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1.
Am J Med Sci ; 355(1): 3-5, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29289259

RESUMO

Cannabinoids, the bioactive components of marijuana, have adverse cardiovascular consequences, including symptomatic sinus bradycardia, sinus arrest and ventricular asystole. Physicians should be aware of these deleterious consequences which can appear in otherwise healthy persons who are chronic marijuana users.


Assuntos
Bradicardia/induzido quimicamente , Bradicardia/fisiopatologia , Canabinoides/efeitos adversos , Bradicardia/diagnóstico , Canabinoides/administração & dosagem , Teste de Esforço/efeitos dos fármacos , Teste de Esforço/métodos , Parada Cardíaca/induzido quimicamente , Parada Cardíaca/diagnóstico , Parada Cardíaca/fisiopatologia , Humanos
2.
Am J Med Sci ; 354(4): 335-338, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-29078836

RESUMO

Secondary hyperparathyroidism (SHPT) is a well-known pathophysiologic feature of chronic renal failure. In recent years, SHPT has become recognized as a complication of the aldosteronism associated with congestive heart failure and where excretory Ca2+ and Mg2+ wasting results in plasma-ionized hypocalcemia and hypomagnesemia. Elevations in plasma parathyroid hormone have adverse systemic consequences, including intracellular Ca2+ overloading of myocytes and vascular smooth muscle with the induction of oxidative stress. Herein, we briefly review the presence and adverse outcomes of SHPT in persons with heart failure.


Assuntos
Cálcio/sangue , Insuficiência Cardíaca/sangue , Hiperparatireoidismo Secundário/sangue , Magnésio/sangue , Hormônio Paratireóideo/sangue , Insuficiência Renal Crônica/sangue , Animais , Insuficiência Cardíaca/patologia , Insuficiência Cardíaca/fisiopatologia , Humanos , Hiperparatireoidismo Secundário/patologia , Hiperparatireoidismo Secundário/fisiopatologia , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patologia , Músculo Liso Vascular/fisiopatologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Insuficiência Renal Crônica/patologia , Insuficiência Renal Crônica/fisiopatologia
3.
Am J Med Sci ; 353(5): 422-424, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28502326

RESUMO

Acute stressor states are linked to neurohormonal activation that includes the adrenergic nervous system. Elevations in circulating epinephrine and norepinephrine unmask an interdependency that exists between K+ and Mg2+ based on their regulation of a large number of Mg2+-dependent Na+-K+-ATPase pumps present in skeletal muscle. The hyperadrenergic state accounts for a sudden translocation of cations into muscle with the rapid appearance of hypokalemia and hypomagnesemia. The resultant hypokalemia and hypomagnesemia will cause a delay in myocardial repolarization and electrocardiographic QTc prolongation raising the propensity for supraventricular and ventricular arrhythmias. In this review, we focus on the interdependency between K+ and Mg2+, which is clinically relevant to acute hyperadrenergic stressor states found in patients admitted to intensive care units.


Assuntos
Hipopotassemia/etiologia , Deficiência de Magnésio/etiologia , Deficiência de Potássio/etiologia , Estresse Fisiológico , Cátions/metabolismo , Homeostase , Humanos
4.
Am J Hypertens ; 30(11): 1049-1052, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-28379281

RESUMO

Established cardiac fibrosis (ECF) with symptomatic heart failure preserved ejection fraction represents an ever-increasing segment of the hypertensive population. The regression of ECF with attendant improvement in myocardial stiffness and symptomatic failure represents an unmet health care need. Is the regression of ECF in hypertensive heart disease feasible and will stiffness and symptomatic failure be improved? What is the cellular/molecular signaling involved in its regression? What incremental knowledge is needed to proceed effectively? These issues are addressed in this Review.


Assuntos
Pressão Sanguínea , Cardiomiopatias/etiologia , Insuficiência Cardíaca/etiologia , Hipertensão/complicações , Miocárdio/patologia , Remodelação Ventricular , Animais , Anti-Hipertensivos/uso terapêutico , Cardiomiopatias/metabolismo , Cardiomiopatias/patologia , Cardiomiopatias/fisiopatologia , Fibrose , Insuficiência Cardíaca/patologia , Insuficiência Cardíaca/fisiopatologia , Humanos , Hipertensão/diagnóstico , Hipertensão/tratamento farmacológico , Hipertensão/fisiopatologia , Miocárdio/metabolismo , Miofibroblastos/metabolismo , Miofibroblastos/patologia , Indução de Remissão , Transdução de Sinais , Resultado do Tratamento , Remodelação Ventricular/efeitos dos fármacos
5.
Am J Med Sci ; 352(4): 428-432, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27776727

