZV reactivation could involve co-incident activations of two or more loci. Recognition of this possibility of cardiovascular complications of VZV should be helpful in the clinical management of the elderly, in the differential diagnosis of chest pain, ST elevation, and heart block etiology in the setting of acute or recent VZV reactivation.

Aged↗

Malignant pleural/pericardial effusion with tamponade and life-threatening reversible myocardial depression in a case of an initial presentation of lung adenocarcinoma.

We present a case of a middle-aged woman in cardiac tamponade. Following pericardiocentesis that removed 1,500 ml of hemorrhagic fluid, the patient exhibited cardiogenic shock; LVEF, at its nadir, on inotrope, was less than 20%. Ventricular function slowly improved, with inotropic support, to the normal range by the 25th day of hospitalization. Cardiac failure in malignancy has often been attributed to multi-system failure; this case showed a hereto unrecognized clinical phenomenon - 'malignancy-associated myopericarditis'. While the direct link of cause and effect cannot be made with certainty, the case should be instructive to other clinicians who encounter similar life-threatening presentations of cardiac decompensation in malignancy.

Adenocarcinoma↗

PPAR-gamma agonist rosiglitazone ameliorates ventricular dysfunction in experimental chronic mitral regurgitation.

Previously we reported that the beneficial effects of beta-adrenergic blockade in chronic mitral regurgitation (MR) were in part due to induction of bradycardia, which obviously affects myocardial energy requirements. From this observation we hypothesized that part of the pathophysiology of MR may involve faulty energy substrate utilization, which in turn might lead to potentially harmful lipid accumulation as observed in other models of heart failure. To explore this hypothesis, we measured triglyceride accumulation in the myocardia of dogs with chronic MR and then attempted to enhance myocardial metabolism by chronic administration of the peroxisome proliferator-activated receptor (PPAR)-gamma agonist rosiglitazone. Cardiac tissues were obtained from three groups of dogs that included control animals, dogs with MR for 3 mo without treatment, and dogs with MR for 6 mo that were treated with rosiglitazone (8 mg/day) for the last 3 mo of observation. Hemodynamics and contractile function (end-systolic stress-strain relationship, as measured by K index) were assessed at baseline, 3 mo of MR, and 6 mo of MR (3 mo of the treatment). Lipid accumulation in MR (as indicated by oil red O staining score and TLC analysis) was marked and showed an inverse correlation with the left ventricular (LV) contractility. LV contractility was significantly restored after PPAR therapy (K index: therapy, 3.01 +/- 0.11*; 3 mo MR, 2.12 +/- 0.34; baseline, 4.01 +/- 0.29; ANOVA, P = 0.038; *P < 0.05 vs. 3 mo of MR). At the same time, therapy resulted in a marked reduction of intramyocyte lipid. We conclude that 1) chronic MR leads to intramyocyte myocardial lipid accumulation and contractile dysfunction, and 2) administration of the PPAR-gamma agonist rosiglitazone ameliorates MR-induced LV dysfunction accompanied by a decline in lipid content.

Animals↗

Is it ever too late to operate on the patient with valvular heart disease?

All valvular heart disease imparts a hemodynamic burden on the left and/or right ventricle. This burden can only be removed effectively by correcting the responsible valvular lesion. Although a percutaneous approach is usually used to correct mitral stenosis, other valve lesions require surgical intervention. Over the past 40 years there has been a persistent improvement in our understanding of the pathophysiology of valvular heart disease and in the surgical techniques for correcting it. These factors have acted in concert to alter our view of the proper timing and applicability of surgery. On one hand it is no longer necessary or even advisable to delay surgery until advanced symptoms are present, and thus surgery is timed earlier today than it was even a decade ago. On the other hand, many but not all patients with far advanced disease, once considered inoperable, are now often helped substantially by valve surgery. However, selection of which of these very ill patients will or will not benefit from valve surgery remains a challenge for all of us. It is this group of patients that is addressed in the review.

Aortic Valve Insufficiency↗

Aldosterone, through novel signaling proteins, is a fundamental molecular bridge between the genetic defect and the cardiac phenotype of hypertrophic cardiomyopathy.

