Rogério Brandão Wichi

A brief review of chronic exercise intervention to prevent autonomic nervous system changes during the aging process

The aging process is associated with alterations in the cardiovascular and autonomic nervous systems. Autonomic changes related to aging involve parasympathetic and sympathetic alterations leading to a higher incidence of cardiovascular disease morbidity and mortality. Several studies have suggested that physical exercise is effective in preventing deleterious changes. Chronic exercise in geriatrics seems to be associated with improvement in the cardiovascular system and seems to promote a healthy lifestyle. In this review, we address the major effects of aging on the autonomic nervous system in the context of cardiovascular control. We examine the use of chronic exercise to prevent cardiovascular changes during the aging process.

Anabolic steroid associated to physical training induces deleterious cardiac effects.

PURPOSE Cardiac aldosterone might be involved in the deleterious effects of nandrolone decanoate (ND) on the heart. Therefore, we investigated the involvement of cardiac aldosterone, by the pharmacological block of AT1 or mineralocorticoid receptors, on cardiac hypertrophy and fibrosis. METHODS Male Wistar rats were randomized into eight groups (n = 14 per group): Control (C), nandrolone decanoate (ND), trained (T), trained ND (TND), ND + losartan (ND + L), trained ND + losartan (TND + L), ND + spironolactone (ND + S), and trained ND + spironolactone (TND + S). ND (10 mg·kg(-1)·wk(-1)) was administered during 10 wk of swimming training (five times per week). Losartan (20 mg·kg(-1)·d(-1)) and spironolactone (10 mg·kg(-1)·d(-1)) were administered in drinking water. RESULTS Cardiac hypertrophy was increased 10% by using ND and 17% by ND plus training (P < 0.05). In both groups, there was an increase in the collagen volumetric fraction (CVF) and cardiac collagen type III expression (P < 0.05). The ND treatment increased left ventricle-angiotensin-converting enzyme I activity, AT1 receptor expression, aldosterone synthase (CYP11B2), and 11-β hydroxysteroid dehydrogenase 2 (11β-HSD2) gene expression and inflammatory markers, TGFβ and osteopontin. Both losartan and spironolactone inhibited the increase of CVF and collagen type III. In addition, both treatments inhibited the increase in left ventricle-angiotensin-converting enzyme I activity, CYP11B2, 11β-HSD2, TGFβ, and osteopontin induced by the ND treatment. CONCLUSIONS We believe this is the first study to show the effects of ND on cardiac aldosterone. Our results suggest that these effects may be associated to TGFβ and osteopontin. Thus, we conclude that the cardiac aldosterone has an important role on the deleterious effects on the heart induced by ND.

Sildenafil: two decades of benefits or risks?

Abstract Sildenafil is a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE-5). A patent was registered for this drug in 1990, which expired in 2010. Since expiration, the drug has been marketed under various trade names or as generic drugs. Numerous clinical trials have been conducted addressing the effectiveness of the drug for erectile dysfunction (ED) and its safety regarding the presence or absence of specific comorbidities. After over 20 years in the market, we need to ask: has the scientific community reached a general consensus as to the overall efficacy and safety of the drug? Can we firmly state that the benefits of the drug outweigh its risks? This review suggests that sildenafil is an effective and easily manageable treatment for erectile dysfunction, both in the absence and in the presence of comorbidities. After two decades of the emergence of sildenafil as a drug of choice for the treatment of ED (and the numerous studies and clinical trials undertaken during this time span), it is now possible to state that the benefits of the drug do outweigh the risks, and represent an significant improvement in the quality of life in men with ED.

Exercise improves cardiovascular control in a model of dislipidemia and menopause.