RESUMO

Current dogma suggests patients with advanced systolic heart failure have an irreversible depression in myocardial contractility. Recent experience with improved ventricular function during continuous flow ventricular assist devices used as destination therapy would suggest otherwise. Herein, cellular and molecular signaling involved in reversing depressed myocardial contractility would be addressed. This includes cardiomyocyte thyroid hormone signaling responsible for the reexpression of fetal gene program that preserves cell efficiency (work and energy consumed) and the rescue of an endogenous population of atrophic myocytes bordering on microdomains of fibrosis to improve contractile mass.


Assuntos
Insuficiência Cardíaca/terapia , Contração Miocárdica , Miócitos Cardíacos/metabolismo , Animais , Regulação da Expressão Gênica , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/fisiopatologia , Humanos , Estresse Oxidativo , Hormônios Tireóideos/metabolismo
6.
JAMA Cardiol ; 1(5): 607-12, 2016 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-27434136

RESUMO

IMPORTANCE: Heart failure (HF), with or without reduced ejection fraction, and multidrug-resistant hypertension (RHT) are major worldwide health problems of ever-increasing proportions. The mineralocorticoid receptor antagonists (MRAs) spironolactone and eplerenone have proved valuable additions to the overall management of these disorders in patients without significant renal dysfunction. OBSERVATIONS: Neurohormonal activation, including aldosteronism, in HF and RHT, has provided the pathophysiologic basis for the inclusion of MRA in the overall management of these disorders and the respective survival benefit and control of blood pressure. Furthermore, MRAs attenuate the appearance of secondary hyperparathyroidism that accompanies excretory Ca2+ losses induced by aldosteronism in which elevated parathyroid hormone levels raise the risk of adverse cardiovascular events and atraumatic bone fracture. Serial surveillance of serum electrolytes and creatinine levels is mandated to avoid serious hyperkalemia (potassium concentration >5.5 mEq/L) and its attendant risks in patients receiving MRAs. CONCLUSIONS AND RELEVANCE: Mineralocorticoid receptor antagonists are a valuable addition to the practice of medicine. Their judicious use in patients with HF or RHT can improve treatment of these patients.


Assuntos
Insuficiência Cardíaca/tratamento farmacológico , Hipertensão/tratamento farmacológico , Antagonistas de Receptores de Mineralocorticoides/uso terapêutico , Espironolactona/análogos & derivados , Espironolactona/uso terapêutico , Eplerenona , Humanos , Hiperpotassemia , Disfunção Ventricular Esquerda
8.
Heart Fail Rev ; 21(2): 191-8, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26872676

RESUMO

Cardiomyocytes must be responsive to demands placed on the heart's contractile work as a muscular pump. In turn, myocyte size is largely dependent on the workload they perform. Both hypertrophied and atrophic myocytes are found in the normal and diseased ventricle. Individual myocytes become atrophic when encumbered by fibrillar collagen, such as occurs at sites of fibrosis. The mechanisms include: (a) being immobilized and subject to disuse with ensuing protein degradation mediated by redox-sensitive, proteolytic ligases of the ubiquitin-proteasome system and (b) dedifferentiated re-expressing fetal genes induced by low intracellular triiodothyronine (T3) via thyroid hormone receptor ß1. This myocyte-selective, low T3 state is a consequence of heterocellular signaling emanating from juxtaposed scar tissue myofibroblasts and their secretome with its de novo generation of angiotensin II. In a paracrine manner, angiotensin II promotes myocyte Ca(2+) entry and subsequent Ca(2+) overload with ensuing oxidative stress that overwhelms antioxidant defenses to activate deiodinase-3 and its enzymatic degradation of T3. In the failing heart, atrophic myocytes represent an endogenous population of viable myocytes which could be rescued to augment contractile mass, reduce systolic wall stress (afterload) and recover ventricular function. Experimental studies have shown the potential for the rescue and recovery of atrophic myocytes in rebuilding the myocardium--a method complementary to today's quest in regenerating myocardium using progenitor cells.


