Changes in glucose and glutamine lymphocyte metabolisms induced by type I interferon α.

In lymphocytes (LY), the well-documented antiproliferative effects of IFN-α are associated with inhibition of protein synthesis, decreased amino acid incorporation, and cell cycle arrest. However, the effects of this cytokine on the metabolism of glucose and glutamine in these cells have not been well investigated. Thus, mesenteric and spleen LY of male Wistar rats were cultured in the presence or absence of IFN-α, and the changes on glucose and glutamine metabolisms were investigated. The reduced proliferation of mesenteric LY was accompanied by a reduction in glucose total consumption (35%), aerobic glucose metabolism (55%), maximal activity of glucose-6-phosphate dehydrogenase (49%), citrate synthase activity (34%), total glutamine consumption (30%), aerobic glutamine consumption (20.3%) and glutaminase activity (56%). In LY isolated from spleen, IFNα also reduced the proliferation and impaired metabolism. These data demonstrate that in LY, the antiproliferative effects of IFNα are associated with a reduction in glucose and glutamine metabolisms.

Intracellular mechanisms of specific beta-adrenoceptor antagonists involved in improved cardiac function and survival in a genetic model of heart failure.

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.

Integrative effect of carvedilol and aerobic exercise training therapies on improving cardiac contractility and remodeling in heart failure mice.

The use of ß-blockers is mandatory for counteracting heart failure (HF)-induced chronic sympathetic hyperactivity, cardiac dysfunction and remodeling. Importantly, aerobic exercise training, an efficient nonpharmacological therapy to HF, also counteracts sympathetic hyperactivity in HF and improves exercise tolerance and cardiac contractility; the latter associated with changes in cardiac Ca(2+) handling. This study was undertaken to test whether combined ß-blocker and aerobic exercise training would integrate the beneficial effects of isolated therapies on cardiac structure, contractility and cardiomyocyte Ca(2+) handling in a genetic model of sympathetic hyperactivity-induced HF (α2A/α2C- adrenergic receptor knockout mice, KO). We used a cohort of 5-7 mo male wild-type (WT) and congenic mice (KO) with C57Bl6/J genetic background randomly assigned into 5 groups: control (WT), saline-treated KO (KOS), exercise trained KO (KOT), carvedilol-treated KO (KOC) and, combined carvedilol-treated and exercise-trained KO (KOCT). Isolated and combined therapies reduced mortality compared with KOS mice. Both KOT and KOCT groups had increased exercise tolerance, while groups receiving carvedilol had increased left ventricular fractional shortening and reduced cardiac collagen volume fraction compared with KOS group. Cellular data confirmed that cardiomyocytes from KOS mice displayed abnormal Ca(2+) handling. KOT group had increased intracellular peak of Ca(2+) transient and reduced diastolic Ca(2+) decay compared with KOS group, while KOC had increased Ca(2+) decay compared with KOS group. Notably, combined therapies re-established cardiomyocyte Ca(2+) transient paralleled by increased SERCA2 expression and SERCA2:PLN ratio toward WT levels. Aerobic exercise trained increased the phosphorylation of PLN at Ser(16) and Thr(17) residues in both KOT and KOCT groups, but carvedilol treatment reduced lipid peroxidation in KOC and KOCT groups compared with KOS group. The present findings provide evidence that the combination of carvedilol and aerobic exercise training therapies lead to a better integrative outcome than carvedilol or exercise training used in isolation.

Association of physical training with beta-blockers in heart failure in mice.

BACKGROUND: Currently there are several types of interventions for the treatment of heart failure (HF). Among these are beta-blocker therapy (BB) and physical training (PT). However, the effects of the combination of these therapies are poorly studied. OBJECTIVE: To investigate the effects of BB treatment with metoprolol (M) and carvedilol (C) associated with PT in mice with HF. METHODS: We used a genetic model of sympathetic hyperactivity-induced heart failure in mice. Initially, we divided the HF animals into three groups: sedentary (S); trained (T); treated with M (138 mg/kg) (M); or C (65 mg/kg) (C). In the second part, we divided the groups into three subgroups: sedentary (S); trained and treated with M (TM); and trained and treated with C (CT). The PT consisted of aerobic training on a treadmill for 8 weeks. Exercise tolerance was assessed by maximal graded test, and fractional shortening (FS) was assessed by echocardiography. Cardiomyocyte diameter and collagen volume fraction were evaluated by histological analysis. Data were compared by one way ANOVA and post hoc Duncan test. The significance level was set at p ≤ 0.05. RESULTS: As to FS and cardiac remodeling, we found that, in isolation, T, M, and C showed an improvement of the variables analyzed. As to therapy combination, after the intervention period, we observed an increase in exercise tolerance in MT and CT (43.0% and 33.0% respectively). There was also a reduction in cardiomyocyte diameter (10.0% and 9.0% respectively) and in collagen volume fraction (52.0% and 63.0%) after the intervention. However, only CT significantly improved FS. CONCLUSION: The association of PT with M or C therapies provided benefits on cardiac function and remodeling in HF mice.

