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1.
Br J Haematol ; 199(4): 520-528, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36041779

RESUMO

We investigated antibody and coronavirus disease 2019 (COVID-19)-specific T-cell mediated responses via ultra-deep immunosequencing of the T-cell receptor (TCR) repertoire in patients with plasma cell dyscrasias (PCD). We identified 364 patients with PCD who underwent spike antibody testing using commercially available spike-receptor binding domain immunoglobulin G antibodies ≥2 weeks after completion of the initial two doses of mRNA vaccines or one dose of JNJ-78436735. A total of 56 patients underwent TCR immunosequencing after vaccination. Overall, 86% tested within 6 months of vaccination had detectable spike antibodies. Increasing age, use of anti-CD38 or anti-B-cell maturation antigen therapy, and receipt of BNT162b2 (vs. mRNA-1273) were associated with lower antibody titres. We observed an increased proportion of TCRs associated with surface glycoprotein regions of the COVID-19 genome after vaccination, consistent with spike-specific T-cell responses. The median spike-specific T-cell breadth was 3.11 × 10-5 , comparable to those in healthy populations after vaccination. Although spike-specific T-cell breadth correlated with antibody titres, patients without antibody responses also demonstrated spike-specific T-cell responses. Patients receiving mRNA-1273 had higher median spike-specific T-cell breadth than those receiving BNT162b2 (p = 0.01). Although patients with PCD are often immunocompromised due to underlying disease and treatments, COVID-19 vaccination can still elicit humoral and T-cell responses and remain an important intervention in this patient population.


Assuntos
COVID-19 , Paraproteinemias , Humanos , COVID-19/prevenção & controle , Linfócitos T , Vacinas contra COVID-19 , Ad26COVS1 , Vacina BNT162 , Vacinação , Anticorpos , Receptores de Antígenos de Linfócitos T , Anticorpos Antivirais
2.
Clin Sci (Lond) ; 136(8): 599-620, 2022 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-35452099

RESUMO

High-salt diets are a major cause of hypertension and cardiovascular (CV) disease. Many governments are interested in using food salt reduction programs to reduce the risk for salt-induced increases in blood pressure and CV events. It is assumed that reducing the salt concentration of processed foods will substantially reduce mean salt intake in the general population. However, contrary to expectations, reducing the sodium density of nearly all foods consumed in England by 21% had little or no effect on salt intake in the general population. This may be due to the fact that in England, as in other countries including the U.S.A., mean salt intake is already close to the lower normal physiologic limit for mean salt intake of free-living populations. Thus, mechanism-based strategies for preventing salt-induced increases in blood pressure that do not solely depend on reducing salt intake merit attention. It is now recognized that the initiation of salt-induced increases in blood pressure often involves a combination of normal increases in sodium balance, blood volume and cardiac output together with abnormal vascular resistance responses to increased salt intake. Therefore, preventing either the normal increases in sodium balance and cardiac output, or the abnormal vascular resistance responses to salt, can prevent salt-induced increases in blood pressure. Suboptimal nutrient intake is a common cause of the hemodynamic disturbances mediating salt-induced hypertension. Accordingly, efforts to identify and correct the nutrient deficiencies that promote salt sensitivity hold promise for decreasing population risk of salt-induced hypertension without requiring reductions in salt intake.


Assuntos
Doenças Cardiovasculares , Hipertensão , Pressão Sanguínea , Humanos , Hipertensão/induzido quimicamente , Hipertensão/prevenção & controle , Sódio , Cloreto de Sódio na Dieta/efeitos adversos
3.
Am J Emerg Med ; 54: 81-86, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35144108

