enalapril and Cerebrovascular-Disorders

Isolated systolic hypertension occurs in about 15% of people aged 60 years or older. In 1989, the European Working Party on High Blood Pressure in the Elderly investigated whether active treatment could reduce cardiovascular complications of isolated systolic hypertension. Fatal and non-fatal stroke combined was the primary endpoint.. All patients (> 60 years) were initially started on masked placebo. At three run-in visits 1 month apart, their average sitting systolic blood pressure was 160-219 mm Hg with a diastolic blood pressure lower than 95 mm Hg. After stratification for centre, sex, and previous cardiovascular complications, 4695 patients were randomly assigned to nitrendipine 10-40 mg daily, with the possible addition of enalapril 5-20 mg daily and hydrochlorothiazide 12.5-25.0 mg daily, or matching placebos. Patients withdrawing from double-blind treatment were still followed up. We compared occurrence of major endpoints by intention to treat.. At a median of 2 years' follow-up, sitting systolic and diastolic blood pressures had fallen by 13 mm Hg and 2 mm Hg in the placebo group (n = 2297) and by 23 mm Hg and 7 mm Hg in the active treatment group (n = 2398). The between-group differences were systolic 10.1 mm Hg (95% CI 8.8-11.4) and diastolic, 4.5 mm Hg (3.9-5.1). Active treatment reduced the total rate of stroke from 13.7 to 7.9 endpoints per 1000 patient-years (42% reduction; p = 0.003). Non-fatal stroke decreased by 44% (p = 0.007). In the active treatment group, all fatal and non-fatal cardiac endpoints, including sudden death, declined by 26% (p = 0.03). Non-fatal cardiac endpoints decreased by 33% (p = 0.03) and all fatal and non-fatal cardiovascular endpoints by 31% (p < 0.001). Cardiovascular mortality was slightly lower on active treatment (-27%, p = 0.07), but all-cause mortality was not influenced (-14%; p = 0.22).. Among elderly patients with isolated systolic hypertension, antihypertensive drug treatment starting with nitrendipine reduces the rate of cardiovascular complications. Treatment of 1000 patients for 5 years with this type of regimen may prevent 29 strokes or 53 major cardiovascular endpoints.

Topics: Aged; Antihypertensive Agents; Blood Pressure; Calcium Channel Blockers; Cerebrovascular Disorders; Double-Blind Method; Drug Therapy, Combination; Enalapril; Female; Follow-Up Studies; Humans; Hydrochlorothiazide; Hypertension; Male; Morbidity; Nitrendipine; Time Factors

The incidence of thromboembolism and the benefit of anticoagulation in congestive heart failure are controversial.. The data base provided by the Veterans Affairs Vasodilator-Heart Failure Trials (V-HeFT I and II) was examined retrospectively to address these issues. In V-HeFT I, 642 men with heart failure were followed an average of 2.28 years, providing 1,464 patient-years of follow-up. In V-HeFT II, 804 men were followed an average of 2.56 years, with 2,061 patient-years of follow-up. Mean left ventricular ejection fraction was 30% in V-HeFT I and 29% in V-HeFT II: Functional capacity was at the interface of classes II and III with a peak exercise oxygen consumption of 14.7 mL.kg-1 x min-1 in V-HeFT I and 13.7 mL.kg-1 x min-1 in V-HeFT II: Warfarin and antiplatelet agents were administered at the discretion of individual investigators. The incidence of all thromboembolic events during 1,068 patient-years without warfarin in V-HeFT I was 2.7/100 patient-years and during 1,188 patient-years in V-HeFT II was 2.1/100 patient-years and was not reduced in patients treated with warfarin. Patients experiencing events had a lower peak exercise oxygen consumption (p < 0.03 in V-HeFT I and p < 0.001 in V-HeFT II) and a lower mean ejection fraction (p = 0.10 in V-HeFT I and p = 0.07 in V-HeFT II). Atrial fibrillation was not associated with an increased risk of thromboembolic events.. The incidence of thromboembolism and stroke in class II or III congestive heart failure is not high and may not be significantly reduced with warfarin treatment. Routine use of anticoagulants in patients with heart failure may not be justified.