Assuntos
Angiotensina II/metabolismo , Antioxidantes/farmacologia , Insuficiência Cardíaca/fisiopatologia , Miócitos Cardíacos/patologia , Miofibroblastos/metabolismo , Função Ventricular , Humanos , Contração Miocárdica , Estresse Oxidativo , Transdução de Sinais
9.
Expert Rev Cardiovasc Ther ; 14(5): 591-8, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26818589

RESUMO

Myofibroblasts (myoFb) are phenotypically transformed, contractile fibroblast-like cells expressing α-smooth muscle actin microfilaments. They are integral to collagen fibrillogenesis with scar tissue formation at sites of repair irrespective of the etiologic origins of injury or tissue involved. MyoFb can persist long after healing is complete, where their ongoing turnover of collagen accounts for a progressive structural remodeling of an organ (a.k.a. fibrosis, sclerosis or cirrhosis). Such persistent metabolic activity is derived from a secretome consisting of requisite components in the de novo generation of angiotensin (Ang) II. Autocrine and paracrine signaling induced by tissue AngII is expressed via AT1 receptor ligand binding to respectively promote: i) regulation of myoFb collagen synthesis via the fibrogenic cytokine TGF-ß1-Smad pathway; and ii) dedifferentiation and protein degradation of atrophic myocytes immobilized and ensnared by fibrillar collagen at sites of scarring. Several cardioprotective strategies in the prevention of fibrosis and involving myofibroblasts are considered. They include: inducing myoFb apoptosis through inactivation of antiapoptotic proteins; AT1 receptor antagonist to interfere with auto-/paracrine myoFb signaling or to induce counterregulatory expression of ACE2; and attacking the AngII-AT1R-TGF-ß1-Smad pathway by antibody or the use of triplex-forming oligonucleotides.


Assuntos
Colágeno/metabolismo , Miofibroblastos/metabolismo , Comunicação Parácrina/fisiologia , Angiotensina II/metabolismo , Fibroblastos/metabolismo , Fibrose/patologia , Humanos , Cicatrização/fisiologia
10.
Am J Transl Res ; 7(4): 697-709, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26064438

RESUMO

BACKGROUND: Numerous studies have shown that in addition to angio/lymphangiogenesis, the VEGF family is involved in other cellular actions. We have recently reported that enhanced VEGF-C and VEGFR-3 in the infarcted rat myocardium, suggesting the paracrine/autocrine function of VEGF-C on cardiac remodeling. The current study was designed to test the hypothesis that VEGF-C regulates cardiomyocyte growth and survival in the infarcted myocardium. METHODS AND RESULTS: Gene profiling and VEGFR-3 expression of cardiomyocytes were assessed by laser capture microdissection/microarray and immunohistochemistry in the normal and infarcted myocardium. The effect of VEGF-C on myocyte hypertrophy and apoptosis during normoxia and hypoxia was detected by RT-PCR and western blotting in cultured rat neonatal cardiomyocytes. VEGFR-3 was minimally expressed in cardiomyocytes of the normal and noninfarcted myocardium, while markedly elevated in the surviving cardiomyocytes of the infarcted myocardium and border zone. Genes altered in the surviving cardiomyocytes were associated with the networks regulating cellular growth and survival. VEGF-C significantly increased the expression of atrial natriuretic factor (ANP), brain natriuretic factor (BNP), and ß-myosin heavy chain (MHC), markers of hypertrophy, in neonatal cardiomyocytes. Hypoxia caused neonatal cardiomyocyte atrophy, which was prevented by VEGF-C treatment. Hypoxia significantly enhanced apoptotic mediators, including cleaved caspase 3, 8, and 9, and Bax in neonatal cardiomyocytes, which were abolished by VEGF-C treatment. CONCLUSION: Our findings indicate that VEGF-C/VEGFR-3 pathway exerts a beneficial role in the infarcted myocardium by promoting compensatory cardiomyocyte hypertrophy and survival.