RESUMO

BACKGROUND: Emergency department (ED) workers have an increased seroprevalence of SARS-CoV-2 antibodies. However, breakthrough infections in ED workers have led to a reduced workforce within a strained healthcare system. By measuring levels of IgG antibodies to the SARS-CoV-2 nucleocapsid and spike antigens in ED workers, we determined the incidence of infection and described the course of antibody levels. We also measured the antibody response to vaccination and examined factors associated with immunogenicity. METHODS: We conducted a prospective cohort study of ED workers conducted at a single ED from September 2020-April 2021. IgG antibodies to the SARS-CoV-2 nucleocapsid antigen were measured at baseline, 3, and 6 months, and IgG antibodies to the SARS-CoV-2 spike antigen were measured at 6 months. RESULTS: At baseline, we found 5 out of 139 (3.6%) participants with prior infection. At 6 months, 4 of the 5 had antibody results below the test manufacturer's positivity threshold. We identified one incident case of SARS-COV-2 infection out of 130 seronegative participants (0.8%, 95% CI 0.02-4.2%). In 131 vaccinated participants (125 BNT162b2, 6 mRNA-1273), 131 tested positive for anti-spike antibodies. We identified predictors of anti-spike antibody levels: time since vaccination, prior COVID-19 infection, age, and vaccine type. Each additional week since vaccination was associated with an 11.1% decrease in anti-spike antibody levels. (95% CI 6.2-15.8%). CONCLUSION: ED workers experienced a low incidence of SARS-CoV-2 infection and developed antibodies in response to vaccines and prior infection. Antibody levels decreased markedly with time since infection or vaccination.


Assuntos
COVID-19 , SARS-CoV-2 , Anticorpos Antivirais , Vacina BNT162 , COVID-19/epidemiologia , Serviço Hospitalar de Emergência , Pessoal de Saúde , Humanos , Nucleocapsídeo , Estudos Prospectivos , Estudos Soroepidemiológicos , Glicoproteína da Espícula de Coronavírus
4.
Am J Physiol Heart Circ Physiol ; 320(5): H1903-H1918, 2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-33797275

RESUMO

On average, black individuals are widely believed to be more sensitive than white individuals to blood pressure (BP) effects of changes in salt intake. However, few studies have directly compared the BP effects of changing salt intake in black versus white individuals. In this narrative review, we analyze those studies and note that when potassium intake substantially exceeds the recently recommended US dietary goal of 87 mmol/day, black adults do not appear more sensitive than white adults to BP effects of short-term or long-term increases in salt intake (from an intake ≤50 mmol/day up to 150 mmol/day or more). However, with lower potassium intakes, racial differences in salt sensitivity are observed. Mechanistic studies suggest that racial differences in salt sensitivity are related to differences in vascular resistance responses to changes in salt intake mediated by vasodilator and vasoconstrictor pathways. With respect to cause and prevention of racial disparities in salt sensitivity, it is noteworthy that 1) on average, black individuals consume less potassium than white individuals and 2) consuming supplemental potassium bicarbonate, or potassium rich foods can prevent racial disparities in salt sensitivity. However, the new US dietary guidelines reduced the dietary potassium goal well below the amount associated with preventing racial disparities in salt sensitivity. These observations should motivate research on the impact of the new dietary potassium guidelines on racial disparities in salt sensitivity, the risks and benefits of potassium-containing salt substitutes or supplements, and methods for increasing consumption of foods rich in nutrients that protect against salt-induced hypertension.


Assuntos
Pressão Sanguínea/fisiologia , Hipertensão/fisiopatologia , Potássio na Dieta , Sódio na Dieta , População Negra , Humanos , Fatores de Risco , População Branca
5.
J Med Internet Res ; 21(7): e14160, 2019 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-31271154

