delapril and Body-Weight

In previous articles, we have shown that the combination of the angiotensin-converting enzyme (ACE) inhibitor delapril (12 mg/kg/day) and the diuretic indapamide (1 mg/kg/ day) was able to prolong the life span significantly in salt-loaded stroke-prone spontaneously hypertensive rats (SHRsp). Because this finding was partly dependent on the antagonism of salt-loading effects by pharmacologic induction of diuresis, which prevented any increase in blood pressure values, we decided to evaluate whether lower doses of the combination could be equally protective without changing the progression of hypertension. Thus, we studied several treatments with progressively lower doses of delapril (6, 3, or 1.5 mg/kg/day) combined with indapamide (0.5, 0.25, or 0.125 mg/kg/day) or hydrochlorothiazide (2.5, 1.25, or 0.625 mg/kg/day) in salt-loaded SHRsp. Salt-loaded untreated animals were considered to be the control group. In agreement with previous experiments, control rats reached 50% mortality approximately 7 weeks after the beginning of salt loading. The combination of delapril and hydrochlorothiazide at the two lowest doses was not able to delay animal death significantly, whereas treatment with delapril and indapamide at the lowest dose was effective (50% survival rate, 15 weeks). The groups treated with the highest dose of delapril and hydrochlorothiazide or with the intermediate or highest dose of delapril and indapamide did not reach 50% mortality by the end of the experiment, at 44 weeks of treatment (i.e., when animals reached age 1 year). Only the highest delapril and indapamide doses were able to increase diuresis, but for a relatively short period. None of the treatments was able to lower or control blood pressure levels adequately. Therefore, blood pressure levels by themselves were not predictive of rat mortality. In contrast, the maximal value of proteinuria in the weeks preceding death was inversely correlated with the survival time. In conclusion, this study shows that low doses of an ACE inhibitor in combination with a diuretic can be effectively protective in a model of severe hypertension, independent of any change in blood pressure levels.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Pressure; Body Weight; Diuretics; Dose-Response Relationship, Drug; Drug Therapy, Combination; Electrolytes; Hydrochlorothiazide; Hypertension; Indans; Indapamide; Male; Proteinuria; Rats; Rats, Inbred SHR

The renin-angiotensin system is an important modulator of arterial blood pressure and inhibitors of the angiotensin-converting enzyme (ACE-Is) and are currently used in the treatment of hypertension. The pleiotropic actions exerted by angiotensin II (AngII) on the functionality of the vessel wall may have pro-atherosclerotic outcomes; evidence for an anti-atherosclerotic effect of ACE-Is has been presented and an antioxidant effect has been attributed to thiol-containing ACE-Is, like Captopril. The present study has been undertaken to investigate the effect of Delapril, a lipophilic ACE-I, on the development of atherosclerosis in cholesterol-fed rabbits. While it did not correct hyperlipidemia, Delapril dose dependently inhibited the development of atherosclerosis, expressed as aortic area covered by lesions (23.3+/-4.1, 21.3+/-2.4 and 18.5+/-3.3% with Delapril at the daily dose of 5, 10 and 20 mg/kg, respectively, versus 38.2%+/-6.4 for control animals) and its effect was similar to that of Captopril (14.5+/-5.1% at the daily dose of 25 mg/kg). Furthermore, Delapril partially and dose dependently restored endothelium-dependent relaxation, which is impaired in vessels from hypercholesterolemic animals (51.80+/-12.18, 59.74+/-5.16, 69.13+/-8.70 maximal percent relaxation versus 48.26+/-3.05% for the untreated control and 67.67+/-6.72% for Captopril-treated animals). An antioxidant mechanism is unlikely to explain this data, since Delapril does not contain thiol groups. These observations suggest that Delapril may represent an effective pharmacological approach for the treatment of atherosclerosis during its early phases.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Aorta, Abdominal; Aorta, Thoracic; Arteriosclerosis; Body Weight; Captopril; Cholesterol; Cholesterol, Dietary; Cholesterol, HDL; Data Interpretation, Statistical; Diet, Atherogenic; Disease Models, Animal; Disease Progression; Dose-Response Relationship, Drug; Endothelium, Vascular; Hypercholesterolemia; Indans; Male; Nitric Oxide; Nitroglycerin; Norepinephrine; Rabbits; Triglycerides; Vasoconstrictor Agents; Vasodilation; Vasodilator Agents

