Weight loss enhances hepatic antioxidant status in a NAFLD model induced by high-fat diet.

Nonalcoholic fatty liver disease (NAFLD) is a benign condition that can progress to more severe liver damage in a process mediated, in part, by disturbances in redox balance. Additionally, some argue that it is set to become the main cause of end-stage liver disease in the near future. Here, we investigated whether diet-induced weight loss is able to reverse hepatic lipid accumulation and reduce oxidative stress in liver from C57BL/6 mice fed a high-fat (HF) diet. Male C57BL/6 mice were divided into 4 groups: standard chow (SC; 10% energy from fat, 16 weeks); HF (50% energy from fat, 16 weeks); SC-HF (SC for 8 weeks followed by HF for 8 weeks); and HF-SC (HF for 8 weeks followed by SC for 8 weeks). The HF diet during 8 (SC-HF) and 16 weeks (HF) downregulated messenger RNA levels and protein expression of Nrf2 and endogenous antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase) in the liver; caused liver steatosis; affected liver function markers; increased intra-abdominal and subcutaneous adipose tissue; and induced glucose intolerance and hypercholesterolemia compared with controls (SC). Diet-induced weight loss significantly reduced the intrahepatic lipid accumulation, improved glucose tolerance, and restored both gene and protein expression of the antioxidant enzymes. Our findings suggest that a dietary intervention aimed to induce weight loss may exert protective effects in NAFLD as it can reduce hepatic oxidative stress and intrahepatic lipid accumulation, which can hinder the progression of this condition to more severe states.

Erythrocyte nitric oxide availability and oxidative stress following exercise.

Growing evidence has shown that acute exercise impairs erythrocyte membrane structure and function as a consequence of increased physical and chemical stress. Erythrocyte-synthesized nitric oxide (NO) is known to modulate membrane fluidity, and its bioavailability depends on the balance between its production and scavenging by reactive oxygen species. Here, we investigated whether a maximal exercise test could affect erythrocyte NO bioavailability and oxidative stress. Twelve men (26±4 years old, V̇O2peak 44.1±4.3 mL·kg-1·min-1) performed a treadmill maximal cardiopulmonary exercise test. Blood was collected at rest and immediately after exercise for erythrocytes isolation. Maximal exercise caused an increase in erythrocytes count, haemoglobin and haematocrit levels. There was no change in L-arginine influx into erythrocytes after exercise. Yet, nitric oxide synthase activity, and thus, NO production, was increased after maximal test, as well cyclic GMP levels. In relation to biomarkers of oxidative stress, maximal test resulted in increased levels of lipid peroxidation, and diminished superoxide dismutase activity. Neither glutathione peroxidase nor catalase activity was affected by maximal test. Our findings demonstrate that the increased erythrocyte membrane rigidity caused by an acute bout of exercise may be caused, in part, by an increased lipid oxidative damage caused by ROS produced exogenously.

Effects of non-surgical periodontal treatment on the L-arginine-nitric oxide pathway and oxidative status in platelets.

Several studies have suggested an increase of cardiovascular disease (CVD) risk on periodontitis patients. An enhancement has been demonstrated on both platelet activation and oxidative stress on periodontitis patients, which may contribute for this association. Therefore, the aim of this study was to evaluate the effects of non-surgical periodontal treatment on the l-arginine-nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) pathway and oxidative status in platelets. A total of eight periodontitis patients and eight controls were included in this study. Clinical, laboratory and experimental evaluations were performed on baseline and 90 days after periodontal treatment (except for western blot analysis). The clinical periodontal evaluation included measurements of probing pocket depth (PPD), clinical attachment loss (CAL), % of sites with plaque and % of sites with bleeding on probing. We evaluated: l-[(3)H]arginine influx; nitric oxide synthase (NOS) and arginase enzymes activity and expression; expression of guanylate cyclase and phosphodiesterase-5 enzymes; cGMP levels; platelet aggregation; oxidative status through superoxide dismutase (SOD) and catalase activities, and measurement of reactive oxygen species (ROS) levels and C-reactive protein (CRP) levels. The initial results showed an activation of both l-arginine influx and via system y (+ )L associated with reduced intraplatelet cGMP levels in periodontitis patients and increased systemic levels of CRP. After periodontal treatment, there was a significant reduction of the % of sites with PPD 4-5mm, % of sites with CAL 4-5 mm, and an enhancement in cGMP levels and SOD activity. Moreover, CRP levels were reduced after treatment. Therefore, alterations in the intraplatelet l-arginine-NO-cGMP pathway and oxidant-antioxidant balance associated with a systemic inflammatory response may lead to platelet dysfunction, which may contribute to a higher risk of CVD in periodontitis.