The present study investigated the effects of exercise training on arterial pressure, baroreflex sensitivity, cardiovascular autonomic control and metabolic parameters on female LDL-receptor knockout ovariectomized mice. Mice were divided into two groups: sedentary and trained. Trained group was submitted to an exercise training protocol. Blood cholesterol was measured. Arterial pressure (AP) signals were directly recorded in conscious mice. Baroreflex sensitivity was evaluated by tachycardic and bradycardic responses to AP changes. Cardiovascular autonomic modulation was measured in frequency (FFT) and time domains. Maximal exercise capacity was increased in trained as compared to sedentary group. Blood cholesterol was diminished in trained mice (191+/-8mg/dL) when compared to sedentary mice (250+/-9mg/dL, p<0.05). Mean AP and HR were reduced in trained group (101+/-3mmHg and 535+/-14bpm, p<0.05) when compared with sedentary group (125+/-3mmHg and 600+/-12bpm). Exercise training induced improvement in bradycardic reflex response in trained animals (-4.24+/-0.62bpm/mmHg) in relation to sedentary animals (-1.49+/-0.15bpm/mmHg, p<0.01); tachycardic reflex responses were similar between studied groups. Exercise training increased the variance (34+/-8 vs. 6.6+/-1.5ms(2) in sedentary, p<0.005) and the high-frequency band (HF) of the pulse interval (IP) (53+/-7% vs. 26+/-6% in sedentary, p<0.01). It is tempting to speculate that results of this experimental study might represent a rationale for this non-pharmacological intervention in the management of cardiovascular risk factors in dyslipidemic post-menopause women.

Low-dose enalapril reduces angiotensin II and attenuates diabetic-induced cardiac and autonomic dysfunctions.

Abstract Activation of renin–angiotensin system has been linked to cardiovascular and autonomic dysfunctions in diabetes. Experiments were performed to investigate the effects of angiotensin-converting enzyme inhibitor (ACEI), enalapril, on cardiac and autonomic functions in diabetic rats. Diabetes was induced by streptozotocin (50 mg/kg), and rats were treated with enalapril (1 mg·kg−1·d−1). After 30 days, evaluations were performed in control, diabetic, and enalapril-treated groups. Cardiac function was evaluated by echocardiography and through cannulation of the left ventricle (at baseline and in response to volume overload). Heart rate and systolic blood pressure variabilities were evaluated in the time and frequency domains. Streptozotocin rats had left ventricular systolic and diastolic dysfunctions, expressed by reduced ejection fraction and increased isovolumic relaxation time. The ACEI prevented these changes, improved diastolic cardiac responses to volume overload and total power of heart rate variability, reduced the ACE1 activity and protein expression and cardiac angiotensin (Ang) II levels, and increased angiotensin-converting enzyme 2 activity, despite unchanged blood pressure. Correlations were obtained between Ang II content with systolic and diastolic functions and heart rate variability. These findings provide evidence that the low-dose ACEI prevents autonomic and cardiac dysfunctions induced by diabetes without changing blood pressure and associated with reduced cardiac Ang II and increased angiotensin-converting enzyme 2 activity.

Monosodium glutamate neonatal treatment induces cardiovascular autonomic function changes in rodents

OBJECTIVES: The aim of this study was to evaluate cardiovascular autonomic function in a rodent obesity model induced by monosodium glutamate injections during the first seven days of life. METHOD: The animals were assigned to control (control, n = 10) and monosodium glutamate (monosodium glutamate, n = 13) groups. Thirty-three weeks after birth, arterial and venous catheters were implanted for arterial pressure measurements, drug administration, and blood sampling. Baroreflex sensitivity was evaluated according to the tachycardic and bradycardic responses induced by sodium nitroprusside and phenylephrine infusion, respectively. Sympathetic and vagal effects were determined by administering methylatropine and propranolol. RESULTS: Body weight, Lee index, and epididymal white adipose tissue values were higher in the monosodium glutamate group in comparison to the control group. The monosodium glutamate-treated rats displayed insulin resistance, as shown by a reduced glucose/insulin index (-62.5%), an increased area under the curve of total insulin secretion during glucose overload (39.3%), and basal hyperinsulinemia. The mean arterial pressure values were higher in the monosodium glutamate rats, whereas heart rate variability (>7 times), bradycardic responses (>4 times), and vagal (∼38%) and sympathetic effects (∼36%) were reduced as compared to the control group. CONCLUSION: Our results suggest that obesity induced by neonatal monosodium glutamate treatment impairs cardiac autonomic function and most likely contributes to increased arterial pressure and insulin resistance.