11.
J Cardiovasc Pharmacol ; 64(4): 393-400, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25291496

RESUMO

Neurohormonal activation with attendant aldosteronism contributes to the clinical appearance of congestive heart failure (CHF). Aldosteronism is intrinsically coupled to Zn and Ca dyshomeostasis, in which consequent hypozincemia compromises Zn homeostasis and Zn-based antioxidant defenses that contribute to the CHF prooxidant phenotype. Ionized hypocalcemia leads to secondary hyperparathyroidism with parathyroid hormone-mediated Ca overloading of diverse cells, including cardiomyocytes. When mitochondrial Ca overload exceeds a threshold, myocyte necrosis follows. The reciprocal regulation involving cytosolic free [Zn]i as antioxidant and [Ca]i as prooxidant can be uncoupled in favor of Zn-based antioxidant defenses. Increased [Zn]i acts as a multifaceted antioxidant by: (1) inhibiting Ca entry through L-type channels and hence cardioprotectant from the Ca-driven mitochondriocentric signal-transducer effector pathway to nonischemic necrosis, (2) serving as catalytic regulator of Cu/Zn-superoxide dismutase, and (3) activating its cytosolic sensor, metal-responsive transcription factor that regulates the expression of relevant antioxidant defense genes. Albeit present in subnanomolar range, increased cytosolic free [Zn]i enhances antioxidant capacity that confers cardioprotection. It can be achieved exogenously by ZnSO4 supplementation or endogenously using a ß3-receptor agonist (eg, nebivolol) that enhances NO generation to release inactive cytosolic Zn bound to metallothionein. By recognizing the pathophysiologic relevance of Zn dyshomeostasis in the prooxidant CHF phenotype and by exploiting the pharmacophysiologic potential of [Zn]i as antioxidant, vulnerable cardiomyocytes under assault from neurohormonal activation can be protected and the myocardium spared from adverse structural remodeling.


Assuntos
Antioxidantes/uso terapêutico , Cardiotônicos/uso terapêutico , Insuficiência Cardíaca/tratamento farmacológico , Estresse Oxidativo/efeitos dos fármacos , Zinco/uso terapêutico , Animais , Antioxidantes/administração & dosagem , Antioxidantes/metabolismo , Cálcio/metabolismo , Cardiotônicos/administração & dosagem , Cardiotônicos/metabolismo , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/patologia , Homeostase , Humanos , Necrose , Zinco/administração & dosagem , Zinco/metabolismo
12.
Int J Mol Sci ; 15(6): 9285-301, 2014 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-24865490

RESUMO

Mitochondria are complex organelles that play critical roles in diverse aspects of cellular function. Heart disease and a number of other pathologies are associated with perturbations in the molecular machinery of the mitochondria. Therefore, comprehensive, unbiased examination of the mitochondrial proteome represents a powerful approach toward system-level insights into disease mechanisms. A crucial aspect in proteomics studies is design of bioanalytical strategies that maximize coverage of the complex repertoire of mitochondrial proteins. In this study, we evaluated the performance of gel-based and gel-free multidimensional platforms for profiling of the proteome in subsarcolemmal mitochondria harvested from rat heart. We compared three different multidimensional proteome fractionation platforms: polymeric reversed-phase liquid chromatography at high pH (PLRP), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and isoelectric focusing (IEF) separations combined with liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS), and bioinformatics for protein identification. Across all three platforms, a total of 1043 proteins were identified. Among the three bioanalytical strategies, SDS-PAGE followed by LC-MS/MS provided the best coverage of the mitochondrial proteome. With this platform, 890 proteins with diverse physicochemical characteristics were identified; the mitochondrial protein panel encompassed proteins with various functional roles including bioenergetics, protein import, and mitochondrial fusion. Taken together, results of this study provide a large-scale view of the proteome in subsarcolemmal mitochondria from the rat heart, and aid in the selection of optimal bioanalytical platforms for differential protein expression profiling of mitochondria in health and disease.


Assuntos
Mitocôndrias/química , Proteínas Mitocondriais/análise , Miócitos Cardíacos/química , Proteoma/análise , Proteômica/métodos , Acetilação , Animais , Cromatografia Líquida/métodos , Cromatografia de Fase Reversa/métodos , Eletroforese em Gel de Poliacrilamida/métodos , Focalização Isoelétrica/métodos , Ratos , Ratos Sprague-Dawley , Espectrometria de Massas em Tandem/métodos
13.
J Cardiovasc Pharmacol ; 64(3): 237-46, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24785345