RESUMO

BACKGROUND: Simulators used in teaching are interactive applications comprising a mathematical model of the system under study and a graphical user interface (GUI) that allows the user to control the model inputs and visualize the model results in an intuitive and educational way. Well-designed simulators promote active learning, enhance problem-solving skills, and encourage collaboration and small group discussion. However, creating simulators for teaching purposes is a challenging process that requires many contributors including educators, modelers, graphic designers, and programmers. The availability of a toolchain of user-friendly software tools for building simulators can facilitate this complex task. OBJECTIVE: This paper aimed to describe an open-source software toolchain termed Bodylight.js that facilitates the creation of browser-based client-side simulators for teaching purposes, which are platform independent, do not require any installation, and can work offline. The toolchain interconnects state-of-the-art modeling tools with current Web technologies and is designed to be resilient to future changes in the software ecosystem. METHODS: We used several open-source Web technologies, namely, WebAssembly and JavaScript, combined with the power of the Modelica modeling language and deployed them on the internet with interactive animations built using Adobe Animate. RESULTS: Models are implemented in the Modelica language using either OpenModelica or Dassault Systèmes Dymola and exported to a standardized Functional Mock-up Unit (FMU) to ensure future compatibility. The C code from the FMU is further compiled to WebAssembly using Emscripten. Industry-standard Adobe Animate is used to create interactive animations. A new tool called Bodylight.js Composer was developed for the toolchain that enables one to create the final simulator by composing the GUI using animations, plots, and control elements in a drag-and-drop style and binding them to the model variables. The resulting simulators are stand-alone HyperText Markup Language files including JavaScript and WebAssembly. Several simulators for physiology education were created using the Bodylight.js toolchain and have been received with general acclaim by teachers and students alike, thus validating our approach. The Nephron, Circulation, and Pressure-Volume Loop simulators are presented in this paper. Bodylight.js is licensed under General Public License 3.0 and is free for anyone to use. CONCLUSIONS: Bodylight.js enables us to effectively develop teaching simulators. Armed with this technology, we intend to focus on the development of new simulators and interactive textbooks for medical education. Bodylight.js usage is not limited to developing simulators for medical education and can facilitate the development of simulators for teaching complex topics in a variety of different fields.


Assuntos
Educação Médica/métodos , Software/normas , Interface Usuário-Computador , Humanos , Internet
6.
Curr Opin Nephrol Hypertens ; 27(2): 83-92, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29278541

RESUMO

PURPOSE OF REVIEW: For decades, it has been widely accepted that initiation of salt-induced hypertension involves a type of kidney dysfunction (natriuretic handicap), which causes salt-sensitive subjects to initially excrete less of a sodium load than normal subjects and undergo abnormal increases in cardiac output, and therefore blood pressure. Here we discuss emerging views that renal vasodysfunction, not natriuretic dysfunction (subnormal sodium excretion), is usually a critical factor initiating salt-induced hypertension. RECENT FINDINGS: Serious logical issues have been raised with arguments supporting historical views that natriuretic dysfunction initiates hypertension in response to increased salt intake. Most salt-sensitive humans do not have a 'natriuretic handicap' causing them to excrete a sodium load more slowly and retain more of it than salt-resistant normal subjects. Mounting evidence indicates that in most salt-sensitive subjects, renal vasodysfunction, defined as impaired renal vasodilation and abnormally increased renal vascular resistance in response to increased salt intake, in the absence of greater sodium retention than in salt-loaded normal subjects, is involved in initiation of salt-induced hypertension. SUMMARY: To advance discovery, prevention, and treatment of primary abnormalities causing salt-induced hypertension, greater research emphasis should be placed on identifying mechanisms mediating subnormal renal vasodilation and abnormally increased renal vascular resistance in response to high-salt diets.


Assuntos
Hipertensão/etiologia , Hipertensão/fisiopatologia , Rim/fisiopatologia , Cloreto de Sódio na Dieta/metabolismo , Resistência Vascular , Vasodilatação , Animais , Pressão Sanguínea , Humanos , Rim/irrigação sanguínea , Cloreto de Sódio na Dieta/efeitos adversos
7.
J Biol Chem ; 291(14): 7754-66, 2016 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-26841864

