Testosterone deficiency impairs cardiac interfibrillar mitochondrial function and myocardial contractility while inducing oxidative stress.

Introduction: Clinical studies have shown that low levels of endogenous testosterone are associated with cardiovascular diseases. Considering the intimate connection between oxidative metabolism and myocardial contractility, we determined the effects of testosterone deficiency on the two spatially distinct subpopulations of cardiac mitochondria, subsarcolemmal (SSM) and interfibrillar (IFM).

Methods: We assessed cardiac function and cardiac mitochondria structure of SSM and IFM after 12 weeks of testosterone deficiency in male Wistar rats.

Resistance training promotes reduction in Visceral Adiposity without improvements in Cardiomyocyte Contractility and Calcium handling in Obese Rats.

Resistance training (RT) improves the cardiomyocyte calcium (Ca) cycling during excitation-contraction coupling. However, the role of RT in cardiomyocyte contractile function associated with Ca handling in obesity is unclear. Wistar rats were distributed into four groups: control, sedentary obese, control plus RT, and obesity plus RT.

Correction: Testosterone deficiency reduces the effects of late cardiac remodeling after acute myocardial infarction in rats.

[This corrects the article DOI: 10.1371/journal.pone.

Testosterone deficiency reduces the effects of late cardiac remodeling after acute myocardial infarction in rats.

Testosterone is associated with an increased risk of coronary heart disease. This study evaluated cardiac remodeling 60 days after myocardial infarction (MI) in rats with testosterone deficiency. One week after castration, the animals underwent myocardial infarction.

Effects of Chronic Exposure to Mercury on Angiotensin-Converting Enzyme Activity and Oxidative Stress in Normotensive and Hypertensive Rats.

Background: Mercury's deleterious effects are associated with increased cardiovascular risk.

Objective: To determine whether chronic exposure to inorganic mercury increases the activity of angiotensin-converting enzyme and its relationship with oxidative stress in several organs and tissues.

Methods: We studied male Wistar and spontaneously hypertensive rats (SHR) (3-month-old) exposed or not to HgCl2 for 30 days.

Linoleic acid reduces vascular reactivity and improves the vascular dysfunction of the small mesentery in hypertension.

We aimed to investigate the effect of linoleic acid (LA) treatment on the blood pressure and function of mesenteric resistance arteries (MRA) in spontaneous hypertensive rats (SHR). Male SHR were treated daily with LA (15 mg/kg) or vehicle (control) for 15 days. Compared with controls, LA treatment decreased blood pressure and showed the following in MRA: (1) increased lumen and external diameter, (2) decreased wall:lumen ratio and wall thickness, (3) decreased stiffness and (4) less collagen deposition.

MitoQ improves mitochondrial dysfunction in heart failure induced by pressure overload.

Heart failure remains a major public-health problem with an increase in the number of patients worsening from this disease. Despite current medical therapy, the condition still has a poor prognosis. Heart failure is complex but mitochondrial dysfunction seems to be an important target to improve cardiac function directly.

Vascular activation of K channels and Na-K ATPase activity of estrogen-deficient female rats.

The goal of the present study was to evaluate vascular potassium channels and Na-K-ATPase activity in estrogen deficient female rats. Female rats that underwent ovariectomy were assigned to receive daily treatment with placebo (OVX) or estrogen replacement (OVX+E2, 1mg/kg, once a week, i.m.

Chronic iron overload induces functional and structural vascular changes in small resistance arteries via NADPH oxidase-dependent O production.

Iron overload leads to excessive free radical formation and induces cardiovascular dysfunction. Thus, our aim was to investigate the structural and endothelial modulation of vascular tone induced by chronic iron overload in mesenteric arteries. Rats were divided into two groups: the control (vehicle) group and the group treated with iron dextran for 28days (100mg/kg, 5days a week).

Estrogen regulates spatially distinct cardiac mitochondrial subpopulations.

Increased susceptibility to permeability transition pore (mPTP) is a significant concern to decreased cardiac performance in postmenopausal females. The goal of this study was to assess the effects of estrogen deficiency on the two spatially distinct mitochondrial subpopulations from left ventricle: subsarcolemmal mitochondria (SSM) and intermyofibrillar mitochondria (IFM) based on: morphology, membrane potential, oxidative phosphorylation, mPTP and reactive oxygen species production. Female rats (8weeks old) that underwent bilateral ovariectomy were randomly assigned to receive daily treatment with placebo (OVX), estrogen replacement (OVX+E2) and Sham for 60days.

Treatment with high dose of atorvastatin reduces vascular injury in diabetic rats.

Background: Previous reports showed conflicting results regarding the treatment effects of statin on Diabetes mellitus (DM). We investigated how treatment with high dose of atorvastatin affects the impaired vascular function in diabetic rats.

Methods: Atorvastatin (80mg/kg/day, oral gavage, 4 weeks) or its vehicle was administered to male control or streptozotocin (STZ)-induced diabetic rats.

Tributyltin chloride increases phenylephrine-induced contraction and vascular stiffness in mesenteric resistance arteries from female rats.

Tributyltin chloride (TBT) is an organotin compound that reduces estrogen levels in female rats. We aimed to investigate the effects of TBT exposure on vascular tonus and vascular remodelling in the resistance arteries of female rats. Rats were treated daily with TBT (500 ng/kg) for 15 days.

Low mercury concentration produces vasoconstriction, decreases nitric oxide bioavailability and increases oxidative stress in rat conductance artery.

Mercury is an environmental pollutant that reduces nitric oxide (NO) bioavailability and increases oxidative stress, having a close link with cardiovascular diseases, as carotid atherosclerosis, myocardial infarction, coronary heart disease and hypertension. One of the main sites affected by oxidative stress, which develops atherosclerosis, is the aorta. Under acute exposure to low mercury concentrations reactive oxygen species (ROS) production were only reported for resistance vessels but if low concentrations of mercury also affect conductance arteries it is still unclear.

Exposure to low mercury concentration in vivo impairs myocardial contractile function.

Increased cardiovascular risk after mercury exposure has been described but cardiac effects resulting from controlled chronic treatment are not yet well explored. We analyzed the effects of chronic exposure to low mercury concentrations on hemodynamic and ventricular function of isolated hearts. Wistar rats were treated with HgCl₂ (1st dose 4.

Soybean oil increases SERCA2a expression and left ventricular contractility in rats without change in arterial blood pressure.

Background: Our aim was to evaluate the effects of soybean oil treatment for 15 days on arterial and ventricular pressure, myocardial mechanics and proteins involved in calcium handling.

Methods: Wistar rats were divided in two groups receiving 100 microL of soybean oil (SB) or saline (CT) i.m.