title: Glucose and blood pressure lowering effects of Pycnogenol® are inefficient to prevent prolongation of QT interval in experimental diabetic cardiomyopathy.
abstract: Diabetic cardiomyopathy shows ECG alterations related to cardiac repolarization and manifested by increased duration of QT interval. Although the mechanism is unknown, it is widely believed that the reduction of hyperglycaemia might prevent such alterations. To test this hypothesis, we used the standardized extract of French pine bark - Pycnogenol(®) (PYC) with hypoglycaemic and antioxidant properties in 8-9 week old rats with experimentally (streptozotocin) induced diabetes mellitus (DM). PYC was administered orally for 6 weeks in three different doses (10, 20, and 50 mg/kg b.w., resp.). Experimental DM was manifested by hyperglycaemia (four to six-fold increase in plasma glucose concentration; p<0.05) and significantly increased mean arterial blood pressure (by 19%; p<0.05) measured using catheterization of carotid artery in vivo. Both abnormalities were dose-dependently reduced by PYC. In addition, diabetic cardiomyopathy was associated with a significant increase in left ventricular weight to body weight ratio (by 21%; p<0.05) and a significant decrease of the width of cardiomyocytes (by 23%; p<0.05) indicating cardiac edema on the one side, and hypotrophy of cardiomyocytes on the other. Both of these changes were not affected by PYC. Consequently to metabolic and hemodynamic alterations, significant prolongation of QT interval (by 20%; p<0.05) was present in diabetic rats, however, PYC failed to correct it. Conclusively, PYC fails to correct QT prolongation in spite of dose-dependent reduction of glycaemia and high blood pressure in streptozotocin-induced diabetic cardiomyopathy.
authors: Department of Pharmacology and Toxicology, Faculty of Pharmacy, Comenius University, Bratislava, Slovak Republic. jankyova@fpharm.uniba.sk
authors: Stanislava
authors: S
authors: Jankyova
authors: Jana
authors: J
authors: Kmecova
authors: Hana
authors: H
authors: Cernecka
authors: Lucia
authors: L
authors: Mesarosova
authors: Peter
authors: P
authors: Musil
authors: Zuzana
authors: Z
authors: Brnoliakova
authors: Jan
authors: J
authors: Kyselovic
authors: Pavel
authors: P
authors: Babal
authors: Jan
authors: J
authors: Klimas
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001786:Blood Glucose / Q000187:drug effects*; D001794:Blood Pressure / Q000187:drug effects*; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology; D058065:Diabetic Cardiomyopathies / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D005419:Flavonoids / Q000494:pharmacology*; D006352:Heart Ventricles / Q000187:drug effects / Q000473:pathology; D006943:Hyperglycemia / Q000188:drug therapy; D017379:Hypertrophy, Left Ventricular / Q000473:pathology / Q000517:prevention & control; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D008133:Long QT Syndrome / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000473:pathology; D009929:Organ Size / Q000187:drug effects; D010936:Plant Extracts; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000975:Antioxidants; D001786:Blood Glucose; D005419:Flavonoids; D007004:Hypoglycemic Agents; D010936:Plant Extracts; C024070:pycnogenols