Low plasma levels of L-arginine, impaired intraplatelet nitric oxide and platelet hyperaggregability: implications for cardiovascular disease in depressive patients.

BACKGROUND: Major depression (MD) is an independent cardiovascular risk factor, but the exact mechanisms are not clear. In this study we have investigated the intraplatelet L-arginine-nitric oxide (NO) pathway and platelet function in depressive patients. METHODS: Nineteen unmedicated patients with MD (34±4years) and 19 control subjects (CS, 34±3years) were included. L-[(3)H]-arginine influx, NO synthase (NOS) activity and intracellular cGMP levels were evaluated in platelets, as well as the expression of eNOS, iNOS, arginase and soluble guanylate cyclase (sGC), platelet aggregation and the systemic amino acid profile in MD patients and CS. RESULTS: L-arginine influx (pmol/10(9)cells/min) in platelets was reduced from 46.2±9.5 to 20.02±2.12 in depression. NOS activity (pmol/10(8) cells) was diminished in MD patients (0.09±0.01) compared to CS (0.17±0.01). Intracellular cGMP levels were also impaired in MD patients associated with hyperaggregability. Moreover, the concentration of plasma L-arginine was reduced by 20% in MD patients. The expression of eNOS, iNOS, arginase II and sGC in platelet lysates was not affected by MD. LIMITATIONS: Small number of patients in the study. CONCLUSIONS: This study has demonstrated an impairment of L-arginine-NO signaling in platelets from MD patients, suggesting a role in platelet activation and cardiovascular events.

Evidências biológicas do treino de controle do stress em pacientes com hipertensão / Biological evidences of the stress management training in patients with hypertension

O presente estudo objetivou avaliar o efeito do treino de controle de stress (TCS) em um grupo de pacientes hipertensas. Utilizou-se como critério para avaliação alterações na via L-arginina-óxido nítrico (NO). Participaram do estudo mulheres hipertensas (n=44) e normotensas (n=25), sendo que o TCS em grupo foi administrado em 14 hipertensas, observando-se as mudanças no nível de stress e no transporte da L-arginina. Em hipertensão, o transporte de L-arginina, através do sistema y+L, mostrou-se reduzido, assim como o transporte de L-arginina pelos sistemas y+L e y+ em pacientes hipertensas estressadas quando comparadas com normotensas estressadas. A redução do stress pelo TCS em hipertensas estressadas, restaurou o transporte de L-arginina através do sistema y+ em níveis observados em pacientes hipertensas não-estressadas.

The objective of the present study was to evaluate the effect of stress management training in a group of hypertensive patients. Alterations of L-arginine-nitric oxide (NO) pathway were used as an evaluation criterion. Hypertensive (n=44) and normotensive (n=25) women participated in this study, and the stress management training was performed with a group of 14 hypertensive patients, observing the changes in the stress level and in L-arginine transport. In hypertension, the transport of L-arginine, via system y+, was reduced. Moreover, stressed hypertensive patients had a reduction of L-arginine transport by both systems, y+ and y+L, compared to stressed normotensive patients. The reduction of stress with stress management training in stressed hypertensive patients restored the transport of L-arginine via system y+ to the same levels of non-stressed hypertensive patients.