RESUMO

With the perspective of functional myocardial regeneration, we investigated small cardiomyocytes bordering on microdomains of fibrosis, where they are dedifferentiated re-expressing fetal genes, and determined: (1) whether they are atrophied segments of the myofiber syncytium, (2) their redox state, (3) their anatomic relationship to activated myofibroblasts (myoFb), given their putative regulatory role in myocyte dedifferentiation and redifferentiation, (4) the relevance of proteolytic ligases of the ubiquitin-proteasome system as a mechanistic link to their size, and (5) whether they could be rescued from their dedifferentiated phenotype. Chronic aldosterone/salt treatment (ALDOST) was invoked, where hypertensive heart disease with attendant myocardial fibrosis creates the fibrillar collagen substrate for myocyte sequestration, with propensity for disuse atrophy, activated myoFb, and oxidative stress. To address phenotype rescue, 4 weeks of ALDOST was terminated followed by 4 weeks of neurohormonal withdrawal combined with a regimen of exogenous antioxidants, ZnSO4, and nebivolol (assisted recovery). Compared with controls, at 4 weeks of ALDOST, we found small myocytes to be: (1) sequestered by collagen fibrils emanating from microdomains of fibrosis and representing atrophic segments of the myofiber syncytia, (2) dedifferentiated re-expressing fetal genes (ß-myosin heavy chain and atrial natriuretic peptide), (3) proximal to activated myoFb expressing α-smooth muscle actin microfilaments and angiotensin-converting enzyme, (4) expressing reactive oxygen species and nitric oxide with increased tissue 8-isoprostane, coupled to ventricular diastolic and systolic dysfunction, and (5) associated with upregulated redox-sensitive proteolytic ligases MuRF1 and atrogin-1. In a separate study, we did not find evidence of myocyte replication (BrdU labeling) or expression of stem cell antigen (c-Kit) at weeks 1-4 ALDOST. Assisted recovery caused complete disappearance of myoFb from sites of fibrosis with redifferentiation of these myocytes, loss of oxidative stress, and ubiquitin-proteasome system activation, with restoration of nitric oxide and improved ventricular function. Thus, small dedifferentiated myocytes bordering on microdomains of fibrosis can re-differentiate and represent a potential source of autologous cells for functional myocardial regeneration.


Assuntos
Antioxidantes/metabolismo , Desdiferenciação Celular/fisiologia , Diferenciação Celular/fisiologia , Miócitos Cardíacos/metabolismo , Aldosterona/farmacologia , Animais , Antioxidantes/administração & dosagem , Fibrose , Hipertensão/fisiopatologia , Masculino , Miócitos Cardíacos/citologia , Miócitos Cardíacos/patologia , Miofibroblastos/metabolismo , Óxido Nítrico/metabolismo , Oxirredução , Estresse Oxidativo/fisiologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Regeneração/fisiologia , Ubiquitina/metabolismo
14.
Mol Cell Biochem ; 389(1-2): 159-67, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24395194

RESUMO

Mitochondria are complex organelles essential to cardiomyocyte survival. Protein phosphorylation is emerging as a key regulator of mitochondrial function. In the study reported here, we analyzed subsarcolemmal (SSM) mitochondria harvested from rats who have received 4 weeks of aldosterone/salt treatment to simulate the neurohormonal profile of human congestive heart failure. Our objective was to obtain an initial qualitative inventory of the phosphoproteins in this biologic system. SSM mitochondria were harvested, and the phosphoproteome was analyzed with a gel-free bioanalytical platform. Mitochondrial proteins were digested with trypsin, and the digests were enriched for phosphopeptides with immobilized metal ion affinity chromatography. The phosphopeptides were analyzed by ion trap liquid chromatography-tandem mass spectrometry, and the phosphoproteins identified via database searches. Based on MS/MS and MS(3) data, we characterized a set of 42 phosphopeptides that encompassed 39 phosphorylation sites. These peptides mapped to 26 proteins, for example, long-chain specific acyl-CoA dehydrogenase, Complex III subunit 6, and mitochondrial import receptor TOM70. Collectively, the characterized phosphoproteins belong to diverse functional modules, including bioenergetic pathways, protein import machinery, and calcium handling. The phosphoprotein panel discovered in this study provides a foundation for future differential phosphoproteome profiling toward an integrated understanding of the role of mitochondrial phosphorylation in heart failure.


Assuntos
Insuficiência Cardíaca/metabolismo , Mitocôndrias/metabolismo , Miócitos Cardíacos/metabolismo , Fosfoproteínas/metabolismo , Proteoma/metabolismo , Animais , Masculino , Mapeamento de Peptídeos/métodos , Peptídeos/metabolismo , Proteômica/métodos , Ratos , Ratos Sprague-Dawley
15.
J Cardiovasc Pharmacol ; 62(6): 497-506, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24084216