Topics: Cerebrovascular Disorders; Drug Therapy, Combination; Enalapril; Heart Failure; Humans; Hydralazine; Incidence; Isosorbide Dinitrate; Male; Middle Aged; Platelet Aggregation Inhibitors; Prazosin; Thromboembolism; Warfarin

Syst-Eur is a multicenter placebo-controlled outcome trial designed by the European Working Party on High Blood Pressure in the Elderly to investigate the effect of antihypertensive treatment on the incidence of stroke in elderly patients with isolated systolic hypertension (ISH). Eligible patients must be at least 60 years old and have a systolic blood pressure averaging 160-219 mm Hg with a diastolic blood pressure less than 95 mm Hg. The present paper is an interim report on the first 316 patients randomized into this trial. The placebo (n = 170) and active treatment (n = 146) groups were similar at randomization with respect to age (73 +/- 8 years; mean +/- SD), sitting blood pressure (178 +/- 12 mm Hg systolic; 85 +/- 7 mm Hg diastolic), percentage of men (34%), and percentage of patients with cardiovascular complications (29%). After randomization blood pressure fell more (p less than 0.001) in patients on active treatment than in those in the placebo group (19 +/- 20 mm Hg systolic; 6 +/- 10 mm Hg diastolic vs. 7 +/- 19 and 1 +/- 10 mm Hg for sitting blood pressure). This first interim report on the Syst-Eur trial demonstrates that a multinational trial in elderly patients with ISH is feasible and that a significant blood pressure difference between the two treatment groups can be achieved and maintained. New centers are being recruited in order to randomize a total of 3,000 patients.

Topics: Aged; Aged, 80 and over; Antihypertensive Agents; Blood Pressure; Cerebrovascular Disorders; Double-Blind Method; Enalapril; Europe; Female; Follow-Up Studies; Humans; Hydrochlorothiazide; Hypertension; Male; Nitrendipine; Systole

Vascular factors have been shown to be associated with increased risk of dementia. However, clinical trials have so far been unsuccessful, suggesting new approaches are needed. The aim of this study was to use population-based real-world data to investigate risk factors and preventive factors for dementia, including the effects of traditional Chinese medicine (TCM).. This is a retrospective cohort study using LHID2000, a dataset randomly selected from Taiwan's National Health Insurance Research Database. Subjects with occlusion and stenosis of precerebral and cerebral arteries, cerebral atherosclerosis without mention of cerebral infarction, and transient cerebral ischemia were included. Subjects with dementia at baseline were excluded. The primary endpoint was dementia. Data for demographic and clinical comorbid status and treatments administered at baseline in 2000 and at the end of follow-up in 2013 were included.. A total of 4,207 subjects with cerebral vascular disease and no cognitive impairment were included, of whom 392 converted to dementia during an average 5.15-year (SD: 3.79) follow-up. Depression (adjusted HR: 1.54, 95% confidence interval [CI]: 1.13-2.09), osteoporosis (adjusted HR: 1.34, 95% CI: 1.04-1.74), and the use of enalapril (adjusted HR: 1.37, 95% CI: 1.09-1.73) were risk factors for dementia, while nitroglycerin (adjusted HR: 0.67, 95% CI: 0.53-0.85) was a protecting factor, in subjects with cerebrovascular diseases without mention of cerebral infarction. In total, statins were shown to be associated with decreased risk of dementia (HR: 0.73, 95% CI: 0.59-0.91); however, no one statin subtype or TCM had such an effect.. Depression, osteoporosis, and the use of enalapril were associated with a higher risk of dementia, while nitroglycerin might be a protecting factor for dementia, in subjects with cerebrovascular diseases without mention of cerebral infarction.