Endothelium adjustments to acute resistance exercise are intensity-dependent in healthy animals

AIMS We evaluated the acute effects of different intensities of resistance exercise over endothelium-dependent vasodilatation, eNOSser1177 phosphorylation level and endothelial production of NO in superior mesenteric artery of healthy rats. MAIN METHODS Groups: control (Ct), resistance exercise in the intensities of 30% (Ex30%), 50% (Ex50%) and 70% (Ex70%) of the maximal load established by the maximal repetition test (1RM). Exercise protocol: 15 sets of 10 repetitions. The rings of mesenteric artery were mounted in an isometric system or were prepared for further implementation of Western blot and DAF-FM techniques. KEY FINDINGS The maximal response of the relaxation induced by insulin was not altered in the animals of the Ex30% group when compared to the Ct group. However, the animals of the Ex50% and Ex70% groups presented an increase in this response when compared to the Ct group. The eNOSser1177 phosphorylation levels showed an increase in Ex50% and Ex70% groups when compared to the Ct (1.6-fold and 3.3-fold, respectively). In the endothelial production of NO, it was observed that the Ex30% group did not show alteration in the NO production when compared to the Ct group. On the other hand, the animals exercised in the Ex50% and Ex70% groups showed increase in the NO synthesis when compared to the animals in the Ct group. SIGNIFICANCE Our results suggest that the magnitude of these vascular endothelium adjustments is strongly related to the increase of the resistance exercise intensity from the intensity of 50% of 1 RM.

Resistance Exercise Restores Endothelial Function and Reduces Blood Pressure in Type 1 Diabetic Rats

Background Resistance exercise effects on cardiovascular parameters are not consistent. Objectives The effects of resistance exercise on changes in blood glucose, blood pressure and vascular reactivity were evaluated in diabetic rats. Methods Wistar rats were divided into three groups: control group (n = 8); sedentary diabetic (n = 8); and trained diabetic (n = 8). Resistance exercise was carried out in a squat device for rats and consisted of three sets of ten repetitions with an intensity of 50%, three times per week, for eight weeks. Changes in vascular reactivity were evaluated in superior mesenteric artery rings. Results A significant reduction in the maximum response of acetylcholine-induced relaxation was observed in the sedentary diabetic group (78.1 ± 2%) and an increase in the trained diabetic group (95 ± 3%) without changing potency. In the presence of NG-nitro-L-arginine methyl ester, the acetylcholine-induced relaxation was significantly reduced in the control and trained diabetic groups, but not in the sedentary diabetic group. Furthermore, a significant increase (p < 0.05) in mean arterial blood pressure was observed in the sedentary diabetic group (104.9 ± 5 to 126.7 ± 5 mmHg) as compared to that in the control group. However, the trained diabetic group showed a significant decrease (p < 0.05) in the mean arterial blood pressure levels (126.7 ± 5 to 105.1 ± 4 mmHg) as compared to the sedentary diabetic group. Conclusions Resistance exercise could restore endothelial function and prevent an increase in arterial blood pressure in type 1 diabetic rats.

Efeito do treinamento de força nas variáveis cardiovasculares em adolescentes com sobrepeso