RESUMO

Cardinal pathological features of hypertensive heart disease (HHD) include not only hypertrophied cardiomyocytes and foci of scattered microscopic scarring, a footprint of prior necrosis, but also small myocytes ensnared by fibrillar collagen where disuse atrophy with protein degradation would be predicted. Whether atrophic signaling is concordant with the appearance of HHD and involves oxidative and endoplasmic reticulum (ER) stress remains unexplored. Herein, we examine these possibilities focusing on the left ventricle and cardiomyocytes harvested from hypertensive rats receiving 4 weeks aldosterone/salt treatment (ALDOST) alone or together with ZnSO4, a nonvasoactive antioxidant, with the potential to attenuate atrophy and optimize hypertrophy. Compared with untreated age-/sex-/strain-matched controls, ALDOST was accompanied by (1) left ventricle hypertrophy with preserved systolic function; (2) concordant cardiomyocyte atrophy (<1000 µm²) found at sites bordering on fibrosis where they were reexpressing ß-myosin heavy chain; and (3) upregulation of ubiquitin ligases, muscle RING-finger protein-1 and atrogin-1, and elevated 8-isoprostane and unfolded protein ER response with messenger RNA upregulation of stress markers. ZnSO4 cotreatment reduced lipid peroxidation, fibrosis, and the number of atrophic myocytes, together with a further increase in cell area and width of atrophied and hypertrophied myocytes, and improved systolic function but did not attenuate elevated blood pressure. We conclude that atrophic signaling, concordant with hypertrophy, occurs in the presence of a reparative fibrosis and induction of oxidative and ER stress at sites of scarring where myocytes are atrophied. ZnSO4 cotreatment in HHD with ALDOST attenuates the number of atrophic myocytes, optimizes size of atrophied and hypertrophied myocytes, and improves systolic function.


Assuntos
Modelos Animais de Doenças , Hipertensão/metabolismo , Hipertrofia Ventricular Esquerda/etiologia , Proteínas Musculares/metabolismo , Miócitos Cardíacos/metabolismo , Proteínas Ligases SKP Culina F-Box/metabolismo , Transdução de Sinais , Ubiquitina-Proteína Ligases/metabolismo , Animais , Anti-Hipertensivos/farmacologia , Anti-Hipertensivos/uso terapêutico , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Cardiotônicos/farmacologia , Cardiotônicos/uso terapêutico , Tamanho Celular/efeitos dos fármacos , Células Cultivadas , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Ventrículos do Coração/efeitos dos fármacos , Ventrículos do Coração/metabolismo , Ventrículos do Coração/patologia , Hipertensão/tratamento farmacológico , Hipertensão/patologia , Hipertensão/fisiopatologia , Hipertrofia Ventricular Esquerda/prevenção & controle , Masculino , Proteínas Musculares/agonistas , Proteínas Musculares/genética , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/patologia , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Proteínas Ligases SKP Culina F-Box/genética , Transdução de Sinais/efeitos dos fármacos , Proteínas com Motivo Tripartido , Ubiquitina-Proteína Ligases/genética , Regulação para Cima/efeitos dos fármacos
16.
J Cardiovasc Pharmacol ; 62(5): 445-51, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23921314

RESUMO

Cardiomyocyte necrosis with attendant microscopic scarring is a pathological feature of human hypertensive heart disease (HHD). Understanding the pathophysiological origins of necrosis is integral to its prevention. In a rat model of HHD associated with aldosterone/salt treatment (ALDOST), myocyte necrosis is attributable to oxidative stress induced by cytosolic-free [Ca]i and mitochondrial [Ca]m overloading in which the rate of reactive oxygen species generation overwhelms their rate of detoxification by endogenous Zn-based antioxidant defenses. We hypothesized that nebivolol (Neb), unlike another ß1 adrenergic receptor antagonist atenolol (Aten), would have a multifaceted antioxidant potential based on its dual property as a ß3 receptor agonist, which activates endothelial nitric oxide synthase to stimulate nitric oxide (NO) generation. NO promotes the release of cytosolic Zn sequestered inactive by its binding protein, metallothionein. Given the reciprocal regulation between these cations, increased [Zn]i reduces Ca entry and attendant rise in [Ca]i and [Ca]m. Herein, we examined the antioxidant and cardioprotectant properties of Neb and Aten in rats receiving 4 weeks ALDOST. Compared with untreated age-/sex-matched controls, ALDOST alone or ALDOST with Aten, Neb cotreatment induced endothelial nitric oxide synthase activation, NO generation and a marked increase in [Zn]i with associated decline in [Ca]i and [Ca]m. Attendant antioxidant profile at subcellular and cellular levels included attenuation of mitochondrial H2O2 production and lipid peroxidation expressed as reduced 8-isoprostane concentrations in both mitochondria and cardiac tissue. Myocyte salvage was expressed as reduced microscopic scarring and tissue collagen volume fraction. Neb is a multifaceted antioxidant with unique properties as cardioprotectant in HHD.