The effects of long-term oral administration of delapril (CAS 83435-67-0), indapamide (CAS 26807-65-8) and their combination on the occurrence of stroke and on mortality were investigated in young salt-loaded stroke-prone spontaneously hypertensive rats (SHRsp) for 31 weeks of treatment (8th-39th week of age) and up to 8 weeks thereafter. Body weight and saline consumption were investigated at regular intervals and cerebrovascular lesions, renal and heart weight were assessed after sacrifice. Untreated SHRsp served as controls. About 50% of control animals died within 6 weeks of saline administration and in 56% of surviving animals cerebral lesions were present at sacrifice, while no death and no cerebral lesions were observed in animals drinking saline, to which delapril, indapamide and their combination had been added, up to the end of treatment. This protective effect was maintained even in the withdrawal period. All treatments induced a highly significant (p < 0.001) reduction of heart weight/body weight and kidney weight/body weight ratios.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Body Weight; Cerebrovascular Disorders; Diuretics; Drug Interactions; Hemodynamics; Hypertension; Indans; Indapamide; Longevity; Male; Organ Size; Rats; Rats, Inbred SHR; Sodium, Dietary

1. Stroke-prone spontaneously hypertensive rats (SHRsp) have been used widely to test agents putatively capable of vascular protection. These animals present an accelerated time course of hypertension and a reduced life-span. When fed a high-sodium diet from the eighth week of life, a further acceleration in blood pressure increase is obtained, and rats start to die after 5 weeks of diet as a consequence of cerebral haemorrhage. In this model, angiotensin-converting enzyme (ACE) inhibitors were repeatedly proved to prevent vascular lesions and death. Notably, this effect was independent of any hypotensive effect. On the contrary, diuretics were shown not to be equally effective. A combination of ACE inhibitors and diuretics, although known to have synergistic effects in the therapy of hypertension, has never previously been tested. 2. Our aim was to study the effects of long-term treatment with the ACE inhibitor delapril (12 mg day-1 kg-1), the thiazide-like diuretic indapamide (1 mg day-1 kg-1), and their combination (12 and 1 mg day-1 kg-1 respectively), on the survival of SHRsp rats fed a high-sodium diet from the eighth week of life onwards. The effects of the treatments on blood pressure, body weight, food and fluid intake, diuresis, proteinuria and the appearance of lesion signs and death were assessed weekly. When control rats reached 50% mortality, they were killed, together with some drug-treated rats, to compare lesions in brain and kidney. The other drug-treated rats continued treatments until 50% mortality was reached in two treatment groups. 3. All drug treatments were able to delay death significantly when compared with control rats, which reached 50% mortality after 6 weeks of salt loading. This event was preceded by a highly significant increase in proteinuria, diuresis and fluid intake that took place 3 weeks after the increase in blood pressure over the initial range. In delapril- or indapamide-treated SHRsp these changes were never seen, even when animals started to die. In the combination-treated group, a significant increase (P < 0.01) in fluid intake and diuresis, but not proteinuria, was observed from the third week of treatment onwards. 4. Treatment with delapril or indapamide did not block the progressive increase in blood pressure as observed in control animals. However, the increase in blood pressure was markedly retarded with respect to control rats. At variance with this, in combination-treated animals blood pressure levels we

Topics: Analysis of Variance; Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; Blood Pressure; Body Weight; Brain; Cerebrovascular Disorders; Diuresis; Drug Therapy, Combination; Indans; Indapamide; Kidney; Male; Proteinuria; Rats; Rats, Inbred SHR; Sodium, Dietary; Time Factors

Angiotensin II plays an important role in neointimal formation after vascular injury. Our objectives were 1) to investigate the difference between angiotensin converting enzyme inhibitors (captopril, delapril) and an angiotensin II subtype 1 (AT1) receptor antagonist (DuP753) in suppressing neointimal proliferation; and 2) to investigate the antiproliferative effects of these drugs given topically to the injured vessels. All these treatments effectively prevented neointimal formation (p < 0.01). Even a single topical application of either type of drug with F127 pluronic gel to be injured vessel after ballooning is found to be significantly effective probably due to the inhibition of smooth muscle cell migration (p < 0.01). Multiple systemic application of angiotensin converting enzyme inhibitors was more effective than that of DuP753 at the same blood pressure level. The effectiveness of topical application of these drugs suggests clinical usefulness after angioplasty or vascular surgery.

