Chronic (-)-epicatechin improves vascular oxidative and inflammatory status but not hypertension in chronic nitric oxide-deficient rats.

Abstract

The present study analysed the effects of the flavanol (-)-epicatechin in rats after chronic inhibition of NO synthesis with NG-nitro-L-arginine methyl ester (L-NAME), at doses equivalent to those achieved in the studies involving human subjects. Wistar rats were randomly divided into four groups: (1) control-vehicle, (2) L-NAME, (3) L-NAME-epicatechin 2 (L-NAME-Epi 2) and (4) L-NAME-epicatechin 10 (L-NAME-Epi 10). Rats were daily given by oral administration for 4 weeks: vehicle, (-)-epicatechin 2 or 10 mg/kg. Animals in the L-NAME groups daily received L-NAME 75 mg/100 ml in drinking-water. The evolution in systolic blood pressure and heart rate, and morphological and plasma variables, proteinuria, vascular superoxide, reactivity and protein expression at the end of the experiment were analysed. Chronic (-)-epicatechin treatment did not modify the development of hypertension and only weakly affected the endothelial dysfunction induced by L-NAME but prevented the cardiac hypertrophy, the renal parenchyma and vascular lesions and proteinuria, and blunted the prostanoid-mediated enhanced endothelium-dependent vasoconstrictor responses and the cyclo-oxygenase-2 and endothelial NO synthase (eNOS) up-regulation. Furthermore, (-)-epicatechin also increased Akt and eNOS phosphorylation and prevented the L-NAME-induced increase in systemic (plasma malonyldialdehyde and urinary 8-iso-PGF2α) and vascular (dihydroethidium staining, NADPH oxidase activity and p22phox up-regulation) oxidative stress, proinflammatory status (intercellular adhesion molecule-1, IL-1β and TNFα up-regulation) and extracellular-signal-regulated kinase 1/2 phosphorylation. The present study shows for the first time that chronic oral administration of (-)-epicatechin does not improve hypertension but reduced pro-atherogenic pathways such as oxidative stress and proinflammatory status of the vascular wall induced by blockade of NO production.

• Authors: Manuel Gómez-Guzmán, Rosario Jiménez, Manuel Sánchez, Miguel Romero, Francisco O'Valle, Rocío Lopez-Sepulveda, Ana María Quintela, Pilar Galindo, María José Zarzuelo, Elvira Bailón, Eva Delpón, Francisco Perez-Vizcaino, Juan Duarte
• Journal: The British journal of nutrition (Br J Nutr) Vol. 106 Issue 9 Pg. 1337-48 (Nov 2011) ISSN: 1475-2662 [Electronic] England
• PMID: 21910946 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Inflammation Mediators
• Plant Extracts
• Prostaglandins
• Nitric Oxide
• Catechin
• Nitric Oxide Synthase
• Cyclooxygenase 2
• NG-Nitroarginine Methyl Ester

Topics

• Animals
• Atherosclerosis (prevention & control)
• Blood Pressure (drug effects)
• Catechin (administration & dosage, pharmacology, therapeutic use)
• Cyclooxygenase 2 (blood)
• Endothelium, Vascular (drug effects, physiopathology)
• Hypertension
• Hypertrophy
• Inflammation (drug therapy)
• Inflammation Mediators (blood)
• Kidney (drug effects, pathology)
• MAP Kinase Signaling System (drug effects)
• Male
• Myocardium (pathology)
• NG-Nitroarginine Methyl Ester
• Nitric Oxide (antagonists & inhibitors, deficiency)
• Nitric Oxide Synthase (metabolism)
• Oxidative Stress (drug effects)
• Phosphorylation
• Phytotherapy
• Plant Extracts (administration & dosage, pharmacology, therapeutic use)
• Prostaglandins (metabolism)
• Proteinuria (drug therapy)
• Rats
• Rats, Wistar
• Up-Regulation
• Vascular Diseases (drug therapy, metabolism, pathology, physiopathology)
• Vasoconstriction (drug effects)