RESUMO

The NRF2 (also known as NFE2L2) transcription factor is a critical regulator of genes involved in defense against oxidative stress. Previous studies suggest thatNrf2plays a role in adipogenesisin vitro, and deletion of theNrf2gene protects against diet-induced obesity in mice. Here, we demonstrate that resistance to diet-induced obesity inNrf2(-/-)mice is associated with a 20-30% increase in energy expenditure. Analysis of bioenergetics revealed thatNrf2(-/-)white adipose tissues exhibit greater oxygen consumption. White adipose tissue showed a >2-fold increase inUcp1gene expression. Oxygen consumption is also increased nearly 2.5-fold inNrf2-deficient fibroblasts. Oxidative stress induced by glucose oxidase resulted in increasedUcp1expression. Conversely, antioxidant chemicals (such asN-acetylcysteine and Mn(III)tetrakis(4-benzoic acid)porphyrin chloride) and SB203580 (a known suppressor ofUcp1expression) decreasedUcp1and oxygen consumption inNrf2-deficient fibroblasts. These findings suggest that increasing oxidative stress by limitingNrf2function in white adipocytes may be a novel means to modulate energy balance as a treatment of obesity and related clinical disorders.


Assuntos
Adipogenia , Regulação da Expressão Gênica , Canais Iônicos/biossíntese , Proteínas Mitocondriais/biossíntese , Fator 2 Relacionado a NF-E2/deficiência , Obesidade/metabolismo , Estresse Oxidativo , Animais , Dieta/efeitos adversos , Fibroblastos/metabolismo , Fibroblastos/patologia , Sequestradores de Radicais Livres/farmacologia , Canais Iônicos/genética , Camundongos , Camundongos Knockout , Proteínas Mitocondriais/genética , Obesidade/induzido quimicamente , Obesidade/genética , Obesidade/patologia , Consumo de Oxigênio/efeitos dos fármacos , Proteína Desacopladora 1
8.
Kidney Int ; 90(5): 965-973, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27546606

RESUMO

It is widely held that in response to high salt diets, normal individuals are acutely and chronically resistant to salt-induced hypertension because they rapidly excrete salt and retain little of it so that their blood volume, and therefore blood pressure, does not increase. Conversely, it is also widely held that salt-sensitive individuals develop salt-induced hypertension because of an impaired renal capacity to excrete salt that causes greater salt retention and blood volume expansion than that which occurs in normal salt-resistant individuals. Here we review results of both acute and chronic salt-loading studies that have compared salt-induced changes in sodium retention and blood volume between normal subjects (salt-resistant normotensive control subjects) and salt-sensitive subjects. The results of properly controlled studies strongly support an alternative view: during acute or chronic increases in salt intake, normal salt-resistant subjects undergo substantial salt retention and do not excrete salt more rapidly, retain less sodium, or undergo lesser blood volume expansion than do salt-sensitive subjects. These observations: (i) directly conflict with the widely held view that renal excretion of sodium accounts for resistance to salt-induced hypertension, and (ii) have implications for contemporary understanding of how various genetic, immunologic, and other factors determine acute and chronic blood pressure responses to high salt diets.


Assuntos
Volume Sanguíneo/efeitos dos fármacos , Hipertensão/etiologia , Cloreto de Sódio na Dieta/efeitos adversos , Cloreto de Sódio na Dieta/metabolismo , Estudos de Casos e Controles , Humanos , Sódio/metabolismo , Cloreto de Sódio na Dieta/farmacologia
9.
FASEB J ; 29(8): 3342-56, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25877213

RESUMO

The angiotensin II type 1 receptor (AT1) is a 7-transmembrane domain GPCR that when activated by its ligand angiotensin II, generates signaling events promoting vascular dysfunction and the development of cardiovascular disease. Here, we show that the single-transmembrane oxidized LDL (oxLDL) receptor (LOX-1) resides in proximity to AT1 on cell-surface membranes and that binding of oxLDL to LOX-1 can allosterically activate AT1-dependent signaling events. oxLDL-induced signaling events in human vascular endothelial cells were abolished by knockdown of AT1 and inhibited by AT1 blockade (ARB). oxLDL increased cytosolic G protein by 350% in Chinese hamster ovary (CHO) cells with genetically induced expression of AT1 and LOX-1, whereas little increase was observed in CHO cells expressing only LOX-1. Immunoprecipitation and in situ proximity ligation assay (PLA) assays in CHO cells revealed the presence of cell-surface complexes involving LOX-1 and AT1. Chimeric analysis showed that oxLDL-induced AT1 signaling events are mediated via interactions between the intracellular domain of LOX-1 and AT1 that activate AT1. oxLDL-induced impairment of endothelium-dependent vascular relaxation of vascular ring from mouse thoracic aorta was abolished by ARB or genetic deletion of AT1. These findings reveal a novel pathway for AT1 activation and suggest a new mechanism whereby oxLDL may be promoting risk for cardiovascular disease.