Topics: Administration, Topical; Angiotensin Receptor Antagonists; Animals; Biphenyl Compounds; Blood Pressure; Body Weight; Captopril; Carotid Arteries; Carotid Artery Injuries; Catheterization; Cell Division; Embolization, Therapeutic; Imidazoles; Indans; Losartan; Male; Muscle, Smooth, Vascular; Rats; Rats, Wistar; Tetrazoles

Regulation of the gene expression of type-1 angiotensin II receptor (AT1) by treatment with manidipine, a calcium channel blocker, or delapril, an angiotensin converting enzyme inhibitor, for one week was assessed in the adrenal gland, heart, kidney, and brain from spontaneously hypertensive rats (SHR). Tissue AT1 receptor messenger RNA (mRNA) content was measured by reverse transcriptase-polymerase chain reaction. Treatment with manidipine (3 mg/kg/day) or delapril (30 mg/kg/day) lowered systolic blood pressure (SBP) significantly (p < 0.01) (delta SBP; -73 mmHg or -67 mmHg, respectively). Although delapril markedly increased plasma renin activity (PRA), manidipine did not alter PRA. AT1 receptor mRNA content in the adrenal gland was significantly (p < 0.01) decreased by treatment with manidipine or delapril. In contrast, cardiac AT1 receptor mRNA content was significantly (p < 0.01) increased by treatment with either agent. There was no significant change in renal and brain AT1 receptor mRNA contents. These findings suggest that although the expression of AT1 receptor gene depends on the circulating renin-angiotensin system (RAS), it is regulated independently in a tissue-specific manner via the local RAS in each tissue of SHR.

Topics: Adrenal Glands; Angiotensin-Converting Enzyme Inhibitors; Animals; Autoradiography; Base Sequence; Blood Pressure; Body Weight; Brain; Calcium Channel Blockers; Dihydropyridines; Gene Expression Regulation; Heart Rate; Hypertension; Indans; Kidney; Male; Molecular Sequence Data; Myocardium; Nitrobenzenes; Piperazines; Polymerase Chain Reaction; Rats; Rats, Inbred SHR; Receptors, Angiotensin; Renin; RNA, Messenger

To study the effect of antihypertensive therapy on the regulation of renin gene expression, the levels of tissue renin messenger RNA (mRNA) were measured after treatment with a calcium channel blocker (manidipine hydrochloride 3 mg/kg/day) or an angiotensin-converting enzyme inhibitor (delapril hydrochloride 30 mg/kg/day), administered orally for 1 week, in spontaneously hypertensive rats (SHR). Male SHR, aged 15 weeks old, were used in this study (n = 5 per group). Control rats were administered the vehicle alone. Tissue total RNA was isolated from kidney, adrenal gland, heart, and brain tissue, and tissue RNA was reverse-transcribed to complementary DNA (cDNA), which was specifically amplified by polymerase chain reaction with labeled-primers for the rat renin gene. The radioactivity of the cDNA products was measured directly. Although delapril increased plasma renin activity (PRA) about 5-fold compared with the control group, manidipine did not change PRA. The kidney renin mRNA content was increased about 6-fold by treatment with delapril. Manidipine and delapril significantly decreased the renin mRNA content in the heart (p < 0.01 and p < 0.05, respectively). The level of renin mRNA in the adrenal gland and brain tissues was not significantly changed by treatment with either drug. These results suggest that tissue renin gene expression in SHR is regulated by a tissue-specific process independent of the circulating renin-angiotensin system.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Autoradiography; Base Sequence; Blood Pressure; Body Weight; Calcium Channel Blockers; Dihydropyridines; Gene Expression; Gene Expression Regulation; Heart Rate; Hypertension; Indans; Kidney; Male; Molecular Sequence Data; Nitrobenzenes; Piperazines; Polymerase Chain Reaction; Rats; Rats, Inbred SHR; Renin; RNA, Messenger