Evidências biológicas do treino de controle do stress em pacientes com hipertensão

O presente estudo objetivou avaliar o efeito do treino de controle de stress (TCS) em um grupo de pacientes hipertensas. Utilizou-se como critério para avaliação alterações na via L-arginina-óxido nítrico (NO). Participaram do estudo mulheres hipertensas (n=44) e normotensas (n=25), sendo que o TCS em grupo foi administrado em 14 hipertensas, observando-se as mudanças no nível de stress e no transporte da L-arginina. Em hipertensão, o transporte de L-arginina, através do sistema y+L, mostrou-se reduzido, assim como o transporte de L-arginina pelos sistemas y+L e y+ em pacientes hipertensas estressadas quando comparadas com normotensas estressadas. A redução do stress pelo TCS em hipertensas estressadas, restaurou o transporte de L-arginina através do sistema y+ em níveis observados em pacientes hipertensas não-estressadas.(AU)

The objective of the present study was to evaluate the effect of stress management training in a group of hypertensive patients. Alterations of L-arginine-nitric oxide (NO) pathway were used as an evaluation criterion. Hypertensive (n=44) and normotensive (n=25) women participated in this study, and the stress management training was performed with a group of 14 hypertensive patients, observing the changes in the stress level and in L-arginine transport. In hypertension, the transport of L-arginine, via system y+, was reduced. Moreover, stressed hypertensive patients had a reduction of L-arginine transport by both systems, y+ and y+L, compared to stressed normotensive patients. The reduction of stress with stress management training in stressed hypertensive patients restored the transport of L-arginine via system y+ to the same levels of non-stressed hypertensive patients.(AU)

Direct duplex scanning parameters in the diagnosis of renal artery stenosis: a study to validate and optimize cut-off points.

OBJECTIVE: To test the efficiency of the direct duplex scanning parameters in the diagnosis of renal artery stenosis (RAS), and verify whether or not the cut-off points recommended by medical literature are the most appropriate means to distinguish lesion severity. METHODS: Prospective study, including 62 patients with RAS, submitted to a duplex ultrasound scan and selective arteriography. The peak systolic velocity (PSV) and the renal-aortic ratio (RAR) were measured. Statistical analysis included the ROC (receiver operating characteristic curve), unpaired students t-test, sensitivity, specificity, positive and negative predictive values and accuracy. RESULTS: The arteriography revealed RAS 0-59% in 31 arteries (24%); RAS 60-99% in 91 arteries (72%) and 5 occlusions (4%). ROC analysis demonstrated that the lesion detection efficiency of PSV and RAR were similar with areas below the curves of 0.96 and 0.95, respectively. Considering the cut-off points recommended by medical literature, PSV of 180 cm/sec presented a sensitivity of 100% and specificity of 81%, while the RAR of 3.5 presented a sensitivity of only 79%, with a specificity of 93%. These parameters were analyzed in conjunction (direct criteria) revealing a sensitivity of 79% and specificity of 97%. The optimized cut-off points were: PSV of 189 cm/sec and RAR of 2.6, demonstrating sensitivity and specificity rates of 100%, 87%, 96% and 87% respectively. CONCLUSION: The individual use of optimized peak systolic velocity (PSV) was the most efficient parameter in the detection and grading of RAS.

Parâmetros diretos do duplex scan no diagnóstico da estenose da artéria renal: estudo de validação e otimização dos pontos de corte / Direct duplex scanning parameters in the diagnosis of renal artery stenosis: a study to validate and optimize cut-off points