OBJETIVO: O presente estudo teve por objetivo avaliar as respostas agudas cardiorrespiratorias e autonomicas induzidas por uma sessao de exercicio fisico resistido em adolescentes com sobrepeso.METODOS: Foram avaliados 17 adolescentes do sexo masculino divididos em grupo controle (GC, n=9) e grupo sobrepeso (GSO, n=7). Todos foram submetidos a uma sessao exercicios resistidos para diferentes grupos musculares, realizados com sobrecarga de 60% da forca maxima, com um intervalo de 45 segundos entre as series e 90 segundos entre cada exercicio. Antes, durante e apos a sessao de exercicios os seguintes parâmetros foram avaliados: frequencia cardiaca (FC), pressao arterial sistolica (PAS), pressao arterial diastolica (PAD) e variabilidade da frequencia cardiaca (VFC).RESULTADOS: Foi observado comportamento semelhante em ambos os grupos da PAS e PAD. A PAS aumentou durante o exercicio e a PAD diminuiu. Ambas retornaram aos valores basais durante a recuperacao. A FC aumentou durante a sessao de exercicio nos dois grupos, porem, apenas no GSO houve retorno aos valores de repouso. Os indices da VFC no dominio do tempo (VAR RR e RMSSD) se comportaram de maneira semelhante frente ao exercicio nos dois grupos, porem, no indice SDNN apenas o GSO retornou aos valores de repouso. A VFC no dominio da frequencia apresentou comportamento semelhante em ambos os grupos.CONCLUSOES: sugere-se que o aumento do nivel de atividade fisica em individuos com sobrepeso pode prevenir as alteracoes autonomicas que estao associadas ao aumento do peso corporal e conferir efeito protetor ao sistema cardiovascular.

Prevalência de sobrepeso e obesidade infantil em instituições de ensino: públicas vs. privadas

INTRODUCCION: los datos epidemiologicos indican que la obesidad infantil se ha incrementado en Brasil y que se identifica como un factor de riesgo para el desarrollo temprano de las enfermedades cronicas. La obesidad se ha caracterizado por un aumento de tejido adiposo y del peso corporal.OBJETIVO: diagnosticar y comparar la prevalencia de sobrepeso y obesidad en escolares de instituciones educativas publicas EPU y privadas EPR. Ademas, se encontro una correlacion entre el IMC y el porcentaje de grasa corporal en ninos de ambos sexos.METODOS: se evaluaron las variables antropometricas IMC y DOC [pliegues cutaneos] de ninos n = 91 y ninas n = 109 de entre 8 y 10 anos de edad. Hubo una mayor prevalencia de sobrepeso en los ninos 19,6% y ninas 25,5% de EPR en comparacion con los ninos 6,7% y ninas 8,1% de EPU. El nivel de obesidad fue mayor en los ninos 34,8% y ninas 31,9% de EPR en comparacion con los ninos 6,7% y ninas 6,5% de EPU. Una correlacion positiva se obtuvo entre las variables IMC y el porcentaje de grasa corporal de los ninos r = 0,82 y ninas r = 0,85.RESULTADOS: los resultados sugieren que, a pesar del aumento en todas las clases sociales, el sobrepeso y la obesidad eran mas presentes en aquellos con mayor poder economico, por lo tanto existe una relacion socioeconomica. Este hecho puede dar lugar a un estado de salud mas cerca de un polo negativo.CONCLUSION: el analisis de IMC resulto ser un indice para la determinacion eficiente de sobrepeso y obesidad en los ninos.introduction: epidemiological data indicate that childhood obesity is increasing in brazil and is identified as a risk factor for early development of chronic diseases. obesity has been characterized by increased adipose tissue and body weight. objective: to diagnose and compare the prevalence of overweight and obesity in schoolchildren from public (ePu) and private (ePr) schools. Methods: anthropometrics variables (bMi and doc [skin folds]) were evaluated in boys (n=91) and girls (n=109) between 8 and 10 years old. there was a higher prevalence of overweight in boys (19.6%) and girls (25.5%) of the ePr compared to boys (6.7%) and girls (8.1%) of the ePu. the obesity level was higher in boys (34.8%) and girls (31.9%) of the ePr compared to boys (6.7%) and girls (6.5%) of the ePu. Positive correlation was obtained between the variables bMi and % body fat in boys (r=0.82) and girls (r=0.85). results: the results suggest that despite the increase in all social classes, overweight and obesity prevalence were more present in those with higher economic status, confirming therefore a socioeconomic relationship. this finding may lead to a health condition closest to the negative pole. conclusion: the bMi analysis proved to be an index for efficient determination of overweight and obesity in children.