Assuntos
Lectinas/metabolismo , Lipoproteínas LDL/metabolismo , Receptor Tipo 1 de Angiotensina/metabolismo , Receptores de LDL Oxidado/metabolismo , Animais , Células CHO , Células COS , Linhagem Celular , Linhagem Celular Tumoral , Chlorocebus aethiops , Cricetulus , Células Endoteliais/metabolismo , Endotélio Vascular/metabolismo , Humanos , Transdução de Sinais/fisiologia
11.
Physiol Genomics ; 46(18): 671-8, 2014 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-25073601

RESUMO

Common inbred strains of the laboratory rat can be divided into four major mitochondrial DNA (mtDNA) haplotype groups represented by the BN, F344, LEW, and SHR strains. In the current study, we investigated the metabolic and hemodynamic effects of the SHR vs. F344 mtDNA by comparing the SHR vs. SHR-mt(F344) conplastic strains that are genetically identical except for their mitochondrial genomes. Altogether 13 amino acid substitutions in protein coding genes, seven single nucleotide polymorphisms in tRNA genes, and 12 single nucleotide changes in rRNA genes were detected in F344 mtDNA compared with SHR mtDNA. Analysis of oxidative phosphorylation system (OXPHOS) in heart left ventricles (LV), muscle, and liver revealed reduced activity and content of several respiratory chain complexes in SHR-mt(F344) conplastic rats compared with the SHR strain. Lower function of OXPHOS in LV of conplastic rats was associated with significantly increased relative ventricular mass and reduced fractional shortening that was independent of blood pressure. In addition, conplastic rats exhibited reduced sensitivity of skeletal muscles to insulin action and impaired glucose tolerance. These results provide evidence that inherited alterations in mitochondrial genome, in the absence of variation in the nuclear genome and other confounding factors, predispose to insulin resistance, cardiac hypertrophy and systolic dysfunction.


Assuntos
Cardiomegalia/genética , Cardiomegalia/fisiopatologia , DNA Mitocondrial/genética , Resistência à Insulina/genética , Fosforilação Oxidativa , Sístole , Nucleotídeos de Adenina/metabolismo , Animais , Sequência de Bases , Pressão Sanguínea/efeitos dos fármacos , Eletrocardiografia , Transporte de Elétrons/efeitos dos fármacos , Dosagem de Genes , Genes Mitocondriais , Glucose/metabolismo , Teste de Tolerância a Glucose , Haplótipos/genética , Insulina/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Masculino , Dados de Sequência Molecular , Tamanho do Órgão/efeitos dos fármacos , Fosforilação Oxidativa/efeitos dos fármacos , Fenótipo , RNA de Transferência/genética , Ratos Endogâmicos F344 , Ratos Endogâmicos SHR , Análise de Sequência de DNA , Sístole/efeitos dos fármacos , Função Ventricular Esquerda/efeitos dos fármacos
12.
Nat Genet ; 37(3): 243-53, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15711544

RESUMO

Integration of genome-wide expression profiling with linkage analysis is a new approach to identifying genes underlying complex traits. We applied this approach to the regulation of gene expression in the BXH/HXB panel of rat recombinant inbred strains, one of the largest available rodent recombinant inbred panels and a leading resource for genetic analysis of the highly prevalent metabolic syndrome. In two tissues important to the pathogenesis of the metabolic syndrome, we mapped cis- and trans-regulatory control elements for expression of thousands of genes across the genome. Many of the most highly linked expression quantitative trait loci are regulated in cis, are inherited essentially as monogenic traits and are good candidate genes for previously mapped physiological quantitative trait loci in the rat. By comparative mapping we generated a data set of 73 candidate genes for hypertension that merit testing in human populations. Mining of this publicly available data set is expected to lead to new insights into the genes and regulatory pathways underlying the extensive range of metabolic and cardiovascular disease phenotypes that segregate in these recombinant inbred strains.


