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.

Platelet hyperaggregability in obesity: is there a role for nitric oxide impairment and oxidative stress?

Epidemiological evidence has shown that platelet activation markers are consistently elevated in obesity, contributing to its prothrombotic state. In order to improve the understanding of the regulation of platelet function in obesity, the aim of this study was to investigate the l-arginine-nitric oxide (NO) pathway in obese adults without other cardiovascular risk factor. Seventeen obese (body mass index [BMI] 35.

Major depression induces oxidative stress and platelet hyperaggregability.

We have previously demonstrated an impairment of intraplatelet L-arginine-nitric oxide-cGMP pathway in major depression (MD) associated to platelet dysfunction. Here, we evaluated arginase pathway and phosphodiesterase 5 (PDE5) expression in platelets, systemic and intraplatelet oxidative status in untreated MD patients, and their effects on platelet aggregation. Blood samples were collected from 22 treatment naive MD patients (31 ± 2 yr) and 27 healthy subjects (33 ± 2 yr).

Diminished nitric oxide generation from neutrophils suppresses platelet activation in chronic renal failure.

Chronic renal failure (CRF) is a complex clinical condition associated with accelerated atherosclerosis and thrombosis leading to cardiovascular events. The aim of this study was to investigate in detail the NO pathway in neutrophils obtained from hemodialysis patients and its association with platelet function and oxidative status. Fifteen CRF patients on hemodialysis and fifteen controls were included in this study.

Hyperaggregability and impaired nitric oxide production in platelets from postmenopausal women.

Objective: Cardiovascular mortality increases after menopause in women. Nitric oxide is essential for proper platelet function inhibiting its aggregation and maintaining vascular haemostasis. Here, we investigated whether platelet function and intraplatelet l-arginine-nitric oxide pathway are impaired in postmenopausal women.

Role of dietary fish oil on nitric oxide synthase activity and oxidative status in mice red blood cells.

The consumption of n-3 polyunsaturated fatty acids (PUFAs) derived from fish oil concomitant with a reduced intake of saturated fats is associated with cardiovascular benefits, which may result from the participation of nitric oxide (NO). In contrast, PUFAs are vulnerable to peroxidation, which could affect the oxidative stability of the cell and reduce NO bioavailability. Therefore, we investigated the effects of high fat diets with increasing amounts of fish oil (0-40% of energy) in place of lard on the l-arginine-NO pathway, the arginase pathway and oxidative status in mice red blood cells (RBC).

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.

Chronic exercise leads to antiaggregant, antioxidant and anti-inflammatory effects in heart failure patients.

Background: Heart failure (HF) patients are at an increased risk of thrombotic events. Here, we investigated the effects of exercise training on platelet function and factors involved in its modulation in HF.

Design And Methods: Thirty HF patients were randomized to 6 months of supervised exercise training or to a control group that remained sedentary.

L-arginine-nitric oxide pathway and oxidative stress in plasma and platelets of patients with pre-eclampsia.

Pre-eclampsia (PE), a syndrome of pregnancy-induced hypertension, continues to be a leading cause of maternal and fetal morbidity and mortality. The aim of this study was to investigate whether changes in oxidative status are correlated with alterations in the L-arginine-nitric oxide pathway and platelet aggregation in PE. Plasma and platelets from women with PE (n=24) or normotensive pregnancy (NP, n=27) recruited in the third trimester of gestation were used to measure oxidative damage assessed by protein carbonyl content, antioxidant activities of superoxide dismutase (SOD), catalase (CAT) and nitrite levels.

Defective nitric oxide-cyclic guanosine monophosphate signaling in patients with bipolar disorder: a potential role for platelet dysfunction.

Objective: Bipolar disorder (BD) is associated with elevated cardiovascular mortality rates. We investigated the modulation of l-arginine-nitric oxide (NO) signaling in platelets from patients with BD at different phases.

Methods: Platelets obtained from 28 patients with BD and 10 healthy volunteers were analyzed for l-arginine transport, NO synthase (NOS) activity, cyclic guanosine monophosphate content, and biomarkers of oxidative stress.

Upregulation of platelet (L)-arginine: nitric oxide pathway after exercise training in hypertension.

We investigated whether physical exercise can affect platelet L-arginine - nitric oxide pathway in spontaneously hypertensive rats (SHR). Sixteen male SHR and 16 Wistar Kyoto rats (WKY) were divided among exercise (EX) and sedentary (SED) groups. After 20 weeks of treadmill training, systolic blood pressure (mm Hg) was significantly lower in exercised spontaneously hypertensive rats (SHR/EX; 138 ± 8) than in sedentary spontaneously hypertensive rats (SHR/SED; 214 ± 9).

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.

Nitric oxide activity in platelets of dengue haemorrhagic fever patients: the apparent paradoxical role of ADMA and l-NMMA.

Dengue haemorrhagic fever (DHF) is a prevalent acute disease that occurs in patients infected by an arbovirus in tropical and subtropical regions. We have previously shown increased intraplatelet nitric oxide (NO) production in patients with dengue fever associated with reduced platelet aggregation. In this study, l-arginine transport as well as expression and activity of nitric oxide synthase (NOS) isoforms in the presence or absence of l-arginine analogues were examined in 23 DHF patients.