Assuntos
Antioxidantes/farmacologia , Benzopiranos/farmacologia , Cardiotônicos/farmacologia , Etanolaminas/farmacologia , Hipertensão/tratamento farmacológico , Aldosterona/farmacologia , Animais , Cálcio/metabolismo , Citosol/efeitos dos fármacos , Citosol/metabolismo , Modelos Animais de Doenças , Humanos , Peróxido de Hidrogênio/metabolismo , Hipertensão/fisiopatologia , Mitocôndrias Cardíacas/efeitos dos fármacos , Mitocôndrias Cardíacas/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Nebivolol , Necrose/patologia , Óxido Nítrico/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Zinco/metabolismo
17.
Cardiovasc Drugs Ther ; 27(2): 161-70, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22373564

RESUMO

Aldosteronism, or chronic elevation in plasma aldosterone (ALDO) (inappropriate for dietary Na(+) intake), is accompanied by an adverse structural remodeling of the heart and vasculature. Herein, we bring forward a new perspective in which parathyroid hormone (PTH) is identified as a crucial mediator of pathologic cardiac remodeling in aldosteronism. Secondary hyperparathyroidism (SHPT) appears because of the marked urinary and fecal losses of Ca(2+) and Mg(2+) that accompany aldosteronism which creates ionized hypocalcemia and hypomagnesemia, providing major stimuli to the parathyroids' enhanced secretion of PTH. Invoked to restore extracellular Ca(2+) and Mg(2+) homeostasis, elevations in plasma PTH lead to paradoxical intracellular Ca(2+) overloading of diverse tissues. In the case of cardiomyocytes, the excessive intracellular Ca(2+) accumulation involves both cytosolic free and mitochondrial domains with a consequent induction of oxidative stress by these organelles and lost ATP synthesis. The ensuing opening of their inner membrane permeability transition pore (mPTP) accounts for the osmotic swelling and structural degeneration of mitochondria followed by programed cell necrosis. Tissue repair, invoked to preserve the structural integrity of myocardium accounts for a replacement fibrosis, or scarring, which is found scattered throughout the right and left heart; it represents a morphologic footprint of earlier necrosis. Multiple lines of evidence are reviewed that substantiate the PTH-mediated paradigm and the mitochondriocentric signal-transducer-effector pathway to cardiomyocyte necrosis.


Assuntos
Hiperaldosteronismo/metabolismo , Hormônio Paratireóideo/metabolismo , Remodelação Ventricular/fisiologia , Aldosterona/metabolismo , Animais , Humanos , Hiperaldosteronismo/patologia
18.
Curr Heart Fail Rep ; 10(1): 36-45, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23114591

RESUMO

The symptoms and signs constituting the congestive heart failure (CHF) syndrome have their pathophysiologic origins rooted in a salt-avid renal state mediated by effector hormones of the renin-angiotensin-aldosterone and adrenergic nervous systems. Controlled clinical trials, conducted over the past decade in patients having minimally to markedly severe symptomatic heart failure, have demonstrated the efficacy of a pharmacologic regimen that interferes with these hormones, including aldosterone receptor binding with either spironolactone or eplerenone. Potential pathophysiologic mechanisms, which have not hitherto been considered involved for the salutary responses and cardioprotection provided by these mineralocorticoid receptor antagonists, are reviewed herein. In particular, we focus on the less well-recognized impact of catecholamines and aldosterone on monovalent and divalent cation dyshomeostasis, which leads to hypokalemia, hypomagnesemia, ionized hypocalcemia with secondary hyperparathyroidism and hypozincemia. Attendant adverse cardiac consequences include a delay in myocardial repolarization with increased propensity for supraventricular and ventricular arrhythmias, and compromised antioxidant defenses with increased susceptibility to nonischemic cardiomyocyte necrosis.