Assuntos
Perfilação da Expressão Gênica , Transcrição Gênica , Animais , Pressão Sanguínea/genética , Ligação Genética , Locos de Características Quantitativas , Ratos , Recombinação Genética
13.
Hypertension ; 80(5): 1077-1091, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37043613

RESUMO

BACKGROUND: Few studies have investigated the hemodynamic mechanism whereby primary aldosteronism causes hypertension. The traditional view holds that hyperaldosteronism initiates hypertension by amplifying salt-dependent increases in cardiac output (CO) by promoting increases in sodium retention and blood volume. Systemic vascular resistance (SVR) is said to increase only as a secondary consequence of the increased CO and blood pressure. However, mounting evidence indicates that aldosterone can influence multiple pathways regulating vascular tone. We investigated the primary hemodynamic mechanism whereby hyperaldosteronism promotes salt sensitivity and initiation of salt-dependent hypertension. METHODS: In unilaterally nephrectomized male Sprague-Dawley rats given infusions of aldosterone or vehicle, we used chronically implanted arterial pressure probes and Doppler ultrasonic flow probes to continuously monitor changes in mean arterial pressure, CO, and SVR 24 hours/day, 7 days/week in response to increases in salt intake. RESULTS: In vehicle-treated control rats, switching from a low-salt diet to a high-salt diet initiated modest increases in mean arterial pressure by increasing SVR while simultaneously decreasing heart rate and CO. In aldosterone-treated rats compared with control rats, switching from a low-salt diet to a high-salt diet initiated significantly greater increases in mean arterial pressure and SVR and significantly greater decreases in heart rate and CO. CONCLUSIONS: Aldosterone promoted salt sensitivity and initiation of salt-dependent hypertension by amplifying salt-induced increases in SVR while decreasing CO. Increases in CO are not required for the initiation or maintenance of hypertension. These findings challenge the traditional view of the hemodynamic mechanisms that cause hypertension in primary aldosteronism.


Assuntos
Hiperaldosteronismo , Hipertensão , Masculino , Ratos , Animais , Aldosterona , Cloreto de Sódio na Dieta/efeitos adversos , Ratos Sprague-Dawley , Hemodinâmica , Pressão Sanguínea , Débito Cardíaco , Resistência Vascular , Hiperaldosteronismo/complicações
14.
Physiol Genomics ; 44(9): 487-94, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-22414913

RESUMO

Common inbred strains of the laboratory rat can be divided into four different mitochondrial DNA haplotype groups represented by the SHR, BN, LEW, and F344 strains. In the current study, we investigated the metabolic and hemodynamic effects of the SHR vs. LEW mitochondrial genomes by comparing the SHR to a new SHR conplastic strain, SHR-mt(LEW); these strains are genetically identical except for their mitochondrial genomes. Complete mitochondrial DNA (mtDNA) sequence analysis comparing the SHR and LEW strains revealed gene variants encoding amino acid substitutions limited to a single mitochondrial enzyme complex, NADH dehydrogenase (complex I), affecting subunits 2, 4, and 5. Two of the variants in the mt-Nd4 subunit gene are located close to variants known to be associated with exercise intolerance and diabetes mellitus in humans. No variants were found in tRNA or rRNA genes. These variants in mt-Nd2, mt-Nd4, and mt-Nd5 in the SHR-mt(LEW) conplastic strain were linked to reductions in oxidative and nonoxidative glucose metabolism in skeletal muscle. In addition, SHR-mt(LEW) conplastic rats showed increased serum nonesterified fatty acid levels and resistance to insulin stimulated incorporation of glucose into adipose tissue lipids. These results provide evidence that inherited variation in mitochondrial genes encoding respiratory chain complex I subunits, in the absence of variation in the nuclear genome and other confounding factors, can influence glucose and lipid metabolism when expressed on the nuclear genetic background of the SHR strain.


