Protective effects of nebivolol and reversal of endothelial dysfunction in diabetes associated with hypertension.
This study aims to decipher the potential effects of nebivolol in prevention and/or regression of renal artery dysfunction in diabetes associated with hypertension. Renal arteries were isolated from 80 male mice divided into four experimental groups: (i) group D: diabetics, at 2 months since streptozotocin injection; (ii) group Din: mice that at the initiation of streptozotocin diabetes were treated with 10 mg/kg b.w./day nebivolol for 2 months, to test for the potential prevention of vascular dysfunction; (iii) group Dfin: mice that after 2 months of diabetes were treated daily with 10 mg/kg b.w./day nebivolol for additional 2 months, in order to follow the possible regression of the dysfunction, and (iv) controls (C), age-matched healthy animals. The following measurements were performed: arterial blood pressure, plasma glucose concentration, and the vascular reactivity of the renal arteries in response to noradrenaline (10(-4) M), acetylcholine (10(-4) M) and sodium nitroprusside (10(-4) M). To assess the molecular mechanisms involved in the reactivity of the renal artery, the contribution of mitogen-activated protein kinase (MAP kinase) pathway and of L-type voltage gated Ca(2+) channels (in the contractile response to noradrenaline), of nitric oxide (NO) and Ca(2+) activated K(+) channels (in the endothelium-dependent vasodilator response), and of cGMP (in the endothelium-independent vasodilator response) was examined by exposing the arteries to corresponding inhibitors, and by using myograph and patch-clamp techniques, immunoblotting and NO assays. Results showed that, group D was characterized by hyperglycemia (blood glucose concentration: 136.66 +/- 4.96 mg/dl, a value approximately 65% increased compared to group C) and hypertension (systolic blood pressure: 145.66 +/- 5.96 mm Hg, a value approximately 34% increased compared to group C). Compared to group D, group Din was characterized by diminished blood glucose concentration ( approximately 1.6 fold), reduced systolic and diastolic blood pressure ( approximately 1.3 fold) and heart rate ( approximately 1.6 fold), as well as by increased contractile response of the renal artery to noradrenaline ( approximately 1.84 fold) and of the impeded vasodilator response to acetylcholine ( approximately 1.81 fold) and sodium nitroprusside ( approximately 1.42 fold). Together, these effects demonstrate that administration of 10 mg/kg b.w./day nebivolol at the moment of diabetes induction has preventive effects, ameliorating diabetes dysfunctions. Compared to group D, group Dfin was characterized by diminished glucose concentration ( approximately 1.3 fold), reduced systolic and diastolic blood pressure and heart rate (both approximately 1.2 fold), and by augmentation of contractile response of the renal artery to noradrenaline ( approximately 1.62 fold) and of vasodilator response to acetylcholine ( approximately 1.13 fold) and sodium nitroprusside ( approximately 1.19 fold). These effects assess that administration of 10 mg/kg b.w./day nebivolol after 2 months of diabetes contributes to regression of diabetes-associated dysfunctionalies. Nebivolol influenced the molecular mechanisms involved in renal artery reactivity in diabetic and hypertensive mice: it increased the NO production and endothelial NO synthase (eNOS) protein expression, decreased the expression of proportional, variant protein in L-type calcium channels and Ca(2+) activated K(+) channels, and diminished the MAP kinase activity. The reported data suggest that nebivolol may offer additional vascular protection for treating diabetes associated with hypertension.
Georgescu
Adriana
A
Institute of Cellular Biology and Pathology "N. Simionescu", Bucharest, Romania. adriana.georgescu@icbp.ro
Popov
Doina
D
Dragan
Emanuel
E
Dragomir
Elena
E
Badila
Elisabeta
E
D000818:Animals; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001578:Benzopyrans / Q000627:therapeutic use*; D001786:Blood Glucose / Q000032:analysis; D001794:Blood Pressure / Q000187:drug effects; D020746:Calcium Channels, L-Type / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000150:complications / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D004983:Ethanolamines / Q000627:therapeutic use*; D006973:Hypertension / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000502:physiology; D000068577:Nebivolol; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D024681:Potassium Channels, Calcium-Activated / Q000378:metabolism; D012077:Renal Artery / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D014665:Vasodilator Agents / Q000627:therapeutic use
D000959:Antihypertensive Agents; D001578:Benzopyrans; D001786:Blood Glucose; D020746:Calcium Channels, L-Type; D004983:Ethanolamines; D007004:Hypoglycemic Agents; D024681:Potassium Channels, Calcium-Activated; D014665:Vasodilator Agents; D000068577:Nebivolol; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D020928:Mitogen-Activated Protein Kinases