BACKGROUND: Human hypertrophic cardiomyopathy (HCM), the most common cause of sudden cardiac death in the young, is characterized by cardiac hypertrophy, myocyte disarray, and interstitial fibrosis. The genetic basis of HCM is largely known; however, the molecular mediators of cardiac phenotypes are unknown. METHODS AND RESULTS: We show myocardial aldosterone and aldosterone synthase mRNA levels were elevated by 4- to 6-fold in humans with HCM, whereas cAMP levels were normal. Aldosterone provoked expression of hypertrophic markers (NPPA, NPPB, and ACTA1) in rat cardiac myocytes by phosphorylation of protein kinase D (PKD) and expression of collagens (COL1A1, COL1A2, and COL3A1) and transforming growth factor-beta1 in rat cardiac fibroblasts by upregulation of phosphoinositide 3-kinase (PI3K)-p100delta. Inhibition of PKD and PI3K-p110delta abrogated the hypertrophic and profibrotic effects, respectively, as did the mineralocorticoid receptor (MR) antagonist spironolactone. Spironolactone reversed interstitial fibrosis, attenuated myocyte disarray by 50%, and improved diastolic function in the cardiac troponin T (cTnT)-Q92 transgenic mouse model of human HCM. Myocyte disarray was associated with increased levels of phosphorylated beta-catenin (serine 38) and reduced beta-catenin-N-cadherin complexing in the heart of cTnT-Q92 mice. Concordantly, distribution of N-cadherin, predominantly localized to cell membrane in normal myocardium, was diffuse in disarrayed myocardium. Spironolactone restored beta-catenin-N-cadherin complexing and cellular distribution of N-cadherin and reduced myocyte disarray in 2 independent randomized studies. CONCLUSIONS: The results implicate aldosterone as a major link between sarcomeric mutations and cardiac phenotype in HCM and, if confirmed in additional models, signal the need for clinical studies to determine the potential beneficial effects of MR blockade in human HCM.

Aged↗

Targeted overexpression of noncleavable and secreted forms of tumor necrosis factor provokes disparate cardiac phenotypes.

BACKGROUND: Recent studies suggest that posttranslation processing or "shedding" (ie, secretion) of tumor necrosis factor (TNF) by tumor necrosis factor-alpha converting enzyme (TACE) may contribute to the left ventricular (LV) remodeling that occurs in the failing human heart. METHODS AND RESULTS: To address the functional significance of TNF shedding, we generated lines of transgenic mice with targeted overexpression of secreted wild-type (MHCsTNF2) TNF and overexpression of a mutated noncleavable transmembrane form of TNF (MHCmTNF). Both lines of mice had overlapping levels of myocardial TNF protein; however, the phenotypes of the MHCsTNF2 and MHCmTNF mice were strikingly disparate. Whereas the MHCmTNF mice developed a concentric LV hypertrophy phenotype, the MHCsTNF2 mice developed a dilated LV phenotype. The fibrillar collagen weave in MHCmTNF mice with concentric hypertrophy was characterized by thick collagen fibrils and increased collagen content, whereas the fibrillar collagen weave in the MHCsTNF2 mice with LV dilation was characterized by a diminished collagen content. Inhibition of matrix metalloproteinases with a broad-based matrix metalloproteinase inhibitor prevented LV dilation in the MHCsTNF2 mice. CONCLUSIONS: These findings suggest that posttranslational processing of TNF, as opposed to TNF expression per se, is responsible for the adverse cardiac remodeling that occurs after sustained TNF overexpression.

Animals↗

Targeted overexpression of transmembrane tumor necrosis factor provokes a concentric cardiac hypertrophic phenotype.

BACKGROUND: Tumor necrosis factor (TNF) is initially synthesized as a 26-kDa transmembrane protein that is enzymatically cleaved by TNF-alpha converting enzyme (TACE) to generate a 17-kDa form of "secreted" TNF. Whereas the effects of secreted TNF in the heart have been characterized extensively, the effects of transmembrane TNF in the heart are unknown. METHODS AND RESULTS: We generated lines of transgenic mice with cardiac-restricted overexpression of a noncleavable, transmembrane form of TNF. We next treated a previously generated transgenic line of mice with cardiac-restricted expression of cleavable TNF (referred to as MHCsTNF mice) with a TACE inhibitor (DPC-IDR1) to determine whether TACE inhibition would prevent the transition from concentric hypertrophy to left ventricular (LV) dilation that occurs in this line of transgenic mice. Two of the founder lines did not have a demonstrable phenotype (M-41 and M-45), whereas a third line developed a concentric hypertrophic cardiac phenotype (M-48). Characterization of the M-48 line at 6 weeks of age showed that this line developed concentric hypertrophy, with an increase in myocyte cross-sectional area and reexpression of the fetal gene program. Four weeks of TACE inhibition abrogated the LV dilation in the MHCsTNF mice and resulted in an increase in LV wall thickness and increased myocyte cross-sectional area, thus mimicking the effects observed in the mice with noncleavable, transmembrane TNF. CONCLUSIONS: These studies show that transmembrane TNF is biologically active and provokes a concentric hypertrophic cardiac phenotype, thus suggesting that posttranslational processing (ie, secretion) of TNF is responsible for the dilated cardiomyopathic phenotype in mice with targeted, cardiac-restricted overexpression of TNF.