Assuntos
DNA Mitocondrial/genética , Variação Genética , Hipertensão/genética , Resistência à Insulina/genética , NADH Desidrogenase/genética , Fosforilação Oxidativa , Nucleotídeos de Adenina/metabolismo , Tecido Adiposo/enzimologia , Sequência de Aminoácidos , Animais , Glicemia/metabolismo , Pressão Sanguínea , Carboidratos da Dieta/administração & dosagem , Carboidratos da Dieta/metabolismo , Modelos Animais de Doenças , Ácidos Graxos não Esterificados/sangue , Frutose/administração & dosagem , Frutose/metabolismo , Haplótipos , Frequência Cardíaca , Hereditariedade , Hipertensão/sangue , Hipertensão/enzimologia , Hipertensão/fisiopatologia , Insulina/sangue , Dados de Sequência Molecular , Músculo Esquelético/enzimologia , NADH Desidrogenase/metabolismo , Fenótipo , Ratos , Ratos Endogâmicos BN , Ratos Endogâmicos F344 , Ratos Endogâmicos Lew , Ratos Endogâmicos SHR
15.
Physiol Genomics ; 44(2): 173-82, 2012 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-22128087

RESUMO

CD36 fatty acid translocase plays a key role in supplying heart with its major energy substrate, long-chain fatty acids (FA). Previously, we found that the spontaneously hypertensive rat (SHR) harbors a deletion variant of Cd36 gene that results in reduced transport of long-chain FA into cardiomyocytes and predisposes the SHR to cardiac hypertrophy. In the current study, we analyzed the effects of mutant Cd36 on susceptibility to ischemic ventricular arrhythmias and myocardial infarction in adult SHR-Cd36 transgenic rats with wild-type Cd36 compared with age-matched SHR controls. Using an open-chest model of coronary artery occlusion, we found that SHR-Cd36 transgenic rats showed profound arrhythmogenesis resulting in significantly increased duration of tachyarrhythmias (207 ± 48 s vs. 55 ± 21 s, P < 0.05), total number of premature ventricular complexes (2,623 ± 517 vs. 849 ± 250, P < 0.05) and arrhythmia score (3.86 ± 0.18 vs. 3.13 ± 0.13, P < 0.001). On the other hand, transgenic SHR compared with SHR controls showed significantly reduced infarct size (52.6 ± 4.3% vs. 72.4 ± 2.9% of area at risk, P < 0.001). Similar differences were observed in isolated perfused hearts, and the increased susceptibility of transgenic SHR to arrhythmias was abolished by reserpine, suggesting the involvement of catecholamines. To further search for possible molecular mechanisms of altered ischemic tolerance, we compared gene expression profiles in left ventricles dissected from 6-wk-old transgenic SHR vs. age-matched controls using Illumina-based sequencing. Circadian rhythms and oxidative phosphorylation were identified as the top KEGG pathways, while circadian rhythms, VDR/RXR activation, IGF1 signaling, and HMGB1 signaling were the top IPA canonical pathways potentially important for Cd36-mediated effects on ischemic tolerance. It can be concluded that transgenic expression of Cd36 plays an important role in modulating the incidence and severity of ischemic and reperfusion ventricular arrhythmias and myocardial infarct size induced by coronary artery occlusion. The proarrhythmic effect of Cd36 transgene appears to be dependent on adrenergic stimulation.


Assuntos
Arritmias Cardíacas/genética , Antígenos CD36/genética , Perfilação da Expressão Gênica , Infarto do Miocárdio/genética , Animais , Arritmias Cardíacas/metabolismo , Pressão Sanguínea , Antígenos CD36/metabolismo , Predisposição Genética para Doença , Masculino , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/patologia , Ratos , Ratos Endogâmicos SHR
19.
Physiol Genomics ; 43(7): 372-9, 2011 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-21285283