Assuntos
Cardiotônicos/uso terapêutico , Insuficiência Cardíaca/tratamento farmacológico , Antagonistas de Receptores de Mineralocorticoides/uso terapêutico , Antioxidantes/fisiologia , Insuficiência Cardíaca/fisiopatologia , Humanos , Neurotransmissores/fisiologia , Estresse Oxidativo/fisiologia , Zinco/fisiologia
19.
Nat Rev Cardiol ; 10(1): 15-26, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23207731

RESUMO

The syncytium of cardiomyocytes in the heart is tethered within a matrix composed principally of type I fibrillar collagen. The matrix has diverse mechanical functions that ensure the optimal contractile efficiency of this muscular pump. In the diseased heart, cardiomyocytes are lost to necrotic cell death, and phenotypically transformed fibroblast-like cells-termed 'myofibroblasts'-are activated to initiate a 'reparative' fibrosis. The structural integrity of the myocardium is preserved by this scar tissue, although at the expense of its remodelled architecture, which has increased tissue stiffness and propensity to arrhythmias. A persisting population of activated myofibroblasts turns this fibrous tissue into a living 'secretome' that generates angiotensin II and its type 1 receptor, and fibrogenic growth factors (such as transforming growth factor-ß), all of which collectively act as a signal-transducer-effector signalling pathway to type I collagen synthesis and, therefore, fibrosis. Persistent myofibroblasts, and the resultant fibrous tissue they produce, cause progressive adverse myocardial remodelling, a pathological hallmark of the failing heart irrespective of its etiologic origin. Herein, we review relevant cellular, subcellular, and molecular mechanisms integral to cardiac fibrosis and consequent remodelling of atria and ventricles with a heterogeneity in cardiomyocyte size. Signalling pathways that antagonize collagen fibrillogenesis provide novel strategies for cardioprotection.


Assuntos
Cardiopatias/patologia , Ventrículos do Coração/patologia , Miócitos Cardíacos/patologia , Miofibroblastos/patologia , Remodelação Ventricular , Animais , Morte Celular , Colágeno/efeitos dos fármacos , Colágeno/metabolismo , Matriz Extracelular/metabolismo , Matriz Extracelular/patologia , Fibrose , Cardiopatias/tratamento farmacológico , Cardiopatias/metabolismo , Cardiopatias/fisiopatologia , Ventrículos do Coração/efeitos dos fármacos , Ventrículos do Coração/metabolismo , Ventrículos do Coração/fisiopatologia , Humanos , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Miofibroblastos/efeitos dos fármacos , Miofibroblastos/metabolismo , Necrose , Fenótipo , Transdução de Sinais
20.
Am J Med Sci ; 346(3): 194-8, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23187300

RESUMO

BACKGROUND: Idiopathic intracranial hypertension (IIH) is a syndrome consisting of headache, visual field defects and papilledema of uncertain etiology. The prospect was raised previously as to an association between aldosteronism and increased intracranial pressure in 2 middle-aged women with IIH and primary aldosteronism (PAL). Since then, 2 additional adults were identified and 2 other cases were reported from the United Kingdom, whereas 6 cases of IIH and secondary aldosteronism (SAL) in children have been reported in the English literature worldwide. METHODS: A retrospective analysis of cases from author institutions and published literature comparing clinical features, laboratory findings and therapeutic interventions in these 12 cases. RESULTS: The female-to-male ratio was 10:2. The mean age of the PAL patients was 49 ± 3 years-all hypertensive, with adrenal pathology in most. The mean age of the SAL patients was 11 ± 2 years-mostly normotensive, with 3 having Bartter's and 2 Gitelman syndromes, and 1 renal congenital hypoplasia. Plasma aldosterone levels were elevated (31 ± 5 ng/dL) in PAL and SAL, whereas plasma renin activity was suppressed in PAL. Hypokalemia (3.2 ± 0.2 mmol/L), hypomagnesemia (1.6 ± 0.3 mg/dL) and a putative metabolic alkalosis (serum HCO3 30 ± 1 mmol/L) were observed. IIH symptoms were controlled by spironolactone in 5, amiloride in 1, correction of hypokalemia and hypomagnesemia in 2, discontinuation of nonsteroidal anti-inflammatory drugs in 2, and reduction of body weight in 1. One patient required serial lumbar punctures, 2 a ventriculoperitoneal shunt, whereas all 3 patients with adrenal adenoma underwent surgical resection. CONCLUSIONS: An association between IIH and PAL occurs in hypertensive middle-aged women, whereas normotensive girls having an inherited renal tubular defect may have IIH with SAL. Patients with IIH should be evaluated for aldosteronism and considered for spironolactone therapy.


Assuntos
Hiperaldosteronismo/complicações , Pseudotumor Cerebral/etiologia , Adolescente , Adulto , Aldosterona/sangue , Criança , Eletrólitos/sangue , Feminino , Humanos , Hiperaldosteronismo/sangue , Hiperaldosteronismo/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Antagonistas de Receptores de Mineralocorticoides/uso terapêutico , Pseudotumor Cerebral/sangue , Renina/sangue , Espironolactona/uso terapêutico
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