Platelet activation, oxidative stress and overexpression of inducible nitric oxide synthase in moderate heart failure.

1. Chronic heart failure (CHF) is a common disabling disorder associated with thromboembolic events, the genesis of which is not yet fully understood. Nitric oxide (NO), derived from the vascular endothelium and platelets, has an important role in the physiological regulation of blood flow.

Increased nitric oxide production in platelets from severe chronic renal failure patients.

Nitric oxide (NO) production occurs through oxidation of the amino acid L-arginine by NO synthase (NOS). NO inhibits platelet activation by increasing the levels of cyclic guanosine monophosphate (cGMP), thus maintaining vascular homeostasis. Our group previously demonstrated (da Silva et al.

Insulin resistance in obesity and metabolic syndrome: is there a connection with platelet l-arginine transport?

Objective: Nitric oxide (NO) is a short-lived gaseous messenger with multiple physiological functions including regulation of blood flow, platelet adhesion and aggregation inhibition. NO synthases (NOS) catalyze the conversion of cationic amino acid L-arginine in L-citrulline and NO. Despite an increasing prevalence of obesity and metabolic syndrome (MetS) in the last decades, the exact mechanisms involved in the pathogenesis and cardiovascular complications are not fully understood.

Characterization of the L-arginine-NO-cGMP pathway in spontaneously hypertensive rat platelets: the effects of pregnancy.

Nitric oxide (NO) is a short-lived intercellular messenger that provides an efficient vascular regulatory mechanism to support homeostasis and prevent thrombosis. Endothelial dysfunction and reduced NO bioavailability have a central role in hypertension associated with pregnancy. The purpose of this study was to investigate the impact of pregnancy on the L-arginine-NO-cGMP pathway in platelets and its correlation to platelet function and blood pressure in normotensive rats and spontaneously hypertensive rats (SHRs).

Exercise training in doxorubicin-induced heart failure: effects on the L-arginine-NO pathway and vascular reactivity.

Heart failure (HF) is the end-stage of cardiovascular disease and is associated with a high incidence of thrombotic events. Nitric oxide (NO) mediates vasodilation and prevents platelet activation, providing an important antithrombotic effect. The aim of this study was to investigate the effects of aerobic training on survival, platelet L-arginine-NO pathway, and vasodilator properties in doxorubicin (DOX)-induced HF.

Nitric oxide and oral diseases: can we talk about it?

Nitric oxide (NO) is a short-lived intercellular messenger with multiple biological implications, such as regulation of blood pressure, inhibition of platelet adhesion and aggregation, bacterial-challenge and cytokine stimulation, and regulation of mineralized tissue function. NO synthase (NOS) catalyses the conversion of cationic amino acid L-arginine to L-citrulline and NO. Recently there is an increasing interest in the role of NO in the physiopathology of periodontal disease (PD).

Oxidative stress, l-arginine-nitric oxide and arginase pathways in platelets from adolescents with anorexia nervosa.

Anorexia nervosa (AN) is associated with high cardiovascular mortality. Nitric oxide (NO) inhibits platelet function and regulates the cardiovascular homeostasis. The aim of this study was to investigate the l-arginine-NO-GMPc and arginase pathways and oxidative stress in platelets from patients with AN.

Platelet aggregation in arterial hypertension: is there a nitric oxide-urea connection?

1. Systemic arterial hypertension (SAH) is a major independent risk factor for cardiovascular disease. The physiopathology of SAH is multifactorial, complex and remains to be elucidated.

Dengue fever activates the L-arginine-nitric oxide pathway: an explanation for reduced aggregation of human platelets.

In patients with Dengue fever, a viral inflammatory syndrome, haemorrhage is a significant pathological feature, yet the underlying mechanisms remain unclear. Nitric oxide (NO) is an important regulator of platelet function, inhibiting aggregation, recruitment and adhesion to the vascular endothelium. We have investigated whether changes in the activity of the L-arginine-NO pathway in human platelets may account for increased bleeding in patients with Dengue fever.

Depression and cardiovascular disease: role of nitric oxide.

Both depression and cardiovascular disease are major public health problems. Growing evidence shows that depression is a risk factor for the development of coronary artery disease (CAD). However, the exact mechanisms underlying the interplay between depression and CAD remain to be elucidated.

Modulation of the cationic amino acid transport system y+L by surface potential, ouabain and thrombin in human platelets: effects of uremia.

Background: Nitric oxide (NO), a key endogenous mediator involved in the maintenance of platelet function, is synthesized from the amino acid L-arginine. We have shown that L-arginine transport in platelets is rate-limiting for NO synthesis. A disturbance in the L-arginine-NO pathway in platelets was previously described in chronic renal failure (CRF) patients.

Inhibitory effects of endogenous L-arginine analogues on nitric oxide synthesis in platelets: role in platelet hyperaggregability in hypertension.

1. An increase in plasma concentrations of endogenous L-arginine analogues, which are inhibitors of nitric oxide (NO) synthesis, may be involved in platelet activation and the increased risk of thrombosis in essential hypertension. Nitric oxide is synthesised in platelets from the amino acid L-arginine by inducible and constitutive isoforms of NO synthase (NOS), which leads to increased levels of cGMP.