RESUMO

Increased circulating levels of resistin have been proposed as a possible link between obesity and insulin resistance; however, many of the potential metabolic effects of resistin remain to be investigated, including systemic versus local resistin action. We investigated potential autocrine effects of resistin on lipid and glucose metabolism in 2- and 16-mo-old transgenic spontaneously hypertensive rats (SHR) expressing a nonsecreted form of mouse resistin under control of the aP2 promoter. To search for possible molecular mechanisms, we compared gene expression profiles in adipose tissue in 6-wk-old transgenic SHR versus control rats, before development of insulin resistance, by digital transcriptional profiling using high-throughput sequencing. Both young and old transgenic rats showed moderate expression of the resistin transgene in adipose tissue but had serum resistin levels similar to control SHR and undetectable levels of transgenic resistin in the circulation. Young transgenic rats exhibited mild glucose intolerance. In contrast, older transgenic rats displayed marked glucose intolerance in association with near total resistance of adipose tissue to insulin-stimulated glucose incorporation into lipids (6 ± 2 vs. 77 ± 19 nmol glucose·g(-1)·2 h(-1), P < 0.00001). Ingenuity Pathway Analysis of differentially expressed genes revealed calcium signaling, Nuclear factor-erythroid 2-related factor-2 (NRF2)-mediated oxidative stress response, and actin cytoskeletal signaling canonical pathways as those most significantly affected. Analysis using DAVID software revealed oxidative phosphorylation, glutathione metabolism, pyruvate metabolism, and peroxisome proliferator-activated receptor (PPAR) signaling as top Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. These results suggest that with increasing age autocrine effects of resistin in fat tissue may predispose to diabetes in part by impairing insulin action in adipose tissue.


Assuntos
Tecido Adiposo/metabolismo , Envelhecimento/metabolismo , Perfilação da Expressão Gênica/métodos , Resistina/metabolismo , Envelhecimento/genética , Animais , Teste de Tolerância a Glucose , Resistência à Insulina/genética , Resistência à Insulina/fisiologia , Reação em Cadeia da Polimerase , Ratos , Ratos Endogâmicos SHR , Ratos Transgênicos , Resistina/genética
20.
J Biol Chem ; 285(12): 9292-300, 2010 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-20089859

RESUMO

Nuclear factor E2-related factor 2 (Nrf2) is a cap-n-collar basic leucine zipper (CNC-bZIP) transcription factor that is well established as a master regulator of phase II detoxification and antioxidant gene expression and is strongly expressed in tissues involved in xenobiotic metabolism including liver and kidney. Nrf2 is also abundantly expressed in adipose tissue; however, the exact function of Nrf2 in adipocyte biology is unclear. In the current study we show that targeted knock-out of Nrf2 in mice decreases adipose tissue mass, promotes formation of small adipocytes, and protects against weight gain and obesity otherwise induced by a high fat diet. In mouse embryonic fibroblasts, 3T3-L1 cells, and human subcutaneous preadipocytes, selective deficiency of Nrf2 impairs adipocyte differentiation. Deficiency of Nrf2 also leads to decreased expression of peroxisome proliferator-activated receptor gamma (PPARgamma), CCAAT enhancer-binding protein alpha (C/EBPalpha), and their downstream targets during adipocyte differentiation. Conversely, activation of Nrf2 in 3T3-L1 cells by stable knockdown of its negative regulator Keap1 enhances and accelerates hormone-induced adipocyte differentiation. Transfection of Nrf2 stimulates Ppargamma promoter activity, and stable knockdown of Keap1 enhances PPARgamma expression in 3T3-L1 cells. In addition, chromatin immunoprecipitation studies show that Nrf2 associates with consensus binding sites for Nrf2 in the Ppargamma promoter. These findings demonstrate a novel biologic role for Nrf2 beyond its participation in detoxification and antioxidant pathways and place Nrf2 within the limited network of transcription factors that control adipocyte differentiation by regulating expression of PPARgamma.


Assuntos
Adipócitos/metabolismo , Dieta , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/fisiologia , Obesidade/prevenção & controle , Células 3T3-L1 , Animais , Diferenciação Celular , Gorduras na Dieta/metabolismo , Fibroblastos/metabolismo , Regulação da Expressão Gênica , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Movimento , Regiões Promotoras Genéticas
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