Topics: Cerebral Infarction; Cerebrovascular Disorders; Dementia; Enalapril; Humans; Nitroglycerin; Osteoporosis; Retrospective Studies; Risk Factors; Taiwan

The co-administration of angiotensin converting enzyme inhibitors (ACEi) and angiotensin II (AngII) receptor blockers (ARB) that bind angiotensin type 1 receptors (AT1R) may protect from Alzheimer's disease (AD) better than each treatment taken alone. We tested the curative potential of the non brain-penetrant ACEi enalapril (3 mg/kg/day) administered for 3 months either alone or in combination with the brain penetrant ARB losartan (10 mg/kg/day) in aged (∼15 months) transgenic mice overexpressing a mutated form of the human amyloid-β protein precursor (AβPP, thereafter APP mice). We studied cerebrovascular function, protein levels of oxidative stress markers (superoxide dismutases SOD1, SOD2 and the NADPH oxidase subunit p67phox), amyloid-β (Aβ) pathology, astrogliosis, cholinergic innervation, AT1R and angiotensin IV receptor (AT4R) levels, together with cognitive performance. Both treatments normalized cerebrovascular reactivity and p67phox protein levels, but they did not reduce the cerebrovascular levels of SOD1. Combined treatment normalized cerebrovascular SOD2 levels, significantly attenuated astrogliosis, but did not reduce the increased levels of cerebrovascular AT1R. Yet, combined therapy enhanced thioflavin-S labeled Aβ plaque burden, a tendency not significant when Aβ1 - 42 plaque load was considered. None of the treatments rescued cognitive deficits, cortical AT4R or cholinergic innervation. We conclude that both treatments normalized cerebrovascular function by inhibiting the AngII-induced oxidative stress cascade, and that the positive effects of the combined therapy on astrogliosis were likely due to the ability of losartan to enter brain parenchyma. However, enalapril did not potentiate, and may even dampen, the reported cognitive benefits of losartan, raising caution when selecting the most appropriate antihypertensive therapy in AD patients.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Amyloidosis; Analysis of Variance; Animals; Antihypertensive Agents; Cerebrovascular Disorders; Cholinesterases; Disease Models, Animal; Drug Combinations; Enalapril; Female; Glial Fibrillary Acidic Protein; Humans; Losartan; Male; Maze Learning; Memory Disorders; Mice; Mice, Transgenic; Mutation

We examined the functional and structural microcirculatory alterations in the brain, skeletal muscle and myocardium of non-diabetic spontaneously hypertensive rats (SHR) and diabetic SHR (D-SHR), as well as the effects of long-term treatment with the angiotensin AT1-receptor antagonist olmesartan and the angiotensin-converting enzyme inhibitor enalapril. Diabetes was experimentally induced by a combination of a high-fat diet with a single low dose of streptozotocin (35 mg/kg, intraperitoneal injection). D-SHR were orally administered with olmesartan (5 mg/kg/day), enalapril (10 mg/kg/day) or vehicle for 28 days, and compared with vehicle-treated non-diabetic SHR or normotensive non-diabetic Wistar-Kyoto rats. The cerebral and skeletal muscle functional capillary density of pentobarbital-anesthetized rats was assessed using intravital fluorescence videomicroscopy. Chronic treatment with olmesartan or enalapril significantly lowered blood pressure and reversed brain functional capillary rarefaction. Brain oxidative stress was reduced to non-diabetic control levels in animals treated with olmesartan or enalapril. Histochemical analysis of the structural capillary density showed that both olmesartan and enalapril increased the capillary-to-fiber ratio in skeletal muscle and the capillary-to-fiber volume density in the left ventricle. Olmesartan and enalapril also prevented collagen deposition and the increase in cardiomyocyte diameter in the left ventricle. Our results suggest that the association between hypertension and diabetes results in microvascular alterations in the brain, skeletal muscle and myocardium that can be prevented by chronic blockade of the renin-angiotensin system.

Topics: Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; Arterial Pressure; Blood Glucose; Brain; Capillaries; Cerebrovascular Circulation; Cerebrovascular Disorders; Coronary Circulation; Diabetes Mellitus, Experimental; Diabetic Angiopathies; Diet, High-Fat; Enalapril; Heart Ventricles; Hypertension; Imidazoles; Insulin; Leukocyte Rolling; Male; Microcirculation; Microscopy, Fluorescence; Microscopy, Video; Muscle, Skeletal; Oxidative Stress; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Renin-Angiotensin System; Streptozocin; Tetrazoles