Associação de betabloqueadores e treinamento físico na insuficiência cardíaca de camundongos / Association of physical training with beta-blockers in heart failure in mice / Asociación de betabloqueantes y entrenamiento físico en la insuficiencia cardíaca de ratones

FUNDAMENTO: O tratamento da insuficiência cardíaca (IC) conta atualmente com diversos tipos de intervenções. Dentre elas, destacam-se a terapia com betabloqueadores (BB) e o treinamento físico (TF). Contudo, os efeitos da associação dessas terapias são pouco estudados. OBJETIVO: Verificar os efeitos do tratamento com BB, metoprolol (M) e carvedilol (C) associados ao TF na IC em camundongos. MÉTODOS: Utilizamos modelo genético de IC induzida em camundongos por hiperatividade simpática. Inicialmente, dividimos os animais com IC em: sedentários (S); treinados (T); tratados com M (138 mg/kg) (M) ou C (65 mg/kg) (C). Na segunda parte, dividimos os grupos em S; treinado e tratado com M (MT) e treinado e tratado com C (CT). O TF consistiu em treinamento aeróbico em esteira por 8 semanas. A tolerância ao esforço foi avaliada por teste progressivo máximo e a fração de encurtamento foi avaliada (FE) por ecocardiografia. O diâmetro dos cardiomiócitos e a fração de colágeno foram avaliados por meio de análise histológica. Os dados foram comparados por ANOVA de um caminho com post hoc de Duncan. O nível de significância foi considerado p < 0,05. RESULTADOS: Destacando FE e remodelação cardíaca, verificamos que, isoladamente, T, M e C apresentaram melhora das variáveis. Na associação, após o período de intervenção, observamos aumento da tolerância ao esforço em MT e CT (43,0 por cento e 33,0 por cento, respectivamente). Houve também redução do diâmetro dos cardiomiócitos (10,0 por cento e 9,0 por cento, respectivamente) e da fração de colágeno (52,0 por cento e 63,0 por cento), após a intervenção. Porém, somente CT melhorou significantemente a FE. CONCLUSÃO: A associação do TF às terapias com M ou C proporcionou benefícios sobre a função e remodelação cardíaca em camundongos com IC.

BACKGROUND: Currently there are several types of interventions for the treatment of heart failure (HF). Among these are beta-blocker therapy (BB) and physical training (PT). However, the effects of the combination of these therapies are poorly studied. OBJECTIVE: To investigate the effects of BB treatment with metoprolol (M) and carvedilol (C) associated with PT in mice with HF. METHODS: We used a genetic model of sympathetic hyperactivity-induced heart failure in mice. Initially, we divided the HF animals into three groups: sedentary (S); trained (T); treated with M (138 mg/kg) (M); or C (65 mg/kg) (C). In the second part, we divided the groups into three subgroups: sedentary (S); trained and treated with M (TM); and trained and treated with C (CT). The PT consisted of aerobic training on a treadmill for 8 weeks. Exercise tolerance was assessed by maximal graded test, and fractional shortening (FS) was assessed by echocardiography. Cardiomyocyte diameter and collagen volume fraction were evaluated by histological analysis. Data were compared by one way ANOVA and post hoc Duncan test. The significance level was set at p < 0.05. RESULTS: As to FS and cardiac remodeling, we found that, in isolation, T, M, and C showed an improvement of the variables analyzed. As to therapy combination, after the intervention period, we observed an increase in exercise tolerance in MT and CT (43.0 percent and 33.0 percent respectively). There was also a reduction in cardiomyocyte diameter (10.0 percent and 9.0 percent respectively) and in collagen volume fraction (52.0 percent and 63.0 percent) after the intervention. However, only CT significantly improved FS. CONCLUSION: The association of PT with M or C therapies provided benefits on cardiac function and remodeling in HF mice.

FUNDAMENTO: El tratamiento de la insuficiencia cardiaca (IC) cuenta actualmente con diversos tipos de intervenciones. De entre ellas podemos destacar la terapia con betabloqueantes (BB) y el entrenamiento físico (EF). Con todo, los efectos de la asociación de estas terapias son poco estudiados. OBJETIVO: Verificar los efectos del tratamiento con BB, metoprolol (M) y carvedilol (C) asociados al EF en la IC en ratones. MÉTODOS: Utilizamos modelo genético de IC inducida en ratones por hiperactividad simpática. Inicialmente, dividimos los animales con IC en: sedentarios (S); entrenados (E); tratados con M (138 mg/kg) (M) o C (65 mg/kg) (C). En la segunda parte, dividimos los grupos en S; entrenado y tratado con M (ME) y entrenado y tratado con C (CE). El EF consistió en entrenamiento aeróbico en estera por 8 semanas. La tolerancia al esfuerzo se evaluó por prueba progresivo máxima y la fracción de acortamiento se evaluó (FE) por ecocardiografía. El diámetro de los cardiomiocitos y la fracción de colágeno fueron evaluados por medio de análisis histológico. Los dados fueron comparados por ANOVA de un camino con post hoc de Duncan. El nivel de significancia se consideró como p < 0,05. RESULTADOS: Destacando FE y remodelación cardíaca, verificamos que, aisladamente, E, M y C presentaron mejora de las variables. En la asociación, tras el período de intervención, observamos aumento de la tolerancia al esfuerzo en ME y CE (el 43 por ciento y el 33 por ciento, respectivamente). Hubo también reducción del diámetro de los cardiomiocitos (el 10 por ciento y el 9 por ciento, respectivamente) y de la fracción de colágeno (el 52 por ciento y el 63 por ciento), tras la intervención. Sin embargo, solamente CE mejoró significantemente la FE. CONCLUSIÓN: La asociación del EF a las terapias con M o C proporcionó beneficios sobre la función y remodelación cardíaca en ratones con IC.

