delapril and Hypertension--Renovascular

Delapril, a new angiotensin converting enzyme (ACE) inhibitor discovered in the laboratory of Takeda Chemical Industries, Ltd., is the result of drug design based on the structure-activity relationships of ACE inhibitors. Delapril is an antihypertensive agent with a relatively long duration of action and no SH moiety in its structure. Following administration, it is converted into two active metabolites. Delapril effectively lowered blood pressure in 73% of 1,008 patients with hypertension during clinical trials in Japan. Efficacy rates were 73% for essential hypertension, 85% for renal hypertension, and 80% for renovascular hypertension. Excellent hypotensive response was observed in all age groups, from young to elderly patients. Side effects during administration of delapril, based on subjective evidence, were reported in 80 out of the 1,008 cases (7.9%). The main symptoms included orthostatic dizziness (1.7%), dizziness (1.3%), and nausea (1.1%). Dry cough, which has attracted attention in recent years as a side effect of ACE inhibitors, was reported at a low incidence of 1.1%. In a double-blind, controlled study in patients with mild to moderate essential hypertension in which captopril served as a positive control, delapril showed superior hypotensive effect and greater safety. Data derived from the Japan Study Group on Delapril indicate that this ACE inhibitor has excellent hypotensive effects and a high level of safety. It is suitable as a first-line drug in both monotherapy and combined therapy.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Angiotensin-Converting Enzyme Inhibitors; Blood Pressure; Captopril; Female; Heart Rate; Humans; Hypertension; Hypertension, Renal; Hypertension, Renovascular; Indans; Japan; Male; Middle Aged

To investigate the role of vascular angiotensin II (Ang II) in the vascular thickening of one-kidney, one clip (1-K, 1C) hypertensive rats, which show normal plasma renin activity.. The type 1 Ang II receptor antagonist TCV-116 (1 mg/kg per day), the angiotensin converting enzyme (ACE) inhibitor delapril (20 mg/kg per day), hydralazine (20 mg/kg per day) or vehicle were administered to four groups of 1-K, 1C rats aged 6-10 weeks. Vehicle was also given to uninephrectomized rats.. The aortae of 1-K, 1C rats contained significantly higher levels of Ang II than those of uninephrectomized rats and showed hypertrophy, but not hyperplasia of their medial smooth muscle cells. Hypertrophy was estimated by immunohistochemical staining of alpha-actin. Hyperplasia was estimated by DNA content and incorporation of 5-bromo-2'-deoxyuridine. The blood pressure of the 1-K, 1C rats was not affected by either TCV-116 or delapril, even at doses sufficient to induce depressor effects in spontaneously hypertensive rats. However, subdepressor doses of TCV-116 and delapril both significantly reduced the alpha-actin-stained area to 78 and 73%, respectively, of that in the 1-K, 1C rats, whereas a depressor dose of hydralazine did not affect the alpha-actin-stained area. The level of Ang II in the aorta, but not in plasma, was suppressed by delapril but not by hydralazine.. These results suggest strongly that vascular Ang II plays a major role in the development of vascular hypertrophy, independently of plasma Ang II, bradykinin and ACE-independent pathways of Ang II generation, and in the regulation of blood pressure in this normoreninaemic hypertensive model.

Topics: Actins; Angiotensin II; Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; Aorta, Thoracic; Benzimidazoles; Biphenyl Compounds; DNA; Hydralazine; Hypertension, Renovascular; Hypertrophy; Indans; Male; Muscle, Smooth, Vascular; Rats; Rats, Wistar; Tetrazoles