Stroke-prone spontaneously hypertensive rats (SHRSP), subjected to high NaCl intake, show severe hypertension, organ damage, and early death. Preventive treatment with an angiotensin-converting enzyme (ACE) inhibitor is known to reduce mortality. Previously we found that proteinuria always precedes cerebral edema in SHRSP. Hence, in this study ACE inhibition was started later, ie, directly after manifestation of either proteinuria or cerebral edema.. SHRSP were subjected to 1% NaCl intake. Group 1 served as a control. In group 2 early-onset treatment with the ACE inhibitor enalapril was initiated after proteinuria was >40 mg/d. In group 3 late-onset ACE inhibition was started after the first observation of cerebral edema with T2-weighted MRI. Cerebral edema was expressed as the percentage of pixels with an intensity above a defined threshold.. In controls median survival was 54 days (range, 32 to 80 days) after start of salt loading. The terminal level of cerebral edema was 19.0+/-3.0%. Under early-onset enalapril, median survival increased to 320 days (range, 134 to 368 days; P<0.01 versus group 1). Cerebral edema was prevented in all but 1 rat. Systolic blood pressure was slightly and transiently reduced at day 14. Proteinuria was markedly reduced (52+/-7 versus 190+/-46 mg/d in group 1 at day 7; P<0.05). Under late-onset enalapril, median survival was 264 days (range, 154 to 319 days; P<0.01 versus group 1). Cerebral edema decreased to baseline levels (9.6+/-2.9 at day 0 to 3.4+/-0.5% at day 3; (P<0.05). Ultimately cerebral edema reoccurred in 6 of the 8 rats. SBP decreased slightly at day 7 only. Proteinuria decreased from 283+/-27 at day 0 to 116+/-22 mg/d at day 7 (P<0.05). Complete remission of the original locus of cerebral edema was confirmed histologically.. In SHRSP with proteinuria, treatment with an ACE inhibitor both prevented the development of cerebral edema and reduced manifest cerebral edema and proteinuria. Survival was markedly prolonged. These findings support the use of ACE inhibition for treatment in hypertensive encephalopathy.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Body Weight; Brain Edema; Cerebrovascular Disorders; Drinking; Eating; Enalapril; Magnetic Resonance Imaging; Male; Proteinuria; Rats; Rats, Inbred SHR; Sodium, Dietary; Survival Analysis

Recently, we have shown that chronic administration of N-Nitro-L-Arginine Methyl Ester (L-NAME, an inhibitor of nitric oxide synthase) precipitates stroke in stroke-prone spontaneously hypertensive rats (SHRSP). Enalapril maleate, an angiotensin converting enzyme inhibitor was shown to delay the onset of such stroke. In the present study, five groups of 4-week-old SHRSP were used. Three groups of SHRSP were made diabetic using streptozotocin (100 mg/kg i.p.). One week later, the SHRSP from groups I (non-diabetic) and III (diabetic) chronically received L-NAME (0.5 g/L) in saline as drinking water. Two SHRSP groups, II (non-diabetic) and IV (diabetic) received L-NAME (0.5 g/L) and enalapril maleate (20 mg/L) in saline as drinking water. Control SHRSP (group C; diabetic) received only saline to drink. SHRSP groups I and III developed stroke in 10+/-2 and 11+/-2 days, respectively. The average stroke-free period in groups II and IV was 19+/-2 and 28+/-2 days, respectively. Protective effect of streptozotocin-induced diabetes disappeared when SHRSP drinking L-NAME and enalapril, concurrently received subcutaneous injections of insulin (2 units daily per 100 g rat). Present data suggest that experimental diabetes delays the onset of L-NAME-induced stroke in SHRSP only in the absence of angiotensin converting enzyme activity. In addition, diabetes-induced enhancement of stroke-protective effect of enalapril appears to be independent of reduction in mean and systolic blood pressures.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Cerebrovascular Disorders; Diabetes Mellitus, Experimental; Enalapril; Endothelin-1; Hypertension; Male; NG-Nitroarginine Methyl Ester; Nitric Oxide; Rats; Rats, Inbred SHR; Streptozocin; Weight Gain

