Sildenafil prevents right ventricular hypertrophy and improves heart rate variability in rats with pulmonary hypertension secondary to experimental diabetes.

Chronic treatment with sildenafil (SILD) is an effective protector on the development of cardiovascular complications of pulmonary hypertension (PH) and diabetes. However, to date, no studies have evaluated the effect of SILD on cardiopulmonary pathophysiology during PH secondary to type 1 diabetes. AIM: The present study aimed to evaluate the beneficial effects of chronic SILD treatment on pulmonary arterial pressure, right ventricular hypertrophy (RVH) and cardiac autonomic dysfunction in rats with PH secondary to diabetes. METODOLOGY: Male Sprague Dawley rats were randomly distributed into the control group (saline), diabetic group (60 mg/kg with streptozotocin), SILD-treated control group (20 mg/kg) and SILD-treated diabetic group. RESULTS: After 8 weeks the type 1 diabetic animals presented PH, endothelial dysfunction of the pulmonary arteries, electrocardiographic alterations, RVH and overexpression of phosphodiesterase type 5 in the heart. In type 1 diabetic animals, SILD treatment prevented the development of PH, endothelial dysfunction and RVH. SILD treatment also prevented alterations in the corrected QT period and heart rate variability and prevented overexpression of phosphodiesterase type 5. CONCLUSION: Our results indicate for the first time that SILD treatment prevents pulmonary arterial endothelial dysfunction, pulmonary hypertension, right ventricular hypertrophy and improves heart rate variability in type 1 diabetic rats.

Aortic dysfunction by chronic cadmium exposure is linked to multiple metabolic risk factors that converge in anion superoxide production.

CONTEXT: The chronic exposure to Cadmium (Cd) constitute an risk to develop hypertension and cardiovascular diseases associated with the increase of oxidative stress. OBJECTIVE: In this study, we investigate the role of metabolic changes produced by exposure to Cd on the endothelial dysfunction via oxidative stress. METHODS: Male Wistar rats were exposed to Cd (32.5-ppm) for 2-months. The zoometry and blood pressure were evaluated, also glucose and lipids profiles in serum and vascular reactivity evaluated in isolated aorta rings. RESULTS: Rats exposed to Cd showed an increase of blood pressure and biochemical parameters similar to metabolic syndrome. Additionally, rats exposed to Cd showed a reduced relaxation in aortic rings, which was reversed after the addition of SOD and apocynin an inhibitor of NADPH. CONCLUSION: The Cd-exposition induced hypertension and endothelial injury by that modifying the vascular relaxation and develop oxidative stress via NADPH oxidase, superoxide and loss nitric oxide bioavailability.

Echocardiographic follow-up to right ventricular modifications in secondary pulmonary hypertension to diabetes in rats.

Clinical studies suggest that diabetes is a risk factor in the development of pulmonary arterial hypertension. The increase in blood pressure in the pulmonary area is characterized by the increase in the afterload and hypertrophy of the right ventricle. The objective of this study was to conduct a longitudinal follow-up of the morphological and functional changes in the right ventricle in a rat model with pulmonary arterial hypertension secondary to diabetes. Male Sprague Dawley rats were randomly divided into a control group (saline solution) and a diabetic group (60 mg/kg with streptozotocin). For 12 weeks, an echocardiography for longitudinal (in vivo) image analysis of the pulmonary pressure was performed at the same time as the evaluation of myocardial remodeling and right ventricular. After this period, the pulmonary pressure was measured by means of a pulmonary artery catheterization, and the presence of hypertrophy was determined by means of the Fulton index. The plasma concentration of brain natriuretic peptide was measured by means of the ELISA technique. It was found that the diabetic rats showed an increase in pressure in the pulmonary arteries, an increase in the Fulton index, and an increase in brain natriuretic peptide. The echocardiographic follow-up showed that the diabetic rats presented an increase in the pulmonary artery from the fourth week, while hypertrophy and right ventricular systolic dysfunction occurred until the twelfth week. In conclusion, pulmonary arterial hypertension induced by experimental diabetes generated hypertrophy and systolic dysfunction of the right ventricle.