OBJETIVO: Testar o desempenho dos parâmetros diretos do duplex scan no diagnóstico da estenose da artéria renal (EAR) e verificar se os pontos de corte recomendados pela literatura são os mais adequados para se discriminar a gravidade da lesão. MÉTODOS: Estudo prospectivo, incluindo 62 pacientes portadores de EAR, submetidos ao duplex scan, seguido da arteriografia seletiva. O pico de velocidade sistólico (PVS) e a relação renal-aorta (RRA) foram mensurados. A análise estatística incluiu a curva ROC (receiver operating characteristic curve), t test student não pareado a sensibilidade, especificidade, os valores preditivos positivo e negativo, e a acurácia. RESULTADOS: A arteriografia revelou EAR 0-59 por cento em 31 artérias (24 por cento); EAR 60-99 por cento em 91 artérias (72 por cento) e 5 oclusões (4 por cento). A análise de ROC mostrou que o PVS e a RRA apresentaram desempenho semelhante na detecção da lesão, cujas áreas sob as curvas foram 0,96 e 0,95, respectivamente. Considerando os pontos de corte recomendados pela literatura, o PVS de 180 cm/s apresentou sensibilidade de 100 por cento e especificidade de 81 por cento, enquanto que a RRA de 3,5 apresentou sensibilidade de somente 79 por cento, com 93 por cento de especificidade. Estes parâmetros foram analisados de forma conjugada (critério direto), revelando 79 por cento de sensibilidade e 97 por cento de especificidade. Os pontos de corte otimizados foram: PVS de 189 cm/s e RRA de 2,6, demonstrando 100 por cento, 87 por cento, 96 por cento e 87 por cento de sensibilidade e especificidade para o PVS e para a RRA, respectivamente. CONCLUSÃO: O uso isolado do PVS otimizado apresentou o melhor desempenho na detecção e na graduação da EAR.

OBJECTIVE: To test the efficiency of the direct duplex scanning parameters in the diagnosis of renal artery stenosis (RAS), and verify whether or not the cut-off points recommended by medical literature are the most appropriate means to distinguish lesion severity. METHODS: Prospective study, including 62 patients with RAS, submitted to a duplex ultrasound scan and selective arteriography. The peak systolic velocity (PSV) and the renal-aortic ratio (RAR) were measured. Statistical analysis included the ROC (receiver operating characteristic curve), unpaired studentÆs t-test, sensitivity, specificity, positive and negative predictive values and accuracy. RESULTS: The arteriography revealed RAS 0-59 percent in 31 arteries (24 percent); RAS 60-99 percent in 91 arteries (72 percent) and 5 occlusions (4 percent). ROC analysis demonstrated that the lesion detection efficiency of PSV and RAR were similar with areas below the curves of 0.96 and 0.95, respectively. Considering the cut-off points recommended by medical literature, PSV of 180 cm/sec presented a sensitivity of 100 percent and specificity of 81 percent, while the RAR of 3.5 presented a sensitivity of only 79 percent, with a specificity of 93 percent. These parameters were analyzed in conjunction (direct criteria) revealing a sensitivity of 79 percent and specificity of 97 percent. The optimized cut-off points were: PSV of 189 cm/sec and RAR of 2.6, demonstrating sensitivity and specificity rates of 100 percent, 87 percent, 96 percent and 87 percent respectively. CONCLUSION: The individual use of optimized peak systolic velocity (PSV) was the most efficient parameter in the detection and grading of RAS.

Efeitos da atividade aeróbica sobre a função cardiovascular na fase III da cirurgia de revascularização do miocárdio / Effects of aerobic exercise on cardiovascular function in the phase III of coronary artery bypass grafting

A intervenção fisioterápica pode adicionar qualidade de vida por meio do aumento da capacidade de trabalho e da atividade física em geral, ajudando a normalizar o estilo de vida dos pacientes cardiopatas. A fisioterapia, para esses indivíduos, pode ir desde exercícios no leito até exercício vigoroso de condicionamento físico. O objetivo deste estudo foi investigar os efeitos da fisioterapia sobre a função cardiovascular na fase III da cirurgia de revascularização do miocárdio após três meses de tratamento em nosso meio. foram estudados 37 pacientes revascularizados, com média de idade de 63 maior ou menor que 7,7 anos, do Hospital Universitário Pedro Ernesto (UERJ), no Rio de Janeiro. Foram realizadas três sessões de tratamento semanais, cada uma delas dividida em três fases: aquecimento, parte aeróbica e desaquecimento. A intensidade do exercício foi ajustada a 70 por cento a 75 por cento da frequência cardíaca atingida no teste ergométrico...

Insuficiência cardíaca crônica e óxido nítrico / Chronic heart failure and nitric oxide

O presente tabalho tem por objetivo realizar um levantamento do papel do óxido nítrico (NO) e de seu precursor L-arginina no contexto da síndrome de insuficiência cardíaca crônica