Valsartan ((S)-N-valeryl-N-¿[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl¿ valine, CAS 137862-53-4, CGP 48933), a non-peptide angiotensin II type 1 receptor antagonist, or enalapril was administered to spontaneously hypertensive rats stroke-prone (SHR-SP) for 1 year from 8 weeks to 56 weeks of age under a normal diet without saline load. During 48 weeks, control rats showed increase in systolic blood pressure from 180 to 250 mmHg accompanying stroke-related behaviour, cardiac and aortic hypertrophy, hyperreactive contractility of mesenteric vascular beds, proteinuria, high water turnover and death. Valsartan at 3, 10 and 30 mg/kg/d p.o. and enalapril at 1 and 10 mg/kg/d p.o suppressed the increase in blood pressure dose-dependently. Systolic blood pressure was steadily controlled to around 180 mmHg at the highest dose of either drug throughout the study. In proportion to the antihypertensive action of the drugs, end-organ damage was prevented. During 1-year administration, effects of enalapril and valsartan were much the same, indicating the clinical usefulness of valsartan being comparable to enalapril.

Topics: Angiotensin Receptor Antagonists; Animals; Antihypertensive Agents; Aorta, Thoracic; Blood Pressure; Body Weight; Cardiomegaly; Cerebrovascular Disorders; Enalapril; Heart Rate; Hypertension; Male; Mesentery; Muscle Contraction; Organ Size; Rats; Rats, Inbred SHR; Rats, Wistar; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Tetrazoles; Valine; Valsartan

The effects of chronic treatment with an angiotensin II receptor antagonist, candesartan cilexetil (TCV-116, 0.1, 1, 10 mg/kg), and an angiotensin converting enzyme inhibitor, enalapril maleate (enalapril, 10 mg/kg), on the development of end-organ damage were examined in stroke-prone spontaneously hypertensive rats (SHRSP). The control SHRSP developed severe hypertension with stroke signs and increased urinary protein excretion. TCV-116 (0.1 mg/kg) reduced the stroke incidence and urinary protein excretion without affecting the blood pressure. TCV-116 (1 and 10 mg/kg) and enalapril reduced blood pressure, the stroke incidence, the urinary indices and left ventricular weight. Circulating renin-angiotensin system (RAS) and renal renin mRNA expression were significantly accelerated or tended to be accelerated in the control SHRSP with end-organ damages. A low dose of TCV-116 tended to reduce the RAS indices in plasma by improving the damages, whereas a high dose (10 mg/kg) increased them by the reflexes with blocking RAS. The present results indicate that chronic All blockade reduces the increase in blood pressure, end-organ damages and RAS related to the damages in SHRSP.

Topics: Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Angiotensinogen; Angiotensins; Animals; Antihypertensive Agents; Benzimidazoles; Biphenyl Compounds; Blood Pressure; Cardiomegaly; Cerebrovascular Disorders; Enalapril; Hypertension; Kidney; Male; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptors, Angiotensin; Renin; RNA, Messenger; Tetrazoles

The protective effects of ME3221, 3-methoxy-2,6-dimethyl-4-[[2'-(1H-tetrazol-5-yl)-1,1'-biphenyl-4-y l]methoxy] pyridine, on aged (32-week-old) stroke-prone spontaneously hypertensive rats (SHRSP) were studied following long-term (for 8 months) oral administration. At a dose of 10 mg/kg/day, ME3221 suppressed the mortality and the hypertensive complications observed in control SHRSP: cerebral apoplexy (hemorrhage, and spongeform and malacia in the cerebral cortex), increased proteinuria, and total N-acetyl-beta-D-glucosaminidase activity, and cardiac hypertrophy and pleural effusion. The protective activity of ME3221, a surmountable angiotensin AT1-receptor antagonist, was comparable to losartan, an insurmountable AT1-antagonist, and also to enalapril, an angiotensin-converting enzyme inhibitor. In addition, ME3221 reduced the systolic blood pressure more effectively than the two reference drugs.