Efeitos da associação entre treinamento físico e tratamento farmacológico com ß-bloqueadores sobre a cardiomiopatia induzida por hiperatividade simpática em camundongos / Effects of the association between exercise training and ß-blockers in a genetic model of sympathetic hyperactivity induced heart failure in mice

Adicionalmente às alterações estruturais e funcionais observadas na insuficiência cardíaca (IC), as alterações na dinâmica do Ca2+ intracelular apresentam uma relação negativa com a contratilidade e função cardíaca. Para evitar a progressão da IC, o tratamento desta síndrome, conta atualmente com intervenções multifatoriais, incluindo a terapia farmacológica, com destaque aos -bloqueadores, e a terapia não medicamentosa incluindo o treinamento físico aeróbico, que quando realizado em intensidade adequada melhora a tolerância ao esforço e a qualidade de vida do portador de insuficiência cardíaca. É bem conhecido que os -bloqueadores melhoram a função cardíaca e dinâmica do Ca2+ intracelular na IC, além de minimizar a remodelação cardíaca, no entanto, ainda existem controvérsias sobre qual o melhor -bloqueador a ser utilizado e seus efeitos específicos na regulação de Ca2+ intracelular. Quanto aos efeitos do treinamento físico aeróbico na IC, seu efeito é reconhecido na melhora da tolerância aos esforços e qualidade de vida do paciente, o que é atribuído principalmente, a ganhos vasculares e músculos-esqueléticos. Em relação à função cardíaca, em trabalho anterior do nosso laboratório, o treinamento físico aeróbico melhorou a função cardíaca associado à melhora nos transientes de cálcio do miócito cardíaco. Como tanto o treinamento físico como os -bloqueadores apresentaram seus respectivos efeitos positivos, mas diferenciados, na presente tese estudou-se o efeito associado do treinamento físico ao tratamento com -bloqueadores sobre a função cardíaca e o fluxo de cálcio no cardiomiócito. Além disso, comparou-se qual -bloqueador (metoprolol ou carvedilol) seria mais efetivo na associação com o treinamento físico. Dividimos nossa amostra em 6 grupos, todos com IC. Dentre eles, 3 foram mantidos sedentários; salina (S), metoprolol (M) e carvedilol (C) e 3 foram treinados; treinados (T), treinados e tratados com metoprolol (MT) e treinados e tratados com...

In heart failure (HF), structural and functional alterations in myocardium are often paralleled by, defects in intracellular Ca2+ transients.. Within therapeutical strategies for heart failure, it is worth mentioning -blockers and aerobic exercise training. It is known that -blockers improve cardiac function and Ca2+ handling in heart failure. Indeed, -blockers present cardiac antiremodeling effects, but there are many controversies concerning which - blocker is more efficient in HF treatment and which would be its specific effects in Ca2+ regulation. In relation to aerobic exercise training effects in HF, it is important to highlight its positive effects in exercise tolerance and life quality improvement associated with vascular and skeletal muscle gains. We also observed previously that exercise training improves cardiac function associated with improved calcium transients in cardiac myocytes. Taking into consideration the positive impact of both exercise training and -blockers, presently we studied the associative effect of exercise training and -blockers on cardiac function and Ca2+ handling in cardiomyocytes in sympathetic hyperactivity induced HF in mice. We further compared which -blocker (metoprolol or carvedilol) would be more effective to be associated with exercise training. HF mice were assigned into 6 different groups, being 3 of them sedentary: saline (S), metoprolol (M) and carvedilol (C) and 3 exercisetrained: trained (T), trained and treated with metoprolol (MT), and trained and treated with carvedilol (CT). We observed that only HF mice exercise-trained improved exercise tolerance evaluated by maximum exercise test on a treadmill, which was not observed in -blocker treatment alone. Both exercise training and -blockers improved cardiac function evaluated by echocardiography, respectively. When exercise training was associated with -blockers, only HF mice exercise-trained and carvedilol-treated improved cardiac function associated with...