ADAM Proteins↗

CD14-deficient mice are protected against lipopolysaccharide-induced cardiac inflammation and left ventricular dysfunction.

BACKGROUND: The molecular mechanisms responsible for sepsis-induced myocardial dysfunction remain undefined. CD14 mediates the inflammatory response to lipopolysaccharide (LPS) in various organs including the heart. In this study we investigated the role of CD14 in LPS-induced myocardial dysfunction in vivo. METHODS AND RESULTS: Wild-type and CD14-deficient (CD14-D) mice were challenged with Escherichia coli LPS. Myocardial tumor necrosis factor, interleukin-1beta (IL-1beta), and NOS2 induction was measured before and 6 hours after LPS challenge. Echocardiographic parameters of left ventricular function were measured before and 6 hours after LPS administration. LPS challenge induced a significant increase in myocardial tumor necrosis factor and IL-1beta mRNA and protein expression in wild-type mice. In contrast, mRNA and protein levels for TNF and IL-1beta were significantly blunted in CD14-D mice. An increase in NOS2 protein was noted within 6 hours of LPS provocation only in the hearts of wild-type mice. This was associated with an increase in ventricular cGMP levels. Activation of nuclear factor-kappaB was observed within 30 minutes of LPS in the hearts of wild-type mice but not in CD14-D mice. In wild-type mice, LPS significantly decreased left ventricular fractional shortening, velocity of circumferential shortening, and dP/dt(max). LPS-treated CD14-D mice maintained normal cardiac function. CONCLUSIONS: These results suggest that CD14 is important in mediating the proinflammatory response induced by LPS in the heart and that CD14 is necessary for the development of left ventricular dysfunction during LPS-induced shock in vivo.

Animals↗

Differential effects of the angiotensin-converting enzyme inhibitor lisinopril versus the beta-adrenergic receptor blocker atenolol on hemodynamics and left ventricular contractile function in experimental mitral regurgitation.

OBJECTIVES: The goal of this study was to determine the therapeutic efficacy of angiotensin-converting enzyme (ACE) inhibitors and beta-adrenergic receptor blockers in experimental chronic mitral regurgitation (MR), gaining knowledge using methods difficult to apply in humans. BACKGROUND: Both ACE inhibitors and beta-blockers are cornerstones in the treatment of human congestive heart failure. However, the roles of these treatments for chronic MR is unclear. METHODS: Mitral regurgitation was created in 11 closed-chest dogs. Three months after the creation, the ACE inhibitor lisinopril 20 mg was given orally daily. After three months of lisinopril therapy, the beta-blocker atenolol was added to lisinopril for another three months. Atenolol was begun at a dose of 12.5 mg daily and increased gradually to 100 mg daily. Hemodynamics and left ventricular (LV) function were assessed throughout the study. RESULTS: Regurgitant fraction was consistently >50% over the course of this study. Pulmonary capillary wedge pressure and LV end-diastolic pressure were significantly increased after three months of MR and decreased during both lisinopril and the combined therapy in which it was not different from baseline. Left ventricular contractility measured by the end-systolic stiffness constant was depressed from 3.66 +/- 0.20 to 2.65 +/- 0.12 (p < 0.05) at three months of MR and rose insignificantly after lisinopril treatment (2.99 +/- 0.17). When atenolol was added, it rose significantly and returned to normal (3.50 +/- 0.22, p < 0.05). CONCLUSIONS: Although lisinopril significantly reduced preload, its effect on LV contractility was insignificant in experimental MR. Conversely, atenolol, when added to lisinopril, achieved maximum hemodynamic benefit and also restored LV contractility.

Adrenergic beta-Antagonists↗