Topics: Angiotensin Receptor Antagonists; Animals; Antihypertensive Agents; Biphenyl Compounds; Blood Pressure; Brain; Cerebrovascular Disorders; Enalapril; Heart; Hypertension; Imidazoles; Kidney; Losartan; Male; Myocardium; Rats; Rats, Inbred SHR; Tetrazoles

Our previous studies showed that imidapril prevented the occurrence of cerebral stroke and ameliorated biochemical parameter changes of renal dysfunction at a dose that did not inhibit the progression of hypertension in salt-loaded stroke-prone spontaneously hypertensive rats (SHRSP). To confirm these findings, a histopathological investigation was conducted on the kidney of salt-loaded (from 11 to 16 weeks of age) SHRSP, which was the subject of the preceding study. Their brains and hearts were also examined. Histopathologically, renal lesions such as fibrinoid necrosis and proliferative arteritis of small calibration arteries, necrotizing glomerulitis and tubular degeneration, and cerebral hemorrhage and slight cardial hypertrophy were observed in salt-loaded control SHRSP. The occurrence of these lesions were prevented in a dose-dependent manner by the administration of imidapril (1 and 2 mg/kg/day). Especially, the preventive effects on the renal lesions were apparently noted. Enalapril also prevented these renal lesions, but its preventive effects were weaker than those of imidapril at the same dose (2 mg/kg/day). It became evident from the results of the present and previous studies that imidapril reduced renal biochemical and histopathological injuries.

Topics: Animals; Antihypertensive Agents; Autopsy; Basilar Artery; Brain; Cerebrovascular Disorders; Disease Models, Animal; Dose-Response Relationship, Drug; Enalapril; Heart; Hypertension, Renal; Imidazoles; Imidazolidines; Kidney; Kidney Function Tests; Kidney Glomerulus; Male; Microscopy, Fluorescence; Myocardium; Organ Size; Rats; Rats, Inbred SHR; Sodium Chloride, Dietary

Topics: Aged; Cerebrovascular Disorders; Chemical and Drug Induced Liver Injury; Enalapril; Female; Humans; Lisinopril

It has been reported that some angiotensin converting enzyme inhibitors can prevent stroke-prone spontaneously hypertensive rats from stroke at much higher doses than clinical doses used for hypertension therapy. This study was performed to investigate the prophylactic effectiveness of imidapril against stroke in comparison with enalapril.. Salt-loaded stroke-prone spontaneously hypertensive rats were orally given imidapril (0.5, 1, 2, and 5 mg/kg per day), enalapril (2 and 5 mg/kg per day), or hydralazine (5 mg/kg per day). Stroke signs were scored, and blood pressure, protein concentration, and N-acetyl-beta-D-glucosaminidase activity in urine were measured. After 2 weeks of medication, angiotensin converting enzyme activities in the aorta were measured 24 hours after dosing.. In the control group, severe hypertension developed, and all rats died within 12 weeks because of stroke. Imidapril and enalapril dose-dependently decreased the stroke-related mortality, and both agents at 5 mg/kg per day showed excellent prophylaxis, although they did not inhibit hypertensive development. Imidapril at 0.5 mg/kg per day significantly prevented stroke to almost the same extent as enalapril at 2 mg/kg per day or hydralazine at 5 mg/kg per day. Imidapril dose-dependently suppressed the elevation of the two urinary indexes, which was followed by stroke. Imidapril inhibited enzyme activity in the aorta more strongly than did enalapril at the same dose.. Imidapril prevented the incidence of stroke in stroke-prone spontaneously hypertensive rats at a dose of 0.5 mg/kg per day or more by amelioration of kidney dysfunction. Reduction of blood pressure is not necessary, although enzyme inhibition in the vasculature may partly relate to the effect.

Topics: Acetylglucosaminidase; Angiotensin-Converting Enzyme Inhibitors; Animals; Cerebrovascular Disorders; Dose-Response Relationship, Drug; Drug Administration Schedule; Enalapril; Imidazoles; Imidazolidines; Incidence; Male; Rats; Rats, Inbred SHR

Many of the disorders in urinary, biochemical, and hematological parameters induced by salt-loading in stroke-prone spontaneously hypertensive rats (SHRSP) were significantly ameliorated by chronic treatment with angiotensin converting enzyme inhibitors, imidapril (1 and 2 mg/kg) and enalapril (2 mg/kg). Through the improvement of these parameters, the treatment reduced the incidence of stroke but did not suppress the development of hypertension. These results suggest that the prophylaxis of stroke in SHRSP is probably due to systemic improvement as judged from the parameters of renal functions.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Cell Count; Blood Pressure; Cerebrovascular Disorders; Disease Susceptibility; Electrolytes; Enalapril; Hypertension; Imidazoles; Imidazolidines; Kidney; Male; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Sodium, Dietary

We examined whether the renal protective effect of the angiotensin I converting enzyme inhibitor enalapril in stroke-prone spontaneously hypertensive rats (SHRSP) is dose-related and associated with alterations in the urinary excretion of prostaglandin (PG) E2 and 6-keto-PGF1 alpha, a stable breakdown product of prostacyclin. Enalapril maleate at 1.5, 5 and 15 mg/kg/day or vehicle was chronically administered to saline-drinking SHRSP (six per group) starting at 8.1 weeks of age. Vehicle-treated SHRSP developed severe hypertension, proteinuria and strokes (age at death, 14 +/- 1 weeks; mean +/- S.E.). Enalapril prolonged survival dose-dependently and reduced proteinuria; all SHRSP given 15 mg/kg/day lived beyond 23 weeks of age without evidence of stroke or proteinuria. There was no effect of enalapril at any dose on systolic arterial blood pressure in spite of variable levels of urinary protein excretion and onset of stroke in the different groups. Likewise, urinary 6-keto-PGF1 alpha and PGE2 excretion did not differ among the groups except for an increase in 6-keto-PGF1 alpha in the 15 mg/kg/day group at one week after initiation of enalapril therapy. These results are consistent with a dose-related renal protective action of enalapril in saline-drinking SHRSP that is not closely associated with sustained alterations in urinary excretion of renal vasodilatory PGs.

Topics: Animals; Blood Vessels; Cerebrovascular Disorders; Enalapril; Hypertension; Kidney; Male; Prostaglandins; Proteinuria; Rats; Rats, Inbred SHR

In the present study we examined whether the angiotensin I converting enzyme inhibitor, captopril, would protect stroke-prone spontaneously hypertensive rats (SHRSP) from stroke and renal pathology over a 26-week period. In the control group of six untreated SHRSP fed Stroke-Prone Rodent Diet and 1% NaCl drinking solution, all animals developed severe hypertension and stroke by 16.1 weeks of age. In eight salt-loaded SHRSP treated with oral captopril (50 mg/kg/day) beginning at 8.4 weeks of age, systolic blood pressure was slightly but temporarily suppressed and then continued to rise; by 12 weeks of age systolic blood pressure reached levels of severe hypertension, 240 +/- 8 mm Hg, and did not differ from that of untreated SHRSP. No deaths or brain lesions were noted in captopril-treated SHRSP despite severe hypertension maintained through 26 weeks of age when the study ended. Captopril treatment prevented increases in urinary protein excretion (14 +/- 2 v 63 +/- 16 mg/day at 11.7 weeks of age, P less than .01) and the severe brain, renal, and cardiac vascular lesions observed in untreated SHRSP. When maintained on Stroke-Prone Rodent Diet and saline, plasma renin activity of untreated SHRSP surviving until 14.5 weeks of age was markedly increased (29.1 +/- 9.4 ng Ang I/mL/h) compared with either untreated SHRSP (9.2 +/- 2.5 ng Ang I/mL/h, P less than .01) or Wistar-Kyoto rats (3.5 +/- 1.0 ng Ang I/mL/h, P less than .01) maintained on standard diet and water.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Administration, Oral; Animals; Blood Pressure; Brain; Captopril; Cerebrovascular Disorders; Enalapril; Heart; Hypertension; Hypotension; Kidney; Male; Myocardium; Potassium; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Renin; Risk Factors; Sodium

The influence of chronic treatment with the angiotensin I converting enzyme (ACE) inhibitor enalapril on blood pressure, kidney function, and survival was examined in stroke-prone spontaneously hypertensive rats (SHRSP). Male SHRSP that were fed a Japanese rat chow plus a 1% NaCl drinking solution beginning at 7-8 weeks of age developed severe hypertension and stroke; 14 of 18 untreated control SHRSP died by 14 weeks of age and exhibited evidence of cerebrovascular lesions. When enalapril (15 mg/kg/day) was included in the drinking solution of 15 SHRSP, blood pressure was initially reduced by only a slight degree, whereas survival improved markedly; only one of 10 SHRSP died before the rest were killed at 18 to 21 weeks. The remaining five enalapril-treated SHRSP lived beyond 36 weeks and on histological examination exhibited no evidence of cerebrovascular lesions. Chronic enalapril treatment also prevented the greater urinary excretion of protein and severe renal lesions observed in untreated SHRSP but did not affect urinary salt and water excretion. In anesthetized rats, glomerular filtration rate and tubular reabsorption of water were lower in untreated control SHRSP when compared with enalapril-treated SHRSP. Mean arterial pressure was comparable in both groups. These data support a possible role for ACE inhibition in the prevention of stroke and maintenance of kidney function independent of any marked change in blood pressure of SHRSP. Whether the protective effects of ACE inhibition relate to reduced angiotensin II formation, increased tissue kinins, or another mechanism remains to be determined.

Topics: Angiotensin II; Animals; Blood Pressure; Cerebrovascular Disorders; Enalapril; Glomerular Filtration Rate; Hypertension; Kidney; Male; Rats; Rats, Inbred SHR; Sodium Chloride

Topics: Animals; Blood Pressure; Captopril; Cerebrovascular Disorders; Enalapril; Hypertension, Renal; Kidney Diseases; Kinins; Male; Rats; Rats, Inbred SHR

Using an in vitro pressurized technique, we measured the myogenic pressure range and degree of myogenic activity in posterior cerebral arteries from stroke-prone spontaneously hypertensive rats (SHRSP) and rats of the same strain maintained by antihypertensive therapy. Treatment lowered the upper myogenic pressure limit and increased the strength of the myogenic response to levels comparable with those previously found in normotensive (Wistar-Kyoto, WKY) rats, suggesting that blood pressure history is the primary determinant of myogenic properties in the cerebral circulation.

Topics: Animals; Blood Pressure; Cerebral Arteries; Cerebrovascular Disorders; Enalapril; Hypertension; Male; Rats; Rats, Inbred SHR; Rats, Inbred Strains

Antihypertensive effect of enalapril (MK-421), an orally active non-sulfhydryl-containing converting enzyme inhibitor, was examined in stroke-prone spontaneously hypertensive (SHRSP) rats. The treatment was started at 14-15 weeks of age with tail blood pressure over 240 mmHg and was continued for 11 weeks. We used captopril as the reference drug. The dose of enalapril and captopril was 10 and 30 mg/kg per day, p.o., respectively. Enalapril showed a sustained antihypertensive effect from the 1st to the 11th week of the treatment. This antihypertensive effect was substantiated by the good increase in body weight; decrease in heart weight; decrease in incidences of vascular disease, nephrosclerosis, stroke and death. Enalapril treatment also prevented the increases in urine volume, and excretion of osmotically active solutes, Na, Cl and K with age. Captopril treatment showed about the same antihypertensive effect. No side effects were seen in the enalapril or captopril treated group. The antihypertensive potency of enalapril was about 3 times more than that of captopril. Enalapril and captopril slightly increased plasma renin concentration. Urinary excretion of PGE2 was not changed by enalapril or captopril treatment. These results clearly demonstrate the efficacy of long-term treatment with enalapril to prevent development of malignant hypertensive cardiovascular disease in SHRSP rats.

Topics: Animals; Blood Pressure; Body Weight; Cerebrovascular Disorders; Dinoprostone; Electrolytes; Enalapril; Heart Rate; Male; Prostaglandins E; Rats; Rats, Inbred SHR; Renin; Time Factors

Urinary excretion of kinins in stroke-prone spontaneously hypertensive (SHRSP) rats was unchanged during oral enalapril (10 mg/kg) or captopril (30 mg/kg) treatment once a day for 8 days compared to vehicle treatment. However, a significant decrease in urinary kinin excretion was observed on the 5th and 7th day compared to the pretreatment value in rats treated with enalapril. Both enalapril and captopril produced a significant reduction in blood pressure when compared to the vehicle. These findings provide no positive evidence to support the hypothesis of possible involvement of renal kinins in the antihypertensive effect of converting enzyme inhibitors in SHRSP rats.

Topics: Animals; Captopril; Cerebrovascular Disorders; Electrolytes; Enalapril; Hypertension; Kinins; Male; Potassium; Rats; Rats, Inbred SHR; Sodium; Time Factors